Study on the joint detection of coalfield ‘skylight’ structure by high-density resistivity method and transient electromagnetic method

Abstract The water-conducting channel formed between adjacent aquifers is called ‘skylight’, which is an important factor leading to water and water-sand inrush accidents in coal mines. In order to find out the possible spatial position of the ‘skylight’ structure in a coal mine, the opposing coil’s transient electromagnetic method(OCTEM) and the high-density resistivity method are utilized for joint detection. Combined with geological data to interpret the resistivity section of the transient electromagnetic method, the position of low resistance anomaly is delineated. The results of the data are processed by 3D visualization. The results of the data are a ‘funnel-shaped’ structure in 3D space. Meanwhile, The findings in the high-density resistivity method further indicate that the resistivity at the delineated anomalous location exhibits a notable decrease compared to the resistivity of the adjacent rock formations.The results of the two methods verify each other and confirm the development position of the ‘skylight’ structure. The research shows that the combined detection of the transient electromagnetic method and high-density resistivity method can better identify the ‘skylight’ structure of coalfield, and can provide a safe geological guarantee for coal mine production, which has good application value and promotion significance.