TUNNEL BORING MACHINES On the original Scheme, tunnelling was achieved through drill and
TBM 1
blast and, in some cases, picks and shovels. During construction
TBM 1 will excavate the emergency, ventilation and cable
of Snowy 2.0 the bulk of the underground excavation will be
tunnel from the surface in Lobs Hole down to the power station
carried out by large tunnel boring machines, or TBMs. As part of
complex. From there, it will tunnel the inclined pressure shaft,
Snowy 2.0, there will be approximately 40km of tunnels dug, with
linking the headrace tunnel (the upper waterway tunnel) to the
the bulk of the excavation via the use of three TBMs.
large turbines within the power station.
Each TBM has been specifically designed to manage the various
Constructed in Germany by Herrenknecht AG, TBM 1 is a single
ground conditions they will encounter throughout construction.
shield, open mode machine designed to deal with hard rock
Some of the key drivers in the TBM designs have included
conditions. It is a very complex machine - it can operate downhill
the geology of the rock, the diameter of the tunnels and the
and then be converted to excavate uphill. At 205m in length
alignment and angle of the tunnel (e.g. the ability to operate at
(that’s the equivalent of two rugby league fields), it will be one of
steeper angles for the inclined pressure shaft).
the longest TBMs in operation around the globe. TBM 1 will have a diameter of around 11m (the same as a three-storey building) and will be able to excavate up to 30m of rock per day. TBM 1 is expected to start tunnelling early in 2021.
205m
10
