Pilot Hole

Pilot Hole Reaming

Drilling Mud

Pullback

General Guidelines

• Select the crossing route to keep it to the shortest reasonable distance.
• Find routes and sites where the pipeline can be constructed in one continuous length; or at least in long multiple segments fused together during insertion.
• Although compound curves have been done, try to use as straight a drill path as possible.
• Avoid entry and exit elevation differences in excess of 50 feet; both points should be as close as possible to the same elevation.
• Locate all buried structures and utilities within 10 feet of the drill-path for miniHDD applications and within 25 feet of the drill-path for maxi-HDD applications. Crossing lines are typically exposed for exact location.
• Observe and avoid above-ground structures, such as power lines, which might limit the height available for construction equipment.
• The HDD process takes very little working space versus other methods. However, actual site space varies somewhat depending upon the crossing distance, pipe diameter, and soil type.
• Long crossings with large diameter pipe need bigger, more powerful equipment and drill rig.
• As pipe diameter increases, large volumes of drilling fluids must be pumped, requiring more/larger pumps and mud-cleaning and storage equipment.
• Space requirements for maxi-HDD rigs can range from a 100 feet wide by 150 feet long entry plot for a 1000 ft crossing up to 200 feet wide by 300 feet long area for a crossing of 3000 or more feet.
• On the pipe side of the crossing, sufficient temporary space should be rented to allow fusing and joining the PE carrier pipe in a continuous string beginning about 75 feet beyond the exit point with a width of 35 to 50 feet, depending on the pipe diameter. Space requirements for coiled pipe are considerably less. Larger pipe sizes require larger and heavier construction equipment which needs more maneuvering room (though use of PE minimizes this). The initial pipe side “exit” location should be about 50’ W x 100’ L for most crossings, up to 100’ W x 150’ L for equipment needed in large diameter crossings.
• Obtain “as-built” drawings based on the final course followed by the reamer and the installed pipeline. The gravity forces may have caused the reamer to go slightly deeper than the pilot hole, and the buoyant pipe may be resting on the crown of the reamed hole. The as-built drawings are essential to know the exact pipeline location and to avoid future third party damage.