Application of magnetotelluric method to the detection of overburden failure height in shallow seam mining

This paper studies the reliability of magnetotelluric (MT) method detection for overburden failure (OF) height in shallow seam mining. According to the geological conditions of the 52,505 working face in the Daliuta mine, five observation lines have been designed to detect the apparent resistivity (AR) of the overburden before and after mining. Analyzed the characteristic points of the face and the AR of the overburden on the main section and studied the characteristics of AR for various overburden lithologies. The AR of the overlying strata corresponding to different failure conditions is also different. Further obtained the height of the caved zone (CZ) on the working face was 25.6 m, and the height of the water flowing fracture zone (WFFZ) was 82.5 m. Finally adopted the numerical simulation and an empirical formula for calculation to validate the MT detection results and proved that it was reliable to use the MT method to detect OF height, thus providing a convenient, fast, economical, and reliable method for detecting OF heights when mining in shallow seams.