Engineering and Mining Journal - Whether the market is copper, gold, nickel, iron ore, lead/zinc, PGM, diamonds or other commodities, E&MJ takes the lead in projecting trends, following development and reporting on the most efficient operating pr
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P R O C E S S I N G S O LU T I O N S Arrangement and typical operating conditions for Xstrata Technology's IsaMill. nitude 7 earthquake, due to the highly active seismic setting for the project. Xstrata Technology recently also highlighted an expansion of its IsaMill product line. In its Update newsletter, the company explained that bigger tonnages and lower grades are leading to a demand for larger scale comminution equipment, particularly in porphyry copper and magnetite operations. It has responded by working with partners Netzsch and Linatex to design the largest lsaMill, the 8-MW M50,000. Greg Anderson, technical manager for the M50,000 lsaMill project, said, "Most of the challenges involved with the larger mill design were related to the size and weight of the equipment, particularly in manufacturing, and for ease of shipping and general handling. Operationally, we expect the same energy efficiency as we achieve when we scale up from a M4 to a M10,000 mill. The grinding action and media is still the same, it's just at a much bigger scale." Anderson said several significant developments have evolved from the effort, including novel liner design and new relining technology, some of which may also be used for smaller lsaMills. The M50,000 has eight discs— weighing 2 metric tons each—to provide the media stirring in the mill. Because their weight ruled out handling by cranes when replacement is www.e-mj.com required, a maintenance system has been incorporated to move the components on and off the shaft. It uses a system of hydraulics, already in place on the shell, and an innovative rotating head with "fingers" to lock into place on the worn components on the shaft. The operator remotely controls the equipment to remove the components from the shaft, and reload new components back on the shaft, using the same tool. The company said it expects that a full set of discs could be replaced in eight hours. The bigger mill has a new segmented shell liner so all components can fit in shipping containers. Each segment has a purpose-designed O-ring type sealing and flange system to produce a complete seal when the sections are compressed together. The outer shell of the mill has been reconfigured into segments to allow removal and installation of the inner liner segments. The outer shell will be rotatable about its axis to facilitate maintenance on the liner segments as well as to allow liner life to be optimized. Anderson said the new mill would provide an option for large-scale operations that want to use just a single lsaMill in their regrind circuits, while still receiving the benefits of the mill's energy efficiency and inert grinding performance. Computer graphic shows prototype relining machine designed for M10,000 and M50,000 IsaMills. JANUARY 2014 • E&MJ; 73