● Grinding efficiency—the liner design shall improve throughput (tons per hour), support optimal charge motion and optimize power consumption. The SAG mill operational control was also determined. Liner material compositions were reviewed, and it was decided to maintain the chromium-molybdenum steel alloy and same total liner weight in order to not compromise the SAG mill power and integrity capacity. Optimized Hi-Hi Shell Liner The new customized shell liner configuration was a 40-2 row Hi-Hi lifter with 35° face angle. As shown in Figure 6, mill charge trajectory simulations, designed for 30% of total volumetric charge (18% of ore and 12% grinding media), indicated that the SAG mill should be initially operated with an upper limit of 10.4 rpm (note: SAG operates at variable speed; min: 8 rpm / max: 10.8 rpm). To maintain the optimal charge lift and trajectory throughout the wear cycle, the operating speed should be incrementally increased to 10.8 rpm over the liner life cycle. In addition, the new liner set was designed with larger pieces, decreasing the number for shell liner pieces from 180 to 80. This reduction further decreased reline time (25 hours) and permitted safer installation. Figure 6 – 40-2 row Hi-Hi with 35° face angle, Bradken’s MILLSIM charge trajectory simulation @ 10.4 rpm, and liner packing mitigation. Feed End Liner To address the pegging, the pinch points between the top of the side rib and the main lifter were reduced by shortening the sides of the rib to eliminate gaps where balls were previously trapped. To extend liner life, the lifter height was increased by 38mm, and the leading face angle was modified from 4° to 25° to reduce peening thereby minimizing direct high-energy impact on the liner face. To reduce reline time, the total number of components was reduced from 42 to 36 by integrating two liner segments into a single larger casting,
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