CERTIFICATE OF QUALIFIED PERSON
I, David G. Thomas, P. Geo, am employed as an associate with Mine Technical Services Ltd (MTS), with an office address at 4110 Twin Falls Drive, Reno, NV, 89511.
This certificate applies to the technical report titled “Cisneros Project, Antioquia, Colombia, NI 43-101 Technical Report that has an effective date of 14 August, 2022 (the
“technical report”).
I am a member of the Engineers and Geoscientists of British Columbia (EGBC Licence # 149114). I am also a member of the Australasian Institute of Mining and Metallurgy
(MAusIMM # 225250).
I graduated from Durham University, in the United Kingdom, with a Bachelor of Science degree in Geology in 1993, and I was awarded a Master of Science degree in Mineral
Exploration from Imperial College, University of London, in the United Kingdom in 1995.
I have practiced my profession for over 25 years since graduation. I have been directly involved in the review of exploration programs, geological models, exploration data,
sampling, sample preparation, quality assurance/quality control, databases, and Mineral Resource estimates for a variety of mineral deposits, including mesothermal vein
deposits. I have worked in Brazil, Colombia, Ecuador, Peru, Chile, Mexico, Argentina, USA, Canada, Australia, Greece, Romania, Bulgaria and Serbia.
As a result of my experience and qualifications, I am a Qualified Person as defined in National Instrument 43–101 Standards of Disclosure for Mineral Projects (NI 43–101) for
those sections of the technical report that I am responsible for preparing.
As a result of my experience and qualifications, I am a Qualified Person as defined in National Instrument 43–101 Standards of Disclosure for Mineral Projects (NI 43–101) for
those sections of the technical report that I am responsible for preparing.
I visited the Cisneros Project on May 19, 2022 and from 26 to 27 September, 2022.
I am responsible for Sections 1 to 27 of the technical report.
I am independent of Antioquia Gold Inc. as independence is described by Section 1.5 of NI 43–101.
I have read NI 43–101 and the sections of the technical report for which I am responsible have been prepared in compliance with that Instrument.
As of the effective date of the technical report, to the best of my knowledge, information and belief, the sections of the technical report for which I am responsible contain all
scientific and technical information that is required to be disclosed to make the technical report not misleading.
Dated: 15 December, 2022
“Signed and sealed”
David G. Thomas, P.Geo.
This report was prepared as National Instrument 43-101 Technical Report
for Antioquia Gold Inc. (AGD) by Mine Technical Services (MTS). The
quality of information, conclusions, and estimates contained herein is
consistent with the level of effort involved in MTS’s services, based on i)
information available at the time of preparation, ii) data supplied by outside
sources, and iii) the assumptions, conditions, and qualifications set forth in
this report. This report is intended for use by AGD subject to terms and
conditions of its contract with MTS. Except for the purposed legislated
under Canadian provincial and territorial securities law, any other uses of
this report by any third party is at that party’s sole risk.
1.0 SUMMARY
1.1 Introduction
Mine Technical Services Ltd (MTS) was retained by Antioquia Gold Inc. (AGD) in June 2022 to prepare a technical report (the Report) on the Cisneros Project (the Project),
located in Colombia.
Commercial production was declared by AGD on March 1, 2019, mining the Guaico and Guayabitos deposits. AGD’s decision to mine these deposits was based on a preliminary
economic assessment, and the company does not have current Mineral Reserve estimates.
AGD and its legal counsel requested that the Report focus on the updated Mineral Resource estimate. The reader is referred to AGD’s ongoing public disclosure for
details of the current mine operations, mine production, metallurgical recovery, cost data and financial results.
1.2 Terms of Reference
The Report was prepared to support AGD’s public disclosure of an update to the Cisneros Project mineral resource estimate in the press release titled “Antioquia Gold Cisneros
Mineral Resource Update” dated November 2, 2022.
Mineral Resources are reported in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Definition Standards for Mineral Resources and Mineral
Reserves (May 2014; the 2014 CIM Definition Standards).
Units used in the report are metric units unless otherwise noted. Monetary units are in United States dollars (US$) unless otherwise stated. The Report uses Canadian English.
1.3 Project Setting
The Project area is 55 km northeast of Medellin and 2 km west of Cisneros at approximately 75°08’25” W Longitude and 6°32’35” N Latitude. The Project is in the department of Antioquia, and lies partially within the municipalities of Cisneros, Yolombo, and Santo Domingo on the main road route that leads north from Medellin to the Caribbean coast via the Magdalena River.
The climate is tropical with elevations ranging between 1,200 m and 1,800 m above sea level, the temperature ranges from 20°C to 30°C. There are frequent tropical rain showers
and electrical storms in the area. Mining operations and exploration activities are conducted year-round.
1.4 Mineral Tenure, Surface Rights, Water Rights, Royalties and Agreements
The Cisneros Project area consists of nine concessions with a total area of approximately 17,145.7 ha. The Project is 100% held by Antioquia Gold Colombia Limitada, an AGD
subsidiary.
Surface ownership is held privately by numerous individuals for agricultural use. To date AGD has negotiated access and drill platform locations with individual land owners to
compensate for any disturbance or loss of crops.
State royalties on gold are 4% of the metal value at the plant site (as per Article 16 of Law 141 in 1994) which are independent of national, departmental and municipal taxes. Gross metal value is determined by using 80% of the London Metals Exchange spot prices for gold and silver, so the effective royalty rate is 3.2%.
The owner of the surface rights covering Mining Title 5671 (Guayabito) is paid a 1% royalty on gold production.
In January 2022, AGD completed seven formalization agreements with artisanal mining operations located on the Cantayus mining title (6195) and the La Palma mining title
(6194). AGD have agreements with the artisanal miners to buy mineralized material, payments are made according to the grades and recoveries estimated in the mine
process plant.
1.1 History
The Cisneros Project area has a long history of gold mining and exploration with over a hundred years of small-scale artisanal mining. To date, at least 62 underground
exploration workings have been located in the general Project area, 49 of which are on Antioquia’s concessions.
Antioquia’s predecessor company Am-Ves Resources Inc. (Am-Ves) completed two phases of exploration on the Guayabito concessions in 2007, consisting of a limited due
diligence sampling program and a preliminary exploration program of geological mapping and sampling.
1.2 Geology and Mineralization
The Guaico and Guayabito deposits have some characteristics of Intrusive-related gold deposits and some characteristics of mesothermal vein deposits.
1.2.1 Regional and Project Geology
The Cisneros Project is located in the northern Andean cordillera in Colombia and lies within the Cretaceous-aged Antioquia batholith. The main compositional types within the
Antioquia Batholith are tonalite and granodiorite.
The structural setting is dominated by several west–southwest striking (at Nus) to southwest striking (at Guayabito) shear zones and faults which show rotation and sinistral
shearing events. North-northeast to northeast trending zones of extension and dilation formed between these controlling shear zones and faults.
The North-northeast striking Guaico and Guayabito veins are extensional veins (tension gashes) that developed between the controlling shear zones/faults.
Mineralization at the Cisneros Project is structurally controlled, and gold is associated with shear zones, breccias and quartz–sulphide veins.
1.2.2 Nus Shear Zone
The Nus shear zone is a composite zone made up of thin ductile shear zones and wider zones of brittle fracturing. The zone varies from approximately 10 m to 45 m in horizontal
width and strikes west–southwest with dips ranging between 65° and 80° to the north– northwest. Gold mineralization is known to occur over a strike length of 400 m and over
a distance of 450 m down-dip. The mineralization is open along strike to the west–southwest at depth.
1.2.3 Guaico
The Guaico veins are a series of north–northeast striking, steeply west-dipping extensional (tension gash) veins. The veins have jogs indicating dextral strike slip,
consistent with antithetic Riedel shears, where dilational vein breccias have formed highgrade mineralized shoots with a sub-vertical plunge within the plane of the veins.
Mineralization is associated with quartz–sulphide veining along a strike length of approximately 200 m and over a down-dip distance of 400 m.
1.2.4 Guayabito
The Guayabito mineralized zone comprises a swarm of north–northeast striking, subvertically dipping veins. There is a second set of northeast-striking mineralized structures
and quartz veins. Gold mineralization has been shown along a strike length of 400 m and over a down-dip distance of 570 m
The higher-grade mineralized shoots are similar to those at Guaico, they and have a subvertical plunge within the plane of the veins.
1.3 Exploration
Exploration completed by AGD includes:
- Grids and surveys: the grid system used for sample locations is WGS84 CCC UTM Zone 18N. Contractors prepared a high-resolution, LiDAR survey-based digital
terrain model (DTM) for AGD; - Surface and underground geological mapping: identified mineralized veins and zones of alteration;
- Geochemical sampling: rock chip, stream sediment and grid soil sampling. Identified areas with anomalous gold values and was used to vector into sites for
drill testing; - Geophysical surveying: ground magnetics, IP/resistivity surveys and airborne radar. Identified lineaments and structures associated with the mineralization at Guaico and Guayabito;
- Underground exploration: underground exploration program, development of ramps, drifts (largely along veins), cross-cuts, raises and other underground openings and collection of chip and panel-chip samples. Data from these programs improved the geological model, provided information on the mineralization geometry, grade and geological continuity.
In addition to the main mineralized zones, AGD has identified a number of prospects, including Mina Azul, Los Planes, Bareño, El Papi, La Manuela, Falda de Nus, Cantayus,
and La Palma.
1.4 Drilling
Drilling completed by AGD on the Project totals 257 surface core holes for a total of 55,801.5 m and 875 underground core drill holes for a total of 34,406.9 m.
A number of core sizes have been used, including NQ, HQ, PQ IEW size core (47.6 mm, 63.5 mm, 85 mm or 25.4 mm respectively).
Geological logging was completed by AGD personnel in paper logs to capture lithology, structure, texture, veining, alteration, mineralization and rock quality designation. The drill
core is photographed before and after sampling.
The average core recovery from surface drill holes at Guaico was 90% for all core holes drilled with approximately 15% of core intervals having a core recovery of <70%. The average core recovery from underground drill holes was 97% for all core holes drilled with about 1% of core intervals having a core recovery of <70%.
At Guayabito, the average core recovery from surface drill holes was 91% for all core holes drilled with approximately 13% of core intervals having a core recovery of <70%. At Guayabito, the average core recovery from underground drill holes was 97% for all core holes drilled with about 2% of core intervals having a core recovery of <70%.
The collar coordinates, for all surface and underground drill holes, were surveyed using a Leica Flexline TS06 plus total station.
The deviation of surface drillholes was surveyed by Smart Drilling S.A.S. Downhole surveys were carried out with multi shot Reflex Ez-Trac with Reflex Ez- Com.
The deviations of underground drilling were measured by Logan Drilling Ltd, with a DeviGyro gyroscope.
The surface drill grids were oriented approximately along and across the strike of the mineralized zones. Section lines are irregularly spaced at distances of 10 m to 30 m apart.
The underground drill holes have a highly variable relationship with true thickness depending on the azimuth and dip of the holes in relation to the orientation of the mineralized zones. Drill cubbies are generally spaced 10 m to 15 m apart along the mine drifts.
1.5 Sampling
Surface rock chip sampling was done using hammer and chisel, and most samples were continuous chips averaging 2–3 kg. Grab samples and select chip samples were also
collected.
Soil samples were collected from either the B horizon or C horizon and were typically around 500 g. The samples were field screened with a plastic colander to remove coarse
rock fragments. The -80-mesh fraction was sent for standard fire assay and inductively coupled plasma (ICP) analysis.
AGD collected drill core samples with variable lengths. Drill core samples of longer or shorter length (0.25–2.0 m) could be collected as necessary to terminate the sample on
geological features of interest.
Core was sampled by cutting the core in half with a wet diamond saw blade along the core axis to prepare a ½-core sample. The ½-core sub-sample was then wet-cut along
the core axis to prepare a ¼-core sub-sample for laboratory dispatch. The second half of core and residual ¼ core was retained in core trays, and was selectively used for
density measurements.
Development galleries are sampled on the front, ribs (walls) and backs (ceiling). Sample lengths and sample contacts are selected based on the mineralised structures. Samples
are either channel samples or panel chip samples and are collected with a hammer and chisel or with portable electric hammer.
AGD sent 177 samples to the SGS laboratory in Medellin (SGS Medellin) for specific gravity, bulk density, and moisture determinations. Subsequent specific gravity and bulk
density determinations were completed by the Cisneros mine laboratory using a waxcoated water displacement method.
Until 2011 all drill core samples were prepared at SGS Medellin and pulps were sent to the SGS laboratory in Lima, Peru (SGS Lima) for analysis. The SGS laboratories were
independent of AGD.
In 2011, the decision was made to switch from using the SGS laboratories to Acme Laboratories S.A. (Acme) in an attempt to expedite the delivery of assay results. Acme
was independent of AGD.
The 2016 drilling campaign samples from the Guayabito Sur area and underground channel samples from the Guaico mine were submitted to ALS Minerals in Medellin for
sample preparation and a split of the pulp was then shipped for analysis to the ALS assay laboratory in El Callao, Peru (ALS Peru). The ALS laboratories were independent of AGD,
and held ISO 9001:2008 and ISO/IEC 17025:2005 accreditations for selected analytical techniques.
The samples from the 2017–2019 drilling and underground sampling programs were sent to SGS Medellin for sample preparation and analysis for gold.
From 2019 to present, AGD has used the Cisneros mine laboratory to analyse all rock and geochemical samples. The Cisneros mine laboratory was certified to the
ISO 9001:2015 accreditation by Bureau Veritas. The mine laboratory is not accredited for analytical work.
The sample preparation protocols vary between the different laboratories.
All samples were assayed for gold using a fire assay method followed by atomic absorption spectroscopy or gravimetric finishes. Selected samples were assayed by
screen-metallic fire assay
1.6 Data Verification
The QP reviewed reports on internal and external data verification conducted by third parties. The QP is of the opinion that the data verification programs indicate that the analytical and geological data stored in the Project database are adequate to support the geological interpretations and Mineral Resource estimates prepared by AGD.
Observations made during the QP’s site visit, in conjunction with discussions with AGD’s technical staff, also support the geological interpretations and Mineral Resource
estimates prepared by AGD.
The QP concluded that the geological and analytical data were collected in a manner suitable to be used for Mineral Resource estimation.
1.7 Metallurgical Testwork
The QP considers the metallurgical testwork and interpretations provided by AGD’s consultants (G&T Metallurgical Services Ltd. and Met-Solve), provided by a related
party’s testing laboratories (Consorcio Minero Horizonte SA, Peru) and shown by metallurgical balance from the mine mill support the metallurgical recoveries used in the
cut-off grade estimation of the Mineral Resource estimates.
1.8 Mineral Resource Estimation
The present updated Mineral Resource estimation is based on the drill hole, channel sample and panel-chip sample database, with a cut-off date of July 8, 2022 and thus does
not include subsequent sampling programs that are concurrent with mining in the Guaico and Guayabito mines.
The QP reviewed the panel-chip and channel samples collected up to the effective date of the Mineral Resource estimate, and confirmed that the additional data would not
significantly change the Mineral Resource estimate.
AGD used Hexagon Mineplan software’s implicit modelling module to create wireframes representing the vein systems and the Nus Shear. The modelling was based upon
lithological, mineralogical, structural and alteration characteristics.
AGD created sets of composites with differing nominal lengths using the estimation domain boundaries to break the composites. The composite lengths for the veins were
chosen using histograms of the assay lengths for each vein.
AGD and the QP collaborated in assessing the most effective method to restrict the influence of extremely high-grade underground samples.
AGD created block models for each vein domain consisting of regular blocks (1 m along strike x 1 m across strike x 2 m vertically). Block models were created for the Nus Shear Zone and the Cuerpo Masivo domains with dimensions of 2 m along strike x 2 m across strike x 2 m vertically.
AGD used a combination of ordinary kriging (OK) or inverse distance weighted to the power of three (ID3) grade interpolation methods in a single pass.
The composite selection parameters for grade estimation in each domain (minimum, maximum and maximum number of composites per hole) were adjusted so as to minimize bias. The data used for estimation includes clustered channel and panel-chip samples collected from underground development, the underground data show the presence of higher-grade mineralized shoots with strike lengths averaging 50 m horizontally with rapid changes to grades below the Mineral Resource estimation cut-off grade over distances of a few meters. The rapid changes in grade were better reproduced by reducing the horizontal search ellipse dimension and by reducing the maximum number of samples used for estimation.
Dry bulk density was estimated directly from bulk density measurements by ID3 where data were available. A dry bulk density of 2.75 g/cm3 was applied in un-estimated areas and in veins with no specific gravity measurements.
The QP validated the block models to ensure appropriate honoring of the input data.
The QP classified blocks to the Measured category using multiple levels of mine development generally spaced less than 15 m apart and in areas with grade continuity above the Mineral Resource cut-off grade. Indicated category blocks were classified in areas with multiple levels of mine development spaced more than 15 m apart or with drilling <25 m apart. Inferred mineral resources were classified in areas with a single mine development level and drilling spaced <50 m apart.
The QP assessed the classified blocks for reasonable prospects of eventual economic extraction by applying preliminary economics for potential underground mining methods.
For the purpose, the QP used input process and operating costs, metal prices, metallurgical recovery and underground mining costs.
A minimum mining width of 1 m was implemented by reporting only those blocks above a minimum grade-thickness. AGD removed blocks falling within 30 m of the topographic surface (a crown pillar of 30 m is required by Colombian law) and volumes already mined out (up to August 14, 2022).
The QP created separate block models for the Nus, Guaico and Guayabito areas using the same set of geological models as those used by AGD. The QP compared the mineral resource estimates. The differences between the estimates are less than 10% in all categories and agree closely in terms of contained metal.
1.9 Mineral Resource Statement
Mineral Resources for the Project were classified using the 2014 CIM Definition Standards by application of a cut-off grade that incorporated mining and metallurgical
recovery parameters. Mineral Resources are constrained to blocks with reasonable prospects for eventual economic extraction based on underground mining assumptions,
commodity prices, metallurgical recoveries and operating costs.
The Qualified Person for the estimate is Mr. David Thomas, P.Geo. Mineral Resources are reported in Table 1-1 as insitu, with an effective date of 14 August, 2022. Mineral
Resources are not Mineral Reserves and do not have demonstrated economic viability.
Factors that may affect the Mineral Resource estimates include: metal price and exchange rate assumptions; changes to the assumptions used to generate the gold grade
cut-off grade; changes in local interpretations of mineralization geometry and continuity of mineralized zones; changes to geological and mineralization shapes, and geological
and grade continuity assumptions; density and domain assignments; changes to geotechnical, mining and metallurgical recovery assumptions; change to the input and
design parameter assumptions that pertain to the underground shapes constraining the estimates; and assumptions as to the continued ability to access the site, retain mineral
and surface rights titles, maintain environment and other regulatory permits, and maintain the social license to operate.
1.10 Interpretation and Conclusions
The Mineral Resource estimate is reported using the 2014 CIM Definition Standards.
The QP considers that additional exploration activities are warranted, as the Guaico and Guayabito deposits remain open at depth. There are additional prospects within the
Project area that warrant additional exploration focus.