March 23, 2011Having weathered at least two major downturns in business — including the fiber bust of the early 2000s — Mike Wagner understands the need for HDD contractors to adapt. The skill comes in handy not only when operating a successful directional drilling company through 12 years of market upheaval, but also when facing down the most stubborn of barriers — in Wagner’s case, rock.
The project — completing steel casing bores through solid rock — came to Wagner’s company, Sullivan, Mo.-based Priority Communications Inc., through a former subcontractor turned gas company employee. The job lead wasn’t unusual, as Wagner attributes most of his work to word-of-mouth recommendations and referrals.
In planning his assault on the rock, Wagner assessed his fleet of equipment, which consisted of five Vermeer Navigator directional drills, the smallest a D7x11 Series II, and the largest a D24x40 Series II. Wagner also had three D20x22 Series II drills. Not interested in adding a new drill or a mud motor to his fleet, Wagner set out to find a rock-busting solution that wouldn’t require him to make a large equipment investment.
“At the time, we didn’t drill a whole lot of rock,” said Wagner. “We didn’t look for those jobs. In fact, I’d say we avoided them, letting the bigger companies take care of the rock for us.”
Wagner contacted his local Vermeer dealer to see what it had in terms of an attachment that could work with one of the drills in his fleet. The dealer’s solution was a Pioneer One air hammer well-suited to bore through rock.
The air hammer, a rental air compressor and a specialist in the operation of the air hammer, arranged by Vermeer, each made its way to the jobsite. Attaching the air hammer to the Vermeer D24x40 Series II directional drill, Wagner’s crew set out to install the 8-in. steel casing for a natural gas line 7 ft beneath a creek bed that was to remain untouched. They set the drill back 60 ft from the creek on a bank 5 ft above the creek floor, making the depth to the bore nearly 12 ft .
According to Wagner, the crew had only 300 ft to get the job done. The bore was made with a 10-in. hole opener and a 10-in. rotor-cone designed reamer through what Wagner says was nearly solid rock.
“Basically after the pit, it was all solid rock,” he said. “There may have been a couple of areas where the rock had fractures in it, but it was still hammering very hard.”
The drilling fluid used on the job was Rod-Ease, a polymer designed to keep the wear off drill rod.
On the opposite side of the creek, a hill climbed 30 ft at a steep pitch, creating a significant challenge for the crew. “At one point in time, we were 27 ft deep, and it’s not like directional drilling where you can pull back and change your angle. Once that hole’s cut in solid rock, you can’t change directions. Our operators had to be extremely careful.”
Gleaning enough experience from this job and others to share tips with contractors considering an air hammer, Wagner stresses the importance of the operator’s skill, patience and undivided attention. The feel of the machine, he says, plays the biggest role in successful operation of a drill equipped with an air hammer.
“The operator is the most critical part of a job like this. If the machine starts to bog down, the operator has to know if he’s over-steering the tool so he can pull back,” Wagner explains. “You spin your hammer up and that will relieve the pitch of the hole and open it back up where you can start steering again. It’s a very slow process. But once in the ground, you don’t have any more control. You have to do the best you can with what you’ve got.”
The air hammer, in combination with the Vermeer D24x40 Series II drill, performed exceptionally well, allowing the crew to achieve a quarter inch of production per revolution, averaging roughly 10 ft every 15 minutes. The crew went on to complete five creek crossings in total, most of which took less than three days to complete — a feat Wagner calls remarkable for a solid-rock bore.
Since completing the creek-crossing job for the local gas company, Wagner has completed thousands of feet boring through rock, gaining further experience with the air hammer and changing Wagner’s future plans of attack.
Wagner’s crews have put the air hammer to work several times since the initial natural gas line installation. A bonus, Wagner found, is that the unit performs just as well when not powering through solid rock.
“Recently we had a 300-ft bore that had periods of solid rock, then dirt, some cobble,” he said. “The softer the ground, the harder it is to steer the equipment. But the air hammer steers really well in dirt.”
While Wagner acknowledges there are other pieces of equipment capable of drilling through rock, he is convinced the benefits of working with an air hammer often outweigh any other solution available in today’s market.
Among the advantages is the lower amount of water required by an air hammer than, for example, a rotor cone. “We only run 2 gals of water per minute down the hole, which makes a tremendous impact on the amount of man hours put into a job.”
Additional cost-savings come from the fact that the air hammer does not require the use of bentonite, an additive used with water to lubricate, stabilize and clear drill cuttings from a borehole. Wagner estimates this saves his company more than $40 per tank — nearly the cost of a rental compressor.
Cost- and time-savings, while important in the current marketplace, are only the beginning of the benefits the air hammer and Vermeer drill have brought to Priority Communications, which no longer passes off rock-boring jobs to ‘the bigger companies.’
“This equipment has absolutely made us a more rounded company,” said Wagner. “We can go virtually anywhere in the United States by attaching an air hammer to one of our Vermeer directional drills. Once he drill is set up for the air hammer, all it takes is a change of the head and a rental compressor, and we’re drilling rock in a matter of an hour.”
Kelly Moore is a technical writer with Two Rivers Marketing, Des Moines, Iowa.