The Cuajone deposit is considered to be an example of a porphyry copper–molybdenum deposit.

The deposit is approximately 2,300 m long, 900 m wide, and averages 1000 m in thickness. Mineralization has been drill tested to a depth of 2,255 m. The deposit remains open at depth.

Mineralization and alteration at the Cuajone deposit is directly related to a multi-stage latite porphyry that intrudes basaltic andesites and the overlying 370 m of rhyolite porphyries of the Toquepala Group.

The first, pre-mineral intrusive in the mine area, situated approximately 1–2 km to the west of the deposit, was a north–south-elongated, 0.7 x 0.35 km, grey to grey-green holocrystalline to equigranular, medium grained, porphyritic diorite stock. This was followed by emplacement of three latite porphyry stages, producing a 2.5 x 0.7 km, northwest–southeast-elongated intrusive body. The latite multiphase intrusion hosts the mineralization.

The first magmatic pulse of the latite porphyry was concentrated in the southeastern part of the multiple intrusive mass and was responsible for the introduction of the bulk of the hypogene copper and molybdenite mineralization in the Cuajone orebody and the associated intense alteration of both the latite and surrounding Toquepala Group andesites and rhyolites. The intrusion is a porphyry with phenocrysts of quartz to 4 mm in diameter and laths of feldspar in a cryptocrystalline matrix. Alteration takes the form of a potassic core, characterized by biotite-magnetite-K feldspar-silica, grading upwards and outwards to biotitemagnetite-silica, which passes laterally into an extensive outer envelope of chlorite-epidotecalcite-pyrite propylitic alteration which has a radial extent of 4 km from the center of the deposit. The intensity of this alteration has masked the boundary between the latite porphyry and the surrounding Toquepala Group lithologies.

The second intrusive phase formed two bodies, a larger, ovoid 850 x 550 m mass immediately to the northwest of the first pulse, while a smaller 300 x 200 m plug occurs within the outcrop of the first pulse. Both exposures have only weak associated alteration and very minor, lowlevel copper and molybdenum mineralization. Breccia bodies were developed along the intrusive contacts with the other latite pulses and country rocks. These breccias comprise heterolithic clasts that range from well-rounded to angular within a matrix of latite porphyry.

The third magmatic pulse covers a surface area of around 800 m in diameter immediately to the northwest of the main primary latite porphyry outcrop and has only weak associated alteration and no copper or molybdenum mineralization. It is porphyritic with quartz grains up to 2 cm across in a microcrystalline to cryptocrystalline matrix.

At a late stage in the emplacement of the latite porphyry complex, and during an initial erosive period, the interaction of downward-percolating meteoric waters with the rising hypogene hydrothermal fluids produced an intense phyllic silica–sericite–pyrite zone that was superimposed on the upper parts of the mineralized system associated with the first latite porphyry pulse to develop a higher grade zone of copper–molybdenum ore with grades of >0.4% Cu as chalcopyrite and molybdenite. This alteration and mineralization style is principally developed within the Latite Porphyry and the Toquepala Group rhyolites, and only to a minor degree in the underlying andesites.

The Cuajone Operations use conventional truck-and-shovel open pit mining methods.

The open pit mine has a circular conical shape with a diameter of approximately 3.0 km. Currently, the highest elevation of the pit walls is on the southeast wall at 3865 masl. The current bottom of the pit is at 2950 masl, while the depth of the final pit design will be at 2590 masl. Nine pit phases remain in the life-of-mine (LOM) plan, starting with phase 6 and ending with phase 10C.

Pit Design Criteria Summary:
Bench height - 15m;
Minimum mining width - 80m;
Ramp width - 40m;
Ramp gradient - 10%;
Geotechnical berm width - 30-40m;

Mining is conducted using two 12-hr shifts. The mining operations can be summarized as:
• Initial drilling and blasting;
• Loading, using shovels, of the blasted material into haul trucks;
• Transport of ore and waste, depending on destination to WRSFs, run-of-mine (ROM) leach deposit, leach crusher, and mill crusher.

The LOM plan assumes that all sulfide ore material goes directly to the mill crusher and all leachable material goes directly to the leach crusher. The point of transfer from mining to processing is at the point of the conveyors or delivery to the leach pad.

Three pit phases will be operational at any one time, to ensure that production rates can be met. A maximum mining capacity per phase of 80 Mt/a is assumed, with a maximum vertical advance rate of 10 benches per year.

- subscription is required.

The Cuajone heap leach facility was designed to treat oxide ores and produce a copper-rich pregnant leach solution (PLS) that is sent to the Toquepala Operations for solvent extraction/electrowinning (SX/EW) recovery.

The Cuajone concentrator treats sulfide material to produce copper and molybdenum concentrates. Copper concentrates are sent to the Ilo smelter and refinery to produce copper cathodes as the final product. Molybdenum concentrates are bagged and sold as the final product.

Oxide Heap Leaching
Two heap leach facilities, referred to as heap leach facility SX and heap leach facility Phase IV, are used.

Undersize product from the screening stage is then fed to an agglomeration drum. The ore feeding the drum is weighed on the conveyor to calculate the quantities of water and sulfuric acid used in the agglomeration process. The ratio of sulfuric acid added to the drum ranges from 20–25 kg of acid per tonne of ore and the resulting moisture i ........