Melanie Kembrey, 22 February 2016

The last chimney stack at the former Shell oil refinery in Clyde has finally fallen – five explosions and more than 30 hours later than expected.

The remaining tower – which came to be personified as the “stubborn stack” – submitted to its fate about 6.30pm on Monday.

After nearly five decades of towering over the Parramatta skyline, the defunct stack was due to fall with four others in half a minute on Sunday morning.

But when the explosives were detonated and the four other stacks crashed down in a cloud of dust, the fifth stack remained intact and upright.

While some on social media took inspiration from the solitary structure’s defiance, it has no doubt caused a headache for the site’s owners Viva Energy Australia.

The company spent six months planning the demolition of the stacks, the final major step in dismantling the former refinery so it can be converted into a fuel storage terminal.

A large exclusion zone was established, emergency services were in place, neighbours were warned and police patrolled the M4 motorway in preparation for the explosions on Sunday.

After two full-strength blasts failed to topple the tower, the demolition experts detonated two weaker blasts in a deliberate strategy to “chip away” at and weaken the structure.

On Monday evening, viva’s engineering manager Vince Neville confirmed the job had finally been completed.

“We worked in close consultation with demolition experts, Government regulators and emergency services throughout the day to ensure the plan was executed safely, with minimum disruption to our neighbours,” Mr Neville said.

“Although things didn’t go to plan yesterday, nothing went wrong and we’re pleased that the stack has been safely demolished and we can continue to focus on converting the terminal to improve its operational capability.”

Liberty Industrial, the company contracted to oversee the removal of the stacks, will also oversee the demolition of the Sydney Harbour Control Tower at Barangaroo.

“Each stack on the Clyde site was quite different and a conservative approach was taken with the fifth stack due to its unique composition and location to Terminal equipment,” the company’s founding director Clinton Dick said.

“We are pleased that the stack is now safely grounded.”

Master Builders Association of NSW executive director Brian Seidler said it was unusual for a demolition by controlled explosives to be unsuccessful as it was a highly specialised field.

Two of the most common reasons for a “stand-up” – when a structure does not collapse after attempted demolition – include that one or part of the explosive charge did not work.

“The other thought is that the steel used and the concrete used and all of the building material used were far stronger than anticipated,” Mr Seidler said.

“But I guess if the four went down reasonably without a problem it is more likely to be a fuse problem than this particular one was built stronger than the rest.”

The oil refinery and chimney stacks were switched off in 2012. The demolition of the refinery is expected to free-up more than 40 hectares of land, which Parramatta Council hopes to use to kick-start an eco-industrial precinct in the area.

Extracted in full from the Sydney Morning Herald.

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