Final TBM journey nears

The Dame Whina Cooper tunnel boring machine (TBM) had its second breakthrough at Karanga a Hape Station (Karangahape) during July - slightly ahead of schedule. The next and final stop for the TBM is Te Wai Horotiu Station (Aotea) in midtown, with a breakthrough expected to happen this September.

To reach the breakthrough point, the TBM travelled 900m, placed 526 concrete tunnel lining segment rings and removed 74,000 tonnes of spoil.

“Given everything that’s happened over the last two years, it’s particularly pleasing to see us meet our objectives on this section of the project,” CRL Chief Executive Dr Sean Sweeney said.

The TBM team have begun pushing the machine forward through the 230-metre tunnel cavern, from Mercury Lane to the Beresford Square entrance. In some places, there is less than one centimetre of clearance between the machine and the tunnel walls – requiring a complete team effort to ensure the smooth move.

The TBM is now near its relaunch position underneath Beresford Square – almost ready to set off for its final drive to Te Wai Horotiu Station (Aotea).