Underground Ground Control - · PDF file4.5 Shotcreting ... Underground Ground Control Uncontrolled copy. Use latest revision ... pillar and long hole extraction sequences, maximum

Major Hazard Standard

Underground Ground ControlUnderground Ground Control

** Uncontrolled copy. Use latest revision **Standard Coordinator: P. Teasdale EOF Coordinator: K. Thomas Group Manager -EHS - Martin WebbSAF-MHS-01 Rev. 2 Issued: 19/06/00 Page 1 of 22

© WMC Limited 1997The contents of this document are for the sole use of WMC employees and contractors and

may not be transmitted, in any form, to third parties.

PURPOSE AND SCOPE...........................2

DETAILS ....................................................2

1 Planning the Ground Control Strategy21.1 Producing the Ground Control Plan..21.2 Gathering Ore Body and Host Rock

Data.................................................21.3 Determining the Mining Method and

Equipment Options ..........................31.4 Designing the Excavation and Ground

Control System ................................31.5 Preparing the Multi-tiered Response

Plan .................................................51.6 Identifying the Required Resources..5

2 Resourcing Requirements for GroundControl ..................................................52.1 Equipment Selection .........................52.2 Documenting the Ground Control

Materials Specifications ...................52.3 Developing SWPs .............................62.4 Identifying the Required Competencies

........................................................7

3 Operations Management......................83.1 Operations Planning Requirements ..83.2 Ground Control Monitoring and

Evaluation Systems..........................8

4 Ground Control Tasks..........................9

4.1 Mandatory Requirements for WorkConducted in a Mine........................ 9

4.2 Re-entry Requirements .................. 104.3 Scaling............................................ 104.4 Inspecting Ground Reinforcement .. 114.5 Shotcreting ..................................... 124.6 Blast-hole Drilling............................ 124.7 Blasting........................................... 124.8 Bogging .......................................... 124.9 Rising ............................................. 124.10 Use of Checklists .......................... 134.11 Survey Mark-Up, Sampling Mark-Up

and Geotechnical Mapping............ 13

5 Monitoring the Ground Control Plan135.1 Monitoring Compliance with the

Ground Control Plan...................... 135.2 Monitoring the Effectiveness of

Ground Control Plan...................... 13

APPENDICES..........................................14A Definitions ............................................. 14B Related Documents............................... 16C Revision Information ............................. 16D Example of Ground Reinforcement

Installation Instructions ....................... 19E Example of a Ground Hazard

Identification and Control System....... 21


Underground Ground Control

** Uncontrolled copy. Use latest revision **

SAF-MHS-01 Rev. 2 Issued: 19/06/00 Page 2 of 22

PURPOSE AND SCOPEThe purpose of this Standard is to eliminate fatalitiesand serious injuries from rockfalls and to achieve‘best practice’ in ground control at all operations.This Standard applies to all WMC undergroundmines throughout the world, and covers:• Planning ground control• Resourcing requirements for ground control• Operations management• Ground control tasks• Monitoring• Auditing.

To achieve the purpose of the standard one of theprincipal requirements is:

No person is to go beyond supported groundi.e. ground supported or reinforced to anapproved standard for that rock type and madesafe.

All new accessible excavation areas in the mine shallbe supported to a minimum standard for that rock orexcavation type

Supported ground is ground that has been controlledto an approved standard and made safe through theappropriate use of controlled blasting, scaling,ground support and ground reinforcement(see Appendix A)

The Mine Manager shall ensure that the applicationof this Standard meets all regulatory requirements.

DETAILS

1 Planning the Ground ControlStrategy

The Ground Control Co-ordinator shall plan thestrategy for controlling the rock mass.

1.1 Producing the Ground Control PlanAt the end of the planning and design stage, aGround Control Plan shall be produced. The Planshall include the information specified in Sections 1.2to 1.6. In addition the Ground Control Plan shallspecify the following information or reference readilyavailable documents in which the information isprovided:• Background information for the Ground Control

Plan:– Ore body and host rock data

– Excavation requirements for the mining method– Excavation and ground control design analysis

• The philosophy of the ground control system,including the rationale for the type of groundsupport and reinforcement used.

• Minimum standards for ground control systemsfor each ground condition type or domain in themine

• Ground support and reinforcement layouts• Ground support and reinforcement installation

instructions (see Appendix D)• Ground support and reinforcement material

specifications (see Appendix D)• Ground support and reinforcement performance

criteria (see Appendix D))• Guidelines for when continuous and automatic

monitoring equipment may be used to monitorground conditions

• Requirements for any regular inspection programsbased on locations or specific conditions to identifyand control problems in areas where there is anincreased risk to personnel from rockfalls

• Identification of any existing or potential rockburst,seismic or other stress related problems

• A list of specific hazards and expected indicativeconditions that may be encountered for the GroundHazard Identification and Control System(see Section 3.2.4)

• The review requirements for the Ground ControlPlan. Ground control is an ongoing, dynamicprocess and the ground control systems shall bereviewed regularly when the Ground Control Planis reviewed.

Prior to authorisation, the Ground Control Plan shallbe reviewed by appropriate on-site managementpersonnel (both WMC and Contractor) and partiesexternal to that site.

1.2 Gathering Ore Body and Host Rock DataThe Ground Control Co-ordinator, in conjunctionwith geological personnel, shall coordinate thegathering of data to form geological and geotechnicalmodels.These models of the mineral deposit and the hostrock should be used when making technicalassessments.As a minimum, the Ground Control Co-ordinator, inconjunction with geological personnel, shall considerand document the following details in the GroundControl Plan:





• What does the core log information indicate aboutthe rock mass?

• What are the rock types?• What are the rock strengths and properties?• What is the historical information?• Are there any major structures or controlling

features?• What are the dips and strikes of the geological

structures (ore body and veins)?• What are the joint orientations, spacing and

properties?• What are the boundary conditions—prevailing

stress, hydrogeological regime, geomorphologicalregime, depth?

1.3 Determining the Mining Method andEquipment Options

The person delegated by the Mine Manager shall usethe information gathered in Section 1.3 to determinethe alternative mining methods and equipmentoptions.Whatever method is used, the following issues shallbe addressed in the Ground Control Plan:• What is the size of the deposit?• Do we need to go underground?• What are the alternative mining methods and

alternative mine designs, equipment, sequencingand scheduling to minimise or eliminate theexposure of personnel to particularly hazardousexcavations? The delegate shall recommend thepreferred mining method and shall prepare thefollowing details to be included in the GroundControl Plan:– A description of the excavation layouts,

orientations, sizes, shapes and type of excavationmethods in all areas of the mine for the selectedmining method

– The actual or proposed serviceabilityrequirements of each excavation

– Plans showing actual or proposed mine layouts• What are the methods to be used to develop steeply

inclined excavations. In selecting a rising method,the selection process should look at all the optionsin the order of preference of: non-entry methods,mechanised methods, other entry methods andladder rising. Alternative methods of establishingrises shall be considered in the mine designprocess and the need to use ladder rising designedout of the mining process where ever possible. Noladder rising shall be undertaken until an evaluationof all other alternatives has been carried out and arisk assessment has verified that ladder rising is theonly practicable method available

Refer to the supporting documentSAF-MHS01-R05 Ground Control Ladder RisingConsiderations for more detail of the issues thatshall be considered in the risk assessment.

• Should dedicated, purpose-built rock-boltingapparatus be used?

• What is the life of the mine?• What are the geotechnical domains (ground

conditions) within the mine?• What influence will each alternative have on the

regional stability?• What will be the heights and widths of drives, with

consideration given to stability, profile, and theability to inspect and scale the drives?

• What extraction sequence will minimise the timeany production area remains open and active?

• What are the mine design assumptions for themine?

In determining the mining method and equipment tobe used, each mine shall have in place a systematicplanning and design process and a checklist orguidelines for all mine design criteria.For example, factors of safety, extraction ratios,pillar and long hole extraction sequences, maximumpowder factors, use of down-hole in preference toup-holes, air, water, power and ventilation services,access and egress routes, excavation dimensions andany other factors which may be required by thatmine.

1.4 Designing the Excavation and GroundControl System

The Ground Control Co-ordinator shall arrange for ageotechnical evaluation to be carried out for the orebody and host rock.

1.4.1 Inrushes Major Uncontrolled GroundFailure

To eliminate the possibility of major uncontrolledground failure which could result in surfacesubsidence or inrushes of material such as water,mud, rock or fill material:• Each excavation or sequence of excavations

(where caving is not part of the miningmethod)shall be designed to be stable, and thedesign shall be based on sound geotechnicalprinciples

• Where the excavation sequencing is identified asbeing important for ground control, the excavationsequences:– Shall be stipulated as part of the design– Shall not be altered unless approved in writing by

the Mine Manager





• The procedures and processes to create theexcavations shall not be designed to induceuncontrolled instability, either locally or regionally

• During excavations, any deviations from the planor design shall be recorded, and the design re-evaluated to ensure local and regional stability ismaintained.

For all the excavations identified, a design andanalysis process shall be conducted to determine thedesign of the ground support, reinforcement and anyother ground-control procedures to be used duringthe actual excavation process.Refer to the standard SAF-MHS-09 Inrushes andSubsidence for more detail on inrushes.

1.4.2 Determining the Most Appropriate GroundControl System

In determining the most appropriate ground controlsystem, the Ground Control Co-ordinator shall takeaccount of the following:• All excavations which do not meet the

requirements of the current mine ground supportstandards for that excavation and rock type shallbe re-evaluated with regard to supportrequirements on a prioritised basis. The basis forpriorities shall be determined by a risk assessment.

• The life and serviceability of each excavation type• The feasibility of installing the ground control

system in one passThis depends on the serviceability of theexcavation using approaches such as mesh,shotcrete or other methods to reduce the need forongoing maintenance and the need to be re-supported.

• If backs are higher than 3.5 m, an inspectionplatform shall be used to identify, scale and controlrockfall hazards. Manual sounding and scalingusing an appropriate steel scaling bar is the finalmethod of scaling.

• To reduce the risk of rockfalls, perimeter blastingtechniques, type of explosive, blast holeorientation, blast hole size and patterns should beconsidered when designing and profilingexcavations

• The adequacy of the defined minimum groundsupport standards for each excavation and rocktype shall be reviewed at least on an annual basis ormore frequently if experience with groundconditions in the mine dictate.

As a minimum, the following shall be considered:• What does the core log information

(e.g. MRMR, Q, RQD) indicate about the rockmass?

• What are the joint properties, block size and shape?• What are the geotechnical regions (e.g. stress,

hydrology)?• What are the potential modes of failure?• What excavation shapes (e.g. shanty backs, arched

profile) would minimise the probability of arockfall?

• What blasting techniques, such as perimeterblasting, sequence options and pattern designs, areto be used to reduce potential instability?

• What is the optimal ground support andreinforcement technologies to control the modes offailure?

• Application of a factor of safety to be used in thedesign of the ground support and reinforcementfor various excavations?

• What are the most appropriate (i.e. serviceable,stable and practical) ground support andreinforcement designs?

1.4.3 RisingAny method of rising shall minimise the exposure ofpersonnel to a rockfall hazard.The process for designing a rise should follow thesesteps:• Determine the purpose of the rise i.e. the use for

the rise and its serviceability• Determine the size, orientation and location of the

rise based on the physical layout usage constraintsand ground conditions

• Based on the geotechnical conditions, define:– the maximum credible rockfall that could fall

from inside the rise (size and height of fall)– the ground control strategy required to control

any rockfall.• Determine the excavation method• Review the geotechnical conditions, size and

orientation and the excavation method to determineif they are acceptable

• Determine a re-entry time based on known orexpected ground conditions

• Determine the services required for the excavationof the rise e.g. water pressure, air, electricity.

If a risk assessment has verified that ladder rising isthe only practicable method available it shall be donein accordance with SAF-MHS01-R05 GroundControl Ladder Rising Considerations.

1.4.4 Raise BoringRaise boring is considered a method of rising and assuch the requirements of rising apply.





1.5 Preparing the Multi-tiered Response PlanA multi tiered response plan shall be developed whichauthorises additional ground support, over and abovethe minimum support, to be installed in response toexcavation performance. The Plan shall include arecording and analysis system and have the minimumstandards as the base line.Personnel shall be delegated specific responsibilityfor authorising each stage of the multi tieredresponse plan.

1.6 Identifying the Required ResourcesAll equipment to be used for ground control shall beidentified and listed in the Ground Control Plan.There shall be a description of each type of machinestating the purpose of the machine and all the tasksfor which it can be used. The machine shall not beused for any other tasks unless approved in writingby the Mine Manager.

2 Resourcing Requirements forGround Control

Based on the Ground Control Plan, the MineManager or nominated delegate shall define andacquire the resources to ensure quality groundcontrol work processes.

2.1 Equipment SelectionWhen selecting the equipment to be usedunderground for ground control, the Mine Manageror nominated delegate shall consider the followingpoints relating to the design, selection, operationaland maintenance requirements of the equipment:• All ground-control equipment shall meet the

requirements specified in the Ground Control Planand SAF-MHS-05 Underground MobileEquipment.

• The ground control installation equipment shallhave performance specifications and maintenanceplans. These shall be used to check and maintainthe equipment or aspects of the equipmentperformance to the specifications required withrespect to ground control installation

• The operator cabin on a bogger shall includeprotection from rockfalls from the backs andwalls, i.e. the cabin shall be of an approved FOPSdesign as a minimum

• The lighting design on a jumbo shall make thelocations to be drilled and scaled clearly visible; thecanopy shall not reduce visibility

• Jumbos shall be designed to minimise the risk ofthe operator being hit by a rockfall onto or into thecab, including by rocks deflected off the booms

• Jumbo booms used to install ground support shallbe designed to be articulated back under supportedground, as well as to install ground reinforcementto the design requirements

• Scaling machines and where a jumbo is used as ascaling machine shall have a canopy and otherprotection to stop rocks falling into the cab

• Scaling machines and where a jumbo is used as ascaling machine shall be designed to minimise thehazard from catapulting resulting from rock impacton the boom

• Portable hand-held lights, spotlights or self-standing lights shall be available to personnelengaged in ground hazard identification and control

• Platforms used for scaling shall conform to thestandard SAF-MHS-08 Safe Working at Height

• Hydraulic lines on platform-lifting equipment shallbe protected from damage

• Scaling bars shall be fit for purpose (made of steel,straight, sharp), the correct length for the job andto be adequately rigid

• Equipment shall only be used for the purpose andtasks specified (see Section 1.6).

When selecting, specifying or designing mechanicalequipment used in a rise for access or as a workplatform in a rise that equipment shall:• Have adequate overhead protection• Be designed to sustain the static or dynamic

loading associated with:– The maximum credible rockfall from within the

rise (size and height of fall)– The normal operation of the equipment

• Be designed to enable any load placed on theequipment under normal operating conditions to betransferred to the rock, and

• Be designed so that no equipment protrudes outsidethe limits of the platform during travel in the rise.

2.2 Documenting the Ground Control MaterialsSpecifications

The material specifications of all ground support andreinforcement identified in the Ground Control Planshall be documented. All ground control materialspurchased or used shall conform to thespecifications.





2.3 Developing SWPsStandard Work Procedures (SWPs) shall bedeveloped for all ground control tasks. Theprocedures shall be systematically developed (e.g.Job Safety Analysis) and be under the control of anappropriate Document Control procedure.All tasks identified in the Ground Control Plan shallbe considered when the SWPs are developed. As aminimum, SWPs shall be developed for, or includeinstructions for, the following critical activities,where they are applicable to each operation:• Visual inspection• Watering down and dust suppression• Rise and slot inspection• Scaling• Jumbo scaling• Scaling machine operation• Manual scaling and scaling from a platform

• Installing ground reinforcement• Shotcreting of the rock mass• Survey mark-up, sampling mark-up and

geotechnical mapping• Blast hole drilling• Blasting (charging and initiation)• Bogging• Rising• Ladder rising• Mechanical rising• Rise on pilot boreholes.• Raise boring• Backfilling

If other critical activities are identified, then SWPsshall be developed for them.





2.4 Identifying the Required CompetenciesAll personnel working underground shall be competent to perform the tasks assigned to them. The followingtable lists the minimum competencies required by personnel operating in ground control tasks.

Category of Personnel Competencies

All persons working in or about a rise • Know the SWP for entry and inspections for rises

All underground personnel, includingoperators, maintenance servicepersonnel, professional staff anditinerant workers

• Be literate in the language of the planning information.

• Be able to use the Location Record System which records theirunderground location.

• Be able to use the Ground Hazard Identification and Control Systemand recognise hazards specific to their work areas.

• Know the general mine layout and have detailed knowledge abouttheir workplace. (This shall be included in induction training.)

Ground Control Operators • Understand the ground support and reinforcement plans and theShift Plans.

• Recognise ground control materials, equipment or other resourcesthat are not to specifications and know how to report them.

This includes the requirement to stop their current activity if groundcontrol materials, equipment or other resources are not tospecifications.

• Have the ability to judge changes in conditions from the Shift Planand to take action appropriate to the conditions (in accordance withthe Multi-tiered Response Plan).

• Understand basic ground control principles, including regionalissues and stress-related problems. (This shall be included intraining.)

• Know all the relevant SWPs for ground support and reinforcementinstallation, equipment use and maintenance. (This shall be includedin training.)

• Be able to assess each cut after blasting to review the conditions forthe installation of the ground control system.

Ground Control Co-ordinator • Be knowledgeable in ground control theory, application and localconditions.

• Be able to understand the Shift Plan and know how to modify it ifrequired.

Rise Miner • Know all the SWPs for rising

• Adequately trained in the care and the maintenance requirements ofthe rising equipment.





3 Operations Management

3.1 Operations Planning RequirementsA regular planning process shall be in place to ensurethat there are adequate planning, resources andcontrols for ground control tasks. The planningprocess at each operating mine shall detail theactivities to be carried out on a long-term, medium-term and short-term basis as appropriate for theoperation. The planning process may take the formof regular planning meetings, at which formalminutes or notes shall be taken.The Mine Manager or nominated delegate isresponsible for preparing the operations plans.

3.1.1 Shift PlansThere shall be a daily Shift Planning meeting. Usingthe Ground Control Plan and the minutes/notes fromprevious planning meetings, the following shall beconsidered at the meeting:• The hand-over information from outgoing shift(s)• The allocation of the appropriate ground-control

resources• The reports of ground-control hazards• The allocation of ground control tasks to

personnel.

The Shift Plan shall:• Be kept in a designated location• State the minimum specifications for ground

support and reinforcement required during theshift.

The Shift Plan should utilise pictorial information toimprove communications, where appropriate.

3.1.2 Work PlansIn addition to the Shift Plan there shall be WorkPlans for specific locations in the mine and specificexcavation tasks.No excavation work is to commence in any areawithout an approved Work Plan• Work Plans shall contain references to ground

support and reinforcement instructions,specifications and expected hazards or conditions,where applicable

• Blast-hole layout and charge-up plans shall be clearand include information such as profile, location,graphical layout, hole status, charging instructionsand any expected conditions and deviations

• Shotcrete requirements shall have plans to ensurethat the work is done to the specifications

• A Work Plan for the installation of timber or steelsets, or props shall consider the exposure of theseto moving equipment.

3.1.3 Rising Work PlansThere shall be specific work plans for rising and thefollowing criteria shall be included:• Angle, length• Size, cross-sectional area• Plans and cross-sections showing adjacent

workings• Job Safety Analysis of rising method• Re-entry times• Expected ground conditions• Water pressure requirements• Services layout.

3.1.4 Ground Support and Reinforcement NotSpecified in the Ground Control Plan

Ground support and reinforcement other than thatdefined in the Ground Control Plan shall require aspecific risk assessment for that application.

3.1.5 Changes to Shift and Work PlansGround Control Operators may recommend changesto the ground support and reinforcement in the Shiftor Work Plans to improve the immediate safety ofthe working area. In line with the authority levelswithin the Multi-tiered Response Plan, these changesmay be implemented immediately provided they donot reduce the minimum support specified in theShift or Work Plan. All changes shall be recordedand reported so that they can be reviewed by theGround Control Co-ordinator.

3.2 Ground Control Monitoring and EvaluationSystems

3.2.1 Location Record SystemEach mine shall use a Location Record System torecord the location of personnel underground,including visitors. A system shall also be in place tocontrol access to hazardous areas.The system shall be located on the surface and bereadily available to all personnel.

3.2.2 Mine and Work Area Layout PlansAll personnel shall have ready access to plans,sections and maps which show the overall generalmine layout and specific work area layouts. Theseplans, sections and maps should also indicate groundcondition occurrences such as:• Hazardous or changing ground conditions





• Significant ground falls• Failure of ground support and reinforcement• Rock stress relief or conditions.The Mine Manager or the delegate shall review andupdate the layout plans as required.

3.2.3 Workplace Inspection and ReportingThere shall be regular inspections of the workplaceto identify and report hazards. The Shift Supervisor:• Shall inspect each underground workplace at least

once in each shift to ensure that work is beingconducted as specified in the Shift and Work Plans

• May make more frequent inspections, dependingupon the regulatory or management requirementsof the system under which the mine operates

• Shall report hazardous conditions identified duringthe inspection using the Ground HazardIdentification and Control System.

3.2.4 Hazard Identification and Control SystemTo record, report and control hazards identifiedduring visual inspections there shall be a HazardIdentification and Control System in place that:• Identifies indicative or site specific conditions that

may indicate a hidden hazard• Indicates nature of hazard at the time it was

identified• Defines the action to be taken for certain specified

conditions• Provides details of all identified hazardous

conditions, whether acted on or not, for inclusionin the Ground Conditions Model

• Requires feedback to initiator if hazard is fixed byanother person.

The Ground Control Co-ordinator shall use a GroundHazard Identification and Control System to record,report and monitor ground control requirements.(see Appendix E Example of a Ground HazardIdentification and Control System)The information from the Ground HazardIdentification and Control System shall be used forplanning and design of ground-control measures.The Ground Control Co-ordinator, Shift Supervisorsand the managers of Ground Control Operators shallbe familiar with the system and the GroundConditions Model.The Ground Control Co-ordinator shall coordinatethe Ground Hazard Identification and ControlSystem.

3.2.5 Ground Conditions ModelThere shall be a Ground Conditions Model for themine which can display the information collected inthe geotechnical data base and that enables the minemanagement to build a record of ground conditionsencountered at a mine to:• Check, modify and review ground support and

reinforcement plans and the Ground Control Plan(e.g. optimisation, safety)

• Gather information for subsequent mining activitiesin previously developed areas

• Gather information on stability problems soexposure to hazards can be managed.

The following points relate to the construction of theGround Conditions Model.• The Ground Conditions Model should be based on

information contained in the Ground Control Planand updated with information from the various datagathering methods

• The recording system for the Ground ConditionsModel should be selected to suit the mine and mayrange from simple two-dimensional plans withoverlays to complex three-dimension plans on aCAD package

• The complexity and number of componentconditions recorded in the Ground ConditionsModel should suit the mine. Examples ofcomponent conditions are:– Structural geology (e.g. blocky, jointed, layered)– Rock Mass Quality Rating (e.g. red, green, 1 to

10, Q or RMR)– Blast quality (e.g. overbreak, damage, problems)– Installed ground control system (e.g. standard

type 1, 2, 3 etc. or blue, green, red etc.)– Adverse ground conditions (e.g. excessive scats,

rockfalls, water, rock bursts, stress).The Ground Control Co-ordinator shall beresponsible for developing, maintaining andmonitoring the Ground Conditions Model.

4 Ground Control Tasks

4.1 Mandatory Requirements for WorkConducted in a Mine

The following requirements are mandatory for anywork conducted in the mine:• No person is to go beyond supported ground,

i.e. ground supported or reinforced to an approvedstandard for that rock type and made safe





• No person is to enter an area without theknowledge of the Shift Supervisor or withoutrecording his/her location in a Location RecordSystem to which the shift supervisor has access.The information should be provided either prior tothe shift commencing or during the shift and inaccordance with any hazard signage procedure inplace

• As hazards are identified during any task in thework cycle, scaling or other appropriate actionshall be taken immediately

• Personnel shall not be allocated or undertake tasksfor which they have not been assessed ascompetent by the Mine Manager or nominateddelegate, unless they are working under directsupervision of a competent person.

4.2 Re-entry RequirementsPrior to accessing inactive areas or followingproduction or development blasting there shall be are-entry procedure that includes;• Visual inspection• Watering down and dust suppression• Scaling

4.2.1 Visual inspectionWhen entering a heading, personnel shall completethe following actions:• Check the visibility; if the excavation surface is not

visible, personnel shall not enter• Look for evidence on the floor of rockfalls• Look for loose rock between rock bolts• Inspect the previously installed ground support and

reinforcement• Look for any signs of rockburst or high stress

conditions• Look for loose material behind vent bags and

obstacles• Look for and obey the instructions implied by

barriers.

4.2.2 Rise and Slot Inspection• Travel shall be from above rather than below,

where practicable• Persons who are permitted to enter a rise shall be:

– The miner assigned to that rise– Any other person authorised in writing by the

Underground Manager for the purpose of makingthe rise safe

– Other persons, only if the rise miner or anauthorised person is present and then only withthe knowledge and consent of that person

4.2.3 Watering Down and Dust Suppression• Initial watering down and scaling of an excavation

after blasting shall be from a supported and safelocation

• If rock burst or heat conditions are identified in theGround Control Plan or by observed groundconditions, a special SWP shall be developed forwatering down and scaling in these areas

• Service crews shall be provided with guidelines forinstalling valves and hoses; the guidelines shallinclude the inspection of the installation area forrockfall hazards.

4.3 Scaling• Boggers shall not be used for scaling the backs of

the excavation. The bucket may be used to push-off rocks on the walls provided the rock is nohigher than the mid point height of the cab of theloader. In using this technique, in addition to thesafety aspects, the consequences of possibledamage to the loader must be considered. Use of abogger to scrape the walls shall not be the sole orfinal method of scaling; manual sounding andscaling is the final method

• Hand-held drills shall not be used for scaling• The SWPs relating to scaling shall not

unnecessarily expose existing and required groundsupport and reinforcement to damage from thescaling process

• There shall be a process in place to repair orreplace ground support and reinforcementdamaged by scaling.

The above requirements shall also apply to thescaling activities specified below.

4.3.1 Jumbo Scaling and Scaling Machines• Equipment shall be positioned so that there is an

adequate and safe retreat and work area• Scaling shall be conducted from a safe area while

advancing to the face• Booms should be kept to a minimum angle to

reduce the risk of a rock bouncing into the cab• Personnel shall not approach past the rear of the

jumbo or scaling machine while it is operatingwithout the consent and knowledge of the operator

• Use of a jumbo or a scaling machine shall not bethe sole or final method of scaling; manualsounding and scaling is the final method, unless theGround Control Plan specifies an alternativemethod of scat control e.g. mesh or shotcrete.





4.3.2 Scaling from a Platform• There shall be a system to enable continuous

communication by visible signals or verballybetween personnel in the platform and theequipment operator

• The use of platforms shall comply withSAF-MHS-08 Safe Working at Height

• Only one person on a platform shall scale at onetime

• Hydraulic lines on a platform lifting mechanismshall be inspected before and after use of theplatform by the operators.

4.3.3 Manual Scaling• If a loose rock cannot be manually scaled, work

shall stop, the location shall be marked, reported,and appropriate action shall be taken

• When in doubt, personnel shall get a secondopinion or assume the worst reasonable case andreport it

• While scaling, personnel shall not positionthemselves where they are subject to risk

• Personnel shall be made aware of any specifichazards in wet slippery conditions

• Personal shall be made aware of any specifichazards when working in a confined area

• When sounding, other noises should be stopped, ifpracticable

• Scaling bars shall be fit for purpose (made of steel,straight, sharp), the correct length for the job andto be adequately rigid. When considering theappropriate length of the scaling bar, the operatorshould be positioned well clear of the rock beingscaled, with the bar used by the side of the bodyand at an angle of 45 degrees. For general scalingsituations such as when scaling the walls andbacks from ground level this would require a barof around 2 metres in length. In smallerexcavations or when scaling from a platform closeto the backs it may be necessary to use a shorterbar that suits the situation and the manoeuvrabilityavailable. Consideration should be given to the useof central deflector rubber to reduce the possibilityof rocks sliding down the bar onto the operatorshands

• If backs are higher than 3.5 m, scat bars may beused in isolated circumstances to knock downloose rocks that have formed after the scalingprocess has been completed. These scat bars shallnot be used for scaling and the use of a scat barcannot be considered the sole or final method ofsounding and scaling.

4.4 Inspecting Ground Reinforcement• A competent person shall assess each cut after

blasting to review, record and feedbackinformation on conditions for updating the GroundConditions Model and the Ground Control Plan

• The Ground Control Operator shall judge changesin conditions if they are different from thosespecified in the Shift Plan and take actionappropriate to the conditions as per the Multi-tieredResponse PlanNote: The change shall be recorded and reportedso that it can be reviewed by the Ground ControlCo-ordinator.

• Each specific type of support, mesh, all rock bolts,cable bolts etc. shall have a separate SWP. TheSWP shall:– Include installation instructions, criteria for each

ground reinforcement type– Reference the ground reinforcement material

supplier’s installation instructions,• Problems with ground control materials and/or

installation shall be noted and reported back• Hole specifications shall be provided to the Ground

Control Operator.• Where necessary a template for the correct sizing

of drill bits shall be used for each specific rocktype and ground reinforcement type. Only bitswhich meet the requirements shall be used forground control installation

• Where necessary bits shall be colour-coded, or asystem of notches cut into the bit to indicate bitsize, for the required application of rock type andground reinforcement type

• Consideration shall be given to occasions whenground reinforcement is being installed in a wetbore hole

• Consideration shall be given to the appropriatenessof drilling multiple holes for ground reinforcement

• Persons shall work under supported ground whenchanging bits, rods or ground reinforcementelements

• Scaling and boring shall not be carried out at thesame time

• Personnel shall not go out under unsupportedground to find a hole which is difficult to locate

• Hand-held lights shall be available to find holes

All repairs or maintenance on equipment which mayexpose personnel to rockfalls shall be done fromunder supported ground.The Ground Control Co-ordinator shall have accessto the SWPs for ground reinforcement installationinformation.





4.5 Shotcreting• Pre-shotcrete inspection and preparation shall be

undertaken to ensure rock conditions are suitable• • No shotcreting shall be undertaken without a

relevant workplan• Any shotcreted area shall be considered as

unsupported ground until the elapse of theminimum curing time required by the mixspecification

The area shall be barricaded with the appropriatesignage until cleared for access 4.6 Blast-hole Drilling• The face shall be scaled and cleaned prior to

drilling• Appropriate multiple drilling procedures shall be

used• Drilling shall be completed to the design pattern• Blast-hole drilling shall include the practice for

digging out the lifters• The face shall be marked up to drill.

4.7 BlastingBlasting includes charging, detonator connection andinstallation and initiation.• The work area shall be checked and re-scaled prior

to charging up• There shall be documented charge-up procedures

for all blasting operations• The face shall be charged from the top of the face

down• Charging shall only be from one level of the face at

a time• Connection of the initiation system shall commence

from the top down• The procedures for connecting to the firing line

shall not expose personnel to a rockfall hazard.

4.8 Bogging• Before bogging and before clean-up, the operator

shall get out of the bogger and conduct a visualinspection

• The face shall be scaled and the ground supportshall be in place to protect the operator whendigging out the lifters

• If rail bogging, scaling shall continue as boggingadvances.

4.9 Rising• An adequate area at the entrance to a rise shall be

barricaded and sign posted as an exclusion zone• Any visitor or observer shall remain outside the

exclusion zone while persons are accessing orworking in the rise

• No person shall approach within the exclusion zoneor access the rise while work is in progress orequipment is being transported in the rise.

• The entrance to the rise shall provide clear and safeegress to and from the rise and enable a person tostand at the base of the rise for visual inspection

• There shall be a spray system to flush the rise priorto entry after blasting. This system should be ofsteel pipe and utilise water as one part of theflushing process

• The control valves for the flushing system shall belocated outside the exclusion zone

• An adequate source of light shall be used tovisually inspect the face, backs and walls of therise

• The face shall be scaled before boring commences• There shall be a system of communicating with the

miner whilst working in the rise• If any services or equipment are less than adequate

then operations shall stop until these can bereturned to normal

• There shall be installation instructions for allequipment used

• Any platform installation shall enable the miner toreach the face, to scale and carry out the workrequired in the rise

• There shall be a method for transporting equipmentinto the rise

• A fall restraint system shall be employed whilstrises are being excavated

• At any breakthrough a suitable exclusion zone shallbe clearly defined and barricaded.

• Prior to entry a visual inspection shall be carriedout

• There shall be clear instructions as to what actionsto take in the event that the visual inspectionindicates a hazard and which do not exposepersonnel to unacceptable risk with regard torockfall hazards

• There shall be a system to report any problems ordeviations from the work plan

4.9.1 Ladder RisingAny ladder rising shall be done with the appropriatework procedure which complies with therequirements of SAF-MHS01-R05.





4.9.2 Mechanised Rising• Only one miner shall scale at a time• Where a multi-decked stage is used drilling should

only occur on one deck at a time.

4.9.3 Rise on Breakthrough Pilot Boreholes• No person shall enter a rise until the pilot borehole

has been checked and is clear• If the pilot borehole is blocked, a JSA shall be

conducted before any work is undertaken toremedy the situation

• All pilot boreholes shall be sign posted, barricadedand be protected so as to stop any material or fluidfrom accidentally falling down the pilot hole or toprevent access at firing times.

4.9.4 Raise BoringNo work shall be conducted in or below the raisebore hole unless supported to the minimum standardor overhead protection is provided

4.10 Use of ChecklistsThe Ground Control Co-ordinators and GroundControl Operators shall use appropriate checklistswhen assessing the quality of the ground support orreinforcement installation.

4.11 Survey Mark-Up, Sampling Mark-Up andGeotechnical Mapping

Special consideration shall be given to surveyors,samplers, geologists and other infrequent visitorswho visit the faces on an irregular basis for tasksincluding set up from a survey control, face markup, mapping the area, collecting samples, etc.Surveyors, geologists, samplers and other infrequentvisitors shall be familiar with the Shift Plan, and beprovided with relevant information on localconditions before entering a work location.

5 Monitoring the Ground ControlPlan

There shall be in place a system for auditing andchecking processes to ensure that the system isworking correctly.

5.1 Monitoring Compliance with the GroundControl Plan

The Mine Manager is responsible for ensuring that anauditing process is in place to:

• Monitor on a regular basis as appropriate to themine the SWPs for ground control

• Check the quality of ground control materials andground support or reinforcement installation atrandom locations throughout the mine at least oncea month. (This is to be done by a competentperson)

• Record the locations throughout the mine whereexisting support or ground conditions are to bemonitored (refer to related documentSAF-MHS01-R01 Ground Control InspectionChecklist for guidelines).

• Feed back to the Ground Control Operator via theGround Control Co-ordinator any results of groundsupport or reinforcement methods monitoring.

5.2 Monitoring the Effectiveness of GroundControl Plan

To enable the effectiveness of the Ground ControlPlan to be monitored, the following shall be in place:• A system for recording ground support and

reinforcement failures and deviations fromexpectations, as well as a process for reviewingthe failure or deviation and taking appropriateaction

• Testing systems specifically designed for each typeof ground control (including wherever possiblephysical testing)As a minimum, 0.1% of newly installed groundsupport or reinforcement in each rock type shall betested against the performance criteria in theGround Control Plan. Testing shall be undertakenon a random basis and the interval between thetests shall not exceed three months

• A process for reviewing any continuous andautomatic systems for monitoring of rockconditions to indicate hazardous changes notvisible (part of ground hazard identification andcontrol system), including SWPs for installationand use of continuous and automatic monitoringsystem

• A regular inspection program of defined locationsand specific conditions to identify and controlproblems in supported areas where there is anincreased risk to personnel from rockfall hazards

• A regular inspection and monitoring program ofdefined locations for areas where there is anidentified risk of uncontrolled ground failure whichcould result in surface subsidence and inrushes.





APPENDICESAPPENDICES

A Definitions

Abbreviations

FOPS Falling Objects Protection System

GC Ground Control

MRMR Modified Rock Mass Rating

MSDS Material Safety Data Sheet

Q Tunnelling Quality Index

RMR Rock Mass Rating

RQD Rock Quality Designation

Terms

Competence Demonstrated understanding and application relating to a documented Standardwhich is personally acknowledged in writing.

Ground ConditionsModel(GCM)

A Ground Conditions Model is a database or recording system that allowsengineering, geotechnical and operational staff to record and review all aspectsassociated with the conditions encountered underground.

Ground Control A combination of controlled blasting, scaling, ground support and groundreinforcement to influence the rockmass.

Ground Control Plan(GCP)

A plan that covers all the planning and design requirements for the managementof ground conditions at the mine or operation.

Ground reinforcement Elements applied to the interior of a rockmass to limit movement of the rockmasse.g. rockbolts, cablebolts

Ground support Elements applied to the perimeter of an excavation to limit the movement of therockmass e.g. steel sets, timber props, shotcrete

Multi-tiered ResponsePlan

A plan or system of ground control that provides for the enhancement of the levelof reinforcement and ground support, if necessary.

Practicable Technically feasible, economically justifiable and contributing to the reduction ofrisk.





Rise/Raise A vertical or steeply inclined development opening driven or excavated upwardfrom a level in an underground mine. For the purpose of the GCS a rise is adevelopment excavation at an angle greater than 35º. The provisions for ladderrising in the GCS do not apply to hand held stoping methods unless these stopesare at an angle greater than 35º and there is not a means of approaching the facewithout travelling up under the freshly fired face

Rockfall hazard An uncontrolled displacement (due to gravity or stress) of material (rock orsupport elements) from the surface of the excavation.

Scaling Scaling is the action of levering/prising out loose rocks from the backs, walls andface of an excavation. Scaling bars should be made of steel in order to beadequate for sounding the rock and strong enough to lever the loose rocks free.

Scat removal Scats are small (generally up to around 200mm x200mm ) loose rocks which can beeasily removed from the backs and walls of an excavation or from behind the meshby knocking with a scaling or scat bar. Scat bars may be made of light weightmaterial such as aluminium and of a length such that the backs of the excavationcan be reached with the bar held at an angle of 55º to the horizontal (Using a 3.6mscat bar the maximum height of backs which could be reached is 4.5m ). A scat barshall not be used for scaling and shall only be used to control scats after scalinghas been completed. Removal of scats shall not be considered as the sole or finalform of scaling.

Serviceability Fit for purpose for the required life.

Shall, should and may Shall: A mandatory requirement i.e. a requirement that is to be met at all times.

For new equipment, processes and systems, this requirement must bemet.

For existing equipment, processes and systems, the requirement must beaddressed in an implementation plan which has been approved by theResident Manager or equivalent. There must be evidence of progressiveimplementation according to this plan.

Should: An advisory requirement i.e. a requirement that is to be met wherepracticable.

Where the requirement is not implemented, the justification fornon-adoption and evidence of an alternative solution shall be provided.

May: A discretionary requirement i.e. the person authorised to make ajudgement is to use their discretion.

Shift Plan A plan of the activities that will occur during a working shift at the mine, whichidentifies:

• Where the activities are to occur

• Who is to do what task

• What equipment is to be used

• What hazards have been identified in the area relevant to the task that is to beperformed.





Supported Controlled to an approved standard and made safe through the appropriate use ofcontrolled blasting, scaling, ground support and ground reinforcement.

Each excavation and rock type shall have defined minimum approved supportspecifications (e.g. stable spans, minimum ground support, minimum groundreinforcement spacings and types, specifications for installation, specificationsfor ground reinforcement elements). In certain circumstances ground may beconsidered supported when no ground support or reinforcement is installed. Inthis case a geotechnical evaluation would have been undertaken to determine thata situation does not exist which may possibly result in a rockfall or otherwiseaffect the stability of the excavation. In pre-existing areas of the mine, historicalperformance of the ground would also be considered.

Work Plan A set of work instructions for specific locations in a mine. It usually includes asurvey plan of the proposed work area identifying geotechnical or other relevanthazards.

B Related DocumentsSAF-MHS-05Underground Mobile EquipmentSAF-MHS-08Safe Working at HeightSAF-MHS-09Inrushes and SubsidenceSAF-MHS01-R01Ground Control Inspection ChecklistSAF-MHS01-R05Ground Control Ladder Rising Considerations

C Revision Information.

Revision 2 issued 19/06/00



Section DifferencePurpose and Scope Wording amended

1.1 Producing the GroundControl Plan

Dot point eleven add “Ground”

1.3 Determining theMining Method andEquipment Options

Paragraph one and two amended and merged

1.4.1 Major UncontrolledGround Failure

Changed from “Inrushes”





Section Difference1.4.2 Determining the Most

Appropriate GroundControl System

Renumbered and this whole section has been moved from 1.4.4. Wording not changed.

1.4.3 Rising Renumbered and last paragraph added.

1.4.3 (Previously) LadderRising

This section has been removed

1.4.4 Raise Boring Section added

1.5 Preparing the Multi-tiered Response Plan

Wording amended

2 ResourcingRequirements forGround Control

Wording amended

2.1 Equipment Selection Heading changed. Dot points one, two, six and nine amended.

2.3 Developing SWP’s First paragraph amended. Ninth dot point amended. Last two dot points added.

2.4 Identify the RequiredCompetencies

Word “Ground” added to Hazard Identification

3.2.3 Workplace Inspectionand Reporting

Add word “Ground”

3.2.4 Ground Hazard andIdentification andControl System

Change heading. Amend wording

4.2 Re-entry Heading changed. Paragraph added.

4.2.1 Visual Inspections Heading changed.

4.2.3 Watering down andDust Suppression

Numbering changed from 4.3. Wording amended.

4.3 Scaling Numbering change from 4.4

4.3.1 Jumbo Scaling andScaling Machines

Numbering change from 4.4.1.

4.3.2 Scaling from aPlatform


4.3.3 Manual Scaling Numbering change from 4.4.3.

4.4 Inspecting GroundReinforcement

Numbering change from 4.5. Wording amended.

4.5 Shotcreting Dot points removed and alternatives added

4.6 Blasthole Drilling Numbering change from 4.7.





Section Difference4.7 Blasting Numbering change from 4.8.

4.8 Bogging Numbering change from 4.9. Second dot point removed.

4.9 Rising Numbering change from 4.10. Three new dot points added

4.9.1 Ladder Rising Numbering change from 4.10.1. All previous wording removed and new paragraphadded.

4.9.2 Mechanised Rising Numbering change from 4.10.2.

4.9.3 Rise on BreakthroughPilot Boreholes


4.9.4 Raise Boring Wording amended

4.10 Use of Checklists Numbering change from 4.11.

4.11 Survey Mark-up,Sampling andGeotechnical Mapping

Numbering change from 4.12.

5.2 Monitoring theEffectiveness of GroundControl Plan

Dot points two and four amended.

A Definitions “Raise” added to “Rise”

D Example of GroundReinforcementInstallationInstructions

Sub headings amended

E Example of a GroundHazard Identificationand Control System

Heading changed. Word “Ground” added to first paragraph and flow chart.

F The principleComponents of aReinforcement System

Removed





D Example of GroundReinforcement InstallationInstructions

(This accompanies the SWP for the specific supportor reinforcement type.)

The process of installing ground reinforcementinvolves seven steps.The process is explained below. Each action includesat the start and end of that task the requirement toconduct a ground hazard identification, assessmentand take appropriate action.

Step 1. Obtain the correct Work Plan.The plan may be specific to each excavation.

Step 2. Assemble, and check the equipment andmaterials.

The installation equipment required toachieve a quality installation to thespecification set out on the Ground ControlPlan should be assembled. This equipmentshould be checked for safe operation,correct function, dimension and, ifnecessary, calibration.

The required ground reinforcement (orcontrol) materials specified in the GroundControl Plan must be assembled.Unacceptable variations should be rejected.Acceptable or unavoidable variations shouldbe recorded and input into the GroundConditions Model.

General criteria for inclusion into a checklistare given below in terms of the threedifferent generic types of rock bolt.

Criteria for Friction Rock Stabilisers

Geometry: DiameterLengthType

Conditions: CorrosionDamage

Materials: Check tags and labels

Compatibility: Plates/elements.

Criteria for Fully Grouted Devices

Geometry: DiameterLengthTypeThreads/nuts/washersPlate


Materials: Tags and labels checkAge and use by date of cements and resinsPackaging

Compatibility: Plates/elementsWashers and nutsExpansion shellsWater and cementResin and rock type.

Criteria Point Anchored Devices

Geometry: DiameterLengthTypeThreads/nuts/washersPlate


Materials: Tags and labels checkAge and use by date of

resinPackaging

Compatibility: Plates/elementsWashers and nutsExpansion shell type and size.

Step 3. Drill the holes and/or prepare the surface.

The holes for reinforcement must be drilledin the correct position, and be of the correctorientation and dimensions. For support ofshotcrete, mesh, etc., the surface may needto be carefully cleaned down.





Step 4. Install the ground reinforcement.

The ground reinforcement must be installedaccording the SWP for that groundreinforcement type, and any specialinstructions that might be required by theGround Control Plan must be followed.

Step 5. Make the final adjustment of groundreinforcement.

The final adjustment or modification mayinclude post-tensioning, post-grouting,placing extra bolts to pin straps and mesh,application of curing sprays on shotcrete,etc. These tasks must be treated with thesame care as during the initial installationstage, and will often involve specialinstructions in the Ground Control Plan andin the SWP.

Step 6. Check the installation and groundconditions.

The Ground Control Operator must ensurethat the ground reinforcement has beeninstalled according to the Ground ControlPlan, but has not (regardless of the Plan)inadvertently produced a hazardouscondition.

Step 7. Record ground conditions and groundreinforcement conditions.

It is important to record the groundconditions, the condition of the installedground reinforcement and any variations ordifficulties encountered during installation.This information is vital for the GroundConditions Model. A record of no variationsor no difficulties is equally as important.

Obtain correct plan

Assemble and check materials and equipment

Drill holes and/or prepare surface

Install ground support

Pretension or adjust as required

Check installation and ground conditions

Record conditions and/or variations

Hazard identification assessment and action

The Ground Control Installation Process





E Example of a Ground Hazard Identification and Control SystemThe Ground Hazard Identification and ControlSystem involves a process of five basic steps. Theprocess is explained below.

Step 1. Inspection Schedule.

An inspection schedule must be set up forexcavations used for production andinfrastructure. The timetable for theinspections should be according to the riskand planning information.

Step 2. Inspection, Identification and Assessment ofGround Conditions and Hazards.

The inspection should be conducted as perthe schedule. The person making theinspection should consider items general toall excavations and items specific to aparticular site. Some of these items are listedbelow and the features highlighted in boldare considered to be minimal features forwhich all personnel should have skills torecognise.

Ground Conditions• Excessive stress conditions• Cracking, ticks and boots• Block shapes and sizes (hazardous shape

and size)• Structure (hazardous predisposition in

relation to excavation)• Pendants (partly bounded by joints or

fractures)• Unravelling conditions• Squeeze and bulge conditions• Spalling and seismic conditions• Complex 3-D excavation shapes• Undercut walls and pillars• Sounding rock• Closure of joints and holes• Extrusion of joint fillings• Water from joints, holes, staining• Overbreak• ‘Dog ear’ overbreak in excavation corners• Arching• Buckling and kinking of layers• Blast percussion zones• Blast fractures

• Partly stripped holes.Ground Reinforcement• Deformation of external fittings• Corrosion• Hung-up rock in mesh and mesh baskets• Shotcrete - hollow drumminess• Shotcrete - cracking, flaking• Sounding elements, plates and fittings• Hung-up blocks and scats• Twisting of strand devices• Seepage• Lüder lines on plates• Breaking of mesh welds• Yielding of wires of mesh• Tearing of mesh at bolts• Shotcrete - seepage• Shotcrete - discolouration• Shotcrete - leaching of salts.

Step 3. Recording the Ground Condition Hazards.

A form that allows the easy recording ofconditions and variations should be preparedfor the site. The form should include thegeneral and specific list of points associatedwith the ground conditions at that site.

Step 4. The Ground Condition Hazards.

The ground condition hazards must beproperly communicated, both by verbal andwritten communication depending on thehazard severity. The ground conditionhazards must also be permanently recordedin the Ground Conditions Model.

Step 5. Tactical or Strategic Action.

Strategic or tactical action, or both, may berequired for some conditions, depending onthe nature and severity of the situation.• Tactical action involves the implementation

of measures, usually physical, to addressthe situation

• Strategic action involves furtherinvestigation or research to decide on themost appropriate physical change toimplement.

The process requires that the effect of the tacticalaction be continually monitored.





Inspection schedule for excavations

General & specific features

Inspection, identification & assessment of GC &

hazards

Communication & reporting of potential

hazardsStrategic action

Ground conditions

model

Recording of GC & hazards

Tactical action

The Ground Hazard Identification and ControlSystem

Documents

Underground Ground Control - · PDF file4.5 Shotcreting ... Underground Ground Control ** Uncontrolled copy. Use latest revision ** ... pillar and long hole extraction sequences, maximum

Underground Ground Control - · PDF file4.5 Shotcreting ... Underground Ground Control Uncontrolled copy. Use latest revision ... pillar and long hole extraction sequences, maximum