activities: • All dimensions in stress-critical regions must align with the design intent, including material thicknesses, weld sizes, radii, bolt circle diameters, and other specified features. • All welding should comply with an appropriate standard (AWS D1.1 or equivalent). • Welds must be treated as required by the design, including processes such as grinding or peening. • Comprehensive non-destructive testing (100% coverage) should be carried out on all welds and castings to ensure material integrity and freedom from defects. • All surfaces must be smooth and free from sharp transitions, gouges, impressions, or other unnecessary stress-raising features. • All flanged connections must meet tolerance requirements. The above is achieved by utilizing trusted mill vendors, with proven subsuppliers, who have developed and adhere to stringent manufacturing specifications, procedures, and Inspection and Test Plans (ITPs). These ITPs must be supported by suitably qualified and experienced inspectors and Non-Destructive Testing (NDT) technicians. This ensures the structural stress is as calculated, and that the material strength is equal to or greater than the required limits. A final consideration for fatigue performance is the equipment condition. From a fatigue standpoint, the two most common contributors of reduced fatigue resilience are inadequate bolt preload and material washout. Consistency and accuracy in fastener tensioning during installation, followed by appropriate post-commissioning tension checks, are essential for achieving reliable long-term mill operation. This requires each bolt to be tensioned to its specified elongation and verified using ultrasonic bolt-tension measurements under the supervision of an experienced mill installer. When the bolted connection design is robust, routine retensioning is generally unnecessary once operational loads have stabilised; however, it remains best practice to periodically spot-check a selection of fasteners as part of standard maintenance procedures. In recent years, online fastener-monitoring systems have become increasingly accessible, providing a practical means for continuous remote monitoring and risk mitigation. Washout is the localised loss of material from a mill component caused by slurry flowing between or beneath the protective liners. It most commonly results from incorrectly installed liner or poor maintenance. Once slurry passes between liner segments, it erodes a groove, channel, or cavity in the underlying component. The resulting reduction in wall thickness increases local stresses in and around the damaged area. Depending on its location, this elevated stress can significantly reduce equipment life or, in severe cases, lead to catastrophic failure. In most cases, washout can be prevented with diligent liner monitoring practices. This should include regular in-situ liner scans, liner wear reports, and Discrete Element Method (DEM) based liner wear prediction and optimization. Two examples of fatigue failure are detailed below. While no root-cause analysis has been conducted by the author, these cases are presented to demonstrate common
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