Answer:

adit

AnswerCrossword Clue
ADITMine entrance
ADITShaft entrance
ADITColliery access
ADITMine opening
ADITPassage to get 8-Down
ADITMiner's entry
ADITAccess for a collier
ADITMine passage
ADITMine access
ADITShaft's end
ADITCollier's entrance
ADITPit passage