Snowy 2.0 - Tantangara Transition Tunnel Breakthrough

Webuild and Clough as part of Future Generation Joint Venture, the principal contractor for Snowy Hydro Limited’s Snowy 2.0 Project, are pleased to announce the breakthrough at the Tantangara transition tunnel.

The breakthrough was successfully achieved in early October, connecting the water intake at the upper reservoir to the gate shaft.

This is a significant milestone for the project, which was achieved with the highest safety outcomes.

The drill and blast team at Tantangara meticulously planned and prepared for this milestone. The successful execution involved process optimisations including increasing the excavation length, and excavating the tunnel from both sides, to ensure the breakthrough created a tunnel connection that seamlessly fit together like two pieces of a puzzle.

Through the use of traditional drill and blast techniques, the team removed over 14,700 cubic metres of material – the equivalent volume of approximately six Olympic-sized swimming pools.

They also sprayed 13,000 cubic metres of shotcrete and installed 3,200 rock bolts to support the rock face.

Once complete, the tunnel will deliver water to the gate shaft, then to the headrace tunnel, all the way to the power station at Lobs Hole.

The 62-metre-deep Tantangara gate shaft is one of the key structures in the overall Tantangara intake system which functions to stop and start the flow of water into the headrace tunnel and power station for maintenance purposes or in the case of an emergency.