On 29/09/2024 the South Australian Government and the T2D Alliance have formally sealed a contract to purchase three initial TBMs from world-leading manufacturer Herrenknecht.

Infrastructure and Transport Minister Tom Koutsantonis also confirmed plans to purchase two additional, smaller TBMs – with another likely to follow – to carry out excavation work between the main tunnels. The total cost of all TBMs is expected to be around EUR111.94 million (AUD180 million).

The purchase of the three initial TBMs comes just two weeks after the main construction contract was officially signed by the consortium of John Holland, Bouygues Construction, Arcadis Australia, Jacobs and Ventia – with the Government wasting no time in getting ready for the start of main construction.

The TBM components will be manufactured in Germany and China, before being assembled and factory assurance tested in China and then delivered to Adelaide. The first of three TBMs is expected to arrive in late 2025.

Once in Adelaide, it will take time to assemble and commission the TBMs before they can start tunnelling works.

The TBMs being used to construct the T2D tunnel will be approximately 100m in length and 15m in diameter - roughly the height of the Thebarton Theatre or Edwardstown Bunnings.

New, smaller 4.1m-diameter TBMs will also be ordered to construct the cross passages of the T2D tunnels – saving time and endeavour on conventional construction methods. These cross passages will house equipment which support the day-to-day operations of the tunnels. They will also form part of the safety systems in the tunnels as they provide a means of emergency egress in the event of a major incident in one of the tunnels.

The successful consortium has confirmed it can deliver the T2D Project on budget, delivering significant travel, economic and community benefits for South Australians.

The procurement of three initial TBMs for the major tunnelling work means both northern and southern tunnels can be constructed concurrently - giving a reasonable expectation that the project can not only be completed by the stated 2031 deadline, but even earlier.

Main construction works are proposed to start in 2025, with TBM works for the southern tunnels planned to begin in the second half of 2026.

Click here for the  tunnelbuilder archive and visit https://www.t2d.sa.gov.au/ and https://www.premier.sa.gov.au/.  40/24.