Radon in the investigations of geo-hazards in Polish collieries

摘要

Outbursts (releases of gas and coal from exposed coal face) are dangerous events in coal mines, potentially lead-ning to damage in the galleries and casualties among miners. For that reason, monitoring of this hazard is verynimportant in collieries with seams prone to outbursts. Current hazard indicators are not sufficient for the propernprediction of geodynamic events and any effort to find a new and better method of monitoring is thus desirable.nDuring the 1980s and 1990s, attempts were undertaken to apply specific radiometric methods to support thenprediction of outbursts in collieries in the Lower Silesian Coal Basin (LSCB) in south-western Poland. This idea wasndeveloped as an analogy to the study of radon changes in groundwater prior to earthquakes. This study investi-ngates the hypothesis of possible variations of radon emanation from coal seams prior to outbursts. Techniquesnand a methodology of radon observation in gas samples from strata were developed and applied. It has been sta-nted that there is a degree of correlation between the temporal and spatial variations of radon level and the haz-nard level of an outburst. In the 1990s, all collieries in LSCB were abandoned and further investigations were thusnstopped. In the last few years, the occurrences of outbursts were noticed in the collieries of Upper Silesian CoalnBasin. For that reason, we initiated the monitoring of radon concentration as sampled from headings in danger-nous coal seams. The purpose of the research is an attempt to introduce a new parameter, ‘the radon indicator ofnoutburst hazard’, which could be used to support other routinely applied techniques of outburst prediction. Thisnstudy provides some results from previous investigations performed in the collieries of the LSCB, as backgroundnand calibration to the preliminary results of the new research, performed in one of the coal mines in Upper Silesianregion.