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:: Service Contract for Swedish Grinding Mills
Metso Minerals has combined its competence and vast equipment range to ensure that unscheduled downtime in Sweden’s Boliden and LKAB grinding mills is minimised. Sweden’s New Boliden and LKAB mines receive a known cost and Metso Minerals ensures that unscheduled stops are kept a minimal level due to the Skega mill linings and Metso Minerals service concept.
New Boliden is a mining and smelting company focusing on production of copper, zinc, lead, gold and silver. The company is a strong European player with a significant global market position.
Their Aitik open-pit mine, is one of Europe's largest producers of copper, and also a major producer of gold and silver. Today, it mines some 18 million tonnes of ore annually. The mine, located in Northern Sweden, has nine Metso Minerals grinding mills; two 17x22 ft and two 22x42 ft mills. In total, Boliden has 28 grinding mills in sizes from 7x9 ft to 22x42 ft. These produce from 50 t/h to 550 t/h with feed fractions between 25 to 100 mm and discharges at 44 mesh. The grinding circuits are fully Autogenous grinding.
At Boliden, Metso Minerals is committed to minimise any unscheduled downtimes. "Unscheduled downtime is very costly for the mine," says Alf Norberg. He explains, "We are able to make these assurances thanks to the high-quality Skega Poly-Met lifters and Skega rubber plates together with our service-competence. Our service team has also to inspect the mills on short notice when the mills are down due to other reasons than mill linings."
"This is a clear advantage for Boliden and today they prefer this type of contract," he adds. Not only do Boliden reduce their costs, but in this case, Metso Minerals also assumes responsibility for planning, spare parts availability and the actual replacement of lifters and linings.
Alf Norberg continues, "Metso Minerals has a similar responsibility for major iron mine LKAB to ensure that unscheduled stops are minimised due to failure of the linings."
The LKAB mine processes 24-26 Mt crude ore per year. The iron ore, Magnetite, has a density of 2.9 - 3.2 t/m3 and a discharge fraction of 44 mesh from LKAB’s 35 grinding mills.
The mills vary in size between 10x12 ft to 22x28 ft. These produce between 100t/h to 600t/h. The mills are lined with Skega Rubber and Poly-Met linings, with a lifetime, depending on the mill, of between one to three years. The pebble mills with Skega Orebed linings last more that ten years
The Skega Poly-Met products combine the best properties of rubber and steel to maximum advantage. This combination makes it possibility to use harder and more wear resistant alloys of iron/steel than what can be used in a solid steel lining, as the rubber will absorb the impact forces.
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