Restoration and redevelopment company Perpetua Resources Corporation says the US Forest Service (USFS) is in the process of advancing the company’s modified proposed action in the National Environmental Policy Act (Nepa) process.

The authority also updated the permitting schedule for the Stibnite gold project, in Idaho.

Stibnite, sometimes called antimonite, is a sulphide mineral associated with gold. Stibnite is used in the manufacture of matches, fireworks and percussion caps.

The project is designed to use responsible mining to develop a world-class gold mine, restore an abandoned mine site, provide the US with the only domestic source of the critical mineral antimony and contribute to the economic success of Idaho.

Perpetua’s modified proposed action was submitted to the USFS in December 2020 as the "Modified Plan of Restoration and Operations 2" (ModPRO2) and represents refinements to Alternative 2 of the August 2020 draft environmental-impact statement (DEIS).

The refined plan incorporates stakeholder feedback on the DEIS and is designed to reduce the project footprint and improve environmental outcomes.

Modifications include the elimination of waste rock storage areas, overall reductions in mined material, additional pit backfilling and restoration and improvements to water quality and water temperature.

The USFS's decision advances Perpetua’s improved and preferred project design in the Nepa process and sets the project on a clear path to a final permitting decision.

Importantly, the USFS will focus on Perpetua's ModPRO2 and the two identified access routes for the remainder of the Nepa process, eliminating DEIS Alternatives 1 and 3 from further consideration.

To ensure a full analysis of the refined project, the USFS plans to issue a targeted supplemental draft environmental-impact statement (SDEIS) and provide the public and cooperating agencies the opportunity to review and comment on the additional analysis.

"We are pleased the USFS is advancing our proposed action forward and establishing a well-defined path towards a record of decision," says Perpetua CEO Laurel Sayer.

She adds that these actions expressly integrate public input and additional analysis in the process, reduce the project's environmental effects and enhances the company’s restoration and community objectives."

Perpetua is confident the additional analysis in the SDEIS will demonstrate the advantages of ModPRO2 and looks forward to continued engagement with the USFS and all relevant stakeholders as the Nepa process is finalised. 

The project schedule update includes that the SDEIS will be released in the first quarter of 2022; that a final environmental-impact statement and draft record of decision will be published in the fourth quarter of 2022; and that a final record of decision will be issued in the first half of 2023.

The Nepa process is intended to ensure that federal agencies are informed of a proposed action's potential environmental impacts before making final decisions regarding the action.

The rigorous scientific analysis during the preparation of the DEIS and the comments from the public and cooperating agencies provided during the extended 75-day public comment period brought forward concepts that could improve the environmental outcomes of the project.

Perpetua listened to this feedback, evaluated the feasibility and potential benefits of these concepts, and submitted modifications of the proposed plan to the USFS.

The proposed improvements, which reduce the project footprint and are expected to improve water quality conditions at the site during and after project operations, have been incorporated in a 2020 feasibility study. These refinements will now be analysed further in the SDEIS.

"It was important to Perpetua that we listen and act upon feedback provided by community members, tribes, environmental groups and cooperating agencies.

“Incorporating their ideas and additional refinements into the proposed action results in a better project, is the most efficient way to bring it to life longer-term and is the right thing to do for all stakeholders,” states Sayer.