Piper launches into her third and final leg

Tunnel-boring machine Piper is now firmly in the ground and moving at a pace of around 26 metres a day to complete the final 1.5-kilometre leg of our 5km Warkworth to Snells Beach wastewater pipeline. The pipeline will connect the new Lucy Moore Pump Station to the Snells Beach Wastewater Treatment Plant which is under construction.

Project manager Dirk Du Plessis says it’s one of five key projects in our $300+ million Warkworth wastewater scheme to improve wastewater services and support growth. “The ocean outfall, which will carry highly treated wastewater out into the Hauraki Gulf is already completed, and the Warkworth north-west growth servicing pipeline is in the planning stage. Together, these projects will reduce wet weather overflows and treated wastewater discharges into the Mahurangi River, creating a cleaner environment for everyone to enjoy.”

Du Plessis says the transfer pipeline project has been running smoothly since tunnelling began in September last year.

“By the time Piper finishes the final leg of the pipeline in October, she would have put into place 423 steel pipes, each weighing around 7.5 tonnes.

“To get Piper ready for the final stage, a dedicated McConnell Dowell crew spent two months getting her ready for the last and shortest leg of her journey. During this time, the crew gave her a good pampering; washing and checking her hydraulics, motors, and navigation systems as well as replacing worn out seals and mechanical parts or broken equipment damaged from her last leg.

“She roughly needs a two-month break to enable the crew to setup the equipment at the new location and to do final checks and balances before tunnelling can start.

“Once she’s in the ground, trenching between five to 50 metres underground, it would be almost impossible to get her safely out without causing damage and delays to the project.

Photo: Piper gets into position behind some of the pit stop crew

"Using her face, she can cut through and devour a smorgasbord of ground that’s transported out of the tunnel and separated from the water at a dedicated separation plant up at the launchpad.

"At the separation plant, the ground material is separated, and water is pumped back to Piper to transport much needed bentonite for lubrications and for pumping tailings back to the surface.

“A small engineering crew and drive team is stationed at the launchpad 24 hours a day, seven days a week to ensure she stays on course and to maintain the support machinery that enables her to get the job done.

“We also have another crew working simultaneously to install the high-density polyethylene pipes inside the steel pipes she installed during the first and second leg of her journey."

The Warkworth to Snells Beach pipeline is one of five major projects in the $300m+ Warkworth wastewater scheme to support growth: The Snells Beach Wastewater Treatment Plant, Lucy Moore Pump Station, the Snells Algies Ocean Outfall, and the Warkworth north-west growth servicing pipeline (which is still in the planning stage).

Photo: The Warkworth to Snells Beach Pipeline will connect the new Lucy Moore Pump Station

Meanwhile, the Lucy Moore Pump Station is getting its finishing touches. “The Lucy Moore Pump Station is practically complete and is ready to be put to work,” du Plessis says. "At the moment, we’re just finessing the site by laying pavements, finishing off landscaping, installing security lighting and putting the final touches on the 3D cladding on the control room. The new pump station and the transfer pipeline will come into service once the new treatment plant is up and running.”

Snells Beach Wastewater Treatment Plant update

Project manager Casper Kruger says more than 120 people are currently working diligently to ensure the Snells Beach Wastewater Treatment Plant is ready by mid to late 2025.

“The team is currently ramping up the mechanical and electrical installation, preparing areas for the first stage of commissioning later in 2024.

Kruger says several key structures at the plant are nearing completion.

“We have recently received the control building which houses the essential equipment and systems necessary for monitoring various stages of wastewater treatment.

“These modular units were constructed off-site to accelerate the process and address the site’s limited space.

“Their arrival marks a significant milestone in our construction timeline. People in the area may also notice an increase in concrete deliveries over the next few months as road works in and around the site get underway.

The Warkworth north-west growth servicing pipeline

The North-West Growth Servicing Pipeline – to run from the Warkworth Showgrounds to the new Lucy Moore Pump Station – is needed to support population growth and reduce overflows into the Mahurangi River during wet weather.

Further assessments are being carried out on the different route options. We plan to confirm the intended route for this pipeline before Christmas.