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

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A hexagonal mineral, BeMg (sub 3) Al (sub 8) O (sub 16) ; hoegbomite group; a dimorph of musgravite; violet-red.


Token, check, tally. Syn: teller. See also: tally.


Translucent to opaque and white to bluish white opaline silica of organic origin (deposited with the joints of a bamboo shoot), valued in the East Indies as a medicine and used in native jewelry. Also spelled tabaschir or tabashir.


A mixture of lime with shells, gravel, or stones in equal proportions, with an equal proportion of water, forming a mass that when dry becomes as hard as rock; a substitute for bricks or stone in building.


Trade name for a variety of solid asphalt found in veins in Tabby Canyon, UT.


a. See: rotary table. b. A concentrating machine with a flat surface for separating finely crushed particles of ore or coal from gangue.

c. In placer mining, a wide, shallow sluice box designed to recover gold or other valuable mineral from screened gravel. See also: undercurrent.

table cut

a. An early style of fashioning diamonds in which opposite points of an octahedron were ground down to squares to form a large cutlet and a larger table, the remaining parts of the eight octahedral faces being polished.

b. A term used somewhat loosely to describe any one of the variations of the "bevel cut," provided it has the usual large table of that cut. Syn: bevel cut.

table diamond

A relatively flat diamond of table cut.

table flotation

Flotation process practiced on a shaking table. Ore or coal is ground, deslimed, conditioned, and fed to table as thick slurry. Flotable particles become glomerules, held together by minute air bubbles and edge adhesion. These roll across and are discharged nearly opposite the feed end. The process is helped by jets of low-pressure air from piping set across table. Tailings work along deck to discharge end.


a. A general term for a broad, elevated region with a nearly level or undulating surface of considerable extent; e.g., South Africa.

b. A plateau bordered by abrupt clifflike edges rising sharply from the surrounding lowland; a mesa.

table spar

See: tabular spar; wollastonite.


Separation of two materials of different densities by passing a dilute suspension over a slightly inclined table having a reciprocal horizontal motion or shake with a slow forward motion and a fast return.


a. Said of a feature having two dimensions that are much larger or longer than the third, such as a dike, or of a geomorphic feature having a flat surface, such as a plateau.

b. Said of the shape of a sedimentary body whose width to thickness ratio is greater than 50:1, but less than 1,000:1 (Krynine, 1948); e.g., a graywacke formation in a geosynclinal deposit. CF: blanket; prism. c. Said of a sedimentary particle whose length is 1.5 to 3 times its thickness (Krynine, 1948). CF: prismatic. d. Said of a metamorphic texture in which a large proportion of grains are tabular and have approximately parallel orientation (Hart, 1977) e. Said of a crystal form that shows one dimension markedly smaller than the other two. f. Tabular crystals, such as wollastonite, may occur in tables, plates, disks, foliae, and scales. g. A mineral showing broad, flat surface, e.g., wollastonite. h. See: tabular deposit. i. Refers to crystals that have three distinctly different dimensions. CF: acicular; anisodesmic; equant.

tabular crystal

A crystal flattened parallel to any face.

tabular deposit

A flat tablelike or stratified bed; e.g., a coal seam. See: tabular.

tabular spar

Wollastonite in tabular form. Syn: table spar.

tabular structure

The structure of a mineral or rock that makes it tend to separate into plates or laminae.

Taby cut

A modified double-spiral cut, the benefits of which are that the holes are located vertically below one another on one and the same line to facilitate drilling.


A monoclinic mineral, Ca (sub 12) Al (sub 2) Si (sub 18) O (sub 51) .18H (sub 2) O .


See: tachymeter; subtense bar.


An instrument for measuring speed. In mining it is used on hoists lifting cages, cars, or skim in shafts or slope.


A trigonal mineral, CaMg (sub 2) Cl (sub 6) .12H (sub 2) O . Also spelled tachydrite or tachhydrite.


A surveying instrument designed for use in the rapid determination from a single observation of the distance, direction, and elevation difference of a distant object; esp. a transit or theodolite with stadia hairs, or an instrument in which the base line for distance measurements is an integral part of the instrument. Syn: multiplying constant; tacheometer.


A method of rapid surveying using the tachymeter; e.g., the stadia method of surveying used in United States.


a. A small pillar of coal.

b. Veinstone; gangue, etc. See also: taking.


Having a rough, catchy surface.


An assemblage of ropes or wire cables and pulleys arranged for hoisting or pulling.

Tacoma process

An electrolytic method for the production of iron powder.


a. A local term used in the Lake Superior iron-bearing district of Minnesota for any bedded ferruginous chert or variously tinted jaspery rock, esp. one that enclosed the Mesabi iron ores (granular hematite); an unleached iron formation containing magnetite, hematite, siderite, and hydrous iron silicates (greenalite, minnesotaite, and stilpnomelane). The term is specif. applied to this rock when the iron content, either banded or disseminated, is at least 25%. Also spelled taconyte.

b. Since World War II, a low-grade iron formation suitable for concentration of magnetite and hematite by fine grinding and magnetic treatment, from which pellets containing 62% to 65% iron can be produced.

taconite ore

A type of highly abrasive iron ore now extensively mined in the United States.


See: taconite.


A rock of complex mineralogical composition, formed by contact metamorphism and metasomatism of carbonate rocks. It is typically coarse-grained and rich in garnet, iron-rich pyroxene, epidote, wollastonite, and scapolite. Approximate syn: skarn. See also: calc-silicate hornfels. CF: garnetite.


A monoclinic mineral, KLiMg (sub 2) Si (sub 4) O (sub 10) F (sub 2) ; mica group; at Narsarsuk, Greenland, and Magnet Cove, AR. Also spelled tainiolite.


An isometric mineral, (Fe,Ni) ; contains 27% to 65% nickel; occurs in iron meteorites as lamellae or strips flanking bands of kamacite. Also called gamma-nickel-iron (face-centered cubic). See also: nickel iron.


A numbered piece that a miner attaches to or places on each car a miner loads. The tag is removed at the tipple where the car is credited to the miner. See also: tally; ticket. CF: wedge rock.

tagged atom

See: tracer.

Tagg's method

a. A graphical method of determining the resistivity of the ground.

b. A method of interpretation of resistivity sounding data obtained with a Wenner array over a two-layered Earth.


See: pseudomalachite.


A line from a crane boom to a clamshell bucket that holds the bucket from spinning out of position.


a. (also plural). The inferior, less valuable, or refuse part of anything; foots, bottoms, dregs; sediment. See also: tailings.

b. The poor grade of ore slime at the lower end of the slime box as it flows from the stamps. c. The unexposed end of a brick or stone in a wall; a tailing. d. The rear of a shovel deck. e. The anchor end of a cable excavator. f. A bar or barrier formed behind a small isle or a skerry. Also called trailing spit; banner bank.

tail anchor

The anchor for a track cable, or the turn point for a backhaul line in a cable excavator.

tail beam

A joist or beam that abuts against the header joist. Syn: tail joist.


a. The boom foot and idler sprocket assembly on a ladder ditcher.

b. The block used to pull a slusher to the face.


See: tailgate.

tail chain

A chain used in mine haulage; also, tail rope.

tail crab

In mining, a crab or winch for operating a tail rope.


a. That part of a mining belt conveyor that consists of the tail section and, when required, a belt takeup, a telescopic section, and a loading station.

b. The end of a conveyor remote from the delivery point. See also: tension end.

tailend loading station

See: loading station.


A subsidiary gate road to a conveyor face as opposed to a main gate. The tailgate commonly acts as the return airway and supplies road to the face. Syn: barrier gate; tailboard. See also: bottom gate.

tail house

The buildings in which tailings are treated.


a. Giving the proper angle, or elevation, in driving the poling boards in a heading.

b. The part of a projecting brick or stone inserted in a wall.

tailing pit

See: catch pit.

tailing pond

Area closed at lower end by constraining wall or dam to which mill effluents are run. Clear water may be returned after settlement in dam, via penstock(s) and piping.


a. The gangue and other refuse material resulting from the washing, concentration, or treatment of ground ore. See also: tail.

b. Those portions of washed ore or coal that are regarded as too poor to be treated further c. Applied to sectional residue, e.g., table tailings, which is the residue from shaking screens and tables. d. The reject from froth flotation cells.

tailings dam

One to which slurry is transported, the solids settling while the liquid may be withdrawn.

tailings machine

A machine for sifting the tailings and collecting the gold from the detritus after it has passed through the washer.

tailings settling tank

A vessel to remove solids from the tailings effluent as in a coal washery. The tank is about 60 ft (18 m) in diameter and 10 ft (3 m) deep. The tailings are fed in at the center with a flocculant. As the suspension travels from the center to overflow at the perimeter of the tank, the solids settle out and the clear water overflows, is collected, and is returned to the washer for reuse.

tailings wheel

A wheel carrying buckets or compartments on the periphery and used in conveying liquid, pulp, or sand from a lower to a higher level.

tail joist

A joist that has one end terminating against a header joist. See: tail beam.


A light carried at the back end of a car, train, trip, or movable machinery.

tail of water

The edge of water standing in mine workings.

tail pipe

The suction pipe of a pump.

tail pulley

a. The terminal pulley at the end of the conveyor opposite the normal discharge end. It is usually an idler pulley but may be a drive pulley.

b. The pulley or roller in the tail or foot section of a belt conveyor around which the belt runs. Also known as foot-section pulley.


A trough or channel used for conveying the tailings; a channel for conducting water away from any plant or works.

tail rope

a. The rope that passes around the return sheave in main-and-tail haulage or a scraper loader layout. See also: main rope.

b. The rope used to draw the empties back into a mine in a tail-rope haulage system. c. A counterbalance rope attached beneath a cage when the cages are hoisted in balance. d. A hemp rope used for moving pumps in shafts.

tail-rope boy

See: tail-rope coupler.

tail-rope coupler

In bituminous coal mining, one who works on a tail-rope haulage system, removing the haulage-cable hook from the rear of a train of empty cars that has been lowered down an inclined haulageway, and attaching the hook to the front of a train of loaded cars to be hauled to the surface. Also called tail-rope boy.

tail-rope engineer

In bituminous coal mining, one who operates a hoisting engine that draws the cable of a tail-rope haulage system used to raise and lower mine cars on tracks between the surface and a level in a mine.

tail rope fireman

In bituminous coal mining, a person who fires the boiler supplying steam for the engine that powers the tail-rope haulage system, a type of cable haulage used to raise and lower cars along an incline between the surface and a level in a mine.

tail-rope haulage

A single track system of rope haulage in which a double-drum haulage engine at the unloading terminal winds the main rope on one drum. The train or trip of cars is connected to the other end of the main rope and also to a tail rope that extends to the inner terminal in the mine, around a tail sheave, and then back over idler sheaves at one side of the haulageway to the other drum at the haulage engine. See also: rope haulage.

tail-rope man

See: tail-rope rider.

tail-rope rider

In bituminous coal mining, one who works on trains of cars hauled by tail-rope haulage system at mine, coupling and uncoupling cars, and hooking and unhooking cable to and from trains. Also called tail-rope man.

tail-rope system

A method of haulage in which one rope--the main rope--is attached to the front end of a trip of cars and another rope--the tail rope--is attached to the rear end of the trip. It is operated by a hoisting engine and two separate drums.


Can. Portion of tailings containing some mineral that cannot be economically removed. This is constantly assayed as it leaves the treatment plant so that recovery can be known and controlled at all times. CF: heads.

tail section

The part of a mining belt conveyor that consists of the tail pulley, the framing, belt idlers if included, and means for attaching a belt takeup.

tail shaft

The shaft in the tail or foot section of a belt or chain conveyor that supports either the tail pulley or the tail sprocket.

tail sheave

a. An arrangement whereby a sheave is placed at the bottom of a shaft, and a rope is fastened to the bottom of one cage and then passed down around the sheave and up to the bottom of the cage in the other compartments; thus practically complete balancing is effected.

b. The pulley around which the tail rope of a scraper loader or main-and-tail haulage passes. See also: turn pulley.

tail swing

The clearance required by the rear of a revolving shovel.

tail-track system

The simplest form of track layout for car or trip loading. In this system, the track can merely be extended down the heading, or it can be turned right or left, and then turned back, U-fashion, in an adjacent heading. The major disadvantage is that trips must come out the same way they go in, meaning increased loss of time unless the changing track is very close.

tail water

The water downstream from a structure, as below a dam.


See: taeniolite.


a. A mineral-bearing area that a mine is permitted to work. Also called holding; parcel; taking.

b. The area or extent of coal that a coal mine owner has the right, under a lease, to mine and extract. See also: concession system; royalty. c. Eng. The extent or area of a lease of mineral property, often several thousand acres. d. Lanc. To show or reveal gas.


Cumb. An outcrop. As a verb, to crop out.

take the air

a. To measure the ventilating current.

b. Applied to a ventilating fan as working well, or working poorly.


a. In a belt-conveyor system, a tensioning device such as a carriage-mounted weight free to run downslope or a takeup pulley with weights hanging vertically below the belt near the feed end.

b. Any device for taking up slack or removing the looseness of parts due to wear or other cause. c. See: chain takeup.

takeup pulley

An idler pulley so mounted that its position is adjustable to accommodate changes in the length of the belt as may be necessary to maintain proper belt tension.


Eng. A mineral-land lease. See also: take; tack.


A surface depression containing clay and evaporites in south-central Asia. Also spelled takir.

Talbot continuous process

A pig iron and ore process that depends upon the rapid oxidation of the impurities contained in pig iron by a liquid, highly ferruginous slag and that is carried out in the basic open-hearth furnace, generally of the tilting type. The essential feature of the process is to retain a certain amount of metal in the furnace (1) to dilute the impurities contained in the additions of pig iron, and (2) to supply the heat necessary to keep the slag very fluid.

Talbot process

A process for protecting the inside of cast-iron pipes with a coating of sand and bitumen.


a. A monoclinic and triclinic mineral, 2[Mg (sub 6) (OH) (sub 4) (Si (sub 8) O (sub 20) )] ; basal cleavage; soft; has a greasy or soapy feel; easily cut with a knife; occurs as hydrothermal alteration of ultramafic rocks, low-grade metamorphism of siliceous dolomites in foliated, granular, or fibrous masses; an insulator, ceramic raw material, and lubricant. Originally spelled talck. See also: steatite; soapstone.

b. In commercial usage, a talcose rock; a rock consisting of talc, tremolite, chlorite, anthophyllite, and related minerals. Syn: talcum.


a. A massive variety of talc.

b. Damourite, a soapy-feeling hydromuscovite.


Resembling talc, as talcoid schist.


a. Pertaining to or containing talc; e.g., talcose schist.

b. Resembling talc; e.g., a talcose rock that is soft and soapy to the touch.

talc schist

A schist in which talc is the dominant schistose mineral. Common associates are mica and quartz.


See: talc; soapstone.


Applied to a series of small bumps or cracking noises within the walls. Bumping, talking, and spitting are signs that the rock is beginning to yield to the stresses and indicate a change in conditions within the rock.

tallow drop

A style of cutting precious stones in which the stone is domed on one or both sides.

tallow peat

Ir. A variety of highly flammable peat.

tallow top

A precious stone with a very rounded front and a flat back.


a. A mark or number placed on every car of coal or ore a miner sends out, usually a metal ticket. By counting these, a tally is made of all the cars the miner sends out. See also: tab; tag; ticket.

b. A brass tag attached to a chain at every tenth link, and so marked or shaped as to enable the position of the tally along the chain to be immediately read.

tally boy

See: tally shouter.


See: chute checker.

tally shouter

A laborer who calls out the number chalked on each loaded mine car, as it is run on scales for weighing, so that the weighmaster can identify for pay purposes the miner who loaded the car. Syn: tally boy.


Rock fragments of any size or shape (usually coarse and angular) derived from and lying at the base of a cliff or very steep, rocky slope. Also, the outward sloping and accumulated heap or mass of such loose broken rock, considered as a unit, and formed chiefly by gravitational falling, rolling, or sliding. See also: scree. Syn: rubble.

talus creep

The slow downslope movement of talus, either individual rock fragments or the mass as a whole.

talus fan

See: alluvial fan.


A very fine-grained, soft, gritty, natural stone found in Scotland.


a. To tightly pack a drilled hole with moist, loose material after the charge has been placed.

b. To fill a charged shothole with clay or other stemming material to confine the force of the explosion. See also: stemming. c. To ram or pound down ballast on a railway track, or road metal. d. See: stem.


a. In bituminous coal mining, one who fills drill holes in which explosives have been charged, by machine driller or miner, with clay or some other tamping material, using a tamping bar. Also called shot tamper.

b. An implement for tamping or compacting material; a tamping iron or tamping bar. Sometimes made of wood, copper, or iron with a copper tip. See also: tamping bar. c. One who tamps. d. A tool for compacting soil in spots not accessible to rollers.


a. The act of inserting and packing explosives and stemming in a shothole. See also: stemmer.

b. The act of packing a drilled hole around a cartridge with fine dirt from the floor of a mine before blasting, to prevent a misdirection of the force of the blast. c. The material placed over a charge in a borehole, to better confine the force of the explosion to the lower part of the hole. d. Ramming down, as of ballast. e. The operation of compacting freshly placed concrete by repeated blows. f. The shaping of a semidry powder, e.g., of refractory material, in a mold by repeated blows delivered mechanically on the top mold plate.

tamping bag

A paper bag that is filled with good stemming material such as sand for use in horizontal and upward-sloping holes. Plastic bags are also available for this purpose. See also: tamp.

tamping bar

A piece of wood the size of a broom handle for pushing explosive cartridges and stemming into shotholes. See also: tamper.

tamping plug

A plug of iron or wood used instead of tamping material to close up a loaded blasthole.

tamping pole

A pole of nonsparking material used to tamp in blast holes. Syn: loading pole.

tamping rod

See: stemmer; stemming rod.

tamping roller

One or more steel drums, fitted with projecting feet, and towed by means of a box frame.

tamping stick

See: stemming rod.


a. A double-axle drive unit for a truck or grader. A bogie.

b. A pair in which one part follows the other.

tandem drive

A three-axle vehicle having two driving axles.

tandem-drive conveyor

A conveyor having a belt drive mechanism in which the conveyor belt is in contact with two drive pulleys, both of which are driven with the same motor.

tandem hoisting

Hoisting in a deep shaft with two skips running in one shaft. The lower skip is suspended from the tail rope of the upper skip. Both are loaded and discharged simultaneously. The upper one discharges at the surface and is loaded at a pocket halfway down the shaft. The lower skip is loaded at the shaft bottom and discharges at the half-way pocket. Thus, the rope on the winding drum is only equal to half the full depth. See also: two-stage hoisting.

tandem hydroseparator

A two-celled hydroseparator with troughs. The raw coal feed is conveyed through a trough by water under pressure where the refuse stratifies to the bottom. The action in the first cell is that of a forceful upward current, which results in the removal of the heavy refuse. In the second cell a lighter current permits the settling of lighter and smaller refuse. The refuse settles to a perforated cell deck where it joins the slowly moving slate bed to the discharge. Refuse discharge is controlled by a refuse gate or hinged plate at the end of the cell bed.

Tandem support system

A trade name for a longwall steel support system. It consists of two 50-st (45-t) chocks in line at right angles to the face and linked together with a double-acting ram. In operation, the front chock is lowered and advanced with the conveyor and reset to the roof; the rear chock is then lowered and brought forward.

tandem unit panel

A longwall conveyor face with two face conveyors of different capacities, one delivering on to the other--tandem fashion. The layout has the disadvantage that the whole tonnage of coal must be transported along the second conveyor, and any breakdown on the second conveyor will affect the output of the entire face.


A small hill covering a residual surface of laterite, frequently ore bearing.


See: bowenite.


Former name for calciovolborthite.


a. A straight line that touches, but does not transect, a given curve or surface at one and only one point; a line that touches a circle and is perpendicular to its radius at the point of contact.

b. The part of a traverse included between the point of tangency (the point in a line survey where a circular curve ends and a tangent begins) of one curve and the point of a curvature (the point in a line survey where a tangent ends and a circular curve begins) of the next curve. c. A great-circle line that is tangent to a parallel of latitude at a township corner in the U.S. Public Land Surveys system. d. A term sometimes applied to a long straight line of a traverse whether or not the termini of the line are points of curve. e. The ratio of the length of the leg opposite an acute angle in a right-angled triangle to the length of the leg adjacent to the angle. Adj. said of a line or surface that meets a curve or surface at only one point.

tangent distance

The distance from the point of curvature to the point of intersection (vertex), or from the point of intersection to the point of tangency. See also: intersection point.

tangential stress

a. Stress parallel to the tangent to the boundary of any opening.

b. See: shear stress.

tangent point

The point at which a curve meets a straight line or another curve.

tangent screw

A very fine, slow-motion screw giving a tangential movement for making the final setting to a precision surveying instrument (such as for completing the alignment of sight on a theodolite or transit by gentle rotation of the reading circle about its axis). CF: Stebinger drum.


A variety of serpentine used by the Maoris for ornaments. Similar to bowenite. See also: bowenite.


A term used by the Maoris of New Zealand for bowenite, a massive variety of antigorite. Also spelled tangiwai or tangawaite.

tangle sheet

Mica with intergrowths of crystals or laminae resulting in books that split well in some places but tear to produce a large proportion of partial films.


a. A large vessel or receptacle, made either of wood or of metal, intended to contain a fluid or gas, as water tank, gasoline tank. Syn: vat.

b. A melting unit, in which the container for the molten glass is constructed from refractory blocks.


a. The act or process of storing oil, etc., in a tank.

b. The price charged or paid for storage in a tank. c. The capacity of a tank or tanks. d. The waste residue deposited in lixiviating vats or tanks.

tank furnace

Essentially a large box of refractory material holding from 6 to 200 st (5.4 to 181 t) of glass, through the sides of which are cut ports fed with a combustile mixture (producer gas and air, coke oven gas and air, or oil spray and air), so that flame sweeps over the glass surface. With the furnace is associated a regenerative or recuperative system for the purpose of recovering part of the heat from the waste gas.

tank station

See: station.


A mineral series ferrotantalite-manganotantalite; unless specified it refers to ferrotantalite, an orthorhombic mineral, FeTa (sub 2) O (sub 6); black; in pegmatites; the main source of tantalum.


A rather brittle, lustrous, hard, heavy, gray metallic element. Symbol, Ta. Occurs principally in the mineral columbite-tantalite, (Fe,Mn)(Nb,Ta) (sub 2) O (sub 6) . Widely used to fabricate chemical process equipment, nuclear reactors, and aircraft and missile parts. Used to make electrolytic capacitors, vacuum furnace parts, and surgical appliances.

tantalum borides

Several borides are known, including the following: Ta B (sub 2) , melting point, 3,200 degrees C; sp gr, 12.5; thermal expansion, 5.5 X 10 (super -6) ; TaB, melting point, 2,400 degrees C; sp gr, 14.3; Ta (sub 3) B (sub 4) , melts incongruently at 2,650 degrees C; sp gr, 13.6.

tantalum nitrides

Two nitrides are known: TaN, melting point, 3,090+ or -50 degrees C; Ta (sub 2) N , which loses nitrogen at 1,900 degrees C.


An orthorhombic mineral, (Y,Ce,Ca)(Ta,Nb,Ti) (sub 2) (O,OH) (sub 6) ; black. Syn: delorenzite.


A possibly triclinic mineral, Ti (sub 2) O (sub 5) .


A blue to violet gem variety of zoisite.


a. To cut or bore into old workings or water-bearing strata for the purpose of proving or extracting gas or water.

b. To intersect with a borehole and withdraw or drain the contained liquid as water from a water-bearing formation or from underground workings. c. To drive one passageway into another. d. To win coal in a new district. e. A threaded cone-shaped fishing tool. It may be either an inside or an outside tap, depending on whether the tap fits into or over the outside of a piece being fished. Syn: tapered tap. f. A quantity of a liquid, as molten metal from a furnace, run out at one time. g. To drain a furnace. h. To remove excess slag from the floor of a pot furnace.

tap bar

A pointed bar by which a blast-furnace tap-hole is opened or the metal in a melting pot, etc., is tested. Syn: tapping bar.


A continuous ribbon or strip of steel, invar, dimensionally stable alloys, specially made cloth, or other suitable material, having a constant cross section and marked with linear graduations, used by surveyors in place of a chain for the measurement of lengths or distances.

tape corrections

These are applied as a routine matter to slope, temperature, sag, standardization, gravity and sea level effect when measuring a length accurately with a tape. See also: precision; tension correction.


A gradual and uniform decrease in size, as a tapered socket, a tapered shaft, a tapered shank.

taper bit

A long cone-shaped noncoring bit used in drilling blastholes and in wedging and reaming operations. When the nose of the bit is rounded and the overall shape resembles the silk end of a corncob, the bit often is called a corncob bit. CF: bullnose bit.

tapered core bit

A core bit having a conical diamond-inset crown surface tapering from a borehole size at the bit face to the next larger borehole size at its upper, shank, or reaming-shell end, as from EX to AX, or BX to NX.

tapered end

An end of rope having a reduced diameter to facilitate threading the rope through fittings and over pulleys.

tapered-flange beam

The common form of rolled steel joist in which the inner surfaces of the flanges are tapered, normally at an angle of 98 degrees to the web. See also: web.

tapered reamer

A reamer having a conical diamond-inset surface tapering from any borehole size at its lower (bit) end to the next larger borehole size at its upper (core barrel) end, such as EX to AX, AX to BX, BX to NX.

tapered step-core bit

See: tapered step-face bit.

tapered step-face bit

A tapered core bit having the cutting face set in the same manner as a step-face bit.

tapered tap

See: tap.

taper-lock sprocket

A sprocket with a split tapered bushing for rigid mounting on a shaft.

taper of thread

Measurement in inches of taper or slope for a 1-ft (0.3-m) length of the threaded section of rod or pipe.

taper pin

A straight-sided pin that is smaller at one end than at the other.

taper rope

A rope that has a gradually diminishing diameter from the upper to the lower end. The diameter of the rope is decreased by dropping one wire at a time at regular intervals. Both round and flat ropes may be made tapered, and such ropes are intended for deep shaft hoisting with a view to proportioning the diameter of the rope to the load to be sustained at different depths.

taper-type dropper

A device by which straight-type wedge can be attached to a diamond-drill rod, lowered, and set in a borehole.

tape-triangulation method

A method of measuring mine roadway area in which a tape is stretched diagonally across the roadway. Offsets to the roof, floor, and sides are taken at right angles to the tape and on both sides of it. Alternatively, the floor of the cross section is divided into equal increments and vertical offsets to the roof are made at each division. Horizontal offsets to the sidewalls are made from the nearest adjacent vertical offsets. The measurements so obtained are plotted to scale, and the area of the resulting diagram is determined from the plot. Syn: mine roadway area measurement.


A hole at or near the bottom of a furnace or ladle through which molten metal, matte, or slag can be tapped or drawn from a furnace. Also called tapping hole. Syn: metal notch.


The mineral series ferrotapiolite-manganotapiolite.


a. A sliding member working in a guide, interposed between a cam and the push rod or valve system that it operates, to eliminate side thrust on the latter.

b. The collar under which a cam is inserted so as to lift a stamp. Also called disk.


a. Opening the outlet of a melting furnace to remove molten metal.

b. Removing molten metal from a furnace. c. The act of boring a hole into old workings to release gradually any accumulation of water and gas. This may be followed by driving an advance heading into the area. As the heading is extended, boreholes are kept in advance of the face to prevent the sudden breakthrough of water. See also: inrush of water.

tapping assembly

A mechanical device consisting of a short piece of casing cemented in the collar of a borehole at the upper end of which is affixed a gate or large plug valve followed by a rod stuffing box. Utilizing this assembly, underground drilling can be accomplished safely in areas of high hydrostatic pressure.

tapping bar

See: tap bar.

tapping clay

A plastic clay used in plugging the tap-hole of a smelting furnace.

tapping old workings

Boring a hole into old workings to release gradually any accumulation of water and gas. The borehole tapping may be followed by driving an advance heading into the area. As the heading is extended, boreholes are kept in advance of the face to prevent the sudden breakthrough of water. See also: inundation; inrush of water.


a. A thick brown to black viscous organic liquid, free of water, which is obtained by condensing the volatile products of destructive distillation of coal, wood, oil, etc. It has a variable composition, depending on the temperature and material used to obtain it.

b. Any of various dark brown or black, bituminous, usually odorous, viscous liquids or semiliquids that are obtained by the destructive distillation of wood, coal, peat, shale, and other organic material, and yield pitch on distillation. c. Soft pitch or thickened petroleum, found in cavities of some limestones.


An orthorhombic mineral, Ba (sub 4) Fe (sub 4) (B (sub 2) Si (sub 8) O (sub 27) )O (sub 2) Cl ; forms a series with titantaramellite; forms reddish-brown radiating fibrous aggregates; at Candoglia, Piemont, Italy.


A monoclinic mineral, Na (sub 2) CaFe (sub 3) Al (sub 2) (Si (sub 6) Al (sub 2) )O (sub 22) (OH) (sub 2) ; amphibole group with magnesium replacing iron toward magnesiotaramite; black; at Wali-tarama, Mariupol, Ukraine.


An orthorhombic mineral, K (sub 2) CrO (sub 4) ; has the olivine structure; yellow.


An interstratified mica and clay.


A triclinic mineral, Zn (sub 2) (PO (sub 4) )(OH) ; forms a series with paradamite; at Broken Hill, Kabwe, Zambia. Syn: salmoite.


a. To weigh mine cars when empty in order to determine the weight of coal in a car when the loaded car is weighed, done at specific intervals so that miners paid on a tonnage basis may receive proper credit for coal that they have loaded.

b. Allowance for weight of packing or container in which goods are moved. The difference between gross and net weight.


a. Sliding weight on a leveling rod used in surveying, to enable the staffman to read the line of collimation. In underground leveling, a bead on a hanging plumbline used for the same purpose; distance from this to the roof or working is then measured.

b. The point a borehole or exploration work is intended to reach. c. The distinctive marking or instrumentation of a ground point to aid in its identification on an aerial photograph. It is a material marking so arranged and placed on the ground as to form a distinctive pattern over a geodetic or other control-point marker, on a property corner or line, or at the position of an identifying point above an underground facility or feature. d. The image pattern on an aerial photograph of the actual mark or target placed on the ground prior to photography. e. The vane or sliding sight on a surveyor's level rod; a device, object, or point upon which sights are made.

target rod

A type of leveling staff provided with a sliding target, which can be moved by the staffman, under direction from the leveler, to a position in which it is in line with the line of sight of the level, the staff reading being recorded by the staffman.


Asphalt that is made artificially from grit, crushed stone, or gravel and is bonded or coated with tar or a tarbitumen mixture. See also: premix.


A thin alteration film that forms on mineral surfaces, esp. on copper minerals, with color and luster different from that on fresh fractures.

Tarnowitz process

A metallurgical process in which large charges of lead ore are roasted at low temperatures in furnaces and treated substantially, such as in the Carinthian process. The residual containing considerable lead is remelted in special furnaces.


a. The coating of piles used for permanent work with prepared acid-free tar before driving. The tar is obtained from the high-temperature carbonization of coal in horizontal retorts.

b. The act of coating, (as of a pipe) with tar.


The number of tons or the amount of ore or material that can or should be loaded either by mechanical loaders or by hand loaders. Also called score.

task training

Specific training given to a miner prior to performing a task where the worker has had no previous work experience. CF: new miner training; refresher training.

Tasmanian alexandrite

Alexandrite (chrysoberyl) of good gem quality from Tasmania, Australia.


An impure coal, transitional between cannel coal and oil shale. Syn: combustible shale; yellow coal; Mersey yellow coal; white coal.

tasmanite shale

See: tasmanite.


An orthorhombic mineral, Ca (sub 6) Mg (sub 2) (SO (sub 4) ) (sub 2) (CO (sub 3) ) (sub 2) Cl (sub 4) (OH) (sub 4) .7H (sub 2) O ; with anhydrite in saline strata of the Caspian depression.

tator butt

Shrop. Fragile sandstone.

tautline cableway

The tautline cableway differs from the aerial tramway in that its operation is limited to the distance between two towers (not more than 3,000 ft or 915 m apart), it has only one carrier, and the traction cable is reeved at the carrier so that loads can be raised and lowered. Also, the tautline cableway is not restricted to a fixed position; the towers can be mounted on trucks or crawlers, and the machine then can be shifted across a wide area. The machine will hoist loads from any point under the span, convey these loads in either direction, and lower these loads at any point under the span. By using movable towers, an area of any length can be traversed. Equipped with slings, this machine will pick up and carry unwieldy loads of every kind; then by exchanging the slings for a skip, it will handle large chunks of ore, stone, etc., or it can be equipped with a dump bucket to handle any bulk material, including semifluid mixtures.


Descriptive term for amphoteric substance, able to react in accordance with two oppositely directed structural arrangements of its atoms.


An old name for an apatite mineral.


A triclinic mineral, LiFe(PO (sub 4) )(OH) ; amblygonite group; forms green or yellow fine-grained aggregates; in Brazil.


A yellow to green to dark-green variety of epidote containing chromium; occurs in Tawmaw, upper Burma (Myanmar).


Serpentine from Chester County, PA.


a. An obsolete name for bentonite; named after William Taylor who made the first commercial shipments of the clay from the Rock Creek district, Wyoming.

b. A variety of arcanite containing ammonium found in guano beds on islands off Peru.

Taylor producer

A furnace used for the manufacture of producer gas.

Taylor-White process

A process for heat-treating high-speed steels.


A bolt with a T-shaped head, made to fit into a T-shaped slot in a drill swivel head; by means of it the swivel head can be turned to any angle of inclination to drill a borehole. Also, a similar bolt made to fit into a T-slot in the bed of a machine, for the purpose of holding a piece of metal to be machined or to fasten a machine to its base.

tchesa stick

a. An igniting stick used to light powder fuses when firing a round of shots. Also called a fire stick.

b. A paper shell about 1/4 in (0.64 cm) in diameter and 8 in (20.3 cm) long, filled with a balanced combustible that gives a strong spitting flame of 4 min duration. This device requires the individual lighting of each fuse. c. See: fuse lighter.


A boring tool with its cut-edge made in the form of the letter T.


An orthorhombic mineral, (Pb,Sn)S ; perfect basal cleavage; soft; blackish gray; sp gr, 6.4; in veins; a source of lead and tin.

teardrop set

A surface-set damond-bit crown molded in a die, prepared so that each inset diamond is backed by a raised teardrop-shaped mound of matrix metal.

tear fault

A steep to vertical fault associated with a low-angle overthrust fault and occurring in the hanging wall. It strikes perpendicular to the strike of the overthrust; displacement may be horizontal, and there may be a scissor effect. It is considered by some to be a type of strike-slip fault.

teary ground

a. Ground easily broken and worked.

b. Corn. A lode or stratum that breaks easily by reason of many joint planes.

teasing rods

Light iron rods, about 2 ft (0.6 m) long, hinged together to form one continuous length of 40 to 60 ft (12 to 18 m). They are pushed up inside a drainage borehole casing to clear stoppages of pebbles and gravel, thus allowing the drainage water to flow freely.

teaze hole

The opening of a glass furnace through which fuel is introduced.


a. A long, relatively narrow unit of downfolding of sialic crust considered to be related to mountain-building processes.

b. The downfolded portion of an orogen. Syn: downbuckle.


See: orogeny.


Said of or pertaining to the forces involved in, or the resulting structures or features of, tectonics. Syn: geotectonic.

tectonic breccia

A breccia formed as a result of crustal movements, usually developed from brittle rocks. CF: fault breccia; fold breccia; crush breccia.

tectonic conglomerate

See: crush conglomerate.

tectonic gap

See: lag fault.

tectonic map

A map that portrays the architecture of the outer part of the Earth. It is similar to a structure-contour map, which primarily shows dipping strata, folds, faults, and the like, but the tectonic map also presents some indication of the ages and kinds of rocks from which the structures were made, as well as their historical development.


A branch of geology dealing with the broad architecture of the outer part of the Earth; i.e., the regional assembling of structural or deformational features, a study of their mutual relations, origin, and historical evolution. It is closely related to structural geology, with which the distinctions are blurred, but tectonics generally deals with larger features. Adj: tectonic. Syn: geotectonics.


See: diastrophism.


Any rock whose fabric reflects the history of its deformation; a rock whose fabric clearly displays coordinated geometric features that indicate continuous solid flow during formation (Turner and Weiss, 1963). Also spelled tektonite.


A radar apparatus that detects changes in rock structure, particularly faults.


One who studies clastic deformation, flow, and rupture of constituent materials of the Earth's crust and mantle to make deductions concerning the forces causing these deformations (changes).


The outer part of the Earth above the level of isostatic equilibrium, in which the dynamic processes are thought to occur that cause orogenesis near and at the surface. CF: crust.


In founding, an ingate in a mold.


a. Eng. A crossvein meeting a main vein without intersecting it.

b. A sleeve with a third opening in the side, usually at right angles, to allow a branch line to be connected to the main pipeline. c. A fitting, either cast or wrought, that has one side outlet at right angles to the run. A single outlet branch pipe.


A rolled steel section in the shape of the letter T, the flat top being the table.


See: T-bolt.


To pour molten metal from a ladle into ingot molds. The term applies particularly to the specific operation of pouring either iron or steel into ingot molds. Also called teeming.


a. A pourer of metal.

b. One who controls the rate of pouring (teeming) stainless steel into molds. c. The person who teems or casts the pot of glass. See also: casting.


a. Shaping glass by pouring it into or on molds, tables, or rolls.

b. See: casting.

teeming trough

Lanc. A cistern (or trough) into which the water is pumped from a mine.


a. A tetragonal mineral, Na (sub 2) B(OH) (sub 4) Cl .

b. See: burkeite; gauslinite. From Borax Lake, CA.


a. Dancing or boiling movement of small particles in a rising fluid column, when the velocity is too high to let them fall and too low to sweep them clear. Characteristic zone in hydraulic classifiers.

b. The condition of a suspension of solids in an upward-moving current of water or air, whereby the support given to the particles reduces the internal friction between them to such an extent that the suspension acquires fluid or partially fluid properties.


An orthorhombic mineral, CuTeO (sub 3) .2H (sub 2) O ; blue; at the Teine Mine, Japan.


Fossil hydrocarbon similar to fichtelite.


Glass spheroid, often with aerodynamic shape, found in strewn fields and associated with impact craters; each cluster of tektites is named for its locality, such as moldavites and australites. A tektite has been shaped by flight through the atmosphere while chilling and ablating and melted by meteorite impact. See also: water chrysolite.


See: tectonite.


a. Anglicized from the German telit. Greater fragments of plant tissues, which are completely soaked with vitrain; i.e., the cell walls as well as the cell cavities.

b. Used in the names of transitional coal lithotypes, e.g., clarotelain.


A vertical rectangular timber or steel chute for the transfer of coal to a lower level. Strips of wood placed crosswise in the chute retard the downward flow, and the chute is kept full for the same purpose.


Said of a hydrothermal mineral deposit located far from its magmatic source. CF: apomagmatic; cryptomagmatic. See also: telethermal.

telemeter rod

A leveling staff used in connection with stadia work. See also: stadia rod.


The remote manual operation of equipment that is usually not within the direct eyesight of the operator, yet the operator requires and is provided with sensory information (sight, sound, accelerations, etc.) for effective manual control.

telephoto lens

A combination of positive and negative lenses designed to obtain larger magnification of distant objects than is possible with ordinary lenses.

telescopic derrick

A drill derrick divided into two or more sections, made so that the uppermost sections nest successively into the lower sections. In use, the sections are extended and locked into place to form a tall derrick and when moved are nested to form a unit length transportable on a single truck.

telescopic drill rig

A mobile electric, hydraulic, four-drill rig for boring blasting holes in quarries and opencast pits. All drills, percussive and rotary, can be simultaneously or independently raised, lowered, or slewed, enabling the rig to serve a working face 32 ft (9.8 m) high and 24 ft (7.3 m) wide.

telescopic loading trough

A shaker conveyor trough of two sections, one nested in the other, used near the face for advancing the trough line without the necessity of adding either a standard or a short length of pan after each cut. C-clamps hold the two sections together in any desired length.

telescopic section

That section of a rigid side-framed conveyor that is (1) adjustable in length, (2) immediately adjacent to the tail section, and (3) so designed that it forms a continuous framing and cover for the return belt when the tail section is pulled back to tension the belt.

telescoping conveyor

A type of conveyor, the length of which may be varied by telescoping frame members. See also: extendable conveyor.


Said of a hydrothermal mineral deposit formed at shallow depth and relatively low temperatures, with little or no wall-rock alteration, presumably far from the source of hydrothermal solutions. Also, said of that environment. See also: telemagmatic. CF: hypothermal deposit; mesothermal; epithermal; xenothermal; leptothermal.


a. This term was proposed by W.J. Jongmans (1935) to designate a vitrinite showing cellular structure. The Nomenclature Subcommittee of the International Committee for Coal Petrology decided in 1957 to use the term telinite only for the cell walls seen in vitrinite. Only in this manner can telinite be rightly included among the macerals. Telinite shows more or less clearly defined cell structure (wood, periderm, etc.) sometimes deformed. The cells are generally filled with collinite, but the structure is better shown when the cells are either empty or filled by material such as resinite, fine micrinite, clay minerals, etc.

b. A maceral of coal within the vitrinite group, characteristic of vitrain and consisting of cell-wall material. CF: suberinite; xylinite.


See: tab.


a. A simple device for indicating selected conditions of loading, flow, direction, etc.

b. A device for keeping a check on employees (as factory hands, drivers, check takers), esp. a time clock.

telluric bismuth

A former name for tetradymite. See also: tetradymite.

telluric current

Natural electric current that flows on or near the Earth's surface in large sheets. Syn: earth current.

telluric-current prospecting

A geophysical prospecting technique utilizing natural Earth currents as a source instead of artificially generated currents injected into the ground.

telluric ocher

The mineral tellurite, TeO (sub 2) .

telluric silver

See: hessite.


A mineral that is a compound of a metal and tellurium, such as hessite, Ag (sub 2) Te .


Ores of the precious metals (chiefly gold) containing tellurium.


Yielding or containing tellurium.


An orthorhombic mineral, TeO (sub 2) ; dimorphous with paratellurite; colorless to yellow; occurs in hydrothermal veins.


A trigonal mineral, Te , native tellurium; soft; sp gr, 6.2; (super ) semimetallic; in pyrite, sulfur, or in the fine dust of gold-telluride mines.

tellurium glance

See: nagyagite.

tellurium mineral

Primarily native tellurium, Te ; tellurite, TeO (sub 2) ; tetradymite, Bi (sub 2) Te (sub 2) S ; or hessite, Ag (sub 2) Te .


See: melonite.


A trigonal mineral, Bi (sub 2) Te (sub 3) ; tetradymite group; forms a series with tellurantimony.


Trade name of a rugged portable electronic device that measures ground distances precisely by determining the velocity of a phase-modulated, continuous, microwave radio signal transmitted between two instruments operating alternately as master station and remote station. It has a range up to 35 to 40 miles (56 to 64 km). CF: geodimeter.


An electric hoist that hangs from a power-driven wheeled cab rolling on an overhead rail; it is often referred to as a monorail. See also: aerial ropeway.


Automatic aerial transportation, as by the aid of electricity, esp. that system in which the carriages having independent motors are run on a stout wire conducting an electric current.

Telsmith breaker

A type of gyratory crusher often used for primary crushing. It has a fixed spindle; i.e., the spindle is not suspended from above, but is mounted in a long eccentric sleeve. Rotation of the sleeve imparts a gyratory motion to the crushing head, but gives a parallel stroke; i.e., the axis of the spindle describes a cylinder rather than a cone as in the suspended spindle gyratory. Adjustment for set in the Telsmith breaker is accomplished by placing shims between the bottom of the breaking head and an adjusting plate--the addition of shims at this point raises the crushing head and increases the throat opening.

Telsmith gyrasphere

A type of secondary crusher that utilizes the gyratory principle; it has a hemispherical crushing head.


See: earthquake.


See: maucherite.


a. The heat content of a body as measured on a definite scale based on some observable phenomenon; e.g., the expansion of mercury on heating. See also: absolute temperature; Celsius; centigrade; critical temperature; Fahrenheit; Kelvin temperature scale; Rankine scale.

b. A degree of hotness or of coldness measured on one of several arbitrary scales based on some observable phenomenon; e.g., the expansion of mercury on heating. The degree of a material substance that is a linear function of the kinetic energy of the random motion of its molecules. The degree of a vacuum that depends upon the density of the radiant energy within it. Abbreviations and symbols, temp; T; t; T; t. CF: absolute zero.

temperature coefficient

A numerical value indicating the relation between a change in temperature and a simultaneous change in some other property (e.g., solubility). Specif., the factor a in the equation R (sub t) = R (sub 0) (1 at), in which R (sub t) equals the resistance of a conductor at t degrees C, and R (sub 0) equals its resistance at 0 degrees C. Syn: positive temperature coefficient.

temperature colors

Colors shown to the eye by incandescent bodies at different temperatures.

temperature dew point

Temperature at which condensation of water occurs; a saturation temperature.

temperature gradient

a. The rate of change of temperature with distance in a specified direction. Also called lapse rate.

b. A curve showing the temperature at different distances from the hot face, in a refractory wall.

temperature logging

The measurement of temperature in boreholes by use of a delicate thermometer that will record temperature anomalies of as much as 7 degrees F (3.9 degrees C) for thin coal seams in coal measures according to the thermal conductivity of the rocks concerned.

temperature profile recorder

A portable unit consisting of a thermistor sensing element, 6-V power supply, amplifier, and recorder. The recorder is geared to a drum containing an electrical cable to which the bead is fastened. When the bead is lowered into the water, the paper on the recorder is moved accordingly. Depth is measured by the amount of wire paid out. This device is used in shallow water, particularly in lakes.

temperature-regulating equipment

Any equipment used for heating and cooling the rectifier together with the devices for controlling and indicating its temperature.

temperature standards

For normal measurement, 0 degrees C (regarding gas properties). For thermodynamics and physical properties, either 18 degrees C or 25 degrees C, as defined in each stated case.

temperature steel

Reinforcement introduced into a concrete slab or other member to minimize any cracks arising from shrinkage or from temperature stresses.

temperature stress

Stress in a structural member due to a rise or fall of temperature. See also: temperature steel.

temperature survey

a. A geophysical prospecting method that measures either (1) temperature anomalies in boreholes or (2) temperature trends and concentrations along the ground surface. For example, a temperature survey across a salt dome may give peak values in the central area, due to the high thermal conductivity of the buried salt mass. See also: temperature logging.

b. Measurement of temperature in drill holes. An absolute accuracy of about 0.05 degrees C and a precision of about 0.005 degrees C can be obtained. Maps of isotherm surfaces can be constructed that help to detect anomalies in geologic structure or subsurface ground-water conditions.


In brickmaking, (1) moistened and worked to the proper consistency, as clay for bricks or molding, and (2) capable of being cut with ease, as bricks made of such clay.

tempered steel

Steel that has been hardened and subsequently tempered by a second lower heating.


One who or that which tempers; specif., a machine for mingling and thoroughly working potter's clay, brick clay, mortar, plaster, or other materials.

temper hardening

A term applied to alloys that increase in hardness when heated after rapid cooling; also to the operation of producing this. Also called artificial aging; distinguished from aging or age hardening, which occurs at atmospheric temperature. Both processes are covered by the term precipitation hardening.

tempering bar

See: furgen.

tempering furnace

A furnace for heating articles in the process of tempering.

tempering machine

A machine for giving large steel plates a uniform and thorough tempering without permitting them to bend or buckle; usually by pressing them between hot masses of iron, or by firmly clamping them between jaws or plates while immersing them in a tempering bath.

tempering oven

An oven for heating glass in the process of annealing; a leer.


a. A form for building tunnel inverts.

b. A pattern device used as a guide to mark points at which boreholes are to be collared in ring drilling.

temporary adjustment

An adjustment, such as leveling or focusing, made to a surveying instrument at each setup. See also: permanent adjustment.

temporary hardness

See: carbonate hardness.

temporary hardness of water

The carbonate component of water hardness, which can be destroyed by boiling. See also: hard water.

temporary roof support

In coal mining; during roof bolting process, vertical posts are installed tight with wedges near the area where the next roof bolt will be installed. These are installed by reaching from a bolted area of the roof. Installed to support potentially loose roof to prevent fall onto persons.

temporary shaft support

A timber or steel lining inserted for a limited period until a permanent shaft support is installed. See also: skeleton tubbing.

temporary splice

According to the Federal Coal Mine Safety Act, a temporary splice is one that does not have a rubber or neoprene jacket vulcanized over the splice and bonded to the cable jacket.