Second Waterview motorway tunnel reaches quarter mark

The Waterview Connection tunnel project has made good progress over the past months. Photo / Nick Reed

The tunnel boring machine Alice is now a quarter of the way into drilling the second motorway tunnel of the Waterview Connection.

The machine has now excavated 630m of the 2.4km second tunnel, and has passed under Great North Rd, 22m underground.

New Zealand Transport Agency highways manager Brett Gliddon said the work was on track to break through at Owairaka in mid-Spring.

Alice, the world's 10th largest tunnel boring machine, began the second tunnel after a complex operation to turn the machine around.

The cutter head was turned first to excavate the first 250m to make room for the rest of the machine.

"Worldwide, very few TBMs are turned to complete a second run underground and the project's extraordinary innovation to achieve this manoeuvre with just millimetres to spare at times is now fully complete. All the support facilities for Alice are in place and fully functioning," Mr Gliddon said.

The first of the two three-lane tunnels was completed in September, and work has begun on 17 cross passages that will connect the two.

The tunnels will connect the Northwestern and Southwestern motorways to connect the Western Ring Route. The project is expected to be complete in early 2017.