The incident took place in the first tunnel just east of the Airport Central station box. There was no explosion and no one was injured.
The pipe supplies compressed air to the TBM and the working chamber on TBM Grace. Initially TBM Grace continued to operate using a back-up air compressor.
As a precautionary measure, both TBMs have now been stopped to allow all pipe conenctors to be re-checked.
The pipe connector had recently been inspected. An investigation is under way into what caused it to fail.
The PTA is working closely with the contactor, Salini-NRW. WorkSafe is aware of the incident.
Much earlier in the day, a blockage in a pipe feeding into the slurry treatment plant at Forrestfield caused a pipe cap-end to come off. Again, there was no explosion. This has been repaired.
Media line: (08) 9326 2526 or media@pta.wa.gov.au