Excavating (6)
I believe the answer is:
mining
'excavating' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for mining that I've seen before include "Excavating (ores)" , "Extracting ore etc. from the earth" , "Extracting ores or coal from the earth" , "non-renewable industry" , "Excavating (coal, ore)" .)