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Rain, Flood, Contaminated Soils Can’t Stop Gator Drilling
“Because of the shallow elevation of the pipes, the drill unit was placed in a pit to launch the pilot bores,” said Eric Lyons, Gator vice president. “That made it easier to keep bends out of the pipe and hit the target. The bores terminated in a prefabricated junction box.”
A pit 20-feet wide, 30-feet long and three-feet deep was dug in the middle of a road and the drill unit lowered in and positioned for the first bore. The road is not usually heavily traveled, but it provides access to two event centers so construction had to be scheduled to mitigate impact during scheduled events.
All three bores were launched from the pit. Pilot holes were tracked and kept on grade using a DigiTrak Eclipse tracking system.
“We collected all drilling fluid returns with our 3,000 gallon LMT vac truck and a 3,000 gallon Vac King tanker and disposed of it under the direction of the EPA,” Lyons said. “Coordination with the Superfund site manager determined timing, entry locations, disposal locations and flow rates and volumes. When fluid disposal was complete, equipment was decontaminated.”
Pipe was laid out in a vacant lot and fused with a McElroy T900 machine. Each pipe string was then positioned in the road for pullback after each pilot hole was completed. Because grade was critical, holes were not backreamed prior to product installation. One reaming pass was made with an in-house reamer and pipe pulled in behind it.
The first pipe was installed over a four-day period. The second installation took longer – almost five days.
Then the weather brought an unpleasant surprise: heavy rains caused flash flooding and water in the starting pit rose to within inches of vital engine components of the Universal drill rig. Waters receded the following day, and the rig was up and running again on the final 400-foot bore. The third installation also required five days.
Start to finish, the HDD portion of the project took just over four weeks. Once pipe was in the ground, the prime contractor made connections.
In addition to 160,000 pounds of pullback, the Universal 160x240 drill rig used on the project develops maximum torque of 23,800 foot pounds of torque and has maximum spindle torque of 160 rpm. It is powered by a 350-horsepower turbo diesel engine and has double rack and pinion drive and onboard crane.
The Eclipse tracking system displays drill head location and locate points in real-time. It is well suited for on-grade installations, said Lyons.