Researchers have explored the electromagnetic response characteristics of water-rich zones in mines, focusing on integrating transient electromagnetic (TEM) and direct-current (DC) methods to identify potential water inrush hazards in coal mines. Their study, published in Applied Sciences, highlights the importance of advanced geophysical techniques for improving safety and operational efficiency in mining.
Study: Electromagnetic Response Characteristics and Applications of Numerical Simulation of Geoelectricity in Water-Rich Areas of Mines. Image Credit: Maksim Safaniuk/Shutterstock.com
Detection Reliability Through Geophysical Techniques
The mining industry faces significant risks from water inrush incidents, especially as mining depths increase. Traditional detection methods often lack the reliability needed to identify water-rich zones before excavation. Geophysical techniques such as TEM and DC resistivity are critical because they assess subsurface conditions non-invasively by detecting differences in electrical properties between water-bearing zones and the surrounding rock.
TEM, which relies on electromagnetic induction, is highly sensitive to low-resistivity anomalies associated with water-rich areas, making it effective for long-distance detection. In contrast, DC resistivity involves injecting current into the ground and measuring voltage differences to map variations in near-surface resistivity. While each technique has its advantages and limitations, their combination provides a more comprehensive approach for detecting water-bearing anomalies in complex underground environments.
Development of a 3D Geoelectric Forward Model
This study introduced a novel three-dimensional (3D) geoelectric forward model using COMSOL Multiphysics to simulate the electromagnetic responses of water-rich anomalies around mines.
Researchers integrated TEM and DC resistivity techniques to evaluate their combined effectiveness in detecting water-bearing targets within approximately 40 meters of the roadway. Using geological and detection data from the Tashan Coal Mine, they developed a full-space geoelectric framework that incorporated the geometry of the mine tunnel and the electrical properties of the surrounding strata/landscapes.
Simulations examined the influence of different anomaly positions, orientations, and azimuthal angles on the response characteristics of each method. The DC modeling employed a three-pole electrode configuration, while TEM focused on magnetic induction responses. The sensitivity of each technique was then compared under various spatial conditions to understand how integration could improve detection accuracy.
The response patterns observed during the simulations were applied to field data from the Tashan Coal Mine, where underground drilling confirmed the presence and orientation of the predicted water-rich zones, validating the accuracy of the 3D framework. This approach established a robust method for interpreting geophysical data in mining environments.
Key Insights on Detection Effectiveness
The outcomes showed that both TEM and DC methods were effective in detecting water-bearing anomalies within a 40-meter radius of the roadway. TEM demonstrated high sensitivity at longer distances and performed best when anomalies were located within an azimuthal range of 30° to 45°, highlighting the value of anomaly orientation for accurate detection.
The DC resistivity method was particularly effective for identifying shallow, near-field anomalies, indicating clear low-resistivity signatures when close to the current source. However, its effectiveness declined sharply beyond 40 meters. In contrast, TEM was better at detecting low-resistivity targets at greater distances, though its performance remained influenced by the anomaly’s azimuthal angle.
The simulations further demonstrated that apparent resistivity curves and amplitude responses were strongly affected by the distance between the source and the anomaly, emphasizing the need for close-range surveys in practical mining applications. Field tests validated the numerical results, confirming the predicted locations and orientations of water-rich zones, and subsequent drilling verified the accuracy of these detections.
Practical Applications for Mining Safety
This research has significant implications for improving safety in coal mining operations. By accurately identifying water-rich zones before excavation, the combined methods enable mining companies to anticipate water-related risks more effectively and mitigate the risk of water inrush incidents. The findings indicate that the DC performs best within a detection range of about 40 meters, while TEM is most effective when anomalies lie within azimuthal angles of 30° to 45°. It can be valuable for planning safe excavation strategies in areas prone to water hazards.
The validated modeling approach also supports the development of more advanced detection technologies customized to underground mining environments. By improving the accuracy of subsurface imaging, this framework enhances risk management, supports optimized mine planning, and contributes to safer and more efficient mining operations.
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Conclusion and Future Directions
The combined use of TEM and DC methods significantly improved the accuracy of detecting anomalies in coal mines. The findings demonstrated that the DC method is effective for identifying anomalies, while the TEM method extends the detection range and provides better sensitivity to anomaly orientation. Together, these techniques can serve as a reliable early-warning system, supporting safer tunnel excavation and mine planning.
Future work should focus on developing real-time monitoring systems and improving detection equipment to address water inrush hazards. Further refinement of these methods and exploration of additional geophysical approaches will enhance safety protocols in mining operations. This integrated framework lays a foundation for advancing risk assessment and promoting safer, more efficient, and sustainable mining practices.
Journal Reference
He, Y. et al. (2025) Electromagnetic Response Characteristics and Applications of Numerical Simulation of Geoelectricity in Water-Rich Areas of Mines. Applied Sciences, 15(23), 12566. DOI: 10.3390/app152312566. https://www.mdpi.com/2076-3417/15/23/12566
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