New leach testwork on samples from North Queensland’s Kennedy project points to extremely encouraging recoveries of rare earth elements (REE), especially magnet rare earths, according to DevEx Resources.

The metallurgical tests carried out by the Australian Nuclear Science and Technology Organisation (ANSTO) have enhanced the previously reported recoveries from the ionic adsorption clay-hosted REE project.

DevEx said they demonstrated rapid recoveries by desorption of the rare earth elements in the first 30 minutes using an ammonium sulfate (AMSUL) solution in weak acidic conditions.

‘Pleasingly, the results show that rapid dissolution of (magnet rare earth elements) in weak acid conditions is occurring throughout the 53 samples collected, with many samples achieving recoveries of more than 50 per cent and up to 73 per cent,’ the company stated in an update to the ASX.

‘Importantly, there is low dissolution of gangue element cerium reported across all four progressive test conditions … a key characteristic of favourable ionic clay mineral systems.

‘One of the key drivers of the testwork was to identify how MREE recoveries and acid consumption performed from within the inferred mineral resource estimate.

‘Pleasingly, the results received have indicated good consistency over the majority of the deposit.’

The Kennedy inferred mineral resource lies within unconsolidated gravel clays with no overburden, making priority areas easily accessible.

DevEx said the new leach testwork results provided the opportunity to progress to more definitive bulk sampling, with the focus being on areas that coincided with high MREE (magnet rare earth elements) recoveries and high MREE grades.

The testwork was undertaken with a grant from the Queensland Government’s Collaborative Exploration Initiative.