Defense Metals said 14 pilot plant processing runs have been completed at the SGS Canada metallurgical test facility in Lakefield, Ontario since initiation of pilot plant testwork in June.

The process run concentrate grades ranged from 45.4-56.7% Light Rare Earth Oxides (LREO). Process recovery ranged from 53.8-79.1% LREO, or an average of 70.2% LREO.

The tests processed 16 tonnes of bulk sample feed over 118 hours of operation, with approximately 750 kilogrammes of flotation concentrate produced.

The scaled-up flotation pilot plant results to date compare "very favourably, and with respect to concentrated grade exceed", benchmark locked-cycle flotation tests, noted the company. 

Successive tests have been conducted under varying process conditions designed to improve the circuit stability and metallurgical performance, said Defense.

"We are exceedingly pleased with these initial flotation pilot plant test results. The Wicheeda REE Deposit mineralisation continues to deliver exceptional metallurgical performance," said Craig Taylor, chief executive of Defense Metals. "We have shown that in a pilot plant setting we are able to exceed concentrate grades achieved during bench-scale flowsheet development."

The Wicheeda flotation test charges were prepared by SGS from the 30t Wicheeda sample which was crushed to nominal 12.7 mm (1/2") using a combination of jaw and cone crushers.