MNO.TO · 2026-09-10 12:00:00

Meridian Mining's Definitive Feasibility Study for Cabaçal Delivers After-Tax NPV5 of USD 2.09 Billion, 108% IRR, and 0.9 Year Payback Cabaçal DFS's Highlights

Economic Studies

Meridian Mining's Definitive Feasibility Study

for Cabaçal Delivers After-Tax NPV5 of USD

2.09 Billion, 108% IRR, and 0.9 Year Payback

Cabaçal DFS's Highlights:

(

All amounts are in United States Dollars unless otherwise stated

)

Meridian reports economics from Cabaçal's Definitive Feasibility Study;

Cabaçal DFS After-Tax

outputs

Base Case Economics

$3,570 Au / $5.03 Cu / $50.17 Ag

Spot Price Economics

$4,394 Au / $6.53 Cu / $64.14 Ag

Net Present Value @ 5%

USD 2.092 Billion

USD 2.902 Billion

Internal Rate of Return

107.6.%

134.7%

Payback Period

0.9 Year

0.7 Year

NPV

/Capex

6.5x

9.0x

*Spot metal prices dated on London close, 10 September 2026

Base Case Total LOM Revenue USD 5.4 billion and LOM After-Tax Free Cash flow of USD 2.9

billion;

Life of Mine All-In-Sustaining-Costs ("AISC") of USD 1,056/oz AuEq

;

First production years 1-5:

Average annual production of 183,526 AuEq;

AISC of USD 715/oz AuEq;

Average annual after-tax free cashflow of USD 413.8 million;

Initial Capital Expenditure of USD 322M includes 10% contingency, tax credits and pre-investment

for expansion to 4.5mtpa from year 4 onwards;

Offsite civil works for mine commenced:

Installation Licence for power line construction granted.

See Technical Note for AuEq equation.

London, United Kingdom--(Newsfile Corp. - September 22, 2026) - Meridian Mining plc (LSE: MNO)

(TSX: MNO) (FSE: N2E0) (Tradegate: N2E0) (OTCQX: MRRDF) ("Meridian" or the "Company") is

pleased to announce the results of the Definitive Feasibility Study (the "DFS" or the "Study") for the

Cabaçal gold-copper-silver deposit in Mato Grosso, Brazil ("Cabaçal" or the "Project").

Meridian will host a Live Webcast to discuss the Cabaçal DFS Results on September 22

2026 at 3:00pm UK, 10:00 am EST. A presentation by management will be followed by Q&A.

Conference Call Webcast details:

Webcast URL:

https://www.investormeetcompany.com/meridian-mining-plc/register-investor

Mr. Gilbert Clark, CEO, comments: "What a tremendous result has been achieved. The DFS delivered a

NPV

exceeding two billion dollars, an IRR over one hundred percent and a payback of less than one

year. Our NPV

to Capex ratio of 6.5 times is a testament to the compelling economic potential of the

Cabaçal project. Using spot prices these all get better again. Reading these numbers, it elevates

Cabaçal to potentially be the next "near-term" VMS gold-copper mine developed globally. Importantly,

the study is based on a conservatively engineered mine design, that can be financed and built.

Congratulations to the team for delivering a tremendous result.

I want to thank all our shareholders and stakeholders, without your support, we could not have delivered

these remarkable results that unlock tremendous value.

Meridian is already well on the path to building Cabaçal. Preconstruction investments are underway on

multiple fronts with committed capital contracts of USD 15.9 million. Installation licence permitting has

been lodged, and financing activities to construct Cabaçal are progressing. Developing the next near-

term VMS Au-Cu-Ag mine of South America is a tremendous opportunity. Combine this with a highly

prospective exploration portfolio and you have an incredibly compelling mining investment opportunity."

Summary of Cabaçal Definitive Feasibility Study Results

The DFS for Cabaçal was completed by Ausenco do Brasil Engenharia Ltda and Ausenco Engineering

Canada ULC (together "Ausenco"), supported by GE21 Consultoria Mineral Ltd ("GE21"). The Study

findings show that Cabaçal has industry-leading economics for a conventional open-pit mine, mill, and

process plant. Cabaçal's ore produces a clean, high-grade Cu + Au-Ag concentrate that easily convert

to high-grade blister copper in standard flash furnaces. The DFS supersedes Cabaçal's March 2025

Preliminary Feasibility Study ("PFS")

. Key updates reported in the Study include stronger economics,

an updated and larger Mineral Reserve statement, an optimised mine plan, and improved metallurgy.

Table 1: Summary of Cabaçal DFS's NPV

sensitivities to gold and copper prices (silver at Base

Case)

To view an enhanced version of this graphic, please visit:

https://images.newsfilecorp.com/files/7354/315328_37c5e3dcd40e6b43_001full.jpg

Table 2: Summary of Cabaçal DFS's IRR sensitivities to gold and copper prices (silver at Base

Case)

To view an enhanced version of this graphic, please visit:

https://images.newsfilecorp.com/files/7354/315328_37c5e3dcd40e6b43_002full.jpg

Item

LOM

Plant Feed Mined

56.0

Waste Mined

79.3

Total Mined

135.4

Strip Ratio

Waste:Mineralised Ore

1.4

Milled tonnes

56.0

Mill Throughput

Mt/annum

2.5 to 4.5 (year 4 on)

Item*

LOM

Total gold production

ounces

983,537

Total copper production

tonnes

180,634

Total silver production

ounces

1,779,720

Average metallurgical recovery - Gold

89.3%

Average metallurgical recovery - Copper

92.8%

Average metallurgical recovery - Silver

74.3%

Item

LOM

Average annual gold production (AuEq)

000 Ounces

112.9

Recovered Gold (AuEq)

000 Ounces

1,569.6

Total Cash Cost

USD/oz AuEq

982.9

Sustaining capital

USD/oz AuEq

49.3

All in Sustaining Costs ("AISC")

USD/oz AuEq

1,056.0

Table 3: DFS production summary. * The production numbers may differ from reserves estimates

when using average metallurgical recovery due to different calculation methodologies.

Item

Base Case

Spot Case

Life of mine

Years

13.9

NPV

USD million

2,092

2,902

IRR

108%

135%

Payback

Year

0.9

0.7

Initial Capital Expenditure*

USD million

322

Expansion Capital Expenditure*

USD million

Sustaining Capital Expenditure

USD million

*Net of Tax credits

Item

Average Year 1-

Total LOM

Average Year 1-

Total

LOM

Revenue

USD million

629

5,358

787

6,727

Operating Costs

USD million

1,256

Free cash (After Tax)

USD million

414

2,867

542

3,975

Table 4: Project economics at base case and spot case

Item

Base Case

Spot Case

Gold Price

USD/oz

3,570

4,394

Copper Price

USD/lb

5.03

6.53

Silver Price

USD/oz

50.17

64.14

Exchange Rate

BRL:USD

5.40

Corporate Tax Rate

25.0%

Social Tax

9.0%

SUDAM Tax Reduction

75.0%

SUDAM Tax Reduction

Years

Gold Royalty Rate

1.5%

Copper Royalty Rate

2.0%

Silver Royalty Rate

2.0%

Table 5: Cabaçal DFS model inputs

Figure 1: Cabaçal project annual and cumulative Base Case cash flow

To view an enhanced version of this graphic, please visit:

https://images.newsfilecorp.com/files/7354/315328_37c5e3dcd40e6b43_003full.jpg

Cabaçal Capital Costs

Initial Costs

USD million

Mine

Process

156

Piles

Offsite Infrastructure

Indirect Costs (including Owner costs)

Contingency

Tax Credit

(21)

Total Initial Capital

322

Expansion Capital

Sustaining Capital

Mine Closure Costs

Salvage Value

(23)

Table 6: DFS capital cost breakdown

Cabaçal Operating Costs Breakdown

Item

USD/t milled

USD/oz AuEq

Mining Costs

9.93

370.76

Labour

1.48

55.12

Power

2.69

100.29

Reagents & Consumables

4.06

151.77

Maintenance

1.05

39.19

Water/sewage

0.11

4.23

Road maintenance

0.10

3.71

Laboratory

0.35

13.11

Concentrate Logistics

2.20

82.08

Tax Credit

(1.88)

(70.04)

G&A

2.32

86.56

Total Operating Costs

22.41

836.79

Table 7: DFS operating cost breakdown

Study Contributors

The DFS team was led by Ausenco, a global provider of consulting and engineering services for mining

projects. Ausenco were supported by GE21 Consultoria Mineral Ltda (resource and reserve estimation,

mine plan and schedule), SGS Lakefield Canada (metallurgy) and Flowsheets Metallurgical Consulting

Inc (metallurgy and mineral processing).

Resource Development Studies

The mineral resource for Cabaçal (Table 8) 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 the 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. The mineral resource was previously announced by Meridian on January 20,

2026, and is unchanged.

Classification

Weathering

Average Value

Material Content

Mass

g/t

koz

Measured

Saprolite

0.33

0.44

0.69

0.12

4.56

7.22

0.38

Transition

1.83

0.55

0.63

0.21

32.60

37.25

3.81

Fresh Rock

62.53

0.57

1.36

0.35

1,138.52

2,743.29

217.43

Total

64.69

0.57

1.34

0.34

1,175.68

2,787.77

221.61

Indicated

Saprolite

0.01

0.30

0.99

0.16

0.14

0.46

0.02

Transition

0.07

0.13

0.59

0.22

0.31

1.37

0.16

Fresh Rock

5.32

0.49

1.00

0.22

83.09

170.77

11.69

Total

5.41

0.48

0.99

0.22

83.54

172.59

11.87

Total

Saprolite

0.34

0.43

0.70

0.12

4.70

7.68

0.40

Transition

1.90

0.54

0.63

0.21

32.91

38.62

3.96

Fresh Rock

67.85

0.56

1.34

0.34

1,221.61

2,914.06

229.12

Total

70.10

0.56

1.31

0.33

1,259.22

2,960.36

233.48

Table 8: 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 are 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's 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, USD 4.39/lb Cu, mining cost of USD

2.95/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) + (0.970*

(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 organisation, 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 drillholes, 15 mixed drillholes, 13 percussion drillholes and 12 rotary percussion drillholes

(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, by twinned

drillholes, extensive re-sampling and assaying of historic drill core, statistical comparison of historical

data with Meridian drilling, and 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 blocks have dimensions

of 5m x 5m x 2.5m, 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 metre for fresh material. A total of 70,976 density test results is

present in the database. The QP assumed a fixed value of 2.16 t/m³ for average density on Saprolite

and 2.54 t/m³ for the Saprock horizon, based on statistical analysis. Density in the fresh-rock zone was

estimated by inverse-distance weighting, 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 (g/t), Cu (%) and Ag (g/t)

grades for mineralised domains. The estimates were separated for each domain, respecting the

composites of each of the mineralised horizons. Grades were estimated considering Soft Boundary

domains.

The classification of mineral resources for the Cabaçal deposit was determined by the QPs 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),

with an effective date of 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, and 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 optimised for

Reasonable Prospects for Eventual Economic Extraction ("RPEEE").

To view an enhanced version of this graphic, please visit:

https://images.newsfilecorp.com/files/7354/315328_37c5e3dcd40e6b43_004full.jpg

Figure 3: Mineral Resource Classification for Cabaçal

To view an enhanced version of this graphic, please visit:

https://images.newsfilecorp.com/files/7354/315328_37c5e3dcd40e6b43_005full.jpg

Whilst the DFS resource has increased from that issued for the PFS, 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 PEA

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 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. It may be that local flexures or

structural intersections, or periodicity in the original VMS architecture, create favourable positions for the

copper-gold mineralisation event, with scope to test for underground targets. The Company will

progressively test for vectors to potential underground resource extension targets.

Geochemical and geophysical programmes remain active in the mine corridor and the Company has

purchased drone-based geophysical sensors to add further to our in-house capabilities for better

mapping the structure and stratigraphy for exploration targeting.

Technical Notes

The CIBC Analyst Consensus Commodity prices of November 2025 have been used for the Mineral

Resource Estimates: Gold USD 3,103/oz, Silver USD 35.34/oz, Copper USD 4.39/lb, Zinc USD 1.22/lb,

and Lead USD 0.92/lb. Metallurgical recoveries have been based on test work programmes undertaken

on drill core at SGS Lakefield in Canada, determining the following parameters:

Cabaçal Fresh Rock Gold Recovery:

Recovery for grades less than 0.5g/t Au = 5.4022

∗

Ln(Grade)

+88.66

Recovery for grades equal to or higher than 0.5g/t Au = 5.807

∗

(Grade)

+85.11

Recovery for grades higher than 1.65g/t Au is capped at 94.69%

Cabaçal Fresh Rock Copper Recovery:

Recovery for grades less than 0.5% Cu = 3.9067

∗

Ln(Grade)

+95.269

Recovery for grades equal to or higher than 0.5% Cu = 1.3393

∗

Ln(Grade)

+97.83

Recovery for grades higher than 1.03% Cu is capped at 98.1%

Cabaçal Fresh Rock Silver Recovery:

Recovery for grades less than 0.5g/t Ag = 30.354

∗

Ln(Grade)

+43.691

Recovery for grades equal to or higher than 0.5g/t Ag = 3.8821

∗

(Grade)

+67.406

Recovery for grades higher than 5.0g/t Ag is capped at 86.81%

Cabaçal (Saprock) Transition Zone:

For all blocks that contain more than 0.1% sulphur, the fresh rock recovery formula would apply

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