Minera Chinalco Perú S.A., a subsidiary of Aluminium Corporation of China has placed an order with the Siemens Drive Technologies Division for an integrated drive system for two new mills at the Toromocho mine in the Peruvian province of Yauli.
Two gearless mill drives and Sinamics cycloconverters will be used in the new production line with one SAG mill and one ball mill, enabling one million tons of copper concentrate, 10,000 tons of molybdenum and four million ounces of silver oxide to be mined annually even at an altitude of around 4,600 metres above mean sea level.
The Toromocho mine in Morococha, Yauli province, Peru is situated less than 150km from the capital city of Lima. Since the mining area for copper, molybdenum and silver is around 4,600 metres above mean sea level, special requirements apply to the mill drives. Not only must they be able to cope with the rugged environment in a mine, they must also fulfil the special requirements of the remote mine site topography.
Siemens will be delivering two gearless mill drives and water-cooled Sinamics SL150 cycloconverters to meet these special Toromocho requirements. In future, the 36-foot SAG mill of the new production line will be operated with a 13.5-megawatt drive. Another gearless mill drive with 22 megawatt output will ensure equally efficient and reliable driving of a ball mill with an inner diameter of 28 feet.
Gearless drive systems are distinguished by their high efficiency and low maintenance effort. Complex maintenance operations at an altitude of 4,600 metres can thus be avoided, which saves time and cost for the operator. The Sinamics cycloconverters are characterised by low switching losses due to their thyristor technology and also contribute to high efficiency. The drive components help achieve a high availability of more than 99 per cent.