Heavy Rare Earths’ ongoing metallurgical test work at its Cowalinya project in the Norseman-Esperance region of WA is continuing to deliver – with the grade increasing twofold and magnet rare earth extraction at 91.3%.

Initial sizing test work showed an average of 78.5% of the rare earths are hosted in the fines (-25μm) fraction which comprises 37.2% of the bulk saprolite feed mass, and simple recovery of the fines fraction has been shown to deliver more than a twofold increase in rare earth grade.

These results enable the design of an upstream process flowsheet for the project that removes gangue from saprolite via simple screening and desliming cyclones.

In addition, diagnostic leaching test work has produced very high extractions of magnet rare earths – as high as 91.3% in fact – achieved with acid consumption as low as 3.8kg/t.

Heavy Rare Earths (ASX:HRE) says this points to the potential for a technically and commercially viable processing route for magnet rare earths produced by the project.

A program is now underway to develop a downstream flowsheet to a Mixed Rare Earth Carbonate (MREC) product and generate samples for customer assessment.


Accelerating test work in the coming months

HRE says the diagnostic leaching results justify the company accelerating its metallurgical test program over the coming months.

Work will include optimising the leach conditions focusing on maximising magnet rare earth extractions whilst minimising acid consumption.

The company will also extend the program by treating an additional 50 (6-metre) composites from across the 35km2 area earmarked for resource expansion under optimised leach conditions.

This builds on the excellent results from treating 13 (4- and 5-metre) composites from the current resource of 28 Mt @ 625 ppm TREO.

“We are making excellent progress on our metallurgical program to establish an optimal process route for the rare earth resources at Cowalinya,” HRE executive director Richard Brescianini said.

“Our earlier reported sizing work gave us confidence that simple, low-cost screening is capable of delivering a twofold increase in rare earth concentration for leaching.

“More recent diagnostic leaching of this upgraded material has yielded a number of highly promising magnet rare earth extractions with low acid consumption, both of which are central to technical and commercial viability.”


MREC expected by the end of the year

“Whilst we acknowledge some variability in these results and the need to further optimise leach performance, our forward program now has its sights firmly set on producing samples of a mixed rare earth carbonate, the first possible entry point by HRE into the rare earth supply chain,” Brescianini said.

Subject to the success of the downstream program, the company plans on making MREC samples available to refiners in Europe, Asia, the United States and Australia to determine marketability.

These metallurgical programs are expected to be completed in Q4, shortly after HRE anticipates reporting a new mineral resource estimate and a maiden exploration target for the Cowalinya project.




This article was developed in collaboration with Heavy Rare Earths, a Stockhead advertiser at the time of publishing.


This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.