THE DUAL LOOP CONFIGURATION OF THE TRANSIENT ELECTROMAGNETIC METHOD

Geophysics ◽  
1975 ◽  
Vol 40 (6) ◽  
pp. 1051-1057 ◽  
Author(s):  
Brian R. Spies
Keyword(s):  
Electromagnetic Method ◽  
Scale Model ◽  
Transient Electromagnetic Method ◽  
Strongly Coupled ◽  
Extra Time ◽  
Model Studies ◽  
Transient Electromagnetic ◽  
Main Disadvantage ◽  
Ground System ◽  
Time Required

The transient electromagnetic method offers considerable advantages over conventional electromagnetic systems; these advantages make the method attractive under typical Australian conditions of conductive overburden. A common transient electromagnetic ground system used in Australia is a combined loop version in which the same loop is used for transmitting and receiving. This system employs a horizontal loop which is strongly coupled to horizontal conductors. By means of scale model studies and a field example it is shown that an alternative loop configuration is a system in which two adjacent loops are connected in parallel, the “dual loop” configuration. It provides improved detectability of a vertical or steeply dipping conductor. In addition, the dual loop configuration reduces electrical interferences. The main disadvantage of this configuration is the extra time required to lay out a dual loop.

Configuration Detection of Substation Grounding Grid Using Transient Electromagnetic Method

2017 ◽  
Vol 64 (8) ◽  
pp. 6475-6483 ◽  
Author(s):  
Cigong Yu ◽  
Zhihong Fu ◽  
Gaolin Wu ◽  
Liuyuan Zhou ◽  
Xuegui Zhu ◽  
...  
Keyword(s):  
Electromagnetic Method ◽  
Transient Electromagnetic Method ◽  
Transient Electromagnetic ◽  
Grounding Grid

scholarly journals Application of Comprehensive Geophysical Prospecting Method in Water Accumulation Exploration of Multilayer Goaf in Integrated Mine

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Lei Zhang ◽  
Lin Xu ◽  
Yong Xiao ◽  
NingBo Zhang
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Comprehensive Analysis ◽  
High Density ◽  
Electromagnetic Method ◽  
Mine Safety ◽  
Practical Significance ◽  
Time Base ◽  
Transient Electromagnetic Method ◽  
Transient Electromagnetic

A coal mine in Datong is an integrated mine. At present, there is goaf in the upper and lower part of the mining coal seam. There is a lot of ponding in the goaf, which has great potential safety hazards for production. In order to find out the scope and location of ponding in goaf, the comprehensive geophysical exploration method combining transient electromagnetic method and high-density resistivity method is used to carry out the research. Firstly, the time-base, turn-off time, receiving delay, current, superposition times, and other parameters of the instrument are tested on the surface of known goaf to obtain the best instrument parameters, and the parameters are used to verify the feasibility of the research scheme; then, the transient electromagnetic method is used for large-area exploration on the surface of the mine, the suspected goaf ponding area is found through comprehensive analysis, and the high-density resistivity exploration is arranged in the suspected goaf ponding area. According to the obtained results, the scope and location of the goaf ponding area are accurately located through comprehensive analysis. The results show that there are two goaf ponding areas in the exploration area, which are located above the 8# coal seam currently mined; the range and location of goaf ponding area can be accurately obtained by using the comprehensive geophysical method of high-density electrical method and transient electromagnetic method. This method can provide reference for mine water prevention and control in Datong area and has great practical significance to ensure coal mine safety production.

The Development of Near-source Electromagnetic Methods in China

2018 ◽  
Vol 23 (1) ◽  
pp. 115-124 ◽  
Author(s):  
Guo-qiang Xue
Keyword(s):  
High Efficiency ◽  
Academic Research ◽  
Electromagnetic Method ◽  
Detection Accuracy ◽  
Wide Field ◽  
Transient Electromagnetic Method ◽  
Transient Electromagnetic ◽  
Detection Technology ◽  
Deep Depth ◽  
Central Loop

Near-source electromagnetic technology has been developed and applied in the exploration of petroleum, metallic ore, coal, and engineering geology due to its high efficiency, high detection accuracy, and deep depth of investigation. In this paper, research and applications of the frequency-domain electromagnetic sounding method (FDEM), wide-field electromagnetic method (WFEM), modified central-loop transient electromagnetic method (TEM), and short-offset grounded-wire TEM (SOTEM) with obvious near-source characteristics, were reviewed and analyzed. From the 1960s to 1990s, the FDEM method and equipment were extensively developed in China. These methods have played important roles in the exploration of coal resources. Based on controlled source audio-frequency magnetotelluric (CSAMT) and FDEM methods, a new method has been developed by deriving a new expression to calculate apparent resistivity. This method, which is referred to as WFEM, has been studied, applied, and received great attention in China. To increase work efficiency and reduce the influence of local transverse anisotropy on the detection processes, a modified central-loop TEM detection technology based on the central loop transient electromagnetic method was developed in China. The advantages of SOTEM in near-source surveys with high resolution and increased depth detection stimulated academic research interest to further develop grounded-wire TEM techniques. [Figure: see text]

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