Ark Mines plans additional metallurgical voyage 

Ark Mines (ASX:AHK) is lining up additional metallurgical testwork after producing a ‘high-grade’ rare earth concentrate at its Sandy Mitchell Rare Earth and Heavy Mineral Project in North Queensland.

The $10.47 million market capitalisation company says the results, generated from first-pass water-based beneficiation testwork undertaken by Mineral Technologies, demonstrate ‘excellent’ recoveries and will be incorporated into a Scoping Study ahead of a planned Prefeasibility Study (PFS). 

Results also confirm the material is amenable to straightforward beneficiation by water-only, low-cost gravity processing. 

Ark confirms it will now evaluate the final mineral product for multiple potential commercial markets and build an initial business case, though further assays are pending. 

The company reports final concentrate assays returned 51.9% total rare earth oxide (TREO) (519,000 parts per million) and contained mostly lanthanum, cerium, praseodymium, and neodymium plus heavy rare earths dysprosium and terbium. 

These commodities collectively represent a ‘very high-value’ saleable product. 

Meanwhile, direct cerium oxide recovery from gravity feed to REM concentrate is estimated to be 71.7%, although testwork calculated that in a normal recirculating gravity plant, an overall recovery of 83.8% may be achieved. 

Further, content in this process is used as a tracer for the rare earth-bearing mineral monazite, which was subsequently upgraded from 0.04% in the as-received feed to 23.6% in the cleanest product. Similar upgrade trends are observed for zirconium dioxide. 

As of 11:45am AEDT on 24 November, Ark Mines’ share price had increased by 19.047% to $0.25. 

The company says its ‘extensive’ drilling program is ongoing, with 2 rigs operating to extend drilling depths to 24m beyond the average current hole depth of 10m. Drilling has also been designed to confirm further rare earths mineralisation in new areas across the 145km-square permit area. 

Ark Mines Executive Director Ben Emery says these results, in conjunction with the 2-rig drilling program, are helping the company to define Sandy Mitchell as a project of ‘significant’ scale. 

“Importantly, the first-pass beneficiation testwork showed that the highest REE extraction grades were achieved by simple gravity separation — thus confirming a key value-add of this project.

Concurrently, our 2-rig drill program continues to advance very well. This program is helping us to rapidly define Sandy Mitchell as a rare earths project of considerable scale, and with the combination of more assays from step-out drilling and additional metallurgical test work results, we expect to soon be able to further communicate the project’s commercial benefits — not just for rare earths but also for heavy minerals that also have considerable value.”

“the first-pass beneficiation testwork showed that the highest REE extraction grades were achieved by simple gravity separation — thus confirming a key value-add of this project”

Ark Mines is focused on moving from explorer to developer at its Sandy Mitchell Project, which sits 300km west of the city of Cairns in North Queensland.  

As of 30 September 2023, Ark Mines had $3.18 million cash and cash equivalents at hand, according to its latest quarterly report.

Write to Adam Drought at

Images: Ark Mines
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Written By Adam Drought
Born and raised in the UK, Adam is a sports fanatic with an interest in Rugby League and UFC/MMA. When not training in Muay Thai and Brazilian Jiu Jitsu, Adam attends Griffith University where he is completing his final year of a Communication & Journalism degree.