Ark Mines (ASX:AHK) has announced that IHC Robbins has generated a commercial monazite product sample from a heavy minerals (HM) concentrate sourced from its Sandy Mitchell deposit in Queensland.
Feedstock to produce the HM concentrate was wholly sourced from a bulk retained fraction of Ark Mines’ resource drilling campaign at the Sandy Mitchell deposit.
The monazite product graded 54.8% total rare earth oxide (TREO) and 1.49% yttrium oxide in the highest grade stream.
In TREO, the proportion of neodymium praseodymium oxide was graded at 23.4%. A strong titanium upside was also demonstrated, with a premium production of 73.5% titanium dioxide.
Testwork returned three other product streams including 52.6% TREO in the coarse stream, with the expected blended TREO grade of all four streams combined at approximately 52.2%.
In all four product streams, cerium recovery was marked at 65.43%, which IHC Robbins says could be improved in a commercial plant by recirculating intermediate streams.
Meanwhile, the fine monazite con was achieved using reverse magnetic separation and triboelectrostatic separation.
Studies are ongoing, with a second tranche of work focused on optimising zircon, biotite, muscovite, and garnet product streams.
Findings are expected to inform stage two metallurgical testwork for Ark Mines, which is currently in progress.
Ark Mines Managing Director Ben Emery describes the product results as a “really important step forward” for the Sandy Mitchell Project.
“This study bridges the gap between recognising the commercial potential of the project and demonstrating the potential through the successful production of commercial grade monazite and titanium products,” Emery says.
“The monazite product achieved 54.8% TREO, placing it near the upper end of the normal commercial specification range.
“And this is done by simple gravity processes with no chemicals or crushing. Nature does our work.
“Whilst there is still further metallurgical testwork to be completed, these results provide a level of confidence in the quality of the resource, as we look to define the most efficient processing pathway to commercial production.”
Ark Mines is a critical minerals exploration and development company with assets in North Queensland.
Write to Maddison Elliott at Mining.com.au
Images: Ark Mines
