If you'll do illegal mining, ofcourse yes it's gonna cost you less than bitcoin mining but if you'll do a legal gold mining and follow all the rules and regulation and apply to respective government agencies and follow safety hush hush then believe me you will absolutely know why gold is very expensive. I know coz I do researched on Gold mining here in the Philippines .
As for Bitcoin mining, well I think it depend on what country you're in and cost of electricity on that country and ofcourse there's already solar energy so you have option.