Ann: NAIF Approves Indicative Term Sheet for up to $516m funding, page-14

"The Bogong Hydro Power Station is an underground structure, with the excavation of the station box is top-down excavation utilising secant pile walls, rock anchors and excavation in rock 25 metres below the surface. Approximately 30,000 cubic metres of material was excavated, after which the power station foundations were filled with more than 10,000 cubic metres of concrete.  Pivotal to the success of the power station construction was the co-ordination of the mechanical equipment including turbines, generators, draft tubes, inlet valves and scroll casings. These significant individual pieces required installation as the power station was constructed from the depths of the excavation.

McConnell Dowell's engineers worked with our consultants in extensive value engineering workshops to reduce the price by A$30 million. The team realigned the tunnels and developed innovative materials-handling techniques for all tunnel rock."

https://www.mcconnelldowell.com/markets/power/97-bogong-hydro-power-project