CONTRACTOR PROFILE Underground Rock Star
Kentucky utilities contractor among the first to put new trenchless rock drill to the test
By Randy Happel Mar 01, 2013
Located in Bourbon County, Ky., at the center of the famed Inner Bluegrass Region is the small community of Paris (population 9,200). The town is named for Paris, France, and the county for the French Bourbon family, both of which provided assistance to the fledgling Americans during the Revolution. This is the heart of thoroughbred country, where narrow, winding country roads bounded by stone and wood plank fences are fixtures, as much as the lush bluegrass pastures that dot the picturesque landscape.
Many of the world’s most famous horse farms and stables are located nearby, nestled within the gently rolling green hills, elegant old trees and miles of meticulously whitewashed fences. Among the most notable: Calumet Farm, birthplace of the 1948 Triple Crown winner, Citation; and Claiborne Farm, home of stallion Bold Ruler who sired the immortal Secretariat — the gifted stallion who in 1973 became the first U.S. Triple Crown champion in a quarter century, running away with race records in all three events that still stand today.
But don’t let the serene, lush countryside and fertile Kentucky topsoil fool you. Situated not far below is rock — solid, hard rock — and lots of it. Recently, the short 17-mile scenic stretch of Kentucky Highway 68 from Paris to Lexington — self-proclaimed horse capital of the world — was transformed from one of those lazy, winding two-lane roads into a four-lane highway in an effort to better accommodate the increasing traffic resulting from a growing population of rural lifestylers who, like their famed equine counterparts, longed for a more tranquil residence.
The contractors selected to complete the highway expansion project were more than sensitive to the historic significance and preserving the natural beauty of the surroundings. Upon completion, many received local, regional and national acclaim for how the job was handled. Among them was Kenney Inc., an underground services contractor headquartered in nearby Mount Sterling, Ky., selected to install more than 23,000 ft of new utilities; an endeavor that would include several trenchless underground bores beneath scenic Kentucky Highway 68.
Ready to RockFounder and president Lewis Kenney started Kenney Inc. in 1980 by focusing on installing underground water lines and sanitary sewers, including pumping stations and wastewater treatment facilities. The company specializes in custom excavation work and rock trenching and often serves as a sub for like contractors and municipalities. Having operated primarily as an open-cut method contractor for many years, the company expanded service offerings about a decade ago to include horizontal directional drilling (HDD) as a means to provide more diverse installation options for their ever-growing loyal customer base.
“The Highway 68 project was basically situated in our backyard, so we had intimate knowledge of the terrain and soil conditions,” says vice president Cameron Kenney. “The job involved moving an existing water line that ran pretty much parallel to the highway further out and away from the road, so additional lanes could be added. Our role was to install a new service line for the existing water main. At many of the depths required to meet cover specifications, we knew we would be facing a lot of rock.”
Within the 4.4-mile installation route, Kenney’s trenchless installation crews would encounter a 380-ft river crossing. Concerned that the lone drill in the company’s fleet of equipment lacked the capability to bore through the tough and tricky limestone and clay conditions, the junior Kenney considered subbing out the river crossing portion to another contractor. Coincidentally, he received a visit from his Vermeer sales representative.
“I was doing some homework and shopping around when I learned that Vermeer had developed a new drill designed for cutting through rock,” Kenney says. “I spoke with my Vermeer sales rep about the new technology and he told me they had developed a prototype and wondered if we would be interested in helping Vermeer with testing and so forth.”
New Kid on the BlockThe prototype referenced by Kenney is now the new Vermeer D36x50DR Series II horizontal directional drill with dual rod technology. Operated using an industry-exclusive dual threaded joint, an inner rod provides torque to the drill head, while an outer rod offers steering capability to the drill head along with additional rotational torque. A class-leading inner rod torque of 1,500 ft-lbs allows for slower turning of drill bits; hence helping to increase bit life and lower cost of operation.
Maximum fluid flow of 70 gpm and 500 psi is achieved due to fluid flowing both through and around the inner rod. This allows for the use of hole-openers to enlarge the bore using the dual rod system.
“At the time, we had a decision to make,” Kenney says. “We were either going to sub it out or purchase a machine with the capability for us to complete it on our own. The Vermeer ‘rod in rod’ drill was not yet available for purchase commercially at that time, but we had a lot of bores to complete on the Highway 68 job, so the offer to test it there worked out great for both parties.”
Go with the FlowThe project involved installing a 16-in. HDPE casing to accommodate 6- and 8-in. water main service lines, at cover depths ranging from 48 in. to 18 ft. The bulk of the line was installed open-cut — using Kenney’s fleet of Vermeer trenchers — yet there were several locations along the route that required employing a trenchless approach; most notably, the 380-ft river crossing. The D36x50DR Series II drill was used to complete all of the trenchless bores; a cumulative length of approximately 3,000 ft.
“We plan and design our own bores,” Kenney says. “Each of the underground bores we completed on the Highway 68 job was intentionally and carefully mapped out well in advance. We have intimate knowledge of the terrain and the soil conditions; we just needed a machine with the capabilities to efficiently and effectively bore through the predominantly rock conditions. Fortunately, we found that with the Vermeer rock drill.”
“In dealing with rock in general, contractors basically have three options,” Kenney says. “You’re either going to drill and shoot it (using explosives); or saw through it using rock trenchers, or you can mount a hydraulic breaker to an excavator and break it up in that fashion. But when you’re in a project like this, that included a river crossing, the only option is to do it trenchless, because blasting and trenching are obviously forbidden for environmental reasons. Blasting would likely alter the course of the river’s flow.”
Kenney’s crews used an 8-in. bit to complete the river crossing pilot bore, then came back and upsized the bore path to accommodate the 16-in. outer casing with 14-, 18- and 22-in. reamers. This number of reaming passes was necessary to successfully navigate through the tough rock. Standard bentonite drilling fluid was used to complete all bores, as very minor, if any, flow issues were experienced during drilling.
It took Kenney’s crews just shy of three months to complete the series of underground bores.
“Production rates varied depending on the depth of the different bores,” Kenney explains. “Some of the bores went as deep as 18 ft while others were only 4 ft. The deeper, longer bores obviously required more steering adjustments and corrections but on average, I would say we would average about 200 ft a day on the pilot bores. We were happy with that, especially given that most of the bores — upward of 80 percent — were drilled through solid rock.”
In addition to the Highway 68 project, Kenney also put the D36x50DR drill to another test on an installation project at the North Point Training and Correctional Facility, located in Bergen, Ky. The company used the rock drill to complete several bores — totaling more than 200 ft — to install the loop system for a new highly efficient geothermal heating and cooling system … again, all in solid rock.
“The drill worked great,” Kenney says. “Of course, we were just testing it at the time, but the performance was outstanding and our operator loved it. We only had one guy on the drill throughout the duration of the projects, and he didn’t have any complaints whatsoever. He was able to make steering corrections in the rock as needed, and ended up hitting every single exit point as designed in the plans. Accuracy is always critical. Ultimately, that’s the goal.”
Randy Happel is a features writer for Two Rivers Marketing, Des Moines, Iowa.