By Lynda Myer
Following breakthrough of the final three meters of the power station’s 223-metre long transformer hall cavern crown, Snowy Hydro have announced a major milestone for the Snowy 2.0 pumped-hydro project.
In June 2023 the process of digging the transformer hall and machine hall caverns was commenced by Snowy 2.0 delivery team.
Being located almost 800m beneath the ground at Lobs Hole in the Snowy Mountains, in the Snowy 2.0 power station the machine hall will be 251 meters long and 52 meters high and the transformer hall 223 meters long and 46 meters high after completion. As one of the largest and deepest caverns in the world, together they will be enough to fit the Sydney Opera House inside.
In order to profiling the curved cavern crowns (or ceilings) and breaking up the rock, which is mucked out and followed by surface scaling to remove any remaining loose rock, precise drill and blast methods are used. The exposed solid rock face is then supported with rock bolts and shotcrete. The excavation sequence of the cavern crowns is carefully planned and executed, as the rock mass relaxes and moves inwards as the excavated void increases. These movements are expected and are closely monitored during the process.
The quantity of excavated material from the central heading of the transformer hall cavern crown is about 17,000 cubic meters until now, whereas the heading has been progressed in 3-4 meter rounds from either end of the cavern for a total of 77 blasts.
The scheduled date for advancing process of machine hall cavern crown is coming weeks, and widening of both cavern crowns, known as side slashing, is ongoing and planned for completion in coming months. Also the digging pocess of both power station caverns is slated to continue through 2024.
Considering that developing the existing Snowy Scheme, providing an added 2,200 megawatts of on-demand power as well as160 hours of large-scale renewable energy storage for the National Electricity Market, will be the advantages of breakthrough of the transformer hall cavern crown, it is an important milestone for the Snowy 2.0 pumped-hydro project.
According to Snowy Hydro CEO Dennis Barnes: “The breakthrough of the transformer hall cavern crown is a really pleasing milestone for the Snowy 2.0 team, reinforcing that we’re making good progress with our underground drill and blast excavation activities. We are well on our way to delivering the largest single project that will help ensure Australia’s secure and reliable transition to renewable energy.”
