ABB, the leading power and automation technology group, has announced that it has won a follow-up order for the Salobo copper mine project, which is being developed by Salobo Metais SA, a totally owned subsidiary of Vale (former CVRD).

At the end of 2007, ABB signed a contract for the delivery of two gearless mill drive (GMD) systems that will maximise productivity and energy efficiency at the new Salobo copper mine in northern Brazil. Half a year later, in June 2008, ABB was awarded an additional order for the same end user. Polysius, acting as OEM, was awarded the grinding circuit package by Vale and decided to continue with ABB’s experience and expertise in regard to the high pressure grinding rolls (HGPRs).

ABB’s scope of supply for the additional order comprises two MV ACS1000 variable speed drive systems, including motors and transformers, for two High Pressure Grinding Rolls (HPGRs). Each drive system has a power of 2 x 1800kW.

HPGRs are being applied in the mining industry, often as a replacement for the conventional semiautogenous (SAG) grinding mills, primarily to reduce energy consumption and costs within crushing and grinding circuits. They consist of a pair of counter rotating rolls, one fixed and the other one floating.

The feed is introduced to the gap in between the rolls and is crushed. Variable speed drives can adjust the speed of the rotating rolls and thus the throughput of the units which is advantageous for the grinding or crushing of inhomogeneous types of ore. As such, the grinding process can be optimised for ores with varying grinding properties.

The Salobo project is located at the Tapirape-Aquiri National Forest, a municipal district of Maraba, in the state of Para, Brazil. Commissioning of the Salobo copper mine is scheduled for the beginning of 2010.