Florence the machine to get a boring friend at Snowy 2.0
By Mike Foley
A fourth giant tunnelling machine will be added to the Snowy 2.0 pumped-hydro project to help beleaguered borer Florence, which has twice been stuck deep underneath the Australian Alps.
Snowy 2.0, which has been beset with delays and cost blowouts, is racing to meet its 2028 completion deadline. The new machine is being brought in, at a cost of about $75 million, in a bid to prevent further hold-ups.
The water intake at the Talbingo reservoir, which Florence is tunnelling towards.
Chief executive Dennis Barnes said Florence was due to hit an 800-metre-long fault zone with unstable ground in a couple of years and “you don’t want to die wondering” whether she could get through it.
“We’re getting ahead of a risk … If we wait for Florence to access this [fault zone], we’re waiting a few years before we know whether that machine could handle it,” he said.
“Our expectation is that Florence couldn’t handle it, so we need a new machine to do it.”
Snowy 2.0, designed to provide back up for intermittent renewable energy, was launched in 2017 with an expected price tag of $2 billion and an end date of 2021, but its cost has since blown out to $12 billion. The new machine will come from the existing budget.
Florence, which can bore through up to 12 metres of rock a day at top speed, spent most of last year stuck in soft ground less than 100 metres into her work under Kosciuszko National Park. Then on May 16, she became wedged in hard rock while excavating a curve in the tunnel and it took a team of contractors with high-pressure water jets seven weeks to blast her free.
The new borer will help Florence complete a 17-kilometre tunnel connecting the Talbingo reservoir to the powerhouse, allowing water from the dam to flow down and spin electricity-generating turbines.
Barnes said while the impending fault zone was not a surprise, recent testing revealed it was far more geologically challenging than earlier indicated.
“We’ve carefully considered a range of options to get through the fault zone and overcome the initial design immaturity,” he said.
“Bringing in a fourth machine is the best way to keep the Snowy 2.0 on track for its target completion date of December 2028.”
The boring machines are typically named after women – Lady Eileen Hudson and Kirsten are the two others excavating separate tunnels for the project – but Barnes said First Nations people would be consulted about the new machine’s moniker.
Snowy 2.0 will seek approval from the NSW government to revise its project plans, which will involve constructing a new underground portal. There is no proposal to increase land clearing or water impacts.
Snowy 2.0 is an expansion of the original Snowy Mountains Scheme, which opened in 1972 with 16 dams and 10 hydroelectricity projects. Once completed, it could generate enough electricity to power 3 million homes a week.
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