As mining depths increase, the synergistic effect of high in-situ stress and complex geological environments leads to frequent rock burst incidents. However, there is carrently a lack of comprehensive evaluation methods for the rock burst proneness of deep rock masses that accounts for multi-factor influences. Based on rock mechanics parameter tests conducted at an iron mine in the Xinjiang Uygur Autonomous Region, the rock burst proneness of the rock mass in the -450 m to -600 m level was evaluated using four indicators: the strength brittleness coefficient, the improved brittleness index, the maximum storage elastic strain energy, and the strain energy index. The results indicate significant dispersion among the evaluation results obtained by using different single indicators, rendering it difficult to accurately determine the actual rock burst proneness relying solely on an individual metric. Consequently, a comprehensive evaluation model for rock burst proneness was established by integrating the fuzzy mathematics method and the entropy weight method. A comprehensive assessment of the sandstone rock burst proneness in the -450 m to -600 m level of the mine was performed, revealing a moderate rock burst proneness across all cases. On-site investigations demonstrate that the evaluation results generated by the multi-indicator comprehensive evaluation method based on fuzzy mathematics align closely with the actual in-situ damage conditions, facilitating an accurate assessment of the rock burst proneness grade. These findings provide a rock bust theoretical basis and technical support for safe mine production and rock burst mitigation.

Deep vertical shafts are critical passages for deep resource development, and their surrounding rock stability is essential to guarantee the safety and efficiency of mining. Aiming at the surrounding rock stability problem of shaft walls in broken rock mass, taking the Xiling mining area of Sanshandao Gold Mine as the engineering background, a three-dimensional numerical model of the vertical shaft was established by using the Bonded Block Model (BBM) in the discrete element software. The damage and failure characteristics of shaft walls at buried depths of 1 600-2 500 m were investigated, and six support and reinforcement schemes for shaft walls in high-stress and broken rock mass conditions were proposed. The results show that the deformation and failure behavior of surrounding rock in deep vertical shafts under high in-situ stress is affected by horizontal geostress. With the increase of buried depth, the maximum displacement and deformation range of shaft wall surrounding rock increase. The displacement in the maximum principal stress direction changes significantly, and the minimum principal stress direction is the main concentration area of shear stress. Broken rock strata increase the mechanical complexity of shaft wall surrounding rock, and the dynamic action of broken rock mass may cause spalling of rock blocks and failure of surrounding rock. Grouting bolts can effectively improve the stress state of the support structure and disperse the concentrated stress in the surrounding rock. After support, the displacement of the shaft wall is reduced by 53%-65%, and the shear stress concentration zone is transferred to the shallow part at 0.5-1 m depth of the shaft wall. For different buried depths, reasonable support and reinforcement measures can effectively control the dynamic action of broken rock mass and reduce the failure risk of shaft walls.

With the acceleration of deep-sea development, the conflict between discharge risks and legal regulatory conflicts arising from deep-sea mining in international seabed area needs to be resolved. To this end, starting with a fundamental interpretation of mining discharges, a systematic review of the game process for mining discharge regulations within the "region" was conducted, revealing the fragmented and ambiguous nature of the current international legal framework. By analyzing the challenges in applying the international legal regime for mining discharges, the disconnect between domestic and international laws, and the lag in environmental risk prevention mechanisms, the key difficulties in governance were identified. It further proposes establishing a collaborative mechanism for legal interpretation under a dynamic system, advancing substantive development through inter-convention institutional cooperation, and designing tiered and categorized risk prevention and emergency response mechanisms to achieve coordinated optimization of mining discharge regulations. Against the backdrop of China's strategic requirements, the nation can transition from a rule-follower to a rule-setter by revising domestic deep-sea mining legislation, deepening regional cooperation, and actively championing proposals such as the "negative list" on international platforms. This approach not only offers a viable solution for the negotiation and cooperation on deep-sea mining discharge regulations within the "area", but also provides a practical model for global governance.

Addressing the challenges of complex and variable boundaries, low ore recovery rates, extensive roof exposure areas, and a low degree of mechanization associated with high-altitude tourmalinite-type massive orebodies, this study systematically analyzed the occurrence characteristics of the orebody to facilitate safe, efficient, and green mining operations. Four technical mining schemes were proposed, and their respective advantages, disadvantages, principal technical and economic indexes were comprehensively evaluated. Consequently, the upward drift filling mining method was identified as the optimal extraction scheme. The maximum allowable exposed areas of the orebody and surrounding rock were determined using the Mathews stability graphical method. Coupled with numerical simulations, the distribution patterns of stress, vertical displacement, and plastic zones under varying drift dimensions were elucidated, establishing the optimal drift parameters as 5 m in width and 3.5 m in height. On-site industrial tests demonstrate that the maximum roof subsidence of the stope is 19.2 mm, with no occurrences of collapse. Furthermore, the ore loss and dilution rates are 3.2% and 3.5%, respectively, representing significant reductions of 8.8 and 8.5 percentage points compared with the shallow-hole shrinkage mining with subsequent backfill method. These findings establish a robust technical paradigm for analogous mines and propel the sustainable development of high-altitude mineral resources.

Addressing the issue of top pillar recovery beneath the overlying graded tailings backfill at the Liutangfang Iron Mine in Anhui, this study first comprehensively determined the maximum recoverable thickness of the top pillar using the load transfer line intersection method, the thickness-to-span ratio method, and the Protodyakonov arch theory. Subsequently, the maximum exposed area of the top pillar under varying stope widths was established via the Mathews stability chart method. Finally, incorporating on-site mining practices, numerical simulations of excavation were performed for two mining methods (cross-vein and strike-vein) across five stope structures. A comprehensive analysis was conducted to evaluat roof settlement, stress distribution, plastic zones, and excavated ore volume under different mining methods and stope structural parameters. The results indicate that for a stope span of 6 m, the safe thickness of the top pillar is 5 m. Based on the actual hydraulic radius derived from the Mathews stability chart method, the calculated maximum stope drift length is 30 m. When the strike-vein mining method is employed, the roof settlements corresponding to different drift pillar widths are 16 mm, 18 mm, and 20 mm; when cross-vein mining method is used, the maximum roof settlement is 33.52 mm, with the maximum roof stress increasing by 0.1 MPa. A comprehensive comparative analysis reveals that adopting the strike-vein mining method with a 4 m drift pillar keeps roof settlement within a controllable range, thereby optimally satisfying the safety, efficiency, and economic prerequisites of mine production. This scheme is projected to recover approximately 480 000 tons of top pillar resources, ensuring a smooth transition in mine production capacity and providing a reference for similar engineering projects.

Against the backdrop of panel mining utilizing the stage open stoping with subsequent backfill method during the transition from open-pit to underground mining at Sijiaying Iron Mine, three stope mining sequence schemes were proposed: "from one side to the other" "from the center to both sides", and "from both sides to the center". A numerical simulation approach was employed to investigate the stress field distribution characteristics, displacement variations, and plastic zone propagation laws of the surrounding rock in the panel stope under different mining sequences. Ultimately, the "from the center to both sides" sequence was determined to be the optimal mining scheme for this mine. The results are shown as follows. Firstly, across the three mining schemes, the compressive stress following stress release, the tensile stress, and the maximum internal displacement within the surrounding rock consistently exhibit a trend of "from the center to both sides" < "from both sides to the center" < "from one side to the other". Secondly, under the "from the center to both sides" scheme, the compressive stress and maximum tensile stress of the surrounding rock following stress release are 1.58 MPa and 0.35 MPa, respectively, with a maximum internal displacement of 37.765 mm; these values are universally superior to those of the other two schemes. Finally, following panel extraction, the total volume of the plastic zone in the surrounding rock, and the volume ratio between the tensile plastic zone and the total plastic zone, exhibit the same variation law as the surrounding rock stress field and displacement field. Specifically, the "from the center to both sides" scheme yields a total plastic failure volume of 34.73×10⁴ m³ and a tensile plastic zone ratio of 60.60%, both of which outperform the alternative schemes. These findings hold significant implications for guiding the design and future production of the mine during its transition from open-pit to underground operations.

To address the problem of a large amount of overlaid ore by the shaft safety pillar in a gold mine, numerical simulation calculations method were carried out to analyze the influence of different delineation angles of the safety pillar on the stability of the shaft and surrounding rock, and the safety pillar range was re-delineated. The numerical simulation results show that the influence of mining of No.13 ore vein of the mine on shaft stability increases with the increase of the delineation angle of the safety pillar. When the delineation angle of the safety pillar exceeds 75°, ground pressure behavior is significantly intensified, and there exists a risk of shaft instability, especially after the stoping of deep stopes. Therefore, it is recommended that the delineation angle of the safety pillar be controlled at 75° and below to ensure the safety of the shaft. When the delineation angle of the safety pillar is increased from 65° to 75°, the volume of overlaid ore in the safety pillar is reduced from 1 192 955.0 m³ to 545 256.7 m³.About 54.3% of ore resources can be released, which improves the utilization rate of mineral resources and is conducive to the sustainable development of the mine.

The high content of phosphogypsum gel material has the disadvantages of weak gelling and low strength. Adding lime can improve the gelling and strength of phosphogypsum-based solid waste gel material. Phosphogypsum, steel slag and blast furnace slag were used as raw materials of cementitious materials, lime was used as activator, and tailings were used as aggregate to prepare backfill. The mechanical characteristics, pore characteristics and microstructure of backfill under different lime content were investigated. The fractal theory was introduced to explore the effect of lime on the pore characteristics of phosphogypsum-based solid waste cementitious backfill. The results show that a lime content of 2% increases the 7-day and 28-day strengths of the backfill by 133.33% and 95.83% respectively, which is the best lime content. Excessive lime generates excessive Ca(OH)₂ crystals, which causes volume expansion and structural damage of the backfill, thereby reducing its strength. Lime has a significant effect on the small pores in the backfill, especially on the fractal dimension of the pores within 20-200 nm. The strength of the backfill decreases linearly with porosity, decreases exponentially with pore contents in the ranges of 20-100 nm and >200 nm, decreases quadratically with pore content in the range of 100-200 nm, and increases exponentially with the fractal dimension.

Caving mining is widely recognized to trigger large-scale strata movement and ground deformation, making a reliable delineation of the surface subsidence range essential for mitigating associated losses. In this study, a representative metal mine adopting the caving method was investigated, and the subsidence range was evaluated using numerical simulation, analytical modelling, and similarity simulation model test. Numerical simulations were first performed to obtain a preliminary subsidence profile. On this basis, an enhanced Weibull-distribution-based formulation was developed to better capture the subsidence characteristics induced by caving mining in metal mines. The spatial uncertainty of rock-mass mechanical properties was then incorporated via reliability theory to provide a reliability-informed prediction of the subsidence range. Finally, the analytical predictions were validated by similarity simulation tests. The three approaches yield subsidence extents in the following ascending order: numerical simulation < similarity simulation test < reliability-based analysis. The discrepancy between theoretical predictions and test results ranges from 0.30% to less than 5%, demonstrating the robustness and credibility of the proposed method for subsidence-range delineation.

To reveal the energy evolution law of open-pit mine dumps under seismic conditions and establish a criterion for slope instability, the cusp catastrophe theory was combined with the energy theory in open-pit mine dumps. This led to the development of a theoretical instability model for dissipated energy catastrophe, using slope dissipated energy as state variable. The south dump of Dasuji Molybdenum Mine was taken as the engineering background. FLAC3D software was used to analyze the evolution patterns of dissipated energy of four slope sections in the south dump and analyze the mutation characteristics. Based on these findings, the stacking scheme of the dump was optimized. The results show that most of the characteristic values of the dissipated energy for the south dump slope section are below zero, and the slope is prone to instability under seismic loading. The simulation results are consistent with the field situations. According to the evolution characteristics of the dissipated energy of the slope, an optimization scheme of "slope reinforcement+stacking optimization+monitoring and early warning" is proposed and applied to the south dump. The numerical simulation analysis and field monitoring verification of the optimized scheme show that the anti-deformation ability and overall stability of the slope are significantly improved after taking the optimization measures. The research results can provide references for the preventing dump slope instability.