A NI 43-10 Technical Report on Preliminary Feasibility Study was prepared by SRK Consulting (U.S.), Inc. The Technical Report is based on the updated Mineral Resource and Mineral Reserve estimates for the Marmato Expansion Project with an effective date of March 17, 2020.

Mineral Resources

A total of 1,357 drill holes were used to inform the March 17, 2020 Mineral Resource Estimate (MRE), including historic drilling and more recent drilling completed between the 2019 Preliminary Economic Assessment (PEA) and the 2020 Pre-Feasibility Study (PFS).

Marmato mine Mineral Resource Statement, March 17, 20201

Area Category Tonnes (Mt) Grade Au (g/t) Grade Ag (g/t) Contained Au (koz) Contained Ag (koz)
Marmato Upper Mine2,5 (Veins) Measured (M) 2.1 5.65 27.0 387 1,853
Indicated (I) 9.2 4.45 18.7 1,320 5,545
M&I 11.4 4.67 20.2 1,707 7,397
Inferred 4.5 3.70 15.5 532 2,224
Marmato Upper Mine3,5 (Transition) Measured (M) 0.0 0.0 0.0 0.0 0.0
Indicated (I) 3.4 2.68 7.2 294 785
M&I 3.4 2.68 7.2 294 785
Inferred 0.0 1.95 3.7 2 3
Lower Mine4,6 Measured (M) 0.0 0.0 0.0 0.0 0.0
Indicated (I) 24.7 2.63 3.6 2,085 2,870
M&I 24.7 2.63 3.6 2,085 2,870
Inferred 21.9 2.32 2.1 1,639 1,506
Marmato total Measured (M) 2.1 5.6 27.0 387 1,853
Indicated (I) 37.3 3.1 7.7 3,699 9,200
M&I 39.4 3.2 8.7 4,086 11,053
Inferred 26.4 2.6 4.4 2,172 3,733

Notes:

1 Mineral Resources are reported inclusive of the Mineral Reserve. Mineral resources are not mineral reserves and do not have demonstrated economic viability. All figures are rounded to reflect the relative accuracy of the estimate. All composites have been capped where appropriate. The Mineral Resources were estimated by Benjamin Parsons, MSc, MAusIMM #222568 of SRK, a Qualified Person pursuant to NI 43-101.
2 Upper Mine is defined as the current operating mines from levels 16 through 21 using existing mining methodology (cut and fill).
3 “Transition Zone” is defined as mining of Deep Zone above an elevation of 950 m (accessed from the current operations) using a modified longhole stoping method.
4 The Lower Mine is defined as mining of Deep Zone below an elevation of 950 m using longhole open stope mining methods.
5 Porphyry and vein mineral resources are reported at a CoG of 1.9 g/t. CoGs are based on a price of US$1,500/oz Au and gold recoveries of 90% for underground resources without considering revenues from other metals.
6 The Lower Mine mineral resources are reported at a CoG of 1.3 g/t. CoGs are based on a price of US$1,500/oz Au and gold recoveries of 95% for underground resources without considering revenues from other metals.
Source: SRK, 2020

Mineral Reserves

Mineral Reserves were classified using the 2014 CIM Definition Standards. Indicated Mineral Resources were converted to Probable Mineral Reserves by applying appropriate modifying factors to potential mining shapes created during the mine design process. In the same manner, Measured Mineral Resources were converted to Proven Mineral Reserves.

Marmato mine Mineral Reserve Estimate, March 17, 20201

Area Category Tonnes (kt) Au (g/t) Ag (g/t) Contained Au (koz) Contained Ag (koz)
Marmato Upper Mine2 (veins) Proven 762 5.01 21.80 123 534
Probable 3,049 4.20 16.85 412 1,652
Total 3,812 4.37 17.84 535 2,186
Marmato Upper Mine3 (transition) Proven 40 7.63 28.16 10 36
Probable 1,293 3.43 7.92 143 329
Total 1,333 3.56 8.52 152 365
Lower Mine4 Proven - - - - -
Probable 14,556 2.85 3.84 1,333 1,799
Total 14,556 2.85 3.84 1,333 1,799
Marmato total Proven 802 5.14 22.12 133 570
Probable 18,898 3.11 6.22 1,888 3,780
Total 19,700 3.19 6.87 2,021 4,350

Notes:

All figures are rounded to reflect the relative accuracy of the estimates. Totals may not sum due to rounding. Mineral Reserves have been stated on the basis of a mine design, mine plan, and economic model. Mineral Resources are reported inclusive of the Mineral Reserve.

1 Marmato Upper Mine veins reserves are reported using a CoG of 2.23 g/t Au. The Marmato Upper Mine veins CoG calculation assumes a US$1,400/oz Au price, 85% Au metallurgical recovery, US$49.45/t mining cost, US$13.63/t G&A cost, US$12.24/t processing cost, and US$8.96/t royalties. Upper Zone Transition Zone reserves are reported using a CoG of 1.91 g/t Au. The Marmato Upper Mine transition zone CoG calculation assumes a US$1,400/oz Au price, 95% Au metallurgical recovery, US$46/t mining cost, US$13.63/t G&A cost, US$12.24/t processing cost, and US$8.96/t royalties. Lower Mine reserves are reported using a CoG of 1.61 g/t Au. The Lower Mine CoG calculation assumes a US$1,400/oz Au price, 95% metallurgical recovery, US$42/t mining cost, US$14/t processing cost, US$6.75/t production taxes, US$3/t G&A cost, and US$3/t tailings cost. Note that costs/prices used here may be somewhat different than those in the final economic model. This is due to the need to make assumptions early on for mine planning prior to finalizing other items and using long-term forecasts for the life-of-mine plan.
2 The Marmato Upper Mine veins area is currently mined using cut-and-fill methods. Mining dilution ranging from 20% - 55%, averaging 26%, is included in the reserves using a zero grade for dilution. A mining recovery of 90% is applied to stopes. The Marmato Upper Mine veins Mineral Reserves were estimated by Fernando Rodrigues, BS Mining, MBA, MMSAQP #01405, MAusIMM #304726 of SRK, a Qualified Person.
3 The Marmato Upper Mine transition zone area will be mined using a modified longhole stoping method. A mining dilution of 7% is included in the reserves using a zero grade for dilution. A mining recovery of 90% is applied to stopes. The Marmato Upper Mine transition Mineral Reserves were estimated by Fernando Rodrigues, BS Mining, MBA, MMSAQP #01405, MAusIMM #304726 of SRK, a Qualified Person.
4 The Lower Mine portion of the Project will be mined by longhole open stoping mining methods. Mining dilution (internal and external) is included in the reserve. Stope dilution is 8%, and a portion of the stope dilution is applied using grade values based on average surrounding block information. A mining recovery of 92.5% is applied to stopes. The Lower Mine Mineral Reserves were estimated by Joanna Poeck, BEng Mining, SME-RM, MMSAQP #01387QP, a Qualified Person.
Source: SRK, 2020