By rosebell
The two tunnel boring machines (TBMs) used to construct Australia’s North East Link road tunnels have been dismantled and removed from the Melbourne project site.
The 15.6m-diameter Herrenknecht machines, TBM Zelda and TBM Gillian, were launched in August 2024 to excavate the twin 5.3km tunnels. Zelda completed its drive in May 2026, followed by Gillian in July 2026.
During excavation, the machines removed approximately five million tonnes of rock and soil and installed more than 43,000 precast concrete tunnel segments. Following breakthrough, the TBMs were dismantled, with components either recycled or returned to Herrenknecht for potential reuse.
TBM components recycled into steel reinforcement
TBM Zelda’s cutterhead, weighing more than 380 tonnes, was lifted from the site and dismantled. Its centre was cut into smaller pieces and transported to a mill for recycling.
At the mill, the steel was processed into smaller sections before being melted down and reshaped into steel reinforcement for use on other projects in Melbourne.
Tunnel fit-out moves forward
The remaining 1.2km of the overall 6.5km tunnel alignment was constructed using roadheaders and top-down construction methods. The completed road tunnels will provide four lanes in each direction between Manningham and Bulleen.
With both TBMs removed from the tunnelling area, fit-out works are progressing. The remaining activities include constructing the internal roadway using approximately 700,000 tonnes of reinforced concrete, installing around 3,300km of cabling, completing 51 emergency access passages between the tunnels, and finishing the tunnel entry and exit ramps at Manningham and Yallambie.
The project is being delivered by the Spark consortium, comprising Webuild, GS Engineering and Construction, CPB Contractors, China Construction Oceania, Ventia, Capella Capital, John Laing Investments, DIF and Pacific Partnerships.
The North East Link tunnels are scheduled for completion in 2028. They will connect the M80 Ring Road with the upgraded Eastern Freeway, improving road connections across Melbourne’s north-east.
