CSMM101 – Hazard and risk managementBow tie method for risk assessment Bow tie method for risk assessment of possible explosion in a coal mine Hazard Threat 1. 2. 3. Puncturing of a methane Pocket in the coal seam Control Measures Drainage of entire coal seam Drainage of proposed coal seam before working Drilling of test holes to search for gas pockets in mine Continuous monitoring of methane concentration at seam using gas detectors Pre – mining drainage monitoring to identify gassy seams 1 Stored Methane Accumulated coal dust Electrical Machineries 4. 5. E x p l o s i o n i n t h e m i n e 1. 2. 3. 4. 5. 6. 7. 1. Coal as a combustible Heat and fire due to friction People 2 Mechanical Energy Stored water Methane Inundation from floor/roof 2. 3. 4. 5. 6. Drainage of entire coal seam Drainage of coal seam above and below the active working Appropriate pillar design to prevent floor heaving Scaling of floor and roof Gas detectors at intervals in mine Visible inspection for zones of weakness (on – shift/Pre Shift) 1. 2. 3. 4. 5. 6. 7. 8. 3 Accumulation of Methane on roof of 1. Pre Shift/on shift evaluation of roofs using potable gas 1. Recovery Measure Evacuation of the workers at mine Shutting down of stopping doors/airlock Increased flushing of fresh air to dilute excess methane Termination of power supply to equipment Emergency Response plan in action Mine Rescue team on standby All employees equipped with Self contained self rescuers Evacuation of Workers at mine Sealing of affected areas with stoppings/airlock Increased flushing of fresh air to dilute excess methane Termination of power supply in the affected area Emergency response plan in action Mine Rescue team on standby. Sealing of floor/ roof cracks after flushing off excess methane. All employees equipped with self contained self rescuer Use of ventilation ducts to flush accumulated roof 1. 2. 3. 4. 5. Consequence Asphyxiation due to lack of oxygen Small scale methane explosion due to spontaneous combustion of coal Coal seam fire Injury and possible fatality of workers Loss of Property 1. 2. 3. 4. 5. Asphyxiation due to lack of oxygen Methane explosion due to spontaneous Combustion of coal Coal seam fire Injury and possible fatality of workers Loss of property 1. Methane explosion due to spontaneous 1 Ritesh Kumar Mishra (600056904) - Minerals Resource Management Recovery Measure methane Emergency Response Plan in Action. 1. 1. 3. 3. Methane flooding leading to asphyxiation and explosion Rise in temperature of the mine Injury and possible fatality of workers Loss of property 1. 2. 4. 6. 5. 2. 3. 2. 2. 5 Drop in ventilation 3. 2. 4. 5. Consequence combustion Injury and possible death of workers Loss of property 1. 2. 7. 4. Employees equipped with self contained self rescuer 2. 2. 4. Use of emergency fan for ventilation Use of auxiliary fans to force air through needed areas House Nurse on duty Change in ventilation requirement from real time monitoring Employees equipped with self contained self rescuer Evacuation of mine workers Spare fan in place for sustaining ventilation Emergency response plan in action House Nurse on duty Mine rescue team on standby All employees equipped with self contained self rescuer Evacuation of Mine workers Spare equipment in place House Nurse on duty Emergency response plan in action Mine rescue team on standby All employees equipped with self contained self rescuer 1. 1. 3. 6 Ventilation Stall 3. 6. 4. 6. 3. 6. 3. 3. 4. 2. 4 Creation of negative pressure at coal seams 4. 5. 3. Rise in temperature in the mine Drop in oxygen levels Increased methane flow Possible Methane Explosion Injury and possible death of people Loss of property Drop in oxygen Methane built up Asphyxiation of workers Rise in mine temperature Possible Methane explosion Injury and possible death of workers Loss of property 2 Ritesh Kumar Mishra (600056904) . 4. 4. 1. 5. 4. 1. 1. 5. 5. 3. 2. Control Measures detectors Auxiliary ventilation to push air through areas of difficult reach Scaling of roofs to allow as laminar ventilation flow as possible Ventilation layout to suit entire cross section of working Airflow simulation studies Use of overcast against stoppings and airlock Training of Ventilation staff for best work practices Tandem airlocks which do not allow both doors to be open at same time Periodic Maintenance of fans Periodic maintenance of fans On-shift/pre shift examination to study blockages in ventilations networks Real time monitoring of airflow Auxiliary fans in place for additional ventilation requirements Use of two fans for push and pull to be used in case of failure of one Pre shift/on shift examination of working to inspect for blockages or roof collapse Periodic maintenance of Fans Preventative Maintenance system in place for main E x p l o s i o n i n t h e m i n e 2.CSMM101 – Hazard and risk management Bow tie method for risk assessment Hazard Threat the mine 2.Minerals Resource Management . 3. 5. 2. Stone dust barriers to contain explosion Evacuation of mine workers Emergency response plan in action House nurse on duty Mine rescue team on standby. 1. 2. 3. 5. 4. 3. 7. 1. 4. 4. 4. 3. 4. All employees equipped with self contained self rescuer 2. 9 Rise in temperature 3. 4. 5. Submersion of safety equipments Drop in ventilation Asphyxiation of workers due to drowning Rise in mine temperature Methane built up (less likely to explosion) Injury and possible death of workers Loss of property Coal dust explosion triggered by small scale methane explosion Opening of sealed mine workings leading to methane inrush Injury and possible death of people by blast Death of people by asphyxiation due to carbon monoxide Loss of property Rise in temperature leading to heat stroke/ nausea Ignition of methane/coal dust leading to explosion Injury and possible death of people Loss of property 3 Ritesh Kumar Mishra (600056904) . 2. 6. 7 Flooding of workings leading to obstructive ventilation 4. 3. House nurse on duty Mine rescue team on standby Emergency response plan in action 1. 2.CSMM101 – Hazard and risk management Bow tie method for risk assessment Hazard Threat 5. Flushing of air to control temperature/flush exhaust gases House nurse on duty Evacuation of mine workers. 5. 4. Recovery Measure Consequence E x p l o s i o n i n 1. Spare pumping equipment in place Evacuation of workers. Control Measures ventilation fans Auxiliary fan network to force air in required areas Series of pump installation at sumps to avoid flooding Sealing of old mine workings Proper roof /floor/pillar design to prevent inundation due to cracking Air flow simulation and real time monitoring Periodic gas measurements of sealed mine workings On shift/pre shift examination Intermixing of stone dust with the dust stream Use of high pressure water mist to reduce suspended coal dust Spraying of water on belt conveyors and tailgate to reduce suspended dust Ventilation design to flush out suspended dust particles Periodic inspection of faces prone to coal dust On shift/pre shift examination Rigorous checks to contain spontaneous combustion of exposed coal Ventilation air adequately cooled to provide proper working condition All diesel operated equipments to undergo checks to meet standards suitable to work in coal mine. 1. 3.Minerals Resource Management . 1. 6. 3. 3. 6. 2. 1. Emergency response plan in action 5. 2. 2. 5. 8 Large Suspension of float coal dust in entries t h e m i n e 2. 1. 3. 6. 1. 2. Construction of refuge chambers underground Periodic inspection of escape routes Use of alternate/multiple escape routes Escalation Factor Blockage of escape routes 4. 6. 1. 4. Explosion of methane/coal dust. 1. 4. 2. 2. 1. 1. 2. 3. Alternate arrangement of nurse on announced absence First aid training to employees Close contact with nearest hospital/clinic Unavailability of house nurse 1. 3. 2. 5. 2. Stone dust barriers to contain explosion Water nozzle to douse open flame Evacuation of workers House nurse on duty Emergency response plan in action Mine rescue team on standby All employees equipped with self contained self rescuer 1. 3. 4. 2 Malfunctioning of methane detectors 3. Control Measures Exhaust of equipments monitored to mitigate heat generation All equipment to meet explosion proof standards Strict adherence to ‘no smoking policy underground’ Shearers/cutters fitted with water nozzles to douse any ignition Maintenance of cutter bits to prevent spark generation due to blunt bits Methane monitors on cutting equipments Recovery Measure Consequence 1. 5. 5.Minerals Resource Management . Asphyxiation of workers Injury and possible death of people Damage to equipment Loss of property Escalation Factor 1. 1 Failure of coal drainage system 3. Drainage pipes maintained regularly Pressure of methane monitored in real time Preventative maintenance system in place for drainage network Drainage pipes of adequate factor of safety Periodic inspection Purchase of approved detectors Periodic examination of detectors Use of multiple detectors at interval Adequate training of employees in using detectors Purchase of fans of approved standards Periodic maintenance of fans 1. 5. 7. 3. 10 Generation of Spark 4. 3 Malfunctioning of Auxiliary fans 2. Rigorous training for emergency preparedness Mock drills for emergency preparedness Poor execution of Emergency response plan 4 Ritesh Kumar Mishra (600056904) . 2. 3.CSMM101 – Hazard and risk management Bow tie method for risk assessment Hazard Threat 4. 2. 5. 3.CSMM101 – Hazard and risk management Escalation Factor 3. 4. 2. 2. 2. Use of multiple pumps Preventative maintenance of pumps On shift/pre shift examination 1. Filtering of spray water Periodic checks of spray nozzles On shift/pre shift examination Employee selection based on job suitability Training and assessment of employees Supervision and feedback 1. 3. 1. 4 3. 7 Human error 2. 3. 1. 5 Ritesh Kumar Mishra (600056904) . 6 Clogging up of water nozzles 3. 5 Failure of pumps 3. Stone dusting rendered ineffective Periodic checks for faults in ventilation ducts Placement of ducts near roof to avoid damage Periodic monitoring of float dust and requirements of stone dust Bow tie method for risk assessment Escalation Factor 1. 2. 2. Periodic maintenance of self rescuers Checklist for equipment assessment before entering the mine Training in proper use of self rescuers Training by certified bodies (MSHA etc) Mock drills Periodic maintenance of safety equipments Multiple rescue teams to ensure availability Approved designed standard of dust barriers Periodic maintenance of dust barriers On shift/pre shift examination Malfunctioning of SCSR Poor execution by Mine Rescuers Ineffective stone dust barriers 1.Minerals Resource Management . 4. Carried out by panel foreman 2. Shortcoming recorded in shift book and informed to management over phone or the same day depending on severity 1. Equipment to be used once remedial measures in place 1. Shortcomings recorded in shift book 3. Training carried out by certified bodies 3. Checklist by operator before using the equipment 4. Communication to workers through rigorous training 3. Carried out by panel foreman 2. Arranged and scheduled by management 2.CSMM101 – Hazard and risk management Tasks Type of task On shift examination Bow tie method for risk assessment 1 2 Pre shift Examination 3 4 Preventative Maintenance plan of equipment Breakdown Maintenance 5 Safety checks for equipment Emergency Response Plan Training in best practices 6 7 8 Mine rescue training Responsibility distribution 1. Carried out by in house health and safety department or external trainers 3. Shortcomings noted in log book and reported to management 3. Carried out by the operator in a form every time before using the equipment 5. Mine workers report the shortcoming to panel foreman 3. Shortcomings reported to the management 6. Prepared by management 2.Minerals Resource Management . Safety equipment procured by management 4. Mock drill scheduled by management in co operation with panel foreman 1. Personnel selected by management in co operation with supervisors/foreman 2. Refresher training and assessment carried out by management 1. Equipment to be used once remedial measures in place 1. Prepared by Management in co operation with equipment operators 2. Maintenance of equipment as per the preventative maintenance and breakdown maintenance scheme 6 Ritesh Kumar Mishra (600056904) . Equipment to be used once completely repaired 3. Carried out by trained professionals 2. Workers allowed to enter the mine once the remedial measures have been taken 1.