>>1363889Just research old mining maps, most of them are not going to be near big cities. They can be very dangerous, I've been 100 ft into an abandoned silver mine and 200-ish ft into a copper test shaft in AZ before and it is very easy to potentially get lost, though it is not illegal if the mine is on public land and abandoned. The USGS just discourages it because it is dangerous. There are 100k + in AZ alone, CO probably has its fair share of them as well. Do NOT go in one alone. Pic related is the copper shaft.
