Originally Posted by allmywires
May be a tad late for this but I think I can help
Most ore mining will involve some sort of waste, called tailings, which is usually stored in a tailings pond. These can be huge and they're usually highly acidic and extremely dangerous (hence as I expect you know, the need for making sure the ponds are very, very leak-proof). It's pretty much inescapable - you're digging this stuff out the ground to get a tiny end product, what happens to the rest of it? Spoil heaps can also be huge and dangerous, if not properly secured bad weather can cause slumps and huge scale destruction.
Hope it helps! Geologist(ish) here for all your geological needs.
Thank you for the information. I had no idea about the tailings, and especially tailing ponds. A tailing pond leaking can provide a very realistic reason on why all the water is being ruined.