Australian Rare Earths has moved its Koppamurra pilot plant beyond heap leaching, recovering rare earths from about 5,000 litres of leach solution into a Mixed Rare Earth Hydroxide intermediate product. The result provides an early test of the downstream flowsheet, although commercial economics and final product quality remain unproven.
- First approximately 8-tonne column cycle completed
- About 5,000 litres of Pregnant Leach Solution generated
- Rare earths recovered from PLS into MREOH
- MREOH to be refined into customer qualification samples
- Further campaigns planned through December 2026
Koppamurra Pilot Moves Into Product Recovery
Australian Rare Earths Limited (ASX:AR3) has cleared an important technical checkpoint at its Koppamurra rare earths project, moving from demonstrating extraction to producing a concentrated intermediate product. The first heap leach column cycle, using approximately 8 tonnes of ore, generated about 5,000 litres of Pregnant Leach Solution before that liquor was processed through the pilot plant's Mixed Rare Earth Hydroxide precipitation circuit.
Rare Earths Recovered From Leach Solution
AR3 said the precipitation circuit achieved full recovery of rare earths from the processed PLS into MREOH, in line with expectations. That result is significant within the pilot campaign, but its scope matters: the reported full recovery applies to the transfer from leach solution into hydroxide, not necessarily to total recovery from the original ore through the entire flowsheet.
The circuit uses continuous three-stage precipitation reactors, followed by thickening, filtration and washing. These steps are intended to test whether rare earth-bearing solids can be recovered consistently under continuous operating conditions, while also establishing reagent consumption, residence times, water requirements and solid-liquid separation performance.
Pilot Product Will Support Customer Qualification
The MREOH will be further refined into initial Mixed Rare Earth Oxide samples for prospective offtake partners and customer qualification work. AR3 has not disclosed product assays, impurity levels or binding customer agreements in this update, leaving those results as important tests of the intermediate material's commercial relevance.
Further Campaigns To Feed Definitive Feasibility Study
Heap leaching remains underway, with AR3 targeting approximately 28 kilolitres of PLS from multiple pilot campaigns and planning further MREOH precipitation runs through December 2026. The company expects the resulting operating and engineering data to support equipment selection, sizing and design work for its Definitive Feasibility Study.
For now, the announcement marks a positive pilot-scale advance rather than evidence of commercial production. The next meaningful checkpoints are the consistency of later cycles, the quality and impurity profile of the MREOH and MREO samples, and whether the accumulated data can translate into a robust commercial flowsheet.
Bottom Line?
AR3 has demonstrated the first downstream conversion step at pilot scale, but the investment case still depends on repeatability, product quality and the economics that emerge from the remaining campaigns.
Questions in the middle?
- Will later column cycles reproduce the reported leach and precipitation performance?
- What rare earth grades, impurities and recoveries will the first MREO samples show?
- How will the pilot data change the capital and operating assumptions in the Definitive Feasibility Study?