Break-through. A cross-heading or entrance, used in the bituminous mines.

[Breast.] The principal excavation in the mine from which coal is taken; known also as chamber.

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

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

Buggy. A small car or wagon used for transporting coal from the working face to the gangway.

Buntons. The timbers placed crosswise of a shaft down its entire depth, dividing it into vertical compartments.

Butt. In bituminous coal seams, the vertical planes of cleavage at right angles to the face cleavage.

Butty. A comrade; a fellow-worker in the same chamber.

Cage. See [Carriage.]

[Carriage.] The apparatus on which coal is hoisted in a shaft.