• Ark Mines has defined a 1.3-1.5 billion tonne exploration target at its Sandy Mitchell project
  • Sandy Mitchell could be one of the largest surface-expressed rare earth projects globally
  • Prefeasibility study underway and further exploration is planned


Special Report: Ark Mines has defined an exploration target for its Sandy Mitchell rare earths project in Queensland of between 1.3-1.5 billion tonnes at 1,250 to 1,490 ppm monazite equivalent, potentially placing it as one of the largest surface-expressed rare earth projects globally.

Just like the recently announced maiden indicated mineral resource of 21.7Mt at 1,419ppm monazite equivalent, the exploration target is based on mineralisation from surface down to an average depth of ~11 metres.

This means there is no overburden removal, with simple mining and low environmental impact smoothing the likely development pathway for the company.

Ark Mines (ASX:AHK) notes that the potential quantity and grade of the exploration target remains conceptual in nature as further exploration may or may not result in estimation of a mineral resource.


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The Sandy Mitchell project with the JORC exploration target highlighted in yellow. Pic via AHK


Large and simple to mine

The exploration target includes a basket of high value Heavy Minerals totalling 15.6 to 22.3 million tonnes of contained HM, comprised of:

  • Monazite from 781,000 tonnes to 1,119,000 tonnes, grading from 590ppm to 710ppm
  • Xenotime from 103,000 tonnes to 148,000 tonnes, grading from 80ppm to 90ppm
  • Zircon from 810,000 tonnes to 1,160,000 tonnes, grading from 620ppm to 730ppm
  • Rutile from 721,000 tonnes to 1,032,000 tonnes, grading from 550ppm to 650ppm; and,
  • Ilmenite from 13,169,000 tonnes to 18,855,000 tonnes, grading from 10,000ppm to 11,930 ppm.

24% of the TREO basket consists of magnet rare earths neodymium, praseodymium, dysprosium and terbium, positioning Sandy Mitchell as one of Australia’s most enriched MREO deposits.

“The sheer scale of the Sandy Mitchell exploration target, up to 1.5 billion tonnes, delivers a clear statement that this is one of the world’s largest surface-expressed, sand-based placer rare earth deposits,” Ark executive director Ben Emery said.

“With the consistent grades of rare earths and heavy minerals from surface to only ~11 metres deep, we are working with an exceptionally large and very simple deposit with an extremely low environmental impact.”


Pre-feasibility study underway

The pre-feasibility study for the project is now underway, along with an expanded phase 2 mineral resource adding to the maiden resource – which was developed from only 1.2% of the available anomaly area at Sandy Mitchell.

The PFS is expected to be reported in Q4 CY2024, with Ark targeting the development of a straightforward, low capex gravity separation plant that produces a monazite concentrate with heavy mineral sands credits.

“Sandy Mitchell has considerable advantages over projects where rare earths are housed in ionic clays or hard rock material,” Emery said.

“Most of the processing has already been done by mother nature, so to produce a monazite concentrate, simple low-cost gravity separation is all that is required.

“Our pre-feasibility study, which has commenced, will illustrate this.

“While pre-feasibility work continues, we are also busy incorporating the second phase of drilling into an updated MRE and we are now advancing on mining and other relevant project development permits.”

In addition, further exploration is planned for 2024 to test the exploration target across its entire area with a grid of 189 auger holes.

Drilling is planned to commence in July and run until the wet season.



This article was developed in collaboration with Ark Mines, 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.