Stone; mine (3)
I believe the answer is:
pit
This clue is a double definition.
'stone' is the first definition.
(I know that stone can be written as pit)
'mine' is the second definition.
(as in a mining pit)
(Other definitions for pit that I've seen before include "Cherry stone" , "Mine; fruit stone" , "Mining hole" , "where orchestra plays" , "Mine-shaft" .)