Application of Transient Electromagnetic Method for Investigating the Water-Enriched Mined-Out Area

Chuantao Yu,Xinyue Liu,Shuaibin Yan,Jishan Liu,Peng Yue,Enguo Li

doi:10.3390/app8101800

Abstract

The water-enriched mined-out area, which led to frequent accidents and the serious destruction of ecological environment and serious threat to coal-mining practices. To ensure safe mining practices and to avoid the intrusion of water from the bases of coal deposits, the detection of the mined-out areas, especially the water-filled mined-out area in advanced, is one of the most important issues. This research focuses on detecting mined-out area enriched by water with the large-loop transient electromagnetic method. Data acquisition system was arranged along 23 survey lines, and the total of 1975 survey points were recorded. An inversion technique was used to interpret the TEM data. The inversion results suggested that the mined-out areas enriched by water always exhibit a very low-resistivity, the resistivity contour present closed circle sharp. There are three main water enriched mined-out areas, named JS1, JS2, and JS3 in the north part of the survey area, as well as three main water weak-enriched areas named RJS1, RJS2 and RJS3 in the west and southwest part of the survey area can be inferred by TEM, the interpretation results were verified by drilling. Large loop TEM is proved as an efficient way to investigate water enriched mined-out areas under the rugged topography conditions, and this work provides more detailed geological information to the coal mining enterprise for further coal-mining practices safety arrangement.

Highlights

China is currently the world’s largest coal miner, and it is the largest consumer of coal in the world [1,2,3,4,5,6]
Mined-out areas of different scales will occur, which results in unstable stress and it brings stress concentration
Mined-out areas can be water filled, when water inrushes or surface water leaks through cracks into excavated areas, surface damage that is caused by subsequent subsidence might appear [11]

Summary

Introduction

China is currently the world’s largest coal miner, and it is the largest consumer of coal in the world [1,2,3,4,5,6]. The start of the 21st century was a golden era for the coal sector, and the rapid expansion of coal firms led to huge profits [7,8]. Based on China’s existing technologies, the mining coal lead to huge mined-out regions. Mined-out areas of different scales will occur, which results in unstable stress and it brings stress concentration. Under the action of overlying rocks, deformation, cracking and dislocation will occur, leading to the formation of caving zone, fracture zone, and bent deformation belt [9,10]. A typical collapsed area can be divided into three zones, such as Caving zone, Fault zone, and crooked zone, as shown in Figure 1 [11,12,13,14]

Methods

Results

Conclusion