Source: New Zealand Transport Agency
Tunnelling has begun this week at the Te Ara o Te Ata – Mt Messenger Bypass project in North Taranaki.
Following an early morning blessing from mana whenua and iwi partner Ngāti Tama, the first cut was made by a 110-tonne road header machine that will excavate the project’s 235-metre tunnel.
Road headers have boom-mounted telescopic cutting heads, making them ideal for diverse geological conditions. A shovel plate at the front of the road header collects the excavated rock and soil, which is then conveyed via a belt to dump trucks at the back of the machine.
The 235-metre tunnel will be an important part of the Bypass project, contributing to a much more resilient stretch of State Highway 3.
NZ Transport Agency Waka Kotahi Project Manager Caleb Perry says having the road header onsite is really exciting for the project.
“We’ll start to see some progress with the road header excavating up to 3 metres every day.
“The tunnel will be cut in two stages, with the upper portion (top heading) first, followed by the bottom section (bench). At regular intervals, excavation will be paused and ‘shotcrete’ – a sprayed-on concrete – will be applied to the crown and walls to line and support the structure.
“The design and construction of the tunnel are similar to the Northern Gateway Tunnel in Auckland and the tunnel will be large enough to accommodate loads up to and including house removals – this isn’t something that can currently be accommodated on the steep, narrow winding stretch of SH3.”
At this stage, the excavation is expected to be completed later this year.
“The Mt Messenger Bypass will make this stretch of SH3 much more resilient, and safer for all motorists, providing a secure connection through North Taranaki, especially for freight.
“The finished tunnel will incorporate cultural elements acknowledging Ngāti Tama tūpuna, the traditional guardians of the northern gateway to Taranaki.”
Backgound
The Mt Messenger project has named this road header ‘Hinetūparimaunga’ – the atua of mountains and cliffs.
A design on the side of the roadheader depicts Hinetūparimaunga with outstretched limbs supporting the roof, walls and floor of the underground space. A yellow background represents the light that will flood into the tunnel upon its completion.
Images: The roadheader and initial progress