THE COMMENTATOR GLOSSARY OF
ANTHRACITE MINING TERMS

O - P - R

O

OPENING:
Surface entrance to mine workings.

OPERATOR:
The individual or company which operates a collier or collieries.

OUTBY:
In the direction of the mine opening.

OUTCROP:
That part of a stratum that comes to the surface.

OUTPUT:
The amount of coal put out from mine during a given time.

OVERBURDEN:
The strata and soil between a coal bed and the surface.

OVERCAST:
An air bridge.

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P

PACK WALL:
A wall or pillar built of gob to support the roof.

PANEL:
A group of working places separated from the other workings by large pillars.

PARTING:
A natural, usually smooth, separation between strata.

PERMISSIBLE:
A term applied to anything the use of which is permitted by the United States Bureau of Mines.

PICKER:
A person employed to separate refuse from coal by hand in a breaker.

PICKING TABLE:A platform on which coal is run to be picked free from slate.

PILLAR:
A solid block of coal between voids underground.

PILLAR ROBBING:
A systematic removal of coal pillars between chambers.

PINCH OUT:
1. Diminution of disappearance of a bed of coal. 2. A slight squeeze.

PITCH:
The rise or inclination of a seam.

PLACE:
The spot in a mine where a miner works.

PLANE:
A steep transportation road down which loaded cars are lowered.

PLOT:
To lay out on a map plans for future mining.

POCKET:
(a) A hopper from which coal is loaded into cars. (b) A local accumulation of gas.

POST:
To bring the survey and maps of a mine up to date.

POT HOLE:
An opening to the surface caused by subsidence, sometimes called cave hole.

PRIMER:
An explosive cartridge which contains the detonator by which the charge will be set off.

PROP:
A single timber set upright to support the roof.

PROVE:
To determine, by boring from the surface or driving a passageway underground, the location and character of a coal bed or the nature of rock strata.

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R

RECOVERY:
The percentage of the original seam that is mined.

REGULATOR:
A device for controlling the amount of air that flows past a given point.

RESERVES:
Solid blocks of coal left in the ground for support of the surface or other specific purpose.

RESPIRATOR:
A device which screens out inhaled dust.

RETREAT:
To mine out pillar coal in the direction of the mine opening.

RETURN:
A passageway along which exhaust air travels from the workings of the outside.

RIB:
The side of a working place.

RIDER:
A thin seam of coal overlying a thicker one.

ROB:
To mine out pillar coal in the direction of the mine opening.

ROCK TUNNEL:
A tunnel driven through rock, usually to connect two or more beds.

ROLL:
A high place in the bottom or a low place in the top of a mine passage.

ROLLS:
Toothed cylinders rotated toward each other to break up large chunks of coal.

ROOF:
The rock above a coal bed.

RUNAROUND:
A passage in the shaft pillar to enable men to pass safely from one side of the shaft to the other.

RUNNER:
A transportation employee who runs loaded mine cars by gravity.

RUN-OF-MINE:
The coal just as it is mined, less impurities.

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