A bucketwheel reclaimer had been decommissioned after 25 years due to extensive structural defects, including cracking in the luffing pivot rocker region.
For these defects to be repaired, the traditional approach would be to fully dismantle the reclaimer in the reverse order to which it had been constructed, however this would require an extensive laydown area, high capacity cranage and months of construction work with the associated high risk. Another alternative would be the complete replacement with a new reclaimer, which would require a significant cost and timeframe for the procurement and commissioning of the new machine.
Instead, an in-situ structural remediation solution was undertaken which enabled the client to resume operations in 12 months, sooner than a traditional refurbishment and at a cost saving of several million Australian dollars.
The major remediation works included:
Repair of structural cracking in the rocker arm assembly.
Hydraulic luffing cylinders were removed, refurbished and re-installed.
Slew bearing replacement.
Bucketwheel replacement, including shaft and drive assembly.
Replacement of heavily corroded structural members on bucketwheel boom.
The superstructure of the reclaimer was lifted in-situ with the boom and counterweight still assembled, which allowed the change out of the slew bearing and the repair of the rocker assembly.
This implementation required purpose-built temporary luffing cylinders, temporary support frames, and the installation of safety features such as strain gauges to monitor the loads and stability throughout the construction process.