The Cerro Corona copper-gold deposit is typical of porphyry style mineralisation comprising stock work quartz-pyrite-marcasite-chalcopyrite ± bornite ± hematite ± magnetite veining, hosted by intensely altered intrusive lithologies of diorite to dacitic composition.

The Cerro Corona copper-gold deposit is hosted by a 600 to 700 metre diameter sub-vertical, cylindrical-shaped diorite porphyry emplaced in mid-Cretaceous limestone, marls and siliciclastic rocks. Within the porphyry, the copper-gold mineralisation is primarily associated with zones of stock work quartz veining conforming to classic porphyry-type vein definition. The Cerro Corona porphyry is unusual in that it carries a very high gold content compared to other copper-gold deposits.

There are at least two phases of diorite placement, only one of which is mineralised. The non-mineralised diorite is generally regarded as the last event, and is referred to as ‘barren core’. Most recent geological modelling strongly suggests that the Cerro Corona porphyry probably comprises four or five satellite stocks, the last two of which are barren. Early mineralisation was accompanied by moderate to strong potassic alteration, which has been commonly overprinted by late, semi pervasive argillic alteration and locally, by structurally controlled phyllic alteration assemblages (quartz-sericite-pyrite).

There are three distinct mineralised zones within the deposit. These are identified as the annulus zone, the northern zone and the southern zone. Each of these is treated separately in geological and resource modelling.

In addition to the mineralised zones, the deposit is characterised by several domains conforming to the degree of oxidation and weathering. Supergene oxidation and leaching processes at Cerro Corona have led to the development of a weak to moderate copper enrichment blanket. This allows for the subdivision of the deposit from the surface downward, into an oxide zone, a mixed oxide sulphide zone, a secondary enriched (supergene) sulphide zone and a primary (hypogene) sulphide zone.

Cerro Corona Mine operates one open-pit operation and one copper-gold plant at elevations ranging from approximately 3,600 to 4,000 metres above mean sea level.

The Cerro Corona deposit is mined by conventional surface open-pit mining methods. The final surface mine area is expected to cover some 900 by 1,000 metres. The mining operation will extend from the crest of the original Cerro Corona hill, which peaked at 3,964mRL, to a final depth at around 3,570mRL.

The Cerro Corona pit is mined via open cut methods by conventional drill and blast with a truck and excavator fleet. Load and haul is carried out by 36 tonne dump trucks and excavators with a 9 tonne bucket capacity. Mining benches are all 10m high and haul roads have a maximum gradient of 10%.

All the material requires drill and blast with varying powder factors according to rock hardness, using a 200mm blast hole diameter.[2014 AR p.10]

Accelerated mining based on nine separate pit stages exceeds processing rates allowing tailings generated in the future to be placed back in the pit. Ore is stockpiled during the accelerated mining phase at Cerro Corona and is typically managed at net smelter return (NSR) cut-off values of between US$14.97/t and US$26/t.

The crushing plant comprises two jaw crushers in parallel and two Abon Sizers in each line. Crushed product is conveyed to a two-stage grinding circuit consisting of a Semi Autogenous Grind (SAG) mill and a ball mill, in closed circuit with cyclone cluster for classification. Cyclone overflow represents the final milled product and feeds the flotation plant.

The processing plant reflects a typical copper flotation plant.

The rougher flotation produces a bulk concentrate and final tails, which is then reground and sent to cleaner flotation. The cleaner tails go to scavenger flotation, while the concentrate, with a grade of over 20% copper, goes to the next process.

The final concentrate is thickened and filtered before being stockpiled for road transport (380km) to the Salaverry port, for shipment to copper smelters in Japan, Germany and Bulgaria. The thickened rougher flotation tails and the tails from the cleaner-scavenger flotation are sent by gravity to the TSF.