The fate of Arizona’s planned Resolution Copper Mining copper-molybdenum mine is up in the air after the Biden administration reversed course, rescinded two key environmental documents and blocked a pending land swap that would have allowed the Rio Tinto-BHP joint venture to proceed.

The federal Environmental Impact Statement that had been issued on 15 January by the Tonto National Forest in the closing days of the Trump administration was withdrawn Monday afternoon by the US Forest Service, Kallanish reports. That agency was directed to rescind the document by the US Department of Agriculture of which it is part. That blocks the planned land swap that was to have been completed by 15 March and includes Oak Flat, an area held sacred by Apaches.

The Forest Service says “additional time” is needed to understand the concerns of the tribes and the public toward the project that would be near Superior, Arizona, and about 96 kilometres east of Phoenix.

“USDA has concluded that additional time is necessary to fully understand concerns raised by tribes and the public and the project’s impacts to these important resources and ensure the agency’s compliance with the federal law,” it says in a statement. Tonto officials say a recent memorandum issued by President Joe Biden on tribal consultation and strengthening relationships was also a factor in the decision that came as a surprise to many.

Such a review is likely to take several months but only Congress that had approved the Resolution mine project in 2014 can permanently protect Oak Flat, the USFS says.

The companies have not issued any statements about the move by the Biden administration. The news was hailed by tribal leaders and conservation groups and blasted by politicians including Arizona Governor Doug Ducey, according to Arizona media.

Resolution Copper Mining has been working since 2013 to develop the project that could produce 120,000 tonnes of ore/year and 40 billion pounds of copper over 40 years. It could produce 25% of the US copper demand and create 1,500 mining jobs. The company has spent $2 billion on the project. It intends to conduct a feasibility study over several years, after the permitting process is completed. That will enable the company to make a final investment decision and building infrastructure may take up to 10 years before mining begins, it says.

Three lawsuits have been filed to block the project.