In a major first for German technology company Siemens, Xstrata Copper has commissioned its Drive Technologies Division to construct a gearless drive system for the belt conveyor and grinding mills at the recently commissioned Antapaccay copper mine in Peru. It will be the first large-scale installation of the technology outside Germany.
Antapaccay mine is 4200 metres above sea level and is scheduled to produce an annual average of 160,000 tonnes of copper in concentrate in the initial years of its more than 20-year projected mine life.
The gearless drives will help to boost the efficiency and reliability of the conveyor system at the mine and reduce maintenance requirements when compared with conventional systems.
Siemens will supply the entire switchgears and gearless drive systems for a 40ft SAG mill and two 26ft ball mills with the associated power supply.
The belt system at Antapaccay was supplied by ThyssenKrupp and transports ore from the mine to the processing plant over a distance of about 6.5km. It has a belt width of 1370 millimeters and a conveyor speed of 6.2 metres per second, transporting 5260 tonnes of ore in an hour.
The Siemens drive system for the belt conveyor consists of two slow speed running synchronous motors, each with a power rating of 3800 kilowatts, and the associated cycloconverters Sinamics SL150 and convertor transformers.
Siemens’ drive technologies chief executive officer Ralf-Michael Franke says when compared with the combination of high-speed motor and gear units otherwise used in belt conveyor systems, the gearless drive solution offers a range of benefits. “The size of the motor is not limited by the size of gearbox available, thus eliminating the necessity to install multi-motor drives. The required belt driving power can be provided with one drive per drive pulley, meaning that the number of switchgear enclosure could also be scaled down, saving space and weight.”
By eliminating a whole series of mechanical and electrical components, the reliability and efficiency of the overall system is increased while the maintenance requirements of the drive system are significantly reduced.
Siemens will also supply the high-voltage and gas-insulated medium-voltage switchgear for the main distribution, as well as the low-voltage switchgear for the overall plant. This equipment enables safe and reliable power distribution under the typical harsh environmental conditions in high altitude mountainous regions.
Australian-based Xstrata Copper is the fourth largest copper producer in the world. It began producing copper at Antapaccay late last year, previously awarding Siemens the conveyor belt project and the contract to supply the electrical equipment for the grinding mills.