Mining company Perpetua Resources has secured a $2.9 billion loan from the U.S. Export-Import Bank, CNBC has learned. The deal comes as the U.S. looks to secure access to critical minerals and break China’s stronghold on essential supply chains.

The financing, which is the largest loan under EXIM’s “Make More in America” initiative and the agency’s fourth largest loan on record, will fund Perpetua’s Stibnite Gold project in Idaho. The mine will also produce antimony, which is essential for defense applications – including for munitions – as well as semiconductor manufacturing and renewable energies including solar panels and wind turbines, among other things.

Perpetua shares rose more than 12% on the news.

The U.S. Geological Survey deems antimony a “critical mineral.” There are no antimony mines currently in operation in the U.S. China is the dominant producer of antimony globally, satisfying more than half of U.S. demand, according to USGS.

The Stibnite site is the only source of domestic antimony that can meet the U.S.’ requirements for weapons production, according to the company, with the ability to supply about 35% of U.S. demand within the first six years of production.

This is the latest in a string of deals from the government focused on shoring up domestic production of critical minerals, especially as China has in the past weaponized natural resources by curbing exports.

In February, the White House unveiled “Project Vault,” a first-of-its-kind public-private partnership focused on stockpiling minerals. The $12 billion initiative includes $10 billion in funding from the Export-Import Bank, and an additional $2 billion in private capital. 

The administration has also taken equity stakes in mining companies directly, including rare earths producer MP Materials. In July the Pentagon announced an investment in the company that includes an offtake agreement as well as a price floor. The U.S. was once the largest rare earths producer, but output plummeted after China flooded the market and depressed prices. The government has also inked deals with miners including USA Rare Earth, Lithium Americas and Trilogy Metals. Shares of all three stocks traded higher on Thursday.

Perpetua has begun construction on the Stibnite site and said it should be operational in 2029. The company is working with the Department of Defense to supply antimony, and is in the process of securing additional commercial partners.