Weba Chute Systems has installed more than 300 transfer points at various sections of Assmang’s iron ore mine in South Africa’s Northern Cape and the most recent 19 chutes are poised for hot commissioning as part of the WHIMS Expansion Project by the end of February 2013. Assmang Ltd, which is jointly owned and controlled by African Rainbow Minerals and mining holding company Assore, initiated the KEP to increase the Khumani mine’s capacity from 10 Mt/y to 16 Mt/y. The Weba Chute Systems order forms part of the greater Khumani Wet High Intensity Magnetic Separation (WHIMS) Project (KWP) that will incorporate a new WHIMS super fines beneficiation circuit and related infrastructure into the existing Parsons processing plant.
The Weba Chute team was tasked with engineering chutes capable of reducing production losses related to blockages, eliminating spillage and achieving an 80% maintenance-free transfer point. “The major application requirement on the latest Expansion Project (WHIMS) was to cater for the extreme stickiness of the material, which is prone to choking and blocking in transfer points,” Weba Chute Systems’ Managing Director, Mark Baller, says. “Although we have extensive experience with the type of material being handled at this operation, the application in itself presented certain challenges owing to the super fines being transferred from conveyor to conveyor. These particle sizes range downwards from 2 mm to micron proportions and the material is very abrasive and sticky. Our design has, therefore, incorporated 20 mm high alumina ceramic engineered tiles to facilitate the necessary level of abrasion resistance and the free flow of the sticky material.”
Baller adds that one of the primary objectives during the design phase was to ensure that the angle of flow within the chute was such that it would not choke or block during material transfer. In total, 19 chutes were custom designed, each ceramic lined and taking specific installation and application factors into account. The tonnage throughput rate varies from 120 t/h to 900 t/h, feeding onto the receiving conveyor. Conveyor widths vary from 750 mm to 900 mm, with belt speeds between 2.24 m/sec and 1.85 m/sec. Four of the chutes supplied by Weba Chute Systems have been engineered to accommodate a Multotec cross belt sampler. The company is now in the design phase for additional chutes for the Khumani Optimisation Project (KOP), with installation scheduled to start in February 2013 as part of an interface with the WHIMS project.