The indigenous groups thought they had reached a deal: A vast landscape in the north of Yukon Territory would be mostly set aside for preservation, with only a small percentage allotted to industrial development.

But then the Yukon government decided to push aside this recommendation agreed to by a joint government-indigenous commission.

Instead, it favored far more development in the wilderness, which has huge deposits of coal, gas and minerals, including 18 billion tons of iron ore claimed by Chevron, the American petroleum giant.

Now the 26,000 square miles of the Peel Watershed — an area larger than the state of West Virginia where mountain sheep graze on the sides of snow-capped peaks, and grizzlies and wolves hunt caribou and moose along the banks of six pristine rivers — is at the heart of a legal battle before Canada’s Supreme Court.