Monthly, perhaps, miners getting large bottle (6)
I believe the answer is:
magnum
'large bottle' is the definition.
(large wine bottle)
'monthly perhaps miners getting' is the wordplay.
'monthly perhaps' becomes 'mag' (a monthly magazine).
'miners' becomes 'NUM' (National Union of Mineworkers).
'getting' means one lot of letters go next to another.
'mag'+'num'='MAGNUM'
(Other definitions for magnum that I've seen before include "Two champers bottles in one" , "1 1/2 litre champagne bottle" , "Two wine bottles in one" , "that may be full of slugs" , "Just one bottle of champagne?" .)