As demand grows for large diameter pipelines across Australia and New Zealand, expectations around accuracy, safety and reliability are higher than ever. For bores in the 1500 to 1800mm range, the margin for error is small and the consequences of getting it wrong are significant.
Edge Underground has been preparing for this shift for many years. So far successful projects include a 1500 RCP with an 1830 millimetre bore through a clay mix, a 1350 RCP with a 1660 millimetre bore in hard rock and clay, and a series of 1500 millimetre bores in New Zealand using AdaptX technology. Across all of these, the focus remains the same: deliver the lowest risk approach for complex microtunnelling.
“At these diameters, you cannot afford guesswork,” says Stuart Harrison, founder of Edge Underground and CEO of OptionX Group. “Our entire methodology is built around reducing risk at every stage, from the first pilot cut to the final pipe in the ground.”
At the heart of this approach is the pilot stage. The pilot sets the entire job up for success. It determines line, grade and ground behaviour well before the final ream takes place. With a retractable pilot, Edge Underground’s crews have the ability to learn from the geology as they advance, make adjustments when needed and maintain tight control over alignment.
“The pilot is where we earn our confidence,” Stuart explains. “It tells us what the ground is really doing, not what we hope it is doing. Because the pilot is retractable, we have the option to adjust, refine or reassess without compromising the main drive. That is a major risk reduction tool on large diameter work.”
Once the pilot is complete, the ream stage becomes the next point where risk has to be actively managed. This is where serviceable reamer technology, developed through AdaptX, sets the system apart. Access windows are built into the reamer, allowing full recovery of all tooling at any stage of the job. If tooling needs to be replaced, rebuilt or serviced, it can be done without losing the drive.
“In traditional setups, once the head is out there, you are committed,” says Stuart. “With our serviceable reamers we can bring tooling back, rebuild it and go again. That means we control the condition of the equipment for the whole bore, not just at the start. On a 1500 or 1800 bore, that level of serviceability is critical.”
Accuracy, serviceability and reliability form the foundation of this method. In large diameter microtunnelling, accuracy protects the asset, and the ability to service tooling mid-drive protects the schedule. Reliability ensures the system performs consistently from launch to reception, even when clay, rock or transitions increase the forces on equipment.
“Large diameter work has a reputation for being high risk,” Stuart says. “What we are showing is that with the right technology and the right process, it becomes predictable and repeatable. That is what asset owners and head contractors actually want. They are not just buying a bore; they are buying certainty.”
With advanced technology, retractable tooling and a proven pilot to ream methodology, Edge Underground continues to demonstrate that large diameter microtunnelling can be carried out efficiently and with reduced risk. Whether in complex clay mixes, hard rock, or the variable geology found across Australia and New Zealand, this least risk approach provides clients with confidence that the job will be delivered accurately and dependably.
“For us it always comes back to this,” Stuart concludes. “If the project cannot fail, then we design the method so it does not. Large diameter microtunnelling is no exception.”
