Citing the release of millions of gallons of toxic wastewater into a southwestern Colorado river earlier this month, a coalition of conservation groups, two Arizona Native American tribes and two county governments petitioned federal agencies Tuesday to tighten mining regulation on public lands.

A federal appeals court Monday upheld the government’s decision to let a uranium mine near Grand Canyon National Park continue to operate under environmental standards now decades old.

A trio of environmental groups has followed through on a threat to sue the Bureau of Land Management for giving a green light to a uranium-mine north of the Grand Canyon.