Exploration and development company Perpetua Resources has secured a key US Forest Service authorisation to begin development of its Stibnite gold and antimony project in Idaho, clearing the way for construction after nearly a decade of federal permitting.

The conditional notice to proceed confirms the project has met all requirements under the January 2025 record of decision. The only remaining step before initial work can begin is the posting of a joint financial assurance bond, agreed to with the Forest Service, the Idaho Department of Lands and the US Army Corps of Engineers.

“After 8 years of extensive permitting review and over $400-million invested, it is finally time for the Stibnite gold project to deliver for America,” president and CEO Jon Cherry said in a statement. He added: “With the US Forest Service’s notice to proceed and the joint financial assurance package approved, we are ready to begin to bring Stibnite back to life as a national strategic asset.”

The project would provide the only US source of mined antimony, a mineral critical for munitions and defence technologies, while also producing gold and remediating legacy environmental damage at the historic Stibnite site. Perpetua said it expected to post the required financial assurance in the coming weeks, allowing early construction to start this fall.

“Completing federal permitting for Perpetua Resources’ Stibnite gold project is a major step towards unlocking America’s critical minerals resources. By redeveloping this historic mining site, we can both restore the environment and secure a domestic supply chain that is essential to our nation’s future," said federal permitting improvement council executive director Emily Domenech.

The Stibnite project, listed under the Trump administration’s FAST-41 programme to streamline permitting, has drawn more than 23 000 supportive public comments. Its mine plan includes habitat restoration, footprint reductions and improved water quality.

Cherry said the mine is “poised to once again produce minerals critical to national security and defence, just as it did during World War Two".