Retrieval of tunnel boring machines Betty and Dorothy is now underway following the completion of their work on part of the Sydney Metro West tunnels.
The two machines carved out the new tunnels from Sydney Olympic Park through Parramatta, finishing their journeys with breakthroughs at Westmead in September and October.
Their nine-kilometre drive was also a first for Australia, completed using autonomous tunnel boring machines equipped with artificial intelligence software that can steer, operate and monitor the equipment without manual control.
Work has now begun to dismantle and lift the 1200-tonne machines to the surface. Each TBM is taken apart underground and removed piece by piece using a 750-tonne mobile crane.
Major components, including the 100-tonne cutterheads and 110-tonne main drives, are lifted out with the mobile crane, while smaller sections are brought up over multiple loads using the gantry crane.
The machines are carefully taken apart, moved through the crossover cavern to the station box and lifted to the surface in stages. The full retrieval process is expected to take about seven weeks.
Key components such as the main drives will be refurbished and reused on future tunnel boring projects, while the remaining parts will be recycled.
