Regional Victorian water authority, Coliban Water, has used a state-of-the-art laser-guided tunnel bore to install a new 507m section of sewer trunk main in White Hills, in suburban Bendigo.
The opportunity to use the tunnel bore was recommended by local contractor, R&R McClure, in its tender submission. According to Coliban Water’s Manager of Infrastructure, Corey Bourne, they suggested using the laser-guided bore to ensure accuracy when installing the section of sewer trunk main on flatter areas of land.
“The laser-boring technique is similar to what is used in the Melbourne Metro Tunnel Project – only on a much smaller scale,” Mr Bourne said. “While creating the micro-tunnel required for this project, the technology has proven successful and allowed us to constantly monitor and manoeuvre the machine for accuracy.
“One of the major benefits was the added control it gave our crews where there was little tolerance for vertical deviation. “It also allowed us to avoid open trenching for this project, limiting disruption to local residents, roads, vegetation and natural habitat.
R&R McClure worked closely with subcontractor, S&Z Australia, and German company, Bohrtec, which developed the technology. A Bohrtec expert visited Australia in February 2023 to train onsite crews about operating the bore. It was the first time the machine had been used in regional Victoria, after it was used once before on a Melbourne project.
Mr Bourne said the project team was able to keep abreast of the latest innovations, equipment and construction methodologies thanks to the use of new technology such as this. “This has provided a great development and learning opportunity for Coliban Water staff and our contractors,” Mr Bourne said.
Having committed to improving environmental outcomes in its Environment and Sustainability Policy, Coliban Water continues to focus on its environmental management systems by adopting best available science and technical innovations. “The added control and accuracy the bore made it a good choice for this project over other trenchless technologies,” Mr Bourne said.
Working to overcome challenges
While trenchless technology and the laser-guided bore have come with benefits, using the machine has not been without its challenges.
“This machine needed to sit in a pit, whereas other trenchless technology such as horizontal directional drills can sit on the surface,” Mr Bourne said. “This means a larger pit was required on-site to house the machine while it drilled the micro-tunnel. In the future, there may not always be space available to do this.” The machine’s German origins could add a further challenge for Australian crews.
“Any additional parts or attachments need to come from Germany,” Mr Bourne said. “So, if there is a change on site, such as ground conditions, there could be delays.”
Catering for Bendigo’s growing population
The new sewer trunk main in White Hills replaces part of the aging East Bendigo sewer trunk main. It will improve the network’s capacity to carry sewage from the growing suburbs of Strathfieldsaye, Junortoun, parts of Strathdale and East Bendigo.
The new trunk main will accommodate greater flows and enable wastewater to be better distributed between two smaller mains that carry waste to the Bendigo Water Reclamation Plant in neighbouring Epsom.
Final work is currently being completed with the last connections being put in place. The project is one of a number Coliban Water is undertaking to cater for population growth in the Bendigo region.
The five-kilometre Epsom-Huntly Pipeline, due for completion in Autumn 2023, will increase water network capacity for Epsom and Huntly, north of Bendigo. Phase One of works at the Bendigo Water Reclamation Plant are due to commence in 2024, while surveying work has commenced on a new pipeline to connect Golden Square with the growing suburbs of Maiden Gully and Marong.
Visit connect.coliban.com.au for more information on Coliban Water’s projects.