The Arizona Department of Environmental Quality is taking public comments on a plan to issue a new Aquifer Protection Permit for a uranium mine outside the Grand Canyon. Conservationists have been battling the mine for years.

The mine used to be called the Canyon Mine, but the company that owns it, Energy Fuels Incorporated, recently changed the name to Pinyon Plain Mine. Critics are concerned that the mine will harm the Havasupai Tribe’s drinking water supply.

In 2016, Energy Fuels struck an aquifer in the mine shaft and since then has had to pump out more than 40 million gallons of contaminated water. Sierra Club spokeswoman Sandy Bahr said there are concerns the mine could cause more damage if it is allowed to proceed.

“Once the waters are contaminated with uranium there’s really no way to clean it up,” Bahr said.

Members of the public have until Aug. 7 to comment.