In the early hours of 2 November, forty-seven people were evacuated following a collapse on the 3.6km long twin-tube Lane Cove Tunnel project in Sydney, Australia.
Contractor Thiess John Holland said the 10m by 8m hole was due to an unforeseen geological event that led to a rock slippage in one of the exit tunnels being excavated and does not impact the construction or integrity of the main tunnels. All workers were accounted for and 1,400m3 of concrete was poured into the cavity to try and stabilise the area.
A spokesman said once stabilisation works were complete, an investigation would be carried out to determine the cause.
