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Tunnelling continues at Snowy Hydro

Snowy Hydro 2.0

After finishing the 2.9km emergency cable and ventilation tunnel, tunnel boring machine (TBM) Kristen has been modified for its next critical role at Snowy Hydro 2.0.

The inclined pressure shaft (IPS) will be a unique and technically challenging feat, according to the project team.

It is a steep, 1.6km, 10m diameter shaft and forms part of the waterway and will connect the headrace tunnel with the underground power station.

“It means we can do less steel lining, we can move power stations closer to the surface which is what we’ve done here and construct an inclined pressure shaft with a tunnel boring machine which all makes it safer, quicker and the quality a lot better,” Snowy 2.0 project director Dave Evans said.

TBM manufacturer Herrenknecht has allowed TBM Kristen to be modified to safely tunnel uphill.

The machine’s working platforms, equipment and operator’s cabins all pivot to remain horizontal and the walkways become steps and ladderways.

A screw conveyor will move excavated rock from the cutterhead.

This feeds into a sandwich conveyor that has face-to-face rubber belts to hold the material so it can be transported down the steep slope without spillage.

The IPS is on a 47 per cent incline so a monorail is being installed to transport workers and there is a rack and pinion system for multi-service vehicle access including segment delivery up the steep slope to the TBM.

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