HYDROGEOLOGICAL RESEARCH METHODS AS A TOOL FOR ASSESSMENT OF THE FREE SPACE CAPACITY IN ROCK MASS, GOAFS AND MINING EXCAVATIONS IN COAL MINES IN UPPER SILESIAN COAL BASIN.

Mining exploitation in an underground mine is the main factor disturbing the balance within the rock mass. By removing the obtained raw material from the rock mass mining activity leads to changes in the broadly understood state of the natural environment. Extraction of the raw material - hard coal with barren rocks is often associated with the need to undertake dewatering of the rock mass and discharging mine gases into the atmosphere. The process of extracting the raw material from the deposit and the accompanying water and gases leads to changes in the physical and mechanical properties of the rock mass, creating secondary empty spaces in it that can conduct and accumulate waters and mine gases, especially in conditions of active and liquidated mines. The hydrogeological properties of the rock debris are largely dependent on the geomechanical conditions present in the rock mass surrounding the coal seams. Therefore, based on the example of the USCB geological environment, authors present selected hydrogeological research methods recommended for estimating the free space capacity as well as for the assessment of conditions for the accumulation of gases and water in mining excavations, goafs and rock mass. In addition, the possibilities of the results of such tests in forecasting the water and gas capacity of the free spaces in the underground mine were indicated. Attention was paid to the possibility of their use in the assessment of possible natural hazards and for the management of water and methane in abandoned mines. [ABSTRACT FROM AUTHOR]