Mount Ridley’s big push into rare earths drilling as its namesake project appears to be paying off with the return of a project-high intersection of 9m at 9,523ppm TREO at the Mia prospect.

The intersection, which is contained within a broader 36m interval at 4,398 parts per million (ppm) total rare earth oxides (TREO) from 15m to end of hole, is just one of several highly enriched REE intersections near a series of parallel, approximately linear magnetic ‘ridges’ seen in aeromagnetic imagery over a strike length of more than 16km.

While the results are undoubtedly a positive in Mount Ridley Mines’ (ASX:MRD) search for clay-hosted REE mineralisation, there is also potential for other sources of REEs with the company flagging that the high-grade intersections might be due to a nearby primary source of REEs in fresh rock.

“The company has completed over 800 holes or 36,000m of drilling, generating a tremendous amount of REE geochemical data that our geoscientists are working through,” chairman Peter Christie said.

“As drilling advanced at the Mia Prospect, patterns in aeromagnetic imagery were noticed that correlate with high-grade intersections of clay-hosted mineralisation, which may represent a second style of REE mineralisation in underlying basement rocks.

“We have fast tracked petrographic evaluations of samples of fresh REE-enriched Felsic rocks from the observed magnetic ‘ridges’ which could be the source of the REEs now hosted in the overlying clay. Perhaps what we are seeing is a second style of mineralisation more akin to a ‘hard-rock’ REE deposit.”

REE hunt progressing

The company noted that assays from aircore drilling for REEs are flowing through with all results expected by the end of May.

Beneficiation testwork is also progressing well with most samples screened and in the process of being filtered before the fine fraction is tested by the ANSTO, IMO and Simulus laboratories.

Additionally, Aboriginal Heritage Protection surveys are advancing, with a drone survey in progress while spring flora surveys are scheduled for priority drilling areas at the contiguous Mia and Marvin prospects.

These targets take into consideration the location of the magnetic ‘ridges’ evident in aeromagnetic imagery.

Mount Ridley has also received Programme of Work approvals from the state’s Department of Mines, Industry Regulation and Safety – subject to completing heritage and flora surveys – to drill up to 9km north and 10km south of the central Mia prospect area and as far south as the Marvin prospect.

These include provisions to progressively infill the drilling grid in areas to a 400m by 400m grid targeting high silica-kaolin saprolite, which may be similar to REE deposits in China, Africa and elsewhere in Australia that may be amenable to beneficiation through simple screening.

Planned reverse circulation drilling will test for REE mineralisation below the clay-zone REE intersections that are coincident with the magnetic ‘ridges’.




This article was developed in collaboration with Mount Ridley 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.