Musensi Hill Rare Earth Elements Project, Tanzania

Amigo Resources PLC (LSE: AMGO) is pleased to provide an exploration update following the Company's earlier announcement on 1 July 2026 regarding the Musensi Hill Rare Earth Elements ("REE") Project in Tanzania.

Since the earlier announcement, the Company's geological team has completed an initial programme of systematic geological mapping, GPS-referenced rock sampling, structural observations, photographic documentation and geochemical screening across the project area.

The work has materially improved the Company's understanding of the geological setting at Musensi Hill and supports the interpretation of a multi-phase alkaline-carbonatite system hosted within granitic and granite-gneiss basement rocks.

Highlights

• Geological mapping has identified multiple rock types interpreted as components of an alkaline-carbonatite complex.
• Mapped lithologies include calcitic carbonatite, ferruginous carbonatite, carbonatite breccias and fragmental or tuffaceous carbonatite units.
• Extensive potassium feldspar-rich alteration has been observed in the surrounding granitic rocks and is interpreted as possible fenitisation associated with alkaline magmatic and hydrothermal activity.
• Geological sampling was completed using GPS-referenced locations, detailed field descriptions and photographic records.
• Initial analytical work was undertaken by the Geological Survey of Tanzania.
• The initial laboratory programme comprised major-oxide and selected trace-element XRF screening.
• Results include elevated potassium, calcium, phosphorus, strontium, rubidium, zirconium, iron and vanadium in selected samples.
• Several samples returned high strontium values, locally reaching approximately 7,000 ppm.
• Potassium oxide values of approximately 9% to 11.7% in several samples support the field interpretation of strong potassic alteration.
• Calcium oxide values of up to approximately 15.1% support the presence of carbonate-rich lithologies.
• Phosphorus pentoxide values locally reached approximately 7.29%, indicating phosphate enrichment in selected samples.
• The geological and geochemical information collected to date has been integrated into the Company's first working geological model for Musensi Hill.
• Priority areas have been identified for specialist REE analysis, mineralogical investigation, geophysical interpretation and future drill-target definition.

The geological programme and laboratory interpretation are summarised in the Company's Musensi Hill integrated exploration update.

Geological Programme

The initial field programme was undertaken to confirm the distribution of the principal lithologies, document geological relationships and collect representative material for laboratory investigation.

The Company's geologists completed systematic traverses across the project area and recorded:

• carbonatite and carbonate-rich rock exposures;
• potassium feldspar-rich altered granitic rocks;
• intrusive and brecciated textures;
• fragmental and tuffaceous lithologies;
• ferruginous weathering;
• carbonate veining;
• structural features and lithological contacts; and
• variations within the surrounding granitic and granite-gneiss basement.

Samples were collected from representative outcrops and assigned location information, geological descriptions and photographic records. The field programme was designed to establish an auditable geological and geochemical database to support future phases of advanced exploration and technical work, including geochemistry, mineralogy, and geophysics.

Initial Laboratory Results

Selected samples were submitted to the Geological Survey of Tanzania for major-oxide and selected trace-element XRF screening.

The Company emphasises that this initial analytical programme did not include a complete suite of rare earth elements and cannot be used to infer REE grade, continuity or economic potential.

The results are nevertheless considered geologically encouraging because they are consistent with several features observed during field mapping.

Potassic alteration

Several samples returned potassium oxide values of approximately 9% to 11.7%. These results are consistent with abundant potassium feldspar and support the field interpretation of strong potassic alteration in portions of the granitic host rocks.

The Company considers this alteration potentially significant because potassium-rich metasomatism may form part of a fenitic alteration halo developed around an alkaline-carbonatite intrusive system. This interpretation remains preliminary and requires confirmation through petrography and mineral chemistry.

Carbonate-rich lithologies

Calcium oxide values ranged up to approximately 15.1%, with selected samples returning values of approximately 13.5% to 15.1%.

These results support the field classification of carbonate-rich rocks identified during geological mapping, although additional mineralogical, petrographic and whole-rock studies are required to classify individual carbonatite phases conclusively and to determine whether any REE‑bearing minerals are present.

Phosphate enrichment

Phosphorus pentoxide values of approximately 2% to 3% were recorded in a number of samples, with one result reaching approximately 7.29%.

Phosphate enrichment may reflect the presence of apatite or other phosphate minerals commonly associated with alkaline and carbonatite geological environments. However, phosphate enrichment alone does not indicate REE grade or economic mineralisation.

Strontium

Several samples returned elevated strontium values, including results of approximately:

• 1,700 ppm;
• 1,800 ppm;
• 2,300 ppm;
• 4,100 ppm; and
• 7,000 ppm.

Elevated strontium is considered an important geochemical indicator in the evaluation of carbonate-rich and alkaline intrusive rocks. Elevated strontium values are supportive of the carbonatite model but do not indicate REE potential. These results provide further support for the Company's carbonatite-related exploration model.

Other geochemical observations

Selected samples also returned:

• rubidium values exceeding 500 ppm;
• zirconium values generally within approximately 400-900 ppm;
• iron oxide values ranging up to approximately 19%; and
• vanadium values commonly within approximately 300-600 ppm, with one anomalous result of approximately 2,600 ppm.

The elevated iron values are consistent with ferruginous lithologies and weathering observed in the field. The anomalous vanadium result will be re-analysed through repeat analysis and follow-up mineralogical work to determine its mineralogical host, such as magnetite or another iron-titanium oxide phase.

Gold values for all samples were below the reported detection limit of 0.003 g/t. Gold was not the target of the programme.

Integrated Geological Interpretation

The combined field and laboratory information supports a working interpretation in which Musensi Hill comprises a multi-phase alkaline-carbonatite system emplaced into older crystalline basement rocks. This interpretation is preliminary and subject to refinement as additional geological, mineralogical and geochemical data is acquired.

The principal elements of the current geological model include:

• multiple carbonate-rich intrusive phases;
• extensive potassium feldspar-rich alteration in the surrounding granitic rocks;
• carbonatite breccias and fragmental units;
• structurally controlled emplacement and fluid movement;
• carbonate veining and hydrothermal alteration; and
• ferruginous weathering developed over portions of the system.

The Company considers the consistency between geological mapping and the initial major-oxide and trace-element results to be encouraging. In particular, the association of elevated calcium, potassium, phosphorus and strontium supports continued evaluation of Musensi Hill as a carbonatite-related critical-minerals exploration target.

The current work does not establish the presence, grade, continuity or economic recoverability of REE mineralisation.

Next Phase of Exploration

The next phase is expected to include:

• complete REE analysis covering lanthanum through lutetium, together with yttrium;
• analysis for niobium, tantalum, thorium, uranium, barium and confirmatory strontium;
• whole-rock fusion ICP-MS or equivalent specialist analysis;
• petrographic examination and thin-section studies;
• X-ray diffraction mineral identification;
• scanning electron microscopy and mineral chemistry;
• detailed geological and structural mapping;
• systematic soil and rock geochemistry;
• quality-assurance and quality-control sampling;
• integration of geological and geophysical information;
• three-dimensional geological modelling; and
• definition of targets for a future first-pass drilling programme.

Priority will be given to samples and areas exhibiting coincident carbonate-rich lithologies, phosphate enrichment, elevated strontium, strong potassic alteration, brecciation and favourable structural settings.

Craig Ransley, Executive Chair of Amigo Resources PLC, commented:

"This first exploration update represents an important step in the systematic evaluation of Musensi Hill following our initial announcement of the project.

The work completed by our geological team has confirmed the presence of a complex geological environment comprising carbonate-rich rocks, fragmental and brecciated units, strong potassic alteration and encouraging carbonatite-related geochemical indicators.

The initial laboratory programme was designed as a geological screening exercise and did not include the complete rare earth element suite. It remains premature to draw any conclusions regarding REE grade, continuity or economic potential.

Nevertheless, the consistency between the field observations and the elevated calcium, potassium, phosphorus and strontium results provides a sound geological basis for advancing to specialist REE and mineralogical analysis.

Our immediate priority is to establish the mineral hosts, confirm the full REE distribution and refine the highest-priority targets, which will provide the preliminary information required to define the first-pass drilling locations."