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 preinstallation, bolt damage was detected due to inappropriate packaging and storage. 3. 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. Synchronization of SAG Mill Wearable Components and Reline Intervals Historically, SAG reline schedules were tonnage-based and followed a staggered replacement sequence; with the shell liners, discharge-end liners, and feed-end liners changed at different intervals throughout the year (Figure 8). The SAG reline was one of the largest contributors to the mill planned downtime. In 2023, to improve this, Clarabelle transitioned from tonnage-based to a thickness-based strategy, enabling all high wear liners to be replaced in a single shutdown, reducing from 4 to 3 relines. By improving the liners design and aligning the lifespan of the feed chute, feed-end liners, shell liners, discharge-end and trommel panels (Figure 8), the reline frequency was successfully reduced to 2 relines per year in 2026.
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