Project Scope:

  • EDC was engaged to investigate an excessive vibration issue of BHP’s RC701 slew drives which had resulted in repeated cracking failures of the slew drive mounts.
  • Proceeding identification of the vibration root cause from site measurements, EDC was required to use FEA to develop a design modification which mitigated the slew drive vibration levels.


  • Delivering a feasible design modification within a tight schedule for installation during the next planned shutdown.


  • The vibration root cause was identified as operation through two natural frequencies of the slew drive mounts. These were a ‘vertical bounce’ and ‘lateral sway’ of the slew drive mounts.
  • Amplification footage confirmed that the mounting plate bolts for the slew drive was loosening.
  • Provided a design modification which shifted the natural frequencies above the maximum operating slew speed.