Appendix:Dictionary of Mining, Mineral, and Related Terms/G/4

grid
 * a. Two sets of uniformly spaced parallel lines, intersecting at right angles, by means of which the surface of an area is divided into squares when a checkerboard placement of boreholes is desired. Elevations may be taken at line intersections. CF: checkerboarded.

b. In surveying, a triangulation scheme that covers its area with a network of acute-angled triangles drawn between mutually visible points. c. A grated opening, as in a mining sieve. d. A network composed of two sets of uniformly spaced parallel lines, usually intersecting at right angles and forming squares, superimposed on a map, chart, or aerial photograph, to permit identification of ground locations by means of a system of coordinates and to facilitate computation of direction and distance. The term is frequently used to designate a plane-rectangular coordinate system superimposed on a map projection, and usually carries the name of the projection; e.g., Lambert grid. Not to be confused with graticule. e. A systematic array of points or lines; e.g., a rectangular pattern of pits or boreholes used in alluvial sampling.

gridaw
 * The framing at the top of a shaft for the pulley wheels or sheaves for the hoisting rope.

grid azimuth
 * The angle at a given point in the plane of a rectangular coordinate system between the central meridian, or a line parallel to it, and a straight line to the azimuth point.

gridiron twinning
 * See: crossed twinning.

Griffin mill
 * A grinding mill in which a vertically suspended rolling disk rotates, and under the influence of centrifugal force bears on ore passing between it and a stationary bowl, crushing the passing ore on its way to a peripheral discharge. Syn: pendulum mill.

griffithite
 * A ferroan variety of saponite.

Griffith's theory
 * Griffith's theory of failure is based on the assumption that the low order of tensile strength in common materials is due to the presence of small cracks or flaws. Actual stresses may occur around these flaws, which are of the order of magnitude of molecular cohesion values, while the average tensile strength may be quite low. 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.

grike
 * A joint fracture in limestone, widened by solution.

grindability
 * a. Grindability of coal, or the ease with which it may be ground fine enough for use as pulverized fuel, is a composite physical property embracing other specific properties, such as hardness, strength, tenacity, and fracture.

b. The effect produced on representative pieces of ore by applying standard methods of comminution, assessed comparatively in terms of size reduction and power used. c. Relative ease of grinding, analogous to machinability.

grindability index
 * A measure of the grindability of a material under specified grinding conditions, expressed in terms of volume of material removed per unit volume of wheel wear.

grinder-mill operator
 * a. In ore dressing, smelting, and refining, one who mixes raw materials, such as bauxite, lime, soda ash, and starch, entering the alumina-extraction process to produce a slurry of proper chemical composition, using a ball mill. Also called ball mill operator.

b. In ore dressing, smelting, and refining, one who grinds ore and separates fine particles from coarse particles in a ball mill and classifier arranged in continuous series.

grinders' asthma
 * Disease of the lungs consequent upon inhaling the metallic dust produced in grinding operations. Also called grinders' rot; phthisis.

grinding
 * a. Size reduction into fine particles; comminution. See also: dry grinding; wet grinding.

b. The process of erosion by which rock fragments are worn down, crushed, sharpened, or polished through the frictional effect of continued contact and pressure by larger fragments. c. Abrasion by rock fragments embedded in a glacier and dragged along the bedrock floor.

grinding aid
 * An additive to the charge in a ball mill or rod mill to accelerate the grinding process; the additive has surface-active or lubricating properties. Grinding aids find particular use in the grinding of portland cement clinker but, in the United Kingdom, their use is precluded by the conditions laid down in British Standard 12.

grinding cycle
 * The sequence of operations in grinding a material, including, for example, the screening of the primary product and the recirculation of the screen overflow.

grinding mill
 * A machine for the wet or dry fine crushing of ore or other material. The three main types are the ball, rod, and tube mills. The mill consists of a rotating cylindrical drum; the ore enters one hollow trunnion and the finished product leaves the other. Modern practice indicates ball mill feeds of 1/2 in, 3/4 in, and 1 in (1.27 cm, 1.91 cm, and 2.54 cm) for hard, medium, and soft ores respectively and the products range from 35 to 200 mesh and finer. See also: open-circuit mill.

grinding pebbles
 * Pebbles, usually of chert or quartz, used for grinding in mills where contamination with iron must be avoided.

griotte marble
 * A French marble of a beautiful red color and often variegated with small dashes of purple and spots or streaks of white, as in the variety locally known as griotte oeil de perdrix from the French Pyrenees.

gripe
 * A strap brake or ribbon brake on a hoisting apparatus.

gripping hole
 * One whose direction is inclined away from the adjacent free face, or may be defined as one whose width is greater at the toe than at the heel.

gripping shot
 * A shot so placed that the point or inner end of the hole is considerably farther from the face of the coal to be broken than is the heel or outer end of the hole. See also: shot.

grip the rib
 * When a cut is so made by a mining machine or a shot is so placed by a miner that the cut or shot enters the coal beyond the proper line of the rib, it is said to grip the rib.

grisley
 * See: grizzly.

grit
 * a. A coarse-grained sandstone, esp. one composed of angular particles; e.g., a breccia composed of particles ranging in diameter from 2 to 4 mm.

b. A sand or sandstone made up of angular grains that may be coarse or fine. The term has been applied to any sedimentary rock that looks or feels gritty on account of the angularity of the grains. c. A sandstone composed of particles of conspicuously unequal sizes (including small pebbles or gravel). d. A sandstone with a calcareous cement. The term has been applied incorrectly to any nonquartzose rock resembling a grit; e.g., pea grit or a calcareous grit. e. A small particle of a stone or rock; esp. a hard, angular granule of sand. Also, an abrasive composed of such granules. f. The structure or grain of a stone that adapts it for grinding or sharpening; the hold of a grinding substance. Also, the size of abrasive particles, usually expressed as their mesh number. g. An obsolete term for sand or gravel, and for earth or soil. The term is vague and has been applied widely with many different connotations. Etymol: Old English greot, gravel, sand.

grit collector
 * An adaptation of any of several types of conveyors used for removing heavy solids from settling tanks or basins. See also: bucket elevator; flight conveyor; reciprocating flight conveyor; screw conveyor.

grit number
 * See: mesh number.

gritting
 * In quarrying, a process that gives a smoother surface than rubbing. It is accomplished with silicon carbide or aluminum oxide abrasive bricks attached to revolving buffer heads.

grizzly
 * a. A device comprised of fixed or moving bars, disks, or shaped tumblers or rollers for the coarse screening or scalping of bulk materials. See also: bar grizzly; grizzly chute; live roll grizzly. Syn: grisley; gravity-bar screen.

b. A series of iron or steel bars spaced so as to size, sort, or separate the bulk material as it falls into the ore chutes. c. A rugged screen for rough sizing at a comparatively large size (e.g., 6 in or 15.2 cm); it can comprise fixed or moving bars, disks, or shaped tumblers or rollers.

grizzly chute
 * A chute with a bar grizzly which separates the fine from the coarse material as it passes through the chute. See also: grizzly.

grizzly man
 * See: grizzly worker.

grizzly worker
 * In metal mining, a laborer who works underground at a grizzly over a chute or raise heading to a storage bin or haulage level, dumping ore from cars through the grizzly, and breaking oversized lumps with a sledge hammer so that they will pass through the grizzly. Also called draw man; grizzly man.

grog fire clay mortar
 * Raw fireclay mixed with calcined fireclay, or with broken fireclay brick, or both, all ground to suitable fineness.

groove
 * a. The long, tapered, half-round slot in the deflection wedge that acts as a guide in directing the bit to follow a new course in deflecting a borehole. Any of the spiral depressions on a cylindrical object, such as the spiral depression on the surface of fluted core or the rifling in a gun barrel.

b. Derb. The place where a miner is working. See also: grove. c. A mine, from the German, grube.

grooved drum
 * Drum having a grooved surface to support and guide a rope.

groover
 * N. of Eng. A miner.

groove sample
 * See: channel sample.

groroilite
 * A nearly black earthy manganese or wad, streaked with dark red markings, occurring in parts of Europe.

gross calorific value
 * a. The heat produced by combustion of unit quantity of a solid or liquid fuel when burned at constant volume in an oxygen bomb calorimeter under specified conditions, with the resulting water condensed to a liquid.

b. The amount of heat liberated by the complete combustion of unit weight of coal under specified conditions; the water vapor produced during combustion is assumed to be completely condensed. c. At constant pressure, the number of heat units that would be liberated if unit quantity of coal or coke was burned in oxygen at constant pressure in such a way that the heat release was equal to the sum of the gross calorific value at constant volume and the heat equivalent of the work that would have been done by the atmosphere under isothermal conditions had the pressure remained constant. d. At constant volume, the number of heat units measured as being liberated per unit quantity of coal or coke burned in oxygen saturated with water vapor in a bomb under standard conditions, the residual materials in the bomb being taken (suitable corrections having been made) as gaseous oxygen, carbon dioxide, sulfur dioxide, nitrogen, liquid water in equilibrium with its vapor and saturated with carbon dioxide, and ash. Syn: gross heat of combustion.

gross cut
 * The total amount of excavation in a road or a road section, without regard to fill requirements.

gross heat of combustion
 * See: gross calorific value.

gross recoverable value
 * The part of the total metal recovered multiplied by the price. The proportion recovered varies with the ore and the method used. See also: net unit value.

gross ton
 * The long ton of 2,240 avoirdupois pounds.

grossular
 * An isometric mineral, 8[Ca (sub 3) Al (sub 2) Si (sub 3) O (sub 12) ], rarely pure; garnet group; crystallizes in dodecahedra and trapezohedra; varicolored; in metamorphosed calcareous rocks and skarns. Formerly called grossularite. Syn: cinnamon stone.

gross unit value
 * The weight of metal per ton (long or short ton), as determined by assay or analysis, multiplied by the market price of the metal. See also: net unit value.

grothite
 * A variety of titanite containing yttrium or cerium.

grouan
 * See: growan.

ground
 * a. Rock at the side of a lode; country rock.

b. The mineralized deposit and the rocks in which it occurs, e.g., payground, payable reef; barren ground, rock without value. c. A ground is a conducting connection, whether intentional or accidental, between an electrical circuit or equipment and either the Earth or some conducting body serving in place of the Earth. Also called earth.

ground boss
 * a. A mine foreman.

b. See: mine captain.

ground control
 * a. Maintaining rock mass stability by controlling the movement of excavations in the ground, which can be either rock or soil.

b. Accurate data on the horizontal and/or vertical positions of identifiable ground points so that they may be recognized on aerial photographs.

grounded circuit
 * Electrical system earthed at key points to ensure a common potential and eliminate danger to personnel.

grounded power conductor
 * An insulated or bare cable that constitutes one side of a power circuit and normally is connected to ground. It differs from a ground wire in that a grounded power conductor normally carries the load current while the equipment it serves is in operation.

ground fault
 * An electrical contact between part of the blasting circuit and earth.

ground geophysical anomaly
 * A geophysical anomaly that is mapped instrumentally at the surface of the ground.

grounding transformer
 * See: zigzag transformer.

ground log
 * A device for determining the course and speed made good over the ground in shallow water, consisting of a lead or weight attached to a line. The lead is thrown overboard and allowed to rest on the bottom. The course being made good is indicated by the direction the line tends, and the speed by the amount of line paid out in unit time.

ground magnetometer
 * A magnetometer primarily suitable for making observations of magnetic field intensity on the surface of the Earth.

groundmass
 * a. The material between the phenocrysts of a porphyritic igneous rock. It is relatively finer grained than the phenocrysts and may be crystalline, glassy, or both. CF: mesostasis. Syn: matrix.

b. A term sometimes used for the matrix of a sedimentary rock.

ground movement
 * a. Subsidence due to the caving or collapse of underground workings.

b. Displacement of ground along a fault, bedding plane, or joint caused by mining-induced stress.

ground noise
 * Seismic disturbance of the ground not caused by the shot.

ground plate
 * a. A bedplate supporting railroad sleepers or ties.

b. In electricity, a metal plate in the ground forming the earth connection of a metallic circuit.

ground pressure
 * a. The pressure to which a rock formation is subjected by the weight of the superimposed rock and rock material or by diastrophic forces created by movements in the rocks forming the Earth's crust. Such pressures may be great enough to cause rocks having a low compressional strength to deform and be squeezed into and close a borehole or other underground opening not adequately strengthened by an artificial support, such as casing or timber. Also called rock pressure. CF: bottom-hole pressure.

b. The weight of a machine divided by the area in square inches of the ground directly supporting it.

ground prop
 * The puncheon between the lowest frame and a foot block in a timbered excavation, used to support the weight of the timbering.

ground roll
 * a. Low-frequency, low-velocity interface waves encountered in seismic prospecting commonly arising from the ground-air interface, in which case they are known as Rayleigh waves. Ground roll can completely mask desired signals, and means to minimize it commonly must be used.

b. Seismic surface wave generated by the shot. See also: ground waves.

ground sluice
 * a. A channel or trough in the ground through which auriferous earth is sluiced for placer mining.

b. To wash down a bank of earth with a stream of water.

ground sluicing
 * To strip ground downslope by means of a directed stream of water to excavate placer material and transport it to a riffled trough in which the valuable mineral is recovered. CF: hydraulicking.

ground spears
 * Wooden rods (one on each side of the pump) by which a sinking pump is suspended.

ground vibrations
 * See: blasting vibrations.

ground water
 * a. That part of the subsurface water that is in the zone of saturation, including underground streams.

b. Loosely, all subsurface water as distinct from surface water. Also spelled: groundwater; ground-water. Syn: subterranean water; underground water.

ground-water discharge
 * The return of ground water to the surface.

ground-water hydrology
 * See: geohydrology.

ground-water level
 * a. See: water table.

b. The elevation of the water table at a particular place or in a particular area, as represented by the level of water in wells or other natural or artificial openings or depressions communicating with the zone of saturation. Syn: ground-water table.

ground-water lowering
 * The process of lowering the water table so that an excavation can be carried out in the dry. This is done by means of well points.

ground-water province
 * An area or region in which geology and climate combine to produce ground-water conditions consistent enough to permit useful generalizations.

ground-water surface
 * See: water table.

ground-water table
 * See: water table; ground-water level.

ground-water tracers
 * The water seeping into shallow workings or shafts may be traced to the surface source by means of tracer dyes or salts. These substances, however, may be leached out of the water by the soil or strata. Some radioactive isotopes are better tracers because of the high sensitivity with which they can be detected. Tritium, an isotope of hydrogen, is unique because it can be used to label the actual water molecule to be traced and is not chemically removed by the strata.

ground waves
 * Vibrations of soil or rock. See also: ground roll.

ground wire
 * A bare or insulated cable used to connect the metal frame of a piece of equipment to the mine track or other effective grounding medium.

group
 * a. The lithostratigraphic unit next in rank above formation, consisting partly or entirely of named formations. A group name combines a geographic name with the term "group," and no lithic designation is included; e.g., San Rafael Group.

b. A stratigraphic sequence that will probably be divided in whole or in part into formations in the future. See also: analytic group. c. A general term for an assemblage or consecutive sequence of related layers of rock, such as of igneous rocks or of sedimentary beds. d. A more or less informally recognized succession of strata too thick or inclusive to be considered a formation. e. A number of shots sufficiently close together to be treated in common in respect to preparation for firing.

group level
 * a. A main haulageway drive built in the solid rock underlying the group of seams that it has to serve, or in the floor of a thick deposit. It is preferable to construct the main haulageway as a subdeposit drive, because drives in the deposit suffer from pressure as soon as mining has progressed a certain distance.

b. Syn: subdeposit level.

grout
 * a. A pumpable slurry of neat cement or a mixture of neat cement and fine sand, commonly forced into boreholes or crevices in a rock to prevent ground water from seeping or flowing into an excavation, to seal crevices in a dam foundation, or to consolidate and cement together rock fragments in a brecciated or fragmented formation. Also called cement grout.

b. A cementitious component of high water-cement ratio, permitting it to be poured or injected into spaces within masonry walls. It consists of portland cement, lime, and aggregate, and is often formed by adding water to mortar. c. The act or process of injecting a grout into a rock formation through a borehole or crevice. d. Applied to waste material of all sizes obtained in quarrying stone. e. A coarse kind of plaster or cement usually studded with small stones after application, sometimes used for coating walls of a building.

grout core
 * Core obtained by drilling into and through formations into which grout has been injected and allowed to set.

grout curtain
 * An area into which grout has been injected to form a barrier around an excavation or under a dam through which ground water cannot seep or flow.

grouter
 * a. In the stonework industry, a laborer who maintains the floors, equipment, machinery, and yard in a clean and unobstructed condition, using shovels, brooms, buckets, and wheelbarrows to collect and remove stone scraps, dirt, and debris to dump for disposal or to remove steel shot from under gangsaws and store it in suitable containers to be washed and reused. Also called mucker.

b. See: box loader.

grout hole
 * A borehole drilled for the express purpose of using it as a means by which grout may be injected into the rock surrounding the borehole. CF: consolidation hole.

grouting
 * The injection of grout into fissured, jointed, or permeable rocks in order to reduce their permeability or increase their strength.

grout injection
 * An act or process of forcing grout into crevices in rock formations, usually through a borehole, by pressure pumps.

grout injector
 * A machine that mixes the dry ingredients for a grout with water and injects it, under pressure, into a grout hole. CF: grout machine.

groutite
 * An orthorhombic mineral, MnO(OH) ; trimorphous with manganite and feitknechtite; in brilliant submetallic to adamantine wedge-shaped crystals in the banded iron formations of the Cuyuna Range, MN.

grout machine
 * A mechanism by which grout may be pressure-injected into a grout hole. CF: grout injector.

grove
 * a. Eng. A drift or adit driven into a hillside from which coal is worked. See also: groove.

b. Corn. Mine; bal.

grovesite
 * A former name for pennantite.

growan
 * a. An old English term for a coarse-grained granite, grit, or sandstone.

b. A grus developed by the disintegration of a granite. Syn: grouan. See: grus.

growler board
 * A notched or fingered plank or light timber used to align ends of pipe being screwed together, as when laying a waterline.

grow-on
 * Quarrymen's term to designate the place where the sheet structure dies out, or the place where two sheets appear to grow onto one another.

growth
 * a. An increase in dimensions of a compact that may occur during sintering (converse of shrinkage).

b. As applied to cast iron, the tendency to increase in volume when repeatedly heated and cooled. c. See: make of water.

grubbing
 * The removal of the root system incident to the surface growth.

grube
 * Ger. A mine.

grub saw
 * A saw made from a coarsely notched blade of soft iron and provided with a wooden back; it is used, with sand, for sawing stone by hand.

grubstake
 * In the Western United States, supplies or funds furnished to a mining prospector on promise of a share in his discoveries. So called because the lender stakes or risks provisions so furnished.

grubstake contract
 * An agreement between two or more persons to locate mines upon the public domain by their joint aid, effort, labor, or expense, and each is to acquire by virtue of the act of location such an interest in the mine as agreed upon in the contract.

grueso
 * Sp. Lump ore. The term is used at the mercury mines in California.

gruff
 * Eng. A pit or shaft.

grunching
 * Blasting coal out of the solid face as opposed to blasting coal that has been undercut by hand or by coal cutter.

grundy
 * Granulated pig iron used in making granulated steel.

grunerite
 * A monoclinic mineral, (Fe,Mg) (sub 7) Si (sub 8) O (sub 22) (OH) (sub 2) ; amphibole group, with Mg/(Mg+Fe)=0-0.3 ; forms series with cummingtonite and with magnesiocummingtonite; fibrous or needlelike, commonly in radial aggregates; characteristic of iron formations in the Lake Superior and Labrador Trough regions. Also spelled gruenerite.

grunter
 * A hooked rod to aid in supporting a crucible.

grus
 * The fragmental products of in situ granular disintegration of granite and granitic rocks. Syn: grush; residual arkose; growan. Etymol: Ger. Grus, grit, fine gravel, debris. Also spelled: gruss.

grush
 * See: grus.

G stone
 * A name which has been used for pyrophyllite. See also: pyrophyllite.

guag
 * Corn. A place from which the ore has been extracted. Syn: gunis.

guardian angel
 * A warning device affixed to the roof or back of a mine that automatically displays a visual indication when rock displacement begins. See also: safety light.

guard magnet
 * Permanent magnet or electromagnet used in crushing system to arrest or remove tramp iron ahead of the crushing machinery.

guardplate
 * A plate in front of an iron furnace, covering the taphole through which the slag is drawn out.

guard screen
 * See: oversize control screen.

gublin bat
 * A black, fissible substance, an iron ore, in which a bituminous shivery earth abounds.

gudgeon
 * a. The bearing of a shaft, esp. when made of a separate piece.

b. A metallic journal piece set into the end of a wooden shaft. A reinforced bushing or a thrust-absorbing block.

gudmundite
 * A silver-white to steel-gray sulfantimonide of iron, FeSbS. Isomorphous with arsenopyrite; elongated crystals; orthorhombic. From Gudmundstrop, Sweden.

guest element
 * a. A trace element substituting a common element in a rock mineral.

b. See: trace element.

gug
 * Som. A self-acting inclined plane underground; sometimes called a dip incline.

gugiaite
 * A mineral, Ca (sub 2) BeSi (sub 2) O (sub 7), tetragonal, in skarn rocks near Gugia (presumably in China). A member of the melilite family near meliphane but containing little sodium or fluorine; an unnecessary name. Named from the locality. See also: meliphanite.

guhr
 * a. A white (sometimes red or yellow), loose, earthy, water-laid deposit of a mixture of clay or ocher, occurring in the cavities of rocks.

b. See: diatomite.

guide
 * a. A pulley to lead a driving belt or rope in a new direction or to keep it from leaving its desired direction.

b. The tracts that support and determine the path of a skip bucket and skip bucket bail.

guide core
 * See: dummy.

guide fossil
 * Any fossil that has actual, potential, or supposed value in identifying the age of the strata in which it is found or in indicating the conditions under which it lived; a fossil used esp. as an index or guide in the local correlation of strata. CF: index fossil.

guide frame
 * A frame designed to be held rigidly in place by roof jacks or timbers, and with provisions for attaching a shaker conveyor panline to the movable portion of the frame, which can be used to prevent jumping or side movement of the panline.

guide idler
 * An idler roll with its supporting structure so designed that when it is mounted on the conveyor frame it guides the belt in a defined horizontal path, usually by contact with the edge of the belt.

guide pulley
 * A loose pulley used to guide a driving belt past an obstruction or to divert its direction.

guide rod
 * A heavy drill rod coupled to and having the same diameter as a core barrel on which it is used. It gives additional rigidity to the core barrel and helps to prevent deflection of the borehole. Also called core-barrel rod; oversize rod. CF: drill collar.

guide rope
 * See: cage guide.

guide runner
 * A runner driven ahead of other runners to guide them.

guides
 * a. Wood, steel, or wire-rope conductors in a mine shaft, which are engaged by shoes on the cage or skip so as to guide its movement.

b. Timber or metal tracks in a hoisting shaft, which are engaged by shoes on the cage or skip so as to steady it in transit. In collieries rope guides are sometimes used. c. The holes in a crossbeam through which the stems of the stamps in a stamp mill rise and fall. d. A pulley to lead a driving belt or rope in a new direction, or to keep it from leaving its desired direction.

guillies
 * Corn. Worked-out cavities in a mine.

guillotine
 * A machine for breaking iron with a falling weight.

guinea bed
 * War. The shelly, conglomeratic basement limestone bed of the Lower Lias. So called because the stones, if dry, ring when struck. CF: sun bed.

guinea gold
 * Twenty-two carat gold, of which guineas were coined.

gulch
 * A term used esp. in the Western United States for a narrow, deep ravine with steep sides, larger than a gully; esp. a short, precipitous cleft in a hillside, formed and occupied by a torrent, and containing gold (as in California).

Gulf-type (Vacquier) magnetometer
 * A flux gate or saturable reactor type of recording magnetometer. Used primarily in aircraft and there includes means for keeping the measuring element aligned in the direction of maximum intensity (that is, total field). In this case it records variations in the total field regardless of variations in its direction. Sometimes used for establishing the position of the aircraft as well as the magnetometer itself.

gull
 * A structure formed by mass-movement processes, consisting of widened, steeply inclined tension fissures or joints, resulting from lateral displacement of a slide mass and filled with debris derived from above. Primarily a British usage.

gum
 * a. See: gummings.

b. Small coal broken out by a coal cutter. See also: duff. c. Small coal, slack, or duff.

gumbo
 * A term used locally in the United States for a clay soil that becomes sticky, impervious, and plastic when wet.

gumbrine
 * Same as fuller's earth, and similar to floridine from Gumbri, near Kutais, Georgia, Transcaucasia, in the former U.S.S.R.

gum copal
 * See: copal.

gum dynamite
 * Explosive gelatin.

gummer
 * A person who clears the fine coal, gum, or dirt from the undercut made by a coal-cutting machine.

gummings
 * The small coal or dirt produced by the picks of a coal cutter. Syn: gum.

gummite
 * A mixture of yellow or orange secondary uranium oxides formed by alteration of uraninite.

gummy
 * Applicable when rock or formation being drilled produces cuttings and sludge, which tend to fill the waterways of a bit or to adhere massively to the borehole walls or drill-stem equipment. CF: balling formation; sticky.

gun
 * A borehole in which the charge of explosive has been fired with no other effect than to blast off a small amount of material at the mouth of the borehole; also called a bootleg or John Odges. See also: blown-out shot.

gunboat
 * A self-dumping box on wheels, used for raising (or lowering) coal in slopes; a monitor, a skip.

gun drill
 * A drill, usually with one or more flutes and with coolant passages through the drill body, used for deep-hole drilling.

gunis
 * See: guag.

gunite gun
 * A mixture of portland cement, sand, and water applied by pneumatic pressure through a specially adapted hose and used as a fireproofing agent and as a sealing agent to prevent weathering of mine timbers and roadways. Etymol: Gunite, a trademark. To apply gunite; to cement by spraying gunite. See also: Aliva concrete sprayer. l+  \(: �*: ��8��       � ( DICTIONARY TERMS:gunite gun See: cement gun. See: cement gun.

guniting
 * Pneumatically applied portland cement mortar, or gunite. The spraying of mine openings with concrete to provide ground support, present a smooth surface to the air current, and prevent weathering with the mortar. See also: lining; timber preservation; Aliva concrete sprayer.

gunk
 * a. See: rod dope.

b. Any gummy substance that collects inside the working parts and hinders the operation of a machine or other mechanical apparatus. c. A permanent emulsion that forms in liquid-liquid extraction equipment, often containing dust or other solid matter at the core of each globule.

gunned shot
 * Scot. See: blown-out shot.

gunnie
 * a. Corn. In mining, measure of breadth or width, a single gunnie being 3 ft (0.91 m) wide.

b. Corn. The vacant space left where the lode has been removed; a crevice. Plural: gunnies. Also spelled gunniss; gunnice. Syn: house.

gunningite
 * A monoclinic mineral, (Zn,Mn)SO (sub 4) .H (sub 2) O ; kieserite group; as efflorescences on sphalerite from the Keno Hill and Galena Hill area, central Yukon Territory, Canada.

gunning the pits
 * Agitation of the drilling fluid in a pit by forcing a portion of the fluid under pressure through a constricted tube or gun, jetting it into the main body of fluid.

gunniss
 * Corn. See: gunnie.

gun-perforator loader
 * In petroleum production, one who loads explosive powder into gun perforators used in shooting holes through tubings, casings, and earth formations of oil or gas wells to aid in well drilling or producing operations, working either in shop or at well site. Also called the loader; perforator loader. See also: loader.

gunpowder paper
 * Paper spread with an explosive compound. It is rolled up for use in loading.

gunpowder press
 * A press for compacting meal powder before granulating into gunpowder.

Gunter's chain
 * A surveyor's chain that is 66 ft (20 m) long, consisting of a series of 100 metal links each 7.92 in (20.1 cm) long and fastened together with rings. It served as the legal unit of length for surveys of U.S. public lands, but has been superseded by steel or metal tapes graduated in chains and links. Named after Edmund Gunter (1581-1626), English mathematician and astronomer, who invented the device about 1620. Syn: chain; pole chain.

gurhofite
 * A snow-white variety of dolomite, containing a large proportion of calcium.

gurlet
 * a. A mason's pickax having one cutting edge and a point.

b. A pickax having a sharply pointed peen and a bladed peen for cutting.

gurmy
 * A mine level; working.

guss
 * a. A rope used for drawing a basket of coal in a thin seam.

b. Brist. A short piece of rope by which a boy draws a tram or sled in a mine.

gusset
 * A V-shaped cut in the face of a heading.

Gusto multiplow
 * A number of small plows attached to a rope or chain which cut backward and forward on the face. They operate in conjunction with an armored conveyor. See also: multiplow.

Gusto scraper box
 * An arrangement of scraper boxes with cutting knives attached to the face side. See also: scraper box plow.

gut
 * To rob, or extract, only the rich ore of a mine.

gutter
 * a. The lowest and usually richest portion of an alluvial placer. The term is used in Australia for the dry bed of a buried Tertiary river containing alluvial gold. Syn: bottom.

b. A gob heading. c. A drainage trench. d. A small airway made through a goaf or gob. e. In deep lead mining, the lowest portion of a deep lead filled with auriferous wash dirt. f. A channel or gully worn by running water.

guttering
 * a. A channel cut along the side of a mine shaft to conduct the water back into a lodge or sump.

b. A process of quarrying stone in which channels, several inches wide, are cut by hand tools, and the stone block detached from the bed by pinch bars. c. The formation of more or less vertical breaks at or toward the centerline of a roadway, as a consequence of which falls occur along the groove or gutter.

Gutzkow's process
 * A modification of the sulfuric acid parting process for bullion containing large amounts of copper. A large excess of acid is used; the silver sulfate is then reduced with charcoal, or, in the original process, ferrous sulfate.

guy
 * a. A wire line or rope attached to the top of a drill derrick or pole and extending obliquely to the ground, where it is fastened to a deadman or guy anchor. See also: guy line.

b. A rope that holds the end of a boom or spar in place. Syn: guy rope. See also: guy line.

guy anchor
 * The object to which the lower end of a guy is attached. Also called deadman.

guyed
 * Held upright and steadied by one or more guys.

guy line
 * A guy or several guys. See also: guy.

guyot
 * A flat-topped submarine mountain rising from the floor of the ocean like a volcano but planed off on top and covered by an appreciable depth of water.

guy ring
 * A ring on the head block or top of a drill pole, derrick, or tripod to which guys are attached.

guy rope
 * a. A rope holding a structure in a desired position.

b. See: guy.

gyprock
 * a. Massive rock gypsum.

b. A driller's term for a rock of any kind in which he has trouble in making a hole. c. A rock composed chiefly of gypsum.

gypsiferous
 * Containing gypsum. Also spelled gypseous.

gypsification
 * Development of, or conversion into, gypsum; e.g., the hydration of anhydrite.

gypsite
 * See: gypsum.

gypsum
 * A monoclinic mineral, 8[CaSO (sub 4) .2H (sub 2) O] ; colorless to white in crystals, but massive beds may range from red to yellow to brown, gray, or black; the most common natural sulfate; defines 2 on the Mohs hardness scale; commonly associated with rock salt (halite) and anhydrite; forms beds and lenses interstratified with limestone, shale, and clay, esp. in rocks of Permian to Triassic age; also in volcanic fumarolic deposits; an accessory mineral in metalliferous veins. Syn: gypsite.

gypsum plate
 * In polarized-light microscopy, an accessory plate of clear gypsum (replaced by quartz of the appropriate thickness in modern instruments) that gives a first-order red (approx. 1 lambda out of phase for 560 nm) interference color with crossed polars when inserted in the tube with its permitted electric vectors at 45 degrees to those of the polarizer and analyzer. It is used to determine fast and slow directions (electric vectors) of light polarization in crystals under view on the microscope stage by increasing or decreasing retardation of the light. Also called a sensitive-tint plate. CF: accessory plate; quartz wedge. See also: selenite plate. Syn: gips plate.

gyrasphere crusher
 * Heavy-duty fixed path cone crusher; a variant from the standard cone crusher. See also: Symon's cone crusher.

gyratory
 * a. More or less eccentric, as certain rock crushers.

b. A widely used form of rock breaker in which an inner cone rotates eccentrically in a larger outer hollow cone.

gyratory breaker
 * A primary crusher consisting of a vertical spindle, the foot of which is mounted in an eccentric bearing within a conical shell. The top carries a conical crushing head revolving eccentrically in a conical maw. There are three types of gyratories--those that have the greatest movement on the smallest lump, those that have equal movement for all lumps, and those that have greatest movement on the largest lump. Syn: gyratory crusher. See also: cone crusher.

gyratory crusher
 * See: gyratory breaker.

gyrocompass
 * a. A north-seeking form of gyroscope used as a vehicle's or craft's directional reference. Also known as gyroscopic compass.

b. The gyrocompass is used in underground and borehole surveying. Syn: gyroscopic compass; gyrostatic compass.

gyroscopic-clinograph method
 * A method for measuring borehole deviation that photographs time, temperature, and inclination from the vertical on 16 mm film and can take 1,000 readings descending then ascending the hole as a check. The gyroscope maintains the casing on a fixed bearing.

gyroscopic compass
 * a. See: gyrocompass.

b. A magnetic compass whose equilibrium is maintained by the use of gyroscopes.

gyrostatic compass
 * See: gyrocompass.