Owns openings around top of mine (6)
I believe the answer is:
admits
'owns' is the definition.
(I've seen this before)
'openings around top of mine' is the wordplay.
'openings' becomes 'adits'.
'around' is an insertion indicator.
'top of' indicates taking the first letters.
The first letter of 'mine' is 'm'.
'adits' placed around 'm' is 'ADMITS'.
(Other definitions for admits that I've seen before include "Owns up or lets in" , "Concedes" , "Allows in or accepts guilt" , "Does not deny" , "Takes in" .)