Key components of Stage 2 of the project, designed to increase coal throughput from 68 million tonnes per annum to 85Mtpa by year-end, include construction of a third offshore out-loading conveyor and extensions to the existing 1.1km wharf to expand ship loading capacity.

 

The wharf extension is being constructed using a moving steel assembly called a canti-traveller.

 

Coates group product development manager Rafi Tchopourian said an Enerpac synchronous lifting system was first used to hoist precast concrete sections – weighing more than 80 tonnes each – clear of the ground to determine the exact weight of the assembled units before a crawler crane was allowed to lift them into place on the canti-traveller.

 

The lifting system controller determines the load in kilonewtons at each lifting point, using information provided by sensors that precisely measure hydraulic oil pressure.

 

“This offers added control of the load movement, while the weight and the centre of gravity can therefore also be calculated,” Tchopourian said.

 

“The value of the load is displayed on the screen in kilonewtons.”

 

The second part of the process involved lifting the canti-traveller to determine its weight then tilting it from side to side, then front to back, to allow Connell Hatch engineers to determine its structural rigidity.

 

Once the structure had been analysed, the crane perched on top of the canti-traveller was slewed to various locations and the jib luffed to various angles to determine the point loadings on the rolling components of the canti-traveller before it could be placed into operation.

 

Synchronous lifting systems can be configured with up to 64 jacking cylinders ranging from 10 to 1000 tonnes capacity. They have been proven in a wide range of engineering tasks, from splitting a 3500t dragline at Curragh in Queensland for routine maintenance to the construction of the world’s highest bridge, the 343m-high Millau Viaduct in France.

 

Enerpac engineering manager Tony Cooper said each step of even the most complicated lift could be followed on screen.

 

“In addition to time saving and the exceptionally accurate and virtually stress-free movement of an object, the advantages of synchronous lifting include its ability to record and document the entire repositioning process,” he said.

 

“All the values are stored in the control systems memory for later use. With satisfactory progression of the procedure, this provides the contractor and the client with a clear guarantee that excessively high stresses have not occurred.”

 

Cooper said simplicity was the key to the system. “Just specify the tolerance, specify the target, and start lifting,” he said. “After that, all you have to do is ensure that everything is proceeding smoothly.”