Conventional "C" class corporations have the law slanted in favor of maximizing profits for the share-holders. A "Benefit" corporation however, can have bylaws which demand stewardship of the environment, and allow for processes which protect the environment, and also set aside some of the profits for reclamation.
Donlin and Pebble could be very clean operations, only if the greedy share-holders didn't have sway over operations. Couple that with 100% local hire, of people who have a stake in their environment; and dry stacking, calcite neutralizing of acidic tailings, back-filling of the pit, enough gas and electricity to use the cleanest possible processes, dumping the worst of the tailings into the Pacific Subduction Zone, some "proof-of-concept testing", and it might work.
I have prodded our legislators to pass a bill for benefit corporations, but I'm only one voice, drowned out by  a hurricane of lobbyists pushing other issues.
Wikipedia has an article on benefit corporations.