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

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See: pillar-and-breast.


See: pillar-and-breast.

board coal

Eng. Coal having a fibrous or woody appearance.

board gates

York. Headings driven in pairs generally to the rise, out of which banks or stalls are opened and worked.

board of trade unit

The work done when a rate of working of 1 kW is maintained for 1 h. The British unit of electrical energy; kilowatt-hour. Abbrev: B.O.T. unit.

board run

The amount of undercutting that can be done at one setting of a coal mining machine, usually about 5 ft (1.5 m), without moving forward the board upon which the machine works.


See: bort.


See: bort.


A gold dredge.


a. Aust. A catch placed between the rails of the upline of an incline to stop any runaway trucks. It consists of a bent iron bar, pivoted in such a manner that the downhill end is slightly heavier than the uphill end, which is capable of being depressed by an upcoming truck, but rises above the level of the truck axle as soon as the truck is past. Syn: monkey; monkey chock.

b. A spool or reel.


A volcanic crater or vent.


a. An orebody, or pocket of mineral deposit.

b. See: bit blank. c. The fluidity of a drilling mud expressed in the number of seconds in which a given quantity of mud flows through a given aperture, such as the aperture in a Marsh funnel. d. The term used to indicate the viscosity or fluidity of a lubricating oil; e.g., a heavy-body oil is thick and viscous and a light-body oil is thin and fluid. e. The load-carrying part of a truck or scraper. f. The fatty, inflammable property that makes a coal combustible; e.g., bituminous coal has morebody than anthracite.


A fluoride, Sr (sub 2) Na (sub 2) Al (sub 2) (PO (sub 4) )F (sub 9) , from the Greenland cryolite deposit.

boghead cannel

Cannel coal rich in algal remains. See also: torbanite.

boghead cannel shale

A coaly shale rich in fatty or waxy algae.

boghead coal

a. A variety of bituminous or subbituminous coal resembling cannel coal in appearance and behavior during combustion. It is characterized by a high percentage of algal remains and volatile matter. Upon distillation it gives exceptionally high yields of tar and oil. See also: cannel coal; torbanite; kerosine shale.

b. A nonbanded coal with the translucent attritus consisting predominately of algae, and having less than 5% anthraxylon.


See: torbanite.


a. A rail truck or trolley of low height, used for carrying timber or machine parts underground, or for conveying the dirt hoppit from a sinking pit to the dirt heap. It may also be used as a wagon spotter. See also: timber trolley.

b. A weighted truck run foremost or next to the rope in a train or trip. c. A two-axle driving unit in a truck. Also called tandem drive unit; tandem. d. Also spelled bogey; bogy. e. York. A small truck or trolley upon which a bucket is carried from the shaft to the spoil bank.

bog iron

a. A general term for a soft, spongy, and porous deposit of impure hydrous iron oxides formed in bogs, marshes, swamps, peat mosses, and shallow lakes by precipitation from iron-bearing waters and by the oxidizing action of algae, iron bacteria, or the atmosphere; a bog ore composed principally of limonite that is commonly impregnated with plant debris, clay, and clastic material. It is a poor-quality iron ore, in tubular, pisolitic, nodular, concretionary, or thinly layered bodies, or in irregular aggregates, in level sandy soils, and esp. abundant in the glaciated northern regions of North America and Europe (Scandinavia). Syn: limnite; morass ore; meadow ore; marsh ore; lake ore; swamp ore. CF: goethite.

b. A term commonly applied to a loose, porous, earthy form of "limonite" occurring in wet ground. Syn: bog ore.

bog iron ore

a. Loose, porous form of limonite occurring in wet ground, often mixed with vegetable matter, Fe (sub 2) O (sub 3) .nH (sub 2) O .

b. A deposit of hydrated iron oxides found in swamps and peat mosses. See also: iron ore; lake ore. CF: limnite; limonite. Syn: marsh ore; meadow ore.

bog lime

See: marl.

bog manganese

a. See: earthy manganese; wad.

b. A bog ore consisting chiefly of hydrous manganese oxides; specif. wad formed in bogs or marshes by the action of minute plants.

bog-mine ore

See: bog ore.

bog mine ore

See: bog ore.

bog muck

A vernacular name for peat.

bog oak

Oak immersed in peat bogs, semifossilized and blackened to resemble ebony by iron from the water combining with the tannin of the oak.

bog ore

a. A spongy variety of hydrated oxide of iron and limonite. Found in layers and lumps on level sandy soils that have been covered with swamp or bog. Includes bog iron ore, bog manganese ore, and bog lime, a calcareous deposit of similar origin. See also: brown iron ore.

b. A poorly stratified accumulation of earthy metallic-mineral substances, mainly oxyhydroxides, formed in bogs, marshes, swamps, and other low-lying moist places, by direct chemical precipitation from surface or near-surface percolating waters; specif. "bog iron" and "bog manganese". CF: lake ore. Syn: bog mine ore; bog iron.

bog peat

Peat consisting mainly of mosses.

Bohemian garnet

Yellowish-red gem variety of the garnet pyrope; occurs very commonly in the Mittelgebirge, Czech Republic. See also: pyrope.

Bohemian ruby

A jeweler's name for rose quartz when cut as a gem.


An orthorhombic mineral, aluminum oxyhydroxide [gamma -AlO(OH)]; grayish, brownish, or reddish, in some bauxites and laterites; an ore of aluminum, dimorphous with diaspore. Also spelled boehmite.

bohr magneton

The net magnetic moment arising from electron spins.

boiler burner unit

A boiler designed esp. for gas or oil and sold integrally with the burner.

boiler circulating pump

A pump, usually of the single-stage, single-entry, overhung type, that must have low suction loss and high-temperature features since it draws water directly from the boiler drums at high saturation pressure and temperature.

boiling furnace

A water-jacketed reverberatory furnace for decarbonizing iron by a process in which the carbonic oxide escapes with an appearance of boiling.

boiling point

a. The temperature at which a liquid begins to boil or to be converted into vapor by bubbles forming within its mass. It varies with pressure.

b. The temperature at which a cooling gas becomes a liquid.


Hard calcareous or siliceous nodules of irregular shape, found in the shales and underclays of the Coal Measures. See also: boylom.


See: bole.


Any of several varieties of compact earthy clay (impure halloysite), usually red, yellow, or brown because of the presence of iron oxide, and consisting essentially of hydrous silicates of aluminum or less often of magnesium. It is a waxy decomposition product of basaltic rocks, having the variable composition of lateritic clays. Syn: bolar.


A deep blue pseudoisometric hydrous oxychloride of lead, copper, and silver from Boleo, Lower California. A tetragonal form of percylite.

Boliden gravimeter

An electrical stable gravimeter with a moving system suspended on a pair of bowed springs. The moving system carries electrical condenser plates at each end, one to measure the position of the moving system, the other to apply a balancing force to bring the system to a fixed position. Syn: Lindblad-Malmquist gravimeter.

Bolognan stone

See: Bologna stone.

Bologna spar

See: Bologna stone.

Bologna stone

A nodular, concretionary, or round variety of barite, composed of radiating fibers; phosphorescent when calcined with charcoal. Syn: Bolognian stone; Bolognan stone; Bologna spar.

bolognian stone

See: Bologna stone.


a. A term applied in the desert regions of the Southwestern United States to an extensive flat alluvium-floored basin or depression, into which drainage from the surrounding mountains flows toward a playa or central depression; a basin with internal drainage. Syn: playa basin.

b. A temporary lake, usually saline, formed in a bolson. c. Mex. A pocket of ore. Etymol: Sp., bolson, large purse.

Bolsover experiment

Applied to a method of working by single panels. Single 100-yd (91-m) panels are advanced, leaving 100-yd-wide coal pillars between them. The pillars are then worked on the retreat after the advancing faces have reached a limit line.


A rod used in roof bolting. See also: slot-and-wedge bolt; wedge-and-sleeve bolt.


S. Staff. A short narrow opening made to connect the main workings with the airhead or ventilating drift of a coal mine. Also called bolt.

bolt-hole brush

A special round brush used to remove porcelain enamel bisque from in and around small openings in the ware. See also: brush.


Separation of particles of different sizes by means of vibrating sieves.

Bolton's reagent

a. In oceanography, a silk cloth of very fine and regular mesh, used in the construction of tow nets for the smaller members of the surface fauna.

b. Also used to cover a lap for polishing rock and mineral specimens for microscopic examination. � @H� �J� }�� � � � DICTIONARY TERMS:Bolton's reagent An etching reagent for cast iron t An etching reagent for cast iron that contains picric acid, nitric acid, and water.


A monoclinic mineral, HK(UO (sub 2) )SiO (sub 4) .1-1/2H (sub 2) O ; analogous to sklodowskite, having potassium in place of magnesium; radioactive; yellow.

bolus alba

See: kaolin.


a. A more or less rounded mass of lava from a few inches to several feet in diameter, generally vesicular, at least inside, thrown from the throat of a volcano during an explosive eruption.

b. An ellipsoidal, discoidal, or irregularly rounded mass of lava ejected at a high temperature during a volcanic eruption. Bombs range upwards in size from the largest lapilli. They are characterized by a well-defined crust and are often cellular or even hollow internally. c. A missile containing an explosive, as dynamite. d. A heavy-walled reaction vessel or autoclave. Used to carry out reactions at high pressure and high temperature.

bomb calorimeter

A strong steel vessel used for determining the heat produced during combustion; used, for example, for determining the calorific value of a fuel.


a. A rich body of ore or a rich part of a deposit; a mine is in bonanza when it is operating profitably. Also, discontinuous locally rich ore deposits, esp. epithermal ones. Etymol: Sp., prosperity, success.

b. In miners' phrase, good luck, or a body of rich ore. c. Part of a precious mineral deposit that is esp. rich.


A monoclinic mineral, CuSO (sub 4) .3H (sub 2) O ; blue; partly dehydrated from chalcanthite.

bond and lease

An agreement between a mine owner and tributor that gives the latter the option of buying the mine before the lease expires.

Bond and Wang theory

A theory of crushing and grinding; the energy (h) required for crushing varies inversely as the modulus of elasticity (E) and specific gravity (S), and directly as the square of the compressive strength (C) and as the approximate reduction ration (n). The energy in horsepower hours required to crush a short ton of material is given by the following equation, in which all quantities are in feet per second units: h = [0.001748C (super 2) / SE] [(n + 2) (n - 1) / n]. The theory is due to F. C. Bond and J. T. Wang.

Bondaroy's yellow

An antimony yellow developed by Fourgeroux de Bondaroy in 1766: 12 parts white lead; 3 parts potassium antimonate; 1 part alum; 1 part sal ammoniac.

bond clay

A clay that, because of its plasticity, serves to bond relatively nonplastic materials in the fabrication of ceramic or other molded products (green bond). Also, a clay that, on firing to furnace or vitrification temperature, bonds adjacent ceramic materials that vitrify at a still higher temperature (fired bond).

bonded refractories

Refractories in which the constituents are held together by a suitable bonding material, as distinguished from fused refractories.


a. A brick that is half as wide again as a standard square (rectangular or arch); such bricks are sometimes used to begin or end a course of bonded brickwork.

b. In mining, one who welds copper connections in place between the joints of track rails, used for trolley locomotives, to complete the electrical circuit between the sections of rails. Syn: bondman.


See: bonder.

Bond's third theory

In crushing, the total work useful in breakage that has been applied to a stated weight of homogeneous broken material is invariably proportioned to the square root of the diameter of the product particles. Syn: work index.


a. A hard coallike substance high in noncombustible mineral matter; often found above or below, or in partings between, layers of relatively pure coal.

b. In the anthracite-coal trade, a carbonaceous shale containing approx. 40% to 60% of noncombustible materials. Syn: bone coal; bony coal. c. A tough, fine-grained, gray, white, or reddish quartz. d. A layer of hard, impure coal which sometimes grades uniformly into the adjacent softer coal and sometimes is sharply separated from it. Bone is usually a mixture of clay shale particles with the coal, the clay particles being well distributed.

bone ash

The white porous residue containing chiefly tribasic calcium phosphate from bones calcined in air and used esp. in making cupels, pottery, and glass and in cleaning jewelry; also, synthetic tribasic calcium phosphate used similarly.

bone bed

Applied to strata or layers that contain innumerable fragments of fossil bones, scales, teeth, coprolites, and other organic remains.

bone coal

a. Coal with a high ash content, almost rock. See also: bone. Syn: true middlings.

b. Coal that has a high ash content. It is hard and compact. Syn: bony coal. c. Argillaceous partings in coal, sometimes called slate.

bone phosphate

The calcium phosphate of bones and of phosphatic rocks, such as found in North Carolina; so called in commerce. See also: phosphorite.

bone phosphate of lime

Tricalcium phosphate, Ca (sub 3) (PO (sub 4) ) (sub 2) . The phosphate content of phosphorite may be expressed as percentage of bone phosphate of lime. Abbrev: BPL.

bone turquoise

See: odontolite.


a. A covering over a mine cage, which serves as a roof to shield it from objects falling down the shaft, thereby protecting the riders. Syn: cage cover.

b. A cap piece for an upright timber. c. The metal casing of a miner's flame safety lamp, with openings at the top and a hook for carrying the lamp. The bonnet protects the inner gauze from damage and from the impact of high-velocity air. See also: safety lamp. d. Syn: air dome. e. The cap over the end of a pipe.


Coal containing slaty material in its composition.

bony coal

See: bone.


Undressed or untreated lead ore.


Som. A box holding 6 to 8 hundredweight of coal in which waste rock is sent to the surface.

book clay

Clay deposited in thin, leaflike laminae. Syn: leaf clay.

booked mica

Lumps of mica in which laminae have not been separated into thin sheets.

book mica

Crystals of crude mica obtained from a mine in various shapes and sizes. Also called book. Syn: mine-run mica.

book structure

The alternation of ore with gangue, usually quartz, in parallel sheets. CF: ribbon.


a. A spar or beam projecting out over the drill floor from the tripod or derrick, by means of which heavy drill tools and equipment may be moved and safely handled.

b. A long, adjustable steel arm on a drill jumbo on which drifter or other types of pneumatic drills are mounted. c. A cantilevered or overhanging member or structure that supports or contains the component parts of a conveyor. It may be fixed, hinged, or pivoted. d. A pipe fixed across the last supports in a tunnel face to anchor the tail sheave of a scraper loader installation. e. In a revolving shovel, a beam hinged to the deck front, supported by cables. f. Any beam attached to lifting or excavating equipment. See also: dragline. g. Any heavy beam that is hinged at one end and carries a weight-lifting device at the other.

boom cat

See: stripping-shovel operator.

boom conveyor

Any type of conveyor mounted on a boom.

boom ditch

a. The ditch from the dam used in booming.

b. A slight channel cut down a declivity into which is let a sudden head of water to cut to the bedrock and prospect from the apex of any underlying lode.


a. In placer mining, an automatic gate in a dam that holds the water until the reservoir is filled, then opens automatically and allows the escape of such a volume of water that the soil and upper gravel of the placer are washed away. When the reservoir is emptied the gate closes and the operation is repeated. On a smaller scale it may be used to furnish water periodically for sluicing. Syn: automatic dam; flop gate.

b. A sonar transducer, used in the exploration of bottom substrata. c. Originally, an oilfield worker who migrated from one boom field to another; now, commonly, a member of a drill crew who works one job a short time, quits, and moves on to another locality to seek employment. Also called drifter. d. A combination ratchet and lever device used to tighten a chain or line about a loaded truck or wagon to hold the load in place.

boomerang sediment corer

This free-instrument-type device can be dropped over the side of a moving ship, where it will sink rapidly to the ocean floor, take a core of sediment, release ballast, and automatically return to the surface for retrieval.


The accumulation and sudden discharge of a quantity of water (in placer mining, where water is scarce). In California, the contrivances for collecting and discharging water are termed "self-shooters," an idea suggested by the sudden and violent manner in which the water makes its escape. In booming, snowmelt or water from small or ephemeral streams is collected behind a dam with a discharge gate. Placer ore is placed below the dam and when the water is released, the ore is washed through sluice boxes, ground sluices, etc., in one large surge. The dam discharge gate is closed to again begin collecting water for the next cycle. Syn: hushing.

boom man

In bituminous coal mining, one who manipulates the controls of a loading boom (conveyor) to regulate the height of the loading end of a boom, thus controlling the flow of coal from shaking screens or picking tables into railroad cars at the tipple. Also called boom operator; loader headman.


See: bort.


a. Eng. Lead ore that separates easily from its matrix and does not have to be buddled, Durham, Yorkshire, and Derbyshire. Hooson defines it as veinstuff and ore mixed. Syn: booze; bowse.

b. Derb. Gangue rock mixed with ore. See also: bouse.


An explosive of special character used in small quantities to improve the performance of another explosive, the latter forming the major portion of the charge.

booster conveyor

Any type of powered conveyor used to regain elevation lost in gravity roller or wheel conveyor lines. Syn: humper.

booster drive

An auxiliary drive at an intermediate point along a conveyor.

booster fan

A fan installed in an underground opening. A booster fan can be used as the main mine fan but is more commonly used to improve or augment the ventilation in a segment of the mine. Booster fans are illegal in U.S. coal mines but are used in metal mines and coal mines in other countries.

booster pump

a. A pump used to increase the pressure of fluids, such as to increase the pressure of water delivered to a drill when the source pressure is too low to be used for drilling operations.

b. A pump that operates in the discharge line of another pump, either to increase pressure or to restore pressure lost by friction in the line or by lift.

booster station

In long-distance pumping of liquids or mineral slurries, an intermediate pump station.


a. A projecting portion of a reinforced concrete beam, acting as a corbel to support the facing material, such as brick or stone; the lower end of a bucket elevator.

b. A leather or tin joint connecting the blast main with the tuyere or nozzle in a bloomery. c. A suspended enclosure in the nose of a tank protecting a portion of the surface and serving as a gathering opening. d. The bottom of a bucket elevator, which receives feed for delivery into an elevating bucket.


A monoclinic mineral, CuSO (sub 4) .7H (sub 2) O ; melanterite group; of a lighter blue than chalcanthite, from which it differs in its larger proportion of water.


The ejection of balled drill cuttings from the collar in long, tubelike masses.


a. The part of a drilled blasthole that remains when the force of the explosion does not break the rock completely to the bottom of the hole. See also: socket.

b. See: trespass.


One engaged in coal bootlegging. Applies to the worker in bootleg holes as well as the worker who cleans the coal in a small, impermanent breaker, and the trucker who conveys the coal to market. Bootleggers call themselves independent miners.


The mining and/or selling of coal produced from coal owned by others and without permission or knowledge of the owner.


See: boose.


An orthorhombic mineral, 8[Mg (sub 6) B (sub 14) O (sub 26) Cl (sub 2) ] ; isometric above 265 degrees C in hard, glassy, cubic and octahedral crystals; strongly pyroelectric; in evaporites, a source of boron.


Borate ore.


A salt or ester of boric acid; a compound containing the radical BO (super 3+) (sub 3) . CF: nitrate; carbonate.


A monoclinic mineral, 4[Na (sub 2) B (sub 4) O (sub 5) (OH) (sub 4) .8H (sub 2) O] (sub ) (sub ) ; soft; deposited by evaporation from alkaline lakes, playas, hot springs, and as surface efflorescence or crystals embedded in lacustrine mud. A source of boron. Syn: tincal. See also: octahedral borax.

borax bead

In blowpipe analysis, a drop of borax that when fused with a small quantity of a metallic oxide will show the characteristic color of the element; e.g., a blue borax bead indicates the presence of cobalt.

borax bead test

A chemical test to disclose the presence of certain metals in a sample. A clear glassy bead of borax fused in a wire loop will react chemically with the salts of certain metals and yield colors that help to identify the metal; e.g., manganese compounds produce a violet bead, cobalt produces a deep blue, etc. See also: blowpiping.


a. Newc. A passage or breast, driven up the slope of the coal from the gangway, and hence across the grain of the coal. A bord 4 yd (3.7 m) or more wide is called a wide bord, and one less than 4 yd in width is called a narrow bord. Also spelled board.

b. A side gallery parallel with the main road or drift. c. A road with solid coal sides. d. A narrow coal drivage in the pillar-and-stall method of working. e. A joint in a coal seam. See also: cleat. f. Eng. A road driven at right angles to the main cleavage planes of the coal.


A method of working coal seams. First bords are driven, leaving supporting pillars of coal between. Next, cross drives connect the bords, leaving supporting coal as rectangular pillars. Finally, the pillars are mined (extracted, won, robbed) and the roof is allowed to cave in. The bordroom is the space from which bord coal has been removed. Syn: bord-and-wall; stoop-and-room. See also: breast-and-pillar; stret; Warwickshire method.

bord-and-pillar method

A system of mining in which the distinguishing feature is the winning of less than 50% coal on the first working. It is more an extension of the development work than mining. The second working is similar in principle to top slicing. The remainder of the coal is won by a retreating system, the cover being caved after each unit has been worked. The term bord-and-pillar is not used to any great extent in American mining literature, but has a place in English literature. Various names have been applied to this method, such as checkerboard system, Brown panel system, following up the whole with the broken, Lancashire bord-and-pillar system, modified room-and-pillar working, narrow working, North Staffordshire method, rearer method of working inclined seams, rock-chute mining, room system, room system with caving, Warwickshire method of working contiguous seams, wide or square work, and pillar-and-breast.

bord-and-pillar working

N. of Eng. A system of mining in which interlacing roadways are driven at right angles into the seam, leaving small square or rectangular pillars of coal of from 30 to 50 yd (27 to 46 m) side length, which are then wholly or partly extracted by a small group. Syn: tub-and-stall; bord-and-wall. See also: room-and-pillar.


See: bord-and-pillar; bord-and-pillar working.

bord cleat

Eng. The main cleavage planes or joints in a coalbed.

bord course

Aust. A direction at right angles to the main cleat or facing; i.e., the length of a bord.

bord drivage

A coal drivage in the pillar-and-stall method of working.

border facies

The marginal portion of an igneous intrusion, which differs in texture and composition from the main body of the intrusion, possibly because of more rapid cooling or assimilation of material from the country rock.

bord gate

a. A main gate leading and at right angles to a bord face.

b. York. A heading driven generally to the rise, out of which stalls are opened and worked.


a. A heading driven parallel to the natural joints.

b. The space excavated in driving a bord. Used in connection with the ridding of the fallen stone in old bords when driving roads across them in pillar working; thus, "ridding across the old bordroom." c. Eng. The width across an old bord.

bordroom man

A repairer who cleans and erects supports in old workings in the bord-and-pillar method of coal mining.

bords and longwork

York. A system of working coal. First, the main levels are started on both sides of the shaft and carried toward the boundary. Second, the bord gates are worked in pairs to the rise and continued as far as the boundary, or to within a short distance of a range of upper levels and other bord gates. Lastly, the whole of the pillars and remaining coal are worked out downhill to within a few yards of the levels, and ultimately, all the coal between the levels is removed.


Eng. The direction of a place or a face being taken at right angles to the main cleavage planes of a seam.

bordways course

The direction at right angles to the main cleavage planes. In some mining districts it is termed "on face."


a. A tunnel, esp. while being excavated.

b. A circular hole made by boring.


a. A hole with a drill, auger, or other tools for exploring strata in search of minerals, for water supply, for blasting purposes, for proving the position of old workings and faults, and for releasing accumulations of gas or water.

b. A circular hole made by boring; esp. a deep hole of small diameter, such as an oil well or a water well. Also called well bore. See also: hole.

borehole bottom charge

Explosives loaded in the hole bottom at a weight or density in excess of the main charge in order to fragment difficult to break rock or to break an excessive toe burden.

borehole cable

Cable designed for vertical suspension in a borehole or shaft and used for power circuits in the mines. (A borehole cable in mining may also be a cable containing signal, telephone, or control circuits.)

borehole casing

A steel pipe lining used in a borehole, particularly when passing through loose, running ground. Flush-jointed casing that is smooth inside and outside may be either screwed or welded.

borehole deformation gage

A device for measuring the change in diameter of a hole.

borehole log

A record, made by the driller or geologist, of the rocks penetrated in the borehole. In the laboratory, a more detailed log is prepared giving particulars relating to lithology, paleontology, water analysis, etc. See also: electric log; well log.

borehole logging

The determination of the physical, electrical, and radioactive properties of the rocks traversed by a borehole.

borehole mining

The extraction of minerals in the liquid or gaseous state from the Earth's crust by means of boreholes and suction pumps. Boreholes are used for mining petroleum, and for the extraction of liquid solutions of salt, sulfur, etc. See also: well.

borehole pressure

The pressure that the hot gases of detonation exert on the borehole wall. It is primarily a function of the density of the explosive and the heat of explosion. Syn: gas pressure.

borehole pump

a. Any pump that can be suspended in a borehole; usually a centrifugal pump suspended in a borehole by its pipe range and driven by a shaft inside the pipe.

b. A centrifugal pump, electrically driven, and designed in the form of a vertical narrow chamber. It may be used to provide water, for dewatering purposes, or for borehole mining. See also: sinking pump. Also called submersible pump.

borehole samples

The samples of the rocks obtained during boring. The diamond and shot drill yield cores, while percussive drills yield sludge and chippings, which are examined to determine the nature of the rocks passed through. Borehole samples may also be required during site investigations. See also: exploratory drilling; soil core.

borehole sealing

The complete filling of a borehole with cement to prevent the entry of water into mine workings.

borehole spacing

The distance between boreholes drilled for exploration or sampling purposes. With bedded minerals, the holes may be positioned at the intersection points of coordinates or at the corners of equilateral triangles with sides from 30 to 200 m apart. The spacing is closer with patchy deposits. With metallic ores following belts across country, the holes are spaced along lines crossing the orebody in order to yield cross sections of the ore at definite intervals. In the case of known and semiproved coalfields, boreholes at 1/2- to 1-km intervals may suffice.

borehole survey

a. The process of determining the course of, and the target point reached by, a borehole, using one of several different azimuth and dip recording apparatuses small enough to be lowered into a borehole; also, the record of the information thereby obtained. Also called drillhole survey; directional survey.

b. The process of determining the mineralogical, structural, or physical characteristics of the formations penetrated by a borehole using geophysical logging apparatus small enough to be lowered into a borehole; also, the record of the information thereby obtained. c. See: well log. See also: surveying.

borehole surveying

Instrumental tests to determine the amount and direction of deflection of a borehole from vertical and horizontal planes. The instrument is lowered into the hole and tested at intervals of depth. The data obtained may be used to construct a scale model showing the actual course taken by the hole.

bore meal

a. Eng. Mud or fine cuttings from a borehole.

b. In rock drilling, the sludge from a borehole.


A tool such as a drill used for boring.

bore rod

Term used primarily by soil and foundation testing engineers for the equipment customarily called a drill rod by drillers and miners.


A group of special ceramic materials. Typical properties are great hardness and mechanical strength, high melting point, low electrical resistivity, and high thermal conductivity; impact resistance is low, but thermal-shock resistance is generally good.


a. The cutting or drilling of a hole for blasting, water infusion, exploration, or water or combustible gases drainage. See also: percussive boring; rotary boring.

b. The drilling of deep holes for the exploitation or exploration of oilfields. The term "drilling" is used similarly in connection with metalliferous deposits.

boring bar

a. A rod, made in various lengths, usually with a single chisel cutting edge, for hand drilling in rock. The blows are given by a sledge hammer.

b. A revolving or stationary bar carrying one or more cutters or drills for boring.

boring log

See: drill log.


Used by the soil and foundation testing profession as a syn. for boreholes and/or the materials removed from a borehole. CF: cuttings; sample.


An isometric mineral, 1[Cu (sub 5) FeS (sub 4) ] ; metallic; brownish bronze tarnishing to iridescent blue and purple; brittle; massive; in hypogene and contact metamorphic deposits and mafic rocks; a valuable source of copper. Syn: erubescite; variegated copper ore; peacock ore; horseflesh ore; poikilit; purple copper ore; variegated ore.


The element is not found free in nature, but occurs as orthoboric acid in volcanic spring waters and as borates in borax and colemanite. The most important source of boron is the mineral rasorite, also known as kernite. Symbol, B. Amorphous boron is used in pyrotechnic flares and in rockets as an igniter; the most important compound, boric acid or boracic acid, is used as an antiseptic; borax is used as a cleansing flux in welding and as a water softener. The isotope boron-10 is used in nuclear reactors; the nitride has lubricating properties similar to those of graphite; and the hydrides have been studied for use as rocket fuels.


See: ulexite.

boron carbide

Probably not a true compound, but instead a solution of varying amounts of carbon in a slightly distorted boron lattice; symbol, BC; black; hexagonal rhombohedral crystals; ranking next to diamond in hardness, 9.3 on the Mohs scale; and melting point, 2,350 degrees C. Used in powder form as an abrasive and in molded form as an abrasion resister. Syn: tetraboron carbide.


A former name for ulexite.

boron nitride

White; symbol, BN; hexagonal rhombohedral, crystals or powder; the powder has a Mohs hardness of 2; sublimes at about 3,000 degrees C; anisotropic; some properties vary according to the method of preparation and the crystal form. Used as a refractory; a high-temperature lubricant, as in glass molds; in furnace insulation; and in molten-metal pump parts.

boron phosphate

Symbol, BPO; sp gr, 2.81; vaporizes at 1,400 degrees C; related structurally to high cristobalite. It has been used as a constituent of a ceramic body that fires to a translucent porcelain at 1,000 degrees C.

boron phosphide

Symbol, BP; melting point, greater than 2,000 degrees C, but readily oxidizes, which limits its potential use.

boron silicides

See: silicon borides.

borrow material

Soil or sediment removed from a site for use in construction, such as sandy sediment dredged and pumped to restore an eroded beach, or clay taken to build a levee or dike.

borrow pit

a. The source of material taken from some location near an embankment where there is insufficient excavated material nearby on the job to form the embankment. Borrow-pit excavation is therefore a special classification, usually bid upon as a special item in contracts. It frequently involves the cost of land or a royalty for material taken from the land where the borrow pit is located; it also often requires the construction of a suitable road to the pit. This type of excavation therefore usually runs higher in cost than ordinary excavation.

b. An excavated area where borrow has been obtained.


a. Diamond material unsuitable for gems because of its shape, size, or color and because of flaws or inclusions. It also occurs in finely crystalline aggregates and is usually crushed into finer material. Syn: boart; bortz; boort; boartz; borts; bowr. See also: shot bort.

b. Inferior, coarsely crystalline diamonds, many of which contain black carbon or other minerals; used for core drilling, cutting, and polishing hard materials. c. Formerly used to mean the Brazilian carbonado or black diamond. d. Industrial diamond. e. Very hard, flawed or discolored diamonds used in drilling and glass cutting. f. S. Afr. Rounded forms of diamond with rough exterior and radiated or confused crystalline structure, but hardness equal to that of diamond. g. Originally the term was used as a name for all crystalline diamonds not usable as gems; later it was used to designate those diamonds not usable as gems or toolstones. Currently the term is applied to low-grade industrial diamonds suitable only for use in a fragmented form. h. A granular to very finely crystalline aggregate consisting of imperfectly crystallized diamonds or of fragments produced in cutting diamonds. It often occurs as spherical forms, with no distinct cleavage, and having a radial fibrous structure. i. A diamond of the lowest quality, so flawed, imperfectly crystallized, or off-color that it is suitable only for crushing into abrasive powders for industrial purposes (as for saws and drill bits); an industrial diamond. Originally, any crystalline diamond (and later, any diamond) not usable as a gem. j. A term formerly used as a syn. of carbonado. CF: ballas. Syn: magnetic bort. See also hailstone bort.

bort bit

See: diamond bit. Also called bortz bit and boart bit.


See: bort.

bort-set bit

See: diamond bit.


See: bort.


a. The section of a blast furnace extending upward from the tuyeres to the plane of maximum diameter.

b. A lining of quartz that builds up during the smelting of copper ores and thus decreases the diameter of the furnace at the tuyeres. c. A trough in which bloomery tools (or in copper smelting, hot ingots) are cooled.

bosh jacket

A water jacket used for cooling the walls of a shaft furnace.

bosh tank

A water tank that receives newly cast copper shapes for rapid cooling.


a. Arkansas. A coal mine employee not under the jurisdiction of the miner's union.

b. A proturberant and often dome-shaped mass of igneous rock congealed beneath the surface of the Earth and laid bare by erosion. c. An igneous intrusion that is less than 40 mi (super 2) (104 km (super 2) ) in surface exposure and is roughly circular in plan. CF: stock.


Scot. The holing or undercutting of a thick seam, as of limestone, the height of the undercutting being sufficient for a person to work in.

Boss process

Modification of the pan-amalgamation process; ore slurry flows continuously through a series of pans and settling tanks.


A light-colored hypabyssal rock, characterized by bostonitic texture and composed chiefly of alkali feldspar; a fine-grained trachyte with few or no mafic components. The name is derived from Boston, MA, for no clear reason. Not recommended usage.


Said of the texture of bostonite, in which microlites of rough irregular feldspar tend to form clusters of divergent laths within a trachytoid groundmass.


An early name for prehnite.


A monoclinic mineral, Cu (sub 2) Cl(OH) (sub 3) ; trimorphous with atacamite and paratacamite.

botanical anomaly

A local increase above the normal variation in the chemical composition, distribution, ecological assemblage, or morphology of plants, indicating the possible presence of an ore deposit or anthropomorphic contamination. See also: geobotanical prospecting.

botanical prospecting

Prospecting in which differences in plant growth or plant family serve as a clue to the presence of metals beneath barren rock or a covering of sand and gravel.


A monoclinic mineral, MgFe (super 3+) (SO (sub 4) ) (sub 2) (OH).7H (sub 2) O ; reniform, botryoidal, or globular; hyacinth-red to orange; in secondary sulfate deposits capping sulfide ore deposits. Syn: red iron vitriol.


A form in the shape of a bunch of grapes. Syn: clusterite. Adj: botryoidal.


Having the form of a bunch of grapes. Said of minerals, e.g., hematite with a surface of spherical shapes; also said of a crystalline aggregate in which the spherical shapes are composed of radiating crystals. CF: colloform; colloid minerals; reniform.


A radiated, columnar variety of datolite with a botryoidal surface.


a. The floor or footwall of an underground mine.

b. The landing of a shaft or slope. c. See: gutter. d. To complete a borehole. e. To construct the bottom of or for; said specif. of underdraining a level. f. To strike bedrock or clay when sinking a shaft. g. The landing at the bottom of the shaft or slope. h. The lowest point of mining operations. i. To underrun (as a gold deposit that is to be worked by the hydraulic method) with a level for drainage. j. Surface in a borehole parallel to the face of a drill bit. k. A mass of impure metal formed below the matte, in matting metal ores. l. The footwall of a metalliferous deposit. m. Barren bedrock. n. The rock formation below the alluvium on which the gold or tin wash dirt is met. o. In gemstones, the pavilion. p. Pennsylvania. The stratum, rock, or floor on which a coal seam lies. q. To break the material and throw it clear from the bottom or toe of the borehole. r. To place a drill bit in contact with the bottom of a borehole. s. Surface in a borehole parallel to the face of a drill bit. t. In metal-melting furnaces, this is usually the hearth or crucible. See also: bottoming.

bottom bed

Eng. Universally applied to the lowest bed in a quarry. Also used in Southeast England for the basal bed of the Tertiary, whether Thanet sand or Reading beds, resting on an eroded surface of the Chalk.

bottom belt conveyor

A belt conveyor that carries the coal or ore on the lower strand; often used where height is limited.

bottom benching

The method by which the bench is removed from below as with a power shovel. See also: benching.

bottom bounce

Technique by which sonar impulses are reflected off the ocean bottom one or more times before reaching the target. Also refers to diving.

bottom break

The break or crack that separates a block of stone from a quarry floor.

bottom canch

In leveling an underground roadway, a part taken out below a bed. See also: canch.

bottom coal

Coal below the undercut; it may or may not be removed.

bottom cut

a. A machine cut made in the bottom or floor of a seam before shot firing. See also: cutting horizon; middle cut; top cut.

b. A drill hole pattern. See also: drag cut. c. In drilling and blasting a tunnel, the lower of two converging lines of horizontally spaced holes. Upper line is draw cut. When blasted simultaneously, a wedge of rock is removed.

bottom cutter

A dinter; a coal cutter for making floor cuts.

bottom diameter

The diameter of a circle tangent to the seating curve at the bottom of the tooth gap of a roller chain sprocket. Equal to the pitch diameter minus the chain-roller diameter.

bottom-discharge bucket conveyor

A conveyor for carrying bulk materials in a horizontal path consisting of an endless chain to which roller-supported, cam-operated, bottom-discharge conveyor buckets are attached continuously.

bottom-discharge conveyor bucket

A vessel generally rectangular or square in plan and having a bottom consisting of an undercut gate.

bottom-dump car

See: mine car.

bottom-dump scraper

A carrying scraper that dumps or ejects its load over the cutting edge.

bottom-dump semitrailers

Suitable for transporting free-flowing materials over a reasonably level haul route that permits a high travel speed. They can be used where the maximum flotation of a large single tire is required and where dumping in windrows over a wide area is practical. See also: bottom dump truck.

bottom dump truck

A trailer or semitrailer that dumps bulk material by opening doors in the floor of the body. Also called dump wagon. See also: bottom-dump semitrailers.


a. A completed borehole, or the point at which drilling operations in a borehole are discontinued.

b. Said of shafts and slopes on being driven to completion when reaching base of coal seam.

bottom-emptying skip

A skip equipped with a bottom discharge gate.

bottom equipment

a. The tools or equipment attached to the lower end of a drill string and normally used at or near the bottom of a borehole. Also, the nondrilling equipment placed and operated at or near the bottom of a borehole, such as a pump unit or strainer.

b. Mine equipment used solely for work at the mine bottom, such as rotary dump and switch motor (if used to spot cars in rotary dump).

bottom filler

A worker who fills a barrow with ore, coke, or stone, weighs it, and then places it on the cage or elevator to be hoisted to the top of the furnace.

bottom gate

The gate road at the lower end of an inclined coal face. See also: main gate; tailgate; top gate.

bottom heading

a. Method of excavating tunnels, drifts, or other mine openings. The bottom heading, which may be either driven in successive stages or holed through, is subsequently enlarged by excavating the top section.

b. Overhand bench.

bottom hole

A point at, or near, the bottom of a borehole.

bottom-hole pressure

a. The load, expressed in pounds or tons, applied to a bit or other cutting tool while drilling.

b. The pressure, expressed in pounds per square inch, produced at the bottom of a borehole by the weight of the column of circulation or other liquid in a borehole. c. The pressure, expressed in pounds per square inch, exerted by gas or liquids ejected from the rocks at or near the bottom of a drill hole. d. Pressure measured in a well opposite the producing formation. If the well is flowing, the flowing bottom-hole pressure will be obtained; if the well is not producing and has not been producing for a sufficient time, the pressure will be the fully built-up, or static, bottom-hole pressure. CF: ground pressure.

bottom-hole temperature

The temperature of the fluid at or near the bottom of a borehole; significantly lower than the temperature of the formation if borehole fluids have been circulated recently or are being produced with expansion into the well bore.


The downward pinching-out or termination of an orebody, either structurally or by economic grade. See also: bottom.

bottom lift

a. The lowest or deepest lift or level of a mine.

b. The deepest columns of a pump. c. The deepest lift of a mining pump, or the lowest pump.

bottom loading belt

A bottom belt conveyor.

bottom maker

A laborer who relines bottoms of ingot soaking pits with coke dust to retard formation of oxide scale on hot ingots.

bottom pillar

A large block of solid coal left unworked around the shaft. See also: shaft pillar.

bottom-pour ingot assembly

One comprising hot tops, wood blocks, ingot mold, mold stool, lateral outlet bricks, lateral bricks, king brick, fountain bricks, funnel brick, and suitable metal supporting devices.

bottom-pour ladle

A ladle poured through a refractory nozzle in the bottom.

bottom rock

See: bedrock.


a. Used in connection with the Orford process for separating nickel and copper as sulfides. When the mixed sulfides are fused with sodium sulfide, the nickel sulfide separates to the bottom. See also: tile copper.

b. The material drawn off from the bottom of a tower or still. Any residue accumulating in the bottom of a process vessel.

bottom sample

A sample obtained by collecting a portion of material on the bottom of a container or pipeline.

bottom sampler

One of various types of apparatus capable of piercing the sea bottom and retaining a sample of the deposit when brought to the surface.

bottom sheets

The steel plates forming the bottom of an oil still or a steam boiler.

bottom subsidence

See: subsidence.

bott plug

A clay ball used for stopping the taphole in a cupola furnace.

bott stick

A long stick used for inserting the bott plug into the taphole to stop the flow of metal.


a. One of a series of elongate, sausage-shaped segments occurring in boudinage structure, either separate or joined by pinched connections, and having barrel-shaped cross sections.

b. A term applied loosely, without regard to shape or origin, to any tectonic inclusion. Etymol: French, bag; blood sausage.


A structure common in strongly deformed sedimentary and metamorphic rocks, in which an original continuous competent layer or bed between less competent layers has been stretched, thinned, and broken at regular intervals into bodies resembling boudins or sausages, elongated parallel to the fold axes. See also: pull-apart structure.

Bouguer anomaly

A gravity anomaly calculated after corrections for latitude, elevation, and terrain. Pron: boo-gay. See also: anomaly; Bouguer correction.

Bouguer correction

A correction made to gravity data for the attraction of the rock between the station and the datum elevation (commonly sea level); or, if the station is below the datum elevation, for the rock missing between station and datum. The Bouguer correction is 0.01276 ph mgal/ft, or 0.04185 ph mgal/m, where p is the specific gravity of the intervening rock and h is the difference in elevation between station and datum. See also: Bouguer anomaly.

Bouguer gravity

Gravity values after latitude, elevation, and Bouguer corrections have been applied. Used in the gravitational method of geophysical prospecting.

Bouguer reduction

The correction made in a gravity survey to take account of the altitude of the station and the rock between the station and sea level.


A monoclinic mineral, Pb (sub 5) Sb (sub 4) S (sub 11) ; metallic; bluish-gray; massive.


a. A detached rock mass larger than a cobble, having a diameter greater than 10 in (25.4 cm) or 8 phi units, or about the size of a volleyball, being somewhat rounded or otherwise distinctively shaped by abrasion in the course of transport; the largest rock fragment recognized by sedimentologists. In Great Britain, the limiting size of 8 in (20.3 cm) has been used.

b. See: boulder stone. c. A general term for any rock that is too heavy to be lifted readily by hand. Also spelled bowlder.

boulder blasting

a. The breaking down of large stones at quarries by small explosive charges. See also: secondary blasting.

b. Secondary blasting of rocks too big to be moved conveniently in the mine's transport system.

boulder buster

An explosive used to break rock fragments by blockholing or mudcapping methods.

boulder clay

a. The stiff, hard, and usually unstratified clay of the drift or glacial period that contains boulders scattered through it. Also called till; hardpan; drift clay; drift. See also: till; moraine.

b. Glacial drift that has not been subjected to the sorting action of water and therefore contains mixed particles ranging from boulders to clay sizes.

boulder flat

A level tract covered with boulders.

boulder gravel

An unconsolidated deposit consisting mainly of boulders.

boulder motion

A surface quarry worked only in detached masses of rock overlying the solid rock; sometimes contracted to motion.

boulder quarry

A quarry in which the joints are numerous and irregular, so that the stone has been broken naturally into comparatively small blocks. A local term applied to certain marble quarries in the region of Knoxville, TN, where erosion has formed many large cavities and cracks, between which the rock stands up as pinnacles. The cavities are now filled with clay.

boulder stone

An obsolete term for any large rock mass lying on the surface of the ground or embedded in the soil, differing from the country rock of the region, such as an erratic. Syn: boulder.


A fused mass of synthetic material up to 5 cm long, pear or carrot-shaped, particularly as produced by the Verneuil or Crochralshi processes in the production of synthetic sapphire, ruby, spinel, or rutile. Etymol: Fr. "ball." Syn: birne. See also: Verneuil process.


A small ovoid; an egg-shaped briquette.


a. A sudden spalling off of the sides of ribs and pillars due to excessive pressure; a bump.

b. The rapid up-and-down reciprocating motion induced in a drill string by rod vibration, drill string wrap-up, excessive volume or pressure of circulation media, or the running of a bit on and over small, loose materials on the bottom of a drill hole.

bounce cast

Casts of short grooves (up to 5 cm) widest and deepest in middle and fading out at both ends; presumably formed by objects grazing against bottom and rebounding. See also: impact cast. CF: prod mark.


Corn. An area taken up for tin mining; a tin bound.


a. A line between areas of the Earth's surface occupied by rocks or formations of different type and age; esp. used in connection with geologic mapping; also, a line between two formations or cartographic units on a geologic map.

b. The limit, border, or termination of a coal or mineral take; a line along which workings must stop in the vicinity of a fault or old waterlogged workings. Also called march.

boundary fault

A major fault with a considerable displacement. A number of collieries and coalfields are limited along one side by such a fault.

boundary films

Films of one constituent of an alloy surrounding the crystals of another constituent.

boundary map

A map created for the purpose of delineating a boundary line and the adjacent territory.

boundary pillar

A pillar left in mines between adjoining properties.

bound gravel

A hard, lenticular, cemented mass of sand and gravel occurring in the region of the water table; it is often mistaken for bedrock.

Bourdon tube

Pressure gage, made from elliptical curved tube, which straightens somewhat under pressure, and is made to move a measuring needle over a dial.


An orthorhombic mineral, 4[PbCuSbS (sub 3) ] ; shows wheel-shaped twin crystals; a source of lead, copper, and antimony. Syn: wheel ore; cogwheel ore; endellinite; endellionite; berthonite.


N. of Eng. Ore mixed with veinstone; second-class ore that must undergo further preparation before going to the smelter. See also: boose.

bouse team

N. of Eng. The place where bouse is deposited outside a mine, ready to be dressed or prepared for the smelter.


Derb. A method of measuring lead ore.


A peculiar green and very pure glass, found as rolled pebbles. Also called bottle stone; pseudochrysolite--the latter from its resemblance to olivine. It is not solely a rock, as it may be prehistoric slag or glass. See also: moldavite.


a. Scot. A road by which the miners can reach the surface.

b. A passage around a shaft at a landing. c. A traveling road from one seam to another.


a. Scot. A mass of roof consisting of stone or shale.

b. Scot. A projecting stone in a shaft or underground road.


a. A hard, compact, greenish-white to yellowish-green serpentine once thought to be nephrite jade; translucent; massive, fine-grained; consists of a dense feltlike aggregate of colorless antigorite fibers with patches of magnesite, flakes of talc, and grains of chromite. Syn: bowenite jade.

b. N.Z. Serpentine rock (serpentinite). Syn: tangiwai; tangiwaite; tangawaite.

bowenite jade

See: bowenite.

Bowen's reaction series

See: reaction series.


a. S. Staff. A small wooden box in which iron ore is hauled underground. Syn: hudge.

b. Aust. An iron bucket used for raising rock, etc., while sinking. Syn: hudge. c. A noise made by the cracking of the strata owing to the extraction of the coal beneath. d. Bucket; kibble; hoppit, as used in sinking. e. A large iron barrel used for men's tools and debris when sinking a shaft. f. The noise made by the escape of gas under pressure.


a. The bucket or body of a carrying scraper.

b. The moldboard or blade of a dozer. c. Stationary part of a Symons crusher, which surrounds the cone (the grating member). d. See: spider.

bowl classifier

A hydraulic classifier similar to a thickener, but differs in that the current carries the fine material into the overflow; used to make separations at very fine particle size.


See: boulder.


See: saponite.

bowl scraper

A steel bowl hung within a fabricated steel frame, running on four or two wheels. Its bottom edge digs into the ground, the bowl being filled as it is drawn forward by a tractor; soil is ejected at the dump by a tailgate, moved by wire ropes or hydraulically. Towed scrapers transport soil, in addition to spreading and leveling it. See also: wheel scraper.


See: bort.


See: boose.


a. A unit in a sluice for washing gravel; a sluicebox. Syn: box condenser.

b. A dump body. c. To place core samples in a lidded, traylike, partitioned container for safekeeping after they have been removed from the core barrel; also, the container in which core samples are placed after they have been removed from a core barrel. Also called corebox; core tray. d. To drill boreholes at the four corners of a square area at equal distances from a centrally located and already completed borehole.

box barrow

A large wheelbarrow with upright sides.

box bell

See: bell screw.

box canyon

a. A narrow gorge or canyon containing a stream following a zigzag course, characterized by high, steep rock walls and typically closed upstream with a similar wall, giving the impression as viewed from its bottom of being surrounded or boxed in by almost-vertical walls.

b. A steep-walled canyon heading against a cliff; a dead-end canyon. Syn: cajon.

boxcar loader

a. Any of several types of conveyors adapted by portable or hinged mounting for use in loading bulk materials into boxcars. Some types operate at high speeds and throw the materials to the ends of the car. See also: idler disk.

b. In anthracite and bituminous coal mining, one who loads coal into railroad boxcars by mechanical shovel or conveyor loader. Syn: thrower belt; car loader; loader engineer; loader runner. See also: portable conveyor.

box check

A ventilation control consisting of a stopping or a curtain with a hole, through which a conveyor can pass. The box check serves as a ventilation regulator in a belt haulage entry. See also: boxes; conveyor airlock.

box condenser

See: box.

box cut

The initial cut driven in a property, where no open side exists; this results in a highwall on both sides of the cut.

box-cut method

A method of opencast mining of coal where the dip of the seam is relatively steep. A boxlike excavation is made to the dip, or at an angle to it, and the coal seam is worked to the right and left. See also: strike working.

box-cut spoil

That spoil created from the initial excavation of a pit or pits which is placed upon the surface of adjacent lands. The term does not include spoil from subsequent excavations, which is placed in previously excavated pits.


a. Pennsylvania. Wooden partitions for conducting the ventilation from place to place. See also: box check.

b. More or less hollow cuboidal limonitic concretions. c. Eng. Pebbles of hard brown sandstone at the base of the Red and Coralline Crags in East Anglia, containing remains of a fossil; so called by the Suffolk phosphate diggers.

box filling

The use of metal trays, instead of shovels, for hand-filling coal into trams. The collier scooped the lumpy coal into the box and discarded the small material, which had little market value. The use of a box was compulsory at many collieries until several decades ago. See also: fork-filled; loading pan.

box groove

A closed groove between two rolls, formed by a collar on one roll and fitting between collars on another.

box heading

A heading driven through very loose ground with close timbering.


A method of securing shafts solely by slabs and wooden pegs.

box loader

In the quarry industry, one who loads broken rock into a large box, placed on a small truck running on a narrow gauge track, to be hoisted out of the quarry pit. Syn: grouter; rock loader.

box scraper

See: scraper.

box sluice

An open wooden channel or flume for conveying placer sand. The gold or heavy minerals settle at the bottom. The method is cleaner and requires less water than ground sluicing.

box tap

See: bell tap.

box timbering

Use of rectangular close frame for lining shafts or drives. See also: plank timbering.


A network of intersecting blades or plates of limonite or other iron oxide, deposited in cavities and along fracture planes from which sulfides have been dissolved by processes associated with the oxidation and leaching of sulfide ores, esp. porphyry copper deposits.


Local name for probertite.


Staff. A bluish iron ore. See also: boilum.

Boylston's reagent

A 5% solution of nitric acid in absolute ethyl or methyl alcohol, used for the general etching of normal carbon steels. Syn: nital.


Bone phosphate of lime.


Letter name specifying the dimensions of bits, core barrels, and drill rods in the B-size and Q-group wireline diamond drilling system having a core diameter of 36.5 mm and a hole diameter of 60 mm.