Some colliers are buried (3)
I believe the answer is:
lie
'are buried' is the definition.
(to lie can mean to be buried)
'some colliers' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'LIE' is hidden within 'colliers'.
(Other definitions for lie that I've seen before include "Perjure" , "Tell untruths" , "Recline - untruth" , "Pork pie" , "Stretch out" .)