Guided Boring Pipe Jacking Works Safe Work Method Statement

Preventing service strikes during guided boring requires multi-layered approach combining comprehensive service location, accurate drilling guidance, and continuous monitoring throughout operations. Start with Dial Before You Dig plans minimum 5 working days before drilling obtaining current utility information for project area. Recognize plans show service locations with inherent accuracy limitations (typically ±0.5 to 1 metre) and services may not be at documented depths. Conduct physical service location using electromagnetic cable and pipe locators for metallic services (power, telecommunications, metallic water/gas) and ground-penetrating radar for non-metallic services (plastic pipes, PVC conduits). Mark all detected services on ground surface. Critically, conduct potholing (hand excavation or vacuum excavation) at regular intervals (every 20 metres recommended) and at all service crossing points to physically expose and verify service depths and positions - potholing is the only certain method to confirm service locations. For high-risk services including high-voltage power or gas transmission mains, engage service authority representatives for location verification and drilling supervision. Design bore path maintaining minimum clearances from located services (300-500mm typical, larger for critical services). Use accurate downhole guidance systems providing real-time drill head position data with ±50-100mm accuracy for small-diameter HDD. Brief drilling operators thoroughly on service locations, required clearances, and monitoring requirements. During drilling, continuously monitor guidance data verifying bore path alignment remains within designed tolerances and clearances from services are maintained. Implement proximity detection systems if available that alert when drill head approaches buried services. If unexpected resistance encountered, drill behavior changes, or guidance indicates path deviation, immediately stop drilling and investigate - never force drill through unexpected obstructions. Establish service strike emergency procedures including immediate equipment shutdown, area evacuation if gas or electrical services struck, notification of emergency services and utility authorities, and establishment of safety perimeters. Even with comprehensive location procedures, service strikes occasionally occur due to plan inaccuracies, unmarked services, or drilling deviations - robust emergency response procedures minimize consequences when strikes occur. The combination of thorough service location, accurate guidance technology, operator training, continuous monitoring, and established response procedures creates defense-in-depth approach effectively preventing most service strikes and managing consequences when strikes do occur.

Drive and reception shafts used in pipe jacking operations typically meet confined space criteria requiring comprehensive entry controls under Australian WHS regulations. Assess each shaft against confined space definition: does it have restricted entry/exit (typically yes for shafts accessed by vertical ladders), is it designed for continuous human occupancy (no - shafts are temporary work spaces), does it present atmospheric hazards or other risks (typically yes from soil decomposition, possible contaminated ground, engulfment from collapse or flooding). Most pipe jacking shafts 2-6 metres deep meet confined space criteria. Before any shaft entry, complete confined space entry permit documenting hazards, atmospheric test results, control measures, emergency procedures, rescue equipment, and worker assignments. Conduct atmospheric testing using calibrated 4-gas detector measuring oxygen (must be 19.5-23.5%), combustible gases (below 5% LEL), hydrogen sulphide (below 10 ppm), and carbon monoxide (below 30 ppm). Test atmosphere at multiple depths as gases stratify in shafts. If atmosphere fails any parameter, provide forced ventilation using portable blowers achieving minimum 6 air changes per hour and retest until safe atmosphere confirmed. For extended shaft occupancy during pipe jacking operations (workers may spend hours in shafts operating jacking equipment or excavating), maintain continuous forced ventilation and periodic atmospheric retesting (every 2 hours minimum). Assign trained standby person stationed at shaft entrance maintaining continuous visual or voice contact with workers in shaft throughout entry. Standby person monitors atmospheric conditions, maintains communication, and can initiate emergency procedures but must not enter shaft for rescue without proper breathing apparatus and backup personnel. Require workers entering shafts to wear full-body harnesses with retrieval attachments enabling emergency extraction by standby person without requiring entry. Establish maximum shaft occupancy based on size and ventilation - typically limit to 1-2 workers in standard jacking shafts. Install adequate lighting in shafts ensuring workers can see hazards and perform tasks safely. Provide safe access systems including ladders meeting standards (AS 1657) with secure top and bottom fixing, three points of contact, and adequate extension above shaft opening. Implement weather monitoring requiring immediate shaft evacuation if heavy rain forecast - shaft flooding creates serious drowning hazard particularly in high groundwater areas. Brief all workers on emergency procedures including shaft evacuation routes, communication methods, and rescue procedures. Maintain rescue equipment immediately accessible including retrieval lines, emergency breathing apparatus for rescuers, communication devices, and first aid equipment. Document all shaft entries including entry and exit times, workers involved, atmospheric test results, and any incidents or unusual conditions. Review confined space procedures regularly and after any incidents ensuring continuous improvement. The combination of atmospheric testing, forced ventilation, standby persons, emergency rescue capability, and comprehensive entry permits provides protection framework for inherently hazardous confined shaft entry work during pipe jacking operations.

Drilling fluid management during HDD operations requires balanced approach maintaining bore stability while preventing environmental contamination from fluid escapes (frac-outs) to surface. Select drilling fluid type appropriate to ground conditions and environmental sensitivity: bentonite (clay-based) fluids provide excellent bore stability in most soils but present higher environmental impact if released; polymer-based synthetic fluids offer reduced environmental impact in sensitive areas though typically at higher cost. Mix drilling fluid to manufacturer's specifications achieving proper viscosity, gel strength, and fluid properties for ground conditions. Establish drilling fluid circulation system with adequate mixing capacity, pumping pressure and volume capability, and settlement/filtration systems for cleaning and recirculating returned fluid. Monitor drilling fluid parameters throughout operations measuring injection pressure (typically 300-700 kPa depending on depth and ground), circulation rate (litres per minute based on bore diameter), and return volume. Critical monitoring point is fluid return percentage: if returns drop below 80% of injection volume, indicates fluid loss into ground potentially indicating frac-out conditions or bore instability. Establish action levels: 20% fluid loss triggers investigation and monitoring intensification, 30% loss requires work cessation and corrective action before proceeding. If significant fluid loss detected, implement corrective measures including reducing drilling pressure, adjusting fluid properties to improve bore wall sealing, allowing bore to stabilize before continuing, or grouting unstable zones. Conduct visual ground surface inspections along bore path during drilling watching for signs of drilling fluid reaching surface (wet ground, mud pools, vegetation coating). If frac-out detected, immediately reduce drilling pressure, implement surface containment using absorbent materials or berms preventing fluid migration, recover surfaced fluid using vacuum equipment or manual collection, and notify environmental authorities if significant volumes released or sensitive receptors affected. For environmentally sensitive areas (near waterways, wetlands, heritage sites), implement enhanced monitoring including pre-drilling visual inspections documenting baseline conditions, continuous surface observation during drilling by dedicated environmental spotter, reduced drilling pressures minimizing frac-out probability, and immediate response capability with containment equipment staged at site. Establish drilling fluid containment at drill entry and exit points using settlement tanks, filter systems, or earthen pits capturing returns and preventing discharge to stormwater systems. Some projects require closed-loop systems recirculating all drilling fluid without discharge. Dispose of used drilling fluid according to waste classification: clean bentonite slurry from non-contaminated sites may allow land application or disposal to general landfills; contaminated drilling fluid or fluid containing chemical additives may require disposal at licensed waste facilities. Conduct post-drilling environmental inspection along entire bore path documenting any frac-outs occurred, cleanup actions taken, and environmental impacts observed. For projects in highly sensitive areas or with significant frac-out risks, consider environmental monitoring including pre and post-drilling water quality testing, ecological assessments, and long-term monitoring if contamination occurred. Maintain drilling fluid records documenting volumes mixed, injection and return volumes, any losses detected, frac-out incidents and responses, and disposal information - these records demonstrate environmental due diligence and support incident investigations if environmental authorities inquire about drilling activities.

Guided boring and pipe jacking operations require specialized qualifications addressing technical competencies and safety requirements. Drilling rig operators must hold current operator qualifications for specific equipment being used - many equipment manufacturers provide operator training courses covering rig operation, guidance system use, drilling procedures, troubleshooting, and maintenance. Some states/territories may require high-risk work licenses for operating certain large drilling plant. Operators need demonstrated competency in drill rig setup and operation, downhole guidance system operation and interpretation, drilling parameter monitoring and adjustment, service strike avoidance procedures, and emergency response including service strike response. Guidance operators (may be separate from drill rig operator on larger projects) require training in specific guidance systems being used (walkover locating, wireline systems, gyroscopic systems) including equipment setup and calibration, real-time position monitoring, data interpretation, and steering corrections. All workers require confined space entry training meeting AS 2865 requirements if they will enter drive shafts, reception shafts, or pipe sections during operations - training covers atmospheric testing, entry permits, emergency procedures, and rescue. This qualification should be current within 2-3 years and include both theory and practical components. Workers conducting service location require competency in electromagnetic cable/pipe location, ground-penetrating radar operation and interpretation, understanding of utility plans, and potholing supervision. Some utility detection equipment manufacturers provide training courses leading to competency certification. General construction induction (White Card) is mandatory baseline requirement for all workers on construction sites. First aid training valuable particularly for workers in remote locations or working with confined space hazards - someone on crew should hold current first aid qualification. For pipe jacking operations, workers require training in hydraulic jacking frame operation, pipe installation procedures, excavation methods for ground removal from advancing pipes, and pipe welding or jointing techniques depending on pipe type. All workers need safety training covering specific hazards of guided boring and pipe jacking including service strike hazards and response procedures, confined space entry requirements, drilling equipment hazards and exclusion zones, ground stability and collapse risks, and emergency evacuation procedures. Provide equipment-specific training for all specialized equipment workers will operate ensuring competency in safe operation, pre-start inspection, and basic troubleshooting. Implement supervised work program for newly trained workers: pair inexperienced operators with experienced personnel for initial projects, conduct increased supervision and monitoring of work quality, provide feedback and coaching, and progressively increase responsibility as competency demonstrated. Maintain comprehensive training records documenting each worker's qualifications including equipment operator certifications and expiry/renewal dates, confined space entry training and currency, service location competency, first aid qualifications, safety training completion dates, and equipment-specific training. For complex or specialized boring projects (large-diameter pipe jacking, environmentally sensitive areas, congested utility environments), consider engaging specialist contractors with extensive project experience, demonstrated track record, and comprehensive training programs. Review contractor qualifications and competency verification processes during contractor selection. Conduct pre-project meetings verifying all personnel assigned to project hold required qualifications and competencies for roles they will perform. The technical complexity of guided boring and pipe jacking combined with significant safety hazards from service strikes, confined spaces, and equipment operations makes comprehensive training and demonstrated competency essential for all personnel conducting this specialized construction work.