Cartridge pin. A round stick of wood on which the paper tube for the cartridge is formed.

Cave-hole. A depression at the surface, caused by a fall of roof in the mine.

Chain pillars. Heavy pillars of coal, lining one or both sides of the gangway, and left for the protection of that passage.

Chamber. See [Breast.]

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

Choice damp. See [After-damp.]

Cleavage. The property of splitting on a certain plane.

Collar. The upper horizontal crosspiece uniting the legs in the timbering of a drift, tunnel, slope, or gangway.

Colliery. All the workings of one mine, both underground and at the surface.

Conglomerate. The rock strata lying next beneath the coal measures.