The intrusion of magmatic rocks into coal seams affects the coal quality and leads to unforeseen hazards in safety of the coal mines’ production. This paper summarizes the mechanism of magmatic rocks intruding into coal seams, depicts the electromagnetic characteristics of the coal seams intruded by magmatic rocks, briefly describes the characteristics of transient electromagnetic method (TEM), and introduces the method of detection by TEM and the data processing steps. Then, the effectiveness of TEM in detecting the ranges of the coal seams intruded by magmatic rocks is theoretically analysed. It is observed that after the intrusion of magmatic rocks in the coal seams, the electromagnetic characteristics (secondary field potential and resistivity) will be dramatically affected, namely high secondary field potential and low resistivity. For experimental verification purposes, this study selects the test project of the Tongxin Minefield in the Datong Coalfield in Shanxi, China as an example, and the accuracy for the detection of the ranges of the coal seams intruded by magmatic rock using TEM is successfully verified.

Ground penetrating radar (GPR) is an effective method that can be applied in pipeline leakage detection. However, when the distribution of the underground medium is complex, it becomes difficult to accurately identify the abnormal leakage area directly from the GPR data profile. In this paper, based on the characteristics of high water content in the abnormal leakage area and according to the relationship between the reflected wave coefficient and the dielectric constant, the electric field component imaging technology of GPR data is proposed. Next, the electromagnetic wave responses of geological models with different dielectric parameters are simulated by finite difference time domain (FDTD). It can be seen from the forward modeling results that the greater the difference is in the dielectric constants of the media on both sides of the interface, the stronger the reflected wave energy will be. Finally, the electric field component imaging technology of GPR data is applied to pipeline leakage detection in an industrial area. The test results show that the abnormal area of pipeline leakage appears as a high‐amplitude area in the electric field component map.

When magmatic rock intrudes a coal seam, it destroys the coal seam’s structure, reduces the coal quality, and brings hidden dangers to the safe production processes of the coal mine. In this study, the mechanism of magmatic rock intrusion into coal seams was briefly described. In addition, the changes in the structure, composition, and geophysics characteristics of the coal seams following the intrusion of magmatic rock were summarized. This study also performed a forward modeling was performed. Then, the effectiveness of the seismic attributes in detecting the ranges of the coal seams intruded by magmatic rocks was theoretically analyzed. It was observed that after the intrusion of magmatic rocks in the coal seams, the seismic attributes were dramatically affected. For example, the frequency band width values increased, central frequency values decreased, and the main amplitude values decreased. For experimental verification purposes, this study selected the test project of the Yuandian coal mine in the Huaibei area of Anhui, China as an example. The accuracy levels for the detection of the ranges of the coal seams intruded by magmatic rock with seismic attributes were successfully verified.

Adequate knowledge of velocity is required for accurate data imaging and depth conversion, as well as for quantifying the distribution of soil water content. Without complementary borehole information in the form of dielectric permittivity and/or porosity logs along the profile, it is currently impossible to reliably estimate the high-frequency electromagnetic velocity distribution in the probed subsurface region. Here, we present a new method for calculating the precise subsurface velocity structure from ground penetrating radar (GPR) reflection data that does not require boreholes or log data. This study investigates the ability of the pulse_EKKO PRO GPR system to predict a vertical profile for the possible velocity estimation of a layered and contaminated geophysical test site in Hangzhou, China. All data were acquired and saved on the GPR system in various files (projects) before analysis using GPR software to obtain approximated velocity modelling using common midpoint (CMP) gathers. Using the velocity spectrum analysis, a vertical profile of the interval velocities can be derived from each CMP gather. The findings of this study indicate that the proposed method is effective and sustainable. Furthermore, owing to the efficacy of the method in terms of field effort and computational complexity, it can easily be expanded to 3D GPR velocity exploration, increasing its importance in comparison to standard offset-based techniques for estimating velocity using GPR.