Metal Mine

Development and Prospect of Non-blasting Mechanized Mining and Heading Technology in Hard Rock

WANG Shaofeng, SHI Xinlei, ZHOU Zilong

2024, 53(5): 1.

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In recent years,with the continuous expansion of underground engineering construction and resource extraction, hard rock mining and heading technology and equipment have been constantly innovated and developed. Due to the high risk and large induced-damage,the development needs of modern rock engineering are difficult to be met by the traditional drilling and blasting method. With the advantages of safety, efficiency,economy,and rapid intelligent upgrading,the non-blasting mechanized mining and heading technology in hard rock has become the leading development direction in modern rock breaking engineering. In this paper,the status of the development of non-explosive mechanized mining technology in hard rock has been reviewed from three perspectives:rock cuttability,mechanical cutters (rock breaking tools) and mechanical equipment. The development of rock cutability has shifted from single-indicator evaluation to multi-indicator integrated evaluation. The types of mechanical cutters have become more diverse,and their performance has improved with advancements in alloying and coating technologies. The design and manufacturing of these cutters now focus on finding the optimal balance between tool hardness,wear resistance,corrosion resistance,and impact toughness,so as to enhance their lifespan. In addition,rock-breaking machinery and equipment are gradually undergoing a transformation towards larger-scale,heavier-duty,smarter,diversified,and more refined systems. This development aims to achieve efficient,safe,economical,and precise excavation of hard rock. Based on the aforementioned analysis,the future development direction of hard rock non-blasting mechanized mining technology was summarized. However,it is important to consider the challenges that need to be overcome. These challenges include:① Establishing deep rock fragmentation mechanics and energy models to explore methods for utilizing high-stress-induced breakage and controlling high-energy storage in deep hard rock,and developing synergistic rock-breaking methods and technologies through induced-modifications for risk reduction and cuttability improvement;② By elucidating the multi-field and multi-phase coupling of the hard rock breaking process,along with the multi-scale fracture,failure,and fragmentation processes,the multisource combined rock-breaking technologies and equipment,including mechanical,hydraulic,thermal approaches,should be developed;③ By investigating and revealing the mechanical and energetic mechanisms of dynamic disaster of rock with highenergy storage induced by rock-breaking disturbances, the specific prevention and control methods should be proposed; ④ Developing refine and intelligent rock-breaking technology and equipment that are precisely tailored to the rock characteristics, stress conditions,and rock-breaking requirements to establish the systems of non-blasting mechanized intelligent mining and heading methods and technologies;⑤ Constructing a comprehensive process management model for non-blasting mechanized mining,and enhancing the operational workflow of non-explosive mechanized mining in hard rock. Through the aforementioned study efforts,it is anticipated that the widespread implementation of non-blasting mechanized mining will be facilitated, thereby enabling safe,efficient,green,and intelligent excavation in hard rock.

Development and Prospects of Comminution Energy Consumption Theory

ZUO Weiran, DAI Yuansong, XU Jingwei, ANG Yun

2024, 53(5): 16.

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Comminution operations electricity consumption in mine account for nearly 2% of the global total electricity consumption,and are also the most energy-consumptive operating unit in mining production. The energy consumption prediction of comminution process is an essential part of carbon emissions and energy management,mine-site production management,and digital mine construction. This paper reviews the three classic theories on comminution energy consumption by Kick,Rittinger, and Bond,with a focus on introducing the development process of Bond′s theory and discussing its limitations in modern comminution process production practice. Various emerging theories of comminution energy consumption that have been proposed since the 1970s are introduced. The predictive accuracy of the Bond theory model and the emerging theory models for comminution process unit energy consumption are discussed and compared. The application value of energy-based comminution models are summarized in four aspects:comminution process design and equipment selection,comminution process operation efficiency evaluation and optimization,metal mine production capacity prediction and management,and metal mine comminution energy consumption carbon evaluation model. Although the lack of independent intellectual property rights in this field poses obstacles to data security and mining production of China,with the rapid development of digital and intelligent construction in domestic mines,the energy-based comminution models in China is bound to experience significant breakthroughs in a relatively short period of time.

Research Progress on the Metallogenic Characteristics of Sedimentary Lithium Deposits and the Occurrence State of Lithium

CHENG Hongfei, ZHOU Xuanping

2024, 53(5): 28.

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With the rapid development of new energy vehicles and lithium batteries,lithium resources have become important strategic resource for many countries. However,the distribution of global lithium resources is uneven,and China′s lithium resource dependence on foreign countries is as high as 75%. There are abundant sedimentary lithium deposits to be developed, the mineralization characteristics and occurrence state of lithium restricts its separation,extraction and efficient development and utilization. This paper introduces the main types of global lithium resources and their characteristics,analyzes the temporal and spatial distribution characteristics and the formation of geological background of sedimentary lithium deposits,and argues that sedimentary lithium deposits have become an important type of new lithium resources in the world. Due to it has the advantages of large reserves,wide distribution and low exploitation cost,it shows great development value and broad utilization prospect. By summarizing and reviewing the research results of sedimentary lithium deposits at the present stage,three major characteristics are summarized :① sedimentary lithium deposits mainly divided into three types:volcanic clay type,carbonate clay type/ associated type and jadar type. They are mainly distributed in North America,South America,Europe and Asia. Its metallogenic age is mostly in the Cenozoic era,and part of the sedimentary lithium ore associated with bauxite and coal system was formed in the Paleozoic or Mesozoic era. ② Volcanic clay lithium deposits are mostly formed in the closed lake-phase sedimentary basin,the mineralization material mainly comes from volcanic magmatic activities. The main sources of lithium in Jadar- type lithium deposits are river sediments and volcanic eruptions in different periods. The lithium in carbonate clay-type/ associated lithium deposit mainly originates from the sedimentary environment,and its enrichment process is mainly related to weathering and sedimentation. ③ In volcanic clay type lithium deposit,lithium mainly occurs in Li-smectite,hectorite and illite; The mineral composition of carbonate clay type/ associated type lithium resources is different,and there are three types of lithium occurrence states:① occurs in the lithium chlorite interlayer hydroxide layer;② occurs in the illite structure octahedral or pseudohexagonal ring;③ occurs in the kaolinite structure octahedral. In Jadal type lithium deposits,lithium mainly exists in the crystal structure of the independent mineral Jadarite. Finally,this paper provides prospects for the research direction and exploitation prospects of sedimentary lithium resources in China,which provide support for geological exploration and efficient development of lithium resources in China.

Advancements and Future Prospects of Dust Control Technology for Occupational Hazards in Metal Mining,Loading and Transportation in China

LI Gang, LI Sheng, ZHANG Weijun, XU Yu, CHEN Yanting　

2024, 53(5): 41.

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Among the main occupational disease hazards in metal mines,such as high temperature,noise,dust,toxic and harmful gases,dust caused pneumoconiosis accounts for the largest proportion of occupational disease cases. In order to continuously promote the research on occupational health protection of dust and ensure the safety of personnel,production and environment in metal mines,this study summarized the theory of dust source and diffusion in metal mines as well as the research status of dust occupational health and protection. Based on the systematic principle of safety engineering,it analyzed the technical progress of dust occupational hazard prevention and control during mining,loading and transportation of metal mines in China from three dimensions:source control,process control and individual protection. On the basis of the above analysis,the paper analyzes the existing shortcomings and looks forward to the future development direction. It is believed that the existing deficiencies at this stage are that the theoretical system of metal mine dust control is not mature,the research on intelligent monitoring and early warning technology of metal mine dust needs to be strengthened,the cross-cutting and collaborative research and application of different dust control technologies are weak,and the research and development of individual respiratory protection equipment oriented on the comfort of on-site personnel needs to be further strengthened. In the future,further work can be carried out from improving the theoretical system of dust control in metal mines,developing intelligent dust monitoring and early warning technology applicable to the dust production characteristics of metal mines,focusing on the cross line of dust control technology,collaborative research and application,and developing more ergonomic personal protection equipment.

Study Status and Prospect of Mine Dust Occupational Hazard Risk Assessment

XIAO Shuangshuang, LIU Jin, LI Weiyan, MA Yajie

2024, 53(5): 55.

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The occupational hazard of mine dust has become the most important occupational health problem in the mining industry. Risk assessment and quantification of mine dust hazards are the focus of mine occupational health work. In order to deeply understand the study context of mine dust occupational hazard risk assessment,based on the perspective of bibliometrics, VOSviewer and CiteSpace software were used to visualize the literature on mine dust hazard risk assessment collected by CNKI and WOS (Web of Science ). High-frequency keywords were extracted,and keyword co-occurrence and cluster analysis were carried out to obtain the time series characteristics,study subjects and hot frontiers information of the literature. According to the results of visual analysis,the risk assessment indicators,hazard level and assessment methods are analyzed and elaborated in detail. The risk assessment process is refined,the physical and chemical characteristics and hazard factors of mine dust were analyzed,and then the risk assessment indicators were summarized. The classification of dust occupational hazards was summarized. According to the three categories of qualitative,quantitative and comprehensive assessment,the risk assessment methods of mine dust occupational hazards are sorted out,and the quantitative model of health injury risk assessment is explained. The study results show that:at present,a lot of in-depth study and practice have been carried out in the field of mine dust occupational hazard risk assessment at home and abroad,and the assessment work has achieved remarkable results. However, the dust in various production links of mines is still difficult to completely curb,the theoretical mechanism of related study is not yet mature,the influencing factors of evaluation indicators are complicated,the classification of hazard degree lacks basis, and the evaluation methods have subjective uncertainty. The risk assessment system of dust occupational hazards in mines needs to be systematically studied,and the risk analysis and early warning platform of dust hazards still needs to be explored and constructed. In the future,it is necessary to further improve the relevant laws and regulations on the risk assessment of occupational hazards of mine dust; Select risk assessment indicators scientifically and reasonably, simplify the assessment process,and achieve good practical benefits;Break through the limitations of existing methods,a suitable data information theory risk assessment model is established to provide an effective basis for mine dust control;Actively apply new technologies such as cloud computing and big data to realize the construction of dust monitoring-risk assessment-intelligent prevention and control integrated system.

Current Situation and Prospect of New Energy Redevelopment of Closed / Abandoned Mine Land Resources in China

HAO Xianjie, SONG Sitong, TANG Kuanxu, GUO Yong, DING Zhijie

2024, 53(5): 68.

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After the closure or abandonment of mines,a large amount of land resources will be generated,such as the pits and waste disposal areas of open-pit mines,as well as the ground squares and the subsidence areas of underground mines. Land resources are one of the most important natural resources in China,and the land resources of closed/ abandoned mines are relatively abundant. However,due to the adverse effects of mining,the issue of redevelopment and utilization of these land resources is an important challenge faced by closed/ abandoned mines. In response to the shortcomings of the current utilization for such land resources,the current development status of combined development and utilization of closed/ abandoned mining land resources with wind energy,light energy,forestry,agriculture,and animal husbandry at home and abroad is analyzed at first. A scientific and technological system for the development and utilization of closed/ abandoned mining land resources in China is proposed,namely the "wind-forest-light" new energy complementary redevelopment model of land resources. The technical factor evaluation standards and transformation scheme system under different conditions is studied,and the problems and difficul-ties in the current development and utilization of closed/ abandoned mining land resources in China is summarized. Five basic thoretical and five pending technical difficuties that need to be overcome in the implementation process is condensed,and the corresponding policy measures and future development prospects is put forward. The study results show that:① The redevelopment of new energy resources from closed/ abandoned mining land is an emerging,limitless potential new discipline that requires cross disciplinary cooperation across multiple fields. Ground resources are the carrier,and the state of the carrier after mining is the core. The application of new energy in all directions is the goal;② The redevelopment of new energy for the closure/ abandonment of mining land resources is not only an important measure to achieve sustainable utilization of land resources in China,but also an important direction for developing new energy to help achieve China′s "dual carbon" goals. At the same time,it is also an important measure to achieve the transformation of closed/ abandoned mines. On the basis of further improving this model,it is necessary vigorously promote the comprehensive development and utilization of new energy for the closure/ abandonment of mining land resources.

Study of Changing Characteristics on the Mechanical Environment of the Surrounding Rocks during the Transition Period of Tungsten Mining in Sharply Inclined Vein Group

ZHONG Wen, LIN Shengjie, OU Fei, QIU Jinming, ZHANG Zequn, ZENG Bing, ZHAO Kui

2024, 53(5): 76.

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With the development of modern mining techniques,the steeply inclined vein deposits are transitioning from the traditional shallow hole mining method to the large section stage caving method. This change has altered the disturbance pattern of the rock mechanics environment,especially during the transition period when the two mining methods are replaced, which may result in a blind spot in the distribution pattern of the rock mechanics environment in the mining area. This paper simulated the changing characteristics of the surrounding rock in the transitional mining section using FLAC3D software based on the initial ground stress field determined by acoustic emission measurement. The results show that:① After the upper mining area is mined out by the shallow hole mining method,the surrounding rocks of the upper and lower plates of the mining area are subject to tensile stress and there is a tendency for the side gang of the mining area to be loosened,and the surrounding rocks between the single vein mining areas are subject to uneven stress leading to staggered distribution of the displacement of the upper and lower ends,and the surrounding rocks of the upper and lower plates of the mining area and the surrounding rocks between the single vein mining areas are mainly in the shear plastic zone,with the risk of shear damage. ② After the lower mining area is mined out by the large section stage caving method,the stress concentration phenomenon in the mining area is more obvious,the top plate of the mining area has a tendency to settle,the surrounding rocks of the upper and lower plates of the mining area are deformed in the vertical direction and the displacement of the two mining areas is more continuous,the top and bottom plates of the mining area are mainly tensile plastic zone and there is a large range of shear plastic zone in the surrounding rocks of the upper and lower plates,which indicates that the surrounding rocks of the mining area may have the risk of tension and shear damage at the same time. ③ The timely filling of waste rock in the quarry area can effectively suppress the stress concentration phenomenon. The mine should strictly control the timing of mining and filling of the adjacent quarries above and below when mining the transition area to avoid over mining,thus maximally suppressing the adverse effects of surrounding rock deformation and destabilization caused by stress concentration.

Arching Characteristics and Boundary Weakening in Block Caving of Hard Orebodies

HUANG Minqing, ZHANG Houyuan, GUO Xiaoqiang, ZHENG Qiwei, LIU Qingling

2024, 53(5): 84.

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During block caving of hard rock orebodies,the pressure arch of the caving back intensifies the stress concentration at the caving boundary,and the caving process is easily hindered by the restraint on both sides of the arch feet. By calculating the ultimate self-stable balance of the pressure arch at the caving roof and analyzing the characteristics of the arch formation and the potential areas of caving cessation through numerical simulation,the engineering measures for pre-conditioning of hard rock by boundary weakening is proposed. The arching coefficient and caving damage factor are introduced to characterize the annual development trend of the plastic zone above the undercutting in different areas of the rock mass,and the relative position of the plastic zone is used to reflect the position and timing of slot cutting,thereby ascertaining the timeliness of boundary weakening. The results show that during the upward caving process of hard rock masses,the caving roof is prone to forming a self-stable arch,which causes the caving to slow down or cease. The vertical and horizontal pressures at the top of the caving back are the direct factors causing the continuous destruction of the pressure arch. As undercutting advances,the span of the caving pressure arch increases at a non-uniform rate,and the boundary of the pressure arch continuously moves forward with the advance of the undercutting,and the area in front of the undercutting line is always in a high stress concentration condition. When the plastic zone at the ore-rock boundary appears later than the undercutting forward line,slot cutting can be used to destroy the balance of the caving arch and promote propagative caving. The study results are helpful for determining the area and timing of boundary weakening of hard rock masses in block caving.

Experimental Study on Safe and Low Loss Recovery of Metal Mine Legacy Ore Pillars Based on HSCA Static Rock Breaking

GONG Cong, XU Yongbin, LIU Chang, QI Yanshun, HUANG Zhihao, ZHAO Kui, ZENG Peng

2024, 53(5): 92.

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Aim at the use of blasting to mining legacy ore pillars in metal mines has the limitations of poor safety and high ore loss rate,High Range Static Cracking Agent (HSCA) which has no vibration characteristics is introduced into the mining of legacy ore pillars. Through the design of HSCA expansion compressive stress tests and static rock breaking tests,the magnitude of HSCA radial expansion compressive stress and its distribution pattern in relation to the water-cement ratio were analyzed,and the feasibility of achieving the safe and low-loss mining of legacy pillars in metal mines through HSCA static rock breaking was demonstrated from the characteristics of the distribution of the expansion compressive stress,the method of controlling the orientation of the main crack,and the timeliness of rock breaking,respectively. The results show that when the water- cement ratio is larger than the theoretical optimum water-cement ratio,the expansion compressive stress decreases with the increase of the water-cement ratio. For an upwardly inclined borehole,the expansion compressive stress tends to increase from the bottom of the borehole towards the mouth of the borehole. Conversely,for a downward inclined hole,the expansion compressive stress tends to decrease. By using HSCA static rock breaking,the main crack direction of the legacy ore pillars can be controlled by pre-cutting slots in the charge holes,adding induced sheet or induced holes,which can effectively reduce the re-injury of the non-rock-breaking area of the ore rock. Therefore,for the areas where blasting is not suitable for mining the legacy ore pillars,using HSCA static rock breaking is not only conducive to ensuring the safety of legacy pillar mining,but also improves the legacy pillar mining rate. The study results can provide reference for further exploring the new rock breaking theory and technology of mining the legacy ore pillars in metal mines.

Prediction Model of Explosive Unit Consumption in Open-pit Mine Based on Zoning of Blasting Compliance Method

YU Qinglei, LI You, LI Wantao, WU Jiawei, WANG Yuheng, JIN Rijie

2024, 53(5): 102.

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Blasting operation in open-pit mines requires uniform blasting fragmentation of ore and rock. Evaluation and application of blastability of rock mass is an important basis for optimizing blasting design and improving blasting effect. Based on the inductive analysis of the main factors affecting the blastability of rock mass,cluster analysis and correlation analysis are carried out on the physical and mechanical characteristic parameters and joint geometric parameters of ore and rock in 15 blasting areas of Sijiaying Iron Mine. The results show that tensile strength,rock density,integrity coefficient of rock mass and average distance of joint,can be used to evaluate the blastability of rock mass. At the same time,BP neural network optimized by ant colony optimization is used to give weight to the evaluation index,an appraisement method for zoning of blasting compliance of rocks in open-pit mine based on weighted clustering analysis is proposed. Then,using the information of boreholes and the geological model,the inverse distance interpolation method is adopted to get a block model of zoning of blasting compliance of ore and rock. The mathematical model of unit explosive consumption based on blasting zoning index is established by using multiple regression analysis method,which can provide reference for the subsequent blasting design of ore and rock in blasting areas under similar working conditions and is of guidance significance to the optimization of blasting design.

Study on the Influence of Dust Extraction Parameters on the Diffusion Law of Dust Pollution in the Fully Mechanized Excavation Face of Rock Roadways

NIE Wen, LIU Qiang, HUA Yun, PENG Huitian, GUO Lidian, CAI Yuankun

2024, 53(5): 110.

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The dust extraction system is an important component of controlling dust pollution in the long-pressure shortsuction ventilation method of the rock roadway fully mechanized excavation face,and the determination of appropriate dust extraction parameters is the key to achieving effective dust removal. The soft of Solidworks was used to establish physically model the 632 fully mechanized excavation face of a rock roadway in a certain mine,and ICEM-CFD mesh division was carried out. The subsequent mesh model was confirmed through grid independence testing. The computational fluid dynamics software FLUENT was used to numerically simulate the influence of different dust extraction positions Dn (n = 0,1/4,1/2,3/4,1) and exhaust air rate (300~350 m3 / min) on the dust pollution diffusion. The accuracy of the numerical simulation results were verified through simulation experiments. The results show that when the dust extraction positions are D0,D1/ 4,D1/ 2,and D3/ 4,respectively, the overall airflow in the roadway is in a relatively chaotic state. The dust pollution transported by the airflow eventually diffuses to the entire roadway. When the dust extraction position is D1,with the combined action of exhaust and compressed air,an effective dust control wind curtain with wind direction pointing towards the roadway head,uniform flow,and covering the entire cross-section of the roadway is formed within a range of 4. 6~6 m from the roadway head. Dust pollution is controlled by the air curtain in the enclosed space between the excavation machine driver and the roadway head. When the exhaust air rate are 330 m3 / min or above,an effective dust control air curtain is formed at the driver′s location. However,in order to minimize energy consumption while effectively controlling dust pollution,the optimal exhaust air rate is selected with the minimum value of 330 m3 / min.

Study on Dust Pollution Law and Multi-section Fog Curtain Dust Control Technique at Transfer Point of Inclined Roadway

JING Deji, BAO Chunhua, LIU Hongwei, KAN Qisheng, DU Pengyu

2024, 53(5): 118.

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In view of serious dust pollution problem in sloping road transfer point,the geometric modelling of the No. 3 transfer point of Qipanjing Coal Mine was carried out by using COMSOL software,and based on the particle tracking model of Computational Fluid Dynamics (CFD),finite element method,and k-ε turbulence model,the distribution of wind flow streamline, the distribution of velocity multicut section and the trajectory of dust particles in the No. 3 transfer point were computed, the changes of wind flow and dust transport law were investigated in the No. 3 transfer point during production work. The wind flow changes and dust transport law at the No. 3 transfer point during production work are studied,and a multi-section fog curtain dust control technology is proposed,which is based on principles of spiral fog curtain dust control and supersonic dust isolation, can form a long-distance and wide coverage fog curtain to wrap dust particles to maximum extent to achieve highly efficient purification of dust,and finally,through dust control experiments and on-site application of the technology at No. 3 transfer point of Qipanjing Coal Mine,the high efficiency of this technology in terms of dust reduction characteristics and reliability are verified. The study results show that:the wind flow distribution is mainly affected by combined effect of belt speed,traction and induced airflow,and is distributed in layers along horizontal and vertical directions,forming a dense vortex with an average speed of 0. 5 m/ s. Dust is easily affected by vortex spreading in all directions,it is mainly distributed on downwind side,the particles of sizes between 5 μm and 15 μm are more susceptible to diffusion of wind flow,and are gathered in height of the workers′ respiratory zones,which is seriously contaminated. After the dust control experiment and on-site application of this technology,the dust reduction efficiency of whole dust and exhaled dust is as high as 93. 65% and 85. 59% respectively.

Study on Semi-enclosed Area Joint Dust Control Technology of Comprehensive Excavation Face

SI Junhong, WANG Haoyu, HUO Xiaoquan, YUE Dong, YUAN Zengyun, FAN Zhihai

2024, 53(5): 126.

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To effectively improve the dust reduction efficiency of comprehensive excavation face and overcome the limitations of a single dust reduction mode,a simulation model of comprehensive excavation face is established,and the reliability of the simulation results is verified by field measurement results. The wind flow field and dust diffusion and migration law of comprehensive excavation roadway are studied,and the characteristics and distribution range of high-concentration dust accumulation are obtained. The results show that the main dust generation source is at the head of comprehensive excavation face,and the concentration of dust gradually decreases during the diffusion process to the roadway outlet. The dust migration traces are basically consistent with the wind speed vector. Under the influence of roadheader,the dust flow forms a vortex above the fuselage, accumulating in large quantities at the driver′s position and forming a large range of backflow settlement area behind the roadheader,which can easily cause secondary dust and pollute the roadway return air area. Based on this,the principle of regional division is proposed,determining the head-on,roadhead,driver′s position,dust return area above the belt,and the range beyond 15 m from the head-on as the key dust removal areas. A semi-enclosed regional joint dust control technology combining single-area targeted dust removal and multi-zone combined dust removal is developed. A complete set of comprehensive dust control equipment is designed,composed of annular spray,air curtain dust separation device,dust removal fan,scattered fog curtain,and full-section spray. The field application results of the 42221 working face of Chaijiagou Well in Yuhua Coal Mine show that the average dust reduction rate of the roadway is 88%,and the dust reduction rate of the driver′s position is 86%.

Study on the Whole Process Intelligent Mining Architecture and Key Technologies of Open-pit Mines

QU Fuming, WANG Huaiyuan, LIU Xiaobo, YUE Xingtong, MA Yipeng

2024, 53(5): 134.

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In response to the three major difficulties in system planning,system intelligence,and system collaboration in the current intelligent construction process of large metal open-pit mines,study and application of the intelligent mining architecture and key technologies for the entire process of large metal open-pit mines have been carried out. Based on the entire process flow of intelligent and safe mining in large metal open-pit mines,an overall architecture of intelligent mining in large metal open-pit mines,including "three platforms,four levels,and four plates" was constructed. A full process intelligent and safe mining framework for five production processes,namely perforation,blasting,mining and loading,transportation,and unloading was designed,and the multi-link and serialized key technologies of intelligent mining,including intelligent perception of equipment status and operating environment,intelligent navigation and equipment behavior planning,and intelligent equipment core control are proposed. The study results have been successfully applied to Qidashan Open-pit Iron Mine,and relevant technologies have been demonstrated and applied using the 3D simulation system,intelligent command and dispatch system,and remote control system of drilling rigs in the intelligent production of Qidashan Mine as examples. In the end,intelligent safety applications with multiple scenarios,links,and processes were achieved in Qidashan Mine,forming a large-scale metal open-pit intelligent mining model of "full process planning,multiple operation intelligence and multi-scene linkage". This solves the key common theoretical and technical difficulties of intelligent open-pit mining,and has certain reference significance for the intelligent construction of open-pit mines in China.

Development and Application of a Sliding Equipment System Based on Single-pulse Scanner and Rangefinder for Pile Inventory

XU Zhihua, PENG Yuanhang, LIN Jiaxuan, LU Xingzheng, XIA Lin, LIN Rongchuan, LIANG Yanbin

2024, 53(5): 144.

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Enhancing the level of informationization in mine surveying is the critical foundation for intelligent mining. The plant storage is the important place for managing the production of minerals. As a result,a timely and accurate pile inventory within the plant storage is crucial for the planning of mineral production. However,due to the intricate operational conditions and restricted accessibility to workers,the traditional surveying techniques have challenges in acquiring comprehensive geometry of the pile surface. Consequently,this leads to inadequate accuracy and low efficiency in conducting pile inventories. In order to address the aforementioned issue,a novel sliding equipment system is proposed for on-line pile inventory. The developed equipment combines the vertical coordinates obtained through single-pulse scanner with the horizontal coordinates acquired by a rangefinder. This equipment enables integrated online processing of 3D point cloud acquisition,digital surface model construction, and pile volume calculation,with adaptability to expand hardware integration methods according to specific requirements. Additionally,it supports the development of functionalities such as visualization. Experiments were undertaken at the Zijinshan Gold and Copper Mine concentrator to analyze the effectiveness of the proposed equipment system for pile inventory. The primary emphasis of these experiments was to evaluate the pile volume measurements. The experimental results indicate that the developed equipment has the capability to perform online pile inventory with a repeatability of above 99%. Further-more,when compared to on-site weighting measurement,the developed equipment exhibits an accuracy that exceeds 99%. The scanned point cloud exhibits superior quality and the data processing efficiency surpasses that of commercial scanners,such as GEO-SLAM. In forthcoming endeavors,the developed equipment will offer technical assistance in various domains,including volume estimation of open-pitm mine,construction of three-dimensional geometries,quantification of the exposed mining heap, and real-time loading inventory of vehicles. These functionalities hold immense importance in the establishment of intelligent mining operations.

Performance Analysis of Cold Load / Storage Backfill Cooling System Based on Solar Adsorption Refrigeration

WANG Mei, WEN Guoming, LIU Lang, NI Wanying, LI Jiahui

2024, 53(5): 152.

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The load/ storage filling cooling with ice particles is an effective way to solve the problem of thermal damage in deep Wells,but its ice production energy consumption is large and the system operation cost is high. For this reason,Mine Cold Load/ Storage Backfill Cooling System Based on Solar Adsorption Refrigeration was developed. The system consists of surface solar heat collection subsystem,adsorption refrigeration subsystem and underground ice delivery subsystem. Through the establishment of the mathematical model of the subsystem and the TRNSYS model of the ground system,the variation rules of the methanol resolution capacity,adsorption refrigeration capacity and adsorption ice production capacity under the influence of different solar radiation intensity,different seasons and different regions were analyzed respectively,and it was concluded that the solar radiation intensity and solar continuity were the main reasons for the difference of the ice production capacity. Huainan and Nanning regions with superior solar radiation intensity and solar continuity were selected to analyze the ice making energy efficiency of the developed system. The results show that compared with the traditional steam compression refrigeration system, the average energy saving efficiency of the adsorption refrigeration subsystem of the system reaches 64. 71%. The research results show that the research and development of a new mine cooling system combining solar adsorption refrigeration with load/ storage filling cooling is beneficial to efficiently solve the problem of mine thermal damage.

Study on the Stability and Acoustic-Mechanical Characteristics of Rock Slopes in Open-pit Mines under the Influence of Rainfall

CHEN Jie, MENGLI Deren, PU Yuanyuan, CUI Yi, YANG Ni, ZHU Chao, LIU Bo, ZHANG Dingshan

2024, 53(5): 161.

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Rainfall is an important factor in exacerbating rock slope disasters in open-pit mines,and accurate analysis of the acoustic-mechanical characteristics of rocks under the influence of rainfall is a prerequisite for implementing mining safety monitoring. In order to investigate the influence of rainfall on the stability and acoustic-mechanical properties of rock slopes in open-pit mines,this paper mainly uses indoor acoustic and mechanical tests as the main means to study the acoustic emission signal characteristics of sandstone during water saturation under different probe layout methods,and quantitatively analyze the acoustic emission characteristics of rock sample failure and its failure modes in dry and saturated states. Results show that: ① Rainfall significantly attenuates the acoustic emission signal,with a decrease of about 43. 3% in the maximum amplitude and about 33. 3% in the waveform frequency at all probe locations,exhibiting a significant " frequency shift" phenomenon; ② The acoustic emission events show a relatively random and mild manner in the process of dry rock sample failure,while they show a certain continuity and concentration in saturated rock samples;③ The failure mode of both dry and saturated rock samples is mainly shear failure,accompanied by some tensile failure,but the tensile failure in saturated rock samples is more obvi-ous. The study results can provide reference for the study of the sound-mechanical characteristics of rock slope in open-pit mines,and promote the application of microseismic monitoring technology in the stability monitoring of open-pit mine slope.

Damage Characterisation of Phosphorites under Different Water Contents and Stresses

LIN Manqing, FENG Lei, SUN Junyang, PENG Yali, ZHANG Anqing, JIN Shengli

2024, 53(5): 169.

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Underground phosphate mines are subject to long-term groundwater erosion,and water-rock interaction is a common problem in underground mining engineering,which can easily induce geological disasters under excavation disturbance. In order to investigate the damage characteristics of phosphate rock under different water-rock interaction,uniaxial loading test of phosphate rock with different water content was carried out with the help of acoustic emission instrument. The macroscopic damage characteristics and mechanical properties of phosphate rock under different water content states were analysed, and a model of the internal damage variables in the specimen was constructed with the help of acoustic emission ring counting characterisation. The above study results show that:① Water has a weakening effect on the cemented materials in the phosphate rock,which in turn has a deteriorating effect on the mechanical properties of the phosphate rock;② Water affects the damage mode of the phosphate rock,and with the increase of water content,the damage mode of the phosphate rock changes from brittle to plastic damage,which is manifested by the fact that the peak strain of the specimen of the phosphate rock increases with the increase of its water content;③ As the water content of phosphate rock increases,the time lag of acoustic emission from loading to damage is relatively longer,and the acoustic emission ring counts and energy gradually decrease;the evolution of internal damage variables of phosphate rock with different water content is synchronous with the whole loading process of the rock samples. The above study results can provide theoretical reference for the safety mining of underground phosphate mines.

Study on the Mechanism of Charge Jet Penetration and Damage Induced Cracking in Deep Shale Reservoirs

LUO Ning, CHAI Yabo, MOU Gongyu, WANG Yiming, WANG Lujia

2024, 53(5): 179.

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In order to study the influence of in-situ stress on the penetration of shaped jets into shale reservoirs,a quasitwo- dimensional model of shaped jets penetrating shale under different confining pressures was established,and the shale confining pressures loaded by dynamic relaxation method were 0,10,20 and 30 MPa,respectively,and the fracture mechanism of shale damage caused by jet penetration was systematically analyzed from the aspects of perforation depth,shale pore fracture formation law characteristics and stress changes at monitoring points. The results show that the damage area of shaped jet after penetration into shale can be divided into complete failure zone,compression-shear failure zone and tensile failure zone,and the failure area decreases due to the increase of confining pressure. The penetration depth of shale without confining pressure is 600. 3 mm,and the penetration depth of shale under 10,20 and 30 MPa confining pressure decreases to 524. 3,454. 3 and 446. 1 mm,respectively,with a reduction range of 12. 66%,24. 32% and 25. 69%,respectively. The peak pressure of shale perforation decreases rapidly with the increase of the distance from the center of aperture,and the attenuation rate gradually decreases from fast to fast,and decreases gradually with the increase of the distance from the starting point of penetration,and the decreasing trend is approximately linear.

Experimental Study and Application of Dynamic and Static Mechanical Properties of Concrete with Different Steel Fibre Types

LI Diyuan, WANG Mimi, WANG Yongbing, FANG Xugang, JIANG Jingtai, YU Yisong, WANG Xiaodong

2024, 53(5): 190.

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Based on the background of steel fiber concrete lining support for deep shafts in Yunnan Province. Cement, steel fibers,and waste gangues from the deep mine were utilized as raw materials to prepare steel fiber concrete samples. The dynamic and static mechanical properties of concrete with different steel fiber types have been investigated. The dynamic and static mechanical properties of steel fibre concrete and failure modes were obtained by uniaxial compression tests,Brazilian splitting tensile tests and dynamic compression tests. Furthermore,the crack evolution in steel fiber concrete was studied by using high-speed cameras and digital image correlation (DIC) method. The results show that the compressive strength of concrete mixed with three or double types of steel fibers is higher than that of concrete mixed with single types of steel fibers. The concrete mixed with three types of steel fibers is the most effective on increasing the tensile strength of the concrete. The dynamic compressive strength increases with the addition of steel fiber types. Surface cracks appeared later in steel fibre concrete specimens compared to plain concrete. The more types of steel fiber mixed,the higher the peak strain of the steel fiber concrete specimens. Plain concrete exhibits brittle failure characteristics,and steel fiber concrete shows ductile failure behavior. The concrete mixed with three types of steel fibers is used in mine shaft lining support,which effectively improves the integrity and stability of the shaft wall and provides a guarantee for the safety and high efficiency of the deep mining engineering.

Study on the Influence of Freeze-thaw Deterioration of Surrounding Rock on the Stability of Tunnel in Seasonal Cold Area

FENG Qiang, ZHAO Zidong, LIU Haitao, LIU Weiwei, WANG Hongbo, ZHANG Xinpeng, ZHANG Qiang

2024, 53(5): 199.

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The freeze-thaw damage of surrounding rock will cause the deformation pressure of lining to increase,which will adversely affect the stability of lining,which is a key problem in the research of tunnel engineering in seasonal cold area. In this paper,the stress-strain curves of sandstone under different freeze-thaw cycles and compression tests are obtained,and then the deformation parameters and strength parameters of surrounding rock are obtained from the stress-strain curves. Finally, the change rule of rock mechanics parameters is embedded into ABAQUS software to numerically analyze the long-term stability of the tunnel under freeze-thaw cycle,and the stress field and displacement field of surrounding rock and lining under 0,6,12, 18 and 24 cycles of freeze-thaw cycle are obtained respectively. The results show that:① With the increase of the number of freeze-thaw cycles,the maximum and minimum principal stresses on the surrounding rock decrease linearly;② The maximum principal stress,the minimum principal stress and the displacement of the lining increase exponentially;③ Compared with the condition without freeze-thaw,the maximum and minimum principal stresses of surrounding rock after 24 freeze-thaw cycles decreased by 43. 69% and 20. 66%,respectively;④ The maximum principal stress,minimum principal stress of lining and maximum settlement of vault increased by 13. 64%,15. 75% and 49. 36% respectively. In the design of tunnel support in cold area, it is necessary to consider the problem that the self-stability of surrounding rock attenuates under freezing and thawing action, which leads to the increase of the force of supporting structure.

Study on Bench Precision Blasting Delay Time Based on SPH-FEM Coupling Algorithm and Its Field Application

SHI Wenqiang, WANG Sijie, DU Wenxiu, BAO Yinjiya, YANG Xu, GONG Min, GAO Yuhang

2024, 53(5): 210.

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Study on Parameter Optimization of Roadway Bolt Support in Joint-developed Area

LÜ Jingye, WANG Meijun, LI Sheng

2024, 53(5): 220.

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