Snowy Hydro’s Snowy 2.0 precast factory in Cooma has achieved an impressive milestone, with manufacturing completed for all concrete segments that will line the dry access tunnels.
More than 25,000 of these seven-tonne segments have been produced at the Polo Flat factory, which employs 120 people from the 2,100-strong Snowy 2.0 workforce. The segments are being used to line the main access tunnel and emergency, cable and ventilation tunnel at Lobs Hole.
In total, 36,000 or 27% of the 130,000-plus segments needed to line all of the Snowy 2.0 tunnels have now come off the Polo Flat production line, said Paul Broad, Snowy Hydro’s Managing Director and CEO.
“We’re proud to be manufacturing and investing locally, and providing employment opportunities for local people as well,” Mr Broad said. “The precast factory is operated by our principal contractor Future Generation Joint Venture and it is powering along.
“To efficiently and safely produce enough of these massive concrete segments to line the 5.6 kilometres of dry access tunnels is a terrific achievement.”
The factory supports the operation of the three Snowy 2.0 tunnel boring machines, which are excavating 27 kilometres of tunnels from Tantangara Reservoir to Talbingo Reservoir for the Snowy 2.0 pumped-hydro expansion of the Snowy Scheme.
The Polo Flat facility includes a concrete batching plant and segment manufacturing from two automated carousels, producing up to 24 rings, each one made of nine segments, per day.
Many of the raw materials like aggregates and sand are sourced from the local Schmidt Quarries at Mt Mary and Nimmitabel, which is reducing transport time and costs. Concrete is mixed within the batching plant, which is then transferred into the factory and poured into specially-designed moulds.
With the use of innovative robotics, the moulds progress along the carousel as the segments cure and finish. There is an onsite laboratory and testing to check the quality of every segment produced.
Snowy 2.0 is leading the way in Australia to successfully deploy and use robots to automate the process of demoulding, cleaning and application of the release agent on the moulds, before pushing them through to the next production stage. This has allowed the factory to maintain a safe and low-noise working environment for workers.
It takes approximately eight to 10 hours to cure and de-mould each segment from start to finish, then they are stored for about two weeks before being transported to site, loaded into TBMs and installed in the tunnels.
FAST FACTS – DRY TUNNEL SEGMENTS
- Number produced = 25,210
- Distance if all these segments were placed side-by-side = 86.3 kilometres
- Tonnes of concrete used = 151,260
- Equivalent rings (nine segments per ring) = 2,802
- These segments – designed to provide durability under extreme fire loads – have been laboratory tested for fire loads of 1,350 degrees Celsius for up to 120 minutes.
Snowy 2.0 project background: Snowy 2.0 is a nation-building project that will underpin thousands of megawatts of renewables and will continue to keep the lights on for generations to come.
Snowy 2.0 will link two existing Snowy Scheme reservoirs, Tantangara and Talbingo, and its new power station with six pump-turbines will be located about 800m underground. Water in the top storage will be released for energy generation at times of peak demand and pumped back at times when there is excess renewable energy in the grid, so Snowy 2.0 is ready to meet demand when needed.