South Australia's biggest ever infrastructure project, the $15.4 billion River Torrens to Darlington works to create a Non Stop South Road, is hitting a major milestone with the first of three 300-tonne Tunnel Boring Machine cutterheads being lifted into place.
In a carefully coordinated operation, a 500-tonne gantry crane will safely lower the cutterhead into the 20-metres-deep Southern Precinct launch box at Clovelly Park.
The Australian and South Australian governments have each committed $7.7 billion towards the T2D project.
Around 120,000 cubic metres of material weighing more than 343,000 tonnes has already been excavated in preparation for this milestone to form the TBM launch box, which measures 120m x 50m x 20m.
The first and second TBMs are being assembled alongside each other at the Southern Precinct. They will soon be tasked with carving out the twin Southern Tunnels, excavating through soil and rock, known as spoil, on the 4.5-kilometre journey towards Glandore and Black Forest.
Meanwhile, all components for the third TBM, which will dig both of the 2.2 kilometre-long Northern Tunnels, have now arrived in South Australia.
Once the first cutterhead has been attached to the front of the TBM, other major parts of the machine will then be assembled, with the completed TBM to undergo final testing and commissioning before tunnelling begins.
Tunnelling is expected to commence in the second half of 2026. Once operational, each of the mega machines will operate 24-hours a day, seven days a week, progressing approximately 8-10 metres per day, with up to 20 specialised workers inside at any one time.
The tunnelling team on the T2D Project has been involved in some of the world's biggest and most complex tunnel projects, including WestConnex and Sydney Metro in Australia, as well as Northern Line Extension in London and the Trunk Road T2 Project in Hong Kong.
The T2D Project is bringing these tunnelling experts together with our local workers to share their knowledge and ensure the Project will leave a skills legacy for South Australia.
Each TBM will be approximately 100m in length and 15m in diameter, roughly the height of the Thebarton Theatre or the goalposts at Adelaide Oval, and weigh approximately 3,500 tonnes.
The use of three TBMs will allow both the Northern and Southern Tunnels to be constructed concurrently, for the Project to be delivered by 2031, if not before.
Quotes attributable to the Premier of South Australia Peter Malinauskas:
"This is a major milestone for the biggest infrastructure project in our state's history.
"The first of three huge cutterheads being lowered into place today gives us a real sense of the monumental scale of this project to create a Non Stop South Road.
"As South Australians continue to drive along South Road each day, all this work will be taking place just metres away. Each of these massive Tunnel Boring Machines will be around 100 metres long with a diameter of 15 metres - the height of Thebarton Theatre or the goalposts at Adelaide Oval.
"Once completed, this project will allow the north-south corridor to finally flow, letting South Australians bypass 21 sets of traffic lights on their commute and saving them hours each week."
Quotes attributable to Federal Infrastructure, Transport, Regional Development and Local Government Minister Catherine King:
"River Torrens To Darlington is South Australia's biggest ever road project, and the final piece of the road corridor that will link Adelaide's north to the south.
"The new underground tunnels will allow cars to skip 21 sets of traffic lights, and shave almost 40 minutes off some daily commutes.
"The Australian Government is proud to be working with the South Australian Government to deliver this game-changing infrastructure for Adelaide."
Quotes attributable to SA Minister for Infrastructure and Transport Joe Szakacs:
"This is one of the biggest milestones we've seen so far on this Project, and it marks the moment tunnelling starts to become a reality.
"The assembly of the first Tunnel Boring Machine for the $15.4 billion T2D Project is progressing well, with this milestone marking another step forward.
"Lifting the 300-tonne cutterhead into place is a monumental undertaking requiring careful planning and execution.
"The T2D Project is the largest infrastructure project in our state's history and will complete a 78km non-stop, traffic light-free motorway between Gawler and Old Noarlunga."
Quotes attributable to Federal Member for Boothby Louise Miller-Frost:
"The Torrens to Darlington project is right here in Boothby, and people can see the work taking shape every day. This milestone shows we're getting on with the job of delivering something better at the end of it.
"These tunnels will take thousands of cars off local roads and out of traffic lights, making it faster and safer for people travelling through our community."
