Dundrum Excavation recently completed an urgent project at an RAAF Base in Queensland. In less than a week they excavated 13,000 cubic meters (42,650 cubic feet) of gravel from a live runway.

Story contributed by SITECH Construction Systems

Taking part in a redevelopment project to grow a Royal Australian Airforce (RAAF) base while it’s fully operational is no easy feat. Not to mention when it employs 5000 uniformed and civilian personnel and has aircraft such as F-18 jets and C-17 transporters taking off and landing multiple times a day. 

That’s the challenge Dundrum Excavation signed up for recently when they entered a tender for a project to remove sub-base material from 500 meters (1,640 feet) x 45 meters (148 feet) of runway. The required tolerances were tight and specifications high—they would have to dig to a level of plus 0 millimeters or minus 10 millimeters (0.4 inch). And they would be working to a deadline.  “This was a live base and they wanted their runway back as early as possible,” says Michael O’Brien, Managing Director of Dundrum. “We had to excavate 700 millimeters (27.6 inches) of gravel, trim to detail, and have it ready so the bitumen could be replaced by concrete … all within just six days.” 

Dundrum Excavation has a significant presence in construction. Based out of Brisbane, the company employs approximately 65 people excavating on major projects, including roads, gas pipelines, fiber-optic-cable laying, and more. To ensure maximum productivity and competitiveness, Dundrum equips its fleet of heavy machinery with 3D control systems from Trimble. 

At the time of tender, Dundrum was running twenty machines with Trimble® 3D GCS900 Grade Control Systems installed, but none of these were available for the job. Confident of winning the tender, they approached their Trimble dealer, SITECH® Construction Systems, for support. 

Cameron Godwin, sales representative at SITECH Construction Systems, suggested that Dundrum install the Trimble GCSFlex Grade Control System as a fast alternative to a full Trimble 3D grade control system. GCSFlex is an entry-level 2D machine control system that is easily installed—without welding—in just a couple of hours, and is very quick to deploy. It is also easily upgraded to a full 3D system as a company’s needs change. Says O’Brien, “For the simplicity of what we were doing GCSFlex was great for the job, expecially since it was so straightforward to install.” 

SITECH Construction Systems and Dundrum have had a long partnership, so commitment to the project’s success was equal on both sides. The team from SITECH Construction Systems carried out all installation and delivered initial training to Dundrum’s operators, with Chris Samuel, Support and System Integration Technician, supporting Dundrum onsite for two days. 

Two GCSFlex systems were installed on a Komatsu PC 450s and a CAT 349 machine. A Spectra Precision Laser GL512 rotating laser was set up in the centre of the airport runway with the excavators working on either side to the height of the laser. The box (trench) was trimmed via a John Deere 772 grader working with a Trimble Universal Total Station. 

Dundrum’s operators got up-to-speed with the GSCFlex system very quickly because its interface is very similar to that of the 3D system. Says O’Brien, “It was basically the same screen—less information but the same thing.” 

Samuel supported the machine operators with grade checking, benching their machines, and transferring their positions using laser reference. “We had one operator on site who had never used any form of machine control,” says Samuel. “But he learnt the GCSFlex system really fast, and his accuracy was spot on right from the start—even better than the operators who were used to using 3D.”

Throughout the project, aircraft continued to use the runway even while the excavators were working. F-18s would take off—often two at a time—and land just 100 meters (330 feet)  further along the runway. The noise level meant operators and any other personnel on site were required to wear extra ear protection whenever aircraft were flying. Says Samuel, “We didn’t need to be asked twice to wear our ear plugs. I’ve never known a noise like it!” Meanwhile the heat from aircraft afterburners easily rivalled that of any Queensland day in summer. 

The unique challenges of the environment didn’t hinder Dundrum’s progress, however. With the GCSFlex system on board, O’Brien’s teams moved 2500 cubic meters (8,200 cubic feet) each day, thereby meeting their six-day deadline with ease and without overtime. Says O’Brien, “We had the solution to be quick. Without optimised machines and the right support, things could’ve gotten a little bit messy.”