Accepting comments from February 19, 2026, through April 20, 2026.
The Idaho Department of Environmental Quality (DEQ) is seeking comment on a draft cyanidation permit modification for the Stibnite Gold Project (SGP).
Perpetua Resources Idaho, Inc. (referred to as Perpetua Resources) is requesting a modification to their permit to construct and operate a cyanidation facility as part of the SGP per the “Rules for Ore Processing by Cyanidation” (IDAPA 58.01.13).
Perpetua Resources is the operator of the SGP, a proposed gold mine located in Valley County, approximately 12 miles east of Yellow Pine, Idaho. The SGP is located on private and public lands within the Boise and Payette National Forests. Perpetua Resources has 29,827 acres of mining claims comprised of both unpatented (28,477 acres) and patented (1,350 acres) claims. The mine is also located within the historical Stibnite Mining District, an area impacted by previous mining activities including underground mine workings, rock dumps, tailings deposits, and open pits, including the Yellow Pine Pit.
Following review of the complete permit modification application, DEQ determined the application for the grinding and flotation phase of the ore processing facility is technically complete, per Idaho Code § 39-118A. Therefore, DEQ prepared a draft modified cyanidation permit, which establishes the procedures and requirements to construct that component of the cyanidation facility. The draft permit would ensure that cyanidation pollutants generated in ore processing utilizing cyanide are safely contained, controlled, and treated so that they do not impair beneficial use of waters or degrade waters.
DEQ will host a public meeting for the draft permit at DEQ’s State Office (1410 N. Hilton Street, Boise, Idaho) and via Microsoft Teams on March 2, 2026, from 11 a.m. to 1 p.m. Mountain Time (MST). The draft permit and fact sheet are available for review at DEQ’s State Office, Boise Regional Office (1445 N. Orchard Street, Boise, Idaho), and on DEQ’s Public Comment Opportunities web page. Written comments will be accepted through April 20, 2026, until 5 pm MST. Comments may be submitted via DEQ’s website or by mail or email to:
Adam McMahon
Cyanidation Program Manager
Idaho Department of Environmental Quality
1410 N. Hilton St.
Boise, ID 83706
adam.mcmahon@deq.idaho.gov
Related Documents
Permit Modification and Related Materials
Accessibility Services: The Idaho Department of Environmental Quality will provide reasonable language access services and/or disability services for documents at no charge. To request an accommodation under Title VI of the Civil Rights Act of 1964 or Americans with Disabilities Act, contact DEQ’s nondiscrimination coordinator at (208) 373-0271 or accessibility@deq.idaho.gov. Para obtener información en español, visite https://www.deq.idaho.gov/about-us/accessibility/.
Official Government Website
DEQ seeks comment on draft cyanidation permit modification for Perpetua Resources Idaho, Inc.
Accepting comments from February 19, 2026, through April 20, 2026.
The Idaho Department of Environmental Quality (DEQ) is seeking comment on a draft cyanidation permit modification for the Stibnite Gold Project (SGP).
Perpetua Resources Idaho, Inc. (referred to as Perpetua Resources) is requesting a modification to their permit to construct and operate a cyanidation facility as part of the SGP per the “Rules for Ore Processing by Cyanidation” (IDAPA 58.01.13).
Perpetua Resources is the operator of the SGP, a proposed gold mine located in Valley County, approximately 12 miles east of Yellow Pine, Idaho. The SGP is located on private and public lands within the Boise and Payette National Forests. Perpetua Resources has 29,827 acres of mining claims comprised of both unpatented (28,477 acres) and patented (1,350 acres) claims. The mine is also located within the historical Stibnite Mining District, an area impacted by previous mining activities including underground mine workings, rock dumps, tailings deposits, and open pits, including the Yellow Pine Pit.
Following review of the complete permit modification application, DEQ determined the application for the grinding and flotation phase of the ore processing facility is technically complete, per Idaho Code § 39-118A. Therefore, DEQ prepared a draft modified cyanidation permit, which establishes the procedures and requirements to construct that component of the cyanidation facility. The draft permit would ensure that cyanidation pollutants generated in ore processing utilizing cyanide are safely contained, controlled, and treated so that they do not impair beneficial use of waters or degrade waters.
DEQ will host a public meeting for the draft permit at DEQ’s State Office (1410 N. Hilton Street, Boise, Idaho) and via Microsoft Teams on March 2, 2026, from 11 a.m. to 1 p.m. Mountain Time (MST). The draft permit and fact sheet are available for review at DEQ’s State Office, Boise Regional Office (1445 N. Orchard Street, Boise, Idaho), and on DEQ’s Public Comment Opportunities web page. Written comments will be accepted through April 20, 2026, until 5 pm MST. Comments may be submitted via DEQ’s website or by mail or email to:
Adam McMahon
Cyanidation Program Manager
Idaho Department of Environmental Quality
1410 N. Hilton St.
Boise, ID 83706
adam.mcmahon@deq.idaho.gov
Related Documents
Permit Modification and Related Materials
Accessibility Services: The Idaho Department of Environmental Quality will provide reasonable language access services and/or disability services for documents at no charge. To request an accommodation under Title VI of the Civil Rights Act of 1964 or Americans with Disabilities Act, contact DEQ’s nondiscrimination coordinator at (208) 373-0271 or accessibility@deq.idaho.gov. Para obtener información en español, visite https://www.deq.idaho.gov/about-us/accessibility/.
Public Comment Form