Dang, that's scary. Montana passed a cyanide ban - state wide - through a voter initiative. So far it's not been legally challenged, at least successfully. The "mining interest" had some legal/financial issues and kind of dropped away. I'm sure someday some company will step in and try to fight it. the mine that prompted it was to be at the headwaters of the Blackfoot, think Norman McLean's "A River Runs Through It".
Living in Montana, boating in Idaho