By Tony Carnie
The Sapref fuel refinery may have to spend months sucking up a large pool of petrol which has leaked into soil and ground water underneath Tara Road on the Bluff.
The petrol leaked out of a buried pipeline for an unknown period before it was shut down 12 days ago after Wentworth residents began complaining about the smell.
Richard Parkes, the refinery's managing director, said the petrol appeared to be trapped just above the water table, but it was possibile that some vegetation and trees with deep roots could start dying.
The company, which refines fuel for Shell and BP, planned to sink about 160 wells in the vicinity of Angelier Road and the Happy Valley nature reserve so that the spilled petrol and underground water could be sucked up for separation.
Parkes said the hole in the 28-year-old pipeline was about 4mm wide, but the company was still busy trying to estimate how much petrol had leaked.
"We have almost finalised our best estimates so that we can inform the authorities and local communities, but determining the exact quantity of petrol is difficult, as we don't know whether it was leaking over a period of days or weeks."
He said a device known as an "intelligent pig" was being driven through the pipeline at the moment to find out whether there was any other damage to the pipe, which runs from Merebank to the harbour.
He confirmed that the pipeline was "pigged" just three years ago, but said the machine had not detected any problems at the time.
"We don't have the results of the latest tests yet, but we believe that the damage is localised and was probably caused by corrosion.
"We don't know if the corrosion began on the interior or exterior of the pipe, and we will be only be able to confirm this through metallurgical and other tests."
Parkes said the damaged pipeline was shut down immediately after the leak was discovered
Meanwhile, Sapref is also due to begin repair work on a large storage tank in the harbour which sprang a leak on March 22.
The rusted tank is used for storing poisonous tetra ethyl lead, a heavy liquid used to boost the octane rating of petrol.