La Mina Mine, Colombia

According to the updated PEA, the project is estimated to produce 1.29 million ounces of gold, 203.9 million pounds of copper and 2.98 million ounces of silver over an estimated mine life of 11.2 years.

Initial capital expenditure for the mining operation is estimated to be $425m. Sustaining capital and mine closure expenditures are projected to be around $203m.

La Mina Project Location

The La Mina Project is located in the Department of Antioquia, Republic of Colombia. The site is around 51km southwest of Medellin, the capital of the province.

The mining project includes two concession contracts and two concession contract applications covering an area of 3,210 hectares.

The project area is located on the eastern slopes leading up from the Cauca River, in tropical mountainous topography at an average elevation of approximately 1,700m.

Geology and Mineralisation

The La Mina property is located within the Middle Cauca Belt of Miocene-age volcano-plutonic rocks of central Colombia. The Middle Cauca Belt is known to contain multiple significant porphyry golds or copper-gold disseminated deposits.

The area around the La Mina Project is underlain by country rocks consisting of a series of basaltic volcanic rocks, sedimentary rocks of the Amagá Formation, and upper Combia Formation of basalts and andesitic basalts interlayered with volcaniclastic rocks and coarse-grained sedimentary rocks.

The intermediate composition volcanic rocks of the Combia Formation and the sub-volcanic breccias and related shallow level porphyries that intruded the Combia Formation host the porphyry-related gold, copper, and silver mineralisation.

The PEA for the project considers mining and processing of mineralised material from all the resource areas of the project- La Cantera, La Garrucha and Middle Zone.

La Cantera and Middle Zone include two of the four drill-tested mineralised porphyry intrusive and breccia bodies on the La Mina project. The intrusive centres in both deposits feature porphyry stocks and breccias that make up porphyry copper-gold deposits.

Mineralisation in the La Garrucha is similar to La Cantera and Middle Zone prospects.

La Mina Mineral Resource Estimate

As of December 2022, La Mina Mineral Resource Estimate in the Indicated category is 33.77Mt grading 0.73 g/t gold, 2.08 g/t silver, 0.21% copper or 1.06 g/t gold equivalent at 0.30 g/t cut-off.

In the Inferred category, the figure stands at 56.23Mt grading 0.58 g/t gold, 2.32 g/t silver, 0.14% copper or 0.80 g/t gold equivalent at 0.30 g/t gold cut-off.

Mining and Ore Processing

According to the PEA, conventional open pit mining methods to mine at La Mina project. This will include using surface drill and blast techniques and deploying off-highway haul trucks and front-end loaders for the operations.

The La Cantera pit is the nearest to the processing plant, making it the ideal location to commence mining. The pit also contains the highest-grade material.

Middle Zone will also be mined along with the La Cantera pit. After completion, the Middle Zone will be backed filled as a waste rock storage facility.

Mining at La Garrucha, which is farthest from the plant, will start at a later stage.

The mineralised material from the La Cantera and the Middle Zone open pits is planned to be processed in a 15,000 tonnes per day (tpd) conventional concentrator to produce a copper concentrate with gold as a by-product.

Initially, the ore will be crushed and ground to separate minerals. The process plant will include a Froth flotation circuit to recover most of the copper-bearing minerals along with most of the gold into a high-grade copper/gold concentrate.

Cyanide leaching and gold adsorption/desorption circuit will extract the gold from the flotation tailings streams onto activated carbon.

The tailings will be pumped to the tailings storage facility (TSF).

Key Infrastructure and Accessibility

Electric connection to the gold-copper-silver mine will not be an issue due to the project’s proximity to Medellin. The La Mina Project lies within a few kilometres away from a 200kV power substation.

The project can be accessed on a paved highway 30km southwest of Medellin to the junction with an 11km gravel road that leads to the property.

Water required for project operations will be procured from seasonal and year-round streams.

Contractors Involved

Resource Development Associates and PMet Services prepared the National Instrument 43-101 (NI 43-101) Preliminary Economic Assessment (PEA) for the La Mina Project.

GEOVIA Whittle software was used for pit optimisation.