If you've noticed that i put crystals along the walls of the mine, then u should recognize that there are more crystals/ores on my last one... i figured the miners and foremen needed a little more so the went deep into the mine (my next drawing im going to put up within the next day), saw Heodr, and were eventually killed. 

I thought that could be the reasoning for why the miners went deep into the mine in the first place...