consolidating the wear zone and enabling replacement of one liner instead of multiple smaller pieces. Discharge End Liner During the shell liner failure investigation, it was determined that chronic breakage to the DE intermediate liners were related to the poor shell liner design (which promoted increased media/ore impact onto DE liners). Poor discharge-end liner face angles also can contribute to discharge end impacts by throwing material onto itself. To reduce peening, the face angle was increased from 1° to 10°. To extend liner life, the lifter height was increased by 31 mm. The grates were modified to curved ribs; slot size maintained at 2” as well as the total grate slot/open area. These dimensions were used to keep the mill’s overall volume consistent with the original design. Discharge Deflector Cone Original deflector cone chronic failures had caused significant mill downtime due to poor bolting design. The “Bullnose®” cone design was selected to mitigate multiple failure modes such as inner pulp lifter bolt and deflector cone bolt failures as well as accelerated wear on the inner pulp lifters. This cone design integrated the existing inner pulps and DE liner plates into one piece, and the number of components were also reduced from 20 to 9 pieces, which further reduced reline time. Smart Liner Bolting During installation of the new liners, the Load Monitoring Fastener (LMF®) BoltSense technology was commissioned to verify and improve bolting practices (Figure 7). The objective was to improve pre-load consistency, eliminate bolt loosening and breakages and leakage. LMF® data was also used to assist in evaluating acceptable run-in and retorque timing.
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