Collaboration is a cornerstone of successfully executed trenchless technical applications.
There are often many moving parts across multiple groups working on a project, all of whom must coordinate equipment, materials and, at times, systems within a safe and ordered environment while remaining constantly conscious of mitigating environmental impact throughout the works.
Many trenchless renewals are highly complex and carry material risk. Infrastructure specialist Mullane Trenchless Pipeline Solutions excels under these conditions.
Last May, the NSW based contractor successfully completed the rehabilitation of four DN1500 pipelines within an environmentally sensitive tidal zone, delivering an intricate trenchless renewal project under live wet conditions—and, what’s more, with zero downtime between lining operations.
The project brief was demanding: a quadcell of large-diameter pipes in a pristine environment, with an active creek, an adjoining river and the presence of an endangered species among the constraints to be managed.
Working with large-diameter assets in a dynamic river ecosystem – subject to tidal fluctuation, submerged access conditions and strict environmental protections –creates significant operational constraints.
A series of approvals were required, covering everything from the management of discharged water pumped each day, through to fauna management.
In one of the more unusual project requirements, a protected microbat species was identified across several of the pipelines scheduled for rehabilitation, requiring careful location and relocation by the relevant authorities prior to access being granted.
Months of meticulous planning, as Mullane soon demonstrated, unlocked a tightly programmatic work schedule.
Two weeks of detailed site preparation, in essence, enabled one week of streamlined execution.
The UV lining process, for one, must be completed without moisture. With the DN1500 pipelines typically submerged, a range of civil and temporary works were required before relining could commence.
To create controlled and isolated work zones around the pipe structures, sheet piling was installed on both downstream and upstream sections of the creek/river.
“The key was establishing effective isolation so we could control tidal ingress and upstream flows, and then maintain safe access to the assets,” recalled Luke Woodward, Mullane Trenchless Operations Director.
“That approach allowed our crews to manage river flows, changing water levels and site constraints without compromising safety or environmental controls.”
A 35-tonne sheet piling rig and 23-tonne excavators navigated the constraints of the site to support the works, including the handling of liner boxes weighing approximately three tonnes each.
These liner boxes had to be moved into position each morning, ready for lining which meant that after each liner was installed they had a few hours of civil enabling works required before leaving site daily.
Combined with high-capacity dewatering systems and continuous monitoring, the temporary works methodology enabled rehabilitation operations to proceed efficiently despite the challenging hydraulic environment.
Significant plant and machinery were required to manoeuvre heavy lining equipment and liners, particularly given the confined footprint around the quadcell arrangement.
Here, Mullane’s construction capability – supported by specialist input from its parent company, H L Mullane Infrastructure – came to the fore.
Large scaffolding platforms were custom-built and lifted into the creek bed once the water had been pumped out. These platforms supported the three-tonne liner boxes and provided stable working areas for the lining crews.
As part of its quality assurance approach, Mullane installed full rain and sun protection over the scaffolding on both the upstream and downstream channels.
“A lot of the success came down to the work done before we arrived on site to line—engineering the sequence, procuring the right temporary works, and planning each movement so daily production wasn’t exposed to avoidable delays,” said Woodward.
“On a program like this, if one day overruns, it can create immediate knock-on effects to logistics and client timeframes.”
Continuing its commitment to achieving the best outcome for every component of the project, Mullane leased a refrigerated storage facility near the job site to ensure the liners were kept below 14°C.
This added another layer of protection to the product and helped maintain consistent curing parameters for the SAERTEX UV-cured liner supplied through Pipe Core.
“In warmer conditions, resin temperature can rise quickly,” said Chris Hill, Mullane Trenchless Director.
“By keeping the liners cool and stable, we reduce variability and protect the curing process from ambient temperature swings.”
A crane truck transported the liner boxes from the refrigerated facility to site daily. Mullane Trenchless also had large jetting and CCTV inspection equipment on standby to support preparation, verification and quality control throughout the works.
For the UV cure, Mullane Trenchless collaborated with Australian Pipeline Management (APM), leveraging the large Rausch Rehab system to deliver a fast, controlled curing process suited to the scale and pace of the program.
Through detailed pre-construction planning, specialist water management methodologies and experienced delivery teams, Mullane Trenchless completed the relining of all four pipelines consecutively, achieving one pipe installation per day, with no gap days between operations.
“One of the standout outcomes for us was maintaining continuity. Four DN1500 installations in four consecutive days,” said Woodward.
“Each shift still required additional preparation after the cure to reset the site and reposition equipment for the next pipeline. The planning effort was significant, but it allowed us to work efficiently and maintain momentum.”
Woodward believes the preparation phase gave Mullane a distinct advantage in delivering work that others may not have considered pursuing, at least not with the same continuity.
“On many projects, teams will build in gap days between installations to recover time and reconfigure,” he added.
“We’re proud that our team delivered a consistent daily cycle and maintained quality throughout. The feedback from the client and stakeholders has been very positive.”
With its head office in Somersby, roughly an hour between Sydney and Newcastle, Mullane Trenchless is something of a New South Wales specialist, while it also travels nationwide for dedicated projects.
The business thrives on large, technical and complex trenchless projects across gravity sewer and stormwater networks. Its civil construction capability also positions it strongly to deliver pressure pipe relining, an area of increased focus, particularly through the use of ASOE pressure lining systems.
More than 30 projects around Australia have utilised ASOE materials, which Mullane continues to back for their suitability in handling high pressures and large diameters.
Woodward, who has a strong civil background, notes the system’s capability across a broad range of sizes, from DN50 through to DN1400.
Now in its fifth year of operation, Mullane Trenchless is relatively young, but that has not slowed its progression in building a team with the right expertise and management depth.
The ongoing support of parent company HL Mullane, a leading water infrastructure, plumbing and electrical contractor specialist led by Director Tony Rhodes, has helped provide the platform for Mullane Trenchless to scale rapidly.
“They have a forward-thinking approach and commitment to innovation,” said Hill.
“Quite often we find that the more traditional based services offered by HLM complement the civil/trenchless projects that we specialise in and as a group we are able to offer our clients the best solution for any pipeline replacement, rehabilitation or renewal.”
The company is proud of how it has elevated its capability to deliver complex projects such as the recent tidal-zone renewal.
“We’re continuing to invest in people, systems and delivery capability so we can take on the projects others find too constrained or too high-risk,” Woodward said.
“In practical terms, trenchless made this outcome achievable without the scale of disruption that open-cut alternatives would have introduced in a sensitive tidal environment.”
No-dig solutions remain, in some quarters, a well-known best kept secret.
“Trenchless requires a different mindset for some asset owners — particularly those who haven’t seen what’s possible at scale,” Hill told Trenchless Australasia.
“A big part of adoption is education, supported by proven delivery and a willingness to consider innovative methods when the constraints demand it.”
Mullane’s growth has been driven not only by its internal capability, but also by industry relationships, something Woodward considers essential to delivering the best outcomes in trenchless delivery.
“Our goal is simple: deliver a quality outcome with the right solution, work with leading suppliers, and collaborate with specialist partners when it strengthens the result,” said Woodward.
“The industry performs at its best when teams work effectively together and that’s something we prioritise on every job.”
For more information, visit mullane.com.au/trenchless/
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