Electrometric studies in Krylatovskii mine
Research aims to show the possibility of studying the processes occurring after underground workings flooding by electromagnetic methods of geophysics by the example of Krylatovskii mine. After mine closure underground workings were completelyflooded and caved in. An important task is to assess the risk of new surface subsidence formation. Research methodology. Electromagnetic surveys included vertical electrical soundings (VES), an express version of audio magnetotelluric soundings (AMTS), and remote induction soundings (RIS) with a vertical magnetic dipole. Electrometry tasks included the determination of loose sediments nature, rocks integrity, and weakened zones presence. AMTS and RIS works were carried out with the sets of electrical survey equipment OMAR-2m (ОМАР-2м) andMFS-8 (МЧЗ-8). VES works were carried out with LFE-3 (АНЧ-3) equipment. VES, AMTS and RIS quantitative interpretation included the realization of consistent geoelectrical sections with calculated layer depths and electrical resistance values. These compositions make it possible to determine the nature of changes in the electrical properties of the section and identify local anomalous objects. Results. According to the results of processing, quantitative and qualitative sections of the electrophysical parameters of the medium were constructed, allowing to determine the nature of changes in the properties of the section and identify local anomalous objects. The performed work showed sharp changes of resistivity in the upper part of the section, associated with heterogeneous composition of technogenic bulk soils on the territory of Krylatovskii mine. The obtained geoelectrical sections reliably distinguish the position of low resistance anomalies. The results of different geophysical methods agree well with each other. Conclusions. An extensive area of increased electrical conductivity with depth up to 130 m and width about 50 m has been revealed. It may be a flooded weakened zone of increasedfracturing, prone to further destruction. This indicates potential danger of displacement processes in area of submerged underground workings with formation of new subsidence of the earth’s surface.