Cobra Resources Cuts Reagent Use at Wudinna
Cobra Resources reports that a 40% reduction in ammonium sulphate retained over 90% of key rare earth recoveries in Wudinna lab tests, potentially lowering costs and environmental impact.
Cobra Resources (LSE:COBR) has demonstrated that its Wudinna Rare Earths Project in South Australia can process ore with significantly lower reagent volumes without substantial loss of efficiency. Laboratory tests conducted by the Australian Nuclear Science and Technology Organisation (ANSTO) show that reducing ammonium sulphate concentration by 40% retains approximately 90% of the key rare earth element recoveries achieved with standard industry solutions.
The findings indicate that the company can achieve high recovery rates for magnet and heavy rare earths while using less chemical input. This operational flexibility is designed to reduce supply chain exposure and lower the salinity load introduced to the local aquifer during processing.
Laboratory Tests Show Efficiency Gains
ANSTO completed 24-hour desorption tests on bulk composites from the Boland and Head prospects at Wudinna. At the Boland site, a 0.3 molar solution at pH 3 recovered 70% of neodymium-praseodymium, 67% of dysprosium-terbium, and 67% of heavy rare earth elements. These figures represent 91% to 93% of the recoveries obtained using the industry-standard 0.5 molar concentration.
Similar results were observed at the Head prospect, where the lower concentration recovered 36% neodymium-praseodymium, 52% dysprosium-terbium, and 53% heavy rare earths. This retained 90% to 91% of the recoveries recorded with the stronger solution. The tests utilized saline groundwater sourced directly from the project site, ensuring the results reflect local geological conditions.
Groundwater Testing Reduces Chemical Load
Further testing explored the use of acidified site groundwater without added ammonium sulphate. At Boland, this method recovered 51% neodymium-praseodymium, 46% dysprosium-terbium, and 50% heavy rare earths. Crucially, uranium recovery into the solution dropped from 29% at the standard 0.5 molar concentration to just 5% without the added reagent, indicating a significant reduction in unwanted radionuclide extraction.
Scoping Study Weighs Operational Trade-offs
Managing Director Rupert Verco stated that the next step involves weighing the lower reagent requirements against the slight reduction in recovery rates. The company cautions that these laboratory conditions are not yet commercial operating parameters. The ongoing Scoping Study will assess recovery, reagent consumption, solution chemistry, and overall economics, with further column testing and solution management studies planned to validate these findings.
Cobra Resources expects to announce Wudinna’s maiden mineral resource estimate shortly, followed by further updates to its Scoping Study. The data provides a basis for optimizing the processing plant design to balance cost efficiency with environmental constraints in South Australia.
