Development and Height Prediction of Fractured Water-Conducting Zone in Weakly Cemented Overburden: A Case Study of Tashidian Erjingtian Mine

To clarify the development and height of the fractured water-conducting zone of underground mines with weakly cemented overburden, the W8203 working face of the Tashidian Erjingtian Mine in Xinjiang, China, was selected to carry out a case study. Firstly, a physical analog model test was conducted to investigate the development law of the water-conducting fracture zone, followed by a numerical simulation via the PFC2D program. Afterward, a theoretical analysis based on the key stratum theory was carried out. The results demonstrated that there were one primary key stratum and three sub-key strata upon the W8203 working face. As verified by the physical analog tests, the water-conducting fracture developed to the bottom of the primary key stratum, and the height of the fractured water-conducting zone was 246.38 m. The numerical analysis suggests that the primary key stratum did not completely break and the fracture did not penetrate the stratum. Theoretical calculation indicated that the primary key stratum maintained stability in the structure without any breakage. The height of the fractured water-conducting zone is comprehensively determined to be 246.38 m, which is relatively close to the measured value (229.32 m). Based on the prediction method of key stratum position combined with the characteristics of weak cemented overburden, a method to predict the height of a water-conducting fracture zone suitable for weak cemented overburden was developed. The accuracy of this method was also verified through an in-depth comparison with field test results. Under the background of the “strategic westward shift” of coal resource exploration and development in China, the research results can provide theoretical and technical support for safe production in the Tashidian Mining Area and references for green and safe production in weakly cemented overburden mining areas in western China.