Name: Cerro Corona mine.

Location: The Cerro Corona deposit is located 1.5 km west-north-west of Hualgayoc, in Peru.

Mine Owner/s: Gold Fields Corona, a wholly owned subsidiary of Gold Fields, increased its economic interest in Gold Fields La Cima from 80% to 98.6% in 2012, and in 2013 to 99.53%.

Brief Description: Cerro Corona is a gold mine comprising an openpit and a standard sulphide flotation plant.

Brief History: In 1979, exploration identified porphyry‑style mineralisation in the Cerro Corona area. Sampling by the Gubbins Group between 1992 and 1993, identified gold mineralisation in the leached cap of the Cerro Corona deposit.

Copper/gold porphyry mineralisation was discovered through the drilling of nine diamond core holes and completion of an exploration adit into the mineralised zone.

From 1994 to 1996, Cerro Corona, then owned by Barrick, drilled 140 reverse circulation drill holes totalling 9 476 m and 118 diamond core holes totalling 35 254 m. A draft feasibility was completed by Kilborn.

From 1997 to 1998, RGC Limited drilled six diamond core holes totalling 2 760 m and a preliminary feasibility was completed by Fluor. Several feasibility studies were completed in 2001 by Minproc, which ultimately indicated a mineral reserve of about 95-million tonnes.

Gold Fields, through a subsidiary, signed a definitive agreement with Sociedad Minera Corona in 2003 to acquire the Cerro Corona deposit and adjoining mining concessions. The environmental-impact assessment was approved in December 2005 and the purchase transaction for the Cerro Corona project was completed in January 2006. Mine construction started in May 2006.

Construction of the Las Gordas tailings dam and quarrying for the relevant construction material for the project started in 2007. The mine has been in production since 2008 and uses openpit mining and sulphide flotation to produce an auriferous copper concentrate through a flotation circuit.

Primary Metals: Gold and copper.

Secondary Metals: Not stated.

Geology/Mineralisation: The Cerro Corona copper/gold deposit is typical of porphyry‑style mineralisation, comprising stock work quartz/pyrite/marcasite/chalcopyrite, with areas of bornite, hematite and magnetite veining, hosted by intensely altered intrusive lithologies of diorite to dacitic composition.

The deposit encompasses an intrusive diorite to quartz‑diorite dated at mid‑Miocene age. The intrusive is primarily emplaced along subvertical faults. Limestone alteration varies from siliceous in the south of the deposit to marbling in the west.

Reserves: Total gold reserves as at December 31, 2018, were estimated 79.89-million tonnes grading 0.68 g/t gold. Total copper reserves as at December 31, 2018, 79.89-million tonnes grading 0.39%.

Resources: Total gold resources as at December 31, 2018, were estimated at 107.66-million tonnes grading 0.65 g/t gold. Total copper resources as at December 31, 2018, were estimated at 102.66-million tonnes grading 0.37% copper.

Mining Method: The Cerro Corona deposit is mined by conventional surface openpit mining methods.

Major Infrastructure and Equipment: Cerro Corona mine operates an openpit and a copper/gold plant. The processing plant is a typical copper flotation plant, with a design capacity of 6.9-million tonnes a year.

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, comprising a semiautogenous grind 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 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.

Prospects: It is estimated that the current mineral reserve will be depleted only in 2030. Further opportunities are being assessed for a further life-of-mine extension at Cerro Corona.

Contact Details:
Goldfields
Tel +27 11 562 9700
Email  Investors@goldfields.com
Website https://www.goldfields.com