MechChem Africa February 2018

The true cost of sub-standard transfer

Mark Baller, managing director of transfer chute experts, Weba Chute Systems, explains the importance of the effect a chute’s performance has on the life of conveyor belts and how the design of such chutes saves costs for customers and complies better with occupational health and safety regulations.

T he level of performance of a mine’s transfer points contributes to some of its highest maintenance costs, but many engineers often do not consider transfer systems as critical elements of the minerals processing systems. This is the view of Mark Baller, managing director of transfer chuteexpert,WebaChute Systems, who believes that transfer points should be accorded the same importance as other minerals processing machinery. The effect of the chute’s performance on the life of conveyor belts – which can account for up

to 60% of the capital cost of a bulk materials handling plant – deserves attention. “The cost of replacing a conveyor belt – not to mention the downtime associated with belt maintenance and replacement – makes it worth looking more closely at any measures that will extend the conveyor’s life,” says Baller. “Typically, conveyors – such as feeders, crushers, hoppers and screens – are selected to match certain operational requirements, but there is little emphasis on the design of the chutes that transfermateri- als between elements.”

This is a mistake, he argues, as chutes are essential elements in a bulk solids handling plant, and are also subject to operational characteristics and physical constraints. “Among the most common problems on transfer chutes are spillage, blockages and high levels of wear on the receiving belt due to major differences between the material velocity and the belt velocity,” he says. “There is also a potential misalignment problem of the receiving conveyor belt –which is caused by uneven loading from the transfer chute.” Key to solving these challenges is good de- sign, Baller emphasises. While conventional chute design often allows the uncontrolled discharge of bulk materials, he considers that a holistic design is necessary – focusing not only on the entry and exit points, but also controlling the flow, volume and velocity of the material being transferred. “Each transfer point therefore needs to be custom-designed, to control the direction, flow and velocity of the material,” he says. “Weba Chute Systems bases its designs on the ‘supertube’ effect, which often employs a cascade lining system – allowing 95% of material to run on other material at all times. Thismay also be achieved using conventional lining systems.” Transfer chute design and end user costs

Weba Chute Systems controls the flow of material onto the belt thereby minimising unnecessary wear.

20 ¦ MechChem Africa • February 2018