American Rare Earths Ltd (ASX:ARR, OTCQB:ARRNF) has received further evidence of the critical minerals potential of its US projects with a 64% increase in the rare earth elements resource at Halleck Creek in Wyoming.
An updated JORC 2012-compliant resource estimate completed as part of a ‘Technical Report of Exploration and Updated Resource Estimates of the Halleck Creek Rare Earths Project’ has provided strong encouragement.
In-situ resources increased by 64% on the September/October 2023 maiden resource estimate to 2.34 billion tonnes at 3,196 ppm total rare earth oxides (TREO) using a 1,000 ppm TREO cut-off.
Of this, 27% or 1.81 million tonnes, are the valuable and in-demand magnetic rare earth oxides (MREO) with an average grade of 774ppm MREO.
Importantly for future Halleck Creek development potential, there has been a 128% increase, or 795 million tonnes, in measured and indicated resources to 1.42 billion tonnes at a grade of 3,295 ppm TREO using a 1,000ppm TREO cut-off.
Inferred resource estimates also increased by 15% or 117 million tonnes.
Estimated rare earth resources at Halleck Creek (1,000ppm TREO cut off).
With the updated resource estimated from drilling carried out over just 25% of the project area, there is strong potential for further resource growth. The existing resource is also open at depth and along strike.
American Rare Earths CEO Donald Swartz said: “These results are illustrative of the enormous potential of the project when the resource increases 64% during a developmental drilling campaign, which increased measured/indicated resources by 128%.
“Typically, you’ll see the resource decrease as infill drilling takes place – instead we’re seeing the opposite, with only 25% of the project being drilled to this point.”
Grade tonnage curve for TREO 2023 v 2024 update.
Strong recent drill results
From April 2022 through October 2023 ARR drilled 53 reverse circulation (RC) and 17 core holes for a total of 70 holes and 9,031 metres.
Adding ARR’s strong drilling results from September/October 2023 to the geological model for Halleck Creek expanded the resource laterally and vertically.
This drilling also provided data to geostatistically define measured resource extents at Overton Mountain and redefine indicated resource extents at Red Mountain with high degrees of geological confidence.
Odessa Resources Ltd, from Perth, Australia, updated the Halleck Creek resource model using Leapfrog Edge, with all drill hole data variograms and block model parameters updated. Grade estimation was carried out using an ordinary kriged (OK) interpolant.
ARR is working with Stantec (TSX:STN), an international engineering consulting provider, to develop a JORC scoping study at Halleck Creek with technical, mining and economic designs being evaluated as part of this work.
Stantec has determined that an economic cut-off grade of 1,000 ppm TREO defines in-situ resource estimates within proposed mining and economic limits.
In the opinion of the Competent Person, the 1,000 ppm TREO cut-off grade meets the conditions for reporting of a mineral resource with reasonable prospects of eventual economic extraction.
A 1,500 ppm cut-off grade was used in the 2023 resource determination, prior to advancing metallurgy.
“The low-cost mine plan when combined with the breakthroughs around metallurgy have increased our confidence and excitement about this world-class deposit,” said Swartz.
“At 27% MREO, we look forward to releasing the results of the scoping study that is nearing completion.”
MREO distribution in drilling data.
ARR intends to use traditional open pit surface mining at Halleck Creek. The mineralised rock material occurs at surface and continues at depth as shown in block models.
Previous preliminary metallurgical test-work demonstrated that up to 93% of gangue material can be separated from mineralised rare earth minerals using dense media separation (DMS) and wet high-intensity magnetic separation (WHIMS).
ARR is undertaking preliminary work on leaching and refining of REE from WHIMS feed concentrate.
Initial testing indicates that recoveries between 80% and 100% of light REE can be achieved through direct acid leaching at lower temperatures. The results from this testing will be announced as soon as completed.
ARR is developing needs assessments for the potential development of mines at Halleck Creek. in phases.
The first phase consists of acquiring a licence to explore on state mineral leases from WDEQ to collect rocks for bulk material testing and pilot-scale metallurgical test-work. The second phase is to prepare and implement a detailed baseline environmental plan and mining permit to mine on state mineral leases.
ARR is developing partnerships with various Wyoming-based businesses and entities to advance the development of a mine on state lands. The company believes such partnerships provide the shortest path to mine permits, maximising the value of Wyoming state resources.
The future work plans for 2024 are:
- JORC scoping study being prepared by Stantec;
- Test mine approval for bulk sample permits (aka licence to explore);
- Additional detailed metallurgical test-work for beneficiation, leaching and refining of rare earth oxides; and
- Options for Pilot Plant being studied.
The full technical report is available on the Halleck Creek tab on the company’s website.