The Chuquicamata district includes the Chuquicamata and Radomiro Tomic megadeposits, the exotic copper deposit Mina Sur, the newly developed Ministro Hales mine (formerly known as Mansa Mina) located 5.5 km south of Chuquicamata, and the deposits of the Toki cluster (Toki, Genoveva, Quetena, Miranda, and Opache) located about 15 km SSW of Chuquicamata. Total identified resources for the Chuquicamata district are estimated at 107.4 Mt of fine copper considering a cutoff Cu grade of 0.2 wt% (Codelco Memoria Anual 2011). Inferred resources for the cluster are estimated at about 20 Mt of fine copper, with Toki contributing with ca. 11.2 Mt and Quetena with ~3.8 Mt (Camus 2003; Rivera et al. 2006).

The deposits of the district are located in the Late Eocene–Early Oligocene (43–31 Ma) porphyry copper belt that extends for about 1,400 km, from 18°S to 31°S (Sillitoe 1988; Sillitoe and Perelló 2005). The rocks in the area range in age from Paleozoic to Tertiary. The main structural feature observed is the West Fault, which is part of the Domeyko Fault System (Boric et al. 1990; Dilles et al. 1997) and divides the district in two domains: an eastern domain and a western domain.

The main copper oxide minerals in the Radomiro Tomic deposit are atacamite, copper clays, chrysocolla, and copper wad. Their relative abundance provides the basis for dividing the oxide zone into two major geologic units: the Upper Oxide unit and the Lower Oxide unit. Furthermore, the study of mineral abundances in the oxide zones allowed the definition of an oxide mineral zonation that consists of five mineral assemblages, based on the relative proportion of the three main copper oxide components: atacamite, copper clays, and chrysocolla. These classifications allow both an understanding of the distribution of copper minerals throughout the zone and an interpretation of the supergene processes that formed it.

The Upper Oxide unit is mineralogically heterogeneous. The copper content is furnished, on average, by 40 vol percent atacamite, 31 vol percent copper clays with minor chysocolla and copper wad. The Lower Oxide unit is more homogeneous. Atacamite accounts for 70 vol percent of the copper ore minerals with minor amounts of copper clays and chrysocolla. Copper and chlorine concentrations and porosity are greater in the Upper Oxide unit, whereas hematite, chalcocite, and molybdenite concentrations and specific gravity are greater in the Lower Oxide unit.

The vertical distribution of the Cl/Cu ratio shows a chlorine-deficient zone located between elevations of 2,780 and 2,870 m. Between these elevations, the proportion of atacamite is lower and the proportion of copper clays, chrysocolla, and copper wad is higher than in other portions of either the Upper Oxide or Lower Oxide units. [2001, Oxide Mineralization at the Radomiro Tomic Porphyry Copper Deposit, Northern Chile P.1]

In 2019, the historic Chuquicamata deposit began to ramp down production in the open pit make the shift to a high-tech underground mine operation. [Annual Report 2019. P. 19]

Chuquicamata Subterránea will transform the century-old Chuquicamata open-pit mine, the largest in the world, into a modern large-scale underground operation using the block caving method of exploitation, extending the life of the division by at least 40 years.

The Chuquicamata Division predominantly sulfide concentrates that are smelted and refined largely on site to yield electro-refined and electro-won copper cathodes.

Sulphide ore is processed in the concentrator. The mill employs two 32-ft SAG mills feeding a complex arrangement of rod and ball mills. A final grind size of 219 microns is achieved before the slurry is passed on to flotation.

The mill head grade for sulfide processing is approximately 0.8% Cu and also contains significant amounts of molybdenum making two separate concentrates viable. The final copper concentrate is smelted and then refined prior to shipment.

The concentrator contains a separate circuit for recovery of copper from the on-site smelter slag. Slag can contain between 8 and 10% Cu and is sent to its own process line containing a SAG mill two ball mills, and floatation circuit.

The Chuquicamata mine’s smelting process involves two stages: a smelting stage and a convers ........