On Gearless Conveyor Drives (GCDs), ABB has recently supplied large scale GCDs to Codelco's extension of its Chuquicamata copper mine, the Chuquicamata Underground project. Once up and running, this will be the world's largest conveyor system. Such installations of gearless conveyor drives with up to 6 MW single motor power ABB says have shown the promise of increased reliability, improved system efficiencies and reduced maintenance resulting in high profitability and increased safety.
While large conveyor installations as Chuquicamata are stationary, open-pit or IPCC conveyors have to be moveable as they shift with the bank. Such conveyors require a different approach to the gearless drive design.
Ulf Richter, product manager, conveyor systems at ABB Process Industries, Mining stated: "ABB's new GCD for medium power with permanent magnet (PM) motor reduces the drive train's failure rate by 50% and improves energy efficiency. Different mounting variants enable application-optimised use in both, new or retrofit conveyors. A test project established the feasibility of installing GCDs on mobile mining machines and shows the suitability of permanent magnet torque motors to drive conveyors. The results reveal that GCDs are viable alternatives to conventional geared drives. So far, during one year of operation, ABB measured a 6% energy saving and 100% availability of the drive with just two hours inspection."
He adds: "The results from the first project reveal the solution's wide applicability. It is designed to work in all mines. The drive assembly has a relatively compact footprint which is smaller than a conventional gearless system with a synchronous motor. That allows a GCD system with less weight and footprint."
With fewer wear parts, less maintenance is required, and the lifespan is increased. The expected lifespan for the drive train increases by more than 10 years, when compared to traditional geared systems, to a projected in-service life of 25 years. While the upfront investment is typically higher (by as much as 30%) when compared to a conventional drive, the savings in maintenance, energy cost and downtime lead quickly to a return on investment of typically less than one or two years. No additional infrastructure is needed for installation, compared to a conventional gear motor assembly. The GCD reduces the noise emission of the drive drastically so that common noise cancelling housings around the drive are not needed.