The Project considers open pit mining of 21.7 million tonnes of ore from the La Pava and Quema-Quemita pits and will be developed in multiple phases. Ore will be crushed to 80% passing 105 mm in a single stage jaw crusher. Lime will be added to the crushed ore for pH control before being conveyor stacked and leached with a dilute cyanide solution. Pregnant leach solution will flow by gravity to a pregnant solution pond and will then be pumped to an ADR (Adsorption, Desorption, Recovery) plant for recovery of metal values. Gold and silver will be loaded onto activated carbon (Adsorption) and then periodically stripped from the carbon in a desorption circuit (Desorption), electrowon (Recovery) and smelted to produce the final doré product.
Based on an ore processing rate of 10,000 tonnes per day or 3.65 million tonnes per year, the Project has an estimated six-year mine life.
The Project’s low stripping ratio, high gold recoveries, and low operating costs all contribute to a low estimated AISC of $626 per ounce of gold.
The PFS was prepared by a team of independent industry experts including Kappes, Cassiday and Associates (“KCA”), Moose Mountain Technical Services (“Moose Mountain” or “MM”), Resource Geosciences Incorporated (“RGI”), Anddes Asociados (“Anddes” or “AA”), HydroGeoLogica, Inc. or (“HGL”), and Linkan Engineering (“Linkan” or “LE”) with input from other consultant groups.
|Cerro Quema Prefeasibility Study Highlights||Units||Values|
|Throughput Rate per Day||tonnes||10,000|
|Total Ore to Leach Pad||M tonnes||21.7|
|Gold Grade (Average)||g/t||0.80|
|Silver Grade (Average)||g/t||2.2|
|Average Gold Recovery||%||87%|
|Average Silver Recovery||%||26%|
|Average Annual Gold Production||ounces||81,000|
|Strip Ratio ||waste : ore||0.66|
|Initial Capex||US$ million||$164|
|Avg. Life of Mine Operating costs||$/t ore processed||$10.34|
|Total Cash Cost (net of by-product credits)1 ||$/oz Au||$511|
|All-In Sustaining Cost (“AISC”)1||$/oz Au||$626|
|Pre -Tax - NPV (5% discount rate)||US$ million||$233|
|After-Tax - NPV (5% discount rate)||US$ million||$176|
1 Total cash cost and AISC are non-GAAP measures and are net of silver credits and includes royalties payable. See reference below regarding non-GAAP measures.
* All dollar amounts in US dollars
- Caballito Cu-Au Zone
- A new zone at Caballito comprised of low-arsenic copper-gold mineralization located south of the Quemita reserve was discovered in 2017.
- 650 to 800 metre long, 350 to 400 metres wide northwest-southeast trending chargeability anomaly outlined in a 2017 IP survey.
- Widths in excess of 100 metres grading better than 1% Cu and 0.2 to 0.4 g/t Au in drill holes.
- IP shows a similar, but steeper dipping, chargeability that could be a down-faulted continuation of the same mineralization to the northwest.
- Re-examination of core from sulphide intercepts below the Quemita oxide gold reserve (1.2 km to the northwest) have found indications of Caballito style copper-gold mineralization with low arsenic. (There are other gold in oxide and copper-gold sulfide targets on the 15,000 hectare concession.)