A 15-week rock stabilisation programme on the Nevis Bluff on the outskirts of Queenstown has been completed.
The Aspiring Highways team, working for Waka Kotahi NZ Transport Agency, has been working on the “Yates Feature” for more than a year with this latest programme finishing in recent weeks.
The stabilisation work follows an increase in movement in late 2021 and initial work in early 2022 on a large rock mass weighing more than 12,600 tonnes.
Robert Choveaux, Senior Network Manager, Central Otago for Waka Kotahi, says the works highlight the ongoing safety issues in the area.
“The crews have worked tremendously hard in what have been challenging conditions to secure this rock face and the roading network below.
“We cannot underestimate their dedication and skill – working 160 metres off the ground, in restrictive health and safety gear, on rig attachments, surrounded by dust and wind. While they may get fantastic views – their working conditions are not easy.”
Including both stages, the team has been working on the Yates Feature for 29 weeks. They have drilled just over 2000 metres, installed 182 rock bolts and mesh to prevent weathered and fractured rock falling out and completed bolt tensioning.
The works have rolled into the usual autumn/pre-winter checks.
Mr Choveaux says it is part of Waka Kotahi’s ongoing commitment to provide a safe, accessible highway network.
The Nevis Bluff is about half-way between Cromwell and Queenstown – 25 minutes from Cromwell, 35 minutes from Queenstown, above the Kawarau River.
Josh Barrett and Adam Sanders preparing to drill a hole high up on the Yates Feature of the Nevis Bluff. Photo credit: Wayo Carson
The Yates Feature
The Yates Feature is located at the Queenstown end of the Nevis Bluff and is about 130 – 160m above State Highway 6.
The rock feature is approximately 4,200 cubic metres, weighing more than 12,600 tonnes, 30m high and 20m wide.
It has been monitored since 2001 but showed just small amounts of movement up until late in 2021, when it started to increase. The physical properties of the schist rock make it susceptible to ongoing weathering through winter freeze/thaw conditions and drying out due to hot and windy conditions.
