The vast majority of Arizonans want to keep the current ban on mining in place.

think-progress:

A dark money group backed by Charles and David Koch is behind a well-funded effort to undermine protections at the Grand Canyon and overturn the Antiquities Act, the law President Teddy Roosevelt used to permanently protect the area in 1908. If successful, the campaign could stop a permanent ban on uranium mining near the canyon’s rim, despite support for such a ban by a vast majority of Arizonans.