Auckland’s mammoth City Rail Link project is one step closer to being completed, with a massive pile of dirt excavated at the start of construction put back in place today.

Over 130,000 cubic metres of dirt was removed from a hill in Eden Terrace to enable the construction of tunnels through to Britomart in the central city.

Some 45 trucks a day moved backfill spoil from quarries in southeast Auckland back to Eden Terrace. About 200 workers toiled on the project, starting with handheld spades four years ago.

With the hill removed, 71 concrete piles were driven deep into the ground to anchor a curved retaining wall to support the railway line’s portal into its tunnels. The piles ranged from between 42 metres and 8m long.

A historic colonial cottage perched above the hill had to be removed before excavation work could begin.

“In many ways, the hill was the City Rail Link (CRL)’s ‘Everest’ – a mountain of a job completed successfully with larger-than-life high-tech machines and wonderful innovation,” CRL chief executive Dr Sean Sweeney said.

“This was building for Auckland’s future on a grand scale – all the materials we used can be measured by the tens of thousands,” Sweeney said.

Workers completed cut and cover tunnel construction last October. That allowed the dirt to go back in place.

Auckland’s mammoth City Rail Link project is one step closer to being completed, with a massive pile of dirt excavated at the start of construction put back in place today. Photo / City Rail Link

Over 130,000 cubic metres of dirt was removed from a hill in Eden Terrace to enable the construction of tunnels through to Britomart in the central city. Photo / City Rail Link

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Some 45 trucks moved backfill spoil from quarries in southeast Auckland back to Eden Terrace a day. About 200 workers toiled on the project, starting with handheld spades four years ago. Photo / City Rail Link

“The area has been transformed, reshaped and filled back in again,” Link Alliance project director Francois Dudouit said.

“I am proud of the teams involved in achieving this enormous milestone. Much of this extraordinary achievement is hidden from view as 85,000 tonnes of dirt now cover the complex and significant structures built below,” Dudouit said.

The backfill has been compacted to prepare the hill for future use by Auckland Council’s urban regeneration organisation Eke Panuku. A street above the hill would also be re-aligned to its original shape.

Raphael Franks is an Auckland-based reporter who covers breaking news. He joined the Herald as a Te Rito cadet in 2022.

This article was originally published on the NZ Herald here.