Montana Department of Environmental Quality About Us Permitting & Operator Assistance Public Participation

WMRD, AML | Draft Environmental Assessment Sunset Mine | Comment Period Ends July 07, 2026

  • June 08 2026

General Reasonable Necessity Statement

The Sunset Mine Drainage Project responds to emergency groundwater flooding events that occurred in July 2024, which resulted in significant flooding at 221/217 Grant Avenue South. These events prompted the rapid installation of a temporary dewatering system to mitigate rising hydrostatic pressure believed to be caused by the failure of a historic abandoned mine drainage pipeline. This EA provides a comprehensive analysis of the potential environmental, cultural, and socioeconomic consequences associated with implementing a permanent dewatering solution and related infrastructure. It includes a comparative analysis of alternatives, including the No Action Alternative, and is intended to inform agency decision-making while ensuring full compliance with applicable environmental statutes and permitting requirements.

Draft Sunset Mine Environmental Assessment

Send/Submit Comments To:

Contact

DEQ AML Program

Attn: John Babcock

(406) 444-6473

DEQMontanaAML@mt.gov


Tags: MEPA, Public Comment and AML