American Rare Earths Ltd (ASX:ARR, OTCQB:ARRNF) has reported the first production of high-purity light and heavy rare earth oxide (LREO and HREO) concentrates from its Halleck Creek project in Wyoming, with purities of 96.4% and 97.1%, respectively. Both are critical feedstocks for permanent magnets, widely used in defence, clean energy and advanced technology applications.
LREO and HREO Products from UK Test Work.
The concentrates were produced from the project’s allanite-based ore by the University of Kentucky, in collaboration with Lawrence Livermore National Laboratory and Penn State University under the SynBREE consortium, as part of the US Department of Defense’s DARPA EMBER program, which is trialling biotechnology-based methods to separate and purify rare earth elements for critical applications including permanent magnets.
First-time production using Halleck Creek ore
This marks the first time that rare earth oxide concentrates have been produced from Halleck Creek ore. Since 2023, ARR has supplied around 840 kilograms of material from 36 drill holes for the EMBER project, testing biotechnology-based separation and purification methods.
Locations of Holes used for UK Testing.
The SynBREE consortium’s laboratory-scale flowsheet uses the Lanmodulin protein to recover rare earths from leachates, offering a potential alternative to conventional separation processes. While still in the research phase and yet to be commercially proven, the method successfully extracted rare earth element (REE) oxides from allanite minerals and could be considered alongside future processing options.
Interim CEO Joe Evers said the results were another significant milestone for the SynBREE consortium.
“These results provide a very meaningful third-party validation that light and heavy rare earths oxides can be produced from the Halleck Creek allanite-hosted ore body,” he said.
Outside current PFS scope
ARR stressed that the SynBREE work is independent of its ongoing pre-feasibility study (PFS) at Halleck Creek. The company’s wholly owned US subsidiary, Wyoming Rare (USA) Inc, is focused on developing a flowsheet using conventional mineral processing techniques, with optimisation work already under way.
While the EMBER project explores emerging bio-recovery pathways, the PFS aims to define a commercially viable process for mining and refining rare earths onsite in Wyoming, positioning Halleck Creek as a potential cornerstone of US supply chain security.
Technical process
The University of Kentucky’s process involved:
- Concentrating allanite using heavy liquid separation.
- Leaching with hydrochloric acid.
- Removing about 98% of iron, aluminium and silica using sodium hydroxide (with about 15% REE loss in impurity removal).
- Solvent extraction to separate light and heavy rare earth-rich solutions.
- Precipitating oxalates and calcining to produce the oxide powders.
- The team recovered about 82% of total rare earths from the leachate solution.
ARR’s Halleck Creek project is considered one of the largest known rare earth deposits in the US, strategically located in a mining-friendly jurisdiction with potential for cost-efficient open-pit mining and streamlined permitting. The company continues to advance both conventional and innovative processing pathways to meet growing domestic demand for critical minerals.