![]() The ideal bore begins with a straight, tangent section inclined at the angle of entry to the ground surface. This prolongs drill string life and minimizes pullback problems. The planned path should have the fewest bends possible. The pilot bore is drilled along the planned alignment from entry to exit. It may be necessary at times to position a backhoe bucket on top of the drill head as it enters the ground to facilitate proper entry. The pilot bore should begin with the slanted head at 6 o'clock to facilitate entry without deflection upward or to one side. The pit facilitates entry of the bit at the proper angle and helps contain drilling fluids. To make entry of the drill string easier, a small entry pit usually is excavated. When the drill rig is properly set up and anchored and drilling fluids mixed, the pilot bore can be initiated. As it is unloaded on-site, the equipment and materials should be checked off against the checklist prepared for the job. Ensure that everything needed is on hand before beginning the bore. Where possible, procure a secured area near the job site for staging all equipment and materials. ![]() Simple test should be conducted to ensure the water supply is suitable. Appropriate types and quantities of drilling fluid additives should be on hand, including any special additives or components for dealing with excessive water hardness, high or low pH, or brackish conditions. Anchoring requirements should be determined. The electrical strike-sensing systems should be checked to ensure it is in good working condition. Drill pipe should be inspected for damage to the pipe and threads and replaced as necessary. This includes bits, reamers, swivels, hoses gauges, etc. Before equipment is dispatched to the job site, it should be serviced, inspected for damage and repaired as necessary. Thorough planning and a pre-bid or pre-construction walkover site inspection should avoid potential conflicts such as insufficient work areas.Įquipment and Materials A list of equipment and materials necessary for the job should be prepared in advance. If the specified exit area is insufficient, the contractor should notify the owner/engineer to resolve the problem. Likewise, the exit area must accommodate the product reel and trailer, or the pipe laid out for welding and fusing. If the equipment cannot fit into the allowable entry area, the owner/engineer should be contacted to resolve the problem. Fencing should be installed to restrict access and ensure public and worker safety. The work areas should be laid out in accordance with the specifications and traffic control plans. While the equipment is being set up, the entry and exit areas should be delineated using traffic cones and construction tape or flagging. Care must be exercised to avoid contact with underground utilities during stake-down, and to ensure sufficient reaction can be developed for thrust and pullback. Machines often are staked down, using the powered rotating augers located on either side of the spindle at the front. If the entry point is within a paved area, the pavement must be removed using a jackhammer or concrete saw, depending on the owner/engineer's requirements. A small pit usually is excavated over the entry point, using a backhoe or shovel. The entry angle usually is between eight degrees and 16 degrees, although entry angles of up to 20 degrees have been used on some large diameter projects. Depending on the rig size and entry angle, this distance may be 3 feet to 20 feet behind the entry point. Getting Started The drill rig is off-loaded and positioned over the bore centerline a sufficient distance behind the entry point to allow for the carriage height and entry angle, such that the drill bit will enter the ground at the correct location and angle.
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