American Rare Earths (ASX:ARR) said the SynBREE consortium produced a heavy rare earths oxide concentrate and light rare earths oxide concentrate from ore from the Halleck Creek project in Wyoming, according to a Friday Australian bourse filing.

The light rare earth oxide is around 96.4% pure, and the heavy rare earth oxide is around 97.1% pure.

This was part of the US Department of Defense's ongoing Defense Advanced Research Projects Agency Environmental Microbes as a BioEngineering Resource project, seeking to develop a biotechnology-based separation and purification strategy for rare earth elements.

The firm provided around 840 kilograms of Halleck Creek ore to the project from around 36 drill holes.