Synthetic Aperture Imaging in Advanced Detection of Roadway Using Mine Transient Electromagnetic Method

Abstract

During the data processing and interpretation of mine transient electromagnetic method (MTEM), in order to improve the identification of the geo-electrical interface between low resistivity abnormal body and surrounding rock in advanced detection, transient electromagnetic field was transformed to pseudo-seismic wavefield based on the function relationship between spreading electromagnetic field and seismic wave-field in wholespace. Meanwhile, the signal of pseudo-seismic after being transformed was processed with correlative stack to strengthen the amplitude and improve signal-noise-ratio (SNR) using the synthetic aperture imaging (SAI). The data of different detection directions on one surveying point in MTEM were imaged as aperture data, which would highlight weak abnormality and improve SNR. In addition, the application effect of SAI was testified with the in-site advanced detection in roadway using MTEM. The results showed that the SAI of the MTEM could improve SNR of the electrical interface information and highlight the geometrical resolution to increase exploration accuracy. The technique is significant theoretically and practically in accurate advanced detection of aquifer structure by MTEM.

2.5-D Inversion of Advanced Detection Transient Electromagnetic Method in Full Space

“…Moreover, this criterion accepts the poor adaptable solution with a certain probability to make particles avoid local extrema and premature termination of the algorithm. Particles gradually converge to the global optimal solution when the annealing temperature is adjusted in the criterion, which is expressed in (9). The Metropolis criterion can be expressed as follows [22]:…”

“…Currently, 1-D inversion, which uses a linear or approximate inversion method from a single point, is the main method used for processing and interpreting mine TEM. The 1-D inversion results, which cannot show the prolife of geological information accurately, are usually combined pointby-point to form a pseudo 2D section [9]. Thus, applying 2.5-D inversion method in actual conditions is necessary [10].…”

Maxwell-equations Based on Mining Transient Electromagnetic Method for Coal Mine-Disaster water Detection

“…At present, the geophysical exploration methods are popular to predict coalmine water disaster. Representative geophysical method include mine direct current method [2], radio wave penetration method, audio frequency electric penetration method and mine transient electromagnetic method (MTEM) [3]. Among these methods, MTEM is widely used in the detection of advanced heading face.…”

Study on metal interference correction method in mine TEM based on the fitting function

“…Due to the urgent need for coal mine water prevention and control, China University of Mining & Technology introduced the transient electromagnetic method into coal mine roadway detection in 1998, and began to make use of SIROTEM-3F and terraTEM to do some MTEM experiments and application works. Since then, the application and technology of MTEM has obtained great improvement over the last decade [9][10][11][12][13][14] .…”