American Rare Earths Ltd (ASX:ARR, OTCQX:ARRNF) is sharpening the long-term development strategy for its Halleck Creek rare earths project in Wyoming, awarding a whole-of-property development assessment (WPDA) to support district-wide expansion.
The planning-level study, to be undertaken by a major engineering firm, will integrate geological, metallurgical, mining and permitting data across the company’s 8,108-acre landholding and is scheduled to begin in the June quarter of 2026.
Importantly, the WPDA builds on the existing Phase 1 Cowboy State Mine plan, but shifts the focus towards a broader, multi-stage development strategy encompassing Red Mountain, Overton Mountain and Bluegrass — positioning Halleck Creek as a district-scale rare earths hub rather than a single-mine operation.
Scaling a world-class asset
Halleck Creek is already recognised as one of the largest rare earths deposits in North America, with an in-situ mineral resource of around 2.63 billion tonnes. The Cowboy State Mine alone is expected to support a 20-year mine life, underpinned by a low strip ratio.
The WPDA is designed to unlock the full value of that scale by determining how best to sequence development across the broader project area. It will compare resource zones based on grade, metallurgy, infrastructure access and mining characteristics, helping identify priority areas for future expansion phases.
It will also assess conceptual production scenarios in the range of 5 million–10 million tonnes per annum and evaluate pathways to extend mine life and maximise resource utilisation across the entire property.
In parallel, the study will map out permitting pathways, including considerations for federal Bureau of Land Management (BLM) ground, as the company looks to expand beyond its initial state-based development footprint.
Aligning with US supply chain push
The move comes as American Rare Earths continues to align Halleck Creek with growing US policy support for domestic critical minerals.
Recent federal initiatives — including President Donald Trump’s March 2025 executive order and a subsequent Section 232 investigation around critical minerals imports — have underscored rare earths as a national security priority, creating a more supportive backdrop for large-scale domestic projects.
CEO Mark Wall said the WPDA would provide a technical and economic foundation for transforming Halleck Creek into a multi-phase operation capable of supporting US supply chain independence over the long term.
“This work is a critical step in unlocking the full potential of the largest domestic United States rare earth deposit, with some 8.64 million tonnes of contained total rare earth oxide, and advancing our strategy to become a cornerstone of the United States rare earths supply chain,” he said.
The study is also expected to inform long-term capital planning and investment prioritisation, supporting the company’s broader strategy to scale production and potentially pursue a US listing.
Building on recent momentum
The WPDA adds to a steady stream of recent progress at Halleck Creek, as American Rare Earths advances both upstream and downstream aspects of the project.
In recent months, the company has accelerated its pilot plant pathway through key hires and equipment procurement , while also progressing an oxide-to-metal study aimed at strengthening its downstream processing strategy .
These initiatives build on a December 2025 technical breakthrough , where the company successfully produced mixed rare earth oxides from Halleck Creek ore — demonstrating a potential pathway from resource to saleable product and providing key processing inputs for the new development study.
The company is also broadening its US footprint beyond Halleck Creek, including advancing multi-commodity targeting at its La Paz Project in Arizona, highlighting a wider strategy to establish a domestic rare earths platform.
Next steps
The WPDA is expected to run through to the end of 2026, with milestones including data integration, geological synthesis, mine planning scenarios and development sequencing.
For investors, the study represents a shift from single-asset optimisation toward district-scale development — a move that could significantly enhance the long-term value proposition of Halleck Creek as the US looks to secure critical mineral supply chains.
