Mr. Jon Cherry reports

PERPETUA RESOURCES PROVIDES CONSTRUCTION UPDATE ON THE STIBNITE GOLD PROJECT AND EXPLORATION ACTIVITIES

Perpetua Resources Corp. today provided an update on critical path construction progress at its Stibnite gold project in central Idaho. With federal approvals secured in 2025 and early works and critical path construction activities under way, the company is pleased to provide updates to shareholders and communities with a clear view of activity on the ground.

"We continue to see tangible progress at Stibnite," said Jon Cherry, president and chief executive officer of Perpetua Resources. "From the arrival of new infrastructure on site and advancements in equipment fabrication to exciting drilling results, this update demonstrates the momentum, focus and disciplined execution our team is bringing to the project."

Recent highlights

Stibnite autoclave fabrication under way

After submitting purchase orders earlier this year, essential components of the Stibnite gold project's dual autoclaves are being fabricated at a custom facility in Europe. The curved plates depicted here are rolled to meet exact standards to fit the autoclave vessel's specified radius before being welded together.

These long-lead equipment items represent key components of the Stibnite processing facility to optimize gold extraction.

Worker housing takes shape

Temporary work force housing is in place, and Perpetua is now advancing the permanent worker housing facility for the long-term accommodation of the project's construction and operations work force. Designed to be self-contained and support year-round activity in a remote environment, the modular units will form the core of the site's workforce lodging throughout the project life.

As of Aug. 24, 2026, approximately half of the ATCO-supplied units have been delivered to Stibnite. The remaining units are staged 75 miles away in Cascade, and deliveries occur nearly every day. The permanent facility location at Stibnite is ready for installation as grading has been completed and utilities are installed.

Additional on-site preparation

Key infrastructure construction continues at the Stibnite gold project, including the administrative pad area on site and the Burntlog Route. The initial buildout of the administrative pad is under way, which will include a variety of administrative infrastructure, emergency services and other support facilities. The U.S. Forest Service officially identified the Burntlog Route as the preferred alternative and environmentally preferred alternative under NEPA. Once the Burntlog Route is completed, it will be the main access route to the Stibnite gold project.

Drilling intensifies with four rigs

With significant mineralization identified in the company's winter drill program (as noted in the Aug. 6 press release), staff continue to drill prospective targets. Exploration drilling is currently under way with four rigs and approximately 5,800 metres of the new 10,000-metre drill program completed to date.

Rigs are spread across various targets, including:

• Clark Tunnel Fault zone (CTFZ): Located within or adjacent to the southeastern limits of the Yellow Pine pit, the CTFZ returned near-surface, high-grade gold intercepts from recent drilling, including 6.4 metres of 16.2 grams per tonne gold and 1.7 per cent antimony from surface and 15.0 metres of 6.3 g/t gold and 0.8 per cent antimony from an 11-metre depth. As these intercepts demonstrate mineralization that is near surface, within the permitted pit footprint, and at grades that are multiples of reserve grade, Perpetua has elected to continue testing the CTFZ as part of its 10,000-metre 2026 drill program.

In addition to high-grade gold, Perpetua also made a new gold-tungsten discovery of 21.3 metres of 3.2 g/t gold and 0.9 per cent tungsten from a 24-metre depth. Additional occurrences of scheelite, a tungsten-bearing mineral, have been observed in continuing drilling in the CTFZ.

• Huckleberry Fault zone (HFZ): Lying immediately adjacent to the Yellow Pine reserve pit limits, widely spaced drilling and surface sampling at the HFZ returned broad intervals of gold mineralization, including 69.6 metres of 0.8 g/t gold, akin to the nearby West End reserve pit.
• Hangar Flats: Drilling continues to focus on high-grade gold, antimony and tungsten targets at Hangar Flats. Initial drilling tested near-surface targets in the Hangar Flats extensions, including 3.0 metres grading 14.5 g/t gold. Deeper drilling beneath the reserve pit returned high-grade antimony and tungsten intercepts, including 22.9 metres of 3.2 per cent antimony and 1.2 per cent tungsten, 9.8 metres of 8.3 per cent antimony and 4.6 per cent tungsten, and 3.4 metres of 10.6 per cent antimony and 1.5 per cent tungsten. Any tungsten development would require separate environmental review and permitting outside the current project's scope.

Perpetua, U.S. Army and Idaho National Laboratory open antimony processing plant

Perpetua Resources, the U.S. Army and Idaho National Laboratory (INL) held a ribbon cutting on July 29, 2026, for a modular mineral processing plant at INL in Idaho Falls, attended by Idaho's governor, lieutenant governor and Idaho Congressman Mike Simpson.

The plant will initially process antimony samples from Perpetua's Stibnite gold project into antimony trisulphide for military use, aiming to rebuild a domestic "ground-to-round" supply chain after China cut off U.S. access to this material in 2021. Antimony trisulphide continues to play an important role in ammunition manufacturing and other military applications. It also plays an integral role in batteries, solar glass and flame retardants needed by domestic manufacturers. The pilot plant project stems from a multiyear partnership between Perpetua and the U.S. Army's Defense Ordnance Technology Consortium. Since 2022, Perpetua has been awarded over $87-million from the U.S. Department of War and the U.S. Army, including more than $59-million in Defense Production Act funds and a recent $4.7-million award that brought total army funding under the ordnance technology initiative agreement (OTIA) to $27-million.

Stibnite holds the only identified antimony reserve in the U.S. and historically supplied over 90 per cent of the antimony and over 50 per cent of the tungsten used by the U.S. government during the Second World War. The Stibnite gold project received final federal approval in 2025 allowing construction to proceed and is now in early works and critical path construction, positioning it to supply both antimony and gold while supporting national security and Idaho's economy.

New Yellow Pine community outpost

On Thursday, July 16, Perpetua Resources proudly celebrated the grand opening of The Outpost, a new community resource and visitor information center located in Yellow Pine, Idaho. The event brought together employees, community members, local partners and visitors to mark an exciting milestone for both the company and the community.

The Outpost was created to serve as a welcoming space where residents, visitors, recreationists and anyone interested in the area can learn more about the Stibnite gold project. Visitors can view educational displays, ask questions and receive the latest project updates in a space designed to foster open dialogue and meaningful engagement with the community.

Litigation update

On Aug. 18, 2026, the U.S. District Court of Idaho issued a comprehensive ruling affirming the U.S. Forest Service's and other federal agencies' approval of the Stibnite gold project. The court upheld the federal approvals for the project, rejecting the plaintiffs' challenges that the agency decisions violated the National Environmental Policy Act, the General Mining Law and the National Forest Management Act, among other federal laws.

The court further upheld the substance of the federal agencies' decisions under the Endangered Species Act (ESA), including that the project would not jeopardize any endangered species. On a narrow, discrete issue, the court remanded back to the U.S. Fish and Wildlife Service (FWS) the agency's incidental take statements, which implement some of the ESA requirements for the project. The court instructed FWS to clarify monitoring and reporting measures contained in the existing agency record. The court's remand does not require reconsideration of the FWS's no-jeopardy findings. Plaintiffs have filed an appeal of the district court's decision. However, based on the district court ruling and its earlier denial of the plaintiffs' motion for preliminary injunction, Perpetua continues to move forward with various critical path construction activities.

About Perpetua Resources Corp. and the Stibnite gold project

Perpetua Resource, 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. The Stibnite gold project is one of the highest-grade, open-pit gold deposits in the United States and holds the only identified domestic reserve of the critical mineral antimony, which is essential to the defence, energy and manufacturing sectors. The project is designed to apply a modern, responsible mining approach to restore a historic mine site and provide uplift to water quality, improve fish habitat access, and invest in river restoration while supporting local economic development in rural Idaho.

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