One looks for mine to do well without time in company (10)
I believe the answer is:
Here is my best explanation:
'one looks for mine' is the definition.
'do well without time in company' is the wordplay.
'do well' becomes 'prosper' (I've seen this before).
'without' indicates putting letters inside ('without' can be similar in meaning to 'outside').
'time' becomes 't'.
'in' is an insertion indicator.
'company' becomes 'co' (abbreviation).
't' going into 'co' is 'cto'.
'prosper' going around 'cto' is 'PROSPECTOR'.
'to' acts as a link.