Horizontal Directional Drilling (HDD) — Safe Work Method Statement
Safe Work Method Statement for horizontal directional drilling (under-boring) to install conduits and pipes beneath roads, driveways and waterways, covering service location, rig set-up, pilot bore, reaming, pullback and drilling fluid management.
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Horizontal directional drilling (HDD) lets you install conduit and pipe without open trenching, but the bore path is blind and runs through ground already crowded with gas, electrical, water and telecommunications assets. A bore head striking a high-voltage cable or a gas main is the hazard that kills and injures HDD crews. HDD is usually High Risk Construction Work because it takes place where powered mobile plant is moving, often on or beside a road in use, and frequently near energised electrical services and pressurised gas mains. Entry and exit pits deeper than 1.5 metres add trench HRCW. A SWMS is required for each of these triggers.
Service location must be done in layers: lodge a Before You Dig Australia (BYDA) enquiry, get the asset owners' plans, have a competent locator electronically trace the route, then expose every service the bore will cross or run close to by non-destructive (vacuum or hand) excavation so its actual depth is confirmed, not assumed. Asset owners set their own clearance and supervision requirements, and some require a standby officer for crossings of major gas or high-voltage assets. The bore path design must keep clearances from exposed services, and the locator must track the head at each rod and compare depth against the plan.
Rig-specific hazards include entanglement in the rotating drill string and vice, high-pressure drilling fluid lines, rod handling, and the rig becoming energised if the head contacts a live cable. Use the rig's electrical strike detection system, deploy equipotential ground mats at the rig and the locator's position, and keep everyone off the drill string while it rotates. Drilling fluid can surface unexpectedly (frac-out or inadvertent returns) into roads, basements, drains or waterways, so the SWMS needs a containment and clean-up plan.
There is no single national HDD operator licence, but operators and locators must be trained and competent on the specific rig and locating equipment, and traffic controllers need the accreditation required by your state or territory road authority. Check your state or territory regulator and the road authority for permit requirements.
Customise this template with the bore length and design depth, the BYDA reference and asset owner conditions, the list of services potholed and their confirmed depths, the rig make and electrical strike system, the drilling fluid product and SDS, the traffic guidance scheme reference, and the frac-out response and spill kit location.
Personal Protective Equipment
High Risk Construction Work Types
- •Work in or near a shaft or trench deeper than 1.5 metres, or a tunnel
- •Work on or near pressurised gas distribution mains or piping
- •Work on or near energised electrical installations or services
- •Work on, in or adjacent to a road, railway or other traffic corridor in use by traffic
- •Work in an area with movement of powered mobile plant
Risk Assessment
1.Service location, potholing and bore path design
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Bore head strikes an unlocated or mis-located underground service | Catastrophic | Lodge a BYDA enquiry and obtain plans from every asset owner before work. Competent locator electronically traces and marks all services along the bore path. Expose every service crossing or within the asset owner's clearance zone by vacuum or hand excavation and record actual depth. Design bore profile to maintain asset owner clearances from exposed services. Do not start the bore until the supervisor has signed off the bore plan. | Moderate | Supervisor / Locator |
| Damage to services during potholing | High | Pothole by non-destructive excavation only. No mechanical excavation within the clearance distance set by the asset owner. Asset owner standby officer present where the asset owner requires it. | Low | NDD Operator / Supervisor |
2.Site set-up, traffic control and rig positioning
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Workers struck by road traffic | Catastrophic | Set up traffic control to an approved traffic guidance scheme before plant arrives. Accredited traffic controllers where flagging is required. Locator walking the bore path stays inside the delineated work zone; where the path crosses live lanes, stop or divert traffic while tracking. | Moderate | Supervisor / Traffic Controller |
| Rig or support truck rolls or tips on uneven or soft ground | High | Position rig on firm, level ground, clear of excavation edges. Deploy outriggers and stakedown anchors per manufacturer. Spotter used for all reversing. Exclusion zone around the rig marked with barriers. | Low | Rig Operator |
| Rig becomes energised after a strike on a live electrical cable | Catastrophic | Test the rig's electrical strike alarm at set-up. Lay equipotential ground mats at the operator station and connect to the rig per manufacturer. Locator stands on their own mat or keeps clear of the rig. If the strike alarm activates: operator stays on the mat, nobody touches the rig, clear the area and contact the asset owner. | Moderate | Rig Operator / Supervisor |
3.Excavation of entry and exit pits
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Pit wall collapse onto a worker | High | Keep pits as shallow as practicable. Pits deeper than 1.5 m are shored, benched or battered to suit ground conditions before entry. Spoil kept at least 1 m from pit edge. Pits barricaded and covered when unattended. | Low | Supervisor / Plant Operator |
| Falls into open pits by workers or the public | Moderate | Pits fenced with mesh barriers and lit at night when adjacent to footpaths or roads. Steel plates rated for traffic loads used where pits sit in trafficable areas. | Low | Supervisor |
4.Pilot bore and tracking
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Entanglement in rotating drill string or rod vice | Catastrophic | Nobody within the drill string exclusion zone while rotating or thrusting. Never step over the drill string. Rod loading only with rotation stopped and the operator's controls neutral. Rig guards and emergency stops tested daily. | Low | Rig Operator / Offsider |
| Bore deviates towards a known service | High | Locator reads head depth and pitch at every rod and calls readings to the operator. Compare against the bore plan; stop and correct if the head is within the clearance zone of any service. Record readings on the bore log. | Moderate | Locator / Rig Operator |
5.Reaming and product pullback
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Reamer or swivel failure releasing stored energy | High | Use reamers, swivels and pulling heads rated above the rig's maximum pullback force. Inspect shackles and weak links before pullback. Exclusion zone at exit pit while pulling; nobody stands in line with the product string. | Low | Rig Operator |
| Manual handling of rods, reamers and product pipe | Moderate | Use the rig's rod loader. Lift reamers with plant or two-person lifts with mechanical aids. Pipe rollers used to support product during pullback. | Low | Crew |
6.Drilling fluid management
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Frac-out or inadvertent returns into a road, drain, basement or waterway | High | Monitor fluid returns and pressure throughout drilling. Walk the bore path to watch for surfacing fluid. If returns are lost or fluid surfaces: stop pumping, contain with sandbags and sediment barriers, vacuum up, and notify the supervisor. Spill kit and vacuum truck available on site. | Moderate | Rig Operator / Supervisor |
| Injury from high-pressure fluid lines or skin contact with additives | Moderate | Inspect high-pressure hoses and fittings daily; whip checks on connections. Depressurise before breaking any connection. Wear gloves and eye protection when mixing; follow the additive SDS. | Low | Mud Mixer / Offsider |
7.Demobilisation and reinstatement
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Unsafe disposal of drilling fluid and spoil | Moderate | Collect spent fluid in a vacuum truck and dispose at a licensed facility. Do not discharge to stormwater. | Low | Supervisor |
| Backfilled pits subside or leave trip hazards | Moderate | Backfill and compact pits in layers. Reinstate surfaces to the road authority or property owner specification. Remove traffic control only after the site is safe. | Low | Crew / Supervisor |
Relevant Codes of Practice
Worker Acknowledgement
By signing below, I confirm that I have read, understood and agree to comply with this Safe Work Method Statement.