Inscription from mine covered in messy heap (7)
I believe the answer is:
epitaph
'inscription' is the definition.
(I know that epitaph is a type of inscription)
'mine covered in messy heap' is the wordplay.
'mine' becomes 'pit' (down the pit).
'covered in' means one lot of letters goes inside another.
'messy' indicates an anagram.
'heap' is an anagram of 'eaph'.
'pit' going inside 'eaph' is 'EPITAPH'.
'from' is the link.
(Other definitions for epitaph that I've seen before include "Gravestone message" , "final comment" , "message celebrating memories?" , "Grave words" , "last words" .)