WATCH: MD Mike Schwarz explains the significance of the new metallurgical results. (4min)
HIGHLIGHTS
- Recoveries of up to 86% TREO achieved in leaching trials undertaken by METS Engineering.
- Recoveries of up to 88% were achieved for the MREOs (Nd, Pr, Dy, Tb).
- Test work indicates a high chloride environment is required to liberate REEs from the clay host material.
- These results suggest that the bulk of the REEs should be extractable and not bound within the lattice structure of the clay particles or in resistive minerals such as zircon or monazite.
- Hydrochloric acid was used to create a high chloride environment. Further test work will involve the substitution of common table salt, or NaCl, to reduce acid costs.
- Additional test work will also include the viability of ion exchange desorption using various ion exchange salts.
- Focus on the existing graphite exploration program at the Lacroma Graphite Prospect continues.
"The successful drilling program in 2022 proved up a large Exploration Target of 110 â 220 Mt @ 635 â 832 ppm TREO and 19-22% Al2O3 at Caralue Bluff. However, our challenge was to improve the recovery process. Over the past few months, through our partnership with METS Engineering we have systematically explored all the processing options and uncovered the right conditions for exceptional Rare Earth Element recoveries. This has opened the path to creating a low cost and effective leaching process. While it is still early days, this has the potential to be an important breakthrough for the economics of the Caralue Bluff Prospect."
DETAILS
Caralue Bluff Clay Hosted REE Prospect
The Caralue Prospect was initially established as a high purity kaolin prospect with the identification of thick intervals of bright white kaolin, close to surface, in several historical drill holes. A 2022 drilling program undertaken by iTech identified significant REEs, in the kaolin rich intervals, over a large area. The Caralue Bluff Prospect contains an Exploration Target of 110-220 Mt @ 635-832 ppm TREO and 19-22% Al2O3. The Exploration target (reported on 18 August 2022 as âExploration Target Defined at Caralue Bluffâ) is based on 80 drill holes, from a total program of 260 holes, across an area of approximately 12km x 12km. Importantly it remains open in multiple directions allowing for possible expansion. REE mineralisation is rich in key magnet REEâs (Nd-Pr-Dy-Tb) averaging 25% of the REE basket.
Aircore Drilling on the Eyre Peninsula (2022)
Metallurgy Results
A single composite sample from the 28 samples of ionic clay intervals was prepared from drill hole CBAC22-162 (10m @ 1157 ppm TREO reported on 22 August 2022 as âFinal Drill Results from Caralue Bluff Prospectâ). Three HCl leaching tests were performed under comparable conditions (80°C for 4 hours, 20% pulp density) with different HCl concentrations used, namely 10%, 20% and 32%. Sub-samples of the leaching solution were taken at pre-determined intervals: 15, 30, 60, and 120 mins and these solutions were assayed. At the end of the 4-hour leaching test, the slurry was filtered, washed and dried. Both the filtrate and residue were also assayed.
