Contractors use explosives to blast 'challenging' Awatere Valley Rd slip video

Photograph of a blast on Awatere Valley Rd, as contractors use explosives to try and clear the slip.
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Photograph of a blast on Awatere Valley Rd, as contractors use explosives to try and clear the slip.

Explosions in rural Marlborough are not common, so when one went off in the Awatere Valley the sound of the blast echoing off the hills was frightening, a resident says.

Contractors have been using charges to help clear a large slip blocking Awatere Valley Rd, which has cut nine families off from the coast behind a pile of rock and debris.

Kelly Pitts, along with her husband Hugo and their two young daughters, are the closest family to the slip, which is just 1 kilometre from their sheep farm Camden Station.

Marlborough District Council

Contractors clear slip in Marlborough with explosives.

The first time explosives were used a couple of weeks ago the family was not notified, so Kelly Pitts said it was quite frightening when it happened, as it caught them unaware doing work on the farm.

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Since then they had been kept informed, which was good as it meant they could avoid mustering sheep near the slip, or having the girls on their ponies when the explosives went off, she said.

Contractors set off 100 kilograms of explosives to blast away a large boulder, weighing more than 15 tonnes, on the ...
MARLBOROUGH DISTRICT COUNCIL

Contractors set off 100 kilograms of explosives to blast away a large boulder, weighing more than 15 tonnes, on the Awatere Valley Rd slip.

On Saturday, contractors used 100 kilograms of explosives to blast a rock weighing more than 15 tonnes from the slip face, a feat they repeated on Sunday to disintegrate another boulder hampering clearance efforts.

Pitts said the isolation was not too bad, as the family could still get to Hanmer Springs if they needed to, but her 5-year-old daughter had been off school since the earthquake on a "very, very long Christmas holiday".

"There are quite a few families cut off out here, so we manage to socialise among ourselves," she said.

A helicopter sluices a slip on Awatere Valley Rd.
SALLY SMITH

A helicopter sluices a slip on Awatere Valley Rd.

"Living up here you're used to not going to town regularly, but at least you could.

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"They're doing what they have to do and hopefully it works, because we're getting a bit over it."

Pitts said it was still possible to get over the slip, which the family had done once to attend a Christmas party for Awatere Valley residents at the closest farm on the other side.

"You can get over if you choose to hike up and around it, which we've done once with the 3 and 5-year-old, and they coped pretty well," she said.

"We were getting a little bit stark raving mad so we needed to get out and socialise."

Supplies were still getting in to the families trapped behind the slip by helicopter, but Pitts said the family was starting to run a bit low, as they needed heavier items, such as farm supplies and pet food.

At first they had not requested these, because of the limited space on the helicopter, but they would need them soon as their supplies were running low, she said.

Marlborough Roads journey manager Steve Murrin said the slip was incredibly challenging to clear, not because of its size, which he estimated at 3000 cubic metres, but because of the location and steep terrain.

Murrin said he was aware of the use of explosives elsewhere around the country, but this was the first time he had seen them used in Marlborough to clear a slip.

"One of our geotechnical engineers, who is very experienced and worked in Christchurch on the Port Hills and Sumner rock falls, says this slip is the most technically challenging he has seen," he said.

Two helicopters had been flying for up to five hours a day, trailing monsoon buckets to dislodge debris on the slip face by sluicing it with water.

Abseilers from engineering company Geovert were approaching the slip from the top, prying off loose rocks with crow bars, and monitoring the stability of the slip face, which had also been attacked by a remote-controlled digger.

Now that the two rocks had been removed, Murrin said work with the remote-controlled digger would continue from the coastal side of the slip and another excavator was being brought in from the Molesworth end.

It was difficult to know when the road would re-open because of the challenging nature of the work, but it should be possible to give a prediction later in the week, he said.

"It gives an indication of the challenges ahead of us to restore State Highway 1 down to Kaikoura."

Marlborough Civil Defence was flying supplies into remote farms cut off by the slip every week, and other residents who needed assistance were encouraged to contact the Marlborough District Council.

 - The Marlborough Express

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