American Rare Earths Unlocks Major Metallurgical Milestone at Halleck Creek

American Rare Earths (ASX: ARR) has unveiled a significant technical breakthrough at its Halleck Creek Rare Earths Project in Wyoming, with leach test results showing high rare earth recoveries and notably low impurity levels—positioning the project for cost-efficient downstream processing and stronger economic viability.

Highlights:

• Light Rare Earth Leach Recoveries:

  • Praseodymium (Pr): 85%

  • Neodymium (Nd): 84%

• Heavy Rare Earth Leach Recoveries:

  • Terbium (Tb): 52%

  • Dysprosium (Dy): 46%

• Impurity Reduction:

  • Iron and aluminium levels post-leach are approximately 5x and 2.9x lower, respectively, than previous tests.

• Preferred Method Confirmed:
  Atmospheric tank leaching was selected over acid-bake and counter-current methods due to its superior efficiency, lower cost, and reduced environmental footprint.

De-risking the Project: Paving the Way for PFS

The metallurgical testing, conducted by SGS in Ontario, included 25 leach tests using sulfuric acid. Results confirmed optimal leach conditions and solidified the design pathway for the project's upcoming Pre-Feasibility Study (PFS). Atmospheric tank leaching not only offers high recoveries for valuable rare earth elements like Nd and Pr but also limits impurity extraction—resulting in cleaner, lower-cost downstream processing.

According to ARR, these leaching outcomes represent a significant technical de-risking step. The preferred leach setup (referred to as AL16) includes:

• 80% unaltered concentrate produced via spiral separation and magnetic sorting (IRMS)

• 20% fines upgraded via WHIMS

• Regrinding to -53 µm for optimal liberation

Superior Leach Results with Lower Acid Consumption

Compared to prior scoping study tests, the current methods improved impurity extraction metrics across the board:

• Iron: Reduced by 80%

• Aluminium: Reduced by 65%

• Zinc and Manganese: Reduced by over 75%

These improvements suggest significant potential for reduced reagent use in impurity removal—leading to both capital and operational cost savings.

Technical Advantages and Strategic Significance

The Halleck Creek project’s success in confirming effective atmospheric leaching furthers its strategic advantage as a U.S.-based rare earth supply source. Unlike acid-bake methods used in other jurisdictions, ARR's chosen path avoids high-temperature, corrosive processing, while maintaining strong recovery rates for critical magnet materials.

Additional testing showed that altered (weathered) ore performed nearly as well as unaltered material—suggesting flexibility in ore blending and robustness of the leaching process.

Next Steps

SGS is now undertaking impurity removal trials, the next crucial phase in flow-sheet development. These steps will feed directly into engineering work and pilot-scale processing ahead of the PFS.

ARR Managing Director Chris Gibbs has previously described Halleck Creek as “one of the most significant rare earth assets in the U.S.,” and these results move it closer to becoming a domestic source of vital magnet materials needed for clean energy and defense technologies.

For more information, visit: www.americanree.com