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    25 October 2025, Volume 41 Issue 10
    Previous Issue   
    Research on Stability Analysis and Prevention and Control Technology of Shaft under Acidic Water Corrosion Condition
    HUANG Lin SUN Bo, GUO Wei,
    2025, 41(10):  1-6，11. 
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    In view of the current situation of frequent corrosion of acid groundwater in mine shafts and roadways，taking a mixed well of a sulfur gold mine in Anhui Province as the engineering background，the current situation of acid water corrosion in mixed wells is investigated by means of field investigation，theo⁃ retical analysis and numerical simulation. The weakening mechanism of concrete strength under acid corro⁃ sion conditions is revealed，the stability of shaft under acid corrosion conditions is studied，and the preven⁃ tion and control countermeasures are put forward. The results show that the acid gushing water in the well⁃ bore comes from the accumulated water in the old goaf of the surrounding sulfide mine. The residual sulfide minerals in the goaf interact with oxygen and water to generate acid water，which is laterally supplied to the wellbore through water sources such as rock fissures. There are abnormal changes in rock movement，stress and plastic zone distribution within -168 ~ -270 m and -495 ~ -575 m in the wellbore，with poor stability and great potential safety hazards. In order to enhance the stability of the wellbore and ensure the production safety of the wellbore，the comprehensive prevention and control measures of reducing acid water gushing， increasing the comprehensive strength of surrounding rock and strengthening inspection and maintenance are put forward.
    Research on Support Technology of Roadway Surrounding Rock under the Influence of Dynamic Pressure in a Mine
    KONG Lingda
    2025, 41(10):  7-11. 
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    The upper part of 2501 transportation gateway in a mine in Shanxi is 2303 mining face. The dynamic pressure caused by the collapse of the upper mining face leads to serious deformation of the lower roadway and instability of the surrounding rock，which brings significant influence to the safe mining of coal in the working face. In order to solve the above problems，combined with the field conditions of the transpor⁃ tation roadway，the numerical simulation is used to study the strain evolution law of the surrounding rock of the roadway，and the technical scheme of the surrounding rock support of the dynamic pressure roadway is given. Numerical simulation is used to analyze the strain distribution of surrounding rock at 10，20，30，40 d. After 40 d，the surrounding rock and overlying rock mass of 2501 transport roadway are broken as a whole， and the original anchor and cable support measures could not meet the support strength requirements of dy⁃ namic pressure roadway. According to the results of numerical simulation，it is proposed to strengthen the roadway support by using the combination of pipe shed and U-shaped steel，so as to improve the strength of the surface protection and the deformation resistance of the surrounding rock. After the field application，the surrounding rock deformation control effect of 2501 transport crossheading is better，which can meet the needs of subsequent use. The research results and methods have certain guiding significance for other dy⁃ namic pressure roadway support.
    Mining Process and Support Technology for a Working Face Crossing Large Faults of No.7 Coal Mine
    LI Jie
    2025, 41(10):  12-16，22. 
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    During the period of the 11603 working face crossing large fault of the Dananhu No. 7 Coal Mine ，the rock breaking volume was large，the mining speed was slow，the equipment failure rate was high，and the surrounding rock in the advanced stress zone at the tail end was severely broken. The prob⁃ lems existing in the original mining process were analyzed，and the mining process was optimized. The "al⁃ ley method" mining process was implemented. Meanwhile，combined support such as "grouting + dense steel shed + pier column support" was implemented for the surrounding rock in the fault area. The practical application effect shows that after the optimization of the mining process，the rock breaking volume was re⁃ duced by 3 244 m3 ，the equipment failure rate was reduced to 6%，the maintenance cost was reduced by 249 000 yuan，and the mining speed was increased to 4.8 m/d. After optimizing the support of the surround⁃ ing rock in the fault area，the deformation of both sides of the surrounding rock in the advanced stress area was greater than the movement of the top and bottom slabs. The maximum movement of both sides was 0.16 m，the maximum settlement of the top slab was 0.1m，and the maximum bottom bulge was 0.13 m. The over⁃ all stability of the surrounding rock was good，and no accidents such as collapse of both sides or leakage of the bottom slab occurred.
    Research on Key Support Technology for Fractured Roof at the End of Multiple Stress Concentration Areas in Mining Face of Wangjialing Coal Mine
    SUN Guoqiang
    2025, 41(10):  17-22. 
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    During the mining period of the 18107 working face of Wangjialing Coal Mine，due to the influence of the adjacent 18105 working face's goaf，faults and syncline structure，when the mining reached the 900~950 m section，the roof of the working face at the tail end showed signs of fragmentation and leak⁃ age. According to the current mining situation of the working face，the causes of roof breakage and leakage were analyzed from several aspects such as internal stress of the coal body，geological structure，and end support. The "artificial false roof" support was adopted for the leakage area，and the combined support of "flexible grouting + pressure-reducing anchor cable + self-locking anchor bolt" was proposed for the break⁃ age area. Judging from the actual application effect on site，the expansion of the leakage area was controlled after the combined support was adopted. The working resistance of the support was increased to 95%，the collapse length of the coal pillar at the end was reduced to 1.2 m，the collapse depth was reduced to 0.7 m， the roof subsidence was reduced to 0.11 m，and the bottom bulge was reduced to 0.22 m，which achieved re⁃ markable application results.
    Optimization of Stope Span and Engineering Application for Sublevel Drilling and Stage Caving with Subsequent Backfilling Mining Method
    LI Yanfen, XIANG Weihua, LIAN Huanchao, WANG Sheguang, WANG Peiei, YANG Zhiqiang,
    2025, 41(10):  23-27. 
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    To optimize the stope width in the sublevel drilling and stage caving with subsequent back⁃ filling mining method at Zhongguan Iron Mine，and to achieve safe and efficient extraction of fractured and difficult-to-mine ore bodies，numerical simulations were conducted based on the optimized results of the stope's maximum allowable exposure dimensions derived from the Mathews stability graph method. Simula⁃ tions were performed for a stope height of 30 m and widths of 10，12，14，16，and 18 m. By comparing and analyzing the vertical stress on the stope roof，horizontal displacement of the side walls，and the develop⁃ ment of plastic zones under different width scenarios，the rational stope structural parameters were further determined. The results indicate that the stope remains stable when the width is no more than 10 m. When the width increases to 12 m，additional reinforcement of the central roof area is required to maintain stabili⁃ ty. For widths ranging from 14 to 18 m，stope stability is significantly compromised. Based on these find⁃ ings，engineering practice was implemented using the sublevel drilling and bench caving with delayed back⁃ filling mining method，with stope dimensions of 30 m in height，12 m in width，and a length not exceeding 50 m. A roof protection drift was constructed at the middle of the stope roof at the -200 m level. A combined pre-support technique using prestressed long cable bolts，mesh，and shotcrete was applied for proactive roof control. Field practice demonstrates that the stope achieves a production capacity of 3 170 t/d，with an ore recovery rate of 88.35%，a dilution rate of 10.17%，and excellent stope stability. This confirms the feasi⁃ bility of safe，efficient，and economical mining operations.
    Application of Fault Tree Analysis in the Hierarchical Risk Control of Stope Stability for Stage and Stope Subsequent Backfill Mining Method
    LIU Jinjun
    2025, 41(10):  28-34. 
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    With the advancement of green mine construction，the stage and stope subsequent backfill mining method has been widely applied in large-scale mines. This method employs cemented tailings to backfill goafs，effectively reducing geotechnical hazards such as rock bursts. However，due to its two-phase extraction process（primary and secondary stoping），the stability of stope surrounding rock is influenced by various complex factors. This leads to significant risks of deformation，damage，or even collapse in the sur⁃ rounding rock during mining operations，posing a major threat to safe production in large mines. To enhance the stability of stope surrounding rock in subsequent backfill mining and ensure safety during ore extraction， Fault Tree Analysis（FTA）was adopted. Starting from potential accident types caused by unstable stope rock mass，FTA enables a backward deduction of root causes. Evaluation units were categorized based on geological conditions，mining technology，and management factors to identify potential risk sources. Subse⁃ quently，the LEC semi-quantitative risk assessment method was used to determine risk levels. Targeted con⁃ trol measures were formulated and implemented to prevent risks from evolving into hazards or accidents. Fi⁃ nally，dynamic inspections were conducted to verify the implementation of these risk controls，enabling timely identification of emerging hazards due to control failures，followed by closed-loop corrective actions to prevent hazard-induced accidents. Practical application demonstrates that by using Fault Tree Analysis （FTA）to identify risks in stope stability control at their source and eliminating hazards through process man⁃agement，the safety management of stope production has successfully shifted from post-incident response to proactive，pre-emptive risk control in the stage and stope subsequent backfill mining method.
    Research on the Distribution Characteristics of Advanced Support Pressure in the Comprehensive Caving Working Face Due to Igneous Intrusion
    LIU Yuhang, ZHANG Ming,
    2025, 41(10):  35-39. 
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    In order to master the characteristics of mineral pressure manifestations in the comprehen⁃ sive caving working face under the special geological conditions of igneous intrusion, to ensure the rationali⁃ ty of the roadway support，the characteristics of coal body weakening under the influence of igneous rock in⁃ trusion were determined by testing the physical and mechanical parameters of surrounding rock. On this ba⁃ sis, the magnitude and influence range of the peak abutment pressure during mining under different working conditions were theoretically calculated. Furthermore, the control variable method was adopted to adjust the coal body parameters to build a three-dimensional numerical model before and after igneous rock intrusion, and the variation rules of vertical stress at different depths above the working face were clarified. The accura⁃ cy of the research results is verified by field measurement.The results show that the intrusion of igneous rock erodes the coal body, driving its structure from dense to soft and porous, resulting in a significant reduction in its physical and mechanical properties.The coal seam above the working face is easy to break under the in⁃ fluence of dynamic pressure, and the large longitudinal plastic failure depth leads to the common superposi⁃ tion of coal load, and the internal stress at a depth of 10 m above the overlying rock is at a high level.Com⁃ pared to conventional areas, the stress concentration coefficient and its influence range have significantly in⁃ creased. The combination of factors such as low coal body strength, high horizontal stress, softening of frac⁃ ture water, and extensive pre-supporting pressure led to the large-scale instability and collapse of the road⁃ way during the mining process.The research findings can serve as a reference for reasonably determining the advance support layout range for working faces under similar geological conditions.
    Research on the Influence of Section Parameters on Stability of Downward Mining Drift Roof
    KOU Yongyuan JIA Feng YANG Qingwei LI Zhengjie XU Lijie SHI Lang LI Shimin ZHANG Ming
    2025, 41(10):  40-45，50. 
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    To solve the problem of low resource recovery efficiency in the deep mining area of Jinch⁃ uan No.2 Mining area，numerical simulation was used to conduct research on the optimization of deep min⁃ ing drift parameters. Firstly，6 m × 4 m large section drift stope model and 5 m × 4 m conventional section drift stope model were established. Secondly，FLAC3D software was used to simulate the mining method of cemented backfilling with downward layered horizontal drift，and the stress values and deformation laws of large section and conventional section drift during the mining process were analyzed and studied. The re⁃ sults show that during the mining process，the maximum subsidence of the conventional section and en⁃ larged cross-section drift roof is 12.55 and 17.2 mm，respectively. And the maximum convergence displace⁃ ment values of the two sides are 12.28 and 21.56 mm，respectively. Compared to others，the displacement values of roof and two sides have increased after enlarging the cross-section，but the increase is not signifi⁃ cant，indicating that the rock movement in the surrounding area caused by the excavation of the two types of cross-section sizes is extremely close. Besides，the maximum compressive stresses in the vertical direc⁃ tion of the conventional section and enlarged cross-section drift roof are 0.389 1 and 0.457 8 MPa，respec⁃ tively. The maximum tensile stresses in the horizontal plane perpendicular to the direction of the drift are 0.254 2 and 0.297 8 MPa，respectively，which are lower than the ultimate tensile stress of the top plate of the backfill by 0.53 MPa. It can be seen from this that after enlarging the cross-section of the downward drift，the maximum tensile stress borne by the roof backfill increased by 17.2%，indicating that the width of
    the drift has a significant impact on the maximum tensile stress value of its false roof backfill，expanding the
    drift-sectional width of the panel to 6 m is reasonable and feasible.
    Research and Application on the Protective Rock Pillar Dimensions for Coal Uncovering at the Tunnel Face in Gas-outburst Prone Tunnels
    WANG Ding, YAN Zhenqian LIU Changwu YUAN Xun ZHAO Chao CHEN Xiaoqiang
    2025, 41(10):  46-50. 
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    In the coal uncovering construction of tunnels prone to coal and gas outbursts，scientifically determining the thickness of the protective rock pillar is a core technical challenge for preventing and con⁃ trolling dynamic disasters. To overcome the limitation of traditional empirical methods，which lack a quanti⁃ tative calculation basis，an analytical model based on the thin-plate theory of elasticity is established，com⁃ prehensively considering gas pressure，surrounding rock confinement effects，and the spatial geometric characteristics of the tunnel face (such as excavation width and height)，the differential equation governing the plate's bending is derived. An analytical formula for the required rock pillar thickness is then obtained using the maximum tensile stress criterion. Theoretical analysis reveals that the rock pillar thickness is lin⁃ early and positively correlated with gas pressure，nonlinearly and positively correlated with tunnel excava⁃ tion width and height，and negatively correlated with the uniaxial compressive strength of the surrounding rock，thereby elucidating its multi-factor coupling mechanism. Field validation at the Baoding 2# Tunnel demonstrated that the theoretically calculated thickness of 3.44 m is 9.2% greater than the measured value of 3.15 m，with the error well within the acceptable engineering range (≤10%). The conservative nature of the theoretical value effectively provides a safety factor of 1.12，satisfying the requirements stipulated in the "Regulations for the Prevention and Control of Coal and Gas Outbursts." This research achieves a transition from empirical estimation to theoretical calculation for rock pillar thickness，providing a quantitative design basis for safe coal uncovering in tunnels under complex geological conditions and offering significant practi⁃ cal guidance.
    Research on the Preferred Mining Methods and Parameter Optimization of Inclined Very Thick Ore Body
    HUI Qinglong SUN Bo
    2025, 41(10):  51-56. 
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    Aiming at the problems of low production capacity and poor operation safety caused by the unreasonable mining methods and quarry structure parameters adopted by some mines ，a typical calcite mine in southern Anhui Province was taken as an example，and based on the synergistic analysis of on-site engineering investigation，theoretical analysis，numerical simulation and other methods，the original min⁃ ing methods and quarry structure parameters adopted by the mines were optimized，and the technical and economic indexes of different mining methods were compared. The three-dimensional numerical model was constructed for the sensitivity analysis of the structural parameters of the mining field，and the following con⁃ clusions were drawn.Compared with the traditional shallow-hole mining method，the medium-deep-hole mining method of small-segmented empty field has significant advantages in terms of the degree of mechani⁃ zation，production capacity，and the safety of mining. Based on the theory of mine perimeter rock classifica⁃ tion and rock mechanics，when the width of mine room is optimized to 10 m and the width of mine pillar is optimized to 8 m，the safety coefficient of mine pillar reaches 2.27，and the overall safety is better. Through the sensitivity analysis of the structural parameters of the quarry，the adoption of Scheme 2 (mine room width of 10 m，mine pillar width of 8 m) is more reasonable in the control of quarry perimeter rock，mining efficiency，etc，which improves the production capacity and ensures the safety of the mining.The research can provide reference for the mining of similar ore bodies.
    Research and Application of Botton-Side Joint Compensation Support Technology for Bottom Drum Control in Soft Rock Roadway
    SUN Lele XIAO Changchun PANG Jianyong HAO Zerui
    2025, 41(10):  57-61. 
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    Under the action of strong disturbance and high stress in the deep part，it is extremely diffi⁃ cult to control the deformation of the roadway floor. To solve the problems of fast deformation speed and large deformation volume of the bottom drum in the deep soft rock roadway，taking the severe bottom drum defor⁃ mation induced by the outer section of the 1137（1）track in Zhangji Mine as the engineering background，a technical solution for the treatment of the reverse bottom arch caused by the anchor injection net spray is pro⁃ posed. A research method combining theoretical analysis，numerical simulation and engineering practice is carried out，a mechanical analysis model of the base plate is constructed，and the failure depth of the base plate is obtained. Research shows that under the effect of strong disturbance，the excessive fragmentation of the surrounding rock of the roadway，the decline in strength，and the continuous expansion and extrusion of the fractured area of the surrounding rock are the main reasons for inducing the bottom drum. A support opti⁃ mization countermeasure for bottom-side joint compensation is proposed，forming a bottom-side combined support bearing structure. The technical solutions of shotcrete sealing，grouting reinforcement，and anchor cable reinforcement at the bottom corners are adopted. Based on the engineering geological conditions，the optimal support parameters for the reverse bottom arch depth of 1.0 m，steel mesh diameter of 12 mm，and a shotcrete strength of C20 are determined through simulation. The combined anchor support and reverse bot⁃ tom arch form a closed support structure，which plays an overall role in stress recovery，surrounding rock re⁃ inforcement，stress transfer and bearing ring control，achieving good application results and providing engi⁃neering reference and guidance for the treatment of bottom drum.
    Research Status and Development Trend of Flotation Technology of Micro-fine Hematite
    DENG Lijia MA Fangyuan
    2025, 41(10):  62-67. 
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    Flotation is the main method to deal with fine hematite，especially the reverse flotation process is widely used in industrial production. The research progress of flotation reagents and enhanced flotation technology for fine hematite in recent years was systematically reviewed.In terms of flotation re⁃ agents，the performance characteristics and mechanism of collectors (cationic / anionic reverse flotation col⁃ lectors，new compound，combination and microbial collectors)，inhibitors (starches，celluloses and their modified products and activators are described in detail. In the aspect of strengthening flotation technolo⁃ gy，the technical advantages and mechanism of nanobubble flotation in improving flotation rate and selec⁃ tivity，ultrasonic flotation in improving mineral surface properties and reagent efficiency，carrier flotation and flocculation flotation in strengthening micro-fine particle recovery were analyzed. This paper points out the shortcomings of the current research in the aspects of reagent cost，environmental friendliness and in⁃ dustrial application of technology，and looks forward to the future development direction of fine hematite flotation technology，which provides reference for the efficient and green development and utilization of he⁃ matite resources in China.
    Study on Titanium Reduction and Upgrading of a Titanium-bearing Iron Concentrate in Chengde
    LI Zhuguo WANG Meng MI Hongcheng LIU Zhe
    2025, 41(10):  68-72，77. 
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    The titanium-bearing iron concentrate in Chengde region has an iron grade of 64.20% and a TiO₂ content of 1.99%. A detailed investigation was conducted on the mineralogical composition of titani⁃ um and the de-titanium process in the concentrate. Phase analysis revealed that titanium mainly exists in the forms of ilmenite，sphene，and rutile，and these minerals are closely associated with magnetite as ag⁃ gregates. When the grinding fineness reaches 90% passing 38 µm，through two-stage low-intensity magnet⁃ ic separation，the TiO ₂ content in the titanium-bearing iron concentrate can be reduced to 0.94%. The yield，recovery and grade of the magnetic concentrate under these conditions are 90.68%，97.96% and 69.30%，respectively. In terms of washing magnetic separation，the effects of different processes-includ⁃ ing single-stage washing magnetic separation，desliming followed by washing magnetic separation，and two-stage washing magnetic separation-on titanium removal were investigated. The results show that after two-stage washing magnetic separation，the TiO₂ content in the concentrate decreases to 0.91%，the iron grade increases to 68.93%，the concentrate yield reaches 81.02%，and the iron recovery is 86.18%. The research results provide a theoretical foundation and experimental basis for the iron enrichment and titani⁃ um reduction processes in titanium-bearing iron concentrate.
    Study on Beneficiation Experiment of a Low-grade Lead-Zinc Ore Based on Orthogonal Test
    HUANG Peng, KANG Jian, YIN Jin WU Mingli GAO Si, LIU Weiyin, LIU Shuang,
    2025, 41(10):  73-77. 
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    The lead grade of a low-grade lead-zinc ore in Hubei is 0.76%，and the zinc grade is 1.37%. The lead element mainly occurs in galena，sulfur antimony lead ore and cerussite，zinc mainly pres⁃ ents in sphalerite. Gangue minerals are mainly dolomite and quartz. The experimental conditions determined by grinding conditional test and orthogonal test were adopted. Under the conditions that the grinding fineness was -0.074 mm accounting for 75%，the lead was separated by one roughing，two cleanings and one scav⁃ enging，and the lead tailings were separated by one roughing，two cleanings and one scavenging zinc selec⁃ tion closed-circuit process test. The lead concentrate with lead grade of 45.72% and recovery rate of 80.25% and the zinc concentrate with zinc grade of 45.44% and recovery rate of 91.02% were obtained. The efficient separation of lead and zinc was realized，and qualified lead concentrate and zinc concentrate products were obtained.
    Comparative Study on the Grinding Performance of Nano-composite Ceramic Balls Versus Steel Balls in Ball Milling
    LI Mannian JU Haoran WANG Feng
    2025, 41(10):  78-82. 
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    Aiming at the problems of serious overgrinding，high energy consumption and limited im⁃ provement of iron concentrate quality in the third stage ball milling system of a concentrator in Inner Mongo⁃ lia，the grinding experiment of nano-composite ceramic balls instead of steel forging was carried out. By sys⁃ tematically comparing the grinding technical efficiency and product particle size composition of ceramic balls and steel balls under different ball loading systems，filling rates，grinding concentrations，and time conditions，it was concluded that the qualified particle size(-0.075+0.018 mm) yields of steel balls and ce⁃ ramic balls were 62.74% and 63.02%，respectively. The grinding technical efficiencies of steel balls and ce⁃ ramic balls were 69.28% and 70.46%，respectively. The qualified particle size yield rate and grinding tech⁃ nical efficiency of ceramic balls were higher than those of steel balls. The comparison of magnetic separation effect of different media grinding products and ball consumption and energy consumption in grinding process shows that the iron grade of ceramic ball magnetic separation concentrate is slightly higher than that of steel ball grinding，and the content of harmful impurities in ceramic ball grinding magnetic separation concen⁃ trate is lower. Under the same conditions，ceramic ball grinding can obtain better quality iron concentrate. The energy consumption and power consumption of ceramic ball grinding are lower than those of steel ball grinding，and the effect of energy saving and consumption reduction is remarkable. Nano-composite ceram⁃ ic balls have good applicability in fine grinding of iron ore，which can provide technical reference for high�efficiency and energy-saving grinding of similar ores.
    Experimental Study on Magnetic-Gravity Separation Process of a Lean Magnetite Ore in Anshan
    ZHANG Xiaoliang CHEN Zhonghang LI Pengcheng YAO Qiang
    2025, 41(10):  83-86，91. 
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    In order to make efficient use of a lean magnetite resource in Anshan area，aiming at the problems of large middle return，low separation efficiency and high operation cost for the original separation process，a magnetic-gravity combined separation process is proposed，which uses one-stage grinding and one-stage magnetic separation，one-stage magnetic separation concentrate via spiral chute gravity separa⁃ tion to obtain qualified concentrate，spiral chute gravity separation tailings secondary classification，two�stage grinding-magnetic separation，two-stage magnetic separation concentrate fine screening and grading， under-size as qualified concentrate，the over-size via magnetic separation column cleaning，first-stage magnetic separation tailings，second-stage magnetic separation tailings，magnetic separation column tail⁃ ings combined into total tailings. The iron grade of the final concentrate was 66.35%，the recovery rate was 79.88%，and the tailings grade was 10.41%. The laboratory test results show that the magnetic-gravity sepa⁃ ration process can obtain some qualified gravity concentrate in advance under the condition of coarse grind⁃ ing，and throw out some qualified tailings，reduce the load of the second stage mill，improve the processing capacity of the beneficiation equipment，simplify the process flow，reduce the cost of beneficiation，and im⁃ prove the economic benefit，which can provide technical reference for the efficient separation of similar lean magnetite.
    Experimental Study on Stage Grinding and Stage Separation Process for a Certain Extremely Poor Hematite Ore
    ZHANG Xingyi LIU Shuang'an YANG Huili XIE Xiaomeng NIU Zhanliang WANG Luxin CHEN Guorong
    2025, 41(10):  87-91. 
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    The iron content of the ore mined from a large iron mine is 19.41%，and the iron-bearing minerals are mainly hematite，limonite and magnetite. Gangue minerals mainly include quartz，ortho⁃ clase，actinolite and so on. On the basis of process mineralogy and property analysis，the separation test was carried out by one stage grinding-low intensity magnetic separation-high intensity magnetic separa⁃ tion，one stage mixed concentrate via two stage grinding- low intensity magnetic separation-high intensity magnetic separation，and second stage mixed concentrate via anionic reverse flotation process. The grind⁃ ing fineness of the first stage is -0.074 mm 60%，the magnetic field intensity of the first stage low intensity magnetic separation is 200 kA/m，the magnetic induction intensity of the first stage high intensity magnetic separation is 0.9 T，the second stage grinding fineness on the first stage magnetic separation mixed concen⁃ trate is -0.074 mm 90.81%，the magnetic field intensity of the second stage low intensity magnetic separa⁃ tion is 184 kA/m，and the magnetic induction intensity of the second stage high intensity magnetic separa⁃ tion is 1.0 T. The two-stage magnetic separation mixed concentrate uses NaOH as the pH regulator，KDF as the inhibitor，CaO as the activator，TDK-II as the collector，through one roughing，one cleaning and three scavenging reverse flotation. The iron grade of the concentrate is 66.45%，the metal recovery rate is 53.92%，and the iron grade of the tailings is 10.62%. The test process is simple and reasonable，which provides a technical basis for the efficient utilization of similar ores.
    Experiment on Influence of Filling Material on Separation Index of a Copper-Sulfur Ore
    WANG Junhao WANG Fei LIN Yuanyuan
    2025, 41(10):  92-95. 
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    Aiming at the problem of the deterioration of flotation index caused by the entraining of un⁃ derground filling materials into the raw ore in a copper-sulfur mine，a systematic experimental study on the influence of filling materials on copper-sulfur separation was carried out. Through the chemical multi-ele⁃ ment analysis of the raw ore and the filling material，it is found that the content of CaO and MgO in the fill⁃ ing material is high，which will significantly increase the pH value of the pulp and deteriorate the flotation environment. The optimum pulp pH value，collector type and dosage，inhibitor type and dosage of flotation were determined by condition test. The closed-circuit test results show that when the filling material is mixed with 5%，the copper recovery rate decreases by 3.477 percentage points，and the copper concentrate grade and sulfur recovery rate also decrease. Filling material has a significant negative impact on copper-sul⁃ fur flotation，and controlling its mixing ratio within 3% can effectively alleviate the fluctuation of indicators. The research results provide a reference for on-site production adjustment.
    Research Progress and Industrial Production Status of Preparation for High-pure Iron Concentrate
    DENG Yufen
    2025, 41(10):  96-99，104. 
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    High-pure iron concentrate requires a total iron content of over 71.50% and impurity con⁃ tent such as SiO₂ below 0.3%. These extremely high-quality standards pose significant technological chal⁃ lenges for industrial production. Based on a comprehensive analysis of preparation technologies for high�pure iron concentrate and literature research，the following conclusions can be drawn.①The process miner⁃ alogical characteristics of iron ore and ordinary iron concentrate are key factors determining the feasibility of producing high-pure iron concentrate. An evaluation system based on mineralogical genetic characteristics can efficiently screen raw materials suitable for producing high-pure iron concentrate.②In terms of prepara⁃ tion technology，if the ore has a relatively coarse dissemination grain size and simple mineral composition and structure，it can be ground until the content of -0.043 mm particles exceeds 95% to achieve sufficient monomer liberation. Then，a stage grinding-single magnetic separation process can be employed to produce high-pure iron concentrate with a total iron content above 71.50%. For magnetite with fine dissemination grain size and complex mineral composition，further flotation or magnetic-flotation combined processes are required to efficiently produce high-pure iron concentrate with a total iron content higher than 71.5% and impurity content such as SiO₂ below 0.3%. When the concentrate contains a high amount of intergrowth parti⁃ cles，chemical leaching methods using sulfuric acid or sodium hydroxide can be applied to further reduce the content of SiO₂ and other impurities. However，due to environmental and cost concerns，leaching is not the preferred option for industrial production.③With technological breakthroughs such as the magnetic sus⁃ pension separation-reverse flotation combined process developed by Baosteel and the short-flow beneficia⁃ tion technology for extremely refractory lean hematite ore introduced by Ansteel，green and low-carbon， short-flow optimized production processes for high-pure iron concentrate are gradually advancing its large�scale industrial development. To further achieve green，efficient，and scalable production of high-pure iron concentrate，future efforts should continue to focus on the research and development of green processes such as high-voltage pulse crushing-selective liberation，photoelectric sorting-biological desilication，and com⁃ prehensive resource utilization.
    Flotation Kinetic Performance Test and Analysis of a Copper Mine Plant in Heilongjiang
    HAN Zhibin HU Senwei ZHANG Fuya
    2025, 41(10):  100-104. 
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    Aiming at the problem that the flotation index of a copper concentrator in Heilongjiang Prov⁃ ince is not ideal，the flotation kinetic performance test and analysis were carried out. The JJF-320 and KYF-320 flotation machines of series I roughing operations were taken as the research objects. The key ki⁃ netic parameters such as air volume，air dispersion，gas holdup，slurry suspension capacity and bubble loading rate were systematically tested. The results show that the air dispersion effect in the flotation ma⁃ chine is good. Compared to the JJF-320，the KYF-320 exhibited a slightly higher aeration rate，which could be moderately reduced based on actual production needs.The gas holdup in the two flotation machines is within a reasonable range and evenly distributed. The ore particles in the two flotation machines are fully suspended. The bubbles in the two flotation machines have strong ore carrying capacity，and there is no obvi⁃ ous desorption phenomenon during the rising process，and the mineralization effect is excellent. The re⁃ search provide a theoretical basis for the optimization of the operation parameters of flotation equipment， which is helpful to improve the separation efficiency and process adaptability.
    Creep Characterization Analysis and Fractional-order Models Construction of Muddy Siltstone under Frozen Condition
    LI Penghui, LIU Xiaoying CHU Jingjing
    2025, 41(10):  105-109，114. 
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    In order to more accurately understand the creep characteristics of mud siltstone in the fro⁃ zen state，and to provide a solid and reliable theoretical basis for the construction of freezing method，the mud siltstone was subjected to three temperatures of unconfined compressive strength test and two loading levels of creep test，through the introduction of fractional order differential theory into the Abel viscous pot，then a fractional order Burgers model was established，which was compared with integer order model. The results show that under the uncon-fined compressive strength test，the peak stress of the rock gradual⁃ ly increases with the decrease of temperature，showing a significant increase in strength，and the speci⁃ mens at low temperature show more obvious brittle characteristics at the time of destruction. Under the creep test，the test curve of muddy siltstone can be divided into two stages of rapid creep and stable creep，the rapid creep stage strain grows rapidly，accounting for about 90% of the total strain，the rapid response of the initial stress makes the strain curve rise steeply at the beginning of the loading，and with the passage of time，the curve gradually becomes flat and enters the stable creep stage，which is almost constant，and the stabilized strain increases with the reduction of freezing temperature or increase of load⁃ ing level. The stable strain increases as the freezing temperature decreases or the loading level increases. By constructing the Abel viscous pot based on the R-L fractional order integral and introducing the Burgers model，the integer-order and fractional-order Burgers models were established to describe different load⁃ ing levels and different freezing temperatures，and the inversion of the model parameters yielded a good⁃ ness-of-fit of the integer-order model of only 0.918，while that of the fractional-order model reached 0.998. The fitting results were as follows，the goodness-of-fit of the integer-order model was only 0.918， and that of the fractional-order model reached 0.998，the fitting results and the test curve almost complete⁃ ly overlap，and the significance of the model parameters is clear，which is convenient for the direct appli⁃ cation in practical engineering. The study provides a theoretical basis for the long-term stability of rock en⁃ gineering.
    Research on Acoustic Emission Characteristics of Main Roof Rock Failure in Coal Seams under Different Loading Modes
    LI Huijie
    2025, 41(10):  110-114. 
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    To investigate the evolution of acoustic emission (AE) parameters and the differences in the fracturing and failure processes of main roof rocks in coal seams under various loading modes，uniaxial com⁃ pression，direct tensile，and indirect tensile tests were conducted on main roof rock samples from the 15# coal seam of the Xinshanghai No.1 Mine，with AE signal characteristics recorded throughout. The results show that the uniaxial compressive strength of the main roof rock is 79.15 MPa，the direct tensile strength is 5.2 MPa，and the indirect tensile strength is 1.3 MPa. In the uniaxial compression test，the AE damage ac⁃ celeration point appears at a stress level of 20%. In the direct tensile test，it occurs at 70% stress level，and in the indirect tensile test，it emerges at 90% stress level. Under different loading modes，micro-crack de⁃ velopment dominates throughout the entire uniaxial compressive failure process，whereas the scale of crack development in tensile tests is larger than that observed in compression tests. In compression tests，rock fail⁃ ure progresses from small cracks to larger fractures under applied stress，with the development of major frac⁃ tures leading to instability and failure. The indirect tensile test is similar to that.
    Research on the Classification Method of Gravel Particle Shapes Based on Principal Component Analysis and K-means Clustering
    ZHANG Zhi WANG Shuai HU Haiwei WANG Xu WU Zhenwei
    2025, 41(10):  115-125. 
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    The morphology of gravel particles is a critical factor influencing the mechanical behavior of conglomerates. The existing shape parameter systems are characterized by an excessive number of indices and overlapping classification criteria，which limit the applicability of classification methods. To address these issues，this study proposes a novel gravel particle shape classification method that integrates multi-pa⁃ rameter dimensionality reduction with machine learning. Initially，three-dimensional reconstruction data of gravel particles are obtained through CT scanning technology，and shape parameters including form，round⁃ ness，and sphericity are calculated using Python programming. Subsequently，Pearson correlation coeffi⁃ cient heatmaps are employed to quantify parameter correlations，and representative shape parameters are se⁃ lected through hierarchical clustering combined with principal component analysis. Finally，the K-Means clustering method is implemented，the optimal number of clusters is determined by the elbow method and silhouette coefficient，resulting in the classification of gravel particle shapes into three or four categories， and the classification method is simplified. The proposed classification method provides valuable insights for analyzing the mechanical properties of conglomerates and optimizing resource development efficiency. Keywords gravel particle morphology，principal component analysis，K-Means clustering，machine learning，classification methods
    Comprehensive Evaluation of Rock Mass Quality and Research on Rock Mechanics Properties of the Huaaobaote Silver-Lead Metal Mining
    GUO Xudong WANG Haichao LI Haidong ZHANG Yu LUO Yifan
    2025, 41(10):  126-131. 
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    In order to ensure safe production in mines，accurate rock mass quality assessment and the revelation of basic mechanical properties of rocks are of great significance. This study focuses on the rock mass of the 500 m，660 m，and 855 m level roadways in the Huaaobaote Silver-Lead metal mining in Inner Mongolia. Uniaxial compression，splitting，and shear rock mechanics tests were conducted to obtain rele⁃ vant rock mechanics parameters. Additionally，investigations and analyses of joints and fissures were car⁃ ried out in different mining areas of the middle section of the 500 m level. Based on these results，a compre⁃ hensive assessment of rock mass quality was conducted by combining the RMR method with the Q-system evaluation results.The results indicate that the compressive strengths of the rocks at the 500 m，660 m，and 855 m levels are 63.22 MPa，33.69 MPa，and 59.56 MPa，respectively. The elastic moduli are 30.10 GPa， 21.89 GPa，and 36.68 GPa，respectively. The tensile strengths are 7.23 MPa，3.85 MPa，and 4.66 MPa，re⁃ spectively，while the cohesion values are 11.72 MPa，9.49 MPa，and 15.70 MPa，respectively. The rock mass at the 500m level generally exhibits well-developed structural plane fractures，slight weathering，and joint surfaces ranging from smooth to moderately rough.The RMR scores for the I，II，and III stope areas at the 500m level are 52，52，and 59，respectively，while the corresponding Q system scores are 6.7，7.3， and 4.1. Based on the comprehensive rock mass quality evaluation，the rock mass at the 500 m level is clas⁃ sified as average quality (Class II to III).The findings of this study provide a reference for rock mechanics and rock mass quality evaluation in silver-lead metal mining areas.
    Analysis on the Basic Characteristics and Evolution of Geological Structures in Coal Mining Area of Western Fujian
    QIU Zhanlin, GUO Xin ZENG Dongfu WANG Zhandang QIN Qiong LAI Jingxiang ZENG Guiling, SONG Bailin
    2025, 41(10):  132-138. 
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    In order to clarify the basic situation of geological structures in coal mining area of western Fujian，by analyzing the regional tectonic background where it is located and combining the engineering da⁃ ta exposed in production practice，the basic characteristics of geological structures such as folds，(gentle) faults and quasi-contemporaneous structures in coal mining area of western Fujian，were statistically ana⁃ lyzed and preliminarily summarized by using the tectonic analysis method. On this basis，the tectonic stress field and evolution model of the area were preliminarily studied. The results show that the superposition of the near EW trending structures and the early EW trending structural reconstruction make the regional struc⁃ tures more complicated. The typical structures in the area generally belong to the superposition type of down⁃ ward sliding and upward pushing，upward sliding and downward pushing，or both sliding and pushing. The fold structures are mainly oriented in the near NE and NWW directions，which are basically consistent with the distribution direction of the main regional geological structures. The fault structures are mainly strike�slip faults and high-angle faults，which are basically consistent with the main stress directions of the region⁃ al tectonic stress field，they have undergone multiple major tectonic changes such as the late Indosinian pe⁃riod，early to late Yanshan period，and late Himalayan period，and correspond to the formation and evolu⁃ tion of the sliding cover structure，thrust nappe or thrust-slip type boundary faults，and coal-controlling structures. Moreover，the magmatic activity of the Yanshan period played a decisive role in the formation of the overall structural profile such as the thrust nappe structure. This study can provide some theoretical refer⁃ ence for searching hidden coal resources and safety management of coal mine roof or other aspects in areas with similar structural characteristics in the future.
    Technology Improvement Practice of Axial Flow Fan in Metal Mine
    WANG Yongqun WU Lengjun ZHANG Mingfeng
    2025, 41(10):  139-142. 
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    The on-site operation environment of axial flow fan in metal mine is complex. The environ⁃ ment of high humidity，high dust and high air temperature in underground mine is superimposed on the oil fume exhaust generated by the operation of trackless equipment. During the high-speed and long-term oper⁃ ation of fan impeller，it is easy to cause the corrosion of impeller blades，which leads to the attenuation of fan performance and the shortening of service life，which affects the safety and efficiency of underground ventila⁃ tion in mine. In order to solve the above problems，the targeted transformation of this type of fan is carried out，and three core technical structure improvement schemes are put forward. First，the new steel-alumi⁃ num composite blade is adopted to realize the adjustable blade angle while prolonging the service life of the blade and optimize the operation performance of the fan. The second is to add an electric brake device at the end of the motor，which effectively solves the technical problem that the mine axial flow fan needs to stop in a short time. The third is to configure the impeller disassembly device to realize the safe and fast installation and maintenance of the fan impeller and blades. The practice shows that the three improvement schemes can effectively solve the problems of blade corrosion，low shutdown efficiency and inconvenient operation and maintenance in the actual operation of the fan. It is of great significance to ensure the stable operation of the fan，prolong the service cycle of the equipment and improve the operation and maintenance efficiency of the mine underground ventilation system. It can provide reference for the optimization and upgrading of ventila⁃ tors in similar metal mines.
    Research and Application on Oil Leakage Monitoring of Hydraulic Station of Coal Mine Hoist Based on Video AI
    ZHANG Chen ZHANG Hongkai YANG Liezhen WU Jianguo ZHU Zejian CAO Xu
    2025, 41(10):  143-147. 
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    During the long-term operation of the hydraulic station of coal mine hoist，oil leakage of⁃ ten occurs due to aging of seals and pipeline damage，which not only wastes resources but also has poten⁃ tial safety hazards. The traditional manual inspection method has low efficiency and high missed detection rate. Based on the YOLO target detection model，this paper designs an oil leakage monitoring system based on video AI. The system first collects the image data of the hydraulic station under normal and oil leakage conditions. Then，the image data set is constructed by data preprocessing method，and the anomaly detec⁃ tion and recognition model is constructed by extracting the preprocessed image features and machine learn⁃ ing model. Finally，according to the actual environment of the hydraulic station，the risk warning and re⁃ sponse of the abnormal state are realized. In practical application，the accuracy of oil leakage detection is 92.1 % ，and the average response time is 0.2 s. It shows good robustness and real-time performance， which is significantly better than the traditional detection method. The system can significantly improve the detection efficiency and accuracy in the complex practical application environment of coal mines，effective⁃ ly reduce the potential safety hazards caused by missed detection，ensure the normal operation of hydraulic stations，and reduce the dependence on manual inspection，save human resources and reduce economic losses.
    Study of Preparation of Stone-Imitation Ceramic Tiles by Low-temperature Firing of Fine Mud from Typical Tailings in Chengde and Their Properties
    BAI Yaning DUAN Yupeng CHAI Zongce ZHENG Yongchao HUANG Zhaohui FANG Minghao MIN Xin
    2025, 41(10):  148-157，162. 
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    In order to promote the high-value utilization of tailings resources and develop low-cost and environmentally friendly stone-like building materials，the typical vanadium-titanium magnetite tail⁃ ings，molybdenum tailings and fluorite tailings in Chengde area were used as the main raw materials，sup⁃ plemented by waste glass powder，Na2CO3，K2CO3 and other additives. The effects of particle gradation and waste glass powder content on the structure and properties of stone-like ceramic materials sintered at low temperature (850 °C ) were systematically studied. The results show that when the mass ratio of large perti⁃ cles(3~2 mm)，middle particles(2~1 mm)，small particles(1~0.075 mm) and fine mud(-0.075 mm) in vanadi⁃ um-titanium magnetite tailings is 25∶10∶5∶20，the internal particles of the sample are tightly packed and the compactness is the best. When the content of waste glass powder is 10%，the bulk density of the sample is 2.24 g/cm3 ，the apparent porosity is 18.21%，the water absorption is 8.14%，and the flexural strength and compressive strength are 13.29 MPa and 29.80 MPa，respectively. The addition of waste glass powder can form more glass phase during the sintering process，effectively promote mass transfer and pore filling，and sig⁃ nificantly improve material properties. The research results provide a feasible process path and theoretical ba⁃ sis for the large-scale application of tailings resources in Chengde area in imitation stone ceramic materials.
    Experimental Study on Segmented Neutralization Treatment of Acid Mine Drainage with High Concentration of Manganese
    XU Weijuan, CHEN Jun, ZHANG Jing, WEN Wen, LU Yong,
    2025, 41(10):  158-162. 
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    In order to improve the utilization rate of slaked lime in neutralization treatment of acid mine wastewater，reduce reagent consumption and reduce operating costs，aiming at the problems of large dosage and large sludge production in the treatment process of a high manganese acid mine wastewater in Maanshan City，based on the traditional neutralization treatment method，the experimental study of grading neutraliza⁃ tion treatment was carried out，and the target pH control value of grading neutralization treatment was deter⁃ mined. The results show that when the pH value of the first stage neutralization control wastewater is 5~6， and the pH value of the second stage neutralization control wastewater is 9.8，the total amount of hydrated lime added in the grading neutralization treatment is 2.23 g/L. The amount of hydrated lime was reduced by more than 40% compared with the traditional neutralization method. The amount of sludge produced by the grading neutralization treatment is 3.37 g/L，which can be reduced by more than 65% compared with the tra⁃ ditional neutralization method. The manganese content of the sludge produced during the secondary neutral⁃ ization treatment was 38.66%. The use of graded neutralization treatment can effectively reduce the amount of lime dosage and reduce the amount of sludge.
    Study on Removal of Lead Ions in Wastewater by Mechanical Activated Talc
    ZHAO Xiaokang XIE Suhan LI Zhao CHEN Min HUANG Junwei DAI Shujuan LI Pengcheng
    2025, 41(10):  163-169. 
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    To efficiently remove heavy metal lead ions from aqueous solutions，mechanical activa⁃ tion was applied to the natural clay mineral talc. The effect of activated talc on precipitating lead ions was explored，and the mechanism was analyzed. The study shows that mechanical activation induces lattice distortion in talc，reducing its crystallinity until complete amorphization. Active hydroxyl groups on the talc surface are exposed and dissolved，reacting with carbon dioxide in the atmosphere to form basic lead carbonate precipitation with lead ions. Compared with natural talc with lower reactivity，mechanical activa⁃ tion significantly enhances the physical and chemical properties of the mineral. When the ball mill speed is 400 r/min and the talc dosage is 0.4 g/L，the treatment capacity of mechanically activated talc for lead ions in a 500 mg/L lead nitrate solution reaches more than 1 069 mg/g. The research results provide a new approach for the resource utilization of clay minerals，and have the dual benefits of environmental remedia⁃ tion and solid waste utilization，which is of great significance for promoting the green and sustainable de⁃ velopment of heavy metal wastewater treatment.
    Evaluation of the Neutralization Efficiency of Lime Slurry on Effluent from Fenton Oxidation Reactors
    ZHANG Zhipeng QIN Yang FANG Lin SHI Junqing PENG Jie ZHOU Qiqi WEI Kegang
    2025, 41(10):  170-175，186. 
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    In the industrial water treatment section of a copper mine，wastewater is first treated via Fenton oxidation，followed by neutralization with lime slurry to bring the treated effluent to near-neutral pH. Subsequently，polyacrylamide（PAM）is added to flocculate fine particles of undissolved lime in the bottom sludge. The resulting supernatant is discharged in compliance with regulatory standards，while the bottom sludge is transported to the tailings pond. In this process，the lime slurry used has a concentration of 10%. Given that the solubility of Ca（OH）₂ in water at 20 °C is only 0.165 g/100 g H₂O，it is inferred that the neu⁃ tralization reaction efficiency of the lime slurry in field applications is low.To verify this inference，compara⁃ tive neutralization experiments were conducted using two alkaline agents of 40% NaOH solution and the on�site lime slurry to treat the acidic effluent after Fenton oxidation. In addition，instrumental analyses，includ⁃ ing particle size analysis，scanning electron microscopy（SEM），and energy-dispersive X-ray spectroscopy （EDS），were employed to investigate the lime content in the underflow slurry from the lime neutralization tank，providing cross-validation for the experimental results.The results indicate that the neutralization reac⁃ tion efficiency of the 10% lime slurry used on-site ranges between 40% and 60%. As the pH of the solution increases，the neutralization efficiency of the lime slurry decreases significantly. Unreacted Ca（OH）₂ co�precipitates with neutralization products such as CaSO₄，forming sludge. This not only results in substantial waste of lime slurry but also causes severe blockage of conveying pipelines.Therefore，to improve efficiency and reduce scaling，it is recommended to first adjust the Fenton-treated tailwater to a pH of approximately 4 using an appropriate amount of lime slurry，followed by the addition of a small quantity of liquid alkali to fur⁃ ther raise the pH to the target range of 6~9. This approach would significantly enhance the reaction efficien⁃ cy of the lime slurry and markedly reduce scaling issues in the system.
    Research and Application of Slope Monitoring and Early Warning System for Open-pit Mines of Benxi Steel Mining
    FU Jianhua LYU Ben HUANG Chong JIANG Xuetao JIANG Fengzi
    2025, 41(10):  176-181. 
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    In order to reduce the risk of slope failures in mines by collecting and analyzing existing geological data from the Nanfen open-pit iron mine，integrating the mine's excavation planning maps with on-site geological surveys，the safety monitoring levels for the pit slopes were classified based on parame⁃ ters such as slope height，gradient，geological conditions，and stability assessments. A comprehensive de⁃ sign was developed for the slope monitoring and early warning system. The implementation of supplementa⁃ ry monitoring technologiesincluding ground-based radar，GNSS，blast vibration monitoring，and internal displacement monitoring were carried out. Through data compilation and analysis，the system provides a reliable basis for evaluating the stability and safety of mine slopes，which achieves full coverage monitor⁃ ing of high and steep slopes exceeding 150 m in height，meets national monitoring standards facilitates a transformation from post-accident response to proactive，pre-accident early warning and prevention. Com⁃ pared to the period before the enhanced monitoring system implemented，equipment loss due to slope in⁃ stability is reduced by approximately 3.7 million yuan/a，effectively preventing personnel injuries. The sys⁃ tem also reduces the risks associated with manual monitoring and significantly decreases the frequency of manual inspections on high and steep slopes，saving about 200 000 yuan/a in labor costs. By predicting and assessing slope risks，the production scheduling systemadjusts and optimizesthe mining sequence ra⁃ tionally. As a result，the optimized ore output increased to 14.59 million t，representing a year-on-year increase of 420 000 t in total ore production，generating additional economic benefits of 49.4466 million yuan/a.
    Application of Concrete-filled Steel Tube Support Technology in Deep High Stress Roadway
    CHEN Jie
    2025, 41(10):  182-186. 
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    To address the difficulty in supporting deep and high-stress roadways，traditional support methods have become inadequate to meet the on-site demands of coal mines The failure phenomena of a cer⁃ tain roadway under the original support conditions were analyzed in detail. It was summarized that deep high-stress roadways have failure characteristics such as large deformation amount and high initial deforma⁃ tion rate，and the support ideas under the existing support technology conditions were sorted out. In view of the insufficient strength of the original support，an innovative proposal was made to use concrete-filled steel tube supports for optimized support. Based on the actual cross-section of the roadway，a support method of straight wall semi-circular arch and reverse bottom arch support was designed，giving full play to the advan⁃ tages of concrete-filled steel tube supports such as high bearing capacity and good adaptability and load cal⁃ culation for the optimized support method was carried out. The results show that the bearing capacity provid⁃ ed by this support method is greater than that required by the roadway，which can effectively meet the sup⁃ port requirements of deep high-stress roadways and is of great significance for improving the stability and safety of the roadway. At the same time，it also provides support design and construction for similar projects. It provides useful references.
    Research on Ice Block Assisted Cooling Technology in Tunneling Faces
    XIE Bo WANG Xiaodong
    2025, 41(10):  187-190. 
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    Ice blocks are often used as an auxiliary cooling method due to their advantages such as economy and easy accessibility. To improve the effect of thermal hazard control in the high-temperature tun⁃ neling face of the mine and reduce the cost of thermal hazard control，taking a certain section of the high�temperature tunneling face as the object，ice block assisted cooling was carried out on the basis of ventila⁃ tion and cooling. The effect of ice block assisted cooling was analyzed and the design parameters were deter⁃ mined. The research is based on the theory of solidification and melting，combined with the SST k-w turbu⁃ lence model，and uses fluent software to simulate the variation law of the temperature field in the high-tem⁃ perature tunneling face under ventilation and ice block cooling. By controlling the number and arrangement of ice blocks，and comparing and analyzing the changes in the temperature field of the tunneling face under different working conditions，the ice block cooling scheme with the best cooling effect is obtained. Tests have proved that compared with the separate ventilation scheme，the temperature within a 3 m range of ice blocks drops significantly，by 7~8℃ compared with when no ice blocks are arranged. When 1 m³ ice blocks were arranged on each side，the minimum temperature within 5 m of the working surface was 23.6 ℃，which decreased by about 10 ℃ compared with when no ice blocks were arranged. When the ice block volume is se⁃ lected at the same 1 m³ and the distance from the tunneling face is 10 m，the temperature distribution is uni⁃ form，mostly between 24 and 25 ℃，and the cooling effect is better. Under the condition of the same amount of ice cubes，after 1 h，the change in air temperature in the roadway has no significant relationship with the shape and arrangement of ice blocks.
    Research and Application of Optimization of Complex Mine Ventilation System Based on Ventsim
    ZHAO Yongjian HAN Kunming JIN Aibing
    2025, 41(10):  191-195. 
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    With the continuous mining of underground metal mines，the network of tunnel engineer⁃ ing is becoming increasingly complex，and ventilation problems are becoming more prominent. An under⁃ ground metal mine in Anhui Province adopts the sublevel open stoping and subsequent filling mining meth⁃ od，which has the characteristics of multi-level mining. Based on the Ventsim，a numerical model of mine ventilation is established. Combined with field investigation and model analysis，the ventilation resistance in the upper mining area of -190 m is large and the inlet air is polluted. The air leakage in the -240 m middle mining area leads to insufficient air volume in the western mining area. The return air in the west⁃ ern mining area of the - 290 m section is not smooth. In view of the above problems，an optimization scheme of zoning regulation and air leakage control is proposed. Installing auxiliary fans are installed in the upper mining area of - 190 m to reduce ventilation resistance. Plugging the air leakage channel is plugged in the middle section of -240 m and -290 m，and the auxiliary fan is installed in the -290 m to assist the return air.Verified by the ventilation network solution，the optimized air volume of each section is balanced，and the wind speed meets the safety regulations，which effectively solves the problem of air flow regulation.This study can provide reference for the optimization and control of ventilation system in the same type of mine.
    Research and Application of Intelligent Sprinkling System in Open-pit Metal Mines
    LUAN Fujia WANG Kaixiang
    2025, 41(10):  196-200，207. 
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    Against the backdrop of digital mine construction，the traditional open-pit mine road sprin⁃ kling mode has shortcomings such as low operation efficiency and severe water resource waste，and is diffi⁃ cult to meet the needs of efficient operation and maintenance as well as green development of modern mines. However，automatic control technology evolves toward intelligence，networking，and centralized manage⁃ ment and control，providing key support for the upgrading of sprinkling operations. Based on this technolo⁃ gy，an intelligent sprinkling algorithm suitable for open-pit mine roads is proposed，and an integrated sys⁃ tem of "monitoring stations-management platform- on-board terminals-APP" is constructed.Environmental monitoring stations are deployed along mine roads to collect real-time road condition and environmental in⁃ formation，which is then aggregated to the central control platform. Through the algorithm，accurate calcula⁃ tion of sprinkling points and optimal route planning are completed，realizing the linkage between fixed sprin⁃ kling and mobile sprinkling，intelligent day-and-night scheduling，dynamic optimization of sprinkler truck routes，and automatic control of the fixed sprinkling system.Verified by actual mine engineering，the system has feasible functions and can effectively improve the efficiency of sprinkling operations and the utilization rate of water resources，which provides practical reference for the intelligent upgrading of road operation and maintenance and efficient resource utilization in similar open-pit mines.
    Application of Geophysical Prospecting in the Survey of Hidden Disaster-causing Factors of a Complex Old Goaf
    JIANG Feng GUO Wei,
    2025, 41(10):  201-207. 
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    For complex，historically incompletely backfilled old mines where personnel access to working faces for 3D laser scanning，geological exploration，or drilling operations is restricted due to safety concerns，accurately determining the volume of goafs becomes challenging. To investigate the oc⁃ currence status and distribution of these goafs，a combined geophysical method utilizing ground-based microtremor surveying and induced polarization sounding was employed to delineate the spatial distribu⁃ tion of goafs both horizontally and vertically. Results indicate that by implementing high-density（20 m spacing between measurement points）microtremor surveying integrated with IP sounding，the estimated volume of goafs reached approximately 1.36 million m³，showing only a 5.6% deviation from the statisti⁃ cally documented volume of 1.44 million m³. The integration of microtremor surveying and induced polar⁃ ization sounding effectively identified the geometry and distribution of the voids，yielding reliable and credible results. By summarizing the application of geophysical prospecting techniques in detecting old goafs at a specific mine，this study demonstrates that the combined method of high-density surface micro⁃ tremor surveying and induced polarization sounding provides a solid technical foundation and support for identifying hidden disaster-causing factors of goafs. It enables the accurate characterization of the three�dimensional configuration of old goafs and proves to be a practical and feasible approach for void detec⁃ tion.
    Study on the Application Efficacy and Mechanism of Tower Mill in the Secondary Stage Grinding of an Iron Mine
    WU Fan MA Ming FANG Xin
    2025, 41(10):  208-211，216. 
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    With the increasing depletion of rich ore resources，the efficient development of refractory fine-grained disseminated iron ore has become the key to the sustainable development of mining industry. Traditional ball mills have problems such as high energy consumption，uneven particle size distribution， and serious over-grinding in the fine grinding process. The application efficiency and energy saving mecha⁃ nism of tower mill in fine grinding of iron ore were systematically studied based on the technical transforma⁃ tion of secondary grinding in an iron mine in Anhui Province. By comparing and analyzing the grinding effect of the tower mill and the ball mill，it is found that the tower mill is significantly better than the ball mill in terms of energy consumption，medium consumption，unit volume efficiency and separation index. The indus⁃ trial test shows that after the original ball mill was replaced by tower mill，the power consumption per ton of ore decreased from 7.57 kW·h/t to 4.30 kW·h/t，the medium consumption decreased from 0.55 kg/t to 0.20 kg/t，the unit volume efficiency increased from 0.43 t/(m³·h) to 1.02 t/(m³·h)，and the iron recovery rate of concentrate increased significantly from 75.49% to 80.35%. The research shows that the advantage of tower mill technology is not only the direct energy saving and consumption reduction，but also the great value add⁃ ed brought by the systematic improvement of the subsequent separation index by improving the particle size characteristics of the product and optimizing the degree of mineral dissociation.
    Research on Large Amount of Fly Ash in Coal Mine Filling
    ZHU Kai XU Bo ZHAO Jixu WANG Yichen, DENG Xiaoxuan,
    2025, 41(10):  212-216. 
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    In recent years，surface subsidence and ecological environment problems caused by coal mining have become increasingly prominent，and coal mine filling mining technology has become an impor⁃ tant way to achieve safe and green mining. The traditional filling materials have the problems of poor con⁃ solidation performance and high cost，and the large amount of fly ash as filling aggregate can not only im⁃ prove the phenomenon of slurry segregation and bleeding，but also realize the utilization of solid waste re⁃ sources. Based on the practice of a coal mine filling project，the workability，mechanical properties and en⁃ vironmental safety of high - volume fly ash filling materials were systematically studied. The results show that whether high-volume fly ash is used as filling aggregate or fly ash + coal gangue is used as filling ag⁃ gregate，the workability of slurry，the strength of sample and the leaching concentration of characteristic heavy metals all meet the requirements of mine filling，and the strength of sample continues to increase in the later stage. The large amount of fly ash as filling material has good engineering application prospects.
    Development and Application of Digital Twin Monitoring System for Ball Mill
    ZHANG Zhengfei WANG Xuefeng YU Jinfa HUANG Jinwu WANG BinjieSONG Tao LIU Daoxi
    2025, 41(10):  217-222，227. 
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    The ore properties of Dashan Concentrator of Dexing Copper Mine fluctuate frequently，and manual operation cannot effectively identify the changes of working conditions，resulting in large fluctua⁃ tions in the grinding process and difficult production control. Aiming at the problems that the key parameters in the field grinding process are difficult to measure directly and the traditional simulation system lacks dy⁃ namic real-time data support，a set of digital twin monitoring system for ball mill is developed through mod⁃ eling simulation and digital twin technology. The system can carry out research and analysis on the mecha⁃ nism model of ball mill motion trajectory and carry out dynamic trajectory research. Combined with the actu⁃ al production of grinding process，the self-organizing mapping neural network (SOM) classification method of mixed filling rate inside the cylinder is selected to realize the dynamic parameter classification and recog⁃ nition of mixed filling rate，so as to realize the dynamic calculation of steel ball motion trajectory. Finally， the digital twin monitoring system of ball mill is designed and developed to realize the three-dimensional model modeling and driving of ball mill，process flow simulation and process data monitoring. The industrial application results show that the system can effectively identify the state of mixed filling rate，improve the prediction accuracy of particle size of grinding products，and provide reliable technical support for the intel⁃ ligent operation and optimal control of ball mill.
    Development and Application of New Odorless and Environment Friendly Flotation Reagents
    WANG Yujie
    2025, 41(10):  223-227. 
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    With the rapid development of urban construction in Nanjing，Meishan mining industry has gradually been surrounded by new residential areas，and environmental problems have become increasingly prominent. Although the long-term use of xanthate in mines has the advantages of low cost and stable indica⁃ tors，the odor of xanthate is particularly obvious in summer，which has become a key factor restricting local green development. Therefore，based on the investigation of the source of odor，Meishan Mining has devel⁃ oped a new environment friendly flotation reagent with low volatility and low toxicity by means of mineral tar⁃ geted identification，quantum chemical calculation and surface spectroscopy analysis. The results show that while maintaining the original flotation index，the VOCs emission of the new reagent is significantly lower than that of the traditional xanthate，and the sulfur recovery rate of the flotation concentrate is significantly improved. Further industrial tests show that the new reagent has stable desulfurization performance and sig⁃ nificantly improves the surrounding air quality. The environmental monitoring cloud platform introduced by Meishan Mining can identify pollution trends, predict the diffusion path of pollution sources, realize dynamic assessment and over-standard warning of air quality and other indicators, and provide forward-looking deci⁃ sion support for pollution prevention and control. The research results provide a feasible path for the green substitution of traditional sulfide ore flotation reagents，which is of great significance to realize the clean pro⁃ duction and regional sustainable development of mining enterprises.
    The Production Transformation Practice for Improving the Beneficiation Technical Indicators of a Refractory Gold Mine
    LIU Jiang HU Xiuming WANG Bin
    2025, 41(10):  228-232. 
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    A refractory gold ore in Fengcheng area of Dandong has high carbon，high sulfur and easy slime，which leads to low recovery rate. Through systematic analysis of ore properties，the technical transfor⁃ mation practice was carried out focusing on grinding classification，flotation process and reagent system. The results show that by optimizing the structural parameters of the hydrocyclone and adjusting the ball filling rate and ratio of the ball mill，the processing capacity and product fineness of the primary mill are signifi⁃ cantly improved. The introduction of preferential carbon removal process and“butyl xanthate + SK-9011” combined collector，and the implementation of the regrinding and reconcentration process of the middle ore effectively improved the monomer dissociation degree and flotation selectivity of gold. After the transforma⁃ tion，the gold recovery rate increased from 82.47% to 88.15%，and the high-efficiency separation and tech⁃ nical indicators of refractory gold ore were significantly improved.
    Research on Preparation and Filling Performance of New Iron Tailings-based Gelling Materials
    WANG Dongxu CHEN Hongbin LI Wanxing CUI Zhiijan
    2025, 41(10):  233-236. 
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    Iron tailings are rich in SiO2 and Al2O3，and have potential pozzolanic activity，but the ac⁃ tivity is low at room temperature，and its reactivity can be improved by mechanical activation or chemical ex⁃ citation. A new type of iron tailings-based gelling material was prepared by using iron tailings，cement clin⁃ ker，gypsum and slag powder as test materials. Through the orthogonal test to optimize the ratio，the optimal combination was determined to be 15% iron tailings，35% cement clinker，10% gypsum，slag powder is the residual (40%)，and water-binder ratio of 0.50. The verification test showed that the compressive strength of the specimens at 3，7，and 28 d was 3.12，7.70 and 13.94 MPa，respectively. Further freeze-thaw cycle and hydration durability tests were carried out. The results show that the cementitious material has good frost re⁃ sistance under standard curing conditions，but the strength loss is significant in low temperature environ⁃ ment. Under the condition of long-term water immersion，the strength of the test block is slightly improved， and the saturated water absorption rate is between 2.17% and 3.11%，showing good hydration stability. The research results provide technical support for the resource utilization of iron tailings and the development of green filling materials.
    Optimization and Application of Low Disturbance Blasting of Two-step Stope in 90 m High Section
    ZHANG Qiang XIE Bingxiang XI Tingtang ZHOU Lin LIU Zhewei ZHANG Deming
    2025, 41(10):  237-242. 
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    In order to reduce the disturbance effect of blasting action on adjacent filling body in the process of two-step mining and improve the stability and safety of filling body in the process of mining opera⁃ tion，the 90 m high section stope of Zhangzhuang Iron Mine is taken as the research object，and the research is carried out by combining LS-DYNA numerical simulation with field industrial test. A three-dimensional model containing explosives，ore bodies and filling bodies is constructed. The fluid-solid coupling algorithm is used to set the thickness of five kinds of wall protection mines of 2.0，2.3，2.5，2.8 and 3.0 m，and the in⁃ fluence range of blasting stress wave and the variation law of stress and displacement of filling bodies are an⁃ alyzed. Taking 406 stope as the object，the simulation results are verified by goaf scanning. The numerical simulation shows that with the increase of the thickness of the wall protection ore，the maximum influence range of the stress wave decreases from 2.74 m to 1.63 m，the peak value of the effective stress decreases from 2.125 MPa to 1.817 MPa，and the peak value of the effective displacement decreases from 0.414 mm to 0.149 mm. When the thickness is greater than 2.5 m，the filling body is only damaged by small damage. The industrial test shows that the filling body under the 2.0~2.5 m wall protection ore is obviously damaged，and there is basically no change at 3.0 m，which is consistent with the simulation results. It is clear that the opti⁃ mal thickness of wall protection ore in the 90 m high section in Zhangzhuang Iron Mine should not be less than 2.5 m，which provides a scientific basis for the optimization of mine blasting parameters and safe min⁃ ing.