OD6 achieves high metallurgical recovery rates of up to 90% at Splinter Rock for all magnet rare earth oxides (MagREO)
Data is being considered as part of the future resource upgrade expected to be available this quarter
Phase 4 metallurgical leaching and processing optimisation work is underway at ANSTO
Special report: OD6 continues to firm up project economics at Splinter Rock with latest metallurgical test work achieving up to 90% recovery across 71 new samples and multiple prospects.
OD6 Metals’ (ASX:OD6) Splinter Rock project near Esperance, WA covers some 4,828km2 of ground and holds one of the largest and highest-grade resources in Australia: 344Mt at 1,308 TREO with substantial further upside.
The project is in a prime location for future development with existing infrastructure such as sealed roads, local renewable power connection, and the Esperance port a mere 50km away.
OD6 is targeting a resource expansion at Splinter Rock based on Phase 3 drilling results which returned 58m at 2,060ppm TREO from 21m, 77m at 1,429ppm TREO from 18m and 69m at 1,457ppm TREO from 15m at Inside Centre prospect.
The Inside Centre is a new 2km x 1km discovery up to 69m thick and boasts the potential to be a standout, first stage project.
Metallurgical test work to date
Lately, the company has been focused on identifying the best metallurgical areas to refine the processing route at Splinter Rock.
OD6 has partnered with two research organisations – the Australian Nuclear Science and Technology Organisation (ANSTO) and CSIRO – to improve the extraction of rare earth deposits at the project.
Funds from a recent $1.5m placement were spent on the ANSTO program, focusing on optimising the leach recovery and impurity removal of coarse material across various regolith types at four large prospects (Prop, Centre, Scrum and Flanker).
OD6’s goal is to produce a mixed rare earth carbonate product that will enable the completion of the scoping study.
Splinter Rock Scrum and Centre metallurgical sample drill hole locations on AEM model clay thickness. Pic via OD6
High recoveries from 71 samples at Splinter Rock
The company continues to achieve high metallurgical recoveries at Splinter Rock with new results averaging 60% magnet rare earth element (MagREE) recovery at 25g/l HCl (excluding basin edges and carbonaceous shales).
A total of 71 samples were selected from a wide variety of clays, locations and depths to develop a geo-metallurgical understanding of recovery across the various regolith types at two large prospects (Centre and Prop).
The centre prospect returned between 42% to 90% recovery of Mag REE, the Inside Centre prospect hit between 44% to 76% and the Prop prospect achieved between 41% to 77%.
Leach process and conditions
These results were achieved using the simple acid leach method, a process which involves a project specific bottle roll test procedure utilising a 25 g/L hydrochloric acid solution.
According to OD6, the solution was maintained at 30°C and ambient pressure, with a 4 wt% solids density over a 24-hour period.
Recoveries are then calculated based on the difference between the assayed solid head and solid residue using a 4-acid digestion method.
The bottle roll method is devised to be an inexpensive and fast technique for determining the leachability of samples.
‘As good or better than Brazilian clay-hosted rare earth plays’
“The results show that the Splinter Rock recoveries are as good as or better than the Brazilian clay hosted rare earth plays that have gained so much attention over the last 12 months,” OD6 managing director Brett Hazelden says.
“They continue to affirm that we are Australia’s premier clay-hosted rare earth deposit.
“The Inside Centre recoveries of ~60% when combined with grades of between 1,400 to 2,200ppm TREO, across an extensive 2km by 1km areas, with substantial thicknesses between 20 to 77m, a low stripping ratio, plus low acid consumptions continue to be a standout for the company,” he says.
“These metrics align closely with the essential value drivers we believe are crucial for the economic viability of clay hosted rare earth projects both in Australia and globally.”
What’s next?
These results will be considered as part of the future resource update expected to be available this quarter.
Meanwhile, Phase 4 metallurgical leaching and processing optimisation work is underway at ANSTO.
This article was developed in collaboration with OD6 Metals, a Stockhead advertiser at the time of publishing.
This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.
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