Optimised plant design should consider each element within the process flow. Global best practice emphasises the incorporation of transfer chutes that have been designed and engineered to suit the specific application. A product of intensive research and development, Weba Chute Systems can play a critical role in the mineral processing industry.

Many project houses in South Africa typically view transfer chutes as a poor cousin to other capital-intensive items in the plant. In addition, there is an erroneous belief that mines can reduce costs by installing a cheaply fabricated chute. Ironically, these poorly constructed chutes incur unnecessary costs for the customer.

The uncontrolled discharge of bulk materials through conventional chutes is associated with escalated maintenance and replacement costs. Given the nature of their application, the design and engineering of the transfer points should be carefully considered, as they can easily become the obstacle to efficient operation.

It is now accepted by the global mining community that poor design and implementation of transfer points can result in increased maintenance costs for minerals processing systems. This fact belies the belief that chutes are just fabricated platework.

By adopting a streamlined and scientific approach to the dynamics of bulk materials handling at transfer points, Weba Chute Systems are able to provide the industry with a multitude of benefits. If due consideration is given to customisation at the design phase, these benefits include reduced maintenance requirements, improved transfer conditions, longer conveyor belt life and higher throughput.

Controlling the transfer of material onto the conveyor belt eliminates a high proportion of wear and tear and minimises the rebound that traditionally sends clouds of dust into the air. This ensures not only increased cost saving advantages for customers, but also boosts occupational health and safety compliance.

Extensive experience in the field and input from a knowledgeable team of engineers has resulted in the evolution of Weba Chute Systems. Each project is approached on an individual basis, with engineers adopting a hands-on approach. Liaison with customers during on-site visits allows the Weba Chute System team to devise tailor made solutions that provide a high-level return on investment.

By considering the idiosyncrasies and needs of each transfer point on a plant, these chutes become a major part of the plant, much in the way that a screen, grizzly or feeder is considered an essential process item.

Mark Baller, managing director of Weba Chute Systems, cautions against the selection of cheap, off-the-shelf transfer chutes. "We have experienced many instances where a sub-standard chute has become a liability in a plant. Sadly, the short-term capex savings afforded by these products is counteracted by the negative effects on the long-term operational costs.

"Unfortunately, when these systems fail we are forced to go in after the fact and redesign and re-engineer the chutework. We find on many occasions that the transfer station has not been correctly configured. The difficulty arises where we are unable to implement the most appropriate solution due to the limitations of the existing transfer station. If the system had been carefully designed and engineered from the outset, then these issues would not arise," adds Baller.

Baller is of the opinion that practical experience and inherent knowledge cannot be bought. "In addition, irrespective of how sophisticated a computer programme is, it is not a substitute for the applied expertise gained by refining engineering processes in a host of applications throughout the world. Furthermore, the outcome of any computerised engineering effort is solely reliant on the input. Therefore, we revert once again to the intellectual property of the engineering team."

Baller explains that his team utilises Discrete Element Method (DEM) simulation as a verification tool only. We are adamant that the design ideas and concepts should be derived from the IP that exists in our engineering team. By complementing our own sound engineering tools and substantial practical knowledge with DEM, we are able to provide customers with a high-end chute solution.

"It is important that project houses and mineral processing companies consider the implications that inferior transfer chutes can have for the entire plant. The long term costs that result from this thrifty approach to plant design include the extensive maintenance and modification of chutes as the best case scenario, or the complete replacement of chutes as the worst case scenario. In both instances, the associated downtime and loss of income are clearly not conducive to good business practice," adds Baller.

"I would like to emphasise that we are not competing with the project houses. It is not a draughtsman’s job to design chutes. These products require custom engineering to ensure that the transfer point solution precisely meets the specific parameters within a given application. The end result is improved material flow, reduced maintenance and a satisfied customer," Baller concludes.