SH3 rockfall prevention work begins


A 1600 sq m steel net will be anchored into a section of the Mangaotaki Bluffs above State Highway 3 (SH3) to prevent rock falls in the area, the NZ Transport Agency says.

The $2.5 million safety project will start on Monday September 1, with a crew of abseilers clearing the site so contractors can start drilling anchors into the bluff to secure the steel net.

The work, south of Piopio in the King country, was expected to be complete by early December, NZ Transport Agency’s regional performance manager Karen Boyt said.

The stretch of highway had been down to one lane with a temporary barrier to contain rocks following a fatal rockfall in March.

Current stop/ go traffic management will remain in place while contractors complete the work.

Ms Boyt said the steel net was a long term solution to rock stability at the site.

“Geotechnical specialists worked their way through a detailed inspection and rock scaling (removal of small rocks) process earlier this year to gain a better understanding of what work was needed to stabilise the cliff face,” she said.

“Since then we have removed larger rocks by blasting at the site but our investigations show that the steel net is the best long-term safety solution.”

Ms Boyt said a crew of abseilers would begin the project by clearing loose material off the rockface from Monday, however the majority of work to anchor the net would be completed by workers using drill rigs attached to two cranes.

“When the project is complete, the steel net will be secured to the bluff by 500 anchors, which will dramatically reduce the risk and impact of rock falls in the future,” she said.

The Transport Agency appreciates motorists continued co-operation and patience while the work continues.

The facts:

  • 1600 m2 – amount of steel net to be used
  • 500 – number of anchors
  • 6-8 - number of specialist abseilers/drilling contractors to carry out work
  • 60m – length of SH3 to be protected by the net
  • $2.5m – cost of project

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For more information please contact:

Natalie Dixon
Waikato & Bay of Plenty Media Manager

T: 07 928 7908
M: 021 928 413