Project Overview

Cisneros is 80 km northeast from Medellin, some two hours by paved road and close to infrastructure including high voltage power lines. The property hosts a structurally controlled mesothermal lode gold system. Drilling began in October 2009 and to date the company has drilled over 45,000 metres as it worked to produce an initial mineral resource estimate in August 2013 and updated mineral resource estimate and Preliminary Economic Assessement in 2018 that focused on the Guayabito and Guaico deposits.

For additional details on the Updated Mineral Resource and Preliminary Economic Assessment please refer to the news release of 20th February, 2018



The Cisneros project is located within the late Cretaceous (approx. 88.0 Ma) Antioquia Batholith, a significant intrusive body within the Central Cordillera belt of Colombia. It is structurally deformed, granodioritic-tonalitic rocks and gold mineralization typically occurs within sulphide-rich (pyrite, chalcopyrite) quartz veins and breccias that are controlled by significant primary and secondary regional faulting occurring on the property. The Cisneros area has an history of artisanal gold production and over 60 artisanal gold mines have been identified on the property.

Antioquia Gold has been exploring the Cisneros project since 2007 and has made nine individual, separate gold discoveries; two of which, the Guayabito and Guaico deposits, will now be taken into production.

The Guayabito deposit is a multi-zone, en-echelon style deposit with individual zones achieving strike lengths of 180m, depths of 300m and localized true thickness up to 5.0m. Significant drill intercepts include 4.0m @ 14.7 g/t Au in hole GYB11-052 and 5.1m @ 9.3 g/t Au in hole PC10-026.

The Guaico deposit is similar to Guayabito as it is a multi-zone, en-echelon style deposit in which zones identified to date have strike lengths up to 200m, have been identified to a sub-surface depth of 300m and localized true thickness within individual zones is up to 3.0m. Significant drill intercepts include 6.9m @ 15.6 g/t Au in hole PC09-020; 3.5m @ 19.6 g/t Au in hole GCO11-009 and 2.0m @ 34.1 g/t Au in hole GCO11-007.

Drilling results include 4.4m @ 16.6 g/t Au on the Guaico structure, 11.2m @ 5.4 g/t Au on the Nus structure and 37.2m @ 4.5 g/t Au on the Guayabito structure. The Guaico structure has been identified along 200m strike length and 200m vertical depth below the Guaico artisanal mine and is open at depth and to north, with intercepts up to 2.3m @ 22.72 g/t Au. The Nus structure has been identified along 950m strike length and 100m vertical depth and is open at depth and along strike to the east and west. This structure exhibits the presence of silver and copper along with gold.

Preliminary Economic Assessment and Mineral Resource

In February 2018, Antioquia Gold published a NI 43-101 compliant Preliminary Economic Assessment and updated mineral resource estimate for Cisneros prepared by Fernando Linares, MAusIMM of Lima, Peru.

The Report has an effective date of September 24, 2017 and the Corporation has filed the complete report on SEDAR.

PEA Highlights

Mineral Resource Estimate

The updated resource estimate incorporates results from 110 drill holes, including results of 14 new drill holes drilled in 2016-2017 and 1130 channels sampled during 2016 and 2017. The mineralized structures, updated with new data are: Nus, Guaico, Footwall-03, Footwall-05, Vega and La Manuela-01. Resources for Guayabito North and Papi, remain unaltered from the 2013 mineral resource estimate.

Updated mineral resources for the Cisneros Properties, above cut-off grade, for all mineralized structures consist of 760,731 tonnes of measured and indicated resources with an average grade of 5.233 g/t Au and 536,211 t of Inferred Mineral Resources with an average grade of 6.345 g/t Au.

Total Measured Resource Estimates for Cisneros Deposits

Deposit Name Code Tonnage Au g/t Au oz
Nus NUS 200,877 3.548 22,916
Guaico GCO 26,464 7.529 6,406
Footwall-05 GCFW5 13,596 9.759 4,266
Footwall-03 GCFW3 11,919 7.561 2,898
La Manuela-01 MNL_1 1,133 5.237 191
Guayabito GBY 46,370 7.700 11,479
Papi PAPI 3,592 6.966 804
Total Measured 303,951 5.010 48,959

Total Indicated Resource Estimates for Cisneros Deposits

Deposit Name Code Tonnage Au g/t Au oz
Nus NUS 152,181 3.057 14,958
Guaico GCO 10,014 8.194 2,638
Footwall-05 GCFW5 9,266 9.819 2,925
Footwall-03 GCFW3 17,745 6.929 3,953
Vega VEGA 2,132 13.755 943
La Manuela-01 MNL_1 1,088 4.766 167
Guayabito GBY 211,887 7.268 49,511
Papi PAPI 20,338 3.345 2,187
Total Indicated 424,652 5.661 77,282

Total Measured + Indicated Resource Estimates for Cisneros Project

Deposit Name Code Tonnage Au g/t Au oz
Nus NUS 353,058 3.337 36,640
Guaico GCO 36,478 7.711 8,749
Footwall-05 GCFW5 22,861 9.783 6,957
Footwall-03 GCFW3 29,665 7.183 6,628
Vega VEGA 2,132 13.755 912
La Manuela-01 LMN1 2,221 5.006 346
Guayabito GYB 258,258 7.345 59,003
Papi PAPI 23,930 3.888 2,894
Total Measured + Indicated 728,603 5.389 122,129

Total Inferred Resource Estimates for Cisneros Deposits

Deposit Name Code Tonnage Au g/t Au oz
Nus NUS 103,445 2.984 9,924
Guaico GCO 6,069 8.059 1,572
Footwall-05 GCFW5 6,213 12.628 2,522
Footwall-03 GCFW3 11,007 9.171 3,245
Vega VEGA 5,533 13.364 2,378
La Manuela-01 MNL_1 1,128 3.140 114
Guayabito Sur GBY-SUR 57,973 7.535 14,044
Guayabito GBY 232,911 8.075 60,468
Papi PAPI 111,932 4.201 15,120
Total Inferred 536,211 6.345 109,388
  1. Mr. Edgard Vilela, is the Qualified Persons and Chartered Professional for the Mineral Resource estimate. The effective date of the estimate is September 24, 2017.
  2. Mineral Resources are reported using a cut-off grade of 2.95 g/t Au for GCO, GCFW3, GCFW5 and MNL_1.
  3. Mineral Resources are reported using a cut-off grade of 1.66 g/t Au for NUS and 1.50 for PAPI.
  4. Mineral Resources are reported using a cut-off grade of 2.62 g/t Au for GYB-SUR and 2.50 for GYB.
  5. Reported Mineral Resources contain no allowances for hanging wall or footwall contact boundary loss and dilution. No mining recovery has been applied.
  6. Rounding as required by reporting guidelines may result in apparent summation differences between tonnes, grade and metal content.

 Underground Mining

The base case scenario for the Project includes mining of measured, indicated, and inferred mineral resources with underground Cut and Fill ( C&F ) and Longhole Open Stoping mining methods.

Preliminary assumptions for Cut and Fill Mining method is that it is a selective mining process. The dilution for veins lower than 0.8 metres in width were not considered as part of the block modelling process for veins on Cisneros projects. Block model are diluted to 0.8 m and no additional dilutions were considered for the mine plan in these preliminary evaluations.

The mining recovery factor is depended on results of rock mechanics studies. For every 100 vertical metres it is suggested to leave a nine metre horizontal pillar which will be dependent on the vertical extent of each vein’s geometry. The following table shows the dilution and mining recovery factor for C&F mining based on specific calculations that were considered for dilution and mining recovery factors during mine plan scheduling.

Mining Recovery Factor for Cut and Fill mining

Assumptions Guaico Veins FW3 Vein FW5 Vein
Dilution on veins < to 0.8 m thickness 0% 0% 0%
Mining Recovery Factor 96.7% 93% 93.3%

A mining recovery of 92% is assumed for longhole open stoping Mining. The mining recovery factor is depended on rock mechanics recommendations. Again it is suggested to leave a nine metre horizontal pillar for every 100 vertical metres.
Process Plant

The objective of the metallurgical process is to obtain gravimetric concentrates and flotation concentrates in a plant with a capacity of 500 tonnes per day (tpd). The plant will be composed of a single production line in two conventional processes namely gravity followed by flotation to obtain sulphide concentrates containing gold.

The process plant has been designed to operate 347 days per year and treat 500 tonnes of material daily. The average head grade is estimated to be 6.43 g/t Au and an overall recovery of 90% is anticipated. Mineable resources have been estimated at 784,763 tonnes with a life-of-mine ( LoM ) of five years. A stockpile of 19,402 tons, resulting from development of stopes in the Guayabito and Guaico-Nus areas will be maintained for the commissioning of the plant.

The general flow sheet of the plant process consists of four sections to produce gold concentrates. These include primary and secondary crushing, grinding and gravity, flotation and concentrate filtration.

Capital and Operating Costs

The total preproduction and sustaining capital cost estimated for the Cisneros project is US$ 75.5 M and includes expenses incurred from 2014 to March 2018. Preproduction capital cost is US$ 61.5 M and sustaining capital cost is US$14.1 M.  Capital costs include a contingency of 15% (US$ 7.8 M).

The capital cost profile for the Cisneros Project includes pre-production and sustaining capital. Sustaining capital includes expenses incurred during the expected production period of April 2018 to 2022. All capital costs were estimated for a 3,000 tonnes per month mill capacity.

Economic Analysis and Cash Flow Results

A pre-tax and post-tax cash flow model was developed for the Cisneros project. The financial evaluation presents results for Net Present Value (“NPV”), Internal Rate of Return (IRR) and payback period. All the evaluations include only CAPEX and Sustaining capex from 2017 to LoM and a contingency of 15%. Capital expenditures prior to 2017 of US$13.2 M are included as indicated in the audited financial statements of Antioquia for 31-Dec-2016. The results show that the project has a pre-tax IRR of 24.0% and pre-tax NPV of $23.7M and post-tax IRR of 18.7% and post-tax NPV of $16.7 M.

Cisneros Gold Project economic model summary

Descriptions Input / Output Units Value
Financial Input   
Price  US$/oz 1250
Exchange Rate COP:USD 2910
Discount Rate % 5.0
Processing Schedule 
Total Ore Milled k-tons 785
Au Grade g/t 6.4
Au Recovery % 0.93
Recovered Au k-oz 150.9
Payable Au k-oz 147.3
Capital Cost
Sustaining Capex US$ M (12.22)
Capex 2017-LoM US$ M (39.80)
Total Capex 2017-LoM US$ M (52.02)
Contingency US$ M (7.80)
Total Capex 2017-Lom US$ M (59.82)
Capex previous to 2017 US$ M (15.71)
Pre-Tax CF
Undiscounted pre-Tax Cash Flow US$ M 33.54
Pre-tax IRR % 24.0%
Pre-tax NPV (5%) US$ M 23.71
Payback year 2.60
Post-Tax CF
Undiscounted post-Tax Cash Flow US$ M 25.58
Post-tax IRR % 18.7%
Post-tax NPV (5%) US$ M 16.75
Payback year 3.20

Cash costs of production are estimated at US$697 /oz with all in costs including closure and capital costs estimated at US$1,146 /oz

Operating Cost Analysis

Expenses US$ (M) Unit Cost US$/oz
On Site Mining Cost 74.61 506.5
On Site Mining G & A Cost 11.30 76.7
Royalties 7.06 47.9
Social and Permit Cost
Smelting, Refining and Transport 9.74 66.1
Cash Cost 102.71 697.3
Closure Cost 1.55 10.6
Sustaining Capital 14.05 95.4
All-in sustaining costs AISC 118.31 803.2
Preproduction Capital expenses 50.56 343.3
All in costs AIC 1146.5

Sensitivity Analysis

The NPV is most sensitive to metallurgical recovery, gold price and gold grade and less sensitive to OPEX and CAPEX.

Cisneros Project Post-Tax @ 5% NPV Sensitivity Analysis

% Variations Price
Au Grade
Exchange Rate
70% -24.2 32.8 30.7 -25.3 15.6 -25.3
80% -8.3 27.4 26.0 -9.0 16.1 -9.0
90% 5.4 22.1 21.4 5.1 16.5 5.1
100% 16.7 16.7 16.7 16.7 16.7 16.7
110% 28.0 11.4 12.1 28.3 17.0 25.4
120% 39.3 6.0 7.5 39.9 17.2 25.4
130% 50.3 0.4 2.8 51.0 17.3 25.4

Subsequent Drilling after PEA Effective Date

During the preparation of the PEA an exploration campaign was carried out with diamond drilling from surface. A total of 2,912.00 meters were drilled in the areas of Guayabito, Nus and Guaico. 2,344.20 metres of drilling were included and reported in the PEA and 567.80 meters were not reported in the PEA as results were obtained after the effective date of the PEA.  AGD’s management believes the results of these drillholes will not materially impact the PEA results.

Drill Hole Highlights

Drill Hole From (m) To (m) Length (m) True Width (m) Au ppm
GCO17-038 101.00 101.50 0.50 0.29 12.34
GCO17-038 109.80 111.00 1.20 0.69 1.59
GCO17-038 135.50 136.30 0.80 0.44 2.23
NUS17-011 98.20 99.20 1.00 0.48 2.28
NUS17-012 119.00 120.00 1.00 0.54 2.82
NUS17-013B 101.40 102.00 0.60 0.33 1.03

Drill Hole Specifications

NUS17-011 485595.85 721979.64 1456.93 120.00 178.00 -59.00
NUS17-012 485533.97 721979.01 1495.25 122.30 178.00 -59.00
NUS17-013B 485481.97 721979.10 1530.36 170.50 174.00 -60.00
GCO17-038 485910.28 722270.36 1301.74 155.00 129.60 -55.00
Exploration Potential

Antioquia Gold has identified six other exploration targets on its Cisneros land package using geochemical sampling and geophysics that have a similar signature to the Guaico-Guayabito area. The company intends to continue exploring and to start drilling using cash flow from mining operations.
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This page was created on Tue Jan 22, 2019 at 6:20:01 PM Pacific Time.