Some guy down there was keeping in shape by running in the tunnels...

I went into an underground coal mine in AL down to about 500', just once. Never again. I've got no problem cave crawling, but the coal mine is spookier, and I never trusted pine for shoring posts.

I lost a good high school friend who majored in mining engineering and went to work in an Ohio underground coal mine, and had the damn thing blow up with him in it only a year or two out of 'Bama. RIP, Dickey...

Not responsible for advice not taken...