American Rare Earths Reports 3,497 Ppm TREO at Halleck Creek
Initial assays from six holes at the Wyoming site show broad mineralization, supporting the ongoing feasibility study for the Cowboy State Mine.
Key points
- American Rare Earths reported a pooled average grade of 3,497 ppm TREO from the first six holes at Halleck Creek.
- 93% of the 386 assay intervals exceeded the 1,000 ppm TREO cut-off used for the current resource estimate.
- The 18-hole drilling program supports the feasibility study for the Cowboy State Mine, with remaining results due soon.
American Rare Earths Ltd (ASX:ARR, OTCQX:ARRNF) has released initial assay results from its 2026 drilling program at the Halleck Creek Rare Earths Project in Wyoming. The company confirmed broad, near-surface mineralization across the first six holes drilled in the Cowboy State Mine area, providing early data for its current feasibility study.
Certified results from these holes returned a pooled average grade of 3,497 parts per million total rare earth oxides (TREO), with a median of 3,879 ppm TREO. The highest individual sample recorded 9,084 ppm TREO over 3.02 metres in hole HC26-RM051, indicating high-grade zones within the broader mineralized system.
Broad intervals exceed resource cut-off
According to reporting by proactiveinvestors.com, approximately 93% of the 386 geological assay intervals reported exceeded the company’s 1,000 ppm TREO cut-off used for the current Cowboy State Mine resource. This high percentage of intercepts above the cut-off reinforces the broad distribution of mineralization throughout the Red Mountain area.
Several holes returned substantial mineralized sections. Hole HC26-RM056 delivered one of the broadest intervals to date, measuring 191.11 metres at 3,951 ppm TREO starting from 8.84 metres downhole. Other notable intervals included 110.02 metres at 4,221 ppm TREO in HC26-RM055 and 102.63 metres at 3,854 ppm TREO in HC26-RM052.
Feasibility study data expands
The drilling is part of an 18-hole HQ core program designed to support the ongoing feasibility study at Cowboy State Mine. The work specifically targets higher-grade zones near the top of Red Mountain as well as areas around its base to increase geological confidence and support future resource classification.
Chief Executive Officer Mark Wall stated that the first assays represent an encouraging start to the 2026 program, noting that broad continuous mineralization is as important as headline grades. The results provide additional data to support the geological model and ongoing Feasibility Study work.
Remaining assays expected soon
Results from the remaining 12 holes are expected over the coming weeks as laboratory processing and technical review continue. These results will be incorporated into geological modelling, resource classification work, the feasibility study, and the company’s Whole of Property Development Assessment.
Halleck Creek currently hosts a JORC mineral resource of 2.63 billion tonnes at 3,292 ppm TREO, equating to 8.65 million tonnes of contained rare earth oxides. This makes it one of the larger undeveloped rare earth systems in the United States, with the new drilling aimed at refining this estimate.
