Introduction

In operation since 1972, the Paraburdoo stackers have performed well beyond their design life. The stackers, however, no longer complied with current safety standards and started to develop structural integrity concerns, resulting in Rio Tinto’s decision to replace them. During their operation, the Paraburdoo stackers had only minor electrical and mechanical upgrades but otherwise remained basically unchanged since commissioning.

As part of this Project, Rio Tinto’s contractor was tasked with delivering the execution of these deconstruction works including a detailed deconstruction methodology, verification of the stability of the Stacker throughout the deconstruction process, design drawings for lifting points and the final lift plans.

The team at Andvare were consulted as a deconstruction specialist for third-party verification in both the deconstruction planning and execution phases. In particular, on-site support for the contractor provided added value for the client, streamlining the change management process and leading to a safe and efficient implementation.

Issues

The Stackers had reached the end of their serviceable life and were to be replaced.  The following issues were identified during the scoping of the deconstruction works:

• A previous deconstruction incident highlighted the need to proactively manage critical risks during deconstruction works.
• The deconstruction works were required to be completed over live conveyors and to suit the stacking and reclaiming requirements of the Operations team.  It was anticipated that plans may need to change at short notice to ensure that train loading activities were not unduly impacted by the project.
• In particular, the counterweight areas of the stackers required on-site inspection for confirmation of mass due to a lack of available information.

Solution

During the methodology development stage, the team at Andvare provided third party review to identify issues and shortfalls. These were appropriately addressed in consultation with both the client and the contractor before committing to an approved site execution plan.

Working in close communication with the contractor, Andvare’s on-site deconstruction specialist provided expert support updating and refining lift studies through performing detailed inspections, measurements and test lifts. From this, Andvare reviewed and approved the machine mass-balance calculations to ensure stability and safety throughout deconstruction.

Changes to the deconstruction methodology were also checked and updated to ensure that the revisions were safe to implement. Where required, calculations were performed to certify the safe lifting of existing machine structures.

Benefits

• Disruption to the operation of the Stockyard was minimised.
• Lift plans could be safely updated and changed to reflect differences between the planned lifts and the required on-site implementation.
• Changes to the deconstruction methodology to meet Operational requirements could be made at short notice meaning that client induced delays to the original contractor’s project execution were minimised.
• Due to Andvare and the Teams expertise, the project was safely and successfully completed within the budget and timeframe.