Dalrymple Bay Coal Terminal – DBCT were looking for a significant change in their old practice of painting the piles supporting the jetty structure. John Holland Group (JHG) partnered with DBCT and developed a procedure of wrapping the piles with tape to protect the existing paint from wave damage rather than repainting. The existing method of accessing the piles involved building scaffolding over the conveyor houses and underneath the roadway, a process that would take a week to wrap two piles. With more than 120 bents, the name for the piles and headstock, to be wrapped the process was going to take several years.
JHG proposed the concept of a gantry that travels along the existing roadway with a structure wrapping over the conveyor tunnels and supporting davits that swing underneath the jetty, with swing-stages that access the piles. JHG approached CMP Engineers to design and supply, through Loadquip, the mechanical systems required to make the design work.
To clear the headstocks between the conveyor houses, a mast that can be raised for transport and lowered for use of the swing stages was designed. A wire rope reeving system, with redundant ropes and a load sharing mechanism, supports the mast. Nylon rollers specifically designed for rigidity and low friction, support the mast while it’s being moved. A hoist cylinder raises the mast and integrated hydraulic valves prevent any uncontrolled movement.