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Source: ONE News -
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A giant boring machine which has been drilling a huge hole under Auckland for seven months has almost finished its task.
The custom-made machine is nearing the end of the three-kilometre tunnel under New Zealand's largest city - an ambitious engineering project to relocate an old sewer pipe.
The tunnel has been nicknamed Te Kaha, or the strength, and it has been creeping forward 18 millimetres a day since May.
The boring machine has been tunnelling its way under Auckland's Hobson Bay at record pace so a 90 year old sewer pipeline can be removed.
The tunnel will carrying a combination of waste water but during heavy rainfall it will also carry a fair percentage of stormwater.
But for now it's carrying materials, and workers, by train.
"It's on budget and it's slightly ahead of time," says Craig McIlroy from Watercare.
At its deepest point the tunnel runs 75 metres below the surface. It's 3.7 metres in diameter and when it's finished it will run three kilometres from end to end.
The project has involved removing 43,500 cubic metres of dirt and every sod is carried by the train, then lifted out to waiting trucks.
The whole operation hidden away by a huge green shed - not there for privacy, but insulation.
"The standard for noise at night time is a lot more strict than it is during day time so this does enable us to carry out a 24 hour operation," McIlroy says.
The original sewer was built in 1910 by a team of men but now the boring machine from Canada does most of the work - it even puts the concrete casing slabs in place as it moves.
Meanwhile a new pump station is being built above ground ready for the removal of the old pipeline in 2010.
The tunnel is designed to last hundreds of years at a total cost of $118 million.
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