In October 2021, Boral was awarded the contract for the Polo Flats Precast Factory to batch concrete and maintain the batching facility supplied by Future Generation Joint Venture (FGJV) in Cooma NSW, for the Snowy Hydro 2.0 Project. The contract consists of making approximately 135,000 tunnel segments of which nine segments when put together make a ring.
Each segment consists of 2.75 m³ of concrete that is poured in different shapes and interlocked to produce a structural standalone element. Each segment is 4m long x 2m wide, weighing seven tonnes and when laid end to end would reach from Cooma to Melbourne. The segments are transported to the Snowy Mountains by b-triple combination trucks and delivered to Tantangara Dam, Lobs Hole, and Marika, all sites in the Snowy Hydro Scheme, to make 27 km of electricity-producing water tunnels. The segments are installed by a tunnel boring machine (TBM) that drills, extracts raw earth and installs the segments in place as it tunnels. The 110m long TBM also grouts behind the segments as the machine tunnel bores to link the three locations.
Boral Cement was successful in securing the cement contract for the supply to sites for concrete and grout, with Boral’s heavy vehicle fleet delivering the materials for production. As of February we had produced approximately 98,000 segments or 269,000 m³.
The contract involves operating the plant 24/7 all year with a dedicated maintenance day on Sundays when there is no concrete production. We have a dedicated team of 13 split into four groups of three working week on/week off with an alternate night day shift roster. There is also a dedicated fitter for the project to do daily maintenance as required.
We have a blend of local Cooma staff and long-term employees who have worked on previous projects for Boral who drive in/drive out and this team is the nucleus of the operation. Our staff have many challenges to work with particularly a very strict concrete specification that is batched through the Dorner Batch System, which is different for those who are familiar with Command. As always, our staff have risen to meet these challenges to ensure the timely supply and compliance for each shift. The concrete production team work closely with the Boral Laboratory team for the day-to-night testing requirements and compliance.
Boral has a strong relationship with the Polo Flats FGJV team who are very supportive of Boral on site. Tim Dean, Precast Superintendent, ensures his team includes Boral as a part of the factory under the FGJV banner.
Tim says of the precast factory, “There are about 170 people and we work 24/7. We went from creating roughly 29 segments daily to an average of 190 to 210 segments a day - we’re best-in-class in the world. When Snowy 2.0 is generating its 2200 megawatts of power, these huge tunnels will carry the water down from Tantangara through the power station and empty into Talbingo reservoir. Boral is a key cog to ensure we keep the supply of the segments to the TBMs.”
This project is a ‘Good to Great’ example of the Boral team working together to deliver what is a major iconic and unique project.