Mangamuka Gorge opened on schedule

Kevin George (Fulton Hogan) and Jacqui Hori-Hoult (Waka Kotahi) at the site of the biggest of the now-repaired gorge slips. Photo / Michael Cunningham

As of six o'clock yesterday evening, SH1 once again ran unbroken from Cape Rēinga to Bluff for the first time in almost a year.

The highway, closed by a series of slips on July 17 last year, was scheduled to all vehicles, including trucks, at 6pm yesterday, with the completion of repairs including five retaining walls, dozens of concrete piles, realigning the highway, resealing sections of the road, and planting native shrubs on em embankments.

The cost had increased from an estimated $13.8 million to $16.2 million.

Jacqui Hori-Hoult (Waka Kotahi) said the project had been "complex and time-consuming," and involved working in tough conditions.

The largest slip had been the result of about 7000 cubic metres, 875 truckloads, of material falling away beneath the road, leaving its surface unsupported to the centre line. Contractors were still working in that area, putting the finishing touches on a 135m retaining wall, which had to be cut into the bank to restore it to two lanes.

One lane would remain closed over that 200m stretch of highway, with a traffic light system in place, for at least a month.

Hori-Hoult added that drivers would need to take care, as the road alignment had changed and shoulders had been reshaped.