To address the insufficient adaptability of traditional single-objective scheduling models for underground metal mines,a multi-objective scheduling optimization model for stoping equipment was constructed.The model takes the minimiza tion of the makespan and total inter-operation interval time as the optimization objectives and incorporates the actual working condition characteristics of equipment operating states and resource requirements in ore mining,haulage,and hoisting.To rea sonably transform the multi-objective scheduling problem into a solvable single-objective decision model,a multi-objective com prehensive weighting method based on the Analytic Hierarchy Process-Entropy Weight Method (AHP-EWM) was designed.By combining static weighting with dynamic weight adjustment,this method achieves precise weight configuration of multi-objective parameters.Taking the weighted single-objective comprehensive optimization model as the object to be solved,and considering the inherent shortcomings of traditional genetic algorithms,such as slow convergence and susceptibility to local optima,adaptive operators and a simulated annealing mechanism were introduced,and an Improved Genetic Simulated Annealing Algorithm (IGASA) was proposed.Case study results show that,compared with conventional scheduling methods,the proposed method reduces the makespan by 36.54% and the total inter-operation interval time by 38.13%,indicating significantly improved scheduling performance.Furthermore,to intuitively apply the obtained scheduling scheme to production management,a process architecture for a production scheduling digital twin system was proposed,which supports dynamic simulation and real-time mo nitoring of scheduling plans,thereby forming a complete technical chain of "weight configuration-model solving-visualization presentation" and providing a theoretical basis and technical support for constructing intelligent scheduling systems for under ground mines.

The pivotal systemic engineering issue in ore production is controlling energy consumption across the full process,from blasting through mechanical crushing and grinding.To address the paramount need for collaborative efficiency im provement in large open-pit metal mines,and based on a review and synthesis of research progress in China and abroad,together with the authors′decade of research on multi-process coupling in large mines,this paper proposes energy-flow transfer in ore fragmentation within open-pit metal mines as a central concept.Its aim is to address fragmentation in mining processes,achieve full-process energy optimization,and guarantee a stable supply of ore with consistent quality.Accordingly,this paper reviews re search progress in several areas,including energy-consumption modeling for rock fragmentation based on intelligent perception during drilling,three-dimensional information extraction of blasting fragmentation,the use of spatial distribution features of blas ting fragmentation to guide loading and ore blending,coupled control of ore crushing efficiency based on differences in blasta bility,and the developmental characteristics of blasting vibration energy.The results show that:① A rock fragmentation energy model constructed from field drilling parameters,combined with energy-time density indices along with efficiency evaluation functions,can effectively characterize rock-mass properties and provide a foundation for the rational regulation of energy con sumption among blasting,crushing,and grinding processes.② Through integrating three-dimensional laser scanning,3D Gauss ian splatting,and machine-learning algorithms,blasting fragmentation is able to be characterized from two-dimensional images to three-dimensional shape features and volume calculations,providing key data support for crushing energy-consumption calcu lation and crusher parameter refinement.③ Based on an adaptive layered model of the muckpile,improved path-planning algo rithms,and a multi-goal intelligent ore-blending system,a refined operational chain has been established that links the spatial distribution of fragmentation,loading-path optimization,and coordinated ore blending across multiple mining areas,thereby ef fectively supporting improvements in loading efficiency and stability of ore quality.④ The matching of explosives and rock based on blastability zoning,together with coupled control of crushing efficiency that accounts for fragmentation characteristics, can improve the utilization efficiency of explosive energy and reduce full-process energy consumption.⑤ Blasting vibration en ergy indicators are sensitive to the structural response of the rock mass,enabling blasting vibration,traditionally regarded as an adverse effect,to be transformed into an effective auxiliary means for inferring rock-mass information in the area to be blasted. Building on this,the paper further discusses key research directions for the field during the 15th Five-Year Plan period and be yond.Future research ought to focus on the construction of integrated terrain-geology-grade models and refined blastability zon ing,intelligent matching of explosives and rock based on blastability zoning and on-site mixed charging technologies,full process coupled control of ore crushing efficiency based on differences in blastability,and characterization of rock-mass struc ture and damage features using blasting vibration energy indicators.These efforts are expected to add to a systematic solution for full-process energy optimization and stable ore-quality supply,thereby supplying theoretical foundations and technical support for green,efficient,and intelligent mining in large open-pit mines

Seasonal fluctuations in temperature and water quality are critical inducing factors responsible for periodic var iations in flotation performance indicators of mines under complex environmental conditions.Nevertheless,most existing studies treat these variables as independent individual factors,lacking systematic insights into their synergistic effects mediated by slur ry rheological properties and gangue minerals.From a rheological perspective,this paper systematically elaborates on the mech anisms through which seasonal temperature shifts,water quality variations,and their synergistic interactions with gangue miner als alter slurry rheological behaviors.The key analyses focus on three aspects:① The physicochemical fundamentals whereby temperature regulates particle aggregation/dispersion and reagent diffusion by modifying the viscosity of the continuous phase and Brownian motion of solid particles;② The rheological effects of multivalent cations such as Ca2+ and Mg2+ in strengthening clay flocculation networks via electric double layer compression and cation bridging mechanisms;③ The underlying mecha nisms linking variations in slurry yield stress and viscosity to inter-particle interactions,selective reagent adsorption,and foam stability.On this basis,the inherent correlations among seasonal variations,slurry rheological behaviors,and flotation perform ance indicators are clarified.The limitations of current research and prospective research directions are also highlighted,aiming to provide theoretical support for stable and high-efficiency production of mines operating under complex environmental condi tions.

With the sustained growth of global photovoltaic (PV) installed capacity,early-service modules are gradually entering their end-of-life phase,making the resource recovery of retired crystalline silicon PV modules an urgent engineering challenge in the circular economy.PV glass and silicon materials constitute two core high-value components;However,current mainstream recycling processes predominantly resort to downcycling both,resulting in a massive waste of high-purity silicon and premium quartz resources.On the basis of delineating high-value utilization pathways for recovered silicon and PV glass,this paper systematically investigates the impurity removal mechanisms of various wet chemical systems,with a focus on the challen ges of interfacial metal impurity adhesion and the transformation of their occurrence states induced by module dismantling and pretreatment.The performance differences among four types of systems—traditional inorganic strong acids,alkaline etching,or ganic acid complexation,and novel deep eutectic solvents (DES)—are compared in terms of metal removal efficiency,etching selectivity,and their capacity to preserve the intrinsic structures of the silicon lattice and the silica network.The results show that although traditional strong acid systems deliver high impurity removal efficiency,they non-selectively damage both the sili con substrate and the glass matrix while posing significant environmental risks. In contrast,DES,serving as a green and mild medium,exhibit high selectivity,low corrosivity,and excellent recyclability,enabling synergistic and non-destructive purifica tion of silicon and glass,and thus represent the most promising technological direction for future development.This paper chartsa pathway for transforming the PV recycling paradigm from simple precious metal extraction toward the synergistic high-purity regeneration of silicon and glass,providing a theoretical basis and engineering reference for the low-carbon,high-quality recy cling of retired photovoltaic materials.

To promote the promotion and in-depth development of synergetic mining technology,the researches about technical characteristics and paradigm model of synergetic mining technology are carried out.Firstly,the relationship between the synergetic mining mode and the traditional mining mode is discussed and the concept of "core mining process chain" is proposed,and its different positions in two modes were explained.Secondly,a discrimination method for synergetic mining tech nology is provided.Thirdly,the technical characteristics of synergetic mining are summarized and analyzed,which mainly in clude multi-objective attribute characteristic,order parameter driven characteristic,subsystem synergy characteristic,process networking characteristic,system self-organization characteristic,etc.Finally,paradigm model of synergetic mining and its tech nology are proposed.The research results can provide certain assistance for industry practitioners to understand,identify,and develop synergetic mining technologies.

Once the teeth of loading equipment in open-pit mines fall off or break,they are highly likely to enter subse quent crushing processes along with the material,potentially causing catastrophic damage to the crushing system and incurring immeasurable direct and indirect economic losses to the enterprise.Although a few literature reports and patents on online mo nitoring and alarming for missing teeth exist,the real-time performance of such systems remains inadequate for on-site require ments due to limitations of traditional machine learning algorithms and the computing power of mobile devices.As a result,few technologically mature products have actually been applied in engineering practice.To address this major safety issue that has long plagued open-pit mines worldwide,this study employs the multi-object detection YOLOv5 algorithm based on machine vi sion,combined with a hierarchical feature description strategy from low to high levels,to develop an integrated monitoring sys tem that performs real-time online monitoring and intelligent alarming of the working status of dipper teeth,capable of issuing timely warnings against tooth loss accidents.The system has been put into practical application on various types of loading e quipment in China,and its operational performance has verified its reliability,real-time capability,and accuracy.It can effec tively reduce safety risks in mining production,prevent significant economic losses caused by missing teeth,and provide solid technical support for the construction and improvement of digital,intelligent,unmanned,and scientific management platforms in open-pit mines.

　Mineral resources serve as the cornerstone of national economic security and industrial development,while deep mining constitutes a strategic approach to address the high external dependence on critical minerals and insufficient sup ply chain resilience.In the face of extreme geological conditions and complex construction environments in deep metal mining operations,the structural defects of the traditional drill-blast method in terms of efficiency,safety and cost have become increas ingly prominent.As a preferred solution for the intelligent transformation of mine roadways,the full-face hard rock Tunnel Bor ing Machine (TBM) offers comprehensive advantages including high safety,efficiency and tunneling quality.This paper sys tematically analyzes the engineering characteristics and mining demands of metal mines,and constructs a dedicated TBM tech nological innovation system adapted to metal mines around five dimensions:advanced geological detection and real-time percep tion,equipment structural integration and flexibility,enhanced stratum adaptability,efficient roadway construction technology, and intelligent remote control.The system has successfully broken through key technical bottlenecks such as ultra-small turning radius,steep slope and long-distance hard rock tunneling,and these breakthroughs have been verified in a number of typical projects.Finally,this paper prospects the future development directions of mining TBM,such as transparent geology adaptation and equipment diversification.The research results not only expand the application theory and technical system of mining TBM,providing a complete set of solutions for the efficient,safe,green and intelligent mining of deep metal mines,but also pos sess significant theoretical value and engineering significance for improving the self-sufficiency of critical mineral resources and promoting the intelligent transformation of mines.

The surrounding rock of the Liutangfang Iron Mine in Anhui Province exhibits a gently inclined layered struc ture,making it inherently prone to rock delamination and collapse during extraction;as mining depth increases,the roadway roof support system and its parameters urgently require optimization and upgrading.To address this,joint and fracture parameters of the ore rock were first statistically analyzed to classify the quality of the deep surrounding rock,and then a subitem quantitative weighted scoring method was adopted to rate the roof support grade based on three primary factors:surrounding rock quality classification,crosssectional dimensions,and service life and function.Subsequently,numerical simulations of roadway stability were conducted under various support methods and parameters,which revealed the influence mechanisms of different support techniques on the extent of the loosening zone,stress concentration zones,and plastic zones,while also quantitatively assessing the effects of concrete,rock bolts,and boltmesh combined support on maximum roadway settlement and roof control ratio.The results show that,within the constraints of support cost,the order of influence on support effectiveness is concrete thickness> bolt spacing>mesh reinforcement>bolt length;When the support effectiveness falls below 30%,the system is undersupported and increased expenditure can significantly improve performance,whereas when it exceeds 45%,the system becomes oversup ported and further cost increases yield only marginal gains.Finally,based on a comparative optimization of support effectiveness and cost,a set of graded support schemes and parameter optimization proposals is put forward,and the findings are expected to provide a useful reference for roof classification and support design in similar underground mining projects.

Stability control of newly excavated roadways in layered backfill is critical to ensuring safe underground mining operations.Taking a phosphate mine in Guizhou Province,as the engineering background,this study introduced the Coal Mine Roof Rating (CMRR) method and employed a comprehensive research approach combining field investigation,laboratory tes ting,and theoretical analysis to evaluate the roof quality grades of newly excavated roadways within layered backfill,and to as sess the applicability of the CMRR method to backfill mining in phosphate mines.Based on the rating results and onsite condi tions,the roadway support scheme was optimized.Numerical simulations were conducted to compare and analyze,before and af ter support optimization,the displacement distribution of the roadway roof,support structure displacements,plastic zone distri bution,and dissipated energy density characteristics.Field industrial trials were carried out,and roof separation monitoring data over 69 days were obtained to validate the numerical simulation results.The findings indicate that the CMRR ratings for the two monitoring points in the newly excavated roadway within the backfill correspond to a moderate roof and a weak roof,respective ly.The optimized support scheme significantly improved roadway stability:the maximum roof settlement and horizontal displace ment were both reduced by 80%,bolt displacement decreased by 79.6%,the extent of the plastic zone shrank by 52.2%,and the dissipated energy density dropped by 91.5%.These results confirm the applicability of the CMRR method for quality evalu ation of layered backfill masses and provide both theoretical and practical references for innovating stability control technologies for newly excavated roadways in such backfill environments.

Understanding the evolution of meso-structure and mechanical properties of fractured granite under wetting-dr ying and freezing-thawing cycles is of considerable significance for slope stability assessment,safe operation of mining engineer ing,and analysis of long-term service performance.To quantitatively investigate the influence of these cyclic actions on the me so-structure of fractured granite,CT scanning and Low-field Nuclear Magnetic Resonance (LF-NMR) techniques were em ployed to systematically characterise the fracture evolution,pore structure parameters,and pore size distribution of granite spec imens subjected to various cycle numbers.In addition,cyclic loading-unloading tests were conducted to examine the macroscop ic mechanical response.The results indicate that with increasing numbers of wetting-drying and freezing-thawing cycles,both the number and size of micro-cracks within the granite continuously increase,and the fractures gradually evolve from a discrete distribution into an interconnected network,accompanied by a marked enhancement in pore connectivity.The pore structure progressively shifts from being dominated by micropores towards mesopores and macropores;specifically,the proportion of mi cropores decreases by 12.36%,while the proportions of mesopores and macropores increase by 5.54% and 6.82%,respectively.The macroscopic mechanical test results show that the stress-strain response of granite under cyclic action exhibits distinct staged characteristics.After 30 cycles,the peak strength decreases by 8.6% relative to the initial peak strength,displaying a consistently deteriorating trend that is closely correlated with the evolution of pore structure.The wetting-drying and freezing thawing cycles,through repeated water absorption,freezing and thawing,induce pore expansion and fracture coalescence,which constitute the primary intrinsic mechanism responsible for the degradation of mechanical performance in fractured granite.

Evaluation of rock mass integrity plays a vital role in geotechnical investigation,design and construction.Tak ing the open-pit high slope of the Hongge South vanadium-titanium magnetite mine in Yanbian County,Sichuan Province,as the engineering background,borehole television tests were conducted on 10 investigation boreholes with a total footage of 1 630.21 m.By comparing the borehole television panoramic images with the fracture characteristics of the corresponding cores,a rock mass integrity index designated RQ was proposed based on borehole television technology.The Particle Swarm Op timization (PSO) algorithm was subsequently adopted to determine the optimal blockiness weight coefficients in the governing formula.The results indicate that:① The optimal blockiness weight coefficients in the RQ calculation are (0.71,0.68,0.62, 0.87),and the RQ values show a strong correlation with the P-wave velocity of the rock mass;② Among the various litholog ical units of the slope rock mass in the Hongge South open-pit mining area,the largest mean error between RQ and core RQD occurs in olivine pyroxenite (21.2%),whereas the smallest is observed in syenite (8.6%);③ Compared with RQD,the RQ index yields generally more favourable evaluations of slope rock mass integrity,although both methods classify the rock mass in tegrity of the mine slope predominantly as grade Ⅲ.

Microwave radiation technology,owing to its advantages of selective heating,instantaneous response,and volu metric heating,has shown broad application prospects in mineral processing and geotechnical engineering.This study systemati cally investigated the thermodynamic responses and damage evolution characteristics of 11 common rock-forming minerals and 8 types of rocks with different mineral compositions under microwave irradiation.Microwave irradiation experiments were conduc ted at powers of 0.5 kW and 1.0 kW for a duration of 3 minutes,combined with high-resolution CT scanning and three-dimen sional reconstruction techniques,to analyze the temperature rise behavior and internal damage evolution of minerals and rocks. The results indicate that,based on their microwave heating effects,minerals can be classified into three sensitivity types-high, medium,and low-among which hematite exhibits the strongest microwave absorption capacity.The temperature rise behavior of rocks is significantly controlled by their mineral composition;a higher content of highly sensitive minerals leads to greater heat ing rates and final temperature increments.CT images reveal that microwave-induced damage originates from localized thermal stress concentration caused by dielectric heterogeneity among minerals,and the damage patterns are regulated by the spatial distribution of highly sensitive minerals.These findings deepen the understanding of mineral-microwave interaction mechanisms and provide a theoretical basis for parameter optimization and engineering application of microwave-assisted rock-breaking tech nology.

Based on the principle of the hollow inclusion stress relief method and the confining pressure calibration test, the error caused by borehole eccentricity was analyzed.The eccentric core in the confining pressure test is regarded as an ec centric circular ring compression model on a plane.The bipolar coordinate method is used to derive the stress distribution cal culation formula for this model,and the distribution laws and characteristics of the tangential stress on the inner wall of the small hole under different confining pressures and eccentricities are analyzed through examples.On this basis,combined with the layout angle of the strain rosette in the hollow inclusion and the confining pressure calibration formula,a correction method for the measured rock elastic modulus under eccentricity is proposed.Using the field measured in-situ stress data,the rock elas tic modulus,k coefficient,ground stress components,and principal stresses at each measuring point before and after considering eccentricity are obtained.The results show that:① With increasing eccentricity,the error in the rock elastic modulus deter mined by subsequent confining pressure gradually increases,reaching a maximum of 13.41%;② The influence of eccentricity on the k coefficient,principal stress direction,and inclination angle at each measuring point is very small and can be neglected. ③ Borehole eccentricity has a significant influence on the magnitudes of ground stress components and principal stresses;the errors of the average maximum,intermediate,and minimum principal stresses at the three measuring points are 4.23%,4.19% and 4.24%,respectively,which should not be ignored in practical in-situ stress measurement work.

Pre-stressed anchor rods,existing in complex underground environments for long periods,experience perform ance degradation due to long-term tensile stress and corrosion infiltration.While existing research often focuses on the corrosion of anchor rods under pure environmental factors,there is relatively little analysis on the degradation of mechanical properties under the coupling of stress and corrosive media.This study selects commonly used HRB400 threaded steel anchor rods in en gineering as the research object,using the C-ring method constant deformation test to explore the morphological failure charac teristics of anchor rod materials under stress-corrosion environments.Additionally,using independently developed stress-corro sion test equipment,the degradation law of the tensile performance of anchor rods under constant prestress and chloride corro sion is investigated.Furthermore,combined with numerical analysis,the study further explores the impact of long-term chloride corrosion environments on the pre-stressed anchor rods for slope support and slope stability.The research results show that in chloride corrosion environments,the surface of the anchor rod body exhibits small cracks and pitting corrosion,with localized accelerated corrosion areas.With the passage of time or the increase of stress,these corrosion pits become more pronounced. Under the combined action of constant prestress and chloride corrosion,although the tensile strength of the anchor rod is slight ly reduced,it still meets the specification requirements.However,it is worth noting that the elongation of the anchor rod body after tensioning decreases significantly,approaching the lower limit specified in the standards.Through numerical simulation a nalysis,it is found that the degradation of the mechanical properties of the anchor rod leads to an increase in slope displace ment,tension failure at the top of the slope,and gradual expansion of the shear failure zone.With the increasing degree of cor rosion,a slip-through surface may form,significantly reducing the stability of the slope.

The underground support structure is frequently subjected to harsh conditions including high temperature,high humidity,and chemical erosion,which lead to recurrent corrosion failures and pose a significant threat to the stability of road way surrounding rock.To investigate the damage evolution law of mine pipe-seam anchor bolts in corrosive environments,indoor salt-spray accelerated corrosion tests and mechanical property tests were conducted to examine the effects of different tempera tures (30,35,40 ℃) and pH values (3,4,5) on the corrosion damage of the bolts,with particular focus on the apparent cor rosion characteristics,mass loss rate,corrosion rate,and fracture load loss.The test results show that:① Both the corrosion rate and the degree of mechanical property degradation decrease gradually with increasing pH value.The corrosion rate and fracture load loss rate at pH=3 are 1.24 times and 2.5 times those at pH=5,respectively.② The influence of temperature on the mass loss rate and fracture load loss rate is not consistent:the mass loss rate increases monotonically with rising temperature,whereas the fracture load loss is most severe at 35 ℃.③ At pH=3,the effects of 30 ℃ and 40 ℃ on the mechanical properties are not notably different,and 35 ℃ results in only 1.3 times the fracture load loss of the other two temperatures;thus,the acidic envi ronment is the dominant factor controlling corrosion.However,as the acidity weakens,the effect of temperature variation on fracture load loss becomes more pronounced.

To address the issue that sodium oleate (NaOL),an anionic collector commonly used in reverse flotation,suf fers from poor solubility and limited collecting performance at low temperatures due to its long carbon chain,which necessitates maintaining pulp temperature ≥35 ℃ in industrial flotation and significantly increases energy consumption,this study proposes a blending strategy of short-chain sodium decanoate (NaD) with NaOL to improve low-temperature flotation efficiency through molecular synergistic effects.The effects of combined collector ratio,pH value,and depressant dosage on the flotation behaviors of magnetite and quartz were systematically investigated at 10 ℃.The results show that at a NaOL-to-NaD molar ratio of 8∶2 and a total dosage of 20 mg/L,the quartz recovery reaches 91.12% in single-mineral flotation,while the magnetite recovery is only about 4.46%,indicating a significant difference in floatability between the two minerals.Based on these conditions,flota tion separation tests on artificially mixed ore (magnetite-to-quartz mass ratio of 3∶2) were conducted,yielding a concentrate with iron grade of 64.64% and recovery of 98.63%,which are respectively 12.24 percentage points and 8.86 percentage points higher than those obtained with NaOL alone under the same conditions,achieving efficient separation of magnetite and quartz.Zeta potential,contact angle,Fourier-transform infrared (FTIR) spectroscopy,and atomic force microscopy (AFM) an alyses reveal that NaOL and NaD undergo synergistic co-adsorption on the quartz surface,where NaD fills the gaps among NaOL clusters to form a dense and uniform mixed adsorption layer,significantly enhancing the surface hydrophobicity and re ducing the surface potential of quartz,thereby improving the collecting selectivity at low temperature.This study effectively o vercomes the low-temperature adaptability issue of fatty acid collectors through a molecular structure complementarity strategy, providing a new approach to reduce costs and improve efficiency in low-temperature flotation processes.

To address the difficulty in separating zinc minerals from calcite in a high-calcium,low-grade zinc oxide ore from Yunnan,flotation tests were conducted based on process mineralogy studies,using sodium carbonate as a dispersant,sodi um sulfide as a sulfidizing agent,sodium hexametaphosphate as a depressant,and a cationic-anionic combined collector com posed of modified oxygen-containing amine KOX-3 and phosphonic acid-containing anion KX-2.The ore contains Zn of 5.56% with an oxidation rate of about 91%;The main valuable minerals are smithsonite and hemimorphite,while the gangue is predominantly calcite (51.65%).Condition tests determined the optimal reagent regime as:Na2 CO3 of 3 000 g/t,Na2 S of 10 kg/t,sodium hexametaphosphate of 1 000 g/t,KOX-3 of 500 g/t,and KX-2 of 100 g/t.Under a grinding fineness of 80% passing 0.074 mm,a closed-circuit flowsheet was adopted,in which the rougher 1 concentrate was cleaned twice (with the cleaner 1 middlings returned to rougher 2),and the rougher 1 tailings were subjected to one roughing,two scavenging,and three cleaning stages;The two concentrate streams were combined to yield a final zinc concentrate with a grade of 22.87% Zn and a recovery of 80.35%.The results indicate that this flotation scheme with the cationic-anionic combined collector features a simple reagent regime and a well-structured flowsheet,effectively achieving separation of zinc minerals from calcite. It can provide a technical reference for the efficient recovery of similar high-calcium zinc oxide ores,and is of practical significance for unlocking the potential of complex refractory zinc oxide resources in China and reducing external dependence on zinc.

A mixed copper ore from abroad contains 1.45% Cu and 17.62 g/t associated Ag.The on-site flotation per formance is unsatisfactory due to the conflict between mechanical entrainment of slime and precise control of sulfidizer dosage. In this study,based on process mineralogy analysis,the reagent regime was optimized and circuit condition tests were carried out to determine suitable beneficiation parameters.The results show that using a closed-circuit process of "rough grinding,bulk flotation,rougher concentrate regrinding and cleaning",under the conditions of rough grinding fineness of 75% passing 0.074 mm,sodium silicate dosage of 600 g/t,combined collector of butyl xanthate and Z-200 at 60 + 30 g/t,and regrinding fineness of 88% passing 0.074 mm,a copper concentrate with yield of 3.89%,Cu grade of 33.19%,Cu recovery of 89.04%,and Ag grade of 337.08 g/t with Ag recovery of 74.42% in the concentrate can be obtained. In the tailings,Cu grade is reduced to 0.17% with a loss rate of 10.96%,and Ag grade is 4.69 g/t with a loss rate of 25.58%.The lost copper is mainly in the form of copper oxide (accounting for 52.94%).The experimental results provide a basis for efficient utilization of this ore resource and for plant process modification.

A lead-zinc sulfide ore from Sichuan is a low-grade,high-calcium refractory ore,with lead and zinc grades of 1.41% and 8.12%,Respectively;Lead and zinc mainly occur as sulfides.Due to the low lead grade and high content of calci um-bearing gangue minerals,conventional flotation cannot achieve effective separation and recovery of lead and zinc.To achieve efficient development and utilization of this ore,flotation separation tests were carried out.A preferential flotation process was a dopted,with self-developed YTH as the collector and zinc sulfate and sodium sulfite as combined depressants.The process flowsheet and reagent regime were determined through flotation condition tests.The results showed that a full-process closed circuit test using the flowsheet of "preferential lead flotation and zinc flotation from lead flotation tailings",in which both lead and zinc flotation adopted one roughing,one scavenging,and three cleaning stages,yielded a lead concentrate with a lead grade of 63.57%,a lead recovery of 75.52%,and a calcium content of 0.19%,as well as a zinc concentrate with a zinc grade of 57.37%,a zinc recovery of 73.62%,and a calcium content of 0.74%.This process achieved the effective development and u tilization of low-grade,high-calcium lead-zinc sulfide ore and can provide guidance for the industrial production of similar ores.

To further improve the iron grade of a titanium-bearing iron concentrate in the Panxi area,a process mineralo gy and fine grinding-magnetic separation experimental study was conducted.Through analysis of mineral dissemination charac teristics and element occurrence states,the mineralogical factors affecting concentrate upgrading were clarified,and the feasibil ity of fine grinding for upgrading was evaluated.The results show that the sample has a TFe grade of 41.59% and a TiO2 con tent of 10.84%.The main valuable minerals are titanomagnetite and ilmenite,while the gangue minerals are mainly pyroxene, chlorite,kaersutite,hornblende,and plagioclase. Iron is mainly hosted in magnetic iron minerals,with a distribution rate of 90.12%;Titanium is mainly distributed in titanomagnetite and ilmenite,among which the TiO2 distribution rate in titanomagne tite is 65.59%.Titanomagnetite,ilmenite,and sphene are mainly finely disseminated and closely intergrown with gangue miner als.The liberation degree of titanomagnetite is only 36.12%,which is the main factor limiting the improvement of iron concen trate grade.After grinding the material to 90% passing 45 μm using a horizontal stirred mill,the mineral liberation was signifi cantly improved. Through two-stage magnetic separation,a magnetic concentrate with a yield of 78. 06%,TFe grade of 50.90%,and TFe recovery of 95.54% was obtained,and the contents of gangue components such as SiO2 ,MgO,Al2 O3 ,and CaO in the concentrate were significantly reduced.The results indicate that the fine grinding and multi-stage magnetic separa tion process can effectively upgrade and reduce impurities in titanomagnetite concentrate.This study provides a technical refer ence for the deep upgrading of vanadium-titanium magnetite concentrate in the Panxi area.

In view of the high-silicon and high-calcium characteristics of a stockpiled magnesite ore from Dashiqiao, Yingkou,a systematic process mineralogy study was conducted using X-ray diffraction (XRD),X-ray fluorescence (XRF),and Automatic Mineral Identification and Characterization System (AMICS).The chemical composition,mineral composition,tex ture and structure,dissemination characteristics,liberation degree,intergrowth characteristics,and particle size distribution of the ore were analyzed to provide guidance for subsequent beneficiation and purification.The results show that the ore contains 95.69% MgO,1.89% CaO,and 1.72% SiO2 ,indicating a high-silicon and high-calcium magnesite.Calcium predominantly oc curs in dolomite,while silicon is distributed in pyrope,quartz,amphibole,and clinochlore.Magnesite is mainly in liberated form,accounting for 95.98%,with a cumulative liberation degree of 97.38% at the level above 90%,and has a relatively coarse particle size (73.45% above 74 μm).Gangue minerals mostly occur as fine-grained disseminated inclusions,closely in tergrown with magnesite,and are prone to sliming.The diversity and varying floatability of silicon-bearing gangue minerals cause difficulties in desilication by flotation;Moreover,the similar physicochemical properties and crystal structures of dolomite and magnesite make their flotation separation challenging.Based on the process mineralogy results,a preliminary flotation test using a rough grinding,desliming and single reverse flotation flowsheet was carried out,yielding a magnesite concentrate with 97.91% MgO,0.17% SiO2 ,and 1.54% CaO.The findings can provide a basis for the subsequent optimization of flotation con ditions.

To address the problem that physical beneficiation can hardly remove minerals on particle surfaces,inclusions, and impurities within the crystal lattice during the preparation of quartz sand from quartz sandstone,quartz sandstone from a certain area in Hebei with a SiO2 content of 98.07% was used as the raw material.After pretreatment by crushing,grinding classification,and magnetic separation to a particle size of 0.212~0.106 mm,a quartz sand flotation concentrate with a SiO2 content of 99.67% was obtained by flotation purification.The purification effect under the synergistic action of acid leaching and chlorination roasting was systematically studied.The results show that during acid leaching,hydrofluoric acid made a prom inent contribution to impurity removal.When 0.8 mol/L hydrofluoric acid and 4 mol/L phosphoric acid were mixed at a volume ratio of 1∶1 and used for leaching at 80 ℃ for 4 h,the removal rates of Al,Fe,and Ti reached 85.28%,67.64%,and 16.75%,respectively.To further improve the purification efficiency,chlorination roasting was introduced.Quartz sand was mixed with 3% sodium chloride and subjected to chlorination roasting at 900 ℃ for 4 h,and a process system of "acid leaching pretreatment (primary acid leaching)-chlorination roasting-secondary acid leaching" was established.Finally,the removal rates of Al,Fe,and Ti increased to 89.86%,79.43%,and 56.18%,respectively;The SiO2 content of the quartz sand increased from 99.670% to 99.979%,and the total impurity content decreased to 212.1 mg/kg.This study reveals the synergistic mechanism of acid chemical etching and chlorination roasting on impurity migration/replacement and surface dissolution-mediated removal in quartz,providing an efficient and feasible process route for purifying quartz sandstone to prepare high-purity quartz sand.

To achieve the green and efficient comprehensive recovery of quartz and feldspar from lepidolite flotation tail ings,this study systematically conducted process mineralogical analysis and fluorine-free weak-acid flotation tests on a lepido lite flotation tailing sample from Jiangxi Province.Process mineralogical analysis shows that the tailings contain 77.1% SiO2 and 6.9% Na2 O+K2 O,with quartz,albite,and potassium feldspar accounting for 35.3%,44.5%,and 17.8%,respectively.The total proportion of quartz and feldspar exceeds 97%,indicating high comprehensive recovery value.Flotation test results demon strate that using the self-developed cationic collector WIT-1 under the conditions of a grinding fineness of -0.074 mm account ing for 50%,pulp pH of 4.5,WIT-1 dosage of 2.4 kg/t,and sodium hexametaphosphate dosage of 2.2 kg/t,a one-stage roug her and seven-stage scavenger reverse flotation circuit can yield a high-purity quartz product with a SiO2 grade of 99.8% and a feldspar product with a Na2 O+K2 O grade exceeding 9%.This method effectively avoids the equipment corrosion and environ mental pollution issues associated with traditional hydrofluoric acid activation and strong-acid flotation methods,providing a fea sible technical pathway for the green and efficient utilization of lepidolite flotation tailings.

To establish an evaluation method for the grindability of tower mills and enable effective prediction of their specific energy consumption,this study took an Anshan-type magnetite ore as the research object and,based on a modified Hardgrove grindability test,proposed a test method for characterizing the grinding performance of tower mills.Samples of two size fractions,-3 mm and -1 mm,were each divided into four narrow size fractions and ground using a Hardgrove grindability tester,with different rotation numbers representing different input energy levels.Mathematical models relating the grinding product t4 to specific energy consumption for each narrow size fraction were constructed based on the A×b breakage model and the fmat breakage model,respectively,and the model parameters under the two feed sizes were fitted.The prediction results were then verified through laboratory tower mill grinding tests.The results show that when fitted with the A×b model,the A×b values for the -3 mm and -1 mm feeds are 16.72 and 11.53,respectively;When fitted with the fmat model,the corresponding ore hardness indices SMi are 4.78 and 3.88,indicating that the finer the feed size,the lower the shear grindability.The SMi values obtained from the fmat model were used to predict the theoretical specific energy consumption of the tower mill,and the coeffi cient of determination R2 between the predicted and actual maximum specific energy consumption reached 0.98.This method can effectively evaluate the grindability of materials in tower mills and provide a reliable basis for predicting the useful specific energy consumption of tower mills.

Proper cavability is a prerequisite for successful application of block caving in hard rock mines,but the high uniaxial compressive strength and the lack of developed joint cracks limit the initial and continuous caving of the rock mass.In order to explore the mechanism of the effect of blasting parameters on the pre-conditioning of hard rock by block caving,numer ical simulations were conducted based on Box-Behnken Design to investigate the effects of various factors such as borehole ap erture,uncoupling coefficient,and borehole spacing on indicators such as central crack length,crack rate,and crushing area ra dius.The expansion indicators of blasting cracks were optimized based on response surface methodology analysis and satisfac tion function optimization.The results show that the decouple coefficient is the main factor affecting the radius of the blasting fragmentation area.The decouple coefficient and the distance between blast holes have a more significant impact on the expan sion effect of blasting cracks,and are the main factors affecting the weakening area.The decouple coefficient is the main factor affecting the radius of the fragmentation area.When the borehole diameter and decouple coefficient are at a low coding level, the length of the central crack is larger.When the decouple coefficient and borehole aperture are both at a high coding level, the fracture rate generated after blasting is higher.However,when the borehole diameter is at a low coding level,the change in decouple coefficient has a more significant impact on the radius of the crushing area.The optimized blasting parameters using multi-objective optimization for hard rock are borehole diameter 165 mm,decouple coefficient 1.35,borehole spacing 10 m, with an overall optimal satisfaction function value of 0.904 6.The verification experiment shows that deep hole blasting can ef fectively improve the cavability and pre-conditioning effect of hard rock block caving.

To address the challenges of strong adhesion,high inter-object similarity,and poor image quality in open-pit mine blast pile orerock images,conventional segmentation methods often yield low accuracy and unsatisfactory results.To this end,we introduce an attention mechanism into the traditional U-Net framework and propose an attention optimized CAU-Net method for segmenting blast pile ore-rock images.The proposed architecture retains U-Net as the backbone and incorporates at tention modules before each convolutional learning stage.Comparative segmentation experiments are conducted against three at tention models.The results show that the CAU-Net model significantly improves segmentation performance,achieving an accu racy (ACC) of 94.08% and an AUC (Area Under Curve) of 97.43%,indicating strong predictive capability.Further compar isons with threshold-based segmentation and the standard U-Net,together with evaluation using the Intersection over Union (IoU) metric,confirm that the proposed method can segment blast pile ore-rock images more accurately.The high-precision segmentation results,when applied to digital ore-rock fragmentation statistics,substantially enhance statistical accuracy and ef fectively advance the digitalization of mining operations.

During the operation of unmanned electric locomotives in underground mines,potential collision objects such as personnel,ore,and equipment frequently appear,posing significant safety hazards to production and transportation.To miti gate such risks,the YOLOv7 model was selected for collision object identification with reference to similar cases.However,de tection results indicated that the YOLOv7 model suffered from issues in detection region partitioning and collision object feature extraction within the underground environment,leading to frequent missed and false detections.To address these deficiencies, the YOLOv7 model was improved by incorporating the SimAM attention mechanism to assist in detection region division and by replacing the original CIoU loss function with the EIoU loss function to enhance feature extraction capability.Experimental re sults demonstrate that the improved YOLOv7 model achieves a mean Average Precision (mAP) of 98.41%,which is 4.62 per centage points higher than that of the original YOLOv7 model,and the frame rate (Frames Per Second,FPS) is increased by 8 frames per second.Moreover,the precision and recall for detecting various types of collision objects are significantly improved. The enhanced model can effectively satisfy the requirements for potential collision detection in unmanned underground locomo tive operations,thereby providing technical support for the realization of fully autonomous underground haulage.

To address the problems of blurred boundaries of hot-spot targets,complex temperature gradient variations,and large differences in target scales in infrared image object detection for electrical equipment in mining-area substations,existing detection algorithms generally have deficiencies such as insufficient recognition accuracy and high missed detection rates.By comparing the performance of several mainstream object detection algorithms on an infrared image dataset of electrical equip ment in mining-area substations,it is found that the Faster R-CNN algorithm incorporating a feature pyramid structure performs relatively well,but its recognition performance of small hot-spot targets and temperature anomaly regions still has room for im provement.Therefore,an improved Faster R-CNN algorithm is proposed.First,a spatial pyramid pooling structure is introduced into the network to extract multi-scale features.Second,the feature fusion method is optimized to enhance the network′s percep tion of targets at different scales.In the region proposal generation stage,the quality of region proposals is improved by expan ding anchor scales and aspect ratios.Finally,the classification and bounding box regression loss functions are improved to en hance detection accuracy.Experimental results show that,compared with the original Faster R-CNN algorithm,the improved al gorithm achieves improvements of 2.7 percentage points in AP(0.5∶0.95),4.3 percentage points in AP(0.5),and 1.8 per centage points in the detection accuracy for small-sized hot-spot targets on the infrared image dataset of electrical equipment in mining-area substations,reflecting that the improved algorithm has certain applicability to infrared detection of mining-area e lectrical equipment.

The accuracy and efficiency of coal-gangue identification are not only critical supports for clean coal utiliza tion,but also key components of the core technology for intelligent coal-rock recognition in the construction of intelligent mines.Owing to the prominent advantages of infrared thermography,such as high recognition precision,low susceptibility to op erational environmental interference,simple operation,and low cost,samples of bituminous coal and roof sandstone were collect ed from the 2067 fully mechanized working face in Dongpang Mine.Active thermal excitation was adopted to obtain the thermal infrared response information of coal and gangue,and the thermal excitation temperature change index was quantitatively calcu lated to achieve effective discrimination between the two materials.Accordingly,a coal-gangue identification method for belt conveyor transportation was proposed.The experimental results indicate that during both heating and cooling stages of thermal excitation,the thermal radiation temperatures of bituminous coal and roof sandstone exhibit significant variations,and the infra red response characteristics of coal and gangue show distinct differences,with the temperature variation amplitude of bituminous coal being notably larger than that of sandstone.Based on the evolution of radiation temperature with time under thermal excita tion,the thermal excitation temperature change index was introduced,and its applicable conditions were clarified.Under the ex perimental conditions employing a specific heat source for active heating and cooling excitation,the threshold for distinguishing bituminous coal from roof sandstone was established and verified experimentally.Meanwhile,in view of the low illumination and high dust concentration in underground mines,a coal-gangue recognition scheme was proposed,which involves arranging a puri fication constant-temperature regulation zone,a heating zone,a coal-gangue recognition monitoring zone,and a sorting zone on the belt conveyor.This provides a new technical approach for intelligent coal-gangue recognition in mining operations.

Based on the Fluent platform,a three-dimensional transient numerical simulation of the gas-liquid two-phase flow in a bubble generator with and without a static mixer was performed under inlet pressures of 0.1 and 0.2 MPa using the Eulerian-Eulerian two-fluid model and the Realizable k-ε turbulence model.The mesh for the model without the mixer was ap proximately 90 000 cells,and it increased to approximately 420 000 after adding the static mixer.The pressure-velocity cou pling was handled by the SIMPLE algorithm,and the steady-state results were extracted after the residuals and monitored pa rameters became stable.The results show that increasing the inlet pressure significantly increases the maximum liquid velocity at the throat and enhances the flow driving force,but the pump power requirement and energy consumption also increase.The static mixer can effectively improve the uniformity of gas phase distribution in the oscillation chamber.Under an inlet pressure of 0.1 MPa,the cross-sectional average gas holdup for the case with the mixer is close to that for the case without the mixer at 0.2 MPa.Meanwhile,the axial pressure gradient becomes flatter,indicating that the static mixer helps reduce flow energy loss. In summary,the static mixer can improve the gas-liquid distribution and flow structure and has reference value for the energy saving and performance optimization of bubble generators.

The underground excavation face has the characteristics of concentrated production equipment,large amount of dust production and complex wind flow field,which seriously threatens the safety of the mine production and the occupational health of the miners.At present,the widely used dry-type dust collection method has a high purification efficiency for dust,es pecially for respirable dust.However,issues such as high operating resistance and poor dust extraction efficiency exist during its usage.To this end,the KCG-800 dry-type dust collection system was designed for the W3306 auxiliary transportation along the groove of the high-gas excavation roadway of Shanxi Gaohe Energy Co.,Ltd.and the combination of positive and negative pres sure air ducts was used to regulate the flow of dust-containing air in the roadway.The positive pressure air duct and the nega tive pressure air duct were set up 4 m and 3 m away from the head of the excavation face respectively.And a round table shaped dust collection cover was selected to be set at the entrance of the negative pressure air duct.The field application results show that the average dust removal efficiency of the total dust and respirable dust at the position of the roadheader driver is 97.67% and 95.99%,respectively.The average dust removal efficiency of the total dust and respirable dust at the transfer point is 96.88% and 93.71%,respectively.And the average dust removal efficiency of the total dust and respirable dust at the outlet position of the fan is 96.26% and 98.62%,respectively.There is no obvious dust drifting phenomenon behind the road way.In addition,before and after the dust removal system was turned on,the gas concentration at the three measuring points on the site remains almost unchanged.And there was no gas accumulation,which proves the safety of the mine dry-type dust col lection system in the high-gas contained roadway.

Intelligent decision-making is the core research direction in the field of intelligent ventilation in mines,and the prerequisite for achieving intelligent decision-making is effective processing,analysis,and representation learning of data.In re sponse to the issues of low data utilization and insufficient knowledge reasoning capability in mine intelligent ventilation sys tems,this study constructs a knowledge ontology framework for mine ventilation based on the Coal Mine Safety Regulations (2022 Edition).It systematically evaluates the performance characteristics of knowledge representation learning models such as TransE,TransR,RESCAL,DistMult,and ComplEx,achieving vector representation and deep information mining of ventilation knowledge.By using loss functions and evaluation metrics,different dimensional knowledge representation methods were as sessed,determining that the TransE model has the optimal applicability in mine ventilation knowledge representation.Experi mental results show that the TransE model outperforms other models in terms of representation learning efficiency and accura cy,exhibiting a lower average loss value during the representation learning process,with similar ventilation entities showing sig nificant clustering characteristics in the vector space,and optimal performance when the embedding vector is 40 dimensions. This model effectively represents ventilation knowledge,providing high-precision knowledge reasoning support for intelligent de cision-making systems.

To scientifically evaluate landslide stability and formulate effective mitigation strategies,this study takes Qinzhou District,Tianshui City as the research object.Based on the analysis of regional geomorphology and landslide develop ment characteristics,ten indicators:geological structure,disaster frequency,slope gradient and gradient change rate,slope as pect and shape change rate,elevation,gully density,vegetation index,rainfall,earthquake,and human activity were selected. The Analytic Hierarchy Process (AHP) was used to determine their weights,and GIS spatial analysis was combined to conduct a comprehensive evaluation of landslide susceptibility,vulnerability,and hazard.The results show that landslides in Qinzhou District are dominated by loess landslides and loess-mudstone landslides.Five high-hazard zones,two medium-hazard zones, and three low-hazard zones were identified.The high-hazard zones cover about 1,163. 1 km2,contain 158 hidden danger points,making them key areas for disaster prevention and mitigation.On this basis,a comprehensive mitigation strategy featu ring "management first,technical support,and combined prevention and control" was proposed.In high-hazard zones,measures combining monitoring and early warning,drainage and load reduction,retaining reinforcement,and ecological restoration were a dopted.A typical slope in the Taijing-Yuquan high-hazard subzone was selected for six-month deep displacement monitoring. The cumulative displacements of five inclinometer holes ranged from 12.4 mm to 30.6 mm,all below the 50 mm early-warning threshold,indicating coordinated deformation and overall stability of the slope.The study demonstrates that the proposed mitiga tion strategy is technically feasible and practical,and can provide a scientific basis for landslide risk control and territorial spa tial planning in Qinzhou District and similar areas.

To address the issues of high feature dimensionality,high computational complexity,empirical dependence in parameter selection,and insufficient generalization ability in mine floor water inrush prediction,a prediction model based on Principal Component Analysis (PCA) and Fruit Fly Optimization Algorithm (FOA) improved Support Vector Classification (SVC),namely the PCA-FOA-SVC model,is proposed.First,PCA is used to reduce the dimensionality of the multi-factor in fluencing data of floor water inrush.Then,FOA is employed to adaptively and globally optimize the penalty factor and kernel function parameters of SVC.Finally,the optimized SVC is utilized to construct the optimal classification hyperplane for binary classification prediction of floor water inrush conditions.Public data extracted from published academic papers were used as the test set.The test results show that after algorithm optimization,the classification accuracy increases from 79.8% to 98.6%,and when the algorithm reaches the optimal fitness value,the iteration number is only 17,with a root mean square error as low as 0.021.These results verify the effectiveness of PCA and FOA in improving SVC.Further model testing indicates that the predic tion accuracy reaches 98.31%,and the prediction time is only 5.24 s,significantly outperforming other comparison models.This model can provide effective technical support for early warning and safety prevention of coal mine floor water inrush disasters.

In mining tunnels and urban subway engineering,a large number of pipeline facilities are installed along the axial direction.During mobile laser scanning,due to scanning angles,structural occlusions,and sensor placement constraints, point clouds on the back-facing side of pipelines are often difficult to capture,resulting in missing arc segments of the cylindri cal structure.This further degrades the completeness and accuracy of 3D reconstruction.To address this issue,this paper propo ses a local feature-based geometric fitting method for point cloud completion of pipelines.First,local structural features of pipe line point clouds are analyzed to extract stable geometric parameters.Then,based on the geometric constraints of cylindrical structures,local fitting and point cloud reconstruction are performed in missing regions,enabling continuous recovery of the pipeline surface.Experiments are conducted on point cloud data of subway tunnel pipelines and mine ventilation ducts.The re sults demonstrate that the proposed method can effectively complete missing back-facing regions and local holes.The recon structed point clouds smoothly connect with the original data and accurately recover the complete cylindrical geometry.Moreo ver,the method does not rely on large-scale training data and shows strong adaptability and robustness.

The adjustment of underground traverse control network and the prediction of holing-through survey errors are the core knowledge modules of the course Mining Surveying,and the abstraction of their theoretical framework and the complex ity of their technical methods pose dual challenges to both classroom and practical teaching.In order to improve the teaching quality of mining surveying courses and help students better understand the basic theory of mining surveying data processing,a mining surveying data processing simulation-based teaching system was developed using MATLAB,integrating mining surveying data processing theories and methods with actual mine observation data.The system is mainly divided into two modules: ① MATLAB-based underground traverse control network adjustment simulation module.According to the characteristics of un derground traverse control network and combined with actual measurement data,a simulation of adjustment of underground trav erse control network with additional gyroscopic orientation edges was implemented through MATLAB.② A simulation module for predicting holing-through survey errors based on MATLAB GUI.It mainly includes four sub-modules for holing-through sur vey error prediction:simulation of the principle of holing-through survey error prediction,simulation of point-position error dis play,simulation of the optimal position of gyroscopic orientation edges,and simulation of the optimal scheme selection for ho ling-through survey.The system is easy to operate and has a clear structure.By combining actual case data from mining survey ing,students can better understand the principles and methods of data processing in mining surveying,as well as carry out inno vative tests such as solving the optimal scheme for the number and position of gyroscopic orientation edges.This can cultivate students′ learning interest and craftsmanship spirit,thereby effectively improving the teaching effectiveness and quality of the course Mining Surveying.

To improve the grouting effectiveness in fractured rock masses of ultra-deep shafts and address the perform ance deficiencies of conventional grouting materials in water sealing and surrounding rock reinforcement,superfine cement was selected as the base material.The orthogonal tests and range analysis were used to investigate the effects of silica fume,fly ash, ultrafine ground granulated blast-furnace slag,and superplasticizer dosages on the fluidity,bleeding rate,setting time,and com pressive strength of superfine cement grout.The results indicate that fly ash exhibits the most significant influence on fluidity, bleeding rate,and compressive strength,while silica fume predominantly improves the setting time.The effects of ultrafine slag and superplasticizer are relatively minor.The combined use of multiple admixtures demonstrates complementary effects on grout performance,enabling synergistic optimization of fluidity,stability,and mechanical properties.Considering the priority order of compressive strength,setting time,fluidity,and bleeding rate,the optimum mix proportion was determined as 12% silica fume, 30% fly ash,20% ultrafine slag,and 0.15% superplasticizer by mass of cement.Field application shows that the water inflow of a single borehole was reduced to below 2 m3 /h after grouting,with a water sealing rate of 90%,confirming the favorable ap plicability and engineering effectiveness of the modified superfine cement grouting material in fractured rock mass grouting.

Based on the similarity between high-alumina ladle slag (LF) and calcium aluminate cement,this study pro poses its utilization as a rapid-setting admixture for the design and preparation of temporary support materials in mining engi neering.A systematic investigation was conducted to examine its influence on the hydration process and macroscopic properties of ordinary Portland cement.The results demonstrate that the incorporation of high-alumina ladle slag (LF) significantly modu lates the setting and hardening behavior of the system.As its dosage increases,the setting time of the cement paste is markedly shortened,while the compressive strength of the cement mortar generally shows a declining trend across all tested ages.At lower incorporation levels (≤10%),the hydration process remains dominated by the Portland cement components.The calcium alu minate phases present in the slag are activated by calcium hydroxide and gypsum,accelerating the reaction kinetics and advan cing the hydration acceleration period,thereby reducing the setting time to meet the rapid-response requirements for temporary support.At higher dosages (≥15%),the early hydration becomes governed by the calcium aluminate minerals.Gypsum is rap idly consumed,leading to the fast formation of substantial hydration products such as ettringite,which induces flash setting and rapid hardening.Under these conditions,Portland clinker particles become encapsulated,significantly prolonging their hydration induction period and consequently restricting later strength development.This study elucidates the mechanistic role and per formance evolution of high-alumina ladle slag (LF) as a functional admixture at varying dosages,providing a theoretical foun dation for the development of mining-specific temporary support materials based on industrial solid wastes.