A mega boring machine smashing through a wall of sandstone on the edge of Sydney Harbour has marked the end of tunnelling in the city’s north.

Tunnel boring machine (TBM) Mabel has reached Blues Point, after launching in February 2019 and travelling 6.2 kilometres underground from Chatswood via new metro railway stations at Crows Nest and Victoria Cross.

This historic milestone means the twin tunnels between Chatswood and the edge of Sydney Harbour are now complete, an important step in extending Sydney Metro into the city.

TBM Mabel was the third mega borer to arrive at Blues Point.

It excavated more than 562,000 tonnes of sandstone and shale - enough to fill about 87 Olympic swimming pools.

Three of the five mega borers building the twin tunnels between Chatswood and Sydenham have now finished work. Visit https://www.sydneymetro.info. 02/20