TBM Boring 24/7

CRL Link Alliance Mt Eden Station Drone Footage July 2021

The final piece of City Rail Link’s (CRL) Tunnel Boring Machine (TBM), Dame Whina Cooper, was put in place earlier this month allowing the big underground factory to operate at full capacity on its transformational journey below Auckland.

Fitting a conveyor belt to the TBM to continually remove spoil excavated underground allowed the project to shift tunnelling up a gear to a 24-hour-seven-days-a-week operation from working previously 24 hours-five-days-a-week.

“As with any machine, Dame Whina Cooper has had a careful and steady start. Being able to run 24/7 means we’re now ramping up even more to get the very best from our TBM,” says Francois Dudouit, Project Director for CRL’s Link Alliance.   

Tunnel spoil, conditioned by the TBM into a paste, is carried along the conveyor belt to a purpose built “muck” shed at the project’s Mt Eden site. This spoil will then be loaded on to trucks and taken to various disposal sites around Auckland and north Waikato.

A team of 12, below and above ground, operates the TBM on its 24/7 schedule. Three teams rotate shifts every 12 hours.

“Progress is good - we’re all aware of CRL’s importance and the big difference we are making to the city’s future,” Dudouit says.      

Already, 11,000 tonnes of spoil and 145 metres have been excavated since tunnelling began at Mt Eden in May. Removing spoil is one of the three main functions the TBM designed for Auckland’s subterranean conditions has, alongside digging the tunnels and lining them with concrete.

People can follow Dame Whina Cooper’s progress at digCRL.co.nz, updated fortnightly.