The world record setting Metso's MRC Cable Belt is a unique conveyor design that is ideally suited for long distance conveyor applications where vertical and horizontal curves are required. The ability to negotiate low radius curves by this conveyor can significantly reduce the costs of installation and civil works that are a major feature of large conveyor systems. In addition, routes that would commonly be achieved by multiple conventional conveyors can often be done by a single flight Metso's MRC conveyor and the need for multiple transfers is eliminated, reducing material degradation, transfer maintenance and often the total installed system power.
To the left, a Cable Belt conveyor is featured that runs across and through the hills and valleys of the Appalachian Mountains in West Virginia. This conveyor carries coal from the mine to a train load-out facility. The total conveyor length is roughly 6.4km with an overall lift of 160 meters.
The design of Metso's MRC conveyor differs to that of conventional conveyor designs. The conveyor belt is supported by two endless wire rope cables, one on each side of the belt, in lieu of idlers. The belt has almost no tension induced as it simply “goes along for the ride”. This type of design requires a special sort of belting and Metso manufactures a belt known as PVL, or ‘pre-formed for variable loading’. The belt is designed to be pre-formed or “dished” to maximize the amount of material that can be carried while minimizing material spillage. The belt is more rigid across the width than a conventional conveyor belt as it must support both its own weight and the material load. Additionally, the belt is designed to deflect a specific amount under load according to the capacity and characteristics of the material to be carried.
Cross section of MRC curved conveyor.
The drive cables not only support the belt but also provide the driving mechanism for the conveyor. The ropes support both the carry and return sides of the belt. The ropes and belt are separated at the discharge and tail/loading ends where they each wrap around their respective return pulleys or drums. As the rope is the driven component, it wraps around a friction drive wheel that can be snubbed or non-snubbed. Drive area location can vary in position as the conveyor profile dictates. Likewise, the rope and belt tension areas vary in location along the conveyor’s length as the design requires and multiple drive units can be used to minimize the peak tensions induced into the rope, thus minimizing the rope size and other system components.
As with conventional conveyors, DC or AC variable speed drives can be offered, while standard reducers, couplings and braking systems are used to drive and control the conveyor. The major difference between the drive of a Metso MRC conveyor and a conventional, is that with an MRC conveyor, two drives are required, one for each rope. An electronic differential is used to balance the load and speed on each drive and this same technology allows for the simple introduction of the multiple drives.
For long-distance material handling, Metso's MRC Cable Belt conveyor provides for a reliable, well proven means for transport over the most rugged and arduous terrain. The conveyor is well suited for use as a slope belt, overland conveyor or down hill system. Over the years, Cable Belt conveyors have seen work in a variety of environments, from the frigid temperatures of North Dakota and British Columbia to the tropical climates of Jamaica and South America. Whether underground in Canada or the United Kingdom, or overland in Australia or the Philippines, the Metso MRC conveyor can be tailored to meets the needs of the project.
Cable Belt stocked parts