The Zaldívar porphyry copper deposit is situated on the western margin of the Atacama Plateau in northern Chile. The deposit is part of a large Tertiary porphyry copper system which includes the scondida porphyry copper deposit. This porphyry complex occurs within the large West Fissure structural system which controls most of the large porphyry copper deposits in Chile. The Zaldívar porphyry system is at the intersection of the West Fissure and a series of Northwest and Northeast striking faults. The deposit is generally centered on a Northeast striking granodiorite porphyry body that intrudes andesites and rhyolites, and cuts across the north-south striking Portezuelo fault. Although the geology and the Zaldívar mineral deposit are generally continuous from east to west, the orebody was arbitrarily divided into two zones: the Main zone (area east of 93,000E) and the Pinta Verde zone (area west of 93000E).

The Zaldívar orebody contains both sulfide and oxide copper mineralization. The majority of the copper occurs in a blanket of oxide (covering an area of approximately 2 kilometers by 1.5 kilometers with an average thickness of approximately 90 meters) and secondary sulfide ore (covering an area of approximately 2.5 kilometers by 1.5 kilometers with variable thickness from a few meters in the southwest extremity to over 300 meters in the northeast extremity) which overlays deeper primary sulfide mineralization of lower grade. The economically important mineralization types are secondary sulfide (chalcocite), oxide (brochantite and chrysocolla) and a mixed mineralization type of combined sulfide and oxide copper minerals. Primary sulfide mineralization consists of pyrite, chalcopyrite, bornite and molybdenite.

In the Main zone orebody, to the east of the Portezuelo fault, rhyolite is the host rock and secondary sulfide mineralization is dominant (85% to 90%) with the balance of the copper present as oxide minerals. West of the fault, andesite and granodiorite are the host rocks and the copper is present as a mixture of both oxide and secondary sulfide minerals.

The Zaldívar Mine is a traditional open pit truck/shovel operation. The ultimate pit will measure approximately 2.8 km east to west, 2.6 km north to south, and have a maximum depth of approximately 630 m. Waste and ore are mined on 15 m benches.

Zaldívar is an open-pit, heap-leach copper mine which produces copper cathodes using the solvent extraction and electrowinning (SX-EW) process.

Pure cathode copper is produced by three stages of crushing and stacking of ore, followed by heap leaching and bacterial activity to remove the copper from the ore into solution. Run of mine dump leach material is placed on the old sulfide ore pad, and is also leached. A solvent extraction and electro-winning process then removes the copper from solution and produces the cathode copper. A flotation plant is also used to recover copper, in the form of copper concentrate, contained in the fine material produced in the tertiary crushing process. The heap leach cycle time is approximately 330 days.

Zaldívar Chloride Leach

In December 2019, the Board of Compañía Minera Zaldívar approved the Chloride Leach Project. The project contemplates the construction of a chloride dosing system, an upgrade of the solvent extract ........