July marked an exciting milestone for Australia’s Snowy 2.0 project with TBM ‘Lady Eileen Hudson’ – the first machine to start tunnelling on the pumped-hydro mega project and the first to complete a tunnel – now underway on her second tunnel drive.
The 11m diameter CREG TBM, operated by contractor JV Future Generation consisting of WeBuild, Lane Construction and Clough, will excavate the 6km long tailrace tunnel from the Talbingo adit, to connect Talbingo Reservoir to the underground power station complex. Water used to generate 2,000 megawatts of power from Snowy 2.0 will flow out of this tailrace tunnel. Water also enters this tunnel when the power station is pumping.
After completing the 2.8km main access tunnel (MAT) in 2022, the TBM was disassembled and extracted and then reassemble with new components before commissioning. The conveyor stacker, grout batch plant, and chiller plant were also relocated from the MAT portal to the Talbingo adit.
Local parish priest Father Mark Croker blessed the TBM at an onsite ceremony with Snowy 2.0 workers in attendance. The machine was then switched on and began cutting the rock face. This is the fourth TBM launch for Snowy 2.0 and a major achievement for the Snowy Scheme expansion project.
TBM Construction Manager Derek Whelan manages all Snowy 2.0 tunnelling activities, as well as the TBM construction personnel. He was on-hand to run through Lady Eileen’s impressive components, including a new 378-tonne cutterhead, made up of 70 cutting discs each weighing 290kg that will excavate the varying geology along the tunnel.
More than 27,000 concrete segments manufactured at the Polo Flat, Cooma, precast facility will be used to line the tailrace tunnel with the segment erector, segment feeder, segment cranes, and sophisticated grouting system all onboard the TBM.
The TBM is also equipped with a guidance system that provides data to the machine’s pilot, to the nearest millimetre. This information is mirrored above ground and monitored by Snowy 2.0’s construction and engineering teams.