Research on the Correlation Between Overburden Rock Fracture Development and High-Energy Events During Deep Mining in Extremely Thick and Weakly Consolidated Strata for Regional Coal Mining Safety

Abstract

The environmental damage and mining accidents caused by water inrush accidents and rock burst are two major problems faced in the safe and sustainable deep mining of extremely thick weakly cemented overlying strata. Mastering the fracture development law of the overlying strata, the evolution characteristics of high-energy events, and their correlative relationships in the deep mining of extremely thick weakly cemented overlying strata is the key to solving the above two problems, which is directly related to the sustainable development of regional coal and the protection of underground water resources in mining areas. By integrating the geological characteristics of extremely thick and weakly cemented overburdens in the Shaanxi–Inner Mongolia mining region of China, this study adopts methods such as field measurements, numerical simulations, and theoretical analyses to investigate the energy evolution characteristics of regional mining-induced tremors, as well as the correlation and mutual influence mechanisms between overburden fracture development and high-energy events. The results indicate a positive correlation between high-energy events and the development height of overburden fractures, suggesting that the occurrence of high-energy events can increase the height of overburden fracture development. Furthermore, high-energy events occurring before and after the “parallel joining” of two working faces have a relatively minor impact on the development height of overburden fractures, with an increase in the fracture-to-mining ratio (FMR) ranging from 1.56 to 2.78. In contrast, high-energy events occurring during the “parallel joining” of two working faces significantly affect the development height of overburden fractures, resulting in an FMR increase of 10.33 to 13.44, approximately one-third of the FMR measured through boreholes. The research results can provide a scientific basis for the safe and sustainable coal mining and the protection of underground water resources in similar mining areas with extremely thick weakly cemented overlying strata.