17 September 2025

ALTONA RARE EARTHS PLC

("Altona" or the "Company")

JORC FLUORSPAR RESOURCE TO INCLUDE GALLIUM ESTIMATE

Altona Rare Earths PLC (LSE: REE), a resource exploration and development company focused on critical raw materials in Africa, is pleased to provide an update on Monte Muambe's fluorspar and gallium drilling and resource estimate plans.

Highlights

·      Metallurgy results on a sample of gallium-bearing fluorspar ore confirmed that the flotation process will lead to a separation of fluorspar (in the concentrate) and gallium (in the process tailings), providing a potential two step pathway to recover both fluorspar and gallium.

·     Considering the affinity between fluorspar and gallium, the planned JORC Mineral Resource Estimate ("MRE"), expected by the end of 2025, will report both commodities.

·    Drilling of hole MM111, which is expected to intercept both fluorspar and gallium mineralisation, has started.

·    280 soil samples have been sent to the laboratory in South Africa for fluorine assays. Results are expected to lead to the discovery of additional fluorspar resources which will be included in the drilling plan.

Gallium Metallurgical Behaviour During Fluorspar Recovery Confirmed

Altona is pleased to announce that it has received from SGS Lakefields results from metallurgical testing of a fluorspar ore sample containing gallium. The results confirm that during the process of fluorspar recovery by flotation, gallium is correlated with aluminum (contained in feldspar) and negatively correlated with fluorspar. This behavior is consistent with the Electronic MicroProbe Analysis results announced by the Company on 4 September 2025.

These results provide further comfort that, during fluorspar recovery via flotation, gallium will report into the tailings, hence providing a potential two step pathway to recover both fluorspar and gallium. Gallium recovery from the fluorspar tailings will be tested as part of advanced metallurgical studies for the production of commercial grade acid-spar.

Fluorspar Resource Definition Strategy Updated to Include Gallium

Altona is pleased to announce that, following its announcement of 4 September 2025, the Monte Muambe resource drilling programme has started with hole MM111. This hole is designed to intersect both high-grade fluorspar ore and adjacent low-grade fluorspar ore containing gallium, which will help understand the geometry, size and grade of both fluorspar and gallium mineralisation.

The initial drilling programme of 2,000 meters of diamond and reverse circulation drilling is designed to support the preparation of a fresh MRE, provide representative samples for advanced metallurgy, and allow the gathering of more geological data on associated gallium mineralisation.

Considering the proximity between fluorspar mineralisation and gallium mineralisation, as well as the separation and recovery pathway provided by mineralogy and metallurgy results obtained so far, the Company is pleased to announce that, in addition to fluorspar, a gallium MRE will also be reported.

The drilling programme is expected to last 2 months with the MRE published by the end of 2025.

Soil Samples Sent for Assay

280 soil samples collected earlier this year were sent to SGS South Africa for fluorine assay. The samples were selected on the basis of their high gallium content (over 60ppm) as this chemical element has previously proven to be a reliable pathfinder for fluorspar. The results of these assays are expected to lead to the discovery of additional fluorspar resources at Monte Muambe.

Cédric Simonet, CEO of Altona, commented:

"I am very pleased with the progress made in understanding gallium occurrences at Monte Muambe which allowed us to pinpoint a close geological association between gallium and fluorspar, but also a pathway to separate both minerals during fluorspar recovery. The results we have obtained so far now justify reporting gallium in the upcoming JORC fluorspar MRE. This will allow Altona to quantify this commodity, and to substantially increase the value of this asset for the Company's shareholders."

This announcement contains information which, prior to its disclosure, was inside information as stipulated under Regulation 11 of the Market Abuse (Amendment) (EU Exit) Regulations 2019/310 (as amended).

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Altona Rare Earths Plc

Cédric Simonet, CEO                                                                               +44 (0) 7778 866 108

Louise Adrian, CFO                                                                                  +44 (0) 7721 492 922

Strand Hanson Limited (Financial Adviser)                               +44 (0) 20 7409 3494

Christopher Raggett

Imogen Ellis

Oberon Capital (Corporate Broker)                                              +44 (0) 20 3179 5300

Nick Lovering

Adam Pollock

Aimee McCusker

About Altona Rare Earths Plc

Altona Rare Earths Plc (ticker: REE) 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. Since acquiring the project in June 2021, Altona has drilled over 7,800 metres, delivering a maiden JORC Mineral Resource Estimate of 13.6Mt at 2.42% TREO, secured a 25-year mining licence (granted December 2024), and published a Competent Person Report and scoping study for the rare earths component of the project (October 2023). The Company is actively seeking a strategic downstream rare earths partner to advance the project through the prefeasibility stage.

In parallel, Altona is progressing plans to fast-track the development of high-grade fluorspar veins identified along the western and southern margins of Monte Muambe, with a targeted production of 50,000 tonnes per annum of acid-grade fluorspar over a minimum 12-year mine life. Acid-grade fluorspar is a key input in a wide range of applications, including hydrofluoric acid and lithium battery electrolyte production, placing Altona in a strong position to supply this critical material.

The discovery of gallium mineralisation, with grades up to 550 g/t identified to date, adds further value to Monte Muambe. The Company is undertaking mineralogical and metallurgical studies to assess the potential for gallium production.

Altona's diversified portfolio also includes the Sesana Copper-Silver Project in Botswana, strategically located just 25 km from MMG's Khoemacau Zone 5 copper-silver mine. Situated on a recognised regional contact zone for copper deposits, Sesana represents a compelling exploration opportunity aligned with Altona's growth strategy.

With a unique combination of critical raw materials projects, Altona is well positioned to contribute to the global supply of highly sought commodities essential for clean energy, high technology, defence and industrial applications.

The Company and the Board remain actively focused on identifying and evaluating additional projects that align with our investment profile and strategic objectives, leveraging our extensive network and combined industry experience to uncover compelling opportunities that can drive long-term growth.

Competent Person Statement

The information in this RNS that relates to geology and exploration results is based on information compiled and/or reviewed by Cédric Simonet, who is a Member of European Geologist Federation (Eur. Geol. #739). Cédric Simonet is the Chief Executive Officer and a Director of the Company. He has sufficient experience which is relevant to the styles of mineralisation and type of deposit under consideration and the activity which he is undertaking to qualify as a Competent Person in terms of the 2012 Edition of the Australian Code for the Reporting of Exploration Results, Mineral Resources and Ore Reserves. Cédric Simonet consents to the inclusion in the RNS of the matters based on his information in the form and contest in which it appears.