M6 Tunnel Rockdale: Ground collapses around tradies as giant sinkhole opens up
A contractor responsible for the controversial M6 tunnel project has denied there is any link between two sinkholes that opened above the project in just over a week.
Workers were about 40 feet below ground level Saturday morning when they exited the tunnel after noticing a “slight movement” in the roof.
Sand clay began leaking into the tunnel, which is now closed for remediation and investigation.
The subsidence has created a visible sinkhole in the surface at a location on the airport side of West Botany Street in Rockdale.
The site is about 150 meters away from another section of the tunnel, which was evacuated on March 1 when a large sinkhole appeared, causing a partial collapse of the building.
A large sinkhole opened on Saturday at a construction site (pictured) set up as part of ongoing work to build the M6 tunnel at Rockdale in Sydney’s south
On Sunday, Glyn Edwards, general manager of tunneling for CPB Contractors, said the two subsidence incidents were ‘not related’.
‘They’re not connected. They are two completely different types of geotechnology. They are two separate locations,” he said.
‘This one here is completely within the construction site.’
While acknowledging that the situation was “unusual”, the tunneling general manager said he did not consider the formation of two sinkholes to be “an extraordinary coincidence”.
The CPB has already started an investigation into the subsidence and will only resume work if SafeWork NSW and Transport for NSW give their approval.
“At this time we do not know the cause and we will not speculate on what the cause is,” Mr Edwards said.
‘What we are going to do is ensure that the location is safe and we will not move forward until we have the methodology in place.’
The CPB started pumping concrete into the sinkhole on Saturday afternoon and expects to complete the job on Sunday evening.
“Safety is actually our top priority,” Mr Edwards said.
Deputy Secretary of Infrastructure and Place for Transport for NSW, Camilla Drover, said there had been no impacts to the public or utilities as a result of the sinkhole.
The latest incident comes after a huge sinkhole (pictured) opened just over a week ago under an industrial complex just 150 meters away.
She said the department would now take stock and assess options, but she did not expect any delays in the delivery of the M6 Tunnel Stage One.
“Our focus now is on investigating and understanding what has happened, but more importantly how we will move forward and complete the tunnel work,” Ms Drover said.
The commitments come nine days after the first sinkhole opened on West Botany St in Rockdale and part of the Kirby Industrial Park closed.
Shocking images of the gaping hole show it has swallowed up part of the footpath and the ground beneath a building.
You can see the building subsiding in the middle after the ground beneath it disappeared into the sinkhole.
Detailed geotechnical and engineering assessments will be carried out at both sinkhole sites to determine if it is safe to continue work.