Soto Norte mineral resources, effective May 22, 2019 (100% basis)

Classification

Tonnes
(kt)

Au
(g/t)

Au
(koz)

Ag
(g/t)

Ag
(koz)

Cu
(%)

Cu
(klb)

 

AuEQ
(g/t)

AuEQ
(koz)

Indicated

 48,062

 5.47

 8,454

 35.8

 55,324

 0.18

 193,422

 

 6.35

 9,818

Inferred

 27,343

 4.06

 3,571

 25.9

 22,754

 0.18

 107,281

 

 4.83

 4,249

Notes:

(1) 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 and have been used to derive sub-totals, totals and weighted averages. Such calculations inherently involve a degree of rounding and consequently introduce a margin of error. Where these occur, SRK does not consider them to be material. All composites have been capped where appropriate. Indicated Mineral Resources are inclusive of those Mineral Resources modified to produce Mineral Reserves; that is, they are reported on an ‘inclusive basis’. The Concession is wholly owned by and exploration is operated by Sociedad Minera de Santander S.A.S (Minesa).

(2) The standard adopted in respect of the reporting of Mineral Resources for the Project, following the completion of required technical studies, is in accordance with the NI 43-101 guidelines and the 2014 CIM Definition Standards and have an Effective Date 22 May 2019.

(3) SRK reasonably expects the Soto Norte deposit to be amenable to a variety of underground mining methods. Mineral Resources are reported based on an NSR cut-off which considers marginal mining costs, processing costs, and G&A costs totalling USD47/t. The NSR cut-off calculation has been determined based on metal price forecasts, metallurgical recovery assumptions from initial testwork, mining costs, processing costs, general and administrative (G&A) costs, and other NSR factors. The final NSR calculation is based on average assumptions for the deposit and determined using NSR (USD) = 36.1759 x (gold grade g/t Au) + 0.4426 x (silver grade g/t Ag) + 0.0046 x (copper grade ppm Cu) – 4.5752 x (sulphur grade %S) - 0.0037 x (arsenic grade ppm As) - 0.0082 x (antimony grade ppm Sb) - 0.0065 x (bismuth grade ppm Bi) – 0.0067 x (cadmium grade ppm Cd) – 0.277 x (mercury grade ppm Hg) – 0.0001 x (zinc grade ppm Zn) -0.02. Metal price forecasts considered for the calculation of metal equivalent grades are Gold (USD1,300/oz), Silver (USD18/oz), Copper (USD6,800/t). NSR cut-off calculations assume average metallurgical recoveries of: Gold (92%), Silver (92%), Copper (76%). A Gold Equivalent (AuEQ) grade and contained ounces has been separately included in the mineral resource estimate based on the NSR formula to determine equivalent values for copper and silver in relation to gold, taking into account process recoveries, metal prices, realisation costs and payabilities for each metal. The gold value used in the AuEQ estimate also carries the full cost of penalty elements.

(4) SRK completed a site inspection of the deposit by Mr. Ben Parsons, MSc. MAusIMM (CP), an appropriate “independent qualified person” as defined in National Instrument 43-101.



Soto Norte mineral reserves, effective January 1, 2021 (100% basis)

Classification

Tonnes

Gold

Silver

Copper

 

Gold Equivalent

 

AuEQ

AuEQ

(kt)

(g/t)

(koz)

(g/t)

(koz)

(%)

(klb)

 

(g/t)

(koz)

Probable

24,767

6.22

4,950

34.4

27,386

0.19

102,868

 

6.95

5,535

Notes:

(1) All figures are rounded to reflect the relative accuracy of the estimate and have been used to derive sub-totals, totals and weighted averages. Such estimates inherently involve a degree of rounding and consequently introduce a margin of error. Where these occur, SRK does not consider them to be material. The Concession is wholly owned by and exploration is operated by Sociedad Minera de Santander S.A.S.

(2) The standard adopted in respect of the reporting of Mineral Reserves for the Project, following the completion of required technical studies, is in accordance with the NI 43-101 guidelines and the 2014 CIM Definition Standards, and have an Effective Date of 01 January 2021.

(3) SRK reasonably expects the Soto Norte deposit to be amenable to a variety of underground mining methods and the mine plan supporting the Mineral Reserve estimate is primarily based on Modified Avoca with additional backfill waste sourced from an underground quarry. Mineral Reserves are reported at an NSR cut-off estimate based on metal price assumptions, metallurgical recovery assumptions from initial testwork, mining costs, processing costs, general and administrative (G&A) costs, and other NSR factors that were estimated at the time of mine planning, totalling USD120/t. The final NSR calculation is based on average assumptions for the deposit and determined using NSR (USD) = 36.1759 x (gold grade g/t Au) + 0.4426 x (silver grade g/t Ag) + 0.0046 x (copper grade ppm Cu) – 4.5752 x (sulphur grade %S) - 0.0037 x (arsenic grade ppm As) - 0.0082 x (antimony grade ppm Sb) - 0.0065 x (bismuth grade ppm Bi) – 0.0067 x (cadmium grade ppm Cd) – 0.277 x (mercury grade ppm Hg) – 0.0001 x (zinc grade ppm Zn) -0.02. Metal price assumptions considered for the calculation of metal equivalent grades: gold (USD1,300/oz), silver (USD18/oz), copper (USD7,000/t). NSR and Cut-off value calculations assume average metallurgical recoveries: gold (92.5%), silver (92%), copper (76%). The NSR cut-off value of USD120/t and production rate of 2.6 Mtpa has been used as the basis for the mine plan supporting the Mineral Reserve estimate. A Gold Equivalent (AuEQ) grade and contained ounces has been separately included in the mineral reserve estimate based on the NSR formula to determine equivalent values for copper and silver in relation to gold, taking into account process recoveries, metal prices, realisation costs and payabilities for each metal. The gold value used in the AuEQ estimate also carries the full cost of penalty elements.

(4) SRK has completed a site inspection of the deposit by Mr Chris Bray BEng MAusIMM (CP), an appropriate “independent qualified person” as defined in National Instrument 43-101.