Multotec’s intimate understanding of minerals processing and handling applications, coupled with its flexibility in being able to offer its customers fit-for-purpose solutions, has resulted in a repeat order for two overbelt magnets sold into a coal mining application in the Witbank/Middelburg coalfields. “This order follows on from the successful commissioning two years ago of two overbelt magnets at another coal mine in the same group,” Willem Slabbert, Process and Applications Manager at Multotec, says.
“Multotec has a good standing within the Witbank/Middelburg coalfields area, where our products are supported by our local branches,” Slabbert says. Commenting on the latest order, he explains that the application is to remove tramp metal from run-of-mine material in order to prevent it from entering coal gasifiers.
“This is a critical application as the coal gasifiers have very stringent tramp metal removal specifications,” Slabbert says. Tramp iron traditionally removed from coal carrying conveyors includes sections of continuous mine core breaker teeth, conveyor belt idlers, belt joints, wire, roof bolts, metal plates, slings, picks and pick cases, cable hooks, expanded metal, tools, tin cans and other such objects.
Multotec supplied the original two overbelt magnets in September 2012, with the latest order representing the second phase of an ongoing expansion project. Stuart Cullum, Process Engineer, explains that the width of the conveyor belts in this coal mining application is 1.8 m, with the overbelt magnets themselves being 5.1 m wide and 2.45 m high. They incorporate the latest technical specifications of the client, including pulley design, control and instrumentation.
The overbelt magnets are suspended over the conveyor on gantries for easy removal for maintenance purposes. Features include an automatic belt-driven self-cleaning system that dumps the tramp iron into collection bins at the side of the conveyor.
The latest two overbelt magnets were transported to Mpumalanga on lowbed trucks, and weigh 28 t each without cooling oil. The latter is added once on site using an oil tanker, with a final total weight of 33.7 t for each overbelt magnet. As per client safety specifications, the overbelt magnets have eight safety chains rated and certified for a load of 16 t each. This is double the normal requirement, with four chains rated at 8 t each being the norm.
Slabbert confirms that these are the largest overbelt magnets available in the Longi-Multotec range. “Through our partnership with Longi, Multotec now has access to a comprehensive range of off-the-shelf air-cooled overbelt magnets for underground tramp metal removal, with the option of flame proofing.” Having a standard range on hand means that Multotec can meet customer requirements far more quickly, as this reduces lead times significantly.
Multotec is one of the largest suppliers of overbelt magnets in Africa, for a range of commodities from coal to iron ore. It has a dedicated team of expert engineers who are able to assess a customer’s specific application requirement, taking into account factors such as the conveyor belt speed and size, burden depth, the properties of the load on the belt and the size of the tramp metal that must be extracted.