Cobra Resources Reports Flexible REE Recovery Options

Cobra Resources PLC has published new metallurgical test results from its Wudinna Rare Earths Project in South Australia. The company reports that its ore can be processed effectively using lower concentrations of ammonium sulphate, a key reagent in hydrometallurgical recovery. These findings suggest a potential reduction in input costs and supply chain risks for the upcoming development phase.

The data was generated by the Australian Nuclear Science and Technology Organisation (ANSTO) using bulk composite samples from the Boland and Head prospects. By demonstrating operational flexibility across different lixiviant strengths and pH levels, Cobra aims to optimize the balance between recovery rates and reagent consumption. This approach is intended to support the economic modeling required for the project's Scoping Study.

Recovery Rates Remain High at Lower Concentrations

Tests on the Boland composite sample showed that a 0.3 molar ammonium sulphate solution at pH 3 recovered 70% of neodymium and praseodymium. This figure was only slightly lower than the 77% recovery achieved with the industry-standard 0.5 molar solution. For dysprosium and terbium, recoveries were 67% at the lower concentration compared to 74% at the higher level, indicating that significant magnet rare earth elements can still be extracted with reduced reagent usage.

The Head composite sample exhibited different behavior, with 0.3 molar solutions recovering 36% of neodymium and praseodymium versus 40% at 0.5 molar. Dysprosium and terbium recoveries were 52% and 57% respectively under these conditions. These variations highlight the need for site-specific engineering assessments to determine the optimal operating parameters for each deposit within the Wudinna project.

Reduced Reagent Use Lowers Environmental Load

A significant finding of the ANSTO tests is the reduced mobilization of uranium at lower reagent molarities. On the Boland composite, reducing the ammonium sulphate concentration from 0.5 molar to zero decreased uranium recovery from 29% to 5%. This reduction is critical for minimizing the salinity load introduced to the confined aquifer, thereby lowering the environmental footprint of the processing plant.

Cobra Resources notes that using acidified site groundwater without added ammonium sulphate recovered approximately 50% of key magnet and heavy rare earth elements. While lower than the reagent-based methods, this option eliminates the need for external reagent supply entirely. The company plans to evaluate these trade-offs to define commercial operating parameters that balance cost, supply security, and environmental compliance.

Scoping Study Will Define Economic Parameters

The company stated that these results provide a range of potential operating conditions for further engineering trade-off studies. Managing Director Rupert Verco emphasized that recovery rates cannot be assessed in isolation from cost and environmental factors. The Scoping Study will integrate data on reagent consumption, solution chemistry, and overall economics to identify the preferred commercial operating parameters for the Wudinna project.

By demonstrating that high recoveries are possible with reduced lixiviant levels, Cobra Resources aims to mitigate exposure to ammonium sulphate pricing and supply disruptions. The flexibility shown in the ANSTO tests supports the project's viability by offering multiple pathways for processing that can be tailored to market conditions and regulatory requirements. The next steps involve detailed engineering assessments to finalize the plant design.