Mapping of old coal mine galleries near railway track using electrical resistivity tomography and magnetic approaches in Tundu, Jogidih Colliery, Jharia Coalfield, India.

Underground galleries possess random subsidence threats if they are not treated well. Threats even become multifold when these galleries are located somewhere in the vicinity of the railway tracks. So, checking the stable ground formation or the health of the subsurface formation near railway tracks and mapping the galleries are very important tasks for the sake of the environment, economy and lives. Galleries under the present study are associated with the coal seam-X and seam-XA of the Jogidih Colliery of Jharia Coalfield. Seven electrical resistivity tomography (ERT) profiles and magnetic surveys were performed at a side of the railway track to characterize the subsurface formation near railway tracks and to detect the gallery and its extension. Both ERT and magnetic data analysis suggest the presence of some galleries at a certain distance from the railway tracks. Moreover, combined analysis of ERT and magnetic data suggests that ground within ~20 m from the railway tracks is found to be stable with homogeneous compact formation. [ABSTRACT FROM AUTHOR]