ABB has commissioned an upgrade to Vale’s existing Clarabelle dual pinion semi-autogenous (SAG) mill (Fig. 1). The mill is used to reduce the size of the ore at the company’s nickel and copper mines in the Sudbury area, Ontario. The project was completed on-time and on-budget with an excellent safety record. Located in Ontario about 400 km north of Toronto, Vale’s Sudbury operations are primarily underground nickel sulphide mines with integrated mining, milling, smelting and refining operations. One of the characteristics of Clarabelle Mill is to accept nickel-copper ore from various sources and companies and to produce a nickel-copper concentrate and copper concentrate for further processing. The size of the ore is further reduced in semi-autogenous mills, rod mills and ball mills where all milling is done wet (Fig. 2).
First awarded in 2010, the project is the largest of several turnkey projects completed for Vale in Canada. This complex project involved upgrade to a SAG mill of 10 m diameter, and 11.2 rpm that had reached end-of-life with a newer, more robust system. ABB replaced all of the electrical equipment including 5500 KW motors, converter, transformer, motor control centers, switchgear and mechanical auxiliary equipment such as the cooling system. The company also modified the existing foundation and air clutch coupling to adapt it to the new motors. A number of SAG mill applications were implemented to facilitate the operation and maintenance of the SAG mill. ABB also built an additional structure next to the existing mill to house all the new equipment and integrate its system with the mill. Engineering and construction of the building extension included excavation, foundation, civil, structural steel and architectural works as well as insulation, fire system, lighting, heating, ventilation and air conditioning.