ABB (Zurich, Switzerland), working with TAKRAF, has completed commissioning and testing for the world’s highest-powered gearless conveyor drive system, enabling continuous operations at Chuquicamata copper mine in Chile
ABB has provided engineering design, gearless conveyor drives, electrical equipment for power supply, energy distribution and automation of a new underground and overland conveyor system at the world’s largest open-pit copper mine.
ABB has completed commissioning of what is said to be the world’s most powerful conveyor system (Source: ABB)
Project management and engineering for the full electrical, control and instrumentation (EC&I) scope was led by ABB in Germany, with long spells on site in northern Chile to work side-by-side with TAKRAF to equip the site’s new underground operation with a large conveying system that overcomes an altitude difference of 1,200m and covers a distance of almost 13km.
The three principal 11,000-ton/h conveyors feature gearless conveyor drives (GCDs) equipped with large ABB AC synchronous motors with a rated power of 5MW each, resulting in a motor shaft torque of about 900kNm. With every line in constant use, high availability and low maintenance are essential. Designed with a minimum of transfer stations, just one was required underground, saving a significant project cost.
Based on continuous conveying technology, the infrastructure is completely truckless, eliminating the need for 120 large haul trucks. This results in saving around 130 million liters of gasoline consumption per year, bringing the carbon emissions from 340,000 ton/yr down to 100,000 ton/yr. It is also the first transportation system in the world to employ premium steel cable belt technology, ST10000, for use on uphill tunnel conveyors.
“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 only providers capable of delivering a mega project of this nature incorporating advanced technologies that push the boundaries of what has been done before. This is a complex project of the highest magnitude demanding global cooperation between internal and external parties.”
“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 aquisition, equipment assessment and process optimization.” 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 liquid-cooled MV voltage-source frequency converters, together with large synchronous motors, deliver a decrease in active and reactive power consumption. This is highly energy efficient, and without additional network filters.
ABB’s Mining Conveyor Control Program (MCCP) ensures smooth belt operation and safe synchronization between High Power Motors and High Power Hydraulic Brakes, necessary for secure operation of steep uphill conveyors. The drive systems also work without mechanic backstops.
A novel embedding concept, developed jointly by TAKRAF and ABB, enables straightforward installation and alignment of the GCD motors, saving installation time and longer deployment of maintenance teams. This was considered a major benefit compared to existing GCDs in cantilevered construction. The concept also meant motors were 100% factory assembled and tested. They can also be be mechanically disconnected from the drive pulley quickly so operations can continue if drive failure occurs. The total installed drive power for the entire system, including multiple feeder conveyors, totals 58 MW, of which there are 11 x 5 MW gearless synchronous motors.
ABB has also installed ABB Ability Ventilation Optimizer at Chuquicamata reducing carbon emissions and providing clean air to workers in line with the strict HSE requirements.
Commissioning was completed in four months. The new underground project is expected to extend operations at Chuquicamata for the next 40 years.