Mechanical Technology may 2015

⎪ Materials handling and minerals processing ⎪

Overbelt magnets delivered to coal mine

Following the successful completion of an order placed in September 2012, Multotec has received a repeat order for two 33.7 t overbelt magnets for a second phase expansion project at a Witbank/ Middelburg coalfield.

M ultotec’s intimate un- derstanding 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 the suc- cessful commissioning two years ago of two overbelt magnets at another coal mine in the same group,” Willem Slab- bert, process and applications manager at Multotec, says. “Multotec has a good standing within the Witbank/Middelburg coalfields, where our products are supported by our local branches,” says Slabbert. Commenting on the latest order, he ex- plains that the application is to remove tramp metal from run-of-mine

Right: Multotec’s Magnetics Division assembly team standing next to a locally manu- factured 33.7 t Longi-Multotec overbelt magnet.

material in order to prevent it from entering coal gasifiers. “This is a critical ap- plication as the coal gasifiers have ver y stringent tramp metal removal specifications,” Slabbert says. Tramp iron traditionally removed from coal carrying conveyors includes sections of continuous

Above: Longi-Multotec overbelt magnets are designed to remove tramp metal from run-of-mine material in order to prevent it from entering coal gasifiers or mill circuits. Left: Longi-Multotec overbelt magnets are engineered to effectively remove even the most challenging tramp metal.

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 require- ments more quickly, and 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 engi- neers that is able to assess a customer’s specific application requirement, taking into account factors such as 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. q

over the conveyor on gantries for easy removal for maintenance purposes.

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 over- belt 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 pul- ley design, control and instrumentation. The overbelt magnets are suspended

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 low bed trucks, and weigh 28 t each without their 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 mag- net. 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 8.0 t each being the norm. Slabbert confirms that these are the largest overbelt magnets available in

Mechanical Technology — May 2015

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