The 58 MegaWatt drive power system has been designed to overcome an altitude difference of 1,200m, and cover a distance of almost 13km, to ensure continuous operations at Chuquicamata.

The gearless conveyor drive (GCD) system has three principal 11,000t/hr conveyors equipped with 11 ABB AC synchronous motors, with a rated power of 5MW each, resulting in a motor shaft torque of about 900kNm, said the companies.

The belt system delivers copper ore from the underground mine directly to the concentrator plant, removing the need for 120 large haul trucks and 130 million litres of gasoline. It therefore achieves a 70% saving in carbon emissions - from 340,000 t/yr down to 100,000 t/yr, said ABB.

"This is a new milestone in underground applications for continuous mining. It is the highest drive power ever installed on a conveyor and uses a wide range of features for data acquisition, equipment assessment and process optimisation," said Ulf Richter, global product manager for Belt Conveyor Systems at ABB.

"In piloting this gearless drive application with TAKRAF we have overcome tremendous technical and logistical challenges due to underground situations, elevation change and capacity requirements."

ABB provided the engineering design, GCDs, electrical equipment for power supply, as well as the energy distribution and automation of the new underground and overland conveyor system.

The project is the first transportation system in the world to employ premium steel cable belt technology, ST10000, for use on uphill tunnel conveyors.

It also uses a novel embedding concept, developed jointly by TAKRAF and ABB, that enables easier installation and alignment of the GCD motors. ABB also used liquid-cooled MV voltage-source frequency converters, together with large synchronous motors, to deliver a decrease in active and reactive power consumption.

"This mega project achieves a number of firsts, from the system's installed drive power to the application of the ST10000 conveyor belt," said Marc Hollinger, TAKRAF project manager. "With this project, we firmly establish TAKRAF as one of the world's few providers capable of delivering a mega project of this nature."

The commissioning was completed in four months, and the the new underground project enabled by the system is expected to extend operations at Chuquicamata for the next 40 years.