• Published: Sunday, 29 September 2024

The South Australian Government and the T2D Alliance have signed the contract to purchase three tunnel boring machines (TBMs) from world-leading manufacturer Herrenknecht and revealed plans for two smaller TBMs also to come to excavate between the main tunnels.

The purchase of the three 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, wasting no time in getting ready for the start of main construction.

The historic purchase of the TBMs was confirmed at the Herrenknecht Headquarters in Schwanau, Germany.

Herrenknecht has delivered TBMs to countries around the world, including the United States, England, China, Singapore, Italy and Qatar, as well as Australia for projects such as the Sydney Metro and the North East Link and West Gate Tunnel Projects in Melbourne.

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.

Two smaller 4.1m diameter TBMs will also be ordered at a later date to construct the cross passages of the T2D tunnels.

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.

As promised, the T2D Alliance signed the contract to deliver South Australia’s biggest-ever infrastructure project in the third quarter of 2024, providing further certainty that the T2D project is on schedule.

Achieving this significant milestone on schedule provides more confidence for local industry to prepare for potential opportunities, with the State Government committed to maximising opportunities for South Australia businesses to ensure the T2D Project leaves a skills legacy.

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

Plans to procure three TBMs, instead of the two previously anticipated, were revealed in August 2024, meaning both northern and southern tunnels can be constructed concurrently.

The additional TBM gives a reasonable expectation that the project can not only be completed by the stated 2031 deadline – but even earlier.

The companies in the consortium have successfully delivered major tunnelling and infrastructure projects nationally and internally, including WestConnex, Sydney Metro and Southwest Tunnels and Station Excavation and Sydney Airport Rail Link, as well as the Trunk Road T2 Project in Hong Kong and High Speed 2 Link in the United Kingdom.

The T2D Project will support approximately 5,500 jobs per year during main construction, with 90 per cent of labour hours to be undertaken by South Australians.

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