Mount Ridley has commenced aircore drilling on the 30km long Mia-Marvin Zone at its namesake rare earths project in WA.

The program is targeting high silica-kaolin saprolite specifically as this may beneficiate through simple screening. It’s also mineralisation that may have similarities to REE deposits in China, Africa and elsewhere in Australia, the company says.

Mount Ridley Mines (ASX:MRD) has also reported assays from 87 aircore holes at Mia, with 62 returning TREO above 500ppm, including best results of:

  • 6m at 6,648ppm TREO from 57m (containing 2,726ppm (41%) MagREO) including 1m at 28,831ppm (2.88%) TREO in fresh rock at the end of the hole (MRAC1188);
  • 29m at 1,748ppm TREO from 30m (containing 407ppm (23%) MagREO) including 9m at 2,821ppm TREO from 39m (MRAC1184); and
  • 8m at 3,272ppm TREO from 9m (containing 1,026ppm (31%) MagREO) including 1m at 9,329ppm (0.93%) TREO from 12m (MRAC1180). 

MRAC1188 returning 2.88% TREO is the highest-grade TREO intersection recorded to date, and the company has drilled additional holes at this locality and commenced a petrographic study to determine whether this is an occurrence of primary mineralisation.

Focus on high-value magnet rare earths

Magnetic rare earths have also been flagged at the Jody prospect, which recently returned results of 15m at 1,284ppm TREO from 24m (containing 308ppm (24%) MagREO) and 11m at 1,550ppm TREO from 33m (containing 328ppm (21%) MagREO).

This is particularly notable because they are the rare earth elements widely used in wind turbines, electric vehicles, guidance systems on aircraft and missiles, and consumer electronics.

“Within 12 months of our first REE drilling program, the company has commenced mineral resource drilling at the Mia and Marvin targets, a contiguous trend of mineralisation which is 30km long and 4km wide,” chairman Peter Christie said.

“These prospects were selected as our priority by using a number of criteria, including the potential for beneficiation, clay type, TREO grade, depth of cover and proportion of high value magnet rare earths.”

The company has already prepared composites for metallurgical testing from diamond drilling late last year, with highlights including:

  • Mia: MRDD044: 10m at 866ppm TREO from 26m;
  • Butch: MRDD038: 46.00m at 1,558ppm TREO from 31m;
  • Winstons: MRDD036: 17.60m at 1,643ppm TREO from 41m; and
  • Vincent: MRDD029: 9.20m at 2,338ppm TREO from 30m.

Next steps include infill drilling

Subject to results from the program, infill drilling of the same 25km central Mia area is planned to bring the drilling density down to a 400m x 400m grid pattern.

A POW for this work is approved subject to completing heritage and flora surveys, booked for early April 2023.

Mount Ridley has also applied for (and in some cases been approved for) separate POWs to drill up to 9km north and up to 10km south of the central Mia Prospect, as far south as the Marvin Prospect, subject to completing heritage and flora surveys.




This article was developed in collaboration with Mount Ridley Mines (ASX:MRD), 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.