In this latest testwork, ANSTO conducted two impurity removal (IR) trials on rare earth-enriched leach solutions produced from a 1.2 kg sub-sample of the 100 kg bulk sample, taken from trial pit DLP002 within the Deep Leads resource area. At near-optimum conditions (pH 5.9 and 6.2) the key impurity, aluminium, was almost completely removed, while more than 98% of rare earth elements remained in solution.

A critical metric for MREC product quality is the ratio of aluminium to total rare earths (Al:TREE ratio) in the solution following impurity removal. In these two tests, the Al:TREE ratio was less than 0.005, which is likely to be maintained in the final MREC product. This is a very low level of aluminium and is likely to be appealing to customers.

This result provides further evidence that the Deep Leads resource represents the prized combination of high Dy and Tb grade, high rare earth recovery using low-cost conditions and low impurities that is conducive to producing a high value MREC product at low cost.