As they laid those first drains, footpaths and roads, Malcolm McConnell and Jim Dowell may not have realised it at the time, but they were also laying the foundations of what would become a multi-national, multi-disciplinary contracting organisation – and a six-decade journey of innovation, growth and success.
Today, McConnell Dowell has a network of offices across more than 15 countries, employs over 3600 people, and has capabilities in building, civil, fabrication, marine, mechanical, pipelines, rail, and tunnelling and underground construction.
Over the decades the company’s tunnelling and underground expertise has developed and grown to encompass every size, technology and technique, while their geographic reach and multi-discipline capability has seen successful delivery of transport, water/wastewater, power/energy, underpass, utility and mine related tunnels and underground structures.
So, what’s behind that level of success? McConnell Dowell’s Group Technical Director for Tunnelling & Underground, Justin Shepherd, takes up the story.
A long list of tunnelling achievements
From humble beginnings blasting small diameter water main tunnels in 1973, McConnell Dowell quickly moved into auger and thrust boring solutions for rail and road pipeline crossings, followed by pioneering jacked shield mini tunnelling for long wastewater conveyance pipelines in the mid-seventies.
“This was the start of our trenchless success, a path that has seen McConnell Dowell regularly embrace new technology to lead step changes in the industry – positioning McConnell Dowell as a market leader in trenchless technology,” Shepherd says.
Over the decades, the company has developed a long list of trenchless and tunnelling achievements, including:
- Construction of the first segmentally lined shield tunnel in Singapore in 1975.
- Establishing jacked shield mini tunnel technology in Singapore and Australia in the 1970s.
- Introducing remote pipe jacked microtunnelling to South East Asia, Australia, and New Zealand in the early 1980s.
- The first contractor worldwide to utilise a slurry micro TBM to construct tunnels using the ‘Pipe Roof Method’ – commencing in Singapore in the early 1980s.
- Constructing the first NATM tunnel in Australia in the 1980s.
- Achieving unsurpassed world records in TBM advance rates for the Blue Mountains Sewage Transfer Scheme during the 1990s. This included the fastest day (172.4 m) and fastest week (703 m) of any TBM of any size or type worldwide. The best monthly average (1189 m/month for its 3-4 m dia. size class) was also achieved.
- Delivering multiple award-winning hydropower projects, desalination plants and microtunnelled outfalls during the 2000s.
- Undertaking major project components including record size-length HDD undertakings on all four of the major LNG projects in QLD and PNG during the LNG boom of last decade (QCLNG, APLNG, GLNG & PNG LNG).
- Delivering the southern hemisphere’s largest diameter TBM driven tunnel in 2017.
- Setting a new world record (surpassing the previous distance by 434 m) for Direct Pipe® technology in 2018, and then again by another 92m in 2020 (2021 m single drive).
- Seven successful sub-sea TBM retrievals.
- Completing the world’s longest large diameter single pipe jack drive of 1296 m through continuous very hard rock conditions in 2020.
In amongst all that innovation, McConnell Dowell has successfully constructed more than 150 km of tunnels over 140 projects globally, including over 110 km of trenchless / tunnelled water and wastewater projects.
“Our proudest milestone in underground construction is the highly successful Waterview Tunnel in New Zealand,” says Shepherd.
“These twin tunnels, delivered by the Well-Connected Alliance, were constructed by our teams using a 14.46 m diameter TBM and are currently the largest diameter TBM bored tunnels in the southern hemisphere.”
Direct Pipe Capability
Ultra-long distance, smaller diameter trenchless pipeline installation is a specialist field where McConnell Dowell sees a bright future, investing heavily in their Direct Pipe® capability to seize the opportunity.
“We started with the then new Direct Pipe® technology in 2014 in Thailand, successfully completing 4 km over seven drives ranging between 354 m and 790 m in length. On this same project we also completed over 3.3 km of thrust bores and over 27 km of HDD,” Shepherd says.
“Carrying out these methods together, gave us an excellent appreciation of the multitude of benefits that Direct Pipe® has over HDD and microtunnelling techniques in challenging applications such as low cover, difficult geology, sensitive environments and small site footprint undercrossings.”
When the opportunity arose to use Direct Pipe® for the Army Bay Outfall Project in New Zealand, McConnell Dowell backed itself and gained full support from their client. They successfully delivered a DN1100 ocean outfall 434 m longer than previously achieved worldwide by that method. Since then they haven’t looked back, with their highly experienced team extending their single drive Direct Pipe® world record to 2021 m on a second outfall, before completing a third New Zealand project involving a treacherous marine coastline crossing, and designing a fourth project ready for construction.
McConnell Dowell is confident Direct Pipe® is the way of the future and is actively looking to replicate their New Zealand and SE Asia success in Australia.
Kidston Pumped Storage Hydro Project
Another other exciting project for the McConnell Dowell team at the moment is the Kidston Pumped Storage Hydro project in far north Queensland.
The project is being developed by Genex Power and involves the conversion of two existing mine pits into reservoirs. The technical feasibility and collaborative design development process took approximately four years.
The construction involves significant underground infrastructure, including a large powerhouse cavern, waterway, and service shafts and tunnels to allow the transfer of water between the upper and lower reservoirs.
Once completed, the facility will generate up to 250MW of rapid response power during peak demand periods and return water back to the upper reservoir during off peak periods. The facility will generate enough electricity to power 143,000 homes for eight hours.
Creative Construction
McConnell Dowell is immensely proud of its tagline Creative Construction, believing it sets the company apart from its competition.
“Creative Construction at McConnell Dowell is the inspired engineering behind the complex infrastructure we deliver,” Shepherd explains.
“It’s the technical problems and challenges solved behind the scenes by people empowered to think creatively. It’s the alternative idea or innovation that saves time, reduces cost, or delivers more value for our customers and community.
“Regardless of whether it’s 14 metre diameter road tunnel in Auckland, the longest and largest HDD boreholes in Australia, or a challenging microtunnel in Singapore, we think creatively, apply innovation where it adds value, and maintain a safe and conservative risk approach in everything we do.”
“That’s Creative Construction,” concluded Shepherd.
As it looks towards its next 60 years of operation, the future looks bright for McConnell Dowell.