100,000 SNOWY 2.0 TUNNEL SEGMENTS LOCALLY MANUFACTURED

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.