Central Interceptor Tunnel Boring Machine reaches 10-kilometre milestone

Hiwa-i-te Rangi Tunnel Boring Machine (TBM) has reached the 10-kilometre mark after leaving a site next to Māngere Wastewater Treatment Plant in August 2021, as she heads to Pt Erin, Herne Bay to build the 16.2-kilometre Central Interceptor wastewater tunnel.

The almost 200m long TBM is currently 100m north of the Haverstock Rd Central Interceptor site, Sandringham and sitting 70m below ground as she builds the 4.5m diameter segmented tunnel. The TBM travels around 15m per day and lays eight to ten tunnel rings. The Central Interceptor project will significantly improve water quality in streams and beaches, by capturing combined stormwater and wastewater flows and taking them to the treatment plant for processing rather than discharging into the environment during heavy rain.

Central Interceptor executive programme director Shayne Cunis says the latest milestone is particularly sweet: “It’s great news, coming almost two weeks after Hiwa-i-te-Rangi successfully broke through the latest shaft at our Haverstock Rd site, Sandringham etc.

“Our works programme is progressing safely and smoothly. We’re on track to see section one of the tunnel from May Rd, Mt Roskill south go live by the end of the year. I am immensely proud of all the construction teams producing this highly complex, technically challenging engineering project. Their work is world-class.”

The Central Interceptor project is being delivered by Ghella Abergeldie JV, with around 600 staff working across 16 sites in Auckland. Ghella Abergeldie JV project director Francesco Saibene says the 10-kilometre milestone came at a good time: “I hope our tunnellers can unwind over the Easter break. Psychologically, it’s a good feeling knowing we can enjoy some rest having reached this point. We can return to work refreshed and focussed on the next challenge: breaking through into the Lyon shaft in May.”

Meanwhile micro-Tunnel Boring Machine Domenica is also hard at work, tunnelling the final drive to build Link Sewer B, the second of two branch sewers to intersect the main tunnel. A giant new pump shaft and pump station are also nearing completion at the Māngere site. The pump station will send flows from the main Central Interceptor tunnel to the neighbouring treatment plant for processing.