Perpetua reaches final settlement to resolve Clean Water Act lawsuit

Stibnite Gold project pit. Image from Perpetua Resources.

Perpetua Resources (Nasdaq: PPTA) (TSX: PPTA) announced Wednesday that it has reached a final settlement with Nez Perce Tribe and filed their agreement with the US District Court for Idaho. The parties previously reached an agreement in principle in mid-June 2023.

The agreement, once approved, would resolved a Clean Water Act lawsuit brought by the Tribe in 2019 over alleged pollution discharges into the headwaters of the East Fork South Fork (EFSF) Salmon River from historic mining activities within the Stibnite mining site in central Idaho.

The agreement provides for total payments of $5 million by Perpetua over a four-year period, which includes $4 million of contributions by Perpetua to a South Fork Salmon Water Quality Enhancement Fund, to be used by the Tribe to support water quality improvement projects in the South Fork Salmon River watershed. The remaining $1 million will be reimbursements to the Tribe for its legal expenses.

According to Perpetua, the water quality improvement projects will be coordinated with the US Environmental Protection Agency and the US Forest Service, and will require additional data collection to choose and define the projects.

Following the 45-day review period, the Tribe and the company will request the court to approve the stipulation for dismissal and agreement, thus ending a dispute resolution process that was initiated in February 2021.

Perpetua’s flagship Stibnite project represents one of the largest and highest-grade open-pit gold mines in the US. According to a January 2021 feasibility study, the deposit has total proven and probable mineral reserves of 104.6 million tonnes grading 1.43 grams per tonne gold.

The company is currently focused on the legacy cleanup of the historic mine site. So far, it has successfully degraded the levels of arsenic and antimony from millions of tonnes of unconstrained tailings and other mine waste left behind by previous operators over the last 100 years.

Perpetua has permission from both the US EPA and the US Department of Agriculture to conduct time critical early action cleanup activities.