20140402 excavation procedure

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Policy Standards Procedures Tools, Plans and Docs Procedure Excavation QCOPS-BX00-HSS-PCE-000007 Rev 2 February 2014 Uncontrolled when printed Upstream Operations

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Excavation procedure

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Page 1: 20140402 Excavation Procedure

Policy

Standards

Procedures

Tools, Plans and Docs

Procedure Excavation

QCOPS-BX00-HSS-PCE-000007

Rev 2

February 2014

Uncontrolled when printed

Upstream Operations

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Table of Contents

FOREWARD 5 1.1 Scope of Document 5

1.2 Document Revisions and Approval 5

1.3 Distribution and Intended Audience 5

2.0 RESPONSIBILITIES 5

3.0 PLANNING 7 3.1 Risk Management 7

3.1.1 Hazard Identification 7 3.1.2 Risk Assessment (Safe Work Method Statement) 8 3.1.3 Risk Control 9 3.1.4 Design 9 3.1.5 Consultation 10

3.2 Permit to Work (PTW) for Excavation 10

3.3 Identification of Services 10

3.3.1 Site Survey of Area to be Excavated 10 3.3.2 QGC Crossing Process 11 3.3.3 Limits of Approach 11

3.4 Task Rescue Plans 11

3.5 Planning for Backfilling 12

4.0 WORK ENVIRONMENT 13 4.1 Adjacent Work Activities 13

4.2 Ventilation, Harmful Gases and Fumes 13

4.3 Barriers, Barricades and Signage 13

4.4 Public Access 14

4.4.1 Work Near Public Roads or Footpaths 14

4.5 Movement of Vehicles and Plant Near or Over Excavations 14

4.6 Work at Night/Lighting 15

4.7 Adjacent Buildings or Structures 15

4.8 Site Contamination 16

4.8.1 Acid Sulphate Soils 16

5.0 PLANT & EQUIPMENT 16 5.1 Selection and Transport of Excavation Plant and Equipment 16

5.1.1 Selection 16 5.1.2 Transport 16 5.1.3 Specifications 17

5.2 PPE 17

6.0 TRAINING & COMPETENCE 17 6.1 Training Requirements 17

6.2 Engineering Resource 17

7.0 SAFE WORK PRACTICES 18 7.1 Supervision 18

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7.2 JSEA/Step Back 18

7.3 Installed/Live Services 18

7.3.1 Gas Detection 18 7.3.2 In-Field Identification of Live Services 18 7.3.3 Exposure of Live Services 19 7.3.4 Water Excavation Equipment 19 7.3.5 Mechanical Excavation Near Live Services 19 7.3.6 Excavation Near Underground or Overhead Electrical Hazards 19 7.3.7 Service Identification Markers 19 7.3.7.1 Colour Codes for Service Identification 20 7.3.8 Temporary Services 20 7.3.9 Placing Electrical Cables 20

7.4 Access and Egress 20

7.5 Ground Support 21

7.5.1 Depth Less Than 1.2 metres 21 7.5.2 Depth 1.2 Metres or Greater 21 7.5.3 Design 21 7.5.4 Shoring 22 7.5.5 Benching and Battering 22 7.5.6 Narrow Trenches, Ditches and Small Holes 22

7.6 Fall Prevention and Falling Objects 22

7.6.1 Fall Prevention 22 7.6.2 Falling Objects 23 7.6.3 Barricades and Handrails 23 7.6.4 Walkways 23

7.7 Excavated Material 23

7.8 Inspections 24

8.0 ENVIRONMENTAL AND COMMUNITY ISSUES 24 8.1 Water Management 24

8.2 Waterlogged Ground 24

8.3 Erosion from Adverse Weather 25

8.4 Cultural, Environmental and Archaeological Issues 25

9.0 COMPLETION OF EXCAVATION WORKS 25

9.1 Filling Around Services 25

9.2 Completion of Works 26

10.0 AUDIT AND MANAGEMENT REVIEW 26

Appendices Table of Contents

APPENDIX A – Document Distribution Record (RACIE Sheet) 27

APPENDIX B – Definitions and References 29

APPENDIX C – Change History 35

APPENDIX D – Feedback Form 37

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FOREWARD

1.1 Scope of Document

The purpose of this document is to:

provide the operational controls required for performing excavations in accordance with safe working practices;

define the responsibilities of nominated persons; and

define approvals required for excavation work.

It applies to all excavation work conducted under the QGC Operations PTW process (Refer to QCOPS-BX00-HSS-PCE-000002), including:

ground penetrations

open excavations; and

trenching and shoring activities.

This procedure has been developed to comply with applicable BG and QGC Standards and is to be used in conjunction with all applicable legislation, Codes of Practice, and Australian Standards.

Note: Local legislation may contain additional requirements that must also be applied in work activities and risk assessments.

1.2 Document Revisions and Approval

This document bears a revision status identifier which will change with each revision. All revisions to this document (after approval and distribution) are subject to review and endorsement by the same functions as the original.

1.3 Distribution and Intended Audience

This document is intended for Operations members as well as other QGC stakeholders. The document will be made available on the intranet. This document will be updated during subsequent lifecycle stages and changes communicated as applicable.

2.0 RESPONSIBILITIES

The following responsibilities apply for all personnel undertaking activities covered by this document.

Role Responsibility

General Manager Upstream Operations/

Upstream Projects General Managers

a) Ensure that all aspects of the QGC Operations Excavation Procedure are implemented, resourced and monitored.

b) Ensure emergency response persons are trained and competent to perform emergency rescue from a work situation

c) Ensure the PTW system, which includes Excavating as a high risk activity is effective in operation, documented, and adequately resourced in material, personnel, and skills.

d) Ensure processes for monitoring, auditing and reviewing the Excavation procedure are established and maintained.

Field Operations Manager / Project Field Area Manager

a) Maintain a PTW system that covers Excavation, to ensure that work will be undertaken on QGC work sites with adequate control measures in place to reduce risk to ALARP.

b) Ensure that identified non-compliances are reported, thoroughly investigated and remedial actions closed out.

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Role Responsibility

c) Facilitate Excavation consultation and communication processes across QGC operations for review of the PTW System across all levels. Ensure Management of Change Processes are in place where required.

d) Ensure that information, instruction, training and supervision of all personnel are provided to enable them to perform their work such that their exposure to the hazards on QGC sites is as low as reasonably practical.

e) Appoint Endorsing Authorities for high risk tasks involving Excavation.

f) Implement a process to ensure the design, modification, purchase and/or hire of plant, equipment and PPE used for Excavation complies with all applicable statutory requirements and this procedure.

Area Superintendent a) Ensure Competent Personnel are appointed to manage the Excavation procedure for the site.

b) Ensure that there is a system to regularly inspect and maintain in proper working condition all plant, equipment or PPE used for Excavation on QGC sites.

c) Ensure the development, maintenance and regular review of hazard and equipment registers for the site that support the Excavation procedure. This equipment will be tested and certified for use by licensed and Competent Persons.

d) Ensure emergency response people, systems and processes are in place for the site. This includes appointing appropriately trained and Competent Personnel and conducting a full scale emergency response drill at least annually.

e) Auditing the site for compliance to the Excavation procedure on a regular basis.

f) Ensure that all employees and contractors using the Excavation procedure are informed of its requirements; are trained and competent and understand the need for compliance.

g) Ensure the Excavation procedure is understood and complied with by all employees and contractors, including monitoring the effectiveness of the Excavation procedure within their work area.

Area Owner In addition to Area Owner responsibilities detailed in the PTW procedure, ensure that all excavation tasks in their area are monitored during the course of the work as per the requirements of this procedure.

Permit Holder or Team Leader

In addition to the Permit Holder or Team Leader responsibilities detailed in the PTW procedure, ensure all excavations work undertaken complies with the conditions and controls set out in this procedure.

Work Party Member In addition to the Work party Member responsibilities detailed in the PTW procedure, ensure individual familiarity with the approved PTW content, including Excavation procedure requirements and comply whilst completing the task.

Permit Issuer In addition to the Permit Issuer responsibilities set out in the PTW procedure

a) Ensure that all identified excavation work is undertaken under the PTW system and that authorisations are obtained from Excavation Endorsing Authorities when required.

b) Ensure all controls necessary for safe Excavation work are clearly documented in the SWMS and PTW and its supporting documentation (Certificates and plans).

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Role Responsibility

Endorsing Authority In addition to the Endorsing Authority responsibilities set out in the PTW procedure:

a) Certify on the Excavation Certificate that all controls are appropriate for the task and as per the requirements of this procedure.

b) Provide advice to the workforce on undertaking safe excavations.

HSSE Manager a) Ensure the Excavation procedure complies with BG Group, QGC and Australian Regulatory requirements.

b) Ensure the Excavation procedure is audited as per the audit schedule and monitor close out of non-conformances.

c) Provide advice on Excavation best practice for continuous improvement.

d) Ensure this procedure is reviewed and kept-up-to-date. e) Ensure incident investigations are conducted and corrective

actions implemented for any incident involving Excavation. f) Facilitate Excavation consultation and communication processes

across QGC operations for review of the PTW System across all levels. Ensure Management of Change Processes are in place where required.

Permit and Compliance Coordinator

a) Provide guidance on PTW system, including any proposed temporary deviations to all parties as required. This includes oversight of the Excavation procedure in line with PTW procedural principles.

b) Ensure that the Excavation procedure is reviewed regularly to ensure compliance with regulatory and QGC standards, policy and procedural requirements.

c) Verify all identified excavation work is undertaken under the PTW system and is consistently applied across all parts of the operation.

d) Ensure the Excavation procedure is audited as per the audit schedule and monitor close out of non-conformances.

3.0 PLANNING

3.1 Risk Management

3.1.1 Hazard Identification

As a minimum, the following hazards must be considered when planning excavation activities:

underground and overhead services, including gas, water, sewerage, telecommunications, electricity, chemicals, and fuel or refrigerant in pipes or lines;

the fall or dislodgement of earth or rock;

falls and falling objects;

inappropriate placement of excavated materials, plant or other loads;

the instability of any adjoining structure caused by the excavation;

the instability of the excavation due to persons or plant working adjacent to the excavation;

the presence of or possible inrush of water or other liquid;

road traffic obstruction caused by the excavation or trench;

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a hazardous atmosphere in the excavation or trench due to:

o gas or flammable liquids from above-ground leaks or spills;

o vehicle/machinery exhaust fumes;

o poor ventilation; or

o oxygen depleting soils

vibration;

lifting and handling hazards (e.g. from scaffolding being lowered into the excavation);

buried munitions;

confined space hazards;

health and ergonomic risks associated with manual excavation techniques;

welfare and sanitation risks associated with remote/temporary worksites, and

contaminated soil.

Controls for all hazards identified must be recorded on the SWMS.

Ground Conditions In conjunction with the planning process outlined in the Permit to Work Procedure (QCOPS-BX00-HSS-PCE-000002), before any mechanical excavation works take place, the ground conditions must be assessed. This can be achieved through boreholes, trial pits or information from previous or current work in the area. If none of the above is possible, the ground conditions must be examined when excavation commences.

3.1.2 Risk Assessment (Safe Work Method Statement)

Before any excavation activity occurs, a Competent Person must perform a risk assessment (SWMS) as part of the work planning process. The SWMS must:

consider all reasonably foreseeable hazards; and

determine the required control measures for these hazards.

All SWMS must be developed in accordance with QGC Safe Work Method Statement Procedure (QCOPS-BX00-HSS-PCE-000005).

The SWMS must be retained with the PTW documentation for the excavation and may be used for subsequent excavations at the same site if the conditions remain constant and unchanged from the development of the original SWMS.

The SWMS must consider the reason for the excavation and all applicable hazards associated with the work and the specific work site. In addition to the general excavation hazards identified in Section 3.1.1, the SWMS must consider the following job-specific factors:

local site conditions, including access, ground slope, adjacent buildings and structures, water courses (including underground) and trees;

depth of the excavation;

soil properties, including variable soil types, stability, shear strength, cohesion, presence of ground water and the effect of exposure to the elements;

proximity of live services to the excavation and minimum approach distances;

potential for sewerage seepage or methane gas/vapour migration;

the condition of the soil substrate;

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fractures or faults in rocks, including joints, bedding planes, dip and strike directions and angles, and clay seams;

any specialised plant or work methods required (for example ground support, removal of material below the live service);

the method(s) of transport, haul routes and disposal;

exposures that may occur, such as noise or UV rays;

the number of people involved;

the need to enter/work in the excavation;

the possibility of unauthorised access to the work area;

local weather conditions, and

the length of time the excavation or trench will be open.

For excavations and trenches across roads, the control of traffic and pedestrians must be considered in the SWMS and consideration must be given to preparing a traffic management plan, for approval by the Local Road Authority if required.

Confined Spaces

If the SWMS identifies the potential for the excavation to become a confined space (e.g. concentrations of airborne contaminants in the trench that could lead to impairment, loss of consciousness or asphyxiation), a Confined Space Identification Risk Assessment (QCOPS-BX00-HSS-FRM-000010) must be completed.

If this assessment confirms the presence of a confined space, the requirements of the QGC Confined Space Entry Procedure (QCOPS-BX00-HSS-PCE-000003) must be met in addition to the requirements of this procedure.

3.1.3 Risk Control

Controls for excavation activities must be selected according to the hierarchy of controls. Wherever possible, the requirement to excavate should be eliminated. If no single control is sufficient to reduce excavation risks to the lowest level reasonably practicable, a combination of controls must be used.

Based on the outcome of the risk assessment, all necessary safety systems and equipment, including PPE, must be provided and an emergency plan must be prepared, commensurate with the risk.

Most Effective

Least Effective

Elimination Can the need for excavation be avoided by installing cables or pipes above ground in pipe racks, cable racks or existing culverts?

Substitution Can an alternate method such as moling, directional drilling or other non-destructive pipe-laying technique be used instead of open excavation?

Engineering/ Isolation Can barricades, barriers, fencing or handrails be put in place to prevent the risk of falls?

Can benching, battering or shoring the sides of an excavation reduce the risk of ground collapse?

Administrative Controls Can procedures, SWMS, PTW, emergency plans, toolbox talks, JSEAs and regular inspections minimise exposure?

Personal Protective Equipment

Can hard hats, hearing protection and high-visibility vests protect workers from excavation hazards?

3.1.4 Design

Designs must optimise the layout, constructability, operability, maintainability and accessibility of facilities, while at the same time minimising the requirement for excavation or trenching during construction and subsequent operation.

Excavations and trenches must be sited to minimise excavation risks to people, plant and the environment, including the possibility of damaging other services in the vicinity.

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Excavations and any supports must be designed in accordance with acceptable engineering principals and standards.

3.1.5 Consultation

Personnel involved in excavation activities must be consulted during development of the SWMS and JSEA, and selection of the required controls.

3.2 Permit to Work (PTW) for Excavation

A PTW is required for all excavations deeper than 300mm in brownfield areas.

A PTW is required for excavations less than 300mm in depth unless:

the excavation has been appropriately risk assessed and has been approved by the Area Owner as a one-off, low-risk activity; or

the task is listed on the site’s Approved Task List (ATL).

The PTW must:

identify the reason for the excavation;

list the controls required to safely manage both the excavation and movement around and into the excavation; and

identify the nominated competent safety observer/spotter.

If personnel will be entering an excavation that has been determined a confined space (refer to Section 3.1.2), a Confined Space Certificate (QCOPS-BX00-HSS-CER-000001) must be issued with the PTW.

If excavation will occur within the 15 metre pipeline exclusion zone, the relevant QGC Area Superintendent or delegate must be consulted and Guidelines for work near QGC Pipelines (QCOPS-OPS-HSS-GDL-000001) must accompany the PTW application.

For all Brownfield excavations of 1.2m or greater, a QGC appointed Excavation Endorsing Authority must review and approve/endorse the PTW application and supporting documentation. An Endorsing Authority is not required for driving stakes, auguring, boring or piling if there is no risk of a person entering the excavation.

Third-party service owners must be consulted to obtain approval and determine additional controls required when working in the vicinity of their services.

The PTW can only be issued when the SWMS and the Excavation Certificate (QCOPS-BX00-HSS-CER -000003) are complete and the control measures are either in place or ready to be installed as the excavation proceeds.

Note: Refer to Permit to Work Procedure (QCOPS-BX00-HSS-PCE-000002)

3.3 Identification of Services

3.3.1 Site Survey of Area to be Excavated

Before physical excavation work begins, the Permit Holder (or person applying for the permit) must initiate a thorough site or route survey to identify:

any overhead or underground services that may be affected;

the location, depth, size and capacity/rating of any underground pipes, cable or plant associated with the services; and

any restriction on trenching or excavation activities imposed by the owner of an underground service.

As a minimum, the survey must include:

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a Dial Before You Dig (DBYD) search completed with sufficient time to allow for any changes in the work program caused by the identified services (Submit DBYD requests at http://1100.com.au or phone 1100); and

a review of existing and proposed infrastructure in the QGC Geographical Information System (GIS) using MapMagic (http://mapmagic).

Particular attention should be given to investigation of secondary infrastructure that may have been buried with large assets such as fibre optic cables, anode cables, etc.

The results of this survey must be accurately recorded and documentation, including a map and coordinates of the area to be excavated, must be attached to the PTW. All survey information must be communicated to the work party before excavation work begins.

Any services identified in the field that were not identified on DBYD and MapMagic searches must be reported to the QGC GIS team.

3.3.2 QGC Crossing Process

The QGC Crossings Process must be followed for:

all excavations crossing QGC linear infrastructure (including trunklines, gathering lines and fibre-optic cable); and

all construction work that approaches within 15m of the extremities of any QGC linear infrastructure.

QGC construction contractors must obtain a QGC Crossing reference number before they submit the PTW request. A crossings application is not required; contact the Crossings Team via email to request the crossings reference number.

Third parties crossing QGC infrastructure must submit a crossings application and have approval to cross from the Crossings Team before they submit the PTW request.

Contact the QGC Crossings team at [email protected] and refer to Managing Crossings of QGC Infrastructure by Third Parties and QGC Contractors (QCLNG-BX00-CON-PCE-000012).

3.3.3 Limits of Approach

A limit of approach specifies the clearances required when working around underground services (and sometimes overhead services). The limits of approach for identified services must be confirmed by consulting the service owner, local legislation or guidance material, and must be reflected in the excavation PTW conditions.

The limits of approach for QGC underground gas and water services are built into the Excavation Certificate (QCOPS-BX00-HSS-CER -000003). Additional limits of approach must be included in Step G of the certificate (e.g. limits of approach for overhead power lines).

3.4 Task Rescue Plans

A specific Task Rescue Plan must be developed for any activity where a person is entering an excavation. This plan must be commensurate with the risks identified for the activity and must consider, as a minimum:

the nature of the hazard and possible emergencies;

the size and location of the place of work;

the number and mobility of persons at the workplace;

the safe and rapid evacuation of persons from an excavation;

emergency communications (including communication with service owners);

appropriate medical treatment of injured persons;

location of rescue equipment including shoring material;

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location of pumps;

gas monitoring equipment;

unplanned or unforeseen natural disasters such as electrical storms, floods, fire that may present a hazard to working operations;

the location of the nearest emergency services;

access for rescue vehicles and personnel;

map/aerial picture of area identifying valve locations; and

any other risks identified for the activity.

Control measures within the emergency plan must include:

development and communication of a warning system;

development and communication of safe and rapid evacuation procedures, including injured persons;

having trained personnel, commensurate with the level of risk, to oversee evacuation and rescue procedures until emergency authorities arrive;

appropriate medical treatment and evacuation of injured persons;

shutting down of work, including plant and electrical equipment;

provision of fire fighting and rescue equipment at appropriate locations; and

display of evacuation procedures in appropriate location(s) at the work area.

All excavation work party members must be made aware of the task rescue plan and how it relates to them.

3.5 Planning for Backfilling

Backfilling operations must be considered during the planning process to ensure that the operation is planned and conducted safely and efficiently while achieving the planned standards of compaction.

As a minimum, the following issues must be considered:

placement of material while personnel are in the excavation;

movement of machines above and around the excavation;

removal of shoring to ensure personnel not exposed to unsupported trench walls;

how the required compaction levels will be obtained;

vibration effects from compaction equipment;

exhaust gases from compaction equipment;

manual lifting of compaction equipment in and out of the trench; and

marking of services with underground marking tapes and surface markings as per local legislative requirements.

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4.0 WORK ENVIRONMENT

4.1 Adjacent Work Activities

Zone of Influence

A zone of influence must be determined and marked around each excavation. Heavy loads, including plant, vehicles, spoil piles and stored materials must not be operated or located in the Zone of Influence unless a Competent Person has designed the ground support system installed.

Vibrating Machinery

Vibrating or impact machinery must not be operated within the zone of influence when personnel are in the excavation.

Work Separation

Workers and work tasks in excavations must be sufficiently separated to avoid injury.

Workers must also be separated from active digging faces and active dumps to avoid being struck by:

falling material;

an excavator bucket; or

any part of the excavator within the excavator swing radius.

Working alone in an excavation is not permitted. There must be a dedicated spotter at all times.

4.2 Ventilation, Harmful Gases and Fumes

The task risk assessment (SWMS) must consider the potential for exhaust gases from equipment outside the excavation to enter the workings, and for exhaust gases from equipment inside the excavation to be not carried away from the work area by natural ventilation.

Where mechanical ventilation equipment is required to establish and maintain a safe environment, the equipment must be monitored regularly and have the controls, including any remote power supply, identified and tagged to prevent any unauthorised or accidental interference.

4.3 Barriers, Barricades and Signage

The perimeter of all excavations or trenches must be secured to prevent unauthorised access of personnel into the work area. Methods include:

barricades/barriers;

fencing; and

handrails.

Barriers or stop blocks must be installed where there is an identified risk of plant (e.g. cranes, dumpers, tip trucks, etc.) manoeuvring too close to the edge of the excavation and either affecting the stability of the edge or falling in.

Barriers must be:

made of substantial material (excavated material can be used);

at least 900mm high;

installed at least 1.0m from the edge of the excavation unless approved by a Competent Person; and

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installed outside of the zone of influence i.e. horizontal clearance equal to trench depth.

Webbing fences and hard warning tape are not acceptable barriers for fall protection and must only be used for pedestrian traffic management.

Trenches must be back filled as soon as practicable, or, as a minimum, covered with a substantial cover or barricaded. Trenches must not be left open overnight in vehicle or pedestrian traffic areas. When an excavation is opened exposing a buried asset, protection measures must be put in place to protect the asset from vehicle impact if identified as a risk during the Risk Assessment or deemed as required by the relevant Superintendent.

When an excavation is to be left open and unattended:

clear and sufficient signs must be posted at the entrances to the excavation to highlight the excavation hazard and any particular hazards encountered within the excavation (e.g. confined spaces);

adequate barriers must be in place to avoid danger to pedestrians and vehicles;

suitable lighting and reflective signage must be installed, where appropriate; and

the area must be regularly inspected.

4.4 Public Access

Particular care must be taken in and around areas where the general public may have access to an excavation:

In remote locations or where the general public may not have access, the Area Superintendent must review requirements for barricading and must ensure that adequate hazard demarcation and protection is provided.

For excavations in the public domain or within third-party property or land, the protective system must display the Principal Contractor’s contact details for reporting defective barriers or unsafe excavations.

4.4.1 Work Near Public Roads or Footpaths

Excavation and trenching works near public roads and footpaths must not put the public or workers at risk:

As a minimum, the barrier and signage requirements contained in the Queensland Manual of uniform traffic control devices Part 3: Works on roads must be complied with.

In addition, local legislation or guidance information may prescribe clearances and approvals required before working in the vicinity of roads or footpaths. Local council approvals or permits must be attached as supporting documentation to the QGC PTW.

4.5 Movement of Vehicles and Plant Near or Over Excavations

Vehicles and plant must not be brought alongside excavations or trenches unless:

it is essential to do so; and

a Competent Person has approved the movement.

If it is required to cross buried infrastructure with vehicles, approvals must be obtained from the relevant area and asset department if required. Refer to Guidelines for work Near QGC Pipelines QCOPS-OPS-HSS-GDL-000001.

If the excavation needs to be temporarily bridged, a Competent Person must determine the use and design of temporary bridging. When road plates are used for temporary bridging:

the trench sides must be stable or adequately supported (considering the anticipated traffic loading);

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no person must work or pass under a road plate unless traffic is halted;

the plate must be of sufficient length to be firmly supported for at least 600mm on each side of the trench and of sufficient width to provide a distance of at least 250 mm from the wheels of vehicles to the edge of the plate (or as determined by a Competent Person);

the thickness of the plate must be sufficient to support the range of traffic encountered;

ramps must be formed of a suitable material where the road plate is proud of the road surface;

consideration should be given to securing the road plates by pinning or sinking into the roadway when the site is not attended or when subject to frequent use by heavy vehicles;

appropriate ramp warning signs must be displayed;

they must be regularly inspected if the site is unmanned;

appropriate lifting and handling precautions must be taken to ensure that the road plates are transported, installed and removed safely; and

fabricated bridges must have engineering certification for load bearing capacity.

4.6 Work at Night/Lighting

Excavations must be sufficiently lit to:

make hazards visible;

conduct work tasks safely; and

safely evacuate the area in the event of an emergency.

Excavations in public areas and near permanent public access ways must have their edges illuminated. Battery operated flashing lights placed at intervals are usually sufficient.

In deeper excavations or during times of reduced visibility, lighting may be necessary to allow work to proceed safely. The lighting must be placed so that the level of illumination at the working area is not less than 200 LUX and access ways and working areas are free of glare and deep shadow.

Lighting must be guarded and installed to prevent damage and power leads must be protected from water ingress and mechanical damage. All electrical items must comply with the QGC Electrical Safety Procedures.

Further information can be found in:

AS/NZS 3012:2010 Electrical installations – Construction and demolition sites (Section 2.7 Lighting and luminaries)

AS 2293.1 – 2005 Emergency escape lighting and exit signs for buildings Part 1: System design, installation and operation (Section 5 Design of emergency escape luminaire installation)

4.7 Adjacent Buildings or Structures

Excavation work which is likely to impact on the stability and security (including stress cracks) on any part of a structure must not commence until adequate protection measures are employed to monitor and maintain the existing structural integrity of the asset.

Any excavation below the level of the footing of any structure or retaining wall that could affect the stability of the structure must be secured by a suitable ground support system unless the excavation is in stable rock, as determined by a Competent Person. Suitable supports for the structure may also be required.

In all cases, the Permit Holder must ensure that adjacent buildings or structures are not adversely affected by vibration or concussion during the excavation work. Precautions must be taken to ensure that

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buildings or structures containing equipment sensitive to shock and vibration are adequately protected if temporary relocation of the equipment is not possible.

Excavation work must be carried out in a manner that does not cause flooding or water penetration to any adjacent building or structure.

4.8 Site Contamination

Contaminated sites require special management during excavation. Personnel may be exposed to contamination in the soil through inhalation, ingestion (swallowing) and through skin absorption. These substances may include heavy metals, hydrocarbons, insecticides, asbestos, silica dust, combustible material, or biologically harmful material from buried wastes.

If it is determined that these substances may be present or if they are encountered during the excavation process:

a system to eliminate or control these hazards must be investigated and implemented; and

a strategy must be developed for the storage and eventual treatment or disposal of these materials.

The Area Superintendent must ensure that any material imported as fill or exported as waste material has been evaluated for contamination.

Note: In some circumstances, exporting contaminated material from a site requires Local/State Government approvals and these must be obtained before the material is allowed to leave the site.

4.8.1 Acid Sulphate Soils

Acid sulphate soils are common in low-lying coastal areas and represent a significant environmental threat when unearthed. The Area Superintendent must ensure geo-technical assessment of the site investigates the potential of encountering acid sulphate soils during excavation operations.

Where acid sulphate soil is identified as a risk:

all personnel involved in excavations must receive training in how to recognise acid sulphate soils and how to manage the risks; and

the risk must be managed and treated through the application of lime or by ensuring that the affected area is submerged to control oxidation.

5.0 PLANT & EQUIPMENT

5.1 Selection and Transport of Excavation Plant and Equipment

5.1.1 Selection

Plant and equipment used for excavation must be:

suitable for the work to be done;

suitable for the location of the work site; and

inspected by a Competent Person prior to use.

5.1.2 Transport

All excavation plant and equipment must be:

transported to the work site on an appropriate trailer, truck or carrier; and

inspected before it enters the worksite to ensure it is free of soil and weeds.

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5.1.3 Specifications

As a minimum:

ride-on tracked, wheeled or rubber-tyre vehicles entering an excavation must be fitted with a certified FOPS cab or canopy and ROPS;

tracked, wheeled and rubber-tyre heavy equipment working around an excavation should be fitted with a ROPS cab or canopy;

all excavators working on the site must have ROPS/FOPS cabs or canopies; and

all electrical and fuel-powered equipment introduced into an excavation must be in good mechanical and electrical order.

5.2 PPE

All personnel operating excavating equipment and working in the vicinity of excavation work must wear appropriate PPE. In addition to QGC minimum field PPE requirements, other PPE may be required if personnel are:

exposed to hazardous substances or contaminated soils;

entering confined or restricted areas; or

conducting activities within the excavation that require additional precautions (e.g. double eye/face protection for grinding works).

6.0 TRAINING & COMPETENCE

6.1 Training Requirements

Personnel performing excavation work must be qualified, trained and competent for the task and the level of risk involved. Specific competencies required for the work (e.g. confined space training) must be identified during the work planning process.

As a minimum, all personnel involved in excavation activities:

must have a current general construction induction card; and

must have been trained and assessed as competent at a level appropriate to their role and level of responsibility.

In addition, all operators of plant used for excavation must have been verified as competent.

6.2 Engineering Resource

The business must provide an engineering resource who is available to provide guidance on identifying and mitigating excavation risks. As a minimum:

this person must have at least three years’ experience in stabilising trenches; and

this person must be a geo-technical engineer or hold a qualification that covers:

o relevant standards, legislation and codes of practice;

o risk identification, assessment and controls specific to trenching collapse;

o safe work practices for installing controls;

o planning and preparing for trenching work;

o identifying underground services; and

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o identifying soil types and other factors that affect the stability of a trench.

7.0 SAFE WORK PRACTICES

7.1 Supervision

A competent QGC representative must be present for the identification, exposure and excavation of:

any live gas or electricity services, regardless of voltage or pressure;

any other service within 3 metres of a live gas or electrical service;

any other services identified as high risk; and

The QGC representative must be present whenever excavation activities get within 3m of the above services. This person must have experience and skills commensurate with the level of risk involved in the task.

A contractor supervisor must be present for:

the identification, exposure and excavation of all known services, regardless of identified risk; and

any mechanical excavation within 15m of a live service.

The permit holder for the excavation activity must be on site at all times during excavation activities.

7.2 JSEA/Step Back

Immediately before an excavation task begins, the work group must use the JSEA and/or Step Back process to:

identify any new/ unique hazards specific to the work area; and

ensure all persons involved with the activity are aware of the work hazards and the controls required.

7.3 Installed/Live Services

7.3.1 Gas Detection

Where relevant, appropriate controls must be implemented to prevent accidental ignition of flammable vapour or gas. If the risk is identified, the work area must be monitored using approved and correctly calibrated gas detectors before and during the work activity. Refer to AS 2885.3:2001 Pipelines - Gas and liquid petroleum - Operation and maintenance.

7.3.2 In-Field Identification of Live Services

All installed underground services must be located and identified in-field before excavation begins. Once the position of the service has been confirmed using instrument cable/pipe locators and mechanical probes, the service must be visually identified through potholing. When potholing:

hand digging or vacuum excavation must be used;

picks and crowbars must not be used;

a contractor supervisor must be present; and

a QGC representative must confirm the identification and location of the service before any further excavation activity begins.

If the identified service is not going to be fully exposed at the time of identification, it must be identified with colour-coded conduit (see Section 7.4.1).

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Note: Positive identification of services must occur within a minimum of 3 metres (dependant on workplace risk assessment) of the planned excavation; this includes the area used to bench or batter.

7.3.3 Exposure of Live Services

In all cases, known services must be vacuum or hand excavated (without picks or crowbars) until fully exposed. The excavation must be witnessed by the contractor supervisor. (Also refer to Section 7.1 for QGC supervision requirements).

When pipes are to be laid across existing services by horizontal directional drilling, the safe passage must be verified by opening an excavation above the crossing point. Separation distances between existing and new assets must be agreed by the asset owner prior to installation.

If any damage is caused to an underground service, no matter how minor, it must be reported as soon as possible. Work must only continue once the damage has been repaired, or it has been assessed and confirmed by a Competent Person that it is safe to do so.

7.3.4 Water Excavation Equipment

Water excavation equipment capable of more than 3200psi requires a level 2 risk assessment and relevant Site Safety Manager approval before a PTW can be issued.

7.3.5 Mechanical Excavation Near Live Services

Mechanical excavation (including auguring and boring) is not permitted:

directly above live services, irrespective of the depth; and

within 1m diagonally and 1m below any known live service.

All mechanical excavation in close proximity (defined as one bucket width) to the 1m exclusion zone must be undertaken with a blunt scraper. Tiger teeth are not permitted.

If it is not possible to comply with the criteria above due to the presence of rock:

the current permit to work must be immediately cancelled

a formal risk assessment must be performed; and

a new permit to work must be approved by the relevant Site Safety Manager and issued.

A spotter must always be present during the excavation.

7.3.6 Excavation Near Underground or Overhead Electrical Hazards

Specific work controls must be developed for work near under underground or overhead power lines. These must include:

the option of isolating the electrical service;

the use of a competent spotter;

the use of warning signs and notices; and

the application of exclusion zones.

Written safety advice must be obtained from the Asset Owner. Refer to QGC Safe Access to Low Voltage Electrical Apparatus Procedure (QCOPS-BX00-HSS-PCE-000011) and QGC Safe Access to High Voltage Apparatus Procedure (QCLNG-BX00-HSS-PCE-000105) and Electrical Safety Act 2002.

7.3.7 Service Identification Markers

Underground services and identification markers, such as flags or survey pegs, must be consistently colour coded. Details of the colour coding must be included as part of the Excavation Certificate.

Identification survey pegs must be uniquely labelled or numbered and must include information referencing service type, pipe/conduit configuration and known service depth.

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Note: Older services may not be colour coded in accordance with modern systems or may be housed in a duct or other covering that is incorrectly coloured for that particular service (e.g. an electrical cable that is wrongly sheathed within a white telecommunication duct). Dirty service equipment and/or poor light conditions (e.g. during emergency work at night) may make services appear a different colour to what they actually are).

7.3.7.1 Colour Codes for Service Identification

As a guide, the following marking colours are often used for marking services (as per AS/NZS 4130 – APIA Code of Practice Upstream Gathering Networks – CSG Industry). These colours are to be used within QGC.

Application Colour

(AS/NZS 4130 – APIA Code of Practice Upstream Gathering Networks – CSG Industry)

Drinking Water (Potable Water) Blue

White

Recycled Water Purple

Pressure Sewer Cream

Gravity Sewer (utility) & Sanitary Drainage (private)

Grey

Storm Water N/A

Electrical Orange

Gas Yellow

Communications White

7.3.8 Temporary Services

Where electrical cables or other services are laid in trenches for temporary service supply, they must be protected (with conduits, slabs, etc.) and marked in accordance with the relevant legislative and Australian Standards requirements.

7.3.9 Placing Electrical Cables

Electrical cables must be covered by at least 600mm of fill. If the cover is less than 900mm a strip of bright orange polyvinyl chloride or polyethylene must be placed above the cable. The strip must have continuous markings on the upper surface indicating that an electrical cable is below. Refer to Electrical Safety Code of Practice 2010

7.4 Access and Egress

Safe and sufficient means of access and egress must be provided at all times whenever and wherever personnel are working in an excavation:

a minimum of two access/egress points must be in place for every 9m of excavation;

ladders may be used but they must extend at least 1m above the top of the excavation; and

where possible, ladders must be placed at or near junctions or corners of an excavation.

If an excavation is more than 1.2m deep, the following control measures must be applied:

The Permit Holder must ensure there is ladder access installed at least every 9 metres of length;

For excavations shorter than 9 metres, an emergency means of access must be provided. This can take the form of:

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o a second ladder placed near the excavation that can be installed quickly ;or

o ingress /egress ramps at either end of the excavation;

Personnel must not work alone. The Permit Holder must enforce this; and

Entry points must be secured when work is suspended and the excavation is left unmanned. This protection must include, where appropriate, the use of lighting and reflective signage (see Section 4.6).

7.5 Ground Support

7.5.1 Depth Less Than 1.2 metres

Excavations of less than 1.2m depth do not need to be shored, benched or battered unless they pose an unacceptable risk to workers or the public. When determining this risk, the following factors must be considered:

soil type and condition (e.g. acid sulphate soils);

accessibility to the public;

protection and barricading required;

expected duration of exposure;

the proximity of heavy equipment to persons in or around the trench;

the position of the water table in relation to the bottom of the excavation; and

the requirement for de-watering, and whether it will affect the stability of the trench.

Where the site assessment indicates an unacceptable risk of injury through excavation collapse, or where there is a possibility of the sides of an excavation becoming unstable (e.g. because of ground conditions and/or superimposed loading), the excavation must be supported irrespective of depth.

7.5.2 Depth 1.2 Metres or Greater

Excavations deeper than 1.2m must be controlled to prevent the risk of collapse. This may include being supported on all sides by shoring, benching, battering, or any combination of these.

Workers in excavations deeper than 1.2m must never work outside the protection of ground support systems, no matter the circumstances.

As part of the planning process for an excavation deeper than 1.2m, a Competent Person must examine the ground conditions and submit a statement in writing detailing the findings of the examination. This statement must include:

the type(s) of ground encountered;

the calculations used in deciding the method of protection required, if relevant; and

any other specific issues that need to be addressed.

This statement must be signed by the Competent Person and kept on with the PTW.

7.5.3 Design

All ground supports must be designed by a Competent Person for the specific work activity and installed by a competent, trained person. The design must consider:

soil classification;

depth of excavation;

water content of the soil;

weather impacts on site conditions; and

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adjacent operations.

The Area Superintendent must ensure all methods of ground support are designed in accordance with acceptable engineering principles, published technical standards and legislative requirements.

7.5.4 Shoring

Shoring or ground support (in the form of rock bolts, shotcrete etc.) must:

be installed as per the engineered design requirements;

be installed without delay as the excavation progresses;

extend at least 300mm above the edge of the excavation, or a fender board of the same height must be provided.

Workers installing the system must be given clear installation instructions, including drawings. If the installation differs from the design, all changes must be referred back to a Competent Person for approval.

Shoring must be inspected:

daily, before any work commences;

after any fall of the sides or working face; or

after blasting.

Shoring must be dismantled in the reverse order to its installation.

7.5.5 Benching and Battering

Benching and battering may be used to support excavations:

where space and conditions permit; and

where the decision has been approved by a Competent Person.

A Competent Person or a geo-technical engineer must give written approval if the overall slope of the benched or battered wall exceeds 45 degrees to the horizontal (i.e. the benches are higher than their width).

7.5.6 Narrow Trenches, Ditches and Small Holes

Shoring, benching and battering is generally not required if it is impossible for a person to fully enter the trench, ditch or round penetration, irrespective of the depth of the excavation. However, these narrow excavations still constitute a hazard for other reasons, and therefore due consideration must be given to implementing effective controls for those hazards (e.g. covering, barricading etc.).

7.6 Fall Prevention and Falling Objects

The task risk assessment (SWMS) must determine the controls required to protect personnel in excavations from falls and falling objects.

7.6.1 Fall Prevention

As a minimum, the following fall-prevention controls must be considered:

clearly defined and protected pedestrian detours;

intermediate platforms for deep excavations;

safe means of movement between different levels of the excavation;

an adequate fall arrest system; and

backfilling as work progresses.

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All controls must be properly installed and maintained until the work is completed or until there is no longer any risk of personnel falling into the excavation.

Where the risk of falling/work at heights has been identified by risk assessment, all required fall prevention/work at height controls must be in place.

7.6.2 Falling Objects

Where falling object hazards have been identified:

overhead protective structures must be provided; and

toe boards must be installed in deep excavations.

Loads must not be lifted, suspended or moved over a person under any circumstances.

Note: The risk of material falling into an excavation increases during high winds.

7.6.3 Barricades and Handrails

Where a person could fall 1.0m or more into an excavation, barricades or handrails must be installed as soon as practicable after excavation.

If barricades or handrails are removed to allow access for plant or materials, they must be re-installed as soon as the access is no longer required.

7.6.4 Walkways

Walkways across trenches must meet the requirements of AS1657 Fixed platforms, walkways, stairways and ladders — Design, construction and installation: guard rails must be at a height above the walkway of not less than 900mm or more than 1100mm;

another rail is required with a gap of no more than 450mm between it and the top of the toe board or the top rail unless the there is a sheet of sturdy mesh, sheeting or other material between the top rail and the toe board;

toe boards must extend at least 100mm above the surface of the walkway and the gap between the toe board and the walkway must not exceed 10mm; and

the minimum width for walkways with guard rails on both sides is 550mm; otherwise the minimum width is 600 mm. The recommended width for two way traffic is 900mm.

Note: refer also to QGC Fall Prevention Procedure (QCOPS-BX00-HSS-PCE-000004).

7.7 Excavated Material

Care must be taken to prevent the weight of excavated material (spoil) contributing to excess loading and collapse of the excavation edge.

To prevent debris falling into the excavation:

at least 600mm of space must be left between the excavation and spoil in unoccupied excavations; and

at least 1.0m of space must be left between the excavation and spoil in excavations occupied by personnel.

In all cases, excavated materials must be placed to present no risk to personnel, pedestrians, road traffic or other work activities.

Where the spoil is to be re-used:

the surface materials must be kept separate from the subsoil to allow soil layers to be replaced in the correct order; and

the spoil should be protected against adverse wet weather conditions; and

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the spoil should be covered to maintain moisture content.

For excavations in trafficked roads, excavated soil should be placed to form an additional barrier against traffic, if possible.

7.8 Inspections

The Area Superintendent must ensure that a documented system of regular inspections is in place for trenches and excavations. A Competent Person must conduct an inspection:

before the start of each shift;

after any ground slip or collapse of a section of wall;

after any substantial rain event which may have led to water ingress;

after any change in ground conditions (e.g. dry weather);

after every blast;

after any hazardous substances or material is encountered; and

after any change in site conditions (e.g. other construction activities taking place in the vicinity).

As a minimum, the inspection must cover:

potential instability in the work area, including excessive edge loading;

the adequacy of the working space, and access and egress for personnel in the excavation;

the adequacy of supports and barriers; and

risks posed to adjacent work workers.

Any issues identified during the inspection must be corrected as soon as practicable, and before any other work takes place in the excavation.

Copies of the inspection results must be held with the PTW documentation at a prominent location in the work area.

Note: Any person in the work area may stop the excavation works if the works appear to be unsafe.

8.0 ENVIRONMENTAL AND COMMUNITY ISSUES

8.1 Water Management

Controls must be in place to manage water entering the excavation and draining from the works. Sources of water ingress include seepage, flooding from other existing watercourses, flooding from storm events and flooding from burst water mains and sewers in the excavation. Tidal or stream effects may also impact excavations in coastal or fluvial environments.

Disposal of water must be given careful consideration. Water that has occupied a trench or excavation for even a short period may not be suitable for direct discharge to local waters or the storm water system.

The Area Superintendent must ensure the quality of water requiring disposal has been assessed and that disposal meets local/State government regulations.

8.2 Waterlogged Ground

Where waterlogged ground conditions are expected and water-removing equipment is required, it is usually satisfactory to pump from sumps within the excavation. Where in-trench pumps are used for prolonged periods, particularly in ground of a sandy or silty nature, it may be necessary to install suitable filters behind sump linings to prevent loss of ground which could affect stability. Similar filters may be

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necessary along the trench sides in extreme conditions. Trench sumps must not be excavated to such a depth that they present a hazard.

Alternative water removing methods must be considered in any of the following circumstances:

where it is proposed to excavate through running sand or water bearing peat;

where pumping from trench sumps is inadequate to keep trenches free from water;

where deep excavations have to be made in waterlogged ground; and

where excavations are to be present for a considerable period of time in waterlogged ground.

Alternative measures include sumps external to the excavation, well points, electro-osmosis and consolidation by freezing or by chemical process. Where it is anticipated that such measures will be needed, the advice of a suitability qualified engineer experienced in such works must be sought.

8.3 Erosion from Adverse Weather

To prevent erosion from adverse weather, excavations must be planned to:

minimise the erosive effects of concentrated flow;

reduce total soil disturbance;

reduce total slope length and gradient;

provide stabilising ground cover protection from the effects of raindrop impact.

8.4 Cultural, Environmental and Archaeological Issues

Trenching and excavation operations may unearth or damage the cultural or ecological value of a site (e.g. remnant vegetation or aboriginal artefacts). Before beginning work in an area where this may be an issue, the Area Superintendent must ensure that the cultural, ecological and archaeological value of the site has been assessed and appropriate measures are in place to maintain the values identified.

9.0 COMPLETION OF EXCAVATION WORKS

9.1 Filling Around Services

Where services are installed in trenches, care must be taken not to damage the service or any coating or wrapping during backfilling works. To protect pipe coatings and polyethylene pipe, subsoil fill must be clean, moist and free from sharp stones greater than 18 mm in size. Backfill soil may be sieved to meet this requirement or soil may be imported as required.

Fine fill material should be packed firmly around pipes or fittings to give a minimum compacted thickness of 75mm. Cementitious materials must not be used as fine fill material around pipes.

When placing fine fill around large diameter pipes, or where the side gap between the wall of the excavation and the pipe is greater than 75mm, special care must be taken to ensure firm compaction of the fine fill especially around the lower half of the pipe.

The required thickness of other levels of reinstatement will depend on the location of the excavation (e.g. private land, carriageway, footway, etc.) and the requirements of the landowner or management authority. All unbound materials used in these levels must be placed in layers no deeper than 300mm within the trench and firmly compacted using approved mechanical compaction equipment.

Excavated material may be suitable for re-use as backfill material provided that the material is moist, does not contain any particles larger than 75 mm and is uniformly graded, but not single sized.

Use of cement or stabilised sand over buried assets must be approved by the asset owner.

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9.2 Completion of Works

At the completion of the work, the work site must be cleared of all rocks, soil and other debris and returned, as far as is practicable, to its original condition or finished to an agreed plan. Any re-vegetation of the work area must be conducted with suitable species and in consultation with relevant local government personnel.

Drawings and other documentation must be updated to reflect any changes due to the work just completed.

10.0 AUDIT AND MANAGEMENT REVIEW

QGC HSSE must conduct periodic audits and reviews of:

operational procedures, work control arrangements and other requirements applicable to excavation activities; and

workplace application of this procedure.

All audits must comply with Governance & Assurance Standard (QCGGC-BX00-HSS-STD-000005).

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APPENDIX A – DOCUMENT DISTRIBUTION RECORD (RACIE SHEET)

DOCUMENT DISTRIBUTION SHEET

Consulted:

Enter name/position of those required to review the document (excl. Key Consulted persons – see forward)

Informed:

Enter name/position of those to receive the completed document

Responsible Person: Lynn O’Malley Principal Technical Advisor HSSE Upstream Operations

Accountable Person: Richard Schokman General Manager Upstream Operations

Endorser: Peter Thompson Vice President Production Operations

QGC Operations and Projects Personnel

QGC HSSE [email protected]

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RACIE Terms

R Responsible: the person who actually produces the document

A Accountable: the person who has to answer for the success or failure of the quality and timeliness of the document

C Consulted: those who must be consulted before the document is published

I Informed: those who must be informed after the document is published

E Endorsed: the person who must approve the document before publication

Revision Record

Issue Date Reason for Issue Responsible Accountable

A 4.04.12 Issued for comment L O’Malley Rod McPherson

0 29.05.12 Issued as Final L O’Malley Rod McPherson

1 11.12.13 Revised to align with QGC Excavation and Trenching Standard – Issued for review

L O’Malley Richard Schokman

2 5.02.14 Issued for use L O’Malley Richard Schokman

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APPENDIX B – DEFINITIONS AND REFERENCES

Definitions

In this document, the following definitions apply:

Term Meaning

Angle of repose The slope at which dumped or excavated material is naturally stable and does not fall away

Backfill Material used for refilling excavations

Barricade An object such as jersey kerb or plant capable of providing effective protection against traffic entering the work site. IMPORTANT: Barricade/Barriers <4.2m clear of traffic at 60kmph, <3.0m clear of traffic at <60kmph and <6.8m clear of traffic at 80kmph require design verification and signoff by the traffic engineer (check with local/state requirements)

Barrier A self-supporting structure or a self-supporting series of continuous solid barriers erected or placed to restrict the entry to a workplace

Batter or slope The angle of an excavation in relation to the horizontal

Battering The development of a sloped wall to an excavation to a predetermined angle.

Benching The development of stepped sides to an excavation to lessen the overall slope of the excavated walls to a predetermined angle

CAD Coordinator Person (engineer, senior surveyor etc.) with the capability to access and use the current services model or equivalent process/system. This person can be assigned the responsibility to provide services information as identified in survey documentation, services drawings, as built construction drawings and provide overlay drawings such as service locations onto design drawings

Closed Sheeting A continuous frame with vertical or horizontal sheathing planks placed side by side to form a continuous retaining wall supported by other members of a support system used to secure the face of an excavation

Competent Person A person who has acquired through training, qualification or experience the knowledge and skills to carry out the task test or inspect equipment. Generally 'competency' is assessed by QGC or a third party. Note: In relation to performing an inspection or other task for a control measure, means a person who has acquired, through training, qualifications or experience the knowledge and skills to do the task in a safe way, including knowledge of relevant Australian Standards, Industry Standards, Codes of Practice and other legislation.

Confined Space Entry All situations where a person is entering or partially entering a space that:

is not designed or intended primarily to be occupied by a person;

is designed or intended to be at normal atmospheric pressure while the person is in the space;

is likely to be a risk to health and safety from:

o an atmosphere that does not have a safe oxygen level

o contaminants, including airborne gases, vapours and dusts, that may cause injury from fire or explosion

o harmful concentrations of any airborne contaminants

o engulfment

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Term Meaning

Construction Zone A defined location that has been formally identified with clearly defined boundaries in which the following activities may occur:

a Greenfield or Brownfield site with special cordoned off barriers and denoted safe for the purpose of the work to be done;

excavation, including the excavation or filling of trenches, ditches, shafts, wells, tunnels and pier holes, and the use of caissons and cofferdams;

building, including the construction (including the manufacturing of prefabricated elements of a building at the place of work concerned), alteration, renovation, repair, maintenance and demolition of all types of buildings; and

civil engineering, including the construction, structural alteration, repair, maintenance and demolition of, for example, gas wells, pipelines, ponds, compression plant, power stations, roads, bridges and tunnels, and works related to the provision of services such as communications, drainage, sewerage, water and energy supplies, etc.

Cover A steel plate or other suitable material capable of withstanding the loads that may be imposed upon it and of sufficient weight or secured to prevent unauthorised removal.

Dial before you dig (DBYD)

A free referral service for information on underground pipes and cables anywhere is Australia.

Disconnected service Applies to all services power/communications/gas/sewer-water/storm water, etc.)

A disconnected service is one which is rendered permanently out of service

These services are decommissioned, disconnected /cut off from the supply source with the intention that they are redundant – they are no longer part of the service owners’ operational network.

Earthmoving machinery

Operator controlled mobile plant used to excavate, load, transport, compact or spread earth, overburden, rubble, spoil, aggregate or similar material, but does not include a tractor or industrial lift truck

Excavation A hole in the earth, or a face of earth, formed after rock, sand, soil or other material is removed.

Exclusion Zone An area from which all persons are excluded during excavation work

Face An exposed sloping or vertical surface resulting from the excavation of material

Fence Continuous enclosure not less than 1800mm in height that prevents unauthorised access to the work area and of such strength to remain erect in position during all conditions

FOPS Acronym for ‘falling object protection system’ – A protective structure over an operating cabin of a vehicle designed to prevent object falling from above from entering the operator’s station-Often integrated with a ROPS cabin but may be installed as a stand-alone system

Geo-technical engineer

An engineer, whose qualifications are acceptable for membership in the Institution of Engineers Australia and who has qualifications and experience in soil stability, soil mechanics and excavations

Greenfield Zone A formally designated Zone that has been clearly identified, fully risk assessed, and has been demonstrated to have limited operating infrastructure, live services or above or below ground, prior to new work being undertaken.

Handrail A rail one meter in height (plus or minus 100mm) effectively supported, security and of such rigidity and strength capable of providing support so as to prevent persons falling

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Term Meaning

Isolated Service Applies to all services power/ communications/ gas/ sewer-water/ storm water etc.

An isolated service is one, which is rendered temporarily out of service. I.e. electrical services power outage/water supply cut off – stop valves closed/ sewer mains plugged etc.

Services are isolated for one of two purposes:

o To enable work to be carried out in close proximity to the service in safety or to minimise risk of electrocution/explosion/fire/fluid leakage if the service is inadvertently damaged during work activities; or

o To enable work on the service (cut tee into water main, install sewer junction, CCTV camera inspection, connect power to switch gear etc.) to be undertaken safely and in such a manner that temporary disruption of supply to consumers/public is controlled

Job Safety and Environment Analysis (JSEA)

A component of QGC’s overall risk management process that occurs at the area of work immediately prior to commencement of the task under a PTW

A JSEA involves conducting a work party review of all relevant HSSE documentation associated with the task and capturing any additional hazards not already identified (e.g. in the, PTW, SOP or SWMS), assessing the risk/s and deciding on appropriate controls to reduce the risks

Level 2 Risk Assessment

A risk assessment facilitated by a competent person independent of the work.

Limits of approach A table, modified to suit local requirements which specifies the minimum distance between the service and mechanical or hand excavation

Non destructive digging

A process of digging holes with the use of air and water whilst the debris is vacuumed and saved for back fill

Operator protective device

A roll-over protective structure (ROPS), falling object protective structure (FOPS), operator restraining device and seatbelt

Overburden Surface soil that must be displaced

Permit Holder A person deemed competent and approved by QGC to carry out the work specified on a PTW and to whom a PTW can be issued by the Permit Issuer

Permit Issuer A person deemed competent and approved by QGC to define the control measures to be implemented in establishing a safe work environment for the Work Party and issue PTW and supporting documents

Positive identification Measures have been undertaken to determine that the service located is actually the service it is believed to be:

Measures include pot holing - soft dig options including non destructive excavation methods and scanning /detection techniques

Potholing The use of a high pressure water and vacuum system to safely locate buried pipelines and cables

Powered mobile plant Plant that us provided with some form of self propulsion that is ordinarily under the direct control of an operator

Prescribed information

Information about an underground service, necessary to safely undertake excavation/trenching work at or near the service, including:

(a) The location of the service (b) The type of the service (c) The depth of the service (d) For an electrical service—whether the service is live; and (e) The restrictions to be followed in doing the work

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Term Meaning

Runners Any timbers, metal or sheet piling used to form the vertical members if an excavation support

Safe Slope The steepest slope at which an excavated face is stable against slips and slides, having regard to the qualities of the material in the face, the height of the face, the load above the face and the moisture conditions

Safe Work Method Statement (SWMS)

A work statement produced as part of the submission for a Permit to Work that:

identifies the work activity to be undertaken and the proposed steps in the job;

states the safety hazards and or associated risks for each step;

describes the control measures that will be applied to the work activity and the revised risk;

and includes a description of the equipment used in the work and the competencies of the workers.

Scafftag Propriety trade mark commonly used to refer to a system of tagging scaffolds or other equipment to visibly record inspections and status

Service authority The owner, controller or operator of an underground or overhead service-

For the purpose of this guideline an underground or overhead service includes electrical, water, sewage and drainage, gas, telecommunications, petrochemicals and hazardous substances

Must A mandatory term – no deviation is permitted without written approval from the Group Technical Authority.

Shoring The use of timber, steel or other structural material to provide effective and adequate temporary support to maintain the stability of the walls of the excavation

Soft dig Is a non-mechanical means to expose / identify the location of underground services by using wooden handled or other insulated implements, i.e. shovels, mattocks etc.-Non destructive excavation includes methods such as Vacuum techniques

Soldier Vertical upright timber or steel element used for supporting a trench wall

Strut or screw jack A timber or steel member usually horizontal in compression, resisting thrust or pressure from the face or faces of an excavation. Screw jack struts are adjustable

Support Structure A shoring system to maintain the stability of the walls and roof of an excavation and includes a trench shield

Tom Structural member used to hold soldiers against a trench wall or to press walers apart in a close sheeted trench

Trench An excavation where the maximum depth is greater than the width-

Generally developed temporarily for the placement or repair of pipes and services

Trench Shield A structure with two vertical side plates permanently braced apart by cross frames or struts designed to resist the pressure from the walls of a trench and capable of being moved as a unit

Vacuum truck A truck mounted, heavy duty industrial vacuum loader designed to pneumatically convey solids, liquids, sludge or slurry through suction lines typically 5-10 cm in diameter

Waling A horizontal beam supporting vertical timbers, runners or sheeting

Water scouring An erosion process resulting from the action of the flow of water

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Term Meaning

Zone of influence The volume of soil around an excavation, measured from the bottom level of the excavation, between the sides of the excavation and a line drawn at an angle from the horizontal. Generally, the zone of influence extends some 30 degrees from the horizontal for sands and 45 degrees for other material

Acronyms and Abbreviations

In this document, the following acronyms and abbreviations apply:

Acronym/Abbreviation Meaning

DBYD Dial Before You Dig

FOPS Falling object protection system

JSEA Job Safety and Environment Analysis

PTW Permit To Work

ROPS Roll over protective structure

SWMS Safe Work Method Statement

Referenced / Associated Documents

Ref. Document Number Title/Description

1. BGA-OPS-OS-0032 Excavation and Trenching

2. QCQGC-BX00-HSS-STD-000021 Excavation and Trenching Standard

3. QCGGC-BX00-HSS-STD-000030 Working in Confined Spaces

4. QCOPS-BX00-HSS-PCE-000002 Permit to Work Procedure

5. QCOPS-BX00-HSS-PCE-000005 Safe Work Method Statement Procedure

6. QCOPS-BX00-HSS-PCE-000003 Confined Space Entry Procedure

7. QCOPS-BX00-HSS-PCE-000004 Fall Prevention Procedure

8. QCOPS-BX00-HSS-PCE-000011 Safe Access to Low Voltage Electrical Apparatus Procedure

9. QCLNG-BX00-HSS-PCE-000105 Safe Access to High Voltage Apparatus Procedure

10. – QCLNG-BX00-CON-PCE-000012 Managing Crossings of QGC Infrastructure by Third Parties and QGC Contractors

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Ref. Document Number Title/Description

11. – QCOPS-OPS-HSS-GDL-000001 Guidelines for work near QGC Pipelines

12. QCOPS-BX00-HSS-CER-000001 Confined Space Certificate

13. QCOPS-BX00-HSS-CER-000003 Excavation Certificate

14. QCOPS-BX00-HSS-FRM-000002 SWMS form

15. QCOPS-BX00-HSS-FRM-000010 Confined Space Identification Risk Assessment form

16. QCOPS-BX00-HSS-PLN-000001 Task Rescue Plan

17. Queensland Workplace Health and Safety Act 2011

18. Queensland Workplace Health and Safety Regulation 2011

19. Model Code of Practice - Excavation Work

20. Electrical Safety Act 2002 and Electrical Safety Reg

2002

21. Queensland Manual of uniform traffic control devices Part 3: Works on roads

22. Code of Practice: Working near exposed live parts

23. AS 1345:1995 Identification of the contents of pipes, conduits and ducts

24. AS1657 Fixed platforms, walkways, stairways and ladders — Design, construction and installation

25. AS 2885.3: 2001 Pipelines: Gas & Liquefied Petroleum Maintenance and Operation

26. AS/NZS 3012: 2010 Electrical installations – Construction and demolition sites (Section 2.7 Lighting and luminaries)

27. AS 2293.1: 2005

Emergency escape lighting and exit signs for buildings Part1: System design, installation and operation (Section 5 Design of emergency escape luminaire installation)

.

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APPENDIX C – CHANGE HISTORY

QCOPS-BX00-HSS-PCE-000007_1 This procedure has undergone a major review to align to the structure of, and controls stipulated, in the QGC Excavation and Trenching Standard QCQGC-BX00-HSS-STD-000021. To provide greater clarity within the procedure, several sections have been retitled and reworded without changing their original intent. Where double up of information occurred in the previous revision, this has been deleted. Key changes and additional controls within this revision are outlined below

Section Change History Details 2.0 Responsibilities – amended to align with PTW Rev 3. Duplication of responsibilities in PTW

procedure deleted.

3.2 – A PTW is required for all excavations, unless:

the excavation has been appropriately risk assessed and has been approved by the Area Owner as a one-off, low-risk activity; or

the task is listed on the site’s Approved Task List (ATL). If excavation will occur within the 15 metre pipeline exclusion zone, the relevant QGC Area Superintendent or delegate must be consulted and Guidelines for work near QGC Pipelines (QCOPS-OPS-HSS-GDL-000001) must accompany the PTW application.

3.3.1 Site Survey of Area to be Excavated Additional criteria added to meet the QGC standard.

3.3.2 – QGC Crossing Process

New subsection included to cover the recently introduced crossings process.

4.1 – Adjacent work activities

New subsection included to meet QGC standard.

6.0 – Training and Competence

New subsections 6.1 Training Requirements & 6.1 Engineering Resource included to align with the QGC standard

7.1 – Supervision

This subsection has been expanded to include the additional supervision criteria detailed in the standard and expanded to provide greater clarity on requirements.

7.3 – Installed Live Services

This subsection has been divided into 9 additional sections. 7.3.1 Gas Detection 7.3.2 In field Identification of Live Services 7.3.3 Exposure of Live Services The additional criteria set out in the standard have been included. 7.3.4 Water Excavation Equipment – new subsection “Water excavation equipment capable of more than 2000psi requires a level 2 risk assessment and relevant Site Safety Manager approval before a PTW can be issued.” 7.3.5 Mechanical Excavation Near Live Services The additional constraints and limits set out in the standard have been included. 7.3.6 Excavation Near Underground or Overhead Electrical Hazards. Reworded for clarity - criteria unchanged 7.3.7 Service Identification Markers and 7.3.7.1 Colour Codes for Service Identification These subsections have been amended to align with AS/NZS 4130 – APIA Code of Practice Upstream Gathering Networks – CSG Industry). These colours are to be used within QGC. 7.3.8 Temporary Services – No change to content.

Appendix C

Excavation Certificate has been deleted to enable independent revisions to occur. This certificate is readily accessible via the intranet.

Appendix C now details the procedure change history

Note: wording improvements and deletion of duplicated information have not been identified in the change history. A copy of the procedure with all changes tracked is available for review upon request.

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QCQGC-BX00-HSS-PCE-000007_2

– Section – Change History Details

– 3.1.1 Added bullet: “oxygen depleting soils”

– 3.1.2 – Last paragraph –added “…for approval by the Local Road Authority if required.”

– 3.2 – Amended conditions requiring PTW to:

– A PTW is required for all excavations deeper than 300mm in brownfield areas.

– A PTW is required for excavations less than 300mm in depth unless: …

– 3.3.1 – Added “Particular attention should be given to investigation of secondary infrastructure that may have been buried with large assets such as fibre optic cables, anode cables, etc.”

– 3.3.2 – Reworded 2nd

Paragraph …A crossings application is not required; contact the Crossings Team via email to request the crossings reference number.

– 3.4 – Added bullet: “map/aerial picture of area identifying valve locations”

– 3.5 – Added bullet: “how the required compaction levels will be obtained”

– 4.3 Added bullet to Barrier must be: “installed outside of the zone of influence i.e. horizontal clearance equal to trench depth.

– 4.3 –par 5 – Added “When an excavation is opened exposing a buried asset, protection measures must be put in place to protect the asset from vehicle impact if identified as a risk during the Risk Assessment or deemed as required by the relevant Superintendent.

– 4.4.1 – Deleted AS 1742.3 2009 and replaced with the Queensland Manual of uniform traffic control devices Part 3: Works on roads

– 4.5 – par 2 Added “If it is required to cross buried infrastructure with vehicles, approvals must be obtained from the relevant area and asset department if required. Refer to Guidelines for work Near QGC Pipelines QCOPS-OPS-HSS-GDL-000001.”

– 4.7 – par 1 – Reworded to “Excavation work which is likely to impact on the stability and security (including stress cracks) on any part of a structure must not commence until adequate protection measures are employed to monitor and maintain the existing structural integrity of the asset.”

– 7.3.3 – par 2 – Inserted: “When pipes are to be laid across existing services by horizontal directional drilling, the safe passage must be verified by opening an excavation above the crossing point. Separation distances between existing and new assets must be agreed by the asset owner prior to installation.”

– 7.3.3 – par 3 Added “…no matter how minor…..assessed and…”

– 7.3.4 – Amended psi rating from 2000 to 3200

– 7.3.5 – Amended 2nd

bullet to: “within 1m diagonally and 1m below any known live service”

– 7.3.9 – New sub section: Electrical cables must be covered by at least 600mm of fill. If the cover is less than 900mm a strip of bright orange polyvinyl chloride or polyethylene must be placed above the cable. The strip must have continuous markings on the upper surface indicating that an electrical cable is below. Refer to Electrical Safety Code of Practice 2010.

– 7.6.1 – Where the risk of falling/work at heights has been identified by risk assessment, all required fall prevention/work at height controls must be in place.

– 7.7 – 1st bullet: to at least 600mm to align with QGC standard

– Par 2 added …“or other work activities.”

– 9.1 – – 2nd

last par – amended… “particles larger than 75 mm and is not uniformly graded (i.e. is not single-sized) to

… “particles larger than 75 mm and is uniformly graded, but not single sized

– Last par added “Use of cement or stabilised sand over buried assets must be approved by the asset owner.”

– Appendix B – Referenced /Associated Documents : Added:

– Working in confined spaces standard

– Queensland Manual of uniform traffic control devices Part 3: Works on roads

– Deleted :AS 1742.3: 2009

– Appendix B – Definitions:

– Amended Confined Space to Confined Space Entry and reworded to align with Working in Confined Spaces Standard.

– Amended Excavation to: A hole in the earth, or a face of earth, formed after rock, sand, soil or other material is removed.

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APPENDIX D – FEEDBACK FORM

FEEDBACK FORM

This form should be used to notify comment or suggestions for improvement, relating to any aspect of the document identified below. Please return the completed form by Email, to the Responsible identified in the associated RACIE matrix

Document title:

Excavation Procedure

Document No:

QCOPS-BX00-HSS-PCE-000007

Issue No:

Issue Date:

Comments by:

Name: ………………………………………………..

Position: …………………………………………..

Date: …………………………

Email address / Contact Tel.No: …………………………

Project / Business Unit: …………………………..

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