Melbourne Metro reached the first major breakthrough at State Library station, where three massive TBMs have met 30 metres underground, connecting two excavated caverns that will become State Library station.
The roadheaders have been mining station caverns and underground passenger connections under Swanston Street, near Franklin Street, for the new State Library station.
In total, more than 500,000 tonnes of material will be excavated, with 1,500 tonnes of rock and soil removed every 24 hours.
Seven roadheaders will be used in the CBD as part of the project – four for State Library Station and three for Town Hall Station. Each weighs 118-tonnes, is 15-metres long and is lowered underground in separate pieces, before being re-assembled underground.
“This breakthrough is a huge achievement and the culmination of months and months of hard work. These giant roadheaders have been working day and night underground, building the Metro Tunnel – to run more trains, more often, across Melbourne,” Minister for Transport Infrastructure Jacinta Allan said.
The road headers have dug out more than 20 per cent of State Library Station, with excavation expected to be finished by late-2020.