Modular construction techniques commonly used in the oil and gas industry for decades are now being successfully applied to some of the largest mining projects ever undertaken in Australia.
Global engineering, project delivery and sciences firm, Sinclair Knight Merz (SKM), has established new benchmarks in project delivery, engineering design and construction practices for a series of projects, including the recent 261 m extension of a finger wharf 3 km off-shore from Cape Lambert in Western Australia, for Rio Tinto Iron Ore.
After fabrication in China, 7 wharf modules were transported by heavy lift ship to the site, transferred onto the piles and welded into position, with a fully modularised ship loader also being installed on the wharf.
The wharf modules also included electrical and piping services, mechanical equipment, conveyor idlers and some of the drive stations.
A major aspect of the Cape Lambert project was the modularisation of fully assembled and fitted out berthing dolphins, complete with fenders, deck furniture, quick release hooks and safety infrastructure, each weighing 180 tonnes.
SKM is currently investigating several off-shore wharf projects for other clients that will maximise the use of modular construction.
Whereas all land-based machines for stackers and reclaimers would have traditionally been assembled after arriving in pieces on a construction site, these machines are now landing fully assembled on shore and then being transferred onto large multi-wheel self-steer platforms.
They are then driven on a purpose-made road to site, where they are installed on rails to be operated as stackers or reclaimers.
The company also applied the modularisation technique to the $US1.4 billion expansion of Rio Tinto’s Dampier Port facilities in Western Australia, which recently won the Resource Development category at the Australian Engineering Excellence awards, following the project being declared the most outstanding engineering achievement at the Engineers Australia, Western Australia Division awards.
The key to the successful delivery of the largest project in the expansion programme, according to the company, involved a world-first modular approach to heavy wharf construction that reduced on-site labour, while creating new levels of workplace safety.
Phase A included extending the wharf by 450 m to create two additional shipping berths, a car dumper facility with provision for an adjacent facility, an extension to the stockyard (including four new stackers and a new bucket wheel reclaimer), a screen-house facility and a shiploader.
During Phase B, the wharf was extended by an additional 150 m to create the final four-berth configuration, and an additional car dumper and screenhouse facility, and a new shiploader was installed on the extended wharf.
Modularisation of primary steelwork and the mechanical / materials handling elements of the project enabled it to be completed on budget and ahead of schedule, according to the company, resulting in a doubling of the Dampier Port’s capacity from 74 to 140 Mtpa, and setting a new industry safety benchmark of five million man hours Lost Time Injury (LTI) free.
Halfway through the first phase of the project in 2004, the wharf site construction schedule came under pressure due to major skills shortages in the construction sector.
With the wharf being the critical path, a new approach was needed.
The wharf team developed a modular approach to wharf construction that would open up a third work front in Perth and allow the installation of prefabricated wharf modules by heavy lift vessel at Dampier.
The modularisation of the wharf deck in both Phases A and B represented a ‘first’ for bulk materials handling wharves.
This involved construction of the wharf decks in 350 tonne modular arrangements on land at Henderson, Western Australia, then subsequently transported to site by heavy lift ship, placing them directly onto the wharf pile caps.
The change to a modularised approach during Phase A was driven by schedule pressures and site labour constraints. This method of construction, which was also employed for Phase B, has now become the ‘industry standard’ for heavy wharf construction and has been used for other iron ore wharves in Australia.
While doubling the load-out capacity, the design and construction had to allow for a further wharf extension as forecast ore sales continued to increase.
The wharf extension and two new berths were purposely designed to allow a further 150 m extension of the berthing positions to create a four-berth wharf with a second new shiploader as part the Phase B project.
By re-thinking the construction plan from a ‘stick-by-stick’ traditional building method to prefabricating 4 X 54 m modules, the project team was able to accelerate the project and overcome labour shortages.
Simple in concept, yet revolutionary in practice, the project team effectively moved the entire structural fabrication effort several thousand km down the coast to the Australian Marine Complex (AMC) at Henderson, south of Perth.