U.S. government attorney Jen Pepin said the U.S. Forest Service plans to re-publish an environmental report before July that will set in motion a land swap between the U.S. government and Rio Tinto that would pave the way for the development of the Resolution Copper Project.

Native American Tribes led by the group Apache Stronghold have opposed the mine, arguing that it destroy an area known as Oak Flat. The group says the area hold religious importance to Native Americans.

The Apache group is seeking to halt the land swap while the case plays out in court. The panel of 11 judges on the 9th U.S. Circuit Court of Appeals is expected to issue a decision in the next few months.

The land swap was passed by Congress in 2014. It would give Resolution Copper 9.71 km (3.7 sq miles) of national forest land in exchange for eight parcels it owns in other parts of Arizona to the develop the mine that contains a reserve of more than 40 billion lbs of copper. The land swap would require an environmental report to be published which was done by Trump administration shortly before leaving office. President Joe Biden then unpublished that report in March 2021 to give his administration time to review the Apache's concerns, though he was not able to permanently block the mine.

Reuters reporter that the Apache Stronghold sued to prevent the transfer of the federally-owned Oak Flat Campground.

Pepin told an en banc hearing of the 9th U.S. Circuit Court of Appeals on that “the prediction for that (new environmental report) is to be ready this spring.”

The Forest Service is not waiting for the court's ruling to publish the new report, Pepin said, adding that the agency does not believe an 1852 treaty between the U.S. government and Apaches gives Native Americans the right to the land containing the copper.

“This particular treaty is just a peace treaty. It doesn’t settle any rights to land and it doesn’t create any land rights,” Pepin told the court.

The 11 judges at the hearing questioned all sides about the legal concept of substantial burden and whether the government can do what it want with federal land, even if it prevents some citizens from fully exercising their religious beliefs. A full ruling is expected in the near future.

A Rio Tinto spokesperson told Reuters that the company is closely following the case and respects the legal process, but believes “that settled precedent supports” the rejection of Apache Stronghold's claims by a lower court. Rio has said it will smelt copper from the project inside the United States.