Contractor PT Thiess Accelerates Runway Resurfacing Project for Indonesia Airport with Trimble Universal Total Station and Grade Control
Soroako is a small mining town in the center of Sulawesi island in Indonesia. The area is known for its beautiful natural terrain and land infused with nickel and copper deposits. The region has the largest open-pit mine in Indonesia, which is owned by the Canadian based mining company Vale Inco. The airport in Soroako, Indonesia is incredibly important to the people of the area. Not only does it serve a transportation hub for mining activities, it is also a launching point for residents to visit family and participate in sacred religious traditions across the globe.
Vale turned to veteran contractor PT Thiess Indonesia to apply a new sub grade surface and finish grade surface to the runway within a short time frame. Thiess has been delivering contract mining and construction engineering services to projects across Indonesia and beyond for over 20 years. In total, the project consisted of cement stabilization, re-grade, trim work and chip seal. Mark Surtees, manager of survey and technology for Thiess, and his team were more than up for the runway project challenge.
"This type of resurfacing work generally takes a month," said Surtees. "And with the Soroako airport, they wanted us to bring that down to a couple of weeks- that leaves little room for rework. We also have several mining infrastructure projects on the horizon where we could see Trimble's site positioning technology saving us time and money, so we determined this was the right time to bring Trimble on board."
Working through their SITECH® dealer, the Thiess team adopted the Trimble SPS930 Universal Total Station and the grade control system for site measurement, stakeout, and earthworks capabilities. The grade control systemy was installed on a motor grader with an auto option. The motor grader on site was guided by the Trimble SPS930 Robotic Total Station. The SPS930 was also selected to be used for survey, layout and topography survey.
Trimble total station is powered by SCS900 software. This field software delivers simple, easy to understand workflows for meeting stakeout, measurement, grade control, and quality control requirements. Thiess also adopted Business Center-HCE to create accurate digital models of the terrain up front. With this design office software and Trimble Terramodel™, the team was able to perform data prep, manage data, visualize it as needed, and share information from the field to the office.
Working side-by-side with Surtess, SITECH engineers provided training and installation help for the Trimble SPS930 total station. Once the team worked through the slope sensor setup and the initial calibration of the system, Surtess began noticing significant results on the project.
With the Trimble SPS930 system on the grader, the team's operator was able to consistently maintain the accuracy of the blade two within +/- 3 millimeters. This allowed the team to perform continuous and accurate grading, even with limited visibility and adverse weather conditions. Instead of spending time and requiring extra grade checkers to manually set string lines every three meters around the runway, the operator loaded design data into the CB430 Control Box and the machine automatically kept the grade to the specified design. During work, the control box then provided a graphical display of blade position and design. Using 2.4 GHz radio for two way communication, the Trimble total station system guided the machines to achieve the fine grade desired. When accuracy tolerances are extremely tight, as they are with most roadwork and runway resurfacing projects, Surtees believes the Trimble Universal Total Station and grade control system is an ideal combination.
Even after six days of heavy rain which stalled the project, the team was able to complete the Soroako runway ahead of schedule and within the tight budget constraints. In just over two weeks, the Thiess team laid cement stabilization of 250 millimeters, and preformed re-grade, trim work, and three top coats of chip seal and final line marking for the airport runway.
"With Trimble Universal Total Station, our job ran faster in all weather conditions; even after three days of rain we flipped on the total station and it ran perfectly," said Surtees. "We were able to reach repeatable accuracy of each graded layer with fewer passes of the grader- as a result we didn't waste time and materials from rework, and we saved fuel and machine run time."
In addition to reaching grade levels quickly, Surtees also found that the Trimble SPS930 Universal Total Station provided superior tracking for site measurement tasks. He quickly captured initial site measurements to verify design levels. He also performed grade checking and tracked as-built records within Business Center-HCE. Accessing field data, he created on-going internal and external facing performance surface report to show grade reached as well as to confirm the volume of material used vs. estimated. He was extremely happy to report that there was no extra material purchased for this project. As a result, costs were kept down despite delays, and the project was profitable.
In addition, Surtees is quick to point out that an intangible-but still critically important-project goal was also met: Thiess keeping its commitment to the Soroako community.
"The Soroako airport is a main thoroughfare, keeping it closed any longer was not an option; what the Trimble system did for us is show this local community that we will deliver when we say we will," said Surtess.
Looking ahead, the Thiess team is extremely excited to apply what it's learned on this runway resurfacing project to other work. Thiess has already rolled out three other Trimble Universal Total Station and grade control systems to larger road building and infrastructure projects. One includes road building for a 180 kilometers toll road on the Indonesian island of Java. The versatility of Trimble SPS930 Universal Total Station allows the systems to be moved from one job site to the next. So if it's not needed on a motor grader or dozer, it can be used for making other on-site measurements. Surtess believes the Trimble system has been validated and lived up to its promises so far, and using it on larger projects consistently will only increase ROI.
"Going forward, from a management point of view, when you're short on labor-which is an absolute consistency today-you can implement Trimble SPS930 Universal Total Station, and you'll have more confidence in quantities, in pricing, in timing, and in labor costs," said Surtees. "If we can have 5 to 10 millimeters more accuracy in our materials purchasing and utilization, that's thousands of dollars saved per road; it can take a project from breaking even to making a profit."