ABB has successfully installed and commissioned the first gearless mill drive (GMD) system for Codelco at the Andina mine in Chile. Bechtel in Santiago, Chile, acted as EPCM contractor for the project and Metso Corp was the mill supplier.The scope of supply consisted of a 13,050kW gearless drive motor including preassembled, containerised electrical house containing cycloconverter, exciter rectifier, low voltage MCC, as well as all the auxiliary equipment to operate the gearless drive motor system and the mill auxiliary equipment.

Andina is located 3,700 to 4,200m above sea level with the crushing, grinding and flotation lines located in an underground concentrator. The main challenges related to the underground location, in that the 7.62m x 11.23m stator had to fit a tunnel of 6m x 6m and the bridge crane capacity was 60t only.

ABB’s solution consisted of the first stator being split into five sections to deal with the logistical challenges of the location, while maintaining the usual stability of the system. The design typically consists of four segments, but the demands of this project challenged ABB to divide it into five parts.