Mr. Gilbert Clark reports

MERIDIAN SMELTER TESTS DELIVER HIGH QUALITY BLISTER COPPER FROM CABACAL COPPER CONCENTRATES

The smelting of Cabacal copper sulphide has produced high-quality blister copper grading 98.9 per cent copper, 95.2 grams per tonne gold and 387.6 grams per tonne silver (Table 1). The blister copper was produced from a concentrate sample produced from Meridian Mining PLC's Cabacal copper-gold-silver project in Mato Grosso, Brazil. It was processed in laboratory-scale smelting and converting tests at Kingston Process Metallurgy (KPM) in Ontario, Canada.

Highlights:

• Exceptional quality of Cabacal's copper concentrates confirmed in smelter test with high-grade, high-quality blister copper produced;
• Laboratory-scale smelting and converting tests resulted in:
  • Copper of 98.9-per-cent purity:
    • Precious metals at 95.2 g/t gold and at 387.6 g/t silver;
• Cabacal's blister copper's impurity levels assayed better than industry average for high-quality anode copper;
• The high copper grades, significant gold and silver credits and lack of impurities in Cabacal's copper concentrates are expected to make them highly sought after by the world's copper smelters;
• Meridian continues to engage in offtake discussions with a range of potential counterparties.

Cabacal's blister copper contained very low minor-element impurity levels, outperforming typical industry anode copper, while maintaining the residual sulphur levels targeted for the laboratory smelting and converting test program. The associated high recoveries of copper, gold and silver in the smelting stage demonstrate that Cabacal's copper concentrates convert efficiently into high-quality copper blister under smelting conditions representative of commercial operations.

Gilbert Clark, chief executive officer, commented: "These results take the marketability and value of Cabacal's copper concentrates to the next level; a tremendous confirmation of the product. Cabacal's DFS [definitive feasibility study] is advancing towards completion and project finance preparation is well advanced. We are positioning Cabacal to deliver one of the most sought-after high-grade, clean copper concentrates in the market with high gold and silver payable credits, exceptionally low impurities, and the sulphur content required for acid production. This is a strong negotiating position as we move into offtake discussions for a copper-gold mine that will go for over 10 years and a belt that could potentially be in production for decades to come. These results are another demonstration of why Meridian is developing one of the most prospective copper-gold VMS-hosted land packages in South America."

Cabacal copper concentrate smelting test

As part of Cabacal's DFS program, the company has completed, laboratory-scale, smelter characteristic test work on copper sulphide concentrates containing gold and silver, sourced from ROM-grade (run of mine) ore samples. The objective of the test was to blow high-grade matte (approximately 62 per cent Cu) to blister copper to demonstrate that Cabacal's low-impurity copper plus gold-silver sulphides exhibit superior smelting performance and could produce a high-grade, high-quality copper blister product. The results met the company's expectations. They confirm that Cabacal's copper concentrates possess excellent smelting characteristics and, if used as direct smelter feed, will produce very high-purity copper anodes. In the more likely commercial scenario, the concentrate may be used as a premium blending feedstock to upgrade third party lower-quality copper concentrates (those that have lower copper content or are precious metal poor or have high penalty elements), helping smelters meet minimum feed specifications and improve overall furnace performance.

Cabacal's future copper concentrates are expected to generate strong interest from smelter groups and/or trading houses seeking to secure high-quality, long-term supply. Current discussions are continuing with a range of potential offtakers for Cabacal copper concentrate supply. In a market where copper concentrate demand exceeds supply, treatment charges/refining charges have fallen to historic lows and where deductions for gold and silver continue to decline. Cabacal, with its plus-10-year production profile of uncontracted high-quality copper concentrates, provides a highly attractive stable platform for future smelter feed. Samples of the blister (or sawing particles) and its data sheet will be made available as part of Cabacal's project finance and/or offake discussions.

The quality of the Cabacal copper concentrate and produced blister copper is illustrated in the table below.

Inspection of Table 1 shows that there was effective separation of the copper metal from the slag in the laboratory crucible. It is noted that the precious metal assays in Table 1 reflect their amounts in a smaller mass of copper. Commercially, matte would be fully converted to copper, resulting in a larger mass of copper that would have a commensurate reduction in the precious metal grade.

In 2025, the mini pilot facility at the SGS laboratory in Lakefield, Ont., Canada, processed approximately 1.6 tonnes of Cabacal ROM grade drill core averaging 0.50 per cent Cu, 0.92 g/t Au and 1.60 g/t Ag, producing a copper concentrate hosting gold and silver, as well as a separate gravity gold concentrate. The pilot test was preceded by a series of laboratory milling and flotation tests. Samples of the copper concentrate were then shipped to KPM for smelting tests.

For ease of handling at the laboratory scale, the smelting and converting tests at KPM were carried out in four phases broadly resembling commercial smelting and converting (with the exception that slag was not recycled for metal recovery and blister copper contained residual sulphur). The Factsage software was used to compute the required blowing rate, time of blowing and flux addition.

The stages are as follows:

1. Smelting the copper concentrate to a low-grade matte at 1,250 C typically 26.3 per cent Cu, 38.7 per cent Fe and 28.5 per cent S at a high copper recovery (95 per cent) and a low copper slag (0.37 per cent Cu);
2. Upon cooling, the matte contained in a crucible at 1,230 C was:
   1. Firstly, upgraded to about 45 per cent Cu matte by lancing with gas at 30 per cent O2 (oxygen) and 70 per cent Ar (argon) while adding SiO2 (silicon dioxide) flux in proportion to the blowing rate;
   2. Secondly upgraded to 62 per cent Cu using a similar method;
3. The 62 per cent Cu matte was then converted to high-sulphur blister copper by lancing with 30 per cent O2/70 per cent Ar gas and adding SiO2 flux until the high-grade matte in the crucible was estimated at 78 per cent Cu; lancing then continued; blowing was deliberately stopped when the molten blister copper was estimated to contain about 1.0 per cent S, avoiding overblowing of the melt.

Assaying methods

The assaying for gold was done by SGS Lakefield in Peterborough, Ont., and the trace elements were analyzed by Kingston Process Metallurgy at Kingston, Ont. Methods used by SGS Lakefield GC_FAA35V10 was utilized for gold analysis, which is a lead oxide fusion.

Kingston Process Metallurgy (KPM) used the following procedure for the determination of metals and minor elements in copper and matte: Each sample was representatively sampled and prepared for analysis by sodium peroxide fusion followed by HCl digestion. The digestate samples were analyzed by ICP-OES under three dilution factors, with matrix matching. Internal standardization was used for quality control. Seven certified reference materials containing the elements of interest at or below the reported detection limits were prepared and analyzed by the same procedure. KPM analyzed the silver using acid digestion of the blister copper with hydrochloric and nitric acids in the mass ratio 3:1, followed by an ICP-OES finish.

Qualified person statement

Dr. Norm Lotter of Flowsheets Metallurgical Consulting Inc., a qualified person as defined by National Instrument 43-101, has reviewed, verified and approved the technical information in this news release.

About Meridian Mining PLC

Meridian Mining is focused on:

• The development and exploration of the advanced-stage Cabacal VMS (volcanogenic massive sulphide) gold-copper project;
• Expanding the initial resource inventory at the Santa Helena area through extension of Santa Helena Central and new discoveries;
• Regional-scale exploration of the Cabacal VMS belt to expand the Cabacal hub strategy;
• Exploration in the Jauru and Araputanga greenstone belts (the above all located in the state of Mato Grosso, Brazil).

The prefeasibility study technical report dated March 31, 2025, entitled "Cabacal Gold-Copper Project NI 43-101 Technical Report and Pre-feasibility Study" outlines a base-case after-tax net present value (discounted at 5 per cent) of $984-million (U.S.) and 61.2-per-cent internal rate of return from a preproduction capital cost of $248-million, leading to capital repayment in 17 months (assuming metals price scenario of $2,119 (U.S.) per ounce of gold, $4.16 (U.S.) per pound of copper and $26.89 (U.S.) per ounce of silver). Cabacal has a low all-in-sustaining cost of $742 (U.S.) per ounce gold equivalent and production profile of 141,000 ounces of gold equivalent life of mine, driven by high metallurgical recovery, a low life-of-mine strip ratio of 2.3:1 and the low operating cost environment of Brazil.

The Cabacal mineral reserve estimate in the PFS consists of proven and probable reserves of 41.7 million tonnes at 0.63 g/t gold, 0.44 per cent copper and 1.64 g/t silver (at a cut-off grade of 0.25 g/t gold equivalent).

Readers are encouraged to read the PFS technical report in its entirety. The PFS technical report may be found under the company's profile on SEDAR+ and on the company's website.

The PFS technical report was prepared for the company by Tommaso Roberto Raponi, PEng, principal metallurgist with Ausenco Engineering Canada ULC; Scott Elfen, PE, global lead, geotechnical and civil services, with Ausenco Engineering Canada ULC; John Anthony McCartney, CGeol, Ausenco Chile Ltda.; Porfirio Cabaleiro Rodriguez (engineer geologist FAIG) of GE21 Consultoria Mineral; Leonardo Soares (BSc Geo, MAIG), senior geological consultant of GE21 Consultoria Mineral; Norman Lotter (mineral processing engineer, PEng) of Flowsheets Metallurgical Consulting Inc.; and Juliano Felix de Lima (engineer geologist MAIG) of GE21 Consultoria Mineral.

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