Testing Device for Radon Migration Experiments, the Construction and Preliminary Results

The main goal of the research presented was to design and construct a device, enables estimation of the diffusion time and diffusion length for radon in core samples collected from the geological layers of Upper Silesian Coal Basin (USCB). Another goal will be investigations of the advection of 222Rn with other gases like carbon dioxide or methane, occurring in the Carboniferous strata in USCB. This knowledge will support the precision of the assessment of radon hazard in working environment. Moreover, it should give an answer to some questions, related to the radon migration issues—if the results of measurements of the transport of radon with other gases in the strata could be applied for the prediction of geodynamic phenomena in the mining areas, like tremors and outbursts. The study was focused on the flow measurements of the following gases: radon, carbon dioxide, nitrogen and their mixtures, as the use of methane was excluded due to potential hazard of explosion. In this article results of measurements of diffusive migration are presented: radon itself and simultaneous migration of radon, nitrogen and carbon dioxide. For this purpose a special device was designed and constructed. This device consists of the container for the sample of coal, mineral or rock and two reservoirs—the inlet and outlet one. The gas (e.g. air or carbon dioxide) with radon is introduced into inlet reservoir, while the content of marker gases and radon is monitored in the outlet reservoir. The preliminary experiments were also performed and are presented in this paper. In the literature, there are only rare results of such investigations, while our previous research in USCB region showed some correlation between sudden changes of radon level and geodynamic events. Therefore, the results of the investigations presented in this study are expected to contribute to the improvement of the models of these phenomena. The future work planned will be aimed at investigations of advective flow of radon with various carrier gases.