MOU signed to explore feasibility of utilizing Sunshine Silver’s permitted antimony plant site to process concentrates from both Stibnite Gold and Sunshine Silver.

Antimony concentrate from the Stibnite Gold Project could be processed alongside Sunshine Silver’s own production, together achieving up to 40% of annual U.S. antimony demand

Perpetua Resources Corp. (Nasdaq: PPTA) (TSX: PPTA) announced its wholly owned subsidiary Perpetua Resources Idaho, Inc. has entered into a Memorandum of Understanding to explore antimony processing opportunities with Sunshine Silver Mining & Refining Company, also based in Idaho.

Testing under the MOU, which is non-binding and non-exclusive, will evaluate the technical potential for processing and refining antimony from the Stibnite Gold Project in Idaho at the Sunshine Mine Complex. The MOU will initiate third-party engineering to evaluate a flowsheet to suit different antimony ore types and follows engagement between the parties’ technical and executive teams.

“Perpetua’s MOU with Sunshine Silver is a step in evaluating a fully integrated American antimony supply chain,” said Jon Cherry, President and CEO of Perpetua Resources. “The Stibnite Gold Project is the only identified domestic reserve of antimony, and with final federal decisions expected in a matter of weeks, Perpetua is ready to work with U.S. companies to help secure domestic production of antimony.”

“A fully American antimony supply chain is paramount for U.S. national and economic security,” said Heather White, CEO of Sunshine Silver. “We are confident that Sunshine can process and produce high-grade antimony here in Idaho as we have done in the past. Collectively, Sunshine and Perpetua plan to work under the MOU to identify a framework to develop a truly end-to-end American antimony solution.”

On December 3, 2024, China, which dominates antimony production, refinement, and processing capabilities globally, announced an enhanced ban on exports of antimony to the United States. This move comes after the Chinese Communist Party announced global export restrictions on antimony in August 2024.  Antimony is essential for national defense, clean energy and technology applications. Antimony is a primer in hundreds of munition types, a doping agent in semiconductors and printed circuit boards, and a central component in solar panels and wind turbines. No domestically mined supply of antimony currently exists. The Stibnite Gold Project has a reserve of 148 million pounds of antimony, making it one of the largest reserves of antimony not under Chinese influence and the only U.S. domestic reserve. The Stibnite Gold Project is expected to supply about 35 percent of projected U.S. antimony demand in the first six years of operations, based on the 2023 USGS antimony commodity summary. This Perpetua production, if added to the 5 percent that Sunshine has indicated it expects to be able to produce, could provide up to 40 percent of U.S. antimony demand.

The Stibnite Gold Project received its Final Environmental Impact Statement (“FEIS”) and Draft Record of Decision in September 2024, is designed to restore a historic mining district abandoned after 100 years of mostly unregulated mining while producing gold and the only reserve of antimony in the United States. Based on the U.S. Forest Service (“USFS”) schedule published in July 2024, the Final Record of Decision is scheduled for delivery at the end of 2024.

About Perpetua Resources and the Stibnite Gold Project

Perpetua Resources Corp., through its wholly owned subsidiaries, is focused on the exploration, site restoration and redevelopment of gold-antimony-silver deposits in the Stibnite-Yellow Pine district of central Idaho that are encompassed by the Stibnite Gold Project.  The Project is one of the highest-grade, open pit gold deposits in the United States and is designed to apply a modern, responsible mining approach to restore an abandoned mine site and produce both gold and the only mined source of antimony in the United States. Further advancing Perpetua Resources’ ESG and sustainable mining goals, the Project will be powered by one of the lowest carbon emissions grids in the nation and a portion of the antimony produced from the Project will be supplied to Ambri, a U.S.-based company commercializing a low-cost liquid metal battery essential for the low-carbon energy transition. Perpetua Resources has been awarded a Technology Investment Agreement (“TIA”) of $59.2 million in Defense Production Act Title III (“DPA”) funding to advance construction readiness and permitting of the Project. Antimony trisulfide from Stibnite is the only known domestic source of antimony that can meet U.S. defense needs for many small arms, munitions, and missile types. In addition to the company’s commitments to transparency, accountability, environmental stewardship, safety and community engagement, Perpetua Resources adopted formal ESG commitments which can be found here.

About Sunshine

Sunshine Silver Mining & Refining Company is dedicated to bringing the iconic permitted Sunshine Mine back into production. As the largest mineral rights holder in Idaho’s Coeur d’Alene Mining District – the most productive silver region in the United States – Sunshine benefits from a stable regulatory environment, a highly skilled workforce, excellent infrastructure and a deeply-rooted mining culture. Boasting a total resource grade of 25.9 ounces silver per ton (888 grams silver per metric tonne), the Sunshine Mine ranks among the world’s highest-grade silver deposits. This, combined with the Mine’s valuable copper and, in particular, antimony byproducts, provides Sunshine with exceptional exposure to metals that are crucial in the 21^st century economy. The mine hosts 277 million ounces of silver, including over 112 million ounces in the Indicated category, with excellent exploration results underscoring its substantial growth potential, especially in silver and antimony. The Company is vertically integrated, with a permitted silver refinery on site, able to produce COMEX-grade silver and copper cathode.  Permits are also in place to produce and process the critical metal antimony.