Application of Controlled-Source Audio-Frequency Magnetotelluric Method and High-Density Resistivity Method in Precise Water Control in Metal Mines

After mine closure, the underground drainage system within the mining area must continue operating to pump out goaf water, resulting in persistently high equipment operation and maintenance costs. To fundamentally reduce drainage energy consumption and operational expenses while blocking groundwater recharge pathways, a curtain grouting project was decided to be implemented in the upstream area of the mining area's hydrogeological unit. The inversion results of the Controlled-Source Audio-Frequency Magnetotelluric (CSAMT) method can effectively delineate fault width, depth, structural variations of fault blocks, and stratigraphic changes. A steep gradient in resistivity is a significant indicator for identifying fault presence. The High-Density Resistivity (HDR) method is a combined exploration technique integrating electrical sounding and electrical profiling with multiple arrays and electrode spacings. It offers advantages such as low cost, high efficiency, rich information acquisition, and convenient data interpretation. This paper focuses on the combined application of CSAMT and HDR in a mine water control curtain grouting project. Using a specific water control project in a mining area of Zibo City as a case study, and based on the working principles of HDR and CSAMT, the study targeted the detection of underground karst fissures. Resistivity distribution profiles were obtained. Based on geophysical interpretation and inference, key investigation zones were delineated. Subsequently, drilling verification and curtain grouting were conducted in these key zones. This process effectively validated the accuracy of CSAMT and HDR and provided effective guidance for the curtain grouting engineering.