Ark Mines (ASX:AHK) has completed stage three resource expansion drilling at its Sandy Mitchell Rare Earths Project in North Queensland, logging mineral sands from surface in all 218 holes.
The program comprised 2,330.5m of drilling across 18 lines, with an average hole depth of 10.7m and an average mineral sands thickness of around 10m.
Stage three drilling covered a further 1,924.4 hectares beyond mining lease ML 100409 and into exploration permit EPM 28013. Combined drilling across all three stages now covers 2,328.5 hectares, with both tenements held 100% by Ark.
Assays returned rare earth, heavy mineral, and industrial mineral values in every metre sampled. Ark says the results are consistent with the first two drilling stages, which informed the existing measured mineral resource estimate (MRE).
Total heavy minerals averaged 3.5% across stage three and 3.03% across all three programs. The assemblage includes monazite, xenotime, zircon, rutile, leucoxene, ilmenite, and garnet.
Total commercial minerals, which also include muscovite and biotite, averaged 16.9% across stage three and 15.5% across the combined drilling.
Monazite and xenotime averaged a combined 1,413.5 parts per million (ppm) during stage three, while total rare earth oxides plus yttrium averaged 361.5ppm and reached a maximum of 1,433.6ppm. Concurrently, zircon averaged 658.7ppm and returned a maximum value of 4,534.5ppm.
Executive Director Ben Emery says the program was designed to increase the area available for resource modelling.
“Mineralisation logged and assayed from surface, right across the program area, has been in line with our expectations and with the design of the expansion program,” Emery says.
“We look forward to incorporating these results into an updated mineral resource estimate and our forthcoming Prefeasibility Study.”
Sandy Mitchell currently hosts a measured MRE of 71.8 million tonnes @ 1,730ppm monazite equivalent (MzEq), reported above a 700ppm MzEq cut-off grade.
The stage three holes were drilled on a staggered 280m by 280m grid adjacent to the existing resource. Ark says the spacing was selected to target a predominantly indicated classification, although the final classification will depend on the resource modelling.
Consultant HGS Australia is combining the new results with data from the first two stages to prepare an updated MRE, which Ark expects to release in September.
The revised estimate and ongoing metallurgical test work by IHC Mining will inform an updated Scoping Study and a Prefeasibility Study targeted for 2027.
Sandy Mitchell also has an exploration target of 1.32–1.58 billion tonnes @ 1,290–1,900ppm MzEq, excluding the existing resource. Ark notes that the target is conceptual, and further exploration is required to determine whether it can be converted into a mineral resource.
Ark Mines is an Australian critical minerals explorer and developer focused on its wholly owned Sandy Mitchell Project in North Queensland.
Write to France Pinzon at Mining.com.au
Images: Ark Mines
