Name: Pampa Norte mine.

Location: Pampa Norte is located in the Atacama desert,162 km north-east of Antofagasta, in Chile. 

Controlling Company: BHP Billiton.

Brief History: The mine development was approved in 2004 at a cost of $1.1-billion. First copper was produced in 2006.

Brief Description: The Pampa Norte mine consists of two operations – Spence and Cerro Colorado.

Products: Copper cathode.

Geology/Mineralisation: Both mines feature an enriched and oxidised porphyry copper deposit that presents predominantly in situ copper oxide mineralisation, which overlays a near-horizontal sequence of supergene sulphide, transitional sulphide and lower-most primary (hypogene) sulphide mineralisation.

Reserves: Total proven probable oxide reserves at Spence as at June 30, 2015, 41-million tonnes grading 0.68% of total copper and 0.49% of soluble copper. Total oxide low solubility reserves were 26-million tonnes grading 0.73% of copper and 0.31% of soluble copper. Total supergene sulphide reserves were estimated at 135-million tonnes grading 0.86% of total copper and 0.12% soluble copper. Total run-of-mine reserves were estimated at 55-million tonnes grading 0.37% of total copper and 0.08% of soluble copper.

Total proven and probable oxide reserves at Cerro Colorado as at June 30, 2015, were estimated at 99-million tonnes grading 0.56% of total copper and 0.40% of soluble copper. Total probable sulphide reserves were estimated at 54-million tonnes grading 0.63% copper and 0.12%

Resources: Total oxide resources at Spence as at June 30, 2015, were estimated at 54-million tonnes grading 0.78% of total copper and 0.51% soluble copper. Total low-grade oxide resources were estimated at 81-million tonnes grading 0.22% of total copper. Total supergene sulphide resources were estimated at 179-million tonnes grading 0.80% of total copper. Total sulphide resources were estimated at 26-million tonnes grading 0.71% of total copper. Total hypogene resources were estimated at 2.30-billion grading 0.43% of total copper and 125 parts per million molybdenum.

Total oxide resources at Cerro Colorado as at June 30, 2015, were estimated at 237-million tonnes grading 0.58% total copper and 0.42% soluble copper. Total sulphide resources were estimated at 168-million tonnes grading 0.57% total copper.

Mining Method: Both mines are opencut.

Major Infrastructure and Equipment: The Spence mine comprises processing and crushing facilities, separate dynamic (on-off) leach pads, a solvent extraction plant and an electrowinning plant. The nominal capacity of the tank house is estimated at 179 000 t/y of copper cathode.

The Cerro Colorado mine has two primary, secondary and tertiary crushers, leaching pads, a solvent extraction and an electrowinning plant.

The nominal capacity of the tank house is estimated at 102 000 t/y of copper cathode.

Prospects: The Spence Growth Option (SGO) project, currently at prefeasibility phase, aims to maximise Spence’s value by exploiting
the large and expandable hypogene resource with associated molybdenum sulphide by building a 95 000 t/d concentrator.

This will increase the mine life by about 50 years beyond the current 2025 financial year closure date. The proposed investment is estimated at $3.2-billion and the project is scheduled to start at the end of the November 2019 quarter.

The hypogene ore underlies the supergene reserves being exploited and, therefore, eliminates the need for prestripping and additional mine maintenance infrastructure. The option to maximise the use of existing heap-leach infrastructure, to recover copper from the lower-grade chalcopyrite ores, is being developed as a complementary process to the concentrator (CPY leach project). The implementation of the SGO and CPY leach projects will enable Spence to achieve a total copper production of about 260 000 t on average during the first ten years of operation.

Contact: Media relations, Ruban Yogarajah.

Contact Details:
BHP BIlliton
Tel +44 207 802 4033
Email Ruban.Yogarajah@bhpbilliton.com
Website http://www.bhpbilliton.com