GABRIELA LOCALITY: STARTING GEODETIC OBSERVATIONS TO DETECT THE SURFACE MANIFESTATIONS FROM UNDERMINING
A new observation network has been built to observe the surface manifestations of undermining at Gabriela locality. This locality lies in the Czech part of the Upper Silesian Coal Basin and the history of the hard coal underground exploitation is more than 150 years long here. Recently, the last coal mining panel was started to be exploited here. Its location and mining parameters are very suitable for the analysis of the actual and future surface changes caused by undermining. The fixed points of the observation network are surveyed by geodetic GNSS method. This method enables the evaluation of both vertical subsidence and horizontal displacements. Such complex evaluation of processes on the surface of the undermined territory makes it possible to understand the progress of the subsidence depression and to capture the final phase of the surface undermining changes, i.e. the phase of the subsidence decline.