Horizontal directional drilling (HDD) is a valuable trenchless technology, perhaps most at home in utility construction but also with growing potential in pipe repair and replacement scenarios. It is an efficient and highly accurate method of tunneling from Point A to Point B without disturbing the surface and while avoiding buried utilities.
Here are a few recent innovations in HDD drills and tools, as described by leading industry manufacturers.
Mighty mini-jet
The TERRA Mini-Jet from TERRA of Switzerland, an ISO 9001-certified manufacturer, comes in compact or long versions. Able to turn 90 degrees in 50 feet, the units can be surface-launched or launched through a 45- to 50-inch-long pit. They have 10,126 foot-pound torque, 8.8 tons thrust/pullback force, and a maximum drilling length of 164 feet. Additional rods increase drilling distances to 265 feet, especially in 2- to 3-inch diameter holes.
Depending on soil conditions, the drills can bore channels up to 10 inches in diameter. The ADBS (automatic drilling and backreaming system) instantly and automatically matches speed and torque to ground conditions. A new chain drive delivers increased power with no power losses at low speeds.
Two 6-hp Honda engines power the mixing and pumping system. Drawing water from rivers or lakes, the injector with suction hose can mix drilling mud in less than five minutes. Maximum drilling fluid is 9 gpm/797 psi. The hydraulic system, powered by a 2-cylinder, 20-hp Honda engine, delivers 10 gpm/2,537 psi. A control switches off the engine in low-oil conditions. Call 800/458-5238 or visit www.terra-trenchless.com.
Compact drill addition
The Astec EarthPro Series DD-2024 horizontal directional drill from Astec Underground offers 20,000 pounds of thrust/pullback force with capability of up to 2,400 foot-pounds of rotary torque.
Powered by an 85-hp B3.3C Cummins turbo-charged diesel engine, the drill has field-proven, quad rack-and-pinion drive with adjustable force limiter, independent rear stabilizers, front-drive track system for traction and balance, and a dual stake down system. The machine is equipped with a tethered travel control unit to help operator visibility during tramming and transport. The Es!Lok system is integrated into the controls for added safety. Call 800/527-6020 or visit www.astecunderground.com.
More power, less noise
The extended-range, self-contained JT3020 Mach 1 horizontal directional drill from Ditch Witch has 30,000 pounds of pullback and can bore pilot holes up to 4.5 inches and backream diameters up to 12 inches — all at less than 82 dBA at the operator’s ear. The 148-hp engine’s cooling design automatically increases horsepower when drilling conditions become more challenging.
The fluid mud pump delivers 42-viscosity drilling fluid at 50 gpm, increasing drill efficiency. A redesigned workstation puts all the information operators need during a bore in their line of sight as they look at the tool joint. A streamlined, easy-to-read, menu-driven LCD screen provides real-time status of the pipe makeup and breakout cycle.
The drill’s rack-and-pinion thrust drive has a welded double rack that prevents the pinion from misalignment and distributes the load equally for less wear. The redesigned anchor system sets up easily and holds firm in any soil condition. The anchor motors do not require disconnecting and provide 10,000 foot-pounds of torque. Call 800/654-6481 or visit www.ditchwitch.com.
Underground piercing tools
The Big Shot line of underground piercing tools from Footage Tools Inc. has barrels machined from solid billets of high-grade chromoly steel. A phosphate coating on the piston minimizes corrosion.
The tools have a relieved midsection barrel for increased travel through soils, a flexible air tube assembly that prevents a shift in the air hose from compromising the trajectory, a replaceable nose pin, and accessories that include cutting heads, expanders, and pipe-pulling extensions. Models are available in 2-, 2 1/2-, 3-, and 4-inch sizes with expanders accommodating two models up to 5 1/2 inches. Call 888/737-3668 or visit www.footagetools.com.
Steerable thrust boring machine
The PD-6 steerable, locatable hydraulic thrust boring machine from Pow-R Mole plugs into any 3,000-psi hydraulic source. Available with more than 84,000 pounds of thrust, the 4- and 4 1/2-foot pit-launched units set up in confined areas where directional drilling is impossible.
The machines can install up to 8-inch water or sewer lines using any type of pipe as long as 150 feet. They also can pipe burst. The dry bore system requires no water tanks or mud pumps. An OSHA-approved push/trench box certified for 12-foot depths in A-, B-, or C-type soils is available. Call 800/344-6653 or visit www.powrmole.com.
Steerable boring system
The compact Grundodrill 4X from TT Technologies Inc. offers 9,800 pounds of thrust/pullback force. The four-auger stake down system enhances stability to maximize thrust and pullback. A dual hydrostatic pump system allows optimum control during drilling operations. The drill’s computerized Smart Vice system automatically performs vice cycling operations, providing operators with single push-button control, improved efficiency, and faster drill times. The self-centering vice also reduces wear and tear.
Designed for residential or commercial use, the lightweight unit can be transported on a trailer pulled by a one-ton truck, and requires minimal crews to operate. The drill’s steel track with bonded rubber pads improves traction and minimizes potential damage to concrete and turf. Call 800/533-2078 or visit www.tttechnologies.com.
Pneumatic piercing tools
More than 17 models of HammerHead Mole piercing tools from Earth Tool Company LLC have the clamped rear anvil and tailbolt system for fast, easy field maintenance. Contractors can assemble the 2- to 8-inch tools with hand tools, and without breaker bars or special fixtures.
Internal wear rings eliminate metal-to-metal contact. Available on many 2-, 2 1/2-, and 3-inch models, the Power Port quarter-turn reverse locks the tool into forward or reverse. Replaceable head tools and Active Head piercing tools for tough soil conditions are available. Call 800/331-6653 or visit www.hammerheadmole.com.
