PERPETUA RESOURCES CORP.

The Corporation and its subsidiaries have been parties to an ongoing legal proceeding with the Nez Perce Tribe for claimed violations of the CWA allegedly linked to historical mining activities. In August 2019, the Nez Perce Tribe filed suit against the Company in the United States District Court for the District of Idaho. The Company filed an answer generally denying liability and later, the court allowed the Company to amend and file a third-party complaint against the USFS. The Company also filed a separate CWA citizen suit against the USFS alleging that several of the point source discharges, as alleged by the Nez Perce Tribe in its complaint, were occurring on lands owned and controlled by the United States government.

Pursuant to the terms of the voluntary ASAOC executed in January 2021 with the U.S. EPA and the USDA, the Company agreed to dismiss its pending action in the CWA case against the USFS without prejudice. On August 8, 2023, the Company and the Nez Perce Tribe filed the Settlement Agreement to resolve the Tribe’s CWA claims. The parties jointly asked the court to approve the Settlement Agreement and dismiss the case without prejudice. The Settlement Agreement provides for total payments of $5.0 million by Perpetua over a four-year period. This includes $4.0 million of contributions by Perpetua to the Fund to be used by the Nez Perce Tribe to support water quality improvement projects in the South Fork Salmon River watershed and $1.0 million of reimbursements to the Nez Perce Tribe for legal expenses. Following a 45-day review period by the United States Justice Department and the U.S. EPA, the U.S. District Court for the District of Idaho approved the Stipulation for Dismissal and entered a Judgment on October 2, 2023, which resulted in the CWA lawsuit being dismissed without prejudice. Under the Settlement Agreement, the Company anticipates that a dismissal with prejudice will be entered after completion of Perpetua’s required payments. All required payments to date have been made timely pursuant to the terms of the Settlement Agreement. As of September 30, 2025, the current portion of the settlement was $nil with the remaining $2,000,000 classified as long-term.

Certain of the Company’s property interests in the Project site are also subject to existing judicial consent decrees entered into by third parties and various governmental entities with respect to contamination caused by historical mining activities on or near the Project site. These consent decrees, which impose environmental liability and remediation responsibilities on third parties, apply to certain mining claims and mill sites acquired by Perpetua from those third parties. Under the consent decrees, Perpetua is required to grant access to certain Project site areas by regulatory agencies and allow remediation activities to proceed if necessary and to preserve the integrity of previous response actions. Several of the Company’s patented claims in the Hangar Flats and Yellow Pine properties are also subject to a consent decree which requires Perpetua to cooperate with the U.S. EPA and the USFS to implement appropriate response activities.

Additionally, following the USFS’ publication of the ROD and FEIS authorizing the Modified Mine Plan for the Project, claims were filed against the USFS, the USDA and other federal agencies on February 18, 2025 in the United States District Court for the District of Idaho by a number of environmental advocacy groups, including Save the South Fork Salmon, the Idaho Conservation League and other non-governmental organizations, alleging violations of NEPA and other federal laws in the regulatory process. Among other remedies, the claimants seek to vacate the ROD, FEIS, Final Biological Opinions and Project approvals and enjoin any further implementation of the Project. PRII filed a motion to intervene in this lawsuit, which was granted by the district court on April 2, 2025. The District Court issued a scheduling order under which all procedural and dispositive motions are required to be filed by the end of 2025.

On August 29, 2025, the Nez Perce Tribe filed a lawsuit against the USFS, United States Department of Agriculture, and other federal agencies in the United States District Court for the District of Idaho the challenging the USFS ROD and other approvals by the USFS and other federal agencies in connection with the Stibnite Gold Project and alleging violations of NEPA and other federal statutes, regulations, rules, and requirements in the regulatory review and approval process in of the Project. Among other remedies, the Tribe seeks to vacate the USFS ROD, the Final Environmental Impact, Final Biological Opinions, and other approvals and to enjoin any further implementation of the Project. PRII filed a motion to intervene in this lawsuit, which was granted by the District Court on September 4, 2025. A scheduling order has not been entered in this case.

The U.S. District Court on October 2, 2025 issued a general order staying all civil cases listed in the order due to the partial shutdown of the federal government over appropriations for the government. The list included the separate lawsuits filed by the Nez Perce Tribe and by the environmental mentioned above challenging the USFS ROD and other federal agency approvals. This stay does not affect the validity of the USFS ROD or any of the other approvals challenged in either of these lawsuits in connection with the Stibnite Gold Project, and all such approvals remain in effect.

The Company believes the USFS ROD and other federal regulatory processes challenged in the two foregoing federal lawsuits were conducted thoroughly and completely by the relevant federal regulatory agencies. However, there can be no assurance that the Project approvals challenged in those two cases will be upheld upon judicial review.

On March 20, 2025, a putative federal class action lawsuit was filed in the United States District Court for the District of Idaho against the Company and certain of its current officers and directors, on behalf of a proposed class of purchasers of the Company’s common shares during the period from April 17, 2024 to February 13, 2025, inclusive. The claim, captionedBarnes et al. v. Perpetua Resources Corp. et al., Case No. 1:25-cv-00160, alleges that the defendants violated Sections 10(b) and 20(a) of the Exchange Act and Rule 10b-5 promulgated thereunder by making false and/or misleading statements during the period from April 17, 2024 to February 13, 2025 regarding the Company’s expected capital expenditures for the Stibnite Gold Project. The complaint seeks unspecified compensatory damages. The District Court has issued a scheduling order in this case requiring various procedural and substantive motions to be filed by the parties prior to the end of 2025. These deadlines can be modified by the court. The Company filed a motion to dismiss the plaintiffs’ amended complaint on September 30, 2025. The Company believes that the claim is without merit and intends to vigorously defend itself. However, in view of the uncertainties inherent in litigation, the Company does not express a judgment as to the outcome of this litigation.

The Idaho Board of Environmental Quality (“IBEQ”) published an order on May 27, 2025 upholding the air permit to construct (“PTC”) issued for the Project by the Idaho Department of Quality (“IDEQ”) in June 2022 and denying certain petitioners’ appeal from various administrative proceedings with respect to the PTC. The IBEQ on June 27, 2025 denied the petitioners’ motion for reconsideration. Thereafter, the petitioners filed a petition for judicial review in the Idaho state district court for the County of Ada against the IBEQ and IDEQ seeking to set aside the PTC as violative of applicable law and challenging the decisions of the IBEQ upholding the PTC. IDEQ and the IBEQ thereafter moved to dismiss the complaint on procedural grounds, and the court denied that motion and allowed the petitioners to amend their petition. The petitioners’ amended petition, which names the Company as well as IDEQ and the IBEQ as defendants was served on the Company on or about September 23, 2025. The court has entered an order dismissing the Board as a party and requiring all briefs of the parties to be filed by an outside date of January 16, 2025. The Company believes that the IDEQ and the IBEQ properly followed Idaho law in issuing the PTC. However, there can be no assurance that the PTC will be upheld upon judicial review.