Bradken Bolt Optimisation and Load Monitoring Fastener (LMF+)

A mining customer experienced an unusually high rate of bolt breakage in both of their SAG mill shell liners, with up to 50% of bolts failing during operation. These breakages occurred in various bolt head configurations, including oval head bolts, stud and spherical head assemblies, resulting in unplanned mill shutdowns and reduced production. The breakages were a result of insufficient bolt tension.

The broken bolts also posed a significant safety risk, as they could be ejected from the mill during operation, potentially causing injury to workers.

Bradken collaborated with Copper State Bolt & Nut Company and the customer to undertake an on-site audit focusing on a review of the installation procedure and bolt design. As a result, an enhanced installation procedure was developed to ensure the bolts were installed effectively.

To mitigate the insufficient bolt tension, the team implemented advanced Load Monitoring Fasterner (LMF+) technology, which utilises strain gauges to enable real-time bolt tension monitoring. The system provides immediate feedback via an iPad interface, delivering exceptional visibility and control during both installation and ongoing operation.

Since the implementation of the Load Monitoring Fastener (LMF+) technology and improved installation procedures in 2023, there have been no reported bolt failures on the mill shells, a significant advancement in both reliability and safety.

Building on this success, Bradken is now working collaboratively with the customer to extend the trials to the discharge end of the mills, further addressing bolt breakage concerns. This proactive initiative has not only improved mill performance and operational safety but also strengthened Bradken’s reputation as a trusted partner in delivering innovative solutions and driving operational efficiency.