2) Try and keep the room extra cool, perhaps put a fridge in the mining room with the door open
Refrigerators are not magical cold-making boxes, they're heat exchangers. Any heat they remove from their contents is expelled through the coils on the back of the fridge. Given that this is also less than 100% efficient, an open-doored refrigerator adds more heat to a room than it removes.
Honestly people, L2Physics
Also, the compressors are designed to run for about 5 minutes at a time, leaving the door open is a fast way to destroy a refrigerator