Montana DEQ Opens Public Comment on Lincoln Area Exploration Environmental Assessment

The Montana Department of Environmental Quality opened public comment on a draft Environmental Assessment for a proposed exploration project near Lincoln after Sentinel Metals, doing business as Great Plains Mining, LLC, submitted plans that would send drill bits up to 2,296 feet into the ground and, by DEQ's own account, intersect the groundwater table.

DEQ issued the notice on March 20, triggering a public comment window that closes April 6, 2026. The draft EA was prepared under the Montana Environmental Policy Act and covers a project that would disturb up to 1.53 acres of ground near Lincoln, all of it on land already disturbed by prior exploration activities. Proposed surface drilling would total up to 14,359 feet across the site.

The agency was direct about the document's legal weight: "The draft EA is not a decision document but rather is a disclosure of the potential impacts from the project." DEQ uses the EA to disclose potential environmental impacts and to share its determination of whether those impacts are significant. The agency noted that if Sentinel's project meets the requirements set forth in Montana law for exploration activities and a performance bond is submitted by Sentinel and approved and held by the state, then DEQ must issue the Exploration License Amendment.

Sentinel would not break ground immediately upon approval of the EA. The company has proposed that exploration operations would commence upon DEQ's acceptance of the required reclamation bond and DEQ's issuance of final approval for the project. No new access roads would be built, though the operation would involve overland travel. Reclamation of any surface disturbance would be required under the license terms.

The anticipated intersection of the groundwater table is among the more consequential technical details in the notice. DEQ conducts groundwater monitoring and assessment in partnership with the Montana Bureau of Mines and Geology and the Montana Department of Agriculture, and the agency's broader water quality work, including 80 total maximum daily load documents and surface water monitoring programs, reflects the regulatory framework within which any groundwater impacts from the Lincoln project would be evaluated.

Comments on the draft EA and the document itself are available through the DEQ website. The April 6 deadline gives Lewis and Clark County residents, water users, and other interested parties roughly two weeks to weigh in before the comment period closes.