The 9th U.S. Circuit Court of Appeals heard oral arguments Monday in a case involving a copper mine in the Santa Rita Mountains southeast of Tucson.

If approved, Rosemont would be the third-largest copper mine in the country.

A coalition of conservation groups and tribes says that the U.S. Forest Service failed to protect public lands as the project moved forward.

In the summer of 2019, a U.S. District judge agreed.

The two sides clashed over a proposal to dump waste on public lands located two miles from the mine. Roger Featherstone of the Arizona Mining Reform Coalition says the case challenges the agency’s interpretation of the 1872 mining law.

"As long as they want to mine, we gotta do what they want to do pretty much. Well, that may be the way the Forest Service has operated for the last 30 years but it doesn’t mean that it’s right," Featherstone said.

Conservationists say that Rosemont would damage important habitat for endangered species such as the jaguar.