The early works contract includes excavation of major shafts in the centre of the city as part of preparations for the tunnel and five new underground stations.
It will involve excavation of huge open shafts adjacent to Swanston Street to enable the underground construction of the two new city stations.
The shafts will be up to 35m deep – more than 11 storeys below the ground – and involve the excavation of enough soil and rock to fill 34 Olympic-sized swimming pools.
Excavation of the central business district’s CBD North Station will involve two shafts, which will be covered by massive acoustic sheds to reduce noise for neighbouring residents and offices. Construction of CBD South will involve the partial demolition of a car park underneath City Square.
Other works in the package include the relocation and protection of up to 100 utilities, including gas, power and telecommunications services, and a 120-year-old brick main sewer line.
These works will start within weeks, with work on the stations shafts to begin next year, following the conclusion of the environmental process currently under way and formal planning approval for the project.