The Montana Department of Environmental Quality has approved an Exploration License Amendment for Sentinel Metals and issued a final Environmental Assessment for the Columbia Gold Project, located near Lincoln in Lewis and Clark County.
DEQ accepted public comment on the draft EA from March 20 through April 13, 2026, drawing significant public interest. The agency received 8,736 comments from 1,713 individuals and corporations during the comment period. Reviewers identified 26 broad themes among the submissions and addressed them as substantive comments — those deemed relevant, fact-based and specific enough to offer meaningful insight or analysis on the proposed project. All comments were reviewed and responses were incorporated into the final EA.
Sentinel Metals posted a performance reclamation bond on May 26, 2026. DEQ accepted the bond on June 3 and issued an Approval to Proceed on June 5.
The approved Exploration License Amendment authorizes the collection of subsurface geological information through core drilling to characterize mineralization at the project site, building on prior exploration conducted in 2016. The activities are limited to up to 1.53 acres of surface disturbance on ground previously disturbed by prior exploration work. Proposed drilling is authorized to total up to 14,359 feet across multiple drill holes, with a maximum depth of 2,296 feet, and is anticipated to intersect the groundwater table. No new access roads are authorized, though overland travel may occur during operations. Full reclamation of any surface disturbance is required upon completion.
In the final EA, DEQ disclosed potential environmental impacts from the project and determined that the proposed exploration meets the requirements of the Metal Mine Reclamation Act. The agency noted that the final EA is not itself a decision document but serves to disclose potential impacts associated with the project.