ABB, working with TAKRAF, has completed commissioning and testing of the world’s highest-powered gearless conveyor drive system at the Codelco-owned Chuquicamata copper mine in Chile.
ABB has provided engineering design, gearless conveyor drives (GCD), electrical equipment for power supply, energy distribution and automation of a new underground and overland conveyor system at one of the world’s largest copper mines.
Chuquicamata is currently transitioning from open-pit to underground mining, with the conveyor system, commissioned in just four months, part of a new underground project that is expected to extend operations for the next 40 years.
Project management and engineering for the full electrical, control and instrumentation 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 1,200 m and covers a distance of almost 13 km, ABB said.
The three principle 11,000 t/h conveyors feature GCDs equipped with large ABB AC synchronous motors with a rated power of 5 MW each, resulting in a motor shaft torque of about 900 kNm. 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 significant project cost, ABB said.
Based on continuous conveying technology, the infrastructure is completely truck-less, eliminating the need for 120 large haul trucks. This results in saving around 130 million litres/y of gasoline consumption, bringing the carbon emissions from 340,000 t/y down to 100,000 t/y. It is also the first transportation system in the world to employ premium steel cable belt technology, ST10000, for use on uphill tunnel conveyors, according to ABB.
“This mega project achieves a number of firsts, from the system’s installed drive power to the application of the ST10000 conveyor belt,” Marc Hollinger, TAKRAF Project Manager, said. “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.”
Ulf Richter, Global Product Manager for Belt Conveyor Systems at ABB, said: “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.
“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 at the operation. This is highly energy efficient, and without additional network filters, it says.
ABB’s Mining Conveyor Control Program ensures smooth belt operation and safe synchronisation 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, ABB said.
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 with existing GCDs in cantilevered construction, ABB said. The concept also meant motors were 100% factory assembled and tested. They can also 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 health, safety and environment requirements.