Te Ara o Te Ata – the NZ$260 million Mt Messenger Bypass is a new 6km route that avoids the existing steep, narrow and winding route over Mt Messenger on State Highway 3 in North Taranaki. The Messenger By-Pass entails the construction of two bridges and the construction of a tunnel to avoid a notorious stretch of road.
The cableway project, delivered by Mt Messenger Alliance (Waka Kotahi NZ Transport Agency, Downer, HEB Construction, Tonkin and Taylor and WSP), won the Project of the Year Award at the annual Crane Association of New Zealand’s awards.
Due to land access issues, the project required the installation of a 1.1km cableway, the first of its kind in the Southern Hemisphere. The cableway is designed to feed the northern side of the project with all of its plant and materials and to remove anything that needs to come out.
Waka Kotahi Owner Interface Manager Chris Nally said the $8 million cableway – which was being imported from Austria – would enable access to critical components of the project.
“One being the tunnel and one being a large fill, right, about 600,000 cubic metres of fill has to be positioned on the north side of where the tunnel’s going,” he said.
“This cableway gives us the opportunity to access into that which at the moment is a deep valley without having to cut big tracks through the environment.”
Independent Cranes was contracted in the early stages of the project to help in the construction of the cableway. The Taranaki-based, family owned small business is only in its second year of trading. Ben and Gemma Jones and their team of experienced professional operators, riggers, dogman and rope access technicians are proud to have worked on the project and to have received the Project of the Year Award at the annual Crane Association of New Zealand’s awards.
Ben said the project was “massive”.
“The cableway has a 20 tonne maximum carrying load anywhere on the northern side of the project. The construction process was a gigantic task in itself, and included helicoptering in mini excavators into the bush, building the anchors, flying all the concrete in via helicopter and flying all the steel. The tower construction, which won the Project of the Year Award, was on top of a ridge line where there was very little room,” said Ben.
Parts for the cableway came from Brazil, the legs were built locally by DIALOG Fitzroy Engineering, and the whole cableway was leased from Doppelmayr Australasia.
Independent Cranes was tasked with the construction of cableway, a task which Ben says required detailed planning.
“We went through three-month planning process during which time we addressed the issues relating to extremely limited access, the small footprint we were able to operate on, the ground conditions, the weather, the sheer nature of the project was intimidating.
“The construction of the towers had to be millimetre perfect, and they were anchored at a 10 degree angle. Because the ropes are 1.1km in length, if we were out millimetre out at the head, this would translate to being metres out at the other end. We lifted the towers in halves and each lift was 26t, 52t in total,” said Ben.
To do the work, Independent Cranes dry-hired a 280t capacity Liebherr LR 1280 with 52 metres of main boom and full counterweight from Smith Cranes and Construction.
“We assembled Liebherr on site and we had just enough room to put it together, literally we were 300 mms of not being able to put the crane together.
“We then walked the crane into position and we stick-built each half of the tower on the ground. We then put on rolling blocks and a spreader bar for the top of the lift, so we could lean the tower.
“We stood the eastern side of the tower first and put it onto its feet and we suspended that off a specially-designed ground anchor and set that to a 10 degree lean.
“We then removed the crane and spun around and went through exactly the same process to build the second half. We picked that up and mirrored the first lift and lent that in at 10 degrees with the crane and bolted it together.
“Each tower was flat when we picked them up which meant we were lifting at a radius of 36 metres and when we were installing them we were lifting at a radius of 10 metres on the eastern side and 12 metres on the western side.
“We ran the Liebherr LR 1280 its standard configuration with 52 metres of main boom. We deliberately ran with only the main hook as weight was absolutely critical. The cane was at 98 per cent of its charts during some of the lifts,” said Ben.
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Ben explains more about the construction process and how long everything took.
“The tower build took two days. We spent day constructing the eastern side and about four hours to stand it. And then three days later, we constructed and stood the western side and bolted it all together.
“That saw the tower standing and then we were on site for another 10 days adding platforms and accessories to the tower. All the planning and the detail we went into paid off with every bolt able to be pushed through and into place by hand,” said Ben.