Prime explosives and mine cavity (6)
I believe the answer is:
armpit
'cavity' is the definition.
(I know that Armpit is a type of cavity)
'prime explosives and mine' is the wordplay.
I cannot quite understand how this works, but
'prime' could be 'arm' (I've seen this before) and 'arm' is present in the answer.
'mine' could be 'pit' (down the pit) and 'pit' is located in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for armpit that I've seen before include "(In anato my) the axilla" , "Hollow between limb and shoulder" , "part of the body" , "I'm rapt (anag)" , "Hairy spot" .)