Investigations on methane emission from flooded workings of closed coal mines

The migration of methane towards the surface, within mining areas of closed mines, can be a danger to public safety for many of years after the process of liquidation has been finished. The liberation of methane from undisturbed coal seams, and those destressed through earlier mining has not been fully recognised so far. Knowledge of the effect of the presence of water, along with hydrostatic pressure, on the intensity of methane desorption from destressed seams is necessary in determining the approximate volume of methane inflowing, within a period of time, into a closed mine. Laboratory tests on these relationships have been carried out in accordance with proper research methodology by the National Institute for the Environment and Industrial Hazards (INERIS), France with the Central Mining Institute, Katowice, Poland. The results have facilitated determining the effect of hydrostatic pressure variation of water on the intensity of methane desorption from flooded coal. These results has been practically applied in predicting the emission of methane into closed mines, and in orienting the rules of methane hazard control, both during the process of mine closure, and on the surface of post-mining areas.