Drilling phase complete on Southern Pipeline harbour crossing

Tauranga City Council's Steve Wiggill with Lucas Drilling staff Regan Lammas, Manuel Zuleta, Amy Farrugia and Terry Gardiner. Photo/supplied

The drilling phase of the Southern Pipeline Harbour Crossing project is complete.

At midday on Saturday, the drill successfully reached the Memorial Park side from Matapihi, after two weeks of drilling work.

The project has been under way since February, and the drilling work has been carried out using a method called horizontal directional drilling, which is the safest option for the environment.

The project required the drill to be accurately directed under the harbour bed at a depth of up to 35m, following a curved path and aiming for a target 76cm wide, from 1.6km away.

Steve Wiggill, Tauranga City Council project manager for the Southern Pipeline, said the weekend's milestone was an important part of the project.

"We've brought experts to Tauranga from around the world to work on this project and ensure it is successful, but it is still no easy feat to complete drilling work in an environment like this.

"Throughout this project, our focus has been on protecting our harbour and the environment. Successful completion of the drill work means the most technically challenging part of the project is now complete."

The next phase of the project involved enlarging the hole to 1.4m in diameter. Once this was completed, the 92cm diameter steel casing pipe, which has been welded together in 450m-long strings at Memorial Park, will be pulled through the hole to Matapihi.

The 80cm diameter polyethylene pipe, which is the pipe that will eventually carry the wastewater, will then be fed through the steel casing pipe from Memorial Park to Matapihi.

The final part of the project is to connect the two ends of the Harbour Crossing to the sections of Southern Pipeline at Memorial Park and Matapihi that are already in place.