Coal and the coal mines

by Homer Greene

Double entry. One of the systems by which openings into the bituminous coal mines are made.

Downcast. The passage or way through which air is drawn into a mine.

Drift. A water-level entrance to a mine, driven in from the surface on the coal.

Drill. Any tool used for boring holes in the rock or coal.

Driving. Excavating any horizontal passage in or into the mines.

Drum. A revolving cylinder, at the head of any hoisting-way, on which the winding rope is coiled.

Egg coal. One of the regular sizes of prepared anthracite.

Entrance. See [Cross-heading.]

Entry. The main entrance and traveling road in bituminous mines.