I'm really sure that it's coincidental, but I just moved 60 John Prine songs to my new phone so I can listen as I ride.

Tailings piles. For the gold mines they are incredibly toxic due to using arsenic to flush the flake gold out that they couldn't recover originally. At least two copper mines that I am aware of used 'liquid tailings'. Add lots of water and pump them miles to a convenient valley. Convenient for the mine, not for the valley. What could possibly go wrong? Uranium is in a league all it's own. So far as I know none of the old mines inside Grand Canyon NP HAVE NOT been stabilized. Sigh. The progress of man indeed.