Monster copper mines of Chile: stories from Chuquicamata

Chile is the world’s largest copper producer: 40% of the known copper resources of the world, 24% of the global copper production, and about 5 million metric tons produced annually. Chile primarily exports to China, Japan, Europe, India. Copper mining in Chile is associated with an enormous transportation and energy infrastructure: two main shipping ports (Antofagasta and Mejillones), a 770km-long railway network, roads, fields of wind turbines and solar panels, and a pile of thermoelectric plants.

The above numbers are totally mind-blowing, and every Chilean geologist agrees to say that this enormous amount of mineral wealth is a geological anomaly. All of Chile’s mineral deposits are formed as a result of the country’s geographic position at the margin of a continental tectonic plate, bounded by an active subduction zone to the west. Copper is primarily extracted from giant porphyry copper-molybdenum deposits, formed during five consecutive magmatic and mineralization events in the past 200 million years (Jurassic to Oligocene). In addition, the extremely arid conditions in the northern half of Chile for the past 10 million years have contributed to emphasizing the volume of copper mineralization, through a phenomenon known as “supergene enrichment”. In other words, Chilean copper deposits were already big to start with, and they got even bigger.

Copper mining in Chile occurs at all scales: small scale artisanal mines operated by “pirquineros”, medium-scale mines, and absolute monsters, including both underground (eg: Escondida) and open pit mines. Chuquicamata is the largest open pit mine in the world, with unreal dimensions of 6,5 km long, 4 km wide, and 1,5 km deep. Chuquicamata is not only a mine, it is a concentrate of 120 years of Chilean mining history and human stories. Today, the former mining town of Chuquicamata, near Calama, is half buried under the mine tailings as a result of the mine expansion.