Appendix:Dictionary of Mining, Mineral, and Related Terms/B/1

baaken
 * S. Afr. A boundary mark.

Babcock and Wilcox mill
 * Dry-grinding mill in which steel balls rotate in a horizontal ring, through which the feed is worked downward.

Babel quartz
 * A variety of quartz, named for the fancied resemblance of the crystal to the successive tiers of the Tower of Babel. Syn: Babylonian quartz.

Babylonian quartz
 * See: Babel quartz.

bacalite
 * a. A variety of amber.

b. A variety of quartz in Baja California, Mex.

back
 * a. A system of joints in coal oblique to the bedding, at an angle of about 35 degrees to 75 degrees . Backs are usually perfectly tight and have polished cheeks which suggest a certain amount of movement. Back may be applied to the principal cleat. See also: backs; cleat.

b. The roof or upper part of any underground mining cavity. c. The ore between a level and the surface, or between two levels. See also: back of ore. d. That part of a lode which is nearest the surface relative to any working part of a mine, thus the back of the level or stope is that part of the unstoped lode which is above. See also: back of lode. e. A joint, usually a strike joint, which is perpendicular to the direction of working. f. As applied to an arch, the outer or upper surface. g. The pavilion of a gemstone.

back acter
 * Front-end equipment fitted to an excavator, comprising a jib with an arm and bucket. Although designed primarily for vertically sided trenching, it is also useful for bulk excavation below track level.

back and underhand stoping milling system
 * See: combined overhand and underhand stoping.

back arch
 * A concealed arch carrying the backing or inner part of a wall where the exterior facing material is carried by a lintel.

back balance
 * a. A type of self-acting incline in a mine. A balance car is attached to one end of a rope, and a carriage for the mine car is attached to the other end. A loaded car is run on the carriage and is lowered to the foot of the incline, raising the balance car. The balance car in its descent raises the carriage when the carriage is loaded only with an empty car.

b. The means of maintaining tension on a rope transmission or haulage system, consisting of the tension carriage, attached weight, and supporting structure.

backblast
 * See: backlash.

back break
 * Rock broken beyond the limits of the last row of holes marking the outer boundary in a blast.

back brusher
 * a. A ripper engaged in taking down the roof in roadways some distance back from the face. Syn: second ripping.

b. Back ripper.

back-bye work
 * General work performed behind the working faces, as opposed to work done at the faces. This is commonly referred to as "outby work."

back casing
 * Eng. A temporary shaft lining of bricks laid dry, and supported at intervals upon curbs. When the stonehead has been reached, the permanent masonry lining is built upon it inside of the back casing.

backcast stripping
 * A stripping method using two draglines, one of which strips and casts the overburden while the other recasts a portion of the overburden.

back coal
 * Scot. Coal that miners are allowed to carry home.

back coming
 * Scot. Working away the pillars that are left when mining coal inby. Robbing pillars; back working. See also: back work.

back-end man
 * A worker who works behind the coal-cutter as it moves along the face. Duties may include cleaning the cuttings from behind the machine and setting props to support the roof or overhang of coal. CF: coal-cutter team.

back entry
 * The air course parallel to and below an entry or the entry used for secondary purposes in two-entry system of mining. Locally, any entry not having track in it.

backfill
 * a. Waste sand or rock used to support the roof or walls after removal of ore from a stope.

b. Sand or dirt placed behind timber, steel, or concrete linings in shafts or tunnels. c. The process of sealing and filling, and/or the material used to seal or fill, a borehole when completed, to prevent its acting as a course along which water may seep or flow into rock formations or mine workings. d. Material excavated from a site and reused for filling, for example, the use of stones or coarse gravel for filling draining trenches. See also: fill.

back filling
 * a. Rough masonry built in behind the facing or between two faces; similar material used in filling over the extrados of an arch; also, brickwork used to fill in space between studs in a frame building, sometimes called brick nogging.

b. The filling in again of a place from which the rock or ore has been removed.

back-filling system
 * Filling lower or older workings with the waste from newer workings. See also: overhand stoping; square-set stoping.

backfire
 * a. A fire started to burn against and cut off a spreading fire.

b. An explosion in the intake or exhaust passages of an engine.

backfolding
 * Folding in which the folds are overturned toward the interior of an orogenic belt. In the Alps, the backward folds are overturned toward the south, whereas most of the folds are overturned toward the north. Syn: backward folding.

background
 * a. The abundance of an element, or any chemical property of a naturally occurring material, in an area in which the concentration is not anomalous.

b. The slight radioactivity shown by a counter, due to normal radioactivity from cosmic rays, impurities in the counter, and trace amounts of radioactivity in the vicinity.

backhand
 * In bituminous coal mining, one who assists either the machineman or machine loader to move and set up a coal cutting or loading machine at the working face.

backhaul
 * A line that pulls a drag scraper bucket backward from the dump point to the digging.

backhaul cable
 * In a cable excavator, the line that pulls the bucket from the dumping point back to the digging.

back heading
 * a. Eng. The companion place to a main winning.

b. See: back entry.

backhoe
 * The most versatile rig used for trenching. The basic action involves extending its bucket forward with its teeth-armed lip pointing downward and then pulling it back toward the source of power.

back holes
 * In shaft sinking, raising, or drifting, the holes that are shot last.

backing
 * a. Timbers fixed across the top of a level supported in notches cut in the rock.

b. The action of a roof layer of combustible gases flowing uphill against the direction of the ventilation.

backing deals
 * Boards from 1 to 4 in (2.5 to 10 cm) thick and of sufficient length to bridge the space between timber or steel sets or between rings in skeleton tubing. Usually, planks 9 to 12 in (23 to 30 cm) in width are used. Round poles, either whole or split, light steel rails, ribbed sheet metal, and reinforced concrete slabs are sometimes used in place of planks. Backing deals tighten the supports against the ground and also prevent the collapse of material between the timber or steel sets or rings. See also: lagging.

backing off
 * A term used to describe the operation of removing excessive body metal from badly worn bits.

backing sand
 * Reconditioned sand used for supporting the facing sand, and forming the main part of a foundry mold.

backjoint
 * a. A joint plane more or less parallel to the strike of the cleavage, and frequently vertical.

b. A rabbet or chase left to receive a permanent slab or other filling.

backlash
 * a. The return or counterblast, as the recoil or backward suction of the air current, produced after a mine explosion. Also called backblast; suction blast.

b. The reentry of air into a fan. c. The violent recoil and whipping movement of the free ends of a rope or wire cable broken under strain. d. Lost motion, play, or movement in moving parts such that the driving element (as a gear) can be reversed for some angle or distance before working contact is again made with the secondary element.

back leads
 * Applied to black sand leads on coastlines which are above high-water mark.

back mine
 * Scot. A passage in a mine crosscut toward the dip of the strata.

back-off shooting
 * The firing of small explosive charges for releasing stuck drilling tools in a borehole. The shock of detonation causes the joint to expand and unscrew slightly. All rods above the joint can then be removed from the hole.

back of lode
 * The portion of a lode lying between a level driven in a lode and the surface. See also: back.

back of ore
 * The ore between two levels which has to be worked from the lower level. See also: back.

back-out switch
 * See: hoist back-out switch.

back pressure
 * a. Resistance transferred from rock into drill stem when bit is being fed at a faster rate than the bit can cut.

b. Pressure applied to the underside of the piston in the hydraulic-feed cylinder to partially support the weight of the drill rods and hence reduce pressure on the bit. c. Rock pressures affecting the uppermost portion or roof in an underground mine opening.

back prop
 * The name given to the raking strut that transfers the load from the timbering of a deep trench to the ground. These struts are provided under every second or third frame according to the type of ground being excavated.

back ripper
 * See: back brusher.

back rippings
 * The taking down of a thickness of roof beds in roadways some distance back from the face. The thickness of roof excavated may vary from 1 ft (0.3 m) or so to 6 ft (1.8 m) and more. This work is necessary where there has been a gradual reduction in height, as a result of roof sag, and opening height must be maintained. See also: second ripping.

backrush
 * The seaward return of the water following the uprush of waves. For any given tide stage, the point of farthest return seaward of the backrush is known as the limit of backrush or limit of backwash. See also: backwash.

backs
 * a. The height of ore available above a given working level. If the orebody has been proved by shaft sinking to a depth of 300 ft (91 m) from the surface, the orebody is said to have 300 ft (91 m) of backs. See also: back.

b. A quarryman's term for one set of joints traversing the rock, the other set being known as cutters. c. A system of joints in coal or stratified mineral oblique to the bedding at an angle of 35 degrees to 75 degrees. See also: slips. d. Slips; used to denote a slip met with first at floor level. Syn: hugger.

backs and cutters
 * Jointed rock structures, the backs (joints) of which run in lines parallel to the strike of the strata, the cutters (cross joints) crossing them at about right angles.

backscatter
 * The emergence of radiation from that surface of a material through which it entered. Also used to denote the actual backscattered radiation.

backshift
 * a. The afternoon or night shift; any shift that does not fill coal or is not the main coal-production shift.

b. N. of Eng. The second or middle shift of the day; varies from 9 to 10:30 a.m. until 4:30 to 6 p.m. in different pits.

back shot
 * A shot used for widening an entry; it is placed at some distance from the head of an entry.

backsight
 * a. A sight or bearing on a previously established survey point (other than a closing or check point), taken in a backward direction.

b. A reading taken on a level rod held in its unchanged position on a survey point of previously determined elevation when the leveling instrument has been moved to a new position. It is used to determine the height of the instrument prior to making a foresight. Syn: plus sight. Abbrev: BS. Ant: foresight.

backsight hub
 * A mark or stake placed at some distance behind the position a drill will occupy in a specific compass direction from the borehole marker for an incline hole to enable the driller to set the drill and drill the borehole in the intended direction. Also called back hub; backsight. See also: picket.

back skin
 * Newc. A leather covering worn by workers in wet workings.

back slip
 * A joint in a coal seam that is inclined away from the observer from floor to roof. It would be a face slip from the opposite direction. CF: face slip.

back slope
 * a. S. Wales. A slope with the stalls branching off and working the seam with back slips along the face.

b. In geology, the less sloping side of a ridge. Contrasted with escarpment, or steeper slope; esp., the slope more nearly parallel with the strata. Also called structural plain. c. The term is used where the angle of dip of the underlying rocks is somewhat divergent from the angle of the land surface. The slope at the back of a scarp; e.g., the gentler slope of a cuesta or of a fault block. It may be unrelated to the dip of the underlying rocks. Also spelled: backslope. d. Syn: dip slope.

back splinting
 * The working of the top portion of a thick seam that was left as a roof when the bottom portion was worked. The top coal is recovered by working over the goaf or packs of the first working. See also: back work.

backstamp
 * The maker's name and/or trademark stamped on the back of pottery flatware or under the foot of hollowware.

backstay
 * A drag or trailer fixed at the back of a haulage train (or set) as a safety device when going uphill. See also: drag. CF: bull.

backstone
 * Eng. Shaly mudstone used for cooking slabs, quarried near Delph, Yorkshire. Also, a bed in the Staffordshire Coal Measures.

back stope
 * To mine a stope from working below.

back stopes
 * Overhead stopes; stopes worked by putting in overhead holes and blasting down the ore.

backstroke jigging
 * A process in which strong suction is advocated at all times with the dense-medium process, since none of the bone medium must be allowed to get over into the washed coal.

backup gear
 * See: reverse-feed gear.

back vent
 * Scot. An air course alongside the pillar in wide rooms.

backwardation
 * The situation when the cash or spot price of a metal is greater than its forward price. A backwardation occurs when a tight nearby situation exists in a metal. The size of the backwardation is determined by differences between supply and demand factors on the nearby positions compared with the same factors on the forward position. There is no official limit to the backwardation. The backwardation is also referred to as the "back."

backward folding
 * See: backfolding.

backwash
 * a. In uranium leaching, flushing from below of colloidal slime from ion exchange column after adsorption cycle. The cleaning of sand filters.

b. Water or waves thrown back by an obstruction such as a ship, breakwater, cliff, etc. c. The return flow of water seaward on a beach after the advance of a wave. See also: backrush.

back work
 * a. Any kind of operation in a mine not immediately concerned with production or transport; literally work behind the face; repairs to roads.

b. See: back coming; back splinting.

bacon
 * Eng. Fibrous carbonate of lime, also known as beef and horseflesh; Isle of Portland. See also: beef.

bacon stone
 * a. Eng. Calcspar colored with iron oxide, Bristol.

b. An old name for a variety of steatite (rock gypsum), alluding to its greasy luster. See also: speckstone.

baculite
 * A crystallite that appears as a dark rod.

bad air
 * Air vitiated by powder fumes, noxious gases, or respirable dust.

baddeleyite
 * A monoclinic mineral, ZrO (sub 2) ; may contain some hafnium, titanium, iron, and thorium.

badlands
 * A region nearly devoid of vegetation where erosion has produced, usually in unconsolidated or poorly cemented clays and silts, a dense and intricate drainage pattern with short steep slopes and sharp crests and pinnacles. Specif., the Badlands of the Dakotas.

bad top
 * A coal mining term indicating a weak roof. Bad top sometimes develops following a blast.

baeumlerite
 * A colorless chloride of potassium and calcium, KCl.CaCl (sub 2) . Intergrown with halite and tachyhydrite. Orthorhombic. Syn: chlorocalcite. From Leintal, Germany.

baff ends
 * Long wooden edges for adjusting linings in sinking shafts during the operation of fixing the lining.

baffle board
 * A board fitted across a compartment in an ore washer to retain the heavy ore and allow the light material to flow away.

baffle plate
 * a. A loading plate attached to the frame of a belt conveyor to prevent spillage at any loading point.

b. A tray or partition placed in a tower, a heat exchanger, or other processing equipment to direct or to change the direction of flow of fluids. c. A metal plate used to direct the flames and gas of a furnace to different areas so that all portions of it will be heated; a deflector.

baffler
 * A partition in a furnace so placed as to aid the convection of heat; a baffle plate.

baffle tube
 * A pipe of sufficient length to lower the temperature of hot gases before the gases enter a furnace.

baffle wall
 * A refractory wall used to deflect gases or flames from the ware and to provide better heat distribution in the furnace structure.

bag
 * a. A paper container roughly 2.5 to 5 cm in diameter and 20 to 46 cm long, used for placing an inert material, such as sand, clay, etc., into a borehole for stemming or tamping. Also called a tamping bag.

b. A long tube fastened at the upper end to a pipe leading from a smelter, and gathered and tied at the lower end. The smoke passes through the cloth, which catches the solids. The bag is periodically untied and the dust is shaken out. See also: baghouse. c. A cavity in coal containing gas or water. See also: bag of gas. d. Flexible pipe or hose. Also called bagging. e. S. Staff. A quantity of combustible gases suddenly given off by the coal seam. See also: bag of foulness. f. York. A miner's term for a variety of inferior coal.

bag filter
 * An apparatus for removing dust from dust-laden air, employing cylinders of closely woven material that permit passage of air but retain solid particles. Syn: filter.

baghouse
 * Chamber in which exit gases from roasting, smelting, melting, or calcining are filtered through membranes (bags) that arrest solids such as fine particulates. See also: bag.

bag of foulness
 * N. of Eng. A cavity in a coal seam filled with combustible gases under a high pressure, which, when cut into, are given off with much force. See also: bag.

bag of gas
 * Eng. A gas-filled cavity found in seams of coal. See also: bag.

bag powder
 * Originally applied to black powder loaded in bags, but now applied to a number of explosives so packed. The bags are long, cylindrical units about 6 in (15 cm) in diameter and weighing 12-1/2 lb (5.67 kg) apiece.

bag process
 * A method of recovering flue dust and also sublimed lead, whereby furnace gases and fumes are passed through bags suspended in a baghouse. The furnace gases thus are filtered, and the particles in suspension collected.

bahada
 * See: bajada.

baikalite
 * A dark-green variety of diopside containing iron; found near Lake Baikal, Russia.

baikerinite
 * A thick, tarry hydrocarbon that makes up about one-third of baikerite and from which it may be separated by alcohol. See also: baikerite.

baikerite
 * a. A waxlike mineral from the vicinity of Lake Baikal, Russia, apparently about 60% ozocerite.

b. A variety of ozocerite. See also: baikerinite.

bail
 * a. As used by churn drillers, to remove a liquid from a borehole by use of a tubular container attached to a wire line. See also: bailer.

b. The handle on a bucket, cage, or skip by means of which it may be lifted or lowered. c. A large clevis. d. To dewater a mine with a skip or bailer. e. As used by the diamond- and rotary-drilling industries, (1) a U-shaped steel rod with the open ends formed into eyes fitting over two lugs projecting from the sides of a water swivel, or (2) a U-shaped steel rod with open ends attached to an open-sided, latch-equipped, circular collar, that fits around a drill rod and under the base of a water swivel. Both types of bails are designed to permit circulation of fluid through the drill rod string while the rods are suspended on the hoist line or while the rods are being raised or lowered a few feet with the hoisting cable.

bailer
 * a. A long cylindrical vessel fitted with a bail at the upper end and a flap or tongue valve at the lower extremity. It is used to remove water, sand, and mud-laden or cuttings-laden fluids from a borehole. When fitted with a plunger to which the bailing line is attached, it sucks the liquid in as it is lifted and is then called a sand pump or an American pump. Syn: bucket.

b. A metal tank, or skip, with a valve in the bottom, used for dewatering a mine. c. See: sludger; swab. d. In bituminous coal mining, a laborer who scoops water from drainage ditches in a mine with a bucket and empties it into a water car, a ditch flowing to a natural outlet or to a pumping station. Also called water bailer. e. A cylindrical steel container with a valve at the bottom for admission of fluid, attached to a wire line and used in cable-tool drilling for recovering and removing water, cuttings, and mud from the bottom of a well. See also: bail; bailing.

bailiff
 * Eng. A name formerly used for manager of a mine.

bailing
 * a. Removal of the cuttings from a well during cable-tool drilling or of liquid from a well by means of a bailer.

b. Dewatering a mine. See also: bailer. c. Removing rock dust and other material loosened in the drilling by means of a bucket or ball.

bajada
 * a. A broad, continuous alluvial slope or gently inclined detrital surface extending from the base of mountain ranges out into and around an inland basin, formed by the lateral coalescence of a series of alluvial fans, and having an undulating character due to the convexities of the component fans; it occurs most commonly in semiarid and desert regions, as in the Southwestern United States. A bajada is a surface of deposition, as constrasted with a pediment (a surface of erosion that resembles a bajada in surface form), and its top often merges with a pediment. Etymol: Sp., descent, slope. CF: alluvial slope; alluvial fan. Syn: bahada; alluvial plain; piedmont plain.

b. See: ladderway. c. Sp. Compound alluvial fans.

baja de metales
 * Peru. Lowering of ores from mine to mill.

bajo
 * Colom. Low-lying alluvial mines that have to be unwatered by artificial means; generally deposits in present riverbeds.

bakerite
 * A monoclinic mineral, Ca (sub 4) B (sub 4) (BO (sub 4) )(SiO (sub 4) ) (sub 3) (OH) (sub 3) .H (sub 2) O ; gadolinite group; in white compact nodules resembling marble or unglazed porcelain; in the Mohave Desert, CA.

baking
 * a. A stage in the heating of a clay when the clay particles have lost plasticity and have formed a moderately hard mass composed of particles adhering together, the mass remaining porous. See also: vitrifying.

b. The process of firing shaped clay articles in kilns, in order to give the clay permanent hardness. c. Heating to a low temperature in order to remove gases. d. The hardening of rock material by heat from magmatic intrusions or lava flows. Prolonged baking leads to contact-metamorphic effects.

bal
 * A Cornish name for a mine; a cluster of mines.

balance
 * a. The counterpoise or weight attached by cable to the drum of a winding engine to balance the weight of the cage and hoisting cable and thus assist the engine in lifting the load out of the shaft.

b. An instrument for weighing. c. See: assay balance; balance pit. d. A beam device specif. designed and calibrated to determine specific gravity by weighing methods, as in determining the specific gravity of drilling mud.

balance bob
 * A counterbalance to take the excess weight of the pitwork, or timber beams, in a shaft; used with the Cornish type of reciprocating pump.

balance brow
 * a. A self-acting inclined plane down which the cars of coal are lowered and the empties elevated upon a carriage or platform. Also called balance plane; back balance.

b. Eng. An inclined roadway in which a balance is used to assist the haulage. Also called dilly brow.

balance car
 * a. In quarrying, a car loaded with iron or stone and connected by means of a steel cable with a channeling machine operating on an inclined track. Its purpose is to counteract the force of gravity and thus enable the channeling machine to operate with equal ease uphill and downhill.

b. A small weighted truck mounted upon a short inclined track, and carrying a sheave around which the rope of an endless haulage system passes as it winds off the drum.

balanced cutter chain
 * A cutter chain that has the same number of bottom and top picks. It usually cuts more freely in hard material and is often used for cutting at higher than floor level. See also: unbalanced cutter chain.

balanced direct-rope haulage
 * A modified form of direct-rope haulage, in which a power-driven reversible pulley (surge pulley) is used instead of a drum. The full trams are hauled up on one end of the rope while the empties go down on the other end. It involves a double track or a bypass midway on the haulage plane. The descent of the empty trams assists in balancing the load being hauled upwards.

balanced draft
 * Applied to combustion units in which forced and induced drafts are adjusted to give atmospheric pressure in the combustion chamber to avoid the infiltration of unwanted cold air.

balanced hoisting
 * Arrangement of cages or skips in mine shaft in which the winding drum raises one and at the same time lowers the other, thus reducing power consumption. See also: balanced winding.

balanced ventilation
 * A system of ventilation in which the districts (each with its separate split) are so arranged with regard to length and resistance, that the use of ventilation regulators is unnecessary. Regulators, although sometimes unavoidable, reduce the efficiency and increase the power required to ventilate the mine.

balanced vibrating conveyor
 * A vibrating conveyor in which the center of gravity of the complete assembly is held constant by having movement of the trough offset by opposite movement of some other element.

balanced winding
 * The conventional method of winding in a mine shaft. As the cage containing the loaded cars ascends, the other cage containing the empties descends, and thus the cages and cars are balanced. Balanced winding also implies the use of a balance rope, and thus, ignoring friction, the only load to be hoisted is the coal or mineral. See also: winding; balanced hoisting.

balance pit
 * Eng. A pit or shaft in which a balance (counterweight) rises and falls. See also: balance.

balance plane
 * See: balance brow.

balance rope
 * A steel-wire rope, generally of the same weight per foot as the main winding rope, that is attached to the bottom of the cages, and extends down to form a loop in the shaft bottom or sump. Its function is to balance out the difference in weight of the upgoing or downgoing main ropes during the wind. See also: winding.

balance sheet
 * A record showing the present financial obligations and resources of the company, in terms of cost or book value.

balance shot
 * In coal mining, a shot for which the drill hole is parallel to the face of the coal that is to be broken by it.

balas
 * See: balas ruby.

balas ruby
 * A pale rose-red or orange variety of spinel in Badakhshan (Balascia) Province of northern Afghanistan. Syn: balas; ballas; false ruby.

balata belt
 * A belt with normal multi-ply construction, and in which balata is used to impregnate the plies and provide cover. It cannot be used in high temperatures but possesses a very high resistance to water absorption and is thus well suited for wet conditions.

Balbach process
 * Electrolytic separation of gold from silver, using the alloy as anode, graphite plate cathodes, and silver nitrate solution as bath.

bald
 * Without framing; said of a mine timber that has a flat end.

bald-headed anticline
 * An anticline whose crest has been eroded prior to deposition of an unconformably overlying sedimentary unit. CF: breached anticline.

balistite
 * See: ballistite.

balkstone
 * a. Eng. A provincial name given to an impure stratified limestone.

b. Sandstone used for whetstone. Also called balkerstone.

ball
 * a. A rounded mass of spongy iron, prepared in a puddling furnace; a loup.

b. A mass of tempered fire clay, used for forming the crucible in crucible-steel production. See also: ballstone.

ball-and-socket reamer
 * A borehole-reaming device consisting of a bit attached to a ball-and-socket or a knuckle-joint member, that in turn is connected to the drill rods and used in borehole-deviation drilling. Also called arc cutter.

ball and test
 * A deep well pump valve in which a ball fits into a seat and prevents the backflow of oil or water. Each standing valve and each traveling valve has a ball and seat.

ballas
 * a. A hard, spherical aggregate of many very small diamond crystals, usually cryptocrystalline, arranged radially and more or less concentrically around a central point. Because of their structure, ballas are classed as industrials that are occasionally used in diamond-drill bits and other diamond tools. See also: shot bort.

b. A dense, globular aggregate of minute diamond crystals, having a confused radial or granular structure lacking through-going cleavage planes, giving it a toughness that makes it useful as an "industrial diamond". CF: bort; carbonado. c. A term incorrectly applied to a rounded, single crystal of diamond. d. See: balas ruby.

ballast
 * a. Broken stone, gravel, water, or other heavy material used to provide weight in a ship or other machine and therefore improve its stability or control its draft. Jettisoned ballast may be found in samples of marine sediments.

b. Gravel, broken stone, expanded slag, or similar material used as a foundation for roads, esp. that laid in the roadbed of a railroad to provide a firm bed for the ties, distribute the load, and hold the track in line, as well as to facilitate drainage.

ballast car
 * A freight car (as for carrying ballast) that may be unloaded from the side or bottom.

ballast engine
 * A steam engine used in excavating and for digging and raising stones and gravel for ballast.

ballast shovel
 * A spoon-pointed iron shovel having a thick body.

ball bearing
 * A friction-reducing device consisting of hard steel balls in a circular race; also applied to some pieces of equipment, such as a swivel-type double-tube core barrel, in diamond drilling using ball bearings as load-bearing members on rotating parts. See also: bearing.

ball burnishing
 * a. See also: ball sizing.

b. Removing burrs and polishing small stampings and small machined parts by tumbling.

ball clay
 * A highly plastic, sometimes refractory clay, commonly characterized by the presence of organic matter, having unfired colors ranging from light buff to various shades of gray, and used as a bonding constituent of ceramic wares; pipe clay. It has high wet and dry strength, long vitrification range, and high firing shrinkage. Ball clay is so named because of the early English practice of rolling the clay into balls weighing 30 to 50 lb (13 to 22 kg) and having diameters of about 10 in (25 cm).

ballers
 * White sand with large spheroidal masses of calciferous sandstone called sand ballers or giants' marbles, some being 3 to 6 ft (approx. 1 to 2 m) in diameter. (Possibly a variant of "bollars," a dialect form of boulders.)

ball grinder
 * A pulverizer or disintegrator consisting of metal balls enclosed in a rotating cylinder.

ball head
 * See: ball stamp.

balling
 * a. A process that occurs in the cementite constituent of steels on prolonged annealing at 650 to 700 degrees C.

b. The operation of forming balls in a puddling furnace. Syn: nodulizing.

balling formation
 * Rock or formations that, when drilled, produce cuttings and sludge that tend to collect on, and adhere to, borehole walls and drill-stem equipment in sticky or gummy masses. CF: gummy; sticky.

balling furnace
 * a. A kind of reverberatory furnace used in alkali works.

b. A furnace in which piles or fagots of wrought iron are placed to be heated preparatory to rolling.

balling tool
 * A tool used in collecting the iron in a puddling furnace into a mass, preparatory to taking it to the hammer or squeezer; a rabble.

ball ironstone
 * a. A sedimentary rock containing large argillaceous nodules of ironstone.

b. Nodular iron ore.

ballistic mortar test
 * A laboratory instrument used for measuring the relative weight strength of an explosive material. Also, a test in which a standard weight of explosive is placed within a small borehole fitted with a projectile. The mortar, suspended on a pendulum, recoils upon detonation. The recoil is a measure of the weight strength in percentage (relative to a standard whose value is 100) or pendulum deflection.

ballistite
 * A smokeless powder consisting essentially of soluble cellulose nitrates and nitroglycerin in approx. equal parts. Syn: balistite.

ball jasper
 * a. Jasper showing concentric red and yellow bands.

b. Jasper occurring in spherical masses.

ball mill
 * supported by a frame or shaft, in which nonmetallic materials are ground using various types of grinding media such as quartz pebbles, porcelain balls, etc. Syn: air-swept ball mill. See also: Abbe tube mill; cannonball mill; jar mill.

ball mill grindability test
 * Crushed particles of a given size range are placed in a ball mill; the reduction in size of particles for a given number of revolutions of the mill is interpreted in terms of a grindability index.

ball milling
 * A method of grinding and mixing material, with or without liquid, in a rotating cylinder or conical mill partially filled with grinding media such as balls or pebbles.

ball mill method
 * A grindability method based on the principle that all coals are ground to the same fineness, about that required for pulverized fuels, and then using the relative amounts of energy required for this reduction in size as a measure of grindability.

Ball-Norton magnetic separator
 * Dry separator for coarse ore, in which one or two nonmagnetic drums rotate outside a series of fixed magnets alternating in polarity.

balls
 * a. Common name for nodules, esp. of ironstone.

b. In fine grinding, crushing bodies used in a ball mill. Cast or forged iron or steel, or alloy of iron with molybdenum or nickel, are used, mainly spherical; various other shapes are favored locally, e.g., concave.

ball sizing
 * Sizing and finishing a hole by forcing a ball of suitable size, finish, and hardness through the hole or by using a burnishing bar or broach consisting of a series of spherical bands of gradually increasing size coaxially arranged. Also called ball burnishing, and sometimes ball broaching.

ball stamp
 * A rock-crushing stamp whose stem is the piston rod of a steam cylinder. Syn: ball head.

ballstone
 * a. An ancient term for ironstone, North Staffordshire, U.K.

b. A large crystalline mass of limestone containing coral in position of growth, surrounded by shale and impure bedded limestone. See also: caballa ball. c. A nodule or large rounded lump of rock in a stratified unit; specif. an ironstone nodule in a coal measure. Syn: ball.

ball vein
 * A stratum in which siderite concretions occur; also, the ore itself.

bally seating
 * Underclay with nodular concretions.

balmaiden
 * Corn. A woman employed in the mines.

balnstone
 * Eng. Stone in the roof of a coal seam; roof stone.

baltimorite
 * A grayish-green and silky, fibrous, or splintery variety of serpentine; near Baltimore, MD. See also: antigorite.

banakite
 * A basaltic rock composed of olivine and clinopyroxene phenocrysts in a groundmass of labradorite with alkali feldspar rims, olivine, clinopyroxene, some leucite, and possibly quartz. Banakite grades into shoshonite with an increase in olivine and clinopyroxene and with less alkali feldspar, and into absarokite with more olivine and clinopyroxene. It was named by Iddings in 1895 from the Bannock (or Robber) Indians.

banalsite
 * An orthorhombic mineral, BaNa (sub 2) Al (sub 4) Si (sub 4) O (sub 16) ; feldspar group.

band
 * a. Shale or other rock interstratified with coal, e.g., dirt band, sulfur band, etc.

b. A thin stratum or lamina of conspicuous lithology or color. A group of such layers is described as being banded. CF: parting. c. Any well-defined and widespread thin rock deposit that is of value in correlation. d. Slate or other rock interstratified with coal, commonly called middle band in Arkansas; also, dirt band, sulfur band, or other band, as the case may be. e. Applied to a stratum or lamina conspicuous because it differs in color from adjacent layers; a group of layers displaying color differences is described as being banded.

band chain
 * A steel or invar tape of a minimum length of 100 ft (30.5 m) used for accurate surveying, graduated in feet. See also: reglette.

band conveyor
 * See: belt conveyor.

banded
 * The property of rocks having thin and nearly parallel bands of different textures, colors, or minerals. Banded coal has alternating bands of different types.

banded agate
 * Agate in colors disposed in parallel or subparallel bands, more or less wavy or sinuous. Most agate in the trade is dyed, and bands are of differing tones due to varying capacity to absorb the dye. See also: agate; onyx.

banded coal
 * a. The common variety of bituminous and subbituminous coal. It consists of a sequence of irregularly alternating layers or lenses of homogeneous black material having a brilliant vitreous luster; grayish-black, less brilliant, striated material usually of silky luster; and generally thinner bands or lenses of soft, powdery, and fibrous particles of mineral charcoal. The difference in luster of the bands is greater in bituminous than in subbituminous coal. Also called bright-banded coal; common-banded coal.

b. Coal composed of roughly parallel, dull and bright layers.

banded differentiate
 * Any igneous rock made up of bands of differing chemical or mineral composition, usually an alternation of two rock types; a layered intrusion. The structure has been attributed to rhythmic crystal settling during convection.

banded ingredient
 * One of the four distinctive and visibly differing portions forming the mass of an ordinary bituminous coal that can be recognized and separated macroscopically by hand, and microscopically in thin sections, and that are not, in themselves, chemical entities; i.e., vitrain, clarain, fusain, and durain. See also: rock type.

banded iron formation
 * Iron formation that shows marked banding, generally of iron-rich minerals and chert or fine-grained quartz. Abbrev: BIF.

banded ironstone
 * A term used in South Africa for iron formation consisting essentially of iron oxides and chert occurring in prominent layers or bands of brown or red and black. This usage of the term ironstone is at variance with that applied in the United States and elsewhere. Syn: ironstone.

banded obsidian
 * Obsidian with differently colored irregular bands.

banded ore
 * Ore composed of bands as layers that may be composed of the same minerals differing in color, textures, or proportions, or they may be composed of different minerals. Syn: banded texture.

banded peat
 * Peat composed of bands of vegetable debris alternating with bands of sapropelic matter.

banded-quartz hematite
 * See: itabirite.

banded quartz-hematite ore
 * Braz. In the Itabira Region of Minas Gerais, schistose, specular hematite forming alternate bands with sugary quartz. Some of the beds are auriferous and contain gold-palladium alloys with manganese oxides, native copper, and talc. Writers have given the rocks various names, such as iron-glance schist, jacutinga, quartz itabirite, and bandererz.

banded structure
 * a. An outcrop feature developed in igneous and metamorphic rocks as a result of alternation of layers, stripes, flat lenses, or streaks differing conspicuously in mineral composition and/or texture.

b. A term applied to veins having distinct layers or bands. This may be due to successive periods of deposition or replacement of some earlier rock. c. A structure developed in many igneous and metamorphic rocks owing to layers that differ noticeably in mineral composition or texture. d. A segregated structure of nearly parallel bands aligned in the direction of working.

banded texture
 * See: banded ore.

banded vein
 * A vein made up of layers of different minerals parallel with the walls. Also called ribbon vein.

band scale
 * An arrangement by which colliers are paid an agreed sum for removing a dirt band, in addition to the usual tonnage rate. The payment varies with the thickness of the band.

band wander
 * In concentration on shaking table, the movement of a segregated band of mineral so that it no longer discharges from the table deck at the desired point and therefore is not correctly collected. See also: wander.

bandylite
 * A tetragonal mineral, CuB(OH) (sub 4) Cl ; occurs as dark blue crystals in Chile.

bandy metal
 * Shale with thin sandstone bands.

bank
 * a. A large pile of mineral material on the ground surface, as in heap leaching.

b. Several like pieces of equipment set close together, as a bank of flotation cells, hydrocyclones, or generators. c. The surface around the mouth of a shaft. d. The whole or sometimes only one side or one end of a working place underground. e. A hill or brow. f. A road along the coal face formed by the coal on one side and the waste or packs on the other; thus, a double-unit face has a right and left bank. g. A generally steeply sloping mass of any earthy or rock material rising above the digging level from which the soil or rock is to be extracted from its natural or blasted position in an open-pit mine or quarry. Syn: bench face. h. Terracelike bench from which ore is obtained in an open-pit mine.

Banka drill
 * A portable, manually operated system used in prospecting alluvial deposits to depths of 50 ft (15.2 m) or more. Also known as an Empire drill.

bank claim
 * A mining claim on the bank of a stream.

bank coal
 * Coal contained in, and sometimes salvaged from, the bank.

bank engine
 * Eng. An engine at the mouth of a mine shaft.

banker off
 * Aust. The worker who attends to taking skips off the cage.

banket
 * a. A general term for a compact, siliceous conglomerate of vein-quartz pebbles about the size of a pigeon's egg, embedded in a quartzitic matrix. The term was originally applied in the Witwatersrand area of South Africa to the mildly metamorphosed gold-bearing conglomerates containing muffin-shaped quartz pebbles and resembling an almond cake made by the Boers. Etymol: Afrikaans, a kind of confectionery.

b. Originally applied by the Dutch settlers to the gold-bearing conglomerates of the Witwatersrand. It is now used more widely for similar conglomerates and conglomeratic quartzites.

bank gravel
 * Gravel found in natural deposits, usually more or less intermixed with sand, silt, or clay.

bank head
 * a. The upper end of an inclined plane, next to the engine or drum, made nearly level.

b. The mouth and immediate environs of a coal mine.

bank height
 * The vertical height of a bank as measured between its highest point or crest and its toe at the digging level or bench. CF: berm. Also called: bench height; digging height.

banking
 * a. The bringing of a cage to a stop at the rail level (the pit top or bank) and the replacement of loaded mine cars by empty ones and the release of the cage for its return journey.

b. Closing down a blast furnace which is still full of burden.

bank measure
 * a. The quantity of an excavation measured in place in the bank before being disturbed.

b. Volume of soil or rock in its original place in the ground.

bank mining
 * Surface mining in which the material mined is removed from above the surrounding land surface.

bank of cells
 * A row of flotation cells in line.

bank of ovens
 * A row of ovens for converting coal into coke.

bank protection
 * Devices for minimizing scour. These include brushwood held in place by wooden pegs, embankments, grass and withy planting, groins, mattresses, revetments, and riprap.

bank pump
 * An auxiliary pump placed on the bank of a stream or a lake and used to pump water to a distant drill. Also called supply pump.

bank right
 * The right to divert water for working a bank claim.

bank slope
 * The angle, measured in degrees of deviation from the horizontal, at which the earthy or rock material will stand in an excavated, terracelike cut in an open-pit mine or quarry. Syn: bench slope.

bank slope stability
 * A slope is subject to the influence of gravity and possible pressure of ground water, which tend to cause sliding or caving. It is also subject to surface erosion from running water, wind, and alternate freezing and thawing, or wetting and drying. Weathering causes changes in particle size and composition. Bank slope stability can be attained by benching, by growth of vegetation, and by artificial protections, such as masonry walls, drainage systems to intercept or remove ground water, and fences to catch rolling pieces. See also: stability.

banksman
 * The person in charge of the shaft and cage or skip at the surface of a colliery; the person at the surface who operates the signals from the cage or skip to the winding engineman. See also: cager.

bank water
 * In placer mining, applied to streams brought to the pit in ditches, not under pressure.

bankwork
 * Eng. A system of working coal in South Yorkshire.

bank yards
 * Yards of soil or rock measured in its original position, before digging.

banos
 * Mex. Water collected in old mine workings.

banqueria
 * Bol. In alluvial mining, a thick bed of blocks of granite, schists, and quartz.

bantams
 * Small pebbles of a banded garnet-quartz rock; usually associated with diamond in the concentrate obtained when washing the diamond-bearing gravels from the Vaal River in the Republic of South Africa. The occurrence of bantams in a gravel deposit is considered a good indicator of diamond.

baotite
 * A tetragonal mineral, Ba (sub 4) (Ti,Nb) (sub 8) Si (sub 4) O (sub 28) Cl.

bar
 * a. A placer deposit, generally submerged, in the slack portion of a stream. Also, an accumulation of gravel along the banks of a stream; bar diggings.

b. A mass of inferior rock in a workable deposit of granite. c. A fault across a coal seam or orebody. d. A banded ferruginous rock; specif. jaspilite. e. A vein or dike crossing a lode. f. Any band of hard rock crossing a lode. g. A unit of pressure equal to 1,000,000 dyn/cm (super 2), 1,000 mb (100 kPa), or 29.53 in (750 mm) of mercury. h. A bank of sand, gravel, or other matter, esp. at the mouth of a river or harbor, often obstructing navigation. i. An offshore ridge or mound of sand, gravel, or other unconsolidated material submerged at least at high tide, esp. at the mouth of a river or estuary, or lying a short distance from, and usually parallel to, the beach. j. A drilling or tamping rod. k. A strap or beam used to support the roof between two props or other supports. l. A length of steel pipe equipped with a flat cap at one end and a jackscrew on the opposite end by means of which the pipe may be wedged securely in a vertical or horizontal position across an underground workplace to serve as a base on which a small diamond or rock drill may be mounted. Syn: drifter bar; drill bar; drill column. m. A heavy steel rod with either pointed or flattened ends used as a pry or as a tool by miners to dislodge loose rock in roof or sidewalls of an underground workplace. Syn: scaling bar. n. A piece of material thicker than sheet, long in proportion to its width or thickness, and whose width-thickness ratio is much smaller than that of sheet or plate, as low as unity for squares and rounds.

baralyme
 * A compressed pill consisting of a blended mixture of barium octohydrate and calcium hydroxide. It is used as a carbon dioxide absorbent in rebreathing (diving) systems.

bararite
 * A hexagonal mineral, (NH (sub 4) ) (sub 2) SiF (sub 6) ; dimorphous with cryptohalite; occurs over a burning coal seam.

bar-belt conveyor
 * A conveyor similar to a plate-belt conveyor but in which spaced steel rods arranged transversely are employed in place of the steel plates.

barbertonite
 * A hexagonal mineral, Mg (sub 6) Cr (sub 2) (CO (sub 3) )(OH) (sub 16) .4H (sub 2) O ; manasseite group; rose-pink to violet; dimorphous with stichtite.

barbosalite
 * A hydrous ferrous ferric phosphate, Fe (super 2+) Fe (super 3+) (sub 2) (PO (sub 4) ) (sub 2) (OH) (sub 2) ; occurs as black grains from Brazil. Syn: ferro-ferri-lazulite.

bar channeler
 * A reciprocating drill mounted on a bar by means of which holes are drilled close together in line by shifting the drill from point to point along the bar. Thereafter, the webs between the holes are removed with a reciprocating chisel-pointed broaching tool that is substituted for the drill. This method of channeling is generally employed in the harder rocks, such as granites.

bar coal cutter
 * A coal cutter in which the cutting member was a projecting rotating bar armed with picks throughout its length. The bar cut a kerf in the seam as the machine traveled along the face. The first patent for a bar machine was taken out in 1856. The cutter is now obsolete.

bar diggings
 * A term applied in the Western United States to diggings for gold or other precious minerals located on a bar or in the shallows of a stream, and worked when the water is low. See also: bar mining.

bar drill
 * A small diamond- or other-type rock drill mounted on a bar and used in an underground workplace. Also called bar and used in an underground workbar rig.

bare
 * a. To cut coal by hand; to hole by hand.

b. The uncased portion of borehole. Also called called barefoot; blank; naked; open; open hole. See also: blank hole. c. To remove overburden. d. Eng. To strip or cut by the side of a fault, boundary, etc.; to make bare.

barefoot
 * Said of an oil well without a liner in the oil-bearing rock. See also: blank hole.

bare motor
 * A motor without a pulley, belt-tightening base, or slide rails.

barequear
 * Colom. In placer mining, to extract as much of the pay gravel as possible, without method, leaving the overburden untouched.

barequeo
 * Colom. Extracting the rich ore by crude means.

barequero
 * Colom. A placer miner who uses crude methods of alluvial washing. A spoiler.

barer
 * A worker who removes surface soil or overburdens in a quarry.

barfe Saturday
 * N. of Eng. The Saturday on which wages are not paid.

bar flight conveyor
 * See: drag-chain conveyor; flight conveyor.

barge loader
 * In the quarry industry, a laborer who controls the movement of a barge in a river as it is loaded with crushed rock.

barges
 * Scot. Sheets of iron, zinc, or wood, used in wet shafts or workings for diverting the water to one side.

bar grizzly
 * A series of spaced bars, rails, pipes, or other members used for rough sizing of bulk material passed across it to allow smaller pieces to drop through the spaces. See also: grizzly.

barilla
 * An impure sodium carbonate and sulfate obtained by burning various species of land or marine plants; soda ash. See also: copper barilla; coro-coro.

baring
 * a. The small coal made in undercutting coal seams.

b. A making bare; an uncovering. See also: strip. c. The surface soil and useless strata overlying a seam of coal, clay, ironstone, etc., that have to be removed preparatory to working the mineral. See: overburden.

barite
 * a. An orthorhombic mineral, 4[BaSO (sub 4) ] ; has nearly pseudocubic cleavage; occurs as interpenetrant masses of crystals with sand and clay (desert roses); sp gr, 4.5; in veins or in residual masses on limestone; the principal source of barium. Syn: barytes; dreelite; heavy spar; cawk.

b. The mineral group anglesite, barite, and celestine.

barite rosette
 * See: petrified rose.

barium
 * A silvery-white, metallic element, belonging to the alkaline earth group. Symbol, Ba. Found chiefly in barite or heavy spar and witherite. All barium compounds that are water or acid soluble are poisonous. Used in paint, X-ray diagnostic work, glassmaking, oilwell drilling fluids, and pyrotechny.

barium feldspar
 * See: paracelsian.

Barkhausen effect
 * Observed result of magnetizing a ferromagnetic substance by means of a slow magnetic field increase. Orientation of domains proceeds in abrupt steps.

barley
 * A stream size of anthracite known also as buckwheat No. 3, sized on a round punched plate. It passes through 1/4-in (6.4-mm) holes. At some mines, it has to pass over 3/32-in (2.4-mm) holes and at others over 1/16-in (1.6-mm) holes. The American Society of Mechanical Engineers has recommended that with a screen with circular holes, barley shall pass through 3/16-in (4.8-mm) holes and pass over 3/32-in holes. See also: anthracite coal sizes; bird's-eye.

bar mining
 * The mining of river bars, usually between low and high waters, although the stream is sometimes deflected and the bar worked below water level. See also: bar diggings.

barnesite
 * a. A monoclinic mineral, (Na,Ca) (sub 2) V (sub 6) O (sub 16) .3H (sub 2) O.

b. Trademark for a rare-earth oxide used in glass polishing.

barograph
 * A barometer that makes a continuous record of changes in atmospheric pressure. It is usually an aneroid type. See also: barometer.

barometer
 * An instrument that is used to measure atmospheric pressure. It may be either a mercury barometer or an aneroid barometer. See also: barograph.

barometric leg
 * In filtering system, use of a loop more than 30 ft (9.1 m) high between receiving vessel and vacuum pump, to protect latter against carryover of liquid.

barometric leveling
 * A type of indirect leveling in which differences of elevation are determined from differences of atmospheric pressure observed with altimeters or barometers.

barometric pressure
 * The barometric pressure of the air at any point is that exerted by the weight of the atmosphere above that point. It therefore varies with the elevation of the point above or the depth below sea level. Barometric pressure is measured by the mercury barometer, and is of the order of 30 in (762 mm) of mercury at sea level.

baroque
 * a. Any pearl of very irregular form.

b. A baroque pearl; said of a pearl, or of a tumble-polished gem material, of irregular shape.

barotrauma
 * A generic term for injury caused by pressure. Although squeeze is a colloquialism, it is an excellent descriptive term for all of the phenomena that occur when a rigid closed space within the body or on its surface fails to equalize with external pressure during descent, or is for some reason vented to lower pressure than that acting at the depth.

barranca
 * A precipice; as used in some parts of Spanish America, a ravine or small canyon. Also spelled barranco.

barrandite
 * A mineral intermediate between strengite and variscite.

barrel
 * a. As used in the petroleum industry, a volumetric unit of measurement equivalent to 42 U.S. gal (159.0 L).

b. The cylindrical part of a pump from which the movement of the piston causes a liquid or gas to be forcibly ejected. Also, the cylindrical part of a hydraulic jack or of a hydraulic-feed mechanism on a diamond drill. c. The drum of a hoist. d. A cylindrical container or drum having a capacity of 55 gal (208.2 L). e. The water passage in a culvert. f. Commonly, although incorrectly, used as a syn. for core barrel. See also: drum.

barrel copper
 * Pieces of native copper occurring in sizes large enough to be extracted from the gangue, and of sufficient purity to be smelted without mechanical concentration. Syn: barrel work.

barrel of oil
 * A volumetric unit of measurement equivalent to 42 U.S. gal (159.0 L).

barrel washer
 * A washer comprising a cylinder rotating slowly about an axis that is slightly inclined to the horizontal, and into which the raw coal, with a current of water or of a suspension, is fed near its upper end. The clean coal is carried by the water or suspension to the lower end of the cylinder over a scroll that conveys the reject to the upper end of the cylinder.

barrel work
 * Syn: barrel copper. Used in the Lake Superior mining region.

barren
 * a. In leaching ores, said of a chemical solution from which valuable solute has been removed by precipitation, ion exchange, or solvent extraction before reuse.

b. Said of rock or vein material containing no minerals of value, or of strata without coal, or containing coal in seams too thin to be workable.

barren ground
 * Strata containing seams of coal that are not of a workable thickness. In metal mining, ground that does not contain ore. See also: dead bed.CF: dead ground.

barren hole
 * See: blank hole.

barren mine
 * Coal measures without workable seams. o�         *�         �P� �       � � DICTIONARY TERMS:barren mine A mine may be fully developed and yet, A mine may be fully developed and yet, owing to the barrenness of the ore, it would be impossible to work it with profit.

barren solution
 * A solution in hydrometallurgical treatment from which all possible valuable constituents have been removed; it is usually recycled back to plant for reuse in process. See also: cyanide.

barricade
 * a. The process of building a set of barriers to isolate a sufficient quantity of good air to protect mine workers from the asphyxiating gases formed after a fire or explosion. Miners wait behind the barrier until rescued. Used as an alternative to an escape attempt.

b. An artificial mound of earth, usually as high as the eaves of a magazine roof, that is erected to deflect the force of an explosion upward and to protect the enclosed building from flying objects. c. Timber formwork to contain the material during hydraulic flushing in steep ore workings.

barrier
 * Blocks of coal left between the workings of different mine owners and within those of a particular mine for safety and the reduction of operational costs. It helps to prevent disasters of inundation by water, of explosions, or fire involving an adjacent mine or another part of a mine and to prevent water running from one mine to another or from one section to another of the same mine. See also: barrier pillar.

barrier gate
 * Eng. See: tailgate.

barrier materials
 * Materials such as lead and concrete that are used for protection from X-rays or gamma rays in radiographic installations.

barrier pillar
 * a. A solid block or rib of coal, etc., left unworked between two collieries or mines for security against accidents arising from an influx of water. See also: barrier; pillar; barrier pillar.

b. Any large pillar entirely or relatively unbroken by roadways or airways that is left around a property to protect it against water and squeezes from adjacent property, or to protect the latter property in a similar manner. c. Incorrectly used for a similar pillar left to protect a roadway or airway, or group of roadways or airways, or a panel of rooms from a squeeze.

barrier system
 * N. of Eng. An approved method of working a colliery by pillar and stall, where solid ribs or barriers of coal are left in between working places.

bar rig
 * A small diamond or other rock drill designed to be mounted and used on a bar. Also called bar drill.

barring
 * The end and side timber bars used for supporting a rectangular shaft. The bars are notched into one another to form a rectangular set of timber. Common sizes are from 9 to 12 in (23 to 30.5 cm) deep and from 3 to 6 in (7.6 to 15.2 cm) thick and may be made from larch, white pine, or red pine. See also: cribbing; steel rectangular shaft supports.

barring down
 * a. Loosening ore in a bin by means of a bar, so it will flow through the chute.

b. Prying off loose rock after blasting to prevent danger of fall.

barrings
 * A general term for the setting of bars of timber for supporting underground roadways or shafts.

barring scrap
 * Prying adhering scrap metal from runners, ladles, or skimmers.

barro
 * A Spanish and South American term for clay, loam, marl, or the overburden of alluvial gold deposits.

barroisite
 * A dark green amphibole intermediate between hornblende and glaucophane.

barrow
 * a. A wicker basket in which salt is put to drain.

b. A box with two handles at one end and a wheel at the other. c. A vehicle in which ore, coal, etc., is wheeled; a push cart.

barrowman
 * In mining, one who pushes shallow-bodied cars (barrows) or wheelbarrows used for transporting coal or ore along underground haulageways that are too low for ordinary mine cars. Also called buggyman.

barrowway
 * a. A level through which coal or ore is wheeled.

b. Rails laid between the flat or siding and the coal face.

Barry mining
 * See: Nottingham system.

barsanovite
 * See: eudialyte.

bar screen
 * See: grizzly.

bar timbering
 * A method of timbering mine roadways by means of horizontal and upright bars. See also: timber set.

bar tin
 * Solid, commercial tin.

Bartlett table
 * A three-shelf table driven by an eccentric that gives it a vanning motion. Ore and water are fed on the upper shelf, giving two products, heads and tailings. The latter are retreated on the second shelf, and the tailings go to the third or lower shelf for retreatment.

Barvoys process
 * A sink-float process in which the medium is a suspension of clay from the raw coal and minus 200- or 300-mesh barite in water, with the volume of the clay usually equal to about twice that of the barite. Barite clay and coal suspensions can be regulated to get effective washing gravities from 1.2 to 1.8. Sizes from run-of-mine to one-eighth inch may be cleaned by this process, which has been widely adopted in Europe. Also known as the Sophia-Jacoba process in German publications.

barylite
 * An orthorhombic mineral, BaBe (sub 2) Si (sub 2) O (sub 7) ; forms hard (6 to 7 on the Mohs scale), colorless crystals; at Laangban, Sweden; Franklin, NJ; and Park County, CO.

barysilite
 * A white trigonal mineral, Pb (sub 8) Mn(Si (sub 2) O (sub 7) ) (sub 3) ; occurs at Laangban, Sweden, and Franklin, NJ.

barysphere
 * The interior of the Earth beneath the lithosphere, including both the mantle and the core. However, it is sometimes used to refer only to the core or only to the mantle. Syn: centrosphere.

baryta
 * Barium oxide; BaO.

barytes
 * See: barite.

barytocalcite
 * a. A monoclinic mineral, BaCa(CO (sub 3) ) (sub 2) ; trimorphous with alstonite and paralstonite.

b. A mixture of calcite and barite.