Underholing. See [Bearing in.]

Upcast. An opening from a mine through which air is taken out.

Vein. Used (improperly) synonymously with seam, bed, or stratum.

Wagon. A mine car.

Waste. Gob; coal dirt.

Water level. An entrance into or passage in a mine, driven with just sufficient grade to carry off water.

White damp. Carbonic oxide.

Wings. See [Keeps.]

Work. To mine.

Working face. A face at which mining is being done.