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Intensive and massive coal mining causes a series of geological hazards and environmental problems, especially surface subsidence. In recent years, backfill-strip mining has been applied to control mining subsidence in order to realize sustainable development of the mining environment. To accurately predict the surface subsidence of backfill-strip mining, a prediction method of subsidence superposition of backfill-strip mining is proposed on the basis of the traditional probability integral method prediction model. In analyzing the distribution of the actual subsidence space, the surface subsidence problem of backfill-strip mining can be regarded as the superposition of surface subsidence caused by backfill mining and strip mining. Then, the appropriate prediction parameters will be chosen, and the surface subsidence caused by the backfill mining and strip mining will be predicted separately. The surface subsidence values of the backfill-strip mining are equal to the superposition subsidence values predicted by the backfill mining and strip mining prediction method at the same surface location. A similar material model and a numerical simulation model have been built to verify the feasibility and accuracy of the superposition prediction method. The comparison results of the surface subsidence values show that the superposition surface subsidence prediction method is reasonable. The average relative error of this superposition prediction method is less than 6.7%, and its accuracy is 3.9%~11.4% higher than that of the conventional prediction method. The superposition prediction method can satisfy the precision requirement of engineering applications. This study provides a scientific technical reference for safe mining engineering design and surface disaster protection for backfill-strip mining.

Underground coal excavation has caused a series of geological disasters and environmental problems, especially coal mining subsidence. Backfill-strip mining, which combines the advantages of strip mining and backfill mining, can reduce subsidence and improve the recovery rate of coal. Therefore, predicting the impact of backfill-strip mining on the surface environment and strata structure is essential for the better development of backfill-strip mining technology. Here, a scientific and comprehensive mechanical model is creatively proposed. The mechanical model is divided into two systems at the main key strata (MKS): the lower strata of the MKS are regarded as a rectangular plane mechanical model on the Winkler foundation, comprising spaced filling bodies and coal pillars, and the upper strata of the MKS are regarded as a space-layer mechanical model. First, the subsidence function of the MKS is proposed. Then, this function is transmitted to the space-layer mechanical model through the interface. Finally, the mechanical model is used to predict the subsidence of the strata and the surface. The feasibility of the model is verified by numerical simulation and similar material simulation, and the characteristics of strata movement are analyzed. Using the mechanical model, the influences of geological and mining conditions on strata movement are discussed. This provides theoretical guidance for the study of strata movement and mechanisms in backfill-strip mining.

In order to safeguard the surface structures from mining damage while optimizing the liberation of coal resources under the dense surface buildings of the Cedi River coal mine. Considering that the analysis of the structure and type of surface buildings and the geological mining conditions of the mine, a wide strip mining design with a retention width of 70 m and a mining width of 50 m was finally determined by using the pressure arch theory and Wilson’s theory, combined with the actual layout of working faces 51,002, 51,004 and 51,006 at the site.The strip mining design is verified by probability integral method and FLAC 3D numerical simulation calculation respectively, The findings indicate that the highest value of earth surface subsidence created by the mining of the wide strip is 210 mm, the surface horizontal deformation value is 1.0 to − 1.4 mm/m, the damage to surface buildings is less than Level I, which satisfying the prerequisites of the surface building protection level, and can realize the continuous advancement of mine 51,002, 51,004 and 51,006 working faces, The coal pillars of the retained strip have sufficient support strength and long-term consistency, and the movement and deformation of the overburden after mining will not cause undulating subsidence of the surface, which effectively solve the mine's technical difficulties in safely coal mining under surface buildings.

The dynamic subsidence disaster caused by underground mining of coal resources is a complex spatiotemporal process, which is a common disaster in mining areas. The backfilling strip mining technology is a green and sustainable coal mining method, which has been commonly used to reduce the subsidence disaster of the overlying strata and protect surface buildings. The transient deformation is the main reason of surface buildings damage; therefore, in this study, the similar material model was used to research dynamic deformation characteristics of the overlying strata in backfilling strip mining at different time scales, and the optical image method was employed to monitor and obtain the movement data of the overlying strata automatically. The data analysis shows that there is a time-scale effect in mining subsidence. The deformation of the overlying strata increases instantaneously at a certain time under the monitoring of small time scale, and this phenomenon gradually disappears as time scales increase. According to the subsidence velocity of small time scale, the subsidence state of the overlying strata can be further divided into the abrupt subsidence state and the gentle subsidence state. This is really significant for promoting the development of the backfilling strip mining technology and preventing the damage of surface buildings.

In consideration of the high filling costs and backfill material shortage at present, backfill–strip mining, which combines the advantages of strip mining and backfill mining, has gradually been adopted to control surface subsidence. In this study, similar material modeling is established to simulate strata movement characteristics of backfill–strip mining. The displacement and deformation values of this similar material modeling are precisely acquired through close-range photogrammetry and optical image methods, respectively. On this basis, structural and movement characteristics of the overlying strata are investigated in different stages to reveal the strata subsidence control mechanism of backfill–strip mining. The dynamic deformation characteristics of the overlying strata in mining are also explored. This study provides a scientific technical reference for safe mining engineering design and surface disaster protection for backfill–strip mining.

Backfill-strip mining is proposed as a sustainable mining method to address the shortage of backfill material and high filling costs at present. The overlying strata in backfill-strip mining are mainly supported by the combined support pillar (CSP) of the residual coal pillar and the filling body. The stability of the CSP in backfill-strip mining is important to control the surface subsidence and reduce surface environmental damage. The particle flow code (PFC) simulation method is used in this study to investigate the deformation characteristics, failure behaviours, and stress distribution of the CSP for assessing its stability. The different influencing factors of the stability of the CSP, including geological mining factors, backfilling mining techniques, and the sizes of the residual coal pillar and the working face, are discussed. The results show that the shape of the CSP looks similar to a saddle. The vertical stress of the coal pillars is larger than that of the filling body. The subsidence value of coal pillars is smaller than that of the filling body, but the horizontal movement value of the coal pillars is large. Among these influencing factors of the stability, the residual coal pillar width has the greatest influence on the CSP. The different widths of the residual coal pillar lead to changes of the support formation and the bearing stress weight of the CSP, which make a big difference in the stress distribution characteristics, the movement deformation characteristics, and the stability of the CSP. On this basis, the CSP is divided into four types according to the stability and the support characteristics of the CSP, and their deformation characteristics and stability are summarised. The research results are important for guiding the stability assessment of CSP in backfill-strip mining and preventing the subsidence disaster whilst promoting sustainable extraction of coal resources.

This book is a comprehensive account of the hydrogeological procedures that should be followed when performing open pit slope stability design studies. Created as an outcome of the Large Open Pit (LOP) project, an international research and technology transfer project on the stability of rock slopes in open pit mines, this book expands on the hydrogeological model chapter in the LOP project's previous book Guidelines for Open Pit Slope Design (Read & Stacey, 2009; CSIRO PUBLISHING).This book offers slope design practitioners a road map that will help them decide how to investigate and treat water pressures in pit slopes. It provides guidance and essential information for mining and civil engineers, geotechnical engineers, engineering geologists and hydrogeologists involved in the investigation, design and construction of stable rock slopes.

The stability of backfill strips is a central focus in strip backfill mining, as it determines both the design rationale and the applicability range of this mining technique. However, analytical approaches for evaluating backfill strip stability remain underdeveloped. In this study, a novel aeolian sand-based paste backfill material was developed using aeolian sand as the aggregate and alkali-activated fly ash as the binder. The resulting material exhibits high fluidity and substantial strength, offering a cost-effective and high-performance backfill solution for coal mining in aeolian sand-rich regions. A numerical simulation model for strip backfill mining was established, showing that the plastic zone width of aeolian sand-based backfill strips increases with greater mining height and depth but decreases with a higher area filling ratio. Through ternary linear regression, an empirical equation was derived to relate plastic zone width to these three parameters. By comparing the mechanical behaviors of backfill and coal strips and integrating A.H. Wilson’s two-zone constraint theory with King’s effective area theory, a stability expression for backfill strips was formulated for the first time. Field verifications demonstrated that the proposed stability analysis method for aeolian sand-based paste backfill strips is both rational and accurate, providing a reliable theoretical basis for engineering applications.

Considerable coal resources are buried under buildings in No. 5 mining area of Hengjian Coal Mine, which greatly shortens its service life. Working on the premise that the degree of mining-induced damage to surface buildings should not exceed the protective indicator, the mine proposes to use super-high water backfill technology so as to ensure maximum exploitation of these resources. However, according to monitoring of observations of surface movement in the first-mined 2515 working face, mining-induced damage to the surface buildings will exceed level I if this technology is also used to exploit other working faces. A technology combining super-high water backfilling with strip mining is proposed. Numerical simulation is used to study the influence of different retaining pillar widths on surface subsidence characteristics. A reasonable design of these combined technologies is achieved based on the numerical simulation and theoretical analysis. Predicted results indicate that the designed scheme can ensure the safety of the surface buildings. These research results provide a reasonable and reliable technical solution for mining of coal resources buried under buildings.

Coal is West Virginia's bread and butter. For more than a century, West Virginia has answered the energy call of the nation and the world by mining and exporting its coal. In 2004, West Virginia's coal industry provided almost forty thousand jobs directly related to coal, and it contributed $3.5 billion to the state's gross annual product. And in the same year, West Virginia led the nation in coal exports, shipping over 50 million tons of coal to twenty-three countries. Coal has made millionaires of some and paupers of many. For generations of honest, hard-working West Virginians, coal has put food on tables, built homes, and sent students to college. But coal has also maimed, debilitated, and killed.Bringing Down the Mountains provides insight into how mountaintop removal has affected the people and the land of southern West Virginia. It examines the mechanization of the mining industry and the power relationships between coal interests, politicians, and the average citizen. Shirley Stewart Burns holds a BS in news-editorial journalism, a master's degree in social work, and a PhD in history with an Appalachian focus, from West Virginia University. A native of Wyoming County in the southern West Virginia coalfields and the daughter of an underground coal miner, she has a passionate interest in the communities, environment, and histories of the southern West Virginia coalfields. She lives in Charleston, West Virginia.