*EDITOR’S NOTE* This article is due to be featured in the December issue of Trenchless World, be sure to check it out! Also read the technical details on this bore in this bore’s Job site story.
In the HDD trade, getting the job done right, and doing so in an efficient manner, is almost always the variable between profit and loss. Exploring new technologies to make todays difficult bores a possibility, is the key to success, for many HDD contactors. Contractors are depending on manufactures like Straightline HDD® to provide the product and experience to complete these complex requirements.
StraightLine HDD® Lead Field Engineer, Ron Becker, has more than 50,000 feet of drilling experience in the toughest conditions imaginable. “We made the commitment to get the technology to the field. The best way to demonstrate any tool’s effectiveness is on a challenging jobsite,” states Becker. And what started as a method of demonstration, nearly five years ago, has become an ace in the hole, for many contractors staring down their toughest bores. Contractors looking to successfully move forward with equipment that wouldn’t have been adequate five short years ago.
Just recently, in September- W&W Utility Construction was awarded a job with multiple bores In Pocola, Oklahoma. Drilling in this area is typically done with the standard three tooth rock bit or a roller cone bit. Due to the hard shale in this area, these methods proven to be slow, some days only gaining a few drill rods worth of progress. With over 600 feet of drilling split in the remaining two bores, W&W contacted StraightLine® to test (demonstrate) the RockEye Hammer System’s capabilities.
There were several obstacles to the completion of the job, including gas and water lines, as well as, extensive telephone drops, running both parallel and across the bores. A creek bed required one of the two bores to drop eighteen feet in depth, before resurfacing three hundred feet down range.
Was the RockEye Hammer System the strategy that W & W needed to finish the project? The final two bores took just two days to complete, at a rate of less than fifteen minutes per rod. “The production and control were better than expected. I was very impressed with the hammer,” stated Dustin Walker, of W&W Utility. “This bore went without a hitch.” Dustin stated “I can’t imagine why anybody facing rock conditions wouldn’t own one of these air hammer systems”
“Versatility is really the key to the hammer’s success,” states StraightLine ® Vice President, Joe Phillips. “The hammer is simply at home in a variety of rock and soil conditions. The RockEye Hammer Systems, that we build, are designed to turn any rig into a rock-drilling machine.” Phillips continues… “We are obviously very pleased at the successes we’ve had with the RockEye Hammer System.”
The Air Hammer system boosts the ability to double your production, with drilling rates of up to one-hundred and twenty feet per hour. The hammer’s design focuses on three features that enable the company to make this claim; power, durability and steerability. In regards to power, its simple physics: a heavier piston delivers more percussive force per blow. For example a 30lb. piston in a 5.0 model will generate nearly twice as much power as any other system on the market.
Fitting the ground engaging components with strategically placed raised carbides places the focus on durability. It is serious gage protection that acts like a shield of armor. The protection is not limited to the bit, as the carbide armor encompasses all the ground engaging components, including the bent sub and the transmitter housing. A precise steering system not only enables, but enhances the system’s maneuverability and the operator’s ability to navigate a wide variety of ground conditions. Whether facing solid hard-rock formations, soft rock, or intermittent conditions such as boulders and soil… the steering system can simply steer, precisely, through that.
In addition, and perhaps the most valuable asset of air hammer technology, is its minimal impact on the environment. When compared to other directional drilling methods, nothing comes close to the environmental friendliness of this technology. The RockEye Hammer, specifically, only requires one-half to five gallons of fluids per minute for transmitter cooling, hammer lubrication and hole-cleaning. This enables the rig to leave the jobsite essentially spotless- and just such a benefit, was a huge factor in Southern Directional Drilling, being awarded an environmentally sensitive job just outside of Ashville, AL.
The equipment onsite consisted of a Ditch Witch® 3020 Mach I rig, a 4th Generation Head and a RockEye 4.0 Hammer system. The project was the installation of a 4” gas line, near an environmentally protected stream. The bore plan called for the approximately length of 400’, with a depth of 30’, and a 60◦ turn. Lying in the path of the bore plan was a road- passing over a bridge, a utility easement and an unmarked private water line. Fluid additive restrictions were imposed, due to the risk of water contamination, therefore only air and water were used to cool the space around the transmitter. The bore would have to penetrate through 21’ of clay loam, an additional 9’ of shale rock, then across the length of the bore and back up through the exit point. The job site was first attempted, from both sides, with conventional tooling. A standard Ditch Witch 3020 rig with a conventional three tooth rock bit failed to complete the task.
Again, it was Lead Field Engineer, Ron Becker, who was brought in to complete the task.
“With the RockEye Hammer 4.0, coupled with a Sullair 900cfm x 350psi air compressor, we steered about 4% of change each rod. Our drill rate was about five minutes per 10’ of rod, “stated Becker. “We steered either left or up on every rod to the water’s edge. When it was determined we were parallel to the bridge, at the outer edge of the easement, we drilled until we started our upward pitch,” continued Becker.
As the hammer came out of the shale, it was obvious that the crew was headed under the highway, 17’ deep and no way to steer fast enough to recover. The command decision was made to pull back and remove the hammer from the bore. A StraightLine® 4th generation drill head was then implemented to follow the pilot hole, and then steer to the desired exit position.
Roy, the Operator onsite for Southern Directional stated, “This was, without a doubt, the best bore I’ve ever done. It steered faster than I have ever steered in rock, totally and completely through the bore and the hammer could have easily exited, had we steered correctly under the stream. We will purchase this piece of equipment.” The pilot was completed in two days, with the pull back only taking one day to complete.
Metro Communications just outside of Danville, IL was facing an environmentally sensitive job. The assignment was to complete an incredibly challenging bore, which threatened completion of an entire project. The task at hand was to transgress the Vermillion River near Interstate 74 and Illinois State Highway 150. The tributary serves as the water supply for the community of Danville and the construction site was just upstream from the water treatment plant. Environmental protection from turbidity and contaminants was of high concern.
Set up elevation was 20’ above water level. The plan placed the estimated 600’ bore at 15’ below the streambed before ascending to the exit point, 40’ above the surface, on a hillside across the river. The ground consisted of shale, shelf rock, and blue clay with 10’ – 12’ of river rock near the water level (1 foot minus.) The goal was to stay below the rock bed, in the blue clay under the river.
Existing fiber cable, attached to bridge structure, was present alongside the current bore path. In addition, previous bridge supports of concrete and steel remained in place at unknown depths. The bore was first attempted, without success, using a 20×22 Vermeer® rig and traditional HDD tooling. A 36×50 Vermeer followed; however, the job remained unfinished.
Again, due to a track record of success, in similar situations, Craig Bennett, of Metro Communications, called on Straightline® HDD’s Ron Becker, who brought the RockEye Hammer know how to the site.
The RockEye Hammer coupled with an air compressor, operating at a rate of 1150 cfm at 350 psi, passed through 20’of shale rock at a rate of 1’ per minute. Lack of return air flow, hampered the hammer through the coble; however the speed of progression remained much the same. Air flow, again, became the issue, as the hammer made its way down-hole through the blue clay. With pressure equalized in and around the hammer, the tool stopped working. Drilling in the blue clay was made impossible, due to air not escaping the bore hole.
A heavy bentonite mix was pumped through the hammer to bring it back through the river rock formation. A 20×22 drill was then plumbed into the bore, enabling the crew to add drill mud, along with the Straightline® Support Pac. This enabled the flow of water to run at 10 gallons per minute, from the drill, and a water/foam mix to flow from the pac. Straightline’s Ron Becker explains, “The Cetco® Versa Foam is a shale stabilizer and it thins, or lightens, the cuttings with the fine air bubbles. This allows the clay to flow back into the river rock formation until we steered up into the coble on the opposite side of the waterway.”
The crew again experienced, some drag in the river rock, as they climbed the far bank; however, they were able to operate with a smaller degree of difficulty, before steering up through another 20’ of shale, finishing through sandy loam dirt. Mr. Becker was onsite a total of two days to complete this challenging bore and even with the need for increased fluids, the jobsite was left in pristine condition and the Vermilion River… unchanged.
“In the four plus years, we’ve been in the field, with our air hammer technology, our success rates have been phenomenal,” reiterated StraightLine® Vice President, Joe Phillips. “The RockEye Hammer System is simply the most reliable, most versatile tool in our industry. The RockEye Hammer System allows the contractor to take any drill and a profitably drill in rock.