“Ground disturbance issues” have been cited as the cause behind suspension of Salini Impregilo’s tunnelling work on one of the bores for the Forrestfield-Airport Link in Perth, Australia.
The two disturbances occurred within land owned by Perth Airport and Salini took the decision to halt work following discussion with the airport and the public transport authority.
A spokesperson for Perth Airport said: “Tunnelling work by tunnel boring machine Grace for the Forrestfield-Airport Link — which has not yet reached any critical infrastructure — has been temporarily suspended.
“There has been no threat to public or worker safety.”
The contractor is currently using two Herrenknecht variable density tunnel boring machines – named Grace and Sandy – to construct the 8km long tunnels for the new metro link. Grace was launched in August last year, while Sandy started tunnelling in October.
The Western Australia public transport authority said last month that Grace had completed 1.5km of tunnelling, while Sandy had completed its first kilometre.
Western Australia transport minister Rita Saffioti has said that the suspension will not cause a delay as tunnelling was ahead of schedule.
“It was always going to be a challenge through this area because of the different types of formations, so this is precautionary, they are doing the review to see what exactly happened,” she said.
“There have been two ground disturbances so as a result, TBM Grace is waiting to get clearance; also they are doing some maintenance on Grace too so they have taken this opportunity to do some further maintenance.”