Dictionary of Mining, Mineral, and Related Terms

Dictionary of Mining, Mineral, & Related Terms Compiled and edited by the Staff of the U.S. Bureau of Mines Second Edit...

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Dictionary of Mining, Mineral, & Related Terms Compiled and edited by the Staff of the U.S. Bureau of Mines Second Edition U.S. DEPARTMENT OF THE INTERIOR 1996 As the Nation's principal conservation agency, the Department of the Interior has responsibility for most of our nationally owned public lands and natural resources. This includes fostering the sound use of our land and water resources; protecting our fish, wildlife, and biological diversity; preserving the environmental and cultural values of our national parks and historical places; and providing for the enjoyment of life through outdoor recreation. The Department assesses our energy and mineral resources and works to assure that their development is in the best interests of all our people by encouraging stewardship and citizen participation in their care. The Department also has a major responsibility for American Indian reservation communities and for people who live in island territories under U.S. administration. U.S. DEPARTMENT OF THE INTERIOR Bruce Babbitt, Secretary U.S. BUREAU OF MINES Rhea Lydia Graham, Director

FOREWORD The need for a revised mining dictionary is obvious when one considers the technological advances, environmental regulations, and other changes that have occurred since the Bureau's previous mining dictionaries were published. The Bureau had pioneered efforts in this field, beginning in 1918 with Fay's "Glossary of the Mining and Minerals Industry," and continuing to the 1968 publication "A Dictionary of Mining, Minerals, and Related Terms." To develop a modern mining dictionary, the U.S. Bureau of Mines initiated a collaborative project with the American Geological Institute. The Bureau's staff, the Institute's staff and members, and many minerals experts throughout the Nation contributed their expertise to this work. In the 5-year project's final phase, more than 100 2

Bureau personnel were involved in the technical review and publication production process. I would like to thank all those who assisted in producing this new mining dictionary, especially the Dictionary Revision Group members and the Bureau's engineers, scientists, and editors. The CD-ROM version of the Dictionary Revision is one of the last publications of the U.S. Bureau of Mines. Although the agency is closing, the Bureau's minerals information functions will transfer to the U.S. Geological Survey. I believe this new dictionary will benefit the Nation by continuing one of the Bureau of Mines important missions, that of providing information on minerals, the building blocks of our modern society, and mining, one of the world's oldest industries. Rhea Lydia Graham Director January 1996

PREFACE Technological developments and environmental laws and regulations that affect mining have proliferated during the past 25 years. Concurrently, the need for a modern mining dictionary has grown--one that incorporates not only standard mining-related terms but also terms in peripheral areas, such as the environment, pollution, automation, health and safety. The new edition of the Dictionary of Mining and Mineral Related Terms is the culmination of a 5-year effort between the U.S. Bureau of Mines and the American Geological Institute (USBM CONTRACT NUMBER J0101017) that will serve the needs of those engaged in minerals-related activities. It is organized to aid the user in appreciating the essential role that minerals and their products play in our quality of life. The Bureau's development of mining dictionaries dates back to Albert Fay's Glossary of the Mining and Mineral Industry, which first appeared in December 1918. That glossary contained about 18,000 terms. In 1968, the Bureau published A Dictionary of Mining, Mineral, and Related Terms, edited by Paul W. Thrush, with about 55,000 terms. The 1968 dictionary contained many new mining terms and terms from such related areas as metallurgy, ceramics, and glassmaking. That edition was as complete as possible with regard to technical and regional terms, historical terms, foreign terms that attained general usage in the United States, and terminology from the entire English-speaking world. For the past three decades that work has stood as the definitive authority on mineral-related terms. The 1996 edition reflects a departure from the previous one in scope and in format. This edition, containing some 28,500 terms, is not meant to be exhaustive in its coverage. It focuses on mining-related terms and excludes such related categories as ceramics, glass, metallurgy, petroleum, and other specialized disciplines. Geological terms which relate to mining are included, as are minerals which have a commercial value or which are 3

associated with such minerals. Many chemicals and materials that are not usually connected with mining or minerals processing do not appear, nor do the chemical elements unless they are classified as minerals. Abbreviations and acronyms have largely been excluded, because they usually are explained and defined within the context of an individual report. The front material, however, includes a list of abbreviations used in the definitions. New terms on marine mining, leaching, and automation appear in this edition as do a plethora of pollution and environmental terms, many of which have a legal definition based on law or regulation. The task of deciding which terms should be deleted from this edition, how to ensure the collection of new terms since 1968, and how to cull terms for inclusion was formidable. Terms from the 1968 edition were categorized by computer, and each category was reviewed by at least one subject specialist. The reviewers judged which terms should be retained or deleted, and they revised definitions as necessary and defined new terms. Final judgment on the inclusion of existing terms or the addition of new ones was left to the collective discretion of a panel of experts called the Dictionary Review Group. This group also examined the Society of Mining Engineers' Mining Engineering Handbook, 1993 edition, to ensure that the most modern terms and their definitions would be considered.

ACKNOWLEDGMENTS Specialists in many aspects of mining have volunteered their help in bringing the widely used "Dictionary of Mining, Mineral, and Related Terms" up to date, by reviewing definitions, adding new terms, recommending corrections, and citing references. Hundreds of specialists contributed to the new edition. The mining and minerals community owes special gratitude to the members of the Dictionary Revision Group: Robert L. Bates; V. A. Cammarota; M. Elizabeth Clare; John DeYoung, Jr.; James F. Donahue; Charles D. Hoyt; Tim O'Neil; Eugene Palowitch; John W. Padan; Gloria Ruggiero; Al Schreck; Robert Tuchman; and Dirk Van Zyl.

ABBREVIATIONS Abbreviations of certain terms, place names, and units of measure are used in the definitions as follows: Abbrev.

abbreviation

adj.

adjective

Ant.

antonym

CF:

compare

e.g.

for example 4

esp.

especially

et al.

and others

etc.

and so forth

Etymol.

etymology

i.e.

that is

Pl.

plural

Pron.

pronunciation

q.v.

which see

Sing.

singular

sp gr

specific gravity

specif.

specifically

Syn: or syn. synonym v. or V.

verb

var.

variant Place names

Arg

Argentina.

Aust

Australia.

Belg

Belgium.

Berks

Berkshire, England.

Bol

Bolivia.

Braz

Brazil.

Brist

Bristol Coalfield, England.

Can

Dominion of Canada.

Cent. Am

Central America.

Ches

Cheshire, England. 5

Clev

Cleveland iron district, England.

Colom

Republic of Colombia.

Corn

Cornwall, England.

Cumb

Cumberland Coalfield, England.

Derb

Derbyshire Coalfield, England.

Dev

Devonshire, England.

E. Ind

East Indies.

Eng

England.

Forest of Dean Forest of Dean Coalfield, England. Fr

French.

Ger

German.

Gr. Brit

Great Britain.

Glouc

Gloucestershire Coalfield, England.

Hid

Hidalgo, Mex.

Hind

Hindustan.

Ire

Ireland.

It

Italian.

Kent

Kent, England.

Lanc

Lancashire Coalfield, England.

Leic

Leicestershire, England.

Mex

Mexico.

Mid

Midland Coalfield, England.

Newc

Newcastle Coalfield, England.

N.S.W.

New South Wales, Australia.

N.Z.

New Zealand. 6

Norf

Norfolk, England.

N. of Eng

North of England.

N. Staff

North Staffordshire Coalfield, England.

Northumb

Northumberland Coalfield, England.

N. Wales

North Wales.

Pac

Pacific Coast, U.S.A.

Pat

Patagonia, South America.

Port

Portuguese (mostly in Brazil).

Prov

Provincial, United States, unless otherwise specified.

Pr

Prussian.

Russ

Russia.

Scot

Scotland.

Shrop

Shropshire, England.

S. Afr

Republic of South Africa.

S. Am

South America.

S. Staff

South Staffordshire, England.

S. Wales

South Wales, Great Britain.

Som

Somerset, England.

Sp

Spanish origin but not necessarily used in Spain.

Sp Am

Spanish America.

Staff

Staffordshire, England.

Suff

Suffolk, England.

Sw

Swedish.

Trans

Transvaal, Republic of South Africa.

U.K.

United Kingdom of Great Britain and Northern Ireland. 7

U.S.

United States of America.

U.S.S.R.

Former Union of Soviet Socialist Republics.

Venez

Venezuela.

W. Afr

West Africa.

War

Warwickshire, England.

York

Yorkshire, England. United States

AL Alabama

ME Maine

OR

Oregon

AK Alaska

MD Maryland

PA

Pennsylvania

AZ Arizona

MA Massachusetts

RI

Rhode Island

AR Arkansas

MI

SC

South Carolina

CA California

MN Minnesota

SD

South Dakota

CO Colorado

MS

TN

Tennessee

TX

Texas

CT

Michigan

Mississippi

Connecticut MO Missouri

DE Delaware

MT Montana

UT

Utah

FL

NE

Nebraska

VT

Vermont

GA Georgia

NV

Nevada

VA

Virginia

HI

Hawaii

NH

New Hampshire WA Washington

ID

Idaho

NJ

New Jersey

IL

Illinois

NM New Mexico

WI

IN

Indiana

NY

New York

WY Wyoming

IA

Iowa

NC

North Carolina

CZ

Canal Zone

KS

Kansas

ND

North Dakota

DC

District of Columbia

KY Kentucky

OH

Ohio

GU

Guam

LA Louisiana

OK

Oklahoma

PR

Puerto Rico

Florida

WV West Virginia Wisconsin

8

VI

Virgin Islands

Canada AB

Alberta

BC

British Columbia

LB

Labrador

MB Manitoba NB

New Brunswick

NF

Newfoundland

NT

Northwest Territories

ON Ontario PE

Prince Edward Island

PQ

Quebec

SK

Saskatchewan

UT

Yukon Territory

Units of Measure Abbreviations for Compound Units Two types of compound unit abbreviations are common. 1. In the metric system, many units comprise a basic unit, such as "m" (meter) modified by a prefix that acts as a "power of ten" multiplier. Thus "cm" is a "centi" "meter", onehundredth of a meter or 102 meter. Several compound metric units are widely used in this volume: mum *

micrometer(s)

cm

centimeter(s)

kJ

kilojoule(s)

km

kilometer(s) 9

kPa

kilopascal(s)

MJ

megajoule(s)

mL

milliliter(s)

mm

millimeter(s)

mPa

megapascal(s)

* No Greek letter symbols appear 2. Complex units are developed by multiplying or dividing units. The metric units for momentum, for example, are kg-m/s, which is read Newton meters per second.

Abbreviations for Units of Measure degrees C

degrees Celsius

degrees F

degrees Fahrenheit

A

ampere(s)

atm

standard atmosphere

AU

astronomical unit

bbl

barrel(s)

Bcf

billion cubic feet (gas flow)

Bcfd

billion cubic feet per day (gas flow)

Bcfy

billion cubic feet per year (gas flow)

Btu

British thermal unit(s)

Bunit

billion unit(s)

c

cycle(s)

c

centi (one-hundredth); prefix only

C

coulomb(s)

cal

calorie(s)

cd

candela(s) 10

Ci

curie(s)

cmil

circular mil

cp

candlepower

cpm

count(s) per minute

cps

count(s) per second

d

day(s)

d

deci (one-tenth); prefix only

D

darcy(s)

dB

decibel(s)

dyn

dyne(s)

eV

electron volt(s)

F

fermi(s)

F

farad(s)

fc

footcandle(s)

fl oz

fluid ounce(s)

ft

foot/feet

ft/s

foot/feet per second

ft2

square foot/feet

ft-lbf

foot pound(s) (force)

g

gram(s)

g, G

Gal (gravity constant)

G

giga (one billion); prefix only

gal

gallon(s)

Gs

gauss

h

hour(s) 11

ha

hectare(s)

H.E.

high explosive(s)

hp

horsepower

hp-h

horsepower hour

Hz

cycle(s) per second

in Hg

inch(es) of mercury

in

inch(es)

in H2O

inch(es) of water

J

joule(s)

k

kilo (one thousand); prefix only

K

kelvin

l

liter(s)

L

liter(s) (preferred form)

L

lambert(s)

lb

pound(s)

lbf

pound(s) force

lbf-ft

pound(s) force foot

lt

long ton(s)

m

meter

m

milli (one-thousandth); prefix only

M

mega (one million)

Mcf

thousand cubic feet (gas flow)

Mcfd

thousand cubic feet per day

mho

mho(s)

mi

mile(s) 12

mil

thousandth of an inch

MMbbl

million barrels

MMcf

million cubic feet (gas flow)

MMcfd

million cubic feet per day (gas flow)

MMcfy

million cubic feet per year (gas flow)

mol

mole(s)

mol wt

mole weight

mol %

mole percent

mpg

mile(s) per gallon

mph

mile(s) per hour

Mx

maxwell(s)

n

nano (one-billionth); prefix only

n

refractive index

N

Newton(s)

nmi

nautical mile(s)

Oe

oersted(s)

ohm-cmil/ft

ohm circular mil per foot

oz

ounce(s)

p

pico (one-trillionth); prefix only

P

poise(s)

Pa

pascal(s)

pct

percent

ppb

part(s) per billion

ppm

part(s) per million

psi

pound(s) (force) per square inch 13

psia

pound(s) force per square inch, absolute

psig

pound(s) force per square inch, gauge

r

revolution(s)

R

roentgen(s)

rad

radian(s)

rpm

revolutions per minute

s

second(s)

S

siemens(s)

sr

steradian(s)

st

stere(s)

st

short ton(s)

St

stokes

std ft3

standard cubic foot/feet

t

metric ton(s)

t/w-h

metric ton(s) per worker hour

t/w-d

metric ton(s) per worker day

T

tesla(s)

tr oz

troy ounce(s)

unit-1

reciprocal unit

unit2

square unit (or unit squared)

unit3

cubic unit

W

watt(s)

Wb

weber(s)

wt %, wt pct weight percent yd

yard(s) 14

yr

year(s)

Legislation Related to Mining and Minerals Clean Air Act of 1970 Clean Air and Water Act Amendments of 1977 Comprehensive Env. Response Comp., & Liability Act (CERCLA) Deep Seabed Hard Mineral Resources Act of 1980 Endangered Species Act of 1973 Federal Land Policy & Management Act of 1976 Federal Mine Safety and Health Act of 1977 Federal Water Pollution Control Act of 1972 Law of the Sea Treaty Mineral Leasing Act for Acquired Lands Mining Law of 1872 National Environmental Policy Act of 1969 (NEPA) Outer Continental Shelf Lands Act of 1953 Resource Conservation & Recovery Act of 1976 (RCRA) Submerged Lands Act of 1953 Superfund Amendments & Reauthorization Act of 1986 Surface Mining Control & Reclamation Act of 1977 (SMCRA) Toxic Substances Control Act of 1976 Uranium Mill Tailings Radiation Control Act, 1978 Water Quality Act of 1987

Organizations and Acronyms Air Pollution Control Association (APCA) American Association of Petroleum Geologists (AAPG) American Chemical Society (ACS) American Conference of Governmental Industrial Hygienists (ACGIH) American Electrochemical Society (AES) American Electromechanical Society (AES) American Electroplaters' Society (AES) American Foundrymen's Association (AFA) American Foundrymen's Society (AFS) American Gas Association (AGA) American Geological Institute (AGI) American Heritage Center (AHC) American Industrial Hygiene Association (AIHA) American Institute of Chemical Engineers (AIChE) American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. (AIME) American Iron and Steel Institute (AISI) American National Standards Institute (ANSI) (U.S. rep. to ISO) 15

American Petroleum Institute (API) American Public Health Association (APHA) American Society for Metals (ASM) American Society for Testing & Materials (ASTM) American Society of Civil Engineers (ASCE) American Society of Mechanical Engineers (ASME) American Society of Safety Engineers (ASSE) Association of Iron Ore Exporting Countries (AIOEC) Bituminous Coal Institute (BCI) Bituminous Coal Operators' Association (BCOA) Canada Centre for Mineral and Energy Technology (CANMET) Canada Institute of Mining and Metallurgy (CIM) Central Selling Organization (CSO) Commission of the European Communities (CEC) Commonwealth Scientific and Industrial Research Organisation (CSIRO) Conseil Intergouvernemental des Pays Exportateurs de Cuivre (CIPEC) Coordinating Research Council (CRC) Council for Scientific and Industrial Research (CSIR) Council on Environmental Quality (CEQ) Environmental Protection Agency (EPA) EROS Data Center European Coal and Steel Community (ECSC) European Community (EC) European Free Trade Association (EFTA) Federal Emergency Management Administration (FEMA) General Services Administration (GSA) Geological Society of America (GSA) GeoRef Information Services Geoscience Information Society (GIS) Illinois Institute of Technology Research Institute (IITRI) Independent Petroleum Association of America (IPAA) Institut National de l'Environnement Industriel et des Risques (INERIS) Institute of Electrical and Electronics Engineers (IEEE) Institute of Makers of Explosives (IME) Institute of Radio Engineers (IRE) Institution of Mining and Metallurgy (IMM) Instrument Society of America (ISA) Intergovernmental Panel on Climate Change (IPCC) International Copper Study Group International Energy Agency (IEA) International Labor Organization (ILO) International Lead and Zinc Study Group International Nickel Study Group International Organization for Standardization (ISO) International Tin Council (ITC) (defunct) 16

International Union of Pure and Applied Chemistry (IUPAC) International Union of Pure and Applied Physics (IUPAP) Joint Army-Navy-Air Force (JANAF) Lawrence Livermore Laboratories (LLL) Manufacturing Chemists Association (MCA) Massachusetts Institute of Technology (MIT) Mine Safety and Health Administration (MSHA) Minerals Management Service (MMS) National Academy of Sciences (NAS) National Coal Board (U.K.) (NCB) National Independent Coal Operators Association (NICOA) National Institute for Occupational Safety and Health (NIOSH) National Institute of Health (NIH) National Institute of Standards and Technology (NIST) National Labor Relations Board (NLRB) National Mine Rescue Association National Petroleum Association (NPA) National Petroleum Refiners Association (NPRA) National Research Council (NRC) National Science Foundation (NSF) National Stone Association (NSA) National Technical Information Service (NTIS) Northwest Mining Association (NWMA) Nuclear Regulatory Commission (NRC) Occupational Safety and Health Administration (OSHA) Occupational Safety and Health Review Commission (OSHRC) Office of Science and Technology Policy (OSTP) Office of Surface Mining Reclamation and Enforcement (OSM) Office of Technology Assessment (OTA) Organization of Arab Petroleum Exporting Countries (OAPEC) Organization of Petroleum Exporting Countries (OPEC) Society for Mining, Metallurgy, and Exploration, Inc. (SME) Society of Automotive Engineers (SAE) Society of Exploration Geophysicists (SEG) Standard Industrial Classification (SIC) Tennessee Valley Authority (TVA) The Minerals, Metals, and Materials Society (TMS) U.S. International Trade Commission Division of Minerals and Metals United Mine Workers of America (UMWA) United Nations Conference on Trade and Development (UNCTD) United States Bureau of Land Management United States Bureau of Mines (USBM) United States Geological Survey (USGS) United Steelworkers of America 17

A a a. Symbol in structural petrology for the direction of tectonic transport, similar to the direction in which cards might slide over one another. Striations in a slickensided surface are parallel to direction a. AGI b. A crystallographic axis: In the isometric system each axis is designated a; in hexagonal, tetragonal, and trigonal systems the nonunique axes are a; in the orthorhombic system a is always shorter than b with c either the longest or the shortest axis; in the monoclinic and triclinic systems a may be determined by one of several conventions. aa A Hawaiian term for lava consisting of a rough assemblage of clinkerlike scoriaceous masses. It is contrasted with pahoehoe used to designate the smoother flows. Pron. ah-ah. Fay; Hess a axis a. One of the three crystallographic axes used as reference in crystal description. It is oriented horizontally, front to back. b. One of the three reference axes used in describing a rock fabric possessing monoclinic symmetry, such as progressive simple shear. The a axis is the direction of tectonic transport, i.e., the direction of shear. Syn: a direction. CF: b axis; c axis. abandoned mine See: abandoned workings abandoned workings Excavations, either caved or sealed, that are deserted and in which further mining is not intended and open workings that are not ventilated and inspected regularly. Syn: abandoned mine. Federal Mine Safety abandonment Abandonment of a mining claim may be by failure to perform work, by conveyance, by absence, and by lapse of time. The abandonment of a mining claim is a question of intent. To constitute an abandonment of a mining claim, there must be a going away and a 18

relinquishment of rights, with the intention never to return and with a voluntary and independent purpose to surrender the location or claim to the next comer. CF: forfeiture Abbe jar In mineral processing, a porcelain jar used for laboratory batch grinding tests in ceramic ware. Pryor, 1 Abbe refractometer An instrument to determine the index of refraction of a liquid between two high-index glass prisms. CF: refractometer Abbe theory The visibility of an object under the microscope is directly proportional to the wavelength of light, and inversely to the aperture of lens. Pryor, 3 Abbe tube mill A gear-driven tube mill supported on a pair of riding rings and distinguished by an Archimedes spiral, through which the ore is fed and discharged. Grinding is effected by flint pebbles fed into the mill. See also: ball mill ABC system A method of seismic surveying by which the effect of irregular weathering thickness may be determined by a simple calculation from reciprocal placement of shotholes and seismometers. The method was originally used to solve refraction problems arising from irregularities in the top of the high-velocity layer. AGI Abel's reagent Etching agent consisting of 10% chromium trioxide in water. Used in the analysis of carbon steels. Bennett abernathyite A tetragonal mineral, K(UO2 )(AsO4 ).4H2 O ; in small yellow crystals; in the Temple Mountains, UT. aberration a. The failure of a lens or mirror to bring the light rays to the same focus. When aberration is due to the form of the lens or mirror, it is called spherical aberration. When 19

due to the different refrangibility of light of different colors, it is called chromatic aberration. When present in magnifiers it often causes inaccurate decisions as to flawlessness or color of gems. b. Distortion produced by a lens. It is spherical if a flat image appears closer to the viewer in the middle than toward the edges of the field of view. It is chromatic if the visible spectrum is spread to give both a red and a blue image. CF: achromatic; aplanatic lens; aplanachromatic lens. See also: chromatic aberration abime A large, steep-sided vertical shaft opening at the surface of the ground. AGI ablation breccia See: solution breccia A.B. Meco-Moore A bulky machine that cuts a deep web of coal up to 6 ft (1.8 m) and is used in cyclic mining in medium to thick seams. It runs on the floor of the seam and does not require a prop-free front. It carries two horizontal jibs, one cutting at floor level and the other at a height depending on seam conditions. Nelson Abney level A surveying instrument for taking levels up steep slopes; also used as a clinometer. Hammond abnormal place A working place in a coal mine with adverse geological or other conditions and in which the miner is unable to earn a wage, based on the pricelist, equal to or above the minimum wage. A term generally associated with stalls or pillar methods of working. Nelson abraser A device for assessing the wear resistance of surfaces. The specimen to be tested is rubbed alternately by the flat faces of two weighted abrasive wheels that revolve in opposite directions through frictional contact with the specimen and exert a combined abrasive, compressive, and twisting action twice in each revolution of the specimen holder. Osborne abrasion a. The mechanical wearing away of rock surfaces by friction and impact of rock particles transported by wind, ice, waves, running water, or gravity. Syn: corrasion b. The wearing 20

away of diamonds, drill-bit matrices, and drill-stem equipment by frictional contact with the rock material penetrated or by contact with the cuttings produced by the action of the drill bit in drilling a borehole. Long abrasion hardness Hardness expressed in quantitative terms or numbers indicating the degree to which a substance resists being worn away by frictional contact with an abrasive material, such as silica or carborundum grits. Also called abrasion resistance; wear resistance. Long abrasion index The percentage of a specially prepared 3-in by 2-in (76-mm by 51-mm) sample of coke remaining on a 1/8-in (3.2-mm) mesh British Standards test sieve after the sample of coke has been subjected to a standardized abrasion procedure in a rotating drum. BS, 1 abrasive a. Any natural or artificial substance suitable for grinding, polishing, cutting, or scouring. Natural abrasives include diamond, emery, garnet, silica sand, diatomite, and pumice; manufactured abrasives include esp., silicon carbide, fused alumina, and boron nitride. AGI b. Tending to abrade or wear away. AGI abrasive blasting respirator A respirator designed to protect the wearer from inhalation or impact of, and abrasion by, materials used or generated in abrasive blasting. ANSI abrasive formation A rock consisting of small, hard, sharp-cornered, angular fragments, or a rock, the cuttings from which, produced by the action of a drill bit, are hard, sharp-cornered, angular grains, which grind away or abrade the metal on bits and drill-stem equipment at a rapid rate. Syn: abrasive ground. Long abrasive ground See: abrasive formation abrasive hardness test Test employing a rotating abrasive wheel or plate against which specimens are held. The specimens are abraded for a given number of revolutions, and the weight of material lost is a measure of the abrasive hardness. Lewis 21

abraum salts See: abraumsalze abraumsalze Ger. Mixed sulfates and chlorides of potassium, sodium, and magnesium overlying the rock salt in the Stassfurt salt deposits. Syn: abraum salts; stripping salt. Holmes, 2 abriachanite An earthy, amorphous variety of crocidolite asbestos. Dana, 1 absolute a. In chemistry, free from impurity or admixture. Hess b. In physics, not dependent on any arbitrary standard. Hess c. Frequently used in the trades to indicate a thing as being perfect or exact. Abbrev. abs. Crispin absolute age The geologic age of a fossil organism, rock, or geologic feature or event given in units of time, usually years. Commonly used as a syn. of isotopic age or radiometric age, but may also refer to ages obtained from tree rings, varves, etc. Term is now in disfavor as it implies a certainty or exactness that may not be possible by present dating methods; i.e., two absolute ages for the same pluton may disagree by hundreds of millions of years. CF: relative age absolute atmosphere An absolute unit of pressure equal to 1 million times the pressure produced on 1 cm2 by the force of 1 dyn. Fay absolute bulk strength A measure of available energy per unit volume of explosive. Syn: bulk strength absolute chronology Geochronology in which the time-order is based on absolute age, usually measured in years by radiometric dating, rather than on superposition and/or fossil content as in relative chronology. AGI absolute daily range 22

During the 24 h of the day the difference between the maximum easterly and maximum westerly values of the magnetic declination at any point. Mason absolute humidity The content of water vapor in air, expressed as the mass of water per unit volume of air. CF: relative humidity absolute isohypse A line that has the properties of both constant pressure and constant height above mean sea level. Therefore, it can be any contour line on a constant-pressure chart, or any isobar on a constant-height chart. Hunt absolute ownership In law, an unqualified title to property and the unquestioned right to immediate and unconditional possession thereof. Applies to mining claims and properties. Standard, 2; Hess absolute permeability A measure of possible flow of a standard liquid under fixed conditions through a porous medium when there is no reaction between the liquid and the solids. This measure is arbitrarily taken for isothermal viscous flow. It can be duplicated with gases if tests are so conducted that extrapolation to infinite pressure can be made; specific permeability. Hess absolute potential True potential difference between a metal and the solution in which it is immersed. Pryor, 3 absolute pressure a. Total pressure at a point in a fluid equaling the sum of the gage pressure and the atmospheric pressure. Webster 3rd b. Pressure measured with respect to zero pressure, in units of force per unit of area. CTD absolute roof The entire mass of strata overlying a coal seam or a subsurface point of reference. See also: nether roof absolute scale 23

See: Kelvin temperature scale absolute temperature Temperature reckoned from absolute zero. See also: temperature. Handbook of Chemistry and Physics, 2 absolute time Geologic time measured in terms of years by radioactive decay of elements. CF: relative time absolute viscosity See: viscosity coefficient absolute weight strength A measure of available energy per gram of explosive. Syn: weight strength absolute zero The temperature at which a gas would show no pressure if the general law for gases would hold for all temperatures. It is equal to -273.16 degrees C or -459 degrees F. CF: temperature. Handbook of Chemistry and Physics, 2 absorbed water Water held mechanically in a soil mass and having physical properties not substantially different from those of ordinary water at the same temperature and pressure. ASCE absorbent formation A rock or rock material, which, by virtue of its dryness, porosity, or permeability, has the ability to drink in or suck up a drilling liquid, as a sponge absorbs water. Syn: absorbent ground absorbent ground See: absorbent formation absorbents

24

Substances, such as wood meal and wheat flour, that are forms of low explosive when mixed with metallic nitrates and tend to reduce the blasting power of the explosives, making them suitable for coal blasting. Cooper absorber a. An apparatus in which gases are brought into intimate contact with an extended surface of an absorbing fluid so that they enter rapidly into solution. Hess b. The resistance and capacitance in series that is placed across a break in an electrical circuit in order to damp any possible oscillatory circuit and would tend to maintain an arc or spark when a current is interrupted. Syn: spark absorber c. Any material that absorbs or stops ionizing radiation, such as neutrons, gamma rays, alpha particles, and beta particles. Lyman absorptiometer A device for measuring the solubility of a gas in a liquid. Bennett absorption a. The phenomenon observed when a pleochroic mineral is rotated in plane polarized light. In certain positions, the mineral is darker than in others, owing to the absorption of light. b. In hydrology, a term applied to the entrance of surface water into the lithosphere by all methods. AGI c. The reduction of light intensity in transmission through an absorbing substance or in reflection from a surface. In crystals, the absorption may vary with the wavelength and with the electric vector of the transmitted light with respect to crystallographic directions. d. Any mechanism by which energy, e.g., electromagnetic or seismic, is converted into heat. e. Taking up, assimilation, or incorporation, e.g., of liquids in solids or of gases in liquids. CF: adsorption f. The entrance of surface water into the lithosphere by any method. absorption hygrometer A type of hygrometer with which the water vapor content of the atmosphere is measured by means of the absorption of vapor by a hygroscopic chemical. The amount of vapor absorbed may be determined in an absolute manner by weighing the hygroscopic material, or in a nonabsolute manner by measuring a physical property of the substance that varies with the amount of water vapor absorbed. The lithium chloride humidity strip and carbon-film hygrometer element are examples of the latter. Hunt absorption loss a. The loss of water occurring during initial filling of a reservoir in wetting rocks and soil. Hammond b. That part of the transmission loss due to dissipation or the conversion of sound energy into some other form of energy, usually heat. This conversion may take place within the medium itself or upon a reflection at one of its boundaries. Hy 25

absorption rate a. The rate, expressed in quantitative terms, at which a liquid, such as a drilling circulation medium, is absorbed by the rocks or rock materials penetrated by the drill bit. Long b. The amount of water absorbed when a brick is partially immersed for 1 min; usually expressed either in grams or ounces per minute. Also called suction rate; initial rate of absorption. ACSG, 1 absorption spectra Specific wavelengths of electromagnetic radiation have precisely the energy to cause atomic or molecular transitions in substances they are passing through; their removal from the incident radiation produces reductions in intensity of those wavelengths, or absorption spectra, characteristic of the substance under study. CF: emission spectra absorption spectrum The array of absorption bands or lines seen when a continuous spectrum is transmitted through a selectively absorbing medium. AGI absorption tower A tower in which a liquid absorbs a gas. abundant vitrain A field term denoting, in accordance with an arbitrary scale established for use in describing banded coal, a frequency of occurrence of vitrain bands comprising 30% to 60% of the total coal layer. CF: dominant vitrain; moderate vitrain; sparse vitrain. AGI abutment A surface or mass provided to withstand thrust, for example, the end supports of an arch or bridge. In coal mining, (1) the weight of the rocks above a narrow roadway is transferred to the solid coal along the sides, which act as abutments of the arch of strata spanning the roadway; and (2) the weight of the rocks over a longwall face is transferred to the front abutment (the solid coal ahead of the face) and the back abutment (the settled packs behind the face). See also: overarching weight; pressure arch; load transfer. Syn: arch structure abutment load In underground mining, the weight of rock above an excavation that has been transferred to the adjoining walls. Pryor, 3 26

abutment pillars Pillars intended to support vertical load in excess of the weight of the strata directly above them. Generally, these abutment pillars are large pillars adjacent to smaller pillars, sometimes called yield pillars, which are incapable of carrying the weight of the strata above them. SME, 1 abysmal See: abyssal abysmal sea That part of the sea occupying the ocean basins proper. Fay abyss a. A very deep, unfathomable place. The term is used to refer to a particularly deep part of the ocean, or to any part below 3,000 fathoms (18,000 ft or 5.5 km). Hunt b. Syn: pit; pot; pothole; chasm; shaft. abyssal a. Pertaining to an igneous intrusion that occurs at considerable depth, or to the resulting rock; plutonic. CF: hypabyssal b. Pertaining to the ocean environment or depth zone of 500 fathoms (3,000 ft or 915 m) or deeper; also, pertaining to the organisms of that environment. AGI c. Of, or pertaining to, deep within the Earth, the oceanic deeps below 1,000 fathoms (6,000 ft or 1.83 km), or great depths of seas or lakes where light is absent. See also: plutonic d. In oceanography, relating to the greatest depths of the ocean; relating to the abyssal realm. Syn: abysmal abyssal deposit A deposit of the deep sea, accumulating in depths of more than 1,500 fathoms (9,000 ft or 2.7 km) of water; these deposits comprise the organic oozes, various muds, and red clay of the deepest regions. CTD abyssal injection The process by which magmas, originating at considerable depths, are considered to have been driven up through deep-seated contraction fissures. abyssal plain

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An area of the ocean floor with a slope of less than 1 in 1,000 or flat, nearly level areas that occupy the deepest portions of many ocean basins. Schieferdecker abyssal realm The deep waters of the ocean below 1,000 fathoms or 6,000 ft (1.83 km). abyssal theory A theory of mineral-deposit formation involving the separation and sinking of ore minerals below a silicate shell during the cooling of the Earth from a liquid stage, followed by their transport to and deposition in the crust as it was fractured (Shand, 1947). Modern thought ascribes more complex origins to mineral deposits. AGI abyssal zone The marine-life zone of the deep sea embracing the water and bottom below a depth of 6,000 ft (1.83 km). Stokes abyssobenthic Relating to that part of the abyssal realm that includes the ocean floor; pertaining to or living on the ocean floor at great depths. CTD abyssolith See: batholith abyssopelagic a. Relating to that part of the abyssal realm that excludes the ocean floor; floating in the depths of the ocean. CTD b. Pertaining to that portion of the deep waters of the ocean that lie below depths of 6,000 ft (1.83 km). AGI acanthite A monoclinic mineral, 4[Ag2 S] ; dimorphous with argentite, pseudohexagonal, in slender prisms; sp gr, 7.2 to 7.3; a source of silver. accelerated weathering test A test to indicate the effect of weather on coal, in which the coal is alternately exposed to freezing, wetting, warming, and light; the alternation may be varied to suit. This test may be applied to other bituminous materials. Hess 28

accelerator a. A machine that accelerates electrically charged atomic particles, such as electrons, protons, deuterons, and alpha particles, to high velocities. Lyman b. A substance added to increase the rate of a chemical reaction. Nelson accelerometer A seismometer with response linearly proportional to the acceleration of earth materials with which it is in contact. AGI accented contour See: index contour acceptor A charge of explosives or blasting agent receiving an impulse from an exploding donor charge. Syn: receptor accessory a. Applied to minerals occurring in small quantities in a rock. The presence or absence of these minor minerals does not affect the classification or the naming of the rock. Holmes, 2 b. Fragments derived from previously solidified volcanic rocks of related origin; i.e., the debris of earlier lavas and pyroclastic rocks from the same cone. See also: accessory mineral c. Said of pyroclastics that are formed from fragments of the volcanic cone or earlier lavas; it is part of a classification of volcanic ejecta based on mode of origin, and is equivalent to resurgent ejecta. CF: auxiliary accessory element See: trace element accessory mineral Any mineral the presence of which is not essential to the classification of the rock. Accessory minerals generally occur in minor amounts; in sedimentary rocks they are mostly heavy minerals. CF: essential mineral. Syn: accessory accessory plate a. The quartz wedge inserted in the microscope substage above the polarizer in order to estimate birefringence and to determine optical sign of uniaxial minerals. CF: quartz wedge b. The selenite plate that gives the sensitive tint of a specimen between crossed 29

nicols. Pryor, 3 c. The mica plate that retards yellow light. Pryor, 3 d. In polarized-light microscopy, an optical device that may be inserted into the light train to alter light interference after passage through, or reflection by, a crystalline material; e.g., quartz wedge, mica plate, gypsum plate, or Bertrand lens. e. In polarized-light microscopy, an optical compensator that may be inserted into the light train to alter birefringence after light passage through or reflection by an anisotropic material; e.g., quartz wedge, mica plate, gypsum plate, or Berek compensator. Syn: gips plate; glimmer plate; compensator. CF: Berek compensator; gypsum plate. access road A route constructed to enable plant, supplies, and vehicles to reach a mine, quarry, or opencast pit. In remote and isolated regions, the provision of an access road may be very costly. Nelson accidental inclusion See: xenolith; xenocryst. accordion roller conveyor A roller conveyor with a flexible latticed frame that permits variation in length. accretion vein A vein formed by the repeated filling of a channelway and its reopening by the development of fractures in the zone undergoing mineralization. accumulation a. In coal mining, bodies of combustible gases that tend to collect in higher parts of mine workings and at the edge of goaves and wastes. They are found in cavities, at ripping lips, at other sheltered places protected from the ventilating current, and at the higher sides of rise faces. Mason b. The concentration or gathering of oil or gas in some form of trap. Commercial accumulation is a volume or quantity sufficient for profitable exploitation. AGI accumulative rock See: cumulate accumulator a. A cylinder containing water or oil under pressure of a weighted piston for hydraulic presses, hoists, winches, etc. It is between the pumps and the presses, keeps a constant 30

pressure on the system, and absorbs shocks. b. A storage battery. c. In oceanography, a spring of rubber or steel attached to a trawling warp, to lessen any sudden strain due to the trawl catching. CTD accumulator conveyor Any conveyor designed to permit accumulation of packages or objects. Usually roller, live roller conveyor, roller slat conveyor, or belt conveyor. accuracy The degree of conformity with a standard, or the degree of perfection attained in a measurement. Accuracy relates to the quality of a result, and is distinguished from precision, which relates to the quality of the operation by which the result is obtained. AGI acetamide A trigonal mineral, CH3 CONH2 . Syn: acetic acid amine; ethanamide. acetic acid amine See: acetamide acetylene The most brilliant of illuminating gases, C2 H2 . It may be produced synthetically from its elements, by incomplete combustion of coal gas, and commercially from calcium carbide, CaC2 . It also may be produced by reaction with water. Used in manufacturing explosives. Formerly used as an illuminating gas in mines and around drill rigs. When combined with oxygen, acetylene burns to produce an intensely hot flame and hence now is used principally in welding and metal-cutting flame torches. Syn: ethyne; ethine. CF: gas. Standard, 2; Bennett; Long acetylene lamp See: carbide lamp acetylene tetrabromide Yellowish liquid; CHBr2 CHBr2 ; sp gr, 2.98 to 3.00; boiling point, 239 to 242 degrees C with decomposition (at 760 mm); also, boiling point, 151 degrees C (at 54 mm); melting point, 0.1 degrees C; and refractive index, 1.638. Used for separating minerals by specific gravity; a solvent for fats, oils, and waxes; a fluid in liquid gases; and a solvent in microscopy. CCD, 2 31

achavalite Former name for iron selenide, FeSe . Acheson graphite Artificial graphite made from coke by electric furnace heating. Bennett Acheson process A process for the production of artificial or synthetic graphite. It consists of sintering pulverized coke in the Acheson furnace at 2,760 to 3,316 degrees C. Henderson achirite Former name for dioptase. achroite A colorless variety of elbaite tourmaline used as a gemstone. achromatic In microscopy, a compound lens that does not spread white light into its spectral colors. CF: aberration acicular a. A mineral consisting of fine needlelike crystals; e.g., natrolite. Nelson b. Slender needlelike crystal. c. Refers to needlelike crystals. CF: equant; sagenitic; tabular; rodlike. acicular bismuth See: aikinite acicular powder In powder metallurgy, needle-shaped particles. ASM, 1 aciculite See: aikinite acid 32

a. A solution of pH less than 7.0 at 25 degrees C. b. A substance containing hydrogen that may be replaced by metals with the formation of salts. CTD acid Bessemer converter One lined with acid refractories. acid bottom and lining The inner bottom and lining of a melting furnace, consisting of materials like sand, siliceous rock, or silica brick, which give an acid reaction at the operating temperature. Syn: acid lining acid clay a. A clay that is used mainly as a decolorant or refining agent, and sometimes as a desulfurizer, coagulant, or catalyst. b. A clay that yields hydrogen ions in a water suspension; a hydrogen clay. acid cure In uranium extraction, sulfation of moist ore before leaching. Pryor, 1 acid-dip survey A method of determining the angular inclination of a borehole in which a glass, testtubelike bottle partly filled with a dilute solution of hydrofluoric acid is inserted in a watertight metal case. When the assemblage is lowered into a borehole and left for 20 to 30 min, the acid etches the bottle at a level plane from which the inclination of the borehole can be measured. CF: Kiruna method. Syn: acid-dip test; acid test; acid-etch tube. Long acid-dip test See: acid-dip survey acid drainage Water with a pH of less than 6.0 and in which total acidity exceeds total alkalinity; discharged from an active, inactive, or abandoned surface coal mine and reclamation operation. acid electric furnace An arc furnace having an acid refractory hearth. 33

acid embrittlement A form of hydrogen embrittlement that may be induced in some metals by acid treatment. ASM, 1 acid-etch tube A soda-lime glass tube charged with dilute hydrofluoric acid, left in a borehole for 20 to 30 min to measure inclination as indicated by the angle of etch line on the tube. May be fitted in a clinometer. Syn: acid-etch vial; culture tube; etch tube; sargent tube. See also: acid-dip survey acid-etch vial See: acid-etch tube acid flux Metallurgically acid material (usually some form of silica) used as a flux. Bennett acid-forming materials Earth materials that contain sulfide minerals or other materials that, if exposed to air, water, or weathering processes, form acids that may create acid drainage. acidic a. A descriptive term applied to those igneous rocks that contain more than 60% silica. Acidic is one of four subdivisions of a widely used system for classifying igneous rocks based on their silica content: acidic, intermediate, basic, and ultrabasic. AGI b. Applied loosely to any igneous rock composed predominantly of light-colored minerals having a relatively low specific gravity. CF: felsic acidization The process of forcing acid into a limestone, dolomite, or sandstone in order to increase permeability and porosity by dissolving and removing a part of the rock constituents. It is also used to remove mud injected during drilling. The general objective of acidization is to increase productivity. Syn: acidizing acidize To treat a limestone or dolomitic formation with dilute hydrochloric acid to enlarge its void spaces. Wheeler, R.R. 34

acidizing See: acidization acid leach Metallurgical process for dissolution of metals by means of acid solution. Examples include extraction of copper from oxide- or sulfide-bearing ore and dissolution of uranium from sandstone ores. Acid leaching can occur on heap-leach pads or in situ. acid lining See: acid bottom and lining acid mine drainage a. Acidic drainage from bituminous coal mines containing a high concentration of acidic sulfates, esp. ferrous sulfate. See also: acid water b. Drainage with a pH of 2.0 to 4.5 from mines and mine wastes. It results from the oxidation of sulfides exposed during mining, which produces sulfuric acid and sulfate salts. The acid dissolves minerals in the rocks, further degrading the quality of the drainage water. AGI acid mine water a. Mine water that contains free sulfuric acid, mainly due to the weathering of iron pyrites. A pit water, which corrodes iron pipes and pumps, usually contains a high proportion of solids per gallon, principally the sulfates of iron, chiefly ferrous and alumina. See also: acid water b. Where sulfide minerals break down under chemical influence of oxygen and water, the mine drainage becomes acidic and can corrode ironwork. If it reaches a river system, biological damage may also result. Pryor, 3 acid neutralizers Calcium carbonate, CaCO3 , magnesium carbonate, MgCO3 , and china clay, which neutralize free acids, thereby preventing explosives from decomposing in storage. They also have a cooling effect and tend to reduce the sensitivity of the explosive. Cooper acid open-hearth steel Low-phosphorus pig iron treated in an acid (silica or sand)-lined furnace. Mersereau, 2 acid ore See: siliceous ore 35

acid process A steelmaking process--Bessemer, open-hearth, or electric--in which the furnace is lined with a siliceous refractory, and for which pig iron low in phosphorus is required, as this element is not removed. See also: acid steel; basic process. CTD acid-recovery operator In the coke products industry, a person who recovers sulfuric acid used in processing coke-gas byproducts by cooking sludge with steam in acid regenerator pots. Syn: acid regenerator acid refractory material A general term for those types of refractory material that contain a high proportion of silica; e.g., silica refractories (greater than 92% SiO2 ) and siliceous refractories (78% to 92% SiO2 ). The name derives from the fact that silica behaves chemically as an acid and at high temperatures reacts with bases such as lime or alkalies. Dodd acid refractory product Refractory product made of clay-silica mixture or pure silica. Rosenthal acid regenerator See: acid-recovery operator acid rock drainage Drainage that occurs as a result of natural oxidation of sulfide minerals contained in rock that is exposed to air and water. It is not confined to mining activities, but can occur wherever sulfide-bearing rock is exposed to air and water. Abbrev. ARD. acid slag Slag that contains substantial amounts of active silica. acid sludge Products of refining of tar, shale oil, and petroleum in which sulfuric acid reacts to form a sulfonic acid mixture, green acids, and mahogany acids and salts. Used in the flotation process and in proprietary collector agents for flotation of iron ores. Pryor, 1 acid soil 36

A soil with a pH of less than 7.0. AGI acid steel Steel melted in a furnace with an acid bottom and lining and under a slag containing an excess of an acid substance, such as silica. See also: acid process acid strength Related to ability to liberate hydrogen ions to solution, and hence to electrical conductivity of equivalent aqueous solutions of acids. Pryor, 3 acid test a. See: acid-dip survey b. A severe or decisive trial, as of usability or authenticity. Long acid water Water charged naturally with carbon dioxide. Also applied to natural waters containing sulfur compounds, esp. sulfates. See also: acid mine water; acid mine drainage. aciform Needle-shaped. aciniform A mineral aggregate shaped like a cluster of grapes. Also, full of small kernels like a grape. Syn: acinose; acinous. acinose a. Grapelike; applied to the structure of clustered mineral aggregates. Syn: aciniform; acinous. b. Granulated; like grape seeds; applied to the texture of some mineral aggregates. acinote Former name for actinolite. acinous See: aciniform; acinose. aclinal 37

A little-used term said of strata that have no inclination; horizontal. Syn: aclinic aclinic See: aclinal aclinic line The line through those points on the Earth's surface at which the magnetic inclination is zero. The aclinic line is a particular case of an isoclinic line. Hunt acmite A brown variety of aegirine having pointed terminations. See also: aegirine; pyroxene. acopolado Mex. Ore containing 50 to 60 oz/st (1.56 to 1.88 kg/t) of silver. Hess acoustic Used when the term that it modifies designates something that has the properties, dimensions, or physical characteristics associated with sound waves. Hy acoustical well logging Any determination of the physical properties or dimensions of a borehole by acoustical means, including measurement of the depth of fluid level in a well. AGI acoustic attenuation log In theory, a log designed to measure the manner in which the energy of elastic waves is dissipated in passing through rock. Although no practical log of this type has yet evolved, the belief that a log of this parameter would permit the estimation of the permeability of formations would seem to ensure such a development since no log has been developed to record permeability. Wyllie acoustic dispersion The change of speed of sound with frequency. Hunt acoustic impedance The acoustic impedance of a given surface area of an acoustic medium perpendicular, at every point, to the direction of propagation of sinusoidal acoustic waves of given 38

frequency, and having equal acoustic pressures and equal volume velocities per unit area at every point of the surface at any instance, is the quotient obtained by dividing (1) the phasor corresponding to the acoustic pressure by (2) the phasor corresponding to the volume velocity. See also: impedance acoustic interferometer An instrument for making physical observations upon standing waves. It may be used, e.g., to measure velocity, wavelength, absorption, or impedance. Hunt acoustic log A continuous record made in a borehole showing the velocity of sound waves over short distances in adjacent rock; velocity is related to porosity and nature of the liquid occupying pores. AGI acoustic-radiation pressure A unidirectional steady-state pressure exerted upon a surface exposed to an acoustic wave. Such a steady pressure is usually quite small in magnitude and is really observable only in the presence of very intense sound waves. Hunt acoustic radiometer An instrument for measuring acoustic-radiation pressure by determining the unidirectional steady-state force resulting from reflection or absorption of a sound wave at its boundaries. Hunt acoustic resistance Product of longitudinal wave velocity and density, being the property that controls the reflective power at a boundary plane. Schieferdecker acoustics The study of sound, including its production, transmission, reception, and utilization, esp. in fluid media such as air or water. With reference to Earth sciences, it is esp. relevant to oceanography. The term is sometimes used to include compressional waves in solids; e.g., seismic waves. AGI acoustic scattering The irregular reflection, refraction, or diffraction of sound waves in many directions. Hy acoustic sounding 39

The indirect evaluation of water depth, using the principle of measuring the length of time necessary for a sound wave to travel to the bottom, reflect, and travel back to the water surface. Hunt acoustic-strain gage An instrument for measuring strains; e.g., in concrete linings to shafts or roadways. It contains a length of fine wire under tension, the tension being varied by the strain to which the gage is subjected. The measurement made is that of the frequency of vibration of the wire when it is plucked by means of an electromagnetic impulse, and this measurement can be made with great accuracy. The gage is highly stable, and readings can be made over a period of years without any fear of zero drift. See also: electrical resistance strain gage; mechanical extensometer. Nelson acoustic theodolite An instrument designed to provide a continuous vertical profile of ocean currents at a specific location. Hunt acoustic wave a. The waves that contain sound energy and by the motion of which sound energy is transmitted in air, in water, or in the ground. The wave may be described in terms of change of pressure, of particle displacement, or of density. AGI b. Used increasingly to study the physical properties of rocks and composition of gases. Investigations may be made both in situ and in the laboratory. Nelson acquired lands Defined by the U.S. Department of the Interior as "lands in Federal ownership which were obtained by the Government through purchase, condemnation, or gift, or by exchange for such purchased, condemned, or donated lands, or for timber on such lands. They are one category of public lands." Public land laws are generally inapplicable to acquired lands. SME, 1 acre a. A measure of surficial area, usually of land. The statute acre of the United States and England contains 43,560 ft2 (4,840 yd2; 4,047 m2 ; or 160 square rods). The so-called Scotch acre contains about 6,150 yd2 (5,142 m2 ), and the Irish acre 7,840 yd2 (6,555 m2 ). There are various special or local acres in England (as in Cheshire or among the hop growers), varying from 440 yd2 (368 m2 ) to more than 10,000 yd2 (8,361 m2 ). Standard, 2 b. Can. In Quebec, a linear measure that equals the square root of 43,560, or approx. 208.7 ft (63.6 m). Fay c. For the calculation of coal reserves, a convenient rule is to 40

allow 1,200 st/ft (coal thickness) per acre (8,821 t/m/ha). For known and dependable areas, 1,500 st/ft per acre (11,027 t/m/ha) may be used. Nelson acreage rent Royalty or rent paid by the lessee for working and disposing of minerals at the rate of so much per acre. acre-foot The quantity of water that would cover 1 acre, 1 ft deep (1 ha, 13.6 cm deep). One acrefoot contains 43,560 ft3 (1,233 m3 ). acre-inch The volume of water, soil, or other material that will cover 1 acre, 1 in deep (1 ha, 1.1 cm deep). AGI acre-yield The average quantity of oil, gas, or water recovered from 1 acre (0.4 ha) of a reservoir. AGI actetic acid amine See: acetamide actinide A chemical element with atomic number greater than 88; all are radioactive. Syn: actinide element actinide element a. One of the group of chemical elements of increasing atomic number, starting with actinium (atomic number 89) and extending through atomic number 103. These elements occupy one single place in the extended periodic table, in the same group into which the rare-earth elements (lanthanides) are classified. See also: actinide b. One of the radioactive elements, atomic numbers 89 to 103. Hurlbut actinolite A monoclinic mineral, 2[Ca2 (Mg,Fe)5 Si8 O22 (OH)2 ] in the hornblende series Mg/(Mg+Fe2+ ) = 0.5 to 0.89 of the amphibole group; forms a series with tremolite; 41

green, bladed, acicular, fibrous (byssolite asbestos), or massive (nephrite jade); prismatic cleavage; in low-grade metamorphic rocks. Syn: actinote; strahlite. CF: tremolite actinote See: actinolite activated alumina Highly porous, granular aluminum oxide that preferentially absorbs liquids from gases and vapors, and moisture from some liquids. McGraw-Hill, 1 activated carbon Carbon, mostly of vegetable origin, and of high adsorptive capacity. Syn: activated charcoal activated charcoal See: activated carbon activated clay A clay whose adsorbent character or bleaching action has been enhanced by treatment with acid. CCD, 2 activated coal plow With a view to applying the coal plow to seams too hard to be sheared by the normal cutting blade, German mining engineers have developed various types of power-operated cutters. One consists of a series of compressed-air picks mounted above each other; another, of a resonance pattern, houses two high-speed motors eccentrically mounted and rotating in opposite directions. The latter imparts a vibration to the cutting edge equivalent to 2,500 blows per minute with a stroke of 3/16 to 1/4 in (4.8 to 6.4 mm) and a force of approx. 200 st (181 t). Mason activated plow See: Huwood slicer activating agent a. A substance that when added to a mineral pulp promotes flotation in the presence of a collecting agent. Syn: activator b. Reagent used particularly in differential mineral flotation to help cleanse the mineral surface so that a collector may adhere to it and 42

permit or aid its floatability. Frequently used to allow floating minerals that had been previously depressed. Mitchell activation a. In the flotation process of mineral dressing, the process of altering the surface of specific mineral particles in a mineral pulp to promote adherence of certain reagents. Pryor, 3 b. The changing of the passive surface of a metal to a chemically active state. CF: passivation c. In the flotation process of ore beneficiation, the process of altering the surface of specific mineral particles in an ore pulp to promote adherence of certain reagents. Henderson d. The process of making a material radioactive by bombardment with neutrons, protons, or other nuclear particles. See also: activation analysis activation analysis A method for identifying and measuring the chemical elements in a sample to be analyzed. The sample is first made radioactive by bombardment with neutrons, charged particles, or other nuclear radiation. The newly radioactive atoms in the sample give off characteristic nuclear radiations that can identify the atoms and indicate their quantity. See also: activation activator a. In flotation, a chemical added to the pulp to increase the floatability of a mineral in a froth or to refloat a depressed (sunk) mineral. Also called activating reagent. CTD b. A reagent that affects the surface of minerals in such a way that it is easy for the collector atoms to become attached. It has the opposite effect of a depressor. CF: depressor c. A substance that is required in trace quantities to impart luminescence to certain crystals. CCD, 2 d. Ions that are photon emitters. Van Vlack e. Any agent that causes activation. See also: activating agent. Bennett active agent Surface-active substance that immunizes solids against a parting liquid. Hess active earth pressure The minimum value of lateral earth pressure exerted by soil on a structure, occurring when the soil is allowed to yield sufficiently to cause its internal shearing resistance along a potential failure surface to be completely mobilized. See also: surcharge CF: passive earth pressure active entry

43

An entry in which coal is being mined from a portion thereof or from connected sections. USBM, 1 active fault One liable to further movement. CF: passive fault active layer a. The surficial deposit that undergoes seasonal changes of volume, swelling when frozen or wet, and shrinking when thawing and drying. AGI b. A surface layer of ground, above the permafrost, that is frozen in the winter and thawed in the summer. Its thickness ranges from several centimeters to a few meters. AGI active mining area a. The area, on and beneath land, used or disturbed in activity related to the extraction, removal, or recovery of coal from its natural deposits. This term excludes coal preparation plants, areas associated with coal preparation plants, and post-mining areas. SME, 1 b. The area in which active mining takes place relative also to extraction of metal ores, industrial minerals, and other minerals of economic value. active workings All places in a mine that are ventilated and inspected regularly. Federal Mine Safety activity a. In nuclear physics, the rate of decay of atoms by radioactivity. It is measured in curies. Bennett b. The ideal or thermodynamic concentration of a substance, the substitution of which for the true concentration, permits the application of the law of mass action. See also: ionization constant actual age See: absolute age actual breaking strength The breaking load obtained from a tensile test to destruction on a sample of rope. Hammond actual horsepower The horsepower really developed, as proved by trial. Standard, 2 44

actual performance curve A performance curve showing the results actually obtained from a coal preparation treatment. BS, 5 actuated roller switch A switch placed in contact with the belt conveyor immediately preceding the conveyor it is desired to control. In the centrifugal sequence control switch, a driving pulley bears against the driving belt; as the latter moves, the pulley rotates and the governor weights attached to the pulley shaft are flung out and so complete an electrical pilot circuit and thus start the subsidiary belt. Nelson acute bisectrix a. The line that bisects the acute angle of the optic axes of biaxial minerals. Fay b. The angle 2NaI+Na2 S4 O6 . Also called iodometry. Pryor, 3 iodine A nonmetallic, bluish-black, lustrous solid element, volatilizing at ordinary temperatures into a blue-violet gas with an irritating odor. Symbol, I. Occurs sparingly in sea water, in saltpeter and nitrate-bearing earth (known as caliche), in brines, and in brackish waters from oil and salt wells. Its compounds are used in medicines, photography, and organic chemistry. Handbook of Chemistry and Physics, 3 iodine pentoxide method Accurate determinations of very low concentrations of carbon monoxide are required of samples from pits troubled with spontaneous combustion and those in which diesel locomotives are operating. This method involves the passage of a known volume of the sample first through a train of reagents for purifying and drying and then through a heated tube of iodine pentoxide; if carbon monoxide is present, proportional amounts of iodine and carbon dioxide are formed, either of which may be determined. Sinclair, 1 iodine pentoxide test An iodine pentoxide (Hoolamite) test consists of a glass tube filled with a reagent mixed with fuming sulfuric acid and carried by crushed pumice through which a known volume 1637

of the air to be sampled is discharged from a rubber bulb after preliminary drying. The bulb is squeezed 10 times; the carbon monoxide present changes the color of the reagent from grey to green, and the concentration is obtained by reference to a color chart supplied with the instrument. The instrument reads down to about 0.07% carbon monoxide. Sinclair, 1 iodobromite See: iodembolite iodyrite See: iodargyrite iolite See: cordierite ion An atom or a group of atoms combined in a radical or molecule that carries a positive or a negative electric charge as a result of having lost or gained one or more electrons. It may exist in solution, usually in combination with molecules of the solvent, or out of solution; it may be formed during electrolysis and migrate to the electrode of opposite charge, or it may be formed in a gas and be capable of carrying an electric current through the gas. Webster 3rd ion exchange Reversible exchange of ions contained in a crystal for different ions in solution without destruction of crystal structure or disturbance of electrical neutrality. The process is accomplished by diffusion and occurs typically in crystals possessing one- or twodimensional channelways where ions are relatively weakly bonded. Also occurs in resins consisting of three-dimensional hydrocarbon networks to which many ionizable groups are attached. Syn: base exchange ion-exchange column A tube packed with particles or beads of resin chosen for their ability to capture specific ions from an aqueous solution as it passes through the column. ionic activity measurement

1638

Use of an electrode reversible to the ion under test to form a half cell. This is connected by a salt bridge to a reference electrode, and the resulting electromotive force is measured. Pryor, 3 ionic bond a. Electrostatic force holding ions together in a crystal. Hurlbut b. A chemical bond between atoms, one of which is an electron donor and the other is an electron acceptor. Gaudin, 2 ionic equilibrium The situation when, for a prescribed temperature, pressure, concentration of reactants, and pH, the rate of dissociation of molecules into ions is approx. in balance with that of their recombination. Pryor, 3 ionic migration Movement of a charged particle through an electrolyte toward an electrode of opposite charge sign. The losses in a neutral salt around two electrodes during the passage of electric current are in ratio to velocities of ions migrating from these electrodes. Ionic velocities are stated in centimeters per second for a potential gradient of 1 V/cm. Pryor, 3 ionic mobility Velocity in a dilute solution of an ion where the potential difference across this is 1 V/cm. For hydrogen ions, the velocity is 0.00326 cm/s. Pryor, 3 ionic transport number Fraction of total current carried by one ion during electrolysis (ion migration). Pryor, 3 ionite A term referring to two different materials found in the Ione Valley of northern California: (1) a clay mineral, possibly a variety of kaolinite, found as scales in the Ione sandstone formation, and (2) an impure fossil hydrocarbon found in lignite, which is brownish-yellow, dissolved by chloroform, and yields a brown, tarry oil on destructive distillation. ionization

1639

The process of adding electrons to, or knocking electrons from, atoms or molecules, thereby creating ions. High temperatures, electrical discharges, and nuclear radiation can cause ionization. Lyman ionization chamber An instrument that detects and measures ionizing radiation by observing the electrical current created when radiation ionizes gas in the chamber, making it a conductor of electricity. Lyman ionization constant The ratio of the product of the activities of the ions produced from a given substance to the activity of the undissociated molecules of that substance. See also: activity ionizing radiation Any radiation that directly or indirectly displaces electrons from the outer domains of atoms; e.g., alpha, beta, or gamma radiation. Lyman ionosphere The outer part of the Earth's atmosphere, beginning at an altitude of about 25 miles (40 km) and extending to the highest parts of the atmosphere: it contains several regions that consist of a series of constantly changing layers characterized by an appreciable electron and ion content. Webster 2nd ion sieve separation Separation of ions by filtering them through the intermediately sized lattice of a suitable aluminosilicate zeolite, chosen to permit passage only of undersized ions through its rigid structure. Pryor, 3 iozite See: wuestite iranite A triclinic mineral, Pb10 Cu(CrO4 )6 (SiO4 )2 (F,OH)2 ; forms a series with hemihedrite in which zinc substitutes for copper; at the Sebarz Mine, northeast of Anarak, Iran. iridescence

1640

The exhibition of interference colors from the surface or interior of a mineral, caused by light interference from thin films or layers of different refractive index. Labradorite and some other feldspars show it. The tarnish on the surface of coal, copper pyrites, etc., is sometimes iridescent. Adj. iridescent. iridic gold Said to be a native alloy of gold and iridium carrying 62.1% gold, 30.4% iridium, 3.8% platinum, and 2.1% silver. Hess iridioplatinum An alloy usually containing 90% or more of platinum. The remaining percentage is of iridium, which is necessary to produce an alloy sufficiently stiff for use in gem mountings. iridium a. An isometric mineral, native Ir ; Mohs hardness, 6 to 7; sp gr, 22.2 if pure; occurs native (>80% Ir) and alloyed with osmium (iridosmine) or platinum in mafic to ultramafic rocks and derived alluvial deposits; in rare arsenides and sulfides, such as irarsite (Ir,Ru,Rh,Pt)AsS , iridarsenite (Ir,Ru)As2 , and iridisite-beta (Ir,Cu)3 S8 ; placer deposits may include gold. b. The most corrosion-resistant metal known. Symbol, Ir. It is mainly used as a hardening agent for platinum. Handbook of Chemistry and Physics, 3 iridosmine A natural alloy of iridium and osmium, (Ir,Os). Analyses show 43% to 77% iridium, 17% to 49% osmium, and a little rhodium, ruthenium, platinum, iron, and copper. Rhombohedral. Syn: osmite iriginite A canary-yellow mineral, (UO2 )(Mo26+ O7 ).3H2 O ; luster, vitreous; uneven fracture; does not fluoresce. Syn: priguinite Irish coal Slate, shale, or rock loaded out from a colliery as coal. Pryor, 3 Irish dividend An assessment on mining stock. Fay iris quartz 1641

A transparent quartz crystal containing minute air-filled or liquid-filled internal cracks that produce iridescence by interference of light. The cracks may occur naturally or be caused artificially by heating and sudden cooling of the specimen. Syn: firestone; rainbow quartz. iron a. Iron-base materials not falling into the steel classifications. See also: gray cast iron; ingot iron; malleable cast iron; nodular cast iron; white cast iron; wrought iron. ASM, 1 b. Colloquially, all derrick and drilling equipment above the heads of the workers on the drill platform. Long c. Any ferrous metal tool or part that must be fished from a borehole. Also called junk. Long d. An isometric mineral, native alpha-Fe ; metallic steel gray to black; sp gr, 7.3 to 7.9. Occurs as grains in basalt in Disko Island, Greenland; in meteorites, and in placers on South Island, New Zealand; and in Oregon and British Columbia. Nickel is commonly reported in iron in quantities up to several percent; meteoric iron generally contains at least 5%, and up to 25% to 65%, nickel. Because of the instability of iron under oxidizing conditions and the abundance of oxygen in the Earth's crust and atmosphere, practically all terrestrial iron occurs in the divalent (ferrous) or trivalent (ferric) state combined with other metals and nonmetallic elements in silicates, oxides, sulfides, etc. e. Fourth most abundant element, by weight, making up the crust of the Earth. Symbol, Fe. The most common ore is hematite, Fe2 O3 , from which the metal is obtained by reduction with carbon. Iron is the cheapest and most abundant, useful, and important of all metals. Handbook of Chemistry and Physics, 3 iron alum See: halotrichite iron black Finely divided antimony. Standard, 2 iron clay See: clay ironstone iron formation A chemical sedimentary rock, typically thin-bedded and/or finely laminated, containing at least 15% iron of sedimentary origin, and commonly but not necessarily containing layers of chert. Various primary facies (usually not weathered) of iron formation are distinguished on the basis of whether the iron occurs predominantly as oxide, silicate, carbonate, or sulfide. Most iron formation is of Precambrian age. In mining usage, the term refers to a low-grade sedimentary iron ore with the iron mineral(s) segregated in 1642

bands or sheets irregularly mingled with chert or fine-grained quartz. CF: ironstone; jaspilite. Essentially synonymous terms are itabirite; banded hematite quartzite; taconite; quartz-banded ore; banded iron formation; calico rock; jasper bar. AGI iron froth A fine spongy variety of hematite. Fay iron furnace A furnace in which iron is smelted or worked in any way. Standard, 2 iron glance A variety of hematite; specular iron. See also: specularite iron hat a. See: gossan b. See: safety hat; hardhat. c. A weathered ironstone outcrop. Pryor, 3 iron hypersthene See: ferrosilite iron man a. An iron worker; a manufacturer of iron; esp. one engaged in the processing of iron. Webster 3rd b. A worker who weighs out ground iron ore and adds it to slurry or dryground rock as it goes into the cement kiln. Webster 3rd c. An apparatus on wheels for supporting a glassblower's pontil while blowing large cylinders, as for window glass. Standard, 2 ironmaster Person who conducts or manages the founding or manufacture of iron, esp. on a large scale. Webster 3rd iron mica A micaceous hematite. See: biotite iron molybdate See: ferrimolybdite 1643

iron monarch An important iron ore (chiefly hematite) deposit in the Middleback Ranges area of South Australia. Nelson iron olivine See: fayalite iron ore Ferruginous rock containing one or more minerals from which metallic iron may be profitably extracted. The chief ores of iron consist mainly of the oxides: hematite, Fe2 O3 ; goethite, alpha -FeO(OH); magnetite, Fe3 O4 ; and the carbonate, siderite or chalybite, FeCO3 . See also: bog iron ore; limonite; kidney iron ore; magnetite; siderite; hematite; prereduced iron-ore pellet. AGI iron oxide a. A common ore of iron, sometimes prepared as a fine powder for use by drillers as a drill-mud heavy loader. Long b. A common compound of iron and oxygen; e.g., rust. Long iron oxides The basic constituent of the ferromagnetic spinels or ferrites. FeO, Fe2 O3 , and Fe3 O4 have melting points ranging from that of FeO at 1,420 degrees C to that of Fe2 O3 at 1,565 degrees C. Used extensively for producing colors in glasses, glazes, and enamels. Iron and iron oxides produce brown or reddish colors in ceramic mixtures if they are fired in an oxidizing atmosphere, and greenish or bluish colors if fired in a reducing atmosphere. Iron oxides are fluxing and coloring materials. Larger particles produce brown or black spots, which, particularly in whiteware, are undesirable. Much care is taken to remove iron and iron oxides from the raw materials and from the bodies used for whiteware manufacture. Lee; Handbook of Chemistry and Physics, 2 iron pan A general terrm for a hardpan in a soil in which iron oxides are the principal cementing agents; several types of iron pans are found in dry and wet areas and in soils of widely varying textures. AGI iron phosphate See: vivianite 1644

iron piler A laborer who removes iron from cars, sometimes breaks it, and piles and classifies it according to grade. Fay iron portland cement Mixture of portland cement and granulated blast furnace slag. Bennett iron pyrite See: pyrite iron-reduction process A process used in the treatment of lead ores. See also: precipitation process iron refining The reduction of prepared ores of iron to metallic iron, as in the blast furnace. The reduction and purification of semirefined iron, such as pig iron, or a mixture of pig iron, scrap iron, and scrap steel, to form substantially pure iron or steel, as in the electric furnace, open- hearth furnace, puddling furnace, or Bessemer converter. Henderson iron runner The spout by which iron flows from the taphole of a blast furnace. Fay iron sampler In the iron and steel industry, a laborer who obtains samples of iron ore as it is brought into the plant, or samples of semifinished or finished metal products, such as iron and steel sheets, rails, rods, or bars, and carries them to the laboratory for routine tests. Also called sampler; test carrier. DOT iron sand A sand containing particles of iron ore (usually magnetite), as along a coastal area. AGI iron schefferite See: pyroxene iron series 1645

See: magnetite ironshot a. Said of a mineral that is streaked, speckled, or marked with iron or an iron ore. AGI b. Containing small nodules or oolitic bodies of limonite or hematite; e.g., an ironshot rock in which the ooliths are essentially composed of limonite. A limonitic oolith in an ironshot rock. AGI ironsmith A worker in iron, as a blacksmith. Standard, 2 iron spar See: siderite iron stain Strongly colored yellowish, reddish, or brownish deposit of iron oxides. Skow iron steel A material formed of iron between steel surfaces, or of steel-located iron. Standard, 2 ironstone Any rock containing a substantial proportion of an iron compound, or any iron ore from which the metal may be smelted commercially; specif., an iron-rich sedimentary rock, either deposited directly as a ferruginous sediment or resulting from chemical replacement. The term is customarily applied to a hard, coarsely banded or nonbanded, and noncherty sedimentary rock of post-Precambrian age, in contrast with iron formation. The iron minerals may be oxides (limonite, hematite, magnetite), carbonate (siderite), or silicate (chamosite); most ironstones containing iron oxides or chamosite are oolitic. See: clay ironstone; banded ironstone. CF: iron formation ironstone cap A surficial or near-surface sheet or cap of concretionary clay ironstone. AGI ironstone clay See: argillaceous hematite; red hematite. iron sulfides 1646

See: chalcopyrite; pyrite; marcasite; pyrrhotite. iron talc See: minnesotaite iron vitriol See: melanterite ironworker Person engaged in manufacturing iron or ironwork. Standard, 2 ironworks An establishment for the manufacture of iron or of heavy ironwork. Standard, 2 irradiation Exposure to radiation, as in a nuclear reactor. Lyman irregular polygon Polygon in which neither the sides nor the angles are equal. Jones, 2 irrespirable Not respirable; not fit to be breathed. Said of mine gases. Standard, 2; Fay irrespirable atmosphere In a coal mine, atmosphere containing poisonous gases or a lack of sufficient oxygen as a result of combustible gases explosions, coal-dust explosions, combined gas and dust explosions, or mine fires, and which can only be entered by persons wearing breathing apparatus. McAdam, 1 irrotational wave See: P wave; compressional wave. irruption A nearly obsolete syn. of intrusion. AGI 1647

isanomalic line Line of equal value of an anomaly. Schieferdecker Isbell table Obsolete type of shaking table. Pryor, 3 iserine See: ilmenorutile ishikawaite An orthorhombic mineral, (U,Fe,Y,Ca)(Nb,Ta)4 (?) ; opaque black; at Ishikawa, Iwaki Province, Japan. isinglass Transparent sheet mica, commonly muscovite, principally from pegmatite dikes. See also: mica; muscovite. island arc A group of islands having a curving, arclike pattern. Most island arcs lie near the continental masses, but inasmuch as they rise from the deep ocean floors, they are not a part of the continents proper. Stokes isoanthracite lines a. A term for lines of equal volatile content (now called isovols) drawn on a map or diagram. Tomkeieff b. Lines of equal C:H ratio in coal drawn on the map or diagram. Tomkeieff isobar An imaginary line or a line on a map or chart connecting or marking places on the surface of the Earth where the height of the barometer reduced to sea level is the same either at a given time or for a certain period. Webster 3rd isobase A term used for a line that connects all areas of equal uplift or depression; it is used esp. in Quaternary geology as a means for expressing crustal movements related to postglacial uplift. AGI 1648

isobath a. A line on a map or chart that connects points of equal water depth. Syn: bathymetric contour; depth contour. AGI b. An imaginary line on a land surface along which all points are the same vertical distance above the upper or lower surface of an aquifer or above the water table. AGI isocals Lines of equal calorific value in coal drawn on a map or diagram. Tomkeieff isocarb On a map or diagram, a line connecting points of equal fixed-carbon content in coal. See also: isocarbon map isocarbon map A map showing, by contours, the areas having an equal quantity of carbon within an assumed interval of stratigraphic section. See also: isocarb Ballard isochore a. A line drawn on a map through points of equal drilled thickness for a specified subsurface unit. Thickness figures are uncorrected for dip in vertical wells, and corrected for hole angle, but not for dip, in deviated wells. CF: isopach b. In a phase diagram, a line connecting points of constant volume. AGI isochore map A map showing drilled thickness of a given stratigraphic unit by means of isochores. Syn: convergence map isochromatic lines In stress analysis by the photoelastic method, lines of equal difference of principal stress, appearing as colored streaks. See also: photoelasticity. (Hammond, 1965) isochrome map A contour map that depicts the continuity and extent of color stains on geologic formations. AGI isochronal 1649

See: isochronous isochrone lines Lines connecting points of equal times. When the relative seismic velocities are known, the isochrones can be translated into depth contours. See also: refraction shooting isochronous a. Equal in duration or uniform in time; e.g., an isochronous interval between two synchronous surfaces, or an isochronous unit of rock representing the complete rock record of an isochronous interval. AGI b. A term frequently applied in the sense of synchronous, such as an isochronous surface having everywhere the same age or time value within a body of strata. Syn: isochronal isoclinal Adj. of isocline. AGI isoclinal fold A fold whose limbs are parallel. Syn: isocline isocline See: isoclinal fold isoclinic A line (in a stressed body) at all points on which the corresponding principal stresses have the same direction. Roark isoclinic line a. A line drawn through all points on the Earth's surface having the same magnetic inclination. The particular isoclinic line drawn through points of zero inclination is given the special name of aclinic line. Hunt b. An isomagnetic line connecting points of equal magnetic inclination. AGI isodesmic Characteristic of a crystal structure with bond strengths roughly equal in all directions. isodiametric 1650

Refers to the hexagonal, trigonal, and tetragonal crystal systems; i.e., having the lateral crystal axes a1 and a2 of equal length. CF: isometric; anisometric. isodimorphous In mineralogy, both isomorphous and dimorphous; said of certain groups of minerals. Fay isodynamic line Any line joining points of equal magnetic intensity. Applicable to the total intensity or the vertical, horizontal, north-south, or east-west components. So used in terrestrial magnetism literature, esp. in British and Canadian writings. AGI isoelectric point Zero potential or point of electrical neutrality; the hydrogen-ion exponent at which particles in aqueous suspension are neutral and best able to flocculate. Also called zero point of change. Pryor, 4 isofacial a. Pertaining to rocks belonging to the same metamorphic facies and having reached equilibrium under the same set of physical conditions. Syn: isograde b. Pertaining to rocks belonging to the same sedimentary facies; e.g., an isofacial line on a map, along which the thickness of stratum of the same lithologic composition is constant. AGI isogal In gravity prospecting, a contour line of equal gravity values. AGI isogam In magnetic prospecting, a contour line of equal magnetic values. AGI isogam map A chart showing contour lines of equal magnetic field intensity and employed in the magnetic methods of geophysical prospecting. Also called isogal map in gravity surveys. Nelson isogeotherm A line or surface within the Earth connecting points of equal temperature. Syn: isogeothermal line; geotherm; geoisotherm. AGI 1651

isogeothermal line See: isogeotherm isogon See: isogonic line isogonic line An isomagnetic line connecting points of equal magnetic declination. See also: agonic line isograd A line on a map joining points at which metamorphism proceeded at similar values of pressure and temperature as indicated by rocks belonging to the same metamorphic facies. Such a line represents the intersection of an inclined surface with the Earth's surface corresponding to the boundary between two contiguous facies or zones of metamorphic grade, as defined by the appearance of specific index minerals; e.g., garnet isograd, staurolite isograd. AGI isograde See: isofacial isogram A general term for a line on a map or chart connecting points having an equal numerical value of some physical quantity (such as temperature, pressure, or rainfall); an isopleth. AGI isohume A line constructed on a map, somewhat similar to a contour line, but connecting points of equal moisture content of coal in the bed. AGI isohyet A line connecting points of equal precipitation. AGI isolate A culture of an organism isolated by selection procedures. Rogoff 1652

isolated consignment A particular case of a single consignment where the sampling is to be carried out without prior knowledge of a coal's sampling characteristics other than its presumed ash content and size. Nelson isolator Part of a circuit that can be removed from it in order to break the circuit when there is no current flowing. Hammond isoline See: isopleth isolith a. An imaginary line connecting points of similar lithology and separating rocks of differing nature, such as of color, texture, or composition. AGI b. An imaginary line of equal aggregate thickness of a given lithologic facies or particular class of material within a formation, measured perpendicular to the bedding at selected points (which may be on outcrops or in the subsurface). AGI isolith map A map that depicts isoliths; esp. a facies map showing the net thickness of a single rock type or selected rock component in a given stratigraphic unit. AGI isomagnetic line A line connecting points of equal value of some magnetic element; e.g., isogonic line; isodynamic line; isoporic line. AGI isomer a. One of two or more substances composed of the same molecular formula, but differing in chemical or physical properties owing to the arrangement of the atoms in the molecule. Hess b. In nuclear science, one of two or more nuclides with the same numbers of neutrons and protons in the nucleus, but having different energy. Lyman isomeric Of, relating to, or exhibiting isomerism. Webster 3rd isometric 1653

a. A system of crystallization with three axes at right angles and of equal length; nine planes of symmetry; singly refracting. CF: anisodesmic b. Characterized by equality of measure. c. The crystal system characterized by three orthogonal axes of equal length. Syn: cubic; equant. CF: anisometric; isodiametric. isometric line See: isopleth isometric projection In technical drawing, a three-dimensional view of an object can be drawn to scale with three perpendicular edges at 120 degrees to each other, and with the vertical edges vertical. See also: oblique projection; axonometric projection. Hammond isomorphism The name given to chemical compounds that have analogous composition, similar crystal structures, and closely related crystal forms; e.g., carbonate minerals of the aragonite group--aragonite, witherite, strontianite, and cerrusite--in which the metal ions are different but the several minerals crystallize in the orthorhombic system in closely similar forms. Adj. isomorphous. Noun, isomorph. CF: polymorphism isomorphous Originally defined (Mitscherlich, 1819) as having similar crystalline form, but now generally restricted to compounds that form solid solutions by isomorphous substitution; i.e., by the replacement of one ion for another in a crystal structure without alteration in the crystal form. CF: isotypic isomorphous mixture a. A solid solution of two or more isomorphous substances. Fay b. A type of solid solution in which mineral compounds of analogous chemical composition and closely related crystal habit crystallize together in various proportions. CF: solid solution Harbison-Walker isomorphous replacement A characteristic of some minerals where substitution for one or more elements by others does not change the crystal structure. An example is the substitution of iron for zinc in sphalerite, wherein the iron content can range up to more than 15% without changing the sphalerite structure. Similarly, iron, manganese, and magnesium ions can replace each other in the calcite structure common to siderite, rhodochrosite, and magnesite. 1654

isomorphous series Descriptive of two minerals with the same crystal structure but different end-member compositions which may show partial or complete crystal miscibility (solid solution) between them. One mineral may belong to more than one isomorphous series; e.g., the garnet grossular forms a series with andradite, with hibschite and katoite, and with uvarovite. There are many isomorphous series among minerals; e.g., plagioclase feldspars, monoclinic pyroxenes, and the spinel and garnet groups. CF: solid solution isontic line See: isopleth isopach A line drawn on a map through points of equal true thickness of a designated stratigraphic unit or group of stratigraphic units. CF: isochore thickness contour. AGI isopach map A map indicating, usually by means of contour lines, the varying thickness of a designated stratigraphic unit. Also called isopachous map. AGI isopachous Of, relating to, or having an isopach; e.g., an isopachous contour. Not recommended usage. AGI isopachous line See: isopach isopachous map A nonrecommended syn. of isopach map. AGI isopachyte British term for isopach. AGI isophysical series A series comprising rocks of different chemical composition that were metamorphosed under identical physical conditions. 1655

isopic Said of sedimentary rocks of the same facies, or said of facies characterized by identical or closely similar rock types. The rocks may be formed in different sedimentation areas or at different times or both, but the lithologies are the same; e.g., a facies repeated in vertical succession. Also, said of a map depicting isopic facies or rocks. CF: heteropic isopical Relating to synchronous deposits that exhibit the same facies. isopiestic Constant value of pressure on a surface of the sea. Hy isopiestic line See: equipotential line isopleth a. In a strict sense, a line or surface on which some mathematical function has a constant value. It is sometimes distinguished from a contour by the fact that an isopleth need not refer to a directly measurable quantity characteristic of each point in the map area; e.g., maximum temperature of a particular point. AGI b. A general term for a line, on a map or chart, along which all points have a numerically specified constant or equal value of any given variable, element, or quantity (such as abundance or magnitude), with respect to space or time; esp. a contour. Etymol. Greek isos, equal, + plethos, fullness, quantity, multitude. Syn: isogram; isoline; isontic line; isometric line. AGI isopor See: isoporic line isoporic line A line drawn through points whose annual change in magnetic declination is equal. Syn: isopor isopycnic A line connecting points of equal density, particularly of ocean water. A line connecting points of equal atmospheric density may be called an isostere. Hunt isorads 1656

Lines joining points of equal radioactivity, drawn from geiger- or scintillation-counter data to form an isorad map. AGI isoresistivity plan A plan showing lines of equal resistivity at a certain selected depth. It is prepared from data obtained by the resistivity method of geophysical prospecting. Nelson isoseism See: isoseismal line isoseismal A line on the surface of the Earth joining points of equal seismic disturbance due to any single earthquake. Syn: isoseismal line AGI isoseismal line A line connecting points on the Earth's surface at which earthquake intensity is the same. It is usually a closed curve around the epicenter. Syn: isoseism; isoseismal. AGI isostannite See: kesterite isostasy The condition of equilibrium, comparable to floating, of the units of the lithosphere above the asthenosphere. Crustal loading, as by ice, water, sediments, or volcanic flows, leads to isostatic depression or downwarping; removal of load leads to isostatic uplift or upwarping. Two differing concepts of the mechanism of isostasy are the Airy hypothesis of constant density and the Pratt hypothesis of constant thickness. See also: isostatic compensation isostatic Subjected to equal pressure from every side; being in hydrostatic equilibrium; relating to or characterized by isostasy. See: stress trajectory isostatic adjustment See: isostatic compensation isostatic anomaly 1657

a. The difference between the observed value of gravity at a point after applying to it the isostatic correction and the normal value of gravity at the point. AGI b. Anomaly on a map of observed gravity anomalies after applying the isostatic correction. Negative isostatic anomalies indicate undercompensation, implying a tendency to rise; positive isostatic anomalies connote overcompensation and a tendency to sink. AGI c. A gravity anomaly calculated on a hypothesis that the gravitational effect of masses extending above sea level is approx. compensated by a deficiency of density of the material beneath those masses; the effect of deficiency of density in ocean waters is compensated by an excess of density in the material under the oceans. See also: anomaly isostatic compensation The adjustment of the lithosphere of the Earth to maintain equilibrium among units of varying mass and density; excess mass above is balanced by a deficit of density below, and vice versa. See also: isostasy Syn: isostatic adjustment; isostatic equilibrium. AGI isostatic correction The adjustment made to values of gravity, or to deflections of the vertical, observed at a point, to take account of the assumed mass deficiency under topographic features for which a topographic correction is also made. AGI isostatic equilibrium The shifting of the rock beneath the Earth's crust in response to the shifting in the weight above the Earth's crust. Syn: isostatic compensation isostructural a. Refers to minerals that are closely similar in crystallographic, physical, and chemical properties but have little tendency for isomorphous substitution; same as isotypic. AGI b. Said of minerals that have the same ionic or molecular crystal structure. Isostructure is more rigorous than isomorphism; the latter requires similar crystal forms, the former a one-to-one correspondence of atomic particles. Isostructural minerals may differ markedly in chemical composition and physical properties, e.g., fluorite and uraninite, or may be closely similar, e.g., the calcite group of carbonates. isotherm A line connecting points of equal temperature. Isotherm maps are often used to portray surface temperature patterns of water bodies. AGI isothermal

1658

a. A change taking place at a constant temperature. Strock, 2 b. Pertaining to the process of changing the thermodynamic state of a substance, such as its pressure and volume, while maintaining the temperature constant. AGI isothermal compression a. Reduction in the volume of a fluid without any change in its temperature. Standard, 2 b. Compression in which there is no change in the temperature of the air; used as a standard against which the conditions of actual compression may be checked. Lewis isothermal expansion The expansion of air under constant temperature. Since the air does work on expanding, it loses heat; consequently, heat must be added to the air to maintain it at constant temperature. Lewis isothermal layer A water column through which a constant temperature exists. Hy isothrausmatic A descriptive term applied to igneous rocks with an orbicular texture in which the nuclei of the orbicules are composed of the same rock as the groundmass. CF: crystallothrausmatic; homeothrausmatic; heterothrausmatic. AGI isotropic Said of a medium with properties the same in all directions; in crystal optics, said of a crystal with refractive index that does not vary with crystallographic direction. Isometric crystals and amorphous substances, such as glass, are generally isotropic. Noun, isotropy. CF: uniaxial; anisotropic. isotropic mass A mass having the same property (or properties) in all directions. ASCE isotropy a. The condition of having properties that are uniform in all directions. Adj. isotropic. CF: uniaxial b. Refers to matter with properties the same in all directions; in optics, a crystal with an index of refraction that does not vary with crystallographic direction. Isometric crystals and amorphous substances, e.g., glass, are generally isotropic. CF: anisotropy 1659

isotypic Having analogous composition and closely similar crystal structure, but not capable of intercrystallizing to form solid solutions. Examples are calcite and soda niter; galena and NaBr. CF: isomorphous isotypy One-dimensional polymorphism; e.g., alternate stacking of identical layers of micas or clays. Also called isotypism. CF: polymorphism isovelocity The phenomenon of sound being the same in all parts of a given water column. Hy isovol Lines constructed on a map of a coalbed connecting points of equal volatile matter, delineating the distribution of volatile matter of the coal. AGI Istrian stone A marble found near Trieste, from which Venice is largely built. Fay itabirite A laminated, metamorphosed oxide-facies iron formation in which (1) the original chert or jasper bands have been recrystallized into megascopically distinguishable grains of quartz and (2) the iron is present as thin layers of hematite, magnetite, or martite (Dorr & Barbosa, 1963). The term was originally applied in Itabira, Brazil, to a high-grade, massive specular-hematite ore (66% iron) associated with a schistose rock composed of granular quartz and scaly hematite. The term is now widely used outside Brazil. CF: jacutinga; canga. Syn: banded-quartz hematite; hematite schist. AGI itacolumite A micaceous sandstone or a schistose quartzite that contains interstitial, loosely interlocking grains of mica, chlorite, and talc; exhibits flexibility when split into thin slabs. Type locality is Itacolumi Mountain in Minas Gerais, Brazil. Syn: flexible sandstone; articulite. AGI Italian asbestos A name often given to tremolite asbestos to distinguish it from Canadian or chrysotile asbestos; extensively quarried in Piedmont and Lombardy, Italy. CMD 1660

ivory The fine-grained, calcareous creamy-white dentine forming most of the tusks of elephants and the teeth or tusks of certain other large animals, such as the walrus; it has long been esteemed for a wide variety of ornamental articles. Elephant ivory is now illegal to use. It is often simulated by bone. ivory turquoise Odontolite; fossil tooth or bone colored by a blue phosphate of iron. Syn: bone turquoise Iwan-pattern earth auger A dry sampler equipped with an Iwan auger shoe or cutterhead. See: post-hole digger Ixiolite A monoclinic mineral (Ta,Nb,Sn,Fe,Mn)4 O8 ) .

J jacinth See: essonite; hyacinth; zircon. jack a. A name for zinc ore; blackjack. See: sphalerite b. Cannel coal interstratified with shale. c. Coaly shale, commonly canneloid. d. To drill a rock by hand, using a 4-lb (1.8-kg) hammer in one hand and a steel drill in the other ("single jacking"). "Double jacking" is to use a two-handed (sledge) hammer with the steel drill held by another worker. e. A portable device used for exerting great pressure or for lifting a heavy body through a small distance. Syn: anchor jack jack boom a. A boom that supports sheaves between the hoist drum and the main boom in a pull shovel or a dredge. Nichols, 1 b. A boom whose function is to support sheaves that carry lines to a working boom. Nichols, 1 jack catch Safety catch in the rail track to stop tubs running back on inclines. Mason 1661

jack engine Eng. A donkey engine; a small engine employed in sinking a shallow shaft. Fay jacket An outer casing or cover constructed around a cylinder or pipe, the annular space being filled with a fluid for either cooling, heating, or maintaining the cylinder contents at constant temperature; e.g., the water jackets of an internal combustion engine. CTD jacket set a. Set of timbers used in a shaft outside the regular shaft set, as extra protection in heavy ground. Pryor, 3 b. Set like the larger shaft set with dividers omitted, except that the wall and end plates are broken at all joints to facilitate renewing. Used in heavy ground to protect the regular shaft timbers. The jacket set is placed outside the regular timbers, separated from them by short blocks, and is blocked and wedged against the rock. Lewis jackhammer A percussive type of automatically rotated rock drill that is worked by compressed air. It is light enough to be used without a tripod and to be hand held. Pryor, 3 jackhead See: delivery drift jackhead pit a. A small pit without hoisting appliances, frequently serving as a ventilation shaft. Standard, 2 b. A small shaft sunk within a mine. A winze. Fay jackhead pump A subordinate pump in the bottom of a shaft, worked by an attachment to the main pump rod. Fay jackhead set Newc. The set of pumps in the jackhead staple. Fay jackhead staple Eng. A small mine for the supply of coal for the boilers. Fay 1662

jack hole Eng. In coal mining, a bolthole. See also: cut-through Standard, 2; Fay jacking pressure The amount of pressure exerted by a jack to force a cone penetrometer into a soil being tested. Long jacking up The raising up of masses of machinery and heavy structures by means of jacks. Crispin jackknife The collapse of a drill tripod or derrick. Long jackknife rig A truck-mounted diamond or small rotary drill equipped with a hinged derrick. Long jackknifing A collapsing of square-set timbers by wall pressure or through poor placement. Fay jackleg a. Light supporting bar for use with a jackhammer. Pryor, 3 b. An outrigger post. Nichols, 1 jackpipe A hollow iron pipe large enough to slip over the end of the front jack of a cutting machine to make it hold more firmly against the coal. Fay jack pit N. of Eng. A shallow shaft in a mine communicating with an overcast. See also: jackshaft; overcast. Syn: jacky pit jack post This timber is used where the coal seam is separated by a rock band and one bench is loaded out before the other. If the top bench is worked off first, the jack posts are set between the bottom bench of the coal and the roof. If the bottom bench is cleaned up 1663

first, the jack posts are set between the bottom and the top bench. At least two jack posts should be used and as many more as is necessary to keep the top bench of coal or the roof from coming down while the coal is being loaded out. Kentucky jackroll A windlass worked by hand. Fay jackscrew a. A jack in which a screw is used for lifting or exerting pressure; also, the helical-screw part of a jackscrew. Syn: screwjack b. A heavy screw set in the base or frame of a drill machine for the purpose of leveling the drill. Long jack setter A miner who assists in the operation of an auger-type underground mining machine; duties include seeing that the roof of the mine at or near the machine is in a safe condition. See also: machine helper Fay; DOT jackshaft An intermediate driving shaft. See also: jack pit jacky pit See: jack pit jacobsite An isometric mineral, 8[MnFe2 O4 ] ; spinel group; occurs with manganese ores. Jacobs process A method in which bauxite is fused in an electric furnace to form a synthetic corundum. Jacob staff A straight rod or staff pointed and shod with iron at the bottom for insertion in the ground, having a socket joint at the top, and used instead of a tripod for supporting a compass. Webster 3rd Jacquet's method

1664

Use of electrolytic polishing to complete the finish on metal surfaces. After mechanical polishing they are made the anodes in a suitable electrolyte. Pryor, 3 jacupirangite An ultramafic plutonic rock that is part of the ijolite series; composed chiefly of titanaugite and magnetite, with a smaller amount of nepheline; a nepheline-bearing clinopyroxenite. Its name, given by Derby in 1891, is derived from Jacupiranga, Brazil. AGI jacutinga A term used in Brazil for disaggregated, powdery itabirite, and for variegated thinbedded, high-grade hematite iron ores associated with and often forming the matrix of gold ore. Etymol. from its resemblance to the colors of the plumage of Pipile jacutinga, a Brazilian bird. CF: itabirite jad a. Som. A long and deep holing, cutting, or jud, made for the purpose of detaching large blocks of stone from their natural beds. b. Prov. Eng. To undercut (coal or rock). Standard, 2 jade A microcrystalline gem variety of jadeite or nephrite (actinolite) with a toughness (resistance to breakage) exceeded only by that of carbonado diamond; ranges from nearly white to emerald-green, the latter being the most valuable; finest quality is reported to come from northern Burma (Myanmar) and the Yunnan Province of south China. The emerald-green color is attributed to jadeite and to trace amounts of chromium. There are many imitations of jade, including green-dyed onyx (Mexican jade), aventurine quartz containing fuchsite mica (Indian jade), vesuvianite (California jade), green hydrogrossular from South Africa, green organic or inorganic dyes or substitutes inserted under white jade, glass, dyed quartz, and bowenite or williamsite varieties of serpentine. "Jade cat's-eye" is a contradiction in terms. See: jadeite; nephrite; toughness. jadeite A monoclinic mineral, 4[NaAlSi2 O6 ] ; pyroxene group; apple green to emerald green, white, lavender, tomato red, or brown; tough; associated with albite from high-pressure, low-temperature metamorphosed plagioclase; an ornamental stone called "jade" (along with nephrite). jadeitite 1665

A metamorphic rock consisting principally of jadeite, commonly associated with small amounts of feldspar or feldspathoids. It is probably derived from an alkali-rich igneous rock by high-pressure metamorphism. AGI jadeolite A deep-green chromiferous syenite cut as a gemstone and resembling jade in appearance. Obsolete. AGI jag bolt An anchor bolt with a barbed flaring shank, which resists retraction when leaded into stone or set in concrete. Also called hacked bolt; rag bolt. Webster 3rd jager A bluish-white diamond of modern cut. Schaller jagging board An inclined board on which ore slimes are washed, as in a buddle. Standard, 2 jagoite A trigonal mineral, Pb3 FeSi4 O12 (Cl,OH) ; in yellow-green micaceous plates associated with another lead-iron silicate (melanotekite) in iron ore at Laangban, Sweden. jailer Som. A small tub or box in which water is carried in a mine. jalpaite A tetragonal mineral, Ag3 CuS2 ; forms intergrowths with argentite in the Black Hawk District, Grant County, NM. jam The blocking of a core barrel or core bit with core, sometimes deliberately. Long jamb a. A vein or bed of earth or stone, that prevents miners from following a vein of ore; a large block. Fay b. A projecting columnar part (as of a masonry wall) or mass (as of ore). Webster 3rd c. A vertical structural member forming the side of an opening in a 1666

furnace wall. Harbison-Walker d. A type of brick shape intended for use in the sides of wall openings. Harbison-Walker e. Sidewall of port of furnace superstructure carrying port crown load. ASTM jamb cutter In the coke products industry, a laborer who chips carbon and mud from the edges of coke-oven doors with a steel bar prior to the discharge of the coke. DOT jamb stick See: gim peg jamb wall See: breast wall James jig Movable sieve box supported on a rubber diaphragm and jigged mechanically up and down. Pryor, 3 jamesonite A monoclinic mineral, 2[Pb4 FeSb6 S14 ] ; metallic gray to black; in acicular crystals or capillary forms of featherlike appearance, thus the term "feather ore;" in low- to medium-temperature veins with other lead sulfosalts, galena, and carbonates. Syn: wolfsbergite; feather ore. James table Shaking table used in concentration of ground ores by gravity. Pryor, 3 jam out S. Staff. To cut or knock away the coal between holes. Fay jam riveter A riveting hammer provided with an air-operated telescopic casing to hold the hammer against the work. Hammond jar

1667

a. An appliance to permit relative movement between the rope and rods in a cable drill. It reduces shocks and the risk of rod or chisel breakages. See also: free-falling device b. To loosen or free stuck drill-stem equipment or tools by impacts delivered by quick, sharp, upward-traveling blows delivered by a drive hammer or jars. Long jar collar A swell coupling, attached to the upper exposed end of a drill rod or casing string, to act as an anvil against which the impact blows of a drive hammer are delivered and transmitted to the rod or casing string; also, sometimes used as a syn. for drive hammer. Also called drive collar; jar head. Syn: bell jar jargon A colorless, yellow, or smoky gem variety of zircon. jarlite A monoclinic mineral, NaSr3 Al3 (F,OH)16 ; in brownish crystals and spherulites at Ivigtut, Greenland. jar mill a. A small batch mill of ceramic material used in ore-testing laboratories in investigation of grinding problems. Pryor, 3 b. Any of the stoneware-lined pebble mills used in milling enamels on a small scale. Enam. Dict. c. See: ball mill Jarno taper This taper of 0.6 in/ft (4.2 cm/m) is used by a number of manufacturers for taper pins, sockets, and shanks used on machine tools. Crispin jarosite A trigonal mineral, KFe3 (SO4 )2 (OH)6 ; alunite group; amber yellow to dark brown; forms druses of minute crystals, crusts, and coatings; may be fibrous or fine-grained and massive; associated with volcanic rocks; thought to form under solfataric conditions at elevated temperatures and pressures; in some places with alunite; at many localities in the Western United States, Bolivia, Europe, and Russia. See also: cuprojarosite; kirovite. jaspagate See: agate jasper jasper 1668

A red variety of chalcedony. See also: chert; chalcedony. Syn: jasperite jasper bar See: jaspilite jasperine Banded jasper of varying colors. jasperite See: jasper jasperization The conversion or alteration of igneous or sedimentary rocks into banded rocks like jaspilite by metasomatic introduction of iron oxides and cryptocrystalline silica. See also: jaspilite jasperoid a. A dense, usually gray, chertlike siliceous rock, in which chalcedony or cryptocrystalline quartz has replaced the carbonate minerals of limestone or dolomite; a silicified limestone. It typically develops as the gangue of metasomatic sulfide deposits of the lead-zinc type, such as those of Missouri, Oklahoma, and Kansas. AGI b. Resembling jasper. AGI jasper opal An almost opaque common opal; commonly yellow-brown, reddish brown to red owing to iron oxides; resembles opal but has the luster of common opal. Also called jaspopal. jaspidean Resembling or containing jasper; jaspery. AGI jaspilite Interbedded jasper and iron oxides. CF: iron formation Syn: jasper bar jasponyx An opaque onyx, part or all of whose bands consist of jasper. 1669

jaw a. In a crusher, one of a pair of nearly flat or ribbed faces separated by a wedge-shaped opening. Nichols, 1 b. One or a set of two or more serrate-faced members between which an object may be grasped and held firmly, as in a vise, drill chuck, foot clamp, or pipe wrench. Long c. In a clutch, one of a pair of toothed rings, the teeth of which face each other. Nichols, 1 jaw breaker See: jaw crusher jaw crusher a. A primary crusher designed to reduce large rocks or ores to sizes capable of being handled by any of the secondary crushers. Enam. Dict. b. A crushing machine consisting of a moving jaw, hinged at one end, which swings toward and away from a stationary jaw in a regular oscillatory cycle. ACSG, 2 c. A machine for reducing the size of materials by impact or crushing between a fixed plate and an oscillating plate, or between two oscillating plates, forming a tapered jaw. Syn: jaw breaker jedding ax A stonecutter's ax with a flat face and a pointed peen. Webster 3rd jeffersite A kind of vermiculite from West Chester, Chester County, PA. Fay jeffersonite A variety of monoclinic pyroxene, commonly augite or diopside, containing manganese and zinc; forms large, coarse crystals having rounded edges and uneven faces; at Franklin, NJ. Jeffrey crusher Crusher used to break softish materials; e.g., limestone and coal. See also: swinghammer crusher Jeffrey diaphragm jig A plunger-type jig with the plunger beneath the screen. May be either single or multiple compartments. Its distinguishing features are (1) the stroke is produced with a cam operated by a lever and rocker-arm mechanism, (2) the weight of the column of water 1670

above the plunger is balanced by means of compressed air, (3) automatic operation is obtained by means of a submerged float that measures the specific gravity of the mass of coal, refuse, and water at the peak of the pulsion stroke, (4) refuse is withdrawn through a star gate extending the full width of the overflow lip, and (5) the slope of the screen plate is readily adjustable by means of heavy screws at the feed end. It is widely used on bituminous coal on sizes ranging up to a maximum of 6 in (15 cm). Mitchell Jeffrey molveyor An arrangement to keep a continuous miner in full operation at all times. It consists of a series of short conveyors, each mounted on driven wheels and coupled into a train to run alongside the heading or room conveyor. Nelson Jeffrey-Robinson cone A cone for coal washing; similar to the Callow and Caldecott cones. See also: cone classifier Jeffrey single-roll crusher A simple type of crusher for coal, with a drum to which are bolted toothed segments designed to grip the coal, forcing it down into the crushing opening. Jeffrey swing-hammer crusher A crusher enclosed in an iron casing in which a revolving shaft carries swinging arms having a free arc movement of 120 degrees . The rotation of the driving shaft causes the arms to swing out and strike the coal, ore, or other material, which, when sufficiently fine, passes through the grated bottom. Liddell Jeffrey-Traylor vibrating feeder A feed chute vibrated electromagnetically in a direction oblique to its surface. Rate of movement of material depends on amplitude and frequency of vibration. Jeffrey-Traylor vibrating screen An electric vibrating screen operated by action on an oscillating armature and a stationary coil. Gaudin, 1 jelly See: carbohumin; vegetable jelly. jenkin 1671

a. A drivage at right angles to the main cleat. Mason b. Eng. A road driven bordways in a pillar of coal. A jud driven bordways along a pillar of coal with goaf or an old bord on one side is called a "loose end jenkin." SMRB c. N. of Eng. A variation of "junking." Fay jenkinsite A ferroan variety of antigorite. Jeppe's tables A series of tables esp. compiled for mining work that includes tables of density, vapor pressure, and absolute humidity. Roberts, 1 Jeppestown shales S. Afr. Part of the Jeppestown Series forming the footwall of the Main Reef on the Central and East Rand. Beerman jerking table See: shaking table jerry man An employee in a mine whose duty it is to clean up falls or refuse, or to make a miner's working place safe. See also: wasteman Jersey fire clay brick A highly siliceous clay brick, semisilica brick. AISI jeso Beds of decomposed gypsum. Standard, 2 jet a. A hard black variety of cannel coal or brown coal, compact in texture, having a rough fracture and dull luster that takes a good polish and is thus used in the jewelry trade. Syn: black amber b. A sudden and forceful rush or gush of fluid through a narrow or restricted opening; e.g., a stream of water or air used to flush cuttings from a borehole. AGI c. A black variety of marble. d. Jet piercing, a thermal method of drilling large-diameter blast holes in hard cherty iron formation (taconite); formerly used mainly on the Mesabi Range in Minnesota, but also on the Marquette Range in Michigan. The rotating drill 1672

head is fed a mixture of kerosene and oxygen, ignited to direct a high-temperature flame against the rock, causing the rock to spall into fine particles by thermal expansion. Method has been almost totally replaced by rotary drills using tricone bits. See also: jet hole jetair flotation machine A multiple-cell machine of the mechanical agitation type. jet-assisted cutting a. Cutting rock by the very high force of a water jet against the ore so that the material could be processed for mineral recovery. SME, 1 b. Penetration of high-pressure water into material cracks such that the cracks between the grains are propagated and cutting occurs. See also: hydraulic mining jet coal See: cannel coal jet corer Consists of a length of pipe that is lowered from a vessel to obtain samples. Highvelocity water is pumped through the pipe, and the jetting action of this water issuing from the lower end of the pipe very effectively cuts a hole in the unconsolidated overburden sediments. Once at bedrock, the pipe is rammed into the rock with sufficient force to obtain a plug several inches in length. Mero jet drilling Piercing of rock strata by use of high-temperature flame to fuse the rock, together with jets of water to cause decrepitation and to flush the fragments out. Pryor, 3 jet grinding mill Enclosed chamber of relatively small cross section in which gas, at substantially high atmospheric pressures, is circulated at high speed, 400 to 700 ft/s (120 to 210 m/s). jet hole a. A borehole drilled by use of a directed, forceful stream of fluid or air. See also: jet b. A small hole in a nozzle. See also: jet jet hydraulic 1673

Stream of water used in alluvial mining. Pryor, 3 jet impact mill See: fluid energy mill jetloader A powder loader for loading horizontal drill holes with a diameter of more than 2 in (5.1 cm). It is intended for AN-prills and oil, and is also employed to blow sand into the holes for stemming. Langefors jet mill Differs from other mills in that the material is not ground against a hard surface. Instead, a gaseous medium is introduced. The gas may convey the feed material at high velocity in opposing streams or it may move the material around the periphery of the grinding and classifying chamber. The high turbulence causes the particles and feed material to collide and grind upon themselves. Cote jet mixer An apparatus that utilizes the mixing action of a water stream jetted into dry drill-mud ingredients to form a mud-laden fluid. CF: atomizer Long jetonized wood A name given to vitrain lamellae in coal. Synonymous with vitrain. Tomkeieff; AGI jet piercing The use of high-velocity jet flames to drill holes in hard rocks, as taconite, and to cut channels in granite quarries. It involves combustion of oxygen and a fuel oil fed under pressure through a nozzle to produce a jet flame generating a temperature above 2,600 degrees C. A stream of water joins the flame, and the combined effect is a thermodynamic spalling and disintegration of the rock into fragments that are blown from the hole or cut. Syn: thermic drilling jet-piercing drill See: fusion-piercing drill jet pump

1674

Consists of a centrifugal pump and motor at the ground surface and a jet down in the well below the water level, discharging at high velocity through a contracted section into the lift pipe. The centrifugal pump has two discharge pipes; one leads down to the jet, the other carries the water into the distribution system or into a storage tank. Syn: jet impact mill jet rock a. A coallike shale containing jet. Standard, 2 b. See: jet shale jet shale Bituminous shale containing jet. See also: jet jetstone A term for black tourmaline (schorl) in New South Wales, Australia. jetters Corn. The horizontal rods or poles connecting the water wheel and the pumps. jetting The process of sinking a borehole, or of flushing cuttings or loosely consolidated materials from a borehole, by using a directed, forceful stream (jet) of drilling mud, air, or water. AGI jetting drill A percussive drill for prospecting through superficial deposits. The drill is given a short stroke, 10 to 20 cm, and rotated by hand. Water is pumped down through the hollow steel rods and escapes through openings in the chopping bit. Casing is used, and the drilling rate is from 6 to 12 m per shift. Nelson jetting pump A water pump that develops very high discharge pressure. Nichols, 1 jetty a. An engineering structure (such as a breakwater, groin, seawall, or small pier) extending out from the shore into a body of water, designed to direct and confine the current or tide, to protect a harbor, or to prevent shoaling of a navigable passage by littoral materials. Jetties are often built in pairs on either side of a harbor entrance or at 1675

the mouth of a river. AGI b. A British term for a landing wharf or pier used as a berthing place for vessels. AGI jeweler's shop a. Corn. Miner's expression for a rich section of ore. Pryor, 3 b. Aust. A very rich patch of gold in either a reef or an alluvial formation. jews' tin Ancient slabs of tin found in Cornwall, England; so called from the belief that they were made by Jewish merchants and miners from Asia Minor before the present era of mining. Hess jib The lifting arm of a crane or derrick having a pulley at its outer end over which the hoisting rope passes. See also: front-end equipment Hammond jibbing-in The operation of gradually working the jib of a shortwall coal cutter into the cutting position in the coal seam. Jibbing-in is the first operation before starting the cutting run across the face. Syn: sumping-in Nelson jib crane A crane having a swinging boom or jib. Crispin jib end In conveyor systems, the delivery end when a jib is fitted to deliver the load in advance of and remote from the drive. Nelson jib holeman A person whose work is to make recesses for the cutting disk at the end of coal-cutting machine faces. CTD jib in The process of starting a cut by swinging the jib of the coal cutter (while the chain is cutting) from the front of the face to the full cutting position. See: sump jig 1676

a. A device that separates coal or ore from foreign matter, by means of their difference in specific gravity, in a pulsating water medium. Also spelled gig. See also: Baum jig; Bendelari jig; conset jig; Denver jig; Harz jig; hutch; jigger; jig washer; Pan-American jig; stripping a jig. b. A link or coupling connecting mine wagons. jig bed The agent used in a jig that consists of the heavy fractions in the coal that behave in some respects like a dense fluid. The pulsation of the water or the motion of the screen keeps the bed open or in suspension during part of the cycle so that heavy minerals entering the jig can settle into the bed. Lighter materials cannot penetrate the jig bed and therefore are forced to remain in the upper part of the jig and eventually discharge over the top. Other agents in use are lead shot, iron punchings, iron shot, pyrite, and magnetite. Newton, 1 jig brow Self-acting inclined track used to lower filled coal tubs and raise empty ones. Pryor, 3 jig bushing Hardened-steel bushing inserted in the face of a jig to serve as a guide for drills. Crispin jig chain S. Staff. A chain hooked to the back of a skip and running around a post to prevent its too rapid descent on an inclined plane. CF: snub Fay jig dips N. Staff. See: crossgate jigger a. See: pan conveyor; shaker conveyor; jigging conveyor. b. Scot. An apparatus for attaching hutches to a haulage rope. Fay c. A mechanism that operates with quick upand-down motion; a jolting device. See also: jig d. A machine for dressing small ore in which a sieve is dipped or moved about under water. e. Leic. A coupling hook used between coal cars. Standard, 2 f. Person that concentrates ore by jigging. Webster 3rd jigger work Eng. Dressed or partly dressed ore obtained from jigging. jigging 1677

a. The separation of the heavy fractions of an ore from the light fractions by means of a jig. b. Up-and-down motion of a mass of particles in water by means of pulsion. Pryor, 4 c. See: skimping jigging conveyor A series of steel troughs suspended from roof of stope or laid on rollers on its floor and given reciprocating motion mechanically to move mineral. Syn: jigger; pan conveyor. Pryor, 3 jigging machine A machine to jig ore. See also: jig jigging screen A screen or pair of screens to which a combined horizontal and vertical motion is imparted, normally by a crankshaft and connecting rod, the screen decks being horizontal or inclined at a small angle. See also: shaking screen jiggling in A technique for transferring a surface survey down a mine shaft in such a manner as to tie it in to an underground mine survey. See also: coplaning jig haulage See: gravity haulage jig indicator An apparatus resembling a steam engine indicator; used for drawing curved lines illustrating the action of jigs in ore beneficiation. Webster 2nd jig pin A pin used to prevent the turning of the turn beams. Standard, 2 jig washer A coal or mineral washer for relatively coarse material. The broken ore, supported on a screen, is pulsed vertically in water; the heavy (valuable) portion passes through the screen into a conical receptacle (hutch), and the gangue goes over the side. In coal washing, the heavy (worthless) shale passes downwards, and the lighter coal remains on top. See also: plunger jig washer; jig. Nelson 1678

jimboite An orthorhombic mineral, Mn3 B2 O6 ; the manganese analog of kotoite; with other manganese minerals at the Kaso Mine, Kanuma, Tochigi Prefecture, Japan. Jim Crow A portable hand-operated appliance for bending or curving rails. It incorporates a strong buttress screw thread. Nelson jinny road Underground gravity plane. Pryor, 3 jitty Leic. A short heading along which empties, horses, or workers travel. Fay joaquinite A monoclinic mineral, Ba2 NaCe2 Fe(Ti,Nb)2 Si8 O26 (OH,F).H2 O ; dimorphous with orthojoaquinite; forms minute honey-colored crystals; with benitoite and neptunite in San Benito County, CA. jock Scot. An iron rod, usually pronged, attached to the rear end of a train of hutches or cars being drawn up an incline; used to stop their descent in the event of the rope breaking. Fay jockey a. Aust. A Y-shaped grip placed in sockets at the end of a skip. The endless rope rests on this when used above the skip. Fay b. Mid. A self-acting apparatus on the front of a car, for releasing it from the hauling rope at a certain point. Fay joggle a. A joint of trusses or sets of timber for receiving pressure at right angles or nearly so. Zern b. Notches cut in round timbers set above other round pieces in underground timbering. Pryor, 3 c. An offset in a flat plane consisting of two parallel bends in opposite directions by the same angle. ASM, 1 d. A slight step-shaped offset formed into a flat piece of metal (as for providing a flange). Webster 3rd johachidolite 1679

An orthorhombic mineral, CaAlB3 O7 ; forms transparent grains and lamellar masses; fluoresces an intense blue owing to traces of rare-earth elements; in nepheline dikes, cutting sandstone in the Johachido District, Kenkyohokuco Prefecture, Korea. johannite A triclinic mineral, [Cu(UO2 )2 (SO4 )2 (OH)2 .8H2 O] ; radioactive; forms soft, bittertasting crystals that are polysynthetically twinned in two directions; in druses and reniform masses; at Joachimsthal, Czech Republic, and Gilpin County, CO; associated with gypsum. johannsenite A monoclinic mineral, 4[CaMnSi2 O6 ] ; pyroxene group; forms series with diopside and hedenbergite; shows clove-brown to grayish-green columnar, radiating, and spherulitic aggregates of fibers and prisms with black tarnish; in metasomatized limestones with manganese ore. Occurs at Puebla and Hildago, Mexico; Lane County, OR; Franklin, NJ; and Schio, Venetia, Italy. Johannsen number A number, composed of three or four digits, that defines the position of an igneous rock in Johannsen's classification. The first digit represents the class, the second the order, and the third and fourth the family. CF: Johannsen's classification Johannsen's classification A quantitative mineralogic classification of igneous rocks developed by the petrographer Albert Johannsen (1939). CF: Johannsen number AGI John Odges See: gun Johnson concentrator A cylindrical shell lined with grooved rubber set parallel to its axis, which is inclined, peripheral riffles thus being formed. Used to arrest heavy particles such as metallic gold as auriferous pulp flows gently through while the cylinder revolves slowly and the arrested material rises and drops on to a separate discharge launder. Pryor, 3 Johnston vanner Modified form of Frue vanner. Pryor, 3 1680

johnstrupite See: rinkite joint a. A divisional plane or surface that divides a rock and along which there has been no visible movement parallel to the plane or surface. Ballard b. A standard length of drill rod, casing, or pipe equipped with threaded ends by which two or more pieces may be coupled together; also, two or more standard lengths of drill rods or pipe coupled together and handled as a single piece in round trips. Long c. A fracture or parting that cuts through and abruptly interrupts the physical continuity of a rock mass. Not to be confused with bedding or cleavage. Long d. A line of cleavage in a coal seam. Syn: heading seam See also: joint plane joint box A cast iron box surrounding an electric cable joint, often filled with insulation after the joint between cables has been made. Hammond jointing a. In quarrying, the process of cutting to specified sizes and shapes, with smooth unchipped edges. AIME, 1 b. The condition or presence of joints in a body of rock. AGI jointing sleeves Insulating thimbles placed over the connected ends of detonator leads coupled in large rounds of shots, and also over the connections between the detonator leads and the shotfiring cable. BS, 12 joint line A visible line on imperfect glassware reproducing the line between separate parts of the mold in which the glass was made. Also called parting line; match mark; miter seam; mold mark; mold seam. Syn: seam Dodd joint plane A plane along a joint fracture or parting. Not to be confused with bedding and/or cleavage. See also: joint joint rose A rose diagram that shows the azimuth and intensity of jointing in an area. 1681

joints Natural cracks or fractures in rocks. They tend to occur in more or less parallel systems, and when quarry walls are maintained parallel and at right angles to them, they may be utilized as natural partings in the process of block removal. AIME, 1 joint set A group of more or less parallel joints. Billings joint system Consists of two or more joint sets or any group of joints with a characteristic pattern, such as a radiating pattern and a concentric pattern. Billings jointy Full of joints; specif. in mining, full of minute cracks or crevices, as rock. Standard, 2 Jolly balance a. A spring balance used to measure specific gravity of mineral specimens by weighing a specimen both in the air and immersed in a liquid of known density. McGraw-Hill, 1 b. A spiral-spring balance with two specimen pans, one for measuring weight in air and one for weight in water, used to determine specific gravity. CF: Westphal balance Jominy test A hardenability test in which a standard test piece, 4 in (10.2 cm) long and 1 in (2.54 cm) in diameter, is heated to a predetermined temperature, rapidly transferred to a jig fixture, and quenched, under standard conditions, by a jet of water impinging at one end. When the specimen is cool, determinations of hardness are made along it from the quenched end. The diagram relating hardness to distance from the quenched end of the specimen is known as a hardenability curve. Hammond Jones riffle An apparatus used for cutting the size of a sample. It consists of a hopper above a series of open-bottom pockets, usually 1/2 in or 3/4 in (1.27 cm or 1.91 cm) wide, which are so constructed as to discharge alternately, first into a pan to the right, and then into another pan to the left. Each time the sample is passed through the riffle, it is divided into two equal parts; the next pass of one of those parts will give a quarter of the original sample, and so on, until the sample is reduced to the desired weight. Pearl Jones splitter 1682

A device used to reduce the volume of a sample consisting of a belled, rectangular container, the bottom of which is fitted with a series of narrow slots or alternating chutes designed to cast material in equal quantities to opposite sides of the device. Also called sample splitter. CF: riffle Joosten process Method of soil consolidation used in tunneling through sands and gravels. Solutions of calcium chloride and sodium silicate are forced into the ground, where they mingle and produce a watertight gel. Pryor, 3 Joplin jig A device used for jigging the shaker products of the diamond washer. The products are fed to the jigs, one at a time, and jigged, with frequent stoppages for scraping off the top layer of tailings; more sand is added, and the process is repeated until a product is obtained that consists entirely of concentrates. Griffith jordanite A monoclinic mineral, Pb14 (As,Sb)6 S23 ; pseudohexagonal; forms a series with geochronite in which antimony increases relative to arsenic. joren A scoop-shaped bamboo basket used in Japan for carrying auriferous gravel. jose#1.ite A trigonal mineral, Bi4 TeS2 ; sp gr, 7.9; at San Jose, Minas Gerais, Brazil. A related mineral, jose#1.ite-B, contains more tellurium and less sulfur. josen See: hartite josephinite A gray, nickeliferous iron, Fe2 Ni5 or FeNi3 . Massive, granular, and forms the metallic portion of rolled pebbles. From Josephine County, OR. Syn: native nickel-iron joule

1683

a. The absolute meter-kilogram-second (mks) unit of work or energy that equals 107 erg or approx. 0.7377 ft.lb or 0.2390 g (caloric); the standard in the United States. Webster 3rd b. The gram-degree centigrade thermal unit; the small calorie. Standard, 2 Joule's law The rate at which heat is produced by a steady current in any part of an electric circuit is jointly proportional to the resistance and to the square of the current. Webster 3rd jouph holes Derb. Hollows in a vein. jourado diamond A colorless synthetic spinel used as a simulated diamond. journal That part of a rotating shaft resting in a bearing. Long journey a. Welsh term for train of mine cars moved mechanically. Also called gang; set; rake. Pryor, 3 b. A cycle of work done in glass manufacturing in converting a quantity of material into glass or glass products. Webster 3rd Joy double-ended shearer A cutter loader for continuous mining on a longwall face. It consists of two cutting heads fixed at each end of a continuous-track-mounted chassis. The heads are pivoted and controlled hydraulically for vertical movement. Each head comprises two bores and a frame or loop cutter that trims the bottom, face, and top. A cross conveyor delivers the coal to the adjacent face conveyor. The machine cuts a web of 5 ft (1.5 m) in seams from 37-1/2 in (95 cm) to 5 ft high. With an overall length of 18 ft (5.5 m), it weighs 15 st (13.6 t). Nelson Joy extensible conveyor A belt conveyor to serve between a loader or continuous miner and the main transport. It consists of two main units, a head and a tail section, each mounted on crawler tracks and independently driven. In operation, the tail unit (i.e., the receiving end) moves forward with the loading machine, and belting is automatically released from a loop takeup. Fifty feet (15 m) of advance is possible before additional belting has to be inserted into the conveyor run. Capacity equals 280 st/h (254 t/h) with a 30-in (76-cm) belt. Nelson 1684

Joy extensible steel band An arrangement to provide a link between a continuous miner and the main transport. The equipment is hydraulically driven, and the steel band is coiled on the drivehead. Nelson Joy loader Loading machine for coal or ore that uses mechanical arms to gather mineral onto an apron pressed into the severed material. A built-in conveyor then lifts it into tubs or onto a conveyor. Pryor, 3 Joy microdyne A wet-type dust collector for use at the return end of tunnels or hard headings. It may be either 6,000 ft3 /min or 12,000 ft3 /min (2.8 m3 /s or 5.7 m3 /s) in capacity. It wets and traps dust as it passes through the appliance, and releases it in the form of a slurry, which is removed by a pump. The microdyne is bolted to the outby end of the exhaust pipe, and the auxiliary fan is bolted to the outby end of the dust collector. Nelson Joy transloader A rubber-tired, self-propelled loading, transporting, and dumping machine. Joy walking miner A continuous miner with a walking mechanism instead of crawler tracks. The walking mechanism was adopted to make the machine suitable for thin seams. The lowest crawler-track-mounted machine can operate in a minimum seam height of 4 ft (1.2 m), whereas the walking type can work in a 2.5-ft (0.76-m) seam. Syn: walking miner jubilee wagon A small wagon, running on rails, which tips sideways. Hammond jubs Eng. Top jubs and bottom jubs, soft marly limestone, coarsely oolitic in places, in the Great Oolite at Kingsthorpe, Northamptonshire; also in the same formation at Bedford. Arkell jud a. N. of Eng. A block of coal about 4 yd (3.7 m) square, holed and cut ready for breaking down. Fay b. In whole working, a portion of the coal laid out and ready for extraction; 1685

in pillar working (i.e., the drawing or extraction of pillars), the yet unremoved portion of a pillar. Fay c. Applied to a working place, usually 6 to 8 yd (5.5 to 7.3 m) wide, driven in a pillar of coal. When a jud has been driven the distance required, the timber and rails are removed, and this is termed "drawing a jud." Zern d. Som. See: jad; lift. judge a. Derb.; Newc. A measuring stick to measure coal work underground. See also: judge rapper b. Eng. Formerly a youth who proved the holing. Fay judge rapper The upper end of the vertical arm of a judge. See also: judge Fay Judson powder A blasting explosive containing sodium nitrate, sulfur, coal, and a little nitroglycerin. Webster 2nd jug A colloquial equivalent of seismic detector, geophone, etc. See also: geophone jugglers Timbers set obliquely against pillars of coal to carry a plank partition, making a triangular air passage or manway. Fay julienite Possibly a tetragonal mineral, Na2 Co(SCN)4 .8H2 O ; a blue thiocyanate that may be an artifact. jumble Derb. The place where veins intersect. Fay jumbler Big Jumbler, a bed of limestone in the Lower Lias at Rugby, United Kingdom. jumbles The thickest oolitic bed in the Carboniferous limestone of the Clee Hills, Shropshire, United Kingdom. 1686

jumbo a. In mining, a drill carriage or mobile scaffold on which several drills of drifter type are mounted. It is used in tunnels and large headings. Pryor, 3 b. An asbestos-fiberizing machine that is effective for moderately soft ore where crushing or breaking is not required. Sinclair, 7 c. A mobile scaffold to assist drilling in large headings. BS, 12 d. A number of drills mounted on a mobile carriage and used in tunnels. Nichols, 1 e. Drilling platform used in tunneling. Sandstrom jump a. See: jumping a claim b. A sudden rise in the dip of a coal seam. Arkell jump correlation Identification of events on noncontiguous seismic records as involving the same interfaces in the Earth. AGI jumper a. The borer, steel, or bit for a compressed-air rock drill. CTD b. A long steel bar, or light aluminum tube with a steel end, used to dress rock faces, pry off loose rock, etc. Pryor, 3 c. Person who jumps a claim; i.e., takes possession of another's mining property. Pryor, 3 d. A steel bar used in manual drilling. Sandstrom jumper bar A weighted steel bar with a cutting edge; raised and dropped by hand. CTD jumping a claim a. Taking possession of a mining claim liable to forfeiture owing to the requirements of the law being unfulfilled. b. Taking possession of a mine or claim by stealth, fraud, or force. Syn: jump c. The act of locating a mining claim on supposed excess ground within staked boundaries of an existing claim on the theory that the law governing the manner of making the original location had not been complied with. Fay jump sheet A flat metal plate used as a turnsheet on which to turn the empty cars. Lewis junckerite See: siderite 1687

junction a. The point where two or more passageways intersect horizontally or vertically. AGI b. In ventilation surveys, where three or more airways meet. Roberts, 1 c. The union of two lodes. Gordon junction box In mining, a stationary piece of enclosed apparatus from which one or more electric circuits for supplying mining equipment are connected through overcurrent protective devices to an incoming feeder circuit. junk a. Any foreign metallic material accidentally introduced into a borehole. Long b. Very poor or low-grade drill diamond. Long junkerite See: siderite junket a. Eng. A bucket used for raising rock or ore in a shaft. Hess b. Eng. See: kibble junking a. The process of cutting a passage through a pillar of coal. CTD b. N. of Eng. An opening cut into, or a narrow slice taken off, a pillar in the room-and-pillar system of working coal. A fast junking is a narrow place driven lengthwise in a pillar of coal, but unholed into the room on either side of the pillar. A loose junking is a similar place driven along the side of the pillar and open to the room along that side. Fay junk mill A bit designed to grind or cut foreign metallic material or junk in a borehole into pieces small enough to be washed out of the hole or recovered by a basket. CF: milling bit; rose bit. Long junks a. Dev. Limestone concretions in slate. b. Corn. Joints in rocks. Jupiter process 1688

A patented process for making cast steel by melting wrought-steel scrap with about 2.0% ferrosilicon, up to about 0.5% ferromanganese, and about 3.0% aluminum, then casting in molds of a special composition. Jupiter steel A steel produced by the Jupiter process; it is about as strong and as ductile as forged steel. Jurassic The second period of the Mesozoic Era (after the Triassic and before the Cretaceous), thought to have covered the span of time between 190 million years and 135 million years ago; also, the corresponding system of rocks. It is named after the Jura Mountains between France and Switzerland, in which rocks of this age were first studied. AGI jury rig Any temporary or makeshift device, rig, or piece of equipment. Hunt jutty A small tub or truck used for gathering coal in thin seams. CTD juvenile a. Said of an ore-forming fluid or mineralizer that is derived from a magma, via fractional crystallization or other plutonic mechanism, as opposed to fluids of surface, connate, or meteoric origin. AGI b. A term applied to water and gases that are known to have been derived directly from magma and are thought to have come to the Earth's surface for the first time. AGI c. In the classification of pyroclastics, the equivalent of essential; derived directly from magma reaching the surface. AGI juvenile water Water from the interior of the Earth that is new or has never been a part of the general system of ground water circulation. CF: magmatic water juxtaposition twin See: contact twin

K 1689

kaemmererite Chromian clinochlore. Alternate spelling of kaemmererite. kaersutite A monoclinic mineral, NaCa2 (Mg,Fe)4 Ti(Si6 Al2 )O22 (OH)2 ; amphibole group with Mg/(Mg+Fe)= 0.5 to 1.0; forms a series with ferrokaersutite; a typical constituent of alkaline volcanic rocks. kahlerite A tetragonal mineral, Fe(UO2 )2 AsO4 )2 .10-12H2 O ; autunite group; forms lemonyellow plates; at Carinthia, Austria. kalamin See: calamine Kaldo steel process A steelmaking process in which oxygen is fed into a large inclined rotating vessel through water-cooled lances, but at velocities somewhat lower than in the L.D. steel process, so that the jet does not completely or continuously penetrate the slag layer. In some respects, it is like a continuously rotating open hearth. It gives better heat utilization than the L.D. steel process but is slower. Nelson kale Eng. Surface-weathered ironstone or oolite; rottenstone; in Northamptonshire, Rutland, and Lincolnshire. Also spelled keale. Arkell kaliborite A monoclinic mineral, KHMg2 B12 O16 (OH)10 .4H2 O ; formerly called heintzite, hintzeite, paternoite. See also: heintzite kalicine See: kalicinite kalicinite A monoclinic mineral, KHCO3 ; colorless, white, or yellow. Also spelled kalicine; kalicite. 1690

kalinite A possibly monoclinic mineral, KAl(SO4 )2 .11H2 O . Syn: potash alum kaliophilite A hexagonal mineral, KAlSiO4 ; polymorphous with kalsilite, panunzite, and trikalsilite. Syn: facellite; phacellite. kaliphite A mixture of limonite with oxides of manganese and silicates of zinc and lime. Osborne kalistrontite A trigonal mineral, K2 Sr(SO4 )2 ; occurs in prisms and plates with anhydrite and dolomite in a drill core from Alshtan, Bashkir, Russia. Kalling's solution An etching reagent for developing the microstructure of chromium steels with more than 5% of chromium. It contains 5 g copper chloride, 100 mL hydrochloric acid, 100 mL alcohol, and 100 mL water. Osborne kalsilite A hexagonal mineral, 2[KAlSiO4 ] ; polymorphous with kaliophilite, panunzite, and trikalsilite; forms a partial series toward nepheline; in groundmasses of potassium-rich, silica-poor lavas and as an alteration of blast furnace brick. kamacite A meteorite mineral consisting of the body-centered cubic alpha-phase of a nickel-iron alloy, with a fairly constant composition of 5% to 7% nickel. It occurs in iron meteorites as bars or girders flanked by lamellae of taenite. See also: nickel iron kamarezite A grass-green, hydrated, basic copper hydrate and sulfate, Cu3 (OH)4 SO2 .6H2 O . Syn: brochantite kaemmererite A chromian variety of clinochlore. 1691

kammerling furnace A modification of the Belgian zinc smelting furnace wherein there are two combustion chambers separated by a central longitudinal wall. In principle, the furnace is similar to the Hauzeur, a compound furnace. kanase Burma (Myanmar). A local custom in the gem mines at Mogok that permits women to work without licenses in streambeds, tailraces, and dumps from mines and washeries and to keep any gems they find. Hess Kanawhan Upper Lower Pennsylvanian. AGI Kanawha series A group of productive coal measures occurring in the Pennsylvanian of the Appalachian Region and completely developed in Virginia. Sometimes known as the Upper Pottsville series. CTD kandite See: kaolin kankar a. A term used in India for (1) masses or layers of calcium carbonate, usually occurring in nodules, found in the older alluvium or stiff clay of the Indo-Gangetic plain; or (2) precipitated calcium carbonate in the form of cement in porous sediments or as a coating on pebbles. AGI b. A limestone containing kankar and used for making lime and building roads. Etymol. Hindi. The term is occasionally applied in the United States to a residual calcareous deposit, such as caliche. Also spelled kunkur. AGI kaoleen A colloquial term used in south-central Missouri for a chalky, porous, weathered chert with a white to tan or buff color. Etymol. corruption of kaolin, to which the material bears a slight resemblance. AGI kaolin Former name for kaolinite. The aluminous minerals of the kaolinite-serpentine group. Syn: bolus alba; kaoline; kandite; kaolinite; white clay. 1692

kaoline See: kaolin kaolinic Of, relating to, or resembling kaolin. Webster 3rd kaolinite a. A monoclinic mineral, 2[Al2 Si2 O5 (OH)4 ]; kaolinite-serpentine group; kaolinite structure consists of a sheet of tetrahedrally bonded silica and a sheet of octahedrally bonded alumina with little tolerance for cation exchange or expansive hydration; polymorphous with dickite, halloysite, and nacrite; soft; white; formed by hydrothermal alteration or weathering of aluminosilicates, esp. feldspars and feldspathoids; formerly called kaolin. b. Kandites in general. c. Individual kandites not specif. designated. See also: alum salt; kaolin. kaolinite-serpentine The mineral group amesite, antigorite, berthierine, brindleyite, clinochrysotile, cronstedite, dickite, endellite, fraiponite, greenalite, halloysite, kaolinite, kellyite, lizardite, manandonite, nacrite, nepouite, orthochrysotile, parachrysotile, and pecoraite. CF: serpentine kaolinization Replacement or alteration of minerals, esp. feldspars and micas, to form kaolin as a result of weathering or hydrothermal alteration. CF: argillation; argillization. AGI kapel See: capel kappa carbide A carbide of iron, Fe23 C6 , in which all or part of the iron may be replaced by chromium, molybdenum, and/or tungsten, (Fe,Cr,Mo,W)23 C6 . Osborne karang Term used in the Malay States for the pay streaks of cassiterite. Lewis karat 1693

One-twenty-fourth part. It is used to designate the fineness of gold; thus, 18-karat gold is 18/24 (or 75%) pure gold and 6/24 (or 25%) other alloying metal or metals. Not to be confused with carat. karelianite A trigonal mineral, V2 O3 ; hematite group; black; in boulders from the Outokumpu orebody in the Karelian schist belt, Finland. Karlsbad twin See: Carlsbad twin karnasurtite A possibly hexagonal mineral, (Ce,La,Th)(Ti,Nb)(Al,Fe)(Si,P)2 O7 (OH)4 .3H2 O(?) ; metamict; at Mt. Karnasurt, Kola Peninsula, Russia. karpatite A monoclinic mineral (coronene), C24 H12 . Also spelled carpathite. Syn: pendletonite karpinskite A possibly monoclinic mineral, (Mg,Ni)2 Si2 O5 (OH)2 (?) ; greenish blue; with talc in serpentinite from the Ural Mountains, Russia. (Not karpinskyite.) karpinskyite A mixture of leifite and a zinc-bearing smectite. (Not karpinskite.) karst A type of topography that is formed on limestone, gypsum, and other rocks by dissolution, and that is characterized by sinkholes, caves, and underground drainage. Etymol. German, from the Yugoslavian territory Krs; type locality, a limestone plateau in the Dinaric Alps of northwestern Yugoslavia and northeastern Italy. First published on a topographic map, Ducatus Carnioliae, in 1774. Adj. karstic. Syn: karst topography AGI karst topography See: karst kasoite 1694

A potassian variety of celsian. kasolite A monoclinic mineral, Pb(UO2 )SiO4 .H2 O ; radioactive; an oxidation product of uraninite; at Kasolo, Katanga, Zaire. Formerly called droogmansite. Kast furnace A small, circular shaft furnace with three or four tuyeres, for lead smelting. Fay kataSee: catakataclastic See: cataclastic kata cooling power A measure of the cooling effect of the ambient air as determined by the kata thermometer. This instrument may be used wet or dry. BS, 8 katamorphism Destructive metamorphism in the katamorphic zone, at or near the Earth's surface, in which complex minerals are broken down and altered through oxidation, hydration, solution, and allied processes to produce simpler and less dense minerals. The term was introduced by Van Hise in 1904. Also spelled catamorphism. CF: anamorphism kata thermometer A type of alcohol thermometer used to determine the cooling power of the ambient air and sometimes to measure low air velocities. BS, 8 katazone According to Grubenmann's classification of metamorphic rocks (1904), the lowermost depth zone of metamorphism, which is characterized by high temperatures (500 to 700 degrees C), mostly strong hydrostatic pressure, and low or no shearing stress. It produces rocks such as high-grade schists and gneisses, granulites, eclogites, and amphibolites. The concept includes effects of high-temperature contact metamorphism and metasomatism. Modern usage stresses temperature-pressure conditions (highest 1695

metamorphic grade) rather than the likely depth of zone. Also spelled catazone. CF: mesozone; epizone. See also: katamorphism AGI katoptrite A monoclinic mineral, (Mn, Mg)13 (Al, Fe)4 Sb2 Si2 O28 ; in jet-black crystals in limestone at Nordmark and Laangban, Sweden. katungite A volcanic rock composed chiefly of melilite, with subordinate olivine and magnetite and minor leucite and perovskite; a pyroxene-free melilitite. AGI kauk A very heavy substance, common in the mines, Derbyshire, U.K. Also spelled cauk. kayserite See: diaspore K-bentonite See: potassium bentonite kearsutite Misspelling of kaersutite. keatite Synthetic tetragonal silica, SiO2 ; crystallized hydrothermally at high pressure. keeleyite See: zinkenite keel wedge A long iron wedge for driving over the top of a pick hilt. Fay keen sand Forest of Dean. Sand forming poor rye soil. 1696

keeper Person in charge of opening and closing the taphole of a blast furnace and who runs iron at cast. Fay Keewatin A division of the Archeozoic rocks of the Canadian Shield. It is older than the Timiskamian. Also spelled Keewatinian. AGI keg A cylindrical container made of steel or some other substance, which contains 25 lb (11.4 kg) of blasting powder or gunpowder. Any small cask or barrel having a capacity of 5 to 10 gal (18.9 to 37.9 L). Fay kehoite Amorphous (Zn,Ca)Al2 (PO4 )2 .5H2 O ; a doubtful mineral species. keldyshite A triclinic mineral, Na2-2Dx Hx ZrSi2 O7 .nH2 O ; forms irregular grains in the Lovozero massif, Kola Peninsula, Russia. kell A variation of kiln. Fay Keller automatic roaster A six-deck horizontal furnace for calcining sulfide ores. Fay Keller furnace A multiple-deck roasting furnace for sulfide ore. It is a modification of the Spence furnace. Fay kellerite A cuprian variety of pentahydrite. kellow Black lead or wad, Cumberland, U.K. 1697

kelly The rod attached to the top of the drill column in rotary drilling. It passes through the rotary table and is turned by it, but is free to slide down through it as the borehole deepens. Also called grief stem. BS, 9 kelly bar A hollow bar attached to the top of the drill column in rotary drilling; also called grief joint; kelly joint; kelly stem. Meyer Kelly filter An intermittent, movable pressure filter. The leaves are vertical and are set parallel with the axis of the tank. Pulp is introduced into the tank (a boilerlike affair) under pressure, and the cake is formed. The head is then unlocked, the leaves are run out of the tank chamber by means of a small track, and the cake is dropped. The carriage and leaves are then run back into the tank, and the cycle begins again. Liddell kelp The ashes of seaweeds, formerly the source of soda as used in glassmaking and soapmaking; now a source of potash, iodine, and char. Standard, 2 kelvin a. Board of Trade unit of energy (1 kW/h). Pryor, 3 b. See: Kelvin temperature scale Kelvin temperature scale The absolute temperature scale in which the temperature measure is based on the average kinetic energy per molecule of a perfect gas. The zero of the Kelvin scale is -273.16 degrees C. The temperature scale adopted by the International Bureau of Weights and Measures is that of the constant volume hydrogen gas thermometer. The magnitude of the degree in both these scales is defined as one one-hundredths the difference between the temperature of melting ice and that of boiling water at 760 mm pressure. See also: temperature Handbook of Chemistry and Physics, 2 kelyphite See: corona kelyphitic rim See: corona 1698

kelyphytic A term applied to the rims or borders consisting of microcrystalline aggregates of pyroxene or amphibole occurring around olivine, where it would otherwise be in contact with plagioclase, or around garnet, where it would otherwise be in contact with olivine or other magnesium-rich minerals. kelyphytic rim See: corona Kema plow A scraper-box type of plow for use on longwall faces. See also: scraper box plow kempite An orthorhombic mineral, Mn2 Cl(OH)3 ; forms minute emerald-green prismatic crystals; at Alum Rock Park, CA. kennel coal A coal that can be ignited with a match to burn with a bright flame. Syn: candle coal kentrolite An orthorhombic mineral, Pb2 Mn2 Si2 O9 ; forms a series with melanotekite; massive or in sheaflike prismatic crystals; at Laangban and Nordmark, Sweden, and Sassari, Sardinia, Italy. Kent roller mill A revolving steel ring with three rolls pressing against its inner face. The rolls are supported on springs, and the rings support the roll, so that there is some freedom of motion. The material to be crushed is held against the ring by centrifugal force. Liddell kentsmithite A local name used in the Paradox Valley, Colorado, for a black, vanadium-bearing sandstone. Syn: vanoxite kep a. One of the steel supports on which a cage rests at the pithead during unloading or loading so that the rail track is always at the proper level. During this period, the rope is 1699

released from the weight of the cage. The ordinary type of kep gear consists of four steel arms, two for each end of the cage, carried on shafts that are connected to and operated by levers. Normally, the cage must be raised from the kep arms before the latter can be withdrawn to allow the cage to descend the shaft. See also: Beien kep gear; cage stop. Nelson b. One of the retractable rests on which the mine cage is supported during its stop at a shaft landing. Also called catch; chair; keep; landing chair; stop. Pryor, 3 c. One of the bearing-up stops for supporting a cage or load at the beginning or end of hoisting in a shaft. CTD kepel Corn. Spar or hard stone on each side of the lode. kerargyrite See: cerargyrite keratophyre A name generally applied to all salic extrusive and hypabyssal rocks characterized by the presence of albite or albite-oligoclase and chlorite, epidote, and calcite, generally of secondary origin. Some varieties of keratophyre contain sodic orthoclase, sodic amphiboles, and pyroxenes. Keratophyres commonly are associated with spilitic rocks and interbedded with marine sediments. AGI kerf a. The undercut usually made in the coal to facilitate its fall. BCI b. A horizontal cut in a block of coal, as opposed to a shearing, which is a vertical cut. BCI c. Undercut in a coal seam from 3 to 7 in (7.6 to 18 cm) thick and entering the face to a depth of up to 4 ft (1.2 m), made by a mechanical cutter. Also called kirve. Pryor, 3 d. The undercut made in a coalbed to assist the action of explosives in blasting. Hudson e. The annular groove cut into a rock formation by a core bit. See also: kerve f. The space that was occupied by the material removed during cutting. ASM, 1 g. The thickness of the wall of the diamondinsert part of the crown of a core bit. Long h. Sometimes incorrectly used as a syn. for nose, as applied to a diamond core bit. Long kerf stone One of the diamonds inset in the kerf of the crown of a diamond bit. Also called face stone. Long kermesite

1700

A triclinic mineral, Sb2 S2 O ; pseudomonoclinic; occurs as soft tufts of cherry-red capillary crystals with one perfect cleavage; an alteration product of stibnite. Syn: antimony blende; pyrostibite; pyrostibnite; red antimony; pyroantimonite. kerned stone Corn. Sand blown off the seashore into the country and concreted there. kernel Atom that has lost the valence electrons of its outermost shell. Pryor, 3 kernel roasting See: roasting kernite A monoclinic mineral, 4[Na2 (H2 O)3 B4 O6 (OH)2 ] ; soft, colorless to white; in the Mojave Desert and Kern County, CA; a major source of borax and boron compounds in the United States. See also: Rasorite kerogen a. A term generally used for organic matter in sedimentary rocks that is insoluble in common organic and inorganic solvents. b. The solid, organic substance in shales that yields oil when the shales undergo destructive distillation. kerogen shale See: oil shale kerolite A variety of talc with randomly stacked structure; forms a series with nickel-kerolite. Also spelled cerolite. keronigritite A type of nigritite that is derived from kerogen. CF: polynigritite; humonigritite. AGI kerosine flotation As sometimes practiced, this method is a combination of bulk oil flotation and froth flotation. By adding large quantities of kerosine to a pulp plus a small amount of frother 1701

and agitating vigorously, surfaces of the amenable mineral (coal) are attracted to both the oil and air bubbles, forming heavy flocs. This type of concentrate is more readily dewatered than ordinary froth and therein lies its advantage, plus the fact that coarser particles (6 to 10 mesh) can be handled than in ordinary froth flotation. Also called granulation. Syn: agglomeration kerosine shale Substance originally described as a variety of oil shale but later proved to be similar to torbanite. See also: boghead coal; torbanite. Tomkeieff kerrite A variety of vermiculite. kersantite A lamprophyre containing biotite and plagioclase (usually oligoclase or andesine), with or without clinopyroxene and olivine. Defined by Delesse in 1851; named for the village of Kersanton, France. AGI kerve N. of Eng. In coal mining, to cut under. See also: kerf kirve. Zern kesterite A mineral, (Cu,Sn,Zn)S, containing 30.36% copper, 25.25% tin, 11.16% zinc, and 23.40% sulfur. In quartz sulfide ore from Kester, Magadan, Yakutia, northeast Siberia, Russia. Named from locality. Syn: isostannite; khinganite. Spencer, 6 kettle A depression in the ground surface formed by the melting of a large, detached block of stagnant ice wholly or partly buried by glacial drift. AGI kettleback See: horseback; slip. kettle bottom a. A smooth, rounded piece of rock, cylindrical in shape, which may drop out of the roof of a mine without warning, sometimes causing serious injuries to miners. The surface usually has a scratched, striated, or slickensided appearance and frequently has a slick, 1702

soapy, unctuous feel. The origin of this feature is thought to be the remains of the stump of a tree that has been replaced by sediments so that the original form has been rather well preserved. Sometimes spelled kettlebottom. Also called bell; pot; camelback; tortoise. Syn: caldron pot bottom. CF: black bat b. See: horseback; caldron bottom. kettle dross Skimmings resulting from the desilverization of lead bullion. It consists principally of lead oxides mixed with metallic lead. Fay kettleman In ore dressing, smelting, and refining, a person who (1) refines lead in a series of oilfired kettles, and (2) removes silver and copper from black mud in a gas-fired kettle, preparatory to the separation of gold. DOT kettle operator In ore dressing, smelting, and refining, a person who melts and fumes antimony in oilfired kettles to make antimony oxide. DOT kettnerite A tetragonal mineral, CaBi(CO3 )OF ; in pegmatite from Krupka, Czech Republic. kevell Calcspar from Derbyshire lead mines, United Kingdom. Also spelled kebble. kevil a. Derb. A veinstone, consisting of a mixture of calcium carbonate and other minerals. Fay b. N. of Eng. The amount of coal sent out by the various miners during a certain period. Fay Keweenawan A provincial series of the early Proterozoic in Michigan and Wisconsin. AGI key The pieces of core causing a block in a core barrel, the removal of which allows the rest of the core in the core barrel to slide out. See: legend key bed 1703

a. A well-defined, easily identifiable stratum or body of strata that has sufficiently distinctive characteristics (such as lithology or fossil content) to facilitate correlation in field mapping or subsurface work. AGI b. A bed, the top or bottom of which is used as a datum in making structure-contour maps. Syn: key horizon; index bed; marker bed. AGI key blocks The first blocks that are removed in opening up a new quarry floor. keyhole slot A slot enlarged at one end to allow entrance of a chain or bolt that can then be held by the narrow end. Nichols, 1 key horizon See: key bed keystone a. A symmetrically tapered piece at the center or crown of an arch. b. A filling-in block of cast iron used in some lead smelting furnaces. Webster 2nd keystoneite Blue chalcedony colored by chrysocolla. K-feldspar The mineral microcline, orthoclase, or sanidine. Syn: potassium feldspar K-Fuel process In this process, the feed coal is heated sufficiently to remove all the moisture from the coal and to mildly carbonize it. The carbonized hot coal, in a plastic state, flows to an extruder which agglomerates the product into pellets. Khari salt A native mineral salt of India, predominantly sodium chloride with large amounts of sodium sulfate, the composition varying greatly with locality where obtained. Synthetic Khari salt has 40% anhydrous sodium sulfate. Kaufmann khinganite 1704

See: kesterite khlopinite A titanian variety of samarskite. kibbal See: kibble kibble a. Steel bucket used during shaft sinking. Pryor, 3 b. To carry in a hoisting bucket, such as ore. Syn: junket; kibbal. Standard, 2 kibble rope Eng. A rope or chain for hoisting a kibble or bucket. Standard, 2 kick a. Assay with metal values. Also, a geophysical indication of ore. As opposed to background values. (Slang only.) Hoffman b. A small sidewise displacement or offset in a borehole caused by the sidewise deviation of a bit when entering a hard, tilted rock stratum underlying a softer stratum. Long c. A quick snap of the drill stem caused by the core breaking in a blocked core barrel or sudden release of a momentary bind. CF: step Long kick back a. Arkansas. To break the coal on both sides of the auger hole that contains the powder, usually along a joint in the coal. Fay b. A track arrangement for reversing the direction of travel of cars moving by gravity. Fay kicker a. Ground left, in first cutting a vein, for support of its sides. b. Also, a gage stone handset in the outside surface or wall of the metal shank of a diamond bit. Syn: gage stone kicker stone See: gage stone kicking pieces 1705

Short struts to prevent a sill or other member from being pushed out of place. Stauffer kickoff point The place in a borehole where the first intentional deviation starts. Sometimes abbreviated KOP. Long Kick's law The amount of energy required to crush a given quantity of material to a specified fraction of its original size is the same no matter what the original size. CF: Rittinger's law kidney iron ore A reuniform variety of hematite with concentric or radiating structure. Syn: kidney stone; kidney ore. See also: iron ore kidney ore See: kidney iron ore kidneys A mineral zone that contracts, expands, and again contracts downwards. AGI kidney stone a. See: nephrite; kidney iron ore; urolith. b. Any reniform nodule. kidney sulfur See: lense kies A general term for the sulfide ores, adopted into English from the original German. kieselguhr See: diatomite kieserite

1706

a. A monoclinic mineral 4[MgSO4 .H2 O] ; in evaporite salt deposits from dehydration of epsomite or decomposition of kainite. Syn: martinsite b. The mineral group dwornikite, gunningite, kieserite, poitevinite, szmikite, and szomolnokite. kilbrickenite See: geochronite kilchoanite A orthorhombic mineral, Ca3 Si2 O7 ; dimorphous with rankinite, which it replaces at Kilchoan, Ardnamurchan, Scotland. kilkenny coal See: anthracite kill To mix atmospheric air with combustible gases or other gases so as to make them harmless. Fay killas a. Corn. The slates or schists that form the country rock of the Cornish tin veins. b. Corn. Term used in the china-clay mines for the altered schistose or hornfelsic rocks in contact with the granite and often considerably modified by emanations from the latter. Dodd killed steel Steel treated with a strong deoxidizing agent, such as silicon or aluminum, to reduce the oxygen content to such a level that no reaction occurs between carbon and oxygen during solidification. ASM, 1 killing a. Allowing the molten steel to remain in the crucible for about 45 min for the escape of the gases. Mersereau, 2 b. In metallurgy, esp. in foundry terminology, a term for deoxidation. Gaynor kiln

1707

a. A large furnace used for baking, drying, or burning firebrick or refractories, or for calcining ores or other substances. ASM, 1 b. A furnace or oven, which is usually made from refractory brick, used to dry and fire various types of ceramic ware. kiln burner A worker who is responsible for firing kilns to produce ceramic products. Type of product produced is often attached to the term as, brick kiln burner, tile burner, pipe burner, etc. Also called kiln fireman; kiln operator; baker; kiln tender; kiln firer, etc. kiln-burner helper Person who assists kiln burner in firing kiln, supplying coal and wood to fireboxes, and cleaning ashes from ashpits. DOT kiln-car unloader A worker who removes fired ceramic ware from kiln cars. kiln cleaner Person who prepares kilns for burning. DOT kiln-dry To dry in a kiln. Webster 3rd kilneye An opening for removal of lime from a vertical lime kiln. kilnman A worker who tends a kiln. Standard, 2 kiln placer A worker who places clayware in kiln for drying or firing. Also called kiln setter; sagger filler; kiln loader; kiln stacker. kiloOne thousand units. The kilodyne is 1,000 dyn; kilogram is 2.2046 lb avoirdupois; kilometer is 1,093.6 yd; kilowatt is 1.341 hp. Pryor, 3 1708

kilocusec A unit of volumetric rate of air flow, expressed in thousands of cubic feet per second. BS, 8 kilocycle One thousand cycles. Abbrev. kc. Crispin kilometer A length of 1,000 m; equals 3,280.8 ft or 0.621 mile. The chief unit for long distances in the metric system. Abbrev. km. Standard, 2 kiloton A unit for measuring the energy of a nuclear explosion. A 1-kiloton explosion releases energy equal to that in the explosion of 1,000 st (907 t) of TNT. Abbrev. kton. Lyman kilowatt-hour A unit of work or energy equal to that expended in 1 h at a steady rate of 1 kW or 3.6 x 106 J. Webster 3rd Kimberley method See: combined top slicing and shrinkage stoping kimberlite A highly serpentinized porphyritic peridotite, commonly brecciated, which occurs in vertical pipes, dikes, and sills. It is the principal original environment of diamond, but only a small percentage of the known kimberlite occurrences are diamondiferous. See also: blue ground; yellow ground. The name is derived from Kimberley, South Africa. kimzeyite An isometric mineral, Ca3 (Zr,Ti)2 (Si,Al,Fe)3 O12 ; garnet group. kind Eng. Generally signifies tender, soft, or easy to work; said of certain ores. Kind-Chaudron process 1709

A method of sinking a deep shaft of large diameter in which a pilot bore of smaller diameter is first cut, after which the cut is enlarged to the final diameter, the debris falling into the pilot bore. When water is encountered, a lining with a moss box at the bottom is forced into place. CF: Triger process kindly See: likely kindly ground Eng. Those rocks in which lodes become productive of mineral of value. kindred See: rock association kinematic viscosity Ratio of absolute viscosity to mass density. Measured in square meters per second. Hartman, 2 kinetic energy The form of mechanical energy a body possesses by virtue of its velocity. The kinetic energy of a body, or the energy of motion, is the work done by it, or against it, in coming to rest. Water flowing through pipes or air flowing through a mine roadway possesses kinetic energy. See also: velocity head kinetic head The energy of flowing water that is a function of its velocity. kinetic metamorphism A type of metamorphism that produces deformation of rocks without chemical reconstitution or recrystallization to form new minerals. AGI kingbolt a. The bolt with which a cage is attached to the hoisting cable. It supports the suspended cage. b. A large bolt that holds the upper end of the tripod legs together and from which the sheave-wheel clevis is suspended. Long king brick 1710

Special, hollow, cylindrical fireclay brick, between the bottom fountain brick and the first lateral brick in a bottom-pour ingot assembly. See also: bottom-pour ingot assembly king pile In a wide excavation where strutting is required, this is a long pile driven at the strut spacing in the center of the trench before excavation is started. Hammond king post A vertical member of a stamp battery frame that carries the camshaft. CTD king screen A drum-type screen in which the pulp to be screened is delivered on the outside, the undersize passing through the screen and discharging through the open end. Liddell kink a. A sharp angular deflection in a borehole. Long b. A deflection in a vein or lode that does not interrupt its continuity. c. Scot. A twist in a rope; a doubling and interlocking of several links in a chain. Fay kink bands Microscopic to macroscopic deformation lamellae in mineral grains; e.g., quartz, pyroxene, mica, kyanite, resulting from plastic flow under tectonic strain. Also called translation gliding. kinradite Orbicular jasper containing spherical inclusions of colorless or nearly colorless quartz. kinzigite A coarse-grained metamorphic rock of pelitic composition occurring in the granulite facies. Essential minerals are garnet and biotite, with which occur varying amounts of quartz, K-feldspar, oligoclase, muscovite, cordierite, and sillimanite. The name is from Kinzig, Schwarzwald, Germany. AGI kip a. N. of Eng. A level or gently sloping roadway, at the extremity of an engine plane, upon which the full cars stand ready to be sent up the shaft. The tubs, or cars, usually go to the shaft by gravity. Fay b. A load of 1,000 lb (454 kg). ASM, 1 1711

kir Natural asphalt at the surface, Russia. Kirkup table A machine for dry cleaning coal. Raw coal is fed onto a perforated plate inclined at 12.5 degrees to 15 degrees to the horizontal. A pulsating air current is applied to the underside of the inclined plate, which stratifies the material, the coal forming the upper layer with the dirt below, which then passes into separate compartments. The Kirkup table gives a three-product separation; i.e., coal, middling, and reject. See also: pneumatic jig; pneumatic table; S.J. table. Nelson kirovite A magnesian variety of melanterite. CF: jarosite Kiruna method A borehole-inclination survey method whereby the electrolytic deposition of copper from a solution is used to make a mark on the inside of a metal container. CF: acid-dip survey kirve N. of Eng. To undercut. See also: kerve; kerf. Fay kirving a. Newc. The cutting made at the bottom of the coal by the miner. See also: holing b. Eng. Undercutting the coal horizontally, usually by hand. Also called laying-in; liggingin; holing. SMRB kirvings N. of Eng. Small coal, fragments, or cuttings lying in the undercut made by a cutting machine jib. Trist kish Free graphite that forms and floats out of molten hypereutectic cast iron as it cools. ASM, 1 kishly 1712

York. Hard, dry vein matter, poor in ore; in lead mines. Arkell kist a. Eng. The wooden box or chest in which the deputy keeps tools at the flat or inspection station; the station is said to be at the kist. SMRB b. N. of Eng. The meeting place in a district where workers assemble. (Strictly, the box in which the deputy keeps papers, etc.) Trist kit A wooden vessel. Fay kladnoite A monoclinic mineral (phthalimide), C6 H4 (CO)2 NH ; results from burning waste at the Kladno coal basin, Czech Republic. klaprothine See: lazulite klaprothite A discredited mineral since it is a mixture of wittichenite and emplectite. Am. Mineral., 1 klebelsbergite An orthorhombic mineral, Sb4 O4 (OH)2 (SO4 ) ; forms pale-yellow to orange-yellow platy or acicular crystals on stibnite; at Baia Sprie, Romania. kleinite A hexagonal mineral, Hg2 N(Cl,SO4 ).nH2 O ; yellow to orange; occurs as short prisms darkening on exposure; sp gr, 8.0; in Brewster County, TX. Klein solution A solution of cadmium borotungstate; sp gr, 3.6; used as a "heavy liquid" for mineral separation. CF: Clerici solution; methylene iodide; Sonstadt solution. kliachite See: cliachite 1713

klinkstone See: phonolite klintite A reef limestone, particularly the massive core. klippe An isolated rock unit that is an erosional remnant or outlier of a nappe. The original sense of the term was merely descriptive; i.e., included any isolated rock mass, such as an erosional remnant. Plural, klippen. See also: nappe floor. AGI klockmannite A hexagonal mineral, CuSe ; slate gray to reddish violet, tarnishing to blue-black; basal cleavage. Occurs at Sierra de Umango, Argentina; Harz Mountains, Germany; and Skrikerum, Sweden. kloof S. Afr. A mountain pass or cleft; a gorge or narrow valley. kmaite A former name for celadonite. See: celadonite Knapp bottom pressure gage An instrument designed for studying harbor surging. A strain gage unit, used in connection with pressure sensitive bellows, comprises the transducer of the pressure head. The four strain gages in the unit are connected to form a bridge circuit that is linked to the recorder by an electrical cable. A direct current voltage is applied to the bridge, and the record is obtained by recording the unbalanced current from a magnetic oscillograph. Any standard strain gage recorder can be used for the recording system. Hunt knapping machine An instantaneous stonecrushing machine; a stonebreaker. Standard, 2 kneading

1714

A filling material composed of clayey rock from which balls are made by a special machine. These balls are driven by an air current through a tube resembling a gun barrel into the excavated area to be filled. By impact and weight, the soft balls are squashed and perfectly fill the excavation. Stoces knebelite A manganoan variety of fayalite. knee brace A stiffener between a stanchion or column and a roof truss, to ensure greater rigidity in a building frame under wind load. Hammond kneeler a. The triangular connection by which a horizontal motion is changed to a vertical one, as in certain mine pumps. Standard, 2 b. A stone cut to provide a change of direction. Crispin c. The return of the dripstone at the spring of an arch. CTD knee pad A protective cushion, usually made of sponge rubber, that can be strapped to the miner's knee. knee piece a. A bent piece of piping. Fay b. An angular piece of timber used in a roof (mine) to strengthen a joint where two timbers meet. Fay knee timber a. Timber with natural knees or angles in it. Webster 3rd b. A piece of timber with an angle or knee in it. Webster 3rd knell stone N. of Eng. Freestone (sandstone). knife dog A tool that fits around and grips drill rods or any tubular drilling equipment so they can be pulled or lifted from a borehole where workspace in narrow underground openings is too confined to allow the use of a hoisting plug. Long 1715

knife edge a. The girdle of a brilliant, cut to a sharp edge and polished. Hess b. A narrow ridge of rock or sand. Syn: feather edge knife switch A switch that opens or closes a circuit by the contact of one or more blades between two or more flat surfaces or contact blades. Crispin knipovichite A chromian variety of alumohydrocalcite. knistersalze Crystals of salt mined at Wieliczka, Poland, that decrepitate violently upon heating, due to excessive enclosed water or gases. Kaufmann knitted texture A texture typical of the mineral serpentine in rocks where it replaces a clinopyroxene. CF: lattice texture knobbing The act of roughdressing stone in the quarry by knocking off the projections and points. Fay knobbing fire A bloomery for refining cast iron. Fay knobellite An intergrowth of galena with bismuthinite or stibnite. Hess knock To sound the mine roof for competence by rapping. knockbark Crushed lead ore. Arkell 1716

knocking a. S. Wales. Signals made underground by knocking on the coal. Fay b. Eng. Ore broken with a hammer, esp. the large lumps. Webster 2nd knockoff bit See: detachable bit knockout man A laborer who frees solidified metal castings from inverted molds of a casting wheel by prying the castings from the molds with a long steel bar to drop them into a water pit (bosh) for cooling. DOT knockstone Eng. Stone bench on which lead ore is buckered or broken small for the hotching tubs; Yorkshire lead mines. Also called binkstone. Arkell knogging Eng. Small refuse stones used for the inside of walls; Northamptonshire and Worcestershire. Arkell Knoop hardness Microhardness determined from the resistance of metal to indentation by a pyramidal diamond indenter, having edge angles of 172 degrees 30' and 130 degrees , and making a rhombohedral impression with one long and one short diagonal. CF: Mohs scale knot A small concretion; e.g., of galena in sandstone, or a segregation of darker minerals in granite and gneiss. AGI knots a. Nodules or concretions of pyrite. b. Any hard inclusions in a rock. c. Quarrymen's term for dark gray to black masses, more or less oval or circular in cross section, which are segregations of biotite or hornblende in granite. English quarrymen call them heathen. d. Diamonds with included small diamond crystals that cause trouble in cutting. knotted schist 1717

See: spotted slate knotted slate See: spotted slate known mine Land cannot be held to be a "known mine" unless at the time the rights of the purchaser accrued, there was upon the ground an actual and open mine that either had been worked or was capable of being worked. known to exist A vein or lode is known to exist when it could be discovered by anyone making a reasonable and fair inspection of the premises for the purpose of a location. known vein A vein or lode is known to exist within the meaning of the mining act when it could be discovered by or is obvious to anyone making a reasonable and fair inspection of the premises for the purpose of making a location of a placer mining claim. This term is not to be taken as synonymous with located vein and refers to a vein or lode whose existence is known as distinguished from one that has been appropriated by location. Hence, a regular location is not necessary before a vein or lode can be a known vein or lode. The time at which a vein or lode must be known to exist to except it from a placer patent is the time at which the application for a patent is made and to contain minerals in such quantity and quality as to justify expenditure for the purpose of extracting them. Ricketts knox hole A circular drill hole with two opposite vertical grooves that direct the explosive power of the blast. Fay knox system A system of separating masses of rock by blasting with black blasting powder in reamed drill holes, a considerable air space being left between the charge and the stemming. Fay knoxvillite See: copiapite knuckle 1718

The place on an incline where there is a sudden change in grade. The top of a grade or hill on a track over which mine cars are hauled. Fay knuckle joint A mechanism consisting of some form of two forks coupled together by means of a cube or sphere provided with projecting pins extending through holes provided in the outer end of each branch of the fork. When inserted between the bit and the drill rods, the mechanism can be used to deflect a borehole. A similar mechanism often is used as a connection between two shafts on a machine when the ends of the shafts are placed at an angle to each other. Long knuckle man In bituminous coal mining, a person who works at the knuckle (top) of a haulage slope, coupling trains of cars and attaching and detaching cars to and from a haulage cable by which they are raised or lowered. Also called knuckle boy. DOT knurs and fundlers Eng. Two words always used together and applied to lumps of gypsum in marl, Nottinghamshire. Arkell knurs and knots The stony nodules found lodged in the strata; commonly harder than the rest of the mass of the strata. Arkell kobeite An amorphous mineral, (Y,U)(Ti,Nb)2 (O,OH)6 (?) ; forms black metamict crystals at Kobe, Japan. kobellite An orthorhombic mineral, Pb22 Cu4 (Bi,Sb)30 S69 ; forms a series with tintinaite. kochenite A fossil resin, like amber. From Kochenthal, Tirol, Austria. English Koch freezing process A freezing method of shaft sinking, in which a solution of magnesium chloride, MgCl2 , is circulated through the freezing tubes instead of brine. The magnesium chloride is 1719

cooled to about -30 degrees C at the refrigerating plant, and this temperature is capable of freezing the ground without the solution itself freezing and choking the tubes. Anhydrous ammonia, carbon dioxide, or sulphur dioxide is used as the refrigerating agent. Nelson koechlinite An orthorhombic mineral, Bi2 MoO6 ; forms minute tabular crystals; at Schneeberg, Saxony, Germany. koehler lamp A naphtha-burning flame safety lamp for use in gaseous mines. Fay Koepe hoist Winding system in which both cages in a mine shaft are connected to the same rope, via the drum. Pryor, 3 Koepe sheave The wheel that is used in the Koepe winder instead of a winding drum. It usually consists of a cast-steel hub with steel arms and rim of welded construction. The diameter of the sheave varies from about 16 to 26 ft (4.9 to 7.9 m), depending on the size and type of winding rope and the total load. It is recommended that the ratio of the diameter of the sheave to the diameter of the rope should be 100:1 and that of the sheave to the largest wire in the rope, 2,000:1. A Koepe sheave is fitted with renewable friction linings. See also: sheave; winding sheave. Nelson Koepe system a. A system of hoisting without using drums, the rope being endless and passing over pulleys instead of around a drum. Zern b. In this system, the hoisting drum is replaced by a large driving sheave 15 to 20 ft (4.6 to 6.1 m) in diameter. The angle of contact of the rope with the sheave is from 190 degrees to 200 degrees or a little over a half circle. Driving is done through the friction grip of the sheave on the rope; therefore, a tail rope is used around a sheave at the bottom of the shaft to give the necessary pull on the slack side. Lewis Koepe winder A system where the winding drum is replaced by a large wheel or sheave. Both cages are connected to the same rope, which passes around some 200 degrees of the sheave in a groove of friction material. The Koepe sheave may be mounted on the ground adjacent to the headgear or in a tower over the shaft. The drive to the rope is the frictional 1720

resistance between the rope and the sheave. It requires the use of a balance rope. It is often used for hoisting heavy loads from deep shafts and has the advantage that the large inertia of the ordinary winding drum is avoided. The system has been widely used in Europe for many years, and some large projects in Great Britain are being equipped with winders of this type. See also: multirope friction winder Koepe winder brake A brake which acts directly on the Koepe sheave and can be applied by the winding engine operator's brake lever and the other safety devices. Nelson koettigite See: koettigite kohlenhobel See: coal plow kolbeckite A monoclinic mineral, ScPO4 .2H2 O ; blue to gray. Syn: sterrettite Kollen garnet Almandine from Kollen, Bohemia, Czech Republic. See also: Bohemian garnet kolm a. A variety of cannel coal occurring locally as lenticles in Swedish alum shales and containing 30% of ash rich in rare metals, including uranium and radium. Tomkeieff b. See: culm c. A variety of anthraxolite; a hydrocarbon that resembles oil shale. Crosby d. A shale impregnated with asphaltite. Hess kolovraite The mineral hydrous vanadate of Ni and Zn; in yellow botryoidal crusts; at Ferghana, Uzbekistan. komatiite Magnesium-rich ultramafic volcanic rock of high temperature origin. The term was originally applied by Viljoen and Viljoen (1969) to basaltic and ultramafic lavas near the Komati river, Barberton Mountain Land, Transvaal, South Africa. Nickel-copper sulfide mineral deposits may be associated with komatiites. 1721

kong Barren bedrock underlying tin-bearing gravel. Pryor, 3 konimeter Apparatus used to measure dust in mine atmosphere. A measured volume of air is drawn through a jet so as to impinge on a glass surface coated with glycerin jelly. The adherent dust is then examined and the particles are counted under the microscope. Also called Zeiss konimeter. See also: dust sampling koninckite A tetragonal mineral, FePO4 .3H2 O(?) ; occurs in yellow spheroidal aggregates; at Liege, Belgium. Kootenai series Part of the Comanchean, of the continental facies, including coal seams, occurring in western Canada. CTD Korfmann arch saver A machine for withdrawing steel arches by means of a controlled hydraulic system instead of drawing them by hand or winches. Nelson Korfmann power loader A double-ended cutter loader; i.e., it can cut and load in both directions. It consists of four milling heads and one cutter chain surrounding them; guided by armored conveyor; rope-hauled; cuts at 2.3 ft/s (0.7 m/s) and flits at 10 ft/s (3.0 m/s). The minimum workable seam thickness is 26 in (66 cm) on gradients from 0 degrees to 12 degrees ; maximum length of face is 165 yd (151 m); takes 3-1/2 ft (1.07 m) per cut, continuous mining. Nelson kornelite A monoclinic mineral, Fe2 (SO4 )3 .7H2 O ; forms rose to violet prisms; an alteration of pyrite. kornerupine An orthorhombic mineral, Mg4 (Al,Fe)6 (Si,B)4 O21 (OH) ; forms columnar crystals with prismatic cleavage; in high-grade metamorphic aluminous rocks. 1722

korzhinskite A mineral, CaB2 O4 .H2 O ; in skarns with other calcium borate minerals. koettigite A monoclinic mineral, Zn3 (AsO4 )2 .8H2 O ; vivianite group; forms a series with parasymplesite; carmine-red with one perfect cleavage; occurs with smaltite at Schneeberg, Saxony, Germany. Also spelled koettigite. kotulskite A hexagonal mineral, Pd(Te,Bi) . Kotze konimeter A dust-sampling instrument consisting of an air cylinder and piston actuated by a spring, and so arranged that on release of the piston a known volume of air is impinged at high velocity against a plate coated with vaseline. The dust spot so produced is examined under the microscope, and a count is made of the number of particles. Greenburg Kourbatoff's reagent An etchant for steel; it consists of seven parts of a solution containing 20% methyl alcohol, 20% ethyl alcohol, 20% iso-amyl alcohol, and 10% butyl alcohol added to three parts of a solution of 4% nitric acid in acetic anhydride. This etchant colors sorbite and troostite, leaving the other constituents unaffected. Osborne koutekite A hexagonal mineral, Cu5 As2 . kramerite See: probertite krantzite A fossil resin resembling amber and found in small yellowish grains disseminated in brown coal. Tomkeieff kratochvilite An orthorhombic mineral, C13 H10 . 1723

kraurite See: dufrenite krausite A monoclinic mineral, KFe(SO4 )2 .H2 O ; forms soft yellowish-green prismatic crystals and crusts. kremersite An orthorhombic mineral, (NH4 ,K)2 FeCl5 .H2 O; forms red pseudo-octahedra around fumaroles in Sicily, Italy. krennerite One of the gold telluride group of minerals, (Au,Ag)Te2 ; corresponds to the same general formula as sylvanite and calaverite. Silver-white to pale yellow color; sp gr, 8.35. Found in Colorado and Romania. Syn: white tellurium kriging a. A weighted, moving-average interpolation method in which the set of weights assigned to samples minimizes the estimation variance, which is computed as a function of the variogram model and locations of the samples relative to each other, and to the point or block being estimated. b. In the estimation of ore reserves by geostatistical methods, the use of a weighted, moving-average approach both to account for the estimated values of spatially distributed variables, and also to assess the probable error associated with the estimates. SME, 1 kriging standard deviation The standard error of estimation computed for a kriged estimate. By definition, kriging is the weighted linear estimate with the particular set of weights that minimizes the computed estimation variance (standard error squared). The relationship of the kriging standard deviation to the actual error of estimation is very dependent on the variogram model used and the validity of the underlying assumptions; therefore, kriging standard deviations should be interpreted with caution. Krohnke process The treatment of silver ores preparatory to amalgamation, by humid chloridization with copper dichloride. Fay kroehnkite 1724

A monoclinic mineral, Na2 Cu(SO4 )2 .2H2 O ; azure; in Chilean copper deposits. Also spelled kroehnkite. Kroll process Process in which purified titanium tetrachloride is reduced to the metallic state with magnesium in an inert atmosphere of helium or argon. Krupp process a. See: Krupp washing process Fay b. A cementation process designed for the hardening of surface steel, as for armor plates, where the object is to strengthen the outer portion of the mass from the surface toward the interior. Standard, 2 Krupp-Renn The process for the production of iron and steel from medium-grade ores, such as those containing 44% to 57% iron and having a high silicon content. The process involves a continuous reduction and is carried out in a revolving tube furnace, which is designed for the production of iron. The iron is reduced into a sponge and then converted into lowcarbon metallic grains, which are called pellets. Krupp washing process The removal of silicon and phosphorus from molten pig iron by running it into a Pernot furnace lined with iron oxides. Iron ore may also be added, and the bath is agitated by rotation for 5 to 8 min only. See: Krupp process Fay kryptomere See: aphanite kryzhanovskite An orthorhombic mineral, MnFe2 (PO4 )2 (OH)2 .H2 O ; an oxidation product of phosphoferrite; forms a series with garyansellite. K-spar See: potassium feldspar K.T.A.M. auger tube See: K.T.A.M. double-tube auger. 1725

K.T.A.M. double-tube auger A double-tube soil-sampling device designed to be rotated by hand to obtain soil samples from relatively shallow depths. The inner tube is a swivel type, and its cutting end leads the bottom of the spiral on the outside of the outer tube. Long kua Specially shaped hoe used for working gravel in the sluice in Japan. Fay kulm See: culm kundaite A variety of grahamite from Estonia. Distinguished by the brown color of its powder and its greater solubility in turpentine and chloroform. English; Tomkeieff kunkur See: kankar kunzite A gem variety of spodumene; lilac, transparent. Syn: lithia amethyst kupferschiefer A dark-colored shale once worked for copper in Germany. kupletskite A triclinic mineral, (K,Na)3 (Mn,Fe)7 (Ti,Nb)2 Si8 O24 (O,OH)7 ; astrophyllite group; forms series with astrophyllite and with cesium kupletskite. kuprojarosit See: cuprojarosite kurnakovite A triclinic mineral, MbB3 O3 (OH)5 .5H2 O ; dimorphous with inderite. kuroko 1726

In Japan, black ore. The kuroko deposits consist of intimately mixed zincblende, galena, and barite, associated (in places) with large masses of pyrite and gypsum. Hess kurtosis In statistics, the technical name describing peakedness of a frequency distribution. It is statistically measured as the coefficient of quartile kurtosis. kutnohorite A trigonal mineral, 2[Ca(Mn,Mg,Ca,Fe)(CO3 )2 ] ; dolomite group; in carbonate veins. Also spelled kutnahorite. kyack A packsack to be swung on either side of a packsaddle. Webster 3rd kyanite A triclinic mineral, 4[Al2 SiO5 ] ; trimorphous with andalusite and sillimanite; in blades that are distinctly harder across than along; a common rock-forming mineral in schist and gneiss. Also spelled cyanite. Syn: disthene; sappare. kyanophyllite A mixture of paragonite plus muscovite. kyrosite A variety of marcasite. Syn: white copper ore

L labeled atom Atom rendered radioactive and thus traceable through a chemical process or a flow line. Also called tagged atom. Pryor, 3 labile Said of rocks and minerals that are mechanically or chemically unstable; easily decomposed. CF: unstable 1727

labile protobitumens Easily decomposable plant and animal products such as fats and oils or proteins that are found in peat and sapropels. Tomkeieff lability The property of bituminous emulsions, relating to the ease with which they break when put into use. Labile emulsions are quick breaking. Nelson labor a. A shaft, cavity, or other part of a mine from which ore is being or has been extracted; a working, as a labor in a quicksilver mine. See also: working b. The annual assessment work required on claims calls for $100.00 of labor and improvements. In Australia, claims have continuous labor or are manned throughout the year. von Bernewitz c. A Spanish term used in early land surveys in Texas for unit of area equal to about 177.14 acres (representing a tract 100 varas square). Pronounced la-bore. AGI laboratory In the iron and steel industry, the space between the fire and flue bridges of a reverberatory furnace in which the work is performed. Also called "kitchen and hearth." Fay La Bour centrifugal pump A self-priming centrifugal pump containing a trap, which always ensures sufficient water for the pump to function, and also a separator to remove the entrained air in the water. Lewis labradorescence Optical diffraction of monochromatic light, commonly blue, caused by exsolution lamellae in some labradorite samples; appears to come from within the sample. CF: labrador moonstone labrador hornblende See: orthopyroxene labradorite

1728

A triclinic mineral, (Ca,Na)[(Al,Si)AlSi2 O8 ] ; CaAl 70 to 50 mol % and NaSi 30 to 50 mol %; plagioclase series of the feldspar group; a common rock-forming mineral in basalt, gabbro, and anorthosite; also in hornfels and siliceous marble. Labrador moonstone A variety of labradorite displaying an internal play of colors. See: labradorescence Labrador rock See: labradorite labuntsovite A monoclinic mineral, (K,Ba,Na)(Ti,Nb)(Si,Al)2 (O,OH)7 .H2 O . Also spelled labuntzovite; labountsovite. labyrinth a. A series of canals through which a stream of water is directed for sorting crushed ore according to its specific gravity. Fay b. A pipe or chamber of many turnings, for condensing metal vapors or fumes. Standard, 2 laccolite See: laccolith laccolith A concordant igneous intrusion with a known or assumed flat floor and a postulated, dikelike feeder commonly thought to be beneath its thickest point. It is generally planoconvex in form and roughly circular in plan, less than 5 miles (8 km) in diameter, and from a few feet to several hundred feet in thickness. See also: phacolith AGI lace Eng. Line cut, with the point of a pick, on slickensides. lacing a. The timber or other material placed behind and around the main supports. See also: lagging; lofting. Nelson b. Strips or light bars of wrought iron bent over at the ends and wedged between the bars and the roof. Fay c. Small boards or patches that prevent dirt from entering an excavation through spaces between sheeting or lagging planks. Nichols, 1 d. Bars placed diagonally to space and stiffen members, as in a built-up column. 1729

Crispin e. Eng. Wood placed inside the sets of timber as a tie from prop to prop. Also called stringing piece. See also: bracing f. N. Staff. Timbers placed across the tops of bars or caps to secure the roof between the timbers. Fay lack clay Ire. A thin pan under the moors. Arkell LaCoste-Romberg gravimeter A long-period vertical seismograph suspended system adapted to the measurement of gravity differences. Sensitivity is achieved by adjusting the system to proximity to an instability configuration. AGI lacroixite A monoclinic mineral, NaAl(PO4 )F ; isostructural with durangite; in cavities in granite pegmatites. lactic acid In flotation, a depressant sometimes used to depress iron minerals. Pryor, 3 lacustrine Pertaining to, formed in, growing in, or inhabiting lakes. ladder a. The arm that carries the tumblers and bucket line of a dredge. Fay b. The continuous line of mud buckets, carried on an oblique endless chain, in a bucket ladder excavator or dredger. CTD c. The digging boom assembly in a hydraulic dredge or chain-and-buckets ditcher. Nichols, 1 ladder-bucket dredge See: bucket-ladder dredge ladder ditcher An excavator that digs ditches by means of a chain of traveling buckets supported by a boom. ladder drilling 1730

Arrangement used in large-scale rock tunneling. Retractable drills with pneumatic power legs are mounted on prefabricated steel ladders in tiers, connected into a holding frame or jumbo. As many as 22 drills can be worked simultaneously by a small labor force. Pryor, 3 ladder lode See: ladder vein ladder sollar A platform at the bottom of each ladder in a series. Standard, 2 ladder vein One of a series of mineral deposits in transverse, roughly parallel fractures that have formed along foliation planes perpendicular to the walls of a dike during its cooling or along shrinkage joints in basaltic rocks or dikes. Syn: ladder lode ladderway a. See: manway b. Mine shaft, raise, or winze between two main levels, equipped with ladders. Pryor, 3 c. The particular shaft or compartment of a shaft containing ladders. Also called ladder road. Fay lade a. Scot. A load. b. A watercourse, ditch, or drain. c. The mouth of a river. laded metal Molten glass dipped from a melting pot to a casting table. Also called gathered metal. Standard, 2 lading hole In glassmaking, an orifice through which melted glass is ladled or taken out by a cuvette. Standard, 2 ladle a. In a smelter or foundry, a steel-holding vessel used in the transfer and transport of molten metal, matte, or slag. Pryor, 3 b. A long-handled, cup-shaped tool for ladling glass out or from one spot to another. Also used for filling open pots. ASTM 1731

ladle addition In foundry work, addition of special metals (e.g., granulated nickel) or compounds (e.g., ferrosilicon) to molten iron in ladle to produce special qualities in castings. Pryor, 3 ladle craneman In the iron and steel industry, a person who places ladles under the tapholes of furnaces and holds them in position while the metal is poured into them. Also called charging floor crane operator; ladle crane operator; steel charger. DOT ladle filler In metallurgy, a person who transfers molten metal from the furnace into a ladle and skims and fluxes metal preparatory to casting. DOT ladle furnace A small furnace for calcining or melting substances in a ladle. Standard, 2 ladle liner In ore dressing, smelting, and refining, a person who repairs and relines pouring ladles used to transport molten metals, such as iron, steel, and copper. Also called ladle cleaner; ladle dauber; ladle houseman; ladle mender; ladle patcher; ladle repairman. DOT ladle lip A concave projection at the upper edge of a ladle to guide the metal in pouring. Mersereau, 2 ladler Worker who pours molten glass from a suspended ladle on casting table for rolling into sheet glass. DOT Lafond's tables A set of tables and associated information for correcting reversing thermometers and computing dynamic height anomalies; compiled by E.C. Lafond and published by the U.S. Navy Hydrographic Office as H.O. Pub. No. 617. Hunt lag

1732

a. To place planks, slabs, or small timbers over horizontal, or behind upright, members of mine timber sets to form a ceiling or wall. Long b. In flotation, any retardation of an output with respect to the causal input. Fuerstenau c. A flattish piece of wood or other material to wedge the timber or steel supports against the ground and to secure the area between the supports. See also: lid; wedge. Nelson d. To protect a shaft or level from falling rock by lining it with timber (lagging). CTD e. Time required for circulation liquid to travel downward from the drill pump through the drill string to the bit or upward from the bottom of the borehole to the collar. Long f. The lapse of time between the occurrence of an event or condition and its detection on a recording device. Long g. To provide or cover with lags; as, to lag a boiler with a nonconductor; to lag timbers in a mine. See also: lags; lagging. Standard, 2; Fay h. A distance class interval used for variogram computation. lag deposit See: lag gravel lagergestein Ger. The enclosed pieces of older rocks in a sedimentary ore deposit. Schieferdecker lag fault An overthrust, the thrusted rocks of which move differentially so that the upper part of the geologic section is left behind; the replacement of the upper limb of an overturned anticline by a fold fault. Syn: tectonic gap lagged liner A metal plate with raised areas, to be inserted in the bottom of shaker conveyor troughs and held in place by spot welding. The raised areas assist coal travel on steep grades or under wet conditions. Jones, 1 lagging a. Lagging wedges and secures the roof and sides behind the main timber or steel supports in a mine and provides early resistance to pressure. If concrete slabs are used, they are made in lengths to fit between the arch webs. The lagging behind steel arches in tunnels may be pyrolith-treated, fire-resisting boards. Also called lacing. Nelson b. Pieces of timber about 4 ft 6 in by 6 in by 2 in (1.4 m by 15 cm by 5 cm) with one end sharpened or beveled to give the lath an upward trend when being driven into the roof gravels. A number of laths driven into the roof form a protective shield for the miners working in the face. Sometimes called laths. Eng. Min. J., 1 c. In shafts, planks, usually 2 in, placed on the outside of sets. Coeur D'Alene lagging has 2-in by 2-in cleats nailed to the top and bottom of the wall and end plates about 2 in back from the outer edge. The 1733

lagging is then cut to fit between the plates and is placed against the cleats and flush with the plates on the outside. Lewis d. Narrow boards, generally planed, placed horizontally on the arch frames of a center. On this lagging the arch of masonry is built. The term is also applied to poling boards. Stauffer e. Planks, slabs, or small timbers placed over the caps or behind the posts of the timbering, not to carry the main weight, but to form a ceiling or a wall, preventing fragments or rock from falling through. See also: lag f. Heavy planks or timbers used to support the roof of a mine, or for floors of working places, and for the accumulation of rock and earth in a stope. Fay g. Long pieces of timbers closely fitted together and fastened to the drum rings to form a surface for the rope to wind on. Fay h. The narrow strips supporting an arch of masonry while in construction. Standard, 2 i. The surface or contact area of a drum or flat pulley, esp. a detachable surface or one of special composition. Nichols, 1 j. Boards fastened to the back of a shovel for blast protection. Nichols, 1 k. Covering on boilers, tanks, and pipes used to provide thermal insulation. Pryor, 3 l. Material applied to pulleys to increase traction between the pulley and belt and to decrease wear on both. See also: backing deals m. Verb. To install lagging. AGI lagging bar See: roof stringer lag gravel a. A residual accumulation of rock fragments remaining on a surface after the finer material has been blown away by winds. See also: desert pavement; pebble armor. AGI b. Coarse-grained material that is rolled or dragged along the bottom of a stream at a slower rate than the finer material, or that is left behind after currents have winnowed or washed away the finer material. Syn: lag; lag deposit. AGI lagre Fr. In sheet glass manufacture, a sheet of perfectly smooth glass, interposed between the flattening stone and the cylinder that is to be flattened. Standard, 2 lags Eng. Long pieces of timber closely fitted together and fastened to oak curbs or rings forming part of a drum used in sinking through quicksand or soft ground. CF: lag lag screw a. A square-headed, heavy wood screw. It must be tightened down with a wrench because its head is not slotted. Crispin b. A flat-headed machine screw by which to fasten wood lagging, as on a curve surface. Standard, 2 1734

lag time The total time between the initial application of current and the rupture of the circuit within the detonator. BS, 12 lahar See: mudflow laihunite Black monoclinic mineral, Fe2+ Fe23+ (SiO4)2 . lair Clay; mud; mire. Arkell laitakarite A trigonal mineral, Bi4 (Se,S)3 . Syn: selenjoseite lake-bed placer In Alaska, a placer in the bed of a present or ancient lake; generally formed by landslides or glacial damming. Lake copper Copper produced from the Lake Superior ores in which the metal occurs native and is of high purity. CTD Lake George diamond See: Herkimer diamond lake ore a. See: bog iron; bog iron ore. b. A disklike or irregular concretionary mass of ferric oxyhydroxide less than 1 m thick; or a layer of porous, yellow bedded limonite formed along the borders of certain lakes. See also: bog ore Lake Superior agate a. Any agate from the Lake Superior region. b. Thompsonite marked or banded like agate from the Lake Superior region. 1735

Lake Superior greenstone See: pumpellyite lambda plate See: mica plate Lambert's Law See: translucency lamella A thin scale, leaf, lamina, or layer; e.g., one of the units of a polysynthetically twinned mineral, such as plagioclase. Plural, lamellae. AGI lamellar Composed of or arranged in lamellae; disposed in layers like the leaves of a book. Syn: lamellate lamellar flow Flow of a liquid in which layers glide over one another. CF: laminar flow lamella roof A vault or large span built up with short structural members of timber or pressed steel, joined together in a diamond pattern by bolting or other suitable connections. This system, which is a type of stressed-skin construction, was patented in 1925 by a German engineer. Hammond lamellar pyrite See: marcasite lamellar stellate In mineralogy, having or consisting of lamellae arranged in groups resembling stars. Standard, 2 lamellar twinning Multiple parallel twins; e.g., albite twinning in plagioclase. Syn: polysynthetic twinning 1736

lamellate See: lamellar lame-skirting Widening a passage by cutting coal from the side of it. Also called skipping; slicing. Fay lamina The thinnest recognizable layer in a sedimentary rock. Plural, laminae. CF: stratum laminar flow Water flow in which the stream lines remain distinct and the flow direction at every point remains unchanged with time. It is characteristic of the movement of ground water. CF: turbulent flow; lamellar flow. Syn: streamline flow; sheet flow. AGI laminar velocity That velocity below which, in a particular conduit, laminar flow will always exist, and above which the flow may be either laminar or turbulent, depending on circumstances. Also known as lower critical velocity. Seelye, 1 laminated In very thin parallel layers. laminated iron Iron in the form of thin sheets; used as cores of transformers, etc. The losses due to eddy currents with laminated iron cores are lower when compared with solid cores. Nelson laminated quartz Vein quartz containing slabs, blades, or laminar films of other material. AGI laminating machine A set of rolls or any apparatus for making thin plates of metal, such as gold, preliminary to beating. Standard, 2 laminating roller

1737

The adjustable roller in a rolling mill whereby the thickness of rolled metal sheets is regulated. Standard, 2 lamination a. The formation of a lamina or laminae. AGI b. The state of being laminated; specif. the finest stratification of bedding, typically exhibited by shales and fine-grained sandstones. AGI c. A laminated structure. AGI laminations Of rocks, bedding in layers less than 1 cm thick; formation with thin layers that vary in grain or composition. Pryor, 3 lamings a. Partings in coal seams. Arkell b. N. of Eng. A collier's term for accidents of almost every description to people working in and about the mines. A variation of lame, to cripple or disable. Fay lamp a. See: safety lamp b. A small handheld electrical device that produces an intense ultraviolet radiation, called "black light." See: black light; fluorescent lamp. Long c. An electrical lamplike device producing intense ultraviolet radiations for visually examining drill cores or rock specimens for the presence and/or abundance of fluorescent minerals. Long lampadite Wad containing 4% to 18% copper oxide and commonly cobalt. Syn: cupreous manganese lamp cabin a. A place above ground where the safety and cap lamps are maintained, before being handed to the workers. b. See: lamp room lamp cleaner See: lampman lamp cup

1738

A means for supporting a flame safety lamp on a tripod to provide a sight for surveying. BS, 7 lamp house See: lamp cabin lamping In prospecting, use of a portable ultraviolet lamp to reveal fluorescent minerals. Pryor, 3 lamp keeper See: lampman lampman a. The person in charge of the lamp room at a mine responsible for the maintenance of the safety lamps. Nelson b. In mining, one who cleans, tests, and repairs lamps used underground by miners. Also called battery charger; lamp cleaner; lamp-house man; lamp keeper; lamp repairer; safety-lamp keeper. DOT lamp rack A rack upon which electric cap lamp batteries are placed to be charged. lamp repairer See: lampman lamprobolite See: oxyhornblende lamproite A group name for dark-colored hypabyssal or extrusive rocks rich in potassium and magnesium; also, any rock in that group, such as madupite, orendite, fitzroyite, verite, cedricite, or wyomingite. AGI lamp room A room or building at the surface of a mine provided for charging, servicing, and issuing all cap, hand, and flame safety lamps held at the mine. See also: self-service system 1739

lamprophyllite A monoclinic mineral, Na2 (Sr,Ba)2 Ti3 (SiO4 )4 (OH,F)2 . Syn: molengraafite lamprophyre A group of dark-colored, porphyritic, hypabyssal igneous rocks characterized by panidiomorphic texture, a high percentage of mafic minerals (esp. biotite, hornblende, and pyroxene), which form the phenocrysts, and a fine-grained groundmass with the same mafic minerals in addition to feldspars and/or feldspathoids; also, any rock in that group. Most lamprophyres are highly altered. They are commonly associated with carbonatites. CF: leucophyre lamprophyric Said of the holocrystalline-porphyritic texture exhibited by lamprophyres, in which phenocrysts of mafic minerals are contained in a fine-grained crystalline groundmass. AGI lamproschist Metamorphosed lamprophyre with a schistose structure containing brown biotite and green hornblende. AGI lamp station a. Fixed places in the intake airway of a coal mine where the miners' safety lamps are externally examined by a deputy before the workers proceed to their working places. In a safety lamp mine, the lamp station is the only place where flame safety lamps may be opened and relighted. Nelson b. Locations in gaseous mines where safety lamps are opened, cleaned, and refilled or charged by a qualified attendant. Hudson c. A place underground, appointed for the examination, by an official, of safety lamps in use. BS, 13 d. A lamp room. Fay Lanarkian A subdivision of the Coal Measures--based mainly on plant fossils. It represents in part, the millstone grit of South Wales; well developed in South Scotland, where coal seams are present. Nelson lanarkite A monoclinic mineral, Pb2 (SO4 )O ; perfect basal cleavage; named for Lanarkshire, Scotland. 1740

Lancashire bord-and-pillar system See: bord-and-pillar method Lancashire method A method of working moderately inclined coal seams. The first stage consists of splitting a panel of coal into pillars and as a second stage the pillars are extracted on the retreat by a longwall face. Nelson lanchut A short sluice used for cleaning tin concentrate. Hess land a. To set or allow the bottom end of a drivepipe or casing to rest at a preselected horizon in a borehole. Long b. For reamers, drills, and taps, the solid section between the flutes. ASM, 1 land accretion Reclamation of land from the sea or other low-lying or flooded areas by draining and pumping, dumping of fill, or planting of marine vegetation. AGI land chain A surveyor's chain of 100 links. land compass A surveyor's compass. lander a. A worker stationed at one of the levels of a mine shaft to unload rock from the bucket or cage and load drilling and blasting supplies to be lowered to the crew. Webster 3rd b. In the quarry industry, one who supervises and assists in guiding, steadying, and loading, on trucks or railroad cars, blocks of stone hoisted from the quarry floor. Syn: top hooker c. In metal mining, a laborer who (1) cleans skips by directing a blast of compressed air into them through a hose; (2) records number of loaded skips hoisted to surface; and (3) loads railroad cars with ore from bins by raising and lowering chute doors. DOT d. In anthracite coal mining, bituminous coal mining, or metal mining, one who works with shaft sinking crew at top of shaft or at a level immediately above shaft bottom, dumping rock into mine cars from a bucket in which it is raised. Also called bucket dumper; 1741

landing tender; top lander. DOT e. Eng. The person who receives the loaded bucket or tub at the mouth of the shaft. Also called banksman. Fay landerite A pink or rose variety of grossular in dodecahedra. Syn: rosolite; xalostocite. landesite An orthorhombic mineral, (Mn,Mg)9 Fe3 (PO4 )8 (OH)3 .9H2 O . landform Any physical, recognizable form or feature of the Earth's surface, having a characteristic shape, and produced by natural causes; it includes major forms such as plain, plateau, and mountain, and minor forms such as hill, valley, slope, esker, and dune. Taken together, landforms make up the surface configuration of the Earth. Syn: relief feature landform system A group of related natural features, objects, or forces; e.g., a drainage system or a mountain system. See also: mountain system landing a. The top or bottom of a slope, shaft, or inclined plane. Fay b. The mouth of a shaft where the cages are unloaded; any point in the shaft at which the cage can be loaded with people or materials. Nelson c. The brow or level section at the top of an inclined haulage plane where the loaded tubs are exchanged for empty tubs, or vice versa. See also: apex d. A preselected and prepared horizon in a borehole on or at which the bottom end of a drivepipe or casing string is to be set. Long e. A platform from which to charge a furnace. Standard, 2 f. Level stage in a shaft at which cages are loaded and discharged. Pryor, 3 landing box Scot. The box into which a pump delivers water. Fay landing shaft S. Wales. A shaft through which coal is raised. Fay landing tender See: lander 1742

land pebble See: land-pebble phosphate land-pebble phosphate A term used in Florida for a pebble phosphate occurring as pellets, pebbles, and nodules in gravelly beds a few feet below the ground surface. It is extensively mined. Syn: land pebble; land rock; matrix. AGI land plaster Finely ground gypsum used as a fertilizer. land rock A syn. used in South Carolina for land-pebble phosphate. AGI Landsat Multispectral data from satellite remote sensing imagery that provides landscape patterns reflecting geologic structures, types of rocks, and vegetation. SME, 1 landscape agate See: moss agate landscape marble A close-grained limestone characterized by dark conspicuous dendritic markings that suggest natural scenery (woodlands, forests); e.g., the argillaceous limestone in the Cotham Marble near Bristol, England. Syn: forest marble landslide A general term covering a wide variety of mass-movement landforms and processes involving the downslope transport, under gravitational influence, of soil and rock material en masse. Usually the displaced material moves over a relatively confined zone or surface of shear. The wide range of sites and structures, and of material properties affecting resistance to shear, result in a great range of landslide morphology, rates, patterns of movement, and scale. Landsliding is usually preceded, accompanied, and followed by perceptible creep along the surface of sliding and/or within the slide mass. Terminology designating landslide types generally refers to the landform as well as the process responsible for it; e.g., rockfall, translational slide, block glide, avalanche, mudflow, liquefaction slide, and slump. Syn: landsliding; slide; landslip. AGI 1743

landsliding See: landslide landslip A British syn. of landslide. AGI land subsidence See: subsidence lands valuable for minerals As used in the mining law, applies to all lands chiefly valuable for nonmetalliferous deposits, such as alum, asphaltum, borax, guano, diamonds, gypsum, marble, mica, slate, amber petroleum, limestone, and building stone, rather than for agricultural purposes. Such lands are subject to disposition by the United States under the mining laws only. Ricketts land weight Lanc. The pressure exerted by the subsidence of the cover or overburden. Lane mill A slow-speed roller mill of the Chilean type. A horizontal spider carrying six rollers revolves slowly in a pan 10 ft (3 m) or more in diameter, making about 8 rpm. Liddell langbanite A trigonal mineral, (Mn,Ca)4 (Mn,Fe)9 SbSi2 O24 ; in skarns. Also spelled laangbanite. (Not langbeinite.) langbeinite An isometric mineral, K2 Mg2 (SO4 )3 ; associated with halite and sylvite in marine evaporite deposits; a source of potash. (Not langbanite.) langite A monoclinic mineral, Cu4 (SO4 )(OH)6 .2H2 O ; in blue-green concretionary crusts; in Cornwall, U.K., and Stredoslovensky, Slovakia. lang lay rope 1744

A rope in which the wires are twisted in the same direction as the strands and the wires are thus exposed to wear for a much greater length than in round rope. The smoother lang lay resists wear to better advantage and is frequently preferred for haulage ropes. Syn: universal lay rope Lewis; Sinclair, 5 Langmuir's adsorption isotherm The equation for calculating a gas monolayer on a flat surface. Pryor, 3 Langmuir trough Rectangular tank used to measure the surface tension of a monolayer adsorbed at the surface of a liquid. Pryor, 3 Lang's lay rope See: winding rope lansfordite A monoclinic mineral, MgCO3 .5H2 O ; forms small stalactites that alter to nesquehonite in mines near Lansford, PA. lantern Enclosed light (candle or oil) carried by a mine worker. Hess lanthanite An orthorhombic mineral, (Ce,La,Nd)2 (CO3 )3 .8H2 ) ; further speciated according to its predominant rare-earth element; in pegmatites and carbonate-rich sediments. lanyon shield An iron curtain, stiffened by ribs of angle iron, suspended from trolley wheels running on a rail parallel with and in front of a furnace to protect the worker from the furnace heat. Fay lap a. One coil of rope on the winding drum of the mine hoist. Pryor, 3 b. Polishing cloth used in preparing polished mineral specimens by abrasive grinding. Pryor, 3 c. A surface defect, appearing as a seam, caused by folding over hot metal, fins, or sharp corners and then rolling or forging them into the surface, but not welding them. ASM, 1 d. To dimension, smooth, or polish (as a metal surface or body) to a high degree of 1745

refinement or accuracy. Webster 3rd e. An imperfection; a fold in the surface of a glass article caused by incorrect flow during forming. ASTM f. A tool used for polishing glass. ASTM g. A rotating disk of soft metal or wood, used to hold polishing powder for cutting or polishing gems or metal. laper Impure sandy green limestone with shaly partings in the Middle Purbeck beds, Swanage, U.K. Also spelled leaper; leper. lapidary a. An artificer who cuts, polishes, or engraves gems or precious stones. b. Person who is skilled in the nature and kind of gems or precious stones; a connoisseur of lapidary work. lapilli Pyroclastics that may be either essential, accessory, or accidental in origin, of a size range that has been variously defined within the limits of 2 mm and 64 mm. The fragments may be either solidified or still viscous when they land (though some classifications restrict the term to the former); thus there is no characteristic shape. An individual fragment is called a lapillus. CF: cinder lapilliform Having the form of small stones. lapis lazuli a. A lazurite-bearing rock; contains lazurite or hauyne (possibly zeolitized), diopside, edenitic amphibole (koksharovite), muscovite, calcite, and pyrite; occurs in various shades of blue; possibly the original sapphire of the ancients; Syn: azure; lazuli. b. Gemquality lazurite. (Not lazulite.) c. An ultramarine-colored serpentine in India. See also: ultramarine lapis matrix Lapis lazuli (lazurite) containing prominent patches of calcite. See also: Chilean lapis; lazurite. LaPointe picker Miniature belt conveyor, on which small ore particles move singly past a Geiger-Mueller tube that is set to operate a sorting device. This removes from the passing stream each 1746

particle of radioactive ore that reaches the required intensity, therefore sorting out the valuable material. Pryor, 3 lapped a. Overlapped and fitted together. Nichols, 1 b. The act of polishing or grinding on a lap. Laramide orogeny A time of deformation, typically recorded in the eastern Rocky Mountains of the United States, whose several phases extended from late Cretaceous until the end of the Paleocene. It is named for the Laramie Formation of Wyoming and Colorado, probably a synorogenic deposit. AGI Laramide revolution See: Laramide orogeny lardalite See: laurdalite larderellite A monoclinic mineral, (NH4 )B5 O6 (OH)4 . lardite a. White hydrated silica, probably a variety of opal; occurring in clay in central Russia. b. Massive talc. Syn: steatite; agalmatolite. c. A massive variety of muscovite and/or pyrophyllite. See also: pagodite lard oil An oil produced from animal fats. This oil is an efficient lubricant for use on metalcutting tools. Crispin lardstone Massive talc; steatite. lard stone A kind of soft stone found in China. See also: steatite; agalmatolite. Fay 1747

large Eng. The largest lumps of coal sent to the surface, or all coal that is handpicked or does not pass over screens; also the largest coal that passes over screens. Fay large coal a. One of the three main size groups by which coal is sold by the National Coal Board of Great Britain. Large coal has no upper size limit and has a lower size limit of 1-1/2 to 2 in (3.8 to 5.1 cm) and embraces large screened coal, cobbles, and treble sizes. See also: graded coal; smalls. Nelson b. Coal above an agreed size without any upper size limit. Also called lump coal. BS, 5 large colliery Gr. Brit. In general, a colliery producing more than 1,500 st/d (1,360 t/d). Nelson large-diameter boring machine An auger-type coal-cutting machine developed by the U.S. Bureau of Mines for use in anthracite mining. It can drill holes 1 ft (31 cm) in diameter, 300 ft (91 m) long, and larger holes for shorter distances. large knot A large knot is one whose average diameter exceeds one-third the width of the surface on which it appears; but such a knot may be allowed if it occurs outside the sections of the mine track tie between 6 in and 18 in (15 cm and 46 cm) from each end. large shake A large shake is one that exceeds one-third the width of the mine track tie. A shake not exceeding this limitation and that does not extend nearer than 1/2 in (1.3 cm) to any surface shall be permissible. large split A term applying to mine track ties. A large split is a split exceeding 5 in (13 cm) in length. Splits not longer than 5 in are permissible providing satisfactory antisplitting devices have been properly applied. larnite A monoclinic mineral, 4[beta-Ca2 SiO4 ] ; gray; in contact metamorphosed limestone. CF: bredigite 1748

larsenite An orthorhombic mineral, PbZnSiO4 ; forms colorless to white prisms; in veins at Franklin, NJ. Larsen's pile A type of pile consisting of hollow cylinders that increase resistance against bending and crumpling. They are esp. useful in shaft sinking in sand and gravel. Stoces Larsen's spiles Steel sections of various forms, made esp. to resist bending, that are used in place of wooden spiles in forepoling. Stoces Larson ledge finder A tool used to reach bedrock when the driven pipe has failed. larvikite An alkalic syenite, grading to monzonite, composed of phenocrysts of two feldspars (esp. oligoclase and alkali feldspar), often intimately intergrown, which comprise up to 90% of the rock, with diopsidic augite and titanaugite as the chief mafic minerals, and accessory apatite (generally abundant), ilmenite, and titaniferous magnetite, and less commonly olivine, bronzite, lepidomelane, and quartz or feldspathoids (less than 10% by volume). Its name, given by Broegger in 1890, is derived from Larvik, Norway. Also spelled laurvikite. Syn: blue granite AGI laser An active electron device that converts input power into a very narrow, intense beam of coherent visible or infrared light; the input power excites the atoms of an optical resonator to a higher energy level, and the resonator forces the excited atoms to radiate in phase. Derived from "light amplification by stimulated emission of radiation." See also: maser lash To attach a chain to a haulage rope by wrapping or lapping the end of the chain around the rope, the other end being attached to a mine wagon. Mason lasher a. A native employed to do lashing. See also: lashing b. See: mucker 1749

lasher-on A person employed to lash the chains from the tubs to the endless rope, in underground mechanical haulage. CTD lashing a. Any of a number of planks nailed inside of several frames or sets in a shaft to keep them in place. Also called listing. Webster 2nd b. A binding, generally of light line around the end of a rope. c. In South Africa, loading broken rock or ore with shovels. Nelson d. Shoveling rock downstope to ore passes--work performed by a lasher. A "lasher-on" connects tubs or trucks to a rope haulage. Also called mucking. Pryor, 3 lashing chain A short chain to attach tubs to an overrope in endless rope haulage by wrapping it around the rope. The chain may be about 12 ft (3.7 m) long, of low manganese steel, with 3/8in-diameter (9.5-mm-diameter) standard links. At one end of the chain, a ring 4 in (10.2 mm) in diameter is attached to the drawbar hook of the tub, and to a hook about 3/8 in in diameter to secure it to the rope at the lashing end. On an undulating road, two lashing chains may be necessary--one forward and one rear of the tub. Nelson lash-up Extemporized engineering rig for a temporary job. Pryor, 1 lasque A thin, flat diamond with a simple facet at the side; used by Indian cutters to cover miniature paintings. Also spelled lask. Also called portrait stone. last lift N. of Eng. The last rib or jud to come off a pillar. Fay latch a. The locking device on a hoist hook, elevator, lifting bail, etc. Long b. The inner-tube locking and unlocking device in the head of a wire-line core barrel. Long latches a. Applied to the split rail and hinged switches. Syn: switch Fay b. Hinged switch points, or short pieces of rail that form rail crossings. Fay 1750

late magmatic mineral A mineral formed during the late stages of magmatic activity, between the main stage of crystallization and the pegmatitic stage. latent heat Thermal energy absorbed or emitted in a process (as fusion or vaporization) other than change of temperature. CF: sensible heat Webster 3rd latent heat of fusion The amount of heat required to change 1 g of a substance at the temperature of its melting point from the solid to the liquid state without changing temperature. Morris lateral a. A hard heading that branches off a horizon, in horizon mining, along the strike of the seams. It may be from 14 to 20 ft (4.3 to 6.1 m) wide. At intervals of 1,000 to 1,500 yd (910 to 1,400 m) along the lateral, crosscut roads are driven at right angles to intersect and develop the coal seams. From the crosscuts, conveyor panels are opened out in the seams. In general, the term lateral is also applied to any coal heading driven in a sideways direction. Nelson b. Belonging to the sides, or to one side. Fay c. A horizontal mine working. Fay d. Situated on or at, or pertaining to, a side. CTD e. A conduit diverting water from a main conduit, for delivery to distributaries. Seelye, 1 f. A secondary ditch. Seelye, 1 lateral cleavage Cleavage parallel to the lateral planes. Webster 3rd lateral development Any system of development in coal seams or thick orebodies in which headings are driven horizontally across the coal or ore and connected to main haulage drifts, entries, or shafts. There are many variations and modifications depending on the thickness, shape, and inclination of the deposit. See also: horizon mining lateral deviation The horizontal distance by which a borehole misses its intended target. Long lateral draw The angle of draw over a strike face or over workings in a flat seam. Briggs 1751

lateral secretion A theory of ore genesis formulated in the 18th century and passing in and out of use since. It postulates the formation of ore deposits by the leaching of adjacent wall rock. In current usage, convectively driven fluids associated with cooling plutons are thought to have abstracted metals from adjacent host rocks and transported them to new sites of deposition, as in the formation of certain porphyry base-metal deposits. See also: lithogene; segregated vein. AGI lateral support Means whereby walls are braced either vertically or horizontally by columns, pilasters, or crosswalls, or by floor or roof constructions, respectively. ACSG, 1 later arrival A signal that is recorded on a seismogram later than the first arrival of energy. Schieferdecker laterite Red residual soil developed in humid, tropical, and subtropical regions of good drainage. It is leached of silica and contains concentrations particularly of iron oxides and hydroxides and aluminum hydroxides. It may be an ore of iron, aluminum, manganese, or nickel. Adj. lateritic. Syn: latosol laterlog The electrical resistivity of coal appears to decrease with ash content. The laterlog measures what is virtually the true resistivity of the coal and may ultimately provide information on seam quality. The laterlog uses a sheet of current that is focused on each formation in succession and so measures the resistivity of that formation only. The mud column or a salty mud has no effect on the measured resistivity. The laterlog may be measured by a seven- or three-electrode arrangement but the former is preferred. Sinclair, 3 latex cement A specialized cementing material consisting of a portland-type cement, latex, a surfaceactive agent, and water, having a setting time equivalent to a neat portland-cement slurry. Latex cement shrinks less and is tougher, stronger, less permeable, and more durable than portland cement. Long Latex spray 1752

Trade name for a synthetic rubber fluid, which, when sprayed onto underground stoppings, forms a tough nonflammable coating thus preventing air feeding fires or heatings, or air leakages through doors, surface air locks, and air crossings. Also called Latex sealant. Nelson lath a. A board or plank sharpened at one end, like sheet piling, used in roofing levels or in protecting the sides of a shaft through a stratum of unstable earth. See: spill b. A long, thin mineral crystal. AGI lath frame A weak lath frame, surrounding a main crib, the space between being for the insertion of piles. Fay lathlike Refers to crystals with three distinctly different dimensions. CF: acicular; tabular; rodlike; equant. laths a. Corn. The boards or lagging put behind a frame of timber. Fay b. Corn. Pieces of timber about 4 ft 6 in by 6 in by 2 in (1.4 m by 15 cm by 5 cm) with end sharpened or beveled to give the lath an upward trend when being driven into the roof gravels. A number of laths driven into the roof form a protective shield for the miners working in the face. Also called lagging. Eng. Min. J., 1 latite A porphyritic extrusive rock having phenocrysts of plagioclase and potassium feldspar in nearly equal amounts, little or no quartz, and a finely crystalline to glassy groundmass, which may contain obscure potassium feldspar; the extrusive equivalent of monzonite. Latite grades into trachyte with an increase in the alkali feldspar content, and into andesite or basalt, depending on the presence of sodic or calcic plagioclase, as the alkali feldspar content decreases. It is usually considered synonymous with trachyandesite and trachybasalt, depending on the color. The name, given by Ransome in 1898, is derived from Latium, Italy. AGI latitude correction a. The north-south correction made to observed magnetic-field intensity in order to remove the Earth's normal field (leaving, as the remainder, the anomalous field). AGI b. A correction of gravity data with latitude, because of variations in centrifugal force 1753

owing to the Earth's rotation and because of differences in the radius owing to polar flattening. The correction for latitude phi amounts to 1.308 sin 2 phi mgal/mi = 0.813 sin 2 phi mgal/km. AGI latosol See: laterite latrobite A pink anorthite from Amitok Island, LB, Canada. Standard, 2 latten Metal in thin sheets, esp. (and originally) brass, which in this form is also called latten brass. Standard, 2 lattice An array of points in space such that each point is in an identical point environment. Thus, any straight line drawn between any two points in a lattice and continued will pass at equal intervals through a succession of similar points. Fourteen possible lattices exist. Syn: Bravais lattice; space lattice. CF: net; row. lattice constant See: lattice parameter lattice energy Energy required to separate the ions of an ionic crystal to an infinite distance from each other. Pryor, 3 lattice girder An open girder, beam, or column in timber, steel, or aluminum alloy, built up from structural members joined and braced together by intersecting diagonal bars. See also: space lattice lattice parameter Lattice parameters are the unit lengths along each crystallographic axis and their interaxial angles. See also: axial element lattice texture 1754

a. In mineral deposits, a texture produced by exsolution in which elongate crystals are arranged along structural planes. AGI b. A texture that is typical of the mineral serpentine in a rock where it replaces an amphibole. CF: knitted texture lattice water a. Water that is an integral part of the clay structure. This structural water (OH lattice water) is not to be confused with interlayer water. The lattice water can be removed by heating in the range of about 450 to 600 degrees C. ACSG, 2 b. Molecular water at specific lattice sites. Van Vlack laubanite See: natrolite. laubannite Alternate spelling of laubanite. Laue diagram See: Laue photograph laueite A triclinic mineral, MnFe2 (PO4 )2 (OH)2 .8H2 O ; dimorphous with stewartite. Laue photograph A collection of X-ray diffraction spots made by a crystal using a Laue camera and white radiation. Syn: Laue diagram launder a. A flume, trough, channel, or chute by which water or powdered ore is conveyed in a mining operation. AGI b. An inclined channel, lined with refractory material, for the conveyance of molten steel from the furnace taphole to a ladle. Also spelled lander. Dodd launder man In ore dressing, smelting, and refining, a laborer who maintains and repairs the launders (long boxes), used to convey water and mill pulp between the various units of oretreating equipment in a mill. DOT 1755

launder screen A screen used for the sizing and dewatering of small sizes of anthracite. Mitchell launder separation process In this process, a stream of fluid carries the material to be separated down a channel provided with draws for separating a heavy-gravity product and means for overflowing a lighter one. If properly constructed and operated, a comparatively solid bed of material will form on the bottom of the launder. Above this bed, a layer of particles will move along by the stream at a comparatively slow speed. Above this, successive layers will move with greater and greater velocity. Mitchell launder washer A type of coal washer in which the coal is separated from the refuse by stratification due to hindered settling while being carried in aqueous suspension through a trough. Modern launder washers have various mechanisms for continuously removing refuse from the bottom of the trough. Early launder washes were intermittent in operation. laundry box The box at the surface receiving the water pumped up from below. Fay Laurasia Hypothetical continent in the Northern Hemisphere that broke up about the end of the Carboniferous Period to form the present northern continents. laurdalite An alkalic syenite containing more than 10% modal feldspathoids and characterized by porphyritic texture. Also spelled lardalite. The name, given by Broegger in 1890, is for Laurdal, Norway. AGI Laurentian granite A name that was originally applied to Precambrian granites of the Laurentian Highlands, eastern Canada, and later to the oldest granites near the U.S.-Canadian border northwest of Lake Superior. laurionite An orthorhombic mineral, PbCl(OH) ; dimorphous with paralaurionite; in ancient leadore slags. 1756

laurite An isometric mineral, RuS2 ; pyrite group; occurs with other platinum-group minerals in ultramafic and placer deposits. lauroleic acid Unsaturated fatty acid, C12 H22 O2 . Pryor, 3 laurvikite See: larvikite lausenite A monoclinic mineral, Fe2 (SO4 )3 .6H2 O . lautarite A monoclinic mineral, Ca(IO3 )2 . Lauth mill Mill with three rolls, the middle roll being much smaller than the other two. Only the two larger rolls are driven, work being performed between the bottom and middle and middle and top rolls alternately; the roll setting is adjusted between passes. Osborne lautite An orthorhombic mineral, CuAsS . lava breccia See: volcanic breccia lava dome A dome-shaped mountain of solidified lava in the form of many individual flows, formed by the extrusion of highly fluid lava, e.g., Mauna Loa, HI. See also: shield volcano lavatory A place where gold is obtained by washing. Standard, 2 1757

lavendine See: amethystine quartz lavenite A monoclinic mineral, (Na,Ca)2 (Mn,Fe)(Zr,Ti)Si2 O7 (O,OH,F)2 . Also spelled laavenite. lavialite A metamorphosed basaltic rock with relict phenocrysts of labradorite in an amphibolitic groundmass. The term was originated by Sederholm in 1899, who named it after Lavia, Finland. AGI lavrovite A chromian variety of diopside. Also spelled lavroffite; lawrowite. lawn A fine-mesh gauze used as a sieve for clay. Crispin law of cosines In trigonometry, a law stating that in any triangle the square of one side equals the sum of the squares of the two other sides minus twice the product of these two other sides multiplied by the cosine of the included angle. Jones, 2 law of equal volumes In ore genesis, the statement that during the formation of ore by replacement there is no change in rock volume or form. Syn: Lindgren's volume law law of extralateral rights See: apex law law of gravitation The law, discovered by Sir Isaac Newton, that every particle of matter attracts every other particle of matter, and the force between them is proportional to the product of their masses divided by the square of their distance apart. See also: gravitation; gravity. Standard, 2 law of mass action 1758

The rate of a chemical reaction is directly proportional to the molecular concentrations of the reacting substances. law of motion A statement in dynamics that a body at rest remains at rest and a body in motion remains in uniform motion in a straight line unless acted upon by an external force. The acceleration of a body is directly proportional to the applied force and is in the direction of the straight line in which the force acts. For every force there is an equal and opposite force or reaction. Webster 3rd law of refraction a. When a wave crosses a boundary, the wave normal changes direction in such a manner that the sine of the angle of incidence between wave normal and boundary normal divided by the velocity in the first medium equals the angle of refraction divided by the velocity in the second medium. AGI b. Light, upon crossing a boundary between two transparent substances of different optical densities, changes direction according to n2 /n1 =sin i, where n1 is the refractive index (RI) for the incident light ray making an angle i, and n2 is the RI for the refracted light ray making an angle r with the boundary (n1 < n2 ). Light rays refracted according to this law are called "ordinary" rays. CF: critical angle; extraordinary ray; ordinary ray; total reflection. Syn: Snell's law law of sines In trigonometry, a law stating that in any triangle (either right or oblique) the sides are proportional to the sines of their opposite angles. Jones, 2 law of superposition A general law upon which all geologic chronology is based: In any sequence of sedimentary strata (or of extrusive igneous rocks) that have not been overturned, the youngest stratum is at the top and the oldest at the base; i.e., each bed is younger than the bed beneath, but older than the bed above it. The law was first clearly stated by Steno (1669). AGI lawsonite An orthorhombic mineral, 4[CaAl2 Si2 O7 (OH)2 .H2 O] ; dimorphous with partheite; pale blue; Mohs hardness, 8; in high-pressure, low-temperature schists. laxmannite See: vauquelinite 1759

lay a. The direction, or length, of twist of the wires and strands in a rope. Zern b. The length of lay of wire rope is the distance parallel to the axis of the rope in which a strand makes one complete turn about the axis of the rope. The length of lay of the strand, similarly, is the distance in which a wire makes one complete turn about the axis of the strand. c. To close or withdraw from work; said of collieries. Standard, 2 d. The pitch or angle of the helix of the wires or strands of a rope, usually expressed as the ratio of the diameter of the strand or rope to the length required for one complete twist. Hunt e. Prov. Eng. A standard of fineness for metals; possible from the Spanish ley. Hess lay-by a. Siding in otherwise single-track underground tramming road. Pryor, 3 b. A term used for an underground siding at or near a shaft for storing empty mine cars. c. See: bank layer a. A bed or stratum of rock. b. One of a series of concentric zones or belts of the Earth, delineated by seismic discontinuities. A classification of the interior of the Earth that designates layers A to G from the surface inward. AGI layer depth Thickness of the mixed surface layer of water. Hy layered N. of Eng. Choked up with sediment or mud. layering See: bedding layering number A dimensionless number, the value of which, taken in conjunction with inclination, roughness, and whether the ventilation is ascensional or descensional, determines the mixing and movement of combustible gases roof layers. BS, 8 layering of combustible gases The formation of a layer of combustible gases at the roof of a mine working and above the ventilating air current. BS, 8 1760

layer-loading Procedure for loading coal in railroad cars in horizontal layers. Layer-loading is a simple and inexpensive method for smoothing out the irregularities in coal and consists in shuttling two to six railroad cars, hooked together, past the loading boom two or more at a time. This results in a more uniform product. Mitchell laying out See: setting out lay of rope See: winding rope lay of the land See: topography layout a. The design or pattern of the main roadways and workings. The proper layout of mine workings is the responsibility of the manager aided by the planning department. Nelson b. The map of a mine or part of a mine, usually including future workings arrangement. BCI c. Diagram showing disposition of machines in a mill's flow line. Pryor, 3 lay rope Ordinary lay rope has the wires twisted in a direction opposite to the twist of the strands in the rope. The pitch of wire is from 2-1/2 to 3 times the diameter of the rope, and the pitch of the strands is from 6-1/2 to 9 times the diameter of the rope, the wires being exposed only in short lengths at intervals. Lewis lazarevicite See: arsenosulvanite lazuli See: lapis lazuli lazulite a. A monoclinic mineral, 2[MgAl2 (PO4 )2 (OH)2 ] ; forms a series with scorzalite; azure blue; in granite pegmatites and quartz veins; may be a blue gemstone. Syn: azure spar; 1761

blue spar; false lapis; berkeleyite; klaprothine. (Not lazurite.) b. The mineral group barbosalite, hentschelite, lazulite, and scorzalite. lazulitic Of, pertaining to, or having the characteristics of lazulite. Standard, 2 lazurite a. An isometric mineral, (Na,Ca)8 (Al,Si)12 (O,S)24 [(SO4 ),Cl2 ,(OH)2 ] of the sodalite group; deep blue to greenish blue; a contact metamorphic product in limestone; may be a blue gemstone (lapis lazuli). Also spelled lasurite. (Not lazulite.) See also: Chilean lapis b. See: azure; azurite. lazy balk a. Eng. A timber placed at the top of a hopper, against which the top of the car strikes in dumping, to prevent the car from falling into the hopper. Fay b. Eng. The balk or girder held in position by a banger. Also called lazy girder. SMRB lazy bench The bench to one side of the drill tripod or derrick floor where visitors and workers can sit while observing the drilling operation. Long lazy girder See: lazy balk lazy tong conveyor See: accordion roller conveyor L.D. steel process Process in which oxygen is blown downwards at high velocity through a watercooled lance onto the surface of the hot metal contained in a basic lined vessel. To offset the intense heat produced, coolant materials are added with the original charge. These may be iron ore, sinter, or roll scale, but usually steel scrap is the main material used. As much as 26% of scrap may be used. After about 20 min, the charge is converted into liquid steel. During the process, tests and analyses are made and materials may be added to bring the metal to the required grade and temperature. See also: open-hearth process; O.L.P. steel process. Nelson leachate 1762

A solution obtained by leaching; e.g., water that has percolated through soil containing soluble substances and that contains certain amounts of these substances in solution. Syn: lixivium leach dump Low-grade ores that are dumped loosely in piles on soil surfaces so that fluids may be sprinkled on the piles to leach recoverable metals. SME, 1 leached zone The part of a lode above the water table, from which some ore has been dissolved by down-filtering meteoric or spring water. leacher In ore dressing, smelting, and refining, one who dissolves valuable metal out of ore or slime, using chemical solution. DOT leach hole See: sinkhole leaching a. The separation, selective removal, or dissolving-out of soluble constituents from a rock or orebody by the natural action of percolating water. AGI b. Dissolution from ore or concentrates after suitable comminution to expose the valuable minerals, by aqueous and chemical attack. If heat and pressure are used to intensify or speed this, the work is called pressure leaching. See also: chemical extraction; hydrometallurgy. Pryor, 3 c. The removal in solution of nutritive or harmful constituents (such as mineral salts and organic matter) from an upper to a lower soil horizon by the action of percolating water, either naturally (by rainwater) or artificially (by irrigation). AGI d. The extraction of soluble metals or salts from an ore by means of slowly percolating solutions; e.g., the separation of gold by treatment with a cyanide solution. Syn: lixiviation leaching rate test A test designed to assess the value of antifouling compositions by measuring the rate of loss of toxic ingredients from a painted surface during immersion in seawater. Osborne leach material Material sufficiently mineralized to be economically recoverable by selectively dissolving the wanted mineral in a suitable solvent. See also: leaching 1763

leach pile Mineralized materials stacked so as to permit wanted minerals to be effectively and selectively dissolved by application of a suitable solute. leach precipitation float A mixed method of chemical reaction plus flotation developed for such copper ores as chrysocolla and the oxidized minerals. The value is dissolved by leaching with acid, and the copper is reprecipitated on finely divided particles of iron, which are then recovered by flotation, yielding an impure concentrate in which metallic copper predominates. Abbrev., L.P.F. Pryor, 3 lead a. A bluish-white metal of bright luster, very soft, highly malleable, ductile, and a poor conductor of electricity; very resistant to corrosion; a cumulative poison. Symbol, Pb. Rarely occurs in native form; chiefly obtained from galena (PbS). Lead is used in storage batteries, cable covering, plumbing, ammunition, antiknock gasoline, radiation shielding, and to absorb vibration. Other lead compounds are used in paints, fine glass, and lenses. Environmental concern with lead poisoning has resulted in a U.S. national program to reduce the concentration of lead in gasoline. Handbook of Chemistry and Physics, 3 b. An open watercourse, usually artificial, leading to or from a mill, mine, or reservoir. Syn: leat c. See: ledge; lode. CF: blind lead d. A placer deposit. CF: blue lead; deep lead. Pron. leed. e. A defined gutter of auriferous wash. Pron. leed. Gordon f. A track haulage term for the distance from the point of a frog to the point of the switch. Pron. leed. Kentucky g. A term sometimes used for the distance between the sheave and the winding drum centers. The greater the lead, other things being equal, the smaller the fleeting angle. Too great a lead results in vibration and whipping of the rope between sheave and drum. Idler or sag rollers are frequently installed where long leads are necessary. Pron. leed. Nelson h. The distance a bit is held suspended off bottom in a borehole before rotation and downward movement of the drill string is started. Pron. leed. Long i. Commonly used synonym for ledge or lode. Many mining location notices describe the locator's claim as extending a certain number of feet along and so many feet on each side of the lode, lead, vein, or ledge. Thus Lead, S. Dak., was so named because of the Homestake lead. Blind lead: A lead or vein that does not outcrop or show at the surface. Used esp. at Virginia City, NV. CF: lode j. Properly, placer gravels. Blue lead: A Tertiary river channel at Placerville, CA. So called because of the bluish-gray color of the gravels. Deep lead: Goldbearing gravels deeply covered with debris or lava applied particularly to those of Victoria, Australia. Pron. leed. Fay k. The longitudinal distance traveled in one revolution by a spiral thread or screw. Pron. leed. Long lead-acid accumulator

1764

A secondary cell battery with an electromotive force of about 2 V. It is suitable for work where a steady voltage is required, and extensively used for motor car lighting, miners' safety lamps, shuttle cars, and battery locomotives. Morris leadage The distance coal has to be hauled from the mine to its place of shipment. Standard, 2 lead azide A nitrite of lead, Pb(N3 )2 , used as an initiating explosive in blasting caps. lead bath A furnace in which gold or silver ores are smelted with lead. Standard, 2 lead button In the separation of the noble metals from their impurities, lead is fused with the ore. The bullion so formed drops to the bottom of the crucible in the lead button from which the precious metal is extracted by cupellation. Syn: crucible assay lead carbonate See: cerussite; white lead ore. lead edge The surfaces or inset cutting points on a bit that face in the same direction as the rotation of the bit. Long leader a. A narrow vein branching upwards at an angle from a much larger vein. See also: dropper b. A thin layer of coal, coaly shale, or ironstone that serves as a guide or datum toward workable beds in a mine. leaders Guides in a pile frame to take the drop hammer of a pile driver. Hammond lead feldspar Synthetic PbAl2 Si2 O8 . 1765

lead fume The fume escaping from lead furnaces and containing both volatilized and mechanically suspended metalliferous compounds. Fay lead glance See: galena leadhillite A monoclinic mineral, 8[Pb4 (SO4 )(CO3 )2 (OH)2 ] ; trimorphous with macphersonite and susannite; soft; may fluoresce yellow; in oxidized zones of lead-ore deposits. leading heading The one of a pair of parallel headings that is kept a short distance in advance of the other. This may be adopted to drain the water and thus secure one dry heading. The term is also applied to a heading that is driven in the solid coal in advance of the general line of face. Nelson leading place Scot. A working place in advance of the others, such as a heading or a level. Fay leadings Derb. Small sparry veins in the rock. Syn: leader leading stone See: lodestone leading winning Aust. A heading in advance of the ordinary bords. A leading bank. Fay leading wire An insulated wire strung separately or as a twisted pair, used for connecting the two free ends of the circuit of the blasting caps to the blasting unit. See also: leads lead lap

1766

a. A gem cutter's lap, of lead, copper, or iron; also, the entire machine. Standard, 2 b. In mechanics, a lap of lead charged with emery and oil. Fay lead metacolumbate Pb(CbO3 )2 ; a ferroelectric material with a Curie temperature of 570 degrees C. The material can be polarized to obtain piezoelectric properties. Uses include hightemperature transducer applications, sensing devices, and accelerometers. Syn: lead metaniobate lead metaniobate See: lead metacolumbate lead metasilicate See: alamosite lead motorman In ore dressing, smelting, and refining, a person who operates a small electric locomotive (motor) to haul pots of molten lead bullion from a blast furnace to refining kettles for the separation of copper, antimony, silver, and other metals contained in the lead bullion. DOT lead niobate Pb(NbO3 )2 ; a ferroelectric compound having properties that make it useful in hightemperature transducers and in sensing devices. The Curie temperature is 570 degrees C. Dodd lead ocher See: massicot; litharge. lead of a switch The distance measured on the main line from the point of switch to the point of frog. Also called frog distance. Kiser lead rail The lead rail of an ordinary mine switch is the turnout rail lying between the rails of the main track. Kiser 1767

leads The wires, forming part of an electric detonator, to which the shot-firing cable is attached. BS, 12 lead selenide See: clausthalite lead silicate See: alamosite lead spar See: cerussite; anglesite. lead sulfide See: galena; glance. lead tantalate PbTa2 O6 ; a compound believed to have ferroelectric properties and of possible interest as a special electroceramic. The Curie temperature is 260 degrees C. Dodd lead tree A crystalline deposit of metallic lead on zinc that has been placed in a solution of acetate of lead. Standard, 2 lead-uranium ratio The ratio of lead-206 to uranium-238 and/or lead-207 to uranium-235, formed by the radioactive decay of uranium within a mineral. The ratios are frequently used as part of the uranium-thorium-lead age method. AGI lead vitriol See: anglesite lead-well man In ore dressing, smelting, and refining, a person who maintains flow of molten lead from the blast furnace to the lead pot for removal to refinery. DOT 1768

lead wires a. In blasting, the heavy wires that connect the firing current source or switch with the connecting or cap wires. Nichols, 1 b. Two insulated copper wires leading from the battery or igniting apparatus to the primer cartridge in an explosive charge. Also called connecting wires. Stauffer lead works A place where lead is extracted from the ore. Fay lead zirconate PbZrO3 ; a ferroelectric material. It is also used in lead titanate-zirconate (P.Z.T) piezoelectric ceramics. Dodd leaf A very thin sheet or plate of metal, as gold. Standard, 2 leaf clay See: book clay league a. Any of various linear units of distance, ranging from about 2.42 to 4.6 statute miles (3.89 to 7.4 km); esp. land league (an English land unit equal to 3 statute miles or 4.83 km) and marine league (a marine unit equal to 3 nmi or 5.56 km). AGI b. Any of various units of land area equal to a square league; esp. an old Spanish unit for the area of a tract 5,000 varas square, equal to 4,428.4 acres (1,792.1 ha) in early Texas land descriptions or equal to 4,439 acres (1,796 ha) in old California surveys. AGI leak Low-grade mineralized rock into which an orebody degenerates. Hess leakage An unintentional diversion of ventilation air from its designed path. BS, 8 leakage coefficient A numerical expression of a duct's liability to leak. The National Coal Board of Great Britain defines this as the volume of air in cubic feet per minute that would leak from 1769

100 ft (30 m) of a ventilation duct under a uniform pressure of 1 in (2.54 cm) of water gage. Roberts, 1 leakage halo A dispersion pattern formed by the movement of ore-forming fluids in the rock overlying a mineral deposit. leakage intake An additional intake that is a component part of a system of controlled leakage. BS, 8 leakage intake system A ventilation circuit with two adjacent intake roadways leading to the coalface. The method has been criticized because the air flow may become so sluggish as to cause combustible gases layers. See also: two intakes Nelson leakage resistance The resistance between the blasting circuit, including lead wires, and the ground. Atlas leak vibroscope An instrument that detects leaks in water, oil, gas, steam, and air lines by amplifying the sound produced by the escaping fluid. Osborne lean a. Of ore, low-grade; submarginal; unpay; of doubtful exploitable value. Pryor, 3 b. A rock in which the minerals sought occur in much less than exploitable amounts. Long c. See: hang d. See: low-grade lean clay A clay of low to medium plasticity owing to a relatively high content of silt or sand. CF: fat clay lean ore A low-grade ore. See also: lean; natural ore. Nelson leap Eng. A dislocation of strata by faulting. 1770

leapfrog system A system employed with self-advancing supports on a longwall face in which alternate supports are advanced on each web of coal removed. To do this, alternate units have to be moved a distance equal to twice the web thickness--half before snaking and half after snaking. Nelson lear See: lehr learies Eng. Empty places; old workings. Fay leasable minerals A legal term that for Federally owned lands, or Federally retained mineral interest in lands in the United States, defines a mineral or mineral commodity that is acquired through the Mineral Lands Leasing Act of 1920, as amended; the Geothermal Steam Act of 1970, as amended; or the Acquired Lands Act of 1947, as amended. These Acts are found in Title 30 of the United States Code - Mineral Lands and Mining. The leasable minerals include oil, gas, sodium, potash, phosphate, coal, and all minerals within Acquired Lands. Acquisition is by application for a Government lease and permits to mine or explore after lease issuance. SME, 1 lease a. A contract between a landowner and another, granting the latter the right to search for and produce oil or mineral substances upon payment of an agreed rental, bonus, and/or royalty. AGI b. The instrument by which such grant is made. c. A piece of land leased for mining purposes. See also: claim; concession system; royalty. leaser A Western colloquiallism meaning lessee. Leasing Act Minerals Deposits of coal, phosphate, oil, oil shale, gas, sodium, potassium and sulfur that can be leased from the U.S. Government under the Mineral Leasing Act for acquired lands. SME, 1 leat 1771

a. A mill stream used by small mines for power generation. Nelson b. A ditch that leads water to mineral workings. Pryor, 3 leatherstone See: mountain leather leaving Corn. The mineral left after the good ore has been removed; tailings. lechatelierite Naturally fused gray siliceous glass; actually a minor rock type varying in composition according to the original sand type, typically 90% to 99.5% silica. CF: fulgurite; impactite. Also spelled lechatelierite. lechosos opal A variety of precious opal exhibiting a deep green play of color; esp. a Mexican opal exhibiting emerald-green play of color and flashes of carmine, dark violet, dark blue, and purple. lecontite An orthorhombic mineral, (NH4 ,K)Na(SO4 ).2H2 O ; occurs in bat guano. led N. of Eng. A spare tub, or one that is being loaded while another is being emptied. Fay ledge a. A narrow shelf or projection of rock, much longer than wide, formed on a rock wall or cliff face. AGI b. A rocky outcrop; solid rock. AGI c. An underwater ridge of rocks, esp. near the shore; also, a nearshore reef. AGI d. A quarry exposure or natural outcrop of a mineral deposit. AGI e. A bed or several beds in a quarry or natural outcrop, particularly those projecting in a steplike manner. AGI f. The surface of such a projecting bed. AGI g. In mining, a projecting outcrop or vein, commonly of quartz, that is supposed to be mineralized; also, any narrow zone of mineralized rock. AGI h. A mass of rock that constitutes a valuable mineral deposit. Webster 3rd i. A colloquial syn. of bedrock, used in northern Michigan. Long j. The only true ledges are deposits of oil-shale, slate, or the like. A ledge is a horizontal layer, therefore a vein or lode is not a ledge. von Bernewitz k. A rocky formation continuous with and fringing the shore. Syn: lead Hunt 1772

ledge rock True bedrock. CF: false bottom Leebar separator A dense medium washer consisting of a static bath. The floats, or clean coal, are removed by means of paddles or chains suspended from bars connected to rotating spokes. The sinks, or shale, are extracted by a scraper device. The bath can be fed directly from the raw coal screens. The separator has been developed for the treatment of large coal. See also: Nelson Davis separator Lee configuration a. An electrical resistivity measuring method using two current electrodes and three equispaced potential electrodes. AGI b. A configuration employing electrodes, the outer two of which are the current and the inner three of which are the potential electrodes. Syn: partitioning method leelite A reddish variety of potassium feldspar. Lee-Norse miner A continuous miner, developed in the United States, for driving headings in medium or thick coal seams. It weighs about 26 st (23.6 t), and makes a cut 8-1/2 ft (2.6 m) wide, gathers the cut coal and loads it into cars or conveyor at a rate up to about 4 st/min (3.6 t/min). It can work in seam heights from 3 ft 8 in (1.1 m) up to about 10 ft (3 m). It consists, mainly, of a boom carrying the cutting head; the gathering head, and at the rear the jib support frame on which the jib can be slewed. The machine is operated by hydraulic motors. Nelson leer See: lehr leering In glassmaking, the process of treating in the annealing oven or leer. Standard, 1 Leet seismograph A portable three-component seismograph designed primarily for registration of vibrations from blasts, traffic, machinery, and general industrial sources. Leet, 2 1773

lefkasbestos A bleached-white variety of asbestiform chrysotile from Mt. Troodos, Cyprus. left bank The bank of a stream that is to the left of an observer facing downstream. left lang lay Wire or fiber rope or cable in which the wires or fibers in a strand and the strands themselves are twisted to the left. Long left-lateral fault A fault on which the displacement is such that the side opposite the observer appears displaced to the left. CF: right-lateral fault Syn: sinistral fault left long lay See: left lang lay left regular lay Wire or fiber rope or cable in which the individual wires or fibers in the strands are twisted to the right and the strands to the left. Syn: regular-lay left lay left twist See: right lay leg a. In mine timbering, a prop or upright member of a set or frame. Also called upright; post; arm. Pryor, 3; Nelson b. One of the main upright members of a drill derrick or tripod. Long c. A term sometimes applied to a centrifugal discharge bucket elevator. Usually a double leg bucket elevator. d. See: draft e. A side post in tunnel timbering. Nichols, 1 legend A brief explanatory list of the symbols, cartographic units, patterns (shading and color hues), and other cartographic conventions appearing on a map, chart, or diagram. On a geologic map, it shows the sequence of rock units, the oldest at the bottom and the 1774

youngest at the top. The legend formerly included a textual inscription of, and the title on, the map or chart. Syn: key leg piece The upright timber that supports the cap piece in a mine. CF: legs Fay legrandite A monoclinic mineral, 8[Zn2 (AsO4 )(OH).H2 O] . legs a. The wires attached to and forming a part of an electrical blasting cap. Fay b. The uprights of a set of mine timbers. See also: dap; leg piece. Fay legua Sp. Land league used in the original surveys of the Philippines, California, and Texas. It is equal to 2.63 miles or 4.24 km. See also: league leg wire One of the two wires attached to and forming a part of an electric blasting cap or squib. Lehigh jig A plunger-type jig with the following distinguishing characteristics: (1) the plunger contains check valves that open on the upstroke to reduce suction; (2) the makeup water is introduced with the feed; (3) the screen plate is at two levels, which have different perforations, to keep the water distribution uniform; (4) the bottom of the discharge end of the jig is hinged. This jig has been used extensively in washing anthracite. Mitchell lehiite A mixture of crandallite with other minerals. Lehmann process A process for treating coal by disintegration and separation of the petrographic constituents (fusain, durain, and vitrain). It consists of subjecting the coal to resilient disintegrating or shattering action for a sufficient length of time to break the constituents into granules of various sizes by reason of their respective resistances to shattering impacts and separating the granules into different sizes by screening or equivalent means. Mitchell 1775

lehr An enclosed oven or furnace used for annealing, or other form of heat treatment; particularly used in glass manufacture. It is a kind of tunnel down which glass, hot from the forming process, is sent to cool slowly, so that strain is removed, and cooling takes place without additional strain being introduced. Lehrs may be of the open type (in which the flame comes in contact with ware), or of the muffle type. Syn: leer; lear. CTD lehr man Person who regulates temperature of a reheating oven (lehr) used to fire-glaze glass articles. Arranges glass articles according to size and shape on lehr conveyor so that maximum quantity will be carried in oven on a long paddle. Also called leer man; lehr operator, glass; lehr tender. DOT lehrnerite See: ludlamite leightonite A triclinic mineral, K2 Ca2 Cu(SO4 )4 .2H2 O ; pseudo-orthorhombic; blue; at Chuquicamata, Chile. Leitz tyndallometer Measures the intensity of the light scattered at an angle from the incident beam by a dust cloud, and correlates well with the concentration determined by the thermal precipitator or the surface area calculated from such a count. However, it needs to be calibrated for each type of dust cloud, owing to difference in mineralogical content, against the thermal precipitator. Sinclair, 1 Lemberg's solution Logwood digested in an aqueous solution of aluminum chloride; used to distinguish calcite and dolomite. Calcite and aragonite are stained violet after treatment for about 10 min, but dolomite remains unchanged. lenad A contracted form of the names leucite and nephelite; suggested as an alternative group name for the feldspathoid minerals. CF: feldspathoid lengenbachite 1776

A triclinic mineral, Pb6 (Ag,Cu)2 As4 S13 . lengthening rod A screwed extension rod for prolonging a well-boring auger or bit. Standard, 2 length fast See: negative elongation length of lay The distance measured along a straight line parallel to the rope in which the strand forms one complete spiral around the rope or the wires around the strand. See also: lay length of shot a. The depth of the hole in which the powder is placed, or the size of the block of coal to be loosened by a single blast measured parallel with the hole. b. In open pit mining, the distance from the first drill hole to the last drill hole along the bank. lengths Eng. In tunnel construction, the successive sections in which a tunnel is executed. Shaft lengths are directly under the working shaft; side lengths are on each side of the shaft length; leading lengths are prolongations of the tunnel from the side lengths; and junction lengths complete the portion of the tunnel extending between two shafts, or between a shaft and an entrance. length slow See: positive elongation lennilite a. A green variety of orthoclase at Lenni Mills, Delaware County, PA. Syn: delawarite b. A variety of vermiculite. lens a. A geologic deposit bounded by converging surfaces (at least one of which is curved), thick in the middle and thinning out toward the edges, resembling a convex lens. A lens may be double-convex or plano-convex. See also: lentil; lenticular. ---v. To disappear laterally in all directions; e.g., a unit is said to lens out within a mapped area. AGI b. In optics, a device that modulates the direction taken by a transient beam of light. Pryor, 3 1777

lense Pyrite, round or oval in plan and lenticular in section, ranging up to 2 to 3 ft (0.6 to 0.9 m) in thickness and several hundred feet in the greatest lateral dimension, that is found in coalbeds. Sometimes called kidney sulfur. Mitchell lens grinding The process of grinding pieces of flat sheet glass (or pressed blanks) to the correct form of the lens. Cast-iron tools of the correct curvature, supplied with a slurry of abrasive and water, are used. CTD lensing The thinning-out of a stratum in one or more directions. lenticle a. A large or small lens-shaped stratum or body of rock; a lentil. AGI b. A lens-shaped rock fragment of any size. AGI lenticular a. Resembling in shape the cross section of a lens, esp. of a double-convex lens. The term may be applied, e.g., to a body of rock, a sedimentary structure, or a mineral habit. AGI b. Pertaining to a stratigraphic lens or lentil. Syn: lentiform AGI lenticular iron ore Impure concretionary hematite. lenticule A small lentil. AGI lentiform See: lenticular lentil a. A minor rock-stratigraphic unit of limited geographic extent, being a subdivision of a formation and similar in rank to a member, and thinning out in all directions; a geographically restricted member that terminates on all sides within a formation. CF: 1778

tongue b. A lens-shaped body of rock, enclosed by strata of different material; a geologic lens. See also: lenticule; lenticle. AGI lentil ore See: liroconite leonardite a. A soft, earthy, medium-brown coallike substance associated with lignitic outcrops in North Dakota. It is a naturally oxidized form of lignite with variations in color and properties depending upon the extent of weathering. Usually, the material occurs at shallow depths, overlying or grading into the harder and more compact lignite. Of little value as a fuel, it has been used in oil-drilling muds, in water treatment, and in certain wood stains. It is frequently referred to as "slack" because of its texture; however, the term leonardite is finding common usage. b. A weathering product of subbituminous coal or lignite, rich in humic and fulvic acids and soluble in alkaline water. It is a byproduct of mining near-surface coal seams, and is used as a soil conditioner, additive to drilling mud, and binder for taconite iron ore (Fowkes & Frost, 1960). Not to be confused with leonhardite or leonhardtite. AGI Leon combustible gases tester A combustible gases detector developed in 1902. A form of Wheatstone bridge is used and changes in electrical resistance due to temperature differences are measured. The combustible gases/air sample flows over one set of wires and the gas burns catalytically while the other wires do not come into contact with the sample. Nelson leonhardite A partially dehydrated variety of laumontite. (Not leonhardtite.) leonhardtite See: starkeyite leonite A monoclinic mineral, K2 Mg(SO4 )2 .4H2 O ; in marine evaporite deposits. Syn: magnesium leonite leopardite

1779

A variety of quartz porphyry containing small phenocrysts of quartz in a microgranitic groundmass of quartz, orthoclase, albite, and mica. The rock has a characteristically spotted or streaked appearance due to staining by hydroxides of iron and manganese. leopard rock a. Can. Pegmatitic rocks associated with the apatite veins of Ontario and Quebec. b. Syenite gneiss consisting of ellipsoidal lumps measuring several inches across and separated by material that is mainly greenish pyroxene. The rock may be slightly schistose. Leopard stone Dolomite full of worm castings set in a gray matrix and containing chert nodules, near the base of the Upper Cambrian, Scotland. Leopoldi furnace A furnace for roasting mercury ores in a batch process, differing from the Bustamente furnace in having a series of brick condensing chambers. Fay leopoldite See: sylvite lepidoblastic Pertaining to a flaky schistosity caused by an abundance of minerals like micas and chlorites with a general parallel arrangement. lepidocrocite An orthorhombic mineral, 4[gamma-FeO(OH)] ; polymorphous with akaganeite, feroxyhyte, and goethite; yellow to orange-red; the weathering product of iron-bearing minerals; forms the pigment brown ocher; such iron oxyhydroxides constitute the rock limonite. lepidolite a. A monoclinic, trigonal, or orthorhombic mineral; 1, 2, or 3[K2 Li4 Al2 (Si8 O20 (OH)4 ] ; mica group; forms a series with muscovite; perfect basal cleavage; pink to purple; in lithium-rich granite pegmatites; a source of lithium. Syn: lithia mica; lithionite. b. A group name for lithium-rich micas. lepidomelane 1780

A black ferrian variety of biotite. lepidomorphite A variety of phengite, a siliceous variety of muscovite. lepolite See: anorthite leptothermal Said of a hydrothermal mineral deposit formed at temperature and depth conditions intermediate between mesothermal and epithermal; also, said of that environment. CF: hypothermal deposit; xenothermal; telethermal. AGI leptynolite A fissile or schistose variety of hornfels containing mica, quartz, and feldspar, with or without accessories, such as andalusite and cordierite. The term was originated by Cordier in 1868. CF: cornubianite AGI Lerchs-Grossmann optimization A mathematical method based on a block model of an orebody used for determining the most profitable optimum shape for an open pit. lernilite See: vermiculite lesleyite a. A mixture of a hydromica and corundum. b. A potassian variety of margarite. Lessing process A heavy-fluid coal-cleaning process in which a calcium chloride solution having a specific gravity of approx. 1.4 is used for the separation, which takes place in a cylindrical tank 6 to 10 ft (1.8 to 3 m) in diameter with a conical bottom, the total height being nearly 30 ft (9.1 m). The cleaned coal rises to the top where it is removed by a chain scraper and delivered to draining towers. Gaudin, 1 lethal dose 1781

A dose of ionizing radiation sufficient to cause death. Median lethal dose (abbreviated MLD or LD50 ) is the dose required to kill half of the individuals in a group similarly exposed within a specified period of time. The median lethal dose for humans is about 400 rads. Lyman let into Eng. The recessing of supports into the floor, side, or roof. SMRB letovicite A triclinic mineral, (NH4 )3 H(SO4 )2 ; a decomposition product of pyrite in coal. letter and tracing cutter In the stonework industry, a person who cuts incised or raised letters and simple designs on monumental stones with pneumatic and hand tools. Also called letter cutter; letterer. DOT letter stone An igneous rock with sheath and core structure giving the appearance of letters on its surface. lettsomite See: cyanotrichite; velvet copper ore. leuchtenbergite A pale iron-poor variety of clinochlore. leucite A tetragonal mineral, 16[KAlSi2 O6 ] ; a pseudocubic feldspathoid; forms white to gray trapezohedra in potassium-rich, silica-poor lavas. Syn: amphigene; grenatite; white garnet; vesuvian. CF: pseudoleucite leucitite A fine-grained or porphyritic extrusive or hypabyssal igneous rock chiefly composed of pyroxene (esp. titanaugite) and leucite, with little or no feldspar and without olivine. AGI leucitohedron 1782

See: trapezohedron leucitophyre A porphyritic extrusive rock composed chiefly of leucite, nepheline, and clinopyroxene. CF: haueynophyre leucochalcite See: olivinite leucocratic Light-colored; applied to igneous rocks that are relatively poor in mafic minerals. The percentage of mafic minerals necessary for a rock to be classified as leucocratic varies among petrologists, but is usually given as less than 30% to 37.5%. CF: melanocratic; mesocratic. Noun, leucocrate. Syn: light-colored leucomanganite See: fairfieldite leucoperthite A loamlike substance, between a resin and wax in character; C50 H84 O3 ; very impure and sandy as found in a brown coal at Gesterwitz, near Weissenfels, Germany. It crystallizes in white needles from ether and boiling absolute alcohol, and melts above 100 degrees C. AGI leucophane A green to pale-yellow sodium calcium silicate containing beryllium. One of the sources of beryllium. See also: leucophanite leucophanite A triclinic mineral, (Na,Ca)2 BeSi2 (O,OH,F)7 ; pseudo-orthorhombic; a source of beryllium. Syn: leucophane leucophoenicite A monoclinic mineral, Mn7 (SiO4 )3 (OH)2 ; humite group; pseudo-orthorhombic; purple-pink to raspberry-red; in veins associated with manganese ore deposits. leucophyllite 1783

A variety of muscovite. Dana, 1 leucophyre A term originally applied to altered diabase in which the feldspar has been altered to saussurite, kaolin, and chlorite. This usage is obsolete, but the term is occasionally used for a light-colored hypabyssal rock, being the antithesis of lamprophyre. Not recommended usage. AGI leucopyrite An oxidized variety of loellingite. See also: loellingite leucosphenite A monoclinic mineral, BaNa4 Ti2 B2 Si10 O30 ; in alkali pegmatites and the Green River Formation of Utah and Wyoming. leucoxene a. Fine-grained, opaque white alteration products of ilmenite, mainly finely crystalline rutile. b. A variety of sphene. levee An embankment beside a river or an arm of the sea, to prevent overflow. Standard, 2 level a. A main underground roadway or passage driven along a level course to afford access to stopes or workings and to provide ventilation and a haulageway for the removal of coal or ore. Levels are commonly spaced at regular depth intervals and are either numbered from the surface or designated by their elevation below the top of the shaft. See also: level interval b. See: mother gate c. An instrument for establishing a horizontal line or plane. Long d. The act or process of adjusting something with reference to a horizontal line. Long e. In pitch mining, such as anthracite, there may be a number of levels driven from the same shaft, each being known by its depth from the surface or by the name of the bed or seam in which it is driven. Jones, 1 f. Applied to seams that run like floors in an office building. Under and above the seam lie the rock strata. Korson g. All openings at each of the different horizons from which the orebody is opened up and mining is started. Higham h. N.S.W. A drive in a mine. New South Wales i. In speleology, a series of related passageways in a cave, occurring at the same relative, vertical position. AGI j. A gutter for the water to run in. Fay level course 1784

a. A direction along the strike of an inclined coal seam; a coal seam contour line. The productive faces in a coal mine, such as stalls and conveyor faces are, in general, advanced on level course or slightly to the rise. Nelson b. Scot. In the direction of the strike of the strata, or at right angles to the dip and rise. See also: strike; true dip. Fay level crosscut A horizontal crosscut. See also: crosscut level drive A drive that opens up a deposit and makes it accessible along its length and forms the basis for the division of the deposit into levels. Stoces leveler A buck scraper, drag, or any other form of device for smoothing land. Seelye, 1 level-free a. War. Old coal or ironstone workings at the outcrop, worked by means of an adit driven into the hillside. b. A mine that discharges water by gravitation. leveling The operation of determining the comparative altitude of different points on the Earth's surface, usually by sighting through a leveling instrument at one point to a level rod at another point. Also, the finding of a horizontal line or the establishing of grades (such as for a railway roadbed) by means of a level. Also spelled levelling. AGI leveling instrument A surveyor's level bearing a telescope. See also: level Standard, 2 leveling practice In leveling, the station is the point at which the staff is held and not the position of the instrument. The operation is one of carrying forward a known level, hence the backsight is a reading taken on the staff at a known elevation and the last sight from each station is called the foresight. All other readings refer to intermediate sights. Leveling sections may be referred to bench marks or to arbitrary levels, but in all cases they must be checked either by closing on the starting point or by starting and finishing on convenient bench marks. Mason leveling rod 1785

A graduated rod used in measuring the vertical distance between a point on the ground and the line of sight of a surveyor's level. Webster 3rd level interval a. The vertical distance between the levels turned off the shaft in metal mines for ore intersection and development. The interval varies but may be about 150 ft (46 m). Nelson b. The horizontal distance between levels turned off main development drifts and varies from 200 to 600 yd (180 to 550 m). Levels are usually designated by numbers, names, or depth from the surface. Nelson level-luffing crane A crane embodying an automatic device that causes the load to move horizontally with any alteration of the operating radius. Hammond levelman Person who operates a surveyor's level. Crispin level of control A measure of mastery over a process of production; in concrete work, it is measured by cube crushing strength and the standard deviation therefrom. See also: statistical uniformity level of saturation See: water table levels See: level level surface See: equipotential surface leverman Person who operates brakes, or levers, at the top of an inclined plane. A brakeman. Fay levigation

1786

a. Separating fine powder from coarser material by forming a suspension of the fine material in a liquid. ASM, 1 b. A means of classifying a material as to particle size by the rate of settling from a suspension. CF: trituration levitation In the mineral process of froth flotation, raising of acrophilic particles to the surface of a pulp, by so activating them that they cling to the air-water interface of a rising or coursing air bubble. Pryor, 3 levyne A trigonal mineral, (Ca,Na2 ,K2 )3 Al6 Si12 O36 .18H2 O ; zeolite group; in cavities in basalts with other zeolites. Also spelled levynite; levyine; levyite. lewis hole A series of two or more holes drilled as closely together as possible, then connected by knocking out the thin partition between them, forming thus one wide hole, having its greatest diameter in a plane with the desired rift. Blasts from such holes are wedgelike in their action, and by means of them larger and better-shaped blocks can be taken out than would otherwise be possible. Fay Leyner-Ingersoll drill See: water leyner lherzolite A peridotite containing both clinopyroxene and orthopyroxene in addition to olivine. liberation Freeing by comminution, or crushing and grinding, of particles of a specific mineral from their interlock with other constituents of the coal or ore. Also called severance. Syn: unlocking liberation of intergrown constituents Crushing of intergrown material to free the constituent materials. BS, 5 liberator cells In electrolytic refining of metals, tanks in which the electrolytic solution is reconstituted. Pryor, 3 1787

Liberty-Gel Gelatinous permissible explosive; used in mining. Bennett libethenite An orthorhombic mineral, Cu2 (PO4 )(OH) ; olive-green; forms small crystals and druses in copper deposits. LICADO process A selective agglomeration process under development, in which the liquid carbon dioxide-water interface is used for the differentiation and separation between coal and mineral matter. The resultant clean coal is a low-sulfur and low-ash content product of relatively low moisture content. licensed material Source material, special nuclear material, or byproduct material received, possessed, used, or transferred under a general or special license issued by the Nuclear Regulatory Commission. Lyman licensed store A place or building licensed by the local authority for the storage of explosives. See also: magazine; registered premises. BS, 12 lid a. A short, flattish piece of wood or steel plate wedged over a post, timber set, or steel arch. A lid is used to tighten the support against the ground and also to increase the area supported. See also: clog; wedge. Nelson b. A cap piece used in timbering. CF: lag lidman In the coke-products industry, a laborer who lifts lids of charging holes of ovens and chips carbon from edges of holes, using bars with hook-and-chisel ends. Syn: charger lie! Scot. In mine haulage, a command to stop. Fay lie

1788

a. Scot. The line, direction, or bearing; as of a vein, lode, or fault. Fay b. Pass-by; shunt; a storage or bypass arrangement in haulage track. Also spelled lye. Mason c. To become quiet or inactive; said of a mine that is idle. Fay liebigite An orthorhombic mineral, Ca2 (UO2 )(CO3 )3 .11H2 O ; olive-green; forms soft, scaly, or granular crystalline aggregates with one cleavage. Syn: uranothallite lien Right to legal claim on goods or property. Pryor, 1 liesegang banding Banding in color and composition of ores caused by diffusion. AGI lievrite See: ilvaite lifeline A slide wire or cable extending from a work platform in a drill tripod or derrick at an oblique angle downward to an anchor on the ground, which the derrick or tripod worker could grasp and use when sliding to safety in an emergency. Long life of mine The time in which, through the employment of the available capital, the ore reserves--or such reasonable extension of the ore reserves as conservative geological analysis may justify--will be extracted. Hoover life of property Theoretically, the mineral or coal reserves divided by the actual or projected average annual production. Nelson lift a. The vertical height traveled by a cage in a shaft. Fay b. The distance between the first level and the surface or between any two levels. Fay c. Any of the various gangways from which coal is raised at a slope colliery. Fay d. A certain thickness of coal worked in one operation. Fay e. To break up, bench, or blast coal from the bottom of the seam upward. Fay f. The plane approx. parallel with the floor of the quarry, along which the 1789

stone is usually split in quarrying. Fay g. The quantity of ore between one haulage level and the next above or below. Nelson h. A step or bench in a multiple layer excavation. Nichols, 1 i. The amount a bit is raised off the bottom of a drill hole by excessive pressure created by pump surges or the forcing of too great a volume of circulation fluid through the bit. Long j. In churn drilling, the vertical movement of the drill tools while drilling. Long k. In pumping, the difference in the elevation between the surface of the liquid being pumped and the elevation at which the pump stands or the elevation at which the liquid is discharged. Long l. A certain vertical thickness of coal seams and measures, having considerable inclination, between or in which the workings are being carried on to the rise, all the coal being raised from one shaft bottom. Fay m. The upheaval of the floor in coal mines. See also: creep Nelson n. The extraction of a coal pillar in lifts or slices. See also: jud Nelson lifter a. In mining, a shothole drilled near the floor when tunneling and fired subsequently to the cut and relief holes. Pryor, 3 b. See: core lifter c. In ore grinding, a projection, rib or wave profile on the horizontal liners (body liners) of a ball, tube, or rod mill, designed to aid the crop load in the mill to rise. In a drum-washer or dense-medium separator, a perforated plate, projecting radially inward from the circumference of a horizontal cylindrical vessel, used to stir, lift, or remove material. Pryor, 3 lifter holes Shotholes drilled along the floor of a tunnel for lifting the rock to floor level. They are fired after the cut holes, or by delay detonators in the round. Nelson lifters See: lifter holes lifter spring See: core lifter lift gate A lock gate that is raised vertically to open. Hammond lift hammer See: tilt hammer lifting 1790

Scot. Drawing hutches or cars out of the working places into the main roads. Fay lifting block An arrangement of pulleys and rope that enables heavy weights to be lifted with least effort. Hammond lifting capacity a. The weight that the hydraulic cylinders in the swivel head of a diamond drill can raise or lift. Long b. See: drill capacity lifting guard Fencing placed around the mouth of a shaft, and lifted out of the way by the ascending cage. Fay lifting magnet An electromagnet that is hung from a crane and used instead of a hook for lifting iron or steel components. Hammond lifting set A series of pumps or sets of pumps by which water is lifted from the mine in successive stages. See: lift lifting wicket S. of Wales. See: lifting guard lift joint A horizontal tension fracture observed in massive rocks, such as granite; thought to originate from the removal of load in quarrying. CF: sheeting lift pump A pump for lifting to its own level, as distinguished from a force pump. A suction pump. Also called bucket pump. See also: suction head Standard, 2; Fay light alloys The general term for alloys of aluminum and magnesium used for structural purposes. Hammond 1791

light blasting Includes loosening up of shallow or small outcrops of rock and breaking boulders. It may constitute the entire job, be done in connection with dirt excavation, or follow heavy blasting that has failed to cut gradelines or slope lines, or has left chunks too large to load. Nichols, 1 light burden See: burden light-colored See: leucocratic lightening A peculiar brightening of molten silver, indicating that maximum purity has been attained. Occurs in cupellation. Standard, 2; Fay light-extinction method See: turbidimeter light figure The visible geometric figure observed when an etched flat surface of quartz is placed over a pinhole-focused light source. Am. Mineral., 2 lighting In metallurgy, annealing. Standard, 2 lightman Person who uses an electric extension light as an aid in detecting blisters and flaws in the inside of green pipe. DOT light mineral a. A rock-forming mineral of a detrital sedimentary rock, having a specific gravity lower than a standard (usually 2.85); e.g., quartz, feldspar, calcite, dolomite, muscovite, feldspathoids. CF: heavy mineral b. A light-colored mineral. AGI lightning explosion 1792

Eng. An explosion of combustible gases caused by electric current, during a thunderstorm, entering a mine and igniting the gas. Fay lightning gap A lightning gap is a break about 6 ft (1.8 m) long made at the mine entrance in blasting circuits, used in firing blasts from the outside, to prevent lightning discharges from following the circuits into the mine. lightning protection A system to enable high electrical discharge from the atmosphere to be conducted safely to earth by one or more conductors. The provision is very important in the case of mine explosive stores and also headgears, tower winders, and chimneys. Nelson lightning tube See: fulgurite light railway A railway built to narrow gage. Hammond light red silver ore See: proustite light ruby ore See: proustite light ruby silver See: proustite light water Ordinary water, H2 O , as distinguished from heavy water, D2 O , D being the symbol for deuterium (heavy hydrogen or hydrogen 2). Lyman lightweight aggregate An aggregate with a relatively low specific gravity; e.g., pumice, volcanic cinders, expanded shale, foamed slag, or expanded perlite or vermiculite. CF: aggregate 1793

lightweight concrete A concrete made with lightweight aggregate. AGI light-yellow heat A division of the color scale, generally given as about 2,400 degrees F (1,316 degrees C). lignin sulfonic acids Chemicals produced during the sulfite treatment of wood pulps. Of interest in flotation process as a deflocculating agent and protective colloid. Pryor, 3 lignite a. A brownish-black coal in which the alteration of vegetal material has proceeded further than in peat but not so far as subbituminous coal. Fay b. Coal of low rank with a high inherent moisture and volatile matter; in this general sense, lignite may be subdivided into black lignite, brown lignite, and brown coal. BS, 4 lignite A The rank of coal, within the lignitic class of Classification D 388, such that, on the moist, mineral-matter-free basis, the gross calorific value of the coal in British thermal units per pound is equal to greater than 6,300 (14.65 MJ/kg but less than 8,300 (19.31 MJ/kg), and the coal is nonagglomerating. ASTM lignite B The rank of coal, within the lignitic class of Classification D 388, such that, on the moist, mineral-matter-free basis, the gross calorific value of the coal in British thermal units per pound is less than 6,300 (14.65 MJ/kg), and the coal is nonagglomerating. ASTM lignitic Containing lignite. Fay lignitic coal See: subbituminous coal ligurite An apple-green variety of titanite. Standard, 2 1794

likasite An orthorhombic mineral, Cu3 (NO3 )(OH)5 .2H2 O ; sky blue; at Likasi, Kutanga, Zaire. likely Said of a rock, lode, or belt of ground that gives indications of containing valuable minerals. Syn: kindly lill Eng. Greenish-gray shale; weathering yellow; Wenlock Limestone, Dudley. Arkell lillianite An orthorhombic mineral, Pb3 Bi2 S6 . Lilly controller A controller used on both steam and electric winding engines that protects against overspeed, overwind, too rapid acceleration, delayed retardation, and against starting in the wrong direction. It also gives warning of overspeed and indicates by a bell signal when retardation should commence. Sinclair, 5 limb a. That area of a fold between adjacent fold hinges. It generally has a greater radius of curvature than the hinge region and may be planar. Syn: flank b. The graduated margin of an arc or circle in an instrument for measuring angles, such as the part of a marine sextant carrying the altitude scale. AGI c. The graduated staff of a leveling rod. See also: tribrach AGI lime a. Calcium oxide, CaO; specif. quicklime and hydraulic lime. The term is used loosely for calcium hydroxide (as in hydrated lime) and incorrectly for calcium carbonate (as in agricultural lime). AGI b. A cubic mineral, CaO. AGI c. A term commonly misused for calcium in such deplorable expressions as carbonate of lime or lime feldspar. AGI d. A limestone. The term is sometimes used by drillers for any rock consisting predominantly of calcium carbonate. AGI lime boil

1795

A reaction in an open-hearth furnace caused by the decomposition of limestone and the escape of the carbon dioxide gas. This reaction begins before the ore boil is completed. See also: ore boil limeburner Person who burns limestone or shells to make lime. Webster 3rd lime feldspar Misnomer for calcium feldspar. See also: anorthite lime mica See: margarite lime mortar A mortar in which lime is used as a binding agent instead of cement. Nelson lime pan a. A playa with a smooth, hard surface of calcium carbonate, commonly tufa. AGI b. A type of hardpan cemented chiefly with calcium carbonate. Also spelled limepan. AGI lime pit a. A limestone quarry. Webster 3rd b. A pit where lime is made. Webster 3rd lime rock A term used in the Southeastern United States (esp. Florida and Georgia) for an unconsolidated or partly consolidated form of limestone, usually containing shells or shell fragments, with a varying percentage of silica. It hardens on exposure and is sometimes used as road metal. Also spelled limerock. AGI lime set An infusible slag, too high in lime, in an iron blast furnace. lime shells Scot. Calcined limestone. lime-silicate rock 1796

See: calc-silicate rock lime slaker Person who mixes lime and water in rotary slaker or open batch tank to make milk of lime (slaked lime). Also called lime mixer; milk-of-lime slaker; slaker. DOT lime-soda sinter process A process for manufacturing alumina, Al2 O3 . The raw material, such as clay or anorthosite, is sintered with limestone and soda ash to form sodium aluminate and calcium silicate. This sinter is then leached with water, caustic soda solution, or sodium aluminate liquor to dissolve the soluble sodium aluminate. The resulting slurry is then filtered, and the liquor is decomposed as in the Bayer process or is treated with carbon dioxide to precipitate hydrated alumina. When operated in conjunction with the Bayer process to recover alumina and soda from red mud, it is called the combination process. limestone a. A sedimentary rock consisting chiefly (more than 50% by weight or by areal percentages under the microscope) of calcium carbonate, primarily in the form of the mineral calcite, and with or without magnesium carbonate; specif. a carbonate sedimentary rock containing more than 95% calcite and less than 5% dolomite. Common minor constituents include silica (chalcedony), feldspar, clays, pyrite, and siderite. Limestones are formed by either organic or inorganic processes, and may be detrital, chemical, oolitic, earthy, crystalline, or recrystallized; many are highly fossiliferous and clearly represent ancient shell banks or coral reefs. Limestones include chalk, calcarenite, coquina, and travertine, and they effervesce freely with any common acid. Abbrev. ls. AGI b. A general term used commercially (in the manufacture of lime) for a class of rocks containing at least 80% of the carbonates of calcium or magnesium and which, when calcined, gives a product that slakes upon the addition of water. AGI limestone dust Dust prepared by grinding limestone; used to dilute the coal dust accumulation in a mine so that the dust does not form explosive mixtures with air. Rice, 2 limewater Natural water with large amounts of dissolved calcium bicarbonate or calcium sulfate. AGI limit charge A charge that gives a complete loosening of the rock without throwing it excessively. 1797

limiting creep stress A somewhat loose term used to denote the maximum stress at which a material will not creep by more than a certain amount within the working life of the part. It is also used in some short-time creep tests; e.g., the Hatfield time yield. Hammond limiting current density The maximum current density that can be used to get a desired electrode reaction without undue interference, such as may come from polarization. ASM, 1 limiting gradient The maximum railway gradient that can be climbed without the help of a second power unit. Syn: ruling gradient limiting mixture The mixture of coal and rock dusts that will not permit the propagation of an explosion. Rice, 2 limit line The line joining the coal face underground and the surface limit of draw; the boundary of a mine. Nelson limit of draw The point on the surface beyond which no movement occurs. Nelson limit of proportionality The point on a stress-strain curve at which the strain ceases to be proportional to the stress. Its position varies with the sensitivity of the extensometer used in measuring the strain. CTD limits of flammability a. Extreme concentration limits of a combustible in an oxidant through which a flame, once initiated, will continue propagating at a specified temperature and pressure. Van Dolah b. Usually expressed as the limiting percentages of methane in air, beyond which the mixture is no longer flammable. The lowest percentage of methane in air that yields a flammable mixture is called the lower limit of flammability, and the highest percentage of methane in air to yield a similar mixture is called the higher limit of flammability. These limiting percentages depend on a number of factors, such as the initial temperature 1798

and pressure; whether the mixture is at rest or moving; the manner in which the mixture is confined, etc. With methane mixtures at ordinary mine pressures and temperatures, the widest limits of flammability are (1) lower limit of flammability about 5.4% of methane in air; (2) higher limit of flammability about 14.8% of methane in air. See also: methane Nelson limit switch a. A device fitted to an electrically driven hoist or winding engine that becomes effective at the end of a wind to prevent the cage overwinding or underwinding. Nelson b. A control to limit some function. Strock, 2 limnic a. Said of coal deposits formed inland in freshwater basins, peat bogs, or swamps, as opposed to paralic coal deposits. CF: paralic b. Said of peat formed beneath a body of standing water. Its organic material is mainly planktonic. AGI limnic coal basin A coal basin formed inland from the seacoasts, as opposed to a paralic coal basin. AGI limnite See: bog iron; bog iron ore. limonite A rock composed of cryptocrystalline and amorphous hydrated iron oxyhydroxides, generally predominantly goethite with or without adsorbed water, but also akaganeite, feroxyhyte, or lepidocrocite; may be yellow, red, brown, or black; hardness variable; an oxidation product of iron (rust) or iron-bearing minerals and may be pseudomorphous after them; as a precipitate, both inorganic and biogenic, in bogs, lakes, springs, or marine deposits; and as a variety of stalactitic, reniform, botryoidal, or mammillary deposits. It colors many yellow clays and soils and is a minor ore of iron. See also: iron ore; brown hematite; brown umber. CF: bog iron ore meadow ore; yellow ocher. limonitic Consisting of or resembling limonite. limurite

1799

A metasomatic rock found at the contact of calcareous rocks with intruded granite and consisting of more than 50% axinite. Other minerals include diopside, actinolite, zoisite, albite, and quartz. See also: calc-silicate hornfels linarite A monoclinic mineral, 2[PbCu(SO4 )(OH)2 ] ; azure blue; in oxidized zones of lead, copper, and silver deposits. lindackerite A monoclinic mineral, H2 Cu5 (AsO4 )4 .8-9H2 O ; green; forms rosettes and reniform masses with one perfect cleavage. Lindblad-Malmquist gravimeter See: Boliden gravimeter lindgrenite A monoclinic mineral, Cu3 (MoO4 )2 (OH)2 ; green; in tabular crystals from Chuquicamata, Chile. Lindgren's volume law See: law of equal volumes lindstroemite An orthorhombic mineral, Pb3 Cu3 Bi7 S15 . Also spelled lindstroemite. line a. The limit of a surface; a length without breadth; an outline; a contour. Fay b. The course in which anything proceeds, or which anyone takes; direction given or assured. Fay c. A cable, rope, chain, or other flexible device for transmitting pull. Nichols, 1 d. To line pieces up in order to couple them together. Nichols, 1 e. See: plumbline lineage An imperfection in a crystal structure characterized by a series of line defects, but not extensive enough to form a grain boundary. CF: grain boundary; crystal defect. lineal foot 1800

A foot in length as distinguished from square foot or cubic foot. Crispin lineal travel Commonly used as a syn. for peripheral speed, as applied to bit rotation; also, a syn. for rope or cable speed, as applied to hoisting. Long lineament a. A significant line of landscape that reveals the hidden architecture of the rock basement. Lineaments are character lines of the Earth's physiognomy. AGI b. A topographic feature; esp., one that is rectilinear. Webster 3rd c. A topographic line that is structurally controlled. Lineaments are studied esp. on aerial photographs. Sometimes inappropriately called a linear. Billings linear Arranged in a line or lines; pertaining to the linelike character of some object or objects.-n. Not recommended as a syn. of lineament. AGI linear alkylbenzene sulfonate A high-quality, biodegradable detergent, obtained from lignite tar, which is derived from carbonizing coal at low temperatures. linear element A fabric element having one dimension that is much greater than the other two. Lineations are the common linear elements. CF: planar element; equant element. AGI linear expansion The increase in one dimension of a soil mass, expressed as a percentage of that dimension at the shrinkage limit to any given water content. ASCE linear model A function frequently used when fitting mathematical models to experimental variograms, often in combination with a nugget model. linear parallelism See: lineation linear schistosity 1801

A schistosity due to the parallel alignment of columnar or acicular crystals in rocks. linear shrinkage Decrease in one dimension of a soil mass, expressed as a percentage of the original dimension, when the water content is reduced from a given value to the shrinkage limit. ASCE linear structure See: lineation lineation A general, nongeneric term for any linear structure in a rock; e.g., flow lines, slickensides, linear arrangements of components in sediments, or axes of folds. Lineation in metamorphic rocks includes mineral streaking and stretching in the direction of transport, crinkles and minute folds parallel to fold axes, and lines of intersection between bedding and cleavage, or of variously oriented cleavages. Syn: linear structure; linear parallelism. AGI line brattice A partition placed in an opening to divide it into intake and return airways. See also: brattice line clinometer A borehole-survey clinometer designed to be inserted between rods at any point in a string of drill rods. CF: clinometer; end clinometer; plain clinometer; wedge clinometer. Long line defect An imperfection in crystal structure characterized by an atomic layer extending part way into a crystal structure. CF: crystal defect; edge dislocation. lined gold Gold foil backed with other metal. line drilling A term used in quarrying to describe the method of drilling and broaching for the primary cut. In this method, deep holes are drilled close together in a straight line by 1802

means of a reciprocating drill mounted on a bar. The webs between the holes are removed with a drill or a flat broaching tool; thus a narrow continuous channel cut is made. See also: broaching; controlled blasting. AIME, 1 line drop Loss in voltage owing to the resistance of conductors conveying electricity from a power station to the consumer. Hammond line electrode A series of electrodes put out along a straight line on the surface and electrically interconnected, approx. the condition of continuous electrical contact with the Earth along that line. Schieferdecker line lubricator See: line oiler line map See: planimetric map line of bearing a. The compass direction of the course a borehole follows. Long b. A syn. for strike as applied to a rock stratum. Long c. The direction of the strike. See: strike line of collimation The line of sight of the telescope of a surveying instrument, defined as the line through the rear nodal point of the objective lens of the telescope and the center of the reticle when they are in perfect alignment. See also: line of sight line of creep The path that water follows along the impervious surface of contact between the foundation soil and the base of a dam or other structure. Syn: path of percolation line of dip a. The direction in which an inclined borehole is pointed. Long b. The line of greatest inclination of a stratum from the horizontal plane. c. The direction of the angle of dip, measured in degrees by compass direction. It generally refers to true dip, but can be said of apparent dip as well. Syn: direction of dip 1803

line of force a. The straight line in which a force acts. Standard, 2 b. A curve in a field of force drawn so that at every point it has the direction of resultant force; specif., a line of magnetic force. Standard, 2 line of least resistance The shortest distance between the center line of a drill hole and the free rock face. Fraenkel line of outcrop The intersection of a stratum with the ground surface. Schieferdecker line of seepage The upper free-water surface of the zone of seepage. Syn: seepage line; phreatic line. ASCE line of sight The sighting or pointing line of a telescope, defined by the optical center of the objective and the intersection of crosshairs. See also: line of collimation line of thrust Locus of the points through which the resultant forces in an arch or retaining wall pass. Hammond line of tunnel The width marked by the exterior lines or sides of a tunnel. line oiler An apparatus inserted in a line conducting air or steam to an air- or steam-actuated machine that feeds small controllable amounts of lubricating oil into the air or steam. Also called lubricator; potato. Syn: air-line lubricator; line lubricator; oil pot; oiler; pineapple; pot. See also: atomizer liner

1804

a. A foot piece for uprights in timber sets. Nelson b. Timber supports erected to reinforce existing sets that are beginning to collapse due to heavy strata pressure. Nelson c. A string of casing in a borehole. Long d. See: lining lines Plumblines, not less than two in number, hung from hooks driven in wooden plugs. A line drawn through the center of the two strings or wires, as the case may be, represents the bearing or course to be driven on. Fay linesman An assistant to a surveyor. BS, 7 lines up The number of lines strung through the traveling block and crown block. Brantly, 2 line timbers Timbers placed along the sides of the track of a working place in rows on some predetermined plan. Kentucky line up a. A command signifying that the drill runner wants the hoisting cable attached to the drill stem, threaded through the sheave wheel, or wound on the hoist drum. Long b. To reposition a drill so that the drill stem is centered over and parallel to a newly collared drill hole. Long c. Regular linear pattern of peaks or troughs on a seismogram, such as occurs when a reflection comes in. Schieferdecker lingot An iron ingot mold. Standard, 2 lining a. A casing of brick, concrete, cast iron, or steel, placed in a tunnel or shaft to provide support. See also: tunnel lining b. In grinding of rocks and ores, a layer of wear-resistant material, used to protect rock breakers, shells of ball mills, chutes, launders, and other areas subject to abrasion. Special plastics, rubber, and acid-resistant alloys are used in vats, piping, and autoclaves, and for pump impellers exposed to abrasion and chemical attack. See also: scour protection c. A cover of clay, concrete, synthetic film, or other material, placed over all or part of the perimeter of a conduit or reservoir, to resist erosion, minimize seepage losses, withstand pressure, and improve flow. AGI d. 1805

Supporting the rock sides of a mine gallery is known as lining, and the material used in so doing is called the lining. Spalding e. The planks arranged against frame sets. Zern f. Refractory brickwork of furnace used to protect hearth, bosh, roof, or walls. Pryor, 3 g. The brick, concrete, cast iron, or steel casing placed around a tunnel or shaft as a support. Timber sets are not viewed as a lining. See also: brick walling; guniting; liner; permanent shaft support. Nelson lining mark Eng. A drill hole in the mine roof with a wooden plug driven into it from which to hang a plumbline. Fay lining sight An instrument consisting essentially of a plate with a longitudinal slot in the middle, and the means of suspending it vertically. It is used in conjunction with a plumbline for directing the courses of underground drifts, headings, etc. Webster 2nd lining up a mine In surveying, placing the sights for driving entries, drifts, or rooms nearer the working face. Fay linishing The operation of polishing as carried out on a linisher. This machine is designed for the polishing of flat objects and carries a flat revolving cloth belt whose surface is impregnated with a suitable abrasive material. Osborne link bar A lightweight steel bar extending faceward from the steel supports behind the conveyor. It supports the area between the conveyor and the coal on longwall faces where cutter loaders are carried on armored flexible conveyors. The joint and locking device may consist of a hinge pin and wedge. The standard bar can carry in cantilever a maximum tip load of about 2 st (1.8 t). In general, linked bars are stronger than corrugated straps and wooden bars, and their use is increasing. Nelson link conveyor A chain conveyor. Nelson linked veins

1806

An ore-deposit pattern in which adjacent, more or less parallel veins are connected by diagonal veins or veinlets. AGI Linkenbach table In mineral processing, a stationary round table onto which finely divided pulp (slimes) is fed from the center from a revolving feed box. A light wash of water follows, and lighter particles are washed downslope to a peripheral discharge launder. Behind this a heavier water flush displaces the settled heavier material (concentrates) and flushes it down to a bridging arrangement that delivers it to a separate discharge. Pryor, 3 link-plate belt A grizzly type of belt consisting of two strands of endless chain connected by through rods at each articulation, on which are carried a series of plates or bars mounted in a vertical plane for the purpose of rough screening while conveying. Syn: belt linnaeite a. An isometric mineral, 8[Co3 S4 ] ; commonly has small amounts of Ni, Fe, Cu; forms a series with polydymite; crystallizes in octahedra with cubic cleavage; metallic; steel gray tarnishing to copper red; in quartz sulfide veins; a source of cobalt. Also spelled linneite. b. The mineral group bornhardtite, carrollite, daubreelite, fletcherite, greigite, indite, linnaeite, polydymite, siegenite, truestedite, tyrrellite, and violarite. linneite Alternate spelling of linnaeite. linoleic acid An unsaturated fatty acid, CH3 (CH2 )4 CH = CH(CH2 )7 COOH , used as a collector in the flotation process. Pryor, 3; SME, 2 linolenic acid An unsaturated fatty acid, CH3 CH2 CH = CH CH2 CH = CH CH2 CH = CH(CH2 )7 COOH . Pryor, 3; SME, 2 linophyric Pertaining to porphyritic rocks in which the phenocrysts are arranged in lines or streaks. linseed fatty acid 1807

Byproduct of manufacture of linseed oil. Flotation agent used as collector, emulsifier, or stabilizer for davidite, a uranium mineral. Pryor, 3 linsey Lanc. A strong, striped shale and a streaky, banded sandstone or siltstone, interbedded in such a manner as to resemble a mixed linen and woolen fabric (linsey-woolsey). CF: whintin lintel A horizontal supporting member spanning a wall opening. Harbison-Walker Linz-Donawitz process A process for making steel from cast iron; it resembles the Bessemer process except for two important differences: (1) oxygen is used rather than air and (2) instead of blowing the gas through tuyeres submerged in the bath (as in the Bessemer converter), the oxygen stream impinges on the surface of the molten iron. Newton, 1 lionite See: tellurium lip a. The digging edge of a dredge bucket. Fay b. The cutting edge of a fixed-wing bit, such as the cutting edge on a fishtail bit. Long lip-and-gate builder One who constructs lips and gates that support and regulate flow of molten glass from furnace to glass-rolling machine. DOT liparite A syn. of rhyolite used by German and Soviet authors. Its name, given by Roth in 1861, is derived from the Lipari Islands, in the Tyrrhenian Sea. Not recommended usage; the much more widely used syn. rhyolite has priority by 1 yr. AGI lip of shaft Eng. The bottom edge of a shaft circle where it is open to the seam workings. Fay lip screen 1808

a. A common term applied to stationary screens installed in the loading chutes over which the coal flows as it is loaded into railroad cars for market. Mitchell b. A small screen or screen bars, placed at the draw hole of a coal pocket to take out the fine coal. liptinite See: exinite liptite Term used to describe a microlithotype consisting mainly of the exinite group of macerals and esp. of sporinite. Contains not less than 95% of exinite (liptinite) with thickness (bands) of exinite greater than 50 mu m recorded as liptite (sporite). Liptite (sporite) is a rare constituent of hard coal. CF: vitrite Liqnipel process A process for reducing high-moisture-content lignite from up to 40% moisture to about 10% moisture by pulverizing the raw coal, pelletizing the 14-mesh top size, thermally drying, and then mixing with a binder. The final product exhibits good handling and storage properties, and resists spontaneous combustion. liquation a. A method of recovering sulfur by liquefying it under pressure and heat, drawing off the molten sulfur, and allowing it to solidify. Fay b. The heating of a solid mixture until one of the constituents melts and can be separated from the solid remaining. Nelson liquid air Air in the liquid state but usually richer in oxygen than gaseous air. A faintly bluish, transparent, mobile, intensely cold liquid. Obtained by compressing purified air and cooling it by its own expansion to a temperature below the boiling points of its principal components, nitrogen (-195.8 degrees C, at 760 mm) and oxygen (-182.96 degrees C, at 760 mm). Used chiefly as a refrigerant and as a source of oxygen, nitrogen, and inert gases (as argon). Handbook of Chemistry and Physics, 2 liquidation grade The amount paid by the smelter or other purchaser per ton of ore mined. McKinstry liquid bituminous material Material having a penetration at 77 degrees F (25 degrees C), under a load of 50 g applied for 1 s, of more than 350. Urquhart 1809

liquid glass See: water glass liquid inclusion A partial syn. of fluid inclusion. AGI liquid-liquid extraction See: solvent extraction liquid measure Includes the following: 4 gills (gi) equal 1 pint (pt) or 0.47 L; 2 pt equal 1 quart (qt) or 0.95 L; 4 qt equal 1 gal or 3.785 L; 31-1/2 gal equal 1 bbl or 119.2 L; and 2 bbl equal 1 hogshead (hhd) or 238.5 L. Crispin liquid-phase sintering Sintering of a compact or loose powder aggregate under conditions where a liquid phase is present during part of the sintering cycle. ASTM liquid pressure The pressure of a liquid on the surface of its container or on the surface of any body in the liquid is equal to the weight of a column of the liquid whose height equals the depth of the liquid at that certain point. Kentucky liquids flowsheet A flowsheet to indicate the flow of liquids throughout a series of operations. BS, 5 liroconite A monoclinic mineral, Cu2 Al(AsO4 )(OH)4 .4H2 O ; soft; blue to green; occurs with malachite in the oxidized zone of copper deposits. Syn: lentil ore liskeardite A possibly orthorhombic mineral, (Al,Fe)3 (AsO4 )(OH)6 .5H2 O ; forms thin encrustations at Liskear, Cornwall, U.K. list 1810

a. Mid. Dull coal, sometimes dirty. Tomkeieff b. Derb. and Leic. A hard parting between coal seams. Arkell c. York. A weak shale or a thin bed of any kind of rock. Arkell d. Eng. A mine inspector's term for the schedule of particulars of accidents. Fay listing a. Fine shale or clay with glossy surfaces or slickensides due to crushing and relative movement. The rock may form a layer over a coal seam as clod; also applied to leather bed. Nelson b. See: lashing list mill In gem cutting, a wheel covered with list or cloth on which gems are polished. Also called list wheel. Standard, 2 list pan A perforated skimmer for skimming molten tin. Standard, 2 listric fault A curved downward-flattening fault, generally concave upward. Listric faults may be characterized by normal or reverse separation. AGI listy bed Soft freestone between the Chert Vein and House Cap in the Portland beds at Winspit, Purbeck, U.K. lithA prefix meaning stone or stonelike. litharge A tetragonal mineral, PbO ; red; dimorphous with massicot, which is yellow. Syn: lead ocher; lithargite. lithargite See: litharge lithia amethyst See: kunzite; spodumene. 1811

lithia emerald See: hiddenite; spodumene. lithia mica See: lepidolite lithic a. A syn. of lithologic, as in lithic unit. AGI b. Said of a medium-grained sedimentary rock, and of a pyroclastic deposit, containing abundant fragments of previously formed rocks; also said of such fragments. AGI c. Pertaining to or made of stone; e.g., lithic artifacts or lithic architecture. AGI lithic arenite a. A sandstone containing abundant quartz, chert, and quartzite, less than 10% argillaceous matrix, and more than 10% feldspar, and characterized by an abundance of unstable materials in which the fine-grained rock fragments exceed feldspar grains. The rock is roughly equivalent to subgraywacke. AGI b. See: lithic sandstone lithic graywacke A graywacke characterized by abundant unstable materials; specif. a sandstone containing a variable amount (generally less than 75%) of quartz and chert and 15% to 75% detrital-clay matrix, and having rock fragments (primarily of sedimentary or lowrank metamorphic origin) in greater abundance than feldspar grains (chiefly sodic plagioclase, indicating a plutonic provenance). AGI lithic sandstone A sandstone containing rock fragments in greater abundance than feldspar grains. Syn: lithic arenite lithic tuff An indurated deposit of volcanic ash in which the fragments are composed of previously formed rocks; e.g., accidental particles of sedimentary rock, accessory pieces of earlier lavas in the same cone, or small bits of new lava (essential ejecta) that first solidify in the vent and are then blown out. CF: crystal tuff lithidionite Alternate spelling of litidionite. See: litidionite 1812

lithifaction See: lithification lithification a. A compositional change in a coal seam from coal to bituminous shale or other rock; the lateral termination of a coal seam due to a gradual increase in impurities. AGI b. The conversion of a newly deposited, unconsolidated sediment into a coherent, solid rock, involving processes such as cementation, compaction, desiccation, and crystallization. It may occur concurrent with, soon after, or long after deposition. AGI c. A term sometimes applied to the solidification of a molten lava to form an igneous rock. See also: consolidation; induration. Syn: lithifaction lithionite See: lepidolite lithiophilite An orthorhombic mineral, 4[LiMnPO4 ] ; forms a series with triphylite; in granite pegmatites; an ore of lithium. lithiophorite A hexagonal or monoclinic mineral, (Al,Li)MnO2 (OH)2 ; powdery; black; occurs with other supergene manganese oxide minerals. lithiophosphate An orthorhombic mineral, Li3 PO4 ; in white to colorless masses in pegmatite; Kola Peninsula, Russia. lithium A soft, silvery-white metallic element of the alkali group, the lightest of all metals. Symbol, Li. Does not occur free in nature; is found combined in small amounts in nearly all igneous rocks and in the waters of many mineral springs. Lepidolite, spodumene, petalite, and amblygonite are the more important minerals containing it. The metal is corrosive and requires special handling. Used as an alloying agent, in the synthesis of organic compounds, and for nuclear applications. Handbook of Chemistry and Physics, 3 lithium borosilicate

1813

LiBSiO4 . Used in low-temperature enamels and as a component of high-temperature, corrosion-resistant coatings. Lee lithium mica See: lepidolite lithium niobate LiNbO3 ; a ferroelectric compound having the ilmenite structure and of potential interest as an electroceramic. Dodd lithium tantalate LiTaO3 ; a ferroelectric compound of potential value as a special electroceramic. The Curie temperature is above 350 degrees C. Dodd lithodeme A body of intrusive, pervasively deformed, or highly metamorphosed rock, generally nontabular and lacking primary depositional structures, and characterized by lithic homogeneity. It is mappable at the surface and traceable in the subsurface. For cartographic and hierarchical purposes, it is comparable to a formation. The name of a lithodeme combines a geographic term with a lithic or descriptive term, e.g., Duluth Gabbro. CF: suite lithofacies The rock record of any sedimentary environment, including both physical and organic characters. It is a mappable subdivision of a designated stratigraphic unit, distinguished from adjacent subdivisions on the basis of lithology. See also: facies lithofracteur Nitroglycerine mixed with siliceous earth, charcoal, sodium, and sometimes barium, nitrate, and sulfur. Fay lithogene Said of a mineral deposit formed by the process of mobilization of elements from a solid rock and their transportation and redeposition elsewhere. On a local scale, the process may be called a product of lateral secretion; on a larger scale, the deposit may be called a product of regional metamorphism. AGI lithogenesis 1814

The origin and formation of rocks, esp. of sedimentary rocks. Also, the science of the formation of rocks. CF: petrogenesis Adj: lithogenetic. AGI lithogenesy The science of the origin of minerals and the causes of their modes of occurrence. Standard, 2 lithogenetic Of or pertaining to the origin or formation of rocks. lithogeny See: lithogenesis lithoglyph A carving or engraving on a stone or gem; also, a stone or gem so engraved. Standard, 2 lithoglyptics The art of gem cutting; the cutting or engraving of precious stones or gems. Standard, 2 lithographic limestone A compact, dense, homogeneous, exceedingly fine-grained limestone having a pale creamy yellow or grayish color and a conchoidal or subconchoidal fracture. It was formerly much used in lithography for engraving and the reproduction of colored plates. See also: Solenhofen stone Syn: lithographic stone lithographic stone See: lithographic limestone lithographic texture A sedimentary texture of certain calcareous rocks, characterized by uniform particles of clay size and by an extremely smooth appearance resembling that of the stone used in lithography. AGI lithoid Rocklike or stonelike. 1815

lithoidal Said of the texture of some dense, microcrystalline igneous rocks, or of devitrified glass, in which individual constituents are too small to be distinguished with the unaided eye. AGI lithologic Adj. of lithology. Syn: lithic lithologic correlation The matching or linking up of identical rock formations, veins, or coal seams, exposed some distance apart, by lithology. See also: correlation Nelson lithology a. The character of a rock described in terms of its structure, color, mineral composition, grain size, and arrangement of its component parts; all those visible features that in the aggregate impart individuality to the rock. Lithology is the basis of correlation in coal mines and commonly is reliable over a distance of a few miles. Nelson b. The study of rocks based on the megascopic observation of hand specimens. In French usage, the term is synonymous with petrography. Holmes, 2 lithomarge A smooth, indurated variety of common kaolin, consisting at least in part of a mixture of kaolinite and halloysite. AGI lithophile a. Said of an element that is concentrated in the silicate rather than in the metal or sulfide phases of meteorites. Such elements concentrate in the Earth's silicate crust in Goldschmidt's tripartite division of elements in the solid Earth. CF: chalcophile; siderophile. AGI b. Said of an element with a greater free energy of oxidation per gram of oxygen than iron. It occurs as an oxide and more often as an oxysalt, esp. in silicate minerals. Examples are Se, Al, B, La, Ce, Na, K, Rb, Ca, Mn, U. Syn: oxyphile lithophosphor A mineral, such as barite, that becomes phosphorescent when heated. Syn: lithophosphore lithophosphore 1816

See: lithophosphor lithophysae Hollow, bubblelike, or roselike spherulites, usually with a concentric structure, that occur in rhyolite, obsidian, and related rocks. Sing: lithophysa. lithopone A white pigment composed of a mixture of barium sulfate, zinc sulfide, and zinc oxide. Hess lithospar A naturally occurring mixture of spodumene and feldspar. USBM, 6 lithosphere a. The solid outer portion of the Earth, as compared with the atmosphere and the hydrosphere. AGI b. In plate tectonics, an outer layer of great strength relative to the underlying asthenosphere for deformation at geologic rates. It includes the crust and part of the upper mantle and is about 100 km thick. AGI lithotope An area or surface of uniform sediment, sedimentation, or sedimentary environment, including associated organisms. CF: lithofacies AGI lithotype a. A rock defined on the basis of certain selected physical characters. AGI b. This term was proposed by C.A. Seyler in 1954 in a communication to the Nomenclature Subcommittee of the International Committee for Coal Petrology to designate the different macroscopically recognizable bands of humic coals. These bands were described by M.C. Stopes in 1919 as the four visible ingredients in banded bituminous coal. The following macroscopic bands are distinguished in humic coals: vitrain, clarain, durain, and fusain. IHCP lithoxyl Wood opal in which the original woody structure is observable; also petrified (opalized) wood. Also spelled lithoxyle; lithoxylite; lithoxylon. See also: wood opal litidionite 1817

Blue triclinic mineral, KNaCuSi4 O10 . litmus A blue dyestuff that turns red when treated by an acid and remains blue when treated by an alkali. Crispin litmus paper Absorbent paper dipped into a solution of litmus. Used to test solutions to determine whether they are acid or alkaline. Standard, 2 lit-par-lit Having the characteristic of a layered rock, the laminae of which have been penetrated by numerous thin, roughly parallel sheets of igneous material, usually granitic. Etymol: French, bed-by-bed. CF: injection gneiss; injection metamorphism. AGI Little Demon exploder Trade name for a small exploder that employs a manually operated electromagnetic generator as its source of power. It is approved for firing single shots in gassy mines and is in widespread use. Syn: one-shot exploder little giant A jointed iron nozzle used in hydraulic mining. See also: hydraulic monitor little winds a. Corn. A sump. Fay b. An underground shaft, sunk from a horizontal drift. A winze. Fay littoral Of or pertaining to a shore. A coastal region. Webster 2nd littoral current A current generated by waves breaking at an angle to the shoreline and that usually moves parallel to and adjacent to the shoreline within the surf zone. See also: longshore current littoral drift 1818

a. Applied to the movement along the coast of gravel, sand, and other material composing the bars and beaches. AGI b. Material moved in the littoral zone under the influence of waves and currents. AGI littoral zone In mine subsidence, the zone that embraces the disturbed strata lying round about and outside the mined strata. Briggs live boom A shovel boom that can be lifted and lowered without interrupting the digging cycle. Nichols, 2 liveingite A monoclinic mineral, Pb9 As13 S28 . Syn: rathite-II live load a. In drilling, a variable load suspended on the hoist line. Long b. In mechanics, a load that is variable, as distinguished from a load that is constant. Also called dynamic load. Long c. A load on a structure that may be removed or its position altered. See also: dead load d. It may not be a dynamic load, and it does not include wind load or earthquake shocks. Hammond live lode A lode containing valuable minerals. liverite Utah. A variety of bitumen, probably elaterite. Tomkeieff live roll grizzly A device for screening and scalping that consists of a series of spaced rotating, parallel rolls so constructed as to provide openings of a fixed size. See also: grizzly liver opal See: menilite liver ore 1819

A miners' term for cinnabar. liver pyrites A massive form of iron sulfide (marcasite and sometimes also pyrite and pyrrhotite) having a dull liver-brown color. liver rock A sandstone that breaks or cuts as readily in one direction as in another and that can be worked without being affected by stratification; a dense freestone that lacks natural division planes. AGI liverstone A variety of barite that gives off a fetid odor when rubbed or heated. livesite A clay mineral intermediate to kaolinite and halloysite; a disordered kaolinite. live steam Steam direct from the boiler and under full pressure. Distinguished from exhaust steam, which has been deprived of its available energy. Webster 3rd; Fay livingstonite A monoclinic mineral, HgSb4 S8 ; metallic lead gray. lixiviant A liquid medium that selectively extracts the desired metal from the ore or material to be leached rapidly and completely, and from which the desired metal can then be recovered in a concentrated form. SME, 1 lixiviation See: leaching lixivium See: leachate lizardite 1820

A trigonal and hexagonal mineral, Mg3 Si2 O5 (OH)4 ; kaolinite-serpentine group; polymorphous with antigorite, clinochrysotile, orthochrysotile, and parachrysotile; forms a series with nepouite; in platy masses as an alteration product of ultramafic rocks; the most abundant serpentine mineral. L-joint An approx. horizontal joint plane in igneous rocks. Syn: primary flat joint llano A term for an extensive tropical plain, with or without vegetation, applied esp. to the generally treeless plains of northern South America and the Southwestern United States. Etymol: Spanish. AGI load a. See: bit load b. The act or process of placing an explosive in a borehole; also, the explosive so placed. See also: charge load-bearing test Load-bearing tests may be divided into two types, horizontal and vertical. Both types require excavation of a test pit into the region that is being investigated. This test pit must be excavated with a minimum of blasting, with particular attention to the bearing surfaces to avoid disturbance of the foundation rock. Load-bearing tests are being used to an increasing extent as a source of information for the design of heavily loaded surface structures and have supplanted seismic tests where the foundation rock is highly shattered. Syn: horizontal load-bearing test load-bearing wall A wall carrying any load put upon it together with its own weight and the wind load. Hammond load binder A lever that pulls two grabhooks together, and holds them by locking over center. Nichols, 1 load cell Consists essentially of a hollow steel cylinder capped top and bottom by a steel plate. Strain gages are cemented on the inner wall of the cylinder in such a way that, as the cylinder is compressed, the strain gages will be distorted, with a resultant change in 1821

resistance. This instrument is designed for measuring the load transferred from the hanging wall onto props or other units used for support. Issacson load controller A device to control the load and prevent spillage on a gathering conveyor receiving coal or mineral from several loading points or subsidiary conveyors. The device is a simplified weightometer and is installed on the main belt a short distance before the intermediate loading point. When the main belt is fully loaded, the scale registers this fact and causes a break in the electrical circuit of the intermediate conveyor, which is stopped. Immediately after that, the flood loading on the main conveyor is finished, and the load controller operates and starts up the subsidiary conveyor. Nelson load dropper See: car runner; car dropper. loaded filter A graded filter placed at the foot of an earth dam or other construction, stabilizing the foot of the structure by virtue of its weight and permeability. Hammond loaded hole A drilled borehole in which explosive materials are loaded without priming the hole or including an initiator. loaded wheel A grinding wheel that has a glazed or clogged surface from particles of the material being ground. Crispin loader a. A mechanical shovel or other machine for loading coal, ore, mineral, or rock. Syn: mechanical loader scraper loader; shaker-shovel loader; shovel loader; cutter loader; gathering arm loader. Nelson b. The worker who loads coal, either by hand or by operating a loading machine, at the working face after the coal has been shot down; also keeps the working place in order. Syn: loader operator See also: hand loader c. In anthracite and bituminous coal mining, a laborer who shovels coal or rock, blasted from the working face in a mine, into cars or onto a conveyor belt from which cars are loaded at some point removed from the working place. May be designated as car loader; conveyor loader. Also called coal loader. d. In metal and nonmetal mining, one who shovels ore or rock, caved or blasted from the working face in a mine, into cars or onto a conveyor belt from which cars are loaded at some point removed from the working 1822

place. DOT e. See also: gun-perforator loader; tractor shovel. Syn: loader engineer; loader runner; loader operator.. loader boss a. In bituminous coal mining, a foreperson who supervises a crew of loaders loading coal onto a conveyor or into cars at working places in a mine. Also called loading boss; loading-unit boss. DOT b. In anthracite coal mining, a foreperson who supervises the loading of railroad cars with prepared coal. DOT loader engineer See: loader; boxcar loader. loader gate A gate road equipped with a gate conveyor or a gate-end loader; the gate to which the face conveyors deliver their coal. Nelson loader-off Eng. A man who regulates the sending out of the full cars from a longwall stall, or gate. Fay loader operator See: loader loader runner See: boxcar loader; loader. load-extension curve A line plotted from the results of a tensile test on metal, the loads being shown as ordinates and the elongations of the gage length as abscissae, thus relating the extension of the material under test to the applied load. See also: stress-strain curve load factor a. The ratio of the average compressor load during a certain period of time to the maximum rated load of the compressor. Lewis b. The ratio of the collapse load to the working load on a structure or section. Taylor c. In electric power engineering, the ratio of average electrical load to peak electrical load, usually calculated over a 1-h period. Lyman d. Average load carried by an engine, machine, or plant, expressed as a 1823

percentage of its maximum capacity. Nichols, 1 e. Ratio of average output during a period to maximum output during the period. Sometimes the ratio of output to maximum capacity. Strock, 2 load fold A plication of an underlying stratum, believed to result from unequal pressure and settling of overlying material. AGI load indicator A measuring device used to indicate the load or weight suspended on a drill hoisting line or cable. Long loading In ion exchange, sorption onto resins of metallic ions from a pregnant solution in loading cycle. Pryor, 3 loading boom a. In coal preparation, an overhanging steel chute for loading coal into rail wagons or lorries; usually capable of vertical movement as loading proceeds to minimize breakage. Nelson b. An adjustable conveyor used for lowering coal into cars with little breakage. Widely used for handling domestic sizes of bituminous coal. Mitchell c. A hinged portion of a conveyor that is designed to receive materials at a fixed level and to discharge them at varying levels; usually employed for loading coal into wagons. BS, 5 loading-boom operator See: conveyor man loading boss See: loader boss loading chute a. A three-sided tray for loading or for transfer of material from one transport unit to another. See also: chute b. A gravity chute used to convey coal from the pocket or the screen to the railroad car. Mitchell c. Used to direct material onto a conveyor. loading conveyor

1824

Any of several types of conveyors adapted for loading bulk materials, packages, or objects into cars, trucks, or other conveyors. See also: portable conveyor loading density The number of pounds of explosive per foot length of drill hole. Nelson loading equipment Mechanical shovels or other machines singly or in combination used to load excavated or stockpiled materials into trucks, mine cars, conveyors, or other transportation or haulage units. loading head That part of a loading machine that gathers the coal or rock and places it on the machine's elevating conveyor. loading-head man One who operates the loading device of any type of conveyance equipped with a selfloading head for the mechanical underground loading of coal or other mineral. Hess loading hopper A hopper used to receive and direct material to a conveyor. loading machine a. A generic term for any power-operated machine for loading mined coal or any other material into mine cars, conveyors, road vehicles, or bins. b. A machine for loading materials, such as coal, ore, or rock, into cars or other means of conveyance for transportation to the surface of the mine. See also: loader loading machine operator A person who operates a mobile loading machine. Syn: loading-machine runner loading-machine runner See: loading machine operator loading pan

1825

A box or scoop into which broken rock is shoveled in a sinking shaft while the hoppit is traveling in the shaft. A small hoist is used to lift and discharge the pans into the hoppit on its return to the shaft bottom. See also: box filling loading pick Eng. A pick for cleaning coal. Fay loading point a. The point where coal or ore is loaded into cars or conveyors, where a conveyor discharges into mine cars, or where a wagon or lorry is loaded. See also: transfer point b. N. of Eng. Where coal is transferred from a mother gate or trunk belt conveyor into tubs. Trist loading pole A nonmetallic pole used to assist the placing and compacting of explosive charges in boreholes. Atlas loading ramp A surface structure, often incorporating storage bins, used for gravity loading bulk material into transport vehicles. Nelson loading ratio In quarrying, the number of tons of rock blasted per 1 lb (0.454 kg) of explosive. The harder the rock, the lower the ratio. See also: explosive factor; explosive ratio. Also called powder factor. Streefkerk loadings Eng. Pillars of masonry carrying a winding drum or pulley. Fay loading shovel A mechanical shovel able to operate as a forklift truck, a crane, or a loader. See also: shovel loader loading station A device consisting of one or more plates, or a hopper receiving and placing material on the conveyor belt for transport. When such a loading station is located at the tail end, it is 1826

known as a tail-end loading station; when it is located along the intermediate section, it is known as an intermediate loading station. NEMA, 2 loading-unit boss See: loader boss loading weight Weight of a powder that is filled into a container under stated conditions. See also: bulk density load metamorphism A type of static metamorphism in which pressure due to deep burial has been a controlling influence, along with high temperature. CF: thermal metamorphism load-out To load coal or rock that is to be taken out of the mine. Fay loadstar See: lodestone loadstone Alternate spelling of lodestone. See also: lodestone load transfer The weight of the strata above every excavation is largely transferred to the coal pillars or packs in the vicinity. Attempts are made to control and facilitate this load transfer in the yield-pillar system and in double packing. See also: abutment; pressure arch. Nelson loam beater A rammer used in making a loam mold. Standard, 2 loam cake A disk of dried loam used to cover a loam mold; it has holes through which melted metal is poured and air escapes. Standard, 2 loaming 1827

A method of geochemical prospecting in which samples of soil or other surficial material are tested for traces of the metal desired, its presence presumably indicating a nearsurface orebody. AGI Lobbe Hobel An earlier type of rapid plow traveling at 70 ft/min (21.3 m/min) across the face. Nelson Lobbert lagging A lagging consisting of galvanized steel wire frames fastened to underground haulageway supports by special wire fasteners to provide a continuous lining. Nelson lobs Steps in a mine. Hess local cell A galvanic cell resulting from inhomogeneities between areas on a metal surface in an electrolyte. The inhomogeneities may be of physical or chemical nature in either the metal or its environment. See also: cell ASM, 1 local current A natural earth current of local origin, such as one arising from the oxidation of a sulfide deposit. A term used in electrical prospecting. AGI local extension The extension produced in a tensile test after the ultimate tensile stress has been passed and concentrated on part of the gauge length where a neck is formed. CTD local indicator plant Plants of wide geographic distribution having an affinity for absorbing certain metallic elements from the soil and which can be used in geochemical exploration to indicate presence of local concentrations of metals. CF: universal plant indicator local metamorphism Metamorphism caused by a local process; e.g., contact metamorphism or metasomatism near an igneous body, hydrothermal metamorphism, or dislocation metamorphism in a fault zone. CF: regional metamorphism AGI 1828

local shear failure Failure in which the ultimate shearing strength of the soil is mobilized only locally along the potential surface of sliding at the time the structure supported by the soil is impaired by excessive movement. ASCE local unconformity An unconformity that is strictly limited in geographic extent and that usually represents a relatively short period, such as one developed around the margins of a sedimentary basin or along the axis of a structural trend that rose intermittently while continuous deposition occurred in an adjacent area. It may be similar in appearance to, but lacks the regional importance of, a disconformity. CF: regional unconformity local vent A pipe or shaft to convey foul air from a plumbing fixture or a room to the outer air. Crispin local ventilation Ventilation of the drives and headings in mines by use of the pressure gradient of the main air current. Stoces locatable minerals A legal term that, for public lands in the United States, defines a mineral or mineral commodity that is acquired through the General Mining Law of 1872, as amended (30 U.S.C. 22-54, 161, 162, 611-615). These are the base and precious metal ores, ferrous metal ores, and certain classes of industrial minerals. Acquisition is by staking a mining claim (location) over the deposit and then acquiring the necessary permits to explore or mine. SME, 1 located Delimited by having the boundaries ascertained and monumented on the ground, identified by having a notice of location posted upon the land, and further proclaimed to the public by having such notice of location recorded in the manner customary under the rules for recording mining claims. Ricketts location a. The act of fixing the boundaries of a mining claim, according to law. b. The claim itself. c. The act of taking or appropriating a parcel of mineral land. It includes the posting of notices, the record thereof when required, and marking the boundaries so that 1829

they can be readily traced. The terms "location" and "mining claim" are synonymous, though a mining claim may consist of several locations. See also: mining claim d. Selecting or defining, on a map or in the field, the alignment of a road, rail track, or site of a shaft or mine; the actual route or site as fixed. See also: location plan; location survey. Nelson e. A spot or place where a borehole is to be drilled; a drill site. Long location and patent The location of a mining claim and patent for a mining claim are not governed by the same rules. The mining statutes expressly provide for the location of surface ground that must include the lode or claim as discovered; and a patent cannot grant any greater extent of surface ground than the location as made and marked by the surface boundaries. Ricketts location notice A written notice prominently posted on a claim, giving name of locator and description of its extent and boundaries. AGI location plan A map, drawn to a suitable scale, showing the proposed mine development, shafts, works, etc., in relation to existing surface features. See also: location location survey See: location location work Labor required by law to be done on mining claims within 60 days of location, in order to establish ownership. Syn: assessment work Weed, 2 loch An unfilled cavity in a vein. See also: vug lockage Water consumed in passing from the upper reach of a canal when a vessel passes through a lock. Hammond locked coil rope

1830

Made of specially formed wires assembled in layers of alternate lay about a wire core, which gives a smooth rope, and the entire surface is available for resisting wear. Such ropes are used in the United States for track cables on aerial tramways, and in England as hoisting ropes collieries. See also: wire rope locked-cycle test A series of repetitive batch tests in which the middling products generated in one test are added to the subsequent test to simulate the operations of a continuous process in which intermediate-grade materials are recycled. Each test is referred to as a "cycle." When equilibrium is reached in two or more cycles, depending on the sensitivity of the separation, the test is said to be "locked" or "balanced." SME, 2 locked particles Particles of coal or ore consisting of two or more minerals. Gaudin, 1 locked test In laboratory tests on small quantities of ore, a method in which any selected fraction of the product is added to a fresh batch of the sample, so that the cumulative effect of its retention can be studied under conditions that simulate a continuous process in which middlings are recirculated or partly used water or leach liquor is returned. See also: cyclic test locked-wire rope A rope with a smooth cylindrical surface, the outer wires of which are drawn to such shape that each one interlocks with the other and the wires are disposed in concentric layers about a wire core instead of in strands. Particularly adapted for haulage and ropetransmission purposes. Zern locker A short piece of round timber or iron rod for inserting between the spokes of a tram wheel to retard its movement. Also called lolley; sprag. Nelson locking bolts Bolts of any type used for locking parts in position. Crispin locknut

1831

The nut securing the feed gears in the feeding mechanism in a gear-feed swivel head on a diamond drill; also, any extra nut used to secure a principal nut. Also called jamnut; jambnut. Long lock paddle A sluice whereby a lock chamber is emptied or filled. Hammond lockpin Any pin or plug inserted in a part to prevent play or motion in the part so fastened. Crispin lock sill A raised portion of the floor of a lock chamber, forming a stop against which the lock gates bear when they are shut. Hammond lockup clutch A clutch that can be engaged to provide a nonslip mechanical drive through a fluid coupling. Nichols, 1 locomotive An electric engine, operating either from current supplied from trolley and track or from storage batteries carried on the locomotive. The locomotive may be powered by battery, diesel, compressed air, trolley, or some combination such as battery-trolley or trolleycable reel. Used to move empty and loaded mine cars in and out of the mine. BCI locomotive arches Arches built of special refractory shapes, supported by water-circulating members. locomotive brakeman In anthracite and bituminous coal mining, one who works on trains or trips of cars hauled by locomotive or motor, as distinguished from rope haulage. Also called locomotive helper; locomotive patcher; motor brakeman; motor nipper; poleman. DOT locomotive garage An elongated recess in an intake airway of a mine for servicing locomotives. It contains two or three rail tracks (with pit space under one), good lighting, lifting equipment, oils, 1832

benches, and tools. Where battery locomotives are used, the garage will serve as a charging station. Syn: underground garage; battery charging station. Nelson locomotive gradient The statutory maximum gradient for locomotive haulage is 1:15, but ordinarily the practical limit is about 1:25. Roads driven specially for locomotives are normally graded about 1:400 in favor of the load, unless a steeper gradient is required for drainage. Nelson locomotive haulage The transport of coal, ore, workers, and materials underground by means of locomotivehauled mine cars. The locomotive may be powered by battery, diesel, compressed air, trolley, or some combination such as battery-trolley or trolley-cable reel. See also: compressed-air locomotive; haulage; underground haulage. Nelson locomotive helper See: locomotive brakeman locomotive pan brick Shapes, used to build a burner enclosure, flash wall, and protecting walls for the water legs. locomotive patcher See: locomotive brakeman locomotive resistance The combined resistance caused by the friction of the journal and the wheel tread. It can range from 12 to 20 lb (5.44 to 9.07 kg), but for practical purposes may be taken as 15 lb (6.8 kg), as the locomotive represents only a small portion of the total tractive effort. Kentucky lode A mineral deposit consisting of a zone of veins, veinlets, disseminations, or planar breccias; a mineral deposit in consolidated rock as opposed to a placer deposit. Syn: lead See also: vein or lode claim lode claim 1833

a. That portion of a vein or lode, and of the adjoining surface, that has been acquired by a compliance with the law, both Federal and State. Any dispute as to whether a given parcel of land is a vein or a lode is a question of fact to be determined by those experienced in mining, and it cannot be determined as a matter of law. Ricketts b. See: vein or lode claim c. A mining claim on an area containing a known vein or lode. CF: placer claim lode plot A horizontal lode. lodestone a. A variety of magnetite showing spontaneous magnetization because of preferential alignment of magnetic domains within a crystal or mass of crystals. If permitted to do so, lodestone will align its polarity with the geomagnetic field, e.g., floating on a piece of wood in water as an early type of compass for navigation. Also spelled loadstone. Syn: leading stone; Hercules stone; loadstar. b. An intensely magnetized rock or ore deposit. See also: magnetite lodestuff Minerals included in a lode or vein, including economically valueless gangue. See also: veinstuff lode tin Tin ore (cassiterite) occurring in veins, as distinguished from stream tin or placer tin. CF: stream tin lodge a. A reservoir of any size used for holding water in a mine. A sump or standage. Also called lodgement. See also: pound b. Eng. A subterranean reservoir for the drainage of the mine made at the shaft bottom, in the interior of the workings, or at different levels in the shaft. Fay c. Scot. A cabin at the mine shaft for workers. Fay d. The room or flat at the shaft into which the pushers or trammers empty their loads. Standard, 2 e. S Wales. The local branch of the coal miners' union. Nelson f. A pump room, near the pit bottom or other main pumping station. Nelson lodgment level Scot. A room driven from a level a short distance to the dip and used for storage of water. A sump. Fay 1834

loellingite See: loellingite loess A widespread, nonstratified, porous, friable, usually highly calcareous, blanket deposit (generally less than 30 m thick), consisting predominantly of silt with subordinate grain sizes ranging from clay to fine sand. It covers areas extending from north-central Europe to eastern China as well as the Mississippi Valley and Pacific Northwest of the United States. Loess is generally buff to light yellow or yellowish brown; often contains shells, bones, and teeth of mammals; and is traversed by networks of small narrow vertical tubes (frequently lined with calcium carbonate concretions) left by successive generations of grass roots, which allow the loess to stand in steep or nearly vertical faces. Loess is now generally believed to be windblown dust of Pleistocene age. CF: adobe AGI loeweite Alternate spelling of loeweite. Loewinson-Lessing classification A chemical classification of igneous rocks (into the four main types--acid, intermediate, basic, and ultrabasic) based on silica content. AGI Lofco car feeder An appliance for controlling mine cars at loading points, for marshalling trains, and for loading cars into cages, tipplers, and other points. It consists of a carrying chain running between the rails. The dummy or live axles of the cars are held firmly by the chain's profile, and an overload slipping action is provided. See also: feeder lofthead An overhead cavity caused by a fall of roof. Nelson lofting a. S. Wales. An old or disused heading over the top of another one. Fay b. N. of Eng. See: lacing c. Scot. Wood filling up vacant space on top of crowns or gears. Fay d. Timbers, usually old, laid across the caps of steel frames or sets in a working to support the roof. Webster 2nd log 1835

The record of, or the process of recording, events or the type and characteristics of the rock penetrated in drilling a borehole, as evidenced by the cuttings, core recovered, or information obtained from electric, sonic, or radioactivity devices. Also called logged; logging. See also: well log Logan slabbing machine This machine consists essentially of two horizontal cutting chains, one working at the base of the coal seam and the other at a distance from the floor; a third cutter chain is mounted vertically on a shearing jib at right angles to the other two and shears off the coal at the back of the cut. The upper jib breaks the coal up into loadable size, and a short conveyor transfers it to the face conveyor. Similar in principle to the A.B. MecoMoore cutter-loader. Mason logbook A book in which the official record of events or the type and characteristics of the rock penetrated by the borehole is entered. Also called journal; journal book. CF: log logging chain A chain composed of links of round bar pieces curved and welded to interlock, with a grabhook at one end and a round hook at the other. Nichols, 1 logging tongs Tongs with end hooks that dig in when the tongs are pulled. Nichols, 1 log washer A slightly slanting trough in which revolves a thick shaft or log, carrying blades obliquely set to the axis. Material is fed in at the lower end, water at the upper. The blades slowly convey the lumps of material upward against the current, while any adhering clay is gradually disintegrated and floated out the lower end. Liddell Lohmannizing A process by which a protective zinc coating is amalgamated to a base-metal sheet. Liddell loipon A term proposed by Shrock (1947) for a residual surficial layer produced by intense and prolonged chemical weathering and composed largely of certain original constituents of the source rock. Typical accumulations of loipon are the gossans over orebodies, bauxite 1836

deposits in Arkansas, terra rossa deposits of Europe, and duricrust of Australia. Etymol: Greek, residue. Adj: loiponic. AGI lok batanite Variety of bituminous material derived from a mud volcano. Tomkeieff loellingite a. An orthorhombic mineral, 2[FeAs2 ] ; basal cleavage; metallic; sp gr, 7.45; in quartz veins; a source of arsenic. Also spelled loellingite, lollingite. Syn: leucopyrite; glaucopyrite; geyerite. b. The mineral group costibite, loellingite, nisbite, rammelsbergite, safflorite, and seinaejokite. loma A term used in the Southwestern United States for an elongated, gentle swell or rise of the ground (as on a plain), or a rounded, broad-topped, inconspicuous hill. Etymol: Spanish, hillock, rising ground, slope. AGI lomonosovite A triclinic mineral, Na2 Ti2 Si2 O9 .Na3 PO4 ; in alkalic pegmatites and sodalite syenites; Kola Peninsula, Russia. long awn A direction of less than 45 degrees to the main natural line of cleat or cleavage in the coal. Also spelled horn. CF: short awn long clay A highly plastic clay. Syn: fat clay long column A column that fails by buckling, as distinct from crushing, when overloaded. CF: short column long hole Underground boreholes and blastholes exceeding 10 ft (3.05 m) in depth or requiring the use of two or more lengths of drill steel or rods coupled together to attain the desired depth. CF: long-hole drill 1837

long-hole blasting Method of blasting, employing diamond drills or extension steel drills with tungsten carbide bits, applied to ore-winning operations where conditions are suitable. The essential requirements from the practical and economic points of view are (1) a large orebody or wide regular vein, (2) a strong country rock, and (3) a good parting between the ore and the rock to avoid undue contamination of the ore. Holes to take cartridges up to 2 in (5.1 cm) in diameter may be drilled. Since the drilling of long holes is relatively expensive, high-strength, high-density gelatinous explosives are usually employed so that the maximum burden can be placed on each hole. For this reason also, the largest diameter of explosive cartridge that can be loaded into the holes should be used to obtain the greatest possible loading density. McAdam, 2 long-hole drill A rotary- or percussive-type drill used to drill underground blastholes to depths exceeding 3 m. CF: long hole long-hole infusion There are two methods: (1) Long holes are drilled parallel to the coal face. Charges of Hydrobel explosive are spaced along the holes and fired under water pressure. The object is to loosen the coal and allay the dust along the entire face in one operation. See also: pulsed infusion shot firing about 40 ft (12.2 m) long in the line of advance of the workings. The holes are not charged with explosive and fired but only subjected to water pressure up to 3,000 psi (20.7 MPa) to loosen the coal and allay the dust in the cleats. The holes may be drilled during weekends and of a length about equal to the weekly advance of the face. Nelson long-hole jetting A hydraulic mining system consisting essentially of drilling a hole down the pitch of the vein, replacing the drilling head with a jet cutting head, and then retracting the drill column with the jets in operation to remove the coal. Coal cut loose by the jets drops to a flume drift and is carried by water to a screening and loading plant. Coal Age, 3 longitudinal fault A fault whose strike is parallel with that of the general structural trend of the region. AGI longitudinal fissure A fissure that is parallel with the strike of the deposit. Stoces longitudinal joint 1838

A steeply dipping joint plane in a pluton that is oriented parallel to the lines of flow. Syn: S-joint; bc-joint. AGI longitudinal trace A trace on the ground motion record representing the component of motion in a horizontal plane and in the direction of the seismic wave travel direction. Syn: radial axis longitudinal valley See: strike valley longitudinal velocity See: modulus of elasticity longitudinal wave An elastic wave in which the displacements are in the direction of wave propagation. Syn: P wave; primary wave. AGI long (lazy) flames Partially aerated flames, particularly when aerated in stages. Nonturbulent flow. Francis, 2 Longmaid-Henderson process Method of recovering copper from burned sulfides, by roasting with rock salt and using the issuing gases, after condensation, to leach the chloridized residue. Copper then dissolved is precipitated from the leach liquor onto scrap iron. Pryor, 3 long piggyback conveyor An appliance to provide a constant flow of coal from a continuous miner to the main haulage system. It consists of a conveyor slung under the tail end of the loader and running on a bogey straddling the heading conveyor so that it can telescope over it. Nelson long-pillar work Coal winning in three stages in underground mining. First, large pillars are left as the face is advanced by means of drives. Second, parallel drives connect these drives and form large blocks. Finally, the pillars so formed are mined. Pryor, 3 1839

long-range order The property of crystal structures wherein atomic particles show periodicity over large numbers of atomic diameters and each atomic particle has specific relationships with lattice points. CF: short-range order; disorder. See: superlattice; superstructure. long run To fill or nearly fill the core barrel with core on a single trip into the borehole. CF: short run long-running thermal precipitator A dust-sampling instrument designed by the Mining Research Establishment of Great Britain that operates over periods of up to 8 h and collects only respirable dust that is selected aerodynamically during the sampling process. The respirable fraction is selected by drawing the dust through a horizontal duct elutriator that simulates the acting principle of the human nose and respiratory passages in that the larger and faster-falling particles are caught by the processes of settlement and impingement. Roberts, 1 long section A section of land that contains more than 640 acres (256 ha). Williams long-shank chopping bit A steel chisel-edged chopping bit having a longer and heavier-than-normal shank, designed to give added weight and directional stability when chopping an angle hole through overburden. Long longshore current A current in the surf zone, moving generally parallel to the shoreline, generated by waves breaking at an angle with the shoreline. Syn: littoral current longshore drift See: beach drift long tom A trough for washing gold-bearing earth. It is longer than a rocker. Webster 3rd; Fay longues tailles 1840

Fr. See: longwall longwall a. A long face of coal. Stoces b. A method of working coal seams believed to have originated in Shropshire, England, toward the end of the 17th century. The seam is removed in one operation by means of a long working face or wall, thus the name. The workings advance (or retreat) in a continuous line, which may be several hundred yards in length. The space from which the coal has been removed (the gob, goaf, or waste) either is allowed to collapse (caving) or is completely or partially filled or stowed with stone and debris. The stowing material is obtained from any dirt in the seam and from the ripping operations on the roadways to gain height. Stowing material is sometimes brought down from the surface and packed by hand or by mechanical means. See also: longwall advancing; longwall retreating. Also known as longwork; Shropshire method; combination longwall; and Nottingham or Barry system. Syn: combination longwall Nelson; Fay c. Opposite of shortwall. See also: longwall mining longwall advancing A system of longwall working in which the faces advance from the shafts toward the boundary or other limit lines. In this method, all the roadways are in worked-out areas. See also: longwall longwall coal cutter Compact machine, driven by compressed air or electricity, that cuts into the coal face with its jib at right angles to its body. See also: longwall machine longwall machine A power-driven machine used for shearing coal on relatively long faces. See also: longwall coal cutter longwall miner In bituminous coal mining, one who extracts coal from seams by a specialized method known as longwall mining. In this method, all coal is extracted as the work progresses, and the roof caves behind the working face. longwall mining a. A full-extraction method for mining large panels of coal. b. A system of mining in which all the minable coal is recovered in one operation. Hudson c. A method of mining flat-bedded deposits, in which the working face is advanced over a considerable width at one time. See also: longwall Pryor, 3 1841

longwall peak stoping A method of underland stoping in which rapid advance of the face is maintained, and by working the faces at an angle of 60 degrees to the strike, the peak travels down the dip at twice the rate of the face advance. This method was introduced on the Witwatersrand for stoping below 5,000 ft (1,524 m), where rapid face advance resulting from the closer spacing of holes reduces the incidence of rock bursts. Higham longwall pillar working The extraction of the coal pillars formed by a pillar method of working, by a longwall face, which can be advancing or retreating. Where the crush is not excessive, this method is more efficient and often safer than extracting each pillar individually. Nelson longwall retreating A system of longwall working in which the developing headings are driven narrow to the boundary or limit line and then the coal seam is extracted by longwall faces retreating toward the shaft. In this method, all the roadways are in the solid coal seam and the waste areas are left behind. See also: longwall; mechanized heading development. Nelson lonkey Eng. The best Yorkshire sandstone, Rossendale District. CF: lunker Arkell loodwin Burma. Ruby mines in which fissures, caves, and hollows in the limestone, filled with detritus from its disintegration, are followed, and their contents, often cemented or buried under recent travertine, are extracted and washed. Hess looking-glass ore Lustrous hematite, Fe2 O3 . Specular iron ore; iron glance. Mohs hardness, 6; sp gr, 5.2. Pryor, 3 lool A vessel to receive ore washings. Standard, 2 loom Eng. A variant of loam, esp. in the Thames Valley; applied to Thanet sand and dredged mud used for cement. Arkell 1842

loop circuit A term used when two positive wires are installed in divergent directions but later come close enough together to be connected. They then form a series or so-called loop circuit. CF: parallel blasting circuit Kentucky loop drag An eye at the end of a rod through which tow is passed for cleaning boreholes. looper In ore dressing, smelting, and refining, a laborer who attaches loops (folded copper sheets or strips) to starting sheets so that sheets can be suspended in electrolytic tanks. Also called looper puncher. DOT loop haulage A system used when a continuous supply of cars must be supplied to a loading station. In this system, the empty cars are simply coupled to one end of the standing cars, which are pulled forward by a hoist with the rope attached to a clip fixed to the side of the cars. The rope is pulled back by hand for a distance of three or four car-lengths, and the process is repeated frequently as the end of the rope approaches the hoist. Wheeler, H.R. looping The running together of ore matter into a mass when the ore is only heated for calcination. CF: loup looping mill Consists of one or more trains of alternating two-high stands. As the piece being rolled emerges from one stand, it is turned through 180 degrees and entered into the next stand and similarly into the succeeding stands. In some mills, the looping is performed by hand, while in others it is done mechanically by means of repeaters or looping channels. Osborne loop-type pit bottom A pit bottom layout in which the loaded cars are fed to the cage from one side only and the empties are returned to the same side by means of a loop roadway. The loop arrangement provides more standage room for cars and is more suitable for multideck cages. When the coal reaches the pit bottom from two sides, a double-loop layout may be adopted. Nelson 1843

loopway A double-track loop in a main single-track haulage plane at which mine cars may pass. A loopway located close to the face or loading machine enables a train of empty cars to be stationed in the loop, while the loaded cars are run straight out on the main single track. Nelson loose Loose, or crick, is a vertical joint affecting only the lower strata in a oolite quarry, Northamptonshire, U.K. Syn: crick loose end a. A gangway in longwall working, driven so that one side is solid ground while the other opens upon old workings. CF: fast end b. Coal prepared by cutting, or that coal that is certain to be loosened by a shot. Fay c. The limit of a stall next to the goaf, or where the adjoining stall is in advance. Fay loose goods Industrial diamonds as purchased from a diamond supplier in bulk. CF: loose stone loose ground a. Broken, fragmented, or loosely cemented bedrock material that tends to slough from sidewalls into a borehole. Also called broken ground. CF: breccia b. As used by miners, rock that must be barred down to make an underground workplace safe; also fragmented or weak rock in which underground openings cannot be held open unless artificially supported, as with timber sets and lagging. CF: broken ground c. A shattered rock formation, or a formation crisscrossed with numerous, closely spaced, uncemented joints and cracks. Long loose-needle traversing A method of traversing in which the magnetic bearings of survey lines are separately obtained by reference to the magnetic needle. BS, 7 loosening bar An implement for loosening a pattern from a sand mold. Standard, 2 loose rails

1844

Aust. Rails that can be lifted and placed across a permanent line when desired to run skips across it. Fay loose rock See: loose ground looses Vertical joints affecting only the lower strata in the ooelite quarries, Northamptonshire, U.K. Also called cricks. loose stone a. A diamond insecurely bonded in a bit matrix. Long b. A diamond detached from a bit and lying on the bottom of a drill hole. Long c. An unset industrial diamond. CF: loose goods loose yards Measurement of soil or rock after it has been loosened by digging or blasting. Nichols, 1 loosing S. Staff. Lowering a cage, etc., into a shaft or pit. Fay loparite A possibly orthorhombic mineral, (Ce,Na,Ca)2 (Ti,Nb)2 O6 ; perovskite group; pseudocubic; Kola Peninsula, Russia. lopezite A triclinic mineral, K2 Cr2 O7 ; forms minute orange-red balls in nitratine in Chile. lopolith A large, concordant, typically layered igneous intrusion, of planoconvex or lenticular shape, that is sunken in its central part owing to sagging of the underlying country rock. Syn: funnel intrusion loran Any of various long-range radio position-fixing systems by which hyperbolic lines of position are determined by measuring the difference in arrival times of synchronized 1845

pulse signals from two or more fixed transmitting radio stations of known geographic position. Loran fixes may be obtained at a range of 1,400 nmi (2,593 km) at night. CF: shoran Etymol: long-range navigation. AGI lorandite A monoclinic mineral, TlAsS2 ; red; forms modified tabular or prismatic crystals with one perfect cleavage. loranskite A mineral, (Y,Ce,Ca)ZrTaO6 (?). lorettoite A tetragonal artifact, Pb7 O6 Cl2 . lorry a. York. A movable bridge over a shaft top upon which the bucket is placed after it is brought up for emptying. Fay b. A car used on mine tramways, or at coke ovens. Fay c. Gr. Brit. A long wagon having a very low platform and four very small wheels. Standard, 2 Los Angeles abrasion testing machine A machine for measuring abrasion resistance or toughness. It consists of a closed hollow steel cylinder 28 in (71.12 cm) in diameter and 20 in (50.8 cm) long mounted for rotation with its axis horizontal. The sample being tested and a charge of steel spheres are tumbled during rotation by an internal shelf. AIME, 1 lose a. Eng. To work a seam of coal, etc., up to where it dies out or is faulted out of sight. This is called "losing the coal." Fay b. To be unable to work out a pillar on account of thrust, creep, gob fire, etc. Fay c. A pit shaft is said to be "lost" when it has run in or collapsed beyond recovery. Fay loseyite A monoclinic mineral, (Mn,Zn)7 (CO3 )2 (OH)10; soft; bluish white; at Franklin, NJ. losing iron See: furnace losing-the-iron 1846

loss of vend Difference between weight of raw coal and that of salable products, expressed as a percentage. Pryor, 3 loss on ignition As applied to chemical analyses, the loss in weight that results from heating a sample of material to a high temperature, after preliminary drying at a temperature just above the boiling point of water. The loss in weight upon drying is called free moisture; that which occurs above the boiling point of water, loss on ignition. Harbison-Walker lost circulation The condition during rotary drilling when the drilling mud escapes into porous, fractured, or cavernous rocks penetrated by the borehole and does not return to the surface. AGI lost closure The amount of closure of the walls of a stope that occurs before supports have been placed and begin to oppose that closure. Spalding lost core The portion of a core that is not recovered. It may be the soft rock that crumbles and falls from the core barrel or the solid piece or pieces of core that drop to the bottom of a borehole after slipping out of the core barrel while the drill string is being pulled from the drill hole. Long lost corner A corner whose position cannot be determined, beyond reasonable doubt, either from traces of the monument, or by reliable testimony relating to it; and whose location can be restored only by surveying methods and with reference to interdependent existent corners, by mutual agreement of abutters, or by court decision. Seelye, 2 lost hole A borehole in which the target could not be reached because of caving, squeezing, loose ground, or inability to recover lost tools or junk. Long lost level

1847

Corn. A level or gallery driven with an unnecessarily great departure from the horizontal. Fay lost river a. A dried-up river in an arid region. b. A river in a karst region that drains into an underground channel. lost thread method See: string survey lost water See: lost circulation loudspeaker face telephone An intrinsically safe public address system developed for coal face communications. Up to 20 individual units, each containing a telephone handset and speaker, can be coupled together along the face and gate roads by a five-way cable. Instructions, requests, etc., made into any one of the handsets are broadcast simultaneously over all the loudspeakers. See also: signaling system loup The pasty mass of iron produced in a bloomery or puddling furnace. CF: looping loupe Any small magnifying glass or lens mounted for use in the hand, held in the eye socket, or attached to spectacles and used to study minerals and rocks. Also spelled lupe, loup, loop. louver cleaner In ore dressing, smelting, and refining, one who trims carbon anodes and cleans louvers to minimize electrical resistance in magnesium refining cells. DOT louvers Overlapping and sloping slats arranged to prevent entrance or exit of a portion of an air stream. Louvers are sometimes used as a regulator in place of a sliding or other adjustable door. 1848

love arrows See: fleches d'amour love stone See: aventurine Love wave a. A transverse wave propagated along the boundary of two elastic media that both have rigidity; i.e., both media must be capable of propagating transverse waves. AGI b. A surface seismic wave in which the particles of an elastic medium vibrate transverse to the direction of the wave's travel, with no vertical component. AGI c. A type of surface wave having a horizontal particle motion that is transverse to the direction of propagation. Its velocity depends only on density and rigidity modulus, and not on bulk modulus. It is named after A.E.H. Love, the English mathematician who discovered it. Syn: Q wave; Querwellen wave. AGI lovozerite The mineral group imandrite, kazakovite, koashvite, lovozerite, petarasite, tisinalite, and zirsinalite. low a. A former stream channel in a coalbed, filled with sandstone, clay, and shale. CF: cutout b. A general term for such features as a structural basin, a syncline, a saddle, or a sag. CF: high c. Indicates that a crystal structure is the low-temperature dimorph for the crystal compound. low-alumina silica brick Special brick in which the total alumina, titania, and alkali are significantly lower than in regular silica brick. low-angle fault A fault with a dip of 45 degrees or less. CF: high-angle fault AGI low bed A machinery trailer with a low deck. Nichols, 1 low blast 1849

A blast delivered to a smelting furnace at low pressure. Standard, 2 low coal Coal occurring in a thin seam or bed. Fay low-deflagrating explosive Another name for black powder. Kentucky Lowden drier Mechanized drying floor used for ores or concentrates. Reciprocating rakes move the material gently over steel plates heated from below. Pryor, 3 low-density explosive Explosive designed for use in mining, where it is required to blast with the least amount of shattering and/or to reduce explosive cost. The density of ordinary explosives may be decreased by (1) loose packing, (2) an alteration in the granular state of the ammonium nitrate, and (3) the impregnation of woodmeal or suitable substitutes. By decreasing the density of an explosive the same weight of explosive is used, but owing to its greater bulk the explosive effects are distributed over a greater area, thus producing a less shattering effect. low-discharge ball mill One with a substantial downslope between the trunnion-high feed end and the peripheral discharge end. This facilitates the brisk movement of ore through the mill. Pryor, 3 low doors Scot. The lowest of two or more landings in a shaft. Fay low-duty fire clay brick A fire-clay refractory having a pyrometric cone equivalent not lower than 19 and a minimum modulus of rupture of 600 psi (4.1 MPa). ARI loeweite A trigonal mineral, Na12 Mg7 (SO4 )13 .15H2 O ; white; water soluble. Also spelled loeweite. lower 1850

Pertaining to rocks or strata that are normally below those of later formations of the same subdivision of rocks. The adj. is applied to the name of a chronostratigraphic unit (system, series, stage) to indicate position in the geologic column and corresponds to early as applied to the name of the equivalent geologic-time unit; e.g., rocks of the Lower Jurassic System were formed during the Early Jurassic Period. The initial letter of the term is capitalized to indicate a formal subdivision (e.g., Lower Devonian) and is lowercased to indicate an informal subdivision (e.g., lower Miocene). The informal term may be used where there is no formal subdivision of a system or of a series. CF: upper; middle. AGI lower break The lower bend of either a terrace or a monocline, also known as the foot or the lower change of dip. See also: foot lowering conveyor Any type of vertical conveyor for lowering objects at a controlled speed. See also: arm conveyor; suspended tray conveyor; vertical reciprocating conveyor. lowering skips Used in some river tipples to let the coal down into the barges. Also known as weigh pans. Mitchell lowering tongs Long-handled, plierlike device similar to a certain type of blacksmith tongs used to handle wash or drill rods in place of a safety clamp in shallow borehole drilling. Syn: brown tongs; knife dog. lower leaf Scot. The lower portion of a seam of coal that is worked in two sections or leaves. Fay lower limit of flammability The smallest quantity of combustible gas that, when mixed with a given quantity of air (or oxygen), will just support a self-propagating flame. Francis, 2 lower liquid limit In soil mechanics, the moisture content at which soil changes from plastic to liquid. Pryor, 3 1851

lower plastic limit Moisture content of soil at which it changes from a plastic to a semisolid state. Pryor, 3 lower plate See: footwall lowest visible red-heat Common division of the color scale--about 887 degrees F (475 degrees C). low explosive An explosive in which the change into the gaseous state is effected by burning and not by detonation as with high explosives. Blasting powder (black powder or gunpowder) is the only low explosive in common use. It requires no detonator but is ignited by means of a safety fuse. Also called propellant. Nelson low-freezing dynamites Dynamites made by replacing part of the nitroglycerin of straight dynamites with some ingredient to render the dynamite incapable of freezing under ordinary conditions of use. The freezing point is depressed by adding nitro substitution compounds, such as nitrated sugars, nitrotoluene, nitrated polymerized glycerin, or ethylene glycol dinitrate. Lewis low-freezing explosive See: polar explosive low gear a. See: slow gear b. Mining and/or drilling operations carried on at a leisurely pace and at less-than-normal output per worker shift. Long c. When applied to a screwfeed-type drill, the pair of feed gears in the feed mechanism that advances the bit the least amount for each revolution of drill drive rod and/or coupled drill stem. d. When applied to speed at which the drill motor rotates the drill stem, the transmission-gear position giving the lowest number of bit revolutions per minute per engine revolutions per minute; corresponds to low gear in an automobile. low-grade a. An arbitrary designation of dynamites of less strength than 40%. It has no bearing on the quality of the materials, as they are of as great purity and high quality as the ingredients in a so-called high-grade explosive. Fay b. Sometimes applied to poor- or 1852

low-quality drill diamonds. Long c. Pertaining to ores that have a relatively low content of metal compared with other richer material from the same general area. Also designates coal high in impurities. Low-grade metamorphism refers to metamorphism at a relatively low temperature and/or pressure. CF: high-grade Stokes d. See: lean ore low-grade coal Combustible material that has only limited uses owing to undesirable characteristics (for example, ash content or size). BS, 5 low-heat cement A cement in which there is only limited generation of heat during setting, achieved by modifying the chemical composition of normal portland cement. Hammond low-heat-duty clay A clay that fuses between 1,520 degrees C and 1,590 degrees C. Osborne low-iron magnesite brick A burned magnesite brick, containing 90% or more of magnesia, and 1.5% to 2.5% iron oxide. low level Scot. The drift or working that is farthest to the dip; also called laigh level. low-nitrate barren In uranium leach treatment, the bulk of the barren solution after some 75,700 L of highnitrate solution have been run through the ion-exchange (IX) column. Low in nitrate and uranium and contains some backwash water. Pryor, 3 low powders Explosives containing a small portion of nitroglycerin and a base similar to blasting powder. Intermediate between blasting powder and dynamite in action. See: low-grade low-pressure air stower The filling of the waste by means of compressed-air blower. The blower is usually located close to the stowing machine and operated at a pressure below 15 psi (103.4 kPa). For light duties, only one blower is required to operate one stowing machine. For heavier work, or very long lengths of pipeline, two blowers are used in series. The 1853

maximum horsepower for two blowers in series does not commonly exceed 200 (149 kW) at large installations. See also: pneumatic stowing low-pressure limit The lowest pressure at which flame propagation can be obtained through a combustibleoxidant system at a fixed temperature in a particular chamber. Van Dolah low quartz Low-temperature quartz; when formed below 573 degrees C, SiO2 tetrahedra are less symmetrically arranged than at higher temperatures; inversion is reversible. Syn: alpha quartz low-rank coals See: rank low-rank metamorphism Metamorphism that is accomplished under conditions of low to moderate temperature and pressure. CF: high-rank metamorphism low red-heat Temperature of iron at which redness is observable in subdued daylight (525 to 700 degrees C). Bright red heat is in the range 700 to 1,000 degrees C and is followed by orange at 1,000 degrees C, white at 1,300 degrees C, and blue-white at 1,500+ degrees C. Pryor, 3 low shaft furnace A short shaft-type blast furnace that can be used to produce pig iron and ferroalloys from low-grade ores, using low-grade fuel. The air blast is often enriched with oxygen. It can also be used for making a variety of other products such as alumina, cement-making slags, and ammonia synthesis gas. ASM, 1 low-temperature carbonization Carbonization carried out at a low temperature (between 500 degrees C and 700 degrees C). During the process, the smoke-producing compounds are driven off as tars and oils and collected as valuable byproducts, leaving a coke with about 10% volatile matter. The coke yield is about 1,400 lb/st (700 kg/t) and is used as a domestic fuel. Nelson low-temperature coke 1854

A solid fuel produced by the low-temperature carbonization of coal. Nelson low-temperature incineration method In this method for the determination of incombustible matter, the mine roadway dust (dust containing carbonates) is incinerated at a temperature of not less than 500 degrees C and not more than 530 degrees C until it is constant in weight. This temperature is sufficient to complete the combustion of the organic matter in the dust, but is not high enough to decompose the carbonates. However, this method is unsuitable for dust containing magnesium carbonate because this substance decomposes below 500 degrees C, and therefore a low result for the incombustible matter would be obtained. The moisture content of the sample may be calculated so that an allowance can be made for the weight loss attributed to moisture. Cooper low-tension detonator A detonator requiring a minimum current of 1 A for firing and having a resistance of about 1 Omega . BS, 12 low-terrace drift Aust. Gravel and shingle in terraces. low velocity See: velocity low-velocity-layer correction See: weathering correction low volatile bituminous coal The rank of coal, within the bituminous class of Classification D 388, such that, on the dry and mineral-matter-free basis, the volatile matter content of the coal is greater than 14% but equal to or less than 22% (or the fixed carbon content is equal to or greater than 78% but less than 86%), and the coal commonly agglomerates. CF: bituminous coal ASTM low voltage In coal mining, 660 V or less. Also called low potential. CF: high voltage; medium voltage. Federal Mine Safety low working voltage 1855

Low working voltage in coal mines is one of the many conditions that must be given continual attention. Loss of voltage means a proportional loss in power. Since the quantity of dc power is obtained by multiplying the number of amperes times the number of volts, it follows that for a given amount of power if the volts are lowered the amperes are increased, and the increase in amperes results in an increase in power loss in the mine circuit. Lower operating voltages result in heavier currents in the dc motor circuits, thus heating the motors, cables, and circuit wiring and causing loss in motor speed, inefficient operation, and increased maintenance cost. Kentucky lozenge A form of cut stone produced by the meeting of the skill and star facets on the benzil of brilliants; or by the meeting of the facets in the horizontal ribs of the crown. Hess lpb To determine the horizontal compass direction that a borehole is trending at a specific depth by means of one of several borehole surveying instruments. Long LP delays Long period delays used in delay blasting underground and generally available in intervals of seconds. lublinite A fibrous variety of calcite. lubrication The act of applying lubricants. There are two main types of lubricants, solid and liquid. Examples of the solid type are graphite, French chalk, and sulfur. Liquid lubricants are by far the more important, and among these, oils and greases are the most common. Crispin; Morris Luce and Rozan process A modification of the Pattinson process whereby the molten lead is stirred by the injection of steam; used in desilverizing base bullion. Fay lucianite An expansive clay of the smectite(?) group at Santa Lucia, near Mexico, D.F. lucid attrite 1856

Variety of attritus that is transparent in thin section. Tomkeieff lucinite A variety of variscite from Lucin, UT. Luckiesh-Moss visibility meter This instrument has been used over a wide range of lighting applications. It consists of a pair of similar photographic gradient filters, which increase in density as they are rotated together before the eyes. The filters therefore reduce the apparent brightness of the observed field and at the same time lower the contrast between the object of view and its background. Roberts, 2 luckite A manganoan variety of melanterite at the Lucky Boy Mine, Salt Lake County, UT. lucky stone See: staurolite Lueders line Surface markings that result from strain. Sometimes called Hartmann lines; Piobert lines; stretcher strains. See also: slip line ludlamite A monoclinic mineral, (Fe,Mg,Mn)3 (PO4 )2 .4H2 O ; green; in small tabular crystals at Truro, Cornwall, U.K. Syn: lehrnerite ludwigite An orthorhombic mineral, Mg2 FeBO5 ; forms a series with vosenite; forms finely fibrous masses. Includes magnesioludwigite, ferroludwigite. Syn: collbranite lue Prov. Eng. To sift; a miner's term. Standard, 2 lueneburgite Alternate spelling of lueneburgite. 1857

lueshite A monoclinic mineral, NaNbO3 ; perovskite group; pseudocubic; dimorphous with natroniobite. Syn: igdloite luffing cableway mast A cableway tower hinged at the base and sustained by adjustable guys so that its inclination can be varied. Hammond lug a. A replaceable cutting member on an expansion reamer. Long b. One of a set of cutting lugs used to cut off a length of casing in a borehole at any desired point below the collar of the hole. Syn: jaw lug down To slow down an engine by increasing its load beyond its capacity. Nichols, 1 lugeon test Single-hole in situ test of formation permeability performed by measuring the volume of water taken in a section of test hole when the interval is pressurized at 10 bars (150 psi). Used primarily in variably permeable formations under evaluation for grouting. Houlsby Luhrig vanner Vanning machine with side feed and end shake--a hybrid between the true vanner and the shaking table. Pryor, 3 lumachelle a. A compact, dark-gray or dark-brown limestone or marble, composed chiefly of fossil mollusk shells, and characterized by a brilliant iridescence or chatoyant reflection from within. Syn: fire marble AGI b. Any accumulation of shells (esp. oysters) in stratified rocks. Etymol: French, coquina, oyster bed, from Italian lumachella, little snail. AGI lumber Timber that has been sawed into boards, planks, staves, or other pieces of comparatively small dimensions. In mines, timber is used in the construction of coal chutes, mine cars, mine doors, forms for concrete structures, surface buildings, and for many other purposes. Jones, 2 1858

lumber scale A graduated measuring scale for determining the number of board feet in rough-sawed lumber. Crispin luminance A measure of surface brightness that is expressed as luminous flux per unit solid angle per unit projected area. ASM, 1 luminance of a surface Luminous intensity per unit of apparent area; i.e., the area as projected on a plane normal to the direction of viewing. It is determined by the incident light flux falling upon the surface, the reflection factor of the surface, and the angle that the surface makes with the direction in which it is viewed. It is independent of distance; i.e., a surface appears equally bright no matter what the distance from which it is seen. Roberts, 2 luminescence a. The emission of light by a substance that has received energy or electromagnetic radiation of a different wavelength from an external stimulus; also, the light so produced. It occurs at temperatures lower than those required for incandescence. See also: phosphorescence; fluorescence. AGI b. Quantized electromagnetic emissions resulting from electrons in a crystal structure dropping from a higher excited state to a lower one. CF: thermoluminescence; triboluminescence. luminosity a. The quality of emitting or of giving out light; shining. Crispin b. Subjective brightness sensation. Roberts, 2 luminous Radiating or emitting light; bright; clear. Crispin Lumnite Well-known brand of quicksetting cement for sealing rock cavities, plugging drill holes, etc. Is made from bauxite ore and limestone and is highly resistant to acids and heat. Cumming, 1; Hess lump coal

1859

Bituminous coal in the large lumps remaining after a single screening that is often designated by the size of the mesh over which it passes and by which the minimum size lump is determined. Also, the largest marketable size. Webster 3rd; Fay Lump Coal Trademark for permissible dynamites (types C and CC) with very low velocity of detonation. Are used in coal mining where maximum production of large-size coal is desired. CCD, 2 lump ore See: natural ore lumpy Describes a gemstone cut with too great a depth in proportion to its width. lunar crater See: crater lunker Scot. A lenticular mass of sandstone or clay ironstone; a big nodule. CF: lonkey Lurgi process This process consists of roasting iron ore in a reducing atmosphere, thus forming magnetic oxide of iron that is separated by crushing followed by magnetic separation. The internal structure of the kiln is so designed that the ore falls in a continuous veil through the current of reducing gases. Burners are distributed throughout the periphery of the kiln, so that roasting and reduction can be controlled in the various zones to the required temperature. Blast furnace gas for reduction passes into the center of the lower end of the kiln, while the gas and air for heating pass in from the circumference of the drum, nearer to the center and upper end of the furnace. The ingoing ore is crushed to give a maximum size of 20 mm, while the outgoing concentrate is crushed to 3.8 mm after cooling. Osborne Lurmann front An arrangement of water-cooled castings through which iron and cinder are tapped from the blast furnace, thus avoiding the use of a forehearth. See also: dam lurry 1860

a. York. A weighted tram to which an endless rope is attached, fixed at the inby end of the plane, forming part of an appliance for taking up the slack rope. Fay b. A movable platform on wheels, the top of which is level with the bank or surface. It is run over the mouth of a shaft to receive the bucket when it reaches the top. A variation of lorry. Fay lusakite A cobaltoan variety of staurolite. lussatite A fibrous variety of silica, possibly tridymite. luster a. The character of the light reflected by minerals; it constitutes one of the means for distinguishing them. There are several kinds of luster: metallic, the luster of metals; adamantine, the luster of diamonds; vitreous, the luster of broken glass; resinous, the luster of yellow resin, as that of eleolite; pearlylike pearl; and silkylike silk. These lusters have different degrees of intensity, being either splendent, shining, glistening, or glimmering. When there is a total absence of luster, the mineral is characterized as being dull. Fay b. In ceramics, a glaze, varnish, or enamel applied to porcelain in a thin layer, and giving it a smooth, glistening surface. Standard, 2 luster mottling a. The macroscopic appearance of poikilitic rocks. AGI b. The shimmering appearance of a broken surface of a sandstone cemented with calcite, produced by the reflection of light from the cleavage faces of conspicuously large and independently oriented calcite crystals, 1 cm or more in diameter, incorporating colonies of detrital sand grains. It may also develop locally in barite, gypsum, or dolomite cements. AGI lutaceous Said of a sedimentary rock formed from mud (clay- and/or silt-size particles) or having the fine texture of impalpable powder or rock flour; pertaining to a lutite. Also said of the texture of such a rock. CF: argillaceous; pelitic. AGI lutecite A fibrous variety of chalcedony with fiber elongation perpendicular to the c crystallographic axis (opposite to normal chalcedony) and showing other optical anomalies. luthos lazuli 1861

A violet variety of fluorite. luting Sealing the joint of a retort with fire clay. Pryor, 3 lutite A general name used for consolidated rocks composed of silt and/or clay and of the associated materials which, when mixed with water, form mud; e.g., shale, mudstone, and calcilutite. The term is equivalent to the Greek-derived term "pelite." Etymol: Latin lutum, mud. Also spelled lutyte. See also: rudite; arenite. AGI lutose Covered with clay; miry. Webster 2nd luxullianite A granite characterized by phenocrysts of potassium feldspar and quartz that enclose clusters of radially arranged acicular tourmaline crystals in a groundmass of quartz, tourmaline, alkali feldspar, brown mica, and cassiterite. Its name is derived from Luxulyan, Cornwall. Also spelled: luxulianite; luxulyanite. Var: luxuliane. AGI luzonite A tetragonal mineral, Cu3 AsS4 ; stannite group; dimorphous with enargite. Formerly considered an arsenian variety of famatinite. lyddite High explosive based on picric acid, (NO2 )3 C6 H2 OH , with 10% nitrobenzene and 3% vaseline. Pryor, 3 Lydian stone A touchstone consisting of a compact, extremely fine-grained, velvet- or gray-black variety of jasper. Etymol: Greek Lydia, ancient country in Asia Minor. Syn: lydite; touchstone; basanite. AGI lydite See: Lydian stone lye 1862

See: double parting lying money An allowance to miners on piecework who are rendered idle during a shift owing to circumstances beyond their control, such as a breakdown in power services, or supplies of empty cars. Nelson lying wall See: footwall lynx eye Green iridescent labradorite. lynx sapphire a. Dark blue iolite variety of cordierite. b. Dark blue sapphires in Sri Lanka. lyophilic a. Condition of solid-liquid mixture in which surface-active molecules that contain two or more groups have both an affinity for the phase in which one group is dissolved, and a repulsion from this phase for another group or ion. See also: hydrophilic b. Having the property of attracting liquids. Pryor, 4 lyophobic Of, relating to, or having a lack of strong affinity between a dispersed phase and the liquid in which it is dispersed; systems such as colloidal metals in water are easily coagulated. Opposite of lyophilic. Webster 3rd lyosorption Adsorption of liquid to a solid surface. Pryor, 3 lype Scot. An irregularity in the mine roof. A projecting rock in a mine roof that may fall at any time. Usually used in the plural, and sometimes spelled lipe. Fay Lyster process

1863

A flotation process that separates galena and zinc blende by treatment, at a low temperature, with eucalyptus oil or other frothing agent, and with agitation or aeration in a neutral or alkaline, but not acid, solution of the sulfates, chlorides, or nitrates of calcium, magnesium, sodium, potassium, or mixtures of these substances. Fay lyway This term is commonly used in and around mines in Indiana and Illinois to describe a mine sidetrack or a passing track. Hess

M maacle See: macle macadam Crushed stone of regular sizes below 3 in (7.6 cm) for road construction, commonly with tar or asphalt binder. The sizes below 1 in (2.54 cm) are more specif. defined as chippings. See also: penetration macadam; tarmacadam. Nelson MacArthur and Forest cyanide process A process for recovering gold by leaching the pulped gold ore with a solution of 0.2% to 0.8% potassium cyanide, KCN, and then with water. The gold is obtained from this solution by precipitation on zinc or aluminum, or by electrolysis. See also: Elsner's equation macedonite a. A tetragonal mineral, PbTiO3 ; black; in irregular grains in quartz-syenite veins near Prilep, Macedonia. b. A bluish-black aphanitic igneous rock composed of alkali feldspars and biopyriboles; related to mugearite, a trachyandesite, Macedon district, Victoria, Australia. The name is not part of the IUGS classification of extrusive igneous rocks. maceral Applied to all petrologic units seen in microscopic sections of coal, as distinct from the visible units seen in the hand specimens. Comparable in rank to mineral as used in petrography. Thus, macerals are organic units composing the coal mass, being the 1864

descriptive equivalent of the inorganic units composing rock masses and universally called minerals. Individual macerals have the termination -inite; i.e., vitrinite, as the organic unit making up the lithologic specimen, vitrain. Three groups are recognized: (1) vitrinites; (2) exinites; and (3) inertinites. AGI macfarlanite A silver ore consisting of a mixture of sulfides, arsenides, etc., and containing cobalt, nickel, and lead. CF: animikite macgovernite See: mcgovernite machine boss In bituminous coal mining, a foreperson who is in charge of machine workers who undercut the working face of coal prior to blasting, and machine loaders who load the coal into cars after it is blasted down. DOT machine cut A slot or groove made horizontally or vertically in a coal seam by a coal cutter, as a preliminary step to shot firing. See also: cutting horizon Nelson machine-cutter helper See: machine helper machined a. A smooth surface finish on metal. Nichols, 1 b. Shaped by cutting or grinding. Nichols, 1 machine design The application of scientific principles to the practical constructive art of engineering, with the object of expressing original ideas in the form of drawings. See also: theory of machines machine driller In mining, one who operates any one of several types of heavy, mounted or unmounted, compressed-air drilling machines to drill holes into the working face of ore or rock into 1865

which explosives are inserted and set off to blast down the mass. Also called drill engineer; drillman; drill operator; power driller. DOT machine helper In anthracite and bituminous coal mining, one who assists the machineman in moving and setting up the coal-cutting machine in position for cutting a channel under or along the sides of the coal working face prior to breaking the coal down with explosives. Also called chain-machine helper; coal-cutter helper; cutter helper; cutting-machineman helper; jack setter; machine-cutter helper; machineman helper; miner; assistant; miningmachine-operator helper. DOT machine holings The small coal or dirt produced by a coal cutter. Nelson machine loader a. In anthracite and bituminous coal mining, person who operates an electric loading machine that digs, elevates, and loads coal blasted from the working face into cars by means of a conveyor loaded by a scraping device, a digging conveyor, or a shoveling mechanism. May be designated according to machine used, as Joy loader. Also called loader engineer; loader operator; loader runner; loading-machine man; loading-machine operator; loading-machine runner. DOT b. Machine loader I is used in anthracite coal mining, bituminous coal mining, and metal mining, to designate one who operates a small electric or air-power shovel in underground working places to load ore or rock into cars after it has been blasted from the working face. Also called loader operator; loadingmachine operator; mechanical-shovel operator; shovel operator. DOT c. Machine loader II is used in anthracite coal mining, bituminous coal mining, and metal mining, to designate one who operates a loading machine consisting of a small hoisting engine and a cable-drawn scraper, or scoop, to load ore or rock into cars after it has been blasted from the working face in underground or open-pit mines. Also called scraper-loader hoistman; scraper-loader operator; scraper operator. DOT machine loader helper In anthracite coal mining and bituminous coal mining, a laborer who assists a machine loader in loading coal into cars. DOT machineman a. A coal-cutter operator. See also: coal-cutter team b. A person who sets up and operates an electrically driven or compressed-air-driven coal-cutting machine that is used to cut out a channel along the bottom or side of the working face of coal so that it may be blasted down without shattering the mass. Also called coal cutter; coal-cutting machine 1866

operator; machine cutter; cutter operator; cutting machine operator; holer; undercutter. DOT c. Eng. One who weighs coal, etc., and keeps an account of the number of cars sent to the surface. Fay machineman helper See: machine helper machine miner In bituminous coal mining, a general term applied to workers who are capable of operating one or more coal mining machines used for drilling, loading, and undercutting. Usually designated as machine driller; machine loader I; machine loader II; machineman. Also called machine operator; machine runner; mining machine operator. DOT machine mines Mines in which coal is cut by machines. Kiser machine mining a. Implies the use of power machines and equipment in the excavation and extraction of coal or ore. In coal mines, the term almost invariably signifies the use of coal cutters and conveyors and perhaps some type of power loader working in conjunction with face conveyors. See also: face mechanization b. Mechanized mining. CTD machine nog Eng. A wedge-shaped wood block for supporting machine-cut coal. SMRB machine operator See: machine miner machine rating a. The amount of power a machine can deliver without overheating. Crispin b. Also, work capacity of a machine. machine runner See: machine miner machine screw 1867

A very commonly used type of screw with clear-cut threads and of a variety of head shapes. It may be used either with or without a nut. Crispin machine set See: mechanical set machine sumper See: sumper machine tool Any machine used for cutting metal, such as a boring machine, drill, grinder, planing machine, hobber, shaper, or lathe. Hammond machine wall The face at which a coal-cutting machine works. Fay machinist Aust. The person in charge of a coal cutter. Fay mackintoshite See: thorogummite Mac-Lane system This system consists essentially of an inclined rail track with the haulage gear and the loading station at the base. The haulage rope passes round a return sheave in the extending frame at the top of the heap. The tipping gear may consist of a carriage with a portable tippler that conveys a tub of dirt to the top of the heap, where a trigger operates the tippler, thus discharging the tub. For a greater quantity, the carriage incorporates a revolving frame carrying two or three tubs; this gives a broader top to the heap. The main disadvantages of this system are the unsightly conical heaps produced and the tendency to segregation of material, with the large pieces at the base of the heap, which increases the danger of spontaneous combustion. Sinclair, 5 macle a. A twin crystal; esp. octahedral diamond twins flattened parallel to the twin plane. Also spelled maacle, maccle, mackle. b. A variety of andalusite with tessellated cross section resulting from segregation of carbonaceous impurities. Syn: chiastolite 1868

Maclean separator A revolving disk-type magnetic separator widely used for the separation of large quantities of ilmenite from tin ore. Harrison macled a. Twinned. b. See: tessellated c. Spotted. Also spelled mackled. macroA prefix meaning large, long; visibly large, e.g., macrocrystalline. CF: micromacro-axis In the orthorhombic and triclinic systems, an obsolete term for the longer lateral crystallographic axis, the b axis in orthorhombic and mostly the b axis in triclinic minerals. macrocrystalline Said of the texture of a rock consisting of or having crystals that are large enough to be distinctly visible to the unaided eye or with the use of a simple lens; also, said of a rock with such a texture. Syn: eucrystalline macrodiagonal In crystallography, the longer lateral axis in the orthorhombic and triclinic systems. Standard, 2 macrodome a. In crystallography, a dome parallel to the macrodiagonal. CF: dome Standard, 2 b. In the orthorhombic system, an obsolete term for a form of four faces parallel to the macroaxis, but intercepting the other two. Syn: horizontal prism c. In the triclinic system, an obsolete term for a form of two faces parallel to the macro-axis, but intercepting the other two. macroetch Etching of a metal surface for accentuation of gross structural details and defects for observation by the unaided eye or at magnifications not exceeding 10 diameters. ASM, 1 macrograph 1869

A graphic reproduction of the surface of a prepared specimen at a magnification not exceeding 10 diameters. When photographed, the reproduction is known as a photomacrograph. ASM, 1 macromeritic See: phaneritic macroporosity Porosity visible without the aid of a microscope, such as pipes and blowholes in ingots. Newton, 1 macroscopic a. Visible at magnifications of from 1 to 10 diameters. ASM, 1 b. Visible without a microscope or in a hand specimen. See also: megascopic macrostructure a. The general arrangement of crystals in a solid metal (for example, an ingot) as seen by the naked eye or at low magnification. The term is also applied to the general distribution of impurities in a mass of metal as seen by the naked eye after certain methods of etching. CTD b. The structure of metals as revealed by examination of the etched surface of a polished specimen at a magnification not exceeding 10 diameters. ASM, 1 c. A structural feature of a rock that is discernible to the unaided eye, or with the help of a simple magnifier. Fay d. The arrangement of crystals in a metal or in a rock that, with or without etching or other chemical treatment, is discernible to the unaided eye or with the help of a simple magnifier (generally less than 10X). maculose Applied to the group of contact-metamorphic rocks represented by spotted slates, to denote its spotted or knotted character. The term may be applied either to the rock or to its structures. See also: spotted slate maculose rock See: spotted slate Madagascar aquamarine A strongly dichroic variety of blue beryl obtained, as a gemstone material, from Malagasy Republic. CTD 1870

Madaras system A method of obtaining pig iron, consisting of charging a retort with a mixture of iron ore, coal, and enough water to form a paste; and injecting compressed air at 2 to 4.2 kg/cm2 pressure and at 815 to 930 degrees C to burn the coal. In a few minutes the entire mineral charge is heated to 980 to 1,095 degrees C, which is the optimum range for hydrogen reduction; then hydrogen is injected at a temperature of 815 to 923 degrees C at 2 to 8 kg/cm2 pressure so that it penetrates the entire mass and reacts with the iron oxide to produce steam and metallic iron. About 50% of the injected hydrogen reacts with the ore to produce sponge iron. Sulfur is oxidized by the hot air and is eliminated by the hydrogen. Osborne made ground a. A recent deposit, as of river silt. Fay b. Ground formed by filling in natural or artificial pits with hardcore or rubbish. CTD Madeira topaz Citrine variety of quartz. CF: false topaz; Spanish topaz. made up Coupled; the assembled component parts of a drill string or pipe system. Long madogram A plot of mean absolute difference of paired sample measurements as a function of distance and direction. Madograms are not true variograms, and generally should not be used in kriging. If used, the kriged estimates might be "reasonable," but the kriging standard deviations will be meaningless. madrepore marble A fossiliferous limestone occurring in a variety of colors. It takes a high polish, is used as a marble, and derives its name from its most characteristic fossil, a species of coral. maenite An intrusive trachytic rock, regarded as a differentiation product of a gabbroic magma. Maenite is a bostonite relatively high in calcium and low in potassium. mafelsic

1871

Said of igneous rocks containing roughly equal amounts of felsic and mafic minerals, color index 40 to 70. AGI mafic Pertaining to or composed dominantly of the ferromagnesian rock-forming silicates; said of some igneous rocks and their constituent minerals. CF: basic; felsic. See also: mafite mafic front See: basic front mafite Any dark mineral in Johannsen's classification of igneous rocks. See also: mafic magazine a. A storage place for explosives. Jones, 1 b. A building specially constructed and located for the storage of explosives. CF: powder chest maghemite An isometric mineral, gamma-Fe2 O3 ; magnetite series; spinel group; dimorphous with hematite; strongly ferrimagnetic. Syn: oxymagnite magistral Roasted copper pyrites. Pryor, 3 magma Naturally occurring molten rock, generated within the Earth and capable of intrusion and extrusion, from which igneous rocks are derived through solidification and related processes. It may or may not contain suspended solids (such as crystals and rock fragments) and/or gas phases. Adj: magmatic. AGI magmatic Of, pertaining to, or derived from magma. See also: igneous magmatic assimilation See: assimilation 1872

magmatic blister The swelling up by differential heating of magma; e.g., by local concentrations of radioactive matter. Schieferdecker magmatic corrosion A process of re-solution in which an early formed phase, such a quartz phenocryst, later becomes corroded or embayed as the result of some change in the conditions affecting the solubility of the phase; sometimes corrosion rims result. Syn: corrosion magmatic cycle See: igneous cycle magmatic deposit See: magmatic ore deposit magmatic differentiation The process by which more than one rock type is derived from a parent magma. CF: assimilation magmatic disseminated ore deposit See: disseminated deposit magmatic dissolution See: assimilation magmatic injection deposit Straight magmatic mineral (ore) deposit, the formation of which has often been ascribed to injection into the older country rock of liquefied crystal differentiates, of residual liquid segregations, or of immiscible liquid separations and accumulations. An older term. Schieferdecker magmatic ore deposit An ore deposit formed by magmatic segregation, generally in mafic rocks and layered intrusions, as crystals of metallic oxides or from an immiscible sulfide liquid. Syn: magmatic deposit 1873

magmatic segregation Concentration of crystals of a particular mineral (or minerals) in certain parts of a magma during its cooling and crystallization. Some ore deposits (i.e., magmatic ore deposits) are formed in this way. See also: differentiation magmatic stoping A process of magmatic emplacement or intrusion that involves detaching and engulfing pieces of the country rock. The engulfed material presumably sinks downward and/or is assimilated. See also: piecemeal stoping AGI magmatic water Water contained in or expelled from magma. CF: juvenile water AGI magmatist One who believes that much granite is a primary igneous rock produced by differentiation from basaltic magma. CF: transformist Magnafloat Trademark for iron oxide heavy media systems for the purification of coal, sand, gravel, and other similar materials. CCD, 2 Magnedisc A widely used medium for magnetic recording. It consists of a circular platter of magnetically coated plastic material that rotates on a turntable in the same way as a phonograph record. The magnetic channels, each in contact with a fixed head aligned along a radius from the center, are on concentric circular bands extending inward from the outer edge of the disk. Dobrin magnesia Magnesium oxide, MgO. A constituent of lime made from dolomitic limestone. Barger; AGI; Mersereau, 2 magnesia alum See: pickeringite magnesia covering 1874

Hydrated magnesium carbonate containing about 15% asbestos, used for heat insulation. Also referred to as 85% magnesia. Osborne magnesia glass Glass containing usually 3% to 4% of magnesium oxide. Electric lamp bulbs have been mainly made from this type of glass since fully automatic methods of production were adopted. CTD magnesia mica See: biotite magnesian hornfels A fine-grained metamorphic rock derived from a high-magnesium igneous rock; e.g., serpentine. See also: hornfels magnesian limestone A limestone containing from 5% to 35% MgCO3 . CF: dolomitic limestone magnesian marble A crystalline variety of limestone containing not less than 5% nor more than 40% of magnesium carbonate as the dolomite constituent. magnesian schist A schistose metamorphic rock derived from a rock high in content of magnesium; e.g., serpentine. See also: schist magnesian spar See: dolomite magnesia ramming materials Granular, airsetting mixtures, containing 70% to 80% MgO, used for monolithic furnace linings. magnesiochromite

1875

An isometric mineral, MgCr2 O4 ; chromite series; spinel group; forms series with spinel and with chromite; crystallizes in black octahedra, but commonly massive. Also spelled magnochromite. Syn: picrochromite magnesioferrite An isometric mineral, MgFe2 O4 ; magnetite series; spinel group; strongly ferrimagnetic. Also spelled magnoferrite. magnesiolaumontite A magnesian variety of laumontite. magnesite A trigonal mineral, MgCO3 ; calcite group; rhombohedral cleavage; in veins in serpentinite and peridotite, magnesium-rich schist, and altered dolomitic marbles. Syn: giobertite; magnesium carbonate. magnesite cement Common term for ground magnesite. magnesite refractory A refractory material, fired or chemically bonded, consisting essentially of dead-burned magnesite; the MgO content usually exceeds 80%. Such refractories are used in the hearths and walls of basic steel furnaces, mixer furnaces, and cement kilns. Dodd magnesium A light, silvery-white, and fairly tough metal. Symbol, Mg. It does not occur uncombined, is found in large deposits in the form of magnesite, dolomite, and other minerals. Readily ignites upon heating. Used in flashlight photography, flares, and pyrotechnics, including incendiary bombs. Its alloys are essential for airplane and missile construction. Handbook of Chemistry and Physics, 3 magnesium aluminate MgAl2 O4 ; melting point, 2,135 degrees C; sp gr, 3.6; thermal expansion (100 to 1,000 degrees C), 9.0 X 10-6 . This compound is the type mineral of the spinel group. See also: spinel Dodd magnesium-aluminum garnet 1876

See: pyrope magnesium bentonite A smectite with exchangeable magnesium. magnesium blodite See: bloedite magnesium carbonate See: magnesite magnesium chalcanthite See: pentahydrite magnesium-chlorophoenicite A monoclinic mineral, (Mg,Mn)3 Zn2 (AsO4 )(OH,O)6 ; associated with manganese silicates at Franklin, NJ. magnesium front See: basic front magnesium kaolinite See: amesite magnesium leonite See: leonite magnesium mica See: phlogopite magnesium minerals Chiefly magnesite, dolomite, and brucite. magnesium orthite 1877

A magnesian variety of allanite. magnesium titanate MgTiO3 . Used in ceramic dielectric bodies. Although relatively low in dielectric constant, it has a positive temperature coefficient of capacity. Thus, it can be used in conjunction with a negative coefficient material; e.g., titania, to produce a near 0 temperature coefficient product. Lee magnesium zirconate MgZrO; melting point, 2,150 degrees C. This compound is sometimes added in small amounts (up to 5%) to other electroceramic bodies to lower their dielectric constant at the Curie point. Dodd magnetic Of or pertaining to a mineral, object, area, or locale possessing the properties of a magnet. Long magnetic alloys Alnico is an alloy of aluminum, nickel, and cobalt, with strong magnetic properties similar in all directions. Alcomax is anisotropic, with maximum flux along preferred axis. Hycomax is also anisotropic. Platinax, a cobalt-platinum alloy containing 23.3% cobalt, is isotropic. Pryor, 3 magnetic anomaly Variation of the measured magnetic pattern from a theoretical or empirically smoothed magnetic field. Hy magnetic azimuth The azimuth measured clockwise from magnetic north through 360 degrees ; the angle at the point of observation between the vertical plane through the observed object and the vertical plane in which a freely suspended magnetized needle, influenced by no transient artificial magnetic disturbance, will come to rest. AGI magnetic bearing The bearing expressed as a horizontal angle between the local magnetic meridian and a line on the Earth; a bearing measured clockwise from magnetic north. It differs from a true bearing by the amount of magnetic declination at the point of observation. AGI 1878

magnetic bort See: bort magnetic bottle A magnetic field used to confine a plasma in controlled-fusion experiments. Lyman magnetic circuit The closed path taken by the magnetic flux in an electric machine or other piece of apparatus. CTD magnetic clutch One in which connection between drive and driven member is provided by electromagnetic force. Pryor, 3 magnetic correlation The orientation of an underground survey, using the Earth's magnetic field. BS, 7 magnetic crack detection The part to be examined is magnetized either by passing a heavy current through it or by making it the core of a coil through which a heavy current is passed. Small cracks, or nonmagnetic phases such as inclusions, cause the magnetic flux to break the surface, thus forming small magnets. When the part is sprayed with a suspension of iron oxide particles in paraffin, the particles cling to the small magnets and thereby reveal defects. Hammond magnetic declination In nautical and aeronautical navigation, the continually changing acute angle between the direction of the magnetic and geographic meridians. The term "magnetic variation" is preferred. AGI magnetic detector An electrical device for indicating the presence of magnetic material in an area. magnetic dip Vertical angle through which a freely suspended magnetic needle dips from horizontal. Pryor, 3 1879

magnetic domain Aggregation of ferromagnetic atoms into a group, usually a fraction of a micrometer in size, which lies among similar groups with random group orientation. This cancels out any magnetic moment until or unless they all are oriented by an applied magnetic field. Pryor, 3 magnetic elements a. These are declination, dip, and magnetic intensity in the horizontal plane. Pryor, 3 b. The characteristics of a magnetic field that can be expressed numerically. The seven magnetic elements are declination D, inclination I, total intensity F, horizontal intensity H, vertical intensity Z, north component X, east component Y. Typically, only three elements are needed to give a complete vector specification of the magnetic field. AGI magnetic feeder Any feeder that uses magnetism to pick up, hold, separate, and deliver objects. magnetic field a. Space surrounding a magnet or current-carrying coil, in which appreciable magnetic force exists. Its intensity (H) is the force exerted on a unit pole. Pryor, 3 b. A region in which magnetic forces would be exerted on any magnetized bodies or electric currents present; the region of influence of a magnetized body or an electric current. AGI magnetic field strength The force exerted on a unit pole is the field strength at that point. AGI magnetic flocculation Phenomenon that results from residual magnetism of ferromagnetic particles that have bunched together under the influence of their individual polar forces. Pryor, 3 magnetic flowmeter A device used for the flow measurement of abrasive slurries. The calibration is affected by the presence of magnetic constituents in the slurry, and therefore, a pipe coil is also used to compensate the magnetic flowmeter calibration for varying amounts of magnetic material in the slurry. Nelson magnetic flux

1880

a. Induced strength or flux density in a magnetic field, measured in maxwells: B = 4pi /A + H, where B = the flux density, P = the strength of each magnetic pole, A = the crosssectional area of a cylinder through which the flux flows, and H = the magnetic intensity in oersteds. See also: magnetic intensity b. The surface area times the normal component of magnetic induction B; the number of magnetic field lines crossing the surface of a given area. Expressed in maxwells in the cgs system. AGI magnetic gradiometer An instrument, designed but not applied, for measuring the gradient of the magnetic intensity. AGI magnetic hoist A hoisting device that does its lifting by means of an electromagnet. Crispin magnetic hysteresis See: hysteresis magnetic induction a. Magnetic-flux density, symbolized by B. In a magnetic medium, it is the vector sum of the inducing field H and the magnetization M. B is expressed in teslas in SI and in gauss or gammas in the cgs system. Syn: magnetic field b. In a magnetic medium, the vector sum of the inducing field H and the corresponding intensity of magnetization I, according to the relationship B = H + 4pi I. AGI c. A nonrecommended syn. of electromagnetic induction. AGI d. The process of magnetizing a body by applying a magnetic field. This usage is not recommended. AGI magnetic intensity A vector quantity pertaining to the condition at any point under magnetic influence (as of a magnet, an electric current, or an electromagnetic wave) measured by the force exerted in a vacuum upon a free unit north pole placed at the point in question. Also called magnetic force. Webster 3rd magnetic iron ore See: magnetite magnetic level coil A device for measuring the liquid level in sumps and other vessels. It consists of a loop of wire that is encased in a fiber glass protective sheath. The loop is inserted in a sump of 1881

thickener containing a magnetite or ferrosilicon slurry, and the electrical signal given off represents the level of the slurry surrounding the loop. Nelson magnetic meridian The horizontal line that is oriented, at any specified point on the Earth's surface, along the direction of the horizontal component of the Earth's magnetic field at that point; not to be confused with isogonic line. Syn: geomagnetic meridian magnetic method A geophysical prospecting method that maps variations in the magnetic field of the Earth that are attributable to changes of structure or magnetic susceptibility in certain nearsurface rocks. Sedimentary rocks generally have a very small susceptibility compared with igneous or metamorphic rocks, and most magnetic surveys are designed to map structure on or within the basement, or to detect magnetic minerals directly. Most magnetic prospecting is now carried on with airborne instruments. Dobrin magnetic mirror A magnetic field used in controlled-fusion experiments to reflect charged particles back into the central region of a magnetic bottle. Lyman magnetic moment a. That vector associated with a magnetized mass; the vector product of it and the magnetic field intensity in which the mass is immersed (ignoring the field distortion thereby produced) is a measure of the resulting torque. Also called moment of a magnet. AGI b. A vector quantity characteristic of a magnetized body or an electric-current system; it is proportional to the magnetic-field intensity produced by this body and also to the force experienced in the magnetic field of another magnetized body or electric current. The magnetic moment per unit volume is the magnetization. AGI magnetic permeability Ratio of magnetic induction (B) to the inducing field of magnetic intensity (H). With magnetic intensity lines of force per square centimeter in air, and flux density lines in a substance placed in that field, B/H is the magnetic permeability. When this is less than 1.0, the substance is diamagnetic; above 1.0, paramagnetic; and when high, ferromagnetic. Pryor, 3 magnetic plug A drain or inspection plug magnetized for the purpose of attracting and holding iron or steel particles in a lubricant. Nichols, 1 1882

magnetic polarity The orientation of the constituent minerals within the rocks of the Earth's crust conforming to the Earth's magnetic field as it existed at the time the strata were deposited. See also: core orientation Long magnetic pole a. Either of two points on the Earth's surface where the lines of magnetic force are vertical; an end of the axis of the Earth's magnetic polarity, not coincident with a geographic pole, and continually changing its position. The north magnetic pole is in northern Canada. Standard, 2 b. Either of two nonstationary regions on the Earth that sometimes move many miles in a day, toward which the isogonic lines converge, and at which the dip is + or -90 degrees . Webster 3rd c. The area on a magnetized part at which the magnetic field leaves or enters the part. It is a point of maximum attraction in a magnet. ASM, 1 magnetic prospecting See: magnetic method magnetic pyrite See: pyrrhotite magnetic recording Any process by which the output of a detector-amplifier system is recorded on a magnetic recording medium. The advantages of such a system are that the resulting records may be played back and converted into conventional records with phase shifting, mixing, etc., between traces and with filtering variations. Most modern magnetic recording is in digital form. AGI magnetic roasting process Heating ferrous iron ore in the presence of air in order to oxidize the iron content, present in whatever form, to the magnetic oxide so that in a subsequent operation it can be separated from the gangue by means of a magnetic separator. Also, roasting a hematitic ore with scrap iron to reduce it to magnetite. Osborne magnetic roll feeder A feeder that uses magnetized, power-operated rolls for separating and delivering objects. 1883

magnetics Branch of science that deals with magnetic phenomena. Osborne magnetic separation a. The separation of magnetic materials from nonmagnetic materials, using a magnet. This is an esp. important process in the beneficiation of iron ores in which the magnetic mineral is separated from nonmagnetic material; e.g., magnetite from other minerals, roasted pyrite from sphalerite, etc. Newton, 1; Henderson b. The use of permanent magnets or electromagnets to remove relatively strongly ferromagnetic particles from paramagnetic and diamagnetic ores. Pryor, 2 magnetic separator a. A device used to separate magnetic from less magnetic or nonmagnetic materials. The crushed material is conveyed on a belt past a magnet. ASM, 1 b. For medium solids recovery. A device in which medium solids are caused to adhere, by magnetic means, to a conveying belt or drum, while a current of water removes nonmagnetic particles that contaminate the medium. BS, 5 magnetic storm A worldwide disturbance of the Earth's magnetic field, commonly with amplitude of 50 to 200 gammas. It generally lasts several days, and is thought to be caused by charged particles ejected by solar flares. Magnetic prospecting usually has to be suspended during such periods. AGI magnetic susceptibility A measure of the degree to which a substance is attracted to a magnet; the ratio of the intensity of magnetization to the magnetic field strength. See: susceptibility magnetic unit in prospecting The gamma (Gamma ), which equals 10-5 Oe (7.9577 X 10-4 A/m). AGI magnetic variation See: declination magnetic variometer

1884

A geophysical instrument similar to the gravimeter in that absolute values are not measured, but only the differences in vertical magnetic force between field stations and a selected base station. Nelson magnetism a. That property of iron, steel, and some other substances, by virtue of which they exert forces of attraction and repulsion according to fixed laws. Crispin b. The science that is concerned with the conditions and laws of magnetic force. Crispin magnetite a. An isometric mineral, 8[FeOFe2 O3 ] ; spinel group; forms series with jacobsite and with magnesioferrite; crystallizes in octahedra; metallic; black; strongly ferrimagnetic; an accessory mineral in many igneous rocks; a common detrital mineral; a major mineral in banded iron formations and magmatic iron deposits; an ore of iron. Syn: black iron ore; lodestone; magnetic iron ore; octahedral iron ore. See also: iron ore b. The mineral series magnesioferrite, magnetite, maghemite, franklinite, jacobsite, and trevorite in the spinel group. Syn: iron series magnetite An igneous rock consisting essentially of magnetite and having an iron content of 65% to 70% or more. Apatite may accompany the magnetite. Johannsen magnetite olivinite A dunite high in content of titaniferous magnetite and containing shreds of biotite. Holmes, 2 magnetite spinellite An eruptive iron ore occurring at Routivara, Sweden, and consisting of magnetite (in part titaniferous), spinel, and smaller amounts of olivine, pyroxene, apatite, and pyrrhotite. The ore contains about 14% titanic oxide. magnetized A body is said to be magnetized when it possesses or can be made to possess that peculiar property whereby, under certain circumstances, it will naturally attract or repel a similar body in accordance with magnetic laws; e.g., drill rods become magnetized in use and will strongly attract other iron or steel articles. Long magnetizing force 1885

a. The phenomenon associated with a magnetic flux density at a point. Theoretically, measured by the mechanical force on a unit magnetic pole in an evacuated tunnel along the direction of the magnetic flux; the magnetomotive force per centimeter in this direction. CTD b. A force field, resulting from the flow of electric currents or from magnetized bodies, that produces magnetic induction. ASM, 1 magnetizing roast A process in which an ore containing pyrite is heated and the magnetic iron oxide so formed is removed by a magnetic separator. In many cases the iron oxide is extracted as gangue. Nelson magnetometer a. An instrument for measuring magnetic intensity. In ground magnetic prospecting, an instrument for measuring the vertical magnetic intensity; in airborne magnetic prospecting, an instrument for measuring the total magnetic intensity. Also, an instrument used in magnetic observatories for measuring various components of the magnetic field of the Earth. AGI b. A sensitive instrument for detecting and measuring changes in the Earth's magnetic field, used in prospecting to detect magnetic anomalies and magnetic gradients in rock formations. See also: airborne magnetometer magnetoplumbite a. A hexagonal mineral, Pb(Fe,Mn)12 O19 ; black; ferrimagnetic; at Laangban, Sweden. b. The mineral group hawthorneite, hibonite, magnetoplumbite, and yimengite. magnetorque A form of transmission based on the principle that a magnetic field of force is produced whose strength is varied so as to transmit a torque of corresponding magnitude. With a system of this kind, control of any particular operation is effected through the agency of the magnetorque clutch, while the motor runs continuously at constant speed. Mining magnetostriction The characteristic of a material that is manifest by strain when it is subjected to a magnetic field; or the inverse. Some iron-nickel alloys expand; pure nickel contracts. ASM, 1 magnetotelluric method a. An electrical prospecting technique based on an application of telluric currents in which the magnetic fields induced by the alternations in earth currents would be measured simultaneously with the voltage fluctuations between electrodes at the surface. 1886

The ratio between the amplitudes of these alternating voltages and the associated magnetic fields would be plotted as a function of frequency. Dobrin b. An electromagnetic method of surveying, in which natural electric and magnetic fields are measured. Usually the two horizontal electric-field components plus the three magneticfield components are recorded; orthogonal pairs yield elements of the tensor impedance of the Earth. This impedance is measured at frequencies within the range 10-5 Hz to 10 Hz. AGI magniotriplite A monoclinic mineral, (Mg,Fe,Mn)2 (PO4 )F ; yellow. magnochromite A variety of chromite that contains magnesium. Alternate spelling of magnesiochromite. Standard, 2 magnocolumbite An orthorhombic mineral, (Mg,Fe,Mn)(Nb,Ta)2 O6 . CF: columbite magnoferrite Original form of magnesioferrite. Dana, 1 magnussonite An isometric and tetragonal mineral, Mn5 As3 O9 (OH,Cl) ; green; forms crusts at Laangban, Sweden, and green to brown selvages at Sterling Hill, NJ. mahogany ore Compact mixture of oxides of iron and copper. Schaller mailly stone A softer sort of limestone, very dusty. Arkell main airway a. The road along which the principal ventilating current passes. Peel b. Underground ventilation channel directly connected with a shaft or other entry to a mine. Pryor, 3 main-and-tail haulage 1887

A single-track haulage system operated by a haulage engine with two drums, each with a separate rope. The engine is usually located at the out end of the system. The main rope is attached to the out end of the set of tubs, and the tail rope passes around a sheave in, and is then attached to, the rear end of the set. To draw the full set out, the main rope is wound in, the tail rope being allowed to run free. To draw the empty set in, the tail rope is wound in, the main rope being allowed to run free. The tail rope is equal to twice the length of the haulage road. The main-and-tail haulage is adopted when the gradient is irregular and the empty set will not run in by gravity. See also: rope haulage main arch a. The refractory blocks forming the part of a horizontal gas retort comprising the division walls and the roof that covers the retorts and the recuperators. Dodd b. General term for the central part of a furnace roof, particularly used as a syn. for the crown of a glass tank furnace. Dodd main bord gate York. The heading that is driven slightly to the rise from the shaft. Fay main bottom Hard rock below alluvial deposits. main break In mine subsidence, the break that occurs over the seam at an angle from the vertical equal to half the dip. Lewis main brow Eng. See: gate main conveyor See: underground mine conveyor main crosscut The crosscut that traverses the entire mining field and penetrates all deposits. There is such a crosscut at each level, and it is the main one for the level in question. It serves the same purpose as the shaft and thus must have correct cross section, and be particularly well constructed, as repairs to its support would hold up the transport of the entire level. Stoces 1888

main drive A main tunnel driven in the rock underlying a lead and about 50 ft (15.2 m) below the wash dirt. It is used as a drainage tunnel for carrying the water from the drainage holes to the shaft sump and also for the transport of cars from the raises. Eng. Min. J., 1 main endings Pairs of narrow coal headings with crosscuts at intervals, driven to form large pillars of coal in panel working. See also: narrow work Nelson main engine N. of Eng. The surface pumping engine, usually of the Cornish type. Fay main entry a. The principal entry or set of entries driven through the mine from which cross entries, room entries, or rooms are turned. Federal Mine Safety b. A term used in the United States for the principal horizontal gallery giving access to an underground mine and used for haulage, ventilation, etc. Where two entries are driven in parallel, the term "double entry" is used. With three parallel entries, the term "triple entry" is used. Nelson c. An entry driven at right angles with the face slips of the coal. See also: entry d. A main haulage road. See also: main road Maine sampler A drive-type, split-tube soil-sampling device, usually equipped with a flap or clack valve near the cutting shoe. Usually produced in sizes having outside diameters ranging from 4 to 6-5/8 in (10 to 17 cm). Long Maine-type sampler A soil-sampling device that works essentially on the same principle as a Maine sampler. Long main facets a. The bezel and pavilion facets. b. Any facet extending from the girdle to the table or from the girdle to the cutlet. main fans Main fans produce the general ventilating current of the mine, and are generally of large capacity and permanently installed. They are assisted by natural ventilation, if present, 1889

and, if necessary, by booster fans. They are installed to perform a certain duty, and great attention is paid to their efficiency since this governs the cost of performing the duty. Roberts, 1 main firing The firing of a round of shots by means of current supplied by a transformer fed from a main power supply. BS, 12 main gate The principal or central heading along which the coal is conveyed from two or more conveyor panels. Normally, the main gate is also the intake airway to the face. See also: double-unit conveyor; bottom gate; mother gate. Nelson main haulage a. That portion of the haulage system that moves the coal from the secondary haulage system to the shaft or mine opening. The method employed is the same for either longwall or room-and-pillar mining. Any one of four methods may be used: (1) mine cars and battery or trolley locomotives, (2) mine cars and a direct rope haulage, (3) a combination of methods 1 and 2, or (4) belt conveyors. Wheeler, R.R. b. The system by which coal is transported in trains in or out of a slope or drift entry or from the bottom of a shaft. BCI main haulage conveyor Generally 500 to 3,000 ft (approx. 150 to 1,000 m) in length. It is used to transport material between the intermediate haulage conveyor and a car-loading point or the outside. NEMA, 2 main haulageway The principal transportation road, drift, tunnel, etc. BCI main hole The first or primary borehole from which secondary or branch holes are drilled. Also called original hole; parent hole. CF: branch Long main intake The trunk or principal intake airway of a mine. The main intake air current is usually split into two or more air currents before reaching the workings. Nelson 1890

main levels The first and leading excavations in mines that are made for the purpose of opening out or winning the material being mined, and that are intended to be the principal roadways of the mine. Peel main-line locomotive A large, high-powered locomotive that hauls trains of cars over the main haulage system. BCI main-line motorman In bituminous coal mining, a person who operates a mine locomotive to haul cars over the main haulage tracks underground or at the surface, as distinguished from the branch lines. DOT main return The principal return airway of a mine. The main return air current represents the total quantity of air; i.e., after the air splits have reunited. Nelson main road The principal underground road in a district along which mined material is conveyed to the shafts, generally forming the main intake air course of each district. See also: main entry main rod Corn. See: pump rod main roof The rock above the immediate roof. Obert main rope The rope that pulls a train of loaded cars out along a haulage plane, as opposed to a tail rope that pulls a train of empty cars in, as in main-and-tail haulage. See also: pull rope main-rope haulage system This system of haulage is used for hauling loaded trains of tubs or cars up, or lowering them down, a comparatively steep gradient that is not steep enough, in the latter case, for 1891

a self-acting incline. In the normal system, a single track only is required. The electrically driven or compressed-air-driven engine has a single drum that runs loose on the forged-steel drum shaft; it is controlled by the brake when lowering the empty train, and is clutched to the shaft by means of a dog clutch when hauling the loaded train up the gradient. Sinclair, 5 main-rope rider In bituminous coal mining, one who has charge of and rides trips (trains) of cars hauled in and out of the mine along the main cable haulageway. DOT main-rope system A system of underground haulage in which the weight of the empty cars is sufficient to draw the rope in. Fay main separation door A wooden or steel door erected near the pit bottom to prevent the intake air leaking into the main return airway or upcast shaft; a door to direct the main intake air in toward the workings. It may be fitted with an appliance, or shutter, to ease the opening for traveling purposes. See also: fan drift doors mains firing Firing blasts from a mains supply. McAdam, 2 main shaft The line of shafting that receives its power directly from the engine or motor and transmits power to other parts. Crispin mains lighting A system of underground mine lighting in which the lamps are fed from the main electrical supply. It is used principally at the pit bottom, using filament lamps in either transparent well glass or prismatic bulkhead fittings. Nelson main-slope engineer In bituminous coal mining, one who operates the hoisting engine for raising or lowering workers, material, coal, and rock along the main haulage slope (incline) of a mine having one or more auxiliary or relay slopes. DOT maintaining levels 1892

In quarrying, consists of the removal by blasting of rock protruding above the level of the quarry floor or bench, to allow the movement of loading and transport equipment. Streefkerk maintenage Fr. The face of workings in inclined or vertical seams consisting of a series of steps each about 6 ft (1.8 m) high, and forming the working place for one person. Fay maintenance Proper care, repair, and keeping in good order. Crispin main tie Tension member connecting the feet of a roof truss, usually at the level of bearing on the wall plate or padstone. Hammond main transport The conveying or haulage of mined material from the mining area subsidiary transport to the shaft bottom or surface. For the main transport of coal, the trend is toward trunk conveyors or locomotive haulage. See also: subsidiary transport; underground haulage. Nelson main way A gangway or principal passage. Fay maitlandite See: thorogummite Majac mill A mill for dry-grinding mica by means of fluid energy. It consists of a chamber containing two horizontal directly opposed jets. Mica is fed continuously from a screw conveyor into this chamber. The particle size of the product from this mill can be controlled over a broad range down to the micrometer sizes. USBM, 7 major diameter Formerly called outside diameter. It refers to the largest diameter of a thread on a screw or nut. Crispin 1893

major face Used in widely different meanings in different manufacturing plants; the meaning of the term depends on the special process of cutting used. Thus, the faces of the major rhombohedron r 1011 are spoken of as the major face when BT wafers are cut directly from a faced mother crystal. Also applied to the prism faces that terminate in the faces of the major rhombohedron, etc. Am. Mineral., 2 major mine disaster Defined by the Mine Safety and Health Administration, U.S. Department of Labor, as any accident that results in the death of five or more persons. Federal Mine Safety major principal plane The plane normal to the direction of the major principal stress. ASCE major principal stress The largest (with regard to sign) principal stress. ASCE make A wide portion of a lode. CF: pinch make gas Mid. To yield or produce gas. A seam of coal that gives off combustible gas is said to make gas. Fay make of water The rate of entry of water into a mine or part of a mine. Also called growth. BS, 10 makeup To assemble; to couple or screw together. Usually applied to the process of assembling the component parts of a drill string or pipe system. Long makeup bunker See: makeup shed makeup medium 1894

Medium or medium solids added to the circuit to replace losses during the separating operation. BS, 5 makeup shed A surface building at which explosives, drawn from the magazine, are issued and where the charges are prepared or made up. Syn: makeup bunker makeup time The time required to couple together the component parts of a drill or casing string and the lowering of such a string to the working position in a borehole. Long makeup water a. Water supplied to a washery to replace that lost from the circuit. BS, 5 b. Water supplied to replenish that lost by leaks, evaporation, etc. Strock, 2 making hole a. The depth gained in the day's drilling. Hess b. The act of, or portion of work time spent in, actual drilling and advancement of a bore or drill hole. makings Newc. The small coal hewn out in undercutting or channeling. Also, in some localities, called bug dust. Fay malachite A monoclinic mineral, Cu2 CO3 (OH)2 ; dimorphous with georgeite; bright green; occurs with azurite in oxidized zones of copper deposits; a source of copper. Syn: Atlas ore malacolite a. A pale-colored, translucent variety of diopside with good (001) parting; also diopside from Sala, Sweden. b. See: diopside malacon A metamict variety of zircon. Also spelled malakon, malacone. maldonite

1895

An isometric mineral, Au2 Bi ; pink to silver-white; intermetallic compound. Syn: black gold male thread See: pin thread maletra furnace A hand reverberatory furnace for roasting finely divided ore entirely without the aid of extraneous heat. Fay malignite A mafic nepheline syenite. Fifty percent of the rock is composed of aegirine-augite; the remainder is nepheline and orthoclase in about equal amounts. Accessories include apatite, biotite, titanite, and opaque oxides. malinite An aluminous variety of halloysite. malinowskite A variety of tetrahedrite that contains lead and silver. Standard, 2 mall Eng. A heavy hammer. A drawing or prop mall is a long-handled mall used when withdrawing timber. SMRB malladrite A trigonal mineral, Na2 SiF6 . (Not mallardite.) mallan Soft turf containing lumps of ore, Derbyshire, U.K. mallardite A monoclinic mineral, MnSO4 .7H2 O ; melanterite group. (Not malladrite.) malleability 1896

a. The characteristic of metals that permits plastic deformation in compression without rupture. See also: plastic deformation ASM, 1 b. Minerals are malleable when slices cut from them may be flattened out under a hammer. Examples are native gold; silver; copper; platinum. Nelson malleable a. Said of a mineral, e.g., gold, silver, copper, platinum, that can be plastically deformed under compressive stress, e.g., hammering. AGI b. A mineral that can be sliced and the slices hammered flat without breaking, e.g., gold, copper. CF: sectile; flexible. malleable cast iron A cast iron made by a prolonged anneal of white cast iron in which decarburization or graphitization, or both, take place to eliminate some or all of the cementite. The graphite is in the form of temper carbon. If decarburization is the predominant reaction, the product will have a light fracture, (whiteheart malleable); otherwise, the fracture will be dark (blackheart malleable). Pearlitic malleable is a blackheart variety having a pearlitic matrix along with, perhaps, some free ferrite. See also: iron malleable mineral A mineral that may be flattened or deformed by hammering without breaking, for example, native copper or gold. Stokes malleable nickel Nickel obtained by remelting and deoxidizing electrolytic nickel and casting it into ingot molds. It can be rolled into sheet and used in equipment for handling food, and for coinage, condensers, and other purposes where resistance to corrosion, particularly by organic acids, is required. CTD malleablizing Annealing white cast iron in such a way that some or all of the combined carbon is transformed to graphite or, in some instances, part of the carbon is removed completely. ASM, 1 malleate To shape into a plate or leaf by beating or hammering; said of metal. Standard, 2 malmstone

1897

a. A hard, cherty, grayish-white sandstone, specif. the Malmstone from the upper part of the Upper Greensand (Cretaceous) of Surrey and Sussex in England, used as a building and paving material. AGI b. A marly or chalky rock. AGI malpais A term used in the Southwestern United States and Mexico for a region of rough and barren lava flows. The connotation of the term varies according to the locality. Etymol: Spanish, mal pais, bad land. AGI maltesite A variety of andalusite, resembling chiastolite, showing in cross section a maltese cross of pure material separated by areas of impure material. English maltha a. Various natural tars resulting from the oxidation and drying of petroleum. See also: mineral tar; pittasphalt. AGI b. A black viscid substance intermediate between petroleum and asphalt. Also called malthite. Webster 3rd c. A variety of ozocerite. Webster 2nd malthacite A scaly, sometimes massive, white or yellowish clay related to fuller's earth, having a SiAl ratio of about 4. AGI mammillary Of, or pertaining to, smoothly rounded masses resembling breasts or portions of spheres; descriptive of the shape of some mineral aggregates, such as malachite or limonite; similar to but a larger size than botryoidal. Fay mammillary structure See: pillow structure mammillated Said of a mineral displaying large spheroidal surfaces, e.g., malachite. Nelson managerial organization Coordination of functional units and presentation of the results of their achievements in policy-guiding form as facts, conclusions, and recommendations. Efficient integration of the operations managed. Pryor, 3 1898

manandonite An orthorhombic mineral, Li2 Al4 (Si2 AlB)O10 (OH)8 ; kaolinite-serpentine group. manasseite a. A hexagonal mineral, Mg6 Al2 (CO3 )(OH)16 .4H2 O ; dimorphous with hydrotalcite. b. The mineral group barbertonite, chlormagaluminite, manasseite, and sjoegrenite. manchado a. Spotted ore, Spain. b. A commercial grade of mica which is stained to very slightly spotted, Brazil. Manchurian jade See: soapstone mandelstone See: amygdaloid mandrel a. A miner's pick. Webster 3rd b. A usually tapered or cylindrical axle spindle, or arbor that is inserted into a hole in a piece of work so as to support the work during machining. Webster 3rd c. A metal bar that serves as a core around which metal or other material may be cast, molded, forged, bent, or otherwise shaped. Webster 3rd d. Any of a train of jointed units intended to be pulled through an underground duct as each joint is made to ensure perfect alinement, or through a steel pipe in process of welding to ensure a smooth interior. Webster 3rd e. The shaft and bearings on which a tool (as a grinding disk or circular saw) is mounted. Webster 3rd f. A temporary interior support for a thinwalled tube (as a tubular steel pile to be filled later with concrete) being driven into something. Webster 3rd mandril A miner's pick. Nelson Manebach law A type of twinning in the monoclinic crystal system. The basal pinacoid is the twinning plane. Hess Manebach twin 1899

A monoclinic crystal twinned across the basal pinacoid, according to the Manebach law, e.g., orthoclase. man engine See: man machine manganandalusite A variety of andalusite containing 6.91% Mn2 O3 . It differs from ordinary andalusite in its grass-green color and strong pleochroism. From Vestana, Sweden. English manganberzeliite An isometric mineral, (Ca,Na)3 (Mn,Mg)2 (AsO4 )3 ; forms a series with berzeliite and is yellow to orange. manganblende See: alabandite mangandalusite Variety of andalusite containing manganese. Alternate spelling of manganandalusite. manganepidote See: piemontite manganese A gray-white, hard, brittle metallic element. Symbol, Mn. Manganese does not occur uncombined in nature, but its minerals are widely distributed. Pyrolusite (MnO2 ) and rhodochrosite (MnCO3 ) are the most common minerals. The discovery of large quantities of manganese nodules on the ocean floor, containing about 24% manganese, holds promise as a source of manganese. Used to form many important alloys, esp. with steel, aluminum, and antimony; used in dry cells and glass, and in the preparation of oxygen, chlorine, and medicines. Handbook of Chemistry and Physics, 3 manganese-aluminum garnet See: spessartine manganese bronze 1900

Alloy of 59% copper, 1% tin, and up to 40% manganese. Practically a brass with high tensile strength and toughness. Used for ship's impellers and such fittings as must withstand corrosion by seawater. Pryor, 3 manganese garnet See: spessartite manganese glance See: alabandite manganese-hoernesite A monoclinic mineral, (Mn,Mg)3 (AsO4 )2 .8H2 O; vivianite group. manganese hydrate See: wad manganese minerals Those in commercial production are pyrolusite, psilomelane, braunite, and manganite. Manganese is used chiefly in steel manufacture. manganese nodules The concretions, primarily of manganese salts, covering extensive areas of the ocean floor. These vary in size from extremely small to some 6 in (15.2 cm) in diameter. They have a layer configuration and may prove a useful source of minerals. Hy manganese ore A term used for ore containing 35% or more manganese; it may include concentrate, nodules, or synthetic ore. manganese oxide There are several manganese oxides, the commonest being MnO2 (pyrolusite). It is used as a coloring oxide (red or purple); mixed with the oxides of cobalt, chromium, and iron, it produces a black. This oxide is also used to color facing bricks, and to promote adherence of ground-coat vitreous enamels to the base metal. See also: manganite; psilomelane. Dodd manganese sicklerite 1901

See: sicklerite manganese silicate See: rhodonite. manganese spar See: rhodonite; rhodochrosite. manganiferous iron ore A term used for iron ores containing 5% to 10% manganese. manganiferous ore A term used for any ore of importance for its manganese content containing less than 35% manganese but not less than 5%. See also: natural ore manganite A monoclinic mineral, MnO(OH) ; trimorphous with feiknechtite and groutite; a hydrothermal vein mineral; an ore of manganese. Syn: gray manganese ore; sphenomanganite. mangan-neptunite A monoclinic mineral, KNa2 Li(MN,Fe)2 Ti2 Si8 O24 ; forms a series with neptunite. See also: neptunite manganocalcite A variety of calcite that contains manganese carbonate and is closely related to rhodochrosite. Syn: kutnohorite manganolangbeinite An isometric mineral, K2 Mn2 (SO4 )3 ; rose-red; forms tetrahedra in cavities in recent lavas on Mt. Vesuvius, Italy. manganolite a. See: rhodonite. b. A general term for rocks composed of manganese minerals, esp. manganese oxides such as wad and psilomelane. AGI 1902

manganophyllite A manganoan variety of biotite. manganosiderite An intermediate member of the rhodochrosite-siderite series. manganosite An isometric mineral, MnO ; periclase group; emerald-green; forms octahedra that blacken on exposure to air. manganotantalite An orthorhombic mineral, MnTa2 O6 ; dimorphous with manganotapiolite; forms series with manganocolumbite and with ferrotantalite. manganpyrosmalite A hexagonal mineral, (Mn,Fe)8 Si6 O15 (OH,Cl)10 ; dimorphous with brokenhillite; forms a series with ferropyrosmalite. mangrove coast A tropical or subtropical low-energy coast with a shore zone overgrown by mangrove vegetation. Such coasts are common in Indonesia, Papua New Guinea, and other tropical regions. The marine coast of southern Florida is the only significant U.S. example. AGI manhole a. A safety hole. Hudson b. Cubicles cut into the solid strata or built into the gob pile along haulageways in which miners can be safe from passing locomotives and cars. Also called refuge hole. BCI c. A refuge hole constructed in the side of a gangway, tunnel, or slope. Fay d. A small and generally very short passage used only for the ingress and egress of the miners. Fay e. A hole in cylindrical boilers through which a worker can get into the boiler to examine and repair it. Fay f. A small passage connecting a level with a stope, or with the level next above. Webster 2nd manhole cover A movable cast-iron plate fitting a cast-iron frame bedded on a rebated concrete slab or kerb over a manhole. Covers over foul drains are formed to prevent escape of foul air. Hammond 1903

manila rope Broadly, rope or cordage formed from twisted fibers obtained from abaca, agave, or hemp plants. Long manipulated variable In mineral processing, a quantity or condition that is varied as a function of the actuating signal so as to change the value of the controlled variable. Fuerstenau manipulator a. A machine for moving and turning over hot billets or blooms of iron or steel in the process of rolling. Standard, 2 b. A mechanical device used for safe handling of radioactive materials. Frequently, it is remotely controlled from behind a protective shield. Lyman manless coal face A coal face mined by remotely controlled equipment that eliminates the need for workers in dangerous places. Encyclopaedia Britannica manless coal mining Longwall coal faces equipped for the automatic starting, stopping, and steering of power-loading machines as well as the manipulation of electric trailing cables, including air and water hoses; controlled automatic advancing of face conveyors as well as advancing and setting of roof supports. Each and all operations are correctly phased and accomplished from a remote point. With the advent of electronics and automation techniques, the prospects of manless coal mining are very promising. Nelson manless face A longwall face on which the coal is cut and brought out to the gate road mechanically, without the aid of miners on the face. The face is unsupported. In general, the coal seam is thin but of high grade, and some type of rapid plow is employed. See also: coalsensing probe; ram scraper. Nelson manlock An air lock through which workers pass to a working chamber that is under air pressure. Hammond man machine 1904

Corn.; Derb. An obsolete term for a mechanical lift for lowering and raising miners in a shaft by means of a reciprocating vertical rod of heavy timber with platforms at intervals, or of two such rods moving in opposite directions. In the former case, stationary platforms are placed in the shaft, so that the miner in descending, for instance, can step from the moving platform at the end of the downstroke and step back upon the next platform below at the beginning of the next downstroke. When two rods are employed, the miner steps from the platform on one rod to that on the other. Syn: man engine; movable ladder. Fay manmade diamond Diamond produced synthetically. Also called MM diamond. See also: diamond; synthetic diamond. Long Mannheim process Contact method of catalyzing SO2 to SO3 in two stages, using first iron oxide and second platinized asbestos as catalysts. Pryor, 3 Manning's formula An empirical formula for the value of the coefficient, C, in the Chezy formula, the factors of which are the hydraulic radius and a coefficient of roughness; a simplification of the Kutter formula. Seelye, 1 man-of-war Staff. A small pillar of coal left in a critical spot; also, a principal support in thick coal workings. Fay manometer a. Any instrument that measures gaseous pressure. Nelson b. Measures pressure or a pressure difference by balancing the applied pressure against the hydrostatic head of a column of liquid of known density. In practice, most manometers measure a pressure difference, so that if an absolute pressure is to be measured, it is essential to have access to an accurate barometer to determine the atmospheric pressure. Roberts, 1 c. An instrument designed to give a continuous record of the pressure of an explosion at the point where the instrument is located. See also: micromanometer; piezometer; two-liquid differential manometer; U-tube manometer; vernier-reading manometer; water gage. Rice, 2; Roberts, 1 manometer calibration

1905

Many manometers require calibration, and this may be carried out by the (1) static method in which simultaneous readings of the manometer under test and the primary standard are taken when one limb of the manometer and the standard are connected to a variable pressure source, the other limbs being connected to a source of constant pressure, or (2) the dynamic method in which the difference in pressure obtained between a low-speed atmospheric wind-tunnel hole (static pressure) and the atmospheric static pressure is used to carry out the calibration. One limb of the manometer and the low-pressure side of the Chattock-Fry are connected to the tunnel-wall hole (reference variable pressure), while the other limb of the manometer is connected to the atmospheric outlet of the Chattock-Fry. Roberts, 1 manometric efficiency a. The ratio of the actual head developed to the velocity pressure of air moving at the fantip speed, equal to one-half the theoretical head of a radial-tip fan. Hartman, 1 b. An indication of the capability of the fan to produce pressure. It is the ratio of the initial depression to the theoretical depression. Manometric efficiency = 4,380 total water gage / U2 , where U = tip speed in feet per second of fan blades. Nelson c. The chief value of the manometric efficiency lies in its being a rough check on the mechanical efficiency of the fan. See also: theoretical depression manoscope See: manometer manoscopy The science of determining the density of gases and vapors. Standard, 2 man-riding car A car or carriage designed for the riding of miners to and from the workings. The car body has a low center of gravity to avoid the risk of overturning and is fitted with track brakes and an overspeed clutch. The train set is arranged to brake from the rear to avoid pileup, and the brakes are applied immediately on overspeed from a preset velocity. Nelson man-riding conductor A worker appointed by the mine manager to be in charge of the running of a train of manriding cars. This worker is the responsible person for starting and stopping the vehicles, for giving the proper signals, and for seeing that the safe seating capacity is not exceeded. During the shift this worker is employed on other duties. Nelson mansfieldite 1906

An orthorhombic mineral, AlAsO4 .2H2 O ; variscite group; forms a series with scorodite. manshift The output or work done by a worker in one shift; a basis for assessing the magnitude of a job to complete. Nelson Man-Ten steel alloy An alloy containing 0.35% carbon as maximum, from 0.25% to 1.75% manganese, 0.10% to 0.30% silicon, 0.01% to 0.25% copper, 0% to 0.40% molybdenum, and 0% to 0.20% vanadium. Used for bodies and doors of stripping shovel dippers, which have manganese steel for bail, lip, and renewable teeth. Lewis mantle a. The soil or other unconsolidated rock material commonly referred to as overburden. See: surface b. A sheath of manganese steel that fits over the iron or steel cone of the breaking (gyrating) head of a gyratory crusher. Pryor, 3 c. That part of a blast furnace that carries the weight of the stack, continuing up from the bosh. Pryor, 3 d. See: mantle rock; regolith. e. The outer zone in a zoned crystal; an overgrowth. AGI f. The zone of the Earth below the crust and above the core, which is divided into the upper mantle and the lower mantle, with a transition zone between. AGI mantle rock See: regolith manto A flat-lying, bedded deposit; either a sedimentary bed or a replacement strata-bound orebody. Etymol: Spanish, vein, stratum. CF: bed vein AGI manual haulage The practice of pushing tubs, trams, etc., by hand. See also: hand tramming manual takeup A hand-operated mechanism for adjusting the takeup or movable pulley. NEMA, 2 manual-type belt-tensioning device

1907

A hand-operated mechanism for adjusting a takeup pulley to vary the tension in a conveyor belt. The most common types are chain-jack, sylvester, rack, and screw. NEMA, 1 manual winding control A system in which the winder is controlled in the conventional manner by the driver, following the usual bell signals from the onsetter and the banksman. The system of control ensures that the speed of the winder follows closely the position of the driver's level, driving or dynamic braking being applied automatically to the motor as needed to preserve the chosen speed. See also: automatic cyclic winding manufactured gas A mixture of gaseous hydrocarbons produced from coal or oil. See also: gas manufactured marble a. A mixture of marble dust and plastics. b. A mixture of powdered stone and plastics. manufactured sand Fine aggregate produced by crushing rock. AIME, 1 manway a. A compartment, vertical or inclined, for the accommodation of ladders, pipes, and timber chutes. The drivage may be a winze or a raise and its purpose is to give convenient access to a stope. Also called ladderway. Nelson b. A passageway for the use of miners only; an airshaft; a chute. Standard, 2 c. Eng. See: manhole d. A passage in or into a mine used as a footpath for workers. Korson e. A short heading between two chutes. map a. A horizontal projection of surface plants, mine workings, or both, drawn to a definite scale, upon which is shown all the important features of the mine; a plan; a plat. b. The act of preparing such plans of a mine. c. A representation to a definite scale on a horizontal plane of the physical features of a portion of the Earth's surface (natural or artificial or both) by means of symbols, which may emphasize, generalize, or omit certain features as conditions may warrant. A map may be derived from ground surveys made by transit, plane table, or camera, or from aerial photographic surveys, or both. Seelye, 2 map projection 1908

A method of representing the curved surface of the Earth on a flat map. As the true shape of the Earth is a globe, it is impossible to make a map of large areas of the Earth's surface without some distortion. Hammond marathon mill A form of tube mill used in the cement industry, in which the pulverizing is done by long pieces of hardened steel shafting. Liddell marbella A Spanish magnetite with a siliceous gangue. Osborne marble a. A metamorphic rock composed essentially of calcite, dolomite, or a combination of the two, with a fine- to coarse-grained crystalline texture. b. In commerce, any crystalline carbonate rock that will take a polish, including true marble, certain coarsegrained limestones, alabaster, and onyx. c. See: verde antique marble handsaw A toothless blade fitted at the back with a block handle, used with sand, for cutting slabs of marble into pieces. Fay marble saw A toothless blade used with sand in marble cutting. Standard, 2 Marble's reagent An etchant for stainless steels, consisting of 4 g of copper sulfate in 20 mL of hydrochloric acid and 20 mL of water. Osborne marcasite a. White iron pyrites, FeS2 , the orthorhombic dimorph of pyrite, having a lower specific gravity, less stability, and a paler color. Often called white iron pyrites, coxcomb pyrites, and spear pyrites. AGI b. In the gemstone trade, marcasite is either pyrite, polished steel (widely used in ornamental jewelry in the form of small brilliants), or even white metal. CTD c. An orthorhombic mineral, FeS2 ; dimorphous with pyrite; metallic; bronzeyellow to white; an authigenic or supergene mineral from acid solutions. Syn: white iron pyrites; white pyrite; cockscomb pyrite; spear pyrite; lamellar pyrite. d. The mineral group ferroselite, frohbergite, hastite, kullerudite, marcasite, and mattagamite. e. A 1909

gemstone with a metallic luster, esp. pyrite, but including polished steel and white metal. Syn: radiated pyrite marcus A patented shaker screen with a nonharmonic or quick-return motion. Zern Marcy mill A ball mill in which a vertical-grate diaphragm is placed near the discharge end. Between this perforated diaphragm and the end of the tube, there are arranged screens for sizing the material, oversize being returned for further grinding while undersize is discharged. Liddell mare ball York and Lanc. Spherical ferruginous concretions. CF: caballa ball Arkell marekanite Obsidian that occurs as rounded to subangular bodies, usually less than 2 in (5.1 cm) in diameter and having indented surfaces. These bodies occur in masses of perlite and are of special interest because of their low water content as compared with the surrounding perlite. The name is from the Marekanka River, Okhotsk, Siberia, Russia. AGI margarite a. A beadlike string of globulites, commonly found in glassy igneous rocks. AGI b. A monoclinic mineral, 4[CaAl2 (Al2 Si2 O10 )(OH)2 ] ; mica group; forms brittle folia; associated with corundum. Syn: brittle mica; pearl mica. margarodite A pearly variety of muscovite. margarosanite A triclinic mineral, Pb(Ca,Mn)2 Si3 O9 . marginal deposit a. A magmatic segregation at the bottom and periphery of an intrusive rock; e.g., nickelcopper-sulfide deposits at Sudbury, ON, Canada. b. Marginal ore deposit. marginal fissure 1910

A fracture, bordering an igneous intrusion, that has become filled with magma. AGI marginal ore deposit A deposit near the lower limit of commercial workability. Bateman, 2 marginal reserves That part of the reserve base that, at the time of determination, borders on being economically producible. Its essential characteristic is economic uncertainty. Included are resources that would be producible, given postulated changes in economic or technologic factors. USGS, 2 marginal sea An adjacent sea that is widely open to the ocean. See also: adjacent sea marginal thrust A thrust fault along the margin of an intrusive that dips toward the intrusive. AGI marginal trench See: trench maria glass An early name for both mica and selenite (gypsum). marialite A tetragonal mineral, 3NaAlSi3 O8 .NaCl ; scapolite group; forms a series with meionite. Marietta miner Trade name for a heavy track-mounted continuous miner for operation in thick seams. The front end contains two cutter arms that rotate in opposite directions to sweep the coal it cuts inwards toward the center. The broken coal is taken back through the machine to a chain conveyor. Two cutter chains are arranged at roof and floor level behind the arms to cut down the coal left between the rotating arms. The machine cuts an area 12 ft (3.7 m) wide and 7 ft (2.1 m) high. Power is supplied by two motors, one of 70 hp (52.2 kW) and the other of 25 hp (17.4 kW). It has a continuous capacity from 3 to 3-1/2 st/min (2.7 to 3.2 t/min). This machine has been subject to several modifications. See also: continuous miner 1911

marine biology Science that treats of the living organisms of the sea, the chemical and physical characteristics of their environment, and factors affecting their distribution. Hy marine core drill Used for investigating strata beneath the seabed and taking sample and cores from which dredging conditions may be assessed. Hammond marine deposit A sedimentary deposit laid down in the sea, usually beyond the seaward edge of the littoral belt. Stokes marine erosion Erosion by moving seawater, the action of which is largely intensified by detritus carried by it. Schieferdecker marine geology The marine science that treats of the topographical features of the sea bottom, the phenomena that have developed it, and the types, processes, and distribution of sedimentation. Hy marine humus Organic matter deposited on the sea bottom. Tomkeieff marine invasion The spreading of the sea over a land area. AGI marine mining The mining of marine mineral deposits, classified as unconsolidated deposits such as gravel, mineral sands, or nodules; consolidated deposits such as outcrops, veins, or crusts; and fluid that is seawater or hydrothermal fluids; from, on, or beneath the seabed, whether on the continental shelf or in the deep ocean basins. SME, 1 marine transgression See: transgression 1912

mariposite A chromian variety of phengite, a siliceous variety of muscovite. maritime plants Plants that grow naturally under salty conditions on a foreshore and that may materially help to prevent scour and stabilize sand dunes. Hammond marker a. An easily recognized stratigraphic feature having characteristics distinctive enough for it to serve as a reference or datum or to be traceable over long distances, esp. in the subsurface, as in well drilling or in a mine working; e.g., a stratigraphic unit readily identified, or any recognizable rock surface such as an unconformity or a corrosion surface. See also: format marker formation. CF: horizon b. A layer that yields characteristic reflections over a more or less extensive area. AGI c. A layer that accounts for a characteristic segment of a seismic-refraction time-distance curve and can be followed over reasonably extensive areas. AGI d. S. Afr. See: outcrop e. See: marker block marker bed a. See: marker b. A stratigraphic bed selected for use in preparing structural, paleogeologic, and other maps that emphasize the nature or attitude of a plane or a surface. It is generally selected for lithologic characteristics, but biologic factors and unconformities may control. Syn: indicator; key bed; marker horizon. See also: horizon; marker. CF: indicator marker block A small block on which the footage below the collar of a borehole is marked and inserted between pieces of core at its appropriate place in a core box to indicate the depth in the borehole at which the core was obtained. Also called footage block; footmark; marker. The marker block is placed in the core box on completion of each drilled interval. See also: marker marker formation See: marker marker horizon See: marker bed; marker. 1913

market pot In silver refining, the pot at the end of the series of pots used in the Pattinson process, in the direction in which the amount of silver left in the lead is diminishing. It contains the market lead. Fay markovnikovite Variety of petroleum found in Russia. Tomkeieff marl a. An old term loosely applied to a variety of materials, most of which occur as loose, earthy deposits consisting chiefly of an intimate mixture of clay and calcium carbonate, formed under marine or esp. freshwater conditions; specif. an earthy substance containing 35% to 65% clay and 65% to 35% carbonate. Marl is usually gray; it is used esp. as a fertilizer for acid soils deficient in lime. In the Coastal Plain area of Southeastern United States, the term has been used for calcareous clays, silts, and sands, esp. those containing glauconite (greensand marls); and for newly formed deposits of shells mixed with clay. AGI b. A soft, grayish to white, earthy or powdery, usually impure, calcium carbonate precipitated on the bottoms of present-day freshwater lakes and ponds, largely through the chemical action of aquatic plants, or forming deposits that underlie marshes, swamps, and bogs that occupy the sites of former (glacial) lakes. The calcium carbonate may range from 90% to less than 30% . Syn: bog lime c. A term occasionally used (as in Scotland) for a compact, impure, argillaceous limestone. Etymol: French marle. AGI marlite See: marlstone marl slate An English term for calcareous shale; it is not a true slate. AGI marlstone a. An indurated rock of about the same composition as marl. It has a blocky subconchoidal fracture, and is less fissile than shale. Syn: marlite b. A term originally applied by Bradley (1931) to slightly magnesian calcareous mudstones or muddy limestones in the Green River Formation of the Uinta Basin, UT, but subsequently applied to associated rocks (including conventional shales, dolomites, and oil shales) whose lithologic characters are not readily determined. Picard (1953) recommended abandonment of the term as used in the Uinta Basin. AGI c. See: marlstone ore 1914

marlstone ore A stratified ironstone located in the Midlands (England) and occurring at the top of the Middle Lias series. Nelson marly Pertaining to, containing, or resembling marl; e.g., marly limestone containing 5% to 15% clay and 85% to 95% carbonate, or marly soil containing at least 15% calcium carbonate and no more than 75% clay (in addition to other constituents). AGI marmarization See: marmorization marmarosh diamond Rock crystal variety of quartz. marmatite A ferroan variety of sphalerite. marmolite A thinly foliated variety of serpentine. marmorization The conversion of limestone into marble by metamorphism. Syn: marmarization; marmorosis. marmorosis See: marmorization marm stone Obsolete term for marble. Arkell marokite An orthorhombic mineral, CaMn2 O4 ; opaque black with dark red internal reflection; in Morocco. 1915

Marriner process A modification of the cyanide process in which the ore is deadroasted, after which all of it is ground to slime, and the resulting product is treated by agitation. Liddell marrow a. Well sinkers' term for a fine-grained floury rock, Oxfordshire, U.K. b. Up to six workers who pool and share earnings equally, all at the same workplace but not necessarily on the same shift. Marsaut lamp An earlier type of miners' flame safety lamp fitted with two or three conical gauzes, thus adding to the safety of the lamp when used in high air velocities. The Marsaut lamp is the basis of modern flame safety lamps. Nelson marsh buggy A special, self-propelled geophysical vehicle designated to operate over marsh or extremely soft ground, usually having wheels with very wide tread or buoyant wheels that will float the vehicle in water. AGI Marsh funnel An appliance for measuring viscosity. It consists of a copper funnel, about 30 cm long with a 15-cm diameter at the top, that has a 10-mesh screen over half its diameter to remove debris and a 6-mm-diameter exit tube at the bottom through which the rate of flow is timed. It takes 26 s for a quart of clean water to flow through and correspondingly longer for muds of greater viscosity. Gel strength is measured by comparing the rate of flow of freshly agitated mud with that of mud that has been allowed to remain quiescent for 10 min. See also: hydrometer; specific-gravity hydrometer. Nelson marsh gas a. Methane, CH4 . If the decaying matter at the bottom of a marsh or pond is stirred, bubbles of methane rise to the surface, thus the name marsh gas. Nelson b. It is nonexplosive until met with air or oxygen. In miners' language synonymous with firedamp. See also: methane; firedamp. BCI; Fay marshite An isometric mineral. CuI ; soft; oil brown; dodecahedral cleavage; at Broken Hill, New South Wales, Australia. 1916

marsh ore See: bog iron; bog iron ore. marsh pan A salt pan in a marsh. AGI martenite A synthetic fettling material, used for sintering open-hearth furnace bottoms. The approximate composition (variable) is 5.2% silica, 2.1% alumina, 10.5% ferric oxide, 13.4% lime, 66.5% magnesia (ignition loss, 2.3%). Martenite sinters more rapidly than magnesite, thereby reducing repair time; moreover, it is suitable for hot patching. Martenite is as wear resistant as magnesite and has no deleterious effect on the slag. Osborne martensite Alpha-iron supersaturated with carbon as a result of quenching austinite (gamma-iron) below 150 degrees C. (Not martinsite.) martic A mixture of bituminous matter, such as asphalt, and some foreign material, such as sand. Mersereau, 2 Martin process Used in the manufacture of steel. Also called Siemens-Martin and open-hearth process. Fay martinsite See: kieserite martite Hematite pseudomorphous after magnetite octahedra. martourite See: berthierine marundite 1917

A coarse-grained pegmatite consisting of corundum and margerite with accessory biotite, plagioclase, apatite, tourmaline, garnet, and kyanite. Allied to plumasite grading into normal pegmatite. Hess mascagnite An orthorhombic mineral, (NH4 )2 SO4 ; occurs around fumaroles and in guano deposits. mascot emerald A beryl triplet that simulates emerald. maser Contracted version of microwave amplification by simulated emission of radiation. A class of amplifier from which the optical laser was developed. See also: laser mask a. A screen, usually made of tracing cloth, to subdue and diffuse the light behind a plumbline or other sighted object. BS, 7 b. See: respirator maskeeg See: muskeg maskelynite A plagioclase glass in some chondrites and irons formed by preterrestrial impact between meteorites in space. mason's hammer A square-faced hammer with a peen in line with handle. Standard, 2 mass a. The quantity of matter in a body, obtained by dividing the weight of the body by the acceleration due to gravity. b. A large irregular deposit of ore, which cannot be recognized as a vein or bed. See also: nontabular deposit mass aqua Borosilicate glass imitative of aquamarine (beryl). 1918

mass copper In the Lake Superior region, a term for native copper occurring in large masses. mass density Mass of air per unit volume. Measured in kilograms per cubic meter. Hartman, 2 mass detonation A term applied to the unintentional detonation of all or a part of a large quantity of explosive material (bulk truckload, shipload, or caseload) by the explosion of a smaller quantity of explosives or a flame. mass diagram A plotting of cumulative cuts and fills used for engineering computation of highway jobs. Nichols, 1 mass effect The tendency for hardened steel to decrease in hardness from the surface to the center, as a result of the variation in the rate of cooling throughout the section. Becomes less marked as the rate of cooling required for hardening decreases; i.e., as the content of alloying elements increases. CTD mass fiber a. One of the three recognized forms in which asbestos fiber is found in rock deposits. In this form the fibers are usually found intermixed in a matrix, which forms the orebody. Found mostly in the matrix of the deposits of the amphibole varieties of asbestos. The rock forming the orebody is sometimes inclined to be soft, and the fibers intermingled in such a mass deposit consist of patches of apparent slip-fiber forms. Indications of disturbed cross-fiber disposition are often discernible. Sinclair, 7 b. A mass aggregate of interlaced, unoriented, or radiating fibers of chrysotile serpentine asbestos. mass haul diagram Diagram used in construction work to show the location of digging and filling sites, and the distances over which earth and materials are to be transported. Pryor, 3 massicot An orthorhombic mineral, PbO ; dimorphous with litharge; prismatic cleavage; soft; yellow; occurs in oxidized zones of lead ore deposits. Syn: lead ocher 1919

massif A massive topographic and structural feature, esp. in an orogenic belt, commonly formed of rocks more rigid than those of its surroundings. These rocks may be protruding bodies of basement rocks or younger plutonic bodies. Examples are the crystalline massifs of the Helvetic Alps, whose rocks were deformed mainly during the Hercynian orogeny, long before the Alpine orogeny. AGI massifs long Fr. Pillar in longwall workings. Fay massive a. Said of a mineral deposit (esp. of sulfides) characterized by a great concentration of ore in one place, as opposed to a disseminated or vein deposit. b. Said of any rock that has a homogeneous texture or fabric over a wide area, with an absence of layering, foliation, cleavage, or any similar directional structure. See also: massive rock c. Said of a mineral that is physically isotropic; i.e., lacking a platy, fibrous, or other structure. CF: amorphous massive bedding Very thick homogeneous stratification in sedimentary rocks. massive eruption Outpouring of lava from a line or system of fissures, so that vast areas have become covered by nearly horizontal sheets of extrusive flows. massive mineral If the crystalline grains are so small that they cannot be distinguished except under the high magnification of a microscope, the structure is described as compact and the mineral as massive. CMD massive pluton Any pluton that is not tabular in shape. massive rock Isotropic, homogeneous rock with a strength that does not vary appreciably from point to point. Typical examples are igneous rocks such as granite and diorite; metamorphic 1920

rocks such as marble and quartzite; and some thick-bedded sedimentary rocks. See also: massive mass movement The unit movement of a portion of the land surface; specif. the gravitative transfer of material down a slope. Syn: mass-wasting AGI mass number The sum of the neutrons and protons in a nucleus. It is the nearest whole number to the actual atomic weight of the atom. Lyman mass profile A road profile showing cut and fill in cubic yards or meters. Nichols, 1 mass shooting Simultaneous exploding of charges in all of a large number of holes, as contrasted with sequential firing with delay caps. Nichols, 1 mass spectra Positive ray spectra obtained by means of a mass spectrograph. In such spectra the images due to positive ray particles of different masses are spaced according to the masses of the particles; i.e., according to their atomic weights. CTD mass spectrometer An instrument for producing and measuring, usually by electrical means, a mass spectrum. It is esp. useful for determining molecular weights and relative abundances of isotopes within a compound. AGI mass unit weight See: wet unit weight mass-wasting See: mass movement mast

1921

a. A drill derrick or tripod mounted on a drill unit, which can be raised to its operating position by mechanical means. Long b. A single pole, used as a drill derrick, supported in an upright or operating position by guys. Long c. A tower or vertical beam carrying one or more load lines at its top. Nichols, 1 master alloy An alloy, rich in one or more desired addition elements, that can be added to a melt to raise the percentage of a desired constituent. ASM, 1 master hauler S. Wales. The person in charge of haulers in a coal mine and who controls the horse haulage traffic and the allocation of trams. Nelson master joint A persistent joint plane of greater-than-average extent. AGI master lode The main productive lode of a district. CF: mother lode master pin The only pin in an integrated crawler track that will open the track when driven out. Nichols, 1 mastershifter N. of Eng. Official responsible for the working of a seam during the third (night) shift of the day. Trist master station A position in the ventilation circuit of a mine specially chosen for the regular and accurate estimation of the total quantity of air circulating. Spalding mat a. An accumulation of broken mine timbers, rock, earth, etc., coincident with the caving system of mining. As the ore is extracted, the mat gradually settles and forms the roof of the working levels, slopes, etc. b. Lusterless or dull surface in a metal, produced by a method of finishing. Standard, 2 1922

match The part of a detonator that is most easily ignited. Mason materials flowsheet A flowsheet principally concerned with solid materials. See also: operational capacities materials handling The art and science involving movement, packaging, and storage of substances in any form. materials lock An air lock through which materials are passed into or out of a pneumatic caisson or a shaft being driven under air pressure. See also: manlock Hammond Mathewson's device An apparatus for separating matte and slag at lead-silver blast furnaces where matte is of secondary importance. Fay matildite A hexagonal mineral, AgBiS2 ; forms prismatic crystals; sp gr, 6.9 . Syn: schapbachite; plenargyrite. matlockite A tetragonal mineral, 2[PbFCl] ; basal cleavage; an alteration of galena or lead-bearing slags. mat pack Small pack of timber consisting of a number of timbers laid side by side to form a solid mass 2 to 2-1/2 ft square by 4 to 6 in thick (approx. 0.7 m square by 10 to 15 cm thick). Holes are drilled edgeways through the mat, and wires are threaded through to hold it together. Mats are transported underground and built up to form very effective supports. Spalding matraite A trigonal mineral, ZnS ; trimorphous with sphalerite and wurtzite. 1923

matrix a. The nonvaluable minerals in an ore; the gangue. b. The rock material in which a fossil, crystal, or mineral is embedded. Syn: groundmass c. A local term for the phosphatebearing gravel in the land-pebble deposits of Florida. AGI d. The metal in which the diamonds inset in the crown of a bit are embedded. Long e. The material that forms a cushion or binder in the construction of pavement. f. The finer-grained material between the larger particles of a rock or the material surrounding a fossil or mineral. BS, 11 g. The principal phase or aggregate in which another constituent is embedded. ASM, 1 h. In electroforming, a form used as a cathode. ASM, 1 matrix metal The continuous phase of a polyphase alloy or mechanical mixture; the physically continuous metallic constituent in which separate particles of another constituent are embedded. ASTM matrosite A microscopical constituent of torbanite; opaque, black mass forming its groundmass. CF: gelosite; humosite; retinosite. Tomkeieff matte A metallic sulfide mixture made by melting the roasted product in smelting sulfide ores of copper, lead, and nickel. ASM, 1 matte fall Weight of matte expressed as a percentage of the total charge. Newton, 1 matte smelting The smelting of copper-bearing materials, usually in a reverberatory furnace. The valuable product is a liquid, copper-iron sulfide called matte. Kirk matting The process of smelting sulfide ores into matte. Weed, 2 mattock a. A miner's pickax. Fay b. An implement that combines the features of an adz, ax, and pick, and is used for digging, grubbing, and chopping. Webster 3rd 1924

Matura diamond Colorless to faintly smoky gem-quality zircon from the Matara (Matura) district of Sri Lanka; any smokiness is removable by heating. mature a. Pertaining to the stage of maturity of the cycle of erosion; esp. said of a topography or region having undergone maximum development and accentuation of form; or of a stream (and its valley) with a fully developed profile of equilibrium; or of a coast that is relatively stable. AGI b. Said of a clastic sediment that (1) has been differentiated or evolved from its parent rock by processes acting over a long time and with a high intensity and (2) is characterized by stable minerals (such as quartz), deficiency of the more mobile oxides (such as soda), absence of weatherable material (such as clay), and well-sorted but subangular to angular grains. Example: a clay-free mature sandstone on a beach. AGI maturity a. A stage in the development of a coast that is characterized by straightening of the shoreline by bridging of bays and cutting back of headlands so as to produce a smooth, regular shoreline consisting of sweeping curves; and, eventually, retrogradation of the shore beyond the bayheads so that it lies against the mainland as a line of eroded cliffs throughout its course. AGI b. The extent to which a clastic sediment texturally and compositionally approaches the ultimate end product to which it is driven by the formative processes that operate upon it. AGI c. The stage in the development of a stream at which it has reached its maximum efficiency, having attained a profile of equilibrium and a velocity that is just sufficient to carry the sediment delivered to it by tributaries. AGI d. The second of the three principal stages of the cycle of erosion in the topographic development of a landscape or region, intermediate between youth and old age (or following adolescence), lasting through the period of greatest diversity of form or maximum topographic differentiation, during which nearly all the gradation resulting from operation of existing agents has been accomplished. AGI maturity index A measure of the progress of a clastic sediment in the direction of chemical or mineralogic stability; e.g., a high ratio of alumina-soda, of quartz-feldspar, or of quartz + chert-feldspar + rock fragments indicates a highly mature sediment. AGI maucherite A tetragonal mineral, Ni11 As8 ; forms tabular crystals; occurs in nickel-cobalt-nativesilver ore deposits. Syn: placodine; temiskamite. 1925

Mawco cutter loader A cutter loader similar to an Anderton shearer except that the drum is replaced by a frame jib 42 in (107 cm) high and 20 in (51 cm) deep. The machine travels on an armored flexible conveyor at a speed of about 4-1/2 ft/min (1.4 m/min). It cuts a 20-in (51-cm) web on the cutting run, and the plow deflector loads the cut coal onto the conveyor. On the reverse run, the deflector loads all the loose coal left on the track, and the conveyor is snaked over behind the machine. The loader is suitable for mediumthickness seams, and the yield of large coal is good. Nelson maximum and minimum densities In soil tests, the maximum density is found by compacting soil with a Kango hammer; the minimum density is measured by pouring soil into a container of known capacity. This test is useful for determining the relative density of sands, by comparison with field tests. Hammond maximum angle of inclination The maximum angle at which a conveyor may be inclined and still deliver a predetermined quantity of bulk material within a given time. As the maximum angle is approached, the rate of handling of bulk material is usually decreased. maximum belt slope The slope beyond which the material on a conveyor tends to roll downhill. The maximum slope on which a conveyor can operate depends on (1) the material carried, (2) the loading or feeding efficiency, (3) the size and type of belt, and (4) the environment. In general, in the case of run-of-mine coal and ore, belt conveyors can operate up to about 18 degrees . If the material conveyed contains large lumps, spillage may result if the belt is too narrow. Nelson maximum belt tension The total of the starting and operating tensions. In the average conveyor this is considered to be the same as the tight side tension. maximum carbon dioxide content The recommended maximum allowable concentration of carbon dioxide in mine air is 0.5%. Hartman, 1 maximum charge weight per delay

1926

The maximum quantity of explosive charge detonated on one interval (delay) within a blast. The charge detonated within any 8-ms interval over the entire duration of the blast. maximum demand Upper limit of electric power that may be drawn at any time from the mains without penalty, as agreed by contract. Pryor, 3 maximum density See: maximum unit weight maximum dry density The dry density obtained by the compaction of soil at its optimum moisture content. Hammond maximum microcline Microcline with the most complete ordering possible of aluminum and silicon ions in the tetrahedral sites and the smallest angle for beta (maximum triclinicity). CF: mesomicrocline maximum operating belt tension The tension in the carrying run necessary to maintain the normal operating speed of a loaded belt. maximum per delay The maximum vibration at distant points is that which has been generated by the greatest amount of explosive fired at any one instant. Leet, 2 maximum-pressure arch See: pressure arch theory maximum-pressure gage An instrument for registering the maximum pressure occurring during an explosion at the point where the instrument is located. Rice, 2 maximum subsidence

1927

The maximum amount of subsidence in a subsidence basin. The value of maximum subsidence for a given seam thickness depends on the underground geometry and the thickness and character of the overburden. See also: subsidence factor maximum unit weight The dry unit weight defined by the peak of a compaction curve. Syn: maximum density Maxton screen A screening machine of the trommel class, rotating on rollers that support the tube. There are radial elevating ribs to prevent wear of screen cloth and to elevate the oversize. Unscreened material is delivered on the inside screen surface, undersize passes through, and oversize is elevated and discharged into a separate launder. Liddell maxwell The cgs (centimeter-gram-second) unit of magnetic flux. One maxwell = 10 flux through 1 cm2 normal to a field of magnetic induction of 1 Gs. AGI

-8

Wb, or the

Maxwell's rule A law stating that every part of an electric circuit is acted upon by a force tending to move it in such a direction as to enclose the maximum amount of magnetic flux. CTD Mayari iron Pig iron made from Cuban ores that contain vanadium and titanium, or pig iron made to duplicate the Cuban iron. Brady, 1 mayenite An isometric mineral, Ca12 Al14 O33 ; occurs in metamorphosed marly limestone; an important constituent of portland cement clinker. mboziite A potassian variety of taramite amphibole. McGinty Three sheaves over which a rope is passed so as to take a course somewhat like that of the letter M. The resulting friction causes the rope to slide with difficulty. It is used for lowering loaded cars from the face to the mouth of a room on a steep roadway. Zern 1928

mcgovernite A trigonal mineral, (Mn,Mg,Zn)22 (AsO3 )(AsO4 )3 (SiO4 )3 (OH)20 ; reddish-bronze; forms granular masses with perfect basal cleavage. Also spelled macgovernite. McKelvey diagram A graphical classification of mineral resources according to economic viability and certainty of existence. Used by the U.S. Bureau of Mines and the U.S. Geological Survey in their definitions of mineral resources and reserves, USGS Circular 831. Named after Vincent E. McKelvey, ninth director of the U.S. Geological Survey. Barton McLuckie gas detector This nonautomatic detector, or portable air analysis apparatus, can be used underground, or samples of air can be brought out of the mine in small rubber bladders and analyzed at the surface. This apparatus depends for its action on the fact that when methane is burned in air (oxygen) a definite chemical action takes place. When the resulting steam condenses to water there is a reduction in pressure and in the McLuckie detector this reduction of pressure, which is proportionate to the methane present, is indicated by the height of the liquid in one limb of the U-tube which rises up the side of the scale: the scale is graduated from 0% to 3% in steps of 0.1%. Cooper McNally-Carpenter centrifuge A fine-coal dewatering machine consisting of a conical rotating element with a vertical axis, built up of three rows of perforated stainless steel screen plates or stainless steel wedge or round-wire sections cut and rolled to conform to the surface of the cone. Wet feed is deposited by gravity into the top of the cone-shaped dryer onto a distributing disk that throws the material by centrifugal force onto the stepped screen or basket. The rapid circular movement of the basket forces the water through the screen, while the coal moves toward the bottom. Peripheral velocity and centrifugal force become greater for each particle, breaking down the surface tension of water film on each piece, increasing drying action directly in ratio to the cone circumference and peripheral speed. The most effective drying area is at the bottom of the cone just before the material is discharged from the machine. See also: dewatering Kentucky; Mitchell McNally-Norton jig In this jig, raw coal is conveyed to a wash box through sluices. Air pulsations are transmitted through valves to water in a compartment adjacent to the washing bed, causing the water in the wash box to rise. Pulsating water causes the incoming fuel to be loosely suspended in the water and permits heavier refuse to sink to the screen plate while suspended coal spills over into the second compartment. In the second 1929

compartment the process is repeated with the remaining refuse sinking to the screen and clean coal discharging to the dewatering screens. Kentucky McNally-Vissac dryer A convection dryer of the forced-draft type. The heat source is a coal-fired furnace. It consists essentially of a declined reciprocating screen over which the coal travels. Two balanced tandem decks are used. They are suspended from the supporting structure by inclined flexible hangers and actuated in opposition through flexible pitmans from a common eccentric shaft. The removal of moisture is accomplished by passing hot furnace gases, tempered with cold air, downward through the bed of coal as it travels along the screen. An induced-draft fan at the exhaust end provides the motive force for the gases. See also: thermal drying Mitchell McNamara clamp A drill-rod safety clamp somewhat similar to a Wommer's safety clamp. Long M-design core barrel Standard-design, double-tube, swivel-type core barrel made in sizes to be used with appropriate standard ranges of diamond-drill fittings. Its distinguishing features are that a 2-1/2 degrees taper core lifter is carried inside a short tubular sleeve (called a lifter case) coupled to the bottom end of the inner tube, and that the lifter case extends downward inside the bit shank to within a very short distance behind the face of the core bit. Long M-discontinuity See: Mohorovicic discontinuity M.E. 6 exploder An exploder approved for firing six shots simultaneously in British coal mines. It contains a 67-1/2-V high-tension dry battery, used to charge a 150-mu F condenser, which in turn is discharged through the shotfiring circuit by a firing key. The test circuit and an ohmmeter are incorporated in the exploder, thc ohmmeter pointer moving over a scale to indicate whether or not the external circuit is in order. A pushbutton disconnects the test circuit from the external circuit and makes connection with the firing circuit. See also: blasting machine meadow ore See: bog iron; bog iron ore; limonite. meager feel 1930

Moistureless; dry and rough to the touch, such as chalk and magnesite. Nelson mean An arithmetic average of a series of values; esp. arithmetic mean. CF: mode mean birefringence The numeral that represents the average between the greatest strength of double refraction and the least strength of double refraction possessed by a species or variety. The refractive index of sphene, e.g., is 1.885 to 1.990 and 1.915 to 2.050; hence the birefringence ranges from 0.105 to 0.135. The average, or mean, is 0.120. Syn: refractive index mean calorie One-hundredth of the heat required to raise 1 g of water from 0 degrees C to 100 degrees C. Newton, 1 mean depth The cross-sectional area of a stream divided by its width at the surface. AGI meander a. One of a series of regular, freely developing sinuous curves, bends, or loops in the course of a stream. It is produced by a mature stream swinging from side to side as it flows across its floodplain or shifts its course laterally toward the convex side of an original curve. Etymol: Greek maiandros, from Maiandros River in western Asia Minor (now known as Menderes River in SW Turkey), proverbial for its windings. AGI b. To wind or turn in a sinuous or intricate course; to form a meander. AGI meander belt That part of a floodplain between two lines tangent to the outer bends of all the meanders. It is the zone within which channel migration occurs, as indicated by abandoned channels, accretion topography, and oxbow lakes. meander line A line run in a survey of a mining claim bordering on a stream or other body of water, not as a boundary of the tract surveyed, but for the purpose of defining the sinuosities of the bank or shore of the water, and as a means of ascertaining the quantity of land within the surveyed area. Ricketts 1931

mean effective pressure In an air compressor, the equivalent average pressure exerted by the piston throughout a stroke. Lewis mean radiant temperature (mrt) Single temperature of all enclosing surfaces that would result in the same heat emission as the same surface with various different temperatures. Strock, 2 mean refractive index a. The index of refraction measured for the D line of sodium. b. For uniaxial crystals: (2nomega +nepsilon )/3. For biaxial crystals: (nalpha +nbeta +ngamma )/3. mean size The weighted average particle size of any sample, batch, or consignment of particulate material. BS, 5 mean sphere depth The uniform depth to which water would cover the Earth if the solid surface were smoothed off and parallel to the surface of the geoid. Generally accepted as a depth of 2,440 m. Hy mean stress a. In fatigue testing, the algebraic mean of the maximum and minimum stress in one cycle. Also called the steady-stress component. ASM, 1 b. In any multiaxial stress system, the algebraic mean of three principal stresses; more correctly called mean normal stress. ASM, 1 measured depth See: measured drilling depth measured drilling depth The apparent depth of a borehole as measured along the longitudinal axis of the borehole. The measured drilling depth is always equal to the unoverlapped drilled footage in a borehole. Also called measured depth. Sometimes abbreviated md. Long measured resources 1932

Resources from which the quantity is computed from dimensions revealed in outcrops, trenches, workings, or drill holes; grade and/or quality are computed from the results of detailed sampling. The sites for inspection, sampling, and measurement are spaced so closely and the geologic character is so well defined that size, shape, depth, and mineral content of the resource are well established. See also: reserves measurement The finding of the number of units of measure in a line, area, space or volume, period of time, etc. Jones, 2 measurement of concentration Gr. Brit. At the National Coal Board collieries, in order to assess the degree of concentration, certain basic data are collected, involving the pithead output, length of main haulage roads, and length of coalface in production. See also: face concentration; geographical concentration; overall concentration. Nelson measures A group or series of sedimentary rocks having some characteristic in common; specif. coal measures. The term apparently refers to the old practice of designating the different seams of a coalfield by its measure or thickness. AGI measures head A heading or drift made in various strata. Fay measuring chain A surveyor's chain, containing 100 links of 7.92 in (20.12 cm) each. measuring chute A bin installed adjacent to the shaft bottom in skip winding. The capacity of the chute is equal to that of the skip used, ranging from 4 to 10 st (3.6 to 9.1 t). Bin-feeding arrangements differ but may be by a steelplate conveyor from a surge bunker that in turn receives the ore or coal from the mine cars or a trunk conveyor. A measuring chute ensures a quick and correct loading of skips without spillage. Immediately the skip is positioned in line, the measuring chute bottom door opens and material is discharged into the skip. See also: pocket Nelson measuring day The day when face or other work is measured and recorded for assessing wages. Nelson 1933

measuring element In flotation, that portion of the feedback elements that converts the signal from the primary detecting element to a form compatible with the reference input. Fuerstenau measuring pocket Storage space near an entry from underground workings to a hoisting shaft; laid out so as to deliver a measured volume into a hoisting skip and to be refilled before the skip returns empty. Pryor, 3 measuring tape A graduated tape, steel or linen, usually in 50-ft or 100-ft (15-m or 30.4-m) lengths; used by engineers, builders, surveyors, etc. Crispin measuring weir A device for measuring the flow of water. It generally consists of a rectangular, trapezoidal, triangular, or other shaped notch in a thin plate in a vertical plane through which the water flows. The weir head is an index of the rate of flow. See also: notch mechanical advantage Ratio between the resistance or load raised by a machine, and the applied force. Mechanical advantage divided by velocity ratio gives the efficiency of the machine. Hammond mechanical air machine A flotation machine that utilizes pulp-body concentration by the agitation froth method and bubble-column action by pneumatic and cascade means. Taggart, 1 mechanical analysis Determination of the particle-size distribution of a soil, sediment, or rock by screening, sieving, or other means of mechanical separation; the quantitative expression of the sizefrequency distribution of particles in granular, fragmental, or powdered material. It is usually expressed in percentage by weight (and sometimes by number or count) of particles within specific size limits. See also: particle-size analysis AGI mechanical classifier One of the machines, such as the Dorr classifier, that are commonly used to classify a ball-mill or rod-mill discharge into finished product and oversize. Newton, 1 1934

mechanical clay A clay formed from the products of the abrasion of rocks. mechanical cleaning The removal of impurities by mechanical units as compared with hand picking. Broadly, mechanical cleaning may be subdivided into dry cleaning and wet cleaning. Mitchell; Nelson mechanical efficiency The ratio of the air-indicated horsepower to the indicated horsepower in a power cylinder, in the case of compression driven by steam or internal-combustion engines, and to the brake horsepower delivered to the shaft in the case of a power-driven machine. Lewis mechanical equivalent of heat Amount of mechanical energy that can be transformed into a single heat unit; the equivalent of 778 ft.lbf/Btu (1,000 N.m/kJ). Hammond mechanical extensometer An appliance for measuring strain; often used in roof control investigations. It employs a micrometer dial gage actuated through a lever giving initial magnification of the movement. See also: acoustic-strain gage; electrical resistance strain gage. Nelson mechanical flotation cell A cell in which the solids-water pulp feed is kept agitated, and is circulated by means of an impeller mounted at the bottom of a vertical shaft. The rotating impeller creates vacuum enough to draw air down the standpipe surrounding the impeller shaft, and the impeller disperses the air throughout the pulp in the form of small bubbles. The flotable minerals are carried upward by the bubbles and eventually collect in the froth above the pulp in the machine. Automatic scrapers remove the mineral-laden froth that contains the concentrate, and after the values have been removed, the barren pulp containing the tailing flows out of the cell. Newton, 1 mechanical loader A power machine for loading materials. See also: loader. mechanical mixture 1935

A composition of two or more substances, each remaining distinct, and generally capable of separation by mechanical means. Standard, 2 mechanical properties Of metals: the elastic limit, elongation, fatigue range, hardness, maximum stress, reduction in area, shock resistance, and yield point. Pryor, 3 mechanical puddler A wrought-iron (rocking) furnace in which puddling is done by mechanical motion instead of by hand. Mersereau, 2 mechanical puddling See: mechanical puddler mechanical rabble A rabble worked by machinery. See also: rabble mechanical rammer A machine embodying a weight that is lifted and dropped upon the material being rammed. See also: power rammer mechanical sampling Mechanical sampling systematically removes a portion of the stream of material for a sample. Mechanical sampling is widely used in cone preparation plants and concentrators where large quantities of materials are to be sampled, while hand sampling is used for smaller amounts. CF: hand sampling mechanical sediment Sediment that has been brought to its places of deposition as separate particles by mechanical means. Water, wind, and ice are the agents commonly involved; the resulting rocks are conglomerate, sandstone, siltstone, shale, and certain limestones. Stokes mechanical set Bits produced by the various means in which diamonds are set in a bit mold into which a cast or powder metal is placed, embedding the diamonds and forming the bit crown, as opposed to handsetting. Also, the act or process of producing diamond bits in such a manner. Also called cast set; machine set; sinter set. CF: handset 1936

mechanical-set bit A diamond bit produced by mechanical methods as opposed to handsetting methods. See also: mechanical set mechanical shovel A loader limited to level or only slightly graded drivages. The machine operates a shovel in front of it and pushes itself forward; when full, the shovel is swung over the machine and delivers into a mine car or tub behind. It will shunt, pull, and push its own cars, delivering them into a shunt or passby when full. See also: shovel loader mechanical stabilization Mixing two or more poorly graded soils to obtain a well-graded one. Nelson mechanical weathering The process of weathering by which frost action, salt-crystal growth, absorption of water, and other physical processes break down a rock to fragments, involving no chemical change. CF: chemical weathering Syn: disintegration mechanical working Subjecting metal to pressure exerted by rolls, presses, or hammers, to change its form or affect the structure, and therefore the physical properties. Rolfe mechanical yielding prop A steel prop in which yield is controlled by friction between two sliding surfaces or telescopic tubes. Although crude when compared with the hydraulic prop, the friction yield prop is very robust, is cheap, and requires little maintenance. Nelson mechanics The branch of physics that treats of the phenomena caused by the action of forces on material bodies. It is subdivided into statics, dynamics, or kinetics; or into the mechanics of rigid bodies and hydromechanics (including hydrostatics and hydrodynamics). Standard, 2 mechanization Essentially, the introduction of power machines to replace manual labor. In coal mining, it may denote the introduction of conventional machine mining to replace hand mining, or continuous mining to replace conventional machine mining. Nelson 1937

mechanization engineer Usually a qualified mining engineer with first-hand experience and knowledge of the various mining machines and the physical conditions most suitable for them. In general, the National Coal Board, Great Britain, appoints a mechanization engineer for each group of collieries. Nelson mechanization scheme A plan or project to convert a handmining or a conventional machine mining face to mechanized mining; i.e., the use of machines that either load prepared coal or cut and load coal simultaneously (cutter loaders). The scheme may also include the introduction of locomotives, skip winding, etc. Nelson mechanized Term descriptive of a mine that has a high percentage of machinery for all steps of mining and handling mineral product, from the face to the mine working place, and on to the tipple or treatment plant. BCI mechanized heading development A pillar method of working suitable for seams 4 ft (1.2 m) and over in thickness. Three or more narrow headings are driven rapidly with machines at about 30-yd (10-m) centers with crosscuts for ventilation. The headings are 10 ft (3 m) or more wide and 5 to 6 ft (approx. 2 m) high or seam thickness. Upon reaching the boundary, the pillars formed by the headings are extracted, again with machines, on the retreat. This method is favored in the United States and the heading work is quite as productive, if not more so, than pillar working. See also: entry; longwall retreating. Nelson mechanized output The coal produced by all coal face machinery that either loads prepared coal or cuts and loads coal simultaneously. Also includes all coal obtained by hand filling on faces where an armored flexible conveyor is used on a prop-free front. Nelson Meco-Moore cutter loader A heavy 120-hp (89.5-kW) cutter loader. The first Meco-Moore was used in a Lancashire, England, colliery in 1934. See also: A Nelson medfordite See: moss agate 1938

median diameter An expression of the average particle size of a sediment or rock, obtained graphically by locating the diameter associated with the midpoint of the particle-size distribution; the middlemost diameter that is larger than 50% of the diameters in the distribution and smaller than the other 50%. AGI medical lock An air chamber comprising steel cylinder 18 ft (5.5 m) long and about 6 ft (1.8 m) in diameter, which has airtight doors at one end and is closed at the other. It is used for immediate treatment of sufferers from caisson disease. Hammond Medina emerald Green glass emerald simulant. mediosilicic A term proposed by Clarke (1908) to replace intermediate. CF: subsilicic; persilicic. See also: intermediate Mediterranean suite A major group of igneous rocks, characterized by high potassium content. This suite was so named because of the predominance of potassium-rich lavas around the Mediterranean Sea; specif. those of Vesuvius and Stromboli. CF: Atlantic suite; Pacific suite. AGI medium Any suspension of medium solids in water. BS, 5 medium band A field term that, in accordance with an arbitrary scale established for use in describing banded coal, denotes a vitrain band ranging in thickness from approx. 1/12 to 1/5 in (2 to 5 mm). AGI medium draining screen A screen for draining the separating medium from dense-medium bath products. BS, 5 medium-grained 1939

a. Said of an igneous rock, and of its texture, in which the individual crystals have an average diameter in the range of 0.04 to 0.2 in (1 to 5 mm). AGI b. Said of a sediment or sedimentary rock, and of its texture, in which the individual particles have an average diameter in the range of 1/16 to 2 mm (62 to 2,000 mu m, or sand size). CF: coarsegrained; fine-grained. AGI medium-inclined Said of deposits and coal seams with a dip of 25 degrees to 40 degrees . Stoces medium pressure When applied to valves and fittings, means suitable for a working pressure of 125 to 175 psi (860 to 1,200 kPa). Strock, 1 medium-recovery screen A composite screen for draining and spraying the product from a dense-medium bath to remove adherent medium solids. BS, 5 medium-round nose A diamond bit the cross-sectional outline of which is partially rounded but not as fully rounded as a double-round nose bit. Syn: half-round nose; modified-round nose. Long medium solids The solid component of a dense-medium suspension. BS, 5 medium-solids preparation Any purification or grinding of the raw dense-medium solids to make them suitable for use. BS, 5 medium-solids recovery See: dense-medium recovery medium-solids recovery plant The equipment used to remove adherent medium solids from a product from a densemedium bath (after drainage of surplus medium), usually by spraying, and to remove contaminating coal and clay from these medium solids. BS, 5 medium-stone bit 1940

A bit with diamonds ranging from 8 to 40 per carat in size. Long medium-thickness seam In general, a coal seam over 2 ft (0.6 m) and up to 4 ft (1.2 m) in thickness. Nelson medium-volatile bituminous coal The rank of coal, within the bituminous class of Classification D 388, such that, on the dry and mineral-matter-free basis, the volatile matter content of the coal is greater than 22% but equal to or less than 31% (or the fixed carbon content is equal to or greater than 69% but less than 78%), and the coal commonly agglomerates. CF: bituminous coal ASTM medium voltage In coal mining, voltage from 661 to 1,000 V. CF: high voltage; low voltage. Federal Mine Safety medmontite A mixture of chrysocolla and mica. See also: cupromontmorillonite meehanite High-duty cast iron produced by ladle addition of calcium silicide. Pryor, 3 meerschaum See: sepiolite meet a. Eng. To keep pace with; e.g., to keep sufficient supply of coal at the pit bottom to supply the winding engine. Fay b. To come together exactly, as in survey lines from opposite directions. Fay meeting a. A siding or bypass on underground roads. Fay b. Newc. The place at middle-depth of a shaft, slope, or plane, where ascending and descending cars pass each other. Fay meeting post

1941

A vertical timber at the outer edge of each of a pair of lock gates, mitered so that the gates fit tightly when closed. Hammond megaa. A prefix meaning large. As a prefix to petrological and other geologic terms, it signifies parts or properties that are recognizable by the unaided eye. Opposite of micro-. Stokes b. A combining form meaning 1 million times; e.g., megavolt for 1 million volts. AGI megabar A unit of pressure equal to 1 Mdyn/cm2 . Standard, 2 megacycle A unit of 1 million cycles. CTD megaphenocryst A phenocryst that is visible to the unaided eye. AGI megascopic Said of an object or phenomenon, or of its characteristics, that can be observed with the unaided eye or with a hand lens. Syn: macroscopic CF: microscopic megaseismic region The most disturbed earthquake area. Schieferdecker megaspore Female spore; part of the reproduction organs of many coal measures plants. See also: spore Megator A displacement type of pump operating on the eccentric principle. Mason megger An electrical measuring instrument comprising a hand-operated generator equipped with a governor, a moving measuring system consisting of a voltage, and a current coil so disposed that the deflection of the moving system is proportional to the ratio of voltage 1942

to current. Used to measure insulation resistance and resistance to ground. It has been used to some extent in electrical prospecting. AGI Meigen's reaction A test to distinguish calcite from aragonite. After boiling for 20 min in a cobalt nitrate solution, aragonite becomes lilac, the color showing in thin section, while calcite and dolomite become pale blue, the color not showing in thin section. meionite A tetragonal mineral, 3CaAl2 Si2 O8 .CaCO3 ; scapolite group; forms a series with marialite. meizoseismal Of or pertaining to the maximum destructive force of an earthquake. Standard, 2 meizoseismal area The most disturbed area within the innermost isoseismal line. Schieferdecker meizoseismal curve A curved line connecting the points of the maximum destructive energy of an earthquake shock around its epicenter. Standard, 2 melaA prefix meaning dark-colored. AGI melaconite An earthy variety of tenorite. See also: black copper ore; tenorite. melanasphalt An early name for albertite. Tomkeieff melanchyme A bituminous substance found in masses in the brown coal of Zweifelsruth, Bohemia, former Czechoslovakia. That part of this substance that is soluble in alcohol is termed rochlederite, the residue melanellite. Also spelled melanchym. Fay 1943

melanellite That portion of melanchyme that is insoluble in alcohol; it is black and gelatinous. Fay melange a. Diamonds of mixed sizes. Hess b. An assortment of mixed sizes of diamonds weighing more than 1/4 carat; e.g., larger than those of a melee. c. A body of rock mappable at a scale of 1:24,000 or smaller, characterized by a lack of internal continuity of contacts or strata and by the inclusion of fragments and blocks of all sizes, both exotic and native, embedded in a fragmental matrix of finer-grained material. Neither matrix composition and fabric nor genesis is significant for the definition. melanic See: melanocratic melanite A titanian variety of andradite. Syn: black andradite garnet; pyreneite. melanocratic Applied to dark-colored rocks, esp. igneous rocks, containing between 60% and 100% dark minerals; i.e., rocks, the color index of which is between 60 and 100. CF: hypermelanic; leucocratic; mesocratic. AGI melanostibite A trigonal mineral, Mn2 SbFeO6 . Originally named melanostibian. melanotekite An orthorhombic mineral, Pb2 Fe2 Si2 O9 ; forms a series with kentrolite. melanovanadite A triclinic mineral, CaV4 O10 .5H2 O ; a natural vanadium bronze with perfect prismatic cleavage; at Cerro de Pasco, Peru, and on the Colorado Plateau. melanterite a. A monoclinic mineral, FeSO4 .7H2 O ; green; tastes slightly sweet, astringent, and metallic; from the decomposition of pyrite. b. The mineral group bieberite, boothite, mallardite, melanterite, and zincmelanterite. Syn: copperas; green vitriol; iron vitriol. 1944

melatope The narrowest part of an isogyre in an interference figure representing the point of emergence of an optic axis. CF: interference figure melee a. A collective term for small round faceted diamonds, such as those mounted in jewelry. The term is sometimes applied to colored stones of the same size and shape as the diamonds. AGI b. A small diamond cut from a fragment of a larger size. AGI c. In diamond classification, a term for small round-cut diamonds weighing more than 1/4 carat. CF: melange melilite a. A tetragonal mineral in the series akermanite, Ca2 MgSi2 O7 -gehlinite, Ca2 Al(AlSi)O7 . b. The mineral group akermanite, gehlenite, hardystonite, and melilite. Jeffreyite, leucophanite, and meliphanite are structurally similar. Also spelled mellilite. melilitite A generally olivine-free extrusive rock composed of melilite and clinopyroxene (or other mafic mineral) usually comprising more than 90% of the rock, with minor amounts of feldspathoids and sometimes plagioclase. AGI melinite a. A high explosive similar to lyddite; said to be chiefly picric acid. Webster 2nd b. A species of soft, unctuous clay, common in Bavaria, and probably identical with bole. Standard, 2 meliphanite A tetragonal mineral, (Ca,Na)2 Be(Si,Al)2 (O,OH,F)7 ; structurally similar to the melilites. Also spelled meliphane. Syn: gugiaite melle Small cut diamonds, usually about one-eighth carat. Generally refers to stones used in jewelry. Hess mellilite See: melilite 1945

mellite A tetragonal mineral, Al2 [C6 (COO)6 ].16H2 O; resinous; honey yellow; forms nodules in brown coal. Also spelled melinite, mellilite. (Not melite.) Syn: honey stone mellorite A silicate of ferric iron, calcium, etc., approaching garnet in composition, but with optical properties similar to those of an orthorhombic pyroxene. Formed by the action of basic slag on silica brick in a steel furnace. Spencer, 2; AGI mellow amber See: gedanite melonite a. A trigonal mineral, NiTe2 ; forms a series with merenskyite; one perfect cleavage; metallic reddish white; soft; sp gr, 7.3. b. The mineral group berndtite, kitkaite, melonite, merenskyite, and moncheite. Syn: tellurnickel melteigite A dark-colored plutonic rock that is part of the ijolite series and contains nepheline and 60% to 90% mafic minerals, esp. green pyroxene. The name is from Melteig farm, Fen complex, Norway. AGI melting hole The opening in the floor to a furnace in a melting house. Mersereau, 2 melting house The building in which crucible furnaces for steel making are located. Mersereau, 2 melting point That temperature at which a single, pure solid changes phase to a liquid or to a liquid plus another solid phase, upon the addition of heat at a specific pressure. Unless otherwise specified, melting points are usually stated in terms of 1 kPa. The term can also be used for the isothermal melting of certain mixtures, such as eutectic mixtures. Erroneously used also to refer to the temperature at which some appreciable but unspecified amount of liquid develops in a complex solid mixture that possesses a melting range; e.g., the melting point of granite. Abbrev.: mp or MP. AGI 1946

melting pot A crucible. Standard, 2 melting shop Open-hearth plant. Newton, 1 melting zone The hottest part of a furnace, where melting takes place. Mersereau, 2 member A division of a formation, generally of distinct lithologic character and of only local extent. membrane filter See: molecular filter sampler membrane theory An advanced theory of design for thin shells, based on the premise that a shell cannot resist bending because it deflects. The only stresses that exist, therefore, in any section are shear stress and direct compression or tension. Hammond menaccanite a. A variety of ilmenite found as sand at Menaccan, Cornwall, Eng. b. A black, magnetic sand from Cornwall, England, from which the element, titanium, was first isolated. Also spelled menachanite; manaccanite; menachite. Hess mend Eng. To load, or reload, trams at the gate ends out of smaller trams used only in the working faces of thin seams. mendipite An orthorhombic mineral, Pb3 Cl2 O2 ; white; in the Mendip Hills, United Kingdom. mendozite A monoclinic mineral, NaAl(SO4 )2 .11H2 O . See also: soda alum 1947

meneghinite An orthorhombic mineral, Pb13 CuSb7 S24 ; forms slender prismatic blackish lead-gray crystals. Menevian European stage: Middle Cambrian (above Solvan, below Maentwrogian). AGI menilite A concretionary, opaque, dull, grayish variety of opal. Syn: liver opal Fay meniscus a. The curved top surface of a liquid column. It is concave upwards when the containing walls are wetted by some liquid (such as water in a vertical glass tube) and convex upwards when wetted with other liquids (such as mercury in a vertical glass tube). Webster 3rd b. A concavoconvex lens; esp., one of true crescent-shaped cross section. Webster 3rd men on! Scot. A brief expression to indicate that workers are on the cage to be raised, or lowered, in a shaft. Fay Menzies cone separator Consists of a 60 degrees cone with a short cylindrical top section. It is provided with a stirring shaft, located in its vertical axis, carrying several sets of horizontal arms with rings of nozzles projecting through the sides of the cone for the admission, at several horizons, of the required water currents. At the base of the cone, a classifier column several feet long is fitted, through which refuse discharges continuously to an inclined refuse conveyor. Water is supplied by a centrifugal pump. See also: cone classifier mephitic air a. Carbon dioxide. Webster 3rd b. Air exhausted of oxygen and containing chiefly nitrogen. Webster 3rd mephitic gas See: mephitic air mephitis 1948

A noxious exhalation caused by the decomposition of organic remains; applied also to gases emanating from deep sources, such as mines, caves, and volcanic regions. Standard, 2 merchant A metal merchant, as distinct from a producer's agent or broker, often acts as a principal, buying metal or concentrate from producers and others and selling it to others. The merchant will often hold metal on personal account while waiting for a buyer. Wolff merchant iron Iron in the common bar form, which is convenient for the market. Also called merchant bar. Standard, 2 mercurial horn ore See: calomel mercury a. A liquid mineral, (trigonal below -38.87 degrees C); metallic silver to tin white; sp gr, 13.6; occurs as minute droplets in cinnabar and in some hot-spring deposits; amalgamates with many metals. b. Symbol: Hg. Rarely occurs free in nature. Chief ore is cinnabar, HgS . Used in laboratory work for making thermometers, barometers, diffusion pumps, mercury-vapor lamps, advertising signs, and pesticides. Mercury is a virulent poison and is readily absorbed through the respiratory tract, gastrointestinal tract, or unbroken skin. Handbook of Chemistry and Physics, 3 mercury gatherer A stirring apparatus that causes mercury, which has become floured or mixed with sulfur in amalgamating, to resume the fluid condition, through the agency of mechanical agitation and rubbing. Fay mercury ore Native mercury; same as cinnabar (sulfide). Dana, 3 mercury switch A glass tube employing mercury to establish electrical contact between circuits when the tube is tilted so that the mercury bridges the gap between contacts, and conversely. Strock, 2 1949

mercury-vapor lamp Consists essentially of a sealed glass tube provided with two electrodes and containing a gas. When an electrical potential difference is applied, a current passes and with a suitable gas, light will be emitted. In the case of mercury vapor, this light is of a bluish color and has proven effective in distinguishing dirt from coal. A special starting electrode close to one of the main electrodes initiates the discharge, and a choke coil in series with the lamp serves to limit the current passing, since the resistance tends to fall with increasing current. Mason meroA prefix signifying part or portion. AGI merocrystalline See: hypocrystalline merohedral Any crystal form with fewer faces than the holohedral equivalent for the crystal system. CF: hemihedral; holohedral. See also: tetartohedral meroleims Coalified remains of parts of plants. Tomkeieff merosymmetric Any crystal class with less symmetry than the distribution of points in its lattice. meroxene Biotite with its optic axial plane parallel to its b crystallographic axis. Merrill-Crowe process Removal of gold from pregnant cyanide solution by deoxygenation, followed by precipitation on zinc dust, followed by filtration to recover the resultant auriferous gold slimes. Pryor, 3 Merrill filter A type of plate and frame pressure filter. 1950

merrillite a. High-purity zinc dust used to precipitate gold and silver in the cyanide process. b. See: whitlockite Merrit plate See: bloomery mersey yellow coal See: tasmanite merwinite A monoclinic mineral, Ca3 Mg(SiO4 )2 ; colorless to pale green. mesa An isolated, nearly level landmass standing distinctly above the surrounding country, bounded by abrupt or steeply sloping erosion scarps, and capped by a layer of resistant, nearly horizontal rock (often lava). CF: plateau Mesabi non-Bessemer ore See: natural ore mesa-butte See: butte Mesa Grande tourmaline Fine-quality tourmaline from a pegmatite near Mesa Grande, San Diego County, CA. mesh a. In ventilation, a series of airways that form a closed loop. Roberts, 1 b. The screen number of the finest screen of a specified standard screen scale. c. The number of apertures per unit area of a screen (sieve). mesh aperture

1951

The dimension or dimensions of the aperture in a screen deck, usually with a qualification as to the shape of aperture; e.g., round-hole, square-mesh, and long-slot. BS, 5 mesh fraction That part of a material passing a specified mesh screen and retained by some stated finer mesh. Henderson mesh liberation size The particle size at which substantially all of the valuable minerals are detached from the gangue minerals. Fuerstenau mesh number The designation of size of an abrasive grain, derived from the openings per linear inch in the control sieving screen. Syn: grit number ACSG, 2 mesh of grind Optimum particle size resulting from a specific grinding operation, stated in terms of percentage of material passing (or alternatively being retained on) a given size screen. The mesh of grind is the liberation mesh decided on as correct for commercial treatment of the material. Abbrev., m.o.g. Pryor, 3 mesh structure A structure resembling network or latticework that is found in certain alteration products of minerals. Also called net structure; lattice structure. Standard, 2; Fay mesh texture a. A texture resembling a network, caused by the alteration of certain minerals; e.g., the serpentinization of olivine. Syn: reticulate texture b. An interlacing network of microveinlets of fibrous serpentine enclosing cores of more weakly birefringent cryptocrystalline serpentine in which relict remnants of olivine may survive. Also called net structure; lattice structure. mesoA prefix meaning middle. CF: cata-; meta-. AGI mesocratic 1952

Applied to igneous rocks that are intermediate between leucocratic and melanocratic rocks; they contain 30% to 60% dark minerals. CF: melanocratic; leucocratic. CTD mesocrystalline Said of the texture of a rock intermediate between microcrystalline and macrocrystalline; also, said of a rock with such a texture. AGI mesogene Said of a mineral deposit or enrichment of mingled hypogene and supergene solutions; also, said of such solutions and environment. CF: hypogene; supergene. AGI mesokaites Group name for brown coals. Tomkeieff mesolite A monoclinic mineral, Na2 Ca2 [Al2 Si3 O10 ]3 .8H2 O ; zeolite group; pseudoorthorhombic; in cavities in basalt and andesite, geodes, and hydrothermal veins. Syn: cotton stone; winchellite. mesomicrocline Microcline intermediate in structural state between orthoclase and maximum microcline. Syn: intermediate microcline mesostasis The last-formed interstitial material between the larger mineral grains in an igneous rock or in a microcrystalline groundmass. CF: groundmass mesothermal Said of a hydrothermal mineral deposit formed at considerable depth and in the temperature range of 200 to 300 degrees C. Also, said of that environment. CF: hypothermal deposit; epithermal; leptothermal; telethermal; xenothermal. AGI mesothermal deposit A mineral deposit formed at moderate temperature and pressure, in and along fissures or other openings in rocks, by deposition at intermediate depths, from hydrothermal fluids. Mesothermal deposits are believed to have formed mostly between 175 degrees C and 1953

300 degrees C at depths of 4,000 to 12,000 ft (1,220 to 3,660 m). Many valuable metalliferous deposits of western North America are of this type. Stokes Mesozoic An era of geologic time, from the end of the Paleozoic to the beginning of the Cenozoic, or from about 225 million years to about 65 million years ago. AGI mesozone According to Grubenmann's classification of metamorphic rocks (1904), the intermediate-depth zone of metamorphism, which is characterized by temperatures of 300 to 500 degrees C and moderate hydrostatic pressure and shearing stress. Modern usage stresses temperature-pressure conditions (medium to high metamorphic grade) rather than the likely depth of zone. CF: katazone; epizone. AGI messelite A triclinic mineral, Ca2 (Fe,Mn)(PO4 )2 .2H2 O; fairfieldite group. Syn: neomesselite; parbigite. (Not mesolite.) mestre Port. Mine boss. Hess meta a. In petrology, indicates a metamorphosed protolith. b. In mineralogy, indicates a mineral species that is a dehydration product of another mineral species or is a polymorph. metaA prefix that, when used with the name of a sedimentary or igneous rock, indicates that the rock has been metamorphosed, e.g., metabasalt. CF: cata-; meso-. AGI meta-alunogen A monoclinic mineral, Al4 (SO4 )6 .27H2 O . See also: alunogen meta-anthracite The rank of coal, within the anthracite class of Classification D-388, such that, on the dry and mineral-matter-free basis, the volatile matter content of the coal is equal to or 1954

less than 2% (or the fixed carbon is equal to or greater than 98%), and the coal is nonagglomerating. ASTM meta-argillite An argillite that has been metamorphosed. AGI meta-arkose Arkose that has been welded or recrystallized by metamorphism so that it resembles a granite or a granitized sediment. CF: recomposed granite AGI meta-autunite a. A tetragonal mineral, Ca(UO2 )2 (PO4 )2 .2-6H2 O ; yellow; an alteration product of uraninite and other uranium-bearing minerals. b. The mineral group abernathyite, bassetite, chernikovite, meta-ankoleite, meta-autunite, metaheinrichite, metakahlerite, metakirchheimerite, metalodevite, metanovacekite, metatorbernite, meta-uranocircite, meta-uranospinite, metazeunerite, sodium uranospinite, and uramphite. metabasite A collective term, first used by Finnish geologists, for metamorphosed mafic rock that has lost all traces of its original texture and mineralogy owing to complete recrystallization. AGI metabentonite a. Metamorphosed, altered, or somewhat indurated bentonite; characterized by clay minerals (esp. illite) that no longer have the property of absorbing or adsorbing large quantities of water; nonswelling bentonite, or bentonite that swells no more than do ordinary clays. The term has been applied to certain Ordovician clays of the Appalachian region and upper Mississippi River Valley. See also: potassium bentonite b. A mineral of the montmorillonite group with SiO2 layers in the montmorillonite structure. AGI metabitumite Hard black lustrous variety of hydrocarbon found in proximity of igneous intrusions. Tomkeieff metabolism A term proposed by Barth (1962) for the redistribution of granitizing materials within sediments by mobilization, transfer, and reprecipitation, as opposed to metasomatism involving addition of new materials. AGI 1955

metabolite a. An old term for altered glassy trachyte. b. Iron meteorite with the composition of an octahedrite but lacking Widmaenstatten figures. metaborite An isometric mineral, HBO2 ; in crystalline aggregates in rock salt in Kazakhstan(?). metabrushite See: brushite metachemical metamorphism A term proposed by Dana to describe metamorphism that involves a chemical change in the affected rocks. metacinnabar An isometric mineral, HgS ; forms black tetrahedra; sp gr, 7.7; a source of mercury. Also called metacinnabarite. Also spelled: metacinnibar metacinnabarite A mineral of the same composition as a cinnabar, but black in color, and crystallizing in isometric forms (tetrahedral). Used as a source of mercury. Sanford metaclase Leith's term for a rock possessing secondary cleavage, or cleavage in its modern meaning (1905). CF: protoclase metacryst Any large crystal developed in a metamorphic rock by recrystallization, such as garnet or staurolite in mica schists. metacrystal See: porphyroblast metadiabase

1956

A contraction of metamorphic diabase, suggested by Dana for certain rocks simulating diabase, but which were possibly produced by the metamorphism of sedimentary rocks. CF: metadiorite metadiorite a. A contraction of metamorphic diorite that was proposed for certain metamorphic rocks that resemble diorite, but which may have been the result of the metamorphism of sedimentary rocks. CF: metadiabase Fay b. Metamorphosed gabbro, diabase, or diorite. AGI metadolomite A metamorphic dolomite, or dolomite marble. metadurit Durain of a high-rank bituminous coal. See also: durain Tomkeieff metaglyph A hieroglyph formed during metamorphism. Pettijohn, 1 metahalloysite Dehydrated halloysite. See also: halloysite metaheinrichite A tetragonal mineral, Ba(UO2 )2 (AsO4 )2 .8H2 O ; meta-autunite group; yellow; a secondary mineral. Syn: arsenuranocircite; metasandbergite. CF: heinrichite metahewettite A monoclinic mineral, CaV6 O16 .3H2 O ; dark-red to yellow-brown; forms tabular crystals impregnating sandstone in southwest Colorado and southeast Utah. CF: hewettite metahohmannite A mineral, Fe2 (SO4 )2 (OH)2 .3H2 O . See also: hohmannite metahydroboracite

1957

A hydrous calcium and magnesium borate, CaMgB6 O8 (OH)6 .XH2 0 ; like hydroboracite but with more water. Syn: inderborite metakahlerite A tetragonal mineral, Fe(UO2 )2 (AsO4 )2 .8H2 O; meta-autunite group. metakirchheimerite A possibly tetragonal mineral, Co(UO2 )2 (AsO4 )2 .8H2 O ; meta-autunite group. metal In most cases, an opaque, lustrous, elemental substance that is a good conductor of heat and electricity. It is also malleable and ductile, possesses high melting and boiling points, and tends to form positive ions in chemical compounds. metal bath A bath, such as of mercury or tin, employed for chemical processes requiring high temperatures. metal drift A drift or heading driven in barren and hard rock. Nelson metaleucite A name for isometric leucite that is stable above 625 degrees C. CF: pseudoleucite metalimestone A metamorphosed carbonate rock not suitable for use as polished dimension stone (Brooks, 1954). CF: metamarble; ortholimestone. metalist A metallurgist. Standard, 2; Fay metalized slurry blasting The breaking of rocks, etc., using slurried explosive medium containing a powdered metal, such as powdered aluminum. metallic 1958

a. A term used to describe metal particles, such as gold in ores. Newton, 1 b. (adj.) The adj. indicates that the noun it modifies possesses metallic properties. These properties often include a metallike luster, conduction of electricity, tensile strength, opacity, and malleability, although some metallic materials may possess only a few such characteristics. c. When used with "mineral" in the context of resources, e.g., metallic mineral, it has a different and special meaning; it refers to the product, not the mineralogy. Thus chalcopyrite, CuFeS2 , is metallic (in the sense above), and the copper and iron it contains are metallic minerals in the resource sense. A single mineral, such as chalcopyrite, may also be the source of a nonmetal, sulfur. Adding to the confusion, rutile (TiO2 ) is the source of both titanium, which is used as metallic titanium, and titanium oxide, which is used as a nonmetallic mineral pigment. Because many industrial minerals (in a resource sense) tend to be nonmetallic (in either the mineralogical or the resource sense), the terms "industrial minerals" and "nonmetallic minerals" are sometimes carelessly used interchangeably. CF: mineral; nonmetallic mineral; industrial minerals. Syn: metalliferous metallic element Element that is generally distinguishable from nonmetallic elements by its luster, malleability, and electrical conductivity, and its usual ability to form positive ions. Henderson metallic iron Metal iron, as distinguished from iron ore. metallic luster The ordinary luster of metals. When feebly displayed, it is termed submetallic. Gold, iron pyrites, and galena have a metallic luster, e.g., while chromite and cuprite have a submetallic luster. Nelson metallic minerals Minerals with a high specific gravity and metallic luster, such as titanium, rutile, tungsten, uranium, tin, lead, iron, etc. In general, the metallic minerals are good conductors of heat and electricity. See also: nonmetallic minerals metallic ore From a strictly scientific point of view, the terms metallic ore and ore deposits have no clear significance. These are purely conventional expressions, used to describe those metalliferous minerals or bodies of mineral having economic value, from which useful metals can be advantageously extracted. In one sense, rock salt is an ore of sodium, and 1959

limestone an ore of calcium, but to term beds of those substances ore deposits would be quite outside of current usage. Ricketts metalliferous Metal-bearing; specif., pertaining to a mineral deposit from which a metal or metals can be extracted by metallurgical processes. See also: metallic metalliferous mud Marine deposit of mud formed under anoxic conditions and containing anomalously high quantities of zinc, silver, and copper, and lesser amounts of lead and gold. The term has most often been applied to deposits of muds in the Red Sea which have been formed by submarine precipitation of metallic sulfides from hydrothermal vents. These vents occur along the axis of a spreading center which forms the Red Sea Basin. Cruickshank metallify To convert into metal. Fay metallites A word used to embrace all ores or metalliferous material. metallization The process or processes by which metals are introduced into a rock, resulting in an economically valuable deposit; the mineralization of metals. AGI metallogenetic epoch The time interval favorable for the genesis or deposition of certain useful metals or minerals. Syn: minerogenetic epoch metallogenetic province See: minerogenetic province metallogenic element An element normally forming sulfides, selenides, tellurides, arsenides, antimonides, and/or sulfosalts, or occurring uncombined as a native element; i.e., an element of primary ore deposits. Schieferdecker metallogenic province 1960

a. An area characterized by a particular assemblage of mineral deposits, or by one or more characteristic types of mineralization. A metallogenic province may have had more than one episode of mineralization. Syn: metallographic province b. See: minerogenetic province metallogeny The study of the genesis of mineral deposits, with emphasis on its relationship in space and time to regional petrographic and tectonic features of the Earth's crust. The term has been used for both metallic and nonmetallic mineral deposits. Adj: metallogenic. Syn: ore geology CF: genesis metallograph An optical instrument designed for both visual observation and photomicrography of prepared surfaces of opaque materials, at magnifications ranging from about 25 to about 1,500 diameters. The instrument consists of a high-intensity illuminating source, a microscope, and a camera bellows. On some instruments, provisions are made for examination of specimen surfaces with polarized light, phase contrast, oblique illumination, dark-field illumination, and customary bright-field illumination. ASM, 1 metallographic province See: metallogenic province metallography a. The science dealing with the constitution and structure of metals and alloys as revealed by the unaided eye or by tools, such as low-power magnification, optical microscope, electron microscope, and diffraction or X-ray techniques. See also: reflected-light microscope b. The study of the constitution and structure of metals and alloys. metalloid a. A nonmetal, such as carbon or nitrogen, that can combine with a metal to form an alloy. Webster 3rd b. An element--such as boron, silicon, arsenic, or tellurium-intermediate in properties between the typical metals and nonmetals. Webster 3rd metalloidal luster a. Reflecting light, somewhat like a metal, but less than metallic luster. b. Having the luster of a semimetal; e.g., native bismuth or arsenic. metallometric surveying 1961

Geochemical prospecting term used by Russian authors for soil surveys or for the chemical analysis of systematically collected samples of soil and weathered rock. Hawkes, 2 metallometry The geochemical determination of metals. AGI metallo-organic compound A compound in which a metal combines with organic compounds to form metalloorganic complexes, such as porphyrins and salts of various organic acids. Some metalloorganic compounds are soluble in water, others are not. Hawkes, 2 metallurgical balance sheet Material balance of a process. metallurgical coke A coke with very high compressive strength at elevated temperatures, used in metallurgical furnaces, not only as a fuel, but also to support the weight of the charge. ASM, 1 metallurgical engineer One who applies engineering principles to the science and technology of metallurgy. CF: metallurgist metallurgical fume A mixture of fine particles of elements and metallic and nonmetallic compounds either sublimed or condensed from the vapor state. Fay metallurgical smoke A term applied to the gases and vapors, and fine dust entrained by them, that issue from the throats of furnaces; consists of three distinct substances: gases (including air), flue dust, and the fume. Fay metallurgist One who is skilled in, or who practices, metallurgy. CF: metallurgical engineer metallurgy 1962

a. The science and art of separating metals and metallic minerals from their ores by mechanical and chemical processes; the preparation of metalliferous materials from raw ore. b. Study of the physical properties of metals as affected by composition, mechanical working, and heat treatment. metal mining The industry that supplies the community with the various metals and associated products. Similar to coal mining, it is an extractive industry, and once the raw material, the orebody, is depleted it is not replenishable. See also: vein miner metal notch See: taphole metal pickling The immersion of metal objects in an acid bath to remove scale, oxide, tarnish, etc., leaving a chemically clean surface for galvanizing or painting. Nelson metal powder a. Metallic elements or alloys in finely divided or powder form. Henderson b. A general term applied by drillers, bit setters, and bit manufacturers to various finely ground metals, which, when mixed, are commonly used to produce sintered-metal diamond bit crowns. Also called powdered metal; powder metal. Long metal stone a. Newc. An argillaceous stone, shale, and sandstone. b. Staff. See: ironstone metamarble A marble suitable for use as polished dimension stone; e.g., the Vermont metamarble. CF: orthomarble; metalimestone. metamic A metal ceramic consisting of high Cr.Al2 O3 . Osborne metamict a. A mineral that has become virtually amorphous owing to the breakdown of the original crystal structure by internal bombardment with alpha particles (helium nuclei) emitted by radioactive atoms within the mineral. Many green zircons, esp. those from Sri 1963

Lanka, which are Precambrian in age, and have thus had over 800 million years of this internal bombardment, owe their low refractive index and density to this cause, and may be termed metamict zircons. Anderson b. Said of a mineral containing radioactive elements in which various degrees of lattice disruption and changes have taken place as a result of radiation damage, while its original external morphology has been retained. Examples occur in zircon, thorite and several other minerals. Not all minerals containing radioactive elements are metamict; e.g., xenotime and apatite are not. AGI metamictization The process of disruption of the structure of a crystal by radiations from contained radioactive atoms, rendering the material partly or wholly amorphous. AGI metamict mineral A mineral whose crystal structure has been disrupted by radiation from contained radioactive particles. AGI metamontmorillonite a. The product of dehydration of montmorillonite at 400 degrees C. Hey, 2 b. A dehydrated smectite. metamorphic Pertaining to the process of metamorphism or to its results. AGI metamorphic aureole See: aureole metamorphic deposit An ore deposit that has been subjected to great pressure, high temperature, and alteration by solutions. It may have become warped, twisted, or folded, and the original minerals may have been rearranged and recrystallized. metamorphic differentiation A collective term for the various processes by which minerals or mineral assemblages are locally segregated from an initially uniform parent rock during metamorphism; e.g., garnet porphyroblasts in fine-grained mica schist. AGI metamorphic diffusion 1964

Migration, by diffusion, of materials from one part of a rock mass to another during metamorphism. Diffusion may involve chemically active fluids from magmatic sources, hot pore fluids, or fluids released from hydrous minerals or carbonates. Ionic diffusion in the solid state may also occur. AGI metamorphic facies A set of metamorphic mineral assemblages, repeatedly associated in space and time, such that there is a constant and therefore predictable relation between mineral composition and chemical composition. It is generally assumed that the metamorphic facies represent the results of equilibrium crystallization of rocks under a restricted range of externally imposed physical conditions; e.g., temperature, lithostatic pressure, and water pressure. Syn: mineral facies metamorphic grade The intensity or rank of metamorphism, measured by the amount or degree of difference between the original parent rock and the metamorphic rock. It indicates in a general way the pressure-temperature environment or facies in which the metamorphism took place. For example, conversion of shale to slate or phyllite would be low-grade dynamothermal metamorphism (greenschist facies), whereas its continued alteration to a garnetsillimanite schist would be high-grade metamorphism (almandine-amphibolite facies). Syn: metamorphic rank See also: high-rank metamorphism metamorphic overprint See: overprint metamorphic rank See: metamorphic grade metamorphic rock Any rock derived from preexisting rocks by mineralogical, chemical, and/or structural changes, essentially in the solid state, in response to marked changes in temperature, pressure, shearing stress, and chemical environment, generally at depth in the Earth's crust. AGI metamorphic water Water driven out of rocks by metamorphism. Stokes metamorphism 1965

The mineralogical, chemical, and structural adjustment of solid rocks to physical and chemical conditions that have generally been imposed at depth below the surface zones of weathering and cementation, and that differ from the conditions under which the rocks in question originated. AGI metarossite A triclinic mineral, CaV2 O6 .2H2 O ; pearly to dull yellow; a dehydration product of rossite. metasandbergite See: metaheinrichite metasapropel Compact sapropel rock. Tomkeieff metaschoderite A monoclinic mineral, Al2 (PO4 )(VO4 ).6H2 O . metaschoepite Formerly called schoepite II. See also: schoepite; paraschoepite. metasediment A sediment or sedimentary rock that shows evidence of having been subjected to metamorphism. AGI metashale Shale altered by incipient metamorphic reconstitution but not recrystallized and without the development of partings or preferred mineral orientation. AGI metasomasis See: metasomatism metasomatic Pertaining to the process of metasomatism and to its results. The term is esp. used in connection with the origin of ore deposits. AGI 1966

metasomatism The process of practically simultaneous capillary solution and deposition by which a new mineral of partly or wholly different chemical composition may grow in the body of an old mineral or mineral aggregate. The presence of interstitial, chemically active pore liquids or gases contained within a rock body or introduced from external sources is essential for the replacement process, that often, though not necessarily, occurs at constant volume with little disturbance of textural or structural features. Syn: metasomosis metasomatite A rock produced by metasomatism. metasome a. A replacing mineral that grows in size at the expense of another mineral (the host or palasome); a mineral grain formed by metasomatism. AGI b. The newly formed part of a migmatite or composite rock, introduced during metasomatism. AGI metasomosis See: metasomatism metastrengite Monoclinic FePO4 .2H2 O , dimorphous with orthorhombic strengite; named to correspond with metavariscite and variscite AlPO4 .2H2 O . Syn: phosphosiderite; clinostrengite. Spencer, 4 metatorbernite A tetragonal mineral, Cu(UO2 )2 (PO4 )2 .8H2 O ; meta-autunite group; strongly radioactive; emerald to apple green; occurs in granite pegmatites. CF: torbernite metatyuyamunite An orthorhombic mineral, Ca(UO2 )2 V2 O8 .3H2 O ; yellow; radioactive; a secondary mineral. meta-uranocircite A monoclinic mineral, Ba(UO2 )2 (PO4 )2 .8H2 O ; meta-autunite group; yellow green; radioactive; a secondary mineral in quartz veins. 1967

meta-uranopilite A mineral, (UO2 )6 (SO4 )(OH)10 .5H2 O; radioactive. meta-uranospinite A tetragonal mineral, Ca(UO2 )(AsO4 )2 .8H2 O; meta-autunite group. metavariscite A monoclinic mineral, AlPO4 .2H2 O ; green; dimorphous with variscite. metavauxite A monoclinic mineral, FeAl2 (PO4 )2 (OH)2 .8H2 O ; dimorphous with paravauxite; forms acicular crystals or radiating fibrous aggregates. metavermiculite The product of dehydration of vermiculite at 400 degrees C. Hey, 2 metavolcanic Said of partly metamorphosed volcanic rock. Stokes metavoltine A hexagonal mineral, K2 Na6 Fe7 (SO4 )12 O2 .18H2 O . metaxite a. A fibrous serpentine mineral; a variety of chrysotile. AGI b. See: micaceous sandstone metazeunerite A tetragonal mineral, Cu(UO2 )2 (AsO4 )2 .8H2 O ; meta-autunite group; grass to emerald green. meteoric iron a. Iron of meteoric origin. AGI b. An iron meteorite. AGI meteoric stone

1968

a. A stone of meteoric origin; a stony meteorite. AGI b. A meteorite having the appearance of a stone. AGI meteoric water Ground water of atmospheric origin. meteorite A stony or metallic body that has fallen to the Earth's surface from outer space. Adj: meteoritic. meter a. An instrument, apparatus, or machine for measuring fluids, gases, electric currents, etc., and recording the results obtained; e.g., a gasmeter, a watermeter, or an air meter. Standard, 2 b. The fundamental unit of length in the metric system equal to 39.37079 in or 3.2808 ft. Standard, 2; Fay metering pin A valve plunger that controls the rate of flow of a liquid or a gas. Nichols, 1 methane CH4 ; carbureted hydrogen or marsh gas or combustible gases; formed by the decomposition of organic matter. The most common gas found in coal mines. It is a tasteless, colorless, nonpoisonous, and odorless gas; in mines the presence of impurities may give it a peculiar smell. It weighs less than air and may therefore form layers along the roof and occupy roof cavities. Methane will not support life or combustion; with air, however, it forms an explosive mixture, CH4 +2O2 -->CO2 .2H2 O. The gases resulting from a methane explosion are irrespirable. Methane is often referred to as combustible gases because it is the principal gas composing a mixture that, when combined with proper proportions of air, will explode when ignited. Breathing methane causes ill effects only where the air is so heavily laden with it that oxygen is supplanted. See also: colliery explosion; marsh gas; firedamp; limits of flammability. Nelson; Webster 2nd; BCI methane drainage a. Capture of the concentrated methane through boreholes drilled into a coalbed or associated strata. SME, 1 b. Outside the United States three main systems of methane drainage have been developed: (1) the cross-measure borehole method, (2) the superjacent roadway system and (3) the pack cavity system. The cross-measure borehole method which consists of boring holes from 2-1/4 to 3-1/4 in (5.7 to 8.3 cm) in diameter and 150 to 300 ft (45 to 90 m) in length, into the strata above or below the seam, 1969

generally close to the working face. This method has the advantage of being suited to a wide variety of conditions and does not require another seam within reasonable distance above or below the seam to be drained, or the use of solid stowing. Syn: cross-measure borehole system Boreholes are drilled from a roadway situated above the seam being worked, the drainage of the methane then taking place from this roadway. In the pack cavity system, corridors are left and supported in the goaf as the face advances, and from these combustible gases is drawn off. Syn: combustible gases drainage; corridor system. Sinclair, 1; Roberts, 1 c. In contrast to the above, methane drainage technology in the United States is conducted from the surface as well as underground. Underground methane drainage is primarily by means of horizontal boreholes drilled into the coalbed to be extracted. Surface methane drainage methods include vertical gob gas vent holes on longwall panels and hydraulically stimulated vertical wells generally drilled several years in advance of mining into virgin coalbeds. methane monitoring system A system whereby the methane content of the mine air is indicated automatically at all times. When the content reaches a predetermined concentration, the electric power is cut off automatically from each machine in the affected area. The mechanism is so devised that its setting cannot be altered. The system is used, mainly, in conjunction with the operation of continuous miners and power loaders. Nelson methanephone An instrument for detecting methane in mine air. It contains an electric battery that sustains a small electric glow light. As soon as a certain percentage of methane enters the workings, a tiny explosion occurs in the fuse head, where a fine wire filament is melted and starts a bell ringing continuously. Fay methane recorder An instrument that gives a continuous record of the methane concentration over a period of time. Roberts, 1 methane removal See: water infusion method methane tester A methane detector. See also: methanometer methane tester type S.3

1970

A nonautomatic methane detector approved under the regulations for use in coal mines. The instrument is normally calibrated at 1% methane, and this provides an accuracy of + or -0.05% over the most important part of the scale; i.e., 0.75% to 1.5%. It weighs 3-1/2 lb (1.6 kg), and the source of power is an Edison cap lamp battery. Nelson methanometer An instrument for determining the methane content in mine air. See also: sampling instrument; catalytic methanometer. Nelson methenyl tribromide See: bromoform method of working The system adopted to work or extract material in a mine. It includes all the operations involved in the cutting, handling, and transport of valuable material and waste rock, support of ground, ventilation of workings, and provision of supplies. The term does not include winding or hoisting, surface handling, and preparation or dressing. See also: coal mining methods method study A study to provide the essential data on which mine management can operate in making the most effective use of workpower, machines, and materials. Method study has been applied in the mining industry for many years, although sometimes under different names. See also: time study; work study. Nelson methyl acetone A mixture of methyl acetate and acetone. Used as a solvent. Crispin methylene iodide A heavy liquid used for mineral separation (sp gr, 3.33); also for refractive index determination (R.I.=1.74). CF: Clerici solution; Sonstadt solution; Klein solution; bromoform. metore Both capping and gossan. AGI metra 1971

A pocket implement combining the uses of many instruments, such as thermometer, level, plummet, and lens. Standard, 2 metric carat An international unit equal to 200 mg that had been adopted in most European countries and in Japan when it was made the standard in the United States in 1913. Abbrev.: M.C. and cm. See also: carat Webster 3rd Mexican diamond Rock crystal (quartz). Mexican onyx Yellowish brown or greenish brown banded calcite. See also: onyx marble; Gibraltar stone. Mexican turquoise Turquoise from the central part of Baja California, Mexico. Mexican water opal A fire opal from Mexico. meyerhofferite A triclinic mineral, Ca2 B6 O6 (OH)10 .2H2 O ; forms prismatic, commonly tabular, crystals or is fibrous; an alteration product of inyoite from Inyo County, CA. meymacite An amorphous mineral, WO3 .2H2 O ; resinous; yellow brown. miargyrite A monoclinic mineral, AgSbS2 ; soft; metallic; in low-temperature hydrothermal veins; an ore of silver. miarolite A granite having miarolitic cavities; a textural modification of normal granite. Johannsen 1972

miarolithite A chorismite having miarolitic cavities or remnants thereof; a variety of ophthalmite. AGI miarolitic A term applied to small irregular cavities in igneous rocks, esp. granites, into which small crystals of the rock-forming minerals protrude; characteristic of, pertaining to, or occurring in such cavities. Also, said of a rock containing such cavities. CF: drusy miarolitic cavity A cavity of irregular shape in certain plutonic rocks. Crystals of the rock constituents sometimes project into the cavity. CF: druse; vug. Schieferdecker miascite A mixture of strontianite and calcite. Hey, 1 mica a. A group of phyllosilicate minerals having the general composition, X2 Y4-6 Z8 O20 (OH,F) where X=(Ba,Ca,Cs,H3 O,K,Na,NH4 ), Y=(Al,Cr,Fe,Li,Mg,Mn,V,Zn), and Z=(Al,Be,Fe,Si); may be monoclinic, pseudohexagonal or pseudo-orthorhombic; soft; perfect basal (micaceous) cleavage yielding tough, elastic flakes and sheets; colorless, white, yellow, green, brown, or black; excellent electrical and thermal insulators (isinglass); common rock-forming minerals in igneous, metamorphic, and sedimentary rocks. See also: brittle mica. Syn: glimmer; isinglass. b. The mineral group anandite, annite, biotite, bityite, celadonite, chernykhite, clintonite, ephesite, ferri-annite, glauconite, hendricksite, kinoshitalite, lepidolite, margarite, masutomilite, montdorite, muscovite, nanpingite, norrishite, paragonite, phlogopite, polylithionite, preiswerkite, roscoelite, siderophyllite, sodium phlogopite, taeniolite, tobelite, wonesite, and zinnwaldite. micaceous a. Consisting of or containing mica; e.g., a micaceous sediment. b. Resembling mica; i.e., thinly foliated. micaceous iron ore Hematite in which the texture is foliated or micaceous; some micaceous varieties are soft and unctuous. Rice, 1 1973

micaceous sandstone A sandstone containing conspicuous layers or flakes of mica, usually muscovite. Syn: metaxite mica house A shop where hand-cobbed mica is rifted, trimmed, graded, and qualified. Syn: trimming shed Micanite Trade name for a form of built-up mica used for insulating. mica peridotite A peridotite consisting principally of altered olivine and biotite. mica plate An accessory introduced into the optic path of a polarized-light microscope to produce a first-order gray interference color. Syn: glimmer plate; lambda plate. See also: accessory plate mica powder A dynamite in which the dope consists of fine scales of mica. Fay mica schist A schist whose essential constituents are mica and quartz, and whose schistosity is mainly due to the parallel arrangement of mica flakes. michenerite An isometric mineral, (Pd,Pt)BiTe ; pyrite group; metallic; at Sudbury, ON, Canada and Monchegorsk, Kola Peninsula, Russia. Michigan cut a. In the United States, a cut that consists of drilling a hole with a large diameter or a number of holes of smaller diameter at the center of the heading and parallel to the direction of the tunnel. These holes are not charged. The remaining bench holes are then broken out towards these holes. Fraenkel b. See: burned cut 1974

Michigan slip A very plastic, tough, fine-grained impure clay, similar to Albany slip clay; used as a bonding and plasticizing agent in grinding wheels, refractories, etc., and as a suspension agent for glassy frit in vitreous enamels. CCD, 1 micrinite a. A maceral of the inertinite group consisting of granular material without cellular structure; one of the principal components of durain and clarain. AGI b. Proposed by the Heerlen Congress, 1935, as a substitute for micronite. Tomkeieff micrinoid A coal constituent similar to material derived from finely macerated vegetation. AGI micrite a. A descriptive term originally used for the semiopaque crystalline matrix of limestones, consisting of chemically precipitated carbonate mud with crystals less than 4 mu m in diameter, and interpreted as a lithified ooze. The term is now commonly used in a descriptive sense without genetic implication. AGI b. A limestone consisting dominantly of micrite matrix; e.g., lithographic limestone. AGI microa. A prefix that divides a basic unit by 1 million or multiplies it by 10-6 . Abbrev., mu . Lyman b. A prefix meaning small. When modifying a rock name, it signifies fine-grained hypabyssal, as in microgranite. CF: macromicroampere One-millionth of an ampere; 10-6 A; abbrev., mu a. Crispin microaphanitic See: cryptocrystalline microballoon One of the tiny hollow spheres of glass or plastic that are added to explosive materials to enhance sensitivity and control density by assuring an adequate content of entrapped air. Atlas microbar 1975

A unit of pressure commonly used in acoustics. One microbar is equal to 1 dyn/cm2 . Hunt microbreccia a. A poorly sorted sandstone containing large angular particles of sand set in a fine silty or clayey matrix; e.g., a graywacke. It is somewhat less micaceous than a siltstone. AGI b. A breccia within fragments of a coarser breccia. AGI c. A well-indurated, massive rock that has been crushed to very fine grain size through cataclastic flow, commonly in detachment faults. AGI microchemical Applied to chemical reactions conducted on the stage of a microscope and viewed through the microscope. microclastic a. Applied to a clastic or fragmental rock composed of very small particles. b. Said of coal that is composed mainly of fine particles; e.g., cannel coal. AGI microcline A triclinic mineral, KAlSi3 O8 ; feldspar group; pseudomonoclinic; dimorphous with orthoclase; a major rock-forming mineral in granites, pegmatites, and metamorphic rocks; may be a detrital mineral in arkoses and graywackes. CF: orthoclase microconglomerate A sedimentary rock composed of relatively coarse sand grains in a very fine silt or clay matrix. AGI microcosmic salt See: stercorite microcryptocrystalline See: cryptocrystalline microcrystalline Said of the texture of a rock consisting of or having crystals that are small enough to be visible only under the microscope; also, said of a rock with such a texture. Syn: cryptocrystalline; micromeritic. AGI 1976

microelement See: trace element microfacies Those characteristic and distinctive aspects of a sedimentary rock that are visible and identifiable only under the microscope (low-power magnification). AGI microfarad A unit of capacitance; one-millionth of a farad; symbol, mu F. Crispin microfelsitic See: cryptocrystalline microfluidal Having a microscopic flow texture. Standard, 2 microgeology a. The study of the microscopic features of rocks. b. The study of the relationships of microorganisms to geologic and geochemical processes. microgranitoid Having a microscopic granitoid structure. Standard, 2 microgranular a. Said of the texture of a microcrystalline, xenomorphic igneous rock. Also, said of a rock with such a texture. AGI b. Minutely granular; specif. said of the texture of a carbonate sedimentary rock wherein the particles are mostly 10 to 60 mu m in diameter and are well-sorted, and the finer clay-sized matrix is absent. Also said of a sedimentary rock with such a texture. AGI micrograph A graphic reproduction of a magnified object as seen through a microscope. When it is a photograph, it is called a photomicrograph. Stokes micrographic 1977

Said of the graphic texture of an igneous rock that is distinguishable only with the aid of a microscope; also, said of a rock having such texture. AGI microhardness The hardness of microscopic areas or of the individual microconstituents in a metal, as measured by means such as the Tukon, Knoop, or scratch methods. ASM, 1 microhm One microhm equals 10-6 Omega , which equals 103 electromagnetic units. Symbol, mu Omega . Webster 2nd microite Microite is found in many coals and occurs in large quantities in Gondwana coals and in Permocarboniferous coals of the former U.S.S.R. It is most abundant in coals with little exinite, or coals of high rank in which exinite cannot be recognized, and may occur in very persistent thick bands. It is present in small amounts in Carboniferous coals of the Northern Hemisphere. IHCP microlaterolog A well log obtained with an arrangement of electrodes similar to a miniature laterolog but disposed in concentric fashion in an insulating pad. The current from a central electrode is focused and flows out in a pattern that resembles the shape of a trumpet. As in the microlog, the electrodes are mounted on a pad that is held against the wall of the hole by springs. The microlaterolog serves a purpose similar to that of a microlog, investigating only a small volume of rock immediately adjacent to the hole. Syn: trumpet log microlite a. A microscopic crystal that polarizes light and has some determinable optical properties. CF: crystallite; crystalloid. Syn: microlith AGI b. A pale-yellow, reddish, brown, or black isometric mineral of the pyrochlore group: (Ca,Na)2 Ta2 O6 (O,OH,F). It is isomorphous with pyrochlore, and it often contains small amounts of other elements (including uranium and titanium). Microlite occurs in granitic pegmatites and in pegmatites related to alkalic igneous rocks, and it constitutes an ore of tantalum. Syn: djalmaite microlith See: microlite 1978

microlithotype A typical association of macerals in coals, occurring in bands at least 50 mu m wide. Microlithotype names bear the suffix "-ite". See also: lithotype microlitic Said of the texture of a porphyritic igneous rock in which the groundmass is composed of an aggregate of differently oriented or parallel microlites in a glassy or cryptocrystalline mesostasis. AGI micromanometer Essentially a U-type gage employing a micrometer to measure the change in inclination of the gage from its zero or datum position. Normally, micromanometers are used in the laboratory for such purposes as the calibration of secondary manometers and, in conjunction with pressure measurement, in low-speed atmospheric wind tunnels. See also: manometer Roberts, 1 micromeritic An obsolete syn. of microcrystalline. See also: microcrystalline AGI micrometer a. An instrument for measuring very small dimensions or angles. Used in connection with a microscope or a telescope. There are a great variety of forms, but in nearly all, the measurement is made by turning a very fine screw, which gives motion to a scale, a spider line, a lens, a prism, or a ruled glass plate. Standard, 2 b. A unit of length, equal to one-millionth of a meter. Symbol, mu m. (1 mu m = 10-6 m). Formerly called micron. c. A micrometer caliper. Standard, 2 micrometer caliper A caliper with a graduated screw attachment for measuring minute distances. Crispin micrometer-reading manometer See: vernier-reading manometer micrometrics The study of very fine particles. AGI micromillimeter 1979

One-millionth of a millimeter; abbrev., mmu . AGI micron Former term for micrometer. micronized mica An ultrafine material produced in a disintegrator that has no moving parts but depends on jets of high-pressure superheated steam to reduce the mica to micrometer sizes. Micronized mica is produced in particle size ranges of 10 to 20 mu m and 5 to 10 mu m. USBM, 7 Micronizer A special type of dry-grinding machine in which micronized mica is produced. It consists of a disintegrator that has no moving parts but depends on jets of high-pressure superheated steam for reducing the mica to micrometer sizes. USBM, 7 micronizer mill Disintegrator, in which feed particles are entrained in a pressure jet (steam or air) and whirled through a cylindrical chamber with sufficient force to break them. Pryor, 3 micropegmatite A less-preferred syn. of granophyre. See also: granophyre microperthite Exsolution lamellae in alkali feldspar visible only with the aid of a microscope. See also: cryptoperthite; perthite. micropetrological unit See: maceral microphotograph See: photomicrograph microporosity Porosity visible only with the aid of a microscope. ASM, 1 1980

microscope An instrument used to produce enlarged images; it consists of a lens (or lenses) of the objective and an ocular set into a tube, with or without other accessories, and held by an adjustable arm over an object stage. microscopic a. Of, relating to, or conducted with a microscope or microscopy. Webster 3rd b. So small or fine as to be invisible or not clearly distinguishable without the use of a microscope. CF: macroscopic; megascopic. Webster 3rd microscopy The art and practice of using a microscope for identification and analysis of objects. See also: ore microscopy; reflected-light microscope. microsecond One-millionth of a second; abbrev.: mu sec, mu s. Webster 3rd microsection a. Any thin section used in microscopic analysis. AGI b. A polished section. AGI microseism A collective term for small motions in the Earth that are unrelated to an earthquake and that have a period of 1.0 to 9.0 s. They are caused by a variety of natural and artificial agents, esp. atmospheric events. Syn: seismic noise microseismic instrument An instrument for observing the behavior of roof strata and supports. The device is inserted in 4-ft (1.2-m) long 1-1/2-in (3.8-cm) diameter holes, drilled at selected points, for listening to subaudible vibrations which are known to precede rock failure. Nelson microseismic movement See: microseism. microseismic rate The number of microseisms per unit of time. Issacson 1981

microseismic region Area in which an earthquake is registered by instruments only. Schieferdecker microseismometer An apparatus for indicating the direction, duration, and intensity of microseisms. Also called microseismograph. Standard, 2 microspar Calcite matrix in limestones, occurring as uniformly sized and generally loaf-shaped crystals ranging from 5 mu m to more than 20 mu m in diameter. AGI microspherulitic Said of the spherulitic texture of an igneous rock that is distinguishable only with the aid of a microscope, owing to the small size of the spherules. Also, said of a rock having such texture. AGI microstriation Microscopic scratch developed on the polished surface of a rock or mineral as a result of abrasion. AGI microstructure a. Structural features of rocks that can be discerned only with the aid of the microscope. AGI b. The structure of polished and etched metals as revealed by a microscope at a magnification greater than 10 diameters. ASM, 1 microstylolite A type of grain boundary indicating differential solution between two minerals and characterized by fine interpenetrating teeth; often marked by a little opaque material. See also: stylolite microvitrain The thin vitrainlike bands present in clarain, having a maximum thickness of about 1/10 in (2.5 mm) with a tolerance of 1 mm, and a minimum thickness of 0.05 mm (50 mu m). AGI microvolt 1982

One-millionth of a volt; 10-6 V; symbol, mu V. Crispin microwatt One-millionth of a watt; symbol, mu W. Webster 3rd midalkalite See: foyaite; nepheline syenite. Mid-Atlantic Ridge A mountain range that extends parallel to the continental margins in mid-ocean in both the North and South Atlantic Oceans. It rises 6,000 ft above the ocean floor and surfaces as the Azores, Ascension Island, Saint Helena, and Tristan da Cunha islands. AGI middle Pertaining to a segment of geologic time intermediate between Late and Early, or to rocks intermediate between Upper and Lower. Thus, rocks of the Middle Jurassic Series were formed during the Middle Jurassic Epoch. CF: Upper; Lower. middle cut A machine cut in the midsection of a coal seam; sometimes adopted in thick seams (over 4 ft or 1.2 m) with a layer of dirt or inferior coal in the middle. A middle cut would be made with a turret coal cutter. See also: bottom cut; top cut. Syn: intermediate cut middle man A stratum of rock dividing or separating two seams or beds of coal. Fay middle prop See: center prop middles See: middlings middletonite A brown, resinous, brittle mineral found between layers of coal at the Middleton collieries, near Leeds, England, and also at Newcastle. Fay 1983

middlings a. That part of the product of a washery, concentration, or preparation plant that is neither clean mineral product nor reject (tailings). It consists of fragments of coal ore mineral and gangue. The material is often sent back for crushing and/or retreatment. Syn: middles Nelson b. In two-component ore, particles incompletely liberated by comminution into concentrate or gangue. In complex ores, in addition to incomplete liberation, there may be multiphased particles of middling or intermediate species that react too feebly to treatment to report as concentrate or tailing. Pryor, 2 middlings elevator An elevator that removes material for further treatment or for disposal as an inferior product. BS, 5 middoor Scot. The middle one of three landing places in a shaft. Fay midfeather In mining, a support to the center of a tunnel. Standard, 2 midge N. of Eng. Lamp (not safety) carried by trammers, etc. Fay midge stone Moss agate with inclusions resembling a swarm of mosquitoes. Also called gnat stone; mosquito agate. midget impinger A dust-sampling apparatus almost identical in principle and design with the regular Greenburg-Smith impinger, the main difference being its smaller size and the fact that only a 12-in (30.5-cm) head of water is required for its operation. See also: GreenburgSmith impinger mid-ocean ridge A continuous, seismic, median mountain range extending through the North and South Atlantic Oceans, the Indian Ocean, and the South Pacific Ocean. It is a broad, fractured swell with a central rift valley and usually extremely rugged topography; it is 1 to 3 km in elevation, about 1,500 km in width, and over 84,000 km in length. According to the 1984

hypothesis of sea-floor spreading, the mid-ocean ridge is the source of new crustal material. See also: rift valley AGI midocean rift See: rift valley mid-ocean rise See: mid-ocean ridge midworkings a. Scot. Mine workings above or below in the same mine or colliery. Fay b. See: middoor miemite A variety of dolomite from Miemo, Tuscany, Italy. miersite An isometric mineral, (Ag,Cu)I ; canary yellow. miesite A brown variety of pyromorphite containing calcium from Mies, Czech Republic. migma Mobile, or potentially mobile, mixture of solid rock material(s) and magma, the magma having been injected into or melted out of the rock material. Etymol: Greek, mixture. AGI migmatite A composite rock composed of igneous or igneous-appearing and/or metamorphic materials that are generally distinguishable megascopically. See also: composite gneiss AGI migmatization Formation of a migmatite. The more mobile, typically light-colored, part of a migmatite may be formed as the result of anatexis, lateral secretion, metasomatism, or injection. AGI 1985

migration a. The movement of oil, gas, or water through porous and permeable rock. Parallel (longitudinal) migration is movement parallel to the bedding plane. Transverse migration is movement across the bedding plane. AGI b. The process by which events on a reflection seismogram are mapped in an approximation of their true spatial positions. It requires knowledge of the velocity distribution along the raypath. Also, the seismic correction that is applied. AGI; Schieferdecker c. The movement of a topographic feature from one locality to another by the operation of natural forces; specif. the movement of a dune by the continual transfer of sand from its windward to its leeward side. AGI d. The slow downstream movement of a system of meanders, accompanied by enlargement of the curves and widening of the meander belt. AGI e. A broad term applied to the movements of plants and animals from one place to another over long periods of time. AGI migration of oil The movement or seepage of oil through rocks wherever they are sufficiently permeable to allow such passage; of considerable importance in oil geology. Nelson mikheevite See: goergeyite milarite A hexagonal mineral, K2 Ca4 Al2 Be4 Si24 O60 .H2 O ; osumilite group; forms colorless to greenish prisms. (Not millerite.) mild and tough Mellowed or ripened by weathering; said of brick clay; opposite of short and rough. Standard, 2 mild earth Eng. Soft, loamy clay suitable for brickmaking, as opposed to stiffer clay below, which is suitable for making tiles and drainpipes. Kimeridge clay, Brill, Buckinghamshire. Arkell mild steel Steel that contains from 0.12% to 0.25% carbon. Also called low-carbon steel; soft steel. See also: yield stress 1986

mil-foot A standard of resistance in wire. The resistance of 1 ft (30.5 cm) of wire that is 1 mil (25.4 mu m) in diameter. Crispin milk of sulfur See: colloidal sulfur milk-opal A translucent, milk-white to green, yellow, or blue variety of common opal. milky quartz A milk-white, nearly opaque variety of quartz, commonly with a greasy luster. The milkiness is due to the presence of minute, fluid-filled inclusions. Syn: greasy quartz mill a. A mineral treatment plant in which crushing, wet grinding, and further treatment of ore is conducted. Also, separate components, such as ball mill, hammer mill, and rod mill. See also: ball mill; hammermill; rod mill; grinding mill; pug mill. b. A passage connecting a stope or upper level with a level below, intended to be filled with broken ore that can then be drawn out at the bottom as desired for further transportation; an opening in the floor or bottom of a stope, through which the ore or mineral is passed or thrown downward along the footwall to the level. See also: glory hole Fay c. To fill a winze, or interior incline, with broken ore, to be drawn out at the bottom. Fay d. A finishing plant where blocks of stone are sawed and trimmed. e. In quarrying, usually applied to the finishing plant where blocks are sawed into slabs; all other manufacturing processes are classed as shop work. AIME, 1 f. An excavation made in the country rock, by a crosscut from the workings on a vein, to obtain waste for filling. It is left without timber so that the roof may fall in and furnish the required rock. Fay g. Can. Reducing plant where ore is concentrated and/or metals are recovered. Hoffman h. A single machine or a complete plant for rolling metals. i. See: cogging mill j. To grind or cut away steel or iron with a toothed or serrated face bit; also, the tool so used. Long k. Eng. That part of an ironworks where puddle bars are converted into merchant iron; i.e., rolled iron ready for sale in bars, rods, or sheets. See also: forge l. A preparation facility within which metal ore is cleaned, concentrated, or otherwise processed before it is shipped to the customer, refiner, smelter, or manufacturer. A mill includes all ancillary operations and structures necessary to clean, concentrate, or otherwise process metal ore, such as ore and gangue storage areas and loading facilities. SME, 1 m. By common usage, any establishment for reducing ores by other means than smelting. More strictly, a place or a machine in which ore or rock is crushed. Fay 1987

mill bar A rough bar rolled or drawn directly from a bloom or puddle bar for conversion into merchant iron in the mill. mill car A car without a roof for carrying hoisting apparatus. Standard, 2 milled A metal object lost in a borehole that has been cut or ground away with a milling bit. Long Miller-Bravais indices A four-index type of Miller indices, useful but not necessary in order to define planes in crystal lattices in the hexagonal system; the symbols are hkil, in which i = -(h + k). CF: Miller indices Miller indices Integers used to designate crystallographic planes. They are found as follows: (1) Determine where the plane intercepts each crystallographic axis in terms of multiples of the axial parameters; (2) take the reciprocals of these numbers and clear of fractions and common factors. These three numbers, designated (hkl), are the Miller indices for that plane. CF: Bragg indices; Miller-Bravais indices; crystal face; crystal indices; intercept. See also: symbols of crystal faces; indices of a crystal face. millerite A brass-yellow to bronze-yellow rhombohedral mineral: NiS. It usually has traces of cobalt, copper, and iron, and is often tarnished. Millerite generally occurs in fine hairlike or capillary crystals of extreme delicacy, chiefly as nodules in clay ironstone. Syn: capillary pyrite; nickel pyrite; hair pyrite. (Not milarite.) AGI mill feeder In ore dressing, smelting, and refining, a laborer who regulates flow of ore, coke, flue scrapings, or other materials from bins, chutes, or belts into crushers, furnaces, or other equipment, or onto conveyor belts leading to equipment. Syn: conveyor-feeder operator mill furnace

1988

A furnace for reheating iron that is to be rerolled, or welded, under a hammer. Standard, 2 millgrit rock Som. Triassic dolomitic conglomerate. mill head a. Ore accepted for treatment in a concentrator, after any preliminary rejection such as waste removal. Pryor, 4 b. Assay value, or units of value per ton, in ore accepted for treatment in a concentrating plant or mill. Pryor, 3 mill-head grade The grade of ore as it comes from a mine and goes to a mill. McKinstry mill-head ore See: run-of-mill mill hole An auxiliary shaft connecting a stope or other excavation with the level below. See also: mill; glory hole. Lewis milliA prefix meaning one thousandth of. It divides a basic unit by 1,000, or multiplies it by 10-3 ; abbrev., m. Commonly applied to units of measure in the metric and cgs systems; e.g., 1 mg = 0.001 g. Lyman milliampere One-thousandth of an ampere; abbrev., mA. Crispin milliangstrom One-thousandth of an angstrom; abbrev., mAa. Webster 3rd millibar A unit of atmospheric pressure equal to one-thousandth of a bar or 1,000 dyn/cm2 ; abbrev., mb. Webster 3rd 1989

millicurie-hour A measure of gamma-ray exposure expressed as the product of the source in millicuries and the time of exposure in hours. NCB millidarcy The customary unit of measurement of permeability, equal to one-thousandth of a darcy. See also: permeability AGI; Webster 3rd millidegree A unit of temperature equal to one-thousandth of a degree; abbrev., mdeg. Webster 3rd millifarad One-thousandth of a farad; abbrev., mF. Webster 3rd milligal a. A unit employed in the gravitational method of geophysical prospecting. It is about one millionth of the average value of the acceleration due to gravity at the Earth's surface; i.e., 1 milligal = 1 cm/s2 . Nelson b. A unit of acceleration used with gravity measurements; 10-3 Gal = 10-5 m/s2 . Abbrev: mGal. AGI milligauss One-thousandth of a gauss; abbrev., mG. Standard, 2 milligram-hour A measure of gamma-ray exposure expressed as the product of the equivalent radium content of the source, in milligrams, and the time of exposure in hours. NCB millihenry One-thousandth of a henry; a unit of inductance; abbrev., mH. Webster 3rd millimeter screw micrometer A precision caliper gage that measures the overall dimensions of unmounted fashioned gems more accurately but less conveniently than dial gages. milling 1990

a. The grinding or crushing of ore. The term may include the operation of removing valueless or harmful constituents and preparation for market. Nelson b. A combination of open-cut and underground mining, wherein the ore is mined in open cut and handled underground. It is underhand stoping applied to large deposits, wherein the ore is mined near the mouth of winzes or raises, and dropped by gravity to working levels below for transportation to the surface. Usually called glory-hole system. See also: mill c. The act or process of cutting or grinding away a metal object lost in a borehole with a mill or milling bit. Long milling bit A bit equipped with hardened serrations or teeth used to grind or cut away metallic materials or junk obstructing a borehole. Also called rose bit. CF: junk mill milling grade a. Ore containing sufficient recoverable value to warrant treatment. Pryor, 3 b. S. Afr. An assumed average value of the ore sent to a mill, expressed as a percentage, or in pennyweights per short ton. Beerman milling ore a. Any ore that contains sufficient valuable minerals to be treated by any milling process. Syn: mill ore b. A dry ore that can be amalgamated or treated by leaching and other processes; usually these ores are low grade and free, or nearly so, from base metals. milling width Width of a lode that is designated for treatment in a mill, as calculated with regard to daily tonnage. Any excess broken during mining (stoping width) should be rejected before milling. Pryor, 3 milling yield S. Afr. The valuable material obtained from milling, expressed as a percentage or in pennyweights per short ton. Beerman millisecond One-thousandth of a second; abbrev.: msec; ms. Webster 3rd millisecond delay A type of delay cap with a definite but extremely short interval between the passing of current and the explosion. Nichols, 1 1991

millisecond-delay cap A detonating cap that fires from 0.02 to 0.5 s after the firing current passes through it. Nichols, 1 millisecond-delay detonator See: short-delay detonator millivolt One-thousandth of a volt; abbrev., mV. Crispin millman One who is employed in a mill, such as in an ore-dressing plant. Fay mill ore See: milling ore mill roll One of the rolls through which puddled iron is run prior to being marketed. Standard, 2 mill run a. A given quantity of ore tested for its quality by actual milling; the yield of such a test. Craigie b. Average, not esp. selected. Craigie c. In intermittent treatment of ore, with periodic cleanup, the period of such a run. Bulk test on a sample of ore during development of a treatment process. Pryor, 3 mill sampler A laborer who removes samples of crushed ore, concentrates, or tailings at various stages of processing, and puts them in labeled containers for laboratory analysis. Also called sampler. DOT mill scale The scale of ferric oxide that peels from iron during rolling. Standard, 2 Mills-Crowe process

1992

Method of regeneration of foul cyanide liquor from the gold leaching process. The barren solution is acidified, and gaseous hydrocyanic acid (HCN) is liberated, separated, and reabsorbed in an alkaline solution, such as lime water. Pryor, 3 mill shoe a. A shoe equipped with a hardened serrated cutting edge used to mill downward over and around a piece of drill-stem equipment lost in a borehole. See also: mill b. A shoe designed either to dress the down-hole tools for access to retrieve them, or to grind up the tool in a drill hole so that drilling can continue. millstock Term used in the slate industry to include all forms of structural slate used in exterior or interior construction. millstone A buhrstone; e.g., a coarse-grained sandstone or a fine-grained quartz conglomerate. Also, one of two thick disks of such material used for grinding grain and other materials fed through a center hole in the upper stone. Quarried underground in Virginia; also, produced in New York and (of granite) in North Carolina. See also: buhrstone millstone grit Any hard, siliceous rock suitable for use as a material for millstones; specif. the Millstone Grit of the British Carboniferous, a coarse conglomeratic sandstone. AGI mill test The determination of the metallic contents and recoverable metal in any given ore by the milling of a sufficient quantity to afford average milling conditions. See also: mill run milltons Net tonnage of ore available for milling after eliminating waste and unpayable material. Beerman mill value S. Afr. The calculated value of ore before crushing. After treatment, there remains a residue of the valuable metal in the sands, slimes, or tailings, which, added to the yield obtained by treatment, should be equal to the mill value. Beerman mimetene 1993

See: mimetite mimetesite See: mimetite mimetic a. Said of crystals appearing to have a higher symmetry than their internal structure due to twinning, distortion, or interfacial angles at or close to a more symmetric form. b. Said of crystals showing highly complex pseudosymmetry. CF: pseudosymmetry c. A tectonite with a deformation fabric influenced by preexisting structural anisotropy; also the fabric itself. mimetite A monoclinic mineral, Pb5 Cl(AsO4 )3 ; apatite group, with arsenate replaced by phosphate; pseudohexagonal; resinous; sp gr, 7.3; in oxidized zones of lead-ore deposits. Syn: mimetesite; campylite; mimetene. CF: hedyphane minal See: end member minasragrite A monoclinic mineral, VO(SO4 ).5H2 O ; a blue efflorescence at Minasragra, near Cerro de Pasco, Peru. mine a. An opening or excavation in the ground for the purpose of extracting minerals; a pit or excavation from which ores or other mineral substances are taken by digging; an opening in the ground made for the purpose of taking out minerals, and in case of coal mines, commonly a worked vein; an excavation properly underground for digging out some usual product, such as ore, metal, or coal, including any deposit of any material suitable for excavation and working as a placer mine; collectively, the underground passage and workings and the minerals themselves. Ricketts b. A work for the excavation of minerals by means of pits, shafts, levels, tunnels, etc., as opposed to a quarry, where the whole excavation is open. In general, the existence of a mine is determined by the mode in which the mineral is obtained, and not by its chemical or geological character. The term also includes only excavations for their minerals or valuable mineral deposits. Ricketts c. An excavation beneath the surface of the ground from which mineral matter of value is extracted. The word carries the sense of laborers working beneath a cover of ground and thus excludes oil, brine, and sulfur wells. Excavations for the extraction of ore or 1994

other economic minerals not requiring work beneath the surface are designated by a modifying word or phrase as: (1) opencut mine--an excavation for removing minerals that is open to the weather; (2) steam shovel mine--an opencut mine in which steam shovels or other power shovels are used for loading cars; (3) strip mine--a stripping; an opencut mine in which the overburden is removed from a coalbed before the coal is taken out; (4) placer mine--a deposit of sand, gravel, or talus from which some valuable mineral is extracted; and (5) hydraulic mine--a placer mine worked by means of a stream of water directed against a bank of sand, gravel, or talus; soft rock similarly worked. A quarry from which rock is extracted becomes a mine when it is carried under cover. Mines are commonly known by the mineral or metal extracted such as bauxite mines, copper mines, silver mines, coal mines, etc. Hess d. The terms mine and coal mine are intended to signify any and all parts of the property of a mining plant, either on the surface or underground, that contribute directly or indirectly to the mining or handling of coal or ore. Fay e. The term mine, as applied by quarrymen, is applied to underground workings having a roof of undisturbed rock. It is used in contrast with the open pit quarry. Fay f. To dig a mine; to get ore, metals, coal, or precious stones out of the earth; to dig into, as the ground, for ore or metal; to work in a mine. Webster 3rd g. An active mining area, including all land and property placed under, or above the surface of such land, used in or resulting from the work of extracting metal ore or minerals from their natural deposits by any means or method, including secondary recovery of metal ore from refuse or other storage piles, wastes, or rock dumps and mill tailings derived from the mining, cleaning, or concentration of metal ores. CFR, 7 mine atmosphere The concentration of gases, including oxygen, that are present in a mine. Safe levels are maintained through ventilation. Measured at any point at least 12 in (30.5 cm) away from the back, face, rib, and floor in any mine. CFR, 1 mine bank a. An area of ore deposits that can be worked by excavations above the water level. Craigie b. The ground at the top of a mining shaft. Craigie mine cage Elevator used to transport workers in a lined shaft; available in open, semienclosed or fully enclosed models with a choice of sliding, folding, or rollup doors. Cages are used in either vertical or incline mine shafts. All cages are required to contain necessary safety features. Best, 1 mine captain a. A superintendent of a mine. Standard, 2 b. The director of work in a mine, with or without superior officials or subordinates. Fay c. In metal mining, a foreman who 1995

supervises the extraction, hauling, and hoisting of ore in a mine. Also called ground boss. DOT mine car One of the cars that are loaded at production points and hauled to the pit bottom or surface in a train by locomotives or other power. They vary in capacity, and are either of wood or steel construction or combinations of both. Mine cars have been classified into six kinds: (1) the solid or box type, which requires a rotary dump at the unloading terminal; (2) the rocker dump type, which has a V-shaped body rounded at the bottom; (3) the gable-bottom car, which is shaped like a capital W in cross section; (4) the Granby car, a special form of a side-dumping car; (5) bottom-dump cars; and (6) enddump cars, which are commonly used for hand tramming in small mines. See also: dropbottom car; endgate car; gable-bottom car; Granby car; solid car. BCI; Kentucky; Lewis mine-car repairman In anthracite coal mining; bituminous coal mining; metal mining; nonmetal mining, a person who repairs or replaces damaged parts of mine (pit) cars, such as axles, wheels, bodies, and couplings, by straightening, bolting, riveting, refitting, or making new parts as required. Also called car whacker; pit-car repairer. DOT mine characteristic The relation between pressure, p, and volume, Q, in the ventilation of a mine. If the resistance, R, of the mine is known, then the mine characteristic can be expressed as p=RQ2 . The curve of this equation for a particular mine may thus be plotted on the same axes as the characteristics of a fan. The point of intersection of this curve, termed the mine characteristic, with the pressure characteristic of the fan, indicates the pressure and volume at which the fan would work in ventilating that mine. Knowing the volume and pressure, the power and efficiency are obtained. The suitability of any fan to any mine can be studied, and the effect of possible changes in mine resistance may be predicted. Roberts, 1 mine characteristic curve As a graphical aid to the solution of problems in mine ventilation, the mine head (static and/or total) is often plotted against the quantity. This is called the mine characteristic curve, or simply the mine characteristic. Hartman, 2 mine circulating fan Mines create special problems in proper ventilation by their isolation from fresh air sources, and the presence of dangerous gases and dusts. Large fans are used for the stationary systems, while small portable types provide fresh air in dead-ends and other 1996

inaccessible locations. These fans may be driven by electricity or compressed air, and in addition to mine operations, are useful for work in manholes, pipe galleries, silos, tanks, vats, plane fuselages, ship holds, etc. The Mine Safety and Health Administration, Department of Labor can furnish specific recommendations concerning special problems. Best, 1 mine committee Representatives chosen by the union employees to confer with the representatives of the company; corresponds in mining to shop committees in manufacturing. Also called pit committee. BCI mine conveyor See: underground mine conveyor mine cooling load The total amount of heat, sensible and latent, which must be removed by the air in the working places. Hartman, 2 mine development The term employed to designate the operations involved in preparing a mine for ore extraction. These operations include tunneling, sinking, crosscutting, drifting and raising. Jackson, 3 mine dial See: miner's dial mine door See: trapdoor; door. mine drainage See: drainage; drain tunnel; water hoist. mined strata In mine subsidence, the strata lying over the excavated area. Briggs mine dust 1997

a. Dust from rock drills, blasting, or handling rock. Fay b. In the quantity inhaled by workers, dust may be classified as dangerous, harmless, and borderline, although the classification is purely arbitrary. Silica is a dangerous dust and aluminum hydroxide is borderline. Lewis c. Scot. Calcined ironstone screenings. Standard, 2 d. See: coal dust mined volume In mine subsidence, the mined area multiplied by the mean thickness of the bed, or of that part of the bed that has been extracted. Briggs mine examiner See: fire boss mine expert See: mining engineer mine fan a. The main fan for a mine; normally situated at the surface. BS, 8 b. A radial- or axialflow ventilator. See also: fan; ventilation. Nelson mine fan signal system A system that indicates by electric light or electric audible signal, or both, the slowing down or stopping of a mine ventilating fan. mine feeder circuit A conductor or group of conductors, including feeder and sectionalizing switches or circuit breakers, installed in mine entries or gangways and extending to the limits set for permanent mine wiring, beyond which limits portable cables are used. mine fill See: hydraulic fill mine fire This very dangerous occurrence may arise as the result of spontaneous combustion, the ignition of timbers by gob fires, electric cable defects, or the heating and ignition of conveyor belts due to friction. Nelson mine fire truck 1998

Designed to fight underground fires in mining operations, this low slung railcar is equipped with a water supply and pressure equipment for its fire hoses. When a fire occurs, the car can be sped to the scene along existing rails. The truck is capable of delivering hundreds of gallons of water, depending upon the size and model used. Best, 1 mine foreman a. The person charged with the responsibility of the general supervision of the underground workings of a mine and the persons employed therein. In certain states, the mine foreman is designated as the mine manager. See also: foreman b. Generally used to designate that company representative in complete 24-h charge of underground workings and legally held responsible for the safety and welfare of all underground employees. The foreman is generally State certified for competency. BCI c. A deputy in metal mines. Nelson d. An official in charge of plant and associated labor on the surface, e.g., screen foreman. Nelson mine ground A stratum or group of strata containing layers of ironstone. minehead See: pithead mine head In a mine ventilation system, the cumulative energy consumption is called the mine head. A head is in reality a pressure difference, determined in accordance with Bernoulli's principle. Hartman, 1 mine hoist A device for raising or lowering ore, rock, or coal from a mine and for lowering and raising workers and supplies. See also: hoist mine hoist control This mechanism is designed to prevent accidents in mine cages caused by overspeeding in hoisting and lowering. It also prevents hoisting or lowering beyond the limits for which the controller is set. On electric hoists, it can apply a brake in case of power failure and may regulate brake speed in the event of an emergency stop. Best, 1 mine inspector

1999

a. Person who checks mines to determine the safety condition of working areas, equipment, ventilation, and electricity, and to detect fire and dust hazards. Webster 3rd b. Generally used as denoting the State mine inspector as contrasted to the Federal mine inspector. See also: inspector mine iron Pig iron made entirely from ore; distinguished from cinder pig. Standard, 2 mine jeep A special electrically driven car for underground transportation of officials, inspectors, repair, maintenance, and surveying crews and rescue workers. mine lamp Battery operated lamp; may be attached to a miner's cap to provide illumination in poorly lighted mine areas. Lamps are designed to focus on working areas when attached. A unit consists of a rechargeable battery, bulb, reflector, wires, etc. Mine lamps may be purchased outright or leased. Models include cap lamps, hand lamps, and trip lamps. Best, 1 mine land reclamation The process of transforming mine land into usable conditions; e.g., with regard to residential, recreational, agricultural, commercial or forestry purposes. SME, 1 mine locomotive A low, heavy, haulage engine, designed for underground operation; usually propelled by electricity, gasoline, or compressed air. See also: electric mine locomotive; trolley locomotive. Fay mine mason Mineworker who lines the galleries and other rooms with masonry, works on the repair of mine supports, and builds ventilation doors and dams. Stoces mine motorman See: motorman mine opening See: opening 2000

mine power center A mine power center is a combined transformer and distribution unit complete within a metal enclosure, usually of explosion-proof design, from which one or more low-voltage power circuits are taken. mine prop Section of wood, generally part of a small tree trunk, used for holding up rock in the roof of a mine. Mersereau, 2 miner a. In anthracite and bituminous coal mining, one who performs the complete set of duties involved in driving underground openings to extract coal, slate, and rock, with a hand or machine drill, into which explosives are charged and set off to break up the mass. Also called coal digger; coal getter; coal hewer; digger; faceman. DOT b. In nonmetal mining, such as limestone, one who drills holes in working face of a limestone mine, and inserts and sets off charges of explosives in holes. May be designated as development miner when working in new areas to drive drifts, shafts, sumps, and entry areas into stopes; high-raise miner when working in vertical areas to gain access into new development areas; or stope miner when working in horizontal openings in limestone strata. Syn: stope miner c. In mining, one who performs the complete set of duties involved in driving underground openings to extract ore or rock: drills holes in working face of ore or rock, with a hand or machine drill; inserts explosives in drill holes and sets them off to break up the mass; shovels ore or rock into mine cars or onto a conveyor, and pushes mine cars to haulageways, where they are hauled by draft animals, mine locomotive (motor), or haulage cable to the surface, or to the shaft bottom for hoisting; and installs timbering to support the walls and roof, or for chutes or staging. Due to standardization of mining methods and development of mining machinery, these jobs may be performed by several workers. Where conditions are favorable, loading is done by machine. DOT d. One who mines; such as (1) a person engaged in the business or occupation of getting ore, coal, precious substances, or other natural substances out of the earth; (2) a machine for automatic mining (as of coal); and (3) a worker on the construction of underground tunnels and shafts (as for roads, railways, waterways). Webster 3rd e. A worker in a coal mine who is paid a certain price for each ton of coal he or she digs or blasts from the solid seam, as distinguished from the laborer who loads the cars, etc. The miner's helpers load the coal; they are also called laborers. Fay f. Includes all laborers who work in a mine, whether digging coal, timbering, or making places safe. Fay g. Loosely used to designate all underground employees; technically, and in many cases legally, only those who have served an apprenticeship as helpers or those who are State licensed as miners. BCI h. A worker who cuts coal in a breast or chamber by contract; the highest-skilled worker of a colliery. Korson i. One who mines; a digger for metals and other minerals; is not necessarily a mechanic, handcraftsman, or 2001

artisan, and the term imports neither learning nor skill. Ricketts j. Abbrev. for continuous miner. Nelson mineragraphy See: ore microscopy mineral a. A naturally occurring inorganic element or compound having an orderly internal structure and characteristic chemical composition, crystal form, and physical properties. CF: metallic b. In miner's phraseology, ore. See also: ore c. See: mineral species; mineral series; mineral group. d. Any natural resource extracted from the earth for human use; e.g., ores, salts, coal, or petroleum. e. In flotation, valuable mineral constituents of ore as opposed to gangue minerals. f. Any inorganic plant or animal nutrient. g. Any member of the mineral kingdom as opposed to the animal and plant kingdoms. mineral acre The full mineral interest in 1 acre (0.4 ha) of land. Williams mineral adipocire See: hatchettite mineral assessment a. The process of appraisal of identified and undiscovered mineral resources within some specified region, and the product of that appraisal. Barton b. The estimation of mineral endowment, meaning the number of deposits or the tonnage of metal that occurs in the region, given some minimum size of accumulation (deposit), minimum concentration (grade), and maximum depth of occurrence. Syn: predictive metallogeny mineral association A group of minerals found together in a rock, esp. in a sedimentary rock. AGI mineral belt An elongated region of mineralization; an area containing several mineral deposits. AGI mineral blossom Drusy quartz. Fay 2002

mineral bruto Sp. Raw ore. Hess mineral caoutchouc See: elaterite; helenite. mineral carbonatado Sp. Carbonate ore. Hess mineral charcoal a. A pulverulent, lusterless substance, showing distinct vegetal structure, and containing a high percentage of carbon with little hydrogen and oxygen, occurring in thin layers in bituminous coal. Called mother of coal by miners. Fay b. Another name for fusain. BS, 4 mineral claim A mining claim. Mathews mineral cleavage Mineral breakage along specific crystallographic planes in all specimens due to fewer or weaker chemical bonds in those directions. CF: mineral parting mineral deed A conveyance of an interest in the minerals in, on, or under a described tract of land. The grantee is given operating rights on the land; easements of access to the minerals are normally implied unless expressly negated. Williams mineral de fusion propia Sp. Self-fluxing ore. Hess mineral deposit a. A mass of naturally occurring mineral material; e.g., metal ores or nonmetallic minerals, usually of economic value, without regard to mode of origin. Accumulations of coal and petroleum may or may not be included; usage should be defined in context. Syn: orebody b. A mineral occurrence of sufficient size and grade that it might, under 2003

favorable circumstances, be considered to have economic potential. See also: ore; ore deposit. USGS, 1 mineral deposit model The systematically arranged information describing the essential attributes (properties) of a class of mineral deposits. The model may be empirical (descriptive), in which instance the various attributes are recognized as essential even though their relationships are unknown; or it may be theoretical (genetic), in which instance the attributes are interrelated through some fundamental concept. See also: model SME, 1 mineral dresser A machine for trimming or dressing mineralogical specimens. Standard, 2 mineral dressing a. Physical and chemical concentration of raw ore into a product from which a metal can be recovered at a profit. ASM, 1 b. Treatment of natural ores or partly processed products derived from such ores in order to segregate or upgrade some or all of their valuable constituents, and/or remove those not desired by an industrial user. Mineral dressing processes are applied to industrial wastes to retrieve useful byproducts. See also: mineral processing; ore dressing. Pryor, 2 mineral economics Study and application of the technical and administrative processes used in management, control, and finance connected with the discovery, development, exploitation, and marketing of minerals. Pryor, 3 mineral endowment The physical aggregate of mineral occurrences in a region above some lower cutoff. Shanz mineral engineering Term covers a wide field in which many resources of modern science and engineering are used in discovery, development, exploitation, and use of natural mineral deposits. Pryor, 3 mineral entry The filing of a claim for public land to obtain the right to any minerals it may contain. Craigie 2004

mineral facies See: metamorphic facies mineral fat See: ozocerite mineral fiber a. Fibrous mineral whose fibers are longer than 5 mu m and with an aspect ratio (length over width) equal to or greater than 3:1 as determined by the membrane filter method at 400X to 500X magnification (4-mm objective) phase contrast illumination. ACGIH, 1 b. The smallest elongated crystalline unit that can be separated from a bundle or appears to have grown individually in that shape, and that exhibits a resemblance to organic fibers. Campbell mineral field Scot. A tract of country in which workable minerals are found; a mineral leasehold. mineral filler A finely pulverized inert mineral or rock that is included in a manufactured product-e.g., paper, rubber, and plastics--to impart certain useful properties, such as hardness, smoothness, or strength. Common mineral fillers include asbestos, kaolin, and talc. AGI mineral fuel Coal or petroleum. See also: fossil fuel mineral group Two or more mineral species having identical or closely related structures; e.g., hematite group or zeolite group. See also: mineral mineral interests Mineral interests in land means all the minerals beneath the surface. Such interests are a part of the realty, and the estate in them is subject to the ordinary rules of law governing the title to real property. Ricketts mineral inventory

2005

An accounting of the mineral reserves and resources contained in known mineral deposits including inactive mines, operating mines, and undeveloped sites. Shanz mineralization The process or processes by which a mineral or minerals are introduced into a rock, resulting in a valuable or potentially valuable deposit. It is a general term, incorporating various types; e.g., fissure filling, impregnation, and replacement. AGI mineralize To convert to a mineral substance; to impregnate with mineral material. The term is applied to the processes of ore formation and also to the process of fossilization. AGI mineralized bubble In flotation, one of the bubbles that rise from the pulp loaded with particles of desired mineral. Pryor, 3 mineralizer See: ore-forming fluid; geologic mineralizer. mineralizing agent See: ore-forming fluid; geologic mineralizer. mineral land Land that is worth more for mining than for agriculture. The fact that the land contains some gold or silver would not constitute it mineral land if the gold and silver did not exist in sufficient quantities to pay to work. Land not mineral in character is subject to entry and patent as a homestead, however limited its value for agricultural purposes. CF: stone land Mineral Lands and Mining The leasable minerals include oil, gas, sodium, potash, phosphate, coal, and all minerals within acquired lands. Acquisition is by application for a Government lease and permits to mine or explore after lease issuance. SME, 1 mineral lease See: mining lease 2006

mineral occurrence a. The presence of useful minerals or rocks in an area under examination. Shanz b. A concentration of a mineral (usually, but not necessarily, considered in terms of some commodity, such as copper, barite, or gold) that is considered to be valuable or that is of scientific or technical interest. In rare instances (such as titanium in a rutile-bearing black sand), the concentration of the commodity might be less than its average crustal abundance. USGS, 1 mineralogical guide A mineral that is present near an orebody and is related to the processes of ore deposition. Guides help locate ore and may constitute targets for ore search. mineralogical phase rule Any of several modifications of the fundamental Gibbs phase rule, taking into account the number of degrees of freedom consumed by the fixing of physical-chemical variables in the natural environment. The most famous such rule, that of Goldschmidt, assumes that two variables (taken as pressure and temperature) are fixed externally and that consequently the number of phases (minerals) in a system (rock) will not generally exceed the number of components. The Korzhinskii-Thompson version takes into account the external imposition of chemical potentials of perfectly mobile components, and thereby reduces the maximum expectable number of minerals in a given rock to the number of inert components. Syn: Goldschmidt's phase rule mineralogist Person who studies the formation, properties, use, occurrence, composition, and classification of minerals; a geologist specialized in mineralogy. Syn: oryctologist (obsolete) mineralography See: ore microscopy mineralogy The study of minerals: formation, occurrence, use, properties, composition, and classification. Adj. mineralogic, mineralogical. mineraloid

2007

Minerallike constituent of rocks which is not definite enough in chemical composition or in physical properties to be considered a mineral. Hydrocarbons, volcanic glass, and palagonite are classed as mineraloids. Hess mineral paint See: mineral pigment mineral parting Mineral breakage along specific crystallographic planes in some specimens due to twinning, exsolution lamellae, or chemical alteration. See also: parting mineral pigment A mineral material used to give color, opacity, or body to a paint, stucco, plaster, or similar material. See also: ocher; sienna; umber. mineral processing The dry and wet crushing and grinding of ore or other mineral-bearing products for the purpose of raising concentrate grade; removal of waste and unwanted or deleterious substances from an otherwise useful product; separation into distinct species of mixed minerals; chemical attack and dissolution of selected values. Among the methods used are hand sorting (including radioactivation and fluorescence); dense media separation; screening and classification; gravity treatment with jigs, shaking tables, Humphries spirals, Frue vanners, or sluices; magnetic separation at low or high intensity; leach treatment, perhaps using pressure and heat; and (universally) froth flotation. Also called beneficiation; ore dressing; mineral dressing. mineral province A region in which the source, age, and regional distribution of a complex of minerals in a sediment are related. Schieferdecker mineral reserves See: reserves mineral resin Any of a group of resinous, usually fossilized, mineral hydrocarbon deposits; e.g., bitumen and asphalt. See also: resin mineral right 2008

The ownership of the minerals under a given surface, with the right to enter thereon, mine, and remove them. It may be separated from the surface ownership, but, if not so separated by distinct conveyance, the latter includes it. mineral rubber See: uintaite mineral salt Mined rock salt, halite. mineral sequence The sequential order of mineral deposition during formation of an ore deposit. CF: paragenesis mineral series Mineral species showing continuous variation in their properties with change in composition. A series may be complete; e.g., tennantite-tetrahedrite, or partial; e.g., iron replacing zinc in sphalerite. Syn: crystal solution; solid solution. See also: mineral mineral species a. Any mineral that can be distinguished from all other minerals by current determinative methods. Stokes b. A naturally occurring homogeneous substance of inorganic origin, in chemical composition either definite or ranging between certain limits, and possessing characteristic physical properties and usually a crystalline structure. See also: mineral mineral spring A spring whose water contains enough mineral matter to give it a definite taste, in comparison to ordinary drinking water, esp. if the taste is unpleasant or if the water is regarded as having therapeutic value. This type of spring is often described in terms of its principal characteristic constituent; e.g., salt spring. AGI minerals separation process A flotation process based on surface-tension phenomena, accelerated by means of addition to the pulp of small quantities of oil and air in minute subdivision. Only about 0.1% oil is added, and the pulp is violently agitated for 1 to 10 min. Innumerable small bubbles of air are thus mechanically introduced, which join the oil-coated particles. These are then removed in a spitzkasten. Exposure to the air after this treatment then 2009

aerates any mineral that has not already taken up its oil film, after which a second spitzkasten treatment removes this. An early name for froth flotation. Liddell; Pryor, 3 mineral stabilizer A fine, water-insoluble, inorganic material, used in admixture with solid or semisolid bituminous materials. ASTM mineral streaking In metamorphic rocks, lineation of grains of a mineral. Syn: streaking AGI mineral tallow See: hatchettine; hatchettite. Also called mountain tallow. mineral tar a. Tar derived from various bituminous minerals, such as coal, shale, peat, etc. Shale tar. Syn: mountain tar b. See: maltha; pittasphalt. mineral turquoise Term to distinguish true turquoise from odonotolite (bone turquoise). mineral variety Specimens of a mineral species with distinctive physical properties due to: (1) specific history; e.g., Iceland spar, a coarsely crystalline variety of calcite of optical grade, or (2) small chemical variation; e.g., amalgam, a mercurian variety of native silver. mineral vein See: vein mineral water Water that contains an unusually high percentage of some mineral substance that gives the water a distinctive taste and sometimes other properties. Considered to be beneficial in the treatment of various ailments. Also called spa water. Cooper mineral wax See: ozocerite 2010

mineral wedging A form of chemical weathering resulting in the formation of new minerals that have greater aggregate volumes than the old ones. These expanding minerals then act as wedges to split adjacent minerals and rocks apart. AGI mineral wool A substance outwardly resembling wool, presenting a mass of fine interlaced filaments. It is made by subjecting furnace slag or certain rocks, while molten, to a strong blast. Being both insect proof and fireproof, it forms a desirable packing for walls, a covering for steam boilers, etc. Also called mineral cotton, silicate cotton, and slag wool. Syn: glass wool mineral zoning See: zoning of ore deposits mine refuse a. Waste material in the raw coal that has been removed in a cleaning or preparation plant. b. Notably used to describe colliery rejects; also called tailings. Pryor, 3 mine rescue apparatus The rescuing of miners overcome by a mine fire, or trapped in workings by an explosion, necessitates the use of apparatus that will enable the rescue team to work in irrespirable or poisonous gases. The equipment used is known as mine rescue apparatus. See also: rescue apparatus Nelson mine rescue car One of a number of railway cars specially equipped with mine rescue apparatus, safety lamps, first-aid supplies, and other materials, maintained by the Mine Safety and Health Administration in various sections of the United States. These cars serve as movable stations for the training of miners in the use of mine rescue apparatus, and in first aid to the injured; as centers for the promotion of mine safety; as emergency stations for assisting at mine fires, explosions, or other disasters. Similar cars are maintained by a number of mining companies. Syn: mine-safety car mine rescue crew A crew consisting usually of five people who are thoroughly trained in the use of mine rescue apparatus, and are capable of wearing it in rescue or recovery work in a mine following an explosion, or to combat a mine fire. Fay 2011

mine rescue lamp A name given to a particular type of electric safety hand lamp used in rescue operations. It is equipped with a lens for concentrating or diffusing the light beam as occasion may require. Fay mine resistance a. The resistance offered by a mine to the passage of an air current. The mine resistance is due to the friction of the air rubbing along the sides, top, and bottom of the air passages. To overcome this friction, the total ventilating pressure must be applied against the airway and this pressure must be equal to the mine resistance. Mine resistance is caused by the dragging of the air against the mine surfaces and other obstructions. The rougher the mine surfaces and the more the obstructions, the greater the resistance to the flow of air. Kentucky b. Includes any natural ventilation effect present and is calculated from air volume and total pressure. The standard practice in the United Kingdom is to express the resistance of a mine in square feet of equivalent orifice. Roberts, 1 mine road Any mine track used for general haulage. Fay mine roadway area measurement See: tape-triangulation method mine rock A more or less altered rock found in ore channels. Gangue. minerocoenology The study of mineral associations in the broadest sense, such as the correlation of igneous rocks or magmatic provinces with their ore deposits. AGI minerogenesis The origin and growth of minerals. Challinor minerogenetic epoch See: metallogenetic epoch minerogenetic province 2012

a. An area in which mineralization has been active at one or more periods. If the mineralization has been chiefly metalliferous, the term metallogenetic is applicable. Syn: metallogenetic province b. A region characterized by relatively abundant mineralization dominantly of one type. AGI miners The row of drill holes in a tunnel face, located below the breaking-down holes. Stauffer miner's bar An iron bar pointed at one end, chisel-edged at the other, used in coal mining. Standard, 2 miner's box A wood or iron box located in or near the working place of a miner in which tools, supplies, etc. are kept. Required by law in some States. Fay miner's dial An underground surveying instrument for measuring and setting out angles and determining magnetic north. Syn: mine dial miner's dip needle A portable form of dip needle used for indicating the presence of magnetic ores. Also called dipping compass. CTD miner's electric cap lamp a. A lamp for mounting on a miner's cap and receiving electric energy through a cord which connects the lamp with a small battery. b. An electric lamp designed for fixing to a miner's helmet. Its principal parts are: (1) the battery, either lead acid or alkaline; (2) the headpiece, of plastic or aluminum alloy, with switch; and (3) a length of twin-cord cable covered with tough rubber or with neoprene--a fire- and acid-resisting substitute. The lead-acid lamps commonly use either a 4-V, 1.0-A bulb with a light output of about 47.5 lumens or else a 4-V, 0.8-A bulb of 38 lumens output. The headpiece is equipped with an auxiliary, 4 V, 0.46-A bulb. Nelson miner's hammer A hammer for breaking ore. Standard, 2 miner's hand lamp 2013

A self-contained mine lamp with a handle for convenience in carrying. miner's hard cap Cap made of rigid, strong materials such as vulcanized fiber, glass fiber or plastic, which protects a worker from injury caused by falling objects, large chips, or by striking the head against projecting materials. The cap has a cradle to cushion the shock of blows and a sweat band to absorb perspiration; it is water resistant and nonconductive. A front visor shields the face and eyes from overhead glare, and makes the cap suitable for wear in close, confined spaces where a full brim might interfere. Best, 1 miner's helmet A hat designed for miners to provide head protection and for holding the cap lamp. See also: miner's hard cap miner's horn A horn or metal spoon used to collect ore particles in gold washing. Standard, 2 miner's inch a. The rate of flow of water through an aperture 1 in (2.54 cm) square under a given pressure, generally taken to be that of water standing 6 in (15.2 cm) above the top of the aperture. It is not a universal value but is fixed by statute in several States. A commonly accepted rate is 90 ft3 /h (2.5 m3 /h), or 1-1/2 ft3 /min (0.042 m3 /min). CF: sluice head b. A unit used in California, around 1900, for measuring water flow in hydraulicking. It represented the outflow from a 1-in2 (6.5-cm2 ) opening in the side of a box. It varied from 2,000 to 2,600 ft3 /per day (56.6 to 73.6 m3 /d), according to the height of water, etc. Nelson c. The term is not definite without specification of the head or pressure. It has no fixed meaning and in one locality sometimes is a very different quantity according to miner's measurement in another locality. It has been defined as the amount of water that will pass in 24 hours through an opening 1 in (2.54 cm) square under a head of 6 in. Ricketts miner's inch day Flow of 1 miner's inch for 24 hours. Mining miner's lamp a. In nongassy mines, acetylene lamps and various electric lamps; in gassy mines, approved flame safety lamps, electric hand or cap lamps. Nelson b. Any one of a variety of lamps used by a miner to furnish light; e.g., oil lamps, carbide lamps, flame safety lamps, electric cap lamps, etc. Fay 2014

miner's lung See: pneumoconiosis miner's needle A long, slender, tapering, metal rod left in a hole when tamping and afterwards withdrawn, to provide a passage, to the blasting charge, for the squib. Fay miners' nystagmus An occupational disease that occurs among coal miners, usually those of middle age or elderly, who have worked for a period of 25 to 30 years underground. Its physical symptoms consist of difficulty of seeing in the dark or in poor light, excessive sensitivity to and intolerance of glare, and a rhythmic oscillation of the eyeballs. As a result of these oscillations, there may be apparent movement of the objects looked at and defective visual acuity. Associated with these ocular symptoms are other general disorders, such as headaches and dizziness, particularly after stooping or bending, and the development of psychoneurotic symptoms is common in the later stages of the disease. If the disease is not checked, the nervous disorders may become so severe as to render the miner totally disabled. Roberts, 2 miners' oil An oil, producing little smoke, used in miners' wick-fed open lamps. Fay miner's pan See: pan miner's pick See: pick miners' rescue party A team of trained mine rescue workers, from five to eight strong; they operate after explosions, and during and after mine fires. See also: rescue team miner's right a. An annual permit from the Government to occupy and work mineral land. b. In California, the right of a miner to dig for precious metals on public lands, occupied by another for agricultural purposes. 2015

miners' rules Rules and regulations proclaimed by the miners of any district relating to the location, recording, and the work necessary to hold possession of a mining claim. It was the miners' rules of the early days of the mining industry that were the basis of the present laws. The local mining laws and regulations of 1849 and later are given in vol. 14, 10th Census of the United States, 1880, compiled by Clarence King. Fay miner's self-rescuer A small form of breathing apparatus for protection against carbon monoxide, worn on a miner's belt. It consists of a canister with a mouthpiece directly attached to it. The wearer breathes through the mouth, the nose being closed by a clip. The canister contains a layer of fused calcium chloride to absorb the water vapor in the air which destroys the efficiency of the other chemical called hopcalite. The self-rescuer affords protection for 30 min, so that miners surviving an explosion may walk out through a mine atmosphere that contains sufficient oxygen but also a fatal percentage of carbon monoxide. miner's wedge A metallic wedge or plug for splitting off masses of coal. Standard, 2 miner's weight The term used in a coal mining lease as the basis for the price per ton to be paid for mining. It is not a fixed, unvarying quantity of mine-run material, but is such a quantity of material as operators and miners may, from time to time, agree as being necessary or sufficent to produce a ton of prepared coal. Ricketts mine run a. The entire unscreened output of a mine. Also called run-of-mine. Zern b. The product of the mines before being sized and cleaned. Hudson c. A product of common or average grade. Webster 3rd mine-run coal Ungraded coal of mixed sizes as it comes from the mine. Hess mine-run mica See: book mica mine-safety car 2016

See: mine rescue car mine signal system Designed esp. for use in mines, these signal lights at individual switches immediately indicate to the motorman whether or not it is safe to proceed. Green and amber lights work automatically with the movement of the switches. May be used with locally controlled switches, or with those operated by a central dispatcher. Best, 1 mine skip Skip used to bring mined material to the surface of a mine shaft; manufactured in various sizes and designs for both vertical and incline shafts, including tipover models and bottom door dump models. Best, 1 mine static head The energy consumed in the ventilation system to overcome all flow head losses. It includes all the decreases in total head (supplied from static head) that occur between the entrance and discharge of the system. Hartman, 2 mine superintendent A mine manager or group manager. Nelson mine surveyor The official at a mine who periodically surveys the mine workings and prepares plans for the manager. Formerly, the mine surveyor carried out many of the duties now performed by the planning department. See: surveyor; mine. Nelson mine tin Tin obtained from veins or lodes, as distinguished from stream tin. mine tons Gross tonnage of ore including waste and unpayable material. Beerman mine total head The sum of all energy losses in the ventilation system. Numerically, it is the total of the mine static and velocity heads. See also: total ventilating pressure; ventilating pressure. Hartman, 2 2017

mine track device One of a variety of track devices to provide maximum safety for haulage trains in mines. Designed to be used in conjunction with switch signals, these devices include electric switch throwers operated by hand contractors on a copper plate, overhead hand controllers, remote control, or trolley contractors. Other safety equipment includes mechanical switches for gaseous or hot mines, derailing switches for trains out of control, and automatic mine-door opening devices. Best, 1 mine tractor A trackless, self-propelled vehicle used to transport equipment and supplies and for general service work. See also: tractor mine valuation Properly weighing the financial considerations to place a present value on mineral reserves. Nelson mine velocity head The velocity head at the discharge of the ventilation system. Throughout the system, the velocity head changes with each change in duct area or number and is a function only of the velocity of airflow. It is not a head loss. The velocity head for the system must technically be counted a loss, because the kinetic energy of the air is discharged to the atmosphere and wasted. Therefore, it must be considered a loss to the system in determining overall energy loss. Hartman, 2 mine ventilating fan A motor-driven disk, propeller, or wheel for blowing (or exhausting) air to provide ventilation of a mine. See also: ventilation Syn: ventilating fan mine ventilation auxiliary fan A small fan installed underground for ventilating coal faces or hard rock headings that are not adequately ventilated by the air current produced by the mine-ventilation fan. An auxiliary fan is usually from 0.5 to 1.0 m in diameter. It is driven by compressed air or electricity. The auxiliary fan can be used to force or exhaust ventilate the workplace. mine-ventilation fan A machine possessing rotating air-moving blades to exhaust or push the air volume necessary to ventilate mine workings. See also: aerofoil-vane fan; axial-flow fan. 2018

mine-ventilation fan characteristics The behavior of a fan under various conditions cannot be expressed in simple mathematics but may be shown graphically by suitable curves, known as the fan's characteristic curves or characteristics. The curves of interest are generally head versus air quantity, power versus air quantity, and efficiency versus air quantity. Hartman, 2 mine ventilation system An arrangement of connecting airways in a mine together with the pressure sources and control devices that produce and govern airflow. Hartman, 2 mine water Water pumped from mines usually contains impurities, some of which are in suspension, but the majority, which are soluble, cause the water to be hard. The water often contains corrosive agents, such as acids or alkalis. Cooper mine wireman See: wireman mineworks Ancient subterranean passages or mine excavations. Standard, 2 mingled ground Mixed clay and sand or rock. Arkell minguzzite A monoclinic mineral, K3 Fe(C2 O4 )3 .3H2 O ; green; an oxalate. miniature current meter A device used to measure the passage of current past a probe on each blade of a propeller type, or each cup of a price-type meter by detecting the change of electrical resistance between that probe and a distant electrode. Hunt minimum deviation A method for measuring the refractive index of a prism or a liquid in a hollow prism by determining the minimum deflected angle of a light beam. 2019

minimum firing current As applied to electric blasting caps, the limit below which firing will not occur. Fraenkel minimum ignition energy The minimum ignition energy required for the ignition of a particular flammable mixture at a specified temperature and pressure. Van Dolah minimum oxygen content The U.S. Mine Safety and Health Administration and other recognized safety and health agencies recommend 19.5% as the minimum oxygen content allowable. Hartman, 1 minimum product firing temperature The lowest product temperature at which an explosive or explosive unit is approved for use. CFR, 4 mining The science, technique, and business of mineral discovery and exploitation. Strictly, the word connotes underground work directed to severance and treatment of ore or associated rock. Practically, it includes opencast work, quarrying, alluvial dredging, and combined operations, including surface and underground attack and ore treatment. CF: mining geology; mining engineering. Pryor, 3 mining advancing A method of mining by which the ore or coal is mined as the excavation advances from the shaft or main opening. CF: mining retreating Fay mining camp a. A colony of miners settled temporarily near a mine or a goldfield. Standard, 2 b. A term loosely applied to any mining town. Fay mining captain Person in charge of mining operations. Craigie mining case A frame of a shaft, or gallery, composed of four pieces of plank. Standard, 2 2020

mining claim a. That portion of the public mineral lands that a miner, for mining purposes, takes hold of and possesses in accordance with mining laws. b. A mining claim is a parcel of land containing valuable minerals in the soil or rock. A location is the act of appropriating such a parcel of land according to law or to certain established rules. See also: claim; placer claim; location. c. In the General Mining Law of 1872, that portion of a vein or lode and of the adjoining surface, or of the surface and subjacent material to which a claimant has acquired the right of possession by virtue of a compliance with such statute and the local laws and rules of the district within which the location may be situated. Independent of acts of the U.S. Congress providing a mode for the acquisition of title to the mineral lands of the United States, the term has always been applied to a portion of such lands to which the right of exclusive possession and enjoyment by a private person or persons, has been asserted by actual occupation, and compliance with the mining laws and regulations. Syn: holding Ricketts d. Distinction between mining claim and location is that they are not always synonymous and may often mean different things; a mining claim may refer to a parcel of land containing valuable mineral in its soil or rock, while location is the act of appropriating such land according to certain established rules. A mining claim may include as many adjoining locations as the locator may make or purchase, and the ground covered by all, though constituting what is claimed for mining purposes, will constitute a mining claim and will be so designated. Ricketts e. Title issued by the Government concerned to an individual or group, which grants that individual or group the right to exploit mineral wealth in a specified area by approved methods in accordance with the ruling laws and regulations. Pryor, 3 f. A claim on mineral lands. AGI mining compass An instrument giving qualitative indications of anomalies in the magnetic field. Schieferdecker mining dial See: dial mining disaster An accident in a mine in which a large number of people are killed. See also: major mine disaster mining disease See also: anthracosis; infective jaundice; nystagmus; pneumoconiosis; silicosis; simple silicosis. 2021

mining district A section of country usually designated by name, having described or understood boundaries within which minerals are found and worked under rules and regulations prescribed by the miners therein. There is no limit to its territorial extent and its boundaries may be changed if vested rights are not thereby interfered with. Ricketts mining ditch A ditch for conducting water used in mining. CF: mining sluice Craigie mining engineer a. A person qualified by education, training, and experience in mining engineering. Nelson b. If qualified and of standing in the profession, a trained engineer with knowledge of the science, economics, and arts of mineral location, extraction, concentration and sale, and the administrative and financial problems of practical importance in connection with the profitable conduct of mining. Usually a specialist in one or more branches of work. Activities may include prospecting, surveying, sampling and valuation, technical underground management, milling, assaying, ventilation control, layout of workings and plant, geological examination, and company administration. Pryor, 3 c. One versed in, or one who follows, as a calling or profession, the business of mining engineering. Graduates of technical mining schools are given the degree of engineer of mines and authority to sign the letters E.M. after their names. mining engineering The planning and design of mines, taking into account economic, technical, and geologic factors; also supervision of the extraction, and sometimes the preliminary refinement, of the raw material. CF: mining; mining geology. AGI mining explosive One of the high explosives used for mining and quarrying. They can be divided into four main classes: gelatins; semigelatins; nitroglycerin powders, and non-nitroglycerin explosives, including water gels, emulsions, and ANFO. mining geology a. The study of geologic structures and particularly the modes of formation and occurrence of mineral deposits and their discovery. Syn: ore geology b. In coal mining, the study of: rock formations, particularly with reference to the Carboniferous System; the mode of formation of coal seams, their discovery and correlation. See also: geology Nelson c. The study of the geologic aspects of mineral deposits, with particular regard to problems associated with mining. CF: mining; mining engineering. AGI 2022

mining ground No land can be a mining claim unless based upon a location; otherwise it may be mining ground or a mine. For instance, the bed of a navigable river is not subject to mining location, but if mining is conducted thereon by dredging, it is mining ground; or, where land is covered by an agricultural patent and worked for its mineral deposits, it is mining ground and not a mining claim. Hence, land from which a mineral substance is obtained from the earth by the process of mining may, with propriety, be called mining ground or mining land. See also: claim; location. (Ricketts, 1943) mining hazard Any of the dangers peculiar to the winning and working of coal and minerals. These include collapse of ground, explosion of released gas, inundation by water, spontaneous combustion, inhalation of dust and poisonous gases, etc. Nelson mining head The mechanism on a continuous mining machine that breaks down the coal. mining lease A legal contract for the right to work a mine and extract the mineral or other valuable deposits from it under prescribed conditions of time, price, rental, or royalties. Syn: mineral lease mining locomotive A small locomotive for use in underground haulage, sometimes consisting of a car bearing a powerful electric motor, built very low and operated through a trolley. May also be operated by electricity from batteries. Standard, 2 mining machine A coal-cutting machine. Standard, 2 mining machine operator See: machine miner mining-machine-operator helper See: machine helper mining machine truck 2023

A truck used for transporting shortwall mining machines. Track-mounted trucks are necessarily limited in use to sections employing track. Crawler-type trucks are capable of transporting the cutting machine without need of track and without benefit of ropes. Jones, 1 mining method Any of the systems employed in the exploitation of coal seams and orebodies. The method adopted depends on a large number of factors, mainly, the quality, shape, size, and depth of the deposit; accessibility and capital available. See also: coal mining methods; metal mining; stoping methods. Nelson mining ore from top down See: top slicing and cover caving mining property Property, esp. land, valued for its mining possibilities. Craigie mining purposes The term "mining purposes" as used in connection with mill-site locations, is very comprehensive, and may include any reasonable use for mining purposes that the quartz lode mining claim may require for its proper working and development. This may be very little, or it may be a great deal. The locator of a quartz lode mining claim is required to do only $100 worth of work each year until obtaining a patent. Ricketts mining recorder In a mining camp, a person selected to keep a record of all mining claims and properties. Mathews mining retreating A process of mining by which the ore, or coal, is untouched until after all the gangways, etc., are driven, when the work of extraction begins at the boundary and progresses toward the shaft. CF: mining advancing Fay mining right Upon a specific piece of ground, a right to enter upon and occupy the ground for the purpose of working it, either by underground excavations or open workings, to obtain from it the mineral ores which may be deposited therein. Ricketts 2024

mining shield A cover or canopy developed by the U.S. Bureau of Mines for the protection of mine workers and machines at the face of a mechanized coal heading. Hydraulic rams telescope and steer the shield forward as the face advances. It enables continuous miners to operate with greater safety. Nelson mining sluice An artificial channel or passage for water used in mining. CF: mining ditch mining system Work, as it is commenced on the ground, is such that, if continued, will lead to a discovery and development of the veins or orebodies that are supposed to be in the claim, or, if these are known, that the work will facilitate the extraction of the ores and minerals. mining theodolite A theodolite having particular features of design that make it suitable as an underground surveying instrument; e.g., incorporating an arrangement for the centering movement to be above the foot screws. BS, 7 mining title A claim, exclusive prospecting license, concession, right, or lease. A grant under laws and mining regulations to a person or group of approved persons of the right to develop and exploit a properly delineated area for its mineral wealth. Pryor, 3 mining-type visibility meter An instrument to facilitate observation of the essential elements of visual tasks in coal mines. It is a brightness meter in which the comparison field is illuminated by a cap lamp headpiece attached outside the instrument. No internal electrical circuit exists other than that which connects the photocell to the microammeter and the meter can therefore be used anywhere in a safety-lamp mine without restrictions. Roberts, 2 mining under The act of digging under coal or in a soft strata in coal seams. mining width

2025

The minimum width necessary for the extraction of ore regardless of the actual width of ore-bearing rock. See also: stoping width minion The siftings of iron ore after calcination. Standard, 2 minium A tetragonal mineral, Pb3 O4 ; red; an alteration product of galena or cerussite. Syn: red lead minnesotaite A monoclinic mineral, (Fe,Mg)3 Si4 O10 (OH)2 ; talc-pyrophyllite group; in the banded iron formations of Minnesota. Syn: iron talc minor element a. Trace element or accessory element. See also: trace element b. Less commonly, any of the elements present in the range of 0.1% to 1%, between major elements in concentrations greater than 1% and trace elements in concentrations less than 0.1%, or occasionally less than 0.01%. minus sieve In powder metallurgy, the portion of a powder sample that passes through a standard sieve of specified number. Contrast with plus sieve. ASM, 1 minus sight See: foresight minus station Stakes or points on the far side of the zero point from which a job was originally laid out. Nichols, 1 minute of arc A unit of angular measure equal to the 60th part of a degree and containing 60 s of arc. Webster 3rd minyulite 2026

An orthorhombic mineral, KAl2 (PO4 )2 (OH,F).4H2 O ; in phosphate rock in Western Australia and South Australia. Miocene An epoch of the later Tertiary period, after the Oligocene and before the Pliocene; also, the corresponding worldwide series of rocks. It is considered to be a period when the Tertiary is designated as an era. AGI mirabilite A monoclinic mineral, Na2 SO4 .10H2 O ; one perfect cleavage; tastes cool, then saline and bitter; in evaporite deposits, where it is mined as Glauber salt, and as an efflorescence. Syn: Glauber salt mire Mud. mirror plane See: plane of symmetry mirror stone See: muscovite mischio marble A violet-red breccia from Serravezza, Italy. Also known as African breccia (breche Africaine). mischmetal A natural mixture of the rare-earth metals cerium, lanthanum, and didymium; e.g., the waste matter from monazite sand after the extraction of thoria may contain large quantities of ceria, lanthana, didymia, yttria, and other substances. This is reduced to the metallic state by converting the oxides to chlorides, and then recovering the metal by electrolysis. The material obtained is an alloy containing about 50% cerium and 45% lanthanum and didymium. Henderson misenite A monoclinic mineral, K2 SO4 .6KHSO4 (?) ; in silky white fibers at Cape Miseno, Italy. (Not mizzonite.) 2027

miser A tubular well-boring bit, having a valve at the bottom, and a screw for forcing the earth upward. Also spelled mizer. Standard, 2; Fay misfire An explosive charge in a drill hole that has partly or completely failed to explode as planned. Causes include unskilled charging; defective explosive, detonator, or fuse; broken electric circuit or--most dangerous--cutting off of part or all of the charge through lateral rock movement as other holes in the vicinity are fired. Stringent safety precautions cover procedure in minimizing these risks and in dealing with known or suspected misfires. A smoldering fuse may delay explosion, causing a hangfire, so return to workings after a suspected failure is necessary. Another main cause of accident is drilling into or dangerously near a socket--an apparently empty drill hole. See also: missed hole; hangfire. Pryor, 3 misfire hole See: missed hole mispickel See: arsenopyrite misplaced material a. In mineral processing, material, particularly screen products and tailings, that has been reported in the wrong section. Pryor, 3 b. Material wrongly included in the products of a sizing or density separation; i.e., material that has been included in the lower size or specific gravity product but which itself has a size or specific gravity above that of the cut point, or vice versa. Its weight may be expressed as a percentage of the product or of the feed. Also called tramps (undesirable usage). BS, 5 c. In sizing and screening, undersize contained in the overflow, or oversize contained in the underflow. BS, 5 d. In cleaning, material of specific gravity lower than the separation density that has been included in the high density product, or material of specific gravity higher than the separation density that has been included in the low density product. BS, 5 missed hole A drill hole charged with explosives, in which all or part of the explosive has failed to detonate. Syn: misfire; misfire hole. Fraenkel missed round 2028

A round in which all or part of the explosive has failed to detonate. Fraenkel Mississippian A period of the Paleozoic era (after the Devonian and before the Pennsylvanian), thought to have covered the span of time between 345 and 320 million years ago; also, the corresponding system of rocks. It is named after the Mississippi River valley, in which there are good exposures of rocks of this age. It is the approximate equivalent of the Lower Carboniferous of European usage. AGI misy An old term for copiapite and related minerals. Mitchell system for underhand quarrying of panel cores See: underhand stoping miter gear See: bevel gear mitridaite A monoclinic mineral, Ca2 Fe3 (PO4 )3 O2 .3H2 O ; forms red crystals, green stains in granite pegmatites. M.I.T. sampler A single-tube, drive-type, soil-sampling barrel esp. adapted to sampling deposits of plastic clay where a minimum 5-in (12.7-cm) diameter sample is required. A loop or snare of piano wire is inserted in a groove inside the cutting shoe with the free end of the wire extending through a slot on the side of the sampler to the surface. When pulled, the wire cuts the sample off at the bottom of the cutting shoe. Long mitscherlichite A tetragonal mineral, K2 CuCl4 .2H2 O ; greenish blue. mix-crystal See: solid solution mixed 2029

Drill diamonds ranging from 23 to 80 per carat in size. Long mixed blast process A modification of the basic Bessemer process in which all the nitrogen is removed from the blast, it being made up of a mixture of oxygen and carbon dioxide or oxygen and superheated steam. The oxygen and superheated steam blast is claimed to be the more efficient, the final nitrogen content of the metal being brought to a mean level of 0.0028%. Osborne mixed cements A product obtained by mixing, or blending, either portland, natural, or pozzolana cement with one another or with other inert substances. Zern mixed crystal See: solid solution mixed dust Dust prepared for testing in a mine by mixing coal dust and inert dust in predetermined proportions. The mixture may also contain water, and different sizes of coal dust may be mixed to produce some desired intermediate size. Rice, 2 mixed explosion Occurs when both combustible gases and coal dust are present below their lower limits, but in combination produce sufficient heat of combustion to propagate an explosion. Sinclair, 1 mixed explosive Explosive consisting of an intimate mechanical mixture of substances which consume and generate oxygen but are not in themselves explosive. Inorganic nitrates, chlorates, and perchlorates. Most important is ammonium nitrate. Fraenkel mixed face In tunneling, digging in dirt and rock in the same heading at the same time. Nichols, 1 mixed-feed kiln Upright lime kiln in which the fuel (coal) is mixed and burned with the limestone charge. Mersereau, 2 2030

mixed-flow fan A mine fan in which the flow is both radial and axial. The Schicht fan is of this type and has the advantage that it can produce a high water gage with a single stage. This fan, however, is not well suited to mines where a large change in equivalent orifice may occur. CF: axial-flow fan; radial-flow fan. Nelson mixed-flow turbine An inward flow, reaction-type water turbine, in which the runner vanes are so shaped that they are acted on by the water pressure both axially and radially. Hammond mixed-layer mica a. See: clay mineral b. Layered silicates, generally of the smectite group, in which different layered mineral species are stacked in an ordered or random fashion. mixed-layer mineral A mineral whose structure consists of alternating layers of clay minerals and/or mica minerals; e.g. chlorite, made up of alternating biotite and brucite sheets. AGI mixed ore Ore containing both oxidized and unoxidized minerals. See also: oxidized ore; sulfide ore. Nelson mixer a. An apparatus used to thoroughly mix drilling fluid water with drilling ingredients. May be cement, mud, or lost circulation materials. Also called atomizer; mud mixer. Long b. See: agitator mixer cone A funnel-shaped hopper attached to the body of a mud mixer into and by means of which the dry, powdered, drill-mud and/or cement ingredients are fed into the mud mixer. Long mix-house person One who mixes sintered lead or zinc ore with such materials as pulverized coal and coke, salt, skimmings, water, and chemical solutions preparatory to smelting. Also called mixer operator. DOT mixing 2031

a. In powder metallurgy, the thorough intermingling of powders of two or more different materials (not blending). ASM, 1 b. An instrumentation technique used in seismograph recording in which a certain portion of the energy from each amplifier channel is fed to the adjacent channels, giving results somewhat analogous to those obtained from the use of multiple geophones to attenuate noise. AGI mixing pit A pit in which drill mud is mixed and stored until the mud is cured and needed for use as a drill circulation fluid. Long mix-in-place A common soil stabilization method in which the soil on the site is first pulverized, then mixed with an admixture or stabilizing agent, compacted and, if necessary, surfaced. All the work is carried out on the site. CF: plant mix mixite a. A hexagonal mineral, BiCu6 (AsO4 )3 (OH)6 .3H2 O . CF: chlorotile b. The mineral group agardite, goudeyite, mixite, and petersite. mix-metal Cerium alloy (55% to 65%) containing rare-earth metals and iron. Bennett mixture A commingling in which the ingredients retain their individual properties or separate chemical nature. See also: mechanical mixture Standard, 2 mizzonite One of the series of minerals forming the scapolite groups, consisting of a mixture of the meionite and mariolite molecules. It includes those minerals with 54% to 57% silica, and occurs in clear crystals in the ejected masses on Mount Somma, Vesuvius, Italy. Also called dipyrite. See also: dipyre MM diamond Synthetic manufactured diamond. Long moat a. A ditch or deep trench. b. To surround with a ditch. 2032

moating A backing of clay, as for the masonry lining of a shaft. Standard, 2 mobile belt An elongated zone of the Earth's crust subjected to relatively great structural deformation. CF: geosyncline mobile conveyor A hand-loaded, hoist-operated hauler used principally in certain central Pennsylvania coal mines. It is essentially a chain-and-flight conveyor of exceptional width, with high sideboards, mounted on wheels for operation on mine track, with motive power supplied by a hoist mounted on the chassis of the machine. The conveyor chain and flights can be moved in the bed of the machine to assist in loading or unloading. The hoist rope can be attached to props at the face and near the dumping point to provide anchorage when the conveyor is moved. Jones, 1 mobile crane A crane driven by gasoline, diesel, or electric motor, traveling on crawler tracks, pneumatic tires or solid rubber tires, and capable of moving in any direction under its own power. Hammond mobile drill A drill unit mounted on wheels or crawl-type tracks to facilitate moving. Long mobile equipment Applied to all equipment that is self-propelled or that can be towed on its own wheels, tracks, or skids.See also: transportable equipment Nelson mobile hoist A platform hoist which is mounted on a pair of pneumatic-tired road wheels, so that it can be towed from one site to another. This type of hoist has been developed for use in house and flat construction. See also: platform hoist mobile loader A self-propelling machine capable of lifting material off the bottom and placing it in a mine car, conveyor, or other means of transportation. Jones, 1 2033

Mocha stone Syn: moss agate mock lead A Cornish term for zinc blende; also called wild lead. See: sphalerite Fay mock ore See: sphalerite mock vermilion A basic chromate of lead. mode a. The mineral composition of a rock, usually expressed in weight or volume percentages. Adj: modal. CF: norm b. The value or group of values that occurs with the greatest frequency in a set of data; the most typical observation. CF: mean model a. A facsimile in three dimensions--a reproduction in miniature of the surface and underground workings of a mine, showing the shafts, tunnels, crosscuts, etc., in all their details. From its very nature, it does not fall within any definition of the word map and it is a misapplication of the term to call it a map, though it may far better serve the purpose in hand. Ricketts b. A unifying concept that explains or describes a complex phenomenon. See also: mineral deposit model model analysis The comprehensive testing of scale models of various structures, including harbors and rivers to determine the behavior of the actual structure under consideration. See also: photoelasticity modeler a. Person who shapes plaster of Paris, clay, etc., to form original models used to make molds for producing ceramic ware. b. Person who builds models used in model analysis. modeling clay

2034

Fine, plastic clay, esp. prepared for artists in modeling by kneading with glycerin, or by other methods. Fay moderate vitrain A field term that, in accordance with an arbitrary scale established for use in describing banded coal, denotes a frequency of occurrence of vitrain bands comprising from 13% to 30% of the total coal layer. CF: sparse vitrain; abundant vitrain; dominant vitrain. AGI modified longwall A method used in room-and-pillar mining where the lease requires at least 80% of recovery. Basically it consists of turning the rooms on 70-ft (21.3-m) centers then working the room up 30 ft (9.1 m) wide and butting it off at its completion, then withdrawing the remaining 40 ft (12.2 m) of pillar immediately. Kentucky modified room-and-pillar working See: bord-and-pillar method modified-round nose See: medium-round nose modifier In froth flotation, reagent used to control alkalinity and to eliminate harmful effects of colloidal material and soluble salts. See also: modifying agent modifying agent In flotation, a chemical that increases the specific attraction between collector agents and particle surfaces, or conversely, that increases the wettability of those surfaces. Pryor, 3 modulating A control adjusting by increments. Strock, 2 modulus of elasticity The ratio of stress to its corresponding strain under given conditions of load, for materials that deform elastically, according to Hooke's law. It is one of the elastic constants. See also: modulus of rigidity; bulk modulus. Syn: elastic modulus; longitudinal velocity. AGI 2035

modulus of incompressibility The ratio between the pressure in the mass of a soil and the change of volume caused by such pressure. CF: Poisson's ratio modulus of rigidity a. The rate of change of unit shear stress with respect to unit shear strain, for the condition of pure shear within the proportional limit. For nonisotropic materials such as wood it is necessary to distinguish between the moduli of rigidity in different directions. Roark b. A modulus of elasticity in shear. Symbol: mu or G. Syn: shear modulus; rigidity modulus; coefficient of rigidity. AGI modulus of rupture a. Nominal stress at fracture in a bend test or a torsion test. In bending, modulus of rupture is the bending moment at fracture divided by the section modulus. In torsion, modulus of rupture is the torque at fracture divided by the polar-section modulus. ASM, 1 b. The load required to break a piece of material, such as a refractory brick, supported on two spaced and parallel flat bearing edges with the load applied through a third bearing edge placed midspan and on top of the piece. ARI Moebius process A method of electrolytic refining of silver. Silver plate of 95% to 98% pure forms the anodes, and thin silver plate forms the cathodes. The electrolyte consists of a weak, acidulated solution of silver nitrate. Fay Moe gage A diamond-weight calculator which estimates to within a few hundredths the weights of brilliant-cut diamonds only, by simple measurements of width and depth of both set or unset diamonds. Hess mofette The exhalation of carbon dioxide in an area of late-stage volcanic activity; also, the small opening from which the gas is emitted. Occurs in Yellowstone National Park. Etymol: French, noxious gas. AGI moganite Monoclinic silica, SiO2 (silica-G), with quartz in chert from dry lake beds; also cavity fillings in rhyolitic ignimbrites. Named for Mogan, Canary Islands. 2036

mogensenite Titaniferous magnetite with exsolved ulvoespinel. CF: titanomagnetite mohavite A dull white hydrous borate of sodium, Na2 B4 O7 .5H2 O . Rhombohedral. An alteration film on borax. Locally, octahedral borax (same as tincalconite). From the Mohave Desert, CA. See also: octahedral borax Moho Short name for the Mohorovicic discontinuity separating the Earth's crust from the mantle. Mather mohole The never-completed program to drill through the Earth's crust under the ocean to the Mohorovicic discontinuity in order to provide scientific knowledge of the Earth's mantle. Hy Mohorovicic discontinuity The boundary surface or sharp seismic-velocity discontinuity that separates the Earth's crust from the subjacent mantle. It marks the level in the Earth at which P-wave velocities change abruptly from 6.7 to 7.2 km/s (in the lower crust) to 7.6 to 8.6 km/s or average 8.1 km/s (at the top of the upper mantle); its depth ranges from about 5 km beneath the ocean floor to about 35 km below the continents, although it may reach 60 km or more under some mountain ranges. The discontinuity probably represents a chemical change from basaltic or simatic materials above to peridotitic or dunitic materials below, rather than a phase change (basalt to eclogite); however, the discontinuity should be defined by seismic velocities alone. It is variously estimated to be between 0.2 and 3 km thick. It is named in honor of its discoverer, Andrija Mohorovicic (1857-1936), Croatian seismologist. Abbrev. Moho. Syn: M-discontinuity AGI Mohr balance See: Westphal balance Mohr circle A graphical representation of the stresses acting on the various planes at a given point. ASCE 2037

Mohr-Coulomb criterion The most popular of numerous rock failure criteria. It assumes that there is a functional relationship between the normal and shear stresses acting on a potential failure surface. SME, 1 Mohr envelope The envelope of a series of Mohr circles representing stress conditions at failure for a given material. According to Mohr's rupture hypotheses, a rupture envelope is the locus of points, the coordinates of which represent the combination of normal and shearing stresses that will cause a given material to fail. Syn: rupture envelope; rupture line. ASCE Mohr's salt A ferrous-ammonium sulfate, FeSO4 (NH4 )2 SO4 .6H2 O ; a light green crystalline salt. Mohr's theory Mohr's theory of failure utilizes the well-known stress circle and the envelope of a family of circles as criteria for failure of materials subject to biaxial or triaxial stress. Thus Mohr's theory predicts that failure of materials is due to failure in shear, whereas Griffith's theory postulates that it is due to failure at crack tips. Lewis mohsite A plumboan variety of crichtonite. Mohs scale Arbitrary quantitative units by means of which the scratch hardness of a mineral is determined. The nonlinear units of hardness are expressed in numbers ranging from 1 through 10, each of which is represented by a mineral that can be made to scratch any other mineral having a lower-ranking number; hence the minerals are ranked from the softest, as follows: talc (1) ranging upward in hardness through gypsum (2), calcite (3), fluorite (4), apatite (5), orthoclase (6), quartz (7), topaz (8), corundum (9), to the hardest, diamond. CF: hardness; Knoop hardness. Long moil point A solid bar of casehardened steel, pointed at one end, with a shank and upset collar at the other. The moil point, hammered into rock or concrete, produces a small hole that gradually deepens and widens until the sides of the point are in full contact with the rock. The effect is then that of wedging, similar to plug-and-feathering. Carson, 1 2038

moissanite A hexagonal mineral, alpha-SiC (Carborundum); in meteorites. See also: Carborundum Moissan process A process for the reduction of chromic oxide with carbon in an electric furnace, the hearth of which is lined with a calcium chromite prepared by heating together lime and chromic oxide. Fay moisture a. Agreed percentage of water content to be allowed in mineral products that are sold. b. Essentially water, quantitatively determined by definite prescribed methods which may vary according to the nature of the material. moisture allowance A deduction from the inital weight of washed coal to allow for the expected loss of water by drainage. BS, 4 moisture content The percentage moisture content equals the weight of moisture divided by the weight of dry soil multiplied by 100. The moisture content of a coal or mineral sample consists of two portions, namely, the free or surface moisture which can be removed by exposure to air, and the inherent moisture which is entrapped in the fuel, and is removed by heating at 200 degrees F (93.3 degrees C). Syn: inherent moisture; water content. Nelson moisture-density curve See: compaction curve moisture-density test See: compaction test moisture equivalent The ratio of the weight of water--which soil, after saturation, will retain against a centrifugal force 1,000 times the force of gravity--to the weight of the soil when dry. The ratio is stated as a percentage. AGI moisture-holding capacity 2039

The quantity of moisture (not removable by mechanical means) contained by a coal in equilibrium with an atmosphere saturated with water vapor. This is employed in some systems of classification as a criterion of rank. BS, 4 moisture man Person who determines the moisture content of ores or concentrates by removing a sample from pile or conveyor, using a metal paddle, and weighing the sample before and after drying. DOT moisture meter An instrument for determining the percentage of moisture in a substance such as timber or soil, usually by measuring its electrical resistivity. See also: atomic moisture meter moisture sample A sample taken for the determination of moisture content. Newton, 1 mojavite See: tincalconite molasse a. A partly marine, partly continental sedimentary facies consisting of a thick sequence of fossiliferous conglomerates, sandstones, shales, and marls, characterized by primary sedimentary structures and sometimes by coal and carbonate deposits. It is more clastic and less rhythmic than the preceding flysch facies. AGI b. An extensive sedimentary formation representing the totality of the molasse facies resulting from the wearing down of elevated mountain ranges during and immediately after the main paroxysmal (diastrophic) phase of an orogeny, and deposited considerably in front of the preceding flysch. Adj: molassic. CF: flysch molasses/AN explosive An explosive mixture consisting of about 80 lb (36.5 kg) of ammonium nitrate mixed with 10 pints (4.7 L) of molasses and 5 pints (2.37 L) of water, for quarry and opencast blasting. The molasses and water may be used instead of fuel oil and give a denser mixture with improved fragmentation. Nelson mold A body of molding sand or other heat-resisting material containing a cavity which when filled with molten metal yields a casting of the desired shape. See also: die 2040

moldavite a. A tektite from the Moldau valley, Czech Republic. Syn: glass meteorite b. A variety of ozocerite from Moldavia. See also: bouteillenstein moldboard a. A board on which to ram a pattern. Standard, 2 b. A curved surface of a plow, dozer, or grader blade, or other dirt mover, which gives dirt moving over it a rotary, spiral, or twisting movement. Nichols, 2 molded cameo A cameo produced by casting in a mold material such as ceramics, metals, glass, plastics, or sealing wax. CF: pressed cameo moldering An obsolete term for decomposition of organic matter under conditions of insufficient oxygen. AGI molders' rule A ruler, with measurements sufficiently elongated to compensate for the heat expansion and contraction of a metal. Such rules are used in metal casting to correct dimensions to normal temperatures. Bennett molding a. The practice of pouring molten metal into suitable molds. Hansen b. The pressing of powder to form a compact. ASTM molding compound A mixture of resins, ingredients, and fillers before processing into the finished product. Jessop molding frame A template to shape a loam mold. Standard, 2 molding hole An excavation in a foundry floor for large castings. Standard, 2 2041

moldings Derb. Weathered ore at the surface of an outcrop. Arkell mold plug A truncated-cone-shaped refractory piece which sits in the bottom of an ingot mold. AISI mole a. A massive, solid-fill nearshore structure of earth, masonry, or large stone that may serve as either a breakwater or a pier. Hy b. An egg-shaped device pulled behind the tooth of a subsoil plow to open drainage passages. Also called mole ball. Nichols, 1 c. Weight in grams of a compound in terms of its molecular weight. Pryor, 3 molecular crystal Loosely bound aggregate of stable molecules; e.g., dry ice, solid iodine, sulfur, paraffin, and most of the other crystalline organic solids. Newton, 1 molecular filter sampler Using a porous membrane filter of very small openings, this sampler achieves nearly 100% efficiency at moderate rates of flow. Membranes of three different porosities are used to permit the sampling of dusts of varying concentrations and particle sizes. Flow rate is controlled by the use of calibrated orifices. Syn: membrane filter molecular sieve A microporous structure of either crystalline aluminosilicates, such as zeolites, or crystalline aluminophosphates, created by dehydration so that the empty cavities in the structure where water molecules were previously present will accept any material that can penetrate the cavity. The sieving action is a function of the pore size of the structure. molecule a. The smallest part of a substance that can exist separately and still retain its composition and characteristic properties. b. The smallest combination of atoms that will form a given chemical compound. mole mining A method of working coal seams about 30 in (76.2 cm) thick, using a small continuous miner type of machine, which is remotely controlled from the roadway and without any associated supports. The machine is used to cut and extract sections of coal about 6 ft 2042

(1.8 m) wide for a distance of 100 yd (91 m) or so from pillars alongside the roadway. Small ribs of coal, 3 to 6 ft (approx. 1 to 2 m) wide, are left between the sections extracted by the machine. The accurate steering of the machine is a critical feature of this system of mining. See also: coal auger molengraafite See: lamprophyllite moler A deposit of diatomite of marine origin occurring on the island of Mors, Denmark. It has been worked since 1912 for use as a heat insulating material, as a constituent of special cements, and for other purposes. Dodd molten slag A waste product of smelting; usually a mixture of silicates. Kirk moluranite An amorphous mineral, H4 U(UO2 )3 (MoO4 )7 .18H2 O . molybdenite A hexagonal and trigonal mineral, MoS2 ; polymorphous with jordisite; foliated; soft; metallic lead gray; an accessory in granites and deep veins; an ore of molybdenum. molybdenum A silvery-white, very hard, metallic element. Symbol, Mo. Does not occur native, but is obtained principally from molybdenite. Wulfenite (PbMoO4 ), and powellite (Ca(MoW)O4 ) are also minor commercial ores. Valuable as an alloying agent with steel and nickel. Used for electrodes in electrically heated glass furnaces, in nuclear energy applications, and for missile and aircraft parts. Handbook of Chemistry and Physics, 3 molybdenum aluminide Mo3 Al; melting point, 2,150 degrees C. Although its oxidation resistance is poor compared to other aluminides and silicides, it is good compared to molybdenum metal. It is a refractory crucible material for melting certain metals. Lee molybdenum anhydride See: molybdenum trioxide 2043

molybdenum borides Five compounds have been reported: Mo2 B , melting point, 2,120 degrees C, and sp gr, 9.3; Mo3 B2 , dissociates at 2,250 degrees C; MoB, exists in two crystalline forms: alpha MoB, melting point, 2,350 degrees C, sp gr, 8.8; and beta MoB, melting point, 2,180 degrees C, sp gr, 8.4; Mo2 B5 , dissociates at approx. 1,600 degrees C, sp gr, 7.5; and MoB2 , melting point, 2,100 degrees C, sp gr, 7.8, and thermal expansion, 7.7 x 10-6 . Dodd molybdenum carbides MoC, melting point 2,692 degrees C, sp gr, 8.5; Mo2 C , melting point 2,687 degrees C, sp gr, 8.9. Dodd molybdenum disilicide MoSi2 ; gray; metallic; tetragonal; and melting point, 2,000 degrees C. It has good oxidation resistance at elevated temperatures; maintains fairly good strength; and has refractory applications. Molecular weight, 152.11; sp gr, 6.31 (at 20.5 degrees C); insoluble in acids and in aqua regia; and soluble in hydrofluoric acid plus nitric acid. Syn: molybdenum silicide molybdenum mineral Most molybdenum is a byproduct of mining porphyry copper deposits. molybdenum silicide See: molybdenum disilicide molybdenum trioxide MoO3 ; white at ordinary temperatures; yellow at elevated temperatures; molecular weight, 143.94; orthorhombic; sp gr, 4.69 (at 21 degrees C); melting point, 795 degrees C; boiling point, 1,264 degrees C or sublimes at 1,155 degrees C, at 1 atmophere (101 kPa); sparingly soluble in water; very soluble in excess alkali with the formation of molybdates; and soluble in concentrated mixtures of nitric and hydrochloric acids and in mixtures of nitric and sulfuric acids. CCD, 2; Handbook of Chemistry and Physics, 2 molybdic ocher See: ferrimolybdite molybdic oxide 2044

See: molybdenum trioxide molybdite See: ferrimolybdite; molybdenum trioxide. molybdomenite A monoclinic mineral, PbSeO3 . molybdophyllite A trigonal mineral, Pb2 Mg2 Si2 O7 (OH)2 . moment distribution A method of calculating bending moments, in redundant frames and continuous beams, using successive approximations. Hammond moment of force The turning effect on a body about a point called a pivot or fulcrum. In practice, the turning effect is commonly called leverage. Syn: turning effect moment of inertia Resistance by a body to angular acceleration about a specific axis of rotation. Pryor, 3 moment of resistance The couple produced by the internal forces in a beam subjected to bending under the maximum permissible stress. Hammond momentum Mass times velocity. Pryor, 3 momentum grade Grade so situated that the kinetic energy of a train (due to its speed at the foot of the grade) will enable the locomotive to haul the train to the top without a reduction of speed below 10 or 12 mph (16.1 to 19.3 km/h). Urquhart Momertz-Lintz system 2045

A unique winding arrangement where two winding engines are arranged alongside the shaft, the shaft collar forming a common foundation. The ropes are practically vertical and there is less rope oscillation. Sinclair, 5 M.O. Mine safety indicator A system showing, by means of lights, the position of all switchgear underground, with a master control that would show up if a section of a mine had been switched off at the substation, leaving switches going into the mine in the on position. A recorder gives a complete operating picture of a power-loading face. Nelson monad An axial rotation of 360 degrees , one-fold. See also: axis of symmetry monadnock A residual hill rising above a peneplain, representing an isolated remnant of a former erosion surface. It is named after Mt. Monadnock, NH. CF: inselberg monazite a. A monoclinic mineral, (Ce,La,Y,Th)PO4 ; waxy yellow to brown; an accessory in granites; pegmatites, and placers; a source of thorium and rare earths; further speciated according to the dominant rare-earth element. See also: zircon group b. The mineral group brabandite, cheralite, huttonite, monazite, and rooseveltite. monazite sand See: monazite moncheite A trigonal mineral, (Te,Bi)2 ; melonite group; steel-gray; in chalcopyrite on the Kola Peninsula, Russia. monchiquite A lamprophyre containing phenocrysts of olivine, clinopyroxene, and typically biotite or amphibole (barkevikite), in a groundmass of glass or analcime, often highly altered. Nepheline or leucite may be present. Its name is derived from Serra de Monchique, Portugal. AGI Mond process 2046

A process for extracting and purifying nickel. The main features consist of forming nickel carbonyl by reaction of the finely divided reduced metal with carbon monoxide, and decomposing the nickel carbonyl, with deposition of nickel on small nickel pellets. ASM, 1 monetite A triclinic mineral, CaHPO4 ; yellowish-white; in phosphorites. mongrel Eng. Irregular gray limestone, Lower Lias, Lyme Regis. Arkell monheimite A variety of smithsonite containing iron carbonate. Fay monitor a. A high-pressure nozzle, mounted in a swivel on a skid frame, used to direct highpressure water (hydraulic water) on unconsolidated gravels and sands in alluvial mining to break down, wash, and transport them. Syn: hydraulic monitor b. A self-dumping car, holding from 5 to 8 tons of coal. It is filled by emptying the mine car into it at the foot of the slope or top of the incline. See also: gunboat c. A gas sampler for continuous sampling of the atmosphere in a mine, usually sounding an alarm when the gas threshold is exceeded. Hartman, 1 d. An instrument that measures ambient conditions in an area. Lyman e. In hydraulicking, a high-pressure nozzle mounted in a swivel on a skid frame. Nichols, 2 monitor operator See: incline man monkey a. The word monkey prefixed to a technical term means small, thus: monkey chute, a small chute; monkey drift, a small drift, usually driven in for prospecting purposes. Fay b. An appliance for mechanically gripping or letting go the rope in rope haulage. Fay c. A block placed between the rails on an incline to prevent cars from running back. Syn: monkey chock; bobbin. Standard, 2 monkey board A single, unrailed, heavy plank, mounted above the drill platform in the derrick or tripod and serving as a walkway or work platform. Long 2047

monkey chock Aust. See: monkey; bobbin. monkey drift A small drift driven in for prospecting purposes, or a cross-cut driven to an airway above the gangway. Zern monkey face A term applied to a chain bracket to be inserted between adjacent shaker conveyor troughs to permit suspension of the trough line from the roof. Jones, 1 monkey gangway a. Pennsylvania. An air course driven parallel with a gangway and heading at a higher level. Used where a seam has considerable pitch or dip. Fay b. A small gangway parallel to a main gangway. Hudson monkey hair Caotchouc, or rubber, derived from a milk juice of plants and which fills latex cells and tubes. It is resistant to decomposition and found in many brown coals as a wooly mass. Stutzer monkey heading A narrow and low passage driven in the coal where miners take refuge while coal is being blasted. Chiefly in mines where seams pitch sharply. Korson monkey hole See: doghole monkey roll Any of the smaller rolls in an anthracite breaker. monkey shaft A small shaft raise extending from a lower to a higher level. Fay monkey winch 2048

A device for exerting a strong pull; may be used to withdraw steel arches from disused roadways. It consists of a framework containing a hand-operated drum, around which a steel rope 50 ft (15.24 m) in length is wound. To hold the drum in position a ratchet device is used with both gears. A simple reversing mechanism that disengages the ratchet is also attached. The winch is firmly anchored when in use. See also: winch; sylvester. Nelson monkey wrench An adjustable wrench named for its inventor, Thomas Monkey. Crispin Monnier process The treatment of copper sulfide ores by roasting with sodium sulfate, and subsequent lixiviation and precipitation. Fay monobasic Containing one hydrogen atom replaceable by a metal with the formation of a salt. CTD monocable A form of aerial ropeway in which the same rope is used both to support and haul along the overturning skips in which the debris is carried. These rest upon the rope and obtain a sufficient frictional grip on it to be carried up moderate gradients and over pulleys by means of an inverted Vee-shaped saddle lined with wood, rubber, or composition. The rope is driven by a surge wheel in a similar manner to an endless-rope haulage. See also: aerial ropeway; fixed-clip monocable. Sinclair, 5 monochromatic Having or consisting only of one color or frequency. monochromatic light Electromagnetic radiation of a single wavelength or frequency. monoclinal Adj. of monocline. monocline A local steepening in an otherwise uniform gentle dip. CF: anticlinal bend; homocline; flexure. Adj: monoclinal. Obsolete syn: unicline. AGI 2049

monoclinic block A quarryman's term for blocks with two parallel sets of sides at right angles and one parallel set not at right angles. monoclinic system All point groups characterized by lattices with two crystallographic axes at right angles and one axis inclined. See also: crystal systems monogene a. See: monogenetic b. Said of an igneous rock (such as dunite) composed essentially of a single mineral. Syn: monomineralic monogenetic a. Resulting from one process of formation or derived from one source, or originating or developing at one place and time; e.g., said of a volcano built up by a single eruption. AGI b. Consisting of one element or type of material, or having a homogeneous composition; e.g., said of a gravel composed of a single type of rock. CF: polygenetic monograin A free-flowing high explosive widely used for charging bulled holes and large-diameter (well drill) holes. Nelson monolith a. A piece of unfractured bedrock, generally more than a few meters across; e.g., an unweathered joint block moved by a glacier. AGI b. A large upstanding mass of rock, such as a volcanic spine. AGI c. One of many large blocks of stone or concrete forming the component parts of an engineering structure, such as a dam. AGI d. A vertical soil section, taken to illustrate the soil profile. AGI monolithic refractory Furnace lining made in one piece or formed by casting, ramming, or tamping into position. Osborne monomaceral Coal microlithotype consisting of a single maceral; i.e., fusite or vitrite. AGI monomineralic 2050

See: monogene Monongahelan Upper Pennsylvanian geologic time. AGI Monongahela series The Upper Productive Coal Measures of the Pennsylvanian, of which they constitute the highest member. CTD Mono pump This pump consists essentially of a rubber stator in the form of a double internal helix and a single helical rotor which rolls in the stator with a slightly eccentric motion. The rotor maintains a constant seal across the stator and this seal travels continuously through the pump, giving a positive uniform displacement. The Mono pump is manufactured to meet mining conditions. The rotor is made of special abrasion-resisting or noncorroding steel. The length of the stator and rotor provides for a twist of slightly more than 360 degrees to provide for a complete seal. For greater heads the length of stator and rotor are increased so as to provide two or more complete seals in series and the head is then developed in stages. Syn: progressing cavity pump monopyroxene See: clinopyroxene monorail A relatively new underground transport system in which the carriages, or buckets, are suspended from, and run along, a single continuous overhead rail or taut wire rope. The monorail is used in coal mines to transport supplies to the workings. It may be installed alongside the gate conveyor and worked by endless or main rope. See also: overhead monorail; overhead-rope monorail; Becorit system. Nelson monorail crane A traveling crane suspended from a single rail. Crispin monoschematic Said of a body of rock or a mineral deposit, the fabric of which is identical throughout. monotower crane 2051

A tower crane that rotates through a full circle and is erected on a fixed base. Hammond monotron An indentation hardness testing machine by which measurements are obtained by the pressure required to indent a specimen with a diamond 5/8 mm in diameter, the depth of indentation remaining constant. Henderson monotron hardness test A method of determining the indentation hardness of metals by measuring the load required to force a spherical penetrator into the metal to a specified depth. ASM, 1 monovalent a. Having a valence of 1. Webster 3rd b. Having one valence; e.g., calcium, which has only one valence of 2. Webster 2nd montana a. Sp. Mountain. b. Mex. Ores scattered through country rock and not found in deposits of any appreciable size. Montana agate Moss agate from Montana. Montana ruby Red garnet, pyrope or almandine. Montana sapphire Electric or steel-blue sapphire from Montana. montanite A possibly monoclinic mineral, Be2 TeO6 .2H2 O ; yellow to white; forms earthy encrustations. montan wax A solid bitumen that may be extracted by solvents from certain lignites or brown coals. It is white to brown and melts at 77 to 93 degrees C. AGI 2052

montasite A variety of amosite; an asbestiform variety of amphibole. Mont Blanc ruby Rose quartz from Mont Blanc, southeastern France. montbrayite A triclinic mineral, (Au,Sb)2 Te3 ; forms tin-white crystals at Montbray, Quebec. Named for the locality. montebrasite A triclinic mineral, LiAl(PO4 )(OH1 F) ; amblygonite group; perfect cleavage; occurs in granite pegmatites where it may be a source of lithium. Montgomery jig A plunger-type jig with the plunger beneath the screen. The distinguishing feature of this jig is the use of two sets of valves beneath the screen plate. Used in washing bituminous coal, both closely sized and slack sizes. Mitchell Montian European stage: Paleocene (above Danian, below Thanetian). AGI monticellite An orthorhombic mineral, MgCaSiO4 ; olivine group; in contact-metamorphosed limestones, rarely in ultramafic rocks. CF: glaucochroite monticule A small hill, knob, or mound; esp., a minor volcanic cone. montiform Mountainlike; having the shape of a mountain. montmorillonite A monoclinic mineral, (Na,Ca)0.33 (Al,Mg)2 Si4 O10 (OH)2 .nH2 O ; smectite group; expansive and cation exchangeable; perfect basal cleavage; in bentonite clays formed by 2053

alteration of volcanic ash or mafic igneous rocks. The chief constituent of bentonite and fuller's earth. CF: beidellite; hectorite. Syn: amargosite montre An opening in a kiln wall to permit inspection of the contents. Standard, 2 montroseite An orthorhombic mineral, (V,Fe)O(OH) ; black; a primary mineral in sandstone-type uranium-vanadium ores associated with roscoelite, pitchblende, coffinite, and secondary uranium and vanadium minerals. montroydite An orthorhombic mnineral, HgO ; sectile; perfect cleavage; sp gr, 11.2; a rare secondary mineral; in the oxidized zone of some mercury deposits. monument a. The structure erected to mark the position of a corner. Permanence is implied. In a legal sense, a monument is any physical evidence of a boundary of real property. Seelye, 2 b. Survey point; e.g., a pile of stones indicating the boundary of a mining claim. AGI monzonite A granular plutonic rock containing approx. equal amounts of orthoclase and plagioclase, and thus intermediate between syenite and diorite. Quartz is minor or absent. Either hornblende or diopside, or both, are present and biotite is a common constituent. Accessories are apatite, zircon, sphene, and opaque oxides. The intrusive equivalent of latite. Syn: syenodiorite mooihoekite A tetragonal mineral, Cu9 Fe9 S16 ; in magmatic sulfide deposits; a significant copper ore mineral at Noril'sk, Russia. moonstone a. A semitransparent to translucent variety of alkali feldspar (adularia) or cryptoperthite that exhibits a bluish to milky-white pearly or opaline luster; an opalescent variety of orthoclase; a gemstone if flawless. CF: sunstone b. A name incorrectly applied to peristerite or to opalescent varieties of plagioclase (esp. albite). c. A name incorrectly applied (without proper prefix) to milky or girasol varieties of chalcedony, scapolite, corundum, and other minerals. 2054

moonstone glass A type of opal glass resembling the mineral moonstone. ASTM moor a. A more or less elevated tract of barren land, having, as a rule, a rather broad, flat, and poorly drained surface, commonly diversified by peat bogs and patches of heath. b. A common term for peat unfit for use, as opposed to turf, which is dug for fuel. Tomkeieff moorband See: moorband pan moorband pan Eng. A hard ferruginous crust that forms at the bottom of boggy places above a stiff and impervious subsoil. Moore and Neill sampler A sediment coring device containing a protected glass tube through which water flows freely during descent and which is forced by impact into the sediment. On hauling, a simple valve mechanism closes the top of the tube and the sample may be brought to the surface. The body of the sampler is a brass cylinder into which fits a thinner metal tube holding the glass sampling tube. When the glass tube is in position, it is closed by a rubber bung that comes hard against the upper surface of the main body of the sampler in the center of which is a hole. Hunt Moore filter press A movable, intermittent vacuum filter consisting of a series, or basket, of leaves fastened together in such a way that it may be dropped in a pulp tank and kept submerged until a cake is formed; it is then transferred by crane to an adjoining wash-solution tank and washed; the basket is then lifted out of the tank and the cake dropped. Liddell Moore free corer A sediment sampler designed to drop free from a ship to the sea floor, obtain a core, and return to the surface, leaving its expendable weight and casing embedded in the bottom. The free corer consists of two basic assemblies: (1) a recoverable core barrel, check valve, buoyant chamber assembly filled with gasoline; and (2) an expendable weight and casing assembly. When these two assemblies are combined, the core barrel fits loosely inside the casing. The device is dropped over the side of the ship and allowed to fall free 2055

to the bottom. A simple release-delay timer made of magnesium releases the core barrel and its buoyant float rises from the weight and casing assembly. Hunt moorland peat See: highmoor peat moorlog a. Remains of a submerged forest, composed of a tangled mass of brushwood and tree trunks and forming a layer from 3 to 8 ft (0.9 to 2.4 m) thick. Tomkeieff b. Hard, brown peat dredged by fishing boats from the bed of the North Sea. Arkell moor peat See: highmoor peat moose pasture Can. Derisive term applied to mining country that is largely muskeg. Hoffman mor In contrast to "mull", a type of forest soil in which the humus layer forms a dense carpet over the soil. Synonymous with raw humus. Tomkeieff; AGI morainal apron See: apron moraine A mound, ridge, or other distinct accumulation of unsorted, unstratified glacial drift, predominantly till, deposited chiefly by direct action of glacier ice, in a variety of topographic landforms that are independent of control by the surface on which the drift lies. See also: boulder clay; till. AGI Moran and Proctor sampler A simple, split-tube, drive-type soil-sampling barrel. The sampler is equipped with a thin-walled unsplit brass liner, which can be capped and sealed to act as a watertight shipping container for the sample. Long morass ore 2056

See: bog iron; bog iron ore. Morcol A semigelatinous permitted explosive possessing both high power and good waterresisting properties. It has a density about midway between Dynobel No. 2 and Ajax. Nelson mordant A substance used in dyeing to fix the coloring matter, as a metallic compound that combines with a organic dye to form an insoluble colored compound, or lake, in the fiber of a fabric. Webster 3rd mordenite A white, yellowish, or pinkish member of the zeolite group of minerals with the formula (Ca,Na2 K2 )Al2 Si10 O24 .7H2 O . Larsen morenosite An orthorhombic mineral, NiSO4 .7H2 O ; may contain appreciable magnesium; applegreen; in secondary incrustations from the oxidation of nickel-bearing sulfides. Syn: nickel vitriol morganite A rose-colored, alkali-bearing, gem-quality variety of beryl identical with vorobievite. Syn: vorobievite morgen The South African measure of land, equal to 640.25 square rods, 92,196 ft2 (8,565 m2 ), 1.44 claims, or 2.1165 English acres (0.857 ha). There are 284 morgens to a square mile and 735.5 morgens/km2 . Beerman Morisette expansion reamer A reaming device equipped with three tapered lugs or cutters designed so that the drilling pressure necessary to penetrate rock with a noncoring pilot bit forces the diamond-faced cutters of the reamer to expand outward, thereby enlarging the pilot hole sufficiently to allow the casing to follow the reamer as drilling progresses. The casing is rotated with a pipe wrench while the noncoring and expansion bit is turned by the drill, and the casing is allowed to follow down the reamed-out pilot hole about 1-1/2 to 2 in (4 to 5 cm) behind the upper end of the reamer lugs. Long 2057

Morkill's formula Valuation formula used to ascertain present value (Vp) of a mining share. Pryor, 3 morlop A mottled variety of jasper found in New South Wales, Australia; much sought by miners, it commonly occurs with diamonds. morphological crystallography The study of the external shapes of crystals. Hurlbut morphologic unit a. A rock stratigraphic unit identified by its topographic features; e.g., a Pleistocene glacial deposit. b. A surface, either depositional or erosional, recognized by its topographic character. morphology a. The observation of the form of lands. Standard, 2 b. The study of the form and structure of organisms. AGI c. The form or shape of a crystal or mineral aggregate. Adj. morphological. mortar a. The receptacle beneath the stamps in a stamp mill, in which the dies are placed, and into which the rock is fed to be crushed. Fay b. A vessel in which rock is crushed by hand with a pestle for sampling or assaying. Fay mortar bed Lime-cemented, valley-flat deposit of clay, silt, sand, and gravel, found in Nebraska and Kansas; a type of caliche. AGI mortar box The large, deep, cast-iron box into which the stamps fall and the ore is fed in a gold or silver stamp mill; also called stamper box. Fay mortar structure A structure in crystalline rocks characterized by an aggregate of small grains of quartz and feldspar occupying the interstices between, or forming borders on the edges of, 2058

much larger, rounded grains of the same minerals. Long considered a product of cataclasis, the structure may actually be the result of plastic deformation and dynamic recrystallization (Harte, 1977). Syn: porphyroclastic structure See also: cataclastic mortice See: mortise mortification Destruction of active qualities, as in mercury amalgamation. Standard, 2 mortise A rectangular hole cut in one member of a framework to receive a corresponding projection on the mating member. Syn: mortice morts terrains a. Fr. Barren or dead ground. b. The water-bearing strata overlying the Coal Measures. mosaic a. An assembly of aerial or space photographs or images whose edges have been feathered and matched to form a continuous photographic representation of a part of the Earth's surface; e.g., a composite photograph formed by joining together parts of several overlapping vertical photographs of adjoining areas of the Earth's surface. See also: controlled mosaic b. A textural subtype in which individual mineral grains are approx. equal (Harte, 1977). AGI mosaic silver An amalgam of mercury, tin, and bismuth, used for imitating silverwork. Standard, 2 mosaic structure Slight irregularity of orientation of small, angular, and granular regions of varying sizes in a crystal. mosaic texture a. A granoblastic texture in a dynamically metamorphosed rock in which the individual grains meet with straight or only slightly curved, but not interlocking or sutured, boundaries. AGI b. A texture in a crystalline sedimentary rock characterized by more or less regular grain-boundary contacts; e.g., a texture in a dolomite in which the mineral 2059

dolomite forms rhombs of uniform size so that in section contiguous crystals appear to dovetail, or a texture in a orthoquartzite in which secondary quartz is deposited in optical continuity on detrital grains. AGI moschellandsbergite An isometric mineral, Ag2 Hg3 ; a silver-white amalgam; sp gr, 13.5. Named for the locality in Bavaria, Germany. mosesite An isometric mineral, Hg2 N(Cl,SO4 ,MoO4 ,CO3 ).H2 O ; yellow; secondary. See also: kleinite moss a. adj. A fine dendritic growth having the texture of moss; e.g., moss gold. b. A term used for fractures or fissures in gem stones which produce the appearance of moss, such as in many emeralds. moss agate A general term for any translucent chalcedony containing inclusions of any color arranged in dendritic patterns resembling trees, ferns, leaves, moss, and similar vegetation; specif. an agate containing brown, black, or green mosslike markings due to visible inclusions of oxides of manganese and iron. See also: agate; Mocha stone; tree agate. Syn: landscape agate; medfordite. Mossfield loader A scraper-box type of coal loader developed at the Mossfield colliery (Great Britain) in 1953. It consists of a hinged front, scooplike plate which elevates and deflects the broken coal onto an armored conveyor. On inclined faces, the loader is hauled by a double-drum Pikrose haulage. Nelson moss form A material in dendritic forms. mossing During low water in the Salmon River, CA, the algae and other plants growing in the stream are gathered, dried, and burned. The ashes are washed, and some gold is obtained. This process is called mossing. Hess 2060

mossite A tantalum-bearing variety of ferrocolumbite or tapiolite named for the locality in Norway. moss peat Peat derived from water-loving mosses, chiefly sphagnum. See also: highmoor peat mossy zinc Granulated zinc obtained when the molten metal is poured into cold water. mother a. Gouge clay in a mineral vein. Arkell b. Shale adhering to quarried limestone. Arkell c. See: mother crystal mother conveyor A term frequently used in connection with conveyors used in gathering service. The mother conveyor receives coal from other conveyors or gathering machines, such as shuttle cars, and delivers it to some central loading point. See also: underground mine conveyor mother crystal A name given to a mass of raw quartz, either faced or rough, as found in nature. Syn: mother mother gate a. N. of Eng. The main roadway to a coal face up which miners travel; air, power, and supplies pass; and down which coal from the face travels on a conveyor belt. Trist b. Eng. The main road of a district off which crossheadings are set away in longwall working. See also: level; main gate. SMRB Mother Hubbard bit A heavy drag-type or fishtaillike bit having a long grooved shank, the diameter of which is only slightly less than the width of the cutting edges; it is designed for drilling boreholes in formations that mud-up excessively. Long mother liquor 2061

a. The magmatic rest solution from which a mineral deposit has received its metal content. Schieferdecker b. In crystallization, the liquid that remains after the substances readily and regularly crystallizing have been removed. AGI mother lode a. A main mineralized unit that may not be economically valuable in itself but to which workable veins are related; e.g., the Mother Lode of California. CF: master lode b. An ore deposit from which a placer is derived; the mother rock of a placer. AGI mother of coal See: fusain; mineral charcoal. mother-of-emerald See: prase mother-of-pearl Iridescent portion of mollusk shells, made of the mineral aragonite. See also: nacre mother rock A general term for the rock in which a secondary or transported ore deposit originated; mother lode. AGI motion driver In bituminous coal mining, one who operates the engine that moves an endless cable by which cars are raised or lowered along an inclined haulageway. Syn: motioner motioner See: motion driver motion study A technical investigation of the essential movements of a worker when performing a specific task, and assessing the results with the objective of reducing labor and increasing work performance. The study may also include the layout tasks, availability of tools or materials, and the design of new methods. See also: time study motive column 2062

The height of a column of air, of the same density as the air in the downcast shaft, which exerts a pressure equal to the ventilating pressure. It is the ventilating pressure expressed in meters of air column. Also called head. Syn: column; ventilating column. Nelson motive power An agency (such as water, steam, wind, or electricity) used to impart motion to machinery. Webster 3rd motive zone In mine subsidence, that portion of the mined strata which, being still in the process of sinking, goes far to furnish the motive power producing the phenomena. Briggs motometer A speed counter, as for a steam engine; also a speedometer. Crispin motor body The boxlike portion at the lower end of a coal-cutting machine. Fay motor boss In mining, a foreperson who directs locomotive (motor) haulage operations underground and at the surface of a mine. Also called car dispatcher; car distributor; dispatcher; passing boss; traffic man; train dispatcher. Syn: turn keeper motor brakeperson See: locomotive brakeman motor-change man In anthracite and bituminous coal mining, a person who in addition to charging and repairing batteries, removes spent storage batteries from electric mine locomotives and replaces them with freshly charged ones. DOT motor driver In bituminous coal mining, one who operates a small electric haulage locomotive to haul mine cars underground and at the surface of a mine. DOT motor hammer drill 2063

Usually has a built-in gasoline engine as prime mover, flushing being provided by the exhaust gases or by compressed air produced in the machine. Total weight varies between 50 lb and 120 lb (22.7 kg and 54.4 kg). Motor hammer drills are used for oddjob operations, on forest roads, in prospecting, etc., where it is not worthwhile to lay air supply lines on account of transport difficulties or insufficient volume of work. Fraenkel motorized grader See: grader motorman The person who operates a haulage locomotive. Jones, 1 motor nipper See: locomotive brakeman mottle The spotted, blotched, or variegated appearance of any mottled surface, such as of wood or marble; esp., in metallurgy, the appearance of pig iron of a quality between white and gray. Standard, 2 mottled iron Pig iron in which the majority of the carbon is combined with iron in the form of cementite, Fe3 C , but in which there is also a small amount of graphite. The fractured pig has a white crystalline fracture with clusters of dark spots, indicating the presence of graphite. See also: gray iron mottled limestone Limestone with narrow branching fucoidallike, cylindrical masses of dolomite, often with a central tube or hole; a variegated limestone. It may be organic or inorganic in origin. mottled silica brick A silica brick having harmless areas of dark cream to reddish brown. mottled slate

2064

Slate in which blotches of red or purplish colors appear on a generally green surface; ascribed chiefly to different forms of iron oxide. mottled structure Discontinuous lumps, tubes, pods, and pockets of a sediment, randomly enclosed in a matrix of contrasting textures, and usually formed by the filling of animal borings and burrows). AGI mottramite An orthorhombic mineral, PbCu(VO4 )(OH) ; descloizite group; zinc replaces copper toward descloizite; conchoidal fracture; a supergene mineral associated with base-metal deposits. Formerly called cuprodescloizite, psittacinite. mountain brown ore Limonite or brown iron ore. A local name applied in Virginia to the low-grade siliceous variety, which commonly occurs in hard lumps and is found on the mountain slopes at or near the contact of the Cambrian shale and sandstone with the Cambro-Ordovician limestone. CF: valley brown ore mountain building See: orogeny mountain chain A complex, connected series of several more or less parallel mountain ranges and mountain systems grouped together without regard to similarity of form, structure, and origin, but having a general longitudinal arrangement or well-defined trend; e.g., the Mediterranean mountain chain of southern Europe. See also: cordillera AGI mountain cork a. A white or gray variety of asbestos consisting of thick interlaced fibers and resembling cork in texture and lightness (it floats on water). Syn: rock cork; mountain leather. b. A fibrous clay mineral such as sepiolite or palygorskite. mountain flax A fine silky asbestos. mountainite 2065

A monoclinic mineral, (Ca,Na2 ,K2 )2 Si4 O10 .3H2 O ; zeolitelike; white; fibrous. See also: rhodesite mountain leather a. A tough variety of asbestos occurring in thin flexible sheets made of interlaced fibers. Syn: rock leather; mountain cork; mountain paper. b. A fibrous clay mineral such as sepiolite or palygorskite. Syn: leatherstone mountain meal See: diatomite mountain milk A very soft, spongy variety of calcite. Standard, 2 mountain paper A paperlike variety of asbestos occurring in thin sheets; specif. mountain leather or mountain cork. AGI mountain pediment A plain of combined erosion and transportation at the foot of a desert mountain range, similar in form to an alluvial plain but beveling solid rock. mountain railway A railway having such steep gradients that trains are hauled up them by ropes or by a rack locomotive. See also: funicular railway Hammond mountain range A single, large mass consisting of a succession of mountains or narrowly spaced mountain ridges, with or without peaks, closely related in position, direction, formation, and age; a component part of a mountain system or of a mountain chain. AGI mountain soap An unctuous variety of halloysite containing some iron oxide and about 24% water. See also: saponite mountain system 2066

A group of mountain ranges exhibiting certain unifying features, such as similarity in form, structure, and alignment, and presumably originating from the same general causes; esp. a series of ranges belonging to an orogenic belt. CF: mountain chain AGI mountain tar See: mineral tar mountain wood A variety of asbestos that is compact, fibrous, and gray to brown in color, resembling wood. Syn: rockwood mounting In power shovel nomenclature, the mounting consists of a frame on which the entire shovel is supported and on which it moves. Carson, 1 mounting pipe See: column pipe mourite A monoclinic mineral, UMo5 O12 (OH)10 ; forms spherulitic masses of radiating purple fibers in incompletely oxidized uranium ores. mousetrap A cylindrical fishing tool, fitted with an inward-opening flap valve at the bottom end, used to recover small metal fragments from the bottom of a borehole. Long mouth a. The surface outlet of an underground conduit, as of a volcano. AGI b. The collar of a borehole. Long c. An opening resembling or likened to a mouth, such as one affording entrance or exit. Webster 2nd d. The entrance to a mine. BCI e. The top of a mine shaft or the point of entrance to a slant, drift, or adit. Nelson f. The end of a shaft, adit, drift, entry, tunnel, etc., emerging at the surface. Fay g. The opening in a metallurgical furnace through which it is charged; also, the taphole. Fay h. The place of discharge of a stream, as where it enters a larger stream, a lake, or the sea. AGI i. The entrance or opening of a geomorphic feature, such as a cave, valley, or canyon. AGI mouthing 2067

See: shaft inset mouth of pit Aust. The top of a shaft. Fay movable conveyor Any of several types of conveyors designed to be moved in a defined path. See also: portable conveyor; shuttle conveyor. movable jaw The jaw or slip of a safety or foot clamp; it can be raised or lowered into or out of the body or frame of the clamp either to engage or to disengage the drill rods being run into or pulled out of a borehole. Syn: movable slip movable ladder See: man machine movable sieve-type washbox A washbox in which the screen plate supporting the bed of material under treatment is moved up and down in water. BS, 5 movable slip See: movable jaw move-up Extension; move to a forward position. Syn: turnover moving annual total In a study of process costs (in large or in detail) a series of costs-per-unit observed and recorded at regular intervals (usually in monthly financial summaries cross referenced to analyzed detail cost). Twelve months are covered and each month the new month's figures are added and those for the corresponding month of the previous year are removed. Therefore, like periods are always compared and seasonal fluctuations are smoothed out. Abbrev., MAT. Pryor, 3 moving grizzly 2068

Grizzly in which alternate bars rise and then fall gently, any required lateral (conveying) movement being built into the mechanism, therefore reducing loss of headroom in conveying and screening. Other types are traveling bar, ring-roll, and chain grizzlies. Pryor, 3 moya S. Am. Volcanic mud, sometimes carbonaceous. moyle An iron with a sharp steel point, for driving into clefts when levering off rock. Zern M.P.F.M. jet auger An auger equipped with cutting blades; designed so that fluid, under pressure, passing through inclined holes just above the blades, washes away the material loosened by the blades, thereby cleaning the inside of the casing without disturbing the material below the bottom of the casing that is to be sampled. Long MRE The Mining Research Establishment of the National Coal Board, Great Britain. Its prime purpose is to carry out tests and investigations aimed at increasing the efficiency of coal production while maintaining a high level of safety. Nelson MSA distributor A high-air-pressure directional machine which operates in the manner of a whitewashing machine and displaces coal dust from the roof and sides. This machine carries 2 st (1.8 t) of stone dust, and traveling at 11 ft/min (3.4 m/min) distributes over 26 lb/min (11.8 kg/min) of dust. Sinclair, 1 MSA methanometer This methane indicator is one in which the sample is made to flow continuously over the filaments while the determination is being made. In this case, two matched filaments form the adjacent arms of the bridge. One of these is specially activated in order to burn the methane while the other filament is inactive and operates at a somewhat lower temperature. This arrangement is designed to compensate for changes in barometric pressure, temperature, humidity, and the presence of carbon dioxide. Facilities for adjustment are provided to compensate for zero drift and change in battery voltage. The meter is provided with two shunts so that two ranges are provided on the scale: 0% to 5% by 0.1% divisions and 0% to 2% by 0.02% divisions. Roberts, 1 2069

MS connector Nonelectric, short-interval (millisecond, ms) delay device for use in delaying a blast; initiated by detonating cord. mscp Apprev. for mean spherical candlepower. Mason M-series core barrel See: M-design core barrel muck a. Unconsolidated soil, sand, clay, or loam encountered in surface mining; generally, earth which can be moved without blasting. Pryor, 3 b. Useless material produced in mining. Syn: mullock c. A layer of earth, sand or sediment lying immediately above the sand, or gravel containing, or supposed to contain, gold in placer mining districts; it may itself contain some traces of gold. Fay d. Finely blasted rock, particularly from undergound. Nichols, 1 e. To excavate or remove muck from. Webster 2nd muck bar Gray, forge pig iron melted in a puddling furnace, then balled, squeezed, and rolled. Mersereau, 1 muck boss In bituminous coal mining, a person who is in charge of a crew of loaders shoveling rock into cars during the driving of new underground passageways from one part of the mine to another. DOT mucker In mining and quarrying, a laborer who (1) shovels ore or rock into mine cars or onto a conveyor from which mine cars are loaded and at some point are removed from the working face or surfaces of natural stone deposits; or (2) works in a stope shoveling ore into chutes from which it is loaded into cars on haulage level below. Also called car filler; rock passer; shoveler. DOT mucking The operation of loading broken rock by hand or machine, usually in shafts or tunnels. Nelson 2070

muck iron Crude puddled iron ready for squeezing or rolling. Fay muckle Soft clay overlying or underlying coal. muckle hammer A scaling or spalling hammer. Standard, 2 muck saw A saw using an uncharged blade, usually steel, which runs in a bath or stream of carborundum abrasive. Also known as a mud saw. muck shifting Operations concerned with stripping overburden, valuable gravels, or sands in exploitation of opencast mineral deposits. Pryor, 3 muck soil A soil that contains at least 50% organic matter that is well decomposed. AGI mucky hole In a furnace, a taphole from which the iron is so pasty that it does not run freely. Fay mud a. A sticky or slippery mixture of water and silt- or clay-sized earth material, with a consistency ranging from semifluid to soft and plastic; a wet, soft soil or earthy mass; mire, sludge. AGI b. An unconsolidated sediment consisting of clay and/or silt, together with material of other dimensions (such as sand), mixed with water. AGI c. A suspension made by mixing the drill circulation fluid (water) with the fine cuttings produced by the bit when drilling a borehole. Long mud auger A diamond-point bit with the wings of the point twisted in a shallow, augerlike spiral. Also called clay bit; diamond-point bit. See also: mud bit mud balance 2071

An instrument used to measure the density of drill mud. BS, 9 mud barrel a. A double-tube core barrel with a greater-than-normal clearance between the inner and outer tubes, for use with mud-laden circulation liquids. Long b. A bailing device to bring to the surface the cuttings formed by the action of the bit at the bottom of a borehole in free-fall or churn drilling. Long c. A small bailer. Long mud belt The belt of marine deposits composed largely of detrital clay, and lying between the coarser terrigenous sediments to the landward and the deep oceanic organic oozes on the seaward side. At present, the inner boundary of the inner mud belt is the edge of the continental shelf. AGI mud bit A pointed-edge, chisellike tool used for boring drill holes through clay or claylike overburden materials. Also called clay bit; diamond-point bit. See also: mud auger mud blasting In this method, sticks of explosive are stuck on the side of a boulder with a covering of mud, and when detonated, very little of the energy of the explosive is used in breaking the boulder. Higham mud bucket The bucket attached to a dredger. Standard, 2 mud cake The material filling the cracks, crevices, pores, etc., of the rock or adhering to the walls of a borehole. The cake may be derived from the drill cuttings, circulating drill mud, or both; it is formed when the water in the drilling mud filters into porous formations, leaving the mud ingredients as a caked layer adhering to the walls of the borehole. Syn: cake; mud wall cake. Long mudcap A charge of dynamite, or other high explosive, fired in contact with the surface of a rock after being covered with quantity of wet mud, wet earth, or sand, no borehole being used. The slight confinement given the dynamite by the mud or other material permits part of the energy of the dynamite being transmitted to the rock in the form of a blow. A 2072

mudcap may be placed on top or to one side, or even under a rock, if supported, with equal effect. Also called adobe; dobie; sandblast. mudcap method See: secondary blasting mudcapping Method for blasting rock without drilling, in which an explosive is placed on top of the rock and covered by a cap of mud or earth. Syn: adobe charge mud cast See: mud crack mud column The length in feet (meters), as measured from the bottom of a borehole of a drill-mud liquid standing in a borehole either while being circulated during drilling operations or when the drill string is not in the hole. Syn: column of mud mud crack a. The filling of desiccation cracks in mud, customarily in sandstone; generally preserved as raised ridges (casts) arranged in polygonal patterns on the underside of a sandstone bed. Pettijohn, 1 b. An irregular fracture in a crudely polygonal pattern, formed by the shrinkage of clay, silt, or mud, generally in the course of drying. Syn: sun crack; mud cast; shrinkage crack; desiccation crack. AGI mudding Filling voids with clay in limestone from which sulfur has been extracted. Bennett mudding off In petroleum production, commonly thought of as reduced productivity caused by the penetrating, sealing, or plastering effect of a drilling fluid. Actually there is little penetration into the capillaries of an ordinary producing formation, and a slight amount of differential back pressure will remove even thick filter cakes. Brantly, 1 mudflow A general term for a mass-movement landform and a process characterized by a flowing mass of predominantly fine-grained earth material possessing a high degree of fluidity 2073

during movement. The water content of mudflows may range up to 60%. With increasing fluidity, mudflows grade into loaded and clear streams; with a decrease in fluidity, they grade into earthflows. Syn: lahar mud gun An apparatus for pushing a clay stopper into the taphole of a blast furnace. A steam cylinder operates a plunger inside a steel tube into which clay is fed from a hopper tube as the plunger is worked back and forth, and is thus forced into the taphole at the end of a cast. See also: clay gun mud hog a. A pump used to circulate mud-laden drill fluid during borehole drilling operations. See also: mud pump; sludge pump. Long b. Pressure tunnel worker. c. A machine for the disintegration of dry or moist plastic clay. It consists of a rotating swing hammer operating close to a series of anvils linked together to form a steeply inclined slat conveyor. Dodd mud-laden Said of a liquid (usually water) mixed with finely ground earthy or clayey materials. Long mud-laden fluid The water or oil in which mudlike solids are suspended; used to support the open bore and cool and clear the cuttings from a drill bit. The fluid is circulated while rotaryand/or diamond-drilling a borehole. See also: drilling mud mudline Line of demarcation between fairly clear supernatant water and settling solids in a thickener or other sedimentation vessel. Pryor, 3 mud log A continuous analysis of the drilling mud and well cuttings during rotary drilling for entrained oil or gas. Visual observation, ultraviolet fluoroscopy, partition gas chromatograph, and hydrogen-flame ionization analyzer may be used. A drilling-time log is kept concurrently. AGI mud logging

2074

a. A method of determining the presence or absence of oil, gas, and salt water in the various formations penetrated by a drill bit. The drilling fluid and the cuttings are continuously tested on their return to the surface, and the results of these tests are correlated with the depth of origin. Brantly, 1 b. A mud log is a recording vs. depth of the parameters being monitored. Basic parameters monitored are: bit weight, rotary speed, rotary torgue, mud weight, gas content (trip and background) cutting analysis, pit volume, flow rate, pump pressure (strokes), hole depth, and chlorides. This is a common service used to obtain data from the mud system and drilling parameters. mud mixer A machine, pump, hopper, or other apparatus used to mix dry ingredients with water or other liquids to prepare a drill mud. Also called atomizer; jet mixer; mixer. Syn: emulsifier mud pot a. A type of hot spring containing boiling mud, usually sulfurous and often multicolored, as in a paint pot. Mud pots are commonly associated with geysers and other hot springs in volcanic areas, esp. Yellowstone National Park, WY. AGI b. A geyser that throws up mud. Also called mud geyser. Standard, 2; Fay mud pump a. The circulating pump that supplies fluid to a rotary drill. Also called slush pump. See also: mud hog b. See: circulating pump mud ring a. The section of a boiler where scale, alkalies, and sediment collect. b. The ring or frame forming the bottom of a water leg in a steam boiler. Webster 3rd mud rush The more or less sudden inflow of peat, moss, sand, gravel, silt, or any other waterlogged material into shallow mine workings. The manager has a duty to take steps to prevent such inrushes as laid down in the Precautions against Inrushes Regulations, 1956. Also called mud run. See also: inrush of water; running ground. Nelson mud scow A flatboat or barge for the transportation of mud, generally used in connection with dredges. mud snapper 2075

An 11-in-long (28-cm-long), 3-lb (1.4-kg) clamshell-type snapper attached to the bottom of a sounding lead by means of a hole drilled in the lead. The jaws are cast bronze and are actuated by a spring. The jaws are held open by engaging two trigger pins within the jaws. The mud snapper and sounding lead may be operated in shallow water by hand lowering or by lowering from a bathythermograph or oceanographic winch. Hunt mud socket A device attached to drill rods and used to remove sand from a borehole. CF: mule shoe mudstone a. An indurated mud having the texture and composition of shale, but lacking its fissility; a blocky or massive, fine-grained sedimentary rock in which the proportions of clay and silt are approx. equal; a nonfissile mud shale. See also: claystone; siltstone. AGI b. A general term that includes clay, silt, claystone, siltstone, shale, and argillite. AGI mudstone ratio A uranium prospector's term, esp. on the Colorado Plateau, for the ratio of the total thickness of red mudstone to that of green mudstone within an assumed stratigraphic interval. Its value is based upon the premise that uranium-bearing solutions will bleach red mudstone containing ferric iron to green mudstone containing ferrous iron in the course of depositing uranium minerals. AGI mudstone trap A place where uranium mineralization has been trapped at a mudstone-sandstone interface. Ballard mud sump In drilling operations, a mud pit. Long mud up a. The act or process of filling, choking, or clogging the waterways of a bit with consolidated drill cuttings. Also called sludging; sludging up. Long b. The act or process of filling the pores or cracks in the rock surrounding a borehole; also, to cause mud to adhere to the walls of a borehole. Long mud viscosity The property of a mud-laden fluid to resist flow due to internal friction and the combined effects of adhesion and cohesion; e.g., a Marsh funnel (used to measure the viscosity of 2076

mud) will discharge 1 quart (0.95 L) of water in about 36 s, whereas an equal volume of an average drilling mud is discharged in 40 to 55 s or more from the same funneI. Long mud volcano An accumulation, usually conical, of mud and rock ejected by volcanic gases; also, a similar accumulation formed by escaping petroliferous gases. AGI mud wall cake a. See: mud cake b. The formation of mud in the drilling fluid by adhering to the wall of the hole. When the drilling mud particles comes in contact with porous, permeable formation, solid particles immediately enter the openings. This sealing property is dependent upon the amount and physical state of the colloidal material in the mud. muffle a. A semi-cylindrical or long, arched oven (usually small and made of fireclay), heated from outside, in which substances may be exposed at high temperature to an oxidizing atmospheric current, and kept at the same time from contact with the gases from the fuel. Cupellation and scorification assays are performed in muffles; on a larger scale, copper ores were formerly roasted in muffle furnaces. Fay b. An enclosure in a furnace to protect the ware from the flame and products of combustion. ASTM muffle furnace a. A furnace with an externally heated chamber, the walls of which radiantly heat the contents of the chamber. McGraw-Hill, 1 b. A furnace in which heat is applied to the outside of a refractory chamber containing the charge. The charge may be held in a muffle, crucible retort, or other enclosure that is enveloped by the hot flame gases, and the heat must reach the charge by flowing through the walls of the container. CTD; Newton, 1 muffle kiln a. An arched fireclay-lined furnace in which seggars are placed. CTD b. A kiln in which combustion of the fuel takes place within refractory muffles, which, in turn, conduct heat into the ware chamber. ACSG, 2 muffler A muffler that concentrates on suppressing sound waves vibrating 200 to 2,000 times a second--the loudest and most objectionable ones created by rock drills. Because the muffler bypasses the lower frequencies, it does not interfere with the column of air that makes a pneumatic drill function. 2077

mugearite Orthoclase-bearing oligoclase basalt, with major olivine, accessory apatite, and opaque oxides. Pyroxene may or may not be present. See also: trachyandesite mule a. A small car, or truck, used to push cars up a slope or inclined plane. Fay b. See: pusher c. An extra worker who helps push the loaded cars out in case of an upgrade, etc.; from Joplin, Mo. Fay mule's foot Kansas. An extension bit used in boring coal. Hess mule shoe A short length of tubing coupled to the bottom of a drill string to wash and clean out sand or mud from a borehole, the washing action being aided by cutting off the bottom end of the tubing at an angle of 45 degrees to its longitudinal axis. Also called mud socket. Long mule skinner A mule driver. Fay muleway Heavily timbered passage between levels in a mine for the transfer of unattached mules from one level to the other. Korson muller a. Stone, iron shoe, or heavy steel rubbing disk, used to bear down upon rock in comminution. Pryor, 3 b. A heavy grinding wheel that is the crushing and mixing member in a dry or wet pan. ARI c. See: bucking iron mulling Mixing sand and clay particles by a rolling, grinding, rubbing, or stirring action. ASM, 1 mullion structure

2078

A wavelike pattern of parallel grooves and ridges, measuring as much as several feet from crest to crest, and formed on a folded surface or along a fault surface. CF: slickensides mullite An orthorhombic mineral consisting of an aluminum silicate that is resistant to corrosion and heat; used as a refractory. Also known as porcelainite. McGraw-Hill, 1 mullock See: muck multibucket excavator A machine similar to a dredger used for excavating cuttings for roads, railways, or canals. One large machine of this type can dig 100 yd/h (91.4 m/h) on a slope 25 ft (7.62 m) high. Hammond Multicut chain Trade name for a coal-cutter chain designed for use with curved jibs. It is short pitch and of high flexibility. See also: curved jib Nelson multideck cage A cage containing two or more compartments or platforms to hold the mine cars supplies or workers. Every effort is made to keep the number of decks as low as possible for a given output in order to cut down the decking time and equipment at shaft top and bottom. See also: deck Nelson multideck screen A screen with two or more superimposed screening surfaces mounted rigidly within a common frame. BS, 5 multideck sinking platform A sinking platform consisting of several decks to enable various shaft-sinking operations to be performed simultaneously. The bottom deck, in a three-deck platform, is usually suspended from four winch ropes which also act as guides for the kibbles, and the middle and top decks are supported above the bottom deck by rigid supports. The top deck is used for the manipulation of the concrete buckets and for fixing the shuttering. The center deck is used by the workers when placing the concrete, while the bottom deck 2079

carries telephone, blasting, lighting, and signaling cable drums. The lower side of the bottom deck may carry the equipment for manipulating the cactus grab. Nelson multideck table Shaking table with two or more superposed decks, independently fed and discharged but worked by one vibrating mechanism. Pryor, 3 multifuse igniter A device employed to reduce the number of fuses to be lit by the miner before retiring to safety. By means of a multifuse igniter, it is possible to remotely fire stopes or headings primed with plain detonators and safety fuse. Nelson multihearth furnace Roasting furnace with several hearths vertically superposed. Material is raked downward by horizontally rotating rabbles, so as to work alternately to the periphery and center of successive hearths, encountering roasting heat as it gravitates downward. Pryor, 3 multijib cutter A cutter loader with a number of horizontal jibs similar to a coal cutter. Loose coal is diverted onto the conveyor by gummer and plow plate. The machine is usually used in seams up to about 3 ft (0.9 m) in thickness with a clean roof parting. The depth of cut varies up to 4 ft (1.2 m). Coal degradation is considerable. Nelson multilayer bit A bit set with diamonds arranged in successive layers beneath the surface of the crown. CF: impregnated bit; surface-set bit. Long multilock lode Lode that occupies a shear zone. Such a zone has no definite walls, the ore gradually shading off into country rock. It is probable that the gold of some rich alluvial fields came from shear zones. Nelson multilouvre dryer A dryer whose moving element consists of two strands of roller chain with specially designed flights, suspended in such a way as to provide means for keeping the bed in a constantly flowing mass. The material flows in a shallow bed over the ascending flights and at the same time is gradually moved across the dryer from the feed point to the discharge point. The gases are pulled from the furnace and through the flowing bed of 2080

coal. The entire area of the dryer is covered by suction from the exhaust fan. See also: thermal drying multiphase See: polyphase multiple-arch dam A lightweight dam constructed of repeated arches with axes sloping at about 45 degrees to the horizontal, the arches being carried on parallel buttress walls. Hammond multiple-bench quarrying The method of quarrying a rock ledge in a series of successive benches or steps. Fay multiple detectors Two or more seismic detectors whose combined output energy is fed into a single amplifier-recorder circuit. This technique is used to cancel undesirable near-surface waves. Syn: multiple geophones; multiple recording groups. AGI multiple dike A dike made up of two or more intrusions of the same kind of igneous rock. Billings multiple-entry system A system of access or development openings, generally in bituminous coal mines, involving more than one pair of parallel entries, one for haulage and fresh air intake and the other for return air. Multiple-entry systems permit circulation of large volumes of air. multiple-expansion engine An engine driven by steam or compressed air expanding in two or more stages. Hammond multiple fault A structure consisting of several parallel faults in close proximity with no distortion. See also: step fault multiple firing Firing electrically with delay blasting caps in a number of holes at one time. Mitchell 2081

multiple fuse-igniter cartridge Consists of a cardboard cartridge about 2 in long with a 3/4-in (1.9-cm) outside diameter. The closed end is coated with black powder, and the ends of eight fuses are inserted in the cartridge, in contact with the powder. A master fuse is then inserted, which, when lit, burns to the powder and ignites it. The powder flares brightly and lights the eight fuses. South Australia multiple geophones See: multiple detectors multiple intersections a. The intercepts that cross a vein, orebody, or other geologic feature, accomplished by drilling several auxiliary boreholes from a single, main, or parent borehole with the aid of wedges and similar deflecting devices. Long b. Intercepting a steeply dipping vein at various depths by changing the angle of the drill head. multiple intrusion Any type of igneous intrusion that has been produced by several injections separated by periods of crystallization. Chemical composition of the various injections is approx. the same. CF: composite intrusion AGI multiple lines A single line reeved around two or more sheaves so as to increase pull at the expense of speed. Nichols, 1 multiple openings Any series of underground openings separated by rib pillars or connected at frequent intervals to form a system of rooms and pillars. Obert multiple-ply plate Steel plate made up of thicknesses of other plates of steel or steel and wrought iron welded together. Mersereau, 2 multiple recording groups See: multiple detectors multiple ribbon belt conveyor 2082

A belt conveyor having a conveying surface of two or more spaced strands of narrow flat belts. multiple-row blasting The drilling, charging, and firing of several rows of vertical holes along a quarry or opencast face. The holes may be spaced in the square pattern with delay detonators in the rows as well as row by row. The spacing of the holes will vary according to their depth, diameter, and the type of rock. See also: small-diameter blastholes multiple-seam mining Mining two or more seams of coal, frequently close together, that can be mined profitably where mining one alone would not be profitable. Coal Age, 3 multiple seismometers See: bunched seismometers multiple series A method of wiring a large group of blasting charges by connecting small groups in series and connecting these series in parallel. Syn: parallel series multiple shooting The firing of an entire face at one time. The holes are connected in a single series and all the holes shoot at the same instant. Kentucky multiple shot See: battery of holes multiple-shot blasting unit A multiple-shot blasting unit is designed for firing simultaneous explosive charges in mines, quarries, and tunnels. Syn: blasting unit multiple shotholes Two or more shotholes that are shot almost simultaneously. They are so spaced as to minimize near-surface interferences that mask desired signals if only one shothole is used. AGI multiple-shot instrument 2083

A borehole-survey instrument capable of taking and recording a series of inclination and bearing readings on a single trip into a borehole. CF: single-shot instrument multiple-shot survey A borehole survey using a multiple-shot instrument. Long multiple sill A sill made up of two or more intrusions composed of the same kind of igneous rock. Billings multiple-speed floating control system As used in flotation, a form of floating control system in which the manipulated variable may change at two or more rates each corresponding to a definite range of values of the actuating signal. Fuerstenau multiple splitting The parting or separation of a thick seam into more than two layers of coal. See also: simple split seam multiple-strand chain A roller chain made up of two or more strands assembled as a single structure on pins extending through the entire assembly. Jackson, 1 multiple-strand conveyor a. Any conveyor which employs two or more spaced strands of chain, belts, or cords as the load-supporting medium. b. Any conveyor in which two or more strands are used as the propelling medium connecting pans, pallets, etc. multiple-strand rope A wire rope designed to obviate spinning due to untwisting. It is formed by a series of layers of strands built around a center fiber core. Each layer of strands is given a lay opposite to that on which it is built, each layer thus tending to impart its own twist that is cancelled by the next layer. Therefore, this rope can be used for sinking or where a free load is to be lifted. The stretch with a multiple strand rope is not so great as with round strand and flattened strand ropes. See also: multistrand rope; wire rope. Nelson multiple twin 2084

See: repeated twinning multiple-vent basalt See: shield basalt multiple wedge See: plug-and-feather method multiplow A layout consisting of six or more plows, 220 lb (100 kg) each, 20 yd (18.3 m) apart on one rope or chain, feeding onto an armored conveyor; the load on the conveyor is well distributed. A driving unit is arranged at both ends of the face and operated alternately to impart a to-and-fro movement to the plows. The minimum workable seam thickness is 20 in (50.8 cm) at gradients from 0 degrees to 20 degrees ; maximum length of face is about 190 yd (174 m). See also: Gusto multiplow multiplying constant The constant, used in stadia work, by which the staff intercept is multiplied to determine the distance between the staff and the theodolite. The value is generally taken as 100. See also: tachymeter Hammond multirope friction winder A winding system based on the principles of the Koepe winder. The drive to the winding ropes is the frictional resistance between the ropes and the driving sheaves. Multirope friction winders are usually tower mounted, with either cages or skips, and provided with a counterweight. The sheaves are from about 6 to 12 ft (1.8 to 3.7 m) in diameter with a direct coupled or geared drive. Four ropes are favored and these operate in parallel and share the total suspended load. The system was introduced partly because of the difficulty of winding heavy loads from deep shafts with a single large-diameter winding rope. Modern winding ropes have become large and heavy, being 2-1/4 in (5.72 cm) in diameter locked coil, weighing 16.5 st (15 t) for a 1,000-yd (915-m) shaft; therefore, the introduction of the friction winder, with its counterweight, and using four smaller ropes side by side in place of one. Such ropes need be only 1-1/4 in (3.2 cm) in diameter to give equivalent breaking strain. See also: Koepe winder Nelson multishot firing The firing of a number of shots simultaneously. See also: M multishot gyroscopic instrument 2085

A borehole surveying instrument that can take a number of readings during its descent and ascent in the borehole. It comprises gyroscopic and photographic recording units; direction and inclination indicators; a timing clock, and other accessories. A movie film enables numerous records to be taken throughout the depth of the borehole. See also: gelatin borehole tube multispectral scanner A remote sensing device that is capable of recording data in the ultraviolet, visible, and infrared portions of the spectrum. Syn: shuttle multispectral infrared radiometer See also: thematic mapper multistage fan A fan having two or more impellers working in series. BS, 8 multistrand rope A flexible, nonspinning rope; composed of concentric layers of strands of relatively fine wires, alternate layers of strands being wound in opposite directions over a hemp core. See also: multiple-strand rope Sinclair, 5 multiwheel roller A heavy roller with pneumatic tires used to consolidate embankments. Hammond mummification The process of preservation of plant tissues under the influence of arrested decay. Tomkeieff mun Corn. Any fusible metal. mundic A drillers' term for pyrite. See also: pyrite Munroe effect The concentration of explosive effect (i.e. jetting) which occurs at a cavity at the end of an explosive charge; this effect is the basis of the design and performance of shaped charges. 2086

muon Contraction of mu-meson. An elementary particle with 207 times the mass of an electron. It may have a single positive or negative charge. Lyman Murakami's reagent An etching reagent developed for use in the investigation of the structure of iron-carbonchromium alloys. It consists of a solution of 10 g potassium ferricyanide, 10 g potassium hydroxide, and 100 mL water. Osborne murasakite A schistose rock composed of piedmontite and quartz. See also: ollenite AGI murdochite An isometric mineral, PbCu6 O8 (Cl,Br)2 ; rare; secondary; forms minute black octahedra. Murex process A flotation process that is not strictly of the same class as others, but still makes use of the principle of selective oiling of sulfide particles. The crushed ore is fed into an agitator and mixed with 4% to 5% of its weight of a paste made of one part of oil or thin tar with three or four parts of magnetic oxide of iron. This oxide must be ground to an impalpable powder. These ingredients, with enough water to make a pulp, are agitated for 5 to 20 min. The paste preferentially adheres to the sulfides because of the oil. The ore is then fed over magnets, and oxide of iron, with the mineral adhering to it, is pulled out. The oil and magnetite are then recovered. Liddell Muschamp coal miner A cutter loader which is essentiaily a conversion unit for Anderton shearer machines and designed to produce a reasonable percentage of large coal. The top and bottom of the seam are cut by rotating drums of small diameter while shearing the back of the cut with a narrow-kerf jib and chain. Nelson muscovado A term applied in Minnesota to rusty-colored outcropping rocks, such as gabbros and quartzites, that resemble brown sugar. Etymol: Spanish, brown sugar. AGI muscovite 2087

A monoclinic mineral, KAl2 (Si3 Al)O10 (OH,F)2; mica group; pseudohexagonal; perfect basal cleavage; forms large, transparent, strong, electrically and thermally insulating, stable sheets; a common rock-forming mineral in silicic plutonic rocks, mica schists, gneisses, and commercially in pegmatites; also a hydrothermal and weathering product of feldspar and in detrital sediments. Also spelled: moscovite. Syn: isinglass; white mica; potash mica; common mica; Muscovy glass; mirror stone. Sericite is fine-grained muscovite, commonly in connection with hydrothermal alteration, but sericite also includes paragonite and illite. Illite is a common syn. for fine-grained muscovite in clay mineralogy. Muscovy glass See: muscovite mushroom jib A standard form of coal cutter jib with a sprocket at the end remote from the machine. The sprocket carries a vertical turret or bar and is driven by the cutting chain. The bar makes a vertical cut at the back of the normal horizontal cut. See also: turret jib muskeg A bog, usually a sphagnum bog, frequently with grassy tussocks, growing in wet, poorly drained boreal regions, often areas of permafrost. Tamarack and black spruce are commonly associated with muskeg areas. Syn: maskeeg mussel bed A band containing or chiefly composed of mussellike shells, very valuable in the correlation of Coal Measures strata. Mason Musso process A mixture of iron ore and fuel is reduced in an externally heated rotary retort. The gases are exhausted and constitute the fuel when the process has been started. The gases, after purification, are passed through combustion rings surrounding the retort and are burned according to the method of catalytic combustion. After reduction, the charge is cooled when it is poured through a layer of fluxing material; it is then transferred to a steelmaking furnace. Osborne mustard gold A spongy type of free gold found in the gossan above gold-silver-telluride deposits. AGI mutabilite 2088

A soft corklike bitumen of porous or resinous consistency. Partly soluble in organic solvents. Tomkeieff muthmannite A mineral, (Ag,Au)Te ; soft; heavy; gray-white; in tabular crystals with perfect cleavage; an ore mineral. mutu A Malayan term denoting the degrees of fineness of gold. mutual boundary texture A rock texture showing smooth, regular, curved contacts between minerals. Schieferdecker mvb Abbrev. for medium-volatile bituminous. See also: medium-volatile bituminous coal mylonite A compact, chertlike rock without cleavage, but with a streaky or banded structure, produced by the extreme granulation and shearing of rocks that have been pulverized and rolled during overthrusting or intense dynamic metamorphism. Mylonite may also be described as a microbreccia with flow texture. See also: cataclasite; protomylonite; mylonite gneiss; ultramylonite. AGI mylonite gneiss A mylonitic rock that has been partly recrystallized. See also: augen schist; cataclasite; flaser gabbro; mylonite; phyllonite. AGI mylonitization Deformation of a rock by extreme microbrecciation, due to mechanical forces applied in a definite direction, without noteworthy chemical reconstitution of granulated minerals. Characteristically the mylonites thus produced have a flinty, banded, or streaked appearance, and undestroyed augen and lenses of the parent rock in a granulated matrix. Also spelled mylonization. AGI mylonization See: mylonitization 2089

myrickite a. A white or gray chalcedony, opal, or massive quartz unevenly colored by, or intergrown with, pink or reddish inclusions of cinnabar, the color of which tends to become brown. The opal variety is know as opalite. b. Cinnabar intergrown with common white opal or translucent chalcedony. myrmekite An intergrowth of plagioclase feldspar (commonly oligoclase) and vermicular quartz, generally replacing potassium feldspar; formed during the later stages of consolidation in an igneous rock or during a subsequent period of plutonic activity. The quartz occurs as blobs. See: vermicular quartz myrmekite antiperthite Myrmekitelike intergrowth of predominant plagioclase and vermicular orthoclase. The wormlike forms of orthoclase are, as a rule, broader than those of quartz in the typical myrmekite. Schieferdecker myrmekite perthite Myrmekitelike intergrowth of microcline and vermicular plagioclase. Schieferdecker

N N A Diamond Core Drill Manufacturer's Association letter name for a range of diamond drill fittings intended to be used together with the appropriate casing having an inside diameter of 81 mm or somewhat less. Cumming, 2 nablock A rounded mass, as of flint in chalk, or of ironstone in coal. Standard, 2 nacre The hard, iridescent internal layer of various mollusk shells, having unusual luster and consisting chiefly of calcium carbonate in the form of aragonite deposited as thin tablets normal to the surface of the shell and interleaved with thin sheets of organic matrix. Syn: pearly; mother-of-pearl. AGI 2090

nacreous Adj. Applied to the luster of certain minerals, usually on crystal faces parallel to a good cleavage, the luster resembling that of pearls. CMD nacrite A monoclinic mineral, Al2 Si2 O5 (OH)4 ; kaolinite-serpentine group; differs from other kandites, such as triclinic kaolinite and monoclinic dickite, in the stacking order of its layers (polytypy); fine-grained, massive; commonly associated with hydrothermal alteration. nadir a. The point on the celestial sphere that is directly beneath the observer and directly opposite the zenith. AGI b. The point on the ground vertically beneath the perspective center of an aerial-camera lens. AGI nadorite An orthorhombic mineral, PbSbO2 Cl ; an uncommon secondary mineral; in resinous to adamantine crystals in some base-metal deposits. naetig Industrial diamond having a grain in all directions instead of in regular layers. CF: feinig nagyagite A possibly orthorhombic mineral, Pb5 Au(Te,Sb)4 S5-8; occurs with other tellurides in lamellar, soft, heavy, lead-gray crystals; one perfect cleavage but may form anhedral masses. Syn: black tellurium nahcolite A monoclinic mineral, NaHCO3 ; forms small, white, highly soluble, prismatic crystals; in nonmarine evaporite deposits; esp. abundant in parts of the Green River lake beds of Colorado. naif adj. Said of a gemstone having a true or natural luster when uncut; e.g., of the natural, unpolished faces of a diamond crystal. Also spelled naife. nail 2091

a. See: shooting needle b. A slender piece of metal, one end of which is pointed, the other end having a head, either flattened or rounded. It is a common means of fastening together several pieces of wood or other material by striking the head with a hammer. The term penny as applied to nails refers to the number of pounds per 1,000 nails; e.g., six-penny nail means 6 lb (2.7 kg) per 1,000; three-penny means 3 lb (1.4 kg) per 1,000, etc. Crispin nailhead spar A composite variety of calcite having the form suggested by the name. Fay naked See: bare; blank hole. name of lode The name by which a lode is designated in the notice of location, and subsequent addition thereto is immaterial. The same vein or lode may have different names in different mining locations. Ricketts nanotesla See: gamma Nansen bottle An oceanographic water-sampling bottle, made of a metal alloy that is little reactive with seawater, equipped with a rotary valve at each end so that when it is rotated at depth the valves close and lock shut, entrapping a water sample and setting the reversing thermometers. This bottle is named for its designer, Fridtjof Nansen. Hy nantokite An isometric mineral, CuCl ; granular, massive; cubic cleavage; adamantine luster; an uncommon secondary mineral in copper deposits. naphtha a. An archaic term for liquid petroleum. AGI b. Designates those hydrocarbons of the lowest boiling point (under 250 degrees C) that are liquid at standard conditions, but easily vaporize and become flammable. They are used as cleaners and solvents. AGI naphtha gas 2092

Illuminating gas charged with the decomposed vapor of naphtha. Standard, 2 naphthode Concretion of bituminous limestone rich in carbonaceous matter. Tomkeieff Napierian logarithm A natural logarithm. Webster 3rd napoleonite A variety of hornblende. Standard, 2 nappe a. A sheetlike, allochthonous rock unit, which has moved on a predominantly horizontal surface. The mechanism may be thrust faulting, recumbent folding, or both. The term was first used for the large allochthonous sheets of the western Alps, and it has been adopted into English. The German equivalent, decke, is also sometimes used in English. Etymol: French, cover sheet, tablecloth. Syn: decke AGI b. Belg. See: aquifer napthoid Liquid petroleumlike product found in cavities of igneous rocks and assumed to be a product of thermal distillation of bituminous substances contained in the country rocks. Tomkeieff narrow a. A roadway driven in the solid coal with rib sides. All roadways when opening out a pillar method of working are narrow. See also: working the whole b. N. of Eng. A gallery, or roadway, driven at right angles to a drift, and not quite so large in area. Fay narrow gage A railway gage narrower than the standard gage of 4 ft 8-1/2 in (1.44 m). Hammond narrow place Aust. Working place that is less than 6 yd (5.5 m) wide; these are paid for by the yard in length. Fay narrow stall 2093

A stall driven in solid coal, usually from 6 to 9 ft (1.8 to 2.7 m) wide; it has rib sides in coal. See also: rib-side; solid road. Nelson narrow work a. The driving of narrow stalls to form coal pillars as the first stage in the pillar-and-stall method of working. Nelson b. A system of mining in which narrow coal roadways, called endings, are driven along the strike of the seam, from 12 to 15 yd (11.0 to 13.7 m) apart, to a limit line. The long narrow coal pillars between the endings are extracted on the retreat. It has been adopted in parts of Yorkshire and Lancashire, England. See also: endings; main endings. Nelson c. All work for which a price per yard of length driven is paid, and which, therefore, must be measured. Any dead work. Fay d. Penn. Headings, chutes, crosscuts, gangways, etc., or the workings previous to the removal of the pillars. Fay e. A working place in coal only a few yards in width. Fay narrow working See: bord-and-pillar method; narrow work. nascent Just formed by a chemical reaction, and therefore very reactive. Nascent gases are probably in an atomic state. CTD Nasmyth hammer A steam hammer, having the head attached to the piston rod, and operated by the direct force of the steam. Fay Na-spar See: soda spar National coarse thread The screw thread of common use, formerly known as the United States Standard thread. Crispin National Electrical Code A set of rules to guide electricians when installing electrical conductors, devices, and machinery. Crispin national grid 2094

Gr. Brit. A system of rectangular coordinates used by the Ordnance Survey and based upon the Transverse Mercator Projection (which is also known as the Gauss Conformal Projection). BS, 7 national grid coordinates Gr. Brit. Coordinates, referred to the National Grid of the Ordnance Survey, which are specified in meters and consist of two components, an Easting and a Northing. BS, 7 Nationalization Act The Coal Industry Nationalization Act, 1946, which brought all coal mines in the United Kingdom under public ownership. It was passed through Parliament in JuIy 1946 and put into operation on January 1, 1947. Nelson National Physical Laboratory British government organization that, among other things, tests and certifies calibration of scientific glassware, weights, and measures. Abbrev. NPL. Pryor, 3 native a. Occurring in nature, either pure or uncombined with other substances. Usually applied to metals, such as native mercury, native copper. Also used to describe any mineral occurring in nature in distinction from the corresponding substance formed artificially. b. Adj. Applied to earth materials occurring in elemental form; e.g., nugget gold, metallic copper. Syn: native element native copper a. Metallic copper, sometimes containing a little silver and bismuth, that occurs as a metasomatic deposit filling cracks and forming the cement of sandstone and conglomerate. Such deposits have been found in the Keweenaw Peninsula, Lake Superior, MI, USA; Chile; Queensland, Australia; and Zimbabwe. Native copper is also found in the upper workings of copper mines. b. A mineral in the form of particles and nuggets of very pure metallic copper associated (but not alloyed) with small amounts of silver and arsenic minerals. It is found in small amounts in many copper ores but occurs in commerical quantities in only one place in the world, the Upper Peninsula in Michigan. See also: copper native element Element that occurs in nature uncombined, such as nugget gold, metallic copper, etc. See also: native 2095

native mercury See: quicksilver native nickel-iron See: awaruite; josephinite. native water See: formation water natrite A monoclinic mineral, NaCO3 ; occurs in very soluble, white, granular masses; a rare mineral in the alkalic complexes of the Kola peninsula, Russia. natrium See: sodium natrochalcite A monoclinic mineral, NaCu2 (SO4 )2 (OH).H2 O; bright emerald-green; forms steep pyramidal crystals; a secondary copper mineral at Chuquicamata, Chile. natrojarosite A trigonal mineral, NaFe3+3 (SO4 )2 (OH)6 ; alunite group; in earthy masses and minute scales; a common alteration product in pyrite-bearing deposits. Formerly called utahite. natrolite An orthorhombic mineral, Na16 [Al16 Si24 O80].16H2 O; zeolite group, which may contain appreciable calcium; dimorphous with tetranatrolite; forms acicular to slender prismatic crystals in cavities and veins, esp. in mafic and alkaline igneous rocks. Syn: laubanite natromontebrasite A triclinic mineral, (Na,Li)Al(PO4 )(OH,F) ; amblygonite group; in granitic pegmatites associated with other lithium minerals. Formerly called fremontite. natron

2096

A monoclinic mineral, Na2 CO3 .10H2 O ; very soluble; forms earthy or granular crusts and efflorescences; in nonmarine evaporites and on lavas. natrona See: sodium sesquicarbonate natron granite Granite abormally high in soda, presumably from the presence of a soda-rich orthoclase or of anorthoclase. It is also called soda granite. nattle Eng. To make a slight rattling or tapping noise. Said of a mine when movement or settling is taking place. Webster 3rd; Fay natural air crossing An air crossing in which two airways are separated by rock in its natural state. BS, 8 natural asphalt Asphalt before crushing or refining, as mined or quarried in the case of natural rock asphalt, or surface-excavated in the case of lake deposits. Hammond natural carbon Carbon found in a shape that has not been artificially modified. Also called natural stone. Long natural cement A hydraulic cement produced by pulverizing and then heating naturally occurring rock (cement rock) containing appropriate proportions of limestone, clay, magnesia, and iron. Ignition temperatures are usually lower than for portland cement. Final pulverizing is necessary as with portland cement. natural coke Coke made by natural processes, usually by the intrusion of an igneous dike. See also: cinder coal; clinker; coke coal; cokeite. Hess natural convection 2097

See: convection natural diamond This abrasive is the densest form of crystallized carbon, the hardest substance known. It occurs most commonly as well-developed crystals in volcanic pipes or in alluvial deposits. Bort (boart or borts) sometimes refers to all diamonds not suitable for gems, or it may refer to off-color, flawed, or impure diamonds not fit for use for gems or most other industrial applications, but suitable for the preparation of diamond grain and powder for use in lapping or the manufacture of most diamond grinding wheels. This type of bort is also called crushing bort or fragmented bort. ACSG, 2 natural Earth current Electric current in the Earth not due to human activity. Schieferdecker natural face A name given to the X direction as pencilled on Z sections of unfaced quartz and whose position is determined by X-ray measurements or etching. The name is also given to the artificial prism face (parallel to 1120) thus located, and produced by sawing the section in the YZ plane. Also applied to the natural growth faces on faced raw quartz crystals. Am. Mineral., 2 natural floatability See: inherent floatability natural frequency The frequency of free oscillation of a system. For a multiple-degree-of-freedom system, the natural frequencies are the frequencies of the normal modes of vibration. Hy natural frequency of a foundation The frequency of free vibration of a complete soil-foundation oscillating system. This frequency must differ distinctly from that of any machinery carried by the foundation if resonance is to be avoided. Hammond natural frequency vibrating conveyor A vibrating conveyor in which the rate of free vibration of the trough on its resilient supports is approx. the same as the rate of vibration induced by the driving mechanism. natural gamma radiation detector 2098

This is a type of sensor that measures bursts of high-energy electromagnetic waves that are emitted spontaneously by some naturally occurring radioactive elements, such as potassium-40, thorium-232, and uranium-238, that are commonly present in shales and clays. Mowrey natural gamma-ray logging A process whereby gamma rays naturally emitted by formations traversed by a borehole are measured. A tool containing a radiation detector is lowered into the borehole and gamma ray measurements are transmitted to the Earth's surface. The signals are utilized to produce a record of gamma rays detected in correlation with the depth of the detector in the borehole. The record thus obtained in the form of a curve indicating relative number per unit of time of natural gamma rays at different depths, is a conventional natural gamma-ray log, sometimes simply called a gamma-ray log. Williams natural gas A mixture of the low-molecular-weight paraffin series hydrocarbons methane, ethane, propane, and butane, with small amounts of higher hydrocarbons; also frequently containing small or large proportions of nitrogen, carbon dioxide, and hydrogen sulfide, and occasionally small proportions of helium. Methane is almost always the major constituent. Natural gas accompanying petroleum always contains appreciable quantities of ethane, propane, butane, as well as some pentane and hexane vapors, and is known as wet gas. Dry gas contains little of these higher hydrocarbons. The exact composition of natural gas varies with locality. The heating value of natural gas is usually over 1,000 Btu/ft3 unless nitrogen or carbon dioxide are important components of the gas. See also: gas; sour gas. CCD, 2 natural glass A vitreous, amorphous, inorganic substance that has solidified from magma too quickly to crystallize. Granitic or acid natural glass includes pumice and obsidian; an example of a basaltic natural glass is tachylite. AGI natural logarithm A logarithm with e as a base. Webster 3rd naturally bonded molding sand A term used by foundrymen to refer to a sand that, as mined, contains sufficient bonding material for molding purposes. Osborne natural ore 2099

a. In iron mining, the term given to naturally occurring high-grade iron ore; consists of: (1) soft ore, such as porous hematite and limonite (goethite) with minor magnetite and manganese oxides; and (2) hard ores, such as compact, fine-grained, steel-gray hematite, specular hematite, magnetite, or martite. Syn: direct shipping ore b. Iron ore that contains moisture, in contrast to "dry ore" that has been dried but not calcined. USBM, 7 c. A term used in the U.S. Lake Superior mining district to indicate iron ore formed by natural processes, as distinguished from iron ore products (such as pellets) produced artificially from hard, low-grade ores of the taconite type. Published prices for natural ores from this district usually specify iron content as "natural," meaning that the analysis is based on gross weight including moisture. Syn: lump ore; silicious ore; high-silica ore; wash ore; heavy-media ore; manganiferous ore; natural ore concentrate; lean ore; paint-rock ore; Mesabi non-Bessemer ore. natural ore concentrate See: natural ore natural paper Brownish paperlike deposit formed from the filaments of Conferva. Tomkeieff natural resin See: resin natural sand Sand derived from a rock, in which the grains separate along their natural boundaries. This includes unconsolidated sand or a soft sandstone where little pressure is required to separate the individual grains. Osborne natural scale Applied to a drawing made to equal vertical and horizontal scales. Hammond natural slope The maximum angle at which loose material in a bank or spoil heap will stand without slipping. See also: angle of rest; angle of slide. Nelson natural splitting In mine ventilation, a practice that allows the airflow to divide among the branches of its own accord and without regulation, in inverse relation to the resistance of each airway. CF: controlled splitting Hartman, 2 2100

natural stress relief The failure of the skin rock of an excavation by crushing, shear, or plastic flow. It can occur on free surface rock with explosive force. See also: arching natural ventilating pressure a. In a mine, air returning from the workings to the surface via the upcast shaft can be of a higher temperature than the air in the downcast shaft because of heat added to the ventilation current from the strata exposed in the mine. Thus, even in a mine with the fan stopped, the upcast air density is less than the downcast air density. This lack of balance in the two vertical air columns produces a pressure difference across the shaft bottom doors known as natural ventilating pressure. Roberts, 1 b. The ventilating pressure that produces natural ventilation. BS, 8 natural ventilation The ventilation produced in a mine as a result of a difference in density of the air in the upcast and downcast shafts, brought about by natural causes. Natural ventilation is feeble, seasonal, and inconstant. Nelson nauckite A variety of resin. Tomkeieff naumannite An orthorhombic mineral, Ag2 Se ; pseudocubic; black; lustrous; forms heavy, sectile granular masses; also in thin plates; epithermal; a major source of silver in some deposits. nautical chart A representation on a horizontal plane, and according to a definite system of projection, of a portion of the navigable waters of the Earth, including the shorelines, the topography of the bottom, and aids and dangers to navigation; it may be derived from hydrographic, topographic, or aerial surveys, or a combination thereof. Seelye, 2 nautical measure One nautical mile or knot equals 6,080.20 ft (1,853.248 m); 3 nmi equal 1 league; and 60 nmi equal 1 degree of longitude (at the equator). Crispin nautical mile 2101

Any of various units of distance, used for sea and air navigation, based on the length of a minute of arc of a great circle of the Earth and differing because the Earth is not a perfect sphere: (1) a British unit that equals 6,080 ft or 1,853.2 m; also called Admiralty mile; (2) a U.S. unit, no longer in official use, that equals 6080.20 ft or 1,853.248 m; and (3) an international unit that equals 6,076.1033 ft or 1,852 m; used officially in the United States since July 1954. Webster 3rd navajoite A monoclinic mineral, (V,Fe)10 O24 .12H2 O ; rare; weakly radioactive; soft; a fibrous mineral with a silky luster; associated with corvusite, hewettite, tyuyamunite, rauvite, steigerite, and limonite. Navier's hypothesis An assumption in the design calculation of beams. It states that the stress at any point due to bending is assumed as being proportional to its distance from the neutral axis. Hammond NCB The National Coal Board of the United Kingdom. Nelson NCB boring tower A boring tower developed by the National Coal Board of the United Kingdom to make test drillings for coal from positions off the coast. When drilling is in progress, the tower is resting on the seabed. The base is divided into four airtight sections, which are filled with water when the tower is in position for drilling. The water is pumped out to give buoyancy when the tower is refloated for towing to a new drilling site. The tower is designed to withstand gales of 80 mph (128 km/h) and waves of 30 ft (9.1 m) from crest to trough, and it can be used in any depth of water up to 120 ft (36.6 m). The overall height of the tower is 189 ft (57.6 m), and its total weight is about 570 st (517 t). It has reached over 3,000 ft (915 m) drilling depth with core recovery. The first borehole was put down in the Firth of Forth, Scotland. Nelson NCB recorder This butane combustible gases recorder has a small flame of burning butane gas, which is controlled to give constant heat output with varying ambient temperature and humidity, and with varying butane gas pressure. The heat output is measured by means of a group of thermocouples in a chimney above the flame. The presence of methane in the atmosphere, which has access to the flame via suitable gauzes, increases the voltage generated by the thermocouples. These changes are recorded on a rotating chart calibrated in percentage methane. Roberts, 1 2102

neap tide In oceanography, a high tide occurring at the moon's first or third quarter, when the sun's tidal influence is working against the moon's, so that the height of the tide is below the maximum in the approximate ratio of 3:8. CTD nearest neighbor interpolation method A method of assigning a sample value to a point in space. The value assigned is equal to the value of the spatially nearest sample data point. This method is sometimes used as a computer equivalent of the polygonal method of interpolation. near-gravity material A washability term popularly defined as the percentage of material in the raw coal within + or -0.1 of the separating specific gravity. Nelson near-mesh Near-sized; grains close in cross section to a specified screening mesh, which tend to blind apertures and slow down sizing. Syn: near-mesh material near-mesh material Material approximating in size to the mesh aperture. BS, 5 neat Cement slurries containing no aggregate, such as sand or gravel. Syn: neat cement neat cement A slurry composed of any cement and water. Syn: neat cement Brantly, 1 neat lines The excavation lines of a tunnel within which the rock removed is paid for at the agreed contract rate. See also: overbreak nebulite A type of mixed rock whose fabric is characterized by indistinct, streaky inhomogeneities or schlieren and in which no sharp distinction can be made between the component parts of the fabric. Adj: nebulitic. AGI 2103

neck a. A lava-filled conduit of an extinct volcano exposed by erosion; also called chimney rock or plug. See also: plug b. A pipe of igneous rock crossing bedding planes. Mason c. The narrow entrance to a room next to the entry, or a place where the room has been narrowed on account of poor roof. Fay d. A narrow stretch of land, such as an isthmus or a cape. Webster 3rd e. A narrow body of water between two larger bodies; a strait. Webster 3rd needle a. A piece of copper or brass about 0.5 in (1.3 cm) in diameter and 3 ft or 4 ft (0.9 m to 1.2 m) long, pointed at one end, and turned into a handle at the other, tapering from the handle to the point. It is thrust into a charge of blasting powder in a borehole, and while in this position the borehole is tamped solid, preferably with moist clay. The needle is then withdrawn carefully, leaving a straight passageway through the tamping for the miner's squib to shoot or fire the charge. Fay b. A timber set on end to close an opening for the control of water; it may be either vertical or inclined; a form of stop plank. Seelye, 1 c. A small metal rod for making the touchhole in the powder used for blasting. d. A hitch cut in the side rock to receive the end of a timber. e. A needle-shaped or acicular mineral crystal. needle bearing An antifriction bearing using very small-diameter rollers between wide faces. Nichols, 1 needled Pocketed, as when face bars are set with the face end of the bar pocketed into the coal adjacent to the roof. TIME needle instrument Any surveying instrument controlled by a magnetic needle. See also: compass needle ore a. Iron ore of very high metallic luster, found in small quantities, which may be separated into long, slender filaments resembling needles. AGI b. See: aikinite needles Elongated crystals, tapering at each end to a fine point, as those typical of martensite. Rolfe 2104

needle traverse In a survey with a dial (compass), use of a magnetic needle to read the bearing of lines. Opposite is fast needle traverse or work, and refers to the use of a dial as in traversing with a theodolite, where proximity of iron might deflect the needle. Systems can be combined, using needle readings where iron is absent. Also called swinging needle traverse; loose needle traverse. Pryor, 3 negative crystal a. A birefringent crystal in which the refractive index of the extraordinary ray is less than that of the ordinary ray. b. A cavity within a crystal bounded by the crystal faces of that crystal. See also: inclusion; three-phase inclusion. negative element A large structural feature or portion of the Earth's crust, characterized through a long period of geologic time by frequent and conspicuous downward movement (subsidence, submergence), extensive erosion, or an uplift that is considerably less rapid or less frequent than those of adjacent positive elements. AGI negative elongation Lathlike, rodlike, or acicular crystals in which the slow polarized light ray lies across the long direction of the crystal. CF: positive elongation negative moment See: hogging moment negative rake a. The orientation of a cutting tool in such a manner that the angle formed by the leading face of the tool and the surface behind the cutting edge is greater than 90 degrees . Syn: drag rake See also: gouge angle b. Describes a tooth face in rotation whose cutting edge lags the surface of the tooth face. CF: rake negligence In a legal sense, a failure upon the part of a mine operator to observe for the protection of the interests of the miner that degree of care, precaution, and vigilance that the circumstances justly demand, whereby the miner suffers injury. Ricketts neighborite 2105

An orthorhombic mineral, NaMgF3 ; insoluble; forms rounded grains or pseudooctahedral crystals; associated with dolomite and quartz in oil shale within the Green River Formation, UT. nekton A biological division made up of all the swimming animals found in the pelagic division. Hy Nelson Davis separator A cylindrical dense-medium washer developed in the United States. It uses a magnetite water suspension as medium. The bath resembles a drum in shape, its longitudinal axis being horizontal; within the stationary outer casing there is a rotor divided into compartments. Raw coal is fed near the top of the separator, and separation takes place as the rotor revolves. The machine produces clean coal and shale; the magnetite is recovered. It can handle coal up to 10 in (254 mm) in size, the lower limit being about 1/4 in (6.4 mm). Magnetite consumption runs at about 1/2 lb/st (0.25 kg/t) of feed. See also: Leebar separator nelsonite A rock composed essentially of ilmenite and apatite, with or without rutile. The ratio of ilmenite to apatite varies widely. CF: ilmenitite nematoblastic Pertaining to the texture of a recrystallized rock in which the shape of the grains is threadlike. See also: fibroblastic neokerogen Organic debris deposited among marine sediments and modified by bacterial action in such a way as to form the source material of petroleum, or, under certain conditions, to form the kerogen of oil shales. Tomkeieff neolite A silky, fibrous, stellated, green, hydrous magnesium-aluminum silicate. Standard, 2 Neolithic In archaeology, the last division of the Stone Age, characterized by the development of agriculture and the domestication of farm animals. Correlation of relative cultural levels 2106

with actual age (and, therefore, with the time-stratigraphic units of geology) varies from region to region. Adj: pertaining to the Neolithic. AGI neomesselite See: messelite neomineralization Chemical interchange within a rock whereby its mineral constituents are converted into new mineral species; a type of recrystallization. AGI neomorphic Said of the mineral grains of a rock that have been regenerated by zones of secondary growth in crystalline continuity. The new material may have been deposited from solutions or from molten fluids. neoprene plug closure The function of the neoprene plug is to provide a completely waterproof seal at the open end of the detonator. Moisture penetration could cause desensitization of the explosive charge in the detonator, and in the case of copper-tubed detonators, moisture could produce a potentially dangerous chemical reaction between the lead azide and the copper. McAdam, 2 nepheline A hexagonal mineral, (Na,K)AlSiO4 ; feldspathoid group; greasy luster; forms glassy crystals, colorless grains, coarse crystals with prismatic cleavage, or masses without cleavage; occurs in alkalic igneous rocks; an essential constituent of some sodium-rich rocks, e.g., nepheline syenite. Formerly called nephelite; eleolite. nepheline syenite A plutonic rock composed essentially of alkali feldspar and nepheline. It may contain an alkali ferromagnesian mineral, such as an amphibole (riebeckite, arfvedsonite, barkevikite) or a pyroxene (acmite or acmite-augite); the intrusive equivalent of phonolite. Sodalite, cancrinite, hauyne, and nosean, in addition to apatite, sphene, and opaque oxides, are common accessories. Rare minerals are also frequent accessories. Syn: foyaite; eleolite syenite; midalkalite. AGI nephelinite

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A fine-grained or porphyritic extrusive or hypabyssal rock, of basaltic character, but primarily composed of nepheline and clinopyroxene, esp. titanaugite, and lacking olivine and feldspar. AGI nephelinitoid A nepheline-rich groundmass in an igneous rock; the glassy groundmass in nepheline rocks. AGI nephelinization The process of introduction of or replacement by nepheline. AGI nephelometry The measurement of the cloudiness of a medium; esp. the determination of the concentration or particle sizes of a suspension by measuring, at more than one angle, the scattering of light transmitted or reflected by the medium. CF: turbidimetry nephrite An exceptionally tough, compact, fine-grained, greenish or bluish variety of amphibole (specif. tremolite or actinolite) constituting the less rare or valuable kind of jade. Syn: kidney stone; greenstone. neptunian dike A dike filled by sediment, generally sand, in contrast to a plutonic dike filled by volcanic materials. See also: sand dike neptunian theory See: neptunism neptunism The theory, advocated by A. G. Werner in the 18th century, that the rocks of the Earth's crust all consist of material deposited sequentially from, or crystallized out of, water. Etymol: Neptune, Roman god of waters. CF: plutonism neptunite A monoclinic mineral, KNa2 Li(Fe,Mn)2 Ti2 Si8 O24 ; forms red to black prismatic crystals; occurs in late stages of reduced, silica-deficient environments; e.g., alkaline igneous rocks and veins in serpentinite. See also: mangan-neptunite 2108

neritic Pertaining to the shallow seas; for accumulations of shells, but sometimes for the whole environment of deposition on the continental shelf. Challinor neritic zone That part of the sea floor extending from the low tide line to a depth of 200 m. Nernst film In ion exchange, the diffusion-layer supposed to surround a bead of resin. This static film is reduced, or diffusion through it is accelerated, if agitation of the ambient liquor is increased, if temperature is raised, or if concentration of ions in solution is made greater. Pryor, 3 nero-antico A black marble found in Roman ruins, probably from the Taenarian peninsula, Greece. nesquehonite An orthorhombic mineral, Mg(HCO3 )(OH).2H2 O ; forms low-temperature efflorescences, particularly as an alteration product of lansfordite. Named for a coal mine at Nesquehoning, PA. ness A British term used esp. in Scotland for a promontory, headland, or cape, or any point or projection of the land into the sea; commonly used as a suffix to a place name, e.g., Fifeness. Also called nose. AGI nest a. A concentration of some relatively conspicuous element of a geologic feature, such as a nest of inclusions in an igneous rock or a small, pocketlike mass of ore or mineral within another formation. AGI b. A fitting of the next-smaller-size casing inside the casing already set in a borehole, or of one tube inside another. nested variogram model A model that is the sum of two or more component models, such as nugget, spherical, etc. Adding a nugget component to one of the other models is the most common nested model, but more complex combinations are occasionally used. 2109

net a. Scot. Strapping used for lowering or raising horses in shafts. Fay b. A plane of points each with identical point surroundings. CF: space lattice; lattice. net calorific value The heat produced by combustion of unit quantity of a solid or liquid fuel when burned, at a constant pressure of 1 atm (0.1 MPa), under conditions such that all the water in the products remains in the form of vapor. Net heat of combustion at constant pressure is expressed as Qp (net). ASTM net-corrected fill Net fill after making allowance for shrinkage during compaction. Nichols, 1 net cut The amount of excavated material to be removed from a road section, after completing fills in that section. Nichols, 1 net drilling time The rotating time actually spent in deepening a borehole. (Long, 1960) net fill The fill required, less the cut required, at a particular station or part of a road. Nichols, 1 nether The lower part of, as in nether roof; opposite of the term "upper." TIME nether roof a. The strata directly over a coal seam. The props set at the face hold only the nether roof. E.g., if the props carry a load of 20 st (18.1 mt) each and are set 4 ft (1.2 m) apart each way, the supported weight is 1.5 st/ft2 (14.6 t/m2 ). See also: underweight; absolute roof; overarching weight; immediate roof. Nelson b. In mine subsidence, the immediate roof of limited depth, such as timber might be expected to support. Briggs nether strata The roof and strata immediately above the coal. Mason 2110

net slip On a fault, the distance between two formerly adjacent points on either side of the fault, measured on the fault surface or parallel to it. It defines both the direction and relative amount of displacement. AGI net texture See: network structure Nettleton method An indirect means of density determination in which a closely spaced gravity traverse is run over some topographic feature, such as a small hill or valley. When the profile of observed values is plotted, the gravitational effect of the feature itself is calculated at each observation point along the profile and removed from the observed value for that point. The calculation is repeated a number of times, different densities being assumed for each computation. The density value at which the hill is least conspicuous on the gravity profile is considered to be most nearly correct. Dobrin net unit value The difference between the gross unit recoverable value and the cost of mining, treating, and marketing ore; in other words, the net operating profit. See also: gross recoverable value; gross unit value. Nelson network a. Esp. in surveying and gravity prospecting, a pattern or configuration of stations, often so arranged as to provide a check on the consistency of the measured values. AGI b. In ventilation surveys, the multiple development openings, haulage ways, and working faces that constitute the ventilation system of a mine. Hartman, 2 network deposit See: stockwork network structure A structure in which one constituent occurs primarily at the grain boundaries, thus partially or completely enveloping the grains of the other constituent. Syn: net texture Neuenburg saw

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A plow consisting of a 2-in (5.1-cm) steel plate 6 ft by 20 in (1.8 m by 50.8 cm) of seven pieces hinged together to follow floor rolls; picks on the face edge cut in both directions. The minimum workable seam is 14 in (35.6 cm) on gradients of 35 degrees to 70 degrees . Maximum face length is 80 yd (73.2 m). The machine is used in the Ruhr. Nelson neuk The tailgate corner of a face behind the face conveyor tension end. Trist Neumann lamellae Straight, narrow bands parallel to the crystallographic planes in the crystals of metals that have been subjected to deformation by sudden impact. They are actually narrow twin band, and are most frequently observed in iron. CTD neuropteris A large tree-fern of the coal forest, with trunks about 2 ft (0.6 m) thick, containing several cylinders of wood inside the stem instead of one column of wood as in modern trees. Nelson neutral atmosphere Atmosphere in which there is neither an excess nor a deficiency of oxygen. neutral axis The line of zero fiber stress in any given section of a member subject to bending; it is the line formed by the intersection of the neutral surface and the section. Roark neutral equilibrium A body is said to be in neutral equilibrium if on being slightly displaced it remains in its new position; e.g., a ball placed on a horizontal surface or a cone supported on its side on a horizontal surface. Morris neutralize To add either an acid or alkali to a solution until it is neither acid nor alkaline. Gordon neutral lining Furnace lining of neutral refractories. Osborne neutral point 2112

a. A neutral point in a wye-connected alternating-current power system means the connection point of transformer or generator windings from which the voltage to ground is nominally zero, and which is the point generally used for system grounding. b. In titration, the point at which hydrogen ions and hydroxyls are approx. balanced, each at about 1 times 10-7 molar. Since color-change-indicating dyes do not all react at this point, selection for a given titration must be made with regard to the required point of change. Pryor, 3 neutral pressure The hydrostatic pressure of the water in the pore space of a soil. See also: pore-water pressure; pore pressure; neutral stress. Hammond neutral refractory a. A refractory that is neither strongly basic nor strongly acid, such as chrome, mullite, or carbon. ARI b. A refractory that is resistant to chemical attack by both acid and basic slags, refractories, or fluxes at high temperatures. ASTM neutral salt A salt in which all the hydrogen of the hydroxyl groups of an acid is replaced by a metal. Standard, 2 neutral salt effect Reduction of ionization of a weak acid or base by addition of ionizing salt that contains one of the ions already present; form of common ion effect. Pryor, 3 neutral stress The stress transmitted by the fluid that fills the voids between particles of a soil or rock mass; e.g., that part of the total normal stress in a saturated soil caused by the presence of interstitial water. Syn: pore pressure; pore-water pressure; neutral pressure. AGI neutral surface The longitudinal surface of zero fiber stress in a member subject to bending; it contains the neutral axis of every section. Roark neutral zone A strain-free area. CF: compression zone; tension zone. Nelson neutron 2113

An uncharged elementary particle with a mass that nearly equals that of the proton. An isolated neutron is unstable and decays with a half-life of about 13 min into an electron, a proton, and a neutrino. Neutrons sustain the fission chain reaction in a nuclear reactor. Lyman neutron density The number of neutrons per cubic centimeter. Lyman neutron-gamma log A radioactivity log employing both gamma and neutron-log curves. The neutron log should respond best to porous fluid-filled rock and the gamma best to shale markers. AGI neutron log Strip recording of the secondary radioactivity arising from the bombardment of the rocks around a borehole by neutrons from a source being caused to move through the borehole. Used, generally in conjunction with other types of logs, for the identification of the fluidbearing zones of rocks. See also: radioactivity log; neutron logging. Inst. Petrol.; AGI neutron logging A radioactivity logging method used in boreholes in which a neutron source provides neutrons that enter rock formations and induce additional gamma radiation, which is measured by use of an ionization chamber. The gamma radiation so induced is related to the hydrogen content of the rock. AGI Nevadan orogeny Late Jurassic-Early Cretaceous diastrophism in Western North America. nevyanskite A former name for iridosmine. See also: iridosmine Newark Supergroup Continental strata of Lower Jurassic or Upper Triassic age in the Eastern United States, consisting essentially of red sandstone, shale, arkose, and conglomerate, some 14,000 to 18,000 ft (4.3 to 5.5 km) thick. The series includes black shales with fish remains, thin coal seams in Virginia and North Carolina, and basaltic flows and sills. CTD Newaygo screen 2114

A slanting screen in which the material to be screened passes down. The screen is kept in vibration by the impact of a large number of small hammers. Liddell newjersite Variety of resin. Tomkeieff Newlyn datum The mean sea level now used as the British Ordnance Datum for leveling. It was determined as the result of several years' observations at Newlyn, Cornwall, England, and differs at various places by more than 0.3 m from levels based on the Liverpool datum, which it supersedes. Hammond Newmann hearth A modified Scotch hearth in which poking or rabbling is done mechanically. CTD new miner training In mining, mandatory training given the miners having no previous mining experience; includes instruction in the statutory rights of miners and their representatives, use of selfrescue devices and respiratory devices where appropriate, hazard recognition, emergency procedures, electrical hazards, first aid, walk around training, and other health and safety aspects of the tasks to which the person will be assigned. CF: refresher training; task training. Federal Mine Safety new sand Newly mixed, but not unused, molders' sand. Standard, 2 new scrap The material generated in the manufacturing process of articles for ultimate consumption; it includes defective castings, clippings, turnings, borings, drosses, slags, etc., that are returned directly to the manufacturing process or sold directly for reprocessing. Newtonian fluid Term marking the distinction, made in mineral processing that involves agitation, between a truly viscous (Newtonian) liquid and one in which shear or apparent viscosity (pseudoviscosity) varies with the dimensions of the containing system and the speed of agitation. The latter type of fluid is said to be non-Newtonian. Pryor, 3 2115

Newton's law of gravitation See: law of gravitation New York rod A leveling rod marked with narrow lines, ruler fashion. Nichols, 1 N-frame brace A diagonal brace in a square set. Fay ngavite A chondritic stony meteorite composed of bronzite and olivine in a friable, breccialike mass of chondrules. AGI niccolite A former name for nickeline. Also spelled nicolite. Syn: arsenical nickel; copper nickel. Nicholls' technique A technique used in the determination of elastic constants of rock in situ. Longitudinal and shear waves are generated in rock by small explosive charges in shallow drill holes. Accelerometers and strain gages are employed to measure arrival times for both waves. From wave velocities and measured density, Poisson's ratio, modulus of elasticity, modulus of rigidity, Lame's constant, and bulk modulus can be calculated. Lewis nickel a. An isometric mineral, elemental Ni; hard; metallic; silver-white; a native metal, esp. in meteorites; also alloyed with iron in meteorites. b. A silvery white, hard, malleable, ductile, somewhat ferromagnetic element. Symbol: Ni. It takes on a high polish and is a fair conductor of heat and electricity. Used for making stainless steel and other corrosion-resistant metals and is chiefly valuable for the alloys it forms. Also used extensively in coinage, in desalination plants for converting sea water into fresh water, and in making nickel steel for armor plate and burglar-proof vaults. Handbook of Chemistry and Physics, 3 nickel antimony glance Sulfantimonide of nickel, crystallizing in the cubic system. Also called ullmannite. CMD nickel bloom 2116

A green hydrated and oxidized patina on rock outcrops indicating the existence of primary nickel minerals; specif. annabergite (a nickel arsenate). The term is also applied to zaratite (a nickel carbonate) and to morenosite (a nickel sulfate). See also: annabergite nickel carbonyl A volatile compound of nickel, Ni(CO)4 , formed by passing carbon monoxide over the heated metal. The compound is decomposed into nickel and carbon monoxide by further heating. It is used on a large scale in industry for the production of nickel from its ores by the Mond process. CTD nickel glance See: gersdorffite nickel green See: annabergite nickeliferous Containing nickel. nickeline a. A hexagonal mineral, 2[NiAs] ; commonly contains antimony, cobalt, iron, and sulfur; one of the chief ores of nickel. Formerly called: niccolite; nickelite; arsenical nickel; copper nickel; kupfernickel. b. The mineral group breithauptite, freboldite, imgreite, langisite, nickeline, sederholmite, sobolevskite, stempflite, and sudburyite. nickel iron a. A mineral, NiFe, containing about 76% nickel and found in meteorites. Isometric. Dana, 4 b. The native alloy of nickel with iron in meteorites. See also: kamacite; taenite. nickelite A former name for nickeline. See also: nickeline nickel ocher An early name for annabergite. Fay nickelous oxide 2117

a. NiO; green, becoming yellow. Found in nature as the mineral bunsenite. Soluble in acids and in ammonium hydroxide; insoluble in water; sp gr, 6.6 to 6.8. NiO absorbs oxygen at 400 degrees C forming Ni2 O3 which is reduced to NiO at 600 degrees C. Used in nickel salts and in porcelain painting. CCD, 2 b. Isometric; green to black; molecular weight, 74.71; melting point, 1,990 degrees C; sp gr, 6.67. Used for painting on china. Bennett; Handbook of Chemistry and Physics, 2 nickel oxide Comprises the two nickel oxides, nickelous oxide (NiO) and nickelic oxide (Ni2 O3 ) , which are used extensively as colorants in glasses, glazes, and enamels. The use of nickel oxide in enamels is generally in the ground coat, in which it is used with cobalt and manganese. It is also used in cover coat enamels to give what is known as a daylight shade for reflector units. Nickelic oxide imparts a color to glass which is dependent upon the character of the alkali present. Nickelous oxide is used in glazes to produce blues, greens, browns, and yellows. Nickel oxide is also one of the principal components of certain type of ferrites, e.g, the nickel-zinc ferrite. See also: nickelous oxide nickel plating The deposition of a coating of metallic nickel by electrolysis. Nelson nickel pyrite See: millerite nickel-skutterudite An isometric mineral, NiAs2-3 ; isostructural with skutterudite; tin white; in intermediatetemperature hydrothermal veins, particularly in association with Co, Ni, Fe arsenides, sulfarsenides, and native silver. Syn: white nickel nickel vitriol See: morenosite nicking a. The cutting of a vertical groove in a seam to liberate coal after it has been holed or undercut. Nelson b. Used in wire-rope terminology to describe the internal crosscutting of wires within a rope. Sinclair, 5 c. The chipping of coal along the rib of an entry or room, which is usually the first indication of a squeeze. Fay d. A vertical cutting or shearing one side of a face of coal. Also called cut; cutting. Fay nickings 2118

Newc. The small coal produced in making a nicking. See also: bug dust; makings. Fay nicol a. Nicol prism. b. Any apparatus that produces polarized light, e.g., Nicol prism or Polaroid. See also: polar; polarizer. nicolite A former name for nickeline. See also: nickeline Nicol prism A special prism for producing polarized light, made from two pieces of Iceland spar (calcite) cemented together with Canada balsam. Light entering the prism is split into two polarized rays; of these, the ordinary ray is totally reflected at the balsam layer while the extraordinary ray is able to pass through the prism. In a petrological microscope two Nicol prisms are incorporated. See also: polarizing prism Niggli's classification a. A classification of igneous rocks on the basis of their chemical composition, similar in some respects to the norm system. It was proposed in 1920 by the Swiss mineralogist Paul Niggli. AGI b. A classification of ore deposits, the major groups being plutonic, or intrusive, and volcanic, or extrusive. It was proposed in 1929. AGI night emerald See: evening emerald night pair Corn. Miners who work underground during the night. The night shift. Fay night shift The coal miners' shift from about 12:00 p.m. to 8:00 a.m. It may be a coal-winning shift, but in general it is a preparation or maintenance shift. Nelson nigritite A product of the coalification of fix bitumens rich in carbon; insoluble or only slightly soluble in organic solvents. It is subdivided into polynigritite, humonigritite, exinonigritite, and keronigritite. Tomkeieff 2119

nil Nothing; zero. Often used in reporting gold and silver assays. Webster 3rd; Fay nine-inch straight A standard 9-in by 4-1/2-in by 2-1/2-in (22.9-cm by 11.4-cm by 6.4-cm) straight brick. nine-point sample Final sample taken for test when a small quantity of finely ground mineral is required for assay. A suitable quantity of dry material is thoroughly mixed on glazed cloth or paper, if necessary, being rolled lightly with a round bottle to break down any floccules. It is then flattened to a disk and eight equal segments are marked out diametrically with a spatula. Approx. equal quantities are taken from each segment and from the center, making the nine points of withdrawal. Pryor, 3 ningyoite An orthorhombic mineral, (U,Ca,Ce)2 (PO4 )2 .1-2H2 O ; rhabdophane group; occurs in an unoxidized zone of the Ningyo-toge Mine, Tottori prefecture, Japan. niobite See: columbite niobium A shiny, white, soft, and ductile metallic element. Symbol, Nb (niobium) or Cb (columbium). The name niobium was adopted by the International Union of Pure and Applied Chemistry. Many chemical societies and government organizations refer to it as niobium, but most metallurgists, metals societies, and commercial producers still refer to the metal as columbium. Found in niobite (or columbite), niobite-tantalite, pyrochlore, and euxenite. Used as an alloying agent in carbon and alloy steels, in nonferrous metals, and in superconductive magnets. Syn: columbium Handbook of Chemistry and Physics, 3 niobium boride One of several compounds that have been reported, including the following: NbB2 ; melting point, 3,050 degrees C; sp gr, 7.0; thermal expansion, 5.9 X 10-6 parallel to a and 8.4 X 10-6 parallel to c; NbB, melting point, 2,300 degrees C; sp gr, 7.6; Nb3 B4 melts incongruently at 2,700 degrees C; sp gr, 7.3. Dodd niobium nitride 2120

One of three nitrides that have been reported: NbN, Nb2 N , and Nb4 N3 . During reaction between niobium and N2 at 800 to 1,500 degrees C the product generally consists of more than one compound. Most of the phases are stable at least to 1,500 degrees C. Dodd nip a. Where the roof and the floor of a coal seam come close together pinching the coal between them. CF: want b. The contact ends of a cable for quick attachment to a power cable. BCI c. The device at the end of the trailing cable of a mining machine used for connecting the trailing cable to the trolley wire and ground. Jones, 1 d. To move a machine along a track by sliding the nip along the trolley wire. Hess e. The seizing of material between the jaws or rolls of a crusher. Nichols, 1 f. See: angle of nip g. To cut grooves at the end of a bar, to make it fit more evenly. h. An undercutting notch in rock, particularly limestone, along a seacoast between high- and low-tide levels produced by erosion or possible solution. AGI niperyth See: penthrite nipple A tubular pipe fitting usually threaded on both ends and under 12 in (30.5 cm) in length. Longer pipe is regarded as cut pipe. See also: close nipple Ni-resist A cast iron consisting of graphite in a matrix of austenite. It contains 3.0% carbon, 14.0% nickel, 6.0% copper, 2.0% chromium, and 1.5% silicon; it has a high resistance to growth, oxidation, and corrosion. CTD nital See: Boylston's reagent niter An orthorhombic mineral, 4[KNO3 ] ; water soluble; has a cooling salty taste; a product of nitrification in most arable soils in hot, dry regions, and in the loose earth forming the floors of some natural caves. CF: nitratine niter cake Crude sodium sulfate, a byproduct in the manufacture of nitric acid from sodium nitrate. Fay 2121

nitrate a. A salt of nitric acid; e.g., silver nitrate or barium nitrate. Standard, 2 b. A mineral compound characterized by a fundamental anionic structure of NO3- . Soda niter, NaNO3 , and niter, KNO3 , are nitrates. CF: carbonate; borate. AGI c. Salts formed by the action of nitric acid on metallic oxides, hydroxides, and carbonates. Readily soluble in water and decompose when heated. The nitrates of polyhydric alcohols and the alkyl radicals explode violently. CTD nitratine A trigonal mineral, NaNO3 ; rhombohedral cleavage; water soluble with a cooling taste; occurs only in very arid regions. Formerly called soda niter. nitrification The formation of nitrates by the oxidation of ammonium salts to nitrites (usually by bacteria) followed by oxidation of nitrites to nitrates. It is one of the processes of soil formation. AGI nitro An abbrev. for nitroglycerin or dynamite. nitrocalcite A monoclinic mineral, Ca(NO3 )2 .4H2 O ; water soluble; soft; occurs as an efflorescence, e.g., on walls and in limestone caves. Syn: wall saltpeter nitrocellulose Nitric acid esters of cellulose formed by the action of a mixture of nitric and sulfuric acids on cellulose. The cellulose can be nitrated to a varying extent, ranging from two to six nitrate groups in the molecule. Nitrocellulose having a low nitrogen content, up to the tetranitrate, is not explosive. They dissolve in ether-alcohol mixtures and in so-called lacquer solvents, such as butyl acetate. A nitrocellulose having a high nitrogen content is guncotton, an explosive. The principal nitrocellulose plastic is celluloid. Syn: cellulose nitrate nitrocotton A chemical combination of ordinary cotton fiber with nitric acid. It is explosive, highly inflammable, and in certain degrees of nitration, soluble in nitroglycerin. nitrogelatin 2122

See: gelatin dynamite nitrogen Colorless, tasteless, odorless, relatively inert element. Symbol, N. Nitrogen makes up 78% of the air, by volume. From this inexhaustible source it can be obtained by liquefaction and fractional distillation. Used in the production of ammonia and nitric acid, as a blanketing medium in the electronics industry, as a refrigerant, in annealing stainless steel, in drugs, and for forcing crude oil from oil wells. Handbook of Chemistry and Physics, 3 nitrogen fixation a. Extracting nitrogen from the air in commercial quantities for use in agriculture or industry. b. In a soil, the conversion of atmospheric nitrogen to a combined form by the metabolic processes of some algae, bacteria, and actinomycetes. AGI nitroglycerin CH2 NO3 CHNO3 CH2 NO3 ; pale yellow; flammable; explosive; thick liquid; soluble in alcohol; soluble in ether in all proportions; slightly soluble in water; melting point, 13.1 degrees C; and explosion point, 256 degrees C. Used as an explosive, in the production of dynamite and other explosives, as an explosive plasticizer in solid rocket propellants, and as a possible liquid rocket propellant. Molecular weight, 227.09; triclinic or orthorhombic when solid; sp gr, 1.5918 (at 25 degrees C, referred to water at 4 degrees C); soluble in methanol and in carbon disulfide; very soluble in chloroform; and slightly soluble in petroleum ether. This highly explosive liquid is made by mixing sulfuric acid and nitric acid in a steel tank and then adding glycerin. Its great shattering effect has made it esp. suitable for shooting oil wells. Because of its sensitiveness to shock, liquid nitroglygerin is dangerous to transport and unsuitable for use in mining and quarrying operations. Syn: glycerol trinitrate; trinitrate glycerol; trinitrin; explosive oil. CCD, 2; Handbook of Chemistry and Physics, 2; Lewis nitroglycerin explosive An explosive containing, principally, nitroglycerin, nitrocotton, and inorganic nitrates, with a suitable combustible absorbent giving a balanced composition. Nelson nitroglycerin powder Explosive usually characterized by a low nitroglycerin content, up to 10% , and a high ammonium nitrate content of 80% to 85%, with carbonaceous material forming the remainder of the composition. This composition produces a powdery consistency and, consequently, nitroglycerin powders have relatively poor water-resistance properties, so that they should be used only in dry conditions. Their storage properties are fairly good, 2123

but this is largely dependent on the protection given after manufacture, for example, in the methods of cartridging and packing. The main application of these explosives is in quarrying and mining where the ground to be blasted is relatively soft. McAdam, 2 nitrohydrochloric acid See: aqua regia nitrolite An excellent and cheap explosive in powder form, consisting of the constituents ammonium nitrate + trotyl + nitroglycerin + silicon. Fraenkel nitromagnesite A monoclinic mineral, Mg(NO3 )2 .6H2 O ; water soluble; white; an efflorescence in limestone caverns. nitromuriatic acid See: aqua regia nitrostarch explosive Nitrostarch explosives have been used to a limited extent for over 50 years. When these explosives were first introduced, nitrostarch was the principal explosive ingredient in their composition. Of recent years, because of the trend toward the low-sensitivity, noncap sensitive nitrocarbonitrates and ammonium nitrate-oil mixtures, certain grades of explosives are being produced with low amounts of sensitizers. Some of these explosives today contain a very large percentage of ammonium nitrate, and nitrostarch is used only in small quantities to act as a sensitizer. Pit and Quarry nitrosubstitution The act or process of introducing by substitution the nitryl radical, NO2 , in place of one or more replaceable hydrogen atoms, such as in an organic compound. Nitrosubstitution compounds are used in the manufacture of some explosives. Standard, 2 nitrosulfuric acid An exceedingly corrosive mixture of one part by weight of nitric acid and two parts by weight of sulfuric acid. Used in the manufacture of nitroglycerin. Standard, 2 nitrous oxide 2124

A gas with the chemical formula, N2 O ; molecular weight, 46; sp gr, 1.6. This gas is produced by the blasting of certain nitroglycerine explosives, esp. if there is incomplete detonation. It is also produced in the exhaust of diesel locomotives. It is used as an anesthetic in dentistry and is commonly known as laughing gas. Morris niveau surface See: equipotential surface noble a. A term used to express great value or purity, as in a noble metal (e.g., platinum); or inertness, as in a noble gas (e.g., helium). See also: noble gas; noble metal. b. An adj. usually modifying "metal" or "gas" and referring to those elements which do not normally combine with oxygen or other non-metallic elements under near-surface conditions; thus they commonly occur as native elements (or alloys). The metals usually included are gold, silver, platinum, palladium, ruthenium, iridium, rhodium, and osmium; the gases are helium, neon, argon, krypton, xenon, and radon. Other elements found in their native states, such as sulfur, copper, or mercury, are not noble because they spontaneously (even though slowly) oxidize. noble gas A rare inert gas: helium, neon, argon, krypton, xenon, and radon. Syn: inert gas nobleite A monoclinic mineral, CaB6 O9 (OH)2 .3H2 O ; tabular or mammillary; transparent; formed by the weathering of colemanite and priceite in Death Valley, CA. noble metal A metal with marked resistance to chemical reaction, particularly to oxidation and to solution by inorganic acids. The list includes mercury and the precious and platinumgroup metals. CF: base metal See also: noble no-cut rounds In blasting underground, drilling all holes straight into the face. Lewis nodular a. Composed of nodules; e.g., nodular bedding consisting of scattered to loosely packed nodules in matrix of like or unlike character. AGI b. Having the shape of a nodule, or 2125

occurring in the form of nodules; e.g., nodular ore such as a colloform mineral aggregate with a bulbed surface. AGI c. Orbicular. AGI nodular cast iron A cast iron that has been treated while molten with a master alloy containing an element, such as magnesium or cerium, to produce primary graphite in the spherulitic form. See also: iron nodular structure See: orbicular structure nodule a. A small, irregularly rounded knot, mass, or lump of a mineral or mineral aggregate, normally having a warty or knobby surface and no internal structure, and usually exhibiting a contrasting composition from the enclosing sediment or rock; e.g., a nodule of pyrite in a coalbed, a chert nodule in limestone, or a phosphatic nodule in marine strata. Nodules can be separated as discrete masses from the host material. AGI b. One of the widely scattered concretionary lumps of manganese, cobalt, iron, and nickel found on the floors of the world's oceans; esp. a manganese nodule. Etymol: Latin nodulus, small knot. CF: concretion AGI c. A rounded material accretion built of successive layers, of easily handled size. Pryor, 3 d. A small, rounded, irregularly shaped mass, as those of graphite in malleable cast iron. Rolfe nodulizing a. The forming of rounded shapes by the application to fine coal of a gyratory, rotary, or oscillatory motion, without the use of pressure. BS, 5 b. See: balling noise a. Any undesired sound. NCB b. By extension, any unwanted disturbance such as undesired electric waves in any transmission channel or device. NCB c. In gravity and magnetic prospecting, disturbances in observed data due to more or less random inhomogeneities in surface and near-surface material. AGI d. In seismic prospecting, all recorded energy not derived from the explosion of the shot. Sometimes loosely used for all recorded energy except events of interest. AGI noise level In observed or recorded data, the fluctuations not attributable to signals. AGI noise reduction rating 2126

A measure of a hearing protector's effectiveness in reducing noise such as results from mining operations where drilling, cutting, blasting, etc. create high noise levels. Abbrev. NRR. MSHA, 2 nolanite A hexagonal mineral, (V,Fe,Ti)10 O14 (OH)2 ; rare; forms tabular prisms and plates; associated with uranium ores at Beaverlodge, SK, Canda, and with native gold and various tellurides at Kalgoorlie, Western Australia. nominal area Of a screen, the total area of the screen deck exposed to the flow of the material feed. BS, 5 nominal bandwidth In a filter, the difference between the nominal upper and lower cutoff frequencies. This difference may be expressed in cycles per second, as a percentage of the pass-band center frequency, or as the difference between the upper and lower cutoffs in octaves. Hy nominal capacity A notional figure expressed in tons per hour used in the title of a flowsheet and in general descriptions of the plant, applying to the plant as a whole and to the specific project under consideration. It may be taken as representing the approximate tonnage expected to be supplied to the plant during the hour of greatest load. BS, 5 nominal price An estimate of the price for a future month date which is used to designate a closing price when no trading has taken place in that date. Also used for current price indications in similar circumstances in physical trading. Wolff nominal screen aperture a. A nominal mesh aperture used to designate the result of a screening operation. BS, 5 b. A notional size at which it is intended to divide a feed by a screening operation. Syn: nominal screen size nominal screen size See: nominal screen aperture nominal size 2127

The limit or limits of particle size used to describe a product of a sizing operation. BS, 5 nomogram A type of line chart that graphically represents an equation of three variables, each of which is represented by a graduated straight line. It is used to avoid lengthy calculations; a straight line connecting values on two of the lines automatically intersects the third line at the required value. Syn: nomograph nomograph See: nomogram nonangular unconformity See: disconformity nonasphaltic pyrobitumen Any of several species of pyrobitumens, including dark-colored, comparatively hard and nonvolatile solids, composed of hydrocarbons containing oxygenated bodies, infusible and largely insoluble in carbon disulfide. This includes peat, coal, and nonasphaltic pyrobitumen shales. Tomkeieff nonbanded coal Coal that does not display a striated or banded appearance on the vertical face. It contains essentially no vitrain and consists of clarain or durain, or of material intermediate between the two. AGI non-Bessemer ore Ore containing up to about 0.18% phosphorus. Newton, 1 noncaking coal Coal that does not form cake; namely hard, splint, cherry, and durain coal. Tomkeieff noncaving method Any of several stoping methods, including open stopes, sublevel, shrinkage, cut-and-fill, and square set. Lewis noncoal mine 2128

A mine in which the material being mined is incombustible or contains at least 65% by weight of incombustible material, and in which the underground atmosphere in any open workings contains less than 0.25% by volume of flammable gas. CFR, 2 noncoking coal A bituminous coal that burns freely without softening or any appearance of incipient fusion. The percentage of volatile matter may be the same as for coking coal, but the residue is not a true coke. Fay noncombustible Any material that will neither ignite nor actively support combustion in air at 1,200 degrees F (649 degrees C) when exposed to fire. See also: incombustible nonconformable Pertaining to the stratigraphic relations shown by a nonconformity. AGI nonconformity a. An unconformity developed between sedimentary rocks and older rocks (plutonic igneous or massive metamorphic rocks) that had been exposed to erosion before the sediments covered them. The restriction of the term to this usage was proposed by Dunbar & Rodgers (1957). Although the term is well known in the classroom, it is not commonly used in practice (Dennis, 1967). AGI b. A term that formerly was widely, but is now less commonly, used as a syn. of angular unconformity, or as a generic term that includes angular unconformity. Term proposed by Pirsson (1915). AGI nonconsumable-electrode arc melting A method of arc melting in which a carbon or tungsten electrode is used and the sponge metal to be melted is fed into the arc at the proper rate. Newton, 1 noncore bit See: plug bit noncore drilling Drilling a borehole without taking core. Long noncoring bit

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A general type of bit made in many shapes that does not produce a core and with which all the rock cut in a borehole is ejected as sludge. Used mostly for blasthole drilling and in the unmineralized zones in a borehole where a core sample is not wanted. Also called blasthole bit; plug bit. CF: fishtail bit; roller bit. Syn: blind bit nondestructive testing Methods of examination, usually for soundness, which do not involve destroying or damaging the material or part being tested. It includes radiological examination, magnetic inspection, etc. Also called nondestructive inspection. Rolfe nondiamond core drill A rotary or percussive-type drill equipped with core-cutting tools or bits, the cutting points of which are not inset with diamonds. Long nonel See: nonelectric blasting nonelectric blasting The firing of one or more charges using safety fuse, igniter cord, detonating cord, shock or gas tubing, or similar nonelectric materials to initiate a blasting cap. Syn: nonel shock tube system. Federal Mine Safety nonelectric delay blasting cap A detonator with an integral delay element and capable of being initiated by miniaturized or regular detonating cord. CFR, 1 nonferrous Of, or relating to, a metal or compound that does not contain appreciable quantities of iron; ores that are not processed primarily for their iron content. nonferrous alloy Specif., an alloy containing no iron. Generically, any alloy that has as its base any element other than iron. Common commercial nonferrous alloys are based upon aluminum, copper, lead, magnesium, nickel, tin, and zinc. Henderson nonferrous metallurgy

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That branch of metallurgy that deals with the broad field of metals other than iron, or alloys other than of iron base. CF: ferrous metallurgy Henderson nonferrous metals a. Classification of metals that are not commonly associated with alloys of iron, including base metals, precious metals, and light metals. b. In singular form, an alloy that has as its base metal a metal other than iron, e.g., copper, lead, aluminum, etc. nonflowing well A well that yields water at the ground surface only by means of a pump or other lifting device. See also: artesian well nonfreezing explosive Explosive to which 15% to 20% of nitroethylene glycol has been added. This acts as a freezing-point depressant and prevents freezing at ordinary temperatures. Polar or Arctic explosives are nitroglycerin explosives of this type. Higham nongraded sediment a. In geology, detrital sediment, loose or cemented, containing notable amounts of more than one grade; e.g., loam or boulder clay. Syn: poorly sorted b. In engineering, sediment in which the constituent particles are all of nearly the same size. Stokes nonhardening salt Salt containing substantial quantities of impurities such as calcium and/or magnesium chloride, which are highly deliquescent and prevent caking. Kaufmann nonluminous flame Hydrogen, carbon monoxide, or aerated coal gas flames. Francis, 2 nonmagnetic rod A drill rod made of brass, aluminum, or other metal unaffected by magnetism. Long nonmagnetic steel Steel alloyed with 12% or more of manganese, chromium, or nickel. Such an alloy cannot be removed from a passing stream of ore by an ordinary guard magnet. Magnetic permeability is below 1.05. Pryor, 3 2131

nonmetal A chemical element (as boron, carbon, phosphorus, nitrogen, oxygen, sulfur, chlorine, or argon) that is not classed as a metal because it does not exhibit most of the typical metallic properties. An element that, in general, is characterized chemically by the ability to form anions, acidic oxides and acids, and stable compounds with hydrogen. Webster 3rd nonmetallic a. Of or pertaining to a nonmetal. AGI b. Said in general of mineral lusters other than metallic luster. CF: submetallic luster c. An industrial mineral; usually used in the plural. AGI nonmetallic armor A tough outer covering or cable sheath of rubber, rubber compound, or thermoplastic, designed to protect cable conductors and insulation from abrasion or other damage from external sources. USBM, 2 nonmetallic mineral a. In resource usage, "nonmetallic mineral" refers to the nonmetallic character of the product, not the mineralogy. Thus graphite is a nonmetallic mineral and molybdenite is "metallic" even though the minerals graphite and molybdenite are so similar in appearance that they may be confused in a casual inspection. Examples include: asbestos, barite, cement, feldspar, gem stones, helium, kyanite, perlite, salt, soda ash, and vermiculite, and even extending to mineral fuels. CF: metallic b. In mineral usage, the luster of a nonopaque mineral, which transmits light at least through the thinnest edges and in thin section. nonmetallic minerals Minerals are conveniently divided into metallic and nonmetallic groups, and then arranged in subdivisions according to the elements which form their main constituents. The nonmetallic minerals (carbon, diamond, coals, bitumen, asphalt, boron, sulfur, rock salt, etc.) lack the properties of the metallic minerals such as a bright metallic luster, hardness, density, and good conduction of heat and electricity. Nelson non-metallic minerals Rocks, minerals, and select naturally occurring and synthetic materials of economic value, exclusive of fuel and metallic ore minerals. The select materials include peat, mineral-derived materials such as lime and cement, and synthetic versions of gemstones, abrasives, graphite, and calcite. Generally, non-metallic minerals undergo no chemical or 2132

mineralogical alteration for and in their end-uses; are low-price, high-volume commodities such as construction materials; are higher-priced and large-volume commodities that are raw materials in the chemical and agricultural industry; and very high price but very low volume materials such as gemstones. A characteristic of nonmetallic minerals is that, in most cases, they maintain their form and physical properties through processing to final end use. See also: industrial minerals AGI; Indust. Miner. non-Newtonian flow Flow in which the relationship of the shear stress to the rate of shear strain is nonlinear; i.e., flow of a subsurface in which viscosity is not constant. AGI nonnitroglycerin explosive Explosive containing TNT instead of nitroglycerin to sensitize ammonium nitrate; a little aluminum powder may also be added to increase power and sensitiveness. Straight TNTammonium nitrate explosives usually contain 15% to 18% TNT and 82% to 85% ammonium nitrate. TNT-ammonium nitrate explosives have densities between 1.0 g/cm3 and 1.2 g/cm3 and velocities of detonation between 3,200 m/s and 4,000 m/s. They are reasonably free from noxious fumes. This type of explosive is susceptible to moisture and should be used only in dry conditions unless packed in sealed containers. The main use of non-nitroglycerin explosives is in primary blasting in quarries and opencast mining, although they are used in some underground work, particularly in ironstone mining. The combination of high strength and relatively high velocity of detonation also makes them applicable for secondary blasting by plaster shooting. McAdam, 2 nonpareil brick An insulating brick. nonpermissible explosive An explosive that is not approved in law for use in gassy mines. nonpolarizable electrode Electrode in which the phenomenon of polarization cannot occur. Schieferdecker nonproductive formation a. A rock unit that, because of its stratigraphic position, is presumed to contain no valuable mineral deposits. Long b. A rock unit in which no minerals of interest are found. Long nonrotating rope 2133

A wire rope composed of 18 strands of 7 wires each; the inner 6 strands are left lay and outer 12 strands are right lay. It is esp. fabricated for use where loads are handled in free suspension, as in lifting of loads with a single line. Lewis nonsegregating chute A chute, usually used to charge stoker hoppers, so designed as to deliver coal in a mixed state rather than having the large lumps tend to be deposited separate from the fine. nonselective mining The object of nonselective mining is to secure a low cost, generally by using a cheap stoping method combined with large-scale operations. This method can be used in deposits where the individual stringers, bands, or lenses of high-grade ore are so numerous and so irregular in occurrence and separated by such thin lenses of waste that a selective method cannot be employed. Nonselective methods of stoping include caving, top slicing, some forms of open stoping, and shrinkage stoping under most conditions. Jackson, 2 nonsequence A diastem or other relatively unimportant sedimentary or stratigraphic interruption. CF: unconformity; paraconformity. nonsignificant anomaly An anomaly that is superficially similar to a significant anomaly but is unrelated to ore. Formerly called false anomaly. Hawkes, 2 nonsparking tool Tool, made from beryllium-copper or aluminum-bronze, that produces no sparks, or low energy sparks, when used to strike other objects. NSC, 1 nonspin cable A wire or fiber cable so constructed as to reduce twisting to a minimum. Long nonspin differential A differential that will turn both axles, even if one offers no resistance. Nichols, 1 nonspinning rope

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A rope wire consisting of 18 strands of 7 wires each, in 2 layers; the inner layer consists of 6 strands lang lay rope and left lay around a small hemp core, and the outer of 12 strands regular lay, right-hand lay. Will carry a load on a single end without untwisting. Hunt nonstranded rope A rope in which the wires are not laid up in strands but in concentric sheaths, and in opposite directions in the different sheaths, which gives the rope nonspinning properties. The outer sheaths are composed of specially shaped interlocking wires, and there is no hemp core in the rope. Sinclair, 5 nonstructural A phase transformation not involving structural rearrangement, e.g., Curie point in magnetism. nontabular deposit A mineral deposit of irregular shape. See also: mass nontectonite Any rock whose fabric shows no influence of movement of adjacent grains; e.g., a rock formed by mechanical settling. Some rocks are transitional between a tectonite and a nontectonite. AGI nontronite A monoclinic mineral, Na0.33 Fe3+2 (Si,Al)4 O10 (OH)2 .nH2 O ; smectite group; expansive, a swelling clay; earthy; occurs in vesicles and veins in weathered basalt and as an alteration product of volcanic glass. Syn: pinguite. Called chloropal; gramenite; morencite. nonuniform flow A flow the velocity of which is undergoing a positive or negative change. If the flow is constant it is referred to as uniform flow. Seelye, 1 nonvitreous A relative term as applied to ceramic products based on the water absorbing characteristics; i.e., brick, tile, etc., which absorb water in excess of that given by the specifications would be described as nonvitreous. See also: impervious; vitreous; semivitreous. 2135

nonvitrified See: nonvitreous nonweathering coal Coal having a weathering index, as defined by U.S. Bureau of Mines standards, of less than 5%. AGI nonwetted a. A term used in the flotation process and applied to certain metallic minerals that are not wetted with water but are easily wetted with oil. Fay b. As used by diamond-bit setters, a diamond inset in a metal or alloy that has not adhered to or wetted the surface of the diamond. Long Norbide Trade name for boron carbide, an artificial abrasive; chemical formula, BC. It is markedly harder than silicon carbide and second only to diamond. AIME, 1 nordite An orthorhombic mineral, (La,Ce)(Sr,Ca)Na2 (Na,Mn)(Zn,Mg)Si6 O17 ; forms pale brown crystals on the Kola Peninsula, Russia. norite A coarse-grained plutonic rock containing basic plagioclase (labradorite) as the chief constituent and differing from gabbro by the presence of orthopyroxene (hypersthene) as the dominant mafic mineral. CF: hypersthenite norm a. The theoretical mineral composition of a rock expressed in terms of normative mineral molecules that have been determined by specific chemical analyses for the purpose of classification and comparison; the theoretical mineral composition that might be expected had all chemical components crystallized under equilibrium conditions according to certain rules. Adj: normative. See also: normative mineral; norm system. CF: mode AGI b. Optimum operating condition of one or more controlled characteristics in a process such as continuous ore treatment. Pryor, 3 normal

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a. Of or pertaining to a solution having a concentration of 1 g-equivalent weight of solute per liter of solution; commonly used term in analytical chemistry. See also: normal solution b. Used to designate aliphatic hydrocarbons, their derivatives, or alkyl radicals, the molecules of which contain a single unbranched chain of carbon atoms. normal air A mixture of dry air and water vapor, varying from 0.1% to 3% by volume (usually over 1% in mines). Hartman, 2 normal arc A term specif. intended to differentiate between the arcs that are commonly observed and the low-pressure skittering arcs. normal calorie The quantity of heat required to raise 1 g of water from 14.5 degrees C to 15.5 degrees C. Newton, 1 normal corrosion When used in connection with galvanic corrosion, it may refer to corrosion of the anodic metal when there is no contact with the dissimilar metal. Schlain normal depth The depth of water in an open conduit that corresponds to uniform velocity for the given flow. It is a hypothetical depth under conditions of steady nonuniform flow, the depth for which the surface and bed are parallel; also termed the neutral depth. Seelye, 1 normal dip See: regional dip normal displacement See: dip slip normal fault A fault in which the hanging wall appears to have moved downward relative to the footwall. The angle of the fault is usually 45 degrees to 90 degrees . There is dip separation, but there may or may not be dip slip. CF: reverse fault; thrust fault. Syn: gravity fault 2137

normal field In magnetic prospecting, the smoothed value of a magnetic field component as derived from a large-scale survey, worldwide or of continental scope. The normal field of the Earth varies slowly with time, and maps of it are as of a certain date. AGI normal fold See: symmetrical fold normal haul A haul whose cost is included in the cost of excavation, so that no separate charge is made for it. Nichols, 1 normalized steel Steel that has been given a normalizing heat treatment intended to bring all of a lot of samples under consideration into the same condition. normalizing conveyor A conveyor that moves material through a normalizing furnace under heat. normally consolidated Said of a soil deposit that has never been subjected to an effective pressure greater than the existing overburden pressure and one that is also completely consolidated by the existing overburden. ASCE normal moisture capacity See: field capacity normal pressure Usually equal to the weight of a column of mercury 760 mm in height. Approx. 14.7 psi (101.4 kPa). Syn: standard pressure Webster 3rd; Fay normal price As applied to metal prices, it is the average over a long term--sometimes a period greater than the life of a mine. See also: basic price normal scale 2138

See: effective temperature normal shift In a fault, the horizontal component of the shift, measured perpendicular to the strike of the fault. See also: offset; shift. AGI normal solution A solution made by dissolving 1 g-equivalent weight of a substance in sufficient distilled water to make 1 L of solution. See also: normal CTD normal stress The stress component at right angles to a given plane. See also: stress ASCE normal stress component That component of the stress in a rock mass that acts perpendicular to the lode plane or any other reference plane. Spalding normal temperature a. Normal temperature and pressure are taken as 0 degrees C (273 degrees absolute) and 30 in (760 mm) of mercury pressure. Also called standard temperature. Cooper b. As applied to laboratory observations of the physical characteristics of bituminous materials, it is 77 degrees F (25 degrees C). Urquhart normal theory A theory claiming that the removal of a coal seam caused the overlying strata to fracture at right angles to the inclination of the beds. Subsidence observations do not support this theory. See also: dome theory normal travel-time curve In fan shooting, a time-distance curve obtained along a profile in some nearby area that does not contain geologic structures of the type being sought. AGI normative The adj. of norm. normative mineral 2139

A mineral whose presence in a rock is theoretically possible on the basis of certain chemical analyses. A normative mineral may or may not be actually present in the rock. See also: norm AGI norm system A system of classification and nomenclature of igneous rocks based on the norm of each rock. It is used in detailed petrologic studies rather than in ordinary geologic or mining work. Syn: CIPW system Norsk-Staal process A process for the direct production of iron sponge. A mixture of carbon monoxide and hydrogen is used as the reducing agent. The equipment consists of three vertical ovens, for preheating, reducing, and cooling the charge, and apparatus for regenerating the spent gases. The ore is contained in a series of muffle trays, each tray holding about 3 tons of ore. These trays pass down through the preheating oven, where the ore is heated to 1,000 degrees C, and are then transferred to the reducing oven, where they are raised through and against the downward gas current, then transferred to the cooling shaft, and slowly lowered down it. The transfer of a tray from one oven to another is made without contact with air. The ore is preheated in the first oven by part of the gases from the reduction oven, and the sponge iron is cooled in the third oven to 50 degrees C by cold gas from a gas holder. Osborne norstrandite A triclinic mineral, Al(OH)3 ; cryptocrystalline; a constituent of strongly weathered soils, of laterites and bauxites. north end York. The rise side of the coal in North Yorkshire. north-seeking pole The end of a magnet that points approx. north. The other end is the south-seeking pole. Morris Norwalt separator Trade name for a dense-medium washer for treating coal lump size down to about 1/8 in (3.2 mm). It comprises a shallow circular tank with a flat base and a conical inner shell containing the driving mechanism. The clean coal floats and passes over a weir while the shale sinks to the bottom and is conveyed to an outlet chute. Its capacity ranges from 2140

about 50 st/h (45.4 t/h) to over 500 st/h (454 t/h), depending on the size of the vessel. Nelson Norwegian cut A variation of the ordinary cut that may be said to represent a combination of the latter and the fan cut. The first drill holes are formed with a sharper angle toward the working face, which facilitates breaking. This type of cut has been employed successfully in headings of small section, the cut hole being blasted first, followed by the bench holes. In order to obtain the maximum possible advance the cut may also be deepened after blasting, during the first pause in working, e.g, the whole section then being broken out simultaneously. Fraenkel nose a. Scot. A point; a projecting angle of coal or other mineral. Also called ness. Fay b. The lead face of the crown of a diamond bit. Long c. A short plunging anticline without closure. d. To dip or run in the form of a geological nose. Webster 3rd nosean An isometric mineral, Na8 Al6 Si6 O24 (SO4 ).H2 O ; sodalite group; occurs in silica- and lime-deficient igneous rocks. Formerly called noselite, nosin, nosite. nose in Eng. A stratum is said to nose in when it dips beneath the ground into a hillside in a Vform or nose form. noselite See: nosean nose out a. Eng. A nose-shaped stratum cropping out. Fay b. To diminish by losing stratum after stratum and getting into the lower part of the measure; said of a coal seam. Standard, 2 nose pipe The inside nozzle of a tuyere. Standard, 2 nosin See: nosean 2141

nosite See: nosean notch a. An angular recess cut in the ends of a crossbar of a timber set to fit over a corresponding wedge in the upright posts. With the advent of steel arches, the craft of notching is becoming extinct. See also: Welsh notch b. Eng. See: let into c. A small weir made for use in measuring flow in laboratory models of hydraulic structures. See also: measuring weir d. A hollow formed by the undermining of a cliff, as a result of wave erosion and/or solution. Schieferdecker notch effect Locally increased stress at that point in a structural load-bearing member where the section changes at a sharp angle. Hammond notcher A machine tool in a steel-fabrication shop used to strip the flanges from the ends of rolled steel joists. Hammond notching a. A method of excavating in a series of steps. Standard, 2 b. Cutting out various shapes from the edge of a strip, blank, or part. ASM, 1 notch sensitivity ratio Alternative term for factor of stress concentration in fatigue or fatigue strength reduction factor. Roark not previously known to exist These words refer to the time of the location and commencement of the tunnel and not to the respective times of the discoveries of the various veins in the tunnel. Ricketts Nottingham system A longwall method of working coal seams in which the trams run on a rail track along the face and are hand loaded at the sides. It follows that the system can be adopted only in relatively thick seams where the trams can travel along the face without any roof ripping. The method is now replaced by face conveyors. Syn: Barry mining 2142

noumeite See: garnierite novackite A monoclinic mineral, (Cu,Ag)21 As10 ; pseudotetragonal; forms steel-gray granular aggregates; at Cerny Dul, Czech Republic. novaculite a. A dense, hard even-textured, light-colored cryptocrystalline siliceous sedimentary rock, similar to chert but characterized by dominance of microcrystalline quartz over chalcedony. It was formerly believed to be the result of primary deposition of silica, but in the type occurrence (Lower Paleozoic of the Ouachita Mountains, Arkansas and Oklahoma) it appears to be a thermally metamorphosed bedded chert, distinguished by characteristic polygonal triple-point texture. The origin of novaculite has also been ascribed to crystallization of opaline skeletal material during diagenesis. The rock is used as a whetstone. See also: Arkansas stone ouachita stone. AGI b. A term used in southern Illinois for an extensive bedded chert. AGI c. A general name formerly used in England for certain argillaceous stones that served as whetstones. AGI nowel a. The inner part of a large mold, corresponding to the core in small work. Standard, 2 b. The bottom or drag of a molding flask, as distinguished from the cope. Standard, 2 noxious gas A gas that is injurious to health. BS, 8 nozzle brick A tabular refractory shape used in a ladle, with a hole through which steel is teemed at the bottom of a ladle, the upper end of the shape serving as a seat for the stopper. ARI nozzleman In metal mining, one who operates a hydraulic giant or monitor (nozzle) used to direct a high-pressure stream of water against a bank of gold-bearing gravel to erode and force the gravel into sluiceboxes, where the gold separates out and is caught by riffles (cleats). Syn: giant tender NPN process 2143

A modification of the basic Bessemer process. The main feature is the shortening of the blow by increasing the pressure of the blast as much as possible. Normally, the melt is cooled by the addition of scrap or iron ore, but it is claimed that a fairly high temperature can be maintained without an undue increase of the nitrogen content, so that ladle skulls can be avoided. Osborne NQ A letter name specifying the dimensions of bits, core barrels, and drill rods in the N-size and Q-group wireline diamond drilling system having a core diameter of 47.6 mm and a hole diameter of 75.7 mm. Cumming, 2 N rod bit A Canadian standard noncoring bit having a set diameter of 2.940 in (74.7 mm). More commonly called a 2-15/16 N drill-rod bit. Long N-truss A bridge or roof truss that has parallel upper and lower chords and an arrangement of web members consisting of tension diagonals and compression verticals, with the vertical struts separating the panels. Also known as a Pratt truss. See also: Warren girder nubber a. Mid. A block of wood about 12 in (30.5 cm) square, for throwing mine cars off the road in case the couplings or ropes break. Fay b. See: stopblocks nuclear-assisted mining The use of a nuclear explosive for fracturing and fragmenting large volumes of ore underground into rubble chimneys, in preparation for block-cave-type mining or in-situ leaching. SME, 1 nuclear log See: radioactivity log nuclear magnetism log Primarily a hydrogen log, useful for the following purposes: (1) provides valuable correlating curve to replace the S.P. in holes containing oil or invert muds; (2) provides a means of qualitatively distinguishing zones containing hydrocarbons from zones containing only water; (3) provides a means of measuring quantitatively what proportion of the total fluid-filled porosity in a formation is sufficiently free from the influence of 2144

chemical binding forces to be considered mobile and thus potentially recoverable; and (4) provides a means of estimating the permeabilities of formations. Wyllie nuclear magnetometer See: nuclear resonance magnetometer nuclear powerplant Any device, machine, or assembly thereof that converts nuclear energy into some form of useful power, such as mechanical or electric power. In a nuclear electric powerplant, heat produced by a reactor is used to make steam, and the steam drives a turbine generator in the conventional way. Lyman nuclear reaction A reaction involving the nucleus of the atom, such as fission, neutron capture, radioactive decay, or fusion; and distinct from a chemical reaction, which is limited to changes in the electron structure surrounding the nucleus. Lyman nuclear resonance magnetometer An instrument that measures the Earth's magnetic field, depending on the magnetic moment of the atom. Hydrogen atoms are generally used, and these can be in a compound such as water. Each hydrogen atom can be viewed as a tiny electromagnet whose strength and direction are determined by the revolution of the electron of the atom about its nucleus. In a magnetic field, atoms of hydrogen have a tendency to align themselves in opposition to the field. If the direction of the field is suddenly changed, there will be a moment pulling the atoms toward the new direction. But each atom is a midget gyroscope, and instead of shifting directly to the new field direction, it will precess about this direction. The frequency of this precession will be a function only of the strength of the magnetic field. Syn: nuclear magnetometer nucleation The beginning of crystal growth at one or more points. AGI nucleometer A Geiger counter employing 20 Geiger tubes to increase the sampling area and overcome the inefficiency of a 1-tube counter. Ballard nucleon A constituent of the atomic nucleus; i.e., a proton or a neutron. Lyman 2145

nucleus The central point about which matter accumulates to form a larger mass, esp. of a growing crystal or pearl. Plural: nuclei. nuclide Any species of atom that exists for a measurable length of time. A nuclide can be distinguished by its atomic weight, atomic number, and energy state. The term is used synonymously with isotope. A radionuclide is the same as a radioactive nuclide, a radioactive isotope, or a radioisotope. Lyman Nuflex Trade name for a nonrotating rope of 17 X 7 or 34 X 7 strand construction. Hammond nugget A large lump of placer gold or other metal. CF: heavy gold nugget effect Anomalously high precious metal assays resulting from the analysis of samples that may not adequately represent the composition of the bulk material tested due to nonuniform distribution of high-grade nuggets in the material to be sampled. SME, 1 nugget model A constant variance model most often used in combination with one or more other functions when fitting mathematical models to experimental variograms. nuisance dust Dust with a long history of little adverse effet on the lungs; does not produce significant organic disease or toxic effect when exposures are kept at reasonable levels. Nujol In flotation, any of a group of nonionizing hydrocarbon oils that act as collector agents by smearing action, giving aerophilic quality to the surface they selectively coat. Pryor, 3 Nullagine Series

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Local name in Western Australia for the formation consisting essentially of preCambrian rocks made up mainly of jasperoid quartzites and dolomite. Crocidolite asbestos occurs in this formation as cross-fiber seams in lodes in stratified ferruginous quartzites and shales with occasional bands of dolomite. Sinclair, 7 nullah a. A term used in the desert regions of India and Pakistan for a sandy river bed or channel, or a small ravine or gully, that is normally dry except after a heavy rain. AGI b. The small, intermittent, generally torrential stream that flows through a nullah. Etymol: Hindi nala. See also: wadi; arroyo. Also spelled: nulla; nallah; nalla. AGI Numidian marble A general name for marbles of cream, yellow, pink, and red color, found in northern Africa. The quarries were worked by the ancient Romans. Nummulite limestone A thick bed of limestone, of Eocene age, composed mainly of the remains of the foraminifer Nummulites. The formation stretches from the Alps through Iran to China. It is the stone of which the Great Pyramid is built. Nusse and Grafer PIV/6 drilling machine A rotary machine used for drilling the holes in combustible gases drainage. It is a twospeed, 150- to 250-rpm machine, drill-rod rotation being operated by a 6-hp (4.47-kW) motor. Traversing is done by a 2-hp (1.5-kW) motor, a pinion of which engages a toothed rack that runs the length of the drill frame. A forward drilling thrust of 4 st (3.6 t) is possible. The machine measures 10 ft (3 m) overall and weighs about 1,000 lb (454 kg). With an improved high-speed gearbox, 100 to 130 ft (30 to 40 m) of coal measures strata can be drilled in a shift. Nelson nut coal a. An abbrev. for chestnut coal. Also called nuts. Fay b. Prepared bituminous coal that passes through 2- to 3-in (5.1- to 7.6-cm) round holes and over 3/4-, 1-, or 1¬-in (1.9-, 2.54-, or 3.2-cm) holes, depending on the screening practice. Anthracite, through 1-5/8in (4.1-cm) and over 3/16-in (4.8-mm) round holes. Jones, 1 nutcracker See: boulder buster NW 2147

Letter name specifying the dimensions of bits, core barrels, and drill rods in the N-size and W-group wireline diamond drilling system having a core diameter of 54.7 mm and a hole diameter of 75.7 mm. The NW designation has replaced the NX designation. Cumming, 2 NX The NX designation for coring bits has been replaced by the NW designation. See also: NW nylon A generic term for a group of synthetic fiber-forming polyamides. The polymer is melted, extruded, stretched, and finally processed to turn it into a textile yarn having a very high strength, great powers of energy absorption, and high resistance to abrasion and rotting. Its major uses in mining are as a reinforcement for conveyor belting and ventilation ducting. Nelson nylon belt A rubber belt containing nylon fiber reinforcing. It is stronger than cotton-duck belts of equivalent size and possesses better troughability and fastener holding strength. Nylon belt has the advantage of a long flex life, and the thinner carcass means easier bending. Nelson nystagmus An eye disease suffered by some miners, in which there is a spasmodic oscillatory movement of the eyeballs; in severe cases, the victim finds difficulty in walking straight. Bad lighting is generally believed to be the main cause, and is possibly aggravated by the workers lying on their sides in thin seams. See also: mining disease

O oakum Loosely twisted fiber usually of hemp or jute impregnated with tar or with a tar derivative (such as creosote or asphalt); used in caulking seams (such as the wood hulls and decks of ships) and in packing joints (in pipes, caissons, etc.). Webster 3rd Oamaru stone

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A white, granular limestone found in large quantities in Oamaru, New Zealand, and valued as a building stone. obduction The overriding or overthrusting of oceanic crust onto the leading edges of continental lithospheric plates; plate accretion. See also: subduction AGI object glass See: objective objective The lens (or lenses) that gives an image of an object in the focal plane of a microscope or telescope eyepiece. Syn: objective lens; object glass. objective glass See: objective objective lens See: objective oblique block A quarry term applied to a block of stone bounded by 3 pairs of parallel faces--4 of the 12 interfacial angles being right angles, 4 obtuse, and 4 acute. oblique fault A fault that strikes oblique to, rather than parallel or perpendicular to, the strike of the constituent rocks or dominant structure. CF: oblique-slip fault; strike fault; dip fault. Syn: diagonal fault AGI oblique illumination method See: van der Kolk method oblique joint a. A joint whose strike is oblique to the strike of the strata or metamorphic rocks in which it occurs. b. A joint that forms an acute angle with dip joints and strike joints. Lewis 2149

oblique offset The distance of a point from a main survey line measured at an angle to the latter that is not a right angle. See also: offset oblique projection A pictorial view of an object showing its elevation, plan, or section to scale with parallel lines projected from the corners, at 45 degrees or any other angle, indicating the other sides. See also: axonometric projection; isometric projection. Hammond oblique slip In a fault, movement or slip that is intermediate in orientation between the dip slip and the strike slip. CF: strike slip oblique-slip fault A fault in which the net slip lies between the direction of dip and the direction of strike. Syn: diagonal-slip fault obra The narrow prismatic part of a blast furnace immediately above the crucible. Fay obsequent fault-line scarp A scarp along a fault line, where the topographically low area is on the upthrown block. CF: resequent fault-line scarp observer a. In seismic prospecting, the person in charge of the recording crew, including the shooters and linemen. The observer must maintain the electronic equipment and decide on the best shooting and detector arrangement as well as the best instrumental settings for getting records of optimum quality. The observer operates the recording equipment in the field, often with the help of an assistant. In conventional recording, or in tape recording when photographic monitors are run, the observer or an assistant develops the record in the recording truck immediately after it is shot. Also called operator. Dobrin b. In gravity and magnetic prospecting, a person who secures the instrument readings, e.g., on a torsion balance or magnetometer. AGI obsidian

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A black or dark-colored volcanic glass, usually of rhyolite composition, characterized by conchoidal fracture. It is sometimes banded or has microlites. Usage of the term goes back as far as Pliny, who described the rock from Ethiopia. Obsidian has been used for making arrowheads, other sharp implements, jewelry, and art objects. Syn: Iceland agate AGI obsidianite brick Lightweight, siliceous fireclay, acid-resisting brick, burned to a glasslike mass. obtuse bisectrix a. That axis that bisects the obtuse angle of the optic axes of biaxial minerals. Fay b. The angle >90 degrees between the optic axes in a biaxial crystal, bxo. CF: optic angle occidental cat's-eye See: cat's-eye; tiger's-eye. occlude To take in and retain (a substance) in the interior rather than on an external surface; to sorb. Used esp. of metals sorbing gases; e.g., palladium occludes large volumes of hydrogen. Webster 3rd occluded Contained in pores (said of gas occluded in coal). Mason occluded gas Any of several gases that enter a mine atmosphere from pores, as feeders and blowers, and also from blasting operations. These gases pollute the mine air chiefly by the absorption of oxygen by the coal, and in addition by chemical combination of oxygen with carbonaceous matter, for example, from decaying timbers, rusting of iron rails, burning of lights, and breathing of humans and animals. These gases include oxygen, nitrogen, carbon dioxide, and methane. Kentucky occlusion a. Taking up or incorporation of liquids in solids or of gases in liquids. AGI b. See: absorption occupant 2151

An occupant of a tract of land, as the word ordinarily is used, is one who has the use and possession thereof, whether he resides upon it or not. Ricketts occupation As used in the mining law, it is equivalent to possession, and the right to locate is included in the right to occupy, and incident to a location is the right of possession; but mere occupancy of the public lands and making improvement thereon gives no vested right therein as against a location made in pursuance of law. Ricketts occurrence See: mineral occurrence ocean current a. The name current is usually restricted to the faster movements of the ocean, while those movements that amount to only a few miles a day are termed drifts. AGI b. A nontidal current constituting a part of the great oceanic circulation. Examples are gulf stream, kuroshio, and equatorial currents. AGI oceanic ridge See: Mid-Atlantic Ridge; mid-ocean ridge. oceanic trench See: trench oceanographic dredge Apparatus used aboard ships to bring up quantity samples of the ocean bottom deposits and sediments. Hunt oceanography The broad field of science that includes all fields of study that pertain to the sea. This includes the studies of boundaries of the ocean, its bottom topography, the physics and chemistry of seawater, the characteristics of its motion, and marine biology. Hy ocher A name given to various native earthy materials used as pigments. They consist essentially of hydrated ferric oxide admixed with clay and sand in varying amounts and in impalpable subdivision. When carrying much manganese ochers grade into umbers. 2152

They are either yellow, brown, or red. The best reds are sometimes obtained by calcining the yellow varieties. They are called burnt ochers. Others are obtained by calcining copperas or as a residue from roasting pyrite. In general, the native yellows and browns are varieties of limonite and the native reds are varieties of hematite. One variety of red ocher is known as scarlet ocher. Their value as pigments depends not only on the depth of color but also on the amount of oil required as a vehicle. Syn: terra sienna CCD, 2 octagon A polygon having eight sides. Jones, 2 octahedral borax A rhombohedral form of hydrous sodium borate, Na2 B4 O7 .5H2 O , simulating regular octahedrons. From the Lagoong of Tuscany, Italy. See also: tincalconite octahedral cleavage In the isometric system, cleavage parallel to the faces of an octahedron. Fay octahedral copper See: cuprite octahedral iron ore See: magnetite octahedrite a. A class of meteorites. Hey, 1 b. The most common iron meteorite contains 6% to 18% nickel in the metal phase; on etching, shows Widmanstaetten structure owing to the presence of intimate intergrowths (of plates of kamacite with narrow selvages of taenite) oriented parallel to the octahedral planes. c. A former name for anatase. See also: titanium dioxide octahedron a. A closed crystallographic form with isometric symmetry and eight faces, each an equilateral triangle; sometimes called a regular octahedron to distinguish it from the more general usage defined below. Commonly observed in isometric minerals, such as fluorite, pyrite, magnetite, and diamond. b. Less precisely, a closed crystallographic form composed of (or bounded by) eight triangular surfaces (a bipyramid), such as in some samples of anatase. Plural: octahedra. Adj.: octahedral. 2153

octant Each eighth of crystal space divided by three noncoplanar axial planes. CF: dodecant octant search Used to limit the number of sample data points used for estimating intermediate spatial values. The search neighborhood is divided into eight equal-angle sectors. Constraints on selection of data values to include in the estimation include: minimum and maximum of samples or the number of consecutive empty sectors. If either criteria is below minimum, an interpolated value is not calculated. Applies to any interpolation method where a limited number of sample data points are used to estimate intermediate values. octaphyllite a. A trioctahedral clay mineral. AGI b. A group of mica minerals that contains eight cations per ten oxygen and two hydroxyl ions. c. Any mineral of the octaphyllite group, such as biotite; a trioctahedral clay mineral. CF: heptaphyllite octopus A bin or tank to facilitate the concrete lining of circular shafts. The concrete is mixed on the surface, taken down the shaft in buckets, and discharged into the octopus. The concrete is then led away through flexible rubber pipes to different points around the shaft. Nelson ocular Eyepiece of a microscope. Pryor, 3 O'Donaghue formula A formula used for calculating the thickness of tubbing: t = hdF/2C + A, where: t is the required thickness of tubbing in inches; h is the pressure of water in pounds per square inch; d is the diameter of the shaft in inches; C is the crushing strength of cast iron in pounds per square inch, which may be taken as 95,000; F is the factor of safety adopted between 5 and 10; and A is the allowance for possible flaws and corrosion and may vary from 1/4 to 1 in (6.4 to 25.4 mm), averaging 1/2 in (12.7 mm). Sinclair, 2 O'Donahue's theory A mine subsidence theory based on an extension of the theory of the normal. In it, subsidence is regarded as taking place in two stages. There is, first, a breaking of the rocks in which the lines of fracture tend to run at right angles to the stratification. This is 2154

followed by an aftersliding, or inward movement from the sides, resulting in a pull or draw beyond the edges of the workings. Briggs odontolite A fossil bone or tooth colored deep blue by iron phosphate (vivianite), and rarely green by copper compounds, and resembling turquoise, such as that from the tusks of mammoths found in Siberia. It is cut and polished for jewelry. Syn: bone turquoise; fossil turquoise. AGI oersted a. The practical, cgs electromagnetic unit of magnetic intensity. A unit magnetic pole, placed in a vacuum in which the magnetic intensity is 1 Oe (79.577 A/m), is acted upon by a force of 1 dyn in the direction of the intensity vector. AGI b. Commonly used as the cgs unit of magnetic-field intensity. Except in magnetized media, a magnetic field with an intensity (H) of 1 Oe has an induction (B) of 1 Gs (0.1 mT). AGI Oetling freezing method A method of shaft sinking by freezing wet ground in sections as the sinking proceeds. The permanent lining is also inserted as the shaft is sunk. The freezing equipment is a cylinder equal in diameter to the shaft and 44 in. (1.12 m) in height, with the lower end closed by a plate. The cylinder is in sections, each of which can be removed. Each section is provided with freezing coils. After freezing the ground, two sections are removed, the ground is thawed locally and removed, and a segment of the permanent lining is inserted. The process is repeated. See also: Dehottay process; freezing method. Nelson offcenter waterway A waterway port in a noncoring diamond bit, not located in the center of the bit face. Long off gate N. of Eng. One of the goaf roadways in longwall workings, which are set about 120 yd (110 m) apart. Fay off-highway truck A truck of such size, weight, or dimensions that it cannot be used on public highways. official plat of survey 2155

The expression in a patent according to the official plat of survey of the land returned to the general land office by the surveyor general refers to the description of the land as well as to the quantity conveyed. Ricketts off line a. A condition existing when the drive rod of the drill swivel head is not centered and parallel with the borehole being drilled. Long b. A borehole that has deviated from its intended course. Long c. A condition existing wherein any linear excavation (shaft, drift, borehole, etc.) deviates from a previously determined or intended survey line or course. off-peak load Electricity drawn at a period when the power station that supplies it is not fully loaded. Pryor, 3 offretite A hexagonal mineral, (K2 ,Ca)5 Al10 Si26 O72 .30H2 O ; zeolite group; commonly intergrown with erionite and levyne as a vein or cavity filling in mafic lavas. offset a. A short drift or crosscut driven from a main gangway or level. Fay b. The horizontal distance between the outcrops of a dislocated bed. Fay c. Of a fault, the horizontal component of displacement, measured perpendicular to the disrupted horizon. See also: normal shift AGI d. A side (horizontal) measurement of distance perpendicular to a line, usually a transit line. Seelye, 2 e. To collar and drill a borehole at some distance from the designated site to avoid a difficult setup. Long f. To drill a borehole near one previously drilled, which may have been lost, for purposes of correlation or to determine the lateral extent of mineralization. Long g. An abrupt change in the trend of a drill hole, usually caused by a small shelflike projection of rock alongside one wall of the drill hole. Long h. A well drilled near the boundary of a lease opposite a completed well on an adjacent lease. Syn: offset hole; offset well. Long i. To offset a well by drilling the next adjoining location in accordance with a spacing pattern. Wheeler, R.R. j. A spur or minor branch from a principal range of hills or mountains. k. The distance along the strain coordinate between the initial portion of a stress-strain curve and a parallel line that intersects the stress-strain curve at a value of stress which is used as a measure of the yield strength. It is used for materials that have no obvious yield point. A value of 0.2% is commonly used. ASM, 1 offset deposit a. A mineral deposit, esp. of sulfides, formed partly by magmatic segregation and partly by hydrothermal solution, near the source rock. AGI b. At Sudbury, ON, Canada, the 2156

term refers to dikelike bodies radiating from the Sudbury Complex, thought to have been filled from above by xenolithic rock fragments and massive pyrrhotite-chalcopyritepentlandite. AGI offset digging In a ladder ditcher, digging with the boom not centered in the machine. Nichols, 1 offset hole See: offset offset line In surveying, a line established parallel to the main survey line, and usually not far from it; e.g., a line on a sidewalk, 2 ft (0.6 m) from the established street line, or a line parallel to the centerline of a bridge and 50 ft (15.2 m) from it. Seelye, 2 offset ridge A ridge that is discontinuous because of faulting. AGI offset staff In surveying, a rod, usually 10 links (0.2012 m) long, used in measuring short offsets. Webster 2nd offset well See: offset off-sider A driller or drill-crew-worker working on the opposite shift. Also called drill helper. Long offtake A length of boring rods unscrewed and detached at the top of a borehole. Also called rod stand; setout. BS, 9 offtake lad See: shackler 2157

offtake rod One of the auxiliary rods at the top of a winding shaft for guiding and steadying the cages during decking or loading and unloading operations. Nelson off-the-road hauling Hauling that takes place off the public highways, generally on a mining or excavation site. The hauling units used are generally higher and wider than those used in over-theroad hauling since highway restrictions do not limit size, weight, etc. CF: over-the-road hauling off the solid In this type of blasting, coal is blasted from the solid with no precutting or shearing. McAdam, 2 ogie The space before the fire in a kiln. Also called killogie. Standard, 1 ohm The practical mks unit of electric resistance that equals the resistance of a circuit in which a potential difference of 1 V produces a current of 1 A; the resistance in which 1 W of power is dissipated when 1 A flows through it. The standard in the United States. Symbols, Omega and omega . Webster 3rd; Zimmerman ohmmeter A type of galvanometer that directly indicates the number of ohms of the resistance being measured. Crispin Ohm's law The formula expressing Ohm's law is I = E/R, in which I is the electric current in amperes; E is the electromotive force in volts; and R is the resistance in ohms. Handbook of Chemistry and Physics, 2 -oid A suffix meaning "in the form of." AGI oikocryst 2158

In poikilitic fabric, the enclosing crystal. AGI oil agglomeration A coal beneficiation process in which an oil is used to preferentially wet the coal particles, which have an affinity to agglomerate into masses that are then selectively removed by screening, e.g. See also: selective agglomeration oil base The residuum from the distillation of petroleum. When paraffin is obtained from petroleum, the original oil is said to have a paraffin base; when the residue is entirely asphaltic, the original petroleum is said to have an asphaltic base. Some petroleums have both an asphaltic and a paraffin base. API, 1 oil-bearing shale Shale impregnated with petroleum. Not to be confused with oil shale. Tomkeieff oiled A term used in flotation when a particle is given a water repellent surface. When such a coating has been formed, the particle is said to be oiled or treated and ready to be floated. Newton, 1 oiler a. In flotation, oil that provides a film around a mineral particle. b. One of several types of mechanical devices that deliver oil to machines and into air or steam lines in controllable amounts. Also called atomizer; line oiler; lubricator; oil pot; pineapple; pot. Long oilfield winch An extremely powerful low-speed winch on a crawler tractor. Nichols, 1 oil flotation A process in which oil is used in ore concentration by flotation. Syn: flotation process oil of vitriol Concentrated sulfuric acid. oil pot 2159

See: line oiler; oiler. oil pump A hydraulic pump supplying oil under pressure to the hydraulic-feed cylinders and pistons of a hydraulic-type swivel head on a diamond drill. Long oil shale A kerogen-bearing, finely laminated brown or black sedimentary rock that will yield liquid or gaseous hydrocarbons on distillation. CF: bituminous shale petrolo-shale. AGI oilstone A fine-grained stone used for sharpening edged tools or other similar metal surfaces. Fay oil-temper To harden steel by quenching in oil after heating. Webster 3rd okenite A triclinic mineral, Ca10 Si18 O46 .18H2 O ; white; fibrous; commonly associated with zeolites in basalts. old age a. The stage in the development of a stream at which erosion is decreasing in vigor and efficiency, and aggradation becomes dominant as the gradient is reduced. It is characterized by a broad open valley with a flood plain that may be 15 times the width of the meander belt; numerous oxbows, bayous, and swamps; a sluggish current; and slow erosion, effected chiefly by mass-wasting at valley sides. AGI b. The final stage of the cycle of erosion of a landscape or region, in which the surface has been reduced almost to base level and the landforms are marked by simplicity of form and subdued relief. It is characterized by a few large meandering streams flowing sluggishly across broad flood plains, separated by faintly swelling hills, and having dendritic distributaries; and by peneplanation. AGI c. A hypothetical stage in the development of a coast, characterized by a wide wave-cut platform, a faintly sloping sea cliff pushed far inland, and a coastal region approaching peneplanation. The stage is probably a theoretical abstraction, since it is doubtful whether stability of sea level is maintained long enough for the land to be so reduced. AGI oldhamite

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An isometric mineral, (Ca,Mn)S ; pale brown; occurs in some meteorites and slags; rapidly oxidizes in contact with air. Oldham stone duster A self-contained transportable stone duster. A high-velocity current of air from a fan or blower is mechanically fed from a hopper above, both the fan and the feeding mechanism being driven from the tub axle as it is drawn along by rope haulage, horse, or manually. It delivers about 3/4 lb (0.34 kg) of dust per yard (0.9 m) of travel. Sinclair, 1 Oldham-Wheat lamp A cap lamp designed for full self-service. This lamp, weighing 6-5/8 lb (3.0 kg), has a 4V lead-acid battery in a hard rubber case with covers of stainless steel or nickel-plated hard brass. The switch is magnetically operated and is situated in a sealed plastic moulding. A 4-W bulb burning 11 h or a 2-W bulb burning 14 h is used. The lamp is of one-piece construction and no dismantling is needed to charge the accumulator. Sinclair, 1 old hole See: main hole oldland a. Any ancient land; specif. an extensive area (such as the Canadian shield) of ancient crystalline rocks reduced to low relief by long-continued erosion and from which the materials of later sedimentary deposits were derived. AGI b. A region of older land, behind a coastal plain, that supplied the material of which the coastal-plain strata were formed. AGI c. A term proposed by Maxson and Anderson (1935) for the land surface of the old-age stage of the cycle of erosion, characterized by subdued relief. AGI Old Red Sandstone A thick sequence of nonmarine, predominantly red sedimentary rocks, chiefly sandstones, conglomerates, and shales, representing the Devonian System in parts of Great Britain and elsewhere in northwestern Europe. AGI old scrap Scrap derived from consumer goods that have outlived their usefulness in the economy; it includes discarded white goods, automobiles, electrical equipment, machinery, etc. old silver 2161

Silver made to appear old by the application of graphite and grease. old waste Scot. Old or abandoned workings. Fay old working Mine working that has been abandoned, allowed to collapse, and perhaps sealed off. Unless proper safeguards are taken, old workings can be a source of danger to workings in production particularly if they are waterlogged and their plan position is uncertain. See also: inrush of water oleander-leaf texture Leaf-shaped masses of stromeyerite (or other minerals) in a matrix of chalcocite (or other mineral). AGI oleic acid Ch3 (CH2 ),CH:CH(CH2 )7 COOH ; a mono-unsaturated fatty acid used in ore flotation; insoluble in water; and soluble in alcohol, ether, and in most other organic solvents. CCD, 2 oligist See: hematite oligist iron See: hematite Oligocene An epoch of the early Tertiary Period, after the Eocene and before the Miocene; also, the corresponding worldwide series of rocks. It is considered to be a period when the Tertiary is designated as an era. AGI oligoclase A triclinic mineral, (Na,Ca)[(Si,Al)AlSi2 O8 ] ; plagioclase series of the feldspar group; has NaSi (albite) 10 to 30 mol % and CaAl (anorthite) 90 to 70 mol %; pseudomonoclinic with prismatic cleavage and characteristic polysynthetic twinning commonly visible on cleavage traces; white; may be chatoyant; a common rock-forming 2162

mineral in igneous and metamorphic rocks of intermediate to high silica content; forms the entire mass in some anorthosites; less commonly a vein mineral. oligonite A former name for manganoan siderite, (Fe,Mn)CO3 . oligosiderite A meteorite containing a small amount of metallic iron. AGI oligotrophic peat Peat poorly supplied with nutrients. Tomkeieff olivenite An orthorhombic mineral, Cu2 AsO4 (OH) ; adamantine to vitreous; a secondary mineral in copper deposits. Oliver filter A continuous-type filter made in the form of a cylindrical drum with filter cloth stretched over the convex surface of the drum. The drum rotates slowly about a horizontal axis, and the lower part is immersed in a tank containing the pulp to be filtered. Arrangement of pressure and suction pipes on the interior of the drum permits the application of suction to the filtering surface. As the filter passes through the tank, it picks up a layer of solid material and emerges carrying a layer of filter cake. Syn: continuous filter olivine A mineral group including fayalite, Fe2 SiO4 ; forsterite, Mg2 SiO4 ; liebenbergite, (Ni,Mg)2 SiO4 ; and tephroite, Mn2 SiO4 ; orthorhombic; olive green, grayish green, brown, or black; members intermediate in the forsterite-fayalite crystal solution series are common rock-forming minerals in gabbros, basalts, peridotites, and dunites; alters hydrothermally to serpentine. Fayalite occurs in some granites and syenites, forsterite in thermally metamorphosed dolomites, and tephroite in iron manganese ore deposits and their associated skarns. Syn: peridot; chrysolite; olivinoid. olivine rock See: dunite olivinite 2163

a. In the International Union of Geological Sciences classification, Syn: dunite b. An olivine-rich ore-bearing igneous rock that also contains other pyroxenes and/or amphiboles. Syn: leucochalcite olivinoid An olivinelike substance found in meteorites. See also: olivine Standard, 2 olivinophyre Porphyry containing olivine phenocrysts. Fay ollenite A type of hornblende schist characterized by abundant epidote, sphene, and rutile. Garnet is one of the accessories. AGI O.L.P. steel process A steelmaking method similar to the L.D. except that powdered lime is blown with the oxygen stream (therefore, the letters O.L.P.--oxygen- lime-powder). See also: L Nelson ombrogenous peat Peat, the nature of which is determined by the amount of rainfall. Tomkeieff omnibus In glassmaking, a sheet-iron cover to protect, from drafts, the glass articles in a leer. Standard, 2 omnidirectional hydrophone A hydrophone whose response is essentially independent of angle of arrival of the incident sound wave. Hy omphacite A mineral of the pyroxene group intermediate among aegirine, jadeite, and augite; i.e., high in aluminum and sodium, and of high-pressure origin; monoclinic; pale to grass green; occurs in eclogites. o.m.s.

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a. Output (usually in hundredweights) per manshift. It is a method of expressing the productivity of mines, miners, and management. Nelson b. N. of England. Output (usually tons) per manshift. Interpretation depends on the basis for calculating manshifts, e.g., face o.m.s. is based on manshifts at the face; seam o.m.s. on piecework and bargain work manshifts in the seam; overall (pit) o.m.s. on all manshifts underground, including datal labor. Trist on air a. The state of a pump which is operating although having no liquid in its working parts. BS, 10 b. Scot. Said of a pump when air is drawn at each stroke. oncosimeter An instrument for determining the specific gravity of a molten metal by the immersion of a ball made of another metal and of known weight. Standard, 2 onegite A variety of goethite. Hey, 1 one on two A slope in which the elevation rises 1 ft (m) in 2 horizontal ft (m). Nichols, 1 one-part line A single strand of rope or cable. Nichols, 1 one-piece set A term applied to a single stick of timber, called a post, stull, or prop. Post and prop are applied to vertical timbers, and stull is applied to inclined timbers, or those placed horizontally. See also: set Lewis one shot a. A borehole-survey instrument that records a single inclination and/or bearing reading on each round trip into a borehole. Long b. Single shot. one-shot exploder See: Little Demon exploder one-spot strip mining 2165

Consists of three operations: the top material is cast out of the way; pay material is dug and trucked away; and the top is pushed or cast back in. Nichols, 1 one-way ram A hydraulic cylinder in which fluid is supplied to one end so that the piston can be moved only one way by power. Syn: single-acting ram Nichols, 1 one-way ventilation See: peripheral ventilation onion-skin weathering See: spheroidal weathering onlap a. An overlap characterized by the regular and progressive pinching out, toward the margins or shores of a depositional basin, of the sedimentary units within a conformable sequence of rocks, in which the boundary of each unit is transgressed by the next overlying unit and each unit in turn terminates farther from the point of reference. Also, the successive extension in the lateral extent of strata (as seen in an upward sequence) due to their being deposited in an advancing sea or on the margin of a subsiding landmass. Ant: offlap. Syn: transgressive overlap CF: overlap b. The progressive submergence of land by an advancing sea. CF: transgression on line a. A linear underground excavation advancing in compliance with a predetermined surveyed direction or line. b. A borehole the course of which is not deviating from the intended direction. Long c. Said of a diamond drill when its drive rod is centered on and parallel to a borehole. Long on long awn A face between end and crosscut. Sinclair, 6 onofrite A former name for selenian metacinnabar Hg(S,Se) . on plane

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Scot. In a direction at right angles to, or facing, the plane or main joints. Syn: plane course onsetter a. The person in charge of loading and unloading of cages or skips at the pit bottom, and also the signaling to the pithead. In modern mines, the onsetter is stationed in a cabin and all controls are within reach for the loading and unloading of the cages, shaft signaling, and other car control equipment at the shaft bottom. See also: cager; hitcher. Nelson b. The person in charge of winding operations underground, who is stationed at the shaft side and gives all signals to the winding engineman. Mason onsetting machine Eng. A mechanical apparatus for loading cages with full tubs and discharging the empties, or vice versa, at one operation. Fay on short awn A face in a direction between bord and crosscut. Sinclair, 6 on sights a. Following sights placed by a surveyor. Fay b. On line. Ontarian a. Stage in New York State: Middle Silurian (middle and lower parts of Clinton Group). AGI b. An obsolete name for the Middle and Upper Ordovician in New York State. AGI on-the-solid a. Applied to a blasthole extending into coal farther than the coal can be broken by the blast. Fay b. That part of a blasthole that cannot be broken by the blast. Fay c. A practice of blasting coal with heavy charges of explosives, in lieu of undercutting or channeling. Fay on the track Diamonds inset in the crown of a bit in concentric circles so that the diamonds in any one circle follow the same groove cut into the rock. Long onyx

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a. A chalcedonic variety of quartz with color, chiefly white, yellow, red, or black, in straight parallel bands; used esp. in making cameos. See also: banded agate; agate; chalcedony; sardonyx; jasponyx. CF: onyx agate b. A name applied incorrectly to dyed, unbanded, solid-color chalcedony; esp. black onyx. c. Adj. Parallel banded; e.g., onyx marble and onyx obsidian. d. Jet black translucent layers of calcite from cave deposits, often called Mexican onyx or onyx marble. See also: travertine onyx agate Banded agate with straight parallel layers of differing tones of gray; not a syn. for onyx. CF: onyx onyx marble Translucent, generally layered, cryptocrystalline calcite with colors in pastel shades, particularly yellow, brown, and green. See also: cave onyx; Egyptian alabaster; oriental alabaster; Mexican onyx; travertine. ASTM oolite a. A sedimentary rock, usually a limestone, made up chiefly of ooliths cemented together. The rock was originally termed "oolith." Syn: roestone; eggstone. AGI b. A term often used for oolith, or one of the ovoid particles of an oolite. Etymol. Greek oon, egg. CF: pisolite oolith One of the small round or ovate accretionary bodies in a sedimentary rock, resembling the roe of fish, and having diameters of 0.25 to 2 mm (commonly 0.5 to 1 mm). It is usually formed of calcium carbonate, but may be of dolomite, silica, or other minerals, in successive concentric layers, commonly around a nucleus such as a shell fragment, an algal pellet, or a quartz-sand grain, in shallow, wave-agitated water; it often shows an internal radiating fibrous structure indicating outward growth or enlargement at the site of deposition. CF: pisolith ovulite. AGI oolitic Pertaining to an oolite, or to a rock or mineral made up of ooliths; e.g., an oolitic ironstone, in which iron oxide or iron carbonate has replaced the calcium carbonate of an oolitic limestone. AGI oolitic limestone

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An even-textured limestone composed almost wholly of relatively uniform calcareous ooliths, with virtually no interstitial material. It is locally an important oil reservoir (such as the Smackover Formation in Arkansas), and is also quarried for building stone. AGI oolitic texture The texture of a sedimentary rock consisting largely of ooliths showing tangential contacts with one another. AGI ooze a. A soft, slimy, sticky mud. Fay b. To emit or give out slowly. Webster 3rd c. A finegrained pelagic deposit that contains more than 30% of material of organic origin. AGI d. An unconsolidated deposit composed almost entirely of the shells and undissolved remains of foraminifera, diatoms, and other marine life; diatom ooze and foraminiferal ooze. Hy opacite A general term applied to swarms of opaque, microscopic grains in rocks, esp. as rims that develop mainly on biotite and hornblende phenocrysts in volcanic rocks, apparently as a result of post-eruption oxidation and dehydration. Opacite is generally supposed to consist chiefly of magnetite dust. CF: ferrite opacity The quality of being opaque. See also: opaque opal An amorphous or microcrystalline mineral, SiO2 .nH2 O ; may be tridymite or cristobalite; has a varying proportion of water (as much as 20% but commonly 3% to 9%); occurs in nearly all colors; transparent to nearly opaque; typically shows a marked iridescent "play of color"; differs from quartz in being isotropic; has a lower refractive index than quartz and is softer, more soluble, and less dense; generally occurs massive and may be pseudomorphous after other minerals; deposited at low temperatures from silica-bearing water; occurs in cracks and cavities of igneous rocks, in flintlike nodules in limestones, in mineral veins, in deposits of thermal springs, in siliceous skeletons of various marine organisms (such as diatoms and sponges), in serpentinized rocks, in weathering products, and in most chalcedony and flint. The transparent colored varieties exhibiting opalescence are valued as gemstones. Syn: opalite opalescence

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A milky or somewhat pearly appearance or luster of a mineral, such as that shown by opal and moonstone. CF: play of color opaline a. Any of several minerals related to or resembling opal; e.g., a pale-blue to bluish-white opalescent or girasol corundum, or a brecciated impure opal pseudomorphous after serpentine. AGI b. An earthy form of gypsum. AGI c. A rock with a groundmass or matrix consisting of opal. adj. Resembling opal, esp. in appearance; e.g., opaline feldspar (labradorite) or opaline silica (tabasheer). AGI opalite See: opal opalized wood Silicified wood. See also: wood opal opaque Said of a material that is impervious to visible light or has metallic luster. CF: transopaque; translucent; transparency; transparent; opacity opaque-attrite Attritus that is opaque in thin sections. Syn: opaque-durit Tomkeieff opaque attritus Refers to coal material of which the most prominent and important constituent is opaque matter and also referred to as opaque matrix, black fundamental matter or matrix and residuum. IHCP opaque-durit See: opaque-attrite open area See: effective screening area opencast

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A working in which excavation is performed from the surface. Commonly called open pit. See also: bench; quarry. CF: strip mine Syn: opencut; opencut mine. Webster 3rd opencast method A mining method consisting of removing the overlying strata or overburden, extracting the coal, and then replacing the overburden. When the overlying material consists of earth or clay it can be removed directly by scrapers or excavators, but where rock is encountered it is necessary to resort to blasting to prepare the material into suitable form for handling by the excavators. See also: strip mining opencast mine See: opencast opencast working See: opencast; strike working. open circuit In mineral dressing, a flow line in which the solid particles pass from one appliance to the next without being screened, classified, or otherwise checked for quality; no fraction is returned for retreatment. Pryor, 2 open-circuit mill A grinding mill without classifiers. Nelson open-crib timbering Shaft timbering with cribs alone, placed at intervals. Fay opencut a. To increase the size of a shaft when it intersects a drift so as to form a puddle wall behind the sets of timber. b. Open pit; surface working in which the working area is kept open to the sky. See also: opencast opencut mine An excavation for removing minerals which is open to the weather. See also: opencast opencut mining 2171

See: surface mining; openpit mining. open-drive sampler A drive-type soil-sampling device that is essentially a headpiece, threaded to fit a drill rod, to which is attached a removable length of thin-wall brass or steel tubing. An example is the Shelby tube. Long open end method A method of mining pillars in which no stump is left; the pockets driven are open on the goaf side and the roof is supported on timbers. Lewis opener hole The first hole or holes fired in a round blasted off the solid to create an additional free face in a coal mine. CFR, 4 open fault A fault in which the two walls are separated. CF: closed fault AGI open fire Fire occurring in a roadway or at the coal face in a mine. Such fires may or may not be easily accessible. They may be in the roof of a roadway or seam, or in the kerf of a machine-cut face. However, they are quite distinct in their initiation from gob fires. An open fire may be ignited by a blown-out shot, electrical failure, or from sparks produced by friction. See also: spontaneous combustion open fold A fold in which the limbs diverge at a large angle. AGI open front The arrangement of a blast furnace with a forehearth. Fay open-graded aggregate Mineral aggregate containing very few small particles so that the void spaces are relatively large. Shell open hearth 2172

The form of regenerative furnace of the reverberatory type used in making steel by the Martin, Siemens, and Siemens-Martin processes. See also: furnace; open-hearth furnace. open-hearth furnace A reverberatory melting furnace with a shallow hearth and a low roof. The flame passes over the charge on the hearth, causing the charge to be heated both by direct flame and by radiation from the roof and sidewalls of the furnace. In the ferrous industry, the furnace is regenerative. See also: open hearth open-hearth process A process for manufacturing steel, either acid or basic, according to the lining of the reverberatory furnace, in which selected pig iron and malleable scrap iron are melted, with the addition of pure iron ore. The latter, together with the air, contributes to the oxidation of the silicon and carbon in the melted mass. The final deoxidation is sometimes produced by the addition of a small quantity of aluminum or ferromanganese, which at the same time desulfurizes and recarburizes the metal to the required extent. See also: L Fay open-hearth steel See: open-hearth process open hole a. Coal or other mine workings at the surface or outcrop. Also called opencast; opencut; open pit. b. A borehole that is drilled without cores. Nelson c. Uncased portion of a borehole. Pryor, 3 d. A borehole free of any obstructing object or material. Long opening a. A widening out of a crevice, in consequence of a softening or decomposition of the adjacent rock, so as to leave a vacant space of considerable width. Fay b. A short heading driven between two or more parallel headings or levels for ventilation. Fay c. Surface entrance to mine workings. Syn: mine opening opening out The formation of a longwall face by driving headings and cross headings and connecting the faces to form a continuous line of coal face. It may be viewed as the final stage in development, leading to full coal production. In pillar-and-stall mining, opening out would imply the setting off of the main headings and subsidiary drivages for the formation of coal pillars. See also: branch headings; mechanized heading development. Nelson 2173

openings a. The parts of coal mines between the pillars, or the pillars and ribs. Fay b. A series of parallel chambers or openings, separated by pillars or walls, in slate mining. The width of an opening varies from 35 to 50 ft (11 to 15 m) depending on roof conditions. Nelson opening shot In blasting into solid rock, the wedging shot, gouging shot, or burn cut. Leading shot fired to open up the rock face by creating a cavity and therefore easing the work done by later shots in a round. Pryor, 3 opening stock Quantity on hand at start of accounting period--ore, concentrates, stores, etc. Pryor, 3 open lagging Lagging placed a few inches apart. open light A naked light. Not a safety light. Fay open off a. To turn stalls off stalls, or to drive branch roadways from crossheadings. Nelson b. Eng. To begin the longwall system from the shaft pillar, or the far end of the royalty, or from any headings previously driven out for the purpose of commencing such system. Fay c. To start any new working, as a heading, entry, gangway, room, etc., from another working, as a slope, gangway, etc. Fay openpit mine A mine working or excavation open to the surface. See: strip mine openpit mining a. A form of operation designed to extract minerals that lie near the surface. Waste, or overburden, is first removed, and the mineral is broken and loaded, as in a stone quarry. Important chiefly in the mining of ores of iron and copper. Barger b. The mining of metalliferous ores by surface-mining methods is commonly designated as openpit mining as distinguished from the strip mining of coal and the quarrying of other nonmetallic materials such as limestone, building stone, etc. See also: strip mining 2174

openpit quarry A quarry in which the opening is the full size of the excavation. One open to daylight. Fay open pot Fireclay pot for melting glass--open at the top. Mersereau, 2 open rock Any stratum sufficiently open or porous to contain a significant amount of water or to convey it along its bed. AGI opens Large, open cracks or crevices and small and large caverns. Long open-sand casting Casting made in a mold simply excavated in sand, without a flask. Fay openset Scot. An unfilled space between pack walls. See also: cundy open shop A shop, or mine, where the union price is paid, but where the workers are not all union members. CF: union shop open split A split in which no regulator is installed. Syn: free split Higham open stope a. An unfilled cavity. Nelson b. Underground working place either unsupported, or supported by timbers or pillars of rock. Pryor, 3 open-stope method a. Stoping in which no regular artificial method of support is employed, although occasional props or cribs may be used to hold local patches of insecure ground. The 2175

walls and roof are self-supporting, and open stopes can be used only where the ore and wall rocks are firm. Jackson, 2 b. See: overhand stoping open-tank method A method of treating mine timber to prevent decay in which the timber is immersed in a tank of hot preservative and then in a tank of cold preservative. The preservatives used are creosote, zinc chloride, sodium fluoride, and other chemicals. See also: timber preservation; Bethell's process. Lewis open timbering The usual method of setting timber or steel supports in mines--they are spaced from 2 to 5 ft (0.6 to 1.5 m) apart, with laggings and struts to secure the ground between each set. The method is used in ground that does not crumble or flow. See also: close timbering open-top carrier The main use of this type of bucket elevator has been in handling the product of the larger crushers. Steel buckets of large capacity, which may be as long as 7 ft (2.1 m), are attached rigidly to a heavy flat bar chain, each strand made of two bars with a pitch of 2 and with self-oiling flanged rollers at each intersection. The elevator rises at an angle of about 60 degrees , and the rollers run on ways made of light T-rails. The buckets have overlapping edges, so that there is no spill between them. Pit and Quarry open-top tubbing A length of tubbing having no wedging crib on the top of it. Fay open traverse A surveying traverse that starts from a station of known or adopted position but does not terminate upon such a station and therefore does not completely enclose a polygon. CF: closed traverse open working Surface working, e.g., a quarry or opencast mine. Among the minerals often exploited by open workings are coal, brown coal, gems; the ores of copper, gold, iron, lead, and tin; and all kinds of stone. Also called open work. Nelson operating carrier The mechanism used with the automatic duckbill through which the extension and retraction of the shovel trough are controlled. Jones, 1 2176

operating cost The sum of the costs of mining, beneficiation, and administration gives the operating cost of a mine. Nelson operating engineer See: hoistman operating point A ventilation system is composed of a fan and a set of connected ducts. In a mine ventilation system, mine openings comprise the ducts. At a given air density and with the fan operating at constant speed, there is only one head and quantity of airflow that can result. This is an equilibrium condition and is known as the operating point of the system. Hartman, 2 operation In crystallography, the rotation, reflection, or inversion of an attribute of a crystal structure to complete its symmetry. CF: element operational capacities Figures given on flowsheets to indicate quantities passing various points in plant per unit time, taking account of fluctuations in the rate of supply and composition (as to size and content of impurity), as follows: (1) design capacity, the rate of feed, defined by limits expressing the extent and duration of load variations, at which specific items of plant subject to a performance guarantee must operate continuously and give the guaranteed results on a particular quality of feed; (2) peak design capacity, a rate of feed in excess of the design capacity, which specific items of plant will accept for short periods without fulfilling the performance guarantees given in respect of them; and (3) mechanical maximum capacity, the highest rate of feed at which specific items of equipment, not subject to performance guarantees, will function on the type and quality of feed for which they are supplied. BS, 5 operative temperature Operative temperature is that temperature of an imaginary environment in which, with equal wall (enclosing areas) and ambient air temperatures and some standard rate of air motion, the human body would lose the same amount of heat by radiation and convection as it would in some actual environment at unequal wall and air temperatures and for some other rate of air motion. Strock, 2 ophicalcite 2177

A recrystallized metamorphic rock composed of calcite and serpentine, commonly formed by dedolomitization of a siliceous dolostone. Some ophicalcites are highly veined and brecciated and are associated with serpentinite. AGI ophiolite A group of mafic and ultramafic igneous rocks ranging from spilite and basalt to gabbro and peridotite, including rocks rich in serpentine, chlorite, epidote, and albite derived from them by later metamorphism, whose origin is associated with an early phase of the development of a geosyncline. The term was originated by Steinman in 1905. AGI ophite A general term for diabases that have retained their ophitic structure although the pyroxene is altered to uralite. The term was originated by Palasson in 1819. AGI ophitic Applied to a texture characteristic of diabases or dolerite in which euhedral or subhedral crystals of plagioclase are embedded in a mesotasis of pyroxene crystals, usually augite. Also said of a rock with such a texture. CF: poikilitic optical anomaly Optical properties apparently at variance with optical rules, such as: anisotropy in isotropic minerals, such as birefringent diamond; biaxiality in uniaxial minerals, such as quartz; and erratic variation in birefringence near optical absorption bands--e.g., some epidote minerals. optical calcite Crystalline calcite so clear that it has value for optical purposes; e.g., polarizers. Syn: Iceland spar optical centering device An optical device that enables a theodolite to be accurately positioned over or under a survey station. Also called optical plummet (undesirable usage). BS, 7 optical character The designation as to whether optically positive or optically negative; said of minerals. Fay optical constant 2178

In optical mineralogy, any of the following: indices of refraction, birefringence, optic sign, axial angles, extinction angles, and dispersion of a nonopaque mineral. In ore microscopy (mineragraphy), any of the reflectances and anisotropy of opaque minerals. See also: reflected-light microscope optical crystallography The study of the behavior of light in crystals. Hurlbut optical diffraction Constructive interference of monochromatic light; e.g., labradorescence in plagioclase, fire in opal. See also: diffraction optical flat Glass or other surface rendered truly planar. Pryor, 3 optical glass Carefully made glass of great uniformity and usually special composition to give desired transmission, refraction, and dispersion of light. CCD, 2 optical mineralogy The determination of optical properties of minerals for the purpose of characterization and identification. See also: index of refraction optical property Any of several effects of a substance upon light. Refractive index, double refraction, (and its strength, birefringence), dispersion, pleochroism, and color are gemmologically the most important optical properties. optical pyrometer A type of pyrometer that measures high temperature by comparing the intensity of light of a particular wavelength from the hot material with that of a filament of known temperature. It is used to determine the temperature of incandescent lavas. See also: pyrometer optical sign When a translucent crystal is viewed under microscope, light travels through the mineral at a speed which corresponds with its refractive index, as this is affected by the crystal 2179

planes. A uniaxial crystal has a negative optical sign when the velocity of its extraordinary ray exceeds that of the ordinary ray and vice versa. Calcite is negative; quartz positive. For biaxial crystals, the three principal directions of vibration are mutually at right angles. Pryor, 3 optical square A hand-held instrument enabling right angles to be set out accurately on a site. Hammond optical twinning A type of twinning in quartz in which the parts of the twin are alternately left- and righthanded. So named because it can be recognized by optical tests in distinction to Dauphine (electrical) twinning. Optical twinning as ordinarily applied includes all twin laws in quartz with the exception of the Dauphine. Also called Brazil twinning; chiral twinning. Am. Mineral., 2 optic angle The angle between the two optic axes of a biaxial crystal; its symbol is 2V (less than 90 degrees ), 2Valpha , or 2Vgamma , depending on whether the optic direction X or Z is in the acute bisectrix. Syn: axial angle; optic-axial angle. CF: acute bisectrix; obtuse bisectrix. optic-axial angle See: optic angle optic axis A direction of single refraction in a doubly refracting mineral. Hexagonal and tetragonal minerals have one such axis, and are termed uniaxial; rhombic, monoclinic, and triclinic minerals have two optic axes and are thus biaxial. See also: uniaxial; dispersion. CF: extinction Anderson optics The sub-field of physics that covers the behavior of light. optic sign a. Indicates the type of double refraction in a mineral. In uniaxial minerals, the material is said to be positive when the extraordinary ray has a higher refractive index than the ordinary ray and negative when the ordinary ray has the greater index. In biaxial minerals, which have three basic optical directions, the refractive index of the 2180

intermediate or beta ray is the criterion; if its refractive index is nearer that of the low or alpha ray, it is said to be a positive mineral or stone; if it is nearer the high or gamma ray, it is said to be a negative mineral or stone. b. More technically, in uniaxial minerals, the material is positive when the extreme refractive index (nepsilon ) is greater than the apparently isotropic one (nomega ) and negative when the extreme refractive index is less. In biaxial minerals, which have extreme refractive indices both above and below the apparently isotropic one (nbeta ), the material is positive when the lower refractive index (nalpha ) is closer to the apparently isotropic one and negative when the higher one (ngamma ) is closer. Syn: optical sign; optical character. See also: interference optimization Coordination of various processing factors, controls, and specifications to provide best overall conditions for technical and/or economic operation. Pryor, 4 optimum depth of cut That depth of cut required to completely fill the dipper in one pass without undue crowding. Carson, 1 optimum moisture content The water content at which a soil can be compacted to the maximum dry unit weight by a given compactive effort. Also called optimum water content. ASCE option a. A privilege secured by the payment of a certain consideration for the purchase, or lease, of mining or other property, within a specified time, or upon the fulfillment of certain conditions set forth in the contract. b. S. Afr. The word option may refer to shares under option to the holder of option certificates. In regard to mining activities, options are granted to acquire the mineral rights and/or surface rights over some farm at a price fixed in the agreement. This price may be a sum of money or a participation in a mining company still to be formed. The option itself can be acquired for a lump sum or for a payment of so much per morgen a year. The option contract is generally connected with the permission for the option holder to prospect for minerals and briefly referred to as option and prospecting contract. Beerman optional-flow storage In coal preparation, optional-flow setups are those where coal usually goes to the plant but can be diverted into storage, either in bins or hoppers or on the ground. Coal Age, 3 opx 2181

Abbrev. for orthopyroxene. CF: cpx oral agreement to locate An agreement to locate need not be in writing. If a party, in pursuance of an oral agreement to locate at the expense of another, locates the claim in his or her own name, he or she holds the legal title to the ground in trust for the benefit of the party for whom the location was made. Such a party could, upon making the necessary proofs, compel the locator of the mining claim to convey the title to him or her, although the agreement to do so was not in writing. Such an agreement is not within the statute of frauds. Ricketts orange heat A division of the color scale, generally given as about 900 degrees C. orangepeel A variant of the clamshell bucket with four or five leaves instead of the clamshell's two. Each leaf ends in a reinforced point. Its digging ability is less than that of the clamshell, and its principal use is for underwater excavation and digging. Carson, 1 orangepeel sampler An apparatus consisting of four movable jaws that converge to a point when closed; used to obtain samples of underwater sediment. AGI orbicular Adj. Describes rounded to spherical, commonly banded, textures within minerals or rocks; e.g., orbicular diorite. orbicular structure A structure developed in certain phanerocrystalline rocks (e.g., granite and diorite) due to the occurrence of numerous orbicules. Syn: spheroidal structure; nodular structure. orcelite A hexagonal mineral, Ni5-x As2 ; rose-bronze; at the Tiebaghe massif, New Caledonia. ordered solid solution A condition when atoms in a solid solution arrange themselves in regular or preferential positions in the lattice, rather than at random. Newton, 1 2182

order of crystallization The apparent chronological sequence in which crystallization of the various minerals of an assemblage takes place, as evidenced mainly by textural features. See also: paragenesis order of persistence See: stability series order of reaction A classification of chemical reactions based on the index of the power to which concentration terms are raised in the expression for the instantaneous velocity of the reaction; i.e., on the apparent number of molecules which interact. CTD ordinary kriging A variety of kriging which assumes that local means are not necessarily closely related to the population mean, and which therefore uses only the samples in the local neighborhood for the estimate. Ordinary kriging is the most commonly used method for environmental situations. See also: kriging ordinary ray a. In a uniaxial crystal, that ray that travels with constant velocity in any direction within it. Anderson b. In mineral optics, a light ray that, because of its crystallographic orientation, follows Snell's law, n=sini/sinr, where n is the refractive index, i is the angle of incidence, and r is the angle of refraction. In anisotropic crystals, not all light rays follow Snell's law and are, hence, "extraordinary rays." CF: law of refraction ordinate Y-axis; the vertical scale of a graph. ordnance bench mark Survey station the level of which has been officially fixed with reference to the ordnance datum, the arbitrary mean sea level at Newlyn in Cornwall, England. Pryor, 3 ordnance survey Originally, a military mapping activity; now a precise survey maintained by government which maps land and building features of Great Britain in close detail. Pryor, 3 2183

ordonezite A tetragonal mineral, ZnSb2 O6 ; brown. ore a. The naturally occurring material from which a mineral or minerals of economic value can be extracted profitably or to satisfy social or political objectives. The term is generally but not always used to refer to metalliferous material, and is often modified by the names of the valuable constituent; e.g., iron ore. See also: mineral; mineral deposit; ore mineral. Syn: orebody b. The term ores is sometimes applied collectively to opaque accessory minerals, such as ilmenite and magnetite, in igneous rocks. AGI ore band Zone of rock rich in ore. ore-bearing fluid See: hydrothermal solution ore bed a. Metal-rich layer in a sequence of sedimentary rocks. AGI b. Economic aggregation of minerals occurring between or in rocks of sedimentary origin. ore bin a. A receptacle for ore awaiting treatment or shipment. Fay b. Robustly constructed steel, wooden, or concrete structure which receives intermittent supplies of mined ore and can transfer them continuously by rate-controlled withdrawal systems (bottom gates and ore feeders) to the treatment plant. Thus a buffer stock is held which allows a mine to hoist ore intermittently without bringing milling operations to a standstill. It characteristically receives a weighed-in input of finely broken ore from the final dry-crushing section (usually between 1-in and 3/8-in (2.54-cm and 9.5-mm) maximum particle size). The surge bin is a much smaller one, able to receive a dumped load of run-of-mine ore and to transfer it at a regular rate to the crushing system between arrivals of further skip loads. Pryor, 3 ore blending Method whereby a mine, or a group of mines, served by a common mill, sends ores of slightly varied character for treatment and separate bins or stockpiles are provided. From these, regulated percentages of ores are drawn and blended to provide a steady and predictable feed to the mineral dressing plant. Pryor, 3 2184

ore block A section of an orebody, usually rectangular, that is used for estimates of overall tonnage and quality. See also: blocking out ore blocked out See: developed reserve ore boat A boat constructed esp. for transporting iron ore on the Great Lakes. Mersereau, 2 orebody A continuous, well-defined mass of material of sufficient ore content to make extraction economically feasible. See also: ore; mineral deposit. AGI ore boil A reaction that occurs in an open-hearth furnace in which the carbon monoxide released by the oxidation of carbon causes a violent agitation of the metal as it escapes. Newton, 1 ore bridge A large electric gantry-type crane which, by means of a clamshell bucket, stocks ore or carries it from a stockpile into bins or a larry car on a trestle. Fay ore-bridge bucket A clamshell grab bucket of 5 to 7 tons capacity. Fay ore car A mine car for carrying ore or waste rock. Weed, 2 ore chute An inclined passage, from 3 to 4 ft (approx. 1 m) square, for the transfer of ore to a lower level, car, conveyor, etc. It may be constructed through waste fills. See also: orepass ore cluster

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A genetically related group of orebodies that may have a common root or source rock but that may differ structurally or otherwise. AGI ore control Any tectonic, lithologic, or geochemical features considered to have influenced the formation and localization of ore. AGI ore crusher a. A machine for breaking up masses of ore, usually prior to passing through stamps or rolls. See also: crusher b. See: crusher man ore delfe a. Ore lying underground. b. Right or claim to ore from ownership of land in which it is found. ore deposit a. A body of ore. See also: mineral deposit b. A mineral deposit that has been tested and is known to be of sufficient size, grade, and accessibility to be producible to yield a profit. (In controlled economies and integrated industries, the "profit" decision may be based on considerations that extend far beyond the mine itself, in some instances relating to the overall health of a national economy.) ore developed See: positive ore ore developing Ore exposed on two sides. First class, blocks with one side hidden; second class, blocks with two sides hidden; third class, blocks with three sides hidden. See also: probable ore ore dike An injected wall-like intrusion of magmatic ore, forced in a liquid state across the bedding or other layered structure of the invaded formation. Schieferdecker ore district A combination of several ore deposits into one common whole or system. ore dressing 2186

The cleaning of ore by the removal of certain valueless portions, such as by jigging, cobbing, vanning, etc. See also: concentration; beneficiation; preparation. Syn: mineral dressing; ore preparation. Fay ore expectant The whole or any part of the ore below the lowest level or beyond the range of vision. The prospective value of a mine beyond or below the last visible ore, based on the fullest possible data from the mine being examined, and from the characteristics of the mining district. See also: possible ore; prospective ore. Fay ore face An orebody that is exposed on one side, or shows only one face, and of which the values can be determined only in a prospective manner, as deducted from the general condition of the mine or prospect. Fay ore-forming fluid A gas or fluid that dissolves, receives by fractionation, transports, and precipitates ore minerals. A mineralizer is typically aqueous, with various hyperfusible gases (CO2 , CH4 , H2 S, HF), simple ions (H+ , HS, Cl- , K, Na, Ca), complex ions (esp. chloride complexes), and dissolved base and precious metals. Syn: geologic mineralizer; mineralizer; hydrothermal solution. ore genesis The origin of ores. ore geology The branch of applied geology dealing with the genetic study of ore deposits. Syn: metallogeny; mining geology. See also: economic geology oregonite Probably Ni2 FeAs2 ; hexagonal. From Josephine Creek, Josephine County, OR. Named from the locality. Also spelled oregonit. Hey, 2 ore grader In metal mining, a person who directs and regulates the storage of iron ores of various grades in bins at shipping docks so that the grade of ore contained in each bin will contain the approximate percentage of iron guaranteed to the buyer (iron and steel mills). DOT 2187

ore guide Any natural feature--such as alteration products, geochemical variations, local structures, or plant growth--known to be indicative of an orebody or mineral occurrence. AGI ore hearth A small, low fireplace surrounded by three walls, with a tuyere at the back. Three important types are called: ore hearth, waterback ore hearth, and Moffet ore hearth; used in smelting. Fay oreing down A blocking operation in which ore is added to an open-hearth bath to oxidize the bath and to further reduce the carbon. Henderson ore in sight a. A term frequently used to indicate two separate factors in an estimate, namely: (1) ore blocked out; i.e., ore exposed on at least three sides within reasonable distance of each other; and (2) ore that may be reasonably assumed to exist, though not actually blocked out; these two factors should in all cases be kept distinct, because (1) is governed by fixed rules, while (2) is dependent upon individual judgment and local experience. The expression ore in sight as commonly used in the past, appears to possess so indefinite a meaning as to discredit its use completely. The terms positive ore, probable ore, and possible ore are suggested. b. See: developed reserve ore intersection The point at which a borehole, crosscut, or other underground opening encounters an ore vein or deposit; also, the thickness of the ore-bearing deposit so traversed. Long ore magma A term proposed by Spurr (1923) for a magma that may crystallize into an ore; the sulfide, oxide, or other metallic facies of a solidified magma. AGI ore microscope See: reflected-light microscope ore microscopy The study of opaque ore minerals in polished section with a reflected-light microscope. See also: reflected-light microscopy; microscopy. AGI 2188

ore mineral The part of an ore, usually metallic, which is economically desirable, as contrasted with the gangue. See also: ore ore partly blocked Said of an orebody that is only partly developed, and the values of which can be only approx. determined. See also: probable ore orepass A vertical or inclined passage for the downward transfer of ore; equipped with gates or other appliances for controlling the flow. An orepass is driven in ore or country rock and connects a level with the hoisting shaft or with a lower level. See also: ore chute ore personal property Ore, or other mineral product, becomes personal property when detached from the soil in which it is imbedded. Ricketts ore pipe A long and relatively thin deposit commonly formed at the intersection of two planes. See also: pipe ore plot A place where dressed ore is kept. Fay ore pocket a. Excavation near a hoisting shaft into which ore from stopes is moved, preliminary to hoisting. Pryor, 3 b. Used in a phrase such as a rich pocket of ore, to describe an unusual concentration in the lode. Pryor, 3 ore preparation See: ore dressing ore province A well-defined area containing ore deposits of a particular kind; e.g., the porphyry copper deposits of the Southwestern United States. Related to, but not exactly synonymous with, metallogenic province, which need not contain economic ore deposits. 2189

ore reserve a. The term is usually restricted to ore of which the grade and tonnage have been established with reasonable assurance by drilling and other means. Nelson b. The total tonnage and average value of proved ore, plus the total tonnage and value (assumed) of the probable ore. Hoover c. A mine's substantial asset, without which none of the surface works are economically viable. A body of ore that has been proved to contain a sufficient tonnage of amenable valuable mineral to justify the mining enterprise. The British Institution of Mining and Metallurgy, which regulates the professional standards of its membership, considers that the term ore reserves should be restricted to ore of which the quantity and grade have been established with reasonable assurance by a responsible, professionally qualified person. Additional ore insufficiently developed or tested for inclusion in ore reserves should be clearly described in simple terms best suited to the circumstances; modes of mineral occurrence vary too widely to permit standardization of categories. Pryor, 3 d. S. Afr. Orebodies made available for mining through drives connected by winzes (a connection driven down) and raises (a connection driven up), thus forming blocks that are accessible from four sides. Some companies record partially developed ore reserves in which this making of blocks has not been completed. Newcomers in gold mining occasionally speak of ore reserves when they mean the orebodies contained in a mining area and in copper mining this method of expression has been accepted by large concerns. Beerman e. See: reserve ore sampling The process in which a portion (sample of ore) is selected in such a way, that its composition will represent the average composition of the entire bulk of ore. Such a selected portion is a sample, and the art of properly selecting such a sample is called sampling. Newton, 1 ore separator A cradle, frame, jigging machine, washer, or other device or machine used in separating the metal from broken ore, or ore from worthless rock. Standard, 2 ore shoot a. An elongate pipelike, ribbonlike, or chimneylike mass of ore within a deposit (usually a vein), representing the more valuable part of the deposit. Syn: shoot b. Concentration of primary ore along certain parts of a rock opening. Bateman, 2 c. A large and visually rich aggregation of mineral in a vein. It is a more or less vertical zone or chimney of rich vein matter extending from wall to wall, and has a definite width laterally. Sometimes called pay streak, although the latter applies more specif. to placers. d. An area of payable lode surrounded by low values. See also: shoot Spalding ore sill 2190

A tabular sheet of magmatic ore, injected in a liquid state along the bedding planes of a sedimentary or other layered formation. ore stamp A machine for reducing ores by stamping. Standard, 2 ore-storage drier man One who removes moisture from ore or other material preparatory to roasting or electrolytic processing, using a gas or hot-air drier. Also called drier operator. DOT ore strand Individual mass of quartz with a halo of alteration and ore minerals, or close assemblage of seams of such quartz and accompanying altered ground. AGI ore trend A term used on the Colorado Plateau to indicate the extension of an orebody along its major axis; the average trend of ore in a particular area, or the regional trend of mineralization over a large area. The local trend of individual orebodies may vary from the regional trend of so-called mineral belts. Ballard ore vein A tabular or sheetlike mass of ore minerals occupying a fissure or a set of fissures and later in formation than the enclosing rock. Schieferdecker ore washer A machine for washing clay and earth out of earthy brown hematite ores. The log washer is a common type. Fay ore zone A horizon in which ore minerals are known to occur. Long Orford process A process for separating the copper and nickel in the matte obtained by Bessemerizing. The matte, which consists of copper-nickel sulfides, is fused with sodium sulfide, and a separation into two layers, the top rich in nickel and the bottom rich in copper, is obtained. Also known as top-and-bottom process. CTD 2191

organ A series of closely spaced props placed at the borders of the chamber at the coal face. Such an arrangement protects the future, adjoining chamber from caving. Stoces organic Being, containing, or relating to carbon compounds, esp. in which hydrogen is attached to carbon whether derived from living organisms or not. Usually distinguished from inorganic or mineral. CF: inorganic Webster 3rd organic ash Ash in coal derived from the incombustible material contained in plants. Tomkeieff organic colloid Any of the depressants used in the flotation process. They include glue, gelatin, albumen, dried blood, casein (proteins), tannin, licorice, quebracho extract, and saponin (complex polyhydroxy carboxylic acids and glucosides). Pryor, 3 organic deposit A rock or other deposit formed by organisms or their remains. organic efficiency The ratio (normally expressed as a percentage) between the actual yield of a desired product and the theoretically possible yield (based on the reconstituted feed), both actual and theoretical products having the same percentage of ash. BS, 5 organic soil A general term applied to a soil that consists primarily of organic matter such as peat soil and muck soil. AGI organic sulfur The difference between the total sulfur in coal and the sum of the pyritic sulfur and sulfate sulfur. BS, 1 organic test

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A test in which organic matter in soil is destroyed by oxidizing agents and the loss measured. This test is used in preparation of soil for a sedimentation test, and gives an indication of the amount of organic matter present. See also: sedimentation test organogenic Derived from or composed of organic materials; e.g., a crinoidal limestone. organolite Rock formed from organic substances, esp. those of vegetable origin, such as coal, oil, resins, and bitumens. Tomkeieff orichalcum An ancient copper alloy resembling gold in color. Hess orient a. To place a deflection wedge in a borehole in such an attitude that the concave surface is pointed in a predetermined direction. Long b. To place a piece of core in the same relative plane as it occupied below the surface. See also: core orientation c. To turn a map or planetable sheet in a horizontal plane until the meridian of the map is parallel to the meridian on the ground. Seelye, 2 d. In a transit, to turn the instrument so that the direction of the 0 degrees line of its horizontal circle is parallel to the direction it had in the preceding, or in the initial, setup. Seelye, 2 e. To place a diamond in a bit mold in such an attitude that when it is embedded in the crown matrix one of its hard vector planes will come in contact with the rock to be abraded or cut by the diamond. Long f. The characteristic sheen and irridescence displayed by pearl. Anderson g. To align an optical or crystallographic direction of a mineral with a rotation axis of a microscope stage. oriental a. Frequently used in the same sense as precious when applied to minerals; from an old idea that gems came principally from the Orient; e.g., oriental amethyst, oriental chrysolite, oriental emerald, and oriental topaz, all of which are varieties of sapphire. Syn: precious Fay b. Specially bright, clear, pure, and precious; said of gems. Standard, 2 oriental alabaster Calcium carbonate in the form of onyx marble. Gibraltar stone. Syn: Algerian onyx; onyx marble. Hess; CTD 2193

oriental cat's-eye See: cat's-eye; tiger's-eye. oriental powder An explosive consisting of tan bark, sawdust, or other vegetable fiber, or resins, such as gamboge, impregnated with a nitrate or chlorate and mixed with gunpowder. Standard, 2 orientation a. Arrangement in space of the axes of a crystal with respect to a chosen reference or coordinate system. See also: preferred orientation ASM, 1 b. In surveying, the rotation of a map (or instrument) until the line of direction between any two of its points is parallel to the corresponding direction in nature. c. In structural petrology, refers to the arrangement in space of particles (grains or atoms) of which a rock is composed. AGI d. The act or process of setting a diamond in the crown of a bit in such an attitude that one of its hard vector planes will contact the rock and be the surface that cuts or abrades it. e. As used in borehole surveying and directional drilling practice, orientation refers to the method and procedure used in placing an instrument or tool, such as a deflection wedge, in a drilled hole so that its directional position, bearing, or azimuth is known. Long f. The position of important sets of planes in a crystal in relation to any fixed system of planes. CTD g. The spatial relationship between crystallographic axes and principle optic directions in anisotropic minerals. h. The characteristic sheen or iridescence displayed by pearl. orientational twinning See: electrical twinning orientation survey In geochemical prospecting, a geochemical survey normally consisting of a series of preliminary experiments aimed at determining the existence and characteristics of anomalies associated with mineralization. This information is then used in selecting adequate prospecting techniques and in determining the factors and criteria that have a bearing on interpretation of the geochemical data. Hawkes, 2 oriented Said of a specimen or thin section that is so marked as to show its original position in space. AGI oriented bit 2194

A surface-set diamond bit with individual stones set so as to bring the hard vector direction or planes of the crystal into opposition with the rock surface to be abraded or cut. See also: orient oriented core A core specimen that can be positioned on the surface as it was in the borehole prior to extraction. Such a core is useful where the general dip of the strata is required from one borehole. A magnetic method may be used to disclose the polarity the core specimen possessed while in situ. See also: true dip; borehole surveying; oriented sample. CF: core orientation oriented core barrel An instrument used in borehole surveying, which marks the core to show its position in space. Hammond oriented diamond A diamond inset in the crown of a bit in such an attitude that one of its hard vector planes will be the surface that cuts or abrades the rock. See also: orient oriented sample See: oriented core oriented specimen a. In structural petrology, a hand specimen so marked that its exact arrangement in space is known. Billings b. In paleontology, a fossil whose position is known in regards to such features as anterior and dorsal sides, dorsal and ventral sides, the axis of coiling, the plane of coiling, etc. AGI oriented survey A borehole survey made by lining up a reference mark on the clinometer case with that on the drill rods, which in turn are oriented as they are lowered into the borehole. orienting coupling A rotatable coupling on a Thompson retrievable wedge-setting assembly that may be set and locked in a predetermined position in reference to the gravity-control member. This places the deflection wedge so as to direct the branch borehole in the desired course. Long 2195

orientite An orthorhombic mineral, Ca2 Mn2+ Mn3+2 Si3 O10 (OH)4 ; forms minute, brown to black, radiating, prismatic crystals. orifice a. In ventilation, a hole in a very thin plate. Mason b. A hole or opening, usually in a plate, wall, or partition, through which water flows, generally for the purpose of control or measurement. Seelye, 1 c. The end of a small tube, such as the orifice of a Pitot tube, piezometer, etc. Seelye, 1 d. An opening through which glass flows. In a feeder, an opening in bottom of spout formed by orifice ring. ASTM e. Opening. Formerly applied to discs placed in pipelines or radiator valves to reduce the fluid flow to a desired amount. Strock, 2 orifice meter A form of gas or liquid flowmeter consisting of a diaphragm in which there is an orifice placed transversely across a pipe; the difference in pressure on the two sides of the diaphragm is a measure of flow velocity. Lowenheim orifice of passage Said of a fan with an orifice comparable to the equivalent orifice of a mine; i.e., the area in a thin plate that requires the same pressure to force a given volume of air through as is required to force the same volume through the fan. Orifice of passage O = 0.389 Q/w.g.f., where Q = volume of air passing in thousands cubic feet per minute; w.g.f.= loss of pressure in the fan in inches of water gage. Nelson origin The source or ground of the existence of anything, either as cause or as occasion; that from which a thing is derived or by which it is caused; esp., that which initiates or lays the foundation; e.g., the origin of ore deposits. Standard, 2 original dip The attitude of sedimentary beds immediately after deposition. Syn: initial dip; primary dip. AGI original hole See: main hole original lead 2196

The common lead in a uranium mineral. AGI original mineral See: primary mineral ormolu a. Gold ground for use in gilding; also metal gilded with ground gold. Webster 3rd b. A brass made to imitate gold and used in mounts for furniture and for other decorative purposes. Also called mosaic gold. Webster 3rd ornamental stone See: gemstone ornansite A stony meteorite composed of bronzite and olivine in a friable mass of chondri. Hess orocline An orogenic belt with an imposed curvature or sharp bend, interpreted by Carey (1958) as a result of horizontal bending of the crust, or deformation in plan. AGI orogen A belt of deformed rocks, in many places accompanied by metamorphic and plutonic rocks; e.g., the Appalachian orogen or the Alpine orogen. AGI orogenesis See: orogeny orogenic Adj. of orogeny. orogeny The process by which structures within fold-belt mountainous areas were formed, including thrusting, folding, and faulting in the outer and higher layers, and plastic folding, metamorphism, and plutonism in the inner and deeper layers. Syn: orogenesis; mountain building; tectogenesis. Adj: orogenic; orogenetic. AGI 2197

orometer An aneroid barometer having a second scale that gives the approximate elevation above sea level of the place where the observation is made. Webster 3rd oronite An enamel paint for protecting metal surfaces from the action of hot vapors. Fay O'Rourke car switcher A crossover switch that consists essentially of a single-acting cylinder hoist on a crossrail fastened to the roof at right angles to the track. While a car is being loaded, the switcher picks up the empty car next to the locomotive and holds it to one side. As soon as a car is loaded the locomotive pulls the train back past the switcher, and the empty car is placed at the front of the train and pushed under the slide. Lewis orphaned mine land Abandoned and unreclaimed mines for which no owner or responsible party can be found. The reclamation and environmental conditions of such lands is then defaulted to the State or Federal Government. SME, 1 orpiment a. A yellow arsenic trisulfide, As2 S3 , containing 61% arsenic; monoclinic. Syn: yellow arsenic b. A monoclinic mineral, 4[As2 S3 ]; soft; pearly lemon yellow with one perfect cleavage; in powdery foliated masses and coatings, botryoidal or fibrous; a lowtemperature alteration of other arsenides; associated with realgar and gold in hot springs. Syn: yellow ratsbane Orsat gas-analysis instrument An instrument for analyzing flue gases. Although outside its normal field of application, it may be used for analyzing mine air. Nelson orthite A former name for allanite, esp. when found in slender prismatic or acicular crystals. orthoa. A combining form meaning straight; at right angles; proper. AGI b. In petrology, a prefix that, when used with the name of a metamorphic rock, indicates that it was derived from an igneous rock, e.g., orthogneiss, orthoamphibolite; it may also indicate 2198

the primary origin of a crystalline, sedimentary rock, e.g., orthoquartzite as distinguished from metaquartzite. AGI c. A prefix to the name of a mineral species or group to indicate orthorhombic symmetry as opposed to "clino" indicating monoclinic symmetry. orthoamphibole The orthorhombic subgroup of amphiboles including anthophyllite, gedrite, and holmquistite. CF: clinoamphibole orthochlorite a. A group name for distinctly crystalline forms of chlorite (such as clinochlore and penninite). b. A group name for chlorites conforming to the general formula: (R2+ ,R3+ )6 (Si,Al)4 O10 (OH)8 . orthoclase A monoclinic mineral, KAlSi3 O8 ; feldspar group; prismatic cleavage; partly ordered, monoclinic potassium feldspar dimorphous with microcline, being stable at higher temperatures; also a general term applied to any potassium feldspar that is or appears to be monoclinic; e.g., sanidine, submicroscopically twinned microcline, adularia, and twinned analbite. It is a common rock-forming mineral and occurs esp. in granites, granite pegmatites, felsic igneous rocks, and crystalline schists, and is commonly perthitic. Syn: common feldspar; orthose; pegmatolite. CF: microcline; plagioclase; anorthoclase. orthoclase gabbro A descriptive name for rocks now known as monzonite, in which the plagioclase is at least as calcic as labradorite. Holmes, 2 orthoclasite An orthoclase-bearing porphyritic intrusive rock, such as granite or syenite. The term is sometimes restricted to rocks containing more than 90% orthoclase. Not recommended usage. AGI orthoclastic Cleaving in directions at right angles to each other. Webster 3rd orthodolomite a. A primary dolomite, or one formed by sedimentation. AGI b. A term used by Tieje (1921) for a dolomite rock so well-cemented that the particles are interlocking. AGI 2199

orthodome A monoclinic crystal form whose faces parallel the orthoaxis and cut the other axes. CF: dome; clinodome. AGI orthoferrosilite An orthorhombic mineral, (Fe,Mg)2 Si2 O 6 ; pyroxene group; now simply called ferrosilite. CF: ferrosilite; clinoferrosilite. orthogneiss Applied to gneissose rocks that have been derived from rocks of igneous origin. CF: paragneiss orthogonal At right angles. Hammond orthoguarinite Cesaro's name for an orthorhombic form of guarinite, through superposition of hemitropic lamellae of the monoclinic mineral, clinoguarinite. See also: clinoguarinite orthohydrous maceral Maceral having a normal hydrogen content, such as vitrine. Tomkeieff orthokalsilite An artificial orthorhombic high-temperature polymorph of KAlSiO4 . ortholimestone A term proposed by Brooks (1954) for sedimentary limestone. CF: metalimestone; orthomarble. AGI orthomagmatic See: orthomagmatic stage orthomagmatic stage Applied to the main stage of crystallization of silicates from a typical magma; the stage during which perhaps 90% of the magma crystallizes. CF: pegmatitic stage 2200

orthomarble A crystalline limestone that will take a polish; e.g., the Holston orthomarble of Tennessee. CF: metamarble; metalimestone; ortholimestone. orthomic feldspar Triclinic feldspar, which by repeated twinning (orthomimicry) simulates a higher degree of symmetry with rectangular cleavages; e.g., orthoclase, anorthoclase, and cryptoclase. English orthophotography The product of a procedure that corrects the distortions in aerial photography due to the instability of the camera platform, the terrain relief, and the angle of the light rays entering the camera lens. The ortho instrumentation attached to a stereo plotting instrument rectifies the image in a transfer process so as to reposition it in its correct planar position. SME, 1 orthophyric Said of the texture of the groundmass in certain holocrystalline, porphyritic, igneous rocks in which the feldspar crystals have quadratic or short, stumpy, rectangular cross sections, rather than the lath-shaped outline observed in trachytic texture. Also, said of a groundmass with this texture, or of a rock having an orthophyric groundmass. AGI orthopinacoid In the monoclinic system, the form consisting of two planes parallel to the vertical and orthodiagonal axes. See also: pinacoid Standard, 2 orthoprism A monoclinic prism, the orthodiagonal intercept of which is greater than 1. Standard, 2 orthopyroxene The subgroup name for pyroxenes crystallizing in the orthorhombic system, commonly containing no calcium and little or no aluminum; e.g., enstatite, hypersthene, and ferrosilite. CF: clinopyroxene Syn: labrador hornblende orthoquartzite A clastic sedimentary rock that is made up almost exclusively of quartz sand (with or without chert), and relatively free of or lacks a fine-grained matrix, derived by secondary 2201

silicification; a quartzite of sedimentary origin, or a pure quartz sandstone. The term generally signifies a sandstone with more than 90% to 95% quartz and detrital chert grains that are well-sorted, well-rounded, and cemented primarily with secondary silica (sometimes with carbonate) in optical and crystallographic continuity with the grains. The rock is characterized by stable but scarce heavy minerals (zircon, tourmaline, and magnetite), by lack of fossils, and by prominence of cross-beds and ripple marks. It commonly occurs as thin but extensive blanket deposits associated with widespread unconformities (e.g., an epicontinental deposit developed by an encroaching sea), and it represents intense chemical weathering of original minerals other than quartz, considerable transport and washing action before final accumulation (the sand may experience more than one cycle of sedimentation), and stable conditions of deposition (such as the peneplanation stage of diastrophism); e.g., St. Peter Sandstone (Middle Ordovician) of midwestern United States. See also: quartzite AGI orthorhombic a. Any mineral crystallizing with orthorhombic symmetry. b. See: orthorhombic system orthorhombic system In crystallography, that system of crystals whose forms are referred to three unequal mutually perpendicular axes. Syn: prismatic system; rhombic system; orthorhombic. Fay orthoschist A schist derived from an igneous rock. CF: paraschist; schist. AGI orthoscope A polarizing microscope in which light is transmitted by the crystal parallel to the microscope axis, in contrast to the conoscope, in which a converging lens and Bertrand lens are used. CF: conoscope orthose A name for the whole feldspar family before it was divided into separate species. Syn: orthoclase orthotectic See: magmatic orthotectic stage See: orthomagmatic stage 2202

orthotropic The description applied to the elastic properties of material, such as timber, which has considerable variations of strength in two or more directions at right angles to one another. See also: isotropic Hammond Orton cone a. Pyrometric cone made in one of two sizes: 2-1/2 in (6.4 cm) high for industrial kiln control, and 1-1/8 in (3.2 cm) high for pyrometric cone equivalent testing. See also: pyrometric cone b. Used in the United States for heat recording, Orton cones are similar to Seger cones, but the same numbers do not indicate the same temperatures; e.g., Orton cone 14 corresponds to Seger cone 13. Rosenthal oryctognosy The description and systematic arrangement of minerals; mineralogy. See also: mineralogy oryctologist See: mineralogist oryctology See: mineralogy Osann's classification A purely chemical system of classification of igneous rocks. AGI osarizawaite A trigonal mineral, PbCuAl2 (SO4 )2 (OH)6 ; alunite group; the aluminum analog of beaverite; a yellow, powdery secondary crust; at the Osarizawa Mine, Akita prefecture, Japan. oscillating beam See: walking beam oscillating conveyor A type of vibrating conveyor having a relatively low frequency and large amplitude of motion. See also: vibrating conveyor Syn: grasshopper conveyor 2203

oscillating feeder See: conveyor-type feeder oscillating grease table An assembly of 4 to 8 metal trays, usually 30 in (76.2 cm) wide and 8 to 15 in (20.3 to 38.1 cm) long, arranged in series in the direction of flow. The trays are detachably mounted in the assembly by steps, so that the overflow from one tray overlaps the next tray by 1 in (2.54 cm) and is 2 to 4 in (5.1 to 10.2 cm) above it. The trays are inclined downward in the direction of the flow at an angle adjustable from 14 degrees to 18 degrees. The entire assembly is mechanically oscillated transversely to the direction of the flow at about 200 strokes/min with an adjustable stroke of about 1/2 in (1.27 cm). The storage bin and feed roller are independently mounted and discharge a layer 1 grain thick. Chandler oscillation Independent movement through a limited range, usually on a hinge. Nichols, 1 oscillator plate A thin slab of quartz which, by mechanical vibration, controls the frequency of a radio transmitter. Hurlbut oscillator quartz Flawless quartz, which can be used in the manufacture of oscillator plates. oscillatory twinning Repeated twinning in which a crystal is made up of thin lamellae alternately in reversed position; polysynthetic twinning; found in some feldspars. Syn: polysynthetic twinning oscillatory zoning Repetitious concentric compositional variation in minerals resulting from cyclical changes in the chemical environment during crystal growth; e.g., garnet and plagioclase. oscillogram A record of phenomena observed on an oscillograph. ASM, 1 oscillograph 2204

An instrument that renders visible, or automatically traces, a curve representing the time variations of various phenomena. The recorded trace is an oscillogram. AGI oscilloscope An instrument for showing visual representations of electrical outputs from measuring devices. Hunt osmite See: iridosmine osmium The native element, Os; occurs in magmatic deposits in mafic and ultramafic rocks and placers derived from them. osmosis The passage of a solvent through a membrane from a dilute solution into a more concentrated one, the membrane being permeable to molecules of solvent but not to molecules of solute. AGI osteolite A massive, earthy mineral (apatite) consisting of an impure, altered phosphate. ostracod A minute crustacean with a bean-shaped bivalve shell completely enclosing the body. AGI otavite A trigonal mineral, CdCO3 ; calcite group; associated with oxidized base-metal ores. other rock in place As used in the Mining Law of 1872, means any rocky substance containing mineral matter. Ricketts other valuable deposits Includes nonmetalliferous as well as metalliferous deposits. Ricketts 2205

otisca process A process that uses an inert heavy liquid with a specific gravity between that of coal and free mineral matter to separate coarse or fine-size coal in a static bath or cyclone separator. Otisca-T process A selective agglomeration process under development, in which ultra-fine grinding of the feed coal to 15 mu m releases almost all the associated impurities prior to agglomeration with a low-molecular-weight hydrocarbon. The agglomerant is then recovered and recycled. Otto cycle In a four-stroke internal combustion engine two complete revolutions of the crankshaft correspond with the working cycle-inlet stroke (suction downstroke of piston in cylinder); compression upstroke; explosion at peak of compression followed by expansion of hot exploded gases on driving downstroke; rising exhaust stroke to complete the cycle. Pryor, 3 Ouachita stone See: novaculite oued See: wadi outburst The name applied to the violent evolution of combustible gases (usually together with large quantities of coal dust) from a working face. The occurrence is violent and may overwhelm the workings and fill the entire district with gaseous mixtures. Roadways advancing into virgin and stressed areas of coal are particularly prone to outbursts in certain seams and faults often intersect in the area. See also: floor burst; blow; bump. Roberts, 1 outby Nearer to the shaft, and therefore away from the face, toward the pit bottom or surface; toward the mine entrance. The opposite of inby. Also called outbyeside. Syn: out-over outcrop 2206

a. The part of a rock formation that appears at the surface of the ground. Webster 3rd b. A term used in connection with a vein or lode as an essential part of the definition of apex. It does not necessarily imply the visible presentation of the mineral on the surface of the earth, but includes those deposits that are so near to the surface as to be found easily by digging. Fay c. The part of a geologic formation or structure that appears at the surface of the Earth; also, bedrock that is covered only by surficial deposits such as alluvium. CF: exposure outcropping. AGI d. To appear exposed and visible at the Earth's surface; to crop out. AGI outcrop map A special type of geologic map that represents only actual outcrops. Areas without exposures are left blank. Stokes outcropping See: outcrop outcrop water Rain and surface water that seeps downward through outcropping porous and fissured rock, fault planes, old shafts, or surface drifts. AGI outdoor stroke That stroke of a Cornish pumping engine by which the water is forced upward by the weight of the descending pump rods, etc. outer continental shelf All submerged lands lying seaward and outside of the area of lands beneath navigable waters as defined in Section 2 of the Submerged Lands Act (Public Law 31, 83rd Congress, 1st Session), and of which the subsoil and seabed appertain to the United States and are subject to its jurisdiction and control. Abbrev. OCS. See also: continental shelf outer core The outer or upper zone of the Earth's core, extending from a depth of 2,900 km to 5,100 km, and including the transition zone; it is equivalent to the E layer and the F layer. It is inferred to be liquid because it does not transmit shear waves. Its density ranges from 9 to 11 g/cm3 . The outer core is the source of the principal geomagnetic field. CF: inner core outer gage 2207

Syn. for outside diameter. Long outer stone A diamond set on the outside wall of a bit crown. Also called reamer; reamer stone. Syn: outside stone; kicker stone. Long outfall a. Eng. A seam cropping out at a lower level. b. The mouth of a stream or the outlet of a lake; esp. the narrow end of a watercourse or the lower part of any body of water where it drops away into a larger body. AGI c. The vent or end of a drain, pipe, sewer, ditch, or other conduit that carries waste water, sewage, storm runoff, or other effluent into a stream, lake, or ocean. AGI outlay a. The act of laying out or expending. Webster 3rd b. Something that is laid out; expenditure. Webster 3rd c. The cost of equipping a mine and placing it on a producing basis. Fay outlet An opening from a mine to the surface. Syn: upcast outlier a. An isolated mass or detached group of rocks surrounded by older rocks; e.g., an isolated hill or butte. CF: inlier b. Ore or favorable geologic indications distant from the main ore zone of a district. out of gage a. Bits and reaming shells having set inside or outside diameters greater or lesser than those specified as standard. Long b. A borehole the inside diameter of which is undersize or oversize. Long out-over See: outby output a. The quantity of coal or mineral raised from a mine and expressed as being so many tons per shift, per week, or per year. Nelson b. The power or product from a plant or 2208

prime mover in the specific form and for the specific purpose required. See also: concentration of output; productivity. Nelson c. Amount delivered; e.g., volume of a liquid discharged by a pump; volume of air discharged by a compressor; horsepower delivered by a motor. Long d. Current or signal delivered by any circuit or device. NCB e. The terminal or other point at which a current or a signal may be delivered. NCB output device Machine that prints information computed from its memory or store. Pryor, 3 output shaft A shaft that transmits power from a transmission or clutch. Nichols, 1 outrigger An outward extension of a frame that is supported by a jack or block. Used to increase stability. Nichols, 2 outside angling See: angling outside clearance One-half the total difference between the outside diameter of any piece of downhole equipment and the inside diameter of the borehole. Long outside face The peripheral portion or that part of a bit crown, roller bit cutter, or any cutting edge of a bit in contact with the walls of a borehole while drilling. Long outside foreman In bituminous coal mining, a person who supervises all operations at the surface of a mine. DOT outside stone See: outer stone outside tap See: bell tap 2209

outside upset The act or process of thickening a length of tubing at its ends by increasing its outside diameter without changing the inside diameter; a length of tubing or drill rod so processed. See also: upset Long outside wall That part of a bit crown, bit shank, reaming shell, core barrel, drill rod, casing, or other piece of downhole equipment that when in use, comes in contact with the wall of a borehole. Long outside work Drilling operations conducted on the surface, as opposed to drilling done in underground or enclosed workplaces. Long outslope The face of the spoil or embankment sloping downward from the highest elevation to the toe. outstation A location which provides local monitoring and control, and provides a communications interface between a sensor and the trunk connected to a central station computer. Also called field data station. SME, 1 outtake The passage by which the ventilating current is taken out of the mine; the upcast. The return air course. An outlet. Fay oval socket A fishing tool used to recover broken drill rods from a borehole. Long oven A chamber in which substances are artificially heated for the purposes of baking, roasting, annealing, etc.; specif.: (1) a kiln, such as a coke oven; and (2) a leer, which is used in glassmaking. Standard, 2 overaging 2210

Aging at a higher temperature, or for a longer time, or both, than required for critical dispersion, thus causing particle agglomeration of the precipitating phase and, as a result, loss of strength and hardness. See also: aging overall concentration The ratio of pithead output in tons (P) to length of main haulage roads in yards (L) or tons per yard of main haulage roads; i.e., P/L. See also: concentration of output overall drilling time The sum of the times required for actual rock drilling, setting up and withdrawal, moving drills from hole to hole and machine delays. The overall drilling time is a better basis for estimating drilling efficiency than penetration speed alone. Nelson overall efficiency a. Of an air compressor, the product of the compression efficiency and the mechanical efficiency. Fay b. Ratio of power output of an engine to the power input; the measure of the difference between indicated and brake horsepower. Brantly, 2 overall fan efficiency The ratio of the horsepower in the air to the horsepower absorbed by the driving motor of the fan. BS, 8 overall reduction ratio With reference to a crusher, mean size of feed/mean size of product. See also: reduction ratio overall ventilation efficiency The ratio between the air horsepower and the indicated horsepower of a driving unit. The percentage is expressed by air horsepower x 100/indicated hp of driving unit. Measurements are taken of the air pressure and volume in the fan drift, and the power absorbed by the driving unit. See also: volumetric efficiency; thermometric fan test. Nelson over-and-under conveyor Two endless chains or other linkage between which carriers are mounted and controlled, so that the carriers remain in an upright and horizontal position throughout the complete cycle of the conveyor. 2211

overarching weight The pressure of the rocks over active mine workings. It is the roof weight that acts on the packs and the solid coal in the working area. See also: abutment; nether roof; underweight. Nelson overbreak Excessive breakage of rock beyond the desired excavation limit. See also: neat lines overbreaking See: overhand stoping overburden a. Designates material of any nature, consolidated or unconsolidated, that overlies a deposit of useful materials, ores, or coal--esp. those deposits that are mined from the surface by open cuts. Stokes b. Loose soil, sand, gravel, etc. that lies above the bedrock. Also called burden, capping, cover, drift, mantle, surface. See also: baring; burden; top. Stokes overburden bit A special diamond-set bit, similar to a set casing shoe, used to drill casing through overburden composed of sand, gravel, boulders, etc. Long overburden drilling a. A technique developed in Sweden that involves the sinking, by percussive-rotary drilling, of a drill casing through the overburden to where it seats in the underlying rock. A rotary percussion drill hole is then continued to the desired depth in the rock. While the casing is being sunk through the overburden it is coupled to the drill rod and rotates and reciprocates with it. The rock bit on the end of the drill rod projects about an inch beyond the end of the ring bit with which the casing is fitted and acts as a pilot bit for the casing bit. Woodruff b. A drilling method whereby drilling is carried out through subsoil and boulders or underwater to and through bedrock. Eng. Min. J., 2 overcast a. An enclosed airway that permits an air current to pass over another one without interruption. Syn: overcrossing; overgate. CF: undercast See also: air crossing b. To place the overburden removed from coal in surface mines in an area from which the coal has been mined. c. Pushed forward, so as to overlie other rocks, such as in thrust faults. See also: jack pit 2212

overcasting A procedure used in certain mining activities including strip mining and in some heavy construction work such as channel excavation. Overcasting may be performed in a simple operation consisting of digging out the material, lifting it from one position, moving it over, and dumping it in the spoil position where it remains, for practical purposes, indefinitely. The mechanics of the operation are called "simple overcasting." Woodruff overcharging Adding material in excess of the capacity of the equipment used for processing. overconsolidated soil deposit A soil deposit that has been subjected to an effective pressure greater than the present overburden pressure. ASCE overcrossing See: air crossing; overcast. overcurrent relay Relay used to trip circuit breakers when an abnormal current of two to three times the normal flow is detected in a circuit. Relays are adaptable to transmission lines, buses, feeder circuits, transformers, and motors. Coal Age, 3 overcut a. A machine cut made along the top or near the top of a coal seam; sometimes used in thick seams or a seam with sticky coal. By releasing the coal along the roof, its mining becomes easier. See also: overcut; turret coal cutter. Nelson b. The process of producing a larger size hole than the outside diameter of a bit and/or reaming shell used, due to the eccentric rotational movements of the bit, core barrel, or drill stem. Long overcutting machine Coal-cutting machine that is an adaptation of a shortwall machine, designed to make the cut, or kerf, at desired place in the coal seam some distance above the floor. The main difference between an overcutting machine and an ordinary shortwall machine is that the cutter bar in the overcutting machine is mounted at the top of the machine instead of at the bottom. See also: turret coal cutter overdense medium 2213

Medium of specific gravity greater than that in the separating bath; usually produced in the medium recovery system and used to maintain the desired specific gravity in the bath. BS, 5 overdrilling The act or process of drilling a run or length of borehole greater than the core-capacity length of the core barrel, resulting in loss of the core. Long overdrive The act of inducing a velocity higher than the steady state velocity in a column of explosive material upon detonation by the use of a powerful primer or booster; it is a temporary phenomenon and the explosive quickly assumes its steady state velocity. overfired A term related to the condition of a ceramic product which has been heated to a temperature in excess of that required to produce proper vitrification. overfiring Heating ceramic materials or ware above the temperature required to produce the necessary degree of vitrification. Usually results in bloating, deformation, or blistering of the ware. overflow stand A standpipe in which water rises and overflows at the hydraulic gradeline. Seelye, 1 overgate See: air crossing; overcast. overgrinding Comminution of ore to a smaller particle size than is required for effective liberation of values before concentrating treatment. Opposite of undergrinding. Pryor, 3 overhand cut-and-fill In this method, two level drives are first connected, the lower and upper one by a raise, from the bottom of which mining is begun. The work proceeds upwards, filling the mined-out room, but in the filling, chutes are left through which the broken ore falls. In inclined seams the chutes, also inclined, have to be timbered. The lower-level drive is 2214

protected either by timbering or vaulting, or by a fairly strong pillar of vein fillings. Stoping in the different cuts always proceeds upwards, but as a whole it proceeds between the two level drives in a horizontal direction. Overhand cut-and-fill, esp. in mining irregular orebodies of greater size, is also called back stoping. Stoces overhand stope a. Stope in which the ore above the point of entry to the stope is attacked, so that severed ore tends to gravitate toward discharge chutes and the stope is self-draining. Pryor, 3 b. An overhand stope is made by working upward from a level into the ore above. McKinstry overhand stoping a. In this method, which is widely used in highly inclined deposits, the ore is blasted from a series of ascending stepped benches. Both horizontal and vertical holes may be employed. Horizontal breast holes are usually more efficient and safer than vertical upper holes, although the latter are still used in narrow stopes in steeply inclined orebodies. McAdam, 2 b. The working of a block of ore from a lower level to a level above. In a restricted way overhand stoping can be applied to open or waste-filled stopes that are excavated in a series of horizontal slices either sequentially or simultaneously from the bottom of a block to its top. Stull timbering or the use of pillars characterize the method. Filling is used in many instances. Modifications are known as backfilling method; back stoping; block system; block system of stoping and filling; breast stoping; combined side and longwall stoping; crosscut method of working; cross stoping; Delprat method; drywall method; filling system; filling-up method; flatback stoping; longwall stoping; open cut system; open stope and filling; open-stope method; open-stope, timbering with pigsties, and filling; overhand stoping on waste; resuing; rock filling; room-and-pillar with waste filling; sawtooth back stoping; side stoping; slicingand-filling system; stoping and filling; stoping in horizontal layers; transverse with filling. Syn: combined side and longwall stoping; Delprat method; overbreaking. CF: back-filling system; chimney work; underhand stoping. overhand stoping and milling system See: combined overhand and underhand stoping overhand stoping on waste See: overhand stoping overhand stoping with shrinkage and delayed filling See: shrinkage stoping 2215

overhand vertical slice See: square-set stoping overhang a. Cliff overhang. AGI b. A part of the mass of a salt dome that projects out from the top of the dome much like the cap of a mushroom. AGI overhaul a. Describes a condition when a journey travels towards a haulage engine at a faster rate than the rope, which then becomes slack and liable to foul the drum. Also called overrun. Nelson b. The transportation of excavated material beyond certain specified limits. Seelye, 1 c. In many highway contracts, a movement of dirt far enough so that payment, in addition to excavation pay, is made for its haulage. Nichols, 1 d. Applied to inspection, cleaning, and repairing of machines or plant. Nelson overhead cableway A type of equipment for the removal of soil or rock. It consists of a strong overhead cable, usually attached to towers at either end, on which a car or traveler may run back and forth. From this car a pan or bucket may be lowered to the surface, subsequently raised and locked to the car, and transported to any position on the cable where it is desired to dump its contents. overhead conveyor See: trolley conveyor overhead monorail This system is popular for use in mines since it can be suspended from the roadway supports as the face advances and can carry supplies over equipment installed in the roadway; transport is by means of endless, main-and-tail, or main-rope winches. They are generally slow-moving and can carry light loads into and around many places inaccessible to other forms of transport. See also: monorail overhead-rope monorail In this system, the loads are carried by bogies running on a taut wire rope instead of steel joists or flat-bottomed rails. See also: monorail Sinclair, 3 overhead ropeway 2216

See: aerial ropeway overhead shovel A tractor loader that digs at one end, swings the bucket overhead, and dumps at the other end. Nichols, 1 overhead traveling crane A crane that traverses the whole width of a workshop along the rails on which it runs. Hammond overhead trolley conveyor See: trolley conveyor overlap a. A general term referring to the extension of marine, lacustrine, or terrestrial strata beyond underlying rocks whose edges are thereby concealed or overlapped, and to the unconformity that commonly accompanies such a relation; esp. the relationship among conformable strata such that each successively younger stratum extends beyond the boundaries of the stratum lying immediately beneath. CF: onlap b. The area common to two successive aerial or space photographs or images along the same flight strip, expressed as a percentage of the photo area. AGI c. The portion of a borehole that must be redrilled after caving of the hole, cementing a section of the hole, or bypassing unrecoverable material. Long d. A reversed fault or thrust. BS, 11 e. The lineal portion of a branch hole that nearly parallels the parent hole. Long overlap auxiliary ventilation To combine the forcing and exhausting systems, it is not necessary to provide two ducts, one forcing and one exhausting, throughout the length of the heading. An arrangement that serves the same purpose is the overlap system. In this system a main exhausting duct is used within a convenient distance of the face, often about 100 ft (30.5 m). Some of the intake air in the heading, before reaching the end of this duct, enters a short length of tubing and is blown onto the face. The advantages of both systems are thus obtained. Precautions must be taken against recirculation of air by the forcing unit, to prevent concentration of dust, and in collieries, combustible gases, at the face. The two ducts must overlap by a minimum distance which, in practice, is usually taken as 30 ft (9.1 m). See also: auxiliary ventilation Roberts, 1 overlap fault

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a. See: thrust fault b. A fault structure in which the displaced strata are doubled back upon themselves. AGI overlay a. Scot. The material above the rock in a quarry. See also: overburden Fay b. Graphic data on a transparent or translucent sheet to be superimpossed on another sheet (such as a map or photograph) to show details not appearing, or requiring special emphasis, on the original. Also, the medium or sheet containing an overlay. AGI overlay tracing A tracing on which the workings in a seam are shown. A series of such tracings allows the workings in several seams to be seen in their correct horizontal relationship. Also called layover tracing (undesirable usage). BS, 7 overload a. In general, a load or weight in excess of the designed capacity. The term may be applied to mechanical and electrical engineering plants, to loads on buildings and structures, and to excess loads on haulage ropes and engines. Nelson b. To apply an excessive pressure, by stretching beyond the yield point, to a drill string and bit. CF: crowd overloader A loading machine of the power-shovel type for quarry and opencast operations. It may be either pneumatic-tired or continuous-tracked. It need not turn from the face to the truck if the latter can be spotted parallel to the face. The bucket is filled, the machine retracted, and the bucket swung over to the discharge point; used chiefly in sand and gravel pits. Nelson overmining S. Afr. Mining a grade of ore above the average grade of the ore reserves. This practice has the effect of leaving the lower grade ore in the reserves. The opposite is undermining. Beerman overpoled copper In refining blister copper by reducing its oxides through stirring a molten bath of metal with a green timber pole, continuation of this process until the desirable characteristic fracture of tough-pitch refined metal is lost. Some reoxidation then becomes necessary. See also: tough pitch 2218

overprint The superposition of a new set of structural features on an older set. Syn: superprint; metamorphic overprint. AGI override A royalty or percentage of the gross income from production deducted from the working interest. Wheeler, R.R. overriding royalty The term applied to a royalty reserved in a sublease or assignment over and above that reserved in the original lease. Ricketts overrope A winding or hoisting rope. Fay overrope haulage Usually applied to endless rope haulage in which the rope is carried on top of the mine cars, which may be either clipped or lashed to the rope. See also: underrope haulage overrun See: overhaul overrun brake A special brake fitted to a towed vehicle that operates as soon as the towing vehicle slows down. Hammond overrunning clutch A coupling that transmits rotation in only one direction, and disconnects when the torque is reversed. Nichols, 1 oversaturated rock A rock that contains silica in excess of that necessary to form saturated minerals from the bases present. CF: saturated rock overshot 2219

A fishing tool for recovering lost drill pipe or casing. Inst. Petrol. overside Discharging over the side; e.g., by a dredge. Standard, 2 oversize a. In reference to a mixture of material screened or classified into two products of definite size limits, the larger is the oversize and the smaller the undersize. See also: classifier b. In quarry or opencast blasting, that size of rock or ore which is too large to handle without secondary blasting. Nelson oversize control screen A screen used to prevent the entry into a machine of large particles that might interfere with its operation. Syn: guard screen; check screen. BS, 5 oversize core a. Core cut by a thin-wall bit, as opposed to a standard-diameter core. Long b. A core the diameter of which is greater than a standard size. Long oversize coupling a. See: swelled coupling b. Sometimes used in Canada as a synonym for reaming shell. Long oversize hole A borehole the diameter of which is excessive because of the whipping action or eccentric rotation of the drill string and bit. Long oversize rod See: drill collar; guide rod. overspringing See: springing overstressed area

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In strata control, describes an area where the force is concentrated on pillars. This type of area is said to be overstressed or superstressed. This superstressing is limited by the strength of the seam or pillar. CF: destressed area Overstrom table Similar to a Wilfley table but of diamond shape (rhomboid), thus eliminating the waste corners. Liddell over-the-road hauling Hauling over public highways, usually by a dump truck. Various restrictions, such as weight, width of vehicle, safety features, guard against spillage, etc. must be considered in the type equipment used. CF: off-the-road hauling overthrust A low-angle thrust fault of large scale, with displacement generally measured in kilometers. CF: underthrust AGI overthrust block See: overthrust nappe overthrust fault See: overthrust overthrust nappe The body of rock that forms the hanging wall of a large-scale overthrust; a thrust nappe. Syn: overthrust block; overthrust sheet; overthrust slice. AGI overthrust plane See: thrust plane overthrust sheet See: overthrust nappe overthrust slice See: overthrust nappe 2221

overtime The period beyond the normal shift time when a worker, on request by the management, performs emergency tasks that are necessary for safety or efficient operation of the oncoming shift. Nelson overtopping Flow of water over the top of a dam or embankment. Nichols, 1 overtravel See: overwind overtub system An endless-rope system in which the rope runs over the tubs or cars in the center of the rails. This system is generally adopted on undulating roads, where the tension in a heavily loaded rope would cause the rope to lift in swilleys and derail tubs. It is also generally adopted in highly inclined roads, as the lashing chain, often adopted with this method of haulage, obtains a good positive grip on the rope and is easier to detach than a clip. The rope is kept from rubbing on roof supports by holding-down pulleys: six or eight small pulleys are mounted in circular cheeks, allowing chains or clips to be accommodated in the spaces between the pulleys; or large diameter pulleys may be used, of the hat or mushroom shape, often starred to provide recesses for chains and clips. Similar large pulleys direct the rope around curves. CF: undertub system Sinclair, 5 overturned Said of a fold, or the limb of a fold, that has tilted beyond the perpendicular. The sequence of strata thus appears reversed. Syn: inverted; inverted fold; reversed. AGI overturning skip A type of skip commonly used at metal mines, but not as often at coal mines, because of increased breakage. This skip consists of a rectangular receptacle for the material and a suspending frame of bail to an upper crosspiece of which is attached a suspension gear connecting the rope to the skip. Three guide shoes are generally provided at each side of the bail to keep it vertical. The skip body turns about a horizontal shaft at the lower end of the bail. Two rollers on the upper part are mounted on a shaft and cause the skip to tilt at an angle of 35 degrees at the tipping point in the headgear, where rollers run onto the curved guides. To prevent shocks in the case of an overwind the skips are fitted with overwind guides which glide along rollers fitted to the headgear above the tipping point. Sinclair, 5 2222

overventilation Too much air in the mine workings. Fay overvoltage The difference between the actual electrode potential, when appreciable electrolysis begins, and the reversible electrode potential. ASM, 1 overvoltage relay Relay that serves primarily the same purpose as an overcurrent relay except that it is connected in the line by a potential transformer which measures the voltage across the line. When an overvoltage exists the relay operates and opens the circuit breaker. Coal Age, 3 overwind a. To hoist a cage into or over the top of a headframe. Syn: overtravel Fay b. In hoisting through a mine shaft, failure to bring a cage or skip smoothly to rest at the proper unloading point at the surface. If severe, it can lead to a serious accident unless the special preventive devices function effectively. Overwind can also cause a cage to be lowered into the sump at the bottom of the shaft, also with serious consequences. Pryor, 3 overwinder One of the best known overwinder prevention devices consists of two vertical-screwed spindles, each carrying two traveling nuts and chain driven from the drum shaft so as to rotate in opposite directions. The nuts are prevented from rotating by projections engaging with a fixed plate and therefore travel up and down according to the movement of the cages. The upper nut takes care of overwinding and the lower nut of overspeeding. Mason overwinding a. A term applied to a continued pull on the hoisting rope of a cage, after the cage has reached the top of the shaft. The result of this carelessness, or accident, is a broken hoisting rope and all the danger that implies. Stauffer b. A rope or cable wound and attached so that it stretches from the top of a drum to the load. Nichols, 1 overwind switch A switch that may be used on winders, or haulages, to cause the power to cut off from the driving motor, or engine, and the brakes to be applied. Such a switch may be: (1) 2223

situated in the headgear and operated by the conveyance, (2) mounted on the automatic contrivance, or (3) operated by the depth or distance indicator. BS, 13 ovulite See: oolith Owen process A flotation process involving the violent agitation of the pulp in cold water to which a small percentage of eucalyptus oil, about 62.5 g, is added. Fay Owen's borehole surveying instrument A clockwork photographic apparatus that records clinometer and compass readings on sensitized paper. It is used during borehole surveying. Hammond Owen's jet dust counter An instrument similar to the konimeter but differing in that the air to be sampled undergoes humidification prior to being blown through the jet. The velocity of impingement is about 200 to 300 m/s and the jet is rectangular instead of circular. The prior humidification of the air causes condensation of moisture upon the dust particles by super saturation due to the pressure drop at the jet, and so assists in the deposition and retention of the particles on the slide. The Bausch and Lomb dust counter is the American counterpart of this instrument. Osborne oxacalcite See: whewellite oxalite See: humboldtine oxammite An orthorhombic mineral, (NH4 )2 C2 O4 .H2 O ; transparent; yellowish-white; forms lamellar and pulverent masses in guano. oxialyphite A variety of aliphite hydrocarbon containing oxygen; light-yellow; soft. Tomkeieff oxidate 2224

Sediment composed of the oxides and hydroxides of iron and manganese, crystallized from aqueous solution. It is one of Goldschmidt's groupings of sediments or analogues of differentiation stages in rock analysis. AGI oxidation a. The firing of a kiln in such a manner that combustion is complete and in consequence the burning gases are amply supplied with oxygen, which causes metals in clay and glazes to give their oxide colors. ACSG, 1 b. Combination with oxygen; increase in content of a molecular compound; increase in valency of the electropositive part of compound, or decrease in valency of the electronegative part. Pryor, 3 c. A reaction in which there is an increase in valence resulting from a loss of electrons. CF: reduction d. In fuel practice, the combination of oxygen with a substance, with or without the production of food. Francis, 2 oxidation of coal The absorption of oxygen from the air by coal, particularly in the crushed state; this engenders heat which can result in fire. Ventilation, while dispersing the heat generated, supports oxidation that increases rapidly with a rise in temperature. Fresh air should not gain access to the coal. See also: gob fire oxide A compound of oxygen with another element. CTD oxide discoloration Discoloration of a metal surface caused by oxidation during thermal treatment. Light Metal Age oxide mineral A mineral formed by the union of an element with oxygen; e.g., corundum, hematite, magnetite, and cassiterite. Leet, 1 oxide of iron An iron ore with oxygen as its main impurity; also iron rust. Mersereau, 2 oxidized deposit A deposit that has resulted from surficial oxidation. Bateman, 2 oxidized ore 2225

Metalliferous minerals altered by weathering and the action of surface waters, and converted, partly or wholly, into oxides, carbonates, or sulfates. These compounds are characteristic of metalliferous deposits at the surface and often to a considerable depth. See also: mixed ore Nelson oxidized zone The portion of an orebody near the surface that: (1) has been leached by percolating water carrying oxygen, carbon dioxide, or other gases; or (2) in which sulfide minerals have been partially dissolved and redeposited at depth, the residual portion changing to oxides, carbonates, and sulfates. CF: gossan; sulfide zone. Syn: zone of oxidation See also: supergene enrichment oxidizer A material that readily yields oxygen or other oxidizing substances needed for an explosive reaction to take place; solid oxidizers common in industrial explosives are ammonium nitrate and sodium nitrate. oxidizing flame In blowpiping, the outer, least visible, and less intense part of the flame, from which oxygen may be added to the compound being tested. See also: blowpiping oxidizing fusion An oxidation process used for fire refining bismuth, gold, and silver; the crude metals are melted down with oxidizing fluxes, so that the impurities are oxidized during the melting period and become part of the slag. Newton, 1 oxidizing smelting See: pyritic smelting oxonite An explosive prepared by dissolving picric acid in nitric acid. Fay oxyacetylene A mixture of oxygen, O2 , and acetylene gas, C2 H2 , in such proportions as to produce the hottest flame known for practical use. Oxyacetylene welding and cutting is used in almost every metalworking industry. Crispin oxyacetylene cutter 2226

An appliance for cutting metals by means of a flame obtained from acetylene and compressed oxygen, which are stored in separate steel cylinders. Oxyhydrogen and oxycoal gas flames are also used. Nelson oxychloride cement A plastic cement formed by mixing finely ground caustic magnesite with a solution of magnesium chloride. AGI oxygen A nonmetallic element, normally colorless, odorless, tasteless, nonflammable diatomic gas. Symbol, O. Occurs uncombined in the air to the extent of about 21% by volume and is combined in water, in most rocks and minerals, and in a great variety of organic compounds. Oxygen is very reactive and capable of combining with most elements. Essential for respiration in all plants and animals and for practically all combustion. Oxygen enrichment of steel blast furnaces accounts for the greatest use of the gas. Used in manufacturing ammonia, methanol, and ethylene oxide. Handbook of Chemistry and Physics, 3 oxygen balance The amount of oxygen in an explosive mixture, expressed in weight percent, liberated as a result of complete conversion of explosive material to CO2 , H2 O, SO2 , Al2 O3 , and other non-toxic gases; referred to as positive oxygen balance; negative oxygen balance is a deficient amount of oxygen leading to incomplete oxidation of explosive materials resulting in the possible formation of toxic gases, such as CO and NO. oxygen-Bessemer A steelmaking process in which the air blown through the bottom tuyeres is enriched with oxygen. If oxygen alone is used, tuyere wear is excessive. Oxygen plus steam or oxygen plus carbon dioxide can be used. Also called oxy-Thomas. See also: O oxygen consumption A person working hard requires about 10 ft3 /min (283 L/min) of air to supply adequate oxygen. Hammond oxygen deficiency See: anoxia oxygen-deficient atmosphere 2227

A concentration of oxygen in the atmosphere equal to or less than 19.5% by volume. OSHA oxygen-enriched atmosphere An atmosphere containing more than 23.5% oxygen by volume. OSHA oxygen-flash smelting process Employed as an autogeneous matte smelting process for smelting copper-nickel concentrate. Newton, 1 oxygen-free copper Electrolytic copper free from cuprous oxide; produced without the use of residual metallic or metalloidal deoxidizers. ASM, 1 oxygen impingement process A process used in steel making in which pure oxygen is blown down onto the bath in a converterlike vessel. Osborne oxygen index Volumetric ratio of oxygen to the total gases in a mixture. Van Dolah oxygen lance A device made up of a welding oxygen bottle and a length of rubber hose attached to a valve which is fitted to a steel pipe, so that when the tip of the lance is ignited it can be used to melt the solidified metal out of the iron tap hole in a blast furnace. oxygen process A process for making steel in which oxygen is blown upon or through molten pig iron, whereby most of the carbon and impurities are removed by oxidation. Harbison-Walker oxygen steel The use of oxygen instead of air to convert molten pig iron into steel. The oxygen is used in different ways in different furnaces, but the fastest ones utilize the direct oxidation effects of a relatively pure (99.5%) oxygen. See also: L oxyhornblende 2228

A hornblende with (OH+F+Cl) less than 1.0. Also called basaltic hornblende. Syn: lamprobolite oxyhydrogen Of, relating to, or utilizing a mixture of oxygen and hydrogen. Webster 3rd oxyhydrogen blowpipe A blowpipe in which hydrogen is burned in oxygen. Streams of the two gases in the proportion to form water are forced under pressure from separate reservoirs, and issue together from a jet, igniting just as they issue. The temperature produced which has been estimated at 5,000 degrees F (2,760 degrees C), is sufficient to fuse very refractory substances. Also called compound blowpipe. Standard, 2; Fay oxymagnite A former name for maghemite, isometric Fe2 O3 ; also called ferromagnetic ferric oxide. oxyphile See: lithophile ozarkite A white, massive variety of thomsonite, from Arkansas. Fay ozocerite A mineral paraffin wax, of dark yellow, brown, or black color with a melting point of 55 to 110 degrees C and sp gr, 0.85 to 0.95. Is soluble in gasoline, benzene, and turpentine and is found near the Caspian Sea region and in Utah as narrow seams in sandstone. Also called mineral wax; fossil wax; native paraffin; earth wax. Also spelled ozokerite. Syn: ader wax; earth wax; mineral fat. See also: fibrous wax CF: hatchettine; hatchettite. CTD ozone An allotropic, triatomic form of oxygen, O3 ; a faintly blue, irritating gas with a characteristic pungent odor, but at -112 degrees C it condenses to a blue magnetic liquid. It occurs in minute quantities in the air near the Earth's surface and in larger quantities in the stratosphere as a product of the action of ultraviolet light of short wavelengths on ordinary oxygen. Ozone is generated usually in dilute form by a silent electric discharge in oxygen or air. It decomposes to oxygen (as when heated) and it is a stronger oxidizing agent than oxygen. Used chiefly in disinfection and in deodorization (such as in water purification and in air conditioning), in oxidation and bleaching (such as in the treatment 2229

of industrial wastes), and in ozonolysis (such as in the manufacture of azelaic acid from oleic acid). Webster 3rd ozonizer Electrical apparatus that converts atmospheric oxygen to ozone; used in sterilizing water for drinking purposes and for purifying air. Pryor, 3

P pachnolite A monoclinic mineral, NaCaAlF6 .H2 O ; white; distinct cleavage; dimorphous with thomsenolite; an alteration of cryolite. Pachuca tank A cylindrical tank with a conical bottom. It contains a pipe that is coaxial with the leaching tank and open at both ends; compressed air is introduced at the lower end of this pipe, which behaves as an air lift. The density of the pulp within the pipe is less than that of the pulp surrounding it because of the column of air bubbles contained in the pipe, and the pressure of the denser pulp causes the pulp in the central pipe to rise and overflow, thus circulating the entire charge. Syn: Brown agitator; Brown tank. See also: Patterson agitator Newton, 1 Pacific suite One of two large groups of igneous rocks, characterized by calcic and calc-alkalic rocks. Harker (1909) divided all Tertiary and Holocene igneous rocks of the world into two main groups, the Atlantic suite and the Pacific suite. Because there is such a wide variation in tectonic environments and associated rock types in the areas of Harker's Atlantic and Pacific suites, the terms are now seldom used to indicate kindred rock types. CF: Mediterranean suite pacite An iron arsenosulfide near arsenopyrite in composition. pack a. A pillar, constructed from loose stones and dirt, built in the waste area or roadside to support the roof. See also: double packing; solid stowing; strip packing. Nelson b. A pack built on a longwall face between the gate-side packs is called an intermediate pack. 2230

SMRB c. Waste rock or timber support used for a roof over underground workings or used to fill excavations. Also called fill. Pryor, 3 d. To cause the speedy subsidence of ore in the process of washing by beating a keeve or tub with a hammer. pack builder a. Person who builds packs or pack walls. See also: pack b. In anthracite and bituminous coal mining, a worker who: (1) fills worked-out rooms, from which coal has been mined, with rock, slate, or other waste to prevent caving of walls and roofs; (2) builds rough walls and columns of loose stone, heavy boards, timber, or coal along haulageways and passageways and in rooms where coal is being mined, to prevent caving. Also called packer. See also: pillar man; timber packer; waller. DOT pack cavity system See: methane drainage pack drawer In anthracite and bituminous coal mining, a laborer who draws (tears down) stone or timber packs (pillars constructed by pack builders in the working place to support the roof during extraction of coal) to permit the roof to cave behind as the mining of the coal recedes toward the entrance of the working area. DOT packer a. A short expansible-retractable device deliberately set in a cased or uncased well bore to prevent upward or downward fluid movement; generally for temporary use. AGI b. A miner employed in stowing or packing the waste area. Also called gobber. Nelson packfong Chinese. A silver-white alloy of copper, zinc, and nickel; German silver. pack hardening Case carburizing, using a solid carburized medium, followed by a hardening treatment. CTD pack hole The space adjacent to a gate end at the face and between the face end of a gate-side pack and the coal face into which packs will be inserted when the gate is ripped or dinted. TIME 2231

packing a. Occurs in crushing plants when the material in the chamber is so compacted as to be nearly without voids. It occurs when free downward movement is inhibited. South Australia b. The filling of a waste area with stones and dirt. See also: solid stowing c. The method of giving support to a roof by the insertion of waste material placed or built into space from which coal or ore has been extracted. TIME d. The spacing or density pattern of the mineral grains in a rock. CF: fabric e. See: blocking f. With gyratories, packing copy refers to an accumulation of sticky fines on the diaphragm. South Australia packing density The bulk density of a granular material, when packed under specified conditions. It is commonly determined, particularly for foundry sands. packing factor Ratio of true volume to bulk volume. Van Vlack packing gland An explosion-proof entrance for conductors through the wall of an explosion-proof enclosure, to provide compressed packing completely surrounding the wire or cable, for not less than 1/2 in (1.27 cm) measured along the length of the cable. packsand A very fine-grained sandstone that is so loosely consolidated by a little calcareous cement as to be readily cut by a spade. AGI pack wall A dry-stone wall built along the side of a roadway, or in the waste area, of a coal or metal mine. The wall helps to support the roof and also to retain the packing material and prevent it spreading into the roadway. Nelson pad a. Ground-contact part of a crawler-type track. Nichols, 1 b. See: wallplate c. The refractory brickwork below the molten iron at the base of a blast furnace. Dodd paddle a. Numbered wooden marker which shovelers put in the cans of ore that they load. Hess b. A straight iron tool for stirring ore in a furnace. Standard, 2 c. A bat or pallet, as used 2232

in tempering clay. Standard, 2 d. A scoop for stirring and mixing, as used in glassmaking. Standard, 2 paddle conveyor See: paddle-type mixing conveyor paddle loader A belt loader equipped with chain-driven paddles that move loose material to the belt. Nichols, 1 paddle mixer A form of worm conveyor having two noncontinuous spirals that form paddles; the shafts are contrarotating and the spirals opposite. See also: paddle-type mixing conveyor paddle-type mixing conveyor A type of conveyor consisting of one or more parallel paddle conveyor screws. See also: blending conveyor; paddle conveyor. paddle washer A type of conveyor consisting of one or two inclined parallel paddle conveyor screws in a conveyor trough having a receiving tank and an overflow weir at the lower end and a discharge opening at the upper end. paddle-wheel fan A centrifugal fan with radial blades. Strock, 2 paddy A borehole drill bit having cutters that expand on pressure. Also called expansion bit; paddy bit. Long paddy bit See: paddy paddy lamp A portable battery-operated lamp attached to the front or rear of a personnel train. BS, 13 2233

padlock sheave a. The bucket sheave on a dipper or hoe shovel. Nichols, 1 b. A sheave set connecting inner and outer boom lines. Nichols, 1 page a. A small wooden wedge used in securing the timbering for excavations. Hammond b. In brickmaking, a track carrying the pallets bearing newly molded bricks. Standard, 2 pagodite Ordinary massive pinite in its amorphous compact texture and other physical characters, but containing more silica. The Chinese carve the soft stone into miniature pagodas and images. See also: agalmatolite; lardite; pinite. CTD Pahrump A provincial series of the Precambrian in California. paint a. A term used in the western United States for an earthy, pulverulent variety of cinnabar. b. A film of molybdenite in fractures and veinlets. paint gold A very thin coating of gold on minerals. painting The painting of the mine roof with a coal-tar paint that seals the bottom strata of the roof to prevent air from entering the crevices of the roof. Kentucky paint mill A machine for grinding mineral paints. Fay paint rock A soft, incompetent, fine-grained mass of quartz, pyrolusite, and kaolin with subangular fragments of chert, hematite, and goethite. Woodruff paint-rock ore 2234

See: natural ore pair A party of co-workers; a gang. Also spelled pare. Webster 2nd; Fay pair production The transformation of a high-energy gamma ray into a pair of particles (an electron and a positron) during its passage through matter. Lyman palagonite Devitrified basaltic glass. palasome The host rock or mineral in a replacement deposit. pale brick Brick that is underfired. Fay paleoa. A combining form denoting great age or remoteness in regard to time (Paleozoic), or involving ancient conditions (paleoclimate). Sometimes given as pale- (palevent). Also spelled: palaeo; palaio-. AGI b. A prefix indicating pre-Tertiary origin, and generally altered character, of a rock to the name of which it is added, such as paleopicrite; by some the prefix has been applied to pre-Carboniferous rocks or features, such as the PaleoAtlantic Ocean. AGI paleobotany The study of plants of past geological ages through the investigation of fossils. CF: paleontology; palynology. paleoclimatology The branch of science that treats of climatological conditions during the history of the Earth. paleocurrent

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A current, generally of water, that influenced sedimentation or other processes or conditions in the geologic past. paleoecology The science of the relationship between ancient organisms and their environments. AGI paleogeography a. The study and description of the physical geography of the geologic past, such as the historical reconstruction of the pattern of the Earth's surface or of a given area at a particular time in the geologic past, or the study of the successive changes of surface relief during geologic time. b. The study of the relative positions of land masses as part of tectonic reconstructions of Earth history. paleogeologic map A map that shows the areal geology of an ancient surface at some time in the geologic past; esp. such a map of the surface immediately below an unconformity, showing the geology as it existed at the time the surface of unconformity was completed but before the overlapping strata were deposited. Paleogeologic maps were introduced by Levorsen (1933). AGI paleolithologic map A paleogeologic map that shows lithologic variations at some buried horizon or within some restricted zone at a particular time in the geologic past. AGI paleomagnetism Faint magnetic polarization of rocks that may have been preserved since the accumulation of sediment or the solidification of magma whose magnetic particles were oriented with respect to the Earth's magnetic field as it existed at that time and place. AGI paleontological facies a. The paleontological aspect of a particular sedimentary lithology; e.g., nummulitic facies, crinoid facies, etc. Schieferdecker b. Sedimentary facies differentiated on the basis of fossils. AGI paleontologist Person who studies the fossilized remains of animals and/or plants. AGI 2236

paleontology A science that deals with the life of past geological periods, based on the study of fossil remains of plants and animals, and gives information esp. about the phylogeny and relationships of modern animals and plants and about the chronology of the history of the Earth. CF: paleobotany; paleoclimatology; paleogeography. Webster 3rd paleozoology That branch of paleontology dealing with the study of fossil animals, both invertebrate and vertebrate. AGI palimpsest Said of a structure or texture of metamorphic rocks in which remnants of some preexisting structure or texture are preserved. palingenesis Formation of a new magma by the melting of pre-existing magmatic rock in situ. Considered incorrectly by some workers as a syn. of anatexis. Adj: palingenic. AGI palladinite A poorly defined ocherous coating on palladian gold, probably PdO. palladium A soft, ductile, steel-white metallic element of the platinum group metals. Symbol, Pd. Found along with platinum and other metals of the platinum group in placer deposits; also found associated with nickel-copper deposits. Used as a catalyst, in dentistry, watchmaking, surgical instruments, and electrical contacts. Handbook of Chemistry and Physics, 3 palladium amalgam A former name for potarite. See also: potarite palladium gold Same as porpezite, or gold, containing palladium up to 10%. See also porpezite; gold. Fay pallas iron 2237

See: pallasite pallasite a. Any ultramafic rock, whether of meteoric or terrestrial origin, that contains approx. 60% iron if meteoric, or more iron oxides than silica if terrestrial. AGI b. A stony-iron meteorite composed essentially of large single glassy crystals of olivine embedded in a network of nickel-iron. Pallasites are believed to have been formed at the interface of the stony mantle and metal core of a layered planetoid. Syn: pallas iron palleting A light platform in the bottom of powder magazines to preserve the powder from dampness. Fay pallet molding A method of forming bricks in sanded molds, from which they are dumped on a board called a pallet. Standard, 2 pallet-type conveyor A series of flat or shaped wheelless carriers propelled by and attached to one or more endless chains or other linkage. Palo-Travis analyser A sedimentation apparatus for determining particle size, based upon the settling of powder through a long sedimentation tube filled with liquid. The instrument consists of the sedimentation tube, a smaller reservoir at the top joined to the tube through a large bore stopcock, and a calibrated capillary mounted concentrically at the bottom of the tube. Osborne paludal Pertaining to swamps or marshes, and to organic, clay, or other material deposited in a swamp environment. CF: palustrine paludification Process of formation of a peat bog. This requires a steady growth of new peat-forming plants in phase with a steady general sinking of the depression in which this occurs. Pryor, 3 palustrine 2238

Pertaining to material deposited in a swamp or marsh environment. CF: paludal palygorskite a. A monoclinic and orthorhombic mineral, (OH)2 (Mg,Al)4 (Si,Al)8 O20 .8H2 O ; fibrous; in desert soils. b. A general name for lightweight fibrous clay minerals showing significant substitution of aluminum for magnesium; characterized by distinctive rodlike shapes under an electron microscope. Syn: attapulgite palynology a. A branch of science concerned with the study of pollen of seed plants and spores of other embryophytic plants, whether living or fossil, including their dispersal and applications in stratigraphy and paleoecology. AGI b. The study of the fossilized spores and pollen grains of the plants, esp. those whose remains contributed to the formation of coal seams. CF: paleobotany; paleontology. Nelson pan a. A shallow steel or porcelain dish in which drillers or samplers wash drill sludge to a gravity concentrate and separate the particles of heavy minerals from the lighter-density rock powder to ascertain if the rocks traversed by the borehole contain minerals of value. Syn: tin dish Long b. Hardpan. c. Fireclay or underclay of coal seams. d. A trough or section of a pan conveyor or shaker conveyor. Nelson e. The framework of a belt or chain conveyor. See also: tray Mason f. A circular steel dish from 10 to 16 in (25 to 40 cm) in diameter at the top, from 2 to 2-1/2 in (5.1 to 6.4 cm) deep, and with sides sloping at 35 degrees to 40 degrees to the horizontal, used for testing and working placer deposits. Syn: batea; miner's pan; prospecting pan; gold pan. CF: dish g. A carrying scraper. Nichols, 1 h. See: panning panabase See: tetrahedrite panabasite A former name for tetrahedrite. See also: tetrahedrite pan amalgamation See pan-amalgamation process. pan-amalgamation process

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Method of recovering silver and gold from their ores, in which a cast iron pan or barrel is used for contacting a slurry of the crushed ore with salt, copper sulfate, and mercury; the released silver and gold form an amalgam with the mercury. Syn: pan amalgamation Pan-American jig Mineral jig developed for treatment of alluvial sands. Pryor, 3 pancake a. See: ribbon b. Any of concrete discs that are stacked to form concrete columns for stope support. They are cast at the surface and are usually 30 in (76.2 cm) diameter by 4 in (10.2 cm) thick with reinforcement from wire rope. Higham panclastite An explosive composed of liquid nitrogen tetroxide mixed with carbon disulfide or other liquid combustible, in the proportion of three volumes of the former to two of the combustible. Fay pan conveyor a. A conveyor comprising one or more endless chains or other linkage to which usually overlapping or interlocking pans are attached to form a series of shallow, open-topped containers. Some pan conveyors have been known also as apron conveyors. b. Jigging conveyor; a trough down which coal slides after mining and loading in dipping seams, with motion being aided by a shaking action. See also: jigger c. A trough conveyor or gravity conveyor. Nelson pandermite a. See: priceite b. A name for firm, compact, porcelainlike masses of colemanite. pan-edge a. A runner mill for grinding or mixing granular material. b. Steel supporting plates on which furnace bottom refractories are placed. panel a. A large rectangular block or pillar of coal. b. A method of working whereby the workings of a mine are divided into sections, each surrounded by solid strata and coal with only necessary roads through the coal barrier. Also spelled pannel. Mason c. The working of coal seams in separate panels or districts; e.g., single unit panel. See also: panel working d. Rectangle of lode ore that is defined by means of levels and winzes and 2240

then considered to be proved as regards volume for valuation purposes. Pryor, 3 e. A group of breasts or rooms separated from the other workings by large pillars. Fay f. A small portion of coal left uncut. Webster 3rd panel barrier The pillar of coal left between the adjacent panels. These pillars are often worked on the retreat after the coal in the panels has been extracted. In the panel system of bord-andpillar mining, the panel barrier may be 22 yd (20 m) (minimum) wide and about 300 yd (274 m) apart. In longwall panel mining, the barriers may be made of sufficient width for extraction by a conveyor face on the retreat. Also called panel pillar. See also: Bolsover experiment panel slicing a. In stoping, the process of mining out a panel either from above, below, or one side as described by a qualifying term. Pryor, 3 b. See: top slicing and cover caving panel working a. Working laid out in districts or panels, which are then extracted as single units. The panel system of working may be adopted with pillar-and-stall and longwall methods. See also: pillar methods of working b. A system of working coal seams in which the colliery is divided up into large squares or panels isolated or surrounded by solid ribs of coal of which a separate set of breasts and pillars is worked, and the ventilation is kept distinct; i.e., every panel has its own circulation, the air of one not passing into the adjoining one, but being carried direct to the main return airway. Zern pan feeder See: conveyor-type feeder pan-feeder operator See: mill feeder panhead A head to a rivet or screw having the shape of a truncated cone. Hammond panidiomorphic A textural term for rocks in which all or almost all of the mineral constituents are idiomorphic or euhedral. 2241

panman a. A worker who places in position and tends the operation of underground trough conveyors for the transportation of coal or other minerals. These conveyors are built in sections, and the principal task of the panman is to move the sections from one position to another. Hess b. One engaged in dismantling or building conveyors. Also called panner. Mason panning A technique of prospecting for heavy metals, such as gold, by washing placer or crushed vein material in a pan. The lighter fractions are washed away, leaving the heavy metals behind in the pan. See also: pan AGI pantellerite A peralkaline rhyolite or quartz trachyte with normative quartz exceeding 10%. It is more mafic than comendite. AGI pantograph a. A type of drawing instrument consisting of rods linked together in the form of a parallelogram, used for copying a drawing to any required scale. Hammond b. The hinged diamond-shaped structure mounted on the roof of an electric locomotive to collect electric power from an overhead wire. Hammond pan-type car Doorless car of two-way, side-dump design; built in capacities from 4 to 10 yd3 (3.1 to 7.6 m3 ). The car body is reversible and may be dumped to either side. Dumping is accomplished by means of an external hoist at the dumping point. Pit and Quarry Panzer conveyor See: armored flexible conveyor Panzer-Forderer snaking conveyor A very strong, armored conveyor that is moved forward behind a coal plow by means of a traveling wedge pulled along by the plow or by means of jacks or compressed-airoperated rams attached at intervals to the conveyor structure. Sinclair, 5 papa

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a. A bluish white, massive New Zealand clay like pipe clay; used for whitening fireplaces. When hard, it is called papa rock. Etymol: Polynesian. b. Sp. A nugget of gold or silver. c. A nodule of mineral. papagoite A monoclinic mineral, CaCuAlSi2 O6 (OH)3 ; forms blue crystals; secondary; at Ajo, Pima County, AZ. paper clay A fine-grained, white, kaolinic clay with high retention and suspending properties, high reflectance, and a very low content of free silica. It is used for coating or filling paper. AGI paper coal a. Coal in which cuticular matter may be prominent. AGI b. A variety of brown coal deposited in thin layers like sheets of paper. Fay paper shale A shale that easily separates on weathering into thin layers or laminae suggesting sheets of paper; it is often highly carbonaceous. AGI paper spar A crystallized variety of calcite found in thin lamellae or paperlike plates. Standard, 2 parSee: paraparaa. A prefix applied to the names of metamorpic rocks that have been derived from sediments; e.g., paragneiss. Stokes b. Prefix meaning beside or nearby. c. Indicating a polymorph. d. Indicating a schist or gneiss derived from a sedimentary protolith. e. A matrix-rich clastic sedimentary rock. f. In chemistry, a prefix indicating: (1) an isomeric or polymeric modification; such as paracyanogen, paraldehyde, etc.; (2) a modification or a similar compound that is not necessarily isomeric or polymeric; such as, paramorphine; (3) a benzene diderivative in which the substituted atoms or radicals are directly opposite each other on the benzene ring--i.e., occupying the positions 1 and 4-such as paraxylene; or (4) an inactive isomer produced by a combination of its dextroand levo- modifications--such as, paratartaric acid. A Greek prefix meaning beside. 2243

Abbrev., p-. Syn: par- g. A Greek prefix meaning beside. In the name of a metamorphic rock, such as paragneiss, it means derived from an original sediment. Webster 3rd parabola The shape taken by the curve of a bending moment diagram for a uniformly distributed load on a beam simply supported. Hammond parabutlerite An orthorhombic mineral, Fe3+ (SO4 )(OH).2H2 O ; dimorphous with butlerite: orange; an alteration product of copiapite. paracelsian A monoclinic mineral, BaAl2 Si2 O8 ; feldspar group; pale yellow; dimorphous with celsian; at Candoglia, Italy. Syn: barium feldspar parachrosis Discoloration in minerals from exposure to weather. Standard, 2 paraconformity An unconformity at which strata are parallel and the contact is a simple bedding plane. AGI paraconglomerate A term proposed by Pettijohn (1957) for a conglomerate that is not a product of normal aqueous flow, but is deposited by such agents as subaqueous turbidity slides and glacier ice; it contains more matrix than gravel-sized fragments (pebbles may form less than 10% of the rock). Examples include tillites, pebbly mudstones, and relatively structureless clay or shale bodies in which pebbles or cobbles are randomly distributed. Syn: conglomerate mudstone paracoquimbite A trigonal mineral, Fe3+2 (SO4 )3 .9H2 O ; dimorphous with coquimbite; pale violet; astringent tasting; secondary; in oxidized iron sulfide deposits. paradamite

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A triclinic mineral, Zn2 (AsO4 )(OH) ; rare; dimorphous with adamite and isomorphous with tarbuttite; transparent; vitreous; pale yellow; forms sheaflike aggregates and striated equant crystals; at the Ojuela Mine, Durango, Mexico. paraffin shale See: oil shale paragenesis A characteristic association or occurrence of minerals or mineral assemblages in ore deposits, connoting contemporaneous formation. CF: mineral sequence paragenetic a. Pertaining to paragenesis. AGI b. Pertaining to the genetic relations of sediments in laterally continuous and equivalent facies. AGI paragneiss In petrology, a gneiss formed by the metamorphism of a sedimentary rock. CF: orthogneiss Paragon Trade name for a nonrotating rope of 12 by 6 over 3 by 24 strand construction. Hammond paragonite A monoclinic mineral, NaAl2 (AlSi3 )O10 (OH)2; mica group; pseudohexagonal with basal cleavage; forms fine-grained, massive, scaly aggregates; occurs in metamorphic rocks and in soils; not common as it is incompatible with potassium feldspar (albite plus muscovite is more stable); rarely identified because of its similarity to muscovite. Syn: soda mica paragonite schist A variety of schist in which paragonite supplants muscovite or biotite. paraguanajuatite A trigonal mineral, Bi2 (Se,S)3 ; paramorphous after orthorhombic guanajuatite. parahilgardite 2245

A mineral trimorphous with monoclinic hilgardite and triclinic hilgardite. See also: hilgardite parahopeite A colorless hydrous zinc phosphate, Zn3 (PO4 )2 .4H2 O , triclinic. Minute tabular or prismatic crystals; fan-shaped aggregates. From Broken Hill, Northern Rhodesia; Salmo, BC. English parajamesonite An orthorhombic mineral, Pb4 FeSb6 S14 ; dimorphous with jamesonite; metallic; black; distinguished by its X-ray pattern. paralaurionite A monoclinic mineral, PbCl(OH); dimorphous with laurionite; soft; forms white pseudoorthorhombic prismatic crystals; a secondary mineral in lead deposits. paralic Said of deposits laid down on the landward side of a coast, in shallow fresh water subject to marine invasions. Thus, marine and nonmarine sediments are interbedded; as exemplified in the lower part of the Coal Measures, the nonmarine (paralic) predominate, with relatively thin marine bands. CF: limnic paralic coal basin A coal basin that originated near the sea--as opposed to a limnic coal basin. AGI parallax a. In survey work, incorrect reading of a graduation on an instrument if the observer's eye is not truly normal to the graduated plate. Pryor, 3 b. The change in bearing or apparent position of an object produced by a change in the observer's position. NCB c. The apparent displacement, or change in position, of the crosshairs of a focusing telescope with reference to the image of an object, as the eye is moved from side to side, when the focus of the eyepiece or objective is imperfect. Seelye, 2 parallel blasting circuit An electric blasting circuit in which the leg wires of each detonator are connected across the firing line directly or in parallel through bus wires. Syn: series-in-parallel circuit Atlas 2246

parallel circuit firing A method of connecting together a number of detonators that are to be fired electrically in one blast. The electric detonators are connected to two common points. Each detonator offers a path for the electric current, independent of all the other detonators in the circuit, and therefore calls for a higher amperage than a series circuit in which there is but one path. Nelson parallel cut Group of parallel holes, not all charged with explosive, that creates the initial cavity to which the loaded holes break in blasting a development round. Pryor, 3 parallel displacement fault A fault along which all straight lines on opposite sides of the fault and outside the dislocated zone that were parallel before the displacement are parallel afterward. AGI parallel drum A cylindrical form of drum on which the haulage or winding rope is coiled. The drum roll may be plain or grooved. For deep winds, multilayering of rope is often used to reduce the drum size required. Also, for deep winding (3,000 ft or 915 m or more), a balance rope is almost essential with a parallel drum. Syn: cylindrical drum Nelson parallel duplex mine cable See: portable parallel duplex mine cable parallel entry Usually an intake airway parallel to the haulageway. USBM, 1 parallel extinction In mineral optics, refers to crystal edges or cleavage traces parallel to the optic directions of the mineral. CF: extinction parallel firing The firing of detonators in a round of shots by dividing the total supply current between the individual detonators. CF: series firing BS, 12 parallel flow 2247

Flow in the same direction of two or more streams within a stream system. parallel fold A fold in which beds maintain the same thicknesses throughout. CF: similar fold; supratenuous fold. Syn: concentric fold parallel growth Two or more crystals with corresponding faces parallel. Fay parallel lines Lines that lie in the same plane and are equally distant from each other at all points. The term is ordinarily applied to straight lines. Jones, 2 parallelogram Quadrilateral that has opposite sides parallel and opposite angles equal. Jones, 2 parallel ripple mark A ripple mark with a relatively straight crest and an asymmetric profile; specif. a current ripple mark. AGI parallel series Two or more series of electric blasting caps arranged in parallel. See also: multiple series parallel series circuit A method of connecting together a number of detonators to be fired electrically in one blast. The circuit consists of a number of series circuits connected in parallel. Syn: series-in-parallel circuit Nelson parallel unconformity See: disconformity parallel wire method An electrical prospecting method using equipotential lines or curves in prospecting for orebodies. In the parallel wire method, two bare copper wires about 3,000 ft (915 m) long, placed about 2,000 ft (610 m) or more apart, are used as electrodes. Current is supplied from the generator, and the electrodes are connected to the ground at 100 ft (30 2248

m) intervals by iron grounding pins. Equipotential lines are located by two electrodes or wooden rods, to one end of which are fastened metal spikes about 6 to 7 in (15 to 18 cm) long. The electrodes are connected by some 150 ft (46 m) of wire that runs down the rods to the spikes. If a head telephone is placed in the circuit, the absence of sound in the telephone indicates that the two electrodes are at the same potential. By this method, the equipotential lines can be traced. Lewis paramagnetic Having a small positive magnetic susceptibility. A paramagnetic mineral such as olivine, pyroxene, or biotite contains magnetic ions that tend to align along an applied magnetic field but do not have a spontaneous magnetic order. CF: diamagnetic paramagnetism a. The magnetism of a paramagnetic substance. The property by which the north pole of a magnet that is magnetized by induction is repelled to 180 degrees by the north pole of the inducing magnet. Standard, 2 b. The property possessed by a substance of producing a higher concentration of magnetic lines of force within itself than in the surrounding magnetic field when it is placed in such a field. Miall c. A property of many substances, related to ferromagnetism, by virtue of which, when placed in a nonuniform magnetic field, they tend to move toward the strongest part. Permanent magnetism is practically absent and the susceptibility, which is much less than that of iron, is constant at any given temperature, but in most substances it is nearly inversely proportional to the absolute temperature. CF: ferrimagnetism; diamagnetism. Holmes, 1 paramelaconite A tetragonal mineral, Cu+2 Cu2+2 O3 ; purplish black; at Bisbee, AZ. parameter a. A constant or variable in a mathematical expression that distinguishes various specific situations. b. In crystallography, one of the three non-coplanar vectors which describe a lattice. Syn: lattice parameter paramontroseite An orthorhombic mineral, VO2 ; forms by loss of hydrogen and iron from montroseite in an initial stage of oxidation of uranium-vanadium deposits. paramorph A pseudomorph with the same composition as the original crystal, caused by a phase transformation; e.g., calcite with aragonite morphology. CF: pseudomorph 2249

paramorphism a. The alteration of one mineral into another without change of composition, such as augite into hornblende in uralitization. Fay b. With metamorphism, it describes such thorough changes in a rock that its old components are destroyed and new ones are built up. See also: allomorphism paramoudra Large flint nodule. See also: potstone pararammelsbergite An orthorhombic mineral, NiAs2 ; loellingite group; trimorphous with rammelsbergite and krutovite; metallic tin-white; commonly massive. pararealgar A monoclinic mineral, AsS ; trimorphous with realgar and alpha-AsS; powdery; bright yellow to orange-brown; easily mistaken for orpiment. paraschist A schist derived from a sedimentary rock. See also: orthoschist; schist. paraschoepite An orthorhombic mineral, UO3 .(2-x)H2 O ; bright yellow; a dehydration product of schoepite. Formerly called schoepite III. See also: schoepite parasymplesite A monoclinic mineral, Fe2+3 (AsO4 )2 .8H2 O ; vivianite group; dimorphous with symplesite and isomorphous with koettigite; bluish green. paratacamite A trigonal mineral, Cu2 (OH)3 Cl ; forms twinned rhombohedra; massive or powdery; green to green-black; a secondary mineral in copper deposits. paratellurite A tetragonal mineral, TeO2 ; rutile group; soft; waxy; gray-white; dimorphous with tellurite; at Cananea, Mexico. 2250

paratomous Having planes of cleavage inclined to the axis; also, abounding with facets of cleavage. Standard, 2 parautochthonous granite A mobilized portion of an autochthonous granite that has moved higher in the crust or, more usually, into tectonic domains of lower pressure. It shows variable marginal relations, in some places migmatitic in others characterized by a thermal aureole. Schieferdecker paravauxite A triclinic mineral, FeAl2(PO4 )2(OH)2.8H2O ; colorless; forms small prismatic crystals; at Llallagua, Bolivia. parbigite See: messelite pargasite A monoclinic mineral, NaCa2 (Mg,Fe)4 Al(Si6 Al2 )O22 (OH)2 ; amphibole group; prismatic cleavage; occurs in dolomitic marbles and in skarns. Parian marble One of the most famous of ancient statuary marbles; from the island of Paros, Greece. parisite A trigonal mineral, 6[(Ce,La,Nd)2 CaCO3 )3 F2 ] ; vitreous to resinous; forms acute hexagonal bipyramids; in veins, such as the emerald deposits of Columbia; also in alkalic pegmatites. Named for J.J. Paris. parkerite A monoclinic mineral, Ni3 (Bi,Pb)2 S2 ; metallic; bronze; has three cleavages; in a magmatic sulfide deposit, Insizwa, South Africa. Parkerizing Treatment of steel in hot aqueous solution of free phosphoric acid and manganese dihydrogen phosphate, other salts sometimes being used as accelerators. A fine-grained 2251

insoluble film of ferric phosphate is formed in a few minutes, which is corrosion resistant. Pryor, 3 Parker process A method for producing low-temperature coke in which each retort is a monobloc iron casting 9 ft (2.7 m) high, containing 12 tubes, which taper from 4-1/2 in (11.4 cm) at the top to 5-1/4 in (13.3 cm) at the bottom. A battery contains 36 retorts in 2 rows of 18. Retorts and combustion chambers are arranged alternately, so that each retort is located in a radiation chamber formed by the walls of adjacent combustion chambers. The retorts are heated only by radiation from these walls, so that there is no overheating and the inside temperature of the retorts can be maintained accurately at 1,112 degrees F (600 degrees C). A cooling chamber is fitted below each pair of retorts, of a size sufficient to hold the coke from both. The pairs of retorts are charged and discharged every 4 h. Syn: Coalite process Parkes process A process used to recover precious metals from lead. It is based on the principle that if 1% to 2% of zinc is stirred into molten lead, a compound of zinc with gold and silver separates out and can be skimmed off. ASM, 1 parmalee wrench A wrench that has a smooth segmented sleeve that when tightly clamped around the tube of a core barrel, will not mar or distort the thin tube when the core barrel is taken apart. Long parral agitator An agitator using a number of small airlifts disposed about a circular, flat-bottomed tank in such a way as to impart a circular swirling motion to the pulp. Liddell Parr formula The simplest method for determining the amount of mineral matter present in a coal is to determine the ash and sulfur contents and to make corrections for the changes taking place in these during combustion. The Parr formula for doing this is: total inorganic matter=moisture+1.08 ash+0.55 sulfur, where moisture, ash, and sulfur represent the percentages of these substances found by analysis of the coal. Francis, 1 Parrish arm Long arm made of a flexible board for the suspension of a shaker screen. Zern 2252

Parrish shaker A screening shaker with flexible wooden hangers and flexible drive arms; used for sizing anthracite. Mitchell Parr's classification of coal A classification system based on the proximate analysis and calorific value of ash-free, dry coal. The heating value of raw coal is obtained, and from these data a table is drawn up, at one end of which are the celluloses and woods of about 7,000 Btu/lb (16.3 MJ/kg). These data are then plotted against the percentage volatile matter in unit coal. Hess parsonsite A triclinic mineral, Pb2 (UO2 )(PO4 )2 .2H2 O ; forms pale citron-yellow crusts, powders, and tiny laths; nonfluorescent; radioactive; a secondary mineral in uraniferous pegmatites and other uranium deposits. part In founding, a section of a mold or flask specif. distinguished (in a three-part flask) as top part, middle part, and bottom part. Standard, 2 part 90 miner A miner employed at an underground coal mine or at a surface work area of an underground coal mine who has exercised the option under the old section 203b program (36 FR 20601, October 27, 1971), or under 90.3 (Part 90 option; notice of eligibility; exercise of option) of this part to work in an area of a mine where the average concentration of respirable dust in the mine atmosphere during each shift to which that miner is exposed is continuously maintained at or below 1.0 mg/m3 of air, and who has not waived these rights. CFR, 1 part-face blast Either of two stages of blasts when the height of the rock face is too great to blast in one operation. McAdam, 2 partially fixed An end support to a beam or a column that cannot develop the full fixing moment. Hammond partial melting 2253

a. Melting of part of a rock; because a rock is composed of different minerals, each with its own melting behavior, melting does not take place at one temperature (as for ice at 0 degrees C) but takes place over a range of temperatures; melting starts at the solidus temperature and continues, nonlinearly, as the temperature increases to the liquidus temperature when the rock is totally molten. Fowler b. A situation in which only certain minerals in a rock are melted, due to their lower melting temperature. partial pressure a. That part of the total pressure of a mixture of gases contributed by one of the constituents. Strock, 2 b. See: Dalton's law partial pyritic smelting Blast furnace smelting of copper ores in which some of the heat is provided by oxidation of iron sulfide and some by combustion of coke. See also: pyritic smelting partial roasting Roasting carried out to eliminate some but not all of the sulfur in an ore. CTD partial subsidence Any amount of subsidence that is less than full subsidence; such as with solid or strip packing. Nelson particle A general term, used without restriction as to shape, composition, or internal structure, for a separable or distinct unit in a rock; e.g., a sediment particle, such as a fragment or a grain, usually consisting of a mineral. AGI particle diameter The length of a straight line through the center of a sedimentary particle considered as a sphere; a common expression of particle size. See also: particle size particle mean size See: particle size particle size The general dimensions (such as average diameter or volume) of the particles in a sediment or rock, or of the grains of a particular mineral that make up a sediment or 2254

rock, based on the premise that the particles are spheres or that the measurements made can be expressed as diameters of equivalent spheres. It is commonly measured by sieving, by calculating settling velocities, or by determining areas of microscopic images. See also: particle diameter particle-size analysis Determination of the statistical proportions or distribution of particles of defined size fractions of a soil, sediment, or rock; specif. mechanical analysis. Syn: size analysis particle-size distribution The percentage, usually by weight and sometimes by number or count, of particles in each size fraction into which a powdered sample of a soil, sediment, or rock has been classified--such as the percentage of sand retained on each sieve in a given size range. It is the result of a particle-size analysis. Syn: size distribution; size-frequency distribution. AGI particle-size reduction The process of crushing or grinding material to reduce the particle size. BS, 2 particle sorting Separation of solid particles, in a fluid (air, water, etc.), because of different densities or masses. Bennett particle velocity A measure of the intensity of ground vibration generated from a blasting event, specif. the time rate of change of the amplitude of ground displacement, given in inches (or millimeters) per second. particulate Refers to particles collected by filtration from ambient air. SME, 1 parting a. A lamina or very thin sedimentary layer separating thicker strata of a different type; e.g., a thin layer of shale or slate in a coal bed, or a shale break in sandstone. Strata tend to separate readily at partings. CF: band b. A small joint in coal or rock, or a layer of rock in a coal seam. See also: back c. The physical property of some specimens of mineral species to break along specific crystallographic planes because of twinning or chemical alteration along them; e.g., rhombohedral parting in corundum. CF: cleavage; 2255

fracture. Syn: mineral parting d. Cutting simultaneously along two parallel lines or along two lines which balance each other in the matter of side thrust. e. The final process after cupellation to remove the silver from bullion bead. f. A side track or turnout in a haulage road on which empty or loaded cars are collected for distribution to points for loading or for haulage to the surface or to the shaft or slope bottom for hoisting. parting and connection man In bituminous coal mining, a laborer who directs the movement of mine cars from a parting (a side track). Also called connection man; parting boy. See also: parting parting boy See: parting and connection man parting cleaner In bituminous coal mining, one who only picks out seam partings (layers of rock) in the coal working face prior to blasting, using a long-handled pick. DOT parting density Density maintained in the bath in dense media separation. Pryor, 4 parting flask A flask used to separate gold and silver, such as by quartation, in assaying procedures. Syn: parting glass parting glass See: parting flask parting liquid Any of several liquids--such as tetrabromethane, ethylene dibromide, pentachlorethane, and trichlorethylene--that are used in the DuPont mineral separation process. See also: DuPont process parting powder A powder made from chalk, bone meal, or similar nonsiliceous material, suitably waterproofed, which is applied to a pattern to ensure a clean strip from the molding sand. Osborne 2256

parting slate A term applied to a thin layer of slate between two seams of coal. Fay partition curve A curve indicating, for each specific gravity (or size) fraction, the percentage that is contained in one of the products of the separation; e.g., the reject. Syn: distribution curve partition density The density corresponding to 50% recovery as read from a partition curve. Syn: tromp cut point partition factor The percentage of a specific gravity (or size) fraction recovered in one of the products of the separation; e.g., the reject. Syn: distribution factor partitioning method A resistivity method in which a special electrode configuration is used, consisting of five electrodes, instead of the usual number of four, to provide a check on the observations. Schieferdecker partition size The separation size corresponding to 50% recovery as read from a size partition curve. BS, 5 partly filled stope See: square-set stoping parts of line Separate strands of the same rope or cable used to connect two sets of sheaves. Nichols, 1 part-swing shovel A power shovel in which the upper works can rotate through only part of a circle. Nichols, 1 party chief 2257

In seismic prospecting, the person who supervises the personnel of the crew and generally is in charge of interpretation of the data. Dobrin party foreman In seismic prospecting, the person who supervises the work of a field party. Subordinate to a nonresident party chief who is responsible for the interpretation of the data. AGI party manager a. In seismic prospecting, this person's function is to handle the operational phases of the work, particularly those involving logistics and access in difficult or remote areas, giving the party chief more time for interpretation of the data. Dobrin b. In gravity and magnetic prospecting, the person in charge of the operations of a field party. AGI Pasadenian orogeny Mid-Pleistocene diastrophism. AGI Pascal's law The component of the pressure in a fluid in equilbrium that is due to forces externally applied is uniform throughout the fluid. Webster 3rd pascoite A monoclinic mineral, Ca3 V10 O28 .17H2 O ; forms yellow-orange to dark red-orange crusts and tiny laths; a secondary vanadium mineral in uranium-vanadium deposits of the Colorado Plateau, and at Minasragra, Peru. pass a. An inclined opening in a mine, a raise or a winze, through which coal or ore is delivered from a higher to a lower level. At the lower end, the pass is normally provided with a chute or hydraulic gate through which the material is discharged into cars or trams. See also: chute Nelson b. A raise or winze for workers to travel in from one level to another. Zern c. The running of a sample through a sample divider. d. In surface mining, a complete excavator cycle in removing overburden. BCI passage a. A cavern opening or underground tunnel having greater length than height or width; large enough for human entrance and larger by comparison than a lead. AGI b. See: pass passby 2258

a. The double-track part of any single-track system of transport. Mason b. A siding in which cars pass one another underground; a turnout. Zern passing boss See: motor boss passing point a. On haulage roads, the point at which the loaded trams going outby pass the empty trams going inby. Nelson b. In shafts, the point at which the loaded ascending cage or skip passes the empty descending cage or skip. Nelson passing track A sidetrack with switches at both ends. Kentucky passivation The changing of the chemically active surface of a metal to a much less reactive state. CF: activation passivator A type of inhibitor that changes the electrode potential of a metal, causing it to become more cathodic or electropositive. passive coefficient of earth pressure The maximum ratio of the major principal stress to the minor principal stress. This is applicable where the soil has been compressed sufficiently to develop an upper limiting value of the major principal stress. ASCE passive earth pressure The maximum value of lateral earth pressure exerted by soil on a structure, occurring when the soil is compressed laterally, causing its internal shearing resistance along a potential failure surface to be completely mobilized; the maximum resistance of a vertical earth face to deformation by a horizontal force. CF: active earth pressure AGI passive fault Fault not liable to further movement. CF: active fault Carson, 2 passive metal 2259

A metal on which an oxide film that prevents further attack on the metal is readily formed. When a metal other than a noble metal has a high resistance to corrosion, it is because of passivity; e.g., chromium, nickel aluminum, tin, and various alloys. See also: passivity CTD passive state of plastic equilibrium Plastic equilibrium obtained by a compression of a mass. ASCE passive transducer A transducer whose output waves are independent of any sources of power controlled by the actuating waves. Hy passivity a. A metal that is normally active according to its position in the electromotive-force series is said to be passive whenever its electrochemical behavior is that of a less active metal. b. A metal is passive when it is relatively resistant to corrosion in an environment in which a large decrease in free energy is associated with the corrosion reaction. c. A condition in which a piece of metal, because of an impervious covering of oxide or other compound, has a potential much more positive than the metal in the active state. ASM, 1 pass pipe An iron pipe connecting the water at the back of one set of tubbing with that of another, or a pipe only in communication with one tub and open to the interior of a shaft. Fay paste a. The claylike matrix of a dirty sandstone; e.g., the microcrystalline matrix of a graywacke, consisting of quartz, feldspar, clay minerals, chlorite, sericite, and biotite. AGI b. The mineral substance in which other minerals are embedded; groundmass (as of a porphyry). Webster 2nd c. An imitation gemstone made from a certain type of lead glass; loosely applied to all glass imitation gemstones. Anderson d. A white clay body. e. In magnetic particle suspension, finely divided ferromagnetic particles in paste form used in the wet method. f. A slurry of sulfur and water, usually containing 30% to 50% of finely divided elemental sulfur. g. Material of which a porcelain body is formed. Hard paste (pite dure), composed of china stone and china clay, is true porcelain. Soft paste (pite tendre), composed of glass or frit with white, is artificial porcelain. h. Comparatively concentrated dispersion (greater than 10% by volume) of fine-solid or semisolid particles in a liquid; often shows elastic or plastic behavior. Bennett paste fill 2260

a. A class of backfills that has low water content; high densities (> or =75% by lot); and consistency, transport, and deposition properties different from those of traditional lowconcentration slurries or other types of high-concentration backfill. Aref b. Paste fill (high pulp density) that does not settle out of suspension at zero flow density and does not produce free water when placed in a stope. Uncemented paste fill can generally be mobilized reasonably easily by pumping if left standing in a pipe for many hours. paste pumping The transport and placement of high-concentration, low-slump material by positive displacement through pipelines by pumps, similar to those used for concrete pumping. See also: paste fill pasting The operation of mudcapping or plaster shooting whereby rock is blasted without drilling. An explosive is placed on top of the rock and covered by a cap of mud or similar material. patch a. A mine village, usually built and owned by a coal company. Korson b. A small placer property. patchy Distributed in an irregular manner, as when ore occurs in bunches or sporadically. Fay pat coal Scot. The bottom, or lowest, coal sunk through in a shaft. Fay patent A document that conveys title to the ground, and no further assessment work need be done; however, taxes must be paid. The procedure of obtaining a patent is divided into five steps: (1) a mineral surveyor is paid to make a patent survey, to adjust boundaries and correct errors, in which case an amended location should be made; (2) at least $500 worth of improvement must have been made per claim; (3) the presence of valuable mineral must be proven beyond reasonable doubt; (4) the matter is taken up with the local land office, and the proper notices must be published in the papers for a specified time; and (5) the purchase price of the land is paid and the patent is received. Lewis patent ax 2261

A type of surfacing machine employed to remove irregularities from the surface of blocks of stone. patented claim A claim to which a patent has been secured from the U.S. Government, in compliance with the laws relating to such claims. See also: patent patented rope Galvanized steel rope. Pryor, 3 patent survey An accurate survey of a mineral claim by a U.S. deputy surveyor as required by law to secure a patent (title) to the claim. Fay Patera process A metallurgical process consisting of a chloridizing roasting, leaching with water to remove base metals (some silver is dissolved and must be recovered), leaching with sodium hyposulfite for silver, and the precipitation of silver by sodium sulfide. The process was first carried out by von Patera at Joachimstal (Jachymov), Czech Republic. Liddell; Fay paternoster pump A chain pump; named from fancied resemblance of the disks and endless chain to a rosary. Standard, 2 pathfinder In geochemical exploration, a relatively mobile element or gas that occurs in close association with an element or commodity being sought, but can be more easily found because it forms a broader halo or can be detected more readily by analytical methods. A pathfinder serves to lead investigators to a deposit of a desired substance. Often called indicator element, but this latter term is restricted by some authors to elements that are important components of the ores being sought. AGI path of percolation See: line of creep patina 2262

Strictly, the green film formed on copper and bronze after long exposure to the atmosphere. By extension, the term is applied to a film of any sort formed on wood, marble, chert, or other material after weathering or long exposure. See also: desert varnish patinated chert Chert nodules with weathered or case-hardened surface layers. AGI patio a. Mex. Cloth used by miners. b. Sp. Place where minerals are concentrated. The patio floor is one on which silver and/or gold ore is amalgamated. See also: patio process; arrastre. Pryor, 3 patio process The patio process, dating back to the 16th century, was a crude chemical method for the recovery of silver by amalgamation in low heaps with the aid of salt and copper sulfate (magistral). See also: patio Liddell patronite A monoclinic mineral, VS4 (?) ; synthetic VS4 is soft, gray-black, fine-grained; impure material constitutes an important ore mineral in the vanadium deposit at Minasragra, Peru. pattern a. As applied to diamond bits, the design formed by spacing and distributing the diamonds in conformance with a predetermined geometric arrangement on the crown of a bit. See also: concentric pattern; eccentric pattern. Long b. The system followed in spacing boreholes. See also: checkerboarded; pattern shooting. Long pattern molder One who makes sand molds for castings; a molder. Standard, 2 pattern shooting In seismic prospecting, the use of a number of energy sources arranged in a definite geometric pattern. AGI Patterson agitator 2263

An agitator of the Pachuca-tank type in which air is replaced by a solution or water, under pressure from a centrifugal pump. See also: Pachuca tank Pattinson process A process for separating silver from lead in which the molten lead is slowly cooled, so that crystals poorer in silver solifidy out and are removed, leaving the melt richer in silver. ASM, 1 Pattinson's pots A series of pots for separating silver and lead by making use of the fact that the melting point of their alloys rises as the percentage of silver increases. Standard, 2 Paulin altimeter This instrument measures barometric pressure and is quite accurate for a portable instrument. It can be used for finding the difference in pressure between points at various elevations without checking the setting of the pointer, or it can be checked against a mercury barometer and then used as a portable barometer. It is useful in making a survey of the drop in ventilation pressure throughout a mine. paulingite An isometric mineral, (K2 ,Ca,Na2 ,Ba)5 [Al10 Si32 O84 ].34-44H2 O ; zeolite group; forms rhombic dodecahedra; at the Columbia River Rock Island Dam, Wenatchee, WA. Pauling's rules Generalizations about coordination polyhedra and the ways they fit together in stable ionic crystal structures: (1) A coordination polyhedron of anions forms about each cation. (2) Electronic neutrality is maintained over short atomic distances. (3) Coordination polyhedra tend not to share edges or faces. (4) Highly charged cations minimize sharing of polyhedral elements. pavement a. A layer immediately underlying coal or any other workable material. Arkell b. The floor of a mine. c. Any construction superimposed on a subgrade to reduce loading stresses and to protect it against the abrasive effects of traffic and weather. Nelson d. See: base rock e. A bare rock surface that suggests a paved road in smoothness, hardness, horizontally, surface extent, or close packing of its units; e.g., boulder pavement, glacial pavement, desert pavement, limestone pavement, erosion pavement. AGI pavilion 2264

Any of the undersides and corners of a brilliant-cut gem; they lie between the girdle and the collet. Hess paving breaker An air hammer that does not rotate its steel. Nichols, 1 paving sand A type of commercial sand with applications divided into three general classes: concrete pavements, asphaltic pavements, and grouting. pavonite A monoclinic mineral, (Ag,Cu)(Bi,Pb)3 S5 ; at the Porvenir Mine, Bolivia. The synthetic phase, AgBi3 S5 , has the same X-ray pattern. pawl A tooth or set of teeth designed to lock against a ratchet. Nichols, 1 paxite A monoclinic mineral, CuAs2 ; pseudo-orthorhombic; forms intergrowths with novakite, koutekite, and arsenic; in Bohemia, Czech Republic. pay (a) That portion of a formation, deposit, prospect, or mine in which valuable mineral, oil, or gas is found in commercial quantity. (b) Profitable ore. See also: pay dirt. pay dirt a. Gravel. Of alluvial deposits, sand rich enough to be excavated and treated to recover its valuable contents. See also: pay streak Pryor, 3 b. S. Afr. The same as payable ore, but in an alluvial deposit. Also called pay rock. See also: pay ore c. Earth, rock, etc., that yields a profit to a miner. Webster 3rd pay formation A layer or deposit of soil or rock whose value is sufficient to justify excavation. Nichols, 1 pay gravel 2265

a. Gravel containing sufficient heavy mineral to make it profitable to work. Nelson b. In placer mining, a rich strip or lead of auriferous gravel. See also: pay ore pay limit S. Afr. Grade below which the mining of ore is considered to become unpayable. There has been much discussion about mining below the pay limit for technical reasons, as a result of taxation, or to conserve natural resources. Beerman pay load a. In any winding or haulage system, the pay load is the weight of coal, ore, or mineral handled as distinct from dirt, stone, or gangue. Nelson b. The mineral raised up the shaft from an underground mine. Sinclair, 5 pay material The mineral to be recovered. Austin pay ore Rock that, at current cost of discovery, development, and exploitation, can be mined, concentrated and/or smelted profitably at the ruling market value of products. Ore below this value or cut (the threshhold value) is unpay. Syn: pay rock pay gravel. Pryor, 3 pay out To slacken or to let out rope. pay rock See: pay ore pay shoot A portion of a deposit composed of pay ore; generally a dipping band within a more continuous vein. See also: pay streak pay streak a. The area of economic concentration of gold in a placer deposit. Bateman, 2 b. The part of a vein or area of a placer deposit that carries the profitable or pay ore. See also: pay dirt; pay shoot. CF: pay ore peachblossom ore 2266

See: erythrite pea coal In anthracite only, coal small enough to pass through a mesh 3/4 to 1/2 in (1.9 to 1.3 cm) square, but too large to pass through a 3/8-in (9.5-mm) mesh. When buckwheat coal is made, the size marketed as pea is sometimes larger than the above; known also as No. 6 coal. See also: anthracite coal sizes peacock coal Iridescent coal, the iridescence of which is due to a thin film of some substance deposited on the surface of the coal along minute cracks. Arkell peacock ore Informal name for an iridescent copper mineral having a lustrous, tarnished surface exhibiting variegated colors, such as chalcopyrite and esp. bornite. Also called peacock copper. See also: bornite pea gravel Clean gravel, the particles of which are similar in size to that of peas. AGI pea grit The term pea grit has been used for a coarse pisolitic limestone. Such usage should be discontinued; it is erroneous. The term grit should be reserved for a coarse-grained sandstone composed of angular particles. Rice, 1 pea iron ore A variety of pisolitic limonite or "bean ore" occurring in small, rounded grains or masses. Syn: pea ore peak load Maximum permitted power draft from an electric supply main. Pryor, 3 peak loading The maximum number of tons of a specified material to be carried by a conveyor per minute in a specified period of time. NEMA, 2 peak particle velocity 2267

The maximum rate of change of ground displacement with time. peak stope Flat stope advanced (overhand if deposit is inclined) in slanted steps, each flat forming a separate working place. Pryor, 3 pea ore a. Eng. Rounded grains of hydrated peroxide of iron, or silicate of iron, commonly found in cavities of Jurassic limestone. See also: bean ore b. A variety of pisolitic limonite or bean ore occurring in small, rounded grains or masses. Syn: pea iron ore pearceite A monoclinic mineral, Ag16 As2 S11 , having copper as an apparent necessary minor component; forms pseudorhombohedral tabular crystals or may be massive; metallic black; brittle; in low-to moderate-temperature silver and base-metal ores. pearl A dense spherical calcareous concretion, usually white or light-colored, consisting of occasional layers of conchiolin and predominant nacrous layers of aragonite (or rarely calcite); deposited concentrically about a foreign particle within or beneath the mantle of various marine and freshwater mollusks; occurs either free from or attached to the shell. pearl ash Potassium carbonate, K2 CO3 ; esp., an impure product obtained by partial purification of potash from wood ashes. Webster 3rd pearlite The lamellar mixture of ferrite and cementite in the microstructure of slowly cooled ironcarbon base alloys occurring normally as a principal constituent of both steel and cast iron. Webster 3rd pearlite iron a. In general, pearlite iron is gray cast iron consisting of graphite in a matrix of pearlite; i.e., without free ferrite. CTD b. In particular, pearlite iron is a German proprietary name denoting an iron of low silicon content, which is caused to solidify gray by the use of heated molds. CTD pearl mica 2268

See: margarite pearl opal See: cacholong pearl sinter A variety of opal. Syn: fiorite Fay pearl spar Dolomite occurring in rhombohedrons having a pearly luster. Syn: ankerite; bitter spar. See also: dolomite pearlstone See: perlite pearly Applied to minerals having a luster like a pearl; e.g., talc, brucite, and stilbite. See also: nacre peastone See: pisolite peat There are two types of peat, low moor (Flachmoor) and high moor (Hochmoor) peat. Low moor peat is the most common starting material in coal genesis. It therefore constitutes a caustobiolith of low diagenetic degree. Peat is formed in marshes and swamps from the dead, and partly decomposed remains of the marsh vegetation. Stagnant ground water is necessary for peat formation to protect the residual plant material from decay. Peat has a yellowish brown to brownish black color, is generally of the fibrous consistency, and can be either plastic or friable; in its natural state it can be cut; further, it has a very high moisture content (above 75%, generally above 90%). It can be distinguished from brown coal by the fact that the greater part of its moisture content can be squeezed out by pressure (e.g., in the hand). Peat also contains more plant material in a reasonably good state of preservation than brown coal. Individual plant elements, such as roots, stems, leaves, and seeds, can commonly be seen in it with the unaided eye. Failing that, treatment of peat with dilute alkali will make visible many of these plant tissues. Further, peat is richer in cellulose than brown coal (reaction with Fehling's solution). Unlike brown coal, peat still contains cellulose, protected by lignin 2269

or cutin, which gives a reaction with chlorzinc iodide. Correspondingly, peat shows under the microscope tissues that have not undergone either lignification, suberinization, or cutinization; this is not the case in brown coal. The reflectance of peat is low (about 0.3%). Microscopic examination is best undertaken with transmitted light. IHCP peat bed An accumulation of peat. Fay peat blasting A method enabling a road to be built across peat deposits. Hard filling is first dumped over the route to a height equal to the ascertained depth of the peat, into which blasting charges are inserted. By the action of blasting, the peat is displaced outwards and the hard fillings sink into place and can then be consolidated. Hammond peat bog A bog containing peat; an accumulation of peat. Webster 3rd peat gel See: dopplerite peat hag A pit or quag formed by digging out peat. Standard, 2 peat machine A machine for grinding and briquetting peat. Webster 3rd peatman A digger or seller of peat. Webster 3rd peat moss Any moss from which peat has formed or may form. Webster 3rd peat press A machine for making bricks of peat fuel. Standard, 2 peat spade 2270

A spade with an L-shaped blade for cutting out peat in blocks. Webster 3rd peat-to-anthracite theory The theory that there were progressive stages in the conversion of vegetable matter into the various grades of coal of the Carboniferous system. Thus, peat forms at an early stage in coal formation and lignite at an intermediate stage, and by further compression and alteration, bituminous and anthracite coals were formed. See also: Hilt's law Nelson pebble a. A general term for a small, roundish, esp. waterworn stone; specif. a rock fragment larger than a granule and smaller than a cobble, having a diameter in the range of 4 to 64 mm (-2 to -6 phi units, or a size between that of a small pea and that of a tennis ball), being somewhat rounded or otherwise modified by abrasion in the course of transport. In Great Britain, the range of 10 to 50 mm has been used. The term has been used to include fragments of cobble size; it is frequently used in the plural as a syn. of "gravel". Syn: pebblestone b. Transparent and colorless quartz crystal, such as Brazilian pebble. Webster 3rd c. Grinding media for ball or semi-autogeneous mills. As a rule, these are either hard-flint pebbles or hard-burned, white porcelain balls. pebble armor A concentration of pebbles coating a desert area. The pebbles are usually the residual product of wind erosion and are closely fitted together so as to cover the surface in the manner of a mosaic. Also called desert pavement. See also: lag gravel pebble dike a. A clastic dike composed largely of pebbles. AGI b. A tabular body containing sedimentary fragments in an igneous matrix, as from the Tintic district in Utah; e.g., one whose fragments were broken from underlying rocks by gaseous or aqueous fluids of magmatic origin and injected upward into country rock, becoming rounded owing to the milling and/or corrosive action of the hydrothermal fluids. AGI pebble gravel An unconsolidated deposit consisting mainly of pebbles. AGI pebble jack Sphalerite in small crystals or pebblelike grains not attached to rock, but found in clay in wall rock cavities. pebble mill 2271

Horizontally mounted cylindrical mill, charged with flints or selected lumps of ore or rock. Usually long and high discharge. See also: ball mill pebble phosphate A secondary phosphorite of either residual or transported origin, consisting of pellets, pebbles, and nodules of phosphatic material mixed with sand and clay, such as occurs in Florida; e.g., land-pebble phosphate and river-pebble phosphate. See also: phosphorite pebble powder A gunpowder or black powder pressed and cut into large cubical grains so as to make it slow burning. Webster 3rd pebblestone See: pebble pecopteris A fernlike tree of the coal forest, with small ovate pinnules that are attached to the pinnate axis by their whole breadth. Nelson Pecos ore a. A gossan containing lead and silver. Fay b. Tasmania. A yellowish, earthy mixture of oxides of iron, lead, and antimony containing silver; mostly massicot. Fay pectolite A triclinic mineral, NaCa2 Si3 O8 (OH) ; isomorphous with serandite; forms compact masses or fibers; commonly associated with zeolites in cavities and veins in mafic rocks. pedalfer Soil enriched in alumina and iron in regions of high temperature and humid climate that are marked by forest cover. CF: pedocal pedestal A relatively slender neck or column of rock capped by a wider mass of rock and produced by undercutting as a result of wind abrasion (as in the Southwestern United States.) or by differential weathering. See also: pedestal rock pedestal boulder 2272

a. A class of blocks perched on pedestals of limestone. AGI b. Isolated masses or rock above and resting on a smaller base or pedestal. pedestal rock An isolated, residual or erosional mass of rock supported by or balanced on a pedestal. The term is also applied to the entire feature. See also: pedestal boulder pedestrian-controlled dumper A small dumper controlled by a person walking alongside it. Syn: power barrow pediment A broad, gently sloping rock-floored erosion surface or plain of low relief, typically developed by running water in an arid or semiarid region at the base of an abrupt and receding mountain front or plateau escarpment; underlain by bedrock that may be bare, but is more often partly mantled with a thin discontinuous veneer of alluvium derived from the upland masses and in transit across the surface. AGI pedimentation The process of pediment formation. pediment pass A narrow, flat, rock-floored tongue extending upslope from the main pediment and penetrating a mountain sufficiently to meet another pediment slope extending into the mountain from the other side. pedion A crystal form consisting of a single crystal face. pediplane Broad, rock-cut, thinly alluviated surface formed by the coalescence of adjacent pediments and desert domes. pedis possessio The actual possession of a piece of mineral land to the extent needed to give the locator room to work and to prevent probable breaches of the peace, but not necessarily to the extent of a mining claim. 2273

pedocal Soil enriched in calcium carbonate, accumulating in regions of low temperature, low rainfall, and prairie vegetation. CF: pedalfer pedogenesis The formation of soil from parent material. pedogeochemical prospecting Synonymous with geochemical soil survey. Hawkes, 1 pedologic horizon See: soil horizon pedology The science that treats soils, their origin, character, and utilization. AGI pedometer A pocket-size instrument that registers the number of steps taken by the person carrying it. AGI pedosphere The part of the Earth in which soil-forming processes occur. peeler a. One of a set of blades that picks up and channels water moved outward by the impeller of a centrifugal pump. Nichols, 1 b. An iron implement with a flattened end and ring handle, which is used by a baller in placing blooms, ingots, etc., in a reheating furnace. Standard, 2 c. See: calk Peerless explosive High explosive; used in mines. Bennett peg a. A surveyor's mark. b. To mark out a miner's claim at the four corners by pegs bearing the claimant's name. Sometimes used as "peg out." Webster 3rd; Fay 2274

peg adjustment The adjustment of a spirit-leveling instrument of the dumpy-level type in which the line of collimation is made parallel with the axis of the spirit level by means of two stable marks (pegs) the length of one instrument sight apart. AGI pegleg An abrupt change or sharp bend in the course of a borehole. Also called dogleg. Long pegmatite An exceptionally coarse-grained igneous rock, with interlocking crystals, usually found as irregular dikes, lenses, or veins, esp. at the margins of batholiths. Most grains are 1 cm or more in diameter. Although pegmatites having gross compositions similar to other rock types are known, their composition is generally that of granite; the composition may be simple or complex and may include rare minerals rich in such elements as lithium, boron, fluorine, niobium, tantalum, uranium, and rare earths. Pegmatites represent the last and most hydrous portion of a magma to crystallize and hence contain high concentrations of minerals present only in trace amounts in granitic rocks. Adj: pegmatitic. Syn: giant granite CF: symplectite pegmatitic a. Said of the texture of an exceptionally coarsely crystalline igneous rock. AGI b. Occurring in, pertaining to, or composed of pegmatite. Syn: pegmatoid pegmatitic stage a. A final stage in the normal sequence of crystallization of a magma at which the residual fluid is sufficiently enriched in volatile materials to permit the formation of coarse-grained rocks (pegmatite) more or less equivalent in composition to the parent rock. CF: orthomagmatic stage AGI b. The late stages of magma crystallization in Stype, 2-mica granites. pegmatitization The process of formation of, introduction of, or replacement by pegmatite. pegmatoid See: pegmatitic pegmatolite 2275

See: orthoclase peg point A pointed bar in a slide clamp. Used to brace a machine during work. Nichols, 2 peg structure A structure characterized by tiny peg-shaped cavities, some with intricate profiles, penetrating the interior of crystals; typical of melilite. AGI Pehrson-Prentice process A method of producing steel direct from ore. Osborne Peirce-Smith converter A cylindrical-type converter having a basic (magnesite) lining; used for treating copper. Newton, 1 Peirce-Smith process A basic converting process for copper matte in a magnesite-lined converter. The iron of the matte is fluxed by silica added before the process begins. Liddell Peissenberg ram See: ram scraper. PEL See: permissible exposure limit pelagic deposit or sediment Deposit found in deep water far from shore and may be predominantly either organic or inorganic in origin. Such deposits are light colored, reddish or brown, fine grained, and generally contain some skeletal remains of plankton organisms. Those that contain less than about 30% of organic remains are called red clay; those that contain more than about 30% of organic remains are known as oozes. Hunt pelagochthonous A term applied to coal deposits formed from submerged forests and driftwood. Tomkeieff 2276

Pelatan-Clerici process A continuous process of dissolving silver or gold in cyanide solution and simultaneously precipitating the precious metals with mercury in the same vessel, with an electrical current assisting precipitation. Liddell peldon An English term for a very hard, smooth compact sandstone with conchoidal fracture that occurs in coal measures. Pele's hair A natural spun glass formed by blowing-out during quiet fountaining of fluid lava, cascading lava falls, or turbulent flows, sometimes in association with Pele's tear pyroclast. A single strand, with a diameter of less than 1/2 mm, may be as long as 2 m. Etymol: Pele, Hawaiian goddess of fire. AGI Pele's tears Small, solidified drops of volcanic glass behind which trail pendants of Pele's hair. They may be tear shaped, spherical, or nearly cylindrical. Etymol: Pele, Hawaiian goddess of fire. AGI pelite a. A sediment or sedimentary rock composed of the finest detritus (clay- or mud-size particles); e.g., a mudstone, or a calcareous sediment composed of clay and minute particles of quartz. The term is equivalent to the Latin-derived term lutite. AGI b. A fine-grained sedimentary rock composed of more or less hydrated aluminum silicates with which are mingled small particles of various other minerals; an aluminous sediment. Etymol: Greek pelos, clay mud. See also: psammite; psephite. Also spelled pelyte. AGI pelitic a. Pertaining to or characteristic of pelite; esp. said of a sedimentary rock composed of clay, such as a pelitic tuff representing a consolidated volcanic ash consisting of claysize particles. AGI b. Said of a metamorphic rock derived from a pelite; e.g., a pelitic hornfels or a pelitic schist, derived by metamorphism of an argillaceous or a fine-grained aluminous sediment. AGI pelitic gneiss A gneiss derived from the metamorphism of argillaceous sediments. 2277

pelitic hornfels A fine-grained, nonfissile metamorphic rock derived from an argillaceous sediment. See also: hornfels pelitic schist A schistose metamorphic rock derived from an argillaceous sediment. See also: schist pelletizing A method in which finely divided material is rolled in a drum or on an inclined disk, so that the particles cling together and roll up into small, spherical pellets. The addition of a binder may be required to produce a pellet of acceptable mechanical strength. Newton, 1 Pelletol A waterproof, free-running blasting agent. Pelletol is a high explosive, but is not considered cap sensitive and normally cannot be initiated with a cap, except under perfect confinement in small-diameter boreholes. Du Pont, 1 pellet powder Black powder pressed into cylindrical pellets 2 in (5.1 cm) in length and varying from 11/4 to 2 in (3.2 to 5.1 cm) in diameter. Each pellet has a 3/8-in (9.5-mm) hole through its center to permit fuse insertion. Carson, 1 pellet texture A concretionary texture characterized by minute pellets of colloidal or replacement origin and closely resembling oolites. Schieferdecker pell-mell structure Coarse deposits of waterworn materials in which there is an absence of bedding. AGI pelter A worker employed in a coal mine to take down pelt (shaly stone) from the roof of a narrow seam, to make enough height for a coal cutting machine. CTD Pelton wheel

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An impulse water turbine with buckets bolted to its periphery, which are struck by a high velocity jet of water. This turbine is most efficient under a head of from 900 to 1,000 ft (274 to 305 m) or more. See also: impulse turbine pelyte See: pelite pena A large stone or boulder. Etymol: Spanish, "rock." penalty a. In connection with a contract for purchase of mineral concentrates by a custom smelter, a deduction from an agreed price for failure to reach an agreed assay value or to eliminate specified contaminants; charged at so much per unit of mineral or metal concerned. Pryor, 3 b. In a construction contract, a penalty clause is one that imposes a penalty for failure to complete work to agreed time, specification, etc. Pryor, 3 Penang tin Pig tin of about 99.95% purity, obtained from the Penang Mines in Malaysia. Bennett Penberthy anoloader A simple powder loader with a high air velocity that is used in Canada in underground work for charging holes with a depth of up to 14 ft (4 m). pencil-core bit The very-thick-wall, medium-round nose bit that cuts a pencil-size core. The bit is essentially a noncoring bit, and in most instances no attempt is made to recover the verysmall-diameter core as a sample. Syn: pencil-coring crown pencil-coring crown See: pencil-core bit pencil ganister A variety of ganister characterized by fine carbonaceous streaks or markings; so called from the likeness of these to pencil lines. The carbonaceous traces are often recognizable as roots and rootlets of plants. AGI 2279

penciling Reduction in the fire face area of the brick, in which slag erosion at the joints is pronounced. pencil mark Aust. A thin bed of dark slate, about the thickness of the lead of a carpenter's pencil, that is parallel to the indicator. See also: indicator pencil ore Hard, fibrous masses of hematite that can be split up into thin rods. CMD pencil stone A compact pyrophyllite used for making slate pencils. Webster 3rd pencil structure A very pronounced lineation, such as that produced by intersecting bedding and cleavage planes in slate. pendant See: roof pendant pendletonite See: karpatite pendulum In mechanized mining, the arm that extends between the fulcrum jack and the swivel or angle trough or turn. Jones, 1 pendulum buffer In Vermont, large wooden blocks covered with felt pads that are propelled back and forth by means of a crank and pitman. Used for polishing monumental stone. pendulum mill See: Griffin mill; Huntington mill. 2280

penecontemporaneous structure Small folds and faults that form in sediments shortly after they are deposited, in igneous rocks as they solidify, and in metamorphic rocks as they recrystallize. peneplain A nearly horizontal surface of slight relief and very gentle slopes, formed by the subaerial degradation of the land almost to baselevel; the penultimate stage of the old age of the land produced by such degradation. By extension, such a surface uplifted to form a plateau and subjected to renewed degradation and dissection. See also: baseleveled plain. peneplanation The subaerial degradation of a region approx. to base level, forming a peneplain. penetrating pulley A pulley around which a wire cable runs in cutting marble. Its thickness is less than the diameter of the wire and consequently, it can follow the wire as the latter cuts into the stone. penetration feed See: feed rate penetration log The penetration speed of a drill related to the size of the hole and bit, mud pressure, speed of rotation, weight on bit, etc. From the results, which are plotted as penetration curves, the thickness of coal and dirt bands in the borehole can be determined with reasonable accuracy. Nelson penetration macadam Screened gravel or crushed stone aggregate, bound by bituminous grouting, the binder being introduced after compaction of the aggregate. Nelson penetration per blow The distance a drive-type soil sampler, casing, drivepipe, pile, or penetrometer is driven into the formation being tested by each blow delivered by a specific-size drivehammer allowed to fall a specific distance. Long penetration rate 2281

The actual rate of penetration of drilling tools. See also: feed rate; drilling rate. BS, 9 penetration resistance a. The number of blows of a hammer of specified weight falling a given distance required to produce a given penetration into soil of a pile, casing, or sampling tube. Also called standard penetration resistance; proctor penetration resistance. ASCE b. The unit load required to maintain constant rate of penetration into soil by a probe or instrument. ASCE c. The unit load required to produce a specified penetration into soil at a specified rate by a probe or instrument. For a proctor needle, the specified penetration is 2-1/2 in (6.35 cm) and the rate is 1/2 in/s (1.27 cm/s). ASCE penetration resistance curve The curve showing the relationship between the penetration resistance and the water content. Also called proctor penetration curve. ASCE penetration speed The speed at which a drill can cut through rock or other material. See also: overall drilling time penetration test A test to determine the relative densities of noncohesive soils, sands, or silts; e.g., the standard penetration test that determines the number of blows required by a standard weight, when dropped from a standard height (30 in or 76.2 cm per blow), to drive a standard sampling spoon a standard penetration (12 in or 30.5 cm); or the dynamic penetration test, which determines the relative densities of successive layers by recording the penetration per blow or a specified number of blows. See also: cone penetration test penetration twin A twin crystal in which two parts interpenetrate with each other and share a common volume. Syn: interpenetration twin penetrometer An instrument to assess the strength of a coal seam, its relative workability, and the influence of roof pressure. See also: sounding; coal penetrometer. Nelson pennant flag

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Unproductive grit and sandstone between the Lower and Upper Coal Measures, South Wales and Bristol, England, coalfield. Largely quarried for paving and building. Also called pennan grit; pennant stone. Arkell pennantite A monoclinic mineral, Mn5 Al(Si3 Al)O10 (OH)8; chlorite group; excellent cleavage with flexible laminae; commonly associated with manganese deposits. pennine A pseudotrigonal variety of clinochlore. See also: penninite Pennine system Eng. The original and typical series of Carboniferous rocks, comprising the Upper Old Red Sandstone, the Mountain limestone, the Millstone grit, and the Coal Measures. Standard, 2 penning See: cribbing penning gate Regulating device used to govern the draft of water from a dam; may incorporate arrangements for holding back sediment or floating detritus. Pryor, 3 penninite A green crystallized chlorite from the Penninic Alps. Composition essentially the same as that of clinochlore, (Mg,Fe2+ )5 Al(Si3 Al)O10 (OH)8 . See also: pennine. Fay Pennsylvanian A period of the Paleozoic Era (after the Mississippian and before the Permian), thought to have covered the span of time between 320 million years and 280 million years ago; also, the corresponding system of rocks. It is named after the state of Pennsylvania in which rocks of this age are widespread and yield much coal. It is the approximate equivalent of the Upper Carboniferous of European usage. AGI pennyweight One-twentieth troy ounce (1.56 g). Used in the United States and in England for the valuation of gold, silver, and jewels. Abbrev.: dwt; pwt. Standard, 2 2283

penroseite An isometric mineral, (Ni,Co,Cu)Se2 ; pyrite group; cubic cleavage; forms radiating columnar masses; occurs in Bolivian mines near Colquechaca. Formerly called blockite. penstock a. A sluice or gate for restraining, deviating, or otherwise regulating the flow of water, sewage, etc.; a floodgate. Webster 3rd b. The barrel of a wooden pump. c. A closed conduit for supplying water under pressure to a water wheel or turbine. Seelye, 1 pentagon A polygon having five sides. Jones, 2 pentahydrite A triclinic mineral, MgSO4 .5H2 O ; chalcanthite group; highly soluble. Formerly called allenite. pentahydroborite A triclinic mineral, CaB2 O(OH)6 .2H2 O ; colorless; forms small anhedra at a skarn in the Ural Mountains, Russia. pentasol xanthate Collector agent use in flotation, in which the hydrocarbon group is crude and unfractionated amyl alcohol. Symbol, Z-6. Pryor, 3 pentavalent a. Having a valence of five. Webster 3rd b. Having five valences. Webster 3rd; Handbook of Chemistry and Physics, 2 Pentelic marble One of the most famous of ancient statuary marbles; from Mount Pentelicus, Greece. penthrit See: penthrite penthrite 2284

Pentaerythritol tetranite. Used as an explosive. Syn: penthrit; niperyth. Bennett pentice a. A rock pillar left, or a heavy timber bulkhead placed, in the bottom of a two-or-morecompartment-deep shaft through which to sink it further. A small, auxilliary steam or air hoist, dumping apparatus, and pocket or bin are installed above the pentice; through an opening in it, sinking by short lifts is carried on while the shaft is in use above the pentice. Practiced in the Michigan copper country. Hess b. A cover, protection, or roof over a sinking shaft. The cover contains a trapdoor through which the rope and bowk pass. See also: Galloway stage Nelson c. In shaft sinking, a solid rock pillar left in the bottom of the shaft for overhead protection of miners while the shaft is being extended by sinking. pentlandite a. An isometric mineral, (Fe,Ni)9 S8 ; octahedral parting; metallic; pale bronze-yellow; nonmagnetic; generally associated with pyrrhotite, less commonly associated with chalcopyrite in magmatic sulfide deposits; the principal sulfide ore of nickel. b. The mineral group argentopentlandite, cobalt pentlandite, geffroyite, manganese-shadlunite, pentlandite, and shadlunite. pentolite A mixture of PETN and TNT used primarily for boosters and cast primers; military grade pentolite is usually 50% of each ingredient by weight; commercial pentolite often has a lower PETN content. pentrough The trough in which the penstock of a water wheel is placed. Fay peon a. The movable vertical post of an arrastre. b. A prop, post, or stall. c. Mex. Helper; a common laborer. pepper-and-salt texture Said of disseminated ores, esp. with dark grains in a light matrix. AGI peptization

2285

a. Liquefaction of a gel; deflocculation and dispersion of solids in a pulp; conversion of a substance to its colloidal state by subdivision. Pryor, 3 b. A dispersion due to the addition of electrolytes or other chemical substances. Brantly, 1 peptize To bring into colloidal solution; to convert into a solution. Syn: deflocculate peralkaline Said of igneous rocks in which the molecular proportion of alumina is less than that of soda and potash combined. peraluminous Said of igneous rocks in which the molecular proportion of alumina exceeds that of soda, potash, and lime combined. percentage extraction The proportion of a coal seam that is removed from a mine. The remainder may represent coal in pillars or coal that is too thin or inferior to mine or is lost in mining. Shallow coal mines working under townships, reservoirs, etc., may extract only about 50% of the entire seam, the remainder being left as pillars to protect the surface. Under favorable conditions, longwall conveyor mining may extract from 80% to 95% of the entire seam. With pillar methods of working, the extraction ranges from 50% to 90%, depending on local conditions. Nelson percentage ore N.S.W. In most cases, understood to be the percentage of the metallic element present in the ore. New South Wales percentage subsidence The measured amount of subsidence expressed as a percentage of the thickness of coal extracted. See also: full subsidence percentage support The percentage of the total wall area of a mine that will actually be covered by supports. Spalding perch 2286

a. Any of various units of measure for stonework, (including 24-3/4 ft3 (0.70 m3 ) representing a pile 1 rod (5.0 m) long by 1 ft (0.3 m) by 1-1/2 ft (0.46 m); or 16-1/2 ft3 (0.47 m3 ); or 25 ft3 (0.71 m3 ). Webster 3rd b. A measure of length equal to 5-1/2 yd or 16-1/2 ft (5.0 m); a rod, or pole; also, a square rod (25.3 m2 ). Webster 2nd perched ground water Unconfined ground water separated from an underlying main body of ground water by an unsaturated zone. AGI perched water See: perched ground water perched water table The water table of a body of perched ground water. See: vertical sand drain percolation a. In the leaching treatment of minerals, a process whereby a solvent flows gently upward or downward through a bed of ore-bearing material sufficiently coarse textured to permit this flow. See also: sand leaching b. Slow laminar movement of water through small openings within a porous material. Also used as a syn. of infiltration. Flow in large openings such as caves is not included. CF: infiltration percolation leaching The selective removal of the metal values from a mineral by causing a suitable solvent or leaching agent to seep into and through a mass or pile of material containing the desired mineral. percolation rate The rate, expressed as either velocity or volume, at which water percolates through a porous medium. AGI percussion bit A rock-drilling tool with chisellike cutting edges, which when driven by impacts against a rock surface, drills a hole by a chipping action. Long percussion cap See: detonator; primer. 2287

percussion drill a. Drill in which the drilling bit falls with force onto rock. Also, a pneumatic drill in which a piston delivers hammer blows rapidly on the drill shank. Syn: churn drill; cabletool drill; percussion machine. Pryor, 3 b. Sometimes limited to large blasthole drills of the percussion type. Nichols, 1 percussion drilling Act of using a percussion drill. See also: percussion drill percussion figure A pattern of radiating lines produced on a section of a crystal by a blow from a sharp point. percussion machine See: percussion drill percussion powder Powder so composed as to ignite by a slight percussion; fulminating powder. Fay percussion sieve An apparatus in which material is sorted according to size. It consists essentially of superimposed, oppositely inclined sieves, both mechanically agitated by vertical lever and having water sluices. percussion system Applicable to drill machines and/or the methods used to drill boreholes by the chipping action of impacts delivered to a chisel-edged bit. See also: churn drill; percussion drill. Long percussion table Early form of shaking table. See also: concussion table; shaking table. Pryor, 3 percussive boring A system of boring using solid or hollow rods or ropes; may be used for exploratory drilling and for blasting purposes. See also: boring Nelson 2288

percussive drill A pneumatic drill that is used widely in mining for exploration and for blasting purposes. See also: rock drill percussive drilling a. A method of drilling whereby repeated blows are applied by the bit, which is repositioned by intermittent rotation. BS, 12 b. A form of drilling in which the rock is penetrated by the repeated impact of a reciprocating drill tool. Fraenkel percussive machine Any of several types of machine, including heading machines, air picks, and the numerous types of percussive drills. Mason perfect-discharge elevator In the so-called perfect-discharge elevator, there is an extra set of traction or sprocket wheels on the discharge side, so set that they bend the chains back under the head wheels. As a consequence, the discharging chute may be placed directly under the buckets. This elevator will also handle material that packs, and both types of gravitydischarge elevators may be run much slower than the centrifugal type. Pit and Quarry perfect frame A structural frame that is stable under loads imposed upon it from any direction, but which would become unstable if one of its members were removed or one of its fixed ends became hinged. Hammond performance curve Any curve used to show the relationship between properties of coal and results of a specific treatment. BS, 5 perhydrous maceral Maceral having a high hydrogen content, such as exinite and resinite. Tomkeieff periA prefix meaning around or beyond. AGI periblain 2289

A kind of provitrain in which the cellular structure is derived from cortical material. CF: suberain; xylain. AGI periblinite a. The micropetrological constituent, or marceral, of periblain. It consists of cortical tissue almost jellified in bulk, but still showing indications of cell structure under a microscope. AGI b. A distinction of telinite based on botanical origin (cortical tissue). CF: suberinite periclase a. An isometric mineral, MgO; cubic cleavage; colorless to yellow or brown; may be strongly colored by inclusions; occurs in high-temperature metamorphic rocks derived from dolomite. Syn: periclasite b. The mineral group bunsenite, manganosite, monteponite, periclase, and wuestite. periclasite See: periclase periclinal Said of strata and structures that dip radially outward from, or inward toward, a center, to form a dome or a basin. CF: quaquaversal; centroclinal. AGI pericline a. A general term for a fold in which the dip of the beds has a central orientation; beds dipping away from a center form a dome, and beds dipping toward a center form a basin. The term is generally British in usage. See also: centrocline; dome; quaquaversal. AGI b. A variety of albite elongated in the direction of the b-axis and often twinned with this as the twinning axis. It occurs in veins as large milky-white opaque crystals. Pericline is probably an albitized oligoclase. AGI pericline twin A twin crystal, in the monoclinic system, whose twinning axis is the orthoaxis of the crystal. Fay peridot a. A transparent to translucent green gem variety of forsterite in the olivine group. Also spelled peridote. Syn: bastard emerald b. A yellowish-green or greenish-yellow variety of 2290

tourmaline, approaching olivine in color. It is used as a semiprecious stone. See also: olivine peridote See: peridot peridotite A general term for a coarse-grained plutonic rock composed chiefly of olivine with or without other mafic minerals such as pyroxenes, amphiboles, or micas, and containing little or no feldspar. Accessory minerals of the spinel group are commonly present. Peridotite is commonly altered to serpentinite. AGI peridot of Ceylon See: Ceylonese peridot; peridot. perimeter blasting A method of blasting in tunnels, drifts, and raises, designed to minimize overbreak and leave clean-cut solid walls. Holes in the outside row are loaded with very light, continuous explosive charges and are fired simultaneously, so that they shear from one hole to the other. Nelson perimeter of airway In mine ventilation, the linear distance in feet of the airway perimeter rubbing surface at right angles to the direction of the airstream. perimorph A crystal of one species enclosing one of another species. Webster 3rd period a. The geochronologic unit lower in rank than era and higher than epoch, during which the rocks of the corresponding system were formed. It is the fundamental unit of the worldwide geologic time scale. AGI b. A term used informally to designate a length of geologic time; e.g., glacial period. AGI c. The interval of time required for the completion of a cyclic motion or recurring event, such as the time between two consecutive like phases of the tide or a current. AGI d. The duration of one complete cycle of a periodic function; the reciprocal of the frequency of such a function. The independent variable is limited to time. ASM, 1 e. The elements between an alkali metal and the rare gas of next highest atomic number, inclusive, occupying one (a short period) 2291

horizontal row or two (a long period) horizontal rows in the periodic table. CTD f. The time required for the power level of a reactor to change by the factor 2.718, which is known as e. Lyman periodic law The physical and chemical properties of the elements depend on the structure of their atoms and are for the most part periodic functions of the atomic number. See also: periodic table periodic reverse Pertains to periodic change in the direction of flow of the current in electrolysis. It applies to the process and also to the machine that controls the time for both directions. Symbol, PR. ASM, 1 periodic table An arrangement of elements based on the periodic law and proposed in various forms that are usually either short with only short periods (as in Mendeleev's original table) or long with long as well as short periods (as in most modern tables). See also: periodic law peripheral fault A fault along the perimeter of a geologically elevated or depressed region. AGI peripheral speed The distance a given point on the perimeter of a rotating circular object travels, expressed in feet or meters per second; sometimes incorrectly called lineal travel by some drillers. Syn: surface speed peripheral-turbine pump This pump--sometimes called a regenerative pump--is classified with centrifugal pumps, but is designed to develop several times the head obtained from a centrifugal pump having the same-diameter impeller and the same speed. The maximum head developed does not have the same relation to the impeller diameter and speed of the centrifugal pump; it involves size and spacing of the impeller vanes, fluid channels, and other factors. Pit and Quarry peripheral ventilation

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A mine ventilation system in which the upcast shaft for taking air out of a mine is situated at the limits of the mining field or away from the downcast shaft. Also called transverse or one-way ventilation. Syn: transverse ventilation peritectic Said of an isothermal reversible reaction in a crystallizing melt or magma in which a liquid phase reacts with a solid phase to produce another solid phase on cooling. ASM, 1 perlite a. A siliceous volcanic glass having numerous concentric spherical cracks that give rise to an onion-skin structure. Most perlite has a higher water content than obsidian. When perlite is heated to the softening point, it expands, or pops to form a light fluffy material similar to pumice. It is used as lightweight aggregate in concrete, as insulation for liquid fuels, and in potting soils. b. A pearly volcanic glass. perlitic a. Said of the texture of a glassy igneous rock that has cracked owing to contraction during cooling, the cracks forming small spheruloids. It is generally confined to natural glass, but occasionally found in quartz and other noncleavable minerals and as a relict structure in devitrified rocks. AGI b. Pertaining to or characteristic of perlite. AGI permafrost A permanently frozen layer of soil or subsoil, or even bedrock, which occurs to variable depths below the Earth's surface in arctic or subarctic regions. It underlies about onefifth of the world's land area. permafrost drilling a. Boreholes drilled in subsoil and rocks in which the contained water is permanently frozen. Long b. Holes drilled into perenially frozen ground that may be superficial unconsolidated material, bedrock, and ice. When no ice is present, it is called dry permafrost. permalloy An iron-nickel alloy with high magnetic permeability. Nelson permanent adjustment The adjustment of a surveying instrument that is made infrequently and not at each setup. See also: temporary adjustment 2293

permanent expansion Increase in bulk volume as a result of decrease in specific gravity. permanent hardness Hardness of water that cannot be removed by boiling. Opposite of temporary hardness. permanent hard water Hard water that cannot be softened by boiling; water containing magnesium sulfate or calcium sulfate. Bennett permanent magnetism Magnetic property of a substance maintained without external excitation. Pryor, 3 permanent monument A monument of a lasting character for marking a mining claim. It may be a mountain, hill, ridge, hogback, butte, canyon, gulch, river, stream, waterfall, cascade, lake, inlet, bay, arm of the sea, stake, post, monument of stone or boulders, shafts, drifts, tunnels, open cuts, or well-known adjoining patented claims. Fay permanent pump A permanent main pump is one on which a mine depends for the final disposal of its drainage. As it is usually not moved during the life of the mine, its location, installation, and design require careful consideration. A permanent main pump may discharge on the surface, into an underground sump, or into some other part of a mine. permanent set The amount of permanent deformation of a material that has been stressed beyond its elastic limit. AGI permanent shaft support After a shaft has been sunk to a certain depth, the final or permanent lining is inserted. This may consist of: brick walling; concrete blocks shaped to the curvature of the shaft; concrete lining put in liquid form behind shuttering; brick coffering; and cast-iron tubbing. The permanent lining is generally built up in sections, during which operation the temporary lining (such as skeleton tubbing) is removed. Concrete is now widely used as a permanent shaft support. See also: brick walling; lining; steel rectangular shaft supports. Nelson 2294

permanent way The completed assembly of rails, sleepers, fixings, and ballast forming the finished track for a railway. Hammond permanganate A salt of permanganic acid of the type, MnO4 ; dark purple; good oxidizing agent; often used as a disinfectant. Enam. Dict. permeability a. The permeability (or perviousness) of rock is its capacity for transmitting a fluid. Degree of permeability depends upon the size and shape of the pores, the size and shape of their interconnections, and the extent of the latter. It is measured by the rate at which a fluid of standard viscosity can move a given distance through a given interval of time. The unit of permeability is the darcy. See also: millidarcy; coefficient of permeability. AGI b. In geophysics, the ratio of the magnetic induction to the magnetic intensity in the same region. In paramagnetic matter, the permeability is nearly independent of the magnetic intensity; in a vacuum, it is strictly so. But in ferromagnetic matter, the relationship is definite only under fully specified conditions. AGI c. See: coefficient of permeability d. In magnetism, a general term used to express various relationships between magnetic induction and magnetizing forces. These relationships are either absolute permeability, which is the quotient of a change in magnetic induction divided by the corresponding change in magnetizing force, or specific (relative) permeability, the ratio of the absolute permeability to the permeability of free space. ASM, 1 e. In founding, the characteristics of molding materials which permit gases to pass through them. Permeability number is deteremined by a standard test. ASM, 1 f. In powder metallurgy, a property measured as the rate of passage under specified conditions of a liquid or gas through a compact. ASM, 1 permeable Pertaining to a rock or soil having a texture that permits passage of liquids or gases under the pressure ordinarily found in earth materials. Syn: pervious permeameter An instrument for measuring permeability. AGI permineralization A process of fossilization wherein the original hard parts of an animal have additional mineral material deposited in their pore spaces. AGI 2295

permissible a. Means completely assembled and conforming in every respect with the design formally approved by the U.S. Mine Safety and Health Administration for use in gassy and dusty mines. b. A machine or explosive is said to be permissible when it has been approved by the U.S. Mine Safety and Health Administration for use underground under prescribed conditions. All flameproof machinery is not permissible, but all permissible machinery is flameproof. c. A low-flame explosive used in gassy and dusty coal mines. Nichols, 1 permissible blasting device Any device, other than explosives, for breaking down coal that is approved by the U.S. Mine Safety and Health Administration. permissible blasting unit An electrical device for firing blasts, approved by the U.S. Mine Safety and Health Administration. permissible dustiness See: dust-free conditions permissible explosive Explosive that has been tested for safety in handling and approved for use in mines by the U.S. Mine Safety and Health Administration. permissible exposure limit An exposure limit published and enforced by the U.S. Occupational Safety and Health Administration (OSHA) as a legal standard. NSC, 2 permissible hydraulic fluid Any of several commercially available, fire-resistant fluids that are water-in-oil emulsions and can be substituted for flammable hydraulic fluids by users of large machinery, whether the equipment is operated underground or on the surface. permissible lamp Any electric or flame safety lamp that is similar in all respects to a lamp tested and approved by the U.S. Mine Safety and Health Administration. Hess 2296

permissible machine Any drill, mining machine, loading machine, conveyor, or locomotive that is similar in all respects to machines tested and approved by the U.S. Mine Safety and Health Administration for use in gassy mines. permissible mine equipment Equipment that is formally approved by the U.S. Mine Safety and Health Administration after having passed the inspections, the explosion tests, and other requirements specified by the Administration. (All equipment so approved must carry the official approval plate required as identification for permissible equipment.) permissible mine locomotive See: electric permissible mine locomotive permissible motor A motor the same in all respects as a sample motor that has passed certain tests made by the U.S. Mine Safety and Health Administration and installed and used in accordance with the conditions prescribed by the Administration. See also: explosion-proof motor permissible velocity The highest velocity at which water may be carried safely in a canal or other conduit; the highest velocity throughout a substantial length of a conduit that will not scour. Seelye, 1 permit man A member of a geophysical field party whose duty is to obtain permission from landowners for the party to work on their lands, or from public officials for the party to work along highways. AGI permitted See: permitted explosive; permitted light. permitted explosive a. Explosive that has passed the Buxton tests and has been placed on the British list of authorized explosives, implying that they are reasonably safe to manufacture, handle, transport, and use in safety-lamp mines. Upon detonation, a permitted explosive: (1) gives off the minimum possible quantity of noxious gases, and (2) produces a flame of the lowest possible temperature and shortest possible duration, to lessen the risk of 2297

combustible gases ignition. The explosive contains cooling agents, such as sodium chloride and sodium bicarbonate. The first British list of permitted explosives was published in 1899. Nelson b. A permitted explosive is one that has been approved for use in coal mines where there is any possible risk of igniting combustible gases or coal dust. In Great Britain, an explosive is approved by the Minister of Power and placed on the Permitted List after it has passed the official gallery tests prescribed for the particular class of explosives to which it belongs. These tests are carried out at the Safety in Mines Research Establishment's Testing Station at Buxton. McAdam, 2 c. Permitted explosives are divided into four groups: P.1., normal permitted explosives; P.2., sheathed explosives; P.3., eq.s. explosive; P.4., permitted explosives that have passed additional and more stringent tests. BS, 12 d. The term "permissible explosive" is used in the United States. See also: permissible explosive permitted light Locked safety lamp or any other means of lighting, the use of which below ground in British coal mines is authorized by Regulations under the Act. See also: safety-lamp mine permitting process A process in which an applicant files forms to a regulatory agency with required narratives, maps, mine plans, etc., to ensure in advance of mining that the proposed operation will be in compliance with the applicable environmental standards. SME, 1 Permocarboniferous Strata not differentiated between the Permian and Carboniferous systems, particularly in regions where there is no conspicuous stratigraphic break and fossils are transitional. AGI Permotriassic Strata not differentiated between the Permian and Triassic systems, particularly in regions where the boundary occurs within a nonmarine, red beds succession. AGI permutite process See: base exchange perofskite See: perovskite Perosa process 2298

A process by which beryllium is extracted from beryl. perovskite a. An orthorhombic mineral, CaTiO3 ; may have Ca replaced by rare earths and Ti replaced by niobium and tantalum; pseudocubic; massive or in cubic crystals; yellow, brown, or grayish black; occurs in silica-deficient metamorphic and igneous environments such as skarns; also occurs in mafic and alkaline igneous rocks. Also spelled perofskite. b. The mineral group latrappite, loparite, leushite, and perovskite. perpend a. A header extending through a wall so that one end appears on each side of it; a perpendstone border, bondstone, throughstone; through binder. Also called parping; perpender; perpent. Fay b. A vertical joint, such as in a brick wall. Standard, 2 perpendicular separation The separation of a fault as measured at right angles to the fault plane. AGI perpendicular slip The component of the slip of a fault that is measured perpendicular to the trace of the fault on any intersecting surface. AGI perpendicular throw The distance between the two parts of a disrupted bed, dike, vein, or of any recognizable surface, measured perpendicular to the bedding plane or surface in question. It is measured in a vertical plane at right angles to the strike of the disrupted surface. See also: throw persilicic A term proposed by Clarke (1908) to replace acidic. Syn: silicic CF: subsilicic; mediosilicic. AGI persistent Continuous; orebodies are often persistent in depth and metal contents. von Bernewitz personnel proximity survey A survey of radiation conditions at positions occupied by personnel working near apparatus emitting radioactivity. NCB 2299

persorption Deep sorption of gas by liquid. Pryor, 3 persuader A common term for crowbar, lever, or some such article used as a manual aid in moving heavy objects. Crispin perthite A variety of alkali feldspar consisting of parallel or subparallel intergrowths in which the potassium-rich phase (commonly microcline) appears to be the host from which the sodium-rich phase (commonly albite) exsolved; such exsolved areas may be visible to the naked eye, typically forming strings, lamellae, blebs, films, or irregular veinlets; where texture is invisible to the eye but can be resolved with a microscope, it is microperthite. CF: antiperthite; cryptoperthite; microperthite. perthorite A deep-seated igneous rock consisting of alkali feldspar with less than 3% dark minerals. Feldspar, both orthoclase and albite, may be perthitically intergrown as cryptoperthite or as anorthoclase. Hess pervious See: permeable petalite A monoclinic mineral, LiAlSi4 O10 ; perfect cleavage; vitreous; resembles spodumene; a source of lithium salts; in granite pegmatites. petaloid Resembling a flower petal in form, appearance, or texture. Applied to the structure seen in minerals that split into pieces with a smooth polished concave-convex surface that fit into one another somewhat like the petals of an unopened flower bud. Webster 3rd; Fay petcock A small drain valve. Nichols, 1 peter 2300

To fail gradually in size, quantity, or quality; e.g., the mine has petered out. Also called peter out. Fay petering out The gradual thinning of a vein until it disappears. Statistical Research Bureau Petersen grab In the Petersen (or van Veen) type of grab, two semicircular buckets of varying sizes are hinged along a central axis. The buckets are held apart for lowering from a ship to the bottom by some form of catch. On striking the bottom, this is released so that on hoisting, the buckets move around on their axis, take a bite out of the sediment, and come together to form a closed container. With this configuration, the rate at which the grab hits the bottom affects the bite, and when the ship is drifting, a poor sample may be obtained if the grab does not hit the bottom vertically. See also: grab sampler PETN Abbrev. for pentaerythritol tetranitrate. See also: penthrite Bennett petralite An explosive compounded of ammonium carbonate, nitrated wood or charcoal, and saltpeter. Standard, 2 petrifaction A process of fossilization whereby organic matter is converted into a stony substance by the infiltration of water containing dissolved inorganic matter (e.g., calcium carbonate, silica), which replaces the original organic materials, sometimes retaining the structure. Syn: petrification petrification See: petrifaction petrified moss See: tufa petrified rose

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An aggregate or cluster of tabular crystals of barite, forming chiefly in sandstone, enclosing sandy grains within the crystals; sand cemented by barite with the crystal form of the latter. Syn: barite rosette See also: rosette petrified wood See: silicified wood petroCombining form meaning stone or rock. petrochemical Any of several materials and compounds present in, or derived from, natural gas or crude petroleum by physical refining or by chemical reaction. Bennett petrochemistry a. The study of the chemical composition of rocks. AGI b. The study of the chemistry of petroleum and its products. AGI petrofabrics The study of spatial relations, esp. on a microscale, of the structural-textural units that comprise a rock, including a study of the movements that produced these elements. The units may be rock fragments, mineral grains, or cleavages. petrogenesis A branch of petrology that deals with the origin of rocks. Syn: lithogenesis; petrogeny. CF: genesis petrogenic element An element that is characteristically concentrated in ordinary rock types as opposed to ore deposits. CF: metallogenic element petrogeny See: petrogenesis petrographer Person who is versed in or engaged in petrography, or the study of rocks. Fay 2302

petrographic Pertaining to the study of rocks. Stokes petrographic microscope A microscope specially fitted with optical, esp. polarizers, and mechanical accessories for identifying and studying the properties of minerals in granular form or in thin section. petrographic province A natural region within which some or all of the igneous rocks present certain wellmarked peculiarities in their mineralogical and chemical composition, structure, texture, etc., that set them apart from rocks of other petrographic provinces. Consanguineous, comagmatic. Syn: comagmatic region petrography A general term for the science dealing with the description and systematical classification of rocks, based on observations in the field, on hand specimens, and on thin sections. Petrography is thus wider in its scope than lithology, but more restricted than petrology, which implies interpretation as well as description. Holmes, 2 petroleum coke Cokelike material found in cavities of igneous rocks intrusive into carbonaceous sediments. Tomkeieff petroleum ether A mixture of hydrocarbons boiling from 40 to 60 degrees C; a mixture of low-boiling liquid alkanes. Handbook of Chemistry and Physics, 1 petroleum-oil cannel coal See: oil shale petrology A general term for the study, by all available methods, of the natural history of rocks, including their origins, present conditions, alterations, and decay. Petrology comprises petrography on the one hand, and petrogenesis on the other, and properly considered, its subject matter includes ore deposits and mineral deposits in general, as well as rocks in the more limited sense in which that term is generally understood. Holmes, 2 2303

petrolo-shale See: oil shale petrophysics Study of the physical properties of rock. AGI petrotectonics See: structural petrology petrous Said of a material that resembles stone in its hardness; e.g., petrous phosphates. Little used. AGI petuntze See: china stone petzite An isometric mineral, Ag3 AuTe2 ; metallic; steel gray to iron black; massive; sp gr, 8.7 to 9.02; in gold-bearing telluride veins; may be a significant source of gold and silver. pH The negative logarithm (base 10) of the hydrogen-ion activity. It denotes the degree of acidity or of basicity of a solution. At 25 degrees C, 7 is the neutral value. Acidity increases with decreasing values below 7, and basicity increases with increasing values above 7. ASM, 1 phacellite See: kaliophilite phacolith A concordant intrusive in the crest of an anticline and trough of a syncline; in cross section, it has the shape of a doubly convex lens. Adj: phacolithic. See also: laccolith phanerite

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An igneous rock having the grains of its essential minerals large enough to be seen macroscopically. AGI phaneritic Said of the texture of an igneous rock in which the individual components are distinguishable with the unaided eye, i.e., megascopically crystalline. Also, said of a rock having such texture. CF: aphanitic Syn: macromeritic; phanerocrystalline; phenocrystalline. AGI phanerocrystalline See: phaneritic Phanerozoic That part of geologic time represented by rocks in which the evidence of life is abundant, i.e. Cambrian and later time. CF: Cryptozoic AGI phantom crystal A crystal or mineral aggregate within which an earlier stage of crystallization or growth is outlined by dust, tiny inclusions, or bubbles; e.g., a trigonal scalenohedron of calcite coated with hematite and overgrown with a clear calcite rhombohedron in crystallographic continuity. Syn: ghost crystal phantom horizon a. In seismic reflection prospecting, a line drawn on seismic sections so that it is parallel to nearby dip segments thought to indicate structural attitude. It is used where actual events are not continuous enough to be used alone. AGI b. Horizon on a reflection profile that is obtained by averaging the dips of the reflections within a band, thus indicating the trend of the dip, but not necessarily coinciding with an actual boundary plane. Schieferdecker pharmacolite A monoclinic mineral, CaHAsO4 .2H2 O ; white to gray; forms silky fibers; occurs in the oxidized parts of arsenical deposits. Syn: arsenic bloom pharmacosiderite An isometric mineral, KFe4 (AsO4 )3 (OH)4 .6-7H2 O; crystallizes in cubes or tetrahedra with cubic cleavage; rarely massive; occurs widely as an oxidation product of arsenical ores. Syn: cube ore 2305

phase a. The sum of all those portions of a material system that are identical in chemical composition and physical state. CTD b. A homogeneous, physically distinct portion of matter in a heterogeneous system. AGI c. An interval in the development of a given process; esp. a chapter in the history of the igneous activity of a region, such as the volcanic phase and major and minor intrusive phases. AGI d. A lithologic facies, esp. on a small scale, such as a minor variety within a dominant or normal facies, or a facies of short duration or local occurrence; e.g., a marine phase or a fluviatile phase. AGI phase angle An angle expressing phase or phase difference. Webster 3rd phase-balance relay Relay that protects an electrical system from faults occurring in any phase of a threephase system. Quite often a fault current will not be large enough to trip the overcurrent relay, but will operate the phase-balance mechanism. Coal Age, 3 phase control The process of varying the point within the cycle at which anode conduction is permitted to begin. Coal Age, 1 phase converter A machine for converting an alternating current into an alternating current of a different number of phases and the same frequency. Webster 3rd phase diagram A graph designed to show the boundaries of the fields of stability of the various phases of a system. The coordinates are usually two or more of the intensive variables temperature, pressure, and composition, but are not restricted to these. Syn: equilibrium diagram phase disengagement In solvent extraction or liquid-liquid extraction procedures, allowing the mixture of aqueous liquor and organic solution phases to separate for individual recovery and further treatment. phase disengagement rate 2306

In solvent extraction technology, the rate of disengagement of phases (aqueous and organic carrier). phase displacement The angle by which the amount of difference of phase between two alternating-current magnitudes is expressed. Standard, 2 phase equilibria The study and determination of stable phases present under various conditions of pressure, temperature, and composition according to the Gibbs phase rule; used in the study of mineral genesis. CF: crystallogeny phase inversion In the Convertol process, replacement of the film of water covering a coal particle by a film of oil. BS, 5 phasemeter A device for measuring the difference in phase of two alternating currents or electromotive forces. Webster 3rd phase rule The statement that for any system in equilibrium, the number of degrees of freedom is two greater than the difference between the number of components and the number of phases. It may be symbolically stated as F = (C-P) + 2. See also: mineralogical phase rule phase shifter A device employed to alter the phase of a wave. NCB phase system Any portion of the universe that can be isolated completely and arbitrarily from the rest for consideration of the changes that may occur within it under varied conditions. In a closed system, energy may cross the system boundary, but matter may not. In an open system, both energy and matter may enter or leave as required. An equilibrium system is closed with all phases in their lowest energy states. The variance (degrees of freedom) of an equilibrium system is its number of components minus its number of phases plus two. A steady-state system is open with all phases in their lowest energy states while matter streams through it. Systems may be described by the number of their components; 2307

e.g., unary for one component, binary for two, ternary for three, etc. They are commonly defined in terms of their components; e.g., the system CaO-MgO-SiO2 -H2 O is a quaternary system. phase transformation The inversion of one crystalline assemblage of components from one symmetry to another; e.g., calcite to aragonite. phenacite See: phenakite phenakite A trigonal mineral, Be2 SiO4 ; colorless to yellow, red, or brown; a minor gemstone sparsely found in granite pegmatites. It is sometimes confused with quartz. Not to be confused with fenaksite. Syn: phenacite phengite a. A variety of muscovite having high silica. b. A transparent or translucent stone (probably crystalline gypsum) used by the ancients for windows. phenhydrous a. Applied to certain conditions under which coal was formed, namely those of open waters into which the plant debris was swept from the adjoining land. Tomkeieff b. Refers to vegetable matter deposited under water in contrast to that laid down on a wet substratum. CF: crypthydrous phenocryst A term for large crystals or mineral grains floating in the matrix or groundmass of a porphyry. Syn: inset phenocrystalline See: phaneritic phenol A soluble, crystalline acidic compound; C6 H5 OH ; has a characteristic odor. It is present in coal tar and in wood tar. It is a powerful caustic poison and in a dilute solution, a useful disinfectant. Used chiefly in making resins and plastics, dyes, and 2308

pharmaceuticals (such as aspirin). Syn: benzenol; hydroxybenzene; carbolic acid. Handbook of Chemistry and Physics, 2 phi grade scale A logarithmic transformation of the Wentworth grade scale in which the negative logarithm to the base 2 of the particle diameter (in millimeters) is substituted for the diameter value (Krumbein, 1934); it has integers for the class limits, increasing from -5 for 32 mm to +10 for 1/1,024 mm. The scale was developed specif. as a statistical device to permit the direct application of conventional statistical practices to sedimentary data. See also: Wentworth grade scale Philadelphia rod A leveling rod in which the hundredths of feet, or eighths of inches, are marked by alternate bars of color the width of the measurement. Nichols, 1 phillipite A compact, blue, hydrated copper and iron sulfate, Fe2 Cu(SO4 )4 .12H2 O , produced by decomposition of chalcopyrite. Standard, 2 phillipsite A monoclinic mineral, (K,Na,Ca)1-2 (Si,Al)8 O16 .6H2 O ; zeolite group; commonly occurs in complex twinned crystals; in basalt amydules, in pelagic red clays, in palagonite tuffs, in alkaline saline lakes from silicic vitric volcanic ash, in alkaline soils, and around hot springs in Roman baths. Phleger corer Designed to obtain cores up to about 4 ft (1.2 m) in length, the Phleger corer is utilized where only the upper layers of the sea bottom are to be analyzed. Hunt phloem In coal, the outer conducting part of the central cylinder or vascular tissues. It consists primarily of sieve tubes and companion cells, phloem fibers or bark fibers, stone cells, and parenchymatous cells. Hess phlogopite A monoclinic mineral, K2 Mg6 (Si6 Al2 O20 )(F,OH)4 ; a magnesium-rich end-member of the biotite crystal solution series; mica group; pseudohexagonal with perfect basal cleavage; occurs in crystalline limestones as a product of dedolomitization, in potassium2309

rich ultramafic rocks, as an alteration mineral in sulfur-rich hydrothermal assemblages, and in kimberlites. Syn: magnesium mica; amber mica; brown mica. pH modifier Proper functioning of a cationic or anionic flotation reagent is dependent on the close control of pH. Modifying agents used are soda ash, sodium hydroxide, sodium silicate, sodium phosphates, lime, sulfuric acid, and hydrofluoric acid. Fuerstenau pholerite A claylike mineral closely related to or identical with kaolinite. Fay pholidoide The group of aluminous glauconites grading into normal (ferruginous) glauconite and occurring in sedimentary rocks. Includes skolite and bravaisite. Distinct from pholidolite of Nordenskiold. CF: illite English phonolite The extrusive equivalent of nepheline syenite. The principal mineral is soda orthoclase or sanidine. Other major minerals are nepheline and aegirine diopside, usually with other feldspathoidal minerals such as sodalite or haueyne. Accessories include apatite and sphene. Phonolite is an important ore progenitor, as at Cripple Creek, CO. Syn: clinkstone phosgenite A tetragonal mineral, 4[Pb2 (CO3 )Cl2 ] ; forms stubby crystals; may be massive; adamantine; sp gr, 6.13; a secondary mineral in lead deposits and from action of seawater on lead slags and artifacts; commonly associated with cerussite and anglesite. Syn: horn lead phosphalite Phosphorite that occurs as beds of small concretions resting on clay surfaces or scattered in sands and limestone. AGI phosphate a. n. Any mineral containing essential tetrahedral phosphate, (PO4 )3- , structural entities; e.g., apatite, amblygonite, or monazite. b. A mineral commodity supplying phosphorus, usually for agricultural or chemical purposes. The source materials for phosphate are marine phosphorite and, less commonly, guano and apatite-rich igneous rocks. c. Adj., 2310

phosphatic. Pertaining to or containing phosphates or phosphoric acid; said esp. of a sedimentary rock containing phosphatic minerals, such as phosphatic limestone produced by secondary enrichment of phosphatic material, or a phosphatic shale representing mixtures of primary and secondary phosphate and clay minerals. CF: vanadate phosphate lands In mining law, a leased area for phosphate lands may not exceed 2,560 acres (1,034 ha). A certain expenditure for mine development and operations is required. A royalty of not less than 2% of the gross value of the output must be paid, and an annual rental, similar to that for coal lands, is imposed. Lewis phosphate of lime See: apatite phosphate rock Any rock that contains one or more phosphatic minerals of sufficient purity and quantity to permit its commercial use as a source of phosphatic compounds or elemental phosphorus. About 90% of the world's production is sedimentary phosphate rock, or phosphorite; the remainder is igneous rock rich in apatite. Syn: rock phosphate phosphatic nodule Black to brown, rounded mass, variable in size from a few millimeters to 30 or more centimeters. Usually consists of coprolites, corals, shells, and bones, more or less enveloped in crusts of collophane. Found in many horizons of marine origin. Also covering the ocean floors at many locations around the world. AGI phosphide A compound that is a combination of phosphorus with a metal; e.g., schreibersite, (Fe,Ni)3 P . phosphochalcite See: pseudomalachite phosphophyllite A monoclinic mineral, Zn2 (Fe,Mn)(PO4 )2 .4H2 O ; forms tabular crystals with perfect cleavage; vitreous; colorless to pale blue-green; a secondary mineral from pegmatites; possibly in some oxidized base-metal deposits. 2311

phosphor Any material that has been prepared artificially and has the property of luminescence, regardless of whether it exhibits phosphorescence. CCD, 2; Lee phosphorate a. To combine or to impregnate with phosphorus; as phosphorated oil. Syn: phosphorize b. To make phosphorescent. Standard, 2 phosphor bronze An elastic, hard and tough alloy, composed of 80% to 95% copper, 5% to 15% tin, with phosphorus up to 2.5%. Nelson phosphorescence a. Luminescence in which the stimulated substance continues to emit light after the external stimulus has ceased; also, the light so produced. The duration of the emission is temperature-dependent, and has a characteristic rate of decay. CF: fluorescence; luminescence. Webster 3rd b. A misnomer for the property of emitting light without sensible heat; luminescence. Although light is produced by a biochemical reaction involving phosphorus, bioluminescence is the preferred term. Hy phosphoric acid A clear, colorless, sparkling liquid or a transparent orthorhombic crystal; H3 PO4 (orthophosphoric acid), depending on the concentration and the temperature. At ordinary atmospheric temperature (20 degrees C), the 50% and 75% acids are mobile liquids, the 85% acid is syrupy, and the 100% acid is in crystals; specific gravity, 1.834 (at 18 degrees C); melting point, 42.35 degrees C; boiling point, 260 degrees C; soluble in water and in alcohol; and very corrosive to ferrous metals and alloys. CCD, 2; Handbook of Chemistry and Physics, 2 phosphorite A sedimentary rock with a high enough content of phosphate minerals to be of economic interest. Most commonly it is a bedded primary or reworked secondary marine rock composed of microcrystalline carbonate fluorapatite in the form of laminae; pellets; oolites; nodules; skeletal, shell, and bone fragments; and guano. Aluminum and iron phosphate minerals (wavellite, millisite) are usually of secondary formation. See also: brown rock; bone phosphate; pebble phosphate. AGI phosphorize 2312

See: phosphorate phosphorized copper A general term applied to copper deoxidized with phosphorus. The most commonly used deoxidized copper. ASM, 1 phosphorochalcite See: pseudomalachite phosphorogen A substance that promotes phosphorescence in a mineral or other compound. Hess phosphorus A nonmetallic element of the nitrogen group. Symbol, P. Never found free in nature, but is widely distributed in combination with minerals. An important source is phosphate rock, which contains the mineral apatite. Ignites spontaneously, and is very poisonous; must be kept under water. Used in safety matches, pyrotechnics, pesticides, incendiary shells, smoke bombs, tracer bullets, and fertilizers. Syn: amorphous phosphorus Handbook of Chemistry and Physics, 3 phosphorus copper Copper that contains about 15% phosphorus. Used chiefly as a deoxidizer for molten metals. Henderson phosphorus steel Steel in which phosphorus is the principal hardening element. Fay phosphosiderite A monoclinic mineral, Fe3+ PO4 .2H2 O ; iron may be replaced by aluminum; dimorphous with strengite; isomorphous with metavariscite; forms tabular crystals or reniform crusts; vitreous; occurs in a wide variety of settings where iron and phosphate are in proximity. Formerly called metastrengite, clinostrengite. phosphuranylite An orthorhombic mineral, Ca(UO2 )3 (PO4 )2 (OH)2 .6H2 O ; radioactive; deep yellow; earthy or as crusts or tiny scales; associated with autunite and other secondary uranium minerals, esp. in pegmatites. 2313

photicite Described as altered rhodonite; carbonated rhodonite. Dana, 1 photoelasticity A property of certain transparent substances that enables the presence of strain to be detected by examination in polarized light. If models of complicated engineering structures are made of such a substance, the stress distribution in the structure may be resolved. See also: model analysis; isochromatic lines; stress analysis. Hammond photoelectric cell Broadly, any device in which the incidence of light causes a change in the electrical state. Nelson photofluorography The photography of images produced on a fluorescent screen by X-rays. Varieties include photoradiography, photoroentgenography, miniature radiography. ASM, 1 photogeology The identification, recording, and study of geologic features and structures by means of photography; specif. the geologic interpretation of aerial and space photographs and images and the presentation of the information so obtained. It includes the interpretation of second-generation photographs obtained by photographing images recorded on television-type tubes (the images recording wavelengths outside the visible spectrum). AGI photogeomorphology Study of earth forms as revealed by aerial photographs. photogrammetry The art and science of obtaining reliable measurements from photographic images. Methods utilize horizontal, vertical, and oblique views, with or without the aid of the stereoscopic principle and with or without computer-based image processing and analysis. See also: infrared photography photographic borehole survey

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A method of checking verticality and/or orientation of a long borehole. A compact camera inserted at a known depth takes a photograph of a magnetic needle and/or a clinometer. Instruments have been developed by Oehman, Owen, and Wright. Pryor, 3 photographic interpretation See: photointerpretation photographic-paper recorder A small device for registering photographically the passage of flame. This must not be confused with the photographing of the flame on the manometer record. Rice, 2 photointerpretation The extraction of information from aerial photographs and images for a particular purpose, such as mapping the geologic features of an area. Syn: photographic interpretation photolithotroph Autotrophic microorganism that derives energy to do metabolic work by converting radiant energy into chemical energy and assimilates carbon as CO2 , HCO3- , or CO32(photosynthesis). See also: autotroph photomacrograph See: macrograph photomagnetic borehole surveying A method of borehole surveying, consisting essentially of a timing clock, batteries and light bulb, a floating light-transparent compass, an inclination unit, and a photographic film for recording both the position of the compass and the crosshairs of the inclinometer. The instrument is enclosed in a nonmagnetic casing. See also: multishot gyroscopic instrument Nelson photometric method A dust-sampling method in which samples of dust are collected on filter paper and then placed in a photometer. The instrument shows the intensity of a beam of light after it has passed through the paper, and the fall in intensity is a direct measure of the dust concentration. With dark dust, such as in coal mines, a rough indication of the dustiness may be obtained by comparison of the depth of tone with a graded series of samples that have been calibrated against some other instrument. There are two methods of collecting 2315

samples for photometric estimation: (1) by passing the air through a filter paper, as for gravimetric estimation; or (2) by impingement, as in the konimeter. Spalding photomicrograph A photographic enlargement of a microscopic image such as a petrologic thin section; a type of micrograph. Less-preferred syn: microphotograph. Webster 3rd photomultiplier A sensitive detector of light in which the initial electron current, derived from photoelectric emission, is amplified by successive stages of secondary electron emission. NCB photon A discrete quantity of electromagnetic energy. Photons have momentum but no mass or electrical charge. Lyman photosensitive Term applied to minerals (e.g., chlorargyrite, utenbogaardite) that are visibly injured by light. photostat printing A method of reproducing a drawing on opaque paper by printing from a photographic negative, which enables the original drawing to be enlarged or reduced. Hammond phototheodolite A ground-surveying instrument used in terrestrial photogrammetry, combining the functions of a theodolite and a camera mounted on the same tripod. AGI phototropism The reversible change in color of a substance produced by the formation of an isomeric modification when exposed to radiant energy (such as light). Webster 3rd phragmites peat Peat composed of reed grass and other grasses. Tomkeieff phreatic 2316

Pertaining to ground water. AGI phreatic explosion A volcanic eruption or explosion of steam, mud, or other material that is not incandescent; it is caused by the heating and consequent expansion of ground water due to an underlying igneous heat source. AGI phreatic gas Any of the vapors and gases of atmospheric or oceanic origin which, coming into contact with ascending magma, may provide the motive force for volcanic eruptions. CTD phreatic line See: line of seepage phreatic surface See: water table phreatic water A term that originally was applied only to water that occurs in the upper part of the zone of saturation under water-table conditions (syn. of unconfined ground water, or well water), but has come to be applied to all water in the zone of saturation, thus making it an exact syn. of ground water. AGI phreatic zone See: zone of saturation pH regulator Substance used in flotation processes to control the hydrogen-ion concentration. See also: pH phthanite Siliceous shale. The term is used esp. by European geologists. Also spelled phtanite. AGI phthisis

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Miner's occupational disease, a form of lung consumption associated with or aggravated by work in dusty surroundings, such as badly ventilated underground workings. See also: pneumoconiosis phyllic alteration Hydrothermal alteration typically resulting from removal of sodium, calcium, and magnesium from calc-alkalic rocks, with pervasive replacement of silicates, muting the original rock texture. It is a common style of alteration in porphyry base-metal systems around a central zone of potassic alteration. See also: propylitization phyllite a. A metamorphic rock, intermediate in grade between slate and mica schist. Minute crystals of sericite and chlorite impart a silky sheen to the surfaces of cleavage (or schistosity). Phyllites commonly exhibit corrugated cleavage surfaces. CF: illite; phyllonite. AGI b. A general term for minerals with a layered crystal structure. AGI c. A general term used by some French authors for the scaly minerals, such as micas, chlorites, clays, and vermiculites. phyllite-mylonite See: phyllonite phyllitic cleavage Rock cleavage in which flakes are produced that are barely visible to the unaided eye. It is coarser than slaty cleavage and finer than schistose cleavage. Leet, 1 phyllonite A rock that macroscopically resembles phyllite but that is formed by mechanical degradation (mylonization) of initially coarser rocks (e.g., graywacke, granite, or gneiss). Silky films of recrystallized mica or chlorite, smeared out along schistosity surfaces, and formation by dislocation metamorphism are characteristic. Syn: phyllite-mylonite See also: mylonite gneiss phyllonitization The processes of mylonitization and recrystallization to produce a phyllonite. AGI phylloretin Crystalline hydrocarbon similar to fichtelite and extracted along with fichtelite from fossil pine wood. Tomkeieff 2318

phyllovitrinite Vitrain in which the plant remains are discernible under a microscope. Tomkeieff phyre A suffix used in naming rocks that are porphyritic, such as vitrophyre, orthophyre, or granophyre. physical depletion The exhaustion of a mine or a petroleum reservoir by extracting the minerals. Williams physical geology A broad division of geology that concerns itself with the processes and forces involved in the inorganic evolution of the Earth and its morphology, and with its constituent minerals, rocks, magmas, and core materials. CF: historical geology physical mineralogy That branch of mineralogy which treats of the physical properties of minerals. CF: chemical mineralogy physical oceanography That marine science which treats of the Earth's water mass as a fluid and studies its physical properties of motion, density, temperature, etc. Hy physical shock A state of collapse that interferes with the normal heart action, respiration, and circulation. This condition is probably due to derangement or lack of proper balance within the sympathetic nervous system and may be caused by any number of things, such as serious injury, loss of blood, severe burns, fright, and many others. It is important to look for shock when rendering first aid since it may cause death even when the injury is less serious. Kentucky physics The science, or group of sciences, that treats of the phenomena associated with matter in general, esp. in its relations to energy, and of the laws governing these phenomena, excluding the special laws peculiar to living matter (biology) or to special kinds of matter (chemistry). Physics treats of the constitution and properties of matter, mechanics, 2319

acoustics, heat, optics, electricity, and magnetism. More generally, it includes all the physical sciences. Standard, 2 physiographic province A region of which all parts are similar in geologic structure and which has consequently had a unified geomorphic history; a region whose pattern of relief features or landforms differs significantly from that of adjacent regions. AGI phyteral The term was introduced by G. H. Cady in 1942, to designate plant forms or fossils in coal as distinguished from the material of which the fossils may be composed. Phyterals are identified in general botanical terms that are usually morphological, such as spore coat, sporangium, cuticle, resin, wax, wood substance, bark, etc. The initial composition of the phyterals differed; these or other differences produced during diagenesis may or may not be perpetuated by and during carbonification (coalification). Phyterals are recognized with increasing difficulty in high rank coals. In contrast to macerals which represent a purely petrographical concept, the concept phyteral demands strict correlation with certain organs of the initial plant material. IHCP phytogenous rock Rock formed from plant remains. Tomkeieff phytolith A rock formed by plant activity or composed chiefly of plant remains. The term was applied by Grabau to a large group including coal, peat, lignites, some types of reef limestones, and oolites. AGI phytoplankton The plant life division of plankton, including diatoms and algae. Unattached plants that are at the mercy of the currents. Hy piano wire screen A screen formed by piano wires stretched tightly, lengthwise, on a frame 2 to 3 ft (0.61 to 0.91 m) wide and 4 to 8 ft (1.2 to 2.4 m) high. The screen is set up at an angle of about 45 degrees and crushed material is fed to it from above. The mesh size varies from about 4 to 16. Because there are no cross wires, and because the taut wires can vibrate, there is less tendency for blinding, but some elongated particles inevitably pass the screen. Dodd picacho 2320

A peak or sharply pointed hill or mountain; commonly a volcanic rock. The term is used in desert regions of the Southwestern United States. pick a. Steel cutting point used on a coal-cutter chain. See also: coal-cutter pick b. A miner's steel or iron digging tool with sharp points at each end. It weighs from 3 to 6 lb (1.4 to 1.7 kg) and has a wood handle, fitted to the center or head, from 2 to 3 ft (0.6 to 0.9 m) in length. Syn: miner's pick c. To dress the sides of a shaft or other excavation. d. To remove shale, dirt, etc., from coal. e. To select good ore out of a heap. f. In seismic prospecting, any selected event on a seismic record. AGI pick-a-back conveyor A short conveyor which takes the coal from, and advances with, a face power loader or continuous miner. It delivers the coal onto a gate conveyor over which it runs on a bogey. See also: long piggyback conveyor pick-and-shovel miner See: pick miner Pickard core barrel A double-tube core barrel in X-group sizes. The distinguishing feature of the Pickard barrel is that when blocked, the inner barrel slides upward into the head, closing the water ports and stopping the flow of the circulating liquid; no additional drilling can be done without irreparably damaging the bit until the barrel is pulled and the blocked inner tube is cleared. Long pick boy In bituminous coal mining, a person who carries sharpened picks or bits for coal-cutting machines to the machine operator in underground working places. Also called pick carrier. DOT pick breaker A breaker developed as the mechanical equivalent of the miner's pick. In the modern type, the picks are mounted on alternating arms, the primary and secondary picks being at different spacings so that breaking is performed in two stages. The breaker and plate belt are usually supplied as a standard unit driven from a common motor. Nelson pick carrier 2321

See: pick boy picker a. An employee who picks or discards slate and other foreign matter from coal in an anthracite breaker or at a picking table, or one who removes high-grade ore, iron, or scrap wood from ore as it passes on a conveyor belt to crushers. BCI; DOT b. A mechanical arrangement for removing slate from coal. c. A miner's needle, used for picking out the tamping of a charge that has failed to explode. Syn: piercer pickeringite A monoclinic mineral, MgAl2 (SO4 )4 .22H2 O ; hallotrichite group; forms acicular crystals and tufts; astringent taste; a product of surficial acid sulfate attack on aluminous rocks in mines and arid regions. Syn: magnesia alum picket a. A sighting hub. See also: backsight hub; foresight hub. Long b. A short ranging rod about 6 ft (1.8 m) long. An iron rod, pointed at one end, and usually painted alternately red and white at 1-foot (30.5-cm) intervals; used by surveyors as a line of sight. See also: range pole CTD; Fay picking a. Operation performed between mine and mill in which waste rock, wood, detritus, steel (tramp iron), or any specially separated mineral is removed from the run-of-mine ore material by hand sorting. Usually done during transit of material on belt conveyors, preferably after very large lumps and smalls have been screened off and the ore to be picked has been sufficiently washed to display a true surface. Also done on a picking table, a rotating circular disc around which hand sorters stand or sit to remove part of the ore fed radially from a central point. Picking can also be mechanized. Pryor, 3 b. The falling of particles from a mine roof about to collapse. c. Extracting over a prolonged period an undue proportion of the richest ore from a mine, thus lowering the average grade of the remaining ore reserves; "picking the eyes out" of a mine. d. Rough sorting of ore. Webster 2nd picking belt A continuous conveyor (e.g., in the form of a rubber belt or of a steel apron, steelplate, or link construction) on which raw coal or ore is spread so that selected ingredients may be removed manually. Syn: picking table; picking chute; picking conveyor. BS, 5 picking chute 2322

A chute along which workers are stationed to pick slate from coal. See also: picking belt picking conveyor See: picking belt picking out eyes Mining in which only the high-grade spots are taken out. Hoover picking table A flat, or slightly inclined, platform on which the coal or ore is run to be picked free from slate or gangue. See also: picking belt; picking conveyor. pick lacing The pattern to which the picks are set in a cutter chain. In this respect, it may be a balanced or an unbalanced cutter chain. Pick lacing is important as it has a bearing on the stability of the machine, on dust formation, and even on dangerous sparking. Nelson pickle a. An acid dip used to remove oxides or other compounds from the surface of a metal by chemical action. Lowenheim b. To use such an acid dip. pickling The process of removing scale or oxide from metal objects by immersion in an acid bath to obtain a chemically clean surface prior to galvanizing or painting. Hammond pick machine Coal-cutting machine which acts percussively, and cuts with a large chisel fixed at the end of a piston reciprocated by compressed air in much the same way as a rock drill is operated. Kiser pick mine A mine in which coal is cut with picks. Kiser pick miner In anthracite and bituminous coal mining, a person who: (1) uses hand tools to extract coal in underground workings; (2) cuts out a channel under the bottom of the working 2323

face of coal (undercutting) with a pick, working several feet back into the seam; (3) breaks down a coalface with a pick; (4) bores holes with an augerlike drill for blasting, and inserts and sets off explosives in holes to break down coal; (5) shovels coal into cars and pushes them to a haulageway. Also called hand cutter; hand miner; hand pick miner; pick-and-shovel miner. DOT pick money An earlier practice whereby miners paid a blacksmith for sharpening their picks. Nelson pickrose hoist A small haulage engine used for pulling light loads over short distances; used at junctions, loading points, and haulage transfer points. See also: winch; spotting hoist. Nelson pick tongs Tongs for handling hot metal. Webster 3rd pickup a. Syn. for lift, as applied to hoisting drill rods from a borehole. Long b. An angular crosscut, through which coal is hauled from one entry to another. See also: shoo-fly c. See: geophone; detector. d. Transfer of metal from tools to a part, or from a part to tools, during a forming operation. ASM, 1 e. In Alaska, a gold nugget picked up during mining operations prior to sluicing. pickup test A laboratory procedure used in investigating the floatability of minerals. A few grains, sized between 60 and 120 mesh, are placed, after suitable surface cleansing, under water in an observation cell which is controlled for pH, reagent concentration, temperature, and conditioning time. An air bubble is pressed down on the particles and then raised; the degree and tenacity with which they cling to it are observed. Pryor, 3 pickwork Cutting coal with a pick, as in driving headings. Fay picky poke bar A steel bar, usually of 7/8-in (2.22-cm) stock and about 4 ft (1.2 m) long, with each end sharpened, bent out at an angle of 45 degrees , the bends being 3 to 6 in (7.6 to 15.2 cm) from each end. Hess 2324

picotite A former name for chromian spinel, (Mg,Fe)(Al,Cr)2 O4 . picral An etching reagent consisting of a 2% to 5% solution of picric acid in ethyl alcohol. It may be used for plain carbon and low-alloy steels. Osborne picric acid A yellow crystalline compound, C6 H3 N3 O7 , obtained variously, such as by the action of nitric acid on phenol. It is used in dyeing and is an ingredient in certain explosives. Also called carbazotic acid; chrysolepic acid; trinitrophenic acid. Standard, 2 picrite basalt Olivine-rich basalt, as formed by the settling of olivine in thick flows and sills. Commonly contains 50% or more olivine. AGI picrochromite Magnesium chromite, MgCr2 O4 ; melting point, 2,250 degrees C; sp gr, 4.41. This spinel can be synthesized by heating a mixture of the two oxides at 1,600 degrees C; it is formed (usually with other spinels in solid solution) in fired chrome-magnesite refractories. Picrochromite is highly refractory but when heated at 2,000 degrees C, the Cr2 O3 slowly volatilizes. See also: magnesiochromite picrolite An asbestiform antigorite serpentine. picromerite a. A monoclinic mineral, K2 Mg(SO4 )2 .6H2 O ; forms highly soluble masses or crusts around fumaroles; also a rare, advanced desiccation constituent of marine evaporites. Formerly called schoenite. b. A mineral group including boussingaultite, cyanochroite, mohrite, nickel-boussingaultite, and picromerite. picture A screen to shelter workers from falling water. Zern Pidgeon process 2325

A process for the production of magnesium by the reduction of magnesium oxide with ferrosilicon. ASM, 1 pie A local term for an intermediate pack without supporting walls. TIME piecemeal stoping A process by which magma eats into its roof by engulfing relatively small isolated blocks, which presumably sink to depth where they are assimilated. See also: magmatic stoping piece weight See: effective piece weight piecework The performance of underground work on the basis of an agreement between a miner and the mine manager. Payment may be made by the yard of advance of a heading or tunnel or per ton or cubic yard of coal or ore removed. In ripping work, payment may be made by the yard advance of excavation to a specified width and height; strip packing may be built at a certain sum per yard advance or cubic yard of filling. See also: contract work; yardage. Nelson piedmont Adj. Lying or formed at the base of a mountain or mountain range; e.g., a piedmont terrace or a piedmont pediment.---n. An area, plain, slope, glacier, or other feature at the base of a mountain; e.g., a foothill or a bajada. In the United States, the Piedmont is a plateau extending from New Jersey to Alabama and lying east of the Appalachian Mountains. Etymol: from Piemonte, a region of NW Italy at the foot of the Alps. AGI piedmont alluvial plain See: bajada piedmontite See: piemontite piedmont plain See: bajada 2326

piedmont scarp A small fault scarp at the foot of a mountain range and essentially parallel to the range. AGI piel An iron wedge for piercing stone. Standard, 2 piemontite A monoclinic mineral, Ca2 (Al,Mn,Fe)3 (OH)O(Si2 O7 )(SiO4 ) ; epidote group; less common than epidote; occurs in a variety of environments: low-grade regional metamorphic rocks, manganese deposits, and some intermediate to silicic volcanic rocks, perhaps due to metasomatism. Syn: manganepidote; piedmontite. CF: withamite pier A rectangular or sometimes circular form of column, constructed usually of concrete, hard brickwork, or masonry, and designed to support heavy concentrated loads from arches or a bridge superstructure. Hammond pier cap The upper or bearing part of a bridge pier; usually made of concrete or hard stone; designed to distribute concentrated loads evenly over the area of the pier. Hammond piercement Salt plug that rises and penetrates rock formations to shallow depths. Wheeler, R.R. piercement dome See: diapir piercement fold See: diapir piercer A blasting needle. See also: picker piercing 2327

A prospecting method used in soft soil free from stones, in which small drivepipes are used to secure samples of underlying material or to determine the thickness of the soil. Lewis pier dam Dam or jetty to influence current. CF: weir pietra della raja It. A fine-grained Permian sandstone suitable for sawing and finishing. Hess piezocrystallization Crystallization of a magma under pressure, such as pressure associated with orogeny. AGI piezoelectric axis One of the directions in a crystal in which either tension or compression will cause the crystal to develop piezoelectric charges. Gaynor piezoelectric detector A type of detector that depends upon the piezoelectric effect by which an electric charge is produced on the faces of a properly cut crystal of certain materials, particularly quartz and Rochelle salt, when the crystal is strained. The detector is constructed from a pile of such crystals with intervening metal foil to collect the charge. An inertia mass is mounted on the top of the crystal stack that is included in an electronic circuit. AGI piezoelectricity The property exhibited by some asymmetrical crystalline materials which when subjected to strain in suitable directions develop electric polarization proportional to the strain. Inverse piezoelectricity is the effect in which mechanical strain is produced in certain asymmetrical crystalline materials when subjected to an external electric field; the strain is proportional to the electric field. Quartz is an industrially important example. Hunt piezometer An instrument for measuring pressure head; usually consisting of a small pipe tapped into the side of a closed or open conduit and flush with the inside; connected with a pressure gage, mercury, water column, or other device for indicating head. See also: manometer 2328

piezometric surface See: potentiometric surface pig a. A crude casting of metal convenient for storage, transportation, or melting; esp. one of standard size and shape for marketing run directly from the smelting furnace. CF: ingot b. A mold or channel in a pig bed. Webster 3rd c. A heavily shielded container (usually lead) used to ship or to store radioactive materials. d. An air manifold having a number of pipes which distribute compressed air coming through a single large line. Nichols, 1 pig and ore process Modification of the open-hearth process of steel manufacture with pig iron and iron ore as the charge. Bennett pig and scrap process Modification of the open-hearth process of steel manufacture with pig iron and steel as the charge. Bennett pig bed A series of molds for iron pigs, made in a bed of sand. Connected to each other and to the taphole of the blast furnace by channels, along which the molten metal runs. CTD pig caster Person who pours molten metal into hand ladles, and from ladles into molds to form ingots. DOT pigeonhole a. A room driven directly into a coal seam from the edge of a strip pit. b. Any small poorly equipped coal mine. c. A hole in the shaft house floor through which the bucket or skip is raised or lowered. Hess d. An opening left at the meeting of two sections of arch work, permitting the workers to close the arch and to come out. The pigeonhole itself is closed from below. Stauffer pigeonhole checker An arrangement of checkerbrick such that each course of brick is laid in spaced parallel rows with the brick end to end; each alternate course above and below has its parallel rows at right angles to the intervening course. ARI 2329

pigeonite A monoclinic mineral, (Mg,Fe,Ca)(Mg,Fe)Si2 O6 ; pyroxene group; crystallographically distinct from augite; occurs only in quickly chilled lavas. CF: augite pig foot a. An iron clamp shaped like a pig's foot used to attach the jack to the feed chain of a continuous electric coal cutter. Fay b. A pipe jack with a pig foot at one end. Fay Piggot corer A device for sampling bottom sediments. A core barrel is driven into unconsolidated material by an explosive charge. AGI piggyback conveyor See: long piggyback conveyor pig handler A laborer who removes metal pigs from molds manually and stamps heat numbers on pigs with hammer and punch. DOT pig lead Commercial lead in large oblong masses or pigs. pigment mineral A mineral having economic value as a coloring agent. The most important are the red and yellow ochers and brown sienna, which consists of iron oxides with some impurities, and the brown umbers in which manganese oxide is also present. When the iron-oxide content is high the term oxide is used in preference to ocher. AGI; Nelson pig metal Metal, such as brass or copper, in its first rough casting. Standard, 2 pigotite A salt of alumina and organic acid, 4Al2 O3 .C12 H10 O8 .27H2 O ; formed on the surface of granite under the influence of wet vegetation. Tomkeieff pigsticker 2330

A person delegated to the duty of punching or knocking pig iron out of chills or molds at a blast-furnace or pig-casting machine. Fay pigsty Timber support used in stopes to hold up the roof, consisting of a square frame of chocked round timbers and filled with waste rock. See also: cog pigsty timbering Hollow pillars built up of logs laid crosswise for supporting heavy weights. See also: cribbing pig tailer A laborer who helps a pusher to push loaded mine cars over long distances and up inclines where mechanical or mule haulage is not used. Also called helper-up. DOT pike A term used in England for any summit or top of a mountain or hill, esp. one that is peaked or pointed. Also, a mountain or hill having a peaked summit. AGI Pike process A method for the direct production of steel by passing reducing gases over iron oxide ore, carburizing the reduced ore, and alloying it in an electric furnace. Thus, a reducing gas, heated to 900 degrees C is passed over iron oxide ore to produce metallic iron and spent gas. The carburized, partially reduced metal is melted, reduced, and alloyed in the electric furnace. Osborne piking See: cobbing pilarite An aluminous variety of chrysocolla. Standard, 2 pile a. A timber, steel, or reinforced concrete plate or post that is driven into the ground to carry a vertical load (bearing pile) or a horizontal load from earth or water pressure (sheet pile). Nelson b. A spiked or sharped-edged plank, beam, or even pipe or girder that is forced forward or downward (sinking) into running ground with a view to 2331

support. Mason c. A stack of ore or stones. Gordon d. A prop of timber. Gordon e. Long thick laths, etc., answering in shafts in loose or quick ground, the same purpose as spills in levels, piles being driven vertically. pile dam A dam made by driving piles and filling the interstices with stones. The surfaces are usually protected with planking. pile drawer See: pile extractor pile driver a. A machine for driving down piles; usually consisting of a high frame with appliances for raising and dropping a pile hammer or for supporting and guiding a steam or air hammer. Also called pile engine. Webster 3rd b. An operator of a pile driver. Webster 3rd pile extractor A sheet piling extractor that works on the same principle as the piledriving hammer, except that the force of the blow is upward rather than down. Carson, 1 pile group A number of piles driven or cast in situ, will sustain a much heavier load than a single pile can carry, esp. when connected by a pile cap. Hammond pilehammer This may be a drophammer, a steam hammer, or a diesel hammer of which the last two are completely automatic. Steam hammers are also able to operate on compressed air. See also: jetting pile head The top of a precast concrete pile, protected during driving by packing under a pile helmet and sometimes by a timber dolly. The top of a timber pile is protected by a driving band. Hammond pile helmet

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A cast-steel cap covering and protecting the head of a concrete pile during driving. See also: drophammer pile sinking A method of sinking a circular or rectangular shaft through 20 to 30 ft (6.1 to 9.1 m) of sand or mud at the surface. It cannot be used for greater depths as each ring of piles reduces the inside dimensions of the shaft. See also: pile; piling. Nelson piling A structure or group of piles. See also: cofferdam pill A loosely rolled cylinder of burlap and 1/4-in-mesh (0.6-cm-mesh) hardware cloth pushed down into a borehole ahead of a string of drill rods to the point where a large crevice or small cavity has been encountered. At this point the cylinder tends to unroll partially, forming a mat that acts as a barrier against which other hole-plugging agents may collect and help seal off the opening. Long pillar a. A column of coal or ore left to support the overlying strata or hanging wall in a mine, generally resulting in a "room and pillar" array. Pillars are normally left permanently to support the surface or to keep old workings water tight. Coal pillars, such as those in pillar-and-stall mining, are extracted at a later period. Syn: stump See also: barrier pillar; shaft pillar. b. A block of ore entirely surrounded by stoping, left intentionally for purposes for ground control or on account of low value. Spalding c. A column of rock remaining after solution of the surrounding rock. See also: hoodoo pillar-and-breast A system of coal mining in which the working places are rectangular rooms usually five or ten times as long as they are broad, opened on the upper side of the gangway. The breasts usually from 5 to 12 yd (4.6 to 11.0 m) wide, vary with the character of the roof. The rooms or breasts are separated by pillars of solid coal (broken by small cross headings driven for ventilation) from 5 to 10 yd (4.6 to 9.1 m) or 12 yd (11 m) wide. The pillar is really a solid wall of coal separating the working places. When the object is to obtain all the coal that can be recovered as quickly as possible, the pillars are left thin; but where this plan is likely to induce a crush or squeeze that may seriously injure the mine, larger pillars are left and after the mine has been worked out, the pillars are "robbed" by mining from them until the roof comes down and prevents further working. In the steeply inclined seams of the anthracite regions the pillar-and-breast system is 2333

employed by working the bed in "lifts". Also called pillar-and-stall; post-and-stall; bordand-pillar. Syn: board-and-pillar; board-and-wall. Fay pillar-and-chamber A pillar method of working often adopted in extracting a proportion of thick deposits of salt or gypsum. The method may be adopted where the value of the mineral in the pillars is less than the cost of setting artificial supports. Nelson pillar-and-room A system of mining whereby solid blocks of coal are left on either side of miner's working places to support the roof until first-mining has been completed, when the pillar coal is then recovered. See also: room-and-pillar pillar-and-stall a. A system of working coal and other minerals where the first stage of excavation is accomplished with the roof sustained by coal or ore. See also: pillar-and-breast; postand-stall. b. One of the earliest methods of working coal seams in Great Britain. It is employed in thick seams and where valuable surface buildings require protection from damage by subsidence. A number of narrow roadways are driven in the coal seam to a predetermined boundary. There are two sets of roadways, driven at right angles to each other, and thus the seam is divided into a large number of square or rectangular pillars. These pillars are extracted at a later period. The driving of the narrow roadways is termed working the whole while pillar working is known as working the broken. The width of the roadways and their distance apart are governed by the thickness and nature of the coal seam and the type of roof and floor. The main headings are driven forward and connected at intervals by crosscuts or stentons for ventilation and as a second exit. The bords are driven off the main headings at fixed distances apart, and are connected at intervals by walls. The width of the main headings, crosscuts, and bords varies from 3 to 5 yd (2.7 to 4.6 m). The bords are driven from 15 to 60 yd (13.7 to 54.9 m) apart. The walls are about 2 to 3 yd (1.8 to 2.7 m) wide and driven at similar or greater intervals according to the size of pillars to be formed. Modern pillar-and-stall mining is highly mechanized. See also: crosscut; mechanized heading development; stenton. Also called bord-and-pillar. Nelson pillar boss In bituminous coal mining, a person who supervises the work of robbers in removing pillars of coal that were left to support the roof of working places during mining operations. Syn: rib boss pillar burst 2334

Failure of remnants, promontories, as well as pillars, by crushing. Spalding pillar caving Removal of ore from a series of stopes or rooms, leaving pillars between. Eventually the pillars are forced or allowed to cave under the weight of the roof. pillar coal Coal secured in pillar robbing. Fay pillar drive A wide irregular drift or entry, in firm dry ground, in which the roof is supported by pillars of natural earth or by artificial pillars of stone, without using timber. Fay pillar extraction The recovery or working away of the pillars of coal that were left during the first operation of working in the pillar-and-stall method. Also called pillar mining. See also: jenkin; jud; pillar robbing; pillar extraction. Nelson pillaring back The operation of extracting coal pillars, on the retreating system, in a pillar method of working. Nelson pillar line a. The line along which pillars are being mined. b. Air currents which have definitely coursed through an inaccessible abandoned panel or area or which have ventilated a pillar line or a pillared area, regardless of the methane content or absence of methane in such air. pillar man A person who builds stone packs in mine workings. See also: pack builder pillar methods of working Methods of working coal seams, which have been given different names in different coalfields, such as stoop-and-room in Scotland; bord-and-pillar in Durham, England; and single and double stalls in South Wales. There are many modifications of pillar mining, but in general, there are two stages: (1) the driving of narrow roadways and thus forming a number of coal pillars, and (2) the extraction of the pillars--often on the retreating 2335

system. Pillar methods of mining are widely used in the United States, while the longwall method is favored in Great Britain. Pillar methods also are used for working stratified deposits of ironstone, rock salt, slate, and other layered minerals. Nelson pillar mining system Any of several systems, including the room-and-pillar system, the block system, and the bord-and-pillar system. Woodruff pillar recovery Mining of pillars during retreat mining to increase the overall recovery of the reserve. pillar road a. Roadway formed in coal pillars. Nelson b. Working road or incline in pillars having a range of longwall faces on either side. Fay pillar robber See: robber pillar robbing a. The systematic removal of the coal pillars or ore between rooms or chambers to regulate the subsidence of the roof. Also called pillar drawing. Fay b. The removal of ore pillars in sublevel stoping or slicing. See also: sublevel stoping c. Formerly, in pillarand-stall mining, the coal pillars left were too small, and miners were satisfied to gain some coal by robbing the pillars, usually from middle portions, the remaining coal being too dangerous to extract. Nelson pillar robbing and hand filling See: sublevel stoping pillar split An opening or crosscut driven through a pillar in the course of extraction. pillar strength The formula for pillar strength can be expressed as follows: S = C (L/T) 1/2 where the coefficient, C, is directly dependent upon friction, L is the least pillar width, and T is the thickness. Coal Age, 3 2336

pillar working Working coal in much the same manner as with the pillar-and-stall system. pillow A rock texture characterized by piles of lobate, pillow-shaped masses; individual pillows range up to several meters across; typical of basalt that has erupted under an appreciable depth of water. pillow block A metal-cased rubber block that allows limited motion to a support or thrust member. Nichols, 1 pillow lava A general term for lava that exhibits pillow structure, mostly basalts and andesites that erupted and flowed under water. The ocean floor sodium-rich basalts known as spilites are commonly pillowed. pillow structure A structure, observed in certain extrusive igneous rocks, that is characterized by discontinuous pillow-shaped masses ranging in size from a few centimeters to a meter or more in greatest dimension (commonly between 30 cm and 60 cm). The pillows are close-fitting, the concavities of one matching the convexities of another. The spaces between the pillows are few and are filled either with material of the same composition as the pillows, with clastic sediments, or with scoriaceous material. Grain sizes within the pillows tend to decrease toward the exterior. Pillow structures are considered to be the result of subaqueous extrusion, as evidenced by their association with sedimentary deposits, usually of deep-sea origin. See also: pillow lava; mammillary structure. AGI pilot a. A cylindrical steel bar extending through and about 8 in (20 cm) beyond the face of a reaming bit. It acts as a guide that follows the original unreamed part of the borehole and hence forces the reaming bit to follow and be concentric with the smaller-diameter, unreamed portion of the original borehole. Syn: reaming pilot Long b. A cylindrical diamond-set plug, of somewhat smaller diameter than the bit proper, set in the center and projecting beyond the main face of a noncoring bit. See also: pilot bit; stinger. Long pilotaxitic

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Said of the texture of the groundmass of a holocrystalline igneous rock in which lathshaped microlites (typically plagioclase) are arranged in a glass-free mesostasis and are generally interwoven in irregular unoriented fashion. CF: trachytic pilot bit A noncoring bit with a cylindrical diamond-set plug of somewhat smaller diameter than the bit proper set in the center and projecting beyond the main face of the bit. See also: plug bit; drag bit. Long pilot bob The weight attached to a shaft plumbline for the purpose of lowering the line down the shaft. BS, 7 pilot burner A small burner kept lighted to rekindle the principal burner when desired (as in a flash boiler). The light so maintained is called a pilot light or pilot flame. Webster 3rd; Fay pilot drill A small drill used to start a hole in order to insure a larger drill running true to center. Crispin pilot hole a. A small hole drilled ahead of a full-sized, or larger borehole. Long b. A borehole drilled in advance of mine workings to locate water-bearing fissures or formations. Long c. A small tunnel driven ahead of, and subsequently enlarged to the diameter required in the following full-size tunnel. Long pilot-hole cover See: cover pilot lamp A small electric bulb that lights when power is turned on in a circuit. Hammond pilot method The method of excavating a tunnel by driving a small tunnel ahead, and then enlarging its dimensions. 2338

pilot plant A small-scale processing plant in which representative tonnages of ore can be tested under conditions which foreshadow (or imitate) those of the full-scale operation proposed for a given ore. Pryor, 4 pilot reamer An assemblage of a pilot, a pilot reaming bit, and a reaming barrel. See also: pilot; pilot reaming bit. Long pilot reaming bit A box-threaded, diamond-set, annular-shaped bit designed to be coupled to a pilot and used to ream a borehole to a specific casing size. See also: pilot pilot sampling The taking of preliminary samples of a mineral deposit to study its mode of occurrence and its detailed structure. Syn: reconnaissance sampling Nelson pilot sequence Sequence control by means of a pilot cable is effected by means of a low-voltage supply from one contactor panel to the next, or by means of a line voltage pilot cable. Each contactor has an auxiliary contact that controls the supply to the next contactor. In the low-voltage system, the secondary of each potential transformer is earthed at the preceding panel through an auxiliary switch which closes with the contactor. Until these secondary potential transformer circuits are completed, by closing the auxiliary contact, the next conveyor cannot start. See also: sequence starting pilot shaft See: pilot tunnel pilot tunnel A small tunnel or shaft excavated in the center, and in advance of the main drivage, to gain information about the ground and create a free face, thus simplifying the blasting operations. Nelson pilot valve a. A small balanced valve, operated by a governor or by hand, which controls a supply of oil under pressure to the piston of a servometer or relay connected to a large control 2339

valve, which it is desired to operate. Also called relay valve. CTD b. In a compressor, an automatic valve that regulates air pressure. Nichols, 1 pilot wedge A half-cylinder member, about 5 in (12.7 cm) long, coupled to the lower end of a HallRowe deflection wedge, by means of which the deflection wedge may be oriented in a specific manner in reference to a matching half-cylinder surface on the upper end of the wedge (drive wedge). This is driven into the wooden plug placed about 8 ft (2.4 m) below the point in a borehole where a deflection is to be made. Also called wedge pilot. Long Pilz furnace A circular or octagonal shaft furnace, maintaining or increasing its diameter toward the top, and having several tuyeres; used in smelting lead ores. Fay pimelite A massive or earthy, apple-green, nickel-bearing phyllosilicate; probably willemseite or kerolite having disordered stacking; (Ni,Mg)6 Si8 O20 (OH)4 . pimple metal Crude copper matte of about 78% copper, obtained from the smelting of sulfide copper ores. Bennett pin See: wedge rock pinacoid An open crystal form consisting of two parallel faces. AGI pinch a. A marked thinning or squeezing of a rock layer; e.g., a coming-together of the walls of a vein, or of the roof and floor of a coal seam, so that the ore or coal is more or less completely displaced. See also: nip CF: make; want. Standard, 2 b. A thin place or a narrow part of, an orebody; the part of a mineral zone that almost disappears before it widens out in another place to form an extensive orebody. AGI c. The binding action caused when drillhole walls close in before casing is emplaced, resulting from failure of soft or plastic formations. Long 2340

pinchbar A kind of crowbar with a short projection and a heel or fulcrum at the end; a pinch. Used to pry forward heavy objects. Standard, 2 pinched Where a vein narrows, as if the walls had been squeezed in. Where the walls meet, the vein is said to be pinched out. See also: pinching out; pinch. pinching out Where a lode or stratum narrows down and disappears. See also: pinch BCI pinch out To taper or narrow progressively to extinction; to thin out. AGI pinder concentrator A revolving table on which are tapering spiral copper cleats on a linoleum cover. The tailings are washed over the riffles and off the edge, while the concentrates are delivered at the end of the riffles. Liddell pineapple a. A cast roller, designed to keep the haulage rope centered between rail tracks. Spiral grooves on the sides return a straying rope to the central grooves. Works in one direction only. Pryor, 3 b. See: line oiler pine tar Very viscous; dark brown to black; liquid or semisolid; strong characteristic odor; sharp taste; translucent in thin layers; hardens with aging; sp gr, 1.03 to 1.07; boiling point, ranges from 240 to 400 degrees C; soluble in alcohol, ether, chloroform, acetone, glacial acetic acid, fixed and volatile oils, and sodium hydroxide; and insoluble in water. Chief constituents are complex phenols; also present are turpentine, rosin, toluene, xylene, and other hydrocarbons. Used in flotation. CCD, 2 ping An acoustic pulse signal projected by an echo-ranging transducer. Hy pinguite 2341

A former name for nontronite. See also: nontronite pinion Smaller of a pair of toothed wheels, e.g., the pinion geared to the driven crown wheel of a ball mill. Pryor, 3 pinion gear A drive gear that is smaller than the gear it turns. Nichols, 1 pinite A compact, fine-grained, generally impure mica near muscovite in composition; dullgray, green, or brown; derived from the alteration of other minerals, esp. cordierite, nepheline, scapolite, spodumene, and feldspar. pinnacle a. Any high tower or spire-shaped pillar of rock, alone or cresting a summit. A tall, slender, pointed mass; esp., a lofty peak. AGI b. A sharp pyramid or cone-shaped rock under water or showing above it. AGI c. In alluvial mining, a spine or pillar in limestone bedrock of an irregular and serrated type, in which it is difficult for dredge buckets to work. Pryor, 3 pinned coupling A drill-rod coupling that has been permanently attached to the body of the rod by a metal dowel (or pin) driven into a small hole drilled at the point in the rod where the coupling is screwed into the body of the rod. Long pinnel a. Boulder clay, from Cumberland, Northumberland, and Lancashire, England, and North Wales. Arkell b. Coarse gravel or sandstone conglomerate. Arkell pin puller A laborer who removes studs from aluminum reduction pots by operating a motor-driven hydraulic jack. DOT pintadoite

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a. A vanadium ore. Osborne b. A mineral, Ca2 V2 O7 .9H2 O ; green; forms watersoluble efflorescences; associated with uranium-vanadium deposits of the Colorado Plateau. pin thread A thread on the outside surface of a cylindrical or tubular member. Syn: male thread pin timbering A roof support method following two basic principles: (1) that of drilling holes vertically or at an angle into the roof and anchoring roof bolts into a strong firm structure above the lower weak layers, thereby suspending the weak roof on bolts from the strong roof above; and (2) the binding of several layers of weak strata into a beam strong enough to support its weight across the working place. The advantage of pin timbering is that support can be provided at the face without posts being in the way of equipment and more freedom is provided for shuttle cars and other equipment in tramming. See also: timbering; roof bolting. Kentucky pintle A vertical pin fastened at the bottom that serves as a center of rotation. Nichols, 1 pintle hook A towing device consisting of a fixed lower jaw, a hinged and lockable upper jaw, and a socket between them to hold a tow ring. Nichols, 1 pin-to-box The currently accepted term for a coupling, one end of which is threaded on the outside (pin) and the opposite end threaded on the inside (box). Formerly designated as a maleto-female coupling. Long pin-to-pin The currently accepted term for a coupling, both ends of which are threaded on the outside. Formerly designated as a male-to-male coupling. Long pin-type slat conveyor Two or more endless chains to which crossbars are attached at spaced intervals, each having affixed to it a series of pointed rods extending in a vertical plane on which work is carried. Used principally in spraying or washing operations where the least amount of area of the product is contacted. 2343

pion An elementary particle; the contraction of pi-meson. The mass of a charged pion is about 273 times that of an electron. An electrically neutral pion has a mass 264 times that of an electron. Lyman pioneer bench The first bench in a quarry which is blasted out. It is usually at the top of the rock to be quarried. pioneer road A primitive, temporary road built along the route of a job, to provide means for moving equipment and workers. Nichols, 1 pioneer wave U.K. The advance vibration set up by a coal dust explosion. See also: advance wave; shock wave. Nelson piotine See: saponite pipe a. A cylindrical, more or less vertical orebody. Syn: chimney; ore pipe; shoot; stock. AGI b. A vertical conduit through the Earth's crust; e.g., a kimberlite pipe of South Africa, through which magmatic materials have passed. It is usually filled with volcanic breccia and fragments of older rock. As a zone of high permeability, it is commonly mineralized. AGI c. A tubular cavity from several centimeters to a few meters in depth, formed esp. in calcareous rocks, and often filled with sand and gravel; e.g., a vertical joint or sinkhole in chalk, enlarged by solution of the carbonate material and filled with clastic material. See also: piping AGI d. The name given to the fossil trunks of trees found in coalbeds. Fay pipe bit A bit designed for attachment to standard coupled pipe for use in securing the pipe in bedrock. Can be set with diamonds or other abrasive materials. Long pipe clamp

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a. A device similar to a casing clamp, used in the same manner on pipe as a casing clamp is used on casing. See also: casing clamp b. A pipe wrench constructed like a parmalee wrench. Long pipe clay a. Originally a clay suitable for making tobacco pipes, but the term is now used to include any white-burning plastic clay. Nelson b. A mass of fine clay, generally of lenticular form, found embedded in or below a placer gravel bank. pipe coil A device which measures only the density of the magnetic components of a slurry. This electromagnetic sensing unit is mounted on a section of rubber or stainless-steel pipe which is installed as a section of the slurry-carrying pipeline. All components are exterior to the pipe, and there is no obstruction to flow. The pipe coil is used widely in magnetic taconite and heavy-media plants. By combining this device with other instruments, it is possible to continuously measure the ore-to-media ratio. Nelson pipe coupling An internally threaded, short, sleevelike member of ordinary steel used to join lengths of pipe. Sometimes incorrectly called pipe collar; pipe sleeve. Long pipe cutter A tool for cutting wrought iron or steel pipes. The curved end which partly encircles the pipe carries one or more cutting disks. Crispin piped air Air conducted to workings or a tunnel face through air pipes. See also: auxiliary ventilation pipe drivehead a. A drivehead that is coupled to a pipe. See also: drivehead Syn: drive collar b. Extra thick walled pipe or casing coupling against which the blow of a drive block is delivered when driving or sinking drivepipe or casing. Long c. An oversize rod or casing coupling on which the blows of a drive block are delivered when casing is being driven or an attempt is being made to jar loose stuck casing or a drill-rod string. Long d. Incorrectly used as a synonym for drive shoe; drive hammer. Long pipe elevator 2345

A device similar to a casing elevator, used to raise and lower outside-coupled pipe in a borehole. Long pipe factor a. Correction made when drilling running ground, alluvial gravels, and sands. The volume actually extracted over a measured depth is compared with that which would be obtained over the true drill pipe area and distance, any discrepancy being due to inrush of sands or forcing out of sand by the pumping action during drilling. Pryor, 3 b. The assumed cross-sectional area of a length of borehole when estimating the in situ volume of a core sample. Also called pipe constant. Nelson pipe fitting A general term referring to any of the ells, tees, various branch connectors, etc., used in connecting pipes. Crispin pipe friction The drag created on the outside of a pipe being driven into overburden material, which presses and rubs against the outside surface of the pipe and its couplings. See also: skin friction pipe grab A clutch for catching and raising a well pipe. Standard, 2 pipe jack An iron pipe with a clamp or pigfoot on one end and a curved point on the other. It is wedged between the floor and roof of a mine room to hold the feed chain of a continuous electric coal mining machine. Fay pipeline transport Long distance pipeline used for hydraulic transport of coal, gilsonite, copper concentrates and similar materials. See also: hydraulic transport pipeman a. A person engaged in laying or repairing pipelines. Also called pipefitter. BS, 10 b. Mine worker who repairs, lengthens, and maintains the pipelines for air and water in mines. Stoces c. A worker in charge of a pipe, esp. in hydraulic mining. Webster 2nd pipe prover 2346

An apparatus for testing the tightness of a pipeline or system, usually by hydraulic pressure. Standard, 2 piper Sometimes applied to a blower of gas in coal mines. Nelson pipe sampler A device for sampling a pile of ore, consisting simply of a small iron pipe that is driven into the pile and which, when withdrawn, brings a core of ore with it. pipe sampling Sampling by means of a drivepipe in accumulations of crushed residues or of material where the larger pieces are not usually greater than 2 in (5.1 cm). The advancing end of the pipe is generally sharpened to provide a cutting edge, and sometimes contracted in diameter so that material once entered will not readily fall out when the pipe is lifted. Also called gun sampling. See also: drivepipe pipestone See: catlinite pipette analysis The size analysis of fine-grained sediment made by removing samples from a suspension with a pipette. AGI pipette method A method for the determination of particle size. See also: Andreasen pipette piping a. In hydraulic mining, discharging water from nozzles at auriferous gravel. b. The act or process of driving standpipe, drivepipe, or casing into and through overburden. Long c. Erosion by percolating water in a layer of subsoil, resulting in caving and in the formation of narrow conduits, tunnels, or pipes through which soluble or granular soil material is removed; esp. the movement of material, from the permeable foundation of a dam or levee, by the flow or seepage of water along underground passages. See also: water creep AGI d. The flow of water under or around a structure built on permeable foundations that will remove material from beneath the structure. Nelson e. The tubular depression caused by contraction during cooling, on the top of iron and steel ingots. See also: pipe 2347

piracy Stream piracy. pirssonite An orthorhombic mineral, Na2 Ca(CO3 )2 .2H2 O; forms colorless to white short prisms or tablets; in nonmarine evaporites, particularly the Green River oil shales in Wyoming, and Borax Lake, CA. pisanite A blue to green cuproan melanterite (Fe,Cu)SO4 .7H2 O . pisolite a. A sedimentary rock, usually a limestone, made up chiefly of pisoliths cemented together; a coarse-grained oolite. Syn: peastone b. A term often used for a pisolith, or one of the spherical particles of a pisolite.---Etymol: Greek pisos, pea. CF: oolite c. An individual unit in a mass of accretionary lapilli. AGI pisolith One of the small, round or ellipsoidal accretionary bodies in a sedimentary rock, resembling a pea in size and shape, and constituting one of the grains that make up a pisolite. It is often formed of calcium carbonate, and some are thought to have been produced by a biochemical algal-encrustation process. A pisolith is larger and less regular in form than an oolith, although it has the same concentric and radial internal structure. The term is sometimes used to refer to the rock made up of pisoliths. CF: oolith pisolitic tuff An indurated pyroclastic deposit composed chiefly of accretionary lapilli or pisolites. AGI pistacite A pistachio-green ferric-iron-rich variety of epidote. Also spelled pistazite. pistol pipe In metalworking, the tuyere of a hot-blast furnace. Fay piston 2348

The working part of a pump, hydraulic cylinder, or engine that moves back and forth in the cylinder; it is generally equipped with one or several rings or cups to control the passage of fluid. It ejects the fluid from the cylinder, as in a pump, or receives force from the fluid, which causes a reciprocating motion, as in an engine. Long piston corer An oceanographic corer containing a piston inside the cylinder which reduces friction by creating suction. There are several varieties, including the Ewing corer, the Mackereth sampler, and the Kullenberg corer. CF: gravity corer piston drive-sampler See: piston sampler piston sampler A drive sampler equipped with either a free or a retractable-type piston that retreats up into the barrel of the sampler in contact with the top of the soil sample as the sampler is pressed into the formation being sampled. CF: drive sampler piston speed Total feet or meters of travel of a piston in 1 min. Nichols, 1 piston-type sampler See: piston sampler piston-type washbox See: plunger-type washbox pit a. Depression produced in a metal surface by nonuniform electrodeposition or by corrsion. Lowenheim b. Excavation to hold quantities of water and drilling fluids. Wheeler, R.R. c. So. Wales. Long, open-air fire for converting coal into coke for blastfurnace purposes. Fay d. A mine, quarry, or excavation worked by the open-cut method to obtain material of value. e. The shaft of a mine; a shaft mine; a trial pit. Nelson f. The underground portion of a colliery, including all workings. Used in many combinations, as pit car, pit clothes, etc. g. In hydraulic mining, the excavation in which piping is carried forward. h. Commonly, a coal mine, but not usually called so by workers, except in reference to surface mining where the workings may be known as a strip pit. BCI i. See: abyss 2349

pit ash Ash in coal derived from the dirt bands, adjoining shales or cleat minerals. Tomkeieff pit bank a. Eng. The raised ground or platforms upon which the coal is sorted and screened at the surface. See also: heapstead; pit brow; pithead; pit hill. b. Scot. The surface of the ground at the mouth of a pit, or shaft. pit bar One of the wooden props bracing the sides of a pit. Standard, 2 pit boss A mine foreman who is in direct charge of workers in a specific portion of a pit or mine. Also called shift boss. See also: pit foreman DOT pit bottom The bottom of a shaft and all the equipment and roadways around it. See also: loop-type pit bottom pit brow The pithead, and in particular, the mouth of the shaft. The edge or brow of a pit. See also: brow pit cage The structure used in mine shafts for transport purposes. See also: cage pit-car loader A short, electrically powered, lightweight elevating conveyor designed for use in working places, to facilitate the loading of large cars or to aid in shoveling long distances. The loader shovels into the hopper end and the conveyor carries the coal to the car. Jones, 1 pit-car-loader operator In bituminous coal mining, a person who operates a machine to load coal in mine (pit) cars. DOT 2350

pit-car repairer See: mine-car repairman pitch a. The angle between the horizontal and any linear feature, such as an ore shoot or lineation, measured in the plane containing the linear feature. See also: rake b. The angle between the horizontal and an axial line passing through the highest or lowest points of a given stratum in an anticline or syncline. c. Loosely, the grade, rise, or incline of a seam or bed. d. A vein-form deposit that follows dipping joint planes. This usage is confined largely to the Upper Mississippi Valley lead-zinc deposits. e. The slope of a roof, in inches (or centimeters), of vertical rise per horizontal foot (or meter). f. The distance between tooth centers, as in a gear wheel, or the number of teeth per unit of diameter. See also: pitch line g. The grade of an incline or the rise of a coal seam. BCI h. The solid or semisolid residue from the partial evaporation of tar. Strictly, pitch is a bitumen with extraneous matter, such as free carbon, residual coke, etc. Nelson i. The angular inclination of an ore shoot with respect to the surface, measured in the direction of the strike. Nelson j. Of a lode, angle of deviation from the vertical taken by a section of ore having some special characteristic, such as enhanced value. Pryor, 3 k. The angle that a directional feature, for example, slickensides, in a plane makes with a horizontal line within the plane. BS, 11 l. In dredging, the distance between the center of any pin and that of the pin in the next adjacent bucket. Fay m. See: dip n. The slope of a surface or tooth relative to its direction of movement. Nichols, 1 o. In a roller or silent chain, the space between pins, measured center to center. Nichols, 1 p. The amount of advance of a single-thread screw in one turn, expressed in lineal distance along or parallel to the axis, or in turns per unit of length. Standard, 2 q. The distance between corresponding points on adjacent projections produced on work by a cutting tool. ASM, 1 pitch arm One of the rods, usually adjustable, which determine the digging angle of a blade or bucket. Nichols, 2 pitchblende The massive variety of uraninite, UO(2+x) ; radioactive; black to dark brown; the most important ore of uranium; occurs widely in hydrothermal veins and the disseminated uranium-vanadium deposits of the Colorado Plateau type. Syn: pitch ore pitch circle The circle passing through the chain joint centers when the chain is wrapped on the sprocket. Jackson, 1 2351

pitch diameter The diameter of a circle that passes through the points of average contact between the teeth of two gears running in mesh, or between the teeth of a sprocket and the roller of its companion chain, or between a male and a female thread that are engaged. Brantly, 2 pitcher One who picks over dumps for pieces of ore. Webster 3rd pitches and flats See: flats and pitches pitching bar A kind of pick used, esp. by miners, in beginning a hole. Webster 2nd pitching chisel A chisel used for making an edge on the face of a stone. Also called pitching tool. Webster 3rd pitching seam A highly inclined seam. In coal mining, called edge coal. Nelson pitch length The length of an ore shoot in its greatest dimension. pitch line a. The line on which the pitch of gear teeth is measured; an ideal line, in a toothed gear or rack, bearing such a relation to a corresponding line in another gear with which the former works that the two lines will have a common velocity, as in rolling contact. See also: pitch Webster 3rd b. The line along which the pitch of a rack is marked out, corresponding to the pitch circle of a spur wheel. CTD pitch off A quarry worker's term for trimming an edge of a block of stone with a hammer and set. Fay pitch ore 2352

See: pitchblende; pitchy copper ore. pitchstone A dark, resinous volcanic glass. pitchwork In coal mining, work done on shares. Standard, 2 pitch working Mine working in a steeply inclined seam. pitchy adj. Resembling the appearance or properties of pitch. pitchy copper ore a. A dark, pitchlike oxide of copper. Syn: pitch ore b. A mixture of chrysocolla and limonite. pitchy iron ore a. An old syn. for pitticite. See: pitticite b. See: triplite pit efficiency In order to allow for the friction of the skips on the guides and between the air and the skips in the shaft and for other small losses, it is usual to divide the total static torque at any point of the wind by 0.9 for a new shaft with rope guides, or 0.85 for an old shaft with rigid guides. This factor is generally referred to as pit efficiency. Sinclair, 5 pit eye Bottom of a pit shaft from which the sky is visible. Pryor, 3 pit-eye pillar A barrier of coal left around a shaft to protect it from caving. Fay pit foreman

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In bituminous coal mining, a foreman who is in immediate charge of all mining operations in a strip mine. See also: pit boss pit frame a. The framework carrying the pit pulley. See also: headframe Fay b. The framework in a coal mine shaft. Standard, 2 pit guide An iron column that guides the cage in a mine shaft. Standard, 2 pit hand In the iron and steel industry, a general term applied to workers who perform varied duties around the processing furnaces. DOT pithead a. Landing stage at the top of a shaft. Pryor, 3 b. The top of a mine shaft including the buildings, roads, tracks, plant, and machines around it. See also: pit brow pithead output The total tonnage of raw coal produced at a colliery, as distinct from saleable output. It is the tonnage of coal as weighed before it enters the coal-preparation plant. See also: runof-mine pit hill Eng. See: pit bank pit lamp An open lamp worn on a miner's cap, as distinguished from a safety lamp. pit limit Either the vertical or lateral extent to which the mining of a mineral deposit by open pitting may be economically carried. The cost of removing overburden or waste material versus the minable value of the ore so exposed is usually the factor controlling the limits of a pit. pitman 2354

a. The worker who regularly examines the condition of mine infrastructure. Nelson b. A connecting rod, such as in the Blake type of jaw crusher; the vertical member linking the eccentric shaft with the toggles between the frame and the lower end of the movable jaw. pitman arm An arm having a limited movement around a pivot. Nichols, 1 pitmen Workers employed in shaft sinking or shaft inspection and repair. CTD pit mining Surface mining in which the material mined is removed from below the surrounding land surface. AIME, 2 pitotmeter An instrument that consists essentially of two pitot tubes one of which is turned upstream and the other downstream and that is used to record autographically the velocity of a flowing liquid or gas. Webster 3rd Pitot-static tube When the Pitot tube and static tube are combined, they form the Pitot-static tube, and as such they can be used as an anemometer. The tubes are usually arranged concentrically. When they are connected to the opposite sides of a manometer, the dynamic or velocity pressure will be measured directly. Roberts, 1 Pitot tube Consists of two concentric tubes bent in an L shape. In operation, the instrument is pointed in the direction of air flow: the inner tube, open at the end directed upstream, measures total head, and the outer tube, perforated with small openings transverse to the air flow, records static head. Each tube is connected to a leg of a manometer, when reading velocity head. Hartman, 1 pit pony A pony used for packing or haulage in a mine. Webster 3rd pit prop

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a. A piece of timber used as a temporary support for a mine roof. Zern b. Length of timber used as a roof support in longwall mining. Modern variants include expandable steel props which can be hydraulically or mechanically lengthened; used in stratified deposits. Pryor, 3 pit quarry An openpit quarry sunk below ground level. Access is gained by stairs, ladders, or mechanical hoists, and material is conveyed from the quarry by inclined tracks, trucks, derricks, or cableway hoists. These pits may reach depths of several hundred feet. A drainage scheme will in most cases be necessary, as the pit will form a natural sump for both surface and subsoil water. This type of quarry is often used for gravel or soft rock that can be extracted by some form of digging. See also: hillside quarry pit room a. The number of working places, or the length of a longwall face, available in a mine for coal production. Nelson b. The extent of the opening in a mine; pit space. Fay pit rope Eng. Winding rope; a hoisting rope. Fay pit sampling a. Use of small untimbered pits to gain access to shallow alluvial deposits or ore dumps for purpose of testing or valuation. Pryor, 3 b. Sampling shallow deposits by means of trial pits, usually about 2 to 3 ft (0.6 to 0.9 m) in diameter. In reasonably dry ground, depths of 50 ft (15.2 m) or more may be reached. Pit sampling is often used to assist site investigations as it provides the maximum of information regarding the nature of deposits and bedrock. See also: trial pit pit sand a. Sand usually composed of grains that are relatively angular; it often contains clay and organic matter. When washed and screened it is a good sand for general purposes. Zern b. Sand from a pit, as distinct from river or sea sand. Arkell pit shale The name given to the shale from a drift opened in the side of the ravine at a level 62 ft (18.9 m) below that of the Pittsburgh coal seam. Rice, 2 pit slope 2356

The angle at which the wall of an open pit or cut stands as measured along an imaginary plane extended along the crests of the berms or from the slope crest to its toe. pittasphalt An old name give to viscid bitumen. Syn: maltha See also: mineral tar pitticite The mineral amorphous, hydrous, ferric arsenate sulfate. It is brown to yellow and red; earthy; occurs as crusts and botryoidal layers; a common oxidation product of arsenical ores. Also spelled pittizite. Syn: pitchy iron ore pitting a. The act of digging or sinking a pit. Fay b. Testing an alluvial deposit by the systematic sinking of small shafts, the material recovered being subsequently tested. The practice is confined to shallow depths; i.e., down to about 50 ft (15.2 m) in fairly dry soft ground. Nelson Pittsburgh bed The Pittsburgh coal which outcrops prominently in the vicinity of Pittsburgh and extends under a large area of western Pennsylvania, northern West Virginia, northwestern Maryland, and eastern Ohio. It belongs in the Carboniferous system, Pennsylvanian series, at the base of the Monongahela formation. Rice, 2 pit water Water from the underground workings of a mine. BS, 5 pit wood The various kinds of timber used at a mine, mainly as supports. Nelson pitwork Cornish pumps and other engineering appliances in and near a mine shaft. Pryor, 3 pivot A nonrotating axle or hinge pin. Nichols, 1 pivoted-bucket carrier 2357

The highest type of combined elevator and conveyor. It consists of two long-pitch roller chains joined by crossbars on which are hung the buckets in such a way that they can be completely turned over. Pit and Quarry pivoted-bucket conveyor A type of conveyor using pivoted buckets attached between two endless chains that operate in suitable guides or casing in horizontal, vertical, inclined or a combination of these paths over drive-corner and takeup terminals. The buckets remain in the carrying position until they are tipped or inverted to discharge. Syn: bucket elevator pivot shaft A tractor dead axle, or any fixed shaft that acts as a hinge pin. Nichols, 1 pivot tube A hollow hinge pin. Nichols, 1 place a. See: in situ b. The part of a mine in which a miner works by contract is known as his "place" or "working place." c. A point at which the cutting of coal is being carried on. placer A deposit of sand or gravel that contains particles of gold, ilmenite, gemstones, or other heavy minerals of value. The common types are stream gravels and beach sands. See also: alluvial deposit; beach placer. placer claim a. A mining claim located upon gravel or ground whose mineral contents are extracted by the use of water, by sluicing, hydraulicking, etc. The unit claim is 1,320 ft2 (122.6 m2 ) and contains 10 acres (4.1 ha). See also: mining claim b. Ground with defined boundaries that contains mineral in the earth, sand, or gravel; ground that includes valuable deposits not fixed in the rock. See also: claim; lode claim. c. The maximum size of a placer claim is 20 acres (8.1 ha). Association claims of two or more persons may be located up to an area of 160 acres (64.8 ha) for eight persons. Placer claims must have a discovery. They should be staked, a location notice posted, and recorded in the same manner as for lode claims, stating the mineral for which the location in made. Lewis placer digging

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a. The action of mining by placer methods. Craigie b. A place at which placer mining is or may be carried on. Craigie placer gold Gold occurring in more or less coarse grains or flakes and obtainable by washing the sand, gravel, etc., in which it is found. Also called alluvial gold. See also: stream gold placer ground Ground where placer mining can be done; i.e., where valuable minerals can be obtained by digging up the earth and washing it for the valued mineral. Craigie placer location A location of a tract of land for mineral-bearing or other valuable deposits upon or within it that are not found within lodes or veins in rock in place; a claim of a tract of land for the sake of the loose deposits on or near its surface. Ricketts placer mine a. A deposit of sand, gravel, or talus from which some valuable mineral is extracted. Hess b. See: placer mining placer mining a. The extraction of heavy mineral from a placer deposit by concentration in running water. It includes ground sluicing, panning, shoveling gravel into a sluice, scraping by power scraper and excavation by dragline, dredge or other mechanized equipment. Nelson b. Extracting the gold or other mineral from placers, wherever situated--in dry channels and in channels temporarily filled with water. The mineral may be found in deep channels, in navigable streams, or in estuaries or creeks and rivers where the sea ebbs and flows. Ricketts c. That form of mining in which the surficial detritus is washed for gold or other valuable minerals. When water under pressure is employed to break down the gravel, the term hydraulic mining is generally employed. There are deposits of detrital material containing gold which lie too deep to be profitably extracted by surface mining, and which must be worked by drifting beneath the overlying barren material. The term "drift mining" is applied to the operations necessary to extract such auriferous material. See also: dredge d. The extraction and concentration of heavy metals or minerals from placer deposits by various methods, generally using running water. CF: alluvial mining; hydraulic mining; drift mining. AGI placodine See: maucherite 2359

plaffeiite A fossil resin found in Switzerland. Tomkeieff plagihedral See: plagiohedral plagioclase a. Any of a group of feldspars containing a mixture of sodium and calcium feldspars, distinguished by their extinction angles; crystal; triclinic; Mohs hardness, 6; and sp gr, 2.6 to 2.7. Bennett b. A series of triclinic feldspars of general formula: (Na,Ca)Al(Si,Al)Si2 O6 ; at high temperatures it forms a complete crystal solution series from albite, NaAlSi3 O8 , to anorthite, An, CaAl2 Si2 O8 ; the series is arbitrarily subdivided and named according to increasing mole fraction of the An component: albite (An 0% to 10%), oligoclase (An 10% to 30%), andesine (An 30% to 50%), labradorite (An 50% to 70%), bytownite (An 70% to 90%), and anorthite (An 90% to 100%). The Al:Si ratio ranges with increasing An content from 1:3 to 1:1. Plagioclase feldspars are common rock-forming minerals, have characteristic polysynthetic twinning, and commonly display zoning. The term was originally applied to all feldspars having an oblique angle between the two main cleavages. CF: alkali feldspar; orthoclase. Syn: sodium-calcium feldspar plagioclase rhyolite A porphyritic extrusive rock with phenocrysts of plagioclase and quartz in a groundmass of orthoclase and quartz. Also called plagioliparite. Syn: dellenite plagioclastic Having the cleavage of plagioclase; breaking obliquely. Standard, 2 plagiohedral Having an oblique spiral arrangement of faces; specif., being a group of the isometric system characterized by 13 axes of symmetry but no center or planes. Also spelled plagihedral. Webster 3rd plagionite A monoclinic mineral, Pb5 Sb8 S17 ; metallic black to lead-gray; forms stubby tablets; an uncommon associate of other lead sulfosalts in hydrothermal veins. plain 2360

a. An extent of level, or nearly level, land; a region not noticeably diversified with mountains, hills, or valleys. Fay b. A flat, gently sloping or nearly level region of the sea floor. Hunt c. Archaic. Relatively free of gaseous inclusions. ASTM plain clinometer A clinometer having only its upper end threaded to fit drill rods. Also called end clinometer. See also: clinometer wedge clinometer. Long plain concrete Concrete with no reinforcement. Hammond plain detonator A detonator for use with a safety fuse. It consists of an aluminum tube closed at one end and partly filled with a sensitive initiating explosive. The tube is only partially filled because a plain detonator is always used in conjunction with a safety fuse, and the empty space enables the fuse to be inserted into the tube until it comes into contact with the detonating composition. The safety fuse is then secured in position by indenting the detonator tube, this process being known as crimping. The combination of safety fuse and plain detonator is called a capped fuse. BS, 12; McAdam, 2 plain pilot A pilot in the surface of which no cutting points, such as diamonds or slugs, are inset. See also: pilot plaiting A texture seen in some schists that results from the intersection of relict bedding planes with well developed cleavage planes. AGI plan a. A map showing features--such as mine workings, geological structures, and outside improvements--on a horizontal plane. See also: colliery plan b. A scheme or project for mine development. See also: planning Nelson c. The system on which a colliery is worked, such as longwall, room-and-pillar, etc. Zern planar Lying or arranged as a plane or in planes, usually implying more or less parallelism, as in bedding or cleavage. It is a two-dimensional arrangement, in contrast to the onedimensional linear arrangement. AGI 2361

planar cross-bedding a. Cross-bedding in which the lower bounding surfaces are planar surfaces of erosion. It results from beveling and subsequent deposition. AGI b. Cross-bedding characterized by planar foreset beds. AGI planar element A fabric element having two dimensions that are much greater than the third; e.g., bedding, cleavage, and schistosity. CF: linear element AGI planar flow structure See: platy flow structure planar gliding Uniform slippage along plane surfaces. AGI planar structure See: platy flow structure planation The widening of valleys through lateral corrasion by streams after they reach grade and begin to meander and form floodplains. Also, by the extension, the reduction of divides and the merging of valley plains to form a peneplain; peneplanation. plane a. Any roadway, generally inclined but not necessarily so, along which ore or workers are conveyed by mechanical means from one bed to another or to a lower elevation in the same bed. See also: bedding plane; fault plane; slope. Nelson b. A road on the natural floor of a seam. Mason c. A two-dimensional form that is without curvature; ideally, a perfectly flat or smooth surface. In geology the term is applied to such features as a bedding plane or a planation surface. Adj: planar. See also: surface AGI d. In crystallography, a plane of symmetry dividing a crystal structure into two mirror images. See also: symbols of crystal faces e. A level surface bounded by straight lines, such as the faces of crystals. Gordon plane course Scot. In the direction facing the joint planes. Syn: on plane 2362

plane engineer See: slope engineer plane fault A fault with a surface that is planar rather than curved. plane figure A plane surface bounded either by straight lines or curved lines or by a combination of straight and curved lines. Jones, 2 plane group The 17 possible combinations of symmetry elements which may coexist in 2 dimensions. CF: space group plane man See: incline man plane of saturation See: water table plane of stretching A low-angle gravity (normal) fault resulting from stretching of the solidified top of an igneous intrusion. plane of symmetry Any plane which divides a crystal, crystal structure, or crystal symmetry such that each side is a mirror reflection of the other. Represented as m or 2 and graphically as a solid or heavy line. Syn: mirror plane plane or rectangular coordinate Either of two perpendicular distances of a point from a pair of rectangular coordinate axes. Seelye, 2 plane-polarized light Light with its electric vector confined to a plane. 2363

planer a. First developed as a fixed-blade device for continuous longwall mining of narrow seams of friable coal, this machine is pulled along the coal face, planing a narrow cut. Vibrating-blade planers were designed later in an attempt to apply the technique to harder coal; they have also been experimented with in the phosphate mines in western Montana and northern Idaho. b. A machine provided with a cutting tool having lateral and vertical adjustment that is widely used in stone trimming. Both sides and tops of blocks may be planed to desired dimensions. Some planers may be adjusted to cut curved forms. planerite A triclinic mineral, Al6 (PO4 )2 (PO3 OH)2 (OH)8 .4H2 O ; turquoise group. plane schistosity A type of schistosity characterized by the arrangement of tabular and prismatic grains in parallel planes. plane shear One of four types of slope failure. Plane shear failure results when a natural plane of weakness, such as a fault, a shear zone, or bedding plane exists within a slope and has a direction such as to provide a preferential path for failure. Large intact portions of the slope rock may slide along this plane surface. Woodruff plane strain A state of strain in which all displacements that arise from deformation are parallel to one plane, and the longitudinal strain is zero in one principal direction. AGI plane stress A state of stress in which one of the principal stresses is zero. plane surveying Ordinary field and topographic surveying in which Earth curvature is disregarded and all measurements are made or reduced parallel to a plane representing the surface of the Earth. The accuracy and precision of results obtained by plane surveying may decrease as the area surveyed increases in size. CF: geodetic surveying plane table 2364

a. An instrument for plotting the lines of a survey directly from the observations; consisting essentially of a drawing board mounted on a tripod and fitted with a ruler that is pointed at the object observed, usually with the aid of a sighting device, such as a telescope. Webster 3rd b. An inclined ore-dressing table. Standard, 2 planetary geared drum A drum containing planetary gearing that is used to control the motion of the rope drums on certain types of mining machines. In planetary gearing, which is used when a large ratio of speed reduction with only a few operating gears is required, some or all of the gear wheels in the train of mechanism have a motion about an axis and a revolution about the same axis. Jones, 1 planetary lap A type of machine lap employing a number of geared workholders that rotate with an epicyclic motion between two stationary lapping plates. The crystals being lapped, when contained in pentagonal holes in the workholder, have an imposed rotatory motion. Also known as the Hunt-Hoffman lap or Bendix lap. Am. Mineral., 2 planetary mill Mill used for making very large reductions on slabs by one pass through the mill. The mill consists of two large plain rolls, each surrounded by many small work rolls. Osborne planetary set gear A gearset consisting of an inner (sun) gear, an outer ring with internal teeth, and two or more small (planet) gears meshed with both the sun and the ring. Nichols, 1 plane tender See: slope engineer planet gearing Gearing in which one gear wheel revolves around another. Mason planimeter An instrument for measuring the area of any plane figure by passing a tracer around its boundary line. Webster 3rd planimetric analysis 2365

Analysis of patterns in a fabric diagram based on distribution of points and areal comparisons. AGI planimetric map A map that presents only the relative horizontal positions of natural or cultural features, by lines and symbols. It is distinguished from a topographic map by the omission of relief in measurable form. Syn: line map planimetry a. The measurement of plane surfaces; e.g., the determination of horizontal distances, angles, and areas on a map. AGI b. The plan details of a map; the natural and cultural features of a region (excluding relief) as shown on a map. AGI planisher A device for flattening thin sections cut for microscopic examination. Standard, 2 plank timbering The lining of a shaft with rectangular plank frames. See also: box timbering plankton The whole community of rifting small plants and animals in layers of the water. This term is frequently used to describe all life forms, regardless of size, which have no means of significant self-locomotion. This community can be divided into the phytoplankton (plants) and the zooplankton (animals). Hy plankton bloom The rapid growth and multiplication of plankton, usually plant forms, producing an obvious change in the physical appearance of the sea surface, such as coloration or slicks. Also called sea bloom; florescence. Hy planktonic Relating to the chiefly simple types of floating and surface-dwelling forms of organisms of the ocean waters. Schieferdecker plank tubbing The lining of a shaft with planks, spiked on the inside of curbs. See also: tubbing 2366

planning The predesign of the detailed layout, main roadways, and workings of a mine or group of mines. The scheme usually involves the introduction of mechanical equipment for the working and transport of the coal or mineral. The selection of mining methods and machines properly adapted to the local conditions is part of planning. Nelson planning engineer A mining engineer responsible for mine planning. The engineer is attached to the planning department of a large mine or a group of smaller mines and is qualified by training, experience, and technical qualifications to envisage new development work and coordinate the ideas of other experts such as a mechanization engineer, ventilation engineer, mining geologist, etc. Nelson planometric projection Pictorial view of an object showing it in plan with oblique lines showing the front, side, and thickness. See also: projection planosol A great soil group in the 1938 classification system; an intrazonal, hydromorphic group of soils having a leached surface layer above a definite clay pan or hardpan. These soils develop on nearly flat upland surfaces under grass or trees in a humid to subhumid climate. AGI plant a. The shaft or slope, tunnels, engine houses, railways, machinery, workshops, etc., of a colliery or other mine. b. To place gold or any valuable ore in the ground, in a mine, or the like to give a false impression of the richness of the property. To salt, as to plant gold with a shotgun. See also: salting a mine c. In mining, the mechanical installations, machines, and their housings. Earthworks are sometimes loosely included. Pryor, 3 d. Used to include the machinery, derricks, railway, cars, etc., employed in tunnel work. Stauffer plant mix The process of soil stabilization in which the soil is carried to a stationary mixer, returned to the site after mixing and then spread. CF: mix-in-place plant-mixed concrete

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Concrete that is mixed at a central mixing plant and delivered to a site in special equipment designed to prevent its segregation. Hammond plant-mix method A method of preparing aggregates for bituminous surfaces in which aggregates and bitumen are combined in a plant situated at the road or at a relatively long distance from the road. Also known as the premixed method. Pit and Quarry plant scrap Scrap metal produced in the plant itself; e.g., sprues and gates in a foundry or defective ingots and hot tops in a steel mill. Also called home scrap. Newton, 1 plasma a. Gas comprising equal amounts of positively and negatively charged particles; a fourth state of matter (solid, liquid, gas, plasma) capable of conducting magnetic force. Pryor, 3 b. A bright-, leek-, to emerald-green subtranslucent variety of cryptocrystalline (chalcedonic) quartz. The green color is attributed to chlorite. CF: bloodstone; heliotrope. c. That part of a soil which can be or has been moved, reorganized, and/or concentrated by soil-forming processes. plasma jet a. A jet formed by passing a high-speed current of nitrogen or a mixture of nitrogen and hydrogen over a tungsten electrode placed in a specially designed narrow orifice in a cutting torch. An arc is struck between this electrode and the earthed nozzle of the torch, which is cooled by a water jacket. When a plasma jet is used to cut rock, two separate zones of action can be expected. Min. Miner. Eng., 1 b. Ionized gas produced by passing an inert gas through a high-intensity arc, causing temperatures up to tens of thousands degrees centigrade. Harbison-Walker plastering See: mudcapping plaster mill A machine consisting of a roller or set of rollers for grinding lime or gypsum to powder. Fay plaster pit Derb. A gypsum mine. 2368

plaster shooting a. A surface blasting method used when no rock drill is available or is not necessary. It consists of placing a charge of gelignite, primed with safety fuse and detonator, in close contact with the rock or boulder and covering it completely with stiff damp clay. The charges vary from 8 to 16 oz/yd3 (297 to 593 g/m3 ) of rock. See also: popping; snakeholing. Nelson b. A form of secondary blasting in which the explosive is detonated in contact with the rock without the use of a shothole. See also: secondary blasting; mudcapping. BS, 12 plaster stone See: gypsum plastic Said of a body in which strain produces continuous, permanent deformation without rupture. CF: elastic plastic and semiplastic explosive Any of several explosives used for commercial purposes. The consistency is such that the explosive can be shaped by moderate pressure to fill a drill hole. The difference between plastic and semiplastic form is primarily dependent on the difference in equipment which has been found necessary in manufacturing cartridges of the explosive. The viscosity of the plastic type makes it possible to produce cartridges by a process of extrusion through tubes. Fraenkel plastic clay Any clay, but chiefly kaolinite, which, when mixed with water, is easily shaped and retains this shape until fired. plastic deformation a. Permanent deformation of the shape or volume of a substance, without rupture. It is mainly accompanied by crystal gliding and/or recrystallization. Syn: plastic flow; thixotropy. CF: plastic strain AGI b. Deformation by one or both of two grain-scale mechanisms: slip, and twinning. This is a metallurgical definition, increasingly used by geologists. Sometimes called crystal plasticity. AGI c. Rheological term for deformation characterized by a yield stress, which must be exceeded before flow begins. AGI d. An elastic deformation of brittle minerals--such as olivine under mantle conditions, or quartz, during metamorphism; deformation occurs along well-defined crystallographic planes in specific directions, which may be preserved as thin deformation lamellae or as deformation twinning. It may be annealed out by recrystallization. CF: elastic 2369

deformation e. Irreversible deformation of metallic minerals, such as gold or copper. See also: malleability plastic design The design of steel or reinforced-concrete structural frames which is based on the assumption that plastic hinges form at points of maximum bending moment. See also: elastic design; plastic modulus. Hammond plastic explosive See: plastic and semiplastic explosive plastic firebrick A common term for both high duty and super-duty fire clay plastic refractories. plastic flow See: plastic deformation plastic fracture The breakage of a solid material under load when being permanently deformed. Hammond plastic igniter cord A corklike device for lighting a safety fuse. When the cord is ignited an intense flame passes along its length at a uniform rate and ignites the blackpowder core of an ordinary safety fuse. Two types are made: the fast has a nominal burning speed of 1 s/ft (3.3 s/m); the other is about 10 times as slow. Nelson plasticity The property of a material that enables it to undergo permanent deformation without appreciable volume change, elastic rebound, or rupture. See also: plastic deformation; plastic flow; plastic limit; plastic soil; plastic state; plasticity index. ASCE plasticity index The water-content range of a material at which it is plastic, defined numerically as the liquid limit minus the plastic limit. CF: Atterberg limits; plastic limit. plasticizer 2370

A material, usually organic, capable of imparting plastic properties to nonplastics or improving the plasticity of ceramic mixtures. Syn: wetting agent plastic limit a. The water-content boundary beyond which a soil can be rolled into a thread approx. 3 mm in diameter without crumbling, i.e., beyond which it is plastic. b. The water content of a soil or clay material corresponding to an arbitrarily defined boundary between a plastic and a semisolid state. CF: Atterberg limits; plasticity index. plastic modulus A factor used in the plastic design of steel structures. It is a constant for each particular shape of section. See also: plastic design Hammond plastic soil a. A soil that can be rolled into 1/8-in (1.6-mm) diameter strings without crumbling. Nichols, 1 b. A soft, rubbery soil. Nichols, 1 c. A soil that exhibits plasticity. ASCE plastic solid A solid that undergoes change of shape continuously and indefinitely after the stress applied to it passes its elastic limit. plastic state The range of consistency within which a soil exhibits plastic properties. Also called plastic range. ASCE plastic strain In rocks, which are composed of many crystals commonly belonging to several mineral species, the term applies to any permanent deformation throughout which the rock maintains essential cohesion and strength regardless of the extent to which local microfracturing and displacement of individual grains may have entered into the process. CF: plastic deformation plastic tamping rod A tamping rod or stemmer, of a rigid nature, made from plastic possessing suitable dielectric properties. A plastic conducive to the building up of heavy charges of static electricity is unsuitable. Nelson plastic tooling 2371

Dies, jigs, and fixtures for metal forming, boring, assembly, and checking; made at a saving of time and labor, of laminated and cast components, and cemented into highly stable industrial tools, chiefly with epoxy and some with polyester resins. Epoxies are strong adhesive resins, particularly useful because of their low shrinkage factor. Polyesters have a cost advantage and are easy to handle. Crispin plastic yield The term commonly applied to plastic deformation. Hammond plastic zone In explosion-formed-crater nomenclature, this zone differs from the rupture zone by having less fracturing and only small permanent deformations. There is no distinct boundary between the rupture and plastic zones. Min. Miner. Eng., 2 Plast-Sponge High-quality iron powder made by reduction of iron oxide; used in powder metallurgy. Bennett plat a. The map of a survey in horizontal projection, such as of a mine, townsite, etc. b. A diagram drawn to scale showing land boundaries and subdivisions, together with all data essential to the description of the several units. A plat differs from a map in that it does not show additional cultural, drainage, and relief features. Seelye, 2 c. A platform, floor, or surface in or about a mine used esp. for loading and unloading ore, etc. Webster 3rd plate a. A flat iron or steel sheet laid around a mine-shaft collar, at the shaft bottom, or at any level station, to enable mine cars and other equipment to be easily turned and moved about. Also, a cast-iron plate with a circular ridge on which mine rail cars are turned at the junction of roads. b. A horizontal timber laid on a floor or sloping wall to receive a framework of timbers. c. A torsionally rigid thin segment of the Earth's lithosphere, which may be assumed to move horizontally and adjoins other lithosopheric plates along zones of seismic activity. See also: plate tectonics plate amalgamation Use of copper or copper-alloy plates coated with enough mercury to form a soft adherent film, in order to trap gold from crushed ore pulp as it flows over the plates. The resulting amalgam, containing up to 40% metallic gold, is periodically scraped off and more mercury is added to the film. Pryor, 3 2372

plate-and-frame filter A filter press consisting of plates with a gridiron surface alternating with hollow frames, all of which are held by means of lugs, on the press framework. The corners of both frames and plates are cored to make continuous passages for pulp and solution; the filter cloth is placed over the plates. The pulp passageway connects with the large, square opening in the frame; the solution and passageways connect with the gridiron surface of the plate. The Dehne and the Merrill are well-known types. Liddell plate apron feeder An automatic arrangement by which coal or ore is fed forward on steel plates forming segments linked together in an endless chain. See also: plate feeder plateau Broadly, any comparatively flat area of great extent and elevation; specif. an extensive land region considerably elevated (more than 150 to 300 m in altitude) above the adjacent country or above sea level; it is commonly limited on at least one side by an abrupt descent, has a flat or nearly smooth surface but is often dissected by deep valleys and surmounted by high hills or mountains, and has a large part of its total surface at or near the summit level. A plateau is usually higher and has more noticeable relief than a plain (it often represents an elevated plain), and it is usually higher and more extensive than a mesa; it may be tectonic, residual, or volcanic in origin. See also: tableland CF: mesa plateau basalt A term applied to those basaltic lavas that occur as vast composite accumulations of horizontal or subhorizontal flows, which, erupted in rapid succession over great areas, have at times flooded sectors of the Earth's surface on a regional scale. They are generally believed to be the product of fissure eruptions. CF: shield basalt AGI plateau gravel A sheet, spread, or patch of surficial gravel, often compacted, occupying a flat area on a hilltop, plateau, or other high region at a height above that normally occupied by a stream-terrace gravel. It may represent a formerly extensive deposit that has been raised by earth movements and largely removed by erosion. AGI plate bearing test A method by which the load bearing capacity of a soil may be estimated. See also: ultimate bearing pressure 2373

plate cleaner A device for cleaning raw coal which uses the difference in the coefficient of resilience or friction between clean coal and an inclined plate, commonly of steel, and that between refuse and the plate to allow the clean coal to jump over a gap while the refuse falls through. BS, 5 plate conveyor A conveyor in which the carrying medium is a series of steel plates, each in the form of a short trough, joined together with a slight overlap to form an articulated band. The plates are attached either to one center chain or to two side chains. The chains connect rollers running on an angle-iron framework and transmit the drive from the driveheads that can be installed at intermediate points as well as at the head or tail ends. A plate conveyor can negotiate bends down to about 20 ft (6.1 m) radius; available in widths 400, 540, and 640 mm with running speeds from 3 to 4 ft/s (0.9 to 1.2 m/s) with a carrying capacity from 100 to 400 st/h (90.7 to 362.8 t/h). Syn: steel plate conveyor plate coordinate In photographic mapping, either of two rectangular coordinates measured on a photograph with reference to the principal point as origin. Seelye, 2 plated crystal A crystal with a conductive surface film of gold, silver, aluminum, or other metal produced by cathode sputtering, evaporation, or chemical methods. The films, to which lead wires may be soldered, take the place of the conventional clamped metal electrodes. Am. Mineral., 2 plate feeder The mechanical plate feeder is a device for feeding material at a fixed and uniform rate. It is generally applied at the tail end of a conveyor or elevator which feeds a plant, but may be applied to feeding any other single unit. It relieves the pressure and drag, with the consequent unnecessary wear on the belt, which is ordinarily experienced if feeding from a hopper directly to a belt. It not only cuts maintenance costs by eliminating uneven wear, but increased output can be obtained by steady feeding. This type of feeder also handles wet aggregate. See also: disk feeder; reciprocating feeder. Pit and Quarry; ACSG, 2 plate former

2374

Used for lining shafts, winzes, and rises; usually constructed of comparatively thin steel sheeting, stiffened around the edges with angles. Plates should be of such size that they can be conveniently handled in the skips or buckets used for sinking. Spalding plate girder A built-up riveted or welded steel girder, having a deep vertical web plate, with a pair of angles riveted along each edge to act as compression and tension flanges. For heavier loads, flange plates are riveted or welded to the angles. Hammond plate roll A smooth roll for making sheet iron or plate iron, as distinguished from iron having grooves for rolling rails, beams, etc. Standard, 2 plate tectonics A theory of global tectonics in which the lithosphere is divided into a number of plates whose pattern of horizontal movement is that of torsionally rigid bodies that interact with one another at their boundaries, causing seismic and tectonic activity along these boundaries. AGI plate tongs Tongs for grasping and handling iron or steel plates. Standard, 2 platform a. The place on top of a breaker where the freshly mined coal is weighed by a weigh boss just before it is dumped into the machinery. Korson b. A wooden floor on the side of a gangway at the bottom of an inclined seam, to which the coal runs by gravity, and from which it is shoveled into mine cars. c. A plank or mesh steel-covered level area at the base of a drill tripod or derrick, used as a working space in front of a drill machine around the collar of the borehole. Sometimes the platform is large enough to act as a foundation and anchor for the drill machine. Long d. A scaffold. Fay e. A wood mat used in sets to support machinery on soft ground. Also called pontoon. Nichols, 1 f. An operator's station on a large machine, particularly on rollers. Nichols, 1 g. In the breaker, a flat or slightly inclined floor covered with iron plates onto which coal is run from the main screen bars and cleaned by platform workers. Korson h. Also a similar floored area in the tripod or derrick on which a laborer stands while working in a tripod or derrick. See also: floor Long platform gantry A gantry constructed for carrying a portal crane or a similar structure. Hammond 2375

platform hoist A power-driven hoist, having a lifting capacity ranging from 200 lb (90.7 kg) to about 21/2 st (2.27 t), which can be raised on a loading platform up to 200 ft (61 m) high. Hammond platina a. Twisted silver wire. Standard, 2 b. Crude native platinum. AGI platinic gold Said to be a native alloy containing 84.6% gold, 2.9% silver, 0.2% iron, 0.9% copper, and the remainder 11.4% platinum. Hess platiniridium An isometric mineral, (Ir,Pt) , with Ir 50% to 80% (atomic) of Ir + Pt; forms silver-white grains having sp gr, 22.6 to 22.8; Mohs hardness, 6 to 7. platinize To coat or combine with platinum, esp. by electroplating. Standard, 2 platinum a. An isometric mineral, native platinum 4[Pt] with variable Pd, Ir, Fe, Ni; malleable; ductile; metallic; sp gr, 21.45; corrosion resistant; occurs in ultramafic rocks, quartz veins, and in placers. b. A malleable and ductile silvery-white metal, when pure. Symbol: Pt. Occurs native, accompanied by small quantities of iridium, osmium, palladium, ruthenium, and rhodium. Used in jewelry, wire, vessels for laboratory use, and in many valuable instruments including thermocouple elements. Handbook of Chemistry and Physics, 3 platinum-group metal (PGM). Any of the minerals native platinum, osmium, iridium, palladium, rhodium, ruthenium, and their alloys, such as osmiridium (Ir,Os) , ruthenosmiridium (Ir,Os,Ru) , rutheniridosmine (Os,Ir,Ru) , and platiniridium (Ir,Pt) . Other alloys of PGM are exemplified by stanopalliadinite, (Pd,Cu)3 Sn2 (?) ; and potarite, PdHg . Other sources of PGM are sperrylite, PtAs2 ; cooperite, (Pt,Pd,Ni)S; stibiopalladinite, Pd5 Sb2 ; braggite, (Pt,Pd,Ni)S ; vysotskite, (Pd,Ni)S ; ruthenarsenite, (Ru,Ni)As ; cuproiridsite; CuIr2 S4 ; cuprorhodsit, CuRh2 S4 ; malanite, Cu(Pt,Ir)2 S4 ; and dayingite, CuCoPtS4 . Varietal terms include plyxene and ferroplatinum for iron alloys and cuproplatinum for copper alloys. 2376

platinum sponge Metallic platinum in a gray, porous, spongy form; obtained by reducing ammonium chloroplatinate, which occludes large volumes of oxygen, hydrogen, and other gases. Webster 3rd platting Brick laid flatwise on top of a kiln to keep in the heat. Fay plattman In bituminous coal mining, a colloquialism of English origin for a pusher who pushes loaded mine cars onto a cage from a platt (an enlarged underground opening at the shaft where cars are gathered prior to hoisting). DOT plattnerite a. A tetragonal mineral, PbO2 ; rutile group; dimorphous with scrutinyite; iron black; occurs in lead mines. b. Erroneous spelling of planerite. platy flow structure An igneous rock structure of tabular sheets suggesting stratification. It is formed by contraction during cooling; the structure is parallel to the surface of cooling and is commonly accentuated by weathering. Syn: platy structure; planar flow structure. AGI platynite A trigonal mineral, PbBi2 (Se,S)3 ; metallic; iron-black; forms thin plates like graphite; at Falun, Sweden. Also spelled platinite. platy structure See: platy flow structure playa a. A term used in southwestern United States for a dry, vegetation-free, flat area at the lowest part of an undrained desert basin, underlain by stratified clay, silt, or sand, and commonly by soluble salts. The term is also applied to the basin containing an expanse of playa, which may be marked by ephemeral lakes. See also: salina; alkali flat; salt flat; salar. Syn: dry lake b. See: playa lake c. A small, generally sandy land area at the mouth of a stream or along the shore of a bay. Etymol: Spanish, beach, shore, coast. AGI 2377

playa basin See: bolson playa lake A shallow, intermittent lake in an arid or semiarid region, covering or occupying a playa in the wet season but drying up in summer; an ephemeral lake that upon evaporation leaves or forms a playa. Syn: playa AGI play of color A pseudochromatic optical effect resulting in flashes of colored light from certain minerals, such as fire opal and labradorite, as they are turned in white light. Periodic spacings of phases with slightly differing refractive indices act as optical diffraction gratings in these minerals. CF: fire; opalescence; pseudochromatism. Syn: schiller plenargyrite See: matildite plenum a. A system of ventilation in which air is forced into an inclosed space, such as a room or a caisson, so that the outward pressure of air in the space is slightly greater than the inward pressure from the outside, and thus leakage is outward instead of inward. b. A mode of ventilating a mine or a heading by forcing fresh air into it. c. Use of compressed air to hold soil from slumping into an excavation. Nichols, 1 pleochroic See: pleochroism pleochroic halo a. A minute zone of color or darkening surrounding and produced by a radioactive mineral crystal or inclusion. AGI b. Any of the concentrically colored aureoles in minerals--e.g., micas, fluorite, and cordierite--centered by minute grains of minerals containing radioactive elements, such as zircon and monazite. This discoloration results from crystal structural radiation damage from alpha decay. pleochroism a. The property of exhibiting different colors in different directions by transmitted polarized light. AGI b. More precisely, the property of absorbing differently, light that 2378

vibrates in different directions in passing through a crystal. If the crystal is uniaxial the change of color is called dichroism; if the crystal is biaxial, the change of color is called pleochroism. AGI c. The property of birefringent crystals (minerals) to absorb various wavelengths of light differentially depending on the vibration direction of the light within the crystal. Thus a mineral displaying pleochroism shows various colors or tints when it is traversed by plane polarized light and the orientation of the crystal is varied with respect to the plane of polarization. It is a common and diagnostic property of many minerals, and is easily observed under the petrographic microscope or a dichroscope. AGI d. The capacity of strongly anisotropic minerals to change absorption colors with changing electric vector in plane-polarized light; e.g., as seen with a polarized-light microscope. Uniaxial minerals may be dichroic and biaxial ones trichroic. Qualitative pleochroism is change of intensity in the same color; quantitative pleochroism shows change of color with change of orientation. Adj: pleochroic. CF: dichroism; trichroism. Syn: polychroism pleomorphism See: polymorphism pleonaste See: ceylonite plessite A fine grained intergrowth of kamacite and taenite. pliable armored cable A flexible cable having collective armor comprising stranded groups of fine, galvanized, steel wires. BS, 13 pliable support A support composed of elastic materials that either yields to the roof pressure, or permits the subsidence of the roof without the support being completely destroyed and losing its significance. Stoces plication Intense, small-scale folding. Adj: plicated. CF: crenulation AGI ploat Eng. To dress down or remove loose stone from the roof or sides. SMRB 2379

plombierite A mineral, Ca5 H2 Si6 O18 .6H2 O(?) . plot mark A mark made in a bit mold, bit die, or blank bit where a pip or hole is drilled to receive or to encompass a diamond. Long plotting instrument A large drawing machine by means of which stereoscopic pairs of vertical photographs can be viewed in conjunction with their ground control points and mechanically translated into accurate maps. Hammond plotting scale A scale used for setting off the lengths of lines in surveying. plow a. In coal mining, a cutter loader with knives or blades, which is pulled along the longwall face by a powerful chain. The broken coal is loaded onto an armored flexible conveyor which, with the aid of hydraulic rams, holds the plow up to the coal face and causes the knives to bite into the coal as they are pulled along. The plow is a continuous mining machine. See also: plow-type machine b. Applied to V-shaped belt scrapers that are attached to the belt conveyor frame and which press against the return belt. They are intended to remove coal or other material that might stick to the return belt and be crushed as the belt passes over the driving rolls or the return pulley. Jones, 1 plow cut See: V-cut plow deflector a. A steel plate attached to the end of a cutter loader for deflecting cut coal onto the face conveyor. Nelson b. A device for removing or diverting the dust and dirt off a belt conveyor and thus prevent it being carried back along the return belt. Nelson plow steel A high-tensile steel used in the manufacture of hoisting ropes. plow-type machine 2380

Plows may be divided into two classes: (1) machines that peel the coal to a depth of from 1 to 12 in (2.54 to 30.5 cm) by knives of various designs and the cut coal is then loaded onto a heavy type scraper chain conveyor; and (2) machines that peel a thin slice up to 2 in (5.1 cm) in thickness, by knives attached to each end of a steel box, and the coal is dragged along the face inside the box. From the aspect of speed of travel, plows may be divided into: (1) slow-moving types of 10 to 20 ft/min (3.0 to 6.1 m/min), which remove a thicker slice; and (2) fast-moving types at about 80 ft/min (24.4 m/min), which take a relatively thin slice. See also: Anbauhobel; continuous mining; Lobbe Hobel. Nelson plucking a. Describes the sudden jerking or plucking on heavy endless-rope haulage when the rope again takes the load, following rope coils. Instead of slipping smoothly sideways, the rope tends to stick until the pressure of oncoming coils overcomes the friction; these slip suddenly, producing a momentary slackening followed by a sudden jerk or pluck as the rope again takes the load. This may loosen chains or clips and cause derailments and runaway sets. Sinclair, 5 b. The disruption of blocks of rock by a glacier or stream. Standard, 2 plug a. A watertight seal in a shaft formed by removing the lining and inserting a concrete dam, or by placing a plug of clay over ordinary debris used to fill the shaft up to the location of the plug. BS, 10 b. See: hoisting plug c. A steel cylinder placed inside the annular opening in a coring bit to convert it for use as a noncoring bit. The face of the plug may or may not be provided with serrations, inset diamonds, or other types of cutting edges. Long d. See: block e. See: cartridge f. A cylindrical piece of wood or an expandable metal apparatus placed in a borehole to act as a base into which the drive wedge of a borehole deflection device is driven. g. Small wooden pin driven into a hole in the rock roof of a tunnel. The axis of the tunnel is marked on such plugs by tacks, or by small iron hooks from which a plummet lamp may be suspended for sighting upon. Stauffer h. To plug a well by cementing a block inside casing or capping the well with a metal plate. Wheeler, R.R. i. Any block installed within casing to prevent movement of fluids. Wheeler, R.R. j. A steel wedge used in quarrying dimension stone. See: plugand-feather method k. A vertical, pipelike body of magma that represents the conduit to a former volcanic vent. CF: neck plug-and-feather hole A hole drilled for the purpose of splitting a block of stone. These holes are usually in rows. The plug is a slightly wedge-shaped piece of iron driven between two L-shaped irons, or feathers, inserted in the hole. Stauffer plug-and-feather method 2381

A method used in quarrying to reduce large masses of stone to smaller size. By using a hammer drill, a row of shallow holes is made along the line where a break is desired. The feathers consist of two iron strips flat on one side for contact with the wedge, and curved on the other to fit the wall of the drill hole. They are placed in the hole and the plug (a steel wedge) is placed between them. They are sledged lightly in succession until a fracture appears. Wherever possible, such fractures are made parallel with the rift of the stone. Syn: multiple wedge See also: plug plug bit a. A diamond bit that grinds out the full width of a hole. Nichols, 1 b. A noncoring diamond-set bit that can be in the form of a bullnose bit, pilot bit, or concave bit. Also called bullnose bit; concave bit; noncore bit; pilot bit. BS, 9 plug box Eng. A wooden water pipe used in coffering. plug drill A stonecutter's percussion drill. Webster 3rd plugged a. A borehole that has been filled or capped with a long plug, or in which a plug has been inserted. Long b. Cracks or openings in the rocks in the walls of a borehole that have been filled or sealed with cement or other substances. Long c. A borehole that has been drilled with a plug or noncoring bit. Long d. A blocked core barrel or bit. Long e. A coring bit in which a plug has been inserted. See also: plug Long plugged bit a. See: noncoring bit b. A core bit, the annular opening of which is tightly closed or blocked by a piece or the impacted fragments of a core. Long plugged crib A curb supporting the walling in a shaft and is itself supported on plugs or bolts driven into the ground around the shaft. The crib may be removed when the walling from below is carried up to it. See also: strata bolt Nelson plugging a. The stopping of the flow of water into a shaft by plugs of clay. Zern b. The material used, the act, or the process of inserting a plug in a borehole to fill it or the cracks and 2382

openings in the borehole sidewalls. Long c. The act or process of drilling a borehole with a noncoring bit. Long d. The practice of filling holes and cavities in castings with porous silicate mixture (cast iron filler) before the application of cover coats. The filler must be firmly forced into the casting holes, since any entrapped air beneath the filler will expand during firing and force the material out causing blowholes. Enam. Dict. plughole a. A passageway that is left open, while working on an explosion-proof stopping, for the purpose of maintaining the ventilation of the fire area at or as near the normal quantity as possible, to prevent any increase in the combustible gases content in the air. After the stopping is completed, this hole is plugged up with sandbags in order to completely seal off the mine area. The plughole is generally a tapered passageway of about 3.5 ft (1.1 m) square at the inby side of the stopping and 2.5 ft (0.76 m) square at the outby side. McAdam, 1 b. See: block hole plughole stopping A stopping in which the floor and the sidewalls of the passage are built of sandbags, and the roof may be the roof of the roadway or covering boards used between the webs of steel arches, or preferably, corrugated steel sheeting used as lagging behind steel arches. The plughole or passage is generally tapered from the inby end from 3 to 3.5 ft (0.9 to 1.1 m) square to 2.5 ft (0.76 m) square so that, in the event of an explosion, the plug of sandbags in the passage is subjected to a wedging action assisting to retain the plug in place. The plughole may be placed in the most convenient position and although this is often at the top, it is sometimes placed to the side and reasonably near the floor. Sinclair, 1 plugman See: pumping engineer plug shot Scot. A small charge exploded in a hole to break up a stone of moderate size. plug valve A valve or cock opened or closed by the turning of a plug, usually conical in shape. Not to be confused with needle valve or globe valve. Long plum a. A large random-shaped stone dropped into a large-scale mass of concrete to economize on the volume of the concrete. Hammond b. An old form of plumb. Fay 2383

plumb a. See: vertical b. See: plumb bob; plumbline. c. To carry a survey into a mine through a shaft by means of heavily weighted fine wires hung vertically in the shaft. The line of sight passing through the wires at the surface is thus transferred to the mine workings. An important piece of work: in mine shafts, and in transferring courses or bearings from one level to another. Fay plumbago a. A special quality of powdered graphite used to coat molds, and in a mixture with clay, to make crucibles. b. See also: black lead; graphite. c. Impure graphite or graphitic rock. d. Minerals resembling graphite; e.g., molybdenite. plumbago crucible Highly refractory crucible composed of a mixture of about equal parts of refractory clay and graphite. Osborne plumb bob a. A small weight or bob, hanging at the end of a cord, which under the action of gravity is oriented in a vertical direction. Also called a plummet. CTD b. A pointed weight hung from a string. Used for vertical alignment. Nichols, 1 plumber's dope A soft sealing compound for pipe threads. Nichols, 1 plumbic Of, pertaining to, or containing lead, esp. in its higher valence. CF: plumbous plumbiferous Containing lead. Webster 3rd plumbing Transferring a point at one level to a point vertically below or above it by means of a weight (plumb bob or plummet) suspended at the end of a string or wire (plumbline). See also: centering of shaft; string survey. Nelson plumbline 2384

A device used to produce a vertical line between a survey instrument and the reference point over (or sometimes under, in underground work) which it is set. Special plumblines are used in a vertical shaft to transfer a fixed or an azimuth angle from the surface to underground workings for the purpose of orientation. Also known as plumb bob; plummet. See also: Weisbach triangle plumbocalcite A variety of calcite containing a small amount of lead carbonate. plumboferrite A trigonal mineral, PbFe4 O7 ; black; at Jakobsberg, Sweden. plumbogummite A trigonal mineral, PbAl3 (PO4 )2 (OH)5 .H2 O ; crandallite group; forms yellow to brown encrustations; in Cumberland, United Kingdom. plumbojarosite A trigonal mineral, PbFe6 (SO4 )4 (OH)12 ; alunite group; forms minute brown tabular crystals with rhombohedral cleavage. plumbomicrolite An isometric mineral, (Pb,Ca,U)2 Ta2 O6 (OH); pyrochlore group. It occurs in greenishyellow and orange masses and octahedra from Kivu, Zaire. plumbous Of, pertaining to, or containing lead, esp. in its lower valence. CF: plumbic plumb pneumatic jig Mineral concentrator in which air is pulsed upward through a porous deck by means of a rotary valve. Pryor, 3 plumb post One of the vertical posts at the side of a tunnel resting on sills and carrying the wallplates; collectively, they support the tunnel roof by means of centering. Stauffer plumites 2385

A feathery variety of jamesonite. See also: plumose antimony plummet See: plumbline plumose Having a feathery appearance. Fay plumose antimony A feather-ore variety of jamesonite or boulangerite; also called feather ore. Also spelled plumites, plumosite. plumose mica A feathery variety of muscovite. plumosite A feathery variety of jamesonite or boulangerite. plump Corn. A corruption of the word pump. plum-pudding stone See: puddingstone plunge a. The vertical angle between a horizontal plane and the line of maximum elongation of an orebody. b. The inclination of a fold axis or other linear structure, measured in the vertical plane. CF: apparent plunge; dip. AGI c. To set the horizontal cross wire of a theodolite in the direction of a grade when establishing a grade between two points of known level. AGI d. To reverse the direction of the telescope of a theodolite by rotating it 180 degrees about its horizontal axis. Syn: transit plunger a. In blasting, a rod designed for thrusting into a drill hole and ascertaining the position of a cartridge. Standard, 2 b. The piston of a force pump. Fay c. A piston and its attached rod. Long 2386

plunger bucket A pump piston without a valve. Also called plunger lift. Webster 3rd plunger case The pump barrel, or cylinder, in which a solid piston or plunger works. Also called pole case. Fay plunger jig washer A washer in which water is forced upward and then downward through a screen by the action of a plunger in an adjoining compartment. Although these machines are still in use, the term "jig washer" is now applied to the fixed-screen, air-pulse jig, which is directly descended from the first Baum washer used in 1892. See also: jig washer; pneumatic jig. Nelson plunger lift Scot. A pump and attached column of pipes, that raises water by means of a ram or piston. Fay plunger press A press in which the pressure is applied by a plunger, with a reciprocating motion, to charges of feed contained in molds in a vertical or horizontal table. BS, 5 plunger pump a. Reciprocating pump used for moving water or pulp, in which a solid piston displaces the fluid. Pryor, 3 b. A displacement-type pump may be of various types, such as: (1) the triplex pump, a vertical or horizontal, single-acting plunger type for small heads with three single-acting cylinders in the pump frame driven by a motor mounted on the outside of the frame and connected to the crankshaft of the pump through gearing; (2) the quadruplex or quintuplex pump, a pump having four or five cylinders; and (3) the duplex pump, a crank-and-flywheel type for high heads, with double-acting plungers. Lewis plunger-type washbox A washbox in which pulsating motion is produced by the reciprocating movement of a plunger or piston. Syn: piston-type washbox plus distance 2387

Fractional part of 100 ft or m used in designating the location of a point on a survey line-such as, 4+47.2, meaning 47.2 ft or m beyond Station 4; or 447.2 ft or m from the initial point, measured along a specified line. Seelye, 2 plush copper ore See: chalcotrichite; cuprite. plus mesh The portion of a powder sample retained on a screen of stated size. Osborne plus sight See: backsight pluton A body of medium- to coarse-grained igneous rock that formed beneath the surface by crystallization of a magma. plutonic a. Pertaining to igneous rocks formed at great depths. CF: hypabyssal AGI b. Pertaining to rocks formed by any process at great depth. Syn: abyssal; deep seated; hypogene. AGI plutonic metamorphism Deep-seated regional metamorphism at high temperatures and pressures, often accompanied by strong deformation; batholithic intrusion with accompanying metasomatism, infiltration, and injection (or, alternatively, differential fusion or anatexis) is characteristic. CF: injection metamorphism plutonic ore deposit Collectively, the major group of ore deposits of magmatic origin that have been formed under abyssal conditions. Schieferdecker plutonic rock Igneous rock formed deep within the Earth under the influence of high heat and pressure, hypogene rocks; distinguished from eruptive rock formed at the surface. Hess plutonic series 2388

A series of different igneous rocks that evolved from the same original magma through various differentiation stages. plutonism a. The obsolete belief that all of the rocks of the Earth solidified from an original molten mass. CF: neptunism b. A general term for the phenomena associated with the formation of plutons. AGI pluviometer See: rain gage ply a. U.K. A thin band of shale lying immediately over a coal seam. b. U.K. A rib or successive ribs; e.g., of clayband with very thin partings. c. Limy ply; a limestone bed; Edinburgh, U.K. pneumatic Set in motion or operated by compressed air. Nelson pneumatic blowpipe A long, 3/4-in-diameter (1.9-cm-diameter) metal pipe, connected to an air supply; used to blow out dust and chippings from vertical blast holes at quarries. The blowpipe is generally used for holes exceeding about 12 ft (3.66 m) deep. A stream of water is sometimes used instead of an air jet. Nelson pneumatic caisson Closed casing in which air pressure is maintained equal to the pressures of the water and soils on the outside. The deeper the caisson, the higher the pressure that must be maintained. Carson, 1 pneumatic cartridge loader A cartridge loader widely used for underwater blasting, for blasting without removing the overburden, and for long-hole blasting. It is also being used increasingly for tunneling and other sorts of rock blasting. Langefors pneumatic cleaning

2389

Mineral cleaning by machines that utilize air currents as the primary separating medium. The air machines can generally be divided into three types: (1) pneumatic jigs, in which the air current is pulsated; (2) pneumatic tables, in which the refuse is diverted from the direction of flow of the clean mineral by a system of riffles fixed to the deck; and (3) pneumatic launders, in which the products are flowing in the same direction, and the clean mineral is skimmed off the top of the bed and/or the refuse is extracted from the bottom in successive stages. Mitchell pneumatic concentrator Gravity jig, shaking table, or other device in which suitably ground minerals are separated by gravity during their exposure to a continuous or pulsating current of air. Pryor, 3 pneumatic conveying Use of compressed air to move fairly fine aggregates laterally and/or vertically. Pryor, 3 pneumatic conveyor a. A pipe or tube through which granular material is transported by airblast. It is used for pulverized coal, crushed rock (pneumatic stowing), cement, etc. The term could also be applied to a conveyor operated by compressed air. Nelson b. An arrangement of tubes or ducts through which bulk material or objects are conveyed in a pressure and/or vacuum system. pneumatic drill Compressed-air drill worked by reciprocating piston, hammer action, or turbo drive. Pryor, 3 pneumatic drill leg See: air-leg support pneumatic filling A filling method in which compressed air is utilized to blow filling material into a mined-out stope. Stoces pneumatic flotation cell Machine in which the air used to generate a mineralized froth is blown into the cell, either through a porous septum at or near the bottom, or by pipes that bring low-pressure air to that region. Pryor, 3 2390

pneumatic friction clutch This clutch transmits power through friction shoes carried on the tube of cord and rubber construction. The pneumatic clutch is self-adjusting for wear owing to the natural resilience of the rubber tube. Disengagement is complete and automatic when the air under pressure is released. The clutch is controlled by finger pressure on a valve. The valve can be installed at the place most convenient for the operator. Pit and Quarry pneumatic hammer A hammer that uses compressed air for producing the impacting blow. pneumatic hoist A device for hoisting; operated by compressed air. Standard, 2 pneumatic injection A method for fighting underground coal fires. This air-blowing technique involves the injection of an incombustible mineral, like rock wool or dry sand, through 6-in (15.2-cm) boreholes drilled from the surface to intersect underground passageways in the mines. pneumatic jig a. Air jig used in desert countries for concentrating ore. Pryor, 3 b. A jigging machine in which an airblast performs the work of separation of minerals. Standard, 2 c. See: Kirkup table; plunger jig washer. pneumatic lighting a. Underground lighting produced by a compressed-air turbomotor driving a small dynamo. Pryor, 3 b. The use of compressed air to generate electric light. See also: air turbolamp pneumatic lubricator See: line oiler pneumatic method In flotation, a method in which gas is introduced under slight pressure near the bottom of the flotation vessel, the device used for introduction being either a submerged pipe or a porous cloth, frit, or rubber surface forming the wall of a wind box. Gaudin, 2 pneumatic mortar 2391

Mortar applied to a surface with a cement gun in the same manner as gunite. Such mortar has a cube crushing strength of 3,000 psi (20.7 MPa) at 7 days and of 6,000 psi (41.4 MPa) at 28 days, with a water-cement ratio of 0.45. Hammond pneumatic pick A compressed-air-operated hand tool used to excavate coal, ore, and rock, with a punching action. Without the pick steel, its length is about 18 in (46 cm) and weight about 24 lb (10.8 kg). It delivers about 2,500 blows/min. The latest type is the watercontrolled pick, so designed that the air valve is operated by water pressure. The water assists in suppressing the dust made during cutting. Nelson pneumatic ram A ram fed by a compressed-air pipeline. The piston is about 8 in (20 cm) in diameter, giving an area of 50 in2 (323 cm2 ) and exerts a pushing force of up to 4,000 lb (1,800 kg). Nelson pneumatic riveter A compressed-air tool used for driving rivets. See also: rivet Hammond pneumatic rod puller An air-driven rod puller. See also: rod puller pneumatics The branch of physics that deals with the mechanical properties of gases, such as their pressure, elasticity, density, and also of pneumatic mechanisms; sometimes it includes acoustics. Standard, 2 pneumatic shaft sinking a. Shaft sinking with the aid of a drop shaft fitted with an air-tight deck to form a working chamber. See also: manlock b. The caisson-sinking process now largely obsolescent in mining practice. Nelson pneumatic stowing A system of filling mined cavities in which crushed rock is carried along a pipeline by compressed air and discharged at high velocity into the space to be packed, the intense projection ensuring a very high density of packed material. For stowing shallow workings--up to 200 yd (183 m) in depth--the stowing plant may be installed on the surface. The air pressure is about 60 psi (414 kPa). For deeper workings, the plant may 2392

be installed underground, and the crushed rock taken down from the surface. The stowing pipes are about 5 to 6 in (approx. 13 to 15 cm) in diameter. The system is often employed if important surface structures require protection. The material used is from old dirt heaps, screen dirt, and washery rejects. The material is crushed to -2-1/2 in (6.35 cm) and preferably without the -1/2-in (-1.27-cm) material. See also: air-stowing machine; crusher stower; hydraulic stowing; low-pressure air stower. Nelson pneumatic table An appliance for the dry cleaning of ore or coal. It consists of a perforated deck, with vertical ribs or riffles, which is reciprocated; the motion keeps the bed of raw coal sufficiently mobile for the blast of air from below to effect a process of stratification (or layering). The coal rises to the surface, with dirt at the base and a central layer of middlings. See also: Birtley contraflow separator; Kirkup table; Vee table; air table. Nelson pneumatic tamper Essentially a long-stroke piston with a mushroom-shaped foot about 4 in (10 cm) in diameter. It operates on compressed air, which is used to lift the piston and footpiece; their combined weight, in falling, supplies the impact. Carson, 1 pneumatic tool Tool operated by air pressure. Crispin pneumatic transport System composed of: a compressor, which provides airflow; a feeder, which meters the flow of material into a pipeline; and the pipeline-- for transporting coarse, dry, noncohesive material. SME, 1 pneumatic water barrel A special type of water barrel for removing water from a shaft sinking. By means of a hose connection to an air pump at the surface, a partial vacuum is created inside the barrel and the water lifts the valve and fills the barrel. The hose is then detached and the barrel is hoisted to the surface and discharged. Also called vacuum tank. Nelson pneumatogenic Said of a rock or mineral deposit formed by a gaseous agent. CF: hydatogenic; hydatopneumatogenic; pneumatolytic. AGI pneumatolysis 2393

Alteration of a rock or crystallization of minerals by gaseous emanations derived from solidifying magma. Adj: pneumatolytic. AGI pneumatolytic A term used in different connotations by various authors and perhaps best abandoned. It has been used to describe: (1) the surface effects of gases near volcanoes; (2) contactmetamorphic effects surrounding deep-seated intrusives; (3) that stage in igneous differentiation between pegmatitic and hydrothermal, which is supposed to be characterized by gas-crystal equilibria; and (4) very loosely, any deposit containing minerals or elements commonly formed in pneumatolysis, such as tourmaline, topaz, fluorite, lithium, and tin, and hence presumed to have formed from a gas phase. CF: pneumatogenic pneumatolytic metamorphism Contact metamorphism in which the composition of a rock has been altered by introduced gaseous magmatic material. pneumatolytic stage That stage in the cooling of a magma during which the solid and gaseous phases are in equilibrium. AGI pneumoA combining form taken from the Greek meaning lung, and used in connection with the terminology of geologic processes and effects involving gases and vapors. Stokes pneumoconiosis A disease of the lungs caused by habitual inhalation of irritant mineral or metallic particles. It occurs in any workplaces where dust is prevalent, such as mines, quarries, foundries, and potteries. Also called miner's asthma; miner's consumption; miner's lung. Also spelled pneumonoconiosis; pneumonokoniosis. CF: anthracosis; silicosis. See also: phthisis pneumokoniosis See: pneumoconiosis pocket a. A localized enrichment; a crevice in bedrock containing gold; a rich patch of gold in a reef. b. A rich deposit of mineral, but not a vein. c. A bin, of a capacity equal to the skip, 2394

used at the shaft bottom of an underground mine for quick and accurate skip loading. See also: shaft pocket; measuring chute. Nelson d. A receptacle, from which coal, ore, or waste is loaded into wagons or cars. Fay e. A ganister quarryman's local term for masses of rock, 30 to 50 ft (9.1 to 15.2 m) in width, that are worked out and loaded, leaving buttresses of untouched rock between them to support the upper masses. Fay f. A hole or depression in the wearing course of a roadway. Fay g. A local accumulation of gas. Hudson h. A bulge, sop, or belly in a lode or bed. See also: belly Arkell i. A cavity, whether filled with air, water, mineral, or gravel. Arkell j. In pegmatites, the central openings lined with crystals, including those of gem species. Sinkankas pocket-and-fender method In pillar extraction, a method in which lifts are mined in the same way as in the open-end method, except that a fender of coal or a series of small coal stumps is left adjacent to the gob as the lift is advanced. After the lift is completed, the fender or stumps of coal are blasted, and sometimes part of this coal is recovered. Woodruff pocket-and-stump method A method of mining pillars in which a narrow pillar of coal, called the stump, is left along the goaf (worked-out space) to support the roof while driving the pocket. This coal acts as a protection for the miners. When the pocket has been completed, the stump is worked back, then another pocket is driven, and so on. Lewis pocket compass A magnetic needle enclosed in a nonmagnetic case, the needle being free to swing over a graduated face or dial. The compass is useful for experimental purposes or for directionfinding in desolate parts of the countryside, or during darkness and foggy weather. Morris pocket conveyor A continuous series of pockets, formed of a flexible material festooned between crossrods, carried by two endless chains or other linkage that operate in horizontal, vertical and inclined paths. pocket hunter California. A miner or prospector who searches for small gold deposits which occur on the surface in the gold-bearing areas of the State. Fay pocket of gas

2395

A small accumulation of methane in a roof cavity, where it is beyond the reach of the ventilating air current. See also: deflector sheet; combustible gases layer; hurdle sheet. Nelson pocket transit See: Brunton compass pod A rudely cylindrical orebody that decreases at the ends like a cigar or a potato. See also: lens Podsol See: Podzol Podzol A great soil group in the 1938 classification system; a group of zonal soils having an organic mat and a very thin organic-mineral layer overlying a gray, leached A2 horizon and a dark brown, illuvial B horizon enriched in iron oxide, alumina, and organic matter. It develops under coniferous or mixed forests or under heath, in a cool to temperate moist climate. Also spelled Podsol. Spelled "podzol" when used as the soil type belonging to the Podzol group. Etymol: Russian podsol, ash soil. AGI podzolization The process by which a soil becomes more acid owing to depletion of bases, and develops surface layers that are leached of clay and develop illuvial B horizons; the development of a podzol. Also spelled: podsolization. AGI poecilitic The original spelling of poikilitic. Now obsolete in American usage, it is still the most accepted European spelling. AGI Poetsch process a. The original freezing process of shaft sinking developed by F. H. Poetsch in 1883. See also: freezing method b. A process in which brine at subzero temperature is circulated through boreholes to freeze running water through which a shaft or tunnel is to be driven during development of a waterlogged mine. Pryor, 3 poicilitic 2396

See: poikilitic poidometer An automatic weighing device for use on belt conveyors. The device feeds the material from a hopper in a uniform stream onto a short independent belt conveyor and from there onto the main belt or bin. The weight of material on the measuring belt actuates a scale beam that raises or lowers a gate controlling the rate of flow from the feed hopper to a certain predetermined load per foot of measuring belt. A meter records the travel of measuring belt, and this figure multiplied by the weight per foot of belt, as fixed by the scale beam adjustment, gives the weight of material handled in any given period. See also: weightometer poikilit See: bornite poikilitic A rock texture in which numerous grains of various minerals in random orientation are completely enclosed within a large, optically continuous crystal of different composition. Also spelled poicilitic. CF: ophitic poikilitic texture See: poikilitic poikiloblastic a. Said of a metamorphic texture in which small grains of one constituent lie within larger metacrysts. Modern usage favors this meaning. Syn: sieve texture b. Said of a metamorphic texture due to the development, during recrystallization, of a new mineral around numerous relicts of the original minerals, thus simulating the poikilitic texture of igneous rocks. CF: helicitic point a. A predetermined direction for driving a roadway underground. The point is fixed by roof plugs in the roadway. See also: alignment; spad. Nelson b. One one-hundredth (0.01) part of a carat. When less than one carat, the weight of a diamond is usually expressed in points; e.g., 20 points equals 1/5 carat. Chandler c. A pipe through which steam or hot water is brought into contact with frozen gravel to thaw it for mining or dredging. d. See: well point e. In quarrying, a type of wedge that tapers to a narrow, thin edge. f. The end or bottom of a borehole, as distinguished from the mouth or collar. Fay g. A tool used in trimming and smoothing rough stone surfaces. Webster 3rd h. Either of 2397

a pair of tapered rails at a turnout that can be adjusted to direct a set of mine cars from a straight rail track to another track branching off at an angle. See also: catch point; turnout. Nelson point agate See: point chalcedony point chalcedony White or gray cryptocrystalline quartz flecked with tiny spots of iron oxide, giving the whole surface a uniform soft red color. Syn: point agate point defect A deviation from ideal crystal structure about a point location; e.g., interstitial, atom missing (Schottky), or combined (Frenkel). CF: crystal defect; Frenkel defect; Schottky defect. point driver In metal mining, a person who drives steam or water points (specially made pipes with a chisel bit at one end) into the frozen ground of a placer deposit in advance of dredging operations, to thaw the ground so that it can be worked by the dredge for recovery of gold. Syn: thawing DOT pointed box A box, in the form of an inverted pyramid or wedge, in which minerals, after crushing and sizing, are separated in a current of water. See also: spitzkasten point group One of 32 geometrically possible arrays of symmetry elements intersecting at a point. These symmetry elements are axes of rotation, both proper and improper (1 = i, 2 = m). All minerals having the symmetry of one point group belong to the same crystal class. CF: symmetry; crystal class; space group. point kriging Estimating the value of a point from a set of nearby sample values using kriging. The kriged estimate for a point will usually be quite similar to the kriged estimate for a relatively small block centered on the point, but the computed kriging standard deviation will be higher. When a kriged point happens to coincide with a sampled location, the kriged estimate will equal the sample value. See also: kriging 2398

point of attack See: portal point of compound curvature The point of tangency common to two curves of different radii, the curves lying on the same side of the common tangent. Abbrev., P.C.C. Seelye, 2 point of curvature The point where the alignment changes from a straight line or tangent to a circular curve; i.e., the point where the curve leaves the first tangent. Abbrev., P.C. Seelye, 2 point of decalescence See: decalescence point of frog The intersection gagelines of the main track and a turnout. Kiser point of intersection a. The point where intersecting lines cross one another. Jones, 2 b. The point where the two tangents to a circular curve intersect. Abbrev., P.I. Also called vertex. Seelye, 2 point of recalescence See: recalescence point of switch That point in the track where a car passes from the main line onto the rails of a turnout. Kiser point of tangency The point where the alignment changes from a circular curve to a straight line or tangent; i.e., the point where the curve joins the second tangent. Abbrev., P.T. Seelye, 2 point plotting In seismology, a procedure in reflection interpretation in which depth points are computed and plotted for each seismogram trace separately. Schieferdecker 2399

point source A single point from which light emanates; e.g., the sun or a lamp filament, or their reflections. In the case of multiple reflections, each is a point source. poise a. The unit of absolute viscosity, equal to one dyne-second per square centimeter. Named from the physicist Poiseuille. AGI b. The second unit of fluid viscosity, often expressed in centimeters or grams. See also: absolute viscosity; Poiseuille's law. Pryor, 3 Poiseuille's law A statement in physics that the velocity of flow of a liquid through a capillary tube varies directly as the pressure and the fourth power of the diameter of the tube and inversely as the length of the tube and the coefficient of viscosity. See also: poise poisoning a. In ion-exchange terminology, loading of resin sites with unwanted ions, thereby eliminating them as locations for loading. Pryor, 3 b. Fouling of an organic solvent used in stripping pregnant leach liquor. Pryor, 3 Poisson's ratio The ratio of the lateral unit strain to the longitudinal unit strain in a body that has been stressed longitudinally within its elastic limit. It is one of the elastic constants. Symbol: sigma . CF: modulus of incompressibility poker man A laborer who removes blue powder and ash residue from retorts after molten zinc has been tapped. Also called scraper. DOT polar a. Lacking a center of symmetry, with the result that crystals are acentric in their crystal forms and physical properties; i.e., electrostatic or magnetic properties are equal and opposite at the opposite ends of these crystals; e.g., tourmalines. Ant. nonpolar. b. An optical device, such as nicol prism or polarizing filter, for the production of planepolarized light. See also: nicol; Nicol prism. Polar Ajax

2400

A high-strength, high-density, nitroglycerin gelatin explosive, supplied in both unsheathed and sheathed forms. See also: Ajax polar curve A graph showing the distribution of light in a flame safety lamp obtained by plotting the values obtained at intervals of 10 degrees around a full circle. Mason polar explosive Explosive containing an antifreeze ingredient and distinguished by the prefix polar. Polar and nonpolar explosives of equal grade possess similar characteristics. Explosives that contain nitroglycerin tend to freeze when stored at low temperatures for lengthy periods. Syn: low-freezing explosive polariscope An optical device consisting of two polarizers with a space between for a crystal or rock under study. Syn: stauroscope polarity In crystallography, the property of having differing types of termination at the two ends of a prismatic crystal. May be reflected in pyroelectric properties, conduction of electric current, etc. polarizability The property of an ion or atom to deform so as to create a dipole from the displacement of its electron cloud. polarization a. The difference between the equilibrium value of the potential of an electrode and the value attained when an appreciable current flows through a system. Schlain b. In electrolysis, the condition in the vicinity of an electrode, such that the potential necessary to get a desired reaction is increased beyond the reversible electrode potential. ASM, 1 c. The production of dipoles or higher-order multipoles in a medium. AGI d. The polarity or potential near an electrode. AGI e. In seismology, the direction of particle motion of shear (S) waves in a plane perpendicular to the direction of propagation. AGI f. A process of filtration or reflection by which ordinary light is converted to plane-polarized light in which the electric vector of a light ray is confined to a single plane. polarized light 2401

Light with its electric vector restricted to a plane or to an elliptically or circularly helical path as a result of filtration, reflection, or interaction with a crystal structure. polarizer In a polarized-light microscope, the polarizing filter or Nicol prism (polar) located below the sample stage. See also: nicol; analyzer. polarizing prism A prism of an anisotropic crystal, commonly calcite, cut and cemented together so as to permit passage of one of the doubly refracted light rays while reflecting the other out of the train of a microscope. Syn: Nicol prism polar moment of inertia The second moment of area about an axis perpendicular to its plane is known as the polar moment of inertia of a plane section. See also: moment of inertia Polaroid A sheet of cellulose impregnated with optically aligned crystals of quinine iodosulfate, which permit passage of light with its electric vector in one plane while absorbing all other impinging light. It is a cheap substitute for Nicol prisms in modern polarized-light microscopes. Polar Viking A typical nitroglycerin powder explosive, which is now supplied only in the sheathed form. McAdam, 2 polder Dutch. Low fertile land, as in The Netherlands and Belgium, reclaimed from the sea by systems of dikes and embankments. pole a. Either of the two regions of a permanent magnet or an electromagnet where most of the lines of induction enter or leave. A point toward which a freely suspended ferromagnetic rod aligns itself. b. The negative or positive electrical pole in a circuit. pole chain A surveyor's chain. See also: Gunter's chain 2402

pole figure A stereographic projection representing the statistical average distribution of poles of a specific crystalline plane in a polycrystalline metal, with reference to an external system of axes. In an isotropic metal; i.e., in one having a completely random distribution of orientations, the pole density is stereographically uniform; preferred orientation is shown by an increased density of poles in certain areas. ASM, 1 poleman See: locomotive brakeman pole piece A specially shaped piece of magnetic material forming an extension to a magnet; e.g., the salient poles of a generator or motor. CTD pole strength In measurement of magnetic strength, the number of unit poles in the measured field. One unit pole is the strength in a vacuum required to exert 1 dyn in a 1-cm gap between poles. Pryor, 3 polianite A steel-gray dioxide of manganese, MnO2 , crystallizing in the tetragonal system. It is distinguished from pyrolusite by its hardness and anhydrous character. CMD; Dana, 4 poling a. The act or process of temporarily protecting the face of a level, drift, cut, etc., by driving poles or planks along the sides of the yet unbroken ground. Used esp. for holding up soft ground. See also: forepoling b. A step in the fire refining of copper to reduce the oxygen content to tolerable limits by covering the bath with coal or coke and thrusting greenwood poles below the surface. There is a vigorous release of reducing gases that combine with the oxygen contained in the metal. If the final oxygen content is too high, the metal is underpoled; if too low, overpoled; and if just right, tough pitch. ASM, 1; CTD poling back Carrying out excavation behind timbering already in place. Hammond poling board 2403

a. A forepoling board, driven horizontally ahead to support the roof when tunneling through running ground. See also: forepoling b. In trenching, either of a pair of side boards wedged apart. Pryor, 3 polirschiefer Tripoli slate. Also called polishing slate. Dana, 1 polish An attribute of surface texture of a rock, characterized by high luster and strong reflected light, produced by agents, such as desert or glacial polish, or by artificial grinding and smoothing; e.g., marble or granite. AGI polished section A slice of rock or mineral that has been highly polished for examination by reflectedlight or electron microbeam techniques, a procedure mostly applied to opaque minerals. See also: thin section; reflected-light microscope. polished surface See: slickensides polishing Removing the last traces of suspended matter from solutions by passing them through a filter coated with diatomaceous earth or similar material. polishing cask A barrel in which grained gunpowder is tumbled with graphite to glaze it. Standard, 2 polishing mill A lap of metal, leather, or wood used by lapidaries in polishing gems. Fay polled stone Som. Stone hewn into shape and faced ready for building. Building stone with one side rough faced, as opposed to hammer-and-punch dressed. Arkell pollen peat Peat rich in pollen grains. Tomkeieff 2404

poll pick A pick with a head for breaking away hard partings in coal seams or knocking down rock already seamed by blasting. See also: hammerpick Fay pollucite An isometric mineral, (Cs, Na)2 Al2 Si4 O12 .H2 O ; zeolite group; forms a series with analcime; colorless; occurs in granite pegmatites; a source of cesium and a minor gemstone. Syn: pollux pollux See: pollucite polyA prefix signifying many. Used in many mineral names, such as polybasite, polycrase, polyhalite, and polyaugite. CCD, 2; Spencer, 5 polyargyrite A mixture of argentite and tetrahedrite. polybasite A monoclinic mineral (Ag,Cu)16 Sb2 S11 ; forms a series with pearcite; pseudohexagonal; soft; metallic; gray to black; sp gr, 6.0 to 6.2; in low-temperature veins; a source of silver. polychroilite Altered cordierite. Dana, 1 polychroism See: pleochroism polychroite See: cordierite polycrase

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An orthorhombic mineral, (Y,Ca,Ce,U,Th)(Ti,Nb,Ta)2 O6 ; black; in granite pegmatites. Formerly spelled polykras. polycrystal A mineral specimen composed of an assemblage of individual crystals of various crystallographic orientations. See also: glomerocryst; syntaxy. polycrystalline An aggregate of crystals of the same species. polydymite An isometric mineral, NiNi2 S4 ; linnaeite group; easily confused with violarite. polygenetic a. Resulting from more than one process of formation, derived from more than one source, or originating or developing at various places and times; e.g., said of a mountain range resulting from several orogenic episodes. AGI b. Consisting of more than one type of material, or having a heterogeneous composition; e.g., said of a conglomerate composed of materials from several different sources. CF: monogenetic polygon A plane figure bounded by straight lines. Jones, 2 polygonal A two-dimensional form having more than four regular straight sides. polygonal method An ore-reserve computation method in which an assumption is made that the area of influence of each drill hole extends halfway to the neighboring drill holes. Therefore, thickness and grade must vary uniformly in opposite directions and in such cases errors tend to be compensating. Where the thickness and grade vary in the same direction, the errors will accumulate and cause erroneous results. Krumlauf polyhalite A triclinic mineral, K2 Ca2 Mg(SO4 )4 .2H2 O ; bitter tasting; varicolored; occurs in salt deposits in Texas, New Mexico, and Germany. 2406

polykras See: polycrase polymer a. A compound formed by the union of two or more molecules of the same simple substance. Standard, 2 b. In the plural use, compounds identical in composition but which vary in molecular weight, such as ethylene (ethene), Ch2 :Ch2 ; propylene (propene), CH3 CH:CH2 ; and butylene (butene), CH3 CH2 CH:CH2 . Standard, 2 polymerization Union of two or more molecules of given structure to form a new compound with the same elemental proportions but with different properties and a higher molecular weight. Pryor, 3 polymerize To chemically combine small molecules into larger molecules; to undergo polymerization. polymetallic sulfide A sulfide deposit rich in copper, zinc, lead, silver, or gold, which forms as a result of hydrothermal activity in the vicinity of mid-ocean spreading centers or tectonically active basins. The first discovery of these deposits was from the French submersible Cyana, in 1979, during a joint international biological investigation of thermal springs on the deep seabed. The term derives from the French "sulfides polymetalliques." polymignite An orthorhombic mineral, (Ca,Fe,Y,Th)(Nb,Ti,Ta,Zr)O4 ; radioactive; in syenites and granite pegmatites. Also spelled polymignyte. polymorphism The characteristic of a chemical compound to crystallize in more than one crystal class; e.g.: (1) kyanite, andalusite, and sillimanite; (2) quartz, tridymite, cristobalite, coesite, and stishovite. Allotropy refers specif. to chemical elements crystallizing in more than one class; e.g., graphite, diamond, chaoite, and lonsdaleite. Polymorphism limited to two or three crystal classes is dimorphism or trimorphism, respectively. Individual species are polymorphs (dimorphs, trimorphs). Polytypism refers to variable stacking of identical layer structures in different crystal classes. Adj: polymorphic (dimorphic, 2407

trimorphic). Adv: polymorphous (dimorphous, trimorphous). Syn: pleomorphism trimorphism; isomorphism; isotypy; polysyngony. See also: allotropic polynigritite Variety of nigritite found in a finely dispersed state in argillaceous rocks. CF: keronigritite; humonigritite. Tomkeieff polynite A montmorillonoid clay mineral in soils. Spencer, 6 polyphase In electricity, having or producing two or more phases, such as a polyphase current. Syn: multiphase polysomatic Having a texture consisting of numerous small grains; said of minerals. Standard, 2 polysomatism Minerals having a texture of many small grains. polysyngony A condition where two or more minerals have the same composition, but different crystal classes owing to changed bond angles; e.g., alpha and beta quartz. CF: polytypy; polytropy; polymorphism. polysynthetic twinning a. Two systems of lamellar twinning at an angle with one another. b. Successive twinning of three or more individuals, according to the same twin law, with parallel composition planes; commonly revealed by visibly striated cleavage planes; e.g., albite twinning in plagioclase feldspar. CF: cyclic twinning; twin laminae. polythionic acid Any of several acids in a series related to sulfurous and thiosulfuric acid. Pryor, 3 polytropy

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A condition in which there is no change in the geometrical symmetry of the crystal structure of two related minerals, but a change to permit a variant in the resultant mineral; e.g., orthoclase microcline. CF: polytypy; polysyngony. Hess polytypism a. A condition in micas and similar clay minerals in which they show growth spirals which are due to lamellae of different orientations. AGI b. One-dimensional polymorphism resulting from alternate stacking of identical layers; e.g., kaolinite, nacrite, and dickite. Syn: polytypy polytypy A condition in which the space lattice of two related minerals is completely altered to a new type. This is illustrated by the quartz-tridymite relationship. See also: polytypism polytropy. Hess polyvinyl butyral A resin, with a plasticizer. Provides the interlayer in standard laminated glass made from either polished plate glass or window glass. Lee polyxene A variety of native platinum alloyed with iron. Poncelet wheel A kind of undershot waterwheel suitable for falls of less than 6 ft (1.8 m), having the buckets curved so that the water presses on them without impact. Ponsard furnace A furnace in which the escaping combustion gases, passing through tubular flues, heat the incoming air continuously through the flue walls. Fay pontil An iron rod used in glassmaking to carry and manipulate hot bottles, etc.; has a projection at the end, varying in shape according to the character of the ware carried. Also called snap; pontee; ponto; ponty; puntee; puntil; punty. Standard, 2 pontoon

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a. A float supporting part of a structure, such as a bridge. Nichols, 1 b. A wood platform used to support machinery on soft ground. Nichols, 1 pony set A small timber set or frame incorporated in the main sets of a haulage level to accommodate an ore chute or other equipment from above or below. Nelson pool a. To undercut or undermine material, such as coal, esp. in excavating. Webster 3rd b. A continuous area of porous sedimentary rock that yields petroleum or gas on drilling. Webster 3rd pool washing screen A screen that is divided into alternate transverse screen cloth panels and metal plate pool sections. Water is directed to the pools, setting up a swirling motion that agitates fines into suspension. See also: vibratory screen poor fumes Toxic or irritating chemicals produced by an explosion. Nichols, 1 poorly sorted See: nongraded sediment pop a. A short, secondary drill hole blasted to reduce larger pieces of rock or to trim a working face. Also called pophole; pop shot. See also: pop shot b. Explosion in sealed area of a mine. Manometers may record a sudden pressure rise due to such an explosion. Sinclair, 1 pop a boulder To place and explode a stick of dynamite on a boulder so as to break it for easy removal from a mine. Fay pophole A secondary drill hole. See also: pop pophole blasting 2410

Breaking down large pieces of asbestos by means of short blastholes judiciously placed. Sinclair, 7 pop-off valve A pressure-relief valve. Long poppet a. A pulley frame or the headgear over a shaft. A headframe. b. A valve that lifts bodily from its seat instead of being hinged. See also: poppet valve; puppet valve. poppet head a. The top of a derrick where the pulley is situated. Gordon b. See: headgear poppet valve A valve shaped like a mushroom, resting on a circular seat, and opened by raising the stem. See also: poppet; puppet valve. Nichols, 1 popping The drilling, charging, and firing of a hole in the center of a boulder at quarry and opencast mines. The hole is charged at the rate of 2 to 3 oz (57 to 85 g) of explosive per yd3 (74.2 to 111.3 g/m3 ) of rock. The charge is pushed to the bottom of the hole and then filled with sand or soil. Also called pop shooting. See also: snakeholing Nelson poppy stone Red orbicular jasper from California; popular for cutting en cabochon. pop-shooting A method of drilling a hole just beyond the center of a boulder to be broken so that the charge is centrally situated. Stemming is used. Pop-shooting is economical in explosives, but drilling is required. It is somewhat difficult to control the throw of broken material, but there is little noise to cause annoyance to nearby property owners. See also: secondary blasting pop shot a. In mining, a shot fired for trimming purposes. BS, 12 b. In quarrying, a method of secondary blasting. BS, 12 c. A shot by which a boulder in a mine is broken up by placing a stick of dynamite on top of the boulder and exploding it. Ricketts d. In 2411

blasting, an explosion of the charge that simply blows out the tamping. Syn: block hole shot pop valve A pressure-relief valve. Long porcelain clay A clay suitable for use in the manufacture of porcelain; specif. kaolin. AGI porcelain earth See: kaolinite porcelain jasper A hard, naturally baked, impure clay or porcellanite that, because of its red color, was long considered a variety of jasper. See also: porcellanite porcelain oven A firing kiln used in baking porcelain. Fay porcelaneous Resembling unglazed porcelain; e.g., said of a rock consisting of chert and carbonate impurities or of clay and opaline silica. Also spelled: porcellaneous; porcelanous. AGI porcellanite A dense siliceous rock having the texture, dull luster, hardness, conchoidal fracture, and general appearance of unglazed porcelain; it is less hard, dense, and vitreous than chert. The term has been used for: an impure chert, in part argillaceous; an indurated or baked clay or shale often found in the roof or floor of a burned-out coal seam; and a finegrained, acidic tuff compacted by secondary silica. Etymol: Italian porcellana, porcelain. Also spelled: porcelanite; porcelainite. See also: siliceous shale; porcelain jasper; haelleflinta. AGI pore A space in rock or soil not occupied by solid mineral matter. Syn: interstice; void. pore pressure 2412

See: neutral stress pore space The open spaces or voids in a rock taken collectively. See also: porosity; permeability. pore-space filling The deposition of minerals in the voids of rocks or between the grains of loose sediment. Nelson pore water a. In soil technology, free water present in a soil. Normally under hydrostatic pressure. The shear strength of adjacent soil depends on this pore pressure, which reduces frictional resistance and soil stability. b. Subsurface water in the voids of a rock. Syn: interstitial water pore-water pressure See: neutral stress porosimeter An instrument used to determine the porosity of a rock sample by comparing the bulk volume of the sample with the aggregate volume of the pore spaces between the grains. Porosimeters are of various designs, some using liquids and some using gases, at known pressures, to find the volume of openings. AGI porosity a. The ratio, P, expressed as a percentage of the volume, Vp, of the pore space in a rock to the volume, Vr, of the rock, the latter volume including rock material plus the pore space; P = 100 Vp/Vr. Holmes, 2 b. The amount of void space in a reservoir usually expressed as percent voids per bulk volume. Absolute porosity refers to the total amount of pore space in a reservoir, regardless of whether or not that space is accessible to fluid penetration. Effective porosity refers to the amount of connected pore spaces; i.e., the space available to fluid penetration. Syn: total porosity porosity coefficient Evolved by Professor H. Briggs in 1931 to express the conductance of a waste to air leakage, per foot length of the roadway per foot width of the leakage zone. Roberts, 1 porous 2413

Containing voids, pores, cells, interstices, and other openings, which may or may not interconnect. See also: porosity porous ground Any assemblage of rock material that, as a result of fracturing, faulting, mode of deposition, etc., contains a high percentage of voids, pores, and other openings. Long porous-pot electrode Nonpolarizable electrode consisting of a metal bar immersed in a saturated electrolytic solution which is contained in a porous pot. Schieferdecker porpezite A native alloy of argentiferous gold with palladium, the palladium content varying up to 10%. From Porpez, Brazil. Syn: palladium gold porphyrite An obsolete term synonymous with porphyry. The term was originally used to distinguish porphyries that contain plagioclase phenocrysts from those that contain alkali feldspar phenocrysts. AGI porphyritic a. Said of the texture of an igneous rock in which larger crystals (phenocrysts) are set in a finer-grained groundmass, which may be crystalline or glassy or both. Also, said of a rock with such texture, or of the mineral forming the phenocrysts. AGI b. Pertaining to or resembling porphyry. AGI porphyritic obsidian Volcanic glass having microcrystalline phenocrysts. porphyritic texture See: porphyritic porphyroblast A pseudoporphyritic crystal in a rock produced by metamorphic recrystallization. Adj: porphyroblastic. Syn: metacrystal; pseudophenocryst. AGI porphyroblastic 2414

a. Pertaining to the texture of a recrystallized metamorphic rock having large idioblasts of minerals possessing high form energy (e.g., garnet, andalusite) in a finer-grained crystalloblastic matrix. AGI b. See: pseudoporphyritic porphyroclast A rock fragment contained in mylonite. porphyroclastic structure See: mortar structure porphyrogranulitic Said of the texture of a diabase porphyry having phenocrysts of plagioclase and augite in a ground mass of plagioclase laths and augite. porphyroid Said of or pertaining to a blastoporphyritic or sometimes porphyroblastic metamorphic rock of igneous origin, or a feldspathic metasedimentary rock having the appearance of a porphyry. It occurs in the lower grades of regional metamorphism. AGI porphyry An igneous rock of any composition that contains conspicuous phenocrysts in a finegrained groundmass; a porphyritic igneous rock. The term (from a Greek word for a purple dye) was first applied to a purple-red rock quarried in Egypt and characterized by phenocrysts of alkali feldspar. The rock name descriptive of the groundmass composition usually precedes the term; e.g., diorite porphyry. Obsolete syn: porphyrite. AGI porphyry copper deposit A large body of rock, typically porphyry, that contains disseminated chalcopyrite and other sulfide minerals. Such deposits are mined in bulk on a large scale, generally in open pits, for copper and byproduct molybdenum. Most deposits are 3 to 8 km across, and of low grade (less than 1% Cu). They are always associated with intermediate to felsic hypabyssal porphyritic intrusive rocks. Distribution of sulfide minerals changes outward from dissemination to veinlets and veins. Supergene enrichment has been very important at most deposits, as without it the grade would be too low to permit mining. AGI porphyry deposit 2415

a. A deposit in which minerals of copper, molybdenum, gold, or less commonly tungsten and tin, are disseminated or occur in a stockwork of small veinlets within a large mass of hydrothermally altered igneous rock. The host rock is commonly an intrusive porphyry, but other rocks intruded by a porphyry can also be hosts for ore minerals. b. A deposit, usually of copper, molybdenum, or tin, in igneous rock of any composition that contains larger crystals in a fine-grained groundmass. SME, 1 port a. In drilling, a cylindrical opening through the bit shank from which the circulating fluid is discharged at the bit face into the water ways. Long b. Any opening in a furnace through which fuel or flame enters or exhaust gases escape. ASTM portable aggregate plant A plant mounted so that it can be moved over the highways on its own mounting and that performs all the operations of a stationary plant, including crushing, scalping, secondary crushing, screening, washing, and sand separation. Some of these complete plants are mounted on one chassis; others have the more common operations on one chassis with the supplementary equipment on separate portable mountings. Pit and Quarry portable bucket loader Any of several types of self-propelled multibucket loaders that are considered suitable for miscellaneous light excavating work. These loaders dig their own path, and to do this, have various means of gathering the material to a point where it will be picked up by the buckets as they pass over the lower tumbler. While these loaders are usually used for reclaiming from stockpiles, they can, under favorable conditions, excavate from deposits. These machines always are mounted on crawler treads. Pit and Quarry portable concentric mine cable A double conductor cable with one conductor located at the center and with the other conductor strands located concentric to the center conductor with rubber or synthetic insulation between conductors and over the outer conductor. Syn: concentric mine cable portable conveyor a. A conveyor designed to be moved as a unit. It is commonly wheel mounted and may or may not be sectional. NEMA, 2 b. Any type of transportable conveyor, usually having supports that provide mobility. See also: boxcar loader; bucket loader; hatch conveyor; loading conveyor; movable conveyor; portable drag conveyor; roller conveyor; trimmer conveyor; unloading conveyor; wheel conveyor. portable crane 2416

A hoisting device carried by a frame mounted on wheels. Crispin portable crusher A crusher with temporary support foundations, so that it can be moved in sections, or it can be moved along roadways with minimum dismantling. SME, 1 portable drag conveyor A portable conveyor upon which endless drag chains are used as the conveying medium. Also a term sometimes applied to a portable flight conveyor. See also: drag-chain conveyor; portable conveyor. portable drill Any size drill outfit that is wheel-, skid-, or track-mounted so that it can be moved readily as a unit. Long portable electric lamp Self-contained lamp (such as a battery-operated lamp) that may be worn on the person or carried about freely. portable flame-resistant cable A portable cable that will meet the flame tests of the U.S. Mine Safety and Health Administration. portable loader A loading machine mounted on wheels or crawler tracks. See also: shovel loader portable mine blower A motor-driven blower (fan) to provide secondary ventilation into spaces inadequately ventilated by the main ventilating system; the air is directed to such spaces through a duct. portable mine cable An extra-flexible cable used for connecting mobile or stationary equipment in a mine to a source of electric energy where permanent wiring is prohibited or impractical. (A portable cable for mining service is not always extra flexible and is used also with portable as well as with mobile and stationary equipment.) 2417

portable parallel duplex mine cable A double or triple conductor cable with conductors laid side by side without twisting, with rubber or synthetic insulation between conductors and around the whole. The third conductor, when present, is a safety ground wire. portable pneumatic core sampler A device developed by the U.S. Navy Ordnance Laboratory for sampling coral and sand bottoms. It consists of a four-legged pyramidal frame about 8 ft (2.4 m) high, a pneumatic hammer with air supply and exhaust hosing, 400 lb (180 kg) of lead weight, an anvil, and a 4-ft-long (1.2-m-long) aluminum barrel with a driving head for cutting through coral. Hunt portable shunt A tub-changing arrangement for a tunnel face. See also: double-track portable switch portable substation See: transportable substation portable trailing cable A flexible cable or cord used for connecting mobile, portable, or stationary equipment in mines to a trolley system or other external source of electric energy where permanent mine wiring is prohibited or is impractical. USBM, 2 portage Can. Trail between waterways. Hoffman portal a. The rock face at which tunnel driving is started. Syn: point of attack b. The surface entrance to a drift, tunnel, adit, or entry. c. The log, concrete, timber, or masonry arch or retaining wall erected at the opening of a drift, tunnel, or adit. portal crane A type of jib crane carried on a four-legged portal frame, which runs along rails. See also: goliath crane; platform gantry. Hammond portal-to-portal 2418

A term encountered in disputes over what constitutes compensable "working time" under Federal laws. Portal literally means "entrance" and, in underground coal mining, portal refers to the mine mouth or entry at the surface. Hence, portal-to-portal as a descriptive term means strictly elapsed time from entry through the portal to exit on return. BCI port crown Port roof of a tank. porte et gardin plow See: scraper plow porter A long iron bar attached to a forging, or a piece in process of forging, by which to swing and turn it. Standard, 2 porthole The opening or passageway connecting the inside of a bit or core barrel to the outside and through which the circulating medium is discharged. Long Portland beds See: Portland limestone portland cement A calcium-aluminum silicate produced by fusing or clinkering limestone and clay in a kiln so as to drive off carbon dioxide and produce an oxide glass. The clinker is ground very fine and, when mixed with water, will recrystallize and set. It is combined with aggregate to form concrete. The name is from a resemblance to the Portland limestone of England. portland cement mortar A mixture of portland cement, sand, and water. See also: cement mortar Nelson portlandite A hexagonal mineral, Ca(OH)2 ; occurs in skarns; an important constituent of portland cement. Portland limestone 2419

A series of limestone strata, belonging to the Oolite group (Upper Jurassic) on the Isle of Portland, Dorsetshire, England. Most of the building stone used in London is from these quarries. Portland stone a. A yellowish-white, oolitic limestone from the Isle of Portland (a peninsula in southern England), widely used for building purposes. AGI b. A purplish-brown sandstone (brownstone) from Portland, CT. AGI portrait stone A flat diamond, sometimes with several rows of facets around its edge; used for covering very small portraits. Standard, 2 posepnyte An oxygenated hydrocarbon from the Great Western mercury mine, Lake County, CA. It occurs in plates and nodules, sometimes brittle, occasionally hard; the color is light green to reddish-brown; and sp gr, 0.85 to 0.985. Fay position block Mining claim that is in a position to contain a lode if it continues in the direction in which it has been proved in other claims, but which itself has not been proved. positive a. Electrically, a point at a relatively high potential with respect to another point. A positive ion is one in which a particle, molecular or atomic, has ceased to be neutral owing to loss of one or more electrons. Pryor, 3 b. Positive ore is ore that has been proved to exist by being blocked out in panels sampled at close intervals on all four sides so as to establish its quality and quantity beyond reasonable doubt. positive confining bed The upper confining bed of an aquifer whose head is above the upper surface of the zone of saturation; i.e., above the water table. Little used. AGI positive crystal An optically positive crystal. AGI positive derail 2420

A device installed in or on a mine track to derail runaway cars or trips. This device is held open by a spring, necessitating that a worker hold it closed while a trip passes over it. Hess positive-discharge bucket elevator A spaced bucket-type elevator in which the buckets are maintained over the discharge chute for a sufficient time to permit free gravity discharge of bulk materials. See also: bucket elevator positive displacement pump A pump which discharges the same amount of water for a given power, regardless of the head against which it operates. See also: bladder pump positive drive A driving connection in two or more wheels or shafts that will turn them at approx. the same relative speeds under any conditions. Nichols, 1 positive element A large structural feature or area that has had a long history of progressive uplift; also, in a relative sense, one that has been stable or has subsided much less than neighboring negative elements. AGI positive elongation Tabular, lathlike, or needle crystals with the electric vector of their slow ray parallel to the long direction of the crystal. Syn: length slow positive ore a. Ore exposed on four sides in blocks of a size variously prescribed. Syn: ore developed Fay b. Ore which is exposed and properly sampled on four sides, in blocks of reasonable size, having in view the nature of the deposit as regards uniformity of value per ton and of the third dimension, or thickness. Fay positive rake The orientation of a cutting tool in a manner, so that the angle formed by the leading face of the tool and the surface behind its cutting edge does not exceed 90 degrees ; e.g., teeth in a ripsaw. Syn: gouge rake See also: gouge angle CF: rake positive ray 2421

Stream of positively charged atoms or molecules that take part in the electrical discharge in a rarefied gas. Positive rays have been studied by allowing them to pass through a perforated cathode onto a photographic plate, being deflected by magnetic and electrostatic fields (Thomson's parabola method) and by means of Aston's mass spectrograph. Syn: canal ray positive temperature coefficient See: temperature coefficient positron Positive electron of the same mass as a negative electron; has only transitory existence. Pryor, 3 possessio pedis The actual possession of a mining claim by the first arrival. possessory title Title vested in the locator of a mining claim by compliance with the State and Federal mining laws. possible crystal face Any crystal face permitted by the symmetry of crystal structure but not appearing on a particular mineral specimen. possible ore An obsolete term for inferred reserves. See also: reserve Syn: future ore post a. To bring the survey, maps, and records of a mine up to date. Fay b. A charge of ore for a smelting furnace. Webster 3rd c. Any of the distance pieces to keep apart the frames or sets in a shaft; a studdle. Webster 3rd d. A mine timber, or any upright timber, but more commonly used to refer to the uprights which support the roof crosspieces. Commonly used in metal mines instead of leg which is the coal miners' term, esp. the in the Western United States. Syn: upright e. A support fastened between the roof and the floor of a coal seam; used with certain types of mining machines or augers. f. A pillar of coal or ore. g. An item of kiln furniture. Posts, also known as props or uprights, support the horizontal bats on which ware is sent on a tunnel kiln car. Dodd h. A discrete portion of bond between abrasive grains in a grinding wheel or other abrasive article. When an 2422

abrasive grain held by a post has become worn, the post should break to release the worn grain so that a fresh abrasive grain will become exposed. Dodd i. A mass of slate traversed by so many joints as to be useless for building purposes. j. Any of the four vertical timbers of a square set. Lewis post-and-stall A mode of working coal, in which a certain amount of coal is left as pillars and the remainder is taken away, forming rooms or other openings. The method is also called bord-and-pillar; pillar-and-breast; etc. Fay post brake A type of brake sometimes fitted on a steam winder or haulage. It consists of two upright posts mounted on either side of the drum and operating on brake paths bolted to the drum cheeks. See also: winder brake Nelson post drill An auger (or drill) supported by a post. Fay post hole A shallow borehole. Long post-hole auger A hand-rotated drilling tool that enables bores to be sunk down to about 20 ft (6 m) in unsupported holes and deeper in cased holes. See also: shell-and-auger boring post-hole digger Large auger, rotated mechanically or by hand, used for digging in unconsolidated ground and retrieving a sample. Pryor, 3 posthumous In tectonics, said of a recurrence of forces and movement along lines or over areas affected by similar forces in a previous period; overprint. posting York. Extracting the post or pillars; pillar robbing. post jack 2423

A jack for pulling posts. See also: post puller Standard, 2; Fay postmineral movement Movement usually along a fault that occurs after a mineral has been deposited. postorogenic intrusion An igneous intrusion that took place after an orogenic event or cycle. post puller An electric vehicle having a powered drum for handling wire rope used to pull mine props after coal has been removed; used for the recovery of the timber. post puncher A coal-mining machine of the puncher type supported by a post. Fay post stone An English term for any fine-grained sandstone or limestone. Also spelled: poststone. AGI pot a. A vessel for holding molten metal. ASM, 1 b. An electrolytic reduction cell used to make such metals as aluminum from fused electrolyte. ASM, 1 c. Mud-filled stump of Sigillaria in an upright position in the roof of certain coal seams. The stump became hollow by decay of the central pithy part, the hollow being filled by mud. This stump is now a separate mass of shale and is liable for collaspse without warning. See also: caldron bottom; pot bottom. Nelson d. A colloquial syn. of seismic detector. AGI e. See: abyss; line oiler. potarite A tetragonal mineral, PdHg ; silver white. Syn: palladium amalgam potash Potassium carbonate, K2 CO3 ; formerly extracted from wood ashes; used as a component of glasses, glazes, and enamels to enhance colorants. Also called pearl ash. Syn: potassium carbonate potash alum 2424

See: kalinite; alum; potassium alum. potash feldspar See: potassium feldspar potash fixation The retention of potassium in clays either by chemical combination in clay minerals or by adsorption. AGI potash mica See: muscovite potash spar See: potassium feldspar; spar. CF: soda spar potash syenite A syenite with a large excess of potassium feldspar (microcline, orthoclase) or feldspathoid over sodium feldspar (albite). potassic Of, pertaining to, or containing potassium; relating to or containing potash. Standard, 2 potassium A highly reactive metallic element of the alkali group; it is soft, light, and silvery. Symbol, K. Occurs abundantly in nature; obtained from the following minerals: sylvite, carnallite, langbeinite, and polyhalite. The greatest demand is for use in fertilizers. Handbook of Chemistry and Physics, 3 potassium alum An isometric mineral, KAl(SO4 )2 .12H2 O . Syn: potash alum potassium aluminosilicate See: feldspar potassium apatite 2425

A synthetic phosphate with K replacing Ca. potassium bentonite A clay of the illite group, formed by the alteration of volcanic ash; a metabentonite. Syn: K-bentonite potassium carbonate See: potash potassium chloride See: sylvite potassium feldspar The minerals microcline, orthoclase, and sanidine. Syn: potash feldspar; potash spar; Kfeldspar; K-spar. potassium titanate This compound, which approximates in composition to K2 Ti6 O 13 and melts at 1,370 degrees C, can be made into fibers for use as a heat-insulating material. Dodd potato stone See: geode pot bottom A large boulder or concretion having the rounded appearance of the bottom of an iron pot and easily detached from the roof of a coal seam. See also: camel back; kettle bottom; tortoise. CF: caldron bottom; bell. Syn: pot; potstone. potch Inferior opal that does not exhibit play of color; found in association with precious opal (Australia). potential a. The words potential and voltage are synonymous and mean electrical pressure. The potential of a circuit, machine, or any piece of electrical apparatus means the voltage normally existing between the conductors of such a circuit or the terminals of such a 2426

machine or apparatus. In U.S. Bureau of Mines practice: (1) any potential less than 301 V shall be deemed a low potential; (2) any potential greater than 301 V but less than 651 V shall be deemed a medium potential; and (3) any potential in excess of 651 V shall be deemed a high potential. b. Any of several different scalar quantities, each of which involves energy as a function of position or of condition; e.g., the fluid potential of groundwater. AGI potential crater zone This is the region in which, if a sufficient quantity of explosive is used, the rock will be shattered and projected outward to form a crater. Leet, 2 potential-determining ion Any ion which leaves the surface of a solid immersed in aqueous liquid before equilibrium (saturation point) has been reached, while an electrical double layer is building up and zeta-potential develops. Pryor, 4 potential difference The difference in electric potential between two points; represents the work involved or the energy released in the transfer of a unit amount of electricity between them. AGI potential energy The form of mechanical energy a body possesses by virtue of its position. If a body is being dropped from a higher to a lower position, the body is losing potential energy, but if a body is being raised, then it gains potential energy. Morris potential gradient An ascending or descending value of voltage related to a linear measurement, such as a distance along the Earth surface or ground. USBM, 2 potential ore Inferred reserves. See: reserves potentiometric surface An imaginary surface representing the total head of ground water; defined by the level to which water will rise in a well. The water table is a particular potentiometric surface. Syn: piezometric surface; pressure surface. AGI pothole 2427

a. A kettlelike or circular depression, generally deeper than wide, worn into the solid rock in a stream bed at falls and strong rapids by sand, gravel, and stones being spun around by the force of the current. Also called a kettle hole; swallow hole. Fay b. A kettlelike to irregular steep-walled subcircular interruption of bedding in the Merensky Reef of the Bushveld Complex, South Africa. It is filled with younger material. c. A term used in Death Valley, California, for a circular opening, about a meter in diameter, filled with brine and lined with halite crystals. AGI d. An underground system of pitches and slopes. Applied in some cases to single pitches reaching the surface. e. A rounded, steep-sided depression resulting from downward surface solution. AGI f. The occurrence, in the nether roof of a coal seam, of an irregularly shaped mass generally broader at its base than elsewhere and with smooth sides (slickensides). TIME g. A circular or funnel-shaped depression in the surface caused by subsidence. Hudson h. A rounded cavity in the roof of a mine caused by a fall of rock, coal, ore, etc. i. A vertical pitch open to the surface. j. See: abyss pot kiln A small limekiln. Webster 3rd pot lead a. An obsolete term for graphite or black lead. AGI; Fay b. Graphite used on the bottoms of racing boats. potlid Eng. Flattened oval dogger of flaggy sandstone; so called because sometimes the upper or under layers, when split off, resemble potlids. CF: baum pot pot ore Foliated galena. Arkell pot setting In glassmaking, the placing of a pot in a furnace for the purpose of melting metal. Standard, 2 potstone a. Impure steatite or massive talc; used in prehistoric times to make cooking vessels. Also spelled pot stone. b. See: paramoudra potter 2428

A skilled craftsperson who fabricates ceramic ware using various forming techniques. pottern ore A term used in early metallurgical practice for an ore that becomes vitrified by heat, like the glazing of earthenware. Standard, 2 potter's asthma See: potter's consumption potter's bronchitis See: potter's consumption potter's clay A plastic clay free from iron and devoid of fissility; suitable for modeling or making of pottery or adapted for use on a potter's wheel. It is white after burning. AGI potter's consumption An acute bronchitis often occurring among pottery employees, eventually affecting the lungs. Standard, 2 pottery spar A 200-mesh feldspar produced for use by the manufacturers of chinaware, sanitary ware, ceramic tile, frits, enamel, glazes, electrical insulators, and vitrified grinding wheels. AIME, 1 potting The placing of pots, containing either potassium nitrate or sodium nitrate and sulfuric acid, in the kilns used in the manufacture of sulfuric acid from sulfurous acid obtained from the combustion of sulfur in air. Fay potty ore Som. Brown iron ore, Brendon Hills. Apparently a color term, since the two varieties of ore are black and potty. Arkell Poulter method

2429

A seismic technique that dispenses with the need for drilling shotholes. In this airshooting method, dynamite is exploded in arrays of simultaneous blasts with charges several feet above the ground. The principal difficulty involves the hazard of working with aboveground explosives and the damage to property or to the peace of mind of nearby inhabitants. Dobrin pounceon Wales. Underclay. Apparently a survival of the obsolete form of puncheon (punchin)--a supporting timber in a coal mine or in a building floor timber. Also spelled pounson. Arkell pound a. A large, natural fissure or cavity in strata. b. An underground reservoir of water. See also: lodge pound-calorie a. A hybrid term between the English and metric units and defined as the amount of heat required to raise 1 lb (0.454 kg) of water 1 degrees C. Newton, 1 b. An engineering heat unit, often called centigrade heat unit (chu). Defined as above. Approx. equal to 1.8 Btu (1.9 kJ). CTD pounder An ore-mill stamp. Standard, 2 pound-foot Unit of bending moment being the moment due to a force of 1 lb (0.454 kg) applied at a distance of 1 ft (30.48 cm). Hammond pour In founding: (1) the amount of material, as melted metal, poured at a time; and (2) the act, process, or operation of pouring melted metal; such as, make a pour at noon. Standard, 2 poured fitting A connecting device that is fastened to the end of a cable (wire rope) by inserting the cable end in a funnel-shaped socket, separating the wires and filling the socket with molten zinc. Nichols, 1 2430

pouring basin A basin on top of a mold to receive the molten metal before it enters the sprue or downgate. ASM, 1 pouring gate A channel in a mold through which to pour molten metal. Fay pouring pit refractory In the steel industry, refractory used for the transfer of steel from furnace to ingot. Refractories include ladle brick, nozzles, sleeves, stopper heads, mold plugs, hot tops, and mortars used for the brickwork involved. AISI pouty In glassmaking, a long iron rod for either drawing out glass or twisting it to a fine thread. powder A general term for explosives including dynamite, but excluding caps. Nichols, 1 powder barrel A barrel made for the conveyance of gunpowder, usually holding 100 lb (45.4 kg). CF: powder keg powder box A wooden box in a miner's breast or chamber, in which were kept black powder, cartridge paper, cartridge stick, squibs, lampwick, chalk, and tools. Syn: tool box powder carrier See: powder monkey powder chest A substantial, nonconductive portable container equipped with a lid and used temporarily at blasting sites for storage of explosives other than blasting agents. Unused explosives are returned to the magazine at the end of the shift. Syn: day box powdered coal 2431

Coal that has been crushed fine; may be transported by air to fire a boiler or industrial heating furnace. BCI powdered ore Aust. Ore disseminated with veinstuff. powder explosive An explosive containing still smaller quantities of liquid products, compared with plastic and semiplastic explosives, so that the spaces between the solid particles are not filled out entirely. As the result of this, the density of the mass is 20% to 40% lower than that of plastic and semiplastic explosives. Fraenkel powder factor The quantity of explosive used per unit of rock blasted, measured in lb/yd3 (kg/m3 ) per ton (metric ton) of rock. powder house A magazine for the temporary storage of explosives. See also: magazine powder keg A small metal keg for black blasting powder, usually having a capacity sufficient for 25 lb (13.5 kg) of powder. CF: powder barrel powderman a. A person in charge of explosives in an operation of any nature requiring their use. b. In bituminous coal mining and metal mining, one who handles proper storage of explosives in a powder house at a mine and issues powder, dynamite, caps, detonators, and fuses to miners as needed. At smaller mines, may deliver explosives to miners at working places. Also called powder monkey. See also: blaster powderman helper See: powder monkey powder metal As used in the diamond-drilling industry, the finely divided particles of iron, copper, nickel, zinc, tungsten carbide, etc., which, when mixed with a suitable binding material 2432

and subjected to processing by heat and pressure, may be used as a matrix material to form a bit crown. Long powder-metal bit Any diamond bit, mechanically set, in which finely divided metal powders are used as a matrix to hold the diamonds in place. Also called powder-pressed bit; powder-set bit; sinter bit; sintered-metal bit. Long powder metallurgy The art of producing and utilizing metal powders for the production of massive materials and shaped objects. ASM, 1 powder-metallurgy technique A metallurgical technique in which metal powder is pressed into a desired shape. powder-metal process The process of mechanically setting diamonds in a bit in a matrix of finely divided metal powders. The metal powder is first cold pressed to compact it in a bit mold or die and then heated to allow the bonding alloy to melt and bind the powder to the diamonds and bit blank. Hot pressing or coining follows heating of the powder in some modifications of the process. Long powder mine An excavation filled with powder for the purpose of blasting rocks. Fay powder monkey a. A person employed at the powder house of a coal mine whose duty is to deliver powder to the miners. b. In some metal mines, the person who distributes powder, dynamite, and fuses to the miners at the working faces. This is a nautical term, but is frequently used in the mining industry. c. In the quarry industry, one who carries powder or other explosives to the blaster and assists by placing prepared explosive in a hole, connecting a lead wire to a blasting machine, and performing other duties as directed. Also called blaster helper; powder carrier; powderman helper. See also: powderman powder pattern The array of monochromatic X-ray diffractions produced by a mineral powder. CF: crystallogram 2433

powder porosity Ratio of the volume of voids between particles, plus the volume of pores, to the volume occupied by the powder, including voids and pores. Pryor, 3 powellite A tetragonal mineral, CaMoO4 ; forms a series with scheelite as tungsten replaces molybdenum; a minor source of molybdenum in Idaho, Michigan, Nevada, and California, and Siberia, Russia. powellizing process A wood treatment consisting of impregnating the wood with a saccharin solution. It hardens the wood, and renders it fireproof to some extent. Liddell power a. Any form of energy available for doing any kind of work; e.g., steam power and water power. Specif., mechanical energy, as distinguished from work done by hand. Standard, 2 b. Used loosely to indicate the electric current in a wire. Fay c. Rate of doing work. The foot-pound-second (fps) unit of power is the horsepower (hp), which is a rate of working equal to 550 ft.lbf/s (745.7 W). The electrical power unit, the watt, equals 107 cm-gram-second (cgs) units; i.e., 107 erg/s or 1 J/s. CTD power arm The part of a lever between the fulcrum and the point where force is applied. Nichols, 2 power barrow See: pedestrian-controlled dumper power control unit One or more winches mounted on a tractor and used to manipulate parts of bulldozers, scrapers, or other machines. Nichols, 2 power control winch A high-speed tractor-mounted winch with one to three drums; used chiefly for operating bulldozers, scrapers, and rooters. Nichols, 1 power dragscraper 2434

A machine consisting of: (1) a bottomless scraper bucket; (2) a two-drum hoist; (3) two long cables that attach to the front and rear of the scraper; (4) a movable tail block; (5) a short, guyed mast located behind a ground hopper or other delivery point; and (6) two sheave blocks mounted on the mast to guide the operating cables to the hoist. The tail block is shifted manually from time to time, swinging the scraper in a wide arc until all the material within the operating radius has been taken out. Pit and Quarry power earth auger A mechanically operated auger for exploring and testing deposits that are not very hard. The drilling rig may be mounted on a lorry or on continuous tracks when greater depths may be reached. Nelson powered supports In fully mechanized coal mining, a system of pit props connected to a flexible armored conveyor by means of hydraulic rams. Pryor, 3 power factor a. The ratio of the mean actual power in an alternating-current circuit measured in watts to the apparent power measured in volt-amperes; equal to the cosine of the phase difference between electromotive force and current. Webster 3rd b. The ratio of the total watts input to the total root-mean-square volt-ampere input to a rectifier or rectifier unit. Coal Age, 1 c. A clause frequently found in electric power contracts, which sets forth that if a customer permits the average power factor of the load used to fall below a specified value, a penalty charge will be made. Power factor is often defined as the ratio of actual power to apparent power and is usually expressed as a percentage. Kentucky power-factor meter Meter that indicates the relation of the phase between the line current and the line voltage, which actually is the same as the power factor of the load. Coal Age, 3 power grizzly Power-operated machine used mainly for removing dirt and fines from material to be crushed. There are three main types--the live-roll grizzly, the vibrating-bar grizzly, and the bar grizzly feeder. See also: static grizzly power-operated supports See: self-advancing supports power pack 2435

a. In general, an electrically operated hydraulic pump, placed at the gate end, to supply power to face equipment; e.g., self-advancing supports. The system forms a closed circuit with the oil returning to a reservoir containing about 212 gal (800 L) of oil. The pump can supply 2-1/2 gal (9.5 L) of oil per unit at 2,000 psi (13.8 MPa), which allows a setting load of about 9 st (8 t) per prop. See also: hydraulic power Nelson b. A unit that converts AC or DC current to AC or DC voltages suitable for the operation of electronic equipment. NCB power rammer A manually operated compacting machine, weighing about 200 lb (91 kg), raised by an intrinsic internal combustion mechanism and allowed to fall by gravity. See also: mechanical rammer power sequence A sequence control system that is suitable for a group of conveyors in tandem. The trunk conveyor contactor is first closed; after a delay of from 3 to 15 s, sufficient for its motor to come up to speed, power is switched on to the contactor of the second conveyor; finally, after a similar delay, power is switched on to the third conveyor or conveyors. All power comes through the number 1 conveyor contactor so that, if this conveyor is stopped, all other conveyors in tandem stop as well. See also: sequence starting power shovel An excavating and loading machine consisting of a digging bucket at the end of an arm suspended from a boom, which extends cranelike from the part of the machine that houses the powerplant. When digging, the bucket moves forward and upward so that the machine does not usually excavate below the level at which it stands. See also: shovel loader power-shovel mining Power shovels are used for mining coal, iron ore, phosphate deposits, and copper ore. The shovels may be used either for mining or for stripping and removing the overburden, or for both types of work, although at some coal mines the shovels used for stripping are considerably larger than those used for other mining. Lewis power station An assemblage of machines and equipment, including the necessary housing, where electrical energy is produced from some other form of energy. Steam boilers are fed with coal or oil and the heat generated is used to produce high-pressure steam. The steam then passes to turbines that drive the generators and thus produce electricity. Nelson 2436

power takeoff A place in a transmission or engine to which a shaft can be attached so as to drive an outside mechanism. Nichols, 1 power tongs A mechanically powered wrench used to make up or break out a drill rod, casing, or pipe string. Long power train All moving parts connecting an engine with the point where work is accomplished. Nichols, 1 power unit a. Generally applied to any device used to drive or operate machinery around a mine. Specif., it is used for the motor-speed reducer combination used to drive belt and chain conveyors. Jones, 1 b. That part of a mining belt conveyor that consists of a power unit base, an electric motor, an electric controller, a speed reducer with a flexible coupling between motor and speed reducer, a power transmission device to power the drive pulley or pulleys, suitable covers for all moving parts and, if the power unit is of the detachable type, a device for attaching it to the conveyor. NEMA, 2 power upon the air In coal mine ventilation, the horsepower applied is often known as the power upon the air. This may be the power exerted by a motive column due to the natural causes, to a furnace, or it may be the power of a mechanical motor. The power upon the air is always measured in foot pounds per minute. Kentucky pozzolana a. A leucitic tuff quarried near Pozzuoli, Italy, and used in the manufacture of hydraulic cement. The term is now applied more generally to a number of natural and manufactured materials, such as ash and slag, that impart specific properties to cement. Pozzolanic cements have superior strength when cured and are resistant to saline and acidic solutions. Also spelled: pozzolan; pozzuolana; pozzuolane. See also: gaize b. A material that is capable of reacting with lime in the presence of water at ordinary temperature to produce a cementitious compound. Natural pozzolanas are siliceous material of volcanic origin. They include trass and Santorin earth. Blast furnace slag is used to produce artificial pozzolanas. CCD, 2 pozzolana cement 2437

A cement produced by grinding together portland cement clinker and a pozzolana, or by mixing together a hydrated lime and a pozzolana. Syn: Roman cement practical shot In coal mining, a shot for which a hole has been drilled in a direction selected with reasonable care and filled with powder and tamped with the same degree of care. Fay prairie soil Soil transitional between a pedalfer and a pedocal. Leet, 1 prase a. A translucent dull green or yellow-green variety of chalcedony. b. Crystalline quartz containing abundant hairlike crystals of actinolite. Syn: edinite; mother-of-emerald. praseodymium oxide A rare earth that, together with zirconia and silica, produces a distinctive and stable yellow color for pottery decoration. Dodd praseolite a. A green alteration product of iolite. Fay b. A greenish foliated alteration product of cordierite. prasopal A green chromium variety of common opal from Australia, Hungary, and Brazil. Also spelled prase opal. Pratt hypothesis A suggested type of hydrostatic support for the Earth's solid outer crust in which crustal density is supposed to be greater under mountains than under oceans. CF: isostasy; Airy hypothesis. Pratt truss See: N-truss Prayon process

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The most common phosphoric acid dihydrate process for phosphoric acid production using sulfuric acid with naturally occurring phosphate rock. Becker preaeration Aeration of water or ore pulp before treatment, notably by froth flotation where deoxygenated water is used (e.g., from under a frozen lake). Also used to stabilize ore pulp containing unstable sulfides before cyanidation. Pryor, 3 prebaked anode Anode produced by binding together crushed petroleum coke and coal-tar pitch in a mold under pressure; subsequently baked to 1,000 to 1,200 degrees C; used in a metallurgical electrical furnace and replaced as a unit when consumed; in the production of aluminum metal, the anode is attached to a metal rod. preblast Pertaining to the time period prior to the initiation of a blast. preblast survey Documentation of the existing condition of a structure prior to exposure to blasting vibrations. Precambrian shield Rocks older than the Cambrian age. Name refers to the great shield-shaped areas of ancient mineral-bearing rocks. These ancient rocks occur in many parts of the world. Cumming, 1 precementation process Grouting the strata to control ground water prior to the start of construction or excavation, such as shaft sinking. Precementation has been used in South Africa to depths of 4,000 ft ( 1,200 m) and considerable savings have resulted. See also: cementation sinking precious Descriptive of the finest variety of a gem or mineral. Syn: oriental; precious stone. precious garnet Brilliantly purple almandine. 2439

precious metal Any of several relatively scarce and valuable metals, such as gold, silver, and the platinum-group metals. ASM, 1 precious olivine See: peridot precious opal A gem variety of opal that exhibits a brilliant play of delicate colors by diffraction of light from close-packed 150- to 300-mm spheres of cristobalite-tridymite. The color of the bulk material may be black or white. CF: common opal precious serpentine A pale or dark oil-green, massive, translucent serpentine. Dana, 1 precious stone See: gemstone precious topaz a. Genuine topaz as distinguished from topaz-colored quartz (jewelers' topaz). b. An incorrect term for yellow to brown sapphire. precious tourmaline Dark-colored gem variety of tourmaline. precipitant Any agent, as a reagent, that when added or applied to a solution causes a precipitate of one or more of its constituents. Standard, 2 precipitate a. The operation, act, or process of adding a chemical or chemicals to an aqueous solution to react with a dissolved material in the solution and remove the resulting new solid matter by settling. b. The solids resulting from the precipitation process. precipitated sulfur 2440

Sulfur precipitated from calcium polysulfide solutions by hydrochloric acid and washed to remove all calcium chloride. precipitation a. The process of separating mineral constituents from a solution; e.g., by evaporation (such as halite or anhydrite) or by cooling of magma (to form an igneous rock). b. Exsolution. c. Water that falls to the surface from the atmosphere as rain, snow, hail, or sleet. It is measured as a liquid-water equivalent regardless of the form in which it fell. AGI precipitation barrier Metal-rich water, as it moves away from the source of the metal, ordinarily comes into an environment where changing conditions of some kind cause precipitation of part or all of the metal from the water. Precipitation barriers account for the more than normal decay of hydrochemical anomalies than can be accounted for by simple dilution. They characteristically occur in spring and seepage areas where groundwaters coming to the surface encounter an environment of increased availability of oxygen, sunlight, and organic activity. Hawkes, 2 precipitation hardening Hardening caused by the precipitation of a constituent from a supersaturated solid solution. See also: aging; hardening. ASM, 1 precipitation heat treatment Artificial aging in which a constituent precipitates from a supersaturated solid solution. See also: artificial aging; progressive aging. ASM, 1 precipitation process a. The manipulation of physical and/or chemical properties of a solution to cause one of the constituents of that solution to become insoluble. b. The treatment of lead ores by direct fusion with metallic iron or slag, or ore rich in iron; performed generally in a shaft furnace, rarely in a reverberatory. It is often combined with the roasting and reduction process. See also: iron-reduction process precipitator In beneficiation, smelting, and refining, a person who (1) tends zinc boxes in which gold or silver that has been dissolved in a cyanide solution is precipitated; and (2) precipitates gold from cyanide solution, except that the cyanide solution is agitated with zinc dust in 2441

a mixing cone and precipitate, then turned into a filter press where the precipitate is recovered prior to the drying and refining to secure the gold. DOT precision The degree of agreement or uniformity of repeated measurements of a quantity; the degree of refinement in the performance of an operation or in the statement of a result. It is exemplified by the number of decimal places to which a computation is carried and a result stated. Precision relates to the quality of the operation by which a result is obtained, as distinguished from accuracy, but it is of no significance unless accuracy is also obtained. AGI precision depth recorder A device for recording a sonic depth trace. Abbrev., PDR. Hy precision idler bearing A bearing having ground races and in which the bore and outside diameter tolerances are held to ten-thousandths of an inch and the width tolerance to thousands of an inch. NEMA, 2 precooler load The amount of sensible heat, removed from the air in precooling. Hartman, 2 precutting Method used in machine mining where a coal cutter makes a cut along the face in front of a cutter loader. It may be adopted in hard coal seams or where an improvement in the +2-in (+5.1-cm) coal product is required. Nelson precutting blade A special blade attached to a plow that operates a little in advance of the main blades of the machine. It may be used in hard coals or to prevent the climbing of the machine, which would leave a layer of coal on the floor. Nelson predicted 4-hour sweat rate An index devised by the Medical Research Council of Great Britain which is based on the rate of loss of sweat from the body. It is designed to measure the physiological effect of work in near limiting conditions in hot working places, and is based on the assumption that heat stress is a function of the rate of sweating. Roberts, 1 2442

predictive metallogeny See: mineral assessment preemption act An act providing for a patent to agricultural lands. The act does not include mineral deposits, as they are expressly reserved. preference A familiar term under the public land laws meaning exclusive. Ricketts preferential flotation a. A name applied to a special type of differential flotation in which a mixture of two flotative, sulfide minerals is given a slight roast so that one may be oxidized, and therefore not float, and the other remain unchanged. b. Preferential flotation may also be achieved by control of pH or by addition of an activating agent or depressant to the flotation mixer, conditioner, or cell. AGI preferential wetting Applied to froth flotation when separating fine coal from coal washery slurries. The slurry or mixture is treated with a reagent that has an affinity for the material to be recovered and that will lend itself to subsequent stages in the separation process. Nelson preferred orientation Feature of a rock in which the grains are more or less systematically oriented by shape. A schist in which the mica plates are parallel to one another shows a preferred orientation; so does a hornblende schist in which the long axes of the hornblende crystals are parallel. See also: orientation; unoriented. preformed rope Wire rope in which the strands are bent to their correct lay before being laid up, so that the rope is unlikely to spin or kink. Pryor, 3 pregnant solution A value-bearing solution in a hydrometallurgical operation. Pryor, 4 pregnant solvent 2443

In solvent extraction, the metal-bearing solvent produced in the solvent extraction circuit. pregs The liquor resulting from leaching of ore to dissolve a valuable constituent. Term connotes such a solution when it has reached a loading sufficient to justify its removal from contact with the ore, for separate treatment to reclaim the contained values (by precipitation, ion exchange, or stripping). After this treatment, the now barren solution is returned to work, or if foul, is run to waste or regenerated. Also called pregnant solution; royals. Pryor, 3 preheat To heat beforehand; as: (1) to heat (an engine) to an operating temperature before operation; and (2) to heat (metal) prior to a thermal or mechanical treatment. Webster 3rd preheat zone That portion of a continuous furnace through which the ware passes before entering the firing zone. ASTM prehnite An orthorhombic mineral, Ca2 Al2 Si3 O10 (OH)2 , in which Fe replaces Al; forms botryoidal or mammillary and radiating aggregates. Occurs in: hydrothermal veins, cavities, and amygdules in basalt; veins in felsic plutonic rocks; and low-grade metamorphic rocks. Commonly associated with zeolites. Syn: aedelite prehnitoid a. A variety of mizzonite resembling prehnite. Dana, 1 b. Impure prehnite. Dana, 1 preliminary exploration An investigation carried out along certain broad features of a coal or mineral area, with the object of deciding whether the proposition is such as to warrant a detailed or final exploration, which is often costly. Nelson preliminary prospecting Prospecting undertaken after scout prospecting has disclosed the existence of values. Preliminary prospecting helps to determine approx. the extent of the payable ground. Griffith 2444

preliminary soil survey A quick investigation of surface or near-surface conditions; no special equipment is employed. Tests are carried out on site for approximate classification of soil and are limited to visual or other simple tests. See also: detailed soil survey; general soil survey. Nelson premature blast The detonation of an explosive charge earlier than warranted. Premature explosion may be due to carelessness, accidental percussion, a faulty fuse, or degenerated explosives. See also: safety fuse; hangfire. Nelson; Pryor, 3 premature block An obstruction or block in a core barrel or bit that prevents the entry of core into the barrel before the bit can be advanced far enough to cut a length of core to fill the barrel. Long premature firing The detonation of an explosive charge or the initiation of a blasting cap before the planned time. Meyer premature set a. The hardening of cement in a shorter time than normal or estimated. Long b. This may be caused by the addition of catalysts to cement to increase setting time or by downhole temperatures and pressure that cause cement to set prematurely. premium tin Tin of such high purity as to rate a special bonus in the metal market. Pryor, 3 premix Aggregate that has been coated with bituminous binder before spreading. See also: penetration macadam; tarmacadam. Nelson preparation a. The treatment of ore or coal to reject waste. See also: concentration; ore dressing; preparation plant. b. The process of preparing run-of-mine coal to meet market specifications by washing and sizing. Jones, 1 2445

preparation boss In bituminous coal mining, a foreman who is in charge of the operations of washing and sizing coal for market at the washery plant. DOT preparation plant Strictly speaking, a preparation plant may be any facility where coal is prepared for market, but by common usage it has come to mean a rather elaborate collection of facilities where coal is separated from its impurities, washed and sized, and loaded for shipment. Syn: cleaning plant BCI preparatory work Mining operations to facilitate mining proper after having explored a deposit and having made it accessible both in strike and dip. This work is executed almost entirely within the deposit and includes making: (1) inclines and transfer stations with manways; (2) sublevel drives between the levels; and (3) various crosscuts, chutes, minor shafts, raises, winzes, and other works. Stoces prepare a. To shear or undermine coal so that it can be readily blasted loose. Fay b. Arkansas. To make a cartridge for a blast. Fay c. Arkansas. To charge a blasthole. Fay preplaning The lead or stagger that exists between planing blades in the same vertical plane of a plow. Nelson prereduced iron-ore pellet A semimetallized pellet developed by the U.S. Bureau of Mines from taconite concentrates. The process involves rolling the concentrates into pellets, then drying, calcining, and roasting the pellets in a reducing (oxygen-deficient) atmosphere. During the heat-hardening stage, the pellets are partly converted to metal. Use of these pellets causes a considerable increase in pig-iron production. See also: iron ore preselective An arrangement by which a gear level can be moved, but the resulting speed shift will not take place until the clutch or the throttle is manipulated. Nichols, 1 present 2446

Eng. Stone of suitable thickness for shaping into a tile stone without frosting; occurs in Stonesfield slate series and Chipping Norton limestone of the Cotswolds. Arkell present value a. The present value of a mine may be considered to be a sum of money that may be allowed for the purchase, development, and equipment of a mine, with the expectation of receiving for this capital expenditure, during the estimated life of the mine, the return of this capital plus a substantial profit commensurate with the risk involved in the venture. Hoover b. The present value of a property is the amount that, if invested now in its purchase, would find its repayment with commensurate profit in the estimated series of annual dividends. Actuarially, it is the discounted sum of each and all those dividends, after allowance for any estimated further capital expenditure on necessary works and equipment. Truscott preservative For mine timbers that are exposed to severe conditions of damp, ventilation, and stress, any of several chemicals used to impregnate them to resist dry or wet rot. These include copper sulfate, creosote, salt, sodium fluoride and silicofluoride, and zinc as chloride or sulfate. Pryor, 3 presplitting a. A smooth blasting method in which cracks for the final contour are created by blasting prior to the drilling of the rest of the holes for the blast pattern. Once the crack is made, it screens off the surroundings to some extent from ground vibrations in the main round. Langefors b. See: controlled blasting press cloth See: filter cloth pressed amber Synthetic amber produced by consolidating amber fragments under pressure with an oil binder. Syn: reconstructed amber; amberoid. pressed cameo Similar to molded cameo, but pressed. CF: molded cameo pressed copal

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Synthetic copal produced by consolidating copal fragments under pressure with an oil binder. presser In ceramics, a worker who molds the handle, ears, and decorative reliefs to be applied to a pottery vessel before firing. Fay pressing machine a. A machine that forms ceramic shapes by forcing plastic or semiplastic raw materials into a die or mold. b. A machine in which the whole forming operation is carried out by pressing the plastic glass by a plunger forced into a die or mold. The machine may be operated by hand or it may be fully automatic. CTD pressure a. The force exerted across a real or imaginary surface divided by the area of that surface; the force per unit area exerted on a surface by the medium in contact with it. AGI b. A commonly used short form for geostatic pressure. AGI c. As used in mine ventilation terminology, it is sometimes defined as the available energy content of the air and as the pressure difference between two points in a ventilation current as the energy lost due to friction between two points. Roberts, 1 d. Force exerted by air per unit area, either gage or absolute. Atmospheric pressure is measured by a barometer. Measured in pounds per square inch, kilopascals, or inches of mercury. Hartman, 1 pressure anemometer a. An instrument for measuring the velocity of ventilating air currents in mines. b. An anemometer indicating wind velocity by means of the velocity head exerted. Standard, 2 pressure arch The driving of a narrow roadway results in the development of a pressure arch over the excavation. The strata within the arch bend slightly and cease to support the overlying beds, and the load is transferred to the solid or rock along the sides. The wider the roadway, the greater the span of the arch and its height at the crown. A similar but larger pressure arch is formed across a longwall face, with one leg resting on the solid coal and the other on the solid pack behind the coal face. See also: abutment; arch structure; load transfer. Nelson pressure arch theory The pressure arch theory in roof action suggests that, when a narrow heading is advanced, the layers of rock in the immediate roof deflect slightly and relieve themselves 2448

of the load of the overlying strata by transferring it to the sides of the opening by means of a pressure arch. The arch width just short of that which the higher strata cannot span and transfer the load to the sides of the opening is called the maximum-pressure arch. The depth mainly influences the minimum width of the pressure arch, although the type of overburden also plays a part. The following formula has been developed for approximating the minimum width of the maximum-pressure arch (W = minimum width of arch, in feet; D = depth of coal from surface, in feet): W = 3[(D / 20) + 20]. The equation does not apply for overburden less than 400 ft (122 m) or more than 2,000 ft (610 m) thick. Coal Age, 3 pressure balancing When an area of a mine has been sealed off from the remainder of the workings by barriers or stoppings inserted at suitable points, it is important to prevent the circulation of air within the sealed area. This means that external air pressures must be equalized on all the seals. The object of equalizing the atmospheric pressures on the seals is attained by inserting or removing doors or brattice cloths at appropriate places. It is possible to make all the seals contiguous with a common airway by this means, so that, if they are not widely separated, they will be subjected to the same external atmospheric pressure. Roberts, 1 pressure block Pressure formed over the workings by masses of rock being severed from the surrounding formations, creating pressure on the pillars, walls, or other supports. Pressure blocks of large size may result from natural geological phenomena, such as faults, or may occur as a result of mining operations. Lewis pressure blower A machine or blower having either pistons, cams, or fans for furnishing an airblast above atmospheric pressure. Standard, 2 pressure bump An occurrence when a coal pillar suddenly fails on becoming overloaded by the weight of the rocks above it. Generally, the coal is forced with some violence into the roadways and other open spaces. See also: rock bump; rock burst; shock bump; bumps. Nelson pressure chamber a. An enclosed space arranged on the access side of a stopping, which seals off an area and is furnished with means of raising or lowering the air pressure within it. BS, 8 b. If the mine area to be sealed off is extensive, and the seals are widely scattered, the fact that they are subject to different pressures may be unavoidable. In this event, pressure 2449

chambers may be required on the outby side of seals. Pressure chambers are also of value when the seals cannot be made tight, because of broken or fissured ground. The principle consists of building an outer chamber by erecting a second stopping on the outby side of the seal. The air pressure in the intervening space is then controlled to prevent movement of air across the seal. Roberts, 1 c. A method of driving tunnels and sinking shafts through running sand by holding back the loose material by compressed air. The technique is no longer applied to any great extent in mining. See also: caisson sinking Nelson pressure creosoting The most effective method of preserving timber by impregnation with creosote under pressure in tanks. Hammond pressure detector See: hydrophone pressure die casting The usual die casting process in which the molten metal is forced into highly finished molds under heavy pressure by plungers, compressed air, or combined methods. Hammond pressure dome a. See: air dome b. The bonnet on a steam boiler. Long pressure drilling A process of rotary drilling in which the drilling fluid is kept under pressure in an enclosed system. Brantly, 1 pressure drop The decrease in pressure at which a liquid or gas is made to move between the intake and discharge of a pipeline or drill stem. Long pressure equalizer In drilling, a diaphragm connected to the fluid column by a series of ports incorporated in the design of some core barrels and preventing the entry of drilling fluids into the core-barrel-head bearings. Long pressure fan 2450

a. A fan supplying air under pressure. Webster 3rd b. A fan that forces fresh air into a mine as distinguished from one that exhausts air from the mine. Fay pressure figure The indistinct six-rayed star produced on a mica plate after pressing with a dull point. CF: percussion figure pressure filter a. A machine for removing solids from tailings; the effluent can be reused in the washery or plant. The tailings are pumped into the filter under pressure; filtration takes place and solids are deposited in the chambers. Gradually the resistance increases until a pressure of 100 psi (690 kPa) is necessary to force more tailings into the press. At this stage, the chambers are almost full of solids. The feed is cut off and the press opened to allow the cakes to fall onto the conveyor beneath the chambers. The output of the pressure filter is low. Nelson b. A filter in which pressure is applied to increase the rate of filtration. BS, 5 c. A filter in which the liquid to be filtered is forced through filtering material by a pressure greater than its own weight in the filter. pressure forging Forging done by a steady pressure, as in a hydraulic press. Standard, 2 pressure gage An instrument used to measure the force per unit area exerted by a confined fluid or gas. Long pressure grouting a. The act or process of injecting, at high pressures, a thin cement slurry or grout through a pipeline or borehole to seal the pores or voids in rock or to cement fragmented rocks together. Long b. Forcing a slurry of cement and sand into subgrade or an embankment either by use of compressed air or by hydraulic pressure. Urquhart pressure head The height of a column of liquid supported, or capable of being supported, by the pressure at a point in the liquid. See also: static head; total head. AGI pressure leaching In chemical extraction of valuable ore constituents, use of an autoclave to speed processing by means of increased temperatures and pressures. Pryor, 3 2451

pressure per diamond The feed pressure or load applied per diamond in a bit. The total load supported by the bit divided by the number of stones set in the bit face expresses the pressure per stone in numerical values. Also called diamond pressure; stone pressure. Long pressure plate In a clutch, a plate driven by the flywheel or rotating housing, which can be slid toward the flywheel to engage the lined disk or disks between them. Nichols, 1 pressure process Treatment of mine timber to prevent decay by forcing a preservative, such as creosote, zinc chloride, sodium fluoride, and other chemicals, into the cells of the wood. See also: timber preservation pressure-quantity survey See: ventilation survey pressure ring A ring about a large excavated area, evidenced by distortion of the openings near the main excavation. Shear cracks appear and minor slabbing of the rock takes place. Lewis pressure shadow The name sometimes applied to a fringe or halo differing from the groundmass that often accompanies a porphyroblast in a schistose rock. Hess pressure stripping The predominant means of extracting precious metal values from loaded activated carbon in the cyanidation process. Loaded carbon is placed in a pressure column along with a solution containing about 1% NaOH. This solution is circulated through the column at 150 degrees C until the precious metal values have been removed from the carbon absorbant. The loaded strip solution serves as the electrolyte for a subsequent electrowinning step for recovery of the precious metals. Van Zyl pressure surface See: potentiometric surface pressure survey 2452

An investigation to determine the pressure distribution or pressure losses along consecutive lengths or sections of a ventilation circuit. See also: ventilation planning; ventilation survey. Nelson pressure testing An indirect method of testing porosity and permeability of formations at elevations of proposed structures. pressure water loader A cartridge loader in which compressed water, rather than compressed air, is used for loading underwater. Langefors pressure wave A pressure produced by expanding gases moving at high velocity, the side component of which, equivalent to static pressure, may be recorded by a manometer at the side of the entry or mine passage. Syn: P wave; compressional wave. Rice, 2 pressure wire Wire leading from any of various points of an electric system to a central station, where a voltmeter indicates the potential of the system at the point. Webster 2nd pressurized a. Said of any structure, area, or zone fitted with an arrangement that maintains nearly normal atmospheric pressure. Nelson b. Said of any structure or area in which the pressure within is held higher than the outside pressure. prestressing The application of load to a structure so as to deform it in such a manner that the structure will withstand its working load more effectively or with less deflection. Hammond pretensioning The Hoyer method of prestressing concrete beams, precast in a workshop with the tensioned wires embedded in them and firmly anchored. Hammond preventive maintenance

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A system that enables breakdowns to be anticipated and arrangements made to perform the necessary overhauls and replacements in good time. previtrain The dense woody lenses in lignite that are equivalent to the vitrain in coal of higher rank. AGI priceite A triclinic mineral, Ca4 B10 O19 .7H2 O(?) ; earthy to porcelainous white; conchoidal fracture. Syn: pandermite pricking bar a. A bar used in opening the taphole of a furnace. Fay b. A rod used for removing obstructions from tuyeres and blowpipes. Fay priderite A tetragonal mineral, (K,Ba)(Ti,Fe)8 O16 ; cryptomelane group; red; easily mistaken for rutile in leucite rocks; occurs at Kimberley, Western Australia. priguinite See: iriginite prill In assaying, the bullion bead resulting from cupellation of an auriferous or argentiferous lead button. Pryor, 1 prillion Tin extracted from slag. Also spelled prillon. Standard, 2; Fay Primacord A fuse composed of an explosive core within a textile or plastic covering. It detonates every explosive that is in direct contact with it. Streefkerk Primacord-Bickford fuse A detonating fuse having an explosive of pentaerythritetetranitrate (PETN). Used in large-scale blasting work, esp. in quarries. Lewis 2454

primary a. Characteristic of or existing in a rock at the time of its formation; pertains to minerals, textures, etc.; original. Ant: secondary. b. Said of a mineral deposit unaffected by supergene enrichment. AGI c. Said of a metal obtained from ore rather than from scrap. Syn: virgin primary anomaly An anomaly formed by primary dispersion. primary basalt A presumed original magma, from which all other rock types are obtained by various processes of fractional crystallization. primary blast A blast used to fragment and displace material from its original position to facilitate subsequent handling and crushing. Atlas primary blasting The blasting of solid rock, ore, or coal; blasting in situ. See also: secondary blasting primary breaker A machine that takes over the work of size reduction from blasting operations; may be a gyratory or jaw breaker. Its capacity must be greater than the overall crushing plant capacity. In mines, primary ore crushing to about 7 in (18 cm) may be performed underground. See also: reduction ratio; tertiary crushing. Nelson primary breaking A stage in bituminous coal crushing that occurs at the entrance to a plant and consists of raw feed flowing into the primary breaker for reduction to a maximum top size of 4 in, 5 in, 6 in, or 8 in (10.2 cm, 12.7 cm, 15.2 cm, or 20.3 cm) either for washing or for other preparation purposes. Mitchell primary cell a. A group or bank of flotation cells in which the raw feed is given a preliminary treatment, either or both of the products being subsequently retreated. BS, 5 b. A cell that generates or makes its own electrical energy from the chemical action of its constituents; e.g., the voltaic cell, Deaniell cell, LeClanche cell, and dry cell. Morris 2455

primary clay A clay found in the place where it was formed. CF: residual clay; secondary clay. AGI primary coil a. The coil through which the inducing current passes in an induction coil or transformer. Webster 3rd b. A coil, forming part of an electrical machine or piece of apparatus, in which a current flows, setting up the magnetic flux necessary for the operation of the machine or apparatus. CTD primary creep Elastic deformation that is time-dependent and results from a constant differential stress acting over a long period of time. CF: secondary creep primary crusher a. The first crusher in a series for processing shale or other rocks. See also: secondary crusher b. In comminution of ore, a heavy-duty dry crushing machine capable of accepting run-of-mine coarse ore and reducing it in size to somewhere between 4 in and 6 in (10 cm and 15 cm). Heavy-duty connotes the ability both to handle large tonnages daily and to withstand very rough treatment. Pryor, 3 primary crushing In ore dressing, the first stage in which crushers take run-of-mine ore and reduce it to a size small enough to be taken by the next crusher in the series. Ordinarily, the Blake jaw crusher or a gyratory crusher is used. Newton, 1 primary crystal The first type of crystal that separates from a melt on cooling. ASM, 1 primary current distribution The current distribution in an electrolytic cell that is free of polarization. ASM, 1 primary dip See: original dip primary dispersion

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Geochemical dispersion of elements by processes operating within the Earth. CF: secondary dispersion primary drilling The process of drilling holes in a solid rock ledge in preparation for a blast by means of which the rock is thrown down. Fay primary environment See: geochemical environment primary excavation Digging in undisturbed soil, as distinguished from rehandling stockpiles. Nichols, 1 primary flat joint See: L-joint primary flow structure Structure of either linear or platy nature developed in igneous rocks prior to or during consolidation. Stokes primary fluid inclusion A fluid inclusion containing fluid trapped during original crystallization of its host mineral. AGI primary foliation The variety of platy flow structure that forms during crystallization of a magma and is due to the parallelism of platy minerals. Stokes primary gneiss A rock that exhibits planar or linear structures characteristic of metamorphic rocks, but lacks observable granulation or recrystallization, and is therefore considered to be of igneous origin. AGI primary gneissic banding Banding exhibited by certain igneous rocks of heterogeneous composition; produced by the admixture of two magmas only partly miscible or, in other cases, by magma 2457

intimately admixed with country rock into which it has been injected along bedding or foliation planes. CTD primary haulage A short haul in which there is no secondary or mainline haulage; e.g., a mine is started into a hillside, using mine cars, track, and hand loaders. An empty car is placed for the loader, and the loaded car is taken to the dump manually or by machine, repeating the process for each loader. See also: face haulage primary metal a. Metal produced: by direct smelting of ore; from a mine product, such as that extracted from mined ore; from reprocessing mine tailings; or from reprocessing smelter or refinery slags or residues. Camm b. Metal extracted from ores, natural brines, or ocean water. Also called virgin metal. Newton, 1 c. Ingot cast from reduced and perhaps refined metal as distinct from ingot containing recovered scrap metals. Pryor, 3 d. Metal recovered as a principal or byproduct material from the processing of ores; includes metal recovered from ore processing wastes such as tailings, and downstream processing wastes such as slags and residues from the smelting and refining of the metal. Excludes metal recovered from scrap or its processing wastes (secondary metal). primary mill A mill for rolling ingots or the rolled products of ingots to blooms, billets, or slabs. This type of mill is often called a blooming mill and sometimes a cogging mill. ASM, 1 primary mineral A mineral formed at the same time as the rock enclosing it, by igneous, hydrothermal, or pneumatolytic processes, and that retains its original composition and form. CF: secondary mineral AGI primary mineral deposit Syngenetic ore deposit. primary ore Ore that has remained practically unchanged from the time of original formation. Stokes primary ore mineral An ore mineral that was deposited during the original period or periods of metallization. The term has also been used to designate the earliest of a sequence of ore minerals, as 2458

contrasted with later minerals of the same sequence, which some writers have called secondary. To avoid confusion, Ransome proposed the terms hypogene and supergene. Hypogene, as the word implies, indicates formation by ascending solutions. All hypogene minerals are necessarily primary, but not all primary ore minerals are hypogene; e.g., sedimentary hematite is of primary deposition even though it formed as a low-temperature precipitate. primary phase The only crystalline phase capable of existing in equilibrium with a given liquid; it is the first to appear on cooling from a liquid state and the last to disappear on heating to the melting point. AGI primary reject elevator A refuse elevator that extracts the first or heavier reject; usually situated at the feed end of a washbox. BS, 5 primary relict A relict mineral that was a constituent of the original rock, whether igneous or sedimentary. Schieferdecker primary screen A screen used to divide coal (usually raw coal) into sizes more suitable for the subsequent cleaning of some or all of them. BS, 5 primary settling The surface subsidence that manifests itself a few months after mineral extraction and that usually constitutes 60% to 90% of the total subsidence. It varies according to the depth and thickness of the seam, the nature of the overburden, the mining method, and the thoroughness of the filling in the mined-out areas. The primary period is followed by the secondary period, in which the surface subsides gradually for a period of many years or even decades. Stoces primary shaft The shaft from the surface in which the first stage of hoisting is carried out. Spalding primary solid solution A constituent of alloys that is formed when atoms of an element B are incorporated in the crystals of a metal A. In most cases, solution involves the substitution of B atoms for 2459

some A atoms in the crystal structure of A, but there are cases in which the B atoms are situated in the interstices between the A atoms. CTD primary source An operation that produces or creates new dust. Hartman, 2 primary structure a. A structure in an igneous rock that originated contemporaneously with the formation or emplacement of the rock, but before its final consolidation; e.g., layering developed during solidification of a magma. AGI b. A primary sedimentary structure, such as bedding or ripple marks. AGI c. The structure preexisting the deformation and reequilibration associated with the emplacement at shallow depth of a metamorphic body of deep origin during an orogeny. CF: secondary structure primary washbox The first of a series of washboxes, which receives the feed and from which one product at least is given further treatment. BS, 5 primary washer The first of a series of washers, receiving raw feed, from which at least one product is retreated. BS, 5 primary water supply The principal or original source from which drilling water is obtained, as opposed to recirculated water. Long primary wave See: longitudinal wave primary zone Portion of a lode below that changed by leaching and secondary enrichment, and characteristic of the type of ore most likely to persist into the deeper levels of a mine. Pryor, 3 prime mover

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a. A machine that converts fuel or other natural energy into mechanical power. Nelson b. A tractor or other vehicle used to pull other machines. Nichols, 1 c. Any machine capable of producing power to do work. Shell primer a. A contrivance, such as a cap, tube, or wafer, containing percussion powder or other compound for igniting an explosive charge; ignited by friction, percussion, or electricity. Syn: percussion cap Webster 3rd b. The cartridge or that portion of a charge that carries a detonator or is coupled to Cordtex fuse and that detonates or sets off the remainder of the charge. The primer cartridge is placed at one end of the charge with the detonator pointing toward the charge. See also: direct initiation Nelson c. In blasting, the cartridge in which the cap is placed. Streefkerk d. Usually the combination of a dynamite cartridge and a detonating cap. Nichols, 1 primer cartridge The explosive cartridge into which a detonator has been inserted. BS, 12 primer charge A boosting charge placed in contact with a detonator to ensure detonation of the main charge. BS, 12 prime virgin mercury A term used for mercury produced by mines. prime western spelter See: prime western zinc prime western zinc Low grade of virgin zinc containing about 98% zinc, 1.60% lead, 0.08% iron, with no limitations on cadmium or aluminum. Bennett priming a. The act of placing a detonator in an explosive charge. Pryor, 3 b. The act of adding water to displace air, thereby promoting suction, as in a suction line of a pump. Water used to promote initial suction in a centrifugal or reciprocating pump. priming cartridge 2461

See: primer priming coat A coating of binder applied to a surface of natural compacted or stabilized soil before surface dressing. Nelson priming tube A tube containing fulminating powder for firing a charge. A detonator. Standard, 2; Fay priming valve a. A safety valve on the working cylinder of a steam engine to discharge the priming. Standard, 2 b. A valve connected with the discharge pipe of a force pump through which the pump may be primed. Fay primitive See: primitive circle primitive circle In crystallography, the great circle on a stereographic projection that represents the equator of the spherical projection. The poles of all vertical crystal planes plot on the primitive. Syn: primitive Fay primitive form A crystal form from which other forms may be derived; e.g., a hexoctahedron has six faces replacing each octahedral face. primitive unit cell See: unit cell princess Roofing slate sized 24 in by 14 in (61 cm by 36 cm). Pryor, 3 principal Primary, or leading function. A principal axis is the longest one in a crystal. The principal valence is that at which an element forms the greatest number of stable compounds. Pryor, 3 2462

principal axis a. In the tetragonal and hexagonal systems, the vertical crystallographic axis; hence what is the same thing in uniaxial crystals, the optic axis. In the orthorhombic and triclinic crystals, the axis of the principal zone; the axis with the shortest period, often the axis of the principal zone. In monoclinic crystals, the axis c, usually the axis of the principal zone excluding the symmetry axis; the symmetry axis b. Fay; AGI b. That crystallographic axis with unique symmetry in a crystal system, designated c, except in the monoclinic system where the second setting is used by mineralogists making b the unique axis. c. In a transducer used for sound emission or reception, a reference direction for angular coordinates used in describing the directional characteristics of the transducer. It is usually an axis of structural symmetry or the direction of maximum response, but if these do not coincide, the reference direction must be described explicitly. Hy d. In experimental structural geology, a principal axis of stress or a principal axis of strain. principal axis of strain One of the three mutually perpendicular axes of the strain ellipsoid. principal axis of stress One of the three mutually perpendicular axes that are perpendicular to the principal planes of stress. See also: principal axis principal meridian A central meridian on which a rectangular grid is based; specif. one of a pair of coordinate axes (along with the base line) used in the U.S. Public Land Survey system to subdivide public lands in a given region. It consists of a line extending north and south along the astronomic meridian passing through the initial point and along which standard township, section, and quarter-section corners are established. The principal meridian is the line from which the survey of the township boundaries is initiated along the parallels. AGI principal moment of inertia The moment of inertia of an area about either principal axis. Roark principal point The geometric center of an aerial photograph, or the point where the optical axis of the lens meets the film plane in an aerial camera. Symbol: p. See also: fiducial mark principal section 2463

a. In crystallography, the plane passing through the optical axis of a crystal. Standard, 2 b. The optical indicatrix of a biaxial mineral is a triaxial ellipsoid with semiaxes proportional to the refractive indices alpha, beta, and gamma. A principal section is an ellipse containing any two of these semiaxes. The indicatrix of a uniaxial mineral is an ellipsoid of revolution; its principal sections contain the axis of revolution which is proportional to the refractive index epsilon. principal stress The stress normal to one of three mutually perpendicular planes that intersect at a point in a body on which the shearing stress is zero. ASM, 1 principle of superposition To determine the stress in a member due to a system of applied forces, the system can be split up into several component forces and their moments and reactions added in order to calculate the total stress. Hammond principle of uniformity See: uniformitarianism Prins process A dense-media process in which large-size coal is separated from the refuse in a flowing bed of small coal in a reciprocating launder. Refuse sinks to the bottom. The small coal is screened from the coarse refuse and returned to the head of the launder by a drag conveyor. The floating large coal passes over skimmers in the trough to the discharge chute. Mitchell Prins washer A combination trough washer and jig in which the feed enters the unit through the central launder, where stratification takes place. The stratified material overflowing the stationary trough is divided at the first opening in the shaking jig, allowing the upper stratum of the material to flow onto the top deck of the jig while the lower stratum enters the jig reclean chamber. (Mitchell, 1950) priorite An orthorhombic mineral, (Y,Ca,Fe,Th)(Ti,Nb)2 (O,OH)6 ; now formally named aeschynite-(Y); forms series with aeschynite-(Ce) and with tantalaeschynite-(Y); black; forms with other rare-earth minerals in granite pegmatites and placers. Syn: blomstrandine 2464

prism a. The volume of a length of embankment or excavation. Seelye, 1 b. The liquid mobile volume of a stream. Seelye, 1 c. An open crystal form with faces and their intersecting edges parallel to the principal crystallographic axis. Prisms have three (trigonal), four (tetragonal), six (ditrigonal or hexagonal), eight (ditetragonal), or twelve (dihexagonal) faces. The nine-sided prisms of tourmaline are a combination of trigonal and hexagonal prisms. d. A long, narrow, wedge-shaped sedimentary body with width:thickness between 5:1 and 50:1; e.g., a bajada adjacent to an escarpment. It is typical of orogenic sediments formed during periods of intense crustal deformation; e.g., the arkoses found in fault troughs. CF: tabular Syn: wedge prismatic a. Descriptive of a clast with length to width ratio between 1.5:1 and 3:1. CF: tabular b. Pertaining to a sedimentary prism. c. Pertaining to a crystallographic prism. d. Descriptive of a crystal with one dimension markedly longer than the other two. e. Descriptive of two directions of cleavage. f. Descriptive of a metamorphic texture in which a large proportion of grains are prismatic and have approx. parallel orientation, giving a lineated appearance in hand specimens and thin sections. CF: equant See also: columnar prismatic compass A small magnetic compass held in the hand when in use and equipped with peep sights and a glass prism so arranged that the magnetic bearing or azimuth of a line can be read (through the prism) from a circular graduated scale at the same time that the line is sighted over. AGI prismatic plane Any crystallographic plane that is parallel to the principal axis of a crystal. prismatic quartz Collectors' name for cordierite. prismatic system See: orthorhombic system prismatic telescope A telescope having an eyepiece fitted with a prism that reflects at 90 degrees . Hammond 2465

prismoid Any solid, bounded by planes, whose end faces are parallel. Usually understood to include also figures whose bounding surfaces are warped surfaces. Seelye, 2 prismoidal Adj. of prismoid; used in sedimentary petrology (not prismatic, which is a crystallographic term). prismoidal formula A formula used in the calculation of earthwork quantities. It states that the volume of any prismoid is equal to one-sixth its length multiplied by the sum of the two end-areas plus four times the mid-area. CTD probability A statistical measure (where zero is impossibility and one is certainty) of the likelihood of occurrence of an event. AGI probable ore a. Indicated reserves. See: reserves b. A mineral deposit adjacent to developed ore but not yet proven by development. CF: extension ore probable performance curve A performance curve showing the expected results of a coal-preparation treatment. BS, 5 probable reserves Areas of coal or mineral believed to lie beyond the developed reserves but not yet proven by development. See also: economic coal reserves Syn: theoretical tonnage probe a. A small tube containing a sensing element of electronic equipment, which can be lowered into a borehole to obtain measurements and data. Long b. To conduct a search for mineral-bearing ground by drilling or boring. Long c. To lower drill rods, etc., to locate obstructions and/or to determine the attitude of a piece of junk in a borehole. Long probertite

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A monoclinic mineral, NaCaB5 O7 (OH)4 .3H2 O ; colorless; forms radiated columnar crystals; in Kern Country, CA. Syn: kramerite; boydite. probing Thrusting a pointed steel rod down through sand or soft clays to contact a seam or orebody. The point of the rod is examined for traces of coal or mineral. See also: auger proceedings The term proceedings is broader than the term action, yet in the mining law it is used in the sense of action and refers to the commencement of an action. It is used to enable a party to institute such proceedings under the different forms of actions allowed by the State and Federal courts. Ricketts process A series of operations conducted to achieve a result. Webster 3rd process company Company formed for the purpose of exploiting a patented process. Hoover process flowsheet A basic flowsheet indicating the main operational steps within a plant, the movement of the various materials between the steps, and the final products obtained, and often also the quantities of material with which the plant must be capable of dealing at various points. BS, 5 processing a. The methods employed to clean, process, and prepare coal and metallic ores into the final marketable product. Nelson b. The various artificial methods adopted for strengthening a soil, such as compaction, treatment with bitumen, lime, cement, etc. See also: stabilizer; soil stabilization. Nelson processioner An official land surveyor. Standard, 2 process lag In mineral processing, the delay or retardation in the response of the controlled variable at a point of measurement to a change in value of the manipulated variable. Fuerstenau 2467

process metallurgy Branch of metallurgy that deals with the recovery or extraction of metals from their ores. See also: extractive metallurgy process scrap The scrap arising during the manufacture of finished articles from iron and steel, and usually returned to steelworks after sorting and processing by scrap merchants. See also: capital scrap; circulating scrap. Nelson Proctor penetration needle A quick and convenient method for testing the resistance of a fine-grained soil to penetration at a standard rate of 1/2 in/s (1.27 cm/s). Needles from 1 to 0.05 in2 (6.5 to 0.3 cm2 ) area are used, and a spring balance indicates the pressure required for the needle to penetrate the soil. See also: penetration resistance; penetrometer; soil. Nelson prod cast See: impact cast prod mark a. An indicator of slip direction on a slickensided fault surface, consisting of a groove made by a clast. AGI b. A short tool mark oriented parallel to the current of a stream and produced by an object that plowed into and was then raised above the bottom; its longitudinal profile is asymmetric. The mark deepens gradually downcurrent where it ends abruptly (unlike a flute). CF: bounce cast Syn: impact cast produce a. The marketable ores or minerals produced by mining and dressing. b. Corn. The amount of fine copper in one hundred parts of ore. producer a. Person who extracts ore or coal from mines, rock from quarries, metals from ore by metallurgical processes, etc. See also: production b. A producing well. AGI c. A furnace or apparatus that produces combustible gas to be used for fuel; usually of the updraft type, which forces or draws air or a mixture of air and steam through a layer of incandescent fuel (such as coke) with the resulting gas consisting chiefly of carbon monoxide, hydrogen, and nitrogen. Webster 3rd d. An organism (e.g., most plants) that can form new organic matter from inorganic matter such as carbon dioxide, water, and soluble salts. AGI 2468

product Percent of metal in ore. Gordon production That which is produced or made; any tangible result of industrial or other labor. The yield or output of a mine, metallurgical plant, or quarry. See also: producer production checker In metal mining, a person who keeps a record of the number of containers (cars, buckets, or skips) raised to the surface, and the amount of ore contained in each, estimating or weighing the contents. DOT production gang A team of workers employed at the face on production, covering all face operations, maintenance, and supplies. Nelson productive Yielding payable ore. productive development The headings and levels excavated in a coal seam, preparatory to opening out working faces. These drivages are planned to prove and render accessible the maximum area of coal for the minimum yardage of development work. The modern trend is to make inthe-seam development as productive as possible with the aid of machines. See also: unproductive development Nelson productive land Land that has produced farm crops within the previous 5 years. Woodruff productivity a. A term closely allied with, and that may be expressed as, the output per manshift of a face or colliery or metal mine. Productivity will vary with the degree of mechanization and multishift working; it is also a function of the horsepower, of a suitable nature, at the disposal of each miner. See also: output b. The efficiency with which economic resources (workers, materials, and machines) are employed to produce goods and services. Crispin 2469

profile a. The outline produced where the plane of a vertical section intersects the surface of ground; e.g., the longitudinal profile of a stream, or the profile of a coast or hill. Syn: topographic profile b. A graph or drawing that shows the variation of one property such as elevation or gravity, usually as ordinate, with respect to another property, such as distance. AGI c. Cross section of a region of cylindrical folds drawn perpendicular to the fold axes. AGI d. In seismic prospecting, the data recorded from one shot point by a number of groups of detectors. AGI e. See: soil profile f. A vertical section of a water table or other potentiometric surface, or of a body of surface water. AGI g. A drawing used in civil engineering to show a vertical section of the ground along a surveyed line or graded work. Webster 3rd profile flying The technique of flying at a constant height above the ground during airborne mineral exploration. Generally, the aircraft maintains a height of 300 ft or 500 ft (91 m or 152 m) above the ground. This often involves a series of skillfully controlled climbs and dives over rolling ground. See also: vertical aerial photograph profile shooting A type of seismic refraction in which the shots and detectors are laid out on long straight lines. Successive shots are taken at uniform or almost uniform intervals along each line, and successive detector spreads are shifted about the same distance as the corresponding shot points so as to keep the range of shot-detector distances approx. the same for all shots. Generally, shots are received from opposite directions on each detector spread. The distance range is chosen so that the first, or where desired the second, arrivals will be refracted from a particular formation such as the basement or a high-speed limestone marker. The proper distance is usually determined from time-distance plots based on experimental shooting at the onset of the program. Dobrin profilograph An instrument for plotting the perimeter profile of an airway on a reduced scale, and primarily used when taking air measurements underground. profit When one speaks of the interest on a mining investment, the rate mentioned ordinarily consists of the normal rate plus a substantial additional rate that represents the profit that should accrue in proportion to the hazardous nature of the mining business. In this sense, the rate of interest in most forms of mining should be high; to be satisfied with less than 10% annually would show a lack of acumen. Hoover 2470

profit in sight Probable gross profit from a mine's ore reserves, as distinct from the ground still to be blocked out. proforma invoice Invoice that does not charge for goods marked, but shows cost details. Pryor, 3 prograde metamorphism Metamorphic changes in response to a higher pressure or temperature than that to which the rock last adjusted itself. CF: retrograde metamorphism progress chart A chart or graph forming a continuous record, which is kept up to date, of the amount of work done on a major project. It may take the form of a bar graph, divided into sections representing different jobs to be done, estimated and actual completion dates, etc. The chart covers the entire project from the initial site preparation or drivage to completion. Nelson progressing cavity pump See: Mono pump progressive aging In heat treatment, aging by increasing the temperature in steps or continuously during the aging cycle. See also: precipitation heat treatment progressive failure Rock or material failure in which the ultimate shearing resistance is progressively mobilized along the failure surface. ASCE project data Basic information needed by engineers concerned with design, site development, machine and housing assembly, plant erection, contract supervision, and coordination when planning, erecting, and bringing into operation a new mine and its attendant services, including the ore treatment plant. Pryor, 3 projected pipe 2471

A pipe laid on the surface before building a fill that buries it. Nichols, 1 projection a. In underground mining, a plan showing the proposed direction and location of entries, rooms, shafts, fans, and watercourses. Such projections commonly cover the entire property to be worked. b. A systematic, diagrammatic representation on a plane (flat) surface of three-dimensional space relations, produced by passing lines from various points to their intersection with a plane; esp. a map projection. AGI c. Any orderly method by which a projection is made; the process or operation of transferring a point from one surface to a corresponding position on another surface by graphical or analytical means, so that each point of one corresponds to one and only one point of the other. AGI d. See: exposure e. See: outcrop f. In mapping, a geometric (or mathematical) system of constructing the true meridians and parallels, or the plane rectangular coordinates on a map. Seelye, 2 g. A geometrically or mathematically derived portrayal of the surface of the geoid on a plane surface. The requirement for a particular projection is that it show the features of the surface of the Earth with a minimum of distortion of distances, directions, shapes, and areas. Hy h. The act or result of constructing a figure upon a plane or other two-dimensional surface that corresponds point for point with a sphere, a spheroid, or some other three-dimensional form. Fay projection balance Shows movement of a pointer by means of an illuminated scale. Pryor, 3 project plans A series of plans of a proposed new mine or reconstruction, which are drawn up for the purpose of obtaining approval of a project. BS, 7 prolapsed bedding A series of flat folds with near-horizontal axial planes contained entirely within a bed with undisturbed boundaries. prolong Secondary condenser used in the zinc industry. prong Eng. The forked end of a bucket-pump rod; used for attachment to the traveling valve and seat. Fay Prony's dynamometer 2472

A dynamometer for obtaining data for computing power delivered by turbines and other water wheels, or from the flywheel of an engine, or transmitted by shafting. Fay proof stress a. The stress that will cause a specified small permanent set in a material. ASM, 1 b. A specified stress to be applied to a member or structure to indicate its ability to withstand service loads. ASM, 1 propagate To transmit or spread from place to place; as coal dust propagates a mine explosion. propagated blast A blast consisting of a number of unprimed charges of explosives and only one hole primed, generally for the purpose of ditching, where each charge is detonated by the explosion of the adjacent one, the shock being transmitted through the wet soil. In this method, one detonator fired in the middle of a line of holes is capable of bringing about the explosion of several hundred such charges. Fay propagation a. The transfer of a signal through a medium; e.g., sound in air, seismic waves in fluids and solids, electromagnetic waves in a vacuum. b. In general, propagation is said to occur when the flame of an explosion travels over considerable areas of a mine in such manner as might result in loss of life of workers in the mine. Rice, 2 propagation velocity The speed of a wave in the material concerned, such as the propagation velocity of a detonation wave front traveling through an explosive or the propagation velocity of a seismic wave from a blast traveling through the ground. prop-crib timbering Shaft timbering with cribs kept the proper distance apart by means of props. Fay prop cutter In mining, a person who operates a power saw to cut to designated- and standard-length timbers and props used to support the walls and roofs of underground passageways and workplaces. Also called: prop sawyer; timber cutter. DOT prop drawer 2473

a. A sylvester or other appliance for withdrawing props from the waste area in coal mining. See also: monkey winch b. A worker who withdraws props and allows the roof to collapse. Props are withdrawn when caving of the roof is adopted. See also: timber robber Nelson propeller fan a. Axial-flow ventilating fan used to blow fresh air into mine workings or to extract foul air. Pryor, 3 b. A fan having an impeller, other than of the centrifugal-type, rotating in an orifice, the air flow into and out of the impeller not being confined by any casing. BS, 8 propeller pump This type of pump, often called axial-flow, develops most of its head by the propelling or lifting action of the vanes upon the liquid. These pumps are built in horizontal or vertical casings and are primarily used in handling sludge, dewatering pits, sewage pumping, and similar duties requiring large capacities and heads under 100 ft (30 m). Pit and Quarry propeller shaft Usually a main drive shaft fitted with universal joints. Nichols, 1 propel shaft In a revolving shovel, a shaft that transmits engine power to the walking mechanism. Nichols, 1 proper In crystallography, any symmetry rotation which does not change the chirality (handedness) of an asymmetric unit; e.g., not involving reflection or inversion. CF: improper proper proportion In a transparent gemstone, the proportion of the mass above and below the girdle, as well as the angles of the facets in relation to the girdle, that produces the greatest brilliancy from the particular species. These proportions vary with the refractive index of the gem species. properties of sections

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These include the cross-sectional area of a structural member, its moment of inertia, section modulus, and other geometrical properties essential for accurate design calculations. Hammond property One of the physical and chemical characteristics of a material. property man In bituminous coal mining, formerly one who kept record of location and has charge of distribution of coal cutting machines, drills, loaders, and other mechanical equipment in and about a mine. Now, one who oversees surface lands and structures. prop-free In longwall mining of a coal seam, a face with no posts between the coal and the conveyor used to remove it. Pryor, 3 prop-free front a. In coal mining, longwall working in which support to the roof is given by roof beams cantilevered from behind the working face. This leaves unobstructed room for digging and conveying equipment in a mechanized working. Pryor, 3 b. Such a face is necessary where armored flexible conveyors are used to carry a coal cutter or power loader. See also: link bar; self-advancing supports. Nelson prophylene-glycol dinitrate explosive An explosive containing the liquid ingredients named, in contradistinction to dynamite, which contains nitroglycerin. In commerce, the term dynamite is loosely used to include any mixture containing a liquid explosive. Fay proportion A statement of equality between two ratios. When one ratio is equal to another ratio, they are said to be in proportion. Jones, 2 proportional control action As used in mineral processing, action in which there is a continuous linear relation between the output and the input. Fuerstenau proportional counter 2475

A gas-filled, radiation-detection tube in which the pulse produced is proportional to the number of ions formed in the gas by the primary ionizing particle. ASM, 1 proportional limit The greatest stress that a material is capable of withstanding without deviation from proportionality of stress to strain (Hooke's law). In the case of rocks, this term and "elastic limit" are restricted to short-time tests; rocks may slowly and permanently deform in periods of long duration, even at stresses below the short-time proportional limit. proportional plus integral control action As used in mineral processing, action in which the output is proportional to a linear combination of the input and to the time integral of the input. Fuerstenau proportional plus integral plus derivative control action As used in mineral processing, action in which the output is proportional to a linear combination of the input, the time integral of input, and the time rate of change of input. Fuerstenau proportioning Measuring by weight or by volume the constituents, before mixing of concrete, mortar, or plaster. Hammond proppant Hydraulic fracturing and propping agent employed in the gas and oil industry to enable production from deep petroleum reservoirs. propping The setting of timber props in mine workings. Nelson prop retriever See: prop drawer prop sawyer See: prop cutter prop setter 2476

In anthracite and bituminous coal mining, a worker who installs props (posts) to support the roofs of underground working places, placing and wedging them at the most effective points. DOT prop wall Props that are fastened together in a group, like a fence, and placed against the walls to prevent the roof from caving into the stope. Stoces propylite A hydrothermally altered andesite resembling a greenstone and containing calcite, chlorite, epidote, serpentine, quartz, pyrite, and iron oxides. The term was first used by Richthofen in 1868. Propylite is common in mining districts of the Western United States, generally in the outermost subzone of hydrothermal alteration. See also: propylitization AGI propylitic alteration See: propylitization propylitization The result of low-pressure-temperature alteration around many orebodies. The propylitic assemblage consists of epidote, chlorite, Mg-Fe-Ca carbonates, and sometimes albiteorthoclase, all involved in partial replacement of wall-rock minerals. Syn: propylitic alteration See also: phyllic alteration prosopite A monoclinic mineral, CaAl2 (F,OH)8 ; forms tabular crystals or granular masses. prospect a. An area that is a potential site of mineral deposits, based on preliminary exploration. AGI b. Sometimes, an area that has been explored in a preliminary way but has not given evidence of economic value. AGI c. An area to be searched by some investigative technique, such as geophysical prospecting. AGI d. A geologic or geophysical anomaly, esp. one recommended for additional exploration. A prospect is distinct from a mine in that it is nonproducing. See also: prospecting e. A mineral property, the value of which has not been proved by exploration. Lewis f. To search for minerals or oil by looking for surface indications, by drilling boreholes, or both. Long g. A plot of ground believed to be mineralized enough to be of economic importance. Long h. Territory under examination for its mineral wealth. Prospecting is the search for deposits and is performed by aerial survey, magnetometry, surface examination, pitting, trenching, use 2477

of a prospector's pan, geochemical testing of soil, drilling (shallow or deep), seismic probe, and resistivity survey. Pryor, 3 i. The gold or other mineral obtained by working a sample of ore. j. A formation that may be capable of development into a mine, but which is untested. See also: favorable locality k. A sample of gold obtained in panning. Nelson l. A specimen or sample of mineral obtained from a small amount of paydirt or ore. Craigie m. To work (a mine, ledge, etc.) experimentally in order to ascertain its richness in precious minerals. Craigie prospect drilling The exploratory drilling of boreholes in the search for minerals and petroleum. Long prospect drill panner In metal mining, a person who, with a cable drill rig, drills down through gravel to bedrock along a present or an old creek bed that usually has been prospected by a handdug hole. The panner saves the drillings and pans them to discover the possible presence of paydirt (gold-bearing gravel), and weighs gold particles recovered. In the event of the discovery of gold in quantities sufficient for profitable removal, the panner moves drill and continues operations to determine the boundaries of the gold-bearing strata. DOT prospect entry See: prospect tunnel prospecting a. The search for outcrops or surface exposure of mineral deposits. b. Searching for new deposits; also, preliminary explorations to test the value of lodes or placers already known to exist. c. The surface discovery of coal or mineral only proves its superficial existence and further work is necessary to establish its quality and extent. The term exploration is sometimes applied to this extension of the discovery work. See also: exploration prospecting and mining Generic terms which include the whole mode of obtaining metals and minerals. Ricketts prospecting claim Aust. A claim larger than the average; allotted to the miner who is the first in a district to discover the presence of gold. Standard, 2 prospecting dish 2478

A simple appliance used in the search for gold and other heavy minerals. By means of water washing, the lighter, worthless material is separated from the valuable, heavier minerals, which are made visible by concentration and retention in the dish. Standard dishes with sloping sides are made in sizes ranging from top diameter 10 to 18 in (25 to 46 cm) and from 2 to 4 in (5 to 10 cm) deep, with riffles or grooves to retain the heavy minerals. Syn: pan prospecting license Authorization granted by a government to an individual in some countries, permitting the person to prospect for minerals and to register (stake) a claim. Pryor, 3 prospecting pan See: pan prospective ore Ore that cannot be included as proved or probable, nor definitely known or stated in terms of tonnage. See also: possible ore; ore expectant. prospector A person engaged in exploring for valuable minerals or in testing supposed discoveries of the same. prospect shaft A shaft sunk in connection with prospecting operations. Craigie prospect tunnel A tunnel or entry driven through barren measures, or a fault, to ascertain the character of strata beyond. Syn: prospect entry prospectus A preliminary printed statement describing a business or other enterprise, and distributed to prospective buyers, investors, or participants, giving detailed information concerning the company's business and financial standing. Common in mining. protecting magnet Electromagnet or permanent magnet installed ahead of crushing machinery to remove tramp iron that otherwise might enter and damage the appliances. Pryor, 3 2479

protection screen deck A screen plate with large apertures mounted over the screening deck in order to reduce the load and wear thereon. BS, 5 protective alkali In the cyanide process, the use of dissolved lime to maintain a slightly alkaline pulp, therefore ensuring that the cyanide salt retains its potency and does not acidify to hydrocyanic acid, which cannot dissolve gold or silver. See also: cyanide process protective alkalinity Lime added to auriferous pulp to ensure alkalinity. Important in the cyanidation process for precious metals. Pryor, 1 protest An objection to the patent proceeding; when made, it calls for a hearing on the matter in the local land office. Lewis protoamphibole A name for a series of artificial orthorhombic fluoramphiboles having only half the adimension of anthophyllite. The presence of lithium and absence of calcium appear to be essential to their formation. Named because of a structural relation to protoenstatite. Hey, 2 protoclase Leith's term for a rock possessing what he considered to be primary cleavage; e.g., bedding planes in sedimentary rock, formed concurrently with the rock. CF: metaclase protoclastic a. Said of igneous rocks in which the earlier formed crystals have been broken or deformed because of differential flow of the magma before complete solidification. AGI b. Said of an igneous rock containing deformed xenocrysts. AGI c. Said of the texture characteristic of an early stage of cataclasis, with a very small amount of finite strain. AGI protodolomite

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a. Dolomite with calcium and magnesium disordered within layers rather than ordered by layer. b. An imperfectly crystallized synthetic material of composition near CaMg(CO3 )2 . protogene See: protogine protogenous Said of original rocks as opposed to derived rocks, and including saline deposits, coal, igneous rocks, and ore deposits. The term is no longer used. Holmes, 2 protogine A granitic rock, occurring in the Alps, that has gneissic structure, contains sericite, chlorite, epidote, and garnet, and shows evidence of a composite origin or of crystallization (or partial recrystallization) under stress after consolidation. Also spelled protogene. The term, dating from 1806, is obsolete. AGI protomylonite a. A mylonitic rock produced from contact-metamorphosed rock, with granulation and flowage being due to overthrusts following the contact surfaces between intrusion and country rock. AGI b. A coherent crush breccia whose characteristically lenticular, megascopic particles faintly retain primary structures. It is a lower grade in the development of mylonite and ultramylonite. CF: ultramylonite proton An elementary particle with a single positive electrical charge and a mass approx. 1,847 times that of an electron. The atomic number of an atom equals the number of protons in its nucleus. Lyman protoquartzite A well-sorted, quartz-enriched sandstone that lacks the well-rounded grains of an orthoquartzite; specif. a lithic sandstone intermediate in composition between subgraywacke and orthoquartzite. AGI protore In older writings, any primary mineralized material too low in tenor to constitute ore but from which ore may be formed through secondary enrichment. As commonly employed today, the rock below the sulfide zone of supergene enrichment; the primary material 2481

that cannot be produced at a profit under existing conditions but that may become profitable with technological advances or price increases. See also: oxidized zone; sulfide zone. protractor An instrument used in drawing and plotting, designed for laying out or measuring angles on a flat or curved surface, and consisting of a plate marked with units of circular measure. See also: goniometer proustite A trigonal mineral, Ag3 AsS3 ; dimorphous with xanthoconite; rhombohedral cleavage; soft; ruby red; occurs in low-temperature or secondary-enrichment veins; a minor source of silver. Syn: light ruby silver; light red silver ore. prove a. To determine, by boring from the surface or driving a passageway underground, the location and character of a coalbed or the nature of rock strata. Hudson b. To establish, by drilling, trenching, underground openings, or other means, that a given deposit of a valuable substance exists, and that its grade and dimensions equal or exceed some specified amounts. See also: proved reserve proved ore See: proved reserve proved reserve An ore deposit that has been reliably established as to its volume, tonnage, and quality by approved sampling, valuing, and testing methods supervised by a suitably qualified person. The proved reserve is the overridingly important asset of a mine, and by its nature is a wasting one from the start of exploitation unless it is increased by further development. Syn: proved ore provenance A place of origin; specif. the area from which the constituent materials of a sedimentary rock or facies are derived. Also, the rocks of which this area is composed. CF: distributive province AGI prove up

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a. To show that the requirements for receiving a patent for government land have been satisfied. Webster 3rd b. Can. To establish economic value of a property. Hoffman proving hole a. A borehole drilled for prospecting purposes. b. Advance bore or heading into a mineral deposit, made either to check the quality of the ore being approached or to relocate a deposit that has been distorted or dislocated by faulting. Pryor, 3 proving ring A steel ring that has been accurately turned, heat treated, and polished. It is precisely calibrated in a testing machine by measuring its deflection for different loads and can be used for measuring applied loads on a structure. Hammond proving the area The establishment of the quantity and grade of coal or ore available for working by means of geological surveys, exploratory drilling, or exploring headings. Nelson proximate analysis a. The determination of the compounds contained in a mixture as distinguished from ultimate analysis, which is the determination of the elements contained in a compound. Used in the analysis of coal. Standard, 2; Fay b. The determination, by prescribed methods, of moisture, volatile matter, fixed carbon (by difference), and ash. The term proximate analysis does not include determinations of chemical elements or determinations other than those named. See also: chemical constitution of coal proximity log A Schlumberger log based on the principle of shallow investigation; as its name implies it is markedly affected by material that lies in its immediate proximity. It depends for its operation on the forcing of a more or less horizontal beam of current into the formation. Its vertical resolution is about 6 in (15 cm) and it is almost impervious to the presence of a mud cake on the formation wall. Wyllie prudent-man (person) test The basic legal standard for discovery under the mining law that states: Where minerals have been found and the evidence is of such a character that a person of ordinary prudence would be justified in the further expenditure of his labor and means, with a reasonable prospect of success in developing a valuable mine, the requirements of the statute have been met. SME, 1 2483

P.R.U. hand pump and densitometer A dust sampling instrument comprising a D.V.P. Mark 11 pump with a swept volume of 90 cm3 . A filter paper is inserted into a bridge behind the inlet nozzle of the pump such that a circle of 1-cm diameter of the filter paper is exposed to the dust. The dust, while passing through the filter paper, produces a stain. The optical density of the stain is determined photoelectrically in a densitometer by the light that falls upon a galvanometer. The dust particle concentration is evaluated by a calibration factor. Its main disadvantage is that it underestimates the number of fine particles. Nelson Prussian blue See: vivianite prussic acid See: hydrocyanic acid pry Eng. Cornish miners' term for soft white clay. Also spelled pryan. pryany lode A lode in which the ore is mixed with gossan or flucan. Arkell prypole A pole that forms the prop of a hoisting gin and stands facing the windlass. Webster 3rd psammite a. A sandstone. The term is equivalent to the Latin-derived term arenite. AGI b. A term formerly used in Europe for a fine-grained, fissile, clayey sandstone. AGI c. The metamorphic derivative of arenite. Etymol: Greek psammos, sand. See also: psephite; pelite. Adj. psammitic. AGI psatyrite See: hartite psephite a. A sediment or sedimentary rock composed of large fragments set in a matrix varying in kind and amount; e.g., talus, breccia, shingle, gravel, and esp. conglomerate. The term 2484

is equivalent to the Latin-derived term rudite. AGI b. The metamorphic derivative of rudite. Etymol: Greek psephos, pebble. See also: psammite; pelite. Adj: psephitic. AGI pseudoA prefix meaning false or spurious. AGI pseudoanticline An upward buckling of the superficial layers of the ground due either to changes in volume brought about by pedogenic processes or to some other nontectonic cause. Challinor pseudoboleite A tetragonal mineral, Pb5 Cu4 Cl10 (OH)8 .2H2 O ; indigo blue; occurs only in parallel growth on boleite, at Boleo, Baja California, Mex. Also spelled pseudoboleite. pseudobreccia A partially dolomitized limestone, characterized by: a mottled appearance, that gives the rock a texture mimicking that of a breccia; or by a weathered surface that appears fragmental. It is produced diagenetically by selective grain growth in which localized, patchy, and irregularly shaped recrystallized masses of coarse calcite are embedded in a lighter colored and less altered matrix of calcareous mud. AGI pseudobrookite An orthorhombic mineral, Fe2 (Ti,Fe)O5 ; resembles brookite; occurs in cavities in andesites. See: brookite pseudochromatism Colors and color plays produced by physical optics as opposed to chromophores; e.g., diffraction, dispersion, and scattering. Syn: structural color pseudoconglomerate A rock that resembles, or may easily be mistaken for, a normal sedimentary conglomerate. Examples include a crush conglomerate consisting of cemented fragments that have been rolled and rounded nearly in place by orogenic forces; a pebble dike; a sandstone packed with rounded concretions; and an aggregate of rounded boulders produced in place by spheroidal weathering and surrounded by clayey material. See also: crush conglomerate AGI 2485

pseudocrocidolite Quartz pseudomorphous after crocidolite. Syn: tiger's-eye; hawk's-eye. English pseudocrystalline Composed of detrital crystalline grains little worn and solidly compacted by siliceous or other mineral matrix, so as to resemble a true crystalline rock. pseudoeutectic texture Intergrowth of sulfide minerals that simulate eutectic texture in metals. See also: graphic granite pseudofibrous peat Peat that in spite of its fibrous condition, is soft, noncoherent, plastic, and on drying, shows great shrinkage. See also: fibrous peat; amorphous peat. Tomkeieff pseudogalena See: sphalerite pseudohexagonal Descriptive of minerals with hexagonal habit without hexagonal symmetry; e.g., hexagonal plates of monoclinic mica. pseudojade A name that may be applied to any mineral resembling jade in appearance; e.g., bowenite, massive serpentine. English pseudoleucite Large isometric crystals consisting of mixtures of nepheline and orthoclase, or of analcime formed as breakdown products of leucite; occurs in syenites from Arkansas, Montana, and Brazil. CF: leucite; metaleucite. pseudomalachite A monoclinic mineral, Cu5 (PO4 )2 (OH)4 ; trimorphous with ludjibaite and reichenbachite; dark green. Syn: dihydrite; phosphochalcite; phosphorochalcite; tagilite. pseudomorph 2486

A mineral sample with the external crystal form of one mineral and the internal chemistry of another; e.g., cubes of geothite after pyrite resulting from oxidation of the ferrous sulfide to ferric oxyhydroxide. CF: paramorph pseudomorphous quartz Quartz displaying the form and habit of any of several mineral species, which it has assumed through replacement. The most common quartz pseudomorphs are those of calcite, barite, fluorite, and siderite. Silicified wood is quartz pseudomorphous after wood. pseudomorphous tonstein A type of tonstein characterized by numerous pseudomorphs of kaolinite-feldspar or kaolinite-mica within a kaolinite groundmass. IHCP pseudophenocryst See: porphyroblast pseudophite A compact massive mixture of chlorite minerals resembling serpentine. pseudoporphyritic a. Said of the texture of an igneous rock in which larger crystals have developed in a macrocrystalline groundmass, but were formed, at least in part, after the rock solidified (e.g., large potassium-feldspar crystals in a granite). AGI b. See: porphyroblastic pseudosecondary inclusion A fluid inclusion formed by healing of a fracture occurring during growth of the host crystal. AGI pseudosuccinite Variety of amber differing from Baltic amber in its reaction to solvents. Tomkeieff pseudosymmetrical Said of crystal structures in which the atoms are only slightly displaced from positions that would be in accord with a higher symmetry. Thus, a monoclinic, pseudotetragonal mineral contains atoms only slightly displaced from positions of tetragonal symmetry. Hess 2487

pseudosymmetry a. Close angular approximation of a mineral with lower symmetry to one of higher symmetry; e.g., pseudohexagonal micas with monoclinic symmetry. b. Compound twins simulating an external symmetry not found in their atomic structure; e.g., orthorhombic aragonite in pseudohexagonal prisms. Syn: mimetic c. Abnormal crystal growth along one direction; e.g., elongate native gold cubes with apparent tetragonal symmetry. pseudotachylyte a. A dense rock produced in the compression and shear associated with intense fault movements, involving extreme mylonitization and/or partial melting. Similar rocks, such as some of the Sudbury breccias, contain shock-metamorphic effects and may be injection breccias emplaced in fractures formed during meteoric impact. CF: ultramylonite b. A dark gray or black rock that externally resembles tachylyte and that typically occurs in irregularly branching veins. The material carries fragmental clasts of adjacent rock units, and shows evidence of having been at high temperature. Miarolitic and spherulitic crystallization has sometimes taken place in the extremely dense devitrified base. Some pseudotachylyte has behaved like an intrusive and has no structures obviously related to local crushing. AGI pseudotopaz Quartz simulating topaz. From Striegau, Silesia, Poland. English pseudoviscosity Viscous resistance offered by a slurry, sludge, mud, or suspension of minerals in water as a pulp, due to the specific surface involved, with possibly an element of thixotropy under stated conditions of pH value, agitation, flow, temperature, and solid-to-liquid ratio. The pseudoviscous effect is distinct from viscosity due to molecular shear. Pryor, 3 pseudovolcano A large crater or circular hollow believed not to be associated with volcanic activity; e.g., a crater that is possibly meteoritic in origin but may be the result of phreatic explosion or cauldron subsidence. Adj: pseudovolcanic. AGI pseudowollastonite Synthetic triclinic CaSiO3 polymorphous with wollastonite-1T, wollastonite-2M, and wollastonite-7T. psilomelane 2488

a. A general term for massive oxides of manganese not otherwise identified; commonly botryoidal or colloform; a source of manganese in the United States (Arkansas, Virginia, Georgia); also in India, South Africa, and Russia. CF: cryptomelane; wad. b. See: romanechite; manganese oxide. CF: pyrolusite psilomelanite See: psilomelane psychrometer An instrument for measuring the vapor pressure and the relative humidity of the air or the quantity of moisture in the air. It consists of a dry-bulb thermometer and a wet-bulb thermometer, the latter having its bulb covered with a layer of muslin kept moist with water. The rate of evaporation from the moist muslin depends upon the quantity of moisture in the air. The more rapid the evaporation, the greater the cooling, and hence the greater the difference in the temperature readings of the two thermometers. Also called: hygrometer. Standard, 2 psychrometry a. Study of atmospheric humidity and its effect on workers. The psychrometer, or hygrometer, measures the difference between dry-bulb and wet-bulb thermometer readings. Pryor, 3 b. The determination of the psychrometric properties of air at a given state point. Hartman, 2 c. Measurement of the humidity of air. Nelson pteropod ooze A fine-grained pelagic deposit with more than 30% calcium carbonate of organic origin, of which pteropods are an important constituent. AGI ptilolite See: mordenite ptygmatic See: ptygmatic folding ptygmatic folding Primary folding in migmatites (injection gneisses, etc.), caused by the high-temperature and high-pressure processes to which the migmatites owe their origin and composite character. CF: flow folding 2489

public domain Land owned, controlled, or heretofore disposed of by the U.S. Government. It includes the land that was ceded to the Government by the original 13 States, together with certain subsequent additions acquired by cession, treaty, and purchase. At its greatest extent, the public domain occupied more than 1,820 million acres (737 million ha). See also: public land AGI public land Land owned by a government, esp. a national government; specif. the part of the U.S. public domain to which title is still vested in the Federal Government and that is subject to appropriation, sale, or disposal under the general laws. AGI public land and public use There is a clear distinction between public lands and lands that have been severed from the public domain and reserved from sale or other disposition under general laws. Such reservation severs the land from the mass of the public domain and appropriates it to a public use. Ricketts public limited liability company An association of individuals, at least seven in number, who together subscribe the necessary means or capital--i.e., money, property, or other credit--to engage in a joint undertaking. Truscott public mineral land Land belonging to the United States containing a deposit of mineral in some form, metalliferous or nonmetalliferous, in quantity and quality sufficient to justify expenditures in the effort to extract it and subject to occupation and purchase under the mining laws. Ricketts pucherite An orthorhombic mineral, BiVO4 ; trimorphous with clinobisvanite and dreyerite; reddish brown; a source of vanadium. pucking cutter A worker employed in a coal mine to cut the floor in cases of creep or upheaval toward the roof. CTD puddingstone 2490

a. A siliceous rock cut into blocks for furnace linings. b. See: conglomerate puddle a. Earthy material--such as a mixture of clay, sand, and gravel--placed with water to form a compact mass to reduce percolation. Seelye, 1 b. To place such material. Seelye, 1 c. To compact loose soil by soaking it and allowing it to dry. Nichols, 1 d. The molten portion of a weld. Webster 3rd e. To work (metal) while molten. Webster 3rd f. To subject (iron) to the process of puddling. Webster 3rd puddled steel Steel made in a puddling furnace, a type of reverberatory furnace in which the flame plays down upon the metal. Camm puddler a. Worker who converts cast iron into wrought iron by puddling. See also: puddling b. A rabble used in puddling. Webster 3rd c. A puddling furnace. Webster 3rd d. A system of small pipes admitting compressed air to a tank of water and zinc chloride, to effect a thorough solution for use as a timber preservative. Webster 2nd e. A machine for breaking up alluvial wash, consisting of a shallow tank in which the arms rotate slowly. The coarse stones are forked out and the pulp passed down sluice boxes along which the gold settles. See also: tormentor puddle roll Any of the roughing rolls through which puddle balls are passed to be converted into bars. Collectively called a puddle train. Standard, 2; Fay puddling The agitation of a bath of molten pig iron by hand or by mechanical means, in an oxidizing atmosphere, in order to oxidize most of the carbon, silicon, and manganese, and thus produce wrought iron. See also: danks' puddler puddling furnace A reverberatory furnace for puddling pig iron. Standard, 2 puddling machine A machine used for mixing auriferous clays with water to the proper consistency for the separation of the ore. Fay 2491

puddling process Production of wrought iron from molten pig iron, in an oxidizing atmosphere in a reverberatory furnace of special design. Pryor, 3 puff blowing Blowing chips out of a hole by means of exhaust air from the drill. (Nichols, 1976) puffed bar In powder metallurgy, a cored bar expanded by internal gas pressure. Rolfe puffer boy A person employed to operate an engine used for hauling loaded mine cars through haulageways. Also the operator of any small stationary hoisting engine. See also: puffer man puffer man In bituminous coal mining, a worker who operates a small hoisting engine used for hauling loaded mine cars through haulageways in a mine, or operates a small stationary engine used for hoisting coal or rock in a shallow shaft, esp. for prospecting or development work. Also called: puffer; puffer boy; puffer tender. DOT puffer tender See: puffer man puffstone Eng. Travertine; hard enough to use for building; so called from its cavernous structure. Arkell pug a. A parting of clay that sometimes occurs between the walls of a vein and the country rock; gouge. b. The coal left on the floor by a coal cutter. See also: following dirt c. Clay or other material used in packing cracks to prevent leakage; also, to use this material. d. Crushed strata or clay. See also: flucan pug lifter One who removes coal left adhering to the floor by a coal-cutting machine. CTD 2492

pug lifting The breaking and clearing of the coal left adhering to the floor by a longwall coal cutter. Nelson pug mill a. A machine for mixing water and clay, consisting of a long horizontal barrel containing a long longitudinal shaft fitted with knives; the knives slice through the clay, mixing it with water, which is added by sprays from the top. The knives are canted to give some screw action, forcing the clay along the barrel and out one end. AISI b. See: paddle-type mixing conveyor pug-mill operator a. One who prepares ground, sifted, and filtered clay for molding by mixing it with water in a rotary-type mixer called a pug mill. This machine is frequently operated in conjunction with an auger mill and a cutting machine, the same worker tending the operation of all three machines simultaneously. Also called clay pugger; mixing-mill operator. DOT b. One who mixes ground preheated magnesia and carbon with hot asphalt in a pug mill to form a viscous mixture suitable for processing into pellets. Also called: mixer tender; pug miller; pug-mill tender. DOT pug tub See: settler pull a. The unit advance during the firing of each complete round of shotholes in a tunnel. b. To loosen the rock around the bottom of a hole by blasting. Usually used with a negative to describe a blast that did not shatter rock to the desired depth. Nichols, 1 c. The amount of core obtained each time a core barrel is removed from a borehole. Long d. To draw or remove coal pillars, or pillars of ore. e. To hoist drill-stem equipment from a borehole. Long f. Strata movements over large excavated areas will extend to the surface and the disturbed surface area is almost always larger than the area of the underground excavation. The extent of this pull or draw depends on the depth of the workings, the nature of the strata, the thickness of the seam being mined, and the degree of packing support. See also: draw Lewis pull-apart structure Features produced in beds that have been disrupted and separated during soft-sediment deformation. See also: boudinage 2493

pull drift A small crosscut through barren ground to connect two orebodies. Hess puller-out An operator who charges, pulls out, and otherwise manipulates crucibles. Mersereau, 2 puller rod The rod used between the crank arm or drive arm of the drive unit and the panline of a shaker conveyor. Also called: connecting rod. Jones, 1 pulley a. A cylinder, with a shaft for mounting it so that it may rotate; used to change the direction or plane of belt travel. If the shaft is designed to be mounted so that it will not rotate, a pulley includes the bearings that provide for rotation of the cylinder on the shaft. NEMA, 2 b. A sheave or wheel with a grooved rim, over which a winding rope passes at the top of a headframe. Fay c. A wheel that carries a cable or belt on part of its surface. Nichols, 1 pulley man See: rollerman pulley oiler In bituminous coal mining, a laborer who oils and greases the pulleys on which run the cables that are used to raise and lower cars along haulage roads underground and at the surface of mines. DOT pulley repairman See: rollerman pull hole In sublevel stoping, term applied to a raise along the haulage level put up to the first sublevel. The raise is enlarged at the bottom into a grizzly chamber immediately over the haulage level and at the top is widened into a funnel-shaped opening. As ore is broken, it drops directly into a pull hole. Lewis pulling pillars 2494

The common expression used for mining the coal in the pillars of a mine; robbing pillars. See also: pulling stumps pulling stumps The process of taking out the pillars of a coal mine. See also: pulling pillars pull-over mill A two-high mill in which a piece is rolled in one direction only, and after traveling between the rolls has to be passed back over the top roll for rerolling. Osborne pull pin A device for throwing mechanical parts in or out of gear, or for readily shifting in or away from a fixed relative position. Crispin pull rope The rope that pulls a journey of loaded cars on a haulage plane; the rope that pulls the loaded scoop or bucket in a scraper loader layout. See also: tail rope pull shovel A shovel with a hinge- and stick-mounted bucket that digs while being pulled inward. Nichols, 1 pullway The path from the face to the loading point taken by the scraper of a scraper loading unit. Jones, 1 pull wheel A large driving wheel or sprocket. Nichols, 2 pulmonary dust Dust harmful to the respiratory system, including: silica (quartz, chert); silicates (asbestos, talc, mica, sillimanite); metal fumes (nearly all); beryllium ore; tin ore; iron ores (some); carborundum; coal (anthracite, bituminous). Syn: fibrogenic dust pulp

2495

a. A mixture of ground ore and water capable of flowing through suitably graded channels as a fluid. Its dilution or consistency is specified either as solid-liquid ratio (by weight) or as a percentage of solids (by weight). Pryor, 2 b. Pac. Pulverized ore or coal mixed with water; also applied to dry, crushed ore. See also: vacuum filter pulp assay Pac. The assay of samples taken from the pulp after or during crushing. pulp balance Balance that weighs ore or coal pulp in a container of known volume; graduated to show pulp density directly. Pryor, 3 pulp climate In mineral processing, the general physical and chemical conditions of a pulp, in which the pH, added chemicals, solid-liquid ratio, temperature, particle size range, and ionization of a flotation pulp are held within controlled limits while a considerable number of associated factors of less direct importance to the surface chemistry of the process are, at best, only indirectly monitored. Pryor, 3 pulp density a. In mineral processing, the amount of solids in a pulp, typically ranging from 10% to 25%, by weight. It has a marked effect on the recovery and grade of concentrate. Taggart, 1 b. The weight of a unit volume of pulp; e.g., if 1 cm3 of pulp weighs 2.4 g, then the pulp density is 2.4 g/cm3 . Newton, 1 pulp dilution The ratio of water to solids by weight. It is expressed as a ratio; e.g., a pulp dilution of 3 to 1 means that a pulp contains 3 t of water for each ton of solids. Newton, 1 pulpit The special platform upon which the operator of a Bessemer converter stands. Mersereau, 2 pulpit man Person who operates the complex controls of a rolling mill, in which iron and steel ingots or billets are rolled into shapes such as bars, T's, rails, and sheets, by throwing the correct electric switches when signaled or by personal observation. Also called: manipulator operator; mill control operator. DOT 2496

pulpstone A very large grindstone employed in pulp mills for crushing or grinding wood into fiber. Fay pulsator a. A motor-driven air compressor that supplies compressed air to an electric channeler. It receives the exhaust from the channeling machine cylinder and thus utilizes the pressure of the exhaust. b. In mineral processing, a Harz-type jig. See also: Harz jig Pryor, 3 pulsator jig A gravity concentrator utilizing vertical pulsations in a hydraulic medium to separate particles by specific gravity differences. pulsed infusion A variation of water infusion that has been effective in reducing both explosives consumption and airborne dust concentrations during mining. Water is introduced under pressure into long holes containing explosive charges and forced into the coal seam by detonation of the charges. See also: infusion shot firing pulsed infusion shot firing A coal blasting technique that consists of firing an explosive charge in a borehole filled with water under pressure. The water is introduced through an infusion tube that also seals the hole. When the charge is fired, it produces in the water a high-pressure impulse that is transmitted into the numerous water-filled cleavage planes and slips and thus breaks the coal. The energy from the explosive is used more efficiently than when blasting in the conventional manner, and better coal preparation is obtained. See also: water infusion; long-hole infusion. McAdam, 2 pulsion stroke In mineral concentration by jigging, the stroke of the plunger device that controls the hydraulic lift of water through the bed of particles. Pryor, 3 pulsometer a. A steam pump in which an automatic ball valve (the only moving part) admits steam alternately to a pair of chambers, forcing out water that had been sucked in by condensation of the steam after the previous stroke. It can tolerate very dirty water and has been widely used for shaft sinking and miscellaneous pumping duties. Nelson b. A displacement pump with valves for raising water by steam, partly by atmospheric 2497

pressure, and partly by the direct action of the steam on the water, without intervention of a piston. Also called: vacuum pump. Webster 3rd pulsometer pump Pump with two chambers that are alternately filled and discharged. An automatic ball valve admits steam, which forces out the charge from the filled chamber while the other is filling as its steam condenses. Pryor, 3 pulverization a. In soil stabilization work, the separation of particles from each other rather than the breaking up of individual particles. Separation of the particles is the first step towards good dispersion of stabilization additives and moisture. Nelson b. The reduction of metal to fine powder by mechanical means. Syn: comminution; soil stabilization. pulverize To reduce (as by crushing or grinding) to very small particles (as in fine powder or dust). Webster 3rd pulverized fuel Finely ground coal or other combustible material, that can be burned as it issues from a suitable nozzle, through which it is blown by compressed air. Pryor, 3 pulverizer See: fine grinder pulverulent That which may easily be reduced to powder. Said of certain ores. Weed, 2; Fay pumice A light-colored, vesicular, glassy rock commonly having the composition of rhyolite. It is often sufficiently buoyant to float on water and is economically useful as a lightweight aggregate and as an abrasive. The adjectival form, pumiceous, is usually applied to pyroclastic ejecta. CF: scoria; pumicite. AGI pumiceous Adj. form of pumice. 2498

pumicite A very finely divided volcanic ash or volcanic dust ranging in color from white to gray and buff. It is the unconsolidated equivalent of tuff. See also: ash pump A mechanical device for transferring either liquids or gases from one place to another, or for compressing or attenuating gases. AGI pump bob The balance weight used to bring up the plunger in a Cornish pumping engine. Standard, 2 pump chamber An underground pumping station. Fay pumpellyite a. A monoclinic mineral, Ca2 (Mg,Fe,Mn)(Al,Mn,Fe)2 (SiO4 )(Si2 O7 )(OH)2 .H2 O ; pumpellyite group; individual species named according to the preponderance of Fe, Mg, or Mn; occurs in minute bluish-green fibers or plates in Michigan, California, Haiti, and New Zealand. b. The mineral group jugoldite-(Fe), okhotskite, pumpellyite-(Fe), pumpellyite-(Mg), pumpellyite-(Mn), and shuiskite. Syn: Lake Superior greenstone Pumpelly's rule The generalization, made by Pumpelly in 1894, that the axes and axial surfaces of minor folds of an area are congruent with those of the major fold structures of the same phase of deformation. AGI pumper In bituminous coal mining, a person who works a hand pump to force water, accumulated underground in low places, into a drainage ditch flowing to a natural outlet or pumping station. See also: ram operator pump fist Eng. The lower end of a plunger case of a pump. pumping 2499

a. The act of moving a liquid or gas by means of a pump. b. The operation of filling a sludge pump by an up-and-down motion of the rods or rope. Also called pumping the sludger. c. In scraper operation, raising and lowering the bowl rapidly to force a larger load into it. Nichols, 2 d. Alternately raising and lowering a digging edge to increase the volume of dirt being transported. Nichols, 1 e. The motion of mercury in a barometer arising from the movement of a ship or from fluctuations of air pressure in a varying wind. CTD pumping engineer In mining and in the quarry industry, a person who operates one or a battery of pumps to force excess water from a lower level to the surface or to a drainage tunnel. Also called: pitwright; plugman. DOT pumping head In an airlift, the distance from the surface to the level of the water during pumping; it equals static head plus drop. Lewis pumping shaft The shaft containing the pumping machinery of a mine. Standard, 2 pump kettle A convex perforated diaphragm fixed at the bottom of a pump tube to prevent the entrance of foreign matter; a strainer. Fay pump lift a. The vertical distance that a pump can suck up water. Theoretically, this should be about 34 ft (10.4 m) at sea level; practically, the limit is about 26 ft (7.9 m). Long b. The vertical distance a pump can force water to flow. Long pump load The back pressure and/or resistance to flow of fluids that a pump must overcome to force a fluid to flow through a pipeline, drill string, etc. Long pump pressure The force per unit area or pressure against which a pump acts to force a fluid to flow through a pipeline, drill string, etc.; also, the pressure imposed on the fluid ejected from a pump. Long 2500

pump rod The rod or system of rods (usually heavy beams) connecting a steam engine at the surface or at a higher level with the pump piston below. See also: balance bob pump-rod plates Scot. Spear plates; strips or plates of iron bolted to wooden pump rods at the joints for the purpose of making the connection. Fay pump slip Leakage past the valves and the plunger in a reciprocating pump, which should not be greater than 2% or 3% for a pump in good condition. Lewis pump slope A slope in which pumps are operated. Fay pump station a. In mining, a chamber near the shaft at depth, where a pump is installed. Pryor, 3 b. An enlargement made in the shaft, slope, or entry to receive the pump. Also called pumproom. c. The site at which one or more pumps are installed along a pipeline for the purpose of forcing a fluid through the line. Long pump stock Lanc. See: pump tree pump sump A tank into which fluids gravitate and from which they are recirculated by means of a pump. BS, 5 pump surge The pulsating effect transmitted to a pipeline or drill string at the completion of each compression stroke of a reciprocating-piston pump. Long pump tree Eng. A cast-iron (wrought iron was formerly used) pipe, generally 9 ft (2.7 m) in length, of which the water column or set is formed. Syn: pump stock 2501

punch a. A tool (ram) for knocking out timbers in coal workings. Standard, 2 b. See: leg; punch prop. punched screen Thin plates through which holes have been punched. These may be round, rectangular, or slotted. Pryor, 3 puncher An early-model pick machine used to undermine or shear coal by heavy blows of sharp steel points attached to a piston driven by compressed air. Fay punching shear If a heavily loaded column punches a hole through the base on which it rests, the base has failed in punching shear. This is prevented either by thickening the base or by enlarging the foot of the column so as to ensure that the allowable shear stress is not exceeded. Hammond punch mining a. Mining in which the rooms are opened off the strip mine highwall. USBM, 3 b. An underground method of extracting coal from finger-shaped areas of reserves not amenable to other mining methods. Openings are driven by continuous mining machines back and forth across the fingers from outcrop to outcrop leaving a pillar of coal between each cut. punch prop A short timber prop for supporting coal in holing or undercutting; a sprag. Standard, 2 puppet valve A valve that, in opening, is lifted bodily from its seat by its spindle instead of being hinged at one side. See also: poppet; poppet valve. Fay puppy An underground set of pumps. Fay pure bending 2502

In mine subsidence, bending without fracture. Briggs pure coal See: vitrain pure culture A collection of microbial cells of the same species in a container that is devoid of any other form of life. Rogoff pure oxide Any of a group of refractories including alumina, magnesia, thoria, zirconia, beryllia, and ceria. Osborne pure oxide ceramic Ceramic product made from any of the pure oxides of nonmetallic materials; i.e., Al2 O3 , MgO, SiO2 , etc. pure shear A strain in which a rock body is elongated in one direction and shortened at right angles to this in such an amount that the volume remains unchanged. AGI pure steel The product of a basic open-hearth furnace refined to a point where the impurities are reduced to the lowest practicable minimum, after which copper and molybdenum are added in correct proportions. Mersereau, 2 purlins Timbers spanning from truss to truss, and supporting the rafters of a roof. Crispin puron High-purity iron. Osborne purple blende An old syn. for kermesite. Fay purple copper ore 2503

A miners' term for bornite. Syn: bornite purple ore Sintered pyritic ore. purpurite An orthorhombic mineral, MnPO4 ; forms a series with heterosite; deep red or reddish purple; forms small, irregular masses as an alteration product of lithiophilite and triphylite; at Pala, CA; Hill City, SD; Newry, ME; and the Erongo Mountains, Namibia. pushbutton coal mining A fully automatic and remotely controlled system of coal cutting, loading, and face conveying, including self-advancing roof support systems. See also: manless coal face pushbutton winding control A system in which the operation of the winder is similar to automatic cyclic winding, but the starting is instigated by the onsetter and banksman. When everything is ready for winding, the onsetter and banksman press their respective start pushbuttons and the winder starts, accelerates, and banks automatically without the intervention of the winding engineman. With this form of control, loading and discharging of the skips is fully automatic. See also: automatic cyclic winding; manual winding control. Nelson pusher a. A laborer who pushes loaded mine cars on tracks from underground working places to haulage roads where they are hooked up to a locomotive and hauled to the surface, shaft, or slope bottom for hoisting. A pusher may, at bituminous mines, shift empty and loaded cars in and about the tipple, where coal is prepared for market. Also called: car puller; car shifter; headsman; putter; trailer; trammer. Syn: mule; wheeler. DOT b. One who encourages or hastens the miners. Also called jigger boss. Ricketts c. A tractor that pushes a scraper to help it pick up a load. Nichols, 1 pusher tractor A bulldozer exerting pressure on the rear of a scraper loader while the loader is digging and loading unconsolidated ground being excavated and moved during opencast mining. push hole A hole through which glass is introduced to a flattening furnace. Standard, 2 2504

push-pull support system A method of advancing power-operated supports on a longwall face. Double-acting hydraulic jacks are used in conjunction with supports that slide forward on the floor and provide their own abutments for both their forward movement and that of the conveyor. Nelson push-pull wave A wave that advances by alternate compression and rarefaction of a medium, causing a particle in its path to move forward and backward along the direction of the wave's advance. In connection with waves in the Earth, also known as primary wave, compressional wave, longitudinal wave, or P-wave. Leet, 1 push wave See: P wave put To haul by hand. Mason putrefaction A process of decomposition of organic substances that occurs in the presence of water and with the complete exclusion of air. It is a kind of slow distillation whereby chiefly methane (CH4 ) and smaller quantities of other gaseous products, such as hydrogen (H2 ), ammonia (NH3 ), and hydrogen sulfide (H2 S), are formed. CF: disintegration PVC belt There are two main types of belts: (1) solid woven carcass impregnated and covered with polyvinyl chloride; and (2) normal multiple construction, which has polyvinyl chloride interlayers and covers. PVC belts are now used widely in coal mines, being not only fire resistant but equal, if not better, in quality than normal rubber belting. See also: conveyor Nelson P wave A seismic wave that propagates by alternating compressions and rarefactions in an elastic medium; the motion is in the direction of propagation. It is the type that carries sound. Syn: compressional wave; dilatational wave; irrotational wave; longitudinal wave; pressure wave; push wave. AGI pycnite 2505

A variety of topaz occurring in massive columnar aggregates. Also spelled pychite. pycnocline A steep vertical gradient of density. Hy pycnometer a. A device for weighing and thus determining the specific gravity of small quantities of oil or other liquids. Also spelled pyknometer. Hess b. A small bottle for determining the specific gravity of grains or small fragments. pyrabol See: pyribole pyralmandite A garnet composition between pyrope and almandine. See also: pyrope pyralspite The pyrope, almandine, spessartine subgroup of the garnet group. See also: pyrope pyramid An open crystal form consisting of nonparallel faces that intersect the c crystallographic axis and consist of three (trigonal), four (tetragonal), six (ditrigonal, hexagonal), or eight (ditetragonal) faces meeting at a point. CF: bipyramid; hemipyramid; dome. pyramidal Descriptive of a crystal habit dominated by pyramids or bipyramids. pyramidal garnet Same as idocrase; a variety of vesuvianite. Fay pyramid cut a. In tunnel driving or shaft sinking, a pattern of shotholes drilled so that the middle holes converge and outline a pyramid-shaped volume of rock. These holes are fired first, and thus create a free face or relieving cut. Pryor, 3 b. This cut has received its name from the shape of the initial opening. The three or four holes are so directed that they meet at a point farthest in. The pyramid cut is mainly employed in raises and for shaft 2506

sinking but is not recommended for horizontal tunnels where a machine setup for a definite direction of the four holes cannot easily be obtained. Syn: German cut c. This type of cut usually consists of four holes drilled to meet at a common apex in the center of the face. This arrangement permits a high concentration of explosive to be used, and the pyramid cut is therefore particularly suitable for breaking hard ground. In very hard ground the number of holes forming the cut may be increased to six. The main disadvantage of this type of cut is the difficulty in drilling the holes at the correct angles so that they will meet at the back of the cut. As in the case of the wedge cut, therefore, a hole director should be used. Also called diamond cut. McAdam, 2 d. In underground blasting, a type of cut employed in which the three cut holes in the center may be drilled to form a pyramid. Also applied to four holes meeting in a point. The simultaneous firing of these holes is somewhat equivalent to using a very heavy charge of explosive and makes a powerful blast. Lewis e. A cut in which four central holes are drilled towards a focal point, and when fired break out a tetrahedral section of strata. BS, 12 pyramid-set A bit crown, the face of which is covered with a series of stubby pyramids, each apex of which is set with a diamond. Long pyramid structure In crystallography, that of a crystal in which three or more inclined faces cut the three crystal axes. Pryor, 3 pyrargyrite A trigonal mineral, Ag3 SbS3 ; dimorphous with pyrostilpnite; rhombohedral cleavage; soft; deep red; in late-primary or secondary-enrichment veins, and an important source of silver. Syn: antimonial red silver; dark red silver ore; dark ruby silver. pyrene A tetracyclic hydrocarbon obtained from the coal-tar fraction boiling above 360 degrees C; C16 H10 ; soluble in carbon disulfide, toluene, and ligroin. CTD; Handbook of Chemistry and Physics, 2 pyreneite A black variety of andradite garnet. Syn: melanite pyrheliometer An actinometer that measures the intensity of direct solar radiation. AGI 2507

pyribole The pyroxene group plus amphibole group. See also: pyroxene pyricaustate A general name for a fossil combustible substance. Tomkeieff pyrite a. An isometric mineral, FeS2 ; dimorphous with marcasite; forms a series with cattierite; crystallizes in cubes and pyritohedra; sparks readily if struck by steel; metallic; pale bronze to brass yellow; hardness varies from 6.0 to 6.5; occurs in veins, as magmatic segregation, as accessory in igneous rocks, and in metamorphic rocks, in sedimentary rocks including coal seams; a source of sulfur; may have included gold. Syn: Alpine diamond; iron pyrite; fool's gold; mundic; common pyrite. b. The mineral group aurostibite, bravoite, cattierite, erlichmanite, fukuchilite, geversite, hauerite, insizwaite, krutaite, laurite, malanite, maslovite, michenerite, penroseite, pyrite, sperrylite, testibiopalladite, trogtalite, vaesite, and villamaninite. pyrites a. Various metallic-looking sulfide minerals including iron pyrites (pyrite); copper pyrites (chalcopyrite); tin pyrites (stannite); white iron, cockscomb, or spear pyrites (marcasite); arsenical pyrites (arsenopyrite); cobalt pyrites (linnaeite); magnetic pyrites (pyrrhotite); and capillary pyrites (millerite). Without qualification it popularly refers to pyrite. b. Stones that may be used for striking fire. pyrites of copper Common name for chalcopyrite. Weed, 1 pyritic Of, pertaining to, resembling, or having the properties of pyrites. Standard, 2 pyritic smelting Smelting of sulfide copper ores, in which heat is supplied mainly by oxidation of iron sulfide. Syn: oxidizing smelting pyritic sulfur The part of the sulfur in coal that is in the form of pyrites or marcasite. BS, 1 2508

pyritiferous Containing or producing pyrite. Webster 3rd pyritization Introduction of or replacement by pyrite; e.g., the replacement of original fossil material by pyrite. A common hydrothermal introduction of pyrite specks in rock adjacent to veins. pyritohedron An isometric closed crystal form of 12 faces, each an irregular pentagon. It is named after pyrite, which characteristically has this crystal form. See also: rhombic dodecahedron CF: dodecahedron pyroantimonite See: kermesite pyroaurite A trigonal mineral, Mg6 Fe2 (CO3 )(OH)16 .4H2 O ; hydrotalcite group; dimorphous with sjoegrenite; occurs in goldlike submetallic scales, or brown crystals having pearly to greasy luster. A silvery white variety is called igelstromite. pyrobelonite An orthorhombic mineral, PbMn(VO4 )(OH) ; descloizite group; forms minute fire-red acicular crystals at Laangban, Sweden; a source of vanadium. pyrobitumen Any of the dark-colored, fairly hard, nonvolatile, carbon-rich material substances composed of hydrocarbon complexes, which may or may not contain oxygenated substances and are often associated with mineral matter. The nonmineral constituents are infusible, insoluble in water, and relatively insoluble in carbon disulfide. AGI pyrobituminous Pertaining to substances that yield bitumens upon heating. AGI pyrochlore

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a. An isometric mineral, (Ca,Na)2 Nb2 O6 (OH,F) ; forms a series with microlite; in pegmatites in Maine, California, Colorado, Africa, and Europe; a source of niobium. Syn: pyrrhite b. The mineral group including the betafite subgroup betafite, plumbobetafite, and yttrobetafite; the microlite subgroup bariomicrolite, bismutomicrolite, microlite, plumbomicrolite, and uranmicrolite; and the pyrochlore subgroup bariopyrochlore, ceriopyrochlore, kalipyrochlore, plumbopyrochlore, uranpyrochlore, and yttropyrochlore. pyrochroite A trigonal mineral, Mn(OH)2 ; brucite group; soft; pearly white darkening on exposure; has perfect basal cleavage. pyroclast An individual particle ejected during a volcanic eruption. It is usually classified according to size. AGI pyroclastic Produced by explosive or aerial ejection of ash, fragments, and glassy material from a volcanic vent. Applied to the rocks and rock layers as well as to the textures so formed. Stokes pyroclastic deposit A deposit made up mainly of rock material that has been expelled aerially, normally explosively, from a volcanic vent, such as agglomerate, tuff, and ash. The fragments range in size from bombs and blocks to dust or ash. Such deposits are usually designated according to the lavas to which they correspond in composition. Stokes pyrogenesis A broad term encompassing the intrusion and extrusion of magma and its derivative. Adj. pyrogenic. AGI pyrogenetic A term introduced to designate minerals, such as olivine and chromite, developed at high temperature in melts containing only a small proportion of volatile (hyperfusible or fugitive) constituents. See also: pyrogenic pyrogenic

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Said of a process or of a deposit involving the intrusion and/or extrusion of magma. See also: pyrogenetic; igneous. AGI pyrogenic ore mineral An ore mineral that crystallized as a primary magmatic mineral of igneous rocks. Schieferdecker pyrogenic rock A rock resulting from the cooling of a molten magma; an igneous rock. pyrognostics The characteristics (such as the degree of fusibility or the flame coloration) of a mineral observed by the use of the blowpipe. Webster 3rd pyrolite An explosive resembling gunpowder in composition. Webster 2nd pyrolusite A tetragonal mineral, MnO2 ; rutile group; trimorphous with akhtenskite and ramsdellite; soft; metallic; steel gray; massive or reniform; a source of manganese. CF: psilomelane gray manganese ore. pyrolysis Chemical decomposition by the action of heat. pyrolytic graphite Graphite formed by pyrolysis of a carbonaceous gas. Van Vlack pyrometallurgy Metallurgy involved in winning and refining metals in which heat is used, as in roasting and smelting. Practically all iron and steel, nickel and tin, most copper, and a large proportion of zinc, gold, and silver, as well as many of the minor metals, are won from their ores and concentrates by pyrometallurgical methods. It is the most important and oldest class of the extractive processes. ASM, 1 pyrometamorphism 2511

Metamorphism produced by heat; it is a local, intense type of thermal metamorphism, resulting from unusually high temperatures at the contact of a rock with magma, such as in xenoliths. CF: igneous metamorphism; hydrometamorphism. See also: thermal metamorphism pyrometasomatic Formed by metasomatic changes in rocks, principally in limestone, at or near intrusive contacts, under the influence of magmatic emanations and high to moderate temperature and pressure. AGI pyrometasomatism Contact metamorphism. CF: metasomatism pyrometer An instrument that measures high temperature, e.g., of molten lavas, by electrical or optical means. See also: optical pyrometer pyrometric cone A small, slender three-sided pyramid made of ceramic or refractory material for use in determining the time-temperature effect of heating and in obtaining the pyrometric cone equivalent (PCE) of refractory material. Pyrometric cones are made in series, the temperature interval between successive cones usually being 20 degrees C. The best known series are Seger cones (Germany), Orton cones (United States), and Staffordshire cones (United Kingdom). See also: cone; orton cone. ARI; Dodd pyrometric cone equivalent The number of that standard pyrometric cone whose tip would touch the supporting plaque simultaneously with a cone of the refractory material being investigated when tested in accordance with ASTM Test Method C-24. Abbrev. PCE. ASTM pyromorphite A hexagonal mineral, Pb5 (PO4 )3 Cl ; apatite group, with iron replacing lead and arsenic replacing phosphorous; sp gr, 6 to 7; in oxidized zones of lead-ore deposits. Syn: green lead ore pyrope a. An isometric mineral, 8[Mg3 Al2 (SiO4 )3 ]; garnet group, with Fe and Mn replacing Mg and Cr replacing Al. See also: pyralspite; pyralmandite. Crystallizes in dodecahedra 2512

and trapezohedra; deep red to black; in high-pressure ultramafic and metamorphic rocks; also in placers; a gemstone and an abrasive. See also: Cape ruby; Bohemian garnet. Syn: rock ruby; magnesium-aluminum garnet. b. Formerly, a name for any bright red gem, such as ruby. pyrophane An opal, e.g., hydrophane, artificially impregnated with melted wax. See also: fire opal pyrophanite A trigonal mineral, MnTiO3 ; ilmenite group; forms a series with ilmenite; blood red. pyrophoric sphalerite A variety of sphalerite that gives off sparks or glows when abraded. Some pieces are so sensitive that the effect is obtained by scratching them with a fingernail. Hess pyrophyllite A monoclinic and triclinic mineral, Al2 Si4 O10 (OH)2 ; foliated; soft; in schists and hydrothermal veins in North Carolina, California, Newfoundland, and Japan. Syn: pencil stone. See also: G stone pyrophysalite A coarse opaque variety of topaz from Finbo, Sweden. Also spelled physalite. pyropissite An earthy nonphosphatic pyrobitumen composed primarily of water, humic acid, wax (a source of "montan wax"), and silica, associated with brown coal called pyropissitic brown coal. pyroradiation pyrometer A self-contained instrument with the millivoltmeter mounted in the pyrometer tube; the radiant energy is concentrated by means of an objective lens (quartz or fluorite) rather than by a reflecting mirror. Newton, 2 pyroretin A brittle, brownish-black resin that occurs in brown coal near Aussig, Bohemia; sp gr, 1.05 to 1.18. Fay 2513

pyrosmaltite Any member of the hexagonal mineral series, ferropyrosmaltite-manganpyrosmaltite, (Fe,Mn)8 Si6 O15 (OH,Cl)10 . pyrostibite See: kermesite pyrostibnite See: kermesite pyrostilpnite A monoclinic mineral, Ag3 SbS3 ; dimorphous with pyrargyrite; red. Syn: fireblende pyrosulfuric acid a. A heavy, oily, strongly corrosive liquid H2 S2 O7 that consists of a solution of sulfur trioxide in anhydrous sulfuric acid. It fumes in moist air and reacts violently with water with the evolution of heat. Webster 3rd b. A solution of sulfur trioxide in sulfuric acid; H2 S2 O7 . Colorless to dark brown depending on purity; hygroscopic. CCD, 2 pyroxene a. A group of chiefly magnesium-iron minerals including diopside, hedenbergite, augite, pigeonite, and many other rock-forming minerals. Although members of the group fall into different systems (orthorhombic, monoclinic, and triclinic), they are closely related in form, composition, and structure. See also: acmite; aegirite; augite; diallage; enstatite; hypersthene. Fay; AGI b. The mineral group aegirine (Ae), aegirine-augite, clinoenstatite, clinoferrosilite, diopside (Di), donpeacorite, enstatite (En), essenite (Es), ferrosilite (Fs), hedenbergite (Hd), jadeite (Jd), jervisite (Je), johannsenite (Jo), kanoite (Ka), kosmochlor (Ko), natalyite, omphacite, petedunnite (Pe), pigeonite, and spodumene (Sp). Some former names relegated to synonyms include acmite = aegirine, bronzite = enstatite, clinohypersthene = clinoenstatite or clinoferrosilite, diallage = altered diopside or other pyroxene with good (100) parting, eulite = ferrosilite, fassaite = ferrian aluminian diopside or augite, ferroaugite = augite, ferrosalite = hedenbergite, hiddenite = spodumene, hypersthene = enstatite or ferrosilite, kunzite = spodumene, salite = diopside, titanaugite = titanian augite, uralite = pseudomorphous amphibole after pyroxene, and ureyite = kosmochlor. Pyroxenes (px) are either monoclinic (clinopyroxenes, cpx) or orthorhombic (orthopyroxenes, opx). General formula: AB2 ZO6 : A = Ca, Fe2+ , Li, Mg, Mn2+ , Na, Zn; B = Al, Cr3+ , Fe2+ , Fe3+ , Mg, Mn2+ , Sc, Ti, V3+ ; Z = Al, Si. Their structures are built from single chains of silica tetrahedra each sharing two oxygens, with a silica:oxygen ratio of 1:3, electrostatic neutrality being maintained by cross-linking 2514

cations. Crystals are prismatic with prismatic cleavage at 87 degrees and 93 degrees . Colors are mostly greens, but range from white to black. Etymol: Greek pyros (fire) + xenos (stranger) from a mistaken belief that they were only accidently caught up in lavas. See also: aegirine pyroxene perthite Lamellar intergrowths of pyroxene of different kinds, as with the feldspars. Also pyroxene microperthite, pyroxene cryptoperthite. English pyroxenite A coarse-grained, holocrystalline igneous rock consisting of 90% pyroxenes. It may contain biotite, hornblende, or olivine as accessories. CTD pyroxenoid Single-chain silicates with individual silica tetrahedra twisted relative to the pyroxene chains, resulting in triclinic symmetry; e.g., the wollastonites, rhodonite, and pectolite. pyroxmangite A triclinic mineral, MnSiO3 ; forms a series with pyroxferroite where iron replaces manganese; forms brown cleavable masses near Iva, SC; Homedale, ID; Sweden; and Scotland. pyrrhite See: pyrochlore pyrrhoarsenite See: berzeliite pyrrhotine See: pyrrhotite pyrrhotite A monoclinic and hexagonal mineral, FeS ; invariably deficient in iron; variably ferrimagnetic; metallic; bronze yellow with iridescent tarnish; in mafic igneous rocks, contact metamorphic deposits, high-temperature veins, and granite pegmatites. Where associated with pentlandite and nickel replaces iron, it is a source of nickel. Also spelled pyrrhotine. Syn: magnetic pyrite; dipyrite. 2515

Q quad The composition quadrilateral for the Ca-Mg-Fe pyroxenes (enstatite-ferrosilite-diopsidehedenbergite). quadrantal bearing A horizontal angle or bearing less than 90 degrees , measured to north, south, east, or west from a survey line. Hammond quadrant cutter A machine that will make a shear cut as well as a horizontal cut. The central column is wedged tightly between roof and floor and operates similarly to a radial percussive coal cutter. Nelson quadrant search Similar to octant search, but using four sectors instead of eight sectors. Applies to any interpolation method where a limited number of sample data points are used to estimate intermediate values. quadrilateral A four-sided plane figure of any shape, having an area equal to the product of the diagonals multiplied by half the sine of the angle between them. Hammond quadrille twinning See: crossed twinning quadrivalent a. Having a valence of 4. Webster 3rd b. Having four valences; e.g., chlorine, which has a valence of 1, 3, 5, and 7. Handbook of Chemistry and Physics, 2 quadruple block A pair of blocks, each having four sheaves, reeved with rope or cable and used to increase the lifting capacity of a drill-hoisting mechanism; a four-sheave block and tackle. Long 2516

quagmire A soft marsh or bog that gives under pressure. CF: quaking bog. AGI quake sheet A well-defined bed resembling a slump sheet but produced by seismic shock from an earthquake and resulting in load casting without horizontal slip. AGI quaking bog A peat bog that is either floating or is growing over water-saturated ground, so that it shakes or trembles when walked on. Quagmire is sometimes used as a synonym. AGI qualitative analysis In chemistry, the process of determining which elements are present. Standard, 2 quality a. Refers to the nature, and not the amount, of material. In the case of a coal seam, its quality is closely linked with its rank and its chemical composition. In the case of metals, average unit values are determined by systematic sampling and therefore represent a known quantity. See also: ventilation standards b. Native values of a gem irrespective of color and cut. Hess c. The ratio by weight of vapor to liquid plus vapor in a mixture, as in steam. Strock, 2 quality control a. Systematic setting, check, and operation designed to maintain steady working conditions in continuous process such as mineral concentration; to forestall trouble; to check condition of ore, pulp, or products at important transfer points. Pryor, 3 b. Graphic method of exposing abnormalities in sets of figures produced by measurement of repetitive operations or as variances from operating norms. Pryor, 3 c. The maintaining of air within desired limits of purity. Hartman, 1 quantitation Once a dust sample has been collected, it must be evaluated. Of principal concern is quantitation--determining how much dust or how many particles. Certain methods of quantitation are favored for the various sampling methods. The number basis is preferable for evaluating a pulmonary hazard, while the weight basis is preferred for toxic, radioactive, or explosive hazards. Number quantitation is usually employed for impinger, konimeter, molecular filter, and thermal precipitator samples. Weight quantitation is used for filter paper and electrostatic samples. Hartman, 1 2517

quantitative In testing ore, how much of each metal is present. von Bernewitz quantitative analysis In chemistry, the process of determining the quantity of each element present. Also called elementary analysis. Both volumetric and gravimetric methods are included. Standard, 2 quantitative survey See: ventilation survey quantity Deals with the amount, and not the nature, of a substance. In the case of a coal seam, quantity refers to its workable thickness and acreage. In the case of ore, the quantity determines its commercial importance. Unit ore values without the quantity factor have only a qualitative significance. Nelson quantity control The control of air movement, its direction, and its magnitude. Hartman, 2 quantity-distance table A table listing minimum recommended distances from explosive material stores of various weights to a specific location. Meyer quaquaversal Dipping outward in all directions from a central point, as a dome in stratified rocks. CF: centroclinal; periclinal. quaquaversal fold See: dome quarey lode See: quarry lode quarfeloids A portmanteau word from quartz, feldspar, and feldspathoids. CF: feloids 2518

quarl A large brick or tile; esp., a curved firebrick used to support melting pots for zinc and retort covers. Webster 3rd quarman See: quarryman quarpit An obsolete term for a quarry. quarrel a. A stone quarry. Standard, 2 b. Materials from a quarry. Standard, 2 quarrier A worker in a stone quarry. Standard, 2 quarry a. An open or surface mineral working, usually for the extraction of building stone, as slate, limestone, etc. It is distinguished from a mine because a quarry usually is open at the top and front, and, in ordinary use of the term, by the character of the material extracted. See also: opencast b. Day work pit. Also called opencast; quarpit. Pryor, 3 c. An underground excavation formed in the roof, or fault, for the purpose of obtaining material for pack walls. quarry body A dump body with sloped sides. Nichols, 1 quarry drainage Arranging the quarry layout so that pools of water do not collect in the working area. One-half percent grade away from the face will generally keep the floor free of mud and water. Nelson quarry drill A blasthole drill. Nichols, 1 quarry face 2519

The freshly split face of ashlar, squared off for the joints only, as it comes from the quarry, and used esp. for massive work. Distinguished from rock face. Webster 3rd quarry-faced masonry Masonry in which the face of the stone is left unfinished just as it comes from the quarry. Crispin quarry floor The lowest level on which stone is loaded. Streefkerk quarrying a. The surface exploitation of stone or mineral deposits from the Earth's crust. Nelson b. Removal of rock that has value because of its physical characteristics. Nichols, 2 c. One of the effects of glaciation whereby blocks of stone, bounded mainly by joint planes, are lifted from the bedrock and carried away by ice. Also called plucking. Stokes quarrying machine Any machine used to drill holes or cut tunnels in native rock; a gang drill, or tunneling machine, but most commonly a small form of locomotive, bearing a rock-drilling mechanism, and operating on a track laid temporarily along or opposite the ledge to be cut. Standard, 2 quarry lode A vein in a heading that is jointed and blocky, like granite in a quarry, or a heading in granite. quarry machine See: quarrying machine quarryman a. A person employed at the face of a quarry, stripping, drilling, excavating, and loading rock or economic product. Nelson b. One who operates a jackhammer to drill holes in quarry stone, and drives wedges into the holes to break or split off slabs or blocks of stone. Also called hammerman; plug-and-feather driller; rockman; rock splitter. DOT c. In crushed rock quarries, a laborer who performs any one or combination of such duties as: loading rock into boxes to be hoisted out of quarry pit; assisting in moving power shovel from one loading position to another; dumping rock from cars into crusher or storage bins; feeding rock into a crusher; tending belt conveyors that transport crushed 2520

rock from crusher to storage bins; loading crushed rock from storage bins into trucks or railroad cars. DOT d. In building stone quarries, a laborer who performs any one or combination of such duties as: cleaning dirt and mud from surface and sides of stone deposits; chipping irregularities from surface of granite blocks; breaking large pieces of stone into smaller sizes suitable for building purposes with a sledge hammer; attaching hoisting cable hooks or slings to blocks of stone to be hoisted from quarry; guiding and steadying blocks of stone as they are loaded at the quarry surface on trucks or railraod cars by a derrick. DOT quarry powder Ammonium nitrate dynamites intended to replace the more costly gelatin dynamites used in quarrying, where blasts of several tons of explosives are used. Cartridges up to 8 in (20 cm) in diameter by 21 in (53 cm) in length, can be enclosed in metal cans to protect against water damage. Lewis quarry-rid Overburden. CF: ridding quarry sap a. The moisture contained in newly quarried stone. Arkell b. See: quarry water quarry waste Material discarded after crushing, as being too fine, irregular, or flaky for constructional work. Nelson quarry water a. Water that fills the pore spaces of a rock in a quarry. See also: ground water b. Subsurface water retained in freshly quarried rock. Syn: quarry sap. AGI quartation The separation of gold from silver by dissolving out the latter with nitric acid. It requires not less than three-fourths of silver in the alloy, whence the name, which is also applied to the alloying of gold with silver, if necessary, to prepare it for this method of parting. See: parting quarter

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a. The act or process of dividing sludge, core, and other pulverized or granular samples into four equal parts. See also: quartering. Long b. Syn. for quadrant as applied to a drillbit crown. Long quartering a. The reduction in quantity of a large sample of material by dividing a heap into four approx. equal parts by diameters at right angles, removing two diagonally opposite quarters and mixing the two remaining quarters intimately together so as to obtain a truly representative half of the original mass. The process is repeated until a sample is obtained of the requisite size. Syn: coning; coning and quartering. Taylor b. To split a piece of core longitudinally into four equal parts. Long quartering in Lanc. A plan of building or putting together tubbing plates from the top downward, the rings and segments being bolted together as the work of excavation proceeds. quartering way a. A quarry term to designate a direction in which a rock cleaves with moderate facility; grain. See also: roughway b. The direction of the natural joints in a quarry rock. CF: rift c. Grain, second way, bate, hem, sheeting plane. quarter line Western United States. The survey line by which a section of government land is divided into quarter sections. quarterly survey An underground survey required by law to be undertaken at least once every three months for the purpose of bringing the working plans and other plans up to date. BS, 7 quarter octagonal A square shaft with corners cut back. Nichols, 1 quarter-point veins Small veins having an intermediate bearing between strike and cross veins. quarter post

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A post marking a corner of a quarter section of the U.S. Public Land Survey system. It is located midway between section corners. AGI quarter section A fourth of a normal section of the U.S. Public Land Survey system, representing a piece of land normally 1/2 mile (0.8 km) square and containing 160 acres (64 ha) nearly as possible. It is usually identified as the northeast, northwest, southeast, or southwest quarter of a particular section. AGI quartz a. A trigonal mineral, SiO2 ; polymorphous with tridymite, cristobalite, coesite, tishovite, and keatite. Amethyst is a variety of the well-known amethystine color. Aventurine is a quartz spangled with scales of mica, hemitite, or other minerals. False topaz or citrine is a yellow quartz. Rock crystal is a watery clear variety. Rose quartz is a pink variety. Rutilated quartz contains needles of rutile. Smoky quartz is a brownish variety, sometimes called cairngorm. Tigereye is crocidolite (an asbestoslike mineral) replaced by quartz and iron oxide and having a chatoyant effect. The name of the mineral is prefixed to the names of many rocks that contain it, as quartz porphyry, quartz diorite. See also: alpha quartz; beta quartz; high quartz; low quartz. Sanford; Fay b. Pac. Any hard, gold or silver ore, as distinguished from gravel or earth. Hence, quartz mining, as distinguished from hydraulic mining, etc. Fay c. A general term for a variety of cryptocrystalline varieties of SiO2 ; e.g., agate, chalcedony. quartz andesite See: dacite quartz battery A stamp, or series of stamps, for crushing quartz ore. Mathews quartz boil An outcrop of a quartz vein. quartz claim In the United States, a mining claim containing ore in veins or lodes, as contrasted with placer claims carrying mineral, usually gold, in alluvium. quartz conglomerate A rock made of pebbles of quartz with sand. Osborne 2523

quartz diorite A group of plutonic rocks having the composition of diorite but with an appreciable amount of quartz, i.e., between 5% and 20% of the light-colored constituents; also, any rock in that group; the approximate intrusive equivalent of dacite. AGI quartz felsite See: quartz porphyry quartz glass Glass made by fusing quartz. quartz gold Gold that is not rounded and waterworn, but irregular and frequently twisted in form, usually very bright, and always of fine quality. Craigie quartzic See: quartziferous quartziferous Quartz-bearing as applied to a rock not defined by the presence of quartz, but containing minor amounts of it; e.g., limestone. Syn: quartzic. See also: quartzose quartz index a. A derived quantity (qz) in the Niggli system of rock classification, which may be either positive or negative, and is as indicator of a rock's degree of silica saturation. AGI b. A term used to indicate the mineralogic maturity of a sandstone by measuring the percentage of detrital quartz. It is expressed as the ratio of quartz and chert to the combined percentage of sodic and potassic feldspar, rock fragments, and clay matrix. The index is used as a basis for evaluating the degree of weathering of the source rock and the degree to which the sediment has been transported. Values for sandstones range between 3 and 19. AGI quartzite a. A granoblastic metamorphic rock consisting mainly of quartz and formed by recrystallization of sandstone or chert by either regional or thermal metamorphism; metaquartzite. CF: orthoquartzite b. A very hard but unmetamorphosed sandstone, consisting chiefly of quartz grains that are so completely cemented with secondary silica 2524

that the rock breaks across or through the grains rather than around them; an orthoquartzite. AGI c. Stone composed of silica grains so firmly cemented by silica that fracture occurs through the grains rather than around them. USBM, 7 d. As used in a general sense by drillers, a very hard, dense sandstone. Long e. A granulose metamorphic rock consisting essentially of quartz. Holmes, 1 f. Sandstone cemented by silica that has grown in optical continuity around each fragment. Syn: ganister quartzitic Of, pertaining to, or consisting of quartzite. quartz keratophyre Altered sodic diabase (trachyte) with accessory quartz. quartz latite The extrusive or hypabyssal equivalent of a quartz monzonite. The principal minerals are quartz, sanidine, biotite, sodic plagioclase, and hornblende, commonly as phenocrysts in a groundmass of potash feldspar and quartz (or tridymite, cristobalite), or glass in flows. Accessory minerals are magnetite, apatite, and zircon. quartz lead A lode or vein of ore with quartz gangue. quartz liquefier In metallurgy, an apparatus for extracting gold from its ore. By the action of an alkali and high-pressure steam, gold-bearing quartz is converted into a soluble silicate from which gold may be separated by washing. Standard, 2 quartz mill A machine or establishment for pulverizing quartz ore, in order that the gold or silver it contains may be separated by chemical means; a stamp mill. Standard, 2; Fay quartz mine a. A mine in which the deposits of ore are found in veins or fissures in the rocks forming the earth's crust. Usually applied to lode gold mines, but not to placers. b. A miner's term for a mine in which the valuable constituent, e.g. gold, is found in siliceous veins rather than in placers. It is so named because quartz is the chief accessory mineral. AGI quartz monzonite 2525

A medium- to coarse-grained plutonic rock containing major plagioclase, orthoclase, and quartz, with minor biotite, hornblende, and accessory apatite, zircon, and opaque oxides. Syn: adamellite quartzoid A crystal having the form of two six-sided pyramids base to base. Standard, 2 quartz ore A rock containing a large quantity of quartz. Gordon quartzose a. Of, pertaining to, or consisting of quartz. b. Containing quartz as a principal constituent; esp. applied to sediments and sedimentary rocks (e.g., sands and sandstones) consisting chiefly of quartz. CF: quartziferous quartzous See: quartzose quartz porphyry A field term for a medium-grained porphyritic igneous rock of felsic but unspecified composition occurring normally as minor stock or dike intrusions, and carrying prominent phenocrysts of quartz. It is a common altered companion to porphyry copper deposits. Syn: quartz felsite quartz reef A lode or vein of quartz. See also: reef quartz sinter Siliceous sinter. Fay quartz syenite A potash or soda syenite with quartz as an accessory, hence on the borderline between syenite and granite. quartz trachyte

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A fine-grained igneous rock consisting mostly of alkali feldspar, with normative quartz between 5% and 20%; the volcanic equivalent of quartz syenite. It normally shows trachytic texture. AGI quartz wedge a. An optical accessory with varying retardation used in polarized-light microscopy to determine birefringence and optic sign. CF: Berek compensator b. In polarized-light microscopy, an accessory plate that gives variable compensation for birefringence. CF: accessory plate; gypsum plate. quartzy See: quartzose Quaternary The second period of the Cenozoic era, following the Tertiary; also, the corresponding system of rocks. It began 2 to 3 million years ago and extends to the present. It consists of two grossly unequal epochs; the Pleistocene, up to about 10,000 years ago, and the Holocene since that time. The Quaternary was originally designated an era rather than a period, with the epochs considered to be periods, and it is still sometimes used as such in the geologic literature. The Quaternary may also be incorporated into the Neogene, when the Neogene is designated as a period of the Tertiary era. AGI quaternary alloy An alloy containing four principal elements. Rolfe queane See: quene quebracho Aqueous extract of a bark of quebracho tree; contains up to 65% tannin. Used in frothflotation as depressant for oxidized minerals. Pryor, 3 queen Slate measuring 36 in by 24 in (91.44 cm by 60.96 cm). Pryor, 3 queer

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A fissure, joint, or small cavity in a rock or quartz vein. Also spelled quere, queere, and qweear (U.K.). queery Corn. When the lode or rock on which the miner is driving partakes of the character of quarry stone, namely, in detached lumps by natural divisions, it is called queery ground, and is frequently worked with crowbars and levers instead of being blasted or gadded. A "queer of ground" is a detached rock. Also called quarry lode. See also: queer quench a. To cool suddenly (as heated steel) by immersion, esp. in water or oil. Webster 3rd b. To produce a crust or a succession of crusts on molten metal, each crust being removed as it is formed. Standard, 2 quenching Generally means rapidly cooling metals and alloys, or any substance to below the critical range by immersing it in oil or water to harden it. Also applied to cooling in salt and molten-metal baths or by means of an air blast, and to the rapid cooling of other alloys after solution treatment. CTD quenching oils Oils used in heat treating. Fish oils are often used. Minerals, fish, vegetable, and animal oils are often compounded and sold under trade names. Crispin quenching tub A tub of water in which to cool, harden, or temper iron or steel. Standard, 2 quene Crevice in lode or vein. Also spelled queane. Hess quenselite A monoclinic mineral, PbMnO2 (OH); occurs in pitch-black crystals with perfect cleavage; at Laangban, Sweden. Querwellen wave See: Love wave 2528

questal bentonite A colloidal bond which, when added to molding sands in amounts up to 3%, increases porosity and strength (green and dry), and reduces the amount of water needed. Osborne quick a. Said of a sediment that, when mixed with water, becomes extremely soft and incoherent and is capable of flowing easily under load or by force of gravity; e.g. quick clay or quicksand. AGI b. Said of blasting powder that burns or goes off very rapidly. c. See: quicksilver d. Said of an economically valuable or productive mineral deposit, in contrast to a dead ground or area. An ore is said to be quickening as its mineral content increases. Syn: alive quickening Descriptive of an ore as its mineral content increases with distance. quicklime sizes The different sizes depending upon the type of limestone, kind of kiln used, or treatment subsequent to calcining. The sizes commonly recognized are as follows: (1) large lump-8 in (203 mm) and smaller; (2) pebble or crushed--2-1/2 in (64 mm) and smaller; (3) ground, screened, or granular--1/4 in (6.4 mm) and smaller; and (4) pulverized-substantially all passing a No. 20, 850 mu m, sieve. ASTM quickness The property of an explosive by virtue of which it exerts a sharp blow or shattering effect on the material with which it is in contact. The quickest explosive of the dynamite class is the 60% straight dynamite. Quick explosives are the ones particularly desired for mudcapping. For maximum effect for this purpose, they should be of high density and sensitiveness. See also: quick quicksand A mass or bed of fine sand, that consists of smooth rounded grains with little mutual adherence and that is usually saturated with water flowing upward through the voids, forming a semiliquid, highly mobile mass that yields easily to pressure. See also: running ground. Syn: running sand quicksilver A common name for mercury. Syn: native mercury 2529

quicksilver cradle A wooden box placed in a sloping position, and fixed upon rockers, in which goldbearing gravel is washed, the gold being caught by mercury in the lower part of the cradle. Fay quicksilver rock An altered rock consisting mainly of dark opal and chalcedony, commonly associated with ore in California mercury deposits in serpentine. quick test A shear test of a cohesive soil without allowing the sample to drain. See also: drained shear test Quigley gun An air gun which mixes dry, granular, refractory materials with water. quill shaft A light drive shaft inside a heavier one, and turning independently of it. Nichols, 1 quincite Light carmine-red particles found in a limestone near Quincy, France; color apparently organic; a doubtful mineral. Dana, 1 quinquevalent a. Having a valence of 5. Webster 3rd b. Having five valences. Tungsten has five valences which are 2, 3, 4, 5, and 6. Handbook of Chemistry and Physics, 2 quitclaim a. A release of a claim; a deed of release; specif., a legal instrument by which some right, title, interest, or claim by one person in or to an estate held by himself or another is released to another, and which is sometimes used as a simple but effective conveyance for making a grant of lands whether by way of release or as an original conveyance. Webster 3rd b. In the United States, a document in which a mining company sells its surface rights but retains its mineral rights. Nelson quoin 2530

a. The keystone or a voussoir of an arch. b. A wedge to support or steady a stone. c. A large square ashlar or stone at the angle of a wall to limit the rubble and make the corner true and strong; an exterior masonry corner. d. One of the four facets on the crown, pavilion, or base of a gem. Q wave See: Love wave

R rabatage A system of working steep seams of any thickness. Nelson rabbit-eye York. Limestone in the Coralline Oolite. CF: toad's-eye rabbittite A monoclinic mineral, Ca3 Mg3 (UO2 )2 (CO3 )6 (OH)4 .18H2 O ; radioactive; forms yellow efflorescence on mine walls. rabble a. An iron scraper serving as a rake in removing scoriae from the surface of melted metal. Fay b. A charcoal burner's shovel. Webster 3rd c. A mechanical rake for skimming the bath in a melting or refining furnace or for stirring the ore in a roasting furnace by hand or mechanically. Webster 3rd rabbler a. See: rabble b. One who uses a rabble, as in puddling iron. Standard, 2 c. A scraper. Standard, 2 rabbling Stirring molten metal, ore, or other charge, using a hoelike tool or other device. ASM, 1 rabbling tool A rabble of simple construction for use by hand. Also called rabble rake. See also: rabble 2531

race A small thread of spar or ore. raceway The term is applied to conduits, moldings, and other hollow material, often concealed, through which wires are fished from one outlet to another. Crispin rack a. An inclined trough for washing or separating ore. Nelson b. A toothed or notched drillbase-slide and meshing-gear pinion used to facilitate the moving of a drill to clear the borehole when hoisting or lowering the drill string; generally limited to larger, skidmounted machines. Long c. A framework of wood or metal for the orderly storage of core, pipe rods, etc., in a horizontal position. Long d. A tilting table on which concentrates are separated from the passing flow of finely ground pulp, the system being arranged to be periodically self-flushing. Pryor, 3 e. A screen composed of parallel bars to catch floating debris. Seelye, 1 f. In electroplating, a frame used for suspending and conducting current to one or more cathodes during electrodeposition. Lowenheim rack-a-rock Mining explosive based on a mixture of potassium chlorate and nitrobenzene. Pryor, 3 rack back To move a drilling machine away from the borehole collar by sliding it on its base, using the rack-and-gear pinion to facilitate moving the machine. See also: rack racked timbering Timbering braced diagonally as stiffening against deformation. Hammond rack frame Inclined table used to treat slimes. Pryor, 1 rack gear A toothed bar. Nichols, 1 racking

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a. Old term for concentration in sluice boxes. b. The process of separating ores by washing on an inclined plane. c. See: ragging racking table A table on which to wash ore slimes. See also: rack rack railroad A cog railway; cog tramway. Fay rack up a. To move the drilling machine forward into alignment with the borehole, using the rack-and-gear pinion to facilitate moving the machine. Long b. To stack and arrange the drill rods in an orderly fashion in the tripod, mast, or derrick, or horizontally on a rack provided on the ground. Long c. To place core on a rack. Long radial Said of lines or other linear phenomena converging at a single center or departing from one. radial arm The movable cantilever supporting the drilling saddle in a radial drilling machine. Crispin radial axis See: longitudinal trace radial dikes A descriptive term for dikes that radiate outward from a center, commonly a volcanic neck or stock. radial drainage pattern A drainage pattern in which consequent streams radiate or diverge outward, like the spokes of a wheel, from a high central area; it is best developed on the slopes of a young, unbreached domal structure or of a volcanic cone. AGI radial drill 2533

a. A heavy drilling machine in which the drilling head is capable of radial adjustment along a rigid horizontal arm carried by a stand. See also: radial percussive coal cutter b. A small diamond drill having a drilling head that can be adjusted radially along a rigid horizontal arm radiating from a vertical column; usually driven by air and used to drill radial blastholes underground. See also: radial drilling radial drilling The drilling of a number of holes in a single plane and radiating from a common point. CF: horadiam radial-flow fan A mine fan in which the air enters along the axis parallel to the shaft and is turned through a right angle by the blades and discharged radially. There are three main types with (1) backwardly inclined blades; (2) radial blades; and (3) forward curved blades. In (2) and (3) the blades are made of sheet steel, while in (1) the present tendency is to replace curved sheet-steel blades by blades of aerofoil cross section. The aerofoil bladed radial-flow fan has an efficiency of about 90%. CF: axial-flow fan; mixed-flow fan. Nelson radial machineman In bituminous coal mining, a person who operates a radial-type coal cutter. The machine remains stationary at the center of the working place and undercuts or shears the coal in an arc rather than making a straight cut by moving across the working face. Also called arcwall machineman. DOT radial percussive coal cutter A heavy coal cutter for use in headings and rooms in pillar methods of working. The machine weighs about 12 hundredweight (545 kg) and is usually mounted on a light carriage to suit the mine track. A percussive drill, with extension rods, makes a horizontal cut about 5-1/2 ft (1.68 m) deep and 15 ft (4.57 m) wide at any height in the heading. The central column is tightened between roof and floor about 4-1/2 ft (1.37 m) from the face. The machine can also be used for drilling shotfiring holes. Nelson radial pressure The radial pressure of wire rope is a function of the rope tension, rope diameter, and tread diameter. The radial pressure can be determined by the following equation: P = 2T/Dd, where P equals radial pressure in pounds per square inch; T equals rope tension in pounds; D equals tread diameter of sheave or drum in inches; and d equals rope diameter in inches. 2534

radial slicing A method of caving by which all the ground around a central raise might be worked in a series of slices arranged like the spokes of a wheel. Lewis radial strain The change in length per unit length in a direction radially outward from the charge. Duvall radial stress a. Stress normal to the tangent to the boundary of any opening. Obert b. In the Earth, the stress normal to a spherical surface. radial velocity In a fan, the quantity of air delivered in cubic meters per second divided by the outlet area of the fan at the periphery. radial ventilation A ventilation system in which a number of downcast shafts arranged around the periphery of the working area are served by a common upcast shaft within the area, or vice versa. Sometimes known as compound ventilation. BS, 8 radian A unit of plane angular measurement equal to the angle at the center of a circle subtended by an arc equal in length to the radius. One radian equals about 57.29 degrees . Webster 3rd radiant energy Energy that radiates or travels outward in all directions from a source. MacCracken radiated Said of an aggregate of acicular crystals that radiate from a central point. CF: spherulitic radiated pyrite See: marcasite radiating 2535

A mineral with crystals or fibers arranged around a center point, for example, stibnite. Also called divergent. Nelson radiation absorbed dose The basic unit of absorbed dose of ionizing radiation. One radiation absorbed dose (abbrev., rad) equals the absorption of 100 ergs of radiation energy per gram of matter. Lyman radiation damage a. A general term for the alteration of properties of a material arising from exposure to X-rays, gamma rays, neutrons, heavy-particle radiation, or fission fragments in nuclear fuel material. ASM, 1 b. Damage done to a crystal lattice (or glass) by passage of fission particles or alpha particles from the nuclear decay of a radioactive element residing in or near the lattice. See also: metamict mineral AGI radiation detector A device used either on the surface or in drill holes to detect and/or indicate the occurrence or the nearby presence of radioactive minerals. Also called electronic logger; gamma-ray detector; Geiger counter; Geiger-Mueller counter; Geiger-Mueller probe; scintillation counter; scintillometer. Long radiation log See: radioactivity log radiation pyrometer a. A device for ascertaining the temperature of a distant source of heat, such as a furnace. A concentrated group of thermocouples, called a thermopile, is used. Radiant heat from the furnace or object is focused by a lens onto the thermopile. Radiation pyrometers may be used for measuring temperatures to 7,000 degrees F (3,870 degrees C). The device is used in automatic control systems in mineral dressing and other processes. Nelson b. Pyrometer that determines temperature by measuring the intensity of radiation from the hot body. radiation survey A study of factors in any process or device involving radiation that could cause danger to any persons working near the process or device. NCB radiation-type gage 2536

An instrument for measuring the density or percentage of solids in slurries flowing through pipes. It normally uses a gamma-ray source, usually cesium-137 or cobalt-60, mounted in a lead-shielded holder on one side of the pipe. A radiation detector is mounted on the opposite side. Since the absorption of the gamma radiation, as it passes through the slurry, varies as a function of the density of the slurry, the change in radiation received by the radiation detector is representative of the specific gravity or percentage of solids in the slurry. See also: differential pressure flowmeter radioactive a. Generally, the property possessed by certain elements, such as uranium, of spontaneously emitting alpha, beta, and/or gamma rays by the disintegration of the nuclei of their atoms. Long b. Of, relating to, caused by, or exhibiting radioactivity. Abbrev., RA. Webster 3rd radioactive decay a. The change of one element to another by the emission of charged particles from the nuclei of its atoms. AGI b. The spontaneous disintegration of the atoms of certain nuclides into new nuclides, which may be stable or undergo further decay until a stable nuclide is finally created. Radioactive decay involves the emission of alpha particles, beta particles, and other energetic particles, and usually is accompanied by emission of gamma rays and by atomic de-excitation phenomena. It always results in the generation of heat. Syn: radioactive disintegration radioactive disintegration See: radioactive decay radioactive dusts Dusts that are injurious because of radiation. They include ores of uranium, radium, and thorium. Hartman, 2 radioactive element Applied to certain unstable atoms, the nuclei of which spontaneously disintegrate, emitting particles and rays, eventually reverting through a series of such emissions into an atom having a stable nucleus and a different atomic number. Radium, e.g., becomes lead-207. MacCracken radioactive mineral One of six radioactive elements that occur naturally: potassium, rubidium, thorium, uranium, and associated radium, samarium, and lutecium. Thorium commonly occurs in 2537

monazite, a sparsely scattered accessory mineral of certain granites, gneisses, and pegmatites. It is concentrated, however, by weathering processes in sands and gravels as commercial placer deposits along rivers and beaches. The most important primary uranium ore minerals are davidite and uraninite, esp. pitchblende, the massive variety. These minerals are of rather underspread occurrence in certain granites and pegmatites and occur as secondary minerals in metallic vein deposits. The secondary uranium minerals, however, are more underspread and more numerous than the primary uranium ore minerals. Secondary uranium minerals are found in weathered and oxidized zones of primary deposits and, also, in irregular flat-lying sandstones, such as those in the Colorado Plateau, where the uranium mineralization was precipitated from solutions. Carnotite, the potassium uranium vanadate of conspicuous yellow color, is perhaps the most important of the secondary uranium ore minerals. Others are tyuyamunite, which is closely related to carnotite, and the torbernites and autunites which are uranium minerals. radioactive series A succession of nuclides, each of which transforms by radioactive disintegration into the next until a stable nuclide results. The first member is called the parent, the intermediate members are called daughters, and the final stable member is called the end-product. Four radioactive series are the uranium series, the thorium series, the actinium series, and the neptunium series. Glasstone radioactive tracer element A radioactive isotope of an element used to study a process by observing the intensity of radioactivity. radioactive waste Equipment and materials from nuclear operations that are radioactive and for which there is no further use. Wastes are generally referred to as high-level (having radioactivity concentrations of hundreds to thousands of curies per gallon or per cubic foot); low-level (in the range of 1 microcurie per gallon or per cubic foot); and intermediate (between these extremes). Lyman radioactivity The spontaneous decay or disintegration of an unstable atomic nucleus, accompanied by the emission of radiation. See also: radioactive decay Lyman radioactivity log a. A log of a borehole obtained through the use of gamma, neutron, or other radioactivity logging methods. b. The generic name for well logs whose curves derive from reactions 2538

of atomic nuclei involving the behavior of gamma rays and/or neutrons. Except for the natural gamma-ray log and the spectral gamma-ray log, they record the response of rocks very near the well bore to bombardment by gamma rays or neutrons from a source in the logging sonde. Most can be obtained in cased, empty, or fluid-filled well bores. Varieties include: density log; neutron log; neutron-activation log; epithermal-neutron log; pulsed-neutron-capture log. Syn: radiation log; nuclear log. See also: gamma-ray well log; spectral gamma-ray log; neutron log. AGI radioactivity prospecting Exploration for radioactive minerals utilizing various instruments, generally a Geiger counter or scintillation counter, by measuring the natural radioactivity of earth materials. Dobrin radioaltimeter Equipment carried in survey aircraft to ensure constant height above ground (not sea) level of 300 ft or 500 ft (91.4 m or 152.4 m)--a critical factor in certain airborne geophysical prospecting and aerial mapping surveys. See also: profile flying radiocarbon Radioactive carbon, esp. carbon-14, but also carbon-10 and carbon-11. AGI radiocarbon dating See: carbon-14 dating radiochemistry The chemical study of artificial and naturally occurring radioactive materials and their behavior. It includes their use in tracer studies and other chemical problems. AGI radioelement A form or sample of an element containing one or more radioactive isotopes. radiogenic Produced by radioactive transformation. Thus, uranium minerals contain radiogenic lead and radiogenic helium. The heat produced within the earth by the disintegration of radioactive nuclides is radiogenic heat. radiograph 2539

a. A photographic shadow image resulting from uneven absorption of radiation in the object being subjected to penetrating radiation. ASM, 1 b. A picture produced upon a sensitive surface (such as a photographic film), by a form of radiation other than light; specif., an X-ray or a gamma-ray photograph. See: roentgenogram radiography a. A nondestructive method of internal examination in which metal or other objects are exposed to a beam of X-ray or gamma radiation. Differences in thickness, density, or absorption caused by internal discontinuities are apparent in the shadow image either on a fluorescent screen or on a photographic film placed behind the objects. ASM, 1 b. The use of penetrating ionizing radiation to examine solid material. When the source of radiation is internal, such as an implanted radioactive tracer, the technique is known as autoradiography. Lyman radiohalo See: pleochroic halo radioisotope a. An unstable isotope of an element that decays or disintegrates spontaneously, emitting radiation. Lyman b. Radioisotope is loosely used as a syn. for radionuclide. See also: radium; radon. Syn: unstable isotope Radiolaria a. Subclass of the Sarcodina consisting of marine protozoans that possess complex internal siliceous skeletons. b. Silica rock formers. Mason radiolarian ooze Deposits of siliceous ooze made up largely of radiolarian skeletons and are formed at depths between 13,000 ft and 25,000 ft (4.0 km and 7.6 km). AGI radio link Radio signal unit used to control or communicate between scattered sections of mine, or to link isolated camp with other places. Pryor, 3 radiolite A spherulite composed of radially arrayed acicular crystals. radiolite survey instrument 2540

A one-shot bore-hole-surveying instrument having the horizontal (compass) and vertical indicator markings painted with a radioactive substance, such as that on the luminous dial of a watch. The positions of these markings are recorded on small, circular, photographic film. Long radiolitic a. Said of the texture of an igneous rock characterized by radial, fanlike groupings of acicular crystals, resembling sectors of spherulites. AGI b. Said of limestones in which the components radiate from central points, with the cement comprising less than 50% of the total rock. AGI radiometallography The application of X-rays to the study of the internal structure of various materials, esp. metals. Fay radiometer Essentially a heat-flow meter used to measure long-wave radiation as well as solar radiation. It can be used both for daytime and nighttime measurements and to measure the net heat transfer through a surface. Hunt radiometric assay A test to determine contained quantity of uranium. The actual uranium present may be more or less than the assay shows. See also: equilibrium; inequilibrium. Ballard radiometric ore sorter A device for separating gangue from uranium-bearing ore, after primary crushing. Nelson radiometric prospecting Use of portable Geiger-Muller apparatus for field detection of emission count in search for radioactive minerals. Pryor, 3 radiophone An FM apparatus, using the mine haulageway trolley wire for power and antenna, that permits the dispatcher to talk back and forth with his motor crews as they are moving throughout the mine. This saves stopping and starting trips to make telephone calls. Kentucky 2541

radiophyllite See: zeophyllite radiore method An electromagnetic method used in mineral exploration in which a high-frequency current is used, ranging from 30,000 to 50,000 Hz, but, if necessary, a frequency as low as 50 to 3,000 Hz, can be made available. The detecting or direction-finding coil, mounted on a tripod, has the form of a pair of spectacles and is equipped with an amplifier and head telephone. When the exciting coil is energized, a current is caused to flow in the conductor and a secondary electromagnetic field is set up around the conductor. The detecting coil is affected by both the primary field from the exciting coil and the secondary field. Lewis radium A radioactive metallic element; one of the alkaline-earth metals. Symbol, Ra. It occurs in pitchblende ore, in carnotite sands, and in all uranium minerals. See also: radioisotope radium G A name for lead-206, the stable end-product of the radioactive disintegration of uranium238 in the uranium disintegration series. Natural lead contains 23.6% of lead-206. Symbol, RaG. Syn: uranium-lead Handbook of Chemistry and Physics, 2 radiumite A mixture of black pitchblende, yellow uranotile, and orange gummite. Schaller radius Horizontal distance from the center of rotation of a crane to its hoisting hook. Nichols, 1 radius of curve A term used in laying mine track; the calculated radius of an arc that will connect two pieces of track (at a desired angle of direction from each other) with a smooth curve section. radius of gyration The value used when calculating the slenderness ratio of pillars and struts. If A is the cross-sectional area in inches of the pillar or strut and I is its moment of inertia, the radius of gyration is (I/A), generally known as K. Hammond 2542

radius of rupture In crater tests, the average distance from the center of the explosive charge to the periphery of the crater at the surface. Duvall radius ratio a. The ratio of the radius of the smaller ion to that of the larger ion. It may not exceed 1. Hurlbut b. The ratio of the radius of the smaller ion to that of the larger; commonly cation to anion. Radius ratios are used to predict coordination numbers of anions about cations in ionic crystal structures. CF: Pauling's rules radon a. A heavy, radioactive, gaseous element; inert; the heaviest known gas. Symbol, Rn. Formed by the disintegration of uranium. Used similarly to radium in medicine. Radon build-up is a health consideration in uranium mines. Handbook of Chemistry and Physics, 3 b. Heaviest known gas. Colorless as a gas; yellow to orange-red, phosphorescent, opaque crystals; sp gr of liquid, 4.4 (at -62 degrees C); and of solid, 4.0; soluble in water; and slightly soluble in alcohol and in organic liquids. All 18 known isotopes from radon-204 to radon-224 are radioactive. Radon-222 emanates from thorium; half-life, 54.5 s; and an alpha particle emitter; and radon-219 or actinon emanates from actinium; half-life, 3.92 s; and an alpha particle and a gamma ray emitter. One part of radon exists in 1 sextillion parts of air. Handbook of Chemistry and Physics, 2 radon daughter A radioactive element produced in the disintegration of radon. Syn: radon progeny radon progeny The short-lived decay products of radon, an inert gas that is one of the natural decay products of uranium. The short-lived radon progeny (i.e., polonium-210, lead-214, bismuth-214, and polonium-214) are solids and exist in air as free ions or as ions attached to dust particles. The U.S. Mine Safety and Health Administration has established radiation protection standards that limit a miner's radon progeny exposure to a concentration of 1.0 WL and an annual cumulative exposure to 4 WLM. Each WLM is determined as a 173-h cumulative, time weighted exposure. Syn: radon daughter raffinate The aqueous solution remaining after the metal has been extracted by the solvent; the tailing of the solvent extraction system. 2543

raft See: float coal rafter timbering A method of mine timbering in which the timbers appear like roof rafters. rafting a. The transporting of sediment, rocks, silt, and other matter of land origin out to sea by ice, logs, etc., with subsequent deposition of the rafted matter when the carrying agent disintegrates. Hunt b. Matting or agglomerating of powdered coal. Bennett rag a. In British usage, any of various hard, coarse, rubbly, or shelly rocks that weather with a rough irregular surface; e.g. a flaggy sandstone or limestone used as a building stone. The term appears in certain British stratigraphic names, as the Kentish Rag (a Cretaceous sandy limestone in East Kent). Syn: ragstone b. Any of various hard rocks, as a quartzose mica schist used for whetstones or a hard limestone used in building. Webster 3rd c. A large roofing slate left rough on one side. Webster 3rd d. To break (ore) into lumps for sorting; to cut or dress roughly (as a grindstone). Webster 3rd ragged rolls Rolls with rough surfaces to facilitate the gripping of the steel in the first stages of rolling, as distinguished from the smooth-finishing rolls. Mersereau, 2 ragging a. The rough washing or concentration of ore or slimes on a rag frame. Nelson b. In roll crushers, grooves cut in surface to improve grip on feed, and increase angle of nip. Also, in ore concentration in jigs, oversized bedding placed on jig screens. Pryor, 3 c. See: bedding raggy stone Thin-bedded or flaggy sandstone. TIME ragstone See: rag rail 2544

The chain or inner surface of a crawler. Nichols, 1 rail gage The distance or width between the inner edges of the heads of the rails; (1) in coal mining, the rail gage for tub and car tracks ranges from 2 to 3 ft (0.6 to 0.9 m), and 2-1/3 ft (0.7 m) is considered a satisfactory compromise; (2) the standard gage for railway tracks is 4 ft, 8-1/2 in (1.44 m) and, (3) in metal mining, the rail gage ranges from 1-1/2 to 2-1/2 ft (0.46 to 0.76 m). See also: track gage rail haulage system A materials transportation system consisting of gondola cars, and the steel rails on which the cars are moved about with a suitably powered traction unit as a locomotive. rail riffles These may be either longitudinal or transverse and consist of rails of various sizes, placed in sets usually upside down, either longitudinally in the sluice box, or transversally across the box. They wear well, are rigid, and give some security against theft of gold from the sluice boxes. Griffith rails Specially shaped steel bars which, when laid parallel on crossties and fastened, form a track for vehicles with flanged wheels. rail track ballast Material placed around and between track ties and tamped under sides and ends of the ties to bring the track to proper grade by filling the space between the bottom of the ties and the graded roadbed. rainbow chalcedony Eng. A variety of chalcedony of thin concentric layers, which, when cut across, exhibit an iridescence resembling the colors of the rainbow. Fay rainbow quartz See: iris quartz rain chamber

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A chamber in which fumes, such as those from molten metal, may be condensed by a water shower. Standard, 2 rain gage A device used to measure precipitation (melted snow, sleet, or hail as well as rain). It consists of a receiving funnel, a collecting vessel, and a measuring cylinder. Syn: pluviometer; hyetometer; snow gage. AGI rainwash a. The washing-away of loose surface material by rainwater after it has reached the ground but before it has been concentrated into definite streams; specif. sheet erosion. Also, the movement downslope (under the action of gravity) of material loosened by rainwater. It occurs esp. in semiarid or scantily vegetated regions. AGI b. The material that originates by the process of rainwash; material transported and accumulated, or washed away, by rainwater. AGI c. The rainwater involved in the process of rainwash. AGI raise a. A vertical or inclined opening in a mine driven upward from a level to connect with the level above, or to explore the ground for a limited distance above one level. After two levels are connected, the connection may be a winze or a raise, depending upon which level is taken as the point of reference. Syn: raised shaft See also: raise borer These machines are used to produce a circular excavation either between two existing levels in an underground mine or between the surface and an existing level in a mine. In raise boring, a pilothole is drilled down to the lower level, the drillbit is removed and replaced by a reamer head having a diameter with the same dimension as the desired excavation and this head then is rotated and pulled back up towards the machine. SME, 1 raise climber Equipment used in an opening (raise) that is mined upward. MSHA, 4 raised shaft See: raise raising Excavating a shaft or steep tunnel upward. See also: raise; rise. Nelson 2546

rait Mid. To split off the walls or sides of underground workings. Called rosh in Leicestershire. Syn: rate rake a. As used by diamond drillers and bit manufacturers, rake is the angle, measured in degrees, formed by the leading face of a cutting tool and the surface behind the cutting edge. See also: negative rake; positive rake. Long b. The inclination of anything from the vertical; said of mineral veins, faults, etc. See also: pitch c. A timber placed at an angle. See also: rakers d. Shale containing ironstone nodules. BS, 11 rake blade A dozer blade or attachment made of spaced tines. Nichols, 1 rake classifier A type of mechanical classifier utilizing reciprocal rakes on an inclined plane to separate coarse from fine material contained in a water pulp, overflowing the fine material and discharging the coarse material by means of an inclined raking system. rakers Slanting props placed at the end of a drift set to keep the timbers steady when blasts go off. See also: rake rake thickener Equipment for thickening in which the concentrated suspension settles in a container of circular section and is delivered mechanically to one or more discharge points by a series of arms revolving slowly around a central shaft. BS, 5 rake vein a. A steeply inclined crosscutting irregular mineralized fracture or fissure. BS, 11 b. Rake vein and gas vein are synonymous; it is said that they are lodes filling distinct fissures. Their course in irregular; their dip, as a rule, vertical. Ricketts c. A vein or lode cutting through the strata. raking strut A strut set at an angle to the vertical to support timbering during excavation. Hammond 2547

Raky boring method A method of boring somewhat similar to Fauck's. Hollow steel rods 2 in (5.08 cm) in diameter are used with a mud flush. A walking beam, fitted with steel springs, imparts from 80 to 120 short blows/min to the chisel. Nelson Raleigh's law In 1909 Lord Raleigh established the general law of fluid flow: R = wV2 (f)(wVD/m), where R = resistance of flow, w = density of fluid, V = velocity of flow, D = diameter of pipe, m = viscosity of fluid, f = signifies function. For any particular value of (wVD)/m, using any combination of quantities, there will be a definite corresponding value of R/wV2 . Lewis ralstonite An isometric mineral, Nax Mgx Al2-x (F,OH)6 .H2 O ; structurally related to the pyrochlore group; occurs as octahedra. Ralston's classification of coal A classification based on the percentage of carbon, hydrogen, and oxygen in the ash-, moisture-, sulfur-, and nitrogen-free coal. These figures are plotted on trilinear coordinates giving well-defined zones of bituminous coals, lignites, peats, etc. Miall ram a. To stem; tamp. Mason b. Black ram, bog iron ore; gold ram, gold ore. Arkell c. The plunger of a pump. Zern d. A mechanical pusher for forcing (discharging) coke from a byproduct coke oven. Mersereau, 2 e. An appliance for exerting a pressure on face equipment, such as steel supports, conveyors, or plows. See also: hydraulic ram; pneumatic ram. Nelson ramdohrite A monoclinic mineral, Ag3 Pb6 Sb11 S24 ; forms dark-gray twinned prismatic to lanceshaped crystals; at Potosi, Bolivia. CF: andorite rammel Loose stone, or waste rock; loose sandy or stony barren soil; mixed shale and sandstone. Also spelled: rammell. rammelsbergite 2548

An orthorhombic mineral, NiAs2 ; loellingite group; trimorphous with pararammelsbergite and krutovite; metallic; tin white; sp gr, 7.1; in vein deposits. Syn: white nickel rammer A rod for charging and stemming shotholes. See also: stemmer Nelson ramming a. See: stemming; tamping. b. See: scaling ramming and patching refractories Those which can be rammed to form a monolithic furnace lining or special shapes. ram operator In bituminous coal mining, a laborer who tends operation of, adjusts, and repairs pumping devices (rams) used in low places in shallow mines to force a portion of the mine water to the surface by utilization of the flow of the entire amount. Nearly obsolete. See: pumper ramp a. A fault that is a gravity (normal) fault near the surface but curves through the vertical to dip in the opposite direction at depth, where the displacement is that characteristic of a thrust. b. A portion of a thrust fault that cuts across formational contacts in a short distance. AGI c. An incline connecting two levels in an open pit or underground mine. ram pump a. A pump consisting essentially of a plunger or ram which forces the contained water into the discharge pipe. See also: force pump Nelson b. A single-acting reciprocating pump that has a ram instead of a piston. The ram has a constant diameter and does not fit closely in the cylinder, pumping only by displacement. Hammond ramp valley a. A valley produced by the ramping or upthrusting of two masses, one on either side of an intervening strip. b. A valley bounded by thrust faults. ram scraper

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A plow-type machine hauled by an endless chain at a speed of 6 ft/s (1.83 m/s). The ram scraper is pressed toward the face by the tension of the return strand, the return sheave being located inby for this purpose. Syn: Peissenberg ram. See also: manless face. ramsdellite An orthorhombic mineral, MnO2 ; trimorphous with akhtenskite and pyrolusite. rance a. A prop set against the coal face that is undermined. Fay b. A dull red marble with blue and white markings. From Belgium, and sold in the United States as Belgian marble. Webster 2nd; Fay rance marble a. A white, hard, shining grit, striped red. Arkell b. A kind of variegated marble from Hainault, Belgium. Arkell rand S. Afr. A ridge, range of hills, or highland on either side of a river valley. Rand An abbrev. of Witwatersrand, the gold fields in the Republic of South Africa. Randolph process A modification of the series process of copper refining in which the electrodes lie horizontally, the top surface of each one acting as anode, the lower as cathode. Theoretically, it has the advantage of extremely low metal losses and great purity of copper. See also: Hayden process; Smith process. Liddell random The direction of a rake vein. random error Any error that is wholly due to chance and does not recur; an accidental error. Ant: systematic error. AGI random line 2550

a. A trial line, directed as nearly as may be toward a fixed terminal point that is invisible from the initial point. Seelye, 2 b. A random traverse; i.e., a traverse run from an initial to a terminal point to determine the direction of the latter from the former. Seelye, 2 random orientation See: random set random pattern The setting of diamonds in a bit crown without regard to a geometric pattern--without regular and even spacing. See also: random set Long random sample a. A sample take without plan or pattern. Nelson b. A subset of a statistical population in which each item has an equal and independent chance of being chosen; e.g., a sample chosen to determine (within definied limits) the average characteristics of an orebody. AGI random set The setting of diamonds in a bit crown without regard to the attitude of their vector properties. Syn: random orientation See also: random pattern random stone A term applied by quarry personnel to quarried blocks of any dimensions. Randupson process A system of molding in which the molds are made of a mixture of silica sand and cement with water added. Osborne rang a. In the CIPW classification of igneous rocks, that division below order. b. A Ceylonese term for gold; from rangwelle meaning golden sand. range a. An area in which a mineral-bearing formation crops out; e.g., the iron range and copper range of the Lake Superior region; a mineral belt. AGI b. An established or welldefined line or course whose position is known and along which soundings are taken in a hydrographic survey. AGI c. Any series of contiguous townships (of the U.S. Public 2551

Land Survey system) aligned north and south and numbered consecutively east and west from a principal meridian. AGI d. The distribution of a genus, species, or other taxonomic group of organisms through geologic time. AGI e. An orderly arrangement or family of diamond-drill fittings, such as casing, core barrels, drill rods, etc., with diameters appropriately related to each other and intended to be used together. Ranges commonly are designated by letter names, using letters such as E, A, B, and N individually or as the first letter in two- and three-letter names. CF: group f. For a spherical model, the distance at which the model reaches its maximum value, or sill. For the exponential and gaussian models, which approach the sill asymptomatically, it means the "practical" or "effective" range, where the function reaches approximately 95% of the maximum. The nugget model effectively has a sill with a range of zero: the linear model uses "sill/range" merely to define the slope. range line One of the imaginary boundary lines running north and south at six-mile intervals and marking the relative east and west locations of townships in the U.S. public-land survey; a meridional township boundary line. CF: township line range of stress The range between the upper and lower limit of a cycle of stress, such as is applied in a fatigue test. The midpoint of the range is the mean stress. CTD range pole a. A 6- to 12-ft (2- to 3-m) wooden or metal pole painted in contrasting colors at 1-ft (0.3-m) intervals. It is used in surveying to mark lines of sight, stations, etc. b. See: picket c. A metal rod, pointed at one end, and usually painted alternately red and white at 1-ft intervals; used by surveyors as a line of sight. Syn: ranging rod ranging rod See: range pole rank a. Describes the stage of carbonification attained by a given coal. IHCP b. The place occupied by a coal in a classification. Specifications of the American Society for Testing and Materials cover the classification of coals according to their degree of metamorphism, or progressive alteration, from lignite to anthracite. For a complete description of this classification, consult ASTM Designation: D 388. ASTM c. When applied to coal, denotes its age in geological formation, not necessarily denoting quality. BCI d. The position of a coal relative to other coals in the coalification series from brown coal (low rank) to anthracite (high rank), indicating its maturity in terms of its 2552

general chemical and physical properties. BS, 11 e. Those differences in the pure coal material due to geological processes designated as metamorphic, whereby the coal material changes from peat through lignite and bituminous coal to anthracite or even to graphite. AGI f. All coallike fossil fuels form a continuous and progressive series, ranging from lignite, through the various bituminous coals, to anthracite. It is the position of a particular coal in this series that determines its rank. Therefore, lignite is a low-rank coal while anthracite is a high-rank coal. See also: coalification; grade; Hilt's Law; coal rank. Nelson g. A term primarily devised to indicate the position of a fuel in the series peat-anthracite, probably best measured by the percentage of carbon (ashless, dry basis). Thus rank depends on the degree of metamorphism of coal, and increase of rank is, in general, marked by the decrease of volatiles and moisture. Tomkeieff h. The term rank may also be applied to other series, such as the sapropelic coal series or the bitumen series. CF: type Tomkeieff Rankine scale An absolute-temperature scale in which a measurement interval equals a Fahrenheit degree and in which zero degrees is equal to -459.67 degrees F (-273.16 degrees C). Named for William J.M. Rankine, a Scottish physicist. See also: temperature Rankine's formula An empirical formula giving the collapsing load for a given column. CTD Rankine's theory The state of stress theory as developed by Rankine in 1860 for application to earth pressures. He formulated that the pressure on a vertical retaining wall restraining earth with a horizontal surface is (1 - sinphi ) / (1 + sinphi ) multiplied by the soil density for each foot depth of soil retained, where phi is the angle of internal friction of the soil. The value (1 - sinphi ) / (1 + sin#2f) is the coefficient of active earth pressure. Hammond rankinite A monoclinic mineral, Ca3 Si2 O7 ; dimorphous with kilchoanite; rare in contact metamorphic rock, but common in blast furnace slag. rank variety Variety in coals brought about as a result of progressive metamorphism. More or less arbitrarily, although carefully, selected chemical criteria are used to differentiate coals of different rank. Physical criteria are also used but are more difficult of application. AGI ransomite 2553

A monoclinic mineral, CuFe2 (SO4 )4 .6H2 O ; forms slender sky-blue prisms; at Jerome, AZ. rap a. To warn workers in an adjoining working place of a blast, when the working places are separated by only a small pillar, by knocking on the pillar with a tool or bar. b. To test the roof by tapping it with a stick or bar. c. To signal by knocking on a steam, water, or air pipe. Fay rapakivi A hornblende-biotite granite containing large rounded crystals of orthoclase mantled with oligoclase. The name has come to be used most frequently as a textural term where it implies plagioclase rims around orthoclase in plutonic rocks. rapid blow drilling A drilling method utilizeing a great number of short blows in quick succession rather than a few heavy blows from a relatively considerable altitude. In this method, the bit is fixed either to a rod or to a rope, so that it pounds the bottom in quick succession with short blows and at the same time rotates. Stoces rapid excavation An improved cycle and system of operation to achieve rapid advance and continuous operation in low-drillability rock. SME, 1 rapid plow A fast moving plow with picks attached. The rapid plow is a continuous longwall cutter loader capable of working unattended on the face. For this reason, it is one of the safest machines in operation. See also: hard-coal plow rap-in Som. To wedge down blocks of stone in underground quarries. rappage Excess in size of a casting because the mold is larger than the pattern when the latter is unduly rapped, as with the hand, for drawing. Standard, 2 rapping 2554

In foundry work, loosening of pattern before its withdrawal from molding sand in flask. Pryor, 3 rapping roller An eccentric roller or a roller fitted with devices such as bars welded longitudinally along its outer casing, so arranged as to rap the belt and knock off fine coal or dust adhering to the return belt, or to centralize the coal on the carrying belt. Nelson rare earths Oxides of a series of 15 metallic elements, from lanthanum (atomic number 57) to lutetium (71), and of two other elements; yttrium (39), and scandium (21). These elements are not esp. rare in the Earth's crust, but concentrations are. The rare earth metals resemble one another very closely in chemical and physical properties, thus making it most difficult to separate them. The rare earths are constituents of certain minerals, esp. monazite, bastnaesite, and xenotime. Abbrev: REE. AGI rarefaction a. The process or act of making rare or less dense; increase of volume, the mass remaining the same: now usually of gases; also, the state of being rarified; as, the rarefaction of the atmosphere on a high mountain. Standard, 2 b. Diminution of air pressure below normal, as in alternate half-cycles in the transmission of a sound wave past a point. CTD rashings A very friable carbonaceous clay, with numerous slickensides and sometimes streaks of coal. Rashings may underlie, overlie, or be interstratified with the coal; a very weak material and breaks up around the face supports. See also: brashings Rasorite See: kernite rasp An instrument used in a borehole for fishing operations, for reducing the length of the box, or for coupling lost tools. Also called mill; rose bit. Long raspberry spar a. See: rhodochrosite b. Pink tourmaline. 2555

raspite A monoclinic mineral, PbWO4 ; dimorphous with stolzite; forms small tabular brownishyellow crystals having intense adamantine luster; at Broken Hill, N.S.W., Australia. ratchet A set of teeth that are vertical on one side and sloped on the other; holds a pawl moving in one direction, but allows it to move in another. Nichols, 1 ratchet-and-pawl mechanism A cogwheel (ratchet) with which a single pivoted catch (pawl) engages, thereby preventing any backward turning. Hammond ratchet drill A hand drill in which the drill holder is revolved intermittently by a lever through a ratchet wheel and pawl. A drill used for boring slate. Webster 3rd; Fay ratchet man The worker who operates the duckbill loader when mining with duckbill conveyors. Lewis rate See: rait rate action (nonstandard) As used in flotation, the component of proportional plus rate action or of proportional plus reset plus rate action for which there is a continuous linear relation between the rate of change of the controlled variable and the position of a final control element. Fuerstenau rated capacity The load that a new wire rope or wire rope sling may handle under given operating conditions and at an assumed design factor. rate determining step In any series or sequence of chemical reactions used to leach a product from its ore, the slowest in the chain. Pryor, 3 2556

rated horsepower a. Theoretical horsepower of an engine based on dimensions and speed. Nichols, 1 b. Power of an engine according to a particular standard. Nichols, 1 rated load The kilowatt power output that can be delivered continuously at the rated output voltage. It may also be designated as the 100% load or full-load rating of the unit. Coal Age, 1 rated output current The current derived from the rated load and the rated output voltage. Coal Age, 1 rated output voltage The current specified as the basis of rating. Coal Age, 1 rate of advance a. The distance the bit penetrates a rock formation in a unit of time, such as inches (centimeters) per minute or feet (meters) per hour. Long b. In coal mining, the number of feet (meters) between the coal face at the beginning and at the end of a workshift. rate of grade See: gradient rates of reduction In crushing practice, these rates are (1) based on crusher dimensions, wherein the largest cube that will enter is compared with the largest that can be discharged, or (receiving opening) / (discharge opening); the receiving opening is measured from the top of the movable member to the top of the stationary member; and (2) based on actual products; (a) overall reduction ratio = (mean size of feed) / (mean size of product); (b) individual reduction ratio = (size most abundant in feed) / (mean size of grading band concerned). South Australia rathite See: liveingite rathite-II See: liveingite 2557

rathole a. A hole drilled at an angle to the main hole by means of a deflection wedge. Long b. A small-diameter pilot-type hole drilled a short distance ahead of a larger diameter hole to stabilize a smaller diameter bit and core barrel when used to core a limited portion of the borehole. After core drilling is completed, the rathole is reamed out and the larger size hole advanced, usually by some noncoring method. Long c. A small sump or settling pond in which the larger sized cuttings from a drill hole are collected between the top of the drill hole and the main settling pond. Long d. A slanting hole, perhaps 25 ft (7.62 m) deep, used for adjusting or lubricating the swivel on a grief stem. The start of a hole for rotary drilling. Hess rathole bit A bit designed and used to drill the first portion of a deflected hole alongside and beyond the deflection wedge; also, a bit used to drill a rathole. CF: wedge bit rat-holing The act or process of drilling a deflected or pilot hole. See also: rathole rating The maximum capacity of a drill hoist or a prime mover, such as an engine, motor, or pump; generally the maximum safe capacity. Long rating flume A flume used for purposes of control. Hammond ratiometer An instrument used to measure the ratio of two differences in potential. AGI rational analysis a. The mineralogical composition of a material as deduced from chemical analysis. b. The resolution into chemical types of a mass of rock or coal. Francis, 2 ratio of absorption a. The percentage by weight that the absorbed water bears to the dry weight of the stone. b. The ratio (A), expressed as a percentage, of the volume (Vp) of the pore space in a rock to the weight (W) of the rock when dry, A = 100 Vp/W. Holmes, 2 2558

ratio of concentration (Weight of ore fed) / (Weight of concentrate produced). Pryor, 3 ratio of enrichment The ratio of the percentage of valuable material in the concentrate to the percentage of the valuable material in the original material. ratio of reduction a. The relationship between the maximum size of the stone which will enter a crusher, and the size of its product. Nichols, 1 b. The ratio of enrichment with respect to the sought mineral: (Assay value in feed) : (Assay value in concentrate). See also: reduction ratio ratio of size reduction Ratio of the upper particle size in the crushed material to the upper particle size of the feed material. BS, 5 rattle boxes Limonite geodes from Chester County, PA. Schaller rattler a. York. Cannel coal. b. Scot. Inferior gas coal; sandy shale. c. U.K. A variety of gas coal that fetched high prices and was reputed to ignite with a match. It is hard, compact, uniform, bright, brittle, fine-grained, slightly sonorous when struck, and resembling jet but not so brilliant. Arkell d. A revolving steel drum with a charge of metal spheres used for testing the abrasive resistance of brick. e. A device for shaking out the cores from small castings, such as a tumbling barrel. rattler test A method for evaluating the resistance of paving bricks to impact and abrasion. A sample of 10 bricks is subjected to the action of 10 cast-iron balls 3.75 in (9.53 cm) in diameter and 245 to 260 balls 1.875 in (4.76 cm) in diameter in a drum 28 in (71.12 cm) in diameter, 20 in (50.8 cm) long, rotating at 30 rpm for 1 h. The severity of abrasion and impact is reported as a percentage loss in weight. Dodd rattlesnake ore

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A gray, black, and yellow mottled ore of carnotite and vanoxite, its spotted appearance resembling that of a rattlesnake. AGI rauvite A mineral, Ca(UO2 )2 V10 O28 .16H2 O ; radioactive; purple- black; sandstone impregnation on the Colorado Plateau. ravelly ground Rock that breaks into small pieces when drilled and tends to cave or slough into the hole when the drill string is pulled, or binds the drill string by becoming wedged or locked between the drill rod and the borehole wall. Long ravine A small, narrow, deep depression, smaller than a gorge or a canyon but larger than a gully, usually carved by running water; esp. the narrow excavated channel of a mountain stream. Etymol: French, mountain torrent. AGI raw a. In ceramics, fresh from a plastic process; unbaked. Standard, 2 b. Not prepared for use by heat. Webster 3rd raw coal Coal which has received no preparation other than possibly screening. Syn: raw ore raw coal screen A screen used for dividing run-of-mine coal into two or more sizes for further treatment or disposal; usually employed to remove the largest pieces for crushing and readdition to the run-of-mine coal. BS, 5 raw dolomite a. Dolomite that has not been calcined. ARI b. Crushed dolomite used for dressing of basic open hearth bottoms and banks. AISI raw feed coal Coal supplied to a plant or machine, in which it undergoes some form of preparation. BS, 5 2560

raw fuel A fuel used in the form in which it is mined or obtained, for example, coal, lignite, peat, wood, mineral oil, natural gas. Nelson rawhide hammer A hand hammer having a rawhide head that serves to prevent bruising metal parts against which it is used. Crispin raw material The ingredients before being processed that enter into a finished product. Crispin raw mica A term commonly used for unmanufactured mica. Skow raw ore a. Ore that is not roasted or calcined. b. See: raw coal raydist A radio system for medium-range precision surveying in which the phases of two continuous-wave signals are compared. It is based on the heterodyne principle and uses low or medium frequencies. It requires a minimum number of frequencies and these frequencies usually need bear no fixed relationship with each other. Hunt Rayleigh wave a. A type of seismic surface wave having a retrograde, elliptical motion at the free surface. It is named after Lord Rayleigh, the English physicist who predicted its existence. Syn: R wave b. A surface wave associated with the free boundary of a solid. The wave is of maximum intensity at the surface and diminishes quite rapidly as one proceeds into the solid. Therefore, it has a tendency to hug the surface of the solid. Such waves have been used quite effectively in detecting surface cracks and flaws in castings. Hunt Raymond flash dryer A suspension-type dryer that employs the principle of flash drying of fine coal. The coal is transported vertically through a drying column in a stream of hot gases. The source of heat for this system is usually an automatic stoker. In this system, the hot gases are drawn into the drying column by the action of the fan connected to the cyclone collector 2561

vent. The coal to be dried is continuously introduced to the hot gas stream. Virtually instantaneous drying occurs. The dried coal and the moisture-laden gases are drawn into the cyclone collector. The dry coal drops to the bottom of the collector and the moistureladen gases are discharged by the fan to the atmosphere. See also: thermal drying Kentucky; Mitchell Raymond mill Grinding mill in which spring-loaded rollers bear against a horizontal rotating bowl-developed for coal pulverization. Pryor, 3 rays a. Negatively charged particles which leave the cathode in an evacuated tube at between 10,000 mi/s and 90,000 mi/s (approx. 16,000 km/s and 144,000 km/s), depending on voltage. Positive rays are gas ions (e.g., N+ , O+ ). X-rays are electromagnetic waves which travel at the velocity of light and are not deflected by magnetic fields. Length between 0.1 and 100 Aa (visible light lies between 4,000 and 8,000 Aa). Short X-rays are soft and long ones are hard. Rays emitted by radioactive substances are of three types, alpha, beta, and gamma. Alpha rays consist of He++ and move at some 10,000 mile/s (approx 16,000 km/s). Beta rays are electrons with speeds between 50,000 mi/s and 180,000 mi/s (approx. 80,000 km/s and 288,000 km/s); gamma rays are not charged. They move at the speed of light, but are shorter than X-rays (0.01 to 1 Aa). Pryor, 3 b. In wave propagation a ray is the trajectory that a signal travels from the source to another point (location). raywork A kind of rubble work; in the United States, any rubble work of thin and small stones. razorback A sharp, narrow ridge, resembling the back of a razorback hog. AGI razor saw A narrow saw used in excavating limestone. Webster 3rd razor stone See: novaculite reach

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a. An arm of the sea extending up into the land; e.g. an estuary or bay. AGI b. A continuous and unbroken expanse or surface of water or land. AGI c. An unstated but specific distance; an interval. AGI d. The length of a channel, uniform with respect to discharge, depth, area, and slope. AGI e. The length of a channel for which a single gage affords a satisfactory measure of the stage and discharge. AGI f. The length of a stream between two specified gaging stations. AGI g. A relatively long, straight section of water along a lake shore; also, a narrow arm of a lake, reaching into the land. AGI h. A straight, continuous, or extended part of a stream, viewed without interruption (as between two bends) or chosen between two specified points; a straight section of a restricted waterway, much longer than a narrows. AGI reactance The part of the impedance of an alternating-current circuit that is due either to capacitance or inductance or to both and that is expressed in ohms. Webster 3rd reaction border See: reaction rim; corona. reaction curve See: cotectic line reaction line See: cotectic line reaction pair Any two minerals, one of which crystallizes at the expense of the other by reaction with a melt; esp. two adjacent minerals in a reaction series. reaction principle A relationship between liquid and crystals during crystallization, esp. during fractionation, whereby crystals and liquid change composition in response to changing temperature and pressure. CF: reaction series reaction rim A rind of one mineral surrounding another and presumably crystallized by reaction of the core mineral with surrounding fluids. CF: corrosion border reaction series 2563

The sequence of minerals produced by reaction between liquid and crystals during crystallization of a complex magma. Bowen's reaction series has a continuous side (calcic to alkalic plagioclase) and a discontinuous side (olivine-pyroxene-amphibolebiotite). reaction-zone width In explosives, the distance that detonation advances before the products of combustion expand by an appreciable percentage. Leet, 2 reactive Readily susceptible to chemical change. Osborne reactive reagent Substance, solution, or gas susceptible to chemical change, or used in influencing such change. Pryor, 3 reactive silica The silica, SiO2 , present within various clay minerals occurring in bauxite. During the Bayer process digestion of bauxite, this silica reacts with comparable amounts of alumina to form insoluble sodium aluminum silicate, which is lost as refinery plant residue. reactivity a. A measure of ease of ignition and response to the controls varying the rate of burning. It is used particularly in connection with fuels for transport gas producers and low volatile fuels used for open fires. Nelson b. An assessment of the speed of reaction of a coal with oxygen under specified conditions. BS, 4 readily extractable metal As used in geochemical prospecting, refers to the content of a metal that can be extracted from weathered rock, overburden, or stream sediment, by weak chemical reagents. Syn: cold-extractable metal Reading jig A plunger-type jig of relatively simple design with only a single plunger being manually controlled. The hutch compartment is round for good water distribution. Mitchell realgar 2564

a. Arsenic monosulfide, AsS, contains 70.1% elemental arsenic. Sanford b. A monoclinic mineral, AsS ; dimorphous with pararealgar; red to orange; soft; in ore veins, hot springs, and as a volcanic sublimate. Syn: red arsenic; sandarac; red orpiment. real property Includes mining claims, dumps, water rights, and ditches. Ricketts ream To enlarge the hole by redrilling with a special bit. Wheeler, R.R. ream back The act or process of enlarging a squeezed or cave-obstructed borehole to its original size by reaming as the drill string is pulled. Syn: reverse reaming reamer A rotary-drilling tool with a special bit used for enlarging, smoothing, or straightening a drill hole, or making the hole circular when the drill has failed to do so. See also: reaming bit; reaming shell; reamer. Also called gage stone. AGI reamer bit See: reaming bit reamer shell a. A cutter just above a diamond bit, used to assure a full-size hole. Nichols, 1 b. See also: reaming shell reamer stone See: gage stone reaming The act or process of enlarging a borehole. Long reaming bit A bit used to enlarge a borehole. Also called broaching bit; pilot reaming bit. Syn: reamer; reamer bit. Long 2565

reaming diamond See: gage stone reaming pilot a. See: pilot b. A smooth bar used to guide a reaming bit or casing bit in the hole. BS, 9 reaming pilot adapter An adapter or coupling in a reaming pilot assembly that attaches the flush-joint casing to the casing reaming shell and the reaming pilot horn by pin and box threads, respectively. Long reaming pilot horn An adapter or coupling in a reaming pilot assembly attached to the reaming pilot adapter. It passes through the reaming shell and casing bit to which is attached the pilot bit. Long reaming ring See: reaming shell reaming shell a. A short tubular piece designed to couple a bit to a core barrel. The outside surface of the reaming shell is provided with inset diamonds or other cutting media set to a diameter to cut a specific clearance for the core barrel. See also: reamer; reamer shell. Syn: reaming ring Long b. Sets of two or more shells that are alternated every 50 ft (15.24 m) to keep loss in gauge to the hole uniform. The shell is changed when wear reaches 0.012 in (0.03 cm) below the original set diameter. rebar See: reinforcing bar recalescence A phenomenon, associated with the transformation of gamma iron to alpha iron on the cooling (supercooling) of iron or steel, revealed by the brightening (reglowing) of the metal surface owing to the sudden increase in temperature caused by fast liberation of the latent heat of transformation. Syn: point of recalescence recarburize 2566

a. To increase the carbon content of molten cast iron or steel by adding carbonaceous material, high-carbon pig iron, or a high-carbon alloy. ASM, 1 b. To carburize a metal part to return surface carbon lost in processing. ASM, 1 recarburizing Introducing spiegeleisen into the converter after the blow to add the desired element. Mersereau, 2 recast To form anew by running, as molten metal, into a mold; cast again; as, to recast a cracked bell. Standard, 2 receiving hopper A hopper used to receive and direct material to a conveyor. Recent The later of the two geologic epochs comprised in the Quaternary period, in the classification generally used; Holocene. Also, the deposits formed during that epoch. Recent includes the geologic time and deposits from the close of the Pleistocene (glacial) epoch until and including the present. receptor See: acceptor recession Going back, as the gradual retreat of a waterfall or an erosional escarpment, the melting back of a glacier, or the withdrawal of a body of water so that the shoreline moves successively farther away from the higher land. Stokes recharge a. The processes by which water is absorbed and added to the zone of saturation, either directly into an aquifer or indirectly by way of another formation; also, the quantity of water so added. b. Putting water brought from elsewhere into a body of ground water to augment ground-water supply. See also: intake area reciprocal lattice

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An array of points, each point at a distance that is the reciprocal of the d spacing between planes in the direction normal to each set of parallel planes as measured from the origin. Each reciprocal-lattice point may be associated with Bragg diffraction in a crystal. CF: crystal lattice; direct lattice; X-ray diffraction. reciprocal strain ellipsoid In elastic theory, an ellipsoid of certain shape and orientation that under homogeneous strain is transformed into a sphere. CF: strain ellipsoid reciprocating Having a straight back-and-forth or up-and-down motion. Nichols, 1 reciprocating drill A piston drill often referred to as a hammer drill. Hammond reciprocating engine Any steam or internal-combustion engine, which has a piston moving under pressure within a cylinder. Hammond reciprocating feeder a. A feeder in which the material is carried on a plate subjected to a reciprocating motion and so constructed that when the plate moves in the reverse direction the material remains stationary. The rate of feed is normally varied by adjusting the stroke of the reciprocating plate. See also: plate feeder b. A device used to empty a bin or hopper from the bottom by horizontal reciprocating action of its parts, usually after primary crushing. ACSG, 2 reciprocating flight conveyor A reciprocating beam or beams with hinged flights arranged to advance bulk material along a conveyor trough. See also: grit collector reciprocating pump A pump consisting of a piston or plunger which lifts water to a higher level by a series of to-and-fro movements. See also: pump Nelson reciprocating screen dryer

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Usually an inclined reciprocating screen on which the coal travels and through which the hot gases pass. The screen may eliminate moisture in coal up to 2-1/2 in (6.4 cm) in size. It may also serve as a fine coal dryer to treat coals down to 1/8 in (0.32 cm). Nelson recirculating water Circulating water that has been in the circuit for more than one cycle, often recovered from a collecting device such as a thickener from which the clarified water is circulated back into the process stream. recirculation The continuous circulation of all or some part of the same air in part of a mine ventilation system. BS, 8 recirculation of air A term describing a condition in which the ventilating air current is returned to the face repeatedly along a circuitous path. It may happen in the case of auxiliary fans or booster fans. If the intake end of the air pipes of a blowing fan is not placed well to the intake side of the main air current, the foul air from the heading may be recirculated to the face again and again. With an exhausting auxiliary fan, the end of the pipes is kept well to the return side of the main air current. See also: two-fan auxiliary ventilation recirculation of water The water used in a condenser or in a washery or other wet process is often repumped into the system by means of a circulating pump. The practice is economical in water and in reagent consumption and also reduces pollution of local streams. Water that is recirculated is clarified to reasonable purity. See also: washery water reclaiming a. Digging from stockpiles. Nichols, 1 b. Reprocessing previously rejected material. Nichols, 1 reclaiming conveyor a. Any of several types of conveyors used to reclaim bulk materials from storage. b. The conveyor which receives material from the reclaimer in a blending system. reclamation

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a. The recovery of coal or ore from a mine, or part of a mine, that has been abandoned because of fire, water, or other cause. b. Restoration of mined land to original contour, use, or condition. recleaner cell See: cleaner cell reclosing circuit breaker A circuit breaker that recloses automatically as soon as the demand for current becomes equal to or less than that for which the circuit breaker is set. Zern recommended exposure limit An 8-h or 10-h time-weighted average or ceiling of exposure to coal dust concentration; recommended by NIOSH and based on an evaluation of the health effects data. NIOSH recomposed granite a. An arkose consisting of consolidated feldspathic residue (produced by surface weathering of an underlying granitic rock) that has been so little reworked and so little decomposed that upon cementation the rock looks very much like the granite itself. It has a faint bedding, an unusual range of particle sizes (unlike the even-grained or porphyritic texture of true granite), and a greater percentage of quartz than is normal for granite. Syn: reconstructed granite b. A conglomerate that has been recrystallized by metamorphism into a rock that simulates granite, as in the Lake Superior region. CF: meta-arkose recomposed rock A rock produced in place by the cementation of the fragmental products of surface weathering; e.g. a recomposed granite. The term has been applied to a rock of intermediate character straddling an unconformable surface between the breccia of the lower formation and the conglomeratic base of the upper formation. AGI reconnaissance a. A general, exploratory examination or survey of the main features (or certain specific features) of a region, usually conducted as a preliminary to a more detailed survey; e.g. an engineering survey in preparing for triangulation of a region. It may be performed in the field or office, depending on the extent of information available. AGI b. A rapid geologic survey made to gain a broad, general knowledge of the geologic features of a region. AGI 2570

reconnaissance map A map incorporating the information obtained in a reconnaissance survey and data obtained from other sources. reconnaissance sampling See: pilot sampling reconnoiter To make a reconnaissance of; esp. to make a preliminary survey of an area for military or geologic purposes. AGI reconstructed amber See: pressed amber reconstructed granite See: recomposed granite reconstructed turquoise An imitation turquoise made of finely powdered ivory which is deposited in a solution of copper. Fay reconstruction The modernization of underground roadways, transport, ventilation systems, and the layout of mine workings. It may include modernization of shafts and winding and also the improvement of surface handling and cleaning or washing equipment. See also: mechanization reconstructive transformation An isochemical change in a crystal structure in which chemical bonds are broken and reformed, e.g., tridymite-quartz or diamond-graphite. CF: dilational transformation; displacive transformation; rotational transformation; phase transformation. record borehole See: record hole record hole 2571

The first borehole drilled in an area that is cored so that a detail record of the formations penetrated can be obtained. Also called test hole. See also: stratigraphic hole recording gage A gage which automatically records the level of water in a stream or tank, or velocity and pressure in a pipe. It is operated by a float or by a submerged air tank fitted with a rubber diaphragm. Hammond record table Heavy-duty shaking table used to treat relatively coarse sands. Shaking is by double-link eccentric motion, with longer and slower throw than with Wilfley type of table. Pryor, 3 recover a. To restore a mine or a part of a mine that has been damaged by explosion, fire, water, or other cause to a working condition. Fay b. See: recovery recoverable grade The true mill-head grade of an ore-stream in percent, ounces, or parts per million of a metal or mineral, less extractive metallurgical losses; the proportion of an ore material actually recovered. recovered sulfur Elemental sulfur produced from hydrogen sulfide obtained from sour natural gas, petroleum refinery gas, water gas, and other fuel gases. recovery a. The percentage of valuable constituent derived from an ore, or of coal from a coal seam; a measure of mining or extraction efficiency. AGI b. The ratio of the footage of core acquired from core drilling a specific length of borehole, expressed in percent. Long c. The carat weight of diamonds salvaged from a worn bit. Long recovery plant a. A plant designed for separating diamond particles from concentrate by various processes, usually including grease belts, jigs, electrostatic separators, and flotation. Also known as picking station. b. The processing facility where minerals are recovered. recreational mining 2572

Mining as an avocation rather than as a business. Barton recrystallization The formation, essentially in the solid state, of new crystalline mineral grains in a rock. The new grains are generally larger than the original grains, and may have the same or a different mineralogical composition. AGI recrystallized silicon carbide A refractory made of about 98% to 99% SiC. rectangular drainage pattern A drainage pattern in which the main streams and their tributaries display many rightangle bends and exhibit sections of approx. the same length; it is indicative of streams following prominent fault or joint systems that break the rocks into rectangular blocks. AGI rectangular shaft A shaft excavated to an oblong shape. The majority of shafts sunk in the Republic of South Africa before 1948 were rectangular and timber lined. The shape lends itself to equipping concurrently with sinking; it provides a convenient in-line hoisting arrangement and can easily be divided into separate compartments. However, in the 1950's and 1960's developments were towards the concrete lined circular shaft. See also: compartment Nelson rectification a. The process by which electric energy is transferred from an alternating-current circuit to a direct-current circuit. Coal Age, 1 b. The purification of a liquid by redistillation. CTD c. In electronics and signal processing, the transformation of a signal from an alternating positive and negative signal into an all-positive signal by taking its absolute value. rectifier Equipment used in mines to convert alternating current to direct current. rectifying device An elementary device consisting of one anode and its cathode that has the characteristic of conducting current effectively in only one direction. Coal Age, 1 2573

rectorite A clay mineral with regularly interstratified mica and smectite layers. Syn: allevardite recumbent fold An overturned fold, the axial surface of which is horizontal or nearly so. recuperator a. A continuous heat exchanger in which heat is conducted from the products of combustion to incoming air through flue walls. ASTM b. A system of thin-walled refractory ducts used for the purpose of transferring heat from a heated gas to colder air or gas. Harbison-Walker c. Preheating equipment for recovering sensible heat from hot spent gases from a furnace and using it for heating incoming charge or fuel gases; essentially, a low-pressure heat exchanger. Syn: regenerative heating Henderson recurrence horizon A layer of peat marking a sharp change in the character of the peat and resulting from a profound change in climate. Tomkeieff red antimony See: kermesite red arsenic See: realgar red beds Sedimentary strata composed largely of sandstone, siltstone, and shale, with locally thin units of conglomerate, limestone, or marl, that are predominantly red in color due to the presence of ferric oxide (hematite) usually coating individual grains; e.g. the Permian and Triassic sedimentary rocks of western United States, and the Old Red Sandstone facies of the European Devonian. AGI red cake The vanadium concentrate in a milling operation. Ballard red chalk Hematite mixed with clay. 2574

red clay A brown to red deep-sea deposit, which usually contains manganese nodules or a film of manganese. It is the finest divided clay suspension that is derived from the land and transported by ocean currents, accumulating far from land and at the greatest depths. It has a high proportion of volcanic material due to lesser dilution of this material owing to slowness of accumulation of the clay portion. The color is believed to be caused by oxidation. Syn: brown clay red cobalt See: erythrite red copper ore See: cuprite red copper oxide See: cuprite redd a. Eng. To clear away fallen stone or debris. Syn: rid b. Northumb. Overburden. CF: ridding c. Scot. To scour through, take down, or rip. Fay redd bing A pile of waste made of material brought direct from the mine, not waste from washery. Zern reddingite An orthorhombic mineral, Mn3 (PO4 )2 .3H2 O ; forms a series with phosphoferrite; pink; at Redding, CT. reddle Red ocher mixed with clay. Also spelled ruddle, raddle. reddleman A dealer in reddle or red chalk. red dog 2575

Material of a reddish color resulting from the combustion of coal shale and other mine waste in dumps on the surface. reddsman Scot. One who works at night cleaning up and repairing roadways, etc. red earth The characteristic soil of most tropical regions. It is leached, red, deep, and clayey. red glassy copper ore See: cuprite red-hard A term applied to some varieties of tool steels that will retain their hardness even when operating at a red heat. Newton, 1 red heart A harmless reddish core, sometimes found in fire clay refractories. red hematite A compact columnar variety of hematite with a brownish-red to iron-black color; so called to contrast it with limonite and turgite. Syn: ironstone clay redingtonite A monoclinic mineral, (Fe,Mg,Ni)(Cr,Al)2 (SO4 )4 .22H2 O ; halotrichite group; forms reddish-purple fibrous masses. Red I plate See: selenite plate red iron froth A variety of hematite. Fay red iron ore See: hematite 2576

red iron vitriol See: botryogen redistilled metal Metal from which the impurities, usually zinc and mercury, have been eliminated by selective distillation. red lead See: minium red lead ore See: crocoite redledgeite A tetragonal mineral, BaTi6 Cr2 O16 .H2 O ; cryptomelane group. Formerly called chromrutile. red lime mud A red mud to which lime, caustic soda, or quebracho, has been added. The pH is usually 12.0 to 13.0. red manganese Any reddish manganese mineral, i.e., rhodonite and rhodochrosite. Also called red manganese ore. red mercury Alleged to be a compound of mercury and antimony, and described in the press to be an ingredient of explosives or nuclear weapons manufacture or possibly a descriptive term employed to mask illicit trading activity involving controlled substances. SME, 1 red metal a. A copper matte containing about 48% copper. Fay b. Any one of several alloys used in the manufacture of silverware. Fay red mud 2577

a. A reddish-brown terrigenous deep-sea mud that accumulates on the sea floor in the neighborhood of deserts and off the mouths of great rivers; contains calcium carbonate up to 25%. Hunt b. A clay-water-base drilling fluid containing sufficient amounts of caustic soda and tannates to give a pronounced red appearance. The pH is usually 10.0 to 13.0. Brantly, 1 red ore Hematite ore. red orpiment See: realgar red oxide of copper See: cuprite red oxide of zinc See: zincite redox potential Oxidation-reduction potential. AGI redrill To reopen a borehole by redrilling after it has been cemented, caved, or lost because of junk in the hole. Also called drill out, drilled out. CF: overlap red roast In fluidization roasting, conversion of iron from sulfides to red oxide. Pryor, 3 redruthite Corn. Copper glance. See: chalcocite reds High explosive; used in mines. Bennett red schorl 2578

See: elbaite; rubellite; rutile. redsear In ironworking, to break or crack when red-hot, as iron under the hammer. Standard, 2 red silver A red silver sulfide; esp. pyrargyrite and proustite. Syn: red silver ore red silver ore See: red silver reduce a. To lower the oxidation state by adding electrons to a chemical species. b. In general, to treat metallurgically for the production of metal. Fay reduced iron Free iron in a fine state of division obtained by reducing ferric oxide by heating it in a current of hydrogen. Also called iron by hydrogen, iron powder, and spongy iron. Standard, 2; Fay reduced level Height above specified datum level of a surveyed point. Pryor, 3 reduced natural frequency The natural frequency of vibration of a foundation at an average ground pressure of unity is the reduced natural frequency divided by the square root of the ground pressure. This relationship has been established by Tschebotarioff. Hammond reducing agent a. A material that adds hydrogen to an element or compound. McGraw-Hill, 1 b. A material that adds an electron to an element or compound; i.e., decreases the positiveness of its valence. McGraw-Hill, 1 reducing atmosphere

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a. An atmosphere having a deficiency of oxygen. b. An atmosphere of hydrogen or other substance that readily provides electrons. c. Space from which air has been displaced by hydrogen, carbon monoxide, or other reducing gas. CTD reducing flame The blue part or inner cone of the flame produced by a blowpipe; characterized by an excess of hydrocarbon over oxygen so as to reduce mineral samples heated in it. See also: blowpiping CF: oxidizing flame reducing furnace A furnace in which ores are reduced from oxides, or metal is separated from other substances by a nonoxidizing heat or flame; usually a shaft furnace. Syn: reduction furnace reducing roast The reduction of metallic oxides, sulfides, or halides by heating in contact with carbon or other reducing agents. Newton, 1; Newton, 2 reduction a. Process of reducing a metal compound to the metal and separating it from the slag; sometimes applied to the smelting process. b. A reaction taking place at the cathode in electrolysis through transfer of electrons to the species being reduced. c. A decrease in positive valence, or an increase in negative valence by the gaining of electrons. A metallic oxide loses oxygen through the action of reducing gas, reducing its valence. CF: oxidation reduction cell A pot or tank in which either a water solution of a salt or a fused salt is reduced electrolytically to form free metals or other substances. ASM, 1 reduction factor The factor relating the allowable stress on a long column with that on a short column in order to prevent buckling. Hammond reduction furnace See: reducing furnace. reduction of area 2580

a. The difference between the cross-sectional area of a tension specimen at the section of rupture before loading and after rupture, expressed as a percentage of the original area. Roark b. Percentage decrease in cross-sectional area of bar or wire after rolling or drawing. Hammond reduction of levels The calculation of reduced levels from the staff readings recorded in a field book. Hammond reduction ratio In crushing, the ratio of the size of the largest feed particle to the smallest distance between the roll faces. As used frequently in the field, it is the ratio of the smallest aperture passing all of the feed to that passing all of the product. Another basis of expression is the ratio of the average size of feed to the average size of product. See also: overall reduction ratio; primary breaker. Taggart, 1 reduction roasting Lowering of oxygen content of ore by heating in reducing atmosphere. Pryor, 3 reduction smelting A pyrometallurgical process that produces an impure liquid metal and a liquid slag by heating a mixture of ore, flux, and reducing agent (usually coke). Newton, 1; Newton, 2 reduction to center The offset of a side auxiliary telescope requires a correction to observed horizontal angles, and the offset of a top auxiliary telescope requires a correction to observed vertical angles. The process of computing the correct angle from the observed angle is called reduction to center. Urquhart reduzate A sediment formed in a strongly reducing environment; e.g., coal, sedimentary sulfides, or sedimentary sulfur. AGI red vitriol See: bieberite; rose vitriol. Redwood number 2581

Viscosity, defined as rate of flow of oil from a Redwood viscometer. Pryor, 3 red zinc ore See: zincite red zinc oxide See: zincite reed a. Scot. Rift, or direction of easiest splitting. b. Weakness in a sedimentary rock parallel with the bedding. See also: cleat c. A reed filled with powder to act as a fuse. See also: spire reedmergnerite A triclinic mineral, NaBSi3 O8 ; feldspar group; occurs in small colorless prisms having wedge-shaped terminations; from oil wells in Duchesne County, UT. reef a. A ridgelike or moundlike structure, layered or massive, built by sedentary calcareous organisms, esp. corals, and consisting mostly of their remains; it is wave-resistant and stands above the surrounding sediment. Also, such a structure built in the geologic past and now enclosed in rock, commonly of differing lithology. AGI b. A narrow ridge or chain of rocks either at the water surface or too shallow to permit safe passage of a vessel. CF: bank c. A provincial term for a metalliferous mineral deposit, esp. gold bearing quartz. See also: reefing reef cap A deposit of fossil-reef material overlying or covering an island or mountain. AGI reef drive Aust. A cutting through the bedrock in alluvial mining for the purpose of seeking other underground, gold-bearing gravel channels. reefing Working auriferous reefs or veins. See: reef reef knoll 2582

See: bioherm reef limestone A limestone consisting of the remains of active reef-building organisms, such as corals, sponges, and bryozoans, and of sediment-binding organic constituents, such as calcareous algae. AGI reef wash Aust. Gold-bearing drift. reel A device used for hoisting that has largely been replaced by round ropes. A flat rope is used for the reel, which is wound on an overlapping spiral like a clock spring. The reel is like a conical drum that increases in diameter by the thickness of the rope at each turn. Reels are more suitable for hoisting from a single level than from different levels. Lewis reel boy In bituminous coal mining, one who works on an electric locomotive--power being transmitted through an electric cable wound around a reel on the locomotive--tending the cable to see that it is wound up and fed from the reel so that it will not pull or break from the point where electric current is supplied. Also called nipper. DOT reel locomotive A trolley locomotive with a wire rope reel for drawing cars out of rooms. The rope end is pulled by a runner into the face of the room, attached to a car, and reeled out by the locomotive. Zern reenforcing bar See: reinforcing bar Ree's torsion anemometer Consists of a thin square aluminum vane centrally suspended from a horizontal wire mounted in a vertical frame. The velocity of the air current is obtained from the measurement of the torque that has to be applied to the wire to bring the vane back to its vertical position. The instrument is mounted on a tripod, and the arrangement is such that the torsion can be applied, at a point 2 ft (0.6 m) away from the vane, by means of a shaft and bevel gearing. The instrument has been used to measure low air velocities in 2583

mines down to about 10 ft/min (3 m/min) and up to 180 ft/min (55 m/min). Syn: torsion anemometer reeve The orderly arrangement of a rope or cable on a system of pulleys or sheaves to assemble block-and-tackle equipment for handling heavy loads. Also called reeved. Long reeving Threading or placement of a working line. Nichols, 2 reference axes In structural petrology, three mutually perpendicular axes to which structural measurements are referred. a is the direction of tectonic transport, c is perpendicular to the plane along which differential movement takes place, and b lies in this plane but is perpendicular to a. reference electrode Hydrogen electrode used to determine electrode potentials of half-cells. Pryor, 3 reference level See: datum plane reference mark A selected distant point from which the bearings to other points can be measured at a survey station. Hammond reference plane See: datum plane reference seismometer In seismic prospecting, a detector placed to record successive shots under similar conditions, to permit overall time comparisons. Used in connection with the shooting of wells for velocity. AGI reference size 2584

Separation size, designated size, or control size used to define analyses of the products of a sizing operation. BS, 5 reference standard Taken or laid down as a standard for measuring, reckoning, or constructing. Webster 3rd reference station A station for which tidal constants have previously been determined and that is used as a standard for the comparison of simultaneous observations at a second station; also, a station for which independent daily predictions are given in the tide or current tables from which corresponding predictions are obtained for other stations by means of differences or factors. AGI referencing The process of measuring the horizontal (or slope) distances and directions from a survey station to nearby landmarks, reference marks, and other permanent objects that can be used in the recovery or relocation of the station. AGI refikite An orthorhombic mineral, C20 H32 O2 ; soft; white; in modern resins and lignite at Montorio, Abruzzes, Italy. Also spelled reficite. refine a. To free from impurities; to free from dross or alloy; to purify, as metals; to cleanse. Webster 3rd b. To treat cast iron in the refinery furnace so as to remove the silicon. Webster 3rd refined iron Wrought iron made by puddling pig iron. CTD refinery a. A facility in which relatively crude smelter products such as blister copper are refined and emerge as acceptably pure products. b. An electrolytic or chemical facility producing pure metals. refining The purification of crude metallic products. Fay 2585

refining heat A medium orange heat, about 655 degrees C, which imparts fineness of grain and toughness to steel that is raised to it and afterwards quenched. Webster 2nd refining temperature A temperature, usually just higher than the transformation range, employed in the heat treatment of steel to refine the structure, particularly the grain size. ASM, 1 reflected-light microscope A compound microscope in which plane-polarized light impinges upon a polished specimen, commonly opaque, the light being reflected back to the objective through a second polarizer, where mineral color and polarization colors are observed in the ocular. Syn: ore microscope See also: optical constant; polished section; microscopy. reflected-light microscopy See: ore microscopy reflected wave A (gaseous) pressure wave resulting from a direct wave striking an obstacle or an opposing surface and being reflected backwards. Rice, 2 reflection a. The return of a wave incident upon a surface to its original medium. CF: refraction; diffraction; total reflection. b. The bounding back of light or other rays as they strike a solid surface. Light incident on a polished planar surface reflects at an angle equal to the incident angle, the proportion of reflected light increasing with increasing refractive index; e.g., for normal incidence, 17% reflects from diamond (n=2.4), and 5% reflects from quartz (n=1.5). c. In seismic prospecting, the returned energy (in wave form) from a shot that has been reflected from a velocity discontinuity back to a detector; the indication on a record of reflected energy. d. Misnomer for X-ray diffraction peaks. Also spelled reflexion. reflection goniometer An instrument that measures angles between crystal faces by reflecting a beam of light from successive faces as the crystal is rotated. See also: contact goniometer reflection mechanism 2586

A rule stating that rock breaks from the surface inward toward the explosive rather than from the explosive charge outward. Syn: blasting reflection mechanism reflection method See: seismic reflection method reflection shooting A type of seismic survey based on measurement of the travel times of waves that originate from an artificially produced disturbance and are reflected back at near-vertical incidence from subsurface boundaries separating media of different elastic-wave velocities. CF: refraction shooting AGI reflection wave A wave that is propagated backward through the burned gas as the result of an explosion wave being completely or partly arrested against the closed extremity, or in a constricted portion of its path, as in a tube, gallery, etc. Fay reflectivity The ratio of radiant energy reflected by a body to that falling upon it. Strock, 2 refraction The deflection of a ray of light or of an energy wave (such as a seismic wave) due to its passage from one medium to another of differing density, which changes its velocity. CF: reflection; diffraction. AGI refraction method A seismic method of geophysical prospecting. See also: refraction shooting refraction shooting a. The detonation of heavy charges of explosive in comparatively shallow holes or pits. The effects may be measured over a wide area. The firing creates the shock waves in the seismic method of prospecting. Nelson b. A type of seismic survey based on the measurement of the travel times of seismic waves that have traveled nearly parallel to the surface of high-velocity layers, in order to map such layers. See also: isochrone lines refractive index See: index of refraction; dispersion. 2587

refractometer a. A combustible gases detector. See also: interference methanometer Nelson b. An instrument for measuring indices of refraction of transparent substances, both liquid and solid. CF: Abbe refractometer refractoriness The capacity of a material to resist high temperature. In the refractories industry, the pyrometric cone equivalent (PCE) is a comparative value used to determine the refractoriness of a material. Henderson refractory a. Said of an ore from which it is difficult or expensive to recover its valuable constituents. AGI b. Exceptionally resistant to heat. AGI c. A nonmetallic material suitable for use in high-temperature applications. AGI refractory bonding mortars High-temperature bonding mortars containing various materials and exhibiting various properties, but primarily intended for providing structural bond between refractory units in high-temperature industrial furnace construction. Henderson refractory brick a. A brick made from refractory material, such as fire clay, bauxite, diaspore, etc., used to withstand high temperatures. Refractory bricks are made in various sizes and shapes. b. A brick used as a lining for the interior of fireboxes in furnaces and boilers. Refractory brick is constructed so that it can withstand very high temperatures, but it is not a very good insulator. API, 1 refractory clay See: fireclay refractory lining A lining that has high refractory qualities and is therefore suitable for furnace linings and boiler foundations. It is made from a good-quality refractory ore, clay, fireclay, or gannister. Nelson refractory material

2588

A material able to withstand high temperatures and, therefore, used in such applications as lining furnaces. refractory ore Ore difficult to treat for recovery of the valuable substances. AGI refractory stone Consists of sandstone, quartzite, mica schist, soapstone, or other rock that will withstand a moderately high temperature without fusing, cracking, or disintegrating. It may be used in solid blocks or crushed and mixed with a binder to form bricks. USBM, 7 refractory ware Usually hollow ware, such as, saggers, pyrometer tubes, crucibles, etc.; also refractory brick and shapes. refresher training In mining, training given to all miners at least once a year consisting of 8 hours of instruction reviewing the essentials of new miner training. CF: new miner training; task training. Federal Mine Safety refrigerant A substance that will absorb heat while vaporizing and whose boiling point and other properties make it useful as a medium for refrigeration. Strock, 2 refrigeration a. In special application to mining, cooling of air before release in lowest levels of deep, hot mine; also, expansion of compressed air for the same purpose. b. The process of absorption of heat from one location and its transfer to and rejection at another place; arbitrarily expressed in units of (short) tons and is equal to the coil cooling load divided by 12,000; 1 st (0.9 t) of ice in melting in 24 h liberates heat at the rate of 200 Btu/min (211 kJ/min), or 12,000 Btu/h (1.27 MJ/h). Hartman, 1 refrigeration plant a. A surface plant to form the protective barrier of frozen ground in the freezing method of shaft sinking. The cooling agent used is ammonia which, in its gaseous state, is compressed to about 120 psi (827 kPa) when it passes to the top of the condensers, emerging at the bottom as liquid ammonia under pressure. It then passes through a regulator valve into the coolers where it immediately evaporates. The latent heat of 2589

evaporation is extracted from the brine circuit--the brine being passed through the coolers by the brine pumps. The ammonia gas passes back for re-use. The brine emerges from the coolers at a temperature of -4 degrees F (-21.7 degrees C) and is pumped down the boreholes to freeze the water around the shaft sinking. b. A surface plant to cool liquids. These liquids or ice are sent underground to cool the air current in heat exchangers. By this method, the air in deep mines is cooled considerably and the working environment is improved. See also: deep mining refuge chamber An airtight, fire-resistant room in a mine used as a refuge in emergencies by miners unable to reach the surface. MSHA, 4 refuge hole A place formed in the side of an underground haulageway in which a worker can take refuge during the passing of a train, or when shots are fired. Also called refuge stalls. See also: manhole refusal A condition arrived at when driving pipe, casing, piling, etc., when it cannot be driven to a greater depth or made to penetrate the ground a distance of more than 1 ft (30.5 cm) per 100 blows delivered by a drive hammer. Long refuse a. Waste material in the raw coal that has been removed in a cleaning or preparation plant. b. Notably used to describe colliery rejects; also called tailings. Pryor, 3 refuse conveyor An adaptation of a drag chain conveyor. refuse discharge pipes Pipes used on some washboxes instead of a refuse worm. BS, 5 refuse elevator See: reject elevator refuse extraction chamber That part of the washbox into which the refuse extractor discharges. BS, 5 2590

refuse extractor A device used in a washbox to remove the reject from the washing compartments, operated manually or automatically. BS, 5 refuse rotor A reject gate in the form of a rotary (or star) valve. BS, 5 refuse worm A screw conveyor fitted at the bottom of some washboxes to collect the fine reject which has passed through the apertures in the screen plate. BS, 5 regalian doctrine The old doctrine that all mineral wealth was the prerogative of the crown or the feudatory lord. The concession system, in which the state or the private owner has the right to grant concessions or leases to mine operators at discretion and subject to certain general restrictions, had its origin in this doctrine. Almost all mining countries of the world, except the United States, follow this system. Hoover regal jade See: Indian jade regenerated anhydrite Anhydrite produced by dehydration of gypsum that itself was generated by the hydration of anhydrite. regenerated dense medium Medium obtained from the medium recovery system and purified (wholly or partly) from contaminating fine coal and clay. BS, 5 regeneration a. In mineral leaching, reconstitution of barren leach solution after it has completed its chemical attack on mineral and its values have been removed. The regeneration of ion exchange resins and activated carbons by the removal of elements or compounds from extraction sites on the resins by special eluants. Pryor, 3 b. A reversing heat exchanger for preheating combustion air (and gaseous fuels) from waste heat of the exhaust gases. Van Vlack 2591

regenerative chambers Separate compartments connected with a furnace; they are arranged for preheating the gas and the air used for fuel. Mersereau, 2 regenerative furnace A furnace in which hot gases, usually waste combustion gases, pass through a set of chambers containing firebrick structures, to which the sensible heat is given up. The direction of hot-gas flow is diverted periodically to another set of chambers and cold incoming combustion gas or air is preheated in the hot chambers. regenerative heating See: recuperator regenerative principle Used in open-hearth furnaces to increase the furnace temperature by preheating the fuel gas and air previous to their combustion in the furnace. Newton, 1 regenerator checkers Brick used in furnace regenerators to recover heat from hot outgoing gases, and later to release this heat to cold air or gas entering the furnace; so called because of the checkerboard pattern in which the bricks are arranged. Harbison-Walker regime In hydraulics, the condition of a river with respect to the rate of its flow as measured by the volume of water passing different cross sections in a given time. Webster 3rd regional a. Extending over large areas in contradistinction to local or restricted areas. Fay b. In gravity prospecting, contributions to the observed anomalies due to density irregularities at much greater depths than those of the possible structures, the location of which was the purpose of the survey. The term is also employed in an analogous sense in magnetic prospecting. AGI regional anomaly a. The more localized departures in the Earth's field from the values that would be predicted if the field were to originate with a single magnet oriented along the magnetic axis. These have maximums as great as 10,000 gamma, which is about a third the total 2592

intensity at the equator, and extend over areas as large as a million square miles. The locations of such features do not change with time as do anomalies associated with secular variation. Dobrin b. The departure of a measured quantity from an expected or theoretical value on a scale larger than the most rapid spatial variations of the measured quantity; typically variations over tens to hundreds of kilometers. regional dip The nearly uniform inclination of strata over a wide area, generally at a low angle, as in the Atlantic and Gulf coastal plains and parts of the Midcontinent region. CF: homocline regional metamorphism A general term for metamorphism affecting an extensive region, as opposed to local or contact metamorphism. CF: dynamothermal metamorphism; local metamorphism. regional unconformity A surface of discontinuity in sedimentary rocks that extends throughout an extensive region. It may record a significant interruption in deposition, tectonics, or erosion of older strata. registered premises Premises registered with the local authority for the storage of not more than 60 lb (27.2 kg) of explosive. See also: licensed store; magazine. BS, 12 reglette A 12-in (0.3-m) scale divided into tenths and hundredths of a foot, used for accurate measurement in conjunction with a steel band that is graduated only in feet. See also: band chain regolith The layer or mantle of loose incoherent rock material, of whatever origin, that nearly everywhere underlies the surface of the land and rests on bedrock. It comprises rock waste of all sorts: volcanic ash, glacial drift, alluvium, windblown deposits, organic accumulations, and soils. Syn: mantle rock regular lay Wire rope or cable in which the individual wire or fibers forming a strand are twisted in a direction opposite to the twist of the strands. Also called ordinary lay. Syn: standard lay 2593

regular-lay left lay See: left regular lay regular-lay right lay See: right regular lay regular polygon A polygon having equal sides, and the angles between these sides are equal. Jones, 2 regular sampling The sampling of the same coal or coke received regularly at a given point. There are two forms of regular sampling, namely, continuous sampling and intermittent sampling. BS, 2 regular ventilating circuit All places in a mine through which there is a positive flow of air without the aid of a blower fan or of ventilation tubing. regulated feed In contrast with choke feed, feed that is throttled back to a value below the full capacity of the crusher. South Australia regulated split In mine ventilation, a split where it is necessary to control the volumes in certain lowresistance splits to cause air to flow into the splits of high resistance. regulating gate A gate used to vary size of opening so as to control the flow of material through the opening. See also: bin gate regulator a. A ventilating device, such as an opening in a wall or door; usually placed at the return of a split of air to govern the amount of air entering that portion of a mine. Kentucky b. A device for creating shock loss to restrict passage of air through an airway. Regulators are usually set in doors as adjustable, sliding partitions that can be varied to the desired opening. In their simplest form, for temporary service in an untraveled part of a mine, 2594

regulators consist of doors propped partially open. Where possible, regulators are located on the exhaust side of a split (in a return airway) to minimize interference with traffic. See also: ventilation Syn: ventilation regulator regulator door See: scale door regulus Impure metal produced during smelting of ores or concentrates. Pryor, 3 reheater An apparatus for reheating a substance, as ingot steel, that has cooled or partly cooled during some process. Standard, 2 reheater load The amount of sensible heat in w (British thermal units per hour), restored to the air in reheating. Hartman, 2 reheating furnace The furnace in which metal ingots, billets, blooms, etc., are heated to bring them to the temperature required for hot-working. CTD Rehisshakenhobel A plow developed from the Anbauhobel machine and designed for cutting thin coal seams. The plow drives, instead of being on the face side of the conveyor, are on the waste side and the plow chains run in two tubes along the waste side of the conveyor chutes. See also: Anbauhobel Nelson reinerite An orthorhombic mineral, Zn3 (AsO3 )2 ; blue to green; at Tsumeb, Namibia. (Not renierite.) reinforcing bar a. The basic material used to form grouted roof belts. b. Iron or steel bars of various cross-sectional shapes used to strengthen concrete. c. See: rebar; reenforcing bar. reinforcing steel 2595

Steel bars of various shapes used in concrete construction to give added strength. Crispin reinite A pseudomorph, FeWO4 ; after scheelite(?). reiteration In surveying, angular measurement made first with vertical circle of theodolite to right of sighting telescope, then repeated after transiting this through 180 degrees . Also called face right, face left observation. Pryor, 3 reject a. The material extracted from the feed during cleaning for retreatment or discard. BS, 5 b. The stone or dirt discarded from a coal preparation plant, washery, or other process; has no value. See also: middlings; refuse; residue; tailings. Nelson reject elevator An elevator for removing and draining the reject from a washing appliance. Syn: refuse elevator reject gate The mechanism of the refuse extractor that may be manually or automatically operated to control the rate of removal of reject from the washbox. BS, 5 rejuvenation The renewal of any geologic process, such as the revival of a stream's erosive activity or the reactivation of a fissure. relative age The geologic age of a fossil organism, rock, geologic feature, or event, defined relative to other organisms, rocks, features, or events rather than in terms of years. CF: absolute age relative biological effectiveness The relative effectiveness of a given kind of ionizing radiation in producing a biological response as compared with 250,000 electron-volt gamma rays. Abbrev., rbe. Lyman relative bulk strength 2596

A measure of the energy available per unit volume of explosive as compared to an equal volume of ANFO at a density of 0.81 g/cm3 ; it is calculated by dividing the bulk strength of an explosive by the bulk strength of ANFO and multiplying by 100. See also: absolute bulk strength relative compaction a. For soil compaction, two types of tests are necessary: (1) determining the dry density of the soil after a standard amount of compaction has been applied, and (2) measuring the density of the soil in the field. The state of compaction is expressed as the relative compaction, and is the percentage ratio of the field density to the maximum density as determined by standard compaction. The percentages of relative compaction are high, since the initial relative compaction is about 80%. Nelson b. The dry density of a soil in situ divided by the maximum dry density of the soil as established by the Proctor compaction test or any other standard test. See also: loose ground relative consistency The ratio of the liquid limit minus the natural water content to the plasticity index. ASCE relative density a. The relative density or specific gravity of a substance denotes the number of times the substance is heavier or lighter than water (for the same volume). Relative density and specific gravity mean the same thing. Morris b. The ratio of the difference between the void ratio of a cohesionless soil in the loosest state and any given void ratio to the difference between its void ratios in the loosest and in the densest states. ASCE relative humidity The ratio, expressed as a percentage, of the amount of water vapor in a given volume of air to the amount that would be present if the air were saturated at the same temperature. CF: absolute humidity; specific humidity. AGI relative movement In fault descriptions, the displacement of one block relative to the other, rather than to some fixed point or plane of reference. AGI relative roughness The dimensionless ratio Epsilon /d (where Epsilon is the average height of the surface irregularities and d is the diameter of the pipe) is termed the relative roughness. The physical interpretation of this functional equation is that the friction factors of pipes are the same if their flow patterns in every detail are geometrically and dynamically similar. 2597

The term Epsilon indicates the height of the irregularity above the boundary surface only; hence it is apparent that, dependent upon the thickness of the boundary layer adjacent to the surface, the projection can either lie submerged within the boundary layer or else project outside it. Roberts, 1 relative time Geologic time determined by the placing of events in a chronologic order of occurrence; esp., time as determined by organic evolution or superposition. CF: absolute time relative variogram A variogram in which the ordinary variogram value for each lag has been divided by the square of the mean of the sample values used in computing the lag. This is sometimes useful when a "proportional effect" is present; i.e., when areas of higher than average concentration also have higher than average variance. When relative variogram models are used in kriging, the resulting kriging standard deviations represent decimal fractions of the estimated values. relative weight strength This is a measure of the energy available per weight of explosive as compared to an equal weight of ANFO. It is calculated by dividing the absolute weight strength (AWS) of the explosive by the AWS of ANFO and multiplying by 100. See also: absolute weight strength relaxation a. In experimental structural geology, the release of applied stress with time, due to any of various creep processes. AGI b. In an elastic medium, the decrease of elastic restoring force under applied stress, resulting in permanent deformation. AGI c. Relief of stress by creep. Some types of tests are designed to provide diminution of stress by relaxation at constant strain, as frequently occurs in service. ASM, 1 d. The decrease of load support and of internal stress because of plastic strain at constant deformation. AGI relay A device, operated by an electric current, and causing by its operation abrupt changes in an electrical circuit (making or breaking the circuit, changing of the circuit connections, or variation in the circuit characteristics). NCB relay haulage Single-track, high-speed mine haulage from one relay station to another. Each operator has an exclusive track section between relay stations and can run at full speed since no 2598

other haulage equipment is operating on the section. Side track at each relay station permits the operator to pick up or drop off loads or empties, then make the return run. Also called intermediate haulage. See also: haulage relay motorman See: gathering motorman release analysis A procedure employed to determine the best results possible in cleaning a coal by froth flotation. BS, 5 released mineral A mineral formed during the crystallization of a magma as a consequence of an earlier phase failing to react with the liquid. Thus the failure of earlier formed olivine to react with the liquid portion of a magma to form pyroxene may result in the enrichment of the liquid in silica, which finally crystallizes as quartz, the released mineral. AGI release fracture A fracture developed as a consequence of the relief of stress in one particular direction. The term is generally applied to a fracture formed when the maximum principal stress decreases sufficiently that it becomes the minimum principal stress; the fracture is an extension fracture oriented perpendicular to the then-minimum principal-stress direction. AGI release mesh a. In liberation of specific mineral from its ore by comminution, the optimum grind. Pryor, 3 b. Specified mesh-of-grind for best conditions for treatment to recover a specific mineral from the ore. Pryor, 4 reliability of method In geochemical prospecting, refers to the probability of obtaining and recognizing indications of an orebody or mineralized district by the method being used. Reliability depends not only on whether a readily detectable target exists and how effective the exploration method is in locating it, but also on the extent to which the anomaly is specif. related to ore and the extent to which it is possible that non-significant anomalies may confuse the interpretation. Hawkes, 2 relic 2599

A landform that has survived decay or disintegration, such as an erosion remnant; or one that has been left behind after the disappearance of the greater part of its substance such as a remnant island. The term is sometimes used adjectivally as a synonym of relict, but this usage is not recommended. AGI relict Pertaining to a mineral, structure, or feature of an earlier rock that has persisted in a later rock in spite of processes tending to destroy it. Also, such a mineral, structure, or other feature. AGI reliction The slow and gradual withdrawal of the water in the sea, a lake, or a stream, leaving the former bottom as permanently exposed and uncovered dry land; it does not include seasonal fluctuations in water levels. Legally, the added land belongs to the owner of the adjacent land against which it abuts. Also, the land left uncovered by reliction. AGI relict texture In mineral deposits, an original texture that remains after partial or total replacement. AGI relief a. A term used loosely for the physical shape, configuration, or general unevenness of a part of the Earth's surface, considered with reference to variations of height and slope or to irregularities of the land surface; the elevations or differences in elevation, considered collectively, of a land surface. CF: topography b. The vertical difference in elevation between the hilltops or mountain summits and the lowlands or valleys of a given region. A region showing a great variation in elevation has high relief, and one showing little variation has low relief. AGI c. The range of values over an anomaly or within an area; e.g., the gravity relief for the magnitude of a gravity anomaly. AGI d. An apparently rough surface of a crystal section under a microscope. High relief indicates a great difference in index of refraction between the crystal and its mounting medium. The relief is positive if the refractive index of the mineral is greater than that of the medium, and negative in the reverse case. Syn: shagreen e. The result of the removal of tool material behind or adjacent to the cutting edge to provide clearance and prevent rubbing (heel drag). ASM, 1 relief feature See: landform relief holes 2600

a. Boreholes that are loaded and fired for the purpose of relieving or removing part of the burden of the charge to be fired in the main blast. b. Holes drilled closely along a line, that are not loaded, and that serve to weaken the rock so that it will break along that line. Syn: trim holes c. Singular. A port or passageway through which the core, as it advances into the inner tube of a double-tube core barrel, forces water out of the inner tube to the outside of the barrel through the innertube head. Long d. Singular. A borehole drilled ahead of underground openings to tap and drain a water-bearing formation. Also called cover hole; pilot hole. Long relief limonite Indigenous limonite that is porous and cavernous in texture, commonly botryoidal after chalcocite. CF: indigenous limonite relief map A map representing topographic relief of an area by contour lines, hachures, hill shading, coloring, or similar graphic means. relief valve A valve that will allow air or fluid to escape if its pressure becomes higher than the valve setting. Also called pressure relief valve. Nichols, 1 relief well A borehole that is drilled at the toe of an earth dam as a relief for any high water pressure caused by the weight of the dam. Hammond relieving cut In a round of shots planned for sequential firing when shaft sinking or tunneling, holes fired after cut holes and before lifters and slippers. Pryor, 3 relieving platform A loading deck for lorries on the land side of a retaining wall contructed, for example, as a jetty of steel sheet piling, the relieving platform being supported as a rule partly by the wall and partly by bearing piles. See also: surcharge relieving shot A shot fired to dislodge or expose a misfire. BS, 12 relighter flame safety lamp 2601

A locked spirit-burning lamp fitted with an internal relighting device. BS, 8 relighting station A place in a mine at which safety lamps can be relighted under controlled conditions. BS, 13 reluctance Magnetic quality analogous to resistance in the flow of electric current. Pryor, 3 remanence Residual magnetism in a ferromagnetic substance (its hysteresis) after removal of an external magnetizing force. Pryor, 3 remanent magnetization a. Part of the magnetization of a body that does not disappear when the external magnetic field disappears. Schieferdecker b. That component of a rock's magnetization that has a fixed direction relative to the rock and is independent of moderate, applied magnetic fields such as the Earth's magnetic field. CF: induced magnetization See also: hysteresis remnant When a block of ground is stoped in such a way that at some time its remainder is surrounded on all sides by stoped ground, that remainder is termed a remnant. Spalding remolded soil Soil that has had its natural structure modified by manipulation. ASCE remolding Disturbance of the interval structure of clay or silt; when remolded, such material will lack shearing strength and gain compressibility. In consequence, driven piles are not recommended in certain clays. See also: thixotropic fluid remolding index The ratio of the modulus of deformation of a soil in the undisturbed state to the modulus of deformation of the soil in the remolded state. ASCE remolding sensitivity 2602

The ratio of the unconfined compressive strength of an undisturbed specimen of soil to the unconfined compressive strength of a specimen of the same soil after remolding at unaltered water content. Also called sensitivity ratio. ASCE remolinite See: atacamite remote control a. The control of plant operation by personnel or computers housed under conditions that can be remote, safe, and convenient. This is a feature of both electrical and electronic automatic control. In the control room, various plants can be started up by pushbutton and the governing conditions can be set. Instrumentation records all relevant data; it also gives warning of unsafe conditions and shuts down the plant if no correction is made. Changeover switches can introduce different operations and sequences in the working of the plant. Indicating lights can show what plant is working and the progress made. Fault indication can show the reason in the event of a shutdown. Also called centralized control. Nelson b. A term applied to a switch, circuit breaker, starter, or similar apparatus, to denote that its operation can be controlled manually, from a distance, by electrical or other means. BS, 13 remote control support system A self-advancing support system in which the chocks and/or props are advanced and reset on a longwall face from a point in the gate road leading to the face. Hydraulic pressure and valves are commonly employed and the system is largely in the experimental stage. See also: pushbutton coal mining remote sensing A branch of geophysics that acquires and interprets airborne or satellite images of the surface using infrared and visible wavelengths of light. renardite An orthorhombic mineral, Pb(UO2 )4 (PO4 )2 (OH)4 .7H2 O that may be the mineral dewindtite; at Kasolo, Zaire. rending The breaking of coal into lumps with a minimum of smalls. The relative slowness of low explosives makes them suitable for rending coal since they lack the greater shattering power of high explosives. Mason 2603

rendrock A dynamite used in blasting and consisting of nitroglycerin, potassium nitrate, wood pulp, and paraffin or pitch. Webster 3rd renierite A tetragonal mineral, (Cu,Zn)11 (Ge,As)2 Fe4 S16 ; pseudocubic; a possible source of germanium. (Not reinerite.) reniform Kidney-shaped. Said of a crystal structure in which radiating crystals terminate in rounded masses; also said of mineral deposits having a surface of rounded, kidneylike shapes. CF: colloform; colloid minerals; botryoidal. AGI Renn-Walz process A method of reclaiming iron and other metals from the waste materials produced in the smelting of zinc and lead ores. The process differs from the Krupp-Renn method in that it is a volatilization process for recovering molten metals in oxide form. The metal vapors are oxidized by excess air and carried off in the flue gases from which they are subsequently filtered. Osborne rensselaerite A compact fibrous variety of talc pseudomorphous after pyroxene; harder than talc; polishes well; made into ornamental objects; in northern New York and Canada. rent and royalty a. The amount paid by a coal mining operator to the owner of the coal for each ton of coal mined and usually expressed in cents per ton. b. In mining leases, words used interchangeably to convey the same meaning. Ricketts reopening sealed area There are four methods used in reopening sealed-off areas in a mine: (1) the direct method in which the stoppings are breached and air is circulated around the district without previous inspection by a rescue team; (2) the prior-inspection method in which prior inspection of the whole district by a rescue team is followed by circulation of air around the district; (3) the stage method in which the ventilation is restored and the enclosed gases are removed in successive stages; and (4) the partial-reopening method which is adopted when it is required to recover part of a district but leave the remainder sealed off. Sinclair, 1 2604

repairman A worker whose duty it is to repair tracks, doors, brattices, or to reset timbers, etc., under the direction of a foreman. Also called repairer. Zern repeated twinning Crystal twinning involving more than two individuals. Syn: multiple twin cyclic twinning. replaceable hydrogen Hydrogen atoms in acid molecule that can be replaced by those of metal. Pryor, 3 replaceable insert Diamond inset plates and other geometric forms fastened to and/or supported by the bit blank by brazing or mechanical locking so that in drilling they may be replaced when diamond wear exceeds a specified amount. Long replaceable pilot A central interchangeable pluglike portion of a noncoring bit protruding or leading the outside portion of such bits. See also: pilot Long replacement a. Change in composition of a mineral or mineral aggregate, presumably accomplished by diffusion of new material in and old material out without breakdown of the solid state. AGI b. A process of fossilization involving substitution of inorganic matter for the original organic constituents of an organism. AGI replacement bit See: reset bit replacement deposit A mineral deposit that has been formed by deposition from mineral solutions taking the place of some earlier, different substance. replacing switch A device consisting of a united pair of iron plates hinged to shoes fitting over the rails to replace, on the track, derailed railway rolling stock. Also used for mine cars. Fay 2605

replica A filling of mineral material deposited by percolating ground waters in external molds, thus reproducing the original exterior of the fossil shell or other object, with its exact size and shape. AGI replicate sampling Taking each sample in a number of subsamples by putting increments in turn into different containers, in order to estimate the sampling accuracy. The same total weight of sample is collected whether or not replicate sampling is employed. BS, 2 repose angle The angle between the horizontal and the surface slope of any pile of material formed by free fall of the material. representation work Assessment work on a mining claim. representative fraction The scale of a map, expressed in the form of a numerical fraction that relates linear distances on the map to the corresponding actual distances on the ground, measured in the same units (centimeters, inches, feet); e.g., 1/24,000 indicates that one unit on the map represents 24,000 equivalent units on the ground. Abbrev: RF. AGI representative sample In testing or valuation of a mineral deposit, samples large enough and average in composition as to be considered representative of a specified volume of the surrounding orebody. Blended large samples from different exposures are not necessarily representative, since the mineral structure may have varied so as to introduce special problems from area to area in treatment. Pryor, 3 rerailer A small lightweight device, used in pairs that straddle and are locked to each of the rails to retrack railroad cars and locomotives. Of Y-shaped design, they permit both wheels to be retracked from either or both sides of the rail at the same time. As the car is pulled across the device, the derailed wheels are channeled back onto the tracks. Also called retracker. See also: frog rescue 2606

To move live workers or dead bodies from a mine after a mine disaster. Sometimes called recover. The latter applies esp. to putting the mine in shape for operation again. rescue apparatus A name applied to certain types of apparatus worn by workers, permitting them to work in noxious or irrespirable atmospheres such as obtained during mine fires, following mine explosions, as a result of accidents in ammonia plants, from smelter fumes, etc. Oxygen compressed in a cylinder, a regenerating substance to purify the breathed air, and a closed system constitute the general principle of the apparatus. See also: mine rescue apparatus rescue-car See: mine rescue car rescue station Mine chamber equipped with rescue gear, including oxygen apparatus, and manned by trained rescue workers. Pryor, 3 rescue team A team of workers, from five to eight strong, trained in the use of breathing apparatus and in rescue operations after colliery explosions or mine fires. The team trains every week or so at a rescue station. Nelson research Word often misused. Two broad meanings are reexamination of previously accepted data in the light of current expansion of basic knowledge; and search in reality, specific to an entirely novel concept and calling for development of new approaches. Wrongly defined when descriptive of original rehash. Pryor, 3 resection a. A method in surveying by which the horizontal position of an occupied point is determined by drawing lines from the point to two or more points of known position. Syn: intersection b. A method of determining a plane-table position by orienting along a previously drawn foresight line and drawing one or more rays through the foresight from previously located stations. AGI resequent fault-line scarp

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A fault-line scarp in which the structurally downthrown block is also topographically lower than the upthrown block. CF: obsequent fault-line scarp reserve a. The quantity of mineral that is calculated to lie within given boundaries. It is described as total (or gross), workable, or probable working, depending on the application of certain arbitrary limits in respect of deposit thickness, depth, quality, geological conditions, and contemporary economic factors. Proved, probable, and possible reserves are other terms used in general mining practice. BS, 7 b. Sampled ore, developed, blocked out, or exposed on not less than three sides. See also: development sampling; ore reserve; probable ore; workable. CTD c. The amount of payable ore, developed and ready for extraction, or blocked out ahead of immediate requirements. Weed, 2 reserve base That part of an identified resource that meets specified minimum physical and chemical criteria related to current mining and production practices, including those for grade, quality, thickness, and depth. The reserve base is the in-place demonstrated (measured plus indicated) resource from which reserves are estimated. It may encompass those parts of the resources that have a reasonable potential for becoming economically available within planning horizons beyond those that assume proven technology and current economics. The reserve base includes those resources that are currently economic (reserves), marginally economic (marginal reserves), and some of those that are currently subeconomic (subeconomic resources). The term geologic reserve has been applied by others generally to the reserve-base category, but it also may include the inferred-reserve-base category; geologic reserve is not part of this classification system. USGS, 2 reserved coal Coal reserved from lease, as coal under buildings. reserved lands Defined by the U.S. Department of the Interior as "federal lands which are dedicated or set aside for a specific public purpose or program and which are, therefore, generally not subject to disposition under the operation of all the public land laws." SME, 1 reserved mineral Economic minerals that are not the property of the landowner but belong to the State. The State confers the right to prospect for and to mine these minerals on any one who applies for this right on the form prescribed and at the competent mining office. Such minerals as coal and iron ores are included in this group. CF: unreserved mineral 2608

reserves a. An estimate within specified accuracy limits of the valuable metal or mineral content of known deposits that may be produced under current economic conditions and with present technology. Shanz b. That part of the reserve base that could be economically extracted or produced at the time of determination. The term reserves need not signify that extraction facilities are in place and operative. Reserves include only recoverable materials; thus, terms such as extractable reserves and recoverable reserves are redundant and are not a part of this classification system. Syn: mineral reserves See also: measured resources reset action (nonstandard) In flotation, the component of control action in which the final control element is moved at a speed proportional to the extent of proportional position action. This term applies only to a multiple action including proportional position action. Fuerstenau reset bit A bit made by reusing the sound diamonds salvaged from a used drill bit and setting them in the crown attached to a new bit blank. Some new diamonds usually are added to those salvaged, since generally not all of the salvaged or recovered stones are reusable. Syn: replacement bit Long resettable A salvaged diamond or used diamonds in good condition; hence, diamonds that can be used again by being reset in another tool or bit. Also called usable diamond; usables; usable stone. Long resetting a. The act or process of producing a reset bit. See also: reset bit Long b. To rerun a casing string into a borehole by placing its bottom end at a lower point in the hole. Long residual a. Characteristic of, pertaining to, or consisting of residuum; remaining essentially in place after all but the least soluble constituents have been removed. b. Standing, as a remnant of a formerly greater mass of rock or area of land, above a surrounding area that has been generally planed; said of some rocks, hills, mesas, and groups of such features. residual arkose See: grus 2609

residual boulder A boulder of local origin produced by weathering and standing in locally derived soil or grus. residual clay Clay material formed in place by the weathering of rock, derived either from the chemical decay of feldspar and other rock minerals or from the removal of nonclaymineral constituents by solution from a clay-bearing rock (such as an argillaceous limestone); a soil or a product of the soil-forming processes. CF: primary clay; secondary clay. AGI residual element An element present in an alloy or other material in small quantities after some type of treatment, but not added intentionally. ASM, 1 residual errors The differences between measured values and the most probable value. Seelye, 2 residual field a. See: residual magnetic field b. The field remaining after subtraction of an average or background field (e.g., gravity, magnetic). residual gravity In gravity prospecting, the portion of a gravity effect remaining after removal of some type of regional variation; usually the relatively small or local anomaly components of the total or observed gravity field. AGI residual liquid A late-stage magmatic fluid. Syn: rest magma residual magnetic field a. The magnetic field that remains in a part after the magnetizing force is removed. ASM, 1 b. See: residual field residual magnetism

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a. In magnetic prospecting, the portion of a magnetic effect remaining after removal of some type of regional effect; usually the relatively small or local anomaly components of the total or observed magnetic field. AGI b. The magnetism remaining in a substance after the magnetizing force has been removed. See also: remanence residual minerals The rock-forming minerals that are either stable in the surface environment or unstable but react so slowly that they are not appreciably broken down. Hawkes, 1 residual oil a. The amount of liquid petroleum remaining in a formation at the end of a specified production process. AGI b. Liquid or semi-liquid products obtained as residues from the distillation of petroleum. They contain the asphaltic hydrocarbons. Residual oils are also known as asphaltum oil, liquid asphalt, black oil, petroleum tailings, and residuum. CCD, 2 residual ore deposit An accumulation of valuable minerals, formed by the natural removal of undesired constituents of rocks or conversion of useless to useful components. residual placer See: residual ore deposit residuals The elements ordinarily present in steel in small quantities without definite intent on the part of the steel maker. Osborne residual stress The stress that exists in an elastic solid body in the absence of, or in addition to, stresses caused by an external load. Such residual stress may be due to: (1) deformation, caused by cold-working, as in drawing or stamping; (2) change in the specific volume due to thermal expansion, a phase change, or magnetostriction; (3) by the joining together of structural parts by force, such as welding. Hammond residue a. The waste or final product from a hydrometallurgical plant. Fay b. S. Afr. The amount of valuable matter remaining in ore after treatment, in percent or pennyweights per ton. Beerman c. As applied to proximate analysis of coke, a calculated figure obtained by 2611

subtracting the sum of the percentages of moisture in the analysis sample, volatile matter, and ash from 100. BS, 1 d. That which remains after a part has been separated or otherwise treated. e. See: rock fracture residuite a. The constituent petrological unit or maceral occurring as characteristic unresolvable granular and translucent groundmass in clarain. AGI b. Same as residuum. Tomkeieff residuum a. Weathered material, including the soil, down to fresh, unweathered rock. Legrand b. Material resulting from the decomposition of rocks in place and consisting of the nearly insoluble material left after all the more readily soluble constituents of the rocks have been removed. c. The structureless groundmass of microscopically unresolvable constituents, consisting of particles of one to two microns or less, usually opaque, and of a dark color. It is the same as the lower range of fine micrinite. See also: residue resilience The ability of a material to store the energy of elastic strain. This ability is measured in terms of energy per unit volume. AGI resilient couplings The resilient type of coupling has many designs but essentially has torsional response to application or variation of the transmitted load. For the all-metal types, the resilient element may be in the form of laminated spring packs or a cylindrical grid member, connecting the driver and driven hubs. Resilience damps shock loads and also provides means of keeping gear teeth in contact, compensating for small errors in gear cutting. Other types use rubber or rubberlike material that may be in the form of a spider, segmental blocks, a number of balls, or a molded disk with metal inserts, providing the connection between the driver and driven hubs. Pit and Quarry resiliometer A device for testing resilience. Standard, 2 resin a. One of various hard, brittle, transparent or translucent solids formed esp. from plant secretions and obtained as exudates of recent or fossil origin, such as conifers and certain tropical trees, by condensation of fluids on loss of volatile oils. Resins are yellowish to brown with resinous luster; fusible and flammable; soluble in ether and other organic solvents, but not in water; and represent a complex mixture of terpenes, resin alcohols, 2612

and resin acids and their esters. CF: amber; fossil resin. See also: mineral resin b. A synthetic addition or condensation polymerization substance or natural substance of high molecular weight, which under heat, pressure, or chemical treatment becomes moldable. See also: bead; beads. Jessop resin-anchored bolts A passive roof-bolting technique in which a rebar-type bolt is anchored in resin. A twopart resin cartridge is placed at the back of a hole and is mixed as the bolt is inserted and rotated. The bolt is forced tight against the roof until the resin sets. resin-in-pulp An ion exchange process applied in acid-leach slurry from which abrasive particles of sand have been removed. Abbrev., R.I.P. Pryor, 3 resin-in-pulp (RIP) process The method in which pulp is classified to remove the sands, and the resin adsorbs the metal directly from the slime pulp without the necessity of thickening or filtering. It is esp. adapted for ores that do not settle readily, and where thickening and filtration are difficult. Newton, 1 resinite A maceral of coal within the exinite group, consisting of resinous compounds, often in elliptical or spindle-shaped bodies representing cell-filling matter or resin rodlets. CF: cutinite; sporinite. AGI resinite coal This coal consists of more than 50% of small resin bodies embedded in gelito-collinite, fusinito-collinite, or in collinite of fusinitic nature. The resin bodies differ in shape and may be angular, spheroidal, or lenticular. Varying in size, they may be visible to the unaided eye in a hand specimen of coal or only distinguishable under the microscope. Resinite coal may also contain small quantities of microspores, fine fragments of fusinized tissue, and, not infrequently, broad streaks of vitrinite. Hand specimens of resinite coal are matt or semimatt and in coals of low rank are brown or brownish-black. On fractures perpendicular to the bedding, the resin bodies appear rounded, black, and lustrous; in the bedding planes themselves they frequently appear as matt rodlets. Resinite coals frequently are high in ash. IHCP resin jack See: sphalerite 2613

resinoid A coal constituent similar to material derived from resin. AGI resinous a. Resembling resin, as opal, and some yellow varieties of sphalerite. Fay b. The luster on fractured surfaces of minerals, e.g., opal, sulfur, amber, and sphalerite, and rocks, e.g., pitchstone. CF: vitreous resinous coal Coal in which the attritus may contain a large proportion of resinous matter. Coals of this type are found more often among the younger coals. AGI resin rodlets A fossil resinous secretion that may be isolated from coal. It was presumably deposited in a resin duct by a secretory epithelium. AGI resin tin See: cassiterite resistance a. When an air current flows through a mine it meets with frictional resistance from the roof, sides, and floor. The amount of this resistance depends upon the extent and nature of the rubbing surface, the area of the airways, and the velocity of the air. See also: Atkinson b. In flotation, a property opposing movement of material or flow of energy, and involving loss of potential (voltage, temperature, pressure, and level). Fuerstenau c. The property of an electrical circuit that opposes the flow of a current and is measured in ohms. Syn: thermal resistance resistance methanometer A version of the catalytic methanometer with the addition of improved detector elements. Platinum may be used as the filament that both heats the detecting element and acts simultaneously as a resistance type thermometer. Gas is drawn through the instrument by a rubber suction bulb, and the filaments are heated from a dry battery of the mercury type contained in the apparatus. Readings of methane concentration can be taken on the built-in electrical meter. Nelson resistance of detonator 2614

As applied to electric blasting caps, the total resistance of the leg wires and the bridge wire. Fraenkel resistance strain gage See: electrical resistance strain gage resistance to blasting Specific value of the resistance of the rock to the explosive force, determined by trial blasting. It is a function of maximum burden, hole depth, quantity of explosive (degree of packing), and throw. Fraenkel resistivity a. Resistance, R, of a block of specified material in terms of units of length 1 and cross section a. Unit volume is 1 cm3 of the material concerned, and the resistivity measurement is made during electrical prospecting. Specific resistance = (Ra) / 1. Pryor, 3 b. The electrical resistance offered to the passage of a current. Usually expressed in ohm meters, which is the electrical resistance of a column of fluid 1 m long and 1 m2 in cross section. Brantly, 1 c. The opposite of conductivity of an electrical current passing through fluid-bearing rock formations. Wheeler, R.R. d. The electrical resistance between opposite faces of a 1-cm cube of a given substance. The unit of resistivity is ohm/centimeter. Hy e. The reciprocal of conductivity. Syn: thermal resistivity Strock, 2 resistivity method Any electrical exploration method in which current is introduced into the ground by two contact electrodes and potential differences are measured between two or more other electrodes. AGI resistivity profile a. A geophysical survey using the resistivity method. An assembly of electrodes spaced at a constant distance is moved along profiles, resulting in lateral variations in resistivity being shown. In favorable terrain, the test shows the existence of faults that have thrown strata of different resistivity against each other; similar relationships result in the detection of an anticline, a syncline, or an underground channel. Nelson b. A survey by the resistivity method in which an array of electrodes is moved along profiles to determine lateral variations in resistivity. AGI resistor A device to provide resistance in an electric circuit, usually to limit the current, dissipate energy, or provide heat. Kentucky 2615

resoiling The replacement of the original topsoil at an opencast site on completion of operations to allow the growing of crops. See also: surface reinstatement resolution a. A measure of the ability of individual components, and of remote-sensing systems, to distinguish detail or to define closely spaced targets. AGI b. The minimum size of a feature that can be detected. See also: resolving power c. The separation of a vector into its components. AGI d. The sharpness with which the images of two closely adjacent spectrum lines, etc., may be distinguished. AGI e. In gravity or magnetic prospecting, the indication in some measured quantity, such as the vertical component of gravity, of the presence of two or more close but separate disturbing bodies. AGI f. In seismic prospecting, the ability to indicate separately two closely adjacent interfaces. AGI g. The ability of an optical or radiation system to separate closely related forms or entities; also, the degree to which they can be discriminated. ASM, 1 resolution limit In gravity and magnetic prospecting, the separation of two disturbing bodies at which some obvious indication in a measured quantity of the presence of two separate bodies ceases to be visible. AGI resolved-time method A seismic reflection technique that involves the plotting of reflections in time and the representation of horizontal distances along the section in equivalent time units (obtained by dividing the true horizontal distance by the sub-weathering velocity as determined from first-arrival times). Once this transformation of the coordinate system is made, migration is accomplished by swinging arcs of reflection times from successive shot points and drawing lines which are tangent to the respective arcs for the same events from adjacent shot points. For the final mapping of migrated horizons in depth, the times are recorded directly beneath the shot points. These times are converted to depths by using the best available velocity information. Dobrin resolving power In optical viewing, the minimum distance possible between two separately distinguishable objects. Pryor, 3 resonance a. A term denoting a variety of phenomena characterized by the abnormally large response of a system having a natural vibration period to a stimulus of the same, or 2616

nearly the same, frequency. AGI b. A buildup of amplitude in a physical system when the frequency of an applied oscillatory force is close to the natural frequency of the system. AGI resonance screen A high-speed vibrating screen in which the applied force has a frequency equal to the natural frequency of the suspended mass. In its basic form, the vibrating frame of the resonance screen is a mass oscillating between two compression springs, that alternately store and return this energy. Nelson resonant frequency drilling Drilling that utilizes longitudinal vibration corresponding to the resonant frequency of the drill string in order to "fluidize" the sediments being sampled, thereby achieving efficient penetration. Padan resorption border A border of secondary minerals, produced by partial resorption and recrystallization, surrounding an original crystal constituent of a rock. Syn: corrosion border resource A concentration of naturally occurring solid, liquid, or gaseous material in or on the Earth's crust in such form and amount that economic extraction of a commodity from the concentration is currently or potentially feasible. USGS, 2 resource characterization The determination of the shape, size, quality, quantity, and variability of the geologic entity and the limits of variable geologic features, so as to provide the information for synthesis of commonly subtle features into an accurate, predictive description of the resource environment. SME, 1 respirable-size particulate Particulates in a size range that permits them to penetrate deep into the lungs upon inhalation. NSC, 2 respirator a. A device (such as a gas mask) for protecting the respiratory tract (against irritating and poisonous gases, fumes, smoke, dusts) with or without equipment supplying oxygen or air. Webster 3rd b. A device for maintaining artificial respiration. Webster 3rd c. The 2617

mining-type respirator is a fitting that covers the nose and mouth to prevent the wearer inhaling excessive quantities of dust. Tunnel miners and workers at sinter plants and blast furnaces are issued respirators for use where danger is known to exist. See also: filter-type respirator; mask. Nelson d. A device worn over the mouth or nose for protecting the respiratory tract from noxious gases or dust. respirator protection factor a. A measure of the degree of protection provided by a respirator to the wearer. FR 166 b. The ratio of the ambient concentration of an airborne substance to the concentration of the substance inside the respirator at the breathing zone of the wearer, a measure of the degree of protection provided by a respirator to the wearer. ANSI respiratory cycle One complete breath--an inspiration followed by an expiration, including any pause that may occur between the movements. Hunt resplendent Referring to a degree of luster that reflects with brilliancy and gives well defined images; e.g., hematite and cassiterite. rest magma See: residual liquid restoration a. Restoring the disturbed land to the conditions which existed at the site before any disturbance occurred. SME, 1 b. The process of gaining or recovering land, bringing it into a condition for cultivation or other use. SME, 1 c. Response to any disturbances to the Earth and its environment caused by mining activity. SME, 1 d. Returning the disturbed site "to a form and productivity in conformity with a prior use plan." SME, 1 e. The Surface Mining Control and Reclamation Act of 1977 (SMCRA) states that, among other provisions, reclamation must "restore the land affected to a condition capable of supporting the uses which it was capable of supporting prior to any mining, or higher or better uses." SME, 1 restore circulation The action taken to fill or seal the cracks or openings through which drill fluid is escaping from the borehole into the rocks forming the walls of the borehole and by which the drill fluid is made to return to and overflow the collar of the borehole. Long 2618

restrained cable plug and socket a. A flameproof restrained plug and socket incorporates an interlock to ensure that the power connections are dead when they are separated or until they make contact; the design is such that the enclosure is flameproof at all times when there is contact between the pins and tubes. BS, 13 b. A plug and socket designed to be held together by an operating bolt, or screwed union ring, or other equivalent device, the use of which enables the plug to be readily inserted or withdrawn. BS, 13 restrained plug and socket These are used when the cable is removed from a machine or apparatus frequently. The most common type is the 100-amp British Standard plug and socket, and it is employed to connect the trailing cable to a coal cutter or face conveyor. The gland of the plug is arranged to grip the sheath of the cable and to make connection with the screen and earth core. Power and pilot conductors are connected to the appropriate contact tubes, which make connection with corresponding pins in the socket portion. Mason restricted earth fault protection As used in mining, a system of earth fault protection in which the fault current is limited, without requiring the use of sensitive earth fault protection. BS, 13 restricted resources That part of any resource category that is restricted from extraction by laws or regulations, but otherwise meets all the requirements of reserves. USGS, 2 rests The arrangement at the top and bottom of a shaft, or intermediate levels, for supporting the shaft cage while changing the tubs or cars. See also: chair; catch; wing. resue a. To mine or strip sufficient barren rock to expose a narrow but rich vein, which is then extracted in a clean condition. Nelson b. To open up a stope, not in the vein but in the wall rock. See also: resuing c. In lode mining, separate removal of undercut barren rock immediately below a lode or vein too narrow for human entry. Following this, the lode is mined and separately removed. Used when the lode is less than 30 in (76 cm) wide. Pryor, 3 resuing

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a. A method of stoping wherein the wall rock on one side of the vein is removed before the ore is broken. Employed on narrow veins, less than 30 in (76 cm), and yields cleaner ore than when wall and ore are broken together. b. A method of stoping in which the ore is broken down first and then the waste or vice versa; usually the one which breaks easier is blasted first. The broken waste is left in the stope as filling, and the ore is broken down on flooring laid on the fill to prevent admixture of ore and waste. Resuing is applicable where the ore is not frozen to the walls and works best if there is considerable difference between the hardness of the ore and of the wall rocks. resurgence See: emergence retaining mesh In sieving or screening, that mesh at which division is made between oversize (arrested on screen) and undersize (passing through meshes). Pryor, 3 retaining ring a. In drilling, a shoulder inside a reaming shell that prevents entry of the core lifter into the core barrel. Long b. A term sometimes incorrectly applied to a core lifter. Long retaining screen The screen that has retained the particles. Pit and Quarry retaining structure A temporary or permanent structure used for holding dredged material on a limited basis, not to be confused with a confined disposal facility. retardation In crystal optics, the amount by which the slow wave falls behind the fast wave during passage through an anisotropic crystal plate. Retardation depends on plate thickness and the difference in refractive indices of its two principal directions. AGI retarding conveyor a. A chain-type conveyor used on steeply inclined faces, where the problem is not so much to move the coal but rather to restrain its movement downhill. It consists of link chains carrying discs 6 to 8 in (15 to 20 cm) in diameter at every yard (0.9 m). The endless chain runs in an open semicircular trough, and the coal is lowered to the discharge end. The chain returns uphill, in an enclosed tube, to the driving unit at the top 2620

end. Its capacity is about 100 tons per hour. Nelson b. Any type of conveyor used to retard the rate of movement of bulk materials, packages, or objects, where the slope is such that the conveyed material tends to propel the conveying medium. See also: declining conveyor retentivity The capacity of a material to retain a portion of the magnetic field set up in it after the magnetizing force has been removed. ASM, 1 retgersite A tetragonal mineral, NiSO4 .6H2 O ; dimorphous with nickelhexahydrite; blue green; associated with morenosite, the septehydrate. Retger's salt Thallium silver nitrate that melts to a yellow liquid at 75 degrees C having a density of 4.6 g/cm3 ; can be diluted and used as a heavy liquid for mineral separation. reticular See: reticulate reticulate a. Said of a vein or lode with netlike texture; e.g., stockwork. CF: stockwork b. Said of a rock texture in which crystals are partially altered to a secondary mineral, forming a network that encloses remnants of the original mineral. CF: mesh texture Syn: reticular reticulated A mineral structure of fibers or columns that cross to resemble a net; e.g., rutile. See also: reticulate reticulated veins Veins that cross each other, forming a network. See also: stockwork reticulate texture See: mesh texture reticule 2621

A set of intersecting very fine lines, wires, etc., in the optical focus of an optical instrument. It is also referred to as graticule. See also: collimation line reticulite An extremely attenuate pyroclastic rock consisting of glass threads which join a series of points forming a polyhedral space lattice. It is formed from pumice by the collapse of the walls of adjacent vesicles and the retraction of the liquid into threads which form the perimeters of the former polygonal faces. The threads are usually of triangular cross section, indicating chilling, before rounding could take place. Such rock has generally been known by Dana's name, thread-lace scoria. See also: thread-lace scoria retiform Netted; reticulate; said of the boundaries of some vein quartz (rare). Hess retigen Bitumen contained in meteorites. The name indicates that this substance on distillation gives rise to resin, in contrast to kerogen which on distillation gives rise to oil. Tomkeieff retinalite A massive, honey-yellow or greenish variety of serpentine with a waxy or resinous luster. retinasphalt A light brown resinous substance found in brown coal in Devonshire, England. Tomkeieff retinite A variety of fossil resin found as rodlets secreted in canals or ducts of coal-forming plants. retinosite A microscopical constituent of torbanite consisting of translucent orange-red discs. CF: gelosite; humosite; matrosite. Tomkeieff retonation wave

2622

A wave passing back through burned or burning explosion gases toward the origin, at the rate of a sound wave through gases of like temperature, from a point in the explosion wave, usually of high pressure, to an area of lower pressure. Rice, 2 retort a. A vessel used for the distillation of volatile materials, as in the separation of some metals and the destructive distillation of coal. ASM, 1 b. A long semicylinder, now usually of fireclay or silica, for the manufacture of coal gas. Webster 3rd c. See: amalgam retort retorting a. Removing the mercury from an amalgam by volatizing it in an iron retort, conducting it away, and condensing it. Fay b. In the sulfur industry, synonymous with sublimation. Fay retort pressman A person who operates a hydraulic press in which fireclay retorts, used in smelting zinc ores, are made. DOT retract The mechanism by which a dipper shovel bucket is pulled back out of the digging. Nichols, 1 retractable wedge A type of deflecting wedge that can be retrieved after the deflected drill hole has been completed. Syn: retrievable wedge retracting See: crowding retreat To work rooms or pillars to finish coal or ore extraction in an area that has been penetrated to its limits by advance work; workings are generally in the opposite direction of advance work and allow the area to be abandoned as finished. BCI retreating longwall

2623

a. First driving haulage road and airways to the boundary of a tract of coal and then mining it in a single face without pillars back toward the shaft. Fay b. See: longwall retreating retreating system a. A method of working a mine that is designed to allow a stope to cave soon after it is worked out, thus relieving the weight on the supports in adjacent stopes. Lewis b. A method of extracting coal or ore by driving a narrow heading to the boundary, then opening out a face and working the deposit backwards towards the shaft, drift, or main entry. See also: longwall retreating Nelson c. A stoping system in which supporting pillars of ore are left while deposit is worked outward from shafts toward the boundary, the pillars being removed (robbed) as the work retreats toward the shaft; the unsupported workings are abandoned and left to cave in. Pryor, 3 d. A system of robbing pillars in which the line of pillars being robbed retreats or moves from the boundary toward the shaft or mouth of the mine. See also: longwall retreating retrievable inner barrel The inner barrel assembly of a wire-line core barrel, designed for removing core from a borehole without pulling the rods. Long retrievable wedge See: retractable wedge retrieving ring A catch ring on a retractable wedge that engages a lifting device on the deflection barrel or bit, enabling the drill runner to remove a deflecting wedge from a borehole after deflection has been effected. Long retrograde metamorphism The mineralogical adjustment of relatively high-grade metamorphic rocks to temperatures lower than those of their initial metamorphism, characteristically inducing hydration and hydrous minerals. Syn: retrogressive metamorphism; diaphthoresis. CF: prograde metamorphism retrogressive metamorphism See: retrograde metamorphism return 2624

a. Any airway in which vapid air flows from the workings to the upcast shaft or fan. See also: intake b. Any airway which carries the ventilating air from the face outby and out of the mine. BS, 8 c. Any surface turned back from the face of a principal surface. ACSG, 1 d. The rate of profit in a process of production per unit of cost. Webster 3rd return air a. Air traveling in a return. BS, 8 b. Air that has circulated the workings and is flowing towards the main mine fan; vitiated or foul air. Nelson c. Air returning to a heater or conditioner from the heated or conditioned space. Strock, 2 return aircourse Portion of ventilation system of mine through which contaminated air is withdrawn and evacuated to surface. Pryor, 3 return circulation That portion of a circulated drill fluid flowing from the face of a bit toward the collar of a borehole. CF: return water returning charge Charge made per unit of ore or concentrate treated by smelter in custom smelting. In addition to a basic charge that allows for process costs and agreed percentage loss in recovery, extra charges may be specified, or remitted as premiums, in adjustment of variations from the normal makeup of the parcel treated. Pryor, 3 returning fluid The water, mud, or other circulated medium reaching the borehole collar after having been circulated past the drill bit. Long return-line corrosion tester A tester developed by the U.S. Bureau of Mines for detecting and controlling corrosion in steam-condensate-return lines of large heating plants. This tester determines types and rates of corrosion and can distinguish among various possible causes. It is assembled from ordinary black iron pipe nipples and couplings, the linings are easily machined, and the corroded linings can be analyzed quickly in any laboratory. return man In anthracite coal mining, one who resets timbers, shovels up falls of slate, rock, or dirt, and keeps in general repair the airways by which mine air returns to the surface. DOT 2625

returns a. The drill fluid and entrained sludge that overflows the collar of a borehole. Long b. In seismic reflection prospecting, the signals reflected back to the surface from layer boundaries in the subsurface. c. Also used in geophysical prospecting to register passage of waves caused by detonation of dynamite. Hess return water Drill fluid that reaches the surface and overflows the borehole collar after it has been circulated downward through the rods and past the drill bit. Long retzian An orthorhombic mineral, (Mn,Mg)2 (Ce,La,Nd)(AsO4 )(OH)4 ; speciated on the basis of predominance of cerium, lanthanum, or neodymium; in dolomite cavities in Sweden. reussin An impure Glauber's salt (mirabilite), found native. Standard, 2 reussinite A resinlike, reddish-brown oxygenated hydrocarbon, soluble in boiling alcohol and in ether. Found in certain coal deposits. revdanskite An impure, hydrous nickel silicate from Revda (Revdinsk), Ural Mountains, Russia. Also spelled revdinite, revdinskite, rewdinskit, rewdanskite; rewdjanskit, and refdanskite. English; Hey, 1 revegetation The process of restoring or replacing the botanical species upon an area disturbed by mineral operations. Revegetation is a customary requirement for reclamation of a mineral operation. SME, 1 reverberate a. To deflect flame or heat, as in a reverberatory furnace. Fay b. To reduce by reverberated heat; to fuse. Fay reverberation 2626

a. The persistence of sound in an enclosed space as a result of multiple reflections after the sound source has stopped. Hunt b. The sound that persists in an enclosed space, as a result of repeated reflection or scattering, after the source of the sound has stopped. Hunt reverberatory furnace A furnace, with a shallow hearth, usually non-regenerative, having a roof that deflects the flame and radiates heat toward the hearth or the surface of the charge. Firing may be with coal, pulverized coal, oil, or gas. Two of the most important types are the openhearth steel furnaces and the large reverberatories employed in copper smelting. ASM, 1; CTD; Newton, 1 reversal A local change of approx. 180 degrees in the direction of the regional dip. reversal of ventilation In the case of a centrifugal fan, the reversal arrangement may consist of an emergency drift connecting the fan with the downcast shaft. The drift is normally sealed off by airtight doors. In the case of an axial-flow fan, it is only necessary to reverse the rotation of the fan. This arrangement entails a reduction in volume and pressure in the reversed airflow. Nelson reverse bearing In surveying, a sight along the reverse direction of a line; the reciprocal of a given bearing. See also: backsight reverse bend To bend a line over a drum or a sheave, and then in the opposite direction over another sheave. Nichols, 1 reverse book fashion The manner in which drill core is laid in a core box, starting at the upper-right-hand corner of the box and laying core from right to left in each groove. CF: snake fashion reverse circulation The circulation of bit-coolant and cuttings-removal liquids, drilling fluid, mud, air, or gas down the borehole outside the drill rods and upward inside the drill rods. Also called countercurrent; counterflush. See also: circulating fluid 2627

reverse-circulation core barrel A core barrel designed so that core tends to float within the barrel when the fluid is circulated down the outside of the rods and returned to the surface inside the rods. Long reverse classification In jigging, stratification of particles by size with largest uppermost; in streaming, rolling effect of transporting current that arranges particles with smallest nearest feed end. Pryor, 3 reverse-current braking A method used in the braking of alternating-current winders. This method absorbs power equal to the energy destroyed and dissipates it in the liquid controller as heat. Two phases of the stator supply are interchanged by bringing back the driver's lever to the off position and then to that for the opposite direction of drum rotation. The amount of braking depends upon the position of the lever, since the lower the resistance in the controller, and therefore in the rotor circuit, the greater the rotor current and the braking torque produced. When the direction of rotation of the stator magnetic field is reversed, the voltage between the stator and the rotor is doubled and the insulation of both must be adequate to prevent breakdown. Sinclair, 5 reversed See: overturned reversed bratticing A method of narrow heading ventilation in coal mines by means of a brattice partition. The air is led to the face along the wide section of the heading and the contaminated air returns from the face along the narrow section. In this way, workers in the heading are placed in relatively clean air. Nelson reversed fault See: reverse fault reversed flush boring See: counterboring reversed loader

2628

A front-end loader mounted on a wheel tractor having the driving wheels in front and steering at the rear. Nichols, 1 reverse fault A fault on which the hanging wall appears to have moved upward relative to the footwall. The dip of the fault is usually greater than 45 degrees . There is dip separation but there may or may not be dip slip. CF: normal fault AGI reverse feed To move bit and drill stem backwards away from the borehole bottom while the drill stem is rotated. Long reverse-feed gear System of gears in drill swivel head that can be engaged to move the bit and drill stem backwards away from the bottom of the borehole while the drill stem is rotated in a clockwise direction. Syn: backup gear; reverse gear. Long reverse gear See: reverse-feed gear reverse initiation See: inverse initiation reverse laid rope A wire rope with alternate strands right and left lay. Hunt reverse reaming See: ream back reversible auxiliary ventilation In this system, a single duct is provided and is normally operated by a blowing fan. After blasting, airflow is reversed and the fumes and dust are exhausted. Ventilation is again reversed to blowing, when the work at the face is resumed. The usual arrangement is to use two fans, one for forcing, one for exhausting, at the mouth of the heading. This arrangement is particularly suited to underground use as it allows clean air to be drawn from, and contaminated air to be discharged to, separate points in the main airways. See also: auxiliary ventilation; two-fan auxiliary ventilation. 2629

reversible endless-rope system A haulage system in which a single rope is used passing around a surge wheel. A single track may be used or, if more than one train is hauled, a single track with passbys, or a three-rail system with passbys, that eliminates facing points, may be used. The system may be operated at higher speeds than normal endless systems since the trains are attached and detached from a rope at rest; it has been used for the haulage of workers at speeds up to 12 mph. Extra rope must be spliced onto the rope, and the return wheel moved forward, when the system is extended. Sinclair, 5 reversible pick See: double-ended pick reversible transducer See: bilateral transducer reversing clutch A forward-and-reversing transmission that is shifted by a pair of friction clutches. Nichols, 1 reversing doors The system of doors or shutters on or near a surface radial-flow fan for reversing the direction of the air passing through a mine. BS, 8 reversing machine A molding machine having a flask or flasks that may be turned over for ramming the sand. Standard, 2 reversing mill A type of rolling mill in which the stock being mechanically worked by rolling passes backwards and forwards between the same pair of rolls, which are reversed between each pass. See also: continuous mill; three-high mill. CTD reversing shaft A shaft whose direction of rotation can be reversed by the use of clutches or brakes. Nichols, 1 reversing thermometer 2630

A mercury-in-glass thermometer used to measure temperatures of the sea at depth. The temperature is recorded when the thermometer is inverted; and the recording is maintained until it is once again upright. A protected thermometer and an unprotected thermometer are usually used as a pair, attached to a Nansen bottle. AGI revetment a. A facing, sheathing, or retaining wall of masonry or other materials for protecting a mass or bank of earth, etc., as in fortifications and riverbanks. Standard, 2 b. A wall sloped back sharply from its base. Nichols, 1 revolution An obsolete term for a time of profound orogeny and other crustal movements, on a continentwide or even worldwide scale, the assumption being that such revolutions produced abrupt changes in geography, climate, and environment. See: orogeny revolving screen A screen consisting of a cylindrical (sometimes conical) screening surface mounted on a revolving frame for sizing coarse material; it is still common in gravel-washing, coalwashing, and stone-treating plants, but is not widely used in ore dressing. See also: trommel; trommel screen. Newton, 1 revolving shovel A digging machine that has the machinery deck and attachment on a vertical pivot, so that it can swing independently of its base. Nichols, 1 revolving washing screens The rotary washing screen is cylindrical in shape and made of three sections--a scrubber, a sand jacket, and a gravel-screening section--mounted on a steel frame. Pit and Quarry rewash To re-treat a product in the same or in another washer. BS, 5 rewash box A washbox to which the product (or a portion thereof) of a previous washing operation is fed for additional treatment. BS, 5 rewdanskite 2631

See: revdanskite reworked Said of components derived from an older sedimentary formation and incorporated in a younger one. Reynolds number A numerical quantity used as an index to characterize the type of flow in a hydraulic structure in which resistance to motion depends on the viscosity of the liquid in conjunction with the resisting force of inertia. It is the ratio of inertia forces to viscous forces, and is equal to the product of a characteristic velocity of the system (e.g., the mean, surface, or maximum velocity) and a characteristic linear dimension, such as diameter or depth, divided by the kinematic viscosity of the liquid; all expressed in consistent units in order that the combinations will be dimensionless. The number is chiefly applicable to closed systems of flow, such as pipes or conduits where there is free water surface, or to bodies fully immersed in the fluid so the free surface need not be considered. AGI Rf value In paper-strip chromatography, ratio of distance moved by component in solution under test to that of transporting solvent. Pryor, 3 rhabdite See: schreibersite rhabdomancy A form of dowsing using a rod or twig. CF: dowsing rhabdophane a. A hexagonal mineral, (Ce,La,Nd)PO4 .H2 O ; speciated on the basis of predominance of cerium, lanthanum, or neodymium; Also spelled rhabdophanite. b. The mineral group brockite, grayite, ningyoite, rhabdophane-(Ce), rhabdophane-(La), rhabdophane-(Nd), and tristramite. rheid a. A substance below its melting point that deforms by viscous flow during the time of applied stress at an order of magnitude at least three times that of the elastic deformation under similar conditions. b. A body of rock showing flow structure. 2632

rheid folding Folding accompanied by slippage along shear planes at an angle to the bedding or older foliation. rheidity The capacity of material to flow within the earth. AGI Rhenania furnace A combination of the Hasenclever and O'Hara furnaces, with four hearths, and with a combination flue under the lowest hearth and one over the upper hearth. It has mechanical rabbles. Fay Rhenish furnace A zinc distillation furnace that is a modified type of the Silesian furnace. Fay rhenium A rare, silvery-white metal. Symbol, Re. Occurs in very small quantities in platinum ores and in columbite, gadolinite, and molybdenite. Used for filaments for mass spectrographs and ion gages; for thermocouples and photoflash lamps. Handbook of Chemistry and Physics, 3 Rheolaveur washer A washer wherein raw coal and water is fed into the head of an inclined trough equipped with openings in the bottom for the discharge of rejects. There are three types of Rheolaveurs used in coal washing: (1) the sealed discharge type for coarse sizes, from which the reject falls against an upward current of water and is removed by an automatic gate that controls the feed to a drowned elevator; (2) a system of two, three, or four superimposed troughs for washing fine coal below about 1/2 in (1/3 cm). The troughs are equipped with several bottom discharge devices. The separation of the heavy shale from coal and middlings takes place progressively until finally the pure shale is discharged from the lowest trough, and (3) a system for washing slurry consisting usually of two troughs one above the other and equipped with a number of Rheo boxes of the open discharge type but designed to minimize the loss of coal with the fine shale. Nelson rheology Study of the flowage of materials, particularly plastic flow of solids and flow of nonNewtonian liquids. AGI 2633

rheomorphism The process by which a rock becomes mobile and deforms viscously as a result of at least partial fusion, commonly accomplished, if not promoted, by addition of new material by diffusion. rheostat a. An instrument for testing blasting machines by inserting definite resistance equal to a known number of electric blasting caps of a standard-length wire, using one electric blasting cap as an indicator. b. An instrument by which a variable or an adjustable resistance may be introduced into a circuit to regulate the strength of a current, as in the field coils of a motor or a generator. Standard, 2 rheostat rope A small rope consisting of 8 strands of 7 wires each. Hunt rhinestone a. Quartz and other material cut to imitate diamond. b. Glass backed with a thin leaf of metallic foil to simulate a diamond. c. Originally a syn. of quartz crystal. d. Cut colored glass. rhodesite An orthorhombic mineral, (Ca,Na2 ,K2 )8 Si16 O40 .11H2 O ; fibrous; resembles zeolites; at Bultfontein Mine, Kimberley, South Africa. See also: mountainite rhodite See: rhodium gold rhodium a. An element of the platinum group, Symbol: Rh. b. An isometric mineral, RhPt . rhodium gold Native gold alloyed with rhodium. rhodochrome Chromian clinochlore, formerly called kaemmererite. 2634

rhodochrosite A trigonal mineral, MnCO3 ; calcite group, with Mn replaced by Fe toward siderite, Ca toward calcite, Mg, Zn, Co, and Cd; rhombohedral cleavage; in hydrothermal veins, residual manganese deposits, and pegmatites; a minor source of manganese. Syn: manganese spar See also: dialogite; raspberry spar. rhodolite A pale pink, rose, or purple to violet variety of pyrope garnet having good transparency; may be of gem quality. rhodonite A triclinic mineral, (Mn,Fe,Mg,Ca)SiO3 ; a pyroxenoid; in metasomatic manganese ore deposits; an ornamental stone, esp. in Russia. Syn: manganese silicate; manganese spar. See also: red manganese rhodotilite See: inesite rholites A word employed by Wadsworth to designate smelting materials or fluxes. Fay rhomb See: rhombus; rhombohedron. rhombarsenite See: claudetite rhombenglimmer See: biotite rhombic See: rhombus; orthorhombic. rhombic dodecahedron

2635

The isometric form hh0 having twelve faces in the shape of a rhombus; e.g., garnet. CF: pyritohedron rhombic mica See: phlogopite rhombic quartz An old name for feldspar. Fay rhombic system a. In crystallography, same as the orthorhombic system. Syn: orthorhombic system b. A former name for the orthorhombic system. rhomboclase An orthorhombic mineral, HFe(SO4 )2 .4H2 O ; forms colorless to gray rhombic plates; in Slovakia. rhombohedral division In assigning point groups to six crystal systems, those members of the hexagonal system that may be assigned rhombohedral crystallographic axes a r belong to the rhombohedral division of the hexagonal system. They have a unique triad, but not all point groups with a unique triad may be assigned rhombohedral axes; hence, not all trigonal point groups are rhombohedral. CF: trigonal; trigonal system. rhombohedral iron ore See: siderite rhombohedral system a. Same as the hexagonal system, except that the forms are referred to three axes parallel to the faces of the fundamental rhombohedron instead of to the usual four axes. Fay b. The trigonal division of the hexagonal system, the forms being referred to the same three axes as above. Neither usage has been generally accepted. Fay rhombohedron A parallelepiped with each face a rhombus. Dolomite crystallizes as rhombohedra, and members of the calcite group cleave as rhombohedra. Adj. rhombohedral. 2636

rhomboid A parallelogram that does not have any right angles, and one pair of opposite sides differ in length from the other pair of opposite sides. Jones, 2 rhomb spar See: dolomite rhombus A parallelogram that does not have any right angles, but the sides are all equal in length. Jones, 2 rhoenite A triclinic mineral, Ca2 (Fe,Mg,Ti)6 (Si,Al)6 O20 ; aenigmatite group; in silicaundersaturated mafic to intermediate rocks commonly as an alteration product of amphiboles; in Germany and the Czech Republic. rhums Scot. Bituminous shale. rhyacolite See: sanidine rhyodacite The extrusive equivalent of granodiorite. The principal minerals, sodic plagioclase, sanidine, quartz, and biotite or hornblende, commonly occur as phenocrysts in a finely crystalline groundmass of alkali feldspar and quartz. Accessory minerals are apatite and magnetite, and occasionally augite. AGI rhyolite A group of extrusive igneous rocks, typically porphyritic and commonly exhibiting flow texture, with phenocrysts of quartz and alkali feldspar in a glassy to cryptocrystalline groundmass; also, any rock in that group; the extrusive equivalent of granite. Rhyolite grades into rhyodacite with decreasing alkali feldspar content and into trachyte with a decrease in quartz. The term was coined in 1860 by Baron von Richthofen (grandfather of the World War I aviator). Etymol: Greek rhyo-, from rhyax, stream of lava. See also: liparite 2637

rhyolite glass Obsidian. rhyolite-porphyry A rhyolite in which some grains or crystals are visibly larger than others. Sinkankas rhythmic crystallization A phenomenon, observed in igneous rocks, in which different minerals crystallize in concentric layers, giving rise to orbicular structure. AGI rhythmic driving In this type driving, the drilling, loading, and blasting are carried out in one shift and the mucking and transportation in the following one. This enables every worker to specialize in his or her tasks and machines, which in a highly mechanized job is a necessary condition for making the best use of expensive equipment. It also reduces or eliminates the loss of time for ventilation; in rhythmic driving it is carried out between two shifts. Langefors rhythmic sedimentation A regular interbanding of two or more types of sediment or sedimentary rocks due to a regular change in the conditions of sedimentation, such as alternation of wet and dry periods. See also: varved clay rhythmite The couplet of distinct types of sedimentary rock, or the graded sequence of sediments, that form a unit bed or lamina in rhythmically bedded deposits. It implies no limit as to thickness of bed, lamina, or complexity, but the term should exclude groups of beds such as cyclothems and carries no time or seasonal connotation. CF: cyclothem; varve. AGI rib a. The side of a pillar or the wall of an entry. BCI b. The solid coal on the side of a gallery or longwall face; a pillar or barrier of coal left for support. c. The solid ore of a vein; an elongated pillar left to support the hanging wall in working out a vein. d. A stringer of ore in a lode. e. The termination of a coal face. Where solid coal is left, the term fast rib, end, or side, is used; and where the coal face ends at the gob, the term used is loose rib, end, or side. TIME f. See: buttock g. A hard zone, bed, or horizon within a formation; a silicified zone in a sedimentary stratum. Long h. A ridge projecting above 2638

grade in the floor of a blasted area. Nichols, 1 i. A ridge, paralleling the long axis of a drill string member, that acts as a wear-resistant surface. Long ribbed roll A crusher in which the material passes between a moving set of rolls with ribs on their surfaces parallel to the axis of the rolls. See also: roll ribbing Enlarging a heading or drift. ribbon a. One of a set of parallel bands or streaks in a mineral or rock, e.g., ribbon jasper; when the lines of contrast are on a larger scale, the term banding is used. See also: stripe b. Said of a vein having alternating streaks of ore with gangue or country rock, or simply of varicolored ore minerals. CF: banded; book structure. AGI c. A color band in slate that represents original bedding and crosses the superimposed slaty cleavage. Ribbon is generally undesirable and decreases the value of the slate. Syn: pancake ribbon brake A friction brake having a metal strap that encircles a wheel or drum and may be drawn tightly against it. A band brake. Standard, 2; Fay ribbon diagram Geologic cross section drawn in perspective and joining control points along a sinuous line. AGI rib boss See: pillar boss rib dust Dust found on the side walls of a mine. The dust from the roof is generally included with this sample. Rice, 2 rib hole Final holes fired in blasting around sides of shaft or tunnel. Also called trimmer. Pryor, 3 rib line 2639

A continuous line along which pillars are mined. See also: break line Lewis rib lining In rod or ball mill, replaceable ribs that project longitudinally from shell liners so as to act as lifters for crop load as mill rotates. Pryor, 3 rib mesh Expanded metal stiffened at intervals with bent steel plates. Hammond rib pillar A pillar whose length is large compared with its width. ribs The lines or ridges of cut gems that distinguish the several parts of the work, both of brilliants and roses. Hess rib-side The side of a heading or roadway driven in the solid coal. See also: narrow stall rib-side gate A gate road in longwall mining with a rib of solid coal along one side. Nelson rib-side pack A pack formed by working 5 to 10 yd (4.6 to 9.1 m) of coal along a rib-side of a road and packing the waste. See also: roadside pack; skipping. Nelson rice coal a. Anthracite coal of a small size; No. 2 Buckwheat coal. See also: anthracite coal sizes b. A steam size of anthracite. Jones, 1 Richards' pulsator classifier A classifier operating in such a manner that the pulp grains fall through a sorting column against an upward pulsating current of water. It has no screen. Liddell Richards' pulsator jig 2640

An outcome of the pulsator classifier, in which a pulsating column of water is used in the jig. See also: pulsator jig Richards' shallow-pocket hindered-settling classifier A series of pockets through which successively weaker streams of water are directed upward. The material that can settle does so, and is drawn off through spigots. Liddell richetite A triclinic mineral, PbU4 O13 .4H2 O ; strongly radioactive; black; occurs embedded among fine needles of uranophane. richmondite a. A discredited mineral term since a number of specimens have proved to be mixtures containing, in order of abundance, argentian tetrahedrite, galena, sphalerite, chalcopyrite, pyrite, and perhaps stromeyerite. Am. Mineral., 1 b. A mixture of sulfide minerals containing silver, lead, zinc, and copper. rickardite An orthorhombic mineral, Cu7 Te5 ; pseudotetragonal; deep purple; at Vulcan and Bonanza, CO; Warren, AZ; and Salvador, Brazil. ricket An airway along the side of an adit or shaft. Also called ricketing. rid See: redd ridding N. of Eng. Separating ironstone from coal shale. See also: redd Fay riddle a. A barrel-shaped, revolving perforated drum in which blank coins are washed and dried after passing through a bath of sulfuric acid. Standard, 2 b. A coarse sieve. The large pieces of ore and rock picked out by hand are called knockings. The riddlings remain on the riddle; the fell goes through. Webster 3rd; Fay c. A sieve used to separate foundry sand or other granular materials into various particle-size grades or free such a material of undesirable foreign matter. ASM, 1 2641

ride over Arkansas. A squeeze that extends into the workings beyond the pillar. It is said to ride over a pillar. Fay rider a. A thin coal seam above a workable seam, or a seam that has no name. Nelson b. The rock lying between two lodes or beds; a mass of country rock enclosed in a lode; a horse. c. An ore deposit overlying the principal vein. Standard, 2 d. A steel or iron crossbeam which slides between the guides in sinking a shaft. It is carried up and down by, but is not attached to, the hoppit, which it guides and steadies. ridge a. A long, narrow elevation of the Earth's surface, generally sharp crested with steep sides, either independently or as part of a larger mountain or hill. b. A long elevation of the deep-sea floor having steeper sides and less regular topography than a rise. AGI ridge fillet A runner or principal channel for molten metal. Standard, 2 ridge terrace A ridge built along a contour line of a slope to pond rainwater above it. Nichols, 1 Ridgeway fiter A horizontal, revolving, continuous vacuum filter. The surface is an annular ring consisting of separate trays with vacuum and compressed air attachments. The filtering surface is on the underside, the trays being dipped into the tank of pulp to form the cake and then lifted out of it. Liddell riding Said of mine timbering when the sets are thrust out of line, or lean. Ridley-Scholes bath Dense-media system used to float coal away from shale, the latter falling to the bottom of a wedge-shaped pool of separating fluid and being withdrawn by a rising belt. Pryor, 3 rid-up runners 2642

To clean up after a cast, as when the scrap, slag, and iron is removed from runners, troughs, and skimmers, and they are freshly clayed, loamed, or sanded. Fay riebeckite A monoclinic mineral, Na2 Ca(MgFe+2 )5 Si8 O22 (OH)2 ; amphibole group with Mg/(Mg+Fe2+ ) = 0 to 0.49 and Fe3+ /(Fe3+ +Al) = 0.7 to 1.0; forms a series with magnesioriebeckite; fibrous; in soda-rich rhyolites, granites, and pegmatites; crocidolite variety is blue asbestos, tiger eye is crocidolite replaced by quartz. CF: glaucophane Riecke's principle The statement in thermodynamics that solution of a mineral tends to occur most readily at points where external pressure is greatest, and that crystallization occurs most readily at points where external pressure is least. It is applied to recrystallization in metamorphic rocks with attendant change in mineral shapes, such that mass is transferred from contact points to pressure shadows resulting in reduced rock porosity. It is named after the German physicist E. Riecke (1845-1915) although it was actually discovered and described by Sorby in 1863. AGI riemannite See: allophane riffle a. A natural shallows extending across a stream bed over which the water flows swiftly and the water surface is broken into waves; a shallow rapids of comparatively little fall. AGI b. The lining of the bottom of a sluice, made of blocks or slats of wood or stones, arranged in such a manner that chinks or slots are left between them, into which heavy mineral grains fall and are held for recovery. c. The raised portions of the deck of a concentrating table, that serve to trap the heaviest particles. Syn: ripple d. A device used to reduce the volume or weight of a sample consisting of a thin metal plate on which is mounted a series of metal strips to guide or deflect a small portion of the sample material into a separate container. CF: sample splitter e. Sample reducing device such as Clark riffler or Jones riffle, which splits a batch sample of ground ore into two equal streams as it falls across an assembly of deflecting chutes. See also: sludge sampler CF: Jones splitter riffle bars Slats of wood nailed across the bottom of a cradle or other gold-washing machine for the purpose of detaining the gold. riffle box 2643

A device designed to reduce a sample of coal or ore to half its original size. The box contains about 12 chutes discharging alternately to opposite sides. The width varies according to the largest particle size. The volume reduction is rapid for dry material of suitable fineness. Nelson riffler See: sample splitter rifle a. As used by drillers, a borehole that is following or has followed a spiral or corkscrew course; also said of a drill core that has spiral grooves appearing on its outside surface. Long b. A drill hole, in rock, that has become three-cornered while drilling. c. Applied to the three-cornered section of a hole drilled by hand. Though the bit is supposed to be turned one-eighth after each blow, to insure a circular hole, the majority of hand-drilled holes are three-cornered. Stauffer rifle bar A cylinder with curved splines. Nichols, 1 rifle nut A splined nut that slides back and forth on a rifle bar. Nichols, 1 rifling a. Working coal which was left behind over the waste. Nelson b. The spiral grooving in the walls of a drill hole and/or on the surface of a drill core. Long c. A borehole following a spiraled course. Long rift a. A regional-scale strike-slip fault, e.g., the San Andreas rift in California, with offset measured in hundreds of kilometers. AGI b. A trough or valley formed by faulting. c. In quarrying, a direction of parting in a massive rock, such as granite, at approx. right angles to the grain. CF: grain; hard way. AGI d. A narrow cleft, fissure, or other opening in rock (such as in limestone), made by cracking or splitting. AGI e. A planar property whereby granitic rocks split relatively easily in a direction other than the sheeting (parallel to the surface of the Earth.) AGI f. A term used in slate quarrying to describe a second direction of splitting less pronounced than slaty cleavage and usually at right angles to it. g. In sedimentary rocks, the horizontal plane of stratification, or the bed of the rock. Stauffer h. An obscure foliation, either vertical (or nearly so) or horizontal, 2644

along which a rock splits more readily than in any other direction. Syn: fault trace i. A crack, such as in the mid-ocean ridges. MacCracken rifter-trimmer One who separates blocks of mica into sheets and trims sheets preparatory to processing. Also called full trimmer. DOT rifting The process of splitting hand-cobbed mica into sheets of usable thicknesses. Skow rift structure A long, narrow structural trough that is bounded by normal faults; a graben of regional extent. CF: rift valley rift valley a. A valley that has developed along a rift structure. Syn: fault trough b. The deep central cleft in the crest of the mid-oceanic ridge. Syn: midocean rift rift zone a. A system of parallel crustal fractures; a rift structure. AGI b. In Hawaii, a zone of volcanic features associated with underlying dike complexes. Syn: volcanic rift zone rig a. A drill machine complete with auxiliary and accessory equipment needed to drill boreholes. Long b. To assemble and set up a tripod, derrick, and/or drill machine and put it in order for use. Syn: rig up c. A general term denoting any machine. More specif., the front or attachment of a revolving shovel. See also: drilling rig Nichols, 1 rigged Drill machine and equipment in place at a drill site and ready to start drilling. Long rigger One who, with special equipment and tackle, moves and transports heavy machinery, etc. Crispin rigging 2645

a. Process of setting up a drill and its auxiliary equipment preparatory to drilling. Syn: setting up b. The cables or ropes anchoring a drill derrick, mast, or tripod. See also: guy c. Sometimes used as a term for derrick, mast, or tripod complete with anchor, stay ropes, and cables. Long d. The equipment or gear such as hoists, tackle, winches, chains, or rope used by riggers in their work. e. The engineering design, layout, and fabrication of pattern equipment for producing castings; including a study of the casting solidification program, feeding and gating, risering, skimmers, and fitting flasks. ASM, 1 rigging bar A long, extension-type jack bar or drill column for use underground, on which a drilling machine can be mounted. Long right-angled block In quarrying, a block of stone bounded by three pairs of parallel faces, all adjacent faces meeting at right angles. right bank The bank of a stream that is on the right when one looks downstream. right-hand cutting tool A cutter, all of whose flutes twist away in a clockwise direction when viewed from either end. ASM, 1 right-hand feed screw A diamond-drill feed screw that rotates in a clockwise direction. Long right-hand lay Rope or strand construction in which wires or strand are laid in a helix having a righthand pitch. See also: lay right lang lay Wire or fiber rope or cable in which the individual wires or fibers forming a strand and the strands themselves are both twisted to the right. Also called right long lay. Long right-lateral fault A fault on which the displacement is such that the side opposite the observer appears displaced to the right. CF: left-lateral fault Syn: dextral fault 2646

right lay Wire or fiber rope or cable in which the strands formed from a group of individual wires or fibers are twisted to the right. Long right line A straight line; the shortest distance between two points. Crispin right long lay See: right lang lay right-of-way A grant by Act of Congress, to convey water over or across the public domain, for mining purposes. right regular lay Wire or fiber rope or cable in which the wires or fibers in the strand are twisted to the left and the strands to the right. Syn: regular-lay right lay right running a. N. of Eng. Applied to a vein carrying ore in beds often unproductive. b. N. of Eng. Rake veins extending approx. east and west. rigid arch A continuous arch which is fully fixed throughout. Hammond rigid coupling A rod-to-feed-screw sub or rod-to-drive-rod sub by means of which the drill rods are coupled directly to the feed screw or drive rod of the diamond-drill swivel head, and the chuck is discarded or eliminated. Also called screw-to-rod adapter. Long rigid double tube See: rigid-type double-tube core barrel rigid ducts See: ventilation ducts 2647

rigid foam Formed by mixing isocyanate and a polyether polyol containing a halogenated hydrocarbon agent. Mixing releases heat, causing the foam to expand as much as 30 times the original volume of the liquid. The foam, which becomes cellular and rigid within minutes, is heat resistant and essentially impervious to air and water, and has substantial binding strength. Its characteristics suggest possible uses in mining for insulation, stoppings to control ventilation, and seals to control water and to consolidate broken ground. Encyclopaedia Britannica rigid frame A framed structure having columns and beams rigidly connected; there are no hinged joints in this type of structure. Hammond rigid hammer crusher A machine in which size reduction is effected by elements rigidly fixed to a rotating horizontal shaft mounted in a surrounding casing. BS, 5 rigidity The property of a material to resist applied stress that would tend to distort it. A fluid has zero rigidity. AGI rigidity modulus See: modulus of rigidity rigid pavement A road, taxitrack, or hardstanding constructed of concrete slabs. Hammond rigid solution Solubility of solution of elements in a natural glass as compared with a solid solution that implies crystallinity. rigid-type double-tube core barrel A double-tube core barrel in which both the outer and inner tubes are rigidly connected to a single headpiece. Syn: rigid double tube Long rigid urethane foam 2648

See: rigid foam rig-up See: setting up rig up See: rig rig-up time The time required to set up and make a drill rig ready for use at the site where a borehole is to be drilled. Also called setup time; rigging time; mobilizing a rig. Long rill To mine ore in such as way that it runs down a slope to a chute or loading level. Ore is said to be rilled to a chute when it is rolled down a slope left in mining. Hess rill stope Overhand stope so shaped that miners can stand on the ore they have severed, and work horizontally along the side walls of unbroken ore that confine the excavation. The stope is carried as an inverted stepped pyramid, its apex ending in a winze that leads to the tramming level, down to which ore gravitates or is moved. Pryor, 3 rim a. The border, edge, or face of a cliff, as at the Grand Canyon of Arizona. AGI b. The outermost portion of a zoned crystal, e.g., a reaction rim. AGI rim flying A reconnaissance method in which a plane follows an outcrop along steep canyon walls, keeping where possible within 50 ft (15 m) of the face of the cliff. This type of prospecting has been successful in discovering new deposits in the Colorado Plateau region. Dobrin rimmed steel A low-carbon steel containing sufficient iron oxide to give a continuous evolution of carbon monoxide while the ingot is solidifying, resulting in a case or rim of metal virtually free of voids. Sheet and strip products made from the ingot have very good surface quality. ASM, 1 2649

rimrock a. The outcrop of a horizontal layer of resistant rock, such as sandstone, at the edge of a plateau, butte, or mesa; the cliff or ledge so formed. b. The bedrock rising to form the boundary of a placer deposit. rimrocking Prospecting for carnotite on the Colorado Plateau, where the favorable beds, more or less flat-lying, crop out in cliffs or rims. rim texture A texture in ores where the metasome forms a narrow rim around grains of the host mineral. rim walking Prospecting a canyon rim with a Geiger counter. Ballard rincon a. A term used in the Southwestern United States for a recess or hollow in a cliff or a reentrant in the borders of a mesa or plateau. Also called a cove. b. A term used in the Southwestern United States for a small, secluded valley. c. A bend in a stream.--Etymol: Spanish rincon, inside corner, nook. ring a. A complete circle of tubbing plates around a circular shaft. Syn: tunnel lining b. Troughs placed in shafts to catch the falling water, and so arranged as to convey it to a certain point. c. See also: wedging crib d. S. Staff. A circular piece of wrought iron, about 8 in (20 cm) deep, placed on the top of a skip of coal to increase its capacity. ring arch One composed of a series of straight, unbonded rows, one brick wide. ring coal a. An old name for bituminous coal. Tomkeieff b. Bituminous coal as opposed to stone coal or anthracite. Arkell ring complex 2650

An association of ring dikes and cone sheets. AGI ring crusher a. A type of hammermill with a high-speed horizontal shaft upon which a series of steel rings are swung. ACSG, 2 b. Impact mill, beater mill, or hammermill, in which the beaters are loosely swinging rings. Pryor, 3 c. See also: hammermill ring-cut Holes in a ring around one central hole used to carry a cavity forward, usually six. Pryor, 3 ring dike A subcircular to circular dike with steep dip. Ring dikes may be many kilometers long, and hundreds or thousands of meters thick. Their radius is generally from 1 to 20 km. Although some ring dikes may form a nearly complete circle, more commonly they encompass 1/4 to 3/4 of a circle or ellipse. They are commonly associated with alkalic igneous complexes and carbonatites, so are probably related to deep shock effects or to cauldron subsidence. Ring dikes are commonly associated with cone sheets to form a ring complex. Syn: ring-fracture intrusion ringed out A diamond bit in the face of which has been gouged a circular groove deeper than, and at least as wide as, the diameter of one row of the inset diamonds. Long ringer A crowbar. Fay ring fault A steep ring-shaped fault, complete or incomplete. It is associated with cauldron subsidence. ring-fracture intrusion See: ring dike ring holes The group of boreholes radially drilled from a common-center setup. See also: horadiam; radial drilling. Long 2651

ring-induction method An inductive method in which the primary coil and the measuring coil are concentric. Schieferdecker ringing The audible or ultrasonic tone produced in a mechanical part by shock, and having the natural frequency or frequencies of the part. The quality, amplitude, or decay rate of the tone may sometimes be used to indicate quality or soundness. ASM, 1 ring main Closed loop of piping, including provision for entry of material, circulation boost and controlled withdrawal points; used for circulating solids such as pulverized fuel, or fluids such as lime slurry, continuously without settlement or chokeup. Pryor, 3 ring ore Fragments of gangue covered with deposits of other minerals. See also: cockade ore ring pit A circular pit in which a large wheel is revolved for tempering clay. Fay ring-roll crusher A type of crusher in which high-speed rolls act on the inside circumference of a vertical cylinder to powder raw material like clay. Enam. Dict. ring-roll grizzly A sturdily built grizzly for handling large pieces of ore. This type transports its material across a series of grooved rollers moved mechanically, or alternatively by the sliding ore. Undersize falls through the grooves. Pryor, 3 ring-roll press A press consisting of rolls of unequal diameter, revolving one within the other and in the same direction. BS, 5 Ringrose methane recorder A recorder that gives a continuous record in the range of 0% to 3%. Roberts, 1 2652

Ringrose pocket methanometer A small instrument that is capable of estimating methane in the range of 0% to 2% . Roberts, 1 ring-shaped occurrences In some areas altered rock has been found as a halo over an orebody and thus serves as a geologic target for guiding prospecting operations. The ratio between the size of the ring and the orebody must not be too large for practical purposes. Such target rings are not always obvious and will only be recognized after much painstaking work and study. Also called bulls-eye alteration patterns. Lewis ring stone a. A voussoir showing on the face of the wall. Webster 3rd b. Eng. Large oolitic grains in very hard crystalline matrix, above the slates at Collyweston, U.K. CF: sun bed ring stress The zone of stress, higher than that pre-existing in the rock, which surrounds all development excavations is called the ring stress. Spalding ring-stress bursts In stoping, the ring stresses around a level, rise, or winze are so increased by the influence of an approaching stope face that at some point on the periphery the rock fails. The stress ring is broken, and the rock of sides, back, and bottom released thereby expands suddenly and violently into the excavation, causing a rock burst. This rock burst is identical in type with those occurring in development. It is usually extremely local in effect, though a heavy earth tremor is caused. Spalding ring tension Tension that develops in the wall of a circular tank containing liquid or solid material. Hammond ring-type reaming shell In drilling, a reaming shell, the inset reaming diamonds of which are set into a cast- or powder-metal band encircling the outside surface of the shell. Long ring-type wedge

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A drill-hole deflecting wedge having a short metal sleeve attached to the uppermost end. The outside diameter of the sleeve is the same as that of the lower, full-circle part of the wedge. Long ring wall The inner firebrick wall of a blast furnace. Standard, 2 rinkite A monoclinic mineral, (Na,Ca,Ce)3 Ti(Si2 O7 )2 OF3 ; weakly radioactive; forms prismatic crystals in veins containing silicates of cerium metals, yttrium, and niobium; near Barkevik, Norway, in sodalite syenite in the Julianehaab district, Greenland, and in large crystals on the Kola Peninsula, Russia. Also spelled rinkolite. Syn: johnstrupite Rinman scale A Swedish standard scale for the estimation of slag inclusions in iron and steel. This scale consists of a series of micrographs, designed to show different typical fields of view, and arranged in groups according to the form and distribution of the inclusions and numbered according to their quantity. Osborne rinneite A trigonal mineral, K3 NaFeCl6 ; colorless to varicolored; becomes brown on exposure to air and has an astringent taste. rinsing In the ion-exchange (IX) cycle, applied to pregnant leach liquors, the displacement wash used after the absorption cycle, which moves pregnant liquor still in the column onto the next absorption column in the series. Term also applied to water rinse used after elution cycle, and before acid rinse. Pryor, 3 rinsing water a. Water used to remove fine particles from larger sizes, usually located over vibrating screens. BS, 5 b. Syn: spray water Rio Tinto process Heap leaching of cupriferous sulfides after their slow oxidation to sulfates on prolonged atmospheric weathering. Pryor, 3 rip 2654

a. To bring down rock in a roadway to increase headroom. See also: dint Fraenkel b. See: brush riparian a. Pertaining to or situated on the bank of a body of water, esp. of a watercourse such as a river; e.g., riparian land situated along or abutting upon a stream bank, or a riparian owner who lives or has property on a riverbank. AGI b. Pertaining to shrubs and trees with root systems that seek deep ground water, as mesquite and greasewood. AGI riparian rights The rights of a person owning land containing or bordering on a watercourse or other body of water in or to its banks, bed, or waters. Under common law, a person owning land bordering a nonnavigable stream owns the bed of the stream and may make reasonable use of its waters. rip current A strong surface current of short duration flowing seaward from the shore. It usually appears as a visible band of agitated water and is the return movement of water piled up on the shore by incoming waves and wind. Syn: rip tide rippability A measure of the ease or difficulty with which a rock or earth material can be broken by tractor-drawn rippers or rigid steel tines into pieces that can be economically moved by other equipment, usually scrapers. ripper a. Coal miner who breaks down the roof of a gate road to increase headroom or breaks down the roof at the ripping lip, or where the roof has sagged on a roadway due to subsidence. The miner is often paid on yardage of ripping performed. Also known as brusher; stoneman; repairer. See also: trenchman; stoneman. Pryor, 3 b. A tool for removing slates, or edging them. Standard, 2 c. An accessory that is either mounted or towed at the rear of a tractor and generally used in place of blasting as a means of loosening compacted soils and soft rocks for scraper loading. The ripper has long, angled teeth that are forced into the ground surface, ripping the earth loose to a depth of 2 ft (0.6 m) or more. Carson, 1 d. See: rooter ripping a. A machine for cutting stone into slabs by passing it on a bed under a gang of saws. Standard, 2 b. The act of breaking, with a tractor-drawn ripper or long-angled steel 2655

tooth, compacted soils or rock into pieces small enough to be economically excavated or moved by other equipment such as a scraper or bulldozer. c. The breaking down of the roof in mine roadways to increase the headroom for haulage, traffic, and ventilation. See also: brushing; second ripping. Nelson ripping bed A machine for cutting stone into slabs by passing it on a bed under a gang of saws. Standard, 2 ripping blasting Where coal seams are worked by the longwall method it is necessary to maintain roadways leading to the face. These roadways should be of sufficient height to permit the easy passage of workers and materials, and this invariably means that some of the stone above the coal must be removed. This operation is known as ripping, and, unless the roof strata are very soft, blasting will be required. The main considerations in ripping blasting are to keep the sides of the roadway square, and to obtain good fragmentation of the stone so that it can be removed easily. McAdam, 2 ripping face support A timber, or timber and steel structure, to provide support at the ripping lip. There are various types: one consists of bent corrugated steel bars behind which wooden planks are wedged; another consists of adjustable stretchers that are fitted across the roadway. See also: roadhead Nelson ripping lip a. The edge of the rippings at the face of a roadway. When enlarging a roadway, the ripping lip is the end of the enlarged section and where work is proceeding. See also: forepoling girder b. The edge of the nether roof at a gate end at the point up to which the ripping has been taken. TIME ripping scaffold A staging or platform erected over the moving conveyor at a ripping lip of a gate road, on which the miners can stand and work. This implies that the coalface and conveyor loading point are some distance ahead. Nelson rip plates A means of repairing damaged belting. It consists of two short plates, with teeth on one side to grip the belting, which are fastened on both sides of the belting across the rip or 2656

worn place. Short bolts and nuts serve to compress and hold the plates tightly against the belting. Jones, 1 ripple A groove or bar across sluices for washing gold. See also: riffle ripple board An inclined trough having grooves or strips across its bottom to catch fine gold. See also: riffle ripple index The ratio of wavelength to amplitude of a ripple mark. It usually ranges from 6 to 22 for ripples produced by water currents or waves and from 20 to 50 for ripples produced by wind. Syn: ripple-mark index ripple mark a. An undulatory surface or surface sculpture consisting of alternating subparallel smallscale ridges and hollows formed at the interface between a fluid and incoherent sedimentary material (esp. loose sand). It is produced on land by wind action and subaqueously by currents or by the agitation of water in wave action, and generally trends at right angles or obliquely to the direction of flow of the moving fluid. It is no longer regarded as evidence solely of shallow water. AGI b. One of the small and fairly regular ridges, of various shapes and cross sections, produced on a ripple-marked surface; esp. a ripple preserved in consolidated rock and useful in determining the environment of deposition. The term was formerly restricted to symmetrical ripple mark, but now includes asymmetrical ripple mark. The singular form may be used to denote general ripple structure (as well as a specific ripple), and the plural form to describe a particular example. ripple-mark index See: ripple index ripple voltage The alternating component of a substantially unidirectional voltage. Coal Age, 1 riprap a. A layer of large, durable fragments of broken rock, specially selected and graded, thrown together irregularly (as offshore or on a soft bottom) or fitted together (as on the 2657

upstream face of a dam). Its purpose is to prevent erosion by waves or currents and thereby preserve the shape of a surface, slope, or underlying structure. It is used for irrigation channels, river-improvement works, spillways at dams, and sea walls for shore protection. AGI b. The stone used for riprap. AGI rip tide See: rip current rise a. A vertical or inclined shaft from a lower to an upper level in a mine. See also: upraise; raise. Eng. Min. J., 1 b. To dig upward, as from one level to the next one above; opposite of sink. Standard, 2 c. Upward inclination of a coal stratum. Standard, 2 d. An ascending gallery at the end of a level. See also: hade Gordon rise and fall A system of reduction of levels by working out the rise or fall of staff readings from each level point to the one following it. See also: collimation rise face A face advancing toward the rise of a coal seam. Briggs rise heading A heading driven to the rise in a long-way workings. See also: heading riser a. A shaft excavated from below upward. See also: raise; rise. Fay b. See: column pipe; rising main. rising a. An excavation carried from below upward; a rise or riser. Standard, 2 b. Eng. The horizontal division of the stratum, from which the blocks of stone are lifted; e.g., in the Portland quarries. Arkell rising column See: rising main rising current 2658

The direction in which a drill circulation fluid is flowing after it has passed the bit and continues toward the collar of a borehole. Long rising-head test A soil permeability test in which the level of water in a borehole is reduced and then the rate at which the water recovers is observed. Mining rising main a. The length of steel piping that conveys the water from a pump to the surface or to a higher pump in the shaft. The term rising main is obsolete; delivery column preferred. Syn: delivery column Nelson b. See: column pipe rising shaft Excavating a shaft upwards from mine workings. See also: rise; staple shaft. Nelson rittingerite See: xanthoconite Rittinger's law The energy required for reduction in particle size of a solid is directly proportional to the increase in surface area. CF: Kick's law CCD, 2 Rittinger table A side-bump table with plane surface, actuated by a cam, spring, and bumping post. Liddell rivelaine A pick with one or two points, formed of flat iron, used to undercut coal by scraping instead of striking. Fay river bar A ridge or mound of boulders, gravel, sand, and mud found along or in a stream channel at places where decrease in velocity causes deposition of sediment. river-bar placer

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a. Gravel flats and terraces laid down by rivers when flowing at higher levels than at present. The deposits are sometimes gold or tin-bearing. See also: bench placer b. A term used in Alaska for placers on gravel flats in or adjacent to the beds of large streams. river claim A claim that includes the bed of a river. river drift The gravel deposits accumulated by a river in its torrential stages. river flat See: alluvial flat river mining Mining or excavating beds of existing rivers after deflecting their course, or by dredging without changing the flow of water. river pebble Applied in Florida to a certain class of phosphatic pebbles, or concretions, found in rivers as distinguished from land pebble phosphate. river plain See: alluvial plain river quartz Rounded, waterworn masses of quartz found in stream gravels. river right See: creek right river run gravel Natural gravel as found in deposits that have been subjected to the action of running water. See also: alluvial deposit river sand 2660

Sand generally composed of rounded particles, and may or may not contain clay or other impurities. It is obtained from the banks and beds of rivers. Zern rives in Eng. To crack open or produce fissures. rivet A round bar of mild steel having a conical, cup- or pan-shaped head, which is driven while red hot into a hole through two plates of steel that have to be joined together. Aluminum, copper, and other materials are also used for rivets. See also: pneumatic riveter riveter A worker who forms the head of a rivet, generally with a pneumatic rivet hammer. Hammond rivet forge A portable forge, used by boilermakers and ironworkers, for heating rivets near the work for which they are required. Crispin rivet heater A laborer responsible for heating rivets in a portable forge and throwing them with tongs to the rivet catcher. Hammond rivet snap A punch having a recess in its head shaped to the form of the rivet. See also: pneumatic riveter rivet test A test on the steel used for rivets, in which a bar is bent through 180 degrees ; if any cracks are formed, the steel is rejected. Hammond rivet tester A trained worker who can detect sound or loose rivets by testing them with a hammer. Hammond riving seams 2661

Open fissures between beds of rock in a quarry. R.K. process A method for converting pig iron into a product with a low carbon content, which is suitable as a substitute for steel scrap for remelting in steel furnaces. Osborne road a. A roadway in a mine, e.g., gate road, traveling road, dummy road. Nelson b. Any mine passage or tunnel. Mason c. Rail track. Mason roadbed a. The material fundamental part of a road; primarily, the foundation of gravel, road metal, etc., constituting the bed, but by extension, esp. in railway use, the superstructure also. Standard, 2 b. The foundation carrying the sleepers, rails, chairs, points, and crossings, etc., of a railway track. CTD road cleaner See: track cleaner road dust Dust found on the floor of a mine entry. Rice, 2 roadhead The face of a roadway, usually in longwall conveyor mining. The records indicate that the roadhead is the most dangerous place in a coal mine based on accidents from falls of ground. See also: ripping face support Nelson road-making plant Various types of specialized plant used solely for road construction, including such machines as planers, scarifiers, rollers, pavers, finishers, gritters, and mixers. Hammond roadman a. A person employed on the laying and maintenance of rail tracks underground. Also known as a trackman. Nelson b. A person whose duty it is to keep the roads of a mine in order. Fay c. In bituminous coal mining, a general term for miners working along haulageways or airways (roads). Usually designated according to job, as repairman; wasteman. DOT 2662

road metal Crushed stone for surfacing macadamized roads, and for the base course of asphalt and concrete roadways; also used without asphaltic binder as the traffic-bearing surface, generally on secondary roads. AGI road-mix method A method of preparing aggregates for bituminous surfaces in which the aggregates and bitumen are combined on the surface of the road, using the penetration or mixed-in-place method. Pit and Quarry road roller Power-driven roller of any weight from one-half to 12 tons. Hammond roadside pack A pack built alongside a roadway. See also: rib-side pack Nelson roadster Low-priced model of a scraper or a truck. Nichols, 1 roadway An underground drivage. It may be a heading, gate, stall, crosscut, level, or tunnel and driven in coal, ore, rock or in the waste area. It may form part of longwall or bord-andpillar workings or an exploration heading. A roadway is not steeply inclined. See also: roadway support Nelson roadway cable An electric cable designed for use in mine roadways. It may be either rubber insulated, sheathed, and armored or paper insulated. Nelson roadway consolidation To bind the floor dust together with water and calcium chloride flakes, or other chemical, to form a firm plastic carpet. See also: dust consolidation roadway support A timber, steel, concrete, or other erection in a roadway to (1) ensure safety by preventing falls of ground, and (2) maintain the maximum possible roadway size by 2663

resisting the tendency of the roadway to contract and distort. See also: steel arch; roadway. Nelson roast To heat to a point somewhat short of fusing, with access of air, as to expel volatile matter or effect oxidation. Fay roaster A reverberatory furnace or a muffle used in roasting ore. Standard, 2 roaster slag Slag resulting from the calcination of white metal in the process of copper smelting. Standard, 2 roasting a. Heating an ore to effect some chemical change that will facilitate smelting. ASM, 1 b. The operation of heating sulfide ores in air to convert to oxide or sulfate. CTD c. Calcination, usually with oxidation. Good, dead, or sweet roasting is complete roasting; i.e., it is carried on until sulfurous and arsenious fumes cease to be given off. Kernel roasting is a process of treating poor sulfide copper ores, by roasting in lumps, whereby copper and nickel are concentrated in the interior of the lumps. Fay d. The heating of solids, frequently to promote a reaction with a gaseous constituent in the furnace atmosphere. See also: magnetizing roast ARI roasting and reaction process The treatment of metal ore in a reverberatory, by first partly roasting at a low temperature and then partly fusing the charge at a higher temperature, which causes a reaction between the lead oxide formed by roasting and the remaining sulfide, producing sulfurous acid and metallic lead. Syn: air-reduction process roasting and reduction process The treatment of lead ores by roasting to form lead oxide, and subsequent reducing fusion in a shaft furnace. Fay roasting cylinder A furnace with a rotating cylinder for roasting, amalgamating, or smelting ore. See also: Bruckner furnace 2664

roasting furnace A furnace in which finely ground ores and concentrates are roasted to eliminate sulfur or other elements or compounds; heat is provided by the burning sulfur. The essential feature is free access of air to the charge, by having a shallow bed that is continually rabbled. Many types have been devised; multiple hearth is the most widely used. CTD roast sintering See: blast roasting roast stall A form of roasting furnace, built in compartments or stalls open in front, with flues running up the wall at the back for the purpose of creating a draft. rob To extract mine pillars previously left for support, often preparatory to closing a mine. Syn: second mining. robber a. In anthracite and bituminous coal mining, one who breaks down and rips out with a pick, pillars of coal left to support the roof in rooms when the usual mining was being done. Also called pillar robber. DOT b. An extra cathode or cathode extension that reduces the current density on what would otherwise be a high current-density area on the work. ASM, 1 robbing a. Removing timber from a mined-out stope to use it again elsewhere. Stoces b. Extraction of the pillars of ore left to support workings during original stoping. Pryor, 3 c. Scot. Reducing the size of pillars; taking as much as possible off pillars, leaving only what is deemed sufficient to support the roof. robbing an entry See: drawing an entry robbing pillars The mining of coal pillars left to support the roof during development mining, often resulting in cave-ins. See also: working the broken 2665

Robiette process A heat treatment process carried out in a substantially closed furnace, in which a fluid fuel is burnt to partial combustion with a gas containing 70% or more of oxygen to produce a nonoxidizing atmosphere. The treatment is effected continuously in the furnace through which the heating gas and metal are passed in opposed directions. The fuel and gas are partially burnt at the exit end of the furnace, and passed to the cooler entry end of the furnace, and burnt to substantially complete combustion so as to preheat metal entering the furnace. Osborne Robins-Messiter system A stacking conveyor system in which material arrives on a conveyor belt and is fed to one or two wing conveyors. This part of the system moves so as to form a long ridge; reclaimed by raking gear that works across the ridge, moving slowly forward and shifting material loosened and blended by the rake action by means of a spiral that pushes it to a reclaiming conveyor at the side of the ridge. Used to stockpile ore, concentrates, and coal. Pryor, 3 Robinson and Rodger system A method of obtaining sound steel by fluid compression of the ingot in the mold. The molds are divided in the center, a removable packing piece being placed between the halves of the mold. The packing piece is removed when the metal has set, and the mold is placed horizontally in the press, pressure being applied to the ingot at both ends. Osborne robinsonite A triclinic mineral, Pb4 Sb6 O13 . robot loader A pneumatic loader for inserting cartridges into drill holes. Robson and Crowder process An early oil flotation process. The oil was added to several times its weight of ore and mixed in a slowly revolving drum or tube. The process at one time had quite a large application. The process used but little water (25% to 30%) and no acid. Fay Roburite Smokeless and flameless safety explosive consisting of ammonium nitrate and dinitrobenzene or dinitrochloro benzene; used in mines. Bennett 2666

roca a. Sp. Rock or stone, whether in the ordinary or geological sense. b. Sp. Rock standing out from the general surface. c. Sp. A vein or bed of hard rock and stone. roche Fr. Rock, boulder. rock a. An aggregate of one or more minerals, e.g., granite, shale, marble; or a body of undifferentiated mineral matter, e.g., obsidian, or of solid organic material, e.g., coal. AGI b. Any prominent peak, cliff, or promontory, usually bare, when considered as a mass, e.g., the Rock of Gibraltar. AGI c. A rocky mass lying at or near the surface of a body of water, or along a jagged coastline, esp. where dangerous to shipping. AGI d. A slang term for a gem or diamond. AGI e. Strictly, any naturally formed aggregate or mass of mineral matter, whether or not coherent, constituting an essential and appreciable part of the Earth's crust. Ordinarily, any consolidated or coherent and relatively hard, naturally formed mass of mineral matter; stone. In instances, a single mineral forms a rock, as calcite, serpentine, kaolin, and a few others but the vast majority of rocks consist of two or more minerals. f. A local term used in New York and Pennsylvania for the more massive beds of bluestone that are not jointed and are, therefore, well-suited for structural purposes. g. In the geological sense, any natural deposit or portion of the Earth's crust whatever be its hardness or softness, but used by miners to denote sandstone. TIME h. In geology, the material that forms the essential part of the Earth's solid crust, and includes loose incoherent masses, such as a bed of sand, gravel, clay, or volcanic ash, as well as the very firm, hard and solid masses of granite, sandstone, limestone, etc. Most rocks are aggregates of one or more minerals, but some are composed entirely of glassy matter, or of mixtures of glass and minerals. Hunt i. In the Lake Superior region, crude copper ore as it comes from the mines. The concentrate obtained is called mineral, and contains about 65% metallic copper. rock asphalt See: asphalt rock rock association a. A group of igneous rocks within a petrographic province that are related chemically and petrographically, generally in a systematic manner such that chemical data for the rocks plot as smooth curves on variation diagrams. See also: tribe AGI b. The association of mineral deposits with certain rock types. If mineral-producing localities are considered individually, valuable generalizations often can be made, and 2667

lithotectonic-plate tectonic classifications of ore deposits and exploration strategies derived from them. rock base See: bedrock rock bit a. Any one of many different types of roller or drill bits used on rotary-type drills for drilling large-size holes in soft-to-medium-hard rocks; also sometimes applied to dragtype bits. See also: drag bit; roller bit. Long b. In mining, a detachable-type chisel or cruciform bit used on percussive drills to drill small-diameter holes in rock. Long c. See: drill bit rock body A dump body with oak planking set inside a double steel floor. Nichols, 1 rock bolt A bar, usually constructed of steel, that is inserted into pre-drilled holes in rock and secured for the purpose of ground control. Rock bolts are classified according to the means by which they are secured or anchored in rock. In current usage there are mainly four types: expansion, wedge, grouted, and explosive. See also: roof bolt rock bolting a. See: roof bolting b. The process of rock bolting consists of (1) anchoring the bolt in a hole; (2) applying tension to the bolt to place the rock under compression parallel to the bolt; and (3) placing the bolts in such a pattern that they will properly support the rock structure. Rock may be supported by bolts in five ways: (1) suspension; (2) beam building; (3) reinforcement of arched opening requiring support; (4) reinforcement of an opening otherwise self-supporting; and (5) reinforcement of walls against shear and compressive action. See also: roof bolting rockbridgeite An orthorhombic mineral, (Fe,Mn)Fe4 (PO4 )3 (OH)5 ; forms a series with frondelite; dark green; named for Rockbridge County, VA. rock bump

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The sudden release of the weight of the rocks over a coal seam or of enormous lateral stresses due to structural or tectonic folds and thrusts and sometimes both. A rock bump may take the form of a pressure bump or a shock bump. Nelson rock burst A sudden and often violent breaking of a mass of rock from the walls of a tunnel, mine, or deep quarry, caused by failure of highly stressed rock and the rapid or instantaneous release of accumulated strain energy. It may result in closure of a mine opening, or projection of broken rock into it, accompanied by ground tremors, rockfalls, and air concussions. See also: burst; pressure bump. AGI rock butter A soft yellowish mixture of alum with aluminum and iron oxides; a decomposition product of aluminous rocks. See: stone butter Standard, 2 rock car runner See: car runner rock channeler A machine used in quarrying for cutting an artificial seam in a mass of stone. It is made in several forms, the principal types being the bar channeler (in which the cutters are mounted on a carriage that works along a heavy bar or bars) and the track channeler. Standard, 2 rock chute See: chute; rock hole. Also called slate chute. rock-chute mining See: bord-and-pillar method rock cleavage The property or tendency of a rock to split along closely spaced planar structures, produced by deformation or metamorphism. See also: schistosity rock cone bit See: roller bit 2669

rock contractor In anthracite coal mining, one who contracts to mine rock, as distinguished from coal, at a certain price per ton or footage of advance. DOT rock cork A light-colored variety of asbestos. Syn: mountain cork; rock leather. Standard, 2; Fay rock cover Thickness of consolidated rock above the roof of an opening (equivalent to cover, minus depth of weathering or of other soil). CF: cover rock crusher A machine for reducing rock or ore to smaller sizes. Three principal types are the jaw crusher, the gyratory, and the hammer crusher. rock crystal a. Transparent quartz. ASTM b. Highly polished brown glassware, hand-cut or engraved. ASTM rock cut A way, esp. for a railroad, cut through a rock or rocky formation. Mathews rock cuttings See: cuttings; sludge. rock cycle A sequence of events involving the formation, alteration, destruction, and reformation of rocks as a result of such processes as magmatism, erosion, transportation, deposition, lithification, and metamorphism. A possible sequence involves the crystallization of magma to form igneous rocks that are then broken down to sediment as a result of weathering, the sediments later being lithified to form sedimentary rocks, which in turn are altered to metamorphic rocks. AGI rock dredge a. A dredge that excavates rock for the purpose of deepening harbors and waterways; also, a device for sampling underwater outcrops and boulders. b. A general term for a 2670

seabed sampling device consisting of a heavy bucket frame that is pulled across the seabed on a cable controlled by a winch operator on deck. rock drift A horizontal mine passage cut in rock, esp. along a vein on a principal level of a mine. See: crosscut; stope. rock drill a. A machine for boring relatively short holes in rock for blasting purposes. It may be a sinker, jackhammer, drifter, or stoper. See also: percussive drill; rotary drill. Syn: Waugh drill Nelson b. A roller bit. Long c. A conical bit for drilling hard rock. AGI rock-drill bit See: rock bit rock driller a. In bituminous coal mining, one who works in rock or slate as distinguished from coal. Also called rock shooter; slate driller. DOT b. See: rock splitter rock drivage A hard heading or stone drift. Nelson rock dust a. The general name for any kind of inert dust used in rendering coal dust inert or in filling rock-dust barriers. Equivalent to the British stone dust. Rice, 2 b. The dust produced in mines by blasting, drilling, shoveling, and handling rock. Rock dust in suspension varies in particle size and composition. The most dangerous dusts are silica, sericite, and asbestos; but all fine dusts are health hazards when inhaled. The smaller sizes, 10 microns and less, are more dangerous than the larger sizes. Wet drills, sprays, water infusion, and ample ventilation are employed to reduce the dust menace. See also: dust consolidation; dust-free conditions; stone dust; stone-dust barrier. Nelson rock-dust barrier a. A device that releases a large quantity of inert dust in the air in the path of an explosion, extinguishing the flame. Rice, 2 b. A series of troughs or shelves laden with rock dust and so arranged that the air waves from an explosion will trip them and fill the air with rock dust and thus quench the flame of exploding coal dust. 2671

rock duster a. A machine that distributes rock dust over the interior surfaces of a coal mine by means of air from a blower or pipeline or by means of a mechanical contrivance, to prevent coal dust explosions. Also called rock-dust machine. b. See: rock-dust man rock dusting a. The dusting of underground areas with powdered limestone to dilute the coal dust in the mine atmosphere and on the mine surfaces, thereby reducing explosion hazards. b. A very widespread control measure used in coal mines to combat explosive dusts. By machine, inert (combustible) dust is sprayed, dry or wet, on the roof, floor, and ribs in all working places and haulageways, to reduce the explosibility of settled coal dust. The Mine Safety and Health Administration requires rock dusting to within 40 ft (12 m) of the face. The incombustible content of settled dust samples after rock dusting must constitute 65% or more by weight, with an increase of 1% for each 0.1% methane present. A dust as nearly inert, physiologically, as possible, should be employed in rock dusting; limestone (calcium carbonate) is most widely used. Hartman, 2 rock-dusting machine A machine consisting essentially of a flexible hose fed by a powerful blower. It is used in forcing rock dust, usually powdered limestone, onto the floor, walls or ribs, and rooms and entries of a mine, thereby making the coal dust nonexplosive. rock-dust man In bituminous coal mining, a laborer who sprinkles rock dust by hand or with a machine throughout mine workings as a precaution against explosions. Syn: rock duster DOT rock-dust testing kit This kit is designed to prevent coal-dust explosions. It helps to determine the explosion hazard prior to rock dusting, the fineness of the rock dust as it comes from the pulverizer, and the percentage of combustible matter present in rock and coal dust mixtures after rock dusting. Best, 1 rock-dust zone A section of a mine entry, the ribs, roof, and floor of which have been coated with rock dust. Rice, 2 rocker

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a. A small digging bucket mounted on two rocker arms in which auriferous alluvial sands are agitated by oscillation, in water, to collect gold. A shortened term for rocker shovel; rocker arm shovel. b. Used for testing placer deposits and for working pockets and small placer deposits. The gold-bearing gravel is placed on the screen; gold and fine sand are washed through the screen, and remaining stones are cleaned out. A chute directs the material to the upper end of the bottom, which may be covered with small transverse riffles or canvas. Waste material passes over a tailpiece at the end of the rocker. Rockers range in length from 6 to 12 ft (2 to 4 m), and in bottom width from 14 to 20 in (35 to 50 cm), with holes in the screens from 1/4 to 1/2 in (0.6 to 1.2 cm) in diameter. The slope of the rock should be adjusted to the nature of the gravel and is commonly 1 in 12, ranging from 1 in 8 to 1 in 20. Two workers with a rocker can handle from 3 to 5 yd3 (2.3 to 3.8 m3 ) of gravel in place in 10 h if the ground is easily rocked. Lewis c. A portable sluicebox used by prospectors and fossickers in treating alluvial mineral deposits. Also called rocking cradle. Pryor, 3 rocker arm a. A lever resting on a curved base so that the position of its fulcrum moves as its angle changes. Nichols, 1 b. A bell crank with the fulcrum at the bottom. Nichols, 1 rocker arm shovel See: rocker shovel rocker bottom See: rocker rocker dump car Among the smaller capacity cars, the most popular and most widely used are the gravity dump types, such as rocker dump and scoop cars, designed so that the weight of the load tips the body when a locking latch is released by hand. The body of this type is balanced to right itself after the load is discharged. Rocker dump cars range in capacity from 1 yd3 (0.76 m3 ) handloaded types, to units of 10 yd3 (7.6 m3 ) for power shovel loading. Pit and Quarry rocker shovel A digging and loading machine consisting of a bucket attached to a pair of semicircular runners that when rolled, lifts and dumps the bucket load into a car or other materials transport unit behind the machine. rocker sieve 2673

A miner's cradle or rocker, a cradlelike device for washing out mud from the contents of a dredge. Mathews rock excavation In situ removal of all firm, unaltered, and unweathered surface geological materials. rock fabric See: fabric rock factor See: resistance to blasting rock failure Fracture or failure of a rock that has been stressed beyond its ultimate strength. AGI rockfall a. The relatively free falling or precipitous movement of a newly detached segment of bedrock (usually massive, homogeneous, or jointed) of any size from a cliff or other very steep slope; it is the fastest form of mass movement and is most frequent in mountain areas and during spring when there is repeated freezing and thawing of water in cracks in the rock. Movement may be straight down, or in a series of leaps and bounds down the slope; it is not guided by an underlying slip surface. AGI b. The mass of rock moving in or moved by a rockfall; a mass of fallen rocks. Also spelled rock fall. AGI rock fault Eng. A replacement of a coal seam over a greater or lesser area by some other rock, usually sandstone. See also: horse; washout. Fay rock-fill dam An earth dam built of any broken rock or similar material that may be available. Hammond rock filling a. Waste rock, used to fill up worked-out stopes to support the roof. Weed, 2 b. See: overhand stoping rock flour 2674

a. Powdered rock material formed by the grinding-up of rocks beneath a glacier, either deposited as part of the till or washed or blown away and deposited elsewhere as stratified drift or loess. Also called glacier meal. Syn: rock meal b. Fault gouge. rock flow a. The movement of solid rock when it is in a plastic state. Leet, 1 b. The term given to a slope failure when there is a general breakdown of the rock mass. When such a rock mass is subjected to shear stresses sufficient to break down the cement or to cause crushing of the angularities and points of the rock blocks, the blocks will move as individuals and the mass will flow down the slope, or will slump into a more stable slope position. Woodruff rock formation See: formation rock-forming mineral A mineral that is common and abundant in the Earth's crust; one making up large masses of rock. From 20 to 30 minerals are usually considered as being the most important. Stokes rock foundation A foundation that is carried down to the solid rock. The rock is cut and dressed level, loose and decayed portions are removed, and holes filled with concrete. The crushing strength of the rock can be ascertained by tests and the bearing pressure should not exceed one-eighth of the value. Nelson rock fracture When rock is broken by crushing or impact, the resulting fragments can be divided into two components: (1) the complement, comprising a wide size distribution in accordance with a probability law, and (2) the residue of large incompletely broken pieces. The relative proportions of complement and residue depend upon the mode of fracture. If the rock is completely crushed, only complement is formed, but if the rock is fractured by the impact of a point or wedge, there may be more residue than complement. Syn: complement rock glacier An ice-cored mass of angular rock waste, usually heading in a cirque or other steepwalled amphitheater and in many cases grading into a true glacier. 2675

rock glass Obsidian or other volcanic glass. rock gypsum A massive, coarsely crystalline to finely granular, sedimentary rock of the mineral gypsum with bedding commonly disturbed by expansion during hydration of parent anhydrite. Syn: gyprock rock hardness The resistance of the rock to the intrusion of a foreign body. Stoces rockhead a. The upper surface of bedrock. b. The boundary between superficial deposits (or drift) and the underlying solid rock. BS, 11 c. See: bedrock rock hole A short staple shaft driven from a lower to a higher coal seam and used for the gravity transfer of coal to the haulage road in the lower seam. See also: roofing hole rock hound An amateur mineralogist or collector. rocking a. The process of separating ores by washing on an incline trough. See also: rocker b. Pushing a resistant object repeatedly, and backing or rolling back between pushes to allow it to reach or cross its original position. Nichols, 1 rocking beam See: walking beam rocking cradle Short sluice, hand-oscillated; used in gold prospecting and fossicking. See also: rocker rocking lever A beam to give the reciprocal motion in hand boring. Nelson 2676

rock kicker Usually found at sand and gravel processing facilities. A mechanical device consisting of a roller (with rows of metal protrusions along its length) placed at a 45 degrees angle just ahead of a feed hopper (or conveyor transfer point). It is usually run by a small electric motor and as roots, large stones, and clay meet the roller, they are dumped off the belt to a small pit that is periodically cleaned out. rock kindred See: rock association rock leather See: mountain leather rock loader a. Any device or machine used specif. for loading slate or rock inside a mine. However, it is most frequently used with scraper loaders equipped for handling rock. Syn: rockloader operator b. See: box loader rock-loader operator See: rock loader rockman In bituminous coal mining, a foreman who is in charge of the drilling of holes in rock or slate and the charging and tamping of explosives in the holes drilled by miners prior to blasting. See also: slateman DOT rockman helper See: slate-shooter helper rock meal See: rock flour rock mechanics a. Mathematical analysis of the forces acting along joints, faults, and bedding planes of natural rock in situ, esp. in the evaluation of wall strengths, and hence slopes and slope ratios, in open-pit mines. b. The theoretical and applied science of the physical behavior 2677

of rocks, representing a branch of mechanics concerned with the response of rock to the force fields of its physical environment (NAS-NRC, 1966). AGI rock melt A liquid solution of rock-forming mineral ions at sufficiently high temperatures to be considered molten. rock milk Soft pulverulent forms of calcite found in caves, or as an efflorescence. See: agaric mineral rock miner In anthracite and bituminous coal mining, a miner who works in rock as distinguished from coal. DOT rock navvy A cranelike loading machine used at opencast pits and quarries. See also: power shovel rock pedestal See: pedestal rock phosphate See: phosphate rock rock pillar See: hoodoo rock pressure a. The pressure exerted by surrounding solids on the support system of underground openings, including that caused by the weight of the overlying material, residual unrelieved stresses, and pressures associated with swelling clays. AGI b. The compressive stress within the solid body of underground geologic material. AGI c. See: ground pressure; geostatic pressure. d. In petroleum geology, the pressure under which fluids, such as water, oil, and gas, are confined in rocks. No particular cause or origin of the pressure is implied. Geophysicists and isostasis, however, have used, and are using, the term rock pressure in the primitive and more correct sense of the pressure exerted on underlying rock by superincumbent strata. To avoid confusion, it is desirable to 2678

substitute for the term rock pressure, as now used in oil, gas, and underground water technology, the more appropriate term reservoir pressure. Stokes rock pressure burst A sudden and violent failure of rock masses under stresses exceeding the elastic strength of the rock. The classification and nomenclature of these occurrences are not clear and are based largely on effects and not on the basic causation factor. See also: pressure bump; rock bump; rock burst. Nelson rock quartz Ordinary crystalline quartz. Also called rock crystal. rock rake A heavy duty rake blade. Nichols, 1 rock roll Inverted ridges of rock, usually sandstone, extending from the overlying strata into a coal seam, caused by localized streams active during the formation of the coal. See also: classical washout rock ruby A fine red variety of pyrope garnet. See also: pyrope rock salt Coarsely crystalline halite, NaCl, resulting from evaporation of saline water; in massive, fibrous, or granular aggregates; occurs as a nearly pure sedimentary rock, as extensive beds, or in domes or plugs. See also: common salt; salt. rock sediment The combined cuttings and residue from drilling and sedimentary rocks and formations, commonly known as sand pumpings. Williams rock series See: igneous-rock series rockshaft 2679

A shaft made for sending down rock for filling the stopes, etc., generally kept nearly full, the rock being trammed away as needed. Standard, 2 rock sharp A mineral expert. Mathews rock shovel A machine for loading broken rock. See also: shovel loader Nelson rock silk A silky variety of asbestos. Fay rockslide a. A slide involving a downward and usually sudden and rapid movement of newly detached segments of bedrock sliding or slipping over an inclined surface of weakness, as a surface of bedding, jointing, or faulting, or other preexisting structural feature. The moving mass is greatly deformed and usually breaks up into many small independent units. Rockslides frequently occur in high mountain ranges, as the Alps or Canadian Rockies. AGI b. The mass of rock moving in or moved by a rockslide. Also spelled rock slide. Syn: rock slip rock slip See: rockslide rock slope A slope driven through rock strata. rock soap See: mountain soap rock spar Material filling fracture cleavages in coal, consisting of nonclay mineral matter, probably deposited from solution, and sand, usually calcite or gypsum. AGI rock splitter

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In the stonework industry, one who splits large blocks of building granite, marble, and sandstone into slabs or smaller blocks, by drilling holes into the stone and then driving wedges into them until the stone breaks along the line of drilled holes. Also called rock breaker; rock driller. See also: rock driller; quarryman. DOT rock stress a. See: rock pressure b. The problem of determining the stresses that exist in the Earth's crust has long been of interest to engineers and geologists. Many mining problems are directly concerned with stresses that may cause mine openings to collapse. Two phases of occurrence of rock stresses are important: (1) the stresses existing in the rock before the excavation of the mine openings; i.e., the free field stress, and (2) the indirect stresses caused by the mine openings. See also: free field stress rock temperature a. The formational temperature at depth. The rate of increase of temperature with depth (the geothermal gradient) is highly variable over the earth, but averages 25 degrees C/km. AGI b. The temperature of the rock in a mine. Lewis rock tunnel A tunnel, drift, or crosscut driven through rock, usually connecting one coalbed with another; also through barren rock in metal mines. rock turquoise A matrix of turquoise with small grains of turquoise embedded in it. Fay rock type a. One of the three major groups of rocks: igneous, sedimentary, metamorphic. AGI b. A particular kind of rock having a specific set of characteristics. It may be a general classification, e.g., a basalt, or a specific classification, e.g., a basalt from a particular area and having a unique description. AGI c. The megascopically recognizable ingredients of coal rock; i.e., vitrain, clarain, durain, and fusain. See also: banded ingredient rock waste See: debris rock weight

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S. Afr. One (short) ton (0.9 t) of rock in place equals about 12 ft3 (0.34 m3 ). Horizontally, therefore, the weight of an ore reserve covering a claim over a stoping width of 3 ft (0.91 m) is 64,000 ft2 X 3 ft / 12 ft3 /st = 16,000 st (14,500 t) at 100% payability. In case the vein dips downward, the resulting amount must be divided by the cosine of the angle of dip. Beerman Rockwell hardness test A method of determining the relative hardness of metals and case-hardened materials. The depth of penetration of a steel ball (for softer metals) or of a conical diamond point (for harder metals) is measured. See also: scleroscope hardness test Rockwell machine Trade name for an apparatus that measures the hardness of metals and alloys, in which a diamond-pointed cone is pressed under a specific load into the metal. The relative resistance to penetration (Rockwell hardness) is indicated by a number (Rockwell number) on a dial. The operation is called a Rockwell hardness test. Syn: Rockwell tester Rockwell tester See: Rockwell machine rockwood See: mountain wood rock wool See: asbestos rod bit A noncoring bit designed to fit a reaming shell that is threaded to couple directly to a drill rod, thus eliminating the core barrel in blasthole drilling. Also called blasthole bit. Long rod clearance See: clearance rod coupling Name for a double-pin-thread coupling used to connect two drill rods together. Long 2682

rod damp See: safety clamp rodding a. Cleaning and descaling of piping by means of scrapers attached to series of jointed rods. Pryor, 3 b. Eng. The operation of fixing or repairing wooden cage guides in shafts. c. In metamorphic rocks, a linear structure in which the stronger parts, such as vein quartz or quartz pebbles, have been shaped into parallel rods. Whether the structure is formed parallel to the direction of transport or parallel to the fold axes has been debated. AGI rod dope Grease or other material used to protect or lubricate drill rods. Also called rod grease. Syn: gunk rod drag The rubbing of the rods or drill string on the sidewalls of the borehole. Syn: rod friction rod drop The distance of slump or slag in a long string of rods when released from the drill chuck. Long rod elevator See: elevator; elevator plug. rod friction a. The drag created in the flow of the drilling liquid by contact and constrictional effects created by the inside surface of the drill rods and couplings. CF: skin friction; wall friction. Long b. See: rod drag rodingite A massive dense buff to pink rock typically rich in grossular garnet and calcic pyroxene, and enveloped in serpentinite. Epidote, vesuvianite, and other calcium-rich minerals are commonly present. It is formed by metasomatic alteration of a protolith that, in many cases, was a dike rock, as shown by preservation of structures. The name was applied by Bell in 1911. AGI 2683

Rodio-Dehottay process A method of shaft sinking by the freezing method. It is based on the direct cooling effect of expanding highly compressed carbon dioxide in the freezing pipes. See also: Koch freezing process rodlike Refers to elongate crystals. CF: acicular; equant; tabular; lathlike. rodman a. A person who uses or carries a surveyor's leveling rod. Also called rodsman. Standard, 2 b. See: staff man rod mill a. A mill for rolling rod. ASM, 1 b. A mill for fine grinding, somewhat similar to a ball mill, but employing long steel rods instead of balls to effect the grinding. ASM, 1 rod millman One who grinds clinker, phosphate rock, or ore in a revolving cylinder partially filled with round steel rods; also, he or she tests a product for fineness by observing how much material is left on sieve of determined mesh, and regulates amount of material entering the mill accordingly. DOT rodney Eng. A rude platform near the shaft's mouth for a night fire. Fay rod plug See: elevator plug rod proof A test specimen taken from the melt on an iron rod. ASTM rod pull a. The number of borehole round trips made in a unit of time. Long b. The number of lengths of drill rod (two or more standard 10-ft lengths coupled together and handled and stacked as unit lengths) needed to reach the bottom of the borehole. Long 2684

rod puller Various mechanisms, essentially a double-acting air-actuated piston equipped with a rodgripping device, commonly used to pull drill rods from a borehole in underground workings where a small drill without a hoist is used, or from drill rods stuck in a drill hole. Syn: air rod puller Long rod reaming shell A reaming shell designed to be coupled directly to a drill rod. See also: rod bit rod reducing bushing A pin-to-box sub used to connect one size rod in a string to a larger or smaller size. Long rod reducing coupling A pin-to-pin adapter used to connect a rod of one size to one of a larger or smaller size. Long rods a. Eng. Vertical or inclined timbers for actuating pumps. b. Long bars of Swedish iron of the toughest quality, for boring through rocks, etc. c. See: cage guide rod sag The bending of a long drill string due solely to its own weight. Also called rod slack. Syn: sag rod shaft The mine shaft containing the pump rods. rod shell See: rod reaming shell rod slack See: rod sag rod slap

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The impact of drill rods with the sides of a borehole, occurring when the rods are rotating. Syn: whip rod snap A sudden acceleration in rotational speed of the rods followed immediately by a sudden return to the former speed. Long rod spear A long, tapered, four-sided fishing tool. Used to remove a lost drill rod or other tubular piece of drill equipment from a borehole. Long rod stand The length of drill rod handled and stacked in the tripod or derrick as a unit piece during round trips. Also called offtake. See also: double; treble. Long rod stock Round steel rod. Nichols, 1 rod string The drill rods coupled to form the connecting link between the core barrel and bit in the borehole and the drill machine at the collar of the borehole. Long rod stuffing box An annular packing gland fitting between the drill rod and the casing at the borehole collar. It allows the rod to rotate freely but prevents the escape of gas or liquid under pressure. Esp. utilized when drilling with counterflow; when drilling in an area where a high hydrostatic pressure or flow of water may be encountered, as in drilling a cover or pilot hole; or when drilling up holes from an underground drill site. Long roentgen equivalent man A unit of ionizing radiation, equal to the amount that produces the same damage to humans as 1 R of high-voltage X-rays. Abbrev. rem. McGraw-Hill, 1 roentgenite See: roentgenite roentgenogram 2686

A photograph made with X-rays. Syn: roentgenograph; radiograph. Webster 3rd roentgenograph See: roentgenogram Roesing lead pump An automatic apparatus for discharging lead from the kettle; used in the Parkes process. Fay Roesing wires Wires suspended in a dust chamber to assist in settling and condensing dust and fumes from furnace gases. Fay Roesler process A process for separating copper, and in part silver, from gold by fusing with sulfur or with antimony sulfide, obtaining copper or silver sulfide. Fay roestone A fine-grained oolite resembling the roe of a fish. See: oolite Fay Rohbach solution An aqueous solution of mercuric barium iodide with a density of 3.5 g/cm3 ; used for separating minerals by density. Roheisenzunder process A method that makes use of an airstream at a pressure of 4 atmospheres for atomizing molten pig iron into minute particles. The molten metal falling into an air stream formed by an annular slit in a steel cyclone is atomized, the particles falling into a water bath and subsequently dried. Osborne Rohrbach solution An aqueous solution of mercuric barium iodide; clear, yellow liquid; very refractive; sp. gr., 3.5. Used in separating minerals by their specific gravity and in microchemical detection of alkaloids. CCD, 2 roke 2687

Prov. Eng. A vein of ore. A variation of rake. See: rake roll a. An elongate protrusion of shale, siltstone, or sandstone (locally limestone) from the roof into a coal seam, causing a thinning of the seam and sometimes replacing it almost entirely. CF: cutout commonly overlain by a thin coal stringer. AGI b. An elongate upheaval of the floor material into a coal seam, causing thinning of the seam. Syn: horseback c. Various minor deformations or dislocations of a coal seam, such as washouts, small monoclinal folds, or faults with little displacement. AGI d. In veins and other types of ore deposit, a thickening or an arcuate change in dip in the orebody. e. See: roll orebody f. A rotating cylinder used to support or guide a portion of conveyor belt. g. One of two cylinders or grooved rollers between which material is drawn, for reducing its thickness, as the finished rolls of a rolling mill. BS, 11 h. The appearance of other types of mineral deposits in places where the bed or vein thickens or thins. Mason i. A roughly cylindrical distribution of uranium mineralization occurring usually in the Salt Wash Sandstone. There is some question whether the feature is structural or sedimentary. j. An inequality in the roof or floor of a mine. NEMA, 1 k. S. Wales. The drum of a winding engine. l. Cast-iron or steel cylinder, used to break coal and other materials into various sizes. Applies to the type of crushing machinery in which the ore or coal is broken between cylindrical rolls, either plain or fitted with steel teeth, revolving toward each other, drawing the material in between the crushing peripheries, which rotate in a vertical plane. Fay; Liddell m. In powder metallurgy, a machine used to apply pressure progressively to form a compact. See also: crushing roll; ribbed roll; smooth roll; want; washout. Rolfe roll compacting The progressive compacting of metal powders by the use of a rolling mill. ASTM roll crusher A type of secondary or reduction crusher consisting of a heavy frame on which two rolls are mounted. These are driven so that they rotate toward one another. Rock fed in from above is nipped between the moving rolls, crushed, and discharged at the bottom. See also: double-roll crusher Newton, 1 rolled metal Refers to metal, such as silver or stainless steel, which has been clad with a precious metal and rolled to reduce the thickness of the coat. USBM, 7 rolled plate

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A thin plate of gold spread upon a layer of base metal by soldering the metals in the bar and then rolling the whole out into plate, forming a thinner plate of gold than that of the ware known as gold-filled. Also called rolled gold. Fay rolled-steel joist An I-beam made from a single piece of steel passed through a hot rolling mill. Hammond roller a. A broad pulley or wheel fixed to the floor, roof, or sides of roadways to prevent a haulage rope running against the ground that would cause excessive friction and wear of rails and sleepers. Nelson b. A component part of a roller chain in which it may serve only to reduce frictional loss occurring as the chain negotiates sprockets. Rollers may also serve as the rolling support for the chain and the load being conveyed. c. A heavy vehicle used for compacting soil, earth fill, and top layers of spoil dumps to increase the density and bearing capacity of the material. Nelson roller bearings Hard steel cylinders in bearings that have very low frictional resistance. Hammond roller bit a. A rotary boring bit consisting of two to four cone-shaped, toothed rollers that are turned by the rotation of the drill rods. Such bits are used in hard rock in oil well boring and in other deep holes down to 5,000 m and more. See also: tricone bit; drag bit. Nelson b. A type of rock-cutting bit used on diamond and rotary drills. The bit consists of a shank with toothed, circular, or cone-shaped cutter parts affixed to the head of the bit in such a manner that the cutters roll as the bit is rotated. Generally used for drilling 10-cmsize or larger holes in soft to medium-hard rocks, such as shale and limestone. Usually noncoring and not diamond set. Also called cone bit. CF: noncoring bit See also: rock bit; roller rock bit. Syn: roller cone bit; roller-cutter bit; rolling cutter bit; toothed roller bit. Long roller chain a. Generally, any sprocket-driven chain made up of links connected by hinge pins and sleeves. Nichols, 1 b. Specif., a chain whose hinge sleeves are protected by an outer sleeve or roller that is free to turn. Nichols, 1 roller cone bit See: roller bit 2689

roller-cone core bit A type of roller bit with cutter cones arranged to cut an annular ring leaving an uncut section in the center as core. Long roller conveyor A series of rolls supported in a frame over which objects are advanced manually, by gravity or by power. See also: controlled velocity roller conveyor; el conveyor; gravity conveyor; herringbone roller conveyor; hydrostatic roller conveyor; portable conveyor. Syn: gravity roller conveyor roller-cutter bit See: roller bit roller gate Hollow cylindrical crest gate controlling a dam spillway. See also: sector gate; sliding gate. Hammond roller grip A device for clutching a traction cable between grooved sheaves or rollers. rollerman In mining, a laborer who inspects idler rollers or pulleys over which a cable passes along inclined haulageways, oiling or greasing rollers, resetting displaced ones, and repairing or replacing damaged ones. Also called pulley man; pulley repairer; pulley repairman; roller repairman; sheaveman; wheelman. DOT roller repairman See: rollerman roller rock bit A rotary bit fitted with two or more hardened steel or tungsten-carbide-tipped rollers of cylindrical or conical form. Variously known as two-cone bit, three-cone bit, four-cutter bit, etc. See also: roller bit roller screen See: revolving screen 2690

rolley man See: incline repairman roll feeder a. A smooth, fluted, or cleated roll or drum that rotates to deliver packages, objects, or bulk materials. b. A circular drum, plain or ribbed, rotating on a horizontal shaft and situated at the mouth of a bunker or hopper to control the rate of discharge of material therefrom. BS, 5 roll-front orebody A roll orebody of the Wyoming type, which is bounded on the concave side by oxidized altered rock typically containing hematite or limonite, and on the convex side by relatively reduced altered rock typically containing pyrite and organic matter. See also: roll orebody rolling and quartering A sampling method in which the sample is formed into the requisite flat heap by placing it upon a rubber or other smooth sheet and, by lifting the corners of this sheet in proper rotation, rolling the material to and fro. The resultant heap is then quartered and alternate quarters are taken. This method is used with smaller bulk and smaller sizes of material. Truscott rolling cradle A rod slide equipped with rollers that contact the rods and over which the rods roll on being pulled or lowered into an angle borehole. Long rolling cutter bit See: roller bit rolling plant A rolling mill or establishment for rolling metal into forms. Standard, 2 rolling resistance a. The sum of the external forces opposing motion over level terrain. Carson, 1 b. The tractive resistance caused by friction between the rails and wheels, which forms the major resistance on level tracks. See also: tractive force 2691

rolling-up curtain weir A type of frame weir, the frame of which remains upright, being rolled up from the bottom. Hammond roll jaw crusher A crusher of the same general type as the Blake or Dodge, but the moving jaw has a rolling instead of an oscillating motion. Liddell rollman In beneficiation, one who tends rolls that are used to crush ore, which has already been broken into small pieces in a crusher, to a fine size preparatory to the extraction of the valuable minerals. DOT roll operator One who operates conical rolls that separate stone from clay, preventing machine from jamming by regulating flow of clay into it. DOT roll orebody A uranium and/or vanadium orebody in a sandstone lens or layer, which cuts across bedding in sharply curving forms, commonly C-shaped or S-shaped in cross section. Two types can be distinguished: the Colorado Plateau type, named in 1956, and the Wyoming type, named in 1962. Roll orebodies of the Colorado Plateau type are of highly variable geometry, with their longest dimension in plan view parallel to the axes of buried sandstone lenses representing former stream channels, and surrounded by a wide halo of reduced (altered) rock. Orebodies of the Wyoming type are crescent-shaped in cross section and typically form in relatively thick, tabular, or elongate sandstone bodies, with the tips of the crescent thinning and becoming tangent to mudstone layers above and below. See also: roll-front orebody roll scale See: mill scale roll screen A screen consisting of a number of horizontal rotating shafts, fitted with elements arranged to provide screening apertures. BS, 5 roll sulfur 2692

a. A commercial name for sulfur that has been purified and cast into rolls or sticks. Standard, 2 b. See: brimstone Roman cement See: pozzolana cement romanechite A monoclinic mineral, (Ba,H2 O)Mn5 O10 ; rare as single crystals; commonly intergrown with other manganese oxides. Formerly called psilomelane, a term now reserved for mixtures. CF: hollandite romanite A yellow, black, or green amber from Romania. Also spelled rumanite. English Roman ocher A native ocher of a deep orange-yellow color. Standard, 2 Roman pearl A hollow sphere of opalescent glass with its interior coated with essence d'orient and then filled with wax. romeite An isometric mineral, (Ca,Fe,Mn,Na)2 (Sb,Ti)2 O6 (O,OH,F) ; stibiconite group; forms clusters of minute yellow octahedra. Syn: weslienite romometer An instrument for measuring changes in vertical height and lateral movements of the roof relative to the floor at the coal face. Syn: roof movement meter Nelson rondle The crust or scale that forms upon the surface of molten metal in cooling. Fay roentgen The unit of exposure dose of X-ray or gamma-ray radiation. One roentgen is an exposure dose of X-ray or gamma-ray radiation such that the associated corpuscular emission per 2693

0.001293 g of air produces, in air, ions carrying 1 electrostatic unit of quantity of electricity of either sign. Designated by the symbol R. Also spelled roentgen. NCB roentgenite Minute wax-yellow to brown, trigonal pyramidal crystals, intergrown with synchysite, parisite, and bastnasite, from Narsarsuk, Greenland. From X-ray and optical data, the composition is deduced as Ca2 (Ce,La)3 (CO3 )5 F3 . Also spelled roentgenite. Spencer, 5 roof a. The rock immediately above a coal seam. It is commonly a shale and is often carbonaceous in character and softer than similar rocks higher up in the roof strata. The roof shale may contain streaks and wisps of coaly material, which tends to weaken the deposit. Roof in coal mining corresponds to hanging wall in metal mining. See also: roof stone Nelson b. In mine timbering there are two classifications of roof, the immediate roof and the main roof. The immediate roof lies directly over the coal and may be a single layer or several layers of rock material of the same, or different consistencies, and from a few inches to several feet in thickness. This roof requires timbering to support it as the coal is removed. The main roof is the roof above the immediate top, and may vary from a few feet to several hundred, or even thousands of feet in thickness. This roof is generally controlled by leaving pillars of solid coal that will support its weight. Kentucky c. The country rock bordering the upper surface of an igneous intrusion. CF: floor roof bolt a. A long steel bolt inserted into walls or roof of underground excavations to strengthen the pinning of rock strata. It is inserted in a drilled hole and anchored by means of a mechanical expansion shell that grips the surrounding rock at about 4 ft (1 m) spacing and pins steel beams to the roof. b. Syn: rock bolt c. Current roof bolting consists of steel rods, 5/8 to 1 in (2 to 2.5 cm) or more in diameter and 3 to 8 ft (1 to 2.5 m) in length, anchored by a mechanical expansion shell, resin grout, or a combination of both. Grouted bolts may be fully or partially grouted. A steel plate, sometimes in combination with wooden headers or steel straps, fits tightly between the bolthead and mine roof or rib. roof bolter In bituminous coal mining, one who reinforces roofs of mine haulageways, side drifts, and working places with metal or timber to prevent rock and slate falls. Also called raise driller; stoperman; stoperperson; timberman. DOT roof bolting

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A system of roof support in mines. Boreholes usually from 3 to 12 ft (1 to 4 m) long are drilled upward in the roof, and bolts of 5/8 to 1 in (2 to 2.5 cm) or more in diameter are inserted into the holes and anchored at the top by a split cone, mechanical anchor, or resin grout. The bolts are put up in a definite pattern. The idea is to clamp together the several roof beds to form a composite beam with a strength considerably greater than the sum of the individual beds acting separately. See also: slot-and-wedge bolt; pin timbering; rock bolting. CF: strata bolt roof control The scientific study of the behavior of rock undermined by mining operations and the most effective measures of controlling movements and failure. The subject is comprehensive, including the systematic measurement of the movement of strata and the forces and stresses involved. An attempt is made to correlate data with rock types and the type of excavation. See also: rock mechanics roof cut A machine cut made in the roof immediately above the seam. A roof cut is sometimes made in a soft band of dirt over the coal, which gives increased height in thin seams. The cut is made with a turret coal cutter. Nelson roof cutting It is a common occurrence to hear miners talk of gas cutting the roof and causing it to weaken; however, this condition is seldom encountered. There are some seams where gas does cut the roof, generally where top coal is left in gassy seams. The most common cause of roof cutting is its exposure to air. Gunite or painting of the top helps a condition of this kind. Kentucky roof drill Various hydraulically operated mechanized machines designed to install roof bolts. Two workers can install up to 200 bolts per shift. Units are available in both standard and special design to satisfy requirements in different mines. Best, 1 roof-framy A roof that is tenacious and when allowed to fall breaks down in large blocks or frames of stone. Peel roofing The wedging of a loaded wagon or horse against the top of an underground passage. Fay 2695

roofing hole In West Wales, a small, steeply inclined stone drivage from a lower to an upper coal seam or for exploration in disturbed ground. Syn: roof-up Nelson roof jack A screw- or pump-type extension post used as a temporary roof support. BCI roof layer a. Uniformly thick layer of rock supported or clamped at the edges by pillars. Obert b. A layer of combustible gas under the roof of mine workings. BS, 8 roof movement meter See: romometer roof pendant A downward projection of country rock into an igneous intrusion. CF: cupola roof pressure The pressure that the overlying rocks exert on the support of mine workings. See also: ground pressure roof rock Rock forming the ceiling of a cave passage, underground chamber, mine opening, etc. AGI roof shale The layer or seam of shale occurring immediately above the Pittsburgh coal seam. Because of its friable nature, this shale or slate is taken down in most mining operations. Rice, 2 roof station A survey station fixed in the roof of a mine roadway or working face. BS, 7 roof stone Scot. The stone immediately above a coal seam. See also: roof Fay 2696

roof stringer Used in a weak or scaly top in narrow rooms or entries that have short life. It is done by placing lagging bars running parallel with the working place above the header. It has limited uses because of necessary additional height and because its weight rests on the center of the header. See also: stringer roof testing In the simple testing of the roof, it is struck by a hammer or a heavy object. A loose roof will give off a dull or hollow sound compared with a solid top, which has a clear ring. Good roof that has a clear ringing sound is called "bell top." Also known as sounding, sounding the roof, sounding the top, and jowling. Syn: top testing roof-testing tool Usually a wooden pole with a metallic ball at the upper end. roof-to-floor convergence The deformation of the coal or ore pillars is estimated by monitoring the closure of the entry. This roof-to-floor convergence is generally measured with a tube extensometer, to an accuracy of 0.001 in (25.4 mu m), or a tape measure, to an accuracy of 0.01 ft (3.048 mm). Measurements are repeatedly taken as the mining geometry changes. SME, 1 roof-up See: roofing hole roof work A term applied to a vein worked overhead. room a. A place abutting an entry or airway where coal or ore has been mined and extending from the entry or airway to a face. b. A wide working place in a flat mine corresponding to a stope in a steep vein. A chamber. CF: stope c. A heading or short stall. room-and-pillar Said of a system of mining in which typically flat-lying beds of coal or ore are mined in rooms separated by pillars of undisturbed rock left for roof support. See also: bord-andpillar working; County of Durham system. Syn: heading and stall 2697

room-and-pillar mining In coal and metal mining, supporting the roof by pillars left at regular intervals. Lewis room-and-pillar with waste filling See: overhand stoping room boss In bituminous coal mining, a miner who inspects the working face in working places (rooms) to determine whether mining operations are being carried on properly and safety regulations are being observed. Also called wall boss. DOT room conveyor a. Any conveyor that carries coal from the face of a room toward the mouth. Normally, a room conveyor will deposit its coal into a car or another conveyor at the mouth of the room, but occasionally it will dump into a cross conveyor at some point between the face and the mouth. Jones, 1 b. See: underground mine conveyor room entry Any entry or set of entries from which rooms are turned. A panel entry. room neck A short passageway from the mine entry to the room in which a miner works. room system with caving See: bord-and-pillar rooseveltite A monoclinic mineral, BiAsO4 ; monazite group; at Santiaguillo, Bolivia. root clay See: underclay root deposit A lode or vein from which alluvial cassiterite or gold may have been derived. 2698

rooter a. A towed scarifier; sometimes used to break up a hard surface and prior to the use of bulldozers in removing overburden at quarries and opencast pits. A heavy-duty ripper. Nelson b. A towed machine equipped with teeth, used primarily for loosening hard soil and soft rock. Nichols, 2 root hook A very heavy hook designed to catch and tear out big roots when it is dragged along the ground. Nichols, 1 root-mean-square value The root-mean-square value of an alternating current or voltage. It is the square root of the mean value of the squares of the instantaneous values taken over a complete cycle. When an alternating current or voltage is specified, it is almost invariably the root-meansquare value that is used. Also used of quantities that alternate over longer periods, for example, a month or year. Also known as effective value. Abbrev., R.M.S. CTD rope and button conveyor A conveyor consisting of a rope with disks or buttons attached at intervals, the upper flight running in a trough. The coal or other material is dropped into the trough, and the conveyor either is actuated by the weight of the coal in the trough when the trough is inclined forming a retarding conveyor, or moves the coal along the trough where the gradient is insufficient or adverse. In the one case a brake is provided; in the other, the sprockets are actuated by a motor. Zern rope core An important component of stranded ropes is the core, which may be either of fiber or of wire. In winding ropes it is generally made of manilla, sisal, or hemp. The function of the core is to support the strands and prevent them from bearing hard against one another. An even more important function is as a store for lubricant for the interior of the rope, and during manufacture it is saturated with lubricant. Sinclair, 5 rope cutter See: hook tender rope diameter The diameter of a steel wire rope is the maximum obtainable measurement across the outer edges of the strands. The size of fiber ropes is usually specified by their 2699

circumference. Modern steel wire winding ropes are large and heavy and may be 2-1/4 in (5.7 cm) in diameter for a moderately deep shaft. Nelson rope driver In bituminous coal mining, a foreperson who looks after the haulage cable and the equipment of trains of cars by which coal is hauled from the mine. The rope driver superintends the attaching of cars to cable by clipper and directs movement of the cable by signaling a slope engineer through a buzzer system. DOT rope driving The transmission of power by means of rope gearing, as distinguished from belt drive. Crispin rope drum Any drum, powered or otherwise, on which rope is wound; e.g., mining machine rope drums, room hoist rope drums, etc. Jones, 1 rope fastening The most suitable fastening between a wire rope and its socket is a white metal capping. Haulage ropes are generally doubled back on themselves around a steel thimble and secured with bulldog clips. Hammond rope guide Steel rope suspended in a vertical shaft to prevent excessive swinging of the cages or skips. Eight rope guides are generally used for the shaft, four for each cage, and two additional rubbing ropes are installed to prevent possible collision between the cages or skips. The ropes are suspended from girders fixed on the safety hook catch-plate platform and kept taut in the shaft by means of weights in the shaft bottom sump. The clearances between the cages, and also between the cage corners and the shaft wall, should be about 12 in (30.5 cm). See also: fixed guides Nelson rope haulage a. Means of moving loaded and empty mine cars by use of wire rope; generally used on steep inclines where use of electric mine locomotives is inefficient. BCI b. Any transportation system employing a steel wire rope to haul the mine cars or trams. See also: direct-rope haulage; main-and-tail haulage; tail-rope haulage. Nelson rope haulage systems 2700

Systems of rope haulage may be classified as (1) self-acting or gravity planes; (2) engine planes; (3) tail-rope haulage; (4) endless-rope haulage; and (5) aerial tramways, which are frequently considered by themselves, since they are not applied to transporting material underground. Lewis rope lay That length of rope in which one strand makes one complete revolution about the core. rope plucking The sudden jerking or twitching of a haulage rope due to the rope laps slipping to a smaller diameter on the drum. A severe plucking of a rope may be felt faintly more than 800 yd (725 m) distance from the engine. See also: overhaul rope rider An employee whose duty it is to see that cars are coupled properly, and to inspect ropes, chains, links, and all coupling equipment. A trip rider. See also: brakeman rope roof bolt A steel wire rope, with wedge heads fixed to its ends, used instead of the normal steel rod in roof bolting. Also known as cable bolting. The rope has a diameter of about 7/8 in (2.2 cm) and a length from 15 to 20 ft (4.5 to 6 m). Nelson rope socket A drop forged-steel device, with a tapered hole, which can be fastened to the end of a wire cable or rope and to which a load may be attached. It may be either the open- or closed-end type. Long ropeway a. A line or double line of suspended ropes, usually wire, along which articles of moderate weight may be transported on slings, either by gravity or power; much used in mining districts for transportation to watercourses or to railway lines. An aerial tramway. Standard, 2 b. See: aerial ropeway Ropp furnace A long reverberatory furnace with a series of plows or rakes that are drawn over the hearth by a continuous cable, moving the ore steadily from the feed to the discharge end. Fay 2701

roquesite A tetragonal mineral, CuInS2 ; chalcopyrite group; at Charrier, Allier, France. rosasite a. A monoclinic mineral, 4[(Cu,Zn)2 (CO3 )(OH)2 ] ; forms green to blue spherules in oxidized zones of zinc-copper-lead deposits. b. The mineral group glaukosphaerite, kolwezite, mcguinnessite, nullaginite, rosasite, and zincrosasite. Roeschen method A combustible-gas drainage method utilizing controlled drainage from the coal seams as they are being mined. This method, which is also known as the pack cavity method, was devised to extract gas from the mined-out areas of advancing longwall mining systems by leaving corridors or cavities at regular intervals in the pack. Virginia Polytechnic roscherite A monoclinic and triclinic mineral, Ca(Fe,Mn)2 Be3 (PO4 )3 (OH)3 .2H2 O . roscoelite A monoclinic mineral, K(V,Al,Mg)2 (AlSi3 )O10 (OH)2 ; mica group; soft; a source of vanadium. rose beryl The morganite variety of beryl. rose bit A hardened steel or alloy noncore bit with a serrated face to cut or mill out bits, casing, or other metal objects lost in the hole. Also used to mill off the rose-bit dropper on a Hall-Rowe wedge. Also called mill; milling bit. CF: junk mill rose copper See: rosette copper rose diagram A circular diagram for plotting strikes (with or without dips) of planar features, such as joints, faults, and dikes; so named because clusters of preferred orientations resemble the petals of a rose. AGI 2702

roselite a. A monoclinic mineral, Ca2 (Co,Mg)(AsO4 )2 .2H2 O ; roselite group; forms a series with wendwilsonite; dimorphous with roselite-beta; perfect cleavage. b. The mineral group brandtite, roselite, wendwilsonite, and zincrosasite. rose of cracks The system with radial cracks issuing from the center of the hole as a result of the tangential stresses. Langefors rose opal A variety of opaque common opal having a fine red color. CMD rose quartz Crystalline quartz with a rose pink color, due probably to titanium in minute quantity. The color is destroyed by exposure to strong sunlight. Used as a gem or an ornamental stone. See also: Bohemian ruby Fay rose steel A steel that shows a peculiar fracture and texture in the interior, different from that near the surface. Standard, 2 rose topaz The yellow-brown variety of topaz changed to rose pink by heating. These crystals often contain inclusions of liquid carbon dioxide. CMD rosette A radially symmetric, sand-filled crystalline aggregate or cluster with a fancied resemblance to a rose; formed in sedimentary rocks by barite, marcasite, or pyrite. See also: petrified rose rosette copper Disks of copper (red from the presence of suboxide) formed by cooling the surface of molten copper through sprinkling with water. Also called rose copper. Fay rosette texture A flowerlike or scalloped pattern of a mineral aggregate. AGI 2703

rose vitriol Cobalt sulfate. See also: bieberite vitriol. Standard, 2 rosickyite A monoclinic mineral, S (gamma sulfur); dimorphous with sulfur. Syn: gamma sulfur rosin a. The hard, amber-colored residue left after distilling off volatile oil from pine pitch. API, 1 b. To melt a resin and apply a coat to the right-handed threads of heated rod couplings; the coating sets when cooled, which permits the rods to be used in the same manner as left-hand-threaded rods in fishing operations. Also called rosining. Long rosin blende A yellow variety of zinc blende, ZnS. When dark in color it is called blackjack. rosined joints Drill-rod or casing couplings to which hot rosin was applied and that were joined before the rosin cooled. Long rosing The act or process of milling a metal object in a borehole with a rose bit. Long rosin jack A yellow variety of sphalerite. Also called resin jack, rosin blende, rosen zinc. CF: blackjack Rosin-Rammler equation An equation relating to fine grinding: for most powders that have been prepared by grinding, the relationship between R, the residue remaining on any particular sieve, and the grain size in micrometers (x) is exponential: R = 100e-bxn, where e is the base of the natural logarithm and b and n are constants. (Dodd, 1964) rosin tin A reddish or yellowish variety of cassiterite. Also spelled resin tin. rosin zinc 2704

Sphalerite of a rosiny appearance. Hess rosite a. See: anorthite b. An impure muscovite as alteration product. rosiwal analysis In petrography, a quantitative method of estimating the volume percentages of the minerals in a rock. Thin sections of a rock are examined with a microscope fitted with a micrometer that is used to measure the linear intercepts of each mineral along a particular set of lines. This method is based on the assumption that the area of a mineral on an exposed surface is proportional to its volume in the rock mass. AGI rosolite A rose-pink variety of grossulatire garnet. Also called landerite and xalostocite. From Xalostoc, Morelos, Mexico. English Ross and Welter furnace A multiple-deck roasting furnace of the annular type; used in Germany. Fay Ross feeder Mechanism for control of rate of feed of coarse ore in the primary and secondary crushing system. Several heavy loops of chain lie above and bear on ore that rests in the delivery chute at just above its natural angle of repose. When the shaft from which the loops are suspended is rotated by its small motor, ore slides under control. Pryor, 3 Rossie furnace An American variety of hearth for the treatment of galena, differing from the Scotch hearth in using wood as fuel, working continuously, and having hollow walls, to heat the blast. Fay Rossi-Forel intensity scale A scale for rating earthquake effects. Devised in 1878 by de Rossi (Italy) and Forel (Switzerland). No longer in general use, having been supplanted by Wood and Neumann's Modified Mercalli intensity scale of 1931. AGI rosthornite 2705

A brown to garnet-red resinous material forming lenticular masses in the coal of Carusthia. AGI rotameter A tapered float rises or falls in a transparent tube in accordance with the velocity of the rising liquid. Variations include spinning floats and magnetic or radioactive ones for use with opaque fluids. Rate-of-flow indicator. Pryor, 3 rotap Laboratory screen shaker widely used in screen sizing analysis. Up to seven 8-in round screens are nested on the appliance and given a shaking, rotary, and tapping motion. Pryor, 3 rotary See: rotary table; rotary-drill rig. rotary bit As used in a broad sense by drillers, a roller bit. Long rotary boring A system of boring, using usually hollow rods, with or without the production of rock cores. Rock penetration is achieved by the rotation of the cutting tool. The method is used extensively in exploration, particularly when cores are required. It is the usual method in oil well boring with holes from 6 to 18 in (15 to 45 cm) in diameter. See also: boring; diamond drilling; rotary drill. Nelson rotary breaker A breaking machine for coal, rock, or minerals. It consists of a trommel screen with a heavy cast steel shell fitted internally with lifts that progressively raise and convey the coal and stone forward and break it. As the material is broken the undersize passes through the apertures, so that excessive degradation does not occur. See also: trommel; Bradford breaker. Nelson rotary bucket drill A rotary-type drill on which a rotary bucket is fastened to the kelly bar. The bucket is equipped with a hinged bottom, which has straight-edged cutting blades or teeth. When rotated by the kelly bar, the bucket loads from the bottom; when filled, it is withdrawn from the hole and dumped by unlatching the bottom. Holes 30 to 250 cm in diameter can 2706

be drilled with this machine in soft, boulder-free ground. Also called bucket rig; dryhole digger; rathole rig. See also: bucket drill rotary compressor A compressor designed for a delivery pressure of 100 psi (690 kPa) and ranging in capacity from 60 to 300 ft3 /min (2.1 to 8.5 m3 /min). See also: air-conditioning process rotary drier A drier in the shape of an inclined rotating tube used to dry loose material as it rolls through. ACSG, 2 rotary drill Broadly, various types of drill machines that rotate a rigid, tubular string of rods to which is attached a bit for cutting rock to produce boreholes. The bit may be a roller cone bit, a toothed or fishtail drag bit, an auger bit, or a diamond bit. See also: core drill; rock drill. CF: diamond drill; shot drill. rotary-drill cuttings The chips and pulverized rock produced by the abrasive and chipping action of a drag, roller bit, or diamond bit when used on a diamond- or rotary-drill machine to drill a borehole. CF: cuttings rotary drilling The hydraulic process of drilling that consists of rotating a column of drill pipe, to the bottom of which is attached a drilling bit, and during the operation, circulating down through the pipe a current of mud-laden fluid, under pressure, by means of special slush pumps. The drilling mud and cuttings from the bit are forced upward and outside the drill pipe to the surface. CF: cable-tool drilling rotary drill motor The space available in the casing of a pneumatic rotary rock or coal drill is necessarily limited and precludes the use of a reciprocating engine. The power unit used instead is similar in design to the vane compressor. The rotor runs at a very high speed, between 3,500 rpm and 4,000 rpm, and this is reduced by gearing to give a drill spindle speed of about 650 rpm. rotary-drill rig

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A rotary drill complete with accessory tools and equipment necessary to drill boreholes. Long rotary dump An apparatus for overturning one or more mine cars simultaneously to discharge coal. They may rotate either 180 degrees or 360 degrees . BCI rotary dump car A standard small car in which the car body, of about 2 yd3 (1.5 m3 ) capacity, is mounted on a turntable in the car frame. The car body may be swung by hand to dump over either side or either end. Pit and Quarry rotary dumper A steel structure that revolves a mine car and discharges the contents, usually sideways, into a bunker or onto a screen. Nelson rotary excavator Earth-moving machine with vertical wheel that carries digging buckets peripherally. These loosen soil and deliver to short conveyor loader, the assembly being mounted on crawler track. Capacity up to 5,000 st/h (4,500 t/h). Also called bucket wheel excavator. Pryor, 3 rotary fault See: rotational fault rotary feed table a. A feeder comprising a horizontal rotating circular plate mounted under the mouth of a hopper and arranged with an adjustable plow to control the rate of flow of material over the edge of the plate. BS, 5 b. See: disk feeder rotary furnace Horizontally mounted cylinder rotating between trunnions through which gas or oil flame is introduced. Pryor, 3 rotary-percussive drill A drilling machine that operates as a purely rotary machine to which is added a percussive action. The specially designed rotary-percussive drilling bit not only gives a 2708

greater penetration rate, but is also able to operate longer without deterioration of the cutting edges. A disadvantage is the great size of the air-operated machine, which is usually mounted on a carriage. Nelson rotary percussive drilling A method of drilling in which repeated blows are applied to the bit, which is continually rotated under power. BS, 12 rotary pump A positive-displacement pump in which the liquid-propelling parts are cams, gears, impeller wheels, etc., rotating within a case, as distinguished from those pumps that move liquids by means of the to-and-fro motion of a piston within a cylinder. CF: centrifugal pump Long rotary screen a. A screen for sizing aggregate and similar material; it is a pierced rectangular plate bent into a cylinder. Hammond b. See: trommel rotary shot drill a. Any rotary drill used to drill blastholes. Long b. See: seismograph drill rotary smelter Any of the cylindrical smelters that depend on slow rotation about a horizontal axis for agitation of the molten mass. See also: smelter ASTM rotary sorting table A circular plate conveyor to effect a preliminary grading of coals and removal of stone by hand. A screened-out fraction of the run-of-mine coal is delivered to the table by chute from a conveyor. As the stream of coal revolves on the table, the various grades of coal and the dirt are raked into positions where they are diverted by plows into chutes. The operators are positioned on the inner and outer edges of the table and the coal is not handled but only raked. Syn: circular grading table rotary table a. The geared rotating table that propels the kelly and the drill stem when drilling a borehole with an oilfield-type rotary rig. Also called rotary; table; turntable. Long b. The mechanism used in some forms of rotary drilling to rotate the drilling column. BS, 9 2709

rotary vane feeder A rotor of cylindrical outline with radial, spaced plates or vanes rotating on a horizontal axis, for controlling the flow of bulk materials. rotary vibrating tippler A tippler designed to overcome the tendency for coal or dirt to stick to the bottom of the tubs or mine cars. When the tippler is in the inverted position, the car rests upon a vibrating frame that gives it a high-speed vertical jolting motion, which frees any material tending to stick inside the car. Nelson rotating casing screw conveyor A screw conveyor in which the tubular casing rotates at a different speed or in an opposite direction to the conveyor screw. See also: screw conveyor rotational fault A fault on which rotational movement is exhibited; a partial syn. of hinge fault. CF: hinge fault; scissor fault. Syn: rotary fault rotational flow Turbulent flow involving all parts of a moving liquid. rotational movement Apparent fault-block displacement in which the blocks have rotated relative to one another, so that alignment of formerly parallel features is disturbed. CF: translational movement AGI rotational shear One of four types of slope failure. Failure by rotational shear produces a movement of an almost undisturbed segment along a circular or spoon-shaped surface and occurs in comprehensive, uniform material. This material would not be affected by geological planes of weakness. Failure of this type can occur from causes that either increase the shear stresses or decrease the shear strength of the material. Woodruff rotational slide A slide of homogeneous earth or clay in which the slip surface of failure closely follows the arc of a circle. Nelson 2710

rotational transformation An isochemical phase change involving only a shift in angle of chemical bonds, e.g., beta-quartz to alpha-quartz. CF: phase transformation; displacive transformation; reconstructive transformation; dilational transformation. rotational wave See: S wave rotation firing Crushing a small piece of rock with a first explosion, and timing other holes to throw their burdens toward the space made by that and other preceding explosions. Also called row shooting. Nichols, 1 rotation recorder An instrument for measuring any slight rotation of a bridge support under load. See also: spread recorder rotch See: rotche rotche S. Staff. A soft and moderately friable sandstone. Also called roach; rotch; roche. rothoffite A brown variety of andradite garnet. Rot I plate See: gypsum plate; selenite plate. rotobelt filter Drum-type vacuum filter in which the membrane is a belt, which leaves the drum at discharge point and is returned via pulleys. This arrangement facilitates washing of filter cake from both sides, also discharge. Pryor, 3 roto finish 2711

A tumbling method using special chips and chemical compounds. Osborne rotor Any unit that does its work in a machine by spinning and does not drive other parts mechanically. Nichols, 1 rotor steel process A steelmaking process using the principle of rotation as in the Kaldo process. It has two lances; one above the bath surface uses low-pressure oxygen to burn carbon monoxide from the bath, while the other blows oxygen onto the bath at high pressure to obtain similar fast oxidation as in the L.D. steel process. Nelson rotten reef S. Afr. Decomposed, soft country rock found in connection with auriferous conglomerates. rottenstone A soft, light, earthy substance consisting of fine-grained silica resulting from the decomposition of siliceous shale-on limestone. It is used for polishing. CF: diatomite rough a. Highly fractured, broken, or cavey ground. Long b. An uncut gemstone. Pertaining to an uncut or unpolished gemstone; e.g., a rough diamond. AGI roughbacks Term used in the dimension stone industry for ends of blocks that are used as byproducts. rough diamond A diamond in its natural state. Long rougher cell Flotation cells in which the bulk of the gangue is removed from the ore or coal. rough ground Highly fractured, fragmented, or cavey rock formations. Long 2712

roughing Upgrading of run-of-mill feed either to produce a low-grade preliminary concentrate or to reject valueless tailings at an early stage. Performed by gravity on roughing tables, or in flotation in rougher circuit. See also: cleaning roughing hole A hole to receive slag from a blast furnace, or molten iron when it is undesirable to let it run into pigs. Standard, 2 roughing mill a. A metal disk charged with an abrasive, used for the first work in grinding gems. Standard, 2 b. A set of roughing rolls. Standard, 2 roughing rolls The rolls of a train that first receive the pile, ingot, bloom, or billet, and partly form it into the final shape. Also called breaking-down or roughing-down rolls. Fay roughing tool The ordinary tool used by machinists for removing the outer skin and generally for heavy cuts on cast iron, wrought iron, and steel. Crispin rough stone a. See: rough diamond b. A gemstone that has not yet been polished or cut. roughway Corn. A quarry term to designate a direction along which there is no natural cleavage in a rock. See also: cleaving way; quartering way. round a. A planned pattern of drill holes or series of shots intended to be fired either simultaneously or with delay periods between shots; also, the muck pile obtained when the round is blasted. b. A round generally consists of cut holes, easers, and trimmers. See also: drill-hole pattern; shot firing in rounds. Nelson c. The holes drilled for blast, the advance from a blast, or the ore, or rock from a single blast. Ballard d. A blast including a succession of delay shots. Nichols, 1 e. In the operation of a blast furnace, one complete charge of ore, coke, and limestone. Henderson 2713

roundabouts See: circuits round-face bit A bullnose bit; also, any bit the cutting face of which is rounded, such as a single- or double-round nose bit. Long round-headed buttress dam A mass concrete dam constructed of parallel buttresses thickened at the upstream end until they conjoin. See also: multiple-arch dam Hammond round hook A hook that has a smooth inner surface and will slide along a chain. Nichols, 1 rounding tool A forming or swaging tool having a semicylindrical groove; a blacksmith's swage or collar tool. Standard, 2 round kiln See: beehive kiln roundstone a. A rounded rock fragment of any size larger than a sand grain; a group name for pebbles, cobbles, or boulders -- any or all of these. Stokes b. A diamond crystal with an arched facet. Hess c. A term proposed by Fernald (1929) for any naturally rounded rock fragment of any size larger than a sand grain (diameter greater than 2 mm), such as a boulder, cobble, pebble, or granule. See also: cobblestone round strand rope A rope composed of a number of strands, generally six in number, twisted together or laid to form the rope around a core of hemp, sisal, or manilla, or, in a wire-cored rope, around a central strand composed of individual wires. Sinclair, 5 round trip

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The process of pulling the drill string from a borehole, performing an operation on the string (such as changing a bit, emptying the core barrel, etc.), and then rerunning the drill string into the borehole. See also: trip row a. Corn. Coarse, undressed tin ore; refuse from stamping mills. Arkell b. N. Staff. A seam or bed of coal. c. A line of points in a lattice. See: lattice roweite An orthorhombic mineral, Ca2 Mn2 B4 O7 (OH)6 ; forms a series with fedorovskite; forms light brown laths; at Franklin, NJ. rowlandite An amorphous mineral, Y4 FeSi4 O14 F2 (?) ; massive; dark-green where fresh; becomes brick red on alteration. row shooting In a large blast, setting off the row of holes nearest the quarry face first, and other rows behind it in succession. Nichols, 1 Roxite A nonpermitted gelatinous explosive; medium strength, high density, and good water resistance. Used in tunneling in nongassy mines in rocks of medium hardness. Nelson royal barren Solution overflowed from first ion-exchange column in a series that is receiving and stripping pregnant uranium liquor; contains some uranyl. Pryor, 3 royalty a. A lease by which the owner or lessor grants to the lessee the privilege of mining and operating the land in consideration of the payment of a certain stipulated royalty on the mineral produced. Ricketts b. See: overriding royalty c. Ownership of mineral rights under restricted terms. Wheeler, R.R. d. Eng. The mineral estate or area of a colliery, or a portion of such property. A field of mining operations. e. The landowner's share of the value of minerals produced on a property. It is commonly a fractional share of the current market value (oil and gas) or a fixed amount per ton (mining). See also: take royer 2715

In foundry work, centrifugal belt thrower. Short length of conveyor belting travels at 2,000 to 4,000 ft/min (600 to 1,200 m/min) and conditions molding sands by discharging them vigorously so as to mix and partially dry them. Similar arrangement also used in forming storage piles and loading small material to ships. Pryor, 3 rozenite a. A monoclinic mineral, FeSO4 .4H2 O . b. The mineral group including aplowite, boyleite, ilesite, rozenite, and starkeyite. rubasse a. Fr. A crystalline variety of quartz containing, distributed through it, spangles of hematite that reflect a ruby red. Also spelled rubace. Also known as Ancona ruby; Mont Blanc ruby. Standard, 2; Fay b. Quartz, stained red in cracks to imitate ruby. Hess rubber a. Guide; binder; conductor. Mason b. Derb. Fine scythestone; micaceous sandstone. Arkell c. A gold-quartz amalgamator in which slime is rubbed against amalgamated copper surfaces. d. A bucking iron or bucking hammer. A broadhead hammer. Fay e. A building brick made from a sandy clay and lightly fired so that it can be readily rubbed to shape for use in gaged work. The crushing strength of such a brick is about 1,000 psi (6.9 MPa). Dodd rubber-bushed couplings Two flanged hubs, one equipped with rubber-bushed holes, the other equipped with pins that mesh with the rubber bushings. To prevent excessive wear, the rubber bushings are bushed with nonferrous bushings, which provide satisfactory contact and wearing surfaces. Pit and Quarry rubber conveyor belt A conveyor belt consisting of a central stress-bearing carcass for transmitting power enclosed in rubber or PVC covers to protect the carcass from abrasion and atmospheric changes. The carcass usually consists of plies of cotton duck fabric, but other constructions used are cotton cords, steel cables, and woven fabrics of synthetic fibers, such as rayon, nylon, Orlon, Dacron, fiberglass, and asbestos. The covers are furnished in various thicknesses and qualities of rubber or PVC compounds. rubber-lined pipes Pipes prepared for handling corrosive liquids in such processes as acid leaching. Also, pumps and impellers handling ore pulps. See also: hydraulic stowing pipe 2716

rubberstone A sharp-gritted Ohio or Indiana sandstone used for sharpening shoe knives; also known as shoe stone. rubber-tired haulage The underground use of tractors and dump truck haulage, of battery or diesel type, and battery-driven shuttle cars. See also: trackless tunneling rubbing bed In quarrying, a bed consisting of a circular disk of cast iron of varying diameters, rotating on a vertical axis. Marble slabs or blocks held on the surface of this rotating disk, to which sand and water are applied, are worn down to desired dimensions and smoothness. AIME, 1 rubbing stone a. Stone used for rubbing, smoothing, or sharpening; in particular for facing building stones by removing toolmarks. Arkell b. A block of fine-grained abrasive, such as corundum, for the stoning of vitreous enamel. Dodd rubbing surface The total area of a given length of airway; i.e., the area of top, bottom, and sides added together, or the perimeter multiplied by the length. rubble a. A loose mass of angular rock fragments, commonly overlying outcropping rock; the unconsolidated equivalent of a breccia. CF: talus b. Loose, irregular pieces of artificially broken stone as it comes from a quarry. Syn: rubblestone rubble concrete Concrete in which large blocks of stone, roughly squared, are placed and arranged roughly in courses, so that they break joint both horizontally and vertically. The stones are placed with not less than 6 in (15 cm) of space between them so that the concrete may be properly rammed. Care is taken that all voids are filled with concrete. Nelson rubbleman In the quarry industry, a foreman who directs and supervises the work of drilling and splitting stone. DOT 2717

rubble masonry Uncut stone, used for rough work, foundations, backing, etc. Crispin rubblerock See: breccia rubblestone See: rubble rubbly reef Aust. A vein much broken up. rubellite A pink gem variety of elbaite. Syn: red schorl ruberite See: cuprite rubicelle A yellow or orange-red variety of spinel; an aluminate of magnesium. CF: ruby spinel rubidium A soft, silvery-white, metallic element of the alkali metal group, closely resembling potassium. Symbol, Rb. Widely distributed in small quantities in nature. Obtained commercially from lepidolite and from potassium minerals. Forms amalgams with mercury and alloys with gold, cesium, sodium, and potassium. Has been considered for use in space vehicles, and for use in thermoelectric generators. Handbook of Chemistry and Physics, 3 rubinblende Miners' term for the red silver sulfides pyrargyrite, proustite, and miargyrite. Syn: ruby blende rubinglimmer See: lepidocrocite 2718

Ruble hydraulic elevator A device by which coarse material in placer gravel is separated from the fines and elevated onto a dump. ruby The red gem variety of corundum, the color due to the presence of chromium in the structure. CF: sapphire ruby alumina An abrasive similar to white alumina except ruby red in color because of the presence of chromic oxide. ACSG, 2 ruby arsenic An early name for realgar. See also: ruby sulfur ruby blende a. A reddish variety of sphalerite. Syn: ruby zinc b. See: rubinblende ruby cat's eye A girasol ruby with a chatoyant effect. CF: sapphire cat's eye ruby copper See: cuprite ruby copper ore See: cuprite ruby mica An old syn. for goethite. Fay ruby sand A red-colored beach sand containing garnets, as at Nome, AK. AGI ruby silver 2719

Dark ruby silver is pyrargyrite, and light ruby silver is proustite. Dana, 4 ruby spinel A red gem variety of spinel. CF: almandine ruby; balas ruby; rubicelle. ruby sulfur See: realgar Standard, 2; Fay ruby tin A red variety of cassiterite. ruby zinc Miners' term for transparent red sphalerite or zincite. Syn: ruby blende rudaceous Said of a sedimentary rock composed of a significant amount of fragments coarser than sand grains; pertaining to a rudite. The term implies no special size, shape, or roundness of fragments throughout the gravel range, and is broader than pebbly, cobbly, and bouldery. Also said of the texture of such a rock. AGI rudite A general name used for consolidated sedimentary rocks composed of rounded or angular fragments coarser than sand (granules, pebbles, cobbles, boulders, or gravel or rubble); e.g., conglomerate, breccia, and calcirudite. The term is equivalent to the Greekderived term, psephite. Etymol: Latin rudus, crushed stone, debris, rubble. See also: lutite; arenite. AGI Ruggles-Coles dryer Rotary drier or kiln, in which material is worked through a horizontal cylinder counter to drying or heating gas blown through by fan. Pryor, 3 ruin Eng. A term occasionally employed in familiar description for certain minerals whose sections or cut faces exhibit the appearance of ruined buildings, as ruin agate, ruin marble, etc. Fay ruin agate 2720

A brown variety of agate displaying on polished surfaces markings that resemble the outlines of ruined buildings. ruin aragonite Brecciated Mexican onyx (aragonite). Schaller ruinform Minerals having the form or appearance of ruins. rule of approximation Applicable to placer mining locations and entries upon surveyed lands to be applied on the basis of 10-acre (4-ha) legal subdivisions. Ricketts ruling grade The grade that determines tonnage that can be handled by a single locomotive over a particular engine district. Urquhart ruling gradient See: limiting gradient rumanite See: romanite Rumford's photometer A photometer consisting of a rod standing vertically in front of a white screen on which are cast shadows of it by the two light sources whose intensities are to be compared. When the shadows are of equal darkness the ratio of the intensities of the sources equals the square of the ratio of their distances from the screen. CTD run a. A branching or fingerlike extension of the feeder of an igneous intrusion. Typically spread laterally along several stratigraphic levels. AGI b. A flat irregular ribbonlike orebody following the stratification of the host rock. AGI c. The direction in which a vein of ore lies. d. A caving in of a mine working. e. Soft ground is said to run when it becomes mud and will not hold together or stand. f. The escape of any flowing material into a tunnel area; it may be sand, gravel, or mud. Stauffer g. See: grain h. The length of feed or the advance made by a bit in drilling before it becomes necessary to rechuck the 2721

rods or empty the core barrel. CF: pull i. A round trip in drilling. Long j. Continuous production, the operation of equipment between major repairs. k. A test made of a process or material. runaround a. A passage driven in the shaft pillar to enable workers to pass safely from one side of the shaft to the other side. See also: bypass Fay b. A conveyor in the form of a circuit as distinguished from a shape in which the carrying and return runs travel substantially the same path. runaway The uncontrolled downward rush of trams when the haulage rope breaks or becomes detached while the set is being hauled up an incline. Nelson runaway switch Catch point or other automatic diverting switch gear; acts when a mine car runs downgrade or out of control by diverting it to a siding. Pryor, 3 runback a. To drill slowly downward toward the bottom of the hole when the drill string has been inadvertently or deliberately lifted off-bottom during a rechucking operation. Long b. To retract feed mechanism to its starting position when rechucking. Long runback water Scot. Water from a set of pumps that is run back and pumped up again to keep the pump from going "on air" while the other pumps are at work. run dry To drill without circulating a drilling fluid or mud. CF: dry block Long runic texture Suggested by Johannsen as an alternative to graphic texture, since the intergrown quartz and feldspar resemble runic characters. CTD run in a. To lower the assembled drill rods, core barrel, and bit, or other types of pipe, casing, or drill string into a borehole. Long b. To drill the first few inches slowly at the 2722

beginning of a core run or when collaring a borehole. Long c. The initial period of operation of any mechanism during which the component parts seat themselves. Jackson, 1 run-in table See: entry table. run levels To survey an area or strip to determine elevations. Nichols, 1 runner a. Bearer or carrier girder, beam, or bar. Mason b. A steel-shod poling board, driven into unbroken but loose ground as excavation proceeds. See also: cross poling c. See: driller d. A fault slip. Fay runner box A distribution box that divides the molten metal into several streams before it enters the mold cavity. ASM, 1 runners Vertical timber sheet piles driven to protect an excavation from collapse. See also: guide runner; cross poling. Hammond runner stick A slightly tapering, round stick, used as a pattern for the opening through which molten metal is to be poured into the mold. Standard, 2 running a. The act or process of operating a drill, drilling with a bit, or lowering casing, drivepipe, or drill string into a borehole. Long b. Earth and rock that will not stand, esp. when wetted, and falls, flows, or sloughs into a borehole or a workplace in a mine. Long running block See: traveling block running dry 2723

The act of drilling without circulating a drilling fluid. Long running ground a. Insecure or easily caved wall of excavation. Pryor, 3 b. Ground that is incoherent, for example, soils, sand, peat, moss, or waterlogged material. It may be semiplastic or plastic, such as wet clays. All such deposits deform readily under pressure, and relief is obtained by squeezing into openings, such as mine workings. The miner uses the term running ground to indicate the difficulty of support and sometimes of danger. See also: forepoling; quicksand; mud rush. Nelson running kiln A lime kiln that is fed from above and delivers continually below. Standard, 2 running lift Light mine pump used in sinking, which can be raised or lowered in shaft as required. Pryor, 3 running measures Eng. Sand and gravel containing much water. running off In founding, the opening of the taphole of a blast furnace and allowing of the molten metal to flow out to the molds. Standard, 2 running rope A flexible rope of 6 strands, 12 wires each, and 7 hemp cores. Hunt running sand a. An unconsolidated sand. See also: run b. Quicksand. Fay running sheave A sheave used as a single-pulley traveling block. Long runoff

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a. That part of precipitation appearing in surface streams. AGI b. The collapse of a coal pillar in a steeply pitching seam, caused either naturally or by a small shot in connection with pillar robbing. The pillar is said to have run off. Fay runoff coefficient The percentage of precipitation that appears as runoff. The value of the coefficient is determined on the basis of climatic conditions and physiographic characteristics of the drainage area and is expressed as a constant between zero and one (Chow, 1964). Symbol: C. AGI runoff pit Catchment to which spillage can gravitate should it be necessary to dump the contents of mill machines such as classifiers, thickeners, and slurry pumps. Provided with a reclaiming pump so that the contents can be returned to the appropriate part of the flow line. Pryor, 3 run of lode Corn. The direction or course of a lode. run-of-mill Ore finally accepted by a mill for treatment, after waste and dense-media rejection. Original mined ore (run-of-mine) is ore as severed and hoisted. Syn: mill-head ore run-of-mine a. The raw mined material as it is delivered by the mine cars, skips, or conveyors and prior to treatment of any sort. See also: pithead output Nelson b. Average grade of ore produced from a mine. New South Wales c. Said of ore in its natural, unprocessed state; pertaining to ore just as it is mined. AGI runout a. The unintentional escape of molten metal from a mold, crucible, or furnace. ASM, 1 b. In mineral processing, the dumping of pulp before the contained solids pack down and choke a stalled mechanism in the event of a breakdown or a power failure. Pryor, 3 runout fire A forge in which cast iron is refined. Fay run-to-waste 2725

Drill cuttings that are not collected or saved as a sludge sample and are allowed to collect in the sump; also, the return drill-circulation fluid not returned to a sump for recirculation. Long Ruoss jig A jig used chiefly on tin dredges to treat the undersize from the main revolving screen. It differs from the Harz jig in that there is no longitudinal division and the screening compartment extends over the whole surface of the jig; the plungers are located in the hutch below the screen are set in a vertical plane and reciprocate horizontally. Harrison rupture Deformation characterized by loss of cohesion. Frequently flow grades into rupture, with a progressive loss of cohesion, until complete separation occurs. See also: fracture rupture envelope See: Mohr envelope rupture factor The term is used with reference to brittle materials; i.e., materials in which failure occurs through tensile rupture rather than through excessive deformation. For a member of given form, size, and material, loaded and supported in a given manner, the rupture factor is the ratio of the fictitious maximum tensile stress at failure, as calculated by the appropriate formula for elastic stress, to the ultimate tensile strength of the material as determined by a conventional tension test. Roark rupture line See: Mohr envelope rupture strength The differential stress that a material sustains at the instant of breaking, or rupture. The term is normally applied when deformation occurs at atmospheric confining pressure and room temperature. AGI rupture zone The region immediately adjacent to the boundary of an explosion crater characterized by excessive in-place crushing and fracturing where the stresses produced by the explosion exceeded the ultimate strength of the medium. CF: plastic zone 2726

rush a. A stampede of prospectors and miners into a new discovery area. b. A place where gold is found in abundance. Standard, 2 rush gold See: rusty gold russellite Corn. A tetragonal mineral, Bi2 WO6 ; a yellow alteration product with native bismuth and wolframite. Russell process A metallurgical process similar to the Patera process, except that cuprous sodium hyposulfite is used in addition to the sodium hyposulfite. Liddell Russia iron A high-grade, smooth, glossy sheet iron, not liable to rust; once made by a process that was long a secret with Russian manufacturers. The sheets were subjected to severe hammering in piles with powdered charcoal between them. Standard, 2 Russian crystal A colorless variety of gypsum. rust a. A corrosion product consisting of hydrated oxides of iron. Applied only to ferrous alloys. ASM, 1 b. A mixture of iron filings, ammonium chloride, and sometimes sulfur, moistened and placed between iron surfaces, where it hardens by oxidation, and forms a solid joint called a rust joint. Standard, 2 c. An English term for a black shale discolored by ocher. AGI rustler In anthracite and bituminous coal mining, a general term applied to any worker who looks after the haulage system, performing the necessary work by which mine cars are raised and lowered to and from the mine surface. May be designated according to job, as clipper; rollerman. DOT rustless process 2727

A process for the manufacture of stainless steels in an electric furnace that uses a chrome ore as a source of chromium with or without the addition of silicoferrochromium, conjointly with stainless steel scrap. The hearth of the furnace is lined with chromite bricks. Osborne rusty gold Cal. Free gold, that does not readily amalgamate, the particles being covered with a siliceous film, thin coating of oxide of iron or manganese, etc. Syn: rush gold rute In mining, threadlike veins of ore. Standard, 2 ruthenium A hexagonal mineral, Ru . rutherfordine An orthorhombic mineral, UO2 (CO3 ) ; radioactive; earthy yellow; secondary. rutilated quartz Sagenitic quartz characterized by enclosed needles of rutile. CF: fleches d'amour; sagenite. Syn: Venus hairstone See also: sagenitic quartz rutile a. A tetragonal mineral, TiO2 , in which titanium replaces iron; trimorphous with anatase and brookite; prismatic; in amphibolites, ecologites, granite pegmatites, veins, and placers; a source of titanium; also a gemstone. Syn: red schorl; titanic schorl. See also: titanium dioxide; zircon group. b. The mineral group argutite, cassiterite, paratellurite, plattnerite, pyrolusite, rutile, and stishovite. R wave See: Rayleigh wave Rziha's theory A mine subsidence theory that is a variant or extension of the vertical theory. In this theory, allowance is made for movements beyond the undermined area, but the dip of the beds is considered to be of little or no influence. Rziha maintained that if rock is 2728

undercut, it will stay undisturbed if cohesion exceeds gravity and will fall if gravity exceeds cohesion. Briggs

S Sabalite Trade name for banded variscite; may be banded vashegyite and natrolite; used as a gem stone. Syn: Trainite sabkha a. A supratidal environment of sedimentation, formed under arid to semiarid conditions on restricted coastal plains just above normal high-tide level. It is gradational between the land surface and the intertidal environment. Sabkhas are characterized by evaporite-salt, tidal-flood, and eolian deposits, and are found on many modern coastlines, e.g., Persian Gulf, Gulf of California. See also: tidal flat. AGI b. Any flat area, coastal or interior, where, through deflation and evaporation, salts crystallize near or at the surface. AGI c. In the rock record, a sabkha facies may be indicated by evaporites, absence of fossils, thin flat-pebble conglomerates, stromatolitic laminae, desiccation features such as mud cracks, and diagenetic modifications, for example, disrupted bedding, dissolution and replacement phenomena, and dolomitization. The sabkha environment may have been significant in the formation of certain petroleum and sulfide-mineral deposits. Etymol: Arabic. Also spelled: sabkhah. Syn: sebkha sabugalite A monoclinic mineral, HAl(UO2 )4 (PO4 )4 .16H2 O ; autunite group; pseudotetragonal; forms crusts of minute yellow platy crystals in pegmatites at Sabugal, Portugal. sacrificial anodes The anodes used in cathodic protection against corrosion. Hammond sacrificial protection Reducing the extent of corrosion of a metal in an electrolyte by coupling it to another metal that is electrochemically more active in the environment. ASM, 1 saddle

2729

a. A ridge connecting two higher elevations; a low point in the crestline of a ridge. A minor upfold along the axis of a syncline; a minor downfold along the axis of an anticline. b. A gold-bearing quartz vein of anticlinal form, occurring esp. in Australian saddle reefs. See also: saddle reef c. A peculiar formation of sand slate found in shale or sand rock may be surrounded by soapstone. The under or exposed side of a saddle looks like natural rock, but its upper side is smooth, having no particular bond with the sand rock with which it is embedded, and it is liable to fall out of its place, a fall, however, producing no other derangement of the surrounding parts of the room from which it falls. Ricketts d. A hump-shaped piece of roof rock with a smooth back, insecurely attached to adjacent strata. Also called saddleback. Hudson saddleback a. Eng.; Scot. A roll or undulation in the roof or pavement of a seam. See also: saddle b. A hill or ridge having a concave outline along its crest. AGI saddle back reef A lode or reef bent archwise. Anticline. Pryor, 3 saddle block In a dipper shovel, the boom swivel block through which the stick slides when crowded or retracted. Nichols, 1 saddle reef a. A mineral deposit associated with the crest of an anticlinal fold and following the bedding planes, usually found in vertical succession, esp. the gold-bearing quartz veins of Australia. Syn: saddle vein. AGI b. Aust. A bedded vein that has the form of an anticline; an inverted saddle has the form of a syncline. See also: saddle c. An opening at the crest of a sharp fold in sedimentary rocks, occupied by ore. Bateman, 2 saddle vein See: saddle reef safety As applied to mining, means freedom from danger, injury, or damage. Kentucky safety belt a. A worker's belt attachable to some fixed object to safeguard against falls. b. A protective belt or harness with remote anchorage, worn by a worker, for example, a 2730

quarryman, working on a face at height. Since the belt allows a drop of about 6 ft (2 m) a shock absorber is provided. Nelson c. A belt worn by a derrickman or tripodman to prevent injury due to accidental falls from the top of a derrick. Long d. A belt to which tools are attached to prevent risk of their falling into machines, thickeners, etc. Pryor, 3 safety car Any mine car or hoisting cage provided with safety stops, catches, or other precautionary devices. Fay safety catch A safety appliance that transfers the weight of the cage onto the guides if the winding rope breaks. Nelson safety chain A chain used across openings to mantrips and personnel carriers to prevent miners from falling out of a moving vehicle. Syn: breakaway chain safety check A check valve to slow the excessive travel speed of a piston in a hydraulic cylinder. Long safety clamp Any of several types of rod clamps used at the collar of a borehole to hold the drill rods while they are being pulled or lowered. Also called alligator; automatic spider; floor clamp; foot clamp. Long safety department A department that deals with all aspects of mine safety and safety training. See also: safety engineer safety detaching hook A device that releases automatically the hoisting rope from a cage in the event of an overwind. See also: detaching hook safety door A spare or extra door fixed ready for use in a roadway in the event of damage to the existing ventilation door. The safety door is also positioned so that it can be employed in 2731

any emergency, for example, explosions or fires. The door may be of steel construction. Nelson safety engineer An employee whose job is to inspect all possible danger spots in the mine and plant; to cooperate with safety committees in various parts of the organization; to keep informed upon safety literature and to carry on a perpetual educational campaign among workers; to cooperate with agencies such as the U.S. Mine Safety and Health Administration, the U.S. Bureau of Mines, the National Safety Council, and State bureaus and inspectors; to head all rescue work, first-aid instruction courses, and safety-first meetings; and to draw up and enforce a written code of minimum safety requirements for all work at the mine and plant. safety explosive Explosive that requires a powerful initial impulse and therefore may be handled safely under ordinary conditions. Bennett safety factor a. The ratio of breakage resistance to load. Nichols, 1 b. See: factor of safety c. Ratio of breaking stress to working stress. Obert safety fuse A train of powder enclosed in cotton, jute yarn, and waterproofing compounds; used for firing a cap containing the detonating compound, which in turn sets off the explosive charge. The fuse burns at the rate of 2 ft/min (0.6 m/min). Used mainly for small-scale blasting in quarries and metal mines. See also: blasting fuse; capped fuse; premature blast. Nelson safety gate An automatically operated gate placed at the top of a mine shaft, or at landings, to guard the entrance, to prevent anyone from falling into the shaft. Fay safety glass Most commonly a sandwich of plastic between two sheets of glass; i.e., laminated safety glass. Also called tempered safety glass; wire safety glass. See also: Triplex glass safety hat

2732

a. A cap or hat with a hard crown worn by miners, will resist blows against it. BCI b. A hat or cap made of rigid material, designed for the protection of the heads of workers. If worn in a mine equipped with electricity, the material should be electrically nonconducting. Also called safety cap. c. See: tin hat safety hook a. A hoisting hook with a spring-loaded latch that prevents a load from accidentally slipping off the hook. Long b. A self-acting detachable hook on a mine cage, which acts in the event of an overwind. See: safety detaching hook c. A safety catch in a mine hoist. Standard, 2 safety inspector See: mine inspector safety joint A coarse-threaded joint in the head of a double-tube core barrel. If the core barrel becomes lodged in the borehole, the safety joint, inner tube, and core can be removed by backing off at the safety joint, thereby facilitating the subsequent fishing job. Long safety lamp In gassy mines, a lamp of an approved type, which is relatively safe to use in atmospheres that may contain flammable gas. Latterly, the term tends to be restricted to naptha-fueled safety lamps, which are issued to mine inspection personnel and used for combustible gas tests. See also: bonnet; cap lamp; Davy lamp; flame safety lamp; electric cap lamp. Nelson safety-lamp keeper See: lampman safety-lamp mine In Great Britain, a coal mine in no part of which below ground is the use of lamps or lights other than permitted lights lawful. Nelson safety latch A latch provided on a hook or elevator to prevent it from becoming detached prematurely. CF: safety hook safety light 2733

A spring-tensioned aluminum pole (of two sections) with a holder to hold a flashlight in a horizontal position with an adjustable screw aligned with the push button switch of the flashlight. If there is conversion of the mine roof (back), the adjustment screw will depress, putting on the light to warn a miner in the area. Sometimes accompanied by a conversion gauge (measures in thousandths). See also: guardian angel safety lock An offset swivel coupling that supports the weight of the rods when whipstocking. Long safety platform a. A platform built in a derrick as a safe working place for workers who must be up the derrick to handle elevators, casing, drill rods, etc. Long b. A platform with a hinged-door opening, over a shaft while being sunk, esp. where blasted materials are hoisted with a muck bucket. After the bucket is hoisted, the hinged door is closed to prevent any material from falling back onto workers in the shaft. safety post A timber placed near the face of working places to afford protection for the workers at the face. It must be set like a line timber and with equal care. Kentucky safety powder A term used for short-flame explosives before the introduction of permissible explosives. Fay safety rope winch A cable-winding device anchored at the upper grade of an inclined face and having its cable attached to the head of the coal cutter or cutter loader to assist overcoming frictional resistance of the cutter or loader while in operation against the grade. safety stop a. An appliance to stop or control cars near the shaft at the pit bottom or at the top of incline haulages. Nelson b. On a hoisting apparatus, a check by which a cage or lift may be prevented from falling. Standard, 2 c. An automatic device on a hoisting engine designed to prevent overwinding. Fay safety switch A switch that provides shunt protection in blasting circuits between a blast site and the switch used to connect a power source to the blasting circuit. CFR, 5 2734

safety tools a. Nonsparking tools made of beryllium-copper alloy for use in explosive atmospheres. Hess b. A tool such as a catching hook, a grappling tong, a fish head, or a bell screw, for recovering broken boring tools, picking up material, etc., at the bottom of boreholes. Fay safety valve A pressure-relief valve. Long safflorite a. Essentially, a diarsenide of cobalt but usually with a considerable amount of iron, and rarely, a small amount of nickel. Syn: cobalt lollingite b. An orthorhombic mineral, 4[CoAs2 ] ; loellingite group; dimorphous with clinosafflorite; metallic; tin-white tarnishing to dark gray; sp gr, 7.4; in hydrothermal veins. safreiro See: mucker sag a. A depression in a coal seam, mine floor, or roof. AGI b. A depression produced by downwarping of beds on the downthrown side of a fault such that they dip toward the fault. AGI c. The difference between the sagging path a conveyor belt actually takes due to the imposed load of material and its own weight, and the theoretical plane tangent to the top of the supporting idler rolls. d. See also: rod sag sag belt tension The minimum tension in any portion of the carrying run of belt necessary to prevent excessive sag of the belt between belt idlers. sag bolt Bolts installed at intersections to measure roof sag. A sag bolt is a 12-ft (3.5-m) unit put in without a bearing plate. It is securely anchored in the 12-ft horizon with the aid of a heavy nut, and extends about 2 in (5 cm) from the hole. Three 1/2-in (1.3-cm) strips of colored pressure-sensitive tape are wrapped around the extending section of the bolt, beginning with green at the roof line, then yellow and red. The color bands provide a simple, economical means of detecting roof sag at a glance. Coal Age, 3 sag correction 2735

A tape correction applied to the apparent length of a level base line to counteract the sag in measuring tape. Hammond sagenite a. An acicular variety of rutile in reticulated twin groups. b. See: rutilated quartz; Venus hairstone. Etymol: Latin "sagena" large fishing net. Adj: sagenitic. sagenitic Occurring as needles or plates intersecting in a gridlike or grill-like manner. CF: acicular sagenitic quartz Transparent quartz containing acicular rutile, tourmaline, goethite, actinolite, or other mineral. See also: Thetis hairstone; Venus hairstone; rutilated quartz. sagger A coarse fireclay, often forming the floor of a coal seam, so called because it is used for making saggers or protective boxes in which delicate ceramic pieces are placed while being fired. Etymol: corruption of "safeguard." Also spelled: seggar. Syn: sagre sagging moment A bending moment that produces concave bending at midspan of a simply supported beam, generally termed a positive bending moment. It is the opposite of a negative or hogging moment, which would occur at the supports. Hammond sag meter See: closure meter sag pipe A term proposed as a substitute for inverted siphon. Seelye, 1 sagponds Ponds occupying depressions along active faults, owing to uneven settling of the ground. sagre See: sagger 2736

sag structure A general term for load casts and related sedimentary structures. sag tower A pair of floating lightweight sheaves, which give support, at a suitable point, to the ropes leading away from the winding drums. The sheaves are located at a point about one-third of the length of rope between the drum and winding pulleys, measured from the drum. A sag tower suppresses rope oscillation and dampens out the rhythmic swing of the rope. Nelson sahlinite A monoclinic mineral, Pb14 (AsO4 )2 O9 Cl4 ; forms aggregates of thin yellow scales; at Laangban, Sweden. sahlite Alternate spelling of salite. Saint Stephen's stone A white or grayish chalcedony with tiny red spots so close together that the appearance at a distance is a uniform rose-red. Hess sal See: sial salable coal Total coal mine output less tonnage rejected or consumed during preparation for market. Pryor, 3 salable minerals A legal term that for Federally owned lands, defines mineral commodities that are sold by sales contract from the Federal Government. These are generally construction materials and aggregates such as sand, gravel, cinders, roadbed, and ballast material. The applicable statute is the Mineral Materials Sale Act of 1947, as amended (30 USC 602604, 611-615). SME, 1 salable output 2737

The total tonnage of clean coal produced at a mine as distinct from pithead output. It is the tonnage of coal as weighed after being cleaned and classified in the preparation plant. Nelson salamander A solid mass of iron, frequently weighing many tons, that is deposited and substantially replaces the firebrick hearth in the bottom of a blast furnace after long periods of operation. Syn: bear salamanders' hair See: asbestos sal ammoniac An isometric mineral, NH4 Cl ; a volatile white crystalline salt forming encrustations around volcanic vents. Syn: salmiak Salamon-Munro formula A coal pillar design formula that predicts the strength of coal pillars based on a survey of failed and standing coal pillars in South Africa. The coal pillar strength is predicted from coal pillar height and width specifications combined with empirical constants developed from fitting the design equation to 125 case studies. SME, 1 salamstone A pale-red or blue variety of gem corundum in small transparent hexagonal prisms in Sri Lanka. salar A term used in Southwestern United States and in the Chilean nitrate fields for a salt flat or for a salt-encrusted depression that may represent the basin of a salt lake. Etymol: Spanish, to salt. Pl: salares; salars. See also: playa salband a. A term current among miners for the parts of a vein or dike next to the country rock. b. The selvage of an igneous mass or of a mineral vein. Etymol: German Salband or Sahlband. AGI saleeite 2738

A monoclinic mineral, Mg(UO2 )2 (PO4 )2 .2H2 O ; autunite group; forms pseudotetragonal square yellow plates at Katanga, Zaire. salesite An orthorhombic mineral, Cu(IO3 )(OH); forms blue-green crystals; in Chile. salic Said of certain light-colored silicon- or aluminum-rich minerals present in the norm of igneous rocks; e.g., quartz, feldspar, felspathoid. Also, applied to rocks having one or more of these minerals as major components of the norm. Etymol: a mnemonic term derived from "s"ilicon + "al"uminum + "ic." CF: femic; mafic; felsic. AGI saliferous Salt-bearing; esp. said of strata producing, containing, or impregnated with salt. See also: saline salimeter A hydrometer specially graduated to indicate directly the percentage of a salt (as common salt) in a brine or other salt solution. Webster 3rd salina a. A place where crystalline salt deposits are formed or found, such as a salt flat or pan, a salada, or a salt lick; esp. a salt-encrusted playa or a wet playa. See also: playa b. A body of saline water, such as a salt pond, lake, well, or spring, or a playa lake having a high concentration of salts. AGI c. Saltworks. AGI d. Salt marsh. Etymol: Spanish; saltpit; salt mine; saltworks. Anglicized equivalent: saline. AGI saline a. A natural deposit of halite or of any other soluble salt; e.g., an evaporite. See also: salines b. An anglicized form of salina. In this usage, a saline may refer to various features such as a playa, a salt flat, a saltpan, a salt marsh, a salt lake, a salt pond, a salt well, or a saltworks. AGI c. Salt spring. AGI d. Salty; containing dissolved sodium chloride, e.g., seawater. AGI e. Having a salinity appreciably greater than that of seawater, e.g., a brine. AGI f. Containing dissolved salts at concentrations great enough to allow the precipitation of sodium chloride; hypersaline. AGI g. Said of a taste resembling that of common salt, esp. in describing the properties of a mineral. AGI saline deposit 2739

See: evaporite saline deposits See: salines saline residue See: evaporite salines a. A general term for the naturally occurring soluble salts, such as common salt, sodium carbonate, sodium nitrate, potassium salts, and borax. Syn: saline deposits b. A general term for salt mines, salt springs, salt beds, salt rock, and salt lands. AGI saliniferous Said of a stratum that yields salt. AGI salinity The total amount of solid material in grams contained in 1 kg of water when all the carbonate has been converted to oxide, the bromine and iodine have been replaced by chlorine, and all organic matter has been completely oxidized. Expressed as grams per kilogram of water or parts per thousand. Hy salinity bridge An instrument for determining salinity of water (a salinometer) by measuring electrical conductivity of the water sample with a wheatstone bridge. Hunt salinometer An instrument that measures conductivity of a water sample. This conductivity when compared with that of a sample of known salinity can be converted to an expression of salinity for the unknown. Hy salite A variety of diopside at Sala, Sweden. Also spelled sahlite. salitral

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A term used in Patagonia for a swampy place where salts (esp. potassium nitrate) become encrusted in the dry season. Etymol: Spanish, saltpeter bed. AGI salmiak See: sal ammoniac salmoite See: tarbuttite salmonsite a. A buff hydrous phosphate of manganese and iron, Fe2 O3 .9MnO.4P2 O5 .14H2 O ; orthorhombic; cleavable fibrous masses. An alteration product of hureaulite. From Pala, San Diego County, CA. English b. A mixture of hureaulite plus jahnsite. salnatron Crude soda ash. Standard, 2 salt a. A general term for naturally occurring sodium chloride, NaCl. See also: halite; common salt; rock salt. AGI b. To introduce extra amounts of a valuable mineral into a sample to be assayed or into the working places of a mine, with fraudulent intent. c. The generic term salt is applied to any one of a class of similar compounds formed when the acid hydrogen of an acid is partly or wholly replaced by a metal or a metallic radical. Kaufmann salt-and-pepper sand Sand consisting of a mixture of light- and dark-colored grains. salt anticline A diapiric or piercement structure, like a salt dome except that the salt core is linear rather than equidimensional, e.g., the salt anticlines in the Paradox basin of the central Colorado Plateau. Syn: salt wall. AGI saltation A mode of sediment transport in which the particles are moved progressively forward in a series of short intermittent leaps, hops, or bounces from a bottom surface; e.g., sand particles skipping downwind by impact and rebound along a desert surface, or bounding 2741

downstream under the influence of eddy currents that are not turbulent enough to retain the particles in suspension and thereby return them to the streambed at some distance downstream. It is intermediate in character between suspension and the rolling or sliding of traction. Etymol: Latin saltare, to jump, leap. AGI salt block a. An installation of vacuum pans or grainers for producing salt by evaporation. Kaufmann b. Evaporated salt or fine rock salt mechanically compressed into dense blocks, usually 50 lb (20 to 25 kg) in weight, for stock feeding. Kaufmann salt boot The lower portion of a vacuum pan into which finished salt settles; also, the pit or tank into which the barometric leg of a vacuum pan drops salt. Kaufmann salt bottom A flat piece of relatively low-lying ground encrusted with salt. AGI saltbox A small reservoir or tank, usually cylindrical, with a false bottom for drainage and a cleanout door, placed under an evaporator for removal of salt. Kaufmann salt bridge Usually an inverted glass U-shaped tube filled with a sodium chloride solution, the two legs of which dip into the connecting two vessels of electrolyte, forming an electrochemical cell. Kaufmann salt cake Commercial term for sodium sulfate, Na2 SO4 . AGI salt cote See: saltpit salt-crust process A method of binding mine roadway dust by spraying the area with salt and water. The salt is subjected to wetting and drying cycles. The deposited dust is bound at first by surface tension and then in the recrystallization of the dissolved salt. Nelson 2742

salt dome A diapir or piercement structure with a central, nearly equidimensional salt plug, generally 1 to 2 km or more in diameter, which has risen through the enclosing sediments from a mother salt bed 5 km to more than 10 km beneath the top of the plug. Many salt plugs have a cap rock of less soluble evaporite minerals, esp. anhydrite. The enclosing sediments are commonly turned up and complexly faulted next to a salt plug, and the more permeable beds serve as reservoirs for oil and gas. Certain salt domes are sources of salt and sulfur. Salt domes are characteristic features of the Gulf Coastal Plain in North America and the North German Plain in Europe, but occur in many other regions. CF: salt anticline. See also: salt tectonics. AGI salt effect The solubility of a precipitate in a solution of an electrolyte that has no ion in common with the precipitate is higher than it is in pure water. This is not the salting-out effect. CF: salting out saltern a. A saltworks where salt is produced by boiling or evaporation of salt or brine. AGI b. See: salt garden salt flat The level, salt-encrusted bottom of a lake or pond that is temporarily or permanently dried up; e.g., the Bonneville Salt Flats west of Salt Lake City, UT. See also: playa; alkali flat. AGI salt furnace A simple form of furnace for heating evaporating pans in a salt plant. Kaufmann salt garden A large, shallow basin or pond where seawater is evaporated by solar heat. Syn: saltern salt horse A quarryman's term for aplite. See also: salt vein salting The fraudulent adulteration of a sample, for example, adding a small amount of gold to a sample to make it appear that the gold content of the rock is much higher than it actually 2743

is. Salting may be accidental, caused by the fortuitous segregation of rich mineral during sampling. Sampling methods are conducted to reduce chance segregation to a minimum. Nelson salting a mine Sprinkling gold or rich ore upon or digging it into the ground, or placing it in samples for assay. Drill holes for uranium may be salted before logging with radiation counters. salting evaporator An evaporator that produces crystals or other solids, in distinction to one that only concentrates liquids. Kaufmann salting out a. The addition of sodium chloride or some other electrolyte to a solution of a monelectrolyte to reduce the solubility of the latter. The rarer converse effect is termed salting in. CF: salt effect b. Addition of salt to hasten or to improve the separation of soap from glycerol and weak lye during manufacture. Also, to hasten or to improve the separation of sulfated oil from the residual solution after sulfating. Kaufmann salt mine A mine in which rock-salt deposits are worked. See also: salina. Standard, 2 salt of tartar Potassium carbonate, K2 CO3 . salt of tin A mordant made by dissolving tin in hydrochloric acid. Syn: tin salt; stannous chloride. Standard, 2 saltpan a. A shallow lake of brackish water. b. An undrained natural depression in which water gathers and leaves a deposit of salt on evaporation. CF: playa. Webster 3rd saltpeter a. Potassium nitrate. One of the principal ingredients of black blasting powder. See: niter b. Any earthy nitrate cave deposit. 2744

saltpeter cave A cave in which the earth fill contains appreciable quantities of nitrates; once mined commercially. Syn: saltpeter earth saltpeter earth See: saltpeter cave saltpit a. A pit where salt is obtained. Syn: saltpan b. Reservoir along a salt lake or a seacoast for making solar salt. Kaufmann salt plug The salt core of a salt dome. AGI salt prairie See: soda prairie salts Reaction products of acids (HX) with bases (M.OH). M.OH + HX = MX + H2 O is the simplest formula. Pryor, 3 saltspar Coarsely crystallized and cleavable halite. Spencer, 3 salt stock A general term for a diapiric salt body of whatever shape. AGI salt table The flat upper surface of a salt stock, along which ground-water solution leads to the formation of cap rock by freeing anhydrite (Goldman, 1952). AGI salt tectonics A general term for the study of the structure and mechanism of emplacement of salt domes and other salt-controlled structures. Syn: halokinesis. AGI 2745

salt vein A term applied by quarrymen to a coarse granite vein from 2 in (5 cm) to 2 ft (61 cm) or more thick, intersecting granite or any other crystalline rock. See also: salt horse salt wall See: salt anticline salt well A drilled or dug well from which brine is obtained. See also: brine pit. AGI saltworks Any installation where salt is produced commercially, as by extraction from seawater, from wells, or from the brine of salt springs. Syn: salina; saltern. AGI salvage a. A layer or parting of clay or pug occurring on the wall of a vein. CTD b. To chemically or electrolytically remove diamonds from used diamond bits. Long c. To recover lost bits or drill pipe from a borehole. Long d. To reclaim residual assets left at minesite after the mine has closed. salvage count Number of resettable diamonds salvaged by cutting out of worn or used diamond bit. Long salvage value a. The net worth of diamonds recovered from a used or worn diamond bit or other diamond-inset tool. Long b. The net worth of on-site equipment, and tangible assets after a mine has been closed. Salzgitter ore An important iron ore deposit in Germany. It consists of conglomerated oolitic limonite and contains about 30% iron. Osborne samarium A bright, silvery, lustrous, metallic element of the rare-earth group. Symbol, Sm. It is found along with other members of the rare-earth elements in many minerals, including 2746

monazite and bastnasite, which are commercial sources. Used for carbon-arc lighting for the motion picture industry, for permanent magnets, and in optical masers and lasers. Handbook of Chemistry and Physics, 3 samarium oxide Sm2 O3 has a melting point of 2,350 degrees C. This material has a high thermal neutron cross section, making it usable as a nuclear control rod material. It is also used as a phosphor activator. Lee samarskite A monoclinic mineral, (Y,Ce,U,Fe)3 (Nb,Ta,Ti)5 O16 ; commonly metamict; in granite pegmatites. Syn: ampangabeite; uranotantalite. samite Artificially produced silicon carbide or carborundum. sample a. Representative fraction of body of material; removed by approved methods; guarded against accidental or fraudulent adulteration; and tested or analyzed to determine the nature, composition, percentage of specified constituents, etc., and possibly their reactivity. Bulk samples are large (several tons), so taken as to represent the ore for the purpose of developing a suitable treatment. Channel samples, cores, chips, grab, pannings, stope samples, etc., are small ones-- made primarily to establish the value of the ore reserve. Pryor, 3 b. A section of core or a specific quantity of drill cuttings that represents the whole from which it was removed. CF: borings Long sample cutters In mine valuation and process control, devices that cut a representative fraction from a pile of ore or from a passing stream. Pryor, 3 sample extruder A mechanical device for removing a soil sample from a sampling tube; usually consists of a piston driven by a jackscrew or a hydraulic mechanism. Long sample grinder One who grinds samples of ore to required fineness (depending on character of ore) to prepare them for analysis by assayer. Also called sample crusher. DOT 2747

sampleite An orthorhombic mineral, NaCaCu5 (PO4 )4 Cl.5H2 O ; forms crusts of minute blue crystals. sample log a. Strip of graph paper showing units of depth on which the geologist, using cores and samples, describes the rock formations penetrated by drilling. Wheeler, R.R. b. Syn: drill log c. A log depicting the sequence of lithologic characteristics of the rocks penetrated in drilling a well, compiled by a geologist from microscopic examination of well cuttings and cores. The information is referred to depth of origin and is plotted on a strip log form. See also: well log AGI sample preparation In coal and coke sampling, the process whereby an analysis sample is obtained from a sample by particle size reduction, mixing and sample dividing in successive stages. A stage of sample preparation refers to the sequence of operation leading up to a sample division. BS, 2 sampler a. A mechanical device for selecting a certain fractional part of ore to be used as an assay sample; as, for example, split shovel, riffle sampler, Brunton's mechanical sampler, and Vezin's sampler. Fay b. An instrument designed to take samples of the flame or other explosion gases at predetermined intervals during an explosion. Rice, 2 c. A specific device for recovering samples of overburden. See also: sampler barrel d. One whose duty it is to select and prepare samples of materials and products for an assay or analysis. Fay sampler barrel As used in soil-testing work, one of several tubelike devices used to cut and recover a core sample of soil or soft rock. It can either be a plain tube designed to be driven or pressed into the formation being sampled, or be equipped with cutter heads and helical flutes for taking the sample by rotary methods. Syn: sampler tube sample reduction Reducing a soil, coal, or other sample to manageable size while still obtaining a representative sample. The methods may be divided into manual (for example, quartering) and mechanical; riffle box. Nelson sampler head 2748

An adapter or sub for attaching a sampler to a drill-rod string. Long sampler liner A thin-wall tube fitted inside the barrel of a sampler. The liner serves as a retainer for the sample and when sealed at either end is used as a container in which the sample can be transported safely. Syn: sampler tube sampler tube See: sampler barrel; sampler liner. sample splitter A device for separating dry incoherent material (such as sediment) into truly representative samples of workable size for laboratory study. Syn: riffler sampling a. The gathering of specimens of ore or wall rock for appraisal of an orebody. Since the average of many samples may be used, representative sampling is crucial. The term is usually modified to indicate the mode or locality; e.g., hand sampling, mine sampling, and channel sampling. AGI b. Cutting a representative part of an ore (or coal) deposit, which should truly represent its average value. Most usually a trenchlike cut 4 in (10.2 cm) wide and 2 in (5.1 cm) deep is cut into the clean face of ore (or coal) and across its course. Honest sampling requires good judgment and practical experience. Weed, 2 c. Selecting a certain fractional part of ore or coal from cars, stock piles, etc., for analysis. Fay d. Separation of a representative fraction of ore, pulp, or any product for testing or checking purposes. Pryor, 2 sampling bag Collection devices that use a pump to draw the contaminated air into a contaminant bag. The entire sampling bag containing the contaminated air is sent to the laboratory for analysis. MSHA, 5 sampling instrument A device to determine the methane or dust concentration in mine air to assess safety and health. Instruments are designed to sample instantaneously, or over short periods, or to operate continuously. For methane, warning is required whenever the percentage approaches a danger figure. Dust dangers are not momentary peak concentrations but the bulk quantity of dust breathed over a period. See also: dust sampling; methanometer. The term may also be applied to soil-, coal-, or mineral-sampling devices of an instrumental nature. Nelson 2749

sampling pipe A small pipe built into and through a stopping or seal to enable samples to be taken of the air within the sealed area. The analysis of such samples will give an indication of the state of the fire or heating. In the case of a waste heating a sampling pipe may be pushed into the waste, on the return side, to give an indication of the conditions. Nelson sampling spoon A cylinder with a spoonlike cutting edge for taking soil samples. Long sampling tip The head of a soil auger or soil-sampling barrel. Long sampling train The order of sequence in which personal health sampling equipment parts are assembled together to complete the cycle of assimilated breathed atmosphere that a person is exposed to during the working time period. MSHA, 2 sampling works A plant and its equipment for sampling and determining the value of ores that are bought, sold, or treated metallurgically. samsonite A monoclinic mineral, Ag4 MnSb2 S6 ; steel black but red in transmitted light; at the Samson Mine, Harz, Germany. Samson loader A loader in which the gathering head has rotating arms that pull the stone or coal onto ramps and push it to a scraper chain conveyor, which conveys it to and delivers it at the end of the jib. The jib can be swiveled horizontally and raised or lowered to suit the tub, car, or conveyor to which it is delivering. The whole machine is self-hauling (automobile) on power-driven tractor crawlers with mechanical steering. It is not applicable in steep inclinations. Mason Samson stripper A longwall cutter loader of the plow type, with two cutting blades, one at each end, operated by a hydraulic cylinder, which can give a powerful thrust (about 42 st or 38 t) to the blades and cause them to bite into the coal. While this thrust is being exerted, the 2750

machine is anchored by means of a vertical jack that engages the roof and floor. The jack is built on sliding bars, and the machine is moved by sliding the jack along the bars to the next position for anchoring the machine. It travels alongside the conveyor but is not connected to it. A loading ramp guides the cut coal onto the conveyor. The machine is employed in seams from 4 to 5 ft (1.2 to 1.5 m) thick with a strong roof and floor. Nelson sand a. A rock fragment or detrital particle smaller than a granule and larger than a coarse silt grain, having a diameter in range of 1/16 to 2 mm (62 to 2,000 mu m, or 0.0025 to 0.08 in, or 4 to 1 phi units, or a size between that at the lower limit of visibility of an individual particle with the unaided eye and that of the head of a small wooden match), being somewhat rounded by abrasion in the course of transport. In Great Britain, the range of 0.1 to 1 mm has been used. See also: coarse sand; fine sand. AGI b. A loose aggregate, unlithified mineral or rock particles of sand size; an unconsolidated or moderately consolidated sedimentary deposit consisting essentially of medium-grained clastics. The material is most commonly composed of quartz, and when the term sand is used without qualification, a siliceous composition is implied; but the particles may be of any mineral composition or mixture of rock or mineral fragments, such as coral sand consisting of limestone fragments. Also, a mass of such material, esp. on a beach, desert, or in a streambed. AGI c. Sandstone. AGI d. Separate grains or particles of detrital rock material, easily distinguishable by the unaided eye, but not large enough to be called pebbles; also, a loose mass of such grains, forming an incoherent arenaceous sediment. Building sand, any hard, granular rock material finer than gravel and coarser than dust. The term indicates material comminuted by natural means. Fay e. Detrital material of size range from 2 to 1/16 mm in diameter. Very coarse, 1 to 2 mm; coarse, 1/2 to 1 mm; medium, 1/4 to 1/2 mm; fine, 1/4 to 1/8 mm; very fine, 1/8 to 1/16 mm. AGI f. Granular material, composed mainly of quartz, that will settle readily in water. In the mechanical analysis of soil, sand--according to international classification--has a size between 0.02 mm and 2.0 mm. It has no cohesion when dry or saturated but has apparent cohesion when damp. Nelson g. The residue after amalgamation on plates. Nelson h. In gold-ore treatment, the coarser and heavier portions of the crushed ore in a mill or battery. Nelson i. A driller's term applied loosely to any visibly granular sediment, or to any fluidproductive porous sedimentary unit or objective zone of a well. AGI j. A tract or region of sand, such as a sandy beach along the seashore, or a desert land. AGI k. A sandbank or a sandbar. The term is usually used in the plural; e.g., sea sands. AGI l. A term used in the United States for a rock or mineral particle in the soil, having a diameter in the range of 0.05 to 2 mm; prior to 1947, the range 1 to 2 mm was called fine gravel. The diameter range recognized by the International Society of Soil Science is 0.02 to 2 mm. A textural class of soil material containing 85% or more of sand, with the percentage of silt plus 1.5 times the percentage of clay not exceeding 15; specif. such material containing 25% or more of very coarse sand, coarse sand, and medium sand, and less than 50% of fine sand or very fine sand. The term has also been used for a soil containing 90% or more of sand. AGI 2751

sandarac See: realgar sandbag In the roof of a coal seam, a deposit of glacial debris formed by scour and fill subsequent to coal formation. See also: debris bag sandbag stoppings In many mines a rapid and efficient means of erecting stoppings and walls for the control of ventilation near the face. The walls of doors and air crossings in the workings are often entirely of interlocked sandbags. This method minimizes the use of brattice and gives more permanent results in the workings. Mason sandbar A bar or low ridge of sand that borders the shore and is built to, or nearly to, the water surface by currents in a river or by wave action along the shore of a lake or sea. Syn: sand reef sand bearings The supports of a core in the sand of a mold. Standard, 2 sand bed a. The bed into which molten metal from a blast furnace is run. Standard, 2 b. A floor of a foundry in which large iron castings are made. Standard, 2 sandblasting A method of cleaning metal and stone surfaces with sand sprayed over them through a nozzle at high velocity. Sandblasting is also used to form pits on the intrinsically smooth surfaces of materials, such as glass, requiring a particular finish. Hammond sand bottle A sand-pouring cylinder used for determining the dry density of soil. Nelson sandburrs Concretions of sandstone. See also: burr 2752

sand calcite a. Calcite crystals containing abundant sand grains. b. Siliceous calcite. sand crusher A machine comprising a stationary cylinder into which the sand is charged. Inside this cylinder is fitted a main shaft onto which are bolted retaining discs whose main function is to prevent the loose ball in between each disc from traveling laterally. As the discs rotate on the shaft, the lumpy sand is moved into contact with the balls, which crush the sand to grain size. Osborne sand crystal A large euhedral or subhedral crystal (as of barite, gypsum, and esp. calcite) loaded with detrital-sand inclusions (up to 60%), developed by growth in an incompletely cemented sandstone during cementation. See also: crystal sandstone sand diamonds Name in the trade for diamonds occurring in the gravels and old marine deposits on the Gold Coast of Africa. Griffith sand dike A sedimentary dike consisting of sand that has been squeezed or injected upward into a fissure. See also: neptunian dike sanded in Drill-string equipment, casing, or drivepipe so firmly fastened in a borehole by reason of caving walls or impaction of sand, mud, or drill cuttings that the article cannot be pulled from the borehole. Long Sander's process A flotation process that uses, instead of an acid bath in deep pans, a dilute solution of aluminum sulfate in shallow pans. Liddell sand fill Hydraulic filling, stowing. Use of sand or plant tailings, conveyed underground by water to support cavities left by extraction of ore. Pryor, 3 sand filter 2753

A filter for purifying domestic water, consisting of specially graded layers of aggregate and sand, through which the water flows slowly downwards. A similar type of filter is used for treating sewage effluent, but has coarser sand. Hammond sand flag Fine-grained sandstone that can be readily split into flagstones. AGI sand floor A sand bed in the floor near the blast furnace into which the molten pig is run to be cast into convenient sizes for handling. Mersereau, 2 sand flotation The use of well-graded sand, mixed with water, as the medium for washing coal, as in the Chance washer. See also: dense-medium washer Nelson sandhog See: sand pump sand holder A cavity in a pump barrel to catch sand and keep it out of the way of the plunger or buckets. Standard, 2 sanding-machine worker One who charges mixing mill and removes mixture of sand and refractory clay to be used in packing around ware in bisque firing. DOT sand jack A device consisting essentially of a sandbox and a series of plungers for gradually lowering into position a heavy weight, supported by the plungers, by running out the sand below. Webster 3rd sand leaching Sand leaching or percolation may be practiced wherever the ore is coarse enough to permit free passage of the solvent through the voids. The ore is loaded into large vats or tanks that are then filled with leaching solution. After the solution has been in contact with the ore for a certain time, it is withdrawn, and fresh solution is added. Liquid may 2754

be added from the top (downward percolation) or from the bottom (upward percolation). See also: percolation sandman A laborer who switches flow of sand (waste minerals and water resulting from treatment of ore for removal of valuable minerals) in pipe or flumes from one stope (underground openings from which ore has been mined) to another, so that they will be properly filled with sand (after water has drained off) to support the walls and roof and prevent caving of the ground surrounding the worked out area. DOT sand mold A body of sand and binder surrounding a cavity for the reception of molten metal in the production of castings. The cavity must have dimensional accuracy, and the sand surrounding it must be of sufficient stability to allow the metal to solidify in the exact shape of the impression. The production of the sand mold involves making a pattern of the part to be cast, and packing molding sand round the pattern, which when withdrawn leaves the cavity into which the metal is poured, cores being inserted to leave cavities where desired in the casting. Osborne sand muller A machine for mixing sand and binders by a kneading and squeezing action for use in sand molds. The mixture is usually sand, clay, and water, but synthetic chemical binders may be used. Osborne sand pipe A pipe formed in sedimentary rocks, filled with sand. See also: pipe AGI sand pump a. A pump, usually a centrifugal type, capable of handling sand- and gravel-laden liquids without clogging or wearing unduly. Syn: sandhog; suction bailer. See also: gravel pump; sludge pump; swab. Long b. A pump for lifting tailings at ore-dressing plants. Fay c. A cylinder with a valve at the bottom, lowered into a drill hole from time to time to take out the accumulated slime resulting from the action of the drill on the rock. Also called shell pump; sludger. Fay d. A piston-type bailer. Also called American pump. Long sand-pump dredger

2755

A long pipe reaching down from a vessel into the sand, the latter being raised under the suction of a centrifugal pump and discharged into the vessel itself or an attendant barge. Also called a suction dredger. See also: dredger sand-pump sampler A sand sampler made and used in the same manner as an American pump or sand pump, a. Long sand reef See: sandbar sand-replacement method The normal method of measuring soil density. In its simplest form, the measurement requires only a container full of dry sand of known density, a balance and apparatus for determination of soil moisture content. Nelson sandrock a. A field term for a sandstone that is not firmly cemented. AGI b. A term used in southern England for a sandstone that crumbles between the fingers. AGI c. See: sandstone sand roll A metal roll cast in a mold of sand; distinguished from a chilled roll, which is cast in an iron mold or chill. Standard, 2 sands a. The coarser and heavier portions of the crushed ore in a mill. Fay b. Tailings from the stamp mills of certain copper mines. Fay c. Particles of crushed ore of such a size that they settle readily in water and may be leached by allowing the solution to percolate. CTD sands-and-slimes process Any cyanidation process for gold ores that involves separation of two portions in a classifier, and separate treatment of sands by percolation and slimes by agitation. Nelson sand seam

2756

A quarry term for a more or less minute vein or dike of muscovite (white mica) with some quartz, in cases also with feldspar. sandstone a. A medium-grained clastic sedimentary rock composed of fragments of sand size set in a fine-grained matrix (silt or clay) and more or less firmly united by a cementing material (commonly silica, iron oxide, or calcium carbonate); the consolidated equivalent of sand. The sand particles usually consist of quartz, and the term sandstone, when used without qualification, indicates a rock containing about 85% to 90% quartz. The rock varies in color, may be deposited by water or wind, and contains numerous primary features (sedimentary structures and fossils). Sandstones may be classified according to composition of particles, mineralogic or textural maturity, fluidity index, diastrophism, primary structures, and type of cement. AGI b. A field term for any clastic rock containing individual particles that are visible to the unaided eye or slightly larger. Syn: sandrock AGI sandstone dike a. A clastic dike composed of sandstone or lithified sand; a lithified sand dike. AGI b. Stone intrusion. See also: horseback sandstone grit In geology, a coarse, angular-grained sandstone. sandstone opal A variety of opal occurring in boulders between layers of sandstone and soft clay in the form of pipes in thickness from 1 mm to 3 cm. sandstone pipe See: cylindrical structure sand trap a. A device for separating sand and other heavy or coarse particles from a cuttings-laden; drill-circulation fluid overflowing the collar of a borehole. CF: shaker b. A device, often a simple enlargement, in a conduit for arresting the sand, silt, etc., carried by the water, and generally including means of ejecting them from the conduit. Seelye, 1 sand wall

2757

A temporary independent wall separated from a slag-pocket wall by a thickness of sand for the purpose of easy slag removal and the protection of the permanent wall. AISI sand washer An apparatus for separating sand from earthy substances. Fay sandy See: arenaceous sandy alumina Coarse-grained, porous, granular textured alumina that has not been calcined to the alpha alumina stage (artificial corundum). Resembles fine sand, hence free-flowing, with nondusting qualities. The relatively large surface area of sandy alumina permits its use as an absorbent in dry scrubber units at primary aluminum smelters. sanguinaria a. Sp. Dark green bloodstone variegated by red spots. b. Sp. Hematite. sanidine A monoclinic mineral, (K,Na)AlSi3 O8 ; feldspar group; forms a series with albite; prismatic cleavage; colorless; forms phenocrysts in felsic volcanic rocks. See also: ice spar CF: feldspar; glassy feldspar. sanmartinite A monoclinic mineral (Zn,Fe)WO4 ; resembles wolframite; at San Martin, San Luis Province, Argentina. See also: huebnerite santafeite An orthorhombic mineral, (Na,Ca,Sr)3 (Mn,Fe)2 Mn2 (VO4 )4 (OH,O)5 .2H2 O ; forms black needles on limestone in New Mexico. Santorin earth A pozzolana from the Greek island of Santorin. A quoted composition is 64% SiO2 , 13% Al2 O3 , 5.5% Fe2 O3 , 1% TiO2 , 3.5% CaO, 2% MgO, 6.5% alkalies, and 4% loss on ignition. Dodd sap 2758

The part of the rock in a quarry that is next to the surface or to joints and crevices and has been somewhat stained and softened by weathering. saphir d'eau French water sapphire. An intense-blue variety of the mineral cordierite, occurring in waterworn masses in the river gravels of Ceylon; used as a gem stone. CMD saponification a. The hydrolysis of esters into acids and alcohols by the action of alkalies or acids--by boiling with water or by the action of superheated steam. It is the reverse process to esterification. CTD b. Conversion into soap; the process in which fatty substances form soap, by combination with an alkali. A term used in the flotation process. Fay saponifier Any compound, as a caustic alkali, used in soapmaking to convert the fatty acids into soap. A term used in the flotation process. Standard, 2 saponin Complex polyhydroxy carboxylic flotation reagent used as depressant. It destroys bubble adhesion to collector-coated minerals. Pryor, 3 saponite A monoclinic mineral, (Ca/2,Na)0.3 (Mg,Fe)3 (Si,Al)4 O10 (OH)2 .4H2 O ; smectite group; soft; massive; plastic; unctuous; in veins and cavities in serpentinite and basalt. Syn: bowlingite; mountain soap; piotine; soapstone. Etymol: Greek "sapon" soap. sappare a. See: sapphire b. See: kyanite sapphire a. A blue gem variety of corundum. Syn: sappare b. Any gem-quality corundum other than ruby (fancy sapphire). c. Synthetic alumina single-crystal boules made by the Verneuil process for use as bearings and thread guides. sapphire cat's eye A girasol sapphire with a chatoyant effect. CF: ruby cat's eye 2759

sapphire glass Sapphire-blue glass. sapphire quartz a. An opaque blue variety of quartz colored by nonparallel fibers of silicified crocidolite. Syn: azure quartz; blue quartz. See also: siderite b. Light to pale sapphire-blue quartz in the Western United States. sapphirine a. A rare aluminosilicate of magnesium occurring as disseminated blue chalcedony. Syn: hauynite; blue chalcedony. CMD b. A monoclinic or triclinic mineral, (Mg,Al)8 (Al,Si)6 O20 ; light- to dark-blue to green; in Greenland, Madagascar, and Quebec. saprocol Indurated sapropel. Tomkeieff saprolite A soft, earthy, typically clay-rich, thoroughly decomposed rock, formed in place by chemical weathering of igneous, sedimentary, and metamorphic rocks. It often forms a layer or cover as much as 100 m thick, esp. in humid and tropical or subtropical climates; the color is commonly some shade of red or brown, but it may be white or gray. Saprolite is characterized by preservation of structures that were present in the unweathered rock. Syn: saprolith; sathrolith. CF: geest; laterite. AGI saprolith See: saprolite sapropel a. An aquatic ooze or sludge rich in organic (carbonaceous or bituminous) matter. AGI b. A fluid organic slime originating in swamps as a product of putrification. In its chemical composition, it contains more hydrocarbon than peat. When dry, it is a lusterless, dull, dark, and extremely tough mass that is hard to break up. Stutzer sapropel-clay A sedimentary deposit in which the amount of clay exceeds that of sapropel. AGI sapropelic coal 2760

a. Designation of coal of which the original plant material was more or less transformed by putrefaction. Complete seams of sapropelic coals are rare, but layers or bands of varying thickness within seams are more frequent. This type coal is not abundant and proves troublesome in cleaning processes with jig and dense medium washers because of its lower density relative to humic coals of the same rank and the same ash content. IHCP b. A group of coals, including the cannel and torbanite types, which are largely composed of the indurated jellylike slime derived from macerated organic debris, and known as sapropel, and also of remains of spores and algae. They are typically massive, unbanded coals, which break with a conchoidal fracture and do not show, as a rule, jointing. Tomkeieff c. See: cannel coal saprophyte An organism living on dead or decaying organic material. Rogoff sapropsammite Sapropel rich in sand. Tomkeieff sard A translucent brown variety of chalcedony. Syn: sardius; sardine. See also: carnelian; sardonyx. sardachate A variety of agate with reddish bands of carnelian; carnelian agate. Standard, 2 sardine See: sard sardius See: sard sardonyx a. A variety of chalcedonic quartz. See also: onyx; sard. Fay b. A banded gem variety of chalcedony with straight parallel reddish bands of sard alternating with white or colored bands of another mineral. sargent tube See: acid-etch tube 2761

sarmientite A monoclinic mineral, Fe2 (AsO4 )(SO4 )(OH).5H2 O ; forms minute lemon-yellow crystals in Argentina. sarsen stone See: graywether; druid stone. sartorite A monoclinic mineral. PbAs2 S4 ; metallic; dark gray; conchoidal fracture; in sugary dolomite of the Binnental at Lengenbach, Valais, Switzerland. saryarkite A tetragonal mineral, (Ca,Y,Th)2 Al4 (SiO4 ,PO4 )4 (OH).9H2 O or Ca(Y,Th)Al5 (SiO4 )2 (PO4 )2 (OH)7 .6H2 O . sassoline See: sassolite sassolite A triclinic mineral, H3 BO3 ; forms small pearly scales as an incrustation, or as tabular crystals around fumaroles or vents of sulfurous emanations. Syn: sassoline satelite Fibrous serpentine with a slight chatoyant effect, being pseudomorphous after asbestiform tremolite that has been silicified, in Tulare County, CA. Syn: serpentine cat's-eye satellite imagery The counterpart of an object produced from a satellite by the reflection or rerepresentation of an object produced by optical, electro optical, optical mechanical, or electronic means. ASPRS satellites Certain minerals usually associated with diamond, such as ilmenite, garnet, zircon, rutile, corundum, spinel, olivine, and gorceixite. Chandler 2762

sathrolith See: saprolite satin spar a. A white, translucent, fine fibrous variety of gypsum, characterized by chatoyancy or a silky luster. b. A term used incorrectly for a fine fibrous or silky variety of calcite or aragonite. Syn: atlas spar; feather gypsum; satin stone. satin stone See: satin spar satpaevite A possibly orthorhombic mineral, Al12 V8 O37 .30H2 O ; forms weakly pleochroic yellow flakes in argillaceous anthraxolitic vanadiferous deposits of Kurumsak and Balasanskandyk, Karatau, Kazakhstan. saturated a. A rock or soil is saturated with respect to water if all its interstices are filled with water. AGI b. In petrology, applied to minerals capable of crystallizing from rock magmas in the presence of an excess of silica. Such minerals are said to be saturated with regard to silica and include the feldspars, pyroxenes, amphiboles, micas, tourmaline, fayalite, spessartite, almandine, and accessory minerals, such as sphene, zircon, topaz, apatite, magnetite, and ilmenite. Also applied to igneous rocks composed wholly of saturated minerals. CF: undersaturated c. In fatty acids and other organic compounds, a structure in which each carbon valence is combined either with a distinct atom or by polylinkages. Pryor, 3 d. A term describing a membrane that is filled as completely as practicable with bituminous material. saturated air Air that contains the maximum possible amount of water vapor at that temperature. The amount of water vapor that will saturate a given volume of air increases with the temperature. Therefore, if saturated air is cooled, the excess water vapor condenses in the form of mist. See also: absolute humidity saturated mineral A mineral that can form in the presence of free silica, i.e., one that contains the maximum amount of combined silica. AGI 2763

saturated rock a. A rock having quartz in its norm. AGI b. An igneous rock composed chiefly of saturated minerals. CF: oversaturated rock; undersaturated; unsaturated. AGI saturated surface See: water table saturated unit weight The wet unit weight of a soil mass when saturated. See also: unit weight saturated zone See: zone of saturation saturation curve See: zero air voids curve saturation pressure That pressure for a given temperature at which the vapor and the liquid can exist in stable equilibrium. Strock, 2 sauconite A monoclinic mineral, Na0.3 Zn3 (Si,Al)4 O10 (OH)2 .4H2 O ; smectite group. saukovite A former name for cadmian metacinnabar. sausserite A tough, compact, and white, greenish, or grayish mineral aggregate consisting of a mixture of albite (or oligoclase) and zoisite or epidote, together with variable amounts of calcite, sericite, prehnite, and calcium-aluminum silicates other than those of the epidote group. It is an alteration product of plagioclase; once thought to be a mineral species. saussurite

2764

A tough, compact, white, greenish, or grayish mineral aggregate, resulting from the alteration of feldspars, and consisting of albite, prehnite, zoisite, epidote, and other calcium-aluminum silicates and calcite. Fay; CTD saussuritization The replacement, esp. of plagioclase in basalts and gabbros, by a fine-grained aggregate of zoisite, epidote, albite, calcite, sericite, and zeolites. It is a metamorphic or deuteric process and is frequently accompanied by chloritization of the ferromagnesian minerals. AGI Savelsberg process See: blast roasting saw gang A frame provided with a number of parallel iron bars that are employed to saw stone. See also: stone saw sawsetter In stonework industry, one who maintains stone cutting saws in operating condition, replacing broken and bent saw blades from gang saws. Also called sawmaker. DOT sawtooth back stoping See: overhand stoping sawtooth barrel See: basket sawtooth blasting The blasting of oblique, horizontal holes along a face and so cutting a series of slabs that, in plan, resemble saw teeth. Nelson saw-toothed See: serrate sawtooth floor channeling

2765

A method of channeling inclined beds of marble by removing right-angle blocks in succession from the various beds, thus giving the floor a zigzag or sawtooth appearance. sawtooth stoping In the United States, a form of overhand stoping in which the general line of advance is up the dip. The benches are advanced in a line parallel with the drift. The method permits a large number of machines to be used but requires the miners to work under a comparatively dangerous back. Nelson Sawyear-Kjellgren process A process for converting beryl to beryllium oxide, based on quenching the melted beryl in cold water. The resultant frit reacts with concentrated sulfuric acid, and is steamed and agitated. The liquid, containing soluble beryllium and aluminum sulfates, is filtered and pumped to a tank where ammonium hydroxide is added. The resulting filtrate is further treated with a chelating agent to prevent impurities from precipitating upon subsequent addition of caustic soda. Hydrolysis follows, and the precipitate, beryllium hydroxide, is filtered off. This precipitate is ignited in an electric furnace to form beryllium oxide. USBM, 7 sawyer a. In stonework industry, a general term applied to workers engaged in cutting stone with power driven saws. DOT b. A timber cutter. sax A slate-cutter's knifelike chopping tool for trimming roof slates, having a pointed pick at the back to make nail holes. Also called slate ax. Standard, 2 Saxonian chrysolite A pale wine-yellow topaz. Fay scab a. To trim rough blocks of stone with a pick or broad chisel; used by quarrymen. See also: scabble b. A person who works at a mine contrary to union orders or during a strike. Zern c. A defect consisting of a flat volume of metal jointed to a casting through a small area. It is usually set in a depression, a flat side being separated from the metal of the casting proper by a thin layer of sand. ASM, 1 d. A fault in the base metal for vitreous enameling; the scab is a partially detached piece of metal (which may subsequently have been rolled into the metal surface) and is liable to cause faults in the applied enamel coating. Dodd 2766

scabble To dress (as stone) in any way short of fine tooling or rubbing. CF: scab scabbler In quarry industry, one who roughs stone slabs in blocks with a scabbling pick to produce a uniform rectangular shape and to reduce shipping weight. DOT scabbling The rough trimming of blocks of dimension stone. scabbling hammer A hammer with two pointed ends for picking the stone after the spalling hammer. Fay scabblings Stone chips produced in dressing stone or ore. Arkell scabby In founding, blistered or marred with scabs; said of a casting. Standard, 2 scacchite a. A deliquescent cubic mineral, MnCl2 . Larsen b. A name applied to various minerals, including monticellite, a doubtful selenide of lead, and a brick-red powdery fluoride containing rare earths. scad A name occasionally applied to a nugget, as of gold. Scaife process A modified Ugine-Sejournet process for hot extrusion of steel and other metals. The basic difference between the original Sejournet extrusion process and the Scaife modification is one of direction. In the Sejournet, the billet is forced forward through the die with the mandrel projecting through the die to maintain internal shape. In the modified process, the billet is forced into the closed die and the ram pressure squeezes it back over the mandrel. Both are based on the use of molten glass as a lubricant. Osborne 2767

scalar A quantity fully described by a number, such as a speed that has no associated direction. See also: vector scale a. The ratio between linear distance on a map, chart, globe, model, or photograph and the corresponding distance on the surface being mapped. It may be expressed in the form either of a direct or verbal statement using different units (e.g., 1/24,000 or 1:24,000, indicating that one unit on the map represents 24,000 identical units on the ground) or a graphic measure (such as a bar or line marked off in feet, miles, or kilometers). AGI b. Loose, thin fragments of rock, threatening to break or fall from the roof or wall of a mine. To remove such fragments. c. Crude paraffin wax, obtained by filtering the cooled heavy distillation from petroleum or shale. Standard, 2 d. A fault, in glass or vitreous enamelware, in the form of an embedded particle of metal oxide or carbon. Dodd e. Newc. A small portion of air abstracted from the main current. Also called scale of air, and sometimes spelled skail. f. To regulate the air current in a roadway. BS, 8 g. Used among English miners for carbonaceous shale interbedded with thin layers of coal. Tomkeieff h. The flakes and rubble that fall in after the ore has been removed. Gordon scale cleaner In bituminous coal mining, one who scales off loose pieces of slate from the roof and walls of haulageways, using a pick or a bar. Also called slate handler. DOT scale copper Copper in very thin flakes. Weed, 2 scaled distance A factor relating similar blast effects from various size charges of the same explosive at various distances; it is computed by dividing the distance of concern by an exponential root of the explosive quantity detonated per delay. scale door A door that has an air regulator. Syn: regulator door scalenohedron A closed crystal form, each face of which is a scalene triangle; trigonal scalenohedra have 12 such faces; tetragonal have 8. Adjective: scalenohedral. See: dogtooth spar 2768

scale of hardness See: hardness scale scaler a. An electronic instrument for counting radiation-induced pulses from Geiger counters and other radiation detectors. Lyman b. A laborer who knocks the roasted lead ore off grates with a bar as it is dumped from conveyors into cars below, prior to melting, to separate and recover the lead. Lead ore is loaded on grates attached to a conveyor and carried through a furnace in which the sulfur is driven off by roasting. DOT scales For weighing materials in transit, these include the track scale (carload lots) in which the load is checked by manual operation of weights; platform scales; automatic dump hoppers; conveying weighers that continuously record or register the weight of a portion of passing conveyor belt. Pryor, 3 scale-up In plant design, calculations of required capacities, machine sizes, etc., from data obtained in batch and pilot testing. Pryor, 3 scaling a. The plucking down of loose stones or coal adhering to the solid face after a shot or a round of shots has been fired. Nelson b. Removal of loose rocks from the roof or walls. Also called ramming. CF: exfoliation scaling bar A long metal bar flattened on one end and used to remove loose material from a mine roof or rib. See also: bar scaling furnace A furnace or oven in which plates of iron are heated for the purpose of scaling them, as in the preparation of plates for tinning. Fay scaling of the face In mining, consists of the removal of loose overhanging rock. Streefkerk scall 2769

a. Eng. Loose ground; foliated ground is frequently called scally ground by miners. Also spelled scal. Probably a variation of scale. b. Rock easily broken up because of its scaly structure. scallop a. Eng. To cut or break off the sides of a heading without holing or using powder. b. Eng. To get or hew coal off the face. SMRB c. One of a mosaic of small shallow intersecting hollows formed on the surface of soluble rock by turbulent dissolution. They are steeper on the upstream side, and smaller sizes are formed by faster-flowing water. Syn: flute; solution ripple. AGI scalp a. The process of removing oversize lumps on a continuous basis from a stream of bulk material. b. Removing large pieces of mine waste from run-of-mine coal, usually when passing over a screen, on way to the preparation plant. scalped anticline See: breached anticline scalper Heavy screen shielding fine screen for separating differently sized particles. Bennett scalping a. The removal, by screen or grizzly, of undesirable fine material from broken ore, stone, or gravel. Nelson b. A milling term for the removal of a mineral during closed-circuit grinding of the ore. Pryor, 2 scalping screen A coarse primary screen or grizzly; usually a vibrating grizzly. Nichols, 1 scaly Said of the texture of a mineral, esp. a mica, in which small plates break or flake off from the surface like scales. AGI scamy Eng. Applied to freestone in thin layers, mixed with mica. 2770

scamy post N. of Eng. Soft, short, jointy freestone, thinly laminated and much mixed with mica. scandium A silvery-white metallic element that develops a slightly yellowish or pinkish cast upon exposure to air. Symbol, Sc. It occurs as a principal component in the rare mineral thortveitite; or is extracted as a by-product from uranium mill tailings. It is of interest for use in space missiles. Handbook of Chemistry and Physics, 3 scanning electroprobe X-ray microanalyzer An instrument for metallurgical research. It can create visual images of the minutest particles in metals and alloys by use of X-ray beams. Magnification is up to 3,000 times, and particles smaller than a millionth of an inch can be examined in detail. Nelson scantite A gage by which slates are assorted in sizes. scantling a. The dimensions of a stone in length, breadth, and thickness. Standard, 2 b. Stones more than 6 ft (2 m) long. CTD c. A piece of timber of thickness from 2 to 4 in (5 to 10 cm) and of width from 2 to 4-1/2 in (5 to 11 cm). CTD d. Small timber, such as 2 in by 3 in (5.1 cm by 7.6 cm), 2 in by 4 in (5.1 cm by 10.2 cm), etc., used for studding. Crispin scapolite a. A mineral group, Na4 Al3 Si9 O24 Cl (marialite), to Ca4 Al6 Si6 O24 (CO3 ,SO4 ) (meionite); a tetragonal isomorphous series; occurs in calcium-rich metamorphic rocks or igneous rocks as the product of alteration of plagioclase feldspar. b. Any mineral of the scapolite group, intermediate in composition between marialite and meionite (Ma:Me from 2:1 to 1:3), containing 46% to 54% silica, and resembling feldspar when massive, but having a higher density and a fibrous appearance. Intermediate compositions were formerly called dipyre and mizzonite for Ma- and Me-rich samples, respectively. Syn: wernerite scapolitization Introduction of, or replacement by, scapolite. Plagioclase is commonly so replaced. The replacement may involve introduction of chlorine. AGI scar 2771

In founding, an imperfect spot in a casting. Standard, 2 scarbroite A hexagonal mineral, Al5 (OH)13 (CO3 ).5H2 O ; compact; fine-grained; in vertical fissures in sandstone at South Bay, Scarborough; in sandstone at Yorkshire, England. Also spelled scarbroeite. Syn: tucanite scarcement A projecting ledge of rock, left in a shaft as footing for a ladder or to support pitwork. Fay scares a. Lenticular pockets of clean coal in sandstone, usually found in the region of a washout. Also called coal scares. Tomkeieff b. N. of Eng. Thin laminae of pyrite in coal. scarf a. A lapped joint made by beveling, notching, or otherwise cutting away the sides of two timbers at the ends, and bolting or strapping them together so as to form one continuous piece, usually without increased thickness. Also called scarf joint. Standard, 2 b. A piece of metal shaped or beveled for a scarf weld. Standard, 2 scarfer In the iron and steel industry, one who tends rolls through which skelp (steel strips for making pipe or tube) or steel sheet is run to bevel edges prior to its being formed into tube. DOT scarfing a. Splicing timbers, so cut that when joined the resulting piece is not thicker at the joint than elsewhere. Fay b. Tapering the ends of two pieces to be joined to avoid an enlarged joint. Crispin c. Cutting surface areas of metal objects, ordinarily by using a gas torch. The operation permits surface defects to be cut from ingots, billets, or the edges of plate that is to be beveled for butt welding. ASM, 1 scarf joint a. A butt joint in which the plane of the joint is inclined with respect to the main axis of the members. ASM, 1 b. See: scarf scarifier 2772

A machine with downward projecting teeth for breaking hard soil at quarries and opencast pits. It may be self-propelled or attached to another vehicle. See also: rooter scarify To roughen up, as a road, for repairs. Crispin scarp a. A line of cliffs produced by faulting or by erosion. The term is an abbreviated form of escarpment, and the two terms commonly have the same meaning, although scarp is more often applied to cliffs formed by faulting. See also: fault scarp b. A relatively straight, clifflike face or slope of considerable linear extent, breaking the general continuity of the land by separating surfaces lying at different levels, as along the margin of a plateau or mesa. A scarp may be of any height. The term should not be used for a slope of highly irregular outline. CF: cuesta scarring The formation of scars or scaurs in roasting pyrite for sulfuric acid manufacture. Fay scatter Deviation of portions of a radiation beam by scattering centers in the medium through which the beam passes. In ultrasonics, it occurs by reflection, refraction, or diffraction at any acoustical discontinuity comparable in size with, or larger than, the wave length used; in radiography, the scatter occurs by the Compton, photoelectric, and pairproduction processes. ASM, 1 scatter pile In underground mining, ore left adjacent to a longwall face to stop flying ore from being lost when blasting. A secondary use is to confine ventilation. Pryor, 3 scavenge To pick up surplus fluid and return it to a circulating system. Nichols, 1 scavenger a. Any chemical that is added to a system or a mixture to consume, or to convert to an inactive form, small quantities of impurities or undesired materials. CCD, 2 b. In flotation, a rougher cell in which the tailings, before being rejected as waste, are subjected to a scavenging flotation treatment. Concentrating tables are also used as scavenger machines. Hess c. In metallurgical operations, an active metal added to 2773

combine with oxygen and/or nitrogen in the molten metal and so cause removal of impurities into slag. CCD, 2 d. Oxygen, iodine, or more complex materials that, when added to a mixture, combine with free radicals in the mixture and permit the measurement of these radicals. CCD, 2 scavenger cells Secondary cells for the retreatment of tailings. BS, 5 scavenger mining The removal of coal so close to the surface as to undermine the topsoil, resulting in devastation above ground. Usually engaged in by an independent operator working an old mine on a lease from a major corporation. Korson scavenging In mineral processing, final stage in flotation of mineralized froth before discard of tailing. The cells are so worked as to remove for retreatment as much low-grade rising mineral as possible under the given working conditions. Pryor, 3 scawtite A monoclinic mineral, Ca7 Si6 (CO3 )O18 .2H2 O ; forms bundles of thin, colorless, tabular crystals at Scawt Hill, County Antrim, Ireland. scepter quartz Quartz crystals resembling a scepter in shape. schafarzikite A tetragonal mineral, FeSb2 O4 ; red to reddish-brown. schairerite A trigonal mineral, Na21 (SO4 )7 F6 Cl ; colorless; at Searles Lake, CA. CF: galeite schallerite A trigonal mineral, (Mn,Fe)16 Si12 As3 O36 (OH)17 ; dimorphous with nelenite; reddishbrown. schapbachite 2774

An isometric mineral, AgBiS2 ; a high-temperature polymorph of matildite and member of the halite group; not recognized as a valid mineral species; occurs as acicular crystals, granular, or massive. See also: matildite schaum earth Same as aphrite. scheelite A tetragonal mineral, CaWO4 , with molybdenum replacing tungsten toward powellite CaMoO4 ; prismatic cleavage; sp gr, 5.9 to 6.1; varicolored, fluoresces bright blue; in limestone and pneumatolitic veins near granite contacts, granite pegmatites; a source of tungsten. scheererite A whitish, gray; yellow, green, or pale reddish; brittle; tasteless; inodorous hydrocarbon; melts at 44 degrees C; soluble in alcohol and ether; may be distilled without decomposition, boiling at 92 degrees C. Syn: xylocryptite schefferite A mineral, (Na,Ca)(Fe,Mn)Si2 O6 ; brown to black; a variety of manganoan aegirine. scheibeite a. Fossil resin found in brown coal. Tomkeieff b. A former name for phoenicochroite. schematic Showing principles of construction or operation, without accurate mechanical representation. Nichols, 1 scheteligite a. A very rare, weakly radioactive, orthorhombic(?), black mineral, (Ca,Y,Sb,Mn)2 (Ti,Ta,Nb,W)2 O6 (O,OH) , found at Torvelona, Norway, in pegmatite with plagioclase, tourmaline, bismuth, euxenite, thortveitite, monazite, alvite, beryl, garnet, and magnetite. Small amounts of uranium may be present. Crosby b. A name for an incompletely described possible member of the betafite subgroup of the pyrochlore group. Schicht mixed-flow fan

2775

In this fan, the blades are mounted on the curved portion of a dish-shaped rotor and are designed to impart dynamic energy but no pressure or static energy to the air, the dynamic energy being converted to pressure in the diffuser. The fan is suitable for water gauges up to 20 in (50.8 cm) and there is an absence of noise. It is useful where the resistance of the mine is known and not liable to alter materially. Sinclair, 1 schiefer spar A variety of calcite occurring in very thin plates or scales. Fay schiller A phenomenon related to sheen; an almost metallic iridescent shimmer or play of color seen just below the surface in certain varieties of pyroxene, feldspar, etc. Etymol: German. See also: adularescence; schillerization. schiller-fels Enstatite or bronzite peridotite with poikilitic pyroxenes. Orthorhombic pyroxenes possess the poikilitic texture to a peculiar degree, and esp. when more or less altered to bastite, the term schiller is esp. applied to them. Fay schillerization The development of poikilitic texture by the formation of inclusions and cavities along particular crystal planes, largely by solution somewhat as are etch figures. Fay schiller obsidian Obsidian with schiller effect. schiller spar An altered enstatite or bronzite, having approx. the composition of serpentine. Syn: bastite schist A strongly foliated crystalline rock, formed by dynamic metamorphism, that can be readily split into thin flakes or slabs due to the well developed parallelism of more than 50% of the minerals present, particularly those of lamellar or elongate prismatic habit, e.g., mica and hornblende. The mineral composition is not an essential factor in its definition unless specif. included in the rock name, e.g., quartz-muscovite schist. Varieties may also be based on general composition, e.g., calc-silicate schist, amphibole 2776

schist; or on texture, e.g., spotted schist. See also: magnesian schist; pelitic schist. CF: paraschist AGI schistose Said of a rock displaying schistosity. AGI schistosity The foliation in schist or other coarse-grained, crystalline rock due to the parallel, planar arrangement of mineral grains of the platy, prismatic, or ellipsoidal types, usually mica. It is considered by some to be a type of cleavage. Adj: schistose. AGI schizolite A light-red variety of manganoan pectolite. See: pectolite schlieren a. Tabular bodies, generally a few inches to tens of feet long, that occur in plutonic rocks. They have the same general mineralogy as the rocks, but because of differences in mineral ratios, they are darker or lighter; the boundaries with the plutonic rock tend to be transitional. Some schlieren are modified inclusions, others may be segregations of minerals. Etymol: German. Sing: schliere. Also spelled schliere. Adj: schlieric. CF: flow layer b. Regions of different density in fluid, esp. as shown by special apparatus. Hunt c. A method or apparatus for visualizing or photographing regions of varying density in a field of flow. Hunt Schmidt apparatus Apparatus used to determine the position of rest of a freely swinging shaft plumbline. BS, 7 Schmidt-type magnetic field balance This has been the most commonly used magnetic instrument for prospecting on land. It consists of a magnet pivoted near but not at its center of mass, so that the magnetic field of the earth creates a torque around the pivot that is opposed by the torque of the gravitational pull upon the center. The angle at which equilibrium is reached depends on the strength of the field. Readings are taken through an eyepiece by comparing a scale reflected from a mirror on the magnetic element with a fixed scale. The balance may be either the horizontal or vertical type. Dobrin schmiederite 2777

A monoclinic mineral, Cu2 Pb2 (SeO3 )(SeO4 )(OH)4 ; light blue; at La Rioja, Argentina. Also spelled schmeiderite. Schneider furnace A distillation furnace for the reduction of zinc ores containing lead, with a recovery of the latter metal as well as the zinc. Fay schoderite A monoclinic mineral, Al2 (PO4 )(VO4 ).8H2 O ; yellow-orange. schoenfliesite The mineral group burtite, natanite, schoenfliesite, vismirnovite, and wickmanite. schoepite An orthorhombic mineral, UO3 .2H2 O ; strongly radioactive; perfect cleavage; yellow; an alteration product of uraninite or ianthinite. Formerly called schoepite I. Syn: epiianthinite See also: metaschoepite; paraschoepite. Scholl's method A method for determining the uranium in any of its ores in which the uranium is extracted with dilute nitric acid. This extract is then diluted, filtered, and treated with ferric chloride and sodium carbonate causing the vanadium iron and aluminum to precipitate. The uranium is then precipitated from the filtrate by boiling with caustic soda and purified by solution in nitric acid. Following precipitating with ammonia, the ammonium uranate is ignited to the oxide, and weighed. When this weight is multiplied by the factor 0.847, it gives the weight of uranium. scholzite An orthorhombic mineral, CaZn2 (PO4 )2 .2H2 O; dimorphous with parascholzite; colorless to white. Schone's apparatus An elutriator consisting of a tall glass vessel tapering toward the bottom, where water enters at a constant rate. Schone's formula is: V = 104.7 (S1)1.57 D1.57 where V is the velocity of water (millimeter/second) required to carry away particles of diameter D and specific gravity, S. (Dodd, 1964) schorlite 2778

a. A black variety of tourmaline. Dana, 4 b. A discontinued term for schorl. schorlomite An isometric mineral, Ca3 Ti2 (Fe2 Si)O12 , with Ti decreasing toward andradite in the garnet group. schorl rock A term used in Cornwall, England, for a granular rock composed essentially of aggregates of needlelike crystals of black tourmaline (schorl) associated with quartz, and resulting from the complete tourmalinization of granite. AGI Schottky defect a. An atomic vacancy. Van Vlack b. A point defect in a crystal structure where an atom is missing from a correct site. Syn: vacancy c. A defect in anionic crystal in which a single ion is removed from its interior lattice site and relocated in a lattice site at the surface of the crystal. d. A defect in anionic crystal consisting of the smallest number of positiveion vacancies and negative-ion vacancies that leave the crystal electrically neutral. Schramhobel cutter plow See: cutter plow schreibersite A tetragonal mineral, (Fe,Ni)3 P ; highly magnetic; contains small amounts of cobalt and traces of copper and tarnishes to brass yellow or brown. Schreibersite occurs in tables or plates as oriented inclusions in iron meteorites. Syn: rhabdite schroeckingerite A triclinic mineral, NaCa3 (UO2 )(CO3 )3 (SO4 )F.10H2 O; radioactive; soft; greenishyellow color and fluorescence; an alteration product of uraninite; a source of uranium. Also spelled schroeckingerite. Syn: dakeite schrotterite An opaline variety of allophane rich in aluminum. Material at the type locality is a mixture of glassy hyalophane and earthy variscite. schuchardtite A name for interlayered Ni-rich vermiculites and chlorites. 2779

schuetteite A hexagonal mineral, Hg3 (SO4 )O2 ; yellow. schuilingite An orthorhombic mineral, PbCu(Nd,Gd,Sm,Y)(CO3 )3 (OH).1.5H2 O ; light blue. schultenite A monoclinic mineral, PbHAsO4 ; forms colorless thin crystalline plates; resembles selenite; at Tsumeb, Namibia. Schulze elutriator The original type of water elutriator; it has since been improved. Dodd Schulze-Hardy rule This states that the ion that causes a soluble to coagulate is opposite in sign to the electric charge of the colloidal particle; further, the coagulating power increases with the valency of the ion. Pryor, 3 Schulz's theory A mine subsidence theory that distinguishes between the manner of fracture of shale and sandstone, holding that the former rock breaks along vertical lines irrespective of the angle of dip, and that the latter has a vertical fracture over a rise face and a fracture at right angles to the bed over a dip face. The theory predicts vertical lines of break in either rock for a level seam, and is, indeed, a compromise between the vertical theory and that of the normal. Briggs Schumann plot Integral plot in graphic representation of sizing analysis. Pryor, 3 schungite See: shungite schwatzite A mercurian variety of tetrahedrite. Also spelled schwazite. scientific alexandrite 2780

A synthetic corundum colored by vanadium oxide to resemble true alexandrite in some of its optical characters. scientific emerald A synthetic beryl glass colored by chromic oxide to resemble true emerald in color. scintillascope See: scintillation counter scintillation A very small light flash excited in certain natural or synthetic crystals by radioactive rays or particles; the basic phenomenon of the scintillation counter in which the photoelectric effect of the scintillation flashes is amplified and measured to give a measure of intensity of radioactivity. AGI scintillation counter A sensitive instrument for the location of radioactive ore, such as uranium, radium, and thorium. It uses a transparent crystal that gives off a minute flash of light when struck by a gamma ray, and a photomultiplier tube that produces an electrical impulse when the light from the crystal strikes it. The scintillation counter has advantages over the Geiger counter as it is more sensitive, more compact, and can distinguish between types of radiation. The instrument responds to gamma rays emitted from the minerals mentioned and charts their intensity. It is used in aerial geophysical prospecting and the resulting maps are used as a guide for a more detailed ground investigation. See also: coal-sensing probe Nelson scintillation probe An electronic logging device consisting of a scintillation-type gamma-ray detecting unit built into a container small enough to be lowered into a borehole. Long scintillometer An instrument for measuring radioactivity, based on emission of light by certain crystals under impact of gamma rays. AGI scissor fault A fault of dislocation, in which two beds are thrown so as to cross each other. CF: hinge fault; rotational fault. Zern 2781

sclaffery Scot. Liable to break off in thin fragments, as the roof of a mine working. sclerometer An instrument for determining the degree of hardness of a mineral by ascertaining the pressure on a moving diamond point necessary to effect a scratch. Standard, 2 scleroscope hardness test A test to determine the hardness of metals by measuring the rebound from them of a standard diamond-tipped hammer dropped from a given height. See also: Shore hardness test; Shore scleroscope. Nelson sclerotinite A maceral of coal within the inertinite group, consisting of the sclerotia of fungi or of fungal spores characterized by a round or oval form and varying size. AGI scobs The dross of metals. Standard, 2 scolecite A monoclinic mineral, CaAl2 Si3 O10 .3H2 O ; zeolite group; pseudotetragonal; fibrous to acicular; can show wormlike motion if heated; in cavities in basalt and hydrothermal veins. sconce A protecting cover or screen; protection; shelter. A metal cover and holder combined for holding a miner's candle, esp. for hanging on wooden timbers. Webster 3rd; Fay scone High-grade tin requiring little or no dressing. Nelson scones Firebricks of a certain standard size. Osborne scoop 2782

a. Diesel- or battery-powered equipment with a scoop attachment for cleaning up loose material, for loading mine cars or trucks, and hauling supplies. b. A large-sized shovel with a scoopshaped blade. Zern c. Coal miner's shovel; also sometimes used to refer to scraper. BCI d. See: scraper bucket e. A device that gathers ore at feed end of ball mill and delivers it into the feed trunnion. Pryor, 3 scoopman In bituminous coal mining, a laborer who places the cable-drawn scoop of a scraper loader in position for it to scrape up coal (blasted from the working face) as it is dragged by the hoisting engine to a point where the coal is dumped into mine cars. DOT scooptram Similar to a front end loader; a low-profile loader articulating in the center with a large bucket in front (usually five tons or more) that transports ore in an underground mine. The operator sits at sideway controls facing the loader and drives it in either direction as required. Usually used for loading ore cars, shuttle cars, or hauling directly to an ore pocket. scopulite A rodlike or stemlike crystallite that terminates in brushes or plumes. AGI score a. A bill run up by a collier in bad times for the necessaries of life. Fay b. See: task c. To mark with scratches or furrows; e.g., rocks in certain localities were scored by glacial drift. Standard, 2 scoria a. A bomb-size pyroclast that is irregular in form and generally very vesicular. In less restricted usage, a vesicular cindery crust on the surface of andesitic or basaltic lava, the vesicular nature of which is due to the escape of volcanic gases before solidification; it is usually heavier, darker, and more crystalline than pumice. The adj. form, scoriaceous, is usually applied to pyroclastic ejecta. Cinder is sometimes used synonymously. CF: pumice b. A local term for melted or partly melted rock surrounding burned-out coal beds in the Western United States. See also: clinker scoriaceous Said of the texture of a coarsely vesicular pyroclastic rock (e.g., scoria), usually of andesitic or basaltic composition, and coarser than a pumiceous rock. The walls of the 2783

vesicles may be either smooth or jagged. Also, said of a rock exhibiting such texture. Syn: scoriform; scorious. CF: vesicular scorification The separation of gold or silver by heating it to a high temperature with a large amount of granulated lead and a little borax, in a scorifier. The gold or silver dissolves in the molten lead, which sinks to the bottom of the vessel, while the impurities form a slag with the lead oxide that is produced. Nelson scorifier A bone ash or fireclay crucible somewhat larger than a cupel; used in assaying and in the metallurgical treatment of precious metals. Nelson scoriform See: scoriaceous scorious See: scoriaceous scorodite An orthorhombic mineral, FeAsO4 .2H2 O ; variscite group; colorless or pale-green to brown; in gossans, oxidized zones of metal veins, and around hot springs; a minor source of arsenic. Scortecci process A process for direct reduction of iron pyrites that depends on the dissociation of pyrites in the absence of air, and in the presence of carbon, with the formation of iron and carbon disulfide. Osborne scorzalite A monoclinic mineral, (Fe,Mg)Al2 (PO4 )2 (OH)2; lazulite group; forms a series with lazulite; light blue. scotch a. A wooden stop-block or iron catch placed across or between the rails of underground roadways, to keep the cars from running loose, or to hold them when standing upon an 2784

inclined plane. b. Leic. The lower lift of coal that is wedged up in driving a heading. c. To dress, as stone, with a pick or picking tool. Standard, 2 scotch block a. A wedge or block temporarily fitted to a running rail in order to hold (scotch) the wheel of a railway vehicle. Hammond b. One form of gas port in an open-hearth steel furnace; the distinguishing feature is that it is monolithic, being made by ramming suitably graded refractory material around a metal template. Dodd scotching A method of dressing stones either with a pick or with pick-shaped chisels. Fay Scotch pebble A rounded fragment of agate, carnelian, cairngorm, or other variety of quartz; found in gravels of parts of Scotland and used as a semiprecious stone. Scotch pig A very pure grade of pig iron. Standard, 2 Scotch topaz Applied in the gem stone trade to yellow transparent quartzes resembling Brazilian topaz in color; used for ornamental purposes. See also: citrine scour The erosion of the bed or bank of a river or of a seacoast by the action of flowing water and waves. See also: scour protection scour and fill A process of alternate excavation and refilling of a channel, as by a stream or the tides; esp. such a process occurring in time of flood when the discharge and velocity of an aggrading stream are suddenly increased, causing the digging of new channels that become filled with sediment when the flood subsides. Syn: washout scouring cinder A basic slag that attacks the lining of a shaft furnace. Fay scour protection 2785

The protection of soil or other submerged material against scour, by the use of steel sheet pilings, revetment, riprap, or brushwood, or by combining any such methods as most suited to the site. See also: lining Hammond scout a. One who gathers information about the drilling rig of a rival company for the benefit of its employer. Also called snooper. Long b. An engineer who makes a preliminary examination of promising oil and mining claims and prospects. Long c. One who goes into a potential area, esp. for oil or gas, to lease or option the land. Long scout boring Trial bores made to test formations of area being prospected. Pryor, 3 scouter In stoneworking, a quarryman whose function is to split off large portions of rock by means of a jump drill and wedges. Standard, 2 scout hole A borehole penetrating only the uppermost part of an orebody with the intention of delineating its surface configuration. Also, a shallow hole drilled to scout for an indication of ore or to explore an area in a preliminary manner. Long scout prospecting Prospecting undertaken in new country in which the first step is to scout prospect rivers, streams, and creeks by washing gravel obtained from their beds. Griffith scovan Corn. A tin-bearing lode. scovillite A former name for rhabdophane. scow A device used to a limited extent to load solid blocks of coal. The scow proper is a flat steel plate that is moved underneath the undercut and blocks the coal by means of a hoist and a tail rope. The coal is then wedged down on the scow, and the solid block is hauled 2786

by means of the hoist and a headrope to a delivery point where it is transferred to cars. Jones, 1 scowl bowl See: scowle scowle Forest of Dean. Ancient ironstone quarry and mine workings. Syn: scowl bowl scrablag Hardpan; Isle of Man, U.K. scram a. To search for and extract ore in a mine that is apparently worked out. Weed, 2 b. An Alabama term for a small soft-coal mine complete in itself. scram drift See: scram drive scram drive a. Underground drive above the tramming level, along which ore is moved by scrapers (slushers) to a discharge chute. Pryor, 3 b. See: scram drift scrap a. Defective product not suitable for sale. ASM, 1 b. Discarded metallic material, from whatever source, which may be reclaimed through melting and refining. ASM, 1 c. Som. Stone only fit for rough walling. Arkell d. See: diamond scrap scrap baler In the iron and steel industry, one who presses, in a baling press, steel scrap into compact blocks, for remelting in the open-hearth furnace. Also called scrap builder; scrap pressman. DOT scrap bar The uneven ends of the muck bars. Mersereau, 2 2787

scrap-carbon process Indian scrap-carbon process using 100% steel scrap in which petroleum coke replaces carbon and acid slag replaces silicon. The hearth is protected from erosion by spreading an easily fusible silica sand over the banks before charging, and manganese ore is used instead of iron ore for oxidizing the carbon. Osborne scraper a. A rod for cleaning out a shothole prior to charging with explosives. See also: stemmer; spoon. Nelson b. A mechanical contrivance used at collieries to scrape the culm or slack along a trough to the place of deposit. c. A machine used in mines for loading cars and transporting ore or waste for short distances. There are two basic types of scraper: (1) the hoe or open type, which is particularly suitable for moving coarse, lumpy ore; and (2) the box or closed type, which is particularly suited for handling fine material, esp. on a loading slide. Syn: box scraper d. A digging, hauling, and grading machine having a cutting edge, a carrying bowl, a movable front wall (apron), and a dumping or ejecting mechanism. Also called carrying scraper or pan. Nichols, 1 e. An apparatus used to take up coal from the floor of a mine, after it has been shot, and deposit it either in cars or in a conveyor. See: spoon f. A rubber-tired device used to move earth in surface mining. BCI g. See: carryall h. See: poker man i. The name applied to a bowl scraper or a multibucket excavator. Also known as a scraper excavator. Hammond scraper and break detector In Great Britain, every shot firer is provided with a scraper for cleaning out shotholes, and in safety lamp mines a break detector must also be provided. The two tools are combined in the scraper and break detector. It can clean out a shothole and detect breaks in the walls of 1/8 in (3 mm) or more in width. The firing of a shot in a hole traversed by a crack exceeding 1/8 in in width is forbidden. Nelson scraper box plow a. A layout of rope-drawn scraper boxes with knives on the face side. They are drawn to and fro, and pushed against the face by guides controlled by rams. A haulage of 250 hp (186 kW) must be installed in a semipermanent engineroom; it has a rope diameter of 11/4 in (3 cm) and a speed of 3 ft/s (1 m/s). No conveyor is required as the coal is scraped by boxes to the loading point. The maximum workable seam thickness is 20 in (51 cm) on gradients of 0 degrees to 30 degrees ; maximum length of face, 220 to 275 yd (200 to 250 m); and advance per shift, 6-1/2 to 8 ft (2.0 to 2.4 m). Nelson b. See: Haarmann plow; Kema plow; Gusto scraper box. scraper bucket

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a. One of the excavating bowls or buckets that form part of a scraper. Hammond b. In coal mines, the scraper bucket is a bottomless, three-sided box, with a hinged back. The hinge operates in a forward direction so that on the return journey on the coal face the back opens allowing the box to remain empty. On the loading journey, the coal closes the hinge and the material is drawn or scraped forward to the point of discharge. Syn: scoop scraper chain conveyor See: chain conveyor scraper conveyor a. A mechanical device for conveying coal, rock, ashes, culm, etc., in a metal trough by means of scrapers attached to a rope or chain. b. A conveyor consisting of chain-drawn scrapers or flights running in a trough through which they push the material to be transported. Also called drag-link conveyor; flight conveyor; chain conveyor. BS, 5 scraper hoist A power-driven hoist that operates a scraper to move material (rock or coal) to a loading point. scraper loader a. A machine used for loading coal or rock by pulling an open-bottomed scoop back and forth between the face and the loading point by means of ropes, sheaves, and a multiple drum hoist. The filled scoop is pulled on the bottom to an apron or ramp where the load is discharged onto a car or conveyor. Jones, 1 b. A combined scraper and transporting machine. Originally towed by a tractor, but now diesel-electric with a direct current motor in each wheel. Pryor, 3 c. A double-drum winch with two steel ropes. The loading capacity of a scraper loader ranges from 30 to 80 tons per hour depending on conditions. The loader is used for transporting and loading coal on longwall faces, for removing and loading stone in tunnels, and for stowing dirt on longwall faces. Syn: slusher scraper plow One scraper box with picks, rope-drawn and unguided along the face. A 30-hp (22.4kW) haulage advances with the face, which is made convex to eliminate the need for guides. Speed, 3 to 4 ft/s (approx. 1 m/s). Suitable seam conditions; thickness, 12 to 24 in (30 to 60 cm) at gradients of 0 degrees to 35 degrees (preferably 15 degrees to 25 degrees ); and maximum length of face, 65 yd (60 m). Syn: porte et gardin plow Nelson scraper ripper 2789

Strip-mine equipment that breaks, loads, and hauls coal. Features include ripping teeth on the lip for breaking the coal and a flight conveyor for carrying the broken coal away from the lip. As the ripper teeth bite into and loosen the coal, the conveyor sweeps the loose coal upward and prevents buildup ahead of the lip. Coal Age, 3 scrap forgings Forgings formed from wrought-iron scrap. Standard, 2 scrap hoist operator In the iron and steel industry, one who operates a skip hoist to carry scrap material to the furnaces. DOT scrap mica Mica that because of size, color, or quality is below specifications for sheet mica. Includes flake mica and the mica, except sheet, obtained from pegmatite mining as a sole product or as a byproduct, from the preparation of sheet mica, and from waste in fabricating sheet mica. Skow scrap picker A person employed on the slag dump to pick out pieces of iron carried to the dump in slag ladles. Fay scrapping bottom coal Lifting coal that has been left by an undercutting machine. Zern scrap sorter In metallurgy, a laborer who sorts scrap metal and removes foreign matter preparatory to use in recasting. DOT scratch A calcareous, earthy, or strong substance that separates from seawater in boiling it for salt. See: striation scratch pan A pan in saltworks to receive the scratch. Fay screaming joint 2790

A joint from which air leaks and makes a screaming noise. Compressed air escaping at a screaming joint or hole in an air hose can be the cause of a mine fire. Sinclair, 1 scree A sieve, screen, or strainer; a coal screen. See also: talus scree bars Scot. Bars of which a scree is constructed. See also: scree screen a. A large sieve for grading or sizing coal, ore, rock, or aggregate. It consists of a suitably mounted surface of woven wire or of punched plate; it may be flat or cylindrical, horizontal or inclined, stationary, shaking, or vibratory, and either wet or dry operation. See also: Bradford breaker; shaking screen; stationary bar screen; vibratory screen. Nelson b. A cloth brattice or curtain hung across a road in a mine to direct the ventilation. See also: brattice c. A perforated sheet placed in the gating system of a mold to separate dirt from molten metal. ASM, 1 screen analysis a. The size distribution of noncohering particles as determined by screening through a series of standard screens. Harbison-Walker b. See: sieve analysis c. The percentage of a sample retained on each size of a series of standard laboratory screens. Nelson d. Determination of the particle-size distribution of a soil, sediment, or ore by measuring the percentage of the particles that will pass through standard screens of various sizes. Syn: grading test screen box A container in which diamond screens are inserted and in which the material (diamond particles) that passes through a sieve or screen collects and is retained. Long screen chute A discharge chute equipped with a screen section, either stationary or vibrating, to remove the finer portions of the material being handled from the major line of flow. screen cloth A woven medium suitable for use in a screen deck. BS, 5 screen deck 2791

A surface provided with apertures of specified size for carrying out the operation of screening. BS, 5 screened coal Coal that has passed over any kind of a screen and therefore consists of the marketable sizes. screened lump lime Lump lime after forking or screening to remove the finer portion. The portion removed is usually that which will pass a 1/2-in sieve. screened trailing cable A flexible cable provided with a protective screen or screens of tinned copper wire, or other conducting material, applied (1) to enclose each power core separately (individual screening), or (2) to enclose all the cores of the cable (collective screening). BS, 13 screening a. The separation of solid materials of different sizes by causing one component to remain on a surface provided with apertures through which the other component passes. BS, 5 b. Use of one or more screens (sieves) to separate particles into defined sizes. Also called sizing. See also: sieving screening machine An apparatus having a shaking, oscillatory, or rotary motion, used for screening or sifting coal, stamped ores, and the like. screenings a. Fine coal that will pass through the smallest mesh screen normally loaded for commercial sale for industrial use. BCI b. The residue from a screening operation. Nelson screenings crushing A stage in bituminous coal crushing in which units for crushing screenings reduce secondary product to final small, commercial sizes, such as 1- to 3/8-in (2.5- to 1-cm) stoker coal or screenings. Mitchell screen iron ore 2792

Accumulation of surface debris on the lower slopes of iron-bearing hills. The scree material may contain sufficient iron ore to make its mining an economic proposition as at Middleback Ranges of South Australia. Nelson screen loading chute A type of chute with a bar screen or grizzly bottom that permits fines to fall onto the conveyor belt first, providing a cushion for the large material that passes over the screen. screen overflow That portion of the feed material discharged from the screen deck without having passed through the apertures. BS, 5 screen pipe A perforated pipe lined with fine-mesh screen, set in portions of a borehole where the walls must be supported and the ingress of water or oil cannot be restricted. Also called well point. Long screen plate a. A metal plate with specific-sized openings used to control the fineness of grinding in dry pans and hammer mills. ACSG, 2 b. A plate provided with apertures of specified size for use as a screen deck. BS, 5 screen room That part of a breaker where boys picked slate and bony. Korson screens Wire meshes with specific-sized openings for grading particles of various sizes. See also: vibrating screen screen size A standard for determining the size of particles. The particles are passed through screens with openings of specified size. The size of the particles is determined by the size of the opening through which the particles will not pass. Long screen sizing Separating various-sized grain into portions, by a screen or sieve. Also called screening; sizing. 2793

screen underflow That portion of the feed material that has passed through the apertures in a screen deck. BS, 5 scree plate Scot. An iron plate at the foot of a screen on which screened coal is discharged. screw a. The feed screw in the swivel head of a gear-feed diamond drill. Long b. Syn. for an auger stem having helical webs. Long c. A combined symmetry operation involving rotation about an axis and a translation parallel to it. CF: space group d. A crystal defect involving a dislocation about which layers of adatoms spiral during crystal growth. CF: Burgers vector screw bell a. A device to withdraw broken rods from a borehole, when the fracture occurs below a joint. The screw bell is lowered to cut a thread on the end of the broken rod and thus secure a grip sufficient to withdraw it safely. Nelson b. A fishing tool shaped like a bell, bell tap, or bell screw. Long c. See: bell screw; bell socket; bell tap. screw conveyor a. A conveyor screw revolving in a suitably shaped stationary trough, or casing fitted with hangers, trough ends, and other auxiliary accessories. b. A conveyor in which a spiral blade presses material forward as it rotates in a suitable housing. Syn: tubular screw conveyor; spiral conveyor. See also: grit collector; vertical screw conveyor. Pryor, 3 screw-down mechanism That mechanism on a mill for lowering and raising the rolls to accommodate the distance between them to the requirements of the article being rolled. Mersereau, 2 screw elevators Vertical screw elevators are used for handling pulverulent materials. A typical installation for delivering bulk cement into a plant consists of a screw feeder, which takes the cement from the bulk-cement car and feeds it to the screw elevator. Both these units are airtight and all joints are fitted with rubber gaskets that prevent the loss of cement and render the operation dustproof. Pit and Quarry 2794

screw fan See: axial-flow fan screwfeed A system of gears, ratchets, and friction devices, or some combination of these parts, in the swivel head of a diamond drill, which controls the rate at which a bit is made to penetrate the rock formation being drilled. When controlled by a feed gear, the bit maintains the same penetration rate per revolution regardless of drill-stem revolutions per minute. Also called gear feed, mechanical feed. Long screw feeder An auger-type screw to transfer material from one piece of equipment to another. ACSG, 2 screwjack See: jackscrew screw mixer See: screw-type mixing conveyor screw pile A wide helical blade fixed on a shaft and screwed into the ground by means of a winch or capstan. Hammond screwplug See: hoisting plug screw shackle A long cylindrical nut, threaded internally with a right-hand thread at one end and a lefthand thread at the other, used to connect and tighten together the ends of two rods forming a brace or tie. Hammond screw-type mixing conveyor A type of screw conveyor consisting of one or more conveyor screws, ribbon flight or cut flight, conveyor screws with or without auxiliary paddles. See also: blending conveyor; screw conveyor. 2795

scribe An instrument used by surveyors for marking posts, trees, etc. Fay scrin a. Derb. Ironstone in irregular-shaped nodules. b. Derb. A small subordinate vein. Also spelled skrin. scroll A helical projection on a drill rod or stem to remove cuttings from a hole. BS, 12 scronge S. Wales. Overlying strata loosened or broken by workings underneath. Probably a variation of scrunge, to squeeze. scrowl a. Corn. A thin, sometimes calcareous or siliceous rock attached to the wall of a lode. b. Corn. Loose ore at the point where a lode is disturbed by a cross vein. scrubber a. Device in which coarse and sticky ore, clay, etc., is washed free of adherent material, or mildly disintegrated. The main forms are the wash-screen, wash trommel, log washer, and hydraulic jet or monitor. Scrubbers or scrubbing towers are also used to separate soluble gases with extracting liquids, or to remove dust from air by washing. Pryor, 3 b. Device for separating environmentally noxious chemical substances from waste gas streams. scrubstone Eng. A provincial term for a variety of calciferous sandstone. scruff a. A mixture of tin oxide and iron-tin alloy formed as dross on a tin-coating bath. ASM, 1 b. See: scum SCSR See: self-contained self-rescuer 2796

scuffing grind Tumbling of sands with sufficient violence to remove loosely adherent surface coatings without otherwise breaking down the particles to any great extent. Pryor, 3 sculls Incrustations of slag, dross, and metal on the contacting surfaces of vessels that treat or hold molten metals. Pryor, 3 sculp To break slate into slabs suitable for splitting. See also: hard way Webster 3rd; AIME, 1 sculping Fracturing the slate along the grain, e.g., across the cleavage. Zern scum a. Impure or extraneous matter that rises or collects at the surface of liquids, as vegetation on stagnant water, or dross on a bath of molten metal. Sometimes incorrectly used for the word froth in flotation. Fay b. A surface deposit sometimes formed on clay building bricks. The deposit may be of soluble salts present in the clay and carried to the surface of the bricks by water as it escapes during drying; it is then known as dryer scum. The deposit may also be formed during kiln firing, either from soluble salts in the clay or by reaction between the sulfur gases in the kiln atmosphere and minerals in the clay bricks; it is then known as kiln scum. Cf.: efflorescence. Dodd c. Undissolved batch constituents floating as a layer above the molten glass in a pot or tank furnace. Dodd d. Areas of poor gloss on a vitreous enamel; the fault may be due to action of furnace gases, to a nonuniform firing temperature, or to a film clay arising from faulty enamel suspension. Dodd e. The "clouds" appearing around decalcomania formed by varnish residue. ACSG, 2 f. A surface defect appearing as dull patches on otherwise bright surfaces of glazes, glass, or porcelain enamel. ACSG, 2 scun Dev. A small vein. scythestone A whetstone suitable for sharpening scythes. sea 2797

a. An ocean, or alternatively a large body of (usually) salt water less than an ocean. AGI b. Waves caused by wind at the place and time of observation. AGI c. State of the ocean or lake surface in regard to waves. AGI seabeach placers Alaska. Placers adjacent to the seashore to which the waves have access. sea bloom See: plankton bloom sea coal a. Old name for bituminous coal; so named either because it was exported by sea from collieries in coastal districts, or because it was at first applied to coal washed ashore from deposits below sea level. Arkell b. Coal dug from the earth; so called formerly to distinguish it from charcoal, because it was brought to London by sea. Known formerly as pit coal or earth coal. Standard, 2 c. U.S. Rare. Soft coal as distinguished from anthracite. Standard, 2 d. Archaic. Mineral coal. Webster 3rd e. Pulverized bituminous coal used as a foundry facing. Webster 3rd sea current The currents that constitute part of the general oceanic circulation. Syn. for ocean current. Schieferdecker sea-floor trench See: trench sea-foam a. An early syn. for meerschaum. b. See: sepiolite seal a. To secure a borehole or excavation against cave-ins and flowing or escaping gas or liquids by the use of cement or other sealants. Long b. To secure a mine opening against flowing or escaping gas, air, or liquids by injecting grout, by coating rock surfaces with gunite, or by erecting rock, concrete, wood, or cloth barriers. Long c. A short length of roadway that has been tightly filled with concrete, brickwork, sand, or other material to close off an area against fire, gas, or water. In the case of a fire, the seal cuts off the air supply and also prevents noxious fumes given off from reaching other parts of a mine. Also called stopping. See also: firedamp 2798

sealant See: painting Seale construction Wire strand construction having one size of wires for the outer layer with the same number of smaller wires in the underlayer. Both layers have the same length and direction of lay. Hammond sealed area In mining, portion of underground workings sealed off, usually because of fire (in which case no air is allowed to enter) or because no mineable coal remains in the area. See also: unsealing sealed-off area A part of a mine that has been sealed off from the rest of the mine. The object of sealing off a fire area is to: (1) contain the trouble, and to prevent an explosion that may occur inby from extending to other parts of the mine; (2) build up an extinctive atmosphere inside the sealed-off area; and (3) prevent the access of air to the inby side of the seal. Nelson Seale rope A wire rope that has six or eight strands each, having a large center wire covered by nine small wires that are covered in turn by nine large wires. Lewis Seale's lay A wire rope with the inner and outer layers consisting of the same number of wires, the outer being larger and lying in the grooves or valleys between the inner wires. Both layers are stranded or laid in one operation. Extra support is given to the outer wires by this method and the wires are in line contact throughout and there is no internal crosscutting of wires. Sinclair, 5 sea level correction The deduction made from a measured length of a base line to establish its true length at sea level. See also: tape corrections sealing

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a. Shutting off all air from a mine or portion of a mine, a practice used in an emergency to check fire by eliminating oxygen. Also, as a routine shutting-off method for workedout areas in some mines. BCI b. Sealing is used to overcome mine fires when other methods have failed. It involves the erection of temporary or permanent seals for the purpose of cutting off the oxygen supply to the area on fire. Sealing causes the fire to extinguish itself by consuming the oxygen in the sealed off area. Kentucky c. Cutting off the air supply to effect extinction of underground fires by erecting sandbag stoppings at convenient places. The combustion process uses up the available oxygen within the sealed area, the process is arrested and the hot ground cools down gradually as the heat is conducted away by the surrounding cooler strata. See also: fire seal Mason d. Closing pores in anodic coatings to render them less absorbent. ASM, 1 e. Plugging leaks in a casting by introducing thermosetting plastics into porous areas and subsequently setting the plastice with heat. ASM, 1 sealing-wax wood Pieces of wood full of resin found in brown coal. When ignited they burn, melting and giving off soot and an aromatic odor like sealing wax. AGI seal off The use of a cement or other sealant in a borehole. Seal off is not synonymous with blankoff and case off, where securing the walls of a borehole is accomplished by setting pipe or casing. CF: blankoff; seal. Long seam a. A stratum or bed of coal or other mineral; generally applied to large deposits of coal. Fay; BCI b. A particular bed or vein in a series of beds; it is usually said of coal but may also pertain to ore minerals. AGI c. A thin layer or stratum of rock separating two distinctive layers of different composition or greater magnitude. AGI d. A joint, cleft, or fissure. Syn: crevice e. A plane in a coalbed at which the different layers of coal are easily separated. f. A very narrow vein. g. See: joint line seamanite An orthorhombic mineral, Mn3 (PO4 )B(OH)6 ; pale- to wine-yellow; in the Chicagoan Mine, near Iron River, MI. seam contour A line drawn on a plan joining points on the floor or roof of a seam that have the same height above a prescribed datum. BS, 7 seamount 2800

An elevation of the sea floor, 1000 m or higher, either flat-topped (called a guyot) or peaked (called a seapeak). Seamounts may be either discrete, arranged in a linear or random grouping, or connected at their bases and aligned along a ridge or rise. AGI seam-out A shot that merely blows out a soft stratum in the coal or escapes through a seam without loosening the main mass of coal. In Arkansas, called squeal-out. Fay seamy Full of seams, so as to be difficult to blast. search coil a. Sensitive device, using the mine-detector principle, for locating ferromagnetic material that is to be removed before ore treatment. It typically monitors a stream of ore passing along a conveyor belt, which it stops when iron is detected. Pryor, 3 b. Coil that is used in electromagnetic methods for measuring the magnetic field that is associated with the electric current. Schieferdecker search neighborhood Any area searched during interpolation between sample data points. Applies to any interpolation method where a limited number of sample data points are used to estimate intermediate values. searlesite A monoclinic mineral, NaBSi2 O5 (OH)2 ; forms minute spherulites composed of radiating fibers; at Searles Lake, CA. Searles Lake brine A source of trona, Na3 (CO3 )(HCO3 ).2H2 O . Occurs in Searles Lake, San Bernardino County, CA. CCD, 2; Handbook of Chemistry and Physics, 2 sea sand Sand containing alkaline salts that attract and retain moisture and cause efflorescence in brick masonry. Zern sea slick

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An area of sea surface, variable in size and markedly different in appearance, with color and/or oiliness; usually caused by plankton blooms. Hy seasoned Applied to quarrystone after the moisture has dried out. seasoning A mode of treatment of iron castings that are allowed to remain in storage, or to stand out in the open, for a more or less extended period, e.g., 6 months, to effect a reduction in the residual stresses and consequently in the degree of distortion during subsequent machining. A very similar result can often be obtained by a comparatively short period, e.g., 30 min, of tumbling. Since stress relieving by heat treatment is a more certain process, and seasoning involves much delay and the use of considerable space for storage, stress relieving is more usually employed. Osborne seasoning timber The drying of the sap and moisture in the woody fibers and thus reducing the timber by shrinkage. It becomes more durable and weighs less. Timber may be air-dried, i.e., dried naturally in air, or kiln-dried, which means dried in kilns under the action of artificial heat. The former is more general. See also: timber preservation sea state Numerical or written description of ocean surface roughness. Hy seat a. The underclay or fireclay on which a coal seam rests. Also called seating. Arkell b. The foundation or framework on which a structure rests; e.g., engine seat, cage seat. Fay seat clay See: underclay seat earth a. A British term for a bed of rock underlying a coal seam, representing an old soil that supported the vegetation from which the coal was formed; specif. underclay. A highly siliceous seat earth is known locally as ganister. Also spelled: seatearth. Syn: seat rock; seat stone; hard seat. AGI b. A bed representing oil soil, usually containing abundant rootlets, underlying a coal seam. BS, 11 c. The soil on which the coal forests fluorished. 2802

Nelson d. Stratum underlying the valuable seam. Floor of a coal seam. See also: underlying; underclay. Pryor, 3 seated a. Placed in position. Long b. Closed by pressing the closure part of a valve against its seat. Long seating The surface of the point of support for a heavy load. Hammond seat of settlement The deposit of soil under a loaded foundation within which the major settlement occurs. See also: excavation deformation; settlement. Nelson seat rock See: seat earth seat stone See: seat earth sebkainite Crude potassium chloride obtained by solar evaporation of brine from a lake south of Gabes, Tunisia. Hess sebkha See: sabkha secant modulus of elasticity Materials such as concrete or prestressing wire have a variable Young's modulus (E) so that the particular value of E adopted must be either the slope of the tangent to the stressstrain curve or that of the secant. The latter is the line that joins the origin of the curve to, for instance, the 0.1% proof stress, expressed on the curve. For a material within its elastic range, the secant will coincide with the tangent. See also: modulus of elasticity secondarily enriched deposit Deposits that result from supergene enrichment. 2803

Secondary A term applied in the early 19th century as a syn. of Floetz. It was later applied to the extensive series of stratified rocks separating the older Primary and the younger Tertiary rocks, and ranging from the Silurian to the Cretaceous; still later, it was restricted to the whole of the Mesozoic Era. The term was abandoned in the late 19th century in favor of Mesozoic. AGI secondary Said of metal obtained from scrap rather than from ore. secondary air In a combustion chamber, air that meets with primary air to consume the fuel completely and complete combustion. Newton, 1 secondary anomaly See: geochemical anomaly secondary ash Ash in coal derived from mineral matter precipitated in cleat clavities, etc. See also: extraneous ash secondary beam A beam supported off, and transferring loads to, main beams that are themselves carried directly by the walls or columns. Hammond secondary blasting Irrespective of the method of primary blasting employed, it may be necessary to reblast a proportion of the rock on the quarry floor so as to reduce it to a size suitable for handling by the excavators and crushers available. Two methods of secondary blasting of rock are available. The first, called the plaster or mudcap method, is to fire a charge of explosive placed on the rock and covered with clay, the shock of the detonating explosive breaking the block. The second technique, known as pop-shooting, is to drill a hole into the block and fire a small charge in this hole, which is usually stemmed with quarry fines. Also called blistering; bulldozing. See also: plaster shooting; popping; snakeholing; pop shot; boulder blasting. McAdam, 2 secondary cell 2804

A group of flotation cells in which a product from the primary cells is retreated. BS, 5 secondary clay A clay that has been transported from its place of formation and redeposited elsewhere. CF: residual clay; primary clay. See: sedimentary clay secondary consolidation Consolidation of sedimentary material, at essentially constant pressure, resulting from internal processes such as recrystallization. AGI secondary creep Deformation of a material under a constant differential stress, with the strain-time relationship as a constant. CF: primary creep Syn: steady-state creep secondary crusher Crushing and pulverizing machines next in line after the primary crushing to further reduce the particle size of shale or other rock. See also: primary crusher types of jaw crusher and gyratory crusher, and also crushing rolls, hammer mills, and edge runner mills. ACSG, 2; Dodd secondary crushing In ore dressing, the second stage of grinding in which the discharge from the primary crusher is broken down to a size suitable for feed to fine grinding machines. Newton, 1 secondary deposit a. Made when the sediments already deposited are eroded and redeposited. Schieferdecker b. A mineral deposit formed when a primary mineral deposit is subjected to chemical and/or mechanical alteration. Secondary deposits are divided into three groups: sedimentary rocks, secondarily enriched ore deposits, and residual or detrital ore deposits. Hoover secondary dispersion Geochemical dispersion of elements by processes originating at the surface of the Earth; opposite of primary dispersion. Secondary patterns are those formed at the Earth's surface by weathering, erosion, or surface transportation. Secondary patterns have been classified more in detail as halos, fans, and trains, depending on the characteristic shape of the pattern and its geometric relationship to the ore deposit or other source. Hawkes, 1; Lewis 2805

secondary drilling The process of drilling the so-called "popholes" for the purpose of breaking the larger masses of rock thrown down by the primary blast. secondary dust source If an operation agitates or disperses dust, it is a secondary source. See also: primary source secondary enlargement Deposition, around a clastic mineral grain, of material of the same composition as that grain and in optical and crystallographic continuity with it, often resulting in crystal faces characteristic of the original mineral; e.g., the addition of a quartz overgrowth around a silica grain in sandstone. AGI secondary enrichment See: supergene enrichment secondary environment See: geochemical environment secondary fan Any fan installed underground to ventilate tunnels or workings where the air current is sluggish. See also: mine ventilation auxiliary fan; booster fan. Nelson secondary geochemical cycle This cycle is comprised of the processes of weathering, soil formation, erosion, transportation, and sedimentation. Hawkes, 2 secondary grinding Further comminution of material already reduced to sand sizes in rod or ball mills. Pryor, 3 secondary hardness Further increase in hardness produced on tempering high-speed steel after quenching due to precipitation of carbides. CTD 2806

secondary haulage That portion of the haulage system that collects the coal from the various gatheringhaulage delivery points and delivers it to the main haulage system. Wheeler, H.R. secondary lead Lead derived from salvage of wornout end-product items, such as battery plates, cable covering, pipe and sheet, which are collected, remelted, and refined in secondary smelters to produce refined lead or various lead-base alloys. USBM, 7 secondary metal Metal recovered from scrap by remelting and refining. ASM, 1 secondary metal scrap Metal recovered from scrap by remelting and refining. McGraw-Hill, 1 secondary mineral A mineral formed later than the rock enclosing it, usually at the expense of an earlierformed primary mineral, as a result of weathering, metamorphism, or exsolution. AGI secondary mineral deposit A mineral deposit formed when a primary mineral deposit is subjected to alterations through chemical and/or mechanical weathering. Secondary deposits are divided into three groups: sedimentary rocks, secondarily enriched mineral deposits, and residual or detrital mineral deposits. Lewis secondary porosity Porosity developed after the formation of a deposit and resulting from subsequent fracturing, replacement, solution, or weathering. AGI secondary products See: middlings secondary reject elevator A refuse elevator that extracts the second or lighter reject; usually situated at the discharge end of the washbox. BS, 5 2807

secondary rocks Rocks composed of particles derived from the erosion or weathering of preexisting rocks, such as residual, chemical, or organic rocks formed of detrital, precipitated, or organically accumulated materials; specif., clastic sedimentary rocks. AGI secondary settling a. The period following the primary settling in surface subsidence in which the surface subsides gradually. This period may continue for many years or even decades. CF: primary settling b. Residual subsidence. secondary shaft The shaft that extends a mine downwards from the bottom of the primary shaft but not in line with the primary shaft. Spalding secondary shooting In quarrying, the reduction in size or dimension of blasted rock by additional or secondary blasting. Streefkerk secondary splits The main air splits occur at the shaft bottom. In most cases, these splits are again separated at some point inby and these are called secondary splits. See also: ventilation; splitting. Nelson secondary structure A structure that originated after the deposition or emplacement of the rock in which it is found, such as a fault, fold, or joint produced by tectonic movement; esp. an epigenetic sedimentary structure, such as a concretion or nodule produced by chemical action, or a sedimentary dike formed by infilling. CF: primary structure secondary sulfide zone See: sulfide zone secondary twinning Twinning produced subsequent to the original formation of a crystal. secondary vein 2808

A vein discovered subsequent to the one on which a mining claim was based; an incidental vein. CF: discovery vein secondary water Water entering the mine from other workings, as opposed to water inherent in the area worked by the mine. BS, 10 secondary wave See: S wave; transverse wave; distortional wave. second-class lever A lever whose force is exerted between the fulcrum and the point where it is applied. Nichols, 1 second-class ore An ore that needs preliminary treatment before it is of a sufficiently high grade to be acceptable for shipment or market. CF: first-class ore Syn: milling ore second-foot A unit of 1 ft3 /s (0.0283 m3 /s). Usually abbreviated to cusec. Seelye, 1; Hammond second-foot-day The volume of water represented by a flow of 1 ft3 /s (0.0283 m 3 /s) for 24 hours. It is 86,400 ft3 (2,445 m3 ), or nearly 2 acre-feet (actually 1.9835); a convenient unit in storage computations. Seelye, 1 second mining a. The recovery of pillar coal after first-mining in chambers has been completed. Hudson b. The recovery of pillars after development of block pillars by the multiple entry system has completed a panel. second moment of area The correct term for the moment of inertia (I) of the plane area of a section. Hammond second or back explosion

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Aust. Supposed to be due to the ignition of gases developed from highly heated coal dust, and gases sucked out of the faces of coal by the partial vacuum resulting from the primary explosion, or liberated by the fall of roof. CF: retonation wave second outlet An emergency exit from a mine to the surface. Also called second opening; escapeway. Hudson second ripping The first back ripping on a roadway. See also: back brusher Nelson seconds N.S.W. The second-class ore that requires dressing. seconds A.P.I. A unit of viscosity in drilling mud as measured with a Marsh funnel according to American Petroleum Institute procedure. Brantly, 1 second weight In mine subsidence, the powerful thrust or pressure, generally 20 to 40 ft (6 to 12 m) from the face, that causes distance from the roof to the floor to diminish rapidly and for packwalls to become compressed or pushed down into a soft bottom. Timber legs or metal supports (if any) in the gates are generally broken or twisted. Briggs second worker In anthracite coal mining, one who is required to serve a specified number of years before being termed a first-class miner. DOT second working a. The operation of getting or working out the coal pillars formed by the first working. Fay b. In coal mining, unless the pillars of coal are left permanently to support the surface, they are removed. This phase of mining is called the second working or pillar working. When the pillars are removed, nearly all of the coal has been recovered. CF: first working working. See also: working the broken seconite

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A finely ground plastic clay that in proportions not lower than 6% gives satisfactory green strength when used as a bond with molding sand. Osborne secretion a. The act or process by which animals and plants transform mineral material from solution into skeletal forms. AGI b. A secondary structure formed of material deposited from solution within a cavity in a rock, esp. a deposit formed on or parallel to the walls of the cavity; e.g., a mineral vein, an amygdule, or a geode. The space may be completely or only partly filled. CF: concretion sectile a. Capable of being cut with a knife without breaking off in pieces. AGI b. Said of a mineral that can be cut with a knife; e.g., argentite. c. A physical property of minerals permitting shaving of curls with a knife; e.g., gypsum. CF: malleable sectility A mineral is said to be sectile when it may be cut with a knife, but is not malleable, for example, graphite. Nelson section a. A portion of the working area of a mine. BCI b. Representation of features such as mine workings or geological features on a vertical (or inclined) plane. A longitudinal section is parallel to the strike of a vein or geologic plane. A cross section is perpendicular to the strike. McKinstry c. Detailed measurement, taken vertically, of a coal vein or of strata embracing several veins. Hudson d. A drawing or diagram of the strata sunk through in a shaft or inclined plane, or proved by boring. e. The local series of beds constituting a group or formation. Standard, 2 f. A piece of land that is 1 square mile (2.59 km2 ) or 640 acres (259 ha) in area forming one of the 36 subdivisions of a township in a U.S. public-land survey. Webster 3rd sectionalizing circuit breaker See: circuit breaker sectional mining belt conveyor A belt conveyor so arranged that it can be lengthened or shortened by the addition or the removal of interchangeable increments or parts. NEMA, 2 sectional tank 2811

A water tank built up of standardized pressed steel units having external flanges that are bolted together in an assembly for varying sizes of tank. Hammond sectional-type conveyor A conveyor that is lengthened or shortened by adding or removing intermediate sections. NEMA, 1 section boss A more or less loosely used term applied to the assistant mine foreman in charge of an area, although used in law in some states in lieu of assistant foreman and certified as such. BCI section factor See: section modulus section foreman In anthracite and bituminous coal mining, a foreman who has complete charge of a section of a mine. Syn: section man section-gage log See: caliper log section man See: section foreman section modulus The term pertains to the cross section of a beam. The section modulus with respect to either principal central axis is the moment of inertia with respect to that axis divided by the distance from that axis to the most remote point of the section. The section modulus largely determines the flexural strength of a beam of given material. Also called section factor. Roark section of rectifier unit A part of a rectifier unit with its auxiliaries that may be operated independently. Coal Age, 1 sector gate 2812

A roller gate in which the roller is in the form of a sector of a circle instead of being cylindrical. Hammond secular Said of a process or event lasting or persisting for an indefinitely long period of time, e.g., secular variation; progressive or cumulative rather than cyclic. AGI secular variation A relatively large, slow change in part of the Earth's magnetic field caused by the internal state of the planet and having a form roughly to be expected from a simple, but not quite uniformly polarized sphere. AGI secundine dike A dike that has been intruded into hot country rock. Pegmatites and aplites commonly occur in this mode. AGI sedentary Formed in place, without transportation, by the disintegration of the underlying rock or by the accumulation of organic material; said of some soils, etc. Fay sediment a. Solid fragmental material that originates from weathering of rocks and is transported or deposited by air, water, or ice, or that accumulates by other natural agents, such as chemical precipitation from solution or secretion by organisms, and that forms in layers on the Earth's surface at ordinary temperatures in a loose, unconsolidated form; e.g., sand, gravel, silt, mud, alluvium. AGI b. Strictly, solid material that has settled down from a state of suspension in a liquid. In the singular, the term is usually applied to material held in suspension in water or recently deposited from suspension. In the plural, the term is applied to all kinds of deposits, and refers to essentially unconsolidated materials. CF: deposit AGI sedimentary a. adj. Pertaining to or containing sediment; e.g., sedimentary deposit or a sedimentary complex. AGI b. Formed by the deposition of sediment (e.g., a sedimentary clay), or pertaining to the process of sedimentation (e.g., sedimentary volcanism).---n. A sedimentary rock or deposit. AGI sedimentary ash 2813

a. Mineral matter introduced into the coal substance during its accumulation. See also: extraneous ash b. Ash in coal derived from the mud mixed up with plant debris during the formation of coal. Tomkeieff sedimentary clay A clay that has been geologically transported from the site of its formation and redeposited elsewhere. The English ball clays, for example, are secondary kaolins. CF: primary clay Dodd sedimentary cycle See: cycle of sedimentation sedimentary ore A sedimentary rock of ore grade; an ore deposit formed by sedimentary processes, e.g., saline residues, phosphatic deposits, or iron ore of the Clinton ore type. AGI sedimentary petrography The description and classification of sedimentary rocks. Syn: sedimentography sedimentary petrology The study of the composition, characteristics, and origin of sediments and sedimentary rocks. AGI sedimentary rock A rock resulting from the consolidation of loose sediment that has accumulated in layers; e.g., a clastic rock (such as conglomerate or tillite) consisting of mechanically formed fragments of older rock transported from its source and deposited in water or from air or ice; or a chemical rock (such as rock salt or gypsum) formed by precipitation from solution; or an organic rock (such as certain limestones) consisting of the remains or secretions of plants and animals. The term is restricted by some authors to include only those rocks consisting of mechanically derived sediment; others extend it to embrace all rocks other than purely igneous and completely metamorphic rocks, thereby including pyroclastic rocks composed of fragments blown from volcanoes and deposited on land or in water. Syn: stratified rock; derivative rock. AGI sedimentary rocks Rocks formed by the accumulation of sediment in water (aqueous deposits) or from air (eolian deposits). The sediment may consist of rock fragments or particles of various 2814

sizes (conglomerate sandstone, shale); of the remains or products of animals or plants (certain limestones and coal); of the product of chemical action or of evaporation (salt, gypsum, etc.); or of mixtures of these materials. Some sedimentary deposits (tuffs) are composed of fragments blown from volcanoes and deposited on land or in water. A characteristic feature of sedimentary deposits is a layered structure known as bedding or stratification. Each layer is a bed or stratum. Sedimentary beds as deposited lie flat or nearly flat. See: stratified rocks sedimentary tuff a. A tuff containing a subordinate amount of nonvolcanic detrital material. AGI b. A deposit of reworked tuff and other detrital material. AGI sedimentation a. The act or process of settling particles by mechanical means from a state of suspension in air or water. AGI b. Method of classification by exploitation of free-falling rates of minute (subsieve) particles. Pryor, 4 sedimentation balance Apparatus used to measure settling rate of small particles dispersed in liquid. One scalepan is immersed in the mixture, and the balance is adjusted by increasing the counterweight at suitable time intervals. Alternatively, a float is suspended, and the compensating external weight is reduced as the density of the suspension surrounding the float is reduced by settlement of its solids. Pryor, 3 sedimentation test A test used when selecting materials for stabilized road construction and concrete. Soil, after pretreatment, is shaken up in water and allowed to settle out. The change in specific gravity of the suspended matter with time is measured, and the equivalent diameter is calculated from Stokes' law. See also: organic test; Stokes' law. Hammond sedimentation trend The direction in which sediments were laid down. Uranium mineralization often follows such trends, owing to increased porosity, carbon precipitants, and other factors. Ballard sedimentation unit A layer or deposit formed under essentially constant physical conditions, distinguished from other units by differences in grain size and/or fabric, indicating changes in velocity and/or direction of flow. 2815

sediment dispersion The dilution and settling of sediment in a cloud as it advects from a point source. sedimentography See: sedimentary petrography sedimentology The scientific study of sedimentary rocks and of the processes by which they were formed; the description, classification, origin, and interpretation of sediments. AGI sediment tube A long open tube fixed above the core barrel in the shot-drill method of exploratory boring. The enlarged space above the sediment tube reduces the upward velocity of the flushing water and the coarse chippings are deposited in the tube where they are retained until drawn up to the surface. Also called calyx; sludge barrel. Nelson sediment vein A sedimentary dike formed by the filling of a fissure from above with sedimentary material. AGI Seebeck effect The phenomenon involved in the operation of a thermocouple. Named for Thomas Seebeck, the German scientist, who first observed the phenomenon in 1822. See also: thermocouple seed charge A small charge of material added to a supersaturated solution to initiate precipitation. ASM, 1 seed gypsum Gypsum beds of loose small crystals. New South Wales seeding In chemical treatment, addition of tiny crystals of material to a supersaturated solution to induce nuclear precipitation. Pryor, 3 2816

seepage line See: line of seepage Seger cone A small cone, made in the laboratory of a mixture of clay and salt, that softens at a definite, known temperature. It is used in the manufacture of refractories. It has also been used in volcanology to determine the approximate temperature of a molten lava. Syn: pyrometric cone AGI segger See: sagger segregate a. Pac. To separate the undivided joint ownership of a mining claim into smaller individually segregated claims. b. In geology, to separate from the general mass, and collect together or become concentrated at a particular place or in a certain region, such as in the process of crystallization or solidification. See also: segregated vein segregated vein A fissure whose mineral filling is derived from the country rock by the action of percolating water. CF: infiltration vein See also: lateral secretion segregation a. A secondary feature formed as a result of chemical rearrangement of minor constituents within a sediment after its deposition; e.g., a nodule of iron sulfide, a concretion of calcium carbonate, or a geode. AGI b. Partial reseparation of a previously mixed batch of material into its constituents, as a result of differences in particle size or density. Segregation can occur in storage bins, on conveyors, and in feeders during dry or semidry processing. Dodd segregation banding A compositional banding in gneisses that is not primary in origin, but rather is the result of segregation of material from an originally more nearly homogeneous rock. AGI segregation survey The survey of a mining claim located on lands classified as agricultural. 2817

sehta See: cobaltite seidozerite A monoclinic mineral, Na4 MnTi(Zr1.5 Ti0.5 )O2 (F,OH)(Si2 O7 ) ; forms brown-red needles embedded in microcline in a nepheline syenite pegmatite; near Lake Seidozero, Lovozero massif, Kola Peninsula, Russia. seif dune A long, sharp-crested dune extending in the direction of the wind that constructed it. Mather S.E.I. photometer In this instrument, the internal comparison lamp is set to a standard brightness as indicated by a photoelectric cell and not by reference to a voltmeter or ammeter. Roberts, 2 seismic a. Pertaining to, characteristic of, or produced by earthquakes or earth vibration; as, seismic disturbances; seismic records. Standard, 2 b. Pertaining to sound waves generated by earthquakes or artificially by explosives to map subsurface structure. Wheeler, R.R. seismic activity See: seismicity seismic analysis A quick, easy, and inexpensive method of determining the consolidation of overburden. The process is based on the principle that sound or shock waves travel through different subsurface materials at varying speeds and along different paths. By this method the operator can determine whether overburden can be ripped or whether it will need to be drilled and blasted. Coal Age, 3 seismic area The region affected by a particular earthquake. AGI seismic belt 2818

a. One of the broad, more or less well-defined, elongate zones in which most earthquakes originate. Stokes b. An elongate earthquake zone, esp. a zone of subduction or sea-floor spreading. AGI seismic detector See: seismometer seismic diffraction See: diffraction seismic drill See: seismograph drill seismic event Applied to any definite signal change or amplitude difference on a seismic record. It may be a reflection, a refraction, a diffraction, or a random signal. AGI seismic explosives Special forms of blasting gelatin, or gelatin and ammonia gelatin dynamites, used in geophysical prospecting by the seismic method; developed to shoot consistently at their characteristic rate of detonation under unusually heavy water pressure. Lewis seismic focus The place of origin within the Earth of an earthquake; usually some more or less restricted area of a fault surface. If the focus is to be some particular point, it is the central point of the area over which fault movement occurred and caused the earthquake. Challinor seismicity a. Measure of frequency and magnitudes of earthquakes in a given area; e.g., the average number of earthquakes per year and per 100 km2 Schieferdecker b. The phenomenon of earth movements. Hy seismic method A geophysical prospecting method based on the fact that the speeds of transmission of shock waves through the Earth vary with the elastic constants and the densities of the rocks through which the waves pass. A seismic wave is initiated by firing an explosive 2819

charge (or by equivalent artificial sources) at a known point (the shot point); records are made of the travel times taken for selected seismic waves to arrive at sensitive recorders (geophones). There are two main subdivisions of seismic operations: the reflection method and the refraction method. The seismic method has been applied to a lesser extent to elucidate mining problems, partly due to its high cost. It has been used to investigate the base of drift deposits, and drift-filled channels have been successfully outlined. Nelson seismic noise See: microseism. seismic prospecting A method of geophysical prospecting in which vibrations are set up by firing small explosive charges in the ground or by other artificial sources. Precise measurements of the resulting waves are taken, from which the nature and extent of underlying strata are revealed. Hammond seismic reflection method In this geophysical prospecting technique, the structure of subsurface formations is mapped by making use of the times required for a seismic wave (or pulse), generated in the Earth by a near-surface explosion of dynamite or by other artificial sources, to return to the surface after reflection from the formations themselves. The reflections are recorded by detecting instruments responsive to ground motion, which are laid along the ground near the site of generation of the seismic pulse. Variations in the reflection times from place to place on the surface usually indicate structural features in the rock below. Syn: reflection method Dobrin seismic refraction method In refraction shooting, the detecting instruments are laid down at a distance from the shothole that is large compared with the depth of the horizon to be mapped. The seismic waves travel large horizontal distances along distinct interfaces in the Earth, and the time required for travel gives information on the velocity and depth of certain subsurface formations. Dobrin seismic shooting a. The initiation of seismic waves in the rocks by the firing of an explosive charge at a known point. The disturbance must be capable of accurate timing and must be such that, after traveling considerable distances through varying strata, it produces a sharply defined effect on the seismograph. These requirements may be supplied by the shock produced by detonating a charge of high explosive. The intensity of the shock and its 2820

effective range can be controlled by varying the quantity of explosive charge. See also: reflection shooting; refraction shooting. Nelson b. A method of geophysical prospecting in which elastic waves are produced in the Earth by the firing of explosives or by other means. See also: reflection shooting; refraction shooting. AGI seismic shothole A hole drilled for a seismic shot. It is usually a slim hole, although it has also been termed core hole. See also: slim hole; structure test hole. Williams seismic spread See: seismometer spread seismic survey An exploration technique utilizing the variation in the rate of propagation of shock waves in layered media. It is used primarily to delineate subsurface geologic structures of possible economic importance. Long seismic waves The Earth motion produced by a natural (earthquake) or synthetic disturbance on the surface or underground; utilized in the seismic method of geophysical exploration and for investigating the Earth's interior. Three types of waves are produced: (1) longitudinal or P waves; (2) traverse or S waves; and (3) surface or Raleigh and L waves. The speed of propagation is characteristic for each type of rock, depending largely on its compactness. In sandy clay, the speed of the P wave is about 4,000 ft/s (1.22 km/s); in sandstone, 10,000 ft/s (3.05 km/s); and in igneous rock up to 22,000 ft/s (6.71 km/s). Nelson Seismitron An instrument designed to check ground stability. It amplifies 2.5 million times, and can detect a rock movement as small as 0.000001 in (2.54 mu m). Receiving phones are placed in holes in the area being tested. Either earphones or automatic recording apparatus may be used for listening. A rate of 3 or more microseisms per second indicates probable collapse, and any rate over 25 or 30 per minute is considered dangerous. This instrument is also finding use above ground in checking highway cut slopes. Nichols, 1 seismogram The record of Earth motion made by a seismograph. AGI 2821

seismogram synthesis a. This process produces an artificial reflection record from a continuous-velocity log or an electric log. With this system the log is converted from a depth scale to a time scale and is run through a scanning device that transforms the fluctuations on the log into electrical impulses that vary with time so as to simulate reflections. These impulses are passed through appropriate filters and are then recorded on an oscillograph in the same way as signals from a geophone. Dobrin b. The theoretically calculated ground motion that would be recorded for a given Earth structure and seismic source. seismograph a. An instrument that detects, magnifies, and records motions of the Earth, esp. those caused by earthquakes or explosions. The resulting record is a seismogram. CF: seismometer; geophone. AGI b. The instrument used to record the reception of the waves in the sound seismic method. It works on the general principle that its frame is shaken by the arrival of the waves, while a pendulum of high inertia, mounted in it, remains stationary. The relative movement of the frame and the pendulum is magnified by optical means in the seismograph and by electrical amplifiers in the geophone. The instrument can also detect and record earthquakes. See also: geophone; vibrograph. Nelson seismograph drill A rotary drill, pump, and hinged mast mounted as an integral drilling unit on a truck body and used primarily to drill vertical shallow holes in which explosives are placed and detonated to produce shock waves from the rock strata, which then are measured by seismic recording instruments. Also called jackknife rig; rotary shot drill; shothole drill. Syn: seismic drill seismograph rod A collared, tapered, V-thread-coupling drill rod used on seismograph drills. Long seismology a. The science of earthquakes and attendant phenomena. Schieferdecker b. A geophysical science that is concerned with the study of earthquakes and measurement of the elastic properties of the Earth. AGI c. The study of earthquakes, and of the structure of the Earth, by both natural and artificially generated seismic waves. AGI seismometer An instrument that detects Earth motions. Syn: seismic detector CF: geophone; hydrophone; seismograph. AGI 2822

seismometer spacing Distance between successive seismometer positions. Schieferdecker seismometer spread A set of seismometers, placed along a straight line, that record the same shot. Schieferdecker seismoscope An instrument that merely indicates the occurrence of an earthquake. It is considered by some, however, to be the equivalent of a seismometer. AGI seize a. To bind wire rope with soft wire, to prevent it from raveling when cut. Nichols, 1 b. See: bind; freeze. c. To cohere or stick to an inadequately lubricated moving part, such as a bearing, piston, or sliding part, through excessive friction, pressure, or temperature. Long d. To protect rope ends by binding with yarn, marline, or fine wire. Long selected fill Dumped fills made up of selected materials. These fills are used when it is desired to utilize a particular property of a soil or rock and this property can be secured solely by selective excavation. Carson, 1 selective agglomeration In coal beneficiation, the separation of coal from associated impurities, usually aided by additions of oily reagents that selectively attach to the coal surfaces. Generally restricted to material of 500 mu m top size. See also: oil agglomeration selective crushing Crushing in such a manner as to cause one ingredient of the feed to be crushed preferentially to others. BS, 5 selective digging Separating two or more types of soil while digging them. Nichols, 1 selective filling

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Hand filling, during which the miner rejects stone or dirt and loads only clean coal. Similar methods are adopted in metal mining. Nelson selective flotation a. A process for the preferential recovery of a particular ingredient of the coal, e.g., a petrological constituent, by froth flotation. BS, 5 b. Generally refers to the surface or froth selecting of the valuable minerals rather than the gangue. Sometimes used to mean differential flotation. See also: flotation; preferential flotation. Fay selective grinding Grinding in such a manner as to cause one ingredient of the feed to be ground preferentially to others. BS, 5 selective mining a. A method of mining whereby ore of high value is mined in such a manner as to make the low-grade ore left in the mine incapable of future profitable extraction. In other words, the best ore is selected in order to make good mill returns, leaving the low-grade ore in the mine. Frequently called robbing a mine. CF: bulk mining b. The object of selective mining is to obtain a relatively high-grade mine product; this usually entails the use of a much more expensive stoping system and high exploration and development costs in searching for and developing the separate bunches, stringers, lenses, and bands of ore. In general, selective methods are applicable where the valuable sections of the deposit are rather large, comparatively few in number, and separated by relatively large volumes of waste. Selective methods of stoping are square-set stoping, open stoping in low-dipping beds, and cut-and-fill stoping. c. In coal mining, selective methods may be dictated by market demands and prices. It may be desirable to work the different quality coal seams in such proportions as to obtain a uniform and salable blend over a period of years. In metal mining, the stopes may be restricted in both length and width and thus produce a much higher grade of ore. It is not always practicable to resort to selective mining because the mineralization may be so distributed as to necessitate taking the whole orebody in mining operations. Nelson selective reflection The reflection by a substance, such as an opaque gem, of light rays of only certain wavelengths, the others being absorbed. This cause of color in gems is a sort of selective absorption. selective weathering See: differential weathering 2824

selective wetting In mineral processing, development of selective attraction to the water phase of a pulp, as a prelude to flotation of an air-attracted fraction of the contained minerals. Pryor, 3 selectivity index Criterion of trend in a continuous operation such as mineral processing. Abbrev., S.I. Pryor, 3 selector In copper smelting, a kind of converter with horizontal tuyeres, to produce bottoms and a purified copper in one operation. Webster 3rd select round Sometimes used to designate the best quality of industrials normally used as drill diamonds. Long selenite a. Finely crystallized gypsum. Cooper b. A clear, colorless variety of gypsum, occurring (esp. in clays) in distinct, transparent monoclinic crystals or in large crystalline masses that cleave easily into broad folia. Syn: spectacle stone selenite plate In mineralogy, a plate of selenite that gives a purplish-red interference color of the first order with crossed polars. Syn: gypsum plate; unit retardation plate; sensitive-tint plate; first-order red plate; Red I plate; Rot I plate. selenium A nonmetallic element and member of the sulfur family. Symbol, Se. It is widely distributed in small quantities, usually as selenides of heavy metals. Obtained from electrolytic copper refining. Used in photocells, exposure meters, and solar cells, and extensively in rectifiers. Handbook of Chemistry and Physics, 3 selenjoseite See: laitakarite selenolite 2825

a. Wadsworth's name for rocks composed of gypsum or anhydrite. Fay b. A mineral, Pb2 (SeO4 )(SO4 ) , reported as white needles with cerussite and molybdomenite at Cacheuta, Argentina. Dana, 2 c. Former name for olsacherite. d. Discredited name for downeyite, SeO2 . self-act See: gravity haulage self-acting door A ventilation door consisting of two halves, so constructed that they are forced apart centrally by the trams as they come in contact with the converging beams that operate them. The door halves move on small pulleys that run on inclined rails so that after the passage of the trams the door closes by gravity. Nelson self-acting incline a. In transport by mine car, a brake incline. See also: brake incline Pryor, 3 b. See: gravity haulage self-acting plane An inclined plane upon which the weight or force of gravity acting on the full cars is sufficient to overcome the resistance of the empties; in other words, the full car, running down, pulls the other car (empty) up. self-acting rope haulage A system of rope haulage used for transporting material on the surface and to transfer loaded cars from one elevation to a lower one in mines. Slope must be sufficiently steep so the loaded cars will pull the empty cars up the grade. Syn: gravity plane rope haulage self-advancing supports An assembly of hydraulically operated steel hydraulic supports, on a longwall face, that are moved forward as an integral unit by means of a hydraulic ram coupled to the heavy steel face conveyor. Syn: power-operated supports; walking props. See also: hydraulic chock; steel prop. Nelson self-aligning carrying idler A belt idler that controls and limits the side runout of the carrying belt within practical limits by means of a swivel mechanism. NEMA, 2 2826

self-aligning return idler A belt idler that controls and limits the side runout of the return belt within practical limits by means of a swivel mechanism. NEMA, 2 self-annealing A term applied to metals, such as lead, tin, and zinc, that recrystallize at air temperature and in which little strain hardening is produced by cold working. CTD self-centering chuck A drill chuck that, when closed, automatically positions the drill rod in the center of the drive rod of a diamond-drill swivel head. Long self-cleaning tail pulley A conveyor belt structure tail pulley which is designed with vanes along the length of the tail pulley and often is hollow in the center to allow any spillage along the return belt to end up at the tail pulley, which allows it to fall to the sides to eliminate the debris. self-cleansing gradient The gradient at which flow in a pipe of a particular diameter will carry away any solids in it. This gradient must not be too steep nor too gradual, and is usually established under local laws affecting drains and sewers. Hammond self-contained breathing apparatus A self-sufficient breathing unit that permits freedom of movement, unencumbered by air hoses. It offers the wearer respiratory protection in atmospheres that are either oxygendeficient or too highly toxic to permit the use of gask masks or respirators. The oxygen or air is supplied in compressed form or by chemical generation, and the wearer's exhalations are either purified for re-use or released to the surrounding atmosphere. The equipment is devised to afford protection for special lengths of time, in accordance with the standards set by the Mine Safety and Health Administration. The 2-h apparatus is used for mine rescue and recovery operations; shorter period apparatus is available for industrial uses and auxiliary equipment. Best, 1 self-contained portable electric lamps Electric lamps that are operated by an electric battery; designed to be carried about by the user of the lamp. Fay self-contained self-rescuer 2827

A respiratory device used by miners for the purpose of escape during mine fires and explosions; it provides the wearer a closed-circuit supply of oxygen for a minimum of 10 min and up to 1 h. Syn: SCSR self-diffusion The spontaneous movement of an atom to a new site in a crystal of its own species, such as a copper atom within a crystal of copper. ASM, 1 self-dumping cages Cages in which the cars are generally fitted with end doors; the cage deck is pivoted, and a roller engages with a tipping guide at the surface. As the cage is lifted, toward the end of the wind the deck tilts, the end door is lifted, and the coal is discharged. Sinclair, 5 self-dumping car A mine car that can be side-tipped while in motion on a rail track. A ramp structure is fitted alongside the track opposite the spot where tipping is required. The car is fitted with a spherically contoured wheel that engages the ramp and gradually tilts the car while in motion. A chain attachment to the underframe opens the side of the car when tilted for tipping. The ramp can be retracted when not required. Nelson self-energizing brake A brake that is applied partly by friction between its lining and the drum. Nichols, 1 self-feeder An automatic appliance for feeding ore to stamps or crushers without the employment of hand labor. Fay self-feeding portable conveyor Any type of power-propelled conveyor designed to advance into a pile of bulk material, thereby automatically feeding itself. self-fluxing ores Ores that contain both acid and basic gangue minerals in the proper ratio to form a suitable slag. Newton, 1 self-inductance

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The property of a circuit whereby self-induction occurs. It is measured by the rate of change of linkages in a circuit that accompanies a rate of change of current in that circuit of one unit per second. CTD self-issue system A system of storage in lamp-room-operation charging and issue for alkaline-type car lamps, that allows a user access only to the storage racks for the purpose of lamp collection or return. Charging is controlled by a lamp-room attendant. BS, 13 self-loading dumper A dumper provided with a bucket, hinged by arms to the chassis, that scoops up the material and discharges it backwards into the hopper. Hydraulic rams control the lift arms, bucket movement, and dumping operation. Nelson self-opening reamer An underreamer having cutters that expand when they come in contact with, and are pressed against, surface. CF: expansion bit; underreamer. Long self-potential See: spontaneous self-potential curve See: spontaneous potential curve self-potential log Strip recording of natural potentials of complex origin, arising in the immediate neighborhood of liquid-filled boreholes. See also: electric logging self-potential method An electrical exploration method in which one determines the spontaneous electrical potentials (spontaneous polarization) that are caused by electrochemical reactions associated with clay or metallic mineral deposits. Syn: spontaneous-potential method self-potential prospecting A method of electrical prospecting based on the measurement of natural earth potentials caused by the self-potential effects from orebodies, commonly metallic sulfides. AGI 2829

self-powered scraper A scraper built into a single unit with a tractor. Nichols, 1 self-priming centrifugal pump A pump of the centrifugal type that combines in a single hydraulic stage and with a single hydraulic impeller and casing the dual ability to pump, under vacuum, either liquids or gases. These pumps are advantageously used for sump, bilge, mine water gathering, tankcar unloading, vacuum evaporator applications, chemical processing, and other uses where the liquid is below the pump centerline, or under high vacuum. The suction lift is usually guaranteed at 20 ft (6.1 m) for cold water at sea level. Pit and Quarry self-reading staff A leveling staff, marked with graduations so that an observer looking through the telescope of a level can read the elevation at which his or her line of sight intersects the staff. Hammond self-rescuer A small filtering device carried by a miner underground, either on a belt or in a pocket, to provide the miner with immediate protection against carbon monoxide and smoke in case of a mine fire or explosion. The device is used for escape purposes only because it does not sustain life in atmospheres containing deficient oxygen. The length of time a self-rescuer can be used is governed mainly by the humidity in the mine air; e.g., in moist air it will last for a minimum period of 30 min, and in moderately dry atmospheres, for a period of 1 h or more. See also: Siebe-Gorman self-rescuer self-service system A system of storage and issue for lead-acid-battery-operated lamps, whereby the user has direct access to the charging racks for the purpose of connecting or disconnecting a lamp from the charging circuit. See also: attendance signaling system; lamp room. BS, 13 self-shooter See: booming; flop gate. self stones Fragments of rocks still possessing the original shape and angles, Derbyshire, U.K. self-stowing gate 2830

Applied to an advance gate that carries forward a waste or skip, from 6 to 10 yd (5.5 to 9.1 m) wide, to take all the broken rock produced by the gate rippings. A short face conveyor is usually used to move the coal and dirt as required. The width of the waste is just sufficient for stowing the dirt produced. See also: deepside self-timing anemometer An anemometer that has a timing device incorporated in it. Twenty seconds after being started, the device automatically engages the pointer with the rotating vanes and after an interval of 1 min disengages it. See also: anemometer seligmannite An orthorhombic mineral, CuPbAsS3 , with As replaced by Sb toward bournonite; forms small, lead-gray, complex crystals. sellaite A tetragonal mineral, MgF2 ; colorless; structurally related to rutile. selvage a. The altered, clayey material found along a fault zone; fault gouge. Syn: selvedge b. A marginal zone of a rock mass, having some distinctive feature of fabric or composition; specif. the chilled border of an igneous mass (as of a dike or lava flow), usually characterized by a finer grain or sometimes a glassy texture, such as the glassy inner margins on the pillows in pillow lava. Syn: selvedge; salband. AGI selvedge See: selvage Selvulize system A cold vulcanizing method for use underground. It is simpler and quicker than hot vulcanizing and there is no fire or explosion risk involved. Sinclair, 5 semianthracite The rank of coal, within the anthracitic class of Classification D 388, such that, on the dry and mineral-matter-free basis, the volatile matter content of the coal is greater than 8% but equal to or less than 14% (or the fixed carbon content is equal to or greater than 86% but less than 92%), and the coal is nonagglomerating. ASTM semiarid 2831

Said of a type of climate in which there is slightly more precipitation (25 to 50 cm) than in an arid climate, and in which sparse grasses are the characteristic vegetation. Syn: subarid semiautomatic control A system to control the speed of a winder consisting of a cam-operated rheostat in parallel with a manually operated winder controller, the instantaneous cam position being directly related to the position of a cage in the shaft. If the driver left the manual control in the full-speed position, the cam control and associated closed-loop control would take charge and automatically decelerate the winder to creep speed as the cage approaches the surface. Should the driver still defer the operation of the lever, the winder would stop on the operation of an overwind limit switch. By the introduction of a small switch to initiate the wind and another to terminate the wind, fully automatic operation is possible. See also: automatic cyclic winding semicircumferentor A surveyor's instrument used for setting out land or buildings to any angle and in preliminary survey work generally and made up of a horizontal graduated semicircle that surrounds a compass and is attached to a base with fixed vertical sights at each end and of a movable arm with vertical sights at each end that pivots on the center of the base. See also: surveyor's compass semicontinuous mill One that incorporates some stands in tandem, either for roughing or finishing, an example being a semicontinuous wire rod mill with a continuous roughing train and a looping finishing train. Osborne semicoring bit A noncoring bit that produces a small-diameter core. Long semicrystalline See: hyalocrystalline semidry mining a. Underground work in which humidity of ventilating air is kept low, though moisture is used in drilling to allay dust. Pryor, 3 b. In semidry mining, every effort is made to prevent the ventilating air from picking up moisture in the downcast shafts and in the main ways leading to the workings. In the workings themselves, moisture is added freely in order to reduce dust, and the air rapidly becomes saturated. Spalding 2832

semiduplex process The process consists essentially of pouring molten metal from a primary open-hearth furnace on a heated solid charge of heavy and light alloy scrap (20% to 40% of total). The charge is melted and finished under reducing conditions. There is no boil. Osborne semifusain A coal constituent transitional between vitrain and fusain. It displays gradual disappearance of cell structure, hardness, and yellowish color when observed in thin sections. Same as vitrifusain. Stutzer semifusinite A constituent intermediate between vitrinite and fusinite showing a well-defined structure of wood and sclerenchyma. The cell cavities, either round, oval, or elongated in cross section, vary in size but are generally smaller and sometimes less well defined than those of fusinite. Occurs as lenses and bands of variable thickness, and as small fragments; associated with fusinite, or included in vitrite, clarite, duroclarite, clarodurite, and durite. It often lies as a transition material between vitrinite and fusinite, and the properties lie between those of fusinite and vitrinite; behaves as a semi-inert diluent in carbonization. IHCP semigelatin Dynamite containing both ammonium nitrate as the chief explosive ingredient and a certain percent of blasting gelatin to make it plastic enough to remain in holes directed upward. It is more resistant to water than ammonia dynamite, but less resistant than gelatin dynamite. Lewis semihorizon mining Coal mining that consists of driving cross-measure drifts and developing of the seams. The roads in the seam are equipped with conveyors for transporting coal, and locomotives may be used in the cross-measure drifts when these are horizontal or nearly so. Semihorizon mining may include the longwall-retreating method. Nelson semikilled steel Steel that is incompletely deoxidized and contains sufficient dissolved oxygen to react with the carbon to form carbon monoxide to offset solidification shrinkage. ASM, 1 semiloose

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In an excavation, both rock that is only partially detached from the solid and that rings as solid when struck, and rock being still attached to the solid, but parting from it by incipient shear cracks. Spalding semimetallic pellets See: prereduced iron-ore pellet semimuffle furnace A furnace with a partial muffle, in which the products of combustion come in contact with the ware. ASTM semiopal A loosely used term for common opal, hydrophane, and any partly dehydrated or impure opal, as distinguished from precious opal or fire opal. Syn: hemiopal semiplastic explosives In these types, the quantities of liquid products are insufficient to render the mixture compressible. When packing cartridges, however, the same high density is obtained as with plastic explosives. The proportions of the various constituents are actually so arranged that the spaces between the grains are filled out. The proportions in question are determined entirely according to the constituents selected. Fraenkel semiportable electric equipment Electric equipment that is moved infrequently; e.g., room hoists, room conveyors, and gathering pumps. semiportable electric lamps Electric lamps that are connected to a fixed source of power by a flexible cord whose length limits the movable range of the lamp. semiprecious Of less commercial value than those called precious; applied esp. to such stones as amethyst, garnet, jade, and tourmaline. Webster 3rd semiround nose A bit-crown design, in which the radius of the arc forming the rounded portion of the bit face is equal to or greater than the thickness of the bit wall. Long 2834

semisolid bituminous material Material having a penetration at 77 degrees F (25 degrees C), under a load of 100 g applied for 5 s, of more than 10; and a penetration at 77 degrees F, under a load of 50 g applied for 1 s, of not more than 350. Urquhart semisplint coal a. Coal intermediate between durain coal and clarain coal (duroclarain). Tomkeieff b. A coal in which the proportions of anthraxylon and attritus are more or less equal, but the attritus of which is essentially composed of brown and granular opaque matter in varying proportions. Translucent humic matter, spores, pollens, and finely divided fusain are always present in small proportions. Also known as block coal. CF: bright coal; splint coal. Litton c. A banded coal containing 20% to 30% of opaque attritus and more than 5% anthraxylon. AGI semitrailer A towed vehicle whose front rests on the towing unit. Nichols, 1 semitranslucent A degree of diaphaneity between translucent and opaque. Passes light through edges of cabochons but very little through thicker parts. semitransparent Used to describe mineral when objects may be seen through it but without distinct outlines. semivitreous That degree of vitrification evidenced by a moderate or intermediate water absorption. Also called semivitrified. See also: impervious; nonvitreous; vitreous. ASTM semiwater gas A mixture of carbon monoxide, carbon dioxide, hydrogen, and nitrogen obtained by passing a mixture of air and steam continuously through incandescent coke. Its calorific value is low, about 125 Btu/ft3 (4.66 MJ/m3 ). Osborne semseyite A monoclinic mineral, Pb9 Sb8 S21 ; metallic; soft; sp gr, 5.8. 2835

senaite A trigonal mineral, Pb(Ti,Fe,Mn)21 O38 ; crichtonite group; black; forms rounded crystals and grains in diamond-bearing sands. senarmontite An isometric mineral, Sb2 O3 ; dimorphous with valentinite; resinous; Mohs hardness, 2 to 5; sp gr, 5.2 to 5.3. sengierite A monoclinic mineral, Cu2 (UO2 )2 V2 O8 .6H2 O ; yellow-green. sensible cooling effect The difference between the total cooling effect and the dehumidifying effect. Strock, 2 sensible heat a. Thermal energy, the transfer of which to or from a substance results in a change of temperature. CF: latent heat b. The heat added to a body when its temperature is changed. c. The sensible heat of a body is the heat given off when it cools to ordinary temperature. Newton, 1 sensitive earth fault protection A system of earth fault protection in which the fault current is limited by design to a low value which generally requires amplification in order to operate an earth fault relay. In the case of three-phase alternating-current systems, the limitation of the leakage current may be effected by either (1) inserting a current-limiting device between the neutral point of the system and earth (single-point earthing), or (2) connecting, in each circuit to be protected, all phases, in star, through current-limiting devices, each star point being connected to earth through an earth leakage protective device (multipoint earthing). BS, 13 sensitive explosive See: explosive sensitiveness sensitiveness The property in a high explosive that permits it to be exploded by a shock. The more insensitive an explosive is, the stronger detonator it requires to develop the full strength. 2836

sensitive-tint plate See: gypsum plate; selenite plate. sensitivity a. In explosives, a measure of the ease with which a substance can be caused to explode and its capacity to maintain explosion through the length of a borehole. Nichols, 3 b. The least change in an observed quantity that can be perceived on the indicator of a given instrument. AGI c. The displacement of the indicator of a recording unit of an instrument per unit of change of a measurable quantity. AGI d. The effect of remolding on the shear strength and consolidation characteristics of a clay or cohesive soil. A sensitive clay is one whose shear strength is decreased to a fraction of its former value on remolding at constant moisture content. See also: sensitivity ratio sensitivity ratio A measurement of the sensitivity of a clay to the action of remolding. Hammond sensitivity to propagation Sensitivity to propagation of an explosive can be ascertained by a method called the Ardeer double-cartridge, or ADC, test. The ADC test consists of firing an explosive cartridge with a standard detonator and determining the maximum length of the gap across which the detonation wave will travel and detonate a second, or receptor, cartridge. Both the primer and the receptor cartridges should be of the same composition, diameter, and weight. McAdam, 2 sensor The component of an instrument that converts an input signal into a quantity measured by another part of the instrument. Also called sensing element. Hunt separate system A drainage system in which sewerage and surface water are carried in separate sewers. See also: surface-water drain separate tandem electric mine locomotive See: electric mine locomotive separate ventilation An early term for auxiliary ventilation. Nelson 2837

separating bath a. A vessel containing dense medium in which the feed material is separated on a commercial scale into different fractions according to specific gravity. BS, 5 b. The liquid in a separating bath. BS, 5 separating medium Dense medium of the density required to achieve a given separation. BS, 5 separation The distance between any two parts of an index plane (e.g., bed or vein) disrupted by a fault. See also: horizontal separation; vertical separation; stratigraphic separation. AGI separation coal Eng. Coal that has been prepared by screening or washing. separation density The effective density at which a separation has taken place, calculated from a specificgravity analysis of the products; commonly expressed as either partition density or equal errors cut point (density). BS, 5 separation distances Minimum recommended distance between explosive materials and other materials or specific locations. separation door a. A door to separate the air in an intake airway from that in a return airway and prevent leakage. It is normally constructed with tongued-and-grooved boards secured by battens, and it is built into brick or concrete walls to form an airtight closure of the airway. Separation doors are usually arranged in twos or threes several yards apart, to reduce leakage when workers or cars are passing along the roadway. See also: bearing door; steel separation door; ventilation doors. Nelson b. See: air door separation size A general term indicating the effective size at which separation has taken place, calculated from a size analysis of the product; commonly expressed as either partition size or equal errors size. BS, 5 2838

separation valve Eng. A massive cast-iron plate suspended from the roof of a return airway, through which all the return air of a separate district flows, allowing the air to always flow past or underneath it; but in the event of an explosion of gas, the force of the blast closes it against its frame or seating, and prevents a communication with other districts. separator a. A machine for separating, with the aid of water, suspensions, or air, materials of different specific gravity. Strictly, a separator parts two or more ingredients, both valuable, while a concentrator saves but one and rejects the rest; but the terms are often used interchangeably. b. Any machine for separating materials, such as the magnetic separator for separating magnetic materials from gangue. CF: concentrator c. A screen, esp. a revolving screen, for separating things like stones or coal into sizes. Standard, 2 sepiolite A monoclinic mineral, Mg4 Si6 O15 (OH)2 .6H2 O ; soft; sp gr, 2 but fibrous dry masses float on water; occurs in veins in calcite and in alluvial deposits formed from weathering of serpentine masses, chiefly in Asia Minor, as meerschaum; may be used in making pipes, ornamental carvings. Syn: meerschaum; sea-foam. septaria Plural of septarium. septarian Said of the irregular polygonal pattern of internal cracks developed in septaria, closely resembling the desiccation structure of mud cracks; also said of the epigenetic mineral deposits that may occur as fillings of these cracks. AGI septarian concretion See: septarium septarian nodule See: septarium septarium a. A large, roughly spheroidal concretion, 8 to 90 cm in diameter, usually of an impure argillaceous carbonate, such as clay ironstone. It is characterized internally by irregular 2839

polyhedral blocks formed by a series of radiating cracks that widen toward the center and that intersect a series of cracks concentric with the margins; these cracks are invariably filled or partly filled by crystalline minerals (most commonly calcite) that cement the blocks together. Its origin involves the formation of an aluminous gel, case hardening of the exterior, shrinkage cracking due to dehydration of the colloidal mass in the interior, and vein filling. The veins sometimes weather in relief, thus producing a septate pattern. Syn: septarian nodule; septarian concretion; beetle stone; turtle stone. AGI b. A crystal-lined crack or fissure in a septarium. Pl: septaria. AGI septechlorite An alternate name for serpentine minerals reflecting their 7Aa basal spacing and chloritelike formulae. septum Membrane separating two phases, for example, pulp and filtrate. Pryor, 3 sequence control A method of control whereby, once action has been initiated, a number of electrical circuits will automatically function in a prescribed order. BS, 13 sequence interlock An interlock provided between a number of manually controlled electrical circuits, which are required to function in a prescribed order, and which prevents a circuit from being operated unless the preceding circuit has completed its part in the sequence. BS, 13 sequence starting An arrangement whereby the starting of one belt conveyor starts all of its feeder conveyors in a predetermined manner. The purpose of sequence starting is to prevent spilling at transfer points and to reduce the power demand in starting the system. See also: power sequence; pilot sequence. NEMA, 2 sequester A sequestering agent forms soluble complex ions with a simple ion, thereby inhibiting the activity of that ion. Lowenheim serandite A triclinic mineral, Na(Mn,Ca)2 Si3 O8 (OH) , with Mn replaced by Ca toward pectolite; pink. 2840

serendibite A triclinic mineral, Ca2 (Mg,Al)6 (Si,Al,B)6 O20 ; aenigmatite group; blue. serial samples Samples collected according to some predetermined plan, such as along the intersections of gridlines, or at stated distances or times. The method is used to ensure random sampling. AGI seriate Said of the texture of an igneous rock, typically porphyritic, in which the sizes of the grains vary gradually or in a continuous series. CF: hiatal sericite A white, fine-grained potassium mica occurring in small scales as an alteration product of various aluminosilicate minerals, having a silky luster, and found in various metamorphic rocks (esp. in schists and phyllites) or in the wall rocks, fault gouge, and vein fillings of many ore deposits. It is commonly muscovite or very close to muscovite in composition, but may also include paragonite and illite. See also: muscovite sericitization A hydrothermal, deuteric, or metamorphic process involving the introduction of, alteration to, or replacement by sericitic muscovite. AGI series a. Any number of rocks, minerals, or fossils having characteristics, such as growth patterns, succession, composition, or occurrence, that make it possible to arrange them in a natural sequence. AGI b. A conventional stratigraphic unit that is a division of a system. A series commonly constitutes a major unit of chronostratigraphic correlation within a province, between provinces, or between continents. AGI c. May be applied to intrusive rocks in the same time-stratigraphic sense. Formal series names are binomial, usually consisting of a geographic name (generally but not necessarily with the adjectival ending -an or -ian) and the word Series, the initial letter of both terms being capitalized. See also: igneous-rock series d. An arrangement of electric blasting caps in which the firing current passes through each of them in a single circuit. Nichols, 1 series circuit firing A method of connecting together a number of detonators that are to be fired electrically in one blast. Each detonator is connected to the adjacent detonator to form a continuous 2841

circuit having two free ends that are then connected to the firing cable. In British coal mines, all rounds of shots must be connected electrically in series. This results in large rounds having a high electrical resistance, requiring high voltage at the exploder that, in turn, increases the chance of misfires due to current leakage. See also: parallel circuit firing series firing The firing of detonators in a round of shots by passing the total supply current through each of the detonators. CF: parallel firing BS, 12 series-in-parallel circuit See: parallel blasting circuit; parallel series circuit. series parallel firing The firing of detonators in a round of shots by dividing the total supply current into branches, each containing a certain number of detonators wired in series. BS, 12 series shots A number of loaded holes connected and fired one after the other. In contradistinction to simultaneous firing, where the charges are connected electrically, and are all exploded at one time. Stauffer series ventilation A system of ventilating a number of faces consecutively by the same air current. BS, 8 serpentine a. In petrology, a metamorphic rock serpentinite composed chiefly or wholly of the mineral serpentine. b. A group of common rock-forming minerals having the formula (Mg,Fe,Ni)3 Si2 O5 (OH)4 ; mostly monoclinic, but also orthorhombic; greasy or silky luster; slightly soapy feel; tough conchoidal fracture; commonly compact but may be granular or fibrous (asbestiform); green; invariably secondary, derived by alteration of magnesium-rich silicate minerals (esp. olivines); in both igneous and metamorphic rocks; translucent varieties commonly substitute for jade for ornamental and decorative purposes; fibrous varieties are used for asbestos. c. The mineral group antigorite, clinochrysotile, orthochrysotile, and lizardite. d. In former usage, serpentine and antigorite were mineral species and chrysotile was a variety. See also: kaoliniteserpentine serpentine asbestos 2842

See: chrysotile serpentine cat's-eye See: satelite serpentine jade A variety of the mineral serpentine, resembling bowenite, occurring in China; used as an ornamental stone. CMD serpentine marble See: verde antique serpentine rock See: serpentinite serpentinite A rock consisting almost wholly of serpentine-group minerals, e.g., antigorite and chrysotile or lizardite, derived from the alteration of ferromagnesian silicate minerals, such as olivine and pyroxene. Accessory chlorite, talc, and magnetite may be present. Syn: serpentine rock AGI serpentinization The process of hydrothermal alteration by which magnesium-rich silicate minerals (e.g., olivine, pyroxenes, and/or amphiboles in dunites, peridotites, and/or other ultrabasic rocks) are converted into or replaced by serpentine minerals. AGI serpierite A monoclinic mineral, Ca(Cu,Zn)4 (SO4 )2 (OH)6 .3H2 O ; dimorphous with orthoserpierite; sky-blue. serra See: sierra serrate a. Said of topographic features that are notched or toothed, or have a saw-edged profile; e.g., a serrate divide. Syn: saw-toothed b. Said of saw-toothed contacts between minerals, 2843

usually resulting from replacement; e.g., the serrate texture of megacrysts in contact with plagioclase in igneous rocks. AGI serumite A bonding clay for foundry sands. Osborne service factor A factor by which the specified horsepower is multiplied to compensate for drive conditions. Jackson, 1 service shaft A shaft employed solely for the hoisting of workers and materials to and from underground. Nelson serving a. Fiber cord wrapping around the surface of a wire rope. Hammond b. Corn. A supply of tin ready for smelting. servomechanism An automatic feedback control system for mechanical motion; it applies only to those systems in which the controlled quantity or output is mechanical position or one of its derivatives (velocity, acceleration, and so on). Also known as servo system. McGrawHill, 1 set a. A timber frame used for supporting the sides of an excavation, shaft, or tunnel. Syn: sett b. See: one-piece set; timber set; bench of timbers. c. The distance a pile penetrates with one blow from a driving hammer. Nichols, 1 d. A group of essentially parallel planar features, esp. joints, dikes, faults, veins, etc. AGI e. A train of mine cars; a trip. Fay f. The failure of a rock subjected to intense pressure below the point of rupture to recover its original form when the pressure is relieved. Fay g. The discharge opening of a crushing machine to regulate the size of the largest escaping particle. Pryor, 2 h. To fix a prop or sprag in place. i. To place a diamond in the crown of a bit. Long j. To place casting in a borehole. Long set bit A bit insert with diamonds or other cutting media. Long 2844

set casing The cementing of casing in the hole. The cement is introduced between the casing and the wall of the hole and then allowed to harden, thus sealing off intermediate formations and preventing fluids from then entering the hole. It is customary to set casing in the completion of a producing well. Williams set casing shoe A casing shoe set with diamonds. Often used for a one-shot attempt to drill casing down through overburden to bedrock. Also called casing-shoe bit. Long set copper An intermediate copper product containing about 3.5% cuprous oxide, obtained at the end of the oxidizing portion of the fire-refining cycle. ASM, 1 set i.d. See: set inside diameter set inside diameter The minimum inside diameter of a set core bit. Usually written set i.d. in drilling industry literature. Also called bore; center bore; inside gage. Abbrev. set i.d. Long set o.d. See: set outside diameter set of timber The timbers composing any framing, whether used in a shaft, slope, level, or gangway. Thus, the four pieces forming a single course in the curbing of a shaft, or the three or four pieces forming the legs and collar, and sometimes the sill, of an entry framing are together called a set, or timber set. Zern set outside diameter The maximum outside diameter of a set bit. Usually written set o.d. in drilling industry literature. Also called outside gage. Abbrev. set o.d. Long set reaming shell

2845

A reaming shell, a portion of the outside surface of which has embedded diamonds, diamond-inset inserts, or other cutting media, having a set diameter slightly greater than the standard set size of the bit to which the shell is coupled. Long sett a. A quarryman's term for a square-faced steel tool held in position and struck with a sledge to cause a fracture in a rock mass. b. Corn. A lease; the boundaries and terms of the mining ground taken by the adventurers. See also: set c. A timber frame used in underground support. Also spelled set. Pryor, 3 d. A small rectangular dressed stone of granite, quartzite, or whinstone, used as road paving in localized areas subject to esp. heavy traffic. Hammond setting a. Those runners, sheeting, or poling boards which are held in place by one pair of timber frames supporting the sides of an excavation. See also: timbering; top frame. Hammond b. The timber frames used at intervals in shaft sinking and close-poled behind. Stauffer c. See: heading d. The act of contracting with miners for work to be done. Standard, 2 setting out Marking out on the ground by means of pegs and lines the proposed positions and dimensions of earthworks, masonry, etc. Also called staking out. Syn: laying out setting pattern The geometric arrangement of the inset diamonds in a bit crown. Long setting plug A cylindrical object, having a diameter equal to the inside set diameter of a specific-size bit, used to measure the inside set diameter of a core bit. Long setting ring A ringlike sleeve, the inside diameter of which is the same as a specific set outside diameter of a diamond bit or reaming shell; it is used to check the set diameter of a bit or reaming shell. Also called bit gage; bit ring; gage ring; gaging ring; ring gage; setting gage. Long setting rod A special diamond-drill rod used to set a deflecting wedge in a borehole. Long 2846

setting up a. See: rigging b. In mining, to gather the necessary tools and complete all work preparatory to drilling. Syn: setup c. Hardening of air-setting or hydraulic-setting mortars. d. The act or process of setting a diamond bit. Long settled ground Ground that has ceased to subside over the waste area of a mine and has reached a state of full subsidence. Nelson settlement The lowering of the overlying strata in a mine, owing to extraction of the mined material. See also: subsidence; differential settlement; seat of settlement. AGI settlement date Agreed terms on which payment for a consignment of mineral is made. Pryor, 3 settlement price The last unfulfilled offer to sell at cash price at the close of the second morning on the London Metal Exchange, prevails as the accepted cash price for the metal for the succeeding twenty-four hours. Wolff settler A separator; a tub, pan, vat, or tank in which a separation can be effected by settling. A tub or vat in which pulp from the amalgamating pan or battery pulp is allowed to settle; the pulp is stirred in water to remove the lighter portions. Syn: pug tub settling tank. Fay settling box A box or container in which drill cuttings or sludges are accumulated and coarse materials permitted to settle. Long settling cone A conical tank used to settle coarse solids from the circulating water. BS, 5 settlingite

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A hard, brittle, pale-yellow to deep-red hydrocarbon (H:C about 1.53) in resinous drops on the walls of a lead mine at Settling Stones, Northumberland, U.K. See also: settling stones resin settling pit An excavation through which mine water is conducted in order to reduce its velocity, thus allowing sediment to settle and to be cleaned out from time to time. Also called dredge sump; settling sump (undesirable usage). BS, 10 settling pond A pond, natural or artificial, for recovering the solids from washery effluent. BS, 5 settling sand Drillers' term for friable sandstone that caves into wells and settles around the bit. AGI settling stones resin A resinoid, hard, brittle substance possessing a pale yellow to deep red color, a specific gravity of 1.16 to 1.54, and burning in a candle flame. It was found in an old lead mine in Northumberland, England. See also: settlingite settling tank a. A reservoir or tank into which the return water from a borehole collects and the entrained drill cuttings settle. Long b. A tank in which pulp is held while solids settle from suspension. Also called thickener; settler. Pryor, 3 settling vat A vat in which particles of ore are allowed to settle. Fay settling velocity The rate at which suspended solids subside and are deposited. Syn: full velocity setup a. In surveying, location of theodolite above a station point. Pryor, 3 b. In drilling, location of machine. Pryor, 3 c. See: setting up; rigging; rig; rig-up. set weight 2848

The quantity of diamonds set in a bit, expressed in carats. Long severance a. Separation of a mineral or royalty interest from other interests in the land by grant or reservation. A mineral or royalty deed or a grant of the land reserving a mineral or royalty interest, by the landowner before leasing, accomplishes a severance, as does his execution of an oil and gas lease. Williams b. See: liberation severance tax A State tax imposed on the severing of natural resources from the land based on the value or quantity of production. These types of taxes are usually calculated either as a flat rate per unit of production (sometimes called a "unit" or "specific" severance tax), or as a percentage of the value of the resource produced (sometimes called an "ad valorem" or "percentage" severance tax). The tax base for an ad valorem severance tax is generally either the gross or net value of resources produced or sold. SME, 1 severed lands These are lands where the surface estate is held by one party and the mineral estate is held be another. The owner of the mineral estate normally retains the right to enter and occupy the surface estate for the purposes of mineral development and extraction. Also called Split Estate Lands. SME, 1 seyberite See: clintonite seybertite A former name for clintonite. Seyler's classification A classification of coals based primarily upon the carbon and hydrogen content calculated to a pure-coal basis, according to the Parr formula. See also: carbon-hydrogen ratio shackle a. A connecting link or device for fastening parts together, usually in such a manner as to permit some motion. Crispin b. A connecting device for lines and drawbars consisting of a U-shaped section pierced for cross bolt or a pin. Nichols, 1 c. A short wrought-iron or 2849

manganese-steel chain for connecting mine cars to form a journey or train, for transport by rope haulage or locomotive to and from the workings. Syn: coupling Nelson shackler A person employed to attach and detach the shackles between mine cars either at a junction near the face or at the pit bottom. Cars are attached at the junction to form trains for the locomotive or rope haulage. Another shackler detaches them at the pit bottom for loading into the cage. Syn: offtake lad shadd a. Corn. Smooth, round stones on the surface, containing tin ore, and indicating a vein. b. See: shoad shade a. A color that has been darkened by the addition of black. Hansen b. A term descriptive of that difference between colors resulting from a difference in luminosity only, the other color constants being essentially equal. A darker shade of a color is one that has a lower luminosity. Hess shading A method of showing relief on a map by simulating the appearance of sunlight and shadows, assuming an oblique light from the northwest so that slopes facing south and east are shaded (the steeper slopes being darker), thereby giving a three-dimensional impression similar to that of a relief model. The method is widely used on topographic maps in association with contour lines. AGI shadow zone a. Region in which refraction effects cause exclusion of echo-ranging sound signals. Hy b. An area in which there is little penetration of acoustic waves. AGI c. A region 100 degrees to 140 degrees from the epicenter of an earthquake where, due to refraction from the low-velocity zone inside the core boundary, there are no direct arrivals of seismic waves. Syn: blind zone shaft a. An excavation of limited area compared with its depth; made for finding or mining ore or coal, raising water, ore, rock, or coal, hoisting and lowering workers and material, or ventilating underground workings. The term is often specif. applied to an approx. vertical shaft, as distinguished from an incline or inclined shaft. A shaft is provided with a hoisting engine at the top for handling workers, rock, and supplies; or it may be used 2850

only in connection with pumping or ventilating operations.. CF: incline b. A brick or stone stack or chimney. Standard, 2 c. The upper zone of a blast furnace. Mersereau, 2 d. See: abyss shaft allowance The difference between the excavation diameter and the finished diameter in the clear; the extra space allowed to accommodate the permanent shaft lining. Nelson shaft bottom See: loop-type pit bottom; pit bottom; single-approach pit bottom. shaft cable a. A specially armored cable of great mechanical strength running down the shaft of a mine. CTD b. See: borehole cable shaft capacity The output of ore or coal that can be expected to be raised regularly and in normal circumstances, per day or week. Nelson shaft casing The structure enclosing the top of a shaft designed to prevent short circuiting of air into or out of the shaft. See also: air lock BS, 8 shaft cave A cave formed primarily of a shaft or shafts. AGI shaft collar See: collar structure shaft deformation bar A useful contrivance for measuring the deformation in the cross section of a shaft. It consists of a length of 1-1/2-in (3.8-cm) pipe fitted at one end with a micrometer and at the other end with a hard steel cone. The micrometer should have a range of 3 to 4 in (7.6 to 10 cm) and should fit into a bushing in the pipe in some manner. It may thus be removed from the bar for safe keeping or during transport. Issacson shaft drilling 2851

The drilling of small shafts up to about 5 ft (1.5 m) in diameter with a shot drill. In Virginia, shafts up to 6 ft (1.8 m) in diameter have been sunk by core drilling. A ring 4 in (10 cm) wide is formed by roller bits similar to oilfield rotary drilling. Six tricone cutters are used, and a large core is formed. A central hole is drilled in the core, and a small explosive charge is fired to break it for removal. In some cases, it is removed bodily by a core catcher. Nelson shaft feeder cable A cable mounted in a shaft to transmit electrical power to the shaft bottom and/or to an intermediate level. BS, 13 shaft foot Scot. The bottom of a shaft. shaft guides See: cage guide; fixed guides; rope guide. shaft-hoist engineer See: hoistman shaft horsepower a. Actual horsepower produced by the engine after deducting the drag of accessories. Also called flywheel horsepower; belt horsepower. Nichols, 1 b. The shaft horsepower of a winding engine is the average load of coal or ore in pounds (kilograms) raised per wind multiplied by the average number of winds per minute (which may be a fraction) multiplied by the depth of the shaft in feet and the product divided by 33,000. Sinclair, 5 shaft house A building at the mouth of a shaft, where ore or rock is received from a mine. Weed, 2 shaft inset The point where a horizontal tunnel intersects a shaft. Syn: mounting See also: inset shaft kip Eng. See: kip shaft lighting 2852

The lighting of shafts at landing stations is often found to be far from ideal. Work in the cages, during loading and unloading, and examination of shaft gear, are facilitated by the provision of fittings to provide a directional flux distribution in such a way that light is thrown forwards from the pit bottom or inset roadway into the shaft area. There must also be adequate illumination on a vertical plane at the shaft inset. Roberts, 2 shaft lining The timber, steel, brick, or concrete structure fixed around a shaft to support the walls. In modern shafts, a concrete lining is generally favored as a permanent shaft support. Nelson shaft mine a. A mine in which the coal seam is reached by a vertical shaft which may vary in depth from less than 100 ft (30 m) to several thousand feet. Kentucky b. A mine in which the main entry or access is by means of a shaft. CF: drift mining shaft mixer See: mixer shaft pillar a. A large area of a coal seam that is left unworked around the shaft bottom to protect the shaft and the surface buildings from damage by subsidence. All roadways in the shaft pillar are narrow, and coal faces are not opened out until the limit line of the shaft pillar is reached. The area of the shaft pillar is considerably greater than the surface area requiring protection. Syn: high pillar pillar. Nelson b. A solid block of ore left around the shaft where it crosses the lode, for protection against earth movement. Pryor, 3 shaft plumbing a. The operation of transferring one or more points at the surface of a vertical shaft to plumb line positions at the bottom of the shaft; a method to ensure that a shaft is sunk in the true vertical line. See also: centering of shaft b. Survey operation in which the orientation of two plumb bobs is measured both at the surface and at depth in order to transfer the bearing underground. See also: Weisbach triangle shaft pocket a. Ore storage, excavated at depth, which receives trammed ore pending removal by skip. Pryor, 3 b. Loading pockets of one or more compartments for different classes of ore and for waste built at the shaft stations. They are cut into the walls on one or both sides 2853

of a vertical shaft or in the hanging wall of an inclined shaft. See also: pocket c. See: measuring chute shaft raising See: raising shaft section A drawing or log giving details of the structure and the nature of strata intersected by a shaft. BS, 7 shaft set a. Supporting frame of timber, masonry, or steel that supports the sides of a shaft and the gear. Composed of two wallplates, two end plates, and dividers that form shaft compartments. Pryor, 3 b. A system of mine timbering similar to square sets. The shaft sets are placed from the surface downward, each new set supported from the set above until it is blocked in place. New wallplates are suspended from those of the set above by hanging bolts. Blocking, wedging, and lagging complete the work of timbering. At stations the shaft posts are made much longer than usual to give ample head room for unloading timber and other supplies. Lewis shaft siding The station or landing-place arranged for the full and empty tubs at the bottom of the winding shaft. Peel shaft signal Code of electric ringing, or for shallow depths, knocking, among the onsetter or hitcher at the shaft bottom, the banksman at the top, and the engineman who operates the winder. Signals inform the latter as to type of load, etc. A telephone is also installed. Pryor, 3 shaft signal indicator A device, usually mounted in the winding engine house, which gives visual indication of the signals received from the banksman and the onsetter to regulate the movement of conveyances in a shaft, and that retains the indication until cancelled. BS, 13 shaft signal recorder A device that records, on paper or otherwise, the signals given by the banksman and the onsetter and the movements of the winder drum. BS, 13 2854

shaft sinking a. Excavating a shaft downwards, usually from the surface, to the workable coal or ore. High sinking rates are possible by (1) mechanical mucking, (2) increased winding capacity, (3) improved concrete supply and placing, (4) improved surface layout, and (5) improved methods of blasting. Nelson b. Excavating a shaft with a shaft-sinking drill. CF: raise shaft-sinking drill A large-diameter drill with multiple rotary cones or cutting bits used for shaft sinking. An adaptation from oil well drills. Eng. Min. J., 3 shaft-sinking power supply A supply of compressed air at a working pressure of about 100 psi (690 kPa). The quantity required for a modern high-speed sinking may be 2,000 to 2,500 ft3 /min (56.6 to 70.7 m3 /min). At a new mine where two shafts are being sunk, the power installation may comprise eight slow-speed water-cooled compressors with a total output of almost 5,000 ft 3 /min (141.5 m3 /min) at 100 psi. Nelson shaft-sinking ventilation The ventilation of a sinking shaft is by means of auxiliary fans. Axial flow fans powered by flameproof motors are commonly used. Nelson shaft space An opening created with the object of relieving pressure on the shaft. Higham shaft spragger In anthracite and bituminous coal mining, a laborer who controls the movement of mine cars as they are run to the top or to the bottom of the shaft by poking sprags (short metal or wooden rods) between the spokes of the wheels. DOT shaft station An enlargement of a level near a shaft from which ore, coal, or rock may be hoisted and supplies unloaded. shaft survey A survey to determine the alignment of a shaft. 2855

shaft tackle See: poppet head; headframe; poppet. shaft tunnel N. Staff. Headings driven across the measures from shafts to intersect inclined seams. shaft wall a. The brick or concrete lining in a shaft to support the surrounding ground. The construction of the permanent shaft wall is normally in concrete with reinforcement at insets and in bad ground. The wall thickness is between 12 in and 36 in (30 cm and 91 cm) depending on the shaft size and water pressure within the strata. Also applied to the rock masses surrounding the shaft. See also: permanent shaft support Nelson b. The side of a shaft. shag boss In the stonework industry, a foreperson who supervises the removal of waste stone, loading and unloading of finished and semifinished stone, and the moving and piling of stone slabs and blocks at a stoneworking mill. DOT shagreen See: relief shake a. In a coal mine, a vertical crack in the seam and roof. CTD b. Fissures in rock. Arkell c. Minute calcite veins traversing limestone or other rocks containing carbonates. These veinlets, unlike vents, have no harmful effect on the building stone. Arkell d. A cavern, usually in limestone. e. A close-joint structure in rock, due to natural causes, such as pressure, weathering, etc. Used in the plural. shaker A mechanically vibrated screen through which a returning drill fluid is passed to screen out larger chips, fragments, and drill cuttings before the drill fluid flows into the sump. Syn: shale screen; shale shaker. Long shaker chutes Metal troughs, operated mechanically, for the loading of coal into mine cars underground. Hudson 2856

shaker conveyor a. A conveyor consisting of a length of metal troughs, with suitable supports, to which a reciprocating motion is imparted by drives. In the case of a downhill conveyor, a simple to-and-fro motion is sufficient to cause the coal to slide. With a level or a slight uphill gradient, a differential motion is necessary; i.e., a quick backward and slower forward strokes. The quick backward stroke causes the trough to slide under the coal, while the slower forward stroke moves the coal along to a new position. Syn: jigger vibrating conveyor. Nelson b. A type of oscillating conveyor. shaker-conveyor engine A reciprocating engine operated by compressed air which is used to impart the reciprocating motion to a shaker conveyor panline. Jones, 1 shaker screen A screening medium mounted in a rectangular frame, supported in a horizontal or slightly inclined position, and reciprocated longitudinally by a crank or eccentric and connecting rod. The unique feature that differentiates the shaker from all other screens is that the load is made to travel over the screening medium by the shaking motion of the screen. Mitchell shaker-shovel loader A machine for loading coal, ore, or rock usually in headings or tunnels. It consists of a wide flat shovel that is forced into the loose material along the floor by the forward motion of the conveyor. The shaking motion of the conveyor brings the material backwards, and it is loaded into cars or a conveyor. It works at its maximum efficiency to the rise or in flat tunnels. Also called duckbill loader. See also: loader shake wave A wave that advances by causing particles in its path to move from side to side or up and down at right angles to the direction of the wave's advance, a shake motion. Leet, 1 shaking a. See: springing; shaking a hole. b. Corn. Washing ore; ore dressing. shaking a hole The enlargement of a blasthole, by exploding a stick of dynamite, so it will contain a larger amount of explosives for a big blast. Also called a shake blast. See also: springing 2857

shaking conveyor An apparatus that slides under the broken coal and by reciprocating motion moves the coal along to a discharge point. BCI shaking-conveyor loader The broad tapering shovellike end of a shaking conveyor that is thrust suddenly under the coal and slowly withdrawn so as to carry the coal that has been lifted toward the dumping point. Zern shaking down The stirring of an open-hearth bath with a rod to assist in oxidizing and removal of carbon. Henderson shaking screen a. A screen for sizing coal or other material. It consists of a screening surface of punched plate or wire mesh mounted in a rectangular frame, supported in a horizontal or slightly inclined position and reciprocated longitudinally by a crank or eccentric and connecting rod. The slightly inclined shaking screen is favored. Also called jiggling screen. See also: trommel; jigging screen; wet screening. Nelson b. A suspended screen moved with a back-and-forth or rotary motion with a throw of several inches or more. Nichols, 1 shaking table a. In ore dressing, flattish tables oscillated horizontally during separation of minerals fed onto them. Pryor, 2 b. In concentration of finely crushed ores by gravity, a rectangular deck with longitudinal riffles. It is shaken rapidly in a compounded to-and-fro motion by a vibrator, in such a way as to move the sands along, while they are exposed to the sweeping action of a stream of water flowing across the deck, which is tilted about its long axis. In dry or pneumatic tabling the feed is dry, and air is blown upward through a porous deck. Pryor, 3 c. A slightly inclined table to which a lateral shaking motion is given by means of a small crank or an eccentric. One form is covered with copper plates coated with mercury for amalgamating gold or silver; other forms are provided with riffles and used in separating alluvial gold. Syn: jerking table; bumping table. shale a. A fine-grained detrital sedimentary rock, formed by the consolidation (esp. by compression) of clay, silt, or mud. It is characterized by finely laminated structure, which imparts a fissility approx. parallel to the bedding, along which the rock breaks readily into thin layers, and by an appreciable content of clay minerals and detrital quartz; a thinly laminated or fissile claystone, siltstone, or mudstone. It is generally soft 2858

but sufficiently indurated so that it will not fall apart on wetting; it is less firm than argillite and slate, commonly has a splintery fracture and a smooth feel, and is easily scratched. Its color may be red, brown, black, or gray. Etymol: Teutonic, probably Old English scealu, shell, husk, akin to German schale, shell. AGI b. One of the impurities associated with coal seams; this term should not be used as a general term for washery rejects. BS, 5 shale-and-clay feeder One who keeps conveyor belt that feeds dry mill constantly loaded with shale and clay. Also called clay-and-shale feeder; clay feeder; conveyor loader; shale-and-clay-conveyor man; shale feeder. DOT shale band See: dirt band shale break Thin layer or parting of shale between harder strata, primarily a driller's term. CF: shell shale dust The dust obtained by drying and grinding shale. Rice, 2 shalene A term proposed in place of gasoline for that product distilled from oil shale. von Bernewitz shale-off shale Scot. Shale yielding oil on distillation. This term was formerly used as signifying argillaceous rock. shale oil A crude oil obtained from bituminous shales, esp. in Scotland, by submitting them to destructive distillation in special retorts. Fay shale pit A dumping place for coarse material screened out of rotary drill mud. Nichols, 1 shale screen 2859

See: shaker shale shaker a. A cylindrical sieve or vibrating table that removes the drill cuttings from the circulating mud stream. Wheeler, R.R. b. See: shaker shaley blaes Scot. See: bituminous shale shallow ground Aust. Land having gold near its surface. Standard, 2 shallow well A shaft sunk to pump surface water only. See also: well shaly Pertaining to, composed of, or having the character of shale; esp. readily split along closely spaced bedding planes, such as shaly structure or shaly parting. Also, said of a fine-grained, thinly laminated sandstone having the characteristic fissility of shale owing to the presence of thin layers of shale; or said of a siltstone possessing bedding-plane fissility. AGI shamble One of a set of shelves or benches, from one to the other of which ore is thrown successively in raising it to the level above, or to the surface. See also: shammel shammel a. A stage for shoveling ore upon, or for raising water. See also: shamble b. To work a mine by throwing the material excavated onto a stage or bench in the "cast after cast" method, which was the usual way before the art of regular mining by means of shafts had been introduced. Shand's classification A classification of igneous rocks based on crystallinity, degree of saturation with silica, degree of saturation with alumina, and color index. This system was developed in 1927 by S.J. Shand. AGI 2860

shangie Scot. A ring of straw or hemp put round a jumper in boring to prevent the water in the borehole from splashing out. shank a. The steel-threaded portion of a diamond bit to which the crown is attached. Also called bit blank; blank; blank bit. Long b. The body portion of any bit above its cutting edge. Long c. That part of the drill steel which is inserted in the chuck of the drill. Fraenkel d. A bar or standard which connects a rooter tooth with the frame. Nichols, 2 e. A ladle for molten metal, with long handles for use by two or more workers. Webster 3rd Shanklin sand Eng. A marine deposit of siliceous sands and sandstone of various shades of green and yellow gray. Also called Lower Greensand. shaped charge An explosive contained in a case so shaped as to concentrate the power of the explosion in one small area. Shaped charges are used in armor-penetrating weapons, such as the bazooka, for tapping open-hearth furnaces, for cutting deep-well linings, and for breaking boulders. Nichols, 3 shaped stone An artificially blunted or shaped carbon or diamond cut to form a point conforming to a specific profile. Long shape factor Property of a particle that determines the relation between its mass and surface area, and hence its response to frictional restraint. Pryor, 4 shape-firebrick molder One who makes shaped firebricks in steel molds. DOT shape-silica-brick molder One who makes shaped silica bricks in steel molds. DOT shard 2861

a. A vitric fragment in pyroclastics; some have a characteristically curved surface of fracture. Shards generally consist of bubble-wall fragments produced by disintegration of pumice during or after an eruption. AGI b. Syn: sherd sharp fire Combustion with excess air and short flame. ASTM sharp gravel Angular flint gravel. Arkell sharpite An orthorhombic mineral, Ca(UO2 )6 (CO3 )5 (OH)4 .6H2 O ; very radioactive; yellowgreen. sharp sand Sand composed of angular quartz grains, used in making mortar. sharp stone a. Drill diamonds or carbon having sharp edges and corners that have not been artificially blunted or rounded through use. Long b. New-condition, unused carbon or drill diamonds. Long c. A sedimentary rock made up of angular particles more than 2 mm in its greatest dimension. AGI shatter belt A less-preferred syn. of "fault zone." shatter cut See: burn cut shattered zone Applied to a belt of country in which the rock is cracked in all directions, resulting in a network of small veins. shatter index The percentage of a specially prepared sample of coke remaining on a sieve of stated aperture after the sample has been subjected to a standardized dropping procedure. BS, 1 2862

shattery S. Staff. Burnt clay in the vicinity of burnt coal. shattuckite An orthorhombic mineral, Cu5 (SiO3 )4 (OH)2 ; blue. Shaver's disease See: bauxite pneumoconiosis shcherbakovite An orthorhombic mineral, (K,Na,Ba)3 (Ti,Nb)2 Si4 O14 ; dark brown. shear a. A deformation resulting from stresses that cause or tend to cause contiguous parts of a body to slide relatively to each other in a direction parallel to their plane of contact. It is the mode of failure of a body or mass whereby the portion of the mass on one side of a plane or surface slides past the portion on the opposite side. In geological literature the term refers almost invariably to strain rather than to stress. It is also used to refer to surfaces and zones of failure by shear, and to surfaces along which differential movement has taken place. AGI b. See: shearing c. To make vertical cuts in a coal seam that has been undercut. Standard, 2 shear bursts In deep mining fields, shear bursts are the most common type. By the occurrence of a single shear crack parallel to the face in one of the walls, the wall rock behind the shear plane is able to expand freely into the stope, heavily compressing those supports that until then have not taken stress, throwing still more stress on those that have, and causing the wall rock between the nearest supports and the face to disrupt and fill the place with debris. Shear bursts frequently occur at the working face of a pillar, remnant, or promontory. In such cases, they should not be mistaken for true pillar bursts. Spalding shear-cake A counterweighted refractory slab used as a gate or door to a small furnace or oven. ASTM shear cleavage

2863

Refers to cleavage where there is displacement of preexisting surfaces across the cleavage plane by movement parallel to it. Syn: slip cleavage shear cut A vertical cut made by a special type of coal cutter or arc-shearing machine. Syn: vertical cut shearer a. In bituminous coal mining, one who operates a type of coal-cutting machine that shears (cuts) out a channel down the sides of the working face of coal (as distinguished from undercutting) prior to blasting the coal down. Also called shearing-machine operator. DOT b. A person who operates the shearing machine on a longwall face. shearer loader Machine that shears coal or other easily broken mineral from the longwall face of a seam and delivers the broken material continuously to a conveying system. Pryor, 3 shear failure Failure in which movement caused by shearing stresses in a soil mass is of sufficient magnitude to destroy or seriously endanger a structure. Syn: failure by rupture shear fold A fold model of which the mechanism is shearing or slipping along closely spaced planes parallel to the fold's axial surface. The resultant structure is a similar fold. Syn: slip fold shear fracture A fracture that results from stresses that tend to shear one part of a rock past the adjacent part. See also: shear joint CF: tension fracture shearing a. The vertical side cutting that, together with holing or horizontal undercutting, constitutes the attack upon a face of coal. b. Making a vertical cut or groove in a coal face, breast, or block, as opposed to a kerf, which is a horizontal cut. Called in Arkansas a cut or cutting. See also: shear c. Vertical cuts applied in coal headings only to provide an additional free face, since in heading work it is usual to employ deeper cuts than on longwall faces, and the shots in headings are much tighter. McAdam, 2 d. The deformation of rocks by cumulative small lateral movements along innumerable parallel 2864

planes, generally resulting from pressure, and producing schistosity, cleavage, minute application, and other metamorphic structures. shearing force A straining action wherein tangentially applied forces tend to produce a skewing type of deformation. Shear forces are usually accompanied by normal forces produced by tension, thrust, or bending. McGraw-Hill, 2 shearing jib A jib of a coal cutter or cutter loader that makes a vertical or shear cut in the coal, ore, or rock. Nelson shearing machine An electrically driven machine used to cut coal during longwall mining. Usually used in a double-drum configuration. shearing-machine operator See: shearer shear joint Joint that formed as a shear fracture. See also: shear fracture shear lag On account of shear strain, the longitudinal tensile or compressive bending stress in wide beam flanges diminishes with the distance from the web or webs; this stress diminution is called shear lag. Roark shear legs a. A high wooden frame placed over an engine or pumping shaft fitted with small pulleys and rope for lifting heavy weights. Zern b. A tripod on which miners sometimes stand in drilling. Standard, 2 shear modulus Also known as the modulus of rigidity, it equals the shear stress divided by the shear strain. Hammond shear of ore 2865

Ore shoot or orebody. von Bernewitz shearpin A small soft-metal pin, connecting or pinning together two parts of a tool that will break by shearing if an excessive load is placed on the pinned components. The shearing of the pin prevents damage to the overloaded components; thus it is a safety device. Long shear plane A fracture that produces a positive draw. It differs from a weight break in that the character of the fracture is less ragged and heaving takes place over the unwrought coal instead of the waste. Briggs shear rivet Soft copper rivets used in the Hall-Rowe wedge to connect the drive and pilot wedges; they can be sheared off to leave the drive wedge as a permanent reference in the borehole at the point at which the hole is to be deflected. Long shear slide A slide produced by shear failure, usually along a plane of weakness, as bedding or cleavage. AGI shear steel A steel produced by heating blister steel (sheared to short lengths) to a high heat, welding by hammering or rolling, or both, and finally finishing under the hammer at the same or slightly greater heat. Webster 3rd shear strain Angular displacement of a structural member due to a force acting across it, measured in radius. See also: shear modulus shear strength a. The stress or load at which a material fails in shear. Nelson b. A measure of the shear value of a fluid. Also a measure of the gelling properties of a fluid. Brantly, 1 c. The internal resistance of a body to shear stress, typically including a frictional part and a part independent of friction called cohesion. AGI shear stress 2866

a. The shear force operating in a material, measured per unit of cross-sectional area. See also: stress; shear modulus; punching shear. Hammond b. The stress component tangential to a given plane. Also called shearing stress; tangential stress. ASCE shear structure Any rock structure caused by shearing, e.g., crushing, crumpling, or cleavage. AGI shear wave See: S wave shear zone a. A tabular zone of rock that has been crushed and brecciated by many parallel fractures due to shear strain. Such an area is often mineralized by ore-forming solutions. Syn: sheeted zone; sheeted-zone deposit. AGI b. Hogback. Zern sheath a. To enclose or encase with a covering. Carson, 1 b. A chemical compound or mixture incorporated in a sheathed explosive unit that forms a flame-inhibiting cloud on detonation of the explosive. CFR, 4 sheathed explosive A permitted explosive surrounded by a sheath containing a noncombustible powder. The powder acts as a cooling agent and reduces the temperature of the resultant gases of the explosion, and therefore reduces the risk of these hot gases causing a combustible gas ignition. See also: eq sheathed explosive unit A device consisting of an approved or permissible explosive covered by a sheath encased in a sealed covering and designed to be fired outside the confines of a borehole. CFR, 4 sheathing driver Essentially a paving breaker, an impact hammer driven by air, designed and adapted for driving wood sheathing. Carson, 1 sheave Grooved pulley wheel much used in underground rope haulage. See also: Koepe sheave; tail sheave; winding sheave. Pryor, 3 2867

sheave block A pulley and a case provided with a means to anchor it. Nichols, 1 sheave wheel See: sheave shed a. Eng. A thin, smooth parting in rocks, having both sides polished. b. Eng. A very thin layer of coal. c. A divide of land; e.g., a watershed. AGI shedline The summit line of elevated ground; the line of a watershed. sheen a. A subdued and commonly iridescent or metallic glitter that approaches but is just short of optical reflection and that modifies the surface luster of a mineral; e.g., the optical effect still visible in the body of a gem (such as tiger's-eye) after its silky surface appearance has been removed by polishing. b. A luster that emanates from just beneath the surface of a mineral; e.g., opalescence. CF: luster sheep's-foot A tamping roller with feet expanded at their outer tips. Nichols, 1 sheep silver A Scottish term for mica. sheer legs See: shear legs sheet a. A general term for a tabular igneous intrusion, e.g., dike and sill, esp. if concordant or only slightly discordant. CF: intrusive vein AGI b. A term used in the Upper Mississippi lead-mining region of the United States for galena occurring in thin, continuous masses. AGI c. See: blanket sheet deposit 2868

A mineral deposit that is generally stratiform, more or less horizontal, and areally extensive relative to its thickness. AGI sheet drying conveyor A disk type of live roller conveyor equipped with air outlets from a blower to remove dampness from processed sheet metal while being conveyed. sheeted ground a. Several closely spaced parallel faults along which the wall rocks are broken into thin sheets. b. See: shear zone sheeted vein A group of closely spaced, distinct parallel fractures filled with mineral matter and separated by layers of barren rock. sheeted zone See: shear zone sheeted-zone deposit See: shear zone sheeters Light steel poling boards driven down to protect trench sides from collapse. Hammond sheet flow See: laminar flow sheet ground A term used in the Joplin district, Missouri, and applied to horizontal, low-grade, disseminated zinc-lead deposits, covering an extensive area. See also: sheet deposit sheeting a. The development, in rock formations, of small, closely spaced, parallel fractures. b. In a restricted sense, the gently dipping joints that are essentially parallel to the ground surface; they are more closely spaced near the surface and become progressively farther apart with depth. Esp. well-developed in granitic rocks. See also: bedding AGI 2869

sheeting caps A row of caps placed on blocks about 14 in (36 cm) high placed on top of the drift sets when constructing the permanent floor in the stope. Round poles are then laid lengthwise of the stope on the sheeting caps and are covered with lagging. Lewis sheeting driver An air hammer attachment that fits on plank ends so that they can be driven without splintering. Nichols, 1 sheeting jacks Push-type turnbuckles, used to set ditch bracing. Nichols, 1 sheeting pile See: sheet pile sheet iron See: sheet sheet-iron pitch The inclination of a coal seam at which loose coal will not move on the natural bottom, but at which it will slide or can be easily pushed along on iron slides placed on the bottom in the chambers or rooms. Fay sheet jointing See: exfoliation sheet metal See: sheet sheet-metal gage A gage used for measuring the thickness of sheet metal. Crispin sheet mica

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Mica that is relatively flat and sufficiently free from structural defects to enable it to be punched or stamped into specified shapes for use by the electronic and electrical industries. Sheet mica is classified further as block, film, and splittings. Skow sheet pile A pile with a generally flat cross section, which may be meshed or interlocked with adjacent similar members to form a diaphragm, wall, or bulkhead, and designed to resist lateral earth pressure or to reduce ground-water seepage. Syn: sheeting pile sheet piles Closely spaced piles of timber, reinforced concrete, prestressed concrete, or steel driven vertically into the ground to support earth pressure, to keep water out of an excavation, and often to form an integral part of a permanent structure. Hammond sheet-pile wall A wall formed of sheet piles which may be of cantilever design, or anchored back at one or two levels. A retaining wall. Hammond sheet piling A diaphragm made up of meshing or interlocking members of wood, steel, concrete, etc., driven individually to form an obstruction to percolation, to prevent movement of material, for cofferdams, for stabilization of foundations, etc. Seelye, 1 sheet quarry Often used in granite quarrying to designate a quarry having strong horizontal joints and few vertical ones. sheets Eng. Coarse cloth curtains or screens for directing the ventilation underground. Syn: brattice cloth; brattice sheeting. sheet sand A sandstone of great areal extent, presumably deposited by a transgressing sea advancing over a wide front and for a considerable distance. See also: blanket sand sheet structure See: sheeting 2871

Sheffield process A basic open-hearth process using charges so low in sulfur and phosphorus that they could be used in the acid process; the pig iron charged is hematite iron. The charge contains all the elements required to give the required analysis, plus the usual margin of carbon. The charge contains about 0.5% silicon and a maximum amount of manganese, to ensure correct conditions in the bath. Osborne Shelby tube A thin-walled soil-sampling tube, 12 to 30 in (30.5 to 76.2 cm) long, attached to a special rod adapter or sub by means of machine screws. The device is designed to take soil samples by pressing or pushing the tube down into the formation sampled. Syn: Shelby-tube sampler; thin-wall drive sampler. CF: thick-wall sampler; thin-wall sampler. Long Shelby-tube sampler See: Shelby tube shelf a. Corn. The solid rock or bedrock, esp. under alluvial tin deposits. b. Corn. A rock, ledge or rock, reef, or sandbank in the sea. c. Corn. A projecting layer or ledge of rock on land. d. Corn. The submerged border of a continent or of an island extending from the shoreline to the depth at which the sea floor begins to descend steeply toward the bottom of the ocean basin. See also: continental shelf e. Corn. A ledge of bedrock upon which drift rests. Statistical Research Bureau shelf angle A mild steel angle section, riveted or welded to the web of a comparatively deep I-beam supporting the formwork for hollow tiles or forming the seating for precast concrete floor or roof units. Hammond shelf quarry An open pit quarry where the ledge of stone forms a hill and the floor of the quarry worked on a hillside may be little, if any, lower than the surrounding country. In such openings, both transportation and drainage are favorable. AIME, 1 shelf retaining wall A retaining wall of reinforced concrete having a relieving platform built onto its upper part. Hammond 2872

shelf sea The sea overlying the continental shelf. shell a. A thin, hard layer of rock encountered in drilling a well. CF: shale break b. The crust of the Earth. Also, any of the continuous and distinctive concentric zones or layers composing the interior of the Earth (beneath the crust). The term was formerly used for what is now called the mantle. Syn: Earth shell c. A sedimentary deposit consisting primarily of animal shells. AGI d. A steel tube from which air or other gas at high pressure is discharged with explosive force in a shothole; as used with Cardox, Hydrox, and air blasting. BS, 12 e. Incorrectly used by some drillers as a syn. for reaming shell; also incorrectly used as a syn. for the inner or outer tube of a core barrel. Long f. A metal or paper case that holds a charge of powder. Fay g. A group of electrons in an atom, all of which have the same principal quantum number. CTD h. Any thin-wall tubular device. Long i. A torpedo used in oil wells. Fay j. A hollow structure or vessel. ASM, 1 k. An article formed by deep drawing. ASM, 1 l. The metal sleeve remaining when a billet is extruded with a dummy flock of somewhat smaller diameter. ASM, 1 m. In shell molding, a hard layer of sand and thermosetting plastic or resin formed over a pattern and used as the mold wall. ASM, 1 n. A tabular casting used in making seamless drawn tube. ASM, 1 o. A pierced forging. ASM, 1 p. In a grinding mill, external cylinder and ends. Pryor, 3 q. The falling away of a 1- to 2-in (2.5- to 5.1-cm) internal layer of refractory from the roof of an all-basic open-hearth steel furnace; the probable cause is the combined effect of flux migration, temperature gradient, and stress. This form of wear is also known as slabbing. Dodd r. The shell of a hollow clay building block refers to the outer walls of the block. Dodd s. A curved form of plate constuction applicable to roofs. Hammond shell-and-auger boring Method of making exploratory shallow bores in soft ground using an auger for clay and a shell, or sandpump, for sands. Syn: post-hole auger Pryor, 3 shell cameo A cameo carved from shell with raised figure cut from white layers and the background cut away to the darker layers. shell clearance The difference between the outside diameter of a bit or core barrel and the outside set or gage diameter of a reaming shell. Long shelling 2873

See: shell shell lime Lump lime which, when flaked, has a characteristic shell-like appearance. It is used mainly in Scotland. Osborne shell marl a. A sandy, clayey, or limy deposit, loose or weakly consolidated, containing abundant molluscan shells; a common term in the coastal plain of the Southeastern United States. AGI b. A light-colored calcareous deposit formed on the bottoms of small freshwater lakes, composed largely of uncemented mollusk shells and precipitated calcium carbonate, along with the hard parts of minute organisms. AGI shell pump A simple form of sand pump or sludger consisting of a hollow cylinder with a ball or clack valve at the bottom, which is used with a flush of water to remove detritus. See also: sand pump; sludger. Webster 3rd shelly formation A thin and generally hard stratum encountered in drilling. See also: shell shelter hole In coal mining, a niche in the rib along a haulage road into which one may step to avoid passing trains. Also known as a manhole. Shelton loader An adapted coal-cutting machine in which the picks of the cutter chain are replaced by loading flights. The machine hauls itself along the face, the jib leading, by means of an anchored rope. The flights push the prepared coal up a ramp onto the face conveyor, and on their return path to the back of the prepared coal; they fold back and then open up for coal loading as they emerge at the end of the jib. It requires well-prepared coal for successful operation, and will load only in one direction; consequently it has to be flitted back along the coal face. The jib can be swung into line with the body for flitting. Mason shepherd Aust. A miner who preserves legal rights to a claim without working on it. Standard, 2 shepherding 2874

Preserving the rights in a mining claim while doing the minimum possible amount of developing. Nelson sherardize To coat an article of iron or steel with zinc by covering with zinc dust in a tightly closed drum and heating for several hours at 300 to 420 degrees C so that a zinc-iron alloy is formed at the surface through the action of zinc vapor. Webster 3rd sherardizing A galvanizing process in which the metal to be coated is heated, with or without tumbling, in contact with zinc dust. Liddell sherd a. A fragment or broken piece of pottery. AGI b. See: shard sheridanite A variety of clinochlore of the chlorite group. sherry topaz a. A valuable and important variety of topaz the color of sherry wine. b. An incorrect name for citrine of the same color. Sherwen shaker An electromagnetic vibrator used in shaking table mechanisms, concrete consolidation, ore feeders, and screens. Pryor, 3 sherwoodite A tetragonal mineral, Ca9 Al2 V28 O80 .56H2 O ; blue-black. shield a. A framework or diaphragm of steel, iron, or wood, used in tunneling and mining in unconsolidated materials. It is moved forward at the end of the tunnel or adit in process of excavation, and is used to support the ground ahead of the lining and to aid in its construction. AGI b. A large area of exposed basement rocks in a craton, commonly with a very gently convex surface, surrounded by sediment-covered platforms; e.g., Canadian Shield, Baltic Shield. The rocks of virtually all shield areas are Precambrian. Syn: continental shield; cratogene; continental nucleus. AGI c. In longwall mining, the 2875

hydraulically powered roof supports that protect the face workers and advance as the panel is extracted. shield basalt A basaltic accumulation of smaller size than the plateau or flood basalts, arising from the confluence of lava flows from a large number of small, closely spaced volcanoes. CF: plateau basalt Syn: multiple-vent basalt shield volcano A volcano in the shape of a flattened dome, broad and low, built by flows of very fluid basaltic lava or by rhyolitic ash flows. Syn: lava dome; basaltic dome. AGI shift a. A small fault or slip. See also: subsidence b. A fault or dislocation. c. The maximum relative displacement of points on opposite sides of a fault and far enough from it to be outside the dislocated zone. Also called net shift. See also: dip shift; normal shift; strike shift; vertical shift. d. The number of hours or the part of any day worked. Also called tour. Long e. The gang of workers employed for the period, such as the day shift or the night shift. Fay shifter a. In bituminous coal mining, a general term for workers who assist brattice men, repairmen, timbermen, and other workers not engaged in the actual mining of coal. DOT b. See: track shifter shift gear A gear on a gear-feed swivel head of a diamond drill by means of which the feed-shifter rod may be moved to engage the shifter-rod pin into the selected feed gear. Long shifting clothes Street clothes into which the miner changes on emerging from a mine. Korson shift lever A short rod or shaft attached to the shift-gear shaft by means of which the ratio of the driving to the driven gears may be changed in a gear-feed swivel head of a diamond drill or other transmission-gear mechanism. Long shift work 2876

Work performed at a mine and paid for by day wage as opposed to payment by results, namely by tonnage, yardage, or price list. Nelson shinarump See: silicified wood shinbone protectors A form of leggings that protect the shinbone. They are designed in both metal and tough plastic and are secured by leather straps around the legs. Nelson shindle stone Stone from which shindles or roofing slates are made. Local variant of shingle. Arkell shingle a. Coarse, loose, well-rounded waterworn detritus or alluvial material of various sizes; esp. beach gravel, composed of smooth and spheroidal or flattened pebbles, cobbles, and sometimes small boulders, generally measuring 20 to 200 mm in diameter; it occurs typically on the higher parts of a beach. The term is more widely used in Great Britain than in the United States. See also: chingle b. A place strewn with shingle; e.g., a shingle beach. Etymol: probably Scandinavian, akin to singel, coarse gravel that sings or crunches when walked on. AGI shingler A machine for squeezing puddled iron. Webster 3rd shingle structure The arrangement of closely spaced veins overlapping in the manner of shingles on a roof. Syn: imbricate structure shingling In wrought iron manufacture, the operation by which sinter and other impurities are removed from a bloom and the metal solidly welded together by hammering and squeezing. Also called nobbing. Henderson shining As applied to the degree of luster of minerals, means those that produce an image by reflection, but not one well-defined, as celestite. 2877

shin plaster See: suspension ship auger An auger having a simple spiral (helical) body and a single cutting edge, with or without a screw on the end without a spur at the outer end of the cutting edge, used to obtain soil samples in sticky material. Long shiplap liners Longitudinal lining plates for ball mill of wedgelike shape. The thin edge of each wedge underlies the thick edge of the preceding plate in the direction of revolution. Pryor, 3 ship observations Meteorological and oceanographic data taken for a specific location, observed from a ship underway or at anchor. Hy shipper shaft In a dipper shovel, the hinge on which the stick pivots when the bucket is hoisted. Nichols, 2 shipping measure For measuring entire internal capacity of a vessel: One register ton equals 100 ft3 (1.8 m3 ); for measuring cargo; one U.S. shipping ton equals 40 ft3 (1.1 m3 ) or 32.143 U.S. bushels. Crispin shipping ore a. Any ore of greater value when broken than the cost of freight and treatment. b. See: first-class ore shirt The inner lining of a blast furnace. Standard, 2 shiver An old English term for soft and crumbly shale, or slate clay approaching shale. Also spelled chiver. Etymol: Middle English scifre. Adj: shivery. AGI 2878

shiver spar A variety of calcite with slaty structure; specif. argentine. Syn: slate spar shivery post Eng. See: scamy shoad a. Waterworn fragments of vein minerals found on the surface, such as beds of streams, away from the outcrop. Arkell b. Float ore, which has broken from outcrop and gravitated to a distance. Pryor, 3 c. To shoad, to trace a lode by following up shoad. Pryor, 3 d. Corn. Stream tin, or any surface rubble or talus containing fragments of tin, copper, or lead ore, and signifying proximity of a lode. Arkell e. See: shode shoaling effect Alteration of a wave proceeding from deep water into shallow water. The wavelength decreases and the wave height increases. Hy shock bump a. A rock bump caused by the sudden collapse of a thick sandstone or other strong deposit. See also: rock burst; pressure bump. Nelson b. A thump experienced in a mine when the breakage of overlying rocks produces the effect of a hammer blow. Hammond c. See: bumps shock loading In winding, shock loads produced by picking up a cage from the pit bottom with slack chains or by lifting heavy pithead gates or covers. This often causes dry fatigue in the winding ropes. Sinclair, 5 shock losses Head losses resulting from changes in direction of flow or area of duct. They also occur at the inlet or discharge of a system, at splits or junctions of two or more currents of air, and at obstructions in airways. Hartman, 2 shock pressure loss There is a constant ratio between shock pressure loss and the velocity pressure corresponding to the mean velocity of flow. Shock pressure losses can be calculated from the following formula: Ps =XPv , where Ps equals the total shock pressure loss in 2879

inches of water, P v equals the velocity pressure, in inches of water corresponding to the mean velocity of flow (equals approx. [V/4,000]2 at standard air density of 0.075 lb/ft3 or 1.2 kg/m3 ), and X equals an empirical factor or shock factor found by experiment. Ps and P v are expressed in the same units and are equally affected by density. X is therefore independent of both the density and the units used and is the number of velocity pressures equivalent to the shock pressure loss. Roberts, 1 shock-proof As applied to the current-carrying parts of an electric system, excepting trolley wires, is taken to mean that contact with such parts is prevented by the use of grounded metallic coverings or sheaths. shock tube system A system for initiating blasting caps in which the energy is transmitted to the cap by means of a shock wave inside a hollow plastic tube. See also: gas detonation system; nonelectric blasting. Dick, 2 shock wave a. The wave of air and dust that, in some cases, travels ahead of the flame of a coal dust explosion. It may occur when an ignition takes place near the closed end of a mine roadway, and the reaction products behind the flame cannot escape freely. Nelson b. The wave sent out through the air by the discharge of the shot initiating an explosion. The wave travels with the velocity of sound and produces to the human ear a noise like the boom of a cannon. Rice, 2 c. A compressional wave formed whenever the speed of a body relative to a medium exceeds that at which the medium can transmit sound, having an amplitude that exceeds the elastic limit of the medium in which it travels, and characterized by a disturbed region of small but finite thickness within which very abrupt changes occur in the pressure, temperature, density, and velocity of the medium; e.g., the wave sent out through the air by the discharge of the shot initiating an explosion. In rock, it travels at supersonic velocities and is capable of vaporizing, melting, mineralogically transforming, or strongly deforming rock materials. AGI shock-wave compression Nonisentropic adiabatic compression in a wave traveling at greater than local sound velocity. Van Dolah shode a. Corn. A loose fragment of veinstone. Ore washed or detached from the vein naturally. See also: float ore b. Eng. To search for ore by tracing the shode. See also: shoad 2880

shoe a. A trough to convey ore to a crusher. b. A metal block used in a variety of bending operations to form or support the part being processed. ASM, 1 c. A coupling of rolled, cast, or forged steel to protect the lower end of the casting or drivepipe in overburden, or the bottom end of a sampler when pressed into a formation being sampled. Long d. A wearing piece in various types of machines used to break rock, such as a column of drill pipes; bottom of crushing stamp; muller of amalgamating pan. Pryor, 3 e. The lower replaceable part of a gravity stamp which falls on the mineral ore or rock. Nelson shoepite-III See: paraschoepite shoestring claim A mining claim in the form of a long narrow strip. shoestring location A location of a long and narrow strip of mineral land. Ricketts shonkinite A dark-colored syenite composed chiefly of augite and alkali feldspar, and possibly containing olivine, hornblende, biotite, and nepheline. Its name, given by Weed and Pirsson in 1895, is derived from Shonkin, the Indian name for the Highwood Mountains of Montana. AGI shoo-fly a. Miner's work train. Korson b. Any crosscut between a haulageway and airway through which cars are run. See also: pickup; slant. shoot a. See: ore shoot; pipe; blast; chute. Also spelled chute. b. To break coal loose from a seam by the use of explosives; loosely used, also as applied to other coal-breaking devices. BCI c. To break down by airblasting. BS, 12 d. A body of ore, usually of elongated form, extending downward or upward in a vein. Also called ore shoot. Long e. The payable section of a lode; an enriched portion of a continuous orebody. Nelson f. Any considerable and somewhat regular mass of ore in a vein, frequently a rich ore streak in a vein; a chimney; also, a vein branching at a small angle from and reentering the main vein. Standard, 2 g. The valuable minerals are commonly concentrated in certain portions of a vein that have one dimension much longer than the others. This 2881

shoot or chimney of ore is usually highly inclined to the horizontal. Lewis h. To explode a charge in blasting operations. Hudson i. See: blast j. In seismic exploration, the firing of the explosive by an electrical impulse; also, the process of carrying out a seismic survey, to shoot an area or prospect. AGI shooter See: blaster shooting The use of explosives in rock breaking. shooting against the bank See: blanket shooting shooting boat In marine seismic exploration, a boat equipped to carry explosives, and from which the placing and firing of shots are performed. AGI shooting by seismograph The making of a seismographic survey. The term shooting derives from the setting off of explosions in the ground. The shock waves from these explosions are recorded by a seismograph, and from these records a contour map can be made. Williams shooting needle A blasting needle; a metallic rod used in the stemming of a drill hole for the purpose of leaving a cavity through which a charge may be fired. Fay shooting off-the-solid Mining coal by heavy blasting without undermining or shearing it. In England, called shooting fast. Fay shooting on-the-free The use of a smaller charge of powder to blow down the face of the coal after it has been undercut, as distinguished from "shooting off-the-solid". Fay shooting rights 2882

The right to enter upon land and make a geophysical survey. Williams shooting truck In seismic operations, a truck equipped to carry explosives, materials, and equipment for preparing, loading, tamping, and firing explosive charges. AGI shooting valve The control valve provided for the purpose of admitting compressed air to an airblasting shell and of venting residual air, in the shell and hose, to the atmosphere. BS, 12 shop rivet A rivet driven in a workshop, as distinct from a field or site rivet. Hammond shoran A precise electronic measuring system for indicating distance from an airborne or shipborne station to each of two fixed ground stations simultaneously by recording (by means of cathode-ray screens) the time required for round-trip travel of radar signals or high-frequency radio waves and thereby determining the position of the mobile station. Its range is effectively limited to line-of-sight distances (or about 40 nmi or 74 km). Shoran is used in control of aerial photography, airborne geophysical prospecting, offshore hydrographic surveys, and geodetic surveying for measuring long distances. CF: loran navigation. AGI shore drift The coarse material covering the bottom where the agitation of the water at the bottom is effective constitutes shore drift. See also: littoral drift Shore hardness test A scale of hardness of rocks as determined by the Shore scleroscope test. The scale avoids the limitation of Mohs' scale of hardness and gives better assessment of rock hardness. See also: tungsten carbide bit shore reef See: fringing reef Shore scleroscope

2883

An instrument comprising a small diamond-shaped hammer that falls freely down a graduated tube of glass from a constant height. The hardness of the surface under test is measured by the height of the rebound. In one type of this instrument, the rebound of the hammer actuates the pointer of a scale so that the height of rebound is recorded. See also: scleroscope hardness test shore terrace a. A terrace produced by the action of waves and currents along the shore of a lake or sea; e.g., a wave-built terrace. AGI b. Marine terrace. AGI shore up To stay, prop up, or support by braces. shoring Timbers braced against a wall as a temporary support. Also, the timbering used to prevent a sliding of earth adjoining an excavation. Crispin short a. Said of roof shale that tends to break up or crush under pressure into small fragments and that will not hold in any span over a few inches. Also called tender. Raistrick b. Brittle; friable; breaking or crumbling readily; inclined to flake off; said of coal. c. Used to denote a roof that has very little structural strength. TIME short awn A direction of more than 45 degrees to the main natural line of cleat or cleavage in the coal. Also spelled horn. CF: long awn short coal See: short short column A column so short in relation to its cross section that, if overloaded, it will fail by crushing rather than by buckling. CF: long column Hammond short-delay blasting a. A method of blasting where the explosive charges are detonated with a very short delay interval between them. It enables shots to assist one another as in simultaneous 2884

firing, and also each shot or group of shots establishes a free or semifree face for the following group of shots. Nelson b. Method of blasting by which charges are caused to explode in a given sequence with time intervals of 0.001 to 0.1 s. Fraenkel short-delay detonator a. A detonator in which the interval of time delay is incremental in milliseconds. Syn: millisecond-delay detonator b. The original 1-s delay detonators are no longer used, and the choice now lies between the one-half-second type and those known as short-delay detonators. These give better fragmentation of rock and consequently better loading rates. Nelson short-delay electric detonator An electric detonator with a designated delay period of 25 to 1,000 ms. CFR, 4 short-flame explosive See: permissible explosive short hole Taphole in a furnace that is not properly stopped and that is likely to release the molten charge prematurely. Henderson short-hole work Diamond drilling where the length of borehole generally does not exceed 100 ft (30 m). Long short period The time required to drill a few holes for trolley hangers or a few short block holes, or one or two holes for bringing down a piece of loose roof. short-period delay An electric blasting cap that explodes one-fiftieth to one-half second after passage of an electric current. Syn: millisecond delay Nichols, 1 short-range order a. Identical first-neighbor coordination of atoms. Typical of glassy structures. Van Vlack b. A structural state in which cations have coordination polyhedra as predicted by radius ratios but lack the long-range order of crystallinity; e.g., silicate glasses. CF: long-range 2885

order c. The type of order in which the probability of a given type of atom having neighbors of a given type (for example, that an Alpha atom is surrounded by Beta atoms) is greater than would be expected on a purely random basis. There is thus a tendency to form small ordered domains, but these do not link together at long distances. short run To be forced by adverse conditions or core blockage to pull the drill string before the core barrel being used is filled to capacity with core. CF: long run shorts a. As applied to asbestos, consist of the very shortest of classified grades; the fibers may vary from microscopical thin filaments to crude bundles of fibers of appreciable thickness. Included may be particles of nonfibrous serpentine ranging from a palpable powder to granules of visible size. Sinclair, 7 b. The product that is retained on a specified screen in the screening of a crushed or ground material. ASM, 1 c. In gold cyanidation, the oversize after the gold-rich zinc from the precipitation boxes has been rubbed through. Pryor, 3 d. The shortage in production under a royalty lease. CTD short section A section of land according to the U.S. Governmental Survey that contains less than 640 acres. Williams short shot Colloquialism for weathering (or low-velocity layer) shot in seismic prospecting. AGI short-term exposure limit A 15-min time-weighted average exposure that should not be exceeded at any time during a work day even if the 8-h time-weighted average is within the threshold limit value. Abbrev: STEL. ACGIH, 2 shortwall a. The reverse of longwall, frequently used to mean the face of a room. Zern b. A method of mining in which comparatively small areas are worked separately, as opposed to longwall; e.g., room and pillar. BCI c. A length of coal face intermediate between a stall and a normal longwall face. A shortwall face may be any length between about 5 yd and 30 yd (4.6 m and 27 m) and is generally employed in pillar methods of working. Rooms and stables may also be classified as shortwall faces. See also: shortwall development 2886

shortwall coal cutter a. A machine for undercutting coal that has the cutter bar fixed in relation to the main body of the machine. It sumps and cuts across a face in a more or less continuous motion, except when it becomes necessary to stop to change the position of the ropes used to move the machine through the action of rope drums, or when difficulties in cutting are experienced. Jones, 1 b. A coal cutter that has a long, rigid chain jib in line with the body of the machine; it cuts across a heading from right to left, being drawn across by means of a steel wire rope. This machine cannot be readily flitted from one heading to another unless a power-propelled flitting truck is available; otherwise each heading requires its own shortwall cutter. A shortwall cutter will make a 6-ft (1.8-m) cut across a 15-ft (4.6-m) heading in 20 min, including sumping in and out of the cut. Mason shortwall development A system of coal working sometimes employed in seams 4 ft (1.2 m) or under in thickness, with the aid of machines. Short faces, each 15 to 30 yd (13.7 to 27 m) wide, are driven at 50- to 70-yd (46- to 61-m) centers, with crosscuts to assist coal transport and ventilation. The rippings are used to form roadside packs. The shortwalls are driven to the boundary, and the coal pillars are worked by longwall retreating. See also: shortwall shoshonite A trachyandesite composed of olivine and augite phenocrysts in a groundmass of labradorite with alkali feldspar rims, olivine, augite, a small amount of leucite, and some dark-colored glass. Shoshonite grades into absarokite with an increase in olivine and into banakite with more sanidine. Its name, given by Iddings in 1895, is derived from the Shoshone River, WY. AGI shot a. Coal that has been broken by blasting or other devices. BCI b. A single explosive charge fired in coal, stone, or ore. Nelson c. A detonation (or its equivalent) as used in seismic shooting. See also: gouging shot d. Small spherical particles of brittle hard steel used as the cutting agent in drilling a borehole with a shot drill. Also called adamantine shot; buckshot; chilled shot. See also: gripping shot; blast; shot drill. Long shot blasting A method similar to sandblasting for cleansing the surface of metals, using broken shot or steel grit instead of sand. Hammond shot boring 2887

The act or process of producing a borehole with a shot drill. See also: shot drill shot-boring drill See: shot drill shot bort a. Incorrectly used to designate a small spherical-shaped drill diamond. See: drill diamond b. See: ballas c. Variety of bort with little impurity, in milky-white to steel-gray spherical stones with radiating structure and great toughness. Tomkeieff d. Spheres of translucent diamond with more cohesion than ordinary bort. See also: bort shot break In seismic prospecting, a record of the instant of generation of seismic waves, as by an explosion. Syn: time break; shot instant. AGI shot copper Small, rounded particles of native copper, molded by the shape of vesicles in basaltic host rock, and resembling shot in size and shape. AGI shotcrete Gunite that commonly includes coarse aggregate (up to 2 cm). AGI shot datum Seismic calculations are usually reduced to a convenient reference surface or plane. These calculations simulate a condition where the charge is shot on the reference surface and the energy is also recorded on this same reference surface. At this reference surface, the time-depth charts have their origin. AGI shot depth The distance from the surface to the explosive charge. In the case of small charges, the shot depth is measured to the center of the charge or to the bottom of the hole. In the case of large charges, the distances to the top and to the bottom of the column of explosives are frequently given, and may be reduced to effective shot depth to give the equivalent of a concentrated charge. AGI shot drill

2888

A core drill generally employed in rotary-drilling boreholes of less than 3 in (7.62 cm) to more than 6 ft (1.8 m) in diameter in hard rock or concrete, using chilled-steel shot as a cutting medium. Also called adamantine drill; calyx drill; chilled-shot drill. See also: core drill; shaft drilling. Syn: shot-boring drill shot-drilled shaft Shafts of up to 5 ft (1.5 m) in diameter drilled through rock to a maximum depth of 1,200 ft (366 m) by means of a shot drill. The latter makes use of shot for cutting a circular groove in the rock being penetrated, from which solid cores are extracted. Hammond shot elevation a. Elevation of the dynamite charge in the shothole. AGI b. The elevation of the explosive charge in the shot hole. Not to be confused with shothole elevation. AGI shot fast Coal mined by blasting; shot off the solid. shot feed A device to introduce chilled-steel shot, at a uniform rate and in the proper quantities, into the circulating fluid flowing downward through the rods or pipe connected to the core barrel and bit of a shot drill. Long shot firer a. A worker whose special duty is to fire shots or blasts, esp. in coal mines. A shot lighter. Also called a shooter. b. In a coal mine, a qualified miner who tests for gas before firing explosive shots. Pryor, 3 c. See: blaster Shot Firer A multiple-shot permissible blasting unit introduced in 1948, known as Capacitor Type Permissible Shot Firer. Weighing approx. 1 lb (0.454 kg) and about the size of an ordinary flashlight, the nonmetallic unit is equipped with a belt hook which permits its being carried under supervision of the shot firer. If desired, shots can be fired without removing the unit from the belt. It is capacitor operated, eliminating dependence on speed of operation for energy output. Capacitors supply high voltage, for a few milliseconds, more than ample to fire from 1 to 10 electric blasting caps. Kentucky shot firing 2889

a. The action of detonating or igniting a charge of explosive, usually in a drilled hole. BS, 12 b. The firing of an explosive charge in a drilled hole to break the material to a suitable size for loading. Nelson shot-firing blasting cord A two-conductor cable used for completing the circuit between the electric blasting cap (or caps) and the blasting unit or other source of electric energy. Syn: blasting cord shot-firing cable A pair of insulated copper conductors which lead from the exploder to the detonator wires. It may be either twin-core (both conductors contained in the one cable) or singlecore (each conductor contained in a separate cable). Twin-core cables having cores of four strands, each 0.018 in (0.046 cm) in diameter (4/0.018) with a resistance of approx. 5 Omega per 100 yd (91 m), are commonly used. Actual choice of cable must depend upon conditions of use and the relevant regulations. Syn: twin-core shot-firing cable shot-firing cable tests The methods of testing twin-core and single-core cables are identical. Two tests are applied, one for insulation and one for continuity, and where large and important charges are being fired, as in tunnel, wellhole, and quarry blasts, tests are made before every blast. For the cable insulation test, an approved circuit tester or ohmeter is connected to one end of the cable, the two conductors at the other end being separated. No current should flow, and the resistance should be infinite. For the continuity test, the two far ends of the cable should be joined. The tester should show that the current is complete, or if an ohmeter is used, this should show the correct resistance of the shot-firing cable. Nelson shot-firing circuit Extends from the exploder along the shot-firing cable, detonator wires, and finally the detonator. The shot-firing circuit is the path taken by the electric current from the exploder when a shot is detonated. Nelson shot-firing curtain A steel chain mat suspended from the roof about 9 to 12 ft (2.74 to 3.66 m) from the face of an advancing tunnel to limit damage to equipment and danger from flying debris when shot firing at the face. It consists of a steel frame with chains suspended about 6 in (15 cm) apart. See also: blasting curtain shot firing in rounds 2890

The firing of a number of shots in a tunnel, or shaft sinking at one operation with instantaneous or delay detonators. Nelson shot-firing unit See: blasting unit shothole a. A hole drilled for the purpose of shot firing. BS, 12 b. A hole drilled in coal, ore, or rock, usually from 3 to 9 ft (0.9 to 2.7 m) in length (underground), for breaking down the material by means of explosives. Nelson c. The borehole in which an explosive is placed for blasting. See also: blasthole d. See: shot point e. A borehole drilled with a shot drill. Long f. In seismic prospecting, a borehole in which an explosive is placed for generating seismic waves. AGI shothole bridge a. When an obstruction in the shothole makes it difficult or impossible to get the charge deeper, the hole is said to be bridged. A narrow diameter in the hole due to a resistant bed often makes it difficult to get the charge down the hole. A mechanical device that purposely bridges the hole at a shallow depth in order that the hole may be filled. AGI b. An obstruction in a shothole that prevents an explosive charge from going deeper. It may be accidental or intentional. AGI shothole casing Lightweight pipe, usually about 4 in (10 cm) in diameter. A typical joint of casing is 10 ft (3 m) long and has threaded connections on both ends. The primary use of casing is to prevent the shothole from caving and bridging. The lightweight casing may be considered as an expendable item. AGI shothole drill a. Generally, a rotary percussion or auger type drill for making shotholes for blasting. b. Drills for shotholes are of two general types: (1) the rotary drill and (2) the churn drill. Rotary drill methods can be subdivided into (1) mechanical feed and (2) hydraulic feed. Both types provide a means for rotating the pipe, and both make provisions for circulating fluid down through the pipe, thus washing the cuttings away from the bit and conveying them up to the surface in the annular space between the wall of the hole and the string of drill pipe. The churn drill is similar to the larger cable-tool type. It is seldom used except in areas where underground cavities hamper the return flow of the circulating fluid used in the rotary methods. Portable drills, water jets, and airblast equipment and augers are also used in certain areas. Syn: blasthole drill AGI 2891

shothole elevation The elevation of the ground at the top of the shothole. AGI shothole fatigue Phenomenon causing observed travel times to a fixed receiver point to increase with successive shots in the same hole. AGI shothole log The drillers' record of the depths, thicknesses, and lithologic characteristics of the formations encountered in the seismic shothole. AGI shothole plug A plug, usually of wood, used by seismic field parties to plug a hole upon completion of shooting. This prevents caving, protects the public from injury, and protects the exploration company from damage claims that might result from open holes. AGI shot instant The elevation of the explosive charge in the shot hole. Not to be confused with shothole elevation. Syn: shot break; time break; shot moment. AGI shot metal Metal in the form of small, spherical, or nearly spherical, pellets. It is usually made by causing molten metal to fall, dropwise, from a suitable height into a quenching medium. Also called shot. Henderson shot moment See: time break; shot instant. shot-moment line An electric line wrapped around a dynamite charge and connected to a telephone or radio circuit. The explosion breaks the circuit to record the shot instant or moment. Use is largely obsolete. AGI shot off the solid

2892

A method of breaking coal from the solid seam by the use of explosives, when the seam has not previously been cut or sheared to prepare the coal for blasting. Also called shot fast. BCI shot point The point at which a charge of dynamite is exploded for the generation of seismic energy. In field practice, the shot point includes the hole and its immediately surrounding area. See also: shothole shot rock Blasted rock. Nichols, 1 shot runner See: fire runner shot samples Samples taken for assay from molten metal by pouring a portion into water to granulate it. Webster 3rd shot-sawed surface Term used to describe the surface finish of building limestone that is deeply scored by using steel-shot abrasive with gangsaws. AIME, 1 shot soil Soil in which small pellets of iron oxide occur or are forming. AGI shot tamper See: tamper shotter Bedded pebbles and sand; glacial outwash gravels. Arkell shotting The production of shot by pouring molten metal in finely divided streams. Solidified spherical particles are formed during descent and are cooled in a tank of water. ASM, 1 2893

shotty gold Small granular pieces of gold resembling shot. shoulder a. A line formed by the intersection of the face or leading surface of a bit crown and the straight-wall side surface of the crown. Long b. A ledge formed by an abrupt change in the course of a borehole. Long c. A ledge or projection on drill rods, couplings, pipe, or bits formed at points where an increase or decrease in diameter occurs. Long d. The side of a horizontal pipe, at the level of the center line. Nichols, 1 e. A short, rounded spur projecting laterally from the side of a mountain or hill. AGI f. The sloping part of a mountain or hill below the summit. AGI shoulder cutting S. Staff. Cutting the sides of the upper lift of a working place in a thick coal colliery next to the rib, preparatory to breaking the coal. shoulder stone The diamonds set in a bit at or along the line formed by the intersection of the face or leading surface of a bit crown and the straight-walled side surfaces of the bit crown or shank. CF: kerf stone shovel a. Any bucket-equipped machine used for digging and loading earthy or fragmented rock materials. b. There are two types of shovels, the square-point and the round-point. These are available with either long or short handles. The round-point shovel is used for general digging since its forward edge, curved to a point, most readily penetrates moist clays and sands. The square-point shovel is used for shoveling against hard surfaces or for trimming. Carson, 1 c. See: power shovel shovel craneman In bituminous coal mining, a maintenance mechanic who inspects, oils, greases, adjusts, and repairs machinery of a power shovel used to dig and load coal (after blasting) into cars in a strip mine. May be designated according to type of power, as electric-shovel craneman; steam-shovel craneman. Also called stripping-shovel craneman. DOT shovel dozer A tractor equipped with a front-mounted bucket that can be used for pushing, digging, and truckloading. Nichols, 1 2894

shovel front In power-shovel nomenclature, the shovel front is composed of a main boom and a secondary boom known as the dipper stick, at the outer end of which is the dipper or shovel bucket. Carson, 1 shovel loader A loading machine mounted on driven wheels by which it is forced into the loose rock at the tunnel face. A bucket hinged to the chassis scoops up the material, which is elevated over and discharged behind the machine. There are two types: (1) the bucket is discharged directly into a mine car behind the machine, and (2) a short conveyor, built into the loader, receives the dirt from the bucket and conveys it back into a car or conveyor. See also: mechanical shovel; loader; loading shovel. Nelson shovel trough In a duckbill, the shovel part of the loading mechanism that is advanced into a coal pile or retracted according to the adjustment of the operating carrier. Jones, 1 show a. When the flame of a safety lamp becomes elongated or unsteady, owing to the presence of combustible gases in the air, it is said to show. Zern b. The detectable presence of mineral, oil, or gas in a borehole, as determined by examination of the core or cuttings. Long c. Visual particles of gold found in panning a gravel deposit. AGI shower roasting Rapid oxidation-roast of finely ground sulfide ores, which are caused to fall through rising heated air. Pryor, 3 showing a. The first appearance of float, indicating the approach to an outcropping vein or seam. Zern b. Can. Surface occurrence of mineral. Hoffman shrinkage a. The decrease in volume of a soil or fill material through the reduction of voids by mechanical compaction, superimposed loads, or natural consolidation. Nelson b. The settling or reduction in volume of earthen fills, cement slurries, or concrete on setting. Long c. In bitmaking by the powder-metal processes, the difference between the dimensions of the finished bit crown and those of the bit mold. Long d. The decrease in 2895

volume of clayey soil or sediment owing to reduction of void volume, principally by drying. AGI shrinkage cavity A void left in cast metals as a result of solidification shrinkage. ASM, 1 shrinkage crack A crack produced in fine-grained sediment or rock by the loss of contained water during drying or dehydration; e.g., a desiccation crack or a mud crack. AGI shrinkage index The numerical difference between the plastic and shrinkage limits. ASCE shrinkage stope One in which only part of the severed ore is removed during stoping, the balance being temporarily available as support of workings. Used in steeply dipping lodes with strong walls. Pryor, 3 shrinkage stoping A vertical, overhand mining method whereby most of the broken ore remains in the stope to form a working floor for the miners. Another reason for leaving the broken ore in the stope is to provide additional wall support until the stope is completed and ready for drawdown. Stopes are mined upward in horizontal slices. Normally, about 35% of the ore derived from the stope cuts (the swell) can be drawn off ("shrunk") as mining progresses. As a consequence, no revenues can be obtained from the ore remaining in the stope until it is finally extracted and processed for its mineral values. The method is labor intensive and cannot be readily mechanized. It is usually applied to orebodies on narrow veins or orebodies where other methods cannot be used or might be impractical or uneconomical. The method can be easily applied to ore zones as narrow as 4 ft (1.2 m), but can also be successfully used in ore widths up to 100 ft (30 m). Syn: shrinkage with waste fill shrinkage with waste fill See: shrinkage stoping Shropshire method See: longwall 2896

shroud laid rope A rope of four strands laid around a core. Zern shungite A hard black amorphous material containing >98% carbon, interbedded among Precambrian schists; probably the metamorphic equivalent of bitumen, but possibly merely impure graphite. Also spelled schungite. shunt A connection between two wires of a blasting cap that prevents building up of opposed electric potential in them. Nichols, 1 shunt back A track arrangement for bringing a wagon or mine car to another track without the need for a curve, turntable, or traverser. Also called back shunt; switchback. Nelson shutdown time One of the rate provisions in drilling contracts, specifying the compensation to the independent drilling contractor when drilling operations have been suspended at the request of the operator. Williams shute See: chute shutoff valve A device by means of which the flow of gas or fluid can be made to cease--usually not with the intention of metering or regulating the flow. Long shuts Scot. Movable or hinged supports for the cage at a shaft landing. Also called keps; keeps; chairs; dogs; seats. shuttle A back-and-forth motion of a machine that continues to face in one direction. Nichols, 2 shuttle car 2897

A vehicle on rubber tires or continuous treads to transfer raw materials, such as coal and ore, from loading machines in trackless areas of a mine to the main transportation system. See also: rubber-tired haulage; trackless tunneling. Nelson shuttle-car operator In bituminous coal mining, one who drives an electrically powered truck (shuttle car) in a coal mine to transport coal from the excavation point to the conveyor belt. DOT shuttle conveyor a. A conveyor that is moved forward or backward in normal operation to vary the loading or discharge points, or both. It may be designed to move only in a straight path, or in either a straight or a curved path. See also: movable conveyor b. Any conveyor, such as belt, chain, pan, apron, screw, etc., in a self-contained structure movable in a defined path parallel to the flow of the material. shuttle multispectral infrared radiometer See: multispectral scanner sial a. A layer of rocks, underlying all continents, that ranges from granitic at the top to gabbroic at the base. The thickness is variously placed at 30 to 35 km. The name derives from the principal ingredients, silica and alumina. Specific gravity, about 2.7. AGI b. A petrologic name for the upper layer of the Earth's crust, composed of rocks that are rich in silica and alumina; it may be the source of granitic magma. It is characteristic of the upper continental crust. Etymol: an acronym for silica + alumina. Adj: sialic. CF: sialma Syn: sal; granitic layer. AGI siallite a. A group name for the kaolin clay minerals and allophane. AGI b. A rock composed of siallite minerals. AGI sialma A mnemonic term derived from (si) for silica, (al) for alumina, and (ma) for magnesium, applied as a compositional term to a layer within the Earth that occupies a position intermediate between sial and sima. AGI Siam ruby

2898

A name sometimes erroneously applied to the dark ruby spinel occurring with the rubies of Thailand. Siberian aquamarine A blue-green beryl from Siberia, Russia. Siberian ruby Rubellite; a pink variety of elbaite found in Siberia. siberite A violet-red or purple variety of elbaite from Siberia. See also: Siberian ruby Sicilian amber Simetite, a variety of amber. sickening a. A scum that forms on the surface of mercury that retards amalgamating, caused by grease, sulfides, arsenides, etc. Gordon b. The flouring of mercury. See also: floured sicklerite An orthorhombic mineral, Li(Mn,Fe)PO4 forms a series with ferrisicklerite; dark brown. Syn: manganese sicklerite sick mercury Mercury that has become contaminated so that it has neither a clean, bright surface nor a spheroidal shape when in globules. Effect produced by sulfur, oil, talc, graphite, sulfides of antimony, arsenic or bismuth, calcium earths. In this state, it cannot be used to amalgamate gold. Pryor, 3 side a. The more or less vertical face or wall of coal or goaf forming one side of an underground working place. b. The wall of a vein. c. Part of a rock mass bordering on a fault plane. Schieferdecker side adit A side passage sometimes made when the main adit is choked with waste rock. 2899

side arch pups Firebricks of a certain standard size. Osborne side basse A transverse direction of the line of dip in strata. sideboard a. A board used in timbering the sides of a heading. See also: side trees b. A board applied to the sides of conveyors, usually of the chain type, to increase the height when coal is being loaded at the face by hand onto the conveyor. Also applied to a baffle plate used with belt conveyors. Jones, 1 side-boom dredge Similar to the hopper dredge except that the discharge, instead of going into hoppers or directly back into the sea, is carried in a discharge pipe hung from a boom, a distance of from 200 to 500 ft (60 to 150 m) directly to port or starboard of the vessel, and there discharged into the atmosphere, dropping vertically from a height of about 50 ft (15 m) onto the surface of the sea. The drag heads of the dredge provide a channel, and the excavated soil is spread over a wide shoal area on either side, without the necessity of hauling it to the sea. Carson, 2 sidecasting Piling spoil alongside the excavation from which it is taken. Nichols, 2 side-discharge shovel A shovel loader, driven by compressed air or by electricity, for loading loose coal or rock. A bucket of capacity 21 ft3 (0.59 m3 ), hinged to the chassis, digs, lifts, and discharges the material sideways onto a scraper or belt conveyor; suitable for stable holes, pillar methods of working, and general repair work. Nelson side-entrance manhole A deep manhole in which the access shaft is built to one side of the inspection chamber. Hammond side-fired furnace A furnace with fuel supplied from the side. ASTM 2900

sidehill cut A long excavation in a slope that has a bank on one side, and is near original grade on the other. Nichols, 1 side-hitching An act in which a mule is hooked by its harness to the side instead of the front of a loaded car to give it enough momentum to slide onto a cage. Korson side-laning S. Staff. The widening of an abandoned gate road, and making it part of the new side of work. Fay sideline a. The line connecting the dredger with anchorage on either side and winch on board used to steady the hull in required digging position. See also: headline b. A surface line of the claim along the vein. It bounds the side of the claim. sideline agreement In a mineral claim where the apex law applies (United States), neighboring mine owners may come to a sideline agreement to adjust or limit the law as it affects their respective properties. Nelson sidelong reef An overhanging wall of rock in alluvial formation extending parallel with the course of the gutter; generally only on one side of it. side piles The side poling boards used in driving a heading. Stauffer sideplate In timbering, where both a cap and a sill are used, and the posts act as spreaders, the cap and the sill are spoken of as the sideplates. See also: endplate; wallplate. Fay side-port furnace A furnace with ports on the sides. ASTM 2901

siderite a. A trigonal mineral, FeCo3 ; calcite group, with Fe replaced by Mg toward magnesite and Mn toward rhodochrosite; rhombohedral crystals and cleavage; light to dark brown; in bedded deposits (black-band ores, clay ironstone); occurs in hydrothermal veins, cavities in mafic igneous rocks, pegmatites, and limestone; a source of iron. Syn: chalybite; spathic iron; sparry iron; rhombohedral iron ore; iron spar; junckerite; junkerite; siderose; white iron ore. See also: iron ore b. An obsolete syn. of sapphire quartz. See also: sapphire quartz AGI c. An obsolete term formerly applied to various minerals, such as hornblende, pharmacosiderite, and lazulite. AGI d. A general name for iron meteorites, composed almost wholly of iron alloyed with nickel. Obsolete syn: aerosiderite. AGI siderodot A variety of siderite containing calcium. sideroferrite A variety of native iron occurring as grains in petrified wood. siderogel Amorphous FeO(OH) in some bog iron ores. sideromelane A basaltic glass from the palagonite tuffs of Sicily, Italy. Fay sideronatrite An orthorhombic mineral, Na2 Fe(SO4 )2 (OH).3H2 O ; soft; orange to straw-yellow. siderophile a. Said of an element concentrated in the metallic rather than in the silicate and sulfide phases of meteorites, and probably concentrated in the Earth's core relative to the mantle and crust (in Goldschmidt's scheme of element partition in the solid Earth). AGI b. Said of an element with a weak affinity for oxygen and sulfur, and readily soluble in molten iron. Examples are Fe, Ni, Co, P, Pt, Au. CF: lithophile siderophyllite A monoclinic mineral, KFe2 Al(Al2 Si2 )O10 (F,OH)2 ; mica group. 2902

siderosa Sp. Spathic iron ore or siderite. sideroscope An instrument for detecting small quantities of iron by the magnetic needle. Webster 2nd siderose See: siderite siderosis Pneumoconiosis occurring in iron workers from inhalation of particles of iron. Webster 3rd siderosphere See: inner core sidertil A triclinic mineral, FeSO4 .5H2 O ; chalcanthite group; light green. sides A local New York and Pennsylvania term applied by bluestone quarrymen to open joints that extend east and west. side shearing In salt mining, a vertical cut at each end of the room that permits the explosive to expand with the least resistance, thus promoting efficiency and power economy. Kaufmann side shelves The shelves fastened along the sides of the entry throughout the explosion zone on which dust is placed in explosion testing in an experimental mine or gallery. Rice, 2 side shot A reading or measurement from a survey station to locate a point that is off the traverse or that is not intended to be used as a base for the extension of the survey. It is usually made to determine the position of some object that is to be shown on a map. AGI 2903

side slicing See: top slicing combined with ore caving side spit The emission of sparks through the sides of a burning fuse. Fay side stoping See: overhand stoping side thrust a. The lateral force against the borehole walls resulting from the buckling or sag in the drill rods at one or more points above the bit. Long b. The lateral force developed when the area covered by the bit is not uniformly hard. Long sidetracked a. A term applied when tools or downhole drilling equipment is not recovered from a borehole because of the drilling-by or bypassing techniques used. Long b. A term applied when a borehole has been deflected, so as to bypass an obstruction. Long sidetracked hole Drill purposely directed away from a normal, straight course in order to bypass an obstruction or to straighten the hole; or to redirect the deeper portion by redrilling to an alternate bottom-hole location. See also: directional drilling; deviation. AGI sidetracking The deliberate act or process of deflecting and redrilling the lower part of a borehole away from a previous course. AGI side trees a. Posts ranging from 3 to 6 in (7.6 to 15.2 cm) in thickness which support both the head trees and sideboards in a heading. Hammond b. The two posts of a heading set. See also: headtree sidewall core A core or rock sample extracted from the wall of a drill hole, either by shooting a retractable hollow projectile, or by mechanically removing a sample. AGI 2904

sidewall coring tool An eccentric sampling device that gouges a small sample, sometimes in the form of a core, from the sidewall of a borehole. Syn: sidewall sampler Long sidewalls a. Walls, usually masonry, at each end of a culvert. Nichols, 1 b. See: endwall sidewall sampler See: sidewall coring tool sidewall sampling The process of securing samples of formations from the sides of the borehole anywhere in the hole that has not been cased. AGI siding over A short road driven in a pillar in a headwise direction. Zern Siebe-Gorman self-rescuer A self-rescuer consisting of a hermetically sealed, quick-release canister with inhalation and exhalation valves fitted to the top, a head strap, a rubber mouthpiece, a chin rest, and a nose clip. It is carried on a miner's belt and weighs only 22 oz (0.62 kg). The air enters at the perforated diaphragm in the bottom of the canister, and passes through layers of filters before it reaches the mouthpiece. The complete respirator is held in position by a head strap. See also: self-rescuer McAdam, 1 siegburgite A fossil resin from the brown coal near Bonn, Germany; it ranges in color from golden yellow to brownish red, and is partly soluble in alcohol and ether. Fay siege The floor of a pot furnace, often called bench. siegenite An isometric mineral, (Ni,Co)3 S4 ; linnaeite group. Siemens and Halske process 2905

A metallurgical process for the recovery of copper. Copper sulfides are dissolved by solutions of ferric sulfate containing free sulfuric acid, and the solution is then electrolyzed in a tank having a diaphragm. Copper is deposited, and ferric sulfate is regenerated. Liddell Siemens direct process A process for making wrought iron directly from iron ore, without the previous production of pig iron. Standard, 2 Siemens furnace A reverberatory furnace, heated by gas, with the aid of regenerators. Fay siemensite A highly refractory material, produced by the fusion of chromite, bauxite, and magnesite, in an open electric arc furnace. Osborne Siemens-Martin process The production of steel in a reverberatory furnace by oxidation of the impurities by oxides added (either the rust on scrap, mill scale, or pure ores). It may be conducted on either acid or basic lining. See also: open-hearth process Siemens producer A furnace used for the manufacture of producer gas. Fay Siemens-Silesian furnace A Silesian zinc-distillation furnace employing the Siemens system of heat recuperation. Fay sienna a. A brownish orange-yellow clay colored by iron and manganese oxides; used as a pigment. b. See: mineral paint sierra a. A high range of hills or mountains, esp. one having jagged or irregular peaks that when projected against the sky resemble the teeth of a saw; e.g., the Sierra Nevada in California. The term is often used in the plural, and is common in the Southwestern 2906

United States and in Latin America. Syn: serra b. A mountainous region in a sierra. Etymol: Spanish, saw, from Latin serra, saw. AGI Sierra Leone A diamond from the Sierra Leone District in Africa. Long sieve a. A laboratory vessel, the bottom of which is a woven-wire screen, used to separate soil or sedimentary material according to the size of its particles; it is usually made of brass, with the wire-mesh cloth having regularly spaced square holes of uniform diameter. CF: screen AGI b. The screen or grating fixed in a stamp box. c. Vessel, the bottom of which is porous, with apertures of defined size and shape, allowing contents to be retained as oversize or sieved through as undersize. The chief sieve systems used in laboratory work are rings 8 in (20.3 cm) in diameter with woven wire cloths so specified. Pryor, 3 d. This term is generally reserved for testing equipment; the corresponding industrial equipment is generally called a screen. There are several standard series of test sieves; those most frequently met with in the ceramic industry are British standard sieves (conforming with B.S. 410), United States standard sieves (conforming with National Institute of Standards and Technology LC-584 or ASTM-E11), French standard sieves (AFNOR NF 11-501), and German standard sieves (DIN 4188). In Tyler sieves, the ratio between the mesh sizes of successive sieves in the series is 2; thus, the areas of the openings of each sieve are double those of the next finer sieve. Dodd sieve analysis Determination of the particle-size distribution in a soil, sediment, or rock by measuring the percentage of the particles that will pass through standard sieves of various sizes. Syn: sieve classification sieve bend Stationary screen with close-spaced wedge wire bars across wet pulp feed, set around arc of circle. Pryor, 3 sieve classification The separation of powder into particle size ranges by the use of a series of graded sieves. Syn: sieve analysis sieve fraction

2907

In powder metallurgy, that portion of a powder sample that passes through a standard sieve of specified number and is retained by some finer sieve of specified number. ASM, 1 sieve mesh a. Standard opening in sieve or screen, defined by four boundary wires (warp and woof). The laboratory mesh is square and is defined by the shortest distance between two parallel wires as regards aperture (quoted in micrometers or millimeters), and by the number of parallel wires per linear inch as regards mesh. Sixty mesh equals 60 wires/in (152 wires/cm). Pryor, 3 b. The length of the side of a hole in a sieve. See also: mesh Fay sieve scale Term applied to the list of screen apertures, taken in order from the coarsest to the finest. Pit and Quarry sieve shakers Mechanized devices on which a nest of laboratory sieves can be shaken or electrically vibrated during the size analysis of sands. Pryor, 3 sieve sizes Sieves are standardized in British Standard 410 and sieve size diamond powders in British Standard 1987. Osborne sieve texture See: poikiloblastic sieving a. Grading in accordance with particle size and shape by means of sieves or screens. Pryor, 3 b. The operation of shaking loose materials in a sieve so that the finer particles pass through the mesh bottom. By using a number of sieves with different meshes, the particles can be graded according to size. Syn: sifting sifting See: sieving sight 2908

a. A bob or weighted string hung from an established point in the roof of a room or entry, to give direction to the miners driving the entry or room. Fay b. A bearing or angle taken with a compass or transit when making a survey. Fay c. Any established point of a survey. Fay sight distance The distance from which an object at eye level remains visible to an observer. Hammond sighting hub A stake or mark used by a driller as a means of setting and orienting a drill so that the borehole can be drilled to follow a predetermined directional course. Long sight line Established compass or transit course for alignment of working places, usually marked on the roof. BCI sights Bobs or weighted strings hung from two or more established points to give direction to miners driving a chamber or gangway. Hudson sigloite A triclinic mineral, FeAl2 (PO4 )2 (OH)3 .7H2 O ; paravauxite group. sigma heat See: total heat sigma recording methanometer See: butane flame methanometer signal code See: hoist signal code signaling system The arrangement in use for transmitting signals to stop or start conveyors, rope haulages, locomotives, winders, etc. See also: face signaling; loudspeaker face telephone. Nelson 2909

signal system See: mine fan signal system; hoist signal system. significant anomaly An anomaly that is related to ore and that can be used as a guide in exploration. See also: geochemical anomaly silcrete a. A term suggested by Lamplugh (1902) for a conglomerate consisting of surficial sand and gravel cemented into a hard mass by silica. Examples occur in post-Cretaceous strata of the United States. AGI b. A siliceous duricrust. Etymol: "sil"iceous + con"crete." CF: calcrete; ferricrete. AGI silent chain A roller-type chain in which the sprockets are engaged by projections on the link side bars. Nichols, 1 silex a. The French term for flint. AGI b. Silica; esp. quartz, such as a pure or finely ground form for use as a filler. AGI c. An old term formerly applied to a hard, dense rock, such as basalt or compact limestone. Etymol: Latin, hard stone, flint, quartz. The term was used by Pliny for quartz. AGI silexite a. An igneous rock composed essentially of primary quartz (60% to 100%), e.g., a quartz dike, segregation mass, or inclusion inside or outside its parent rock. AGI b. The French term for chert; specif. chert occurring in calcareous beds. See also: chert silica The chemically resistant dioxide of silicon, SiO2 ; occurs naturally as five crystalline polymorphs: trigonal and hexagonal quartz, orthorhombic and hexagonal tridymite, tetragonal and isometric cristobalite, monoclinic coesite, and tetragonal stishovite. Also occurs as cryptocrystalline chalcedony, hydrated opal, the glass lechatelierite, skeletal material in diatoms and other living organisms, and fossil skeletal material in diatomite and other siliceous accumulations. Also occurs with other chemical elements in silicate minerals. silica brick 2910

a. Refractory bricks used to line roofs of furnaces, where there is no contact with basic molten material. Pryor, 3 b. Silica cemented with a binding agent, for example, slurried lime. Pryor, 3 silica-firebrick molder One who forms silica brick for use in lining furnaces and ovens of various kinds. DOT silica refractories Refractories made from quartzite, bonded by lime, and consisting essentially of silica, usually with about 2% of lime, and small quantities of iron oxide, alumina, and alkalies. Henderson silica rock An industrial term for certain sandstones and quartzites that contain at least 95% silica (quartz). It is used as a raw material of glass and other products. CF: silica sand silica sand An industrial term for a sand or an easily disaggregated sandstone that has a very high percentage of silica (quartz). It is a source of silicon and a raw material of glass and other industrial products. CF: silica rock silicate a. A compound whose crystal structure contains SiO4 tetrahedra, either isolaed or joined through one or more of the oxygen atoms to form groups, chains, sheets, or threedimensional structures with metallic elements. Silicates were once classified according to hypothetical oxyacids of silicon (see metasilicate and orthosilicate) but are now calssified according to crystal structure (see nesosilicate, sorosilicate, cyclosilicate, inosilicate, phyllosilicate, tectosilicate). AGI b. A term used in the Joplin district, Missouri, for zinc carbonate. silicate brick Usually refers to Forsterite brick. Strictly, most bricks are silicate bricks of one kind or other. silicate degree In the metallurgical nomenclature of slags, the ratio of the weight of oxygen in the acid to the weight of oxygen in the base. Newton, 1 2911

silicate minerals Minerals with crystal structure containing SiO4 tetrahedron arranged as (1) isolated units, (2) single or double chains, (3) sheets, or (4) three-dimensional networks. Leet, 1 silication The process of converting into or replacing by silicates, esp. in the formation of skarn minerals in carbonate rocks. CF: silicification silicated. AGI silicatization process A special method of sealing off water, for example, reducing its inflow into shafts, by the injection of calcium silicate under pressure. It is sometimes used to reduce the leakage of water through defective lengths of tubbing in a shaft. The calcium silicate is highly impervious on solidification, behind the leaking tubbing. Nelson silicatosis A disease of the lungs thought to be caused by silicates. siliceous a. Of, relating to, or derived from silica; containing or resembling silica or a silicate; silicic. Also spelled silicious. Webster 3rd b. Said of a rock containing free silica or, in the case of volcanic glass, silica in the norm. siliceous dust Dust arising from the crushing or other dry working of sand, sandstone, trap, granite, and other igneous rocks is included in this class. Siliceous dusts are not soluble in body fluids, and when introduced into the respiratory tract in the form of particles of certain sizes and in sufficiently high concentration, they produce nodular growths that often result in a form of pneumonoconiosis that has been known as silicosis or "stone cutters" consumption. Pit and Quarry siliceous earth A general term including both diatomaceous earth (diatomite) and radiolarian earth (radiolarite). siliceous fire clay A fire clay composed mainly of fine white clay mixed with clean, sharp sand, found in pockets. Nelson 2912

siliceous materials Materials that consist mainly of SiO2 and must be low in metallic oxides and alkalies. Newton, 1 siliceous oozes These are pelagic deposits that contain a large percentage of siliceous skeletal materials produced by planktonic plants and animals. The siliceous oozes are subdivided into two types on the basis of the predominance of the forms represented, namely (1) diatom ooze, containing large amounts of diatom frustules, therefore, produced by plankton plants, and (2) radiolarian ooze, containing large porportions of radiolarian skeletons formed by these plankton animals. Hunt siliceous ore Another name for gold-quartz ores. Newton, 1 siliceous rocks Generally, rocks high in silica. siliceous shale A hard, fine-grained rock of shaly structure generally believed to be shale altered by silicification. Syn: phthanite See also: porcellanite siliceous sinter The lightweight porous opaline variety of silica, white or nearly white, deposited as an incrustation by precipitation from the waters of geysers and hot springs. The term has been applied loosely to any deposit made by a geyser or hot spring. Syn: sinter; pearl sinter; geyserite; fiorite. AGI silicic a. In petrology, containing silica in dominant amount. b. In chemistry, containing silicon as the acid-forming element. c. Said of a silica-rich igneous rock or magma. Although there is no firm agreement among petrologists, the amount of silica is usually said to constitute at least 65% or two-thirds of the rock. In addition to the combined silica in feldspars, silicic rocks generally contain free silica in the form of quartz. Granite and rhyolite are typical silicic rocks. The synonymous terms "acid" and "acidic" are used almost as frequently as silicic. Syn: acidic; intermediate; persilicic. CF: basic; ultrabasic. AGI 2913

silicification a. The introduction of, or replacement by, silica, generally resulting in the formation of fine-grained quartz, chalcedony, or opal, which may fill pores and replace existing minerals. CF: silication Syn: silification b. A process of fossilization whereby the original organic components of an organism are replaced by silica, as quartz, chalcedony, or opal. AGI silicified Adj. of silicification. silicified wood A material formed by replacement of wood by silica in such manner that the original form and structure of the wood is preserved. The silica is generally in the form of opal or chalcedony. Syn: petrified wood; woodstone; agatized wood; fossilized wood; opalized wood; shinarump. silicinate Said of the silica cement of a sedimentary rock. AGI silicious ore See: natural ore silicon A nonmetallic element that is the second most abundant on Earth, being exceeded only by oxygen. Symbol, Si. Silicon is not found free in nature, but occurs as the oxide and silicate. Sand, quartz, rock crystal, amethyst, agate, flint, jasper, and opal are some of the forms in which the oxide appears. Hornblende, orthoclase, kaolin, and biotite are a few of the numerous silicate minerals. Used in the electronics and space-age industries; used to make concrete, brick, and glass. Miners often develop a serious lung disease, silicosis, from breathing large quantities of the dust. Handbook of Chemistry and Physics, 3 silicon alloys Silicon bronze is a noncorroding alloy with copper and tin. Silicon copper (70% to 80% copper and 20% to 30% silicon) is an alloy added to molten copper or brass to remove oxygen. Silicon iron is a grain-improved iron, corrosion resistant. See also: ferrosilicon silicon borides 2914

Two compounds have been reported: SiB4 , oxidation resistant to 1,370 degrees C; SiB6 , melting point 1,950 degrees C. A special refractory has been made by reacting silicon and boron in air, the product containing SiB4 and Si in a borosilicate matrix; it is stable in air to at least 1,550 degrees C and has good thermal shock resistance. Syn: boron silicides silicon copper A rich copper alloy added to molten copper in order to secure clean, solid castings free from blowholes, swellings, etc. Crispin silicon dioxide See: silica siliconize To unite or cause to unite with silicon, as in the combination of iron with silicon in certain metallurgical processes. Standard, 2 silicon-oxygen tetrahedron A fundamental structural unit of silicate minerals formed by four oxygen ions surrounding one silicon ion such that lines connecting the four oxygen nuclei show the outline of a geometric tetrahedron. It is commonly written SiO4 with the electronic charge of minus 4 for the unit assumed. See also: silicate silicon spiegel a. A spiegeleisen containing 15% to 20% manganese and 8% to 15% silicon used in making certain special steels. Webster 3rd b. A form of pig iron. Henderson silicon steel A variety of steel containing up to 5% silicon. It is very hard, but is brittle and difficult to work. silicosis a. Lung disease caused chiefly by inhaling rock dust from air drills. Nichols, 1 b. A condition of massive fibrosis of the lungs marked by shortness of breath and resulting from prolonged inhalation of silica dusts by those--such as stonecutters, asbestos workers, miners--regularly exposed to such dusts. See also: pneumoconiosis; simple silicosis; mining disease. Webster 3rd 2915

silicotuberculosis Complication of tuberculosis by silica. Hartman, 1 silification See: silicification silk Microscopically small, needlelike inclusions of rutile crystals in a natural gem, such as ruby, sapphire, or garnet, from which subsurface reflections produce a whitish sheen resembling that of silk fabric. silklay A finely ground-plastic clay of high refractoriness used as a bond for molding sands. Osborne silky luster a. The luster of silk, peculiar to minerals having a fibrous structure. The fibrous form of gypsum and satin spar are good examples of silky luster. Nelson b. A type of mineral luster characteristic of some fibrous minerals, such as chrysotile and gypsum. sill a. Applied in mining to flat-bedded strata of sandstone or similar hard rocks. AGI b. A concordant sheet of igneous rock lying nearly horizontal. A sill may become a dike or vice versa. Nelson c. The floor of a gallery or passage in a mine. Standard, 2 d. Fireclay, used for making slate or sill pencils, Coal Measures. CF: stone sill e. See also: floor sill f. A submarine ridge or rise at a relatively shallow depth, separating a basin from another basin or from an adjacent sea and causing the basin to be partly closed, e.g., in the Straits of Gibraltar. AGI g. A ridge of bedrock or earth material at a shallow depth near the mouth of a fjord, separating the deep water of the fjord from the deep ocean water outside. Syn: threshold h. The upper limit of any variogram model that has such a limit, i.e., that tends to "level off" at large distances. The spherical, gaussian, exponential, and nugget models have sills. For the linear model, "sill/range" is used merely to define the slope. sill depth Greatest depth at which there is free, horizontal communication between two ocean basins. Hy 2916

sillenite An isometric mineral, Bi12 SiO20 ; forms greenish, earthy or waxy masses; at Durango, Mexico. sillimanite a. An orthorhombic mineral, Al2 SiO5 ; trimorphous with kyanite and andalusite; forms long, slender, needlelike crystals commonly in wisplike or fibrous aggregates (fibrolite) in gneisses and schists at granulite grade; also occurs in alluvial deposits. It forms at the highest temperatures and pressures of a regionally metamorphosed sequence and is characteristic of the innermost zone of contact-metamorphosed sediments. CF: mullite; fibrolite. b. Loosely used for the aluminum silicate minerals sillimanite, kyanite, andalusite, dumortierite, topaz, and mullite. c. A high heat-resisting ceramic material containing a maximum amount of mullite, developed from the alteration of andalusite during firing to 1,550 degrees C and used for special porcelain shapes, furnace patches, and refractories. sillimanite schist A schist containing an appreciable amount of sillimanite (fibrolite). Sinkankas sillite Gumbel's name for a rock from the Bavarian Alps, variously referred to by others as gabbro, diabase, mica syenite, and mica diorite. sills Strong timbers laid horizontally to support posts or other tunnel timbers. Stauffer silo A tall tower, usually cylindrical and of reinforced concrete construction, in which grain, cement, coal, or similar bulk material is stored. Hammond silt a. In anthracite terminology, the accumulation of waste fine coal, bone, and slate settled out of breaker water. It is made up of particles ranging in size from 3/32-in (2.4-mm) round-opening to the finest slime. The material is also called sludge, culm, fines, slush, and mud. It is the partly dewatered solids content of what has been defined as slurry. See also: rock flour b. In bituminous coal terminology: Syn: coal sludge c. Material passing the No. 200 U.S. standard sieve that is nonplastic or very slightly plastic and that 2917

exhibits little or no strength when air-dried. ASCE d. Breaker waste composed of water, coal, slate, pyrite, and clay. Korson siltation See: silting silt box A loose iron box fitted in the bottom of a gulley for collecting deposited silt. It can be removed periodically for emptying and flushing. Hammond silt displacement A system of using a shield for driving a tunnel in silts that are nearly fluid. Hammond silting a. The deposition or accumulation of silt that is suspended throughout a body of standing water or in some considerable portion of it; esp. the choking, filling, or covering with stream-deposited silt behind a dam or other place of retarded flow, or in a reservoir. The term often includes sedimentary particles ranging in size from colloidal clay to sand. Syn: siltation b. Sedimentation in water that results in the deposition of somewhat fine material, which is suspended in the entire body of water or in some considerable portion of it. AGI c. Filling with soil or mud deposited by water. See also: hydraulic mine filling silting up The filling, or partial filling, with silt, as of a reservoir that receives fine-grained sediment brought in by streams and surface runoff. The term has been used synonymously with sedimentation without regard to any specific grain size. AGI siltite See: siltstone siltstone An indurated silt having the texture and composition of shale but lacking its fine lamination or fissility; a massive mudstone in which the silt predominates over clay; a nonfissile silt shale. It tends to be flaggy, containing hard, durable, generally thin layers, and often showing various primary current structures. Syn: siltite claystone. AGI silt trap 2918

A settling hole or basin that prevents water-borne soil from entering a pond or drainage system. Nichols, 1 Silurian A period of the Paleozoic, thought to have covered the span of time between 440 and 400 million years ago; also, the corresponding system of rocks. The Silurian follows the Ordovician and precedes the Devonian; in the older literature, it was sometimes considered to include the Ordovician. It is named after the Silures, a Celtic tribe. AGI silver a. A white metallic element that is very ductile and malleable. Symbol, Ag. Occurs native and in ores such as argentite and horn silver; lead, lead-zinc, copper, gold, and copper-nickel ores are its principal sources. Used for jewelry, photography, dental alloys, and coinage. Handbook of Chemistry and Physics, 3 b. An isometric or hexagonal mineral, Ag , native silver; commonly alloyed with Hg or Au; soft; metallic; sp gr, 10.5; in oxidized zones of hydrothermal deposits. silver amalgam a. A solid solution of mercury and silver crystallizing in the cubic system. The percentage of silver is usually about 26%, but in the variety arquerite it reaches 86%. It is of rare occurrence, and is found scattered either in mercury or silver deposits. CMD b. A naturally occurring "amalgam," an isometric mineral, (Ag,Hg); rarely found scattered either in mercury or silver deposits. See also: amalgam silver bonanza A rich silver mine. Mathews silver-copper glance See: stromeyerite silver freighter A wagoner who hauls silver ore. Mathews silver glance The native silver sulfide, argentite. Fay silver halides 2919

Silver bromide, AgBr; silver iodide, AgI; silver chloride, AgCl; and silver fluoride, AgF. The bromide and chloride are sensitive to light and are of basic importance in photography. CMD silvering a. A plating or covering of silver or an imitation of it, as applied to any surface; as, the silvering on the back of a mirror. Standard, 2 b. The art or process of coating surfaces with silver. Standard, 2 silver lead Lead containing silver. Standard, 2 silver lead ore The name given to galena containing silver. When 1% or more of silver is present, it becomes a valuable ore of silver. Syn: argentiferous galena CMD silver minerals Occurs native, alloyed with gold as electrum, as sulfide argentite, Ag2 S , proustite, pyrargyrite, and horn silver, AgCl, or cerargyrite. Main source is argentiferous ores of lead, zinc, and copper where it is extracted as a byproduct. Bulk of production is used for coinage, electrical alloys, photographic chemicals, and the arts. Pryor, 3 silver sand a. A sharp, fine sand of a silvery appearance used for grinding lithographic stones, etc. b. Specially pure silica. Pryor, 3 sima a. The basic outer shell of the Earth; under the continents it underlies the sial, but under the oceans it directly underlies the water. Originally, the sima was considered basaltic in composition with a specific gravity of about 3.0. In recent years, it has been suggested that the sima is peridotitic in composition with a specific gravity of about 3.3. First used in its present form and spelling by Suess. AGI b. A petrologic name for the lower layer of the Earth's crust, composed of rocks that are rich in silica and magnesia. It is equivalent to the oceanic crust and to the lower portion of the continental crust, underlying the sial. Etymol: an acronym for silica + magnesia. Adj: simatic. CF: sial; sialma. Syn: intermediate layer; basaltic layer. AGI Simbal breathing apparatus 2920

An improved liquid oxygen breathing apparatus, weighing 33 lb (15 kg) and approved for use in British mines. Air is fed to the wearer at a temperature of 50 degrees F (10 degrees C) rising to 70 degrees F (21.1 degrees C) in just over 1/2 h and is still only 80 degrees F (26.7 degrees C) after 2-1/2 h. Nelson simetite A deep-red to light orange-yellow variety of amber having a high content of sulfur and oxygen and a low content of succinic acid; occurs in the waters off Sicily. similar fold A fold in which the orthogonal thickness of the folded strata is greater in the hinge than in the limbs, but the distance between any two folded surfaces is constant when measured parallel to the axial surface. Thus, if the shape of one bed is that of a sine curve, all the beds show the same shape. Similar folds show thinning on the limbs and thickening at the axes. CF: parallel fold; supratenuous fold. Syn: concentric fold AGI similor A golden-colored variety of brass. Also called Mannheim gold; Prince Rupert's metal. simonyite See: bloedite simple beam A simply supported beam. Hammond simple bending The bending of a beam that is freely supported, having no fixed end. Hammond simple explosives These explosives consist of one simple chemical compound. The explosive heat is liberated with the breaking down of the molecules and the atoms recombining to form water, carbon dioxide, nitrogen and other gases, and possibly solid substances such as carbon. To this group belong explosives in the proper sense of the word, such as nitroglycerin, nitroglycol, nitrocellulose, trotyl, and cyclonite (RDX). Also includes "molecular explosives." Fraenkel simple kriging 2921

A variety of kriging that assumes that local means are relatively constant and equal to the population mean, which is well known. The population mean is used as a factor in each local estimate along with the samples in the local neighborhood. This is not usually the most appropriate method for environmental situations. simple mineral A mineral found in nature, as distinguished from rocks, which, in the scientific sense, are mixtures of minerals. Calcite and hematite are simple minerals, while granite is a mixture of three simple minerals--quartz, feldspar, and mica. Standard, 2; Fay simple ore Ore that yields a single metal. CF: complex ore simple pneumoconiosis Pneumoconiosis of the lungs that can be related to the amount (and possibly the nature) of the dust breathed by miners over the years. See also: complicated pneumoconiosis simple silicosis Silicosis that is not complicated by tuberculosis; a condition that may remain almost stationary for many years. See also: mining disease Nelson simple split seam A coal seam that has separated into two layers of coal some distance apart vertically. See also: multiple splitting Simplex pump A reciprocating single- or double-action piston pump having one water cylinder. Long simplotite A monoclinic mineral, CaV4 O9 .5H2 O ; dark green. simpsonite A trigonal mineral, Al4 (Ta,Nb)3 (O,OH,F)14 ; yellow-brown. Simpson's rule

2922

A rule for estimating the area of an irregular figure after dividing it into an even number of parallel strips of equal width. See also: trapezoidal rule simulated insert bit A core bit in the face of which are deeply cut, closely spaced waterways to produce the superficial appearance of an insert-type bit. Also called Thedford crown bit. Long simulated workplace protection factor A surrogate measure of the workplace protection provided by a respirator. NIOSH simultaneous filling Filling in which the mined-out area or room is filled immediately after mining out only a small part of the deposit. Stoces simultaneous shot firing The concurrent firing of a round of shots using instantaneous detonators. BS, 12 sincosite A tetragonal mineral, Ca(VO)2 (PO4 )2 .5H2 O ; a vanadium analog of the meta-autunite group; green; a source of vanadium. sing A hissing noise often made by gas and water when a seam of coal is cut into. Fay singing a. Resonance phenomenon that is frequently observed on marine seismograms. Schieferdecker b. A seismic resonance phenomenon that is produced by short-path multiples in a water layer. Syn: reverberation; ringing. AGI single-acting ram See: one-way ram single-action pump A pump valved so as to discharge liquid at only one end of the water cylinder. CF: double-action pump 2923

single-approach pit bottom A pit-bottom layout at a mine where development branches off on one side only. The empty cars are returned from the opposite side by a loop, shunt back, turntable, or traverse. See also: loop-type pit bottom Nelson single-bench quarrying Quarrying a rock ledge as a single bench the full height of the quarry face. single block A block with one pulley or sheave. Long single consignment A quantity of coal that is to be sampled to a specified accuracy. It is used in contradistinction to the sampling of a coal received regularly at a given point. See also: isolated consignment single-core shot-firing cable See: shot-firing cable single crystal A crystal, usually grown artificially, in which all parts have the same crystallographic orientation. McGraw-Hill, 1 single-cut sprocket For double-pitch roller chains, a sprocket having one set of effective teeth. Jackson, 1 single-deck screen A screen having one screening surface, not necessarily limited to one size or shape of aperture. BS, 5 single entry A system of opening a mine by driving a single entry only, in place of a pair of entries. The air current returns along the face of the rooms, which must be kept open. single-entry room-and-pillar mining 2924

See: room-and-pillar single-entry zone test A test in which coal dust is placed only in a single entry. Rice, 2 single-grained structure An arrangement composed of individual soil particles; characteristic structure of coarsegrained soils. See also: soil structure; flocculent structure; honeycomb structure. ASCE single-hand drilling Rock drilling by hand; e.g., in narrow reefs. A drill steel held in the left hand is struck blows with a 4-lb (1.8-kg) hammer, the drill being turned between the blows. The drilling is very slow and laborious. Nelson single-inlet fan A centrifugal fan in which air enters the impeller at one side only. BS, 8 single-intake fan A ventilating fan that takes or receives its air from one side only. single jack a. A lightweight hammer, usually 4 lb (1.8 kg) or less. When used in hand drilling holes in rock, the hammer is held in one hand and the drill is held in the other. Long b. Sometimes incorrectly used to designate a sinker drill. Long c. A drill column having a single jackscrew in the bottom end. See also: drill column single-layer bit See: surface-set bit single opening Any underground opening separated from a free surface by a distance greater than three times the size of the opening in the direction of the free face. single outlet For safety reasons, mines with only a single outlet (shaft) are subjected to restrictions in the numbers of mine workers employed at a time. Beerman 2925

single packing The conventional method of strip packing on a longwall face, in which the widest pack is along the roadside. A single packing system varies but may have a 10-yd (9.1-m) roadside pack, then 7 yd (6.4 m) of waste, followed by 4-yd (3.7-m) packs and 5 yd (4.6 m) of waste repeated across the entire face. See also: double packing; strip packing. Nelson single-phase circuit A two-wire circuit using alternating current. Kentucky single-pulley-drive conveyor A conveyor in which power is transmitted to the belt by one pulley only. NEMA, 2 single refraction Light refraction in an isotropic crystal or amorphous substance according to Snell's law, as opposed to the birefringence of an anisotropic crystal. single-road stall S. Wales. A system of working coal by narrow stalls. Fay single-roll breaker A coal-crushing machine in which the roll teeth crack downward on the lump and the roll itself compresses the coal against the breaker plates. Teeth of two or more designs are used generally on the same roll, some for the slugging, cracking, or blow action and others for a pulling and splitting force. The breakers are not easy to stall by choking, since they will pass a heavy overload, partly because of the action of a relief mechanism, with which they are all equipped. Mitchell single-roll crusher A crushing machine consisting of a rotating cylinder with a corrugated or toothed outer surface that crushes material by pinching it between the teeth and stationary breaking bars. CF: double-roll crusher ACSG, 2 single-rope friction pulley See: Koepe sheave single-rope haulage 2926

A system of underground haulage in which a single rope is used, the empty trip running in by gravity. Engine-plane haulage. single-round nose The cross-sectional view of the cutting-face portion of a core bit when the profile is an arc having a radius equal to or greater than the wall thickness. See also: profile single-round-nose bit See: single-round nose single-row blasting The drilling, charging, and firing of a single row of vertical holes along a quarry or opencast face. The holes may be fired simultaneously or by delay detonators to give a peeling action starting at one end of the face. See also: multiple-row blasting single shot A charge in one drill hole only fired at one time, as contrasted with a multiple shot where charges in a number of holes are fired at one time. single-shot blasting unit A single-shot blasting unit is a unit designed for firing only one explosive charge at a time. Syn: blasting unit single-shot exploders Exploders of the magneto type that are operated by the twist action given by a half-turn of the firing key. A magneto exploder consists essentially of a small armature that can be rotated between the poles of a set of permanent magnets. The armature is rotated by means of toothed gear wheels actuated by the movement of the firing key. The electric circuit between the exploder and the detonator is completed by means of an automatic internal switch operating at the end of the stroke, or contact may be made by means of a pushbutton. McAdam, 2 single-shot instrument A borehole surveying instrument that records only one measurement of the bearing and of the inclination of a hole on a single trip into the borehole. Long single-shot survey 2927

A borehole survey made with a single-shot instrument. Long single sling A sling that has a single hook at one end and an iron or steel ring at the other. See also: two-leg sling single-speed floating control system In flotation, floating control in which the manipulated variable changes at a fixed rate, increasing or decreasing depending on the sign of the actuating signal. Fuerstenau single-spot method One of three recognized methods of determining the average velocity of airflow along a mine roadway by anemometer. A velocity reading is taken at the center of the airway and the result is multiplied by the center constant, whose value ranges between 0.8 and 0.9, to give the average velocity of flow. Alternatively, the reading is taken along a midway line at a position some one-seventh to one-third of the width of the airway, measured from the side. At this position, the mean velocity is obtained, so that no adjustment is required. CF: division method; traversing method. Roberts, 1 single-stage pump A centrifugal pump with a lift of 100 ft (30.5 m) per stage. Hammond single-stall working See: room-and-pillar single stamp mill a. A mill possessing batteries of one stamp each, like the Nissen, instead of the usual five. b. A mill possessing only one stamp, after the Lake Superior fashion, where one big stamp does the work of 150 ordinary gravity stamps. Fay single-toggle jaw crusher A jaw crusher with one jaw fixed, the other jaw oscillating through an eccentric mounted near its top. This type of jaw crusher has a relatively high output, and the product is of fairly uniform size. Dodd single-unit panel

2928

A longwall conveyor face from about 80 to 200 yd (73 to 183 m) long developed between two gate roads, one serving as an intake airway and usually for coal haulage, while the other acts as a return airway and for bringing in supplies to the face. See also: double-unit conveyor Nelson single vein A single ore deposit of identical origin, age and character throughout. A single small vein is weighed and measured by the same law and entitled to the same consideration as the mother lode, and very often is far more valuable in the eyes of the miner. Ricketts singulosilicate A slag with a silicate degree of 1. Newton, 1; Newton, 2 sinhalite An orthorhombic mineral, MgAlBO4 ; structurally analogous to olivines; yellow. sinistral fault See: left-lateral fault sink a. To excavate or drive a shaft or slope. b. The depression in a shaft made by a center blast. Standard, 2 c. A water lodgment. See also: sump d. To put standpipe or casing down through overburden by rotation or by driving, chopping, or washing-- these methods being employed singly or in combination. Long e. To drill or put down a borehole. Long f. A depression in the land surface, esp. one having a central playa or saline lake with no outlet; a hollow in a limestone region communicating with a cavern or subterranean passage so that waters running into it disappear. Also called sinkhole; swallow hole. Webster 3rd g. Lanc. Natural cavity found in iron mines. sinker a. A rock drill for drilling blasting holes in a sinking shaft. Nelson b. A special movable pump used in shaft sinking. c. See: sinker bar d. A person who sinks mine shafts and puts in supporting timber or concrete. Webster 3rd sinker bar a. A heavy rod used to increase the snatching effect of the sliding jars in rope drilling. BS, 9 b. A short bar or stem placed above the drill jars to give force to the upward jar in well drilling with cable tools. Webster 3rd 2929

sinker drill a. A one-person drill that can be held in the hand but is frequently mounted. This drill has found wide application in sinking shafts and is made in several sizes, each suited for a particular kind of work. Also called plugger drill. Lewis b. A rock drill of the jackhammer type commonly used in shaft sinkings. Also called sinker. Webster 3rd c. A hand-held compressed-air rock drill used in boring down holes such as in shaft sinking. Pryor, 3 sink-float processes Processes that separate particles of different sizes or composition on the basis of specific gravity. When ore or coal particles are introduced into a liquid (or into a medium: a solid suspension), those having a specific gravity higher than that of the liquid will sink, while those that are lighter than the liquid will float. Chem. Eng. sink-float separation See: dense-media separation sinkhole A circular depression in a karst area. Its drainage is subterranean, its size is measured in meters or tens of meters, and it is commonly funnel shaped. Syn: doline; sink; leach hole. Partial syn: collapse sink. AGI sinking a. The process by which a shaft is driven. BCI b. Extending excavations downward at or near the vertical plane. See also: raising; shaft sinking. Nelson sinking fire A forge in which wrought-iron scrap or refined pig iron is partly melted or welded together by means of a charcoal fire and a blast. sinking head See: deadhead sinking in rock Shaft sinking in rock usually comprises the following cycle: drilling a round of holes, blasting, removing the broken rock, trimming the shaft to form, placing the sets or concrete in position, and then preparing to drill the next round. Lewis 2930

sinking kibble A large bucket for raising the stones, etc., from a shaft being sunk. Sometimes called bowk; hoppett. Peel sinking lift A lift (pump) of small size with esp. heavy castings to resist the force of blasting; used in shaft sinking. A sinking pump, which is also sometimes called a sinker. Standard, 2; Fay sinking plant In a shaft, a sinking plant consists of the headframe, hoisting equipment, air-compressor for drills, concrete-mixing equipment, and suitable pumps. It may be temporary or permanent. Lewis sinking platform A scaffold or staging designed for use during shaft sinking, particularly during lining operations. Nelson sinking pump A long, narrow pump designed for keeping a shaft dry during sinking operations. It is usually large enough to deal with 1,000 gal/min (3,780 L/min) from the greatest depth at which water will be encountered. A sinking pump must be slung from the surface and be fairly easy to raise and lower when shot firing takes place at the shaft bottom. Most are of the electrically driven centrifugal type and allow for additional stages to be fitted as the shaft depth increases. It may be suspended by a single-drum, worm-driven, capstan engine with a very slow speed. See also: borehole pump; water barrel. Nelson sinks Fractions with a defined upper limit of specific gravity and so described, e.g., sinks 1.60 specific gravity. BS, 5 sinople A red or brownish-red variety of quartz containing inclusions of hematite. Also spelled sinopal; sinopel. sinter a. A chemical sedimentary rock deposited as a hard incrustation on rocks or on the ground by precipitation from hot or cold mineral waters of springs, lakes, or streams; 2931

specif. siliceous sinter and calcareous sinter (travertine). The term is indefinite and should be modified by the proper compositional adj., although when used alone it usually signifies siliceous sinter. Etymol: German sinter, cinder. CF: tufa b. A ceramic material or mixture fired to less than complete fusion, resulting in a coherent mass when cooled. c. A process for agglomerating ore concentrate in which partial reduction of minerals may take place and some impurities be expelled prior to subsequent smelting and refining. d. To heat a mass of fine particles for a prolonged time below the melting point, usually to cause agglomeration. ASM, 1 e. A process commonly used in making diamond bits, whereby powdered metal is compacted in a diamond-set mold or die, and the temperature is raised to a point just below melting, thus fusing the entire mass together. Also called sintered. Long sinter bit A bit, the crown of which is formed by applying heat and pressure to a mixture of powdered metals covering diamonds set inside a mold or die-shaped to the form of a bit crown. The bit crown thus formed may be a surface-set, multilayer, or impregnated type. Long sinter cap A zone of sinter typically positioned at the top of epithermal systems. sintered carbide Sintering as used in powder metallurgy consists of mixing metal carbide powders having different melting points, and then heating the mixture to a temperature approximating the lowest melting point of any metal included. In sintered carbides, powdered cobalt, having the lowest melting point, acts as the binder, holding together the unmelted particles of the hard carbides. See also: cemented carbide sintered carbide-tipped pick The pick generally used in coal cutters and cutter loaders, in which the sintered tip is brazed in various ways to the shank of the pick. In the external-tip type, which is widely used, the sintered tip is brazed externally to the shank, which is usually a forging. It is self-gaging and as the tip wears down, the cutting edge maintains its shape and clearance. In the slotted type, the tip is brazed into a slot cut in the shank of the pick. In the inserted-rod type, the sintered carbide takes the form of a rod inserted into a hollow in the shank of the pick, which is a forging. These picks are widely used in the soft coal mines in Germany. See also: tungsten carbide bit; coal-cutter pick. Syn: inserted rodtype pick sintered matrix 2932

A bit-crown diamond-embedment metal or alloy produced by a sinter powder-metal process. See also: sinter; sinter bit. Long sintered-metal bit See: sinter bit sintering A heat treatment for agglomerating small particles to form larger particles, cakes, or masses; in case of ores and concentrates, it is accomplished by fusion of certain constituents. CTD sinter plant A plant in which sintering is carried out. Nelson sinter set See: sinter bit sinter-set bit See: sinter bit sinuous flow See: turbulent flow Sioux Falls jasper A decorative brown jasperlike, fine-grained quartz, from Sioux Falls, SD. Used for tables and interior architectural trim. siphon An arrangement of closed pipes and valves to conduct water from one level to a lower level over an intervening ridge. The difference of level between the inlet and outlet ends of the pipe column must be sufficient to provide a head great enough to overcome the frictional resistance of the pipe column. The siphon was often used in the earlier days of mining when pumps were too costly or power was not available. See also: suction head; inverted siphon. Nelson siphonage 2933

The action or operation of a siphon. Fay siphon separator An apparatus for the sizing of pulverized ores in an upward current of water. Fay siphon tap See: Arents tap sipylite See: typrite Sirocco fan A centrifugal fan, invented by Samuel Davidson in 1898, with 64 narrow blades curved forward, mounted at the periphery of a braced, open drum. It is a high-speed, smalldiameter fan, usually direct driven. It was a popular fan in Great Britain for many years. See also: Waddle fan Nelson siserskite Former name for iridosmine. sismondine Former name for Mg-rich chloritoid. site exploration a. The investigation and testing of the surface, subsoil, and any obstruction at a site to obtain the full information necessary for designing a complete structure with its foundations. Hammond b. See: site investigation site investigation The collection of basic facts about, and the testing of, surface and subsurface materials (physical properties, distribution, and geologic structure) at a site, for the purpose of preparing suitable designs for a mine, an engineering structure, or other use. AGI site rivet A rivet driven on a construction site. See also: shop rivet Hammond 2934

size To separate minerals according to various screen meshes. size analysis See: particle-size analysis size consist Screen analysis of particle size (coal). Bennett size distribution a. See: particle-size distribution b. Analysis of crushed or ground materials on the basis of particle size. Bennett c. In sizing analysis of sands, the percentage of the sample retained on each laboratory sieve in the range examined. Pryor, 3 size-distribution curve A graphical representation of the size analysis of a mixture of particles of various sizes, using an ordinary, logarithmic, or other scale. BS, 5 sized variation The variation in dimensions of any ceramic product from the intended dimensions. size fraction Portion of a sample of sand lying between two size limits, the upper being the limiting and the lower the retaining mesh. Pryor, 3 size-frequency distribution See: particle-size distribution size range That between upper (limiting) and lower (retaining) mesh sizes with reference to screened or classified material. Pryor, 4 size reduction The breaking of large coal, ore, or stone by primary breaker, or the breaking of smaller sizes by grinding. See also: reduction ratio; primary breaker. Nelson 2935

size selector A device attached to the intake of a dust-sampling instrument to remove the bulk of the particles above 5 to 10 mu m in size; thus the resulting sample is more representative of the health-hazard size range of dust-- mainly 5 mu m and smaller. See also: dust sampling sizing a. The arrangement, grading, or classification of particles according to size; e.g., the separation of mineral grains of a sediment into groups each of which has a certain range of size or maximum diameter, such as by sieving or screening. AGI b. See: screening sizing punch A punch used for pressing of the sintered compact during the sizing operation. Osborne sizing screen A screen or set of screens normally used for dividing a product (for example, washed coal) into a range of sizes. Also called grading screen and classifying screen (undesirable usage). BS, 5 sjoegrenite a. A hexagonal mineral, Mg6 Fe2 (CO3 )(OH)16 .4H2 O ; manasseite group; dimorphous with pyroaurite of the hydrotalcite group. b. The name was formerly used for the phosphates dufrenite and chalcosiderite. S-joint See: longitudinal joint S.J. table A pneumatic table of American design, for the drycleaning of coal. A sizing ratio of 2:1 is desirably the maximum range of sizes that the table can separate in one operation. See also: Kirkup table skares See: scares skarn 2936

An old Swedish mining term for silicate gangue (amphibole, pyroxene, garnet, etc.) of certain iron ore and sulfide deposits of Archean age, particularly those that have replaced limestone and dolomite. Its meaning has been generally expanded to include limebearing silicates, of any geologic age, derived from nearly pure limestone and dolomite with the introduction of large amounts of Si, Al, Fe, and Mg. In American usage, the term is more or less synonymous with tactite. See also: calc-silicate hornfels skate-wheel conveyor A type of wheel conveyor making use of a series of skate wheels mounted on common shafts or axles or mounted on parallel spaced bars on individual axles. skeletal crystal Crystals that develop under conditions of rapid growth and high degrees of supersaturation so that atoms or ions are added more rapidly to edges and corners of growing crystals, resulting in branched "dendrites" or hollow stepped depressions, "hoppers." Ice on windowpanes (frost) and pyrolusite on agate (moss agate) are dendrites; halite and gold may form hopper crystals. CF: dendrite; hopper crystal. skeleton crystals Hollow or imperfectly developed crystals formed by rapid crystallization. Fay skeleton sheathing Consists of a continuous wood frame with sheathing planks placed vertically at intervals, usually of about 4 ft (1.2 m), behind it. Used where the banks consist of compacted, stable soils, primarily to prevent initial yield at the top. CF: close sheathing; tight sheathing. Carson, 1 skeleton tubbing A temporary method of supporting a circular shaft sinking. It consists essentially of iron curbs or rings. Each ring consists of segments of wrought iron, 3 to 5 in (7.62 to 12.7 cm) deep, 5/8 to 7/8 in (1.59 to 2.22 cm) thick, and from 6 to 8 ft (1.82 to 2.44 m) in length. The segments are bent to the curvature of the shaft and bolted together, each ring being suspended from the ring above. Laggings or backing deals are wedged behind the rings. Every fourth ring or so is supported on steel strata bolts driven into holes drilled in the rock sides. See also: temporary shaft support skelp

2937

Mild steel strip, often of Bessemer steel, from which tubes are made by drawing it through a welding bell, at welding temperature, to produce butt-welded or lap-welded tubes or pipes. See also: butt weld Hammond skelp iron Wrought iron rolled into flat bars suitable for making pipe. Mersereau, 2 skerry a. An old English term meaning, variously, thin layers of micaceous sandstone in the Coal Measures, a thin ferruginous sandstone crowded with fossils, or a hard gritty clay used in making firebricks. b. Eng. Thin layers of sandstone in the Keuper Marls, Leicestershire, and Derbyshire coalfield. Arkell c. Micaceous sandstones in the Coal Measures of Wales and the Midlands. Arkell d. Eng. A thin band of ferruginous, micaceous rock, crowded with fossils, Middle Lias, Sutton Basset, Rutland. Arkell skerrystone Mid. Hard, thin-bedded sandstone. skew a. An irregular discontinuous vein striking out from the principal vein in an uncertain direction, lying in a slanting and irregular position. b. The angled support from which an arch is sprung. AISI skewed On a horizontal angle, or in an oblique course or direction. Nichols, 1 skewed roller conveyor A roller conveyor having a series of rolls skewed to direct objects laterally while being conveyed. skewness In coal sampling, a lack of symmetry in the particle-size distribution. It is a tendency of the observed data to extend farther to one side of the average than to the other. Mitchell skew plate See: bloomery 2938

skews a. Stones cut to form the coping of a gable. Arkell b. Cracks on irregular joints in a mine, sometimes indicating danger from falls. Arkell skiagite A hypothetical garnet "molecule," Fe3 Fe2 (SiO4 )3 . skialith A vague remnant of country rock in granite, obscured by the process of granitization. CF: schlieren; xenolith. AGI skid a. An iron shoe or clog attached to a chain and placed under a wheel to prevent its turning when descending a steep hill; a drag. Webster 3rd b. An arrangement upon which certain coal-cutting machines travel along a working face. Fay c. A metal slide placed under a mine car wheel temporarily to restrict the speed of a trip on a descending grade. BCI d. A metal plate placed under a shortwall cutting machine to control it while cutting. BCI e. The sledlike platform forming the base on which a machine or structure is set and slid or skidded into position; also, the sled runner, bottom-most part of the base of a drill or other machine. Long skid-mounted A term applied when a drill or other machine is attached permanently to a skid. Long ski-lift conveyor A method of transporting miners to the coal face in special chairs that move continuously on an endless conveyor. Nelson skim gate A gating arrangement designed to prevent the passage of slag and other undesirable materials into a casting. ASM, 1 skimmer a. A single-bucket excavator in which the bucket travels along the boom, which is kept almost horizontal during operation. Dodd b. An excavator base machine equipped with jib and bucket for digging and loading from a shallow face above track level. Nelson 2939

skimmer equipment A digging bucket mounted to slide along the boom of an excavator so that the bucket can be used to trim various angles of slope from the horizontal to about 60 degrees elevation. Hammond skimming The removal of the top layer of soil or of irregularities in the ground surface at new mine or opencast sites. See also: skimping Nelson skimming gate A channel in a sand mold having over it a bridge that removes the dross from the molten metal as it passes through. See also: skimmer Standard, 2 skimming ladle Any ladle used in skimming; specif., a ladle used for pouring molten metal, having its lip covered with a guard to retain the dross. Standard, 2 skimping a. The skimmings of the dross from the ore in the vat or tank. Nelson b. See: jigging skin effect a. Tendency of an alternating current to concentrate at the surface of a conductor. Schieferdecker b. The frequency-dependent reduction of resistivity log measurements in conductive formations due to inductive interaction between the current paths; the induction logs now operating at about 20 kHz are most affected. AGI c. The reduction of formation permeability in the vicinity of a well bore caused by drilling and completion operations. AGI d. The concentration of alternating current in a conductor towards its exterior boundary. AGI skin flotation a. A concentration process in which adhesion is effected between a free water surface and particles, usually larger than those involved in froth flotation. Gaudin, 1 b. In skin flotation processes, the separation between minerals and gangue is accomplished at the surface of a body of water, or, in other words, at the air-water interface. Use is made of the surface tension of the water and of the fact that certain minerals, such as sulfides and hydrocarbons, resist being wetted by water. See also: flotation skin friction 2940

a. Friction between a fluid and the surface of a solid moving through it, or between a moving fluid and its enclosing surface. Webster 3rd b. The frictional resistance developed between soil and a structure. ASCE c. Resistance of ground to the movement of a pile or caisson, generally proportional to the area in contact. Hammond d. See: wall friction skin rock The thin band of rock immediately surrounding an excavation. Spalding skip a. A guided steel hoppit, usually rectangular, with a capacity up to 50 st (45.4 t), which is used in vertical or inclined shafts for hoisting coal or minerals. It can also be adapted for personnel riding. The skip is mounted within a carrying framework, having an aperture at the upper end to permit loading, and a hinged or sliding door at the lower end to permit discharge of the load. The cars at the pit bottom deliver their load either directly into two measuring chutes located at the side of the shaft or into a storage bunker from which the material is fed to the measuring chutes. Nelson b. A large hoisting bucket, constructed of boiler plate that slides between guides in a shaft, the bail usually connecting at or near the bottom of the bucket so that it may be automatically dumped at the surface. c. An open iron vehicle or car on four wheels, running on rails and used esp. on inclines or in inclined shafts. Sometimes spelled skep. d. A thin slice taken off a breast, pillar, or rib along its entire length or part of its length. Also called slab. e. A truck used in a mine. Gordon f. A small car that conveys the charge to the top of a blast furnace. Mersereau, 2 skip bucket The tub or bucket used for containing the material conveyed by a skip hoist. skip haulage A method of underground haulage sometimes adopted in steep workings, where the gradient is 1:2 to 1:1.5. There are two kinds: (1) a skip carriage on which the tub is placed in a horizontal position; and (2) a self-dumping system in which the skip, which is permanently attached to the rope, is discharged automatically at the top of the incline and then returned for reloading. Nelson skip hoist A bucket or car operating up and down a defined path, receiving, elevating, and discharging bulk materials. skip loader I 2941

In metal mining, one who loads ore into a skip (large can-shaped container) from skip pockets (underground storage bins) at different shaft stations in a mine, operating a mechanical device to open and close the gates of the loading chutes. Also called skipman; skipper. DOT skip miner In bituminous coal mining, one who drills holes into pillars of coal supporting the roof, charges holes with explosives, and blasts out slabs (skips) of coal to widen haulageway or working place. DOT skip operator In the iron and steel industry, one who controls the skip hoist by which a skip car containing coke, limestone, or ore is hauled up an inclined runway to the furnace top and dumped into the charging bell of the furnace. DOT skipping The working of 2 to 10 yd (1.8 to 9.1 m) of coal along the side or sides of a narrow stall or heading to gain coal and make room for ripping stone. See also: rib-side pack skipping the pillar a. To take a slice off a pillar before abandoning the workings; to rob. Fay b. Widening a gangway or entry. Fay skip shaft A mine shaft esp. prepared for hauling a skip. Standard, 2 skip system A system used for moving material from a quarry floor to a plant located at a considerable elevation. This system utilizes two parallel inclined tracks with a skip car operating on each track. The cars are operated by cables controlled by a winding gear at the head of the incline. The quarry trucks or cars deliver their loads to the skips through a chute at the base of the incline. A hopper at the top of the incline receives the loads from the skips and feeds the rock to a crusher. Pit and Quarry skirt A vertical strip placed at the side of a conveyor belt to prevent spillage or to increase capacity. Nichols, 1 2942

skirting In pillar extraction, it refers to a stall or roadway working a slice or lift of coal along the side of a pillar. Nelson skirt plates Steel sideplates that overlap a conveyor belt slightly and assist in settling the coal on the belt at the tail end or at a transfer point. Nelson skirts That which bounds and limits a vein's breadth, Derbyshire, U.K. skirt-type core spring A core lifter, usually a split-ring type, having a split, thin tubular extension attached above the beveled portion of the core spring, which slides upward and inside the lower end of the inner tube of a core barrel. Long skleropelite A rock produced by low-grade metamorphism of an argillaceous sediment without the development of cleavage. See also: hornfels sklodowskite A monoclinic mineral, (H3 O)2 Mg(UO2 )2 (SiO4 )2 .2H2 O ; structurally similar to uranophane and cuprosklodowskite; strongly radioactive; citron-yellow. Also spelled sklodovskite. skrin Derb. Cross fissures in limestone, sometimes containing small quantities of ore. Also called scrin. skull cracker A heavy iron ball allowed to drop from a height to break up, or crack, hard substances, as aloxite, rock, etc. Mersereau, 2 skull drop A place where heavy ladle skulls are broken. Fay 2943

skulls See: sculls skutterudite An isometric mineral, CoAs2-3 , having Co replaced by Ni toward nickel-skutterudite; metallic; tin white to silver gray showing iridescent tarnish; a minor source of cobalt. Syn: cobalt skutterudite slab a. A piece of metal, intermediate between ingot and plate, with the width at least twice the thickness. ASM, 1 b. Cleaved or finely parallel jointed rocks, which split into tabular plates from 1 to 4 in (2.54 to 10.16 cm) thick. Slabs are seldom as strong as flags. Syn: slabstone slabbing a. Close timbering between sets of timber. b. Lagging placed over bars. Also called slabs. c. Cutting a slice or slab from the side of a pillar. slabbing cut A drill hole pattern suitable for a wide rectangular tunnel; e.g, 8 ft by 15 ft (2.4 m by 4.6 m) wide. The entire face is fired in three separate rounds of shots, the first or cut holes providing a free face for the remaining shots. The face is broken in successive lifts or slabs from one side to the other. Also called swing cut. Nelson slabbing machine a. A power-driven, mobile cutting machine, which is a single-purpose cutter in that it cuts only a horizontal kerf at variable heights. Syn: arcwall machine b. A coal-cutting machine designed to make cuts in the side of a room or entry pillar preparatory to skipping or slabbing the pillar. Jones, 1 slabbing method A method of mining pillars in which successive slabs are cut from one side or rib of a pillar after a room is finished, until as much of the pillar is removed as can safely be recovered. This system has the disadvantage that the open area is always increasing and the loaders are working away from the solid pillars toward the goaf. Lewis slab entry 2944

An entry widened or slabbed to provide a working place for a second miner. slabstone A rock that readily splits into slabs; flagstone. See also: slab AGI slack a. Fine-grained coaly material resulting from weathering, screening, or washing of coal. b. To disintegrate rapidly when exposed to weathering. AGI c. Commonly used to describe the smaller sizes of coal passing through screen openings, approx. 1 in (25.4 mm) or less in diameter. Mitchell d. The process by which soft coal disintegrates when exposed to the air and weather; also to slake, as lime. e. Small coal, usually less than 1/8 in (3.2 mm). It has a high ash content and is difficult to clean in the washery. High-ash slack is being used increasingly in special boilers and power stations. See also: culm; duff. Nelson slack adjuster In air brakes, the connection between the brake chamber and the brake cam. Nichols, 1 slack box Aust. A bin in which fine coal (slack) is stored. slack-brake switch See: hoist slack brake switch slacken In metal smelting, the scoria of previous operations, mixed with the ores to retard or prevent fusion of the nonmetallic portions. Also spelled slakin. Standard, 2 slack hauler In bituminous coal mining, one who hauls small cars of slack (fine coal) from tipple to boiler room of power plant at mine to maintain fuel supply. DOT slacking a. Degradation in size (coal). Bennett b. Coals having a pronounced tendency to disintegrate or slack on exposure to weather, particularly when alternately wetted and dried or subjected to hot sunshine. Coals that slack readily contain relatively large amounts of moisture. When exposed to the weather, such coals lose moisture rapidly. As 2945

the coal loses moisture at the surface, the moisture from the interior of the piece gradually drifts outward to the surface. If the loss of moisture at the surface proceeds at a faster rate than that at which it is replaced by moisture from the interior of the piece, then the shrinkage of the coal at the surface is greater than that in the interior; consequently, stresses are generated in the surface coal. These stresses cause the coal to crack and disintegrate. Also called weathering. See also: weathering; weathering index. Mitchell slacking index See: weathering index slackline cableway a. A cableway having one low and one high tower and a track cable with adjustable tension suspended between them. One end of the track cable is attached to a hoist drum by means of which the tension on the cable can be rapidly changed so as to position, lower, or raise the digging skip. b. A cable excavator having a track cable that is loosened to lower the bucket and tightened to raise it. Nichols, 2 slack quenching The process of hardening steel by quenching from the austenitizing temperature at a rate slower than the critical cooling rate for the particular steel--resulting in incomplete hardening and the formation of one or more transformation products in addition to or instead of martensite. ASM, 1 slack water The state of a tidal current when its velocity is near zero, the moment when a current reverses direction. Sometimes considered the intermediate period between ebb and flood currents during which the velocity of the currents is less than 0.1 knot (0.16 km/h). Hy slag a. Material from the iron blast furnace, resulting from the fusion of fluxstone with coke ash and the siliceous and aluminous impurities remaining after separation of iron from the ore. Slag is also produced in steelmaking. Formerly a solid waste, slag is now utilized for various purposes, chiefly in construction. AGI b. A scoriaceous or cindery pyroclastic rock. AGI c. A British term for a friable shale with many fossils. AGI d. A substance formed in any one of several ways by chemical action and fusion at furnace operating temperatures: (1) in smelting operations, through the combination of a flux, such as limestone, with the gangue or waste portion of the ore; (2) in the refining of metals, by substances such as lime added for the purpose of effecting or aiding the refining; or (3) by chemical reaction between refractories and fluxing agents, such as coal ash, or between different types of refractories. Harbison-Walker e. Partially fused 2946

mixture of spilled batch, overflowed glass, breeze coal, and clay from the siege. ASTM f. The top layer of the multilayer melt formed during some smelting and refining operations. In smelting, it contains the gangue minerals and the flux; in most refining operations, the oxidized impurities. CTD g. Oxide liquids (exclusive of the commercial glasses) with a high melting temperature. Van Vlack h. See: blast-furnace slag; granulated slag. slag blanket The coating of slag, or scum, that forms on the top of the bath in the open-hearth furnace. Mersereau, 2 slag buggy A very large pot for holding slag obtained in the smelting or ores. It is mounted on a railway truck or the like, so as to permit easy dumping. See also: slag pot slag car Iron vessel on wheels used to transport molten slag from furnace to dump. Also called slag buggy. Pryor, 3 slag dump A dumping place for the shell or cone that forms in a slag pot. Standard, 2 slaggable Capable of becoming or forming into a slag. Fay slagging Destructive chemical reaction between refractories and external agents at high temperatures, resulting in the formation of a molten liquid. Henderson slagging of refractories Destructive chemical reaction between refractories and external agencies at high temperatures, resulting in the formation of a liquid. slag hearth A hearth, on the principle of the Scotch hearth, for the treatment of slags, etc., produced by lead smelting in the reverberatory furnace. The English slag hearth has one tuyere; the Castillian or Spanish, three. Fay 2947

slag inclusion Slag (dross) entrapped in a metal. ASM, 1 slag lead Lead obtained by a resmelting of gray slag. Fay slag pot A vessel for the disposal of slag at furnaces. Small pots are mounted on wheels and moved by hand, while the larger ones are mounted on trucks for mechanical transportation. See also: slag buggy; slag car. Fay slag runoff Tapping off excess slag after the ore boil in the basic open-hearth process of steelmaking. Bennett slake a. To crumble or disintegrate, such as coal or lime. b. Small coal. c. To mix with water, so that a chemical combination takes place, as in the slaking of lime. d. To crumble in water. Van Vlack slaking a. The crumbling and disintegration of earth materials upon exposure to air or moisture; specif. the breaking up of dried clay or soil when saturated with or immersed in water, or of coal or clay-rich sedimentary rocks when exposed to air. AGI b. The disintegration of the walls of tunnels in swelling clay, owing to inward movement and circumferential compression. AGI c. The treating of lime with water to give hydrated (slaked) lime. AGI slam Eng. Thin slurry and mud, Yorkshire lead mines. Arkell slant a. Any short, inclined crosscut connecting the entry with its air course to facilitate the hauling of coal. Commonly called a dip switch when the coal is not level. See also: shoofly b. A heading driven diagonally between the dip and the strike of a coal seam. Also called a run. See also: counter; stone drift; surface drift. Fay slant chute 2948

Chute driven diagonally across to connect a breast manway with a manway chute. See also: slant slant drilling See: directional drilling slants Eng. A set of joints in slate parallel to the main cleavage, Denbighshire. Arkell slant vein York. One vein crossing another at an acute angle. Arkell slape back Eng. See: back slash a. There are many successive ridges of shingle running in varying directions, and often with narrow strips of marsh enclosed between successive ridges. Such bands of marsh have been given the very appropriate name of slashes in New Jersey. AGI b. Swampy land, overgrown with dense underbrush. Local in the Northeast. AGI c. An open or cutover tract in a forest strewn with debris, as from logging; also such debris. AGI slat bucket A digging bucket of basket construction, used in handling sticky, chunky mud. Nichols, 1 slate a. A compact, fine-grained metamorphic rock that possesses slaty cleavage and hence can be split into slabs and thin plates. Most slate was formed from shale. AGI b. A coal miner's term for any shale accompanying coal; also, sometimes the equivalent of bone coal. AGI c. Dark shale lying next to the coalbeds. It contains impressions of the plant life of distant ages, proving the vegetable origin of coal. Korson d. A fine-grained metamorphic rock that breaks into thin slabs or sheets. Usually gray to black, sometimes green, yellow, brown, or red. Slates are composed of micas, chlorite, quartz, hematite, clays, and other minerals. Found in Pennsylvania, Vermont, Maine, Virginia, California, Colorado; Europe. Used for roofing; decorative stone; various building applications; in crushed form on shingles; abrasive; pigment. See also: clay slate; phyllite; spotted slate. CCD, 2 2949

slate chute a. A chute for the passage of slate and bony coal to a pocket from which it is loaded into dump cars. Fay b. A chute driven through slate. Fay slate cutter In the stonework industry, one who operates an upright drilling machine to drill holes into slate so that the slabs may be fastened in place with wires or rods when installed in a building. DOT slate ground A term used in southern Wales for a dark fissile shale, resembling slate. AGI slate handler In bituminous coal mining, a laborer who shovels up falls of slate or rock along haulageways in a mine and loads it into cars. Also called rock handler. DOT slate larryman See: slate motorman slateman In anthracite and bituminous coal mining, a general term for a worker handling slate or rock as distinguished from coal. Usually designated according to type of activity, as rock driller; rock loader; slate motorman; slate picker; slate shooter. Also called rockman; slate handler. See also: rockman; slate handler. DOT slateman helper See: slate-shooter helper slate motorman In anthracite and bituminous coal mining, a person who operates a mine locomotive to haul trains of cars loaded with slate or shale, underground and at the surface of a mine. Also called larryman; slate larryman. DOT slate saw See: marble saw 2950

slate shooter In bituminous coal mining, one who drills holes into the slate roof of haulageways, and charges and sets off explosives to blast down slate to increase height or improve the safety of the roof. DOT slate-shooter helper In bituminous coal mining, a laborer who assists the slate shooter in removing the slate and rock from the roof, ribs, and face of haulageways. Also called rockman helper; slateman helper. DOT slate spar A variety of crystallized calcite. Also called shiver spar. Standard, 2; Fay slat gate A gate, for controlling water, composed of two upright grooved posts with boards between the boards of slats being removed or added to regulate the height of water. slaty band Scot. Ironstone and flaky blaes. Nelson slaty cleavage A pervasive, parallel foliation of fine-grained, platy minerals (mainly chlorite and sericite) in a direction perpendicular to the direction of maximum finite shortening, developed in slate or other homogeneous sedimentary rocck by deformation and lowgrade metamorphism. Most slaty cleavage is also axial-plane cleavage. Syn: flow cleavage slave cylinder A small cylinder whose piston is moved by a piston rod controlled by a larger cylinder. Nichols, 1 slave piston A small piston having a fixed connection with a larger one. Nichols, 1 slave unit A machine controlled by or through another unit of the same type. Nichols, 1 2951

sleck a. Eng. A kind of reddish sandstone. b. Eng. Small pit coal. Arkell c. Newc. Mud deposited by water in a mine. d. See: slack sled A drag used to convey coal along the road to where it is loaded into cars, or to the chute. Also called sledge; slype. Fay sledger a. In bituminous coal mining, one who digs out dirt, rock, or coal with a long-handled pick (sledge) in a strip mine so that it may be loaded into cars by hand or with a power shovel. DOT b. In the quarry industry, one who breaks up large stone into small pieces suitable for use in building work. Also called laborer, stone; rock breaker; spawl beater; stone sledger. DOT sledging roll Crushing roll with projection that breaks the rock, instead of fracturing it by squeezing. Also called slugging roll. Pryor, 3 sleeping rent A fixed rent stated in leases of coal mines, as distinguished from royalty or share of profits. Standard, 2 sleeve catcher A skirt-type core lifter. Long slender beam A beam, which if overloaded, will fail by buckling of the compression flange. Hammond slew a. To turn around (slue). Mason b. See: slough slewing a. The rotation of a crane jib so that the load moves through the arc of a circle on a horizontal line. Hammond b. To turn or twist. 2952

slice a. To remove ore by successive slices from the top of an orebody of considerable lateral extent and thickness. The slices may be 6 ft, 12 ft, 20 ft, or 40 ft (1.8 m, 3.6 m, 6.1 m, or 12.2 m) thick. b. A thin broad piece cut off, such as a portion of ore cut from a pillar or face. slice bar A thin, wide iron tool for cleaning clinkers from the grate bars of a furnace. Standard, 2 slice drill In sublevel caving, the crosscuts driven between every other slice from 18 to 36 ft (5.47 to 10.94 m) apart. Lewis slicing In continuous mining, slicing consists of driving up some four to six places the set or desired distance, which may be 1,000 ft (304.8 m) or more, and then pulling the pillars on retreat. After completion of one slice, the unit moves over and mines another along the gob. See also: top slicing slicing-and-filling system See: overhand stoping slicing method Removal of a horizontal layer from a massive orebody. In top slicing extraction retreats along the top of the orebody, leaving a horizontal floor that becomes the top of the next slice. A timber mat separates this from the overburden, which caves downward as the slices are made. Other methods attack from the bottom (sublevel caving) or side. Pryor, 3 slick Ore in a state of fine subdivision. Syn: slime slickens Extremely fine-grained material, such as finely pulverized tailings discharged from hydraulic mines or a thin layer of extremely fine silt deposited by a stream during a flood. AGI 2953

slickensided clay See: stiff-fissured clay slickensides The striations, grooves, and polish on joints and fault surfaces. CF: striation slicker A small implement used in a foundry for smoothing the surface of a mold. Standard, 2 slick hole A hole column loaded with explosive, without springing. Nichols, 1 slicking A narrow vein of ore. Standard, 2 slick top In coal mining, a term used to describe the roof of the coal vein when it is very smooth. Kentucky slide a. An upright rail fixed in a shaft with corresponding grooves for steadying the cages. Fay b. A trough used to guide and to support rods in a tripod when drilling an angled hole. Also called rod slide. Long c. The bottom of a gold-washing cradle. Standard, 2 d. As used by churn drillers, a fault plane or opening encountered in a hole that deflects the bit. Long e. A mass movement of descent resulting from failure of earth, snow, or rock under shear stress along one or several surfaces that are either visible or may reasonably be inferred; e.g., landslide, snowslide, and rockslide. The moving mass may or may not be greatly deformed, and movement may be rotational or planar. A slide can result from lateral erosion, lateral pressure, weight of overlying material, accumulation of moisture, earthquakes, expansion owing to freeze-thaw of water in cracks, regional tilting, undermining, and human agencies. AGI f. The mass of material moved in or deposited by a slide. AGI slide coupling See: slip joint slide rail 2954

A mounting of steel or cast iron for a belt driven machine enabling it to be moved along as the belt stretches in order to take up the slack. Hammond slide rock Rock making up the mass of material in a landslide or talus. sliding angle Angle at or above which rock in movement will continue to slide, but less than the angle needed to initiate movement from rest. Pryor, 3 sliding friction Sliding friction is the resistance offered when one body slides over another body. The amount of friction or resistance is dependent on the laws of friction. Morris sliding gate A crest gate that has a high frictional resistance to opening and is therefore suitable only for small gates. See also: roller gate Hammond sliding scale A method of paying for the coal in proportion to the amount of lump coal it contains. Fay sliding-scale system A system which regulated colliers' wages by the ascertained selling price of coal. Nelson sliding shoe A metal plate that serves as partial or total support for devices used with shaker conveyors where the device must move or slide on the bottom. The shovel trough of a duckbill and certain types of swivels or angle troughs use this device. Jones, 1 slime a. Extremely fine sediment (#200 mesh), produced in the processing of ore or rock, esp. phosphate rock, which remains suspended in water indefinitely. Consists chiefly of clay. b. A material of extremely fine particle size encountered in ore treatment. ASM, 1 c. Anode slimes are the metals or metal compounds left at, or falling from, the anode during electrolytic refining of metals. See also: anode slime d. A mixture of metals and some insoluble compounds that forms on the anode in electrolysis. ASM, 1 e. A product 2955

of wet grinding containing valuable ore in particles so fine as to be carried in suspension by water; chiefly used in the plural. Webster 3rd f. In metallurgy, ore reduced to a very fine powder and held in suspension in water so as to form a kind of thin ore mud; generally used in the plural. g. Primary slimes are extremely fine particles derived from ore, associated rock, clay, or altered rock. They are usually found in old dumps and in ore deposits that have been exposed to climatic action; they include clay, alumina, hydrated iron, near-colloidal common earths, and weathered feldspars. Secondary slimes are very finely ground minerals from the true ore. Pryor, 2 slime coating In mineral processing, adherence of an impalpably fine layer of particles of another (for example, calcite on galena), therefore hindering or preventing true surface reaction in leaching or flotation. Pryor, 3 slime deliveryman In beneficiation, smelting, and refining, a laborer who washes slime from cloth strainers, electrolysis tank debris, and collection barrels into a settling tank, using a water spray preparatory to recovery of precious metals from slime. Becoming obsolete. DOT slime leaching A leaching method in which the slime and the leach solution are agitated in one or more agitators until the ore minerals have been dissolved. Some agitators have mechanically driven paddles or elevators inside an agitation tank, which serve to keep the pulp in circulation until dissolution is complete. This method may be either continuous or intermittent. Newton, 1 slime pit A tank or large reservoir of any kind into which the slimes are conducted in order that they may have time to settle, or in which they may be reserved for subsequent treatment. See also: slime slimer A machine that makes slime; e.g., a tube mill. Fay slime sludge a. The pulp or fine mud from a drill hole. b. See: slime slime table 2956

a. A table for the treatment of slime; a buddle. b. A shaking table used in gravity concentration of finely ground coal or ore, characterized by special riffles and shallow pools in which stratification is gently produced. Pryor, 3 slime tin Cassiterite too finely ground to be readily concentrated by the use of gravity treatment. Usually associated with hydrated iron. Pryor, 3 slime water Water defiled in washing ore. Standard, 2 slim hole a. A rotary borehole having a diameter of 12.7 cm or less. AGI b. A drill hole of the smallest practicable size, often drilled with a truck-mounted rig; used primarily for mineral exploration or as a stratigraphic or structure test. See also: structure test hole AGI slim-hole drilling and casing Use of the smallest feasible drill hole and casing size. Williams sliming Overgrinding in a ball mill. Newton, 1 sline a. Mid. Potholes in a mine roof. b. The principal cleat in coal. c. A natural transverse cleavage of rock; a joint. sling a. A rope or chain put around stones or heavy weights for raising them. Zern b. A lifting hold consisting of two or more strands of chain or cable. Nichols, 2 c. A ropelike device used to give additional support to lengths of drill rod too long to stand in the drill derrick without sagging unduly. Long d. A short loop or length of cable with small loops at either end. Long sling block A frame in which two sheaves are mounted so as to receive lines from opposite directions. Nichols, 1 2957

sling hygrometer See: Storrow whirling hygrometer sling psychrometer A hygrometer held on a short length of cord and whirled around, the observer standing sideways to the air current. The wet bulb is thereby rapidly reduced to its final reading. Hammond slink Scot. A wide clayey joint; a stage. slip a. Landslip, or subsiding mass of rock or clay in a quarry or pit; a minor landslide. b. A small fault. c. The relative displacement of formerly adjacent points on opposite sides of a fault, measured in the fault surface. See also: dip slip; strike slip. Partial syn: shift. Syn: total displacement d. A joint or cleat in a coal seam. e. See: kettle bottom f. A joint in coal upon which there may have been no perceptible movement. g. See: back h. A joint or pronounced cleavage plane. Mason i. A sudden descent of a hanging or sticking charge in a blast furnace. j. One of a set of serrated-face wedges that fits inside the spider of a drill-rod clamping device. See also: spider; slips. Long k. The percentage of water leaking through valves, expressed as a percentage of the volume swept out by the bucket or ram, a measure of the volumetric efficiency of a pump. Generally for normal pumping speeds, the slip is between 5% and 10% but it may rise to 20% with higher pumping speeds. Sinclair, 4 l. Under stress, minerals deform plastically along specific crystallographically determined slip planes in slip directions, analogous either to the sliding in a deck of playing cards, such as in quartz, or to a bundle of pencils, such as in olivine. Deformation lamellae may be preserved or destroyed by annealing. Although such slip is referred to as glide, it is not to be confused with a crystallographic glide--the combined symmetry element of translation and reflection. CF: glide; glide direction; glide plane; gliding. slip bowl A spider. See also: spider and slips slip-casting process One in which clay, or other slip, is poured into plaster molds that absorb the water, leaving a body the shape of the mold. slip clay 2958

An easily fusible clay containing a high percentage of fluxing impurities, used to produce a natural glaze on the surface of clayware. See also: slip slip cleavage a. That variety of foliation along which there has been visible displacement, usually shown by bedding that is cut by the cleavage. Such displacements are commonly shown along many adjacent cleavage planes. Billings b. Microscopic folding and fracture accompanied by slippage; quarrymen's false cleavage. c. S. Wales. The cleat of coal in planes parallel with slips or faults. d. A type of cleavage that is superposed on slaty cleavage or schistosity, and is characterized by finite spacing of cleavage planes between which occur thin, tabular bodies of rock displaying a crenulated cross-lamination. Syn: shear cleavage; strain cleavage; strain-slip cleavage; close-joints cleavage. AGI slip clutch A friction clutch that protects a mechanism by slipping under excessive load. Nichols, 1 slip dike A dike that has been intruded along a fault plane. AGI slip direction The crystallographic direction in which the translation of slip takes place. See also: glide direction slipes S. Staff. Sledge runners, upon which a skip is dragged from the working breast to the tramway. slip fiber Veins of fibrous minerals, esp. asbestos, in which the fibers are more or less parallel to slickensided vein walls. CF: cross fiber slip-fiber amphibole See: anthophyllite slip fold See: shear fold 2959

slip grip A hold or grip on a drill rod, casing, or pipe by means of serrated-face steel wedges or slips. Long slip joint a. A contraction joint between two adjoining sections of wall, or at the horizontal bearing of beams, concrete slabs, and precast units, to allow slight movement in relation to one of the other. Hammond b. A splined connection loose enough to allow its two parts to slide on each other to change shaft length. Nichols, 1 slip line Line that appears on the polished surface of a crystal or crystalline body that has been stressed beyond the elastic limit. In quantity, they represent the intersection of the surface by planes on which shear stress has produced plastic slip or gliding. Syn: Lueders line slip maker See: clay maker slip mixer See: clay maker slippage See: slip slippery parting Eng. See: back slipping cut In blasting underground, a cut used in a wide tunnel face, in which each successive vertical line of shots (round) breaks to the face made by the previous round, so that the relieving cut moves across the end being blasted. Also known as slabbing cut; swing cut. Pryor, 3 slip plane

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a. Closely spaced surfaces along which differential movement takes place in rock. Analogous to surfaces between playing cards. Syn: glide plane; gliding plane. Billings; AGI b. The crystallographic plane in which slip occurs in a crystal. ASM, 1 slip process See: wet process slips a. Small faults. BS, 11 b. A tool used at the mouth of a borehole to grip the drill rods or the casing, as these are being inserted or withdrawn. BS, 9 c. See: backs; slickensides. slip spear A tool for extracting tubing from a borehole. slip surface The surface along which an earth bank is liable to fail under load. Hammond slip surface of failure In a bank of homogeneous earth or clay, the slip surface of failure closely follows the arc of a circle that usually intersects the toe of the bank. Stability depends upon fixing the position of the center of rotation of the slip surface along which the greatest shearing resistance would be required for equilibrium. See also: circular slip; landslide. Nelson slip switch A sensor installed on a conveyor drive pulley snub roller, on a return roller, on a bend roller, or on a head pulley that will detect a slowing of the conveyor, resulting in conveyor shut-down to avoid conveyor belt fires or overloading of the conveyor because of the slipping. slip-type core lifter A device used like a core spring, consisting of a series of tapered wedges contained in slotted recesses in a circular ring or sleeve; as the core enters the inner tube, it lifts the wedges along the taper, and when the barrel is lifted, the wedges are pulled tight against the core. Long slip vein A mineral vein accompanied by faulting or dislocation. 2961

slip velocity The rate, expressed in feet (meters) per minute, at which a given size and shape of rock particle will descend or settle in water; e.g., the slip velocity in water of a round, flat particle of rock, 1/2 in (1.27 cm) in diameter, is about 54 ft/min (16.5 m/min). Long slit-side solid sampler A solid-tube sampler with a slight twist on the bottom and an offset slit in the side. When rotated, the lip of the slit scrapes a sample from the side of a borehole. Long slitter Eng. A pick. Fay slitting disk Circular saw used in preparing rock specimens. The cutting edge incorporates diamond dust, and the thin steel disk revolves at high speed. Pryor, 3 slitting shot A shot put into a large mass of coal detached by a previous blast. slocking stone Eng. A piece of rich ore used to tempt persons into a mining enterprise. See also: salting a mine slope a. The entry, passage, or main working gallery of a coal seam that dips at an angle. See also: incline b. Inside slope. c. See gradient. d. An inclined passage driven from the dip of a coal vein. CF: slant When not open at one end to the surface, it is known as an inside slope. See also: incline; plane. e. The inclination of a mine roadway or coal seam. Nelson f. The main working gallery or entry of a coal seam that dips at an angle and along which mine cars are hauled. Nelson g. An entrance to a mine driven down through an inclined coal seam; also, a mine having such an entrance. An inside slope is a passage in the mine driven through the seam by which coal is brought up from a lower level. Korson h. In a mining statute or in mining parlance, an inclined way, passage, or opening used for the same purpose as a shaft. Sometimes used to embrace the main haulage passageway, whether inclined or level. Ricketts i. The degree of inclination to the horizontal. Usually expressed as a ratio, such as 1:25, indicating one unit rise in 25 units of horizontal distance; or in a decimal fraction (0.04); degrees (2 degrees 18'); or percent (4%). It is sometimes expressed as steep, moderate, gentle, mild, flat, etc. Also 2962

called gradient. Hunt j. In surface mining, the steepest possible slope of an excavation that is consistent with safety of working. Mining k. An inclined passageway (tunnel) from the surface, through the strata, that intersects the coal bed to be developed. slope air course A passageway parallel to the haulage slope used for the passage of the air current. slope cage A truck on which the cars are raised at slopes or steep dips. Also called slope carriage. See also: carriage slope conveyor a. Usually a troughed belt conveyor used for transporting coal or ore through an inclined passage to the surface from an underground mine. See also: apron conveyor; belt conveyor; flight conveyor. b. Generally less than 1,000 ft (304.8 m) in length, the conveyor is designed to raise or lower material on steep grades and is commonly used to transport material from discharge bins or a main haulage conveyor to the outside. It is often used as a transfer conveyor from a lower to a higher entry or to a gangway in a pitching seam. NEMA, 2 slope correction A calculation of deduction from a length as measured on a slope to bring it to its true horizontal length. See also: tape corrections slope engineer In anthracite and bituminous coal mining, one who operates a hoisting engine to haul loaded and empty mine cars along a level or inclined haulage road (slope or plane) in a mine on a level, or from a lower to an upper level, or to the mine surface. Also called drag engineer; dragline engineer; drumman; plane engineer; plane tender; slope tender. DOT slope failure a. The downward and outward movement of rock or unconsolidated material as a unit or as a series of units. Also called slump. Leet, 1 b. Failure of the mass of soil beneath a natural slope or a slope of an embankment by the formation of a slide. Huntington c. Slope failure may take place by one or more of three processes: (1) raveling, in which the material will assume an angle of repose approx. equal to the angle of friction of the material, and within limits the stable slope is independent of the weight of the mass, the height of the slope, and the size of the fragments. It is, however, characteristic of each 2963

rock material and is dependent on angularity, grading, and mineral content; (2) transitional failure, in which failure occurs mostly along existing fault planes or other planes of weakness. Stability is a function of rock cohesion, the angle of internal friction, the angle of dip of the slip plane, the length of the slip surface, and the total weight of the block; and (3) rotational or base failure, which is uncommon in open-pit mines or rock cuts because of geologic structure. However, in the case of homogeneous cohesive material--very deep excavation or low rock strength--failure may occur along a cylindrical surface. Four types of slope failure are rockfall, rock flow, plane shear, and rotational shear. See also: rockfall; rock flow; plane shear; rotational shear. Syn: base failure d. Gradual or rapid downslope movement of soil or rock under gravitational stress, often as a result of man-caused factors; e.g., removal of material from the base of a slope. AGI slope gage A staff gage placed on an incline and graduated to indicate vertical heights. Seelye, 1 slope hoist See: direct-rope haulage slope mine a. A mine opened by a slope or incline. b. A mine with an inclined opening used for the same purpose as a shaft or a drift mine. It resembles a tunnel, a drift, or a shaft, depending on its inclination. Kentucky slope stability a. The resistance of any inclined surface, as the wall of an open pit or cut, to failure by sliding or collapsing. b. The resistance of a natural or artificial slope or other inclined surface to failure by landsliding. AGI slope stake a. Stake set at the point where the finished side slope of an excavation or embankment cuts the surface of the ground. It is usually placed on a line at right angles to the center line and passing through the station point. Seelye, 2 b. A stake marking the line where a cut or fill meets the original grade. Nichols, 1 slope staking Marking the ground surface by pegs at points where proposed new slopes in cut or fill coincide with the orginal surface. Hammond 2964

slope tender See: slope engineer slope test A test to determine whether, and to what extent, the course of a well deviates from vertical. Syn: angularity test sloshing loss A loss occurring when there is a fluid in the pores of the rock. This loss arises from the relative movement of the fluid and solid as the elastic waves pass through the rock. Wyllie slot A narrow, vertical opening generally too small to permit traverse by a person. AGI slot-and-wedge bolt A special rod designed for use in roof bolting. It consists of a mild steel rod, threaded at one end, the other end being split into halves for a length of about 5 in (12.7 cm). When the bolt is driven into the hole, a wedge opens the slotted end, thus forming the anchorage. See also: bolt; wedge-and-sleeve bolt. Nelson slot dozing A method of moving large quantities of material with a bulldozer. Each trip is made in the same path; thus the spillage from the sides of the blade builds up along each side. All material pushed into the slot is retained in front of the blade; bigger loads are handled. Nelson slotted duct sampler An instrument for sampling airborne dust consisting of a wide horizontal duct through which mine air enters in a streamline flow, so that dust particles will be deposited on the duct floor according to their falling speeds as derived from Stokes' law. The instrument combines the duties of monitoring and measuring airborne dust concentrations in mine roadways. See also: thermal precipitator slough

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Fragmentary rock material that has crumbled and fallen away from the sides of a borehole or mine working. It may obstruct a borehole or be washed out during circulation of the drilling mud. Pron: sluff. AGI sloughing Minor face and rib falls. Coal Age, 3 sloughing-off cone Large cone (e.g., Callow) in pulp flow line designed to remove fine slimes as overflow while delivering a thickened spigot product containing the coarser particles. Pryor, 3 slovan a. Corn. The outcrop or back of a lode. This generally applies to the appearance of a lode in a marshy place. b. A gallery in a mine; day level; esp. applied to damp places. Standard, 2 slow-banking device An appliance for use in conjunction with the Lilly controller for controlling the landing speed of less than 5 ft/s (1.52 m/s) when workers are being transported by winding. On each dial of the Lilly controller, an auxiliary dial is bolted to carry a slow-banking cam engaging near the end of the wind with a roller arm. The action of the appliance depends on the relative rate of movement of this roller and that of the piston in an oil dashpot cylinder. Sinclair, 5 slow gear a. When applied to speed at which the drill motor rotates the drill stem, the transmission gear position giving the lowest number of bit revolutions per minute; thus, slow gear corresponds to low gear in an automobile. Long b. When applied to a screwfeed-type drill, the pair of feed gears in the feed mechanism that advances the bit the least amount for each revolution of drill drive rod and/or the coupled drill stem; e.g., a 400-feed gear is slower than a 100-feed gear. CF: feed ratio slow igniter cord It consists of a plastic incendiary composition extruded around a central copper wire. An iron wire is added to give greater strength, and the whole is then enclosed in a thin extruded plastic coating. The diameter of slow cord is 0.07 in (1.8 mm). McAdam, 2 slow powder 2966

Blackpowder, often called gunpowder. Also, some of the slow-acting dynamites. Nichols, 1 sludge a. Refuse from a coal-washing plant. Standard, 2 b. In diamond drilling, the portion of core ground finely by accident or defect in drilling, and therefore reducing the reliability of the portion of the sample in which it happened. Mineral mud, slurry too thick to flow. Pryor, 3 c. Rock cuttings produced by a drill bit. BS, 9 d. See: cuttings e. A semifluid, slushy, murky mass of sediment resulting from treatment of water, sewage, or industrial and mining wastes; often appearing as local bottom deposits in polluted bodies of water. AGI f. See: slime sludge abatement The control of the discharge into watercourses (or on adjacent land), of mineralized or impure water, or sludge, or mining debris. Nelson sludge assay The chemical assaying of drill cuttings for a specific metal or group of metals. Long sludge barrel a. See: sediment tube b. See: calyx sludgebound Any part of the drill-string equipment clogged by impacted cuttings. Long sludge box a. A wooden box in which the sludge is allowed to settle from the mud flush and sometimes retained for examination. Nelson b. See: settling box sludge bucket See: calyx sludge channel A tailrace for conveying the tailings away after the gold has been extracted from alluvial beds. sludge mill 2967

A machine in which the sludge (slime) from another mill is washed; as, e.g., a slime table. sludge paddocks Collecting or settling areas for the slurry which results from hydraulicking overburden. Austin sludge pit See: sump sludge pump Short iron pipe or tube fitted with a valve at the lower end, with which the sludge is extracted from a borehole. Also called bailer, mud pump. See also: mud hog; sand pump. sludger a. A long cylindrical tube, fitted with a valve at the bottom and open at the top, used for raising the mud that accumulates in the bottom of a boring during the sinking process. Also called sand pump; shell pump; sludge pump. CTD b. A scraper for clearing mud out of a shothole. CTD c. A centrifugal pump designed for dealing with sand and slime. See also: bailer sludge sample a. Samples of mud from a rotary drill, or sand from a churn drill, or fine materials from diamond drilling used to obtain information about the formation being drilled. Nichols, 1 b. All or part of the drill cuttings collected, dried, and saved for assaying or chemical analysis. Long c. The mud and chippings made during boring with a diamond or churn drill and sometimes used for sampling purposes. Little reliance can be placed on the assay of the sludge, and it is not regularly saved for assay, except occasionally when drilling in weathered or friable ore zones. Sludge tanks are often used to collect sludge samples. Nelson sludge sampler a. An individual responsible for collecting and preparing drill cuttings for the purpose of examining, assaying, chemical analysis, or storage. Also called sampler. Long b. A device used to collect and to split drill cuttings. See also: riffle sludge sampling Process of collecting and preparing drill cuttings as samples. Long 2968

sludge-saver A device for collecting all the drill cuttings from a given interval of borehole. Long sludge splitter See: rifle sludge water See: return water sludging Filling or choking the waterways of a bit with drill cuttings; mudding up. sludging formation A formation from which it is nearly impossible to recover core, so that sampling is done by collecting the drill cuttings or sludge. Long sludging up See: sludging slue To turn, twist, or swing about. To slide and turn or slip out of course. In cutting the coal, the machine moves from right to left, the back part moving faster than the front. It is necessary at intervals to stop the machine and straighten it, or "slue" it, as called by miners. sluff a. Mud cake detached from the wall of a borehole. Long b. A variant, incorrect spelling of slough. Long c. The falling of decomposed, soft rocks from the roof or walls of mine openings. slug a. A piece of alluvial gold up to about 1 lb (0.45 kg) weight. Gordon b. A lump of metal or valuable mineral. c. To inject a borehole with cement slurry or various liquids containing shredded materials in an attempt to restore lost circulation by sealing off the openings in the borehole-wall rocks. Long d. Small, shaped pieces of hard metal that can 2969

be brazed or handpeened in slots or holes cut in the face of a blank bit. Slugs may or may not contain diamonds. CF: insert e. A mass of half-roasted ore. Webster 3rd slug bit See: insert bit slugga An Irish term for a hole in the ground surface, caused by the falling-in of limestone over a subterranean stream. CF: sinkhole slugger A tooth on a roll-type rock crusher. Nichols, 1 sluice a. To mine an alluvial deposit by hydraulicking. Nelson b. A conduit or passage for carrying off surplus water, often at high velocity. It may be fitted with a valve or gate for stopping or regulating the flow. AGI c. A gate, such as a floodgate. AGI d. A body of water flowing through or stored behind a floodgate. AGI e. A long troughlike box set on a slope of about 1:20, through which placer gravel is carried by a stream of water. The sand and gravel are carried away, while most of the gold and other heavy minerals are caught in riffles or a blanket on the floor. See also: box sluice; ground sluice; placer mining. Nelson f. See: flume g. An opening in a structure for passing debris. Seelye, 1 h. A channel, drain, or small stream for carrying off surplus or overflow water. Craigie sluicebox Long, inclined trough or launder containing riffles in the bottom that provide a lodging place for heavy minerals in ore concentration. The material to be concentrated is carried down through the sluices on a current of water. Sluiceboxes are widely used in placer operations for concentrating elements such as gold and platinum, and minerals such as cassiterite, from stream gravels. Newton, 1 sluice fork A form of fork having many tines, used to remove obstructions from a sluiceway. sluice gate The sliding gate of a sluice. Webster 3rd sluice head 2970

Aust. A supply of 1 ft3 /s (0.028 m3 /s) of water, regardless of the head, pressure, or size of orifice. CF: miner's inch sluice tender In metal mining, a laborer who tends sluiceboxes (troughs) used in placer mining to separate gold from the sand or gravel in which it occurs; and removes wood and other obstructions to see that the gravel and water run freely through the sluices and that the riffles (cleats) are clear, so that the gold will be caught and held when settling to the bottom. DOT sluiceway An artificial channel into which water is let by a sluice. Webster 3rd sluicing Concentrating heavy minerals by washing unconsolidated material through a box (sluice) equipped with riffles that trap the heavier minerals on the floor of the box. AGI slum a. The very finely divided clayey portion of the residue overflowing from a sluice box, particularly applied to deep lead mining. Nelson b. A short roadway to the dip in coal mines used solely to stock spare cars or the spake until required at the end of the shift. Nelson c. A soft clayey or shaley bed of coal. Also spelled slumb. d. Used in the plural for the discharge or waste from hydraulic mines. See also: tailing; slime. slumgullion A usually red, muddy deposit in mining sluices. Webster 3rd slump a. A landslide characterized by a shearing and rotary movement of a generally independent mass of rock or earth along a curved slip surface (concave upward) and about an axis parallel to the slope from which it descends, and by backward tilting of the mass with respect to that slope so that the slump surface often exhibits a reversed slope facing uphill. Syn: slumping b. The mass of material slipped down during, or produced by, a slump. AGI slump bedding A term applied loosely to any disturbed bedding; specif. deformed bedding produced by subaqueous slumping or lateral movement of newly deposited sediment. AGI 2971

slumping The downward movement, such as sliding or settling, of a slump. Syn: slump slung cartridges Cartridges of explosive lowered into position in drill hole blasting at the end of a length of strong twine (not wire). As detonating cord is normally used for ignition in drill holes, the primed cartridge is lowered first in each charge by using a detaching hook or a length of twine, and it is followed by the remainder of the charge. Nelson slurry a. The fine carbonaceous discharge from a mine washery. All washeries produce some slurry, which must be treated to separate the solids from the water in order to have a clear effluent for reuse or discharge. See also: sludge b. Fine particles concentrated in a portion of the circulating water (usually by settling) and waterborne to treatment plant of any kind. BS, 5 c. A thin watery suspension; e.g., the feed to a filter press or other filtration equipment. CCD, 2 slurry blasting agents Dense, insensitive, high-velocity explosives of great power and very high water resistance. They are usually mixtures of an explosive such as TNT, which is a reducing agent, or an oxidizing agent, such as ammonium nitrate and/or sodium nitrate, and water. A thickening or jelling substance such as guar gum is usually added. Slurries may also be made with nonexplosive reducing agents, including finely divided metals such as magnesium or aluminum, and with organic compounds such as sugar, molasses, or emulsified oil. These slurries are used chiefly in open pit mines where rock is hard and/or holes are wet. Also called DBA (dense blasting agent). Nichols, 1 slurry helper A laborer who makes slurry for use by furnace sprayer, mixing specified amounts of silica, clay, and water in large drums with air-pressure hose. DOT slurrying The process of filling in joints with slurry. Osborne slurry man See: furnace sprayer slurry pond 2972

Any natural or artificial pond or lagoon for settling and draining the solids from washery slurry. BS, 5 slurry screen A screen to recover a granular product from the circulating water in a washer, usually after a preliminary concentration of the solids and with or without the use of water sprays. BS, 5 slush a. To fill mine workings with sand, culm, or other material, by hydraulic methods. See also: hydraulic mine filling b. Silt. c. To move ore or waste filling with a scraper (slusher) hoist. slusher a. See: scraper loader b. A mechanical dragshovel loader. Mason c. A mobile drag scraper with a metal slide to elevate the bucket to dump point. Nichols, 1 slusher drift Drift in stope block above haulage level, down which scraper loader conveys broken ore to loading chutes, which are usually without gates. Pryor, 3 slusher operator In metal mining, one who operates the hoisting engine of a scraper loader, known as a slusher, to load ore into cars or to scrape it into chutes, or to move sand or rock fill in the stopes. DOT slushing Term sometimes applied to hydraulic stowing and also to scraper loader operations. Nelson slushing drift A drift in an orebody, equipped wth a scraper loader, for loading ore directly into cars in the haulage level. The drift is formed at right angles to the haulage level and over it so that the ore drops into the cars. Nelson slushing oil

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Used to coat metals, machine parts, etc., to prevent corrosion. It usually is nondrying oil or grease, which coats the metal very well but is easily removed when desired. Crispin slush pit An excavation dug near a drill to form a reservoir in which the returns from a borehole are collected and stored. Also called drill sump, mud pit, sludge pit, slush pond, sump. Long slush pond See: slush pit; sump. sly bed Eng. Soft, black, bituminous shale with a white efflorescence on exposure. A hard calcareous band near the base, Middle Purbeck Beds, Swanage. Arkell small coal a. Coal broken into small pieces, usually smaller than stove size; slack. Standard, 2 b. Coal with a top size less than 3 in (7.6 cm). BS, 2 small colliery Gr. Brit. Generally a colliery producing less than 1,000 st/d (907 t/d). See: large colliery small-diameter blastholes Multiple row blasting with holes 1 to 3 in (2.5 to 7.6 cm) in diameter in low-face quarries. Short-delay blasting is usually adopted using explosive factors similar to those of large diameter holes. With smaller diameter blastholes, the explosive charges can be brought up higher in the holes and so provide better breakage in blocky ground. Nelson Smalley process A method for desulfurizing iron and steel with metal hydrides in which a molten slag is floated on a mass of molten ferrous metal and at least one metal hydride is introduced into the mass. The molten ferrous metal is separated from the slag, the metallic hydrides breaking down into metal and nascent hydrogen. Hydrides of the alkali metals have been found very satisfactory and are readily available. Osborne small mine A coal mine employing not more than 50 persons below ground. 2974

small ore Eng. Copper, lead, and zinc ore dressed to a small size. See also: smalls smalls a. Small coal; slack. Standard, 2 b. One of the three main size groups by which coal is sold by the National Coal Board of Great Britain. It embraces all coals with no lower size limit and ranges from a top size of 2 to 1/8 in (50 to 3.3 mm), and can be either untreated, i.e., have received no preparation other than dry screening; or treated, having been washed or dry cleaned. See also: graded coal; large coal. Nelson c. Small particles of mixed ore and gangue. Standard, 2 d. See: small ore small-stone bit In mineral exploration drilling, a diamond bit set with 100% size or smaller diamonds. Long small tin Eng. Tin recovered from slimes. smaltine An arsenide of cobalt, often containing nickel and iron. Also called gray cobalt; tin-white cobalt. See also: smaltite smaltite a. Arsenic-deficient variety of skutterudite. Syn: smaltine; tin-white cobalt; gray cobalt; white cobalt; speisscobalt. b. A general term for undetermined, apparently isometric, arsenides of cobalt or for a mixture of cobalt minerals. smaragd a. A precious stone of light green color; a variety of beryl. Fay b. See: emerald smaragdite A thin-foliated variety of amphibole, near actinolite in composition but carrying some alumina. It has a light green color resembling much common green diallage. Fay smart aleck

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A limit switch that cuts off power if a machine part is moved beyond its safe range. Nichols, 1 smashup A wreck, usually of haulage equipment. smectic state Liquid-crystalline state of some fatty acids and soaps in which bundles of long molecules are oriented into parallel layers. Smectic liquid crystals are composed of a series of planes. They glide rather than flow. When less completely oriented (nematic), they are distributed at random and flow. Pryor, 3 smectite a. Any clay mineral with swelling properties and high cation-exchange capacities; an expansive clay. b. A term originally applied to fuller's earth and later to montmorillonite; also to certain clay deposits that are apparently bentonite, and to a greenish variety of halloysite. c. The mineral group beidellite, hectorite, montmorillonite, nontronite, pimelite, saponite, sauconite, sobotkite, stevensite, and swinefordite. smeddum a. Fine particles of coal or ore. b. Fine coal slack. Also spelled smiddam; smiddum; smitham; smithem; smitten; smytham. Standard, 2 smelt See: smelting smelter a. Person engaged in smelting or works in an establishment where ores are smelted. Fay b. An establishment where ores are smelted to produce metal. Fay c. A furnace in which the raw materials of the frit batch are melted. See also: batch smelter; continuous smelter; rotary smelter. ASTM smelter returns In a contract, returns from the ore, less the smelting charges, without deducting transportation charges. Ricketts smelting 2976

a. The chemical reduction of a metal from its ore by a process usually involving fusion, so that earthy and other impurities separate as lighter and more fusible slags and can readily be removed from the reduced metal. An example is the reduction of iron ore (iron oxide) by coke in a blast furnace to produce pig iron. Smelting may also involve preliminary treatment of ore, such as by calcination and further refining processes, before the metal is fit for a particular industrial use. Rolfe b. A process distinct from roasting, sintering, fire refining, and other pyrometallurgical operations. The two most important types are reduction smelting, which produces molten metal and molten slag, and matte smelting, which produces molten matte and molten slag. Smelting may be conducted in a blast furnace, a reverberatory furnace, or an electric furnace. Reduction smelting is usually performed in blast furnaces and matte smelting in reverberatories, but there are exceptions in both cases. Syn: smelt smelting furnace A blast furnace, reverberatory furnace, or electric furnace in which ore is smelted for the separation of a metal. Standard, 2 smelting works An establishment in which metals are extracted from ores by furnaces. Standard, 2 smiddam Derb. Lead-ore dust. A variation of smeddum. smiddum Eng. A variation of smeddum. smiddum tails Eng.; Scot. Ore sludge; ore slime. A variation of smeddum. Smidth agglomerating kiln A rotary kiln providing an alternative method to sintering for the treatment of fine ores and flue dust. Osborne smith forge A small, open-hearth furnace utilizing an air blast with coal or coke for fuel. It is commonly used for heating small metal parts previous to manual, hot-working operations. Henderson 2977

smithite A monoclinic mineral, AgAsS2 ; dimorphous with trechmannite; red. Smith process a. A variation of the series system of copper refining in which the plates are placed horizontally, the top surface of each one acting as cathode, the lower as anode. Linen diaphragms must be placed between the plates to catch the slime. When these diaphragms break and allow the slime to drop on the cathode, it is difficult to remedy any short circuits without dismantling the tank. Liddell b. A process for sponge iron production that is carried out in vertical ovens or retorts, similar to coke ovens in design. Crushed ore or iron oxide material is mixed with carbonaceous material and charged into the oven, where it is heated and cooled by means of horizontal flues. It is preheated in the upper part of the oven by the waste gases; then the charge enters the reduction zone, and is subsequently cooled by the incoming air for combustion in the heating flues. Osborne smithsonite a. A white to yellow, or to brown and rarely green or blue variety of zinc carbonate. See also: zinc carbonate b. A trigonal mineral, ZnCO3 , with Zn replaced by Fe; of the calcite group; rhombohedral cleavage; varicolored; commonly reniform, botryoidal, stalactitic, or granular; commonly altered from sphalerite in oxidized zones of limestone replacement; a source of zinc; distinguished from hemimorphite by its effervescence in acids. Syn: dry-bone ore; calamine; zinc spar; szaskaite. c. A term sometimes used as a syn. of hemimorphite. smitten Fine gravellike ore, occurring free in mud openings, or derived from the breaking of the ore in blasting. A variation of smeddum. smoke The exhalation, visible vapor, or material that escapes or is expelled from a burning substance during combustion; applied esp. to the volatile matter expelled from wood, coal, peat, etc. together with the solid matter that is carried off in suspension with it. That which is expelled from metallic substances is generally called fume or fumes. See also: fume; metallurgical smoke. smokeless powder Nitrocellulose containing 13.1% nitrogen. Produced by blending material of somewhat lower (12.6%) and slightly higher (13.2%) nitrogen content; converting to a dough with 2978

an alcohol-ether mixture; extruding; cutting; and drying to a hard, horny product. Small amounts of stabilizers (amines) and plasticizers are usually present, as well as various modifying agents (nitrotoluene and nitroglycerin salts). CCD, 2 smoke stick A means of making a smoke cloud to measure the velocity of air. Fuming sulfuric acid or anhydrous tin tetrachloride are favorite smoke producers. Zern smokestone See: cairngorm; smoky quartz. smoke technique A technique used to measure only very low-speed air velocity. The release of smoke enables the fluid motion to be observed with the eye. If the smoke is timed over a measured distance along an airway of constant cross section then the velocity of flow can be determined. Usually a spot reading, that of maximum velocity, is obtained. Roberts, 1 smoke tester One who tests the efficiency of the Cottrell plant and flue recovery method by determining the rate of discharge of gases and solids from the smelter smokestack. DOT smoke tube To determine the presence of moving air, the direction of flow, and the approximate velocity of flow, the smoke tube method is commonly used, particularly in metal mines. The device consists of an aspirator bulb, which discharges air through a glass tube containing a smoke-generating reagent. Usually pumice stone saturated with anhydrous tin or titanium tetrachloride is employed. The dense white cloud of smoke released when the bulb is squeezed travels with the air current; the approximate air velocity in a mine airway is determined by timing how long the cloud takes to travel between two points. Hartman, 2 smoke washer A device in which smoke is forced upward against a downward spray of water in order to remove the solid particles in the smoke. Webster 3rd smoke zone

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The area surrounding a smelting plant in which the smoke or fumes damage vegetation, or in which it may be classed as a public menace or nuisance. Fay smoky quartz A light to very dark brown variety of quartz sometimes used as a semiprecious gemstone. Syn: cairngorm; smokestone. smoky topaz A trade name for smoky quartz used for jewelry. smooth blasting A technique used in surface and underground blasting in which a row or closely spaced drill holes are loaded with decoupled charges (charges with a smaller diameter than the drill hole) and fired simultaneously to produce an excavation contour without fracturing or damaging the rock behind or adjacent to the blasted face. See also: controlled blasting smooth drilling A rock formation in which a high recovery of core can be attained at a high rate of penetration. Long smoother bar A drag that breaks up lumps behind a leveling machine. Nichols, 1 smooth-faced drum Plain-faced drum without grooves. Hammond smooth head York. A smooth plane of cleavage. See also: bright head smoothing trowel Trowel used by plasterers and cement workers for finishing surfaces. Crispin smooth roll A crusher in which the material passes between a moving set of rolls with smooth surfaces. See also: roll 2980

S.M.R.E. combustible gases recorder This methane recorder is a combination of the principles used in the Ringrose and McLuckie detectors. Two combustion chambers are used, each of which operates every 6 min, the operation being staggered so that 20 determinations are made per hour. Samples are drawn into the instrument by means of an electrically driven pump, the operation of the pump and the combustion filaments being controlled by cams on a shaft driven by the motor. Pressures are measured by an aneroid cell and recorded on a clockwork driven drum. Roberts, 1 smut a. Soft, inferior coal. b. S. Staff. Bad, soft coal, containing much earthy matter. See also: muck c. Coal smuts. CTD d. Worthless outcrop material of a coal seam. CTD e. Poor, dull, sooty portions of a coal seam. Gordon f. A reaction product sometimes left on the surface of a metal after a pickling or etching operation. ASM, 1 smytham Lead ore that has been stamped or pounded down to a sand or powder to remove rock and earth from the ore. Hess smythite A trigonal mineral, (Fe,Ni)9 S11 or (Fe,Ni)13 S16 ; physical properties are almost identical with monoclinic pyrrhotine. snag boat A boat equipped with a hoist and grapple for clearing obstacles from the path of a dredge. Nichols, 1 snake fashion A method of boxing core. Beginning in the upper-right-hand corner of the core box the core is run from right to left in the first row, from left to right in the second row, left to right in the third, etc., until the box is filled. CF: reverse book fashion snakehole a. A borehole driven horizontally or nearly so and approx. on a level with the quarry floor. b. A borehole driven under a boulder for containing a charge of explosives. In quarry work, it is called a lifter. c. Nearly horizontal holes drilled at the bottom of the face of a bench. The holes are not quite horizontal but are inclined slightly downward so 2981

the bottoms will be a few feet below grade. Lewis d. A hole driven into a toe for blasting, with or without vertical holes. Nichols, 1 snakeholing a. A method of blasting boulders to break them up, by boring a hole under a boulder and firing a charge in it; this is more efficient but slower than using plaster shots. See also: plaster shooting b. A horizontal bore on the quarry floor. Pryor, 3 c. Drilling under a rock or face in order to blast it. Nichols, 1 snake line A line used to skid a drill rig from place to place using a block and tackle or cable, one end of which is attached to a deadman and the other wrapped around the hoisting drum. Long snake statement A monthly statement by a coal company on which a crooked line in red ink was drawn to show a miner's indebtedness. The company checked off rent, supplies, and groceries, which often added up to more than a miner's monthly earnings. Korson snaking a. The progressive sliding forward of an armored flexible conveyor, by means of hydraulic rams, as the coal is removed by a cutter loader. See also: self-advancing supports b. Moving a drill rig by the use of its own cathead or hoist unit. See also: bulldog c. Towing a load with a long cable. Nichols, 1 d. Inserting a tow or hoist line under an object without moving the object. Nichols, 1 snaking conveyor See: armored flexible conveyor snaphead rivet A rivet having a hemispherical head. Hammond snapper a. A car coupler, trip rider, or brakeman. b. See: grab sampler snatch block

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a. A pulley in a case that can be easily fastened to lines or objects by means of a hook, ring, or shackle. Nichols, 1 b. A single-rope sheave set in a housing provided with a latch link, which can be opened for admission of a rope or line without the necessity of threading the end of the rope through the block. Long c. A block or sheave with an eye through which lashing can be placed for fastening to a scaffold or pole. Hammond d. A sheave in a case having a pull hook or ring. Nichols, 1 sneck a. The latch or catch of a door. Webster 3rd b. To lay (rubblework) with spalls and fragments to fill the interstices. Webster 3rd Snell's law a. The concept that the ray path of sound or light undergoes certain specific changes as it passes through different layers of water; the ratio of the sine of the angle of incidence to the sine of the angle of refraction is the same for all angles of incidence and is equal to the index of refraction. Hy b. Ordinary refraction where the index of refraction equals the sine of the angle of incidence divided by the sine of the angle of refraction. Syn: law of refraction snorehole The hole in the lower part of the windbore of a mining pump to admit the water. snort valve A butterfly valve opening from the cold-blast main of a blast furnace to the atmosphere. It allows casting at the furnace without shutting down the blowing engines; operated by large wheel or lever in the cast house. Fay snow Vapor-deposited skeletal ice crystals without a substrate; their accumulation; used for recreation and as a coolant. See: ice snow gage See: rain gage snub a. To increase the height of an undercut by means of explosives or otherwise. Fay b. To check descent of a car, by a turn of a rope around a post. CF: jig chain c. To check the descent of any object being lowered by hand. 2983

snubber In bituminous coal mining, a laborer who follows in the wake of a coal-cutting machine as it undercuts the face of coal, and breaks down the front of the working face above the channel with a pick so that the coal will drop freely when it is blasted. DOT snubbing a. A term applied by bluestone quarrymen to the process of forcing a cross break in the absence of an open seam. b. Increasing the height of an undercut by picking or blasting down the coal, just above the undercut. snub-drive conveyor A conveyor in which a snub pulley is used. NEMA, 1 snub pulley An idler pulley so mounted as to increase the arc of contact between a belt and a drive pulley. When used in a wrap drive, it has the added function of changing the direction of the return belt travel. NEMA, 2 Snyder sampler A mechanical sampler consisting of a cast-iron plate revolving in a vertical plane on a horizontal axis, and having an inclined sample spout passing through the flange. The ore to be sampled comes to the sampler by way of an inclined chute and impinges upon the flange of the sampling disk. Whenever the sample spout comes in line with the ore stream, the ore passes through the plate and into the sample; at all other times the ore is deflected from the plate and drops into the reject. Generally, the sampler makes from 10 to 30 rpm, and removes about 1/5 of the ore stream. Newton, 1; Newton, 2 soaking a. A phase of a heating operation during which metal is maintained at the requisite temperature until the temperature is uniform throughout the mass. CTD b. Prolonged holding at a selected temperature. ASM, 1 soap earth See: steatite soaprock See: soapstone 2984

soapstone a. Massive talc. Syn: steatite; soaprock. b. A metamorphic rock of massive, schistose, or interlaced fibrous or flaky texture and soft, unctuous (greasy) feel; composed essentially of talc with variable amounts of mica, chlorite, amphibole, and pyroxene; alteration product of ultramafic rock; may be carved into art objects or sawn into dimension stone for use where chemical resistance or high heat capacity is needed. c. A miners' and drillers' term for any soft, unctuous rock. Syn: agalmatolite; Manchurian jade; talcum. d. See: saponite; talc. soapy feel Unctuous; said of talc and other magnesium minerals. Nelson soapy heads Eng. In stones, joints filled with saponaceous or talclike mineral. sobotkite An aluminum-rich variety of saponite(?). socket a. A device fastened to the end of a rope by means of which the rope may be attached to its load; the socket may be opened or closed. Zern b. In blasting, the hole left after firing. Pryor, 3 c. A hollow tool for grasping and lifting tools that have been dropped into a well boring. Standard, 2 d. The point in a borehole, usually in bedrock, at which the bottom end of a string of casing or drivepipe is set. Long e. To lower casing or drivepipe into, and seat it in, a borehole. Long f. An overshot. Long g. A fishing tool designed to encircle and grasp a cylindrical object. Long h. To spring a borehole. See also: camouflet i. See: bootleg soda a. The normal carbonate of sodium, Na2 CO3 , soda ash; the latter being the common name of the commercial product used in chemical industries. b. Sodium carbonate, Na2 CO3 ; esp. the decahydrate, Na2 CO3 .10H2 O. Loosely used for sodium oxide, sodium hydroxide, sodium bicarbonate, and even for sodium in informal expressions such as soda spar. A prefix added to the names of igneous rocks to indicate that they contain soda pyroxenes and/or soda amphiboles; e.g., soda rhyolite, soda trachyte, soda granite, etc. AGI c. A former name for natron. soda alum 2985

a. An alum of aluminum and sodium. Occurs in nature as the mineral mendozite. See also: mendozite b. See: sodium alum soda-and-cleanup man A laborer who sifts soda ash for use in refining copper. DOT soda ash Commercial term for sodium carbonate, Na2 CO3 . AGI soda feldspar A sodium-aluminum silicate occasionally used as a refractory raw material in the manufacture of porcelain enamels, giving a softer enamel when used to replace potash feldspar in equal weights. See also: albite Enam. Dict.; CTD soda hornblende See: arfvedsonite soda lakes a. Salt lakes, the water of which contains a high content of sodium salts (chiefly chloride, sulfate, and acid carbonate). These salts also occur as an efflorescence around the lakes. CMD b. For soda lakes where the water has evaporated leaving behind evaporite salts, the term "dry soda lakes" may be used. soda lime a. A granular mixture of calcium hydroxide with sodium hydroxide, or potassium hydroxide, or both, and sometimes with other substances (such as kieselguhr). Used to absorb moisture and acid gases, esp. carbon dioxide, as in gas masks. b. Can refer to a type of glass container in which the principal ingredients are soda ash and lime. soda-lime sinter process Process for recovering alumina from red mud by mixing it with soda ash (Na2 CO3 ) and ground limestone, and sintering in a rotary kiln at temperatures of 1,800 to 2,000 degrees F (980 to 1,090 degrees C). This breaks up the sodium aluminum silicate and forms an insoluble calcium silicate and sodium aluminate. The sinter is leached with water to recover the sodium silicate, which is then treated in the same way as in the standard Bayer process. Newton, 1 sodalite 2986

a. An isometric mineral, Na8 Al6 Si6 O24 Cl2 ; sodalite group; typically blue or blueviolet; in various sodium-rich igneous rocks. b. The mineral group hauyne, lazurite, nosean, and sodalite. sodalitite An urtite composed chiefly of sodalite, with smaller amounts of acmite, eudialyte, and alkali feldspar. AGI soda mica See: paragonite soda microcline A microcline in which sodium replaces potassium. Dana, 4 soda niter See: nitratine; sodium nitrate. soda nitrate NaNO3 , widely used as a fluxing raw material in enamels, usually in conjunction with soda ash. A small percentage is beneficial in oxidizing any organic impurities. Also called Chile nitre; saltpeter. Syn: sodium nitrate soda orthoclase Apparently monosymmetric feldspars with a notable amount of soda may be called soda orthoclase. When the soda equals or exceeds the potash, the crystals exhibit triclinic symmetry and are soda microcline. Spencer, 5 soda prairie An extensive level barren tract of land covered with a whitish efflorescence of sodium carbonate (natron), as in parts of southwestern and western United States and Mexico. Syn: salt prairie soda richterite To replace the name astochite. See also: astochite soda spar 2987

An informal term for sodic feldspar, i.e. albite, or for a feldspar mixture assaying at least 7% Na2 O. Syn: Na-spar CF: potash spar soddyite An orthorhombic mineral, (UO2 )2 SiO4 .2H2 O ; pale yellow; in pegmatites with malachite, in fissure fillings with curite and sklodowskite. Also spelled soddite. Soderberg anode A continuously formed anode for aluminum production in which the mixture of petroleum coke and coal-tar pitch is continuously added to a steel casing and is baked as it passes through the heated casing, such that the baked anode emerging into the cell continuously replaces the anode being consumed. Soderberg electrode A continuously formed electrode used in a metallurgical electrical furnace, in which a mixture of petroleum coke and coal-tar pitch is continuously added to a steel casing and is baked as it passes through the heated casing, such that the baked electrode emerging into the furnace continuously replaces the electrode being consumed; e.g., used in aluminum and ferroalloy production; may be oriented either vertically or horizontally. sodium a. A soft, bright, silvery metallic element; one of the alkali metals. Symbol, Na. It is a very reactive element and is never found free in nature. The most common compound is sodium chloride. Sodium compounds are important to the paper, glass, soap, textile, petroleum, chemical, and metal industries. Metallic sodium should be handled with great care; it should be kept in an inert atmosphere and contact with water avoided. Handbook of Chemistry and Physics, 3 b. For some minerals with the "sodium" prefix, search under the root mineral name. sodium alum An isometric mineral, NaAl(SO4 )2 .12H2 O . Syn: soda alum sodium arc light See: sodium light sodium autunite A tetragonal mineral, Na2 (UO2 )(PO4 )2 .8H2 O ; meta-autunite group; radioactive; yellow. 2988

sodium bentonite See: Wyoming bentonite sodium-calcium feldspar See: plagioclase sodium ethylxanthate Pale green; NaC2 H5 OCSS ; molecular weight, 144.19; and soluble in water and in ethyl alcohol. An ore-flotation agent. Bennett; Handbook of Chemistry and Physics, 2 sodium feldspar See: albite sodium hydroxide See: caustic soda sodium illite A sodium-rich illite. See: brammallite sodium light Yellow light emitted by the glowing vapor of sodium, consisting of the D lines of sodium at wavelengths 5,890 Aa and 5,896 Aa; produced by special lamps and filters. Syn: sodium vapor light; sodium arc light. sodium niobate NaNbO3 ; a compound believed to be ferro-electric and having potential use as a special electroceramic. The Curie temperature is 360 degrees C. Dodd sodium nitrate Colorless; transparent; odorless; hexagonal; NaNO3 ; molecular weight, 84.99; slightly bitter taste; sp gr, 2.267; melting point, 308 degrees C; no boiling point because it decomposes at 380 degrees C; soluble in water, in ethyl alcohol, and in methyl alcohol; very soluble in ammonia; only slightly soluble in acetone; and slightly soluble in glycerol. Used as an oxidizer in solid rocket propellants, a flux, in glass manufacture, in military explosives, and in enamel for pottery. Also used in enamel frit batches to prevent reduction of any easily reducible ingredients, such as lead oxide. The function of 2989

sodium nitrate, when used in glass batches, is to oxidize organic matter and to prevent reduction of some of the batch constituents. Syn: soda niter See also: soda nitrate CCD, 2; Handbook of Chemistry and Physics, 2; Lee sodium nitrate gelignites These explosives are sometimes referred to as straight gelatins. They are really modifications of blasting gelatin in which varying percentages of nitroglycerin are replaced by sodium nitrate and combustible material to give a range of gelatinous explosives of varying strengths. The nitroglycerin content may be from about 30% to 80%. Straight gelatins are characterized by their plastic consistency; high densities of 1.5 to 1.6 g/cm3 ; medium velocity of detonation of 2,500 m/s; good resistance to the effects of water, which also gives them good storage properties, and they possess fume characteristics suitable for underground workings. All the various requirements for metal mining, tunneling, and quarrying operations are covered by this wide range of gelatinous explosives. Their high resistance to water makes them particularly useful in wet conditions, and their relatively high density is advantageous where a powerful concentration of explosive energy is required. McAdam, 2 sodium regulations A permit, not including more than 2,560 acres (1,037 ha) in one State, is granted to prospect for chlorides, sulfates, carbonates, borates, silicates, or nitrates of sodium, and the royalty and rentals are similar to those for potash. Where necessary to secure the most economical mining, a person, association, or corporation may be permitted to hold up to 15,360 acres (6,221 ha) in one State. Lewis sodium sesquicarbonate Colorless, gray, or yellowish-white; monoclinic; Na3 (CO3 )(HCO3 ).2H2 O ; mol wt, 226.03; sp gr, 2.112, but ranges from 2.11 to 2.147 in the mineral; Mohs hardness, 2.5 to 3.0; soluble in water. Extensive deposits of sodium sesquicarbonate, variously known as the mineral natrona, trona, or urao, occur in California and Wyoming; in Hungary and Egypt; and in the deserts of Africa, Asia, and South America. Syn: natrona; trona; urao. Handbook of Chemistry and Physics, 2; CCD, 2 sodium tannate Sometimes used as a deflocculant for clay slips; the effect is marked, only a small proportion being required. The material used for this purpose is generally prepared from NaOH and tannic acid; the former should be in excess and the pH should be about 8 to 9. Dodd sodium tantalate 2990

NaTaO3 ; a ferro-electric compound having the ilmenite structure at room temperature; the Curie temperature is approx. 475 degrees C. Of potential interest as a special electroceramic. Dodd sodium uranate Na2 (UO2 )2 (ASO4 )2 .8H2 O ; has been used as a source of uranium for uranium red. Dodd sodium uranospinite A tetragonal mineral, (Na2 ,Ca)(UO2 )2 (AsO4 )2 .5H2 O ; meta-autunite group; radioactive; yellow-green to yellow; forms fine, tabular to elongated crystals or radial fibrous aggregates; in the oxidation zone of primary hydrothermal deposits. It is the most abundant secondary uranium mineral. sodium vanadate NaVO3 ; a ferro-electric compound having potential use as a special electroceramic. The Curie temperature is approx. 330 degrees C. Dodd sodium vapor light See: sodium light sodium xanthate a. Yellowish; amorphous; NaS.CS.OC2 H5 ; molecular weight, 144.19; and soluble in water and in ethyl alcohol. Used as a flotation agent. Bennett; Handbook of Chemistry and Physics, 2 b. See: sodium ethylxanthate soffioni An emanation, from the Earth, of vapors that are principally boric acid; also, the opening from which the vapors issue. See also: solfatara; fumarole; mofette. soft a. Bituminous as opposed to anthracite coal. b. In mineralogy, usually refers to minerals readily scratched by a needle or knife blade. Hess c. Tender, friable, or full of slips and joints. d. As applied to a glass or glaze, refers to a low softening temperature; such a glass or glaze, when cold, is also likely to be relatively soft; i.e., of lower than average hardness, in the normal sense. Dodd soft coal 2991

Bituminous coal as opposed to anthracite. See also: bituminous coal Fay soften To heat ore so that the minerals are cracked and fissured, permitting easier crushing. Fay softening a. Treatment in which metal is heated below its critical point and then slowly cooled. Pryor, 3 b. Of lead, the removal of antimony and other impurities. Fay softening point a. Certain materials do not have a definite melting point but soften over a range of temperatures. In certain refractory substances, the softening point is measured as the pyrometric cone equivalent (PCE), which is the number of that standard pyrometric cone whose tip would touch the supporting plaque simultaneously with a cone of the refractory material being investigated. b. When referring to glass, the temperature at which the viscosity is 10 7.6 P (100.6 MPa.s); this viscosity corresponds to the temperature at which tubes, for example, can be conveniently bent. Also known as the 7.6 temperature; Littleton softening point. Dodd soft formation See: soft ground soft ground a. That part of a mineral deposit that can be mined without drilling and shooting. It is commonly the upper, weathered portion of the deposit. AGI b. Heavy ground. Rock about underground openings that does not stand well and requires timbering. soft-ground boring tool Drilling tool used in soft ground, such as overburden, clay, soft shale, etc. Long soft inclusion Applied in the grading of quartz crystals to feathery or fernlike types of foreign inclusions, which look soft (no implication of physical hardness). Am. Mineral., 2 soft iron Iron which can be worked with ordinary cutting tools or which can be readily abraded with files. It is darker gray in color than the harder cast iron. Crispin 2992

soft mica Mica which, when slightly flexed or distorted with thumb pressure, generally shows a tendency toward delamination. Such mica, in thick pieces, generally gives a dull sound when tapped against a hard surface. Skow softness Tendency to deform easily. It is indicated in a tensile test by low ultimate tensile stress and large reduction in area. Usually the elongation is also high. In a notched bar test, specimens bend instead of fracturing, and energy absorbed is relatively small. See also: toughness; brittleness. CTD soft ore A term used in the Lake Superior region for an earthy, incoherent iron ore mainly composed of hematite or limonite (goethite) and containing 45% to 60% iron. AGI soft phosphate A term which is applied arbitrarily to anything phosphatic that is not distinctly hard rock. soft radiation Ionizing radiation of long wavelength and low penetration. NCB soft rock a. A term used loosely for sedimentary rock, as distinguished from igneous or metamorphic rock. AGI b. Rock that can be removed by air-driven hammers, but cannot be handled economically by pick. CF: hard rock soft-rock geology A colloquial term for geology of sedimentary rocks, as opposed to hardrock geology. AGI soft skin A soft outer skin developed on burned diamonds. Long soft steel A general term applied to steels of low carbon content that do not temper. See also: mild steel 2993

soft vector A plane or direction in a diamond or other mineral having less resistance to abrasion than that of the hard-vector planes. CF: hard vector Long soft water Water free from calcium carbonate and calcium sulfate. CF: hard water; hardness. Crispin soil a. All unconsolidated materials above bedrock. This is the meaning of the term as used by early geologists and in some recent geologic reports, and has been vigorously advocated by Legget (1967, 1973). It is the common usage among engineering geologists (see, e.g., compaction; soil mechanics). In recent years the approx. syn. regolith has come into wide geological use. AGI b. The natural medium for growth of land plants.--Etymol: Latin solum, ground. See also: sounding soil analysis See: soil survey soil catena A related sequence of soil profile types created by changes from one drainage condition to another. These changes are usually transitional. Hawkes, 2 soil cement The addition of cement to a soil, as a binding agent, and converting it into a weak form of concrete. See also: cement stabilization Nelson soil classification tests The tests are of two main types, namely: (1) mechanical analysis, performed by sieving or sedimentation, to determine the size-distribution of the constituent particles; and (2) index property tests, for soils passing a 36-mesh British Standard sieve, by means of which the type is deduced from the moisture content at standard consistencies. See also: index properties soil core A cylindrical sample of soil for tests and examination. Undisturbed samples may be obtained by the use of special appliances, which allow extraction of soil cores of 2994

diameter usually 1-1/2 in (3.8 cm) or 4 in (10.2 cm). The core barrel, forming part of the coring tool, is detachable and is capped and the core hermetically sealed for delivery to the laboratory. The natural moisture content and other properties are preserved for examination. Individual soil cores, up to 3 ft (0.9 m) in length, may be obtained by continuous coring if necessary. See also: borehole samples; undisturbed sample. Nelson soil creep The gradual, steady downhill movement of soil and loose rock material on a slope that may be very gentle but is usually steep. Syn: surficial creep soil flow See: solifluction soil fluction See: solifluction soil formation The processes whereby fragmental material resulting from rock weathering is transformed into a medium that can support plant growth. soil-forming factors Factors, such as parent material, climate, vegetation, topography, organisms, and time, involved in the transformation of an original geologic deposit into a soil profile. ASCE soil horizon A layer of a soil that is distinguishable from adjacent layers by characteristic physical properties, such as structure, color, or texture, or by chemical composition, including content of organic matter or degree of acidity or alkalinity. Soil horizons are generally designated by a capital letter, with or without a numerical annotation, e.g. A horizon, A2 horizon. Syn: horizon; soil zone; pedologic horizon. AGI soil mechanics The application of the principles of mechanics and hydraulics to engineering problems dealing with the behavior and nature of soils, sediments, and other unconsolidated accumulations of solid particles; the detailed and systematic study of the physical properties and utilization of soils, esp. in relation to highway and foundation engineering and to the study of other problems relating to soil stability. AGI 2995

soil penetrometer A sounding instrument, which may be used to supplement the vane test. It consists essentially of a rod inside a tube. When the appliance is mechanically jacked into the ground, the point or cone of the rod records all differences in resistance to penetration. It thus determines quickly the soil strength profile in depth and detects any soft beds in advance of the vane tests. See also: penetration log soil physics The organized body of knowledge concerned with the physical characteristics of soil and with the methods employed in their determinations. ASCE soil profile A vertical section of a soil that displays all its horizons. Syn: profile soil sampler a. A tube driven into the ground so as to obtain an undisturbed soil sample. In sands, such tubes would be fitted with a core catcher. Hammond b. One of a number of different mechanical devices used for taking samples of an unconsolidated material. See also: solid-barrel sampler; split-tube barrel; split-tube sampler. Long soil science The study of the properties, occurrence, and management of soil as a natural resource. Generally it includes the chemistry, microbiology, physics, morphology, and mineralogy of soils, as well as their genesis and classification. Syn: pedology soil shredder A machine employed in soil stabilization comprising two nearly touching half drums, which rotate in opposite directions and break up the soil. Hammond soil stabilization Chemical or mechanical treatment designed to increase or maintain the stability of a mass of soil or otherwise to improve its engineering properties. See also: cementmodified soil; cement stabilization; processing; pulverization. ASCE soil structure The arrangement and state of aggregation of soil particles in a soil mass. See also: flocculent structure; honeycomb structure; single-grained structure. ASCE 2996

soil survey a. A detailed investigation of the soils at a site, including boreholes and tests to determine their nature, thickness, strength, and depth to bedrock. See also: site investigation; soil mechanics. b. Geochemical prospecting term for the chemical analysis of systematically collected samples of soil and weathered rock. soil test The laboratory procedure followed in examining and determining the physical characteristics of a soil sample. Long soil zone See: soil horizon Soisson Rodange process A process for the manufacture of high-quality killed basic Bessemer steel in which the steel, after dephosphorization, is poured into another ladle containing the solid components of a basic oxidizing and fluid slag. Blowing for 30 to 40 s generates sufficient heat to promote mixing and to avoid skull. Phosphorus contents are readily lowered and high-quality killed steel is produced with low additional cost. Osborne sol a. A homogeneous suspension or dispersion of colloidal matter in a fluid (liquid or gas). AGI b. A completely mobile mud. A sol is in a more fluid form than a gel. AGI solar a. A platform in a Cornish Mine shaft and esp. between a series of ladders; a longitudinal partition forming an air passage between itself and the roof in a mine. Usually spelled sollar or soller. See also: sollar b. A colloquialism used by surveyors to mean an observation on the sun. solar salt Salt obtained by solar evaporation of seawater or other brine in shallow lagoons or ponds. solder a. To unite the surfaces of metals. Nelson b. An alloy of uniting metals. Brazing solders are alloys of zinc and copper, while soft solders are alloys of tin and lead Nelson 2997

soldier frame Frame set into the inside of a shaft prior to breaking through for a heading. Stauffer sole a. The under surface of a rock body or vein, esp. the bottom of a sedimentary stratum. AGI b. The fault plane underlying a thrust sheet. AGI c. The middle and lower parts of the shear surface of a landslide. AGI d. The major fault plane over which other beds ride forward as a group during distributive faulting. e. The lowest thrust plane in an area of overthrusting. Commonly rocks above are imbricated. AGI f. The bottom of a level. Solenhofen stone A lithographic limestone of Late Jurassic age found at Solenhofen (Solnhofen), a village in Bavaria, West Germany. It is evenly and thinly stratified and contains little clays. See also: lithographic limestone AGI solfatara A type of fumarole, the gases of which are characteristically sulfurous. Etymol: the Solfatara volcano, Italy. AGI solfataric Applied to a dormant or decadent stage of volcanic activity characterized by the emission at the surface of gases and vapors of volatile substances. solid a. Coal that has not been undermined, shear cut, or otherwise prepared for blasting. Used in the expression, "shooting off the solid." Fay b. That part of the coal that cannot be thrown out by a single shot, or the coal beyond the loose end. Used in expressions describing holes drilled for blasting, such as "three feet into the solid," or "on the solid." Fay c. Unmined; ungot. Mason d. A rock having few open cracks, crevices, or joints and relatively unaffected by the weakening effects of weathering. Long e. A diamond free of cracks discernible by eye. Long f. The rock near underground openings that stands well without artificial support. Long solid-barrel sampler A straight-walled cylinder with or without a valve on the bottom. Used for taking soil samples. CF: soil sampler; split-tube sampler. Long solid bearing 2998

A one-piece bushing. Nichols, 1 solid bit See: noncoring bit solid bituminous material Material having a penetration at 77 degrees F (25 degrees C), under a load of 100 g applied for 5 to 10 s. Urquhart solid car A mine car equipped with a swivel coupling and generally used with a rotary dump. One or more cars are pulled into the rotary dump, which turns through 180 degrees and the coal is emptied out. See also: mine car Kentucky solid couplings Generally of either the flanged-face or the compression type. They are used to connect two shafts to make a permanent joint and usually are designed to be capable of transmitting the full load capacity of the shaft. This coupling has no flexibility, either torsional, angular, or axial, hence it is limited to those installations where rigid connections are suitable, particularly in line shafts and extension shafts. Pit and Quarry solid crib timbering Shaft timbering with cribs laid solidly upon one another. solid-crown bit See: noncoring bit solid-drawn Drawn from hollow ingots, or otherwise, on mandrels of successively decreasing diameters; said of certain seamless metal tubes. Standard, 2 solid drilling In diamond drilling, using a bit that grinds the whole face, without preserving a core for sampling. Nichols, 1 solid explosives 2999

These explosives are employed to a certain extent in the form of a powder in cartridges, or as a light-running granulated mass, or as solid sticks. They have the disadvantage that the density of charging will be small, which means that the cost of drilling will be comparatively high. Fraenkel solid fuels Any fuel that is a solid; such as wood, peat, lignite, bituminous, and anthracite coals of the natural variety and the prepared varieties such as, pulverized coal, briquettes, charcoal, and coke. Divided into two broad classes: naturally occurring and manufactured. Newton, 1 solidification range Temperature range over which mixtures (alloys, fluxes) melt. In a constitutional diagram, the area between liquidus and solidus. Pryor, 3 solidification shrinkage The decrease in volume of a metal during solidification. ASM, 1 solid loading Filling a drill hole with all the explosive that can be crammed into it, except for stemming space at top. Nichols, 1 solid map Gr. Brit. A geological map showing the extent of solid rock, on the assumption that all surficial deposits, other than alluvium, are absent or removed. AGI solid packing See: solid stowing solid road Any roadway driven through the solid coal seam with rib sides. See also: narrow stall; narrow work. Nelson solid rock Gr. Brit. Bedrock. AGI solids handling pump 3000

Usually a centrifugal pump designed to resist abrasion and used for pumping sand, gravel, fine coal, and ore tailings. Rubber linings are generally used, which last longer than steel or iron. See also: pulsometer solid smokeless fuel A solid fuel, such as coke, which produces comparatively no smoke when burned in an open grate. See also: anthracite; briquette; coke. Nelson solid solubility The extent to which one metal is capable of forming solid solutions with another. This varies widely between different pairs of metals, some of which are mutually soluble in all proportions, while others are practically insoluble in each other. CTD solid solution a. A single crystalline phase that may be varied in composition within finite limits without the appearance of an additional phase. Syn: mix-crystal; mixed crystal. AGI b. Partial or total miscibility between two or more crystal structures; e.g., ionic substitution. Syn: crystal solution CF: isomorphous mixture; isomorphous series. solid stowing The complete filling of the waste area behind a longwall face with stone and dirt. The packing operation may be by hand or mechanical methods, e.g., pneumatic stowing. See also: double packing; stowing method; strip packing. Nelson solidus On a temperature-composition diagram, the locus of points in a system at temperatures above which solid and liquid are in equilibrium and below which the system is completely solid. In binary systems without solid solutions, it is a straight line; in binary systems with solid solutions, it is a curved line or a combination of straight and curved lines; in ternary systems, it is a flat plane or a curved surface. AGI solid web The web of a steel beam consisting of a rolled section or a plate as distinct from a lattice. Hammond solid woven conveyor belt A construction of conveyor belt consisting of multiple plies of fabrics woven into one piece, which is done on looms designed for this purpose. Stripes are woven into the belt 3001

to show the number of plies, which range from 2 to 10. Impregnating and coating treatments are frequently employed. solifluction The slow, viscous downslope flow of waterlogged soil and other surficial material, normally at 0.5 to 5.0 cm/yr; esp. the flow occurring at high elevations in regions underlain by frozen ground (not necessarily permafrost) that acts as a downward barrier to water percolation, initiated by frost action and augmented by meltwater resulting from alternate freezing and thawing of snow and ground ice. The term has been extended to include similar movement in temperate and tropical regions; also, it has been used as a syn. of soil creep, although solifluction is generally more rapid. It is preferable to restrict the term to slow soil movement in periglacial areas. Also spelled solifluxion. Syn: soil flow; soil fluction; sludging. AGI sollar a. Landing stage in a mine shaft. Also spelled soller; solar. Pryor, 3 b. A timber staging, alongside a haulage level, for piling ore ready for loading into mine cars. Nelson c. A staging between ladderway sections in a shaft. Nelson d. The plank flooring of a gallery covering a gutterway beneath. e. A longitudinal partition forming an air passage between itself and the roof in a mine working. Webster 3rd f. A platform from which trammers shovel or throw the ore or rock into a car. g. A wooden platform fixed in a shaft for ladders to rest on. See also: air sollar soller See: sollar solonetz soil A soil occurring most commonly under arid conditions, but may also be found in semiarid and subhumid regions. Usually found in depressions where it has originated by evaporation under shallow ground-water conditions. Characterized by sodium carbonate as the predominant salt and a dark-colored B horizon, which is strongly alkaline in reaction. Hawkes, 2 solubility a. The extent that one material will dissolve in another, generally expressed as mass percent, or as volume percent or parts per 100 parts of solvent by mass or volume. The temperature should be specified. ASTM b. The weight of a dissolved substance that will saturate 100 g of a solvent. CTD c. Concentration of a substance in a saturated solution; i.e., in equilibrium between dissolved and undissolved phases at given temperature. Pryor, 3 3002

solubility product concentration In a saturated solution of an electrovalent compound having limited solubility, the product of the ionic concentrations, at the exponential value shown in the stoichiometric equation for its dissociation, is constant at a given temperature. Pryor, 3 soluble Capable of being dissolved in a fluid. Crispin soluble anode An anode that goes into solution during an electrolytic process. Osborne soluble glass Solid sodium silicate or potassium silicate. Syn: water glass CTD solute a. The substance dissolved in a solution, as distinguished from the solvent. Standard, 2 b. A substance dissolved in a liquid. solution A substance that is a homogeneous mixture and has a continuous variation of composition up to a solubility limit. solution breccia A collapse breccia formed where soluble material has been partly or wholly removed by solution, thereby allowing the overlying rock to settle and become fragmented; e.g. a breccia consisting of chert fragments gathered from a limestone whose carbonate material has been dissolved away. See also: evaporite-solution breccia AGI solution cavity A cavity formed in certain rocks in which percolating sollutions have filled with valuable minerals; cavities formed in certain rocks, such as limestones, where portions have been dissolved by percolating waters. See also: mineralization solution injection Artificial cementing of loose soils or strata to increase their load-bearing capacity. Hammond 3003

solution mining a. The in-place dissolution of water-soluble mineral components of an ore deposit by permitting a leaching solution, usually aqueous, to trickle downward through the fractured ore to collection galleries at depth. It is a type of chemical mining. CF: in situ leaching b. The mining of soluble rock material, esp. salt, from underground deposits by pumping water down wells into contact with the deposit and removing the artificial brine thus created. AGI c. Hydrometallurgical treatment of ore for recovery of the mineral values at the mine site, in conjunction with conventional open pit or underground mining procedures. See also: surface leaching solution pipe A vertical cylindrical hole, formed by solution and often without surface expression, that is filled with detrital matter. AGI solution plane A crystallographic direction of chemical solubility in a crystal, possibly due to exsolution of a second crystalline phase on falling temperature and/or pressure or to unannealed slip during plastic deformation. Solution planes may lead to parting in some mineral specimens. solution ripple See: scallop solution subsidence Gradual subsidence of nonsoluble strata due to the solution of underlying rock. AGI solvate A chemical compound consisting of a dissolved substance and its solvent, e.g. hydrated calcium sulfate. AGI Solvay process Manufacture of sodium carbonate or soda ash, Na2 CO3 from salt (sodium chloride), ammonia, carbon dioxide, and limestone by a sequence of reactions involving recovery and reuse of practically all the ammonia and part of the carbon dioxide. Limestone is calcined to quicklime and carbon dioxide. The carbon dioxide is dissolved in water containing the ammonia and salt, with resulting precipitation of sodium bicarbonate. This is separated by filtration, dried, and heated to form sodium carbonate. The liquor 3004

from the bicarbonate filtration is heated and treated with lime to regenerate the ammonia. Calcium chloride is a major byproduct. CCD, 2 solvent a. A substance used to dissolve another substance. Crispin b. That component of a solution that is present in excess; or the physical state of which is the same as that of the solution. CTD solvent extraction a. A method of separating one or more substances from a mixture, by treating a solution of the mixture with a solvent that will dissolve the required substances, leaving the others. Hammond b. A process in which one or more components are removed from a liquid mixture by intimate contact with a second liquid, which is itself nearly insoluble in the first liquid and dissolves the impurities and not the substance that is to be purified. Syn: liquid-liquid extraction CCD, 2 sonar The method or equipment for determining, by underwater sound, the presence, location, or nature of objects in the sea. The word sonar is an acronym derived from the expression SOund NAvigation and Ranging. Hunt sonar boomer seismic system A complete continuous seismic profiling system consists of the boomer unit, sonar recorder, transducer fish, receiving hydrophone, preamplifier, if necessary, and variable filter. Sonar boomer units are available from 1000 W-second models up to 13,000 Wsecond (experimental models). The standard boomer consists of a power supply, capacitor bank and transducer. Boomers are used for marine geological studies and dredging surveys. The power supply output is fed to the capacitor bank, which is discharged into the transducer producing a precisely repeatable pressure pulse in the water. Hunt sondalite A metamorphic rock composed of cordierite, quartz, garnet, tourmaline, and kyanite. Holmes, 2 sonde The elongate cylindrical tool assembly used in a borehole to acquire a well log. It contains various energy-input devices and/or response sensors. The sonde is lowered into the borehole by a multi-conductor cable, or wire line. AGI 3005

sonic drilling Core drilling through high-powered vibrations transmitted down the drill casing to a cutting shoe. The casing and the shoe vibrate into the ground and through the rock, resulting in an undisturbed core of unconsolidated material. SME, 1 sonic gage See: acoustic-strain gage sonic log An "acoustic log" showing the interval-transit time of compressional seismic waves in rocks near the well bore of a liquid-filled borehole. Used chiefly for estimating porosity and lithology. sonic method A method of measuring underground rock pressure by determining the velocity of sound through the rock. Sonic velocity is a function of the elastic modulus of the rock traversed by the wave, and this, in turn, is a function of the pressure. A hammer blow on the rock face is used to initiate the sound waves, which are picked up by a microphone placed at the site of the blow and by a second microphone at the other end of the path through the rock under test. The difference between the times of the signals received from the two microphones will equal the time taken by the sonic pulse to pass through the rock. The signals are converted into visible waveforms on the screen of an oscillograph, and these are photographed or otherwise recorded to form a permanent record. Issacson sonic pile driver A driver based on the principle of delivering vertical vibrations to the head of a pile in alternating up and down cycles at a rate of 100 Hz. These vibrations set up highamplitude waves of tension and compression in the pile, producing alternate expansion and contraction in minute amounts. The elongation of the pile in expansion displaces the soil at the pile tip, and the weight of the pile, hammer, and added loads shoves the pile into the miniscule void. Since this action is occurring at the rate of 100 Hz, the individual movements need not be of great magnitude to produce rapid penetration of the pile. Carson, 2 sonigage An ultrasonic testing instrument used primarily for the measurement of the thickness of materials. Osborne sonims 3006

Solid, nonmetallic inclusions in metal. Henderson soniscope An inspection instrument, which sends, by electronic means, pulses of high frequency through the material to be tested and measures the time of travel from the transmitter on one face to the receiver on the distant face of the material. This method of inspection is known as pulse testing. Osborne sonograph Seismograph developed by Frank Rieber for the application of reflection methods to areas of complex geology and steeply dipping beds. The ordinary oscillograph traces are replaced by sound tracks of variable transparency on a moving picture film. The analyzer adds up impulses which are in phase while the random effects tend to cancel one another. AGI sonolite A monoclinic mineral, Mn9 (SiO4 )(OH,F)2 ; humite group; dimorphous with jerrygibbsite; red-orange. sonometer An instrument for measuring rock stress. Piano wire is tuned between two bolts cemented into drill holes in the rock, and a change of pitch after destressing is observed and used to indicate stress. Pryor, 3 sonoprobe A type of echo sounder that generates sound waves and records their reflections. It is used in subbottom profiling. AGI Sonstadt solution A solution of mercuric iodide in potassium iodide with a density of 3.2 g/cm3 and used as a "heavy liquid." CF: bromoform; Klein solution; methylene iodide; Clerici solution. Syn: Thoulet solution soot A black substance, consisting essentially of carbon from the smoke of wood or coal, esp. that which adheres to the inside of the chimney, containing also volatile products condensed from the combustion of the wood or coal, including certain ammonia salts. Standard, 2 3007

sooty chalcocite A black, pulverent variety of chalcocite of supergene origin. sooty streamers Fine and often unburned dust settling out in steamy, warm conditions in stagnant situations. Sinclair, 1 sop a. Cumb. A hematite iron-orebody of circular or oval plan and conical section, formed in a swallow hole. Arkell b. Cumb. A nest or pocket of black lead. Arkell Sophia-Jacoba process See: Barvoys process sopwith staff A telescopic self-reading staff dividing into three sections, set one above the other when the staff is at its full extent of 14 ft (4.3 m). Graduations are marked in feet, tenths and hundredths of a foot, and the thickness of the horizontal lines is 0.01 ft (3.05 mm), alternately black and white. Hammond sordavalite An old name for the glassy salbands of small, diabase dikes formerly regarded as a mineral. It is derived from Sordavala, Finland. Sorel cement Calcined magnesite or magnesia mixed with a solution of magnesium chloride. It sets to a hard mass within a few hours. The basis of artificial flooring cements. CTD sorelslag A titanium slag containing about 80% TiO2 . It is made by electric-furnace smelting of iron-titanium ores. Newton, 1 Soret's principle If differences of temperature are induced in a solution of sodium chloride or some other substance in water, the dissolved material will become relatively more concentrated in those portions in which the temperature is lowest. Fay 3008

soroche A mountain sickness that attacks miners who are newcomers in high altitudes. Symptoms are headaches, nausea, vomiting, and nosebleed. If the symptoms do not soon pass, there is nothing to be done except return to a lower altitude. Hoover sorption Any type of retention of a material at a surface, esp. when the mechanism is not specified. Adsorption is then restricted to the physical process that leads to the formation of a unimolecular surface layer; chemisorption refers to the corresponding chemical process; and absorption to the entrance of the sorbed material within the solid. Miall sorted See: graded sorting a. In a genetic sense, it may be applied to the dynamic process by which granular or fragmental material having some particular characteristic, such as similar size, shape, specific gravity, or hydraulic value, is selected from a larger heterogeneous mass. b. The degree of similarity, in respect to some particular characteristic, of the component parts in a mass of material. c. A measure of the spread of a distribution on either side of an average. d. The separation of coal or ore as mined into valuable material and waste. e. See: handpicking sorting coefficient a. A coefficient used in describing the distribution of grain sizes in a sample of unconsolidated material. It is defined as S0 = Q1 /Q3 , where Q1 is the diameter that has 75% of the cumulative size-frequency (by weight) distribution smaller than itself and 25% larger than itself, and Q3 is that diameter having 25% of the distribution smaller and 75% larger than itself. Hunt b. Dimensionless measure for degree of sorting. Schieferdecker soude emerald See: emerald triplet sound a. The act of striking a mine roof with a metal testing bar to ascertain whether or not it is strong and safe. Hudson b. A dam or barrier in a mine in which the frictional resistance to the passage of water is high. Such a dam permits little water to pass through it and is 3009

said to be "sound." Sinclair, 4 c. Elastic waves in which the direction of particle motion is longitudinal; i.e., parallel with the direction of propagation. The term is sometimes restricted to such waves in gases, particularly air, and in liquids, particularly water, but it is also applied to wave motion in solids. It is the type of wave motion most often used in reflection-seismic exploration. AGI sound channel Sound waves in the surface layers of the ocean tend to be refracted downward due to decrease of temperature with depth. In deep waters the sound waves are refracted upward by high and increasing pressure, which has a greater influence on the resulting refractive index of these layers than the decreasing temperature. The result is the formation at mid-depth of a wave guide that permits compressional waves of acoustic frequencies to travel great distances. Hy sounding a. See: roof testing b. Rapping on a pillar to signal a person on the other side or to enable the person to estimate its width. c. A rough method of judging by sound the direction and distance apart of two roadways driven in coal to meet each other. The sounding is made by giving two slow and three sharp knocks on the solid coal, which is answered in similar manner from the opposite roadway. The method is sometimes called chap. Nelson d. Subsurface investigation by observing the penetration resistance of the subsurface material without drilling holes. This can be done by driving a rod into the ground or by using a penetrometer. See also: penetrometer; soil. Long sounding lead In measuring water depth, the hand lead used in sounding. See also: hand lead sounding rod A closed pipe, 1 in (2.5 cm) in diameter, with a flush point and a driving tip, used in sounding. See also: sounding sounding the top Tapping the roof with a pick or bar to test its soundness. Korson sound intensity In a specified direction at any point, the average rate of sound energy transmitted in the specified direction through a unit area normal to this direction at the point considered. Hy 3010

sound velocity The rate at which a sound wave travels through a medium. Velocity is equal to the square root of the bulk modulus divided by density. Hy sound wave a. Sometimes used interchangeably with shock wave; technically, a wave motion in the air which affects the human ear as sound. Owing to the reflection of waves from the various surfaces, the sound is more or less prolonged, and as it reaches a given point is really a series of vibrations. Rice, 2 b. The wave of compression emanating from any sound source. Since sound travels as a wave of compression it heats the water as it passes through a water mass. Density and compressibility thus influence the velocity of sound; increasing density due to temperature, salinity, and pressure changes increases the velocity. High frequency waves above 10,000 Hz have very short range because absorption is high. Low frequencies have greater range. See: longitudinal wave sour a. Having an acid or tart taste; applied to minerals having the taste of sulfuric acid. b. Said of crude oil or natural gas containing significant fractions of sulfur compounds. CF: sweet source a. In seismic prospecting either: (1) the point of origin or shot from which elastic waves are propagated, or (2) the formation, horizon, interface, or boundary at which a seismic wave is refracted and/or reflected and returned to the surface. In earthquake seismology, the point of origin of an earthquake. In neutron logging, the source of neutrons at one end of the logging tool. AGI b. A radioactive material packaged to produce radiation for experimental or industrial use. Lyman c. The point of origin or procurement. Webster 3rd source area The area from which the sedimentary material is derived. source-receiver product In seismic prospecting, the product of the number of detectors per trace and the number of sources used simultaneously. AGI source rock The geological formation in which oil, gas, and/or other minerals originate. AGI 3011

sourdough a. Old-fashioned and seasoned prospector. Pryor, 3 b. A miner who has lived in Alaska more than one season. von Bernewitz sour gas Slang for either natural gas or a gasoline contaminated with odor-causing sulfur compounds. In natural gas the contaminant is usually hydrogen sulfide, which can be removed by passing the gas mixture through carbonate solutions containing special metal or organic activators. In gasolines, the sour contaminents are usually mercaptans, which are removed in the doctor treatment or by ethylene oxide with a phenolic catalyst. The improved gas or gasoline is known as sweet gas. CCD, 2 souring a. An alternative term for aging. See also: aging b. The storage for a short time of the moistened batch for making basic refractories; some magnesium hydroxide is formed and this acts as a temporary bond after the bricks have been shaped and dried. If souring is allowed to proceed too far, cracking of the bricks is likely during drying and the initial stages of firing. The high pressure exerted by modern brick presses generally gives sufficient dry strength without the bricks being soured, and souring is therefore now generally omitted. Dodd South African diamond Whole-stone diamonds having outside faces that are smooth as contrasted to the pebbly, encrusted surface of a Congo diamond; also applied to diamonds produced in South African mines as contrasted to those found in the Sierra Leone, Congo, Brazil, etc. Long southing A distance measured southwards from an east-west reference line. Hammond south-seeking pole See: north-seeking pole South Staffordshire method See: room-and-pillar southwestern cell

3012

Pneumatic flotation machine consisting of a long tank with V-shaped base into which pipes connected with a low-pressure source deliver compressed air. Internal baffles provide an air lift and the cell discharges a mineralized froth along one or both sides, the tailing leaving at the far end. The Britannia cell is a modified form. See also: Britannia cell Pryor, 3 souzalite A monoclinic mineral, (Mg,Fe)3 (Al,Fe)4 (PO4 )4 (OH)6 .2H2 O ; forms a series with gormanite; green. sovereign gold Standard 22 carat gold, containing 91.7% gold and 8.3% copper. Osborne soevite A carbonatite that contains calcite as a dominant phase. The name, given by Broegger in 1921, is for Soeve, Fen complex, Norway. AGI sow a. Mold of larger size than a pig. Webster 3rd b. A channel or runner that conducts molten metal to the rows of molds in a pig bed. Webster 3rd c. A mass of metal solidified in such a channel or mold. Webster 3rd d. An accretion that frequently forms in the hearth or crucible of a furnace; it consists mainly of iron. Also called salamander, bear, or shadrach. Fay Soxhlet thimble A dust-sampling instrument. The apparatus gives a gravimetric mass sample, with no information on the size distribution of the dust collected. Is useful where a sample is needed for determining mass concentration and for collecting dust for chemical, petrological, and X-ray analysis. See also: Hexhlet sampler; tyndallometer. Roberts, 1 spaad A fibrous talc. From the German spath. spaced loading a. Loading so that cartridges or groups of cartridges are separated by open spacers that do not prevent the concussion from one charge from reaching the next. Nichols, 1 b. See: deck loading 3013

space frame A three-dimensional frame that is stable against wind pressure without being braced against any other structure. Hammond space group In crystallography, any one of 230 independent combinations of the 14 essentially different kinds of three-dimensional periodicity (Bravais lattices) with other symmetry operations (point groups, screws, glides). CF: plane group; Bravais lattice; point group; screw; glide. space lattice a. A three-dimensional regularly repeating set of points so arranged as to determine sets of equally spaced parallel planes in various directions forming polyhedral cells (as in a honeycomb). Specif., a set of such points occupied by the atoms of a crystal. b. The pattern formed by the spatial distribution of atoms or radicals in a crystal. See also: crystal pattern; lattice. Hackh c. Any one of 14 infinite three-dimensional arrays of points such that each point is in an identical point environment. Syn: Bravais lattice CF: net spacer a. A piece of metal wire twisted at each end so as to form at one end a guard to keep the explosive in a shothole in place and at the other end another guard to hold the tamping in its place, thus providing an open space between explosive and tamping. When this is provided, the charge constitutes a cushion shot. Zern b. Piece of wood doweling which is interposed between charges to extend the column of explosive. Nelson c. A marker block. Also called spacer block. Long d. The tapered section of a pug joining the barrel to the die; in this section beyond the shaft carrying the screw or blades, the clay is compounded before it issues through the die. Dodd spacing The distance between adjacent shotholes in a direction parallel to the quarry or other face. Nelson Spackman System See: coal constituent classification spad

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a. A means of marking an underground survey station that consists of a flat spike in which is drilled a hole for the threading of a plumbline. BS, 7 b. See: spud spade drill See: flat drill spade-end wedge A type of deflecting wedge in boreholes. See also: deflecting wedge Long spadiard Corn. A worker in the tin mines. Also called spalliard. Standard, 2 spake A term used in South Wales for a train of personnel carriages, for use on the main slants at the beginning and end of each shift. The seats are so arranged that they are horizontal when the carriage is on the inclined slant. See also: man-riding car; man-riding conductor. Nelson spall a. A relatively thin, commonly curved and sharp-edged piece of rock produced by exfoliation. b. To break off in layers parallel to a surface. c. To break ore. Pieces of ore thus broken are called spalls. Also spelled: spawl. spalliard Eng. A pickman; a working miner. A laborer in tinworks. Also spelled spallier. spalling The chipping, fracturing, or fragmentation, and the upward and outward heaving, of rock caused by the action of a shock wave at a free surface or by release of pressure. Syn: exfoliation spalling floor A place for breaking ore with a 4- to 5-lb (1.8- to 2.3-kg) sledge hammer. span

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a. The horizontal distance between the side supports or solid abutments along sides of a roadway. See also: abutment; pressure arch. Nelson b. The horizontal distance between the supports of a bridge, arch, beam, or similar structural member. See also: clear span; effective span. Hammond spangle gold Aust. Smooth, flat scales of gold. spangolite A trigonal mineral, Cu6 Al(SO4 )(OH)12 Cl.3H2 O ; soft; vitreous; dark green; in Cochise County, AZ. Spanish chalk A variety of steatite in Aragon, Spain. Spanish emerald Emerald of the finest quality (presumably from South America). Schaller Spanish lazulite Iolite, a variety of cordierite. Spanish topaz a. Any orange, orange-brown, or orange-red variety of quartz resembling the color of topaz; e.g., heat-treated amethyst. CF: topaz; Madeira topaz. b. A wine-colored or brownish red citrine from Spain. spantone See: gypsum spar a. A term loosely applied to any transparent or translucent light-colored mineral that is readily cleavable having a vitreous luster; e.g., Iceland spar (calcite), fluorspar (flourite), feldspar, heavy spar (barite). b. Applied locally by miners to small clay veins found in coal seams. AGI c. Corn. Quartz. d. See: Iceland spar sparable ore 3016

A nonmetallic tin ore occurring in small granules. Osborne sparagmite A collective term for the late Percambrian fragmental rocks of Scandinavia, esp. the feldspathic sandstones of the Swedish Jotnian, consisting mainly of coarse arkoses and subarkoses, together with polygenetic conglomerates and graywackes. Etymol: Greek sparagma, fragment, thing torn, piece. AGI spare N. of Eng. A wedge from 6 to 8 in (15 to 20 cm) long for driving behind plates when adjusting them to the circle of the shaft. Also called spear wedge. spare face See: standby face sparite a. A descriptive term for the crystalline transparent or translucent interstitial component of limestone, consisting of clean, relatively coarse-grained calcite or aragonite that either accumulated during deposition or was introduced later as a cement. It is more coarsely crystalline than micrite, the grains having diameters that exceed 10 mu m. AGI b. A limestone in which the sparite cement is more abundant than the micrite matrix. AGI spark absorber See: absorber spark chamber An instrument for detecting and measuring nuclear radiation; analogous to the cloud chamber. It consists of numerous electrically charged metal plates mounted in a parallel array, the spaces between the plates being occupied by inert gas. Ionizing radiation causes sparks to jump between the plates along its path through the chamber. See also: bubble chamber; cloud chamber. Lyman sparker A marine seismic source that employs an electrical spark discharge to form the outgoing signal and produces a trace in the recorder showing the subbottom strata. Hy sparkle metal 3017

A matte containing about 74% copper. Webster 3rd spark test Identification of type of iron alloy by appearance of sparks emitted when rubbed on grindstone. Pryor, 3 sparry a. Pertaining to, resembling, or consisting of "spar"; e.g., sparry vein or sparry luster. Like spathic; as in feldspathic. See also: spar b. Pertaining to "sparite" esp. in allusion to the relative clarity, both in thin section and hand specimen, of the calcite cement; abounding with sparite, such as a sparry rock. sparry iron See: siderite sparry lode A lode filled with spar, e.g., fluorspar, calcspar, or heavy spar. sparse vitrain A field term to denote, in accordance with an arbitrary scale established for use in describing banded coal, a frequency of occurrence of vitrain bands comprising less than 15% of the total coal layer. CF: abundant vitrain; dominant vitrain; moderate vitrain. AGI spartaite A variety of calcite containing some manganese. Fay spartalite A former name for zincite. spate a. Corn. In mining, to fine for disobedience of orders. b. A variation of spall. spathic Resembling spar, esp. in regard to having good cleavage. Syn: spathose 3018

spathic iron A native ferrous carbonite, also called siderite, containing 48% iron and usually traces of manganese. It is the best native ore for making steel tools by the direct method formerly used. See also: siderite Sandstrom spathic iron ore See: siderite spathization Widely distributed crystallization of sparry carbonates, such as calcite and dolomite; development of relatively large sparry crystals that have good cleavage. AGI spathose See: spathic spathose iron Carbonate of iron, FeCO3 . See also: siderite spawl See: spall spawl beater See: sledger SP curve See: spontaneous potential curve spear a. One of several types of fishing tools designed to be driven and wedged inside of bits, rods, etc., lost in a borehole. CF: fishing tap Long b. A rodlike fishing tool having a barbed-hook end, used to recover rope, wire line, and other materials from a borehole. Long c. Eng. A wooden pump rod cut into lengths of about 40 ft (12 m) , and, for heavy work, often measuring 16 in (40.6 cm) square. Wrought iron spears are also used. Fay spearhead 3019

a. The point of convergence of two cross faces set off in the form of the letter V. TIME b. A conical head on a wire-line core barrel, engaged by the dogs on the overshot assembly for the purpose of removing the inner tube of the core barrel from a borehole. Long spear pyrite A marcasite in twin crystals resembling the head of a spear. See: marcasite special See: special rounds special flexible rope A wire rope composed of 6 strands of 37 wires each. Lewis special rounds Sometimes used to designate a very high quality or grade of drill diamonds. Long specialty steel A steel containing alloys that provide special properties, such as resistance to corrosion or to heavy load. Also called alloy steel. Hammond species A mineral distinguished from others by its unique chemical and physical properties; it may have varieties. AGI specific Word used with a special meaning in mineral dressing, where minerals of the same species often exhibit differences in their reactions. "Specific to" warns the observer that the process in hand is empirical in some ways, designed to apply to one specific orebody. Pryor, 3 specific adhesion The chemical bond between glued or cemented surfaces as distinct from any form of mechanical bond. Hammond specific adsorption 3020

Selective adsorbing action. Pryor, 3 specific damping capacity A measure of the vibrational energy absorbed by the rock and may be considered to be a measure of the internal friction. It is determined by the sharpness of resonance that is evident when a specimen is vibrated through a range of frequencies centered on the fundamental longitudinal resonant frequency. Damping of the dry type (coulomb damping) is commonly assumed to be independent of the velocity, and thus independent of the frequency, and is somewhat sensitive to moisture content. Syn: coulomb damping specific extraction of rock broken Quantity of broken rock (ore) in volume or weight per foot drilled or fired per quantity of explosive. Fraenkel specific gravity a. The ratio between the weight of a unit volume of a substance and that of some other standard substance, under standard conditions of temperature and pressure. For solids and liquids, the specific gravity is based upon water as the standard. The true specific gravity of a body is based on the volume of solid material, excluding all pores. The bulk or volume specific gravity is based upon the volume as a whole--i.e., the solid material with all included pores. The apparent specific gravity is based upon the volume of the solid material plus the volume of the sealed pores. See also: apparent specific gravity b. Ratio of densities of a gas and air, based on dry air = 1. Hartman, 2 c. The weight of a substance compared with the weight of an equal volume of pure water at 4 degrees C. Specific gravity is numerically equal to density given in grams per cubic centimeter or milliliter. CF: density specific-gravity hydrometer A hydrometer indicating the specific gravity or relation of the weight of a given liquid per unit volume to the weight of a given unit volume of water. See also: hydrometer; Marsh funnel. Long specific gravity of soil grains This is measured in a calibrated glass bottle with special precautions against the inclusion of air. Such testing is applied in many soil problem computations. See also: pycnometer specific heat

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a. Heat required to raise the temperature of a unit weight of air 1 degrees F (0.56 degrees C). Usually, the specific heat at constant pressure is used in air conditioning. For ordinary concrete and steel it is 0.22 Btu/lb/ degrees F and 0.12 Btu/lb/ degrees F (0.92 kJ/kg/ degrees C and 0.50 kJ/kg/ degrees C), respectively. Hartman, 2 b. The ratio of the amount of heat required to raise a unit weight of a material 1 degree to the amount of heat required to raise the same unit weight of water 1 degree. Brantly, 2 c. The heat in calories required to raise the temperature of 1 g of a substance 1 degrees C. Webster 3rd specific humidity a. The mass of moisture per unit mass of dry air. Roberts, 1 b. Absolute humidity, or weight of water vapor contained per unit weight of dry air. CF: relative humidity Hartman, 1 specific mineral See: essential mineral specific population Number of particles in unit volume of pulp. Pryor, 4 specific resistance See: resistivity specific retention The ratio of the volume of water that a given body of rock or soil will hold against the pull of gravity to the volume of the body itself. It is usually expressed as a percentage. CF: field capacity specific speed a. A factor by which the performance of any particular design of impeller for a centrifugal pump or water turbine can be computed. It is the speed in revolutions per minute at which a geometrically similar impeller of suitable diameter will rotate to deliver 1 gal/min (3.785 L/min) at 1 ft (30.5 cm) head in the case of a pump. In a water turbine, the specific speed is that at which a geometrically similar runner of suitable diameter will turn to develop 1 hp (746 W) under a head of 1 ft (30.5 cm). Hammond b. The particular speed at which a fan achieves its maximum efficiency. Roberts, 1 specific surface

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a. The surface area per unit of volume of soil particles. ASCE b. The ratio of the total surface of a substance (as an adsorbent) to its volume; surface area (as of a finely divided powder) per unit mass. Webster 3rd specific volume a. Volume of one gram at specified temperature. Pryor, 3 b. Volume per unit weight of dry air. Not equal to the reciprocal of density, which is based on unit volume of mixture. Measured in cubic feet per pound (cubic meters per kilogram). Hartman, 2 specific weight of sediment The dry weight per unit volume of the sediment in place. See also: dry density specific yield The ratio of the volume of water that a given mass of saturated rock or soil will yield by gravity to the volume of that mass. This ratio is stated as a percentage. CF: effective porosity specimen a. A sample, as of a fossil, rock, or ore. Among miners, it is often restricted to selected or handsome samples, such as fine pieces of ore, crystals, or fragments of quartz showing visible gold. CF: hand specimen b. A small mass of coal, rock, or, mineral, or soil, which gives, roughly, an idea of the kind and quality of the deposit from which it was derived. In the case of ore in particular, the specimen should admit of the identification of the various minerals present. A specimen cannot be viewed as a sample. Nelson specimen boss An employee whose duty is to watch carefully, in all parts of the mine, for the appearance of high-grade mineral, and when it is likely that such spots will be opened up, should be the first person at the face after the blast to prevent high-grading (the theft of valuable samples). Hoover specimen hunting Another name for high-grading. Hoover specimens In mineral dressing, unusually rich pieces of ore or characteristic constituents thereof in coarsely crystalline form--not representative samples. Pryor, 4 3023

speck A small piece of alluvial gold weighing up to 1 oz or 2 oz (28 g or 56 g). Gordon speckstone An early name for talc or steatite. Etymol: German "Speckstein", "bacon stone," alluding to its greasy feel. spectacle A two-handled frame for carrying well-boring tools. Standard, 2 spectacle stone An early popular name for selenite, alluding to its transparency. Fay spectral gamma-ray log Record of the radiation spectrum and relative intensities of gamma rays emitted by strata penetrated in drilling. Because of their different energies the relative amounts of radioactivity contributed by different elements can be determined. CF: gamma-ray well log See also: radioactivity log spectrometer An optical instrument similar to, but more versatile than, the simple spectroscope. Scales are provided for reading angles. A wavelength spectrometer is one designed or equipped in a manner to measure the wavelengths at which absorption bands occur in an absorption spectrum. spectrophotometer An instrument to detect very slight differences in color of solutions of different chemicals and thus measure the quantity of the chemical present. It consists of a light source, an optical prism for providing monochromatic light; i.e., light of a single wavelength only, and a device for measuring the intensity of the light beam after it has passed through the solution. Traces of aluminum in steel may be determined in this way. Also called spekker. Nelson spectrum a. A band of light showing in orderly succession the rainbow colors or isolated bands or colors corresponding to different wavelengths, as seen through a spectroscope or photographed in a spectrograph. The visible spectrum is only a small region in the vast 3024

spectrum of electromagnetic waves, which extend from the longest radio waves to the minutely short waves (gamma rays) emitted by radioactive elements. See also: emission spectrum; continuous spectrum; absorption spectrum. Anderson b. An array of visible light ordered according to its constituent wavelengths (colors) by being sent through a prism or diffraction grating. AGI c. An array of intensity values ordered according to any physical parameter, e.g. energy spectrum, mass spectrum, velocity spectrum. AGI d. Amplitude and phase response as a function of frequency for the components of a wavetrain, such as given by Fourier analysis, or as used to specify filter-response characteristics. Pl: "spectra." Adj: "spectral." spectrum colors The hues or wavelengths into which white light is separated upon passing through a transparent prism, six of which are readily distinguished by the normal human eye: red, orange, yellow, green, blue, and violet. See also: visible spectrum outside the visible range. specular Mirrorlike, as specular iron ore, which is a hard variety of hematite. See also: specularite specular hematite See: specularite specular iron Variety of hematite, Fe2 O3 , black, lustrous, metallic gleam. Mohs hardness, 5.5 to 6.5. May be micaceous in form. Contains 70% iron; sp gr, 4.9 to 5.3. See also: specularite; hematite. Pryor, 3 specular iron ore A variety of hematite with brilliant black color and metallic luster. See: hematite specularite A black or gray variety of hematite with splendant metallic luster, often showing iridescence; occurs in micaceous or foliated masses or in tabular or disklike crystals. Syn: specular hematite; gray hematite. See also: hematite; specular iron; iron glance. specular schist Metamorphosed oxide-facies iron formation characterized by a high percentage of strongly aligned flakes of specular hematite. CF: itabirite 3025

specular stone Mica. Standard, 2 speculative resources Undiscovered resources that may occur either in known types of deposits in favorable geologic settings where mineral discoveries have not been made, or in types of deposits as yet unrecognized for their economic potential. If exploration confirms their existence and reveals enough information about their quantity, grade, and quality, they will be reclassified as identified resources. USGS, 2 speed The length of belt, chain, cable, or other linkage which passes a fixed point within a given time. It is usually expressed in terms of feet per minute. In the case of the rolling chain conveyor, the load is moved at a rate double the chain speed. In screw conveyors, the speed is expressed in terms of revolutions per minute and the speed at which the material is conveyed is dependent upon speed, pitch of the screw, type of flight, angle of inclination, nature of material, etc. speedy moisture tester A calcium carbide method for the quick determination of moisture. A pressure gage is calibrated to give direct values of moisture content percent of soil samples. Nelson speiss Metallic arsenides and antimonides smelted from cobalt and lead ores. Pryor, 3 speisscobalt See: smaltite speleologist One who scientifically investigates caverns. speleology The scientific study or exploration of caverns and related features. speleothem A secondary mineral deposit formed in caves. 3026

spell A rest period for crews at furnace, stock house, etc., or a period of work in drilling the taphole; a change or turn. Fay spellerizing Subjecting the heated bloom to the action of rolls having regularly shaped projections on their working surface, then subjecting the bloom while still hot to the action of smoothfaced rolls. The surface working is said to give a dense texture to pipe made from the bloom, adapting it to resist corrosion. Liddell spelter Zinc of under 99.6% purity. Hammond Spence automatic desulfurizer An improved maletra furnace provided with automatic rakes. Fay Spence furnace A furnace of the muffle or reverberatory type, the ore being supported on shelves and stirred mechanically. Fay spencerite a. A monoclinic mineral, Zn4 (PO4 )2 (OH)2 .3H2 O ; pearly white. b. The synthetic material (Fe,Mn)3 (C,Si). spencite See: tritomite spend a. To break ground; to continue working. b. To exhaust by mining; to dig out; used in the phrase, to spend ground. Standard, 2 spent fuel Nuclear-reactor fuel that has been irradiated to the extent that it can no longer effectively sustain a chain reaction. Fuel becomes spent when its fissionable isotopes have been partially consumed and fission-product poisons have accumulated in it. Syn: depleted fuel 3027

spent shot A blasthole that has been fired, but has not done its work. spergenite A calcarenite that contains ooliths and fossil debris (such as bryozoan and foraminiferal fragments) and that has a quartz content not exceeding 10%. Type locality: Spergen Hill, situated a few miles southeast of Salem, Indiana, where the Salem Limestone (formerly the Spergen Limestone) is found. Syn: Bedford Limestone sperrylite An isometric mineral, PtAs2 ; pyrite group; tin white; sp gr, 10.6; occurs with heavymetal ores, also in placers. Sperry process A process for manufacturing white lead in which softened and desilverized lead anodes, preferably containing some bismuth, are placed in the Sperry cells. Direct current dissolves the lead from the anodes, and carbon dioxide is used to precipitate white lead (basic lead carbonate) from the solution. The Sperry process slime, which contains the impurities from the anodes, is washed, dried, and melted to an impure bismuth bullion, which goes to the bismuth refinery. USBM, 5 spessartine An isometric mineral, Mn3 Al2 (SiO4 )3 ; garnet group with Mn replaced by Fe and Mg; crystallizes as dodecahedra and trapezohedra; in skarns and granite pegmatites; may be of gem quality. Also spelled spessartite. CF: emildine Syn: manganese-aluminum garnet spessartite A "lamprophyre" composed of phenocrysts of green hornblende or clinopyroxene in a ground mass of sodic plagioclase, with accessory olivine, biotite, apatite, and opaque oxides. Named for Spessart, Germany. Syn: spessartine spew The cauliflowerlike blowout or outcrop of a lode that extends beyond the limits of the defined vein deeper down. sphaerocobaltite

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A trigonal mineral, CoCO3 ; calcite group; forms peach-blossom red spherical masses. Also spelled spherocobaltite. Syn: cobaltocalcite sphaerolitic See: spherulitic sphaerosiderite Alternate spelling of spherosiderite. sphagnum peat Peat composed mainly of bog moss. It is characterized by an open texture, is lightweight, has a high absorbing power, good isolating properties, a clean appearance, and freedom from black dust. Tomkeieff sphalerite a. An isometric mineral, ZnS , with Zn replaced by Fe with minor Mn, As, and Cd; trimorphous with wurtzite and matraite; perfect dodecahedral cleavage; resinous to adamantine; occurs with galena in veins and irregular replacement in limestone; a source of zinc. Syn: blende; zinc blende; jack; blackjack; steel jack; false galena; pseudogalena; mock ore; mock lead. See also: beta zinc sulfide b. The mineral group coloradoite, hawleyite, metacinnabar, sphalerite, stilleite, and tiemannite. sphene See: titanite sphenoid An open crystal form of two nonparallel faces which intersect two or three crystallographic axes. CF: dome; disphenoid. sphenolith A wedgelike igneous intrusion, partly concordant and partly discordant. AGI sphenomanganite See: manganite Sphenopterias 3029

A fernlike tree of the coal forest characterized by round-lobed pinnules that are contracted at the base. See also: Neuropteris sphere ore See: cockade ore spheric A general term applied to rocks made up of spherules. It includes such textures as oolitic, pisolitic, spherulitic, variolitic, orbicular, etc. Johannsen spherical dam A brick or concrete seal or stopping built into a roadway to close off an area against water. The convex surface is from the water side of the roadway. The construction is built well into the ground and all crevices cemented. Nelson spherical model A function frequently used when fitting mathematical models to experimental variograms, often in combination with a nugget model. spherical wave A seismic wave propagated from a point source whose front surfaces are concentric spheres. AGI spherical wave front Spherical surface that a given portion of a seismic impulse (in an isotropic medium) occupies at any particular time. AGI spherical weathering See: spheroidal weathering spherite a. The preferred spelling for sphaerite. English b. Spherical grains, including ovulite with concentric structure and spherulite with radial structure. Spencer, 2 spherocobaltite See: sphaerocobaltite 3030

spherocrystal A homogeneous spherulite formed of minute crystals branching outward from the center. See also: spherulite spheroid In general, any figure differing but little from a sphere. In geodesy, a mathematical figure closely approaching the geoid in form and size, and used as a surface of reference for geodetic surveys. spheroidal a. Having the shape of a spheroid. AGI b. Composed of spherulites. AGI c. Said of the texture of a rock composed of numerous spherulites. AGI spheroidal jointing See: spheroidal parting spheroidal parting A series of concentric and spheroidal or ellipsoidal cracks produced about compact nuclei in fine-grained, homogeneous rocks. CF: exfoliation; spheroidal weathering. Syn: spheroidal jointing spheroidal structure See: orbicular structure spheroidal weathering A form of chemical weathering in which concentric or spherical shells of decayed rock (ranging in diameter from 2 cm to 2 m) are successively loosened and separated from a block of rock by water penetrating the bounding joints or other fractures and attacking the block from all sides. It is similar to the larger-scale exfoliation produced usually by mechanical weathering. See also: spheroidal parting Syn: onion-skin weathering; concentric weathering; spherical weathering. CF: exfoliation spherosiderite A variety of siderite occurring in globular concretionary aggregates of bladelike crystals radiating from a center, generally in a clayey matrix (such as those in or below underclays associated with coal measures). It appears to be the result of weathering of 3031

water-logged sediments in which iron, leached out of surface soil, is redeposited in a lower zone characterized by reducing conditions. Also spelled sphaerosiderite. spherulite a. A rounded or spherical mass of acicular crystals, commonly of feldspar, radiating from a central point. Spherulites may range in size from microscopic to several centimeters in diameter. Also spelled: sphaerolite. AGI b. Any more or less spherical body or coarsely crystalline aggregate with a radial internal structure arranged around one or more centers, varying in size from microscopic grains to objects many centimeters in diameter, formed in a sedimentary rock in the place where it is now found; e.g., a minute particle of chalcedony in certain limestones, or a large carbonate concretion or nodule in shale. CF: spherite; variole. AGI c. A small (0.5 to 5 mm in diameter), spherical or spheroidal particle composed of a thin, dense calcareous outer layer with a sparry calcite core. It can originate by recrystallization or by biologic processes. AGI spherulitic Said of the texture of a rock composed of numerous spherulites; also, said of a rock containing spherulites. CF: variolitic; radiated. Syn: globular; sphaerolitic. AGI spider a. A ring inserted at the joints of the suspension column of a borehole pump. Radial vanes from the ring support a central sleeve, which acts as a steady bearing from the pump shaft. BS, 10 b. The bowl part of a spider and slips. Also called bowl. See also: spider and slips c. See: drum horn d. Assembly of radiating tie rods on the top of a furnace. ASTM spider and slips A gripping device used to grip and hold rods or casing while coupling or uncoupling them as they are being run into or pulled from a borehole. Also called bowl and slips. See also: spider spider gear A differential gear that rotates on its shaft in a rotating case. Nichols, 1 spiderweb rock A local term in Ohio for sandstone beds that show crossbedding on a small scale, which is complicated by intricate interlacing of fine-bedding planes. Frequently seen in sawed 3032

stones, esp. where the lamination is slightly oblique or irregular. It is very like the grain of wood that shows in a planed board. spiegeleisen An alloy containing 10% to 25% manganese. Is used in steelmaking as a deoxidizing agent and to raise the manganese content of the steel. Also called spiegel and psiegel iron. CTD; Henderson; Camp spigot product In ore dressing, the material discharged at the bottom of the hydraulic classifier. Newton, 1 spike amygdule A cylindrical amygdule whose longer axis is at right angles to the bedding. spike driver In bituminous coal mining, one who drives a team of two or more draft animals in tandem for hauling wagons or cars of coal. Also called spike-team driver. DOT spike team a. A team consisting of three draft animals, two of which are at the pole while the third pads. Fay b. Three mules, two abreast and one in the lead, used in a mine to haul coal cars. Fay spike-team driver See: spike driver spiking A term used in the United States for the operation of adding ferromanganese, silicomanganese, or other deoxidizing agent, to an open hearth bath for the immediate stoppage of all oxidizing reactions. Osborne spile a. A large timber driven into the ground, used as a foundation; a pile. Crispin b. A plank driven ahead of a tunnel face for roof support. Also called forepole. Nichols, 1 c. A temporary lagging driven ahead on levels in loose ground. See also: spill d. A short piece 3033

of plank sharpened flatways and used for driving into watery strata as sheet piling to assist in checking the flow. spiler An ironstone miner who excavates and sets timber supports in roadways through wastes and disturbed ground. Nelson Spilhaus-Miller sea sampler An instrument resembling the bathythermograph and operating in a similar fashion, with the additional ability of obtaining water samples at discrete depths within the limit of operation. Basically, a bathythermograph to which 12 small seawater sampling bottles are attached, it performs the same functions as a cast of Nansen bottles and reversing thermometers to limited depths, but with less accuracy. It is useful for studies of shallow water areas, bays, and estuaries, where rapidity of sampling is of greater importance than the degree of accuracy of temperatures. Hunt spiling a. Forepoling over timber and steel supports in weak, loose beds. See also: spilling b. Driving timbers ahead of an advancing tunnel through treacherous, loose, watery ground. Pryor, 3 spilite An altered basalt, characteristically amygdaloidal or vesicular, in which the feldspar has been albitized and is typically accompanied by chlorite, calcite, epidote, chalcedony, prehnite, or other low-temperature hydrous crystallization products characteristic of a greenstone. Spilite often occurs as submarine lava flows and exhibits pillow structure. Adj: spilitic. The name was given by Brongniart in 1827. AGI spilitic suite A group of altered extrusive and minor intrusive basaltic rocks that characteristically have a high albite content. The group is named for its type member, spilite. AGI spilitization Albitization of a basalt to form a spilite. AGI spill

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Any of the thick laths or poles driven ahead of the main timbering to support the roof or sides in advancing a level in loose ground, or to support the sides of a shaft when sinking through a stratum of loose ground. Syn: spile spilla Ore, pulp, circulating liquor inadvertently discharged from flow line and requiring appropriate means of recovery or removal. Syn: spillage Pryor, 4 spillage See: spilla spillage conveyor A small, short conveyor to lift coal out of a spillage pit and deliver it into a mine car or onto the main conveyor. It is usually a chain conveyor run either continuously or intermittently. Nelson spillage pit An opening below the loading point of a trunk or gate conveyor, to receive spillage. If the output is small, the pit may be emptied by hand once or twice in a shift, but if big tonnages are loaded, a spillage conveyor is installed. Nelson spilling A method of tunneling through loose, running ground by driving spills (sharp-edged thick boards or steel rods) ahead and around timber or steel frames. Nelson spill pit See: runoff pit spill trough A trough to retrieve melted brass that may be spilled in pouring from a crucible into a flask. Standard, 2 spilosite A rock representing an early stage in the formation of adinol or spotted slate. CF: adinole spindle 3035

a. Shaft of a machine tool on which a cutter or grinding wheel may be mounted. ASM, 1 b. Metal shaft to which a mounted wheel is cemented. ASM, 1 c. In founding, a rod or pipe used in forming a core. Standard, 2 spindle conveyor A chain-on-end conveyor in which the chain pins are extended in a vertical plane, usually of enlarged diameter in that portion above the chain, on which special revolvable fixtures can be rotated, for the purpose of spraying or drying. Outboard rollers or sliding shoes support the chain and product. spindle speed a. Same as bit rotational speed. Long b. The number of times the drive rod of a gearfeed-drill swivel head must turn to advance the attached drill string 1 in (2.54 cm). Long spindle stage A graduated horizontal rotation axis attached to a microscope stage for observation and measurement of optical properties of small crystals. CF: goniometer; universal stage. spinel a. An isometric mineral, MgAl2 O4 ; crystallizes as octahedra; colorless to pale tints; Mohs hardness, 7.5 to 8; in high-temperature metamorphic rocks, contact metamorphosed limestones, serpentinites, and ultramafic rocks; may be of gem quality. b. The spinel series gahnite, galaxite, hercynite, and spinel. c. The mineral group brunogeierite, chromite, cochromite, coulsonite, cuprospinel, franklinite, gahnite, galaxite, hercynite, jacobsite, magnesiochromite, magnesioferrite, magnetite, manganochromite, nichromite, ringwoodite, spinel, trevorite, ulvoespinel, and vuorelainenite. d. Minerals with the spinel structure, such as the linnaeite group. e. A synthetic crystal with spinel structure that is used as a gemstone, a refractory, or for instrument bearings; e.g., ferrospinel. Also spelled spinelle; spinell; spinelite. See also: magnesium aluminate spinel emery A mixture of spinel, corundum, and magnetite, the corundum being present in variable proportions. It is a heavy, black, fine-grained aggregate. Dark gray crystals of corundum appear in the best varieties. spinellid See: spinel 3036

spinellite A medium- to coarse-grained hypidiomorphic-granular titaniferous magnetite-rich igneous rock with spinel from a few percent to 20%. spinifex texture Interpenetrating lacy elongate olivine crystals in komatiite, commonly considered to have been formed by quenching. Their disposition resembles the intermesh of an Australian grass for which the texture is named. AGI spinning cable A flexible wire or plant-fiber cable or rope used as a spinning chain. See also: spinning chain spinning chain Link chain wrapped several times around drill rod, casing, or pipe and used on the drum to spin up or spin out such equipment when it is being pulled or run into a borehole. A rope or flexible wire cable may be used in lieu of a chain. Long spinning fiber Asbestos suitable for the spinning of asbestos fabrics. spinning rope A plant-fiber rope used for the same purpose as a spinning chain. See also: spinning chain spin out To unscrew lengths of drill rod casing, or pipe by mechanical means, using a spinning chain, rope, or cable in conjunction with power derived from the cathead or other rotating device. Long S-P interval In earthquake seismology, the time interval between the first arrivals of transverse (S) and longitudinal (P) waves, which is proportional to the distance from the earthquake source. AGI spinthariscope 3037

Screen coated with zinc sulfide or other fluorescing substance, on which scintillations are observable when bombarded by radioactive rays. Pryor, 3 spin up To screw lengths of drill rod, casing, or pipe together by mechanical means by using a spinning chain, cable, or rope in conjunction with power derived from the cathead or other rotating device. Long spiral a. A spiral coal chute that mechanically separates the slate from the coal. The lighter, irregularly-shaped coal falls over the edge of the spiral while the flatter and heavier slate adheres somewhat to the chute surface and is carried down to a special pocket. b. The Humphrey's spiral is successfully used in recovering chromite from chrome; sands, rutile, ilmenite, and zircon from beach sands (Florida): and tantalum minerals and lepidolite from crushed ores. Also used in concentrating some iron ores and coal. See also: Humphrey's spiral spiralarm methanometer An instrument that depends on the heat output of burning methane for its action. There are two varieties: those having a controlled flame burning within them and those in which combustion of the methane occurs on electrically heated filaments. A combustible gas alarm making use of the flame principle is the Naylor Spiralarm. Roberts, 1 spiral classifier See: Akins' classifier spiral cleaner A device for removing dirt from a conveyor belt. Nichols, 1 spiral coal cleaner A spiral chute in which the plate is inclined towards the center of the spiral. The stone tends to flow down centrally, the coal tends to slide off around the outside of the spiral. They are seldom used as coal cleaners. Nelson spiral concentrator A sluice formed in five or six tight spirals, in which centrifugal force aids the separating effect of sluice action. See also: Humphrey's spiral 3038

spiral conveyor See: screw conveyor spiral core A piece of core the outside surface of which is rifled. See also: rifle Long spiral curve a. A curve of gradually increasing radius that allows an easy transition between a circular arc and a straight on a road or railway. Hammond b. In railroad or highway surveying, a curve of progessively decreasing (or increasing) radius used in joining a tangent with a simple circular curve or in joining two circular curves of different radii. Syn: transition curve spiral grooving See: rifling spiral gummer A screw device, attached to a longwall coal cutter, for removing the holings and depositing them either in the track of the machine or at the side clear of the face. It is designed in two types: end discharge and side discharge. Nelson spiral hole A borehole that follows a corkscrewlike course. CF: rifle spiraling a. Rifling. Nichols, 2 b. A drill hole twisting into a spiral around its intended centerline. Nichols, 2 spiral level A section of convex glass tube containing fluid and an air bubble. When level, the air bubble centers itself on an etched line on the tube. spiral system In open pit mining, a haul road arranged spirally along the perimeter walls of the pit so that gradient of road is more or less uniform from the bottom to the top of the pit. 3039

spiral track A track layout for rail or road transport from large opencast pits. The track is arranged spirally along the steep rise from the coal or ore benches so that the gradient is moderate throughout. Nelson Spiral Vane Disk Cutter Trade name for a cutter loader incorporating a special variety of shearer head. The Mark II model consists of section plates welded together to form a composite whole spiral. The disk is made in different sizes to give cutting diameters of from 31 to 72 in (79 to 183 cm) with a maximum web depth of 30 in (76 cm). A single spiral is used for softer coals and a double spiral for hard coals. A plow attached to the machine throws the coal onto the conveyor. Nelson spiral worm A device to withdraw broken rods from a borehole. It is lowered down the hole and the screw is turned around until it grips the broken rod below the joint. See also: wad hook; wad coil. Nelson spire A kind of fuse. The tube carrying a train to the charge in a blasthole. Also called reed or rush, because these, as well as spires of grass, are used for the purpose. See also: reed Spirelmo smoke helmet A helmet in which the crown and frontpiece are blocked out of rawhide, and the front shield is fitted with two mica windows in hinged aluminum frames. It has a twin-tubed air feed on each side of the helmet and a valve for the escape of excess and vitiated air. Air is supplied through an armored hose from double-acting bellows or a blower worked by a second person at the fresh air base. Airtightness is obtained by means of a soft leather apron secured in position about the neck and shoulders. Illumination is provided by portable electric lamps, and communication with the wearer by an approved type of mine telephone. Sinclair, 1; Mason spirit of copper Acetic acid obtained by distilling copper acetate. spirits of niter a. Nitric acid. Osborne b. A solution of ethyl nitrite in alcohol. Osborne 3040

spirits of sulfur Sulfurous acid. Osborne spirits of verdigris Acetic acid. Osborne spirits of vinegar Dilute acetic acid. Osborne spirits of wine Ethyl alcohol. Osborne spirits of wood Methyl alcohol. Osborne spiroffite A monoclinic mineral, (Mn,Zn)2 Te3 O8 ; red to purple. spitted fuse Slow-burning fuse that has been cut open at the lighting end for ease of ignition. A small quantity of the plastic explosive used in the hole is sometimes inserted in the cut. Pryor, 3 spitting a. Lighting the fuse for a blast. b. An action of or appearance on the surface of slowly cooled, large masses of melted silver or platinum, in which the crust is forcibly perforated by jets of oxygen, often carrying with them drops of molten metal. Also called sprouting. Standard, 2 spitting rock A rock mass under stress that ejects small fragments with considerable velocity on breaking. spitzkasten

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A series of hopper-shaped or pointed boxes for separating mineral-bearing slimes according to fineness, in which the width of each box is double that of its predecessor, while the lengths increase by arithmetical progression. As used in flotation, it is the froth-separating compartment of mechanical-agitation-type flotation machines. Also called spitz. See also: funnel box spitzlutten Hydraulic classifiers shaped like the spitzkasten, but having provision for pressure water to flow upward from near the apex, thus improving efficiency of separation. Pryor, 3 splasher a. A plate lined with firebrick and placed over the iron trough next to the taphole to keep down flame that blows from the taphole during a cast. Fay b. A water spray system for the protection of the metal structure immediately above the tapping hole during the tapping of a blast furnace. Henderson splash man A laborer who shovels charcoal over the surface of molten copper being poured from a reverberatory furnace into a tilting ladle to prevent excess oxidation of metal. DOT splay One of a series of divergent small faults at the extremities of a major fault. Splays are typically associated with rifts. splay faulting Minor faulting that diverges from a longer dislocation at an acute angle. splendent Applied to the degree of luster of a mineral, reflecting with brilliancy and giving welldefined images, such as hematite or cassiterite. splice a. A joint made in a broken haulage rope. Splicing is a skilled job and the rope ends are unlaid for a length on each side of the break and reformed to a definite pattern. Nelson b. Generally used to designate an insulated reconnection of wires of an electric cable after it has been cut. BCI c. To unite two ropes by interweaving the strands. splice box 3042

An enclosed connector permitting short sections of cable to be connected together to obtain a portable cable of the required length. spliced Said of a vein that pinches out and is overlapped by another parallel vein. splint coal A miner's term long used in Eastern United States and Scotland for certain hard dull coals with a distinctive type of fracture. Splint coals are irregular and blocky, with an uneven rough fracture, grayish black in color and of granular texture. Splint coals are banded coals. Coals containing more than 5% of anthraxylon and more than 30% of opaque attritus determined by microscopic examination are classed as splint coal. The content of anthraxylon and opaque matter is determined perpendicular to the bedding across the entire thin section (2 to 3 cm in width). The opaque attrital portion of the splint coal may be intercalated with fine, hairlike streaks of anthraxylon. It occurs mainly as bands and benches in otherwise bright-banded coal and is wide-spread in bituminous coal seams. Corresponds either to duroclarite or, more frequently, to clarodurite according to the ratio of vitrinite and inertinite. May also correspond to vitrinertite. IHCP splintery fracture The property shown by certain minerals or rocks of breaking or fracturing into elongated fragments like splinters of wood. split a. To divide the air current into separate circuits to ventilate more than one section of the mine. CF: air split b. The workings ventilated by that branch. c. A bench separated by a considerable interval from the other benches of a coal bed. d. The upper or lower portion of a divided coal seam. CTD e. To divide a pillar or post by driving one or more roads through it. f. A layer of coal which has separated from its parent seam. See also: split seam; ventilation; splitting. Nelson g. The process of dividing a core lengthwise, dividing a granular material into several representative parts for sending samples to several interested parties or reducing either core storage space or the quantity of material retained as a sample. Long h. The division of a bed of coal into two or more horizontal sections by intervening rock strata. Hudson split-barrel sampler A drive-type soil sampler with a split barrel; also a swivel-type double-tube core barrel, the inner tube of which is split. Syn: split-tube sampler 3043

split brilliant A brilliant split apart at the base of its pyramidal forms, so as to make two gems. Standard, 2 split bushing A bushing made in two pieces, for ease of insertion and removal. Nichols, 1 split check A system of leasing practiced at Cripple Creek, Colorado, whereby the miners and company divide the profits. von Bernewitz split coal Coalbed separated by clay, shale, or sandstone parting that thickens so that both benches cannot be mined together. AGI split core A core that has been split lengthwise into halves or quarters. Long split core barrel A type of core barrel which can be opened longitudinally to remove the core. BS, 9 split inner-tube core barrel A double-tube core barrel with the inner tube split lengthwise. Long split lagging Drum lagging made in two pieces to allow changing it without dismantling the drum. Nichols, 1 split-ring core lifter A hardened steel having an open slit, an outside taper, an inside or outside serrated surface. In its expanded state, it allows the core to pass through it freely, but when the drill string is lifted, the outside taper surface slides downward into the bevel of the bit or reaming shell, causing the ring to contract and grip tightly the core which it surrounds. Also called core catcher; core gripper; core lifter; ring lifter; split-ring lifter; spring lifter. Long 3044

split-ring lifter See: split-ring core lifter split rock A rock possessing tabular structure, or which cleaves easily in the lines of lamination, and is consequently suitable for flagging and curbstones. splits In mine ventilation, airways connected in parallel. Hartman, 2 split seam A coal seam that has separated into two or more layers which may, or may not, rejoin some distance away. Syn: coal split See also: multiple splitting split shovel A device for sampling fine ore, consisting of a fork in which the prongs are separate scoops, each scoop being the same width as the open spaces between. split spread A type of seismic spread in which the shot point is at the center of the arrangement of geophones. It is commonly used for continuous profiling and for dip shooting. Syn: straddle spread; symmetric spread. AGI split sprocket A two-piece sprocket that can be assembled on a shaft without removing the shaft bearings. Nichols, 1 split system a. A system of ventilation in which air is split along the airways or at the face. See also: natural splitting; controlled splitting. b. Historically, a combination of warm air heating and radiator heating. Also used for other combinations, such as hot water steam, steam warm air, etc. Strock, 2 split the air See: split 3045

splitting a. Parting of a coalbed into two or more benches separated by other rocks. AGI b. In mine ventilation, the practice of connecting airways in parallel by dividing the total air flow among them. Hartman, 2 c. Abrasion of a rock fragment resulting in the production of two or three subequal parts or grains. AGI d. The property or tendency of a stratified rock of separating along a plane or surface of parting. AGI e. The sampling of a large mass of loose material (e.g., a sediment) by dividing it into two or more parts; e.g., quartering. AGI splitting knife A knife used for splitting leather or for diamond cleaving. Standard, 2 splitting method A method of mining pillars seldom followed. A room is first driven through the pillars, splitting them into smaller blocks. The pockets are turned at right angles and are driven into the blocks. This method is really gouging the pillars and is wasteful. Lewis splitting of air See: ventilation; splitting. splitting shot Arkansas. A shot put into a large mass of coal detached by a previous blast. See also: block hole split-tube barrel See: soil sampler; split-barrel sampler. split-tube sampler See: soil sampler; split-barrel sampler. CF: solid-barrel sampler spodumene A monoclinic mineral, LiAlSi2 O6 ; pyroxene group; prismatic cleavage; in granite pegmatites in crystals up to scores of meters long (called logs); a source of lithium; may be of gem quality (lavender kunzite, green hiddenite). Formerly called triphane. Syn: lithia amethyst; lithia emerald. spoil 3046

Overburden, nonore, or other waste material removed in mining, quarrying, dredging, or excavating. See also: waste spoil bank a. A term common in surface mining to designate the accumulation of overburden. BCI b. Underground refuse piled outside. BCI c. That part of a mine from which coal has been removed and the space more or less filled up with waste. BCI d. To leave coal and other minerals that are not marketable in a mine. See also: spoil heap spoil dam An earthen dike forming a depression in which returns from a borehole can be collected and retained. Long spoil heap a. The pile of dirt produced by mining operations and stacked at the surface of a mine either in conical heaps or in layered deposits. Syn: dump; tip. Nelson b. A pile of refuse material from an excavation or mining operation; e.g., a pile of dirt removed from, and stacked at the surface of, a mine in a conical heap or in layered deposits, such as a tip heap from a coal mine. See also: spoil bank spoil-heap fire The spontaneous heating and burning of small coal, carbonaceous shale, and perhaps iron pyrites in spoil heaps. Nelson spoil pile See: waste dump spoil pool The reservoir formed by a spoil dam in which the returns from a borehole collect and are retained. CF: sludge pit; sump. Long spoils a. See: cuttings b. The debris or waste material from a mine. Long sponge a. A form of metal characterized by a porous condition, which is the result of the decomposition or reduction of a compound without fusion. The term is applied to forms 3047

of iron, the platinum-group metals, titanium, and zirconium. Metal has appearance of a sponge due to high porosity. ASM, 1 b. Hafnium produced by the Kroll process. Thomas sponge iron powder Ground and sized sponge iron, which may have been purified or annealed or both. ASTM sponge metal A form of metal characterized by a porous condition, which is the result of the decomposition or reduction of a compound without fusion. Metal has the appearance of a sponge due to high porosity. ASM, 1 spongy Said of a vesicular rock structure with thin partitions between the vesicles, thus resembling a sponge. spongy iron See: reduced iron spontaneous Used to describe the driving potential that causes electric currents to circulate in boreholes. These currents are not in any way deliberately induced by the well-logging equipment. Also called self-potential; SP curve. See also: spontaneous potential curve spontaneous combustion a. The heating and slow combustion of coal and coaly material initiated by the absorption of oxygen. The two main factors involved are (1) a coal of a suitable chemical and physical nature; and (2) sufficient broken coal and air leaking through it to supply the oxygen needed. The heat generated is retained with consequent rise in temperature. See also: gob fire; hydrogen sulfide; open fire; weathering of coal. Nelson b. The outbreak of fire in combustible material that occurs without the direct application of a flame or a spark. It is usually caused by slow oxidation processes (such as atmospheric oxidation or bacterial fermentation) under conditions that do not permit the dissipation of heat. c. Ignition that can occur when certain materials such as tung oil are stored in bulk, resulting from the generation of heat, which cannot be readily dissipated; often heat is generated by microbial action. Also known as spontaneous ignition. McGraw-Hill, 1 spontaneous polarization 3048

a. Electrochemical reactions of certain orebodies causing spontaneous electrical potentials. Schieferdecker b. See: self-potential method; spontaneous potential method. spontaneous potential curve The electric log curve that records changes in natural potential along an uncased borehole. Small voltages are developed between mud filtrate and formation water of an invaded bed, and also across the shale-to-mud interface. These electrochemical components are augmented by an electrokinetic potential (streaming potential) developed when mud filtrate moves toward a formation region of lower fluid pressure through the mud cake. Where formation waters are less resistive (more saline) than drilling-mud filtrate, the spontaneous-potential curve deflects to the left from the shale baseline. First used about 1932, the curve was added to the resistivity log to make up the basic electric log of well-logging practive. Syn: SP curve; self-potential curve. AGI spontaneous-potential method See: self-potential method spontaneous potential method An electrical method in which a potential field caused by spontaneous electrochemical phenomena is measured. Syn: self-potential method; spontaneous polarization. AGI spool a. Cast iron distance piece placed between timbers. Hammond b. To wind rope or cable on a hoist drum. Long c. The drum of a hoist. Long d. The movable part of a slide-type hydraulic valve. Nichols, 1 e. To wind in a winch cable. Nichols, 1 spool-type roller conveyor A type of roller conveyor in which the rolls are of conical or tapered shape with a diameter at the ends of roll larger than at the center. spoon A tool for cleaning dust or sludge from quarry blasting holes. Syn: scraper spooner In bituminous coal mining, a laborer who scoops drillings out of boreholes in which explosives are to be charged for blasting down coal, using a slender iron rod with a cupshaped projection bent at right angles to the handle. DOT 3049

spooning Many mineral raw materials, such as petroleum, cementation water (water containing dissolved copper or iron sulfates or other metal compounds), or brine are extracted by pumping through boreholes. In spooning, a long spoon (a hollow cylinder with a bottom equipped with a clap valve, or ball valve, and open above) is attached to a cable that is let down into the boreholes where the cylinder fills with the liquid; this is emptied out after the cylinder is raised. Stoces spoon proof Test-ladle specimen taken during various stages of melting and fining. ASTM spoon sampler A rotating soil sampler, fitted with an auger-type cutting shoe. Long spore Part of the reproduction organs of many coal measures' plants. There are two kinds, namely, megaspores (female) and microspores (male). They are found in most coal seams, particularly the dull layers. Megaspores vary from 1 to 5 mm in size, and microspores (or pollen grains) from about 0.01 to 0.1 mm. Nelson spore coal a. Coal in which the attritus contains a large amount of spore matter along with transparent attritus. See also: cannel coal b. Coal formed out of the spores of lycopods. sporinite A maceral of the exinite group consisting of spore exines generally much flattened parallel to stratification. CF: cutinite See also: resinite sporinite coal This type of coal consists of more than 50% of spores (microspores and megaspores). Other structured components uniformly distributed through the coal are cuticles, resin bodies, and gelified and fusinized tissues. Hand specimens of low rank sporinite coal are brownish, with matt or granular surfaces. The coal may have high or low ash and occurs in seams of different geological, age but is particularly common as bands of limited thickness in seams of the Lower Carboniferous. Sporinite coal naturally admixed with medium rank gelitocollinite coals is used for coking. IHCP sporogelite 3050

A colloidal form of aluminum hydroxide, Al2 O3 .H2 O , occurring as one of the constituents of bauxite. Also called cliachite; alumogel. Syn: diasporogelite spot a. To mark the site at which a borehole is to be drilled, a piece of equipment placed, or a structure built. Long b. To set a drill or piece of machinery at a preselected site. Long c. An inclusion in a diamond. Long d. To direct to the exact loading or dumping place. Nichols, 1 spot-bolting The use of one or just a few roof bolts at spot locations. USBM, 4 spot cooler Low capacity, semiportable refrigeration unit of 150,000 to 500,000 Btu/h (44 to 146.5 kW) cooling capacity that is used in cooling sites of limited extent, such as an underground enginehouse or the face of a development end. The refrigerant used is nontoxic, and an electric or compressed-air drive is applied to a reciprocating compressor. Roberts, 1 spot level The reduced level of any survey point. Hammond spot log A log or marker placed to show a truck driver the spot to stop to be loaded. Nichols, 1 spotted schist See: spotted slate spotted slate A slaty or schistose argillaceous rock whose spotted appearance is the result of incipient growth of porphyroblasts in response to contact metamorphism of low to medium intensity. CF: desmosite; spilosite; adinole. See also: fleckschiefer; fruchtschiefer; garbenschiefer; maculose. Syn: spotted schist; knotted schist; knotted slate. AGI spotter

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a. In truck usage, the person who directs the driver into loading or dumping position. Nichols, 1 b. In a pile driver, the horizontal connection between the machinery deck and the lead (pile guide). Nichols, 1 c. See: car pincher spot tests Simple and speedy qualitative tests used to identify minerals species when prospecting, valuing a deposit, or testing mill products. Pryor, 3 spotting hoist A small haulage engine used for bringing mine cars into the correct position under a loading chute, feeder or other point. See also: pickrose hoist spotty ore Ore in which the valuable material is concentrated irregularly as small particles; e.g., coarse gold in low-grade rocks. Nelson spout delivery pump A pump, similar to a diaphragm pump, that is not capable of delivering water above its own height. See also: force pump spoutman Person who directs the pouring of slag from a ladle through a spout into a reverberatory furnace used for smelting. DOT sprag a. A short wooden prop set in a slanting position for supporting the coal during the operation of holding. b. To chock or stop, as a vehicle or wheel, by a sprag; prop. See also: spur c. The horizontal member of a square act of timbers running parallel to the axis of a heading. Stauffer d. See: rod spear; stell. spragger In anthracite and bituminous coal mining, a laborer who rides trains of cars and controls their free movement down gently sloping inclines by throwing switches and by poking sprags (short, stout, metal or wooden rods) between the wheel spokes to stop them. DOT spragging The act of checking a mine car with a sprag. Korson 3052

sprag road A mine road having such a sharp grade that sprags are needed to control the descent of a car; hence, two-, three-, or four-sprag road. See also: sprag spray In a hydrocyclone, the discharge from the apex in spray form, showing that the cyclone is not overloaded. Pryor, 3 spraying machine A machine that applies a spray under pressure on mine timber supports to preserve and fireproof them. It may also be used for limewashing and water spraying of dust. The machine is mounted on wheels and operated by compressed air. Nelson spraying screen A screen used for the removal, by spraying, of fine solids present among or adhering to larger particles. BS, 5 sprays Appliances to damp deposits of dust in tunnels and workings before and after shotfiring and loading operations. Water sprays are also used along dusty roadways. Various types of mist projectors and atomizers are used and effect considerable improvement, but the dust trapped consists chiefly of the coarser particles. In many dusty mines, a water pipe system extends throughout the workings and sprays are employed at all loading and other dusty points. Sprays are also used to suppress dust at coal and ore processing plants. See also: whale-type jib spray water See: rinsing water spread a. The area covered at a given thickness by a given quantity of such materials as chippings or road binder. Hammond b. The surface in proportion to the depth of a stone. Hess c. The surface or width at the girdle in proportion to the depth of a cut stone, such as a diamond. d. The layout of geophone groups from which data from a single shot are recorded simultaneously. Syn: seismometer spread; seismic spread. spreader 3053

a. A horizontal timber below the cap of a set, to stiffen the legs and to support the brattice when there are two air courses in the same gangway. b. A piece of timber stretched across a shaft as a temporary support of the walls. c. A tool used in sharpening machine drill bits. Fay d. A strut in a tunnel or heading timber sets. Nelson e. A machine which spreads dumped material with its blades. Nelson spreader chains Chains joining the end of the tail chain to ends of the spreader. Zern spreader operator See: tripper man spread recorder An instrument used in bridge testing to measure any outward spread of an abutment under load. See also: rotation recorder spring a. To enlarge the bottom of a drill hole by small charges of a high explosive in order to make room for the full charge; to chamber a drill hole. See also: camouflet b. To chamber. See also: chamber c. A general name for any natural discharge of hot or cold pure or mineralized water. spring auxillary cylinder A heavy tension spring, enclosed in a cylinder, which is connected to the panline of certain types of shaker conveyors to keep the conveyor in tension. It is attached to the conveyor by a driving chain and to a prop by a fixing chain. Keeping the conveyor in tension, it is claimed, will save the conveyor connections and increase the output. Jones, 1 spring constant Force that produces a unit elongation of the spring used in geophysical instruments. AGI spring core lifter See: core lifter spring dart

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a. A tool used to retrieve lost boring gear. Pryor, 3 b. A device to withdraw the steel casing from a borehole when finished. The casing is cut into convenient lengths and then the spring dart is lowered to bring up each length separately. The dart springs open immediately when it meets a cut or recess in the casing, which length it then grips and lifts to the surface. Nelson springing a. A quarry blasting method in which a succession of charges is fired in a borehole to open up a chamber. BS, 12 b. Enlarging the bottom of a drill hole by exploding a small charge in it. Nichols, 1 c. In certain types of rock, large quantities of stone can be blasted down by the method known as springing the shothole. The technique requires that the rock contains well-defined bedding or jointing planes, such as are found in most sedimentary and some igneous rocks, particularly granite. The principle of springing is to drill a borehole with a heavy burden and then explode a succession of gradually increasing charges of black powder so that the bedding planes or joints are opened up to permit the placing of a large final charge. Syn: bullying; overspringing. McAdam, 2 springing a hole See: springing spring lifter See: core lifter spring line The meeting of the roof arch and the sides of a tunnel. Nichols, 1 spring-loaded Held in contact or engagement by springs. Nichols, 1 spring-roll crusher A crushing machine similar to the double-roll crusher with the difference that springs are fixed to the bearings of one roll. Nelson spring rolls Crushing rolls used in ore breaking. Two parallel cylinders, mounted horizontally, are held apart by shims, and pressed together by powerful springs. Crushable rocks falling between them are drawn down as the cylinders revolve, but unbreakable material causes the springs to yield and let it pass without damage. Pryor, 3 3055

spring washer A washer consisting of a steel ring cut through and bent into helical form, which prevents a nut from unscrewing. Hammond sprinkling An act of spraying water into the atmosphere and on coal surfaces to allay coal dust. BCI sprocket A gear that meshes with a chain or crawler track. Nichols, 1 sprocket gear A gear that meshes with a roller or silent chain. Nichols, 1 sprue hole A pouring hole in a mold; a gate. Standard, 2 spud a. To break ground with a drilling rig at the start of well-drilling operations. Syn: spud-in b. To bore, as the first 50 ft (15 m) of an oil well, by the use of a bull wheel. Standard, 2 c. To commence drilling operations by making a hole. Wheeler, R.R. d. To begin the drilling of a borehole with a spud or diamond-point bit. Long e. An offset type of fishing tool used to clear a space around tools stuck in a borehole. Long f. A cabletool drill bit. Long g. An anchorage during dredging provided by a steel post underneath a dredger that can be lowered by a toothed rack or by ropes until it is secured in the seabed, riverbed, or dredge pond. Hammond spud bit a. A mud or diamond-point bit used to drill through overburden or soil down to bedrock. Long b. A broad, dull, chisel-face drilling tool for working in earth down to rock with a churn or cabletool drill. Long spudded-in A term applied to a borehole that has been started and the hole has reached bedrock and/or the standpipe has been set. Long spudder 3056

a. A churn drill, churn-drill operator, or the special bit used to begin a borehole by rotary, diamond, or churn drills. Long b. A colloquialism for a small drilling-rig. Williams spudder drill See: churn drill spudding a. The operation, in rope drilling, of boring through the subsoil at the start of a hole. BS, 9 b. In diamond and/or rotary drilling, a general term applied to drilling through overburden with a fishtail bit, drag bit, or diamond-point bit. Long c. Sinking a conductor, standpipe, or casing with a churn- or cable-type drill rig. Long spudding bit a. A broad dull drilling tool for working in earth down to the rock. Standard, 2 b. A heavy chisel bit used in percussive drilling to drill through subsoil. BS, 9 c. See: spud bit d. The bit used to start the hole. When the hole is deep enough, regular drilling tools are substituted. Williams spudding boreholes The working of a cable drill up and down on a short length of rope, when passing through the superficial deposits down to bedrock. This section of hole is cased. Nelson spudding drill A drill that makes a hole by lifting and dropping a chisel bit. Syn: churn drill spudding driller In petroleum production industry, one who uses a lightweight, portable drilling rig (spudder) for the drilling of shallow wells, or a regular cable drilling rig to drill the first few feet of a well. Also called spudder or spud driller. Syn: spud driller spudding drum In a churn drill, the winch that controls the drilling line. Nichols, 1 spudding tool Tool used to begin a borehole in earthy materials with a diamond or rotary drill; also, a drilling tool used by a cable tool or churn drill. Long 3057

spud drill See: churn drill spud driller See: spudding driller spud-in See: spud spuds On a dredge, steel tubes pointed at the bottom and provided with lifting tackle at the top that are used to hold and to move the dredge. Nichols, 2 spud setter A mine surveyor. See also: spud spud well On a dredge, a pair of guide collars for a spud. Nichols, 1 spur a. A brace or prop. See also: sprag b. A small vein branching from a main one. AGI c. A rock ridge projecting from a sidewall after inadequate blasting. Nichols, 1 d. A relatively short and small vein of quartz that cuts across the bedding, in contrast to a saddle reef that more or less follows the bedding. Nelson spur-end facet See: triangular facet spurrite A monoclinic mineral, Ca5 (SiO4 )2 (CO3 ) ; dimorphous with paraspurrite; forms light gray granular masses resembling limestone; at Velardena, Durango, Mexico; Scawt Hill, Ireland; Luna County, NM; and Crestmore, CA. spurt Forest of Dean. A disintegrated stone. 3058

spur track In railroading, a short sidetrack connecting with the main track at one end only. Standard, 2 spur valley A short branch valley. Nichols, 1 square A term used in the slate industry with reference to roofing slate. A square is a sufficient number of any size to lay 100 ft2 (9.29 m2 ) of roof, allowing the standard 3-in (7.62-cm) lap. The estimated weight of a square of 1/4-in (6.4-mm) slate is 1,000 lb (454 kg). square drill collar A long stabilizer of rectangular shape that when used properly gives a super-packed-hole effect. Square drill collars are made primarily from 30-ft (9.14-m) steel bar stock with a diagonal measurement greater than the hole diameter in which the collar will eventually be used. This collar has proved successful in controlling rapid directional and deviational changes in wells drilled in a disturbed-belt-type area. API, 2 square-mile-foot A unit of measure representing the volume of water 1 ft (0.3 m) deep over an area of 1 mile2 (2.6 km2 ). See also: acre-foot Hammond square set A set of timbers used to provide support in a stope or an underground mine. Each timber set consists of a vertical post and two horizontal members known as a cap and girt. The timber ends are sawed to allow adjoining timbers to interlock. They are framed at mutual right angles, and when joined with other sets form a continuous timber framework that conforms to the irregular shape of the stope. The posts are 6 to 7 ft (1.83 to 2.13 m) high, while the caps and girts are 4 to 6 ft (1.22 to 1.83 m) long. Caps and girts are placed on top of the posts, a line of caps being at right angles to a line of girts. Square sets vary in dimensions at different mines, but in general should give a clear opening of at least 5 ft (1.52 m) each way between posts to afford sufficient working space in the stope, and a clear height of 6-1/2 ft (1.98 m) is about the minimum height desirable. This system of timber support can be adapted to large and irregular orebodies resulting in an elaborate network extending the full height and width of a stope. square-set and fill 3059

See: square-set stoping square-set block caving A method of block caving in which the caved ore is extracted through drifts supported by square sets. A retreating system is adopted. Nelson square-set slicing See: top slicing and cover caving square-set stoping A method of stoping in which the walls and back of the excavation are supported by a system of interlocking framed timbers (square set). A square set of timber consists of a vertical post and two horizontal members set at mutually right angles. The mining process is slow and only enough ore is excavated to provide room for installation of each successive set of timber. The stopes are usually mined out in floors or horizontal panels, and the sets of each successive floor are framed into the top of the preceding floor. Syn: alternate pillar and stope; overhand vertical slice; underhand vertical slice. CF: backfilling system square-set system A method of mine timbering in which heavy timbers are framed together in rectangular sets, 6 to 7 ft (1.83 to 2.13 m) high, and 4 to 6 ft (1.22 to 1.83 m) square, so as to fill in as the orebody is removed by overhand stoping. Webster 3rd square-set underhand See: square-set stoping square thread a. A screw thread the cross section of which is square. Long b. A robust type of screw thread that can transmit thrust in both directions. Hammond square work See: sublevel stoping square work and caving See: sublevel stoping 3060

squat lads! Fall flat down on the floor. In the early days of coal mining, igniting the gas was a very common thing; so, whenever an explosion took place, the colliers shouted to one another, "Squat, lads!" Fay squealer A shot that breaks the coal only enough to allow the gases of detonation to escape with a whistling or squealing sound; also called a whistler. Zern squeal-out Arkansas. See: seam-out; squealer. squealy coal Arkansas. Seamy coal from which the powder gases escape with a squealing sound. Fay squeeze a. A crushing of coal or other materials with the roof moving nearer to the floor, due to the weight of the overlying strata. Lewis b. The settling, without breaking, of a mine roof over a considerable area of workings. Also called creep; crush; pinch; nip. c. The effect of the closure of stope walls on supports placed between them. Spalding d. A passageway in a cave that is very narrow and can be passed by a person only with great difficulty. AGI e. Applied to sections in coal seams where they have become constricted by the squeezing in of the overlying or underlying rock as a result of pressure during folding or other movements. AGI f. A pinch of a vein in passing through hard bands of rock. Gordon g. To inject a grout into a borehole under high pressure. Long h. The plastic movement of a soft rock in the walls of a borehole or mine working that reduces the diameter of the opening. Long i. Pumping cement back of casing under high pressure to block off or re-cement channeled areas. Wheeler, R.R. j. The rapid or gradual closing of a mine working by the displacement of weak floor strata from beneath supporting pillars into adjacent mine rooms. See also: want squeezer A mine tub controller that acts by squeezing the tub or the wheels. Mason squeeze riveter A single-stroke, compressed-air cylinder for closing rivets through the medium of a toggle mechanism. Hammond 3061

squeezing The slow increase in weight on pillars or solid coal eventually resulting in such things as crushing of the coal, heaving of the bottom, and the driving of pillars into soft floor or top. The cause normally is leaving pillars or other supports which, after considerable area is opened up, prove to be inadequate, permitting the top to settle gradually with transfer of the weight to active places and solid coal. Coal Age, 3 squib a. See: electric squib b. A thin tube filled with black powder, forming a slow-burning fuse to explode a stemmed charge of black powder. BS, 12 c. A small charge of powder exploded in the bottom of a drill hole, to spring the rock, after which a heavy shot is fired. A springing shot. d. In well boring, a vessel, containing the explosive and fitted with a time fuse, that is lowered into a well to detonate the nitroglycerin charge. e. A firing device that will burn with a flash which will ignite black powder. Nichols, 1 squib shot A blast with a small quantity of high explosives fired at some point in a borehole for the purpose of dislodging some foreign material that has fallen into it. Fay squinted vein Derb. A mineral vein cut by a dike and thereby thrown out of alinement on the two sides of the dike. Arkell squirrel cage fan A centrifugal blower with forward-curved blades. Strock, 2 squirrel-cage motor An alternating current electric motor with many applications. The rotor is made of strong parallel copper or aluminum bars on the perimeter, joined to end rings of the same metal. Hammond squotting A stage in the heating of clay when so much of the material has fused that the mass begins to lose its shape and becomes viscous. See also: fusion of clay; vitrifying. Nelson stab

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a. To guide a pipe, casing, or drill rod so that the threads will engage properly. Long b. To recover a drill tool lost in a borehole by using a spear-shaped or pointed fishing tool. Long c. In adding to a drill string, the action of lining up and catching the threads of the loose piece. Nichols, 1 stability a. The resistance of a structure, slope, or embankment to failure by sliding or collapsing under normal conditions for which it was designed; e.g., bank stability and slope stability. See also: bank slope stability b. In thermodynamics, an equilibrium state to which a system will tend to move from any other state under the same external conditions. AGI stability series A grouping of minerals arranged according to their persistence in nature; i.e., to their resistance to alteration or destruction by weathering, abrasion during transportation, and postdepositional solution; e.g., olivine (least stable), augite, hornblende, biotite (most stable). The most stable minerals are those that tend to be at equilibrium at the Earth's surface. Syn: order of persistence stabilized coupling A rod coupling built up to reaming-shell size by welding on an abrasion-resistant metal, applied in ridges parallel to the long axis of the drill rod. Long stabilized tray conveyor See: over-and-under conveyor stabilizer a. A hardened, splined bushing, sometimes freely rotating, slightly larger than the outer diameter of a core barrel. Also called ferrule; fluted coupling. Long b. A misnomer for guide rod. Long c. Any powdered or liquid additive used as an agent in soil stabilization. See also: processing stable a. Not readily decomposed or deformed. CF: unstable b. A short drivage, room, or space excavated at the end of a longwall face to accommodate a coal cutter or cutter loader. The stable provides room for turning the machine where this is necessary, and also exposes a buttock for the machine to start its cut across the face. Nelson stable gravimeter 3063

An instrument that uses a high order of optical and/or mechanical magnification so that an extremely small change in the position of a weight or associated property can be accurately measured. AGI stable hole conveyor A short belt or other conveyor for use in stables in advance of the longwall face. The conveyor is usually about 18 in (46 cm) wide and driven at the tail end by a combined electric motor and drive pulley. The unit can be transported by sliding on steel skids, and is useful where coal or stone has to be moved short distances in confined spaces. See also: shortwall stable isotope A nuclide that does not undergo radioactive decay. Lyman stable lead Any of the nonradioactive isotopes of lead. Handbook of Chemistry and Physics, 2 stable relict A relict mineral that was not only stable under the conditions prevailing while it was formed but also under newly imposed conditions of metamorphism. CF: unstable relict stack a. To stand and rack drill rods in a drill tripod or derrick. Long b. Chock; a chock built of old timber. Mason c. A shaft furnace. d. Any structrue or part thereof that contains a flue or flues for the discharge of gases. See also: inwall stack effect The impulse of a heated gas to rise in a vertical passage, as in a chimney, a small enclosure, or building. Syn: chimney effect Strock, 2 stacker a. A conveyor, mounted on a long steel boom, for carrying tailings beyond the stern of a gold or tin dredge to avoid silting it up. Nelson b. A machine for blending ore before processing. c. A conveyor adapted to piling or stacking bulk materials, packages, or objects. d. With a blending system, the stacker operates over the stocking conveyor in a manner similar to a wing belt tripper to build layered piles or beds of material parallel to the stocking conveyor. See also: boom conveyor; portable conveyor; wing belt tripper; apron conveyor; belt conveyor; flight conveyor; portable conveyor. e. One who controls 3064

conveyor belt moving molds containing molten lead through water spray to stamping and discharge tables. DOT f. One who stacks coal, etc. Fay g. Leic. A miner who looked after the unloading of the coal on the bank, on behalf of the miners, in the earlier days of mining. Fay h. A machine for blending ore that beds the ore before reclaiming for processing. stack height The height of a convector enclosure measured from the bottom of the enclosure to the top of the outlet. Strock, 2 stacking fault A type of "plane defect" in a crystal structure, caused by one or more closest-packed layers added to or removed from a normal cubic closest-, hexagonal closest-, or other regular closest-packed sequence. stadia a. A surveying technique or method using a stadia rod in which distances from an instrument to the rod are measured by observing through a telescope the intercept on the rod subtending a small known angle at the point of observation, the distance to the rod being proportional to the rod intercept. The angle is usually defined by two fixed lines in the reticle of the telescope. AGI b. See: stadia rod c. An instrument used in a stadia survey; esp. an instrument with stadia hairs.---Pl: stadias. The term is also used as an adj. in such expressions as stadia surveying, stadia distance, and stadia station. AGI stadia hairs Horizontal cross hairs equidistant from the central horizontal cross hair; esp. two horizontal parallel lines or marks in the reticle of a transit telescope, arranged symmetrically above and below the line of sight, and used in the stadia method of surveying. Syn: stadia wires stadia rod A graduated rod used with an instrument having stadia hairs to measure the distance from the observation point to the place where the rod is positioned. Syn: stadia stadia surveying The process of measuring distances and elevations by observing through a telescope the distance intercepted on a rod between two horizontal cross-hairs. These hairs are carried on the same ring as the regular horizontal crosshair, and are equidistant from it. Zern 3065

stadia tables Mathematical tables from which may be found, without computation, the horizontal and vertical components of a reading made with a transit and stadia rod. stadia wires See: stadia hairs stadia work Tacheometric survey, in which points sighted from a survey station are oriented as with a theodolite, and their distance is read by means of a vertically held leveling staff on stadia wires. Pryor, 3 staff a. A surveyor's leveling rod. Standard, 2 b. An iron puddler's rabble or rabbler. Fay staff gage Graduated scale marked on a rod or a metal plate, or on the masonry of a bridge pier or similar structure, from which the depth of water in a canal, dock, or river can be read. Hammond staff hole A small hole in a puddling furnace through which the puddler heats the staff. See also: staff staff man The person who carries a leveling staff for a surveyor. See also: target rod; telemeter rod. Hammond Staffordian Series The so-called transition group of the British Coal Measures, between the Middle and Upper Coal Measures in the Carboniferous System. They include the Newcastle-underLyme Group and the Etruria Marl, and the Blackband Group in north Staffordshire, England. CTD staflux

3066

A material made by sintering together lumps of limestone and certain kinds of iron oxide, such as iron ore or mill scale, at a temperature of 1,450 degrees C in a rotary furnace. Though fusion does not occur, the iron oxide rapidly penetrates the limestone completely and forms dicalcium ferrite. Osborne stage a. A landing, such as in a shaft mine. b. A platform on which mine cars stand. c. A step in a process. d. A time-stratigraphic unit next in rank below a series and corresponding to an age; it generally consists of several biostratigraphic zones. It is the most important unit for long-range correlation. stage addition In flotation, this refers to deliberate use of insufficient reagent in the early part of the treatment to increase selectivity of conditioning, followed by further addition at a later point in the process. Pryor, 4 stage compression See: compound compression stage crushing A method of crushing in which there is a series of crushers, each one crushing finer than the one preceding. stage grinding Comminution in successive stages. Pryor, 4 stage loader See: feeder conveyor stage plumbing A precise method of orienting underground workings in which plumblines are transferred down a deep shaft in stages of 400 to 600 ft (120 to 185 m). While shaft sinking is in progress, the lines can also be employed to orient the shaft itself and to keep it plumb. BS, 7 stage pumping

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Draining a mine by means of two or more pumps placed at different levels, each of which raises the water to the next pump above or to the surface. stage treatment In mineral processing, development of the desired condition of the particles by defined states, such as comminution to successively fine sizes (possibly coupled with staged concentration or gangue elimination) between such stages of communition. Pryor, 3 stage winding Winding, usually in compound shafts, where the wind is divided into two or more stages, and underground winding engines are installed to deal with the lower stages. Sinclair, 5 stage working A system of working minerals by removing the strata above the beds, after which the various beds are removed in steps or stages. staggered blastholes When shot firing in thick coal seams, two rows of holes may be necessary. These are usually staggered to a triangular pattern to distribute the burden. A similar pattern is often adopted in quarry wellhole blasting. Nelson staggered holes To arrange boreholes in a row, in such a manner that those in one row are placed opposite the spaces between the boreholes in the next row. Long stag hole Usually a short hole drilled, charged, and fired to shatter the rock near the collars of the cut holes. Nelson staging a. A temporary flooring or scaffold, or platform. Zern b. One or more working platforms, fixed at defined levels in deep trenches or similar excavations, on to which excavated earth is thrown by shovel. Hammond stained stone

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A gemstone with color altered by a coloring agent, such as a dye, or by impregnation with a substance, such as sugar, followed by chemical or heat treatment, which usually produces a permanent color; e.g., green chalcedony. CF: burnt stone stainierite See: heterogenite stainless steel Iron-base alloy containing enough chromium to confer a superior corrosion resistance. ASM, 1; Newton, 1; CTD; Camp stains Inclusions and intergrowths in mica arising from foreign materials, resulting in a partial or total loss of transparency. Skow stake a. Grubstake. b. A pointed piece of wood driven into the ground to mark a boundary, survey station, or elevation. c. See: sprag d. An iron peg used as power electrode to transfer current into the ground in electrical prospecting. This term is also used to include all power and search electrodes, such as iron pegs, copper coils, and copper screens; also, a station marker used by field parties. AGI e. A permanent interest, as in an enterprise or a mine. staking out The physical act of locating a lode or placer mining claim. stalactite A conical or cylindrical mineral deposit that hangs from the ceiling of a cave. See also: stalagmite stalagmite A conical or cylindrical mineral deposit that is developed upward from the floor of a cave by the action of dripping water. See also: stalactite Syn: dropping stones stalagmometer

3069

An apparatus for determining surface tension. The mass of a drop of a liquid is measured by weighing a known number of drops or by counting the number of drops obtained from a given volume of the liquid. Lowenheim stalch Eng. A mass of ore left in a mine. stall a. A narrow coal drivage in pillar-and-stall. See also: narrow stall; stallman. Nelson b. A working place at the coal face; a term associated with narrow workings. Mason stall-and-breast See: room-and-pillar stall-and-room working A pillar method of working a relatively thick coal seam by a system of compartments; a modification of pillar-and-stall. Nelson stalling angle The blades of axial-flow fans are of aerofoil section, which when inclined at a small angle (known as the angle of attack) to the air stream produce a large lift or raising force for a small drag or retarding force. The lift force is the useful one which gives the thrust to the air in an axial-flow fan. The lift increases with increase in the angle of attack until a point is reached when the lift begins to fall. This angle is the "critical" or "stalling angle." Syn: critical angle stallman A collier who works at the face of a narrow stall or a longwall stall. The collier is paid according to a pricelist of so much per ton of coal loaded out and for other work, such as timbering. A stallman usually has another miner alongside. Nelson stall roasting The roasting of ore in small enclosures of earth or masonry walls. The enclosures are called stalls and may be open or closed. Fay stamler See: feeder breaker 3070

stamp a. To break up ore and gangue by machinery, for washing out heavier metallic particles. b. A heavy pestle raised by water or steam power for crushing ore. A stamp in which the blow of the pestle is caused by its mere weight is called a gravity stamp. Webster 3rd stamp battery See: stamp mill stamp duty The amount of ore (tons) that one stamp will crush in 24 h. stamper box A stamp-mill mortar box. Fay stamp hammer A power hammer that moves vertically. Webster 3rd stamp head A heavy and nearly cylindrical cast-iron head fixed on the lower end of the stamp rod, shank, or lifter to give weight in stamping the ore. The lower surface of the stamp head is generally protected by a cheese-shaped shoe of harder iron or steel that may be removed when worn-out. These shoes work upon dies of the same form laid in the bottom of the mortar or stamper box. See also: stamp stamping a. Reducing to the desired fineness in a stamp mill. The grain is usually not so fine as that produced by grinding in pans. Fay b. A general term covering almost all press operations. It includes blanking, shearing, hot or cold forming, drawing, bending, and coining. ASM, 1 c. A process for application, by hand or by machine, of decoration to pottery ware; a rubber stamp with a sponge backing is used. Stamping is particularly suitable for the application of backstamps and for some forms of gold decoration. See also: backstamp stamping maundrill Leic. A heavy pick. stamp mill 3071

An apparatus, and the building containing it, in which rock is crushed by descending pestles (stamps), operated by water power or steam power. Amalgamation is usually combined with crushing when gold or silver is the metal sought, but copper, tin, and other ores are stamped to prepare them for dressing. The technique is obsolete. Syn: stamp battery stamp shoe The heavy, chilled-iron casting, attached to the lower end of a stamp piston, which does the actual crushing of rock in a stamp mill. It drops on a round steel block called a die. Weed, 2 stampsman Person who attends or operates a stamp or stamp battery. Fay stampwork A term used in the Lake Superior region for rock containing disseminated native copper. stanchion a. A vertical prop or strut. Zern b. A support or post of iron or wood. Crispin stand a. Two or more lengths of drill rod or casing coupled together and handled as a unit length as they are taken from a borehole and set upright in a drill tripod or derrick. See also: double; forble; treble. Long b. A drill floor. Long c. To allow a cement slurry to remain undisturbed in a borehole until it hardens or sets. Long d. To set a string of casing in a borehole. Long standage a. Reservoir or storage capacity, said of water and of mine cars. Mason b. See: sump c. The capacity of a sump or lodge. BS, 10 d. See: lodge standage room A length of roadway provided near a shaft bottom to stock loaded mine cars and/or empty cars: (1) during peak hours when the coal reaches the pit bottom at a faster rate than the shaft can wind; and (2) during emergency periods, such as plant breakdown at the surface, thus permitting coal production to continue. In general, the standage room accommodates 45-min to 1-h winding capacity. See also: bunker conveyor; bunkering capacity. Nelson 3072

standard air density In mine ventilation, the standard density of air for mine ventilation work is considered to be 0.075 lb/ft3 (1.2014 kg/m3 ). This is based upon the weight of 1 ft3 (0.028 m3 ) of dry air at 70 degrees F (21.1 degrees C) at a sea-level pressure of 29.9 in (759 mm) of mercury. standard bit A bit the size and design of which are as specified in standards accepted by the drilling industry. Long standard conditions In refrigeration, an evaporation temperature of 5 degrees F (-15 degrees C), condensing temperature of 86 degrees F (30 degrees C), liquid temperature before the expansion valve of 77 degrees F (25 degrees C), and suction temperature 14 degrees F (-10 degrees C). Strock, 2 standard copper Practically any brand of 96%, or higher, fineness. standard core bit See: standard bit standard electrode reference Electrode used as a standard in measurements of electrode potential, because its potential is constant and reproducible; used for pH measurements, polarographic analysis, etc. standard ignition test A method developed for testing coal dust to obtain the limits of explosibility. Rice, 2 standard impinger For many years, the Greenburg-Smith impinger was the routine dust sampling instrument in this country. It is still relied upon as a standard, but because of its size and weight, is little used underground today. Hartman, 1 standard lay See: regular lay 3073

standard mineral See: normative mineral standard mix Concrete mixed in the proportions of 1 part cement, 2 parts sand, and 4 parts coarse material. See also: aggregate; cement. Nelson standard of ventilation An adequate amount of ventilation to dilute and render harmless all noxious and flammable gases to such an extent that all roads and workings in a mine shall be kept in a fit state for working or passing therein. Mason standard parallel a. A parallel of latitude that is selected as a standard axis on which to base a grid system; specif. one of a set of parallels of latitude (other than the base line) of the U.S. Public Land Survey system, passing through a selected township corner on a principal meridian, and on which standard township, section, and quarter-section corners are established. Standard parallels are usually at intervals of 24 miles north or south of the base line, and they are used to limit the convergence of range lines that intersect them from the south so that nominally square sections and townships can be laid out. Syn: correction line b. A parallel of latitude that is used as a control line in the computation of a map projection; e.g., the parallel of a normal-aspect conical projection along which the principal scale is preserved. AGI c. A parallel of latitude on a map or chart along which the scale is as stated for that map or chart. AGI standard penetration test a. A soil-sampling procedure to determine the number of blows by a drive hammer, freely falling a distance of 30 in (0.76 m) per blow, needed to drive a standard sampling spoon 1 ft (0.3 m). The first 6 to 7 in (15.24 to 17.78 cm) of penetration is disregarded, but the blows required to drive the sample the ensuing foot are counted. Long b. See: penetration test standard plow The original coal plow; a heavy double-ended machine with fixed blades. Its length is 61/2 ft (1.98 m); its height ranges from 14 to 31 in (35.6 to 78.7 cm). The depth of cut can be varied from 2 to 6 in (5.1 to 15.2 cm). The rapid plow has evolved from this relatively slow-moving machine. Nelson standard pressure 3074

a. A term applied to valves and fittings suitable for a working steam pressure of 125 psi (862 kPa). Strock, 1 b. See: normal pressure standard rig a. An archaic term for a cable-tool drilling rig. AGI b. A common misnomer for cabletool rig, churn-drill rig. Long standard section A geologic section showing as completely as possible a sequence of all the strata in a certain area, in their correct order, thus affording a standard for correlation. It supplements (and sometimes supplants) the type section, esp. for time-stratigraphic units. AGI Standard Temperature and Pressure Atmospheric pressure of 760 mm of mercury, at 0 degrees C. Pryor, 3 standard tin Tin of 99.75% or greater purity. Bennett standard wire gage Gage number defining the diameter of wire. Abbrev.: SWG. Pryor, 3 standby face A spare conveyor face, of normal length, that could be worked should another face cease production due to faults, washouts, roof collapse, water, gas, or any other unforeseen impediment. Syn: spare face Nelson standdown Gr. Brit. The sending of miners home because they cannot be usefully employed due to any reason outside the control of the management. In some cases, coal mining awards confine this right to certain occurrences, e.g., breakdown of plant or machines. Nelson standing a. Used by drillers to denote that work has been stopped for a considerable time. Long b. Drill rods or casing stacked vertically in the drill tripod or derrick. Long standing column 3075

The column of drilling liquid left in the hole when the drill tools have been removed. Long standing fire A fire in a mine continuing to smoulder for a long time, often many years. Fay standing gas A body of combustible gases known to exist in a mine, but not in circulation; sometimes fenced off. Fay standing shot The result of a small or undercharged shot wherein the coal is loosened so that it is easily mined by pick. The term is a misnomer, as it applies to the result and not the "shot" or "charge." Fay standing time Gr. Brit. The period when face workers are idle due to the lack of empty cars, etc. Payments are made to miners on piecework for time lost. See also: lying money stand of drill rods See: stand standoff a. A short length of core attached to and left standing upright in the bottom of the borehole when the core barrel is pulled. Long b. On taper-tool or drillpipe joints, the space between the pin- and box-thread shoulders before wrenching up. Long standpipe a. A relatively short length of pipe driven into the upper soillike portion of the overburden as the first step of collaring or spudding-in a borehole. Also called conductor; conductor pipe. Long b. A short piece of pipe wedged or cemented into a borehole after completion to act as a marker and keep collar free of cave. CF: surface string standpiping Driving pipe deep enough through overburden to keep soil, sand, etc., out of a borehole. See also: standpipe 3076

stands Connected joints of drill pipe racked in the derrick while changing the bit. Wheeler, R.R. stank a. To make watertight; to seal off; an airtight and watertight wall against old mine workings. See also: seal; sealed-off area. Nelson b. A small cofferdam constructed of timber and made watertight with clay. Hammond c. See: stanking stanking a. A watertight stopping or bulkhead. BS, 10 b. The application of a waterproofing material to a stopping or bulkhead. BS, 10 Stanley compensating diaphragm A specially designed theodolite used as a direct reading tacheometer. See also: Beaman stadia arc stanley header See: header stannary a. A tin mine or tin works. Webster 2nd b. One of the regions in England containing tinworks and formerly placed under jurisdiction of special courts. Usually used in plural. Webster 3rd stannary courts Eng. Courts in Cornwall and Devonshire for the purpose of regulating the affairs of tin mines and tin miners. stannatores An early name applied to Cornish tin miners. stanniferous Relating to or containing tin; as, stanniferous ore. stannine 3077

See: stannite stannite a. A tetragonal mineral, Cu2 FeSnS4 ; zinc may replace iron; tannite group; metallic; in granular masses in veins associated with cassiterite. Syn: tin pyrites; bell-metal ore. b. The mineral group briartite, cernyite, famatinite, hocartite, kuramite, luzonite, permingeatite, pirquitasite, sakuraiite, and stannite. c. Impure cassiterite. Syn: tin pyrites; stannine. stannopalladinite A hexagonal mineral (Pd,Cu)3 Sn2 (?) . stannous chloride See: salt of tin stannum See: tin stantienite A black variety of retinite having a very high oxygen content (23%). Syn: black amber Stanton diagram Historically, a plot of the airflow friction coefficient against the Reynolds number is referred to as a Stanton diagram. staple a. A shaft that is smaller and shorter than the principal one and joins different levels. Webster 3rd b. An internal shaft connecting two coal seams. Also called staple pit. CF: winze staple shaft a. An underground shaft, which does not penetrate to the surface. Fraenkel b. A relatively small vertical pit connecting a lower seam to an upper seam. It corresponds to a rise or winze in metal mining. A staple shaft is an important drivage in horizon mining and may be used for dropping coal or stowing dirt to a lower level. It is often equipped with a spiral chute or an auxiliary winder system with a single cage and counterweight. See also: subincline 3078

star In minerals, the presence of needlelike oriented inclusions aligned along crystallographic axes, generally in the plane normal to the c axis in the hexagonal and trigonal crystal systems. Syn: asteriated star antimony Refined metallic antimony characterized by crystalline patterns resembling stars or fern leaves on its surface. Also called star metal. Webster 3rd starch Used as depressant in flotation process. Alkaline starch (starch dissolved in dilute sodium hydroxide) is a flocculating agent used in purifying the water in coal-cleaning plants. Also known as amylum. Pryor, 3 star drill A tool with a star-shaped point used for drilling in stone or masonry. Crispin star facet Small triangular facet situated between the bezel facets and the table on the crown of an American (Tolkowski theoretical) brilliant-cut diamond. star feeder A rotating feeder consisting of a horizontal shaft fitted with radial blades running within a close-fitting cylindrical chamber provided with an inlet and an outlet. Also called star gate; star valve (undesirable usage). BS, 5 star garnet Variant of almandine. Hey, 1 starkeyite A monoclinic mineral, MgSO4 .4H2 O ; rozenite group. Named for the Starkey Mine, Madison County, MO. Syn: leonhardtite Starlite Trade name given by Kunz to artificially-colored blue zircon from Thailand. English 3079

star metal See: star antimony star quartz A variety of quartz containing within the crystal whitish or colored starlike radiations along the diametral planes. The asterism is due to the inclusion of submicroscopic needles of another mineral arranged in parallel fashion. In star blue quartz in Virginia and Texas, the other mineral is rutile. See also: asteriated quartz star reamer A star-shaped tool for regulating the diameter of, or straightening, a borehole. star ruby A semiopaque to semitransparent asteriated variety of ruby normally having six chatoyant rays. CF: corundum cat's eye star sapphire A semiopaque to semitransparent asteriated variety of sapphire normally with six rays resulting from the presence of microscopic crystals (e.g., rutile needles) in various orientations with the gemstone. See also: asteria star stone a. An asteria; esp. a star sapphire. AGI b. Less correctly, any asteriated stone, including even petrified wood containing small starlike figures in its more transparent parts. AGI starter a. A slightly larger drill used for making the beginning of a hole, the remainder of the hole being made with a drill of smaller gage known as a follower. Fay b. Pennsylvania. The miner who ascends to the battery to start the coal to run. See also: battery starter c. Protective equipment to ensure that an electric motor does not receive too high a current when starting. Hammond starter bar A steel reinforcing bar embedded in the concrete and projecting through a construction joint to bind adjoining masses of concrete together. Hammond starting barrel 3080

A short core barrel used to begin coring operations when the distance between the drill chuck and the bottom of the hole, or to the rock surface in which a borehole is to be collared, is too short to permit use of a full 1.5-m-long or 3-m-long core barrel. Long starting casing barrel A short piece of casing to which a casing bit and shell are attached and used under the same conditions as a starting barrel. See also: starting barrel starting sheet A thin sheet of metal used as the cathode in electrolytic refining. ASM, 1 starting submergence In an air lift, the distance below the static head at which the air picks up water. Lewis starvation a. In comminution, avoidance of crowding in the machine by restricting rate of feed. b. In conditioning for flotation, use of threshold quantity of collector agent to aid in selective adsorption by the desired species of mineral. Stassfurt deposits A series of saline minerals, found in the Triassic rocks at Stassfurt, Saxony, Germany, which include halite, anhydrite, kieserite, gypsum, and boracite. stassfurtite A massive variety of boracite found in Germany. It resembles a fine-grained white marble; sometimes has a subcolumnar structure. Fay; CTD statement of performance A statement describing the scope and duty of a plant in terms, e.g., of the tonnage of coal treated per hour, the processes used, the separations effected and sizes produced; sometimes also used to express the results of plant operation. BS, 5 state mine inspector See: inspector; mine inspector. state point 3081

The psychrometric properties of air at given conditions, e.g., dry bulb temperature, wet bulb temperature, and barometric pressure. Hartman, 2 stathmograph An apparatus that records automatically, in the form of a graph, the loss of weight during the whole reduction of iron ores. Osborne static air mover See: air mover statically determinate frame A structural frame in which the bending moments and reactions can be determined by the laws of statics alone. Hammond statically indeterminate frame A redundant frame in which the bending moments and reactions cannot be calculated from statical equations alone. See also: perfect frame Hammond static balance A condition of rest created by inertia (dead weight) sufficient to oppose outside forces. Nichols, 1 static efficiency Is calculated in the same way as fan efficiency, but using a reading of static pressure at some point instead of total pressure. Was formerly widely quoted, and is still used to some extent, in relation to mine fans. See also: fan efficiency static E.P. The electrode potential measured when no current is flowing between the electrode and the electrolyte. Lowenheim static grizzly A grizzly in the form of a stationary bar screen, often improvised from bars or rails set longitudinally, without cross bars. If used as a chute it has a slope of 35 degrees to 45 degrees . It may allow suitable pieces of coal or ore to pass over, and the unwanted small sizes drop through, or it rejects oversize pieces while allowing suitable material to drop through. See also: power grizzly 3082

static head a. The height of a standing column of water as measured from the bottom of a borehole upward. Sometimes expressed in units of weight as measured at the bottom of the borehole. Long b. In an air lift, the distance from the surface or top of the well casing to the normal surface of the water when not pumping. Lewis c. The sum of the suction and discharge heads. Carson, 1 d. See: hydrostatic head; static level. static level The water level of a well that is not being affected by withdrawal of ground water. AGI static load a. The basal pressure exerted by the weight of a mass at rest, such as the load imposed on a drill bit by the weight of the drill-stem equipment or the pressure exerted on the rocks around an underground opening by the weight of the superimposed rocks. Syn: dead load b. A load that is at rest and exerts downward pressure only, such as a hydrostatic load. Nichols, 1 static metamorphism A variety of regional metamorphism brought about by the action of heat and solvents at high lithostatic pressures, not at pressures induced by orogenic deformation. See also: load metamorphism CF: thermal metamorphism static moment The static moment of a section about an axis, Y, is also termed the first moment of the area about the axis. It is the sum of the products obtained by multiplying each component of an area, A, by its distance, X, from Y. See also: moment of inertia static penetration test A penetration test in which the testing device is pushed into soil with a measurable force, as distinct from a dynamic penetration test in which the testing device is driven into the ground by blows from a standard hammer. See also: penetrometer; soil. Hammond statics That branch of mechanics dealing with the relations of forces that produce equilibrium among material bodies. Webster 3rd static switch 3083

A device giving contactless control of a circuit; e.g., a transistor, thyratron, saturable reactor, etc. NCB static tube A static tube has a shaped, solid nose, on the downstream side of which a number of small holes are positioned around the circumference. The holes are so placed that the pressure in the tube is that of the undisturbed airstream. Unlike the Pitot tube, the measured pressure is affected considerably both by the position of the stem of the tube in relation to the pressure holes, and by the distance between the holes and the nose tip. The static tube is considerably more sensitive to yaw than is the Pitot tube. See also: Pitot tube; Pitot-static tube. Roberts, 1 static water level The level of water in a well or borehole when pumping is not in progress. BS, 10 station a. See: underground station; tank station. b. A reference point in surveying, marked at the surface by a metal plate set in concrete, or by a plug drilled into the roof of an underground working. Pryor, 3 c. A length of 100 ft (30.5 m), measured along a given line, which may be straight, broken, or curved. Seelye, 2 d. Any point on a straight, broken, or curved line whose position is indicated by its total distance from a starting point, or zero point. For example, station 4+47.2 identifies a point 447.2 ft (135.3 m) from the starting point, the distance being measured along a given line. e. A location on a conveyor system where bulk material is received or discharged. f. Any one of a series of stakes or points indicating distance from a point of beginning or reference. g. A setup point; i.e., a marked point on the ground, over which an instrument is to be placed. stationary bar screen A large-capacity screening or sorting appliance for coal or ore. It consists of a series of heavy metal bars arranged side by side and spaced at a definite distance apart. The bars are set at an angle so that material delivered at the upper end will just slide, and chutes are arranged to receive oversize at the lower end and undersize passing between the bars. The stationary bar screen is still used at many small mines. See also: Bradford breaker; resonance screen; screen. Nelson stationary block The relatively undeformed rocks beneath the plane of an overthrust fault. See also: autochthon stationary dredge 3084

a. A dredge that is not self-propelled, the dredged material from which is discharged into either a hopper barge or a pipeline. Hammond b. A fixed vessel with equipment for digging, washing, and concentrating alluvial deposits. See also: dredge stationary engine An engine located on a fixed foundation, as distinguished from a portable engine. Crispin stationary equipment Stationary equipment is installed in a given location and is not moved from that location in performing its function. This includes equipment such as substations, pumps, and storage-battery charging stations. stationary grizzly The simplest of all separating devices and the cheapest to install and maintain. It consists of a series of fixed bars or rails spaced the required distance apart in order that the "undersize" may drop through. The use of a stationary grizzly is limited to coarse screening of dry material (aperture 2 in or 5.1 cm and larger), although it is sometimes used with openings as small as 3/4 in (1.9 cm), the efficiency dropping off in proportion. It is not satisfactory for moist or sticky material. Pit and Quarry stationary inner-tube core barrel See: rigid-type double-tube core barrel stationary jaw The fixed jaw of a safety clamp or wrench. Syn: stationary slip CF: anvil stationary mass In some seismometers, a heavy weight, either suspended or supported, that, because of inertia, tends to remain quiescent during an earthquake. Syn: steady mass stationary-piston drive sampler A piston-type sampler in which the position of the piston relative to the sample remains constant during the sampling operation. Long stationary slip See: stationary jaw 3085

station foreman In metal mining, a laborer who supervises the haulage and handling of ore, timber, and mining supplies at a shaft station. DOT stations Permanently marked points on the centerline of a tunnel . These stations may be outside of the tunnel and used for projecting the centerline into the tunnel, or they may mark the centerline inside the tunnel. Stauffer station yards haul Equals the number of cubic yards multiplied by the number of 100-ft (30.5-m) stations through which it is moved. Nichols, 1 statistical uniformity A term describing that variation in quality of materials of manufactured goods that is stable and determinate, so that statistical analysis and prediction can be applied to it. See also: representative sample; level of control. Hammond statistics The collection, tabulation, and study of numerical facts and data. In industry, statistics indicate trends that would be almost impossible to establish by other means. The statistical method is useful in: (1) estimating the real value of work done, goods, or machines in terms of useful service and maintenance costs; and (2) estimating and forecasting profits and markets. See also: parameter stator In a torque converter, a set of fixed vanes that change the direction of flow of fluid entering the pump or the next stage turbine. Nichols, 1 statuary marble A fine-grained saccharoidal marble used by sculptors. The best qualities are pure white and free from markings. staurolite A monoclinic mineral, Fe2 Al9 Si4 O22 (OH)2 ; pseudo-orthorhombic; Mohs hardness, 7.5; a common accessory in medium-grade regional metamorphic rocks; may be of gem 3086

quality; cruciform twins called fairy crosses. Syn: staurotide; cross-stone; grenatite; fairy stone; lucky stone. stauroscope A type of polariscope used to determine the direction of light polarization in a crystal for accurate measurement of angles of extinction. See also: polariscope staurotide See: staurolite staurotypous In mineralogy, having crosslike markings. Standard, 2 stave a. A ladder step. Zern b. A wedge-shaped section placed around the die of a stamp to take up the side wear. stavrite An obsolete term for a type of biotite amphibolite. stay A diagonal brace or tie bar to stiffen or prevent movement of a structural component. Hammond stay-bolt tap A type of combination reamer and tap used extensively in locomotive-boiler work. Crispin stead S. Wales. Very thin bands of ironstone in coal measures. AGI Stead's reagent An etching reagent, used in metallographic examination of steels, containing 100 mL methyl alcohol, 18 mL water, 2 mL concentrated hydrochloric acid, 1 g copper chloride, and 4 g magnesium chloride. Osborne 3087

steady-flow process A flow process in which none of the variables of flow changes with time. Hartman, 2 steady-head tank In connection with use of moderate pressure hydraulic water (e.g., in classification of ore pulps), a reservoir set above the draw-off points of the system, which maintains a full supply of water at a set height and therefore constant pressure. Pryor, 3 steady mass See: stationary mass steady point A pointed steel bar that can be locked in a clamp, and is used to brace a drill frame against the ground. Nichols, 1 steady-state creep See: secondary creep steady-state velocity The constant maximum detonation velocity achieved by an explosive charge of a given diameter, mixture and density; it is the velocity at which a detonation will sustain itself through a column of explosive. stealite Chiastolite, a variety of andalusite. steamboat rolls Those rolls in an anthracite breaker that are set farthest apart to break the coal into steamboat coal. Standard, 2 steam gas Highly superheated steam. Webster 2nd steam hammer A heavy hammer, moving between vertical guides, actuated by steam pressure. Crispin 3088

steam-hoist man See: hoistman steam infusion The injection of steam into the coal seam by infusion tubes, connected to a small boiler through high-pressure hose pipes, to suppress the dust in situ. The technique and equipment are somewhat similar to water infusion. Owing to technical, safety, and other problems, water infusion is preferred. Nelson steam jet a. A system of ventilating a mine by means of a number of jets of steam at high pressure kept constantly blowing off from a series of pipes in the bottom of the upcast shaft. b. A jet of steam to moisten the intake air current and thus keep the coal dust in the mine wet. Zern steam jet refrigeration A method of cooling involving the use of steam nozzles to reduce the pressure in a water chamber so that the water boils at a low temperature; since heat is drawn from the water, it is thus cooled. Strock, 2 steam main A horizontal pipe for carrying live steam from a boiler to radiators, a steam engine, or other steam consuming device. Crispin steam point See: point steam shovel An excavating machine in which a large dipper is operated by steam power. Used for stripping purposes and in open-pit mining, esp. for iron and coal. A similar shovel is now operated by electricity, gasoline, and diesel engines. Standard, 2 steam shovel mine An opencut mine in which steam shovels or other power shovels are used for loading cars. Hess steam stamp 3089

A crushing machine consisting of a vertical stamp shaft that is forced down to strike its blow, and lifted up preparatory to striking the next, by a steam piston. Fay steam thawing A method of dredging permanently frozen ground in Alaska and the Yukon Territory in which steam is forced through pipes that are fitted with steel points on one end and a driving head on the other end so that the pipes can be hammered into the frozen gravel. Thawing by steam is a slow and costly process. See also: thawing steam winder The most common type of steam winder is the two-cylinder double-acting horizontal engine driving direct on the drum shaft. These engines, which are made with cylinders up to 42 in (1.1 m) in diameter and with a 84-in (2.1-m) stroke, possess the merit of simplicity and ease of control. The two cylinders act on cranks set at 90 degrees to each other and are large enough for either to start the engine from rest against a full load, since one may happen to stop at dead center (i.e., with the piston at the end of its stroke, in which position it can exert no turning moment on the crank). Mason Steart fan A propeller or axial-flow fan developed by Steart in Australia. See also: fan steatite a. A compact, massive, fine-grained, fairly homogeneous talc-rich rock. b. Gray-green or brown massive impure talc that is carved easily into ornamental objects. Syn: lardite; lard stone; soapstone; soap earth. See also: talc steatite talc A relatively pure or high-grade variety of talc suitable for use in electronic insulators, the purest commercial form of talc. Syn: French chalk steatitization Introduction of, alteration to, or replacement by, talc (steatite); esp. the act or process of hydrothermal alteration of ultrabasic rocks that results in the formation of a talcose rock (such as steatite, soapstone, or relatively pure concentrations of talc). AGI Stebinger drum A delicate vertical-angle adjustment for the vernier on the alidade, graduated in hundredths of a revolution. See also: gale alidade CF: tangent screw 3090

steel a. An iron-base alloy, malleable in some temperature range as initially cast, containing manganese, usually carbon, and often other alloying elements. In carbon steel and lowalloy steel, the maximum carbon is about 2.0%; in high-alloy steel, about 2.5%. The dividing line between low-alloy and high-alloy steels is generally regarded as being at about 5% metallic alloying elements. Steel is to be differentiated from two general classes of irons: the cast irons, on the high-carbon side and the relatively pure irons, such as ingot iron, carbonyl iron, and electrolytic iron, on the low-carbon side. In some steels containing extremely low carbon, the manganese content is the principal differentiating factor, steel usually containing at least 0.25%; ingot iron contains considerably less. ASM, 1 b. The borer, consisting of shank, shaft, and bit or cutting edge; used for rock-drilling with drifters or jackhammers. CTD c. In air hammers, the hollow or solid steel bar that connects the hammer with the cutting tool. Nichols, 2 steel arch Curved length of steel, usually of H-section, used for supporting mine roadways. Two-, three-, or four-segment arches are available, with straight leg, splayed leg, horseshoe, or circular design; in double radius or with welded baseplate. See also: Usspurwies arch; Toussaint-Heintzmann arch; steel support; steel ring. Nelson steel band belt A belt of relatively thin carbon or stainless strip steel alloyed and heat treated to withstand continued flexing over pulleys. steel belt Thin, flat, steel belts ranging from 0.008 to 0.035 in (0.02 to 0.09 cm) in thickness and from 7/8 to 8 in (2.2 to 20.3 cm) in width have been successfully used. The pulleys should be faced with a thin layer of cork. Steel belts can be run at speeds as high as 10,000 ft/min (3.0 km/min). It has been claimed that a 4-in (10.2-cm) steel belt will transmit as much power as a 19-in (48.3-cm) leather belt. Crispin steel bit The cutting tool at the end of the drill steel. Various bit shapes are used, the three commonest being the single chisel bit (used only for hand drills); the double chisel bit (used for fairly soft rock), and the cross bit (used for hard rock and for general purposes). See also: tungsten carbide bit; chisel bit; cross-chopping bit. Nelson steel boy

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A youngster who carries drills to the miners, and collects dull drills and sees that they are returned to the blacksmith shop. Fay steel cable A flexible rope, the strands of which are steel wires. See also: cable Long steel-cable conveyor belt A rubber conveyor belt in which the carcass is composed of a single plane of steel cables that acts as a longitudinal tension-carrying member and includes two or more plies of fabric to provide transverse strength and hold the cables together. steel casing A pipe to support the walls of a borehole in loose ground. The casing is secured in position by a concrete block or by the cross beams of the platform. It is driven down from the surface and follows the drilling operation closely or sometimes even precedes the borehole in sand or very loose ground. See also: borehole casing steel centralizer On a wagon drill, a guide to hold the starting steel in proper alignment. Nichols, 2 steel erector A skilled member of a team specially trained to erect steel framed buildings, bridges, and other steel structures. Hammond steel guides Steel rails, rods, or bars fixed in a vertical shaft to guide the cage and prevent it from swinging. See also: fixed guides steel jack a. A screw jack esp. suitable in mechanical mining. Under headers at or near the face, steel jacks or posts are used for upright timbers to be replaced as equipment advances. Also called steel post. Kentucky b. See: sphalerite steelmaking The process of making steel from solid or molten pig iron, with or without admixture with steel scrap. The processes used are the Bessemer, open-hearth, crucible, electric arc, high-frequency induction, and duplex. CTD 3092

steel mill A mill where steel is made, processed, and shaped. Webster 3rd steel needle An instrument used in preparing blasting holes; used before the safety fuse was invented. Fay steel ore A name given to various iron ores and esp. to siderite, because it was supposed to be esp. adapted for making steel by the earlier and direct process. Fay steel plate conveyor See: plate conveyor steel press A machine for compressing molten steel in casting to improve the quality of the product. Standard, 2 steel prop A steel upright or post used to support the nether roof at a longwall or other face. It usually incorporates a yielding device. See also: hydraulic prop; mechanical yielding prop; self-advancing supports. Nelson steel puller A hinged clamp on the bottom of a hand drill. Nichols, 1 steel rectangular shaft supports A shaft support consisting of H-beams, I-beams, angles, and sheeting. The design is somewhat similar to that used for timber. Bolts, rivets, and fastening angles are used to connect and secure the steel members. The fastening angles are riveted to the beams. The addition of galvanized-iron corrugated wall sheets (or laggings) form a secure and fireproof shaft. See also: permanent shaft support; barring; bunton; wallplate; lagging. Nelson steel ring

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Ring- or horseshoe-shaped support for underground traveling way. Also called arch ring. See also: steel arch steel scrap Miscellaneous pieces of steel, old and new, used in the bath for steel making, esp. in the open-hearth furnace. Mersereau, 2 steel separation door A steel door specially erected for the purpose of being closed only in an emergency, such as a fire or an explosion. Steel is necessary for strength and to avoid destruction by fire. Steel doors may also be used as separation doors in the vicinity of the pit bottom or fan drift. Also called safety door; emergency door. See also: separation door Nelson steel sets Used in main entries of coal mines and in shafts of metal mines in the United States. The sections have I-beams for caps and H-beams for posts or wall plates, the H-section giving equal stiffness in two directions at right angles to each other. Steel sets of various shapes are coming into wide use in deep European coal mines where pressures are so great that timber would not be satisfactory. See also: steel tunnel support Lewis steel sheet piling Piling composed of interlocking rolled steel sections driven vertically into the ground with guide walings in place before excavation starts. Hammond steel shot Chilled cast iron drops. Syn: chilled shot steel support A straight or curved length of steel, usually of H or channel section, used for support purposes in mine roadways, faces, or shafts. A steel support (1) possesses a high degree of permanency or long service; (2) ensures a minimum area of excavation for given dimensions in the clear; and (3) is fireproof. In return airways and shafts, a chromenickel-copper steel is sometimes used to counteract the corrosive air. For high-strength roof bars best results are obtained by the use of heat-treated low-alloy steels of the carbon manganese type. See also: arch girder; steel arch; straight girder support; support; Usspurwies arch; Toussaint-Heintzmann arch. Nelson steel tunnel support 3094

Tunnel-support systems made of steel are roughly of five types: continuous rib; rib and post; rib and wallplate; rib, wallplate, and post; and full circle rib. (1) A continuous rib system is usually made in two pieces for maximum speed of erection, lowest first cost, and lowest erection cost. Sometimes used in three or four pieces to meet special conditions and the following methods of attack: full face, side drift, and multiple drift. (2) A rib and post system is employed with the following methods of attack: full face in tunnels whose roof arch makes an angle with the sidewall; multiple drift and side drift in tunnels of such large size that two-piece continuous ribs cannot be shipped and/or handled; and heading and bench and top heading for support in the drift (with truss panels) for early support to roof. (3) In a rib and wallplate system, the rib is also usually made in two pieces for maximum speed of erection, lowest first cost, and lowest erection cost. It is sometimes used in three or more pieces to meet special conditions and with the following methods of attack: heading and bench, top heading, and full face. This type is esp. applicable to circular and high-sided tunnel sections where only a light roof support is needed. (4) In a rib, wallplate, and post system, these elements of support are used with the following methods of attack: heading and bench and top heading--for quick support to a roof; side drift--in large tunnels with bad rock conditions requiring quick support; and full face--for favorable rock where support is not needed tight to the face, for a tunnel whose roof makes an angle with the sidewall, and where post and rib spacing differ; and (5) A full circle rib--this method is used with the following attack: full face-in tunnels in squeezing, swelling and crushed rock, or any rock that imposes considerable side pressure, also where bottom conditions make it impossible to carry roof loads on foot blocks, and in earth tunnel conditions sometimes encountered in rock tunnels; and heading and bench--under earth tunnel conditions with joints at spring line. The inverted strut is used where mild side pressures are encountered and also to prevent the bottom from heaving. A full circle with ribs closely spaced is heavily lagged for heavy loads associated with squeezing conditions. See also: steel sets Lewis steel wire rope See: wire rope steenstrupine A trigonal mineral, Na14 Ce6 Mn+2 Mn+3 Fe2 (Zr,Th)(Si6 O18 )2 (PO4 )7 .3H2 O . steep See: brasque steep gradient In general, in coal mining, an inclination (of a roadway, working, or coal seam) steeper than 1:4. Nelson 3095

steeply inclined Deposits and coal seams having a dip of from 40 degrees to 60 degrees . Stoces steering brake A brake that slows or stops on one side of a tractor. Nichols, 1 steering clutch A clutch that can disconnect power from one side of a tractor. Nichols, 1 Stefan-Boltzmann Law a. The energy radiated in unit time by a black body is given as E=K(T4 -T04 ) , where T is the absolute temperature of the body, T0 the absolute temperature of the surroundings, and K is a constant. Osborne b. The statement that the radiant flux of a black body is equal to the absolute temperature to the fourth power times the Stefan-Boltzmann constant of (5.6696+ or -0.001)X10-8 W (m)-2 (K)-4 . AGI steigerite A monoclinic mineral, AlVO4 .3H2 O ; weakly radioactive; forms coatings on highly weathered sandstones of the Colorado-Utah carnotite region. stein Stonework used to secure the sides of a shaft. Gordon steinmannite A variety of galena with part of the lead replaced with antimony and arsenic. Standard, 2 stele In coal, primarily the vascular tissues of the axis of a vascular plant. It consists of two parts: the xylem that carries water from the roots, and the phloem that carries the food. Hess stell See: sprag stellate 3096

Said of an aggregate of crystals in a starlike arrangement; e.g., wavellite. stell prop A steel or timber prop fixed firmly between the roof and the floor at the end of a longwall face and from which a coal cutter is hauled by rope when cutting. A stell prop may also be used as part of a belt-tensioning arrangement or a return sheave. Syn: anchor prop See also: conveyor creep stem a. To insert and pack stemming in a shothole. See also: tamp BS, 12 b. The assemblage of drill rods in a borehole connecting a drill bit and core barrel to the drill machine. Long c. The heavy iron rod acting as the connecting link between the bit and the balance of the string of tools on a churn rod in a borehole connecting a drill bit drill. Long d. Frequently used as a syn. for ram or tamp. See: stemming stem bag Fire-resisting paper bag, about 8 in (20.3 cm) long, filled with dry sand for stemming shotholes in coal or hard headings. See: water-ampul stemming stemmer A wooden rod used by shot firers for inserting the explosive cartridges and stemming material in shotholes. The stemmer must be long enough to reach the back of the shothole, and has a diameter 1/8 in (3.2 mm) larger than the cartridges. Metal is not permitted in any part of a stemmer used in British coal mines. Also called tamping rod or stick; beater. See also: tamping; scraper; break detector. Nelson stemming a. The material (limestone chippings or sand and clay) used to fill a shothole, after the explosive charge has been inserted, to prevent the explosion from blowing out along the hole. In tunnels and hard headings, the stemming may be blown in by a hurricane air stemmer. Nelson b. The act of pushing and tamping the material in the hole. See also: water-ampul stemming; tamp. Nelson c. Inert material packed between the explosive charge and the outer end of the shothole, or between adjacent charges in deck charging. BS, 12 d. See: tamping; stem. stemming rod A nonmetallic rod used to push explosive cartridges into position in a shothole and to ram tight the stemming. Syn: stemming stick See also: tamping stick; tamping rod. BS, 12 3097

stemming stick See: stemming rod stench A substance with a distinctive, disagreeable odor put in the air current to warn underground workers of fire or other emergency; ethyl mercaptan is commonly used. Hess stench capsule A fire-warning device designed to be bolted to a flat surface that may rise to a dangerous temperature. It consists of a cavity filled with 20 cm 3 of ethyl or butyl mercaptan alone or with other stench agents and is sealed with a fusible plug in a brass container with a hexagonal head, arranged to liberate the stench agent at any temperature chosen. Tests in pits have shown that a strong smell could be detected 1.7 miles (2.7 km) from the discharge point 25 to 30 min after the device operated. Sinclair, 1 stenonite A monoclinic mineral, (Sr,Ba,Na)2 Al(CO3 )F5 . stent a. The amount of work expected from a coal miner in a day or week. See also: stint b. See: pitch c. Corn. Tourmaline and quarz veins in kaolinized granite. d. U.K. Rubble; waste. e. U.K. Extent or limit, as of a pitch or bargain. stenting N. of Eng. See: stenton stenton A connecting roadway between two adjacent roadways that may be used for ventilation purposes. Also called air slit; crosscut; cross hole; thirling; througher; spout. Syn: crosscut breakthrough; pillar-and-stall. BS, 8 step a. Fault; a small fault; a small fault in a stepped series of faults. Mason b. A small offset on a piece of core or in a drill hole resulting from a sudden sidewise deviation of the bit as it enters a hard, tilted stratum or rock underlying a softer rock. CF: kick c. One of several terracelike or stairstep concentric configurations on the crown of a diamond bit. 3098

See also: step-face bit d. A treatment of one part of a sample in a sample divider (thus a pass consists of one or more steps). BS, 3 e. The action of setting a lock gate into a vertical position. Hammond step cut a. A mode of cutting gems in steplike facets. Standard, 2 b. A form of cutting employed for stones not deeply colored when they are not cut as brilliants; a simple typical form is that of a stepped pyramid with the apex sliced off. Also called trap cut. Hess c. A style of cutting, widely used on colored gemstones, in which long, narrow, four-sided facets form in a series or row parallel to the girdle and decrease in length as they recede above and below the girdle, giving the appearance of steps. The number of rows, or steps, may vary, although it is usually three on both the crown and pavilion. Different shapes of step cuts are described by their outline; e.g., rectangular or square step cut. Syn: trap cut step-face bit A thin-nosed bit with diamonds set in several concentric terracelike rows that form the outside wall. Long step fault a. One of a set of parallel, closely spaced faults over which the total displacement is distributed. CF: fault zone distributive fault. AGI b. One of a series of low-angle thrust faults in which the fault planes step both down and laterally in the stratigraphic section to lower glide planes. Step faulting is due to variation in the competence of the beds in the stratigraphic section. AGI c. A series of parallel faults that, all inclined in the same direction, gives rise to a gigantic staircase; hence these are called step faults. Each step is a fault block and its top may be horizontal or tilted. AGI stephanite An orthorhombic mineral, Ag5 SbS4 ; soft; metallic; sp gr, 6.2 to 6.3; in veins; a source of silver. Syn: brittle silver ore; black silver; goldschmidtine. Stephenson lamp An early type of coal miners' lamp. It had a glass chimney surrounded by a wire gauze about 2 in (5.1 cm) in diameter. The glass chimney was covered by a perforated copper cap, and the air was fed to the flame from below through small holes and wire gauze in a lateral extension of the oil vessel. The lamp was unsafe; it passed flame when the velocity of the air current exceeded about 8 ft/s (2.4 m/s). See also: safety lamp Nelson steppe 3099

An extensive, treeless grassland area in the semiarid mid-latitudes of southeastern Europe and Asia. It is generally considered drier than the prairie which develops in the subhumid midlatitudes of the United States. AGI stepped foundation See: benched foundation stepped longwall A system of longwall stalls in which the faces are carried forward in a steplike formation, one stall about 5 yd (4.6 m) in advance of the next stall. It is claimed to have advantages when the roof is friable. See also: top holes stepped stope The term implies that mining at one face is stepped aside from that below so as not to hinder the work at it. Syn: advance stope stepping ahead Term used in dredging operations when the digging spud is dropped, the other spud is raised, and the dredge is ready to begin a new cut. Lewis step reef See: step vein step socket A special form of socket for use on locked-wire rope. Zern step up To increase the voltage of (a current) by means of a transformer. Webster 3rd step vein A vein alternately cutting through the strata of country rock and conforming with them. Syn: step reef stercorite A triclinic mineral, H(NH4 )Na(PO4 ).4H2 O . Syn: microcosmic salt 3100

stereocomparator A stereoscope for accurately measuring the three space coordinates of the image of a point on an aerial photography; it is used in making topographic measurements by the comparison of stereoscopic photographs. AGI stereogram a. A graphic diagram on a plane surface, giving a three-dimensional representation, such as projecting a set of angular relations; e.g., a block diagram of geologic structure, or a stereographic projection of a crystal. AGI b. A stereoscopic pair of photographs correctly oriented and mounted for viewing with a stereoscope. Syn: stereographic projection; stereograph. AGI stereograph See: stereogram stereographic projection a. A map projection in which meridians and parallels are projected onto a tangent plane, with the point of projection on the surface of the sphere diametrically opposite to the point of tangency of the projecting plane. Any point of tangency may be selected (at a pole, on the equator, or a point in between). AGI b. A similar projection used in optical mineralogy and structural geology, made on an equatorial plane (passing through the center of the sphere) with the point of projection at the south pole. Syn: stereogram AGI stereometric map A relief map made by the application of the stereoscopic principle to aerial or terrestrial photographs. Syn: stereotopographic map stereoscopic principle The formation of a single, three-dimensional image by simultaneous vision with both eyes of two photographic images of the same terrain taken from different camera stations. AGI stereoscopic vision Simultaneous vision with both eyes in which the mental impression of depth and distance is obtained, usually by means of two different perspectives of an object (such as two photographs of the same area taken from different camera stations); the viewing of an object in three dimensions. Syn: stereoscopy; stereovision. AGI 3101

stereoscopy See: stereoscopic vision stereosphere a. That part of the Earth's crust that lies above the level of compensation, or the top of the asthenosphere. See also: asthenosphere AGI b. The relatively strong outer shell of the Earth. AGI c. A term that was originally proposed for the innermost shell of the Earth's mantle, but is also used as equivalent to the lithosphere. AGI stereotopographic map See: stereometric map stereovision See: stereoscopic vision sterilized coal That part of a coal seam that, for various reasons, is not mined. BS, 7 sterling silver A silver alloy containing at least 92.5% silver, the remainder being unspecified but usually copper. ASM, 1 sternbergite An orthorhombic mineral, AgFe2 S3 ; cubanite group; forms tabular crystals or soft flexible laminae. Syn: flexible silver ore sterny Scot. Rough; coarse-grained or crystalline, for example, sterny limestone. sterrettite See: kolbeckite stetefeldite A somewhat uncertain compound containing silver, copper, iron, antimony, sulfur, and water [Ag2 Sb2 (O,OH)7 ] (?). 3102

Stetefeldt furnace A furnace for the chloridizing and roasting of silver ores, and also for roasting fine copper ores low in sulfur. Provision is made for an auxiliary fireplace. Fay stevensite A monoclinic mineral, Ca/2)0.3 Mg3 Si4 O10 (OH)2 ; smectite group; with no tetrahedral substitution of Al for Si, its layer charge arises from octahedral vacancies. Syn: aphrodite stewartite a. A triclinic mineral, MnFe2 (PO4 )2 (OH)2 .8H2 O ; dimorphous with laueite; forms minute crystals and tufts of fibers in pegmatites. b. A steel-gray, ash-rich, fibrous variety of bort containing iron, having magnetic properties, in the diamond mines of Kimberley, South Africa. stey Scot. Steep; highly inclined. stibianite See: stibiconite stibiconite a. An isometric mineral, Sb3 O6 (OH) ; pale yellow or chalky white; in antimony ore deposits as an alteration of stibnite. Syn: stibianite; stiblite. b. The mineral group blindheimite, lewisite, partzite, romeite, stetefeldtite, and stibiconite. stibiocolumbite An orthorhombic mineral, SbNbO4 ; forms a series with stibiotantalite. stibiopalladinite A hexagonal mineral, Pd5 Sb2 ; sp gr, 9.5; occurs with platinum ores; a source of platinum and palladium. Syn: allopalladium stibiotantalite An orthorhombic mineral, SbTaO4 ; forms a series with stibiocolumbite. stibium 3103

The ancient name for antimony and stibnite and now used in pharmacy for the metal. See: stibnite stiblite See: stibiconite stibnite An orthorhombic mineral, Sb2 S3 ; dimorphous with metastibnite; soft; metallic; may contain gold and silver; occurs in massive forms and in vertically striated prisms having perfect cleavage, in low-temperature veins and around hot springs; the chief source of antimony. Syn: antimonite; antimony glance; gray antimony; stibium. See also: stibnium stibnium An ancient name for "stibnite" used (as in Egypt) as a cosmetic for painting the eyes. See also: stibnite stichtite A trigonal mineral, Mg6 Cr2 (CO3 )(OH)16 .4H2 O ; hydrotalcite group; dimorphous with barbertonite; lilac colored; in Dundas, Tasmania, Australia; Transvaal, South Africa; Cunningsburgh, Shetland Islands; and Quebec, Canada. stick A cartridge of explosive. BCI sticking a. A small vein (a scrin) not wide enough for shoulder room, Derbyshire, U.K. Arkell b. The selvage of mineralized country rock at the side of a vein. Arkell c. A rib or ore in a vein, or a small rake vein crossing the main vein, Derbyshire, U.K. Arkell d. U.K. A thin vein of ore or thin seam of clay in an ore vein. sticking scrins Eng. Small veins that do not afford shoulder room. stick loading A technique used in trench blasting, etc., in which a lower concentration of charge is obtained by placing wooden pegs between every cartridge in the hole thus halving the concentration. Langefors 3104

stickup See: standoff sticky A term applied when drilling rock or a formation so soft that the drill bit tends to penetrate too rapidly and the circulation fluid is unable to clear the cuttings away fast enough to prevent their adhering to and compacting on the surfaces of the bit and other downhole drilling equipment and/or the borehole sidewalls. CF: balling formation; gummy. Long sticky limit The lowest water content at which a soil will stick to a metal blade drawn across the surface of the soil mass. ASCE stiff clay Clay of low plasticity. stiffener A steel angle or bar riveted or welded across the web of a built-up girder to stiffen it. CTD stiff-fissured clay A clay that is firm when dry at depth but is intersected by cracks through which water will seep easily. Clay deposits of this type are liable to slips on hillside slopes. Syn: slickensided clay stiff mud A plastic mix of clay of very stiff consistency, as extruded from an auger machine. stiffness The ability of a metal or shape to resist elastic deflection. For identical shapes, the stiffness is proportional to the modulus of elasticity. ASM, 1 stifle Scot. Noxious gas resulting from an underground fire. 3105

stilbite a. A monoclinic and triclinic mineral, Na2 Ca4 [Al10 Si26 O72 ].34H2 O ; zeolite group, with K replacing Na; forms sheaflike crystal aggregates and radiated masses in cavities in igneous rocks, as an alteration of plagioclase, or in hydrothermal veins. b. Ger. See: heulandite still a. An apparatus in which a substance is changed by heat into vapor, with or without chemical decomposition. The vapor is then liquefied in a condenser and collected in another part of the apparatus. Standard, 2 b. See: amalgam retort still coke The residue left in the still on distilling crude shale oil to dryness. Fay stilling well A chamber connected to a main body of water by a small inlet; such an arrangement is suitable for a recording gage. Hammond Stillson wrench The pipe wrench of common use, named for its inventor. Crispin stillwellite A trigonal mineral, (Ce,La,Ca)BSiO5 . stilpnomelane A monoclinic and triclinic mineral, K(Mg,Fe)8 (Si,Al)12 (O,OH)27 (?) ; black to greenblack; in micalike plates, fibrous forms, and velvety bronze-colored incrustations. Syn: chalcodite stilt A device to allow roadway steel arches a measure of yield under roof pressure to prevent buckling. The stilt may take the form of wooden extensions strapped to the legs of the arch, wire bags filled with dirt, a mechanical frictional appliance, or a hydraulic stilt. See also: yielding support stinger 3106

a. A steel cylinder projecting beyond the face of a cutting bit that serves as a pilot or guide. See also: pilot b. The pneumatically actuated piston attached to a pointed rod that acts as a feed mechanism on a stoper drill. Long stinger ream To ream a borehole using a reaming bit equipped with a pilot or stinger. Long sting-out Hot air and flame exhausted through openings in furnaces or tanks due to positive internal pressure. ASTM stinkdamp A mining term for hydrogen sulfide. The gas has an unpleasant smell, resembling that of rotten eggs, hence the name. The presence of this gas may indicate a gob fire in its early stages. Produced by the distintegration of iron pyrites. See also: damp stinker a. A British miner's term for inferior coal that stinks when burned. Tomkeieff b. A Welsh term for dolomite. Arkell stinkquartz A variety of quartz that emits a fetid odor when struck. Fay stinkstein See: stinkstone stinkstone a. A stone that emits an odor on being struck or rubbed; specif. a bituminous limestone (or brown dolomite) that gives off a fetid smell (owing to decomposition of organic matter) when rubbed or broken. It may emit a sweet-and-sour smell if the carbonate rock is rich in organic-phosphatic material. See also: anthraconite; bituminous limestone. Syn: stinkstein b. Boulders of phosphate rock from Tennessee. stint A fixed work target on the coalface that every collier is expected to do in one shift or a single week. In longwall conveyor work, it is the length, area, or volume of face that the miner regularly clears or loads out. Also called stent; cut. Syn: cut 3107

stip See: hitch stirian An early name for nickel-bearing marcasite. stitch To fasten a timber by toenailing. stitched canvas conveyor belt A construction of conveyor belt made up of plies of cotton fabric stitched together. Stitched canvas belts may be untreated, impregnated, or coated. See also: belt stochastic Containing a random variable; word used to describe a system (e.g., sampling method) that has in it an element of randomness. Pryor, 3 stock a. A rarely used term for a chimneylike orebody. Syn: pipe b. An irregular, metalliferous mass in a rock formation, such as a stock of lead ore in limestone. CF: boss stock craneman Person who lifts and moves stock, such as limestone, scrap iron, or pig iron, for the open-hearth furnace. DOT stockhouse larryman Person who drives an electric car to haul ore and limestone from the stockpiles to the blast furnace. DOT stocking conveyor A belt conveyor in a blending system that receives bulk materials for delivery to the stacker conveyor. stockpile

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a. An accumulation of ore or mineral built up when demand slackens or when the treatment plant or beneficiation equipment is incomplete or temporarily unequal to handling the mine output; any heap of material formed to create a reserve for loading or other purposes. Nelson b. The ore accumulated at the surface when shipping is suspended. Standard, 2 c. Material dug and piled for future use. Nichols, 2 stockwork A mineral deposit consisting of a three-dimensional network of planar to irregular veinlets closely enough spaced that the whole mass can be mined. CF: reticulate stockyard A space reserved on the surface near the materials shaft for the temporary storage of steel, timber, and other bulky items of supplies for mine use. The yard is surfaced and a mine car is used throughout. Nelson stoichiometric With reference to a compound or a phase, pertaining to the exact proportions of its constituents specified by its chemical formula. It is generally implied that a stoichiometric phase does not deviate measurably from its ideal composition. AGI stoke Unit of kinematic viscosity. The cgs unit of kinematic viscosity being that of a fluid that has a viscosity of 1 P (100 mPa.s) and a density of 1 g/cm3 . Webster 3rd stokehole A hole, as in a reverberatory furnace, for introducing a rabble or other tool for stirring. Standard, 2 stoker A mechanical appliance for feeding coal, coke, or other fuel into a boiler or furnace. In hand stoking, the person who shovels the fuel into the furnace is known as the stoker. See also: underfeed stoker; vibrating grate. Nelson stoker coal a. A screen size of coal specif. for use in automatic firing equipment. BCI b. This coal can be of any rank and the stoker is usually designed to fit the coal available. Factors of importance in the selection of coal for stoker use are size limits; size consist; uniformity 3109

of shipments; coking properties; ash-fusion characteristics; ash, sulfur, and volatilematter percentages. Mitchell stokesite An orthorhombic mineral, CaSnSi3 O9 .2H2 O ; forms acute pyramids; at Roscommon Cliff, St. Just, Cornwall, U.K. Stokes' law a. A formula expressing the rates of settling of spherical particles in a fluid. AGI b. Gives the rate of fall of a small sphere in a viscous fluid. When a small sphere falls under the action of gravity through a viscous medium it ultimately acquires a constant velocity, V: V = 2ga2 (d1 -d2 )/9eta where g is gravitational acceleration, a is the radius of the sphere, d1 and d2 are the densities of the sphere and of the medium, respectively, and eta is the coefficient of viscosity. V will be in centimeters per second if g is in centimeters per second per second; a will be in centimeters; d1 and d2 will be in grams per cubic centimeter; and eta will be in dynes second per square centimeter, or poises. Handbook of Chemistry and Physics, 2 c. The wavelength of light emitted by a fluorescent material is longer than that of the radiation used to excite the fluorescence. In modern language, the emitted photons carry off less energy than is brought in by the exciting photons; the details accord with the energy conservation principle. See also: elutriator; sedimentation test; terminal velocity. Handbook of Chemistry and Physics, 2 d. At low velocities, the frictional force on a spherical body moving through a fluid at constant velocity is equal to 6pi times the product of the velocity, the fluid viscosity, and the radius of the sphere. The wavelength of luminescence excited by radiation is always greater than that of the exciting radiation. McGraw-Hill, 1 Stokes stretcher The simplest type of stretcher used for underground first aid. This basket-type stretcher acts as a splint for the whole body, and is constructed of tubular steel and strong wire mesh. Used for lifting or lowering injured persons in difficult places. This type of stretcher is used in metal mines or in coal mines where the coalbed has a steep pitch. See also: stretcher stoking See: continuous sintering stoltzite A tetragonal mineral, 4[PbWO4 ] ; dimorphous with raspite; crystallizes in bipyramids; sp gr, 7.9 to 8.3; in oxidized zones of tungsten deposits. 3110

stomp A short wooden plug fixed in the roof, to which lines are hung, or to serve as a bench mark for surveys. Fay stone a. A mineral or group of consolidated minerals either in mass or in a fragment of pebble or larger size. AGI b. A stony meteorite. c. A cut and polished gem or other precious mineral (but not a synthetic compound used in ornamentation). d. Crushed or naturally angular particles of rock that will pass a 3-in (7.6-cm) sieve and be retained on a No. 4 U.S. Standard sieve. ASCE stone band See: dirt band stone bind Eng. Interbedded layers of sandstone and shale, or for a rock (such as siltstone) intermediate between a sandstone and a mudstone. AGI stone butter a. A variety of halotrichite. Syn: rock butter b. A variety of alum. c. A variety of clay. stone clunch Eng. Very hard underclay (clunch) with interbeds of sand. AGI stone coal a. Wales. Anthracite, in lumps; also certain other very hard varieties of coal. Fay b. Mineral coal, as distinguished from charcoal; esp., in England, hard or anthracite coal. Standard, 2 c. Sometimes applied to anthracite on account of its hardness. See also: anthracite d. Early term for anthracite. Korson stone concentration See: diamond concentration stone content See: diamond content 3111

stone count See: diamond count stone crane operator a. In the quarry industry, a person who lifts blocks of stone and boxes of broken stone with a guy derrick in a quarry. Also called stone hoist operator. DOT b. In the stonework industry, one who lifts and moves blocks of stone with an electric bridge crane in a stone mill. DOT stonecutter a. Person whose occupation is cutting stone; a stone mason. Standard, 2 b. A gem cutter. Standard, 2 c. A machine for facing stone. Standard, 2 stone drift A drift excavated in rock, such as from the surface down to a coal seam. See also: hard heading; rock drivage; slant. Nelson stone dust a. In coal mines any inert dust spread on roadways as a defense against the danger of coal dust explosions. The stone dust used is of a type that does not cake in mine air. Ground limestone is satisfactory in most conditions. About 5% less limestone is required than shale, and gypsum has about two to three times the efficiency of shale. Gypsum appears to owe its high efficiency to its hydrate water. Inert dusts are effective because they absorb heat that the coal dust would otherwise receive from the flame. See also: dust consolidation b. Shale dust. Mason c. Loosely applied to any incombustile dust used to render coal dust incombustible. Mason stone-dust barrier A device erected at strategic points in mine roadways for the purpose of arresting explosions. Consists essentially of trays loaded with stone dust, which are upset or overturned by the pressure wave in front of an explosion ahead of the flame, producing a dense curtain or cloud of inert dust to blanket the flame and stop further propagation of the explosion. See also: colliery explosion; flame inhibitor. Sinclair, 1 stone duster The person in charge of stone dusting in coal mines. Nelson stone dusting 3112

The systematic distribution of stone dust along mine roadways to cover the coal dust and reduce its flammability. Although stone dusting may not always stop an explosion, it is less violent with stone dusting than without. Safety regulations in many countries require that stone dust be applied either mixed with the coal dust along mine roadways or as stone dust barriers, to reduce the liability of coal-dust explosions. Nelson; Roberts, 1 stone exposure See: diamond exposure stone fields See: block field stone flax An early name for asbestos. stone gobber In bituminous coal mining, person who removes stone and other refuse from coal mine floors and dumps refuse into mine cars for disposal. DOT stone hammer A hammer for breaking or dressing stone. Standard, 2 stonehead a. U.K. A heading driven in stone or bind. b. The solid rock first met in sinking a shaft. c. See: bedrock stone intrusion Irregular masses of sandstone occurring within a coal seam or penetrating the seam from top to bottom, sometimes much distorted, but always connected with a similar sandstone in the roof or higher strata. Also called stone eye. See also: drop stone land An area that is economically valuable for some variety of stone, such as granite or sandstone, that can be quarried. CF: mineral land AGI stoneman 3113

a. A miner employed on stonework. See also: ripper b. A worker who drills shotholes in rock in readiness for firing by the shotfirer. Hammond stone mill a. A stone crusher. Standard, 2 b. A machine for dressing and finishing marble, slate, etc.; a stone dresser. Standard, 2 stone mine a. Scot. An ironstone mine or working. b. Scot. A mine driven in barren strata. stone ocher Ocher found in hard globular masses. Webster 3rd stone of ore A piece of ore. stone per carat The number of near-equal-size diamonds the weight of which is 1 carat, hence a relative measure of the size of diamonds. Syn: diamonds per carat stone pit A quarry where stones are dug. Webster 2nd stone planer In the concrete products and stonework industry, person who shapes, smooths, squares, and removes excess material from the surfaces of blocks or slabs of building or ornamental stone (limestone, slate, sandstone, marble, and such concrete work as imitation marble) on a planer. Also called planer hand; planer man; planer operator; planing machine operator. DOT stone polisher In the stonework industry, person who polishes to a high luster by hand methods those curbed, irregular, and straight surfaces of blocks and slabs of marble and granite that cannot be polished by machine. May be designated according to kind of stone, such as granite polisher or marble polisher. Also called stone finisher. DOT stone pressure 3114

See: diamond pressure stones a. Detached particles of rock usually smaller than 10 in (25 cm) in diameter. Stones are classed as gravel on bottom sediment charts. Hunt b. In mica, small embedded crystals or holes resulting from stones. Also called stone holes. Skow stone saw A stone-cutting apparatus having no teeth, being a simple iron band fed with sand and water, cutting by attrition. Standard, 2 stone sawyer Person who cuts stone. stone sill Cumb. Sandy fireclay. CF: sill stone spavin York. Usually a stone bind or sandstone with rootlets. Arkell stone tubbing Watertight stone walling of a shaft cemented at the back. stone wall See: hogback stoneware clay A clay suitable for manufacture of stoneware (ceramic ware fired to a hard, dense condition and with an absorption of less than 5%); used for items such as crocks, jugs, and jars. It possesses good plasticity, fusible minerals, and a long firing range. AGI stone weight See: diamond content stonework 3115

a. All underground work involving the excavation, loading, or handling of rock or dirt, such as ripping, dinting, tunneling, packing, etc. In thin coal seams, stonework is a major cost item. See also: dead work Nelson b. The process of working in stone; the shaping, preparation, or setting of stone. Webster 3rd stone yellow See: yellow ocher stony clunch Eng. Compressed clays with sandstone layers interspersed, Midlands. Arkell stook The last stump or corner block of coal left when extracting pillars by means of lifts, in pillar methods of working. Nelson stool a. The point where a miner stops digging downward to work outward. Hess b. The assembly carrying the return rollers and brackets for connecting standard sections together in belt conveyors. Nelson stooled Eng. Applied to a vein cut vertically for some distance. stool end A supporting pillar mine. Webster 3rd stoop-and-room See: bord-and-pillar stooper A miner in pillar methods of working employed in pillar robbing; a practice now obsolete. Nelson stoopway A passageway, the height of which requires a person to stoop or crouch in traversing it. AGI 3116

stop a. Any cleat or beam to check the descent of a cage, car, pump, pump rods, etc. b. In mining, a variation of stope. stopblocks A simple arrangement of two stout timbers, sliding on pivots, one of which can be placed across the track rail and held in position by the other block. They are often used on haulage landings to prevent trams running down the incline uncontrolled. Syn: nubber stope a. An excavation from which ore has been removed in a series of steps. A variation of step. Usually applied to highly inclined or vertical veins. Frequently used incorrectly as a syn. for room, which is a wide-working place in a flat mine. Standard, 2 b. To excavate ore in a vein by driving horizontally upon it a series of workings, one immediately over the other, or vice versa. Each horizontal working is called a stope because when a number of them are in progress, each working face under attack assumes the shape of a flight of stairs. When the first stope is begun at a lower corner of the body of ore to be removed, and, after it has advanced a convenient distance, the next is commenced above it. This is called overhand stoping. When the first stope begins at an upper corner, and the succeeding ones are below it, it is called underhand stoping. The term stoping is loosely applied to any subterranean extraction of ore except that which is incidentally performed in sinking shafts, driving levels, etc., for the purpose of opening the mine. c. Commonly applied to the extraction of ore, but does not include the ore removed in sinking shafts and in driving levels, drifts, and other development openings. Lewis d. The working above and below a level where the mass of the orebody is broken. A stope is the very antithesis of a shaft, tunnel, drift, winze, or other similar excavation in a mine. Ricketts e. Any excavation in a mine, other than development workings, made for the purpose of extracting ore. The outlines of the orebody determine the outlines of the stope. The term is also applied to breaking ground by drilling and blasting or other methods. See also: caving f. A body of mineral left by running drifts about it. Standard, 2 stope board A timber staging on the floor of a stope for setting a rock drill. The stage is tilted to enable the bottom holes being drilled in the same inclined direction. Nelson stope development The driving of subsidiary openings designed to prepare blocks of ore for actual extraction by stoping. stope driller 3117

In metal mining, one who operates compressed air, percussion-type rock drill in a stope (an underground opening from which ore is extracted in a series of steps). Also called stoper. DOT stope fillings Broken mullock or rock or the broken low-grade portion of a lode or vein used to fill stopes on abandonment. Nelson stope hoist A small portable compressed-air hoist for operating a scraper-loader or for pulling heavy timbers into position, often used in narrow stopes. Nelson stope miner See: miner stop end The shuttering erected at the end of a length of concrete construction and shaped to provide a suitable joint for the next length. Hammond stope pillar A column of ore left to support the stope. Pryor, 3 stoper a. A stoping drill. b. A light percussive drill incorporating a pneumatic cylinder to provide support and thrust while drilling steeply upward. BS, 12 c. See: stope driller stoperperson See: roof bolter stope sampling The sampling of exposure in the stopes, or of material coming from the stopes. This type of sampling permits a closer control of the grade of ore being won and is conducted largely at the working place or stope. Truscott stope scraper

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In metal mining, one who shovels or rakes ore into mine cars in a stope (an underground opening in a vein from which ore is extracted in a series of steps). Syn: hand scraper stope washings In gold mines, auriferous slimes washed down from the floor (footwall) of the stope and sent to the mill. Pryor, 3 stoping a. The act of excavating rock, either above or below a level, in a series of steps. In its broadest sense rock stoping means the act of excavating rock by means of a series of horizontal, vertical, or inclined workings in veins or large, irregular bodies of ore, or by rooms in flat deposits. It covers the breaking and removal of the rock from underground openings, except those driven for exploration and development. The removal of ore from drifts, crosscuts, shafts, winzes, and raises, which are excavated to explore and develop an ore deposit, is incidental to the main purpose for which stopes are driven and is not a stoping operation. Exploratory and development openings are driven to prepare a mine for extraction of the ore by stoping. See also: stope b. In civil engineering, an enlargement. Fraenkel c. The loosening and removal of ore in a mine either by working upward (overhead or overhand) or downward (underhand). AGI stoping-and-filling See: overhand stoping stoping drill A small air or electric drill, usually mounted on an extensible column, for working stopes, raises, and narrow workings. stoping ground Part of an orebody opened by drifts and raises, and ready for breaking down. stoping in horizontal layers See: overhand stoping stoping methods The classification of stoping methods adopted by the U.S. Bureau of Mines, devised largely on the basis of rock stability, is as follows: (1) stopes naturally supported--this includes open stoping with open stopes in small orebodies, and sublevel stoping; and open stopes with pillar supports that includes casual pillars and room (or stope) and 3119

pillar (regular arrangement); (2) stopes artifically supported--this includes shrinkage stoping, with pillars, without pillars, and with subsequent waste filling; cut-and-fill stoping; stulled stopes in narrow veins; and square-set stoping; (3) cave stopes--this includes caving (ore broken by induced caving), block caving, including caving to main levels and caving to chutes or branched raises; sublevel caving and top slicing (mining under a mat that, together with caved capping, follows the mining downward in successive stages); and (4) combinations of supported and caved stopes (as shrinkage stoping with pillar caving, cut-and-fill stoping with top slicing of pillars, etc.) stoping underhand Mining a stope downward in such a series that presents the appearance of a flight of steps. stoping width a. Width of lode broken during mining, including any barren rock. Pryor, 3 b. Used in underground sampling and is estimated from direct measurement behind the stope face and reduced to allow for any waste stowed. With wide tabular deposits, there is little difference between the stoping width and the clean width. Nelson stopoff To close off part of a mine by means of a brattice, wall, stopping, etc. stopper hole In a puddling furnace, the hole through which the rabble is introduced. Webster 2nd stopper maker One who forms and finishes fire clay stoppers for open hearth ladles, using a stopper press and a finishing machine. DOT stopping a. A brattice, or more commonly, a masonry or brick wall built across old headings, chutes, airways, etc., to confine the ventilating current to certain passages, and also to lock up the gas in old workings, and in some cases to smother a mine fire. b. A permanent wall built to close off unused crosscuts to prevent the air from short circuiting. Lewis c. A dam or seal to isolate old workings containing water or injurious gases. See also: dam; inrush of water. Syn: ventilation stopping Nelson stopping builder 3120

In bituminous coal mining, one who builds walls of concrete, stone, or brick and mortar, to close off old passageways or haulageways underground, to maintain ventilation in new workings. DOT storage battery locomotive An underground locomotive powered by storage batteries. Hammond Storrow whirling hygrometer A hygrometer in which the two thermometers are mounted side by side on a brass frame and fitted with a loose handle so that it can be whirled in the atmosphere to be tested. The instrument is whirled at some 200 rpm for about 1 min and the readings on the wetand dry-bulb thermometers recorded; used in conjunction with Glaisher's or Marvin's hygrometrical tables. It gives more consistent and accurate results than the ordinary instrument. See also: whirling hygrometer stottite a. A tetragonal mineral, FeGe(OH)6 ; greasy; at Tsumeb, Namibia. b. The mineral group jeanbandyite, mopungite, stottite, and tetrawickmanite. stove a. A large steel furnace or oven connected with the blast furnace to preheat the blast before it is introduced into the furnace proper. Mersereau, 2 b. A kiln, as for firing pottery or drying minerals. Webster 2nd stove coal a. In anthracite only; two sizes of stove coal are made, large and small. Large stove, known as No. 3, passes through a 2-1/4- to 2-in (5.7- to 5-cm) mesh and over a 1-7/8- to 1-1/2-in (4.8- to 3.8-cm) mesh; small stove, known as No. 4, passes through a 1-7/8- to 1-3/8-in (4.8- to 3.5-cm) mesh and over a 1-1/8- to 1-in (2.9- to 2.5-cm) mesh. Only one size of stove coal is now usually made. It passes through a 2-in (5-cm) square mesh and over a 1-3/8-in (3.5-cm) square mesh. Zern b. See: anthracite coal sizes stoved salt Stoved open-pan salt. Kaufmann stovepipe Riveted-seam or spiral-welded-seam, thin-wall pipe used as a conductor, standpipe, or casing in a borehole. Long 3121

stovepipe casing See: stovepipe stow a. To pack away rubbish into goaves or old workings. b. To gob; to fill the waste; to put debris into the waste. Mason stowage Scot. In longwall mining the space from which the mineral has been extracted and which has been filled with waste. stowce Derb. A wooden landmark, placed to indicate possession of mining ground. Also spelled stowse. stowing a. A method of mining in which all the material of the vein is removed and the waste is packed into the space left by the working. b. The debris of a vein thrown back of a miner and which supports the roof or hanging wall of the excavation. Zern c. See: solid packing stowing method Any of several methods of working coal or ore deposits in which systematic stowing of the worked out areas is part of the system. See also: coal mining methods; solid stowing; strip packing. Nelson straddle A vertical mine timber, esp. one supporting a set in a shaft. straddle spread See: split spread strahlite From the German "strahlstein." (radiating stone), the original name for actinolite (Greek "aktis" radiating). See also: actinolite 3122

straight Common term for straight brick, as a 9-in (23-cm) straight. straightaway In stripping, a pit that follows a straight line when projected on a horizontal plane. Woodruff straight chopping bit See: chopping bit straight-cut gang frame In quarrying, a saw gang that slides back and forth on a bed, as contrasted with the ordinary saw gang that swings back and forth when suspended from above. straight dynamites Dynamites composed of nitroglycerin, a combustible such as wood meal, sodium nitrate, and an antacid, such as calcium or magnesium carbonate, and are made in 15% to 60% strength, the percentage representing the proportion of nitroglycerin in the dynamites. They are powerful, quick acting, and fairly water resistant, but on detonation produce poisonous gases, esp. in the higher grades. Their relatively high cost, sensitivity to shock and friction, and high flammability, together with the dangerous fumes developed, make them less suitable for general use than more recently developed modifications. Lewis; Carson, 1 straightedge leveling A system of leveling using a straightedge and a spirit level. BS, 7 straight girder support An H-section girder used as a roadway or face beam support. The girder for spanning roadways is commonly 6 in (15.2 cm) deep and 5 in (12.7 cm) in width of flange. It is supported by wood or steel props or by brick or concrete sidewalls, the roof being made secure by timber or sheet lagging. Channel section girders are also used in special cases. See also: steel support straight point Aust. That straight portion of the inner main rail between the rails of a turnout. 3123

straight-side core bit See: straight-wall bit straight stall A lateral excavation into a thick seam of coal. Also called straight coal. Standard, 2; Fay straight-type wedge A plain deflecting wedge, not equipped with a rose or stabilizing ring. Long straight-wall bit An annular-shaped (core) bit the inner walls of which are parallel with the outer walls and not tapered to receive a core lifter. Syn: straight-side core bit straight-wall core shell a. A reaming shell the outside walls of which are straight and not set with diamonds or hard-metal reaming points. Long b. Sometimes used as a syn. for blank reaming shell. Long straight work a. Narrow headings in coal. CTD b. A method of working coal by driving parallel headings and then removing the coal between them. CTD strain a. Change in the shape or volume of a body as a result of stress; a change in relative configuration of the particles of a substance. Syn: deformation b. Deformation resulting from applied force; within elastic limits strain is proportional to stress. CF: stress c. A measure of the change in the size or shape of a body, referred to its original size or shape. Linear strain is the change per unit length of a linear dimension. True strain (natural strain) is the natural logarithm of the ratio of the length at the moment of observation to the original gage length. Conventional strain is the linear strain referred to the original gage length. Shearing strain (shear strain) is the change in angle (expressed in radians) between two lines originally at right angles. When the term strain is used alone, it usually refers to the linear strain in the direction of the applied stress. See also: true strain ASM, 1 d. There are, generally speaking, two kinds of strains: normal and shear. Normal strains are those that may result in the relative displacement of two particles along the line joining those particles, whereas in shear strains, the particles are displaced at a right angle to the line joining them. All possible deformations may be represented as a combination of these two types of strain. Issacson 3124

strain bar An instrument well suited for measuring the strain on a rock face. It consists essentially of an invar steel bar with a fixed point at one end and a movable point attached to a rider at the other end. The rider may be moved along the bar between two stops, and the extent of movement is indicated by a dial gage attached to the bar. Issacson strain break Fractures occurring in rock quarries where the rock is under compressive stress. This stress is relieved locally in the process of quarrying, resulting in the rending or fracturing of the rock mass. strain burst Rock burst in which there is spitting, flaking, and sudden fracturing at the face, indicating increased pressure there. Higham strain cleavage See: slip cleavage strain ellipsoid In elastic theory, a sphere under homogeneous strain is transformed into an ellipsoid with this property; the ratio of the length of a line, which has a given direction in the strained state, to the length of the corresponding line in the unstrained state, is proportional to the central radius vector of the surface drawn in the given direction. The ellipsoid whose half axes are the principal strains. CF: reciprocal strain ellipsoid strain gage a. A general term for a device with which mechanical strain can be measured, commonly by an electrical signal, e.g., a wire strain gage. AGI b. An electrical, mechanical, or optical device for measuring movement of rock, cumulative loading of support props, opening cracks, etc. Pryor, 3 c. An electromechanical device that transforms small displacements to changes in resistance that are proportional to the displacement. Strain gages are used in ocean bottom pressure measuring equipment. Hunt strain relief method A technique for the determination of absolute (total) strain and stress within rock in situ. In this method, a smooth hole is bored in the rock and a gage is inserted to measure diametral deformation. The hole is then overcored with a large coring bit so that the cylinder of rock containing the deformation measuring gage is free to expand. The 3125

change in the diameter of the hole when the rock cylinder is free to expand is a function of the original stress in the rock and its elastic modulus. Woodruff strain restoration method A technique for the determination of absolute (total) strain and stress within rock in situ. This method involves (1) installation of strain gages on the rock surface; (2) cutting of a slot in the rock between the strain gages so that the surface rock is free to expand; (3) installation of a "flat-jack" (hydraulic pressure cell) in the slot; and (4) application of hydraulic pressure to the flat jack until the rock is restored to its original state of strain. The original stress in the rock is presumed to be equal to the final pressure in the flat jack. Woodruff strain rosette At any point on the surface of a stressed body, strains measured on each of three properly chosen intersecting gage lines make possible the calculation of the principal stresses at that point. Such gage lines, and the corresponding strains, are called a strain rosette. Roark strain sheet a. A skeleton drawing of a structure, as a roof of truss or a bridge, showing the stress to which each member will be subjected. b. A quarryman's term for granite sheets produced by compressive strain. strain-slip cleavage See: false cleavage; slip cleavage. Straits tin One of the purest commercial forms of tin (99.89% purity) produced from alluvial ores in Malaysia. strait work See: straight work strake a. A relatively wide launder or sluice set at a slope and covered with a blanket or corduroy for catching comparatively coarse gold and valuable mineral. See also: blanket strake b. A trough in which ore, gravel, etc., are washed; a launder. Standard, 2 c. The place where ore is assorted on the floor of a mine; a dressing floor. Standard, 2 3126

stranded Term for wire rope with one or more broken strands. Pryor, 3 stranded rope See: preformed rope; multistrand rope; flattened strand rope. stranskiite A triclinic mineral, (Zn,Cu)3 (AsO4 )2 ; blue; at Tsumeb, Namibia. strap a. A bar; a beam; a coal face bar. Mason b. A thin bar or metal plate, similar to a fishplate, used to secure together butt-jointed timber or steel members. Hammond strap brake A brake generally used on small winding engines. Sinclair, 5 strap fishplates Flattened bars of iron with holes punched through them for bolts. The holes are made somewhat larger than the bolt to permit rail expansion and contraction. Kiser strap-rope haulage A system of haulage (usually endless rope) in which the engine is installed on the surface, and the power is transmitted to the haulage drums at the pit bottom by means of a rope, which is known as a strap rope, or a driving rope. This rope merely transmits power and is distinct from the haulage rope. Nelson straps Thin metal support members from 5 to 20 ft (1.5 to 6 m) long are bolted to the mine roof to prevent roof deterioration between the bolts. Also known as roof mats or bacon skins. strata Plural of stratum. strata bolt

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A bolt or rod, from 2 to 5 ft (0.6 to 1.5 m) or more in length, set in drill holes in the strata for the support of curbs, skeleton tubbing, helical steel supports, etc., in shafts and staple shafts. In general, the weaker the ground, the longer the bolts. CF: roof bolting Nelson strata-bound Said of a mineral deposit confined to a single stratigraphic unit. The term can refer to a stratiform deposit, to variously oriented orebodies contained within the unit, or to a deposit containing veinlets and alteration zones that may or may not be strictly conformable with bedding. AGI strata control See: roof control strata gases These occur in the mineral deposit itself or in adjacent or nearby formations. Their origin may be in a particular formation in which they were laid down or formed subsequently by chemical action, or they may occasionally migrate into other formations, frequently because of release of pressure with mining. Water flow and rock porosity and fissures also allow gas migration. The principal strata gases are methane, carbon dioxide, nitrogen, sulfur dioxide, hydrogen sulfide, and radon. Hartman, 1 stratascope An apparatus inserted in the drill hole that permits engineers to make a visual inspection of the strata. Coal Age, 3 strata temperature The strata temperature is determined by the surface temperature, the diffusivity of the strata, and the emissivity of the surface. With rocks of high thermal conductivity, and thus, high diffusivity, as in metal mines, the increase in temperature with depth is small, i.e., the geothermic gradient is low. Where rocks have low thermal conductivity, as in coal measure strata, the geothermic gradient is steep. Syn: geothermic gradient strategic and critical material Materials that (a) would be needed to supply the military, industrial, and essential civilian needs of the United States during a national emergency, and (b) are not found or produced in the United States in sufficient quantities to meet such need. Strategic strategic mica 3128

Ruby and nonruby block mica. Good-stained or better qualities, grade No. 6 or larger; ruby-stained A/B quality, grade No. 6 or larger; ruby and nonruby film, first and second qualities, grade No. 4 and smaller; muscovite and phlogopite splittings; and phlogopite block of high heat quality. Skow strategic minerals Minerals essential to the national defense, for the supply of which, during war, we are wholly or in part dependent on foreign sources, and for which strict measures controlling conservation and distribution are necessary. For example, chromium- and tin-bearing minerals, quartz crystal, and sheet mica were some of the "strategic minerals" during World War II. straticulate Characterized by numerous very thin parallel layers, whether separable or not, either of sedimentary deposition (as a bed of clay) or of deposition from solution (as in a stalagmite or banded agate). AGI stratification a. The formation, accumulation, or deposition of material in layers; specif. the arrangement or disposition of sedimentary rocks in strata. See also: bedding b. A structure produced by deposition of sediments in strata; a stratified formation, or stratum. It may be due to differences of texture, hardness, cohesion or cementation, color, internal structure, and mineralogic or lithologic composition. AGI c. The state of being stratified; a term describing a layered or bedded sequence, or signifying the existence of strata. AGI d. A structure produced by deposition of sediments in beds or layers (strata), laminae, lenses, wedges, and other essentially tabular units. AGI stratification of methane In relatively unventilated cavities in coal mines, such as wastes, it is frequently found that the methane percentage or concentration is higher at roof level, lower at midheight, and least at floor level. This is termed stratification of methane. See also: combustible gases layer Nelson stratification plane See: bedding plane; stratification of methane. stratified Formed, arranged, or laid down in layers or strata; esp. said of any layered sedimentary rock or deposit. See also: bedded 3129

stratified rock See: sedimentary rock stratified rocks a. Derivative or stratified rocks may be fragmental or crystalline; those that have been mechanically formed are all fragmental; those that have been chemically precipitated are generally crystalline; and those composed of organic remains are sometimes partially crystalline. Syn: sedimentary rocks b. Rocks arranged in layers. Shell stratiform a. Said of a special type of strata-bound deposit in which the desired rock or ore constitutes, or is strictly coextensive with, one or more sedimentary, metamorphic, or igneous layers; e.g., beds of salt or iron oxide, or layers rich in chromite or platinum in a layered igneous complex. AGI b. Having the form of a layer, bed, or stratum; consisting of roughly parallel bands or sheets, such as a stratiform intrusion. Incorrect spellings: strataform, stratoform. AGI c. Bedded or layered. Bateman, 2 stratigrapher A geologist who specializes in stratigraphy. stratigraphic Pertaining to the composition, sequence, and correlation of stratified rocks. stratigraphic classification The arbitrary, but systematic arrangement, zonation, or partitioning of the sequence of rock strata of the Earth's crust into units with reference to the many different characters, properties, or attributes that the strata may possess (Hedberg, 1958). AGI stratigraphic control a. The influence of stratigraphic features on ore deposition, e.g., ore minerals selectively replacing calcareous beds. CF: structural control AGI b. The degree of understanding of the stratigraphy of an area; the body of knowledge that can be used to interpret its stratigraphy or geologic history. AGI stratigraphic geology See: stratigraphy 3130

stratigraphic heave a. For normal faults, the width of the gap between two parts of a disrupted bed, measured in the direction of the faulted bedding plane. Schieferdecker b. For reverse faults, the width of the overlap between two parts of a disrupted bed, measured in the direction of the faulted bedding plane. Schieferdecker stratigraphic hole A borehole drilled specif. to obtain a detailed record of the character and composition of the rock formation penetrated and not for the purpose of locating a mineral deposit. See also: record hole stratigraphic section See: geologic section stratigraphic separation The thickness of the strata that originally separated two beds brought into contact at a fault. Syn: stratigraphic throw stratigraphic sequence A chronologic succession of sedimentary rocks from older below to younger above, essentially without interruption; e.g., a sequence of bedded rocks of interregional scope, bounded by unconformities. AGI stratigraphic throw See: stratigraphic separation; throw. stratigraphy a. The science of rock strata. It is concerned not only with the original succession and age relations of rock strata but also with their form, distribution, lithologic composition, fossil content, geophysical and geochemical properties; indeed, with all characters and attributes of rocks as strata; and their interpretation in terms of environment or mode of origin, and geologic history. All classes of rocks, consolidated or unconsolidated, fall within the general scope of stratigraphy. Some nonstratiform rock bodies are considered because of their association with or close relation to rock strata. Syn: stratigraphic geology AGI b. The arrangement of strata, esp. as to geographic position and chronologic order of sequence. AGI c. The sum of the characteristics studied in stratigraphy; the part of the geology of an area or district pertaining to the character of its stratified rocks. AGI d. A term sometimes used to signify the study of historical geology. 3131

AGI e. That branch of geology that treats of the formation, composition, sequence, and correlation of the stratified rocks as parts of the Earth's crust. f. That part of the descriptive geology of an area or district that pertains to the discrimination, character, thickness, sequence, age, and correlation of the rocks of the district. stratometric survey A system whereby the in situ orientation of a core sample can be reproduced on the surface. A line is inscribed on the smoothed bottom of a borehole, and its azimuth relationship with a compass direction photographically recorded. When cored and removed from the borehole, the inscribed line can be used as a guide in orienting the core on the surface. Long stratum a. A bed or layer of rock; strata, more than one layer. Fay b. A layer greater than 1 cm in thickness. Pettijohn, 1 c. A tabular or sheetlike body or layer of sedimentary rock, visually separable from other layers above and below; a bed. The term is more frequently used in its plural form, strata. CF: lamina stratum plain See: stripped plain straw boss A generic term that sometimes includes all supervisory officials in a mine; a supervisor of a small group of miners usually working under a certified foreman. BCI stray current a. The use of direct current electric power in most coal mines presents a problem of corrosion caused by an electrolytic action on pipes. Where the track is employed as a conductor of electricity in this type of power system, the voltage drop produces a difference in potential between the track and earth or other structures that may serve as a conductor, such as pipelines. This condition may cause an electric current to flow in pipelines that form a parallel path with the track system. b. Electric current that is introduced in the earth by leakage of industrial currents. Schieferdecker streak a. The color of a mineral when scraped on a white ceramic plate. b. The color of a mineral powder usually obtained by scratching with steel or by rubbing on unglazed porcelain; it is more diagnostic for identification than bulk mineral color. c. A long, narrow, irregular stretch of land or water. d. A comparatively small and flattish or 3132

elongate sedimentary body, visibly differing from adjacent rock, but without the sharp boundaries typical of a lens or layer. e. A long, narrow body of sand, perhaps representing an old shoreline; a shoestring. f. The outcropping edge of a coal bed. streaking See: mineral streaking streak plate In mineral identification, a piece of unglazed porcelain, hardness about 7 on the Mohs scale, used for rubbing a sample to obtain its powder color, or "streak." stream-down sluice A sluice box placed to receive the material rejected from the tables of a dredge. stream gold Gold in placer deposits of alluvial origin. streaming a. Separating ore from gravel by the aid of running water. b. The working of alluvial deposits for the tin found in them; the washing of tin ore from the detrital materials; also, the reduction of stream tin. Standard, 2 c. A property that combustible gas possesses as a result of its low density. If, in a sloping roadway having a smooth roof, combustible gas is released from a break at the lower end, the gas will cling to the roof and stream upwards forming a pool at the upper end. Pure streaming and diffusion can occur where the air currents are sluggish or nonexistent, such as in wastes that have not collapsed, and roadways of large cross-sectional area in which the ventilation air speed is low. Roberts, 1 streaming potential Potential difference between a permeable diaphragm and the liquid passing through it. Pryor, 3 streamline A hypothetical line that shows the velocity direction of the fluid stream at each point along the line. Streamlines do not therefore cross each other. A set of streamlines charts the flow pattern. If the flow is steady then the streamline pattern does not change with time. If, however, the streamlines are continually changing shape the flow is unsteady. Roberts, 1 3133

streamline flow See: laminar flow streamlining This involves the placing of fairing around or over obstructions to airflow, in such a way as to change that flow from turbulent to laminar. Spalding stream tin Cassiterite occurring as waterworn pebbles in alluvial or placer deposits. CF: lode tin stream tube A tube of fluid the enveloping surface of which consists of streamlines. Roberts, 1 streamworks a. Corn. A name given by miners to alluvial tin deposits usually worked in the open air. b. A place where ore, generally tin ore, is washed from alluvial deposits. Standard, 2 strebbau Ger. The longwall system of coal mining. Fay street ell A pipe elbow with male threads on one end, female on the other. Nichols, 1 strek Corn. A trough for washing tin ore. A variation of strake. strengite a. An orthorhombic mineral, FePO4 .2H2 O ; variscite group; forms a series with variscite; may have Mn replacing Fe; dimorphous with phosphosiderite; pale red. b. The mineral group mansfieldite, scorodite, strengite, and variscite. strength The stress at which a rock ruptures or fails. strength of current 3134

The number of amperes flowing through a circuit. Analogous to the flow of gallons per minute in a water pipe. Crispin strength of materials The science that deals with the effects of forces in causing changes in the size and shape of bodies. (Crispin, 1964) stress In a solid, the force per unit area, acting on any surface within it, and variously expressed as pounds or tons per square inch, or dynes or kilograms per square centimeter; also, by extension, the external pressure that creates the internal force. The stress at any point is mathematically defined by nine values: three to specify the normal components and six to specify the shear components, relative to three mutually perpendicular reference axes. CF: strain shear stress. AGI stress analysis Determination of the stresses in the component parts of a structure when subjected to load. See also: photoelasticity stress circle A Mohr circle that reveals the distribution of stress. Hammond stress-corrosion cracking Failure by cracking under combined action of corrosion and stress, either external (applied) or internal (residual). Cracking may be either intergranular or transgranular, depending on metal and corrosive medium. ASM, 1 stress diagram See: stress-strain diagram stress difference The difference between the greatest and least of the three principal stresses. AGI stress envelope The zone of extra stress around a cylindrical hole being actually cylindrical in form. Syn: ring stress 3135

stress field The state of stress, either homogeneous or varying from point to point, in a given domain. AGI stress meter An instrument designed to measure pressure changes within rock as a result of mining operations. The instrument consists of a tongue of steel containing a groove filled with glycerin. When pressure is exerted upon the external surface of the tongue, the glycerin is partially squeezed from the groove and exerts pressure on a diaphram, which accordingly bulges outwards. A strain gage is cemented on the outer wall of the diaphragm, and as the curvature increases and the gage is strained, so does its resistance vary. Issacson stress mineral A term suggested for minerals such as chlorite, chloritoid, talc, albite, epidote, amphiboles, and kyanite, whose formation in metamorphosed rocks is favored by shearing stress. CF: antistress mineral stress-number (S-N) curve A curve obtained in fatigue tests by subjecting a series of specimens of a given material to different ranges of stress and plotting the range of stress against the number of cycles required to produce failure. In steel and many other metals, there is a limiting range of stress below which failure will not be produced even by an indefinite number of cycles. CTD stress ring Stress rings are force lines drawn on the cross section of an excavation to indicate the distribution of the additional stress in the rock caused by that excavation. Spalding stress solid The solid figure formed by surfaces bounding vectors drawn at all points of the cross section of a member and representing the unit normal stress at each such point. The stress solid gives a picture of the stress distribution on a section. Roark stress-strain curve A curve similar to a load extension curve, except that the load is divided by the original cross-sectional area of the test piece and expressed as tons or pounds per square inch, 3136

while the extension is divided by the length over which it is measured and expressed in inches per inch. See also: load-extension curve stress-strain diagram a. A graph on which is plotted stress vs. strain. Such a graph may be constructed in any test during which frequent or continuous measurements of both stress and strain are made. It is commonly constructed for the compression, tension, and torsion tests. It is usually necessary for the determination of deformation energy, elastic limit, modulus of elasticity, modulus of rigidity, proportional limit, and yield strength. It is often useful in determination of elongation, modulus of rupture, ultimate strength and related properties. Hunt b. The curve obtained by plotting unit stresses as ordinates against corresponding unit strains as abscissas. Syn: stress diagram Roark stress trajectory A line (in a stressed body) tangent to the direction of one of the principal stresses at every point through which it passes. Syn: isostatic stress zone This is the zone of additional stress in the rock surrounding and caused by a stoped area. Spalding stret The system of mining coal by headings or narrow work. See also: bord-and-pillar stretch A particular direction or course; as, the stretch of a coal seam. Standard, 2 stretcher a. A bar used for roof support on a roadway, which is either wedged against or pocketed into the sides of the roadway and not supported by legs or struts. TIME b. A bar fixed across a narrow working place or tunnel to support a rock drill. CTD c. A main backing deal or longitudinal bar in contact with three or more support bars or girders. Mason stretchers In shaft-sinking, the crosspieces holding the walling apart. Stauffer stretch fault 3137

See: stretch thrust stretch thrust A little-used term for a reverse fault formed by shear in the inverted limb of an overturned fold. Syn: stretch fault stria a. One of a series of parallel straight lines on the surface of a crystal, as in pyrite, indicative of an oscillation between two crystal forms; also, one of a series of such lines on the cleavage planes of a mineral, as of plagioclase, calcite, or corundum, indicative of polysynthetic twinning. Syn: striation b. Striation. AGI c. A minute groove or channel; a threadlike line or narrow band (as of color) esp. when one of a series of parallel grooves or lines, such as glacial stria. Webster 3rd striae a. A line or furrow generally seen on the walls of a lode or fault. Gordon b. Plural of stria. AGI striated Adj. of striation. striated cleavage A cleavage surface grooved with striae, e.g., plagioclase. striated crystal A crystal face grooved with striae; e.g., pyrite or quartz. striation a. See: stria b. One of multiple scratches or minute lines, generally parallel, inscribed on a rock surface by a geologic agent, i.e., glaciers, streams, or faulting. Syn: scratch c. The condition of being striated; the disposition of striations.--Adj: striated; striate. AGI striding level a. A spirit level so mounted that it can be placed astride a surveying instrument and so supported that it can be used for precise leveling of the horizontal axis of the instrument or for measuring any remaining inclination of the horizontal axis. AGI b. A demountable spirit level that can be attached to the telescope tube to level the line of sight. AGI 3138

strike a. The course or bearing of the outcrop of an inclined bed, vein, or fault plane on a level surface; the direction of a horizontal line perpendicular to the direction of the dip. CF: direction of strata; trace; trend. b. v. To find a vein of ore. n. A valuable discovery. Webster 3rd c. See: course; level course; fault strike. d. To withdraw supports. See also: line of bearing Syn: strike a lead strike a lead See: strike strike cut In separating blocks of stone in a quarry, the cut that is parallel to the strike of the rock strata. strike fault A fault whose strike is parallel to the strike of the strata. CF: dip fault; oblique fault. strike shift In a fault, the shift or relative displacement of the rock units parallel to the strike of the fault, but outside the fault zone itself; a partial syn. of strike slip. See also: shift strike-shift fault See: strike-slip fault strike slip a. In a fault, the component of the movement or slip that is parallel to the strike of the fault. CF: dip slip; oblique slip. Syn: horizontal displacement; horizontal separation. Partial syn: strike shift. AGI b. A horizontal component of the slip parallel with the fault strike. Schieferdecker strike-slip fault a. A fault on which the movement is parallel to the fault's strike. CF: dip-slip fault Syn: strike-shift fault b. A fault in which the net slip is practically in the direction of the fault strike. Syn: transcurrent fault strike valley 3139

A valley eroded in and parallel to the strike of the underlying rocks of a region. Syn: longitudinal valley strike working Where the dip of the coal seam is about 1 in 10 or less, the opencast method of working usually employed is to excavate along lines parallel to the outcrop. This is termed the strike or opencast method. See also: box-cut method striking Electrodepositing, under special conditions, a very thin film of metal that will facilitate further plating with another metal or with the same metal under different conditions. ASM, 1 striking hammer A quarryman's hammer for striking a rock drill. Standard, 2 striking plates Two horizontal timbers separated by striking wedges and supporting an arch center. The latter is lowered by slacking the wedges. Stauffer striking solution A dilute solution of silver cyanide, containing potassium cyanide, in which articles to be silver-plated are dipped before being immersed in the silver bath proper. Standard, 2 string a. Drilling bit, jars, drill stem, rope socket, and other tools connected to the lower end of a drilling cable in standard or percussion drilling. Also used for the rig and complete drilling equipment. Syn: drill string; string of tools. AGI b. A measurement of depth of a drill hole obtained by stringing over the length of cable from the drilling floor to the crown pulley on top of the derrick or mast. AGI c. A very small vein, either independent or occurring as a branch of a larger vein; a stringer. stringer a. A mineral veinlet or filament, usually one of a number, occurring in a discontinuous subparallel pattern in host rock. See also: stringer lode AGI b. A thin layer of coal at the top of a bed, separating in places from the main coal by material similar to that comprising the roof. c. A heavy timber or plank, usually horizontal but sometimes 3140

inclined, supporting other members of a structure; also, the horizontal crosspiece in square set timbering. d. See: roof stringer stringer lead A small orebody--generally, a vein leading to a more valuable one. AGI stringer lode A shattered zone containing a network of small nonpersistent veins. Syn: stringer zone stringer sets Mine timbering in which the caps reach across two or more sets in a drift or stope. Hess stringer zone See: stringer lode string loading Filling a drill hole with cartridges smaller in diameter than the hole, without slitting or tamping them. Nichols, 1 string of tools a. In a churn drill, the tools suspended on the drilling cable. Nichols, 1 b. The entire downhole drilling assembly. See also: string string survey a. A rough method of transferring points from upper to lower levels in very narrow steep workings by suspending strings from point to point and measuring offsets. The excavation dimensions may be similarly obtained. See also: plumbing b. The use of stretched strings in awkward underground workings to provide survey lines and a basis for offsets. In the lost-thread method of survey, a string or thread is paid out over a measuring device as a traverse line is walked. Pryor, 3 strip a. In mining, to remove the earth, rock, and other material from the mineral to be mined, usually by power shovels. Generally practiced only where the mineral lies close to the Earth's surface. BCI b. To remove from a quarry, or other open working, the overlying earth and disintegrated or barren surface rock. See also: baring c. To mine coal, 3141

alongside a fault, or barrier. d. To fill prepared coal from a coal face. See: stripping Syn: stripping a mine Stripa process a. A heavy medium process developed in Sweden for concentrating iron, copper, and chromite ores. The rate of supply of water over a shaking bed of wet sand effects the separation of heavy and light fractions. b. A method of gravity treatment of coarse sands, in which feed is shaken along horizontal launder and at the same time kept in teeter by hydraulic water. Constituent minerals stratify into separable layers. Pryor, 3 strip-borer drill A skid- or crawler-mounted drill operated by electric motor or diesel engine. It is used at quarry or opencast sites for drilling horizontal blast holes 3 to 6 in (7.6 to 15.2 cm) in diameter, and up to 100 ft (30 m) in length, without the use of flush water. It cannot penetrate strong strata. Nelson stripe The series of bands of variation in color or texture in a rock mass, or the course of the planes of such bands, as indicative of the course of the bedding plane when that is otherwise obscure. See also: ribbon Standard, 2 Stripkolex Trademark for a dynamite for coal stripping operations. CCD, 2 strip mine A stripping; an opencut mine in which the overburden is removed from a coalbed before the coal is taken out. See also: opencast; opencut; openpit mine. Hess strip mining The mining of coal by surface mining methods as distinguished from the mining of metalliferous ores by surface mining methods; the latter is commonly designated as openpit mining. See also: opencast method; openpit mining; surface mining. Woodruff strip packing An arrangement of alternate packs and wastes built in a direction parallel to the gate roads in longwall conveyor mining. A common practice is to allow 5-yd (4.5-m) wastes between 4-yd (3.7-m) packs, or both are made 5 yd wide. The dimensions vary with local conditions. See also: stowing method; double packing; single packing. Nelson 3142

stripped illite See: degraded illite stripped plain A plain composed of flat-lying or gently tilted sedimentary rocks from which sediments have been removed down to some resistant bed that has controlled the depth of erosion. CF: dip slope stripper a. A nearly depleted well whose income barely exceeds operating cost of production. Wheeler, R.R. b. In the quarry industry, a laborer who cleans up dirt left by the power shovel in stripping overlying ground from rock, using a shovel and wheelbarrow. DOT stripping a. The removal of earth or nonore rock materials as required to gain access to the desired coal, ore, or mineral materials; the process of removing overburden or waste material in a surface mining operation. b. The earth, rock, or soil so removed. c. The loading or clearing away of coal from a longwall face after shotfiring. Nelson d. Opencast mining. Nelson e. See: stripping the quarry; strip. f. In chemical extraction of minerals, treatment of pregnant solution to remove dissolved values. Pryor, 3 stripping a gutter Removing the headings from off the wash dirt, which is left undisturbed. stripping a jig Aust. The forming of a jig, by enlarging a cut-through on an incline. See also: jig stripping a mine a. See: strip b. Robbing a mine of its best ore. stripping area In stripping operations, an area encompassing the pay material, its bottom depth, the thickness of the layer of waste, the slope of the natural ground surface, and the steepness of the safe slope of cuts. Nichols, 1 stripping a shaft 3143

a. Taking out the timber from an abandoned shaft. b. Trimming or squaring the sides of a shaft. stripping-pit limits The strip area that includes area of pay material plus enough area beyond the limits of the ore pit to provide for a bench. The total volume of stripping will be that vertically above the limits of the ore pit plus that outside of the ore pit necessary to maintain safe strip-pit slopes and benches and provide working approaches to the pit. Jackson, 3 stripping ratio The unit amount of spoil or overburden that must be removed to gain access to a unit amount of ore or mineral material, generally expressed in cubic yards of overburden to raw tons of mineral material. stripping salt See: abraumsalze stripping shovel A shovel with an esp. long boom and stick that enables it to reach further and pile higher. Nichols, 2 stripping-shovel operator In bituminous coal mining, one who operates a power shovel in a strip mine to strip back overlying ground and to load coal into cars. Also called coal-loading-shovel engineer; loading-shovel engineer. Syn: boom cat DOT stripping solution In solvent extraction, the aqueous solution used to re-extract the metal from the pregnant solution. stripping system The removal of the overburden and mining of the ore in one or more benches, the ore face being broken by blasting and the broken ore loaded by hand, shoveling machine, or steam shovel. The name "terrace or bench open-pit working" has been suggested. stripping the quarry

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The removal of all dirt and unwanted disintegrated material from the quarry face. See: stripping strip pit A coal or other mine worked by stripping. An open-pit mine. strip sample A sample, making a notch or groove, cut from roof to floor of a coal seam, or from hanging wall to footwall of a vein. See also: channel sample strip thrust See: decollement stroke a. The distance traveled by a piston in a pump or a piston in a hydraulic-feed mechanism on a drill. Long b. The maximum distance a piston moves within a cylinder before the direction of its travel is reversed. Long c. The distance a churn-drill stem and bit are raised for dropping while drilling. Long stroke of crusher The difference between the open and closed positions measured at the throat of the crusher. For small crushers it is about 3/8 to 3/4 in (0.95 to 1.9 cm), and for large crushers from 1 to 2 in (2.5 to 5 cm). Also called throw of crusher. Newton, 2 stromatite A type of mixed rock or chorismite in which the units of the fabric (granitic material and metamorphic or sedimentary rock) form a system of layers, strata, or bands so intricately united that the whole rather than the individual layers constitutes the geological field unit. stromatolite A structure produced by sediment trapping and/or precipitation as a result of the growth of cyanophytes (blue-green algae). It has a variety of gross forms, from nearly horizontal to markedly columnar, domal, or subspherical. Syn: algal stromatolite; stromatolith. AGI stromatolith

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a. See: stromatolite b. A complex, sill-like igneous intrusion that is interfingered with sedimentary strata. AGI stromeyerite An orthorhombic mineral, AgCuS ; metallic; soft; steel gray with blue tarnish; sp gr, 6.2 to 6.3; in copper-silver veins; a source of copper and silver. Syn: silver-copper glance strong a. Hard and thick; said of dikes. Standard, 2 b. Important or rich; said of veins. Standard, 2 c. Referring to the character of bind, meaning that the argillaceous material is largely mixed with the arenaceous or siliceous material. d. Scot. Hard, not easily broken, e.g., strong coal, strong blaes. e. Said of large or important mineral veins or faults. AGI strongback A heavy timber or metal beam or bar for taking a strain. Webster 3rd strong lode A large, persistent lode. At Alston moor, England, applied to lodes lying in a fault plane in which the difference of level between similar strata is considerable. strontianite An orthorhombic mineral, 4[SrCO3 ] ; aragonite group; in hydrothermal veins associated with limestones, less commonly with eruptive rocks in California, New York, Washington, Germany, and Mexico; a source of strontium. Syn: carbonate of strontium strontioginorite A monoclinic mineral, (Sr,Ca)2 B14 O23 .8H2 O; forms a series with ginorite. CF: ginorite strontium A silvery-white, alkaline-earth metal. Symbol, Sr. It does not occur naturally; found chiefly as celestite (SrSO4 ) and strontianite (SrCO3 ). Major use at present is for color television picture tubes. Handbook of Chemistry and Physics, 3 strontium-apatite A hexagonal mineral, Sr5 (PO4 )3 (OH) ; apatite group; vitreous; light green; in sugary albite filling interstices between crystals of aegirine and eckermannite in veins in alkalic pegmatites from Inagil massif, southern Yakutia, Russia. 3146

strontium minerals Used primarily in television face-plate glass, in ceramic ferrites, and in pyrotechnics. The United States imports most of its celestite, the chief source of strontium, from Mexico and Germany. strontium stannate SrSnO3 ; sometimes used as an additive to titanate bodies, one result being a decrease in the Curie temperature. Dodd strontium titanate SrTiO3 ; isometric; and melting point, 1,670 degrees C. Used in ceramic dielectric bodies, either alone or in combination with barium titanate or other titanates. Lee; Handbook of Chemistry and Physics, 2 strontium zirconate SrZrO3 ; melting point, 2,700 degrees C; sp gr, 5.48. Sometimes used in small amounts (3% to 5%) in ceramic dielectric bodies, one effect being to lower the Curie temperature. Dodd struck capacity a. The capacity of a mine car, tram, hoppit, or wagon to the flat surface at the edges; i.e., the volume of water it would hold if of watertight construction. Nelson b. In scraper loading, the maximum volume of liquid that the bowl can hold. CF: heaped capacity struck out Corn. The termination of a vein or lode by a fault. structural Of or pertaining to rock deformation or to features that result from it. AGI structural analysis The initial stage of structural design, in which all the forces carried by the various parts of a structure are determined. Hammond structural basin

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A low area in the Earth's crust, of tectonic origin, in which sediments have accumulated, e.g., a circular centrocline such as the Michigan Basin, a fault-bordered intermontane feature such as the Bighorn Basin of Wyoming, or a linear crustal downwarp such as the Appalachian Basin. Such features were drainage basins at the time of sedimentation, but are not necessarily so today. AGI structural bottoming See: bottoming structural color See: pseudochromatism structural control The influence of structural features on ore deposition, e.g., ore minerals filling fractures. CF: stratigraphic control structural dome See: dome structural drilling Drilling done specif. to obtain detailed information delineating the location of folds, domes, faults, and other subsurface structural features undiscernible by studying strata exposed at the surface. CF: structure drilling structural fabric See: fabric structural geology The branch of geology that deals with the form, arrangement, and internal structure of the rocks, and esp. with the description, representation, and analysis of structures, chiefly on a moderate to small scale. The subject is similar to tectonics, but the latter is generally used for the broader regional or historical phases. AGI structural high High point of a structure. See also: high structural load 3148

The load due to the structure itself as distinguished from the imposed load. Crispin structural log A record of the breaks, fractures, faults, and physical properties of rocks within a formation. structural low Low point of a structure. See also: low structural petrology The analysis of fabric on the thin-section or micro scale. It includes the study of grain shapes and relationships (microstructure) and the study of crystallographic preferred orientations. The transmission electron microscope is also employed to examine the substructures of deformed crystals. AGI structural plain See: stripped plain structural relief a. The vertical distance between stratigraphically equivalent points at the crest of an anticline and in the trough of an adjacent syncline. AGI b. More generally, the difference in elevation between the highest and lowest points of a bed or stratigraphic horizon in a given region. AGI structural steelwork Rolled steel sections or other fabricated members assembled to form structural frames by riveting, welding, bolting, or a combination of all three. Hammond structural terrace a. A local shelf or steplike flattening in otherwise uniformly dipping strata, composed of a synclinal bend above and an anticlinal bend at a lower level. AGI b. A terracelike landform controlled by the structure of the underlying rocks; esp. a terrace produced by the more rapid erosion of weaker strata lying on more resistant rocks in a formation with horizontal bedding. AGI structural valley A valley that owes its origin or form to the underlying geologic structure. AGI 3149

structural vitrain See: phyllovitrinite structure a. The parts or members of any building that carry the loads and transmit them to the foundations. Structures in mining areas may suffer some subsidence and are designed accordingly. Nelson b. Geologically, the disposition of the rock formations; i.e., the broad dips, folds, faults, and unconformities at depth. Nelson c. In petrology, one of the larger features of a rock mass, like bedding, flow banding, jointing, cleavage, and brecciation; also, the sum total of such features. CF: texture d. See: soil structure structure contour A contour that portrays a structural surface such as a formation boundary or a fault. Syn: subsurface contour structure-controlled shoot An ore shoot that is localized by geologic structure. Changes in strike and dip of fissures are favorable sites for ore shoots. structure drilling a. Exploratory drilling to determine the geological structure with reference to the coal or minerals sought. Rotary or diamond drilling is usually employed to yield cores at key horizons. Nelson b. A form of drilling practiced in the Lake Superior iron district to sample soft iron formations by countercirculation-wash boring methods. CF: structural drilling structure section A diagram to show the observed geological structure on a vertical face or, more commonly, to show the inferred geological structure as it would appear on the side of a vertical trench cut into the earth. The vertical scale is often exaggerated. structure test hole A hole drilled for geologic structure alone, although other types of information may be acquired during the drilling. This type of hole is drilled to a structural datum, which is normally short of known or expected producing zones. See also: seismic shothole; slim hole. Williams strunzite 3150

A triclinic mineral, MnFe2 (PO4 )2 (OH)2 .6H2 O ; pseudomonoclinic; forms straw-yellow radiating fibers from the alteration of triphylite. strut a. A piece of wood or steel inserted between each pair of steel or timber supports on roadways to resist buckling and to maintain the proper spacing between the sets. Nelson b. A mine prop to sustain compression, whether vertical or inclined. Zern c. An inside brace. Nichols, 1 d. A diagonal brace between two legs of a drill tripod or derrick; also, a vertical-compression member in a structure or in an underground timber set. Long strut tenon A tenon, such as is used on a diagonal piece or strut, usually on heavy timbers. Crispin Struve ventilator A pneumatic ventilating apparatus consisting of two vessellike gas holders, which are moved up and down in a tank of water. By this means, air is sucked out of a mine. Zern struvite An orthorhombic mineral, (NH4 )MgPO4 .6H2 O ; soft; has one perfect and one good cleavage. stub entry A short, narrow entry turned from another entry and driven into the solid coal, but not connected with other mine workings; a dead end. Syn: dead end Stub's gage A gage for measuring the size of wire. Also known as Birmingham gage. Crispin stub switches Switches used to some extent on narrow-gage industrial tramways; consisting of a pair of short switch rails, held only at or near one end and free to move at the other end to meet rails of straight or diverging track. Urquhart stud a. A bolt having one end firmly anchored. Nichols, 1 b. A threaded rod or a bolt without a head. Hammond c. An upright beam or scantling as in the framework of a dwelling. Crispin 3151

studdle a. A strong crossbeam in a shaft collar set. Nelson b. Corn. A prop to support the middle of a stull. c. A distance piece between successive frames of timbering. d. A vertical member of a shaft-timber set. The sets are placed at each corner and at the intersection of the dividers and the wallplates. e. An upright prop supporting a platform in a mine, usually one of a set of four. Standard, 2 stud-type chain A roller chain in which the inner (block) links are connected solidly by nonrotating bushings. Nichols, 1 stuffed a. A mineral having foreign ions in large interstices in its structure; e.g., garnet with an extra cation. b. A mineral structure derived from another by coupled replacement of a cation with two cations of lower valence, one of which occupies a structural cavity; e.g., feldspars derived from coesite by aluminum ions replacing silicon in the framework coupled with alkali or alkali earth ions in structural cavities. stuffed mineral A mineral having large interstices in its structure may accommodate various foreign ions in these holes; such a mineral is then said to be stuffed. The stuffing may have considerable consequences on the stability of the mineral. AGI stuffing box A chamber designed to contain packing and to maintain a fluid-tight joint about a piston rod where it enters a cylinder or around a drill rod where it enters the casing at the collar of a borehole. Long stull a. A timber prop set between the walls of a stope, or supporting the mine roof. b. A timber platform on which valueless rock or mineral is deposited. c. Corn. A platform (stull-covering) laid on timbers (stullpieces), braced across a working from side to side, to support workers or to carry ore or waste. d. A round timber used to support the sides or back working of a mine. Mersereau, 2 stull covering A platform resting on stulls in a stope as a stage for miners or for holding rock or mineral. Nelson 3152

stulled stopes Stopes in which the roof is supported by stulls, square-set timbering, or concrete columns. Stoces stull piece A piece of timber placed slanting over the back of a level to prevent rock falling into the level from the stopes above. Standard, 2 stull stoping The walls of narrow veins frequently are supported by stull timbers placed between the foot and hanging walls, which constitute the only artificial support provided during the excavation of the stopes. Stulls may be placed at irregular intervals to support local patches of insecure ground, in which case the stopes are virtually open stopes. Sometimes the stulls are placed at regular intervals both along the stope and vertically, in which case stull stoping should be considered a distinctive method. stull timbering The support of walls in shrinkage stoping by setting stulls. Nelson stulm An approx. horizontal passageway into a mine; an adit. Taken from the German term stollen. Webster 3rd stump a. Entry pillars; small portion of room pillars left for pick mining. BCI b. A small pillar of coal left between the gangway or airway and the breasts to protect these passages; any small pillar. Fay c. A narrow pillar of coal. Lewis stumper A narrow heavy dozer attachment used in pushing out stumps. Nichols, 1 stump prop Short posts set under the crown bars of a tunnel. Stauffer stump pulling See: pillar robbing 3153

stunning A quarry worker's term for the formation of fractures caused by the cutting bars of a channeling machine striking the rock with excessively heavy blows. Sturtevant balanced rolls Rolls in which all four boxes are moveable in position by springs to divide the thrust whenever the springs yield and thus reduce internal stresses. Liddell Sturtevant grinder A disk grinder in which one disk is stationary and the other rotates. The stationary disk is moved out of center from time to time, so that any groove that forms can be ground out. Liddell Sturtevant ring roll crusher A crusher similar to the Kent roller mill. Liddell Sturtevant roll jaw crusher A crusher in which the motion of the upper part of the jaws is like that of the Dodge crusher, while the lower parts of the jaws, of cylindrical surfaces of varying radii, grind the ore between them. Liddell Sturzelberger iron reduction process A process evolved for dealing with pyrite roasting residues rich in zinc (8% to 10%). The direct reduction takes place in a short rotary drum that has a rammed tar-dolomite lining. Lime is added to produce a highly basic slag; the pyrite cinders, precalcined, are mixed with coke breeze and fired with pulverized coal burners. The zinc is recovered from the waste gases. The drum works discontinuously in 7-h heats, and the capacity of such a plant is limited in comparison with a blast furnace. The product is a liquid pig iron. Osborne Stygian deposits A general term for ore deposits formed underground by waters of atmospheric origin. stylolite A surface or contact, usually in carbonate rocks, that is marked by an irregular and interlocking penetration of the two sides: the columns, pits, and teethlike projections on one side fit into their counterparts on the other. As usually seen in cross section, it 3154

resembles a suture or the tracing of a stylus. The seam is characterized by a concentration of insoluble constituents of the rock; e.g., clay, carbon or iron oxides, and is commonly parallel to the bedding. Etymol: Greek stylos, pillar, + lithos, stone. Syn: crowfoot; suture joint. AGI stylotypite Syn: tetrahedrite appreciable silver. Styrian jade Pseudophite, a compact massive variety of clinochlore. stythe a. Gr. Brit. Carbonic acid gas, often found in old workings and given off in most shallow mines. Also spelled stithe. Tomkeieff b. See: blackdamp subA prefix denoting under, below, or less than. Containing only a relatively small proportion or less than the normal amount of (such) an element or radical; not used systematically. Webster 3rd subaeration cells See: sub-A flotation cells subaeration method In flotation, a method employing an impeller, of which the principal function is to keep the pulp in suspension, and a port for admission of air below the surface of the pulp, this port of entry being in the vicinity of the impeller. Gaudin, 2 subaerial Said of conditions and processes, such as erosion, that exist or operate in the open air on or immediately adjacent to the land surface; or of features and materials, such as eolian deposits, that are formed or situated on the land surface. The term is sometimes considered to include fluvial. CF: subaqueous; subterranean. See also: surficial AGI sub-A flotation cells Those in which air is supplied direct to a rotary agitator, mechanically driven, situated at depth in the flotation cell so that air is churned with ore pulp. Two types are (1) that in 3155

which air is drawn down by impeller; and (2) that in which low-pressure air is blown in. Syn: subaeration cells subalkalic a. A group term applied to rocks of the tholeiitic and calc-alkaline series. AGI b. Said of an igneous rock that contains no alkali minerals other than feldspars. AGI c. Used to describe an igneous rock of the Pacific suite. AGI subangular Somewhat angular, free from sharp angles but not smoothly rounded; specif. said of a sedimentary particle showing definite effects of slight abrasion, retaining its original general form, and having faces that are virtually untouched and edges and corners that are rounded off to some extent. AGI subaqueous Said of conditions and processes, or of features and deposits, that exist or are situated in or under water, esp. freshwater, as in a lake or stream. CF: subaerial subaqueous disposal A mine waste management practice whereby mill tailings or mine waste rock are emplaced under a body of water to minimize sulfide oxidation and acid formation, and eliminate airborne particulate pollution. If a natural sedimentation basin is utilized, erosion hazards inherent to subaerial impoundments are eliminated. subaqueous mining Surface mining in which the material mined is removed from the bed of a natural body of water. AIME, 2 subarid See: semiarid subarkose A sandstone that does not have enough feldspar to be classed as an arkose, or a sandstone that is intermediate in composition between arkose and pure quartz sandstone. CF: arkose subaudible noise 3156

Noise the intensity of which is so low that it can only be detected by means of a microphone and suitable amplifying equipment. How these subaudible noises, or microseisms, originate has not definitely been established, but it is believed that they are produced by incipient cracking or intermovement between fragments of crystalline aggregates in the rock. It has been found that almost invariably a period of increased microseismic activity precedes any large-scale ground movement or failure. Issacson subbase a. A layer of material laid on the natural ground under a road base for purposes of strengthening. CF: subgrade b. The lowest part of a base. Crispin subbituminous A coal The rank of coal, within the subbituminous class of Classification D 388, such that, on the moist, mineral-matter-free basis, the gross calorific value of the coal in British thermal units per pound is equal to greater than 10,500 (24.42 MJ/kg) but less than 11,500 (26.75 MJ/kg) and the coal is nonagglomerating. ASTM subbituminous B coal The rank of coal, within the subbituminous class of Classification D 388, such that, on the moist, mineral-matter-free basis, the gross calorific value of the coal in British thermal units per pound is equal to greater than 9,500 (22.10 MJ/kg) but less than 10,500 (24.42 MJ/kg) and the coal is nonagglomerating. ASTM subbituminous C coal The rank of coal, within the subbituminous class of Classification D 388, such that, on the moist mineral-matter-free basis, the gross calorific value of the coal in British thermal units per pound is greater than 8,300 (19.31 MJ/kg) but less than 9,500 (22.10 MJ/kg), and the coal is nonagglomerating. ASTM subbituminous coal a. Black lignite or lignitic coal. Fay b. Coal of rank intermediate between lignite and bituminous. In the specifications adopted jointly by the American Society for Testing and Materials (D388-38) and the American Standards Association (M20.1-1938), subbituminous coals are those with calorific values in the range 8,300 to 13,000 Btu (19.3 to 30.2 MJ/kg), calculated on a moist, mineral-matter-free basis, which are both weathering and nonagglomerating according to criteria in the classification. Stokes subconchoidal Partially or indistinctly conchoidal. Webster 3rd 3157

subcooling Cooling of a liquid refrigerant below the condensing temperature at constant pressure. Strock, 2 subcritical area of extraction An area of goaf too small to cause full subsidence at the surface. See also: critical area of extraction subdeposit level See: group level subdrift caving See: sublevel caving subdrifting and caving See: top slicing combined with ore caving subdrilling See: underdrilling subduction The process of one lithospheric plate descending beneath another. See also: obduction subduction zone A long, narrow belt in which subduction takes place; e.g., along the Peru-Chile trench or in the volcanic arc belts of the western Pacific Ocean. AGI subeconomic resources The part of identified resources that does not meet the economic criteria of reserves and marginal reserves. USGS, 2 suberain A subvariety of provitrain in which the corky origin of the cellular structure is microscopically visible. CF: periblain; xylain. AGI 3158

suberinite a. A variety of provitrinite characteristic of suberain and consisting of corky tissue. AGI b. A maceral of brown coal and lignite derived from the suberin layer in corkified cell walls of some Mesozoic and younger plants. CF: periblinite; xylinite; telinite. AGI subfeldspathic a. Said of a mature lithic wacke (or lithic graywacke) in which quartz grains and fragments of siliceous and argillaceous rocks predominate, and feldspars make up less than 10% of the rock and may be altogether lacking. Such rocks have also been called subgraywackes. AGI b. Said of a mature lithic arenite containing abundant quartz grains and fragments of the more stable rocks (such as cherts), and less than 10% feldspar grains. AGI subgrade A layer, stratum, or material immediately beneath some principal surface; specif. a layer of earth or rock that is graded to receive the foundation of an engineering structure. Often it is the soil or natural ground that is prepared and compacted to support, and that lies directly below, a road, pavement, building, airfield, or railway. CF: subbase subgrade surface The surface of the earth or rock prepared to support a structure or a pavement system. ASCE subgraywacke The most common type of sandstone, intermediate in composition between orthoquartzite and graywacke (Pettijohn, 1957). Composition is typically 30% to 65% quartz and chert, less than 15% clay matrix, more than 25% unstable materials such as feldspar grains and rock fragments, and voids or mineral cement exceeding the amount of clay matrix. The rock is lighter colored and better sorted, and has less matrix, than graywacke. CF: graywacke subhedral a. Said of a mineral grain that is bounded partly by its own rational faces and partly by surfaces formed against preexisting grains as a result of either crystallization or recrystallization. AGI b. Said of the shape of such a crystal, intermediate between euhedral and anhedral. AGI subhydrous macerals 3159

Macerals having a low hydrogen content, such as fusinite. Tomkeieff subincline An inclined shaft along the footwall of a reef on the Rand. It develops and extracts ore from areas below the main haulage level. See also: staple shaft subindividual One of the small crystals that often unite in parallel growths to build up larger crystals of the same general habit. Standard, 2 subjacent Said of a stratum situated immediately under a particular higher stratum or below an unconformity. Ant: superjacent. Syn: underlying subjective brightness The subjective brightness of a surface is determined by two factors, the light flux radiated from the surface and the sensitivity of the eye under the conditions in which the surface is seen. The sensitivity of the eye is partly controlled by the contrasts presented over the visual field, but is mainly dependent on its adaptation brightness level. Roberts, 2 sublevel a. A secondary level for working ore in top slicing and sublevel caving; a companion heading. Nelson b. An intermediate level opened a short distance below the main level; or, in the caving system of mining, 15 to 20 ft (4.6 to 6.1 m) below the top of the orebody, preliminary to caving the ore between it and the level above. See also: sublevel stoping; caving system. sublevel backstoping See: sublevel stoping sublevel caving a. A stoping method in which relatively thin blocks of ore are caused to cave by successively undermining small panels. The ore deposit is developed by a series of sublevels spaced at vertical intervals of 18 to 25 ft or 30 ft (5.5 to 7.6 m or 9.1 m) and occasionally more. Usually only one or two sublevels are developed at a time, beginning at the top of the orebody. The sublevels are developed by connecting the raises with a longitudinal subdrift from which timbered slice drifts are driven right and left opposite 3160

the raises to the ore boundaries or to the limits of the block. Usually alternate drifts are driven first, and caving back from them is begun and continued while the intermediate slices are being driven. The caving is begun at the ends of the slices by blasting out cuts and retreating in the same manner toward the raises. The broken and caved ore formerly was shoveled into cars and trammed to the raises, but in recent years it is dragged to the raises by power scrapers. Successively lower sublevels are developed and caved back until the entire block has been mined. This method is intermediate between block caving and top slicing, since part of the ore is mined as in top slicing and part is caved. See also: top slicing combined with ore caving b. Similar to top slicing from which it is thought to have been developed. The general plan of operations is to mine every other slice by driving crosscuts (slice drifts) from 18 to 36 ft (5.5 to 11.0 m) apart. The ore between the crosscuts as well as that in the slice above is then mined, thus causing the overlying material to cave. The method is applicable to irregular and steeply dipping orebodies that cannot be worked by top slicing. The present tendency is to sink vertical shafts in the footwall rather than inclined shafts as formerly done. Also called subdrift caving. Lewis sublevel drive A drive often made in a section, esp. in gently inclined deposits, that divides the deposit into narrower panels and zones. They are narrower, and the support and equipment for them is more simple than that required in level drives. Stoces sublevel method See: sublevel stoping sublevel slicing See: top slicing combined with ore caving; sublevel stoping. sublevel stoping a. In this mining method, the ore is excavated in open stopes, retreating from one end of the stope toward the other. The orebody is developed first by a series of sublevel drifts above the main haulage level. The sublevels are connected by a starting raise at one end of the stope and by a passageway raise for entrance to them and the stope face at the other end. Chute raises connect the haulage level to the lowest sublevel, at which the tops of the chute raises are belled out to form mill holes. Beginning at the starting raise the ore is benched down from the sublevels; the broken ore falls into the mill holes, where it is drawn off through the chutes. The stope face is kept nearly vertical as it is benched backward toward the passageway raise. b. A mining method involving overhand, underhand, and shrinkage stoping. Its characteristic feature is the use of sublevels. The sublevels are worked simultaneously, the lowest on a given block being farthest advanced and the subs above following one another at short intervals. The 3161

uppermost sublevel underneath the cover is partly caved. The caved cover follows down upon the caved ore. The broken ore is in part drawn from the level, and a part remains in the stope to give lateral support to the walls and to prevent admixture of cover and ore. The breaking faces are developed by crosscuts, which are extended from wall to wall from the end of the sublevel. The method can also be looked upon as a retreating method, the orebody being worked from the top down and the individual blocks upon a given level being worked from their ends to the center. Modifications of this method are chamber-and-pillar system; chambers without filling; combination of subslicing and stoping; drift stoping; filling system; Mitchell slicing system; pillar robbing; pillar robbing and hand filling; room-and-pillar system; square work and caving; square work, pillar robbing, and hand filling; sublevel back stoping; sublevel method; sublevel slicing system; substoping. c. A method of mining best adapted to steeply inclined deposits that have strong ore and strong walls. The ore is usually blocked out by two horizontal drifts separated vertically by 100 to 200 ft (30 to 61 m) and raises between the two horizontal drifts, the latter separated by comparable distances. Vertical pillars may be left between stopes on the same level, and horizontal ones to support the main haulage. After the main blocks of ore have been completely mined, it is common practice to rob the pillars, and the walls of the stope may collapse after the pillars have been robbed. Lewis d. Of lodes, open-stope mining in which ore is blasted and drawn through footwall openings to a gathering level in the country rock below. Used with strong containing walls and wide lodes. Pryor, 3 e. Of massive deposits, working simultaneously of a series of sublevels echeloned vertically, the lowest leading and the uppermost being partly caved as the covered rock descends. Pryor, 3 f. See: sublevel backstoping; substoping. sublimate a. A coating or deposit formed in a glass tube or on charcoal as a result of heating certain minerals. b. The product of sublimation. CTD c. A solid deposit by a gas or vapor; commonly used in reference to material deposited by volcanic gases. AGI sublimation a. The process by which a solid substance vaporizes without passing through a liquid stage. CF: evaporation b. The process of ore deposition, as of sulfur or mercury, by vapors; the volatilization and transportation of minerals followed by their deposition at reduced temperatures and pressures. Sublimation deposits are generally associated with fumarolic activity. AGI sublimation theory The theory that a vein was filled first with metallic vapors. sublime

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To cause to pass from the solid state to the vapor state by the action of heat and again to condense to solid form. submarginal land Generally means land not very good for farming. Tens of millions of tons of coal are removed each year by stripping the surface of this type land. Kentucky submarine blast A charge of high explosives fired in boreholes drilled in the rock underwater for dislodging dangerous projections and deepening channels. Fay submarine canyon An elongated, steep-walled cleft running across or partially across the Continental Shelf, the continental borderland and/or slope, the bottom of which grades continually downwards. AGI submarine drilling Drilling from the surface of a body of water with a drill mounted on an anchored tower, platform, or barge. Long submarine mines Workings that follow the mineral under the sea. Syn: undersea workings Zern submarine packing Special heavy paper shells in which dynamite is packed in underwater blasting. Carson, 2 submarine throat A throat with the fluid level below the bottom of a melter. See also: throat submerged unit weight The weight of the solids in air minus the weight of water displaced by the solids per unit of volume of soil mass; the saturated unit weight minus the unit weight of water. See also: unit weight submergence 3163

a. In an air lift, the distance below the water level, during pumping, at which the air picks up water. Lewis b. A term that implies that part of a land area has become inundated by the sea but does not imply whether the sea rose over the land or the land sank beneath the sea. AGI submetallic luster A luster between metallic luster and nonmetallic luster. Hurlbut subophitic Said of the texture of an igneous rock in which the feldspar crystals are approx. the same size as the pyroxene and are only partially included by them. The term ophitic generally includes such textures. AGI suboutcrop a. S. Afr. Rock that would have been the outcrop on the surface, but is covered by other formations. Beerman b. Area of intersection of a geologic feature with the surface of bedrock beneath the regolith. Hawkes, 1 subsample In coal and coke sampling, part of the sample consisting of a number of increments spaced evenly over the unit. BS, 2 subsequent ore deposit See: epigenetic subsidence The sudden sinking or gradual downward settling of the Earth's surface with little or no horizontal motion. The movement is not restricted in rate, magnitude, or area involved. Subsidence may be caused by natural geologic processes, such as solution, thawing, compaction, slow crustal warping, or withdrawal of fluid lava from beneath a solid crust; or by human activity, such as subsurface mining or the pumping of oil or groundwater. See also: shift; cauldron subsidence; settlement. Syn: land subsidence; bottom subsidence. AGI subsidence area The area affected by subsidence over areas where minerals or other substances have been removed. The area is larger than the mined-out area below. AGI 3164

subsidence basin A shallow troughlike depression at the surface resulting from subsidence. Nelson subsidence break A fracture in the rocks overlying a coal seam or mineral deposit as a result of its removal by mining operations. The subsidence break usually extends from the face upward and backward over the unworked area. Nelson subsidence factor Full subsidence expressed as a fraction of the thickness of coal seam extracted. See also: maximum subsidence subsidiary fracture Minor breaks sometimes developed in the rocks along a fault plane. They often indicate the general direction of movement and were caused by differential tension in the rocks contiguous to the main fault plane. See: tension fracture subsidiary survey An underground survey made to determine the position of a faceline or goafline or some other specific feature. BS, 7 subsidiary transport The conveying or haulage of coal or mineral along the working faces and outward to a junction or loading point. See also: main transport; underground haulage. Nelson subsieve analysis In powder metallurgy, size distribution of particles all of which will pass through a 44mu m (No. 325) standard sieve, as determined by specified methods. ASM, 1 subsieve material In mineral dressing, material finer than 400 mesh that must be sized by elutriation in rising currents of water or air, by microscopic counts, or other methods. Newton, 1 subsieve sizes

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Particle sizes too small for efficient grading on screens; usually minus 200-mesh material. They are examined by elutriation (beaker decantation, sedimentation, infrasizing in air, turbidimetry, permeability). Pryor, 3 subsilicate A basic silicate. subsilicic A term proposed by Clarke (1908) to replace basic. CF: persilicic; mediosilicic. AGI subslicing See: top slicing combined with ore caving subsoil drainage The removal of subsoil water by open intercepting ditches and drain pipes. The distance between subsoil drains is a maximum in sandy soils and a minimum in clay. See also: catchwater drain subsoiling The firing of small charges of dynamite 2 ft or 3 ft (0.6 m or 0.9 m) below the surface for breaking up impervious strata of soil, clay, etc., for aerating, draining, and moistening the soil. subsoil plow A one-tooth ripper designed for agricultural work. Also called pan breaker. Nichols, 1 substage a. A subdivision of a stage; the rocks formed during a subage of geologic time. AGI b. In a microscope, a mechanism for holding polarizers or other attachments below the stage. AGI substation An electrical installation containing generating or power-conversion equipment and associated electric equipment and parts, such as switchboards, switches, wiring, fuses, circuit breakers, compensators, and transformers. substitute 3166

Any substance represented to be, or used to imitate, a gemstone; e.g., plastic, glass, doublet, synthetic ruby, or natural spinel; all could be substitutes for natural ruby. AGI substitution A chemical defect wherein one ion replaces another in a crystal structure. Substitution may be partial; e.g., iron for zinc in sphalerite up to 30%, or complete; e.g., manganese and iron in the series rhodochrosite-siderite. substoping a. An open stope method of mining employed in wide orebodies with strong walls. Nelson b. See: sublevel stoping substrate a. A layer of metal underlying a coating, regardless of whether the layer is basis metal. ASM, 1 b. The true lattice of a crystal, as distinct from its discontinuity lattice, or surface. Pryor, 2 substructure a. That part of any structure that is below ground, more particularly the foundations. The latter may take many forms, according to the nature and bearing strength of the ground. Hammond b. The lower portion of a structure upon which something else is built up. Crispin subsurface a. The zone below the surface, in which geologic features, principally stratigraphic and structural, are interpreted on the basis of drill records and various kinds of geophysical evidence. AGI b. Rock and soil materials lying beneath the Earth's surface.--adj. Formed or occurring beneath a surface, esp. beneath the Earth's surface. CF: surficial c. An underground workplace. Long subsurface contour See: structure contour subsurface correlation Correlation of rock units and structures that do not appear at the surface, by means of well logs, mine maps, and geophysical data. Stokes subsurface corrosion 3167

Formation of isolated particles of corrosion products beneath the metal surface. This results from the preferential reaction of certain alloy constituents by inward diffusion of oxygen, nitrogen, and sulfur. ASM, 1 subsurface geology Geology and correlation of rock formations, structures, and other features beneath the land or sea-floor surface as revealed or inferred by exploratory drilling, underground workings, and geophysical methods. CF: surface geology subsurface injection See: subsurface waste disposal subsurface map a. A map depicting geologic data or features below the Earth's surface; esp. a plan of mine workings, or a structure-contour map of a petroleum reservoir or an underground ore deposit, coal seam, or key bed. AGI b. A plane surface representation, generally in horizontal projection, of geologic data or features beneath the Earth's surface. There are many types of subsurface maps, such as structure contour maps, isopachous maps, and maps showing variations in lithology, or proportions of different types of lithology in rocks not exposed at the surface. Stokes subsurface waste disposal Waste disposal in which manufacturing wastes are deposited in porous underground rock formations. Disposal wells should be at least 200 ft (61 m) deeper than the deepest water-bearing formation, and they must be sealed with cement from top to bottom. Also called subsurface injection. subsurface water Water in the lithosphere in solid, liquid, or gaseous form. It includes all water beneath the land surface and beneath bodies of surface water. Syn: subterranean water; underground water; ground water. AGI subtense bar A horizontal bar used in the subtense system of surveying by tacheometry. It is held at a distant point and its distance is calculated from its known length and the angle that it subtends at the observer's eye. See also: tachymeter subterrain 3168

See: subterrane subterrane The bedrock beneath a surficial deposit or below a given geologic formation. Syn: subterrain subterranean Formed or occurring beneath the Earth's surface, or situated within the Earth. CF: subaerial subterrane. AGI subterranean stream A body of subsurface water flowing through a cave or a group of communicating caves, as in a karstic region. AGI subterranean water See: ground water; subsurface water. subterrestrial See: subterranean subtranslucent See: semitranslucent subtransparent Imperfectly or partially transparent; semitransparent. Webster 3rd subvitreous Not quite vitreous. Webster 3rd subvolcanic See: hypabyssal subweathering

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Below weathering. Pertaining to the consolidated material-bedrock or high-velocity weathered layer or zone. This velocity is distinctly greater than that in the weathered zone. AGI succinite a. An old name for amber, esp. amber mined in former East Prussia (Poland) or recovered from the Baltic Sea. b. A light yellow, amber-colored variety of grossular garnet. suck The shape of the bottom of a cutting edge or tooth that tends to pull it into the ground as it is moved. Nichols, 1 sucked stone Corn. A honeycombed or porous stone. sucking pump A suction pump. Standard, 2 suction a. Atmospheric pressure pushing against a partial vacuum. Nichols, 1 b. The pull of a pump. Nichols, 1 c. Adhesion of a mass of mud to the underside of an object being lifted out of it. Nichols, 1 suction anemometer An anemometer that measures wind velocity by the degree of exhaustion caused by wind blowing through or across a tube. Standard, 2 suction bailer See: sand pump suction basket The strainer at the foot of the suction pipe of a pump or of a suction hose. Standard, 2 suction blast See: backlash 3170

suction chamber A suction chamber is designed to provide a trough of low pressure between the sealed area and the intake, so that air that would otherwise be drawn into the sealed area, through fissures and pores surrounding the seal, is drawn instead into the chamber. If the pressure within the sealed-off mine area is less than that outside, it is necessary to reduce the pressure within the chamber. This can be done by using an ejector or fan to draw air through a pipe in the outer wall of the chamber; a second pipe, fitted with a control valve, serves as an intake. Adjustment of the valve gives regulation of the chamber pressure within fine limits. Roberts, 1 suction cutter a. In dredging, use of pump fed by pipe with power-rotated cutting blades to lift spoil. Pryor, 1 b. In alluvial dredging, use of power-rotated cutting shoe to detach minerals from deposit, followed by their delivery by suction and elevation through a centrifugal pump. Pryor, 3 suction-cutter dredge A dredge in which rotary blades dislodge the material to be excavated, which is then removed by suction, as in a sand-pump dredger. CTD suction dredge a. A dredge that digs by means of powerful suction pumps, the semiliquid spoil thus raised being frequently conveyed away in a floating pipeline. Hammond b. See: sandpump dredger c. A dredge in which the material is lifted by pumping through a suction pipe. suction fan A fan that sucks or draws the air toward it through airways or air pipes. The term generally used is exhaust fan. Nelson suction head The head or height to which water can be raised on the suction side of the pump by atmospheric pressure. See also: lift pump suction lift In pump nomenclature, it exists when the liquid level is below the pump centerline and/or when a gage on the suction would show a vacuum. 3171

sudburite An augite-bearing hypersthene basalt characterized by pillow structure and containing bytownite and magnetite. It differs from normal basalts in containing neither glass nor olivine and in having an equigranular texture (Johannsen, 1937). Its name, given by Coleman in 1914, is derived from the Sudbury District, ON, Canada. Not recommended usage. AGI sugar sand A variety of sandstone that breaks up into granules resembling sugar. sugar spar Corn. Friable granular quartz. See also: sugary quartz sugar stone a. Eng. An ironstone in Norfolk, so-named from its rich brown color. Arkell b. Compact white to pink datolite from the Michigan copper district. sugar-tube method A dust-sampling technique that measures airborne dustiness on a mass basis. In the glass tube is placed a layer, 1-1/2 in (3.8 cm) deep, of sized granulated sugar weighing 100 g. By means of a suitable pump, air is drawn through the sugar tube at a rate of approx. 1 ft3 /min (0.0283 m3 /min). The dust is retained in the sugar tube, which is then stoppered and sent to the laboratory for analysis. The sugar is dissolved and the dust is caught on a filter paper that is incinerated to give the weight of dust. Greenburg sugary quartz A granular and somewhat friable and massive variety of quartz. Syn: sugar spar suite a. A set of apparently comagmatic igneous rocks. AGI b. A collection of rock specimens from a single area, generally representing related igneous rocks. AGI c. A collection of rock specimens of a single kind; e.g., granites from all over the world. AGI d. In stratigraphy, the lithodemic unit next higher in rank to lithodeme. It comprises two or more associated lithodemes of the same class (e.g., plutonic, metamorphic). For cartographic and hierarchical purposes, suite is comparable to group. The name of a suite combines a geographic term, the term suite, and an adj. denoting the fundamental character of the suite; e.g., Idaho Springs Metamorphic Suite. AGI e. A major group of Tertiary and younger igneous rocks thought by Harker (1909) to characterize regions 3172

around each of the world's great oceans. Because there is such a wide variety of tectonic environments and associated rock types in these regions, the terms are now seldom used. See also: Atlantic suite; Pacific suite; Mediterranean suite. CF: lithodeme suites (of igneous rocks) See: consanguinity sulfate-bearing soils On silts where the groundwater contains more than 0.1% of SO3 , or where a clay soil has more than 0.5% of this substance, the use of lime-free cement in all concrete work is essential to prevent the resulting chemical attack. High-alumina cement gives complete protection, but a sulfate-resisting cement to British Standard 12 may be used where conditions are less severe. Hammond sulfate sulfur The inorganic sulfur in coal other than the pyritic sulfur. BS, 1 sulfate test Sulfate in soil can be precipitated as barium sulfate and measured so as to indicate whether water or soil will have a harmful effect on concrete. Hammond sulfating roast A roast in which conditions in a furnace allow sulfur in feed to recombine with calcined products to form sulfates. Syn: sulfatizing roast Pryor, 3 sulfatizing The chemical reaction that takes place in many roasting operations in which metallic sulfates form instead of oxides. Newton, 1 sulfatizing roast See: sulfating roast sulfhydryl-collector method In flotation, a method for treatment of various oxygen ores where sulfhydryl collectors are used to float the base-metal minerals from associated minerals. Gaudin, 2 sulfide 3173

a. A mineral compound characterized by the linkage of sulfur with a metal or semimetal; e.g., galena, PbS, or pyrite, FeS2 . AGI b. A mineral with S2- or S22- as its anion. sulfide enrichment Enrichment of a deposit by replacement of one sulfide by another of high value, as pyrite by chalcocite. AGI sulfide of iron An iron ore with sulfur as its main impurity. Mersereau, 2 sulfide ore Ore in which the sulfide minerals predominate. See also: mixed ore sulfide zone a. That part of a sulfide deposit that has not been oxidized by near-surface waters. See also: oxidized zone; protore. AGI b. A generally manto-shaped deposit in which secondary sulfide enrichment has occurred as a part of ore-deposit oxidation. Syn: secondary sulfide zone sulfidization In conditioning a flotation pulp, addition of soluble alkaline sulfides in aqueous solution to produce a sulfide-metal layer on an oxidized ore surface. Pryor, 3 sulfidizing method In flotation, a method for treatment of various oxide ores in which the desired base-metal minerals are sulfidized, then the ore is floated as if it were a sulfide ore. It is useful in treating lead carbonate ores, less useful if other lead minerals are present, and of limited utility in connection with copper and zinc ores. Gaudin, 2 sulfite A salt or ester of sulfurous acid; a compound containing the radical, SO3- . AGI sulfo-antimonite A mineral in which sulfur and antimony are united chemically with a metal. Weed, 2 sulfoarsenite 3174

An ore mineral of any metal or metals with which sulfur and arsenic are united chemically. Weed, 2 sulfonic acid A hydrophilic group. In the sulfate ester, an oxygen link is provided, forming the acid group of many commercial surface-active agents in which a little sulfonic acid and much long-chain sulfate ester are linked to fatty acids and oils. Examples of reagents used in mineral processing include Lissapol LS (sodium salt of oleic acid chloride and panisidine sulfonic acid); and Aerosol (sulfosuccinic acid diester). Pryor, 3 sulfonite Light green to yellow vaselinous variety of sulfur-containing bitumen. Tomkeieff sulfophile Elements that occur preferentially in minerals free of oxygen (or fluorine or chlorine); i.e., mostly as sulfides, selenides, tellurides, arsenides, antimonides, intermetallic compounds, native elements, etc. This group includes some of the chalcophile and some of the siderophile elements as classified by Goldschmidt. AGI sulfur a. Sulfureted hydrogen, H2 S ; stinkdamp. Fay b. One of the elements present in varying quantities in most bituminous coal as part of the ash and deleterious to coke for steelmaking. BCI c. An orthorhombic mineral, 128[S] ; native sulfur; dimorphous with rosickyite; soft; yellow; around volcanic fumaroles, in salt deposits associated with limestone, gypsum, and anhydrite; a source of elemental sulfur. Also called brimstone. d. A mining term for iron sulfide (pyrite) in coal seams and with zinc ores in Wisconsin and Missouri. Formerly spelled sulphur. e. See: crude sulfur sulfur ball a. An accumulation of sulfur in the form of iron pyrites sometimes found in coal seams, often hard enough to break the bits on cutting machines. BCI b. A concretionary form of the sulfide of iron occurring as both pyrite and marcasite. This material seems to crystallize or grow within the coal as a result of the action of waters bearing sulfuric acid acting upon compounds of iron. This iron is then taken into solution as iron sulfates and subsequently converted to sulfides that form into the sulfur ball. Kentucky sulfur dome An inverted container, holding a high concentration of sulfur dioxide gas, used in die casting to cover a pot of molten magnesium to prevent burning. ASM, 1 3175

sulfuret Pac. The undecomposed metallic ores, usually sulfides. Chiefly applied to auriferous pyrites. Concentrate and sulfide are preferable. An old syn. for sulfide. Obsolete. sulfur group The group VI elements sulfur, selenium, tellurium, and oxygen. sulfur mining Thick sulfur-bearing deposits may be worked by a network of tunnels and general caving. The bed is extracted in a series of thick slices, horizontal if the dip is great, or parallel to the dip if it is moderate. See also: Frasch process sulfur ore Pyrite, often roasted for its sulfur. Webster 2nd sulfydril Mercapto thiol. -SH, the monovalent radical. Pryor, 3 sullage a. Mud and silt deposited from flowing water. Hammond b. Scoria on molten metal in the ladle. Webster 3rd Sullivan angle compressor A two-stage compressor in which the low-pressure cylinder is horizontal and the highpressure cylinder is vertical. It is a compact compressor and is driven by a belt, or it can be directly connected to an electric motor or diesel engine. Lewis sulphur See: sulfur sulvanite An isometric mineral, Cu3 VS4 ; forms a series with arsenosulvanite; bronze yellow; at Burra Burra, South Australia; and Mercur, UT. summary of reinforcement 3176

A cutting list with details of reinforcing bars. Hammond summer black oil A black lubricating oil of 540 degrees F (282 degrees C) fire test, used as a heavy tempering oil and for waterproofing cement. sump a. An excavation made underground to collect water, from which it is pumped to the surface or to another sump nearer the surface. Sumps are placed at the bottom of a shaft, near the shaft on a level, or at some interior point. Lewis b. An excavation smaller than and ahead of the regular work in driving a mine tunnel or sinking a mine shaft. Webster 3rd c. A hole sunk in a drift to a depth of 2 to 3 yd (1.8 to 2.7 m). Hess d. To undercut coal preliminary to placing a shortwall machine in position for cutting along the working face. Sometimes called a sumping cut. e. To test the load in depth. Gordon f. See: cut g. To drill diagonally. Mason h. See: jib in i. A pit or basin in which the returns from a borehole are collected and stored and in which the cuttings settle before recirculating the cuttings-free drilling fluid. Long j. A cellar under a drill floor. Long sump cleaner In bituminous coal mining, one who shovels up accumulations of coal, rock, dirt, and refuse at the bottom of a shaft and loads it into buckets that are hoisted to the surface or an upper level for dumping. DOT sumper a. A shothole drilled diagonally. Mason b. In bituminous coal mining, a person who oils and greases coal-cutting machines. Also called machine sumper. DOT sump fuse A waterproof fuse for use in a sump. Standard, 2 sumping a. Forcing the cutter bar of a coal cutter into or under the coal. Also called sumping cut. b. A small square shaft, generally made in the airheadings when crossing faults, etc., or made to prove the thickness of coal, etc. sumping bar

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An angle iron about 8 ft (2.4 m) long with flanges about 4 in (10 cm) high, weighing about 75 lb (34 kg). Its function is to guide the cutter bar on an electric coal-cutting machine. Fay sumping cut See: sump sumping-in See: jibbing-in sumpman In metal mining, a person who installs sets of timbers to support the walls of a shaft, working with the shaft sinking crew and installing the timbers as the work advances. DOT sump shaft The shaft in a mine at the bottom of which is the sump. Standard, 2 sump shot A blast made in a shaft that is being sunk, to make a collecting place for water. Standard, 2 sump winze A winze sunk in the bottom of the lowest level, to explore the lode below and ascertain whether the sinking of the main shaft is advisable. Standard, 2 sun bed a. A sublithographic limestone or mudstone at the top of the White Lias, the upper surface of which bears polygonal cracks attributed to sun drying. b. Alternatively a corruption of "sound" bed because, when dry, the rock rings when broken with a hammer. CF: guinea bed; ring stone. sun cheek The south side of a vein. Arkell sun crack 3178

See: mud crack Sunday stone A calcareous deposit formed inside pipes carrying waste water from collieries. It is composed of alternating dark and light bands corresponding to the day and night shifts and a broader light band corresponding to Sunday. Arkell Sundberg method In electrical prospecting, an inductive method in which the current flows through an insulated copper cable connected to a source of alternating current and run along the surface in a rectangle 1 mile by 1/2 mile (1.6 km by 0.8 km) in dimensions. A series of transverse profiles are laid out perpendicular to and crossing the cable, and the magnetic part of the electromagnetic field is measured at discrete points along the profiles by special search coils consisting of several hundred turns of wire. The magnitude and direction of the induced field observed by the coils can be related to the inductive effect of the subsurface material directly below. Dobrin sundiusite a. A monoclinic mineral, Pb10 (SO4 )Cl2 O8 ; forms plumose aggregates of adamantine crystals having one perfect cleavage; at Laangban, Sweden. b. A name proposed for a hypothetical amphibole end-member composition, but never accepted by the IMA nor widely used by mineralogists. sundtite See: andorite sun gear The central gear in a planetary set. Nichols, 1 sunk Drilled or excavated downward. Long sunken pit See: dig-down pit sunk shaft A shaft that is driven from the top downward (vertical or inclined). Fraenkel 3179

sun opal See: fire opal sunshine A name of a soft grade of paraffin wax with a low melting point. It can be burned in an ordinary miners' lamp with a nail (usually copper) in the wick and gives little smoke. Also called miners' sunshine. sunstone a. An aventurine feldspar, generally a brilliant, translucent variety of oligoclase that emits a reddish or golden billowy reflection from minute scales or flakes of hematite spangled throughout and arrayed parallel to planes of repeated twinning. CF: goldstone; moonstone. Syn: heliolite b. A red-to-yellow variety of bytownite caused by minute inclusions of copper and found in basalt from Oregon. See also: aventurine sun vein N. of Eng. Ore vein discovered on the south side of a hill. Sun is synonymous with south, so sun veins are south veins. super airflow cleaner In this cleaner, the coal is fed from a raw coal hopper by an oscillating plunger feeder ensuring uniform feed throughout the entire width of the machine deck. A rotating shutter in the inlet duct provides a pulsating air current, which is much more effective as a separating current than a uniform airstream. The coal and refuse stratify as they move toward the discharge end of the deck with the refuse falling to the bottom against the deck. The perforated deck has four refuse draws; normally the products of the first two draws are discharged as refuse and the third and fourth draws as middlings. The product of the third draw may be refuse or middlings, depending on the ash content of the feed. Generally, this cleaner is an effective machine for cleaning coal from 3/4 in (1.91 cm) to 1/4 in (0.64 cm) by 28 mesh if it contains less than 5% of surface moisture. It will not clean effectively below 20 mesh. Kentucky superalloy An alloy for very high-temperature service in which relatively high stresses (tensile, vibratory, and shock) are encountered and oxidation resistance is frequently required. ASM, 1 supercapacity bucket elevator 3180

A type of continuous bucket elevator employing supercapacity elevator buckets. See also: supercapacity elevator bucket supercapacity elevator bucket A type of continuous elevator bucket used with a pair of chains in which the back of the bucket at the bottom extends backward into space between the up and down runs to provide additional capacity without increase in length or projection. See also: supercapacity bucket elevator supercharger A blower that increases the intake pressure of an engine. Nichols, 1 superconductivity The abrupt and large increase in electrical conductivity exhibited by some materials at very low temperatures. ASM, 1 supercritical area of extraction An area of goaf of sufficient extent to cause full subsidence at more than one point on the surface. Nelson superdip An instrument of limited sensitivity for measuring changes in the total intensity of the magnetic field. Schieferdecker superdusting The presence of a very large excess of coal dust in the air over that required for consumption of the oxygen. Rice, 2 superexchange The antiparallel alignment of unpaired d electrons of metal cations through coupling with p electrons of intervening anions to produce magnetic order. CF: ferrimagnetism; antiferromagnetism. superficial Pertaining to, or lying on or in, a surface or surface layer; e.g., superficial weathering of a rock, or a superficial structure formed in a sediment by surface creep. The term is used 3181

esp. in Great Britain; the syn. surficial is more generally applied in the United States. AGI superficial compaction Compaction of soil in layers generally not greater than 6 in (15 cm) deep, by various methods, including the use of the frog rammer, vibration, sheepsfoot roller, pneumatic tired rollers, or similar machines. See also: compaction equipment superficial deposit The most recent of geological formations; unconsolidated detrital material lying on or near the surface, generally unstratified. See: surface deposit supergene Said of a mineral deposit or enrichment formed near the surface, commonly by descending solutions; also, said of those solutions and of that environment. CF: hypogene; mesogene. AGI supergene enrichment A mineral deposition process in which near-surface oxidation produces acidic solutions that leach metals, carry them downward, and reprecipitate them, thus enriching sulfide minerals already present. Syn: enrichment; secondary enrichment. See also: oxidized zone superheated steam Steam above a temperature of 100 degrees C; produced by heating water under a pressure greater than standard atmosphere. Nelson superheater a. A device that superheats, esp. steam or other gases; esp. a coil or other device through which steam from a boiler passes to be superheated. Webster 3rd b. A refractory lined chamber in a water-gas plant that ensures completion of the decomposition of the oil vapors begun in the carburetor. Dodd superimpose In geology, to establish (a structural system) over, independently of, and eventually upon underlying structures; said of terranes, rivers, drainage systems, valleys, etc.; as, a superimposed valley. Standard, 2 3182

superimposed halo A dispersion pattern formed in the regolith by the movement of material in subsurface waters. Hawkes, 1 superintendent-of-tanks One who supervises the feeding and maintenance of glass-melting furnaces (tanks), and the operation of reheating ovens (lehrs) for fire-glazing glass articles. Directs unloading and storage of raw materials and crushing and washing of waste glass (cullet) used as ingredients in the manufacture of new glass. DOT superjacent pattern A dispersion pattern developed more or less directly over the bedrock source. Hawkes, 2 superjacent roadway system See: methane drainage superlattice X-ray diffractions, in addition to fundamental diffractions, which appear as an alloy inverts from disorder to perfect order of its constituent atoms at lattice sites; called superlattice diffractions and attributed to a superstructure of ordered atoms. Superlattice diffractions also appear where long-range order obtains in the stacking of silicate structural units, such as in phyllosilicates. See: superstructure; long-range order. superpanner A mechanism that simulates rocking, bumping, and sluicing action used in panning and gives precise information as to the possibility of gravity treatment of sands. It is used in rapid assays and as a research aid. Pryor, 2 superphosphate Any of various commercial phosphate fertilizers obtained as white to gray granules or powders by acidulating ground insoluble phosphate rock, such as: (1) a product made by acidulating with sulfuric acid, consisting essentially of primary calcium phosphate, calcium sulfate, and smaller quantities of secondary calcium phosphate, and containing usually about 20% of available phosphoric acid; or (2) a product made by acidulating with phosphoric acid, consisting essentially of primary calcium phosphate and containing usually 40% to 50% of available phosphoric acid. Webster 3rd superposition 3183

a. A principle stating that if a body is subjected to several stresses acting simultaneously, then each stress produces its own strain or strains, and these strains may be superimposed to give the complete state of strain of the solid. Similarly, two separate stress distributions in a body, due to the application of two separate stresses, may be superimposed to give the stress distribution due to the simultaneous application of these two stresses. Issacson b. The order in which rocks are placed or accumulated in beds one above the other, the highest bed being the youngest. AGI superprint See: overprint superpushing Using extra large pushers, or two or even three standard units in tandem, to increase the speed and size of loading. Nichols, 1 supersaturated solution A solution that contains more of the solute than is normally present when equilibrium is established between the saturated solution and undissolved solute. AGI super section Two sets of mining equipment operating simultaneously and sharing a common dumping point on the same section, with each set being ventilated by a separate split on intake air. FR 95 superstructure A crystal structure resulting from large unit cells when an alloy inverts from disordered occupancy of lattice sites by "averaged" constituent atoms in small unit cells to individual atomic species occupying specific lattice sites and having long-range order; e.g., disordered Cu3 Au has a primitive cubic unit cell with averaged "Cu-Au atoms" at each corner, while ordered Cu3 Au has a face-centered cell with Au atoms its corners and Cu its face centers, the large face-centered unit cell containing eight of the small primitive unit cells. See: superlattice; long-range order. supplementary twinning Twinning by which a crystal simulates the symmetry of a crystal class with higher grade in the same system. supplied-air respirator 3184

An atmosphere-supplying device that provides the wearer with respirable air from a source that is outside of the contaminated area. Best, 1 supply cager In anthracite and bituminous coal mining, one who directs and assists the loading of mine supplies on a cage (elevator) at a mine having a separate shaft or shaft compartment for handling supplies. DOT supply-hoist engineer See: supply-hoist operator supply-hoist operator In anthracite and bituminous coal mining, one who operates the hoisting machinery that serves the shaft or shaft compartment of a mine in which mining supplies are lowered into the mine. Also called supply-hoist engineer. DOT supply motorman In bituminous coal mining, a person who operates a mine locomotive to haul trips (trains) of cars, loaded with timbers, rails, explosives, and other supplies, into a mine. DOT supply pump See: bank pump support A general term for any timber, steel, concrete, brick, or stone structure erected to counteract the subsidence of the roof strata when undermined. See also: self-advancing supports; steel arch; steel support. Nelson support roller In a crawler machine, a roller that supports the slack upper part of the track. Nichols, 1 supports Materials placed in stopes for the purpose of ground control, that is to arrest or regulate the closure of the walls. Spalding suppressed weir 3185

A measuring weir having its sides flush with the sides of the channel, so that there are no end contractions. Hammond supratenuous fold A pattern of fold in which there is thickening at the synclinal troughs and thinning at the anticlinal crests. It is formed by differential compaction on an uneven basement surface. CF: similar fold; parallel fold. AGI surcharge a. Any load including earth that is supported above the level of the top of a retaining wall. See also: relieving platform; active earth pressure. Hammond b. The algebraic sum of the losses and gains of a cornet of gold during cupellation and solution. Fay surface a. The top of the ground. As used in the conveyance of coal in place, or in a conveyance of land reserving the minerals, includes not merely the surface within the boundary lines, without thickness, but includes whatever earth, soil, or land lies above the superincumbent upon the coal or mineral reserved. b. See: cover; drift; mantle; overburden. c. In geology, usually refers to (1) the boundary surface between one bed or mass of rock and another immediately adjacent, such as a bedding surface, a fault surface, a surface of unconformity, a surface of igneous compact, or (2) an imaginary surface, such as the axial surface of a fold. Challinor surface action Any kind of action that affects a surface; e.g., action of smoke fumes, moisture, etc., on a painted surface. Crispin surface-active agent Chemical compound that modifies physical, electrical, or chemical characteristics of surface of solid, also surface tensions of solids or liquids. Used in froth flotation and in detergency. Characteristically, its heteropolar molecules are attracted to a specific type of surface in a mixture where one group forms polar monolayer attachments while the rest of the molecule points outward and changes the relations between the surface and the ambient phase. These relations may change lyophilic and aerophilic attraction, surface tension, intermiscellar grouping, emulsification, and froth foaming. Surfaceactive agents include cleaners (e.g., soaps); water repellants (e.g., greases); dispersants and emulsifiers (e.g., glue); and additives adsorbed at interfaces between liquids (usually aqueous) and external gas, liquid or solid phases, with resulting change in interfacial tension. Three electrochemical types are unionized molecule, anion, and cation. Important characteristics of surface-active agents are solubility in the medium 3186

and effects of specific adsorption at interfaces. Such agents either provide anchorage between phases or form a barrier, according to their flocculating or dispersing effect. Pryor, 3 surface activity The property possessed by certain solid substances to influence the surface tension of liquids. See also: depressant; flotation agent; surface tension. Hammond surface air leakage The amount of surface air entering a fan through the casing at the top of the upcast shaft, the airlock doors, and the fan-drift walls. The extent of leakage will depend on the fandrift water-gage method of construction, the number and type of entrances, and whether the upcast shaft is used for winding. The surface leakage at airlocks may vary from about 25,000 ft 3 /min (708 m3 /min) at 5-in (12.7-cm) water gage to about 55,000 ft3 /min (1,557 m3 /min) at 25-in (63.5-cm) fan-drift water gage. See also: volumetric efficiency surface area Of a particle, area calculated from data obtained by a specified method, such as: (1) adsorption measurement, (2) calculation, (3) permeability measurement, (4) microscopic observation, or (5) close screening and averaging from study of a number of particles. Pryor, 3 surface break See: surface damage surface bunker A large capacity hopper or standage room to store coal or mineral coming from the winding shaft. The provision tends to equalize the run of mine going to the preparation plant and smooth out any minor breakdowns in the plant. Nelson surface charges All expenses incurred on the surface of a mine that have to be charged against the mineral. surface circuit The mine car track layout from the shaft to the preparation plant and back to the shaft. The term includes all the equipment necessary to move and control the movement of cars, such as creepers, retarders, back shunts, traversers, and turntables. Nelson 3187

surface clay An unconsolidated, unstratified clay occurring on the surface. ASTM surface conductance The heat transmitted from (or to) a surface to (or from) the fluid in contact with the surface in a unit of time per unit of surface area per degree temperature difference between the surface and fluid. Measured in units of watts per square meter Kelvin. Strock, 2 surface damage a. Any damage done to land surface during mine exploration or development operations. Syn: surface break b. Scot. Ground occupied and damaged by colliery operations; the compensation for such. surface deposit a. Orebody that is exposed and can be mined from the surface. Zern b. See: superficial deposit surface dressing The covering of an existing surface with a coating of bituminous binder covered by a layer of chippings or fine aggregate. Nelson surface drift A drift (usually inclined) from the surface to the coal seam or orebody to be developed. See also: drift mining; slant. Nelson surface drilling Boreholes collared at the surface of the Earth, as opposed to holes collared in mine workings or underwater. See also: surface rig Long surface energy Product of surface tension (dynes per centimeter) and surface area (centimeters), expressed in ergs. Work required to increase surface area by unit area. Pryor, 3 surface factor See: fineness factor 3188

surface geology a. Geology and correlation of rock formations, structures, and other features as seen at the Earth's surface. CF: subsurface geology AGI b. See: surficial geology surface leaching A mining practice that represents an alternative to conventional ore beneficiation in that the mineral values are hydrometallurgically extracted rather than concentrated in solid form for further processing. See also: solution mining surface lift A term used in the freezing method of shaft sinking. The surface around the shaft tends to heave owing to the formation of ice and the variation of temperatures. This uplift is sufficient to throw surface structures, such as winding towers, out of alignment. To enable corrections to be made, the tower bases may be mounted on grillages with facilities for jacking to keep the towers level. Nelson surface lines The boundary lines of a mining claim as indicated by the locator. surface loss Losses of air occurring in the restricted area around the tub and caused by the increased velocity along the walls of the airway, and from the friction and turbulent effects due to the surfaces of the tub. For an empty tub, a portion of the turbulent effect is due to eddying and shock within the tub. Roberts, 1 surface mining a. The mining in surface excavations. It includes placer mining, mining in open gloryhole or milling pits, mining and removing ore from opencuts by hand or with mechanical excavating and transportation equipment, and the removal of capping or overburden to uncover the ores. b. Mining at or near the surface. This type of mining is generally done where the overburden can be removed without too much expense. Kentucky c. The obtaining of coal from the outcroppings or by the removal of overburden from a seam of coal, as opposed to underground mining; or any mining at or near the surface. Also called strip mining; placer mining, opencast; opencut mining; open-pit mining. BCI; Standard, 2 surface plan A map of the surface layout of a mine. BS, 7 3189

surface reinstatement The restoration of the surface after opencast mining operations have been completed. The work may involve leveling the hill-and-dale formation, drainage, and relaying of the original topsoil, also known as resoiling. Nelson surface rig A drill rig designed specif. and used only for surface drilling operations. See also: surface drilling surface rights a. The ownership of the surface of land only where mineral rights are reserved. Weed, 2 b. The right of a mineral owner or an oil and gas lessee to use so much of the surface of land as may be reasonably necessary for the conduct of operations under the lease. Williams c. Those reserved to the owner of the land beneath which ore is being mined. Pryor, 3 surface-set bit A bit containing a single layer of diamonds set so that the diamonds protrude on the surface of the crown. Also called single-layer bit. CF: multilayer bit surface slope The inclination of the water surface expressed as change of elevation per unit of slope length; the sine of the angle that the water surface makes with the horizontal. The tangent of that angle is ordinarily used; no appreciable error resulting except for the steeper slopes. Seelye, 1 surface speed See: peripheral speed surface string A large diameter drivepipe sunk through the uppermost part of the overburden. CF: conductor; standpipe. Long surface tension a. In the flotation process, the contractile force at the surface of a liquid whereby resistance is offered to rupture. b. Interfacial tension between two phases, one of which is a gas. ASM, 1 c. A condition that exists at the free surface of a body (such as a liquid) 3190

by reason of intermolecular forces unsymmetrically disposed about the individual surface molecules and is manifested by properties resembling those of an elastic skin under tension. Specif., the force per unit length of any straight line on the surface that the surface layers on opposite sides of the line exert upon each other. See also: surface activity surface texture The aggregate of the surface features of sedimentary particles, independent of size, shape, or roundness; e.g., polish, frosting, or striations. AGI surface thrust See: erosion thrust surface water Water that rests on the surface of the lithosphere. AGI surface-water drain Any pipe laid in the ground for carrying away surface water. See also: separate system surface wave An elastic wave in which the energy is confined to the surface or a narrow region just below the free surface of an extended solid. These waves readily follow the curvature of the part being inspected and are reflected only from sharp changes of direction at the surface. ASM, 1 surface working See: surface mining surfactant Surface active agent, a substance that affects the properties of the surface of a liquid or solid by concentrating in the surface layer. Brantly, 1 surfeit Gr. Brit. Afterdamp or chokedamp; or pressure exercised by a pent-up gas resulting in its escape with or without rupture of strata. Tomkeieff surficial 3191

Pertaining to, or occurring on, a surface, esp. the surface of the Earth. CF: subsurface surficial creep See: soil creep surficial geology Geology of surficial deposits, including soils; the term is sometimes applied to the study of bedrock at or near the Earth's surface. See also: surface geology surf zone The area between the outermost breaker and the limit of wave uprush. Syn: breaker zone surge a. To move sideways; to fleet. Mason b. The uneven rate of flow and regular variations in pressure caused by time lags between pressure strokes on a piston-type pump. Long c. In fluid flow, long-interval variations in velocity and pressure that are not necessarily periodic and may even be transient. AGI surge bin a. In salt mining, a generally large bin above the crusher into which the mine-run salt is dumped prior to being discharged into the primary crusher. A feeder at the bottom of the surge bin facilitates transfer of the mine-run material to the crusher. Kaufmann b. A compartment for temporary storage, which will allow converting a variable rate of supply into a steady flow of the same average amount. Nichols, 1 surge bunker A large-capacity storage hopper, installed near the pit bottom or at the input end of a processing plant to provide uniform feeding of material from bulk deliveries. Surge bunkers are generally required either on the surface or underground to act as a buffer between the shaft and the coal preparation plant and the working faces. See also: bunker; surge hopper. Nelson; Sinclair, 5 surge hopper A hopper (bunker) designed to receive a feed at fluctuating rate and to deliver it at some predetermined rate. Syn: surge bunker surge pipe 3192

Open-topped standpipe to release pressure from surge. Hammond surge pulley The pulley used on a tension carriage in endless-rope haulage. See also: balanced directrope haulage surge tank a. A standpipe or storage reservoir at the downstream end of a closed aqueduct or feeder pipe, as for a water wheel, to absorb sudden rises of pressure and to furnish water quickly during a drop in pressure. Webster 3rd b. An open tank to which the top of a surge pipe is connected so as to avoid loss of water during a pressure surge. Hammond c. In pumping of ore pulps, a relatively small tank that maintains a steady loading of the pump. When new pulp is in short supply, a float valve causes recirculation of part of the load, therefore avoiding settlement. Alternatively, a float may vary the speed of the pump, vary the rate of delivery to the tank, or divert the flow to a parallel system. Pryor, 3 surging The flapping of a moving rope. See: whipping surturbrand An Icelandic term for a peatlike variety of brown coal or lignite occurring in the Pliocene deposits and sometimes under the volcanic overflows of Iceland. survey a. The orderly and exacting process of examining and delineating the physical or chemical characteristics of the Earth's surface, subsurface, or internal constitution by topographic, geologic, geophysical, or geochemical measurements; esp. the act or operation of making detailed measurements for determining the relative positions of points on or beneath the Earth's surface. AGI b. The associated data or results obtained in a survey; a map or description of an area obtained by surveying. AGI c. An organization engaged in making surveys; e.g., a government agency such as the U.S. Geological Survey. d. See: borehole survey e. To determine and delineate the form, extent, and position of (as a tract of land, a coast, or a harbor) by taking linear and angular measurements and by applying the principles of geometry and trigonometry. Webster 3rd f. A measured plan and description of a portion of an area or of a road or line through an area obtained by surveying. Webster 3rd g. The information plotted from a borehole survey. Long surveying 3193

a. The act or process of making a borehole survey. See also: borehole survey b. Specif., in civil engineering, the science or art of making such measurements as are necessary to determine the relative position of points on or beneath the surface of the Earth, or to establish such points. Seelye, 2 c. The art of making a survey; specif. the applied science that teaches the art of making such measurements as are necessary to determine the area of any part of the Earth's surface, the lengths and directions of the boundary lines, and the contour of the surface, and of accurately delineating the whole on paper. AGI d. The act of making a survey; the occupation of a person that surveys. AGI survey meter An instrument sensitive to ionizing radiations used in prospecting for radioactive deposits. Webster 3rd surveyor One who applies special knowledge and techniques gained through experience or training to make surface and underground surveys at a mine, locating himself/herself on the Earth's surface by taking instrument shots on the sun or stars and making necessary calculations, surveying and calculating the volume of material in dumps, carrying survey lines underground by shaft plumbing (cord or wire with attached bob is suspended from the shaft surface) and instrument shots taken on the bob at a shaft station, controlling by underground surveys and calculations the driving and connection of underground passages on and between various levels, computing the volume of coal in portions of the mine from survey notes, and drafting maps of the mine workings. Also called spud setter; underground surveyor. Syn: mine surveyor surveyor's compass An instrument used in surveying for measuring horizontal angles. Syn: surveyor's dial Webster 3rd surveyor's cross A simple instrument made of two bars forming a right-angled cross with sights at each end and used in setting out right angles in surveying. Webster 3rd surveyor's dial See: surveyor's compass surveyor's level

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A leveling instrument consisting of a telescope (with cross hairs) and a spirit level mounted on a tripod, revolving on a vertical axis, and having leveling screws that are used to adjust the instrument to the horizontal. AGI surveyor's measure A system of measurement used in land surveying, having the surveyor's chain (one chain = 4 rods = 66 ft = 20.1 m = 100 links = 1/80 mile) as a unit. CF: Gunter's chain Surwell clinograph Well-surveying device for large-diameter holes that determines the departure of the borehole from vertical. Uses a gyroscope and spherical level with a photographic record made on 16-mm moving-picture film, which includes a photograph of a small watch by which the depth is determined from correlation with a synchronized depth-time record made at surface. AGI susannite A trigonal mineral, Pb4 (SO4 )(CO3 )2 (OH)2 ; trimorphous with leadhillite and macphersonite; in the Susanna Mine, Leadhills, Scotland. susceptibility a. Property of a material that defines the extent to which it will be magnetized in a given external field. Schieferdecker b. The ratio of the electric polarization to the electric intensity in a polarized dielectric. The ratio of induced magnetization to the strength H of the magnetic field causing the magnetization. Syn: magnetic susceptibility; volume susceptibility. AGI suspect terrane A terrane whose spatial and genetic relations with respect to adjacent terranes during their time of formation is unknown or uncertain. Inasmuch as most terranes fall into these categories, the term may be considered redundant. See also terrane. AGI suspended matter Particles from the feed, of specific gravity equal or close to that of a separating medium, and which are therefore relatively difficult to remove from the bath. BS, 5 suspended solids Solids that can be separated from a liquid by filtration. Bennett 3195

suspended tray conveyor A vertical conveyor having one or more endless chains with suitable pendant trays, cars, or carriers that receive objects at one elevation and deliver them to another elevation. Syn: corner-fastened tray conveyor; corner-hung tray conveyor; suspended tray elevator; suspended tray lift. suspended tray elevator See: suspended tray conveyor suspended tray lift See: suspended tray conveyor suspended tubbing A permanent method of lining a circular shaft in which the tubbing (German type) is temporarily suspended from the next wedging curb above. Slurry is run in behind the tubbing by means of a funnel passing through the holes provided in the segments. No temporary supports are required. See also: tubbing suspended water See: vadose water suspension a. The condition of a mixture of solid particles and water or air in which the solid particles are individually supported, normally by means of an upwardly moving current and sometimes with the assistance of mechanical agitation. BS, 5 b. A mode of sediment transport in which the upward currents in eddies of turbulent flow are capable of supporting the weight of sediment particles and keeping them indefinitely held in the surrounding fluid (such as silt in water or dust in air). AGI c. The state of a substance in such a mode of transport; also, the substance itself. AGI d. A method of rock bolting employed to secure loose fragments or sections of rock that may fall from a mine roof. Lewis; Fraenkel suspension current See: turbidity current suspension dryer See: flash coal dryer 3196

suspensoid particles Small solid particles suspended in a liquid; they exhibit the Brownian movement and do not settle by themselves, but can be readily coagulated. Bennett suspent Material in suspension that is to be filtered out. Bennett sussexite A white mineral: (Mn,Mg)BO2 (OH). It is isomorphous with szaibelyite. AGI Sutton, Steele, and Steele dry table A concentrator of the Wilfley type in motion, but instead of using water, stratification is by means of rising currents of air. Heavy grains are pushed forward by the head motion, while lighter grains roll or flow down the slope toward the tailing side. Liddell suture joint See: stylolite svabite A hexagonal mineral, Ca5 (AsO4 )3 F ; apatite group. svanbergite A trigonal mineral, SrAl3 (PO4 )(SO4 )(OH)6 ; beudantite group; at Wermland and Skane, Sweden. svitalskite See: celadonite swab a. A pistonlike device provided with a rubber cap ring that is used to clean out debris inside a borehole or casing. Long b. See: bailer; sand pump. c. In well drilling, to pull the drill string so rapidly that the drill mud is sucked up and overflows the collar of the borehole, thus leaving an undesirably empty borehole. Long d. Procedure for applying suction within the casing or tubing to draw fluid from a reservoir rock. Wheeler, R.R. e. A rod with flexible rubber suction cups working inside the pipe on a wire line. Wheeler, 3197

R.R. f. A hemp brush used in founding, esp. for holding water, moistening mold joints, spraying on edges, or spreading blacking on dry-sand molds. Webster 3rd swad a. Newc. A thin layer of stone or refuse coal at the bottom of the seam. b. N. of Eng. Impure shaly coal or black shale. Arkell swag a. A shallow, water-filled hollow produced by subsidence, resulting from underground mining. AGI b. A digger's roll of blankets, containing spare clothes, food, etc. Gordon swage block A large rectangular block of cast iron used by a blacksmith. It is pierced through with numerous holes, both round and square in section, for the reception of work that requires shouldering. Crispin swallet hole See: sinkhole swallow Derb. A loose, broken, or porous place in a vein. It derives its name from the ease with which water sinks through the loose material. swamp As applied to a mining claim, to clear a narrow strip along the boundary line, where the location is on timberland. swamp buggy Any vehicle with very large, low-pressure tires enabling it to be used in swamps. swamp ore See: bog iron; bog iron ore. swarf a. In diamond grinding operations, a relatively dry dust derived either from grinding operations where no coolant or lubricant is applied to the grinding operation or where the 3198

coolant (kerosene, an aqueous solution, or an emulsion of oil and water) is sprayed on the wheel as a fine mist. Chandler b. Fine metallic particles removed by a cutting or grinding tool; chippings and shavings from soft iron castings used as a reducing agent in various chemical syntheses. Webster 3rd c. Scot. A tool for widening boreholes. Fay d. An intimate mixture of grinding chips and fine particles of abrasive and bond resulting from a grinding operation. ASM, 1 swarm See: dike swarm swartzite A monoclinic mineral, CaMg(UO2 )(CO3 )3 .12H2 O ; radioactive; green; forms an efflorescence with gypsum, schroeckingerite, bayleyite, and andersonite. swaugh Derb. A soft clay in the vein. S wave A body wave that travels through the interior of an elastic medium with particle motion perpendicular to the direction of propagation. Originally applied to earthquake seismology, where it was the second (hence: S) type of wave to arrive at a recording station. Syn: distortional wave; equivolumnar wave; rotational wave; secondary wave; shear wave. See also: transverse wave sway A sideways movement, such as sidesway, in a structural frame. Hammond swaying of a bank York. Undergoing disturbance due to weight of the roof. A settling of the mine roof. sway rod A diagonal brace designed to resist wind or other horizontal force acting on a structural framework. Hammond sweal

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a. Eng. To burn slowly. b. To melt and run down; to waste away without feeding the flame. A candle is said to sweal when the grease runs down owing to its burning in a strong current of air or being improperly carried or fixed. sweat a. To gather surface moisture in beads as a result of condensation. The roof of a mine is said to sweat when drops of water are formed upon it, by condensation of steam formed by the heating of the waste or goaf. Webster 3rd b. To exude nitroglycerin; said of dynamite in which nitroglycerin separates from its adsorbent. Webster 3rd sweaters See: thawing sweating a. The condensation of moisture and distillation products on the surface of a roast heap, forming a damp and sticky crust. Fay b. See: exudation sweating out Bringing small globules of one of the low-melting constituents of an alloy to the surface during heat treatment, such as lead out of bronze. ASM, 1 swedenborgite A hexagonal mineral, NaBe4 SbO7 ; at Laangban, Sweden. Swedish bit See: chisel bit Swedish iron An iron of highest quality owing to the freedom from phosporus and sulfur of the Swedish ore. Crispin Swedish mining compass A compass in which a magnetic needle is suspended on a jewel and a stirrup so that it can rotate about both a horizontal and a vertical axis. AGI sweep 3200

a. Aust. That part of a branch that reunites with the main vein farther on. b. In founding, a profile pattern, used esp. in forming molds for cylindrical or other symmetrical articles. Standard, 2 c. A form or template used for shaping sand molds or cores by hand. ASM, 1 d. A curved metal blade projecting from the central shaft of a pug mill to force clay through holes at the bottom. Standard, 2 sweeping See: sweeps sweeping table Stationary circular buddle provided with rotating brushes that prevent formation of channels as pulp flows radially across. Pryor, 3 sweep plates Eng. Curved plates for barrowways at a turn. A turnsheet. sweeps a. The dust of the workshops of jewelers, goldsmiths, silversmiths, and assayers and refiners of gold and silver. Also called sweeping. b. Brushwood arms on round buddles that rotate slowly and break down channels as ore slime runs across the surface. Pryor, 3 sweepwashings Valuable metal washed from sweeps. Standard, 2 sweet a. Eng. Free from combustible gases or other gases, or from fire stink. b. Applied to potable water and to oil and gas free of hydrogen sulfide. c. Said of crude oil or natural gas that contains few or no sulfur compounds. CF: sour sweetish astringent Applied to those minerals that have the taste of alum. sweet roast See: dead roast sweet roasting 3201

Complete roasting or until arsenic and sulfur fumes cease to form. See also: roasting sweet water See: fresh water swell a. A space in a seam from which the coal has been eroded and its place filled with clay or sand. Syn: horseback b. A local enlargement or thickening in a vein or ore deposit, as opposed to a pinch. c. The tendency of soils, on being removed from their natural, compacted beds, to increase in volume owing to an increase in void ratio; i.e., the space between soil particle increases. Carson, 1 d. A low dome or quaquaversal anticline of considerable areal extent. e. Waves caused by the wind but no longer being activated. Schieferdecker f. Long and generally symmetrical waves, period approx. 10 s, produced by storm and wind remote from the point of observation. These are gravity waves and contribute to the mixing processes in the surface layer and thus to its sound transmission properties. Hy g. In geology, a large-scale submarine topographic feature rising above the surrounding surface and having nearly equal length and width. Hy swelled coupling A rod coupling having a considerably larger outside diameter than the drill rods to which it is threaded, such as BW rod outside diameter with AW rod threads. Syn: oversize coupling swelled ground a. A soil or rock that expands when wetted. Long b. Soil or rock that flows into mine workings as a result of pressure. swelling number A numerical expression to indicate the relative swelling properties of a sample when heated under standardized conditions. Nelson swelling of shale When a shaft is sunk through a thick, dry deposit of shale, the absorption of water may cause the shale to swell and damage the shaft lining. Again, when shale is exposed to weathering, the lamina tends to separate and the material swells. When wet, the disintegrated mass still further swells and eventually becomes a plastic clayey deposit. Nelson swelling pressure 3202

a. The pressure that heated and softened coal exerts when it is obstructed from free swelling. b. The pressure exerted by a contained clay when absorbing water in a confined space. swilley A depression in a mine road from which the road rises both ways. Mason swimming stone See: floatstone swinestone a. A variety of marble that gives off a fetid odor when broken or rubbed. Also called stinkstone. See also: bituminous limestone b. See: fetid calcite c. See: anthraconite swing a. In power-shovel nomenclature, the rotation of the superstructure on the vertical shaft in the mounting. Carson, 1 b. In revolving shovels, to rotate the shovel on its base. Nichols, 1 c. See: swing radius d. In churn drills, to operate a string of tools. Nichols, 1 swing angle The distance in degrees that a shovel must swing between digging and dumping points. Nichols, 2 swing cut See: slabbing cut swing-hammer crusher a. A rock breaker in which crushing force is generated by hammers loosely mounted on a rapidly revolving shaft. Rock entering the crushing chamber is hit and rebounds against liner plates of walls or against other rock, until small enough to escape through a grid. Pryor, 3 b. A machine in which size reduction is effected by elements loosely pivoted to disks fitted on a rotating horizontal shaft mounted in a surrounding casing. Also called pulverizer; swing-hammer mill; swing hammer. See also: Jeffrey crusher swing-hammer regulator

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A simple method of regulating the flow of lump ore in a chute. It consists of several heavy pivoted hammers that allow fine ore to pass through, but check the passage of lumps. Nelson swinging a claim The adjustment of the boundaries of a mining claim to more nearly conform to the strike of the vein. A reasonable time is allowed the discoverer to explore the vein or lode to find out its strike and make the adjustment. swinging-electrode controller This controller is made up of three fixed electrodes consisting of groups of parallel plates of noncorroding alloy fixed at the bottom of curved troughs of insulating material of uniform width and varying depth. The trough is deep at the end, corresponding to full speed and minimum resistance; it is shallow at the maximum-resistance starting position. The moving electrodes, of similar construction, are joined to form the star point of the rotor and are moved toward or away from the fixed electrodes, giving a wide range of resistance. Sinclair, 5 swinging-gate anemometer An instrument of the steady deflection type where speed is read off directly from the scale of the instrument. This is most useful for measuring low speeds, since it permits a spot reading. This instrument does not integrate and is used extensively in work connected with the ventilation of building interiors and to a fair extent underground. Roberts, 1 swinging plate An amalgamated copper plate hung in a sluice to catch float gold. Fay swinging-vane anemometer This instrument consists essentially of a damped, pivoted vane that is deflected when placed in an airstream. As the weight of the vane is constant, the angle of inclination will be dependent upon the rate of change of momentum of the impinging airstream. The instrument gives a direct reading and can be calibrated for use over a wide range of velocities, from 20 to 2,000 ft/min (6.1 to 609.6 m/min). In underground airways, it can be used without attachments. Its main use is the measurement of air velocity in ducts and the rate of air discharge from ventilating grills. Roberts, 1 swing-jib crane

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A crane with one horizontal boom on which there is a counterweight. It can swing through a full circle. See also: tower crane swing loader A tractor loader that digs in front and can swing the bucket to dump to the side of the tractor. Nichols, 1 swing loose Arkansas. To gradually loosen over a considerable area and sag; said of the rock over a mine working. swing of a lathe The largest diameter of work that can be carried between the centers of a lathe. In England, the swing refers to radius. Crispin swing parting Arkansas. A parting some distance from the mouth of an entry. The loaded cars are left by the gathering driver to be taken out by a swing driver. swing radius See: swing swing roller In a revolving shovel, one of several tapered wheels that roll on a circular turntable and support the upper works. Nichols, 1 swing shift a. Workday from 4 p.m. to midnight. Nichols, 1 b. Occasionally refers to the 12 midnight to 8 a.m. shift. Nichols, 1 c. Working arrangement in a three-shift continuously run plant that changes working hours at regular intervals. During swing the old morning shift becomes the new afternoon shift. The afternoon shift of the first period must work the morning shift of the next with only an 8-h break on the first day of change. Pryor, 3 Swiss lapis A fraudulent imitation of lapis lazuli (lazurite) obtained by staining pale-colored jasper or ironstone with ferrocyanide. Also known as German lapis. See also: false lapis 3205

switch a. A mine switch is a device for enabling a car or a trip of cars to pass from one track to another. The term switch is also frequently used in a loose sense to apply to the whole side track or turnout, and a car standing on a side track is frequently said to be standing on the switch. See also latches. Kiser b. Eng. A mechanical device for opening and closing an electric circuit; a mechanism for shifting a moving body in another direction. CTD switchback a. A zigzag arrangement of a roadway (or rail tracks) for surmounting the grade of a steep hill or the slope wall of a surface or open-pit mine. Common in mountainous mining districts. b. A hairpin curve. Nichols, 1 c. See: shunt back switchgear This is a general term applied to switching, interrupting, controlling, metering, protective, and regulating devices, as well as assemblies of these devices with associated interconnections, accessories, and supporting structures. The term is used primarily in connection with generation, transmission, distribution, and conversion of electric power. switch plate An iron plate on tramroads in mines used to change the direction of movement. Syn: turnsheet switch point A movable tongue or rail for diverting a train from one track to another. switch throw a. The arrangement of levers by means of which a switch is thrown for the straight track or the turnout. Jones, 1 b. The handle or lever by which a switch is operated. swither A colloquial term used in the Wisconsin lead-mining region for an offshoot or branch of a main lode. AGI swivel coupling a. A coupling where one link is made so that it can be rotated independently of other links. When such a coupling is used, one or more cars can be rotated on a revolving 3206

dump without uncoupling from the rest of the trip. Zern b. A coupling that gives complete rotary freedom to a deflecting wedge-setting assembly in boreholes. Long swivel head a. The assembly of a spindle, chuck, feed nut, and feed gears on a diamond-drill machine that surrounds, rotates, and advances the drill rods and drilling stem. On a hydraulic-feed drill, the feed gears are replaced by a hydraulically actuated piston assembly. Also called boring head; drill head; drilling head; gate. Long b. In a diamond drill, the mechanism that rotates the kelly and drill string. Nichols, 1 swivel-head bevel gear The bevel gear mounted on the outside of the drive quill in the swivel head of hydraulicfeed and/or some types of gear-feed diamond drills. The gear meshes with, and is driven by, a matching gear on the drill-motor shaft. Long swivel hoisting plug See: hoisting plug swivel neck Syn. for a water or a mud swivel in borehole drilling. Also called gooseneck. Long swivel plug See: hoisting plug swivel trough A short, adjustable-angle trough that permits turning the conveyor panline any amount up to 30 degrees , either to the right or to the left. The position of the swivel is controlled by a roof jack and a pendulum. Jones, 1 swivel vise A bench vise that may be rotated on its base to bring the work that it holds into better position. Crispin sycee silver Pure, uncoined, lump silver of various sizes, usually stamped with a banker's or assayer's seal; used by the Chinese as a medium of exchange and reckoned by weight. The larger 3207

lumps, sometimes called shoes, are boat shaped and weigh about 1 lb troy (370 g). Standard, 2 syenite A group of plutonic rocks containing alkali feldspar (usually orthoclase, microcline, or perthite), a small amount of plagioclase (less than in "monzonite"), one or more mafic minerals (esp. hornblende), and quartz, if present, only as an accessory; also, any rock in that group; the intrusive equivalent of "trachyte." With an increase in the quartz content, syenite grades into "granite." Its name is derived from Syene, Egypt. A.G. Werner in 1788 applied the name in its present meaning; the Egyptian rock is a granite containing much quartz. syenodiorite A group of plutonic rocks intermediate in composition between syenite and diorite, containing both alkali feldspar (usually orthoclase) and plagioclase feldspar, commonly more of the former; also, any rock in that group. Generally considered a syn. of monzonite, but may also include both monzonite and rocks intermediate between monzonite and diorite (Streckeisen, 1967). See also: monzonite syenogabbro A plutonic rock differing in composition from gabbro by the presence of alkali feldspar. AGI sylvane Former name for native tellurium and for sylvanite. sylvanite a. A monoclinic mineral, 2[AuAgTe4 ] ; soft; metallic; commonly in implanted crystals resembling written characters; sp gr, 8.1; in quartz veins; a source of gold and silver. Also spelled silvanite. Syn: graphic ore; graphic tellurium; white tellurium; yellow tellurium; goldschmidtite. b. An old name for native tellurium. Dana, 1 sylvester A hand-operated device for withdrawing supports from the waste or old workings. The appliance enables a leverage of about 30 to 1 to be applied. A long chain allows it to be positioned a safe distance from the support to be extracted. It may also be used for applying tension or for moving machines short distances. See also: tension end; monkey winch. Nelson 3208

Sylvester process A three-step method for the recovery of manganese and iron from open-hearth slag and low-grade ores. Osborne sylvine The name for potassium chloride found native in the salt deposits at Stassfurt, Germany. See also: sylvite sylvinite A mining term for the mixtures of sylvite and halite occurring in the Prussian salt deposits; mined as potassium ore. English; AGI sylvite An isometric mineral, 4[KCl] ; cubic cleavage; bitter salty taste; soft; white; in evaporite deposits and around fumaroles; the chief source of potassium. Syn: sylvine; leopoldite. symbiosis Two or more organisms living together to the mutual benefit of both. Rogoff symbol A diagram, design, letter, color hue, abbrev., or other graphic device placed on maps, charts, and diagrams, that by convention, usage, or reference to a legend is understood to represent a specific characteristic, feature, or object, such as structural data, rock outcrops, or mine openings. AGI symbols of crystal faces a. The mathematical expressions for designating the position of crystal faces on coordinate axes. See also: Miller indices; plane. b. Any sign or letter used in crystallography to designate a group of smaller faces. AGI symmetrical dispersion In optical mineralogy, the dispersion that produces an interference figure with color distribution symmetrical to the trace of the axial plane and also to a line normal to it. symmetrical fold

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A fold whose limbs have the same angle of dip relative to the axial surface. CF: asymmetric fold symmetric spread See: split spread symmetry a. Symmetry in crystallography results from periodic repetition. A symmetry element is the geometrical locus about which a group of repeating operations acts. It may be a center, a mirror plane, or a rotation axis. b. A symmetry group is a collection of symmetry elements that may intersect at a point (point group) or that may be distributed in three-dimensional space (space group). See also: point group c. The symmetry of a fabric is the combined symmetry of all the elements making up the fabric. There are five possible symmetries: (1) spherical, for fabrics having the symmetry of a sphere; (2) axial, for fabrics having the symmetry of a spheroid; (3) orthorhombic, for fabrics having the symmetry of a triaxial ellipsoid; (4) monoclinic, for fabrics having one unique plane of symmetry; and (5) triclinic, for fabrics having no planes of symmetry. symmetry axis See: axis of symmetry; crystal axis. symon Red shale, Shropshire, United Kingdom. See also: calamanco symond strings Thin veins of calcium carbonate running through the coal. Also spelled simon strings. symon fault A syn. of horseback, named after such a structure in the Coalbrookdale coalfield of England that was originally thought to be a large fault. See also: horseback Symon's cone crusher A modified gyratory crusher used in secondary ore crushing that consists of a downward-flaring bowl within which is gyrated a conical crushing head. The main shaft is gyrated by means of a long eccentric that is driven by bevel gears. See also: gyrasphere crusher Symon's disk crusher 3210

A mill in which the crushing is done between two cup-shaped plates that revolve on shafts set at a small angle to each other. These disks revolve with the same speed in the same direction and are so set as to be widest apart at the bottom. Feed is from the center, and the material is gradually crushed as it nears the edge and is then thrown out by centrifugal force. Liddell sympathetic detonation a. Detonation of an explosive material by means of an impulse from another detonation through air, earth, or water. Dick, 1 b. The initiation of an explosive charge without a priming device by the detonation of another charge close by. Syn: flash over symplectic Said of a rock texture produced by the intimate intergrowth of two different minerals; sometimes the term is restricted to such textures of secondary origin. One of the minerals may assume a vermicular habit. Also, said of a rock exhibiting such texture, or of the intergrowth itself; i.e., symplectite. Also spelled: symplektic; symplectitic; symplektitic. CF: dactylitic symplectite An intimate intergrowth of two different minerals, sometimes restricted to those of secondary origin; also, a rock (igneous or thermally metamorphosed) characterized by symplectic texture. Also spelled: symplektite. CF: pegmatite symplesite A triclinic mineral, Fe3 (AsO4 )2 .8H2 O ; vivianite group; dimorphous with parasymplesite; soft. symptomatic mineral See: diagnostic mineral synadelphite A triclinic mineral, (Mn,Mg,Ca,Pb)9 (AsO3 )(AsO4 )2 (OH)9 .2H2 O(?) ; pseudoorthorhombic. synantetic Proposed by Sederholm and applied to those primary minerals in igneous rocks that are formed by the reaction of two other minerals, as in kelyphite rims, reaction rims, etc. Johannsen 3211

synchisite A rare, weakly radioactive, orthorhombic or monoclinic mineral, Ca(Ce,Nd,Y,La)(CO3 )2 F , usually found in pegmatites associated with aegirite, microcline, astrophyllite, fluorite, gadolinite, xenotime, cordylite, and catapleiite. May be related to parisite. Also spelled synchysite. Crosby synchromesh A silent-shift transmission construction in which hub speeds are synchronized before engagement by contact of leather cones. Nichols, 1 synchronal See: synchronous synchroneity The state of being synchronous or simultaneous; coincident existence, formation, or occurrence of geologic events or features in time, such as glacial synchroneity. Syn: synchronism synchronic See: synchronous synchronism The state when the phase difference between two or more periodic quantities is zero; they are then said to be in phase. See: synchroneity synchronous Occurring, existing, or formed at the same time; contemporary or simultaneous. The term is applied to rock surfaces on which every point has the same geologic age, such as the boundary between two ideal time-stratigraphic units in continuous and unbroken succession. It is also applied to growth (or depositional) faults and to plutons emplaced contemporaneously with orogenies. CF: isochronous; diachronous. Syn: synchronal; synchronic. AGI synchronous motor This type of motor has a stator similar to a squirrel cage motor, but the rotor has a directcurrent field winding with salient poles equal in number to the stator poles. The direct current is supplied to the field winding through slip rings. In addition to the direct3212

current field windings, the rotor normally has a squirrel cage (amortisseur) winding that is used for starting. Pit and Quarry synchysite Orthorhombic minerals, synchysite-(Ce) CaCe(CO3 )2 F , synchysite-(Nd) CaNd(CO3 )2 F , and synchysite-(Y) CaY(CO3 )2 F (doverite) of the bastnaesite group; pseudohexagonal. See: doverite synclinal An obsolete form of syncline.--adj. Pertaining to a syncline. CF: anticlinal synclinal axis In geology, the central line of a syncline, toward which the beds dip from both sides. See also: axis synclinal mountain A mountain whose geologic structure is that of a syncline. CF: anticlinal mountain synclinal valley A valley whose geologic structure is a syncline. CF: anticlinal valley syncline A fold in which the core contains the stratigraphically younger rocks; it is generally concave upward. CF: anticline synclinal. AGI synclinorium a. A compound syncline; a closely folded belt, the broad general structure of which is synclinal. Also called synclinore. b. A major syncline composed of many smaller folds. See also: geosyncline syndicate man In bituminous coal mining, a person who works with a party of miners who operate machines for undercutting, drilling, and loading coal into cars at the working face and are paid on a basis of tonnage of coal mined. DOT synergism 3213

a. Action of two agents, usually two chemicals, to produce an end effect greater than or different from the sum of the effects of the two agents acting separately. b. Used in metallurgy with reference to reagent combinations to obtain the maximum possible recovery of ore or metal. Nelson synform A fold whose limbs close downward in strata for which the stratigraphic sequence is unknown. CF: syncline; antiform. AGI syngenetic a. Said of a mineral deposit formed contemporaneously with, and by essentially the same processes as, the enclosing rocks. CF: epigenetic AGI b. Said of a primary sedimentary structure, such as a ripple mark, formed contemporaneously with the deposition of the sediment. AGI syngenetic deposit A deposit formed contemporaneously with the parent rock and enclosed by it. There are two types of syngenetic deposits, igneous and sedimentary. Some examples are nickeliferous sulfides, nontitaniferous magnetite, diamond, chromite, and corundum. Lewis synkinematic See: syntectonic synneusis A mechanism by which small plagioclase crystals float into growing phenocrysts of potassium feldspar. Also, said of the texture of a rock showing such crystals. Etymol: Greek, to swim together. AGI synorogenic Said of a geologic process or event occurring during a period of orogenic activity; or said of a rock or feature so formed. CF: syntectonic AGI synorogenic pluton An igneous intrusion emplaced during a period of orogenic activity. AGI syntaxy 3214

An intergrowth between two mineral species in which single or multiple unit cells coincide in size and shape, e.g., bastnaesite-synchisite. CF: distaxy; epitaxy; topotaxy; polycrystal. syntectic The adj. of syntexis. syntectite A rock formed by syntexis. syntectonic Said of a geologic process or event occurring during any kind of tectonic activity, or of a rock or feature so formed. CF: synorogenic Syn: synkinematic syntexis a. The formation of magma by melting of two or more rock types and assimilation of country rock; anatexis of two or more rock types. AGI b. Modification of the composition of a magma by assimilation. AGI c. Any kind of reaction between a rising body of magma and the crustal rocks with which it comes into contact.--Adj: syntectic. See also: anatexis synthesis The production of a chemical compound by the union of elements or of simpler compounds or by the degradation of a complex compound, esp. by laboratory or industrial methods. synthetic See: synthetic stone synthetic diamond a. A diamond produced artificially by subjecting a carbonaceous material to extremely high temperature and pressure; currently and commonly called MM and/or manmade diamond. See also: manmade diamond b. A misnomer for sintered tungsten carbide. Long synthetic gem One artificially made from chemicals. Schaller 3215

synthetic mineral An artificial substance having all the properties of a mineral. Hurlbut synthetic ore Material that is the equivalent of, or better than, natural ore, can be put to the same uses, and is produced by means other than ordinary concentration, calcining, sintering, or nodulizing. synthetic ruby In chemical composition and in all their physical characters, including optical properties, synthetic ruby and synthetic sapphire are true crystalline ruby or sapphire, but they are produced in quantity in the laboratory by fusing pure precipitated alumina with a predetermined amount of pigmentary material. They can be distinguished from natural stones only by the most careful examination. Syn: synthetic sapphire synthetic sapphire See: synthetic ruby synthetic stone A man-made stone that has the same physical, optical, and chemical properties, and the same chemical composition, as the genuine or natural stone that it reproduces. Many gem materials have been made synthetically as a scientific experiment, but only corundum, spinel, emerald, rutile, garnet, quartz, chrysoberyl (alexandrite), opal, and turquoise have been made commercially and cut as gemstones for the jewelry trade. Syn: imitation syntron feeder A feeder placed under a bin, hopper, or ore pass opening (or raise) that vibrates by the use of magnetic force to distribute ore evenly onto a moving conveyor belt. It can by adjusted to regulate the flow through various degrees of vibration. syphon brick A brick for tapping metal from the cupola, the primary object of which is to eliminate the tapping and botting up of the cupola tap hole each time metal is drawn off. With the syphon brick, the orifice from which the metal is drawn is continually open to the atmosphere, and the flow of metal is controlled by shutting the blast on and off. The case of control permits the use of quite small ladles at the cupola, so that there is no need for redistribution from large to small ladles. Osborne 3216

Syrian garnet Trade name for almandine garnet, of gem stone quality. CTD sysertskite Former name for iridosmine. system a. A standard, worldwide division; contains rocks formed during a fundamental chronologic unit, a period. An example is the Devonian system. AGI b. The fundamental time-rock unit is the system. AGI c. In crystallography, the division of first rank, in the classification of crystals according to form. The six systems ordinarily recognized are the isometric, tetragonal, hexagonal, orthorhombic (or rhombic), monoclinic, and triclinic; some divide the hexagonal system into hexagonal and trigonal. d. Applied to the sum of the phases that can be formed from one, two (binary system), three (ternary system), or more components under different conditions of temperature, pressure, and composition. Holmes, 2 e. The term system or general system of work means simply that the work, as it is commenced on the ground is such that, if continued, will lead to a discovery and development of the veins or orebodies that are supposed to be in the claim, or, if these are known, that the work will facilitate the extraction of the ores and mineral. Ricketts systematic error Any error that persists and cannot be considered as due entirely to chance, or an error that follows some definite mathematical or physical law or pattern and that can be compensated, at least partly, by the determination and application of a correction; e.g., an error whose magnitude changes in proportion to known changes in observational conditions, such as an error caused by the effects of temperature or pressure on a measuring instrument or on the object to be measured. CF: random error systematic sampling error a. An error that arises from some basic defect in the sampling or preparation process such that the result obtained is always either higher or lower than the true figure. Systematic errors are additive; i.e., if there are two sources of error, the total error is obtained by adding the individual errors. Nelson b. An error due to some known physical law by which it might be predicted; those errors produced by the same cause affect the mean in the same sense and do not tend to balance each other but rather give a definite bias to the mean. An error that results from some bias in the measurement process and is not due to chance, in contrast to random error. McGraw-Hill, 1 systematic support 3217

The setting of timber or steel supports regularly at fixed intervals irrespective of the condition of the roof and sides; a support in accordance with a system specified in rules made by the manager of the mine. Nelson systematic timbering Placing mine timbers according to a predetermined plan, regardless of roof conditions. Zern systems of crystals The seven large divisions into which all crystallizing substances can be placed, namely isometric (or cubic), tetragonal, hexagonal, trigonal, orthorhombic (or rhombic), monoclinic, and triclinic. This classification is based on the degree of symmetry displayed by the crystals. CMD szaibelyite A white to yellow acicular mineral, MgBO2 (OH) . Probably orthorhombic. Occurs in nodules; related to camsellite. Syn: ascharite Larsen; Dana, 2 szaskaite See: smithsonite szomolnokite A monoclinic mineral, FeSO4 .H2 O ; kieserite group.

T taaffeite A hexagonal mineral, BeMg3 Al8 O16 ; hoegbomite group; a dimorph of musgravite; violet-red. tab Token, check, tally. Syn: teller tabasheer

3218

Translucent to opaque and white to bluish white opaline silica of organic origin (deposited with the joints of a bamboo shoot), valued in the East Indies as a medicine and used in native jewelry. Also spelled tabaschir or tabashir. tabby A mixture of lime with shells, gravel, or stones in equal proportions, with an equal proportion of water, forming a mass that when dry becomes as hard as rock; a substitute for bricks or stone in building. Fay Tabbyite Trade name for a variety of solid asphalt found in veins in Tabby Canyon, UT. table a. See: rotary table crushed particles of ore or coal from gangue. Weed, 2 c. In placer mining, a wide, shallow sluice box designed to recover gold or other valuable mineral from screened gravel. See also: undercurrent Hess table cut a. An early style of fashioning diamonds in which opposite points of an octahedron were ground down to squares to form a large cutlet and a larger table, the remaining parts of the eight octahedral faces being polished. b. A term used somewhat loosely to describe any one of the variations of the "bevel cut," provided it has the usual large table of that cut. Syn: bevel cut table diamond A relatively flat diamond of table cut. Webster 3rd table flotation Flotation process practiced on a shaking table. Ore or coal is ground, deslimed, conditioned, and fed to table as thick slurry. Flotable particles become glomerules, held together by minute air bubbles and edge adhesion. These roll across and are discharged nearly opposite the feed end. The process is helped by jets of low-pressure air from piping set across table. Tailings work along deck to discharge end. Pryor, 3 tableland a. A general term for a broad, elevated region with a nearly level or undulating surface of considerable extent; e.g., South Africa. AGI b. A plateau bordered by abrupt clifflike edges rising sharply from the surrounding lowland; a mesa. AGI 3219

table spar See: tabular spar; wollastonite. tabling Separation of two materials of different densities by passing a dilute suspension over a slightly inclined table having a reciprocal horizontal motion or shake with a slow forward motion and a fast return. Bennett tabular a. Said of a feature having two dimensions that are much larger or longer than the third, such as a dike, or of a geomorphic feature having a flat surface, such as a plateau. AGI b. Said of the shape of a sedimentary body whose width to thickness ratio is greater than 50:1, but less than 1,000:1 (Krynine, 1948); e.g., a graywacke formation in a geosynclinal deposit. CF: blanket; prism. AGI c. Said of a sedimentary particle whose length is 1.5 to 3 times its thickness (Krynine, 1948). CF: prismatic d. Said of a metamorphic texture in which a large proportion of grains are tabular and have approximately parallel orientation (Hart, 1977) AGI e. Said of a crystal form that shows one dimension markedly smaller than the other two. f. Tabular crystals, such as wollastonite, may occur in tables, plates, disks, foliae, and scales. Schieferdecker; AGI g. A mineral showing broad, flat surface, e.g., wollastonite. Nelson h. See: tabular deposit i. Refers to crystals that have three distinctly different dimensions. CF: acicular; anisodesmic; equant. tabular crystal A crystal flattened parallel to any face. Standard, 2 tabular deposit A flat tablelike or stratified bed; e.g., a coal seam. See: tabular Nelson tabular spar Wollastonite in tabular form. Syn: table spar tabular structure The structure of a mineral or rock that makes it tend to separate into plates or laminae. AGI Taby cut 3220

A modified double-spiral cut, the benefits of which are that the holes are located vertically below one another on one and the same line to facilitate drilling. Langefors tacharanite A monoclinic mineral, Ca12 Al2 Si18 O51 .18H2 O . tacheometer See: tachymeter; subtense bar. tachometer An instrument for measuring speed. In mining it is used on hoists lifting cages, cars, or skim in shafts or slope. Zern tachyhydrite A trigonal mineral, CaMg2 Cl6 .12H2 O . Also spelled tachydrite or tachhydrite. tachymeter A surveying instrument designed for use in the rapid determination from a single observation of the distance, direction, and elevation difference of a distant object; esp. a transit or theodolite with stadia hairs, or an instrument in which the base line for distance measurements is an integral part of the instrument. Syn: multiplying constant; tacheometer. AGI tachymetry A method of rapid surveying using the tachymeter; e.g., the stadia method of surveying used in United States. AGI tack a. A small pillar of coal. Fay b. Veinstone; gangue, etc. See also: taking tackey Having a rough, catchy surface. Gordon tackle An assemblage of ropes or wire cables and pulleys arranged for hoisting or pulling. Long 3221

Tacoma process An electrolytic method for the production of iron powder. Osborne taconite a. A local term used in the Lake Superior iron-bearing district of Minnesota for any bedded ferruginous chert or variously tinted jaspery rock, esp. one that enclosed the Mesabi iron ores (granular hematite); an unleached iron formation containing magnetite, hematite, siderite, and hydrous iron silicates (greenalite, minnesotaite, and stilpnomelane). The term is specif. applied to this rock when the iron content, either banded or disseminated, is at least 25%. Also spelled taconyte. AGI b. Since World War II, a low-grade iron formation suitable for concentration of magnetite and hematite by fine grinding and magnetic treatment, from which pellets containing 62% to 65% iron can be produced. AGI taconite ore A type of highly abrasive iron ore now extensively mined in the United States. Sandstrom taconyte See: taconite tactite A rock of complex mineralogical composition, formed by contact metamorphism and metasomatism of carbonate rocks. It is typically coarse-grained and rich in garnet, ironrich pyroxene, epidote, wollastonite, and scapolite. Approximate syn: skarn. See also: calc-silicate hornfels taeniolite A monoclinic mineral, KLiMg2 Si4 O10 F2 ; mica group; at Narsarsuk, Greenland, and Magnet Cove, AR. Also spelled tainiolite. taenite An isometric mineral, (Fe,Ni) ; contains 27% to 65% nickel; occurs in iron meteorites as lamellae or strips flanking bands of kamacite. Also called gamma-nickel-iron (facecentered cubic). See also: nickel iron tag 3222

A numbered piece that a miner attaches to or places on each car a miner loads. The tag is removed at the tipple where the car is credited to the miner. See also: tally; ticket. CF: wedge rock tagged atom See: tracer Tagg's method a. A graphical method of determining the resistivity of the ground. AGI b. A method of interpretation of resistivity sounding data obtained with a Wenner array over a twolayered Earth. AGI tagilite See: pseudomalachite tagline A line from a crane boom to a clamshell bucket that holds the bucket from spinning out of position. Nichols, 1 tail a. (also plural). The inferior, less valuable, or refuse part of anything; foots, bottoms, dregs; sediment. See also: tailings b. The poor grade of ore slime at the lower end of the slime box as it flows from the stamps. Standard, 2 c. The unexposed end of a brick or stone in a wall; a tailing. Standard, 2 d. The rear of a shovel deck. Nichols, 1 e. The anchor end of a cable excavator. Nichols, 1 f. A bar or barrier formed behind a small isle or a skerry. Also called trailing spit; banner bank. Schieferdecker tail anchor The anchor for a track cable, or the turn point for a backhaul line in a cable excavator. Nichols, 2 tail beam A joist or beam that abuts against the header joist. Syn: tail joist Crispin tailblock a. The boom foot and idler sprocket assembly on a ladder ditcher. Nichols, 1 b. The block used to pull a slusher to the face. 3223

tailboard See: tailgate tail chain A chain used in mine haulage; also, tail rope. Korson tail crab In mining, a crab or winch for operating a tail rope. Standard, 2 tailend a. That part of a mining belt conveyor that consists of the tail section and, when required, a belt takeup, a telescopic section, and a loading station. NEMA, 2 b. The end of a conveyor remote from the delivery point. See also: tension end tailend loading station See: loading station tailgate A subsidiary gate road to a conveyor face as opposed to a main gate. The tailgate commonly acts as the return airway and supplies road to the face. Syn: barrier gate; tailboard. See also: bottom gate tail house The buildings in which tailings are treated. Fay tailing a. Giving the proper angle, or elevation, in driving the poling boards in a heading. Stauffer b. The part of a projecting brick or stone inserted in a wall. Crispin tailing pit See: catch pit tailing pond Area closed at lower end by constraining wall or dam to which mill effluents are run. Clear water may be returned after settlement in dam, via penstock(s) and piping. Pryor, 3 3224

tailings a. The gangue and other refuse material resulting from the washing, concentration, or treatment of ground ore. See also: tail Webster 3rd b. Those portions of washed ore or coal that are regarded as too poor to be treated further Standard, 2 c. Applied to sectional residue, e.g., table tailings, which is the residue from shaking screens and tables. Nelson d. The reject from froth flotation cells. BS, 5 tailings dam One to which slurry is transported, the solids settling while the liquid may be withdrawn. Pryor, 3 tailings machine A machine for sifting the tailings and collecting the gold from the detritus after it has passed through the washer. Nelson tailings settling tank A vessel to remove solids from the tailings effluent as in a coal washery. The tank is about 60 ft (18 m) in diameter and 10 ft (3 m) deep. The tailings are fed in at the center with a flocculant. As the suspension travels from the center to overflow at the perimeter of the tank, the solids settle out and the clear water overflows, is collected, and is returned to the washer for reuse. Nelson tailings wheel A wheel carrying buckets or compartments on the periphery and used in conveying liquid, pulp, or sand from a lower to a higher level. Fay tail joist A joist that has one end terminating against a header joist. See: tail beam taillight A light carried at the back end of a car, train, trip, or movable machinery. tail of water The edge of water standing in mine workings. BS, 10 tail pipe 3225

The suction pipe of a pump. Fay tail pulley a. The terminal pulley at the end of the conveyor opposite the normal discharge end. It is usually an idler pulley but may be a drive pulley. NEMA, 2 b. The pulley or roller in the tail or foot section of a belt conveyor around which the belt runs. Also known as footsection pulley. Jones, 1 tailrace A trough or channel used for conveying the tailings; a channel for conducting water away from any plant or works. Nelson tail rope a. The rope that passes around the return sheave in main-and-tail haulage or a scraper loader layout. See also: main rope b. The rope used to draw the empties back into a mine in a tail-rope haulage system. Zern c. A counterbalance rope attached beneath a cage when the cages are hoisted in balance. Zern d. A hemp rope used for moving pumps in shafts. Fay tail-rope boy See: tail-rope coupler tail-rope coupler In bituminous coal mining, one who works on a tail-rope haulage system, removing the haulage-cable hook from the rear of a train of empty cars that has been lowered down an inclined haulageway, and attaching the hook to the front of a train of loaded cars to be hauled to the surface. Also called tail-rope boy. DOT tail-rope engineer In bituminous coal mining, one who operates a hoisting engine that draws the cable of a tail-rope haulage system used to raise and lower mine cars on tracks between the surface and a level in a mine. DOT tail rope fireman In bituminous coal mining, a person who fires the boiler supplying steam for the engine that powers the tail-rope haulage system, a type of cable haulage used to raise and lower cars along an incline between the surface and a level in a mine. DOT 3226

tail-rope haulage A single track system of rope haulage in which a double-drum haulage engine at the unloading terminal winds the main rope on one drum. The train or trip of cars is connected to the other end of the main rope and also to a tail rope that extends to the inner terminal in the mine, around a tail sheave, and then back over idler sheaves at one side of the haulageway to the other drum at the haulage engine. See also: rope haulage tail-rope man See: tail-rope rider tail-rope rider In bituminous coal mining, one who works on trains of cars hauled by tail-rope haulage system at mine, coupling and uncoupling cars, and hooking and unhooking cable to and from trains. Also called tail-rope man. DOT tail-rope system A method of haulage in which one rope--the main rope--is attached to the front end of a trip of cars and another rope--the tail rope--is attached to the rear end of the trip. It is operated by a hoisting engine and two separate drums. Hudson tails Can. Portion of tailings containing some mineral that cannot be economically removed. This is constantly assayed as it leaves the treatment plant so that recovery can be known and controlled at all times. CF: heads tail section The part of a mining belt conveyor that consists of the tail pulley, the framing, belt idlers if included, and means for attaching a belt takeup. NEMA, 2 tail shaft The shaft in the tail or foot section of a belt or chain conveyor that supports either the tail pulley or the tail sprocket. Jones, 1 tail sheave a. An arrangement whereby a sheave is placed at the bottom of a shaft, and a rope is fastened to the bottom of one cage and then passed down around the sheave and up to the bottom of the cage in the other compartments; thus practically complete balancing is 3227

effected. Lewis b. The pulley around which the tail rope of a scraper loader or main-andtail haulage passes. See also: turn pulley tail swing The clearance required by the rear of a revolving shovel. Nichols, 1 tail-track system The simplest form of track layout for car or trip loading. In this system, the track can merely be extended down the heading, or it can be turned right or left, and then turned back, U-fashion, in an adjacent heading. The major disadvantage is that trips must come out the same way they go in, meaning increased loss of time unless the changing track is very close. Coal Age, 3 tail water The water downstream from a structure, as below a dam. AGI tainiolite See: taeniolite take a. A mineral-bearing area that a mine is permitted to work. Also called holding; parcel; taking. BS, 7 b. The area or extent of coal that a coal mine owner has the right, under a lease, to mine and extract. See also: concession system; royalty. Nelson c. Eng. The extent or area of a lease of mineral property, often several thousand acres. Fay d. Lanc. To show or reveal gas. Fay takeout Cumb. An outcrop. As a verb, to crop out. Fay take the air a. To measure the ventilating current. Fay b. Applied to a ventilating fan as working well, or working poorly. Fay takeup a. In a belt-conveyor system, a tensioning device such as a carriage-mounted weight free to run downslope or a takeup pulley with weights hanging vertically below the belt near 3228

the feed end. Pryor, 3 b. Any device for taking up slack or removing the looseness of parts due to wear or other cause. Crispin c. See: chain takeup takeup pulley An idler pulley so mounted that its position is adjustable to accommodate changes in the length of the belt as may be necessary to maintain proper belt tension. NEMA, 2 taking Eng. A mineral-land lease. See also: take; tack. Fay takyr A surface depression containing clay and evaporites in south-central Asia. Also spelled takir. Talbot continuous process A pig iron and ore process that depends upon the rapid oxidation of the impurities contained in pig iron by a liquid, highly ferruginous slag and that is carried out in the basic open-hearth furnace, generally of the tilting type. The essential feature of the process is to retain a certain amount of metal in the furnace (1) to dilute the impurities contained in the additions of pig iron, and (2) to supply the heat necessary to keep the slag very fluid. Osborne Talbot process A process for protecting the inside of cast-iron pipes with a coating of sand and bitumen. Hammond talc a. A monoclinic and triclinic mineral, 2[Mg6 (OH)4 (Si8 O20 )] ; basal cleavage; soft; has a greasy or soapy feel; easily cut with a knife; occurs as hydrothermal alteration of ultramafic rocks, low-grade metamorphism of siliceous dolomites in foliated, granular, or fibrous masses; an insulator, ceramic raw material, and lubricant. Originally spelled talck. See also: steatite; soapstone. b. In commercial usage, a talcose rock; a rock consisting of talc, tremolite, chlorite, anthophyllite, and related minerals. Syn: talcum talcite a. A massive variety of talc. Fay b. Damourite, a soapy-feeling hydromuscovite. talcoid 3229

Resembling talc, as talcoid schist. Fay talcose a. Pertaining to or containing talc; e.g., talcose schist. b. Resembling talc; e.g., a talcose rock that is soft and soapy to the touch. talc schist A schist in which talc is the dominant schistose mineral. Common associates are mica and quartz. AGI talcum See: talc; soapstone. talking Applied to a series of small bumps or cracking noises within the walls. Bumping, talking, and spitting are signs that the rock is beginning to yield to the stresses and indicate a change in conditions within the rock. Spalding tallow drop A style of cutting precious stones in which the stone is domed on one or both sides. Fay tallow peat Ir. A variety of highly flammable peat. Tomkeieff tallow top A precious stone with a very rounded front and a flat back. Standard, 2 tally a. A mark or number placed on every car of coal or ore a miner sends out, usually a metal ticket. By counting these, a tally is made of all the cars the miner sends out. See also: tab; tag; ticket. Fay b. A brass tag attached to a chain at every tenth link, and so marked or shaped as to enable the position of the tally along the chain to be immediately read. CTD tally boy See: tally shouter 3230

tallyman See: chute checker tally shouter A laborer who calls out the number chalked on each loaded mine car, as it is run on scales for weighing, so that the weighmaster can identify for pay purposes the miner who loaded the car. Syn: tally boy talus Rock fragments of any size or shape (usually coarse and angular) derived from and lying at the base of a cliff or very steep, rocky slope. Also, the outward sloping and accumulated heap or mass of such loose broken rock, considered as a unit, and formed chiefly by gravitational falling, rolling, or sliding. See also: scree talus creep The slow downslope movement of talus, either individual rock fragments or the mass as a whole. AGI talus fan See: alluvial fan tam-o-shanter A very fine-grained, soft, gritty, natural stone found in Scotland. Fay tamp a. To tightly pack a drilled hole with moist, loose material after the charge has been placed. Hudson b. To fill a charged shothole with clay or other stemming material to confine the force of the explosion. See also: stemming c. To ram or pound down ballast on a railway track, or road metal. CTD d. See: stem tamper a. In bituminous coal mining, one who fills drill holes in which explosives have been charged, by machine driller or miner, with clay or some other tamping material, using a tamping bar. Also called shot tamper. DOT b. An implement for tamping or compacting material; a tamping iron or tamping bar. Sometimes made of wood, copper, or iron with a copper tip. See also: tamping bar c. One who tamps. Standard, 2 d. A tool for compacting soil in spots not accessible to rollers. Nichols, 1 3231

tamping a. The act of inserting and packing explosives and stemming in a shothole. See also: stemmer b. The act of packing a drilled hole around a cartridge with fine dirt from the floor of a mine before blasting, to prevent a misdirection of the force of the blast. Korson c. The material placed over a charge in a borehole, to better confine the force of the explosion to the lower part of the hole. Stauffer d. Ramming down, as of ballast. Crispin e. The operation of compacting freshly placed concrete by repeated blows. Taylor f. The shaping of a semidry powder, e.g., of refractory material, in a mold by repeated blows delivered mechanically on the top mold plate. Dodd tamping bag A paper bag that is filled with good stemming material such as sand for use in horizontal and upward-sloping holes. Plastic bags are also available for this purpose. See also: tamp tamping bar A piece of wood the size of a broom handle for pushing explosive cartridges and stemming into shotholes. See also: tamper Hammond; von Bernewitz tamping plug A plug of iron or wood used instead of tamping material to close up a loaded blasthole. Standard, 2 tamping pole A pole of nonsparking material used to tamp in blast holes. Syn: loading pole tamping rod See: stemmer; stemming rod. tamping roller One or more steel drums, fitted with projecting feet, and towed by means of a box frame. Nichols, 1 tamping stick See: stemming rod tandem 3232

a. A double-axle drive unit for a truck or grader. A bogie. Nichols, 1 b. A pair in which one part follows the other. Nichols, 1 tandem drive A three-axle vehicle having two driving axles. Nichols, 1 tandem-drive conveyor A conveyor having a belt drive mechanism in which the conveyor belt is in contact with two drive pulleys, both of which are driven with the same motor. NEMA, 2 tandem hoisting Hoisting in a deep shaft with two skips running in one shaft. The lower skip is suspended from the tail rope of the upper skip. Both are loaded and discharged simultaneously. The upper one discharges at the surface and is loaded at a pocket halfway down the shaft. The lower skip is loaded at the shaft bottom and discharges at the half-way pocket. Thus, the rope on the winding drum is only equal to half the full depth. See also: two-stage hoisting tandem hydroseparator A two-celled hydroseparator with troughs. The raw coal feed is conveyed through a trough by water under pressure where the refuse stratifies to the bottom. The action in the first cell is that of a forceful upward current, which results in the removal of the heavy refuse. In the second cell a lighter current permits the settling of lighter and smaller refuse. The refuse settles to a perforated cell deck where it joins the slowly moving slate bed to the discharge. Refuse discharge is controlled by a refuse gate or hinged plate at the end of the cell bed. Kentucky Tandem support system A trade name for a longwall steel support system. It consists of two 50-st (45-t) chocks in line at right angles to the face and linked together with a double-acting ram. In operation, the front chock is lowered and advanced with the conveyor and reset to the roof; the rear chock is then lowered and brought forward. Nelson tandem unit panel A longwall conveyor face with two face conveyors of different capacities, one delivering on to the other--tandem fashion. The layout has the disadvantage that the whole tonnage of coal must be transported along the second conveyor, and any breakdown on the second conveyor will affect the output of the entire face. Nelson 3233

tanette A small hill covering a residual surface of laterite, frequently ore bearing. Hess tangawaite See: bowenite tangeite Former name for calciovolborthite. tangent a. A straight line that touches, but does not transect, a given curve or surface at one and only one point; a line that touches a circle and is perpendicular to its radius at the point of contact. AGI b. The part of a traverse included between the point of tangency (the point in a line survey where a circular curve ends and a tangent begins) of one curve and the point of a curvature (the point in a line survey where a tangent ends and a circular curve begins) of the next curve. AGI c. A great-circle line that is tangent to a parallel of latitude at a township corner in the U.S. Public Land Surveys system. AGI d. A term sometimes applied to a long straight line of a traverse whether or not the termini of the line are points of curve. AGI e. The ratio of the length of the leg opposite an acute angle in a right-angled triangle to the length of the leg adjacent to the angle. Adj. said of a line or surface that meets a curve or surface at only one point. AGI tangent distance The distance from the point of curvature to the point of intersection (vertex), or from the point of intersection to the point of tangency. See also: intersection point tangential stress a. Stress parallel to the tangent to the boundary of any opening. Obert b. See: shear stress tangent point The point at which a curve meets a straight line or another curve. Hammond tangent screw A very fine, slow-motion screw giving a tangential movement for making the final setting to a precision surveying instrument (such as for completing the alignment of sight 3234

on a theodolite or transit by gentle rotation of the reading circle about its axis). CF: Stebinger drum tangiwai A variety of serpentine used by the Maoris for ornaments. Similar to bowenite. See also: bowenite tangiwaite A term used by the Maoris of New Zealand for bowenite, a massive variety of antigorite. Also spelled tangiwai or tangawaite. tangle sheet Mica with intergrowths of crystals or laminae resulting in books that split well in some places but tear to produce a large proportion of partial films. Skow tank a. A large vessel or receptacle, made either of wood or of metal, intended to contain a fluid or gas, as water tank, gasoline tank. Syn: vat Fay b. A melting unit, in which the container for the molten glass is constructed from refractory blocks. ASTM tankage a. The act or process of storing oil, etc., in a tank. Fay b. The price charged or paid for storage in a tank. Fay c. The capacity of a tank or tanks. Fay d. The waste residue deposited in lixiviating vats or tanks. Fay tank furnace Essentially a large box of refractory material holding from 6 to 200 st (5.4 to 181 t) of glass, through the sides of which are cut ports fed with a combustile mixture (producer gas and air, coke oven gas and air, or oil spray and air), so that flame sweeps over the glass surface. With the furnace is associated a regenerative or recuperative system for the purpose of recovering part of the heat from the waste gas. CTD tank station See: station tantalite

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A mineral series ferrotantalite-manganotantalite; unless specified it refers to ferrotantalite, an orthorhombic mineral, FeTa2 O6; black; in pegmatites; the main source of tantalum. tantalum A rather brittle, lustrous, hard, heavy, gray metallic element. Symbol, Ta. Occurs principally in the mineral columbite-tantalite, (Fe,Mn)(Nb,Ta)2 O6 . Widely used to fabricate chemical process equipment, nuclear reactors, and aircraft and missile parts. Used to make electrolytic capacitors, vacuum furnace parts, and surgical appliances. Handbook of Chemistry and Physics, 3 tantalum borides Several borides are known, including the following: Ta B2 , melting point, 3,200 degrees C; sp gr, 12.5; thermal expansion, 5.5 X 10-6 ; TaB, melting point, 2,400 degrees C; sp gr, 14.3; Ta3 B4 , melts incongruently at 2,650 degrees C; sp gr, 13.6. Dodd tantalum nitrides Two nitrides are known: TaN, melting point, 3,090+ or -50 degrees C; Ta2 N , which loses nitrogen at 1,900 degrees C. Dodd tanteuxenite An orthorhombic mineral, (Y,Ce,Ca)(Ta,Nb,Ti)2 (O,OH)6 ; black. Syn: delorenzite tantite A possibly triclinic mineral, Ti2 O5 . Tanzanite A blue to violet gem variety of zoisite. tap a. To cut or bore into old workings or water-bearing strata for the purpose of proving or extracting gas or water. BS, 10 b. To intersect with a borehole and withdraw or drain the contained liquid as water from a water-bearing formation or from underground workings. Long c. To drive one passageway into another. Hudson d. To win coal in a new district. Fay e. A threaded cone-shaped fishing tool. It may be either an inside or an outside tap, depending on whether the tap fits into or over the outside of a piece being fished. Syn: tapered tap f. A quantity of a liquid, as molten metal from a furnace, run out 3236

at one time. Webster 3rd g. To drain a furnace. ASTM h. To remove excess slag from the floor of a pot furnace. ASTM tap bar A pointed bar by which a blast-furnace tap-hole is opened or the metal in a melting pot, etc., is tested. Syn: tapping bar tape A continuous ribbon or strip of steel, invar, dimensionally stable alloys, specially made cloth, or other suitable material, having a constant cross section and marked with linear graduations, used by surveyors in place of a chain for the measurement of lengths or distances. AGI tape corrections These are applied as a routine matter to slope, temperature, sag, standardization, gravity and sea level effect when measuring a length accurately with a tape. See also: precision; tension correction. Hammond taper A gradual and uniform decrease in size, as a tapered socket, a tapered shaft, a tapered shank. Crispin taper bit A long cone-shaped noncoring bit used in drilling blastholes and in wedging and reaming operations. When the nose of the bit is rounded and the overall shape resembles the silk end of a corncob, the bit often is called a corncob bit. CF: bullnose bit tapered core bit A core bit having a conical diamond-inset crown surface tapering from a borehole size at the bit face to the next larger borehole size at its upper, shank, or reaming-shell end, as from EX to AX, or BX to NX. Long tapered end An end of rope having a reduced diameter to facilitate threading the rope through fittings and over pulleys. Hammond tapered-flange beam 3237

The common form of rolled steel joist in which the inner surfaces of the flanges are tapered, normally at an angle of 98 degrees to the web. See also: web tapered reamer A reamer having a conical diamond-inset surface tapering from any borehole size at its lower (bit) end to the next larger borehole size at its upper (core barrel) end, such as EX to AX, AX to BX, BX to NX. Long tapered step-core bit See: tapered step-face bit tapered step-face bit A tapered core bit having the cutting face set in the same manner as a step-face bit. Long tapered tap See: tap taper-lock sprocket A sprocket with a split tapered bushing for rigid mounting on a shaft. Jackson, 1 taper of thread Measurement in inches of taper or slope for a 1-ft (0.3-m) length of the threaded section of rod or pipe. Brantly, 2 taper pin A straight-sided pin that is smaller at one end than at the other. Nichols, 1 taper rope A rope that has a gradually diminishing diameter from the upper to the lower end. The diameter of the rope is decreased by dropping one wire at a time at regular intervals. Both round and flat ropes may be made tapered, and such ropes are intended for deep shaft hoisting with a view to proportioning the diameter of the rope to the load to be sustained at different depths. Zern taper-type dropper

3238

A device by which straight-type wedge can be attached to a diamond-drill rod, lowered, and set in a borehole. Long tape-triangulation method A method of measuring mine roadway area in which a tape is stretched diagonally across the roadway. Offsets to the roof, floor, and sides are taken at right angles to the tape and on both sides of it. Alternatively, the floor of the cross section is divided into equal increments and vertical offsets to the roof are made at each division. Horizontal offsets to the sidewalls are made from the nearest adjacent vertical offsets. The measurements so obtained are plotted to scale, and the area of the resulting diagram is determined from the plot. Syn: mine roadway area measurement taphole A hole at or near the bottom of a furnace or ladle through which molten metal, matte, or slag can be tapped or drawn from a furnace. Also called tapping hole. Syn: metal notch tapiolite The mineral series ferrotapiolite-manganotapiolite. tappet a. A sliding member working in a guide, interposed between a cam and the push rod or valve system that it operates, to eliminate side thrust on the latter. CTD b. The collar under which a cam is inserted so as to lift a stamp. Also called disk. Fay tapping a. Opening the outlet of a melting furnace to remove molten metal. ASM, 1 b. Removing molten metal from a furnace. ASM, 1 c. The act of boring a hole into old workings to release gradually any accumulation of water and gas. This may be followed by driving an advance heading into the area. As the heading is extended, boreholes are kept in advance of the face to prevent the sudden breakthrough of water. See also: inrush of water tapping assembly A mechanical device consisting of a short piece of casing cemented in the collar of a borehole at the upper end of which is affixed a gate or large plug valve followed by a rod stuffing box. Utilizing this assembly, underground drilling can be accomplished safely in areas of high hydrostatic pressure. Long tapping bar 3239

See: tap bar tapping clay A plastic clay used in plugging the tap-hole of a smelting furnace. Standard, 2 tapping old workings Boring a hole into old workings to release gradually any accumulation of water and gas. The borehole tapping may be followed by driving an advance heading into the area. As the heading is extended, boreholes are kept in advance of the face to prevent the sudden breakthrough of water. See also: inundation; inrush of water. Nelson tar a. A thick brown to black viscous organic liquid, free of water, which is obtained by condensing the volatile products of destructive distillation of coal, wood, oil, etc. It has a variable composition, depending on the temperature and material used to obtain it. AGI b. Any of various dark brown or black, bituminous, usually odorous, viscous liquids or semiliquids that are obtained by the destructive distillation of wood, coal, peat, shale, and other organic material, and yield pitch on distillation. Webster 3rd c. Soft pitch or thickened petroleum, found in cavities of some limestones. Fay taramellite An orthorhombic mineral, Ba4 Fe4 (B2 Si8 O27 )O2 Cl ; forms a series with titantaramellite; forms reddish-brown radiating fibrous aggregates; at Candoglia, Piemont, Italy. taramite A monoclinic mineral, Na2 CaFe3 Al2 (Si6 Al2 )O22 (OH)2 ; amphibole group with magnesium replacing iron toward magnesiotaramite; black; at Wali-tarama, Mariupol, Ukraine. tarapacaite An orthorhombic mineral, K2 CrO4 ; has the olivine structure; yellow. tarasovite An interstratified mica and clay. tarbuttite 3240

A triclinic mineral, Zn2 (PO4 )(OH) ; forms a series with paradamite; at Broken Hill, Kabwe, Zambia. Syn: salmoite tare a. To weigh mine cars when empty in order to determine the weight of coal in a car when the loaded car is weighed, done at specific intervals so that miners paid on a tonnage basis may receive proper credit for coal that they have loaded. BCI b. Allowance for weight of packing or container in which goods are moved. The difference between gross and net weight. Pryor, 3 target a. Sliding weight on a leveling rod used in surveying, to enable the staffman to read the line of collimation. In underground leveling, a bead on a hanging plumbline used for the same purpose; distance from this to the roof or working is then measured. Pryor, 3 b. The point a borehole or exploration work is intended to reach. c. The distinctive marking or instrumentation of a ground point to aid in its identification on an aerial photograph. It is a material marking so arranged and placed on the ground as to form a distinctive pattern over a geodetic or other control-point marker, on a property corner or line, or at the position of an identifying point above an underground facility or feature. AGI d. The image pattern on an aerial photograph of the actual mark or target placed on the ground prior to photography. AGI e. The vane or sliding sight on a surveyor's level rod; a device, object, or point upon which sights are made. AGI target rod A type of leveling staff provided with a sliding target, which can be moved by the staffman, under direction from the leveler, to a position in which it is in line with the line of sight of the level, the staff reading being recorded by the staffman. CTD tarmacadam Asphalt that is made artificially from grit, crushed stone, or gravel and is bonded or coated with tar or a tarbitumen mixture. See also: premix Nelson tarnish A thin alteration film that forms on mineral surfaces, esp. on copper minerals, with color and luster different from that on fresh fractures. Tarnowitz process

3241

A metallurgical process in which large charges of lead ore are roasted at low temperatures in furnaces and treated substantially, such as in the Carinthian process. The residual containing considerable lead is remelted in special furnaces. Fay tarring a. The coating of piles used for permanent work with prepared acid-free tar before driving. The tar is obtained from the high-temperature carbonization of coal in horizontal retorts. Nelson b. The act of coating, (as of a pipe) with tar. task The number of tons or the amount of ore or material that can or should be loaded either by mechanical loaders or by hand loaders. Also called score. Jackson, 2 task training Specific training given to a miner prior to performing a task where the worker has had no previous work experience. CF: new miner training; refresher training. Federal Mine Safety Tasmanian alexandrite Alexandrite (chrysoberyl) of good gem quality from Tasmania, Australia. tasmanite An impure coal, transitional between cannel coal and oil shale. Syn: combustible shale; yellow coal; Mersey yellow coal; white coal. AGI tasmanite shale See: tasmanite tatarskite An orthorhombic mineral, Ca6 Mg2 (SO4 )2 (CO3 )2 Cl4 (OH)4 .7H2 O ; with anhydrite in saline strata of the Caspian depression. tator butt Shrop. Fragile sandstone. tautline cableway 3242

The tautline cableway differs from the aerial tramway in that its operation is limited to the distance between two towers (not more than 3,000 ft or 915 m apart), it has only one carrier, and the traction cable is reeved at the carrier so that loads can be raised and lowered. Also, the tautline cableway is not restricted to a fixed position; the towers can be mounted on trucks or crawlers, and the machine then can be shifted across a wide area. The machine will hoist loads from any point under the span, convey these loads in either direction, and lower these loads at any point under the span. By using movable towers, an area of any length can be traversed. Equipped with slings, this machine will pick up and carry unwieldy loads of every kind; then by exchanging the slings for a skip, it will handle large chunks of ore, stone, etc., or it can be equipped with a dump bucket to handle any bulk material, including semifluid mixtures. Pit and Quarry tautomeric Descriptive term for amphoteric substance, able to react in accordance with two oppositely directed structural arrangements of its atoms. Pryor, 3 tavistockite An old name for an apatite mineral. tavorite A triclinic mineral, LiFe(PO4 )(OH) ; amblygonite group; forms green or yellow finegrained aggregates; in Brazil. tawmawite A yellow to green to dark-green variety of epidote containing chromium; occurs in Tawmaw, upper Burma (Myanmar). taxoite Serpentine from Chester County, PA. Schaller taylorite a. An obsolete name for bentonite; named after William Taylor who made the first commercial shipments of the clay from the Rock Creek district, Wyoming. b. A variety of arcanite containing ammonium found in guano beds on islands off Peru. Taylor producer A furnace used for the manufacture of producer gas. Fay 3243

Taylor-White process A process for heat-treating high-speed steels. Webster 3rd T-bolt A bolt with a T-shaped head, made to fit into a T-shaped slot in a drill swivel head; by means of it the swivel head can be turned to any angle of inclination to drill a borehole. Also, a similar bolt made to fit into a T-slot in the bed of a machine, for the purpose of holding a piece of metal to be machined or to fasten a machine to its base. Long tchesa stick a. An igniting stick used to light powder fuses when firing a round of shots. Also called a fire stick. Pryor, 3 b. A paper shell about 1/4 in (0.64 cm) in diameter and 8 in (20.3 cm) long, filled with a balanced combustible that gives a strong spitting flame of 4 min duration. This device requires the individual lighting of each fuse. Lewis c. See: fuse lighter T-chisel A boring tool with its cut-edge made in the form of the letter T. Fay teallite An orthorhombic mineral, (Pb,Sn)S ; perfect basal cleavage; soft; blackish gray; sp gr, 6.4; in veins; a source of lead and tin. teardrop set A surface-set damond-bit crown molded in a die, prepared so that each inset diamond is backed by a raised teardrop-shaped mound of matrix metal. Long tear fault A steep to vertical fault associated with a low-angle overthrust fault and occurring in the hanging wall. It strikes perpendicular to the strike of the overthrust; displacement may be horizontal, and there may be a scissor effect. It is considered by some to be a type of strike-slip fault. AGI teary ground a. Ground easily broken and worked. Gordon b. Corn. A lode or stratum that breaks easily by reason of many joint planes. Fay 3244

teasing rods Light iron rods, about 2 ft (0.6 m) long, hinged together to form one continuous length of 40 to 60 ft (12 to 18 m). They are pushed up inside a drainage borehole casing to clear stoppages of pebbles and gravel, thus allowing the drainage water to flow freely. Eng. Min. J., 1 teaze hole The opening of a glass furnace through which fuel is introduced. Standard, 2 tectogene a. A long, relatively narrow unit of downfolding of sialic crust considered to be related to mountain-building processes. AGI b. The downfolded portion of an orogen. Syn: downbuckle tectogenesis See: orogeny tectonic Said of or pertaining to the forces involved in, or the resulting structures or features of, tectonics. Syn: geotectonic tectonic breccia A breccia formed as a result of crustal movements, usually developed from brittle rocks. CF: fault breccia; fold breccia; crush breccia. AGI tectonic conglomerate See: crush conglomerate tectonic gap See: lag fault tectonic map A map that portrays the architecture of the outer part of the Earth. It is similar to a structure-contour map, which primarily shows dipping strata, folds, faults, and the like, but the tectonic map also presents some indication of the ages and kinds of rocks from which the structures were made, as well as their historical development. AGI 3245

tectonics A branch of geology dealing with the broad architecture of the outer part of the Earth; i.e., the regional assembling of structural or deformational features, a study of their mutual relations, origin, and historical evolution. It is closely related to structural geology, with which the distinctions are blurred, but tectonics generally deals with larger features. Adj: tectonic. Syn: geotectonics tectonism See: diastrophism tectonite Any rock whose fabric reflects the history of its deformation; a rock whose fabric clearly displays coordinated geometric features that indicate continuous solid flow during formation (Turner and Weiss, 1963). Also spelled tektonite. AGI tectonometer A radar apparatus that detects changes in rock structure, particularly faults. Nelson tectonophysicist One who studies clastic deformation, flow, and rupture of constituent materials of the Earth's crust and mantle to make deductions concerning the forces causing these deformations (changes). DOT tectonosphere The outer part of the Earth above the level of isostatic equilibrium, in which the dynamic processes are thought to occur that cause orogenesis near and at the surface. CF: crust tedge In founding, an ingate in a mold. Standard, 2 tee a. Eng. A crossvein meeting a main vein without intersecting it. b. A sleeve with a third opening in the side, usually at right angles, to allow a branch line to be connected to the main pipeline. Kentucky c. A fitting, either cast or wrought, that has one side outlet at right angles to the run. A single outlet branch pipe. Strock, 1 tee-beam 3246

A rolled steel section in the shape of the letter T, the flat top being the table. Hammond tee-bolt See: T-bolt teem To pour molten metal from a ladle into ingot molds. The term applies particularly to the specific operation of pouring either iron or steel into ingot molds. Also called teeming. ASM, 1 teemer a. A pourer of metal. Standard, 2 b. One who controls the rate of pouring (teeming) stainless steel into molds. DOT c. The person who teems or casts the pot of glass. See also: casting ASTM teeming a. Shaping glass by pouring it into or on molds, tables, or rolls. b. See: casting teeming trough Lanc. A cistern (or trough) into which the water is pumped from a mine. Fay teepleite a. A tetragonal mineral, Na2 B(OH)4 Cl . b. See: burkeite; gauslinite. From Borax Lake, CA. English teeter a. Dancing or boiling movement of small particles in a rising fluid column, when the velocity is too high to let them fall and too low to sweep them clear. Characteristic zone in hydraulic classifiers. Pryor, 3 b. The condition of a suspension of solids in an upward-moving current of water or air, whereby the support given to the particles reduces the internal friction between them to such an extent that the suspension acquires fluid or partially fluid properties. BS, 5 teineite An orthorhombic mineral, CuTeO3 .2H2 O ; blue; at the Teine Mine, Japan. tekoretin 3247

Fossil hydrocarbon similar to fichtelite. Tomkeieff tektite Glass spheroid, often with aerodynamic shape, found in strewn fields and associated with impact craters; each cluster of tektites is named for its locality, such as moldavites and australites. A tektite has been shaped by flight through the atmosphere while chilling and ablating and melted by meteorite impact. See also: water chrysolite tektonite See: tectonite telain a. Anglicized from the German telit. Greater fragments of plant tissues, which are completely soaked with vitrain; i.e., the cell walls as well as the cell cavities. AGI b. Used in the names of transitional coal lithotypes, e.g., clarotelain. AGI telegraph A vertical rectangular timber or steel chute for the transfer of coal to a lower level. Strips of wood placed crosswise in the chute retard the downward flow, and the chute is kept full for the same purpose. Nelson telemagmatic Said of a hydrothermal mineral deposit located far from its magmatic source. CF: apomagmatic; cryptomagmatic. See also: telethermal AGI telemeter rod A leveling staff used in connection with stadia work. See also: stadia rod teleoperation The remote manual operation of equipment that is usually not within the direct eyesight of the operator, yet the operator requires and is provided with sensory information (sight, sound, accelerations, etc.) for effective manual control. telephoto lens A combination of positive and negative lenses designed to obtain larger magnification of distant objects than is possible with ordinary lenses. Seelye, 2 3248

telescopic derrick A drill derrick divided into two or more sections, made so that the uppermost sections nest successively into the lower sections. In use, the sections are extended and locked into place to form a tall derrick and when moved are nested to form a unit length transportable on a single truck. Long telescopic drill rig A mobile electric, hydraulic, four-drill rig for boring blasting holes in quarries and opencast pits. All drills, percussive and rotary, can be simultaneously or independently raised, lowered, or slewed, enabling the rig to serve a working face 32 ft (9.8 m) high and 24 ft (7.3 m) wide. Nelson telescopic loading trough A shaker conveyor trough of two sections, one nested in the other, used near the face for advancing the trough line without the necessity of adding either a standard or a short length of pan after each cut. C-clamps hold the two sections together in any desired length. Jones, 1 telescopic section That section of a rigid side-framed conveyor that is (1) adjustable in length, (2) immediately adjacent to the tail section, and (3) so designed that it forms a continuous framing and cover for the return belt when the tail section is pulled back to tension the belt. NEMA, 2 telescoping conveyor A type of conveyor, the length of which may be varied by telescoping frame members. See also: extendable conveyor telethermal Said of a hydrothermal mineral deposit formed at shallow depth and relatively low temperatures, with little or no wall-rock alteration, presumably far from the source of hydrothermal solutions. Also, said of that environment. See also: telemagmatic mesothermal; epithermal; xenothermal; leptothermal. AGI telinite a. This term was proposed by W.J. Jongmans (1935) to designate a vitrinite showing cellular structure. The Nomenclature Subcommittee of the International Committee for Coal Petrology decided in 1957 to use the term telinite only for the cell walls seen in 3249

vitrinite. Only in this manner can telinite be rightly included among the macerals. Telinite shows more or less clearly defined cell structure (wood, periderm, etc.) sometimes deformed. The cells are generally filled with collinite, but the structure is better shown when the cells are either empty or filled by material such as resinite, fine micrinite, clay minerals, etc. IHCP b. A maceral of coal within the vitrinite group, characteristic of vitrain and consisting of cell-wall material. CF: suberinite; xylinite. AGI teller See: tab telltale a. A simple device for indicating selected conditions of loading, flow, direction, etc. Pryor, 3 b. A device for keeping a check on employees (as factory hands, drivers, check takers), esp. a time clock. Webster 3rd telluric bismuth A former name for tetradymite. See also: tetradymite telluric current Natural electric current that flows on or near the Earth's surface in large sheets. Syn: earth current telluric-current prospecting A geophysical prospecting technique utilizing natural Earth currents as a source instead of artificially generated currents injected into the ground. Dobrin telluric ocher The mineral tellurite, TeO2 . Fay telluric silver See: hessite telluride A mineral that is a compound of a metal and tellurium, such as hessite, Ag2 Te . tellurides 3250

Ores of the precious metals (chiefly gold) containing tellurium. Gordon telluriferous Yielding or containing tellurium. Standard, 2 tellurite An orthorhombic mineral, TeO2 ; dimorphous with paratellurite; colorless to yellow; occurs in hydrothermal veins. tellurium A trigonal mineral, Te , native tellurium; soft; sp gr, 6.2; semimetallic; in pyrite, sulfur, or in the fine dust of gold-telluride mines. tellurium glance See: nagyagite tellurium mineral Primarily native tellurium, Te ; tellurite, TeO2 ; tetradymite, Bi2 Te2 S ; or hessite, Ag2 Te . tellurnickel See: melonite tellurobismuthite A trigonal mineral, Bi2 Te3 ; tetradymite group; forms a series with tellurantimony. tellurometer Trade name of a rugged portable electronic device that measures ground distances precisely by determining the velocity of a phase-modulated, continuous, microwave radio signal transmitted between two instruments operating alternately as master station and remote station. It has a range up to 35 to 40 miles (56 to 64 km). CF: geodimeter telpher An electric hoist that hangs from a power-driven wheeled cab rolling on an overhead rail; it is often referred to as a monorail. See also: aerial ropeway 3251

telpherage Automatic aerial transportation, as by the aid of electricity, esp. that system in which the carriages having independent motors are run on a stout wire conducting an electric current. Standard, 2 Telsmith breaker A type of gyratory crusher often used for primary crushing. It has a fixed spindle; i.e., the spindle is not suspended from above, but is mounted in a long eccentric sleeve. Rotation of the sleeve imparts a gyratory motion to the crushing head, but gives a parallel stroke; i.e., the axis of the spindle describes a cylinder rather than a cone as in the suspended spindle gyratory. Adjustment for set in the Telsmith breaker is accomplished by placing shims between the bottom of the breaking head and an adjusting plate--the addition of shims at this point raises the crushing head and increases the throat opening. Newton, 1; Newton, 2 Telsmith gyrasphere A type of secondary crusher that utilizes the gyratory principle; it has a hemispherical crushing head. Newton, 1 temblor See: earthquake temiskamite See: maucherite temperature a. The heat content of a body as measured on a definite scale based on some observable phenomenon; e.g., the expansion of mercury on heating. See also: absolute temperature; Celsius; centigrade; critical temperature; Fahrenheit; Kelvin temperature scale; Rankine scale. Webster 3rd b. A degree of hotness or of coldness measured on one of several arbitrary scales based on some observable phenomenon; e.g., the expansion of mercury on heating. The degree of a material substance that is a linear function of the kinetic energy of the random motion of its molecules. The degree of a vacuum that depends upon the density of the radiant energy within it. Abbreviations and symbols, temp; T; t; T; t. CF: absolute zero Webster 3rd temperature coefficient

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A numerical value indicating the relation between a change in temperature and a simultaneous change in some other property (e.g., solubility). Specif., the factor a in the equation Rt = R0 (1 at), in which Rt equals the resistance of a conductor at t degrees C, and R 0 equals its resistance at 0 degrees C. Syn: positive temperature coefficient temperature colors Colors shown to the eye by incandescent bodies at different temperatures. temperature dew point Temperature at which condensation of water occurs; a saturation temperature. Hartman, 2 temperature gradient a. The rate of change of temperature with distance in a specified direction. Also called lapse rate. AGI b. A curve showing the temperature at different distances from the hot face, in a refractory wall. temperature logging The measurement of temperature in boreholes by use of a delicate thermometer that will record temperature anomalies of as much as 7 degrees F (3.9 degrees C) for thin coal seams in coal measures according to the thermal conductivity of the rocks concerned. Sinclair, 3 temperature profile recorder A portable unit consisting of a thermistor sensing element, 6-V power supply, amplifier, and recorder. The recorder is geared to a drum containing an electrical cable to which the bead is fastened. When the bead is lowered into the water, the paper on the recorder is moved accordingly. Depth is measured by the amount of wire paid out. This device is used in shallow water, particularly in lakes. Hunt temperature-regulating equipment Any equipment used for heating and cooling the rectifier together with the devices for controlling and indicating its temperature. Coal Age, 1 temperature standards For normal measurement, 0 degrees C (regarding gas properties). For thermodynamics and physical properties, either 18 degrees C or 25 degrees C, as defined in each stated case. Pryor, 3 3253

temperature steel Reinforcement introduced into a concrete slab or other member to minimize any cracks arising from shrinkage or from temperature stresses. Hammond temperature stress Stress in a structural member due to a rise or fall of temperature. See also: temperature steel temperature survey a. A geophysical prospecting method that measures either (1) temperature anomalies in boreholes or (2) temperature trends and concentrations along the ground surface. For example, a temperature survey across a salt dome may give peak values in the central area, due to the high thermal conductivity of the buried salt mass. See also: temperature logging Nelson b. Measurement of temperature in drill holes. An absolute accuracy of about 0.05 degrees C and a precision of about 0.005 degrees C can be obtained. Maps of isotherm surfaces can be constructed that help to detect anomalies in geologic structure or subsurface ground-water conditions. AGI tempered In brickmaking, (1) moistened and worked to the proper consistency, as clay for bricks or molding, and (2) capable of being cut with ease, as bricks made of such clay. Standard, 2 tempered steel Steel that has been hardened and subsequently tempered by a second lower heating. Fay temperer One who or that which tempers; specif., a machine for mingling and thoroughly working potter's clay, brick clay, mortar, plaster, or other materials. Standard, 2 temper hardening A term applied to alloys that increase in hardness when heated after rapid cooling; also to the operation of producing this. Also called artificial aging; distinguished from aging or age hardening, which occurs at atmospheric temperature. Both processes are covered by the term precipitation hardening. CTD tempering bar 3254

See: furgen tempering furnace A furnace for heating articles in the process of tempering. Standard, 2 tempering machine A machine for giving large steel plates a uniform and thorough tempering without permitting them to bend or buckle; usually by pressing them between hot masses of iron, or by firmly clamping them between jaws or plates while immersing them in a tempering bath. Standard, 2 tempering oven An oven for heating glass in the process of annealing; a leer. Standard, 2 template a. A form for building tunnel inverts. Stauffer b. A pattern device used as a guide to mark points at which boreholes are to be collared in ring drilling. Long temporary adjustment An adjustment, such as leveling or focusing, made to a surveying instrument at each setup. See also: permanent adjustment Hammond temporary hardness See: carbonate hardness temporary hardness of water The carbonate component of water hardness, which can be destroyed by boiling. See also: hard water temporary roof support In coal mining; during roof bolting process, vertical posts are installed tight with wedges near the area where the next roof bolt will be installed. These are installed by reaching from a bolted area of the roof. Installed to support potentially loose roof to prevent fall onto persons. temporary shaft support 3255

A timber or steel lining inserted for a limited period until a permanent shaft support is installed. See also: skeleton tubbing temporary splice According to the Federal Coal Mine Safety Act, a temporary splice is one that does not have a rubber or neoprene jacket vulcanized over the splice and bonded to the cable jacket. USBM, 3 tenacity a. The property of the particles or molecules of a substance to resist separation; tensile strength. AGI b. The force of strength with which the particles (or molecules) of a mineral or rock hold together or resist separation. The terms commonly used to describe the tenacity of a mineral are friable, brittle, sectile, malleable, flexible, elastic, and tough. Stokes tender a. Said of roof shale that tends to break up or crush under pressure into small fragments and that will not hold in any span over a few inches. Also called short. Raistrick b. The formal offer by the tenderer to carry out the work described in the drawings and/or specification for a certain sum of money. See also: agreement tennantite An isometric mineral, (Cu,Fe)12 As4 S13 ; tetrahedrite group; forms a series with tetrahedrite; may contain zinc, silver, or cobalt replacing copper; in veins; an important source of copper. Syn: gray copper ore tenon A projecting tongue fitting into a corresponding cavity called a mortise. Fay tenor See: grade tenorite A monoclinic mineral, CuO ; occurs in gray scales, black powder, or earthy masses; sp gr, 6.4; in oxidized zones of copper deposits; a source of copper. Syn: melaconite; black copper. See also: black copper ore tensile force 3256

A force such as the force applied when a haulage rope pulls a set of tubs. Morris tensile strength The maximum applied tensile stress that a body can withstand before failure occurs. Syn: tenacity AGI tensile stress A normal stress that tends to cause separation across the plane on which it acts. CF: compressive stress tensile test A test in which material is subjected to an increasing tensile pull until it fractures. A stress-strain curve may be plotted, and the limit of proportionality, proof stress, yield point, ultimate tensile stress, elongation, and reduction in area can be determined. CTD tension a. In subsidence, the amount of lengthening per unit of measurement. Nelson b. In engineering, a pulling force or stress; metals in tension are strong, while concrete and masonry are weak. Nelson c. A system of forces tending to draw apart the parts of a body, esp. of a belt, a line, a cord, or a sheet, combined with an equal and opposite system of resisting forces of cohesion holding the parts of the body together. The stress caused by pulling; opposite of compression and distinguished from torsion. Standard, 2 d. Sometimes used in place of voltage or electromotive force. See also: tension zone tension carriage A bogie or frame carrying a pulley around which the rope of an endless rope haulage passes to be tensioned or tightened. The bogie moves on rails and may be kept taut by balance weights or placed on an inclined roadway (with sufficient weights) to move up or down according to the tension in the endless rope. A tension device is necessary to take up any slack rope created by varying loads on the haulage system. Nelson tension-control cylinder A hydraulic piston and cylinder mechanism that can be attached to a rotary-drill feedoff line and adjusted to allow the drill stem to feed downward while maintaining a constant preset tension on the drill string. See also: tension drilling tension correction

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The correction that must be applied to a tape if it is being used at a tension different from that at which it was standardized. See also: tape corrections tension drilling Drilling with part of the weight of the drill string supported by the drill swivel head or suspended on a drilling line, as opposed to drilling with the entire weight of the string imposed on the bit. See also: tension-control cylinder; weight indicator. Long tension end The tail end or receiving end of a belt conveyor. It consists of a return drum carried in a boxlike structure. A scraper, plow, or brush is attached to remove as much as possible of the spillage on the bottom belt before it passes on to the return drum. The tension end is drawn back by two sylvesters attached to staking anchor props; this enables adequate, but not excessive, tension to be imparted to the belt. See also: sylvester; tailend. Sinclair, 5 tension fault a. A generic term for any fault caused by tension. AGI b. Geological fault due to tension, which separates rock strata; unlike gravity or normal fault, since strata may reappear on other side of gap caused by fall of intervening section to lower level when fissure opened. Pryor, 3 tension flange The side of a beam in tension, being the lower side in the general case of a simple beam supported at both ends. Hammond tension fracture a. A fracture that is the result of tensional stress in a rock. CF: shear fracture AGI b. A fracture that is the result of stresses that tend to pull material apart. Billings c. See: subsidiary fracture tension jack A type of jack equipped with a jackscrew for wedging against the roof, which also has a ratchet device for applying tension on a chain to be attached to the tail or foot section of a belt conveyor. The jacks and tension chains pull the tail section back until the belt is at the proper tension. Jones, 1 tension joint 3258

A joint that is a tension fracture. Syn: cross joint; tension fracture. tension linkage A chain application in which linear motion is not continuous in direction. Jackson, 1 tension zone The surface area affected by tensile strain. CF: compression zone; neutral zone; tension. Nelson tepee butte A conical hill or knoll resembling a Native American tepee; esp. an isolated, residual hill formed by a capping of resistant rock that protects the underlying softer material from erosion. Also spelled: teepee butte. AGI tepetate a. An evaporite consisting of a calcareous crust coating solid rocks on or just beneath the surface of an arid or semiarid region; a deposit of caliche. AGI b. Mex. A volcanic tuff, or a secondary volcanic or chemical nonmarine deposit, very commonly calcareous. Etymol. Mexican Sp., from Nahuatl (Aztec) tepetatl, stone matting. AGI tephra A general term for all pyroclastics of a volcano. AGI tephrite A group of extrusive rocks, of basaltic character, primarily composed of calcic plagioclase, augite, and nepheline or leucite as the main feldspathoids, with accessory alkali feldspar; also, any member of that group; the extrusive equivalent of theralite. With the addition of olivine, the rock would be called a basanite. AGI tephritoid Said of a rock resembling tephrite. tepla-masse A coal-tar pitch, for protecting the outside of steel tubes against corrosion and bacteria. Osborne terlinguaite 3259

A monoclinic mineral, Hg2 ClO ; yellow; at Terlingua, TX. terminal curvature A sharp, local change in the dip of strata or cleavage near a fault. Not commonly used in the United States. CF: drag terminal velocity The constant velocity acquired by a particle falling in water or air when the frictional resistance is equal to the gravitational pull. See also: equal-falling particles; Stokes' law. Nelson termination In mineralogy, the end of a crystal, esp. crystal faces that intercept the crystallographic axis, as distinguished from a broken or polished end. Crystals are singly terminated if faces appear on one end as in attached crystals or ones lacking the symmetry to require faces on both ends to complete a crystal form; they are doubly terminated if faces appear on both ends. terms of reference Schedule that defines responsibilities and area of activity delegated to and/or accepted by subsection, department, or subordinate official in organization working on line-and-staff system of large company where harmonious cooperation might otherwise be endangered. Pryor, 3 ternary a. A phase system that may be defined in terms of three components. b. Any phase in a ternary system consisting of all three components. c. A eutectic, peritectic, or other singular point in a ternary system. ternary steel An alloy steel that contains one alloying element; the term is synonymous with a simple alloy steel. It contains the one element plus the iron and carbon, hence ternary. Fay terne Sheet iron or steel coated with an alloy of about four parts lead to one part tin. Webster 3rd terneplate 3260

Sheet steel covered with a tin-lead alloy. Terni furnace A modification of the open-hearth furnace in which the essential feature is the port design. The air ports gradually increase in cross section until they are as large as the hearth itself, thus practically eliminating turbulent flow in the furnace. Osborne terosin See: fichtelite terpene Hydrocarbon present (30% to 60%) in pine oil, which is widely used as frother in the flotation process. Pryor, 3 terpineol The principal frothing agent in pine oil. Pryor, 3 terra alba a. Finely pulverized powder, CaSO4 .2H2 O , made from gypsum and used in the manufacture of paper, paints, artificial marble, and composition plastics. CCD, 2 b. Any of several white mineral substances, such as (1) gypsum ground for a pigment; (2) kaolin used esp. as an adulterant of paints; (3) burnt alum; (4) magnesia; and (5) blanc fixe. Webster 3rd terrace a. A level or nearly level plain, generally narrow in comparison with its length, from which the surface slopes upward on one side and downward on the other side. Terraces and their bounding slopes are formed in a variety of ways, some being aggradational and others degradational. Fay b. A flaw in marble, commonly cored out and filled up. Webster 2nd c. A raised portion of an ancient riverbed or a bank on which alluvial deposits may be found. Nelson d. A bench in quarry or opencast mining. Nelson e. A ridge, a ridge and hollow, or a flat bench built along a ground contour. Nichols, 1 f. A narrow, gently sloping constructional coastal strip extending seaward or lakeward, and veneered by a sedimentary deposit; esp. a wave-built terrace. AGI g. Loosely, a stripped wave-cut platform that has been exposed by uplift or by lowering of the water level; an elevated wave-cut bench. AGI h. Any long, narrow, relatively level or gently inclined surface, generally less broad than a plain, bounded along one edge by a steeper descending slope and along the other by a steeper ascending slope; a large bench or steplike ledge breaking the continuity of a slope. The term is usually applied to both the 3261

lower or front slope (the riser) and the flattish surface (the tread), and it commonly denotes a valley-contained, aggradational form composed of unconsolidated material as contrasted with a bench eroded in solid rock. A terrace commonly occurs along the margin and above the level of a body of water, marking a former water level; e.g., a stream terrace. AGI i. A term commonly but incorrectly applied to the deposit underlying the tread and riser of a terrace, esp. the alluvium of a stream terrace; this deposit should more properly be referred to as a fill, alluvial fill, or alluvial deposit, in order to differentiate it from the topographic form. AGI j. See: structural terrace terrace placer See: bench placer terra cotta clay A term applied loosely to any fine-textured, fairly plastic clay that acquires a natural vitreous skin in burning and that is used in the manufacture of terra cotta. It is characterized by low shrinkage, freedom from warping, strong bonding, and absence of soluble salts. AGI terra-cotta model maker One who makes metal profiles and wooden forms for use in casting plaster terra-cotta block mold. DOT terrain A tract or region of the Earth's surface considered as a physical feature, an ecologic environment, or a site of some planned human activity, e.g., an engineering location; or in terms of military science, as in terrain analysis. Not to be confused with terrane. AGI terrain coefficient A terrain coefficient is a number expressing the ratio of actual ground displacement by elastic waves to that which the same waves would produce in rock. The terrain coefficient for rock is thus 1; for unconsolidated materials it ranges upward to as high as 30, depending on the thickness of the material. Leet, 2 terrain correction A correction applied to observed values obtained in geophysical surveys in order to remove the effect of variations in the observations due to the topography near observation sites. Syn: topographic correction AGI terrain slope 3262

Used to describe quarries when located in low slopes. CF: hillside Streefkerk terrane a. A group of strata, a zone, or a series of rocks; used in the description of rocks in a general, provisional, or noncommittal sense. Fay b. A region considered in relation to its fitness for some purpose; an extent of ground or territory. Standard, 2 c. A faultbounded body of rock of regional extent, characterized by a geologic history different from that of contiguous terranes. A terrane is generally considered to be a discrete allochthonous fragment of oceanic or continental material added to a craton at an active margin by accretion. See also: suspect terrane d. Informally, a region where a particular rock or group of rocks predominates. Not to be confused with terrain. AGI terra ponderosa Literally, heavy earth; another name for heavy spar or barite. Fay terra rossa A reddish-brown residual soil found as a mantle over limestone bedrock, typically in the karst areas around the Adriatic Sea, under conditions of Mediterranean-type climate. Also spelled: terra rosa. Etymol: Italian, red earth. AGI terras In marble working, a defective or disfigured place in a marble block, which is cut out and filled with a composition. Also spelled terrace. Standard, 2; Fay terra sienna See: ocher terra silicea See: infusorial earth terrazzo Small chips or pieces of stone, usually marble or limestone, about 1/2 to 3/4 in (1.3 to 1.9 cm) in diameter, made by crushing and screening. Terrazzo chips are used with portland cement in making floors, which are smoothed down and polished after the cement has hardened. USBM, 6 terrestrial 3263

a. Pertaining to the Earth. AGI b. Pertaining to the Earth's dry land. AGI terrestrial deposit a. A sedimentary deposit laid down on land above tidal reach, as opposed to a marine deposit, and including sediments resulting from the activity of glaciers, wind, rainwash, or streams; e.g., a lake deposit, or a continental deposit. AGI b. Strictly, a sedimentary deposit laid down on land, as opposed to one resulting from the action of water; e.g., a glacial or eolian deposit. AGI c. A sedimentary deposit formed by springs or by underground water in rock cavities. CF: terrigenous deposit terrestrial magnetism The natural magnetic field within and surrounding the Earth and the factors affecting it. Hy terre verte a. Fr. "green earth". Glauconite or other phyllosilicate used as artist's pigment. b. Collective name for various pale bluish-green earths formed by the disintegration of minerals, principally those of the hornblende type. Also called green earth. terrigenous Derived from the land or continent. AGI terrigenous deposit Shallow marine sediment consisting of material eroded from the land surface. CF: terrestrial deposit terrigenous sediments Sediments derived from the destruction of preexisting rocks on the Earth's surface, as distinguished, e.g., from sediments of organic or volcanic origin. Stokes territe A plastic explosive that consists of the constituents blasting gelatin+BNT+sodium nitrate+ammonium perchlorate. The explosive has a relatively low rate of detonation and is very insensitive, on which account care must be taken to ensure that its initiation is extremely powerful. Fraenkel territorial sea 3264

A belt of sea, not exceeding 12 nmi (22.2 km) in breadth, lying beyond its land territory and internal waters and, in the case of an archipelagic State, its archipelagic waters, in which a coastal State has sovereignty. United Nations terroite An extra-strong high explosive of the nitroglycerin type. Standard, 2 Tertiary The first period of the Cenozoic Era (after the Cretaceous of the Mesozoic Era and before the Quaternary), thought to have covered the span of time between 65 million years and 3 to 2 million years ago. It is divided into five epochs: the Paleocene, Eocene, Oligocene, Miocene, and Pliocene. It was originally designated an era rather than a period; in this sense, it may be considered to have either five periods (Paleocene, Eocene, Oligocene, Miocene, Pliocene) or two (Paleogene and Neogene), with the Pleistocene and Holocene included in the Neogene. AGI tertiary crushing The preliminary breaking down of run-of-mine ore and sometimes coal. In metal mines, the tertiary crushing may be performed at a central point underground. See also: primary breaker tertiary grinding When a particularly fine grinding of ore is needed, two and even three ball mills may be used in a series to attain the degree of fineness. The successive stages are referred to as primary, secondary, and tertiary grinding. Newton, 1 tertiary shaft The shaft that extends a mine downward from the bottom of the secondary shaft. Spalding tervalent Having three different valences. Syn: trivalent tessellated a. A surface divided into squares, or figures approaching squares, by joints or natural divisions. Fay b. Composed of tesserae--small cubes of stone, marble, glass, or terra cotta variously colored and arranged in artistic design: inlaid; mosaic; as tessellated pavement. Standard, 2 3265

tesseral In crystallography, the same as isometric. Standard, 2 test a. To search for mineral deposits in an unproved area by means of boreholes. b. To obtain samples of soil or rock from which the physical characteristics of the soil or rock can be determined, such as in foundation testing. c. An exploratory borehole. test bore Drilling to test subsoil and rocks when considering foundations of buildings, dams, and heavy plant. Pryor, 3 test boring As used by foundation engineers, the act or process of sinking holes into the overburden (sometimes to considerable depth into bedrock) with rotary or drive sampling equipment for the purpose of recovering samples from which information on the physical characteristics of the materials penetrated can be obtained; also applied to the sample or samples so obtained. Syn: borehole; drill hole; drilling. Long test core Core removed from a concrete structure by diamond core drilling and tested in a laboratory to determine the strength and other physical properties of the concrete. Also, core removed from a borehole drilled in search of oil and used to determine the porosity of the core and whether oil is present. Long test detonator An instantaneous detonator that has a strength equivalent to that of a detonator with a base charge of 0.40 to 0.45 g PETN. CFR, 4 tester a. A sampling instrument. Nelson b. A person responsible for carrying out ventilation, dust, or other tests. Nelson c. Service company representative who supervises borehole testing operations. Wheeler, R.R. test hole a. Generally, any borehole drilled to obtain samples whereby the structural and physical characteristics of the rocks penetrated can be determined; more specif., a hole produced 3266

by rotary or driving soil-testing tools in the course of obtaining samples used in soil- and foundation-testing work. Long b. Usually a small hole drilled ahead and flanking in a working place to ascertain proximity of old workings and to determine water or air content of same. BCI c. A drill hole or shallow excavation for testing an orebody; a test pit. Fay d. A taphole, as in a cementation furnace. Standard, 2 testing bedrock See: bedrock test testing flame The lowered flame of a miner's flame safety lamp, which is used to detect the presence of small percentages of combustible gases in mine air. Nelson testing machine A machine used for applying test loads to standard test pieces or to structural members. Machines are available for carrying out tensile, compressive, impact, and fatigue tests. Hammond test lead Lead free from any silver, and often finely granulated; used in testing or cupelling, assaying, etc. Webster 3rd test paper Paper (as litmus paper) cut usually in strips and saturated with an indicator or other reagent that changes color in testing for various substances. Webster 3rd test piece A piece of material prepared in a suitable shape so that it can be tested in a testing machine. Hammond test pit a. A shallow shaft or excavation made to determine the existence, extent, or grade of a mineral deposit, or to determine the fitness of an area for engineering works, such as buildings or bridges. Stokes b. See: test hole; trial pit. test ring An oval iron frame for holding a test or movable cupelling hearth. Fay 3267

test stone Basanite. Used for testing streak of precious metals. tetartohedral Said of a point group or of specific crystal forms in the isometric and tetragonal crystal systems that have but one-fourth the crystal faces generated for the equivalent crystal form in the holohedral (most symmetric) crystal class. These complimentary merohedral forms are designated plus or minus and left or right, four forms being required to show all the faces of the holohedral form because each form lacks both a center and mirror planes of symmetry. See also: merohedral tetraboron carbide See: boron carbide tetrad A crystallographic axis of rotation of 90 degrees , four-fold. CF: axis of symmetry tetradymite a. A trigonal mineral, Bi2 Te2 S ; forms foliated masses in auriferous veins, commonly with tellurobismuthite; a source of bismuth. Syn: telluric bismuth; bismuth telluride. b. The mineral group kawazulite, paraguanajuatite, skippenite, tellurantimony, tellurobismuthite, and tetradymite. tetraethyllead An antiknock constituent of gasoline; Pb (C2 H5 )4 . tetragonal a. Designating or belonging to a system of crystallization having all three axes at right angles and the two lateral axes equal. This system is called tetragonal system. Fay b. The crystal system in which crystals have one four-fold symmetry axis. Hurlbut c. The crystal system characterized by three orthogonal crystallographic axes, the principal or c axis being a tetrad (4-fold axis), longer or shorter than the two lateral a axes. See also: crystal systems tetragonal trisoctahedron See: trapezohedron 3268

tetrahedral Having the symmetry or shape of a tetrahedron. tetrahedrite a. An isometric mineral, (Cu,Fe)12 Sb4 S13 , having copper replaced by zinc, lead, mercury, cobalt, nickel, or silver; forms a series with tennantite and freibergite; metallic; crystallizes in tetrahedra; occurs in hydrothermal veins and contact metamorphic deposits; a source of copper and other metals. Syn: gray copper ore; gray copper; panabase; panabasite; stylotypite. b. The mineral group freibergite, giraudite, goldfieldite, hakite, tennantite, and tetrahedrite. tetrahedron An isometric crystal form of four faces, each an equilateral triangle; the alternate faces of an octahedron. Adj: tetrahedral. tetrahexahedron An isometric crystal form (hk0) of 24 faces, each an isosceles triangle, so arranged that four faces appear to replace each face of a cube (hexahedron). tetravalence An atom, or group, having four valence bonds. Pryor, 3 tetravalent a. Having a valence of 4. Webster 3rd b. Having four valences; e.g., chlorine, which has valences of 1, 3, 5, and 7. Webster 2nd; Handbook of Chemistry and Physics, 2 tewel a. A hole; bore; a chimney, as for smoke. Webster 3rd b. The tuyere of a furnace. Webster 2nd texture The general physical appearance or character of a rock, including the geometric aspects of, and the mutual relations among, its component particles or crystals; e.g., the size, shape, and arrangement of the constituent elements of a sedimentary rock, or the crystallinity, granularity, and fabric of the constituent elements of an igneous rock. The term is applied to the smaller (megascopic or microscopic) features as seen on a smooth surface of a homogeneous rock or mineral aggregate. The term structure is generally 3269

used for the larger features of a rock. The two terms should not be used synonymously, although certain textural features may parallel major structural features. Confusion may arise because in some languages, e.g., French, the usage of texture and structure are the reverse of the English usage. CF: structure AGI thalenite A monoclinic mineral, Y3 Si3 O10 (OH)(?) ; red to pink; in pegmatites. thallium A metallic element resembling lead in physical properties; the metal is silvery-white, but turns bluish-gray in air. Symbol, Tl. Occurs in crooksite, lorandite, and hutchinsonite. It is also present in pyrites and is recovered from the roasting of this ore in the manufacture of sulfuric acid and from the smelting of lead and zinc ores. Used in low-melting glasses, photocells, and infrared detectors. Handbook of Chemistry and Physics, 3 thalweg a. The line of continuous maximum descent from any point on a land surface; e.g., the line of greatest slope along a valley floor, or the line crossing all contour lines at right angles, or the line connecting the lowest points along the bed of a stream. Etymol: German Talweg, valley way. Also spelled: talweg. AGI b. In physical geography, a term adopted into English usage signifying the line of greatest slope along the bottom of a valley; i.e., a line drawn through the lowest points of a valley in its downward slope. It thus marks the natural direction of a watercourse. AGI c. In hydraulics, the line joining the deepest points of a stream channel. AGI d. By many geomorphologists, the term is used as a syn. for valley profile. AGI e. The center line of the principal navigational channel of a waterway constituting a boundary between political subdivisions. Hunt thanite a. A mixture of kainite and halite. English b. Carbon oxysulfide, COS, as a natural gas. thaumasite A hexagonal mineral, Ca6 Si2 (CO3 )2 (SO4 )2 (OH)12 .24H2 O ; white; fibrous. thaw house A small building, designed for thawing dynamite, of such size as to provide enough thawed dynamite for a day's work. Fay thawing 3270

a. A method of working permanently frozen ground in which water at a temperature of from 50 to 60 degrees F (10 to 15.6 degrees C) is pumped through pipes down into the frozen gravel. The pipes through which the water is pumped are called sweaters. See also: steam thawing; thaw pipe. Lewis b. In dynamiting, warming to reduce risk of premature explosion that might originate from rupture of frozen crystal. Performed in thaw house or thawing kettle using steam or hot water. With modern methods of explosive manufacture, the need has practically disappeared. Pryor, 3 thawing kettle A double kettle, built somewhat like a farina boiler, having two compartments, an outer compartment, which is filled with hot water and which entirely surrounds the inner compartment that contains the dynamite to be thawed. It is provided with a lid for retaining the heat. Fay thaw pipe A string of pipe lowered into a string of drill rods that is frozen in a borehole drilled into permafrost, through which water is circulated to thaw the ice and free the drill rods. See also: thawing thaw shed operator In the coke products industry, one who thaws frozen materials in railroad cars by heating sections of shed where cars are spotted. DOT THDM See: translucent humic degradation matter thelotite A carbonaceous constituent of torbanite, occurring in the form of a solidified clear, jellylike substance, something like solidified dopplerite, but probably of unlike chemical composition. Tomkeieff thematic mapper A cross-track scanner deployed on Landsat that records seven bands of data from the visible through the thermal IR regions. See: multispectral scanner thenardite An orthorhombic mineral, Na2 SO4 ; soft; forms masses and crusts in evaporite deposits and around fumaroles; a source of sodium sulfate. Also called verde salt. 3271

theodolite A precision surveying instrument that is used for measuring angular distances in both vertical and horizontal planes. theoretical depression The water gage produced by an imaginary fan that is perfect and is connected to an evase chimney of infinite height to eliminate kinetic losses at discharge. Its calculated value depends only on the speed of the blade tips and on the shape of the blades. See also: manometric efficiency; initial depression. Nelson theoretical fan depression The depression that can be produced by a perfect fan. BS, 8 theoretical tonnage See: probable reserves theoretical yield The maximum yield (as shown by the washability curve) of a product with a specified percentage of ash. BS, 5 theory of lateral secretion The theory that the contents of a vein or lode are derived from the adjacent country rock by a leaching process, in which either superficial water or thermal water is involved. theory of machines Comprises the study of the relative motion between the parts of a machine and the study of the forces that act on those parts. See also: machine design theralite A group of mafic plutonic rocks composed of calcic plagioclase, feldspathoids, and augite, with lesser amounts of sodic sanidine and sodic amphiboles and accessory olivine; also, any rock in that group; the intrusive equivalent of tephrite. Theralite grades into nepheline monzonite with an increase in the alkali feldspar content, into gabbro as the feldspathoid content diminishes, and into diorite with both fewer feldspathoids and increasingly sodic plagioclase. The term, defined by Rosenbusch in 1887, is derived from the Greek word for eagerly looked for, not from the island of Thera (Santorini). AGI 3272

therm Equals 100,000 Btu (105,500 kJ). Newton, 1 thermal Hot or warm; applied to springs that discharge water heated by natural agencies. Fay thermal-acceptance ratio A physiological method of assessing the effect of a given climate upon workers, that is based on the ratio between the heat actually lost by the body via the skin, lungs, etc., and the maximum that can be lost in the prevailing conditions. Roberts, 1 thermal analysis a. A method for determining transformations in a metal by noting the temperatures at which thermal arrests occur. These arrests are manifested by changes in slope of the plotted or mechanically traced heating and cooling curves. ASM, 1 b. The study of chemical and/or physical changes in materials as a function of temperature, i.e., the heat evolved or absorbed during such changes. AGI thermal boring Use of high-temperature flame to fuse rock in drilling. Heat comes from ignition of kerosene with oxygen or other fuel system, at bottom of drill hole, and water with compressed air may be used to flush out the products. Pryor, 3 thermal capacity a. Heat required to raise the temperature of a body 1 degrees C. Syn: heat capacity b. The amount of heat that a clay product will absorb, usually expressed in British thermal units per degree Fahrenheit (kilojoules per degree Celsius). ACSG, 2 thermal conductivity a. The time rate of transfer of heat by conduction, through unit thickness, across unit area for unit difference of temperature. AGI b. A measure of the ability of a material to conduct heat. Typical values of thermal conductivity for rocks range from 3 to 15 mcal/cm/s/ degrees C (12.6 to 62.8 kJ/cm/s/ degrees C). Syn: heat conductivity; thermal diffusivity of strata. AGI thermal cutout

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A device fitted in hydraulic power systems underground so that temperatures cannot rise above about 85 degrees C. It is a safeguard against fire risk due to a rapid rise in temperature if the fluid circuit is interrupted by wrong manipulation of valves, etc. Nelson thermal diffusivity of strata See: thermal conductivity thermal drying a. The evaporation of water by thermal means from a mixture of coal and water. See also: McNally-Vissac dryer; multilouvre dryer; Raymond flash dryer; cascade coal dryer; flash coal dryer; fluidized bed dryer. Mitchell b. The application of heat (generally hot-air currents) to wet coals and other materials and the evaporation of the free moisture and also part of the inherent moisture. Nelson thermal efficiency The ratio of the electric power produced by a powerplant to the heat value of the fuel consumed; thus, a measure of the efficiency with which the plant converts thermal energy to electric energy. Symbol, eta . Lyman; Handbook of Chemistry and Physics, 2 thermal electromotive force The electromotive force generated in a circuit containing two dissimilar metals when one junction is at a different temperature from the other. ASM, 1 thermal emissivity The thermal emissivity, or heat transfer coefficient, of a rock surface is the rate at which heat will flow from rock to air, per unit area for 1 degree temperature difference. This varies with color and other surface characteristics. Measured in W/m2 .K. Roberts, 1 thermal expansion The increase in linear dimensions and volume that occurs when materials are heated and that is counterbalanced by a contraction of equal amount when the materials are cooled. Harbison-Walker thermal gradient In the Earth, the rate at which temperature increases with depth below the surface. In a mine, this is usually estimated at 5.3 degrees F/1,000 ft (1 degrees C/100 m) of shaft depth. Some variability with time of day is typically observed. SME, 1 3274

thermal metamorphism A type of metamorphism resulting in chemical reconstitution controlled by a temperature increase, and influenced to a lesser extent by confining pressure; there is no requirement of simultaneous deformation. See also: pyrometamorphism load metamorphism; static metamorphism. Syn: thermometamorphism AGI thermal precipitator An instrument for obtaining information regarding the number of particles present in unit volume of a dust cloud, together with their size distribution. This is probably the most efficient instrument used for dust counts since its efficiency is practically 100% for all particles from 0.2 to 10 mu m in diameter. See also: Hexhlet sampler; dust sampling. thermal probe A device used for measuring the heat flow out of ocean bottom sediment. Hunt thermal prospecting A system of geophysical prospecting based on measuring underground temperatures or temperature gradients and relating their irregularities to geological deformation. AGI thermal reactor A nuclear reactor in which the fission chain reaction is sustained primarily by thermal neutrons. Most reactors are thermal reactors. Lyman thermal-release water spray A device that brings water sprays into action when heating occurs on roadway belt conveyors. The local heat fuses an element holding taut wires. On release by fusion, the wires allow spray valves to open and the water cools the affected area. Nelson thermal resistance See: resistance thermal resistivity See: resistivity thermal separation

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The separation of minerals and metals by heat. The method is used, e.g., to remove impurities from rock salt. The crude salt is first exposed to radiant heat. The impurities absorb the heat and become warm, while the rock salt transmits the radiant heat and remains cool. The warm, impure particles adhere slightly to a belt covered with heatsensitive resin, while the salt remains free. Separation takes place at the end of the belt. The cool salt is thrown into one container, while the adhering impurities drop directly into another. Nelson thermal shock Failure of a material, esp. a brittle material, due to the thermal stress of rapidly rising or falling temperature. AGI thermal shock resistance The ability to withstand sudden heating, cooling, or both without cracking or spalling. thermal spalling The chipping or spalling of ceramic ware by repeated heating and cooling. thermal spring A spring whose water temperature is appreciably higher than the local mean annual atmospheric temperature. AGI thermal value (volatile matter) The calorific value of volatile matter in therms per ton of dry coke, of the gas given off when dry coke, ground to pass a 36-mesh B.S. test sieve, is heated under standard conditions. BS, 1 thermal water Water, generally of a spring or geyser, whose temperature is appreciably above the local mean annual air temperature. AGI thermic boring a. A method of boring holes in concrete under the high temperature generated by a burning steel tube, known as a lance. This is packed with steel wool, through which a jet of suitable gas flows to ignite the end of the lance and keep it burning. Hammond b. See: jet piercing thermic drilling 3276

See: jet piercing thermistor An electrical resistor made of a material whose resistance varies sharply in a known manner with the temperature. Thermistors are commonly used for shipboard oceanographic temperature measurements because of their percentage response to unit temperature change and their great sensitivity. Hunt thermite a. Any fossil combustible substance. Tomkeieff b. An intimate mixture of aluminum powder and powdered iron oxide that when caused to react by strong heating emits a great deal of heat and yields alumina and a white-hot molten mass of metallic iron. Webster 3rd thermit process The energetic action of finely divided aluminum on a metallic oxide, when heated together, is utilized for the production of metallic iron manganese, chromium, tungsten, molybdenum, uranium, etc. The aluminum combines directly with the oxygen of the oxide, and the heat emitted by the reaction is sufficient to promote the fusion of the reduced metal. Nelson thermoanemometer See: thermometer anemometer thermocline Frequently used in geophysics to describe the decrease in temperature that always occurs at great depths. Hunt thermocouple Two conductors of different metals joined together at both ends, producing a loop in which an electric current will flow when there is a difference in temperature between the two junctions. Abbrev., tc. Lyman; Zimmerman thermodynamics The mathematical treatment of the relation of heat to mechanical and other forms of energy. AGI thermoelectric conversion 3277

The conversion of heat into electricity by the use of thermocouples. Lyman thermoelectricity Electricity involved in thermoelectric phenomena. Specif., electricity accumulated or put in motion by thermoelectric action. Webster 3rd thermoelectric metals Metals or alloys used in thermocouples for measuring high temperatures. Platinum, nickel, copper, rhodium, etc., are much used. Crispin thermograph A self-recording thermometer that gives a continuous trace of air temperature on a rotating drum worked by clockwork. It is mainly used for recording variations in temperature rather than actual temperatures. Hammond thermoluminescence The property of minerals to emit light when heated. It results from the release of energy stored by displaced electrons trapped in a crystal structure. See also: calorescence thermometamorphism See: thermal metamorphism thermometer An instrument for determining temperature usually by means of a scale graduated directly in temperature units and consisting typically of (1) a device having a bimetallic element, the expansion or contraction of which indicates a change in temperature, or (2) a glass bulb attached to a fine tube of glass with a numbered scale etched on it or fastened to it and containing a liquid (as mercury or cooled alcohol) that is sealed in and rises and falls with changes of temperature and that indicates the temperature by the number at the top of the column of liquid. Webster 3rd thermometer anemometer An anemometer consisting of two thermometers, one with an electric heating element (battery powered) connected to the bulb. The heated bulb cools in an airstream, and the difference in temperature as registered by the heated and unheated thermometers can be translated into air velocity by a conversion chart. It is nondirectional and can be made safe (6 V) for use in explosive atmospheres. Syn: thermoanemometer 3278

thermometer float This instrument is used for studying the temperature structure in the upper 10 m of water. The instrument is in two sections; a float, which contains a spooling winch from which the sensing unit is lowered, and an indicator case, which contains the remote indicating equipment and remote control system. The two sections are connected by an electric cable and flexible shaft, supported by net floats. The indicator case is clear lucite. It contains the indicating meter and electric circuitry for temperature determination. It also contains a Veeder-Root counter, which indicates directly in centimeters the depth at which the sensing unit is located. This instrument makes it possible to read temperature to within 0.1 degrees C and to know the depth of the sensing unit to within + or -0.5 cm. It is intended to be used at sea from a skiff or tender rather than from the research vessel itself. Hunt thermometer scales Two thermometer scales are in general use, the Fahrenheit, which is generally used in engineering, and the Celsius, which is almost universally used in scientific work. The Fahrenheit scale has the freezing point at 32 degrees F and the boiling point at 212 degrees F, whereas the Celsius scale has the freezing point at 0 degrees C and the boiling point at 100 degrees C. The Celsius scale is commonly called the centigrade scale. Nelson thermometric fan test A method of assessing the efficiency of a mine fan by comparing the temperature rise in an ideal isentropic fan for a given fan pressure with the measured temperature rise actually occurring in the fan under consideration when producing the same fan pressure. The ratio of isentropic temperature rise to the actual temperature rise across the fan gives the fan efficiency. The method gives an accuracy of + or -5%. See also: overall ventilation efficiency thermonatrite An orthorhombic mineral, Na2 CO3 .H2 O ; forms flat, white, water-soluble crystals in some lakes and alkali soils, also a saline residue. thermo-osmosis Natural migration of moisture from a relatively warm part of a mass of soil toward a cooler part. See also: electro-osmosis thermopile

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An apparatus consisting of a number of thermoelectric couples (as of antimony and bismuth or of copper sulfide and German silver) combined so as to multiply the effect used; (1) to generate electric currents for various purposes, and (2) in a very sensitive form for determining intensities of radiation due esp. to its heating effect. Webster 3rd thermoplastic In plastics, rigid material that temporarily becomes soft when heated and can then be molded into a shape that it will retain on cooling. Ant. for thermosetting, a material that reacts chemically on heating (curing) and is then resistant to deformation when reheated. Pryor, 3 thermoscopic bar Small ceramic bar of specified composition that softens at certain temperatures. See also: Holdcroft thermoscope bar thermostat An automatic device for regulating temperature (as by opening or closing the damper of a heating furnace or by regulating the supply of gas) and commonly utilizing either the differential expansion of solids or the vapor pressure of liquids. Webster 3rd Thetis hairstone Coarsely crystalline quartz containing inclusions of asbestiform amphibole, esp. hornblende or actinolite, that may be tangled or wound into a ball. See also: Venus hairstone; sagenitic quartz. thick-bedded A relative term applied to sedimentary beds variously defined as more than 2.5 in (6.4 cm) to more than 40 in (100 cm) in thickness; specif. said of a bed whose thickness is in the range of 2 to 4 ft (60 to 120 cm), a bed greater than 120 cm being very thick-bedded. CF: tight-bedded; thin-bedded. AGI thickener A vessel or apparatus for reducing the proportion of water in a pulp by means of sedimentation. Nelson thickening a. The process of concentrating a relatively dilute slime pulp into a thick pulp, i.e., one containing a smaller percentage of moisture, by rejecting liquid that is substantially solid 3280

free. Settling is another name for the same operation. Taggart, 1 b. The concentration of the solids in a suspension with a view to recovering one fraction with a higher concentration of solids than in the original suspension. BS, 5 thickness a. The distance at right angles between the hanging wall and the footwall of a lode or lens. Standard, 2 b. As used in mine subsidence, the thickness of a bed or seam of mineral is the distance from its roof to its floor, measured at right angles to the plane of stratification. Briggs c. That dimension designed to lie at right angles to the face of the wall, floor, or other assembly. ASTM thickness contour See: isopach thickness line See: isopach thick seam In general, a coal seam over 4 ft (1.22 m) in thickness. See also: medium-thickness seam thick-wall sampler A soil sampler made from a steel tube having a wall thickness greater than 16 gage. See also: drive sampler Shelby-tube sampler. Long Thiess process A chlorination process for recovering gold from its ore. For each ton (0.9 t) of ore in a revolving drum, 130 gal (492 L) of water, 30 lb (13.6 kg) of lime chloride, and 36 lb (16.3 kg) of concentrated sulfuric acid are added, and the drum is revolved for some time. A solution of gold chloride is thus obtained. Fay thill a. The floor of a coal seam. See also: underclay b. Eng. Seat earth or pavement of underclay directly underlying a coalbed, Newcastle. Raistrick c. A thin stratum of fireclay. Webster 3rd thimble An oval iron ring around which a rope end is bent and fastened to form an eye. Zern 3281

thimble joint A sleeve joint packed to allow longitudinal expansion. A slip expansion joint. Fay thin-bedded A relative term applied to sedimentary beds variously defined as less than 1 ft (30 cm) to less than 0.4 in (1 cm) in thickness; specif. said of a bed whose thickness is in the range of 2 to 24 in (5 to 60 cm), a bed less than 5 cm but more than 1 cm thick being very thinbedded. CF: tight-bedded; thick-bedded. AGI thinolite A tufa deposit of fibrous calcite pseudomorphous after an unknown precursor occurring on an enormous scale in northwestern Nevada; also occurs about Mono Lake, CA. It forms layers of interlaced pale yellow or light brown crystals, commonly skeletal with pyramidal terminations. Syn: thinolitic tufa thinolitic tufa See: thinolite thin out To grow progressively thinner in one direction until extinction. The term is applied to a stratum, vein, or other body of rock that decreases gradually in thickness so that its upper and lower surfaces eventually meet and the layer of rock disappears. The thinning may be original or due to truncation beneath an unconformity. Syn: pinch out; wedge out. AGI thin seam In general, a coal seam 2 ft (0.6 m) and under in thickness. See also: economic coal reserves thin-seam miner An adaptation of the auger surface miner, the thin-seam miner cuts an entry 8 ft (2.4 m) wide and up to 5 ft (1.5 m) high into coal located under the highwall in surface mines. SME, 1 thin section a. A fragment of rock or mineral mechanically ground to a thickness of approx. 0.03 mm, and mounted between glasses as a microscope slide. Rocks and most minerals 3282

except the oxides and sulfides of the metals are translucent to transparent in thin section, and the optical properties of each mineral can be studied with the microscope. See also: polished section b. A rock or mineral slice cut for study by transmitted light with a polarized-light microscope. It may also be polished for study with a reflected-light microscope. c. A coal seam less than its normal thickness. Nelson thin stock Slabs of stone employed for wainscoting, flooring, etc. Fay thin-wall bit A coring bit the kerf or wall thickness of which is about one-half or less that of the wall thickness of the same outside-diameter-size standard coring bit. Long thin-wall drive sampler See: Shelby tube; thin-wall sampler. thin-wall sampler A soil-sampling barrel made from steel tubing having approx. a 16-gage wall thickness. Syn: thin-wall drive sampler; thin-wall tube sampler. CF: Shelby tube thin-wall tube sampler See: thin-wall sampler Thiobacillus ferrooxidans A bacterial strain that catalyzes the oxidation of ferrous iron (Fe+2 ) to ferric iron (Fe+3 ). SME, 1 Thiobacillus thiooxidans A bacterial strain that catalyzes the oxidation of sulfur to sulfate (SO4-2 ). SME, 1 thio-carbanilid A derivative from thio-urea. In the flotation process, it is used as a collector agent of low solubility in water; it is sometimes used in copper or galena flotation. Pryor, 3 thiocarbonates Powerful collector agents in the flotation process where xanthates fail. Pryor, 3 3283

thiofuran See: thiophene thiokerite Kerite containing 9% sulfur. Tomkeieff thiophene A liquid; C4 H4 S ; analogous to furan and pyrrole in its heterocyclic structure and resembles benzene both physically and chemically except for its greater reactivity. Found in small amounts (as up to 0.5% by weight) in benzene from coal tar unless it has been removed by treatment with sulfuric acid. Used chiefly in organic synthesis. Syn: thiofuran thiophile elements Equivalent to chalcophile. Literally, sulfur-loving. See also: chalcophile thiophosphates Sulfydric flotation agents, produced by reacting phosphorus pentasulfide with phenols, alcohols, etc., and marketed as Aerofloats. Pryor, 3 third-class lever A lever to which force is applied between the fulcrum and the work point. Nichols, 1 Third Theory of Comminution The Third Theory states that the specific work input required for size reduction is inversely proportional to the square root of the product size, less the work required to form the feed. Pit and Quarry thirl a. A cross hole or ventilation passage between two headings. See also: thurl; thurling; thirling. Standard, 2 b. To cut out the lost coal between two workings or headings. CTD c. To cut through from one working into another. CTD thirling

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a. The driving of a proposed roadway from two points some distance apart to meet each other; the connecting of underground roadways or shafts. Nelson b. See: thirl; crosscut; through cut. c. See: holing; stenton. this vein A notice claiming a location upon this vein has only one meaning. It raises an inference that the notice was posted upon or in close proximity to a vein or lode, although, as a fact, no vein or lode then was exposed. Ricketts thixotropic fluid Clays termed thixotropic are those that reveal this property by weakening when they are remolded and by increasing in strength when allowed to stand undisturbed. See also: remolding oil-well drilling fluids. Hammond thixotropy a. The property of certain colloidal substances, such as a thixotropic clay, to weaken or change from a gel to a sol when shaken, but to increase in strength upon standing. AGI b. The property of a material that enables it to stiffen in a relatively short time on standing, but upon agitation or manipulation to change to a very soft consistency or to a fluid of high velocity, the process being completely reversible. Used in muds for drilling deep oil wells since, if the drill stops, rock chips on the way to the surface are held in suspension instead of settling to the bottom where they might jam the drilling bit. See also: gel; plastic deformation. ASCE tholeiite A silica-oversaturated (quartz-normative) basalt, characterized by the presence of lowcalcium pyroxenes (orthopyroxene and/or pigeonite) in addition to clinopyroxene and calcic plagioclase. Olivine may be present in the mode, but neither olivine nor nepheline appear in the norm. CF: basalt thomaite A variety of siderite that is found massive and in pyramidal crystals. Standard, 2 Thomas converter A bottom-blown basic pneumatic converter having a basic bottom and lining, usually dolomite, and employing a basic slag. ASM, 1 Thomas-Gilchrist process 3285

Conversion of iron to steel in basic-lined Bessemer converter. Phosphorus combines with dolomite in this lining to produce basic slag. Pryor, 3 Thomas slag The finely powdered basic slag obtained in the Thomas-Gilchrist process. It consists of phosphates and is used as a fertilizer. Hackh Thomas steel Steel made in a Bessemer converter using a basic refractory lining. The process was developed by Thomas and Gilchrist. In Europe such steel is known as Thomas steel; in Great Britain, Thomas-Gilchrist steel; and in the United States, basic Bessemer steel. Henderson Thompson arc cutter See: arc cutter thompsonite An orthorhombic mineral, Na4 Ca8 [Al20 Si20 O80 ].24H2 O ; zeolite group; pseudotetragonal; occurs in amydules and crevices in basalts and tuffs; also an alteration of anorthite. Also called ozarkite. Thompson pilot shoulder reamer A reaming or coring bit with an articulated steel pilot protruding about 36 in (91 cm) beyond the face of the bit. The diameter of the pilot is slightly smaller than the set inside diameter of the bit; its upper end is a piston fitted tightly inside a single-tube barrel with its attached coring bit. When lowered into a borehole in which a deflection wedge has been set, the pilot section forces the coring bit to ream out the first part of the deflected hole at a point about 20 in (51 cm) above the tip of the wedge. Reaming is continued to about 6 in (15 cm) below the wedge tip, at which point the pilot shoulder reamer is withdrawn and replaced by a bullnose or deflection bit. Long Thompson wedge A retrievable type of deflecting wedge. See also: deflecting wedge Long thomsenolite A monoclinic mineral, NaCaAlF6 .H2 O ; dimorphous with pachnolite; forms small, white prismatic crystals on cryolite. 3286

thoreaulite A monoclinic mineral, SnTa2 O6 ; forms a series with foordite; brown; in pegmatite at Katanga, Congo. thoria A rare refractory oxide, ThO2 . thorian gummite See: thorogummite thorianite An isometric mineral, ThO2 ; commonly contains lanthanides; has fluorite structure; forms a series with uraninite; highly radioactive and metamict; sp gr, 9.7; in pegmatites; in placers associated with zircon, ilmenite, geikielite, thorite, and other heavy minerals; an important source of uranium and thorium. Also called isometric thorium. thorian uraninite A variety of uraninite containing thorium in partial substitution for uranium. Crosby thorium borides Two borides are known: ThB4 (gray) and ThB6 (deep red). More attention has been paid to the tetraboride, the properties of which are melting point, >2,200 degrees C (but oxidizes slowly above 1,000 degrees C); thermal expansion, 5.9X10-6 (20 to 1,000 degrees C); sp gr, 8.45 g/mL; modulus of rupture (20 degrees C), 20,000 psi (138 MPa) . Some properties of ThB6 are melting point, 2,200 degrees C; sp gr, 7.1. Dodd thorium carbides Two carbides are known: ThC, melting point, 2,625 degrees C; ThC2 , melting point, 2,655 degrees C. These special carbides are of potential interest in nuclear engineering. Dodd thorium disintegration series The series of radioactive elements produced as successive intermediate products when the element thorium (thorium 232) undergoes its spontaneous natural radioactive disintegration into stable lead (lead 208). CCD, 2 thorium mineral 3287

One of several minerals including monazite, in which Th replaces rare earths; thorite, ThSiO4 ; and thorianite, ThO2 . thorium nitride Three thorium nitrides have been reported: ThN, Th2 N3 , and Th3 N4 . Dodd thorium sulfides Three thorium sulfides have been reported: Th4 S7 , Th2 S3 , and ThS . Crucibles made of these sulfides have been used as containers for molten cerium. Dodd thorogummite A tetragonal mineral, Th(SiO4 )1-x (OH)4x ; may contain up to 31% uranium; has zircon structure. Differs from thorite (1) in being secondary, formed by the alteration of primary thorium minerals including thorite itself; (2) in not being metamict but forming crystalline aggregates; and (3) in containing essential (OH). Syn: thorian gummite; mackintoshite; maitlandite. thoron A name for radon 220, a member of the thorium disintegration series; symbol, Tn; emits alpha particles; and half-life, 5.5 s. Also called emanation; thorium emanation. Handbook of Chemistry and Physics, 2 thorosteenstrupine A mineral, Na2 (Th,RE)(Mn,Ta,Fe)H2 [(Si,P)O4 ]3 ; metamict; dark brown to black. thorotungstite See: yttrotungstite thorough joints Vertical joints affecting all the strata, as opposed to cricks or looses, oolite quarries, Northamptonshire, United Kingdom. Syn: upright joints thortveitite A monoclinic mineral, (Sc,Y)2 Si2 O7 ; may contain up to 42% yttrium replacing scandium; weakly radioactive; grayish green where fresh, altering to white to reddish gray; in pegmatites associated with monazite, euxenite, beryl, struvite, and possibly fergusonite; the only known mineral rich in scandium. 3288

Thoulet's law Heavy mineral suites increase in complexity with decreasing geologic age. Thoulet solution A yellowish-green, transparent, aqueous solution of potassium mercuric iodide, having a maximum specific gravity of 3.19. Also known as Sonstadt solution. Used in the sinkfloat process of mineral separation. Holmes, 2 thread a. An extremely small vein, even thinner than a stringer. Fay b. A more or less straight line of stall faces, having no cuttings, loose ends, fast ends, or steps. Fay c. To reeve rope or cable through a sheave or block and tackle. Long thread cutter A name sometimes applied to a diamond crystal having the shape of an octahedron. Long thread-lace scoria A scoria in which the vesicle walls have burst and are represented only by an extremely delicate three-dimensional network of glass threads. See also: reticulite three-circle goniometer See: goniometer three-cone bit See: roller rock bit. Also called tricone bit. three-dimension dip In seismic prospecting, the true dip of a reflection or refraction horizon found by exploration and calculation. See: true dip threefold An axial symmetry operation requiring three repetitions to complete 360 degrees or return to identity. Syn: triad three-high mill 3289

Consists of three horizontal rolls, one above the other, each rotating continuously in one direction only, the piece being rolled between the bottom and middle, and middle and top rolls alternately. Osborne three-hinged arch An arch hinged at its abutments and at its crown with the advantage that each half can sink in relation to the other without damaging the arch. Hammond three-jaw chuck A drill chuck having three serrated-face movable jaws that can be made to grip and hold fast an inserted drill rod. See also: chuck threeling In crystallography, a crystal of three parts united by the same twinning law. Syn: trilling three-part line A single strand of rope or cable doubled back around two sheaves so that three parts of it pull a load together. Nichols, 1 three-phase circuit Usually a three-wire circuit using alternating current with three equal voltages. This should not be confused with the three-wire service supplying 110 V and 220 V. This latter is merely a two-voltage single-phase circuit arrangement and is used almost universally to provide power and lighting to homes and small business establishments. Kentucky three-phase current Alternating current in which three separate pulses are present, identical in frequency and voltage, but separated by 120 degrees . Pryor, 3 three-phase inclusion An inclusion consisting of a liquid with a gas bubble and a crystal within a crystal. See also: negative crystal; inclusion. three-piece set

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A set of timber used in ground that requires greater support than a two-piece set or stull will provide. A cap is supported by two posts often spread apart at the bottom to give greater stability. See also: timber set; four-piece set. Lewis three-point problem a. In surveying, a method used to orient underground workings via three plumblines suspended in a vertical shaft. Pryor, 3 b. The problem in plane table surveying of locating precisely the point at which the table is set up, using three fixed points that are visible from the plane table. Hammond c. The problem of determining dip and strike of a plane from elevations determined at three known points not in a straight line. three-product washing A method in which the cleanest fraction of the coal with an ash content of 1% to 2% (for hydrogenation, etc.) is separated; the remainder giving coal with an ash content of 10% to 15% (for boiler firing, etc.) and finally incombustible shale. Nelson three-shift cyclic mining A system of cyclic mining on a longwall conveyor face, with coal cutting on one shift, hand filling and conveying on the next, and ripping, packing, and advancement of the face conveyor on the third shift. The system restricts coal production to one shift. Nelson three-term process controller Instrument that automatically regulates a process in proportional, integral, and derivative terms, thus neutralizing and removing the errors that arise during operation. Pryor, 3 three-throw ram pump This type of pump consists essentially of three single-acting ram pumps side by side, either vertical or horizontal, and driven from a triple crankshaft with cranks set at angles of 120 degrees . The three-throw pump can deal with heads up to 1,000 yd (900 m) in a single lift. Sinclair, 4 three-wire system A voltage improvement system that consists of the series operation of two generators. One circuit of a mine is fed from one generator, and a second circuit is fed from the other generator. The mine track or return is common to both generators and is connected between the generators. This method provides high voltage for transmission of power, yet the individual circuits provide normal low-voltage power. In effect, this is the Edison three-wire system, wherein the rails form the neutral third wire. The third wire (mine 3291

track) carries only the unbalance between the loads on the two separate circuits. Kentucky threshold a. In geochemical prospecting, the limiting anomalous value below which variations represent only normal background effects and above which they have significance in terms of possible mineral deposits. Hawkes, 1 b. In analytical chemistry, the limiting sensitivity of an analytical method, the detection limit. Hawkes, 1 Threshold Limit Value A time-weighted average concentration under which most people can work consistently for 8 hours a day, day after day, with no harmful effects. A table of these values and accompanying precautions is published annually by the American Conference of Governmental Hygienists. NSC, 2 throat a. The part of a blast furnace at the top of the stack. Dodd b. The zone of decreased cross section found between the port area and the furnace chamber in some designs of openhearth steel furnaces. Dodd c. The submerged passage connecting the melting end to the working end of a glass tank furnace; the refractory blocks forming the sides of the throat are known as throat cheeks, sleeper blocks, or dice blocks; the refractories for the top are the throat cover. See also: submarine throat d. The least thickness of a weld, the calculation of its strength being based on the thickness at the throat. Hammond throat of crusher Point at which the rock is discharged. Its short dimension varies, depending upon whether the swing jaw is in the open or closed position. Newton, 2 throttle To obstruct the flow of, as steam to an engine esp. by a throttle valve. Webster 3rd throttle valve A valve designed to regulate the supply of a fluid (as steam or gas and air) to an engine. Webster 3rd through A passage cut through a pillar to connect two rooms. Fay 3292

through cut An excavation between parallel banks that begins and ends at original grade. See also: thirling througher See: stenton throughput Quantity of material passed through the mill or a section thereof in a given time or at a given rate. Pryor, 3 through ventilation The normal ventilation produced in a mine as the air flows from the intake to the return, as opposed to ventilation produced locally by auxiliary fans. Nelson throw a. The amplitude of shake of a vibratory screen, concentrating table, jigger conveyor, etc. Nelson b. Lateral displacement of a screen, shaking table, or crushing surface in motion. Pryor, 4 c. The projection of broken rock during blasting. See also: flyrock Standard, 2; Fay d. The distance from an air supply opening measured in the direction of air flow, from the opening to the point where the air velocity is 50 ft/min (15.2 m/min). Strock, 2 e. The amount of vertical displacement up (upthrow) or down (downthrow) produced by a fault; sometimes, loosely, a dislocation not vertical, the direction being specified. See also: heave; perpendicular throw; stratigraphic throw. Fay f. The vertical component of the net slip on a fault. AGI thrower belt See: boxcar loader throwing clay Clay plastic enough to be shaped on a potter's wheel. thrown a. Faulted or broken up by a fault. Fay b. Turned, as a piece of ceramic ware on a potter's wheel. Standard, 2 throw of crusher 3293

See: stroke of crusher throwoff switch Aust. A switch by means of which an obstruction is thrown across the rails of a track, causing the derailment of the trucks. A derailing switch. throwout bearing a. A bearing, sliding on a clutch jackshaft, that carries the engage and disengage mechanism. Nichols, 1 b. A bearing that permits a clutch throwout collar to slide along the clutch shaft without rotating with it. Nichols, 1 thrust a. An overriding movement of one crustal unit over another, such as in thrust faulting. AGI b. See: thrust fault; fault. c. A crushing of coal pillars caused by excess weight of the superincumbent rocks, the floor being harder than the roof. CF: creep Fay d. The ruins of a fallen roof, after pillars and stalls have been removed. Fay e. The weight or pressure applied to a bit to make it cut. Long thrust arm A cable-controlled bar that can slide by power in two directions. Nichols, 1 thrust bearing a. A bearing that resists attempts of a shaft to move along its axis. Pryor, 3 b. A bearing designed to carry axial loads on a shaft. Shell thrust block The antifriction part of the thrust yoke attached to the drive rod in the swivel head of a diamond-drill machine. Also called cage; friction head; thrust collar. See also: thrust sheet thrust borer Mechanism for forcing a hole through an embankment for the insertion of pipes or cables. Hammond thrust fault a. A fault with a dip of 45 degrees or less over much of its extent, on which the hanging wall appears to have moved upward relative to the footwall. Horizontal compression 3294

rather than vertical displacement is its characteristic feature. CF: normal fault Syn: thrust; overthrust. AGI b. A reverse fault that is characterized by a low angle of inclination with reference to a horizontal plane. AGI c. A reverse fault heading at a high angle. BS, 11 thrust nappe See: thrust sheet thrust plane a. The surface of a thrust fault, when the surface is planar. AGI b. The plane of a thrust or reversed fault. Syn: overthrust plane thrust plate The upper and/or lower race parts of the thrust bearing in the thrust block or cage on the drive rod in a diamond-drill swivel head. Syn: thrust race thrust race See: thrust plate thrust sheet The body of rock above a large-scale thrust fault whose surface is horizontal or very gently dipping. Syn: thrust block; thrust nappe; thrust plate. AGI thrust washer A washer that holds a rotating part from sideward movement in its bearings. Nichols, 1 thrust yoke The part connecting the piston rods of the feed mechanism on a hydraulic-feed diamonddrill swivel head to the thrust block, which forms the connecting link between the yoke and the drive rod, by means of which link the longitudinal movements of the feed mechanism are transmitted to the swivel-head drive rod. Also called back end; cage. Long thulite An intense pink variety of zoisite containing manganese; an ornamental stone. Thum-Balbach process 3295

A silver refining process using carbon cathodes, dore anodes, and a silver nitrate-nitric acid electrolyte. The silver is scraped off the bottom as crystals. Liddell thumb-marked fracture The minute ripples or thumbmarks characteristic of the fractured surface of amethyst. CMD Thum furnace A gas-fired furnace esp. for the treatment of zinc ore that is high in lead. Fay thunderbolt a. A stone or stony concretion, esp. if elongated and tapering, found in the ground and ignorantly supposed to have fallen from the sky. Standard, 2 b. A nodule or mass of iron pyrites found in English chalk formations. Standard, 2 thunder egg A popular term for a small, geodelike body of chalcedony, opal, or agate that has weathered out of the welded tuffs or lava, particularly from central Oregon. AGI thuringite A monoclinic mineral, [Fe(OH)2 (AlSi3 O10 )].3[(Mg,Fe)(OH)2 ] ; pseudohexagonal; forms monoclinic plates having micaceous cleavage; an iron-rich chamosite. thurl S. Staff. To cut through from one working into another. Also spelled thirl. Fay thurling A passage cut from room to room, in post-and-stall working. See also: thirl; thirling. Fay thwarting A short tunnel driven between two or more veins where they are nearly vertical. Nelson thyratron A gas-filled valve or tube in which the initiation of current in an ionized gas or vapor is controlled by the voltage applied to a control electrode. NCB 3296

Thyssen gravimeter An early gravity meter of the unstable equilibrium type. AGI Tibet stone A mixture of aventurine quartz and quartz porphyry that may be of various colors and has been cut as ornamental or curio stones, in Russia. ticket a. A sealed bid for ore to be sold. Webster 3rd b. The numbered check that the miner puts on his loaded car to inform the weighmaster to whom the coal belongs. See also: tag; tally. Fay tick hole A small cavity in a rock; a vug. Fay tidal flat An extensive marshy or barren tract of land that is alternately covered and uncovered by the tide, and consisting of unconsolidated sediment (mostly mud and sand). It may form the top surface of a deltaic deposit. See also: sabkha tidal marsh See: tidal flat tide flat See: tidal flat tidelands Technically lands overflowed during floodtide, but the term, by reason of the so-called Tidelands cases, has been used to describe that portion of the continental shelf between the shore and the claimed boundaries of the States--3 miles or 9 miles (4.8 km or 14.4 km) at sea. Williams tie a. A beam, post, rod, or angle to hold two pieces together; a tension member in a construction. Webster 3rd b. One of the transverse supports to which railroad rails are fastened to keep them to line, gauge, and grade. Webster 3rd c. Linear or angular 3297

measurements or a combination of the two made for the purpose of locating other points from points of known position. Ties may be made to connect physical objects with the survey line, or to locate the instrument point with reference to physical objects so that it can be reestablished if lost. To tie in is to close a survey on itself or on another survey, or to locate a point by means of ties. Seelye, 2 tieback a. A beam serving the purpose similar to a fend-off beam, but fixed at the opposite side of the shaft or inclined road. Fay b. The wire ropes or stayrods that are sometimes used on the side of the tower opposite the hoisting engine, in place of or to reinforce the engine braces. Fay tie bar a. A bar used as a tie rod. Webster 3rd b. A rod between two railway switch rails to hold them to gauge. Webster 3rd tied retaining wall A retaining wall tied into the adjoining ground by means of a deadman (wood block) or other suitable anchorage. Hammond tie line a. A line at constant temperature that connects any two phases that are in equilibrium at the temperature of the tie line. Syn: conode b. A line measured on the ground to connect some object to a survey; e.g., a line joining opposite corners of a four-sided figure, thereby enabling its area to be checked by triangulation. AGI tiemannite An isometric mineral, HgSe ; has sphalerite structure; dark gray to black. tie plate A metal plate used under rails where they rest on ties. The rail is spiked to the tie through holes in the plate. Jones, 1 tie point a. A point to which a tie is made; esp. a point of closure of a survey either on itself or on another survey. AGI b. An image point identified on oblique aerial photographs in the overlap area between two or more adjacent strips of photography. They tie individual 3298

sets of photographs into a single flight unit and adjacent flights into a common network. AGI tie pumping When track is not adequately drained and water enters the ballast and roadbed, tie pumping occurs. Under the action of the rolling stock, pressure on the tie discharges water to the surface, washing the ballast from beneath and around the tie. tie rod A round or square iron rod passing through or over a furnace and connected with a buckstay to assist in binding the furnace together. Fay tierra Sp. Any rock or mineral; tierra blanca (Mex.), a calcareous tufa; tierra de batan, fuller's earth; tierra de fluor (Venez.), a bed of reddish clayey earth; tierra de porcelana, china clay; tierra pesada, heavy spar. Fay tierra blanca A Spanish term for white ground or white earth, and applied to white calcareous deposits such as tufa, caliche, and chalky limestone. AGI tiff a. Sparry calcite in Wisconsin and southwestern Missouri zinc fields. b. Sparry barite in southeastern Missouri. tiffanyite A hydrocarbon present in certain diamonds causing phosphorescence. tiger A device, as a fork, for supporting a continuous series of well-boring rods or tubes while raising or lowering them in the hole. Standard, 2; Fay tigereye Alternative spelling of tiger's-eye. tiger's-eye 3299

a. A usually yellow-brown chatoyant stone that is much used for ornament and is a silicified crocidolite in which the fibers penetrating the quartz are changed to oxide of iron. Also spelled tigereye. CF: hawk's-eye See also: occidental cat's-eye; oriental cat'seye. Webster 3rd b. Crocidolite asbestos replaced by quartz to yield a yellow-brown chatoyant stone used for ornament. c. Ceramic glaze resembling tiger's-eye. tight a. Soil or rock formations lacking veins of weakness. Syn: tight formation b. Blasts or blastholes around which rock cannot break away freely. Nichols, 1 c. Inadequate clearance or the barest minimum of clearance between working parts. Long d. Unbroken, crack-free, and solid rock in which a naked hole will stand without caving. Long e. A borehole made impermeable to water by cementation or casing. Long f. An impermeable rock formation. Long g. An underground opening having limited space in which to work. Long h. Lacking in porosity; impervious. Wheeler, R.R. tight-bedded In sandstone quarrying, a term used to describe the rock if it is massive, showing no open-bed seams. CF: thin-bedded; thick-bedded. AIME, 1 tight-burning clay A clay that is dense or approaches vitrification after firing. tight formation See: tight; tight rock. tight hole a. A borehole the diameter of which is too small for adequate clearance between the drill-stem equipment and/or inserted casing. Long b. A borehole the wall rocks of which are impermeable to water or have been made tight by cementation or insertion of casing. Long c. A borehole-drilling operation, access to which and information about which are not released except to authorized persons. Long tight lagging Lagging placed touching each other. See also: tight sheathing tight rock a. Rock formation in which the joints, cracks, or crevices are sealed and impermeable to water. Long b. Rock composed of tightly cemented grains of very fine, even-sized 3300

crystals. Long c. Rock that does not chip easily under the impact of cable tools. Long d. A tough, resilient rock. Long e. Can. Without evidence of shearing or mineralization. Syn: tight formation tightset A quarrymen's term, equivalent to blind seam, or incipient joint. Fay tight sheathing The most complete sheathing using wood timbering. Used where water or fine wet soils must be retained. The frame is designed for this use and is generally stronger than that required for other types of sheathing. A specially edged plank, generally tongue-andgrooved, eliminates the crevices existing in close sheathing. CF: close sheathing; skeleton sheathing. See also: tight lagging tight shot An explosive shot that has been set off to loosen coal in a seam that has not been previously cut or sheared. BCI tilasite A monoclinic mineral, CaMg(AsO4 )F ; isomorphous with isokite; violet-gray; at Laangban, Sweden, and Kajlidongri, Central India. tile copper Copper obtained by roasting and refining the metal bottoms that collect under the regulus in smelting certain impure ores; usually cast in flat, rectangular plates, hence its name. See also: bottoms Standard, 2 tile machine A machine for making tubular or arch-shaped tiles from clay, operating by forcing the raw material through a die, in a continuous stream, which is cut into suitable lengths by wires. Standard, 2 tile ore An earthy variety of cuprite, brick red because of admixed iron oxides. tiler a. A kiln or oven for baking tiles. Standard, 2 b. A maker or layer of tiles. Standard, 2 3301

tile shoe A device that permits laying tile directly behind a ditcher. Also called tile box. Nichols, 1 tile works A tilery or tile field. Standard, 2 tilgate stone Beds of calcareous sandstone or ironstone, near Hastings, England. Fay till Dominantly unsorted and unstratified drift, generally unconsolidated, deposited directly by and underneath a glacier without subsequent reworking by meltwater, and consisting of a heterogeneous mixture of clay, silt, sand, gravel, and boulders ranging widely in size and shape. See also: boulder clay; moraine. Syn: glacial till; ice-laid drift. AGI tiller rope A flexible wire rope composed of six small ropes, usually of seven wire strands each laid about a hemp core. Zern tilleyite A monoclinic mineral, Ca5 (Si2 O7 )(CO3 )2 ; forms white grains in rock at Crestmore, CA. tillite A consolidated or indurated sedimentary rock formed by lithification of glacial till, esp. pre-Pleistocene till (such as the Late Carboniferous tillites in South Africa and India). AGI tilt a. The angle at the perspective center of an aerial photograph between the plumb line and the perpendicular from the interior perspective center to the plane of the photograph. AGI b. The lack of parallelism (or the angle) between the plane of the photograph from a downward-pointing aerial camera and the horizontal plane (normal to the plumb line) of the ground. AGI c. In aerial photography, the angle between the lens axis and a vertical through the exposure station (rear nodal point of lens). It is seldom more than 3 degrees and can generally be kept to 1 degrees . This is regarded as satisfactory for 3302

vertical photographs. Seelye, 2; Hammond d. To hammer or forge with a tilt hammer; as, to tilt steel to render it more ductile. Standard, 2 tilt hammer A hammer for shingling or forging iron, arranged as a lever of the first or third order, and tilted or tripped by means of a cam or cog gearing and allowed to fall upon the billet, bloom, or bar. Fay tilting dozer A bulldozer whose blade can be pivoted on a horizontal center pin to cut low on either side. Nichols, 1 tilting furnace Open-hearth furnace swung about its major axis when pouring out the melted product. Pryor, 3 tilting gate A crest gate for dam spillways designed so that water pressure acting upon it will do so only at a definite level. It closes automatically when the water level falls to normal. Hammond tilting idlers An arrangement of idler rollers on a conveyor in which the top set is mounted on vertical arms which pivot on spindles set low down on the frame of the roller stool. This permits the entire carrier frame to lean forward slightly in the direction of belt travel. In the event of the belt not running true, the tilting idlers guide it back to its correct course again. Nelson tilting level A surveying instrument with sighting telescope so mounted that it can be raised or lowered through a limited arc without impairing accuracy of reading, though axis of rotation is not precisely horizontal. The bubble tube is usually mounted alongside the telescope and is viewed from the eyepiece and through an optical sighting arrangement, which either brings opposite halves of the bubble image into coincidence or the end of the bubble to a reference line. Pryor, 3; Mason tilting mixer

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A concrete mixer with a rotating drum, which is tilted to discharge its contents. Hammond timber a. Any of the wooden props, posts, bars, collars, lagging, steel joists or beams, etc., used to support mine workings. Fay b. To set or place timbers in a mine. Fay c. Applied to rough blocks of natural rock as it comes from a quarry before being shaped into sharpening stones. Mersereau, 2 timber boss See: timberman timber drawer a. An appliance for withdrawing timber supports from wastes, e.g., a sylvester. Nelson b. A miner engaged in timber drawing. Nelson c. See: timber puller timber drawing See: drawing timber timbered stope Stope in which square-set timbering and its variations are employed. As a rule, the ground is broken by overhand methods, the face being advanced by successive small excavations, each one timbered before the next is begun. Higham timberer One who cuts, frames, and/or puts in place any of the timbers used in a shaft, slope, mine, or tunnel. Also one who draws props, posts, etc. Syn: timberman timber foreman See: timberman timbering a. The operation of setting timber supports in mine workings or shafts to support the roof or the face of a tunnel during excavation and lining. The term "support" would cover the setting of timber, steel, concrete, or masonry supports. See also: setting; timber set; face timbering; pin timbering. Nelson b. Timber work taken collectively in a mine. Standard, 2 c. Protecting against falls of roof formation of a mine, by means of horizontal timbers 3304

or caps extending across the passageway just under the roof, the ends of such timbers resting upon the vertical timbers or posts. Ricketts d. Timber to support the roof or the face of a tunnel during excavation and lining. Stauffer timbering machine An electrically driven machine to raise and hold timbers in place while supporting posts are set after being cut to length by the machine's power-driven saw. timbering set A tunnel support consisting of a roof beam, or arch, and two posts. Nichols, 1 timber jack A jack to raise and hold crossbars against the roof while props are being set. Hess timberman a. In bituminous coal mining, a head timberman is a foreman who supervises workers installing timbers in a mine to support the roof and walls of haulageways, passageways, and the shaft. Also called timber boss; timber foreman. DOT b. A miner skilled in notching, erecting, and securing timbers set in mine workings. The craft of the timberman is gradually becoming extinct with the advent of power tools and steel as a support. Nelson c. See: roof bolter; timberer. timberman helper In mining, a laborer who assists a timberman in erecting supports for the roof of a mine, using posts, headers, cap pieces, and wedges. DOT timber mat Broken timber forming roof of ore deposit being extracted by caving methods such as top slicing. It separates the downward gravitating overburden and rock strata from the ore. Pryor, 3 timber packer a. A laborer who delivers timber to the working place in a pitching or inclined coal seam. Fay b. See: pack builder timber pickling A method to assist timber preservation; e.g., creosoting. See also: timber preservation 3305

timber preservation Any treatment of mine timber for the purpose of extending the useful life of the timber. Various preservatives are used, such as creosote, zinc chloride, sodium fluoride, and other chemicals. See also: brush treatment; guniting; open-tank method; pressure process; Bethell's process; timber pickling; seasoning timber. Lewis timber puller a. A piece of equipment used in removing the supports or timbers in a mine. A timber puller should be constructed so that the operator will be under safe roof while drawing the timber. A sylvester is an example of this type of equipment. Also called timber drawer. Kentucky b. See: timber robber timber rights The right to cut timber on the public domain for commercial use. timber robber In anthracite and bituminous coal mining, a laborer who pulls out and recovers timbers and props in working places from which all coal has been mined. Also called prop drawer; timber puller. DOT timber set A timber frame to support the roof, sides, and sometimes the floor of mine roadways or shafts. For a mine roadway, the simplest timber set consists of a crossbar, cap, or collar supported on two upright posts or arms with round or board lagging. Such a set will resist roof pressure and moderate side pressure and is erected at intervals of from 2 to 6 ft (0.6 to 1.8 m). The timbers are about 5 to 10 in (12.7 to 25.4 cm) in diameter. In South Wales, such a timber set is known as double timber. See also: timbering; bar timbering; two-piece set; three-piece set; four-piece set. Nelson timber trolley A strong carriage of low height for transporting timber from the surface stockyard to underground workings. It consists of a timber or steel base, mounted on wheels, with Ushaped arms in which the timber is lashed with chains. See also: bogie timber truck Any truck or car used for hauling timbers inside a mine. In conveyor work, it is applied to the small truck mounted on wheels that is designed to run in the panline of a shaker conveyor for the purpose of carrying timber and other materials to the face. Jones, 1 3306

time-and-motion study The coordination and analysis of the data provided by time study and motion study. Nelson time at shot point In seismic exploration, the time required for the seismic impulse to travel from the charge in the shothole to the surface of the Earth. Syn: uphole time time break An indication on a seismic record showing the instant of detonation of a shot or charge. CF: time signal time mark. AGI time correlation Correlation of rocks in one area with those of another area on basis of time equivalence or contemporaneity of origin. time-delay relay Relay that does not operate until a predetermined time has elapsed. The time ratings are usually adjustable, but some time-delay relays have the time rating built into them. Coal Age, 3 time-depth chart A graphical expression of the functional relation between the velocity function and the times observed in the seismic method of geophysical exploration. It permits time increments to be converted to corresponding depths. Syn: time-depth curve time-depth curve See: time-depth chart time-distance curve In refraction seismic computations, a graph, usually with arrival times of distinctive seismic signals plotted as ordinates and with distances along the surface of the Earth plotted as abscissas. In earthquake studies, the times of arrival of seismic waves at recording stations may be known, but the time of initiation of the waves may be unknown. As data are accumulated from different recording stations, a time-distance graph may be constructed. If it is possible to extrapolate this graph to the origin on the time and distance coordinates, it becomes a travel-time curve. AGI 3307

time-distance graph In refraction seismic computations, a plot of the arrival times of refracted events against the shot-point-to-detector distance. The reciprocal slopes of the plotted segments are the refraction velocities for the refracting bed. AGI time gradient In the reflection seismic methods applied to dipping reflectors, the travel time curves may not be straight lines; i.e., the apparent velocity observed varies with the spread from shot point to detectors. The time gradient is the reciprocal of the apparent velocity. In seismic prospecting, also the rate of change of travel time with depth. AGI time lag a. In refraction seismic interpretation, where arrival times are plotted against shotdetector distances, if some of the paths from shot point to detector include a low-speed bed, the corresponding arrival times will be abnormally long, and the departure from normal travel time is called a time lag. Also, in seismic prospecting, time delays in arrivals due to phase shifts in filtering, to shot-hole fatigue, etc. AGI b. A delay in the arrival time of seismic energy from the time expected. Time lags may be produced by an abnormal low-velocity layer, phase shifts in filtering, or other factors. AGI time leads In a method of interpretation of refraction seismic records where the arrival times are plotted against shot-detector distances, if some of the paths from shot point to detector include a high-speed segment, the corresponding travel times will not fall on a smooth curve. The departure in this case from the curve is called a time lead, and it is proportional to the horizontal extent of the high-speed segment. Used in salt-dome exploration. AGI time mark a. See: time break b. Mark corresponding to a particular time (e.g., hour, minute, and second time marks) on a seismic recording. timer lines Lines on a seismogram that mark increments of time. Schieferdecker time-rock unit See: time-stratigraphic unit 3308

time scale See: geologic time scale time signal In geophysics, a signal used to indicate the time of explosion in a shothole and successive intervals of time on the recording. CF: time break time-stratigraphic unit A body of rock established to serve as the material reference for all rocks formed during the same span of time. Each of its boundaries is synchronous. Chronostratigraphic units in order of decreasing rank are eonothem, erathem, system, series, stage. Syn: chronostratic unit; chronolithologic unit; time-rock unit; chronolith. AGI time study A detailed investigation in which the average time taken to do each operation of a complete cycle is recorded. See also: method study; motion study. Nelson time tie In seismograph continuous profiling, a coincident travel path for seismic energy initiated at opposite ends of the path. The use of such coincident travel paths on adjacent reflection layouts facilitates correlation from one layout to the next as the shot point or recording position is changed. AGI time-transgressive See: diachronous time value The interval of geologic time represented by or involved in producing a stratigraphic unit, an unconformity, the range of a fossil, or any geologic feature or event. AGI timing The time elapsing between two successive exposures of an aircraft camera when taking vertical photographs. See also: photogrammetry Hammond timing line

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One of a series of marks or lines placed on seismic records at precisely determined intervals of time (usually at intervals of 0.01 or 0.005 s) for the purpose of measuring the arrival time of recorded events. AGI tin a. A tetragonal mineral, Sn : rare; soft; malleable: bluish white. b. The metal extracted from cassiterite; used as a coating to protect iron and copper, such as a foil, and in solder, bronze, and other alloys. Commercially, tin is available in three grades: Grade A must assay 99.75%; grade B must assay 99.7%; and grade C, or common tin, must assay 99% tin. c. To coat with tin, such as to tin iron; tinplate. Standard, 2 d. Metallic element that has a highly crystalline structure. Symbol, Sn. Found chiefly in cassiterite, SnO2 . Used in alloys such as soft solder, type metal, fusible metal, pewter, bronze, and bell metal and as a crystalline tin-niobium alloy. Handbook of Chemistry and Physics, 3 e. See: zinn tin bound a. Corn. To mark a limit, as on a tract of waste land, within which one claims or reserves the right to mine unworked tin ore. Standard, 2 b. Land so reserved. Standard, 2 tincal The name given, since early itmes, to crude borax obtained from salt lakes in Kashmir, India, and Xizang (formerly Tibet), China. Also spelled tinkal. Syn: borax tincalconite A trigonal mineral, Na2 B4 O5 (OH)4 .3H2 O . Syn: mojavite; octahedral borax. tin-can safety lamp A Davy lamp placed inside a tin can or cylinder having a glass in front, airholes near the bottom, and an open top. Fay tinder ore An impure variety of jamesonite. Standard, 2 tin dish A pan used by prospectors for washing gold-bearing materials and extracting the gold. See also: pan tin dredging 3310

The extraction of tin-bearing ore from placers by means of dredges. Nelson tine The actual excavating tooth or point of a grab bucket, scraper loader, dragline, or excavator bucket. Hammond tin floor a. Corn. A thin flat mass of tinstone between beds of rock. Fay b. A flat mass of tin ore. Standard, 2 tinge A color designation. A faint trace of a hue that modifies another hue, as a blue with a tinge of green, i.e., blue tinged with green or, stated differently, very slightly greenishblue. tin ground Corn. Tin-bearing alluvium, stream works. Arkell tin hat A head covering made of reinforced sheet aluminum or plastic-impregnated fabric and shaped somewhat like a sun helmet; worn for protection and/or to reduce the severity of head injuries from falling objects. Also called hard hat. Syn: safety hat tinkal See: tincal tinker Derb. Laminated carbonaceous shale. Fay tin minerals Virtually all the industrial supply of tin comes from cassiterite, SnO2 , though a little has been won from the sulfides stannite, cylindrite, and franckeite. Bulk of cassiterite comes from alluvial workings. Main market is in tin plating, tin foil, solders, bearing metals, bronze and other alloys, and such salts as opacifiers and dye mordants. Pryor, 3 tinned sheet iron 3311

See: tin plate tinner A tinsmith. Webster 3rd tinning metal An alloy of equal parts of tin and lead; used by electrotypers for coating copper shells before backing. Fay tin ore See: cassiterite tin plate Sheet iron or steel, cleaned by pickling in acid and then passed through bath of molten tin to produce coating. Three grades are charcoal plate, coke plate, and crystallized. Tin is also deposited by electroplating. Syn: tinned sheet iron tin pyrites See: stannite tin salt See: salt of tin tin spar See: cassiterite tinstone See: cassiterite tin stone See: cassiterite tin-white cobalt See: smaltite 3312

tinworks A place or an establishment where tin is manufactured or mined. Standard, 2 tip a. The point at which loaded mine cars are dumped on the surface. Also called tipple. Hudson b. A piece of tool material secured to a cutter tooth or blade. ASM, 1 tipple a. Originally the place where the mine cars were tipped and emptied of their coal, and still used in that sense, but more generally applied to the surface structures of a mine, including the preparation plant and loading tracks. BCI b. The dump; a cradle dump. c. Aust. The tracks, trestles, screens, etc., at the entrance to a colliery where coal is screened and loaded. CF: dump T-iron a. An angle iron having T-shaped cross section. Fay b. T-rails used in a mine, as distinguished from wooden rails. Fay titan See: titanium; titanite. titanaugite See: titanian augite titanhornblende A titaniferous variety of hornblende. English titania a. See: titanium dioxide b. TiO2 . Also called titanium oxide; titanic dioxide; titanic oxide. A common constituent of iron ores. Used as a pigment, and it replaces zinc oxide in manufacturing white rubber and as a filler for paper; can be used alone as a refractory and as an electrical insulator. Its crystals show marked piezoelectric effects and have a greater brilliance and a higher refractive index than diamond. c. The minerals tetragonal rutile, anatase, octahedrite, and orthorhombic brookite. d. Commonly refers to synthetic white titanium dioxide that is produced mainly from ilmenite, FeTiO3 , that contains 50% to 54% TiO2. 3313

titanian augite See: titanaugite titanic anhydrite A white pulverulent titanium oxide, TiO2 , found native as brookite, octahedrite, and rutile, and a common constituent of iron ores. Also called titanic oxide. Fay titanic dioxide See: titanium dioxide titanic iron ore See: ilmenite titanic oxide See: titanium dioxide titanic schorl See: rutile titaniferous magnetite Magnetite containing titanium. Bateman, 2 titanite A monoclinic mineral, CaTiOSiO4 ; Ca is replaced by Sr, Ba, Na, Mn, Th, or rare earths; Ti is replaced by Al, Fe, Mg, Nb, Ta, V, or Cr; up to 1/5 of O2- may be replaced by (OH,F)- ; weakly radioactive: forms wedge-shaped crystals; a common accessory in felsic plutonic rocks, in gneisses, schists, and marbles; a source of titanium. Formerly called sphene. titanium A silvery-gray or iron-gray, metallic element. Symbol, Ti. Found in nature only in combined form; occurs chiefly in ilmenite (FeTiO3 ), and in rutile and titanite. Used as an alloying agent with aluminum, molybdenum, manganese, iron, and other metals. Used in aircraft and missiles and has potential for use in desalination plants. Handbook of Chemistry and Physics, 3 3314

titanium carbide A compound produced by fusing titanium dioxide with carbon or calcium carbide. Has a melting point in the range of 3,140 to 3,160 degrees C. This very hard, refractory material is used for wear-resistant applications and where good thermal shock resistance is needed, as in bearings, nozzles, and special refractories under either neutral or reducing conditions. Lee titanium dioxide a. Also called titanium oxide, titanic dioxide, titanic oxide, titania, rutile, anatase, or brookite. Colorless, white, pale yellow or yellowish-red, reddish-brown, brown, blue or bluish, violet, and black; tetragonal and orthorhombic; TiO2 ; molecular weight, 79.90; sp gr, 3.82 to 5.13 depending on crystal system and crystal form; Mohs hardness, 5.5 to 6.5; melting point, 1,825 to 1,850 degrees C; boiling point, 2,500 to 3,000 degrees C; insoluble in water and in most acids; and soluble in hot concentrated sulfuric acid and in alkalies. Titanium dioxide occurs as the minerals rutile (tetragonal); anatase or octahedrite (tetragonal); and brookite (orthorhombic). Titanium dioxide is a common constituent of iron ores. Handbook of Chemistry and Physics, 2; CCD, 2 b. Titanium dioxide as rutile: colorless, pale yellow, reddish-brown, red, bluish, violet, and black; tetragonal; adamantine to submetallic luster; refractive indexes, 2.616 and 2.903; sp gr, 4.26 and ranges from 4.18 to 5.13; Mohs hardness, 6.0 to 6.5; and the same melting points, boiling points and solubility characteristics as above. Titanium dioxide possesses the gredatest hiding power of all the white pigments. Used in glassware and in ceramics, in enamel frits, in welding rods, and single crystals are used as high-temperature transducers. Syn: titania; octahedrite. titanium dioxide pigments Any of three grades of titanium-dioxide-based pigments used in the production of paints, paper, and many other products requiring a white pigment with a high hiding power and chemical stability. Rutile and anatase grades are more or less pure titanium dioxide, but owing to a difference in crystal structure, they differ slightly in hiding power and chalking quality. Titanium dioxide of pigment quality is manufactured principally by treating finely ground ilmenite or titanium slag with concentrated sulfuric acid. Also used in ceramics and fiberglass, and in making titanium gems. USBM, 6 titanium nitride TiN; a special refractory material (melting point, 2,930 degrees C). It can readily be produced from TiC14 and NH3 . Dodd titanium oxide

3315

a. TiO2 ; used as an opacifier, particularly in vitreous enamels, and as a constituent of some ceramic colors. Titania and titanate electroceramics, for use in the radio frequency field, are based on this oxide and its compounds. Titania occurs in three crystalline forms: anatase, brookite, and rutile. Dodd b. See: titanium dioxide titanium silicide Ti5 Si3 ; sp gr, 4.2. This special ceramic has good resistance to high temperature oxidation, but not to thermal shock. Dodd titanium sponge The metal product from reducing titanium tetrachloride with magnesium in the Kroll process. It is called sponge because of its spongelike appearance. Sodium-reduced metal also is referred to as sponge. USBM, 7 titanmagnetite See: titanomagnetite titanmelanite A titaniferous andradite approaching schorlomite in composition; garnet group. titanomagnetite a. A titaniferous variety of magnetite with titanium in crystal solution. Syn: titanmagnetite b. A term for mixtures of magnetite, ilmenite, and ulvoespinel. CF: mogensenite titan process A process of concentrating iron ore that comprises the steps of (1) effecting a dry, thermal, partial reduction of the iron in the ore to the metallic state to a degree of reduction of between 50% and 80%, (2) subjecting the reduced product to a magnetic separation, and (3) recovering the magnetic concentrate. Osborne tithe ore Eng. A portion of ore set aside for the payment of rental or royalty on mineral lands. Fay title The right to enter, develop, and work a coal or mineral deposit. See also: claim; lease. Nelson 3316

TLV See: Threshold Limit Value toadrock See: toadstone toad's-eye Eng. Shelly pink limestone in the Corbula Beds of the Purbeck Beds at Durlston Bay. So called because it is full of the small gastropods Pachychilus manselli that resemble eyes when seen in transverse section. CF: rabbit-eye toad's-eye tin A reddish or brownish variety of cassiterite in botryoidal or reniform shapes with internal concentric or fibrous structure. toadstone a. Applied earlier to various stones or stonelike objects likened in color or shape to toads (batrachites, bufonites, crapodius). Syn: toadrock; fiery dragon. Arkell b. Eng. A kind of traprock. c. An old Derbyshire name for amygdaloidal basalt lava in the Carboniferous Limestone. d. A fossilized object, such as a fish tooth or palatal bone, once thought to have formed within a toad and frequently worn as a charm or an antidote for poison. Syn: toadrock tobacco rock A term used in the Southwest United States for a favorable host rock for uranium, characterized by light yellow or gray color and by brown limonite stains. AGI tobermorite An orthorhombic mineral, Ca9 Si12 O30 (OH)6 .4H2 O ; the principal cementing compound in Portland cement. toddite A mixture of columbite and samarskite. todorokite

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A monoclinic mineral, (Na,Ca)0.5 (Mn,Mg)6 O12 .4H2 O ; forms black spongy banded and reniform aggregates composed of minute lathlike crystals; in Hokkaido, Japan. toe a. The base of the coal, ore, or overburden face in a quarry or opencast mine. Nelson b. The front end of a frog, opposite the heel, in a car track. c. The lowest part of a slope or cliff; the downslope end of an alluvial fan. AGI toeboard A raised edging around the perimeter of a work platform in drilling to prevent hand-tools from being accidentally kicked or knocked off the platform. Long toe cut In underground blasting, the cut obtained by the use of single cut holes inclined downward. Lewis toehole A blasting hole, usually drilled horizontally or at a slight inclination into the base of a bank, bench, or slope of a quarry or open pit mine. toeing-in A quarry term for the wedging-in of the end of a granite sheet under an overhanging joint, probably in consequence of the faulting of the sheets along the joint. It is also applied to the overlapping of lenticular sheets. Fay toe of a shot The distance from the inner end of the hole to the adjacent free face measured at right angles to the direction of the hole; or that portion of the hole that is filled with powder; or that part of the seam to be broken lying between the powder and a free face. Zern toernebohmite See: tornebohmite toe-to-toe drilling The drilling of large-diameter blasting holes in quarries and opencast pits. They are put down vertically from top to bottom of the quarry face. Deck loading is often adopted, 3318

with half to two-thirds of the total charge at the bottom and the remainder in one or more deck charges as required. Nelson to gauge a. Made to gauge, or a size as specified, esp. as applied to the outside set diameter of bits and reaming shells and the inside diameter of a borehole. Long b. To determine, by measurement or other test, the capacity, quantity, or dimension. Long toggle action Application of crushing force so that the distance moved diminishes without change of input strength, between gape and set. Thus greatest speed of movement of the approaching faces is applied with weakest thrust and vice versa. Pryor, 4 toggle joint A joint having a central hinge like an elbow, and operated by applying the power at the junction of motion, as from horizontal to vertical, and giving enormous mechanical advantage; a mechanism common in many forms of presses and in stone crushers. Standard, 2 toggle mechanism A mechanism utilized to apply heavy pressure from a small applied force, such as in a jaw breaker, and other machinery. Hammond toise An old French unit of length used in early geodetic surveys and equal to 6 French ft, 6.396 U.S. ft, or 1.949 m. AGI tolerance A specified allowance (either plus or minus) of the given dimensions of a finished product to take care of inaccuracies in workmanship of parts to be fitted together. The amount allowed as tolerance is generally small as compared with the standard dimension of the part; e.g., the tolerance allowed in the set diameters of a diamond bit is + or -0.02 mm. Long tolerance limits In control of a measured value in a process, limited drift from optimum or norm (e.g., pH 7.6 + or - 0.2). Pryor, 3 3319

toll Ches. Royalty on rock salt, or other mineral. Fay toll enrichment A proposed arrangement by which uranium owned privately could be enriched in uranium-235 content in U.S. Government facilities upon the payment of a service charge. Lyman toll refining Situation in which the owner of ore or concentrate contracts the refining of the metal to another party for a fee, but the refined metal remains under the original ownership for final sale or disposition. tom a. An inclined trough in which gold-bearing earth or gravel is crudely washed; usually called long tom because it is longer than the rocker. Webster 2nd b. Cumb. A parting of black shale in a coal seam. Arkell Tomassi process An electrolytic process for refining lead in which the electrolyte is a solution of a double acetate of lead and potassium or sodium. The anodes are cast from crude argentiferous lead, and the cathodes are in the form of large disks of copper or aluminum bronze and are about half immersed in the electrolyte. Fay tommy bar A short rod used as a lever or handle for turning a jackscrew or a spanner by being inserted loosely in the hole provided for that purpose. Long tomography A division of radiography dealing with the photography of a particular plane in an object while leaving out undesired detail in other planes. Although this technique was developed for medical radiography, it is recommended for certain purposes in work with metals where it is essential that the location of faults be exactly known. Osborne ton-cap screen Commercial brand of wire screen cloth with long rectangular meshes. Pryor, 3 3320

tone a. That attribute of a color that determines its position in a scale from light to dark. Thus white, and also light gray, are light tones, and dark gray is the dark tone of the same color sensation; pink is a light tone of red, and maroon a dark tone. A light tone is usually known as a tint, a dark tone as a shade. See also: intensity b. A monochromatic frequency of vibration, such as in a violin string or vibrations of bodies of finite size and shape. tong die A hard, replaceable, serrated metal insert in pipe tongs, which comes in contact with and grips the outside of a pipe, casing, or drill rod. Also called tong key. Long tongs One of the various tools or wrench devices that can be made to fit and grasp drill rods, casing, or drivepipe. Long tongue a. A branch or offshoot of a larger intrusive body. See also: epiphysis Syn: apophysis b. A minor lithostratigraphic unit of limited geographic extent, being a subdivision of a formation or member, and disappearing laterally (usually by facies change) in one direction; a member that extends outward beyond the main body of a formation. CF: lentil c. A lava flow that is an offshoot from a larger flow; it may be as much as several kilometers in length. AGI tongue joint In welding, a split joint formed by inserting a wedge-shaped piece into a corresponding split piece and welding the two together. Fay tongue plate An adjustable plate that controls the quantity of feed entrapped by the rolls of a doubleroll press. BS, 5 tongue test A test by which crystals and crystalline gemstones can be distinguished from glass that feels warmer in comparison when held to the tongue because of its lower thermal conductivity. tonite 3321

A blasting explosive consisting of a mixture of guncotton with a nitrate and sometimes a nitro compound. Webster 3rd ton-kilometer A unit of measurement often used for the work done in transport. The number of tonkilometers is the weight in tons of material transported multiplied by the number of kilometers driven. Stoces Ton MPH A system that permits calculating how hard an earth-moving tire should work and how much work it is doing. The Ton MPH for any tire is determined by multiplying the mean load and average speed. The resulting figure provides an index to the work a tire is doing. The system enables the operator to determine which type of tires to use to get top performance without overheating. Coal Age, 3 tonnage factor Cubic feet of ore per ton in deposit. Pryor, 3 tonnage man In anthracite coal mining, a person who is paid at a certain rate per ton of coal mined. DOT ton of refrigeration The extraction of 200 Btu/min (211 kJ/min), 12,000 Btu/h (12.7 MJ/h), or 288,000 Btu/d (3.1 GJ/d). The last is also called a ton-day of refrigeration. A ton of refrigeration is equal to 3.5168 kW of heat removal. Strock, 2 Tonpilz machine An apparatus for measuring damping values. Osborne tonstein A compact argillaceous rock containing the clay mineral kaolinite in a variety of forms together with occasional detrital and carbonaceous material; commonly occurring as a thin band in a Carboniferous coal seam (or locally in the roof of a seam); often used as an aid in correlating European strata of Westphalian age. AGI tool box 3322

See: powder box tool box miner A lazy miner, specif. one who rests on a tool box while another miner does the work. Korson tooldresser The driller's helper on a cable tool rig. Syn: cable-tool dresser; toolie. AGI tool extractor An implement for grasping and withdrawing drilling tools when broken, detached, or lost in a borehole. A fishing tool. Also called tool grab. Long tool grinder In stonework industry, one who grinds the cutting tools for stoneworking planers and lathes to a keen edge of the desired shape. DOT tool heat treater One who hardens and tempers tools, dies, and fixtures. toolie A worker who sharpens churn-drill bits; a dresser. See also: tooldresser toolmaker A worker skilled in the making of jigs, fixtures, gauges, etc. Crispin tool nipper A person who carries powder, drills, and tools to the various levels of a mine and brings dulled tools and drills to the surface. Fay toolpusher a. The head driller or drill foreman. Long b. The general supervisor of operations on a drilling rig. More commonly used in petroleum drilling. AGI toolstone 3323

Industrial diamond used for wire-drawing dies, indentor points, shaped-diamond tools, glaziers, and dressers. Toolstones approach gem diamonds in perfection, although not in color. The finer grades may be identical with diamonds sold as low-grade gems. The lower grade toolstones are also sometimes used as drill diamonds. CF: drill diamond Long tooth a. Steel projections on a tool, such as a saw or excavation bucket, designed to provide a cutting or increased digging action. b. A projection on the circumference of a wheel (gear), designed to engage corresponding projections on another wheel (cog), and thereby transmit force. tooth base a. The inner part of a two-piece tooth on a digging bucket. Nichols, 1 b. Occasionally, the socket in which a tooth fits. Nichols, 1 tooth brake A brake used to hold a shaft by means of a tooth or teeth engaging with fixed sockets. Not used for slowing or stopping. Nichols, 1 toothed roller bit See: roller bit toothed-shoe cutter A drivepipe or casing shoe with a serrated or toothed cutting edge. Long tooth turquoise Odontolite; fossil tooth material. too wet A mine-safety expression used to describe those mines or areas of mines that are too wet to propagate explosions even though they are not rock dusted. Too wet is when water exudes from a ball of dust when it is squeezed in the hands. top

3324

a. The surface around a mine shaft; the outside. Jones, 1 b. A mine roof; the upper part of a coalbed separated from the rest by a seam or parting. Fay c. The apex of a vein. Hess d. See: cap; blue cap; overburden. top and apex The words top and apex as applied to mineral veins were not a part of the miner's terminology prior to the adoption of the U.S. Mining Law of 1872, but were words used by legislators to convey the intent of the formulators of that law. CF: apex topaz A triclinic mineral, Al2 (F,OH)2 SiO4 ; pseudo-orthorhombic; colorless to pale blue, pale yellow to pinkish-beige ("sherry" topaz); defines hardness 8 on the Mohs scale; in cavities in granites, granite pegmatites, and rhyolites, and in surrounding metamorphic rocks; may be of gem quality. CF: false topaz; Scotch topaz; Spanish topaz. topazfels See: topazite topazite A hypabyssal rock composed almost entirely of quartz and topaz (Johannsen, 1920). Syn: topazfels; topazoseme; topaz rock. AGI topazolite A yellow variety of andradite resembling topaz. topazoseme See: topazite topaz-quartz See: gold topaz topaz rock See: topazite top bed

3325

Eng. Often applied to the highest bed in a quarry. In Dorset and Somerset, the upper division of the Inferior Oolite. Arkell top benching The method by which the bench is removed from above, as with a dragline. See also: benching top brick Fireclay brick for use in lining the top section of a blast furnace. ARI top cager A worker at the top of a shaft to superintend the operation of lowering and raising of a cage. At most mines, duties include removing loaded cars from the cage and placing empty cars on the cage. See also: cager Fay top canch That part of a mine roof that has to be taken down to give headroom on roadways. Fay top crystals Standard grade of diamonds. Hess top cut a. A machine cut made in the upper limit of the workable section of a coal seam. See also: overcut b. A horizontal cut or groove made in coal at or near the top of the working face. See also: middle cut; bottom cut. topcutter A cutting machine designed esp. for cutting through the seam at a high level above the footwall. Stoces top frame A frame set at or just below ground level as a preliminary to the main timbering in an excavation. See also: setting top gate

3326

A gate road at the upper end of an inclined longwall conveyor face; usually a tailgate. See also: bottom gate top heading A method of driving used for adits, tunnels, and drifts. The upper part or top heading is driven to the full length, before the enlargement of the rest of the section is carried out. Fraenkel top holes An earlier system of working coal between two levels in an inclined coal seam. The top holes are driven to the full rise, and the face-line is usually stepped. Only the coal is worked, and no ripping is done in the top holes. The coal gravitates into trams in the lower level. See also: stepped longwall top hooker See: lander tophus See: tufa top kick See: top shot top lander See: lander top lease A lease granted by a landowner during existence of a recorded mineral lease that is to become effective if and when the existing lease expires or is terminated. Williams topman In mining, a worker who is employed at surface jobs around the mine plant. topographic contour An imaginary line on the ground, all points of which are at the same elevation above (or below) a specified datum surface. AGI 3327

topographic correction See: terrain correction topographic map A map showing the topographic features of a land surface, commonly by means of contour lines. It is generally on a sufficiently large scale to show in detail selected manmade and natural features, including relief, and such physical and cultural features as vegetation, roads, and drainage. CF: planimetric map topographic profile See: profile topographic quadrangle Map upon which is shown a portion of land having elevations indicated by a series of separate lines, each of which passes through a specified elevation; the sinuosity and spacing or crowding together of the contour lines, as they are called, indicate slope and relief of the terrain. topographic unconformity a. The relationship between two parts of a landscape or two kinds of topography that are out of adjustment with one another, due to an interruption in the ordinary course of the erosion cycle of a region; e.g., a lack of harmony between the topographic forms of the upper and lower parts of a valley, due to rejuvenation. AGI b. A land surface exhibiting topographic unconformity. AGI topography a. The general configuration of a land surface or any part of the Earth's surface, including its relief and the position of its natural and manmade features. CF: relief b. The natural or physical surface features of a region, considered collectively as to form; the features revealed by the contour lines of a map. In nongeologic usage, the term includes manmade features (such as are shown on a topographic map). AGI c. The art or practice of accurately and graphically delineating in detail, as on a map or chart or by a model, selected natural and manmade surface features of a region. Also, the description, study, or representation of such features. Etymol: Greek topos, place, + graphein, to write. AGI topotaxy

3328

A recrystallization in which the crystallographic orientation of the parent crystal determines that of the product crystal, e.g., goethite to hematite with a -> c/3, b -> 2 a, and c#M# -> a T3/3. CF: epitaxy; syntaxy. topping a. The contents of a loaded mine car above water level. Hudson b. Fine material forming a surface layer or dressing for a road or grade. Nichols, 1 c. A finishing layer of fine concrete, usually 2 in (5.1 cm) thick, laid over the base concrete of a ground floor or over the structural components of a solid or hollow suspended floor or roof. Hammond toppings Eng. The first regular layers of flints in the Brandon flint mines. Arkell top ripping Roof ripping. Nelson top rod Scot. The rod connecting the uppermost pump rod to the bellcrank (lever) on a bellcrank drive. Fay top shot An explosion or puff of gas at a furnace top. Syn: top kick topside a. On the surface as opposed to underground. Long b. Above the drill rig in the derrick or tripod. Long c. The inlet end of the hydraulic cylinder of a hyraulic-feed mechanism on a diamond drill. Long top slice A horizontal block of ore extracted by top slicing. The dimensions vary in different mines. Nelson top slicing A method of stoping in which the ore is extracted by excavating a series of horizontal (sometimes inclined) timbered slices alongside each other, beginning at the top of the orebody and working progressively downward; the slices are caved by blasting out the timbers, bringing the capping or overburden down upon the bottom of the slices that 3329

have been previously covered with a floor or mat of timber to separate the caved material from the solid ore beneath. Succeedingly lower slices are mined in a similar manner up to the overlying mat or gob, which consists of an accumulation of broken timbers and lagging from the upper slices and of caved capping. See also: block caving top slicing and caving See: top slicing and cover caving top slicing and cover caving A mining method that entails working the orebody from the top down in successive horizontal slices that may follow one another sequentially or simultaneously. The whole thickness of the slice is worked. The ore may be broken by overhand or underhand stoping in each unit. The overburden or cover is caved after mining a unit. Syn: mining ore from top down; top slicing and caving; transverse slicing with caving. Fay top slicing combined with ore caving A method of working an orebody from the top down in successive slices. Instead of taking the full height of the slices, only the lower part is taken and the upper part is caved. After removing this portion of the ore, the cover is caved. A timber mat is used in most cases to separate the broken cover from the ore and for safety. Also known as caving system subdrifting and caving; subslicing; slicing under ore with back cave; sublevel caving; sublevel slicing. Fay top testing See: roof testing top wall See: hanging wall top water Water introduced with the raw coal feed to assist the transport of material through the washbox. Also called transport water. CF: flush water tor A high, isolated crag, pinnacle, or rocky peak; or a pile of rocks, much jointed and usually granitic, exposed to intense weathering, and often assuming peculiar or fantastic shapes, e.g., the granite rocks standing as prominent masses on the moors of Devon and Cornwall, England. AGI 3330

Torbane Hill mineral See: torbanite torbanite a. A variety of algal or boghead coal from Torbane Hill, Scotland. It is layered, compact, brownish-black to black in color, very tough, and difficult to break. On distillation, torbanite gives a high yield of oil. Also called bathvillite. See also: bitumenite; boghead cannel; boghead coal; boghedite; kerosine shale. Syn: Torbane Hill mineral Tomkeieff b. A dark-brown variety of cannel coal. c. An oil shale mined in South Africa. Beerman torbernite A tetragonal mineral, Cu(UO2 )2 (PO4 )2 .12H2 O ; autunite group; strongly radioactive; green; in tabular or foliated crystals, associated with other uranium minerals; commonly in parallel growth with autunite; a secondary mineral resulting from alteration of uraninite. Also called chalcolite, copper uranite, cuprouranite. Syn: uranmica; uranphyllite. CF: metatorbernite torch An oil-burning, wick-fed, miners' lamp of tin or copper, with a long spout. Fay torendrikite A monoclinic mineral, (Na,Mg,Fe)7 Si4 O11 (OH,F) approx.; an amphibole intermediate between richterite and glaucophane; dark blue; at Itorendrika, Madagascar, and near Tine, Wadai, Africa. torf dolomite See: coal ball torf-dopplerit See: dopplerite tormentor a. A wooden axle, studded with iron spikes, for puddling auriferous clay as it spins or turns in a trough. See also: puddler b. A device somewhat similar to a log washer. Fay Tornado 3331

The Tornado crusher is based on the principle of central impeller shoes spinning to hurl particles of gravel against breaker plates at tremendous speed. The impact literally "explodes" the rock, causing it to cleave across the grain as well as with the grain, producing the most desirable cubical product. Pit and Quarry tornebohmite A monoclinic mineral, (Ce,La)2 Al(SiO4 )2 (OH) ; weakly radioactive; green to olive; in contact zones at Bastnaes, Sweden. Also spelled toernebohmite. torpedo An encased explosive charge that is slid, lowered, or dropped into a borehole and exploded to clear the hole of obstructions or to open connections with passage ways to an oil or water supply. Also called a bullet. Long torque The effectiveness of a force that tends to rotate a body; the product of the force and the perpendicular distance from its line of action to its axis. AGI torque bar Square or vertically fluted bar run on one type of auger drill to rotate, raise, and lower the auger. See also: torque rod torque converter A hydraulic coupling that utilizes slippage to multiply torque. Nichols, 1 torquemeter A device for measuring the actual torque transmitted to the drilling head and/or to the drill-rod string. Long torque rod A bar having the function of resisting or absorbing twisting strains. Syn: torque bar torque thickener Tank thickener in which bottom rakes rise when overloaded with settled material. Pryor, 3 torr 3332

The pressure exerted per square centimeter by a column of mercury 1 mm high at a temperature of 0 degrees C where the acceleration of gravity is 980.665 cm/s2 . Hy torrents Beds of quicksand encountered below the chalk marl in the Anzin Coalfield, in France. torreyite A monoclinic mineral, (Mg,Mn)9 Zn4 (SO4 )2 (OH)22 .8H2 O ; related to mooreite and lawsonbauerite; at Sterling Hill, NJ. torsional center If a twisting couple is applied at a given section of a straight member, that section rotates about some point in its plane. This point, which does not move when the member twists, is the torsional center of that section. It is sometimes defined as though identical with the flexural center, but the two points do not always coincide. Syn: center of twist; center of torsion; center of shear. CF: flexural center; elastic center; elastic axis. Roark torsional shear test A shear test in which a relatively thin test specimen of solid circular or annular cross section, usually confined between rings, is subjected to an axial load and to shear in torsion. In-place torsion shear tests may be performed by pressing a dentated solid circular or annular plate against the soil and measuring its resistance to rotation under a given axial load. ASCE torsion anemometer See: Ree's torsion anemometer torsion balance A geophysical prospecting instrument that is used to determine distortions in the gravitational field. It consists of a pair of masses suspended by a sensitive torsion fiber and so supported that they are displaced both horizontally and vertically from each other. A measurement is made of the rotation of the suspended system about the fiber; the rotation is caused by slight differences in the gravitational attraction on the two masses. Syn: Eoetvoes torsion balance torsion break

3333

A break in the drill core caused by an accumulation of chips at the bit face. When drilling is stopped to rechuck, these chips grip the core, and the core is twisted and broken. CF: torsion fracture torsion fracture A spiraled crack in a drill core caused by torque in a blocked bit or core barrel. CF: torsion break torsion seismometer A seismograph with which the horizontal component of the earthquake can be defined making use of the torsion of a vertical suspension thread on which a stationary mass is fastened offcenter. Schieferdecker tortoise Sometimes applied by miners to structures such as pots, bells, kettles, and other rock masses that tend to fall easily from the roof of a coal mine. See also: pot bottom; camel back. AGI tortuous flow See: turbulent flow tossing The operation of raising the grade or purity of a concentrate by violent stirring, followed by packing, in a kieve or open dolly tub. Chimming is a similar process on a smaller scale. See: tozing total acidity Acidity to phenolphthalein. Total acidity of mine water indicates the complete capacity of water to produce chemical change by acid reaction. It is the total amount of acid held in solution or the sum of the quantities of both the ionized and the un-ionized portions of actual acid and the potential quantity of acid that can be formed from mineral salts held in solution. Total acidity is customarily reported in equivalent parts per million (ppm) by weight of calcium carbonate. The indicated total acidity of mine water found by currently accepted methods of analysis generally is greater than the actual total acidity. Felegy total ash

3334

Residue of the mineral matter obtained by incinerating coal under standard conditions. BS, 5 total bit load A drilling term describing the total amount of any load or pressure, expressed in kilograms, pounds, or tons, that is applied to a bit when it is in use. Long total cap lag A blasting term describing the total time between application of current and the detonation. Streefkerk total carbon The sum of the free and combined carbon (including carbon in solution) in a ferrous alloy. ASM, 1 total cooling effect The difference between the total heat content of the air-steam mixture entering a conditioner per hour and the total heat of the mixture leaving per hour. Strock, 2 total cooling load The sum of the sensible and latent heat components that must be removed from a space to maintain desired conditions. Hartman, 2 total critical load a. The total load or pressure that must be applied to a bit for its optimum rate of penetration in a specific rock. Long b. The maximum load that can be applied to a bit without causing damage to the bit. CF: critical pressure total displacement See: slip total dynamic head The total of the static head (the suction discharge heads), the friction head, together with any discharge head that must be overcome by a pump is termed the total dynamic head. Carson, 1 total energy 3335

The total energy at any section in a moving fluid consists of the sum of the internal static, velocity, and potential energies at that section. Hartman, 2 total hardness See: hardness total hardness of water All waters contain two forms of hardness, i.e., temporary (or carbonate) hardness, and permanent (noncarbonate) hardness. The combination of the two is referred to as total hardness. See also: hard water Nelson total head The sum of the elevation head, pressure head, and velocity head of a liquid. For ground water, the velocity-head component is generally negligible. AGI total heat a. The total heat of atmospheric air is the heat contained in the same amount of dry air (known as sensible heat) plus the latent heat of the contained water vapor plus the sensible heat of the water vapor above the wet-bulb temperature. This is called the sigma function or sigma heat. True total heat or enthalpy is the sigma heat plus the heat of the water below the wet-bulb temperature. The latter is a very small quantity, and in mining work sigma heat is always used. Sigma heat is usually measured above 0 degrees F (-18 degrees C), so that it is the heat that would be given up if all moisture were condensed out and removed and the air cooled to 0 degrees F. Some engineers use 32 degrees F (0 degrees C) as the basic temperature so care should be taken to verify the base used. If absolute total heat is specified, it is measured above absolute zero (-459 degrees F or 273 degrees C). Spalding b. The sum of sensible heat and latent heat in a substance or fluid above a base point, usually 32 degrees F or 0 degrees F. Strock, 2 total lift In an air lift, the distance water is elevated during pumping. Total lift equals drop plus static head plus elevation. Also called lift. Lewis total magnetic intensity The vector resultant of the intensity of the horizontal and vertical components of the Earth's magnetic field at a specified point. Hy total moisture 3336

a. Free moisture plus moisture in air-dried coal, both being expressed as percentages of the sample as received. BS, 5 b. The moisture in the coal or coke as samples. BS, 1 total of correctly placed material The sum of the weights of material correctly included in the products of a sizing or density separation, expressed as a percentage of the weight of the feed to the separator (and equal to 100 minus the "total of misplaced material"). BS, 5 total of misplaced material The sum of the weights of the misplaced material in the products of a sizing or density separation, expressed as a percentage of the weight of the feed. When three products are made in a single separator, the total of misplaced material will be the sum of the weight of material wrongly placed in each of the three products, expressed as a percentage of the feed to the separator. BS, 5 total porosity See: porosity total pressure a. The total ventilating pressure in a mine, usually measured in the fan drift. Nelson b. The algebraic sum of static pressure and velocity pressure at any particular point. BS, 8 c. The pressure in a soil mass due to overlying material and any superimposed loads. Nelson d. The pressure on any horizontal plane in a mass of soil as calculated from the weight of the material above the plane, or the soil together with any applied loads. Hammond total reflection In gemology and optical mineralogy, total reflection occurs in a transparent solid where a light ray strikes the surface of a medium of lower refractive index at any angle greater than its critical angle as defined sin r = 1/n, where r is the critical angle and n is the refractive index of the solid (or n2 /n1 , where n1 represents the lower refractive index if other than 1 for air). CF: critical angle; reflection; law of refraction. total reflectometer An instrument for measuring the critical angle in a transparent solid. total resistance

3337

The total resistance (R) or friction of a ventilation system is calculated from the total ventilating pressure (P) and the total quantity of air at the fan (Q). Thus: R= P/Q2 . Nelson total stress The total force per unit area acting within a mass of soil. It is the sum of the neutral and effective stresses. ASCE total tonnage Tonnage of ore or product shipped plus tonnage of ore, waste, and tailings dumped. Hoover total value Value of ore or product shipped plus value of the ore, waste, and tailings dumped. Hoover total ventilating power The sum of the natural ventilating power plus the effective (or air) horsepower of all fans in series. When the circuit is divided and fans are in parallel, the total ventilating power of each split is worked out separately, the natural and fan powers being added; finally the power of each circuit is summed to give the total ventilating horsepower. Spalding total ventilating pressure The pressure required to overcome the static and potential energy head losses and to provide the velocity head to move a quantity of air through a network. See also: ventilating pressure; mine total head; fan total head; water gage. Totco test A test to determine the deviation of a well from the vertical, employing an instrument known as a Totco. Williams touchstone A black, flinty stone, such as a silicified shale or slate, or a variety of quartz allied to chert or jasper, whose smoothed surface was formerly used to test the purity or fineness of alloys of gold and silver by comparing the streak left on the stone when rubbed by the metal with that made by an alloy of predetermined composition. Syn: Lydian stone; basanite. AGI 3338

tough The exact state or quality of texture and consistency of refined copper. See also: tough cake tough cake Refined or commercial copper. See also: cake copper; tough. Fay toughness a. A property of a material that denotes, nominally, an intermediate value between softness and brittleness. Tensile tests show a tough material to have a fairly high tensile strength accompanied by moderate values of elongation and reduction of area. Henderson b. The amount of work required to deform a body to its rupture point. AGI toughness index The ratio between the index of plasticity and the flow index of a soil. Hammond toughness of refractories Resistance to crumbling, to abrasion, or to coarse particles being dislodged from the brick structure. tough pitch a. A term used in electrolytic copper refining to designate copper that has set, from the molten condition, with a level surface. See also: underpoled copper; overpoled copper. Fay b. A term applied to copper in which the oxygen content has been correctly adjusted at 0.03% to 0.06% by poling. Distinguished from overpoled and underpoled copper. CTD tough pitch copper Copper containing from 0.02% to 0.05% oxygen, obtained by refining copper in a reverberatory furnace. ASM, 1 tough tom Soft tenacious clay floor of coal seams. Arkell tough way

3339

A quarryman's term for the third easiest direction of rock fracture after the rift and the grain. Syn: hard way tour A work-shift. Sometimes incorrectly spelled tower. Long tourmaline a. Any member of the trigonal mineral group, XY3 Z6 (BO3 )3 Si6 O18 (OH,F)4 where X is Na partially replaced by Ca, K, Mg, or a vacancy, Y is Mg, Fe2+ , Li, or Al, and Z is Al and Fe3+ ; forms prisms of three, six, or nine sides; commonly vertically striated; varicolored; an accessory in granite pegmatites, felsic igneous rocks, and metamorphic rocks. Transparent and flawless crystals may be cut for gems. b. The mineral group buergerite, dravite, elbaite, ferridravite, liddicoatite, schorl, and uvite. tourmalinization Introduction of, or replacement by, tourmaline. AGI Toussaint-Heintzmann arch A channel-type, steel-arch support consisting of three elements or sections set close to the face of a tunnel. These elements overlap and yield by sliding one upon the other under the constraint of bolted clamps. The center or crown element is usually foreset to give temporary protection until the complete arch is erected. See also: Usspurwies arch; steel arch; steel support. Nelson tow conveyor An endless chain supported by trolleys from an overhead track or running in a track at (above, flush with, or under) the floor with means for towing trucks, dollies, or cars. towed grader See: grader tower a. See: tour b. A misnomer for derrick and an incorrect spelling of tour. Long tower crane

3340

A swing-jib or other type of crane mounted on top of a tower, the base of which may sometimes move on rails. These cranes are esp. effective on congested sites. See also: monotower crane; swing-jib crane. Hammond tower engineer In anthracite coal mining, one who operates a hoist to raise loaded mine cars from the surface of a mine to the top of the breaker, where the coal is dumped, crushed, and prepared for market. DOT tower excavator A cableway excavator designed specif. for levee work, but which is used extensively in the stripping of overburden, spoil, or waste in surface mining. The unit is basically an excavator with towers either fixed or movable. With the headtower located on the spoil pile and the tail tower on the unexcavated wall, it is possible to dig pits of almost unlimited width. tower loader A front-end loader whose bucket is lifted along tracks on a more or less vertical tower. Nichols, 1 Towers magnetic stirrer A device utilizing a rotating field of magnetic force to induce a vigorous rotary movement in a small magnetized bar totally enclosed in a polythene or glass tube, and placed in the liquid to be stirred. Osborne township The unit of survey of the U.S. Public Land Survey system, representing a piece of land that is bounded on the east and west by meridians approx. 6 miles (9.6 km) apart (exactly 6 miles at its south border) and on the north and south by parallels 6 miles apart, and that is normally subdivided into 36 sections. Townships are located with reference to the initial point of a principal meridian and base line, and are normally numbered consecutively north and south from a base line (e.g., township 14 north indicates a township in the 14th tier north of a base line). The term township is used in conjunction with the appropriate range to indicate the coordinates of a particular township in reference to the initial point (e.g., township 3 south, range 4 west indicates the particular township that is the 3rd township south of the base line and the 4th township west of the principal meridian controlling the surveys in that area). Abbrev. (when citing specific location): T. AGI township line 3341

One of the imaginary boundary lines running east and west at 6-mile (9.6-km) intervals and marking the relative north and south locations of townships in a U.S. public land survey. CF: range line toxic dusts Dusts poisonous to body organs, tissue, etc. They include ores of beryllium, arsenic, lead, uranium, radium, thorium, chromium, vanadium, mercury, cadmium, antimony, selenium, manganese, tungsten, nickel, and silver (principally the oxides and carbonates). Hartman, 2 toxicity symptoms In geochemical exploration, a collective term for the abnormal colors and morphological features of a plant caused by a poisonous element in the nutrient solution. Hawkes, 1 toxic mine drainage Water that is discharged from active or abandoned mines or other areas affected by mineral exploration or surface mining and reclamation operations that contains a substance that through chemical action or physical effects is likely to kill, injure, or impair biota commonly present in the area(s) to which it might be exposed. tozing See: tossing trace a. A concentration of a substance that is detectable, but too minute for accurate quantitative determination. AGI b. A quantity of precipitation that is insufficient to be measured by a gauge. AGI c. A sign, evidence, or indication of a former presence; specif. a mark left behind by an extinct animal, such as a trace fossil. AGI d. The record of the output of one geophone group with time after the shot, displayed on paper, film, or magnetic tape. AGI e. The intersection of a geological surface with another surface, e.g., the trace of bedding on a fault surface, or the trace of a fault or outcrop on the ground. CF: trend; strike. AGI f. A very small quantity of a chemical constituent or component, esp. when not quantitatively determined because of extremely low concentrations. g. To follow the lode on the surface, and to lay it open by long pits. Fay h. Recording on the seismogram of a single seismometer station. Schieferdecker trace-by-trace plotting A procedure used in seismic reflection where reflection times from all traces, or sometimes alternate traces, are plotted at the reflecting point positions (midway between 3342

shot and detector). When no correction has been made for "normal moveout," the plotted times appear to lie along arcs that are convex upward and straddle the shot positions symmetrically. CF: center-trace time trace element a. An element that is not essential in a mineral, but that is found in small quantities in its structure or adsorbed on its surfaces. Although not quantitatively defined, it is conventionally assumed to constitute significantly less than 1.0% of the mineral. Syn: accessory element; guest element. AGI b. An element that occurs in minute quantities in plant or animal tissue and that is essential physiologically. Syn: minor element; microelement. AGI tracer An element or compound that has been made radioactive so that it can be followed (traced) easily in industrial and biological processes. Radiation emitted by the tracer (radioisotope) pinpoints its location. Abbrev., tcr. Lyman; Zimmerman tracer gas A gas introduced in small quantities into the main body of air to determine either the air current or the leakage paths in a ventilation system. BS, 8 tracer-gas technique This method, as applied for the measurement of airflow in headings, can be used for determining velocities below the working range of the vane anemometer. The tracer used is normally nitrous oxide. The technique consists of releasing a quantity of tracer gas, either instantaneously or over a timed interval. The tracer then diffuses throughout the airstream until a position is reached where it is uniformly dispersed over the cross section of the airway. At such a position, samples are taken and these are put through the analyzer to determine the gas concentration. Roberts, 1 tracer test In ground water hydrology, a field technique for estimating transport parameters by injecting a tracer (e.g., dye, radioactive substance, or chemical not naturally present in the flow system) and monitoring the time and concentrations at a downgradient location. Domenico trace slip In a fault, that component of the net slip that is parallel to the trace of an index plane, such as bedding, on the fault plane. See also: trace-slip fault 3343

trace-slip fault A fault on which the net slip is trace slip, or slip parallel to the trace of the bedding or other index plane. AGI trachyandesite An extrusive rock, intermediate in composition between trachyte and andesite, with sodic plagioclase, alkali feldspar, and one or more mafic minerals (biotite, amphibole, or pyroxene). See also: mugearite AGI trachybasalt An extrusive rock intermediate in composition between trachyte and basalt, characterized by the presence of both calcic plagioclase and alkali feldspar, along with clinopyroxene, olivine, and possibly minor analcime or leucite. Approx. synonymous with hawaiite. AGI trachyte A group of fine-grained, generally porphyritic, extrusive rocks having alkali feldspar and minor mafic minerals (biotite, hornblende, or pyroxene) as the main components, and possibly a small amount of sodic plagioclase; also, any member of that group; the extrusive equivalent of syenite. Trachyte grades into latite as the alkali feldspar content decreases, and into rhyolite with an increase in quartz. Etymol: Greek trachys, rough, in reference to the fact that rocks of this group are commonly rough to the touch. AGI trachytic a. A textural term applied to volcanic rocks in which feldspar microlites of the groundmass have a subparallel arrangement corresponding to the flow lines of the lava from which they were formed. CF: trachytoid; pilotaxitic. AGI b. Pertaining to or composed of trachyte. AGI trachytoid A textural term originally applied to phaneritic igneous rocks by analogy with the trachytic texture of some lava flows. In such rocks (e.g., many nepheline syenites), the feldspars have a parallel or subparallel disposition; trachytoid is now used for all similar textures, regardless of the composition of the rock in which they occur. CF: trachytic AGI tracing float

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A process in which float is followed back to its origin. A prospector moves up slope looking for pieces of float until no more are to be seen. If, at this point, no outcrop is visible, the probabilities are that soil or loose surface material covers a hidden outcrop, which can be sought by digging pits or trenches. Lewis track a. The groove cut in a rock by a diamond inset in the crown of a bit. Long b. A pattern applied to setting diamonds in a bit crown, in which the diamonds are arranged in concentric circular rows so that the diamonds in a specific row follow the track cut by a preceding diamond. Long c. The slide or rack on which a diamond-drill swivel head can be moved to positions above and/or clear of the collar of a borehole. Long d. See: conveyor track e. A crawler track. Nichols, 1 track bolt A chair bolt or coach screw used in fastening rails. Hammond track braking Track brakes, similar to those used on surface tramcars, may be installed on heavy downgrades underground to supplement other braking systems; they apply blocks to the rails by mechanical, pneumatic, or electromagnetic power. The normal shoe brake must be designed to work in conjunction with the track brakes so that the wheels are not skidded when the track brakes utilize part of the weight of the locomotive. Electromagnetic track brakes may utilize the braking currents produced in rheostatic braking to excite the electromagnets, which are then pulled down onto the rails and produce a strong retarding pull. Sinclair, 5 track cable Steel wire rope, usually a locked-coil rope that supports the wheels of the carriers of a cableway. Hammond track cable scraper This type of excavator operates in general the same as a slackline cableway, except that it uses a bottomless scraper bucket that must convey its load over the ground instead of through the air. Like the slackline cableway, this machine is operated by a two-drum hoist that controls a track cable that spans the working area and a haulage cable that leads to the front of the bucket. Both cables are reeved through sheave blocks attached to a high guyed mast or tower at the head end of the installation. When the bucket comes in with a load and reaches the desired dumping point, a few rotations of the rear drum of the hoist serve to tighten the track cable and lift the bucket off its load; then the brake is 3345

released on the front drum that controls the haulage cable, permitting the empty bucket and carrier to glide back down the inclined track cable. Pit and Quarry track channeler In quarrying, a rock channeler designed to operate from a track on which it is mounted; frequently a combined locomotive and channeling machine. Standard, 2 track cleaner In mining, a laborer who cleans mine track and switches by shoveling coal, ore, rock, mud, and refuse, and throwing it to one side or loading it into a mine car. Also called road cleaner. DOT track cleaners A machine to remove gob from railroad tracks, between rails, and to a distance of 48 in (1.2 m) from the track centers. Digger plates remove gob to the top of ties, while wings on either side of the machine gather it from the sides of the track into the track, to be moved by conveyors to a car at the machine's rear. One person operates the towing motor and observes the digging, while another controls the digging plate height, adjusts wing plows, and observes loading. Best, 1 track diamonds Diamonds set in the face or lead portion of the drill-bit crown. Syn: track stones track frame In a crawler mounting, a side frame to which the track roller and idler are attached. Also called truck frame. Nichols, 1 track gage a. The distance between the inside edges of installed railway rails. BCI b. The minimum track gage that should be used on a modern haulage system is 3 ft 6 in (1.07 m). This gage has been established as a standard by the American Mining Congress as a result of the consensus of opinion of mining engineers and manufacturers in the United States. Wheeler, H.R. c. See also: rail gage track haulage Movement or transportation of excavated or mined materials in cars or trucks running on rails. 3346

tracklaying tractor A tractor moving on crawler tracks. Hammond trackless mine A mine with no rails. In such mines, rubber-tired vehicles operate independently of tracks and are used for haulage and transport. Stoces trackless tunneling A method of tunneling using loaders mounted on crawler tracks, and a diesel- or batterypowered dump-truck haulage system. See also: rubber-tired haulage track-mounted Referring to the operation of equipment on tracks, such as track-mounted cutting machines, track-mounted loaders, etc. Jones, 1 track-moving machine operator In metal mining, one who operates a machine that moves and lays track mechanically in open pit mines, picking up a section of track and moving and laying it in the desired position without having to detach rails from ties. Also called track-laying machine operator. Syn: hydraulic jack operator track pin A hinge pin connecting two sections or shoes of a crawler track. Nichols, 1 track resistance The total rolling friction of a train on straight level track. It is generally taken as 30 lb per short ton weight (15 kg/t) of the train for cars having plain bearings and 20 lb/st (10 kg/t) for cars with roller bearings. These figures may be increased by 10 to 15 lb (5.0 to 7.5 kg) if the track is in poor condition and may be less for track in excellent condition. Lewis track roller In a crawler machine, the small wheels that are under the track frame and that rest on the track. Also called truck rollers. Nichols, 1 track shifter 3347

A machine or appliance used in shifting a railway track laterally. Also the operator of such a device or machine. See also: shifter track spike A heavy steel nail of square section that is driven into a wooden sleeper to hold a flanged rail. Hammond track stones See: track diamonds track wheel One of a set of small flanged steel wheels resting on a crawler track and supporting a track frame. Nichols, 1 traction a. The act of drawing a vehicle over a surface and the force exerted in so doing. Traction is the friction developed between tracks or tires and the surface of the ground on which they are moving. Carson, 1 b. The total amount of driving push of a vehicle on a given surface. Nichols, 1 tractive efficiency A measure of the proportion of the weight resting on tracks or drive wheels that can be converted into vehicle movement. Nichols, 1 tractive effort a. The effort exerted by a locomotive at the rim of its driving wheels; it is a function of its weight, the nature of its tires, and the condition of the track. It is equal to the weight of the locomotive times the adhesion of the locomotive to the track. For steel wheels on clean dry track the adhesion is 25%, and the tractive effort is therefore 500 lb/st of weight (250 kg/t). For cast-iron wheels the adhesion is 20%. Lewis b. The necessary drawbar pull plus the resistance of the locomotive itself. Kentucky c. See: tractive force tractive force a. The pull exerted by a haulage rope on the drawbar of a car to overcome the frictional resistance of the car and the force of gravity acting on it. Also, the force available at the wheels of a locomotive to move the machine and its attached load. Syn: tractive effort b. The pull that a locomotive is capable of producing at its drawbar. Hammond c. In hydraulics, drag or shear developed on the wetted area of a streambed, acting in the 3348

direction of flow. As measured per unit of wetted area, unit tractive force equals the specific weight of water times hydraulic radius times slope of channel bed (Chow, 1957). AGI tractive power The weight of the vehicle multipled by the coefficient of traction; it is the total pounds of pull that can be exerted before slippage occurs. Carson, 1 tractive resistance The resistance to motion due to friction per unit weight hauled. Hammond tractor A self-propelled vehicle--which may be mounted on crawler tracks, on wheels with large pneumatic tires, or on a mixture of both--intended for moving itself and other vehicles. See also: wheeled tractor; mine tractor. Hammond tractor drills These drills have a crawler mounting that supports the feed guide bar on an extendable arm. Small air motors control the movements of the arm used in tilting and turning the guide bar and provide power for crawler movement. The compressor is a separate unit, which can be towed by the tractor drill. Also called a Jumbo. tractor loader A tractor equipped with a bucket that can be used to dig, and to elevate to dump at truck height. Also called tractor shovel; shovel dozer. Nichols, 1 tractor pan operator In beneficiation, smelting, and refining, one who scrapes up bauxite ore from stockpiles, hauls the ore to the crusher, and dumps it into the crusher hopper, using a combination bulldozer carryall. DOT tractor shovel One of the names applied to a class of excavating equipment that has a bucket supported from the front end of a tractor. See also: loader Carson, 1 traffic marks

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Abrasions that result from metal to metal contact and vibration during transit. These abrasions are usually dark in appearance because of the presence of a dark powder, which consists of aluminum and aluminum oxide fines produced by the abrasive action of surfaces rubbing together. Light Metal Age trailer a. A towed carrier that rests on its own front and rear wheels. Also called full trailer. Nichols, 1 b. See: drag trailing cable a. A cable for carrying electricity from a permanent line or trolley wire to a movable machine, such as used in mining or quarrying. The cable is heavily insulated and protected with either galvanized steel wire armoring, extra stout braiding hosepipe, or other material. It is usually paid out from a reel as the machine advances. See also: individually screened trailing cable b. A flexible insulated cable used for transmitting power from the main power source, such as a trolley wire, nipping station, or junction box, to a mobile machine. It includes cables between the nipping station and distribution center. trailing cable coupler An assembly of two restrained-type sockets for coupling together two trailing cables fitted with restrained plugs. BS, 13 trail of a fault Crushed material of a bed or vein that indicates the direction of fault movement; it may be valuable as a guide to the main vein. See also: drag ore train A number of empty or loaded mine cars, coupled together, for transport by rope haulage or locomotive. See also: journey train dispatcher See: motor boss training face Usually a longwall coal face where new colliery entrants or trainees can gain experience, skills, and confidence in the winning and working of coal. Nelson 3350

training gallery A short tunnel or chamber attached to a rescue station in which rescue workers may receive training in an atmosphere of dense smoke. It is also used to give rescue workers experience in stretcher drill, the use of stretchers, reviving apparatus, tube-breathing apparatus, artificial respiration, etc. Nelson training the belt Adjusting the troughing idlers, return idlers, or tail or head pulleys forward or back so that conveyor belting will run in the desired position on the conveyor frame to prevent spilling of ore. Trainite The trade name for a mixture of vashegyite with a colloidal zeolitic mineral, used as a gemstone; originates near Manhattan, NV. Originally described as banded variscite. Syn: Sabalite trainman In metal mining, a laborer who loads ore into railroad cars. DOT train-mile One mile (1.6 km) traversed by one train; used as a unit in railroad accounting. Webster 3rd train of rolls A series of mills, one after the other, each successive mill approaching more nearly the size of the finished piece. Mersereau, 2 train resistance The grade resistance plus the track resistance. Kentucky trajectory Line that intersects wave fronts at right angles. Schieferdecker tram a. A trip of coal cars. Jones, 1 b. Generally, to move a self-propelled piece of equipment other than a locomotive; tramcar. BCI c. A boxlike wagon of steel, running on a 3351

tramway or railway in a mine, for conveying coal or ore. Also called tramcar, tub, cocoa pan, corve, corf, or hutch. CTD; Webster 3rd d. To haul or push trams or cars about in a mine. Fay e. A four-wheeled truck to carry a tub, corve, or hutch. Fay tramcar Eng. A car used in coal mines. Syn: tram tramlines a. An overfill appearing as two parallel lines on rolled bars. Osborne b. Long, straight marks due to drawn-out inclusions on rolled sheet. Osborne trammel a. A board with two grooves intersecting at right angles, in which the two ends of a beam compass can slide and describe an ellipse. Hammond b. See: beam compass c. A pivoted rod, used to keep brick in alignment in lining circular kilns. trammer a. A person who loads broken rock on tramcars and delivers it at the shaft. Fay b. Trammers work as assistant miners in all the work a miner does. They load the broken mineral onto shaker or belt conveyors, fill and haul the mine cars, bring in the mine timber and other materials to support and equip the mine workings, serve the mining and transport machines, and work also as auxiliary mine timbermen. Stoces c. One who transports coal, ore concentrate, or flux to roasting furnaces or bins. DOT tramming The practice of pushing tubs, mine cars, or trams, by hand. Tramming was an earlier practice in longwall stall mining, but is now largely obsolete. On the surface, tramming means moving material in skips or wagons running on light railway track. Nelson tramming motor a. An electric locomotive used for hauling loaded trips. Jones, 1 b. The motor in a cutting machine that supplies the power for moving or tramming the machine. Jones, 1 tramp iron a. Stray metal objects, such as coal-cutter picks or bolts, that have become mixed with the run-of-mine coal or ore. Nelson b. Any loose piece of metal in a borehole. Long tramp oversize 3352

Ore that is too large to be handled efficiently by the machine into which it is fed. Pryor, 3 tramrail Eng. A rail for a tram. A light railroad rail distinguished from tram plate by being rolled while the latter is cast. Webster 3rd tramroad A mine haulage road. Jones, 1 tram rope A hauling rope, to which cars are attached by a clip or chain, either singly or in trips. Zern tram vibrator See: vibrating platform tramway a. A roadway having plates or rails on which wheeled vehicles may run. Syn: tramroad b. A suspended cable system along which material, such as ore or rock, is transported in suspended buckets. See also: aerial tramway c. A system in which carriers are supported by cable and in which the movement is continuous over one or more spans. transcurrent fault A large-scale strike-slip fault in which the fault surface is steeply inclined. Syn: transverse fault; transverse thrust. See also: strike-slip fault transducer a. A device actuated by one transmission system and supplying related waves to another transmission system; the input and output energies may be of different forms. Ultrasonic transducers, e.g., accept electrical waves and deliver ultrasonic waves, the reverse also being true. ASM, 1 b. A device that measures physical quantities in a system--such as ground displacement, velocity, or acceleration-- and converts them into related or proportional units of electronic outputs (e.g., voltage, current). CF: geophone transfer

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A vertical or inclined connection between two or more levels; used as an ore pass. Nelson transfer car a. A quarry car provided with transverse tracks on which the gang car may be conveyed to or from the saw gang. Fay b. A car equipped with rails, used to transfer a drier or kiln car from one set of tracks to another. ACSG, 2 transfer case A transmission or gearset that provides drive to secondary drives, winches, etc. transfer chute A chute used at a transfer point in a conveyor system. The chute is designed with a curved base or some other feature so that the load can be discharged in a centralized stream and in the same direction as the receiving conveyor. Nelson transfer conveyor Conveyor generally 50 to 300 ft (15 to 90 m) in length. It is used to transport material only from one conveyor to another. NEMA, 2 transfer-gang-car system A system used in quarries to save time in handling stone blocks and slabs. In this system, a transfer car that runs on a depressed track in front of the gangs is provided with a short section of track across the top. A gang car loaded with marble, sandstone, etc., is placed on this track and when moved to proper position is shifted beneath the gangsaw. Similarly, a gang car loaded with sawed slabs may be quickly moved from beneath the saws to the transfer car for transportation to the shops. AIME, 1 transfer gear Self-actuating mechanism at shaft head by which a skip is emptied and its contents moved away to the next stage of handling. Pryor, 3 transfer impedance a. The transfer impedance of a network made up of a source and a load connected by a transducer is the ratio of the phasor representing the source voltage to the phasor representing the load current of the load. Hunt b. The complex-valued ratio of voltage at one pair of terminals to the current at another pair in a four-terminal network. AGI 3354

transfer point The point where coal or mineral is transferred from one conveyor to another. See also: loading point transfer table A table connected with rolling mills for laterally transferring work from one mill to the other. Mersereau, 2 transformation A constitutional change in a solid metal; e.g., the change from gamma to alpha iron, or the formation of pearlite from austenite. CTD transformation temperature The temperature at which a change in phase occurs. The term is sometimes used to denote the limiting temperature of a transformation range. transformed flow net A flow net whose boundaries have been properly modified (transformed) so that a net consisting of curvilinear squares can be constructed to represent flow conditions in an anisotropic porous medium. ASCE transformist A proponent of the theory that all granites had a metasomatic or palingenic origin. CF: magmatist AGI transfusion The entry and exit of any gaseous or hydrothermal fluid in solid rock to produce such rocks as granite. CF: granitization transgranular See: intracrystalline transgression a. The spread or extension of the sea over land areas, and the consequent evidence of such advance (such as strata deposited unconformably on older rocks, esp. where the new marine deposits are spread far and wide over the former land surface). Also, any 3355

change (such as rise of sea level or subsidence of land) that brings offshore, typically deep-water environments to areas formerly occupied by nearshore, typically shallowwater conditions, or that shifts the boundary between marine and nonmarine deposition (or between deposition and erosion) outward from the center of a marine basin. Ant: regression. CF: onlap marine transgression. AGI b. A term used mostly in Europe for discrepancy in the boundary lines of continuous strata; i.e., unconformity. See also: unconformity AGI transgressive overlap See: onlap transient velocity A velocity, different from the steady state velocity, which a primer imparts to a column of powder to start detonation. transistor A device for controlling or amplifying electric currents by means of potential probes through a crystal of a semiconductor, commonly silicon or germanium. transit a. A theodolite in which the telescope can be reversed (turned end for end) in its supports without being lifted from them, by rotating it 180 degrees or more about its horizontal transverse axis. AGI b. The act of reversing the direction of a telescope (of a transit) by rotation about its horizontal axis.---v. To reverse the direction of a telescope (of a transit) by rotating it 180 degrees about its horizontal axis. Syn: plunge Transite A trade name for a material of asbestos fiber and Portland cement molded under high pressure. Used for fireproof walls, roofing, and in lining ovens, etc. Crispin transition belt A short belt carrying material from a loading point to a main conveyor belt. Nichols, 1 transition curve a. A curve designed to effect a gradual change between a straight and a circular curve. Hammond b. See: spiral curve transition elements 3356

a. In the periodic system, those elements characterized by the increment of inner d shells of electrons which may become involved in secondary or hybrid bond formation. b. Elements having atomic numbers 21 (Sc) to 30 (Zn), 39 (Y) to 48 (Cd), and 57 (La) to 80 (Hg). transition metals Elements in the middle of the long periods of the periodic table. Usage varies, but most commonly the transition elements are taken to include those from scandium to zinc in the first long period, from yttrium to cadmium in the second, and from lanthanum to mercury (excluding the 14 rare-earth metals from cerium to lutecium) in the third. AGI transition point A single point at which different phases of matter are capable of existing together in equilibrium. Syn: inversion point transition temperature The temperature at which the change from tough to brittle fracture occurs in a notched bar impact test, or sometimes in other forms of test, e.g., notched tensile test. Syn: inversion point transitman One who operates a surveyor's transit. The person need not necessarily be a graduate engineer. Crispin translational fault A fault in which there has been translational movement and no rotational component of movement; dip in the two walls remains the same. It can be strictly applied only to segments of faults. Syn: translatory fault AGI translational movement Apparent fault-block displacement in which the blocks have not rotated relative to one another, so that features that were parallel before movement remain so afterwards. CF: rotational movement See also: translational fault AGI translation lattice See: crystal lattice translatory fault 3357

See: translational fault translucency A term used to describe mineral crystals sufficiently transparent to transmit light. Also called subtransparency. CF: transparency Pryor, 3 translucent The optical property of a mineral to transmit light without objects being visible. CF: opaque translucent attritus This term was first used by R. Thiessen in 1930 referring to the attritus of ordinary humic coal, which is ordinarily composed largely of transparent humic matter, with spores, cuticles, resins, and opaque matter in minor proportions. Translucent attritus consists of the complex residual organic matter, exclusive of anthraxylon, in bituminous lower rank coal that transmits light in thin section. The following macerals of the Stopes-Heerlen nomenclature are included in translucent attritus: vitrinite less than 14 mu m thick; sporinite; cutinite; alginite; resinite; and those parts of semifusinite, micrinite, and sclerotinite that are weakly reflecting, that is semitranslucent. Translucent attritus is a collective term and is not comparable with any of the microlithotypes of the European system of nomenclature. IHCP translucent glass Glass that will admit rays of light to pass but through which objects cannot be seen. Mersereau, 2 translucent humic degradation matter Transparent humic matter consisting of irregular particles varying greatly in shape and size. Although rounded or ovoid particles are not rare, humic matter is mostly flattened in form and usually of frayed or tattered appearance. The particles are of the same deep red color as the anthraxylon strips, becoming lighter in thinner sections. Syn: THDM IHCP transmissibility Term used to describe the ability of a system either to amplify or to suppress an input vibration. It is the ratio of the response amplitude of the system in steady-state forced vibration to the excitation amplitude. The ratio may be between forces, displacements, velocities, or accelerations. Hy 3358

transmission A mechanism that provides a variety of gear ratios for different load conditions, speed, or direction of rotation. transmission reversing A transmission that has only a forward and reverse shift. Nichols, 1 transmissometer An instrument that measures the capability of a fluid to transmit light; esp. one that measures the turbidity of water by determining the percent transmission of a light beam. See also: turbidimeter transmittance Rate of heat flow per unit area per unit temperature difference. Strock, 2 transmitted light Light that has passed through an object, as distinguished from light reflected from a surface. The nonopaque minerals in rocks are commonly studied in transmitted planepolarized light for characterization and identification by use of a polarized-light microscope. Gems are usually examined for imperfections by transmitted light. CF: birefringence; index of refraction. transmutation The transformation of one element into another. Radioactive decay is an example. Transmutation can also be accomplished by bombardment of atoms with high-speed particles. AGI transmute In alchemy, the transformation of baser metals into more precious metals. Gordon transopaque The property of a mineral to transmit light in part of the visible spectrum while being opaque in another. CF: opaque transparency

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a. The degree to which visible light is transmitted through a solid. A mineral is termed transparent if objects can be clearly seen through it, as through glass; e.g., rock crystal (quartz), selenite (gypsum), Iceland spar (calcite), and gem diamond. Syn: diaphaneity opaque. b. The capacity of seawater to transmit light; the depth to which water is transparent may be measured by use of a Secchi disc. c. A positive image, either black and white or in color, on a clear base (glass or film), intended to be viewed by transmitted light; a diapositive. transparent a. Permitting the passage of electromagnetic radiation. b. Things that may be seen through; e.g., rock crystal (quartz), Iceland spar (calcite), selenite (gypsum). CF: opaque transparent glass Glass through which objects can be seen. Mersereau, 2 transponder An automated receiver and/or transmitter for transmitting signals when triggered by an interrogating signal. Hy transport a. A mining term used to cover vehicular transport, hydraulic transport, and conveyors. See also: conveyor; haulage; hydraulic pipe transport. Nelson b. Syn: transportation occurs in combined terms such as sediment transport and mass transport. AGI transportable equipment Machines or equipment that can be moved from one part of a mine to another by mechanical means, such as but not by self-propulsion, on a track, or on attached wheels. See also: mobile equipment transportable substation A transformer equipped with switchgear and mounted upon wheels or skids. Syn: portable substation transportation a. In geology, the shifting of material from one place to another on the Earth's surface by moving water, ice, or air. The carriage of mud and dissolved salts by rivers, the passage of a dust-laden whirlwind across a desert, the inland march of sand dunes from a seashore, and the creeping movement of rocks on a glacier are all examples of 3360

transportation. See also: transport b. The hauling or moving from one place to another of material, such as ore, coal, rock, etc. Fay transport controller A person stationed in a central position, at a large opencast pit or quarry, to observe all the excavations. By means of signals, the individual is informed when and where vehicles or cars are required and can instruct the lorry or locomotive drivers accordingly. Nelson transported gossan Some transported gossans are simply colluvial accumulations of fragments of normal gossan that have moved down the slope from the site of weathering. Another variety of an entirely different origin is effectively a fossil spring or seepage deposit, where at one time iron-rich ground water has precipitated massive limonite at or near the daylight surface. Hawkes, 2 transport number In electrolysis, a proportional fall in the number of ions concentrated at an electrode n=loss of concentration at cathode, and/or loss at cathode and anode. This phenomenon is caused by differences in the rate of travel of various species of ion. Pryor, 3 transuranic a. Of, or pertaining to, radioactive substances produced by bombarding uranium with neutrons. Bennett b. Having an atomic number higher than that of uranium; having an atomic number higher than 92. Webster 3rd Transvaal emerald See: African emerald Transvaal garnet A green garnet, possibly grossular or a variety of andradite. transverse fault A fault that strikes obliquely or perpendicular to the general structural trend of the region. See also: transcurrent fault transverse gallery 3361

An auxiliary crosscut made in thick deposits across an orebody for the purpose of dividing it into sections along strike. It is used only a short time and runs across the thickness of the deposit only. Stoces transverse joint A joint that is transverse to the strike of the strata or schistosity. transverse loading The loading on a beam. Hammond transverse pitch The lateral distance between the center lines of each strand of a multiple-strand chain, or between the tooth profiles on a sprocket for a multiple-strand roller chain. Jackson, 1 transverse riffles See: Hungarian riffles transverse slicing with caving See: top slicing and cover caving transverse strength a. A measure of the capability of a stone bar (or beam) supported at its ends to bear a weight or load at its center. Fay b. The strength of a specimen tested in transverse bending; normally synonymous with modulus of rupture but also used to refer to breaking load. Taylor transverse thrust See: transcurrent fault transverse trace A trace on the ground motion record representing the component of motion in a horizontal plane at a right angle to the seismic wave travel direction. transverse ventilation See: peripheral ventilation 3362

transverse wave a. In seismology, a wave motion in which the motion of the particles, or the entity that vibrates, is perpendicular to the direction of progression of the wave train. AGI b. In geophysics, a body seismic wave advancing by shearing displacements. AGI c. A wave in which the direction of propagation of the wave is normal to the displacements of the medium; e.g., a vibrating string. The gravity wave in which fluid parcels move in circular orbits is an example of a mixed transverse-longitudinal wave. The Rossby wave is also mixed, except in the case of zero current speed, when it is a transverse wave. Syn: distortional wave; secondary wave. See also: S wave transverse with filling See: overhand stoping trap a. Any dark-colored fine-grained nongranitic rock, such as a basalt, peridotite, diabase, or fine-grained gabbro; also applied to any such rock used as crushed stone. Syn: trapp; traprock; trappide. CF: whinstone AGI b. A device for separating suspended sediment from flowing water; e.g., a sand trap. AGI c. A door used for cutting off a ventilating current and that is occasionally opened for haulage or passage. See also: trapdoor Fay d. A device to separate denser material from less-dense material, such as entrained water in a stream or a compressed-air line. Long e. That portion of any mass of porous, permeable rock that is sealed on top and down the sides by relatively nonporous and impermeable rock and that lies above the intersection of a horizontal plane passing through the lowest point of complete sealing. trap cut A gem with a row or rows of steplike facets around the table and culet (or small lower terminus of the gem, parallel to the table), or around the culet alone. See also: step cut trapdoor a. A door in a mine passage to regulate or direct the ventilating current. Also called weather door. See also: trap b. See: air door trapezohedron a. An isometric crystal form of 24 faces, each face of which is ideally a four-sided figure having no two sides parallel, or a trapezium. Syn: leucitohedron b. A crystal form consisting of six, eight, or twelve faces, half of which above are offset from the other half below. Each face is, ideally, a trapezium. The tetragonal and hexagonal forms may be right- or left-handed. AGI 3363

trapezoid A quadrilateral that has only two sides parallel. Jones, 2 trapezoidal rule A rule for estimating the area of an irregular figure by dividing it into parallel strips of equal width, each strip being a trapezium. See also: Simpson's rule trapp See: trap trapper a. An employee, normally an apprentice, used to open and close mine doors. Also called trapper boy; nipper; door tender; doorman. Syn: door boy BCI; Fay b. An employee who assists the dispatcher by throwing switches and attending telephone at an inside station. BCI trapper boy See: trapper trappide See: trap trap points Points placed on a railway line to derail a train that has been incorrectly signaled. Hammond traprock See: trap trash screen Protective screen for removing detritus from the pulp stream ahead of a processing unit. Pryor, 4 trass

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A common name in the older literature for unwelded massive ash and pumice-flow deposits. Trass has been used in the production of pozzolan cement. CF: ignimbrite traveling angle of draw The angle of draw advancing with a moving face. Nelson traveling apron See: apron traveling block a. The movable unit, consisting of sheaves, frame, clevis, and/or hook, connected to, and hoisted or lowered with, the load in a block-and-tackle system. Also called floating block; running block. Long b. The pulley block that hangs below the crown block and is used for lifting the drilling column. BS, 9 c. A frame for a sheave or a set of sheaves that slides in a track. Syn: traveling sheave traveling compartment The section of a mine shaft used for raising and lowering miners. Stoces traveling gantry A movable gantry built on wheels for traveling on rails and supporting a hoisting device. Hammond traveling road A roadway used by miners for walking to and from the face; i.e., from the shaft bottom or main entry to the workings and back. Syn: traveling way Nelson traveling sheave A sheave block that slides in a track. See also: traveling block Nichols, 1 traveling way See: traveling road traveling weight

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The portion of the overlying strata at the coal face that is supported and controlled by face supports. This weight "advances" as the face line moves forward. See also: underweight traverse a. A sequence or system of measured lengths and directions of straight lines connecting a series of surveyed points (or stations) on the Earth's surface, obtained by or from field measurements, and used in determining the relative positions of the points (or stations). AGI b. A line surveyed across a plot of ground. AGI c. To make a traverse; to carry out a traverse survey. See also: traverse survey d. A vein or fissure in a rock, running obliquely and in a transverse direction. AGI e. A line across a thin section or other sample along which grains of various minerals are counted or measured. AGI traverser A platform superimposed upon or forming part of the rail track that is free to roll or slide sideways so that a car can be moved bodily from one track to another parallel to it. See also: inclined traverser Nelson traverser system The basic idea of this system is to confine the mine-car circuit to the smallest possible compass near the mine shaft. This avoids locking up cars on the surface that are better employed underground and reduces labor requirements. In this system, instead of the use of shunt backs on car circuits, the direction of car travel is changed by running onto a portable platform that then moves the car bodily in a transverse direction. The system can be applied, in conjunction with the necessary lifts, to multideck cages. This system may be operated electrically, hydraulically, or pneumatically. Sinclair, 5 traverse survey A survey in which a series of lines joined end to end are completely determined as to length and direction, these lines being often used as a basis for triangulation. It is used esp. for long narrow strips of land (such as for railroads) and for underground surveys. Syn: traverse AGI traverse tables Published tables giving the differences of latitude and departure for different angles. Hammond traversing method

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One of three recognized methods for determining the average velocity of airflow along a mine roadway by an anemometer. This is the general routine procedure applied when measuring air velocities in mine roadways. While the instrument is running, it is slowly and steadily moved up and down a series of imagined vertical lines, so as to cover equal areas in equal time. The total period is usually 1 min for a medium-sized roadway. The integrated reading is then the mean velocity for that section. CF: division method; singlespot method. Roberts, 1 travertine a. A dense, finely crystalline, massive or concretionary limestone; generally white, tan, or cream; commonly having a fibrous or concentric structure and splintery fracture; formed by rapid chemical precipitation of calcium carbonate from solution in surface and ground waters, such as by agitation of stream water or by evaporation around the mouth or in the conduit of a spring, esp. a hot spring. It also occurs in limestone caves, where it forms stalactites, stalagmites, and other deposits; as a vein filling; along faults; and in soil crusts. The spongy or less compact variety is tufa. See also: cave onyx; onyx; onyx marble. Syn: calcareous sinter; calc-sinter. b. A term that has been applied to any cave deposit or calcium carbonate. c. A term used inappropriately as a syn. of kankar. d. Etymol. Italian tivertino from the old Roman name of Tivoli, a town near Rome, where travertine forms an extensive deposit. Also spelled travertin. Syn: travertine marble travertine marble See: travertine trawley A small truck or car conveying material about a furnace or iron mill; sometimes applied to trucks, in mines, etc. See also: trolley Fay tray a. A car, carrier, or pallet, usually suspended from the moving element of a conveyor. b. A section of gravity conveyor, chain conveyor, or shaker conveyor. See also: pan; trough. Syn: tray carrier tray carrier See: tray tray thickener A drying unit that differs from the ordinary round tank in that it houses several horizontal trays that divide it into compartments. Each has its own set of rakes and its 3367

own underflow for settled material and peripheral overflow. Used where space is limited or in subarctic conditions that call for antifreeze housing. Pryor, 3 tread a. The ground contact surface on a tire or a track shoe. Nichols, 1 b. Occasionally, a high-friction lagging on a belt pulley. Nichols, 1 c. The pit in which brickmakers soak their clay before putting it into the pug mill. Standard, 2 tread tractor A form of locomotive that is serviceable over rough roads. A trailer, with capacity up to 16 yd3 (12.2 m3 ), with bottom discharge or two-way side discharge is used with the tractor. The maximum speed is about 6 m/h. Nelson treasure box A pocket of very rich ore. treated stone A gemstone that has been heated, stained, oiled, or coated; treated by various types of irradiation, in order to improve or otherwise alter its color; or laser-drilled to make flaws inconspicuous. Also, a stone that has been preserved from dehydration, such as an opal whose cracks have been filled with oil or other liquid; or one in which special effects have been produced; e.g., amber with "spangles" (tension cracks). See also: altered stone treatment The reduction of ores by any process whereby the valuable constituent is recovered. Fay treble Three standard lengths of drill rod or drill pipe connected together and handled and stacked in a drill tripod or derrick as a unit length of rod on borehole round trips. Also incorrectly spelled thribble; thrible; tribble; trible. See also: stand; rod stand. Long treble coursing In mining, the system of dividing a ventilating current into three coursings. Standard, 2 trechmannite

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A trigonal mineral, AgAsS2 ; forms minute scarlet-vermillion rhombohedral crystals; at Binenthal, Switzerland. tree a. Visible projection of electrodeposited metal formed at a site of high current density. ASM, 1 b. A thick log used as a prop in heavy ground. A prop, leg, or puncheon. See also: treed c. The fulcrum for the lever used in boring. Fay d. A treelike aggregate of crystals, which forms from solution on a suspended substrate that induces crystallization. Webster 2nd tree agate A moss agate with dendritic markings resembling trees. Syn: tree stone treed Supported by props, such as a mine roof. See also: tree treeling See: trilling treenail A hardwood plug drilled so as to allow a track spike to be driven through it into a timber sleeper. Hammond tree ore A high-grade uranium ore consisting of buried carbon trash that has been replaced or enriched with uranium-bearing solutions. AGI tree stone See: tree agate tremolite A monoclinic mineral, 2[Ca2 Mg5 Si8 O22 (OH)2 ] ; amphibole group with magnesium replaced by iron, and silicon by aluminum toward actinolite; white to green; long-bladed or stout prismatic crystals; may show columnar, fibrous, or granular masses or compact aggregates; in low-grade metamorphic rocks such as dolomitic limestones and talc schists; the nephrite variety is the gemstone jade; the asbestiform variety is byssolite. CF: actinolite 3369

tremolitic Pertaining to or characterized by the presence of tremolite, as tremolitic marble. tremor tract a. An area of intensely jumbled coal and associated beds. The contortions contain sharp folds, thrusts, and glides. The mode or origin is controversial. A theory that has gained some favor is that the disturbance was initiated by a seismic shock, causing the coal seam and beds to crack and heave. Later, lateral forces appear to have produced the final complicated structures. Nelson b. In coal mining, an area of complex folding, faulting, and gliding of coal seams and associated rocks. It may be formed by seismic shocks during the deposit's semicompacted state. AGI trench a. A long, straight, commonly U-shaped valley or depression between two mountain ranges. AGI b. A narrow, steep-sided canyon, gully, or other depression eroded by a stream. AGI c. Any long, narrow cut or excavation produced naturally in the Earth's surface by erosion or tectonic movements. Also, a similar feature produced artificially, such as a ditch dug in prospecting for minerals. AGI d. An elongated but proportionally narrow depression, with steeply sloping longitudinal borders, one of which (the continental) rises higher than the other (the oceanic). Trenches are the ends of unsymmetrical basins and lie beside the continental border or island chains. Syn: marginal trench AGI e. A long but narrow depression of the deep-sea floor having relatively steep sides. AGI f. A long, narrow, intermontane depression occupied by two or more streams (whether expanded into lakes or not), alternately draining the depression in opposite directions. AGI g. A narrow ditch. AGI h. In geological exploration, a narrow, shallow ditch cut across a mineral deposit to obtain samples or to observe character. i. A long, narrow excavation in the ground, as a trench dug for the laying of pipes. Crispin j. A temporary scar in which a conduit is placed and then covered over. CF: ditch trench excavation Excavation in which the width of operations and, generally, the depth are limited. Trenching may be performed in any soil and will sometimes fall into the category of limited-area, vertical excavation. Carson, 1 trench excavator A self-propelled machine generally mounted on crawler tracks designed for digging trenches or ditches. It is equipped with either a bucket ladder or buckets mounted around the periphery of a circular wheel. Hammond 3370

trenchman See: ripper trench sampling A slight refinement of grab sampling in which the material to be sampled is spread out flat and channeled in one direction with a shovel, and the material for the sample is taken at regular intervals along the channel. The procedure is repeated with several other channels in different directions until a sample of the proper size has been secured. Also called channel sampling. Newton, 1 trend a. A general term for the direction or bearing of the outcrop of a geological feature of any dimension, such as a layer, vein, orebody, fold, or orogenic belt. CF: strike b. The direction or rate of increase or decrease in magnitude of the individual members of a time series of data when random fluctuations of individual members are disregarded; the general movement through a sufficiently long period of time of some statistical progressive change. AGI c. The direction or bearing of a bed, dike, sill, etc., or of the intersection of the plane of a bed, dike, joint, fault, or other structural feature with the surface of the ground. Fay d. The direction or bearing of a fold or series of folds in rocks, of the axes of the folds, of subsurface structures, of oriented or elongated structures indicated by geological surveys, or of topographic features that are consequent on the geologic structure. (As used in either sense, the trend may or may not coincide with the strike, depending on the structural relations at the place of observation.) CF: trace Fay trent agitator An agitator with paddle-wheel-type arms; they are hollow, and the pulp solution or air is discharged from nozzles on these arms, thus causing the stirrer to rotate. Liddell Trenton a. A subdivision of the American Ordovician sometimes considered as the equivalent of the whole Middle Ordovician and sometimes restricted to a portion of this series. Webster 3rd b. Formerly, a division of the lower Silurian. Trent process Agglomeration process sometimes used in coal cleaning and briquetting. Raw coal crushed to minus 65 mesh is agitated with water and oil. Coal agglomerates and ashforming fraction are removed in aqueous solution. Pryor, 3 3371

trepan a. A boring tool once used in the Kind-Chaudron shaft-sinking method. Nelson b. A boring machine used for shaft sinking through water-bearing strata. trepanner A cutter loader for continuous mining in longwall faces. Its main cutting unit is the trepanner wheel with cutting arms, one at each end of the machine to enable it to cut in both directions on the face. Also fitted are a vertical, back-shearing jib; a floor-cutting jib, duplicated to enable cutting in either direction; and, if necessary, a roof-cutting disk. The machine is used in conjunction with an armored flexible conveyor on a prop-free front face; suitable for seams between 3 ft and 4 ft (0.9 m and 1.2 m) thick, although it can work in thicker seams if the top coal falls freely. Nelson trepanning A type of boring in which an annular cut is made into a solid material, with the coincidental formation of a plug or solid cylinder. ASM, 1 trepan shearer A cutter loader in which the trepanner head is incorporated into the shearer-loader while the cutting drum is retained to dress the floor and back of the cut. Nelson trespass Working coal from the property or take of another coal mine owner. See also: encroachment trestle a. A bridge, usually of timber or steel, that has a number of closely spaced supports between abutments. Nichols, 1 b. A bent of timber, reinforced concrete, or steel, supporting a temporary or permanent structure. Hammond trestleman Person who unloads coke, limestone, and ore, and keeps bins poked down. Fay tret Allowance to purchaser for waste. Pryor, 3 trevorite 3372

An isometric mineral, NiFe2 O4 ; magnetite series of the spinel group; black with greenish tint; at Barberton, Transvaal, South Africa. triad In crystallography, an element of symmetry characterized by a rotational axis requiring three operations to return to identity. Isometric symmetry contains four diagonal triads; trigonal symmetry requires a unique triad. CF: threefold trial face See: experimental face trial pit A shallow hole, 2 to 3 ft (0.6 to 0.9 m) in diameter, put down to test shallow minerals or to establish the nature and thickness of superficial deposits and depth to bedrock. See also: test pit; pit sampling. Nelson trial shots The experimental shots and rounds fired in a sinking pit, tunnel, opencast, or quarry to determine the best drill-hole pattern to use. This is carried out when hard rocks are exposed. Nelson triamorph A chemical compound crystallizing in three different crystal structures. triangle cut The characteristic feature of this cut lies in the fact that the drill holes are arranged in zigzag. In this way a larger opening is obtained because the drill holes can break out between the preceding rows. Each vertical row of holes breaks out a layer. If the front holes do not break out to the full depth, the burnt-out holes indicate the direction of break for the following row of holes since the holes are arranged in zigzag. The name, triangle cut, is due to the distribution of the holes at the working face and the form of the initial opening. Fraenkel triangle shooting A refraction type of seismic shooting used to facilitate the separation of intercept times into constituent delay times. Three profiles can be laid out as sides of a triangle. If intercept times are obtained at each of the vertices of the triangle from shots at the other two vertices, one can solve for the delay times at the three corners. Delay times along the 3373

sides of the triangle can be determined by taking differentials in the intercept times with respect to the delay times established at the vertices. Dobrin triangular core The strand core of a flattened strand rope. Hammond triangular facet A physiographic feature having a broad base and an apex pointing upward; specif. the face on the end of a faceted spur, usually a remnant of a fault plane at the base of a block mountain. A triangular facet may also form by wave erosion of a mountain front or by glacial truncation of a spur. Syn: spur-end facet triangular method A method of ore reserve estimation based on the assumption that a linear relationship exists between grade difference and the distance between all drill holes. Krumlauf triangular texture In mineral deposits, texture produced when exsolved or replacement mineral crystals are arranged in a triangular pattern, following the crystallographic directions of the host mineral. AGI triangulate To divide into triangles; esp. to use, survey, map, or determine by triangulation. Etymol: back-formation from triangulation. AGI triangulation a. A trigonometric operation for finding the directions and distances to and the coordinates of a point by means of bearings from two fixed points a known distance apart; specif. a method of surveying in which the stations are points on the ground at the vertices of a chain or network of triangles, whose angles are measured instrumentally, and whose sides are derived by computation from selected sides or base lines, the lengths of which are obtained by direct measurement on the ground or by computation from other triangles. Triangulation is generally used where the area surveyed is large and requires the use of geodetic methods. CF: trilateration b. The network or system of triangles into which any part of the Earth's surface is divided in a trigonometric survey. AGI triaxial compression test 3374

A test in which a cylindrical specimen of rock encased in an impervious membrane is subjected to a confining pressure and then loaded axially to failure. See also: unconfined compression test Syn: triaxial shear test triaxial shear test See: triaxial compression test tribe A subdivision of the rock association or kindred. A tribe is made up of clans. See also: rock association tribocouple Two chemically dissimilar metals in mutual electrical contact. The friction produced by the mechanical agitation of the two members of the couple results in the flow of an electric current. The power of a tribocouple is the magnitude of the current that it will generate under specified conditions of friction. Osborne Triboelectrostatic separation process An electrostatic process under development, in which fine-size dry coal is blown rapidly past a copper baffling device that imparts positive triboelectric charges on the coal and negative charges on the associated mineral matter. The material is introduced into an electrostatic separator, where it is separated. triboluminescence a. The property of some specimens of zinc sulfide of emitting sparks when scratched. Fay b. Luminescence in which electrons in a trapped state are released by abrasion or crushing. CF: luminescence tribrach a. Three leveling screws and footplate used to attach a theodolite or surveyor's level to its tripod, level the instrument, and center it precisely over its mark. Pryor, 3 b. The frame below a theodolite on which three foot screws are mounted. See also: limb tribromomethane See: bromoform tribute work 3375

In mining, work on shares. Standard, 2 tributing a. A system under which a syndicate of miners delivers coal at the pithead at an agreed price. This system may be used where ore deposits are too small and scattered to conduct normal mining activities. "Tributors" work and deliver their ore to the owner and receive payment based on the ore's ascertained value. Nelson b. Working on a sharing basis. Pryor, 3 tricalcium pentaluminate A compound, 3CaO.5Al2 O3 , formerly believed to be present in high-alumina hydraulic cement. It is now known that a melt of this composition consists of a mixture of CaO.2Al2 O3 and CaO.Al2 O3 , the latter compound being responsible for the hydraulic properties. Dodd tricalcium silicate 3CaO.SiO2 ; dissociates at approx. 1,900 degrees C to form CaO and 2CaO.SiO2 . This compound is the principal cementing constitutent of Portland cement, small quantities of MgO and Al2 O3 usually being present in solid solution. Tricalcium silicate is also present in stabilized dolomite refractories. Dodd trichalcite A former name for tyrolite. See also: tyrolite trichite A straight or curved hairlike crystallite, usually black. Trichites occur singly or radially arranged in clusters and are found in glassy igneous rocks. AGI trichloroethylene Colorless; stable; low-boiling; heavy; mobile; toxic; liquid; CHCl:CCl2 . CCD, 2 trichroism Characteristic of a crystal showing three different colors in transmitted light; limited to crystallization in the orthorhombic, monoclinic, and triclinic systems. CF: pleochroism; dichroism. trickle drain 3376

A pond overflow pipe set vertically with its open top level with the water surface. Nichols, 1 trickle scale Scale that has become detached from a pack of sheets in pack rolling, trickling in between the pack and becoming embedded in the surface of the sheets during further rolling. Osborne triclinic a. In crystallography, periodicity requiring three crystal axes having no further constraint on the interaxial angles designated alpha, beta, and gamma. b. The least symmetric of the seven (or six) crystal systems, requiring all three axial vectors a, b, and c and three interaxial angles alpha , beta , and gamma as lattice parameters. Of its two crystal classes, one has a center of symmetry and the other does not. Feldspars and axinites crystallize in the triclinic system. Syn: anorthic (obsolete); triclinic system. triclinic block In quarrying, a term applied to a block of stone bounded by three pairs of parallel faces, none of which intersect at right angles. Fay triclinic crystal Crystal having no symmetry elements, or only an inverse center. The typical crystal has three unequal axes, no two of which are perpendicular. Henderson triclinic system See: triclinic tricone bit A roller bit having three cone-shaped cutters in the head of the bit. See also: roller bit tricone roller bit See: tricone bit tridimite See: tridymite tridymite 3377

A monoclinic and triclinic mineral, 4[SiO2 ] ; pseudohexagonal; polymorphous with coesite, cristobalite, quartz, and stishovite; colorless to white; in felsic volcanics and refractories. Also spelled tridimite. Triger process A method of sinking through water-bearing ground in which a shaft is lined with tubbing and provided with an air lock so that work proceeds under air pressure. CF: KindChaudron process trigger circuit A circuit having a number of states of electrical condition (which are either stable or quasi-stable) or that is unstable with at least one stable state and so designed that a desired transition can be initiated by the application of a suitable trigger excitation. By quasi-stable state is meant a state that persists during the time of interest. NCB trigger effect When rock is subjected to increasing stresses there comes a time when it is on the point of failure. In some circumstances it may remain at that point for a considerable time. Any small external influence, such as a seismic wave, may then be sufficient to precipitate the failure. This is known as the trigger effect. Spalding triggers Term applied to any number of things that may initiate or trigger rock bursts. Such triggers include blasting, changes of temperature, sudden influxes of water, and even rock bursts themselves, which sometimes act as a trigger impulse to initiate a second burst. Issacson trigonal a. Describes a crystal form or structure with a unique triad of symmetry. b. A symmetry operation requiring three repetitions to return to identity. Syn: triad c. Characteristic of, pertaining to, or belonging in the trigonal system or in the rhombohedral division of the hexagonal system. (Not all trigonal point groups may be characterized by rhombohedral axes, hence the incongruence between the trigonal system and the rhombohedral division of the hexagonal system.) CF: rhombohedral division; hexagonal system. trigonal coordination In a crystal structure, a cation with three anions around it at the points of a triangle, e.g., C in a CO32- group. 3378

trigonal system In assigning point groups to seven crystal systems, the trigonal system is characterized by a unique triad, that element of rotational symmetry for which three operations of 120 degrees return a lattice to identity. CF: rhombohedral division; hexagonal system. trigonite A monoclinic mineral, Pb3 Mn(AsO3 )2 (AsO2 OH); forms sulfur-yellow triangular wedge-shaped crystals; at Laangban, Sweden. trigonometrical leveling Basically this method consists of determining the vertical heights by measurement of distances and angles of inclination. Angles of inclination are measured either by hand instruments or more accurately by theodolite. Mason trigonometrical survey See: triangulation trigonometry Measurement of three-angled figures, or measurement by use of three-angled figures. Jones, 2 trihydrocalcite A hydrous calcium carbonate, CaCO3 .3H2 O . A moldlike incrustation on chalk marl. From Nova-Alexandria, Poland. English trikalsilite A hexagonal mineral, (K,Na)AlSiO4 ; polymorphous with kaliophilite, kalsilite, and panunzite. trilateration A method of surveying in which the lengths of the three sides of a series of touching or overlapping triangles are measured (usually by electronic methods) and the angles are computed from the measured lengths. CF: triangulation trill See: trilling 3379

trilling A cyclic crystal twin consisting of three individuals. CF: fourling; fiveling; eightling. Syn: treeling; trill. See also: threeling trilobite A primitive, extinct crustacean, occurring throughout the Paleozoic and abundant in the earlier Paleozoic periods, characterized by a segmented body divided by longitudinal grooves into three lobes. trimerite A monoclinic mineral, CaMn2 Be3 (SiO4 )3 . trimetric A solid figure in which the three axes are all unequal, but intersect one another at right angles. Syn: orthorhombic trim holes Unloaded drill holes closely spaced along a line to limit the breakage of a blast. Syn: relief holes trimmer a. A shothole bored slightly outward to trim the drivage to the shape required. Mason b. An apparatus for trimming a pile of coal into a regular form (such as a cone or prism). Webster 3rd c. One who uses a shovel to distribute loose material--such as coal, rubbish, sand, or other substances--in railroad cars or holds of ships and barges during or after loading. May be designated according to material trimmed, such as a coal trimmer. DOT trimmer conveyor A self-contained, light-weight portable conveyor, usually of the belt type, for use in unloading and delivering bulk materials from trucks to domestic storage, and for trimming bulk materials in bins or piles. See also: portable conveyor trimmer holes These complete the breaking out of the ground. The positioning and number of trimmer shots are governed by the size of the drift, the hardness of the ground, and the fragmentation required for the loading-out method to be adopted. McAdam, 2 3380

trimmers a. The shotholes drilled around the periphery of a shaft or tunnel that break or trim the sides of the excavation to the shape and size required. See also: cut holes b. The top row of holes in a tunnel face. Stauffer trimming shed See: mica house trimorphism The property of a chemical compound to crystallize in one of three different crystal structures. CF: dimorphism; polymorphism. trimorphous A chemical compound that may crystallize in one of three different crystal structures. trinascol Dense asphaltic petroleum containing 9% sulfur. Tomkeieff trinitrate glycerol See: nitroglycerin trinitrin See: nitroglycerin trinitrotoluene-ammonium nitrate explosive An explosive containing ammonium nitrate sensitized with trinitrotoluene. A proportion of aluminum powder or calcium silicide may be added to increase power and sensitiveness. Nelson trinkerite A resinous substance occurring in large amorphous masses of a hyacinth-red to chestnutbrown color in brown coal near Albona, Istria (former Yugoslavia). Resembles tasmanite in composition. AGI trioctahedral 3381

Pertaining to a layered-mineral structure of the kaolinite-serpentine, talc-pyrophyllite, mica, or chlorite groups in which all three of the positions with octahedral coordination are occupied, mainly by divalent cations, such as Mg, or by a mix of monovalent and trivalent cations, such as Li and Al. CF: dioctahedral trip a. A small train of mine cars. Korson b. The number of cars moved at one time by a transportation unit. Hudson c. The operation in rotary drilling of pulling out (trip out) and running in (trip in) the drill string, as required to replace a worn bit, extract a core, or recover a fish. Syn: round trip d. An automatic arrangement for dumping cars; a tipper, a kickup. Fay e. A release catch. Nichols, 1 trip change A term used in mine transportation for the period during which the loads (loaded mine cars) are taken away and a fresh trip of empties is brought back. This period is known as trip change in contrast to car change. In this interval a great deal of potential loading time can be lost. Kentucky trip coil A device for opening protective equipment or a circuit breaker, operated by a solenoid. Hammond tripestone a. A mineral form with the outward appearance of tripe or intestines, e.g., stalactitic calcite, crumpled gypsum laminae, contorted concretionary anhydrite, barite. Also spelled tripe stone. b. Stalactite resembling intestines. Arkell c. A variety of gypsum formed of crumpled, alternating laminae of pure white gypsum and gray argillaceous gypsum. Arkell d. A contorted concretionary variety of anhydrite. Fay trip hammer A power hammer operated by a tripping mechanism that causes the hammer to drop. Crispin triphane A former name for spodumene. triphylite

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An orthorhombic mineral, 4[LiFe2+ (PO4 )] , with manganese replacing iron toward lithiophilite; bluish to greenish gray; in granite pegmatites. trip lamp A removable self-contained mine lamp, designed for marking the rear end of a train (trip) of mine cars. triple entry A system of opening a mine by driving three parallel entries for the main entries. See also: main entry triple-entry room-and-pillar mining See: room-and-pillar triple point An invariant point at which three phases coexist in a unary system. When not otherwise specified, it usually refers to the coexistence of solid, liquid, and vapor of a pure substance. AGI triplet An assembled stone of two main parts of gem materials bonded by a layer of cement or other thin substance (the third part of the triplet), which gives color to the assemblage. CF: doublet; emerald triplet. tripletine A name for emerald-colored beryl triplet. See also: emerald triplet triple-tube core barrel A special core barrel used to take soil samples, as in foundation testing. The inner tube is swivel mounted and nonrotating and extends through, and a short distance beyond, the bit. Hence, the bit only cuts clearance for the outer tube or core-barrel assembly, and the core taken by the inner tube is cut by a spudding action. The triple or core tube is mounted inside the inner tube to receive the core and is split longitudinally to facilitate removal of the core. Also called clay barrel. Long Triplex glass A patented form of laminated glass. See also: safety glass 3383

triplexing A method of steelmaking that involves the use of three processes, e.g., a sequence of melting in a cupola, blowing in a Bessemer converter, and finishing in a basic electric furnace, or a combination of the acid Bessemer converter, the basic open-hearth furnace, and the basic electric furnace. Osborne triplex pump A positive-displacement piston pump having three water cylinders mounted side by side. It may be either a single- or double-action type. CF: duplex pump triplite A monoclinic mineral, 8[(Mn,Fe,Mg,Ca)2 (PO4 )(F,OH)] ; brown; forms fibrous masses; in granite pegmatites. Syn: pitchy iron ore triploidite A monoclinic mineral, (Mn,Fe)2 (PO4 )(OH) ; perfect cleavage. trip maker A device to elevate cars on an inclined track as received from a kickback. Zern tripod A three-legged support for a rock drill, hoisting drum, magnetometer, or any other piece of equipment. tripoli See: diatomite tripolite A term that has been applied as a syn. of diatomite, in reference to the material from the north African location of Tripoli. It has also been used, less correctly, as a syn. of tripoli. See also: diatomite AGI tripper a. A device in the run of a conveyor comprising two free drums around which the belt passes S-fashion. Nelson b. A device for discharging material from a belt conveyor. Nelson c. A double pulley that turns a short section of a conveyor belt upside down in 3384

order to dump its load into a side chute. Nichols, 1 d. A device or mechanism that trips, as a device for causing the load on a conveyor to be discharged into a hopper or other receptacle. Webster 3rd e. An automatic car dump. f. A device for tipping and dumping the skip at the top of the blast furnace. Mersereau, 2 tripper man Person who unloads grain or ore from conveyor belt into bins or processing equipment by operating a tripper. Syn: conveyor-operator tripper; conveyor-tripper operator; spreader operator. DOT tripping a. The process of pulling and/or lowering drill-string equipment in a borehole. Long b. To open a latch or locking device, thereby allowing a door or gate to open to empty the contents of a skip, bailer, etc. Long trippkeite A tetragonal mineral, CuAs+32 O4 ; excellent prismatic cleavage permitting crystals to be broken into flexible fibers; blue-green; at Atacama, Chile. trip recorder See: hoist trip recorder trip sender In bituminous coal mining, a laborer who switches cars to various tracks, couples and uncouples trains, and attaches and detaches cars to and from the haulage cable at a mine where there are several sidetracks on the haulageway. DOT tripuhyite A tetragonal mineral, FeSb2 O6 ; forms dull greenish-yellow microcrystalline aggregates; in the cinnabar-bearing gravels of Tripuhy, Ouro Preto, Minas Gerais, Brazil. trisilicate In metallurgy, a slag with a silicate degree of 3. Newton, 1; Newton, 2 trislope screen A screen in which each section of the deck is flatter than the preceding one. The rate of feed is reduced on succeeding sections to maintain proper bed depth for rapid 3385

stratification. It is designed for fine dry screening of 3/4-in (19-mm) by 0-in, 1/2-in (13mm) by 0-in, and 1/4-in (6 mm) by 0-in moist coal or other material. See also: varislope screen Nelson trisoctahedron A crystal form of 24 faces in the isometric system with the gross appearance of each face of an octahedron being replaced by three faces arrayed around a diagonal triad. Each face of a trigonal trisoctahedron is an isosceles triangle, while each face of a tetragonal trisoctahedron is a trapezoid. Syn: trapezohedron trisodium phosphate Na3 PO4 , a chemical compound used in some enamel frit compositions. Enam. Dict. tristetrahedron a. An isometric hemihedron included under 12 trapeziform faces; a tetragonal tristetrahedron. Standard, 2 b. An isometric hemihedron included under 12 isoceles triangular faces; a trigonal tristetrahedron. Standard, 2 tritium The radioactive isotope of hydrogen having two neutrons and one proton in the nucleus. Being hydrogen-3, it is heavier than deuterium (heavy hydrogen or hydrogen-2). Lyman; Handbook of Chemistry and Physics, 2 tritomite A trigonal mineral, (Ce,La,Y,Th)5 (Si,B,Al)3 (O,OH,F)13 (?) ; moderately radioactive; metamict; dark brown; in syenite with leucophanite, analcime, mosandrite, aegirine, and catapleiite. Formerly called spencite. triton value The number of grams of TNT required to produce the same angle of recoil of the ballistic mortar as 10 g of the explosive under test. McAdam, 2 triturate a. A powder produced from a solid by grinding, usually with the addition of some liquid. Gaynor b. To grind to a powder, usually with the addition of some liquid. Gaynor trituration 3386

Reduction to a fine powder by grinding. Syn: comminution CF: levigation trivalent a. Having a valence of 3. Webster 3rd; Standard, 2 b. Having three valences; e.g., chromium, which has valences of 2, 3, and 6. Syn: tervalent troctolite A gabbro that is composed chiefly of calcic plagioclase (e.g., labradorite) and olivine with little or no pyroxene. Such rocks commonly are speckled like trout. Syn: forellenstein; troutstone. AGI troegerite See: troegerite trof-dopplerit See: dopplerite troegerite A very rare tetragonal mineral, H(UO2 )(AsO4 ) .4H2 O ; autunite group; strongly radioactive; lemon-yellow; in veins with walpurgite, zeunerite, uranospinite, pitchblende, and other uranium minerals. Also spelled troegerite. Troeger's classification A quantitative mineralogic classification of igneous rocks proposed by E. Troeger in 1935. AGI trogtalite An isometric mineral, CoSe2 ; pyrite group; dimorphous with hastite; violet. troilite A hexagonal mineral, FeS ; a meteorite mineral related to pyrrhotite, Fe1-x S , in terrestrial rocks. Trojan coal powder High explosive used in mines. Bennett 3387

trolley a. The grooved wheel, fixed in bearings at the end of a trolley pole, pressed upward in rolling contact with the overhead trolley wire to take off the electric current for operating the locomotive or other piece of motorized equipment. A trolley glider is frequently used in place of the wheel, making a sliding contact with the wire. Also called trolley wheel. Jones, 1 b. A low carriage, mounted on wheels, for carrying timber, supplies, and machines underground. See also: trawley; bogie. Nelson trolley conveyor A series of trolleys supported from or within an overhead track and connected by an endless propelling medium, such as a chain, a cable, or other linkage, with loads usually suspended from the trolley. Trolley conveyors may be designed for single or multiple plane operation. Syn: overhead conveyor; overhead trolley conveyor. trolley locomotive a. A mine locomotive operated by electricity drawn from overhead conductors. Small grooved wheels or gliders are held in contact with the conductors, and the current passes down a trolley arm to the motor. It is very efficient where heavy loads are hauled up relatively steep gradients. Generally restricted to intake airways not nearer than 300 yd (274 m) to a working face. Nelson b. A mine locomotive operated by electricity drawn from overhead trolley wires. Nelson trolley voltage Although not actually set by law, the generally accepted maximum direct current trolley voltage is considered to be 300 V. The use of alternating current voltages above 220 V in mines is usually permitted, provided the conductors are properly insulated and the cables end in suitable terminal boxes. Kentucky trolley wire The means by which power is conveyed to an electric trolley locomotive. It is hung from the roof and conducts power to the locomotive by the trolley pole. Power from it is sometimes also used to run other equipment. BCI trolley wire guards Coverings for exposed trolley wires in mines and other locations where transportation power wires are within reaching height and are a constant source of danger to all personnel. Coverings, made of rubber or some other insulating material, guard workers from severe burns or electrocution by direct contact with the wire. Best, 1 3388

trombe An apparatus for producing a blast of air by means of a falling stream of water, which mechanically carries air down with it, to be subsequently separated and compressed in a reservoir or drum below. See also: water blast trommel A revolving cylindrical screen used in size classification of coarsely crushed ore, coal, gravel, and crushed stone. The material to be screened is delivered inside the trommel at one end. The fine material drops through the holes; the coarse material is delivered at the other end. Also called, according to its various uses, sizing trommel, washing drum, and washing trommel. Also spelled tromel. See also: revolving screen; rotary breaker; rotary screen; shaking screen. ASM, 1; Liddell; Standard, 2 trommel screen A screen in which the screening surface is formed into a cylinder or frustum of a cone, mounted upon a rotating shaft or on revolving rollers. See also: revolving screen tromp curve See: ash curve tromp cut point See: partition density Tromp distribution curve A curve showing the float-sink percentage of each density fraction of the feed coal. The quantity of clean coal recovered is plotted against the mean densities of the density fraction. From this curve the specific gravity of separation and the sharpness of the separation can be determined. Such a curve is independent of the coal being washed and is characteristic of a specific coal-washing device. trompe See: trombe tromp error curve See: error curve Tromp process 3389

a. The Tromp process was the first to introduce (about 1938) the use of magnetite suspension in dense-medium washing. The magnetite is ground to about minus 1/250 in (0.1 mm) and added to water. The process makes use of an unstable suspension with horizontal currents of differing densities at intermediate levels. The process operates within the size range 6 to 200 mm and in practice is used for raw coal down to 1/4 in (6.4 mm). It gives a reasonably accurate three-product separation. Nelson b. A densemedium process that utilizes a rapidly settling suspension of finely powdered magnetite or sintered roasted pyrite. This process may be used on any size of coal from 10 to 1/4 in (254 to 6.4 mm) and for any specific gravity from 1.3 to 1.9. The grain size of the magnetite or pyrite is minus 0.1 mm. The quick settling of the magnetite particles gives a higher specific gravity in the lower layers of the wash box, which makes it possible to obtain three products: clean coal, middlings, and refuse. Mitchell trona A monoclinic mineral, Na3 (Co3 ) ((HCO3 )X2H2 O ; soft; vitreous; colorless to white; alkaline tasting; in saline lake deposits and desert soils; a major source of sodium compounds from extensive deposits at Searles and Owens Lakes, CA, and in Wyoming, Hungary, Egypt, Africa, and Venezuela. See also: sodium sesquicarbonate Trona process The method used for the separation and the purification of soda ash (anhydrous sodium carbonate), anhydrous sodium sulfate, boric acid, borax, potassium sulfate, bromine, and potassium chloride from brine at Searles Lake, San Bernardino County, CA. CCD, 2 trondhjemite A light-colored plutonic rock composed primarily of sodic plagioclase (esp. oligoclase), quartz, sparse biotite, and little or no alkali feldspar. Its name, given by Goldschmidt in 1916, is derived from Trondhjem, Norway. Also spelled: trondjemite; trondheimite. AGI trondjemite See: trondhjemite troostite a. A manganoan variety of willemite occurring in large reddish crystals. b. A previously unresolvable, rapidly etching, fine aggregate of carbide and ferrite produced either by tempering martensite at a low temperature or by quenching a steel at a rate slower than the critical cooling rate. Preferred terminology for the first product is tempered martensite; for the latter, fine pearlite. ASM, 1 troostitic structure 3390

Fine aggregates of ferrite and cementite in steel; emulsified ferrite. Pryor, 3 Tro-Pari survey instrument Trade name of a single-shot borehole surveying instrument combining a compass and inclinometer, which is locked in place by the action of a preset time clock. Long tropic pack A special type of packing to protect explosives from deteriorating when subjected to hot, humid atmospheric conditions, such as in tropical areas. The explosives, after being sealed with paraffin, are packed in cartons, which are then wrapped in waxed paper and also sealed with paraffin. The filled cartons are then placed inside a satchel-type case liner of bitumen-laminated paper reinforced with sisal fiber and completely sealed with a waterproof adhesive. Nelson trough a. A channel, open or covered, that contains coal or ore being conveyed on a chain or shaker conveyor. The shape of the cross section depends on the type of conveyor involved. See also: tray b. A hollow or undulation in a mineral field, or in a mineral working. In geology, synonymous with basin; synclinal. See also: graben c. The lowest point of a given stratum in any profile through a fold. CF: trough line d. A line occupying the lowest part of a fold; the line connecting the lowest parts on the same bed in an infinite number of cross sections. See also: trough plane trough banding Rhythmic layering or alignment of minerals in an igneous rock, confined to troughlike depressions and considered to have been produced by currents set up in the magma during cooling. AGI trough conveyor A pan conveyor or gravity conveyor. Nelson troughed belt A belt conveyor in which the carrying side is made to form a shallow trough by means of troughing idlers. Nelson troughed belt conveyor

3391

A belt conveyor with the belt edges elevated on the carrying run to form a trough by conforming to the shape of the troughed carrying idlers or other supporting surface. See also: belt conveyor troughed roller conveyor A roller conveyor having two rows of rolls set at an angle to form a trough over which objects are conveyed. See also: el conveyor trough fault A fault, generally a normal fault, that bounds a graben or other structural depression. AGI troughing a. A structural section shaped like a wide U; riveted or welded to form a bridge deck with the U-shaped sections turned alternately upwards and downwards. Hammond b. Making repeated dozer pushes in one track, so that ridges of spilled material hold dirt in front of the blade. Nichols, 1 c. Eng. In Derbyshire, toadstones filling fissures. troughing idler A belt idler having two or more rolls arranged to turn up the edges of the belt so as to form the belt into a trough. NEMA, 1 troughing rolls The rolls of a troughing idler that are so mounted on an incline as to elevate each edge of the belt to form a trough. NEMA, 1 trough line a. The line occupying the lowest part of the fold, or, more precisely, the line connecting the lowest parts of the same bed in an infinite number of cross sections. CF: trough b. The line joining the trough points of a given stratum. AGI trough plane The plane that joins the troughs of a series of beds in a syncline; generally, but not necessarily, the same as the axial plane. See also: trough trough vein

3392

A trough-shaped ore deposit formed between sedimentary beds in the troughs of synclinal structures. trough washer a. A washer applying the principle of alluviation in troughs. BS, 5 b. In its simplest form, a trough washer is a sloping wooden trough, 1-1/2 to 2 ft (0.46 to 0.6 m) wide, 8 to 12 ft (2.4 to 3.7 m) long, and 1 ft (0.9 m) deep, open at the tail end, but closed at the head end. It is used to float adhering clay or fine material from the coarser portions of ore or coal. A log washer. troutstone See: troctolite trow A wooden channel for air or water. Fay troy ounce One-twelfth of a pound of 5,760 grains (troy pound), or 480 grains. A troy ounce equals 20 pennyweights, 1.09714 avoirdupois oz, or 31.1035 g. It is used in all assay returns for gold, silver, and platinum-group metals. Fay; Zimmerman troy pound A unit of weight that equals 5,760 grains, 12 tr oz, 240 pennyweights, 13.1657 avoirdupois oz, 0.82286 avoirdupois lb, or 373.2509 g. Fay; Zimmerman troy weight These are the weights used for precious metals. The equivalents are 24 grains = 1 pennyweight; 20 pennyweights = 1 oz; 12 oz = 1 lb. The troy grain is the same as the avoirdupois grain, but the ounce is larger on the troy scale; 1 tr oz = 31.103 g; 1 avoirdupois oz = 28.35 g. Anderson truck Any wheeled vehicle, usually self-propelled, used to transport heavy articles or materials. In mining, usually applied to dump and/or bottom-dump semitrailers used to transport mined waste and ore materials. The number of types of these haulage units varies widely from the small 2-st (1.8-t) standard dump truck to the unit with capacity 200 st (181 t) or greater. For larger stripping operations, where the haulage conditions are not too rugged, a diesel tractor pulling a bottom-dump semitrailer of capacity 40 to 3393

60 st (36 to 54 t) is most common. The newer trucks are equipped with power steering, power brakes, torque converters, and automatic transmissions. truck mixer A concrete mixer, generally mounted on a lorry, or crawler-type tracks, which mixes concrete during the journey from the batching plant to the construction site. Hammond truck roller See: track roller trudellite A mixture of chloraluminite and natroalunite. true azimuth The azimuth measured clockwise from true north through 360 degrees . AGI true bearing The bearing expressed as a horizontal angle between a geographic meridian and a line on the Earth; esp. a horizontal angle measured clockwise from true north. CF: magnetic bearing true depth The actual depth of a specific point in a borehole measured vertically from the surface in which the borehole was collared. Syn: true vertical depth true dip a. A syn. of dip, used in comparison with apparent dip. Syn: full dip AGI b. The angle at which veins, strata, etc., dip, as measured vertically downward from the horizon along a line at right angles to the strike of the veins, strata, etc.; also, the dip of a vein, strata, etc., as determined on oriented core. See also: core orientation; oriented core; apparent dip. Long c. The maximum angle which an inclined bed makes with a horizontal plane. It is the direction in which water would flow if poured on the smooth upper surface of the bed at the outcrop. Also called dip. See also: level course d. See: three-dimension dip true lode See: fissure vein 3394

true middlings a. See: bone coal b. Comparatively high-ash material so nearly homogeneous that its quality cannot readily be improved by crushing and cleaning. BS, 5 true strain The integral, over the whole of a finite extension, of each infinitesimal elongation divided by the corresponding momentary length. It is equal to loge (1 + epsilon ), where epsilon is the strain as ordinarily defined. See also: strain true stress For an axially loaded bar, the load divided by the corresponding actual cross-sectional area. It differs from the stress as ordinarily defined because of the change in area due to loading. See also: stress Roark true vein An occurrence of ore, usually disseminated through a gangue of veinstone, and having more or less regular development in length, width, and depth. See also: vein; fissure vein. Fay true vertical depth See: true depth true whiting A finely divided calcium carbonate prepared by wet grinding and levigating natural chalk; a variety of limestone. USBM, 7 true width a. The width or thickness of a vein, stratum, etc., as measured perpendicular or normal to dip and strike. The true width is always the width of the vein, etc., at its narrowest point. CF: apparent width Long b. The true width of a vein in sampling may be found by w = h sin a , where h = horizontal width, w = true width, and a = angle of dip. In this formula, angle a is known from previous observations, and the horizontal width can be measured with a level. It is important that horizontal width is measured at right angles to strike. Hoover truffite

3395

Fibrous nodular lignite which when struck emits an odor like that of truffles. It occurs in large nodular masses inside a normal lignite of Cretaceous age in France. Tomkeieff truing-machine operator One who grinds the surfaces of refractory blocks to reduce them to standard dimensions, using a truing machine. DOT trumpeting Eng. A channel or passage partitioned off from a shaft or left behind the lining, usually running along one corner of the latter. Used for ventilation. Webster 2nd trumpet log See: microlaterolog truncated spur A spur that projected into a preglacial valley and was partially worn away or beveled by a moving glacier as it widened and straightened the valley. See also: faceted spur trunk a. A long, narrow, inclined box in which fine ore is separated from impurities. Fay b. A launder for conveying slimes, etc. Webster 2nd c. To separate slimes by means of a trunk for further treatment. Webster 2nd trunk conveyor A high-capacity main road conveyor, usually a belt conveyor. It may extend from the main inby loading point to the shaft bottom or along levels or drifts to the surface. It varies from 42 to 60 in (1.07 to 1.52 m) wide and is powered by a motor of about 200 hp (149 kW). See also: conveyor; gathering conveyor. Nelson trunkline a. A detonating cord line used to connect the downlines or other detonating cord lines in a blast pattern. Usually runs along each row of blastholes. Dick, 2 b. The line of detonating cord that is used to connect and initiate other lines of detonating cord, used on the ground surface to initiate downlines. trunk pumping engine

3396

A pump that commands the drainage of underground waters over a considerable area of mine workings, being a substitute for a number of smaller, independent pumps. Fay trunk roadway The main development heading from the pit bottom, usually driven along the strike of the coal seam. Because it will carry heavy traffic and large volumes of air, a trunk roadway is at least 14 ft (4.3 m) wide and wide enough for two rail tracks. At intervals, crossheadings are excavated for opening out conveyor panels in the coal seam. Trunk roadways are usually driven in pairs for ventilation, storage space, and access. Nelson trunnion a. Either of two opposite pivots, journals, or gudgeons, usually cylindrical and horizontal, projecting one from each side of a piece of ordnance, the cylinder of an oscillating engine, a molding flask, a converter, etc., and supported by bearings, to provide a means of swiveling or turning. Webster 2nd b. An oscillating bar that allows changes in angle between a unit fastened to its center, and another attached to both ends. Nichols, 1 c. A heavy horizontal hinge. Also called walking beam; walking bar. Nichols, 1 trunnion axis The horizontal axis about which the telescope of a theodolite can be rotated. Hammond trunnion plate A metal plate lining the bearings or recesses in which the trunnions rest. Webster 2nd truscottite A hexagonal mineral, (Ca,Mn)14 Si24 O58 (OH)8 .2H2 O ; in spherical aggregates of white scales; at Benkulen, Sumatra. truss a. An assemblage of members, such as beams, bars, and rods, typically arranged in a triangle or combination of triangles to form a rigid framework, such as for supporting a load over a wide area that cannot be deformed by the application of exterior force without deformation of one or more of its members. Webster 3rd b. A framed structure built up entirely from tension and compression members, arranged in panels so as to be stable under load; used for supporting loads over long spans. CTD trussed beam 3397

A beam of timber or other material that is stiffened so as to reduce deflection. Hammond tsavolite A green gem variety of garnet. Also spelled tsavorite. tscheremchite See: cheremchite tschermakite A monoclinic mineral, Ca2 (Mg,Fe)3 Al2 (Si6 Al2 )O22 (OH)2 ; amphibole group, having Mg/(Mg + Fe) = 0.5 to 1.0 ; forms a series with ferrotschermakite. tsilaisite A synthetic manganese tourmaline or manganoan elbaite. tsumebite A monoclinic mineral, Pb2 Cu(PO4 )(SO4 )(OH) ; brackenbuschite group; in small, tabular, emerald-green crystals; at Tsumeb, Namibia. tub a. A tram, wagon, corf, or corve. CTD b. A small rail-track vehicle for carrying coal or minerals, with a capacity ranging from 10 to 25 hundredweights (453.6 to 1,134 kg). Tub is the term used in most English mines; tram is used in South Wales; and hutch is used in Scotland. Nelson c. A box or bucket in which coal or ore is sent up a shaft. A keeve. Webster 3rd d. To line, such as in a mine shaft, with tubbing; to keep back water by tubbing. See also: tubbing e. A large circular base that provides the maximum practical bearing area, and on which is mounted the revolving frame or subbase of a walking dragline. Austin tub-and-stall See: bord-and-pillar working tubber A double-pointed pickax; a beele. Standard, 2 tubber man 3398

A person who uses a tubber. Standard, 2 tubbing a. The watertight cast-iron lining of a circular shaft built up of segments that are fixed together with flanges. The flanges are internal and bolted in German tubbing; they are external in English tubbing, which gives a smooth inner face because the segments are wedged and not bolted. The space outside the tubbing is grouted to add strength and improve watertightness. See also: tub; suspended tubbing. Nelson b. Eng. A lining of timber or metal for a shaft, as in a mine, esp. a watertight shaft lining consisting of a series of cast-iron cylinders bolted together and used to sink through water-bearing strata. Webster 3rd c. A shaft lining of casks or cylindrical caissons of iron or wood. See also: plank tubbing; wooden tubbing. Fay tubbing wedge A small wooden wedge hammered between the joints of tubbing plates. Zern tube-axial fan An airfoil (propeller) or disk fan within a cylinder and including driving-mechanism supports either for belt drive or direct connection. Strock, 2 tube blower A person who cleans boiler tubes. Fay tube clamp a. A clamp or clip for gripping a tube or pipe; esp., a jawed tool used in hoisting and lowering well tubes in drilling. Standard, 2 b. A misnomer for casing clamp. Long tube mill A revolving cylinder, usually lined with silex, nearly half filled with glacial or waterworn flints, used for fine grinding of certain ores, preliminary to further treatment. The material to be ground, mixed with water, is fed through a trunnion at one end and passes out the opposite trunnion as a slime. This is an exceptionally long mill with a relatively small diameter. Syn: cylindrical mill tubercle texture In mineral deposits, a texture in which gangue is replaced by automorphic minerals. CF: atoll texture 3399

tuberose A mineral exhibiting very irregular rounded surfaces, often giving rise to gnarled, rootlike shapes. Nelson tub hooker The person who hooks or unhooks the hoisting rope to or from the buckets. Hess tubing a. The tube lining of boreholes; casing. Fay b. Hollow cast-iron segments placed in a shaft to dam water or sink through quicksand. Also spelled tubbing. Fay c. See: ventilation tubing d. A small-diameter removable pipe, suspended and immobilized in a well inside a large-diameter casing and opening at a producing zone, through which fluids are produced (brought to the surface). AGI e. The act or process of placing tubing in a well. AGI f. The act of lining a deep borehole by driving down iron tubes. See also: casing g. A misnomer for casing. Long h. Small-diameter removable pipe through which oil and gas are produced from the well. Wheeler, R.R. tubular screw conveyor See: screw conveyor tucanite See: scarbroite tucking frame A frame in timbering in which the poling boards are supported by walings at their upper and lower ends. Hammond tucking space The space between the blocks separating the cap in a heading set from the poling driven. This space provides for driving a second set of poling boards. Stauffer tue irons Blacksmith's tongs. Standard, 2 tufa

3400

A chemical sedimentary rock composed of calcium carbonate, formed by evaporation as a surficial, spongy, porous, semifriable incrustation around the mouth of a hot or cold spring or seep, or along a stream carrying calcium carbonate in solution, and exceptionally as a thick, bulbous, concretionary or compact deposit in a lake or along its shore. It may also be precipitated by algae or bacteria. The hard, dense variety is travertine. The term is rarely applied to a similar deposit consisting of silica. It is not to be confused with tuff. Etymol: Italian tufo. CF: sinter petrified moss. AGI tufaceous Pertaining to or like tufa. Not to be confused with tuffaceous. AGI tuff A general term for all consolidated pyroclastic rocks. Not to be confused with tufa. Adj: tuffaceous. CF: crystal tuff tuffaceous Said of sediments containing up to 50% tuff. CF: tufaceous tuff breccia A pyroclastic rock consisting of more or less equal amounts of ash, lapilli, and larger fragments. AGI tuffite A tuff containing both pyroclastic and detrital material, but predominantly pyroclasts. AGI tuff lava Applied to consolidated, lavalike tuff consisting primarily of lenses of black and gray obsidian lying in a tuffaceous matrix that displays a streaky, varicolored banding or eutaxitic structure. Rocks of this sort are generally considered to be the product of ash flows or nue#1.es ardentes. Syn: welded tuff tuft Eng. Any porous or soft stone, such as the sandstone in the Alston district of Cumberland; tufa. AGI tuft stone 3401

a. Eng. Tufa near Newport, Monmouthshire, and Dursley, Gloucestershire. b. Eng. Toadstone, Derbyshire. See also: toadstone tugger See: air hoist tugger hoist An air hoist for mines. von Bernewitz tugger man See: tugger operator tugger operator In mining, a person who operates a small portable or semiportable hoist (tugger), powered by compressed air or electricity, to raise coal, ore, rock, or supplies in a shaft or stope or along an incline inside a mine. Also called tugger man. DOT tugtupite A tetragonal mineral, Na4 AlBeSi4 O12 Cl ; in the Ilimaussaq massif, southwest Greenland. Formerly called beryllosodalite. tuiles The working openings at the discharging end of a glass furnace. Mersereau, 2 Tukon hardness test A method of determining the hardness of microconstituents by using the Knoop or Vicker's type of diamond indenter. See also: microhardness; Vickers hardness test. Henderson tumble To smooth, clean, or polish, as castings, by friction with each other or with a polishing material in a rotating box or barrel; to rattle. Standard, 2 tumbled

3402

Semiprecious and precious stones, cleaved carbon, or other diamonds, the sharp edges and corners of which have been rounded and blunted by tumbling action in a barrelshaped vessel. Long tumbler a. A projecting piece on a revolving shaft or rockshaft for actuating another piece. In dredges, both an upper and a lower tumbler support the bucket line. Fay b. Any piece of equipment that polishes gemstones by a tumbling action. tumbler test Test for determining relative friability of a particular size of sized coal. Bennett tumbling An operation in which the work, usually castings or forgings, is rotated in a barrel with metal slugs or abrasives to remove sand, scale, or fins. It may be done dry or with an aqueous solution. Sometimes called rumbling or rattling. ASM, 1 tumbling barrel A revolving barrel, cask, or box in which objects or materials (such as small metal parts, castings, plastics, leather, or clothing) undergo a process (such as finishing, polishing, coating, softening, or drying) by being whirled about and so brought into vigorous frictional contact. Also called rattler; rumble; scouring barrel. Webster 3rd tumbling box A tumbling barrel for small objects. Webster 3rd tumbling mill Any horizontally mounted cylindrical mill in which contents are tumbled when rotating. Name often used in connection with cleaning of objects. Pryor, 3 tumbling shaft The camshaft used in stamp mills. Fay tumbling stone N. of Eng. Boulders or detached masses of rock. tumescence 3403

The swelling of a volcanic edifice due to accumulation of magma in the reservoir. It may or may not be followed by an eruption. Syn: inflation AGI tundra A treeless, level or gently undulating plain characteristic of arctic and subarctic regions. It usually has a marshy surface, which supports a growth of mosses, lichens, and numerous low shrubs and is underlain by a dark, mucky soil and permafrost. AGI tundra placer See: gravel plain placer tunellite A monoclinic mineral, SrB6 O9 (OH)2 .3H2 O ; subvitreous to pearly; colorless; forms compact fine-grained secondary nodules; also prismatic and tabular crystals; at Kramer and in the Furnace Creek area of Death Valley, CA. tune work Labor paid for by the day or the hour, in contrast to piecework. Fay tungstate A mineral containing the radical (WO4 )2- , in which the hexavalent tungsten ion and its four oxygens form a flattened square rather than a tetrahedron, e.g., the wolframite series, (Fe,Mn)WO4. Tungsten and molybdenite may substitute for each other. tungsten A hard, brittle, white or gray metallic element. Symbol, W. Also known as wolfram. Found combined in certain minerals such as wolframite, (Fe,Mn)WO4 ; scheelite, CaWO4 ; huebnerite, MnWO4 ; and ferberite, FeWO4 . Tungsten and its alloys are used extensively for filaments for electric lamps, electron and television tubes, X-ray targets, and numerous space missile and high-temperature applications. See also: wolframite Handbook of Chemistry and Physics, 3 tungsten alloy An alloy used in drill-bit-crown matrices and in making bit and reaming-shell inserts by powder methods in which the principal constituent is tungsten, generally in the form of carbide. Tungsten carbide powder usually is mixed with a powdered cobalt or other metal to bind it together in a cohesive mass. Long 3404

tungsten carbide A mixture consisting of 85% to 95% tungsten carbide and 5% to 15% cobalt; sp gr, 12 to 16; Mohs hardness, about 9.0; it is not affected by severe high industrial temperatures. Used for machine tools and for abrasives for machining and grinding metals, rocks, molded products, porcelain, and glass. CCD, 2 tungsten carbide bit A drilling bit tipped with tungsten carbide. A 9% cobalt carbide generally gives the best results, and comparisons are usually referred to bits of this standard. Tests with tungsten carbide bits indicate that efficient drilling is possible only up to a hardness of about 55 Shore; beyond this, wear increases rapidly until, at 62 Shore, the cost becomes prohibitive. Several factors affect the cutting life of the bits, including the grade of carbide used, the rake angle of the cutters, the length of cutting edges, and support of cutters. See also: steel bit; coal-cutter pick; Shore hardness test; sintered carbide-tipped pick. Nelson tungsten carbide insert a. A small plate or slug of tungsten carbide alloy mounted in the crown or shank of a bit or in grooves on the outside surface of a reaming shell to provide wear-resistant or rockcutting surfaces or edges. The term is sometimes incorrectly applied to diamond-set plates of tungsten carbide alloy inset as reaming surfaces in reaming shells. Long b. In mining, a slug composed of tungsten carbide alloy shaped and mounted in the bit face so that the slug acts as the cutting edge of the bit. Long c. Hemispherical-ended cylinders of sintered carbide are inserted in place of the usual teeth to give 10 to 15 times the total footage and 2 to 3 times the cutting rate. However, hard rocks are drilled more economically by diamond boring. Nelson tungsten direct-from-ore process An electrowinning method developed by the U.S. Bureau of Mines for producing highquality tungsten powder directly from ore. A strong electric current separates the metal from the ore, which has been placed in solution, and deposits it as a pure powder on an electrode. Electrowon tungsten compares favorably with hydrogen-reduced tungsten. tungstenite A trigonal or hexagonal mineral, WS2 ; forms dark, lead-gray, minute, foliated or earthy scales; at the Emma Mine, Utah. tungstic ocher See: ferritungstite; tungstite. Also called wolfram ocher. 3405

tungstite An orthorhombic mineral, WO2 (OH)2 ; yellow to green; in oxidized zone of tungsten deposits. Syn: tungstic ocher; wolframine. tunna A Welsh term for a hoisting bucket; a bowk; a kibble. Fay tunnel a. A horizontal or inclined stone drivage for development or to connect mine workings, seams, or shafts. It may be open to the surface at one end and used for drainage, ventilation, or haulage or as a personnel egress (walking or riding) from the mine workings. See also: tunneling Nelson b. See: crut c. A leaden tube used in making sulfuric acid to connect adjoining chambers in a series. Standard, 2 d. A long, narrow subterranean passageway. e. A horizontal or nearly horizontal underground passage that is open at both ends. The term is loosely applied in many cases to an adit. An adit, if continued through a hill, would be a tunnel. Any level or drift in a mine open at one end, or which may serve for an adit. Often used as a syn. for adit; drift; gallery. See also: adit f. To penetrate with or as if with a tunnel; to make a passage through or under; to make or use a tunnel; to undermine. Webster 3rd tunnel blast a. A blast effected by the detonation of great quantities of explosive, loaded in small tunnels driven into the face at the level of the quarry floor or at the level of the terrain at the foot of the slope of the deposit. This blasting method is called tunneling. Streefkerk b. See: heading blast tunnel blasting A method of heavy blasting in which a heading is driven into the rock and afterwards filled with explosives in large quantities. This is similar to a borehole on a large scale, except that the heading is usually divided into two parts on the same level at right angles to the first heading. This forms a T, the ends of which are filled with explosives and the intermediate parts of which are filled with inert material like an ordinary borehole. Similar to gopher hole blasting. See also: gopher hole blasting tunnel borer Any boring machine for making a tunnel; often a ram armed with cutting faces operated by compressed air. Standard, 2 tunnel carriage 3406

A rapid tunneling procedure, consisting of a combined drill carriage and manifold for water and air so that immediately when the carriage is at the face, drilling may commence with no lost time for connecting up, waiting for drill steels, etc. The air is supplied at pressures of 95 to 100 psi (655 to 690 kPa). Nelson tunnel claim When a lode or vein is discovered in a tunnel, the tunnel owner is called upon to locate the area containing the vein or lode on the surface and thus create a mining claim. Ricketts tunnel column A heavy bar used for mounting machine drills in large drifts or tunnels, and usually holding two machines. Fay tunnel excavation Excavation carried out completely underground and limited in width and height. Carson, 1 tunnel face The working face in an excavation or tunnel or other working place from which driving is carried out. Fraenkel tunneling The operation of excavating, driving, and lining tunnels. Nelson tunnel kiln A long tunnel-shaped furnace through which the charge is generally moved on cars, passing progressively through zones in which the temperature is maintained for preheating, firing, and cooling. ARI tunnel-kiln operator One who controls the operation of a tunnel kiln in which bricks are fired, and a preheating chamber in which bricks are heated prior to firing and after drying. DOT tunnel lining

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a. The timber, brick, concrete, or steel supports erected in a tunnel to maintain dimensions and safe working conditions. See also: steel tunnel support; lining. Nelson b. See: ring; tunnel support. tunnelman In anthracite coal mining, one who drives a tunnel in rock from one coal seam to another or through a fault (the movement of the earth having separated a once continuous seam into two sections). DOT tunnel miner A miner experienced in the use and handling of rock drills and shovel loaders, and in tunnel-blasting methods. Such a miner is wholly employed on tunneling and is usually paid a fixed rate per shift with perhaps a bonus payment for high rates of tunnel advance. Nelson tunnel right A right to enter upon and occupy a specific piece of ground for the purpose of carrying out work in a tunnel and extracting waste rock or earth necessary to complete the tunnel, and making such use after completion as may be necessary to work the mining ground or lode owned by the party running the tunnel. By implication, the grant of such a right carries with it every incident and appurtenant thereto, including the right to dump the waste rock at the mouth of the tunnel on the land owned by the grantor at the time of the conveyance of the tunnel right, such right or easement being necessary for the full and free enjoyment of the tunnel right. Ricketts tunnel set Timbers of sufficient strength to support the roof of the tunnel. They are sometimes set upon sills and usually capped with short crosspieces. Fay tunnel shaft A shaft sunk, such as in a hill, to meet a horizontal tunnel. Also called tunnel pit. Standard, 2 tunnel site a. An area for a tunnel. The locator of a tunnel site is given the right to all veins cut by the tunnel within 3,000 ft (915 m) of its portal, and 1,500 ft (457 m) on the strike of each blind vein cut; this length may be all on one side of the tunnel or divided as desired. The veins must be blind lodes not previously known to exist. Lewis b. There is no distinction 3408

between a tunnel claim under which a tunnel is run for the development of veins or lodes already located, and one where a tunnel is projected for blind veins or lodes. Ricketts tunnel support See: steel tunnel support; tunnel lining. tunnel system A method of mining in which tunnels or drifts are extended at regular intervals from the floor of the pit into the orebody. The extension of the drift beyond the working face is made great enough to facilitate the handling of several cars at a time. The ore is mined above the drift level, and the cars are loaded by lifting short boards that span an opening, through the lagging on and above the centerline of the drift. The method avoids the construction of raises and chutes and facilitates the filling of the cars. Fay tup The ram or monkey, or falling weight, of a piledriver, drophammer, etc.; specif., the heavy head of a steam hammer in which the upper pallet is secured. Webster 2nd turanite An orthorhombic(?) mineral, Cu5 (VO4 )2 (OH)4 (?) ; weakly radioactive; green; forms reniform crusts and spherical concretions having a radial fibrous structure with other vanadium and uranium minerals; in cavities in limestone; at Tyuya Muyun, Fergana, Turkistan. turbid Stirred up or disturbed, such as by sediment; not clear or translucent, being opaque with suspended matter, such as of a sediment-laden stream flowing into a lake; cloudy or muddy in physical appearance, such as of a feldspar containing minute inclusions. AGI turbidimeter An instrument for measuring or comparing the turbidity of liquids in terms of the reduction in intensity of a light beam passing through the medium. See also: transmissometer turbidimetry Measurement of the amount of suspended or slow-settling matter in a liquid; the measurement of the decrease in intensity of a light beam passed through a medium. CF: nephelometry 3409

turbidite A sediment or rock deposited from, or inferred to have been deposited from, a turbidity current. It is characterized by graded bedding, moderate sorting, and well-developed primary structures. AGI turbidity a. The state, condition, or quality of opaqueness or reduced clarity of a fluid, due to the presence of suspended matter. AGI b. A measure of the ability of suspended material to disturb or diminish the penetration of light through a fluid. AGI turbidity current A density current in water, air, or other fluid, caused by different amounts of matter in suspension, such as a dry-snow avalanche or a descending cloud of volcanic dust; specif. a bottom-flowing current laden with suspended sediment, moving swiftly (under the influence of gravity) down a subaqueous slope and spreading horizontally on the floor of the body of water, having been set and/or maintained in motion by locally churned- or stirred-up sediment that gives the water a density greater than that of the surrounding or overlying clear water. Such currents are known to occur in lakes, and are believed to have produced the submarine canyons notching the continental slope. They appear to originate in various ways, such as by storm waves, tsunamis, earthquake-induced sliding, tectonic movement, oversupply of sediment, and heavily charged rivers in spate with densities exceeding that of sea-water. The term is applied to a current due to turbidity, not to one showing that property. Syn: suspension current turbidity size analysis A kind of particle-size analysis based upon the amount of material in turbid suspension, the turbidity decreasing as the particles settle. AGI turbine pump A pump with a shrouded impeller and receiving the water at its center. A diffusion ring containing vanes surrounds the impeller and directs the impeller discharge into a circular casing, which delivers into the eye of the next impeller in series. The diffusion ring converts the high-velocity discharge of the impeller into pressure head. The turbine pump is widely used in mines. See also: diffuser chamber turboaxial fan An axial flow fan with a turbine rotor-type impeller. BS, 8 turbocompressor 3410

The type of machine commonly installed at a colliery today where a large volume of compressed air is required. A single unit can deliver 10,000 ft 3 /min (283 m3 /min) or more of free air, and the floor space occupied is a minimum for these capacities. It is also ideally suited for direct drive by a steam turbine, and this combination is commonly found at collieries. The compressor consists essentially of a number of impellers keyed to a shaft and running in a fixed casing with specially shaped passages. Each impeller is in the form of a hollow wheel, the two sides being united by curved vanes. See also: airconditioning process turbodrill In rotary drilling, a drill bit that is directly rotated by a turbine attached to the drill pipe at the bottom of the hole and driven by drilling mud pumped under high pressure. It was developed in the former U.S.S.R. for drilling deep oil wells. AGI turbodrilling A system of drilling in which the bit is directly driven by a turbine at the bottom of the hole. BS, 9 turbulence See: turbulent flow turbulent flow a. Water flow in which the flow lines are confused and heterogeneously mixed. It is typical of flow in surface-water bodies. CF: laminar flow Syn: tortuous flow; turbulence. AGI b. Fluid motion in which random motions of parts of the fluid are superimposed upon a simple pattern of flow. All or nearly all fluid flow displays some degree of turbulence. Opposite of streamline flow. Hunt c. A fluid flow in which there is an unsteady motion of the particles, the motion at a fixed point being inconstant. Turbulent flow occurs at a speed above the critical velocity of Reynolds. Also called tortuous flow; sinuous flow; eddy flow. Nelson d. When air flows over roughnesses on the sides of the airway or passes obstructions at over a certain velocity, eddies are set up in the air and its flow becomes turbulent. Opposite of laminar flow. Spalding e. When the fluid particles are moving in directions other than in a straight line parallel to the axis of the pipe or duct. Strock, 2 turbulent resistance Resistance that causes vortices and eddies to form behind a moving particle because of the rapid displacement of the liquid when the body moves through it. CF: viscous resistance 3411

turf a. Same as peat. There are several varieties, as white, brown, black, stone, gas, or candle turf. Fay b. Sod, the upper strata of topsoil filled with the roots of grass and other small plants. turgite An iron ore and sandstone cement consisting of hematite with adsorbed water. It is fibrous and red in mass with an orange tint where powdered. Also spelled turjite. Syn: hydrohematite Turkey slate A whetstone or honestone. See also: Turkey stone Turkey stone A very fine-grained siliceous rock, containing up to 25% calcite, quarried in central Turkey and used as a whetstone; novaculite. Syn: Turkey slate turkis A turquoise. Standard, 2 turmeric paper Paper impregnated with an extract of turmeric. Used as a test for alkaline substances, which turn it from yellow to reddish-brown, and for boric acid, which turns it red-brown. Webster 3rd turn a. A curve into a pillar. BCI b. The time or period during which coal, etc., is raised from a mine. Also called run; shift. c. To open rooms, headings, or chutes off from an entry or gangway. d. The number of cars allowed each miner. Good turn means many cars for each miner. Fay e. To draw or wind coal up a shaft or up an inclined plane to the surface. Fay f. Curved tramrails, often made of cast iron, laid round a corner or turn. Fay g. To set undried bricks on edge to facilitate drying. Standard, 2 turn angles To measure the angle between directions with a surveying instrument. Nichols, 1 turn bat 3412

A wooden stick used in turning the tongs that hold a bloom under the hammer. Fay turn bolt A bolt turned in a lathe to a close tolerance and used in steel-to-steel connections. Hammond turned vertical shaft A shaft sunk vertically in the hanging wall block until it intersects a reef, after which it is sunk down at an angle in the footwall parallel to the reef. This unusual practice is sometimes adopted on the Rand because it enables the mine to become productive at an earlier stage. See also: incline shaft turnerite A yellowish-brown variety of monazite. Standard, 2 turnhouse a. A point where workings turn from a crosscut to a level along the lode. Gordon b. The first cutting on a lode after it is cut in a crosscut. Syn: house turning effect See: moment of force turning over and packing shift On mechanized longwall faces, the shift during which face conveyors are moved over, and the operations of ripping, packing, and drawing supports from the wastes are performed. Mason turning point a. A surveying point on which a level rod is held, after a foresight has been made on it, and before the differential-leveling instrument is moved to another station so that a backsight may be made on it to determine the height of instrument after the resetting; a point of intersection between survey lines, such as the intervening point between two bench marks upon which rod readings are taken. It is established for the purpose of allowing the leveling instrument to be moved forward (alternately leapfrogging with the rod) along the line of survey without a break in the series of measured differences of elevation. Abbrev: TP. AGI b. A physical object representing a turning point, such as a steel pin or stake driven into the ground. AGI 3413

turning vane Curved strips placed in a sharp bend or elbow in rectangular duct to direct the air around the bend in a streamlined flow. Strock, 2 turn keeper See: motor boss turnout a. The branching off of one rail track from another. Nelson b. A contrivance for passing from one track to another. Zern c. A siding or bypass in an underground haulageway. d. A switch on a mine railroad. Korson turnover a. The distance the conveyor is advanced during each cycle of operations; i.e., approx. the depth of machine cut. See also: conventional machine mining b. A device used to rotate an object through approx. 180 degrees so that its carrying surface is changed to the opposite side. c. See: move-up turn pulley A sheave fixed at the inside end of an endless or tail-rope hauling plane, around which the rope returns. See also: tail sheave turns A term used with any device used to change the direction of a shaker conveyor trough line; e.g., curved trough turn, adjustable angle turn, right angle turn, etc. The angle turn corresponds to the bell crank drive in principle of operation. Jones, 1 turnsheet See: flat sheet turquoise a. A triclinic mineral, 1[CuAl6 (OH)8 (PO4 )4 .4H2 O] with Fe replacing Al toward chalcosiderite; forms waxy blue-green reniform masses having a botryoidal surface, rarely with minute crystals; occurs in arid regions where surface water acted on aluminous rock; may be a gemstone. Also spelled turquois. Syn: Turkey stone; calaite. b. The mineral group aheylite, chalcosiderite, coeruleolactite, faustite, planerite, and turquoise. 3414

turret coal cutter A coal cutter in which the horizontal jib can be adjusted vertically to cut at different levels in the seam, for example, an overcut. The center of gravity of such a machine makes it top heavy and less stable than the ordinary undercutter. See also: overcutting machine; universal coal cutter. Nelson turret jib A vertical rotating jib fitted with cutter picks and driven from the end sprocket of the bottom jib of a coal cutter. The turret jib is satisfactory in seams where the coal parts readily from the roof and is not too hard. See also: mushroom jib; curved jib. Nelson turtle back A name for chlorastrolite (pumpellyite), esp. the green variety with patches of color; also, turquoise matrix or variscite matrix. turtle stone See: septarium turtlestones Large, nodular concretions found in certain clays and marls. In form, they have a rough resemblance to turtles, and this appearance is increased by their being divided into angular compartments by cracks filled with spar, reminding one of the plates on the shell of a turtle. Fay Tuscarora quartzite An important source of raw material for silica refractories. A typical analysis is 97.8% SiO2 , 0.9% Al2 O3 , 0.7% Fe2 O3 , and 0.4% alkalies. Dodd tusiite A former name for calciocopiapite. tutenag a. A white alloy, resembling German silver, used in making tableware, etc., with varying proportions of copper, zinc, nickel, and sometimes a little lead or iron. Standard, 2 b. Zinc or spelter, esp. that from China and the East Indies. Standard, 2 Tutogen 3415

A foam-producing agent used in fire extinguishers. Sinclair, 1 tutwork Sometimes used for piecework or contract work. Nelson tuxtlite A pyroxene mineral, (Na,Al,Ca,Mg)Si2 O6 ; midway in composition between diopside and jadeite; pea-green; massive; at Tuxtla, Mexico. Formerly called diopside-jadeite. Also spelled tuxlite. tuyere A tube or opening in a metallurgical furnace through which air is blown as part of the extraction or refining process. In a blast furnace, the tuyeres are water-cooled metal tubes which pass through the refractory lining of the bosh (tube). Dodd tuyere arch An arch in a blast furnace to admit a tuyere. See also: tuyere Standard, 2; Fay tuyere brick A refractory shape containing one or more holes through which air and other gases are introduced into a furnace. ARI tweel A counterweighted furnace door, opening vertically. Also spelled tuille. ASTM twig a. See: divining rod b. Thin strip of plastic fire clay used in ceramic modeling, esp. in imitation basketwork. Standard, 2 twill cloth Weave used in screens and filters, in which two or more warp threads interweave one wood thread. Pryor, 3 twin axis

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The crystal axis about which one individual of a twin crystal may be rotated (usually 180 degrees ) to bring it into coincidence with the other individual. It cannot be coincident with the axes of twofold, fourfold, or sixfold symmetry. Syn: twinning axis twin colors See: dichroic colors twin-core shot-firing cable See: shot-firing cable twin crystal A composite of two or more crystal individuals having a definite crystallographic relationship to each other. The orientation of one individual may be the mirror image of the other across a twin plane, or an orientation that can be derived by rotating the twin portions about a twin axis, or some other rational twin law. Twinned individuals in a twin crystal commonly show reentrant angles between crystal faces or on cleavage planes. A twin crystal may exhibit symmetry higher than that of its crystal individuals. twin crystals Crystals in which one or more parts, regularly arranged, are in reverse position with reference to the other part or parts. They often appear externally to consist of two or more crystals symmetrically united, and sometimes have the form of a cross or star. They also exhibit the composition in the reversed arrangement of part of the faces, in the striae of the surface, and in re-entering angles; in certain cases, the compound structure can only be surely detected by an examination in polarized light. Fay twin entry A pair of parallel entries, one of which is an intake air course and the other a return air course. Rooms can be worked from both entries. Often called double entry. Fay twin laminae The laminae or thin plates in repeated or polysynthetic twins. CF: polysynthetic twinning; repeated twinning. twin law A statement or statements of the symmetrical relationships between the members of a twin crystal, e.g., the twin plane or the twin axis that resolves one crystal individual into congruity with another in a twin crystal. The twin law cannot be an element of symmetry 3417

of the point group of the twin parts, although it may be an element in a point group with higher symmetry in the same crystal system. twinning axis See: twin axis twinning law The special and characteristic method according to which twin crystals of any mineral are formed. Fay twinning plane In a twin crystal, a plane normal to the twinning axis. Fay twinoriascope A type of instrument used to detect and mark twinning and determine the sense of orientation in etched sections. Am. Mineral., 2 twinoscope An instrument employing a directed beam of light used to examine etched wafers for twinning. Am. Mineral., 2 twin packer A packer designed so that a borehole can be sealed simultaneously at two separated points. Long twin plane In a twin crystal, a plane through which one twin individual forms a mirror image of the other, or the plane at right angles to the axis about which one individual is rotated with respect to the other. The twin plane is commonly the composition plane across which the individuals are joined. With rare exceptions, a twin plane is a possible crystal face for the crystal individuals. twist conveyor An L-shaped conveyor in which the carrying surface and guard gradually exchange their functional duties. twist drill 3418

A drill made by twisting a length of steel of rectangular or oval section into a spiral form, hence the term twist drill. Many hand-operated coal drills are of this type, and the rotation of the drill spiral removes the cuttings from the hole. See also: auger; coal auger. Nelson twisted-loop splice Splice made by holding the bared wires side by side. Half of their length is bent back to form a loop at the end. The loop is then twisted around the main shank of wire. Carson, 1 twister operator In the asbestos products industry, one who twists together two or more strands of wire and asbestos yarn for use in weaving asbestos products, such as brake linings. DOT twisting force A force, such as the force on the shaft of a rotating motor. Morris twistoff The breaking off of a member of the drill string, caused by excessive torsional stress. Long two-circle goniometer A device permitting rotation of a small crystal about two orthogonal axes for optical observation. CF: goniometer two-component explosives Consist of two or more unmixed, commercially manufactured, prepackaged chemicals, including oxidizing chemicals, flammable liquids, or solids that are not independently classified as explosives. When combined, however, the mixture is classified as an explosive and is stored, transported, and handled as an explosive. Cote two-cone bit See: roller rock bit two-fan auxiliary ventilation An arrangement, using two auxiliary fans, for ventilating a mine tunnel or hard heading. It consists of an exhausting fan with rigid ducting to within about 100 ft (30 m) of the 3419

face, and a forcing fan using a flexible duct discharging air about 20 ft (6 m) from the face. The ducts of the two units overlap by at least 30 ft (9 m) to minimize the recirculation of air. The air delivered by the forcing fan does not exceed about one-third of that removed by the exhaust fan. See also: overlap auxiliary ventilation; auxiliary ventilation; recirculation of air; reversible auxiliary ventilation. Nelson twofold A symmetry axis requiring two repetitions to complete 360 degrees and return to identity. Syn: diad two-high mill Contains two horizontal rolls, one above the other. In some two-high mills the direction of rolling can be reversed, and these are known as reversing mills; i.e., when a piece has passed through the rolls, the rolls are stopped and then rotated in the opposite direction, thus imposing another pass on the steel, the operation being repeated until the desired reduction is attained. Between passes, adjustment is made to the height of the top roll, and/or the piece is moved sideways by means of manipulators, to be in line with other grooves in the rolls. Osborne two-hinged arch A rigid frame hinged at both supports. It may have an arched or rectangular form. Hammond two intakes The provision of two intake airways, generally side by side, to a ventilating area of a mine. Nelson two-jaw chuck A chuck equipped with two movable clamping or holding devices by means of which the motion of the chuck is imparted to the drill rods. Long two-leg sling A sling having two chains or ropes which hang from a thimble. See also: single sling two-liquid differential manometer Consists of two concentric glass tubes, each expanded into a large bulb at the upper end. The lower end of the outer tube is sealed, and the inner tube reaches nearly to the bottom of the outer tube. Two liquids are used, and the movement of the interface between the 3420

two liquids down the central tube is used as an index against which the change in pressure is measured. See also: manometer two-mica granite A granite containing both dark mica (biotite) and light mica (muscovite). This rock was called true granite by Rosenbusch and binary granite by Keyes. CF: aplogranite two-part line A single strand of rope or cable doubled back around a sheave so that two parts of it pull a load together. Nichols, 2 two-piece set A set of timbers consisting of a cap and a single post. If the ground is loose and must be supported over the side or back, lagging, commonly of 2-in (5.1-cm) boards, is used. These boards extend from the center line of the post or cap to the middle of the next post or cap. If they are placed touching each other, such an arrangement is called tight lagging; if a few inches apart (which depends on the nature of the ground to be held back), it is called open lagging. See also: timber set two-plane idler A troughing idler in which the troughing roll shafts are in a vertical plane separate from but parallel to a vertical plane through the shaft of the center roll or rolls. NEMA, 1 two-process washer A method of cleaning raw coal in which the material from 8 to 1/16 in (203 to 1.6 mm) in size is treated in heavy-medium washers, and the fines below 1/16 in are treated by froth flotation. Nelson two-speed differential A differential having a high-flow gearshift between the drive shaft and the ring gear. Nichols, 1 two-stage compression Air compression carried out in two stages as is usual for pressures exceeding 60 psi (414 kPa) or for outputs greater than 100 hp (74.6 kW). See also: intercooler two-stage hoisting 3421

Deep-shaft hoisting with two winders, one at the surface and the other at middepth in the shaft. The surface engine winds minerals from the middepth pocket, and the other winds from the pit bottom to the middepth point. The arrangement is often adopted in turned vertical shafts. See also: tandem hoisting two-step control system In flotation, a system in which the manipulated variable alternates between two predetermined values. Fuerstenau two-stroke cycle A working cycle of a piston in an internal combustion engine consisting of two strokes, in which the piston during the first stroke compresses the fuel mixture on one side while receiving the expansive thrust of previously compressed gases on the other side, and during the second draws in a fresh charge on one side while expelling burnt gases on the other. Webster 3rd two-way ram A hydraulic cylinder in which fluid can be supplied to either end, so the piston can be moved by power in two directions. Syn: double-acting ram Nichols, 2 tychite An isometric mineral, Na6 Mg2 (CO3 )4 (SO4 ) , having iron replacing magnesium toward ferrotychite; isomorphous with northupite, Na6 Mg2 (CO3 )4 Cl2 , with which it occurs; forms small white octahedra; at Borax Lake, San Bernadino County, CA. tying across and behind Systematic exploration by a mine rescue team of all intersecting and adjacent passageways so that the team is never forward (toward the working face) of an accessible, unexplored area. MSHA, 4 Tyler sieve See: sieve Tyler Standard series The series of carefully woven, square-mesh wire screens most commonly used in the United States in screening ores. Newton, 1 tymp 3422

Eng. A horizontal roof timber in a coal mine; a cap or lid. Standard, 2 tymp stone A large clay plug filling an open space in the front jackets of a smelting furnace, through which the taphole passes. Standard, 2 tyndallascope See: tyndallometer Tyndall effect The scattering or reflection of a strong beam of light by suspended colloids; no such scattering or reflection comes from true solutions. tyndallometer An instrument that measures the intensity of the light scattered at an angle from the incident beam by a dust cloud. It correlates well with the concentration determined by a thermal precipitator and surface area calculated from such a count. It needs to be calibrated for each type of dust against the thermal precipitator. Syn: tyndalloscope See also: dust sampling tyndalloscope See: tyndallometer type a. See: rock type b. A coal classification based on the constituent plant materials. CF: rank; grade. AGI c. Those differences in coals that are due to variations in the kind of plant material of which the coal is composed, whereby such varieties as common banded coal, cannel coal, algal coal, and splint coal are produced. AGI d. A kind, particularly in petrology (rock type); either general (for example, basalt is a rock type) or particular (for example, a particular basalt from a particular locality is a unique type specified by a description). Challinor type-D drift indicator A single-shot borehole-surveying instrument utilizing photographic paper on which is recorded the compass bearing and inclination of the course of a borehole. The type-D instrument, when mounted in a special thin-walled protective container, is small enough to be used in an AX-size hole. Long 3423

type-M drift indicator A single-shot borehole-surveying instrument that records the compass bearing and inclination of the course of a borehole through the action of a strong beam of light directed through the plumb bob onto a light-sensitive paper disk. It is similar to, but larger than, a type-D drift indicator. Long type of coal a. The concept type provides a means for classifying standard varieties of coal microscopically on the basis of simple proportions of anthraxylon or anthraxylon and opaque attritus, including their subdivision into banded and non-banded coals. IHCP b. A type of coal is a variety initially determined by the nature of the ingredient matter, the conditions of deposition, and the extent of operation of the first or biochemical process of coal making. IHCP type section The originally described sequence of strata that constitute a stratigraphic unit. It serves as an objective standard with which spatially separated parts of the unit may be compared, and it is preferably in an area where the unit shows maximum thickness and is completely exposed (or at least shows top and bottom). AGI type specimen A specimen or individual designated as type of a species or lesser group and serving as the final criterion of the characteristics of that group. Webster 3rd type-W drift indicator A mechanical single-shot borehole-surveying instrument for use where exceptionally high temperatures are encountered in a hole. It records the compass bearing and inclination of a borehole by making a dot on a special paper by means of a plumb bob, incorporating a depressible stylus. Long typhonic rocks Rocks that have come from the depths of the Earth; i.e., plutonic and eruptive rocks. Fay typomorphic mineral A mineral that is typically developed in only a narrow range of temperature and pressure. CF: index mineral typrite 3424

a. A variety of fergusonite found near Arendal, Norway. Fay b. See: sipylite tyre valve Adjustable annular ring, made of plastic, used to control the aperture area at the apex of a hydrocyclone. Pryor, 3 tyrolite An orthorhombic mineral, Ca2 Cu9 (AsO4 )4 (OH)10 .10H2 O ; forms green crystal aggregates having foliated micaceous structure. Formerly called trichalcite. tyuyamunite An orthorhombic mineral, Ca(UO2 )2 (VO4 )2 .8H2 O ; soft; waxy; yellow; fluoresces yellow-green; in secondary encrustations in limestones, sandstones, or concentrated by organic matter; associated with malachite, ferghanite, turanite, barite, calcite, carnotite, and vanadium minerals; widely distributed in the Colorado Plateau area; source of uranium and vanadium. Formerly called calciocarnotite.

U U-bit A popular type of rotary bit used in British mining practice. It has two cutting legs, although some American and German bits employ three legs. A core is formed between the legs, which is broken off as cutting proceeds; some bits have a core-cutting device consisting of a tungsten carbide tip in the center. Fraenkel Udden grade scale A logarithmic grade scale devised by Johan A. Udden (1859-1932), U.S. geologist; it uses 1 mm as the reference point and progresses by the fixed ratio of 1:2 in the direction of decreasing size and of 2:1 in the direction of increasing size, such as 0.25, 0.5, 1, 2, 4. See also: Wentworth grade scale ugrandite The group of calcium garnets uvarovite, grossular, andradite, goldmanite, hibschite, kimzeyite, and schorlomite uhligite 3425

An isometric mineral, (Ca,Ti,Al,Zr)2 O3 ; forms black octahedra in a nepheline syenite near Lake Magad, Tanzania. uigite A discredited term equal to thomsonite. Am. Mineral., 1 uintaite A variety of natural asphalt occurring in the Uinta Valley, Utah, as rounded masses of brilliant black solid hydrocarbon. Syn: gilsonite; mineral rubber. CMD ulexite A triclinic mineral, NaCaB5 O6 (OH)6 .5H2 O ; soft; forms silky white, saline crusts and masses of extremely fine acicular crystals; in saline lake deposits as in Nevada and Chile. Also called cotton ball; boronatrocalcite; natronborocalcite; natroborocalcite. ullmannite A triclinic mineral, NiSbS ; cobaltite group; pseudocubic; metallic; steel-gray to silverwhite; in veins; a source of nickel. Also called nickel-antimony glance. Ullrich magnetic separators These machines have powerful electromagnets in a wedge section. The material is treated on rolls on which magnetism is induced; they consist of alternate disks of soft iron and some nonmagnetic material. The ore is fed over the first roll, which removes the most magnetic material, and the tailings go on to the second, which is weaker, where a second separation is made. Liddell ulmain A kind of euvitrain that consists completely of ulmin but that is not precipitated from solution. CF: collain ulmification The process of peat formation. Tomkeieff ulmin brown See: Vandyke brown ulminite 3426

a. A maceral of brown coal within the huminite group, consisting of gelified plant-cell walls (ICCP, 1971). AGI b. A variety of euvitrinite characteristic of ulmain and consisting of gelified but not precipitated plant material. CF: collinite ulrichite A hypabyssal rock composed essentially of large phenocrysts of alkalic feldspar, sodic pyroxene, amphibole, and nepheline with smaller phenocrysts of accessory olivine. Feldspar, pyroxene, and amphibole recur in the groundmass. A porphyritic variety of olivine-bearing phonolite. Syn: uraninite ultimate analysis a. The determination of the elements contained in a compound, as distinguished from proximate analysis, which is the determination of the compounds contained in a mixture. Standard, 2 b. In the case of coal and coke, the determination of carbon and hydrogen in the material, as found in the gaseous products of its complete combustion, the determinations of sulfur, nitrogen, and ash in the material as a whole, and the calculation of oxygen by difference. ASTM c. The principal reason for the ultimate analysis of coal is for the classification of coals according to rank, although it is often used for commercial and industrial purposes when it is most desirable to know the sulfur content of coal. Also known as total analysis of coal. Cooper ultimate bearing capacity The average load per unit of area required to produce failure by rupture of a supporting soil mass. See also: bearing capacity ultimate bearing pressure The pressure under which a foundation will settle with no increase of load. See also: plate bearing test ultimate CO2 The percent of carbon dioxide that would appear in the flue gases if combustion were perfect. Varies with the fuel. Strock, 2 ultimate compressive strength That point at which failure by crushing occurs. Pryor, 3 ultimate elongation

3427

The percentage of permanent deformation remaining after tensile rupture, measured over an arbitrary length including the section of rupture. Roark ultimately controlled variable In mineral processing, the variable whose control is the end purpose of the automatic control system. Fuerstenau ultimate strength The ultimate strength of a material in tension, compression, or shear, respectively, is the maximum tensile, compressive, or shear stress that the material can sustain, calculated on the basis of the ultimate load and the original or unstrained dimensions. It is implied that the condition of stress represents uniaxial tension, uniaxial compression, or pure shear, as the case may be. Roark ultimate tensile stress The load at which a test piece breaks, divided by its original area. See also: tensile strength ultrabasic Said of an igneous rock having a silica content lower than that of a basic rock. Percentage limitations are arbitrary; the upper limit was originally set at 44%. The term is frequently used interchangeably with ultramafic. Although most ultrabasic rocks are also ultramafic, there are some exceptions; e.g., monomineralic rocks composed of pyroxenes are ultramafic but are not ultrabasic because of their high silica content. A monomineralic rock composed of anorthite would be considered ultrabasic (SiO2 = 43.2%) but not ultramafic. Ultrabasic is one subdivision of a widely used system for classifying igneous rocks on the basis of silica content; the other subdivisions are acidic, basic, and intermediate. CF: ultramafic; silicic. AGI ultrabasite A germanium-bearing variety of diaphorite from Freiberg, Saxony, Germany. ultraflotation A recently developed process for use in fine-particle flotation. The underlying principle is the use of a finely ground (minus 325-mesh) auxiliary mineral as a carrier for the fine particles to be floated. The fine particles form a slime coating on the carrier mineral; the carrier mineral is then floated, and the fines are piggybacked into the froth. Fuerstenau ultramafic 3428

Said of an igneous rock composed chiefly of mafic minerals, e.g., monomineralic rocks composed of hypersthene, augite, or olivine. CF: hypermelanic; ultrabasic. AGI ultramafites Collective name for igneous rocks containing 90% or more mafic minerals; includes picrites, peridotites, and pyroxenites. ultramarine A name for synthetic lazurite; extended to related compounds. Also applied to the durable brilliant blue pigment made from its powder. Syn: lapis lazuli ultramarine yellow A lemon-yellow pigment consisting of barium chromate. Fay ultrametamorphism Metamorphic processes at the extreme upper range of temperatures and pressures, at which partial to complete fusion of the affected rocks takes place and magma is produced. The term was originated by Holmquist in 1909. AGI ultramicroscope A microscope in which a strong beam of light (Tyndall beam) is viewed at right angles. Individual soluble particles too small to be seen under a normal microscope then appear as bright spots against a dark background. Ultramicroscopy operates below 0.25 mu m. Pryor, 3 ultramylonite An ultracrushed variety of mylonite, in which primary structures and porphyroclasts have been obliterated so that the rock becomes homogeneous and dense, with little if any parallel structure. CF: protomylonite; pseudotachylyte. Syn: flinty crush rock ultrasima The supposedly ultrabasic layer of the Earth below the sima, immediately below the Mohorovicic discontinuity. AGI ultrasonic drilling A vibration drilling technique that can be used in drilling, cutting, and shaping of hard materials. In this method, ultrasonic vibrations are generated by the compression and 3429

extension of a core of electrostrictive or magnetostrictive material in a rapidly alternating electric or magnetic field. The most easily assembled is a magnetostrictive transducer, and the most common magnetostrictive materials, which change in dimension when magnetized, are nickel and vanadium permandur. Min. Miner. Eng., 1 ultrasonic inspection A nondestructive method of testing, based upon the fact that ultrasonic waves are reflected and refracted at the boundaries of a solid medium, from which it is possible to obtain the echoes of a wave transmitted from the surface of a test piece. In addition to being reflected from the boundary of the specimen at which they are directed, the waves are also reflected back by any flaws that lie in the path of the wave. Syn: ultrasonic testing ultrasonic testing See: ultrasonic inspection ultrasonic tests Tests in which high-frequency vibrations (inaudible to a human ear) are used to assist in determining wall thicknesses, pulp densities, etc. Pryor, 3 ultrasonography A modification of the use of ultrasonic waves for the detection of internal flaws in metals. By using a persistent screen cathode ray tube and causing the echoes to brighten the trace instead of deflecting it, an ultrasonic image is produced that can be examined and interpreted like a radiograph. Osborne ultraviolet a. Of radiation, beyond the visible spectrum at its violet end; having a wavelength shorter than those of visible light and longer than those of X-rays. Webster 3rd b. Relating to, producing, or employing ultraviolet radiation. CF: visible light ultraviolet rays Electromagnetic waves in the wavelength between visible light rays and X-rays. Ultraviolet light furnishes a quick method of finding and identifying certain metals. Nelson ultrawet Alkylated monosodium benzene sulfonate, a wetting agent. Pryor, 3 3430

ulvite See: ulvoespinel ulvoespinel An isometric mineral, 8[Fe2 TiO4 ] ; spinel group; in mafic igneous rocks as fine exsolution lamellae in magnetite. Named for the Ulvoe Islands, Sweden. Syn: ulvite umangite A tetragonal mineral, Cu3 Se2 ; dark red, tarnishing to violet. umbauhobel A plow developed from the Anbauhobel machine to allow the conversion of a Lobbe Hobel to give the plow an independent drive. Nelson umber A brown earth that is darker than ocher and sienna, consisting of iron oxide and oxyhydroxide with manganese oxides, clay, and lime. Highly valued as a permanent pigment, it may be used in its greenish brown natural state (raw umber) or in the dark or reddish brown calcined state (burnt umber). CF: ocher; sienna. umbrella Protective hood over a hoisting cage in a mine shaft. Pryor, 3 umohoite A monoclinic and orthorhombic mineral, UO2 MoO4 .4H2 O ; black to blue-black; secondary; the only known uranium mineral to contain molybdenum. umpire An assay made by a third party to settle a difference found in the results of assays made by the purchaser and the seller of ore. See also: control assay U.M. plate Universal mill plate, or plate that is rolled to width by vertical rolls as well as being rolled to thickness by horizontal rolls. Osborne unakite 3431

An epidote-rich granite, which also contains pink orthoclase, quartz, also minor opaque oxides, apatite, and zircon. The name is derived from the type locality, the Unaka Range, Great Smoky Mountains, in eastern Tennessee. AGI unbalanced cutter chain A cutter chain that carries more picks along the bottom line than the topline. Most chains for cutting at floor level are unbalanced to assist in keeping the jib down. See also: balanced cutter chain unbalanced hoisting The method of hoisting in small one-compartment shafts where only one cage is in operation, as opposed to balanced winding. Nelson unbalanced shothole A shothole in which the explosive charge breaks down the coal at the back of the machine cut while leaving the front portion standing or in large blocks. This may happen with a deep bottom cut in a thin seam where the vertical distance from the explosive to the inner end of the cut is shorter than the horizontal distance to the exposed face of the seam. Nelson unchuck To disengage the drill chuck from the drill stem. Long unclassified excavation Excavation paid for at a fixed price per yard, regardless of whether it is earth or rock. Nichols, 1 unconfined compression appliance A portable appliance for carrying out uniaxial compression tests at a site. Syn: unrestrained compression apparatus unconfined compression test A special condition of a triaxial compression test in which no confining pressure is applied. See also: triaxial compression test; crushing test. AGI unconfined compressive strength See: compressive strength 3432

unconformability The quality, state, or condition of being unconformable, such as the relationship of unconformable strata; unconformity. See also: unconformity unconformable Said of strata or stratification exhibiting the relation of unconformity to the older underlying rocks; not succeeding the underlying rocks in immediate order of age or not fitting together with them as parts of a continuous whole. In the strict sense, the term is applied to younger strata that do not conform in position or that do not have the same dip and strike as those of the immediately underlying rocks. Also, said of the contact between unconformable rocks. CF: conformable AGI unconformity a. A substantial break or gap in the geologic record where a rock unit is overlain by another that is not next in stratigraphic succession, such as an interruption in the continuity of a depositional sequence of sedimentary rocks or a break between eroded igneous rocks and younger sedimentary strata. It results from a change that caused deposition to cease for a considerable span of time, and it normally implies uplift and erosion with loss of the previously formed record. AGI b. The structural relationship between rock strata in contact, characterized by a lack of continuity in deposition, and corresponding to a period of nondeposition, weathering, or esp. erosion prior to the deposition of the younger beds, and often marked by absence of parallelism between the strata; strictly, the relationship where the younger overlying stratum does not conform to the dip and strike of the older underlying rocks, as shown specif. by an angular unconformity. Syn: unconformability; transgression. AGI unconsolidated strata Rocks consisting of loosely coherent or uncemented particles, whether occurring at the surface or at depth. unconsolidated surface deposits Surface deposits such as moss, peat, sand, gravel, silt, or mud. BS, 7 unconventional mineral deposit A mineral deposit of such unusual grade, mineralogy, or geologic setting that experienced mining personnel would not consider it to be similar to any known deposit type. Barton unctuous 3433

Greasy or soapy to the touch, as certain magnesian minerals. Standard, 2 uncut a. A diamond the original shape of which has not been altered artificially. Long b. Unadulterated. undation theory A theory proposed by Van Bemmelen (1933) that explains the structural and tectonic features of the Earth's crust by vertical upward and downward movements caused by waves that are generated by deep-seated magma. AGI under See: undermanager underboom sprays Sprays located on the rear corners of the shovel at the sides of the continuous miner and aimed towards the front of the gathering arms to suppress dust by wetting the coal. SME, 1 underbreak Rock that remains unbroken inside the neat lines in a tunnel or shaft after firing a round of explosive shots. CF: overbreak underbreaking See: underhand stoping underburden Insufficient burden of rock in relation to the explosive charge, resulting in a blown-out shot or a premature shot through shock of a neighboring charge of a blast pattern, often yielding less work than expected. undercast a. An air crossing in which one airway is deflected to pass under the other. BS, 8 b. The lower airway of an air crossing. See also: air crossing BS, 8 c. An undercast is nothing more than an inverted overcast. Undercasts are not considered to be as efficient as overcasts, owing to the tendency of water to collect in them. CF: overcast 3434

underchain haulage Haulage in which the chains are placed beneath a mine car at certain intervals with suitable hooks that thrust against the car axle. Stoces underchaining A drive is underchained when it incorporates a chain of substantially lower rating than that indicated by normal selection procedures. Jackson, 1 underclay a. A layer of fine-grained detrital material, usually clay, lying immediately beneath a coalbed or forming the floor of a coal seam. It represents the old soil in which the plants (from which the coal was formed) were rooted, and it commonly contains fossil roots (esp. of the genus Stigmaria). It is often a fireclay, and some underclays are commercial sources of fireclay. Syn: underearth; seat earth; seat clay; root clay; thill; warrant; coal clay; warrant clay. AGI b. A bed of clay, in some cases highly siliceous, in many others highly aluminous, occurring immediately beneath a coal seam, and representing the soil in which the trees of the Carboniferous swamp forests were rooted. Stigmarian roots commonly occur as fossils in underclays, many of which are used as fireclays. See also: fireclay underclay limestone A thin, dense, nodular, relatively unfossiliferous fresh-water limestone underlying coal deposits, so named because it is closely related to underclay. AGI undercliff S. Wales. An argillaceous shale forming the floor of many coal seams. underconsolidated soil deposit A deposit that is not fully consolidated under the existing overburden pressure. Not yet in equilibrium with existing physical environment. Still being compacted. ASCE undercurrent A short sluice much wider than the main sluice and set on a steeper grade, generally at right angles to the main sluice. It is designed to save fine gold that does not readily settle. See also: table undercut 3435

a. To remove a horizontal section of kerf in the bottom of a block of coal to facilitate its fall. See also: underhole; undercutting. BCI b. To undermine, to hole, or to mine. To cut below or in the lower part of a coalbed by chipping away the coal with a pick or mining machine. Undercutting is usually done on the level of the floor of the mine. See also: cut; undermine. Fay c. A machine cut along floor level in a coal seam to ease its removal by hand, machine, or shotfiring. See also: holding d. Excavation of ore from beneath a larger block of ore to induce settling under its own weight. Nelson e. In stoping, removal either of footwall or of the lower part of a a flattish lode, bed, or seam of ore or coal, thus facilitating detachment of the portion left hanging. Method used in block caving to induce caving in. Pryor, 3 f. To enlarge a drillhole at a depth that has been previously drilled. undercut atomizer A device for passing a fine spray of compressed air and water to dilute the combustible gases and allay the coal dust in the track of a coal-cutter jib. The spray is passed through a modified whale-type jib. Nelson undercut ignition The ignition of an explosive mixture of combustible gases and air in the undercut of a coal cutter due to frictional sparking. Combustible gases in dangerous quantities often exist in a machine undercut. See also: whale-type jib undercut quarry A quarry in which the walls slant outward (overhang the working face) so as to make the floorspace wider with increasing depth. Fay undercutter a. In salt mining, an electrically driven machine somewhat like a gigantic chain saw. It has a long, thin horizontal bar, about which revolves an endless chain with cutting bits. The most common type is an adaptation of the shortwall coal cutter, a drag-type machine with continuous pick-filled chains to cut at the floor or bottom of the seam. It can make a rapid, continuous cut across the entire width of the face. Kaufmann b. See: machineman undercutting a. The process of cutting under the face of a coal seam with a machine so the coal can be shot down readily. b. A quarrying method intermediate between open pit and adit. Channel cuts, or separations made by wire saws or other means along the quarry walls, are slanted outward; thus, the floorspace is enlarged gradually. Wings or buttresses of stone may be left at intervals for wall support. c. The making of a cut, by hand or coal 3436

cutter, along the floor level in a coal seam to ease its working by hand or breaking by explosive. See also: undercut; floor cut; holing. Nelson undercutting machine An electrically driven machine used to make a cut about 10 ft (3.0 m) deep near the bottom of a coalbed. Hudson undercutting of old workings A method of mining a vein that has been worked out above and in which the shaft is further sunk, with a crosscut being made to the vein at a depth below the previous workings. Stoces underdrilling Drilling below the theoretical blasting bottom. Syn: subdrilling underearth A hard fireclay forming the floor of a coal seam. See: underclay AGI underedge stone The material that forms the floor of an ironstone mine. Nelson underfeed To advance a diamond or other type of rock-drilling bit into rock at a lesser rate than that warranted by the condition of the rock and/or the condition of the bit. Long underfeed stoker A mechanical stoker suitable for small boilers, such as the vertical, water-tube, and locomotive types. Coal is conveyed direct from a bunker or hopper by a feed worm, which forces the fuel up through the bottom of the retort in which it is burned. Volatiles driven off must pass through the ignited fuel, thus eliminating smoke. An underfeed stoker operates most successfully on graded coals with an upper size limit of 1 to 2 in (2.5 to 5.1 cm). See also: stoker; vibrating grate. Nelson underfire a. In ceramics, to fire (as brick) insufficiently. Webster 3rd b. To fire from beneath. Webster 3rd 3437

underflow The oversize material leaving a classifier. Nelson underground bunker a. Arrangements, such as high-capacity supplementary conveyors, staple pits, hoppers, or standage room for cars, positioned at key points between the faces and pit bottom. The object is to enable costly power-loading machines to operate continuously when there are surface or shaft delays. See also: bunker conveyor; gate road bunker. Nelson b. A large-capacity hopper to absorb peak deliveries and provide an even rate of feed to main transport systems, or winding shaft. See also: bunker underground cable A single or multiple conductor cable sheathed in lead or other waterproof materials, carried in a duct beneath the surface of the ground. Crispin underground coal gasification See: underground gasification underground connections Mines or areas that are connected underground shall be considered as a single mine if the underground connections between previously separate mines or areas subject the workers in the respective mines or areas to a reasonable likelihood of danger from mine fires or the products of fires, explosions or the forces and products of explosions, mine inundations, or personnel accidents. underground dam Seal against water or spread of fire. Pryor, 3 underground exploration a. The driving of advance exploring headings and up-and-down boring to establish the continuity and thickness of coal seams or other mineral deposits. See also: exploratory drilling b. Extensions of a known ore deposit may be probed along its strike or dip in which shafts, drifts, or crosscuts may be driven. A study of the habits of known ore shoots, by mapping, surveying, and sampling, is a desirable preliminary to underground exploration. Nelson underground fires 3438

There are two types of underground fires: (1) those that involve exposed surfaces and are known as open, freely burning fires and (2) those that may be wholly or partly concealed and are invariably caused by spontaneous heating of the coal itself, known as gob fires. Mason underground garage See: locomotive garage underground gasification A method of burning the coal in place to produce a combustible gas that can be burned to generate power or processed into chemicals and fuels. Air and/or steam is blown underground to support the controlled combustion in the coal seam. The resultant gaseous mixture is a low-heating-value fuel gas. See also: blind borehole process Syn: underground coal gasification underground geology Usually implies direct evidence derived from shafts, wells, and borings, or obtained by geophysical methods. Also called subsurface geology. Challinor underground glory-hole method A method used in large deposits with a very strong roof. In this method, a deposit is divided by levels and on every level chutes are raised to the next one. Mining starts from the mouth of the chutes in such a way as to develop a funnel-shaped excavation (mill, glory) with slopes so steep that the broken ore falls into the chutes and thus to the cars on the lower level. A sufficiently strong pillar is left for protection at the higher level. Syn: underground milling underground haulage The transportation of coal or minerals from the working face to the shaft bottom. Haulage usually implies trams, tubs, or mine cars drawn by horses, locomotives, electric or compressed-air haulage engines. Conveyors are not generally regarded as a haulage method. See also: gravity haulage; haulage; locomotive haulage; main transport; subsidiary transport. Nelson underground milling See: underhand stoping; underground glory-hole method. underground mine conveyor 3439

Sectional conveyor, usually of the troughed belt type, capable of being lengthened or shortened as mining operations advance or retreat, as contrasted to an above-ground conveyor having a fixed length for reasonably permanent installation. According to location in the mine or usage, underground conveyors may be known as face, room, gathering, main haulage, or intermediate haulage conveyors. See also: belt conveyor; conveyor; haulage conveyor; flight conveyor; mother conveyor. Syn: main conveyor; entry conveyor. underground opening Natural or manmade excavation under the surface of the Earth. Obert underground ore bin See: measuring chute underground shaft A shaft sunk from an adit, tunnel, or working level, through which mining operations are conducted. The upper end terminates underground. A winze or raise becomes an underground shaft when equipped and used for hoisting and the conduct of other mining operations. CF: winze underground station a. An enlargement of an entry, drift, or level at a shaft at which cages stop to receive and discharge cars, workers, and material. Fay b. An underground station is any location where stationary electric equipment is installed for the utilization of electricity. This includes pump rooms, compressor rooms, hoist rooms, battery-charging rooms, etc. c. Excavation housing special equipment. Pryor, 3 underground surveying Distinctive features of underground surveying are that stations are usually in the roof instead of the floor; the object to be sighted and the crosshairs of the telescope must be illuminated; distances are usually measured on the slope; either the transit tripod has adjustable legs or a trivet is used; and often an auxiliary telescope is attached to the transit, either at one end of the horizontal axis or above the main telescope, with the line of sight of the auxiliary telescope parallel to that of the main telescope. Horizontal and vertical distances are computed from slope distances and vertical angles. The transit is set up at one station, being centered by plumb, and the vertical distance from the station to the horizontal axis of the transit is measured. A plumb bob is hung at the next station, with a point on the plumbline marked by some form of clamping target. The vertical angle to the point so marked is measured, and the distance from horizontal axis to the target is taped. Urquhart 3440

underground transformer A flameproof, air-filled transformer of a size up to 300 kV.A, which can be used inby near the face in safety-lamp mines. A nitrogen-filled transformer for mining use is the latest trend. Nelson underground transportation The transporting of ore, rock, people, materials, and supplies through shafts and haulageways, including the loading of ore or rock into cars and carrying it to the surface. Jackson, 3 underground water See: ground water; subsurface water. underground workshop An underground room prepared at an accessible spot in an underground mine in which repairs can be made on the mining equipment used underground. underhand longwall Underground mining technique based on underhand stoping and cut-and-fill stoping with a single advancing face. See also: underhand stoping; cut-and-fill stoping. underhand stope A stope made by working downward from a level. underhand stoping The working of a block of ore from an upper to a lower level; mining downward. The method is particularly suitable for narrow, highly inclined deposits. Syn: horizontal-cut underhand; underbreaking; underground milling. CF: overhand stoping See also: underhand longwall underhand vertical slice See: square-set stoping underhand work Picking or drilling downward. Fay 3441

underhole a. To cut away or mine out the lower portion of a coal seam or a part of the underclay so as to win or get the overlying coal. Craigie b. To mine out a portion of the bottom of a seam, by pick or powder, thus leaving the top unsupported and ready to be blown down by shots, broken down by wedges, or mined with a pick or bar. In England, the terms jad, hole, undercut, kirve, and bench are synonymous. See also: undermine; undercut. Fay underlay The extension of a vein or ore deposit beneath the surface; also, the inclination of a vein or ore deposit from the vertical; i.e., hade. Syn: underlie underlay shaft a. A shaft sunk in the footwall and following the dip of a vein. Also called underlier. Fay b. Shaft that slopes at the dip angle of a lode, but is carried below the ore. Also called a footwall shaft. See also: incline shaft Pryor, 3 underlevel A development level or drift, driven from the surface, in ironstone mining. Nelson underlie a. The angle at which stulls or posts are set between walls. The setting angle is slightly steeper than the perpendicular to the vein, and the post thus tightens with the downward settlement of the hanging wall. Nelson b. To lie or be situated under, to occupy a lower position than, or to pass beneath. The term is usually applied to certain rocks over which younger rocks (usually sedimentary or volcanic) are spread out. Ant: overlie. Syn: underlay underloading Insufficient charging of a ball mill for proper grinding of enamel slip. ACSB, 2 underlying Lying under or beneath; fundamental. See also: seat earth Webster 3rd underlying beds The rocks situated under a deposit or other strata. Stoces 3442

undermanager In Great Britain, the underground mining engineer and senior executive official. Everything that has to do with the underground must be subject to his or her control, esp. regarding safety and health of personnel. Also called underlooker. Syn: under undermine To excavate the earth beneath, esp. for the purpose of causing to fall; form a mine under. See also: undercut; underhole. Webster 3rd underpinning a. Building up the wall of a mine shaft to join that above it. Fay b. The act of supporting a superior part of a wall, etc., by introducing a support beneath it. Fay underpoled copper To reduce to metal the cuprous oxide from blister copper produced in a converter, green poles are pushed into the molten material to bring the percentage of dissolved oxygen below 0.5. If this reaction (which results in flat-topped ingots having a smooth fracture) is incomplete, the ingot fractures too readily and has a darker color. This shows it to have been insufficiently reduced, or underpoled. See also: tough pitch Pryor, 3 underream To enlarge or ream a borehole below the casing. See also: underreaming Long underreamer A tool or device having cutters that can be expanded or contracted by mechanical or hydraulic means and used to enlarge or ream a borehole below the casing or drivepipe. Also called expansion bit; expansion reamer. See also: hydraulic underreamer; underreamer bit. Long underreamer bit The assembled device consisting of the lugs or jaws attached to an expanding mechanism used to enlarge or ream a borehole below a string of casing. See also: underreamer underreamer cutter See: underreamer lug 3443

underreamer lug A diamond set or other type of expansible or contractable jaw on an underreamer bit. Syn: underreamer cutter Long underreaming a. The widening out of the foot of a bored hole or of certain types of foundation piers to increase the load-bearing area. Hammond b. See also: underream underreaming bit An expanding bit used to enlarge the diameter of the hole below the casing to allow the casing to be lowered farther down the borehole. BS, 9 underrope haulage An endless rope haulage in which the ropes run under the cars. The cars are attached singly or in short sets by clips. See also: overrope haulage undersaturated a. Said of an igneous rock consisting of unsaturated minerals; e.g., feldspathoids and olivine. AGI b. Said of a rock whose norm contains feldspathoids and olivine, or olivine and hypersthene. CF: unsaturated; saturated; saturated rock. AGI underscreen water Water that is fed into the cells of a washbox below the level of the screen plate. BS, 5 undersea prospecting The driving of exploring headings seaward from landside mine workings combined with up-and-down boring to establish higher or lower seams. Also, a technique developed by the National Coal Board, Great Britain, for exploration drilling from a tower that can be floated out to sea and grounded on the seabed. Nelson undersea workings See: submarine mines undershot wheel

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a. A vertical waterwheel into the circumference of which are set blades that are pushed by water passing underneath. Webster 3rd b. A waterwheel used for low heads, in which the power is obtained almost entirely from the impulse of the water on the vanes. CTD undersize a. Particles in a screen overflow that are smaller than the normal dimensions of the screen apertures. BS, 5 b. The smaller of two classified products. In the case of ore pulp or fine coal, the undersize is the overflow and the oversize is the underflow. See also: classifier c. A drill hole that is not to size because of gage loss on the bit and/or the reaming shell with which it was drilled. Long d. A bit or reaming shell, the diametric dimensions of which are less than specified as standard. Long e. That part of a crushed material that passes through a screen. f. Material in a product of size smaller than the reference size; may be expressed as a percentage of the product. BS, 5 undersize control screen A screen used for the removal of undersize from a product. BS, 5 undersize core Core the outside diameter of which is less than standard. Long underthrust A low-angle reverse fault resulting from the sliding of the footwall beneath a relatively passive hanging wall. CF: overthrust undertow The seaward return flow, near the bottom of a sloping beach, of water that was carried onto the shore by waves. CF: rip current undertub system The endless-rope system generally used on moderate and constant gradients where the floor is good. In this system, the rope runs underneath the tubs or cars in the center of the rails. Curves are negotiated by a series of small vertical pulleys between the rails and are best of large radius. Clips are generally preferred to lashing chains, and the system suits automatic clipping and unclipping. CF: overtub system Sinclair, 5 undervoltage relays

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Like undercurrent relays, undervoltage relays indicate when voltage is not up to the level it should be. Undervoltage values result in the breaker tripping and staying out until the undesirable condition is corrected. Coal Age, 3 underweight a. The weight of that portion of the strata overlying a coal seam at the face, which is supported by the timber or steel props. See also: nether roof; overarching weight; traveling weight. Nelson b. A diamond bit, the crown of which is inset with diamonds so widely spaced that part of the crown is without cutting points and the bit cannot be made to cut. Fay underwinding A rope or cable wound and attached so that it stretches from the bottom of a drum to the load. Nichols, 2 undeveloped land Land remaining in its natural state, not disturbed by mineral exploration or extraction activities. SME, 1 undiscovered resources Resources, the existence of which are only postulated, comprising deposits that are separate from identified resources. Undiscovered resources may be postulated in deposits of such grade and physical location as to render them economic, marginally economic, or subeconomic. To reflect varying degrees of geologic certainty, undiscovered resources may be divided into hypothetical resources and speculative resources. USGS, 2 undisturbed sample A sample that is as undisturbed as humanly possible, as distinct from a sample disturbed by boring tools. Special appliances are used to obtain such samples from boreholes, and the material is preserved in its natural state in airtight containers. Undisturbed samples are required so that the in-place (in situ) properties of the soil may be determined. It is difficult to obtain undisturbed samples of sandy soils without considerable preparation. See also: soil core undulatory extinction In polarized-light microscopy, said of a mineral that fails to go extinct as a unit under crossed polars, but exhibits waves of extinction sweeping across the grain upon rotation of the microscope stage. Syn: wavy extinction 3446

unequal angle A metal angle section with two legs of unequal length. Hammond uneven fracture A general type of mineral breakage that produces rough and irregular surfaces. CF: fracture unfaced quartz A name given to defaced masses of raw quartz used in the oscillator industry. ungemachite A trigonal mineral, K3 Na8 Fe(SO4 )6 (NO3 )2 .6H2 O ; in thick, tabular rhombohedral crystals; at Chuquicamata, Chile. ungotten Unworked rock of any kind. Arkell uniaxial In optical crystallography, those anisotropic crystals having one direction of apparent isotropy, i.e., one optic axis, corresponding to the unique direction of axial symmetry in the hexagonal, trigonal, and tetragonal crystal systems. Uniaxial crystals are positive if their extreme refractive index (extraordinary ray) is less than their axial refractive index (ordinary ray), negative if greater. CF: isotropic; isotropy; anisotropy; biaxial. uniaxial stone One that has crystallized in the tetragonal, trigonal, or hexagonal crystal system and, therefore, has only one direction or axis of single refraction. CF: biaxial stone unicline An obsolete syn. of monocline. CF: anticlinal bend unidimensional consolidation A test in which the volume change in a soil sample is observed when subjected to increasing increments of load. A soil sample, which may be 3 in (7.6 cm) in diameter and 0.8 in (2 cm) thick, is compressed between two porous stones, and the movement under load is noted. Hammond 3447

unidirectional ventilation a. A form of air travel; the air enters at one point, passes through the workings, and goes out at a distant point. Recirculation is impossible where unidirectional ventilation is used; thus the mine is safer than with recirculated air. Lewis b. Ventilation in which air in adjacent openings flows in the same direction and is entirely fresh or exhaust air. Hartman, 2 uniformitarianism The fundamental principle or doctrine that geologic processes and natural laws now operating to modify the Earth's crust have acted in the same regular manner and with essentially the same intensity throughout geologic time, and that past geologic events can be explained by phenomena and forces observable today; the classical concept that the present is the key to the past. The doctrine does not imply that all change is at a uniform rate and does not exclude minor local catastrophes. Syn: principle of uniformity uniformity coefficient An expression of variety in sizes of grains that constitute a granular material. AGI Unifrax A low-density nitroglycerin powder type of equivalent sheathed explosive. McAdam, 2 unilateral transducer A transducer that cannot be actuated at its outputs by waves in such a manner as to supply related waves at its inputs. Hy un-ionized a. State of a substance that has dissolved without dissociating into ions; solute retaining its compounded state. Pryor, 3 b. State of a substance (in solid, gaseous, or liquid state) with atoms that have neither an excess nor a deficiency of electrons, so that they have no net charges. union shop A shop or mine run according to the requirements of a trade union. CF: open shop unique diameter

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A direction in a crystal parallel to the highest symmetry axis; i.e., the c axis in trigonal, tetragonal, and hexagonal systems; the three reference axes in the orthorhombic system; and the b (or c in the first setting) axis in the monoclinic system. unit Smelter contracts make frequent use of the work unit. A unit means 1%. Since a short ton contains 2,000 lb (907.2 kg), a unit is equivalent to 20 lb/t (10.0 kg/t) of ore. Lewis unit cell A parallelepiped unit of atomic dimensions within a crystal structure, containing all the atoms in the chemical unit in definite, fixed positions; and all the symmetry elements of the space lattice from which the whole crystal or crystal structure is built by regular repetitions of this unit in three dimensions. CF: asymmetric unit unit coal a. Applied to prepared coal as for analysis, and being the pure coal substance considered altogether apart from extraneous or adventitious material (moisture and mineral impurities), which may by accident or through natural causes have become associated with the combustible organic substance of the coal. AGI b. The pure or actual coal substance as derived from taking into consideration the corrected ash. The differentiation between the noncoal substance of a sample being analyzed and the coal itself. It is expressed by the formula: Unit coal = 1.00 - (W + 1.08 A + 0.55 S), where W = water, A = ash, and S = sulfur. AGI united veins Where two or more veins unite, the oldest or prior location takes the vein below the point of union, including all the space of intersection. Ricketts unit operation Recognition, study, application, and control of the principles and factors utilized in a distinct and self-contained process (for example, filtration). This avoids the duplication of effort that attends study of filtration of oil, sugar, ore pulp, etc., as though each involved a unique set of principles. Pryor, 3 unit pressures The total pressure divided by the number of area units on which the load is imposed, such as the diamonds in a diamond-bit crown, usually expressed as pounds per square inch, tons per square foot, pounds per diamond, etc. Long 3449

unit process Distinct and self-contained operations that can be studied individually. In mineral processing, unit processes include crushing, grinding, classification, gravity treatment, pulp conditioning, flotation, thickening, leaching, and filtration. Pryor, 3 unit retardation plate See: selenite plate unit strain Unit tensile strain is the elongation per unit length; unit compressive strain is the shortening per unit length; unit shear strain is the change in angle (radians) between two lines originally at right angles to each other. Roark unit stress The stress or load per unit of area, usually taken per square inch of section. For instance, if a bar is 1 in by 2 in (2.5 cm by 5.1 cm) in section, the unit stress of the bar will be 1,000 divided by 2 (sectional area) or 500 psi (3.4475 MPa). Zern unit train A system delivering coal more efficiently in which a string of cars, with distinctive markings, and loaded to "full visible capacity," is operated without service frills or stops along the way for cars to be cut in and out, from the loading place to the point of delivery. unit value The monetary value of a mineral or rock product per ton or other unit of measurement. See also: value unit ventilation A system of ventilation in which each working face is ventilated by a separate air current. BS, 8 unit weight a. Weight per unit of volume. See also: dry unit weight; effective unit weight; maximum unit weight; saturated unit weight; submerged unit weight; unit weight of water; wet unit weight; zero air voids unit weight. b. The density of a material. See also: density 3450

unit weight of water The weight per unit volume of water; normally equal to 62.4 lb/ft3 or 1 g/cm3 . See also: unit weight univalent a. Having a valence of one. Webster 3rd b. Having one valence; e.g., calcium, which has only a valence of two. Webster 2nd universal arc-shearing machine A machine with a rotating jib head so that vertical or shearing cuts can be made in addition to the arc wall cut. An arcwall machine will cut a 12-ft (3.7-m) heading to a depth of 6 ft (1.8 m) in 10 min. Mason universal clamp A clamping device used on a drill column by means of which a horizontal arm can be affixed at any point on the vertical section of a drill column. Long universal coal cutter A coal cutter with a jib capable of cutting at any height or angle. It may be mounted on crawler tracks. See also: universal machine; turret coal cutter. Nelson universal coupling Coupling that joins two driving shafts that rotate about differently slanted axes. Pryor, 3 universal gas mask Designed as an all-purpose mask for protection against a great variety of toxic gases, vapors, and smokes, including carbon monoxide. It is equipped with an indicator that shows at a glance the remaining service time of the canister for carbon monoxide. This mask is particularly effective for mines, fire fighting, and general industrial uses where the contaminants are of relatively low content. Best, 1 universal-joint couplings These couplings are used where shafts intersect at any angle or where pivoted members must be driven. If there is an offset in the two shafts, or if one or both shafts must change location during operation, two of these couplings are used, and one is fitted with a splined joint mating with the connecting intermediate shaft to allow axial movement. Pit and Quarry 3451

universal lay rope See: lang lay rope universal machine A power-driven coal cutter that will not only cut horizontal kerfs, but will also cut vertical kerfs at any angle, and is designed for operation either on track, crawler treads, or rubber tires. Syn: universal coal cutter; arc shear machine. universal motor An electric motor rated at less than 1 hp (746 W) output that operates on either direct or alternating current. Hammond universal pH indicator Mixture of several indicator dyes, each of which changes color through a specific pH range, so that by suitably combining a wide color change and pH, a reading can be obtained. Pryor, 3 universal plant indicator Indicator plant that is restricted exclusively to rocks or soils of a definite mineral content and not found under any other conditions. CF: local indicator plant universal stage A stage of three, four, or five axes of rotation, attached to the rotating stage of a polarized-light microscope, that enables a thin section or mineral grain under study to be turned in a precisely controlled fashion about three mutually orthogonal axes. It is used to determine precisely the optical properties and parameters of minerals or their orientation in a set of external coordinates. Syn: U-stage; Federov stage. CF: goniometer; spindle stage. universal testing machine An instrument so designed that it is capable of exerting a tensile, compressive, or transverse stress on a specimen under test. Further, it can be adapted for the determination of Brinell hardness, ductility, cold bend, and other properties. The machine consists essentially of three systems: loading, weighing, and indicating, the loading being applied either mechanically or hydraulically. Osborne universal train 3452

A roll train having adjustable horizontal and vertical rolls, so as to produce sections of various sizes. Fay unkeying In attacking a rock face, the first effort of the miner is directed toward making a cut that will permit the succeeding shots to exert the greatest force with the minimum charge of explosive. In doing this unkeying, the miner takes advantage of any persistent seam in the rock face. Stauffer unlimited pump A deep-well pump operated from the level of the ground above. Standard, 2 unloader A machine that unloads iron ore from boats and cars, by power, generally electric. Mersereau, 2 unloading conveyor Any of several types of portable conveyors adapted for unloading bulk materials, packages, or objects from conveyances. See also: portable conveyor unloading trough A short section of trough, designed for insertion in a standard shaker trough, which will allow the coal to be unloaded at that point by being diverted to either side by the unloading trough. C-clamps are used to hold the unloading section in place. Jones, 1 unlocking See: liberation unmix Proprietary flotation collector agent based on emulsified tall oil, fuel oil, and watersoluble aryl-alkyl sulfonate used to treat hematite ores. Pryor, 3 unmixing See: exsolution unoriented 3453

a. Said of a rock specimen whose original position in space, when collected, is unknown. b. Said of a rock fabric that shows no ordered spatial arrangement. CF: preferred orientation c. Said of a map or surveying instrument whose internal coordinates are not coincident with corresponding directions in space. Stokes unpatented claim a. Mining claim to which a deed from the U.S. Government has not been received. A claim is subject to annual assessment work, to maintain ownership. Weed, 2 b. A claim that requires $100 of work to be done each year. A claim cannot be patented until $500 has been spent on it. von Bernewitz c. A mining claim for which the holder has no patent. Under the Multiple Surface Use Act of 1955, discoveries of common varieties of sand, stone, gravel, pumice, cinders, and clay cannot be located as mining claims; however, it does not affect the validity of a discovery in these materials based on the presence of other valuable minerals. Lewis unproductive development The drifts, tunnels, and crosscuts driven in stone, preparatory to opening out production faces in a coal seam or orebody. Horizon mining is characterized by a heavy outlay on the initial unproductive development. See also: dead work; in-the-seam mining; productive development. Nelson unproven area An area in which it has not been established by drilling operations whether oil and/or gas may be found in commercial quantities. Williams unreserved mineral A mineral that belongs to the owner of the land on which or in which it is located. The owner of the land is its exclusive owner and can deal with it freely. Examples include limestone, dolomite, barite, fluorite, fireclay, plastic clay, glass sand, marble, and gypsum. Stoces unrestrained compression apparatus See: unconfined compression appliance unripe diamond See: rock crystal unsaturated 3454

a. Applied to minerals that are incapable of crystallizing from rock magmas in the presence of an excess of silica. Such minerals are said to be unsaturated with regard to silica and include feldspathoids, analcime, magnesian olivine, melanite, pyrope, perovskite corundum, calcite, and perhaps spinel. CF: undersaturated; saturated rock. AGI b. Applied to air that contains less water vapor than the maximum or saturation content for the conditions pertaining. Spalding unscreened coal a. Coal for which no size limits are specified. BS, 4 b. Aust. Run-of-mine coal. unsealing The recovery of a sealed-off mine area that had been sealed to extinguish a fire. Two general systems may be employed: (1) recovering the fire area in successive blocks by means of air locks, and (2) reventilation of the fire area after there is conclusive evidence that the fire has been extinguished. See also: sealed area unsoiling The act or process of removing soil, as in opening a quarry. Standard, 2 unsoundness a. A quarry term that refers to all cracks or lines of weakness, other than bedding planes, that may cause rock to break before or during the process of manufacture. Various types of unsoundness are known locally as joints, headers, cutters, hairlines, slicks, seams, slick seams, dry sewns, dries, and cracks. Fay b. The condition of a solid metal that contains blowholes or pinholes due to gases, or cavities resulting from the liquid-to-solid contraction (that is, contraction cavities). See also: gas evolution unstable a. Said of a constituent of a sedimentary rock that does not effectively resist further mineralogic change and that represents a product of rapid erosion and deposition (as in a region of tectonic activity and high relief); e.g., feldspar, pyroxene, hornblende, and various fine-grained rock fragments. AGI b. Said of an immature sedimentary rock (such as graywacke) consisting of unstable particles that are angular to subrounded, poorly to moderately sorted, and composed of feldspar grains or rock fragments. CF: labile AGI c. Said of a radioactive substance. CF: stable unstable isotope See: radioisotope 3455

unstable relict A relict that is unstable under newly imposed conditions of metamorphism, but persists in a perhaps altered but still recognizable form owing to the low velocity of transformation. A preferable term would be metastable relict. CF: stable relict unstratified Not formed or deposited in strata; specif. said of massive rocks or sediments with an absence of layering, such as granite or glacial till. AGI unwatering Pumping or draining the water from mines. CF: dewatering unweathered See: fresh upcast a. The opening in a mine through which the return air ascends and is removed. Ant: downcast; intake. See also: air shaft b. An upward current of air passing through a shaft, or the like. c. Material that has been thrown up, such as by digging. Webster 3rd d. Same as upthrow, such as the upcast side of a fault; opposite of downthrow or downcast. Standard, 2 e. The lifting of a seam or bed by a dike. Syn: uptake upcast shaft a. A shaft through which air leaves the mine. BS, 8 b. The shaft up which the ventilating current of air returns to the surface or to the fan. The term corresponds to main return or return drift in drift mining. Also called fan shaft. Syn: uptake See also: downcast shaft upconing See: coning upgrade a. To increase the commercial value of a coal by appropriate treatment. BS, 5 b. To increase the quality rating of diamonds beyond or above the rating implied by their particular classification. Long c. To increase the quality of grades. upgrading 3456

See: aggradation uphill shaker conveyor Any shaker conveyor that is so designed as to have the proper stroke for shaking the maximum amount of coal up a grade. On certain types of shaker conveyors, this requires the replacement of certain parts of the drive to secure the desired stroke, rather than replacing the entire drive unit. Jones, 1 up hole a. A borehole collared in an underground working place and drilled in a direction pointed above the horizontal plane of the drill-machine swivel head. Long b. A shothole drilled in rock at an upward angle. Pryor, 3 uphole shooting In seismic exploration, the setting off of successive shots in a shothole at varying depths to determine velocities and velocity variation of the materials forming the walls of the hole. AGI uphole time Used to denote the observed travel time of a seismic wave from the point of generation at a given depth in a shothole to a detector at the surface; the observed time equivalent of the corresponding shot depth. Syn: time at shot point uplift a. Any force that tends to raise an engineering structure and its foundation relative to its surroundings. It may be caused by pressure of subjacent ground, surface water, expansive soil under the base of the structure, or lateral forces such as wind. AGI b. A structurally high area in the crust, produced by positive movements that raise or upthrust the rocks, as in a dome or arch. CF: depression AGI up-over Designating a method of shaft excavation by drifting to a point below and then raising. Webster 2nd upper a. Pertaining to rocks or strata that are normally above those of earlier formations of the same subdivision of rocks. The adjective is applied to the name of a chronostratigraphic unit (system, series, stage) to indicate position in the geologic column and corresponds to 3457

late as applied to the name of the equivalent geologic-time unit; e.g., rocks of the Upper Jurassic System were formed during the Late Jurassic Period. The initial letter of the term is capitalized to indicate a formal subdivision (e.g., "Upper Devonian") and is lowercased to indicate an informal subdivision (e.g., "upper Miocene"). The informal term may be used where there is no formal subdivision of a system or series (counterpart of lower). CF: lower; middle. AGI b. See: up hole Upper Barren Coal Measures The part of the Carboniferous strata of the Appalachian field that is now assigned to the Dunkard group of the Permian series. Obsolete. Fay upper break The upper bend of a terrace or monocline. Also called head. upper explosive limit of flammability The highest quantity of combustible gases that, when mixed with a given quantity of air (or oxygen), will just support a self-propagating flame. Francis, 2 Upper Productive Coal Measures The part of the Carboniferous strata of the Appalachian field that is now assigned to the Monongahela group of the Pennsylvanian series. Obsolete. Fay upraise An auxiliary shaft, a mill hole, carried from one level up toward another. See also: rise; raise. (These are better terms.) Fay upright See: post upright fold A fold having an essentially vertical axial surface. Syn: vertical fold AGI upright joints Eng. Vertical joints. See also: thorough joints upset 3458

a. A narrow passage driven on a slope, leaving a wider pillar which is to be mined by slabbing or otherwise. Hess b. A narrow working place driven from one pair of entries to another for the development of a long face in semilongwall or longwall mining. Hess c. A tubular part such as a drill rod, the wall thickness of which has been increased by hot forging for a short distance on one or both ends, thereby reinforcing the area in which screw threads are cut. See also: inside upset; outside upset. Long d. To increase the diameter of a rock drill by blunting the end. Fay upsetting A means of increasing the diameter of a red-hot steel bar during forging by striking it on the end, a state that also occurs in riveting. Hammond uptake See: upcast; upcast shaft. upthrow a. The upthrown side of a fault. AGI b. The amount of upward vertical displacement of a fault. CF: downthrow; heave. AGI upward-current washer A washer in which separation takes place under the influence of an upward current of water or dense medium. BS, 5 uraconite A name used for amorphous, yellow, hydrous uranium sulfates of unknown composition. Syn: uranic ocher uralborite A monoclinic mineral, CaB2 O2 (OH)4 ; dimorphous with vimsite; forms radiating fibrous aggregates; at a skarn deposit in the Turinsk area of the Urals, Russia. Uralian emerald a. Emerald from near Sverdlovsk in the Ural Mountains, Russia. b. A green variety of andradite garnet (demantoid), occurring as nodules in ultramafic rocks in the NizhniyTagilsk district of the Ural Mountains; may be of semiprecious gem quality, although rather soft. Also known as Bobrovska garnet. uralite 3459

A fibrous amphibole pseudomorphous after pyroxene. A trade name for a fireproof material, chiefly of asbestos. uralitization The development of amphibole from pyroxene; specif. a late-magmatic or metamorphic process of replacement whereby uralitic amphibole results from alteration of primary pyroxene. Also, the alteration of an igneous rock in which pyroxene is changed to amphibole; e.g., the alteration of gabbro to greenstone by pressure metamorphism. AGI uramphite An orthorhombic(?) mineral, (NH4 )(UO2 )(PO4 ).3H2 O ; meta-autunite group; forms bottle-green flakes in the oxidation zone of a uranium-coal deposit. uran Combining form meaning containing uranium; e.g., uranothorite. Syn: uranourania ceramics Ceramic products containing appreciable amounts of UO2 (or thorium) that are used in atomic reactors. They are stable against corrosion. uranian opal A variety of opal having an apple-green fluorescence reputedly caused by the presence of minute amounts of uranium. Crosby uranic ocher See: uraconite uraninite An isometric mineral, UO2 , commonly impure with actinide and lanthanide rare earths, radium, helium, and zirconium; strongly radioactive; metamict; generally black; sp gr, 10.9; in pegmatites and veins with lead, tin, and copper minerals; a source of uranium called pitchblende where massive and metamict. See also: pitchblende Syn: ulrichite; coracite. uranite A general term for any mineral consisting of uranyl phosphate and arsenate of the autunite, meta-autunite, and torbernite groups. 3460

uranium A radioactive, silvery-white, metallic element. Symbol, U. Occurs in numerous minerals such as pitchblende, uraninite, carnotite, autunite, uranophane, davidite, and tobernite. It is also found in phosphate rock, lignite, and monazite sands. Uranium and its compounds are highly toxic, both chemically and radiologically. Uranium is of great importance as a nuclear fuel; it is used as ballast for missile reentry vehicles, as a shielding material, and for production of high-energy X-rays. Handbook of Chemistry and Physics, 3 uranium borides Three borides are known: UBr2 , UBr3 , and UBr4 . The most attention has been paid to the tetraboride, the properties of which are: melting point, >2,100 degrees C (but oxidizes rapidly above 600 degrees C); sp gr# = 9.38 g/mL; thermal expansion, 7.1 X 106 (20 to 1,000 degrees C); modulus of rupture (20 degrees C), 60,000 psi (414 MPa); electrical resistivity, 3 X 10-5 ohm.cm. Dodd uranium disintegration series The series of nuclides resulting from the decay of uranium-238. The mass numbers of all members of the series are given by 4n+2, where n is an integer; therefore, the sequence is also known as the 4n+2 series. It is also known as the uranium-radium series. Glasstone uranium galena Galena containing Pb 206, the lead isotope produced by radioactive decay of U 238. uranium-lead See: radium G uranium minerals More than 150 uranium-bearing minerals are known to exist, but only a few are common. The five primary uranium-ore minerals are pitchblende, uraninite, davidite, coffinite, and brannerite. These were formed by deep-seated hot solutions and are most commonly found in veins or pegmatites. The secondary uranium ore minerals, altered from the primary minerals by weathering or other natural processes, are carnotite, tyuyamunite and metatyuyamunite (both very similar to carnotite), torbemite and metatorbernite, autunite and metaautunite, and uranophane. Pearl uranium oxide

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The important oxides of uranium are UO2 , UO3 , and U3 O8 . The dioxide (melting point 2,880 degrees C) is used as a nuclear-fuel element. Uranium oxide has been used to produce red and yellow glazes and ceramic colors. Dodd uranium trioxide Red, orange, and yellow; UO3 ; an intermediate product in the refining of uranium. uranmica See: torbernite; uranite. uranoSee: uran uranocircite A tetragonal mineral, Ba(UO2 )2 (PO4 )2 .10H2 O ; autunite group; yellow-green. uranolite A meteorite. Fay uranophane A monoclinic mineral, Ca(UO2 )2 [(SiO3 )(OH)]2 .5H2 O ; dimorphous with uranophanebeta; radioactive; soft; yellow; as secondary coatings, commonly associated with autunite and torbernite around uranium deposits; a source of uranium. uranopilite A monoclinic mineral, (UO2 )6 (SO4 )(OH)10 .13H2 O ; radioactive; yellow; secondary on uraninite; associated with gypsum and metauranopilite. uranorthorite A variety of thorium silicate; thorite containing a small percentage of oxide of uranium. Fay uranosphaerite A monoclinic mineral, BiUO3 (OH)3 ; radioactive; orange to red; an oxidation product of pitchblende. Also spelled uranospherite. 3462

uranotantalite See: samarskite uranothallite See: liebigite uranothorianite Thorianite with uranium in partial substitution for thorium. Crosby uranothorite A uranian variety of thorite. uranotile See: uranophane uranphyllite See: torbernite uranpyrochlore An isometric mineral, (U,Ca,Ce)2 (Nb,Ta)2 O6 (OH,F) ; pyrochlore group; radioactive; yellow-brown; with samarskite in pegmatites in Mitchell County, NC, and at Hybla, ON, Canada. Formerly called hatchettolite. CF: betafite urao A mixture of trona and thermonatrite. See also: sodium sesquicarbonate urea A tetragonal mineral, CO(NH2 )2 . Carbonyl diamide; also called carbamide. Ure's process The treatment of quicksilver ores by heating in iron retorts with admixture of lime. Fay Urgonian

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A division of the European Lower Cretaceous characteristically developed in certain parts of France and Belgium. Standard, 2 urnel Eng. Kentish term for ragstone. Also spelled urnell or ournal. urolith A pathogenic precipitate occurring in humans and other animals. They are very complex and include numerous biominerals, chiefly phosphates and oxalates. Syn: kidney stone urtite A light-colored member of the ijolite series that is composed chiefly of nepheline and 0% to 30% mafic minerals, esp. acmite and apatite. CF: melteigite (now Lovozero), Kola Peninsula, Russia. AGI Uruguay amethyst a. A deep violet, very transparent amethyst. b. Any amethyst originating along the border between Uruguay and Brazil. usable diamond A resettable salvage diamond. See also: usable stone; usables. Long usable iron ore The product of a mine, or of a beneficiating or agglomerating plant, which is shipped without further processing to the consumer. USBM, 7 usables Salvaged diamonds considered as being fit for resetting and reuse in another bit or tool. See also: usable diamond usable stone See: usable diamond used bit A diamond bit so dulled by use that it is no longer of any value as a cutting tool. Long 3464

useful area Working area of a screen. The nominal area, less any area occupied by fixings or supports that obstruct the passage of material over or through the screen deck. BS, 5 useful pressure For a mine fan, the natural ventilation pressure deducted from the total ventilation pressure required to circulate air through the mine. Roberts, 1 Usspurwies arch An articulated yielding arch, provided by a single bolted joint at the crown. The joint is so designed that the bolt is not subjected to shear stress. The yield element is a rectangular box in which the foot of the arch rests. The resistance to yield is by means of a piece of crushing timber placed in the box from the bottom before setting. See also: steel arch; steel support; Toussaint-Heintzmann arch. Nelson U-stage See: universal stage ustarasite A mineral, Pb(Bi,Sb)6 S10 ; forms gray prismatic crystals in bismuth ore at the Ustarasaisk deposit in western Tyan-shan, Siberia. usual mining privileges By this term in a deed, the grantee has and may enjoy the right to go upon the land and explore for, open, and operate mines, take out and sell the products, and do all things incident to that work. Ricketts utahite A discredited term for jarosite or natrojarosite. See also: natrojarosite utahlite A compact, nodular variscite from Lewiston, Cedar Valley, UT. English U-tube manometer The vertical U-tube is the simplest type of pressure gage and consists either of a single U-shaped glass tube having a uniform bore with vertical arms or two separate glass tubes 3465

connected to a cistern. The level of the liquid in the vertical U-gage can be read easily to 0.1 in (2.5 mm) and in well-made instruments to 0.05 in (1.3 mm) water gage. See also: manometer uvanite An orthorhombic(?) mineral, (UO3 )2 V6 O15 .15H2 O(?) ; radioactive; brownish-yellow; in asphaltic sandstone with carnotite, rauvite, hewettite, metatorbernite, hyalite, and gypsum; from Utah; resembles carnotite. uvarovite An isometric mineral, Ca3 Cr2 Si3 O12 ; garnet group; crystallizes in emerald green dodecahedra and trapezohedra; in serpentinite and in skarns. Also spelled ouvarovite or uwarowit. Syn: chrome garnet; chromium garnet. uvite The trigonal mineral, (Ca,Na)(Mg,Fe)3 Al5 Mg(BO3 )3 Si6 O18 (OH,F)4 , of the tourmaline group. uwarowit See: uvarovite uzbekite See: volborthite

V vacancy A point defect in a crystal structure where an atom or ion is missing from its expected position. Syn: Schottky defect vacant land As defined by its opposite, land is not vacant when occupied as a mining claim without discovery by one who is diligently prospecting it for minerals that it may contain. Ricketts Vacquier-Steenland method 3466

A numerical method used in gravity interpretation for calculating the depth to the source of many typical total field anomalies. The method involves the computation of the curvature of the observed total intensity by superposition of a special grid over the intensity contours. The curvature is proportional to the second vertical derivative of the magnetic intensity. Dobrin vacuole See: vesicle. vacuum A method of producing ventilation by exhausting air from a mine. See also: vacuum fan vacuum casting a. The casting of metals in vacuum. Also called suction casting. See also: vacuum metallurgy b. Slip casting in which the slip is de-aired before casting. vacuum common fine salt VCF; evaporated salt made in vacuum pans; of ordinary purity and ordinary screen analysis. Kaufmann vacuum concrete Concrete poured into a framework that is fitted with a linen filter in the form of a vacuum mat. As a result of the process ensuing, the concrete attains its 28-day strength in 10 days and has a 25% higher crushing strength. Hammond vacuum deposition Condensation of thin metal coatings on the cool surface of work in a vacuum. ASM, 1 vacuum fan A fan for creating suction or partial vacuum. An exhaust fan. See also: vacuum vacuum filter a. A form of filter in which the air beneath the filtering material is exhausted to hasten the process. b. One in which the pulp is drawn into contact with a porous septum by means of a moderately high vacuum. Solids are arrested and filtrate drawn through. In the drum and disc types, filtration is continuous. Vacuum is produced by means of a pump. See also: pulp 3467

vacuum filtration a. The separation of solids from liquids by passing the mixture through a filter and where, on one side, a partial vacuum is created to increase the rate of filtration. It may be used to extract fine coal from the suspension or cyanide solution for reuse. Nelson b. See also: filter vacuum lifting Lifting by a crane fitted with a suction pad, employed for such items as precast concrete components, large panes of glass, and sheet steel. Hammond vacuum metallurgy The processing of metals at elevated temperatures, usually by induction heating in high vacuum. See also: vacuum casting vacuum method In flotation, a method in which the pulp, saturated with air at atmospheric pressure, is allowed to rise to a height above the normal hydrostatic level of the pulp. In the course of this ascent, the dissolved gases precipitate from solution and form a vast number of very tiny bubbles that attach themselves selectively to the hydrophobic solids. Gaudin, 2 vacuum method of testing sand A method of carrying out a triaxial test on a sand sample by maintaining a partial vacuum in the rubber bag containing the sample. Hammond vacuum pump a. A centrifugal or reciprocating pump that extracts steam or air from a chamber or pipe to create a partial vacuum. A vacuum pump, hand or power operated, is part of a pump station equipment where gravity flow is absent. Nelson b. See: pulsometer c. A pump for exhausting air or other gas from an enclosed space to a desired degree of vacuum. Webster 3rd d. A pump in which water is forced up a pipe by the difference of pressure between the atmosphere and a partial vacuum. CF: air pump vacuum system A two-pipe, steam-heating system equipped with vacuum pumps to permit maintenance of pressure below atmospheric within the radiators. Strock, 2 vadose water 3468

Water of the zone of aeration. Syn: suspended water vaesite An isometric mineral, NiS2 ; pyrite group. vake Soft, compact, mixed claylike material with a flat, even fracture, found most often in volcanic terrains. Not recommended. See: wacke valaite A pitch-black resin of unknown composition. Found in thin crusts on dolomite and calcite in the Coal Measures of Moravia, Czechoslovakia. Tomkeieff Valantin conveyor cutter A cutter chain on an armored flexible conveyor that cuts its own stable holes; pushed by pulsating rams; height, 18 in (45.7 cm); minimum workable seam, 20 in (50.8 cm); on gradients 0 degrees to 20 degrees ; maximum length of face, 45 yd (40 m). Nelson valence The degree of combining power of an element or a radical. valence bond Linkage of pairs of electrons so as to unite their atoms as a molecule. When an element has more than one valence, its commonest combination is called the principal valence. Pryor, 3 valence crystals Crystals whose atoms are held in position by covalent bonds; e.g., diamond and silicon. Newton, 1 valencianite A variety of adularia in a silver mine at Valencia, Guanajuato, Mexico. Valentine scale

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Pocket-sized beam scale of Chinese origin used in valuation of alluvial tin gravels. The beam is so calibrated as to read in catties per cubic yard when concentrates from washing of 1/4 ft3 (0.007 m3 ) are weighed. Pryor, 3 valentinite An orthorhombic mineral, Sb2 O3 ; soft; dimorphous with senarmontite; an oxidation product of antimony ores. Syn: white antimony valentite Antimony trioxide, Sb2 O2 , in orthorhombic crystals. Syn: white antimony; antimony trioxide. valleriite A hexagonal mineral, 1.53[(Mg,Al)(OH)2 ].[(Fe,Cu)S] ; an irrational but discrete interlayer complex of hydroxide and sulfide layers; massive; soft; resembles pyrrhotite in color. vallevarite A light-colored monzonitic igneous rock composed chiefly of andesine, microcline, and antiperthite, with small quantities of clinopyroxene, biotite, and apatite. The name, given by Gavelin in 1915, is for Vallevara, Sweden. Obsolete. AGI valley brown ore A local name for comparatively pure high-grade limonite or brown iron ore in CambroOrdovician limestones in the Shenandoah Valley of Virginia. See also: mountain brown ore valley fill A fill structure consisting of any material other than coal waste and organic material that is placed in a valley where side slopes of the existing valley measured at the deepest point are greater than 20 degrees , or the average slope of the profile of the valley from the toe of the fill to the top of the fill is greater than 10 degrees . Vallum diamond Rock crystal (quartz) from the Tanjore District, India. Val separator 3470

A launder used for cleaning buckwheat, rice, and barley sizes of anthracite. It has three distinguishing features: (1) a mixing tank at the head end of the machine, (2) a baffle in the bottom of the machine next to the mixing tank to facilitate the stratification of the solids in specific gravity layers, and (3) the use of a screen and bed of slate in the free discharge boxes. Mitchell valuation a. The act or process of valuing, or of estimating the value or worth; appraisal. Webster 3rd b. The value or estimated price set upon a thing. Webster 3rd value The valuable constituents of an ore; their percentage in an orebody, or assay grade; their quantity in an orebody, or assay value. See also: assay grade; assay value; unit value. AGI valve tower A tower built up within a reservoir to house the control valves of supply pipes drawing off water at different levels. Hammond vamping The debris of a stope, which forms a hard mass under the feet of a miner. Fay van a. To separate, such as ore from veinstone, by washing it on the point of a shovel. Fay b. A shovel used in ore dressing. Fay vanadate A salt or ester of vanadic acid; a compound containing the radical (VO4 )3- (ortho) or (VO3 )- (meta). CF: arsenate; phosphate. vanadic ocher A native yellow vanadium oxide found near Lake Superior. Standard, 2 vanadinite A hexagonal mineral, Pb5 (VO4 )3 Cl ; apatite group; soft; varicolored; sp gr, 6.7 to 7.1; in oxidized zones of lead ore deposits; in New Mexico, Arizona, Africa, Scotland, and Russia. Syn: vanadite 3471

vanadite See: descloizite; vanadinite. vanadium A gray or white, malleable, ductile, metallic element. Symbol, V. Found in about 65 different minerals, among which are carnotite, roscoelite, vanadinite, and patronite; also found in phosphate rock, certain iron ores, and some crude oils. About 80% of the vanadium now produced is used as a ferrovanadium or as a steel additive; also used in ceramics, as a catalyst, and in the production of a superconductive magnet. Handbook of Chemistry and Physics, 3 vanadium minerals Those most exploited for industrial use are patronite (MoS2 with vandium sulfide) , roscoelite (vanadium mica), vanadinite, carnotite, and chlorovanadinite. Metal is silvery and whitish; melting point is 1,720 degrees C; used in high-speed steels and shockresistant alloys, chemicals, ceramics, and textiles. Pryor, 3 vanadium ore Most vanadium is obtained from vanadium-bearing magnetite (1% to 2.2% V) in South Africa. Other sources include patronite, carnotite, roscoelite, vanadinite, descloizite, and volborthite. vanadium-zirconium turquoise See: zirconium-vanadium blue vanalite A monoclinic mineral, NaAl8 V10 O38 .30H2 O ; forms bright-yellow incrustations on weathered shales; in northwest Kara-Tau, Kazakhstan. Van Allen radiation zone Powerful doughnut-shaped zone of radiation 1,000 to 3,000 miles above the Earth's surface and parallel with the Equator. AGI van Arkel and de Boer process See: iodide process vandenbrandeite 3472

A triclinic mineral, Cu(UO2 )(OH)4 ; radioactive; dark green to black; secondary; associated with kasolite, sklodowskite, malachite, goethite, chalcocite, chalcopyrite, uraninite, curite, uranophane, and cobalt wad; occurs at Karungwe, Katanga, Republic of the Congo. Also spelled vandenbrandite. vandenbrandite A very rare, strongly radioactive, triclinic, dark green to almost black mineral, Cu2+ (UO2 )(OH)4 ; a secondary mineral found associated with kasolite, sklodowskite, malachite, geothite, chalcocite, chalcopyrite, and uraninite; also found associated with curite, uranophane and cobalt wad; from Karungwe, Katanga, Zaire. Also spelled vandenbrandeite. Crosby; Hey, 1 vandendriesscheite An orthorhombic mineral, Pb(UO2 )4 (OH)9 .2H2 O ; radioactive; forms small, amberorange pseudohexagonal crystals, commonly barrel shaped; at Katanga, Congo. van der Kolk method A test used in microscopy to determine the index of refraction of a mineral grain relative to that of an immersion liquid. When transmitted light is blocked, the grain acts as a lens and the ocular inverts the image of the obstacle, causing a shadow to appear on the same side as the obstacle when the grain has the higher refractive index, but on the opposite side when the grain has the lower index. Syn: oblique illumination method van der Waals bond Weak forces in crystal structures caused by induced dipoles resulting from juxtaposition of molecules; e.g., the bonding between electrostatically neutral layers in the talc structure. van Dorn sampler This sediment sampler consists of a Plexiglas cylinder closed at each end by an ordinary rubber force cup. The two cups are connected by a length of surgical rubber tubing inside the cylinder, prestressed enough to permit the force cups to retain the sample in the cylinder. In the armed position, the two cups are pulled outside the cylinder, where they are restrained by a releasing mechanism attached to the outside wall. Two short loops of wire connect the cups to the releasing mechanism. The cups are released underwater by sending a messenger down the hydrographic wire. This sampler does not invert, which prevents use of reversing thermometers in conjunction with sampling. Hunt Vandyke brown 3473

a. A naturally occurring pigment derived from indefinite mixtures of iron oxide and organic matter. Obtained from bog earth and peat deposits, or from ochers containing bituminous matter. CCD, 2 b. Etymol: its use by the 17th-Century Flemish painter Van Dyck. Syn: ulmin brown vane The target of a leveling staff; one of the sights of a compass or quadrant. Webster 3rd vane anemometer a. A small windmill-type instrument used to measure air velocity and to infer air volume movement. The vane anemometer has been the primary instrument for airflow measurement since the early 1900's. Hartman, 2 b. See also: anemometer c. Consists of several light, flat vanes, usually eight in number, mounted on radial arms that are attached to a horizontal spindle. This rotor drives, through a suitable gear train, a counting mechanism that indicates the revolutions of the rotor. The indicating dial, usually graduated in feet of air, may be located either concentrically with the rotor, or in a plane at right angles to the plane of rotation. By observing the number of revolutions over a timed interval, the velocity of flow is found. The instrument is available in a number of forms to cover velocities ranging from 30 to 6,000 ft/min (9.1 to 1,830 m/min). Roberts, 1 vane-axial fan An airfoil (propeller) or disk fan within a cylinder and equipped with air-guide vanes either before or after the wheel; includes driving-mechanism supports for belt drive or direct connection. Strock, 2 vane shear test An in-place shear test in which a rod with thin radial vanes at the end is forced into the soil and the resistance to rotation of the rod is determined. ASCE vane shear tester A device used in soil testing, consisting of flat blades affixed to the end of a rod. It is forced into the soil, and the torque required to shear the soil, in situ, is determined as a measure of the shear strength of the zone tested by rotating the device. Syn: vane tester vane test An in-place test to measure the shear strength of fine-grained cohesive soils and other soft deposits. A rod with four flat radial blades, or vanes, projecting at 90 degrees 3474

intervals is forced into the soil and rotated; the torque required to rotate the rod is a measure of the material's shear strength. AGI vane tester See: vane shear tester vanner grease belt In ore dressing, smelting, and refining, used for separation of valuable mineral from the gangue (waste minerals) in an ore. DOT vanoxite A mineral, V6 O13 .8H2 O(?) ; a mixed-valence oxide; weakly radioactive; black; in the Colorado Plateau area as a sandstone cement; also a massive wood replacement associated with carnotite, gypsum, hewettite, pintadoite, tyuyamunite, and pyrite. See also: kentsmithite vanthoffite A monoclinic mineral, Na6 Mg(SO4 )4 ; colorless; at Wilhelmshall, Stassfurt, Germany. vanuralite A monoclinic mineral, Al(UO2 )2 (V2 O8 )(OH).8H2 O ; yellow; at Mounana, Gabon. vapart mill A centrifugal grinder for pulverizing ore, coal, and coke. Fay vapor a. A substance in the gaseous state as distinguished from the liquid or solid state. Webster 3rd; Zimmerman b. Foul air in a mine. CF: gas vapor barrier A material intended to prevent the passage of water vapor through a building wall to prevent condensation within the wall. Strock, 2 vapor density The relative density of a gas or vapor as compared with some specific standard (as hydrogen). Abbrev., v d. Webster 3rd; Zimmerman 3475

vaporization See: evaporation vapor pressure The pressure at which a liquid and its vapors are in equilibrium at a definite temperature. If the vapor pressure reaches the prevailing atmospheric pressure, the liquid boils. Symbol, p. Hackh; Handbook of Chemistry and Physics, 2 vapor system A steam-heating system operating at pressure very near that of the atmosphere. Strock, 2 vara Any of various old Spanish units of length used in Latin America and the Southwestern United States, equal in different localities to between 31 in and 34 in (78.7 cm and 86.4 cm); e.g., a unit equal to 33.3333 in (84.666 cm) in Texas, to 33.372 in (84.764 cm) in California, to 33.00 in (83.82 cm) in Arizona and New Mexico, and to 32.9931 in and 32.9682 in (83.802 cm and 83.739 cm) (among others) in Mexico. For other values, see ASCE (1954). AGI V-arching Rock failure above a tunnel due to ring stresses. These cause rock to crack across a weakness plane and fall. The final shape is a reentrant V rather than a rounded arching. Syn: arching to a weakness See also: arching Varian nuclear magnetometer This magnetometer is available in two models, one for airborne surveys and the other for use on the ground. Both measure the total magnetic field of the Earth rather than its components. Dobrin variation The angle by which the compass needle deviates from the true north; subject to annual, diurnal, and secular changes. Called more properly declination of the needle. See also: declination Standard, 2; Fay variation compass A compass of delicate construction for observing the variation of the magnetic needle. Webster 2nd 3476

variegated Said of a sediment or sedimentary rock, such as red beds or sandstone, showing variations of color in irregular spots, streaks, blotches, stripes, or reticulate patterns. AGI variegated copper ore Bornite, erubescite. Pryor, 3 variegated ore See: bornite varietal mineral A mineral that is either present in considerable amounts in a rock or characteristic of the rock; a mineral that distinguishes one variety of rock from another. Syn: distinctive mineral variety In mineralogy, a mineral showing differences in color, other physical properties, or minor variations in composition from the material considered typical of the species. An example is emerald, the green-colored gem beryl. Hess variogram A plot of the variance (one-half the mean squared difference) of paired sample measurements as a function of the distance (and optionally of the direction) between samples. Typically, all possible sample pairs are examined, and grouped into classes (lags) of approx. equal distance and direction. Variograms provide a means of quantifying the commonly observed relationship that samples close together will tend to have more similar values than samples far apart. variole A pea-size spherule, usually composed of radiating crystals of plagioclase or pyroxene. This term is generally applied only to such spherical bodies in basic igneous rock, e.g., variolite. CF: spherulite variolite A fine-grained igneous rock of basic composition containing varioles. Not recommended usage. AGI 3477

variolitic Said of the texture of a rock, esp. a basic igneous rock, composed of pea-size spherical bodies (varioles) in a finer-grained groundmass. CF: spherulitic variometer A geophysical device for measuring or recording variations in terrestrial magnetism; a variable inductance provided with a scale. AGI variscite a. An orthorhombic mineral, AlPO4 .2H2 O ; dimorphous with metavariscite; waxy; forms nodular masses in cavities where phosphate water acts on aluminous rock. Variscite is a popular gem material for cabochons and various carved objects, commonly substituting for turquoise. Syn: lucinite; utahlite. b. The mineral group mansfieldite, scorodite, strengite, and variscite. CF: amatrice varislope screen A suspended multiple deck screen with increased slopes in the second and third deck. It is used principally for coal and other large feed materials and combines scalping and sizing operations. The oversize lump material is removed on the top deck, egg or range size on the second, and nut size on the bottom deck. See also: trislope screen; vibratory screen. Nelson varlamoffite A mineral that is perhaps a variety of cassiterite. varulite A monoclinic mineral, (Na,Ca)2 (Mn,Fe)3 (PO4 )3 ; alluaudite group; forms dull olivegreen granular masses; at Varutrask, Sweden. varve a. A sedimentary bed or lamina or sequence of laminae deposited in a body of still water within 1 yr's time; specif. a thin pair of graded glaciolacustrine layers seasonally deposited, usually by meltwater streams, in a glacial lake or other body of stillwater in front of a glacier. A glacial varve normally includes a lower summer layer consisting of relatively coarse-grained, light-colored sediment (usually sand or silt) produced by rapid melting of ice in the warmer months, which grades upward into a thinner winter layer, consisting of very fine-grained (clayey), often organic, dark sediment slowly deposited from suspension in quiet water while the streams were ice bound. Counting and 3478

correlation of varves have been used to measure the ages of Pleistocene glacial deposits. AGI b. Any cyclic sedimentary couplet, as in certain shales and evaporites.--Etymol: Swedish. AGI varve clay See: varved clay varved clay A distinctly laminated lacustrine sediment consisting of clay-rich varves; also the upper, fine-grained, winter layer of a glacial varve. Syn: varve clay varves Clayey soil containing thin alternate layers of different particle sizes; often combine the undesirable properties of clay and silt; formed from seasonal deposits from glacial streams. Nelson vashegyite An orthorhombic mineral, Al4 (PO4 )3 (OH)3 .13H2 O(?) ; at Vashegy, Hungary, and near Manhattan, NV. vat a. A vessel or tub in which ore is washed or subjected to chemical treatment, as cyanide vat and chlorination vat. Syn: tank b. Salt pit. AGI c. A term used in the Southwestern United States for a dried and encrusted margin around a waterhole. AGI vaterite A hexagonal mineral, CaCO3 ; trimorphous with calcite and aragonite; at Ballycraigy, Larne, Northern Ireland. vaughanite A pure, dense, homogeneous, dove-colored, fine-textured limestone that breaks with a smooth and more or less pronounced conchoidal fracture that contains relatively few fossils, and that typically has a white, chalky appearance on weathered surfaces. Named after T. Wayland Vaughan (1870-1952), U.S. paleontologist. AGI vauquelinite A monoclinic mineral, Pb2 Cu(CrO4 )(PO4 )(OH) ; fibrous. 3479

vauxite A triclinic mineral, FeAl2 (PO4 )2 (OH)2 .6H2 O ; less hydrous than metavauxite or paravauxite; blue. V-bob A strong frame shaped like an isosceles triangle, turning on a pivot at its apex and used as a bell crank to change the direction of a main pump rod. It is used with Cornish pumping engines. Webster 3rd; Fay V-box Sloughing box, used to separate slime (as overflow) from faster-settling portion of solids in pulp. Pryor, 3 V-bucket conveyor elevator See: gravity-discharge conveyor elevator VCR See: vertical crater retreat V-cut a. In mining and tunneling, a cut where the material blasted out in plan is like the letter V; usually consists of six or eight holes drilled into the face, half of which form an acute angle with the other half. Fay b. In underground blasting, a type of cut employed in which the cut holes meet in a V to pull the cut to the bottom of the holes properly. A single pair of holes may do in one kind of rock, but in another, two or three sets of Vholes entirely across the face may be needed. Also See also: wedge cut veatchite A triclinic and monoclinic mineral, Sr2 B11 O16 (OH)5 .H2 O ; trimorphous with p-veatchite and veatchite-A. vector a. An entity represented as a directed magnitude, such as velocity, which is defined as consisting of a speed and a direction. See also: scalar Hy b. See: hard vector vee cut 3480

See: wedge cut; V-cut. vees a. A layer of soft clay or earth on the sides of a fault or dike. Syn: veez b. The acute angle between the fault plane and a coal seam; e.g., working the coal to the vees of the fault. Nelson vee table A pneumatic table, of U.S. design, for the drycleaning of coal, an improved form of the S.J. table. Nelson veez See: vees vegasite See: plumbojarosite vegetable jelly Same as fundamental jelly, carbohumin, etc. Syn: jelly Tomkeieff veil a. A removable plate to cover a screen, the action of which is not desired. Zern b. An aggregate of minute bubbles creating a whitish or cloudlike appearance in quartz. c. A variously formed weblike or netlike film in a radiolarian; e.g., patagium. vein a. An epigenetic mineral filling of a fault or other fracture in a host rock, in tabular or sheetlike form, often with associated replacement of the host rock; a mineral deposit of this form and origin. CF: lode See also: true vein b. A narrow waterway or channel in rock or earth. Also, a stream of water flowing in such a channel. AGI c. A thin, sheetlike igneous intrusion into a fissure. Not recommended usage. AGI d. A coal seam or a bed of slate or other rock. Not recommended usage. BS, 11 e. A zone or belt of mineralized rock lying within boundaries clearly separating it from neighboring rock. It includes all deposits of mineral matter found through a mineralized zone or belt coming from the same source, impressed with the same forms and appearing to have been created by the same processes. Ricketts f. A mineral deposit, usually steeply inclined. Used to describe a body that is usually smaller and has better defined walls than a lode. Nelson g. A rock fissure filled by intruded mineral matter. Many valuable minerals are codeposited with 3481

gangue stuff in veins. Usually the formation is steep to vertical, unlike a bedded deposit in which values are sandwiched horizontally. Vein is typically long, deep, and relatively narrow. Pryor, 3 h. The term lode is commonly used synonymously for vein. i. The filling of a fissure or fault in a rock, particularly if deposited by aqueous solutions. When metalliferous, it is called by miners a lode; when filled with eruption material, a dike. A bed or shoot of ore parallel with the bedding. Also called blanket deposit. Standard, 2 j. A comparatively thin sheet of igneous rock injected into a crevice in rock. When this intrusion is large, it is called a dike. k. An irregular, sinuous, igneous injection, or a tabular body of rock formed by deposition from solutions rich in water or other volatile substances. Holmes, 2 l. A mineral body, thin in relation to its other dimensions, which cuts across the bedding and in which the minerals are later than the country rock. BS, 11 m. Sometimes used for a bed; e.g., a coal seam or a bed of slate. BS, 11 n. A layer, seam, or narrow irregular body of material different from surrounding formations. See also: vein or lode claim veined gneiss A composite gneiss with irregular layering. The term is generally used in the field and has no genetic implications (Dietrich, 1960). CF: venite; composite gneiss. AGI vein intersection a. The depth in the borehole at which the hanging and/or footwall of a vein is encountered. Long b. The place where two or more veins cross or meet. Long vein material See: veinstuff vein miner A miner experienced in the winning and working of mineral veins. See also: metal mining vein or lode claim The terms "vein or lode" and "vein or lode claim" are used indiscriminately and interchangeably, and it follows that the term "vein or lode" is intended to be synonymous with the term "vein or lode claims." See also: vein; lode; lode claim. Fay vein quartz A rock composed chiefly of sutured quartz crystals of pegmatitic or hydrothermal origin and commonly of variable size. AGI 3482

veinstone The valueless stone that occurs with the valuable minerals in lodes and veins. Also called lodestuff; matrix; vein mineral; veinstuff. Sometimes mistakenly called gangue. Nelson; Fay veinstuff a. All the minerals occurring in a vein. See also: lodestuff b. Gangue. Syn: vein material vein system An assemblage of veins of a particular area, age, or fracture system, usually inclusive of more than one lode. AGI velardenite See: gehlenite velikhovite A variety of pyrobitumen having a shining conchoidal fracture and occurring in the form of veins. It is partly soluble in organic solvent; sp gr, 1.2. In many ways it is similar to grahamite. It is assumed that it represents a weathering product of albertite. From the South Urals, Russia. Tomkeieff velocities in pipes Experience has proved that the following are allowable velocities in pipes: air, 30 to 50 ft/s (9.1 to 15.2 m/s); compressed air, 25 to 40 ft/s (7.6 to 12.2 m/s); steam, 160 to 250 ft/s (46.8 to 76.2 m/s); water, 5 to 10 ft/s (1.5 to 3.0 m/s). Hammond velocity a. In explosives, the speed (in meters or feet per second) at which the detonating wave passes through a column of explosives. A high-velocity explosive renders a shattering effect, whereas a low-velocity explosive has a pushing or heaving effect. Syn: high velocity b. Linear flow rate of air per unit time. Measured in meters per second. Hartman, 1 c. A vector quantity that indicates a time rate of motion. AGI velocity determination The determination of velocities and average velocities within the earth by seismic measurements. AGI 3483

velocity discontinuity An abrupt change in the velocity of propagation of seismic waves within the earth, as at an interface. AGI velocity distribution Relationship between seismic wave velocity and depth. Schieferdecker velocity head a. The constant difference of height of a liquid between a level surface in a tank and a uniformly flowing jet through an orifice. Standard, 2 b. The distance a body must fall under the force of gravity to acquire the velocity it possesses. See also: kinetic energy c. The energy possessed per unit weight of a fluid owing to its velocity. If at a given point the velocity is v feet per second, the velocity head at this point, v2 /2g, g being the acceleration due to gravity in feet per second squared. Also called kinetic head. Syn: velocity pressure velocity lag See: distance lag velocity meter A seismometer used to record the velocity of ground motions. AGI velocity of air current The higher the velocity of the air current, the greater will be the resistance to airflow. The resistance is nearly proportional to the velocity squared. Mason velocity of approach a. The average velocity of water in a channel at the point where the depth over a flow measuring weir is recorded. Hammond b. The mean velocity in the conduit immediately upstream from a weir, dam, Venturi throat, orifice, or other structure. Seelye, 1 velocity of detonation a. The velocity with which the shock wave traverses an explosive charge on detonation. BS, 12 b. The velocity of detonation of an explosive was previously determined by what is known as the Dautriche test. The basis of this test is that a length of Cordtex detonating fuse detonates at a uniform speed, and if the two ends of a length of Cordtex are detonated simultaneously, the detonation waves will meet at the middle of the length 3484

of fuse. Similarly, if the two ends are detonated at different times, the distance from the middle of the fuse to the point where the two detonation waves meet is directly proportional to the interval of time between the detonations of the two ends of the Cordtex fuse. Furthermore, if the distance can be measured, the interval of time between the detonation can be calculated, since the velocity of detonation of Cordtex is known. Syn: Dautriche test velocity of retreat An average velocity of flow of a liquid just downstream of a measuring weir. Hammond velocity pressure a. The pressure equivalent of the air velocity at any particular point. This is always positive. BS, 8 b. The pressure exerted by a moving fluid in the direction of its motion. It is the difference between the total pressure and the static pressure. Strock, 2 c. In Mine ventilation, the pressure exerted by the kinetic energy of air movement. Syn: velocity head d. The algebraic difference between the total head and the static pressure. Roberts, 1 velocity profile A linear arrangement of sensors used to record reflections over a large range of shot-togeophone distances, which is used to determine seismic velocity from the time-distance relationship. AGI velocity ratio The ratio of the distance through which the force applied to a machine moves, and the distance through which the load moves. See also: mechanical advantage velocity reducing collector This type of collector is designed to remove very large dust particles. It is often used ahead of other collectors to reduce the dust load, and to remove the particles most likely to cause abrasion. The velocity reducing collector has no moving parts and, in most instances, can be installed in front of the induced draft fan, reducing the abrasion of the fan blades. This type of collector also can be used under many high-temperature conditions. Pit and Quarry velometer A small portable direct-reading instrument used to measure the velocity of air at a point. Hartman, 2 3485

velvet Profit; easily earned money. Fay velvet copper ore Cyanotrichite in bright blue velvetlike druses and spherical forms. Syn: lettsomite; cyanotrichite. vend Products sold by coal mine annually. Pryor, 3 vendeennite A variety of fossil resin from Vendee, France. Tomkeieff Venetian red A high-grade ferric-oxide pigment of a purer red hue than either light red or Indian red. Obtained either native as a variety of hematite red or more often artificially, by calcining copperas in the presence of lime. The composition ranges from 15% to 40% ferric oxide and from 60% to 80% calcium sulfate. The 40% ferric oxide is the pure grade, and sp gr, 3.45. CCD, 2 venite Migmatite of which the mobile portion(s) were formed by exudation (secretion) from the rock itself (Dietrich & Mehnert, 1961). CF: veined gneiss; composite gneiss. Not widely used. AGI vent a. In explosives, a small passage made with a needle through stemming, for admitting a squib to enable the charge to be lighted. b. A hole, extending up through the bearing at the top of the core-barrel inner tube, that allows water and air in the upper part of the inner tube to escape into the borehole or into the annular space between inner and outer barrels. Long vent bag An enclosed airway to direct airflow to a given area or location. MSHA, 4 ventilating column 3486

See: motive column ventilating current A current of air traveling in mines. Peel ventilating fan See: mine ventilating fan ventilating pressure a. The total head in pascals or kilopascals required to overcome the friction of the air in mines and to provide some final or exit velocity to discharge the air to the atmosphere. b. The total pressure exerted on the atmosphere by the mine fan to overcome the resistance of the mine to the passage of a required volume of air throughout the mine necessary for its ventilation. See also: mine total head; fan total head; total ventilating pressure. Kentucky ventilation Mine workings are usually subdivided to form a number of separate ventilating districts. Each district is given a specified supply of fresh air and is free from contamination by the air of other districts. Accordingly, the main intake air is split into the different districts of the mine. Later, the return air from the districts reunite to restore the single main return air current at or near the upcast shaft. See also: compound ventilation; fan drift; regulator. Nelson ventilation department A department for the purpose of planning adequate and economic ventilation for all future projects and to provide frequent information on existing ventilation systems. Nelson ventilation doors A door constructed to restrict the flow of ventilation air while permitting the passage of personnel and equipment. See also: door; separation door. ventilation ducts Two kinds are available, flexible and rigid ducts. Flexible ducts generally consist of flexible tubes made from fabrics coated with rubber or polyvinyl chloride, a nonflammable substance. They are available in varying lengths. Flexible ducting is suited for face ventilation in a variety of mining methods. It is suited also to crooked 3487

workings of limited extent. It has a higher resistance and a greater tendency to leak than rigid ducting. Rigid ducts are made of steel or fiberglass in lengths suitable for underground transport. This type of duct does not have to be accurately aligned and is therefore used, in the smaller sizes, in subsidiary work, particularly in crooked headings. For main tunnels where leakage must be minimized, flanged joints are used with suitable gaskets. Roberts, 1 ventilation efficiency One measure of the efficiency of a mine ventilation system is the ratio of the total amount of air actually reaching the working faces to the total amount (volume in cubic feet per minute) of air handled by the fan. See also: overall ventilation efficiency; thermometric fan test; ventilation standards; volumetric efficiency. Kentucky ventilation mason A worker who erects by rough masonry or cement work, partitions of stone, brick, or concrete blocks to control proper circulation of air through passageways outby working places. DOT ventilation plan A plan or drawing, required by law, that shows the ventilation air currents in a mine and the means of controlling them. BS, 7 ventilation planning When a new mine is projected or a new seam is to be worked from an existing mine, plans are prepared to show the proposed ventilating system, including the quantities of air and pressures and the principal appliances to control and distribute the air. Investigations and calculations are made to select a fan of the necessary type and size for the ventilation required. All of this important work comes within the general term ventilation planning. See also: air requirements; pressure survey; ventilation survey. Nelson ventilation pressure a. The pressure or head producing ventilation in a mine and measured by the height of a column of water it will support. The instrument used for this purpose is a water gage. b. Pressure producing the flow of air, measured by a water gage, or the difference in level between the two ends of the water column in a vertical U-shaped tube, one end of which is connected to the air under pressure--for example, in the passageway leading to the fan-the other end being to the atmosphere. In some cases, the ventilating pressure is reported as meters of water in the U-tube; in other cases, the head is given in pascals or kilopascals. 3488

ventilation regulator See: regulator ventilation standards The standards prescribed by regulations to provide air underground of a certain degree of purity. See also: ventilation efficiency Nelson ventilation stopping See: stopping ventilation survey a. Systematic observation of air pressure, quantity and quality, throughout a mine or part of a mine, to allow a detailed analysis of the ventilation system. Syn: pressure-quantity survey Sinclair, 1; BS, 8 b. To distribute the air in a mine efficiently and economically, ventilation surveys are conducted. They may be classified as qualitative, quantitative, and pressure surveys. Qualitative surveys determine the proportion of flammable or poisonous gas, or dust, in the air that is being circulated through the mine. In hot and humid mines, they determine the conditions of air temperature and humidity. Quantitative surveys determine the quantity of air being circulated through the mine workings for a variety of reasons. This is done by measuring the volume of air passing at different points in the circuit by means of an anemometer, to investigate the existing air distribution, particularly to the individual faces; the location of leakage; and the possibility of its reduction or elimination. Pressure surveys measure the pressure absorbed and the resistance of the roadways and faces included in the survey. This enables determination of the power required to circulate the air in the different sections of the circuit and that is expended in ventilating individual districts. The total power expended in ventilating the mine may then be summed and the cost estimated. See also: ventilation planning Sinclair, 1; BS, 8 ventilation symbols A set of standard letters, signs, or marks used on mine ventilation plans to represent certain appliances or constructions to direct and control the flow of air underground. Nelson ventilation tubing Sheet steel or canvas piping 12 to 24 in (0.3 to 0.6 m) in diameter for conducting air to or from a tunnel, hard heading face, or sinking pit. The tubing extends from an auxiliary fan to within a few yards of the face to be ventilated. See also: tubing; auxiliary ventilation. Nelson 3489

ventilator a. A mechanical apparatus for producing a current of air underground, as a blowing or exhaust fan. b. A furnace for ventilating a mine by heating the upcast air. c. A device for providing fresh air to a room or other space by introducing outside air or by exhausting foul air. Crispin vent pipe See: vent tube vent tube a. Hose or piping conducting air-ejected drill cuttings from the borehole collar to a point some distance from the drill. Long b. An exhaust pipe or tube. Long c. Tubing suspended from a wire in a mine opening to supply fresh air to a working place. Syn: vent pipe ventubes Tubes of steel, fiberglass, or coated fabric with thin walls that can be easily connected. They are used in mine ventilation to lead air wherever it is needed. Also called ventilation tubing. Stoces Venturi A contraction in a tube or duct to accelerate the flow and lower the static pressure. It is used for metering and other purposes. Venturi blower a. A device resembling a Venturi meter that directs a jet of compressed air for ventilating short headings. The device is commonly made at a mine, and one well-proved type is called the Modder Deep. These blowers are mainly used in conjunction with ventilation ducting for the ventilation of headings several hundred feet in length. Roberts, 1 b. An apparatus to induce a flow of air or gas in a duct by means of a jet of compressed air or water from a small nozzle in the duct. BS, 8 Venturi flume a. A type of open flume with a contracted throat that causes a drop in the hydraulic gradeline; used for measuring flow. Seelye, 1 b. A control flume that comprises a short constricted section followed by one expanding to normal width. See also: control Venturi meter 3490

A trademark for a form of the Venturi tube arranged to measure the flow of a liquid in pipes. Small tubes are attached to the Venturi tube at the throat and at the point where the liquid enters the converging entrance. The difference in pressure heads is shown on some form of manometer and from this difference and a knowledge of the diameters of the tubes, the quantity of flow is determined. Webster 2nd Venturi tube A closed conduit that is gradually contracted to a throat causing a reduction of pressure head by which the velocity through the throat may be determined. The contraction is generally followed, but not necessarily so, by gradual enlargement to original size. Piezometers connected to the pipe above the contracting section and at the throat indicate the drop in the pressure head, which is an index of flow. Seelye, 1 vent wire A wire used by founders to make a hole in a sand mold for the escape of air or gases. Standard, 2 venus hairstone See: rutilated quartz Venus's hairstone Quartz containing needle-shaped crystals of rutile. See also: Thetis hairstone; sagenitic quartz; sagenite. Standard, 2 verde antique A dark-green rock composed essentially of serpentine (hydrous magnesium silicate) usually crisscrossed with white veinlets of marble. Found in California, Georgia, Maryland, Massachusetts, New York, and Virginia. Used as an ornamental stone. In commerce, it is often classed as a marble. CCD, 2; Sanford verdelite A green variety of elbaite (tourmaline). verde salt See: thenardite Verdet's constant 3491

The rotation of the plane of polarization per centimeter per unit magnetic field in the Faraday effect. The value of the constant varies with temperature and is approx. proportional to the square of the wavelength of the light. CTD verdite A deep green, relatively soft metamorphic rock of green fuschite (chromian muscovite) and clay with scattered grains of rutile; occurs in Transvaal and Zimbabwe; is carved for ornamental use. verdolite Talcose-dolomitic breccia rock from New Jersey. Schaller verifier a. A tool used in deep boring for detaching and bringing to the surface portions of the wall of the borehole at any desired depth. Fay b. In gas testing, an apparatus by which the amount of gas required to produce a flame of a given size is measured; a gas verifier. Standard, 2 vermeil a. An orange-red garnet. Syn: vermilion b. A reddish brown to orange-red gem variety of corundum. c. An orange-red spinel. Syn: vermeille vermeille See: vermeil vermicular quartz Quartz in wormlike intergrowths with feldspar. See also: myrmekite vermiculite A monoclinic mineral, (Mg,Fe,Al)6 (Si,Al)8 O20 (OH)4 .8H2 O ; mica group; basal cleavage; soft; pearly; a hydrothermal or weathering alteration of biotite; expands 6 to 20 times by thermal exfoliation; occurs in clay sizes in soils and as crystals and megacrysts in ultramafic rocks; in Montana, North Carolina, South Carolina, Wyoming, Virginia, Colorado, and South Africa. Syn: lernilite vermilion

3492

a. A red pigment used in enormous quantities. Usually made from mercuric sulfide, HgS, tinted with puranitraniline. Also spelled vermillion. Crispin b. A bright-red pigment consisting of mercuric sulfide. Prepared synthetically (as by the reaction of mercury, sulfur, and sodium hydroxide), but formerly obtained from the mineral cinnabar. Color ranges from crimson when coarse grained to nearly orange when finely divided. Both spellings are correct. Webster 3rd c. See: alpha mercuric sulfide; cinnabar; vermeil. vermillion In the Lake Superior region, the lowest of the stratified schists; the crystalline schists. Fay vernadskite Antlerite in aggregates of minute crystals or as pseudomorphs after dolerphanite. See also: antlerite Verneuil process A technique developed by Auguste V.L. Verneuil (1856-1913), French mineralogist and chemist, for the manufacture of large crystals of corundum and spinel in which powdered alumina with appropriate oxide dopants is melted in an oxyhydrogen flame to produce boules of synthetic gems. See also: boule vernier closure meter An instrument used to measure strain. vernier compass A surveyor's compass with a vernier, used for measuring angles without the use of the magnetic needle by means of a compensating adjustment made for magnetic variation. AGI vernier-reading manometer This series of manometers covers a range of pressures from 0.001-in (25.4 mu m) water gage to 40-in (1.02-m) water gage. Syn: micrometer-reading manometer verrankohle Rolled fragments of brown coal found on the coast of Norway. Tomkeieff vertical 3493

a. A term used to define a direction that is perpendicular to a horizontal, or level, plane. AGI b. Local usage for vertical fractures, esp. in the Black Hills, South Dakota. AGI c. Said of deposits and coal seams with a dip of from 60 degrees to 90 degrees . Stoces d. In aerial photographic mapping, a vertical line through the exposure station or rear nodal point. Seelye, 2 e. Orientation of a plumb-bob on a string under the force of gravity. Seelye, 2 vertical aerial photograph A photograph taken from an aircraft for purposes of aerial mapping or aerial geophysical prospecting; special cameras and techniques are employed. See also: profile flying vertical angle Angle of elevation or depression, measured from the true horizontal plane. Seelye, 2 vertical auger drill A mobile-type rotary drill used on opencast sites with no hard rock for drilling vertical blasting holes. It can drill a hole of 5 in or 6 in (12.7 cm or 15.2 cm) in diameter to depths of about 30 ft (9.1 m). Drilling is by means of a rotary cutting head with interchangeable cutting bits, the auger removing the cuttings from the hole. An overall speed of 30 ft/h (9.1 m/h) can be obtained. See also: horizontal auger Nelson vertical balance An instrument for measuring variations in the vertical component of the terrestrial magnetic field, usually by balancing the torque on a magnet system by means of a counter gravitational torque acting on counterweights. AGI vertical chain conveyor Opposed-shelf type that has two or more vertical elevating conveying units opposed to each other. Each unit consists of one or more endless chains whose adjacent facing runs operate in parallel paths. Thus, each pair of opposing shelves or brackets receive objects (usually dish trays) and deliver them to any number of elevations. vertical circle a. Graduated circle on theodolite or tacheometer, by use of which the slope of the collimation line through sighting telescope is measured in survey work. Pryor, 3 b. Any great circle of the celestial sphere passing through the zenith. AGI vertical collimator 3494

An instrument in which the telescope sights vertically (upward or downward); used chiefly for centering a theodolite on a tower exactly over a station mark on the ground. It may be used for any vertical sight. Seelye, 2 vertical component That part, or component, of a vector that is perpendicular to a horizontal or level plane. AGI vertical crater retreat a. A blasting method employed in underground sublevel mining. Initially a vertical slot extending across the width of the stope is mined. The remaining portion of the stope is then blasted by section into the vertical slot following sublevel procedures. SME, 1 b. A variation of the sublevel stoping method that uses basic crater blasting models. Blasting is carried out at the base of vertical boreholes, making horizontal cuts and advancing upwards. A spherical charge is placed at an optimal distance from the stope back so that a maximum volume of rock is broken in the shape of an inverted cone. Borehole spacing is determined so that overlapping fragmentation cones do not disturb adjacent explosive charges. Abbrev. VCR. vertical crater retreat mining A patented mining method in which large, parallel, vertical drillholes permit placement of nearly spherical explosive charges, such that horizontal slices of ore are then broken into an undercut; applicable to ore of only moderate strength. SME, 1 vertical curve a. The curve between two lengths of a straight roadway that possess different gradients. The curve provides a gradual change for haulages from one inclination to the other. The curve leading to the top or brow of an inclined plane would be convex and at the bottom would be concave. Nelson b. The graduated curve connecting two lengths of a railway or road, which are at different slopes. Hammond c. The meeting of different gradients in a road or pipe. Nichols, 1 vertical cut See: shear cut vertical dip slip See: vertical slip vertical drains 3495

Usually column of sand used to vent water squeezed out of humus by weight of fill. Nichols, 1 vertical exaggeration a. A deliberate increase in the vertical scale of a relief model, plastic relief map, block diagram, or cross section, while retaining the horizontal scale, to make the model, map, diagram, or section more clearly perceptible. AGI b. The ratio expressing vertical exaggeration; e.g., if the horizontal scale is 1 in to 1 mi and the vertical scale is 1 in to 2,000 ft, the vertical exaggeration is 2.64. Abbrev: VE AGI c. The apparent increase in the relief as seen in a stereoscopic image. AGI vertical excavation limited area This method of excavation is used in loose or wet soils--unconsolidated formations-where the banks must be supported by shoring or sheathing. The material must, out of necessity, be lifted out vertically. Carson, 1 vertical fold See: upright fold vertical gradient The rate of change of a quantity in the direction of the vertical. vertical gradiometer An instrument for measuring the vertical gradient of gravity. AGI vertical guide idler An idler roller of about 3 in (7.6 cm) in diameter so placed as to make contact with the edge of the belt conveyor should the latter run too much to one side. Although vertical guide rollers are effective, they cause edge wear on the belting and their use is not favored. Nelson vertical intensity The vertical component of the magnetic field; usually considered positive if downward, negative if upward. CF: horizontal intensity vertical line One that is exactly upright, or it points straight up and down. Jones, 2 3496

vertical load-bearing test See: load-bearing test vertical mill A rolling mill in which the rolls are oriented vertically. Osborne vertical photograph An aerial photograph made with the camera axis vertical (camera pointing straight down) or as nearly vertical as possible in an aircraft. AGI vertical pump This pump is often of the single-acting bucket or ram type with single or double cylinders and either with or without a flywheel. Vertical pumps may be used where headroom is adequate but area restricted, although horizontal reciprocating pumps are more generally used. Sinclair, 4 vertical reciprocating conveyor A power or gravity-actuated unit that receives objects on a carrier or car bed usually constructed of a power or roller conveyor. The object is then elevated or lowered to other elevations. vertical sand drain a. A boring through clay or silty soil that is filled with sand or gravel to facilitate drainage of liquid from the soil. Hammond b. See: perched water table vertical screw conveyor A screw conveyor that conveys in a substantially vertical path. See also: screw conveyor vertical seismograph An instrument that registers the vertical component of ground motion. Schieferdecker vertical separation In a fault, the distance measured vertically between two parts of a displaced marker such as a bed. CF: horizontal separation vertical shaft 3497

A shaft sunk at an angle of 90 degrees with the horizon or directly downward toward the center of the Earth. Weed, 2 vertical shear Reference is to a beam, assumed for convenience to be horizontal and to be loaded and supported by forces, all of which lie in a vertical plane. The vertical shear at any section of the beam is the vertical component of all forces that act on the beam to the left of the section. The vertical shear is positive when upward and negative when downward. Roark vertical shift In a fault, the vertical component of the shift. See also: shift AGI vertical slip In a fault, the vertical component of the net slip; it equals the vertical component of the dip slip. CF: horizontal slip Syn: vertical dip slip vertical takeup A mechanism in which the takeup or the movable pulley travels in a vertical plane. NEMA, 2 vertical theory The earliest view of subsidence in which it was supposed that the lines of break (limiting lines) were more or less vertical. Pillars left for support were accordingly formed immediately under the object to be protected, the question of dip being disregarded. Briggs vertical trace A trace on the ground motion record representing the component of motion in a vertical plane and in the direction of the seismic wave travel direction. vesicle A cavity of variable shape in a lava, formed by the entrapment of a gas bubble during solidification. vesicular

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Said of the texture of a rock, esp. a lava, characterized by abundant vesicles formed as a result of the expansion of gases during the fluid stage of the lava. CF: cellular; scoriaceous. AGI vesuvian a. Original spelling of vesuvianite. See also: leucite b. A mixture of calcite and hydromagnesite. Hey, 1 vesuvianite A mineral, Ca10 Mg2 Al4 (SiO4 )5 (Si2 O7 )2 (OH)4 . Tetragonal. Common in contactmetamorphosed limestones. A massive light green variety is known as californite. Syn: idocrase vesuvian jade A jadelike variety of vesuvianite (idocrase). Also called californite. English veszelyite A monoclinic mineral, (Cu,Zn)3 (PO4 )(OH)3 .2H2 O ; greenish-blue. Formerly called arakawaite. Vezin's sampler A mechanical sampling device that automatically selects one twenty-fifth or one sixtyfourth of the ore passing through. Fay V-flume A V-shaped flume, supported by trestlework and used by miners for bringing down timber and wood from the mountains, at the same time using the water for mining purposes. Fay vibracone A vibrating ore screen in which the feed is from a saucer-shaped distributer onto a conical surface kept in vibration by a ratchet motion. Liddell vibrate To have a swinging or oscillating motion; to move or swing back and forth, such as a pendulum does; to have a period of vibration; to fluctuate; to vacillate; to sound, such as a voice vibrates in an ear; to throb. AGI 3499

vibrating conveyor a. A trough or tube flexibly supported and vibrated at relatively high frequency and small amplitude to convey bulk material or objects. See also: oscillating conveyor b. A metal trough mounted on flexible supports and free to move in a vertical plane. It is vibrated at an angle of about 30 degrees to the horizontal. The material being conveyed moves in a series of gentle pitches and catches that blend to produce continuous, uniform flow. There is no tumbling or sliding of the material to cause wear of the trough. There are two basic types of vibrating conveyors: (1) the natural frequency types (those supported by heavy-duty stiff coil or leaf springs), and (2) forced vibration types (those supported by rocker arms or rods pivoted at the trough and at the base connections). Materials can be moved downward, horizontally, or up to 10 degrees slopes. It can convey coal, limestone, sand, coke, granite, gravel, etc. See also: shaker conveyor vibrating coring tube A sediment coring tube designed to vibrate in such a way as to overcome the resistance of compacted ocean floor sediments, sands, and gravel. Hunt vibrating grate A stoker developed in Germany and used increasingly in that country and in the United States. The hearth consists of a rigid water-cooled matrix. Coal is fed on to this at one end and is moved across it by the vibrating motion to discharge as ash at the other end. The vibrations, with an amplitude of about 1/8 in (3 mm) and in progress for about 5 s every 2 min give a satisfactory feed rate. The rate of feed is controlled by altering the duration of the vibrations. See also: stoker; underfeed stoker. Nelson vibrating grease table This type table is used at the Kimberly Mines in South Africa for concentrating the 3.33- to +0.59-mm fraction of pan concentrate and other material of +0.59-mm size. Efficiency is 99%, and the ratio of concentration 50,000:1. vibrating grizzlies Bar grizzlies mounted on eccentrics so that the entire assembly is given a forward and backward movement at a speed of some 100 strokes a minute. This is the type of grizzly now generally used ahead of a primary crusher. Pit and Quarry vibrating platform A loading stage or structure with a double vibrating action that causes the coal or minerals to settle down in a mine car while being loaded. This settlement increases the car-carrying capacity and reduces spillage during transit. Syn: tram vibrator 3500

vibrating screen a. A commercial screen in which the cloth, wire, or bar deck is vibrated by solenoid or by magnetostriction, or mechanically by eccentrics or unbalanced spinning weights. Pryor, 3 b. A screen oscillated either by mechanical or electrical means. The amplitude of movement of the vibrating screen is smaller than that of the jigging screen and its speed of oscillation is higher. BS, 5 c. A screen that is vibrated to separate and move pieces resting on it. Nichols, 1 d. Machines of this type consist of one or more slightly inclined screening surfaces mounted in a robust frame. To increase the capacity and prevent blinding of holes, the screening surfaces are caused to vibrate. This may be done by mounting the screen on powerful springs and causing it to bear down on the underside of the frame. An alternative method used in the Hummer screen is to stretch the wire screen to a high tension and mount an electromagnet actuated by an alternating current at some convenient point on the frame. The magnet works against the springs on which the screen is mounted, and in this way very rapid vibration can be secured and blinding greatly reduced. Miall vibrating screens (heated) Wire-mesh screens that are vibrated and heated electrically to increase efficiency. See also: screens vibrating wire strain gage This consists of a thin steel wire stretched between knife edges, one being free to move longitudinally. The wire is maintained vibrating at its natural frequency by an electrical method. The knife edges are held firmly against the girder under test, a change of strain in the girder varying tension in the wire and hence its natural frequency. This gage is used in conjunction with a reference instrument of fixed frequency; electrical impulses from both instruments are superimposed to produce beats having a frequency equal to the difference between the frequencies of the two instruments. Changes in the frequency of the test gage caused by variations in strain result in identical changes in the beat frequency. The joint output from these two instruments is applied to the plates of a cathode-ray tube, leading to an oscillation of the electron beam with a frequency equal to that of the higher of the two applied frequencies, with an amplitude that increases and decreases with the same frequency as that of the beats. Hammond vibration a. The act of vibrating; oscillation. Vibrations may be free or forced; longitudinal, transverse, torsional, or dilatational; also classified according to kind, such as acoustical, electrical, flexural, etc. AGI b. The undesirable oscillatory movements of a drill string. Long vibration drilling 3501

Drilling in which a frequency of vibration in the range of 100 to 20,000 Hz is used to fracture rock. Ultrasonic drilling is one of the better known methods of vibration drilling. Min. Miner. Eng., 1 vibration gravimeter A device that measures gravity by observation of the period of transverse vibration of a thin wire tensioned by the weight of a known mass; useful for observation at sea. AGI vibration meter A seismometer that is used for measuring vibrations of structures from other than seismic causes. AGI vibration method of roof testing A person's fingertips are placed against the roof, and then the roof is struck a sharp heavy blow. Such a blow usually sets up easily felt vibrations in an unsound roof. vibration of foundations The foundations of machinery installed in a building should be so designed that the frequency of the machine is two times the natural frequency of the combined system of machines and foundations. Hammond vibration test An approximate grading test for coarse-grained soils. A flat paper-covered board is inclined at a slope of 1:24. The dry and powdered sample of soil is spread in a thin layer across the top of the board. The board is tapped sharply and repeatedly. The soil will travel down the board, the largest particles traveling faster and further than the smaller ones. Dependent on the degree in which the soil spreads out, a grading can be allotted to the soil. Nelson vibrator a. A mechanism imparting vibration to screens, concrete consolidators, and shaking tables. b. A tool that vibrates at 3,000 to 10,000 cycles per minute. It can be inserted into wet concrete or attached to formwork to compact the concrete. c. A device for attachment to bins or chutes to produce vibration and thus assist in gravity flow of contained material. vibratory screen

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A sizing screen similar to the shaking screen, but the reciprocating movement imparted to it is of greater frequency and much smaller amplitude--1,000 rpm and 1/4 in (6.4 mm) being typical. High-frequency vibration is more effective than the slow movement of the shaker in preventing blinding of holes, and the screening is more effective. It may contain one, two, or three screen decks with water sprays for washing products when screening. Five products ranging from plus 3/4 in (19.1 mm) to minus 1/8 in (3.2 mm) are possible from a double-deck screen. In general, the screen is inclined at from 12 degrees to 14 degrees for the coarser sizes and 17 degrees to 21 degrees for the finer sizes with counterflow operation. See also: pool washing screen; varislope screen. Nelson Vibrex grease table A device to concentrate and separate diamonds from gangue material. It is based on the principle that short, sharp vibrations in rapid succession transmitted to a greased surface cause diamonds to become imbedded in the grease, while water washes away other materials. Vibroflotation The trade name for a geotechnical process that uses vibration to compact clean sands and gravels. The vibration is combined with a water jet to give a high degree of compaction. Hammond vibrograph An instrument for recording the ground vibrations caused by heavy quarry blasts. The relationship between the amount of vibration, the distance from the blast, and the weight of explosive fired may be expressed thus: A = (KE)/D, where A = maximum amplitude in thousandths of an inch; K = constant depending on the quarry site; E = weight of explosive in pounds; and D = distance in feet. The constant K can be determined by firing a specimen blast of a given size at a given distance and measuring the amplitude of the record obtained. Amplitudes in excess of 0.04 in (1 mm) may give rise to damage. A movement of 0.008 in (0.2 mm) can be felt, and if used an excessive number of times may give rise to complaints of nuisance and damage. Short-delay blasting methods with small diameter holes reduce vibration hazards. See also: falling-pin seismometer; seismograph. Nelson vicinal face a. One of the facets modifying normal crystal faces; they usually lie nearly in the plane of the face they modify. CMD b. One of the crystal faces with complex Miller indices in apparent violation of the Bravais law requiring high densities of lattice points parallel to prominent faces. Vicinal faces are small and diverge from major faces by very small angles. Syn: vicinal form 3503

vicinal form See: vicinal face Vickers' diamond hardness tester A small impression machine, capable of testing very hard metals, finished components, and very thin sheets. The diamond is similar to that used in the diamond pyramid hardness test. The duration of application of the load is controlled automatically, being always applied and removed in exactly the same manner. This machine may also be used with a ball indenter for the Brinell hardness test. Hammond Vickers hardness test A test of resistance to deformation of metals or minerals in which a pyramid-shaped diamond is forced into a polished surface of the specimen to be tested under various static loads. The result is a function of the average length of the diagonals of the resulting indentation. CF: Tukon hardness test; Brinell hardness test. AGI victualic coupling A development in which a groove is cut around each end of a pipe instead of the usual threads. Two ends of pipe are then lined up and a rubber ring is fitted around the joint. A pair of semicircular bands, forming a sleeve, are placed around the ring and are drawn together with two bolts. These have a ridge on both edges that fits into the groove of the pipe. As they are tightened, the rubber ring is compressed, making a watertight joint, while the ridges fitting in the grooves make it strong mechanically. Victualic pipe is faster to lay because in large sizes it does not have to be aligned perfectly and screwed in. Kentucky victualic joint A proprietary pipe joint that allows the pipes to move through several degrees after fixing but yet to remain watertight. This joint is designed to allow about 12 degrees of movement without causing leakage. The pipes have specially shouldered ends that are contained by a circumferential rubber washer held by a special circumferential-type flange. The water has access to the inner part of the washer, on which it exerts pressure and thereby seals the joint. Hammond; Mason Vielle-Montagne furnace A mechanical roasting furnace similar to the Ross and Welter type. Fay Vienna turquoise 3504

An amorphous turquoise imitation once manufactured in Austria, Czechoslovakia, France, and England. Having approx. the same chemical composition, hardness, density, and fracture, it is more difficult to detect than the various blue-stained minerals since used as turquoise substitutes. vierendeel girder An open-frame N-truss without diagonal members, with rigid joints between the top and bottom chords and the verticals. Known also as open-frame girder. Hammond viese Scot. The line of fracture of a fault or the soft earth in a fissure or on the sides of a fault. Also spelled vise. vignite A magnetic iron ore. Fay vigorite An explosive resembling dynamite No. 2 and consisting of nitroglycerin with a more or less explosive dope. Fay Vigorite No. 5 Permissible explosive; used in mines. Also called L.F. Vigorite No. 5. Bennett villamaninite An isometric mineral, (Cu,Ni,Co,Fe)(S,Se)2 ; pyrite group; forms small iron-black cubooctahedra and radiating nodular masses; at Villamin, Spain. Villela's reagent An etching reagent consisting of 95 ml of ethyl alcohol, 5 ml of hydrochloric acid, and 1 g of picric acid. Osborne villiaumite An isometric mineral, NaF ; soft; deep carmine; forms small crystals and grains in nepheline syenite; in Islands of Los, Guinea. vinney 3505

Copper ore, with a green efflorescence like verdigris. Fay vinogradovite A monoclinic mineral, (Na,Ca,K)4 Ti4 AlSi6 O23 (OH).2H2 O ; white to colorless; forms crystals and spherical aggregates in nepheline syenite in the Kola Peninsula, Russia. vinyl acetal resins Prepared from polyvinyl acetate. Properties are toughness, adhesiveness, imperviousness to moisture, and stability toward light and heat. Used as an interlayer in safety glass and as a bonding resin. Crispin violaite A highly pleochroic variety of clinopyroxene found in the Caucasus Mountains, Russia. violan A violet variety of diopside found at St. Marcel, Piemont, Italy. violite See: copiapite virgate To branch in diverging lines. Webster 3rd virgation a. A divergent, branchlike pattern of fault distribution. The term is used in Russian literature. AGI b. A fold pattern in which the axial surfaces diverge or fan out from a central bundle. AGI c. A sheaflike pattern, as shown on a map, of mountain ranges diverging from a common center. Ant: syntaxis. AGI virgin a. Unworked or untouched; said of areas where there has been no mining. Mason b. An unexploited area or rock formation in which boreholes have not been drilled. Long c. See: primary metal virgin clay Fresh clay, as distinguished from that which has been fired. AGI 3506

virgin coal An area of coal that is in place (in situ) and unimpaired by mining activities. Nelson virgin metal Pure metal obtained directly from ore. See also: primary metal ASM, 1; Newton, 1 viridine A green manganese-rich variety of andalusite. viridite a. A ferruginous chlorite in chloritic iron ore. b. A general term formerly applied to indeterminable and obscure green alteration products occurring in scales and threads in the groundmass of porphyritic rocks. virtual value The calibration of alternating current instruments is based upon what is called the virtual value, and this corresponds to the direct-current value, which would produce the same heating effect in a given resistance. The peak value of alternating voltage or current is 1.4 times greater than the virtual value. Mason viscometer An instrument used to measure the viscosity. Syn: viscosimeter AGI viscosimeter See: viscometer viscosity The property of a fluid to offer internal resistance to flow; its internal friction. Specif., the ratio of the shear stress to the rate of shear strain. AGI viscosity coefficient A numerical factor that measures the internal resistance of a fluid to flow; it equals the shearing force in dynes per square centimeter transmitted from one fluid to another that is 1 cm away, and generated by the difference in fluid velocities of 1 cm/s in the two planes. The greater the resistance to flow, the larger the coefficient. Syn: absolute viscosity; dynamic viscosity. AGI 3507

viscountess Building slate 18 in by 10 in (45.7 cm by 25.4 cm). Pryor, 3 viscous a. Adhesive or sticky, having a ropy or glutinous consistency. Webster 3rd b. Imperfectly fluid; designating a substance that, like tar or wax, will change its form under the influence of a deforming force, but not instantly, as more perfect fluids do. Standard, 2 viscous damping Viscous damping is the dissipation of energy that occurs when a particle in a vibrating system is resisted by a force the magnitude of which is a constant, independent of displacement and velocity, and the direction of which is opposite to the direction of the velocity of the particle. Hy viscous flow A type of fluid flow in which there is a continuous steady motion of the particles; the motion at a fixed point always remains constant. Also called streamline flow; laminar flow; steady flow. CTD viscous resistance The effect of surface friction between a particle and a liquid when the particle moves through the liquid. CF: turbulent resistance Newton, 1 Visean Upper Lower Carboniferous. AGI viseite An isometric mineral, Ca10 Al24 (SiO4 )6 (PO4 )7 O22 F3 .72H2 O(?) ; white; forms wartlike masses; at Vise, Belgium. visibility meters The general principle of such meters is to observe a portion of the visual field against its background and then to bring about a condition such that the observed difference in brightness reaches a threshold value so that it is only just discernible. The instruments differ in their means by which this end is achieved. The threshold may be produced quite simply by interposing a light-absorbing medium, such as an optical wedge, in the field 3508

of view. Other methods include reducing the contrast between the object and its background by superimposing a veiling brightness over the observed field. Roberts, 2 visible light a. The light of the visible spectrum. b. Electromagnetic radiation, with wavelength range approx. 4,000 to 7,000 Aa, which a normal human eye can detect. CF: invisible light; ultraviolet; infrared. visible spectrum That portion of the electromagnetic spectrum in which the waves normally produce, upon the human eye, color sensations of red, orange, yellow, green, blue, violet, or their intermediate hues, or of white light if the rays are combined. Distinguished from radio, infrared, ultraviolet, gamma, and X-rays. Vissac jig An air-operated pulsator jig in which air is alternately compressed and allowed to expand to produce pulsation. This jig has been used principally on sized bituminous coal. Mitchell visual indicator A device by which the winding or haulage engineman can see on a dial or panel the position of the cages in a shaft or the journey on the haulage plane. See also: depth indicator Vitasul A trade name for a chemical additive that eliminates or reduces considerably the danger of diesel locomotive fumes underground. Tests have established that the chemical, added to diesel fuel, reduces the carbon-monoxide danger from diesel locomotive exhausts to negligible proportions. Nelson vitiated air Air that has been rendered impure by the breath of workers and horses, or by being mixed with the various gases given off in mines. It is frequently called return air. Peel vitrain a. Designation of macroscopically recognizable, very bright bands of coals. Very bright bands or lenses, usually a few millimeters (3 to 5) in width; thick bands are rare. Clean to the touch. In many coals, the vitrain is permeated with numerous fine cracks at right 3509

angles to stratification and consequently breaks cubically, with conchoidal surfaces. In other coals, the vitrain is crossed by only occasional perpendicular cracks. In the macroscopic description of seams, only the bands of vitrain having a thickness of several millimeters are usually noted. Examination with the microscope shows vitrain to consist of microlithotypes very rich in vitrinite. After clarain, vitrain is the most widely distributed and common macroscopic constituent of humic coals. Occurs in lenticular bands, each derived from a single piece of original vegetable growth. When it constitutes 30% to 60% of total seam, it is termed abundant; more than 60%, dominant; between 15% and 30%, moderate; below 15%, sparse. IHCP; Pryor, 3 b. A coal lithotype characterized macroscopically by brilliant, vitreous luster, black color, and cubic cleavage with conchoidal fracture. Vitrain bands or lenticles are amorphous, usually 3 to 5 mm thick, and their characteristic microlithotype is vitrite. CF: clarain; durain; fusain; vitrite. Syn: pure coal vitreous a. In minerals, a luster typical of that of quartz or calcite. CF: adamantine; pearly; resinous. b. That degree of vitrification evidenced by low water absorption. See also: impermeable; nonvitreous; semivitreous. ASTM c. Amorphous. d. Noncrystalline, such as volcanic glass. e. Consisting of or resembling glass. Kinney vitreous copper See: chalcocite vitreous copper ore See: chalcocite vitreous fusion Gradual fusion; having no sharp melting point. Webster 3rd vitreous silica Silica glass. vitreous silver See: argentite vitric Said of pyroclastic material that is characteristically glassy; i.e., contains more than 75% glass. AGI 3510

vitrics a. Fused siliceous compounds, such as glasses and enamels, as distinguished from ceramics, or fused aluminous compounds. Standard, 2 b. The art or history of glass production. Standard, 2 vitric tuff A tuff that consists predominantly of volcanic glass fragments. CF: crystal tuff; crystalvitric tuff. AGI vitrifacture The manufacture of vitreous or vitrified wares, as glass. Standard, 2 vitrifiable Of or pertaining to a substance that can be vitrified. Webster 3rd vitrification An act, or instance, or the process of vitrifying or making glassy; the condition of being vitrified; a vitrified body. Webster 3rd vitrification spalling That resulting directly or indirectly from the permanent physical changes caused by vitrification. vitrified a. That characteristic of a clay product resulting when the temperature in a kiln is sufficient to fuse all the grains and close all the pores of the clay, making the mass impervious. ACSG, 1 b. Converted into glass. Kinney vitrified brick A very hard paving brick burned to the point of vitrification and toughened by annealing. Crispin vitriform Having the form or the appearance of glass; glassy. Webster 3rd vitrify 3511

To change into glass or into a glassy substance by heat and fusion. To make vitreous; esp. to produce (as in a ceramic ware) enough glassy phase or close crystallization by high-temperature firing to make nonporous. To undergo vitrification or vitrifaction; to become vitreous. Webster 3rd vitrifying A stage in the heating of a clay when some of the ingredients have melted and have partially or completely closed the pores, as in stoneware and porcelain. The completion of this stage occurs at the point of maximum shrinkage without loss of shape. See also: baking; squotting. Nelson vitrinertite A coal microlithotype that contains a combination of vitrinite and inertinite totalling at least 95%, and containing more of each than of exinite. It generally occurs in highranking bituminous coals. AGI vitrinite A group name comprising collinite and telinite. Differentiation between collinite and telinite depends in part on the method of observation. The distinction is more easily made in thin section or after etching a polished surface. Often there is uncertainty of distinction by reflected light, and in such cases, it is proper to use the general term vitrinite. See also: collinite; telinite. IHCP vitrinization The process in coalification that results in the formation of vitrain. See also: coalification vitrinoid Vitrain and similar material in coal. AGI vitriol A sulfate of any of various metals (such as copper, iron, or zinc,); esp. a hydrate (as the heptahydrate) of such a sulfate having a glassy appearance or luster. Webster 3rd vitriol ocher See: glockerite vitrite 3512

A coal microlithotype group that contains vitrinite macerals totalling at least 95%. CF: liptite; vitrain. AGI vitroPrefix meaning glassy. vitroclarain A rock-type coal consisting of vitrinite (collinite or telinite) and other macerals, mainly exinite, and in which the other macerals exceed vitrinite in quantity. CF: clarovitrain vitroclastic Pertaining to a pyroclastic rock structure characterized by fragmented bits of glass; also, said of a rock having such a structure. AGI vitrodurain Durain in which much vitrain is present. Judged obsolete by the Heerlen Congress of 1935. CF: durovitrain vitrofusain A coal constituent transitional between vitrain and fusain, and showing plant cell structure. The cell walls are soaked with vitrain, where the cell cavities are empty. It is not a mixture but a transition. Accepted by the Heerlen Congress of 1935 to designate material transitional between vitrain and fusain with fusain being predominant. CF: fusovitrain AGI vitrophyre Any porphyritic igneous rock having a glassy groundmass. Adj: vitrophyric. CF: felsophyre; granophyre. Syn: glass porphyry vitrophyric Said of a porphyritic igneous rock having large phenocrysts in a glassy groundmass. AGI vivianite a. A monoclinic mineral, 2[Fe3 (PO4 )2 .8H2 O]; colorless where fresh; turning blue on oxidation; soft; a secondary mineral found in ore deposits and pegmatites, in clays associated with bone and other organic remains, and in anaerobic lake sediments. Syn: 3513

blue iron earth; blue ocher; Prussian blue. b. The mineral group annabergite, baricite, hoernesite, koettigite, parasymplesite, and vivianite. vlasovite A monoclinic and triclinic mineral, Na2 ZrSi4 O11 ; forms colorless crystals in the contact zone of the Lovozero massif, Kola Peninsula, Russia. It is related to narsarsukite. V-method of roasting The introduction of a supplementary roast heap between each two regular heaps, so that, if left untouched, there would be a continuous and unbroken roast heap the entire length of the roast yard. Fay vogesite A lamprophyre composed of hornblende phenocrysts in a groundmass of alkali feldspar and hornblende. Clinopyroxene, olivine, and plagioclase feldspar also may be present. Vogesite contains less biotite than minette. The name, given by Rosenbusch in 1887, is for the Vosges Mountains, France. AGI vogle See: vug voglianite a. A soft, green, basic uranium sulfate, found in nodules or as earthy coatings. Standard, 2 b. Validity of species is doubtful. All existing specimens, upon examination, have proved to be cuprosklodowskite. Crosby; Dana, 2 c. A variety of zippeite(?). voglite A monoclinic mineral, Ca2 Cu(UO2 )(CO3 )4 .6H2 O(?) ; strongly radioactive; emerald to grass green; an alteration product of uraninite associated with liebigite. void a. A general term for pore space or other openings in rock. In addition to pore space, the term includes vesicles, solution cavities, or any primary or secondary openings. Syn: pore; interstice. AGI b. That portion of a borehole from which the core could not be recovered. Long void ratio 3514

The ratio of the volume of void space to the volume of solid substance in any material consisting of voids and solid material, such as a soil sample, sediment, or sedimentary rock. Symbol e. Syn: voids ratio AGI voids ratio See: void ratio vol See: vole volatile Readily vaporizable. AGI volatile combustibles See: volatile matter volatile fluxes The volatile constituents of a magma. volatile matter In coal, those substances, other than moisture, that are given off as gas and vapor during combustion. Standardized laboratory methods are used in analysis. Syn: volatiles; volatile combustibles. AGI volatile ratio In coal, the ratio of the volatile matter to the sum of the volatile matter and the fixed carbon. Federal Mine Safety volatiles The volatile constituents (or rest magma) remaining after the less volatile ores have crystallized as igneous rocks. Syn: volatile matter AGI volborthite A monoclinic mineral, Cu3 V2 O7 (OH)2 .2H2 O ; radioactive; has one perfect cleavage; dark olive to yellow-green; a secondary mineral with carnotite in sandstone. Syn: uzbekite 3515

volcanic Characteristic of, pertaining to, situated in or upon, formed in, or derived from volcanoes. See also: extrusive volcanic ash See: ash volcanic breccia a. A pyroclastic rock that consists of angular volcanic fragments that are larger than 64 mm in diameter and that may or may not have a matrix. AGI b. A rock that is composed of accidental or nonvolcanic fragments in a volcanic matrix. Syn: alloclastic breccia; lava breccia. AGI volcanic clay See: bentonite volcanic conglomerate A water-deposited conglomerate containing more than 50% volcanic material, esp. coarse pyroclastics. AGI volcanic dust See: ash volcanic earthquake A seismic disturbance that is due to the direct action of volcanic force, or one whose origin lies under or near a volcano, whether active, dormant, or extinct. AGI volcanic focus The subterranean seat or center of volcanism of a region or of a volcano. AGI volcanic glass A natural glass produced by the cooling of molten lava, or a liquid fraction of it, too rapidly to permit crystallization. Examples are obsidian, pitchstone, tachylyte, and the glassy mesostasis of many extrusive rocks. CF: glass volcanicity 3516

See: volcanism volcanic ore deposits The major group of ore deposits of magmatic origin, designated as young by European mineralogists, which have been formed under near-surface conditions and very often in Tertiary or younger volcanic rocks. In a strict sense, deposits formed in relation to surface eruptions. Schieferdecker volcanic plain Surface formed by extensive lava or ash flows that cover topographic irregularities. AGI volcanic rift zone See: rift zone volcanic rock a. A generally finely crystalline or glassy igneous rock resulting from volcanic action at or near the Earth's surface, either ejected explosively or extruded as lava; e.g., basalt. The term includes near-surface intrusions that form a part of the volcanic structure. Syn: volcanite AGI b. A general term to include the effusive rocks and associated high-level intrusive rocks; they are dominantly basic. AGI volcanics A general collective term for extrusive igneous and pyroclastic material and rocks. volcanic water Water in, or derived from, magma at the Earth's surface or at a relatively shallow level; juvenile water of volcanic origin. AGI volcanism The processes by which magma and its associated gases rise in the crust and are extruded onto the Earth's surface and into the atmosphere. Also spelled vulcanism. Syn: volcanicity volcanite An obsolete term variously used to denote a volcanic rock and selenian sulfur. volcano 3517

a. A vent in the surface of the Earth through which magma and associated gases and ash erupt; also, the form or structure, usually conical, that is produced by the ejected material. AGI b. Any eruption of material; e.g., mud, that resembles a magmatic volcano. Obsolete var; vulcano. Pl: volcanoes. Etymol: the Roman deity of fire, Vulcan. AGI volchonskoite See: volkonskoite vole The place where tin ore is stored to be dried before being put into a smelting furnace. Syn: vol voler reductol A lubricant for enclosed gear units; composed of high-quality mineral oil with a suspension of superfine colloidal graphite and silicone foam inhibitor. Nelson volgerite A discredited term equal to stibiconite. Am. Mineral., 1 volkonskoite A monoclinic mineral, Ca0.3 (Cr,Mg,Fe)2 (Si,Al)4 O10 (OH)2 .4H2 O ; smectite group. Also spelled volchonskoite. volley The act of exploding blasts in sections. A round of holes fired at any one time. Standard, 2; Fay volt The practical meter-kilogram-second (mks) unit of electrical potential difference and electromotive force (emf) that equals the difference of potential between two points in a conducting wire carrying a constant current of 1 A when the power dissipated between these two points equals 1 W. It equals the potential difference across a resistance of 1 Omega when 1 A of current is flowing through it; the standard in the United States. Webster 3rd voltage Electromotive force. Nichols, 1 3518

voltaite An isometric mineral, K2 Fe9 (SO4 )12 .18H2 O ; has both ferric and ferrous iron. Volta's list A list or series of metals, such that any one will be at a higher electrical potential when put in contact with any of those that follow, and at a lower potential if in contact with any metal before it in the series. Fay voltmeter An instrument for determining voltage. Crispin voltzite Wurtzite mixed with an organometallic zinc compound. volume defect A crystal structure deviating from ideality by having two or more chemical species in one or more crystal sites. CF: crystal defect; disorder. volume susceptibility See: susceptibility volumetric Chemical analysis based upon the reaction of a volume of standard solution with the material being analyzed. ASTM volumetric analysis Quantitative chemical analysis in which known weight of sample is dissolved and reacted with a standard chemical solution of strength proportional to its normality or hydrogen equivalent. Completion of reaction (end point) is judged by change of color, incipient precipitation, or effect on an indicator. See also: dry assay; wet assay. Pryor, 3 volumetric efficiency a. The ratio of the total quantity of air passing along the faces to the quantity flowing in the fan drift. See also: overall ventilation efficiency; surface air leakage. Roberts, 1 b. The ratio of the volume of air discharged to the displacement for a fan or compressor. 3519

Hartman, 2 c. The volume of water that enters a pump cylinder for each piston stroke divided by the volume swept by the piston (piston area times stroke). Nelson volumetric shrinkage The decrease in volume, expressed as a percentage of the soil mass when dried, of a soil mass when the water content is reduced from a given percentage to the shrinkage limit. Also called volumetric change. ASCE volute a. A spiral casing to a mine fan to provide an area of passage, which gradually increases in proportion to the increasing area of discharge from the fan. See also: evase b. A spiral casing for a centrifugal pump or a fan designed so that speed will be converted to pressure without shock. Hammond volute pumps This type of centrifugal pump is the most commonly used. The impellers may be open, closed or semienclosed, single suction, double suction, or nonclogging. They discharge into casings that are progressively expanding spiral designs of one or more stages (multistage). The casings housing the rotating elements may be vertically or horizontally split, and a few designs have casings divided on an angle from the horizontal. Pumps in this class usually have a specific speed below 4,000 rpm with single-suction impellers and a specific speed of 5,000 rpm with double-suction impellers. Pit and Quarry von Neumann spike The pressure peak leading the detonation wave prior to the establishment of the C-J state. Van Dolah vonsenite An orthorhombic mineral, Fe3 BO5 ; ludwigite group; contains both ferrous and ferric iron with ferrous iron replaced by magnesium toward ludwigite; black; forms coarse granular masses; at Riverside, CA. von Sterneck-Askania pendulum A device for measuring the vertical component of gravity, characterized by the use of four pendulums in a single case. AGI von Wolff's classification

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A quantitative chemical-mineralogic classification of igneous rocks proposed in 1922 by F. von Wolff. AGI vooga hole See: vug Vooys process A coal-cleaning process using a heavy suspension, consisting of clay and finely ground barite (-150 or #MG200 mesh) in water. A coal containing as little as 3.3% to 3.4% ash is steadily produced, with a yield practically equal to the theoretical float-and-sink yield. Gaudin, 1 vorobievite A white or rose-colored variety of beryl from the Ural Mountains, Russia, and Madagascar. Syn: morganite vortex finder Tube projecting into central vortex of hydrocyclone or dense medium cyclone through which the classified fines or lighter specific gravity fraction of pulp leaves the system. vraibite An orthorhombic mineral, Tl4 Hg3 Sb2 As8 S20 ; forms gray-black crystals or thin red splinters; commonly intergrown with realgar and orpiment; occurs at Salonika, Macedonia, Greece. vug A small cavity in a rock, usually lined with crystals of a different mineral composition than the enclosing rock. Adj: vuggy. CF: druse; miarolitic cavity; geode. Syn: bug hole; vogle; vooga hole. See also: cavity; vuggy porosity; loch. Etymol: Cornish vooga, cavern or cavity. vugg A misspelling of vug. Long vuggy Pertaining to a vug or having numerous vugs. Syn: vugular 3521

vuggy lode A lode or vein in which vugs or drusy cavities are of frequent occurrence. Fay vuggy porosity Porosity due to vugs in calcareous rock. The term vugular is used by some writers but condemned by others. See also: vug vugh-arching When a pocket of rock in the periphery of an excavation is weaker than the remainder, it may fail under the ring stress. Fragments split away or fall out until all the weak rock is removed, forming an artificial vugh. This is called vugh-arching. Spalding vug hole See: vug vugular See: vuggy vulcan coal powder Explosive; used in mines. Bennett vulcanism Volcanism. vulcanite a. An orthorhombic mineral, CuTe ; with rickardite and native tellurium, it forms coatings on rocks; occurs at the Good Hope Mine, Vulcan, CO. b. A dark-colored, hard variety of vulcanized India rubber that differs from the softer rubber in having been vulcanized at a high temperature; ebonite. It takes a high polish, and is used for making combs, ornaments, etc., and in electrical work because of its fine insulating properties. Standard, 2 vulcanites A general name for igneous rocks of fine grain size, normally occurring as lava flows, and thus in direct contrast with plutonites. CTD 3522

vulcanized rubber A rubber that has been heated with sulfur to change its properties. Nelson vulcanizing machine Consists essentially of two heavy metal plattens that are placed one on each side of the previously prepared joint and clamped firmly together. Each platten is heated, and this combined application of heat and pressure over a period completes the joint. These machines are used to vulcanize the belt joints of conveyors. vulcan powder High explosive composed of 30% nitroglycerin, 52.5% sodium nitrate, 10.5% charcoal, and 7% sulfur. Pryor, 3 vulpinite A scaly, granular variety of anhydrite; may be admixed with silica; cut and polished for ornamental purposes. V-vat a. A funnel box; also, having a groove or grooves of a triangular section. Webster 2nd b. See: spitzkasten vysotskite A tetragonal mineral, (Pd,Ni)S ; isomorphous with braggite; in minute grains or prisms; at Norilsk, Russia.

W W.8 methanometer A dual-scale, direct-reading instrument for measuring the combustible gases percentage in mine air. It gives combustible gases readings over the range from 0.2% to 5% and is graduated 0.1% per division on the scale. Nelson wabanite Banded cream to black and gray to purple chocolate-colored slate from Massachusetts. Schaller 3523

wacke a. A dirty sandstone that consists of a mixed variety of angular and unsorted or poorly sorted mineral and rock fragments, and of an abundant matrix of clay and fine silt; specif. an impure sandstone containing more than 10% argillaceous matrix. The term is used for a major category of sandstone, as distinguished from arenite. AGI b. A clastic sedimentary rock in which the grains are almost evenly distributed among the several size grades; e.g., a sandstone consisting of sediment poured in to a basin of deposition at a comparatively rapid rate without appreciable selection or reworking by currents after deposition, or a mixed sediment of sand, silt, and clay in which no component forms more than 50% of the whole aggregate. AGI c. A term commonly used as a shortened form of graywacke. This usage is not recommended. AGI d. Originally, a term applied to a soft earthy variety of basalt, or to the grayish-green to brownish-black claylike residue resulting from the partial chemical decomposition of basalts, basaltic tuffs, and related igneous rocks. Syn: vake mining term signifying a large stone or stoniness in general. AGI wacken Rocklike clay, formed by the decomposition of basalts in situ. CF: graywacke wad a. An earthy, dark brown to black mineral material consisting chiefly of an impure mixture of manganese oxides and oxyhydroxides with variable amounts of copper, cobalt, and iron oxides and oxyhydroxides and silica plus 10% to 20% adsorbed water. It is commonly soft (soiling hands), but may be hard and compact, and has a low density. Wad results from the decomposition of other manganese minerals and accumulates in marshy areas or other zones of ground-water emission where it is an ore of manganese. See also: asbolan earthy manganese; manganese hydrate. b. A general term for massive, fine-grained manganese oxides and oxyhydroxides of low density, but not further identified. c. In drilling, a term applied to rock cuttings that tend to ball and adhere to drill-string equipment and borehole walls in lumps. Long wad coil Eng. A tool for extracting a pebble or broken tool from the bottom of a borehole. It consists of two spiral steel blades arranged something like a corkscrew. See also: spiral worm wadding Paper or cloth placed over explosives in a hole. Nichols, 1 Waddle fan 3524

An earlier type of centrifugal fan. It had no external casing, but delivered directly to the atmosphere all around its periphery. The veins were curved backwards in the direction of rotation and the air was led into the fan by a curved inlet passage or throat. It was usually driven by steam at about 70 rpm; efficiency about 40%; external diameter of about 30 ft (9.1 m). See also: Sirocco fan wadeite A hexagonal mineral, K2 CaZ.(SiO3 )4 ; forms hexagonal plates; in Western Australia. wad hook See: wad coil; spiral worm. wadi a. A term used in the desert regions of Southwestern Asia and Northern Africa for a stream bed or channel, or a steep-sided and bouldery ravine, gully, or valley, or a dry wash, that is usually dry except during the rainy season, and that often forms an oasis. AGI b. The intermittent and torrential stream that flows through a wadi and ends in a closed basin. AGI c. A shallow, usually sharply defined, closed basin in which a wadi terminates.---Etymol: Arabic. Variant plurals: wadis; wadies; wadian; widan. See also: arroyo; nullah. Also spelled: wady; waddy. Syn: oued; widiyan. AGI Waelz process A process by which low-grade ores, slags, or residues from retorts may be treated either for the recovery of zinc alone or for the recovery of zinc, lead, and tin. It employs a rotary kiln, and the zinc-bearing material mixed with fine coal is fed into the kiln and heated, so that the zinc is vaporized and converted to oxide fume. Newton, 1 wafer a. A name given to the rough slice obtained by sawing directly from a mother crystal or section. The process of manufacturing wafers is variously known as wafering, wafering from the crystal or slab, wafering from the mother crystal, and baloney slicing. Am. Mineral., 2 b. Small sheet of electroceramic material 0.001 to 0.01 in (0.025 to 0.25 mm) thick for use in electronic equipment, particularly in miniature capacitors, transistors, resistors, and other circuit components. waggon See: wagon wagnerite 3525

A monoclinic mineral, (Mg,Fe)2 (PO4 )F ; magnesium is replaced by ferrous iron or calcium; imperfect cleavage. wagon a. An underground coal car. Korson b. A mine car. c. Any vehicle for carrying coal or debris. Mason d. A trailer with a dump body. Nichols, 1 wagon arrester An appliance that can bring a wagon completely to rest and is usually used near the departure end of mine sidings. It can be rendered inoperative by remote control if required. Nelson wagon booster-retarder An appliance that reduces the speed of wagons traveling above the design value, but for wagons traveling at speeds less than this, it releases energy by thrusting against the wheel flanges, therefore speeding up the vehicle. See also: wagon retarder wagon breast a. Rooms or wide coal roadways into which mine cars or wagons are taken. Nelson b. A pillar method of working a relatively thick, flattish coal seam. Nelson wagon drill A drilling machine mounted on a light, wheeled carriage. BS, 12 wagon pinch bar A device for moving railway wagons and locomotives short distances by hand. It consists of a cast-steel wedge-shaped tip with a wood handle. The tip is placed over the rail and under the wagon wheel and the up-and-down movement of the handle exerts sufficient pressure on the wheel to move the wagon. Nelson wagon rerailer A device for bringing a derailed wagon back onto the track. It usually consists of ramp elements, which can be fixed at intervals along the track or temporarily fitted to the track just beyond the end of the wagon. The wagon is then pulled to cause the wheels to ride up the ramp and back on to the rails. Nelson wagon retarder 3526

An appliance that reduces the speed of a wagon traveling in excess of a designed value (e.g., 3-1/2 mph), while having no effect on wagons moving at speeds less than this figure. The appliance is a self-contained hydraulic unit. Nelson wagon rooms Rooms driven in inclined seams in such a way that an adequate gradient is secured for cars, which are often hauled to the heads of the rooms. Stoces wagon spotter A wagon spotting appliance. It may be a "bogey" that is hauled backwards and forwards on a separate track installed between the main track rails by a winch. A forward pull on the bogey raises a pair of arms to engage in the wagon axle, and a reverse pull lowers the arms to enable the bogey to be drawn back under the next wagon ready for the next pull. Nelson wagon tippler A power-operated structure for discharging coal or other material from a railway wagon. Nelson wairakite A monoclinic mineral, CaAl2 Si4 O12 .2H2 O ; zeolite group; pseudocubic; colorless to white; in tuffaceous rocks in geothermal areas. wairauite An isometric mineral, CoFe ; forms minute grains with awaruite in the Red Hills serpentines; at Wairau, South Island, New Zealand. waiver Involves the notion of an intention entertained by the holder of some right, to abandon or relinquish instead of insisting on the right. It is a question of fact. Proof of waiver must include proof of knowledge of the facts upon which the waiver is based. Ricketts Wakefield sheet pile Consists of three boards bolted or spiked together with the center board offset. This arrangement produces a tongue and groove that makes Wakefield sheet piling fairly watertight if the piles are properly driven and tightly fitted together. Urquhart walaite 3527

A variant spelling of valaite. Tomkeieff walchowite A honey-yellow variety of retinite containing little nitrogen, occurs in brown coal at Walchow, Moravia, Czech Republic. waling Eng. Cleaning coals by picking out refuse. walk To deviate from the intended course, such as a borehole that is following a course deviating from its intended direction. Also called deviating; war; wandering. Syn: walking Walker balance A type of counterpoised beam balance. CF: Westphal balance walker's earth See: fuller's earth walking a. The movement forward or backward of a dredge by first winding up on one side and then the other, swinging the boat from side to side and thereby advancing with a slight offsetting to the side. Fay b. See: walk walking bar A trunnion or walking beam. Nichols, 1 walking beam a. The beam used to impart a reciprocating movement to the drilling column in percussive drilling. Syn: oscillating beam; rocking beam. BS, 9 b. On cable tool and churn drill rigs, the beam that carries the string of drilling tools at one end and is connected to a cranked drive wheel at the other. The rotation of the wheel causes the tool string to lift and drop; thus the hole is drilled by concussion. Long walking crane 3528

A light crane traveling on an overhead channel iron and a single rail vertically beneath this in the floor. Webster 3rd walking dragline a. A dragline that is equipped with apparatus that permits it to "walk" by the alternate power movement of vertical booms fastened to large outrigger platforms so arranged as to push the equipment forward as work progresses. BCI b. An excavator of very large capacity, equipped with walking beams operated by eccentrics in place of crawler tracks. Such machines can excavate 1,650 st/h (1,500 t/h) of overburden to a depth of 100 ft (30 m). Hammond walking miner See: joy walking miner. walking props See: self-advancing supports walking support See: self-advancing supports walkout Act of walking out or leaving; specif., a labor strike. Webster 2nd wall a. The side of a level or drift. Fay b. The country rock bounding a vein laterally. The side of a lode; the overhanging side is known as the hanging wall and the lower lying side as the footwall. See also: hanging wall; footwall. Syn: walls of a vein Fay c. The face of a longwall working or stall, commonly called a coal wall. Fay d. A rib of solid coal between two rooms; also, the sides of an entry. BCI wall accretions Material adhering to the inner walls of a blast furnace between the water jackets and the feed door. Fay Wallace agitator Mixing device, driven by an impeller, used in pulp mixing and aeration in cyanidation where strong agitation is needed. Pryor, 3 3529

wall boss a. A person who supervises a crew of workers operating a face conveyor. Hess b. See: room boss wall cake See: cake wall cavitation The development of enlarged sections in a borehole as the result of caving, erosive action of the circulated liquid, or erosion caused by drill rods rubbing against the borehole walls. Long wall clearance The distance between the wall of the borehole and the outside of a piece of drill-string equipment when the string is centered in the borehole. Long wall closure See: closure wall-controlled shoots Ore shoots that occur adjacent to certain favorable wall rocks that presumably influenced deposition from the mineralizing fluids. Stokes wall drag The amount of friction resulting from the drill rods rubbing against the walls of a borehole or the inside surface of the casing lining a borehole. Long waller Laborer who builds walls to support backfilling. See: pack builder Fay wall face Scot. The face of the coal wall; the working face. Fay wall friction

3530

a. The drag created in the flow of a liquid or gas because of contact with the wall surfaces of its conductor, such as the inside surfaces of a pipe or drill rod or the annular space between a drill string and the walls of a borehole. Long b. The drag resulting from compaction of loose materials around the outside surfaces of drive pipe, casing, etc. Also called skin friction. Long walling a. The brick or stone lining of shafts. Fay b. Derb. Stacking or setting up ironstone, etc., in heaps, preparatory to being measured or weighed. Fay walling curb See: curb; foundation curb; water ring. walling scaffold See: bricking scaffold walling stage A movable wooden scaffold suspended from a crab on the surface, upon which the workers stand when walling or lining a shaft. Fay walling up The building up of a layer of mud cake or compacted cuttings on the borehole sidewalls; the filling of cracks or caved portions of the borehole walls with cement. Long wall off To seal cracks, crevices, etc., in the wall of a borehole with cement, mud cake, compacted cuttings, or casing. Long wall packing The compaction of sticky cuttings that collect and adhere to the walls of a borehole. Long wallplate a. A horizontal timber supported by posts resting on sills and extending lengthwise on each side of a tunnel. Roof supports rest on wallplates. Syn: pad b. A horizontal member, usually of wood, bolted to a masonry wall to which the frame construction is attached. Also called headplate. ACSG, 1 3531

wallplate anchor A machine-bolt anchor with a head at one end and threaded at the other, and fitted with a plate or punched washer so that when embedded in the masonry it will be securely anchored and will hold a wallplate in place. ACSG, 1 wall rock a. See: country rock b. The rock forming the walls of a borehole. Long c. The rock adjacent to, enclosing, or including a vein, layer, or dissemination of ore minerals. It is commonly altered. The term implies more specific adjacency than host rock or country rock. Syn: walls of a vein d. The rock mass comprising the wall of a fault. AGI wall-rock halo A dispersion pattern formed in the rock adjoining mineral deposits where the chemical composition has been modified by the ore-forming fluids. See: halo wall-rock pattern A channel dispersion pattern in which the minor elements of the walls of the channels have been modified. Wall-rock dispersion patterns of importance usually are those formed at the time the orebodies were being deposited. Lewis walls a. Coal roadways in pillar-and-stall mining. Nelson b. The side of an orebody defining where the ore ceases and the country rock begins. Walls may be definite or indefinite. See also: footwall; hanging wall. Nelson wall saltpeter See: nitrocalcite wallscraper bit A rotary bit used to enlarge the diameter of a borehole. BS, 9 Wallsend Eng. A grade of coal for household purposes: originally from Wallsend, on the Tyne, but now from any part of a large district in and near Newcastle. Standard, 2 walls of a vein 3532

See: wall; wall rock. walpurgite A triclinic mineral, Bi4 O4 (UO2 )(AsO4 ).2H2 O ; radioactive; yellow-orange; associated with troegerite, zeunerite, uransphaerite, torbernite, and uranospinite. Also spelled walpurgin. waltherite A discredited term equal to walpurgite. Am. Mineral., 1 Walton filter An emerald glass or beryloscope mounted to resemble a hand loupe. Observed through it the filament of an incandescent lamp appears reddish yellow, and this color is not changed when also passing through most genuine emeralds; but a Brazilian emerald from Minas Geraes appears green, an epidote red, and a dioptase green. Syn: emerald loupe See also: emerald glass wander a. An unintentional change in the course of a borehole. CF: deviate; walk; warp. Long b. See: band wander wane A defect in a timber or plank. Crispin want A zone in which the coal of a coal seam is missing, owing to a low-angle normal fault or a washout, squeeze, or roll. CF: nip; pinch. Syn: cutout Ward drill A hand drill that can be used in a river on a barge or on a platform built on two large canoes. Basically, it consists of four straight poles, 5 to 7 in (12.7 to 17.8 cm) in diameter at the large end, which are set into notches in planks to prevent their sinking into the ground. The poles are joined at the top by a shaft that holds the pulley for the drill wire or rope. The walking beam is activated by 8 to 10 persons lining up on the crossarm. They pull down to raise the tools and vary their manner of movement, depending on whether they are driving casing, drilling, or pulling casing. The Ward drill is most efficient in shallow ground, but can be used in depths up to 90 ft (27.4 m). Mining 3533

warden a. A term used in south Wales for a strong massive sandstone associated with coal. AGI b. In Australia an officer under the Mining Act with magisterial and executive authority over a goldfield. wardite A tetragonal mineral, NaAl3 (PO4 )2 (OH)4 .2H2 O ; bluish-green; forms oolitic or crystalline encrusting layers; in Cedar Valley and near Fairfield, UT. Ward-Leonard control a. A method of controlling the speed of electric winding or other large direct-current motors, employing a variable voltage generator to supply the motor armature, and driven by a shunt motor. See also: automatic cyclic winding; Ilgner system. Nelson b. In a modification, the Ward-Leonard-Ilgner system incorporates a heavy flywheel on the shaft of the generator, which smooths out surges in the system. Pryor, 3 waringtonite A hydrated sulfate of copper that shows an emerald green color. Syn: brochantite wark Eng. Black slaty stone overlying coal seams, Somerset Coalfields. Also spelled werk. warning lines The lines drawn on working plans to indicate the limit beyond which workings should not extend; e.g., because of the proximity of disused or abandoned workings. BS, 7 warp a. The amount a borehole has wandered off course. CF: wander Long b. A general term for a bed or layer of sediment deposited by water; e.g., an estuarine clay, or the alluvium laid down by a tidal river. See also: warping warped fault A fault, usually a thrust fault, that has been slightly folded. AGI warping

3534

The slight flexing or bending of the Earth's crust on a broad or regional scale, either upward (upwarping) or downward (downwarping); the formation of a warp. AGI warrant a. A general term for the clay floors of coal seams, particularly when hard and tough. See also: underclay b. The document of title to metal stored in an LME registered warehouse. The warrant is a bearer instrument and states the brand of metal, its weight, the number of pieces, and the rent payable. Wolff warrant clay See: underclay warren earth See: fireclay Warren girder A triangulated truss made up only of sloping members between the horizontal top and bottom members with no verticals. See also: N-truss Hammond warrenite a. A general term for gaseous and liquid bitumens consisting mainly of a mixture of paraffins and isoparaffins: a variety of petroleum rich in paraffins. b. A pink cobaltoan variety of smithsonite. c. A discredited name for owyheeite or jamesonite. Warrington Strand construction in which one layer of wires is composed of pairs of large and small wires, thus 6 x 19 (6 and 6/6/1) equal laid. See also: equal lay Warrington rope A wire rope comprising 7 wires of the same size covered by 12 wires alternately large and small. Lewis warwickite An orthorhombic mineral, (Mg,Ti,Fe,Al)2 (BO3 )O ; forms dull, brownish-black prismatic crystals having perfect cleavage. Warwick safety device 3535

A safety appliance placed near the upper end of an inclined haulage road to stop a tram running wild down the incline. It consists of a heavy beam longer than the height of the roadway and is normally held up entirely at roof level, but is hinged at the lower end. In the event of a tram running away from above, a haulage hand can pull a rope that releases the upper end of the beam that drops and stops the tram. Nelson Warwickshire method A method of mining contiguous seams. See also: bord-and-pillar Fay wash a. Loose or eroded surface material (such as gravel, sand, silt) collected, transported, and deposited by running water, such as on the lower slopes of a mountain range; esp. coarse alluvium. Syn: wash stuff AGI b. An alluvial placer. AGI c. In coal mining, a washout. Nelson d. The wet cleaning of coal or ores. Nelson e. Auriferous gravel. Fay f. To clean cuttings or other fragmental rock materials out of a borehole by the jetting and buoyant action of a copious flow of water or a mud-laden liquid. The similar ejection of core or drill spring equipment from a borehole. See also: alluvial cone washability Coal properties determining the amenability of a coal to improvement in quality by mechanical cleaning. BS, 5 washability curve A curve or graph showing the results of a series of float-and-sink tests. A number of these curves are drawn to illustrate different conditions or variables, usually on the same axes, thus presenting the information on one sheet of paper. Washability curves are essential when designing a new coal or mineral washery. There are four main types of washability curves: characteristic ash curve, cumulative float curve, cumulative sink curve, and densimetric or specific gravity curve. Nelson; BS, 5 wash boring a. Drilling by use of jet water applied inside a casing pipe, in unconsolidated ground. Pryor, 3 b. A test hole from which samples are brought up mixed with water. Nichols, 1 wash-boring drill A drill rig utilizing the jet action of a high-pressure stream of water to produce a borehole in soft or unconsolidated material. Long wash bottle 3536

a. A bottle or flask fitted with two glass tubes passing through the stopper, so that on blowing into one tube a stream of water issues from the other tube. The stream may be directed upon anything to be washed or rinsed. Newer wash bottles are made of flexible plastic with a single tube. Hess b. A bottle for washing gases by passing them through liquid contained in it. Hess washbox In coal preparation, the jig box in which feed is stratified and separated into fractions (heavier below and lighter above). A feldspar washbox has a bedding of that mineral. Pryor, 3 washbox air cycle The valve-timing cycle determining the periods of air admission and exhaust. BS, 5 washbox cells The individual portions into which the part of a washbox below the screen plate is divided by transverse division plates, each being capable of separate control. BS, 5 washbox center sill A sill fitted over a center extraction chamber. BS, 5 washbox center weir An adjustable plate situated between the feed end and the discharge end of a washbox and serving to regulate the forward movement of material through the box. BS, 5 washbox compartments The sections into which a washbox is divided by transverse division plates that extend above the screen plate to form a weir; each compartment usually comprises two or more cells. BS, 5 washbox discharge sill That part of the washbox over which the washed coal passes out of the box. Usually the discharge sill is a part of the discharge-end refuse extraction chamber. BS, 5 washbox feed sill That part of the washbox over which the feed passes when it enters the box. Usually the feed sill is a part of the feed-end refuse extraction chamber. BS, 5 3537

washbox screen plate a. The perforated plate or grid that supports the bed of material being treated. BS, 5 b. Also called grid plate; sieve plate; bedplate. washbox slide valve A washbox air valve operated by means of a reciprocating motion. Also called washbox piston valve. BS, 5 wash dirt a. The tailings or material discarded in the operation of washing an alluvial deposit for gold. Nelson b. Gold-bearing earth worth washing. Also called wash stuff; wash gravel. See also: washing stuff washed coal a. Coal from which impurities have been removed by any form of mechanical treatment. BS, 4 b. Coal produced by a wet-cleaning process. BS, 5 washed out Said of a coal seam when the bed thins out. Mason washery a. A place at which ore, coal, or crushed stone is freed from impurities or dust by washing. Also called wet separation plant; washing plant. See also: washing apparatus; wash place; coal-preparation plant; dense-medium washer; efficiency of separation. Webster 3rd b. A coal preparation plant in which a cleaning process is carried out by wet methods. BS, 5 c. A building resembling a breaker used in reclaiming culm and fine coal from old banks. Korson washery effluent Surplus water discharged from a washery, usually to waste (after settlement of solids in suspension). BS, 5 washery products The final products from a washery. BS, 5 washery pump 3538

A pump generally of simple construction and heavy design since slurry presents a difficult pumping problem owing to its erosive action. This type pump is generally of the single-stage type as heads are small, with a solid casing of steel or cast iron about twice the normal thickness to provide against erosive action. Sinclair, 4 washery refuse The refuse removed at preparation plants from newly mined coal. washery water The water used in the wet separation of coal from shale by differences in density. See also: recirculation of water wash gold See: placer gold wash gravel Gravel washed to extract gold. CF: wash dirt washhouse A building on the surface at a mine where the miners can wash before going to their homes. A changehouse. A dryhouse. washing a. That which is retained after being washed; as, a washing of ore. b. The selective sorting, and removal, of fine-grained sediment by water currents. AGI c. Erosion or wearing-away by the action of waves or running water. AGI d. The act or process of cleaning, carrying away, or eroding by the buoyant action of flowing water. Long e. Ore mineral, such as gold dust, that is retained after being washed. washing apparatus a. Machinery and appliances erected on the surface at a coal mine, for extracting, by washing with water, the impurities mixed with the coal dust or small slack. Zern b. Machinery for removing impurities from coals and ores. See also: washery washing drum See: trommel 3539

washing hutch See: hutch washing machine Scot. A machine for separating impurities from coal by means of water. Fay washing plant See: washery washing screen Flat screen or trommel on which passing ore is exposed to sprays or jets of water to remove as undersize any adherent mud or other fine material. Pryor, 3 washing screws Devices in which continuous helical blades arranged about shafts force the material up an inclined trough against a stream of water introduced at the higher end. This action carries away the soluble material occurring with the material and dumps the washed product over the higher end of the trough. Pit and Quarry washing stuff An earthy deposit containing gold that may be extracted by washing. See also: wash dirt washing trommel See: trommel wash metal Molten metal used to wash out a furnace, ladle, or other container. ASM, 1 Washoe canary A miner's slang term for a donkey; burro. Standard, 2 Washoe process The process of treating silver ores by grinding in pans or tubs with the addition of mercury, and sometimes of chemicals, such as blue vitriol and salt. Named from the Washoe District, NV, where it was first used. Webster 3rd 3540

wash ore Crude iron ore containing readily liberated particles of pure iron ore, loosely agglomerated with sands from which they can be separated by scrubbing treatment. See also: natural ore washout a. A channel or channellike feature produced in a sedimentary deposit by the scouring action of flowing water and later filled with the sediment of a younger deposit. Syn: scour and fill b. A channel cut into or through a coal seam at some time during or after the formation of the seam, generally filled with sandstone--or more rarely with shale-similar to that of the roof. See also: cutout; horseback; want; low. Raistrick; AGI c. Barren, thin, or jumbled areas in coal seams in which there is no actual disruption and no vertical displacement of the coal and strata. These disturbances may be divided into three main types; namely (1) classical washouts, (2) pressure belts, and (3) tremor tracts. Authentic washouts should be restricted to the first group. Also called rock fault; nip. See also: roll d. Local thinning or disappearance of a coal seam due to erosion during or shortly after its formation. BS, 11 e. Channellike features that cut or transgress the stratification of the underlying beds; may be small scour-and-fill structures or large erosional channels. Also called cutout. Pettijohn, 1 washout valve Valve in a pipeline or a dam that can be opened occasionally to clear out sediment. Hammond washover a. To wash away or remove material from around the outside of casing pipe, drill stem, junk, or tramp materials in a borehole. See also: washover shoe b. Material deposited by the action of overwash; specif. a small delta built on the landward side of a bar or barrier, separating a lagoon from the open sea, produced by storm waves breaking over low parts of the bar or barrier and depositing sediment in the lagoon. CF: blowover AGI washover shoe A casing shoelike bit used to drill downward around a piece of drilling equipment stuck in a borehole. See also: washover wash pan A pan for washing pay dirt in placer mining. Standard, 2 wash pipe 3541

The pipe that ejects the jet of water through the bit, used in wash boring. Long wash place A place where ores are washed and separated from the waste; usually applied to places where the hand jigs are used. See also: washery Fay wash plain See: alluvial plain washpot In tin-plate manufacturing, a pot containing melted tin into which the plates are dipped to be coated. Webster 3rd wash rod A heavy wall pipe used in lieu of drill rods to conduct water downward inside and to the bottom of a drivepipe being sunk through overburden by a wash-and-drive method. Syn: wash tube wash sale A practice in which promoters, through the connivance of brokers who pretend to carry through transactions and thus obtain false quotations, create a fictitious flurry of activity in the stock market. Hoover wash stuff See: wash; washing stuff. wash table An inclined table used for cleaning coal or ore in which the lighter material or gangue is washed away by water. The coal or ore is fed onto the table and water is allowed to flow down the table carrying away the impurities. wash trommel Rotating horizontal drum that receives ore at one end and water at the other. Ore is tumbled countercurrent to the water so that coarse solids are discharged continuously while water now charged with mud and fine material overflows at the feed end. Pryor, 3 wash tube 3542

See: wash rod wash water Water circulated through the drill string, past the bit, and then out of the borehole between the rods and the walls of the hole while drilling or during washing operations. See also: water wash wasite An altered variety of allanite. Standard, 2 waste a. The part of an ore deposit that is too low in grade to be of economic value at the time of mining, but which may be stored separately for possible treatment later. Lewis b. Refuse and impurities removed in mining and treating coal; also, the coal left in a mine as pillars. c. Gangue. d. Tailings. e. Overburden. f. The refuse from ore dressing and smelting plants. Gob; goaf; old workings; also, the fine coal made in mining and preparing coal for market; culm; coal dirt; also used to signify both the mine waste (such as coal left in pillars) and the breaker waste. g. A working or shaft which has been abandoned and filled with refuse (goaf or gob), or with material from the fall of the hanging wall. Syn: condie h. See: spoil waste blasting On some coal faces, the stone overlying the seam does not always fall in the wastes after withdrawing the supports. To avoid excessive weight on the face, which would cause dangerous roof conditions, it is desirable to blast down the stone in the wastes. Also, in thick seams, the overlying strata requires breaking down to provide sufficient stone for building packs. The holes for waste shots must be drilled from the face side so that the driller is working under a supported roof. Care must be taken to ensure that the holes are not drilled up into the solid strata and that the burden on the shot is not excessive. McAdam, 2 waste drainage The controlled leakage of air through a waste to ensure that large concentrations of mine gases do not accumulate in it. BS, 8 waste dump The area where mine waste or spoil materials are disposed of or piled. waste edge support 3543

A row of rigid timber or steel props or chocks set along the edge of the waste and parallel to the longwall face to induce the roof beds to break and to secure caving of the waste area. See also: breaker props Nelson waste-filled stopes In these methods, support for walls and for workers and machines is furnished by waste rock, tailing sand, etc., called filling or gob. In true waste filling, the orebody is excavated in sections alternating with filling, and it is sometimes referred to as cut-andfill stoping. Higham waste filling Material used for support in heavy ground and in large stopes to prevent failure of rock walls and to minimize or control subsidence and to make it possible to extract pillars of ore left in the earlier stages of mining. Material used for filling includes waste rock sorted in the stopes or mined from rock walls, mill tailing, sand and gravel, smelter slag, and rock from surface open cuts or quarries. Lewis waste-heat boiler A boiler that uses the heat of exit gases from furnaces to produce steam or to heat water. Pryor, 3 wasteman In anthracite and bituminous coal mining, a laborer who looks after and keeps clean the airways, haulageways, or working places of a mine. Also called cleanup man; dirt shoveler; sweeper. See also: jerry man DOT waster a. Tinplate below the standard weight and quality. Standard, 2 b. Spoiled or imperfect casting or machined part that must be discarded although partly processed. Pryor, 3 c. A brick, structural or refractory, that is defective as drawn from the kiln; wasters in the refractories industry are crushed and reused as grog. Dodd waste raise An excavation in a mine in which barren rock and other material is broken up for use as filling at the stope. Stoces waste rock

3544

Barren or submarginal rock or ore that has been mined, but is not of sufficient value to warrant treatment and is therefore removed ahead of the milling processes. Pryor, 4 wastes The unfilled or unpacked portions of workings in a mine. TIME waste water Excess water allowed to run to waste from the water circuit. BS, 5 wasteway a. A channel for carrying off superfluous water. Webster 3rd b. The channel required to convey water discharged into it from a spillway, escape, or sluice; a spillway. Seelye, 1 wasting asset Property (as mines or lumber tracts) subject to depletion. Webster 3rd wastrel Eng. A tract of wasteland, or any waste material. Fay watchmen Weak coal pillars left in workings to give warning of an impending collapse. Briggs water a. Clear, colorless liquid. b. A rarely used term referring to the color and clarity of a precious stone or pearl, and esp. of a diamond. AGI water ampule A fire-resistant plastic container of water that is used as a safety precaution in shotholes. BS, 12 water-ampul stemming A water cartridge for stemming shotholes in coal or rock. The ampul consists of a plastic (polyvinylchloride) bag, 1-1/4 in (3.2 cm) in diameter and 18 in (45.7 cm) in length. When filled with water and the neck of the bag tied off, the filled ampul is about 15 in (38.1 cm) in length and holds slightly over 1/2 pint (0.24 L) of water. Compared with dry clay or sand, the use of water ampuls for stemming effects substantial reductions in 3545

both the airborne dust and the nitrous fumes produced by shot firing. This applies to both coal and rock blasting. Also called a water dummy. Syn: cushion firing water-avid surface A term used to describe a surface that seems to prefer contact with water to contact with air. In flotation, minerals with a water-avid surface will not float, while those with an airavid surface will. The object of reagent additions in flotation is to form a water-repellent surface on the minerals to be floated and a water-avid surface on the minerals that are not to float (hydrophilic). CF: air-avid surface water bailer See: bailer water balance An obsolete water-raising apparatus consisting of a swinging frame carrying a double series of troughs ascending in zigzag lines, and so adjusted to each other that as the frame rocks in either direction water may be passed to a higher level. Standard, 2 water barrel A barrel-shaped hoppit designed to collect and hoist water from the bottom of a sinking shaft. Water barrels are now obsolete. See also: pneumatic water barrel; sinking pump; water kibble. Also called barrel; bailer. Nelson water barrier a. An area of solid material left unworked to protect a mine, or part of a mine, against entry of secondary water. BS, 10 b. See: barrier pillar water-base mud A drill mud in which the solids are suspended in water. Long water blast a. The expulsion of water under pressure, in mine workings, caused by trapped air expanding as the water level is lowered. BS, 10 b. Explosion caused by a sudden inrush of water. Mason c. The discharge of water down a shaft to produce or quicken ventilation. See also: trombe d. A water-actuated ventilating device. CTD water blasting 3546

Pulsed infusion shot firing. Nelson water block a. A sudden stoppage of water-flow past the face of a bit while drilling is in progress. Long b. A hollow box or block of iron through which water is circulated to protect part of a furnace wall. water boss Aust. The owner or holder of water or water rights who sells the same for mining purposes. waterbound A general term indicating that water is the medium used to assist in filling the voids between mineral fragments and to improve compaction. Nelson water box a. A rectangular wooden pipe used in shafts for conveying water between garlands. BS, 10 b. A square, open, wooden tank car used for removing small amounts of water from low places in a mine. Also, a tank car used for sprinkling the roadways to settle the dust. water break A break in the continuity of the water film upon a metal when it is withdrawn from a bath. CF: wetting water cage A special cage running in guides in a special compartment of a shaft with a separate winding engine. water cartridge A waterproof cartridge surrounded by an outer case, the space between being filled with water, which is employed to destroy the flame produced when the shot is fired, thereby lessening the chance of an explosion should gas be present in the place. water chamber A water reservoir in a mine, usually located at the lowest place, commonly near the shaft station. Also called sump. Stoces 3547

water chrysolite Moldavite. See also: tektite water color The apparent color of the surface layers of the sea caused by the reflection of certain components of the visible light spectrum coupled with the effects of dissolved material, concentration of plankton, detritus, or other matter. Color of oceanic water varies from deep blue to yellow and is expressed by number values that are a variation of the Forel scale. Plankton concentrations may cause a temporary appearance of red, green, white, or other colors. See also: Forel scale water content a. Of a bottom sediment, a ratio obtained by multiplying the weight of the water in the sample by 100 and dividing the results by the weight of the dried sample; expressed as a percentage. Hunt b. See: moisture content water core A hollow core through which water circulates in a mold used for cooling the interior of a casting more rapidly than the outside while the metal is solidifying, such as in casting a cannon. Webster 3rd water coupling See: water swivel watercourse a. A natural or artificial channel for the passage of water, as a river, canal, flume, or drainage tunnel. b. A subsurface opening or passage in rocks through which groundwater flows. water creep The movement of water under or around a structure, such as a dam, built on a semipermeable foundation. See also: piping water curb See: garland water cushion 3548

A water load pumped into drill pipe during a drill-stem test to retard fillup and prevent collapse of pipe under sudden pressure changes. Wheeler, R.R. water-cutoff core barrel A core barrel having a device in its head part that closes and stops the flow of drillcirculation liquid when a core block occurs in the inner tube of the core barrel. Long water cycle See: hydrologic cycle water dam A permanent stopping to seal off a large body or feeder of water. It consists usually of a block of concrete between two brick end walls and these are extended well into the surrounding ground. The contact points and all breaks in the strata are sealed by cement injection. The various pipes, pressure gages, etc., may be left through the stopping. Nelson watered Eng. Containing much water--full of springs or feeders; e.g., heavily watered mines, heavily watered measures, etc. waterfinder See: divining rod water flush A system of well boring in which percussive drills are used in connection with water forced down to the bottom of the hole through the drill rods. This water jet makes the tools cut better and washes the detritus up out of the hole. water gage a. An instrument for measuring the difference in pressure produced by a ventilating fan or air current. See also: manometer b. An instrument for measuring the ventilation pressure. One-inch (2.54-cm) water gage is equivalent to a pressure of 62.5/12 = 5.2 psi (35.85 kPa). See also: inclined water gage; total ventilating pressure. Nelson c. A measure of ventilating pressure, expressed in terms of the height of a column of water. BS, 8 d. A device that measures the pressure at which water is discharged by a pump or the volume of water flowing through a pipe or other conductor. Long e. An instrument 3549

used to measure the depth or quantity of water, such as in a steam boiler or water storage tank. Long f. A manometer used with a Pitot tube to indicate air pressure. Pryor, 3 water garland See: garland water gel a. An explosive material containing substantial portions of water, oxidizers, and fuel, plus a cross-linking agent. FR 249 b. An explosive material containing substantial portions of water, oxidizers and fuel, plus a cross-linking agent. Syn: slurry water gin Scot. A gin actuated by a water wheel. water glass A concentrated and viscous solution of sodium silicate or potassium silicate in water. Used as an adhesive, a binder, a protective coating, in waterproofing cement, and in bleaching. Colorless; amorphous; Na2 O.XSiO2 , in which X = 3 to 5; deliquescent. Syn: waterglass; soluble glass; liquid glass. Handbook of Chemistry and Physics, 2 waterglass See: water glass water grade a. An entry inclination that is just sufficient to drain off water. b. A grade determined by keeping the working place nearly parallel to the edge of a pool of water standing upon its floor. Water grade is sometimes incorrectly called water level. CF: water level water groove See: waterway water hauler a. One who collects in a water box (car) water that accumulates in low places--at the mine entrance, along haulageways, or at the working face--bailing it into a car with a bucket or using a small hand pump. Also called waterman; water monkey; water tender. DOT b. A laborer who hauls water cars into a mine to supply water for sprinkling haulage roads and working places. DOT 3550

water hoist A simple method of disposing of mine water using tanks with an engine or a motor on the surface. The machinery can be easily repaired and the plant is in no danger of being flooded. The high cost of this system and the fact that the shaft cannot be used for other purposes while water is being hoisted are important disadvantages. Water is delivered intermittently and at a decreasing rate as the depth of hoisting increases. This method is less economical than pumping but is useful as an emergency measure in reclaiming a flooded mine. See also: drainage water-holding capacity The smallest value to which the water content of a soil can be reduced by gravity drainage. ASCE water inch a. The discharge from a circular sharp-edged orifice 1 in (2.54 cm) in diameter with a head of one line above the top edge that is commonly estimated at 14 pints/min (6.6 L/min), and that constitutes an old unit of hydraulic measure. Webster 3rd b. See: miner's inch water infusion A technique being used abroad to suppress or prevent the formation of dust, in advance of mining a coal seam. Water (or sometimes foam or steam, which is costlier but more effective) is injected into the coal ahead of the face through long drill holes, as many as four to six per face and 6 to 20 m in length. The liquid infuses into the seam along fractures and cracks and, under pressure, penetrates a considerable distance from the hole radially, wetting the coal well. It has proved very effective in reducing dust concentrations during subsequent mining--in some instances, as much as 80%. Water infusion originated in Great Britain (it is used in 25% of the dusty mines) and has been tried experimentally with some success in the United States. See also: pulsed infusion shot firing Hartman, 1 water infusion gun A special tube that acts as a borehole seal in the water infusion process. The tube has two separate passages: one for the infusion water and one for admitting hydraulic fluid, which actuates a piston, expanding the seal in the borehole. The infusion water is supplied by a power pump and the hydraulic fluid is supplied by a hand pump. Syn: infusion gun Nelson water infusion method 3551

A method of removing methane from mines. It consists of injecting water under pressure into a coal seam to push out the gas. Holes are drilled horizontally into the coal face and water is pumped into some of the holes at pressures varying from 200 to 650 psi (1.4 to 4.5 MPa). This forces the methane out through the other holes and also from the exposed part of the coal seam. Syn: methane removal water infusion pump A power pump, mounted on wheels, used to supply high-pressure water for coal seam infusion. It consists of an oil hydraulic circuit that drives two reciprocating rams, which in turn are directly coupled to the two rams of the water pump. Nelson water inrush A heavy and sudden inflow of water into mine workings or shafts. See also: inrush of water water jacket Cast- or wrought-iron sections of a furnace so constructed as to allow free circulation of water for keeping the furnace cool. Also called water block and water box. water-jet drilling The drilling of boreholes in unconsolidated or earthy formations using the erosive power of a small-diameter stream of water forcefully ejected as the cutting tool. See also: jet water kibble A large iron bucket with a valve in the bottom for self-filling; sometimes used in hoisting the water from a mine. See also: water barrel Standard, 2 water level a. A level roadway, constructed with an impervious seal or barrier on the dip side, to divert the flow of water along the level and prevent its seepage to workings on the dip side. The level dips slightly outward to allow gravity flow. See also: drain tunnel b. The level at which, by natural or artificial drainage, water is removed from a mine or mineral deposit. c. A drift at the water level. See also: water grade d. The level of underground waters in a mine, or the elevation to which water will rise in a mine, when the mine is not being drained. Statistical Research Bureau water leyner

3552

A type of rock drill in which water is fed into the drill hole through the hollow drill steel to remove the drill cuttings and, at the same time, allay the dust. Also known as LeynerIngersoll drill. Fay waterlime See: hydraulic limestone water load S. Wales. The head, or pressure per square inch, of a column of water in pumps, etc. water lodge An underground reservoir. CTD waterlogged a. Said of workings or mines that have become filled with water because of abandonment or stoppage of operations. See also: inrush of water Nelson b. Referring to land where the water table is permanently located at or near ground level. See also: water table water loss The amount of drill water that escapes into porous or fractured borehole wall rocks and hence does not return and overflow at the collar of the borehole. Long water machine Scot. A pump or other appliance actuated by a water wheel for raising water. Fay water mains In coal mining, pipes made of cast iron or steel for the conveyance of water. Mason waterman a. A laborer who quenches coke with water so that it may be drawn from the oven, using a sprinkling system of perforated pipes. DOT b. See: water hauler watermelon tourmaline A variety of elbaite in pink, green, and colorless prismatic crystals. water monkey 3553

See: water hauler water of capillarity The water held in the soil above the standing-water level by reason of capillary attraction. Also called held water. See also: capillary water Hammond water of compaction Water furnished by destruction of pore space owing to compaction of sediments. water of constitution Water as an essential component in a mineral or other compound, either as water of crystallization; e.g., CaSO4 .2H2 O gypsum, or water more tightly bound as (OH) groups; e.g., FeO(OH) goethite. Also called H2 O+ in wet chemical analyses. water of crystallization Water that combines with salts when they crystallize and remains as H2 O molecules in the crystal structure; given off upon heating to 100 to 200 degrees C. Also called H2 O in wet chemical analyses. water of hydration Water that is chemically combined in a crystalline substance to form a hydrate, but that may be driven off by heat. AGI water opal a. See: hyalite b. Any transparent precious opal. water packer An expandable device that is placed in a borehole to bar entry of water into the lower part of a hole or to separate two distinct flows of water from different strata. See also: packer water pocket A small, bowl-shaped depression on a bedrock surface, where water may gather; esp. a water hole in the bed of an intermittent stream, formed at the foot of a cliff by the action of falling water when the stream is in the flood stage. AGI waterpower 3554

a. The power of water derived from its gravity or its momentum as applied or applicable to the driving of machinery. Standard, 2 b. A descent or fall in a stream from which motive power may be obtained; specif., in law, the fail in a stream in its natural state, as it passes through a person's land or along the boundaries of it. Standard, 2 water privilege a. The right to the use of the water of a certain stream. Standard, 2 b. The right to the possession and use of a fall of water for mechanical purposes. See also: water right waterproofed stone dust The proofing of stone dust to prevent the particles from caking or becoming sticky in humid atmospheres. Waterproofing is considered essential if stone-dust barriers are to operate effectively at humidities above 85%. Nelson waterproof electric blasting cap A cap specially insulated to ensure reliability of firing when used in wet work. Syn: blasting cap water-quenched Cooled with water, as in hardening steel. Standard, 2 water rate The weight of dry steam consumed by a steam engine for each horsepower per hour. The result is stated in either indicated horsepower or brake horsepower. Brantly, 2 water-repellent surface See: air-avid surface water resistance A qualitative measure of the ability of an explosive or blasting agent to withstand exposure to water without deteriorating or becoming desensitized. water right a. The right to use water for mining, agricultural, or other purposes. See also: water privilege b. The right to appropriate water granted to miners by Federal laws; however, this right applies only to water on public domain. Rights of way are granted over public lands for ditches, canals, flumes, and for the construction of a reservoir to one who has a 3555

right to water. Lewis c. When one has legally acquired a water right, the person has a property right therein that cannot be taken away for public or private use, except by due process of law and upon just compensation being paid therefor. One who has acquired a legal water right can only be deprived of it by the voluntary act of conveying it to another, by abandonment, forfeiture under some stature, or by operation of law. A water right is an independent right and is not a servitude upon some other thing, and is an incorporeal hereditament, being neither tangible nor visible. Ricketts water ring A special form of cast-iron bricking curb whereby space is provided for building up the walling and also a channel or groove for collecting water running down the shaft sides. Rings are built into the shaft lining at intervals and pipes are arranged to conduct the water to the next lower ring or a sump. See also: curb; garland. Syn: walling curb Nelson water-rolled Said of round, smooth sedimentary particles that have been rolled about by water. AGI water sapphire a. A light-colored blue sapphire. b. An intense blue variety of cordierite occurring in water-worn masses in river gravels (such as in Sri Lanka) that may be used as a gemstone. Syn: saphir d'eau c. A term applied to water-worn pebbles of topaz, quartz, and other minerals in Sri Lanka. water seal A water accumulation in a depression in an underground roadway or in a pipe, sufficient to form a seal. BS, 10 water separation See: elutriation water shutoff The sealing off of salt-water-bearing formations to prevent harmful underground water pollution. This is ordinarily done by cementing. Williams water slot A groove incised in the face and outside wall of a noncoring bit that serves as a waterway. Syn: waterway 3556

water smoke To heat a kiln slowly to dry out the moisture from the bricks, before firing. Standard, 2 water softening Removal of excess calcium and magnesium, from water through precipitation of their carbonates (ion exchange) to remove ionized calcium, magnesium, etc. Pryor, 3 water-soluble oils Oils having the property of forming permanent emulsions or almost clear solutions with water. Fay water stemming bags Water-filled plastic bags with a self-sealing valve classified as a permissible stemming device by the U.S. Mine Safety and Health Administration. Atlas waterstone a. A stone whose cutting crystals break away rapidly from its bond. The use of water forms a gritty paste which acts in much the same way as oil when used on an oilstone. The Queer Creek and Hindostan stone are good examples. b. Forest of Dean. A shale, so called in consequence of the wet soil that is found wherever it appears at the surface. c. The formation name for certain flaggy micaceous sandstone and marls in the Keuper of the Midlands. d. Eng. Quarrymen's name for the lowest bed in a Portland stone quarry at Long Crendon, Buckinghamshire. e. A whetstone requiring water instead of oil. water string Casing used to shut off water-bearing formations encountered in the drilling of a well. Williams water swivel A device connecting the water hose to the drill-rod string and designed to permit the drill string to be rotated in the borehole while water is pumped into it to create the circulation needed to cool the bit and remove the cuttings produced. Also called gooseneck; swivel neck; water coupling. CF: air swivel water table The surface between the zone of saturation and the zone of aeration; that surface of a body of unconfined ground water at which the pressure is equal to that of the 3557

atmosphere. Syn: ground-water surface; ground-water table; plane of saturation; saturated surface; level of saturation; phreatic surface; ground-water level; free-water elevation; free-water surface. See also: waterlogged AGI water-table contour A line drawn on a map to represent an imaginary line in the water table of a definite level. These contours are constructed from the data provided by the water-table levels, corrected for differences in surface level at the respective boreholes. A site investigation or opencast plan sometimes show water-table contours. Nelson water-table level Level showing the depth of the water table below the surface; the depth at which water is encountered in trial pits or boreholes. Nelson water-table map A contour map of the upper surface of the saturated zone. Stokes water-table stream Concentrated ground water flow at the water table in a formation or structure of high permeability. watertight a. A borehole in which the conditions are such that no loss of the circulated drill fluid occurs. Long b. A connection, container, or rock strata so tight as to be impermeable to water. Long water-to-cement ratio The ratio between the weight of water and the weight of cement in mortar or concrete. The lower the water-to-cement ratio, the higher will be the strength of the concrete. Hammond water tower a. A standpipe or its equivalent, often of considerable height, giving a head to a system of water distribution. Standard, 2 b. A tower in which a falling spray of water is used to wash gas, etc. Standard, 2 c. A tower containing tanks in which water is stored, built at or near the summit of an area of high ground in cases where the ordinary water pressure would be inadequate for distribution to consumers in the area. CTD 3558

water transport Water is used for transport in some mines, esp. in placers and in claypits, and generally in mines in an elevated position and with a loose mineral. Also filling material is often transported into the mine by water. The mixture of water and solid material can also be conveyed by pumps horizontally or raised to a small height. Stoces water turbine A prime mover coupled to an alternator, using a purely rotary motion to generate an alternating current. The main types of water turbines are (1) the Pelton wheel for high heads, (2) the Francis turbine for low to medium heads, and (3) the Kaplan turbine for a wide range of heads. Hammond water tuyere A water-jacketed tuyere. Webster 3rd water vein a. Groundwater in a crevice or fissure in dense rock. AGI b. A term popularly applied to any body of groundwater, in part because dowsers commonly describe water as occurring in veins. The term is little used among hydrologists. AGI water wash The use of water to remove the soluble constituents of a mill product before further treatment. See also: wash water waterway a. A groove or slot incised in the surface of a bit or other piece of drill-string equipment to provide a channel through which the circulated drilling fluid can flow. Also called watercourse; water groove; water passage; water slot. Long b. A way or channel, either natural (as a river) or artificial (as a canal), for conducting the flow of water. AGI c. A navigable body or stretch of water available for passage; a watercourse. AGI water wheel A wheel so arranged with floats, buckets, etc., that it may be turned by flowing water; used to drive machinery, raise water, etc. The overshot and undershot water wheel, the breast wheel, and the tub wheel are now largely discarded in favor of the turbine. Standard, 2 water witch 3559

A device for determining the presence of water, usually electrically. CF: divining rod water witching See: dowsing waterworn stone Gem minerals, esp. crystals, rounded by action of water rolling them against rocks or gravels in beds of rivers, lakes, or the ocean. water yardage Extra payment to miners who work in a wet place, either by the yard of progress or the ton of coal mined. Fay watt The absolute meter-kilogram-second (mks) unit of power that equals 1 absolute joule per second; the standard in the United States; equals 1/746 hp. Abbrev., w and W. Webster 3rd; Zimmerman wattevillite An orthorhombic or monoclinic mineral, Na2 Ca(SO4 )2 .4H2 O(?) ; forms hairlike crystals. Also spelled wattevilleite. watt-hour A unit of measurement of electrical work that equals 1 W expended for 1 h. Abbrev., whr and wh. Crispin; Zimmerman wattless current An alternative name for the reactive component of an alternating current. CTD wattmeter An instrument for measuring electric power in watts, the unit of electrical energy, volt times amperes; therefore, combining the functions of a volmeter and an ammeter. Abbrev., wm. Crispin; Zimmerman watt-second

3560

A unit of measurement of electrical work that equals the rate of 1 W expended for 1 s. Abbrev., wsec. Crispin Waugh drill See: rock drill wave diffraction See: diffraction wave front In seismology, the surface of equal time elapse from the source point to the position of the resulting outgoing signal at any given time after the source charge has been activated. In a more restricted sense, the surface along which phase is constant at a given instant. AGI wave-front chart In seismology, a diagram of a series of lines showing equal times from the point of detonation. In its construction, velocity information must be known or assumed. Charts are usually constructed so that the horizontal and vertical scales are in length, but they can be constructed so that the horizontal scale is in length and the vertical scale is in time. AGI wave interference The phenomenon that results when waves of the same or nearly the same frequency are superposed, characterized by a spatial or temporal distribution of amplitude of some specified characteristic differing from that of the individual superposed waves. Hy wavelength a. The linear distance between successive wave crests or other equivalent points in a waveform or harmonic series. It is equal to the velocity divided by the frequency-measured in cycles per second--and may be represented by the wave number in reciprocal units, e.g., cm--1 . b. In symmetrical, periodic tectonic fold systems, the distance between adjacent antiformal or synformal axial planes. For asymmetrical and nonperiodic systems, various definitions have been proposed. wavellite

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An orthorhombic mineral, Al3 (PO4 )2 (OH,F)3 .5H2 O ; pearly; forms hemispherical radiating aggregates in low-grade aluminous phosphatic rocks; also occurs in veins; a source of phosphorus. wave meter An instrument to measure and record the wave spectra. Hy wave period The time interval between the appearance of two consecutive wave repetitions at a given point, usually expressed in seconds. The wave segments considered must be the same; i.e., the crests, troughs, etc. Hy wave propagation Radiation, such as from an antenna of r-f energy into space or of sound energy into a conducting medium. Hy wave refraction a. The process by which a water wave, moving in shallow water as it approaches the shore at an angle, tends to be turned from its original direction. The part of the wave advancing in shallower water moves more slowly than the part still advancing in deeper water, causing the wave crests to bend toward parallel alignment with the shoreline. AGI b. The bending of wave crests by currents. AGI wave spectrum A concept used to describe the distribution of energy among waves of different period. Wave speed increases with wave length, so distant storms may be detected by the increase of energy in long period waves. Sea is fully developed when all possible wave frequencies possess energies appropriate to the spectrum for the prevailing wind speed. Hy wave velocity A quantity that specifies the speed with which a wave travels through a medium. Hy wavy extinction See: undulatory extinction wavy vein 3562

A vein that alternately enlarges or pinches at short intervals. Fay wax a. A solid, noncrystalline hydrocarbon of mineral origin, such as ozocerite and paraffin; composed of the fatty acid esters of the higher hydrocarbons. b. Soft or puddled clay used for dams or stoppings in a mine. wax opal An early name for yellow opal with a waxy luster. Fay wax stone Crude ozokerite associated with earthy matter. Tomkeieff wax wall A wall of clay built around the gob or goaf to prevent the entry of air or egress of gas. CTD wax walling The building of clay lumps as a lining to the pack to reduce leakage. If about 15% to 20% of calcium chloride is added to the clay, it will remain plastic. Sinclair, 1 way The rails, sleepers, etc., upon which cars, tubs, or corves run. Fay wayboard a. Eng. A thin layer or band that separates or defines the boundaries of thicker strata; e.g., thick beds of limestone separated by wayboards of slaty shale, sandstone separated by wayboards of clay. Also spelled weighboard. Fay b. Leic. Beds of green marl among sandy shales in the Trias. Arkell waygate The tailrace of a mill. Fay waylandite A trigonal mineral, (B,Ca)Al3 (PO4 ,SiO4 )2 (OH)6 ; crandallite group; white; in Uganda. 3563

way shaft See: winze weak ground Roof and walls of underground excavations that are in danger of collapse unless suitably supported. Pryor, 3 wearing strip A strip of metal applied to any particular device to take the wear of moving parts or objects. In conveyor work, it refers to the strip that is sometimes applied to the chain conveyor troughs and on which the drag chain rides. Jones, 1 wear plate Sections of hardened steel plates of various thicknesses (as desired) which are welded (or bolted) in areas of severe wear, such as the insides of feeders, crushers, transfer chutes, or any other area where mined material passes, creating abrasion, and threatens wearing of these areas. wear rib Hard metal ridge applied to the outside surface of bottom-hole equipment and built up as close as practicable to the set-outside-diameter size of a reaming shell, which serves as a wear pad. Long weather a. To undergo changes, such as discoloration, softening, crumbling, or pitting of rock surfaces; brought about by exposure to the atmosphere and its agents. AGI b. To undergo or endure the action of the elements; to wear away, disintegrate, discolor, or deteriorate under atmospheric influences. Webster 3rd weather door A door in a mine level whose purpose it is to regulate ventilation currents. A trapdoor. Fay weathered layer a. In seismic work, a zone extending from the surface to a limited depth, usually characterized by a low velocity of transmission, which abruptly changes to a higher velocity in the underlying bedrock. The name is erroneous, and the zone is more 3564

properly called the low-velocity layer. AGI b. In seismology, the zone of the Earth that is immediately below the surface, characterized by low seismic-wave velocities. AGI weathered rock Rock, the character of which has been changed by exposure to decaying conditions found in the zone of weathering. Long weathering a. The destructive processes by which earthy and rocky materials on exposure to atmospheric agents at or near the Earth's surface are changed in color, texture, composition, firmness, or form, with little or no transport of the loosened or altered material; specif. the physical disintegration and chemical decomposition of rock that produce an in-situ mantle of waste and prepare sediments for transportation. Most weathering occurs at the surface, but it may take place at considerable depths, as in well-jointed rocks that permit easy penetration of atmospheric oxygen and circulating surface waters. AGI b. Exposing ore to the atmosphere for long periods in order that a part, at least of the sulfide content, may become oxidized and washed away by the rain. Osborne c. See: seasoning weathering correction In seismic exploration, a correction applied to reflection and refraction data for variations in travel time produced by irregularities in a low-velocity or weathered layer near the surface. Syn: low-velocity-layer correction weathering index A measure of the weathering characteristics of coal, according to a standard laboratory procedure. Syn: slacking index weathering map In seismic work, a map on which the low-velocity layer, or weathered layer, is plotted and contoured to show areal variations. AGI weathering of coal The slow disintegration of coal into fires in surface stockpiles under the action of the weather, particularly frost after a wet period. See also: spontaneous combustion weathering of roadways

3565

The disintegration or scaling of exposed surfaces of mine roadways, particularly in the case of clay or shale rocks. Gunite has been used for roadway protection against weathering. See also: guniting Nelson weathering shot In seismic exploration, the detonation of a small explosive charge in the weathering or low-velocity layer to determine its velocity characteristics and thickness. AGI web The slice or thickness of coal taken by a cutter loader when cutting along the face. The thickness of a web varies from a few inches with plow-type machines to up to about 6 ft (1.8 m) with the A.B. Meco-Moore. The term web tends to be restricted to thin or medium slices of coal. See also: buttock weber Magnetic flux equivalent in the meter-kilogram-second (mks) system of the maxwell in the centimeter-gram-second (cgs) system. One weber equals 10 8 maxwells. Abbrev., wb. Pryor, 3 weberite An orthorhombic mineral, Na2 MgAlF7 ; pale gray; forms grains in cryolite; in Greenland. Weber process A method of manufacturing pig iron in which the ore is mixed with a proportionate amount of coal sufficient to smelt it; after adding a binder the mixture is briquetted by means of a roller press into ovoids, which are subjected to low temperature carbonization between 550 degrees C and 600 degrees C, followed by smelting in a low shaft furnace. Osborne weddellite A tetragonal mineral, Ca(C2 O4 ).2H2 O ; in mud at the bottom of the Weddell Sea, Antarctica; also as urinary calculi. CF: whewellite wedge a. A wedge-shaped piece of wood used to tighten timber sets against the roof and sides. See also: lag; lid. Nelson b. A tapered piece of material used to initiate the deflection of a borehole. See also: deflecting wedge; Hall-Rowe wedge. Long c. Tapered piece of core 3566

that tends to bind and block a core barrel. Long d. A piece of mica that, on splitting, yields pieces thicker at one end than at the other. Skow e. The shape of a stratum, vein, or intrusive body that thins out; specif. a wedge-shaped sedimentary body, or prism. See also: prism wedge-and-sleeve bolt A bolt designed for use in roof bolting. It consists of a rod 1-3/4 in (4.45 cm) in diameter with one end threaded and the other end shaped to form a solid wedge. A loose split sleeve with an outside diameter of 1-1/2 in (3.81 cm) is fitted over the wedge. Anchorage is provided when the bolt is pulled downward in a hole and the sleeve is held by a thrust tube. Split by the wedge head of the bolt, the sleeve expands until it grips the sides of the hole. See also: bolt; slot-and-wedge bolt. Nelson wedge bit A tapered-nose noncoring bit, used to ream out a borehole alongside a steel deflecting wedge in hole-deflection operations. Also called: bullnose bit; wedge reaming bit. Syn: wedging bit wedge capping A winding rope capping consisting of two tapered iron wedges that encircle the rope, the end of which is prevented from unravelling by casting onto it a small block of white metal. The wedges are contained by a steel bow, over which four or five wrought-iron hoops are driven. The greater the pull on the rope, the more the wedges grip it as they are drawn into the encircling hoops. Mason wedge clinometer An end clinometer the bottom end of which is shaped to match the wedge-guide pin on the drive wedge; hence the two can be fastened together with copper shear rivets. When a drive wedge is driven into a wooden plug in a borehole the copper rivets break; after the clinometer has been removed from the borehole, the relation of the bearing and inclination readings to the flat face of the projection on the bottom of the clinometer case can be used to orient and place the deflection wedge in a manner so as to direct the deflected hole to follow the desired course. CF: plain clinometer; line clinometer. Long wedge core lifter A core-gripping device consisting of a series of three or more serrated-face, tapered wedges contained in slotted and tapered recesses cut into the inner surface of a lifter case or sleeve. The case is threaded to the inner tube of a core barrel. As the core enters the inner tube, it lifts the wedges up along the case taper. When the barrel is raised, the wedges are pulled tight, gripping the core. Long 3567

wedge cut a. A cut in which the central holes are positioned to cause the breakout of a wedgeshaped section of strata when fired. BS, 12 b. A drill-hole pattern with the cut holes converging to form a V or wedge. The other holes are drilled to break to the opening made by the cut holes. See also: V-cut c. A type of geometry for blasting pattern often used in drifting work. It can be adopted for all strata conditions. A wedge cut consists of pairs of holes, usually drilled horizontally, that meet or finish close together at the back of the cut so that a wedge-shaped section of the rock face will be removed on blasting. The holes should be drilled at an angle of approx. 60 degrees to the face line. Accordingly, the depth of pull that can be obtained with this type of cut is governed by the width of the drift, as this determines the maximum length of drill steel that can be used. Typically, the pull ranges from 5 ft (1.5 m) in a 12-ft-wide (3.7-m-wide) drift up to 6-1/2 ft (1.8 m) in a 15-ft-wide (4.6-m-wide) drift. McAdam, 2 wedge guide One of several implements used collectively to arrest a cage or skip in the event of an overwind using a multirope friction winder. Frictional forces, which gradually increase by virtue of the wedging action of the guides, are relied upon to bring the cage to rest and hold it in a stationary position with the aid of jack catches. See also: detaching hook wedge off To deviate or change the course of a borehole by using a deflecting wedge. See also: bypass wedge-out The edge or line of pinch-out of a lensing or truncated rock formation. AGI wedge out See: thin out wedge pilot That part of the bottom end of a Hall-Rowe deflecting wedge that matches the guide pin on the upper end of the Hall-Rowe drive wedge and by means of which the deflecting wedge can be oriented to direct the deflected borehole in the intended direction. Long wedge reaming bit A tapered or bullnose rotary bit used to restart drilling after a deflection wedge has been fitted into a borehole. See also: wedging reamer; wedge bit. BS, 9 3568

wedge roaster Multiple-hearth vertical furnace. Rabbles rotating on each circular horizontal hearth work the continuously fed material across alternately to the periphery and then, on the next hearth below, toward the center, so that it gravitates through either a central or a peripheral opening and is at the same time exposed to rising heat or air blown through rabble arms. Pryor, 3 wedge rock An expression used on the Comstock lode to designate rock better than waste but too poor to be classed as "pay ore" or even "second-class ore." It became a custom to throw a wooden wedge onto a car containing very low grade ore, hence the term wedge rock. Syn: pin wedge rose bit A serrated-face, hardened-metal, noncoring, cone-shaped bit used primarily to mill off part of the stabilizing or rose ring on the top end of a Hall-Rowe deflecting wedge. Long wedge-set A diamond bit with wedge-shaped configurations in the crown that are inset with diamonds. wedge shot See: wedge cut wedge socket fitting A wire rope attachment in which the rope lies in a too-small groove between a wedge and housing, so that pull on the rope tightens the wedge. Nichols, 1 wedge theory The analysis formulated by Coulomb in 1776 of the force tending to overturn a retaining wall. Its basis is the weight of the wedge of earth that will slide forward if the wall fails. Hammond wedge-wire deck A screen deck comprising wires of wedge-shaped cross section spaced from each other at a fixed dimension; the underflow thus passes through an aperture of increasing cross section. Also called wedge-wire sieve (undesirable usage). BS, 5 3569

wedge-wire screen A screen designed to reduce or eliminate clogging of material. It consists of wedgeshaped parallel wires with their wide edge upward. This type of screen is used for dewatering coal on vibrating, shaking, or stationary screens. Nelson wedging a. A method used in quarrying to obtain large, regular blocks of building stone, such as syenite, granite, marble, and sandstone. In this method, a row of holes is drilled, either by hand or by pneumatic drill, close to each other to create a longitudinal crevice. A gently sloping steel wedge is driven into this crevice. Usually several wedges are driven, and the block of stone can be detached without shattering. Stoces b. The act of changing the course of a borehole by using a deflecting wedge. Syn: whipstocking c. The lodging of two or more wedge-shaped pieces of core inside a core barrel and therefore blocking it. Long d. The material, moss, or wood used to render a shaft lining tight. Fay e. The splitting, breaking, or forcing apart of a rock as if by a wedge, such as by the growth of salt or mineral crystal in interstices; specif. frost wedging. AGI wedging and blocking See: blocking and wedging wedging bit See: wedge bit wedging crib In a circular mine shaft, a steel ring made of segments wedged securely to rock walls for use as a foundation for masonry lining. Also called: wedging ring; wedging curb. Pryor, 3 wedging curb See: curb wedging down Breaking down coal at the face with hammers and wedges instead of by blasting. Fay wedging reamer A reaming bit used to ream down alongside and pass the deflection wedge when deviating a borehole. Also called wedge bit; wedge reaming bit. Long 3570

wedging shot An opening shot. A center cut. Fay weeksite An orthorhombic mineral, K2 (UO2 )2 Si6 O15 .4H2 O ; resembles uranophane; in the Thomas range, Juab County, UT. Syn: gastunite weeks manometer An inclined water gage. Nelson weeper A small feeder of water. BS, 10 weeping rock A porous rock from which water oozes. Weg rescue apparatus Oxygen supply fed automatically to a rescue worker through a valve controlled by the worker's breathing action, forming part of a portable outfit. Pryor, 3 wegscheiderite A triclinic mineral, Na5 (CO3 )(HCO3 )3 ; forms fibrous aggregates of tiny acicular to bladed crystals; Green River formation, WY. wehrlite a. A mixture of pilsenite and hessite. b. A peridotite composed chiefly of olivine and clinopyroxene with accessory opaque oxides common. weibullite An orthorhombic mineral, Pb6 Bi8 (S,Se)18 (?) ; differs from galenobismutite in possessing two distinct cleavages; steel-gray. Weichbraunkohlen-dopplerit See: dopplerite 3571

weigh batcher Batching plant in which all ingredients for a concrete mix are measured by weight. Hammond weigher-and-crusher man Person who weighs zinc ore and other materials to be sintered, and crushes sintered ore preparatory to further reduction. DOT weighing feeder A device that handles the feed continuously over a belt that is balanced to weigh a stream of ore. Pit and Quarry weighing-in-motion system An electronic system which weighs individually loaded coal wagons as they roll over a rail scale, feeding the information into a totalizing printer, which automatically prints out gross and net weights. It employs hermetically sealed load cells which accurately convert physical weight into electrical impulses. See also: weightometer Syn: electronic weighing weigh larry A traveling hopper for receiving, weighing or measuring, and distributing bulk materials. Usually fitted with a scale, either manually operated or of the automatic recording type. Weigh larries may be suspended between overhead tracks or carried on rails mounted below them. They may be hand-pushed or power-propelled, and some designs provide a riding platform or cab for the operator. A remote-control device for operating the bunker or bin gates is usually mounted on the larry chassis. weight a. Roof movement, esp. when it can be seen or heard. Mason b. Fracturing and lowering of the roof strata at the face as a result of mining operations. See also: crush weight batching Weighing and combining the correct proportion of cement and aggregate in a concrete mix. Nelson weight break

3572

Cracks developing from the upper or tension side of a stratum caused by bending moment over a coal seam. Such breaks are induced in the nether roof in consequence of the moment exercised by the weight of the roof-stratum overhanging the face, cantilever fashion. The weight break differs from a shear plane in the more ragged and uneven character of the fracture and in hanging over the waste instead of over the unmined coal seam. Also called first break. Briggs weight dropping A seismic technique by which energy can be sent downward into the ground without the necessity of drilling shotholes. This technique involves lifting a weight, then permitting it to fall and strike the ground. The waves from the impact are then recorded. In areas where drilling is difficult, otherwise undesirable, or unduly expensive, this technique may be highly advantageous. Dobrin weighted average Value calculated from a number of samples, each of which has been assigned an importance in accord with its position and general trustworthiness. In this connection a sample which was cross-checked by others would be more reliable than one which was isolated, particularly if the latter showed abnormal values or was for any other reason suspect. The cross-checked sample is sometimes called a weighted sample in mineral valuation of a deposit. Pryor, 3 weighted average depth A method of comparing the average depth of mine workings. It is based on the average depth from which the output is obtained, weighted for the tonnage produced. Nelson weighted flowsheet A materials flowsheet including a statement of the capacity in tons per hour at principal points in the plant. BS, 5 weight indicator An apparatus for recording and indicating the tension on a drilling line of a diamond or rotary drill. See also: tension drilling weighting The occurrence of fracturing of the upper roof, with consequent rapid increase of the weight carried on the timber and packs supporting the roof; distinct from the fracturing of the nether roof. TIME 3573

weightometer An appliance for the continuous weighing of coal or other material in transit on a belt conveyor. See also: weighing-in-motion system Nelson weight pit The pit below the shaft station where heavy weights are attached to the guide ropes to keep them taut. Roughly, the weight needed is 1 st for each 1,000 ft (1.97 t per 1,000 m) of rope. Higham weight strength The strength of an explosive per unit weight, expressed as a percentage of the value for blasting gelatin as a standard. See also: absolute weight strength Weinig flotation cell Square type of machine in which air is blown down to join pulp entering the cell below a mechanically driven impeller. Pryor, 3 weir a. A small dam in a stream, designed to raise the water level or to divert its flow through a desired channel. AGI b. A notch in a levee, dam, embankment, or other barrier across or bordering a stream, through which the flow of water is regulated. AGI weir head The depth of water in a measuring weir as measured from the bottom of the notch to the surface of the water upstream of the weir. The velocity of approach is not included. Hammond weir table A device to estimate the quantity of water that flows during a given time over a weir of a given width at different heights of water. Fay Weisbach triangle a. A configuration used in the surveying of a mine shaft. Pryor, 3 b. The highly attenuated triangle formed by the plan position of two shaft plumblines and one observation station. BS, 7 weissite 3574

An isometric(?) mineral, Cu5 Te3 ; bluish-black; at Vulcan, CO. weiss quadrilateral The quadrilateral formed by the plane position of two shaft plumblines and two observation stations. BS, 7 welded dike A term applied to pegmatitic and aplitic dikes, the boundaries of which have been obliterated by continued growth of the minerals of the granite into which the dikes have been injected. Holmes, 2 welded tuff A glass-rich pyroclastic rock that has been indurated by the welding together of its glass shards under the combined action of the heat retained by particles, the weight of overlying material, and hot gases. It is generally composed of silicic pyroclasts and appears banded or streaky. Syn: tuff lava weldment A base or frame made of pieces welded together, as contrasted with a one-piece casting or a bolted or riveted assembly. Nichols, 1 Weldon mud See: Weldon process Weldon process A process used formerly for the recovery of manganese dioxide in making chlorine from hydrochloric acid in a stoneware still, by adding lime to the still liquor and oxidizing with air to precipitate a mud containing calcium manganite and yielding chlorine when recirculated and treated with hydrochloric acid. Webster 3rd well a. A borehole or shaft sunk into the ground for the following purposes: obtaining water, oil, gas, or mineral solutions from an underground source; introducing water, gas, or chemical reagent solutions under pressure into an underground formation; or removing the leachate from such an operation. See also: borehole mining b. A slot in the front of a hydraulic dredge hull in which the digging ladder pivots. Nichols, 1 c. A hollow cylinder of reinforced concrete, steel, timber, or masonry built in a hole as a support for a bridge or building. Webster 3rd d. Commonly used as a syn. for borehole or drill hole, 3575

esp. by individuals associated with the petroleum-drilling industry. Long e. A wall around a tree trunk that protects it from fill. Nichols, 1 f. An artificial excavation (pit, hole, tunnel), generally cylindrical in form and commonly walled in, sunk (drilled, dug, driven, bored, or jetted) into the ground to such a depth as to penetrate water-yielding rock or soil and to allow the water to flow or to be pumped to the surface; a water well, originally applied to natural springs or pools, esp. mineral spas. See also: artesian well; deep well. g. The crucible of a furnace or a cavity in the lower part of some furnaces to receive falling metal. h. The small dark nonreflecting area in the center of a fashioned stone, esp. in a colorless diamond cut too thick. i. A vertical opening through the hull of a ship in which drill pipe or mining machinery is lowered to the seafloor, rather than being lowered over the side of the ship. Also called: moonpool. well-conditioned triangle A triangle that is equilateral or nearly so. In such a triangle any error in the measurement of an angle will be reduced to a minimum. Hammond well core A sample of rock penetrated in a well or other borehole obtained by use of a hollow bit that cuts a circular channel around a central column or core. AGI well cuttings Rock chips cut by a bit in the process of well drilling and removed from the hole by pumping or bailing. Well cuttings collected at closely spaced intervals provide a record of the strata penetrated. AGI well-drill hole Hole drilled by means of an apparatus known as a well drill, or similar to that, and used in groups for blasting on a comparatively large scale. Such holes are usually 5 in or 6 in (12.7 cm or 15.2 cm) in diameter and from 30 to 150 ft (9.1 to 45.7 m) deep. wellglass fitting A transparent lighting device used as a main lighting device in mines. Its distribution characteristics are simple, since there is no control of light other than that provided by the interior of the upper part of the fitting, which absorbs a large proportion of the upward flux component from the lamp and reflects the remainder. It is usually to be found spaced at intervals of 20 to 50 ft (6.1 to 15.2 m), 6 to 7 ft (1.83 to 2.13 m) high, along the centerline of roads 12 to 14 ft (3.66 to 4.27 m) wide. In general, the most noticeable effect of such a layout is glare. Roberts, 2 wellhole 3576

a. A large-diameter (about 6 in or 15 cm) vertical hole used in quarries and opencast pits for heavy explosive charges. Nelson b. Change room. Hess wellhole blast A method of quarry blasting in which the explosive charges are placed in rows of vertical holes. The loading ratio varies from about 3 st of rock per pound (6 t/kg) of explosive up to about 7 st (14 t/kg) under favorable conditions. Deck loading is usually employed, and a powerful gelatinous explosive is loaded at the bottom of the holes. Nelson wellhole blasting This type of blasting is virtually benching on a large scale. The depth and burden of the holes are much greater, and in consequence, the hole diameter must also be increased to ensure sufficient concentration of the explosive charge. Wellhole blasting is used in limestones esp. if the beds are horizontal and well-defined. It is not often used in highly abrasive igneous rocks because of the cost of drilling. Fraenkel Wellington formula The Engineering News formula for calculating the load-bearing capacity of driven piles. Hammond well log A graphic record of the measured or computed physical characteristics of the rock section encountered in a well, plotted as a continuous function of depth. Measurements are made by a sonde as it is withdrawn from the borehole by a wire line. Several measurements are usually made simultaneously, and the resulting curves are displayed side by side on a common depth scale. Both the full display and the individual curves are called logs. Well logs are commonly referred to by generic type, such as resistivity log and radioactivity log, or by specific curve type, such as sonic log and gamma-ray log. See also: borehole log; sample log; driller's log. Syn: borehole survey; geophysical log; wire-line log. AGI well logging a. A widely used geophysical technique that involves probing of the Earth with instruments lowered into boreholes, their readings being recorded at the surface. Among rock properties currently being logged are electrical resistivity, self-potential, gamma-ray generation (both natural and in response to neutron bombardment), density, magnetic susceptibility, and acoustic velocity. Dobrin b. In deep bores, measurement of resistivity of the formations drilled through. Electrodes are plunged into the drilling mud at controlled spacings. See also: electric log c. The lowering of sensors into a borehole and 3577

recording of physical information as a function of depth. Numerous types of geophysical logs can be recorded, the more common being rate of penetration, temperature, gammaray, electric, and caliper (for hole diameter). Nelson well point A hollow vertical tube, rod, or pipe terminating in a perforated pointed shoe and fitted with a fine-mesh wire screen; connected with others in parallel to a drainage pump; driven into or beside an excavation to remove underground water, to lower the water level and thereby minimize flooding during construction, or to improve stability. AGI well-point pump A centrifugal pump that can handle considerable quantities of air; used for removing underground water to dry up an excavation. Nichols, 1 well seismometer Special type of seismometer that is used when recording in a borehole. Schieferdecker well shooting In seismic work, a method or methods of logging a well so that average velocities, continuous velocities, or interval velocities are obtained by lowering geophones into the hole. Shots are usually fired from surface shot holes, but may be fired in the well itself, or perforating-gun detonations may be used. In continuous logging, a sound source is lowered in the hole together with recording geophones. AGI well-sorted As used by geologists, it applies to material composed of grains of approx. uniform size. As used by engineers, it applies to material containing approx. equal amounts of several grain sizes. Stokes well tube A tube or tubing used to line wells. Standard, 2 well-tube filter A strainer on a driven well tube to keep out grit. Standard, 2 well-tube point A point at the end of a perforated tube used for sinking wells. Standard, 2 3578

well-velocity survey Method of determining the velocity distribution by recording in a borehole. Schieferdecker Welshman A heavy steel ring, about 3 in or 4 in (7.6 cm or 10.2 cm) inside diameter, used in withdrawing a bar stuck or frozen in a skull or iron. The ring is placed on the bar, a wedge inserted, and the bar backed out by sledging on the wedge. Fay Welsh notch A form of joint between the tubing used to line a collar (or a crossbar) and the arms (or uprights) of a timber set; developed in the Welsh coal mines. A Welsh notch is designed to be equally effective in resisting side and roof pressure. Nelson wem See: whim wenkite A hexagonal mineral, Ba4 Ca6 (Si, Al)20 O39 )(OH)2 (SO4 )3 .nH2 O (?) ; cancrinite group. Wentworth grade scale An extended version of the Udden grade scale, adopted by Chester K. Wentworth (18911969), U.S. geologist, who modified the size limits for the common grade terms but retained the geometric interval or constant ratio of 1/2. The scale ranges from clay particles (diameter less than 1/256 mm) to boulders (diameter greater than 256 mm). It is the grade scale generally used by North American sedimentologists. See also: Udden grade scale; phi grade scale; grade scale. AGI Wentworth scale A logarithmic grade scale for size classification of sediment particles, starting at 1 mm and using the ratio 1/2 in one direction (and 2 in the other), providing diameter limits to the size classes of 1,-1/2,-1/4, etc., and 1, 2, 4, etc. Syn: grade scale AGI Wenzel's law Applies to the dissolution of a solid in a liquid. The rate of dissolution is proportional to the surface area of the solid exposed to the action of the solvent. Newton, 1 3579

wernerian Of or relating to Abraham G. Werner (1749-1817), German mineralogist and geologist, who classified minerals according to their external characteristics, advocated the theory of neptunism, and postulated a worldwide age sequence of rocks based on their lithology. Also, said of one who is a great, but dogmatic, teacher of geology. n. An adherent of wernerian beliefs; a neptunist. wernerite A common scapolite. A mineral of the scapolite group, intermediate in composition between meionite and marialite. Syn: scapolite Wesco coal powder Nongelatinous permissible explosive; used in coal mines. Bennett weslienite See: romeite Westfalia pillar plow A plow designed for the extraction of coal pillars and for short, rapidly advancing development faces. The plow is guided along a panzer conveyor, but the pulling forces are not transmitted to the conveyor structure. The plow is automatically advanced at each end of its short run, giving a rapid face advance. This requires the use of self-advancing supports in conjunction with hydraulic anchorages. Nelson Westfalia plow See: hard-coal plow Westfalia tandem plow A plow designed for use in a seam with sticky coal. It consists essentially of two shortened plow bases connected by a heavy tension spring and carrying two adjustable booms fitted with cutting bits and connected at the apex to a cutterhead, which plows at roof level or at any lower level that will bring down the top coal. Nelson westfalite A blasting explosive composed of ammonium nitrate and resin. Webster 2nd Weston photronic cell 3580

This consists of a small box containing an iron disk thinly coated with the rare element selenium. When electromagnetic radiation in the form of light waves falls on this surface it sets up a potential difference between the iron and the selenium, which in turn causes a minute electric current to flow through the sensitive microammeter connected between them. The magnitude of this current is proportional to the intensity of the light, and it can be used as a measure. For use with miners' hand lamps the cell is mounted in a box, the microammeter being housed in the top or side. The lamp to be tested is placed in the box on a turntable, and the candlepower is read off directly since the instrument is already calibrated. Standard, 2 Westphal balance In mineral analysis, a balance used to determine the specific gravity of heavy liquids which are in turn used to determine the specific gravity of mineral grains by a sink-float method. It is a modification of a Walker steelyard (beam) balance. Also called: Mohr balance. CF: Jolly balance; Walker balance. West's solution A liquid consisting of eight parts of white phosphorous and eight parts of sulfur to one part of methylene iodide. Useful in obtaining the refractive index by the Becke method. Refractive index, 2.05. weta material A refractory suitable instead of porcelain and quartz glass. Powdered silicon carbide mixed with silicates and certain metals; resists acids, alkalis, and temperature shock; is not easily broken. wet analysis A method of estimating the effective diameters of particles smaller than 0.06 mm by mixing a sample in a measured volume of water and checking its density at intervals with a sensitive hydrometer. A test may take several days. Nelson wet- and dry-bulb thermometer See: hygrometer; wet-bulb thermometer. wet-and-dry screening In sizing analysis of fine material, preliminary screening by washing a weighed sample on a 200-mesh screen, perhaps with use of a dispersing agent, such as sodium silicate. Removal of the minus fraction (which is settled and later brought into account) is 3581

followed by drying of the on-size and by standard sizing analysis. Screen action is thus rendered more efficient. Pryor, 3 wet assay Any type of assay procedure that involves liquid, generally aqueous, as a means of separation. CF: dry assay AGI wet blasting Shot firing in wet holes. Special explosives are available for wet conditions, and the detonator wires must be well insulated to prevent short-circuiting and misfires. Nelson wet-bulb temperature a. The temperature of the air as measured by a wet-bulb thermometer; it is lower than the dry-bulb temperature (for all cases except when the air is saturated)--ininversely proportion to the humidity. Strock, 2 b. The lowest temperature which can be produced in a given air by the evaporation of moisture into that air. Spalding c. Temperature at which water evaporating into air can bring the air to saturation adiabatically at that temperature--a measure of the evaporating capacity of air. Indicated by a thermometer with a wetted wick. Measured in degrees C. Hartman, 2 wet-bulb thermometer An instrument that measures the evaporating capacity of air. Lewis wet cleaning A coal-cleaning method that involves the use of washers plus the equipment necessary to dewater and heat-dry the coal. This method is generally used when cleaning the coarser sizes of coal. It is a more expensive method than air cleaning and creates the additional problem of water pollution. Coal can, however, be cleaned more accurately by this method than by air cleaning. See also: froth flotation; washery. Kentucky wet clutch A clutch that operates in an oil bath. Nichols, 1 wet criticality Reactor criticality achieved with a coolant. Lyman wet cutting 3582

A method of dust prevention in which water is delivered onto a moving cutter chain, through water pipes, and is carried into the cut where it is intimately mixed with the cuttings. This method is successful in seams up to 4 ft (1.22 m) thick. Mason wet cyclone See: cyclone wet drilling In rock drilling for blasting purposes, injection of water through a hollow drill shank to the bottom of a hole, to allay dust and danger of pneumoconiosis. wet gold-silver ore Lead ore with high silver content. During smelting, the lead trickles through the mass and collects gold and/or silver, which are later recovered. Nelson wet grinding a. Any milling operation carried on in water or a liquid. Enam. Dict. b. The practice of applying a coolant to the work and the wheel to facilitate the grinding process. ACSG, 2 c. Comminution of ore in aqueous suspension; typically practiced in the ball milling of finely crushed rock. See also: grinding Pryor, 3 Wetherill's furnace A furnace with a perforated iron bottom, under which a blast is introduced, and upon which zinc ore (red oxide) is reduced. A muffle furnace for roasting zinc ores. Fay Wetherill's magnetic separator An apparatus for separating magnetic minerals from nonmagnetic minerals. It consists of two flat belts, the upper of which is the wider, run parallel to each other and over long magnets set obliquely to the belts. Consequently, magnetic particles are drawn up against the upper belt, and as they pass beyond the influence of the magnets, fall from the edge past the other belt into a bin. Another form operates by belts moving across the line of travel of the main belt. Liddell Wetherill vacuum casting process In this process, a mold, arranged for bottom feeding, is placed inside a vacuum bell; the bottom of the mold is connected by a tube to a ladle containing the molten metal, which is sucked into the mold cavity when a vacuum is formed. Osborne 3583

Wethey furnace A multiple-deck, horizontal furnace for calcining sulfide ores. It resembles the Keller furnace. Fay wet metallurgy See: hydrometallurgy wet method Any hydrometallurgical process, such as the cyanide process, flotation process, etc. See also: wet process wet milling Comminution of ores and materials in the presence of a liquid in a suitable mill, either by rods, balls, or pebbles, or autogenously, by the material itself. See also: dry milling wet-milling plant A mill in which a wet process is employed. Fay wet-mill man See: wet-pan operator wet mining a. A system of mining in which water is sprayed into the air at all points where dust is liable to be formed, and no attempt is made to prevent the air from picking up moisture. It therefore soon becomes saturated and remains so throughout the ventilation circuit. Spalding b. Mining for salt and other water soluble minerals as brine rather than in the dry state. Kaufmann wet mixer See: clay maker wet-pan charger Person who adds water to mixture, in addition to clay, shale, or brick, in grinding pans in order to make it plastic. May be designated according to clay ground in pans, such as silica-wet-pan charger. Syn: wet-pan feeder 3584

wet-pan feeder See: wet-pan charger wet-pan operator Person who tends and supervises loading of wet pans used for grinding and tempering clay, performing essentially the same duties as described under dry-pan operator. Syn: clay temperer; wet-mill man. DOT wet-plant operator Person who works as a member of a crew performing any one or a combination of duties concerned with extracting cadmium, lead sulfate, and zinc oxide from dust recovered in Cottrell precipitators. DOT wet process A metallurgical process in which the valuable contents of an ore are dissolved by acid or other solvents; a leaching or lixiviation process. Opposite of dry process. See also: wet method wet puddling The ordinary process of puddling in which a furnace is lined with material rich in oxide of iron. Fay wet rot a. Timber decay set up when mine props have not been treated with zinc sulfate, etc., and are exposed to alternations of moisture and drying out. Pryor, 3 b. Timber decay caused by alternating wet and dry periods. wet screening The addition of water to a screen to increase its capacity and improve its sizing efficiency. Water may be introduced either by adding it to the feed stock or by spraying it over the material on the screen deck. The latter method is also used in rinsing or washing ores, etc., to recover minerals. Nelson wet separation A term used in connection with coal washing or other processes using fluid. See also: coal-preparation plant; washery. Nelson 3585

wet sieve analysis An American Society for Testing and Materials standard method of test, recommended for determining the grain sizing of materials in which slaking would occur. wet sphere device An instrument for assessing climatic conditions in mines, such as wet- and dry-bulb temperatures, air velocity, barometric pressure, and radiation. The field of usefulness of the instrument is limited to mines where the workers are normally sweating freely and wear few clothes. Roberts, 1 wettability The ability of a liquid to form a coherent film on a surface, owing to the dominance of molecular attraction between the liquid and the surface over the cohesive force of the liquid itself. AGI wettable sulfur Sulfur treated so that it is easily dispersed in water. USBM, 7 wetted perimeter The total length of surface in a channel or pipe that is in actual contact with water. See also: hydraulic mean depth wetterdynamite Originally, only guhr dynamites to which were added salts containing water of crystallization, such as Glauber's salts, ammonium oxalate, etc., with the view of making them available in mines containing combustible gases. Fay wetting A phenomenon involving a solid and a liquid in such intimate contact that the adhesive force between the two phases is greater than the cohesive force within the liquid. Thus, a solid that is wetted, on being removed from the liquid bath, will have a thin continuous layer of liquid adhering to it. Foreign substances, such as grease, may prevent wetting. Addition agents, such as detergents, may induce wetting by lowering the surface tension of the liquid. CF: water break wetting agent

3586

a. A reagent to reduce the interfacial tension between a solid and a liquid, so facilitating the spreading of the liquid over the solid surface. BS, 5 b. A chemical promoting adhesion of a liquid (usually water) to a solid surface. Pryor, 2 c. See: plasticizer d. Substance that lowers the surface tension of water and thus enables the water to mix more readily with other substances and so facilitates the spread of the liquid over a solid surface. BS, 5 wetting coal dust The spraying of mine roadways with water or treatment with a wetting agent in order to (1) increase the difficulty of raising the dust deposit into the air to take part in an explosion, and (2) reduce the flammability of the dust raised in an explosion. Nelson wetting effect a. When surface-active agents cause water to displace air at the surface of a solid-waterair system, the surface tension of the solid-water phase has been lowered in comparison with that of the solid-air phase, by adsorption of the wetting agent (adhesional wetting). For a small particle, wetting can be separated into three stages (adhesion, immersion, spread). Wetting is a preliminary step in deflocculation. Pryor, 3 b. A condition in which the surface tension of the solid-water phase is lowered in comparison with surface tension in the solid-air phase. wet unit weight The weight (solids plus water) per unit of total volume of soil mass, irrespective of the degree of saturation. Syn: mass unit weight See also: unit weight whaler A horizontal beam in a bracing structure. Nichols, 1 whale-type jib A coal-cutter jib that enables water to be taken, during cutting, to the back of the cut for dust suppression and prevention of gas ignition from frictional sparking. With an undercutting jib, it consists of a feed water pipe and four or five distributor pipes terminating in jets all arranged in the top plate of the jib. See also: undercut ignition; dust-suppression jib. Nelson wheal Corn. A mine. Nelson Wheatstone-bridge-type instrument 3587

An instrument that makes use of electrically heated filaments that burn methane and measure the heat output by resistance pyrometry. One or more filaments form the arms of a Wheatstone bridge circuit, the out-of-balance current being a function of the methane percentage. Roberts, 1 wheelbase The distance between the contact points on the front and back wheels of any vehicle and the surface upon which the vehicle travels. CTD wheel brae A flat or landing on the top of an incline. Fay wheel conveyor A series of wheels supported in a frame over which objects are moved manually or flow by gravity. See also: el conveyor; gravity conveyor; gravity wheel conveyor; portable conveyor. wheel ditcher a. A wheel equipped with digging buckets, carried and controlled by a tractor unit. Nichols, 1 b. A machine that digs trenches by rotation of a wheel fitted with toothed buckets. Nichols, 1 wheel dresser A tool for cleaning, resharpening, and truing the cutting faces of grinding wheels. Crispin wheeled tractor A tractor, fitted with large rubber-tired wheels, which can travel comparatively fast over rough ground. See also: tractor wheeler See: pusher wheelerite a. A yellowish resin, found in the Cretaceous beds of northern New Mexico, filling the fissures of the lignite, or interstratified in thin layers. It is soluble in ether. Fay b. A 3588

yellowish variety of retinite that is soluble in ether and fills fissures in, or is thinly interbedded with, lignite beds in northern New Mexico. wheel excavator A large-capacity machine for excavating loose deposits, particularly at opencast coalpits. It consists of a large digging wheel that rotates on a horizontal axle and carries large buckets on its rim. Nelson wheelman See: rollerman wheel ore See: bournonite wheel pit A pit in which the lower part of a flywheel runs. Webster 2nd wheelrace The place in which a water wheel is set. Webster 3rd wheel runner See: incline man wheel scraper A scraper mounted on an axle supported by a pair of wheels. It affords an easy means of conveying a loaded scraper to a dumping ground. See also: bowl scraper wherk Eng. A small unexpected turning in the stone, side, or ore, often accompanied by a small joint; Derbyshire. Arkell wherryite A monoclinic mineral, Pb4 Cu(CO3 )(SO4 )2 (Cl,OH,O)3 ; pale green; finely granular; related to caledonite; at the Mammoth Mine, AZ. whetstone 3589

Any hard fine grained rock, commonly siliceous, that is suitable for sharpening implements such as razors, knives, and other blades; e.g., novaculite. Whetwell stove A firebrick hot-blast stove on a regenerative system. Fay whewellite A monoclinic mineral, Ca(C2 O4 ).H2 O ; soft; in coal seams, incrustations on marble; also in human urinary tracts. Syn: oxacalcite which-earth Eng. A whitish earth found at Thame, Waterperry, and Adwell; mixed with straw, and used for sidewalls and ceilings; a natural mixture of lime and sand, flakes in water (like gypsum) without any heat. Arkell whim a. A large capstan or vertical drum turned by horsepower or steam power. Used to raise coal, water, etc., from a mine. Also called: whimsey; whim gin; horse gin. Fay b. Drum on which a hoisting rope is coiled. Also spelled wem. Pryor, 3 whim driver A laborer who drives a draft animal at the surface of a mine to supply power to a whim (large drum on which a cable is wound) used to hoist ore, coal, or rock in a shallow shaft. Becoming obsolete. DOT whim gin See: whim; horse gear. whim shaft A shaft through which coal, ore, water, etc., are raised from a mine by means of a whim. Zern whin a. Igneous rock. When parallel to the bedding planes, it is called a whinsill; when cutting across the strata, a whin dike. Nelson b. A hard, compact rock. Gordon c. Whinstone or whinrock. In Nova Scotia, miners apply this term to a thick-bedded rock composed of 3590

grains of quartz with argillaceous or feldspathic matter that resembles graywacke. Fay d. A whim or winch. Webster 2nd e. See: dolerite whin float a. Scot. A horizontal sill or lava flow of igneous rock. Arkell b. Scot. A kind of greenstone, basalt, or trap, occurring in coal measures. Fay whinny Resembling or abounding in whinstone. Fay whinstone A colloquial British term for dolerite, basalt, and other dark fine-grained igneous rocks. The term is derived from the Whin Sill in northern England. CF: trap whintin Cumb. Spotted schist. CF: calamanco; linsey. Arkell whip a. A rope that passes over a pulley and is pulled by a horse to hoist ore. Modern form occasionally seen has a car or lorry working backward and forward for shallow pitting. Called whip-and-derry when used with a derrick or gin. Pryor, 3; Fay b. One who operates such a hoisting apparatus. Standard, 2 c. See: rod slap whip-and-derry See: whip whip gin A gin block for use as a whip, as in hoisting. Standard, 2 whip out The enlargement of a portion of a borehole caused by the eccentric rotation and slap of the drill rods. Long whipper Person who raises coal, merchandise, etc., with a whip, as from a ship's hold. Standard, 2; Fay 3591

whipping a. The thrashing about of a moving rope, such as a hoisting cable in a mine shaft. Syn: surging b. Hoisting ore, coal, or other material by means of a whip. Fay whipping hoist A hoist worked with a whip, esp. if by steam power. Standard, 2 whipstock Wedge-shaped device used to deflect and guide a drill bit away from vertical; procedure of deflecting a hole. CF: arc cutter See also: deflection wedge whipstocking A term commonly used by petroleum-field drillers to designate the act or process referred to by diamond drillers as deflecting a borehole. See also: wedging whipstock point The point within a borehole at which a deflection or change in course is desired. Long whirling hygrometer In mining, a hygrometer used to obtain wet-bulb temperatures. The hygrometer is spun round and round at a speed of about 200 rpm, for at least 1 min, and then read as quickly as possible. See also: Storrow whirling hygrometer whirlstone Eng. Usually applied to sandstone (not a freestone) in the Carboniferous Limestone Series of Cumberland. Sometimes applied to a dolomite, limestone, or shale. Arkell whistler See: squealer white The color of the mixture of electromagnetic radiation visible to the normal human eye. White is commonly, but incorrectly, applied to colorless minerals and gemstones. white agate 3592

See: chalcedony white alkali An older term for accumulation of salts with high levels of sodium that may develop as a crust. CF: black alkali white antimony See: valentinite; valentite. white arsenic Commercially called arsenic. Arsenic trioxide, As2 O3 ; the most important compound of arsenic. Obtained from the roasting of arsenical ores. See also: arsenic trioxide white Bengal fire A very brilliant light produced by burning pure metallic arsenic. Fay white cast iron Cast iron that gives a white fracture because the carbon is in combined form. See also: iron white clay See: kaolin white coal a. See: tasmanite b. Water power: a French designation (houille blanche). Standard, 2 white cobalt A name frequently applied to smaltite and cobaltite. See also: cobaltite; smaltite. Fay white copper A white alloy of copper; paktong. Usually German silver. Syn: domeykite Webster 2nd; Fay; Hey, 1 white copperas See: coquimbite; goslarite. 3593

white copper ore See: kyrosite white-countered gutta percha A safety fuse in which the powder is enclosed in a thin tube of gutta percha, which in turn is enveloped in a waterproof textile covering. Abbreviated W.C.G.P. Higham white damp Carbon monoxide, CO. A gas that may be present in the afterdamp of a gas- or coal-dust explosion, or in the gases given off by a mine fire; also one of the gases produced by blasting. It is an important constituent of illuminating gas, supports combustion, and is very poisonous because it is absorbed by the hemoglobin of the blood to the exclusion of oxygen. See also: damp white feldspar See: albite white flat Small, pale, rough nodule in hard shale in Shropshire. Arkell white garnet a. See: leucite b. A translucent variety of grossular resembling white jade in appearance. white gold Gold alloyed with nickel or palladium to give it a white color. CTD white gunpowder A mixture of 2 parts potassium chlorate, 1 part potassium ferrocyanide, and 1 part sugar. Syn: white powder white heat A common division of the color scale, generally given as about 2,800 degrees F (1,540 degrees C). white horse 3594

A term used by quarrymen to denote a light-colored gneiss, aplite, or pegmatite. Fay white-hot A state in which a material is heated to full incandescence so as to emit all the rays in the visible spectrum in such proportion as to appear dazzling white. Fay White-Howell furnace A revolving, cylindrical furnace for calcining calamine. Fay white iron An extremely hard cast iron, resulting when a casting is chilled in a metallic mold. See also: gray iron white iron ore An early name for siderite. See also: siderite white iron pyrites See: marcasite white latten An alloy of copper, zinc, and tin in thin sheets. Standard, 2 white lead Basic lead carbonate or lead hydroxycarbonate. CTD white lead ore a. See: cerussite b. A decomposition product of sphalerite. See also: white vitriol Syn: lead carbonate White Lias The Upper Rhaetic, as opposed to the overlying Blue Lias. Arkell white limestone The principal limestone division of the Great Oolite Series. Arkell 3595

white metal a. A general term covering a group of white-colored metals with relatively low melting points (lead, antimony, bismuth, tin, cadmium, and zinc). Includes the alloys based on these metals. ASM, 1 b. A copper matte of about 77% copper obtained from smelting sulfide copper ores. ASM, 1 c. Usually a tin-base alloy (more that 50% tin); used for lining bearings and winding rope cappels. Nelson white-metal cappel A cappel in which the end of the winding rope (separated into a brush) is embedded in a plug of white metal inside a socket. See also: capping Nelson white-metal capping A winding rope capping formed by opening out the wires of the rope for a length equal to that of the socket, cleaning them thoroughly of all grease, cutting out the hemp core, and finally drawing them into the warmed socket and running in the white metal, which is an alloy of lead, antimony, and tin. Mason white mica See: muscovite white mineral press A machine for briquetting flue dust. Fay white mundic See: arsenopyrite white nickel See: rammelsbergite; nickel-skutterudite. white nickel ore See: chloanthite white olivine The mineral forsterite, Mg2 SiO4 . Fay white opal 3596

Precious opal of any light color, as distinguished from black opal; e.g., a pale blue-white gem variety of opal. white ore See: cerussite white powder See: white gunpowder white pyrite See: marcasite; arsenopyrite. white salt a. Salt dried and calcined; decrepitated salt. Fay b. Salt refined and prepared mainly for household use. Also, vacuum pan salt used for salting skins; distinguished from rock salt. Kaufmann white sand Sand that is usually quartzitic and pure enough to resist heat and slags; used for the final layer in Siemen's steel furnaces. Nelson white schorl See: albite white smoker A plume of hydrothermal fluid issuing from the crest of an oceanic ridge; e.g., the East Pacific Rise at the mouth of the Gulf of California. The fluid is clouded by white precipitates, mostly barite and silica. It issues at rates of tens of cm/second and at temperatures of 100 to 350 degrees C (Macdonald et al., 1980). CF: black smoker white tellurium See: sylvanite; krennerite. white tin Metallic tin after smelting, in contradistinction to black tin or cassiterite. Fay 3597

white tombac A variety of brass made white by the addition of arsenic. Standard, 2 white vitriol The mineral goslarite, ZnSO4 .7H2 O . Also called: salt of vitrol; zinc vitrol. CTD; Fay whiting substitute A finely ground calcium carbonate, about 98% pure, contaminated by magnesia, silica, iron, or alumina. This material should not be confused with chalk whiting or precipitated chalk. USBM, 7 Whiting system A system in which two parallel, grooved sheaves are coupled. These sheaves are driven directly from a hoisting engine. One sheave is set at a slight angle to the vertical so that the rope will pass freely from one sheave to the other. The hoisting rope passes around the drive sheaves and then to a takeup sheave, which is mounted on a horizontally movable carriage to take up slack or to change the hoist from one level to another. A tail rope is used in this system, although it may not be absolutely necessary. Lewis whitlockite A trigonal mineral, Ca9 (Mg,Fe)H(PO4 )7 ; colorless; forms rhombohedra; at North Groton, NH. Syn: merrillite Whitney stress diagram Diagram showing the stress distribution in a reinforced concrete beam in accordance with the theory of ultimate load. Hammond Whitwell stove A firebrick, hot-blast stove on a regenerative system. Fay whizzer mill See: Jeffrey crusher whole body counter

3598

A device used to identify and to measure the radiation in the body (body burden) of humans and animals. Uses heavy shielding to keep out background radiation, ultrasensitive scintillation detectors, and electronic equipment. Lyman whole-circle bearing A bearing that defines the direction of a survey line by its horizontal angle measured clockwise from true north. Hammond whole diamond A diamond (as mined), the shape of which has not been modified artificially. Syn: whole stone whole stone See: whole diamond whole-stone bit A bit, the crown of which is either surface set or impregnated with whole diamonds, as opposed to an impregnated or surface-set bit in which the inset diamonds are fragmented diamonds. Long wich Celtic for salt spring; often used in England as the termination of names of places where salt is or has been found; e.g., Droitwich, Nantwich. Syn: wych wichert A subsoillike chalk, Haddenham, near Thame, U.K. wick To place a soft twisted-cotton string between rod joints as they are made up or coupled. Long wicket a. N. Wales. A kind of pillar-and-stall, or bord-and-pillar, system of working a seam of coal, with pillars up to 15 yd (13.7 m) apart and stalls up to 24 yd (22.0 m) wide. Also called wicket work. Fay b. A wall built of refractories to close an opening into a kiln or furnace; it is of a temporary nature, serving as a door; e.g., in intermittent or annular kilns. Dodd 3599

wicket conveyor A conveyor comprising two or more endless chains connected by crossbars and to which vertical rods are attached at spaced intervals. The crossbars are also provided with spaced projections at the same level to form in effect a continuous carrying surface through which product cannot fall. wicking The soft twisted-cotton string used to wick drill-rod joints; the act of placing the cotton string on the rod joints. See also: wick Long wide-mouthed socket A fishing tool similar to a bell-mouth socket, but lacking a latch. Long wide opening An underground excavation whose width is greater than two or three times its height. Woodruff widiyan See: wadi widowmaker A rock drill operated without water and hence, produces a lot of dust, leading to silicosis; often fatal to a miner. width of lode The thickness of ore measured at right angles to the dip. The term "true width" is often used to describe this value, in which case width of lode is used to denote the thickness passed through, irrespective of the angle of dip. Nelson Wiedgerite Trade name for a soft bitumen resembling elaterite, but containing much sulfur and water. Tomkeieff wiggle stick See: divining rod 3600

wiggle tail a. A rock-cutting tool or bit, used to deflect a borehole, that has an articulated pilot part, which also can be attached to a knuckle-jointed device and coupled to the bottom end of a drill string. Also called whipstock. Long b. Nickname for hand-rotated stoper drill. wightmanite A monoclinic mineral, Mg5 (BO3 )O(OH)5 .2H2 O; colorless; forms pseudohexagonal prisms; at Commercial quarry, Crestmore, CA. Wilcoxian Lower or upper lower Eocene. AGI wildcat a. A borehole and/or the act of drilling a borehole in an unproved territory where the prospect of finding anything of value is questionable. It is analogous to a prospect in mining. Long b. A mining company organized to develop unproven ground far from the actual point of discovery. Any risky venture in mining. wildcat drilling The drilling of boreholes in an unproved territory. Also called: cold nosing; wildcatting. Long wildcatter a. An individual or corporation devoted to exploration in areas far removed from points where actual minerals or other substances of value are known to occur. Also called cold noser. See also: wildcat b. One who locates a mining claim far from where a deposit has been discovered or developed. wilderness a. An area or tract of land that is uncultivated and uninhabited by people. b. North American stage: Middle Ordovician (above Porterfield, below Barnveld; it includes uppermost Black River and Rockland rocks). c. Mottled red and gray grit at Forest of Dean, U.K. wild heat A heat of molten steel that is boiling violently, and so, if poured, honeycombs an ingot with contained gases. Webster 2nd 3601

wild lead See: sphalerite wild steel a. Steel in, or made from, a wild heat. Webster 2nd b. Said of liquid steel, esp. rimmed steel, that is producing considerable effervescence. Henderson wild work A type of bord-and-pillar system of coal mining in which the very narrow pillars left to support the roof are not recovered. Fay Wiles' process A method of reducing iron ores in which an electric furnace is fitted with two or more hollow electrodes, through which the finely divided ore, intimately mixed with reducing materials, is introduced. Osborne Wilfley slimer A form of shaking canvas table that is given a vanner motion. Liddell Wilfley table Long-established and widely used form of shaking table; rectangular; mounted horizontally and can be sloped about its long axis. It is covered with linoleum (occasionally rubber) and has longitudinal riffles tapering at the discharge end to a smooth cleaning area, triangular in the upper corner. A compound eccentric is used to create a gentle and rapid throwing motion on the table, longitudinally. Sands, usually classified for size range, are fed continuously and worked along the table with (1) the aid of feedwater, and (2) across riffles downslope by gravity tilt adjustment and added wash water. At the discharge end, the sands have separated into bands: the heaviest and smallest uppermost; the largest and lightest lowest. The Dodd, Cammet, Hallett, and Woodbury are similar types of tables. See also: Woodbury table Wilkinite Trade name for a colloidal bentonite (jelly rock) used in papermaking. Also spelled Wilconite. willemite

3602

A trigonal mineral, Zn2 SiO4 ; white to pale tints; fluoresces bright yellow; in zinc deposits in New Jersey, New Mexico, Africa, and Greenland; a source of zinc. Syn: belgite willen stone a. Eng. An oolitic freestone used for cornices and chimney pieces; also, a good paving stone, Halston, Northamptonshire. Arkell b. A massive yellow to green, impure variety of antigorite resembling jade; used for decorative purposes. It commonly contains specks of chromite. c. An old "misspelling" of willemite. Williams' hinged-hammer crusher A crusher with a rotating central shaft, carrying a number of hinged hammers that fly out from centrifugal force, crushing the feed against the casing. Syn: hinged-hammer crusher williamsite a. An apple-green impure variety of serpentine. See also: jade Sanford b. A translucent bright green serpentine, usually containing specks of chromite, used as a semiprecious stone. Dana, 1 c. An old misspelling of willemite. Dana, 1 Wilmot jig A basket-type jig, the basket being suspended in a tank of water. Pulsations are effected by moving this basket upward and downward by means of eccentrics. Has been used extensively in the preparation of anthracite of all sizes and, to a lesser extent, of bituminous coal. Mitchell Wilputte oven A byproduct coke oven having two outer zones in the heating system and one double inner zone. In this oven, the gas is alternately burned upwards in the two outer zones with the products of combustion being carried down through the double inner zone and, on reversal, burned upwards in the double inner zone with the products of combustion being carried down through the two outer zones. Known as a double-divided oven. Camp wilsonite a. A purplish-red material consisting of an aluminosilicate of magnesium and potassium; represents an altered scapolite. AGI b. A tuff composed of fragments of pumice and andesite in a matrix of vitric and granular material (Holmes, 1928). AGI Wilton stopper 3603

Automatic arrangement that arrests a mine car when it runs away downslope. The car displaces a pendulum beyond its nonactivating limit of swing and a pivoted rail then falls between the rail tracks below. Pryor, 3 wiluite a. A green variety of grossular garnet. b. A greenish variety of vesuvianite. win a. To extract ore or coal. To mine, to develop, to prepare for mining. b. To recover (as metal) from ore. Webster 3rd winch a. A small hand- or power-operated drum haulage used for light-duty work in surface and underground mines. A heavy-duty power winch fitted to the rear of a tractor. See also: pickrose hoist b. Syn: hoist of a horizontal drum with rank handles. Long c. A drum that can be rotated so as to exert a strong pull while it is winding the attached line. Nichols, 1 d. A small drum haulage or hoist. A gear train is interposed between the handle and the drum. The handle is turned several revolutions to one revolution of the drum. Two handles and a pawl and ratchet may be fitted to prevent the load from running back should the pressure on the handle be reduced. See also: monkey winch winchellite See: mesolite winchman In metal mining, a person who operates a power-driven winch on a gold dredge to move it from one working position to another during dredging operations, winding up the cables anchored at points in advance of the dredge. DOT winch operator See: hoist operator wind To hoist or raise coal or ore; to spool rope or cable on the drum of a hoist. wind beam

3604

A beam incorporated into a structure for the sole purpose of resisting wind pressure. Hammond wind blast A blown-out or "windy" shot. Fay wind box In blast furnace operation, the compartment in the bottom of the converter that receives the blast and delivers it to the tuyeres. Mersereau, 2 winder a. An electrically driven winding engine for hoisting a cage or cages up a vertical mine shaft. CTD b. See: card tender winder brake An appliance or piece of equipment capable of retarding or stopping cages in a shaft in an emergency. See also: brake; post brake; semiautomatic control. Nelson wind furnace Any form of furnace using the natural draft of a chimney without the aid of a bellows or blower. Fay wind gage An anemometer for testing the velocity of air in mines. wind hatch In mining, an excavation or opening for removing ore. Standard, 2 winding The operation of hoisting coal, ore, miners, or materials in a shaft. The conventional method is to employ two cages actuated by a drum type of winding engine. Steel ropes are attached at either end of the drum, one over and the other under it, so that as one cage ascends, the other descends. Thus the cages arrive at pit top and bottom simultaneously. See also: automatic cyclic winding; balanced winding; balance rope; deep winding; Koepe winder; winding cycle; winding rope. Nelson winding apparatus 3605

The machinery and equipment used to lower and raise loads through a shaft. Nelson winding cycle In general, a cycle refers to any series of changes or operations in which any part of the system return to its original state or position. In winding, the term usually refers to a complete wind, which is comprised of three phases: (1) acceleration to full speed; (2) full-speed running; and (3) retardation to rest. The period of the winding cycle is the sum of winding time and decking time in seconds. See also: winding speed Nelson winding drum For haulage to the surface through a mine shaft, the surface gear includes a winding drum of cylindrical or cylindroconical form on which the winding rope (hoisting rope) is coiled as the cage, or skip or kibble, is raised, and from which it is paid off as the return journey is made. Two such receptacles are usually worked simultaneously in balanced hoisting, one rising as the other descends, from a compound drum. The drum is driven by the winding engine. See also: bicylindroconical drum; conical drum; Koepe sheave; parallel drum; winding engine. Pryor, 3 winding engine a. A steam or electric engine at the top of a shaft that powers the winding drum, thus hoisting and lowering a cage or skip by means of a winding rope. In metal mining, the winding engine is usually called a hoist. Also called: winder. See also: hoist b. See: winding drum winding engineman A skilled person in charge of the steam or electric winding engine at a mine. Also called hoistman. Nelson winding guide The purpose of a winding guide is to permit winding to proceed safely at relatively high speeds by preventing collisions between the cages and between cages and the side of, or fittings in, a shaft. It must be (1) rigid enough to prevent material deviation of the cages or skips from the vertical; (2) strong, since a broken guide causes danger from damage; (3) smooth, so as to offer as little resistance to the movement of a cage as possible; and (4) firmly supported and maintained vertical. Guides may be of two types, rigid or flexible. The former may be of timber, and in new shafts have generally been replaced by steel channels, steel rails or angles; the latter are steel ropes of round or semilocked section steel rods. Rigid guides are adopted in shafts of rectangular cross section; these and the shaft sides and fittings are small. Rope guides are used in circular and elliptical shafts where adequate clearances can be provided. Rope guides maintain the vertical 3606

automatically, and expand and contract with temperature variation without complication. Sinclair, 5 winding pulley See: winding sheave winding rope The rope that carries a cage, skip, or hoppit in a shaft. The wires are twisted together symmetrically according to a definite geometrical pattern. See also: wire rope; winding drum. Syn: lay of rope Nelson winding sheave A grooved pulley wheel, mounted on plummer blocks, at the top of the headgear. The winding rope passes from a cage or skip around the sheave and onto the winding drum. For normal loads, the sheave rim and boss are made of castiron, and the spokes are made of round, mild steel. Winding sheaves range up to about 24 ft (7.32 m) in diameter. Sheaves up to 8 ft (2.44 m) in diameter are usually made in one piece, but above this size, they are built in halves and bolted together. To give efficient service, the sheave diameter should be at least 96 times the winding rope diameter. See also: head sheave; Koepe sheave. Syn: hoisting sheave Nelson winding speed The velocity at which a winding engine lifts a cage or skip in a shaft. Winding speeds reach up to 6,000 ft/min (1.8 km/min) for deep mines. The normal maximum speed for deep shafts is 3,500 to 4,000 ft/min (1.1 to 1.2 km/min) and for geared winders, 1,500 to 3,000 ft/min (0.46 to 0.91 km/min). Nelson windlass a. A device used for hoisting; limited to small-scale development work and prospecting because of its small capacity. Lewis b. A drum or a section of tree trunk set horizontally on rough bearings above a shallow pit or shaft; used to raise or lower buckets of spoil in exploratory work. Handles at each end of the drum allow for manual rotation. Pryor, 3 wind method An air-blowing system of separating coal into various sizes, and extracting waste from it, which in principle depends on the specific gravity or size of the coal and the strength of the current of air. windmill anemometer 3607

An anemometer in which a windmill is driven by the air stream, and its rotation is transmitted through gearing to dials or other recording mechanism. In some instruments, the rotating vanes and dials are in the same plane; i.e., both vertical, while in others the dial is horizontal. In the windmill type, the operation of air measurement involves readings of dials at the beginning and end of a measured period. Windmill instruments may be fitted with an extension handle, providing a form of remote control; used to measure air speed in an otherwise inaccessible spot. Mason window An eroded area of a thrust sheet that displays the rocks beneath it. Syn: fenster window pipe A dredge discharge pipe with one or more openings in the bottom. Nichols, 1 window-type sample See: door-type sampler wind pressure The pressure on a structure due to wind, which increases with wind velocity approx. in accordance with the formula p = 0.003 v2 , where p is the pressure in pounds per square feet of area affected, and v is the wind velocity in miles per hour. Hammond wind road Underground ventilation road. See also: airway wind rose A diagram which shows the proportion of winds blowing from each of the main points of a compass at a given locality, recorded over a long period. The prevailing wind with its average strength is thereby revealed at a glance. Hammond windrow a. A row of peats or sod set up to dry, or cut in paring and burning. Standard, 2 b. A ridge of soil pushed up by a grader or bulldozer. Hammond winds See: winze 3608

windup The amount of twist occurring in a string of drill rods when the string is rotated during drilling. There can be as many as several complete revolutions of the rod at the collar before the bottom member of the string begins to rotate. Also called wrap-up. Long windy shot A blast in a coal mine which--due to improperly placed charges, the wrong kind or quantity of explosives, or insufficient stemming--expends most of its force on the mine air; it sometimes ignites a gas mixture, coal dust, or both, thus causing a secondary explosion, which may or may not spread throughout the mine; a shot that blows out without disturbing the coal; a shot that is not properly directed or loaded; a blown-out shot. Fay wing a. The side or limb of an anticline. Fay b. See: catch; chair; dog; rests; wing. wing belt tripper A belt conveyor tripper having auxiliary conveyors extending laterally to one or both sides to provide wider distribution of bulk material being discharged. wing dam See: pier dam winged pillar Scot. Pillar of coal that has been reduced in size. Fay wingwall A wall that guides a stream into a bridge opening or a culvert barrel. Nichols, 1 winklestone Warty, elongate pyrite nodule, Essex, U.K. winning a. The excavation, loading, and removal of coal or ore from the ground; winning follows development. Nelson b. The operation of mining an ore and opening up a new portion of a coal seam. CTD c. The portion of a coalfield laid out for working. Fay d. The 3609

combined process of excavating and transporting a raw material such as clay to a brickworks or stockpile. Dodd winning heading A development heading off which oblique headings and conveyor panels are formed and worked (longwall); any of the development drivages in the solid coal, about 15 yd (13.7 m) apart, and of which bords and pillars are formed (pillar method of working). Nelson winnowing gold Air blowing. Tossing up dry powdered auriferous material in air, and catching the heavier particles not blown away. Fay winter dumps A term used in Alaska to describe gold-bearing gravel mined during the winter and stored on the surface for sluicing in the spring and summer. Fay winze a. A vertical opening driven downward connecting two levels in a mine. When one is standing at the top of a completed connection the opening is referred to as a winze, while when standing at the bottom, the opening is a raise, or rise. Syn: winds b. A subsidiary shaft that starts underground. It is usually a connection between two levels. Syn: way shaft c. Can. Interior mine shaft. Hoffman wire a. A continuous length of metal drawn from a rod. Hammond b. War. A haulage rope. Fay c. See: capillary wirebar A cast shape, particularly of tough pitch copper, which has a cross section approx. square with tapered ends; designed for hot rolling into a rod for subsequent drawing into wire. ASM, 1 wire cloth Screen composed of wire or rod woven or crimped into a square or rectangular pattern. Nichols, 1 wired glass 3610

A form of sheet glass produced by rolling wire mesh into a ribbon of glass so that it acts as a reinforcement and holds the fragments together in the event of the sheet being fractured. CTD wire drag A buoyed wire towed by a ship at a given depth to determine whether any isolated rocks, small shoals, etc., extend above that depth, or for determining the least depth of an area. Hunt wire gage a. A gage for measuring the diameter of wire. Fay b. A standard series of sizes used in the manufacture of wire (diameter) or sheet metal (thickness) and indicated by arbitrary numbers. Fay c. A notched plate having a series of gaged slots, numbered according to the sizes of the wire and sheet metal manufactured; used for measuring the diameter of wire. The gage most widely used in the United States is the U.S. Standard Steel Wire, which name has official sanction, without legal effect. The Birmingham gage is recognized in acts of Congress for tariff purposes. Two gages (American Gage; Browne and Sharpe's) are used for copper wires and all nonferric metal wires. Crispin wire gauze A gauzelike texture of fine wire, such as that used for the chimneys of flame safety lamps. Fay wire hanger The hanger from which wire or cable is suspended. wire line a. As used in a general sense, any cable or rope made of steel wires twisted together to form the strands. Specif., a steel wire rope 5/16 in (7.9 mm) or less in diameter. See also: cable b. A general term for any flexible steel line or cable drill connecting a surface winch to a tool assembly lowered in a well bore. Also spelled wireline. AGI wire-line barrel See: wire-line core barrel wire-line cable A wire rope 3/16 in or 1/4 in (4.8 mm or 6.4 mm) in diameter; used to handle the inner tube of a wire-line core barrel. See also: cable Long 3611

wire-line core barrel Double-tube, swivel-type core barrel; available in various outside diameters corresponding to sizes of diamond- and rotary-drill boreholes; designed so that the innertube assembly is retractable. At the end of a core run, the drill string is broken at the top joint so that an overshot latching device can be lowered on a cable through the drill-rod string. When it reaches the core barrel, the overshot latches onto the retractable innertube assembly, which is locked in the core barrel during the core run. The upward pull of the overshot releases the inner tube and permits it to be hoisted to the surface through the drill rods; it is then emptied and serviced and dropped or pumped back into the hole, where it relocks itself in the core barrel at the bottom. Syn: wire-line barrel Long wire-line coring The act or process of core drilling with a wire-line core barrel. See also: wire-line core barrel wire-line dredging In this method, digging tools or buckets are suspended on a steel cable and lowered to the sediment surface, where they are loaded and retrieved. Includes the use of dragbucket and clamshell dredges, and generally to a depth of not more than 500 ft (152 m) below sea level. Mero wire-line drilling The drilling of boreholes with wire-line core-barrel drill-string equipment. Long wire-line drill rod Drill rod having couplings that are nearly flush on the inside and designed so that the inner tube of a wire-line core barrel and overshot assembly can be run inside the rod. Long wireline drill-rod coupling A rod coupling designed for use on wire-line drill rods. See also: wire-line drill rod; wire-line core barrel. Long wire-line drum A winding drum or hoist on which the wire line is wound when handling the inner tube and overshot assemblies of a wire-line core barrel. Syn: wire-line hoist wire-line hoist 3612

See: wire-line drum wire-line log See: well log wire-line socket The socket connecting the wire line to a wire-line core barrel overshot assembly. Long wireman In mining, a person who installs and repairs underground power, light, and trolley lines, making extensions into new working places as openings advance. Also called lineman; mine wireman; wire hanger. DOT wireman helper In mining, one who assists a wireman in installing and repairing underground power, light, telephone, and trolley lines. Also called wire-hanger helper. DOT wire-mesh conveyor belt A woven-wire conveyor belt composed of various combinations of flattened-helical coils of wire, which may or may not be joined by straight or crimped members. wire-mesh reinforcement Expanded metal, wire, or welded fabric used as reinforcement for concrete or mortar. See also: mesh wire pack A circular pack consisting of waste stone built within woven fencing fixed to light props. The pack is still effective as support after the props have failed. Wire packs, e.g., are used for small openings in the Rand mines in South Africa. Nelson wire rod Hot-rolled coiled stock that is to be cold-drawn into wire. ASM, 1 wire rope a. A rope made of twisted strands of wire for winding in shafts and underground haulages. Wire ropes are made from medium carbon steels. See also: cable; flattened 3613

strand rope; locked coil rope; multiple-strand rope; winding rope. Long b. Various constructions of wire rope are designated by the number of strands in the rope and the number of wires in each strand. The following are some common terms encountered: airplane strand; cable-laid rope; crane rope; elevator rope; extra-flexible hoisting rope; flat rope; flattened-strand rope; guy rope; guy strand; hand rope; haulage rope; hawser; hoisting rope; Lang lay rope; lay; left lay rope; left twist; nonspinning rope; regular lay; reverse-laid rope; rheostat rope; right lay; right twist; running rope; special flexible hoisting rope; standing rope; towing hawser; transmission rope. Hunt wire-roper anchor A device for tieing off and securing the tension in the wire ropes of a wire-rope, sideframed, intermediate section. NEMA, 2 wire-rope side-framed intermediate section An intermediate section consisting of interchangeable increments or parts in which the carrying idlers are supported by one or more steel wire ropes. Return idlers may or may not be supported from the ropes. NEMA, 2 wire-rope spreader That part of a wire-rope, side-framed intermediate section that maintains a horizontal plane a fixed distance between wire ropes but does not support the wire ropes. (NEMA, 1961) wire-rope support That part of a wire-rope, side-framed intermediate section that positions the wire rope or ropes with respect to the roof or floor. It may or may not have provisions for mounting a return idler. NEMA, 2 wire ropeway A ropeway using a wire cable or cables. Used for conveying ore and supplies in rough mountainous districts; a wire tramway. See also: aerial tramway wire saw A saw consisting of one- and three-strand wire cables up to 16,000 ft (4.9 km) long running over pulleys. When fed by a slurry of sand and water and held against rock by tension, the saw cuts narrow, uniform channels by abrasion. This saw is used for cutting granite, slate, marble, limestone, or sandstone blocks. USBM, 7 wire-saw operator 3614

See: wire sawyer wire sawyer In a stonework industry, a person who operates a wire saw to cut very large blocks of granite, limestone, marble, slate, or sandstone into smaller blocks that can be handled on gang or circular saws. Also called wire saw operator. DOT wire setter Person who tends electrically powered unwinding machine that supplies wire netting to be embedded in sheet glass. DOT wire silver Native silver in the form of wires or threads. AGI wire strand Several steel wires twisted together to form one strand of a wire rope or cable. Long wire-strand core A core in which the number of wires shall not be less than the number of wires in a main strand of the wire rope, and the individual wires shall be of an appropriate grade of steel in accordance with the best practice and design, either bright (uncoated), galvanized, or drawn galvanized wire. See also: independent wire rope core wiry Occurring as thin wires, often twisted like the strands of a rope; e.g., native copper. witching stick See: divining rod withamite A red to yellow variety of epidote with a little manganese; in andesites at Glencoe, Scotland. CF: piemontite withdraw To draw off; to take out supports. Mason 3615

withdrawal Segregation of particular lands from the operation of specified public land laws, making those laws inapplicable to those lands. Lands may be withdrawn from all or any part of the public land laws, including the mineral location and mineral leasing laws. SME, 1 witherite An orthorhombic mineral, BaCO3 ; aragonite group; colorless to milky; in lowtemperature hydrothermal veins. Syn: carbonate of barium witness corner A marker set on a property line leading to a corner; used where it would be impracticable to maintain a monument at the corner itself. Seelye, 2 witness mark A mark or stake set to indicate the position (approximate or exact) of a property corner, instrument station, or other survey point. A witness may be a rock, tree, or other object; e.g., a blazed tree on the bank of a river to indicate a corner at the intersection of some survey line with the center line of the stream, which, therefore, cannot be marked directly; a stake driven so as to stand out; and a stake marked with a station number, driven flush with or below the surface of the ground. Seelye, 2 witness post Satellite beacon used to mark a claim when the correct boundary post is inaccessible. Pryor, 3 wittichenite An orthorhombic mineral, Cu3 BiS3 ; gray to tin-white; at Wittichen, Baden, Germany. Also called wittichite. wittite A monoclinic mineral, Pb9 Bi12 (S,Se)27 ; lead-gray; at Falun, Sweden. Witton-Kramer magnet A circular magnetic separator suspended over a conveyor head pulley to extract small pieces of tramp iron. Nelson Witwatersrand 3616

The gold-mining district, now usually called the Rand, in South Africa. Nelson wobble wheel roller A skip body mounted on nine or more oscillating, smooth, rubber-tired wheels for compaction and fine rolling of soil. Nelson wodginite A monoclinic mineral, (Ta,Nb,Sn,Mn,Fe)16 O32 ; dimorphous with ixiolite; occurs in granite pegmatites; named for Wodgina, Australia. woehlerite a. A monoclinic mineral, Ca2 NaZr(Si2 O7 )(O,OH,F)2 . b. The organic matter in carbonaceous chondrites. Also spelled woehlerite. Woehler test A fatigue test in which one end of a specimen is held in a chuck and rotated in a ball bearing placed on the other end. The ball bearing carries a weight and, as the specimen rotates, the stress at each point on its surface passes through a cycle from a maximum in tension to a maximum in compression. CTD wold A range of hills produced by differential erosion from inclined sedimentary rocks; a cuesta. CF: cuesta Wolf a. The name of a naphtha-burning flame safety lamp. Jones, 1 b. The name of carbide and electric lamps. wolfachite A mineral (not established as a species), Ni(As,Sb)S , intermediate between gersdorfite and ullmannite; occurs at Wolfach, Baden, Germany. wolf cut point See: equal-errors cut point wolfeite 3617

A monoclinic mineral, (Fe,Mn)2 (PO4 )(OH) ; forms a series with triploidite; dimorphous with satterlyite. Wolf nickel-cadmium battery While other nickel-cadmium batteries generally adopt either tubular or pocketed positive plate construction, the Wolf battery has individual features of interest. The supporting medium for the active materials consists of strips of compressed corrugated nickel foil. The method of construction is to perforate strips of the foil, which are pasted with active material. The strips are folded into corrugations and compressed into a cake. Two or more cakes are mounted in a pure nickel frame to form the finished plate. This method of construction results in a plate of satisfactory electrical conductivity, and no admixture of graphite or flake nickel in the active material is necessary. Roberts, 2 Wolf process A flotation process invented by Jacob D. Wolf in 1903. He used sulfochlorinated or other oils and aimed to secure a high extraction with a low grade of concentrate in the first step, and by washing with hot water to concentrate the concentrate in a second step. Apparently no commercial use was made of it. Liddell wolfram See: wolframite; tungsten. wolframine See: tungstite; tungstic ocher; wolframite. wolframite A monoclinic mineral, (Fe,Mn)WO4 ; within the huebnerite-ferberite series; pseudoorthorhombic due to twinning. See also: tungsten Syn: wolfram wolfram lamp A tungsten lamp. Webster 3rd wolfram ocher See: tungstic ocher wolfsbergite See: chalcostibite; jamesonite. 3618

wollastonite A triclinic mineral of the pyroxenoid group: CaSiO3 . It is dimorphous with parawollastonite. Wollastonite is found in contact-metamorphosed limestones, and occurs usually in cleavable masses or sometimes in tabular twinned crystals; it may be white, gray, brown, red, or yellow. It is not a pyroxene. Symbol, Wo. Syn: tabular spar AGI wollongite See: wollongongite wollongongite A coallike shale similar to torbanite. It is named from its type locality, Wollongong, New South Wales, Australia. Also spelled wollongite; wallongite. AGI woelsendorfite An orthorhombic mineral, (Pb,Ca)U2 O,.2H2 O ; forms bright red crusts on fluorite; at Woelsendorf, Bavaria, Germany. Wommer safety clamp A type of foot operated drill-rod safety clamp, the operation of which is similar to a bulldog safety clamp. Also called automatic spider. Long wonder metal Applied to metals, such as beryllium, magnesium, titanium, and zirconium, that were put into expanded use following World War II. Pearl wood agate A term used for agatized wood, esp. agate formed by siliceous permineralization of wood. AGI Woodbury jig A jig with a plunger compartment at the head end, so that the material is given a classification in the jig. Liddell Woodbury table

3619

A table of the general Wilfley-Overstrom-Card type, with riffles parallel to the tailings side, and a hinged portion without riffles (unlike the Card). The table top is a rhomboid, and the riffles gradually shorten as they near the tailings side. See also: Wilfley table wood chain S. Staff. A hoisting chain, the iron links of which are filled with small blocks of wood. Fay Wooddell scale A scale of resistance to abrasion based on the following method: if specimens of different materials are mounted so that they present surfaces substantially in the same plane, and if the surfaces are subjected to a lapping operation with a properly selective abrasive, the harder materials will stand out in relief, whereas the softer ones will be cut or worn to a depth, depending upon their hardness. By averaging several readings, a scale of hardness was established by which the quantitative values of the hardness of various materials could be determined. On the Woodell scale, diamond has approx. 2 times the hardness of boron carbide, 3.5 times that of tungsten carbide, and nearly 5 times that of corundum. Chandler wooden tubbing Consists of wooden staves driven down in soft ground during sinking to keep back water. The lining is stated to be capable of withstanding pressures up to a maximum of 130 psi (896 kPa). The lining resembles the sides of a wooden tub and the word tubbing is doubtless derived from this similarity. See also: tubbing wood hematite A finely radiated variety of hematite exhibiting alternate bands of brown or yellow of varied tints. Fay woodhouseite A trigonal mineral, CaAl3 (SO4 )(PO4 )(OH)6 ; beudantite group; forms small colorless rhombohedra. wood iron A fibrous variety of chalybite (siderite), FeCO3 . Fay wood iron ore Corn. Fibrous limonite; Land's End district. Arkell 3620

wood opal A variety of opal with woody texture by replacement. Syn: opalized wood; xylopal; lithoxyl. wood piling A method of sinking a shaft through loose surface deposits by driving a ring of wood piles down vertically. As the piles are rammed downward, the loose material is removed. Frames are set to prevent the piles being forced inward. Each new set of piles reduces the dimensions of the excavation. To avoid this reduction in size, the piles are driven at an angle away from the shaft space. Nelson Wood process A flotation process utilizing the surface tension of water, either fresh, acid, or salt. woodrock A variety of asbestos resembling wood. Standard, 2 woodruffite A monoclinic mineral, (Zn,Mn)Mn3 O7 .H2 O ; related to todorokite; at Sterling Hill, NJ. woodstave piping Piping formed from wood boards fitted and strapped together by encircling steel bands. Pryor, 3 wood stilt A piece of wood attached to the leg of steel girders to provide a measure of yield and prevent premature distortion and damage to the ring. See also: arch girder; stilt. Nelson woodstone See: silicified wood wood tin A nodular variety of cassiterite, or tinstone, of a brownish color and fibrous structure, and somewhat resembling dry wood in appearance. Syn: dneprovskite woodwardite 3621

A mineral, Cu42+ Al2 (SO4 )(OH)12 .2-4H2 O(?) ; greenish-blue; closely akin to cyanotrichite. Worden gravimeter A compact temperature-compensated gravity meter, in which a system is held in unstable equilibrium about an axis, so that an increase in the gravitational pull on a mass at the end of a weight arm causes a rotation opposed by a sensitive spring. The meter weighs 5 lb (2.25 kg) and has a sensitivity of less than 0.1 mgal. AGI work a. The process of mining coal. BCI b. To crumble and yield under the action of a squeeze. Applied to pillars or roof of a coal mine. c. To be slowly closing under the action of a squeeze. Applied to portions of mine workings. d. Denoting that creep or squeeze is taking place. Hudson e. The product of a force in terms of weight and the lineal distance through which it acts. Hammond f. To undergo gradual movement, such as heaving, sliding, or sinking; said of rock materials. AGI g. Ore before it is beneficiated. Fay h. A place where industrial labor of any kind is carried on. Usually in the plural as saltworks, ironworks, etc. Webster 3rd i. Objects that are to be, are being, or have been treated, such as in cleaning or finishing. ASM, 1 workable A coal seam or orebody of such thickness, grade, and depth as to make it a good prospect for development. In remote and isolated locations, other factors influence minability, such as access, water supply, transport facilities, etc. See also: economic coal reserves workable bed Any bed or vein that is capable of being mined, but usually applied to a coal seam or ore deposit that can be mined profitably. workable tonnage See: probable reserves work arm The part of a lever between the fulcrum and the working end. Nichols, 1 work capacity The limit of energy expended or absorbed, within which a body is not unduly fatigued. Brantly, 2 3622

worked out a. A mine, or large section of a mine, from which all minable coal or ore has been taken. BCI b. Exhausted; said of a coal seam or ore deposit. worker cage A special cage for raising and lowering workers in a mine shaft. See also: worker car worker car A type of car for transporting miners up and down mine shafts; also cars used to transport miners from the shaft to working areas. See also: worker cage worker door a. A small door in a stopping to allow the passage of workers. Nelson b. Scot. A small trapdoor on a traveling road. Fay worker-hoist engineer In mining, a person who operates the hoisting engine that serves the shaft in which only workers are raised from and lowered into a mine. DOT worker trip a. A trip made by mine cars and locomotives to take workers, rather than mined material or supplies, to and from the working places. BCI b. A similar trip made by a worker cage in a shaft. work index See: Bond's third theory working a. When a coal seam is being squeezed by pressure from the roof and floor it emits creaking noises and is said to be "working." This noise often serves as a warning to miners that additional support is needed. Sagging roof emitting noises and requiring additional timbering. BCI b. A working may be a shaft quarry, level, opencut, or stope, etc. Usually in the plural. See also: labor; workings. Fay working a claim

3623

Activities such as extracting ore, building structures, and otherwise developing a mining claim after ore is discovered. Ricketts working capital The amount of money available to finance the operations of a company beyond the amount required for the purchase of fixed assets, such as property. Truscott working cycle A complete set of operations. In excavation, it usually includes breaking, loading, moving, dumping, and returning to the loading point. Nichols, 1 working face The place at which mining is being done in a breast, gangway, airway, chute, heading, drift, adit, crosscut, etc. See also: face working gullet The immediate excavation needed for opencast working of ore. Nelson working-hole In glassmaking, a small opening over pots enabling workers to introduce or withdraw material required. working home Mining toward the main shaft while extracting ore or coal, such as in longwall retreating. See also: longwall working interest The operator's mineral ownership involving the costs of drilling, completion, equipment, and producing in contrast to the (free) royalty interest. Wheeler, R.R. working level (WL) Any combination of radon daughters in one liter of air that result in the ultimate emission of 1.3 X 105 million electrons volts (MeV) of alpha energy. NSC, 2 working load

3624

The maximum weight a hoist line or other rope or cable can carry under working conditions without danger of straining. Long working on air A pump is said to be working on air when air is sucked up with the water. Fay working-on-the-walls The eroding or corroding of blast furnace linings. Fay working out Mining away from the main shaft while extracting ore or coal, such as in longwall advancing. See also: advancing working pit A mine shaft through which ore and miners are carried, as distinguished from one used only in pumping. Standard, 2 working place a. A place in a mine at which coal or ore is actually being mined. See also: working face b. A miner's room or chamber. Hudson working room Generally the space between the working face and the area being backfilled. Stoces workings a. Any area of development; usually restricted in meaning to apply to breasts, etc., in contradistinction to gangways and airways. Often used in a broader sense to mean all underground developments. See also: working Fay b. The entire system of openings in a mine. Typical usage restricts the term to the area where coal, ore, or mineral is actually being mined. Nelson c. Colloquial term for an anthracite mining operation. Korson working section All areas of a coal mine from the loading point of the section to and including the working faces. FR 95 working stress 3625

a. The stress considered to be a safe maximum for a particular material under ordinary conditions. See also: yield stress; load factor. Hammond b. The maximum unit stress to which the parts of a structure are to be subjected. Zern c. See: allowable stress working the broken The extraction of coal pillars in a pillar method of mining. See also: pillar extraction; broken working; second working; robbing pillars. Nelson working the whole The driving of the narrow coal headings to form pillars in a pillar method of working. Nelson work lead a. Impure pig lead that is to be desilverized or refined. See also: base bullion b. The electrical conductor connecting the source of arc welding current to the work. Also called welding ground; ground lead. ASM, 1 workplace protection factor A measure of the protection provided in the workplace by a properly functioning respirator when correctly worn and used. NIOSH work platform A board or small platform placed at a suitable height in a drill tripod or derrick so that a worker standing on it can handle the drill rod stands. Long work shaft A shaft that is in daily use for hoisting coal, ore, or miners. See also: air shaft work stone A plate in the bottom of a blast hearth or ore hearth having a groove down its center for conducting away the molten lead. Standard, 2 work study Techniques for analyzing methods used in performing an operation and measuring the work involved. Work study fosters better use of materials, plant, and labor, thus ensuring higher productivity. See also: method study 3626

worm A spiral tool, shaped like a carpenter's wood-boring auger, with the bottom end shaped like the cutting end of a diamond point or mud bit. The tool is rotated inside a casing to loosen and clean out debris or to loosen and drill through tough clay at the bottom of a borehole. Also called worm auger; worm-type auger. Long worm auger See: worm worm conveyor a. A conveyor consisting of a spiral plate encircling and fastened to a shaft lying longitudinally within a trough; rotation of the spiral pushes the material forward. Also called screw conveyor. BS, 5 b. See: helical conveyor worm wheel A modified spur gear with curved teeth that meshes with a worm. Nichols, 1 wough The side of a mineral vein. wound rotor motor A wound rotor induction motor differs from a squirrel cage induction motor only in the construction of its rotor. The rotor, instead of having short-circuited copper bars, has a definite winding connected for the same number of poles as the stator with the leads brought out to slip rings. The stator and rotor are commonly called the primary and secondary, respectively, because under locked rotor conditions, the motor becomes a transformer with a given ratio. This ratio depends upon motor design and is not standardized. Frequently called a slip ring motor. Pit and Quarry woven-wire vibrating screen Ore screening machine whose screen is woven of steel wire and stretched tightly on a metal frame. Near the center of the screen is fastened the vibrating element of a highspeed vibrator, which produces a vibratory motion at right angles to the plane of the screen. Newton, 1 WP-cut

3627

A tunnel blasting method in which holes are arranged in a geometrical figure as an incomplete pyramid and not parallel in the planes of the sides. For tunnel widths less than 25 ft (7.5 m), the WP-cut provides a greater advance than V-cuts and fan cuts. wracking force A horizontal force tending to distort a rectangular shape into a parallelogram. Hammond wrap-drive conveyor A conveyor in which the return strand of the belt is driven by a wrap drive which combines a drive pulley with a snub pulley. NEMA, 2 wrap-up Same as windup, as applied to the twist in a drill-rod string. See also: windup wreath In glassmaking, a wavy appearance in glass, esp. flint glass, due to defective manufacture. Standard, 2 wrecking bar A steel bar usually from 1 to 2 ft (0.3 to 0.6 m) in length, with one end drawn to a thin edge, the other curved to a claw. Crispin wrench fault A transverse strike-slip fault that is more or less vertical. wrist action In a bucket, the ability to change its digging or dumping angle by power. Nichols, 1 wrought alloy Type of alloy suitable for forming by mechanical means at temperatures below the melting point. Light Metal Age wrought iron a. A low-carbon iron containing a relatively high proportion of residual slag that gives it ductility and toughness. Strock, 2 b. A commercial form of iron containing less than 0.3%, and usually less than 0.1%, carbon; also carrying 1.0% or 2.0% of slag 3628

mechanically mixed with it and originally made directly from ore (as in the Catalan forge) but subsequently by puddling. See also: iron Webster 3rd wrought metal A metal that has been worked by cold rolling, forging, pressing, drawing, or extension. Hammond Wuensch process In metallurgy, a heavy suspension method for the concentration of ores in which the waste has a specific gravity of 2.7 or more. Minerals having a specific gravity in excess of 5.25 must be used, since a suspension containing over 40% solids by volume is too plastic for use. Galena (sp gr, 7.4 to 7.6) and ferrosilicon (sp gr, 6.7 to 7.0) have been used. Hess wulfenite A tetragonal mineral, PbMoO4 ; prismatic cleavage; soft; resinous; yellow to brown; sp gr, 6.5 to 7.0; in oxidized zones of lead-molybdenum veins; a source of molybdenum. Syn: yellow lead ore wurtzilite A black, massive, asphaltic pyrobitumen; sectile and infusible; closely related to uintahite; insoluble in turpentine; derived from metamorphosed petroleum; occurs in veins in Uinta County, UT. See also: elaterite wurtzite A trigonal and hexagonal mineral, (Zn,Fe)S ; dimorphous with sphalerite; resinous; brownish black; forms hemimorphic pyramidal crystals or radiating needles and bundles within lamellar sphalerite. See also: alpha zinc sulfide; zinc sulfide. wurtzite-8H; wurtzite-10H Two polytypes, 8ZnS and 10ZnS, respectively, of wurtzite found at Joplin, MO; hexagonal. The wurtzite polytypes evidently form a homologous series (2H, 4H, 6H, etc.) resulting from growth phenomena based on screw dislocations. Am. Mineral., 1 wuestite A mineral, FeO. Artificially prepared specimens are characteristically deficient in iron. Also spelled wustite. Syn: iozite 3629

wyartite An orthorhombic mineral, Ca3 U(UO2 )6 (CO3 )2 (OH)18 .3-5) H2 O ; violet-black; occurs with ianthinite altered from uraninite; at Shinkolobwe, Katanga, Republic of the Congo. wych See: wich wye a. Cumb. The beam-end connection above the pump rods of a winding and pumping engine. Fay b. A cast or wrought fitting that has one side outlet at any angle other than 90 degrees . The angle is usually 45 degrees , unless another angle is specified. The fitting is usually indicated by the letter Y. Strock, 1 Wyoming bentonite A swelling type of bentonite that absorbs about eight times its dry volume of water to form a gel. See also: bentonite

X xalostocite A rose-pink variety of grossularite garnet. Also called rosolite; landerite. From Xalostoc, Morelos, Mex. English xanthate Common specific promoter used in flotation of sulfide ores. A salt or ester of xanthic acid made of an alcohol, carbon disulfide, and an alkali. xanthiosite A monoclinic mineral, Ni3 (AsO4 )2 ; sulfur-yellow. xanthitane a. An alteration product of titanite (sphene). b. See: anatase xanthochroite 3630

Amorphous cadmium sulfide. See also: greenockite xanthoconite A monoclinic mineral, Ag3 AsS3 ; dimorphous with proustite; brilliant red, orange-yellow to brown. Syn: rittingerite xanthophyllite See: clintonite xanthorthite A yellow altered variety of allanite that contains considerable water. Standard, 2 xanthoxenite A triclinic mineral, Ca4 Fe2 (PO4 )4 (OH)2 .3H2 O ; wax-yellow; forms thin plates; at Rabenstein, Bavaria, Germany. xanthus An early name for heliotrope. Hey, 3 x-axis a. The axis of abscissas in a plane Cartesian coordinate system. Commonly written xaxis. (Webster 3rd, 1966) b. One of the three optic axes (x, y, and z) in a biaxial crystal. The x-axis is the axis of a greatest ease of vibration. Light vibrating parallel to the x-axis travels with maximum velocity and is called the fast ray, the x-ray (not to be confused with the penetrating X-rays of extremely short wavelength), and the alpha -ray. The lowest index of refraction nalpha . in biaxial minerals is the index of the fast ray vibrating parallel to the x-axis. c. One of three axes in a three-dimensional coordinate system. Crystallographers customarily use a right-handed system with the z-axis oriented positive upward, the y-axis positive to the right, and the x-axis positive toward the viewer. For mineral parameters the x-axis is labeled a with periodic translations t1 . x-coordinate a. An abscissa in a plane Cartesian coordinate system. Webster 3rd b. One of the three coordinates in a three-dimensional rectangular coordinate system. Webster 3rd x-direction

3631

One of three orthogonal optic directions in biaxial crystals. Light with its electric vector (vibration direction in early terminology) parallel to the x-direction has the lowest refractive index (nalpha ) for a given crystal and is called the fast ray. In orthorhombic crystals, the x-axis is constrained by symmetry to correspond to one of the crystallographic directions, the correspondence determined empirically. In monoclinic crystals, one optic direction, commonly the y-direction, is constrained by symmetry to correspond to the unique diad. In triclinic crystals, there is no symmetrical constraint relating optic directions to crystallographic axes. xenoA prefix meaning strange or foreign. xenoblast A crystal that has grown during metamorphism without the development of its characteristic faces. CF: idioblast xenoblastic Applied to a texture of metamorphic rocks in which the constituent mineral grains lack proper crystal faces. xenocryst A crystal in an igneous rock that is foreign to the body of rock in which it occurs. CF: xenolith xenogenous A little-used syn. of epigenetic. AGI xenolite A silicate of aluminum, related to fibrolite. Fay xenolith A foreign inclusion in an igneous rock. CF: autolith; xenocryst. Syn: inclusion; exogenous inclusion; accidental inclusion. AGI xenomorphic a. Said of the holocrystalline texture of an igneous or metamorphic rock, characterized by crystals not bounded by their own faces but with their forms impressed upon them by 3632

adjacent mineral grains. Also said of a rock with such a texture. AGI b. (Syn: anhedral in European usage.) Syn: allotriomorphic; anidiomorphic; xenomorphic-granular. CF: automorphic. AGI xenomorphic-granular See: xenomorphic xenon A zero-valent, very heavy, inert gaseous element; one of the so-called noble gases. Symbol, Xe. Obtained by the fractional distillation of liquid air. The gas is used in making electron tubes, stroboscopic lamps, and bactericidal lamps; also used in the atomic energy field in bubble chambers, probes, and other applications where its high molecular weight is of value. Handbook of Chemistry and Physics, 3 xenothermal Said of a hydrothermal mineral deposit formed at high temperature but shallow depth; also, said of that environment. CF: telethermal; epithermal; mesothermal; hypothermal deposit; leptothermal. AGI xenotime A tetragonal mineral, YPO4 ; commonly includes small quantities of thorium, uranium, and rare-earth elements; resembles zircon in form, structure, and occurrence; shows pale tints; an accessory in granites and pegmatites; also occurs in placers. X-frame brace A brace of a square set in which two diagonal pieces of timber cross to form an X. Fay xonotlite A monoclinic and triclinic mineral, Ca6 Si6 O17 (OH)2 ; light-gray to pink; fibrous; in serpentinites in Santa Barbara, CA, and on Isle Royale, MI. X-ray diffraction Reflection at definite and characteristic angles from space lattices of crystals of X-rays that have been caused to bombard them, thus giving data for identification of characteristic lattice structure of a given species of mineral. See also: reciprocal lattice; diffraction. Pryor, 3 xylain 3633

a. A subvariety of provitrain in which the woody origin of the cellular structure is microscopically visible. CF: periblain; suberain. AGI b. Those constituents of coal derived from lignified tissues in which structures were retained. AGI xylanthite A variety of fossil resin. Tomkeieff xylenite A maceral composed of xylain. Tomkeieff xylinite a. A variety of provitrinite. The micropetrological constituent, or maceral, of xylain. It consists of wood (xylem or lignified tissues) almost jellified in bulk but still showing faint traces of cell walls and resin contents under the microcope. AGI b. A distinction of telinite, based on botanical origin (xylem or lignified tissues). To be used if desired but considered unnecessary by the Heerlen Congress of 1935. CF: suberinite; telinite. AGI xylocryptite See: scheererite xyloidin An explosive compound produced by the action of nitric acid on starch or woody fiber. Resembles guncotton. Fay xylopal See: wood opal xyloretinite A white hydrocarbon similar to hartite found in fossil wood. Tomkeieff

Y YAG Acronym and abbrev. for yttrium-aluminum garnet. USBM, 7 3634

yard The British standard of length, equal to 36 in, 3 ft, or 0.9144 m. Hammond yardage a. The extra compensation a miner receives in addition to the mining price for working in a narrow place or in deficient coal. Usually at a certain price per yard (or meter) advanced. b. A system of payment to workers in accordance with the number of yards (or meters) driven, repaired, or packed; the length in yards (or meters) of a drivage or face which a miner or contractor has excavated in a week or from one measuring day to the next. Also called yard work. See also: piecework c. Relates to cubic yards (or meters) of earth excavated. Crispin d. Price paid per yard (or meter) for mining or cutting coal, usually by contract agreement, not on a tonnage basis. BCI yardage man In bituminous coal mining, a laborer who pries down loose roof rock with a bar after coal has been blasted from the working face; the worker picks out seam partings (layers of rock) in the coal working face prior to blasting, using a long handled pick. DOT yard price The price paid per yard driven (in addition to tonnage prices) for roads of certain widths and driven in certain directions. See also: yardage. Fay yard work See: yardage yavapaiite A monoclinic mineral, KFe(SO4 )2 ; at the United Verde copper mine, Jerome, AZ. Named for the local Yavapai Native Americans. y-axis a. One of the three optic axes (x,y, and z) in a biaxial crystal. The y-axis is the intermediate optic axis, at right angles to the plane containing optic axes x and z. Light vibrating parallel to the y-axis is called the intermediate ray, the y-ray, and the beta -ray. The middle-value index of refraction nbeta in biaxial minerals is the index of the intermediate ray vibrating parallel to the y-axis. b. One of three axes in a threedimensional coordinate system. Crystallographers customarily use a right-handed system with the z-axis oriented positive upward, the y-axis positive to the right, and the x-axis positive toward the viewer. For mineral parameters, the y-axis is labelled b with periodic 3635

translations t2 . In monoclinic crystal systems, mineralogists conventionally adopt the second setting and designate the unique diad y. y-coordinate a. An ordinate in a plane Cartesian coordinate system. Webster 3rd b. One of the three coordinates in a three-dimensional rectangular coordinate system. Webster 3rd y-direction a. One of three orthogonal optic directions in biaxial crystals. Light with its electric vector (vibration direction in early terminology) parallel to the y-direction has a unique intermediate refractive index (nbeta ) for a given crystal and is called the fast ray, relative to light with its electric vector parallel to the z-direction, and the slow ray, relative to light with its electric vector parallel to the x-direction. In orthorhombic crystals, the ydirection is constrained by symmetry to correspond to one of the crystallographic directions, the correspondence determined being empirically. In monoclinic crystals, one optic direction, commonly the y-direction, is constrained by symmetry to correspond to the unique diad. In triclinic crystals, there is no symmetrical constraint relating optic directions to crystallographic axes. b. One of three orthogonal optic directions in biaxial crystals. Light with its electric vector (vibration direction) parallel to the y-direction has a unique intermediate index of refraction (nbeta ) for a given crystal and is fast or slow depending on crystal orientation. yeast Fungi belonging to the ascomycetes, in which the usual and dominant growth form is unicellular. Rogoff yeatmanite A triclinic mineral, Mn9 Zn6 Sb2 Si4 O28 ; forms brown crystals; at Franklin Furnace, NJ. yellow antimony a. Yellow allotropic form of antimony. Obtained by oxidizing antimony hydride at a low temperature. Bennett b. An unstable form of antimony. It can be obtained during the electrolysis of antimony trichloride, SbCl. As yellow antimony (alpha antimony) is deposited on an electrode, it forms a solid solution in the antimony chloride. When this solution is scratched or heated, metallic antimony (beta antimony) and clouds of antimony chloride form instantaneously, giving rise to the term explosive antimony. There are four allotropic forms of antimony: yellow antimony; black antimony; explosive antimony; and metallic antimony or ordinary antimony. These allotropic forms are also designated alpha antimony (yellow antimony); beta antimony (metallic antimony); and gamma antimony. CCD, 2; Handbook of Chemistry and Physics, 2 3636

yellow arsenic See: orpiment yellow boy Deposit from the acid waters of a mine or partial neutralization. Ferrous anhydride and other impurities including fine clay carried down with it. Zern yellow cake a. Applied to certain uranium concentrates produced by mills. It is the final precipitate formed in the milling process. Usually considered to be ammonium diuranate or sodium diuranate, but the composition is variable and depends on the precipitating conditions. USBM, 7 b. A common form of triuranium octoxide, the powder obtained by evaporating an amnonia solution of the oxide. CCD, 2 yellow coal See: tasmanite yellow copper See: chalcopyrite yellow copperas See: copiapite yellow copper ore See: chalcopyrite yellow dog Field name for a drill tripod or derrick lamp, consisting of a metal container with two spouts holding cotton wicks, on which burning oil gives a very yellow light. Long yellow earth a. Impure yellow ocher. Webster 3rd b. Loess of northern China. yellow gravel Eng. The lower subdivision of the Aptian sponge gravel; Faringdon, Berkshire. Arkell 3637

yellow ground Oxidized kimberlite of yellowish color found at the surface of diamond pipes (e.g., South Africa), above the zone of blue ground. AGI yellow heat A division of the color scale. generally given as about 2,000 degrees F (1,090 degrees C). yellow lead ore See: wulfenite yellow ocher a. A mixture of limonite usually with clay and silica. Used as a pigment. Webster 3rd b. A moderate orange yellow that is yellower and darker than deep chrome yellow. Webster 3rd c. See: goethite; limonite. yellow ore See: carnotite; chalcopyrite. yellow ozokerine A product resembling vaseline, but less homogeneous; produced from crude ozokerite. Fay yellow pyrite See: chalcopyrite yellow ratsbane See: orpiment yellow sands Eng. The basal part of the Permian, Durham. Arkell yellow tellurium See: sylvanite yenite 3638

A rejected syn. for ilvaite. CTD yield a. The proportion of coal or ore obtained in mining; the product of a metallurgical process; extraction; recovery. Fay b. The percentage of "run-of-mine" material that is marketable. Hudson c. The amount of a product obtained from any operation expressed as a percentage of the feed material. BS, 5 yielding arch Steel arch installed in an underground mine. Arches are employed to support loads caused by changing ground movement or faulted and fractured rock. They are designed so that when the ground load exceeds the design load of the arch as installed, yielding takes place in the joint of the arch, permitting the overburden to settle into a natural arch of its own, thus tending to bring all forces into equilibrium. Lewis yielding floor A soft floor that heaves and flows into open spaces when subjected to heavy pressure from packs or pillars. See also: creep yielding prop An adjustable steel prop that incorporates a sliding or flexible joint that comes into operation when roof pressure exceeds a set load or value. See also: hydraulic chock; hydraulic prop. Nelson yielding support A support that incorporates a sliding or flexible joint or stilt to accommodate early pressure and thus delays damage and distortion of the support. Friction or hydraulic devices may be used so that a support, when subjected to a load above its set load, yields mechanically rather than by distorting. See also: stilt yield loss The difference between the actual yield of a product and the yield theoretically possible (based on the reconstituted feed) of a product with the same properties (usually percentage of ash). Also called washing error. BS, 5 yield-pillar system A method of roof control whereby the natural strength of the roof strata is maintained by relieving pressure in working areas and controlling transference of load to abutments that 3639

are clear of workings and roadways. The method consists of causing certain coal pillars to yield in small amounts. See also: double packing yield point The differential stress at which permanent deformation first occurs in a material. Syn: yield stress; yield strength. Roark yield strength The stress at which a material exhibits a specified deviation from proportionality of stress and strain. An offset of 0.2% is used for many metals. See also: yield point yield stress a. The lowest stress at which extension of a tensile test piece increases without increase in load. It is determined by observing the fall of the testing lever and checked by a pair of dividers on the original gage length. Many materials do not indicate a defined yield stress and in such cases the proof stress is used. See also: working stress; high-tensile steel; mild steel; yield point. Hammond b. Minimum stress required to shear (that is, exceed elastic recovery) a suspension, such as the dense media used in mineral concentration. Pryor, 3 YIG Acronym and abbrev. for yttrium-iron garnet. USBM, 7 yoderite A monoclinic mineral, (Mg,Al)8 Si4 (O,OH)20 ; purple; highly pleochroic; in a quartzyoderite-kyanite-talc schist at Mautia Hill, Kongwa, Tanzania. Yogo sapphire Dark-blue corundum from Yogo Gulch, MT. Schaller yoke a. An interconnecting link between the twin cylinders of a hydraulic-feed diamond drill through which the action of the hydraulic-feed cylinders is transmitted to the drill rods and bit. Long b. A clamp fitted to the casing at the collar of a drill hole, which when anchored by means of wedge bolts prevents grout pressure from forcing the casing out of the hole. Long yolk 3640

Nodule; occurs at Forest of Dean, U.K. Yorkian A term which has been proposed (instead of Westphalian) for the Coal Measures strata between the Lanarkian and the Staffordian. Nelson yoshimuraite A triclinic mineral, (Ba,Sr)2 TiMn2 (SiO4 )2 (PO4 ,SO4 )(OH,Cl) ; forms orange-brown tabular crystals or stellate groups; occurs in an alkali pegmatite at the Noda-Tamagawa Mine, Iwate prefecture, and the Taguchi Mine, Aichi Prefecture, Japan. yowah nut Walnut-to almond-size pebble with an opal center; ironstone covered with a thin band of opal, or hollow; near Yowah station, western Queensland, Australia. A subvariety of boulder opal. ytterbite See: gadolinite ytterbium A rare-earth element that has a bright silvery luster, is soft, malleable and quite ductile. Symbol, Yb. Occurs with other rare-earths in a number of rare minerals. Commercially recovered from monazite sand. Has a possible use in improving the mechanical properties of stainless steel; few other uses have been found. Handbook of Chemistry and Physics, 3 yttergranat A calcium-iron garnet containing a small amount of yttria. A variety of andradite. Fay yttrialite A possibly hexagonal mineral, (Y,Th)2 Si2 O7 ; olive green tarnishing to orange-yellow; occurs in Texas. yttrium A rare-earth element that has a silvery-metallic luster. Symbol, Y. Occurs in nearly all of the rare-earth minerals. Recovered commercially from monazite sand and from bastnasite. Widely used: in color television tubes; to reduce the grain size in chromium, molybdenum, zirconium, and titanium; to increase the strength of aluminum and 3641

magnesium alloys; as a deoxidizer for vanadium and other nonferrous metals; in nuclear technology for its high neutron transparency. Handbook of Chemistry and Physics, 3 yttrium-aluminum garnet Synthetic; Y3 Al5 O12 ; has useful magnetic properties. Actually not a true garnet and should not be confused with any of the silicate minerals called garnets in the garnet group of minerals. Manufacture of yttrium-aluminum garnets is a commercial use of yttrium. Used in lasers and in microwaves and other electronic applications. Acronym and abbrev., yag. Handbook of Chemistry and Physics, 2 yttrium garnet A variety of garnet containing a small amount of yttrium earths. Syn: yttrogarnet yttrium-iron garnet Synthetic; Y3 Fe5 O12 ; has useful magnetic properties. Actually not a true garnet and should not be confused with any of the silicate minerals called garnets in the garnet group of minerals. Manufacture of yttrium-iron garnets is a leading commercial use of yttrium. Used as electronic transmitters, as filters for selecting or tuning microwaves, and as transmitters and transducers of acoustic energy. Acronym and abbrev., yig. Bennett; CCD, 2; Handbook of Chemistry and Physics, 2 yttrocrasite An orthorhombic mineral, (Y,Th,Ca,U)(Ti,Fe)2 (O,OH)6 ; also contains Th, U, Fe; radioactive; black altering to a dull brown coating; in granite pegmatites. yttrogarnet See: yttrium garnet yttromicrolite A discredited mineral name for an amorphous mixture of calcium sulfate, tantalite, and heterogeneous microlite. yttro-orthite See: allanite yttrotantalite

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An orthorhombic mineral, (Y,U,Fe) (Ta,Nb)O4 ; radioactive; black to brown: in pegmatites. yttrotungstite A monoclinic mineral, YW2 O6 (OH)3 . Syn: thorotungstite yugawaralite A monoclinic mineral, CaAl2 Si6 O16 .4H2 O ; zeolite group; colorless to white; in lowgrade metamorphosed tuffs near the Yugawara hot spring, Kanagawa, Japan. yukonite a. A noncrystalline mineral: Ca2 Fe3 (AsO4 )4 OH.12H2 O. AGI b. An obsolete term originally assigned to an igneous rock intermediate in composition between a tonalite and an aplite. It is named after the Yukon River, Alaska. AGI

Z zaffer Mixed arsenates and oxides of cobalt produced by roasting sulfide ores. Pryor, 3 zanthochroite Amorphous cadmium sulfide; greenockite is the crystalline form. Am. Mineral., 1 zaratite An isometric mineral, Ni3 (CO3 )(OH)4 .4H2 O ; emerald green; forms incrustations and compact masses in mafic and ultramafic rocks. zarnec See: zarnich zarnich Native sulfide of arsenic, including sandarac and orpiment. Syn: zarnec. Webster 2nd zavaritskite 3643

A tetragonal mineral, BiOF ; at Sherlova Gory, East Transbaikal, Russia. z-axis a. One of the three optic axis (x, y, and z) in a biaxial crystal. The z-axis is the axis of least ease of vibration. Light vibrating parallel to the z-axis travels with minimum velocity and is called the slow ray, the z-ray, and the gamma -ray. The highest index of refraction ngamma , in biaxial minerals is the index of the slow ray vibrating parallel to the z-axis. b. One of three axes in a three-dimensional coordinate system. Crystallographers customarily use a right-handed system with the z-axis oriented positive upward, the yaxis positive to the right, and the x-axis positive toward the viewer. For mineral parameters, the z-axis is labelled c with periodic translations t3 . If one crystallographic axis is symmetrically unique, it is labelled z, except in the monoclinic system, where mineralogic convention uses the second setting labelling the unique diad y. z-coordinate One of the three coordinates in a three-dimensional rectangular coordinate system. Webster 3rd z-direction One of three orthogonal optic directions in biaxial crystals. Light with its electric vector (vibration direction in early terminology) parallel to the z-direction has the highest refractive index (ngamma ) for a given crystal and is called the slow ray. In orthorhombic crystals, the z-direction is constrained by symmetry to correspond to one of the crystallographic directions, the correspondence determined empirically. In monoclinic crystals, one optic direction, commonly the y-direction, is constrained by symmetry to correspond to the unique diad. In triclinic crystals, there is no symmetrical constraint relating optic directions to crystallographic axes. zeasite Wood opal, formerly a name for fire opal. zebra dolomite A term used in the Leadville district of Colorado for an altered dolomite rock that shows conspicuous banding (generally parallel to bedding) consisting of light-gray coarsely textured layers alternating with darker finely textured layers. See also: zebra rock zebra rock a. A term used in the Colville district of NE Washington State for a dolomite that shows narrow banding consisting of black layers (indicative of organic matter) alternating with 3644

white, slightly coarse-grained, and somewhat vuggy layers. See also: zebra dolomite b. A term used in Western Australia for a banded quartzose rock of Cambrian age. AGI Zeiss konimeter A portable dust-sampling instrument. See also: konimeter Zellweger furnace A long-hearth reverberatory furnace used at Iola, KS. Fay Zemorrian Lower Lower Miocene. AGI zeolite A generic term for class of hydrated silicates of aluminum and either sodium or calcium or both, of the type Na2 O.Al2 O3 .nSiO2 .xH2 O . The term originally described a group of naturally occurring minerals. The natural zeolites are analcite, chabazite, heulandite, natrolite, stilbite, and thomsonite. Artificial zeolites are made in a variety of forms, ranging from gelatinous to porous and sandlike, and are used as gas adsorbents and drying agents as well as water softeners. Both natural and artificial zeolites are used extensively for water softening. The term zeolite now includes such diverse groups of compounds as sulfonated organics or basic resins, which act in a similar manner to effect either cation or anion exchange. CCD, 2 zeolite mimetics The dachiardite group of zeolites. zeolite process a. A base exchange method of treating hard water, in which zeolites, contained in a tank, remove salts. The zeolite layer is regenerated by backflushing with brine. Nelson b. See: base exchange zeolitic deposit A deposit, particularly of native copper, that occurs in basalt accompanied by minerals of the zeolite group. zeolitization

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Introduction of, alteration to, or replacement by, a mineral or minerals of the zeolite group. This process occurs chiefly in rocks containing calcic feldspars or feldspathoids, and is sometimes associated with copper mineralization. AGI zeophyllite A triclinic mineral, Ca4 Si3 O8 (OH,F)4 .2H2 O ; pseudohexagonal; forms white spherical, radiated folia; at Cross-Preisen, Bohemia, Czech Republic. zero air voids curve The curve showing the zero air voids unit weight as a function of water content. Syn: saturation curve zero air voids unit weight The weight of solids per unit volume of a saturated soil mass. See also: unit weight zero-length spring Special type of gravimeter spring for which the length is proportional to the applied force. Schieferdecker zero-point energy The kinetic energy remaining in a substance at a temperature of absolute zero. Webster 3rd zero potential The actual potential at the surface of the Earth taken as a point of reference. Webster 3rd zero time When conducting a mine ventilation pressure survey, zero time is the time of the commencement of the survey from the base station, and the reading of the control barometer there is taken as the pressure datum to which subsequent pressures are referred. Sinclair, 1 zero-zero gel A condition wherein a drilling fluid fails to form measurable gels during a quiescent 10min time interval. Brantly, 1 zeta potential 3646

The potential difference across an electric double layer, usually between a solid surface and a liquid. Syn: electrokinetic potential See also: surface zeta-potential layer The zone of shear surrounding a particle immersed in an electrolyte. Pryor, 4 zeunerite A tetragonal mineral, Cu(UO2 )2 (AsO4 )2 .10H2 O ; autunite group. zeylanite See: ceylonite zhemchuzhnikovite A trigonal mineral, NaMg(Al,Fe)(C2 O4 ).8H2 O ; an oxalate occuring in green crystals that appear violet in artificial light; in veinlets in coal in the Chaitumusuk deposits, Siberia, Russia. Ziervogel process The extraction of silver from sulfide ores or matte by roasting in such a way as to form sulfate of silver, leaching this out with hot water, and precipitating the silver by means of metallic copper. Fay zietrisikite Incorrect spelling of pietricikite, a waxlike hydrocarbon similar to ozokerite. Tomkeieff zigzag car loader A form of vertical chute in which the chute is divided into independent sections that can be raised or lowered on a track arrangement. It is flexible and can be lowered to the bottom of the car, giving a solid stream of coal from loading pocket to car. Mitchell zigzag fold See: chevron fold zigzag rule A wooden rule (generally 2 m or 6 ft long, folded zigzag fashion in 15-cm or 6-in lengths), used by drillers, craftsmen, etc., to measure short distances. The rule usually is 3647

graduated in centimeters or in feet, inches, and fractions of an inch (sometimes in feet, tenths of a foot, and hundredths of a foot). Long zigzag transformer A zigzag transformer is a transformer intended primarily to provide a neutral point for grounding purposes. Syn: grounding transformer. USBM, 2 ziment water Water impregnated with copper; found in copper mines. Standard, 2 Zimmermann's rule A graphical method for finding the lost part of a vein on the other side of a fault. Nelson zinc a. The native metallic element, Zn. b. A bluish-white, lustrous metal. Employed to form numerous alloys with other metals including brass, nickel silver, commercial bronze, spring brass, soft solder, and aluminum solder. Used extensively by the automotive, electrical, and hardware industries. Handbook of Chemistry and Physics, 3 zincaluminite A light-blue mineral, Zn6 Al6 (SO4 )2 (OH)26 .5H2 O . zinc blende See: sphalerite zinc bloom See: hydrozincite; zinc oxide. zinc box Wooden or enamel-ware rectangular box, with a bottom grid that supports zinc shavings. Used in the cyanide process to precipitate dissolved gold from a pregnant solution. Its place was taken by use of zinc dust. See also: Merrill-Crowe Process zinc carbonate White; ZnCO3 ; soluble in acids, in alkalies, and in ammonium salt solutions; insoluble in water; and dissociates losing carbon dioxide at 300 degrees C. Used in ceramics and as a 3648

pigment. Also used less accurately to refer to any of several basic carbonates of zinc, which include the zinc-ore mineral hydrozincite, Zn5 (CO3 )2 (OH)6 or Zn5 (OH)6 (CO3 )2 and synthetically prepared pigments of the same or similar composition. Syn: smithsonite; calamine; zinc spar. Handbook of Chemistry and Physics, 2 zinc chloride White; hexagonal; ZnCl2 ; poisonous. Obtained by the solution of zinc, or zinc oxide, in hydrochloric acid, or by burning zinc in chlorine. Used in galvanizing iron, as a catalyst, as a dehydrating agent, as a condensing agent, as a wood preservative, as an ingredient in soldering fluxes, in burnishing and polishing compounds for steel, in electroplating, in glass-etching compositions, in petroleum refining, and in pigments. Handbook of Chemistry and Physics, 2 zinc chromate ZnCrO4 ; a golden-yellow pigment. Of variable composition; the chemically pure zinc chromate, a yellow crystalline powder is said to be zinc chromate heptahydrate, ZnCrO4 .7H2 O . Called zinc yellow, but this term is also applied to hydrated zinc chromate and to hydrated zinc-potassium chromate. Another zinc chromate is dark green to black and has a different composition; isometric. ZnCr2 O4 . Syn: zinc chrome; zinc yellow. Handbook of Chemistry and Physics, 2 zinc chrome See: zinc chromate; zinc yellow. zinc dust Finely divided zinc that usually contains small amounts of zinc oxide and impurities. Also called powdered zinc; zinc gray. Fay zinc gray See: zinc dust zinc hydrosulfite White; amorphous; ZnS2 O4 ; and soluble in water. Used as a depressant in flotation. CCD, 2 zincite

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A red to yellow brittle mineral; (Zn,Mn)O. It is an ore of zinc, as in New Jersey where it is associated with franklinite and willemite. Syn: red zinc ore; red zinc oxide; ruby zinc; spartalite. AGI zinckenite See: zinkenite zinckiferous Carrying zinc. Weed, 2 zinc-magnesia chalcanthite A variant of chalcanthite with the formula, (Cu,Zn,Mg)SO4 .5H2 O . Hey, 1 zinc melanterite A member of the monoclinic melanterite group, in which iron is partially replaced by zinc. English zinc-melanterite A monoclinic mineral, (Zn,Cu,Fe)SO4 .7H2 O . zinc minerals The principal ore is sphalerite, ZnS ; other important ore minerals are smithsonite, ZnCO3 ; hemimorphite, Zn4 Si2 O7 (OH)2 .H2 O ; franklinite, (Zn,Mn,Fe)(Mn,Fe)2 O4 ; willemite, Zn2 SiO4 ; and zincite, ZnO . zinc oxide White or yellowish-white; white turns yellow on heating; ZnO; odorless; absorbs carbon dioxide from the air; used in pigments, ceramic glazes, and opaque glass and in the manufacture of magnetic ferrites and specialized ceramics. Zinc oxide is a common constituent in high-grade fluoride opal glass, in tank-window glass, and in some optical glass. Commonly used in dry-process, cast-iron enamels. Syn: zincite; zinc bloom; zinc white. Handbook of Chemistry and Physics, 2 zincrosasite A monoclinic mineral, (Zn,Cu)(CO3 )(OH)2 ; rosasite group; at Tsumeb, Namibia. zinc scum 3650

The zinc-silver alloy skimmed from the surface of the bath in the process of desilverization of lead by zinc. Fay zincsilite A monoclinic mineral, Zn3 Si4 O10 (OH)2 .4H2 O(?) ; smectite group; in Batystau, Kazakhstan. zinc spar See: smithsonite; zinc carbonate. zinc spinel See: gahnite zinc sulfate Orthorhombic ZnSO4 ; used in flotation. zinc sulfate heptahydrate Colorless; needles; ZnSO4 .7H2 O ; odorless; astringent, metallic taste; effloresces in air; sp gr, 1.9661; melting point, 50 degrees C if heated rapidly; soluble in water and in glycerol; insoluble in alcohol; and its solutions are acid to litmus. Used in preparing zinc chemicals. Orthorhombic; molecular weight, 287.54; sp gr, 1.957 (at 25 degrees C, referred to water at 4 degrees C) and ranges from 1.9 to 2.1; Mohs hardness, 2.0 to 2.5; melting point, 100 degrees C; loses 7H2 O on heating to 280 degrees C; and slightly soluble in alcohol and in glycerol. Occurs as the mineral goslarite, which is white or yellowish; formed by the oxidation of sphalerite (ZnS) in damp locations, esp. in the presence of iron sulfides. CCD, 2; Handbook of Chemistry and Physics, 2 zinc sulfide a. Alpha zinc sulfide is the hexagonal mineral wurtzite. See also: alpha zinc sulfide; wurtzite. b. Beta zinc sulfide is the isometric mineral sphalerite. See also: beta zinc sulfide zinc sulfide monhydrate Colorless, white, or yellowish; crystalline; ZnSO4 .H2 O ; molecular weight, 115.45; sp gr, 3.98; melting point, 1,049 degrees C; insoluble in water; and soluble in acids. Used as a pigment and in white glass and in opaque glass. Handbook of Chemistry and Physics, 2; CCD, 2 3651

zinc vitriol See: goslarite zinc white Used as a pigment. It is the whitest of all pigments; permanent, not poisonous, but lacks the opacity and covering power of white lead or titanium dioxide. See also: zinc oxide zinc yellow A greenish-yellow pigment. See also: zinc chromate. Webster 3rd zinkazurite A mineral found in small, blue crystals; probably a mixture of sulfate of zinc and carbonate of copper. Fay zinkenite A hexagonal mineral, Pb9 Sb22 S42 ; in steel-gray crystals or exceptionally thin folia in fibrous masses. Also spelled zinckenite. Syn: keeleyite zinkite See: zincite zinkosite Orthorhombic ZnSO4 . zinn Native tin. Syn: gediegen zinnwaldite A monoclinic mineral, KLiFeAl(AlSi3 )O10 (F,OH)2 ; mica group; basal cleavage; pale violet, yellowish or grayish brown; in granites, pegmatites, and greisens. zippeite An orthorhombic mineral, K4 (UO2 )6 (SO4 )3 (OH)10 .4H2 O ; radioactive; orange-yellow to bright yellow; an alteration product of uraninite occuring with gypsum, uranopilite, and limonite. Formerly called dauberite. 3652

Zipper Trade term for a conveyor belt lacing or fastening appliance, which can be applied to any thickness and width of belt. A lever mechanism is used to supply the pressure. The appliance is totally enclosed and grease-filled to protect against dust and damage. Nelson zircon A tetragonal mineral, ZrSiO4 ; occurs widely in granite, granite pegmatite, other felsic igneous rocks, and placers; the chief source of zirconium; a refractory; if cut and polished, the colorless varieties provide exceptionally brilliant gemstones. Syn: azorite; zirconite; hyacinth; jacinth. zircon flour Finely milled zircon sand. CCD, 2 zircon group Zircon, along with rutile, ilmenite, and monazite, constitutes a group of heavy minerals that are usually considered together because of their occurrence as black sands in natural beach and dune concentrations. For marketing, complete separation of the rutile and zircon as high-grade products is necessary. Separation is effected by combinations of electromagnetic and electrostatic processes, together with gravity concentration. zirconia brick Brick containing zirconium oxide; used in metallurgical furnaces. Bennett zirconiferous a. Containing zircon or yielding zircon. Webster 3rd b. Containing zirconium or yielding zirconium. Webster 3rd zirconite A gray or brownish variety of zircon. zirconium A grayish-white lustrous metallic element. Symbol, Zr. Occurs widely, but only in combined form, esp. in the minerals zircon, (ZrSiO4 ), and baddeleyite, (ZrO2 ). Uses include resisting corrosion, as a structural material in nuclear reactors, as an alloying agent, deoxidizer, bonding agent, refractory material, and in low-temperature superconductive magnets. Handbook of Chemistry and Physics, 3 3653

zirconium minerals Principal ore minerals are zircon and baddeleyite. Main uses are as refractories, ceramics, opacifiers, abrasives, enamels, insulators, and alloys. They are also a source of hafnium. Transparent zircon is a gemstone. zirconium phosphate Normal zirconium phosphate, ZrP2 O7 , has a reversible inversion at 300 degrees C and at 1,550 degrees C dissociates into zirconyl phosphate, (ZrO)2 P2 O7 , with loss of P2 O5 as vapor. Zirconyl phosphate is stable up to about 1,600 degrees C and has a very low thermal expansion--1 x 10-6 (20 to 1,000 degrees C). Dodd zirconium silicate ZrSiO4 , natural silicate of zirconium found in Brazil and elsewhere. One such deposit known as brazilite is said to contain about 80% zirconium oxide in a semimanufactured form. This product is employed as a refractory in the making of "zirkite" bricks and cement. In rare cases, used as a cobalt groundcoat constituent. Zirconium silicate is used in formulation of zircon enamels that depend upon crystallization of zircon compounds for opacity development. See also: zircon sand. Enam. Dict. zirconium-vanadium blue A pigment for use in ceramic glazes. The composition is (parts by weight): ArO2 , 60% to 70%; SiO2 , 26% to 36%; V2 O5 , 3% to 5%. Alkali must also be present; e.g., 0.5% to 5% Na2 O. In the absence of alkali, a green color is produced. Syn: vanadium-zirconium turquoise zirconolite A discredited syn. of zirkelite. zircon sand a. A very refractory mineral, composed chiefly of zirconium silicate, having low thermal expansion and high thermal conductivity. ASM, 1 b. A natural zircon-bearing material found in Australia, India, and Florida. See also: zirconium silicate zirkelite a. A monoclinic mineral, (Ca,Th,Ce)Zr(Ti,Nb)2 O7 ; pseudocubic; dimorphous with calciobetafite of the pyrochlore group; radioactive; occurs in pyroxenite and alluvial deposits. b. An obsolete name for altered basaltic glass. 3654

Zirkite A trade name for a mixture of zircon and baddeleyite. USBM, 7 zirklerite A trigonal mineral, (Fe,Mg)9 Al4 Cl18 (OH)12 .14H2 O ; massive fine granular; at Hanover, Germany. zoisite An orthorhombic mineral, CaAl3 (SiO4 )3 (OH)] ; epidote group; dimorphous with clinozoisite; vitreous or pearly; varicolored; a common rock-forming mineral in mediumgrade metamorphic rocks. The rose-red variety has been called thulite. zonal axis See: zone axis zonal structure A term used esp. in miscroscopic work to describe those minerals whose cross sections show their successive concentric layers of growth. Fay zonal theory A theory of hypogene mineral-deposit formation, and the spatial distribution patterns of mineral sequences to be expected from change in a mineral-bearing fluid as it migrates away from a magmatic source. It also deals with thermal-chemical gradients associated with the genesis of ore deposits, whether of direct magmatic origin or not, and with metallogenic zoning on a regional scale. AGI zone a. A belt, band, or strip of earth materials, however disposed; characterized as distinct from surrounding parts by some particular property or content; e.g., zone of saturation, fault zone, or a zone of secondary enrichment. CF: belt b. See: aureole c. A minor interval in any category of stratigraphic classification. There are many kinds of zones, depending on the characteristics under consideration--biozones, lithozones, chronozones, mineralized zones, metamorphic zones, zones of reversed magnetic polarity, etc. The term should always be preceded by a modifier indicating the kind of zone to which reference is made. AGI d. A metal zone is equivalent to a mineral zone, yet the terms mineral and metal are not synonymous. Ricketts e. The ground or mass bounded by horizontal or inclined planes or curved surfaces in which given chemical or physical conditions exist, such as zone of saturation or zone of weathering. Nelson f. A group of 3655

beds characterized by the presence of one or more specific fossils; e.g., zonal fossil or fossils. BS, 11 g. Geologically, a distinctively mineralized area, region, or level. In a specific lode or other deposit, the progressive change from upper to lower horizons. At the top is outcrop or gossan, oxidized or weathered. Next is the leached zone, impoverished by dissolution of its values (or part of them), which may be redeposited below in the zone of secondary enrichment. Below this is the primary, or unaltered zone, which consists of the original sulfide formation. Pryor, 3 h. An area or region more or less clearly set off or characterized as distinct from surrounding or adjoining parts; e.g., the mineral zone in a metalliferous region. Webster 2nd i. A series of faces of a crystal whose intersection lines with each other are all parallel. Webster 3rd j. See: zones zone axis That crystallographic direction through the center of a crystal which is parallel to the intersection edges of the crystal faces defining the "crystal zone." Syn: crystal axis; zonal axis. zone melting Highly localized melting, usually by induction heating, of a small volume of an otherwise solid piece. By moving the induction coil along the rod, the melted zone can be transferred from one end to the other. In a binary mixture where there is a large difference in composition on the liquidus and solidus lines, high purity can be attained by concentrating one of the constituents in the liquid as it moves along a rod. ASM, 1 zone of accumulation See: B-horizon zone of aeration A subsurface zone containing water under pressure less than that of the atmosphere, including water held by capillarity, and containing air or gases generally under atmospheric pressure. This zone is limited above by the land surface and below by the water table. It contains vadose water. CF: zone of capillarity zone of capillarity A subsurface zone that overlies the zone of saturation in which capillary voids hold water above the zone of saturation by molecular attraction acting against gravity. CF: zone of aeration zone of cementation

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The layer of the Earth's crust below the zone of weathering in which percolating waters cement unconsolidated deposits by the deposition of dissolved minerals from above. AGI zone of discharge A term suggested for that part of the zone of saturation having a means of horizontal escape. AGI zone of enrichment See: zone of secondary enrichment zone of faces All faces, belonging to one or more forms, the normals to which lie in one plane (the zone plane) and whose edges of intersection are parallel to the zone axis. See also: zone axis zone of flow See: zone of plastic flow zone of fracture a. The outer, rigid part of a glacier, in which the ice is much fractured. AGI b. The upper, brittle part of the Earth's crust in which deformation is by fracture rather than by plastic flow; that region of the crust in which fissures can exist. CF: zone of plastic flow. Syn: zone of rock fracture zone of illuviation See: B-horizon zone of influence The zone of rock surrounding an excavation, in which the additional stresses caused by the excavation are above a certain arbitrary value, is termed the zone of influence. Spalding zone of mobility See: asthenosphere zone of oxidation 3657

See: oxidized zone zone of plastic flow That part of the Earth's crust that is under sufficient pressure to prevent fracturing, i.e., is ductile, so that deformation is by flow. CF: zone of fracture. AGI zone of rock flowage See: zone of plastic flow zone of rock fracture The upper part of the lithosphere in which rocks are under stresses less than the stresses required to close their interstices by deformation of the walls of the interstices. AGI zone of saturation A subsurface zone in which all the interstices are filled with water under pressure greater than that of the atmosphere. This zone is separated from the zone of aeration (above) by the water table. Syn: saturated zone; phreatic zone. AGI zone of secondary enrichment The zone in which supergene enrichment has taken place. zone of substantial deformation See: destressed area zone of weathering The superficial layer of the Earth's crust above the water table that is subjected to the destructive agents of the atmosphere and in which soils develop. CF: zone of cementation zone refining A purification technique in which a molten or high-temperature zone is moved along a length of material to be purified to bring about impurity segregation; the impurities become concentrated in the slowly moving hot zone, leaving behind the cooler solidified material that has a higher purity than the original material. The technique depends on differences in composition of liquids and solids in equilibrium and may be repeated to attain high degrees of purity. It usually is applied to crystalline materials, such as germanium or silicon. 3658

zones In a shaft furnace, the different portions (horizontal sections) are called zones, and are characterized according to the reactions that take place in them, as the zone of fusion or smelting zone, the reduction zone, etc. Fay zones of lode A lode may be divided into three main zones: (1) unaltered ore at depth; (2) gossan or altered surface portion of the lode, which contain native metals, oxides, and oxysalts that result from weathering of the ore; and (3) secondary enrichment which lies between the first two zones, where interaction between waters from the gossan and the unaltered ore have produced new materials, often of considerable economic value. Nelson zone time Standard time applied at sea in which the surface of the globe is divided into 24 zones of 15 degrees , or of 1 h, each. The "0 zone" extends 7.5 degrees east and west of the meridian of Greenwich (England), (the Prime Meridian); the zones are designated by the number of hours that must be applied to the local time to obtain Greenwich time. Abbrev., ZT. Webster 3rd zoning a. In ore deposits, the spatial distribution patterns of elements, minerals, or mineral assemblages. AGI b. A variation in the composition of a crystal from core to margin, due to a separation of the crystal phases during its growth, by loss of equilibrium in a continuous reaction series. The higher-temperature phases of the isomorphic series form the core, with the lower-temperature phases toward the margin. Syn: zonal structure c. Concentric layering parallel to the periphery of a crystal, shown by color banding, such as in tourmaline, and by differences in optical reactions to polarized light, such as in plagioclase feldspar. CF: undulatory extinction d. In a mineral deposit, the occurrence of successive minerals or elements outward from a common center. e. The development of areas of metamorphosed rocks that may exhibit zones in which a particular mineral or suite of minerals is predominant or characteristic, reflecting the original rock composition, the pressure and temperature of formation, the duration of metamorphism, and whether or not material was added or removed. zoning of ore deposits Spatial distribution patterns of elements, minerals, or mineral assembalages; paragenetic sequences, either syngenetic or epigenetic. Zoning is esp. well developed in the mineralization-alteration assemblages about subvolcanic occurrences such as porphyry base-metal deposits. See also: zonal theory 3659

zonite A name that has been used in Arizona for locally occurring jasper or chert of various colors. zonochlorite A light and dark green variety of pumpellyite in green pebbles of banded structure; occurs in the Lake Superior region, MI. Zonolite A trade name for a light, flaky material obtained by roasting vermiculite, which swells to 15 times its original volume, forming golden yellow scales; from Libby, MT. A titaniumbearing jefferisite from Westcliffe, CO., is similar. English zooplankton The animal forms of plankton, e.g., jellyfish. They consume phytoplankton. AGI zorgite A brass-yellow metallic mineral with dark yellow streak; possibly clausthalite with umangite. Z reagent Any of the Dow series of xanthate flotation reagents. Pryor, 3 zunyite An isometric mineral, Al13 Si5 O20 (OH,F)18 Cl; occurs in transparent tetrahedral crystals, also minute cubes; at the Zuni Mine, Silverton, CO. Also spelled zungite. zurron A rawhide sack that holds about 150 lb (68.1 kg); used by miners for carrying ore. Nelson zwieselite A monoclinic mineral, (Fe,Mn)2 (PO4 )F; forms a series with triplite; clove-brown.

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Dictionary of Medical Terms

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Dictionary of Medical Terms

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