Brilliant! put huge stores of oxygen in a coal mine. Nothing bad could happen here..........
Strip mine. Build golf courses after you fill the pit with Yankee garbage that they barge down.
I can just see it now...what happens to an Oxygen tank in a fire or explosion? Miners who would have survived would be killed in the (more intense) fire or hit with shrapnel. Oxygen tanks in an enclosed area with a risk of fire are not a good idea.
That could create quite a fire; there's probably no better way to get a large amount of coal burning as fast as possible.