Williams, B, Donaldson, K & Beamish, B 2019, 'Risk profiling and control of spontaneous combustion for coal mine closure', in AB Fourie & M Tibbett (eds), Mine Closure 2019: Proceedings of the 13th International Conference on Mine Closure
, Australian Centre for Geomechanics, Perth, pp. 563-576, https://doi.org/10.36487/ACG_rep/1915_46_Williams
The Leigh Creek Coal Mine, located approximately 550 km north of Adelaide in South Australia, operated between 1944 and 2015.
The coal, being a low rank sub-bituminous coal, is prone to self-heating and localised spontaneous combustion. Throughout the many decades of mining operation a significant body of knowledge was generated regarding the causal factors and more effective treatment strategies for spontaneous combustion. These strategies were effectively suited to an operational mine site, but not specifically designed, nor tested, for closure.
A swift decision to close in June 2015, followed by a short mining operations shutdown period, presented significant operational, technical and regulatory challenges. The subsequent joint risk mapping process employed by Flinders Power and South Australian Mining Regulators was a unique example of obtaining realtime objective evidence through leading-edge science in order to inform the risk profile, determine the appropriate risk management strategies for closure and develop an appropriate mine closure plan.
In developing the risk assessment for closure, the following three key assumptions needed to be tested.
These assumptions were founded on operational experience and expert advice, however applicability to a rehabilitation phase had not been validated for the site.
To address these uncertainties extensive laboratory test work and a unique field trial installation on an area of active combustion was conducted. The testing of these assumptions formed the basis of the rehabilitation specification, area-specific rehabilitation designs and subsequent completion criteria. The use of a risk and evidentiary-based approach to categorise spontaneous combustion hazard likelihood for developing an appropriate rehabilitation design across the vast 70 km2 open cut coal mine forms the basis for this paper.
Keywords: open cut coal mine rehabilitation, spontaneous combustion, closure risk management
Arisoy, A, Beamish, B & Cetegen, E 2006, ‘Modelling spontaneous combustion of coal’, Turkish Journal of Engineering and Environmental Science, vol. 30(2006), pp. 193‒201.
Beamish, B 2014, Review of spontaneous combustion management at Leigh Creek Coal Mine, B3 Mining Services Technical Report -2014/TR001.
Beamish, B & Beamish, R 2011, ‘Testing and sampling requirements for input to spontaneous combustion risk assessment’, in B Beamish & D Chalmers (eds), Proceedings of the Australian Mine Ventilation Conference, The Australasian Institute of Mining and Metallurgy, Melbourne, pp. 15–21.
Beamish, B, Barakat, MA & St George, JD 2000, ‘Adiabatic testing procedures for determining the self-heating propensity of coal and sample ageing effects’, Thermochimica Acta, vol. 362, no. 1–2, pp. 79–87.
Beamish, B, Theiler, J & Garvie, A 2019, ‘Ageing effect on the self-heating incubation behaviour of lignite’, in N Aziz & B Kininmonth (eds), Proceedings of the Coal Operators’ Conference, The University of Wollongong, Wollongong,
Cliff, D, Brady, D & Wilkinson, M 2014, ‘Developments in the management of spontaneous combustion in Australian underground coal mines’, Proceedings of the 14th Coal Operators Conference, The Australasian Institute of Mining and Metallurgy, Melbourne, pp. 330‒338.
Dames & Moore Pty Ltd 1984, Leigh Creek Coalfield: Lobe B, Geotechnical and Hydrogeological Investigations, Phase 1, Groundwater and Dewatering, October 1984.
Day, S 2008, Spontaneous Combustion in Open Cut Coal Mines, Final Report for ACARP Project C17006,
Eroglu, N & Moolman, C 2003, Develop methods to prevent and control spontaneous combustion associated with mining and subsidence, Coaltech 2020 Project 3.4.1,
Flinders Power 2018, Approved Mine Closure Plan,
Garvie, A, Donaldson, K, Williams, B & Chapman, J 2019, ‘A demonstration of the cessation of spontaneous combustion in a coal overburden spoil pile’, in AB Fourie & M Tibbett (eds), Proceedings of the 13th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 897–910.
Jones, P & Franklin, C 2019, ‘Relinquishment criteria verification: quality assurance/quality control using unmanned aerial vehicles,’ in AB Fourie & M Tibbett (eds), Proceedings of the 13th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 1461–1476.
Parkin, L 1953, The Leigh Creek Coalfield, Bulletin No 31, South Australia Department of Mines, Geological Survey, KM Stevenson, Government Printer, Adelaide.
Phillips, H, Uludag, S & Chabedi, K 2011, Prevention and Control of Spontaneous Combustion Best Practice Guidelines for Surface Coal Mines in South Africa, Coaltech Research Association.
Salmon, D 2017, Guidelines for Coal Mine Open Pit Final Void Closure and Relinquishment – Addressing Uncertainty in Coal Mine Environmental Planning, ACARP Project 25030, published 01/06/2017.
Williams, B & Querzoli, A 2018, ‘Risk management for minesite closure planning and execution – start now! Lessons from the closure of the Leigh Creek Coalfield, South Australia,’ Proceedings of Life-of-Mine 2018, The Australasian Institute of Mining and Metallurgy, Melbourne, pp. 68–72.