DOI https://doi.org/10.36487/ACG_repo/2415_87
Cite As:
Lafortune, S, Herbout, A, Lefebvre, O, Arnone, T, Tardivon, J & Bigarré, P 2024, 'Risk management related to long-term mine gas emissions: feedback from a French experience', in AB Fourie, M Tibbett & G Boggs (eds),
Mine Closure 2024: Proceedings of the 17th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 1209-1220,
https://doi.org/10.36487/ACG_repo/2415_87
Abstract:
Mine closure activities in underground mines lead to stopping water pumping and ventilation systems. Unflooded voids form reservoirs where dangerous air or toxic gas can appear. Adits, shafts or boreholes shape potential migration pathways for gas transfer to the surface but also fresh air entrances. Gas can also migrate through overburden if it is fractured by former underground mining activities. Eventually gas migration between mining voids and the surface is mostly driven by temperature and pressure gradients that cyclically change with seasons.
Gases constituting the atmospheres within underground old mines have several possible origins: surface ‘fresh’ air entrance, degassing from rock formations (e.g. coal seams), deep gas seepage (e.g. mantle gas), redox or acid-base reactions, biological processes, etc. Any underground mining context may be affected by risks related to mine gas. Usual components of mine gas are nitrogen, oxygen, carbon dioxide, methane, carbon monoxide and hydrogen sulphide.
Once emitted to the surface, mine gas may lead to hazardous situations for people. Related hazards are explosion, suffocation and poisoning. Underground mine gas reserves, migration pathways, the composition of the emitted gas, the dynamics of the emission (flow, duration) and the potential of accumulation in dwellings, confined or semi-confined premises (i.e. poorly ventilated spaces such as cellars, basements, underground networks and inspection hatches) must be considered when managing the risks.
In two case studies of populated areas we illustrate how risks related to mine gas emissions to the surface are managed in France: the first in a former coal basin and the second in a former iron ore mining area.
Authors detail how mine gas monitoring helps to understand underground gas production processes and gas migration transfers to the surface. They also describe mitigation measures implemented and provide feedback based on French experiences.
Keywords: mine gas, emission, surface, monitoring, risk management, mitigation, France
References:
Banks, D, Younger, PL, Arneses, RT, Iversen, ER & Banks, SB 1997, ‘Mine-water chemistry: the good, the bad and the ugly’, Environmental Geology, vol. 32, no. 3, pp. 157–174,
GEODERIS 2020, Emissions de Gaz de Mine (Mine Gas Emissions), viewed 31 May 2024,
Ineris 2016, Évaluation de l’aléa "Gaz de Mine" : Guide Méthodologique (Assessment of the “Mine Gas” Hazard: Methodological Guide), viewed 31 May 2024,
Lafortune, S, Gouzy, A & Vuidart, I 2023, 'Forecast and mitigation of the pressure build-up in a depleted mine gas reservoir: case study in a French coal basin', in B Abbasi, J Parshley, A Fourie & M Tibbett (eds), Mine Closure 2023: Proceedings of the 16th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth,
Lafortune, S, Pokryszka, Z & Charmoille, A 2019, ‘Underground gas production and migration induced by mining subsidence’, in Proceedings of 14th International Congress of Rock Mechanics and Rocks Engineering, International Society for Soil Mechanics and Geotechnical Engineering, London,
Lagny, C 2014, ‘The emissions of gases from abandoned mines: role of atmospheric pressure changes and air temperature on the surface’, Environmental Earth Sciences, vol. 71, no. 2, pp. 923–929,
Lagny, C 2015, ‘Noxious gas emissions above former coal and iron mines in Lorraine due to the presence of iron sulphides’, Environmental Earth Sciences, vol. 74, no. 7, pp. 6303–6313,
Mayo, AL, Petersen, EC & Kravits, C 2000, ‘Chemical evolution of coal mine drainage in a non-acid producing environment, Wasatch Plateau, Utah, USA’, Journal of Hydrology, vol. 236, no. 1-2, pp. 1–16,
Pokryszka, Z & Grabowski, D 2003, ‘On the surface noxious gas emissions from old iron mines’, in Proceedings of the 30th International Conference of Safety in Mines Research Institutes, The South African Institute of Mining and Metallurgy, Johannesburg,
Vuidart, I, Hadadou, R, Hanocq, P & Semmelbeck, L 2014, ‘Post-mining management in a major French mining area – example of the Lorraine iron ore basin’, Mine Closure 2014: Proceedings of the 9th International Conference on Mine Closure, The University of the Witwatersrand, Johannesburg,