Bunting Electro Overband Magnet Protects Gold Mine.

The largest Electro Overband Magnet ever built at the Bunting manufacturing plant in Redditch, UK is destined for installation in a gold mine in Northern Finland. Over a twelve-month operating period, the Overband Magnet will lift and separate damaging tramp metal from approximately 2.7 million tonnes of conveyed ore, protecting crushers, screens and other up-stream process plant.

The Overband Magnet is 4.2m long, 3m wide and 2.2m high, weighing just over 13 tonnes, and was built at Bunting’s UK magnetic separator manufacturing facility The Electro Overband Magnet is designed for positioning in a crossbelt orientation over the non-magnetic head pulley of a 1600mm wide conveyor, inclined at 12° and travelling at 0.75m/sec. The conveyed ore has a particle size range of between 70 and 400mm, varying in conveyed capacity between 450 and 765 tonnes per hour (equating to 2.7 million tonnes per year).

The tramp iron ranges widely in size and nature and includes steel rebar (2400 x 20mm dia.), cable bolts (600 x 15mm dia.), steel mesh, and broken drill bits. With a maximum working gap of 600mm (distance between the magnet face and the bottom of the ore conveyor), the Electro Overband Magnet is designed to lift and separate the tramp metal through a splayed burden of up to 500mm. This requires a substantially deep and strong magnetic field and related force density.

“Large mining projects, such as this, often require bespoke solutions,” explained Adrian Coleman, the General Manager of Bunting’s Redditch facility. “Over 40 years we have gained considerable experience in designing and building large Electro Overband Magnets. However, this was the largest we have ever manufactured at Redditch, presenting many challenges, which were overcome. And the design and manufacturing process all took place during the Covid-19 crisis.” 

July 2020