The Halleck Creek rare earth project in Wyoming has advanced to a new stage of development with the award of a Whole of Property Development Assessment (WPDA), marking a key step toward transitioning from resource definition to integrated, large-scale planning. Work on the assessment is expected to begin in the second quarter of 2026.

The WPDA will consolidate geological, metallurgical, mining, and permitting data across the project’s 8,108-acre land package spanning Albany and Platte Counties, creating a unified framework for future development. Building on the Phase 1 Cowboy State Mine plan, the assessment will establish a long-term roadmap for multi-phase expansion across Red Mountain, Overton Mountain, and Bluegrass, positioning Halleck Creek as a scalable, district-wide operation.

From Single Mine to District-Scale Development

Halleck Creek is regarded as a world-scale rare earth asset, with an estimated 2.63 billion tonnes of ore and approximately 8.64 million tonnes of contained total rare earth oxides, making it one of the largest known deposits of its kind in North America. The Cowboy State Mine alone is projected to operate for around 20 years, supported by a low strip ratio of 0.383, indicating favorable mining conditions.

The newly awarded assessment will evaluate how best to sequence development across the broader property. This includes comparing resource zones based on grade, metallurgical performance, infrastructure access, and permitting considerations, while developing conceptual mine plans at production scales of 5–10 million tonnes per annum (Mtpa). The goal is to optimize resource utilization and extend mine life through coordinated, phased expansion.

Planning Framework for Future Construction

As a planning-level study, the WPDA represents a critical pre-feasibility milestone, providing the technical and economic foundation for future engineering, permitting, and investment decisions. It will also define permitting pathways, particularly for areas located on Bureau of Land Management (BLM) land, and support long-term capital planning across multiple development phases.

The assessment builds on a December 2025 technical breakthrough, where the project successfully produced both mixed rare earth oxalate and mixed rare earth oxide from Halleck Creek ore using an updated processing flowsheet. That achievement demonstrated a viable pathway from raw material to saleable rare earth products, forming the basis for scaling production across the wider project.

Strategic Role in U.S. Critical Minerals Supply

The advancement of Halleck Creek comes amid growing U.S. policy support for domestic critical minerals development, including federal initiatives aimed at accelerating rare earth supply chains for defense and advanced technologies. The project is located in Wyoming, a top-ranked mining jurisdiction globally, further strengthening its position as a long-term domestic supply source.

American Rare Earths, CEO Mark Wall has outlined a strategy focused on completing a Pre-Feasibility Study in 2026, advancing state permitting for the Cowboy State Mine, and scaling production to meet rising demand. The WPDA directly supports this strategy by enabling a phased, district-wide development approach, positioning Halleck Creek as a cornerstone asset in efforts to secure U.S. rare earth independence.

With the assessment expected to run through the end of 2026, the project will move through key stages including data integration, resource comparison, mine planning, and development sequencing — laying the groundwork for eventual construction and long-term production.

Additionally, the advancement of the Halleck Creek project comes as other parts of the U.S. rare earth supply chain move forward. In Ohio, REAlloys Inc. is accelerating its processing expansion by securing supply agreements, advancing engineering for its metallization facility, and locking in federal support. Together, these developments highlight how domestic mining and processing projects are progressing in parallel, as the United States works to establish a fully integrated, China-independent rare earth supply chain ahead of tightening defense procurement rules.

Halleck Creek Rare Earth Project Factsheet

• Location: Wyoming, USA
• Developer: American Rare Earths
• Project Type: Rare earth mining and processing
• Recent Milestone: Award of Whole of Property Development Assessment (April 7, 2026)
• Project Area: 8,108 acres across Albany and Platte Counties
• Resource Size: 2.63 billion tonnes of ore; 8.64 million tonnes TREO
• Phase 1 Asset: Cowboy State Mine (20-year mine life)
• Development Scope: Multi-phase expansion across Red Mountain, Overton Mountain, and Bluegrass
• Planned Throughput: Conceptual scenarios at 5–10 Mtpa
• Current Stage: Pre-feasibility / development planning
• Next Steps: WPDA completion (2026), feasibility studies, permitting, and financing
• Strategic Significance: Supports long-term U.S. rare earth supply chain and critical minerals independence