Figure 8 – SAG Mill reline strategy: one shutdown to align and replace all high wear components: (1) feed chute liner, (2) FE liners, (3) shell liners, (4) DE liners and (5) trommel panels Feed Chute Liner Redesign – Root Cause and Upgrades Chronic plugging events on the SAG mill feed chute was another major SAG availability detractor. Root cause analysis uncovered causes of problem: ● Oversized rock box design, massive ore bed provided protection against liner wear but failed to form a consistent slope for ore travel ● Poor ore slope conformation and inadequate compaction, preventing consistent ore flow through the spout ● Too sensitive to ore oversize and scrap metal from mines To address these issues, Clarabelle’s engineering team developed the concept and detail engineering of the chute design. Rock box and liners were modified to optimize material flow, improve wear performance, and mitigate plugging. Trommel Panel Life In 2025, the trommel panel design was modified to increase its lifespan in order align with the SAG relines. Despite the high confidence in achieving the targeted lifespan, the new design exhibited a lower classification efficiency and as such, the plant decided to revert to the previous design to ensure operational stability. Clarabelle will continue to pursue panel lifespan improvements, while ensuring classification efficiency, to align with the SAG reline strategy. Condition-Base Liner Maintenance Since 2024, Clarabelle’s SAG mill has adopted an in-house Condition-Based Maintenance program for SAG liner integrity control. Routine inspections now include systematic 3D laser scans and liner ultrasonic thickness (UT) measurements to track wear. Figure 9 shows the drone-assisted inspections (Helliun, 2025) that eliminate the need to pull the feed chute for liner accessibility, reducing downtime, increasing plant personnel safety, and improving inspection quality.
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