Dragline Deflection Sheave Towers.

Dragline deflection sheave tower assemblies comprise the structural tower and complete sheave system used to support, guide and redirect the operating ropes through the required path between the machinery house, boom and bucket systems. The assemblies must withstand continuous cyclic loading, vibration and changing rope forces while maintaining accurate sheave positioning and smooth rope travel.

MEA was engaged by BMA to undertake the refurbishment, structural repairs and access upgrades of the dragline upper and lower boom deflection sheave tower assemblies for Norwich Park Mine, completed within a compressed turnaround during the dragline's scheduled major shutdown.

The refurbishment scope included the complete strip-down and overhaul of the deflection sheave assemblies, with replacement of bearings, seals and associated components. Sheave grooves were hardness tested to assess wear condition, while 100 percent magnetic particle inspection was completed across critical joints and high-stress areas to identify surface cracking and defects.

The supporting tower structure was thoroughly inspected and required a number of crack repairs, weld rectification works and additional structural bracing to improve strength and long-term reliability. MEA also designed, fabricated and installed upgraded access platforms, ladders and safety handrails to improve maintenance access around the sheave assemblies.

Following refurbishment, the sheaves and associated components were reassembled, aligned and inspected prior to return to service. All engineering, fabrication and mechanical works were coordinated to meet the shutdown schedule and minimise dragline downtime.