Mining Glossary

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A

Abandoned Mine - Excavations, either caved or sealed, that are deserted and in which further mining is not intended.

Acid Mine Drainage - Liquid drainage from bituminous coal mines containing a high concentration of acidic sulfates, especially ferrous sulfate.

Adit - A horizontal opening giving access to a mine.

Advance Stripping - The removal of barren or sub-grade earthy or rock materials required to expose and permit the minable grade of ore to be mined.

Air Shaft - A shaft used wholly or mainly for ventilating mines, for bringing fresh air to places where men are working, or for exhausting used air.

Airway - Any underground gallery or passage through which a portion of the ventilation passes, that is, the air is carried. Sometimes referred to as an air course. Also called wind road.

Anode - The positive terminal of an electrolytic cell. Opposite of cathode.

Anthracite - A hard, black lustrous coal containing a high percentage of fixed carbon and a low percentage of volatile matter. Commonly referred to as hard coal. Anthracite ignites with difficulty, produces no smoke, burns at first with a very short blue flame that disappears after the coal is thoroughly ignited, and produces an intensely hot fire.

Ash - The inorganic residue remaining after ignition of combustible substances. In general, it differs in weight and composition from the original mineral matter.

Auger Mining - A mining method often used by strip-mine operators when the overburden gets too thick to be removed economically. Large-diameter, spaced holes are drilled up to 200 feet into the coal bed by an auger. Like a bit used for boring holes in wood, this consists of a cutting head with screw like extensions. As the auger turns, the head breaks the coal and the screw carries the coal back into the open and dumps it on an elevating conveyor; this, in turn, carries the coal to an overhead bin or loads it directly into a truck. Auger mining is relatively inexpensive, and it is reported to recover 60 to 65 percent of the coal in the part of the bed where it is used.