Pilot Bore and Tracking

Purpose

Drill the pilot bore on the planned path, hold clearance from every existing utility, and record where the bore actually went. The bore log is the record the owner, the next crew and every future locator will rely on. A bore log that does not match the ground is worse than none.

When to Do It

• Trigger: bore planning and rig setup are complete (UG-05).
• Prerequisites: valid locate ticket, every crossing potholed (UG-04), locator calibrated, strike system tested, tailboard held.
• Previous step: UG-05 Bore Planning and Rig Setup.
• Next step: UG-07 Reaming and Pullback.

Roles

• Drill operator: runs the rig, steers on the locator operator’s calls, and stops on any warning sign.
• Locator operator: walks over the bore head and reads depth, pitch, roll (clock position) and heading.
• Spotter: watches open potholes at each crossing and calls the bore head as it passes.
• Foreman: owns the bore log, the emergency plan and the decision to restart after any stop.

Equipment and Materials

• Horizontal directional drill with drill rods.
• Drill head with sonde (transmitter).
• Walkover locator calibrated to the sonde.
• Radios between the drill operator, locator operator and spotter.
• Bore log, on paper or electronic.

Safety

Procedure

Hold Points

Records to Keep

• The complete bore log: rod number, distance, depth and pitch at every reading.
• Every deviation from the planned path, with the reason.
• Photos of the bore head passing each crossing.
• Any stop, warning sign or suspected strike, and who cleared the restart.
• Damage reports and owner notifications for any facility damaged, however minor.

Common Mistakes

• Skipping readings. The bore log stops matching the ground, and the as-built is wrong forever.
• Ignoring locator interference. Rebar, traffic loops and overhead power can throw off depth readings.
• Drilling through a crossing without confirmation. Stop and confirm every time.
• Shallow cover under driveways. Check cover where grade changes, not only at the crossings.

Standards and References

• CGA Best Practices: directional drilling and damage prevention.
• 49 CFR Part 196: excavation near gas and hazardous liquid pipelines, including reporting any pipeline damage to the operator and calling 911 on a release.
• Locator manufacturer instructions.
• Owner bore log requirements.

On the Map

• Drill Head and Sonde: the slant-face bit with a transmitter reporting depth, pitch and roll.
• Walkover Locator: the receiver carried over the bore head to read position and steer.
• Directional Bore Path: the planned and actual pilot-bore path between the entry and exit pits.
• Gas Main: the crossing where a strike is most dangerous.
• Sewer Main and Lateral: laterals are often unmarked and a crossbore risk.
• Underground Power: the crossing where an electrical strike can energize the rig, rods, fluid and ground.
• Water Main: a common crossing; confirm clearance against the pothole data before you pass it.
• Drill Rods: added one at a time behind the head; each rod is a common reading interval in the bore log, unless the owner sets another (step 3).

Related Tools

• Bore Planning Helper: sketch the planned entry path and setback before you drill. Track the actual path with the walkover locator.