The Los Bronces deposit is part of the Miocene Pliocene Río Blanco – Los Bronces porphyry copper system with mineralisation extends 9km from North to South and 3km from East to West. The deposit is open at depth and laterally.

The main ore body is a complex assemblage of hypogene copper-molybdenum sulphide breccia hosted mineralisation that was subsequently overprinted by surface-related supergene processes. The hypogene sulphide mineralisation shows a close relationship with the intrusion of porphyry dykes and sills, development of large-scale alteration zones, vein development, and breccia emplacement. The ore body is related to at least seven hydrothermal breccia pipes forming a large elliptic body of 2km in length, 0.7km wide and 1.0km in depth. The shape of the breccia system is ‘funnel-like’, characterised by sharp contacts with the host rocks in the upper part of the column and transitional at depths.

The host rocks are the volcanic sequence of the Farellones Formation and the plutonic rocks of the San Francisco Batholith which intrude the Farellones Formation. Copper mineralisation is associated with the emplacement of a complex system of porphyry intrusions (quartz monzonites and quartz monzodiorites) and hydrothermal breccias. Early copper and molybdenum mineralisation is hosted in the porphyry stock, in high-grade breccia bodies and is disseminated throughout the bordering country rocks.

The bulk of the copper and molybdenum rich Los Bronces ore, is crushed and milled by two plants, Los Bronces and Confluencia. The resultant slurry is then transported through a pipeline to the Las Tórtolas flotation plant located 35km north of Santiago where copper and molybdenum concentrates are produced. A proportion of lower grade ore is place on dump leach pads from which copper cathodes are produced via leaching, solvent extraction and electrowinning (SX/EW) processes at the San Francisco plant.