Illustrated Mining Terms


Cage - In a mine shaft, the device, similar to an elevator car, that is used for hoisting personnel and materials.

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Calorific value - The quantity of heat that can be liberated from one pound of coal or oil measured in BTU's.  
Canopy - A protective covering of a cab on a mining machine.

Cap - A miner's safety helmet. Also, a highly sensitive, encapsulated explosive that is used to detonate larger but less sensitive explosives.

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Car - A railway wagon, especially any of the wagons adapted to carrying coal, ore, and waste underground.

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Car-dump - The mechanism for unloading a loaded car.   

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Carbide bit - More correctly, cemented tungsten carbide. A cutting or drilling bit for rock or coal, made by fusing an insert of molded tungsten carbide to the cutting edge of a steel bit shank.

Carbon-in-leach: a recovery process in which a slurry of gold ore, carbon granules and cyanide are mixed together. The cyanide dissolves the gold content and the gold is adsorbed on the carbon. The carbon is subsequently separated from the slurry for further gold removal.

Carbon-in-pulp: similar to carbon-in-leach process, but initially the slurry is subjected to cyanide leaching in separate tanks followed by carbon-in-pulp. Carbon-in-pulp is a sequential process whereas carbon-in-leach is a simultaneous process.

Cast - A directed throw; in strip-mining, the overburden is cast from the coal to the previously mined area.

Cave-in - the partial or complete collapse of a mine working.  
Caving System - stoping systems designed to take advantage of the natural tendency of some ores to cave.  
Certified - Describes a person who has passed an examination to do a required job.  
Chain conveyor - A conveyor on which the material is moved along solid pans (troughs) by the action of scraper crossbars attached to powered chains.

Chain pillar - The pillar of coal left to protect the gangway or entry and the parallel airways.  
Change house - A special building constructed at a mine where the miners changes to his working clothes.  
Chock - Large hydraulic jacks used to support roof in longwall and shortwall mining systems.

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Chute - An inclined opening, usually constructed of timber and equipped with a gate, through which ore is drawn from a stope into mine cars.

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Claim - A portion of mining land, usually 40 acres in size.

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Coal - A solid, brittle, more or less distinctly stratified combustible carbonaceous rock, formed by partial to complete decomposition of vegetation; varies in color from dark brown to black; not fusible without decomposition and very insoluble

Coal Gasification – The conversion of coal into a gaseous fuel.  

Fluidized Bed Coal Gasification Pilot Plant

Coal washing – The process of separating undesirable materials from coal based on differences in densities. Pyritic sulfur, or sulfur combined with iron, is heavier and sinks in water; coal is lighter and floats.

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Coke – A hard, dry carbon substance produced by heating coal to a very high temperature in the absence of air.
Collar - The term applied to the timbering or concrete around the mouth or top of a shaft. The beginning point of a shaft or drill hole at the surface.

Shaft Collar, Pacific Colliery

Colliery - British name for coal mine.

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Column flotation – A precombustion coal cleaning technology in which coal particles attach to air bubbles rising in a vertical column. The coal is then removed at the top of the column.

Small Test Cell

Comminution - The breaking, crushing, or grinding of coal, ore, or rock

Impact Mill. Used for primary and secondary comminution of soft to extremely hard materials.

Competent rock - Rock which, because of its physical and geological characteristics, is capable of sustaining openings without any structural support except pillars and walls left during mining (stalls, light props, and roof bolts are not considered structural support).  
Concentrate: a powdery product containing the valuable ore mineral from which most of the waste material has been eliminated.


Concentrator - A particular type of milling plant that produces a concentrate of the valuable minerals or metals.

Contact - The place or surface where two different kinds of rocks meet. Applies to sedimentary rocks, as the contact between a limestone and a sandstone, for example, and to metamorphic rocks; and it is especially applicable between igneous intrusions and their walls.

geologic contact

Continuous miner - A machine that constantly extracts coal while it loads it. This is to be distinguished from a conventional, or cyclic, unit which must stop the extraction process in order for loading to commence

Fox Continuous Miner

Contour - An imaginary line that connects all points on a surface having the same elevation.

Conventional miningThe first fully-mechanized underground mining method involving the insertion of explosives in a coal seam, the blasting of the seam, and the removal of the coal onto a conveyor or shuttle car by a loading machine.  
Conveyor - An apparatus for moving material from one point to another in a continuous fashion. This is accomplished with an endless (that is, looped) procession of hooks, buckets, wide rubber belt, etc.

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Convertor - A furnace that is used to reduce metal from a matte.

Bessemer Convertor

Core sampleA cylinder sample generally 1-5" in diameter drilled out of an area to determine the geologic and chemical analysis of the overburden and ore.

Counterweight - A dead or non-working weight attached to one end of a machine to balance the load carried on the opposite end.

Lower part with counterweight

Country rock - A term used to describe the general mass of rock adjacent to an orebody.  
Cover - The overburden of any deposit.             

Overburden dumps at Benguérir.

Creep - The forcing of pillars into soft bottom by the weight of a strong roof. In surface mining, a very slow movement of slopes downhill.

Crib - A roof support of prop timbers or ties, laid in alternate cross-layers, log-cabin style. It may or may not be filled with debris. Also may be called a chock or cog.

Cribbing - The construction of cribs or timbers laid at right angles to each other, sometimes filled with earth, as a roof support or as a support for machinery.

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Crossbar - The horizontal member of a roof timber set supported by props located either on roadways or at the face.  
Crosscut - A passageway driven between the entry and its parallel air course or air courses for ventilation purposes. Also, a tunnel driven from one seam to another through or across the intervening measures; sometimes called "crosscut tunnel", or "breakthrough". In vein mining, an entry perpendicular to the vein.


Cross entry - An entry running at an angle with the main entry.

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Crusher - A machine for crushing rock or other materials. Among the various types of crushers are the ball mill, gyratory crusher, Handsel mill, hammer mill, jaw crusher, rod mill, rolls, stamp mill, and tube mill.


Cut-and-fill: a method of underground mining in which ore is removed in slices or lifts, and then the excavation is filled with rock or other waste material (backfill) before the subsequent slice is mined. cutf1.gif (19894 bytes)
Cut-off grade - lowest grade of ore in a deposit that will recover mining costs; the cut-off grade determines the workable tonnage of an ore  
Cutter; Cutting machine - A machine, usually used in coal, that will cut a 10- to 15-cm slot. The slot allows room for expansion of the broken coal. Also applies to the man who operates the machine and to workers engaged in the cutting of coal by prick or drill.

Cyanidation: a method of extracting gold or silver by dissolving it in a weak solution of sodium cyanide.

Photo-Multistage CIL Pilot Plant

Cycle mining - A system of mining in more than one working place at a time, that is, a miner takes a lift from the face and moves to another face while permanent roof support is established in the previous working face.  

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