In the 17^# thick and large ore body of Zone Ⅲ at Yinman Mining, kaolinized fracture zones develop non-uniformly in the hanging wall and footwall, leading to a high risk of stope collapse and easy softening of the filling body. The conventional upward horizontal cut-and-fill mining method struggles to balance safety and economic efficiency. To address this issue, a progressive zonal cooperative mining concept of "central stable zone-peripheral fracture zone" was constructed. Five methods were employed to calculate the required filling body strength for different zones. Combined with three-dimensional numerical simulation, the effects of mining sequence, stope width, and safe exposure area on the stability of the surrounding rock and filling body system were analyzed. The results indicate that the alternating mining sequence of "extracting one leaving one" (Scheme 3) is the optimal option. This scheme can confine the high-risk plastic zone to approximately 5-7 m within the roof and control the single safe exposure area to approximately 300 m². After adopting the zonal cooperative mining method, the daily production of stopes in the fracture-affected zone stabilizes at 390-400 t. The development ratio and cost per ton of ore are significantly reduced, and roof subsidence is controlled within a range of 30-40 mm. The production capacity of a single sublevel increases to 4 500 t/d, representing an improvement of 60.7%, while the filling cost decreases to 66.3 yuan/t, a reduction of 25.5%. Consequently, the zonal cooperative effects of "improving efficiency and reducing costs while controlling risks and enhancing stability" are achieved.

To achieve the safe and efficient mining of resources under fractured ore-rock conditions in the first mining area of a copper-gold mine, numerical simulation was used to optimize the process parameters of the drift section, the mining spacing of the panel, and the multi-layer collaborative mining interval of the upward drift filling mining method. The feasibility of the optimized parameters was verified through the field industrial test. The results show that the influence of drift width variation on the roof differs for different roof media. The drift section dimensions are determined to be 5 m×5 m, and the interlayer spacing of multi-layer collaborative mining should be not less than 20 m. A "mining one drift after every three drifts" scheme is implemented in the panel area, i.e., the spacing between simultaneously mined drifts in the panel is 15 m. The optimized process parameters were applied to the field industrial test, achieving safe, efficient, and economical mining under unstable ore and rock conditions, indicating that the optimized process parameters are feasible applied to the first mining area of the mine.

To investigate the influence of stope width and stoping sequence on the bearing capacity of panel pillars, this study takes the panel mining using the stage open-stope with subsequent backfill mining method in Sijiaying Iron Mine as the engineering background. The stress response and deformation failure characteristics of panel pillars under different stope widths and stoping sequences were analyzed, and the optimal mining scheme was selected. The research results are as follows. Firstly, stope width and panel stoping sequence jointly influence the stress response characteristics of panel pillars. Under different stoping sequences, both the maximum principal stress and the minimum compressive stress within the pillars exhibit an increasing trend as the stope width increases. Secondly, stope width and panel stoping sequence jointly influence the deformation failure characteristics of panel pillars. Under the same stoping sequence, both the displacement of the pillars and the volume of the plastic zone increase with the increase in stope width. Finally, under the same stope width, the displacement of the pillars and the volume of the plastic zone rank from high to low in the order of "from one side to the other" "from both sides to the center", and "from the center to both sides". Taking into account safety and production capacity of the stope, the optimal mining scheme for this mine has been determined to be a mining width of 20 meters and a mining sequence of "from the center to both sides".

Aiming at the problem of high carbon emission and high cost of traditional cementitious material cement, a new type of cement-fly ash-carbonized steel slag ternary cementitious system (proportion of cement 40%, carbonated steel slag 30%, fly ash 30%) was proposed. Through the synergistic use of industrial solid waste, the goal of low carbon and low cost filling can be achieved. The results are concluded as follows. The reaction between CO₂ and active minerals in carbonated steel slag achieves carbon fixation and performance optimization. The flowability of the filling slurry in the cement-fly ash-carbonated steel slag system is better than that in the cement system. The ball rolling effect of fly ash and the optimized gradation of fine particles of carbonated steel slag synergistically enhance the rheological properties of the slurry. Due to the rapid reaction rate of cement, the 3 d compressive strength ratio of cement-fly ash-carbonated steel slag-based backfill to cement-based backfill is 0.45 to 0.65, while fly ash undergoes sustained hydration in the later stage to form hydration gel, the 7 d and 28 d compressive strengths ratio is increased to more than 0.80. The production cost of cement-fly ash-carbonated steel slag system is 22% lower than that of cement system, and the carbon emission is reduced by 63.6%. Through the resource utilization of steel slag, the problems of solid waste storage, filling cost and carbon emission have been solved simultaneously, which provides an innovative technical path for the goal of carbon neutrality in mining industry.

To address the prevalent issues of uneven rock fragmentation and high boulder rate in high-bench deep-hole blasting within high-altitude cold open-pit metal mines, an enhanced blasting technology utilizing water stemming for open-pit mines was proposed. A numerical simulation method was employed to investigate the spatiotemporal variation patterns of effective stress and damage within the rock mass after explosive detonation under two working conditions: fine sand stemming and water stemming. The mechanism of water stemming enhanced blasting was analyzed. Furthermore, blasting crater tests were conducted at the Xizang Julong Copper Mine to verify the accuracy of the numerical simulation results. The results indicate that during conventional blasting with fine sand stemming, the equivalent stress propagates upward slowly and unevenly, causing most of the blasting energy to concentrate at the bottom of the borehole, resulting in insufficient fragmentation of the upper rock mass. In contrast, during water stemming blasting, due to the incompressibility of water and its excellent stress transmission properties, the blasting stress propagates rapidly and uniformly through the water column to the middle and upper parts of the borehole, leading to effective fragmentation of both the upper and lower rock masses. Compared with fine sand stemming blasting, the upper water stemming blasting increases the maximum surface length, depth, and volume of the blasting crater by 13.33%, 12.07%, and 90.88%, respectively. The research results can provide a reference for efficient blasting and mining in high-altitude cold open-pit metal mines.

Aiming at the problems of roof over-excavation, roof failure and high block rate in the deep mining process of an iron mine, taking the ore body between －360 m and －450 m level of the mine as the engineering background, the optimization of blasting parameters for fan-shaped medium-length holes was carried out. Based on the mechanism of ore rock blasting fragmentation and the theoretical formula of blasting parameters, the theoretical value range of each blasting parameter was derived. Combined with the physical and mechanical properties of ore rock and the performance parameters of on-site explosives, Ansys LS-DYNA numerical simulation software was used to construct a stope blasting model with different hole bottom spacings, explosive unit consumption and resistance line combinations, and the effective stress distribution characteristics of the mine roof were analyzed. The results show that when the hole bottom spacing is 1.4 m and the explosive unit consumption is 2.09 kg/m³, the maximum effective stress of the monitoring grid in the room area is closest to the maximum dynamic tensile strength of the rock, which can fully break the ore rock in the hole bottom area, and the maximum effective stress of the roof monitoring grid does not reach the dynamic tensile strength, and the roof is stable. When the minimum resistance line is 1.6 m, the average maximum effective stress of the monitoring grid near the free surface is 44.31 MPa, and the peak value of blasting vibration velocity in the roof area is 18.51 cm/s, which does not exceed the allowable standard of blasting vibration safety. Based on the optimized parameters (hole bottom spacing 1.4 m, explosive unit consumption 2.09 kg/m³, minimum resistance line 1.6 m), the field industrial test was carried out. The bulk rate is reduced from 6% before optimization to 3%. The roof is well formed, the surface is flat, and there is no obvious crack and collapse. The research results can provide reference for the optimization of fan-shaped medium-length hole blasting parameters in similar deep filling stopes.

To investigate the collaborative optimization problem of blasting effect and drilling and blasting cost under complex working conditions in plateau open-pit mines, an integrated optimization method for hole network parameters combining multi-objective evaluation and numerical simulation verification based on the TOPSIS method was proposed. Based on the actual working conditions of a super-large plateau open-pit mine, the value ranges and comparison schemes of hole network parameters were determined in combination with parameters such as bench height and bench slope angle. Taking blasting effect and drilling and blasting cost as evaluation indexes, the predicted values of evaluation indicators for each comparison scheme were calculated by using the Kuz-Ram blasting fragmentation model and the drilling and blasting cost model. The TOPSIS method was employed to conduct a comprehensive evaluation and ranking optimization of each comparison scheme. Blasting damage numerical simulations for the comparison schemes were performed using the Ansys LS-DYNA software. The results show that the comprehensive scoring ranking of the five schemes is as follows: Scheme 3 (0.559) > Scheme 2 (0.544) > Scheme 4 (0.528) > Scheme 1 (0.507) > Scheme 5 (0.493), indicating that Scheme 3 achieves the highest comprehensive score. In the blasting damage nephogram of the optimal Scheme 3 (hole spacing of 10 m × row spacing of 8.5 m), the strongly fragmented zone, the fracture development zone, and the weakly damaged zone are evenly distributed. The blasting damage range achieves a relatively balanced control between effective fragmentation and excessive damage, thereby realizing an optimized balance between blasting effect and drilling and blasting cost. The research results can provide a reference for the optimization of blasting hole network parameters in open-pit mines.

The joint bedding structures in the roadway will change the stress propagation and failure mode of the rock mass under the blasting load, and affect the cutting blasting effect and driving efficiency. In order to reveal the influence mechanism of bedding structure on the response of cut blasting, a quasi-three-dimensional finite element model of roadway considering joint dip angle was constructed based on the engineering background of a mine roadway. The ALE fluid-solid coupling algorithm was used to compare and analyze the characteristics of stress wave propagation and damage evolution under the conditions without bedding and with bedding. The results show that the bedding structure significantly weakens the stress wave coupling strength, and the average effective stress decreases by 61.64%, which causes the difficulty in forming effective penetration in the central area of the cut. Regarding this issue, an improvement scheme for adding auxiliary cutting holes was proposed. The results of numerical simulation and field test show that the improved scheme effectively enhances the energy aggregation effect in the central area of the cut, and forms a typical "through-type high-damage channel". The rock mass is more fully broken, the continuity is better, and the bulk rate is significantly reduced. The research results can provide theoretical support and engineering reference for cutting blasting design under complex structural plane conditions.

In the transition process of open-pit to underground caving mining, with the deformation and fracture of the overlying surrounding rocks, its permeability increases sharply, which provides channels for heavy rainfall infiltration and easily induces disasters such as underground water inrush. In order to accurately evaluate the runoff infiltration in the subsidence area under heavy rainfall conditions, taking Shilu Iron Mine as the engineering background, a calculation method of rainfall infiltration based on the accurate division of surface catchment infiltration area was proposed. Hydrologic Engineering Center's River Analysis System (HEC-RAS) was used to delineate the catchment area outside the subsidence area. Combined with the numerical simulation results of surface subsidence deformation and surface catchment in the mining area, the infiltration areas such as caving zone, water-conducting fracture zone and runoff zone under different mining conditions were divided, and the rainfall infiltration under rainstorm conditions was calculated in different areas. The results show that the runoff infiltration in the subsidence area of the North No.1 stope increased from 182 874 m³/d under the current condition to 218 118 m³/d at the end of mining, with an increase of 19.3%. Three anti-seepage grade areas were further divided, and anti-seepage measures were proposed for different areas. Among them, the area where the caving zone and the water-conducting fracture zone were submerged by water was the first-level anti-seepage area, and the comprehensive anti-seepage measures of layered filling ground cracks, laying anti-seepage film and pumping were adopted. The research results can provide scientific basis for the design of mine drainage system and the prevention of water inrush disaster.

Aiming at the problem that the slope is easy to lose stability in the mining of ionic rare earth mines, and the traditional stability criterion method is difficult to quantify the uncertainty of dynamic multi-field coupling, a slope stability evaluation model based on game theory and cloud model was constructed. According to the four principles of uniqueness, purpose, feasibility and observability, a multi-dimensional evaluation index system covering geomechanical parameters, leaching process, slope geological conditions, hydrometeorological characteristics and regional geological characteristics was constructed. The game theory was used to optimize the subjective weight determined by the fuzzy analytic hierarchy process (FAHP) and the objective weight determined by the entropy weight method, so as to realize the collaborative weighting of subjective and objective weights. The cloud model was introduced to quantify the membership degree of slope stability, and the expectation, entropy and super entropy were used to characterize the random fuzziness of parameter values. An ionic rare earth mining area in southern Jiangxi was taken as an example for industrial application. The results show that the comprehensive stability scores of 1^#, 2^# and 3^# slopes in the mining area are 74.8 (sub-unstable), 58.9 (relatively stable) and 99.3 (unstable), respectively, which are consistent with the actual observation results and the calculation results of the improved AHP method. Compared with the traditional limit equilibrium method, the potential risks can be found in advance. It is verified that the game theory-cloud model can provide reliable discriminant results and has high-risk sensitivity. The research results provide a theoretical basis for the dynamic control of slope stability of ionic rare earth mines.

A rare earth mining area in Longnan County, Jiangxi Province, is affected by long-term mining operations and complex natural environments, and the slope stability problem is becoming increasingly prominent. Based on field investigation and data analysis, the geological and environmental conditions and slope stability characteristics of the study area were systematically evaluated. Physical and mechanical parameters of rock and soil mass were obtained through drilling, sampling and laboratory tests. Typical slope profile models were established by using Lizheng Geotechnical Software. On this basis, the circular slip method and broken-line slip method were adopted for computational analysis, and the slope stability under natural working conditions and rainstorm working conditions were simulated respectively. The calculation results show that under natural working conditions, the slope safety factor is 1.59, and the slope is in a stable state. Under rainstorm working conditions, the slope safety factor decreases to 0.913, and the slope is in an unstable state. Rainfall conditions significantly reduce the shear strength of soil mass and increase pore water pressure. Rainfall is the key factor triggering slope instability. The research results can provide a scientific basis for the formulation of slope protection measures in mining areas.

In view of the fact that Sijiaying Iron Mine does not have the condition of plane boundary expansion, it is necessary to set up the slope boundary pillar after the transition from open-pit to underground mining. The gravity increase method was adopted to study the stability of the slope boundary pillar after the transition from open-pit to underground mining. The evolution characteristics and laws of the stress field, displacement field and plastic zone of the slope boundary pillar under different gravity accelerations were obtained. The results show that under the condition of initial gravity acceleration of 1.0g, the 40 m thick slope boundary pillar can ensure the safety of underground mining and avoid instability of open-pit slope, such as collapse, caving and landslide. With the increase of gravity acceleration, the progressive instability failure of the slope boundary pillar can be divided into four stages: stable, slight deformation, serious deformation and instability failure. Slope boundary pillar is affected by the unloading of underground mining. The maximum principal stress is basically within 30 MPa, and the minimum principal stress and its distribution range increase greatly. The tensile stress value reaches more than 3 MPa, which is prone to tensile failure. The displacement field and plastic zone expansion characteristics of the slope boundary pillar are highly consistent with the tensile stress, expanding from the slope toe to the slope top on the west slope of the open pit. The research results have a certain guiding role in preventing and controlling slope instability after the transition from open-pit to underground mining.

Aiming at the problem that the impact vibration caused by roof caving threatens the stability of stope in caving mining, a physical simulation experiment was designed based on the mechanism of caving impact vibration and the similarity law of physical simulation. The relationship between the caving impact vibration velocity and the falling height of the caving body, the amount of one caving, the porosity of the cushion, the thickness of the cushion and the distance of the measuring point was systematically studied. The results show that the caving impact vibration velocity is positively correlated with the falling height of the caving body and the amount of one caving, and negatively correlated with the thickness of the cushion and the distance of the measuring point. With the increase of the porosity of the cushion, the caving impact vibration velocity decreases first and then increases. The correlation between the caving impact vibration velocity and each factor from high to low is the distance of the measuring point, the amount of one caving, the falling height of the caving body, the thickness of the cushion, and the porosity of the cushion. Based on the test results and the calculation method of blasting vibration velocity, an empirical formula for calculating the caving impact vibration velocity was constructed and applied to the west No.2 mining area of Jinchuan Longshou Mine. The maximum vibration velocities of roof caving at 1 595 m, 1 554 m and 1 494 m are 6.4 cm/s, 3.7 cm/s and 3.0 cm/s, respectively. The maximum vibration velocities measured in the field are 1.21 cm/s, 0.26 cm/s and 0.09 cm/s, respectively, which verifies the reliability of the measurement method. The research results can provide theoretical basis and practical guidance for the prevention and control of roof caving impact disasters in underground mines.

Research on slope deformation mechanism forms the foundation and key to formulating reasonable slope treatment measures. After slope cutting and load reduction combined with micro-pile treatment, a submerged slide zone in an open-pit mine in the Democratic Republic of the Congo experienced renewed deformation during subsequent deeper mining operations. To develop a treatment scheme for this submerged slide zone, field investigations and borehole surveys were conducted within the deformed area. The formation process of the sliding surface in the submerged slide zone was analyzed. Based on the investigation results, the deformation mechanism of the submerged slide zone was analyzed in detail. Ultimately, a treatment scheme centered on comprehensive slope cutting and localized reinforcement, comprising slope cutting and load reduction, large-diameter anti-slide piles, and soil nail walls, was formulated. The research results indicate that the formation of the sliding surface is predicated on geological tectonic processes. Under the disturbance induced by open-pit mining, continuous deformation occurs, and the sliding surface extends progressively downward, potentially coalescing to form an integral sliding surface in the final stage. The formation mechanism of the sliding surface in the submerged slide zone can be divided into three stages: the advancing-type sliding stage induced by unloading rebound, the retrogressive-type sliding stage triggered by excavation at the lower section, and the integral advancing-type sliding stage during later development. Based on the research findings regarding the formation mechanism of the submerged slide zone, a combined treatment measure incorporating slope cutting and load reduction, soil nail walls, and anti-slide piles was formulated. The rationality of the treatment scheme was verified through computational analysis. The research results can provide a reference for the study of treatment measures for similar soft rock slopes in open-pit mines.

To address the issue that the dust dispersion mechanism in open-pit mines under the influence of multiple factors remains unclear, this study takes the Qidashan open-pit mine as the engineering background. A numerical simulation method was employed to analyze the effects of multiple factors, including wind speed, wind direction, dust particle size and dust source location, on the dust dispersivity. Furthermore, the spatiotemporal distribution characteristics of dust under multiple dust source conditions were investigated. A three-dimensional flow field model of the Qidashan stope was constructed based on on-site meteorological data. Simulation analyses of the dust dispersivity were conducted under various working conditions. The results indicate that dust particle size is the primary factor influencing the dust dispersivity; the smaller the particle size, the higher the dispersivity. Wind speed ranks second, exerting a significant effect on dust particles larger than 30 μm. In contrast, dust source location and wind direction have relatively minor effects on the dust dispersivity. Moreover, under multiple dust source conditions, dust accumulates within the stope and disperses along the wind direction as the duration of continuous dust production extends. After dust production ceases, the dust concentration gradually decreases. The dust dispersion velocities from different source points exhibit significant differences due to variations in their locations. Affected jointly by terrain and airflow, the PM_2.5 concentration exhibits a variation pattern of "increase-decrease-increase" as the stope depth increases. Based on the research findings, relevant measures and recommendations for dust prevention in production at the Qidashan open-pit stope are proposed, with a focus on dust source control, suppression of the transmission process, and differentiated precise prevention and control.

Ground fissures accelerate land degradation and soil erosion, and induce secondary geological disasters such as landslides and collapses. To reveal the development characteristics of ground fissures under high-intensity mining conditions, relevant research was carried out with the 615 working face of a mine as the engineering background, and multiple methods including field measurement, experimental simulation, theoretical analysis and engineering application were comprehensively utilized. The results show that ground fissures are mainly divided into tensile, step and collapse types according to different deformation properties. During the advance of the working face, the propagation period of fissures within the working face is shortened and the closure degree decreases. The development degree of ground fissures is more significant than that under conventional geological and mining conditions. The number of fissures with widths of 0-100 mm, 100-500 mm and greater than 500 mm accounts for 38%, 56% and 6%, respectively. Overburden fissures develop synchronously with the breaking of thick and hard rock strata and eventually penetrate the ground surface. Based on the critical deformation values of ground fissures, the fissure angle along the strike, the fissure angle on the dip side, and the fissure angle on the rise side are predicted to be 79.8°, 74.1°, and 79.5°, respectively, with a maximum relative error of 7.1%. In addition, the calculation formula for the critical depth-thickness ratio of through fissures was proposed. The research results are of important reference significance for land remediation and geological disaster prevention in mining areas.

To investigate the fracture distribution law of rock strata under hydraulic fracturing in gently inclined hard roofs and to determine the critical initiation stress range of hydraulic fracturing, this study takes the I010206 working face of Kuangou Coal Mine as the engineering background. Based on the mechanical properties of the roof surrounding rock, similar material specimens were prepared. Using a true triaxial hydraulic fracturing experimental apparatus, physical simulation experiments under different stresses and initiation pressures were conducted under stress conditions of σ_H=12.8-13.9 MPa, σ_h=6.5-8.1 MPa, and σ_v=5 MPa, with a water injection flow rate of 40 mL/min. Furthermore, numerical simulation software was employed to analyze the three-dimensional spatial distribution characteristics of the fractures. The results show that the horizontal stress difference has a significant influence on the fracture propagation morphology. Under low stress difference conditions, fractures exhibit unilateral dominant propagation, with the scaled-up propagation area reaching 4.25 m². Under high stress difference conditions, fractures are symmetrically double-winged, with increased propagation resistance and a reduced area of 3.84 m². The number of acoustic emission events ranges from 3 698 to 4 702, and the peak amplitude ranges from 83.2 to 121.1 dB. The evolution characteristics are related to the height of fracture initiation and propagation. The initiation pressure range for hydraulic fracturing in the hard roof of this mine is determined to be 10.80-16.79 MPa, and a critical initiation pressure of 16.79 MPa is recommended as the lower engineering limit. Engineering application results demonstrate that these fracturing parameters can significantly reduce the suspended roof area and markedly lower the risk of rock bursts. The research results can provide theoretical support and engineering reference for the design of roof fracturing schemes and disaster prevention and control in deep mines.

Aiming at the failure mechanism and control problem of surrounding rock of deep buried solid coal rectangular roadway under thick loose layer and thin bedrock overburden structure, the influence of horizontal stress on the surrounding rock load of this kind of roadway was studied through engineering field investigation, numerical simulation, theoretical derivation and case application. Taking Guotun Coal Mine as the engineering background, the failure characteristics of surrounding rock of solid coal rectangular roadway under thick loose layer and thin bedrock overburden structure were revealed. According to the ground stress characteristics of deep buried roadway, the arch axis equation of balanced arch considering horizontal stress was deduced based on the balance of force and moment. The calculation method of surrounding rock load of rectangular roadway based on the improved model of balanced arch was proposed and programmed, which improved the analysis theory of balanced arch. The effectiveness of the improved balanced arch model was verified by engineering examples and two research cases, and the influencing factors of the failure height of the roadway vault and the roof load were analysed. The results show that the failure of the surrounding rock at the top of the rectangular roadway presents three obvious zones, namely, the broken caving zone, the fracture affected zone and the non-affected zone. The error between the damage range of the vault and the side calculated by the proposed theoretical method and the numerical simulation results is 7.4% and 14.0% respectively, and the error between the proposed theoretical method and the field detection results of similar roadway is 25.0% and 18.4% respectively. The comparative analysis results of the two engineering cases verify the rationality of the improved model of the balanced arch. The failure height of the roadway vault and the roof load decrease nonlinearly with the increase of the lateral pressure coefficient, and decrease linearly with the increase of the internal friction angle of the fragmentation. The research results have important guiding significance for the design of bolt/anchor cable support in this kind of roadway.

Coal permeability directly affects the efficiency of gas extraction. Using the multiphase and multifield true triaxial dynamic seepage test system of coal and rock, combined with acoustic emission monitoring, ultrasonic testing and high-resolution image processing, the fracture structure and permeability evolution of in-situ coal subjected to hydraulic fracturing with low-concentration ammonium persulfate were investigated, and the influence mechanism of five groups of different liquid injection rates and pressure injection spaces (the action space between fracturing fluid and coal wall in the open hole section) was quantitatively analyzed. The results show that the larger the liquid injection rate is, the shorter the time required for coal to fracture is, the larger the pressure injection space is, the lower the coal fracture pressure is, and the 4-hole fracturing tube (the largest pressure injection space) has the most acoustic emission positioning points and the widest distribution. After hydraulic fracturing, the ultrasonic velocity of five groups of coal samples decreased. Compared with water fracturing, the coal fractured with ammonium persulfate has fewer acoustic emission positioning points (lower damage), but the oxidation and dissolution of ammonium persulfate can further improve the degree of fracture development, and the effect is better in improving coal permeability. Under the same conditions, the larger the pressure injection space is, the wider the range of coal fracture penetration and ammonium persulfate action is, and the more significant the permeability improvement is. When the pressure injection space is the same, the lower the liquid injection rate, the better the permeability improvement effect. The synergistic effect of oxidation dissolution of ammonium persulfate and hydraulic fracturing can promote the expansion of coal fracture network, and the pressure injection space affects the fracture expansion range and density. The research results can provide theoretical guidance for the modification of seepage characteristics of low permeability coal seams.

In order to study the stage mechanical response characteristics of dry and water-saturated siltstone during splitting process, Brazilian splitting test was carried out, and the stage division method of full stress-strain curve of rock splitting process based on splitting modulus was established. The response law and mechanical mechanism of stress characteristic value and strain characteristic value in each stage were systematically analyzed. The results show that water significantly affects the stress evolution path and strain development path of Brazilian splitting process in siltstone. The average values of compaction stress, yield stress, peak stress and unloading stress of water-saturated samples decrease to 62.65%, 50.21%, 48.93% and 68.11% of dry samples, respectively. The average value of stress ratio in compaction stage increases by 28.50%, and the average values of stress ratio in elastic stage, yield stage and failure stage decrease by 19.60%, 41.35% and 11.99%, respectively. The average values of compaction strain, yield strain, peak strain and unloading strain of water-saturated samples are 4.12%, 19.26%, 20.70% and 17.92% lower than those of dry samples, respectively. The average value of strain ratio in compaction stage increases by 20.38%. The average values of strain ratio in elastic stage and yield stage decrease by 29.64% and 36.93%, respectively, and the average value of strain ratio in failure stage increases by 347.73%. Saturated treatment enhances the plastic characteristics of splitting process. After saturated treatment, the bending energy index of siltstone decrease by 73.77%, and the impact tendency decrease from class Ⅲ to class Ⅱ. The research results can provide theoretical basis for water injection softening and anti-impact technology of deep mine roof.

Aiming at the calculation problem of soil pressure in foundation pit engineering, an analytical method for soil pressure was established, and the influence effects of various factors were analyzed. Based on the basic assumptions of Coulomb's soil pressure theory, and fully considering the friction angle between the wall back and backfill, the soil internal friction angle, foundation pit excavation depth and other factors, a soil pressure calculation model was constructed, and quantitative formulas for soil pressure and its influence range induced by excavation disturbance were proposed. Through the sensitivity analysis of influencing factors, the influence order of each factor on the excavation influence range was clarified under the conditions with or without steel supports. The variation laws of the influence range under different working conditions and excavation stages were studied, and comparative verification was carried out. The results show that the distribution patterns of soil pressure along the foundation pit excavation depth from the two methods are consistent, which verifies the accuracy of the model. Sensitivity analysis shows that the excavation depth of a foundation pit exerts the most significant effect on the excavation influence range without supports, and the excavation depth of the foundation pit remains the main controlling factor after steel supports are installed. The model proposed in this paper can quantitatively analyze the soil pressure distribution and disturbance influence range during the foundation pit excavation of a 110 kV substation as part of a supporting project of an energy development base in Hefei, Anhui Province. The results can provide a theoretical reference for the design and analysis of foundation pit engineering of related energy and mineral resources development infrastructure.

Benefit evaluation of geological environment restoration aims to serve the prediction of the benefits of geological environment governance in abandoned mines and the assessment of the effectiveness of restoration, providing reliable decision-making support and effective supervision methods for restoration engineering practices. Through the review of domestic and foreign literatures and the cluster analysis of relevant influencing indicators, combined with the triple bottom line theory and sustainable development theory, a benefit evaluation index system for the geological environment restoration of abandoned mines was constructed from four dimensions, including economy, society, ecology, and sustainable development. The analytic hierarchy process (AHP) and entropy method were used in combination to assign weights to the indicators, and the fuzzy comprehensive evaluation method was used to construct the restoration evaluation model. The model was empirically applied in the geological environment restoration project of historical abandoned mines in Zhangjiakou city. The results show that the evaluation result benefit of geological environment restoration of abandoned mines in the city is 89.85, and the restoration effectiveness level is good. The ecological and social benefit evaluation values are relatively high, indicating that the case project has generally achieved the restoration goals of eliminating hazards, improving the ecology, and enhancing functions. The sustainable development and economic benefit evaluation values are relatively low, and measures still need to be optimized from aspects such as improving maintenance systems and mechanisms, strengthening publicity and education, and implementing dynamic monitoring and supervision to further improve the comprehensive benefits of restoration. The proposed evaluation index system and model are scientific and feasible, and can effectively evaluate the benefits of geological environment restoration in abandoned mines, providing a reference for the benefit evaluation of similar projects.

Aiming at the pain points of heavy assets, high energy consumption and low reliability of equipment in traditional aggregate plants, the Distributed Control System (DCS) has been adopted. Through the implementation of hardware redundancy configuration, Modbus communication protocol integration and advanced control algorithm, the DCS designed and optimized the whole process of crushing, screening, sand making and water circulation control in Zhuzailing Aggregate Factory. The application effect of DCS in material balance, equipment monitoring and energy consumption management were analyzed. The results show that since the system has put into operation, the no-load energy consumption of the equipment is reduced by 15%, and the comprehensive energy consumption is reduced by 18%. The average fault interval time is increased from 1 200 h to 2 100 h, the average repair time is shortened by 47%, the comprehensive efficiency of the equipment is increased from 74% to 89%, and the turnover rate of spare parts is increased by 62%. The whole life cycle of the equipment is extended by 3-5 a, and the annual production capacity is increased by 150 000 tons. At the same time, the technical problems such as signal interference, lightning strike and power fluctuation in high dust environment have been solved. DCS can systematically improve the energy efficiency, reliability and intelligence level of aggregate plants, and provide engineering reference for the green and intelligent transformation of similar enterprises.

Flotation of cassiterite is a critical step for the efficient utilization of complex mineral resources. Based on domestic and international research, a systematic review of the research progress in the development of cassiterite flotation reagents and the mechanisms of interfacial interactions was conducted. Based on the surface anisotropy of cassiterite crystals, the distribution of active sites on the (110) (100) and (101) crystal planes was analyzed in detail. The synergistic adsorption mechanism among multiple crystal planes was elucidated, and the coordination chemistry of metal ions (such as Pb²⁺ and Fe³⁺ ) in surface activation was revealed. In terms of the pharmaceutical system, molecular design strategies for novel hydroxamic acid derivatives, phenylphosphonic acid derivatives, and environmentally friendly amino acid-based collectors were reviewed, noting that targeted functional group modification can effectively enhance chelation selectivity toward Sn sites. In terms of mechanism of action, composite agents significantly enhanced interfacial adsorption density through chelation and synergistic adsorption. For example, the combination of hydroxamic acid and fatty acids formed a multilayer adsorption structure, while cationic-anionic composite collectors reinforced both electrostatic and coordination interactions. Composite inhibitors such as polyacrylic acid-lignosulfonate achieved precise inhibition of calcium and magnesium gangue minerals through steric hindrance and selective adsorption. Future research should focus on establishing a quantitative relationship among "molecular structure, adsorption configuration and flotation performance", and combining with computational chemistry methods to advance the rational design and industrial application of green, high-efficiency reagents.

To address the environmental hazards caused by red mud stockpiling during Bayer process alumina production and achieve efficient utilization of secondary resources, this study takes Bayer process red mud as the research object. It systematically reviews the fundamental characteristics and environmental risks of red mud, focusing on the current research status of recovering valuable metals such as Fe, Al, Ti and Sc. The study provides an in-depth comparison of the operational principles and industrial application effects of different recovery processes, and analyzes the advantages, disadvantages, and applicable scenarios of each process. Research findings indicate that the physical method for Fe recovery features simple operation but achieves a recovery rate of only 55%-60%. The reduction roasting-magnetic separation method can attain a recovery rate of 87%-92.8%, albeit with relatively high energy consumption. Acid leaching methods yield relatively high leaching rates for Al, Ti, and Sc recovery, but suffer from high acid consumption. Combined processes can enhance overall recovery efficiency, though they involve complex flowsheets. Currently, the comprehensive utilization rate of red mud has increased to approximately 12%, yet a gap remains compared with that of developed countries. Front-end phase regulation, the development of green processes, the advancement of combined processes, and the preparation of high-value-added materials from red mud represent the core development directions for future valuable metal recovery from red mud. This review can provide a reference for technological upgrading within the industry.

The precipitation extraction process of rare earths from ionic rare earth ore by ammonium salt leads to eutrophication of receiving water bodies and disruption of aquatic ecological balance. It also triggers cascading ecological issues such as soil acidification and compaction in surrounding areas, as well as threats to human health. To address this ammonia nitrogen pollution problem, the leachate from an ionic rare earth mine in Longnan was taken as the research object. A light-burned, ammonia-free, high-activity magnesium oxide precipitant was prepared, and its influence on the rare earth precipitation behavior was investigated. Meanwhile, XRD, SEM, and TG-DTG characterization techniques were employed to systematically compare and analyze the precipitation products derived from different magnesium oxide systems. The results show that the reactivity of the prepared magnesium oxide is significantly higher than that of industrial magnesium oxide. Using active magnesium oxide slurry as the precipitant under the optimal precipitation condition (molar ratio of 8, reaction temperature of 90 ℃, and reaction time of 4 h), a precipitation product with a purity of 37.45% and a precipitation rate of 96.17% can be obtained. In contrast, when industrial magnesium oxide slurry is used as the precipitant, the product purity is 32.07% and the precipitation rate is 90.17%, both of which are significantly lower than those achieved in the active magnesium oxide system. The mixed rare earth oxides from the active magnesium oxide system exhibit distinct diffraction peaks for Y₂O₃ and Dy₂O₃. Furthermore, the crystallinity of the products is superior to that of the industrial magnesium oxide system, characterized by a dense and smooth surface, clear contours, and uniform particles. The research results can provide new theoretical and technical support for the green chemical extraction of ionic rare earth ores.

Due to the characteristics of low grade and fine disseminated particle size, lean hematite is prone to overgrinding in grinding operations, resulting in a large number of fine-grained minerals. Due to the small particle size and large specific surface area, such fine-grained minerals are prone to coverage and surface adsorption competition effects during the flotation process, which significantly weakens the selective adsorption capacity of flotation reagents. Aiming at the problem of selective inhibition in the separation process of fine-grained hematite, a new K⁺ starch inhibitor was developed. Based on the flotation tests of pure minerals of quartz and hematite, combined with contact angle, Zeta potential, Fourier transform infrared spectroscopy and scanning electron microscopy (SEM)-EDS analysis, the inhibition mechanism of new K⁺ starch on fine-grained hematite was systematically revealed. The results showed that when the dosage of K⁺ starch was 150 mg·L^-1, the dosage of activator CaO was 100 mg·L^-1, and the dosage of collector sodium oleate was 200 mg·L^-1, the recovery rate of quartz was 83.5%, which was 4.00 percentage points higher than that of traditional corn starch, while the recovery rate of hematite decreased to 15.85%. In the flotation of mixed magnetic concentrate, the concentrate grade and recovery rate obtained under the action of new K⁺starch were 7.28 percentage points and 5.30 percentage points higher than those of corn starch, respectively. The mechanism analysis showed that K⁺ starch combined with O^2- to form K—O^- bond when K⁺ starch adsorbed onto hematite surface, which reduced the contact angle of hematite surface to 22.31° and formed a hydrophilic film, thus realizing the selective inhibition of hematite. The research results provided the design concept and theoretical basis of new environmentally friendly inhibitors for the efficient separation of fine-grained hematite.

Ilmenite and titanaugite have similar physicochemical properties, and their flotation separation is difficult to achieve. Through flotation tests, Zeta potential measurements and adsorption capacity tests, the adsorption mode and action mechanism of naphthyl hydroxamic acid on the surfaces of ilmenite and titanaugite were investigated, and the key factors affecting flotation performance were clarified. The results show that the adsorption capacity of naphthyl hydroxamic acid on ilmenite is significantly higher than that on titanaugite, and its influence on the surface potential of ilmenite is greater than that on titanaugite. Such adsorption differences increase the flotation difference between ilmenite and titanaugite. The results of actual ore flotation tests show that when naphthyl hydroxamic acid is used as the collector for ilmenite, a titanium concentrate with TiO₂ grade of 47.26% and recovery rate of 80.60% can be obtained in the closed-circuit flotation test, achieving the flotation separation of ilmenite and titanaugite. The research results can provide theoretical support for the development of novel flotation reagents for ilmenite and the optimization of titanium ore flotation processes.

To address the comprehensive utilization of low-grade associated tungsten-fluorite resources in skarn-type copper-polymetallic tailings in southeastern Yunnan, based on an analysis of mineral liberation (≥94%) and identification of mineral forms (85.39% scheelite), a three-stage serial process consisting of "room-temperature mixed flotation of black and white tungsten ores, heated concentration and fluorite flotation" was proposed. At room-temperature, the pulp was adjusted using Na₂CO₃ and Na₂SiO₃. In the heating concentration stage, separation was enhanced at 90 ℃ using NaOH as the adjusting agent. For fluorite flotation, a combination of modified oleic acid GY4 and acidified water glass was used. The results show that the closed-circuit test produces a tungsten concentrate with a WO₃ grade of 62.17% and a recovery rate of 81.30%, as well as a fluorite concentrate with a CaF₂ grade of 96.13% and a recovery rate of 89.47%. Compared with traditional processes, the new method increases tungsten recovery by nearly 4 percentage points and raises the CaF₂ grade of fluorite concentrate by 2.75 percentage points. Preliminary estimates indicate that this initiative could generate at least 550 million yuan in economic benefits annually and reduce tailings discharge by approximately 151 900 t/a. The research findings can provide technical support for the efficient utilization of low-grade associated tungsten-fluorite tailings.

To address the problems of high content of carbonate gangue, high oxidation rate, and severe mudding of lead-zinc oxide ore in Xinjiang, a detailed experimental study on mineral processing technology was carried out. The primary metallic elements in the ore that are of value for mineral processing and recovery are lead and zinc, with concentrations of 6.90% and 6.06%, respectively. Lead is present in lead oxide at a rate of 81.30%, and zinc is present in zinc oxide at a rate of 95.04%. By employing a process flow consisting of lead-oxygen-sulfur mixed flotation, flotation desliming and zinc oxide flotation, and using a compound phosphate that effectively suppresses carbonate gangue minerals, the process successfully prevented the flotation of carbonate gangue minerals, ensured the selectivity of the flotation process, and improved the grade of the lead-zinc concentrate. Through full closed-circuit process test, indicators of 50.32% lead grade, 3.76% zinc grade, and 80.84% lead recovery rate were achieved for the lead concentrate, while the zinc concentrate from the lead-zinc oxide ore exhibited a zinc grade of 35.73% with a lead grade of 4.21% and a zinc recovery rate of 75.62%, achieving efficient flotation recovery of this lead-zinc oxide ore.

To solve the problem of excessive drying shrinkage in alkali-activated materials (AAM), by introducing a CaSO₄-MgO composite expansion agent (CM) to regulate the drying shrinkage behavior of alkali-activated copper slag-ground granulated blastfurnace slag mortar (CS-AAM), the influence of the mass ratio of CaSO₄ to MgO in CM on the workability, hydration process, microstructure evolution, and macroscopic mechanical properties of CS-AAM was systematically investigated, along with the synergistic shrinkage reduction mechanism of CM. The results indicate that adjusting the mass ratio of CaSO₄ to MgO in CM can effectively control the fluidity and setting time of CS-AAM paste. When the mass ratio of CaSO₄ to MgO is 2∶1, the 28-day compressive strength reaches its peak at 74.1 MPa, representing a 4.4% increase compared to the control group, while the 180-day drying shrinkage rate decreases by 40.9%. Microscopically, the total porosity is reduced, resulting in the most compact structure. As the proportion of CaSO₄ decreases, the amount of ettringite formation decreases, while the formation of brucite increases accordingly. Therefore, by adjusting the mass ratio of CaSO₄ to MgO within the range of 3∶0 to 1∶2 can achieve the optimal comprehensive performance of CS-AAM.

Based on the ecological-technical-economic synergy path, the super-efficiency SBM model combined with the GML index method was used to accurately measure the green total factor productivity in Xinjiang, and systematically evaluate the green development level of Xinjiang mining industry cluster. The results show that the green total factor productivity of mining industry in Xinjiang is lower than the national average, and the lack of technological innovation ability is an important factor restricting the development of mining industry in the region. Through the method of location entropy, the degree of industrial agglomeration of mineral resources in Xinjiang is quantitatively analyzed, and finds that it presents the characteristics of "high agglomeration, low green and weak chain", and there is a phenomenon of "virtual fat" in the cluster. With the help of vector autoregressive model, the dynamic relationship between industrial agglomeration degree, green development level and regional economic growth is empirically analyzed. Among them, the green development level has a significant impact on the agglomeration degree of mining clusters. The synergy effect of green development level and industrial agglomeration degree is the core driving force of sustainable economic development, forming a positive feedback mechanism of "green technology-industrial agglomeration-economic efficiency". Based on this, it is proposed to build a "four-in-one" green development system with "ecological value-added, technological empowerment, network synergy and structural optimization" as the core, so as to provide practical countermeasures for the green and high-quality development of mining clusters in ecologically fragile areas.

Safe production is a fundamental cornerstone of the intelligent transformation of mines. To enhance the effectiveness of corporate safety management and effectively reduce the probability of production safety accidents, by introducing role overload, leader identification, work-family facilitation, and work-family conflict as mediating variables, a dual chain mediation model was constructed based on the work-family resources model. A questionnaire survey was conducted to collect 502 valid samples, and empirical analysis was employed to test the hypotheses of the theoretical model. The research results show that self-sacrificial leadership exerts a significant direct inhibitory effect on miners'unsafe behaviors. On one hand, self-sacrificial leadership significantly and negatively inhibits miners' unsafe behaviors indirectly through the chain mediation of leader identification and work-family facilitation. On the other hand, it significantly and positively promotes miners'unsafe behaviors indirectly through the chain mediation of role overload and work-family conflict. Mining enterprise managers should attach importance to the work-family balance of employees and dynamically optimize management strategies and leadership styles to mitigate the risk of safety production accidents.