A micro Tunnelling Boring Machine (MTBM) called ‘Domenica’ has been successfully lifted into a shaft at the May Rd, Mount Roskill site for Watercare’s Central Interceptor project. 

The Central Interceptor is a 14.7 kilometre wastewater tunnel that will run underground from Grey Lynn to the Mangere Wastewater Treatment Plant. The $1.2 billion project will drastically reduce wet-weather overflows in Central Auckland waterways, which occur when storm water floods the system during heavy rain. 

The 12-metre long mTBM has a total weight of almost 79.5 tonne and was carefully hoisted in sections by crane down into the 55-metre launch shaft. Once in place, the MTBM will dig link sewers B and C to connect to the main Central Interceptor tunnel.  

Auckland Mayor Phil Goff says launching the MTBM is another major milestone for the critical infrastructure project: “This is the largest wastewater project in New Zealand history, and it’s good to see that construction is on schedule despite all the obstacles caused by Covid-19,” he says. 

“When complete, the $1.2 billion Central Interceptor will significantly reduce wastewater overflows in central Auckland waterways, improving the water quality of beaches, harbours and streams and leaving a legacy of clean, safe, healthy beaches for our children and grandchildren to enjoy.”

TBMs are traditionally given female names and Domenica is named after Italian relatives of Ghella Abergeldie Joint Venture, which is delivering the project. She was manufactured in Germany and refurbished in Thailand.  

An underground operator will run the MTBM, which will travel around 18 metres per day. Link sewer C will travel from May Rd to Miranda Reserve in Avondale, while Link sewer B will start near the Mt Albert War Memorial and travel 1.5 kilometres to the Orakei sewer main. A pipe-jacking method of construction will be used.  

Watercare chief executive Jon Lamonte says the main TBM, Hiwa-i-te-Rangi, will be launched at the main Māngere construction site in June: “We’re at a very exciting stage of construction. We’ve got seven sites across Auckland operating now, with another 10 to get underway.  

“The Central Interceptor project is employing 300 to 400 people now and that figure will rise. Auckland firms, including concrete manufacturers, are benefitting from this project. It’s generating millions of dollars for the Auckland economy.”  

Once completed, the Central Interreceptor will be the longest tunnel in New Zealand. Providing both storage and conveyance, it will hold the equivalent of 80 Olympic-sized swimming pools and act as a buffer for the wastewater treatment plant in times of high flow.

For further information please click here for a video and click here to visit the website. 20/21.