After two years of delays and disputes over who should foot the bill, Sydney's M6 motorway is set to resume construction, with no extra cost to taxpayers. The £1.6 billion (A$3.1 billion) project has faced numerous setbacks since its inception in 2019, including a catastrophic discovery of sinkholes and geological faults that brought progress to a grinding halt.
The tunnel section of the motorway, which aims to link Sydney's southern suburbs to the main road network, was initially due for completion by 2024. However, significant geological challenges, including large sinkholes above the tunnel pathway and a high-angle reverse fault in the bedrock near the sinkholes, have hindered progress.
The consortium responsible for building the tunnels, CPB, Ghella, and UGL (CGU), had threatened to withdraw from the project over costs disputes with the New South Wales government. However, under a new agreement reached between the two parties, CGU will absorb the costs associated with addressing the subsidence issues that stalled the contract.
The NSW Roads Minister, Jenny Aitchison, has confirmed that work on the M6 will resume immediately and that taxpayers will not face additional financial burdens for its completion. With approximately 250 metres of excavation still required, engineers may employ 'jet grouting' – a method involving high-speed fluid to solidify the rock for safe drilling and tunnelling.
The agreement marks a significant breakthrough in resolving the dispute over costs, but it comes at the cost of a further delay to the project's completion. The M6 motorway is now expected to open in 2028 at the earliest – two years behind its original projected timeline.