The company plans a ceremony with investors and politicians at its Stibnite project, about 138 miles (222 km) north of Boise, after a conditional notice to proceed from the U.S. Forest Service, but actual constructin is to start by October.
The green light for the mine, backed by billionaire investor John Paulson, comes after Beijing last year blocked exports to the United States of antimony, a metal used to make bullets, solar panels and other goods.
There are no current U.S. sources of the metal.
The project received its mining permitin January, provided several minor conditions were met.
Friday's move is essentially an acknowledgement by President Donald Trump's administration, which has supported the mine, that those conditions were satisfied.
"Completing federal permitting for Perpetua Resources’ Stibnite Gold Project is a major step towards unlocking America’s critical minerals resources," said Emily Domenech, executive director of the government's permitting council.
Boise, Idaho-based Perpetua must finalize a reclamation bond for the mine, a routine step expected to wrap up within a few weeks.
The mine will supply more than 35% of America's annual antimony needs once it opens by 2028 and produce 450,000 ounces of gold each year.
The dual revenue stream is expected to keep the project financially afloat regardless of any steps by Beijing to sway markets. The site has estimated reserves of 148 million pounds of antimony and 6 million ounces of gold.
Last April, Perpetua received a letter of interest from the U.S. Export-Import Bank, the government's export credit agency, for a project funding loan worth up to that is still under review.
The project has faced opposition from Idaho's Nez Perce tribe, which is concerned the mine could affect the state's salmon population.
