Shotcreting technology,a primary method for roadway bolt-shotcrete support,is now widely applied in mine excavation support. Dust is generated during shotcreting operations,including handling,feeding,mixing,and spraying stages,making it one of the main dust sources in mining. For current research on shotcreting dust control technologies,quantitative analysis of literature over the past 50 years was conducted using CiteSpace software. Research hotspots were categorized and statistically analyzed in terms of publication volume, authors, institutions, keyword co-occurrence, clustering, and time zones. Research shows that China′s research on shotcreting technology started relatively late,with its development showing phased characteristics:① Embryonic exploration stage,in the 1970s,breakthroughs were made in the development of shotcrete equipment. Shotcreting technology gradually found application in mine roadways and slope support,but the technology and equipment remained immature. ② Growth and development stage,in the 1980s,wet spraying technology began to be promoted. However,due to insufficient emphasis on safe operation,severe dust hazards and frequent production accidents occurred. ③ Mature growth stage, in the early 21st century,the state introduced clear legislation on work safety and occupational diseases. The dust problem in shotcreting operations thus received sustained attention and research from scholars in the field,driving the development of shotcreting dust control research. After 2010,improving the practicality of shotcreting machines became the focus,with a rapid increase in the number of related publications. ④ Epidemic-induced downturn stage,from 2018 to 2022,the number of publications declined significantly due to the impact of the epidemic and research cycles. However,long-term projections suggest that research in shotcreting dust control still has substantial room for expansion in breadth and depth,with growing attention. Core authors maintain extensive collaborative relationships,while non-core authors are widely distributed and highly independent. Research teams in shotcreting dust control are mainly composed of universities and colleges,with no extensive collaboration formed among institutions across regions. Both authors and institutions in English literature overlap significantly with those in Chinese literature. Domestic scholars focus more on engineering applications,whereas foreign scholars mainly emphasize areas such as the laws of wet concrete pipeline transportation and jet structure characteristics. Keyword evolution indicates that the existing research is moving toward in-depth exploration of optimizing shotcreting equipment and applying shotcrete in new materials and environments,with an increasing number of research directions. On this basis,current challenges in shotcreting dust control research are further discussed,along with future development trends. Key challenges in this field include clarifying dust generation and reduction mechanisms in shotcreting,developing intelligent and precise wet shotcreting technologies,creating portable shotcreting equipment,strengthening vocational training for technical workers,expanding research teams,and enhancing collaborative development and research among industry,academia,research,and application. Future research on mine shotcreting dust control can be deepened through measures such as clarifying dust generation and reduction mechanisms via various experiments and numerical simulations,developing precise dust control schemes by integrating emerging intelligent technologies like artificial intelligence and machine vision,strengthening research on drag reduction in long-distance material pipeline transportation and dust-free jet theory,expanding shotcreting dust prevention applications across multiple fields and industries,and promoting standardization of shotcreting dust prevention and control. 

In response to the defect that ordinary slurry is prone to shrinkage and affects the reinforcement effect,and only provides bonding effect on the supported rock mass,a grouting reinforcement idea of " squeezing first and then bonding" for expansive slurry is proposed. The system research conducted on three parts:the performance of expansive slurry,the mechanical properties of expansive slurry-rock mass composites,and the application test of expansive slurry. Firstly,the volume expansion rate,expansion stress development characteristics,and expansion mechanism of expansive slurry were introduced. The influence of different constraint conditions and stress on its expansion and strength properties was analyzed,and methods for improving the mechanical strength of expansive slurry and regulating the setting time were explored. Secondly,theoretical analysis,experimental research,and other methods were used to study the strength model and shear mechanics mechanism of the slurry-rock composites. Finally,numerical simulations and on-site experiments were used to explore the application effect of expansive slurry in the grouting reinforcement of steep layered rock roadway roof and mortar grouting anchor support,revealing its mechanical mechanism of grouting reinforcement. The results show that:① The expansive slurry has good volume expansion rate and expansion stress,and the maximum volume expansion rate is 36. 96%,20. 22% and 3. 89%,respectively,under different constraints. The uniaxial compressive strength of the sample is 2. 53,8. 82,13. 55 MPa,respectively. The more constraints on the development of slurry expansion,the smaller the volume expansion rate and the higher the strength. ② The shear strength of the slurry-rock mass composite by the grouting reinforcement with expansive slurry and ordinary slurry is 2. 95 MPa and 2. 26 MPa respectively,and the shear strength of the slurry-rock mass composite by the grouting reinforcement with expansive slurry is increased by 30. 53%. ③ The final displacement of steeply inclined stratified rock mass roadway roof by the grouting reinforcement with expansive slurry is lower than that of ordinary slurry. The stress on both sides of the roof is larger during expansive slurry grouting,and the stress on the roof is significantly greater than that after ordinary slurry grouting on the whole. ④ After adding a certain amount of expansive slurry,the mortar can produce 2. 03~ 8. 26 MPa radial expansion stress on the anchor, which is 59. 8% higher than the maximum pulling strength of the ordinary mortar anchor,and has a better anchoring effect. The above research shows that the expansive slurry has a good volume expansion effect,and although the volume expansion is limited in a limited space,resulting in a higher mechanical strength,which can effectively improve the overall compressive and shear strength of the supported rock mass,and has a good test effect in the stope roof with fault and the grouting anchor support. This study can provide good technical reference and theoretical support for the study and application of grouting reinforcement technology of underground geotechnical engineering. 

As a key channel in the downward drift mining,the reasonableness of the structural parameters of the layered roadway is a key factor to ensure operational safety and efficiency. Therefore,in order to achieve the safe and efficient mining of the stope,the structural parameters of the layered roadway in each working area need to be unified and optimized. The simply supported beam model,Winkler model and the field convergence deformation monitoring test method are comprehensively used in this paper. It investigates the influence of the width of layered roadway and the un-roof-contact conditions of filling body on its stability,determining the best theoretical values of the structural parameters of the layered roadway,and verifies the reliability of the theoretical analysis by field test. The results show that the maximum tensile stress of the un-roof-contact height decreases gradually with the decrease of the height and width of the layered roadway,and the safety factor to the height of the un-roofcontact is more sensitive than that of the width. The maximum bending moment of the layered roadway roof appears in the middle of the span,and bending moments still exist at the supporting roof of the deformable foundation of the two sides of the rock, which gradually decreases with the increase of the depth of the side and the height of the roof. The maximum average convergence rate of the layered roadway monitoring surface is 0. 072 m/ d to 0. 174 mm/ d,the deformation rate is low and gradually tends to 0. 02 mm/ d,indicating the overall stability of the layered roadway. When the width of the layered roadway is less than or equal to 5 m,it has good stability. When the width ranges from 5. 0 m to 5. 4 m it is in an unstable state. Effective support measures can be taken to maintain its stability. In the actual production,the width of the layered roadway should be strictly controlled and the quality of the filling roof should be improved to ensure the safety of the mining operation. 

To address the instability issues associated with coal pillar spalling in thick sandstone roof strata under high mining heights,this study focuses on the control of coal pillar spalling in the 20113 return airway of the Yushuwang Mine as a case study. The characteristics of spalling failure and the primary influencing factors are analyzed. A quantitative characterization method for fracture degree based on the fractal dimension of borehole fractures,using MATLAB image processing technology,is presented. The evolution of the surrounding rock displacement field under four different optimized support schemes is comparatively simulated. A coal pillar spalling control method,centered on " strong roof control,high-resistance rib protection, and inclined I-beam + anchor net coupling control," is proposed and implemented through industrial field tests. The research findings indicate that:① The primary characteristics of coal pillar spalling include diverse failure modes (high-rib wedge spalling + mid-section rib bulging + S-shaped),extensive failure depth,and severe support anchorage failure. ② The superposition effect of thick sandstone strata,low coal strength,abnormal mine pressure manifestation,and significant pillar compression rod effect are the dominant factors inducing coal pillar spalling. ③ The combined support technology of " hydraulic support working resistance enhancement + anchor net cable + anchor cable I-beam" is the optimal support scheme. After adopting this scheme, the convergence of the roadway roof,floor,and ribs were only 143 mm and 181 mm,respectively,representing reductions of 70% and 72% compared to the original support scheme. The loosened zone ranged from 0. 524 m to 0. 613 m,with no significant cracking on the coal pillar surface,and a substantial improvement in the integrity of the anchored coal body. The support effect was favorable,effectively resolving the instability issues of coal pillar spalling in thick sandstone roof strata under high mining heights. 

Due to the large section size and high stress level in the deep chamber,it is more difficult to control the surrounding rock of the chamber. This paper studied the expansion law and influence mechanism of different grouting fluid in the surrounding rock cracks of the deep large-section chamber by measuring deformation failure characteristics and analyzing instability causes of surrounding rock of main drainage pumping-room chamber in Shunhe Coal Mine -702 m horizontal. The reinforcement scheme of " high strength grouting cable+wall grouting" for deep large-section chamber was put forward,and the field industrial test was carried out. The results showed that surrounding rock loose circle in deep large-section chamber was irregular,the loose range was large,the surrounding rock broken degree was high near the gateway:two-side loose range was the largest,the roof second,the floor was small,and rock breaking difference were large in different locations. The causes of surrounding rock instability in large-section chamber were high stress level,low surrounding rock strength,fissure water immersion,poor support structure and no support in floor,and fracture propagation penetration was the main control factor of surrounding rock instability. The influence of grouting pressure on slurry diffusion in surrounding rock cracks was greater than that of water-cement ratio. The larger the water-cement ratio and grouting pressure was,the larger the slurry diffusion radius was,and the tangential expansion range of slurry was larger than that of radial. The optimal water-cement ratio and grouting pressure were 0. 7 and 1. 5 MPa respectively. The high-strength grouting cable achieved uniform anchoring bearing in axial and circumferential. After the reinforcement scheme of " high-strength grouting cable + wall grouting" was carried out,the maximum roof subsidence was 8 mm and the maximum two-side convergence was 24 mm,and the surrounding rock control effect was remarkable. 

In the early stage of a mine in Shandong,room-and-pillar mining was mostly used,leaving a large number of high-quality resources. It will not only cause disasters such as air leakage in the goaf,spontaneous combustion of the seam,instability of the pillar,but also destroy the integrity of the seam,which brings great difficulties to the recovery of pillar resources. Based on the above problems,the coal slurry-based cementing material was proposed to pre-fill the pillar goaf,and the performance test of the coal slurry-based cementing backfilling material was carried out. The flow and mechanical properties of the slurry under the action of additives such as water reducing agent and strengthening agent were tested and analyzed. Considering the creep effect,the effect of increasing the strength of the backfilling and strengthening pillar was quantitatively analyzed. The results show that the water reducing agent C is the main control factor of the slurry expansion degree,the strengthening agent D is the second largest influencing factor of the early strength of the specimen,the cement proportion B is the main influencing factor of the later strength of the specimen,and the mass concentration A is the main common factor of the slurry performance. The lateral constraint provided by the filling body significantly improves the bearing capacity of the pillar,and the creep compressive strength of the pillar increases linearly with the increase of unilateral filling thickness. The results of this study have certain reference significance for the pre-filling room-type empty area of coal slime-based cementing materials and the recovery of underground sluggish mineral resources. 

During the mining process of the fully mechanized top coal caving face along the goaf,due to the large and severe damage area of the upper rock layer,the mining pressure is prominent. In addition,frequent mining activities cause serious damage to the surrounding rock of the narrow coal pillar roadway. Based on this,a comprehensive control technique combining far-field weakening and near-field strengthening,abbreviated as joint prevention and control technology is proposed (referred to as the " combined prevention and control technique" ). This combined prevention and control technique includes two sub-techniques. One is the stability control technique of the goaf based on far-field weakening,which weakens the lateral roof of the goaf through hydraulic cutting,reduces the activation degree of overlying rock,blocks stress transmission,and improves the stress environment of the roadway, thereby reducing stress concentration. The second is the far-field weakening and near-field strengthening reinforcement technique for goaf roadways,which enhances the mechanical properties of the fractured rock mass around the tunnel through anchor support and grouting reinforcement,improves its bearing capacity and deformation resistance, and strengthens the stability of the surrounding rock. The experimental results show that after using the proposed combined prevention and control technique,the maximum approach displacement reduction of the roadway roof and floor is 77. 66% and 61. 96%,respectively,and the maximum displacement reduction of the solid coal support and small coal pillar support is 46. 9% and 72. 75%,respectively. When only using the near-field strengthening technique,the axial force of the anchor rod under near-field strengthening is 118 kN,and the anchor cable is 246 kN. After adopting the combined prevention and control technique,the axial force of the anchor rod is reduced to 93 kN and the anchor cable is reduced to 175 kN,with a decrease of 21. 2% and 28. 9%,respectively. The proposed technique can effectively reduce the support burden and minimize the range of rock damage. The study results are of great significance for ensuring the safety of the fully mechanized mining process in thick coal seams. 

The NPR anchor bolt anchoring structural surface exhibits extraordinary shear resistance under static shear loads,but the mechanical response under dynamic cyclic loads still needs further verification. Using processed original rock samples,a pre-peak cyclic loading shear test was conducted on a homogeneous sandstone structural plane. The influence of factors such as cyclic loading times,loading rates,and different amplitudes on the shear strength of the structural plane was compared and analyzed under two working conditions:non anchoring and NPR anchor anchoring. The results show that:① When the number of cycles is 80,the shear strength of the non anchored structural surface reaches its peak;In contrast,the peak shear strength of the NPR anchor rod anchoring structure surface has significantly improved. ② The cyclic loading rate increases from 1 kN/ s to 1. 5 kN/ s,and the shear strength of the non anchored structural plane decreases faster;On the contrary, when the loading rate increases,the peak shear strength of the NPR anchor bolt anchoring structure surface shows a greater improvement. ③ The cyclic loading amplitude increases from 50% τmax to 80% τmax,and the shear strength of the non-anchored structural plane decreases. However,the shear strength of the anchored structural surface of NPR anchor rod increases,effectively improving the brittle failure characteristics of the no-anchored structural surface. ④ Under different normal stresses,the shear strength of the NPR anchor bolt anchoring structure surface is significantly improved compared to the no-anchoring structure surface. The above research results can provide scientific basis for seismic and explosion-proof design of open-pit mining. 

This study explores the characteristics and development value of associated sedimentary lithium resources in bauxite,analyzes the principles,advantages,disadvantages and economic efficiency of existing extraction technologies,evaluates their development and utilization prospects,and provides a theoretical basis for the efficient and comprehensive utilization of aluminum-lithium resources. By sorting out the occurrence state,distribution law and ore-forming influencing factors of lithium resources in bauxite,the study conducts a comparative analysis of the process principles and application limitations of single lithium extraction technologies such as alkaline leaching,acid leaching,and roasting-acid leaching. Combined with the process logic of mineral processing-metallurgy integrated technology,a systematic evaluation is carried out from the dimensions of resource utilization efficiency,cost-effectiveness and environmental impact. The results showed that lithium is mainly enriched in the low-grade bauxitic rocks and clay rocks at the top and bottom of the bauxite orebody,and its occurrence state and distribution law are regulated by diagenetic-mineralization processes and secondary transformation processes. Single lithium extraction technologies (including alkaline leaching,acid leaching,and roasting-acid leaching) have problems such as substandard quality of aluminum concentrate,low comprehensive utilization rate,and unrecovered associated elements (gallium,scandium and so on),leading to poor economic and environmental benefits. In contrast,the coordination of mineral processing and metallurgy processes enables the simultaneous extraction of aluminum concentrate and enrichment of lithium,reducing the generation of waste residues as well as lowering energy consumption and costs. The associated lithium resources in bauxite constitute a potential large-scale sedimentary lithium resource pool and hold significant development value. In the future,it is necessary to promote the coordinated development of aluminum-lithium resources by deepening research on the lithium occurrence mechanism, optimizing the mineral processing-metallurgy integrated process,and conducting economic and environmental impact assessments. This will help broaden the supply channels of lithium ore resources in China and realize the integration of resource benefits and ecological benefits. 

Particle breakage is a critical process in the fields of mining,chemical engineering,and building materials, where energy dissipation and fragmentation behavior are crucial for engineering design and equipment performance optimization. Traditional experimental methods face limitations in capturing the dynamic breakage process and microscopic mechanisms,in addition to being costly. The numerical simulation approach based on the particle replacement method (PRM) offers an effective means for investigating particle breakage. This method simulates the breakage process by predefined particle replacement modes and breakage criteria. Through literature review and comparative analysis,this paper systematically summarizes the applicability and limitations of three types of breakage criteria based on contact force,stress tensor,and energy,and discusses key issues in replacement modes,such as determination of progeny number,mass conservation,and non-spherical particle modeling. The results indicate that PRM shows promising potential in predicting post-breakage particle distribution and morphology. However,challenges remain,including the lack of unified criteria and the empirical nature of replacement modes. Future efforts should focus on developing universal breakage criteria,advancing multi-physics coupling models,and incorporating machine learning and experimental data to enhance simulation accuracy and engineering applicability. 

Regard the sodium oleate as collector,the regulatory effects of ultrasonic treatment on the interactions among hematite,quartz,and chlorite mixed ores were investigated in both direct and reverse flotation systems. The experimental results indicate that under suitable ultrasonic conditions,the interaction of chlorite in the hematite flotation system can be effectively regulated. When a 200 W ultrasonic power is used to treat the mixed ore containing 10% chlorite for 1 minute,the iron recovery in the concentrate of the direct flotation system increases by 3. 89 percentage points,and that in the reverse flotation system increases by 3. 67 percentage points. Simultaneously,the regulatory mechanism of ultrasonic treatment on the interactions among hematite,quartz,and chlorite was analyzed through SEM-EDS detection,specific surface area analysis,and reagent adsorption amount detection. The research findings reveal that ultrasonic treatment can desorb the fine chlorite particles coated on the hematite surface,which is conducive to the adsorption of flotation reagents on the mineral surface and promotes both the recovery of hematite and the removal of chlorite,thus providing significant theoretical support for the flotation separation of low-grade and complex hematite resources containing chlorite. 

Using fluorapatite and dolomite as research objects,this study investigated the selective effect of the novel inhibitor fulvic acid on flotation separation between the two minerals in a sodium oleate collector system through pure mineral micro-flotation tests combined with Zeta potential,contact angle,and Fourier-transform infrared spectroscopy (FTIR) analyses. The results showed that without inhibitors,both fluorapatite and dolomite exhibited high floatability under sodium oleate action, making their separation difficult. However,under weakly acidic conditions with appropriate fulvic acid addition,fluorapatite was strongly inhibited while maintaining higher floatability for dolomite. Optimal separation was achieved at pulp pH of 5,with fulvic acid of 15 mg / L and sodium oleate of 60 mg / L, yielding a concentrate with P2O5 grade of 33. 86% and recovery of 92. 36% from artificial binary mixed ores,demonstrating excellent selective separation. Further study revealed that fulvic acid competitively chemically adsorbed with sodium oleate on fluorapatite surfaces,selectively reducing surface hydrophobicity and significantly decreasing floatability,thereby enabling effective separation from dolomite. 

In order to investigate the feasibility of enhancing the flotation process of fine-grained molybdenite and improving the recovery rate of molybdenum using micro-nano bubbles,flotation conditions were systematically optimized,and comparative tests were conducted in both tap water and micro-nano bubble water systems. The mechanism by which micro-nano bubbles improve the flotation recovery rate of fine-grained molybdenite was elucidated through contact angle and high-speed camera characterization methods. Results indicated that under the following conditions of regrinding fineness of -20 μm accounting for 73%,rougher pulp concentration of 30%,pulp pH value of 9,sodium silicate dosage of 600 g / t,sodium thioglycolate dosage of 10 g / t,kerosene dosage of 60 g / t,and 2# oil dosage of 40 g / t,a closed-circuit flotation test with " one roughing,two scavenging,and five cleaning" stages was performed. Under the tap water system,a molybdenum concentrate with a grade of 42. 78% and a recovery rate of 82. 03% was obtained. In contrast,under the micro-nano bubble water system,a molybdenum concentrate with a grade of 41. 41% and a recovery rate of 88. 71% was achieved,representing an increase of 6. 68 percentage points in Mo recovery rate. Micro-nano bubbles improve the flotation process by increasing the contact angle of fine-grained molybdenite,enhancing interparticle interactions, and boosting particle-bubble adhesion, thereby improving its flotation recovery rate. This study provides a technical reference and theoretical foundation for improving the recovery of fine-grained molybdenite. 

The upper limit of particle size for conventional flotation is only around 150 μm. Raising the upper limit of flotation particle size can not only reduce grinding energy consumption but also achieve pre-enrichment of ore through pre-selection and tailings rejection under coarse particle conditions. However,coarse particles are mainly poorly-liberated composites, and the adhesion kinetics behavior and regulation mechanism of bubbles on such surfaces are still unclear,resulting in low recovery rates of coarse particle flotation and loss of valuable minerals. To address this issue,this paper studied the liquid film rupture and spreading behavior of three bubble sizes (550,750,and 950 μm) on four hydrophilic surfaces with discrete hydrophobic sites (hydrophobic site diameter 100 μm,and hydrophobic site spacings of 40,100,200,and 400 μm,respectively) through high-speed dynamic observation and MATLAB image processing. It was found that the formation time of the three-phase contact line (TPC) of the bubble was positively correlated with the hydrophobic site spacing,and the average spreading speed and spreading diameter of the TPC were negatively correlated with the hydrophobic site spacing,indicating that an increase in hydrophobic site spacing is not conducive to bubble adhesion and subsequent spreading. As the bubble size increases,the hindrance effect of the hydrophobic site distribution dispersion on the TPC spreading decreases,suggesting that increasing the bubble size on the surface to a certain extent promotes the TPC spreading. The research results are expected to provide certain theoretical support for the intensification of coarse particle flotation processes. 

As a new type of thermal activation technology,microwave has the advantages of uniform heating,green and high efficiency. After microwave activation,the crystallographic properties of clay minerals change. It can be used as a reinforcing material for the development of high-silicon waste rock composite mineral materials. The changes in the mineral crystallographic properties of kaolin,and quartz (the main mineral component in high silica waste rock),before and after microwave activation are investigated. And the possibility of applying activation-modified kaolin as a reinforcing material for the preparation of kaolin-high silica waste rock high-value mineral materials is analyzed from the mineral crystallographic point of view. The changes of mineral crystallographic properties and micro-morphology of kaolin and quartz before and after microwave were characterized and analyzed by thermogravimetric analysis ( TG-DTG),X-ray diffraction ( XRD), scanning electron microscopy (SEM) and other detection methods. The results showed that kaolin is transformed from lamellar kaolin to acicular/ columnar mullite with enhanced structure at 2 kW-18 min after microwave activation;After microwave activation,some quartz changes from α-quartz state to β-quartz state at 2 kW-18 min,the quartz particles become smaller and the contact area increases,which is conducive to the interaction with other minerals. Under the action of microwave activation,kaolin-high silica waste rock composite mineral materials with different properties can be prepared by regulating the crystal phase changes of kaolin and quartz. 

The large lump rate of aggregate mine bench blasting is an important indicator for evaluating the effectiveness of mining blasting. Taking a tuff aggregate mine as an example,firstly,a blasting block size and rock dynamic damage correlation model was established based on field block size distribution and numerical simulation analysis. Secondly,based on this correlation model,numerical simulations of bench blasting in cracked rock mass were carried out with inter-hole delay times of 9 ms,11 ms,13 ms,15 ms,17 ms,and 20 ms respectively,with the main purpose of reducing the large lump rate and taking into account the control of powder ore rate to obtain the best inter-hole delay. Finally,field blasting tests were conducted with the optimized inter-hole delay obtained by the simulation calculation. The results show that there is an exponential function relationship between the blasting block size and the damage value from numerical simulation. In the above delay time,with interhole delay time decreases,the large lump rate gradually decreases and the powder rate gradually increases. When the inter-hole delay time is 15 ms,the blasting effect is the best. The results of mine field application show that when the inter-hole delay time is adjusted to 15 ms,the blasting large lump rate is reduced by 13. 73 percentage points,the powder ore rate increases by 0. 73 percentage points,and the average crushing size is reduced correspondingly. 

In the present stage of open-pit mine blasting,the residual rock powder is used to plug the hole. However,the method of rock powder plugging the hole is relatively primitive,and the plugging effect is poor. Especially,when the charge of the hole is large or the center of gravity is high,blasting punching is easy to occur,and the plugging body cannot intercept the explosion-generated gas well,leading to the leakage of a large amount of blasting energy and poor blasting effect. In order to improve the hole stemming effect,on the basis of previous experimental results,geopolymer was introduced to modify the rock powder stemming material. Based on the content and requirements of open-pit blasting stemming operation,six groups of different material ratios were designed for testing. The setting time and mechanical properties of the products of each scheme were tested,and the best ratio scheme was selected. In addition,the safety of blasting equipment caused by the heat release of geological polymerization reaction and the influence of geological polymerization products on the detonation of detonating tube are analyzed,and the safety of application of modified rock powder material is demonstrated. The numerical simulation of impact crushing of geopolymer modified rock powder stemming material is also carried out. It is considered that the material can form a massive structure similar to gravel under the impact of blasting,and can self-seal with mutual clamping under the shock wave,so as to improve the interception ability of hole stemming body to explosion energy,improve the utilization rate of energy, and thus improve the blasting effect. The parctice results show that the scheme is applied to the sectional charging structure of Pingshuo East Open-pit Mine,and good stemming effect is obtained,and the punching rate and bulk rate are reduced. 

Aiming at the problems such as missing,displacement and information security of boundary piles in territorial space control area,an online monitoring system of boundary piles is designed. By using Beidou positioning,acceleration sensor and Internet of Things technology to develop boundary pile transaction monitoring equipment,a visual boundary pile information management platform was built based on Web technology,and an intelligent mobile inspection application program was designed. Through 4G mobile network communication,functions such as all-weather boundary pile positioning,real-time monitoring of transaction and automatic alarm were realized. The study results show that the system adopts domestic hardware design and low-power MCU,which improves the information security and endurance of the system,effectively replaces the boundary pile protection methods based on artificial field inspection,and realizes the low-cost and high-efficiency boundary pile monitoring. The intelligent boundary pile monitoring system is applied to the measuring sign monitoring of Zhejiang Provincial Department of Natural Resources,and the transfer and displacement of 110 measuring signs in Jiaxing City are monitored all-weather, and the conventional positioning level accuracy reaches 2 m. 

Taking the hybrid electric mining truck as the research object,the energy management strategy based on Dynamic Programming (DP) is established to study its fuel economy,maximize its fuel saving potential and obtain the change law of energy storage and discharge of the hybrid power system. According to the operation characteristics of the hybrid electric mining truck,the driving conditions and the structural scheme of the hybrid power system are constructed,and the backward simulation model is established. On this basis,the optimal control mathematical model with the engine fuel consumption as the optimization goal is established and solved by using DP algorithm. From the obtained simulation results,the hybrid mining truck engine can work more in the fuel economy zone than that of the prototype vehicle,and the fuel consumption is 18. 3% lower than that of the prototype vehicle. At the same time,the variation law of State of Charge (SOC) and current of the power battery in the process of energy storage and discharge is obtained. The results show that the proposed hybrid power scheme is feasible,the energy management strategy based on DP is effective to improve fuel economy,and the mining truck has greater energy recovery potential. This study provides a theoretical basis and reference for the subsequent development of energy management strategies for hybrid electric mining trucks.

Coal ash content is one of the key indicators for evaluating coal quality. The content and properties of ash significantly impact combustion equipment,the environment,and subsequent processing and utilization. To address the issues of lagging and labor-intensive methods in current coal ash detection,an intelligent prediction algorithm for coal ash content based on X-ray Fluorescence (XRF) spectroscopy combined with Preprocessing (PRE) and Partial Least Squares (PLS) regression is proposed. The process involves inputting spectral data of coal samples obtained via XRF technology into the PLS main model for an initial ash content prediction. Relevant correction parameters are then fed into a parameter compensation optimization model. The final predicted ash content value is derived by summing these two results. Experimental results indicate that,compared to partial least squares regression and neural network (NN) regression models,the PRE-PLS model exhibits the smallest fluctuation range in relative error. Compared with partial least squares regression and neural network regression models, the determination coefficient of the PRE-PLS model is 0. 995 1, the root mean square error is 0. 941 1, and the mean absolute error is 0. 733 2%. This indicates that this model has high accuracy and is capable of performing on-site detection tasks, providing reliable guidance for production. 

The path planning of the mining area inspection robot faces challenges such as complex environments,dynamic obstacles and uncertain factors. Therefore,a path planning idea integrating the improved Rapidly-exploring Random Tree algorithm (RRT) and the Artificial Potential Field (APF) method is proposed. This method is based on the RRT algorithm and introduces the Random Walk (SW) algorithm for optimization of the search strategy. On this basis,to further improve the adaptability and obstacle avoidance ability in dynamic obstacle environments,the calculation method of the gravitational and repulsive force parameters in the APF algorithm is optimized and improved. Finally,a path planning model for the mining area inspection robot integrating SW-RRT and IAPF (SW-RRT-IAPF model) is proposed. The experimental results show that the path planning success rate of the SW-RRT-IAPF model is the highest at 97. 13%,the path smoothness is the highest at 93. 61%,and the average path planning time is the shortest at 0. 66 seconds. Compared with traditional methods,the path planning time in complex mining environments is reduced by approximately 35%,and the path smoothness is improved by 22%. The proposed model can optimize the path planning efficiency in both daytime and nighttime environments,effectively avoid dynamic obstacles,and provide a new solution for the path planning of mining area inspection robots. 

The high-intensity exploitation of mineral resources has led to increasingly severe dust problems in mines,seriously threatening the safety of underground production and the occupational health of workers. Spray dust suppression technology can effectively control dust,and the quality of spray characteristics is strongly related to the final dust suppression effect. Improving the atomization effect can effectively improve the working environment. Compared with single-fluid pressure nozzles,dual-fluid atomizing nozzles have obvious advantages,but the interaction between the internal and external flow fields of the nozzle and the liquid medium is complex. The intermediate parameters in the field application have not been deeply studied,resulting in poor targeted control of spray characteristics and difficulties in achieving efficient dust suppression. Based on this,the air atomizing nozzle in the dual-fluid atomizing nozzle was taken as the research object. The influence forms and laws of two key parameters,water supply pressure and gas supply pressure,on five spray characteristic parameters,namely range,water flow rate, gas flow rate,D50 and D90 ,were studied. The grey relational analysis method was used to analyze the importance of different parameters on spray characteristics,and the sensitive indicators of different spray characteristic parameters were determined. The spray process was optimized and controlled. The study results show that water supply pressure is positively correlated with range,water flow rate and droplet size,and gas supply pressure is positively correlated with gas flow rate;range and water flow rate,gas flow rate,and droplet size are respectively sensitive to changes in water supply pressure,gas supply pressure,and liquid-gas pressure ratio. The research results can achieve targeted control of spray characteristics and provide a theoretical basis for accelerating the construction of a wet dust control system in mines. 

In order to solve the problem that the existing foam dust removal technology in fully mechanized mining face is greatly influenced by the head-on wind and underground wind and water parameters,a high-energy fine bubble dust suppression system composed of a new fine bubble generator,a diverter and an adjustable umbrella-shaped anti-blocking nozzle is developed. The new fine bubble generator consists of a water jet premixing and diluting section,a gas-jet double-pressure flow assisting section and a mixer high-efficiency foaming section. By building a multi-characteristic experimental platform of fine bubbles based on phase Doppler particle analysis technology,the macro-and micro-wind resistance parameters of fine bubbles with different axial opening and closing sizes of nozzles and different bubble generating liquid concentrations were tested,and the relationship between foaming multiple of fine bubbles and wind resistance was clarified,revealing the action mechanism of disturbed airflow on fine bubbles. The results show that the atomization angle of the nozzle decreases sharply with the increase of the axial opening and closing size of the nozzle,and the optimal axial opening and closing size of the nozzle is 2 mm by considering the farthest range and the maximum coverage radius of the fine bubbles. The attenuation rate of airflow disturbance on bubble velocity and the change rate of bubble particle size both decrease at first and then increase with the increase of foaming multiple. Combining foaming multiple and wind resistance,the optimal concentration of bubble generating liquid is 0. 9%. Based on the study results and combined with the field situation,a dust suppression system was established for the 15115 fully mechanized mining face in a mine. The application results showed that the fine bubbles did not turn back with the reverse airflow,and the maximum dust suppression rate of fine bubbles on the fully mechanized mining face was 94. 3% and 91. 8%,which realized the accurate coverage of the tunneling dust source. 

Rockburst is a frontier issue in the field of rock mechanics and engineering worldwide and a safety challenge that restricts the implementation of deep mining strategies in China. The key to rockburst prevention and control lies in the study of its mechanism,and the stiffness theory is an important aspect of this study. By reviewing a large number of study papers on rockburst stiffness theory,this paper systematically summarizes the development history of the stiffness theory,the experimental methods and typical experimental results,the rockburst body-surrounding rock system model,and the rockburst criteria. The study results show that:① The stiffness theory originated from the energy theory and has been enriched and developed,but it is still difficult to fully explain the mechanism of rockburst;② The evolution of the stiffness testing machine has driven the stiffness theory experiments to shift from controlling the stiffness of the rock sample to controlling the stiffness of the testing machine. The necessary condition for rockburst occurrence is that the stiffness of the testing machine is lower than that of the rock sample,and the intensity of rockburst increases with the increase of the stiffness difference between the two;③ The rockburst stiffness system model regards the rockburst body and the surrounding rock as an elastic-plastic composite body,and the system model considering the energy storage capacity of the rock sample is more in line with the actual situation;④ The existing stiffness calculation methods mainly focus on indoor rock samples and testing machines,and the rockburst criteria based on the stiffness theory are still limited to determining whether rockburst occurs. By analyzing the existing problems in the stiffness theory study,this paper looks forward to further study directions such as dynamic variable stiffness tests,stiffness theory criteria for different grades of rockburst,and in-situ rockburst stiffness theory study based on engineering cases. The analysis results can provide reference for the theoretical study and engineering application of rockburst stiffness. 

With the continuous expansion of the scale of engineering construction and resource exploitation,the seismic safety and seismic reinforcement measures of various slopes have received increasing attention. Taking the viscous soil slopeanti-slide pile system as the research object,multiple sets of real seismic waves were selected,and a series of three-dimensional numerical analyses were carried out using the finite difference software FLAC 3D . The influence of factors such as the position, length and spacing of anti-slide piles on the deformation characteristics of the reinforced slope under strong earthquakes was systematically investigated,and a comparative analysis was conducted with the deformation law of the un-reinforced slope under seismic action. The research shows that anti-slide piles can significantly improve the seismic stability of slopes. The dynamic stability coefficient of the anti-slide pile reinforced slope obtained by the dynamic strength reduction method is 1. 43,which is about 6% higher than that of the un-reinforced slope. When the horizontal distance from the anti-slide pile to the slope shoulder is 0. 7 times the horizontal projection length of the slope surface,the acceleration amplification coefficient and the average permanent displacement of the reinforced slope surface are reduced most significantly compared to the un-reinforced slope,by approximately 8% and 10% respectively. This working condition has the best reinforcement effect. The pile length of 10 times the pile diameter is more appropriate. When the pile length is less than 6 times the pile diameter,the reinforcement effect is not obvious. When the pile length exceeds 10 times the pile diameter,the improvement in the reinforcement effect of the anti-slide pile is relatively small. As the pile spacing increases,the soil arching effect between piles weakens,and the reinforcement effect of the anti-slide piles gradually decreases. 

In order to solve the problem of lack of irrigation water source for the ecological restoration of dump,this paper intends to build a reservoir on the top platform of the dump and analyze the influence of the reservoir on the stability of the dump. Taking a mine dump as the study object,based on the strength reduction principle,the stability of three kinds of support schemes (wall between piles,wall between piles-skeleton and wall between piles-skeleton-hardened platform) is trialed to be contrasted and analyzed by the finite element software MIDAS / GTS. The best support scheme was determined by combining the ecological restoration factors. On this basis,the influence of reservoir construction on the stability of the dump was discussed. The study results show that compared with the wall between piles support scheme,the wall between piles-skeleton support scheme and wall between piles-skeleton-hardened platform support scheme have higher safety. However,the wall between pilesskeleton-hardened platform support scheme can not significantly enhance the stability of the dump but cause part of land loss in the dump,which means the before and after reclamation available land area decreases. Therefore,the wall between piles-skeleton support scheme is considered as the best one. When the reservoir is constructed at the front of the top platform,the stability of the dump decreases with increasing reservoir capacity. When the reservoir is built in the middle or rear,the reservoir capacity increases while the stability of the dump remains basically unchanged. When the reservoir capacity is certain,the layout position moves from the front of the top platform to the middle,and the stability of the dump increases. When the layout position moves from the middle of the top platform to the rear,the stability of the dump remains basically unchanged. The study results can provide theoretical basis for the maintenance of dump slope platform and ecological restoration of dump. 

As a artificial high-potential energy hazard source,the tailings pond poses a serious threat to the downstream lives,property,and ecological environment. Based on the downstream topographic conditions of a tailings pond,a fine three-dimensional finite element model for dam breach was established,and a mathematical model describing the flow law of dam breach slurry was proposed utilizing the finite volume method,and then a quantitative evaluation of the dam breach impact on the downstream villages was conducted comprehensively. The study result reveals that almost all the villages at the downstream were submerged. The areas of the submergence depths over 20 m and 40 m are about 56. 5% and 28. 3%,respectively. The flow pattern of the dam breach slurry is significantly influenced by the downstream slope,and the whole process can be divided into three stages:the discharge velocity of slurry is rapid in the initial stage of the dam breach,the average velocity at the downstream reaches 17. 3 m/ s,and then it significantly decreases to 0. 54 m/ s in the second stage,and the slurry begins to expand laterally to the left and right banks,finally,in the last stage of the dam breach,the slurry reaches a stable state and does not flow. The findings of this study provide a fundamental basis for the impact assessment of the tailings pond breach,and they also offer insights for other similar engineering studies. 

The Jiguanzui Cu-Au Deposit is located in the southeastern part of Hubei Province,an important Cu-Fe-AuMo mineral accumulation zone in the middle and lower reaches of the Yangtze River in China. The orebody is mainly in the form of veins and thin plates,and the deposit is controlled by the fault contact zone structure and the goose shaped fractures in the marble. It belongs to the high to medium temperature gas-liquid type copper gold deposit after the magmatic period. Taking 927 pieces of primary halo data from 8 boreholes in No. 28 exploration line profile of No. Ⅶ Cu-Au deposit in Jiguanzui as the study object,factor analysis,correlation analysis,and cluster analysis were used to study the degree of element affinity in the deposit. The Grigoryan zoning index method was adopted to determine the axial zoning sequence of the primary halo,and combined with the abnormal characteristics of the primary halo and the geochemical parameters of the primary halo,mineralization prediction was made for the hidden ore body in the deep edge of No. Ⅶ deposit. Research has shown that:① There is a strong correlation between Au,Cu,Co,W,and Mo,and Au,Cu,Ag,Zn,and Pb are the most direct indicator elements for mineralization. ② The axial zoning sequence of the primary halo of the ore body is As-Sb-W-Co-Au-Ag-Ni-Pb-Zn. The leading edge halos As and Sb coexist with the trailing edge halos W and Mo,and the trailing edge element Ni appears in the upper part of the near ore indicator elements Pb and Zn. The indicator orebody is formed by the superposition of multiple phases,and there is a possibility for the orebody to extend towards the two side boundaries in the axial direction. ③ The ratio of elements in the leading edge halo and tail halo reflected by w(Sb) / w(W) and w(As+Sb) / w(W+Ni) are relatively large at the boundary and shows an increasing trend,indicating the possibility of the orebody extending along the axial direction to both sides. Based on comprehensive analysis,it is believed that there are still mineralization conditions and trends on both sides of the section of No. Ⅶ orebody on No. 28 line of Jiguanzui,and further engineering verification is necessary. 

The Quanji Massif is located in the northeastern part of the Qinghai-Tibet Plateau and possesses significant potential for sedimentary metamorphic iron ore mineralization. However,due to its harsh natural conditions,geological research and metallogenic prediction in this region have not been thoroughly conducted,thereby constraining regional mineral exploration breakthroughs. Through systematically analyzing the regional geological framework of the study area,a mineral prospecting prediction model for sedimentary metamorphic iron deposits in the Quanji Massif was established. Based on a mineral exploration prediction model, the study utilized high-resolution hyperspectral data from GaoFen-5 and applied a combination of MNF (Minimal Noise Fraction),PPI ( Pixel Purity Index),and SAM ( Spectral Angle Mapper) methods to extract five indicator minerals from the study area:hematite,goethite,hornblende,muscovite,and chlorite. The study also integrates magnetic anomaly data and geological mapping data to establish a mineralization prediction dataset. Finally, the Fuzzy Analytic Hierarchy Process was applied to assign weights to multi-source metallogenic prediction data. The metallogenic favorability degree was calculated through the Index Overlay method,based on which five prospecting target areas were delineated and subjected to field verification. The results of the study indicate that the method of extracting indicator minerals based on hyperspectral data can provide crucial data support for the mineralization prediction of sedimentary metamorphic iron deposits in the study area. The delineated prospecting target areas provide crucial guidance for the exploration of sedimentary metamorphic iron deposits in this region. 

Deep goad in mines have become a significant hazard to the safety of personnel and production equipment in mines. In response to the problems of high cost,poor timeliness,and numerous measurement blind spots in existing deep goaf detection methods,a penetrating three-dimensional laser radar scanning system has been designed for goaf detection. This system uses an inexpensive mechanical rotating laser radar to reduce costs;through an independently designed graph optimizationbased Cartographer-SLAM (Simultaneous Localization and Mapping) algorithm,it can quickly process laser radar data,achieving real-time positioning and mapping underground,thereby improving timeliness. Coupled with a penetrating three-dimensional laser radar scanning system bracket,it can measure in dangerous roadways,goafs,and other areas that are difficult for personnel to access,effectively reducing measurement blind spots. To address the issues of unsmooth and hole-ridden void models constructed by existing modeling algorithms,a Poisson surface reconstruction algorithm optimized by the Moving Least Squares (MLS) method is proposed to model the void goaf cloud data. By performing high-order polynomial interpolation around the data points using MLS,and through octree segmentation,vector field calculation,Poisson equation solving,and isosurface extraction,a three-dimensional model of goaf is constructed. The experiment was conducted in a gold mine in Liaoning Province, where data from multiple goaf,roadways,and underground chambers were collected to achieve precise underground space modeling. The experimental results show that the designed system and algorithm can efficiently and accurately achieve three-dimensional modeling of deep and complex goafs,to a certain extent solving the problems of difficult access to goafs,measurement blind spots,and insufficient modeling accuracy in deep and complex goaf detection,providing important technical support for mine goaf management and safe production. 

High-resolution remote sensing images are of great significance for geological exploration,resource assessment, and mine safety management. Using Generative Adversarial Networks (GAN) for single-image super-resolution reconstruction of mine remote sensing images can improve image quality and enrich image details. However,this method still has problems such as unstable training process,differences between generated image details and real ground objects,and the tendency to produce artifacts in practical applications. Therefore,an improved attention mechanism-based GAN algorithm for enhancing mine remote sensing images is proposed. The generator integrates the Pyramid Split Attention (PSA) module and Residual Dense Block (RDB),significantly enhancing the feature extraction capability. The PSA module can effectively capture multi-scale image features and improve the model′s sensitivity to details;the RDB promotes the full flow of information in the network through dense connections, further enhancing the feature representation ability. For the discriminator, Spectral Normalization ( SN) technology is adopted instead of the traditional BN (Bath Bath Normalization) layer to enhance the learning ability of mine remote sensing image details and reduce the discriminator′s neglect of generated image details. Additionally,based on the theory of Wasserstein Generative Adversarial Network with Gradient Penalty (WGAN-GP),the adversarial loss function is optimized by introducing a gradient penalty term,stabilizing the training process and accelerating the model′s convergence speed. Experimental results show that the proposed algorithm outperforms the original GAN algorithm in terms of detail texture richness and artifact reduction. The Peak Signal-to-Noise Ratio (PSNR) of the processed remote sensing images is increased by 0. 536 to 1. 897 dB,and the Structural Similarity (SSIM) is increased by 0. 019 to 0. 089. 

In order to improve the problem of low yield of calcium sulfate whiskers prepared by atmospheric pressure acidification. In this study,ultrasound and chloride additives (sodium chloride and calcium chloride) were used to improve the yield of whisker products. The results showed that when 8 g of phosphogypsum reacted with 400 g of acid leaching solution under the conditions of ultrasonic frequency of 40 kHz and sodium chloride concentration of 1. 5 mol / L,while calcium chloride with mass ratio (calcium chloride / phosphogypsum) of 1. 5 was added after the reaction,the whisker yield reached 77. 63%. The mechanism study shows that the sodium chloride increases the whisker yield by promoting the dissolution of phosphogypsum through charge effects and salt effects. Meanwhile,the calcium chloride improved the yield of whiskers by increasing the degree of crystallizeout through the coion effect. In addition,the whisker yield improving process produced calcium sulfate dihydrate whiskers with purity 99. 78%,whiteness 96. 43% and length-diameter 78,which met the requirements of the industry standard (DB43 / T 1155—2016). 

This study prepared tin disulfide (SnS2 ) photocatalysts with different dominant crystal facets exposed using a hydrothermal method,and systematically investigated their structure,morphology,photocatalytic performance,and mechanisms. The SnS2 samples were characterized using X-ray diffraction (XRD),scanning electron microscopy (SEM),and ultraviolet-visible diffuse reflectance spectroscopy (UV-DRS). The results indicated that SnS2 with exposed (001),(101),and (110) crystal facets were successfully synthesized,exhibiting block-like,flower-like,and hexagonal flake morphologies respectively. Under simulated sunlight irradiation,the crystal facets of SnS2 demonstrated significant catalytic oxidation anisotropy for sodium butyl xanthate (SBX),following the order (101),(001),(110). The superior photocatalytic activity of the (110) facet was attributed to its enhanced photogenerated carrier migration,reduced electron-hole recombination rate,and improved light absorption capacity. Radical quenching experiments revealed that 1O2 served as the primary active species in the photocatalytic degradation process. This research provided a theoretical basis for optimizing the performance of SnS2 photocatalysts through crystal facet engineering and offered references for their application in wastewater treatment. 

Coal gasification slag (CGS) is a by-product of the coal gasification process,and the mineral phase containing amorphous silica-aluminate gives it the potential to be used as a cementitious material. In this study,the activation pretreatment of CGS was carried out by mechanical milling to explore the applicability of CGS in cementitious materials,and the hydration reaction process was analyzed by a series of characterization means,such as XRD,SEM,TG-DTG,and FTIR,to elucidate the mechanism of the milling time on the particle properties of CGS and the activity of volcanic ash. The results showed that the particle size of CGS showed a decreasing and then increasing trend with the increase of grinding time,and the characteristic particle size of CGS reached the minimum value when grinding for 80 min,and the D10 ,D50 and D90 were 1. 0 μm,4. 7 μm, and 23. 6 μm,respectively. The mechanically milled CGS for 80 min showed optimal cementing performance,and the 28 d activity index of cementitious sand was 91. 5%. The 28 d compressive strength was up to 46. 5 MPa,which was 120. 4% higher than the compressive strength of the unactivated cementitious sand,and met the requirements for the use of volcanic ash mixes. In addition,the mechanical grinding process destroys the crystal structure of CGS,which is conducive to the release of active substances,and generates a large number of hydration products dominated by calcite,Ca(OH)2 and C-(A) -S-H gel,which has a significant enhancement effect on the activity of volcanic ash. From the microscopic morphology,it can be seen that with the increase of activation time,the microstructure of the hydration products is gradually uniform and dense. This study provides a green and low-carbon solution for the resourceful,large-scale and high-value utilization of coal gasification slag,which is of great significance for achieving carbon peak and carbon neutrality.