Kairos Minerals (ASX:KAI) says metallurgical testwork has shown it can achieve high recoveries of rare earths from the Black Cat prospect, part of the Roe Hills Project in Western Australia.
Tests undertaken on drill samples of rare earths-mineralised clay demonstrated recoveries of between 89.9 and 97.4% using hydrochloric acid.
The four samples ranged between 2,072 and 5,686 parts per million total rare earth oxides.
The company’s goal was to prove up the economic potential of the prospect before drilling out a large resource.
Managing Director Peter Turner says Kairos needs to make sure it can beneficiate or upgrade the mineralisation to a saleable product for the market.
“These early tests demonstrate that there are no refractory components to the mineralisation that are often seen with clay-hosted REE projects,” he says.
“We now have good reason to be very confident with our Roe Hills REE project, with high in-situ grades of the clay-hosted mineralisation and large areas interpreted from the gravity results to be underlain by enriched syenites that will be tested in the next round of cost-effective aircore drilling.”
Simple screen beneficiation results demonstrate that the fine fraction contains over 70% of the total rare earths, with recoveries averaging 68.2 to 74.8% total rare earth elements.
A 500g sub split was prepared from each of the four samples and screened at 106, 75, 53 and 20 microns.
Kairos says the high-value magnet REEs neodymium (Nd) and praseodymium (Pr), as well as the lesser known but valuable samarium (Sm), were upgraded in the finer fraction (20 microns) in two of the four samples.
Samarium is used in partnership with cobalt to create strong magnets, though not quite as strong as neodymium magnets.
“Several samples also show the REEs reporting to the finer fraction of the clays, especially in the valuable rare earths Sm, Nd & Pr,” Turner says.
“This gives us encouragement to review a second stage of test work.”
The individual sizing analysis tests allow $31.5 million market capitalised Kairos to identify potential beneficiation routes to upgrade the mineralisation prior to leaching by simple sizing/sieving.
Kairos is planning to undertake further hydrochloric acid leach testing at reduced concentrations to determine if the rare earths can be more economically recovered.
The company will also organise heritage surveys ahead of a potential 8,000m aircore drilling program over Black Cat and surrounding targets.
The Black Cat prospect sits 120km east of Lynas Rare Earths’ (ASX:LYC) rare earth processing facility in Kalgoorlie, Western Australia.
Write to Angela East at Mining.com.au
Images: Kairos Minerals
