Red Mountain Mining confirms sought-after heavy rare earths at Mt Mansbridge

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By Robin Bromby - 
Red Mountain ASX RMX gold copper heavy rare earths nickel cobalt PGE sulphides

Red Mountain Mining is drilling for gold and base metals at Mt Maitland, while field work has begun at Mt Mansbridge which is prospective for HREE, nickel-copper-cobalt and PGE.


Red Mountain Mining (ASX: RMX) confirms drilling at its Mt Mansbridge project in Western Australia has shown the presence of the valuable heavy rare earth elements (HREE), including the high-priced dysprosium and terbium.

This breakthrough comes amid a background of tightening Chinese control of rare earths, now being put into effect by the merger of the three producers in China — China Minmetals Rare Earth, Chinalco Rare Earth & Metals and China Southern Rare Earth Group. 

Analysts are expecting that China will hike prices as demand grows for electric vehicles, for which HREE are vital. 

Red Mountain says assays from the drilling at Solo prospect returned 5m at 0.316% total rare earth oxides, with an average 66.62% HREO. 

Dysprosium the star of the assay result

While the usual lower-priced elements are present — yttrium accounts for 43.15% of the rare earths distribution and cerium 15.03% — dysprosium made up an impressive 5.65% and terbium 0.97%. 

Dysprosium is a key element of alloys for permanent magnets used in motors, electric vehicles and wind turbines.

In addition, the battery metals neodymium and praseodymium between them accounted for 12.9%, while there were small weightings of samarium, europium (the HREE that enables the colour red on electronic and television screens), gadolinium, holmium, erbium, thulium, ytterbium and lutetium.

The remaining assays from the drilling will be reported in the current quarter.

More drilling will take place at Mt Mansfield in the second quarter of the year, following the end of the wet season.

Access tracks have been completed and heritage clearances have been received.

Rare earths overlooked during previous exploration

The rare earth tenements lie about 40km from Northern Minerals’ (ASX: NTU) flagship Browns Range project in the Eastern Kimberley region, where the HREE dominate the mineralisation.

Red Mountain’s project area has been subject to exploration activities since the 1970s, primarily for uranium, gold and diamonds, which were all unsuccessful.

However, the presence of the rare earth elements’ mineralisation had been overlooked and Red Mountain has previously stated that it sees the opportunity to capitalise on this and determine whether there is an economically viable concentration of rare earth elements.