Comprehensive geophysical exploration of closed hidden danger mined-out areas under mines

Based on the previous transient electromagnetic method （TEM） detection and according to the occurrence location of detected target areas, TRT geological advanced prediction technology was further adopted for comparative detection and analysis to know about the possible occurrence of cavities and loose body boundaries in the hidden danger mining areas under the Tongkeng Mine. The mining technical conditions in the closed hidden danger mining areas were grasped from the perspective of time and space. The results show that for survey line 1, the TEM detection results suggest that there may be large interstices at the early stage, and the TRT detection results show that the goaf features are not significant. It is possible that the goaf is further filled due to the continuous caving and falling of loose bodies. For survey line 2, the state of rock mass structure （loose body accumulation） in region B basically remains unchanged, suggesting a stable state. The feasibility of the comprehensive detection method in the exploration of concealed cavity detection and hidden danger investigation was verified, thus providing technical support for the safe and efficient recovery of complex and hard-to-mine resources in mines.