Perpetua Resources (TSX, Nasdaq: PPTA) is moving forward with early construction at its Stibnite gold-antimony project in Idaho after a U.S. federal court upheld key project approvals in the face of an environmental challenge.

The Aug. 18 ruling dismissed challenges brought under several federal laws and upheld findings that the $1.3-billion (C$1.8-billion) Stibnite project would not jeopardize protected species. An appeal is pending, but construction can continue, National Bank of Canada said in a note on Monday.

"We view the merits ruling as a more substantive de-risking event than the May 29 denial of the preliminary injunction and expect the company to continue with early works activities as planned," National Bank mining analyst Rabi Nizami said.

The bank expects the shares to rise during construction, citing Stibnite's scale of more than 400,000 gold-equivalent oz. annually, potential $1 billion to $2 billion (C$1.39 billion to 2.77 billion) in annual earnings, the project's strategic importance to the U.S. military for antimony used in weapons, and exploration potential.

The court decision arrives as Perpetua advances toward a final investment decision expected this year, with first gold due in 2029. The Trump administration has fast-tracked Stibnite, and in May the U.S. Export-Import Bank (EXIM) approved a $2.9-billion loan. The country's only domestic reserve of antimony has also received support from the Department of Defense. That backing reflects broader U.S. policy concern over antimony supply: China has dominated global mined antimony production in recent years and imposed export controls on the metal in 2024, moves that pushed Washington to prioritize domestic sources of a mineral used in ammunition, flame retardants, and batteries.

'Outperform' rating

Shares in Perpetua Resources declined 1.8% by mid-Monday in Toronto to C$34.28, valuing the company at C$4.3 billion, as wider markets fell on U.S. strikes against Iran and concerns about a potential interest rate increase. National Bank rates Perpetua "outperform" with a C$55 target.

The court did remand one issue back to the U.S. Fish and Wildlife Service, directing the agency to clarify monitoring and reporting requirements in its Incidental Take Statements. National Bank said the order does not require reconsideration of the agency's underlying findings that the project would not jeopardize protected species. Still, the pending appeal means litigation remains a factor investors will watch as early works proceed.

Construction work is already gathering pace. Components for Stibnite's two autoclaves are being fabricated in Europe after purchase orders were placed earlier this year. Temporary worker housing is in place, about half of the permanent housing units had arrived by Aug. 24, and grading and utility work at the permanent camp site is complete. Initial construction is also underway at the administrative pad and along the Burntlog Route.

$177M third-quarter budget

Perpetua held $574 million in cash at the end of the second quarter, National Bank said. Its third-quarter budget totals $177 million, including $131 million for detailed engineering, $27 million for field operations and early construction, and $7 million for exploration. The spending is expected to occur before the EXIM financing closes and a final investment decision is made later this year.

The company is also continuing a minimum 10,000-metre drill program aimed at adding gold and critical-mineral resources around the permitted mine plan. Four rigs are active and about 5,800 metres have been completed, with assays pending.

National Bank said additional occurrences of scheelite, a tungsten-bearing mineral, have been observed in the Clark Tunnel fault zone, although Perpetua released no new assays with Monday's update.

Recent assays

Earlier this month, Perpetua reported high-grade gold intercepts and a new gold-tungsten discovery along the southeastern edge of the proposed Yellow Pine pit. Drilling also outlined gold mineralization at the adjacent Huckleberry fault zone and returned antimony-tungsten intercepts at Hangar Flats.

The company has said those areas could eventually add to 3.1 million oz. of indicated and inferred gold resources and 99.8 million lb. of antimony resources lying outside the current reserves. Any development beyond the permitted project would require additional regulatory review.

Stibnite is expected to produce an average 463,000 oz. of gold annually during its first four years, according to a December technical report. The project is part of U.S. efforts to establish a domestic antimony supply chain for defence and industrial uses. The site itself carries a legacy of mining dating to the early 20th century, when it supplied antimony and tungsten during wartime, and Perpetua's plan includes remediating damage left by earlier operators.

The project hosts 43.5 million indicated tonnes grading 1.07 grams gold per tonne, 2.12 grams silver and 0.07% antimony, for 1.5 million oz. gold, 3 million oz. silver and 67.1 million lb. antimony, according to the report. Inferred resources add 52.1 million tonnes grading 0.96 gram gold, 1.4 grams silver and 0.03% antimony, containing 1.6 million oz. gold, 2.3 million oz. silver and 32.9 million lb. antimony.