By Ashley Karen
Snowy Hydro will not be permitted to continue tunnelling at Tantangara until it verifies it will cause no more environmental damage.
TBM Florence is excavating the headrace tunnel on Australia’s Snowy 2.0 project, which in December, was transitioning from a soft material into harder rock conditions when a depression developed on the surface above the TBM.
At the time, Snowy Hydro conveyed the integrity of the tunnel had not been compromised, and while work to remediate the surface depression was ongoing, tunnelling was continuing. Also, a safety exclusion zone was applied near the surface depression.
Subsequently, it expressed the tunnel boring machine was put on hold temporarily while remediation programs were finalized.
The New South Wales government has levied conditions on Snowy Hydro before tunnelling can continue.
“Snowy Hydro must prepare a modification report demonstrating how the project can safely progress without further environmental damage. It will also need to include further geotechnical studies and detail how it will stabilize and remediate the site. That modification report will be placed on public exhibition once received for community feedback”, a Department of Planning and Environment representative notified T&TI.
“Tunnel boring at the Tantangara location is on hold until the Department approves for operations to continue.”
Earlier in May, Dennis Barnes, Snowy Hydro CEO, pointed out that project completion could be postponed by up to two years because of ongoing problems. He noted the soft ground that suspended tunnelling at Tantangara; some technically complex design elements requiring more time to complete, making the final design more expensive to build; the effect of global supply chain disruption and inflation affecting the cost and availability of a skilled workforce, materials, and shipping; and the Covid-19 pandemic.
Florence is the third and final tunnel boring machine launched on the project. It had excavated approximately 150m and was at a depth of 30m when the 9m-deep depression appeared.
Meanwhile, TBM Kirsten, worked by the principal contractor Future Generation JV and has tunneled 2.9km to reach the underground power station cavern complex.
As claimed, Snowy 2.0 is Australia’s biggest renewable energy project. It will connect Tantangara Reservoir (top storage) with Talbingo Reservoir (bottom storage) via 27km of tunnels and a power station with pumping capabilities. This will allow water to be released for energy generation at peak times of demand and pumped back to the top storage when there is excess renewable energy in the system, ready to generate again.
