Mount Ridley’s re-assay work turns up ‘Makuutu-like’ rare earth grades

Barely days after unveiling the rare earths potential of its namesake project, Mount Ridley has now extended the prospective horizons to more than 25km strike.

This follows the re-assay of a further 160 samples from 59 drill holes that were drilled from 2017 to 2019 at the Winston’s and Keith’s prospects, which returned grades such as 6m at 2,005 parts per million (ppm) total rare earth oxides (TREO) and 5m at 3,949ppm at the two prospects respectively.

Mount Ridley Mines (ASX:MRD) notes that the grades compare favourably to Ionic Rare Earth’s Makuutu project in Uganda, which has an inferred and indicated resource of 78.6 million tonnes grading 840ppm TREO.

It has now started material characterisation and rare earth elements extraction tests that includes a program of partial leach analyses and mineral identification using microXRF.

“The identification of relatively shallow REE accumulations within the company’s extensive land holding was the result of a re-examination of previous drilling data at the Mount Ridley project over the previous five years,” chairman Peter Christie.

“We now have an interesting REE project on our hands and while it is early days in our technical analysis, the preliminary TREO grades and lateral extent of mineralisation would seem to indicate a rare earth project worthy of detailed investigation.”

Mineralisation at Mount Ridley is believed to be hosted in ionic adsorption clays that are rarely found outside of China and are considered to be some of the cheapest and most readily accessible sources of heavy rare earths.

Mount Ridley prospects

The latest re-assay results have extended REE mineralisation at the Winston’s prospect by at least 1km in a north-easterly direction and also demonstrate continuity of mineralisation over the intervening 4km between the now-merged Winston’s and Lake Prospects.

Winston’s now has a strike length of at least 10km and a width exceeding 1km.

Previous aircore drilling was generally collared on a 500m by 80m grid, a reconnaissance pattern which is not suitable for JORC estimations.

As such, Mount Ridley is planning to carry out infill and extensional drilling at the prospect.

Over at Keith’s, REE mineralisation has been defined to more than 4km long and 1km wide with drilling carried out over a 500m by 100m grid with one infill pattern drilled on a 100m by 25m grid.

Upcoming work

The company noted that the partial leach analysis will study the extractability of RE element and take into solution the ionic adsorption clay-hosted RE elements as well as REE in colloidal clay phases, but not refractory minerals such as xenotime and monazite.

Planning is also underway for an extensive aircore drill program that will redrill holes that terminated in REE, extending drilling traverses where mineralisation remains open, and reconnaissance drilling to test other targets.

Sonic drilling is being considered to recover intact core from poorly consolidated rocks for regolith studies, geotechnical and metallurgical testing, and to test the quality of some of the significantly mineralised, earlier, aircore holes.

Updates to existing flora, and fauna surveys have been initiated, and Heritage Protection Surveys are being reviewed prior to updates that may be required.

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.