Murphy Brothers, Inc. of East Moline, Ill., was contracted by Indiana Gas Co. to replace 460 feet of a 6-inch diameter steel gas main near Martinsville, Ind. This is part of the pipeline that runs from Terre Haute, Ind., to service customers in and around Indianapolis. The line needed to be replaced because this particular section of Lamb’s creek had washed out and exposed the line.

The pipe was assembled, welded, 100percent X-rayed and approved by the gas company’s technicians days before the scheduled bore and pipe replacement. The crew planned to make the bore under a state two-lane blacktop, through a cornfield, some woods, and under Lamb’s Creek with a Vermeer Navigator directional boring unit. With the pullback force of the Navigator, the bore and pullback was expected to be done in a day without a hitch.

With the drill rack set back in the cornfield, the unit drilled down-grade under the two-lane state road and down 20 feet below their entry point to the bottom of Lamb’s Creek and back up. This part of the job went smoothly. It was the pullback of the steel pipe that made this job require the adaptation, engineering and innovation skills from which new applications in pipelining are born.

When the pipe assembly was pulled back, the crew discovered it was 60 feet short of their target and the lead end of the pipe was 15 feet down, directly under the road. Estimating how much pipe you need to go down 20 feet from the entry point and under a creek can be hard to calculate, and it was conjectured that this significant grade lead to the underestimated pipe length.

With the pullback stopped, the crew regrouped and consulted with the gas company representatives as to the appropriate course of action. The crew had available pipe to weld onto the chain, but because of the necessity to bring out X-ray technicians to shoot and read the X-ray, they were looking at a couple hours of downtime.

Pipeliners experienced with directional drilling know that if a pipe chain is stalled during pullback, despite the bentonite and polymers used, the lubrication will dry, and the water used will leech out. Since the soil conditions on this job were sandy loam and gravel under the creek bottom, it makes lubrication essential.

According to Dave Shippy, Murphy Brothers, Inc. job superintendent, once the pullback was stalled, the difficulties grew. “We received permission from the gas company to employ over the 400 feet and to move our tie-in closer,” he says. “At this point, we tried to complete the pullback, but the going was tough. We had a sick feeling that the bore had dried and that the pipe had seized up.”

The pullback force of the Navigator was plenty to pull the pipe, Shippy explains, but the linkage wasn’t strong enough. The clevis attached from the 12-inch diameter backreamer to the pipe snapped and left the pipe in the bore. The crew then pulled the backreamer out of the bore and examined their options.

Their first option was to dig up the road with an excavator and dig down to retrieve the leading end of the pipe. This option was quickly discarded. No one wanted to cut the slate road and then have to tight sheet and shore up a pit 15 feet deep.

Their second option was to leave the pipe in the ground and start the process all over again with a new bore and a new pipe. This idea did not receive acceptance for the obvious expensive reasons.

Their third option was to pull the pipe assembly back out to its entry point and start the bore and pullback over again in a new bore. This last option was tried with the hydraulic winch of a side boom only to have the ¾-inch cable break in the process. The pipe was clearly stuck.

Indiana Vermeer dealer Jay Van Tress came to the jobsite and he and Shippy put their heads together and came up with a rescue plan. Van Tress had the Vermeer factory send an 8-inch diameter HammerHead pipe ramming tool. The plan was to ram the pipe through the pore to its end point. They set up the rammer by welding on a 6 to 8 reducer onto the 6-inch pipe to prepare it for the 8-inch collets that would lock in the tool.

The large pneumatic tool was lowered into the pit with two slings dangling from the excavator, and aligned and supported with a simple wood framing. As the tool started ramming the pipe in, the crew’s expression turned from concern and doubt to elation.

“I didn’t think the tool would do it,” admits Shippy. “Especially when we had already used a lot of power. I mean, we broke a ¾-inch winch cable on this stubborn pipe. We all had question marks on our foreheads when we were setting it up but smiles on our faces when the pipe started moving.”

The 400-foot pipe assembly was rammed the last 60 feet in less than an hour to a point beyond the road and about 8 feet deep where the crew dug down and tied it in.

According to Shippy, this was as novel a rescue approach as he had ever seen. “Like many others, we’ve rammed a steel pipe straight under roads but this was the first time we’ve rammed a crooked pipe chain. When you think about it, this tool rammed the whole 400-foot pipe chain with quite a bend radius in it another 60 feet. It was a terrific backup system.”

This combination of directional drilling and pneumatic pipe ramming was a success for the Murphy Brothers crew.

Without these types of technology readily available, the contractor may have faced costly alternatives. With this in mind, the solutions found on this jobsite should provide to be a valuable example for other contractors who may be faced with similar situations.