Today, he is superintendent of boring for Quanta Services and specializes in auger boring. He is known throughout the pipeline industry for taking on, and successfully completing, some of the most challenging bores around.

During Thomas’ time in the industry, he’s seen a number of changes and the adoption of new technologies that have made his job easier and more productive. One of those innovations is making a comeback, and by all accounts it’s going to make a huge impact.

Thomas began using cradle boring machines back in the ’60s and ’70s as a means to efficiently install longer sections of pipeline casing, typically in cross-country installation projects, in a time-efficient manner. The cradle boring machine is becoming a new installation option with the increased demand for pipeline expansion and contractors looking for a more efficient way to install longer sections of pipeline casing under roads and railways.

Cradle bore comeback
Thomas still has two of the cradle boring machines he purchased back in the ’70s, but over time the machines started showing considerable wear and required more maintenance just to keep them running. Since the units haven’t been manufactured since the ’70’s, finding replacement parts has been a challenge.

So, Thomas took it upon himself to design a modernized cradle boring machine that incorporated many of the unique features of the units built 35 years ago, but with updated safety and production capabilities.

Thomas decided he needed a partner to make his dream a reality, so he reached out to Dave Gasmovic with the McLaughlin Group in Greenville, S.C. McLaughlin is a leading manufacturer of auger boring, vacuum excavation and underground locating equipment.

“I went over my design with the engineering team at McLaughlin and they built a prototype that I used on a project in Mississippi to install 70 miles (112.6 km) of 36-inch (91.4 cm) casing,” says Thomas. “The machine worked really well, but we realized it was too heavy. So the team went back to work and dropped the weight by half.”

The McLaughlin® CBM 48 is capable of installing steel casings ranging from 10 to 48 inches (25 to 122 cm) in diameter and casing sections up to 120 feet (36.6 m) can be installed in one pass. Powered by a 162 horsepower (121 kW) air-cooled, turbocharged Deutz diesel engine, the CBM 48 produces 170,000 ft-lbs (230,000 Nm) of auger torque.

The transmission offers five forward and one reverse speeds and a patented operator presence control hydraulic clutch ensures quick drive-line shutdown in an emergency. A centrally-mounted, fully-adjustable seat provides the operator with a clear view of the boring process and easy access to the control console, which offers joystick and switch functionality.

“The cradle boring method helps save pipeline contractors time, because it’s not necessary to set up the project as a construction pit, which is often necessary with pit-launched auger boring,” says Dave Gasmovic, president of McLaughlin. “Instead a trench the length of the casing is excavated and the cradle boring machine along with the casing is suspended in the trench using pipe-laying or side-boom equipment. This reduction in setup time can help pipeline contractors complete more bores per day.”

According to Thomas that reduction in setup time is paying off. He can typically complete an 80- to 90-foot (24.3 to 27.4 m) bore in only 3.5 hours depending on soil conditions. This includes cutting the approach, setting up the machine and completing the bore.

“Using a track auger boring machine on the same project would require a day just to set up the machine,” says Thomas. “However, I will use a track-based system on bores longer than 200 feet (60.9 m) and where rock is prevalent. In those cases the track system is more productive.”

34 bores in six weeks
Thomas put the newly designed McLaughlin cradle boring machine to the test on a 36-inch (91.4 cm) natural gas pipeline project near Elbertson, Ga. The project called for the installation of the pipeline under 34 roads and railways. The bores averaged 80- to 90-feet (24.3 to 27.4 m) in length with the longest measuring up to 200 feet (60.9 m) in length.

“We were called in because they were behind in their boring,” says Thomas. “We arrived on site in early September and completed the work in only six weeks. The project owner was very pleased with our work and the speed at which we completed the project.”

Once Thomas had the list of crossings in hand, his crew began working through the list of bores. The first step is to create the approach to the road or railway crossing. This requires excavating dirt to attain the required cover mandated for the project; in this case it ranged from 4 to 6 feet (1.2 to 1.8 m). Thomas used two backhoes and track excavators to excavate the approach areas and attain the required cover.

At the surface, auger flighting was inserted into each section of the dummy steel casing, which was then assembled by welding each section together forming a continuous string. A jacking lug, or “dead man,” is installed crossways over the top of the bore pit entrance to provide reaction force to a winch, which pulled the assembly forward into the bore.

Next the dummy steel casing was attached to the cradle boring machine by placing the casing string into a cradle on the front of the machine. The auger flighting was attached to the machine and three chains running over the top of the casing secure the string to the cradle boring machine. The chains were attached to hydraulic
cylinders, which provided even pressure on the casing to ensure a secure fit throughout the bore.

The casing string and cradle boring machine were then lowered into the trench or pit using two Cat 583 pipe layers, which suspended the string and machine in the trench and help maintain the direction and grade of the bore. A powerful 32.5-ton (29.48 tonne) hydraulic winch pulls the machine forward in the trench as the auger flighting removes spoil. The system offers an innovative adjustable winch pulling speed feature allowing the operator to set the winch pulling speed with the touch of a dial and adjust to a variety of infinite speeds as needed.

After sufficient pipe was installed to provide support and maintain line and grade, the casing cradle was removed and only the boring machine was supported. Spoil for the bore was removed by the auger flighting inside the casing back to the machine and deposited into the trench or pit.

Once the casing had been installed, the cradle boring machine was disconnected and the auger flighting was pulled back through the installed casing to remove any remaining spoil from the dummy pipe. Then the dummy pipe was extracted and the permanent 36-inch (91.4 cm) natural gas pipeline was installed using the cradle boring machine.

Since Thomas was working with normal soil conditions, he used a standard dirt head and was able to complete a 90-foot (27.4 m) bore in 30 minutes. In good soil conditions the cradle boring machine was able to bore at 3 feet (0.91 m) per minute.

The cradle boring machine was used on all but a few bores where solid granite rock was present. In those cases, Thomas decided to use a McLaughlin track auger boring machine.

Future looks bright
Overall the project was a great success and has led to a number of additional projects for Thomas.

“The new cradle boring machine provided us with great production capabilities and shined on this project,” says Thomas. “I feel like we’ve got the best boring equipment that can be bought right now, and that puts us a little bit ahead of our competition. As the pipeline market picks up, that is going to be a real advantage for us.”