Meeka Metals Ltd (ASX:MEK) welcomes results from its upstream beneficiation tests, part of the ongoing metallurgical test program to develop a pathway to commercial production from the Circle Valley Rare Earth Project in WA.
Test-work advances
The beneficiation process improves the grade of the samples, removing non-target elements.
Meeka managing director Tim Davidson said: “This positive test-work shows most of the rare earth elements are hosted in the fine fraction of the clays.
“This presents an opportunity to remove waste and significantly upgrade the rare earth grades using simple, cheap and well-understood upstream mineral processing techniques.”
Key findings from the test work include:
- Between 90.4% and 62.5% of the rare earth elements were contained in the fine fraction (-20µm size fraction).
- The fine fraction (-20µm) only contained between 34.5% and 60.4% of the total sample mass.
- By rejecting the coarse fraction (+20µm), between 65.5% and 39.6% of the sample mass can be removed while between 90.4% and 62.5% of the rare earth elements can be retained.
- Rejecting the coarse fraction (+20µm) delivered 1.81 times, 1.15 times and 1.91 times the total rare earth oxide (TREO) grade uplift of the raw sample grade for each of the three test samples respectively.
Simple mineral processing techniques
The process can be applied to discard the coarse fraction (+20µm) and remove up to 65.5% of the mass, removing waste material and deleterious elements, while retaining up to 90.4% of the rare earth elements.
On a commercial scale, this would involve particle size separation through scrubbing to produce a slurry prior to screening and hydro-cyclone classification to discard the non-target elements in the coarse fraction, while retaining the valuable -20µm size fraction, which hosts most of the rare earth elements.
This increases the rare earth grade by up to 91%, rejecting the coarse fraction (+20µm) with the grade increase evenly distributed between light, heavy and magnet rare earth elements.
Next up
The next phase of metallurgical testing is underway with recovery optimisation test-work.
This includes leach tests on -20µm clay fraction to develop a recovery curve for both ammonium sulphate (ionic portion of the rare earth elements) and acid (non-ionic portion of the rare earth elements).
“Our metallurgical team is now focused on the next phase of test-work, which will optimise the leach conditions for extraction of the rare earth elements from the fine fraction of the clays,” said Davidson.
“In addition to the ongoing metallurgical test-work, drilling continues to show a shallowing cover profile to the northwest at Circle Valley, corresponding with a +1,000ppm high-grade component of the rare earth mineralisation, rich in NdPr magnet rare earth elements.
“This shallow high-grade northwest trending mineralisation at Circle Valley will be a focus for mineral resource infill drilling commencing in early 2023.
“Delivery of an initial mineral resource remains on track for the June 2023 quarter.”