The reverse of material extracted from the earth (5)
I believe the answer is:
mined
'extracted from the earth' is the definition.
I can't tell whether this definition defines the answer.
'the reverse of material' is the wordplay.
'the reverse of' is a reversal indicator.
'material' becomes 'denim' (type of fabric).
'denim' backwards is 'MINED'.
Can you help me to learn more?
(Other definitions for mined that I've seen before include "proceeded secretly" , "Sought diamonds?" , "laid eggs" , "Excavated as for coal or diamonds" , "Dug from pit" .)