American Rare Earths reports broad mineralisation from first Halleck Creek feasibility holes
American Rare Earths has reported broad, near-surface rare earth mineralisation from the first six holes of its 2026 feasibility drilling program in Wyoming. The results are encouraging for geological continuity, but they cover only part of the program and do not yet represent a new resource estimate.
- 3,497 ppm pooled average TREO across 386 assay intervals
- 93% of intervals exceeded the 1,000 ppm resource cutoff
- 191.11 metres at 3,951 ppm TREO in HC26-RM056
- Peak assay of 9,084 ppm TREO over 3.02 metres
- Results from 12 additional holes remain outstanding
Broad Mineralisation Across Six Red Mountain Holes
American Rare Earths Limited (ASX:ARR) has found the sort of consistency feasibility studies need at its Halleck Creek Rare Earths Project in Wyoming. Certified assays from the first six HQ diamond holes at the Cowboy State Mine returned a pooled average of 3,497 ppm total rare earth oxide, or TREO, across 386 geological intervals, with a median of 3,879 ppm.
About 93% of those intervals, or 358 out of 386, exceeded the company’s 1,000 ppm TREO resource cutoff. The strongest individual sample graded 9,084 ppm TREO over 3.02 metres in hole HC26-RM051, while HC26-RM056 delivered the broadest headline intercept: 191.11 metres at a weighted average of 3,951 ppm TREO.
Results Support the Existing Geological Model
The value of the first batch is less the isolated peak grade than the continuity across all six holes. American Rare Earths said the results are consistent with the existing model of broad, near-surface, allanite-hosted mineralisation at the Red Mountain intrusive complex. That distribution is also consistent with the near-surface mineralisation underpinning the conceptual open-pit approach described in the company’s February 2025 updated scoping study.
The pooled average is a simple, non-length-weighted mean of the 386 individual geological intervals, while the reported mineralised intercepts use sample-length-weighted averages. All intercepts are downhole lengths, and true widths are not known. Those qualifications matter: the results provide geological information for the feasibility study, rather than a direct measure of recoverable tonnes or mine economics.
Feasibility Work Gains More Drilling Data
The 2026 program covers approximately 2,877 metres of HQ core drilling across 18 holes at Red Mountain. Eighteen holes were completed, compared with 19 originally planned, after a mechanical issue with the drill rig during the final stages. Twelve holes targeted higher-grade areas near the top of Red Mountain associated with the proposed early mining sequence, while the remaining holes assessed mineralisation around the mountain’s base.
The core is also being retained for geotechnical, hydrogeological, environmental and metallurgical work. American Rare Earths said the drilling data will feed geological modelling, potential future resource classification, the feasibility study and its Whole of Property Development Assessment. No new Mineral Resource Estimate or Ore Reserve was reported in this announcement.
Twelve Assay Results Still Pending
The next material data point is the balance of the drilling program. Results from 12 additional holes remain subject to laboratory processing, geological interpretation and QA/QC review, with the company saying they will be reported as certified assays become available. The eventual test will be whether the initial continuity holds across the wider dataset and can support changes to resource classification or mine planning.
Bottom Line?
The first six holes reinforce Halleck Creek’s broad mineralisation story, but the feasibility case still depends on the remaining assays, true-width interpretation and the technical work that converts exploration continuity into a mine plan.
Questions in the middle?
- Will the remaining 12 holes reproduce the same broad grade distribution and near-surface continuity?
- Can the expanded dataset support higher-confidence Mineral Resource classification in the proposed early mining areas?
- How will metallurgical, geotechnical and hydrogeological results affect the eventual feasibility study design?
