Imaging of Karst Features to Guide Mining Activities in a Marble Quarry by Means of 3D ERT
S.S. Uhlemann, J.E. Chambers, A. Tirado Alonso, A. Espín de Gea and W.E. Falck
Event name: Near Surface Geoscience 2015 - 21st European Meeting of Environmental and Engineering Geophysics
Session: Soil & Rock Characterization III
Publication date: 06 September 2015
Info: Extended abstract, PDF ( 2.46Mb )
Price: € 20
This study shows the application of 3D Electrical Resistivity Tomography (ERT) to the characterization of a narrow and deep open-pit marble quarry, in order to develop near-surface geophysical methods as an aid to realize the concept of an invisible, low-impact quarry. The purpose of the survey was to prove the applicability of ERT to image the extent and shape of subvertical faults and cavities in a highly resistive hard rock environment, thus allowing for targeted extraction of the natural stone reserve and a reduction of mining waste. ERT faces a range of challenges when applied to a hard rock environment, namely very high contact resistances, preferential current flow through conductive surface layers, and pronounced topographic features, which have to be accounted for in the data inversion. Despite these challenges, results show that using 3D ERT it was possible to outline the extent of a cave below the lower quarry floor and to identify the location of the fault causing the karstification. Observations recorded during data acquisition correlated well with the features imaged in the 3D ERT surveys, indicating the reliability of the results.