Master Magnets Supply Largest Permanent Overband Magnet To South Africa
- 17 May 2012
- Company & Industry News
After an extensive internet search, Anglo American (a subsidiary of Anglo Operations) contacted Master Magnets to provide an Overband Magnet for their New Vaal Colliery located in Vereeniging on the Free State bank of the Vaal river about 70 km south of Johannesburg.
The mine was established in the 1980s to exploit the remaining reserves in the area for the supply of low grade coal to Eskom's Lethabo Power Station until 2030. The mine produces at a rate of almost 18 million tonnes a year, and operates open-cut strip mining methods to extract remnant coal pillars left from underground mining that took place in the area during the 1960s. The initial request was for an overband situated over a 2,300mm wide belt with a burden of 350mm of coal and Master Magnets offered an electro-magnet design due to the high burden depth, but after initial consultations Anglo American stated that they required a permanent magnet.
Master Magnets' standard range of Overbands is one of the largest offered by any magnet supplier, including a magnet capable of handling material with a burden depth of 300mm, however even this would not have been strong enough for the process at New Vaal.
Master Magnets therefore used their extensive knowledge and state-of- the-art magnet design program to create a special magnet, suitable for this greater burden. Due to the heavy burden of coal and the tramp metal that could be found within the process, Anglo American were concerned with the damage that could be caused to the Overband's belt and the amount of downtime that this would lead to.
Therefore Master Magnets discussed the options of armoured belts and the best material for this armouring. Due to the size of the unit it was determined that the best material would be a HDPE plastic, which has the advantage of high wear characteristics, but enough flexibility that the material will pass over the crowned head pulley and take impacts from tramp metals. Before placing the order, Anglo American decided that the idea of Master Magnets armoured belting could be extended to other Overbands on their site and ordered 2 more belts for competitors' machines.
By the beginning of February all of the financial terms had been settled and Anglo American had placed their order. Despite the design being completely new to the existing Mastermag range, the Overband and the additional armoured belts were also ready for collection on the 20th March. Anglo Americans Overband Magnet will undoubtedly be one of the world's largest Permanent units in operation and whilst many competitors would have considered a unit of this size as outside the scope of their supply, Master Magnets has always prided itself on being able to manufacture innovative solutions that will deal with these types of applications.