Search

The Yangjiacun coal mine, located in western China, exhibits distinctive characteristics, such as its shallow depth, thick bedrock, thin loose layer, and unique roof strata breaking movement. In this research, a comprehensive analysis of previous exploration data, subsequent mechanical testing, key stratum theory, natural equilibrium arch theory, and simulation tests and numerical simulations has been conducted to investigate the failure behavior of the overlying rock strata in the Yangjiacun Coal Mine. Specifically, the load‐bearing capacity of the key stratum structure in the bedrock and the morphological properties of the arch‐beam structure have been thoroughly examined. A mechanical model of the roof rock arch‐beam structure has been established, and an analytical formula for the limit size and stability criterion of the arch‐beam structure has been derived. The mining‐induced rock arch‐beam structure plays a crucial role in transferring the load of the upper strata to the surrounding goaf, thereby preventing subsidence and deformation of the overlying strata. However, the arch‐beam structure periodically experiences instability during the advancement of the working face, gradually progressing towards the upper layer until the main key stratum is breached and the arch‐beam structure collapses. Based on the characteristics of weathered rock and the arch‐beam failure model in the Yangjiacun Coal Mine, quantitative backfilling mining methods have been proposed to either compensate for the mining void created by coal extraction or limit the size of exposed key strata through strip mining, ensuring the stability of the R6 key stratum. This study represents a significant contribution to understanding the intricate failure behavior of overlying rock strata in coal mines and provides a valuable framework for the responsible and efficient extraction of coal resources in similar environments. [ABSTRACT FROM AUTHOR]

Fault coal bursts is a common type of coal bursts in coal mining. With increases in mining depths and mining intensities, the occurrence frequency and disaster degree of coal bursts in fault‐controlled areas are increasing in severity. Therefore, in this article, the mechanism and control method of deep mining‐induced fault coal bursts are analysed on the No. 3402 longwall panel controlled by two faults in the Shandong Mine, China. Based on the microseismic monitoring data of the longwall panel, the fault activation process induced by mining can be divided into four stages. The second energy release and fault activation stages are risk stages of fault coal bursts. Using numerical simulation, the evolution laws of vertical stress, elastic strain energy in front of the longwall panel, and the ratio of shear stress to normal stress on fault plane are investigated. The phenomenon of a 'high elastic energy section‐low elastic energy section' coal pillar between faults is revealed, and the mechanism of coal pillar coal bursts induced by high elastic energy is discussed. Third, based on the above research results, coal burts risk areas of the longwall panel in the fault‐controlled area are determined. The method of 'coal seam‐roof‐floor coupling destressing with the reduction in mining speed' to control fault coal bursts is introduced. Field test results show that the method effectively destroys the integrity and bearing capacity of the coal seam, significantly reduces the energy storage capacity of the superposition area of mining stress and fault tectonic stress, so that the coal bursts risk of the coal seam in the fault control area is relieved, ensuring safe and efficient mining of the longwall panel. The method can provide a reference for other coal mines with similar geological conditions. [ABSTRACT FROM AUTHOR]

Coal burst has become one of the most serious hazards in longwall coal mines of many countries, and extensive studies have been conducted on the mechanism, prediction, and prevention of coal bursts. However, most of these studies focus on qualitative descriptions of burst environments and specific case analyses. Few studies have been carried out to explore knowledge through a number of past coal bursts in longwall mines. The main objective is to quantitatively analyze the current burst‐prone conditions in longwall coal mines of China and to summarize corresponding lessons. A database consisting of 54 major coal bursts was established. The characteristics and contributing factors of involved coal bursts were analyzed quantitatively, and high‐risk areas that are common in coal mines were then identified. Finally, some suggestions and lessons were proposed. This study may help for identifying controlling factors and high‐risk areas at a specific mine, and it might provide insights into the control of coal bursts in longwall coal mines. [ABSTRACT FROM AUTHOR]