Please submit comments through this project-specific comment webpage:
https://stibnitemine.azurewebsites.net/
Interested parties are hereby notified that the U.S. Army Corps of Engineers, Walla Walla District (USACE) has received an application for a Department of the Army (DA) permit for certain work in aquatic resources which may be subject to the regulatory jurisdiction of the USACE, pursuant to Section 404 of the Clean Water Act (33 U.S.C. 1344).
The USACE is requesting comment on the Public Notice and attachments included in the DA permit application package submitted by Perpetua Resource Idaho Inc. (Applicant). The application is for the proposed Stibnite Gold Project, an open pit mine and supporting infrastructure located within Valley County, Idaho.
An Environmental Impact Statement (EIS) is currently being prepared for the proposed Stibnite Gold Project by the U.S. Forest Service, Payette National Forest which is the lead federal agency. The USACE is a cooperating agency.
The following DA permit application materials are included in this Public Notice. These materials have been provided by the applicant, as part of their DA permit application. The information provided by the applicant was prepared to assist the USACE in processing the application for the proposed Stibnite Gold Project. The findings and analysis expressed in the supporting documents are those of the applicant, unless otherwise referenced, and are not those of the USACE.
APPLICANT and AGENT: Perpetua Resources Idaho Inc.; 405 8th St. #201 Boise, Idaho 83702
U.S. ARMY CORPS OF ENGINEERS PROJECT MANAGER: SGP Project Manager, Boise Regulatory Office, 720 E. Park Center Blvd. Suite 245, Boise Idaho 83712
PURPOSE:
Perpetua Resources Idaho, Inc.’s stated purpose is “to develop the Stibnite Gold Project to mine gold, silver, and antimony deposits that, where feasible, would minimize adverse environmental impacts on National Forest Service (NFS) surface resources; and ensure that measures are included that provide for mitigation of environmental impacts and reclamation of the NFS surface disturbance.”
The USACE has determined that the overall project purpose is to mine gold, silver, and antimony from ore deposits associated with the project. This overall project purpose will be used for evaluating practicable alternatives under the 404(b)(1) guidelines.
AQUATIC RESOURCES AND WATERWAYS: The overall project, to include the mine site and offsite components (e.g. access roads, transmission line, logistic facility), intersect with aquatic resources located in the flowing USGS HUC12 Units, listed alphabetically: Beaver Creek, Boulder Creek, Burntlog Creek, Curtis Creek, Ditch Creek- Johnson Creek, Duck Creek- Cascade Reservoir, Headwaters East Fork South Fork Salmon River (EFSFSR), Headwaters Johnson Creek, Lake Fork, Lower Gold Fork River, Lunch Creek-Johnson Creek, No Mans-Creek EFSFSR, Pearsol Creek- North Fork Payette River, Porcupine Creek-Johnson Creek, Riordan Creek, Sheep Creek-Johnson Creek, Six-Bit Creek South Fork Salmon River, Sugar Creek, Tamarack Creek, Trapper Creek-Johnson Creek, Upper Big Creek, Warm Lake Creek.
The mine site is located within the Headwaters EFSFSR HUC 12 Watershed, and includes the following sub watersheds: Blowout Creek, the EFSFSR, Fern Creek, Fiddle Creek, Garnet Creek, Hennessy Creek, Meadow Creek, Midnight Creek, Sugar Creek, and West End Creek.
Stream ordinary high-water mark (OHWM) delineations were conducted concurrently with the wetland delineations by HDR from 2011 to 2016 (HDR 2013, 2014a, 2014b, 2015, 2016a, 2017a) and other areas were assessed in 2018 and 2019 (Tetra Tech 2021c) or will be assessed in the future. The study area for these delineations included major drainages and the hillsides between them for the mine site, primary access road alternatives, the proposed power line corridor, and the proposed logistics center.
Delineated resource types include palustrine emergent, palustrine scrub-shrub, and palustrine forested wetlands and other waters, as well as streams of multiple stream orders and character.
Additional details regarding aquatic resources within the project area can be found in Attachment A: Impact Master Spreadsheet, Section 3 of Attachment C: Applicant Provided 404(b)(1) Analysis, Section 6.1 of Attachment D: Draft Compensatory Mitigation Plan, and in Section 3.11 and 3.12 of the October 2022 Supplement Draft EIS.
The Supplemental Draft EIS is available on the USFS website as follows:
LOCATION: The overall project area boundary to include associated access roads, and off-site facilities are located in Valley County, Idaho. The mine site area boundary is situated approximately 98 miles by air and 146 miles by road northeast of Boise; approximately 44 air miles and 68 miles by road northeast of Cascade; and approximately 10 air miles and 14 miles by road east of the village of Yellow Pine, Idaho.
AUTHORITY: This permit will be issued, issued with special conditions, or denied under the authority of Section 404 of the Clean Water Act (33 U.S.C. 1344). A Department of the Army permit is required for the discharge of dredged or fill material into waters of the United States, including wetlands.
WORK AND ANTCIPATED IMPACTS TO THE AQUATIC ENVIRONMENT: Impacts to aquatic resources would result from development of the mineral resource and includes construction of access and haul roads; construction of supporting infrastructure such as worker housing; open pit mining within 3 pits (Yellow Pine Pit, Hangar Flats Pit, and West End Pit); ore processing; placement of tailings in a tailing storage facility; and placement of development rock. New access to the project site would be provided by a proposed Burntlog Route, which would be a combination of widening the existing Burnt Log Road (Forest Road [FR] 447) and Meadow Creek Lookout Road (FR 51290) and constructing new connecting road segments of approximately 15 miles.
To provide electric power for the project, an existing powerline would require upgrading and a new transmission line from a new proposed Johnson Creek substation to the mine would be constructed. Additional off-site support facilities to be constructed along access corridors would include the Stibnite Gold Logistics Facility and the Burntlog Maintenance Facility.
The proposed project will impact approximately 111,000 linear feet of perennial, intermittent and ephemeral streams, 145 acres of wetlands, and 5 acres of other waters (Yellow Pine Pit Lake). These resources would be adversely impacted by overall mining operations that includes pit excavation, development rock storage facilities, a tailings storage facility, ore processing and support facilities, road construction, and transmission line construction.
Additional details regarding anticipated impacts to aquatic resources can be found in the Attachment A: Impact Master Spreadsheet, Section 3 of Attachment C: Applicant Provided 404(b)(1) Analysis, Section 6.2 of Attachment D: Draft Compensatory Mitigation Plan, and in Section 4.11 and 4.12 of the October 2022 Supplement Draft EIS.
The Supplemental Draft EIS is available on the USFS website as follows:
ADDITIONAL INFORMATION: An EIS is currently being prepared for the Stibnite Gold Project by the U.S. Forest Service Payette National Forest which is the lead federal agency. The USACE is a cooperating agency.
CONSTRUCTION PERIOD: The applicant has requested a permit that would authorize project activities for a period of 41 years (2065). This time period would include discharges related to the development, operation, and reclamation and monitoring of the mine site post closure. Generally, the proposed project would include approximately 3 years for Pre-Production and Construction, 14 years of Mining Operations, and 20+ years of closure activities to include water treatment, and facility decommissioning.
PROPOSED MITIGATION: The applicant has provided a Draft Compensatory Mitigation Plan which proposes the following mitigation measures to avoid, minimize, and compensate for impacts to aquatic resources from activities involving discharges of dredged or fill material. The USACE will evaluate the proposed mitigation measures and independently determine the effectiveness, and sufficiency of the proposed plan.
South Fork Salmon River Subbasin:
Proposed compensatory mitigation for stream and wetland impacts that occur within the South Fork Salmon River Subbasin include permittee-responsible on-site and off-site mitigation.
Permittee-responsible on-site compensatory mitigation will generally occur within reclaimed mine features such as the backfilled Yellow Pine Pit, backfilled Hangar Flat Pit, and on top of the Tailings Storage Facility and Buttress, but also includes enhancement of existing stream reaches within the mine area, and the restoration of Blow-out Creek. The applicant is proposing to establish volitional fish access to available habitat within the mine site as part of their compensatory mitigation proposal.
The applicant proposes to re-establish streams upon reclaimed features and includes design features intended to replicate physical channel processes and aquatic habitat by selectively adding large woody debris and rock structures, eliminating fish passage barriers, creating scour pools, enabling improved sediment sorting, and generally increasing hydraulic and habitat diversity.
Wetland compensatory mitigation sites are generally classified as Valley Margin, Riparian Fringe/Floodplain, Enhancement/Restoration, and Other Wetlands. Riparian Fringe/Floodplain wetlands are generally a component part to re-established stream channels.
The applicant proposes to address temporal impacts to aquatic resources by permittee-responsible off-site mitigation in the Upper Salmon River subbasin. This would occur at the Lemhi Regional Land Trust’s (LRLT) Little Springs Conservation Easement and Restoration Project on the Lemhi River.
North Fork Payette Subbasin.
Impacts within the North Fork Payette Subbasin are generally associated with development of the proposed power transmission line. Impacts within this basin are located within an established service area of an Approved Mitigation Bank.
Permanent wetland impacts/losses are proposed to be compensated by purchasing credits from an approved mitigation bank.
The applicant has proposed off-site mitigation for stream impacts within in the North Fork Payette River subbasin, through the Big Creek Culvert Replacement Project (BCCRP) within the Boise National Forest.
Additional information and details regarding the applicant’s compensatory mitigation proposal can be found in Attachment D: Draft Compensatory Mitigation Proposal.
OTHER ENVIRONMENTAL DOCUMENTS AND DA PERMITS ISSUED TO APPLICANT: DA permits have previously been verified for certain work associated with Stibnite Gold Project, to include culvert installation and water management. DA permits may be requested for future work associated with geophysical investigation/surveying activities for the proposed Burntlog Route.
WATER QUALITY CERTIFICATION: A Department of the Army permit will not be issued until water quality certification has been issued or waived by the Idaho Department of Environmental Quality (IDEQ), as required by Section 401 of the Clean Water Act. The IDEQ has requested a reasonable period of time of 365 days for the IDEQ to either issue, waive or deny the certification request. If water quality certification is not issued, waived or denied by that time, certification will be considered waived.
SECTION 401 (A)(2) NEIGHBORING JURISDICTION: Per 33 CFR 325(b)(1)(i), this public notice serves as notification to the Environmental Protection Agency that the Corps will provide a copy of IDEQ’s water quality certification, if issued, initiating EPA’s 30-day review period under Section 401(a)(2).
OTHER AUTHORIZATIONS: Multiple approvals for the proposed project will be required, to include approvals from the U.S. Forest Service, Idaho Department of Lands, Idaho Department of Environmental Quality, Idaho Department of Water Resources, and Valley County.
CULTURAL RESOURCES: Consultation is currently being conducted with the office of the Idaho State Historic Preservation Officer (SHPO), the Advisory Council for Historic Properties, and other consulting parties. The U.S. Forest Service, Payette National Forest is the lead federal agency, and the USACE is consulting party in the development of Programmatic Agreement for the Stibnite Gold Project. The U.S Forest Service is also consulting with the appropriate Tribal entity or the Tribal Historic Preservation Offices (THPO) for the Nez Perce Tribe, the Shoshone Bannock Tribes and the Shoshone Paiute Tribes, to determine if there are any tribal historic or cultural interests within the project area.
TRIBAL TREATY RIGHTS AND INTERESTS: Federal agencies acknowledge the federal trust responsibility arising from treaties, statues, executive orders and the historical relations between the United States and American Indian Tribes. The federal government has a unique trust relationship with federally recognized American Indian Tribes, including the Nez Perce Tribe, the Shoshone Bannock Tribes, and the Shoshone Paiute Tribes. The Corps has a responsibility and obligation to consider and consult on potential effects to Tribal rights, uses and interests. The USACE further recognizes there is a need for additional and on-going consultation.
ENDANGERED SPECIES: Consultation is currently being conducted with the U.S. Fish and Wildlife Service (USFWS) and the National Marine Fisheries Service (NMFS) for the Stibnite Gold Project. The U.S. Forest Service, Payette National Forest is the lead action agency, and the USACE is a secondary action agency for completing Section 7 Consultation in determining the effect on species designated as endangered or threatened under the Endangered Species Act, or their critical habitat, under the Endangered Species Act of 1973 (87 Stat. 844).
ESSENTIAL FISH HABITAT: The Magnuson-Stevens Fishery Conservation and Management Act, as amended by the Sustainable Fisheries Act of 1996, requires all Federal agencies to consult with the National Marine Fisheries Service (NMFS) on all actions or proposed actions, permitted, funded or undertaken by the agency that may adversely affect Essential Fish Habitat (EFH). EFH species are known to use the project area. Consultation is currently being conducted, and the U.S. Forest Service, Payette National Forest is the lead action agency, and the USACE is a secondary action agency for that consultation.
ENVIRONMENTAL IMPACT STATEMENT: An Environmental Impact Statement (EIS) is currently being prepared for the Stibnite Gold Project. The U.S. Forest Service, Payette National Forest is the lead federal agency for preparation of the EIS and the USACE is a Cooperating Agency. A Supplemental Draft EIS was released for comment on October 28, 2022. The U.S. Forest Service is currently working towards completion of a Final EIS.
The Supplemental Draft EIS is available on the USFS website as follows:
EVALUATION: The decision whether to issue a permit will be based on an evaluation of the probable impact, including cumulative impacts, of the proposed activity on the public interest. This decision will reflect the national concern for both protection and utilization of important resources. The benefit which reasonably may be expected to accrue from the proposal must be balanced against its reasonably foreseeable detriments. All factors which may be relevant to the proposal will be considered, including the cumulative effects thereof; among those are conservation, economics, aesthetics, general environmental concerns, wetlands, historic properties, fish and wildlife values, flood hazards, floodplain values, land use, navigation, shoreline erosion and accretion, recreation, water supply and conservation, water quality, energy needs, safety, food and fiber production, mineral needs, consideration of property ownership and in general, the needs and welfare of the people. In addition, our evaluation will include application of the EPA Guidelines (40 CFR 230) as required by Section 404(b)(1) of the Clean Water Act.
Perpetua Resources Idaho, Inc. has provided an applicant generated evaluation of the proposed Stibnite Gold Project, titled “Clean Water Act Section 404(b)(1) Evaluation for the Stibnite Gold Project” (Attachment C1: Applicant Provided 404(b)(1) Analysis Report). Information from this report may be used by the USACE in processing the application. The findings and analysis expressed in this document are those of the applicant and not those of USACE.
CONSIDERATION OF PUBLIC COMMENTS: The Corps of Engineers is soliciting comments from the general public; Federal, State and local agencies and officials, Tribal entities and other interested parties in order to consider and evaluate the impacts of this proposed activity. Any comments received will be considered by the Corps of Engineers to determine whether to issue, modify, condition or deny a permit for this proposal. To make this decision, comments are used to assess impacts on endangered species, historic properties, water quality, general environmental effects and the other public interest factors listed above. Comments are used in the preparation of an Environmental Impact Statement pursuant to the National Environmental Policy Act. Comments are also used to determine the need for a public hearing and to determine the overall public interest of the proposed activity.
PUBLIC HEARING: Any person may request in writing, within the comment period specified in this notice, that a public hearing be held to consider this application. Requests for a public hearing shall state specific reasons for holding a public hearing.
COMMENT & REVIEW PERIOD: Interested parties are invited to provide comments on the proposed activity through the comment website (Link provided below) or by mailing to the address below. Comments received will become a part of the record and will be considered in the final decision.
Please submit comments through this project-specific comment webpage:
https://stibnitemine.azurewebsites.net/
Alternatively, comments may be mailed to:
U.S. Army Corps of Engineers
Walla Walla District, Regulatory Division
720 E. Park Center Blvd. Suite 245
Boise, Idaho 83712
Comments should be received no later than the comment due date of October 07, 2023, as indicated on this notice to receive consideration.