Red Metal Limited has just dropped some impressive numbers from its Sybella rare earths project in Queensland, and they could change the game for how these critical minerals are processed.
The company ran large column leach tests on representative samples from the Kary Zone, and the results are deadset encouraging. Using weak sulphuric acid at ambient temperature on coarse-crushed ore — minus 10mm and minus 20mm fractions — they got standout recoveries. Neodymium hit 71% from minus 10mm saprock and 70% from minus 20mm, while transitional ore returned 76% and 75%, respectively. Praseodymium was even better, ranging from 71% to 78% across the same ore types and crush sizes.
The heavy rare earths also performed solidly, with dysprosium extractions between 39% and 41% and terbium between 43% and 44%. And here's the kicker: between 35% and 55% of total rare earth extraction happened in the first 30 days. That suggests the company could start pulling metal out early once each new heap is commissioned — a big plus for cash flow.
Managing director Rob Rutherford didn't hold back. "Our column leach tests on the Kary Zone ores have conclusively shown that we can efficiently extract light and heavy rare earths from the mineralised granite by coarsely crushing it, stacking it and then leaching it with weak sulphuric acid at ambient temperature," he said.
The tests were run on composite diamond core samples from several holes across the northern part of the Kary Zone, giving a more representative picture of how the mineralisation would behave in a bulk mining setup. The fact that saprock, transitional, and blended ore types all responded similarly is another big tick — it means the zones could be co-processed without complicated grade control between weathering domains.
Why does this matter? Because Sybella is a monster deposit. At a 300 parts per million neodymium-praseodymium cut-off, the Kary Zone hosts 936 million tonnes at 334ppm combined neodymium-praseodymium and 31.7ppm combined dysprosium-terbium to 100 metres depth. That resource includes 182Mt of saprock from surface, 157Mt of transitional ore, and 598Mt of fresh granite (which was still leaching at the time of reporting).
The project sits 20 kilometres south-west of Mount Isa and is built around a granite-hosted rare earth system that starts at surface. That means a zero strip ratio in the early weathered material — you don't have to dig through waste rock to get to the good stuff. The company is assessing it as a potential simple heap leach development, similar to large soluble copper heap leach operations.
Red Metal will now push ahead with prefeasibility work, including further column tests on a minus 30mm fraction, taller 6-metre columns, ion-exchange purification studies using the leach liquors, and geotechnical work to determine heap stack heights. The coarser minus 20mm results are particularly useful because they point to possible savings in crushing, pad size, and overall operating costs.
The company's broader exploration book gives it other levers too — gold work at Pardoo in WA, copper-gold targets at Pulkarrimarra in WA and Pernatty Lagoon and Callabonna in SA, plus government co-funded drilling across priority targets in Queensland and WA. But for now, Sybella is the headline act.
If Red Metal can keep converting its lab work into practical engineering numbers, its Mount Isa rare earths push may have just taken a meaningful stride from clever concept towards a much stronger development case.