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100,000 SNOWY 2.0 TUNNEL SEGMENTS LOCALLY MANUFACTURED

29/02/2024

The Snowy 2.0 Cooma precast manufacturing facility has hit another significant milestone and completed production of 100,000 of the 130,000 concrete segments needed to line 27 kilometres of tunnels for the pumped-hydro megaproject. 

More than 230,000m3 (or more than 550,000 tonnes) of concrete has been used to manufacture these seven-tonne precast segments, installed by the three tunnel boring machines (TBMs) used on the Snowy project. 

Snowy Hydro CEO Dennis Barnes said it was pleasing for the project to be manufacturing and investing locally, while also providing employment opportunities. 

“About 200 people from the 3,000-strong Snowy 2.0 workforce work at the precast factory operated by our project contractor Future Generation Joint Venture,” Dennis said. “The facility supports local employment and also on-the-job training for a number of school-based apprentices from Monaro High.”   

The precast facility includes a concrete batching plant and onsite laboratory to check the quality of every segment produced. Many of the raw materials like aggregates are sourced from local quarries at Mt Mary and Nimmitabel.

Careful consideration and design of the concrete mix, which includes waste material, has meant significant reduction in the environmental production footprint while improving the segments’ durability and performance.

Carousels utilising robotics to automate the process of demoulding, cleaning and application of the release agent on the segment moulds have been used in the manufacturing process.

One of the two carousels has now been modified to produce the precast segments for the Snowy 2.0 inclined pressure shaft (IPS). This very steep 1.65km shaft will be excavated by TBM Kirsten and will link the underground power station with the headrace tunnel coming from Tantangara.

The IPS segments involve a world-first force-activated coupling system (FACS) designed to withstand the powerful internal forces of water moving through the 10-metre diameter inclined tunnel.

Installing segments with FACS eliminates the need for a second tunnel lining, thereby improving the quality, safety and the rate of tunnel completion. 

The Snowy 2.0 precast factory will produce approximately 9,000 IPS segments, with nine used in each tunnel-lining ring. The first ring prototype has been completed, with mass production expected to start next month.

FAST FACTS

Number produced = 100,000

Concrete used = About 550,000 tonnes or 230,000 cubic metres

Segment weight = 7 tonnes

Installation method = tunnel boring machine

Equivalent rings (nine segments per ring) = 11,111

Tunnel lining length = 22.2 kilometres

News

BREAKTHROUGH MILESTONE FOR SNOWY 2.0

05/01/2024

Snowy Hydro is pleased to announce another major achievement for the Snowy 2.0 pumped-hydro project, with the breakthrough of the final three metres of the power station’s 223-metre long transformer hall cavern crown.

The Snowy 2.0 delivery team began excavating the transformer hall and machine hall caverns in June 2023. The Snowy 2.0 power station will be located approximately 800m underground at Lobs Hole in the Snowy Mountains. When completed, the machine hall will be 251 metres long and 52 metres high and the transformer hall 223 metres long and 46 metres high. Together they will form one of the largest and deepest caverns in the world, big enough to fit the Sydney Opera House inside. 

Precise drill and blast methods are used to profile the curved cavern crowns (or ceilings) and break up the rock, which is mucked out and followed by surface scaling to remove any remaining loose rock. The exposed solid rock face is then supported with rock bolts and shotcrete. The excavation sequence of the cavern crowns is carefully planned and executed, as the rock mass relaxes and moves inwards as the excavated void increases. These movements are expected and are closely monitored during the process.

So far, about 17,000 cubic metres of material has been excavated from the central heading of the transformer hall cavern crown. The heading has been advanced in 3-4 metre rounds from either end of the cavern for a total of 77 blasts.

The machine hall cavern crown breakthrough will take place in coming weeks, and widening of both cavern crowns, known as side slashing, is ongoing and planned for completion in coming months. Excavation of both power station caverns is set to continue through 2024. 

The breakthrough of the transformer hall cavern crown represents another important milestone for the Snowy 2.0 pumped-hydro project that will significantly expand the existing Snowy Scheme and will provide an added 2,200 megawatts of on-demand power and 160 hours of large-scale renewable energy storage for the National Electricity Market.

Snowy Hydro CEO Dennis Barnes said: “The breakthrough of the transformer hall cavern crown is a really pleasing milestone for the Snowy 2.0 team, reinforcing that we’re making good progress with our underground drill and blast excavation activities. We are well on our way to delivering the largest single project that will help ensure Australia’s secure and reliable transition to renewable energy.”