ASX announcement — 17 September 2026
Mount Ridley Mines (ASX: MRD) has reported the final leach test in the initial program for its wholly owned, patent-pending Selectro™ process. On an unbeneficiated Grass Patch composite, Test 3 achieved 91.8% scandium recovery, up from 80.0% in Test 2, while using approximately half the reagent dose applied in Tests 1 and 2.
Recovery gains at a lower dose
- Heavy rare earth element recoveries reached up to 86%, averaging approximately 84%, versus a 78.5% average in Test 2.
- Light rare earth recoveries reached up to 81%, averaging approximately 77%, versus 72.5% in Test 2.
- Gallium recovery declined to approximately 41.5% from 55.8% in Test 2, illustrating that different elements respond differently to the leach conditions.
The test used the same eight-sample composite from five historical drill holes as the earlier Selectro tests. Nagrom conducted the laboratory-scale work at atmospheric pressure without prior beneficiation or process optimisation. The company says the lower reagent dose could reduce costs, but detailed reagent chemistry and concentrations have not been disclosed, and commercial operating costs have not yet been established.
What comes next
Mount Ridley plans further reagent optimisation, including work on the balance between scandium, rare earth and gallium recovery. Flotation testwork is underway to inform beneficiation before bulk-sample testing. The company also plans to test the process on third-party feed. These are early laboratory results rather than demonstrated pilot-scale recoveries or a saleable product.
For a separate assessment of the results and risks, read the Cashu Research Selectro Test 3 note.