ABSTRACT
Gas and rook outbursts are the most dangerous hazard for miners in Lower Silesian Coal Basin. The mining safety requires accurate knowledge of the rook stresses formation and their changes related to mining operations. Our intention was to determine the stress distribution inside coal seam. To satisfy these requirements the seismic method, based on the relationship between rock stresses and seismic waves velocities, was chosen. By periodically repeating measurements in the same area, it was possible to observe the changes of the stresses caused fey various factors. Tomographic imaging techniques were applied to determine the velocity distribution. High and low velocity zones were recovered. It was confirmed that the great care was necessary in application such techniques to avoid possibility of poor reconstruction.
