Spontaneous Combustion Testing for Hazard Management Planning Dr B Basil Beamish MAusIMM CP (Min) RPEQ Technical Director CB3 Mine Services Pty Ltd 3/20 Archerfield Road, Darra Qld 4076 T: +61 7 33754100 M: +61 488 708 949 b.beamish@cb3mineservices.com International Conference and Exhibition on Occupational Health and Safety in Mines Istanbul December 2014 Presentation outline • The Sponcom process and requirements for a Principal Hazard Management Plan • Assessment of self-heating propensity in Australia • Examples of spontaneous combustion testing results and interpretation for mine planning • Conclusions International Conference and Exhibition on Occupational Health and Safety in Mines Istanbul December 2014 Sponcom process (Moreby and Chalmers, 2006) Coal + O2 CO, CO2, and H2O + HEAT Intrinsic and extrinsic factors determine reaction rate INCREASES REACTION RATE INCREASES COAL TEMPERATURE RETAINED Incubation period is the time taken for coal to reach thermal runaway with given intrinsic and extrinsic factors. LOST Balance determines development of event CONVECTION CONDUCTION EVAPORATION • • • • • Oxidation rate doubles for each 10⁰C rise in temperature, once the coal temperature exceeds 70⁰C Coal is a good insulator and can retain heat for years Coal can retain elevated activity for years Incubation periods can range from weeks to years Never use incubation period to International avoid controls Conference and Exhibition on Occupational Health and Safety in Mines Istanbul December 2014 MDG1006 Spontaneous Combustion Management Guideline • Updated by the NSW Mine Safety Operations Branch in February, 2011 released in May 2011 • www.resourcesandenergy.nsw.gov.au/__data/assets/pdf _file/0007/419515/MDG-1006.pdf • The intent of this guideline is to provide assistance to mines in the development and implementation of a Principal Hazard Management Plan (PHMP) for Spontaneous Combustion. • Spontaneous combustion testing information is required to assess propensity to self-heat and to obtain data on gas evolution associated with coal temperature increase. International Conference and Exhibition on Occupational Health and Safety in Mines Istanbul December 2014 Common Sponcom tests used by the Australian Coal Mining Industry • • • • Common tests measure the intrinsic spontaneous combustion propensity under set conditions with no indication of time to thermal runaway. Assessment is based on a rating scheme compared against previous coal histories. Crossing Point Temperature (CPT) and Relative Ignition Temperature (RIT) are high temperature index tests and do not provide any measure of the coal self-heating at low ambient temperature. They are also measured by force heating the coal in an oven. Minimum Self-heating Temperature (SHT) and R70 self-heating rate are low temperature index tests and provide a measure of the coal self-heating at low ambient temperature. They are measured in an adiabatic oven that allows the coal to heat itself, although SHT is now calculated from the oxygen content of the coal. New SponComSIM™ testing provides additional data on the time taken to reach thermal runaway using site boundary conditions and is benchmarked against coals with known self-heating performance. International Conference and Exhibition on Occupational Health and Safety in Mines Istanbul December 2014 Sampling strategies for Sponcom assessment of a longwall mine • Site specific and tailored to suit project objectives • Top, middle and bottom of seam, plus any rider seams likely to fall into the goaf or floor coal left behind • Minimum 800g required per sample (25cm of HQ core) • Longwall operations tested every longwall panel • Fresh face lumps just as good as core • R70 testing of all samples for assessing intrinsic spontaneous combustion propensity • SponComSIM™ testing of specific samples for benchmarking thermal runaway timeframe • SponComGAS™ testing for evaluating gas evolution trends in support of TARPs International Conference and Exhibition on Occupational Health and Safety in Mines Istanbul December 2014 Example of repeat R70 testing for a Newcastle high volatile bituminous coal 160 Temperature (oC) 140 120 100 R70 = 4.90 oC/h 80 R70 = 4.73 oC/h 60 40 20 0 1 2 3 4 5 6 Time (hours) LAB A (Oven 1) LAB A (Oven 1) International Conference and Exhibition on Occupational Health and Safety in Mines Istanbul December 2014 7 8 9 10 Example of repeat R70 testing for an Australian sub-bituminous coal 160 Temperature (oC) 140 120 100 R70 = 34.27 oC/h 80 R70 = 33.42 oC/h 60 40 20 0.0 0.5 1.0 Time (hours) LAB A (Oven 1) LAB A (Oven 1) International Conference and Exhibition on Occupational Health and Safety in Mines Istanbul December 2014 1.5 2.0 Intrinsic Spontaneous Combustion Propensity classification (ISCP) based on Qld and NSW coal conditions (Beamish and Beamish, 2012) Queensland New South Wales ISCP Class Propensity rating R70 value (°C/h) R70 value (°C/h) I low (L) R70 < 0.5 R70 < 1 II low-medium (LM) 0.5 R70 < 1 1 R70 < 2 III medium (M) 1 R70 < 2 2 R70 < 4 IV high (H) 2 R70 < 4 4 R70 < 8 V very high (VH) 4 R70 < 8 8 R70 < 16 VI ultra high (UH) 8 R70 < 16 16 R70 < 32 VII extremely high (EH) R70 16 R70 32 International Conference and Exhibition on Occupational Health and Safety in Mines Istanbul December 2014 New South Wales intrinsic spontaneous combustion propensity plot 8 7 High R70 (oC/h, db) 6 5 4 3 Medium 2 Low - Medium 1 Low 0 0 5 10 15 20 25 30 35 Ash content (%, db) Illawarra 1 Illawarra 2 Hunter Valley Upper Hunter Newcastle Western San Juan Spring Creek International Conference and Exhibition on Occupational Health and Safety in Mines Istanbul December 2014 40 45 50 Examples of SponComSIM™ testing to establish time to thermal runaway 160 40-60 days 10-15 days Temperature (oC) 140 120 100 80 60 40 20 0 10 20 30 40 50 60 70 80 90 100 Time (hours) Kideco Newcastle A Spring Creek LW3A Illawarra (Bulli) LW3B International Conference and Exhibition on Occupational Health and Safety in Mines Istanbul December 2014 110 120 Example of recent Queensland case study 160 120 100 67-100 days 40-60 days 10-15 days Temperature (oC) 140 80 60 40 20 0 10 20 30 40 50 60 70 80 90 100 110 120 Time (hours) Kideco Spring Creek K4E Low Ash (35C) International Conference and Exhibition on Occupational Health and Safety in Mines Istanbul December 2014 K4E Low Ash (40C) 130 140 Quantification of reactive pyrite effect 160 RIT = 149 oC Temperature (oC) 140 120 100 80 R70 = 1.73 oC/h 60 40 20 0 2 4 6 8 10 12 14 16 18 Time (hours) R70 SponComSIM International Conference and Exhibition on Occupational Health and Safety in Mines Istanbul December 2014 20 22 24 26 28 30 Effect of increasing amounts of reactive pyrite (Beamish, Lin and Beamish, 2012) 160 40-60 days 10-15 days Temperature (oC) 140 120 100 80 60 40 20 0 10 20 30 40 50 60 70 80 Time (hours) Kideco Spring Creek BBHVB03 BBHVB06 International Conference and Exhibition on Occupational Health and Safety in Mines Istanbul December 2014 BBHVB13 BBHVB01 90 Trigger Action Response Plan (TARP) setting for underground mines • Identification of most appropriate indicator gases and ratios – Initially based on gas evolution testing of the coal – TARP trigger levels set at logically determined values that are site specific (internal standard) – Refined as part of the review process with mine site experience – Possibility of differing geological domains influencing TARP trigger levels International Conference and Exhibition on Occupational Health and Safety in Mines Istanbul December 2014 Small-scale gas evolution testing • Characterises the gas evolution trend that occurs in response to coal self-heating as the temperature of the coal increases • Results are evaluated for the specific trends of individual gases and gas ratios • The information can be used to identify key indicator gases and ratios for use in TARPs and to support the alarm limits set in the TARP • Coal is step heated up to approximately 180°C and gases analysed by GC include: O2, N2, CH4, CO2, CO, H2, C2H6, C2H4 International Conference and Exhibition on Occupational Health and Safety in Mines Istanbul December 2014 0.020 4 0.015 3 0.010 2 0.005 1 0.000 0 40 Hydrogen 60 80 Ethylene 100 Ethane 120 140 160 Temperature (°C) Methane Carbon Monoxide International Conference and Exhibition on Occupational Health and Safety in Mines Istanbul December 2014 180 200 Carbon Dioxide Carbon Monoxide, Carbon Dioxide (%) Hydrogen, Ethylene, Ethane, Methane (%) Individual gas evolution results for Area A of a New South Wales mine 0.020 4 0.015 3 0.010 2 0.005 1 0.000 0 40 Hydrogen 60 80 Ethylene 100 Ethane 120 140 160 Temperature (°C) Methane Carbon Monoxide International Conference and Exhibition on Occupational Health and Safety in Mines Istanbul December 2014 180 200 Carbon Dioxide Carbon Monoxide, Carbon Dioxide (%) Hydrogen, Ethylene, Ethane, Methane (%) Individual gas evolution results for Area B of a New South Wales mine Graham’s ratio trend with increasing coal temperature for Area A 5.5 5.0 4.5 Graham's Ratio (%) 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 Measured GR Extrapolated GR 0.0 20 40 60 80 100 120 140 Temperature (°C) International Conference and Exhibition on Occupational Health and Safety in Mines Istanbul December 2014 160 180 200 Conclusions • Reliable and accurate results with appropriate interpretation are required by industry for Spontaneous Combustion Principal Hazard Management Planning. • Relevant laboratory spontaneous combustion testing is required to evaluate the risk of developing an event under the site specific conditions of each mine and within different areas of the mine. • Gas evolution testing provides support for the selection of appropriate indicator gases and ratios used in TARPs. International Conference and Exhibition on Occupational Health and Safety in Mines Istanbul December 2014 References • Beamish, B and Beamish, R, 2012. Testing and sampling requirements for input to spontaneous combustion risk assessment, in Proceedings of the Australian Mine Ventilation Conference, B Beamish and D Chalmers (eds), pp 15-21 (The Australasian Institute of Mining and Metallurgy: Melbourne). • Beamish, B, Lin, Z and Beamish, R, 2012. Investigating the influence of reactive pyrite on coal self-heating, in Proceedings 12th Coal Operators’ Conference, N Aziz (ed), pp 295-300 (University of Wollongong and The Australasian Institute of Mining and Metallurgy). • Moreby, R and Chalmers, D, 2006. Mine ventilation course notes, Mining Education Australia. International Conference and Exhibition on Occupational Health and Safety in Mines Istanbul December 2014 Questions? International Conference and Exhibition on Occupational Health and Safety in Mines Istanbul December 2014