American Rare Earths: Halleck Creek & Wyoming REE Profile

American Rare Earths (ASX: ARR | OTCQX: ARRNF) is advancing the Halleck Creek project in Albany County, Wyoming — the largest known rare earth deposit in the United States by resource tonnage, with a JORC-compliant estimate of 2.63 billion tonnes at 3,292 ppm total rare earth oxides (TREO). The company is pre-production, targeting first output from the Cowboy State Mine between 2029 and 2031, and has secured a non-binding letter of interest from the US Export-Import Bank for up to approximately $456 million in project financing.

American Rare Earths: Company Overview

American Rare Earths Limited is incorporated in Australia and listed on the Australian Securities Exchange (ASX: ARR), with its US operations conducted through the wholly owned subsidiary Wyoming Rare (USA) Inc., headquartered in Lakewood, Colorado. The company’s ADR trades on the OTCQX market under the symbol ARRNF. CEO Mark Wall, who brings more than 25 years of global mining experience, leads a management team focused on advancing Halleck Creek from feasibility through to production.

The company’s stated mission is to establish a domestic US rare earth supply chain — from mine to processed oxide — reducing dependence on Chinese-controlled processing. Halleck Creek sits on Wyoming state land for its initial development phase, avoiding federal NEPA requirements and enabling a projected 2–3 year state permitting timeline. As of the March 2026 quarter, American Rare Earths reported a cash balance of A$24.8 million, supported by a $7.1 million non-dilutive grant from the Wyoming Energy Authority. The company is also pursuing a Nasdaq listing to broaden access to US capital markets.

Halleck Creek: Key Assets & Resource Scale

Halleck Creek is hosted in coarse-grained Precambrian granite in Albany County, Wyoming, covering multiple resource areas including Red Mountain, Bluegrass, Overton Mountain, Sommers Flat, County Line, and Trail Creek. The total JORC mineral resource estimate stands at 2.627 billion tonnes, comprising 1,479 Mt in the measured and indicated category at 3,334 ppm TREO, and 1,147 Mt inferred at 3,239 ppm TREO. Contained rare earth oxides total approximately 8.65 million tonnes across the full deposit.

The resource is weighted toward magnet-critical elements. Neodymium and praseodymium (NdPr) account for approximately 26% of total rare earth oxides — the fraction commercially relevant to neodymium and NdFeB permanent magnet production. The deposit also contains heavy rare earths including dysprosium and terbium, alongside samarium. The resource remains open at depth and along strike, with the company indicating significant future growth potential.

The initial production phase — the Cowboy State Mine — covers only approximately 20% of the broader Halleck Creek deposit. The company projects a mine life extending well beyond 100 years at commercial production rates, making Halleck Creek one of the longest-duration domestic supply opportunities in the global rare earth project pipeline. Full details are available on the United States rare earth country page.

Processing Technology: The Three-Part Halleck Creek Solution

Allanite-hosted rare earth deposits have historically been difficult to process economically — conventional acid leaching creates gel and gypsum fouling that raises costs and reduces recovery. American Rare Earths has developed a three-stage processing approach validated at bench and small pilot scale.

The first stage exploits natural metamictization: radiation damage in the allanite ore fractures the crystal structure, making it significantly easier to leach without high-temperature or high-acid inputs. The second stage — beneficiation — uses gravity and magnetic concentration to reject approximately 94% of non-rare earth waste rock upfront, upgrading feedstock from approximately 0.34% TREO to 3.72% TREO before hydrometallurgical processing begins. The third stage uses magnesium oxide (MgO) for impurity removal, replacing conventional reagents that create problematic gels, without sacrificing rare earth recovery. The preliminary processing flowsheet (released November 2025) runs from crushing and grinding through concentration, leaching, impurity removal, solvent extraction, and precipitation/calcining to produce refined rare earth oxides.

Large-scale metallurgical testing has confirmed the 10-fold concentration upgrade. The company is currently working toward offtake and product validation in parallel with its 2026 drilling programme.

Latest Developments & Project Timeline

American Rare Earths commenced its 2026 exploration drilling campaign at Halleck Creek in May 2026. The programme comprises 19 holes across the Red Mountain area of the Cowboy State Mine, designed to generate the resource and geotechnical data required for a Definitive Feasibility Study (DFS). The company expects to conclude the maiden drilling campaign by mid-July 2026.

The Pre-Feasibility Study (PFS) is targeted for completion in late Q3 2026. The project’s published development pathway then targets industrial permitting and financing through 2027, facility construction from 2029/2030, and operational startup from 2030/2031. That timeline is described by the company as under review, reflecting typical iterative adjustments as feasibility work advances.

American Rare Earths has also commissioned a separate oxide-to-metal study for heavy rare earths, exploring downstream processing of dysprosium and terbium oxides — elements where US domestic supply is effectively zero. For context on where Halleck Creek ranks among competing US projects, see the top 10 rare earth mining companies in the USA and the top 10 North America rare earth projects.

American Rare Earths in the Global REE Market

American Rare Earths occupies a specific niche within the Western supply chain: a large-tonnage, low-grade ionic deposit on US federal-free land with a technically differentiated processing approach. Its competitive positioning rests on resource scale — at 2.63 billion tonnes, Halleck Creek exceeds the resource base of most other US domestic projects by a substantial margin — rather than on near-term production capacity or processing throughput.

The company is not a producer and generates no revenue from mining operations. Its value proposition is strategic: providing the United States with a domestic rare earth resource capable of supplying magnet-grade NdPr oxide and heavy rare earth elements for decades, without reliance on Chinese refining. The US EXIM Bank’s non-binding LOI for up to $456 million — subject to PFS outcomes — signals institutional support for that thesis, though it carries no commitment to fund. USGS Rare Earths Statistics data confirms the US currently produces no separated rare earth oxides domestically outside MP Materials’ Mountain Pass facility.

American Rare Earths — Company Snapshot

This article is for informational purposes only and does not constitute investment advice. Project timelines and financing figures are subject to revision. Prices and market data are subject to change without notice.