The big Tunnel Boring Machine (TBM) that will excavate the City Rail Link tunnels will start tunnel excavation from Mt Eden in April 2021.
It will take nine months for the TBM to complete the first of its two 1.6 kilometre-long journeys from Mt Eden to the Aotea Station in central Auckland to connect with the twin tunnels already built from Britomart Station and under Albert Street.
At peak operation the TBM can travel 32 metres a day. After its first underground drive to Aotea, the TBM will be returned to Mt Eden in sections and reassembled to excavate the second tunnel.
Timeline
The machine is undergoing further tests at the Mt Eden construction site
The Link Alliance will start tunnelling in April 2021
The TBM has three jobs underground: excavating the tunnels, removing dirt and rocks to the surface, and installing precast concrete panels that will line the tunnel walls
It will take about nine months to excavate each tunnel
At peak operation, the TBM can travel 32 metres a day
The TBM will work 24/7, operated by a crew of 12 underground
After its first underground drive to the Aotea Station in central Auckland, the TBM will be returned to Mt Eden in sections and reassembled again to excavate the second tunnel
Up to 1,500 tonnes of spoil can be excavated each day. Spoil will be transferred from the TBM by conveyor belt to the Mt Eden site and then transferred to disused quarries
Excavation of the second tunnel is planned to start in March 2022