Protective barrier going up on SH6

23:18, Aug 20 2014
Diana Falls
ROCK BLOCK: Contractors work to winch a six-metre high, 720kg post which will be used to build a rockfall barrier fence at the Diana Falls slip site between Makarora and Haast.

Work to install a "complex rockfall protective system" which could stop a 16-tonne boulder rolling onto State Highway 6 has begun at the Diana Falls slip site.

The project, the largest of its kind in Australasia, includes building three rockfall barrier fences which need five six-metre high posts, weighing 720kg each.

The first posts were lifted onto the site, between Makarora and Haast, and put into place on Monday.

New Zealand Transport Agency senior network manager Mark Pinner said when the three rockfall barrier fences were completed at the end of next month, there would be more than 30 tonnes of steel mesh on the hillside in what would be the most complex rockfall protection system ever to be installed in Australasia.

"Each fence will have the capacity to stop a boulder weighing up to 16 tonnes which is travelling down the hillside at a speed in excess of 90kmh."

Posts for the second fence, being built about 150 metres up the slip face, were expected to be installed within the next week.

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Work would then begin to hang the five tonnes of high tensile steel mesh that would be draped between the posts across the slip.

When the work was competed it would allow the road to open to two-way traffic with no closing restrictions, in time for the start of the busy summer tourist season.

The stretch of highway has been marred with closures and large rockfalls, including the Diana Falls slip on September 10.

Canadian couple Connor Hayes, 25, of Ottawa, and his girlfriend, Joanna Lam, 24, of Ontario, were killed during a West Coast storm on the night of the slip after their campervan was swept away in a second slip 800m away.

The Southland Times