The Toromocho deposit is located in the core of the Morococha mining district.

The Toromocho copper-polymetallic deposit is a complex, mineralized assemblage of veins, veinlets, stock works, “manto-type” bodies, and disseminated sulfides of the general “porphyry copper” type mineralization hosted in both intrusive and contact metamorphic units with well-zoned mineralization and alteration characteristics in the Morococha mining district. The skarn-type copper-polymetallic mineralized bodies are controlled mostly by the contacts between the Tertiary-age intrusives including diorites, granodiorites, quartz, monzonites, and quartz porphyries and Jurassic-age calcareous host units of the Pucara Formation. Broad areas of the deposit are brecciated with various levels of intensity. The breccia texture crosses all rock types in the central portion of the deposit.

The mineralization of the Toromocho deposit is well zoned. The metal zonation crosses rock type boundaries although the skarn units are better hosts than the intrusive. The deposit shows well developed concentric silicate alteration along with the metal zoning. There is a central potassic zone with secondary biotite, quartz, and pyrite that is surrounded by a phyllic zone with quartz and sericite.

The outer zone is propylitic with epidote, chorite, calcite, and sphene. The wall rocks of the Toromocho deposit include several intrusive phases of the regional plutons, and at least two phases of porphyritic stocks associated with the alteration and mineralization of the Tertiary Toromocho deposit.

The majority of copper mineralization is in the form of chalcopyrite and chalcocite. Molybdenum (moly) and silver are also present as byproduct credits. In the Toromocho deposit, chalcocite is distributed vertically over at least 250m, but some chalcopyrite remains throughout much of this interval. Sequential assays completed by drilling have confirmed this occurrence and provide a sound basis for interpretation of copper mineral species throughout the deposit.

The Toromocho ore body outcrops on the surface at elevations of 4,600m to 4,800m. The copper ore body extends downwards to a flat “bottom” 500m to 600m below the surface. The highest grade part of the ore body lies within a 1.0 km by 2.0 km body of brecciated skarn, surrounding a cupola-like 7-million year old feldspar porphyry and granodioritic intrusive. The ore body contains about 2.5 billion tonnes of plus 0.3% copper resources averaging about 0.5% copper. The primary ore body is over-printed by late-stage, pyritic primary mineralization, clay and serpentine alteration, and supergene chalcocite and covellite enrichment. Spotty and structurally controlled, moderate-to weak, chalcocite enrichment extends from the surface and from the top of dominant sulfides, downward to the bottom of enrichment, 200m to 400m below the present surface. A sulfate zone containing anhydrite disseminations and veinlets occur several hundred meters below the bottom of enrichment.

A significant portion of the original leached capping above the enriched zone was probably stripped by Pleistocene glaciation. The upper half of the enriched zone in many places contains more than 50% leachable copper by sequential analyses. The lower half of the enrichment blanket above the bottom of enrichment and the top of the primary zone is generally only weakly enriched and contains from 15% to 50% leachable copper by sequential analyses.

Metallic minerals in the deposit include chalcopyrite, chalcocite, molybdenite, tetrahedrite, galena, sphalerite, digenite, pyrite, pyrrhotite, magnetite, limonite, malachite, and azurite. Nonmetallic minerals include garnet, diopside, tremolite, epidote, quartz, feldspar, biotite, sericite, chlorite, calcite, anhydrite, chorite, calcite, and sphene.

The Toromocho Mine is a conventional large scale open pit mine. The ore and waste rock is drilled and blasted prior to excavation by electric rope shovel excavators. The ore is loaded into ultra-class diesel powered off-highway rigid dump trucks (Cat’ 797) and hauled to either stockpile, or dumped directly into the primary crusher. The waste rock is hauled to the western waste dump. The mining fleet is owned and operated by Toromocho Mine.

Blast hole drilling operations at Toromocho are conducted using three large electric Pit Viper 351 blast hole drilling rigs. The drills are capable of drilling up to a ± 20 m depth as a single-pass at 350 mm diameter with some 56.7 t of bit loading. All blast holes are loaded with bulk emulsion explosives that are mixed on site by the local explosives contract provider. The blasting contractor supplies all explosives and blasting accessories for each blast. Blasting patterns in the Skarn and Hornfels is on a 6.9 x 8.0 m staggered pattern. The Potassic material is much harder than either the Skarn or Hornfels and achieves optimum fragmentation at a 5 × 6 m staggered pattern.

The main loading fleet at the Toromocho Mine are the three 35 cu.mt rope shovels (Cat’ 4795) supported by a large Le Tourneau 2350 Front End Loader (FEL). The large FEL provides some degree of blending capability and a fall-back loading capacity.

The ore is hauled from the working faces to an ex-pit crushing facility located on the northern side of the pit. Haul trucks dump the high grade ore into one of two rock hoppers which feed the primary crusher. The primary crusher reduces the ore to -150 mm then feeds the broken ore onto a 7 km long overland conveyor belt to the crushed ore stockpile. Ore from the crushed ore stockpile is then fed to the SAG Mill and subsequently to two Ball Mills running in parallel.

The Group plans to employ a semi-autogenous grinding mill/ball mill/flotation processing plant that is standard for the industry, with a designed average daily production capacity of 1,838 tonnes of 26.5% copper concentrates over the 36-year life of the mill and a separate molybdenum hydrometallurgical plant with a designed average daily production capacity of 25.1 tonnes of molybdenum per day over the life of the mill. Based on the planned production capacities described above, the Toromocho Project has an estimated mine life of 32 years and an estimated production life of 36 years.

The second-phase expansion work at the Toromocho mine to expand the copper concentrate processing capacity was started in June 2018. The Toromocho expansion aims to increase copper production by 45%, increasing its capacity to 300,000 tonnes a year of fine copper in concentrates. The expansion will increase its processing capacity to 170,000 tonnes a day from its current 140,640tpd.