Red Metal (ASX:RDM) said large column leach tests using weak sulfuric acid at ambient temperatures achieved strong rare earth extractions on representative, coarsely crushed ore samples from the Kary zone at the Sybella rare earth elements project in Queensland, according to a Thursday Australian bourse filing.
Tests on two crush sizes of the saprock and transitional mineralization types achieved high rare earth extractions with low impurities in the pregnant leach solutions and low total-acid consumptions.
Neodymium and praseodymium extraction results came in at 71% and 72%, respectively, at the 10 millimeters crush size for saprock mineralization, and at 70% and 71% at the 20 millimeters crush size. Neodymium and praseodymium extraction results came in at 76% and 78%, respectively, at the 10 millimeters crush size for transitional mineralization, and at 75% and 76% at the 20 millimeters crush size.
Between 35% to 55% rare earth extraction occurred within the first 30 days, highlighting the scope for early cash flow once each new heap or heap lift is commissioned.
Its shares rose over 11% in recent trading on Thursday, reaching the highest point in over 13 years.