The mining of layered soft bauxite under coal seams (BCS) will cause serious underground goaf disasters and surface Bayer process red mud (BRM) pollution. In order to realize the safe and efficient mining of BCS, the feasibility of recycling BRM as a backfilling aggregate was explored. A series of tests were conducted to prevent the pollution diversion of BRM from surface storage to underground goafs, and a numerical simulation analysis of the backfilling mining process was carried out based on FLAC^3D to protect the overlying coal seam. The results show that: under the action of encapsulation, solidification and inhibiting precipitation from cementitious materials, the leaching concentration of harmful substances in red mud-based cemented backfill (RCB) can be reduced 70% more than fresh BRM. Mining disturbance redistributes the in-situ stress field of overlying strata; normal backfilling can not only reduce the pressure stress of pillars, but also release the tensile stress in the roof and floor from +0.4956 MPa to −0.1992 MPa, effectively preventing roof subsidence. Since the creep damage process of past backfill will absorb and dissipate lots of energy, the disturbance range caused by backfill mining is controlled within 3 m, which is only 10% of the open-stope method.

Despite China’s position as a global mining powerhouse, tens of thousands of small- and medium-sized mines (SM mines) within the country continue to pose potential safety hazards and environmental pollution risks. Only through the identification of suitable development paths can these mines improve their economic and environmental benefits, ultimately driving significant progress in China’s mining industry. Backfill mining, an environmentally friendly mining method, has emerged as a viable solution, offering the potential to ensure mining safety, reduce environmental pollution stemming from tailings stockpiles, and enhance ore resource recovery. This review article aims to provide researchers and readers with a comprehensive understanding of the current situation and challenges faced by SM mines in China. It explores the mining processes, technologies, and equipment commonly employed by these mines while addressing the specific problems and challenges they encounter. Furthermore, the article offers recommendations to guide the future development of SM mines. Additionally, the review examines the prospects and potential applications of backfill mining methods within the context of SM mines in China, emphasizing their role in promoting sustainable mining practices, environmental protection, and waste utilization. Ultimately, this comprehensive review article serves as a valuable resource, stimulating discourse and encouraging experts and scholars to further explore the unique challenges and opportunities associated with SM mines. By highlighting the significance of green mining practices, environmental protection, backfill mining, and waste utilization, the article aims to inspire innovative solutions and foster sustainable practices within the Chinese mining industry.

In Suichang gold mine, the altered rock type gold deposits were cut by faults and joint fissures, leading to complex resource endowment characteristics, large changes in occurrence, a serious complex of ore vein branches and great difficulty in mining. In order to select a suitable mining method for such a difficult and complicated orebody, a multi-factor and multi-index comprehensive evaluation system involving benefits, costs, safety and other aspects was constructed by using the Pythagorean fuzzy sets and TOPSIS method. Taking Suichang gold mine as an example, the weighted aggregation evaluation matrix was constructed, the closeness index of the four mining schemes were 0.8436, 0.3370, 0.4296 and 0.4334, and the mechanized upward horizontal layering method was determined as the optimal scheme. This method overcame the fuzzy comparison of economic and technical indicators directly, but converted them into corresponding fuzzy numbers to obtain accurate closeness index for optimization. The application of this method not only ensured a safe, efficient and environment-friendly mining effect, but also provided a reference for the optimization of the mining scheme of the severely branched composite orebody.

In the mining industry, with numerical simulation analysis of stope roof stability, stope exposed area computation, and pillar buckling collapse simulation, backfill body creep damage mechanism research is becoming the most popular method in the field of backfill mining techniques. In this paper, we first summarized and analyzed the current application status and the existing problems of numerical simulation for solving mining engineering technical problems; then, based on the practical engineering problems of mining phosphate rock resources under high and steep rock slopes (HSRS), we carried out a true-3D numerical simulation study for different underground mining methods, to determine the appropriate mining method. Therefore, this paper, taking Dingxi Mine in China as an example, highlights the advantages of the backfill mining method with a high and steep slope; meanwhile, it also points out how to improve the accuracy of a numerical simulation and make it more consistent with the actual situation of the mining engineering application site. This paper only serves as a guide, in order to start a conversation, and we hope many more experts and scholars will become interested and engaged in this field of research.

The stability of high and steep slopes in open-pit mines is closely related to the mine operations and the lives of the surrounding residents, so it is important to ensure the safety and stability of the slopes. Hazard classification and stability analysis of high and steep slopes under different working conditions are studied using the Shizhuyuan non-ferrous metal mine from underground to open-pit mining as a typical example. Firstly, data on rock mechanics parameters were obtained through site investigation and sampling. Then, the slope model of the open-pit mine was established and some slopes were selected in the model for qualitative and quantitative analysis. The strength reduction method and the limit equilibrium method were used to calculate the safety factor under each working condition and point out the potential instability areas. The results show that the selected slopes are safe and stable under all working conditions. Finally, on the premise of maintaining the safety and stability of the mine, the final slope angle was optimized from the original 45°21′35″ to 55°30′41″ to reduce production costs and increase mining efficiency. The final open-pit boundary that meets the stability requirements was eventually obtained.

The stability of mine slopes is an important factor influencing the orderly production of mines and the safety of people’s lives and property. The stability of slopes can be effectively determined by means of three-dimensional simulation analysis. Some 3D simulation analysis methods are based on 2D analysis, and are still essentially 2D analysis methods, whereas this digital simulation analysis uses a true 3D analysis method. This method can reflect the overall slope stability of the mine in a more realistic way, and at the same time, the situation of the selected sections can be observed, making the analysis more scientific and rigorous. This study takes the Shizhuyuan Nonferrous Metal Mine as an example and studies the safety stability of mine slopes through true 3D safety analysis. The results show that the open-pit slopes of the Shizhuyuan mine are stable. The overall model results show that there is only a small amount of tensile damage and no penetration; the section results show that the absolute value of tensile stress is generally small, with a maximum of 1.45 MPa being less than the tensile strength of the material (7.04 MPa). After the model monitoring simulation, it is found that the displacements of each monitoring point are in the process of fluctuation and then stabilisation, which can also indicate that the slope is finally in a stable state. Comparing the above results with the conclusions obtained from the 2D analysis method, the conclusions are found to be in general agreement, indicating that the true 3D simulation analysis method is effective and feasible.