Chemical Technology May 2015

Two overbelt magnets from Multotec delivered to coal mining application

Multotec’s intimate understanding of miner- als processing and handling applications, coupled with its flexibility in being able to offer its customers fit-for-purpose solu- tions, 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 Mul- totec, says. “Multotec has a good standing within the Witbank/Middelburg coalfields area, where our products are supported by our local branches,” Slabbert says. Comment- ing 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 con- tinuous 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 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 pulley design, control and instrumentation. The overbelt magnets are suspended over the conveyor on gantries for easy re- moval for maintenance purposes. Features include an automatic belt-driven self-clean- ing system that dumps the tramp iron into collection bins at the side of the conveyor. The latest two overbelt magnets were

Longi-Multotec overbelt magnets are designed according to specific applications criteria.

Longi-Multotec overbelt magnets are engineered to effectively remove even the most challenging tramp metal.

ship 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. For more information contact Bernadette Wilson on tel: +27 11 923 6193, or email bernadettew@multotec.com, or go to www.multotec.com. grade concentrates and from concentrates contaminated with arsenic. FLSmidth recently filed patents for a new hydrometallurgy process called the FLSmidth ® Rapid Oxidative Leach that can economically remove the passivation layer of primary sulfides and thereby allow the extraction of copper. The technology operates at atmospheric pressure and temperature

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 partner- copper mineral most predominate in mines is however chalcopyrite (CuFeS 2 ), a refrac- tory sulfide mineral that is found deeper in the mine. Consequently, mining companies struggle to maintain copper production dur- ing the transition from oxide ore to sulfide ore as open pit mines reach the later stages of development. Mining companies also struggle to recover the copper from very low-

Giant leap in copper leaching technology A new leaching technology from FLSmidth can increase copper output by 3%, according to a recent report. That would mean an extra USD40million per year for an average copper mine with primary sulfide ore.

The top ore layer of an open pit copper mine is easily processed using heap leach in tandem with solvent extraction and elec- trowinning to produce copper cathodes. The

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Chemical Technology • May 2015