Hydro Tasmania has marked a major milestone on upgrades to the Tarraleah hydropower scheme, with the intake tower excavation now complete.
Almost 250,000m3 of rock and soil were removed to create the deep excavation where the new concrete tower will be constructed. Tasmanian company Hazell Bros Group delivered the works over the past 27 months.
A plastic concrete cut-off trench was designed by power and water consultancy Entura protects the deep excavation from seepage from Lake King William. It also provides flexibility for construction and timing of future works associated with the intake excavation.
Hydro Tasmania’s interim executive general manager, construction, Tammy Chu, said it was an exciting time for the upgrade works project.
“This has been an impressive effort, removing 240,000m3 of rock and soil and using 3,700 rock bolts (some up to 6m long). We overcame challenges with complex geology and typical Tassie winter weather, plus local jobs were created, with a peak workforce of 30 people on the ground delivering this work,” said Chu.
The intake tower construction is the next planned phase of work. A tender was released recently.
Designed by Entura, the intake project includes a 30m-high concrete structure housing intake screens, a large steel gate and associated hydraulic hoist.
Work on the 950m connecting tunnel is also well advanced. It will connect the new intake to a future new conveyance to feed water into Tarraleah Power Station. Hazell Bros Group is working alongside Tunnelling Solutions to complete around 260 blasts, removing 100,000 tonnes of material along the tunnel length.
The Tarraleah hydropower plant in Australia’s southern-most state was built in the 1930s.
“Hydro Tasmania is proposing a major redevelopment, so Tarraleah will be ready to help meet the growing demand for energy and power the state for generations to come,” said Chu.
The Federal Government has committed up to A$65m (€37.6m) in funding for the upgrade works.
