A major piece of South Australia’s biggest infrastructure project has been lowered into place, with the third and final large-scale Tunnel Boring Machine cutterhead now craned into position for the $15.4 billion River Torrens to Darlington Project.
The massive cutterhead, weighing more than 300 tonnes, was carefully lowered into the 20-metre-deep launch box at the project’s Central North Precinct in Hilton using a 500-tonne gantry crane.
It marks another visible step forward for the T2D project, which will eventually complete the long-awaited non-stop South Road corridor and change the way traffic moves through Adelaide’s inner west and south.
The project is set to make Australian history as the first road project in the country to operate three large-scale Tunnel Boring Machines at the same time. Each machine is around 100 metres long and 15 metres in diameter, making them roughly the height of the Thebarton Theatre or the goal posts at Adelaide Oval.
Federal Infrastructure, Transport, Regional Development and Local Government Minister Catherine King said the milestone showed the project was gathering pace.
“The T2D Project will transform the way people move through and around Adelaide and progress is now really accelerating on this exciting project.
“This is the city changing infrastructure that is achieved when Labor Governments at state and federal levels can work together to get things done.”
The final TBM will be used to construct the Northern Tunnels, launching from Hilton and digging 2.2 kilometres towards the Northern Precinct near Brickworks Marketplace in Torrensville. Once it reaches the northern site, it will be turned around before tunnelling back to Hilton.
With the cutterhead now in place, crews will continue assembling the remaining TBM components before final testing and commissioning. Tunnelling is expected to begin in the second half of 2026.
Once operational, each TBM will work 24 hours a day, seven days a week, with up to 20 specialised workers inside at any one time. The machines are expected to progress around eight to 10 metres per day as they excavate rock and soil from the tunnel face.
SA Minister for Infrastructure and Transport Joe Szakacs said the milestone highlighted the scale of the project.
“The $15.4 billion T2D Project is not only the largest infrastructure project in South Australian history, but also the first road project in Australia to operate three large-scale TBMs concurrently.
“This historic first highlights the scale of what we are delivering.
“For motorists driving past these sites every day, this milestone is another visible sign that we are moving closer to a non-stop South Road.”
Federal Member for Adelaide Steve Georganas said the project would have a major impact on local roads.
“With the final cutterhead craned into place, this milestone marks another step forward on this game-changing infrastructure project.
“These tunnels will take thousands of cars off local roads, making it faster and safer for people travelling through our community.”
The Albanese and Malinauskas Labor Governments have each committed $7.7 billion towards the T2D project, which is expected to be delivered by 2031, if not before.
