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Practical Implications In a paper presented at MEI's Comminution 2014 conference, held in Cape Town earlier this year, Dr. Erik Hulthén, Magnus Evertsson and colleagues from Chalmers University of Technology and LKAB in Sweden described a study they had undertaken on optimizing cone crusher operation at the Malmberget iron-ore mine. As they pointed out, modern cone crushers are equipped to adjust the closed-side setting auto- matically to compensate for increasing wear over time. In addi- tion, the use of a frequency converter to adjust the eccentric speed means that this can now be done in real time, without the need to stop the crusher and change drive-belt positions. The study used a Sandvik CH680 cone crusher that is used to reduce 100-mm feed to minus-30 mm. In summary, the work showed that by selecting the optimum control points for the CSS and speed, the crusher efficiency could be improved signifi- cantly. There was also a marked increase in the output of minus- 1-mm material, meaning that later, higher energy-use comminu- tion stages would have less work to do. The authors noted that they are now developing a fully automated real-time algorithm, with the aim of consistently maximizing the circuit's output. The product and production development department at Chalmers has a long history of research into rock crushing, with a spin-off company, Roctim, now offering the "eYe" process optimization system that includes features such as Hulthén's real time optimization algorithms. Roctim has also developed its Crusher Control Unit (CCU) to supervise the crushing process and protect crushers from over- load and fatigue damage. The company noted that, at around half the price of major OEM systems, the CCU offers an alter- native solution for older crushers that have outlived their origi- nal control unit, or have never had one fitted. Various operating settings can be programmed into the unit's PLC, and the CCU can be operated either via a touch screen or through a site-wide HMI/SCADA system. Clearly, there are considerable incentives to operate crush- ers as efficiently as possible, while minimizing the risk of pre- mature wear and failure. Modern drive and control systems have gone a long way to achieving these aims, bringing better ener- gy efficiency and higher, more consistent output to the crush- ing process. JUNE 2014 • E&MJ; 61 www.e-mj.com C R U S H E R S Sandvik's ASRi can be run in Auto-load or Auto-CSS modes, allowing easy collaboration. EMJ_pg58-63_EMJ_pg58-63 6/3/14 3:06 PM Page 61