>>404239Coal mines are full of poisonous and explosive gases that leech out of the coal. However poison gases and low O2 environments can exist inside hard rock mines. Furthermore the tunnels are weaker than hard rock mines. Hard rock mines are cut through hard rock. Around my neck of the woods it is mostly granite with arsenopyrite veins chased through the rock and mined out. Makes for some crappy acidic arsenic mud when the water runs through it but I guess it is full of gold, silver, and copper. Or at least it was at some point. Anyways I feel a lot safer inside one of those solid granite tunnels then, say, the talc mine I found the other day. When you can saw pieces off the wall with your pocket knife you probably shouldn't go in! Some poor bastards had to work that death trap....but yeah back to the point, mines are dangerous places in general, hard rock just less so. Less chance of a cave in, less chance of toxic atmospheres, and they aren't normally a tunnel through an ignitable fuel source....but I'm in WA so no matter what I'm in I will be screwed if an earthquake hits haha.
