Mine's topical preparation (7)

I believe the answer is:

coalpit

'mine's' is the definition.
(coalpit is a kind of mine)

'topical preparation' is the wordplay.
'preparation' is an anagram indicator.
'topical' anagrammed gives 'COALPIT'.

(Another definition for coalpit that I've seen is " mine".)

I've seen this clue in The Telegraph.

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