What is a TBM?
A machine used to excavate tunnels by breaking the surrounding soil/earth/rock to create a large diameter tunnel.
How big is the TBM?
The TBM being used for this project is 4.5 metres in length, weighs approximately 30 tonnes and is 2.7 metres in diameter.
How fast does a TBM tunnel?
It is anticipated that the TBM will progress, on average, at a speed of about six metres per day in the expected conditions.
Why does the TBM need to operate 24 hours a day?
The TBM operates under a pressure system to move forward. This is facilitated by the use of a slurry (water and material mixture) to lubricate the pipes and reduce the friction. When tunneling stops, the slurry may harden and cause the pipes and TBM to be unable to be pushed forward.