Mountains to Sea cycle trail section on Mangapurua Track reopens after major slip

The Mangapurua Track slip viewed from a helicopter.

The Mangapurua Track on the Mountains to Sea cycle trail has reopened to riders with a temporary path to avoid a large rock that must be removed.

After a major slip last week, the Department of Conservation (DOC) closed the track leading to the Bridge to Nowhere due to safety concerns.

The fragility of the soft papa rock in the area is a slip hazard, causing the track to be closed over winter and after severe weather.

“You can’t really tell when it’s going to fracture. It can be wind, it can be rain, it can be heat,” DOC senior ranger Jim Campbell said.

The area that slipped has been stabilised by abseilers who scaled the face to remove loose rocks.

“Above the track is safe now,” Campbell said.

The track has reopened to the public but work will continue.

“We’ve put a temporary path around the big rock that’s sitting in the middle of the track. So that’s made it passable.

“It is a really big rock. I don’t know how many tonnes it would weigh, but it’s a lot.”

Abseilers scaled the rock to prevent debris fall at the Mangapurua Track slip.

A decision was still to be made on the best way to remove the rock.

“There could be explosives, which is complicated in a health and safety way, there is some expanding gels that they use to crack the rock,” Campbell said.

“There are various ideas around hydraulic jacks and winches, and porter powers, to try to push the rock over, and there is an idea around an air bladder, which the fire service use for shifting things. It’s not something we can shift with a small digger.”

It is expected to be another week until the rock can be removed.

Riders are urged to use caution and walk their bikes on the temporary section of track.

Olivia Reid is a multimedia journalist based in Whanganui.