In the 1990s, microtunneling was still very much in its startup period in the United States. It wasn’t until the late 1980s that the U.S had its first major microtunneling program, and owners, designers and contractors were still getting comfortable with this emerging technology. One of the early adopters of microtunneling on the West Coast was Vadnais Trenchless Services, which began offering trenchless services in 1992. In 1995, Vadnais bought its first brand new microtunneling system from German-based manufacturer Soltau, which was a leading provider of machines to the U.S. market at that time.
While that machine served its purpose over the next decade and a half, technology for microtunneling machines continued to evolve – improved guidance and operations systems are allowing longer, more precise drives, while data logging and monitoring equipment provide for more information and analysis. With this is mind, Vadnais, in conjunction with mts Perforator, completed a rebuild of the Soltau machine to bring it into the 21st century.
“Basically we overhauled the machine and replaced everything; essentially the only thing left from the original machine is the steel body,” said Peter Turnbull, project manager for Vadnais Trenchless Services. “Essentially, it is now a new mts 2000 system OD 1500.”
The rebuild occurred in Vadnais’ shop in Vista, California, under the watchful eyes or Roger Skog, Vadnais’ equipment manager, and Andreas Thiele, mts Perforator’s lead engineer for microtunneling in the United States.
Thiele and mts Perforator are certainly no strangers to Soltau equipment; mts was founded in 2000 by former Soltau employees, including Thiele, following the sale of Soltau to Wirth. Eventually mts was purchased by Schmidt Kranz Group, a German holding company, and it merged with Perforator GmbH to become mts Perforator GmbH. mts Perforator opened a U.S. office in 2015 to extend sales and support to North American contractors.
For Vadnais, it had been using the Soltau machine regularly since acquiring it in 1999. However, seeing the need for updated equipment, and the need for more data, Vadnais opted to overhaul the MTBM.
“Engineers are asking us for more and more data and information, and the microtunneling drives are getting longer and longer, so we knew it was time to upgrade the equipment,” Turnbull said. The rebuild itself took just under three months from strip down to startup. Skog and MTBM operator Nicholas Cashdollar indicated that the rebuilt machine vastly improved control and feedback.
The newly built machine was put to work almost immediately to complete the Arden Road Pump Station Improvements and Pipeline Installation project for Amarillo Utilities. The job involved a crossing of I-27 for a sewer forcemain installation. SJ Louis was awarded the contract and subcontracted the microtunnel work to Vadnais.
This microtunneling portion of the project consisted of a single tunnel drive of 421 lf of 60-in. Permalok casing. Shafts for the microtunneling were trench shields approximately 15 ft deep built by SJ Louis.
The microtunnel was installed in dense clayey soils above the water table. Due to the nature of the clay, Vadnais used a Brandt centrifuge in addition to a Schauenburg MAB 300 separation plant. The project started on July 20, 2016, and was complete on Sept. 3, 2016, with the microtunnel drive taking about two weeks to complete.
“The machine performed very well,” Turnbull said. “The crew and the mts Perforator support did a great job. We were very happy with the outcome.”
From Amarillo, the “new” mts 2000 system OD 1500 will head to Sarasota, Florida, to complete the Lift Station 87 Phase 1 Microtunneling project for the City of Sarasota. The $7.7 million Sarasota project involves two microtunnel drives (690 and 592 lf) to install 60-in. Permalok casing. The project is unique in that is the city’s second attempt to complete the project, so it will be a high-profile job.
“The Amarillo job provided us with a good test case to get familiar with the newly configured machine and get everything working in top shape,” Turnbull said.
With the overhaul of the old Soltau machine and its subsequent completion of its project in Amarillo, Vadnais is turning its attention to two other Soltau microtunneling systems in its fleet. “By rebuilding the machines we able to bring old machines into the modern market,” Turnbull said.