La Colosa mine

La Colosa is a porphyry gold mine in Colombia. The mine is located in Cajamarca, Tolima on the eastern flanks of the Central Ranges of the Colombian Andes. La Colosa has estimated inferred resources of of gold, grading at of Au. In 2015, the mine produced of gold. In 2016, 88.4% of the mining value in Colombia came from coal and gold combined, with nickel following at 9.3%.
Description.
La Colosa, covering an area of , is the second major greenfield discovery in Colombia, after Gramalote and believed to have a potential of producing between of gold per year for 20 years. La Colosa gold project, started in 2006, is based on low-grade porphyry copper deposits containing a small amount of gold. Gold grains in the deposit are found both liberated and locked in sulphides and silicates. The gold mineralization in the deposit is attributed to porphyry intrusions into the Paleozoic schists of the Cajamarca Complex on the eastern flank of the Central Ranges of the Colombian Andes, around 8 Ma. Gold mineralization is believed to have occurred over three early phases of intrusion, which are accompanied by a series of potassic and sodic-calcic alteration events and a late phase of dacite porphyry intrusions.