London-listed Altona Rare Earths has identified heavy rare earths element enrichment in the Monte Muambe fluorspar and gallium ore, a possible additional value driver for this multicommodity project, in Mozambique.

As part of the ongoing fluorspar and gallium mineral resource estimate (MRE) preparation, the company has assayed control samples for a broad range of trace elements, including rare earths.

Assay results show that these samples contain about 3 200 parts per million (ppm) total rare earths oxide (TREO) and 1 300 ppm heavy rare earths oxide (HREO).

This corresponds to an HREO/TREO ratio of 40%, significantly higher than that of the Monte Muambe rare earths deposit (Target 1 and Target 4), which hosts a Joint Ore Reserves Committee-compliant MRE of 13.6-million tons at 2.42% TREO and is predominantly enriched in light rare earths such as neodymium and praseodymium, with a HREO/TREO ratio of about 5%, Altona points out.

Heavy rare earths, including dysprosium, terbium and yttrium, are classified as critical minerals owing to their essential role in enhancing the performance of neodymium magnets, particularly those used in high-performance applications.

They are also key components in advanced electronics, medical devices and data storage systems, Altona explains.

The company adds that high-performance military technologies are heavily reliant on heavy rare earths, with no substitution options.

Heavy rare earths production is currently concentrated in China.

Compared to light rare earths, heavy rare earths are significantly scarcer, carry a higher structural supply risk, and are therefore of higher strategic importance, Altona notes.

While further work is required to determine the extent, distribution and recoverability of heavy rare earths from the fluorspar ore, their presence highlights the potential for an additional high-value by-product, alongside gallium, within the Monte Muambe fluorspar project, Altona highlights.

Altona has initiated workstreams of mineralogical studies to identify the host phases of the heavy rare earths; updated fluorspar metallurgical testing workflow to assess the heavy rare earths deportment during fluorspar flotation and evaluate the potential for integration into the fluorspar processing flowsheet; and expanded assaying of samples from the 2025 fluorspar drilling campaign to include rare earths, with a view to potentially incorporating heavy rare earths into a future MRE update.

It assures shareholders that this additional work will not impact the timeline for publication of the fluorspar and gallium MRE.

Any inclusion of heavy rare earths in the MRE will be considered in a subsequent update once sufficient data has been generated, the company adds.

“The identification of a heavy rare earth enrichment within the Monte Muambe fluorspar ore is an exciting development, given the scarcity and strategic importance of these elements, and will potentially materialise as an additional value driver to this project,” says CEO Cedric Simonet. 

“Our immediate focus is to better understand the mineralogical characteristics and metallurgical behaviour of these elements, with a view to determining whether they can be economically recovered as part of the fluorspar processing flowsheet.

“If successful, this could further enhance the project's value proposition and strategic relevance, particularly in the light of our ongoing engagement with the US government and with participants in the US rare earths supply chain,” he adds.