Appendix:Dictionary of Mining, Mineral, and Related Terms/G/3

goaf
 * a. That part of a mine from which the coal has been worked away and the space more or less filled up with caved rock. See also: cundy.

b. The refuse or waste left in the mine.

goaves
 * Old workings.

gob
 * a. A common term for goaf.

b. To leave coal and other minerals that are not marketable in the mine. c. To stow or pack any useless underground roadway with rubbish. d. To store underground, as along one side of a working place, the rock and refuse encountered in mining. e. The space left by the extraction of a coal seam into which waste is packed or the immediate roof caves. f. A pile of loose waste in a mine, or backfill waste packed in stopes to support the roof. g. Coal refuse left on the mine floor. h. The material so packed or stored underground. i. To fill with goaf, or gob; to choke; as a furnace is gobbed, or gobs up. See also: gobbing.

gobber
 * a. Any device used for gobbing waste material.

b. A person employed to pack rubbish or waste into the gob.

Gobber
 * Trade name for a cutting machine provided with a conveyor for gobbing the unusable cuttings formed during the cutting operation.

gobbing
 * The act of stowing waste in a mine. Also called gobbing-up. See also: gob.

gobbing slate
 * A thick layer of slate between two seams of coal. The lower seam is mined and the upper seam and the slate are shot down; the coal is loaded out and then the slate is gobbed.

gobbing the bone
 * Cleaning up slate.

gob dump
 * See: gob pile.

gob entry
 * A wide entry with a heap of refuse or gob along one side.

gob fire
 * a. Fire originating spontaneously from the heat of decomposing gob. Also called breeding fire.

b. A fire occurring in a worked-out area, due to ignition of timber or broken coal left in the gob. c. Fire caused by spontaneous heating of the coal itself, and which may be wholly or partly concealed. See also: oxidation of coal; spontaneous combustion.

gob heading
 * a. A roadway driven through the gob after the filling has settled.

b. Gob road.

gob pile
 * An accumulation of waste material such as rock or bone, either on the surface or underground. Syn: gob dump.

gob-pile orator
 * A more or less unflattering term applied to a talkative miner, used much in the same sense as "soapbox orator."

gob road
 * Eng. A gallery or road extended through goaf or gob.

gob-road system
 * Eng. A form of the longwall system of working coal, in which all the main and branch roadways are made and maintained in the goaves.

gob room
 * Space left for stowing gob.

gob wall
 * A rough wall of flat stones built to prevent the piles of gob from obstructing the passage of air.

go-devil
 * a. A device used to scrape and descale pipes carrying solids, pulps, sludges, slurries, and other deposit-forming liquors.

b. A rude sledge upon which one end of a log is borne, the other end trailing on the ground; tieboy; also, a rough, strong wagon used in the woods and about quarries. c. An iron rod dropped down a well to explode a charge of nitroglycerin. d. See: bullet.

go-devil plane
 * In the United States, a term for gravity haulage.

Godfrey furnace
 * A furnace with an annular hearth for roasting sulfide ores; used in Wales.

goethite
 * An orthorhombic mineral, alpha-Fe (super 3+) O(OH) ; polymorphous with akaganeite, feroxyhyte, and lepidocrocite; dull to adamantine, varicolored with yellow ocher streak; a common weathering product of iron-bearing minerals; precipitates in bogs and springs; a major constituent of limonite and gossans, and a source of iron and a yellow ochre pigment. A hydrous oxide mineral of iron. Also spelled goethite, gothite. Formerly called allcharite; xanthosiderite. CF: bog iron. Syn: yellow ocher.

goffan
 * a. Corn. A surface working in which the material is thrown from one platform to another.

b. Corn. A long narrow surface working. See also: coffin.

Gohi iron
 * Copper-bearing iron, very low in impurities and in carbon (0.02% maximum), containing about 0.25% copper.

going
 * Scot. Working, for example, a going place. A room in the course of being worked.

going bord
 * a. A roadway to the coal face in bord and pillar working.

b. Eng. The bord or headway used as a main road for conveying the tubs to and from the face to a flat. See also: flat. Also called going headway. c. N. of Eng. A bord (room) down which coal is trammed, or one along which the coal from several working places is conveyed into the main haulage.

going headway
 * A headway or bord laid with rails, and used for conveying the coal cars to and from the face.

going in
 * The act or process of lowering the drill string, a string of pipe, or casing into a borehole.

going off
 * A borehole, the course of which is deviating from that intended. Also called drifting; walking; wandering.

going road
 * A working place in a coal mine which is being pushed forward, as distinct from an old or disused place.

Golconda
 * An ancient and famous group of diamond mines on the Kistna River, India, where the Koh-i-noor and other world-famous diamonds were found.

gold
 * a. An isometric mineral, native 4[Au] ; commonly alloyed with silver or copper, possibly with bismuth, mercury, or the platinum-group metals; metallic yellow; soft and malleable; sp gr, 19.3 if pure; occurs in hydrothermal veins with quartz and various sulfides; disseminated in submarine massive effusives and in placers or nuggets, fines, and dust.

b. Found in nature as the free metal and in tellurides; very widely distributed. Symbol: Au. Occurs in veins and alluvial deposits; often separated from rocks and other minerals by sluicing and panning operations. Good conductor of heat and electricity. Used in coinage, jewelry, decoration, dental work, plating, and for coating certain space satellites. It is a standard for monetary systems in many countries. Syn: palladium gold.

goldamalgam
 * A variety of native gold containing mercury and silver, with gold averaging approx. 40%, commonly associated with platinum in yellowish-white grains that crumble easily. CF: amalgam.

gold amalgam
 * Former spelling of goldamalgam. See also: amalgam.

gold argentide
 * See: electrum.

goldbeaters' skin
 * The prepared outside membrane of the large intestine of cattle used for separating the leaves of metal in goldbeating and sometimes as the moisture-sensitive element in hygrometers.

gold cupride
 * See: cuproauride; auricupride.

gold dust
 * Fine particles, flakes, or pellets of gold, e.g., as obtained in placer mining.

golden beryl
 * A clear, golden-yellow or yellowish-green gem variety of beryl. CF: heliodor.

golden ocher
 * a. A native ocher.

b. A mixture of light yellow ocher, chrome yellow, and whiting.

golden stone
 * Greenish-yellow peridot (olivine). Not to be confused with "goldstone."

gold fever
 * A mania for seeking gold; applied specif. to the excitement caused by the discovery of gold in California in 1848-49.

goldfieldite
 * An isometric mineral, Cu (sub 12) (Te,Sb,As) (sub 4) S (sub 13) ; tetrahedrite group; metallic; at the Mohawk Mine, Goldfield, NV.

goldfoil
 * Gold beaten or rolled out very thin; gold in sheets thicker than goldleaf.

gold glass
 * A term sometimes applied to goldstone. Also spelled gold fluss.

goldichite
 * A monoclinic mineral, KFe(SO (sub 4) ) (sub 2) .4H (sub 2) O ; in soft, pale-green radiating clusters of prismatic laths and fine-grained crystalline crusts from decomposition of pyrite; associated with coquimbite, halotrichite, and roemerite on Calf Mesa, San Rafael Swell, UT.

Goldich's stability series
 * Mineral species differ widely in their resistance to weathering processes. This series summarizes the relative resistance to weathering of the common rock-forming silicates, and indicates that the minerals crystallized at the highest temperatures, under the most anhydrous conditions, are more readily weathered than those that crystallized last from the lower temperature, more aqueous magmas.

goldleaf
 * Extremely fine layers of gold formed by beating or rolling between layers of goldbeaters' skin; used for gilding works of art, fabrics, and books.

goldmanite
 * An isometric mineral, Ca (sub 3) (V,Al,Fe) (sub 2) (SiO (sub 4) ) (sub 3); garnet group; forms dark-green dodecahedra and minute grains embedded in vanadium-rich clay; at Laguna uranium mining district, NM.

gold matrix
 * Gold in a matrix of milky quartz. Syn: gold quartz.

gold milling
 * A general term applied to the treating of ore to recover gold and silver therefrom.

gold mine
 * A mine containing or yielding gold. It may be either in solid rock (quartz mine) or in alluvial deposits (placer mine).

gold opal
 * A fire opal that exhibits only an overall color of golden yellow.

gold pan
 * See: pan.

gold poachers
 * Roving and enterprising freelance miners and prospectors.

gold quartz
 * Milky quartz containing small inclusions of gold; may be cut and polished for jewelry. Syn: gold matrix.

gold-quartz ores
 * Gold-bearing ore from which the sulfides have been removed by the leaching of ground waters so that the ore consists almost entirely of quartz gangue, some iron oxides, and free gold.

gold sapphire
 * A misnomer for lapis lazuli containing flecks of pyrite. Not to be confused with golden sapphire.

goldschmidtine
 * See: stephanite.

goldschmidtite
 * See: sylvanite.

Goldschmidt's phase rule
 * See: mineralogical phase rule.

Goldschmidt's process
 * a. The thermite process of welding.

b. The removal of tin from scrap tinplate by dry chlorine.

goldstone
 * a. Aventurine spangled close and fine with particles of gold-colored material. CF: aventurine.

b. A translucent reddish-brown glass containing a multitude of tiny tetrahedra or thin hexagonal platelets of metallic copper that exhibit bright reflections, producing a popular but poor imitation of aventurine. Syn: aventurine glass; fire agate. CF: sunstone.

gold telluride
 * a. Minerals containing tellurium forming tellurides of gold and silver; e.g., sylvanite, calaverite, and petzite.

b. One of several natural tellurides of gold and silver, e.g., sylvanite, (Au,Ag) (sub 2) Te (sub 4) ; calaverite, AuTe (sub 2) ; and petzite, Ag (sub 3) AuTe (sub 2).

gold topaz
 * a. A misnomer for heat-treated citrine.

b. A misnomer for naturally colored citrine. Syn: false topaz; topaz-quartz.

goliath crane
 * A portal type of crane having a lifting capacity of 50 st (45 t) or more, with the crab traveling along the horizontal beam. See also: portal crane.

Gommesson method
 * A specialized method of surveying a borehole, utilized when a magnetic compass cannot be used because of local magnetism. The instrument used is essentially a rigid tube, up to 30 ft (9.2 m) long, which is lowered into a borehole. The tube fits the borehole closely and contains a fine wire under tension. The difference between the arc of the tube, when bent at a crook in the borehole, and the chord of the wire is indicated by a stylus marking, which can be measured. The dip is read by etch tubes, and a directional orientation taken at the surface is carried down the hole by precise alignment of the tube and rods as they are lowered into the borehole.

gondola
 * A railroad car with no top, flat bottom, fixed sides, and sometimes demountable ends that is used chiefly for hauling heavy bulk materials. CF: high side.

gondola car
 * Type of open freight truck used in the United States for mineral transport.

gone off
 * A borehole that has deviated from the intended course.

goniometer
 * a. In crystallography, an instrument for measuring angles between crystal faces. Types are contact, two-circle, and reflection. See also: contact goniometer.

b. The part of an X-ray diffractometer that rotates the sample and detector through the Bragg angles of diffraction. c. A specimen holder with three rotation axes for orientation of single crystals relative to the X-ray beam in Laue and Wiessberg photography. Syn: three-circle goniometer. CF: two-circle goniometer; spindle stage; universal stage.

gonnardite
 * An orthorhombic mineral, Na (sub 2) CaAl (sub 4) Si (sub 6) O (sub 20) .7H (sub 2) O ; zeolite group; forms white, finely fibrous, radiating spherules in cavities in basalt, and as an alteration of nepheline.

gonyerite
 * A possibly orthorhombic mineral, (Mn,Mg) (sub 5) Fe(Si (sub 3) Fe)O (sub 10) (OH) (sub 8) ; chlorite group; pseudohexagonal with basal cleavage; soft; with barite, berzeliite, and garnet in small hydrothermal veinlets cutting skarn at Laangban, Sweden.

good delivery
 * Under Metal Exchange rulings, description of metal delivered at an agreed purity or of a defined quality.

goodletite
 * The green-amphibole or green-pyroxene matrix rock in which rubies are embedded; Australia and New Zealand.

Goodman duckbill loader
 * The duckbill assembly consists of five major units: (1) a shovel trough to which is attached the shovel head fitting inside the feeder trough, (2) an operating carrier that controls the connection or coupling between the feeder and shovel troughs, (3) a sliding shoe that moves to and fro on the floor of the seam, (4) a swivel trough, and (5) a pendulum jack. The function of the duckbill is to gather the coal and load it into the shaker conveyor pan column. The shovel is forced into the prepared coal by the forward motion of the pan column. As the shovel is propelled forward, the coal is conveyed back along the shovel trough and then to the pan column.

Goodman miner
 * A continuous miner designed for driving coal headings in medium to thick seams. The machine is crawler-mounted and equipped with two triple-arm rotating cutting units and a chain conveyor. The cut coal is discharged on to the chain conveyor which delivers into shuttle or mine cars. Also called Goodman-type 500 miner. See also: continuous miner.

goods
 * A trade term for a lot, parcel, or shipment of diamonds without regard to quality, composition, or quantity.

good-shooting coal
 * Arkansas. Coal that can be shot "off the solid" with a large proportion of lump coal and little slack.

gooseberry stone
 * A yellowish-green variety of grossular.

goose dung ore
 * An inferior grade of iron sinter containing silver. Also called goose silver ore.

gooseneck
 * a. In drilling, the bent-tube part of a water swivel to which the water hose is connected.

b. A T-shaped connection for supplying water to the top end of wash rods in penetrating overburden. It is fitted with pipe handles by means of which the wash rods may be turned.

goosing
 * In hydraulic mining, driving the gravel forward with the stream from the giant. Opposite of drawing.

gopher
 * An irregular prospecting drift following or seeking the ore without regard to maintenance of a regular grade or section. Also called gopher drift.

gopher hole
 * Horizontal opening in wall of quarry, perhaps chambered or tee-headed in preparation for blasting. Also, an irregular pitting hole made when prospecting. Gophering is random prospecting by such pits or by gopher drift. Also called coyote hole.

gopher hole blasting
 * Terms applied to the method of blasting in which large charges are fired in small adits driven into the face of the quarry at the level of the floor. See also: tunnel blasting.

gophering
 * a. A method of breaking up a sandy, medium-hard overburden where blastholes tend to cave in. A series of shallow holes are made by a bar, and an explosive charge is fired in each. The debris is removed, and the holes are deepened and further charges fired until the holes are deep enough to take sufficient explosives to break the entire deposit.

b. The haphazard working of the easiest and richest portions of an ore deposit by miners with little or no capital.

gopherman
 * In metal mining, one who extracts ore located in pockets or other parts not accessible for machine drilling in an open pit mine.

gor
 * York. Sticky, dirty clay. Also spelled gore.

gorceixite
 * A monoclinic mineral, BaAl (sub 3) (PO (sub 4) )(PO (sub 3) OH)(OH) (sub 6) ; crandallite group; pseudotrigonal; forms spheroids in fractured novaculite, Garland County, AR; and as rolled pebbles (favas) in the diamantiferous sands of Brazil and Guyana.

gordonite
 * A triclinic mineral, MgAl (sub 2) (PO (sub 4) ) (sub 2) (OH) (sub 2) .8H (sub 2) O ; paravauxite group; in glassy lath-shaped crystals in crusts with variscite; near Fairfield, UT.

Gordon's rule
 * A rule by which the capacity of hydraulic elevators is computed. It is as follows: M = H x N/C, where M = cubic yards of material lifted per hour, H = available head of water in feet, N = water flow in cubic feet per second, C = the efficient working height of the elevator, taken as head H in hundreds of feet multiplied by 15.

goergeyite
 * A monoclinic mineral, K (sub 2) Ca (sub 5) (SO (sub 4) ) (sub 6) .H (sub 2) O ; forms small, tabular crystals with glauberite and minor halite in salt deposits at Ischl, Austria. Syn: mikheevite.

gorgulho
 * A diamond-bearing quartz and clay gravel of Brazil.

gorse
 * A barrel or tub for carrying water underground.

goshenite
 * A colorless, white, or bluish beryl from Goshen, MA.

goslarite
 * An orthorhombic mineral, ZnSO (sub 4) .7H (sub 2) O ; in acicular or hairlike crystals, or massive; a decomposition product of sphalerite on recent mine workings at Butte, MT, and Bingham Canyon, UT. Syn: copperas; white copperas; zinc vitriol.

gossan
 * An iron-bearing weathered product overlying a sulfide deposit. It is formed by the oxidation of sulfides and the leaching-out of the sulfur and most metals, leaving hydrated iron oxides and rarely sulfates. Syn: capping; iron hat; chapeau de fer. Also spelled gozzan. CF: oxidized zone; false gossan.

goth
 * Staff. Sudden bursting of coal from the face, owing to tension caused by unequal pressure. The term "airblast" is sometimes used in metal mines, esp. in South Africa.

got-on-knobs
 * S. Staff. A system of working thick coal, being a kind of bord-and-pillar plan, the main roadways being first driven to the boundary.

gotten
 * a. An abandoned or exhausted mine.

b. Coal ready to be filled underground into tubs or trains.

gouge
 * a. A layer of soft, earthy or clayey, fault-comminuted rock material along the wall of a vein, so named because a miner can "gouge" it out to facilitate the mining of the vein itself. Syn: selvage; pug. See also: gouge clay; hulk.

b. The clay or clayey material along a fault or shear zone. Also called clay gouge. See: fault gouge. c. To work a mine without plan or system.

gouge angle
 * The angle at which the surface of a cutting edge in a drill bit is inclined in relation to the surface of the material being cut. See also: negative rake; positive rake.

gouge clay
 * Clay infillings in a mineral vein. CF: gouge.

gouge rake
 * See: positive rake.

gouging
 * a. In placer mining, an operation similar to ground sluicing. Also called booming.

b. The formation of "crescentic gouges." c. The local basining of a bedrock surface by the action of glacier ice. d. The working of a mine without plan or system, by which only the high-grade ore is mined. Syn: high-grading.

gouging shot
 * A gripping shot or opening shot used to make the first opening in a straight-room face, or to start a breakthrough. See also: shot.

goutwater
 * Forest of Dean. Mine water containing hydrogen sulfide, H (sub 2) S.

Gouy layer
 * Modification of the Helmholtz concept of the electrical double layer which surrounds a particle immersed in an electrolyte. In Gouy's view there is only one diffuse layer. The ionic atmosphere near the surface of the particle is highly charged, but this ionization diminishes gradually outward into the ambient liquid.

gow caisson
 * A device for sinking shafts of small diameter through silt or clay without excessive loss of ground.

gozzan
 * See: gossan.

GPS
 * See: Global Positioning System.

grab
 * An instrument for extricating broken boring tools from a borehole.

grabbing crane
 * An excavator consisting of a crane carrying a large grab or bucket in the form of a pair of half-scoops, so hinged as to scoop or dig into the earth as they are lifted.

grab bucket
 * An underwater digging device which, in closing, bites into the sediment and contains it inside the closed shell. The bucket and load are then hoisted to the surface where the shell is opened to dump the load. Includes clamshells, orangepeels, and other variations.

grab-camera
 * An ocean floor sampling system incorporating a large sediment grab with a deep-sea camera.

grab dredger
 * A dredging appliance consisting of a grab or grab bucket suspended from the jib head of a crane, which does the necessary raising and lowering. Also called a grapple dredger. See also: dredger.

graben
 * An elongate, relatively depressed crustal unit or block that is bounded by faults on its long sides. It is a structural form that may or may not be geomorphologically expressed as a rift valley. Etymol: Ger., ditch. CF: horst. Syn: trough; rift structure.

grab equipment
 * A clamshell bucket fitted with teeth to assist digging.

grabhooks
 * Hooks used in lifting blocks of stone. They are used in pairs connected with a chain, and are so constructed that the tension of the chain causes them to adhere firmly to the rock.

grab iron
 * A short railing or handle on heavy equipment used to assist operators and other personnel in climbing up or down.

grab sampler
 * An ocean-bottom sampler that commonly operates by enclosing material from the seafloor between two jaws upon contact with the bottom. See also: Petersen grab. CF: dredge. Syn: snapper.

grab sampling
 * Collection of specimens of ore more or less at random from a heap, scatter pile, or passing load. Used in connection with examination of the characteristic minerals in the deposit rather than for valuation.

gradall
 * Essentially a hydraulic backhoe equipped with an extensible boom that performs the three separate functions of excavation, backfill, and grading.

gradation
 * a. The leveling of the land, or the bringing of a land surface or area to a uniform or nearly uniform grade or slope through erosion, transportation, and deposition; specif. the bringing of a streambed to a slope at which the water is just able to transport the material delivered to it. See also: degradation; aggradation.

b. The proportion of material of each particle size, or the frequency distribution of various sizes, constituting a particulate material such as a soil, sediment, or sedimentary rock. The limits of each size are chosen arbitrarily.

grade
 * a. A coal classification based on degree of purity, i.e., quantity of inorganic material or ash left after burning. CF: type; rank.

b. The relative quantity or the percentage of ore-mineral or metal content in an orebody. Syn: tenor. c. A degree of inclination, or a rate of ascent or descent, with respect to the horizontal, of a road, railroad, embankment, conduit, or other engineering structure; it is expressed as a ratio (vertical to horizontal), a fraction (such as m/km or ft/mi), or a percentage (of horizontal distance). CF: gradient. d. Height above sea level; actual elevation. Also, the elevation of the finished surface of an engineering project (such as of a canal bed, embankment top, or excavation bottom). e. A particular size (diameter), size range, or size class of particles of a soil, sediment, or rock; a unit of a grade scale, such as clay grade, silt grade, sand grade, or pebble grade. f. See: metamorphic grade. g. The classification of an ore according to the desired or worthless material in it or according to value. h. The degree of strength of a high explosive. Those above 40% nitroglycerin are arbitrarily designated as high-grade dynamites, and those below 40% nitroglycerin as low-grade dynamites. i. In assaying, the percentage of the sought value or of each valuable species in the ore. j. A term used to designate the extent to which metamorphism has advanced. Found in such combinations as high- or low-grade metamorphism. CF: rank. k. A particular occupational classification of employee in a mine. l. To sort and classify diamonds, such as drill diamonds, into quality groupings, each group containing diamonds having somewhat similar characteristics deemed to affect their fitness for use in a specific manner; the least fit are considered as constituting the lowest quality of grade. m. See: rank.

graded
 * a. Said of a surface or feature when neither degradation nor aggradation is occurring, or when both erosion and deposition are so well balanced that the general slope of equilibrium is maintained. Syn: at grade.

b. A geologic term pertaining to an unconsolidated sediment or to a cemented detrital rock consisting of particles of essentially uniform size or of particles lying within the limits of a single grade. Syn: sorted. c. An engineering term pertaining to a soil or an unconsolidated sediment consisting of particles of several or many sizes or having a uniform or equable distribution of particles from coarse to fine; e.g., a graded sand containing coarse, medium, and fine particle sizes. The term is rarely used in geology to refer to the sorting of the sediment, although this is common among engineers. Ant: nongraded.

graded bedding
 * A type of bedding in which each layer displays a gradual and progressive change in particle size, usually from coarse at the base of the bed to fine at the top. It may form under conditions in which the velocity of the prevailing current declined in a gradual manner, as by deposition from a single short-lived turbidity current. CF: grading.

graded coal
 * One of the three main size groups by which coal is sold by the National Coal Board in Great Britain. It consists of coal screened between two screens--with an upper and lower limit ranging from a top size of 1-1/2 to 2 in (38 to 51 mm) to a bottom size of 1/8 to 3/4 in (3.2 to 19 mm). See also: large coal; smalls.

graded sand
 * A sand containing some coarse, fine, and medium particle sizes. It is not a uniform sand.

graded stream
 * A stream in equilibrium, showing a balance between its transporting capacity and the amount of material supplied to it, and thus between degradation and aggradation in the stream channel.

graded unconformity
 * See: blended unconformity.

gradeline
 * a. The baseline from which elevations are measured.

b. A line defining the intended grade of a roadway that is being driven. Such a line is used to control the gradient of a roadway.

grader
 * a. A self-propelled or towed machine provided with a row of removing or digging teeth and (behind) a blade to spread and level the material. Syn: towed grader.

b. A trommel-type airswept circular screen used in asbestos milling where the fine rock and fiber dust are eliminated through medium-size perforated plates. c. A machine with a centrally located blade that can be angled to cast to either side, with independent hoist control on each side.

grade resistance
 * The force, due to gravity, that resists the movement of a vehicle up a slope.

grade scale
 * A systematic, arbitrary division of an essentially continuous range of particle sizes (of a soil, sediment, or rock) into a series of classes or scale units (or grades) for the purposes of standardization of terms and of statistical analysis; it is usually logarithmic. Examples include Udden scale and Tyler Standard scale. See also: Udden grade scale; Wentworth scale.

grade stake
 * A stake indicating the amount of cut or fill required to bring the ground to a specified level.

gradient
 * The inclination of profile gradeline from the horizontal, expressed as a percentage. Syn: rate of grade.

gradienter
 * An attachment to a surveyor's transit with which an angle of inclination is measured in terms of the tangent of the angle instead of in degrees and minutes. It may be used as a telemeter in observing horizontal distances.

gradient of equal traction
 * The gradient at which the tractive force required to pull an empty tram inby (slightly uphill) is equal to that required to pull a loaded tram outby. This was formerly termed horse haulage gradient. In general, haulage roads are graded about 0.5% in favor of the loaded trams.

grading
 * a. The relative proportions of the variously sized particles in a batch, or the process of screening and mixing to produce a batch with particle sizes correctly proportioned.

b. The commercial operation of sorting coke between two screens such that the ratio of the larger to the smaller screen aperture does not exceed 2.5 to 1; the coke which has been so sorted. c. The gradual reduction, upward in a sedimentary bed, of the upper particle-size limit. It implies pulsatory turbulent-fluid deposition. CF: graded bedding.

grading test
 * See: screen analysis.

Graf sea gravimeter
 * A balance-type gravity meter that is heavily damped in order to attenuate shipboard vertical accelerations. It consists of a mass at the end of a horizontal arm, supported by a torsion-spring rotational axis. The mass rises and falls with gravity variation, but is restored to near its null position by a horizontal reading spring, tensioned with a micrometer screw. The difference between actual beam position and null position gives indication of gravity value after the micrometer screw position has been taken into account. See also: gravimeter.

Graham pressure surveying apparatus
 * the aneroid barometer. The apparatus records the change in pressure of a constant volume of air maintained at a constant temperature.

Graham ratio
 * The ratio of the amount of carbon monoxide produced over the oxygen absorbed varies with the temperature of oxidation of coal and also with the time of coal exposure to oxidation, thereby allowing this ratio to be used as an index of the rate of oxidation in a mine.

grail
 * Gravel or sand; anything in fine particles.

grain
 * a. A mineral or rock particle having a diameter of less than a few millimeters and generally lacking well-developed crystal faces; e.g., a sand grain. Also, a general term for sedimentary particles of all sizes (from clay to boulders), as used in the expressions grain size, fine-grained, and coarse-grained.

b. A quarrymen's term for a plane of parting in slate that is perpendicular to the flow cleavage; or for a direction of parting in massive rock, e.g., granite, that is less pronounced than the rift and usually at right angles to it. CF: rift. c. The second direction of easy splitting of a rock, less pronounced than the rift, but more so than the hardway. d. A unit of hardness of water, expressed in terms of equivalent CaCO (sub 3). A hardness of 1 grain per U.S. gal (17.1 mg/L) equals 17.1 ppm by weight as CaCO (sub 3). See also: anthracite fines.

grain boundary
 * An interface between two crystals putting all adjacent ions in an irregular crystalline environment. CF: lineage.

grainer medium salt
 * Grainer salt screened to give a mixture of coarse- and medium-size flakes, excluding very coarse and very fine flakes.

grainers
 * Diamonds which in weight will correspond to fourths of a carat; a diamond weighing one-half carat is a two-grainer; one weighing three quarters is a three-grainer; a diamond of one carat in weight is a four-grainer.

grainer salt
 * Salt produced by the grainer process of surface evaporation from brine. Product has a characteristic flaky shape consisting of hoppers and hopper fragments.

grain gliding
 * Movement between individual mineral grains.

grain gold
 * Gold that has become granular in the process of heating.

grain growth
 * The growth of a crystal, as from solution on the walls of a geode, in open pore space, or in a magma chamber; crystal growth.

grain size
 * a. A term relating to the size of mineral particles that make up a rock or sediment. See also: particle size.

b. For metals, a measure of the size of grains in a polycrystalline material, usually expressed as an average when the individual sizes are fairly uniform. Grain sizes are reported in terms of number of grains per unit area or volume, as average diameter, or as a grain-size number derived from area measurements. c. The size or size distribution of refractory particles, which is usually determined by sieve analysis.

grain-size classification
 * A scheme of rock classification based upon the average size of certain chosen components; thus, each clan comprises coarse-, medium-, and fine-grained members.

grain tin
 * a. The granular or nodular form of cassiterite, tin oxide, SnO (sub 2) ; also known as stream tin.

b. Metallic tin of high grade obtained by charcoal reduction.

graith
 * A set of tools, picks, shovels, wedges, hammers, etc., used for work underground.

gram-atom
 * The atomic weight of an element expressed in grams.

gram-centimeter
 * A unit of work; the work done in raising the weight of 1 g vertically 1 cm; 981 ergs.

gram-molecule
 * Molecular weight of a compound in grams, derived from that of hydrogen which, though 2.016, is expressed as the whole number 2. The gram-molecule, e.g., of H (sub 2) SO (sub 4) is 2 + 32 + (4 x 16) = 98. Also called mole.

grampus
 * The tongs with which bloomery loups and billets are handled.

gram weight
 * Pull of gravitation on a mass of 1 g. This varies slightly with the acceleration (g) due to gravity differences in various localities, but is approx. 981 dyn.

granat
 * See: garnet.

Granby car
 * A type of automatically dumped car for hand- or power-shovel loading. In this type of car, a wheel attached to the side of the car body engages an inclined track at the dumping point. As the side wheel rides up and over the inclined track, the car body is automatically raised and lowered, activating a side door operating mechanism which raises the door, permitting the car to shed its load. See also: mine car.

grandite
 * The grossular-andradite series of the garnet group.

granite
 * a. A plutonic rock in which quartz constitutes 10% to 50% of the felsic components and in which the alkali feldspar/total feldspar ratio is generally restricted to the range of 65% to 90%. Rocks in this range of composition are scarce, and sentiment has been growing to expand the definition to include rocks designated as adamellite or quartz monzonite, which are abundant in the United States.

b. Broadly applied, any holocrystalline, quartz-bearing plutonic rock. Syn: granitic rock. Etymol: Latin granum, grain. c. Commercial granite.

granite gneiss
 * a. A gneiss derived from a sedimentary or igneous rock and having the mineral composition of a granite.

b. A metamorphosed granite.

granite porphyry
 * A hypabyssal rock differing from a quartz porphyry by the presence of sparse phenocrysts of mica, amphibole, or pyroxene in a medium- to fine-grained groundmass.

granite tectonics
 * The study of the structural features, such as foliation, lineation, and faults, in plutonic rock masses, and the reconstruction of the movements that created them.

granite wash
 * A driller's term for material eroded from outcrops of granitic rocks and redeposited to form a rock having approx. the same major mineral constituents as the original rock; e.g., an arkose consisting of granitic detritus.

granitic
 * Pertaining to or composed of granite. Syn: granitoid. See also: granular texture.

granitic layer
 * See: sial.

granitic rock
 * A term loosely applied to any light-colored, coarse-grained plutonic rock containing quartz as an essential component, along with feldspar and mafic minerals. Syn: granite.

granitification
 * See: granitization.

granitization
 * An essentially metamorphic process by which a solid rock is converted into a granitic rock by the entry and exit of material, without passing through a magmatic stage. Some authors include in this term all granitic rocks formed from sediments by any process, regardless of the amount of melting or evidence of movement. The precise mechanism, frequency, and magnitude of the processes are still in dispute. Syn: granitification. CF: transfusion.

granitizer
 * See: transformist.

granitoid
 * See: granitic.

granoblastic
 * Pertaining to a homeoblastic type of texture in a nonschistose metamorphic rock upon which recrystallization formed essentially equidimensional crystals with normally well sutured boundaries. Syn: granular. CF: crystalloblastic.

granodiorite
 * A group of coarse-grained plutonic rocks intermediate in composition between quartz diorite and quartz monzonite (U.S. usage), containing quartz, plagioclase (oligoclase or andesine), and potassium feldspar, with biotite, hornblende, or, more rarely, pyroxene, as the mafic components; also, any member of that group; the approximate intrusive equivalent of rhyodacite. The ratio of plagioclase to total feldspar is at least 2:1 but less than 9:10. With less alkali feldspar it grades into quartz diorite, and with more alkali feldspar, into granite or quartz monzonite.

granofels
 * A field name for a medium- to coarse-grained granoblastic metamorphic rock with little or no foliation or lineation.

granolith
 * An artificial stone of crushed granite and cement.

granophyre
 * a. An irregular microscopic intergrowth of quartz and alkali feldspar.

b. A fine-grained granitic rock having a micrographic texture. c. A porphyritic rock of granitic composition characterized by a crystalline-granular groundmass. CF: felsophyre; vitrophyre.

granophyric
 * Of or pertaining to granophyre.

grant
 * Eng. A tract of land leased or ceded for mining purposes.

grantsite
 * A monoclinic mineral, NaCa(V (super 5+) ,V (super 4+) ) (sub 6) O (sub 16) .4H (sub 2) O ; in silky, pearly, or subadamantine fibrous aggregates coating fractures or forming thin seams in sandstone or limestone; near Grants, NM, and in Montrose County, CO.

granular
 * Said of the texture of a rock that consists of mineral grains of approx. equal size. The term may be applied to sedimentary rocks, e.g., sandstones, but is esp. used to describe holocrystalline igneous rocks whose major-phase grain size ranges from 2 to 10 mm. The syn. granoblastic is used for metamorphic rocks.

granular chert
 * A compact, homogeneous, hard-to-soft chert, common in insoluble residues, composed of distinguishable and relatively uniform-sized grains, characterized by an uneven or rough fracture surface and by a dull to glimmering luster; it may appear saccharoidal. See also: granulated chert. CF: chalky chert.

granularity
 * The quality, state, or property of being granular; specif. one of the component factors of the texture of a crystalline rock, including both grain size and grain-size distribution.

granular texture
 * A rock texture resulting from the aggregation of mineral grains of approx. equal size. The term may be applied to a sedimentary or metamorphic rock, but is esp. used to describe an equigranular, holocrystalline igneous rock whose particles range in diameter from 0.05 to 10 mm. See also: granitic.

granular tonstein
 * This type of tonstein consists predominately of kaolinite grains of lighter or darker shades, often surrounded by collinite. These grains show a cryptocrystalline to finely crystalline structure; the cryptocrystalline material is isotropic. Syn: Graupen tonstein.

granulated blast-furnace slag
 * The glassy, granular material formed when molten blast-furnace slag is rapidly chilled, as by immersion in water.

granulated chert
 * A type of granular chert composed of rough, irregular grains or granules tightly or loosely held in small masses or fragments. See also: granular chert.

granulated slag
 * Molten slag broken up into granules and quick quenches. Three general methods of granulation are: (1) running the molten slag into a pit of water; (2) using a jet of high-pressure water to breakup the stream of molten slag as it falls into the pit; and (3) using a mechanical revolving device with relatively small amounts of water. See also: slag.

granulated steel
 * Steel made from pig iron by a process in which the first step is the granulation of the iron.

granulating machine
 * A device for reducing metal or slag in a liquid form to fine grain.

granulation
 * The act or process of being formed into grains, granules, or other small particles; specif. the crushing of a rock under such conditions that no visible openings result. Also, the state or condition of being granulated.

granulator
 * a. A rock breaker which converts large stone into small aggregate.

b. A machine that produces body raw material in the form of grains with a minimum of fines.

granule
 * a. A rock fragment larger than a very coarse sand grain and smaller than a pebble, having a diameter in the range of 2 to 4 mm. The term "very fine pebble" has been used as a syn.

b. A little grain or small particle, such as one of a number of the generally round or oval, nonclastic (precipitated), internally structureless grains of glauconite or other iron silicate in iron formation; a pseudo-oolith.

granule texture
 * A texture of iron formation in which precipitated or nonclastic granules are separated by a fine-grained matrix.

granulite
 * a. A metamorphic rock consisting of even-sized, interlocking mineral grains less than 10% of which have any obvious preferred orientation.

b. A relatively coarse, granular rock formed at high pressures and temperatures, which may exhibit a crude gneissic structure due to the parallelism of flat lenses of quartz and/or feldspar. The texture is typically granuloblastic.

granulitic
 * Of, pertaining to, or composed of granulite.

granulitization
 * In regional metamorphism, reduction of the components of a solid rock such as a gneiss to grains. The extreme result of the process is the development of mylonite.

graphic
 * a. Said of the texture of an igneous rock that results from the regular intergrowth of quartz and feldspar crystals. The quartz commonly occupies triangular areas, producing the effect of cuneiform writing on a background of feldspar. Similiar intergrowths of other minerals, e.g., ilmenite-pyroxene, are less common.

b. A mineral intergrowth, e.g., alkali-feldspar and quartz, with angular planar boundaries resembling cuneiform writing.

graphic gold
 * Crystals of naturally occurring sylvanite ore; a mixed gold-silver telluride, occurring in regularity so as to give the appearance of written symbols. Syn: graphic tellurium.

graphic granite
 * a. An intergrowth of potash feldspar (orthoclase or microcline) and quartz. Syn: corduroy spar.

b. A pegmatite characterized by graphic intergrowths of quartz and alkali feldspar. CF: intergrowth.

graphic intergrowths
 * See: graphic granite.

graphic ore
 * See: sylvanite. Also called graphic tellurium.

graphic section
 * A drawing that shows the sequence of strata.

graphic tellurium
 * See: sylvanite; graphic gold.

graphite
 * A hexagonal and trigonal mineral, native carbon 4[C], polymorphous with chaoite, diamond, and lonsdaleite; scaly, soft, lustrous, metallic; greasy feel; as crystals, flakes, scales, laminae, or grains in veins or bedded masses or disseminations in carbonaceous metamorphic rocks; conducts electricity well, is soft and unctuous; immune to most acids; extremely refractory. Syn: plumbago; black lead.

graphitic carbon
 * The portion of the carbon in iron or steel that is present as graphite; distinguished from combined carbon.

graphitic steel
 * Alloy steel made so that part of the carbon is present as graphite.

graphitite
 * A hard, coallike graphite rock interbedded with Precambrian schists. Syn: graphitoid.

graphitization
 * Formation of graphite in iron or steel. If graphite is formed during solidification, the phenomenon is called primary graphitization; if formed later by heat treatment, it is called secondary graphitization.

graphitoid
 * a. Meteoritic graphite.

b. See: graphitite.

grapple
 * A clamshell-type bucket having three or more jaws.

grapple dredge
 * a. A dredge using an orangepeel bucket and operating on the clamshell principle.

b. See: grab dredger.

grass crop
 * Scot. The outcrop of a vein.

Grassellis
 * High explosive; used in mines.

grasshopper conveyor
 * See: oscillating conveyor.

grass roots
 * A miner's term equivalent to the surface. From grass roots down is from the grass roots to the bedrock.

grass-roots deposit
 * The old fabulous deposit, discovered in surface croppings, easy of exploitation, and capable of financing its own development as it went along.

grass-roots mining
 * Inadequately financed operation, depending on hand-to-mouth existence. Mining from surface down to bedrock. At grass; at surface. Also known as mining on a shoestring.

grate
 * a. A screen or sieve for use with stamp mortars for grading ore.

b. A frame, bed, or a kind of basket of iron bars for holding fuel while burning.

grate bar
 * a. A bar forming part of a fire grate.

b. One of the bars forming a coarse screen or grizzly.

grate coal
 * Formerly, coal passing through bars 3-1/4 to 4-1/4 in (8.3 to 10.8 cm) apart and over 2-1/4 in (6.7 cm) round holes. In Arkansas, the bars are 7 in (17.8 cm) apart and the holes are 3 to 3-1/4 in (7.6 to 8.3 cm) in diameter.

grater
 * A laborer who replaces grates on conveyors after roasted lead ore has been dumped into cars, using hooks. Lead ore is loaded on grates and conveyed through a furnace in which the sulfur is driven off by roasting prior to the ore being melted to separate and recover the lead in another furnace.

graticule
 * a. A network of lines representing geographic parallels and meridians forming a map projection.

b. A template divided into blocks or cells, for graphically integrating a quantity such as gravity. Graticules are used in computing terrain corrections and the gravitational or magnetic attraction of irregular masses. c. An accessory to an optical instrument such as a microscope to aid in measurement of the object under study; it is a thin glass disk bearing a scale which is superimposed upon the object. d. The network of lines representing meridians of longitude and parallels of latitude on a map or chart, upon which the map or chart was drawn. Not to be confused with grid.

grating
 * a. A coarse screen made of parallel or crossed bars to prevent passing of oversized material.

b. A series of parallel and crossed bars used as platform or walkway floors or as coverings for pits and trenches over which traffic can pass; generally removable to permit access to conveying equipment for servicing. c. A series of parallel and/or crossed bar units fastened to or propelled by a conveying medium, used for carrying large lump-size bulk material or objects. They usually permit passage of air for cooling or for heat to maintain temperature. d. The act of sorting ores by means of grates.

Graupen tonstein
 * See: granular tonstein.

gravel
 * a. An unconsolidated, natural accumulation of rounded rock fragments resulting from erosion, consisting predominantly of particles larger than sand (diameter greater than 2 mm or 1/12 in), such as boulders, cobbles, pebbles, granules, or any combination of these. See also: pebble.

b. A popular term for a loose accumulation of rock fragments, such as a detrital sediment associated esp. with streams or beaches, composed predominantly of more or less rounded pebbles and small stones, and mixed with sand that may compose 50% to 70% of the total mass. c. An engineering term for rounded fragments having a diameter in the range of 1.87 in (47.5 mm) (retained on U.S. standard sieve No. 4) to 3 in (76 mm).

gravel bank
 * A natural mound or exposed face of gravel, particularly such a place from which gravel is dug; a gravel pit.

gravel deposit
 * See: alluvium.

gravel mine
 * S. Afr. A mine extracting gold from sand or gravel; also called placer mine. See also: gravel pit.

gravel pit
 * A pit from which gravel is obtained. See also: gravel mine.

gravel plain placer
 * Placers along the coastal plain of the Seward Peninsula, AK.

gravel powder
 * Very coarse gunpowder.

gravel pump
 * A centrifugal pump with renewable impellers and lining, suitable for pumping a mixture of gravel and water. Rubber is sometimes used as lining to the pump and pipes owing to its high resistance to abrasion. See also: sand pump.

gravel pumping
 * A method of alluvial mining that consists of (1) excavating and breaking up the gravel bank by using giants or monitors, (2) washing the disintegrated material into a sump, excavated in the bedrock, (3) elevating the mixture from the sump to an elevated line of sluices by means of a gravel pump, and (4) sluicing the gravel for the recovery of its mineral content.

grave wax
 * A natural paraffin. See also: hatchettite.

gravimeter
 * a. An instrument to measure the value of gravity or for measuring variations in the magnitude of the Earth's gravitational field. Measurements of gravity are accomplished generally by one of three methods: dropped ball, pendulum, or spring gravimeter. The latter type of gravimeter, which is based upon the principle of the weighted spring--where the length or measured variations in the length of the spring are a function of the gravitational field at different locations, is the type widely used today. See also: Graf sea gravimeter; gravitational prospecting.

b. An instrument for determining specific gravities, particularly of liquids. See also: hydrometer. c. An instrument that measures variations in the density of underlying rocks. d. An instrument for measuring variations in the gravitational field, generally by registering differences in the weight of a constant mass as the gravimeter is moved from place to place. Syn: gravity meter. See also: astatic gravimeter.

gravimetric analysis
 * Quantitative chemical analysis in which the different substances of a compound are measured by weight.

gravimetry
 * The measurement of gravity or gravitational acceleration, esp. as used in geophysics and geodesy.

gravitation
 * The mutual attraction between two masses. See also: law of gravitation.

gravitational constant
 * The constant, gamma, in the law of universal gravitation. Its value is 6.672 X 10 (super -11) m (super 3) /kg X s (super 2).

gravitational differentiation
 * See: crystal fractionation.

gravitational method
 * A geophysical prospecting method that measures irregularities or anomalies in gravity attraction produced by differences in the densities of rock formations, and interprets the results in terms of lithology and structure.

gravitational prospecting
 * A method of geophysical prospecting, that embraces the mapping of variations in the Earth's gravitational field. See also: gravimeter.

gravity
 * a. The force by which substances are attracted to each other, or fall to Earth. See also: law of gravitation.

b. The effect on any body in the universe of the inverse-square-law attraction between it and all other bodies and of any centrifugal force that may act on the body because of its motion in an orbit. c. The force exerted by the Earth and by its rotation on unit mass, or the acceleration imparted to a freely falling body in the absence of frictional forces. d. A general term for API gravity or Baume gravity of crude oil.

gravity anomaly
 * The difference between the observed value of gravity at a point and the theoretically calculated value. It is based on a simple gravity model, usually modified in accordance with some generalized hypothesis of variation in subsurface density as related to surface topography.

gravity balance
 * Sensitive weighing system in which a beam rides on a fulcrum, and supports a load of unknown weight at one end which is counterbalanced by known weights at the other end.

gravity bar
 * A 5 ft (1.5 m) length of heavy half-round rod forming the link between the wedge-orienting coupling and the drill-rod swivel coupling on an assembled Thompson retrievable borehole-deflecting wedge.

gravity-bar screen
 * See: grizzly.

gravity classifying
 * The grading of ores into different sorts and the separation of waste from coal by the difference in the specific gravity of the minerals to be separated.

gravity concentration
 * Separating grains of minerals by a concentration method operating by virtue of the differences in density of various minerals; the greater the difference in density between two minerals, the more easily they can be separated by gravity methods. The laws of free and hindered settling are important in the theory of gravity concentration.

gravity conveyor
 * Continuous belt, system of rollers, or inclined chute down which loaded material gravitates without the application of power. See also: roller conveyor; wheel conveyor.

gravity corer
 * conditions. The corer weighs about 650 lb (294 kg) in air and consists essentially of a shaft, weights, and coring tube.

b. An oceanographic corer that penetrates the ocean floor solely by its own weight. It is less efficient than a piston corer. There are several varieties, including the Phleger corer and the free corer.

gravity-discharge conveyor elevator
 * A type of conveyor using gravity-discharge buckets attached between two endless chains and which operate in suitable troughs and casings in horizontal, inclined, and vertical paths over suitable drive, corner, and takeup terminals. Syn: bucket elevator. See: V-bucket conveyor elevator.

gravity-discharge conveyor-elevator bucket
 * An elevator bucket designed to contain material on vertical lifts and scrape material along a trough on horizontal runs. Discharge is effected by gravity.

gravity equipotential surface
 * See: equipotential surface.

gravity fault
 * See: normal fault.

gravity feed
 * Applicable when the weight of the drill rods is great enough to impose an adequate pressure on a bit to make it cut properly.

gravity gradiometer
 * An instrument for measuring the gradient of gravity.

gravity haulage
 * A system of haulage in which the set of full cars is lowered at the end of a rope, and gravity force pulls up the empty cars, the rope being passed around a sheave at the top of the incline. The speed of the haulage is controlled by a band brake on the sheave. See also: brake incline; underground haulage. Syn: jig haulage; self-act.

gravity inclines
 * Openings made in the direction of the dip of the deposit. The gradient of the gravity incline is determined by the dip of the deposit. The ore mined is transported through them, usually to the next lower level drive.

gravity instruments
 * Devices for measuring the gravitational force or acceleration or its gradient at any point. They are of three principal types: (1) a static type in which a linear or angular displacement is observed or nulled by an opposing force, (2) a dynamic type in which the period of oscillation is a function of gravity and is the quantity directly observed, or (3) a gradient-measuring type, for example, Eotvos torsion balance.

gravity meter
 * a. Sensitive device for measuring gravitational variations.

b. See: gravimeter.

gravity plane
 * A tramline laid at such an angle that full skips running downhill will pull up the empties.

gravity plane rope haulage
 * See: self-acting rope haulage.

gravity prospecting
 * Mapping the force of gravity at different places with a gravimeter (gravity meter) to determine differences in specific gravity of rock masses, and, through this, the distribution of masses of different specific gravity.

gravity railroad
 * A railroad in which the cars descend by their own weight; an inclined railroad.

gravity road
 * Any road on which cars will descend by gravity.

gravity roller conveyor
 * See: roller conveyor.

gravity screen
 * A perforated steel plate, set at an angle, over which large coal or other material slides by gravity to effect a primary classification.

gravity separation
 * Separation of mineral particles, with the aid of water or air, according to the differences in their specific gravities.

gravity solution
 * A solution used to separate the different mineral constituents of rocks by their specific gravities, as the solution of mercuric iodide in potassium iodide having a maximum specific gravity of 3.19.

gravity stowing
 * A method of stowing in inclined conveyor faces, in which the material is brought into the upper gate (usually the tailgate) and arranged to slide down on trays which are moved forward as each track is filled.

gravity takeup
 * See: belt tensioning device.

gravity wheel conveyor
 * See: wheel conveyor.

gray antimony
 * See: stibnite.

grayband
 * A variety of sandstone for sidewalks; flagstone. See also: flagstone.

gray cast iron
 * A cast iron that gives a gray fracture due to the presence of flake graphite; often called gray iron. See also: iron..

gray cobalt
 * See: cobaltite; smaltite.

gray copper
 * See: tetrahedrite.

gray copper ore
 * See: tennantite; tetrahedrite.

gray hematite
 * See: specularite.

gray iron
 * a. Pig iron or cast iron in which nearly all the carbon not included in pearlite is present as graphitic carbon. See also: mottled iron; white iron.

b. Iron that exhibits a gray fracture surface because fracture occurs along the graphite plates (flakes); it is the result of stable solidification.

grayite
 * A thorium phosphate containing a little lead, calcium, and minor uranium and rare earths; gives an X-ray pattern like that of rhabdophane, and when heated above 850 degrees C, a monazite-type pattern.

Gray-King test
 * Method of assessing the coking property of coal; 20 g is heated in a silica tube to 600 degrees C and the residual product is compared with a standard series ranging from noncoking (type A) to highly coking (G), all of which have the same volume as the original. Cokes that expand (swell) on coking receive a subscript indicating the degree of swelling.

gray manganese ore
 * See: manganite; pyrolusite.

graywacke
 * An old rock name that has been variously defined but is now generally applied to a dark gray, firmly indurated, coarse-grained sandstone that consists of poorly sorted, angular to subangular grains of quartz and feldspar, with a variety of dark rock and mineral fragments embedded in a compact clayey matrix having the general composition of slate and containing an abundance of very fine-grained illite, sericite, and chloritic minerals. Graywacke is abundant within the sedimentary section, esp. in the older strata, usually occurring as thick, extensive bodies with sole marks of various kinds and exhibiting massive or obscure stratification in the thicker units but marked graded bedding in the thinner layers. It generally reflects an environment in which erosion, transportation, deposition, and burial were so rapid that complete chemical weathering did not occur, as in an orogenic belt where sediments derived from recently elevated source areas were poured into a geosyncline. Graywackes are typically interbedded with marine shales or slates, and associated with submarine lava flows and bedded cherts; they are generally of marine origin and are believed to have been deposited by submarine turbidity currents. CF: arkose; subgraywacke. Also spelled: greywacke; grauwacke.

graywether
 * One of numerous fragments or blocks of sandstone and conglomerate, covering large tracts in Dorsetshire and Wiltshire, England, supposed to be remnants of decomposed Tertiary strata. Also called druidical stone; sarsen stone; saracen stone. Syn: sarsen stone.

grease
 * a. A semisolid form of lubricant, composed of emulsified mineral oil and soda or lime soap. Additives may be incorporated for special purposes, for example, colloidal graphite.

b. This term should be applied only to fatty or oily matter of animal origin, but mixtures of mineral oil with lime and soda soaps constitute well-known lubricating greases. c. Term used in the flotation process. d. As used in engineering for lubrication or protection of metal surfaces, grease is an emulsified oil or saturated fatty acid combined with a suitable alkaline base to form a soap. e. Thick oil. f. A solid or semisolid mixture of oil with soap or other fillers.

greased-deck concentration
 * A process in which separation is based on selective adhesion of some grains (diamonds) to quasi-solid grease with adhesion of other grains to water.

greaser
 * a. A person who oils or greases the mine cars.

b. An automatic apparatus that greases the axles of skips as they pass.

grease stone
 * A name for steatite or soapstone.

grease table
 * An apparatus for concentrating minerals, such as diamonds, which adhere to grease. It usually is a shaking table coated with grease or wax over which an aqueous pulp is flowed.

greasing truck
 * An electrically driven service vehicle to transport greases and oil for servicing the underground mine machinery. It may include a compressor, air storage tank, and fittings to place lubricant at the proper points in the mining machinery.

greasy
 * Applied to the luster of minerals. Having the luster of oily glass, as elaeolite.

greasy blaes
 * Scot. See: creeshy.

greasy feel
 * Some minerals or rocks are greasy or soapy to the touch, e.g., talc, graphite, steatite, or soapstone.

greasy gold
 * See: fine gold.

greasy luster
 * As if covered with a thin film of oil or grease, e.g., nepheline, some diamond crystals, and some varieties of serpentine.

greasy quartz
 * See: milky quartz.

Great Falls converter
 * A pear-shaped vessel that resembles the Bessemer converter. It has been largely supplanted by the cylindrical (Peirce-Smith) type converter.

Greathead shield
 * A tunneling device invented by J. H. Greathead, first used in London in 1869, and still widely used today. His invention included a circular cutting edge forced through the ground by hydraulic jacks, a cast-iron lining assembled by bolts, and grouting behind the lining with the aid of compressed air and a special mixer.

great salt
 * Salt in large lumps or crystals.

greave
 * See: ditch.

green acids
 * Mixed sulfonation products from oil refinery cracking processes; used in detergency and as main constituent of a series of flotation agents chiefly concerned with the concentration of iron minerals. Also refers to the initial solution generated from the acceleration of phosphate concentrate.

greenalite
 * A monoclinic mineral, (Fe (super 2+) ,Fe (super 3+) ) (sub 2-3) Si (sub 2) O (sub 5) (OH) (sub 4) ; kaolinite-serpentine group; forms green granules in the taconite of the Mesabi Range, MN, and the Gogebic iron formation of northern Wisconsin.

greenalite rock
 * A dull, dark green rock, uniformly fine-grained with conchoidal fracture, containing grains of greenalite in a matrix of chert, carbonate minerals, and ferruginous amphiboles.

Greenawalt process
 * A system of sintering powdery metalliferous ores.

Greenburg-Smith impinger
 * A dust-sampling apparatus evolved by the U.S. Bureau of Mines that makes use of the principle of impingement of the dust-laden air at high velocity on a wetted glass surface, together with that of bubbling the air through a liquid medium. See also: midget impinger.

green chalcedony
 * Usually some cryptocrystalline variety of quartz stained green. Also may be chalcedony of natural green color. See also: chrysoprase.

green charge
 * A mixture of ingredients for gunpowder before the intimate mixing in the incorporating mill.

green copperas
 * The mineral melanterite, hydrous ferrous sulfate, Fe (super 2+) SO (sub 4) .7H (sub 2) O . Syn: green vitriol.

green hole
 * A furnace taphole in which clay is not properly set, and through which the drill may break and let iron out unexpectedly.

green iron ore
 * See: dufrenite.

greenlandite
 * See: columbite.

Greenland spar
 * See: cryolite.

green lead ore
 * See: pyromorphite.

green marble
 * See: verde antique.

green mud
 * A deep-sea terrigenous deposit characterized by the presence of a considerable proportion of glauconite and CaCO (sub 3) in variable amounts up to 50%.

greenockite
 * A hexagonal mineral, 2[CdS] ; forms earthy incrustations and coatings on sphalerite and other zinc ores; rarely in amygdules. See also: xanthochroite.

greenovite
 * A rose-colored variety of titanite (sphene) containing up to 3% MnO.

green roof
 * A miner's term for a roof that has not broken down or shows no sign of taking weight.

green salt
 * a. Uranium tetrafluoride.

b. A wood preservative consisting of copper, arsenic, and chromium compounds.

greensand
 * a. An unconsolidated marine sediment consisting largely of dark greenish grains of glauconite, often mingled with clay or sand (quartz may form the dominant constituent), found between the low-water mark and the inner mud line. The term is loosely applied to any glauconitic sediment.

b. A sandstone consisting of greensand that is often little or not at all cemented, having a greenish color when unweathered but an orange or yellow color when weathered, and forming prominent deposits in Cretaceous and Eocene beds (as in the Coastal Plain areas of New Jersey and Delaware); specif. either or both of the Greensands (Lower and Upper) of the Cretaceous System in England, whether containing glauconite or not. Syn: glauconite; glauconitic sandstone.

greensand marl
 * A marl containing sand-size grains of glauconite.

greenschist
 * A schistose metamorphic rock whose green color is due to the presence of chlorite, epidote, or actinolite. CF: greenstone.

greenstone
 * a. A field term applied to any compact dark-green altered or metamorphosed basic igneous rock (e.g., spilite, basalt, gabbro, diabase) that owes its color to the presence of chlorite, actinolite, or epidote. CF: greenschist.

b. See: nephrite. c. An informal name for a greenish gemstone, such as fuchsite or chiastolite. d. Compact, igneous rocks that have developed enough chlorite in alteration to give them a green cast. They are mostly diabases and diorites. Greenstone is partially synonymous with trap. It is often used as a prefix to other rock names. The term is used frequently when no accurate determination is possible. e. Includes rocks that have been metamorphosed or otherwise so altered that they have assumed a distinctive greenish color owing to the presence of one or more of the following minerals: chlorite, epidote, or actinolite. f. Freshly quarried stone containing quarry water. g. Can. Generalized name given to Precambrian lavas.

green top
 * Freshly exposed roof that is unknown in quality.

green vitriol
 * A ferrous sulfate; copperas. Also called martial vitriol. See also: melanterite; green copperas.

Greenwell formula
 * A formula used for calculating the thickness of tubbing: T = 0.03 + HD/50,000, where T is the required thickness of tubbing in feet, H is the vertical depth in feet, D is the diameter of the shaft in feet, and 0.03 is an allowance for possible flaws or corrosion.

greet stone
 * A term used in Yorkshire, England, for a coarse-grained or gritty sandstone.

greigite
 * An isometric mineral, Fe (super 2+) Fe (super 3+) (sub 2) S (sub 4) ; linaeite group; in minute grains and crystals in clays in the Kramer-Four Corners area, San Bernadino County, CA.

greisen
 * A pneumatolytically altered granitic rock composed largely of quartz, mica, and topaz. The mica is usually muscovite or lepidolite. Tourmaline, fluorite, rutile, cassiterite, and wolframite are common accessory minerals. See also: greisenization.

greisenization
 * A process of hydrothermal alteration in which feldspar and muscovite are converted to an aggregate of quartz, topaz, tourmaline, and lepidolite (i.e., greisen) by the action of water vapor containing fluorine.

grenatite
 * See: leucite; staurolite.

grenz
 * Horizons in coalbeds resulting from temporary halting of the accumulation of vegetal material. They are frequently marked by a bed of clay or sand.

greve
 * A ditch or trench.