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

The deposit is ovoid, extending over a 3.3 x 3.5 km area. Mineralization has been drill tested to about 950 m from the original land surface. Drilling from within the pit base indicates primary mineralization extends for an additional 930 m below the pit bottom.

Mineralization is closely associated with a complex, 1,500 m diameter intrusive centre dominated by four phases of porphyritic dacite plugs, referred to as "T", "Main", "L/M" and "Late", a dacite diatreme and agglomerates, extensive hydrothermal breccias and latite porphyry stocks and dikes.

In the mine area, the Toquepala Lineament appears to control some aspects of mineralization. The lineament is based on the distribution of three porphyry stocks, two breccia bodies, numerous pebble and thin intrusive dikes within the mine, as well as the Cerro Toquepala, Cerro Azul and Totoral breccia pipes, along a 20º azimuth. The lineament is controlled by a north–northeast-trending pre-mineral fault system.

Mineralization consisted of leached capping, oxide, enriched, transitional and primary mineralization. The first three types have largely been mined out.

Mineralization types included:
• Leached capping was predominantly limonite (jarosite 30%, hematite 60% and goethite 10%) mostly disseminated and in fractures. It is mostly mined out; however, remnants occur around the periphery of the pit.
• Oxide mineralization was very sparse and may be entirely mined out.
• Enriched mineralization consisted of 90% chalcocite, and 10% digenite, covellite, and bornite in breccia matrix, disseminations, and veinlets. This material had the highest copper grades and is mostly mined out.
• Transition mineralization was about 60% chalcopyrite, 25% chalcocite and 15% molybdenite and bornite as breccia matrix, disseminations, and veins associated with quartz. It is mostly mined out, but remnants are localized on the west edge of the pit.
• Primary copper mineralization occurs as hypogene sulfides mainly restricted to the dacite porphyry and breccias. Chalcopyrite is the dominant economic mineral (90% of mineralization) with 10% bornite, molybdenite, and enargite as dissemination fracture fillings, and breccia matrix. It is associated with potassic alteration (biotite and/or K-feldspar) with about 1% of pyrite (pyrite to chalcopyrite ratio of about 3:1) associated with magnetite and anhydrite. Economic molybdenite mineralization is associated with quartz veinlets and locally, with disseminated chalcopyrite.

In the phyllic zone, pyrite is present as 10% of the rock. The pyrite to chalcopyrite ratio is about 12:1, associated with minor molybdenite, bornite, chalcocite, sphalerite, and galena.

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

The open pit mine currently has a circular, conical shape with a diameter of approximately 3.1 km. At present, the highest elevation of the pit walls is on the east wall at 3665 masl. The current bottom of the pit is at 2725 masl, while the depth of the final pit design will be at 2095 masl. Eight pit phases remain in the life-of-mine (LOM) plan, starting with phase 4 and ending with phase 11.

Pit Design Criteria:
Bench height - 15m;
Minimum mining width - 100m;
Ramp width - 37.5m;
Ramp gradient - 8%;
Inter-ramp height - 150m;
Geotechnical berm width - 20m;
Bench face angle - 65 degree;

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.

Toquepala Concentrator No. 1
ROM material is received from the open pit by truck and unloaded onto two primary gyratory crushers (60 x 113 inch) located to the north of the open pit. Crushed material (nominal 80% passing size (P80) of 140 mm) is then collected in a discharge box at the bottom of the crusher. An arrangement of two conveyors transports the crushed material for approximately 2,200 m to temporary storage in coarse ore stockpile No.1 with a capacity of 141,000 t.

Four apron feeders reclaim ore from beneath coarse ore stockpile No.1, and the ore is transported to coarse ore stockpile No.2 with a capacity of 60,000 t. Ore from stockpile No.2 is delivered to three double-deck vibrating screens (two that are 7 x 14 ft and one that is 8 ft x 14 ft) via belt feeders.

The oversize material feeds three MP-800 secondary cone crushers to generate a particle size product of minus 38 mm. Undersize material from the screens and the product of the crushers is then screened in six tertiary screens. The coarse fraction from the tertiary screens is crushed in six conical tertiary crushers. The product from the crushers and the fine product from the tertiary screens are then transported to a HPGR surge bin. The feed to the HPGR has a particle size average of 12–14 mm.

Fine material from the high pressure grinding roll (HPGR) surge bin unloads onto a 2.4 x 1.65 m HPGR with an installed power of 5.3 MW. The HPGR product is conveyed to a fines hopper of 25,000 t of capacity. The HPGR produces material in the range of 8–10 mm.

Grinding is performed in two parallel lines. The first line uses eight rod mills rated at 746 kW as the primary grinding stage, and 24 ball mills rated at 597 kW each as the secondary grinding stage. The second line uses a single stage 21 x 33.5 ft ball mill with an installed power of 7,085 kW working in closed circuit with cyclones. Product slurry from both lines is monitored by particle size analyzers and fed to the flotation stage with an average particle size of 200 µm.

Toquepala Concentrator No. 2
The C1 primary crushing circuit is shared with C2. From coarse ore stockpile No.1 the material is fed to the C2 secondary crushing circuit with a nominal 80% passing size (P80) of 140 mm.

Four apron feeders reclaim ore from beneath coarse ore stockpile No.1 and transfer it to a secondary crushing surge bin of 1,648 t of capacity. Two apron feeders under the surge bin deliver ore to two double-deck banana screens of 3.4 x 7.6 m. The oversize feeds two MP1250 secondary crushers producing a P80 product of 50 mm. Undersize material from the screens and the product of the crushers are transferred to the tertiary crushing stage.

The product from the previous crushing stage is temporarily stored in a HPGR surge bin before being fed to two 2.4 x 1.65 m HPGRs. Each HPGR has an installed power of 5,300 kW and operates in closed circuit with four wet screens. Product from the HPGRs (-18 mm) is transferred to four double-deck vibrating screens (3.7 x 8.5 m) through a surge bin. The ore is wet classified, producing an undersize fine slurry that becomes the feed to the grinding circuit, and a coarse washed oversize material that is recirculated to the HPGR surge bin.

Grinding is done in two parallel lines where each line consists of a cyclone feed pumpbox, a cyclone cluster (12 x 33 inches), and a gearless ball mill (7.6 x 12.4 m effective grinding length) rated at 15 MW. The cyclone pumpbox receives the product slurry from the HPGR wet screening at 31% solids and the ball mill product at 72% solids. Water is added to the pumpbox to control the solids content before the slurry is pumped to the cyclone cluster at 55% solids. Cyclone overflow slurry at a P80 of 180 µm is the flotation circuit feed, whereas cyclone underflow is gravity fed to the ball mills. Operating in closed circuit with the cyclones, the ball mill product is discharged to the cyclone pumpbox at a circulating load rate of 350%.

The Toquepala LESDE plant was designed to treat low-grade sulfides from the Toquepala mine which are uneconomical to be treated in the concentrators. The material is deposited in dumps and a portion of the contained copper is recovered by conventional dump leaching, and SX/EW.

Toquepala Concentrators No.1 (C1) and No. 2 (C2) are designed to treat sulfide material and produce copper and molybdenum concentrates.

The copper concentrates produced are treated at the Ilo smelter and refinery to produce copper cathodes as the final product.

Heap Leach and Solvent Extraction–Electrowinning Circuit
Copper is recovered from two sources:
• Loaded pregnant leach solution (PLS) coming from the oxide leaching plant located at the Cuajone mine, approximately 30 km north of Toquepala.
• Low-grade heap leach dumps at the Toquepala mine.

The heaps are situated to the south and northwest of the Toquepala open pit, are >100 m in height and have w ........