Experiences from Microgravity Method Application in Abandoned Coal Mine Sites - Two Examples from Austria and Slovakia

Abstract

Summary Geophysical detection and monitoring of subsurface cavities and subsidence effects over sites with mining activities is an very important task of near surface geophysics. Microgravity method can play an important role in the frame of such kind of research and monitoring. In our contribution we bring several examples (residual Bouguer anomalies interpretation) from the application of microgravity method together with other geophysical methods in sites with abandoned mining activities (brown coal mines in southern Austria and central Slovakia). Microgravity research was able to detect important negative anomalies in both cases – the first one was connected with a real migrating mining cavity, the second was probably an old surface collapse filled by debris and mining waste (both objects have been verified by in-situ drilling). Application of other shallow geophysical methods (electro-magnetic induction, electrical resistivity tomography and shallow refraction seismic survey) in the second case helped us to interpret the received microgravity anomaly in a more correct way.