Deep Leads Column Leach Tests Yield Over 80% Rare Earth Recovery Including Heavy Elements

Exceptional Extraction Results from Deep Leads

ABx Group Limited (ASX – ABX) has announced highly successful rare earth column leach tests conducted by the Australian Nuclear Science and Technology Organisation (ANSTO) on 26-kilogram bulk samples from its Deep Leads ionic adsorption clay rare earth project in northern Tasmania. The tests demonstrated extraction rates exceeding 80% for total rare earth oxides, including over 70% for the highly sought-after heavy rare earth elements dysprosium and terbium.

These outcomes not only surpass initial expectations but also indicate that heap leaching; a lower-cost, more flexible extraction method; could outperform the conventional tank leaching process. This is a significant development for ABx’s strategy to expedite commercial production while managing capital expenditure.

Heap Leaching – A Game Changer for Rare Earth Extraction

Heap leaching involves stacking ore on an impermeable pad and irrigating it with a leach solution, allowing rare earths to be extracted as the solution percolates downward. This contrasts with tank leaching, where ore is mixed into a slurry and stirred in tanks. The column leach tests simulate heap leaching performance and have confirmed excellent physical stability and uniform percolation of the ore, with minimal bed slumping.

Remarkably, even at a lower ammonium sulfate concentration (0.15 M), the extraction efficiency remained high, suggesting potential for reduced operating costs and environmental impact. This flexibility in processing conditions offers ABx a valuable lever for optimisation as it advances the project.

Market-Ready Product and Customer Interest

Following these promising metallurgical results, ABx plans to engage ANSTO to produce a second mixed rare earth carbonate (MREC) sample from the column leach solutions. The first MREC sample, produced in December, attracted strong interest due to its high heavy rare earth content and low impurities. The new sample is expected to maintain these qualities, reinforcing ABx’s position in the rare earth supply chain, particularly for critical elements essential to clean energy technologies.

Managing Director Dr Mark Cooksey highlighted that the heap leach approach aligns with ABx’s goal of rapid commercialisation, noting the potential for heap leaching to be superior to tank leaching in both cost and operational flexibility.

Next Steps and Strategic Implications

The company will use these results to inform detailed process flowsheet studies with engineering partners, aiming to optimise extraction efficiency and cost-effectiveness. The success of heap leaching at Deep Leads could position ABx as a key supplier of heavy rare earths, elements critical for electric vehicles, wind turbines, and other green technologies.

While these laboratory-scale results are encouraging, further pilot and commercial-scale validation will be essential to confirm economic viability and environmental sustainability at scale. Nonetheless, ABx’s progress marks a meaningful step forward in rare earth extraction technology and supply chain development.