• New rig to accelerate REE sampling at Sandy Mitchell
  • Sampling quality is also expected to improve
  • Sand-hosted mineralisation is amendable to simple gravity beneficiation


Sampling for rare earths at Ark’s Sandy Mitchell project in north Queensland is set to accelerate after the company acquired a hydraulic driven auger rig.

The auger rig, which is custom mounted on a 4WD Landcruiser for quick movement around the drill site and to minimise its impact, has being modified to drill sands and will be operated by the company’s on-site staff.

Significantly for Ark Mines (ASX:AHK), the rig will reduce availability issues of contractors and significantly lower the cost of drilling whilst improving the quality of sampling.

“In this market, the ability to deploy our own customised augur rig provides so much more operational flexibility for the Ark technical team,” executive director Ben Emery said.

“Along with a much lower cost per meter to drill, the auger rig will provide a better quality sample for future lab analysis.”

Emery added that given the expansive size of the Sandy Mitchell project, having the rig being vehicle-mounted provided the company with more optionality to appraise the scope of the resource in a timely manner.

“With an on-site technical team that resides locally, the rig will be fully-staffed as required and we are confident the results from the auger drill program will quickly offset the acquisition cost over the coming months as the drill program progresses,” Emery explained.


An advanced, unique REE project

The company acquired Sandy Mitchell, which has already been the subject of significant exploration work by previous owners, in March for just $200,000 in cash.

REEs have been at the centre of attention in recent times due to their use in the fabrication of permanent magnets which are used in electric vehicle motors and wind turbines.

However, while most projects are focused on either hard rock or clay-hosted mineralisation, Sandy Mitchell’s unique sand-hosted mineralisation offers several compelling advantages.

Chief of these is the potential for the company to quickly commercialise the project using low-cost gravity separation and processing – potentially lower than both hard rock and ionic clay projects – with a focus on extracting higher value heavy rare earths and NdPr.

Previous exploration returned very high grades up to 18.4% total rare earth oxides (TREO) hosted in sands following pan concentration. Notably, valuable magnet REEs neodymium and praseodymium make up to 25% of the TREO content.

Work has also found that the sand-hosted mineralisation is amenable to straightforward beneficiation by gravity processing.

Ark has also completed a Phase 1 aircore drill program of 144 holes where preliminary assays have returned REE and heavy mineral mineralisation in every hole.

Adding further interest, every hole drilled to date have shown no overburden or clay layers from the surface to the bottom of the sand profile – a finding that is likely to vastly simplify mining and processing.

The company, which sees opportunity for a quick, low capex development, is already applying for a mining licence.

In addition to Sandy Mitchell, Ark holds the Mount Jess copper and iron project and the Gunnawarra nickel and cobalt project – the latter of which received a contained maiden JORC resource estimate of 1.34Mt of nickel, 602,000t of cobalt and 191,500t of copper in December last year.


Drill plans

Ark is currently adding some safety features to its new rig before setting it the task of carrying out a full drilling program for the rest of this year.

This extensive step-out drill program will test priority target areas and expand the known mineralised zone.



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.