goaf

Noun

goaf (countable and uncountable, plural goafs or goaves)

1. A rick or stack (of hay, etc.) when laid up inside a barn (e.g., as winter fodder).
2. That part of a mine from which the mineral has been partially or wholly removed.
3. The waste left in old mine workings; goafing.
   • In an operation of this kind, primarily for the purpose of extracting the gas out of the goaves, but also with a view to drain the solid coal, it is clear that it is desirable, as much as possible, to draw as directly as possible from the goaf.1869, George Fowler, On a Method of Abstracting Explosive Gas from the Goaves of Coal Mines, in Transactions, Volume 18, North of England Institute of Mining Engineers, page 160
   • Hundreds of lives have been sacrificed by sudden outbursts of gas from the floor and goaf, and miners are constantly working in jeopardy, when a small expense would remove the gas, and prevent the casualties.1874, William Hopton, The Prevention of Catastrophes in Mines, in The Hermon Prize Essays: Essays on the Prevention of Explosions and Accidents in Coal Mines, W. M. Hutchings, page 57

   Synonyms:

   goave, goafing, gob, gobbin