Government blames earlier planning works for Darlington motorway collapse, which Opposition disputes

The cause of the Darlington motorway collapse stems from problems not spotted in 2016, the State Government says, starting a political slanging match.

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The wall collapse on the Darlington motorway has been blamed on issues that should have been detected during the planning process, but South Australians are no closer to knowing when they can drive on the upgraded road.

Infrastructure Minister Stephan Knoll said his early advice was that three problems had caused the collapse of the retaining wall, including imperfections in the soil, a trench caused by the removal of an SA Water mains pipe and a leaking water source.

The collapsed wall at the Darlington motorway upgrade. Picture: AAP / David Mariuz

He said the problems should have been fixed during the planning phase in 2016, when Labor was in power.

Mr Knoll is yet to receive an interim report from independent contractor Aurecon about the faults, but said he was upholding his promise to provide regular updates.

“It is now very clear that there are deficiencies in the way this project was put together,” he said.

“These issues should have been identified and rectification should have happened as part of the design and the normal course of this project being delivered.”

He said Labor infrastructure spokesman Tom Koutsantonis had serious questions to answer on behalf of the former Labor government about the project’s design.

Infrastructure Minister Stephan Knoll. Picture: Matt Loxton

Labor infrastructure spokesman Tom Koutsantonis. Picture: Tricia Watkinson

Part of the wall on a section of the $620 million project collapsed early last month.

Mr Knoll said he was still not able to provide a time frame about when Aurecon would supply its draft report, when the issues causing the wall to collapse would be fixed or when the road would be open to motorists.

“Labor’s mess will be fixed and this road will be opened so South Australians can get the road they’ve paid for and the one that’s going to help them get to and from work quicker,” he said.

Mr Knoll said the contractor had so far met costs associated with fixing the wall and he expected that to continue.

Traffic restrictions along one of Adelaide’s busiest motorways will remain in place, he said.

Mr Koutsantonis said Mr Knoll was “desperately trying to shirk responsibility”.

He said the bulk of construction had taken place during Mr Knoll’s leadership and the faults should have been picked up in monthly reports by an independent verifier.

He called on Mr Knoll to release the Aurecon report before “making accusations” about the incident.