Research and Application of the Mine 3D DC Resistivity Method for Detecting Grouting in the Floor of an Ultrawide Working Face, Taking the Yongmei Xinqiao Coal Mine in Henan Province as an Example

Generally, ground grouting is used to treat confined water areas before mining at the working face, but there is a lack of testing methods for determining the effectiveness of such a grouting treatment on the floor of ultrawide working faces. Therefore, we propose a 3D DC resistivity method for mines and apply it to the detection of the effect of grouting on the mine floor. This study took the Yongmei Xinqiao Coal Mine in Henan Province as the research object and used a combination of theoretical analysis, numerical simulation, and measured data analysis to study the effect of the 3D resistivity method on detecting the effect of grouting on the floor of an ultrawide working face in the mine. The research results indicated that compared with the 2D observation mode of same-side power supply and reception, the 3D observation mode of opposite-side power supply and reception using the tunnels on both sides of the working face was more sensitive to the response of the water-rich area 60 m below the coal seam's floor. Regarding the model's set-up in this article, when traditional apparent resistivity calculations were used, the apparent resistivity obtained by the 3D observation mode was opposite to the model's setting, and accurate electrical information of anomalous bodies must be obtained through 3D inversion. The measured data showed that although the ground grouting treatment effectively reduced the water volume in the floor, the treatment's result was affected by human factors, and the water in the floor was redistributed.