Meridian Updates Resources for Cabaçal and Santa Helena Central Deposits

2026-01-20

TSX - Toronto Stock Exchange · Gold · Copper · Silver · Zinc · Lead · Manganese · Iron · Tin · United Kingdom

Highlights:

Meridian announces Measured and Indicated (“M&I”) resources for Cabaçal as part of initial workstream towards its definitive feasibility study;Cabaçal mine’s Au-Cu-Ag open-pittable resource expanded;

— M&I: 70.1Mt @ 0.6g/t Au, 0.3% Cu, 1.3g/t Ag;

— Metal increases of 39.2% for Au, 14.2% for Cu and 19.3% for Ag;

— Mineralization remains open down dip;

Meridian reports M&I resources for the Santa Helena Central deposit;Santa Helena Central’s maiden open-pittable Au-Cu-Ag-Zn-Pb resource declared;

— M&I: 5.3Mt @ 0.6g/t Au, 0.4% Cu, 15.5g/t Ag, 1.9% Zn & 0.4% Pb;

— Resource remains open in all directions;

The Cabaçal VMS Belt’s M&I resources total 1.4Moz Au, 0.6Blbs Cu, 5.6Moz Ag, 217.4Mlbs Zn and 49.9Mlbs Pb; and

Cabaçal DFS metallurgical studies have optimised recoveries of Au, Cu & Ag.

London, United Kingdom--(Newsfile Corp. - January 20, 2026) - Meridian Mining plc (TSX: MNO) (FSE: N2E0) (OTCQX: MRRDF) ("Meridian" or the "Company") is pleased to announce the results of separate Mineral Resource Estimates ("MRE") for the Cabaçal deposit and the Santa Helena Central deposit, concluded by its consultant, GE21 Consultoria Mineral. The Cabaçal Au-Cu-Ag project ("Cabaçal") is at an advanced permitting stage1 and is currently advancing to a Definitive Feasibility Study2 ("DFS"), expected in Q4 2026. The completion of the updated resource is one of the initial workstreams to be completed for the DFS, and the updated resource will be used for further studies in connection with the DFS. The Company has not applied any economic analysis to the updated resource beyond that required to state a resource estimate and does not consider the updated resource to be material to Cabaçal or the Company. It does not supersede the results of the Company's prefeasibility study ("PFS") dated March 31, 2025 and the Mineral Reserve Estimate set out in the PFS is considered to remain current3.

The Company is reporting an updated resource for Cabaçal. Cabaçal's M&I resource is reported at 70.1Mt grading 0.6g/t Au, 0.3% Cu, 1.3g/t Ag for 1.3Moz of Au, 0.5Blbs of Cu and 3.0Moz of Ag.

Meridian is also reporting the maiden open-pittable resource for the Santa Helena Central Au-Cu-Ag-Zn-Pb project ("Santa Helena Central"). Santa Helena Central's M&I resource is reported at 5.3Mt grading 0.6g/t Au, 0.4% Cu, 15.5g/t Ag, 1.9% Zn & 0.4% Pb for 95.8Koz of Au, 50.4Mlbs of Cu, 2.6Moz of Ag, 217.4Mlbs of Zn and 49.9Mlbs of Pb. The Company has not applied any economic analysis to the Santa Helena Central resource beyond that required to state a resource estimate and does not consider the resource to be material.

The Company is also reporting an increase in granted mineral rights across the Cabaçal, Jauru and Araputanga Greenstone Belts to Rio Cabaçal Mineraçao ("RCM"). This follows mineral applications being approved for exploration by the National Mining Agency - "Agência Nacional de Mineração" ("ANM"). The Company's granted exploration portfolio has now more than doubled with these titles. Subject to access agreements and licensing, Meridian will initiate exploration activities across the Jauru and Araputanga Belts during 2026, while continuing to expand multiple exploration programs along the Cabaçal Belt.

In this press release, Cabaçal's MRE is compared to that of March 20254. The September 2025 MRE is based on CIBC Analyst Consensus Commodity prices of November 2025: Au USD 3,103/oz, Ag USD 35.34/oz & Cu USD 4.39 /lb to determine cut-off grades (see Note 14 associated with Table 1) as compared to March 2025's MRE that used CIBC Analyst Consensus Commodity prices of November 2024: Au USD 2,119/oz, Ag USD 26.89/oz, Cu USD 4.16, refer to page 6, in the Company's March 31, 2025 MD&A.

Mr. Gilbert Clark, CEO, comments: "A tremendous start to 2026 with Cabaçal's resource update and Santa Helena Central's maiden resource estimate. This confirms the tremendous potential of the Cabaçal Belt that now hosts over one point three million ounces of gold, more than half a billion pounds of copper and over five million ounces of silver all within open pit depths. Santa Helena Central's resource is solely focused on the central part of an open and prospective system with its stand-alone PL application submitted. We can now look to further near-term growth from additional resource and exploration drilling knowing that we are already well on our way to developing these two resource hubs. The near-term development of a modern and sustainable mining operation in the state of Mato Grosso has been greatly advanced with Meridian's growing Au-Cu-Ag resources, the advancement of the DFS and its expanding exploration programs."

Figure 1: Cabaçal and Santa Helena Central resource locations

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Resource Development Studies - Cabaçal

The mineral resource for Cabaçal (Table 1) was classified and prepared in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Definition Standards for Mineral Resources and Mineral Reserves, adopted by the CIM Council on May 10, 2014, as amended (the "CIM Standards"), and the CIM Estimation of Mineral Resources and Mineral Reserves Best Practice Guidelines, adopted by CIM Council on November 29, 2019, as amended (the "CIM Guidelines") by Mr. Leonardo Moraes Soares, MAIG. Mr. Soares is an independent Qualified Person as such term is defined under NI 43-101. Mineral resource estimates defined within this 2025 MRE for Cabaçal will feed into the pending DFS, on track for filing in Q4 2026.

ClassificationWeathering

Average ValueMaterial Content

MassAuAgCuAuAgCu

Mtg/tg/t%kozkozkt

MeasuredSaprolite0.330.440.690.124.567.220.38

Transition1.830.550.630.2132.6037.253.81

Fresh Rock62.530.571.360.351,138.522,743.29217.43

Total64.690.571.340.341,175.682,787.77221.61

IndicatedSaprolite0.010.300.990.160.140.460.02

Transition0.070.130.590.220.311.370.16

Fresh Rock5.320.491.000.2283.09170.7711.69

Total5.410.480.990.2283.54172.5911.87

TotalSaprolite0.340.430.700.124.707.680.40

Transition1.900.540.630.2132.9138.623.96

Fresh Rock67.850.561.340.341,221.612,914.06229.12

Total70.100.561.310.331,259.222,960.36233.48

Table 1: Cabaçal deposit mineral resource table.

Notes related to the Mineral Resource Estimate ("MRE"):

Measured and Indicated Resource estimate reported inside open pit constraints. Inferred category was not classified inside open pit constraints.

The Mineral Resource Estimates were prepared in accordance with the CIM Standards, and the CIM Guidelines, using geostatistical and/or classical methods, plus economic and mining parameters appropriate to the deposit

Mineral Resources are not Mineral Reserves and are not demonstrably economically recoverable.

Grades reported using dry density.

The effective date of the MRE was December 31, 2025.

The QP responsible for the Mineral Resources is geologist Leonardo Soares (MAIG #5180).

The MRE numbers provided have been rounded to the estimate relative precision. Values cannot be added due to rounding.

The MRE is delimited by Mining tenement areas.

The MRE was estimated using ordinary kriging in 5m x 5m x 2.5m blocks with sub-blocks of 2.5m x 1.25m x 0.625m.

The MRE report table was produced in Leapfrog Edge software.

The MRE was restricted by a pit shell defined using metal prices of USD 3,103/oz Au, USD 35.34/oz Ag, USD2 4.39/lb Cu, Mining cost of USD 9.11/t mined, processing cost of USD 7.82/t processed, metallurgical recovery calculated block by block based on metallurgical tests, G&A costs of USD 2.19/t processed, and USD 2.36/t processed logistics.

Equivalent Gold grade ("AuEq") was calculated with the following general formula: AuEq = (Au_grade * %Au_Recovery) + (1.346*(Cu_grade * %Cu_Recovery)) + (0.013*(Ag _grade * %Ag_Recovery)).

The QP is not aware of political, environmental, or other risks that could materially affect the potential development of the Mineral Resources other than those typical for mining projects at this stage of development.

The resource cut-off grade applied for Measured and Indicated resources was 0.117 g/t AuEq.

The underground mining void model has been used to deplete the resource.

The mineral exploration data was applied to define the 3D geological model and resource estimate. It was compiled into Leapfrog software for the audit and validation of the organization, integrity and security of the data. The database is considered suitable for the purposes of mineral resource estimation.

The Cabaçal deposit mineral resource database consists of 1,290 drillholes, 34 trenches, 83 channels, 25 auger drilling, 15 mixed drilling, 13 percussion drilling and 12 rotary percussion drilling (Meridian + historic drilling), totalling 139,956.78 metres. This database includes 96,900.22 metres of assayed intervals.

All historic data used for the MRE has been validated statistically to show no significant bias, either by twinned drillholes, extensive re-sampling and assaying of historic drill core, statistical comparison of historical data with Meridian drilling, and by field validation of collar locations.

The 3D geological model was prepared by the QP using Leapfrog Geo software, to define and interpolate geological domains.

The nominal sample length of 1 m was selected to be used in sample compositing based on the analysis of composite support for the Cabaçal deposit. The variograms prepared for each domain were used in Ordinary Kriging for Au (g/t), Cu (%) and Ag (g/t) estimates, using Leapfrog Edge software.

The block model for the Cabaçal Project was built using Leapfrog software. The dimensions of the blocks are 5m x 5m x 2.5m blocks with sub-blocks of 2.5m x 1.25m x 0.625m.

Density data was supplied by Meridian inside the drillhole database with selected intervals of 10-15 cm in length for weathered samples and 1 meter for fresh material. A total of 70,976 density test results are present in the database. The QP assumed a fixed value of 2.16 t/m³ by average density on Saprolite and 2.54 t/m³ for the Saprock horizon based on statistical analysis. Density on Fresh Rock Zone was estimated by inverse weighting distance using a minimum of 5 and a maximum of 15 density sample values.

The Ordinary Kriging (OK) estimation method was applied to estimate the Au (ppm), Cu (%) and Ag (ppm) grades for mineralized domains. The estimates were separated for each domain, respecting the composites of each of the mineralized horizons. Grades were estimated considering Soft Boundary domains.

The classification of mineral resources for the Cabaçal deposit was determined by the QP's using the definitions of the Resources established by the CIM. This process involved assessing data quality and quantity, and resource classification was also based on search pass numbers used in grade interpolation.

The Mineral Resource value was quantified inside a resource pit based on the current cost and assumed commodity price, represented for the Reasonable Prospect for Eventual Economic Extraction (RPEEE), considering as effective date December 31, 2025.

Mineral Resources were classified based on the estimation search radius, in conjunction with geological continuity, data spacing, and confidence in the grade estimates. Distances of up to 55 metres were assigned to Measured Mineral Resources, up to 80 metres to Indicated Mineral Resources.

There were no blocks classified as inferred within the open-pit shell.

The resource cut-off grade applied for low- and high-grade domains in Measured and Indicated resources was 0.117 g/t AuEq.

Figure 2 presents the equivalent gold grade within the block model and the RPEEE pit shell, while Figure 3 shows the mineral resource classification.

Figure 2: Gold Equivalent grade within the block model for Cabaçal and the pit optimized for Reasonable Prospects for Eventual Economic Extraction ("RPEEE").

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Figure 3: Mineral Resource Classification for Cabaçal

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Whilst the resource has grown, the Company notes that the Preliminary Licence for the development footprint of Cabaçal is approved for the volumes of material aligned with those established in the PEA5 and PFS. An increase in the volumes of mined material would require amending the Preliminary Licence, thus extending the Cabaçal development timeline. As a result, the Company will continue to base its Cabaçal DFS and initial development plans on the footprint defined by the Preliminary Licence pit and waste dump areas. Future possibilities may include an expansion of the open pit, implementing backfilling within the approved pit footprint, or potential underground exploitation. The Company will continue to assess near-mine exploration opportunities. The down-dip and down-plunge extensions of the Cabaçal mineral system remain lightly drilled. The Company's focus to date has been restricted to a small number of holes at Cabaçal West. It may be that local flexures or structural intersections, or periodicity in the original VMS architecture, create favourable positions for the copper-gold mineralization event, with scope to test for underground targets. The Company has recently drilled a number of holes to the south-east of Cabaçal with results pending and will progressively test for vectors to potential underground resource extension targets.

Geochemical and geophysical programs remain active in the mine corridor and the Company is purchasing drone-based geophysical sensors to add further to our in-house capabilities for better mapping the structure and stratigraphy for exploration targeting, with equipment expected to be delivered over the course of the first quarter.

Resource Development Studies - Santa Helena Central

The maiden mineral resource for Santa Helena Central (Table 2) was classified and prepared in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Definition Standards for Mineral Resources and Mineral Reserves, adopted by the CIM Council on May 10, 2014, as amended (the "CIM Standards"), and the CIM Estimation of Mineral Resources and Mineral Reserves Best Practice Guidelines, adopted by CIM Council on November 29, 2019, as amended (the "CIM Guidelines") by Mr. Leonardo Moraes Soares, MAIG. Mr. Soares is an independent Qualified Person as such term is defined under NI 43-101.

Average ValueMaterial Content

ClassificationWeatheringMass

MtAuAgCuZnPbAuAgCuZnPb

g/tg/t%%%kozkozktktKt

MeasuredSaprolite0.500.6911.070.390.840.4911.02177.651.964.212.45

Saprock0.550.5313.470.571.270.349.38238.453.177.001.87

Fresh_Rock3.700.5817.070.452.200.4569.032 027.8616.5081.1416.75

Total4.750.5916.020.461.950.4489.432,443.9621.6392.3621.07

IndicatedSaprolite0.080.4311.100.210.780.291.0627.600.160.600.23

Saprock0.030.357.270.550.780.240.377.880.180.260.08

Fresh_Rock0.440.3510.670.201.240.294.93149.840.865.401.25

Total0.550.3610.520.221.150.286.36185.321.216.271.56

Meas + IndSaprolite0.580.6511.070.370.830.4612.08205.252.124.812.67

Saprock0.580.5213.120.571.240.339.76246.333.357.271.95

Fresh_Rock4.130.5616.390.422.090.4473.952,177.7017.3786.5518.01

Total5.290.5615.450.431.860.4395.792,629.2822.8498.6322.62

InferredSaprolite0.000.4311.200.191.250.340.061.450.010.050.01

Saprock0.000.206.780.490.660.250.010.320.010.010.00

Fresh_Rock0.030.3111.670.181.500.300.2911.110.050.450.09

Total0.040.3211.410.191.440.300.3612.880.070.510.11

Table 2: Santa Helena Central deposit mineral resource table.

Notes related to the Mineral Resource Estimate:

Measured and Indicated Resource estimate reported inside open pit constraints.

Mineral Resources are not Mineral Reserves and are not demonstrably economically recoverable.

Grades reported using dry density.

The effective date of the MRE was December 31, 2025.

The QP responsible for Mineral Resources is geologist Leonardo Soares (MAIG #5180).

The MRE numbers provided have been rounded to the estimated relative precision. Values cannot be added due to rounding.

The MRE is delimited by Mining tenement areas.

The MRE was estimated using ordinary kriging in 5m x 5m x 2.5m blocks with sub-blocks of 1.25m x 1.25m x 1.25m.

The MRE report table was produced in Leapfrog Geo software.

The Mineral Resource Estimate (MRE) was constrained by an optimized pit shell generated using the following parameters: metal prices of USD3,103/oz gold, USD35.34/oz silver, USD4.39/lb copper, USD1.22/lb zinc, and USD0.92/lb lead; mining costs of USD2.98/t for oxidized ROM and waste material, USD10.44/t for transitional and fresh ROM material, and USD2.98/t for waste; a processing cost of USD7.82/t processed; general and administrative (G&A) costs of USD2.19/t processed; and logistics costs of USD2.36/t processed.

Equivalent Gold grade ("AuEq") was calculated with the following formula: Fresh Rock Gold Equivalent: AuEq(g/t) = (Au_ppm * 57.0%Rec) + (0.970 * Cu_pct * 76.9%Rec) + (0.270 * Zn_pct * 90.6%Rec) + (0.203 * Pb_pct * 78.3%Rec.) + (0.011 * Ag _ppm * 83.7%Rec.).

Transition Zone Gold Equivalent: AuEq(g/t) = (Au_ppm * 83.1%Rec) + (0.970 * Cu_pct * 75.3%Rec) + (0.270 * Zn_pct * 77.4%Rec) + (0.203 * Pb_pct * 51.4%Rec) + (0.011 * Ag _ppm * 80.1%Rec).

Oxide Zone Gold Equivalent: AuEq(g/t) = (Au_ppm * 78.1%Rec.) + (0.011 * Ag _ppm * 62.3%Rec.).

The resource cut-off grade applied for Measured and Indicated resources was 0.125 g/t AuEq.

The underground mining void model has been used to deplete the resource.

The Santa Helena Central deposit's mineral resource database consists of 327 drillholes, 22 trenches, 104 channels and 47 auger drill holes, and 245 grade control holes (Meridian + historic drilling), with 27,533.96 metres (Table 3). This database includes 18,655.35 metres of assayed intervals.

TypeNumberMeterage

Auger47329.89

Channel104188.69

Diamond 32725145.38

Grade Control245770.77

Trench221099.23

Total74527533.96

Table 3: Santa Helena database drill types.

All historic data used for Santa Helena Central's MRE has been validated statistically to show no significant bias, either by twinned drillholes, extensive re-sampling and assaying of historic drill core, statistical comparison of historical data with Meridian's drilling, and by field validation of collar locations, to validate them. A change of support was performed to guarantee the use of historical data including channel, trench, grade control and auger drilling, by comparing values with the original diamond drill hole (DDH) data.

The 3D geological model was prepared by the QP using Leapfrog Geo software, to define and interpolate geological domains.

The nominal sample length of 1 m was selected to be used in sample compositing based on the analysis of composite support for the Santa Helena Central deposit. The variograms prepared for each domain were used in Ordinary Kriging for Au (g/t), Cu (%), Ag (g/t), Zn (%) and Pb (%) estimates, using Leapfrog Edge software.

The block model for Santa Helena Central was built using Leapfrog software. The dimensions of the blocks are 5m x 5m x 2.5m blocks with sub-blocks of 1.25m x 1.25m x 1.25m.

Density data was supplied by Meridian inside the drillhole database with selected intervals of 10-15 cm in length for weathered samples and 1 meter for fresh material. A total of 11,702 density test results are present in the database. The QP assumed a fixed value of 1.70 t/m³ by average density on Saprolite and 2.33 t/m³ for the Saprock horizon based on statistical analysis. Density on Fresh Rock Zone was estimated by inverse weighting distance using a minimum of 5 and a maximum of 15 density sample values.

Meridian Updates Resources for Cabaçal and Santa Helena Central Deposits

Earlier from Meridian Mining Plc