The Application Of Major Hazard Risk Assessment (MHRA) To .

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IC 9508INFORMATION CIRCULAR/2008The Application of Major HazardRisk Assessment (MHRA) toEliminate Multiple FatalityOccurrences in the U.S. MineralsIndustryDepartment of Health and Human ServicesCenters for Disease Control and PreventionNational Institute for Occupational Safety and Health

Information Circular 9508The Application of Major Hazard Risk Assessment (MHRA) toEliminate Multiple Fatality Occurrences in the US Minerals IndustryBy A. Iannacchione, F. Varley and T. BradyDEPARTMENT OF HEALTH AND HUMAN SERVICESCenters for Disease Control and PreventionNational Institute for Occupational Safety and HealthSpokane Research LaboratorySpokane, WAOctober 2008

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Table of ContentsAbstract .1Executive Summary.2Acknowledgement.31.0 - Introduction .31.1 – Trends in Managing Major Mining Hazards .42.0 – Minerals Industry Risk Management.52.1 – The US Experience .52.2 – The Australian Experience .62.3 – Has the Risk Management Framework Worked to Reduce Miner Injuries? .72.4 – The Minerals Industry Safety and Health Centre (MISHC).83.0 – Risk Assessment and Analysis Techniques and Tools .93.1 – Risk Assessment Techniques .93.2 – Risk Analysis Techniques and Tools .114.0 – Elements of an MHRA .174.1 – Risk Assessment Design (Scoping) .174.2 – Risk Assessment Team .174.3 – Risk Assessment.184.4 – Effectiveness of Controls.204.5 – Audit and Review .225.0 - MHRA Pilot Studies at US Underground Mining Operations .235.1 – Rock Reinforcement Process Risk Assessment Case Study .245.3 – Spontaneous Combustion Causing Fire/Explosion Risk Assessment Case Study.335.4 – Underground Workshop Fire Risk Assessment Case Study .405.5 – Water Inundation Risk Assessment Case Study.495.6 – Escapeway Egress Blockage Risk Assessment Case Study.585.7 – Natural Gas Ingress Risk Assessment Case Study .675.8 – Conveyor Belt Fire Risk Assessment Case Study.775.9 – Longwall Gate Entry Track Fire Risk Assessment Case Study.875.10 –Change of Mining Method Risk Assessment Case Study .956.0 – Lessons Leaned .1106.1 - The Scoping Document .1106.2 - The Risk Assessment Team .1106.3 – Important Risk Assessment Tools and Techniques.1116.4 - The Risk Assessment Team Outputs (Identified Controls).1126.5 – Documentation.1127.0 – Success of Risk Assessment Case Studies.1147.1 – Existing Risk Management Culture.1147.2 – Risk Assessment Design .1157.3 – Risk Assessment Team .1157.4 - The Risk Assessment Process.1167.5 – The Extent of Existing Controls.1167.6 – The Quality of New Ideas.1178.0 – Future Use of the MHRA Process in Mining .1189.0 – References .121APPENDIX B – Action Plan of New Ideas.127iii

APPENDIX C – Risk Register.128APPENDIX D - Risk Management Culture and Self-Assessment.129IllustrationsFigure 1 - Cumulative multiple fatalities over the last 10 years in the US Minerals Industry. .4Figure 2 - Principal risk management framework used in Australia.7Figure 3 - The running three-year underground mine fatality rates for Australia and the US. .8Figure 4 - An example of a WRAC risk ranking form.11Figure 5 - The Preliminary Hazard Analysis (PHA) Form. .12Figure 6 – Item-by-item risk assessment worksheet for FMEA.13Figure 7 - Process analysis form for a HAZOP.14Figure 8 - Bow Tie Analysis (BTA) method.15Figure 9 - Example MHRA team structure (MISHC, 2007). .18Figure 10 - Drill used to install rock reinforcement. .26Figure 11 - Photograph of shock cords similar to the ones used at the study site.31Figure 12 - Bleederless ventilation system used at the study mine to control spontaneouscombustion. .34Figure 13 - Distribution of prevention controls and recovery measures for the spontaneouscombustion causing fire/explosion risk assessments.37Figure 14 - Map showing the location of the maintenance pit with respect to track haulage,ventilation stoppings, and intake shaft. .40Figure 15 - Distribution of prevention controls and recovery measures for the undergroundworkshop fire risk assessment. .45Figure 16 - Location of Mines Ea and Eb and adjacent water-filled abandoned mine andwater/gas filled adits.49Figure 17 - Location of geographic boundaries of the risk assessment. Thick lines define theboundaries between the abandoned mines and the current projections for Mines Ea and Eb.51Figure 18 - Graphical depiction of the BTA used in the inundation risk assessment. .53Figure 19 - Techniques used to find the location of water-filled old mine workings. .54Figure 20 - Distribution of prevention controls and recovery measures for the water inundationrisk assessment. .57Figure 21 - Escapeways, roof falls and recent roof cracks found at the mine.58Figure 22 - Six segments of the mine's escapeway system. .60Figure 23 - Roof Fall Risk Index (RFRI) measured in the mine's escapeways.61Figure 24 - Distribution of prevention controls and recovery measures for the escapeway egressblockage fire risk assessment. .66Figure 25 - Mine Ga layout showing the location of active faces, the slope and panels within oneactive level.67Figure 26 - The risk assessment team created this schematic to illustrate the hazards andpathways related to the study mines.69Figure 27 - Detailed view of the ventilation circuit used at Mine Ga. .70Figure 28 - BTA for mining into an existing oil/gas well top event. Potential causes are listed onthe left side of the bow tie with potential recovery measures on the right.71Figure 29 - Distribution of prevention controls and recovery measures for the natural gasinundation risk assessment. .76iv

Figure 30 - Mine H layout showing the location of the conveyor belt and working faces. .77Figure 31 - Segments of the conveyor belt system.78Figure 32 - Conditions within the cribbed area of conveyor belt Segment #2.82Figure 33 - Distribution of prevention controls and recovery measures for the conveyor belt firerisk assessment. .86Figure 34 - Site conditions at Mine I showing the 3-entry development panel with direction ofair flow.87Figure 35 - Distribution of prevention controls and recovery measures for the longwall gateentry track fire risk assessment.90Figure 36 - Diagram of Captive Cut-and-Fill mining method.95Figure 37 – A flow chart of the basic stope proposal and mine planning process. .105Figure 38 - Distribution of prevention controls and recovery measures for the captive cut-andfill change of mining method risk assessment.109Figure 39 - Percentage of the total controls by category.112Figure 40 - Steps along the path to an improved safety culture. .132TablesTable 1 - Hazard types associated with multiple fatality events in the US Minerals Industry,1997-2007.5Table 2 - A generalized risk matrix used in many qualitative risk analysis techniques. .9Table 3 - Examples of variable scales used to determine the maximum reasonable consequenceassociated with different kinds of unwanted events. .12Table 4 - Examples of variable scales used to determine the likelihood of occurrence