Patrick Ports and Stevedoring (Patrick) advised the ATSB that additional strapping is now being used to restrain each column of two adjacent ingot stacks. This is done by putting an additional strap around each two stack column (that is, one strap holds four 1 tonne ingot packs). Therefore, a 20 tonne lift has five additional straps and a 24 tonne lift has six additional straps.
According to Patrick, the additional straps stop the internal spread in each column by binding two stacks together, and reduce both the internal spread of each ingot pack and the risk of the top packs toppling out of the lift. The overall stability of the lift also improves (since the two stack columns are wider and, as a result, have a smaller height to width ratio).
Patrick also advised that it is continuing to look at the stability of unitised aluminium ingot packs and other ways to enhance their stability. The company will continue to consult key stakeholders, including Patrick employees, in this ongoing review of the stability of the ingot lifts.