Cerro Verde Copper-Molybdenum Mine

Cerro Verde Copper Mine is an open-pit copper and molybdenum mining complex located 32km south-west of Arequipa in Peru.

The mining concession spreads across approximately 157,007 acres (63,538ha), plus 24 acres of owned property and 79 acres of rights-of-way outside the concession region. It is the second biggest copper mine in Peru, based on contained reserves.

Freeport MacMoRan, through its subsidiary Cyprus Climax Metals, owns 53.56% stake in the mine and SMM Cerro Verde Netherlands, a subsidiary of Sumitomo Metal Mining, holds 21%, while Compania de Minas Buenaventura and others have 19.58% and 5.86% stake respectively.

Cerro Verde has been in operation since 1976, and became part of Freeport-McMoRan’s mining portfolio in 2007.
Freeport-McMoRan Copper & Gold, which operates the mine, announced plans in 2011 to triple the treatment capacity at Cerro Verde. The company received important permits for the proposed expansion and commenced construction in 2013.

A copper sale agreement has been signed with Sumitomo Metal Mining and a molybdenum sale contract with Climax Molibdenum Marketing.

Production at the Peruvian copper-molybdenum mine

Cerro Verde produced 121.7 million pounds of copper in the first quarter of 2013 whereas 269,649t of copper and 3,982t of molybdenum were produced in 2012.

Details of the Cerro Verde mine expansion

The $4bn project aiming to triple the sulphide ore extraction and processing capacity is expected to place the Cerro Verde mine among the top five global copper producers. Sumitomo decided to approve the implementation of the expansion project in February 2014.

The proposed large-scale expansion aims at improving the concentrator units from 120,000t per day (tpd) to 360,000tpd and providing incremental annual production of approximately 600 million pounds of copper and 15 million pounds of molybdenum from 2016.

History of the Peruvian mine

Spain used to mine high-grade copper oxide ore from Cerro Verde and ship it to Wales in the mid-1800s. In 1970 the Peruvian Government acquired the Cerro Verde mine from Anaconda, which had owned the property since 1916, and mined oxide ores and built one of the world’s first solution extraction/electrowinning (SX/EW) plants in 1972.

Cyprus Amax purchased the operation in 1994, investing in the property to upgrade and improve production at the mine.

Copper production at Cerro Verde increased by about 350% while operation costs reduced by more than 40% following the mine’s privatisation in November 1993.

Cerro Verde mine geology, mineralisation and reserves

The Cerro Verde mine includes three concessions namely Cerro Verde 1, 2 and 3, consisting of approximately 20,825ha, which include Santa Rosa, Cerro Verde and Cerro Negro deposits.

Brochantite, chrysocolla, malachite and copper pitch are the major oxide copper minerals at the mine. The main primary copper sulphide minerals include chalcopyrite and molybdenite, while the most important secondary copper sulphides include chalcocite and covellite.

The mine is estimated to contain sulphide ore reserves of 25 billion pounds, whereas leach ore reserves are estimated to be 1.6 billion pounds of copper. The recoverable copper reserve at the end of 2012 was estimated at 12.9mt.

Mining, processing and associated facilities at Cerro Vserde

The orebody of the Cerro Verde open pit is accessed through three vertical shafts and a decline. The mine features a 120,000t/d concentrator and solution extraction/electrowinning leaching plants, and produces over 200 million pounds of copper per year through leaching operation.

The 39,000tpd crushed ore leach facility and a run-of-mine (ROM) leach system are used for leach-copper production. The mine also includes equipment such as crusher/conveyor, agglomerating facility and stacker/conveyor system.

A new 119,000tpd concentrator was installed in late 2006 and the mill achieved its design capacity of 108,000tpd in June 2007.

The mine moves an average of 300,000t of material per day using 200t and 255t haul trucks loaded by shovels with bucket sizes ranging from 28 to 60 cubic yards. The copper cathodes and concentrate are transported to the Pacific Port of Matarani for shipment to overseas.

Contractors and suppliers involved

Freeport-McMoRan Copper & Gold contracted Fluor Corporation to provide construction management services for the expansion of the mine in mid-2013.

The contract involves provision of construction management services for the new 240,000tpd concentrator and associated infrastructure including a new 220kV transmission line, a new wastewater treatment plant for the city of Arequipa, upgraded fresh water pumping system, new tailing storage facility, and ancillary buildings and facilities.

ABB was contracted to supply gearless mill drives (GMDs) for six ball mills and twin-drive systems for eight high-pressure grinding rolls (HPGRs) in March 2012 for the concentrator expansion.

Cerro Verde has entered into long-term contracts with Electroperu and EGASA for the supply of electrical power.