Goaf

POS

Noun

top

CIDE DICTIONARY

Goaf, n. [Cf. 1st Gob.].

That part of a mine from which the mineral has been partially or wholly removed; the waste left in old workings; -- called also gob . [1913 Webster]

To work the goaf or To work the gob, to remove the pillars of mineral matter previously left to support the roof, and replace them with props. Ure.

For further exploring for "Goaf" in Webster Dictionary Online