Mineros Announces Updated Mineral Reserve and Mineral Resource Estimates for the Nechí Alluvial Gold Property, Colombia
Mineros Announces Updated Mineral Reserve and Mineral Resource
Estimates for the Nechí Alluvial Gold Property, Colombia
HIGHLIGHTS:
Total Proven and Probable Mineral Reserves: 524 million cubic meters (Mm 3)
averaging 80 milligrams per cubic metre (mg/m3 Au), containing 1,355 thousand
ounces (koz) of gold.
Life of Mine (LOM) Plan: Based on Proven and Probable Mineral Reserves, the
LOM plan extends over 12 years, from 2025 to 2036, incorporating pit optimization,
mine scheduling, and modifying factors applied to the Mineral Resources.
Measured and Indicated Mineral Resources: 527 Mm3 averaging 56 mg/m3 Au,
containing 1,005 koz of gold.
Inferred Mineral Resources: 223 Mm3 averaging 62 mg/m3 Au, containing 447 koz
of gold Mineral Resources are exclusive of the Mineral Reserves.
Enhanced Geological Modeling: The updated estimates reflect the transition from a
2D polygonal method to a 3D block model, improving the accuracy of geological
modeling and mine planning.
Drilling Program: From 2021 to November 25, 2024, Mineros completed 1,864 drill
holes, totaling 46,375.5 metres (m). The drilling program provided a refined
understanding of the deposit’s gold distribution.
MEDELLÍN, Colombia--(BUSINESS WIRE)--February 28, 2025--Mineros S.A. (TSX:MSA,
MINEROS:CB) (“Mineros” or the “Company”) is pleased to announce updated Mineral
Resource and Mineral Reserve ("MRMR") estimates for the Company’s Nechí Alluvial Gold
Property, located in the Antioquia Department, Colombia (the “Nechí Alluvial Property”).
These estimates, with an effective date of December 31, 2024, were prepared in accordance with
National Instrument 43-101 ("NI 43-101") and will be supported by a technical report that
Mineros will file on SEDAR+ at www.sedarplus.ca within 45 days of this announcement.
Mineros’ 100% owned Nechí Alluvial Property is located approximately 190 km north-northeast
of Medellín in the northeast of the Antioquia Department, covering the municipalities of El
Bagre, Zaragoza, Caucasia, and Nechí.
The Nechí Alluvial Property hosts classic alluvial gold deposits, which have been commercially
exploited for gold by dredging since 1937. Historical gold production from the Nechí alluvial
deposits from 1895 to 2024 is approximately 9.1 Moz Au, of which Mineros’ operations account
for approximately 3.2 Moz Au.
The alluvial deposits extend for more than 50 km along the Nechí River, with widths up to 3.5
km. The current active area of alluvial operations extends approximately 12.5 km on the east side
of the Nechí River towards the northern part of the property.
The updated MRMR reflects recent exploration success, resource modeling enhancements, and
economic evaluations.
Andres Restrepo, President and Chief Executive Officer said, “We are pleased to announce this
updated Mineral Reserve and Mineral Resource estimate to the market. We are confident that it
will improve our investors’ understanding of the Nechí Alluvial Property, demonstrate the value
of the asset, and enable us to optimize our extraction of the gold contained therein.”
Mineral Reserves
Proven and Probable Mineral Reserves were estimated by identifying the economically mineable
part of the Measured and Indicated Resources. Mineral Reserves were not reported based on a
specific cut-off grade but rather are based on Mineral Resource material within the mineralized
zone that shows a positive net value after deducting associated operating costs. For material to
qualify as Mineral Reserves, its estimated value must cover all associated operating costs.
The effective date for the Mineral Reserves at the Nechí Alluvial Property is December 31, 2024
(Table 1). These reserves are estimated within the designed pits depleted by the mined-out areas
as of December 31, 2024, using a gold price of US$1,750 per ounce (exchange rate of
COP$4,000.00 = US$1.00). Due to the mining method employed and the nature of the
mineralization, the Mineral Reserves at the Nechí Alluvial Property are reported in millions of
cubic metres (Mm³) for the volume of mineralized and overlying barren material, milligrams per
cubic metre (mg/m³) for gold grade, and troy ounces for contained gold. Alluvial gold at Nechí is
assumed to be 89% fine for reserve estimation.
Table 1: Nechí Mineral Reserve Statement (effective December 31, 2024)
Category Volume
(Mm3)
Gold Grade
(mg/m3)
Contained Gold
(koz Au)
Proven
Bucket Line Dredges 74 72 171
Llanuras Production Unit 9 51 15
Brazilian Dredges 3 81 8
Total Proven 86 71 195
Probable
Bucket Line Dredges 335 84 901
Llanuras Production Unit 30 55 53
Brazilian Dredges 73 87 206
Total Probable 438 82 1,159
Total Proven and Probable 524 81 1,355
Notes:
1. CIM (2014) definitions were followed for Mineral Reserves.
2. Mineral Reserves are estimated using an average long-term gold price of US$1,750 per ounce.
3. An exchange rate of COP$4,000.00 = US$1.00 was used.
4. The total volume includes both the diluted mineralized material and overburden material.
5. Gold grade is diluted to total volume which includes both mineralization and overburden.
6. The fineness of gold in the doré is 89%. The gold grade and the contained gold are adjusted for fineness.
7. Average metallurgical process recovery varies by equipment type, from 83% for the bucket line dredge,
currently 58% for the Llanuras (suction dredge), and an average of 61% for the different Brazilian
dredges.
8. Recovery rates are based on the reconciliation factor or the percent of gold recovered versus the estimated
amount of gold.
9. Mining dilution of 10% at zero grade is applied to the in- situ volume, affecting both the mineralization and
the overburden.
10. Mining extraction is 100%.
11. Mined out blocks were assigned a zero recovery to eliminate their potential for revenue generation. Mined
out areas were updated as of December 31, 2024.
12. Mineral Reserves are estimated to the maximum alluvial mining depth of 12 m for suction dredge and 30
m for bucket line dredge.
13. A minimum mining width of 90 m was used.
14. Overall pit slopes are 37°.
15. Mineral Reserves are reported on a 100% ownership basis.
16. Numbers may not add due to rounding.
Mining Methods and Life of Mine Production Schedule
The alluvial mining operations at the Nechí Alluvial Property involve the removal of overburden
and the excavation of gold-bearing gravels using large floating dredges. The overall mining
process consists of the following four phases:
Overburden removal with suction dredges or “Brazilian” suction dredges.
Gravel removal with dredges.
Size classification and gravimetric gold extraction.
Final metallurgical processing of doré at the metallurgical plant and laboratory at
Mineros’ El Bagre complex.
There are three primary mining methods currently used at the Nechí Alluvial Property:
Alluvial plain mining – The predominant method, which utilizes a combination of suction
dredges for overburden removal and bucket line dredges for mining and processing gold-
bearing gravels.
Suction plain mining – Performed using “Brazilian” suction dredges, which incorporate
onboard processing plants.
Llanuras mining – Uses a combination of suction dredges for overburden removal and the
Llanuras production unit, which consists of a modified suction dredge for mining gold-
bearing gravels, and a floating plant known as the Llanuras Plant.
Mineros has prepared a LOM plan based on Proven and Probable Mineral Reserves, extending
over approximately 12 years from 2025 to 2036 (Figure 1). The LOM plan includes pit
optimization, pit design, mine scheduling, and the application of modifying factors to the
Measured and Indicated Mineral Resources.
Total dredging production averages 43.6 Mm3 from 2025 to 2032 with the peak mining rate of
53.7 Mm3 in 2027. Diluted gold grade peaks in 2036 at 111 mg/m3. Over the life of mine, bucket
line dredging accounts for approximately 78% of total production (overburden and
mineralization).
Geology and Mineral Resources
Gold mineralization is hosted within stratified sedimentary sequences of the Nechí River valley,
primarily within coarse gravel units interbedded with lenses of silt, sand, and clay. The
distribution of gold is strongly correlated with granulometry, with coarse gravel units typically
exhibiting higher gold concentrations. Ancient paleochannel systems of the Nechí River have
been identified as key gold-bearing structures, providing continuity for resource modeling and
estimation. The unique geological setting and predictable mineralization styles of the Nechí
deposit support its potential for long-term alluvial gold production.
Mineros has completed a Mineral Resource estimate for the Nechí Alluvial Property
incorporating 12,490 drill holes totaling 290,673.2 m. This estimate marks the transition from
conventional 2D polygonal estimation to a 3D block modeling approach, significantly enhancing
the spatial accuracy, geological continuity, classification of resources, optimized mine planning,
and better operational decision-making.
The use of Leapfrog 3D modeling software has enabled the delineation of geological domains
and the distinction between production zones, overburden, and bedrock, aligning resource
estimation practices with industry best standards.
Mineral Resource and Mineral Reserve Reporting:
Gold grade is naturally diluted by barren overburden, which is assigned a gold grade of
zero.
For estimation, the contained gold is assumed to be 89% fine, ensuring an accurate
representation of recoverable gold content.
The gold grade in the Mineral Resource and Mineral Reserve estimates is derived by
multiplying total gold grade by the 0.89 fineness factor, with contained gold values
adjusted accordingly.
The Mineral Resources were estimated using the drill hole results available to November 25,
2024. As of December 31, 2024, the Mineral Resource estimate comprises a total Measured and
Indicated volume of 527 Mm³ grading 56 mg/m³ Au, containing approximately 1,005 koz of
gold. In addition, Inferred Resources total 223 Mm³ grading 62 mg/m³ Au, for 447 koz of gold.
The updated resource model is reported within an ultimate pit shell generated at a Revenue
Factor of 1.0 using an average, long-term gold price of US$1,900/oz and an exchange rate of
COP$4,000.00 = US$1.00, and includes low-grade blocks situated within the pit shell. The
estimate is exclusive of Mineral Reserves and depleted by the mined-out areas as of December
31, 2024.
Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Definition Standards for Mineral
Resources and Mineral Reserves dated May 10, 2014 (CIM (2014) definitions) were used for
Mineral Resource classification. A summary of the Mineral Resources at the Nechí Alluvial
Property is shown in Table 2.
Table 2. Nechí Mineral Resource Statement (effective December 31, 2024).
Category Volume
(Mm3)
Gold Grade
(mg/m3 Au)
Contained Gold
(koz Au)
Measured 79 55 140
Indicated 448 56 865
Total Measured and Indicated 527 56 1,005
Inferred 223 62 447
Notes:
1. CIM (2014) definitions were followed for Mineral Resources.
2. Mineral Resources are reported within an ultimate pit shell generated at Revenue Factor of 1.0 using an
average, long-term gold price of US$1,900/oz Au and an exchange rate of COP4,000.00:US$1.00, and
include low-grade blocks situated within the pit.
3. Gold grade is diluted to total volume, which includes both mineralization and overburden.
4. The fineness of gold in the doré is 89%. The gold grade and the contained gold are adjusted for fineness.
5. Average thickness of the resource pay gravel is 30 m. Average thickness of overburden is 15.0 m.
6. Mineral Resources are depleted by mined-out areas updated as of December 31, 2024.
7. Mineral Resources are exclusive of Mineral Reserves.
8. Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability.
9. Numbers may not add due to rounding.
NEXT STEPS
Exploration Drilling: A 10,000 m drill program is planned for 2025, targeting expansion
of the current Mineral Resources, conversion from Mineral Resources to Mineral
Reserves, and infill drilling in the current production areas.
Mine and Processing Optimization Studies: Further evaluation of operational
efficiencies and cost-reduction strategies.
ABOUT MINEROS S.A.
Mineros is a Latin American gold mining company headquartered in Medellin, Colombia. The
Company has a diversified asset base, with mines in Colombia and Nicaragua, and a pipeline of
development and exploration projects.
The board of directors and management of Mineros have extensive experience in mining,
corporate development, finance, and sustainability. Mineros has a long track record of
maximizing shareholder value and delivering solid annual dividends. For almost 50 years
Mineros has operated with a focus on safety and sustainability at all its operations.
Mineros’ common shares are listed on the Toronto Stock Exchange under the symbol “MSA”,
and on the Colombia Stock Exchange under the symbol “MINEROS”.
QUALIFIED PERSON
Luis Fernando Ferreira de Oliveira, MAusIMM CP (Geo), Mineral Resources and Reserves
Manager for Mineros, and Dorota El-Rassi, M.Sc., P.Eng., Manager M&A for Mineros, both
qualified persons within the meaning of NI 43-101 supervised the preparation of the information
that forms the basis for this news release. Mr. Ferreira and Ms. El-Rassi have verified the
scientific and technical information in this release, including sampling, analytical and test data
underlying the updated Mineral Resource estimate, and the opinions expressed herein.
The verification process included a review of drilling, sampling, and analytical data. The
qualified persons determined that such data had been collected in accordance with industry best
practices and validated through independent reviews. There were no limitations on the
verification process.
The MRMR estimate and technical information pertaining to it contained in this news release
were reviewed and approved by Luke Evans, M.Sc., P.Eng. Principal Geologist , SLR
Consulting (Canada) Ltd. (SLR) and Eduardo Zamanillo, M.Sc., MBA, ChMC(RM), Principal
Mining Engineer, SLR. Messrs. Evans and Zamanillo are independent qualified persons within
the meaning of NI 43-101.
FORWARD-LOOKING STATEMENTS
This news release contains “forward looking information” within the meaning of applicable
Canadian securities laws. Forward looking information includes statements that use forward
looking terminology such as “may”, “could”, “would”, “will”, “should”, “intend”, “target”,
“plan”, “expect”, “budget”, “estimate”, “forecast”, “schedule”, “anticipate”, “believe”,
“continue”, “potential”, “view” or the negative or grammatical variation thereof or other
variations thereof or comparable terminology. Such forward looking information includes,
without limitation, statements with respect to Mineral Reserves and Mineral Resources estimates
of Nechí Alluvial Property.
Forward-looking information is based upon estimates and assumptions of management in light of
management’s experience and perception of trends, current conditions and expected
developments, as well as other factors that management believes to be relevant and reasonable in
the circumstances, as of the date of this news release including, without limitation, assumptions
about: exploration development, and production from the Nechí Alluvial Property; future prices
of gold and other metal prices; the timing and results of exploration and drilling programs, and
technical and economic studies; completion of its drilling programs; the accuracy of any Mineral
Reserve and Mineral Resource estimates; the geology of the Nechí Alluvial Property being as
described in the applicable technical reports; production costs; the accuracy of budgeted
exploration and development costs and expenditures; the price of other commodities such as
fuel; future currency exchange rates and interest rates; operating conditions being favourable
such that the Company is able to operate in a safe, efficient and effective manner; political and
regulatory stability; the receipt of governmental, regulatory and third party approvals, licenses
and permits on favourable terms; obtaining required renewals for existing approvals, licenses and
permits on favourable terms; requirements under applicable laws; sustained labour stability;
stability in financial and capital goods markets; inflation rates; availability of labour and
equipment; positive relations with local groups, and the Company’s ability to meet its obligations
under its agreements with such groups; and satisfying the terms and conditions of the Company’s
current loan arrangements. While the Company considers these assumptions to be reasonable, the
assumptions are inherently subject to significant business, social, economic, political, regulatory,
competitive and other risks and uncertainties, contingencies and other factors that could cause
actual actions, events, conditions, results, performance or achievements to be materially different
from those projected in the forward-looking information. Many assumptions are based on factors
and events that are not within the control of the Company and there is no assurance they will
prove to be correct. For further information of these and other risk factors, please see the “Risk
Factors” section of the Company’s annual information form dated March 25, 2024, available on
SEDAR+ at www.sedarplus.ca.
The Company cautions that the foregoing lists of important assumptions and factors are not
exhaustive. Other events or circumstances could cause actual results to differ materially from
those estimated or projected and expressed in, or implied by, the forward-looking information
contained herein. There can be no assurance that forward-looking information will prove to be
accurate, as actual results and future events could differ materially from those anticipated in such
information. Accordingly, readers should not place undue reliance on forward-looking
information.
Forward looking information contained herein is made as of the date of this news release and the
Company disclaims any obligation to update or revise any forward-looking information, whether
as a result of new information, future events or results or otherwise, except as and to the extent
required by applicable securities laws.
Contacts
For further information, please contact:
Ann Wilkinson
VP of Investor Relations
+1 (647) 496-3011
Juan Obando
Investor Relations Manager
(+57) 574 266 5757
John Boidman
Renmark Financial Communications Inc.
+1 (514) 939-3989 or +1 (212) 812-7680