Work was under way for just a short time when the directional-boring crew ran into trouble. "We were boring under a creek to install pipe for a rural water system on the outskirts of Oklahoma City," said Keith Hobgood, vice president of KJ Construction Inc., Edmond, Okla. "We hit rock. It was hard, hard limestone." The KJ crew used its largest computerized "trenchless" directional boring system, a Ditch Witch JT2720, which produces 27,000 lb of pullback force. To go through the limestone, crew members installed a bit designed for boring through rock, but progress was very slow. Days passed with little headway.
"We wore out three sets of teeth," said Hobgood. "Then the housing snapped off." He considered renting a mud motor and auxiliary mud system to make the bores, but such expenses had not been factored into the cost of the project. Then Hobgood heard about a new rock bit. He made arrangements to try the bit, called the Rhino, on the creek bore. A new downhole tool was bolted onto the boring system, and work resumed.
"The bit punched through the rock, and we were able to make necessary steering corrections to complete the bore in 10 hours," said Hobgood. Four-inch diameter HDPE pipe was pulled back the following day. The total bore length was 407 ft with 290 ft through solid rock.
Hobgood praised the bit's smooth cutting action. "The old rock bit caused excessive vibration," said Hobgood. "The whole machine shook while we were trying to bore. With the new bit, there was no vibration at all. It was very smooth."
Although designed for hard boring conditions, the bit works well in dirt, making it unnecessary to change bits as soil conditions change.
Profile of a boring contractor Some contractors find success by broadening the scope of their operations. KJ Construction built a thriving business through specialization. The company focuses on underground boring, installing short runs of cable and pipe that connect homes and businesses to water, gas, telephone, and electrical utilities. KJ's work load, by volume, is telephone, gas, water, and custom boring, including electrical service work.
KJ is owned by brothers Keith and Jeff Hobgood. (Jeff is president.) They've been in the utility construction business for 16 years. For most of that time, the majority of their work has been telephone construction. But they've recently done a lot of gas work, and they're beginning to do more and more water-pipe installations.
They initially got directional boring equipment to enable better service installations. "We didn't plan to do custom boring-and we've never marketed ourselves as a custom-boring business. But we're getting more and more calls to do custom jobs," said Jeff.
Keith says KJ projects are evenly divided between new construction and repairs (replacing old cable and pipe). Directional boring has brought a new dimension to KJ's capabilities. KJ's reputation as a directional boring specialist is generating a growing demand for custom boring work. Every workday, weather permitting, the contracting company has more than 20 crews in the field using compact vibratory plows, trenchers, and horizontal directional boring equipment installing service lines.
To do more custom work KJ invested in a larger directional boring system. "We got a job installing 8-inch-diameter steel pipe and another project relocating utilities along a highway," said Keith. "We felt that we needed a more powerful machine to make longer bores." While opportunities for custom work are increasing, Jeff says KJ will continue to be a service-line specialist. "The strength of our company is built on service work, and we do not plan to abandon it."
The directional-boring trend The Hobgoods believe a growing percentage of installations will be made with horizontal directional boring equipment. "More and more project owners and general contractors are becoming aware of the benefits of directional boring," said Jeff. "And they want to use it on their projects." Whatever the method of construction, KJ is committed to maintaining the highest standards of quality.
"We do quality work at a fair price," Jeff continued. "Our people know their jobs and don't cut corners. We've been in business a long time, and we will continue to provide the best possible service to our clients."
KJ currently owns two directional systems and plans to add another compact unit in the near future. One unit is 54 inches wide and 200 inches long. It is powered by an 85-hp class diesel engine and develops 1800 ft lb of torque. Maximum spindle speed is 200 rpm. The other has a 125-hp-class turbo-charged diesel engine. It has maximum torque of 3300 ft-lb and spindle speeds to 195 rpm. The boring unit is 70 inches wide and 236 inches in length. Both models are self-propelled, self-contained units, incorporating an engine, hydraulic system, and downhole fluid delivery system in the drill frame. Built-in pipe racks carry enough drill pipe to complete most jobs.