Gas Distribution Drilling In Steep Grades

February 2013, Vol. 68 No. 2

G & W Construction is a utility contractor based in Morehead, KY, in the foothills of the Appalachian Mountains and the Daniel Boone National Forest.

The area boasts beautiful country, but below the surface are rocky conditions. Beautiful scenery, but rugged terrain over hard rock formations makes installing water, sewer, and gas pipes in the ground tough, challenging work.

“G & W Construction is a family business started more than 50 years ago by my father,” said Darrell Alderman, owner and president. “G & W began as a general contractor building commercial structures and schools, and then evolved to sanitary sewer, water and gas construction.”

Most work today is water and gas, Alderman said. “We use open-cut construction, conventional boring and horizontal directional boring (HDD),” he continued. “The biggest percentage of our work still is open cut.”

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However, in the last 10 years, directional drilling is being used more and more often to cross under rivers, highways and railroad tracks, and in areas where terrain makes excavation difficult or impossible.

“Most projects these days have segments that call for directional drilling,” Alderman said. “For several years, we subbed that work out, but as the amount of drilling increased in 2010 we invested in a small drill unit. Then we got a larger machine with 30,000 pounds of pullback and most recently a 100,000-pound pullback model for making longer runs of larger diameter pipes.”

HDD equipment
For HDD segments, G & W uses two Ditch Witch Jet Trac models: a JT3020 AT and JT100 AT.

The JT3020 AT is a relatively compact package that develops 30,000 pounds of thrust, 4,000 foot pounds of torque, and spindle speeds to 225 rpm. The JT100 AT--the largest drill unit in the Ditch Witch line -- is powered by a 268-horsepower diesel engine. It produces 100,000 pounds of pullback, 12,000 foot pounds of torque and a maximum spindle speed of 270 rpm.

The ‘AT’ designation stands for ‘All Terrain.’ AT models have a dual-pipe drilling system designed to drill through hard rock without the use of a mud motor. It enables the 30,000-pound JT3020 AT to drill in rock other machines of comparable size cannot work through.

The mechanical dual-pipe system delivers maximum downhole horsepower and operates on low volumes of drilling fluid. The AT design has an inner rod to drive a rock bit, and the outer pipe steers the downhole tool for drilling pilot holes and provides rotary torque for the hole opener during backreaming. All Terrain models also are productive in most other types of soils.