ABB was recently contracted to supply gearless mill drives (GMDs) for six ball mills and twin-drive systems for eight high pressure grinding rolls (HPGRs) at Cerro Verde copper mine in Peru. The two contracts were awarded in the first quarter of 2012. Deliveries are scheduled for Q4 2013 and Q1 2014. ABB’s scope of supply includes six 22 MW GMD systems for 27 ft diameter ball mills comprising of transformers, ring motors and complete containerised electrical houses as well as eight 2 x 2,500 kW twin-drive systems for HPGRs that include squirrel cage induction motors, transformers and ACS1000 frequency converters.

The statement said: “Known as the most efficient systems for grinding mills, ABB’s powerful, state-of-the-art GMDs help mine operators improve overall productivity while providing reliable equipment performance and flexibility.” Each of the six GMDs will be equipped with two of ABB’s rotating air gap sensors, which together with the 12 standard air gap sensors on the stator will give a true 360 degree overview of the stator and rotor. The HPGR drive systems work in accordance with the high demanding requirements for such machines without using tachometers or encoders. ABB had already supplied mine electrification and various drive systems, also including GMDs and HPGR drives, for the previous greenfield Cerro Verde project in 2006.