ABx Group (ASX: ABX) has delivered strong results from rare earth column leach tests conducted on bulk samples from its Deep Leads project in northern Tasmania.
The Australian Nuclear Science and Technology Organisation (ANSTO) undertook the metallurgical work in December 2025 as part of ongoing studies assessing potential processing pathways for the project.
The results demonstrated high recoveries across total and heavy rare earth (HRE) elements, exceeding the company’s expectations.
ABx said the outcomes support the technical feasibility of heap leaching as a potential development option for the Deep Leads ionic adsorption clay rare earth project.
Column Leach Test Outcomes
The test work comprised two column leach tests on 26-kilogram bulk samples sourced from trial pit DLP002 within the Deep Leads resource.
Both tests achieved more than 80 per cent extraction of total rare earths, confirming strong overall recoveries from the clay-hosted mineralisation.
Recoveries of the high-value HRE dysprosium and terbium exceeded 70 per cent, reinforcing the quality of the rare earth assemblage within the deposit.
The results confirm that high extraction levels can be achieved using multiple flowsheet configurations, providing flexibility for future optimisation.
Industry-Standard Simulations
The column leach tests were conducted as industry-standard simulations of heap leaching to compare performance against previously completed tank leach test work.
The results indicate heap leaching could match or potentially outperform tank leaching, while offering lower capital intensity and greater operational flexibility.
“ABx is investigating heap leaching because it is potentially lower capital cost and more flexible than tank leaching, which is aligned with our strategy to enter commercial production as soon as possible,” chief executive officer Dr Mark Cooksley said.
Heap leaching requires less fixed infrastructure, and may therefore offer advantages in construction timelines and scalability.
High HRE with Low Impurities
The leach solutions produced during the tests exhibited a high heavy rare earth content with low impurity levels, which is considered favourable for downstream processing.
ABx said the aluminium to total rare earth ratio in the solution remained low, supporting the potential production of a high-quality mixed rare earth carbonate product.
The company plans to engage ANSTO to produce a second mixed rare earth carbonate sample from the column leach solutions for marketing purposes.
The test results will be incorporated into ongoing process flowsheet studies being conducted with engineering partners to guide future development decisions.
