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GLOSSARY OF

Mothergate .—The principal avenue, used asa road from the shafts to the workings and ex-tremities of the mine.

Overman.—A kind of underviewer, who hascommand of all the mine below. Mr. Buddieobserves, “ that the office of overman is ofthe utmost importance to the management ofa coal mine.” I admit it is so j but what isthe use of this office if the person filling it bepermitted to leave the duties to some of thehewers or sinkers; need I name an instancewhere the overman seldom descends a mine ?

Onsetters are those who hook and unhookthe corves at the bottom of a shaft.

Pillars .—The coal left between the boardsand headways for the support of the roof, andwhich is generally in the shape of a parallel-ogram. The quantity left for this purpose de-.pends upon the depth of the mine, and thethill or floor, and roof, which if soft, requiremore to be left; the general average is fromone-fourth to one-sixth of the stratum for pil-Jars; the Walls-end coals are so valuable, thatMr. Russel* is taking away all the coals, andsubstituting stone walls.

Pot-holes (Staffordshire).—Holes in the roofof a mine, occasioned by the falling in of thestrata in which gas accumulates.

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