• AHK reports rare earths in every hole assayed to date at Sandy Mitchell rare earths project in QLD
  • The project is hosted in sands which could enable simple and low-cost processing
  • Stage 2 drilling is under way with a maiden resource in the works


Ark Mines is off to a flying start at its Sandy Mitchell project in North Queensland, confirming rare earths mineralisation in every interval of every hole assayed to date. 

Sandy Mitchell is unique compared to other rare earths (REE) deposits, as the materials are hosted in fine sands known as terrestrial placer deposits, which are amenable to simple panning into a concentrate.

Ark Mines (ASX:AHK) says this could result in a potentially fast-start up beneficiation gravity processing model that will have lower processing costs than both hard rock and ionic clay-hosted REE deposits.

The first batch of assays from the company’s 144 hole stage 1 drill program comprised all critical light rare earths as well as heavy rare earths including dysprosium (Dy), terbium (Tb), holmium (Ho), erbium (Er), thulium (Tm) ytterbium (Yb), yttrium (Y) and excluding only lutetium.

Ark says niobium (Nb205) grades are also consistent is assays with magnet metals accounting for 23% of the Total Rare Earth Oxides (TREO).


Commercial grades and straightforward processing

Assay results included:

  • TREO plus yttrium and scandium average grades for every metre assayed 503.5ppm with highest grades of 1,175.4ppm;
  • Light rare earth average grade for every metre assayed 454.3ppm with the highest grade of 1,048ppm;
  • Heavy rare earths plus yitrium average grade for every meter assayed 49.2ppm with the highest grade of 129.3ppm; and
  • Magnetic rare earth oxides average grade for every metre assayed 109.4ppm with the highest grade of 269.7ppm.

The company says the assay grades are considered commercial and highly encouraging given Sandy Mitchell is a very large 147km2 placer (sand) deposit.

“These first assays are particularly pleasing and highlight the potential scale of rare earths mineralisation at Sandy Mitchell,” AHK executive director Ben Emery said.

“We are very confident that Sandy Mitchell has the potential to develop into a large-scale Australian rare earths project that also benefits from minimal environmental impact due to its unique geological profile, where rare earths are hosted in sand and can be extracted by straightforward beneficiation by gravity processing which removes the need for pollutive extraction processes.

“Also, given the rare earths are hosted in sands, the grades we are reporting today are regarded as commercial as processing to deliver a saleable concentrate is much more straight forward given Mother Nature has done our crushing.”


Ark Mines ASX AHK
Sandy Mitchell rare Earth and Heavy Mineral project location. Pic via Ark Mines


Stage 2 drilling already under way

Notably, the drilling only covered an area of 1.3 km2 which is 1.2% of the peak radiometric reading on the lease. Stages 2 to 4 will ultimately cover the full anomaly with Stage 2 drilling underway.


Ark Mines ASX AHK
Drill holes locations at the Sandy Mitchell Rare Earth and Heavy Mineral project. Pic via Ark Mines


“Stage 2 extension drilling has now commenced, and our on-site team is hard at work on the detailed extension drill program which will ultimately provide us with REE assays across the full rare earths anomaly – an exciting prospect given the highly promising results from the Phase 1 program which covered just 1.2% of the site area where peak radiometric reading was recorded in preliminary testing,” Emery said.

This work will form the basis of a maiden resource estimate for the project, with metallurgical test work also under way – including ore characterisation and HMC production evaluation, including the suitability of beneficiation by gravity.

Ark has also commenced studies to evaluate REE mineral beneficiation processes, including floatation and conventional techniques.



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.