LOL did you look at what they say about KSM?

http://wildborderwatersheds.org/projects/kerr-sulphurets-mitchell

KSM poses the biggest single threat to rivers and salmon in the transboundary region. At the mine site, the mineralized rock has high sulfur content with a high probability for acid generation. Current plans for water treatment at the site are unprecedented in scale and rely on unproven technology. Potentially acid-generating waste rock would remain a long-term concern for the Unuk River, which provides spawning routes for Pacific salmon and steelhead trout, habitat for cutthroat and rainbow trout, char, and whitefish, and flows into Misty Fjords National Monument in Alaska. In Canada, more than 2 billion tons of tailings waste would be stored in two tailings impoundments between Teigen and Treaty Creeks – a part of the Nass watershed that provides spawning or other habitat for chinook, coho and sockeye salmon, steelhead, rainbow and bull trout, Dolly Varden char and mountain whitefish.