Montana Department of Environmental Quality Publishes Final Environmental Impact Statement for the East Boulder Mine Expansion
HELENA—The Montana Department of Environmental Quality (DEQ) and the Custer Gallatin National Forest (Forest Service) have prepared a final joint Environmental Impact Statement (EIS) to analyze the potential impacts of a proposed amendment (Amendment 004) to the East Boulder Mine Plan of Operations and Operating Permit No. 00149. The East Boulder Mine is operated by Stillwater Mining Company (SMC), a subsidiary of Sibanye-Stillwater. Since 2002, SMC has produced platinum group metals from the East Boulder Mine in Sweet Grass County, Mont.
In 2022, SMC applied to DEQ to amend its hard rock mining operating permit to allow for expansion of the East Boulder Mine. The amendment would allow construction and operation of a new tailings storage facility and waste rock storage area. Construction of these facilities would provide SMC with the tailings and waste rock storage capacity needed to continue to mine for approximately 11 to 14 years, based on current production rates. State and Federal agencies collaborated to analyze and disclose the potential impacts of the project and inform decision making on the proposed expansion. The EIS was prepared in compliance with the Montana Environmental Policy Act and the National Environmental Policy Act. A draft EIS was published for public comment in June 2023, and substantive comments are addressed in the final EIS.
In the final EIS, the agencies identify Alternative 3, which was revised in response to public comments, as the preferred alternative. Alternative 3 meets the intent of the proposed action and incorporates additional design elements, including storm water channels and geomorphic or landform architecture design at the mine’s Lewis Gulch Tailings Storage Facility and Dry Fork Waste Rock Storage Area. The stormwater channels would be designed to withstand a 1-in-200 year, 24-hour precipitation event.
Each agency will document a selected alternative for the project in a Record of Decision, which will be issued at a future date. Pursuant to the Administrative Rules of Montana 17.4.620(5), DEQ must not issue a Record of Decision until 15 days have expired from the date of transmittal of the Final Environmental Impact Statement to the Governor and the Environmental Quality Council. Issuance of the Record of Decision starts a 90-day period in which the applicant and other parties may appeal DEQ’s final EIS.
To read the final EIS, visit the project webpage at: https://www.fs.usda.gov/project/?project=61385.
Tags: MEPA, Press Release and Hard Rock