The overland conveyor in Xstrata's Antapaccay copper mine will transport ore over a distance of some 6.5 kilometers from the mine to the processing plant. The belt will be 1,372 millimeters wide, travel at 6.2 meters per second, and is designed to transport approximately 5,260 tons of material per hour. The Siemens drive system for the overland conveyor comprises of two slow- speed synchronous motors – each with a total power of 3,800 kilowatts – and the associated Sinamics SL150 cycloconverters. Each motor is connected directly to the drive pulley.

This gearless drive solution has a number of advantages over the combination of high speed motor and gearbox usually used on conveyor systems. The size of the motor is not limited by the size of gearbox available, thus eliminating the necessity to install multi-motor drives. The power required to drive a belt can be provided by just one drive per belt pulley. This enables the size of the electrical room to be reduced, saving space and weight.

The elimination of a whole series of mechanical and electrical components increases the reliability and efficiency of the overall system by between three and four percent. The maintenance requirements of the drive system are also substantially lower. Gearbox maintenance work alone can amount to up to five percent of the original investment volume – each year. Lubrication and gearbox cooling systems, together with their maintenance, are also obsoleted for this solution.

The gearless drive system for the Overland Conveyor System in the Antapaccay mine is the second of its type. The first conveyor system to run with gearless drives was installed in 1986 by ThyssenKrupp (formerly O&K) and Siemens in the Prosper-Haniel Mine belonging to Deutsche Steinkohle AG, and it achieves an availability of over 98 percent.

Xstrata Copper, based in Brisbane, Australia, is part of Xstrata plc, and operates mines and production plants in Argentina, Australia, Chile, Canada and Peru. The company is the fourth largest copper producer in the world, and has a production capacity of almost one million tons per annum. The Antapaccay copper mine in the south of Peru is Xstrata's latest project. As from 2012, it is scheduled to produce some 160,000 tons of copper concentrate per annum.

ThyssenKrupp Robins is the US subsidiary of ThyssenKrupp Fördertechnik. The company spezializes in the design and supply of technologically advanced conveyor applications.