Students at Snells Beach School checked out Piper as it began its slow journey to the ocean in February. Piper advanced at about 35mm a minute.
The construction team working on the Snells/Algies wastewater pipe upgrade have broken the “direct pipe” world record for the longest single drive by a microtunnel boring machine.
The machine, christened “Piper” by students at Snells Beach School, successfully bored a tunnel more than two kilometre long, from private farmland in Algies Bay to reach the ocean, just south of Martins Bay.
In direct pipe drilling, the drill head is attached to the end of the pipeline and pulls the pipeline along with it as the drill head advances through the earth. Debris from the drilling is delivered back to the surface via the lengthening pipe.
The Herrenknecht tunnelling machine, operated by contractor McConnell Dowell, bored through challenging geological conditions and navigated a curved alignment to create a tunnel 2021 metres long.
“This record achievement demonstrates the depth of skill and experience we have in our tunnelling teams,” McConnell Dowell project manager Brent Whiting said.
The effort surpassed the previous world record by 92 metres, which was achieved in the construction of a tunnel at Army Bay, on the Whangaparaoa Peninsula. The Army Bay tunnel was also constructed by McConnell Dowell. The 1.9km tunnel at Army Bay beat an earlier record held by a tunnel in Texas.
McConnell Dowell is continuing to dig an open trench along Mahurangi East Road, from Algies Bay to Dawson Road, to advance the pipeline as far as Snells Beach. It hopes to reach Dawson Road in about six weeks. The entire length of the pipe will be about 6.5km.
The new pipe is designed to cope with population growth and replace an existing wastewater pipe along Mahurangi East Road and an ageing outfall pipe at the end of the Mahurangi Peninsula.