Red Metal Limited has put another piece of the metallurgical puzzle in place at its Sybella rare earths project near Mount Isa, with two-metre column leach tests confirming the processing potential of the Kary Zone's dominant fresh granite ore.
The tests on granite crushed to 10 millimetres achieved neodymium recoveries of 65 per cent and praseodymium recoveries of 68 per cent at ambient temperature, using 19 kilograms per tonne of sulphuric acid. That is materially lower than the 23 to 27 kilograms used in tests on the two weathered ore types that sit above the granite. Acid is one of the biggest costs in heap leaching, the process in which a chemical solution is trickled through crushed ore to dissolve the valuable metals.
Fresh granite makes up 598 million tonnes of the Kary Zone's 936-million-tonne inferred mineral resource, with saprock and transitional ores contributing 182 million and 157 million tonnes respectively. The resource grades 334 parts per million neodymium-praseodymium and 31.7 parts per million dysprosium-terbium, and remains open at depth, with drilling encountering rare earths down to 240 metres.
Managing director Rob Rutherford said: "The positive column leach test on the fresh granite mineralisation from the Kary Zone has demonstrated the heap leach potential of the very large fresh granite resource located immediately below the near-surface, saprock and transitional ores which remains open at depth."
The new data will feed into the Sybella prefeasibility study, which is slated for completion in the first quarter of 2027. In parallel, the company is running a six-metre column test using 20-millimetre crushed ore to replicate commercial heap leach conditions, and has drill rods turning on a 5000-metre campaign to upgrade and extend the deposit. Earlier two-metre tests on the overlying ores returned neodymium recoveries of 76 per cent from transitional ore and 71 per cent from saprock.
The results land as Australia and its allies ramp up efforts to loosen China's grip on global rare earths supply chains. Neodymium and praseodymium are used to manufacture permanent magnets for electric vehicles, wind turbines and industrial equipment.
Red Metal is also pursuing a "Big Copper" strategy in the Mount Isa province, and recently lodged 17 new tenement applications to take its regional landholding to 5800 square kilometres.