The remediation and rebuilding of the Groote Eylandt Mining Company wharf is one of Australia’s most ambitious marine recovery efforts.
When Tropical Cyclone Megan struck Groote Eylandt Mining Company (GEMCO) wharf in March 2024, it brought a critical export lifeline to a halt.
The wharf, located in the Gulf of Carpentaria and a key gateway for manganese exports essential to global steel production, was left in ruins. Nearly 2000 t of debris, including twisted steel and fractured concrete, were scattered across the seabed.
What followed was one of Australia’s most ambitious marine recovery efforts. Led by McConnell Dowell, the 12-month remediation and rebuild project has since been recognised as a finalist in the Australian Construction Achievement Award – a reflection of both its scale and the ingenuity required to deliver it.
But beyond the engineering challenge, the stakes were human.
“The disruption not only caused major economic losses through reduced exports and disrupted supply chains, it impacted local government revenue, the workforce dedicated to the mine and the local indigenous community,” said Gert Olivier, Operations Manager QLD and NT for McConnell Dowell.
A project defined by complexity
From the outset, the project was far from straightforward.
“It called for the integration of structural, subsea and marine engineering disciplines, with a significant portion of the risk and complexity driven by the need to safely remove, and work around, submerged cyclone debris,” Area Manager Keith Miles told create.
“At the same time, we needed to deliver new infrastructure within a constrained and constantly changing environment, to a tight schedule.”
Miles said significant portions of the wharf had collapsed, leaving debris both above and below the waterline, meaning all works had to be carefully staged to avoid further destabilisation.
“To rehabilitate the damaged wharf, a flexible program to stabilise the existing structure, clear the debris from the seabed and then rebuild the infrastructure, needed to be developed,” Olivier said.
The team would have to work alongside environmental challenges such as extreme heat and frequent thunderstorms.
A large marine fleet consisting of two large jack-up barges, two smaller jack-ups, a 250 t crane barge, three flattop storage barges and a support fleet of tugs and work punts from Australia, Singapore and the United Arab Emirates were mobilised to perform the works. In addition, an international workforce of 176 people worked day and night.
“Due to the instability and stored energy within the damaged structure, detailed demolition plans had to be developed and approved. To ensure we kept people out of harm’s way, as many activities as possible were performed through mechanical means. If this was not possible, alternative work sequences or work locations were considered.”
Excavators fitted with hydraulic shears working from smaller jack up barges cut sections from the damaged structure and dropped these to the sea floor to be retrieved by divers at a later stage.
Divers worked more than 500 commercial dives, in low visibility, cutting and segmenting submerged structures.
Above the surface, crane barges and jack-up platforms executed precision lifts, requiring detailed engineering including ballasting and stability management, each dependent on the other to maintain safety and progress, Olivier said.
In total, 1037 t of concrete and 998 t of steel were safely removed from the seabed, with salvage operations unfolding in waters inhabited by sharks, crocodiles and stingrays.
Advanced subsea technology played a critical role in accelerating the recovery while reducing risk. Sonar mapping and remote operated vehicles allowed teams to identify and track debris with precision. Simulation and modelling tools helped plan demolition sequences before work began, while real-time data improved coordination between divers and crane operators.
A GPS locator system helped guide divers to work points despite limited visibility, while Blueview Imaging provided a clearer picture of the seabed.
Rebuilding at pace
Once the site was cleared, the focus shifted to reconstruction, Olivier said.
In under two months, the team installed 28 new piles, 13 large prefabricated modular steel units and 62 steel trusses, a pace made possible by planning and a reliance on offsite fabrication.
Rather than building everything in situ, large structural components, including trusses over 60 m long, were manufactured elsewhere and transported to site.
“The sequencing of transport, positioning, lifting and installation was critical, as any delay or misalignment in one activity would directly impact the overall program,” Miles said.
Each lift required detailed engineering, from vessel stability and ballasting to managing wave and interaction forces.
“Material management was critical, with minimal laydown space requiring offshore staging and just-in-time delivery of components.”
Engineering under uncertainty
Geotechnical challenges added further pressure. With limited data available, pile installation demanded continuous analysis and adjustment.
“Before the piling crew could move to the next piling position, we needed to confirm pile capacity through pile-driving analyses. Continuous communication with the designer ensured no time was lost,” Olivier said.
Toward the later stages, works had to be undertaken within a live port environment, requiring continuous coordination with Port Control and the Harbour Master for vessel movements, site access and safety systems.
But by mid-2025, the rebuilt wharf, named Barrarumanja, was ready to be opened.
Not only has it allowed a return to full export capacity, but it is designed to better withstand future cyclones through stronger pile connections, elevated deck levels and more robust structural redundancy.
“This project is a powerful reminder of what can be achieved when a client and contractor come together with a shared goal and a collaborative mindset,” Olivier said.
Do you know an innovative engineering project worth of recognition? Nominate it for the 2026 Engineers Australia Project of the Year.
