Mine profile
Sheep Creek: location, owner, status and timeline (2026)
Exploration Montana
Sheep Creek, in the West Fork Ranger District of the Bitterroot National Forest in Ravalli County, Montana, south of Darby, is a carbonatite rare earth prospect that private company US Critical Materials explores under about 334 unpatented claims. The Forest Service is reviewing a revised exploration plan, with a decision estimated for July 2027.
Verified through Oct 1, 2026
Status and timeline Report a correction All US rare earth mines
Where is Sheep Creek?
Sheep Creek is in the West Fork Ranger District of the Bitterroot National Forest, south of Darby in Ravalli County, Montana, near the headwaters of the West Fork of the Bitterroot River and the Montana and Idaho divide. It is not a town or a farm site.
The proposal area sits at the confluence of Sheep Creek and the West Fork of the Bitterroot River. The December 2025 draft plan covered 336 unpatented lode claims over 7,277 acres, and the company describes about 334 claims over roughly 11 square miles.
The name is shared with many other places called Sheep Creek, so searches should include "Bitterroot" or "Ravalli County".
Who owns Sheep Creek?
US Critical Materials, a private company, holds the Sheep Creek claims and is the proponent of the exploration plan before the Forest Service. The land itself is National Forest, so the company holds mining claims rather than the surface.
The company has described itself as based in Salt Lake City and, per this directory's research, moved its headquarters to Darby, Montana in June 2026. A 2025 profile named James Hedrick as president and Harvey Kaye as executive director. See US Critical Materials: what it does, projects, funding and status.
In April 2026 REalloys signed a non-binding memorandum of understanding with US Critical Materials under which it plans to obtain up to 10% of Sheep Creek production, with the aim of agreeing a definitive offtake within 12 months.
What is the status and timeline of Sheep Creek?
Sheep Creek is in "Exploration": it has no resource estimate and no permit, and the Forest Service is reviewing a revised plan the company submitted on Jun 12, 2026. Public comment opened Aug 14, 2026, and the agency estimates a decision in Jul 2027.
- Feb 2025
US Critical Materials reports confirmation of high rare earth and gallium grades at Sheep Creek.
- Dec 5, 2025
The Bitterroot National Forest receives a draft initial plan of operations.
- Dec 2025 to Jan 2026
Public meetings draw hundreds; Ravalli County commissioners and conservation groups voice opposition.
- Early 2026
The company rescinds the draft after the criticism and says it will file a reduced plan.
- Apr 2, 2026
REalloys and US Critical Materials sign a non-binding MoU for up to 10% of Sheep Creek production.
- Jun 12, 2026
The company submits a revised, reduced plan of operations. A Phase II research agreement with Idaho National Laboratory for a pilot plant is reported the same month.
- Aug 14, 2026
The Forest Service opens public comment; comments are most effective by Sept 13.
Next milestones
- Feb 2027
The Idaho National Laboratory research agreement runs through this date.
- Jul 2027
The Forest Service estimates a decision on the plan.
- Oct 2027
Implementation of the approved work is estimated to begin.
What rare earths does Sheep Creek hold?
Sheep Creek holds carbonatite-hosted rare earths that the company reports at grades around 9% total rare earth elements, including neodymium, praseodymium, dysprosium, terbium and yttrium, plus gallium averaging over 300 ppm. These are sample results, and no resource has been estimated.
Company materials say the deposit lacks the radioactive contaminants that complicate many rare earth ores. Sheep Creek is among the highest-grade reported US prospects but the least defined by drilling, which is why it sits in the exploration stage next to Lemhi Pass and Diamond Creek across the Idaho border.
| Item | Reported figure | Basis |
|---|---|---|
| Total rare earth elements | Around 9% (89,932 ppm) | Company-reported sampling |
| Neodymium plus praseodymium | About 2.4% | Company-reported sampling |
| Gallium | Averages over 300 ppm | Company-reported, per the REalloys announcement |
| Higher figure in the literature | About 20% total rare earths with 3.3% NdPr | Cited in the OSTI review; the sample basis is not stated there |
| Resource estimate | None | Exploration stage |
Grades from selected samples are not a resource. A resource estimate needs systematic drilling and a qualified person's report, and none has been published for Sheep Creek.
What work is proposed at Sheep Creek?
US Critical Materials proposes to sample or drill at four locations near the Sheep Creek and West Fork confluence, two of them at old adits, and to collect about 3,000 tons of bulk rock over two field seasons, flown out by helicopter. The Forest Service calls it an exploration proposal.
The first plan, a draft received on Dec 5, 2025, drew heavy criticism. Conservation groups said it looked closer to a mine plan than to exploration. After a wave of opposition the company rescinded it and later submitted a reduced scope on Jun 12, 2026, which the Forest Service released for review.
At the adits the company would enlarge the openings, with bulk sampling at one site and drilling at the other, using controlled blasting inside the tunnels. A Daily Montanan headline reported that the update calls for 2,200 helicopter flights in the first season.
The company has also signed a research agreement with Idaho National Laboratory for a pilot-scale processing plant. It was extended through February 2027, and the sources checked give no site or start date for the plant.
What permits and community issues affect Sheep Creek?
Sheep Creek needs Forest Service approval of its plan of operations and compliance with Montana's Metal Mine Reclamation Act, which the state's environmental agency said applies. Residents, county commissioners and conservation groups oppose it over water, fish and the Bitterroot's headwaters.
Public meetings drew large crowds: more than 500 people filled a Hamilton auditorium and about 1,000 attended a Ravalli County commissioners meeting at the fairgrounds. The commissioners voted unanimously to ask the congressional delegation to remove the project from the FAST-41 list, citing a lack of public engagement.
The project remains on the FAST-41 transparency list in the sources checked. The Forest Service estimates scoping in Aug 2026, a decision in Jul 2027 and implementation in Oct 2027. The comment period opened Aug 14, and comments were most effective if submitted by Sept 13. Reports differ on whether the agency will first test for a categorical exclusion or prepare an environmental assessment.
Opponents point to the West Fork of the Bitterroot as trout water and as the source of irrigation for local agriculture. The company says it is taking the concerns into account and will not rush.
What government support has Sheep Creek received?
Sheep Creek has no grant or loan in the sources checked. It benefits from a federal research agreement with Idaho National Laboratory and from inclusion on the FAST-41 transparency list, which is a process listing and not funding.
| Agency and instrument | Amount | When | Status |
|---|---|---|---|
| Idaho National Laboratory (Department of Energy)Phase II cooperative research agreement (pilot processing plant). A research agreement, not a grant to the company | Not stated | Extended through Feb 2027 | Closed |
| Federal Permitting Council (FAST-41)Transparency project listing. Ravalli County commissioners asked for removal from the list | Process, not money | 2025 to 2026 | Closed |
Federal research agreements usually share costs and do not pay for mining. See FAST-41 permitting and US rare earth projects.
Questions about Sheep Creek
Where is the Sheep Creek rare earth project?
Sheep Creek is in the West Fork Ranger District of the Bitterroot National Forest, south of Darby in Ravalli County, Montana, near the headwaters of the West Fork of the Bitterroot River.
Who owns Sheep Creek?
US Critical Materials, a private company, holds the claims and is the proponent of the exploration plan. The land is National Forest, so the company holds about 334 unpatented mining claims.
Is Sheep Creek an operating mine?
No. Sheep Creek is an exploration prospect with no resource estimate or approved plan. The Forest Service is reviewing a reduced exploration plan submitted Jun 12, 2026, with a decision estimated for Jul 2027.
How high is the grade at Sheep Creek?
Company-reported sampling shows around 9% total rare earth elements and about 2.4% neodymium plus praseodymium. These are sample results from an exploration project and not a resource estimate.
Why do locals oppose the Sheep Creek project?
Residents and conservation groups cite risks to water, fish and agriculture in the Bitterroot headwaters and say the first plan read like a mine plan. Hundreds attended public meetings, and Ravalli County commissioners asked to drop it from the FAST-41 list.
Has Sheep Creek been approved?
No. The Forest Service opened public comment on Aug 14, 2026 and estimates a decision in Jul 2027. The state also said Montana's Metal Mine Reclamation Act applies to the work.
Sources and verification
Each profile lists its sources, a confidence grade and a verification date. Order of authority: official records (SEC filings, agency documents), company documents and technical reports, research papers, then independent press. Syndicated copies and reference works are labeled and are never the only source for a number. Company-reported figures are labeled as such, and non-binding deals are labeled "letter of intent" or "conditional".
- OSTI review, Minerals Engineering 249 (Kashyap et al., 2026) Research paper
- Forest Service: Sheep Creek Rare Earth Exploration Proposal Official record
- Mining Technology: REalloys and US Critical Materials sign a Sheep Creek MoU (Apr 2026) Independent press
- KPAX: mining company to revise and reduce its Sheep Creek draft plan Independent press
- KXLF: Bitterroot National Forest launches environmental review of Sheep Creek Independent press
- KPAX: Forest Service takes public comment on Sheep Creek Independent press
- Daily Montanan: Sheep Creek update calls for 2,200 helicopter flights Independent press
- Mining.com: US Critical Materials and Idaho National Laboratory research agreement Independent press
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