Excavation starts on stage two of Western Harbour Tunnel

The first roadheader is creating a temporary access tunnel under the road reserve. From there, TBMs will begin the twin mainline tunnels, continuing south under the highway towards Ridge Street, North Sydney.

Acciona will use a total of 10 roadheaders, each with a height of 5m, a width of 4.5m and weighing over 100 tonnes to start tunnel excavation on the north side of the harbour.

The roadheader will cut through 1,000 tonnes of rock a day, excavating a distance of 20-25m per week before a TBM takes over to tunnel under the harbour.

To date on stage 2, 23,000 tonnes of material have already been excavated and more than 1,482m3 of concrete poured in preparation for tunnelling.

The Western Harbour Tunnel project will create almost 7000 jobs and eventually

Western Harbour Tunnel is a 6.5km tunnel, designed to reduce traffic on the Sydney Harbour Bridge and tunnel by linking the Warringah Freeway with the soon to open Rozelle Interchange. It is the first new road crossing of the harbour in over 30 years.

The tunnel’s twin three-lane motorways are expected to reduce traffic on the Western Distributor by 35%, the harbour tunnel by 20% and the harbour bridge by 17%.

Stage one, which is under way, involves creating the 1.7km southern section of the tunnel from Rozelle to Birchgrove and is expected to be complete in 2025.

Stage two includes construction of the northern end of the tunnel, connections to the Warringah Freeway, tunnelling underneath Sydney Harbour and the complete tunnel fit-out. It is expected to take approximately five years.

Minister for roads John Graham said: “The start of tunnelling at Cammeray is a major milestone for this project, bringing motorists a step closer to benefiting from Sydney’s third harbour crossing.

“The new Western Harbour Tunnel will provide time-saving benefits not only for those connecting to the Rozelle Interchange, but for motorists across Sydney’s wider road network.”

Acciona was awarded the design and construction contract for stage two in December 2022.  The total budget is AU$4.24bn (£2.22bn).