The deposit lies within the late Miocene aged El Boleo Formation within fine to coarse clastic sedimentary rocks that were deposited in the late Miocene in deltas and near-shore shallow marine basins.

The deposit, which occurs in Boleo formation, consists of several mineralized groups called “Mantos” (manto is a specific Spanish term used in mining parlance for mineralized layer or stratum). In general, each mantos is distinct in terms of copper-cobalt ratio and relative zinc, manganese and carbonate concentrations. Mineralization is finely disseminated in the slump breccias over up to 20m thick intervals.

The project is an underground and surface mining operation to provide run-of-mine ore to a fully integrated hydrometallurgical facility. Integrated underground mining which comprise short wall and room and pillar method using continuous miners along with small cuts open mining techniques are to be employed. The mine plan will be continuously optimized on the basis of resource update by additional drilling and operational condition with the aim of maximizing economics.

The Boleo ores are clayey and generally fine grained and easily broken. The milling circuit design takes material from the ROM pad into a static grizzly with the oversize to a primary crusher. The combined product is then scrubbed in copper solvent extraction raffinate. The scrubber product is screened with the oversize sent to a secondary crusher. The combined product goes to the ball mill sump before cycloning. The coarse cyclone product is directed to the ball mill. Milling is conducted in raffinate.

The milled product is heated to a target temperature of 80ºC for atmospheric leaching. Leaching proceeds in two steps: acid, oxidative leaching with manganese dioxide oxidation for leaching of Cu, Zn and Co sulphides and: acid reductive leaching with addition of sulphur dioxide gas to reduce residual manganese dioxides. The reductive leaching of surplus manganese dioxide is essential for maximizing the extraction of cobalt.

The slurry from oxidation and reduction l ........