SH1 over Mangamukas in Far North to finally reopen before end of the year

Work on SH1 through the Mangamukas in the Far North is progressing and it is hoped the road will reopen towards the end of the year, much to the delight of Kaitāia Business Association chairman Josh Kirby.

News that State Highway 1 over the Mangamukas should be open by the end of the year is a huge win for the area’s business community and residents, Kaitāia Business Association chairman Josh Kirby says.

SH1 has been closed over the Mangamukas for almost two years due to numerous slips caused by a series of adverse weather events. The closure has meant a lengthy detour through SH10.

It has also had an impact on the area’s economic situation, with the delays meaning extra costs to get goods to and from the Far North.

Kirby said Steve Mutton, director of regional relationships for NZ Transport Agency Waka Kotahi, spoke to the association at the end of last month to give an update on how work was progressing, and an expected date for the vital road link to finally reopen.

“[Mutton] assured us that despite the extensive work required, the project is on track for a late 2024 completion. This would be a huge win for the Far North, allowing us to head into the Christmas season with a fully open SH1,” he said.

“It would mean a great deal to the wider Te Hiku community, to see SH1 over the Mangamuka reopened in time for Christmas.”

Kirby said the Kaitāia business district in particular would benefit greatly from having its main arterial route open, and could once again establish itself as the gateway to the Far North.

The giant piling rig being used to repair the road over the Mangamukas.

“The Kaitāia Business Association will continue to seek regular updates on progress and will communicate this to our BID membership as frequently as possible. It would be nice to feel connected to the rest of the country in time for Christmas,” he said.

NZTA said an average of 17 companies worked on the site daily, with a remarkable 82 per cent utilising local workforce.

“A huge shout-out to those locals up there doing the mahi,” it said.

The road has been closed since August 2022 and had been expected to take six weeks to repair, before more foul weather caused further slips. The lengthy closure and subsequent economic and social impacts have brought calls for a new route around the Mangamukas for SH1 that was not as prone to slips.

NZTA is using a massive piling rig on the Mangamuka Gorge work.

The Liebherr LB24 is the largest piling rig on site, and it’s not your average drill. The rig weighs more than 78 tonnes, is 24m tall, and can move at a top speed of 1.45km/h, which is extremely quick given its size. It’s perfect for drilling the 1m-diameter piles needed, to a depth of up to 50m.

Due to the unstable terrain, NZTA had to do a lot of enabling works to make sure the ground was able to hold the weight of the rig, and that the holes were drilled straight up and down. This included using a smaller rig to drill 747 temporary piles, and building specific work platforms.

People can keep up to date with the work through the gorge by subscribing to NZTA’s monthly Mangamuka Gorge e-newsletter at https://www.nzta.govt.nz/.../far-north-state-highway.../