840 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 preload consistency, eliminate bolt loosening and breakages and leakage. LMF® data was also used to assist in evaluating acceptable run-in and retorque timing. Figure 7 – Smart bolts installed and bolt tension in real-time. Using LMF®, high variability of bolt tension was noted (30-40% variance from target tensions), which was significantly greater than expected, and an overall low bolt tension — 2250 ft-lbs. Throughout the reline procedure, improper bolt installation, bolt thread damage, and bolt yielding were observed (Breininger, 2025). Also, during pre-installation, bolt damage was detected due to inappropriate packaging and storage. CLARABELLE SAG RELINE STRATEGY Mill availability is one of the most important indicators for overall equipment effectiveness. Maximizing operating time is fundamental for achieving production targets. Both planned and unplanned maintenance reduce availability and, consequently, mill throughput. Therefore, strategies and tools that minimize the frequency and duration of mill downtime are vital. Enhancing reliability, optimizing liner and component life, and improving maintenance efficiency all play a central role in increasing mill availability. At Clarabelle Mill, the SAG mill has historically required on average 4 planned relines per year, which represented approximately 4% of the mill’s annual availability.
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