What regulations? Please be specific.
Oh and I'll give you one freebie: OSHA Laws that protect the health and lives of miners made coal significantly more expensive. We could always return to hearing about mine accidents every two months with tens to hundreds of dead miners if you wanted to make coal YUGE again. Operating costs went way up when mining companies suddenly had to view their miners as more than disposable bodies.
Second freebie: While cuckservatives and Trumpkins like to blame Obama for the increase in coal "cost", they can't ever seem to answer why. Probably because the only thing Obama did was end some coal subsidies, which were only making coal appear to be cheaper. In the end, you were still paying full price with your tax dollars.
So now that you got those two freebies, tell me what regulations specifically make coal more expensive.