Heavy Rare Earths Enrichment Confirmed
Altona Rare Earths PLC has announced significant assay results from its 2025 drilling campaign at Monte Muambe, confirming heavy rare earths enrichment associated with fluorspar, with intercepts up to 30m at 2,677ppm HREO and HREO/TREO ratios ranging from 21% to 77%. Notably, xenotime, a heavy rare earth mineral, was identified for the first time, suggesting a potential pathway to producing a marketable HREE concentrate as a by-product of fluorspar processing, which could materially enhance project economics. Individual dysprosium grades reached up to 567ppm Dy2O3, a highly sought-after element for high-tech and defence applications. The company is now assessing whether a dedicated HREE mineral resource estimate is warranted.
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Altona (LSE:REE)(OTCQB:ANRCF), the Africa focused critical minerals exploration and development company, is pleased to announce the receipt of rare earths assay results from its 2025 drilling campaign at Monte Muambe.
Highlights
All rare earths assay results from the 2025 drilling programme are now in hand, and geological modelling of heavy rare earths ("HREE") mineralization associated to fluorspar has started.
Wide significant intercepts have been observed, with up to 30m at 2,677ppm HREO(1), and HREO/TREO(2) ratios ranging from 21% to 77%, confirming HREE enrichment is widespread across the Fluorite Zone.
Up to 567ppm dysprosium oxide in individual drilling intercepts.
Xenotime, a HREE mineral, identified for the first time at Monte Muambe, provides a potential pathway to producing a marketable HREE concentrate as a by-product of fluorspar processing.
Received results are from samples from diamond drilling and reverse circulation drilling holes at the Fluorite Zone, Southern Extension, Kudu and Python. All drilling samples were reassayed for rare earths following the identification of HREE enrichment in association to fluorspar announced on 14 April 2026.
Individual dysprosium grades reach up to 567ppm Dy2O3, and the significant intercepts weighted average is 172 ppm Dy2O3, which is with the usual range for HREE projects. Dysprosium is a highly sought-after HREE used in a wide range of high technology and defence applications, and the main value driver for this mineralisation. Significant intercepts are listed in the table below.
Mineralogy results from a representative fluorspar ore sample currently undergoing metallurgical testing indicate the presence of xenotime, a HREE mineral reported for the first time at Monte Muambe and absent from the main rare earths resource (which is primarily a neodymium and praseodymium resource). Critically, this suggests that a HREE concentrate could potentially be recovered during fluorspar processing at materially lower incremental cost than a standalone HREE operation, which could significantly enhance the overall fluorspar project economics.
| Hole Number | From (m) | Length (m) | HREO ppm | HREO/TREO % |
|---|---|---|---|---|
| MM127 | 25 | 9 | 3,540 | 59% |
| MM130 | 30 | 15 | 1,996 | 36% |
| MM131 | 29 | 12 | 3,223 | 77% |
| MM145 | 13 | 11 | 1,371 | 24% |
| MM146 | 11 | 16 | 2,015 | 49% |
| MM148 | 12 | 14 | 1,848 | 21% |
| MM154 | 4 | 14 | 1,912 | 26% |
| MM156 | 0 | 30 | 2,677 | 57% |
| MM161 | 13 | 11 | 1,359 | 41% |
| MM163 | 1 | 5 | 2,404 | 65% |
| MM165 | 0 | 18 | 1,264 | 40% |
| MM169 | 71 | 4 | 2,916 | 47% |
| MM173 | 63 | 13 | 1,538 | 22% |
| MM183 | 26 | 7 | 1,755 | 23% |
Next steps
Subject to the outcome of ongoing geological modelling, the Company expects to determine in the coming weeks whether a dedicated HREE mineral resource estimate is warranted.
Cedric Simonet, CEO, commented: "These results are highly significant. Widespread HREE enrichment in association with fluorspar, combined with the first identification of xenotime at Monte Muambe, opens a compelling pathway to HREE production as a by-product of our fluorspar operation. If confirmed by ongoing metallurgical work and geological modelling, this would meaningfully enhance the project's value proposition and add a fourth strategic commodity to Monte Muambe's already exceptional multi-commodity profile."
- HREO is the sum of all rare earth elements from samarium to yttrium, expressed as oxide.
- TREO is the sum of all rare earth elements from lanthanum to yttrium, expressed as oxide.
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Altona Rare Earths Plc
Cédric Simonet, CEO +44 (0) 7778 866 108 (cs@altonare.com)
Louise Adrian, CFO +44 (0) 7721 492 922 (la@altonare.com)
Strand Hanson (Financial Adviser) +44 (0) 20 7409 3494
Christopher Raggett
Imogen Ellis
Zeus Capital (Corporate Broker) +44 (0) 20 3829 5000
Simon Johnson
James Hornigold
About Altona Rare Earths Plc
Altona Rare Earths Plc (LSE:REE)(OTCQB:ANRF) is a London Main Market-listed exploration and development company focused on unlocking the value of critical raw materials across Africa. The Company is pursuing a diversified strategy, targeting assets with potential for near-term monetisation alongside long-term growth.
The multi-commodity Monte Muambe Project in northwest Mozambique is a highly prospective tenement hosting rare earths, fluorspar, and gallium mineralisation. Published JORC mineral resource estimates include:
- 13.6Mt at 2.42% TREO
- 3.48Mt at 20.6% CaF2
- 11.73Mt at 54.7g/t Ga2O3
The project is held under a 25-year mining licence and has received US Government support in the form of a US$ 1.875 million grant from USTDA to advance the rare earths component through the prefeasibility stage.
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