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Perpetua Resources Partners with the Idaho National Laboratory to Advance Critical Mineral Pilot Plant

Metallurgy & Processing Partnerships & JV

405 S 8th Street #201, Boise, ID 83702

NEWS RELEASE

December 9, 2025

Perpetua Resources Partners with the Idaho National Laboratory to Advance Critical

Mineral Pilot Plant

BOISE, ID – Perpetua Resources Corp. (Nasdaq: PPTA / TSX: PPTA) (“Perpetua Resources” or “Perpetua”

or the “Company”) today announced that it has entered an agreement with the Idaho National

Laboratory (“INL”) via Battelle Energy Alliance LLC (“Battelle”) for the INL to host, commission, and

operate a flexible, modular pilot processing plant expected to be capable of recovering various critical

and defense-related minerals, including antimony from the Company’s ores. This initiative is intended to

demonstrate the feasibility of producing high- quality, military specification antimony trisulfide using

material from Perpetua’s Stibnite Gold Project (“Project”). In addition, it will provide opportunities to

advance domestic defense mineral processing capabilities and strengthen workforce training in Idaho.

“We are proud to collaborate with Idaho National Laboratory to further strengthen America’s defense

capabilities and help secure a domestic source of antimony trisulfide,” said Jon Cherry, President and

CEO of Perpetua Resources. “This partnership highligh ts Idaho’s role in national security and

demonstrates our ongoing commitment to responsible resource development, job creation, and

workforce training in Idaho. The successful demonstration of this plant will contribute to sustained

growth in American mineral independence and resilience.”

Locating the pilot plant at INL leverages the lab’s critical and strategic materials and defense programs.

Trained operators and specialized staff members will commission and operate the plant, which will

consist of several modular containers with the necessary equipment to conduct pilot-scale testing. Once

installed, the pilot plant will receive samples of material from the Stibnite Gold Project and operators will

conduct pilot -scale testing to produce antimony trisulfide concentrate needed for munitions and

advanced systems used by U.S. military personnel.

This pilot plant initiative is part of a broader partnership between Perpetua Resources and the U.S. Army

via the Defense Ordnance Technology Consortium (“DOTC”) to secure domestic sources of critical

minerals. In May 2025, Perpetua was awarded up to $6.9 million in additional DOTC funding, bringing

the Company’s total DOTC awards up to $22.4 million. This extended award combines Perpetua’s Idaho-

based antimony resource with INL’s world-class scientific research capabilities to support the U.S. Army’s

objective of establishing a fully domestic “ground-to-round” antimony trisulfide supply chain.

“This partnership brings together Perpetua’s antimony resources with INL’s expertise in materials

processing to address a critical national security need,” said John Wagner, INL Director. “Establishing

domestic production capabilities for antimony trisulfi de essential for munitions and defense systems

strengthens America’s supply chain resilience while advancing Idaho’s leadership in critical minerals and

workforce development.”

Critical materials research at INL concentrates on the components essential for energy and national

security. INL has expansive expertise, including cutting-edge research areas like mineral characterization,

geochemical modeling, and material separation.

Responsible Mining. Critical Resources. Clean Future.

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U.S. House Representative Mike Simpson (R -Idaho) applauded t oday’s announcement, stating, “As a

longtime supporter of the Idaho National Laboratory and Perpetua Resources’ efforts in domestic

antimony production, I am thrilled to see this partnership come together. Idaho has the potential to

provide our country with a domestic source of critical minerals that are essential to our national security

needs. This partnership is a win for Idaho, and I am pleased to see our great state once again play such

a pivotal role on the world stage.”

The Stibnite Gold Project is the only identified reserve of antimony in America. The Company expects to

supply up to 35 percent of U.S. antimony demand during its first six years of operations while meeting

long-term Department of War antimony needs. In addition to providing for American national security,

the Project will create hundreds of family -wage jobs, restore fish access to critical spawning habitat,

address legacy environmental degradation, and improve water quality at an historical abandoned mine

site.

About Perpetua Resources and the Stibnite Gold Project

P e r p e t u a R e s o u r c e s C o r p . , t h r o u g h i t s w h o l l y o w n e d s u b s i d i a r i e s , i s f o c u s e d o n t h e e x p l o r a t i o n , s i t e

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 Stibnite Gold 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

identified reserve of antimony in the United States. Antimony trisulfide from Stibnite is the only known

domestic reserve of antimony that can meet U.S. defense needs for many small arms, munitions, and

missile types.

About Idaho National Laboratory

INL is the nation's center for nuclear energy research and development, also focusing on strategic

national security technologies, critical minerals, energy, and workforce development to sustain American

competitiveness and security. Perpetua's agreement with INL is through Battelle Energy Alliance, which

manages INL for the Department of Energy.

About the Department of Defense Ordnance Technology Consortium

The DOTC serves as the focal point for armaments system technology research and development. The

industrial and academic component of DOTC is the National Armaments Consortium (“NAC”), which

consists of over 1,000 companies.

D O T C ’ s m i s s i o n , i n p a r t n e r s h i p w i t h N A C , i s t o e n h a n c e o u r w a r fi g h t e r s ’ l e t h a l i t y , s u r v i v a b i l i t y a n d

combat effectiveness by facilitating the industrial and academic research, development and technology

demonstrations needed to advance and expand our milit ary technological superiority. DOTC is

sponsored by the Office of the Secretary of Defense and is utilized by all Services and Defense Agencies

to design, develop and demonstrate prototypes for armaments. NAC is the largest collaborative

organization worki ng with the DoD to develop armament technologies in support of our nation’s

security.

The NAC is comprised of our nation’s leading technologists, engineers, designers, scientists,

manufacturers, and program managers across industry, academia and our nation’s laboratories, all with

the mission to develop armaments that give the U.S. a techno logical edge over our enemies. Together,

DOTC offers government customers a better way of doing business through streamlined acquisition and

collaboration across a broad spectrum of industrial and academic partners.

For more information, visit www.perpetuaresources.com.

Responsible Mining. Critical Resources. Clean Future.

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Contacts:

Joe Fazzini

Vice President, Investor Relations

[email protected]

[email protected]

Chris Fogg

Investor Relations Manager

[email protected]

[email protected]

Mckinsey Lyon

Vice President External Affairs

[email protected]

FORWARD-LOOKING STATEMENTS

Statements contained in this news release that are not historical facts are "forward-looking information" or "forward -

looking statements" (collectively, "Forward-Looking Information") within the meaning of applicable Canadian securities

legislation and the United States Private Securities Litigation Reform Act of 1995. Forward- Looking Information includes,

but is not limited to, the anticipated benefits from the partnership with INL; the timing and results of future material

sampling conducted by the Compan y and adjustments to the modular pilot plant design and construction; expected

commercial demand for antimony and the Company’s ability to supply it; our ability to successfully implement and fund

the Project; and the occurrence of the expected benefits from the Project, including creation of jobs, environmental benefits

and providing a domestic source of antimony and national defense benefits. In certain cases, Forward-Looking Information

can be identified by the use of words and phrases or variations of such words and phrases or statements such as

"anticipate", "expect", "plan", "likely", "believe", "intend", "forecast", "project", "estimate", "potential", "could", "may", "will",

"would" or "should". In preparing the Forward-Looking Information in this new s release, Perpetua Resources has applied

several material assumptions, including, but not limited to, that the current financing, exploration, development,

environmental and other objectives concerning the Project can be achieved and that its other corpor ate activities will

proceed as expected; and that general business and economic conditions will not change in a materially adverse manner

and that construction and operations costs will not materially increase. Forward- Looking Information involve known and

unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements of

Perpetua Resources to be materially different from any future results, performance or achievements expressed or implied

by the Forward-Looking Information. Such risks and other factors include, among other things, risks related to unforeseen

delays in the review and permitting process, including as a result of legal challenges to the ROD or other permits; risks

related to opposition to the Project; risks related to increased or unexpected costs in operations or the permitting process;

risks that necessary financing will be unavailable when needed on acceptable terms, or at all, as well as those factors

discussed in Perpetua Resources' public fil ings with the U.S. Securities and Exchange Commission (the "SEC") and its

Canadian disclosure record. Although Perpetua Resources has attempted to identify important factors that could affect

Perpetua Resources and may cause actual actions, events or resul ts to differ materially from those described in Forward-

Looking Information, there may be other factors that cause actions, events or results not to be as anticipated, estimated or

intended. There can be no assurance that Forward-Looking Information will p rove to be accurate, as actual results and

future events could differ materially from those anticipated in such statements. Accordingly, readers should not place

undue reliance on Forward-Looking Information. For further information on these and other risk s and uncertainties that

may affect the Company's business, see the "Risk Factors" and "Management's Discussion and Analysis of Financial

Condition and Results of Operations" sections of the Company's filings with the U.S. Securities and Exchange Commission

(the "SEC"), which are available at www.sec.gov and with the Canadian securities regulators, which are available at

www.sedarplus.ca. Except as required by law, Perpetua Resources does not assume any obligation to release publicly any

revisions to Forward-Looking Information contained in this news release to reflect events or circumstances after the date

hereof or to reflect the occurrence of unanticipated events.