goaf
採空區; 不含礦的巖石
Gove n. [Also goaf, goof, goff.] A mow; a rick for hay. [Obs.]
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Goaf n.; pl. Goafs or Goaves Mining That part of a mine from which the mineral has been partially or wholly removed; the waste left in old workings; -- called also gob .
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.
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