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What is a tunnel boring machine (TBM)?

A machine used to excavate tunnels by breaking the surrounding soil/earth/rock to create a large diameter tunnel. Pipe is then laid behind the tunnel as it is excavated underground.

How big is the TBM?

The TBM being used for this project is 7.5 metres in length, weighs approximately 15 tonnes and is 1.5 metres in diameter.

How fast does a TBM tunnel?

It is anticipated that the TBM will progress, on average, at a speed of about ten metres per day in the expected conditions. Please note, timelines are estimates and may change on construction and soil 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 friction. When tunneling stops, the slurry may harden and cause the TBM to be unable to be pushed forward. As a result, 24/7 operations are required during the tunnel period of construction. 24/7 work will occur at worksites #2, #3, #5, #7, #8 and #11.

What is a slurry separation machine?

A slurry separation machine is a large piece of equipment (approximately two stories tall) used to mange soil removal. The machine separates the solids from slurry, so that the water can be recycled back to the TBM. The machine operates 24-hours-a-day while the TBM is tunneling. Noise mitigation panels will be used to dampen the noise generated by the machine. This machine will be on site at worksites #2, #3, #5, #7, #8 and #11​.​

​Example of a micro-tunnel boring machine (TBM) used during construction

Example of a slurry separation machine used
onsite during tunneli​​​ng activities