Controlled ac is not bad if your profits are not hit because of it however one must be very careful here, most fire hazards happen because of ac and its damage, so if you have many alarms telling you how the room temperature is and have tools to stop if failures.

I'm against ac because the way I see is better be safe than sorry, although I'm not a miner, I believe there should be always a second route in case something goes wrong, so you can have exhaust fans but make a second air through in case even if the exhaust fan stops working, you trolls must be careful here, could burn the whole house because of this.