Mining is currently threatening Lake Superior watersheds -- both on the Michigan and the Minnesotan shores. I don't have as much information about the Canadian shore and watersheds.
It's also threatening the Boundary Waters of Minnesota/Canada -- a famed nature-intense recreation area.
In many of these projects, companies want to mine lower grade sulfate ores. This creates a tremendous problem of acidification, which leaches all sorts of things and especially heavy metals from the tailings. Things that disperse into the environment and never go away. And that, history demonstrates, are practically impossible to contain.
Mitigation plans are written on 50 and some magical 500 year plans. Neither of which suffice with respect to the continuing presence of the toxic byproduct. Not to mention, that most companies don't even survive the lesser timeframe, and that they have always chosen to spend money on lawyers to evade their obligations rather than on cleanup costs -- until coerced, and if there are even any non-disbursed company funds left to pay for same.
I think our next generation energy resources development is essential. But along with it should come 100% recycling of the metals and as much other involved materials, as possible.
Governments should also insist on pro-actively funded mitigation trusts that exist separate from both company and government and cannot be "raided" by other for other expenditures.
How that competes with extra-territorial, natural resource poisoning competition? Well, that's a corner that the U.S. and Canada, among many others, have well painted themselves into.
P.S. I forgot to mention Wisconsin, sharing the south shore with Michigan. A proposed mine there threatened (threatens -- have they really given up?) the Bad River Reservation including the Reservation's wild rice beds. And if you think "what's a little wild rice?", well, aside from treaty obligations (are we really going to continue to break those?), consider it a harbinger of broader impact, as well as taking away self-sufficiency and cultural heritage from a chronically, coercively disadvantaged population.
And consider that, long term, the environment holds much more opportunity -- including essential health -- than a mine that will ruin same while exporting most of its economic gains outside the community.