Antapaccay copper mine is located in the Yauri district of Espinar Province, southern Peru, at 4,100 metres above sea level.
Xstrata acquired the Tintaya open pit mine, comprising of the Antapaccay and the Coroccohuayco deposits, from BHP Billiton in 2006. The Antapaccay deposit is situated approximately 10km from the Tintaya mine.
Commercial copper production at Antapaccay started in November 2012 and the first shipment was made to Matarani Port for export.
Annual copper production from the mine is expected to be 160,000 tonnes in concentrate form. The mine also produces gold and silver by-product credits. The expected mine life is 20 years.
Antapaccay copper mine geology, mineralisation and reserves
“Xstrata acquired the Tintaya open pit mine, comprising of the Antapaccay and the Coroccohuayco deposits, from BHP Billiton.”
The Antapaccay copper mine is a part of the Tintaya district, which is filled with Cretaceous sedimentary rocks and monzonitic plutons. The rocks contain copper bearing minerals, such as the bornite, chalcopyrite, chalcocite and copper oxides.
Antapaccay consists of a sulphide mineralised system with limestone filled rocks containing chalcopyrite and bornite in altered quartz-monzonite and diorite form. The upper part of the deposit is made up of mineralised exoskarn areas, copper carbonates and copper oxides.
Antapaccay’s JORC-compliant ore reserves for the year ending 2011-12 are 541 million tonnes (Mt) at 0.59% copper, 0.13% gold and 1.51% silver.
Mining and ore processing at Antapaccay
The mine consists of two pit operations and a concentrator plant. The concentrator plant, which consists of a semi-autogenous grinding (SAG) mill and two ball mills, can process 70,000 tonnes of copper sulphide ore per day using crushing and rotation.
Concentrate is thickened and filtered at the mine before trucking it to the port for export. Flotation tailings are sent to the tailings thickening plant using the gravity flow.
Siemens’ drive technology at Antapaccay mine
Antapaccay copper mine is equipped with a gearless belt conveyor system featuring Siemens drive system. The system was developed by Siemens in collaboration with the ThyssenKrupp.
“The upper part of the deposit is made up of mineralised exoskarn areas, copper carbonates and copper oxides.”
Antapaccay is only the second mine in the world to be installed with the belt system. The belt is 1,370mm wide and has a conveyor speed of 6.2 metres per second.
The conveyor system includes two slow speed running synchronous motors with a power of 3,800kW. It offers more reliable and efficient operations at reduced costs compared to normal conveyor systems.
The gearless drive system of the 40ft SAG mill has a power rating of 24MW and the two 26ft ball mills have a power rating of 16.4MW each.
Construction and infrastructure facilities at Peru’s mine
The construction of Antapaccay mine created approximately 4,250 jobs. It is also expected to create approximately 1,400 permanent jobs.
Antapaccay will use existing infrastructure at the in-operative Tintaya mine. The shared infrastructure will include the fuel tanks and refuelling system, drinking water supply, office and buildings and mining trucks and shovels. The Tintaya open pit mine will also be used as a tailings storage facility for Antapaccay.
Contractors involved with the Antapaccay mine development
The engineering, procurement, construction and maintenance contract was awarded to Bechtel.
ThyssenKrupp Robins was awarded the contract for supplying the conveyor system. It sub-contracted the same to Siemens.
Siemens was awarded the contract to supply three grinding mills and a gearless belt conveyor system. The supply included entire switchgears and gearless drive system for the SAG and ball mills.
ABB was awarded the contract to supply two synchronous condensers and harmonic filters for the Antapaccay project. It also supplied harmonic filters and controllers, condenser systems, distribution transformers and excitation and protection panels.