To reveal the mechanical response law of filling body in deep stope under high ground stress and mining disturbance, the stope of the eighth middle section of Jiaojia Gold Mine was selected as the research object. The stress and deformation data of filling body in different mining stages were obtained by setting pressure cells and settlement sensor. The three-dimensional numerical model of filling body in deep stope was established, and the stress redistribution and deformation evolution law of filling body under multi-layer mining conditions were obtained. The results show that the stress of the filling body fluctuates periodically in the process of mining disturbance. The maximum stress fluctuation in the blasting stage is about 0.02 MPa, and the filling body is mainly elastic strain. During the mining process, the stress of the internal measuring points of the filling body is generally higher than that of the peripheral measuring points, and the vertical stress increases the most. The numerical simulation results show that the interlayer stress transfer characteristics are obvious, and the overall layer-by-layer transfer law from top to bottom is presented. The deformation of the filling body is relatively concentrated and large in the early stage of bearing, and tends to be stable in the later stage. The research results can provide theoretical basis and technical reference for the design of filling body and stability control of stope in deep gold mine.

Blasting damage of surrounding rock is recognized as one of the key factors inducing roadway instability. For the roadways in Jinfeng Gold Mine with a burial depth of over 800 m, a numerical model of full-section blasting excavation was established by means of ANSYS/LS-DYNA, and five rounds of simulation calculations for full-section blasting excavation were carried out. Four typical positions were selected on the roadway section to analyze the cumulative damage effect of multiple blasting events on the surrounding rock. Based on the distribution characteristics of surrounding rock damage, a support method consisting of surrounding rock grouting+long anchor bolts+metal mesh+shotcrete was proposed, and its field application was carried out. The results show that in a single full-section blasting excavation, the blasting vibration from the first two blasting stages causes the expansion of the surrounding rock damage zone, which in turn leads to an accelerated increase in the displacement and damage of the surrounding rock during the last two blasting stages. During multiple full-section blasting excavations, existing damage zones invade the rock mass to be excavated in subsequent blasting operations. The new and existing damage zones connect and coalesce, and their expansion is accelerated, with the scope of the new damage zones increasing by approximately 20% compared with that of the previous blasting round. After the optimization of the support scheme, the reduction rates of convergence displacement of the roadway roof and floor and its two sidewalls reach 41.37% and 42.03% respectively. Anchor pull-out tests indicate that the anchor displacement of the new support scheme is reduced by 37.2% compared with that of the original support scheme, and the anchor rebound coefficient is significantly improved. This study can provide a reference for the calculation of surrounding rock damage and support design in excavation blasting of deep high-stress roadways.

Among the rock mass weakening technology, gas fracturing is more likely to form complex fracture networks compared with hydraulic fracturing. In order to study the fracture propagation mechanism of gas fracturing in the field of directional fracturing technology, laboratory physical experiments and numerical simulation studies on directional gas fracturing based on the radial guide groove technology were carried out. A preparation method of radial guide groove was proposed, a special sealing fixture was designed to simulate the principle of packer, and the acoustic emission device was used to monitor the gas fracturing process in real time. The experimental results show that the radial guide groove can obviously change the propagation direction of gas fracturing fractures within a certain scale, and the fracture initiation pressure is reduced by about 30% compared with that without guide groove. Under the dynamic loading method of gas fracturing, a unique fracture network of primary fracture and secondary micro-fracture appears, and the fracture width increases by 2-3 times compared with the quasi-static loading method. On this basis, LS-DYNA was used to simulate the dynamic dynamics of transient gas fracturing with or without guide groove. Indicators such as effective plastic strain and von mises stress of the models with and without radial guide grooves were compared and analyzed, and the simulation results are consistent with the laboratory experimental results. The research results can promote the development of directional fracturing technology and rock mass weakening methods for deep hard rocks, and provide technical support for the engineering application of directional gas fracturing technology.

In view of the following mining technical challenges in underground mine operations: some stopes are laid out within the broken oxidation zone, giving rise to roof caving and sidewall collapse during production, in addition, ore caving trenches are reserved at the bottom of sublevel medium-deep hole stopes to facilitate ore drawing, which results in the failure of effective recovery of the triangular ore pillars at the stope bottom after mining completion due to the poor quality of backfill materials, thus causing enormous waste of mineral resources. A polymetallic mine was selected as the research object, through field investigation, theoretical analysis and reference to the experience of similar mines, a combined support scheme of shotcrete-bolt-mesh with long anchor cable grouting was proposed to pre-reinforce the roof of the stope to ensure the safe mining of ore in the range of broken oxidation zone. Meanwhile, the medium-deep hole blasting technology was optimized, and the goal of non-trench simultaneous row recovery of bottom pillars was achieved by supplementing short holes. The industrial test results show that after the adoption of the optimized scheme of "pre-controlled roof reinforcement + supplementary short-hole simultaneous row recovery of bottom pillars", the stope roof stability and ore resource recovery rate are significantly improved, the comprehensive production capacity of stopes increases by 21.54% compared with the original scheme, and the loss rate and dilution rate are reduced to 8%, which can be popularized and applied in the underground production area.

A certain iron mine has been using the non-pillar sublevel caving mining method since the start of its operation. Due to severe surface subsidence and high dilution and loss rates of ore, the mine plans to use the filling mining method for the extraction of deep ore bodies. Considering the stability of the ore rock, three filling mining schemes were proposed for areas with poor surrounding rock stability, namely the sublevel filling mining method with pre-controlled roof and rib protection, the upward bench approach filling mining method with pre-controlled roof, as well as the combined mining method of downward approach and upward medium-length hole. After comprehensive comparison of the technical and economic indicators of different schemes and the advantages and disadvantages of each scheme, the combined mining method of downward approach and upward medium-length hole was finally adopted for extracting ore bodies in the unstable deep areas of the mine. Under the condition of fixed mining level height and stope span, numerical simulation was used to optimize the sublevel height. Based on the mine's production capacity requirements, the optimal sublevel height was determined to be 20 meters through optimization analysis. In the mine, the optimized mining method was applied to extract a total of 324 000 tons of hard-to-mine iron ore, generating 69.3 million yuan in revenue and 7.7 million yuan in profit for the mine.

Aiming at the problems of limited mining process and reduced production capacity of deep filling mining method caused by the change of geological conditions in a copper-nickel mine, the process optimization, production capacity check and capacity transition scheme of downward drift filling mining method were studied. Combined with the technical conditions of mining and the current situation of mining methods, in order to realize the continuous and efficient production of downward drift filling method as the optimization research goal, three mining methods were proposed, including downward drift stoping and filling along the strike, downward drift stoping and filling perpendicular to the strike and downward drift stoping and filling obliquely to the strike. Through the comprehensive comparative analysis of the advantages and disadvantages of each scheme and the technical and economic indicators, it is determined that the scheme of downward drift stoping and filling along the strike is the best scheme. The research proposed a capacity calculation method under the condition of continuous mining in the panel. Combined with the occurrence characteristics of the ore body in the middle section of the mine, the panel was divided into three categories, and the production capacity was calculated respectively. On this basis, the calculation of the production capacity of the section was completed, and the capacity transition scheme of the new and old mining processes was formulated. The work deployment of the transition period was clarified. The results show that the optimized filling mining method is technically feasible, safe and efficient, and the capacity transition scheme is operable, which can provide technical support for the mining production and productivity transition of the mine.

Taking the mining area of Tongkeng Mine transition from caving method to filling method as the research object, the thickness of vertical isolation pillar and horizontal isolation pillar calculated by Bieniawski pillar strength formula and K. B. Rupeneyt theory should be less than 9.0 m and 9.36 m, respectively. A three-dimensional fine ore body mining model was established based on FLAC3D, and the influence of the entire mining process on stope stability under different thicknesses of isolation pillar was analyzed. The numerical simulation results show that, when the thickness of vertical isolation pillar is 10 m, the vertical displacement of the stope is less than 0.1 m, the maximum principal stress is 50 MPa, the minimum principal stress is 7.5 MPa, and the safety factor is greater than 8.0.When the thickness of vertical isolation pillar is 8 m, the displacement around the stope increases obviously, the plastic failure zone scope increases obviously, and the safety factor decreases slightly. Therefore, it is recommended that the thickness of the vertical isolated pillar in the mining area of the caving method to the filling method in Tongkeng Mine is 10 m.

Taking the graded tailings backfill of the Shishudi Gold Mine as the research object, the physical and chemical properties of graded tailings and industrial solid waste were analyzed. Using slag powder, steel slag powder and F-gypsum as the main raw materials, and sodium hydroxide, sodium silicate and aluminum sulfate as composite activators, low-carbon solid waste cementitious materials were prepared. Through the mixture design model in response surface methodology, the influence of different mass ratios of components on compressive strength was analyzed, the reliability of the model was assessed, and the optimal proportion of low-carbon solid waste cementitious materials was determined as slag powder∶steel slag∶F-gypsum∶activator=70.69∶10.52∶18.79∶5. Then, XRD, SEM-EDS, and hydration heat analysis were employed to examine the phase composition, microstructure, and hydration kinetics of the low-carbon solid waste cementitious materials. The results indicate that the hydration products of the low-carbon solid waste cementitious materials primarily consist of C-S-H gel, ettringite, and calcite, with the hydration heat release rate and total heat release being reduced by over 30% compared to cement. Pilot-scale tests demonstrate that replacing cement with low-carbon solid waste cementitious materials for gold tailings backfill under the same technical specifications can save more than 50% of cementitious materials, increase tailings utilization by over 10%, reduce backfill costs by over 30%, and cut carbon emissions by 90%, achieving favorable economic and social benefits.

The composite filling structure with strong-weak combination formed by the two-step filling mining bears the roof load jointly, and its overall creep characteristics directly affect the long-term stability of the filling stope. Uniaxial step-loading creep tests were carried out to analyze the influence of different combinations of strong and weak media on the creep characteristics of composite filling specimens. On this basis, considering the time-dependent degradation effect of material mechanical properties and the characteristics of the accelerated creep stage, an improved Nishihara model capable of characterizing the creep characteristics of the composite filling structure was established. The study shows that the strong media has a more significant impact on the overall creep characteristics of the composite specimens. As the strength of the strong media increases from 23.60 MPa to 33.80 MPa, the elastic modulus increases from 1.85 GPa to 2.18 GPa, and the axial creep increments under the first three stress levels decrease by 59.72%, 57.35%, and 55.08%, respectively. The instantaneous creep rates decrease by 31.55%, 21.46%, and 23.14%, respectively. The transverse strain difference between the strong-weak media increases from 260 με, 368 με, and 524 με to 685 με, 895 με, and 1 032 με, respectively. The overall creep failure mode of the specimens transforms from shear failure to compressive splitting failure. The improved Nishihara model achieves a fitting accuracy exceeding 0.93 for the experimental data, effectively simulating the entire creep process of the composite filling structure.

At present, pre-splitting blasting technology is not used in the construction of bench slope in an open-pit in Yunnan, which leads to unsatisfactory slope forming effect. In order to improve the forming quality and design coincidence rate of the bench slope with small-dip in the stope, the pre-splitting blasting test was carried out for the 55° gentle slope. Using the control variable method, the field control test was carried out with the pre-splitting hole spacing, line charge density and hole diameter as variables. The test results show that it is feasible to use the pre-splitting blasting method to realize the forming of the gentle bench slope with a small-dip of 55° in the blasting area. The quality of the slope is significantly improved after blasting, and the design coincidence rate is high. When the hole spacing is 1.3 m, the hole diameter is 115 mm, and the linear charge density is 0.8 kg/m, the test area achieves the best blasting effect, and the residual hole mark rate of the blast hole is about 80%.

In order to study the dynamic response and stability of goaf group under blasting stress disturbance, based on the structural characteristics of goaf group and its interaction with surrounding rock, the dynamic response model of goaf group was constructed, the dynamic response analysis method was created, the dynamic instability criterion was put forward, and its stability was judged. An underground limestone mine was selected as the object for calculation and analysis, which was compared with the results of numerical simulation and field monitoring. The influence of different blasting frequency, span-height ratio of goaf and height-width ratio of pillar on the dynamic response of goaf group was studied. The results show that under the disturbance of blasting stress, the calculation results of dynamic response analysis method are consistent with those of numerical simulation and field monitoring. The velocity and displacement response of the goaf group are mainly concentrated in the x and y directions. The blasting frequency significantly affects the velocity and displacement response of the goaf group, and the relationship curve between the two types of peak and frequency is " single peak ". The peak velocity increases first and then decreases with the increase of the span-height ratio of goaf, the inflection points of the peak velocity curves in the x and y directions are 0.8 and 0.6, respectively. The peak displacement increases linearly with the increase of the span-height ratio of goaf, and the linear change slopes in the x and y directions are 0.926 and 0.670, respectively. The peak values of velocity and displacement increase slowly with the increase of height-width ratio of pillar, which has a weak influence on the stability of goaf group. The research results can provide a new method for the dynamic response of goaf group.

In order to solve the problem of water inrush and instability of stope caused by a large amount of fissure water in the water-rich fault fracture zone, taking the stope in the northern area of Zhongguan Iron Mine as the background, the water pressure monitoring tests was carried out. The sensitivity of stope stability to water pressure change was explored by FLAC3D, and the water pressure gradient with obvious change was obtained. Then, a numerical model of "water pressure-waterproof layer thickness" was established to explore the control effect of different water pressure values and waterproof layer thicknesses on stope stability. The stability and variation rules were analyzed with the distribution of roof stress, displacement and plastic zone as indicators, and the relationship between water pressure and waterproof layer thickness was obtained. The results show that the ore body in the northern area of Zhongguan Iron Mine is a typical water-rich deposit, and the water pressure is between 0.1 MPa and 2.0 MPa. When the water pressure is greater than 1.0 MPa, the influence of water pressure on the roof stability is significant. Based on the comprehensive analysis of the variation trends of stress, displacement and plastic zone, the following conclusions are drawn: when the water pressure is 0.1 MPa, the the waterproof layer thickness should not be less than 1.8 m; when the water pressure is 0.5 MPa, the waterproof layer thickness should not be less than 3 m; when the water pressure is 1.0 MPa, the waterproof layer thickness should not be less than 4 m; when the water pressure is 1.5 MPa, the waterproof layer thickness should not be less than 5.6 m; when the water pressure is 2.0 MPa, the waterproof layer thickness should not be less than 7.1 m. The simulation results provide theoretical support for determining the waterproof layer thickness corresponding to different water pressure values in this ore body.

To investigate the roof fracture characteristics and mine pressure distribution patterns in ultra-long working faces (with a strike length ≥ 300 m), thereby effectively guiding roof control, the 132205 ultra-long fully mechanized working face in Xiaobaodang Coal Mine was taken as the research background. Combining theoretical analysis, numerical simulation, and field measurements, a zonal fracture mechanism of "central preferential fracture-migration toward both sides" which was formed under the coupling effect of advanced mining-induced fractures and primary fractures was revealed. The evolution process involves three stages, namely fracture in the central peak zone, stress migration in the non-peak zone, and instability in the side peak zones. Based on FLAC3D numerical simulation, the influence of working face length on mine pressure manifestation was elucidated as follows. When the length increases from 250 m to 450 m, roof subsidence grows several-fold, the initial pressure step distance decreases to 75 m, and the mine pressure distribution pattern shifts from an "arch-shaped" single peak to an "M-shaped" triple peak. Field-measured data from hydraulic supports validates the reliability of the simulation results. An innovative zonal coordinated rack-moving scheme of hydraulic support regulation was proposed, improving support resistance uniformity through differentiated strategies of grouped rack-moving mode in high-stress zones and stand-alone rack-moving mode in low-stress zones, holding significant engineering value for promoting large-scale development of shallow-buried coal seams in western China.

Landslide is an extremely destructive natural disaster. Accurate assessment of the ecological restoration effect in mine landslide treatment areas is of great significance for ensuring the safety and ecological stability of the surrounding areas. Airborne Light Detection and Ranging (LiDAR) data were used to construct Digital Elevation Model, Digital Surface Model, and normalized Digital Surface Model for terrain feature extraction. Combined with visible difference vegetation index and texture information features, the Pianqiaogou landslide treatment area in Du'erping Coal Mine was selected as the study area to perform ground object information extraction and classification using support vector machine optimized by particle swarm optimization algorithm. The results show that this method has a good classification performance, with the overall classification accuracy reaching 94.12%, the Kappa coefficient 84.19% and the F₁-score 93.52%. It is superior to the other two traditional classification methods. In addition, the Shannon Diversity Index of the treatment area reaches 0.958 4, which verifies the effectiveness of the mine landslide control measures, and provides ideas for the application of LiDAR in mine landslide treatment areas.

Aiming at the problems of water-induced cracking and insufficient durability of steel fiber reinforced concrete support in the roadway of a certain iron mine in Yunnan, based on the three-factor and three-level orthogonal test design, water absorption rate and sulfate erosion resistance tests were systematically carried out, and the influence laws of water-cement ratio (0.42, 0.45, 0.47), steel fiber content (2%, 3%, 4%) and waterproofing agent content (0.10, 0.12, 0.14) on water absorption rate and sulfate erosion resistance performance were quantitatively analyzed to optimize the water durability of the materials, and the optimal proportion was applied to the actual roadway support of the certain iron mine in Yunnan for construction verification. The results show that the water absorption rate of steel fiber reinforced concrete under various optimized proportions is relatively low, and the content of waterproofing agent has the most significant effect on water absorption rate (with a range of 1.73%). When the content of waterproofing agent is 0.14, the water absorption rate decreases to 4.69%. In the sulfate erosion resistance tests, the mass loss ratios of specimens are all negative (-0.35%--0.14%), the compressive strength increases with the increase in the number of cyclic erosion times, and the content of waterproofing agent has the most significant effect on compressive strength (with a range of 22.7 MPa). Proportion 2 (with a water-cement ratio of 0.42, 3% steel fiber content and 0.14 waterproofing agent content) exhibits the best comprehensive performance, with a water absorption rate of 4.54%. Its compressive strength increases from the initial 70.6 MPa to 83.1 MPa, with an increase of 17.6%. Field application results show that after support with Proportion 2, the displacement of two sides of the roadway stabilizes at 25 mm, with no significant leakage on the surface, which verifies the feasibility of the optimized proportion.

To accurately evaluate the roof water inrush risk of deep roadways and make up for the low credibility of traditional evaluation methods caused by index redundancy and subjective weighting, a comprehensive calculation method coupling with principal component analysis (PCA) and entropy method was proposed. PCA was used to reduce the dimension of multi-source indexes to eliminate information overlap. After key principal components were extracted, the weight of each principal component was quantified. The entropy method was introduced to achieve the objective calculation of comprehensive evaluation indexes. Combined with the sample input datasets of each index, the evaluation model of coal seam roof water inrush was constructed with the logical framework of "principal component extraction-comprehensive index calculation-model comparison and verification-dynamic prevention and control". The results show that the fault water conductivity coefficient is the main controlling factor affecting the roof water inrush of the working face, and the permeability coefficient is the second most important. Based on the high fitting characteristics of the comprehensive index calculated by the PCA-entropy method and the on-site water seepage data, five categories of water-rich risk levels have been divided. It is determined that the area 518-678 m away from the open-off cut of the 1315 working face is in the extremely high-risk area, and the area 0-425 m away is in the high-risk area. According to the characteristics of roof water inrush in different areas, the technical path of "partition-based prevention and control-three-dimensional interception-drainage optimization" was proposed. The research results improve the classification and identification system of roof water inrush risk levels, and provide a new method for the safe exploitation of deep resources.

During the mining process of underground ore bodies, the collapse of goaf can disrupt the stress balance of rock strata, leading to geological disasters and endangering surface facilities. In order to improve the accuracy of surface subsidence prediction in mines without actual monitoring data during the unmined stage, as well as to ensure personnel safety and mining production, a method combining neural networks and transfer learning for underground mining surface subsidence prediction was proposed. The method combines the advantages of long-short-term memory neural networks to accurately extract time series features and deep convolutional neural networks to extract local features of data, improving the accuracy of the prediction model. According to the mining design of Zhonggangou vanadium titanium magnetite, the prediction model was used to predict the surface subsidence under different mining schedules. The results show that with the increase of ore output, the mean square error of each segment is less than 0.4.The proposed model shows a high accuracy in surface subsidence prediction under different mining schedules. This method can provide a reference for surface subsidence prediction and safety monitoring of similar mines.

Aiming at the limitations of the current debris flow source detection algorithm, a YOLOv5s-GCE model was proposed. This model introduces CBAM attention mechanism, Ghost convolution and EIOU bounding box loss function to improve its identification accuracy and efficiency. In order to verify the detection effect of YOLOv5s-GCE model, it was compared with YOLOv4 and YOLOv5s models. The results show that the average accuracy of the YOLOv5s-GCE model is 95.4%, which is 2.5 and 8.6 percentage points higher than that of the YOLOv4 and YOLOv5s models, respectively. The detection accuracy of YOLOv5s-GCE model for debris flow source is as high as 96%, and the detection effect is better. The particle flow numerical simulation method was used to study the migration law of debris flow. The simulation results show that the front end of the source body is destroyed and migrated in the initial stage, and the infiltration of water particles leads to the increase of porosity and structural instability of the source body. The mid-section of the source body is subjected to compression from the rear end and restraint from the front end, leading to a significant reduction in porosity, structural densification and the occurrence of localized bulging. In the later stage of migration, a large number of material sources accumulated at the gully mouth. The threat of debris flow to downstream construction facilities is significant, and the soil on the left side of the mid-section of the source area is the most threatening in extreme weather. The research results are of great significance to the prevention and control of slag-type debris flow.

To investigate the effect of chemical solution corrosion on the dynamic impact compression mechanical properties of sandstone, red sandstone accelerated by distilled water and HCl solution with pH of 5 and 3 were used as the research objects. Dynamic compression tests were conducted under five different impact pressures to explore the influence of chemical solution corrosion on the dynamic mechanical parameters, crushing energy consumption, and failure mode of sandstone. The corrosion process and degradation mechanism of sandstone by chemical solutions were revealed using XRD and SEM, and the variation of micro fractal dimension before and after chemical solution corrosion was quantitatively characterized by box-counting method. The results indicate that in acidic environments, muscovite and plagioclase in sandstone will transform into quartz and soft kaolinite, and the cement will be dissolved. The contact mode among particles will change, resulting in an increase in the fractal dimension and damage rate of sandstone microstructure with the increase of solution acidity. Under the action of acidic solution, the stiffness of mineral particles decreases, the structure is loose, and the mechanical properties deteriorate. Taking the strain rate of 58.06 s^-1 as an example, as the acidity of the solution increases, the peak dynamic stress decreases by 17.27%, 39.83% and 49.63%, respectively, and the dynamic peak strain increases by 13.04%, 31.30% and 38.26%, respectively. After corrosion, the macroscopic fragmentation of sandstone intensifies, the energy consumption ratio decreases, the fractal dimension increases, and the failure mode changes from tension to shear. This research system reveals the mechanism of the influence of chemical corrosion on the dynamic mechanical behavior of sandstone, providing a reference for the stability assessment of rock engineering in acidic environments.

Accurate measurement of the uniaxial compressive strength of rock is the foundation of support design and rock mass stability analysis. By conducting indoor drilling tests on rocks with different strengths, the energy conversion and dissipation during the drilling process were analyzed, and the relationship between various forms of energy and rock strength in the process was studied. The results show that among the mechanical energy input by the drill bit, the torque work accounts for more than 95%, while the drilling pressure work accounts for no more than 5%. The energy input by the drill bit is mainly converted into the surface energy of drill cuttings, with an average conversion rate of 95.6%, and the average conversion rate of thermal energy is 4.2%. There is an obvious linear relationship between the net specific drilling work and the uniaxial compressive strength of mortar specimens with different strengths. The relational equation between the net specific drilling work and strength is obtained by fitting. This equation has been verified by using the drilling test results of concrete, sandstone and granite, with a maximum discrepancy rate of 5.07%. Relational equations between the surface energy of drill cuttings, thermal energy, acoustic energy and rock strength were obtained by fitting, and the relationships between various forms of energy and rock strength can be verified with each other. The drilling measurement method for rock strength based on drilling energy has good applicability.

Aiming at the erosion damage of backfill materials caused by sulfate solution erosion and dry-wet cycling, dry-wet cycling tests of backfill specimens were carried out in tap water and sodium sulfate solutions with mass concentrations of 3%, 6% and 9%, respectively. Meanwhile, the microstructures of the backfill were observed by scanning electron microscopy (SEM). The damage evolution law and erosion damage mechanism of the backfill were studied. The test results show that after 120 times of dry-wet cycling, the mass of the backfill decreases by only 0.19% in the tap water environment. However, the mass losses under the erosion of sodium sulfate solutions with mass concentrations of 3%, 6% and 9% are 0.73%, 1.52% and 3.64% respectively, and the mass reduction amplitude increases in a gradient manner with the increase of solution concentration. Under the condition of the same sodium sulfate solution concentration, the uniaxial compressive strength of the backfill specimens shows a gradual decreasing trend with the increase of the times of dry-wet cycling. After undergoing 30 times of dry-wet cycling of erosion in a 3% sodium sulfate solution, the uniaxial compressive strength of the backfill increases from 14.36 MPa to 14.85 MPa. The free sulfate ions in the sodium sulfate solution enter the backfill and chemically react to form ettringite. A small amount of ettringite is filled into the internal pores of the backfill, which enhances the mechanical properties of the backfill to a certain extent. However, with the increase of ettringite, the density of microscopic defects in the backfill increases, resulting in a gradual decline in its strength.

To investigate the characteristics of heavy metal pollution and its spatial distribution patterns in the soil around the Qidashan iron mine, three types of single pollution sources (open-pit mine, waste rock dump, and tailings pond) and their multi-pollution source areas were selected as the study objects. Soil samples were systematically collected, and the concentrations of four heavy metals (Ni, Cr, Zn, Cu) and physical and chemical properties of soil were measured. A spatial distribution model was constructed by using the inverse distance weighting interpolation method, and correlation analysis was conducted to explore the migration patterns of soil pollutants under both single and multi-pollution source conditions. The results show that the concentrations of all four heavy metals generally exceed the background values of Liaoning Province, among them, Ni pollution is the most prominent. Horizontally, the heavy metal contents in the soil around single pollution sources decrease with increasing distance, while the multi-pollution source composite area exhibits a center-high distribution pattern. Vertically, heavy metals show overall enrichment in the surface layer, but in some areas, influenced by rainfall leaching and soil adsorption, a "low at surface layer-high at middle layer-low at deep layer" distribution phenomenon has been observed. Correlation analysis indicates that the spatial distribution of heavy metals is jointly influenced by pollution source types, distance, and physical and chemical properties of soil such as pH, organic matter content, and cation exchange capacity. This study can provide a scientific basis for the prevention, control, and ecological remediation of soil pollution in mining areas.

To scientifically evaluate the effectiveness of ecological restoration in open-pit mining areas, a comprehensive assessment system comprising five indicators, including vegetation coverage, soil moisture, soil and water conservation, air quality and landscape ecological risk, was established from both macro and micro perspectives, based on multi-source data such as remote sensing, precipitation, and soil information. Taking the Quzhai mining area for cement in Luquan, Shijiazhuang as the experimental area, quantitative assessment of ecological restoration status from 2021 to 2023 was carried out. The results show that from 2021 to 2023, the overall vegetation coverage in the mining area increases, soil moisture improves, soil erosion decreases, air quality improves, and the proportion of areas with "good" comprehensive restoration effects increases from 47.38% to 57.74%, reflecting the overall effectiveness of restoration measures. However, the proportion of "relatively poor" and "poor" level areas has also increases, mainly due to ecological risks caused by local landscape fragmentation and land use type conversion. Therefore, it is recommended to implement refined management for high-risk areas, as well as optimize vegetation configuration and landscape connectivity, in order to enhance the overall quality and sustainability of ecological restoration in mining areas. The evaluation method constructed in this study can provide a reference for monitoring, assessment, and scientific management of ecological restoration in mining areas.

Biodiversity conservation becomes an increasingly prominent global concern and a central element of sustainable development, integrating biodiversity protection into mining activities is essential for fulfilling corporate social responsibility and enhancing overall competitiveness. China's biodiversity conservation efforts in the mining sector are currently undergoing a transition from being primarily policy-driven to increasingly characterized by technological integration and systematic practice, with an urgent need for further refinement and enhancement of methodological frameworks and implementation pathways. Grounded in the mitigation hierarchy framework, an internationally accepted biodiversity management tool, it systematically sorts out and refines the key biodiversity conservation action paths that need to be focused on in different phases of mines. In the project development phase, comprehensive baseline biodiversity assessments and socio-economic impact evaluations were conducted to inform tailored biodiversity management plans. During the operational phase, effective implementation of management plans was ensured through continuous ecological monitoring and adaptive management. In the transition phase from operation to closure, systematic restoration and rehabilitation efforts were carried out, striving to rebuild stable, self-regulating local ecosystems. At closure, the focus shifted to long-term ecosystem functionality and sustainable land use, supported by closed-loop management and ecological compensation mechanisms to align environmental conservation with regional development. Taking the Ambatovy Nickel and Cobalt Mine in Madagascar as a representative case, the biodiversity conservation practices under the mitigation hierarchy framework was analyzed. The study aims to provide insights for the development of biodiversity-friendly mines across the whole life cycle in China, thereby supporting mining enterprises in achieving high-quality and green development.

In order to reduce the cost of microbially induced carbonate precipitation (MICP), the effects of industrial-grade bovine bone protein peptone dosages, soya peptone dosages, sodium chloride dosages and urea dosages on the microbial quantity OD₆₀₀ value and urease activity of Sporosarcina pasteurii cultured for 16 hours were studied. Response surface methodology was used to optimize the optimal ratio of industrial culture medium. And the microbial quantity OD₆₀₀ value and urease activity of the bacterial solution under the optimal ratio were detected. After the bacterial solution cultured for 16 hours reacting with different concentrations of cementing solution, the amount of calcium carbonate produced by the two reactions was measured, and the calcium carbonate crystals was analyzed using scanning electron microscopy (SEM). The results show that the optimal medium ratio is 25 g/L of bovine bone protein peptone, 7.5 g/L of soya peptone, 5 g/L of industrial sodium chloride, 22.2 g/L of industrial urea, and 1 000 mL of pure water. The OD₆₀₀ value of Sporosarcina pasteurii liquid cultured for 16 hours under this ratio is 1.672, and the urease activity is 0.037 mmol/(L·min), both of which are within the prediction error, indicating feasibility of the results. The content of calcium carbonate generated by cementation under the two media is not much different, and the cementation effect of industrial-grade culture medium bacterial solution is stronger than that of analytical pure culture medium bacterial solution. The research results can provide a low-cost medium ratio scheme for the large-scale engineering application of MICP.

To investigate the synergistic mechanism of uranium tailings reinforced by sodium silicate synergized with Sporosarcina pasteurii, a uranium tailings was taken as the research object. By measuring the OD value and pH of Sporosarcina pasteurii in the environment containing sodium silicate, the effects of sodium silicate solutions with different modulus and different mass fraction on the growth law of Sporosarcina pasteurii were analyzed. Based on the microbial induced carbonate precipitation (MICP) technology, the experiment of uranium tailings column reinforced by sodium silicate synergized with Sporosarcina pasteurii was carried out, and the unconfined uniaxial compressive strength of uranium tailings columns in each group was compared and analyzed. The results show that sodium silicate with an appropriate mass fraction and modulus can significantly improve the unconfined uniaxial compressive strength of uranium tailings columns. The effect of sodium silicate solution with a modulus of 2.3 and a mass fraction of 5% is the best, and the corresponding unconfined uniaxial compressive strength of the uranium tailings column reaches 284 Pa, which is 11.8% higher than that of the single Sporosarcina pasteurii reinforcement group of 254 Pa. The results of X-ray diffraction ( XRD ) show that the precipitates formed in all experimental groups are mainly calcium carbonate crystals. Compared with the single Sporosarcina pasteurii control group, the calcite crystals formed therein have a higher proportion and better crystallization thermodynamic stability. Scanning electron microscopy (SEM) images combined with energy dispersive spectroscopy (EDS) results further confirm that after the addition of sodium silicate solution, more calcium carbonate crystals are formed, the crystal surface are smoother and flatter, and the structure is more compact. The research results provide theoretical guidance for improving the reinforcement technology of uranium tailings reservoir.

To scientifically and reasonably evaluate the level of emergency rescue system construction, 26 indicator factors were selected from four dimensions: pre-emergency prevention, pre-emergency preparation, in-process emergency rescue, and post-recovery and reconstruction. The interval analytic hierarchy process-improved CRITIC method was used to calculate the weight of each indicator factor, and the grey correlation method was used to improve the traditional VIKOR method. A multi-criteria compromise decision-making model for the emergency rescue system of metal mines based on combination weighting-grey VIKOR was proposed. Taking five underground metal mines as the research background, the established model was applied to evaluate the emergency rescue system. The evaluation results were compared with the weighted grey correlation method and weighted TOPSIS method, and the differentiation analysis of emergency rescue system construction was carried out based on the radar chart method. The results show that the evaluation results of the model are reasonable and reliable, with stronger applicability and higher identification, verifying the feasibility of the combination weighting-grey VIKOR model in the evaluation of emergency rescue systems in metal mines.

To meet the regulatory demands of systematization, legalization, scientization, long-cycle operation and democratization for mine ecological security in the context of the new era, a comprehensive regulatory framework based on Nature-based Solutions (NbS) was established through relevant research. This framework is formulated in accordance with 8 design criteria, namely problem objects, design scales, natural attributes of solutions, benefit evaluation, solution feasibility, solution management processes, adaptive management modes and sustainability, and focuses on the ecological security supervision of mines throughout the full life cycle of mining activities, including the stages of mine survey and design, mining operation, and mine closure and maintenance. In response to the risks and challenges faced by mine ecological security in Guangdong Province, such as the contradiction between mine ecological and environmental protection and economic development, the overlap between development space and protection space, and the severe ecological and environmental problems caused by mining development, innovative paths and strategies for mine ecological security supervision in Guangdong Province in the new era are explored from six aspects, including forward-looking layout, source control, nature enhancement, nature coordination, multi-stakeholder governance, and technological innovation. This study aims to provide a scientific basis for mine ecological security supervision in Guangdong Province and even across the whole country.

Aiming at the problems of high cost in manual scheduling and low vehicle utilization rate for trackless rubber-tyred vehicles in underground coal mines, an intelligent scheduling model was established to coordinately optimize transportation efficiency and environmental performance. Firstly, the MT-CVRPTW model integrating hard time windows, cargo taboos and mileage constraints was established. Secondly, a bi-objective optimization model with the objectives of minimizing the total cost and carbon emissions was constructed, and a Parallel Genetic Algorithm-Adaptive Large Neighborhood Search (PGA-ALNS) hybrid optimization framework based on PGA and ALNS was proposed. The results of the simulation experiments show that, through the two-layer collaborative mechanism of the global search of PGA and the dynamic neighborhood optimization of ALNS, combined with the time-sensitive weight strategy and elite retention mechanism, the algorithm keeps the carbon emission cost at the minimum. Compared with the Genetic Algorithm and Simulated Annealing Algorithm, its total transportation cost is reduced by 11.1% and 7.6% respectively, the total distance is reduced by 10.7% and 4.7% respectively, and the solution time is shortened by 40.2% and 36.1% respectively. For the scheduling scheme optimized by the PGA-ALNS algorithm, its average vehicle load rate reaches 94.16%. This method effectively improves the economic efficiency and environmental friendliness of underground transportation, and provides a technical path for the construction of intelligent mines.

Aiming at the problems of uneven illumination, complex background and large difference in structural plane morphology of borehole images, a dual-encoder interactive attention enhanced fusion network ( DISA-FuseNet ) was proposed. Based on the UNet encoder-decoder architecture, the network adopted the dual-encoder structure of Swin Transformer and ResNet50 to capture global context information and local detail features simultaneously. The attention was weighted by the Statistical Aggregation Channel Attention ( SACA ) module to suppress the background noise and irrelevant information of the rock mass. The underlying features were inputted into the Adaptive Hierarchical Enhancement module ( AHE ) after splicing to enhance the network's ability to capture multi-scale structural plane features. Experimental verification was conducted based on the self-constructed borehole structural plane dataset, and DISA-FuseNet was compared with five models, namely UNet, Deeplabv3+, Trans-UNet, DeepCrack and CrackFormer. The results show that DISA-FuseNet outperforms all the other models in terms of mean intersection over union, mean pixel accuracy, recall, precision and F1-score, these indexes are increased by 8.44, 9.51, 8.52, 10.60 and 9.62 percentage points respectively compared with those of the baseline model UNet. Furthermore, a method for structural plane parameter extraction and 3D visualization is proposed, which enables the accurate extraction of structural plane parameters and the construction of an interactive 3D visualization model. The actual engineering case verifies that the method has good effectiveness and engineering applicability.

Aiming at the challenges posed by the spatiotemporal randomness of wind resources in large-scale wind power bases in mining areas to the design of high-power wind turbine generators, based on the measured data of a wind farm in a mining area of Inner Mongolia, the adaptive design and optimization research on the 6.0 MW permanent magnet wind turbine generator was conducted. Based on multi-dimensional wind measurement data mining, the joint probability distribution of wind speed, temperature and duration was quantified, a dynamic load spectrum model reflecting the actual wind conditions was established, and with the objectives of improving electromagnetic characteristics and reducing material costs, the coordinated optimal design of coil size and permanent magnet size was carried out. The electromagnetic scheme was verified by finite element simulation, and the design target of 98% efficiency was achieved. The test results show that the errors between the no-load and load characteristics of the two developed prototypes and the simulation results are all within 3%, which verifies the high accuracy of the model. The temperature rise test reveals the temperature field distribution law of the generator under complex operating conditions, and the thermal management and control strategy is formulated accordingly. The study forms a complete technical chain consisting of "data-driven modeling-multi-objective optimization-simulation verification-prototype testing", which not only provides solutions for specific wind farms, but also offers references for the engineering application of high-power permanent magnet wind turbine generators in large-scale wind power bases.

Chengchao Mining Company adopts the principle flotation flowsheet of bulk flotation followed by separation to recover valuable resources such as copper and sulfur from iron tailings, but the copper recovery rate is relatively low. Therefore, aiming at the bulk flotation concentrate, the effects of factors such as regulators, depressants, collectors and pulp mass concentration on the separation flotation performance of copper and sulfur were studied in detail through tests. The results show that the optimal separation flotation conditions are as follows: pulp mass concentration of 30%, activated carbon dosage of 120 g/t, quicklime dosage of 6 000 g/t, and Z-200 dosage of 30 g/t. Under these flotation conditions, by adopting the process flowsheet of one roughing, two cleanings, one scavenging and sequential return of middle ore, a copper concentrate with a Cu grade of 16.00% and a Cu recovery rate of 54.87% can be obtained. A sulfur concentrate with a sulfur grade of 35.10% and a sulfur recovery rate of 33.57% can be obtained. The copper content of the flotation tailings is 0.013% and the sulfur content is 6.89%, among which the copper content in sulfides is 0.006 3%. 97.97% of the sulfur element exists mainly in sulfates, which indicates that the adopted reagent system and flotation process flowsheet can fully recover copper and sulfur from iron tailings.

Coal flotation tailings, as a low-value product of coal preparation plant, is rich in potential resources such as kaolinite. The coal slime from Malan Coal Preparation Plant was used as an experimental object. The mineral composition and particle size distribution was analyzed, the influences of flotation time and reagent consumption on the recovery of middling coal slime were researched, as well as the influence of structure and operation parameters of hydrocyclone on classification of kaolinite. On this basis, a process experiment of three-stage cyclone classification and flotation combined process was carried out, and the combined process of "three-stage classification and coarse-fine flotation" was proposed to recover kaolinite. The results indicate that the main minerals in the sample are kaolinite and quartz. Under the conditions of 1 500 g/t of collector, 150 g/t of foaming agent, and 5 min of flotation time, the ash content of tail coal can reach 80.11%. Under a certain feeding pressure, the smaller the diameter of the cyclone, the more significant the enrichment effect on kaolinite. The combined process of "three-stage classification and coarse-fine flotation" can obtain kaolinite products with a yield of 20.26% and a grade of 78.88%, and middling coal slime products with a yield of 40.85% and ash content of 33.87%. At the same time, about 38.89% of coarse sand tailings (ash content of 82.45%) can be directly discarded. Research can provide new technological approaches for improving the quality and resource utilization of flotation tailings in coal preparation plants.