Economical extracting business, perhaps? (4,4)
I believe the answer is:
coal mine
'economical extracting' is the definition.
I can't judge whether this definition defines the answer.
'business perhaps?' is the wordplay.
I cannot really see how this works, but
'business' could be 'co' (short for company) and 'co' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for coal mine that I've seen before include "Pit" , "source of fuel" .)