Work with miners cutting top of oak tree (8)
I believe the answer is:
laburnum
'tree' is the definition.
(type of European tree)
'work with miners' is the wordplay.
'work with' becomes 'labur' (I am not sure about this - if you are sure you should believe this answer much more).
'miners' becomes 'num'.
'labur'+'num'='LABURNUM'
'cutting top of oak' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
(Other definitions for laburnum that I've seen before include "Shrub known as golden chain" , "Poisonous shrub with yellow flowers" , "Tree with yellow flowers and poisonous seeds" , "Album run for the yellow tree" , "Tree or shrub with bright yellow flowers" .)