Nancy ready to begin drilling McConnell Dowell's northern tunnel

McConnell Dowell built the 3km tunnel replacing Hobson Bay sewer. Photo / Paul Estcourt

McConnell Dowell Constructors is drilling an underground tunnel north of Auckland, from the Watercare Pump Station off Millwater Parkway at Orewa to subdivisions north of Grand Drive.

The machine arrived this month and drilling was to start immediately.

Michael Buckland, McConnell Dowell construction manager, said the business would lay 3.15km of wastewater pipeline for Watercare using microtunnelling trenchless technology.

The wastewater will flow through the pipeline via gravity offering big advantages during construction and operation in terms of safety and environmental and community impact, Buckland said.

Children at Silverdale Primary School named the Millwater tunnel boring machine Nancy after the New Zealand-born World War II hero Nancy Wake. According to tunnelling tradition throughout the world, a tunnel boring machine cannot start work until it is given a name. Just like Alice at Waterview, the new Millwater machine was to be given a woman's name as a sign of good luck for the project. Local primary school children from Kingsway, Silverdale and Orewa Primary Schools were all given the opportunity to enter a competition to name the machine, researching famous New Zealand women in history for inspiration.

The company also bored wastewater micro tunnels for the $83.5 million Christchurch Ocean Outfall, the largest civil engineering project undertaken by the Christchurch City Council before the Canterbury earthquakes. The 3km long tunnel is one of the longest outfalls in New Zealand and required the longest micro tunnel drive of its type in the Southern Hemisphere at that time.

The company is now finishing the replacement of twin bridges at Kurow.

McConnell Dowell is also part of the Well-Connected Alliance on the Waterview Connection project.

McConnell Dowell is not part of McConnell Group, which owns Hawkins Construction, although they had the same original co-founder, the late Buck McConnell.

The business has built many big tunnels in the past few years - Auckland's Hobson Bay tunnel and the Rosedale and Dunedin ocean outfall tunnels.

The company plans to bid for Auckland's $2.4 billion City Rail Link and a spokesman said the business had learned a lot from the Singapore mass rapid transit project, which is still being built.