"Once you start mining you will start noticing that the Drill gets hotter whenever you drill on a mine. You must pay attention to the "Heat" in your chatbox because if your drill reaches a Heat of 100 the drill will break and you will have to create another drill whispering "make" to "npc:mine".
It is recommended that you stop drilling when you reach a heat of 80-90 in order to make sure your drill does not break. It usually takes only a few seconds for the drill to cool down after you stop so you can begin drilling again soon after."
I quoted this from GM Haze from miner world update thread. I can't see the heat in my chatbox whenever i drill is there a command to toggle on?