Current Issue
2025 Vol. 53 No. 1
Coal mine intelligentization is a vital direction for promoting the high-quality development of the coal industry. Reviews advancements in the foundational theories, technological systems, and demonstration applications of coal mine intelligentization, comprehensively analyzes the current status of intelligent coal mine construction, identifies key technological bottlenecks, and proposes pathways to address these challenges. In terms of foundational theories, the study focuses on the theoretical framework of digital coal mines and intelligent mining. For technological system construction, the key technical modules of intelligent coal mines are summarized. Regarding demonstration applications, typical intelligent mines are used as case studies to evaluate the application effects of intelligent systems in actual production and to identify technical, managerial encountered during their promotion. Building upon in-depth research into the foundational theories and technological systems of coal mine intelligentization, as well as practical experiences from demonstration mines, the study systematically examines the current status and pressing issues in intelligent geological support, information and communication systems, excavation, mining, and intelligent safety control systems. Special attention is given to addressing technological bottlenecks in efficient excavation under complex geological conditions, high-efficiency mining of thin coal seams and seams prone to dynamic pressure, robotic collaborative operations, and system maintenance. The research highlights the development of efficient excavation technologies for complex conditions, high-performance mining techniques for thin coal seams and dynamic-pressure coal seams, critical technologies for coal mine robotics, and innovations in next-generation intelligent safety control systems. It further emphasizes accelerating the large-scale and intelligent transformation of open-pit coal mines, improving the standardization of intelligent mine operation and maintenance systems, and facilitating iterative upgrades to intelligent systems. Driven by industry needs and guided by technological innovation, the study advocates for the integration, advancement, and digitalization of coal mining equipment to provide reliable technological and equipment support for the high-quality and sustainable development of coal mine intelligentization.
There is a large amount of coal resources that are difficult to mine due to buildings, water bodies and railways in China. Conducting research on coal mining technology and liberating pressed coal under building, water body and railways are significant for improving the recovery rate of coal resources, optimizing the layout of mining and extending the service years of mines. The paper summarized the coal mining technology under buildings, water bodies and railways and buildings and structures protection technologies in China, including partial mining, filling mining, coordinated mining, overburden bed separation grouting technology and ground protection, repair and reinforcement techniques, the advantages, disadvantages and applicable conditions of each technique are also analyzed. It is proposed that the source of damage to buildings and structures caused by coal mining under buildings, water bodies and railways is the overburden destruction and surface movement. Controlling surface subsidence and studying the law of surface movement and deformation are the key to coal mining under buildings and structures. Reducing overburden failure and accurately predicting overburden failure height are the key to safe coal mining technology under water bodies (overburden aquifers). Comprehensively analyzed the law of over-burden destruction and surface movement, the prediction of surface movement and deformation, and the protection technology of ground buildings under buildings, water bodies and railways from the experience formula, theoretical calculations, and on-site measurements. Research considers that high efficiency, low cost, all solid waste, intelligent overburden grout injection and filling mining, groundwater in-situ protection and other sources of subsidence reduction technology will be the development direction of coal mining technology under building, water body and railways in the future, and establish the “space-air-ground-well” integrated monitoring and early warning mechanism of overburden and surface movement and deformation, strengthen the improvement of coal mining technology under buildings, water bodies and railways, all solid waste materials, technology and equipment level, scientifically construct and continuously improve the green low-carbon, intelligent, safe and efficient mining technology system under buildings, water bodies and railways.
The coal base in western China is the core “ballast stone” of China’s energy security. In order to improve the resource recovery rate, the stability of small coal pillar open roadway is widely used. In this paper, the mechanical model of small coal pillar open roadway is established in Meidoushan Coal Mine of National Energy Group, and the correlation between the surrounding rock subsidence of small coal pillar and the supporting force of small coal pillar is quantified. The identification model of coal pillar stability is established by using naive Bayes model to judge the stability of coal pillar before and after regulation. Through the refined three-dimensional numerical calculation, the regulation effect of small coal pillar surrounding rock in open roadway is studied, and the field implementation is verified. The results show that there is a negative correlation between the maximum subsidence of the direct roof of the open roadway and the supporting strength of the small coal pillar by constructing four kinds of overlying rock structures at different fault lines. It shows that the subsidence of direct roof can be controlled by increasing the strength of small coal pillar, and the instability of surrounding rock of roadway can be improved. A coal pillar stability identification model was established based on naive Bayes and 11 surrounding rock parameters, and the accuracy of Ac reached 0.953 7, which met the identification requirements. The original coal pillar and the modified coal pillar are identified, and the feasibility of the control scheme is proved from the algorithm point of view. Through FLAC3D numerical simulation before and after the coordinated control scheme of surrounding rock modification, the stress value of coal pillar is increased by 57.6%, and the deformation is reduced by 22.8%. The stress of the supporting body is reduced, and the maximum displacement is reduced by 31.2%. The stress difference between the two sides decreases, and the stress distribution of roadway surrounding rock becomes more balanced. The in-situ implementation of the scheme can increase the maximum stress of coal pillar to 2.325 times, and the stress fluctuation is stable, and the deformation of roof and two sides is reduced by more than 80%. The feasibility of the coordinated control scheme of surrounding rock modification to prevent and control the deformation and failure of small coal pillar open-air roadway is verified, and the stability of surrounding rock is ensured. The research results provide basic support for the scientific design of small coal pillars in open roadway in western mining area, and provide reference for the prevention and control of the instability of open roadway with small coal pillars in western mining area.
Energy-absorbing support is an important prevention and control technology in underground rock engineering to enhance the stability of surrounding rock and prevent disasters such as rock burst. The core principle of energy-absorbing support technology is to effectively absorb or dissipate energy through specific structural designs when the rock mass undergoes displacement or deformation, thereby reducing engineering failure and accidents caused by impact loads. Energy-absorbing bolts are a common form of energy-absorbing support. This technology combines the surface surrounding rock with the deep stable rock mass through bolts and generates prestress within the surrounding rock to absorb or dissipate energy and prevent mine disasters. This flexible support method is suitable for the support of various environments in tunnel and has been widely used in the prevention and control of mine disasters. This investigation reviews over 30 representative energy-absorbing bolt designs since 1968, classifying them into two major types: structure and material. It focuses on analyzing the working principles and design advantages of eight typical energy-absorbing bolts and points out the deficiencies in the application of existing energy-absorbing bolt support in terms of safety and intelligence. Combining the valuable research results of predecessors with the current demands of high-strength and intelligent support in deep mines, an intelligent early warning negative Poisson’s ratio structure energy-absorbing bolt is proposed. This bolt utilizes a negative Poisson’s ratio energy-absorbing structure to achieve an increased resistance effect and has the characteristics of bidirectional constant resistance energy absorption and bidirectional monitoring and early warning. It can meet the demands of strong resistance support and visual early warning in complex nonlinear soft rock tunnel, which is conducive to accelerating the integration of support systems and promoting the development of safe and intelligent mines. Finally, this study provides an outlook on the optimization and innovation trends of energy-absorbing bolt support equipment.
The instability of high hard roof after deep-buried and extra-thick coal seam mining causes the phenomenon of strong ground pressure to stand out, which seriously threatens mine safety production. In order to explore a new scheme of pressure relief and scour prevention, taking 8302 working face of Xinjulong Coal Mine as the research background, a scheme of pressure relief and scour prevention by combined blasting of high roadway and gateway was put forward. By combining theoretical analysis, physical simulation and numerical calculation, this paper analyzes the principle of cooperative pressure relief of high roadway blasting and gateway blasting, reveals the fracture instability mechanism of high roadway blasting pressure relief on hard roof, and clarifies the evolution characteristics of high roadway blasting on coal seam stress field. According to the field working conditions, the pressure relief and monitoring scheme of combined blasting of high roadway and gateway is designed and practiced, and remarkable pressure relief effect is obtained. The conclusions are as follows: ① The joint pressure relief of high roadway and gateway weakens the overlying strata structure, causing a large number of cracks, destroying its continuity and reducing the bearing capacity of overlying strata.② Blasting in high roadway reduces the initial caving step of high key strata from 144 m to 84 m, and the periodic caving step from 24~30 m to 12~24 m. The vertical stress of coal seam decreased from 18.1~18.3 MPa to 16.2~18.0 MPa, with the largest decrease of 11.47%, which improved the stress distribution of working face. ③ The pressure relief scheme of combined blasting along the gateway and high roadway in 8302 working face is designed. The monitoring scheme is made from the aspects of surface deformation, overlying rock stress and deep displacement of roof.④ The field engineering practice shows that the microseismic energy events of 104 J and above decreased by 64.3%, and the microseismic events gradually changed from "low frequency and high energy" before modification to “high frequency and low energy” after modification. After pressure relief by combined blasting, the deformation of surrounding rock, borehole stress and stress of anchor cable are highly sensitive to faults and irregular mined-out areas, but after entering the normal stage, the stability of surrounding rock is improved, and the pressure relief effect by combined blasting is remarkable. It provides theoretical basis and practical reference for solving the problem of strong ground pressure behavior caused by hard roof with large mining height.
Rock burst, coal and gas outburst are the main disaster sources in deep coal mining, and their disaster inducing mechanism is very complicated. So far, there has been no integrated prevention and control technology for coal mine dynamic disaster. In view of this, the mechanism of stress field, seepage field and temperature field regulating dynamic disaster and its advantages and disadvantages are expounded. From the perspective of coal and rock structure evolution, the concept of structural field is defined, the connotation of coal mine dynamic disaster structure control technology is determined, the breeding mechanism and action mechanism of coal mine dynamic disaster with the space-time evolution of structural field is revealed, and the integrated technology of coal mine dynamic disaster structure control and prevention is proposed. The multi-field coupling relationship between stress field, seepage field, fracture field, temperature field and structural field is analyzed in detail. The structural field is defined as the primary field, and the rest are the secondary sub-fields regulated by the source of the structural field. This paper analyzes the active, directional and comprehensive characteristics of structural control technology, reveals the mechanism of structural control technology to prevent and control coal mine dynamic disasters, and puts forward a dynamic disaster prevention path based on the evolution law of structural field and control technology, which includes the whole process from pre-mining structural design, structural disaster prevention and control in mining to post-mining structural restoration, so as to achieve efficient prevention and control of dynamic disasters. The research results were carried out in an industrial test in a typical rock burst mine in Inner Mongolia, and combined with the field measured data and the inversion results of coal and rock structure, it was found that structural control technology could effectively change the high-low and low-level disaster-causing rock structure of overlying rock, reduce the roof impact risk, and reduce the deformation of roadway roof and surrounding rock, which verified the high efficiency of structural control technology in the field of rock burst prevention. At the same time, a test was carried out in an outburst mine in Gansu province, and it was found that the blind drilling and extraction scheme could not meet the actual needs of the project. After the implementation of the hydraulic slit technology designed from the perspective of structural control, the cracks in the coal seam in the working face were fully developed and through the channel of gas migration, and the final measured gas content verified the accuracy of the above conclusions. The two cases verify the scientificity and rationality of structural control technology in the field of coal mine power disaster prevention and control from the perspective of rock burst and coal and gas outburst disaster respectively.
At present, longwall top coal caving (LTCC) mining is main mining method for safety and efficiency mines with extremely-thick coal seam in China. However, the deformation movement law of overlying strata on LTCC face directly affects rock pressure behavior of LTCC face, selection of hydraulic supports, and selection of top coal caving technique and parameters, etc. Based on the engineering background on LTCC face 13200 in Gengcun Coal Mine, using similar simulation test and theoretical analysis, the paper studied the whole process of deformation, movement and caving of overlying strata, their deformation zoning, and the characteristics of rock pressure behavior of LTCC face. The results show that: ① It is determined that there are multi-layer key strata on LTCC face, i.e., the lower, middle, upper and main key strata. According to the collapse instability characteristics of key strata in different layers, the whole process of deformation movement of overlying strata on LTCC face is divided into four deformation stages. Each deformation stage is related to the collapse instability of key stratum in different layers. ② After the collapse instability of the lower key strata in LTCC mining, with the continuous increase of LTCC face advancement, the middle, upper and main key strata in the fractured zone have separated from their lower strata before the collapse instability. Before the collapse of the key strata, the collapse arch is formed in its lower strata, and the height and width of the collapse arch are positively correlated with LTCC face advancing distance. ③ The collapse instability of each key stratum on LTCC face directly causes the peak stress concentration factor
In order to grasp the overburden breakage and fissure evolution law of thick coal seam mining, a three-dimensional physical similarity simulation experiment platform was built with the background of E2306 working face of Gaohe Energy, and a combination of distributed fiber optic sensing technology and borehole peeping monitoring was used to clarify the overburden breakage and fissure distribution characteristics. Combined with the thin plate bending theory, the structural mechanics model of overburden rock in the quarry was established, revealing the mechanism of overburden rock fissure induced under the influence of mining overburden rock breakage, and deducing the regional development pattern of mining fissure. The results show that: after the face is mined back, the total number of pressures is 7 times, and the development height of the collapse zone and fissure zone is 39 m and 71 m respectively, which is consistent with the field results of the face, and matches with the theoretically calculated values, which is in line with the actual situation of the mine. In the height of the collapse zone, the low near-field overburden rock is broken vertically in a “pair of fan-shaped” way, with the structural breaking movement of “towards the cantilever beam-inclined to the masonry beam” as the main, with a large number of longitudinal breaking fissures developed, and transverse horizontal shear intersecting fissures accompanied. The overburden rock is gradually broken from the bottom up, and the overburden rock in the high far field within the height of the fissure zone is transversely broken, with the structural breaking movement of “towards masonry beam-inclined masonry beam” as the main movement, and a large number of transverse horizontally tensile delaminated layers are developed. The number of overlying rock fissures in the boundary area of the mining airspace shows the change rule of increasing and then stabilizing with the advancement of the working face, and the change of the number of strike fissures is parabolic; the number of overlying rock fissures in the middle area of the mining airspace shows the change rule of increasing and then decreasing with the advancement of the working face, and the change of the number of strike fissures is saddle-type. After the overburden rock breaks and pressurizes, the central part of the mining zone continues to bear pressure, and the rock layers on both sides are sheared and damaged to form shear concave area and bearing concave area, and the scope of the area expands with the bending and breaking of the overburden rock at different layers. The development pattern of the mining fissure area evolves from an elliptical parabolic zone to an elliptical parabolic zone with concave ends, and finally to an elliptical parabolic zone with concave ends and top.
Since high coal stress is a necessary condition for the occurrence of rock bursts, timely and accurate measurement and assessment of coal stress are critical for rock burst early warning systems. Large diameter drilling is the most commonly employed method for pre-pressure relief, hazard mitigation, and stress control in rock burst prevention. The development and application of coal stress measurement-while-drilling (MSWD) technology based on large diameter pressure relief boreholes can provide substantial coal stress data from underground coal mines. Based on the coal body cutting and failure characteristics, a mechanical analysis of bit-induced coal breakage was conducted. The relationship between bit force and coal stress was studied using the bit cutting force as a link, and a mechanical model for coal body drilling was established. An inversion equation for coal body stress, incorporating multiple drilling parameters, was proposed. The accuracy of the proposed model was verified through indoor drilling experiments. A measurement-while-drilling device, specifically designed for large diameter pressure relief drilling rigs, was developed and used for field measurements in underground coal mines. Data on bit displacement, rotation speed, and torque over time were obtained, and coal stress at different drilling depths was calculated. The stress distribution pattern in the pressure relief borehole area was presented, and a comparative analysis was conducted between the drilling energy, drilling time, and coal stress data. The results show that the average error between the loading stress from indoor drilling experiments and the stress calculated from the mechanical model is 4.9%, with the maximum error being 15.7%. The field-measured coal stress increases first and then decreases with hole depth, which is consistent with the distribution pattern of abutment pressure in the coal wall. The curves of coal stress, drilling time, and drilling energy with hole depth in the same borehole are nearly identical, indicating that drilling in high-stress zones consumes more energy and requires longer drilling time. By comparing the stress of adjacent boreholes, it was found that the first drilled borehole exhibited a higher peak stress, while the second drilled borehole showed a lower peak, with the peak shifting deeper, indicating a significant pressure relief effect in the first drilled borehole. By establishing a quantitative relationship between drilling parameters and coal stress, this study enables the in-situ measurement of coal stress based on large diameter pressure relief boreholes, extends the use of large diameter pressure relief boreholes from engineering applications to stress measurement applications, realizing the integration of coal pressure relief with stress measurement and evaluation.
Aiming at the problem that the potential sliding body space of the middle end slope of the open pit mining operation is limited, and the traditional slope stability calculation method is no longer applicable, the potential landslide mechanism of the deep slope of the stope is studied by numerical simulation method, and the spatial morphological equation of the slope surface and the sliding surface in the potential sliding body is fitted. Based on the three-dimensional limit equilibrium strip division method, the bottom surface of the sliding body is divided into unit micro-strips along the transverse and longitudinal directions. The force situation of the micro-strips in different areas of the spatial position of the sliding body and the top line of the slope is analyzed. Using the equivalent idea, the mechanical effect of each row of micro-strips is superimposed, which is equivalent to the micro-strips on the main sliding line of the sliding body. The equivalent shear strength parameters on the bottom interface of the main sliding line column are obtained, so as to establish a three-dimensional stability equivalent algorithm for restricting Carry out engineering application and design to recover coal resources. The results show that the potential landslide mode of the slope with weak layer is the combination of shear layer and bedding slide. The spatial morphology of the potential sliding surface is the combination of approximately ellipsoid and inclined plane. The three-dimensional stability coefficient of slope decreases gradually with the increase of the potential sliding body's strike limited length, showing an approximate quadratic parabola relationship. In the limited space of potential sliding body, the slope stability of various landslide modes is calculated, and the three-dimensional stability coefficients corresponding to different slope angles are greater than the two-dimensional stability coefficients. In the actual design of deep coal mining step, the slope stability decreases with the continuous reduction of +843 plate width. When the local slope angle is 25.58°, it just meets the requirement of safety reserve factor 1.2. Compared with the conventional method of slope stability analysis, this method can better reflect the three-dimensional stability of slope under the effect of three-dimensional clamping support, and can provide a new idea for the safety evaluation method of this kind of slope.
Blasting in open-pit coal mine fire areas poses a threat to the safety of blasting operations. In recent decades, engineering and technical personnel at home and abroad have made some achievements in the heat stability of explosive materials, monitoring technology of high-temperature fire area temperature field, and high-temperature blasting technology, providing technical support for the design and construction of fire area blasting. However, there are still bottlenecks in high-temperature fire area blasting technology, such as intelligent monitoring of blast hole temperature during blasting construction, development of high temperature resistant explosive materials, and large-scale fire area blasting technology. In order to achieve safe and efficient blasting in open-pit coal mine fire areas, this paper summarizes and analyzes the blasting technology in open-pit coal mine fire areas, proposes a system and development direction for efficient and safe blasting technology in fire areas: constructing a three-dimensional engineering geological model of the temperature field in the fire area, using fiber Bragg gratings for full hole depth temperature measurement, developing a real-time monitoring system for the temperature field in the fire area, and realizing temperature monitoring and early warning during blasting construction process; Optimize inhibitors and flash point enhancers for high-temperature resistant explosives, optimize explosive formulations, and develop high-temperature resistant explosive materials; The selection of cooling methods and insulation materials for high-temperature blast holes, as well as the design of insulation protection devices for drug packaging; Develop a failure apparatus of charge when the temperature safety threshold is exceeded for the charge inside the hole; Design an one-way blasting network for high-temperature fire areas; The zoning adopts a construction method that combines strengthened loosening, loosening blasting, weak loosening blasting techniques, and the "three small and one long" approach; Develop regulations for blasting operations in high-temperature coal seam fire areas to achieve information and intelligence in fire area blasting. Conducting in-depth research on key technologies for open-pit coal mine fire area blasting has important theoretical and engineering value for improving the safety and efficiency of open-pit coal mine fire area blasting.
CO is an important indicator gas in the early warning system of coal spontaneous combustion. To improve the accuracy of using CO to predict the risk degree of coal spontaneous combustion in goaf under air leakage conditions, programmed temperature rise experiments is used to analyze the corresponding relationship between different indicator gases and coal temperature during coal oxidation process. Through bundle tube monitoring and tracer gas leakage testing, the impact of leakage on CO gas in goaf is determined, and the functional relationship between CO volume fraction and coal temperature in different oxygen volume fraction ranges is corrected. Using the modified function equation to calculate the CO early warning threshold of coal spontaneous combustion, combined with the early warning value of different index gases, the classification early warning system of coal spontaneous combustion in goaf under the condition of air leakage is constructed. The research results indicate that there is a characterization relationship between the sudden changes in index gas of CO, C2H4, C2H2 and Graham coefficient during coal oxidation process and coal temperature. The initial temperatures of CO, C2H4, and C2H2are 30 ℃, 120 ℃, and 230 ℃, respectively. The turning point temperatures of the Graham coefficient are 70 ℃ and 160 ℃, respectively. The relationship between CO volume fraction and coal temperature in different oxygen volume fraction ranges is exponential function. The influence range of air leakage on CO gas in goaf is 0−90 m, and the influence volume fraction is (3−39)×10−6. Under the condition of air leakage, the oxygen volume fraction range at a depth of 0−19 m in the goaf is 21%−17%, and the correction coefficient of the CO volume fraction coal temperature function is 1−3. The oxygen volume fraction range at a burial depth of 19−55 m is 17%−13%, with a correction factor of 4−7. The oxygen volume fraction range at a burial depth of 55−90 m is 13%−9%, with a correction factor of 16−21. Based on the modified CO volume fraction and temperature function, the CO warning thresholds for coal spontaneous combustion process in different oxygen volume fraction ranges are calculated to be (50−150)×10−6, (190−330)×10−6, and (330−430)×10−6, respectively. Combined with the early warning value of CO, C2H4, C2H2 and Graham coefficient index, the coal spontaneous combustion is divided into five warning levels of gray, blue, yellow, orange and red. The research results can provide reference for the prediction and prediction of spontaneous combustion of residual coal in goaf of similar working face.
In the process of coal mine transport belt fire, CO and smoke are mainly produced, and CO as the indicator gas is susceptible to interference. When smoke is produced, it indicates that the conveyor belt has reached a high temperature, which risks missing the optimal time for extinguishing fires and ensuring personnel safety. To address this issue, an innovative method is proposed to modify the cover layer of conveyor belt using the thermo-sensitive material. This physical modification involves implanting the thermo-sensitive material to the belt. To evaluate the effectiveness of this modification, tests are conducted using a temperature-programmed oxidation furnace, a comprehensive thermogravimetric analyzer and the conveyor belt roller friction testing device to measure the changes in initial temperature, gas production rate, and volume fraction of indicator gases before and after the modification. Experimental results demonstrate that the physical modification with the thermo-sensitive material has minimal impact on the structural strength of the conveyor belt, and does not increase the risk of fire occurrence or spread. The unmodified transport belt produces CO as an early indicator gas at around 110 ℃, but its volume fraction and release rate are low, making it susceptible to misjudgment due to the presence of CO from other sources in the mine. The modified transport belt, on the other hand, detects the decomposition of the thermo-sensitive material in the belt's cover layer, generating the indicator gas that do not naturally occur in the mine at temperatures of 70~80 ℃. Compared to the unmodified belt, the modified belt enables earlier detection of the initial indicator gas by about 30 ℃, with a higher release rate and volume fraction, making monitoring easier. Moreover, the feasibility of the physical modification method is further substantiated from the perspective of practical engineering application. The indicator gas produced by the decomposition of the thermo-sensitive material is not affected by gases generated through oxidation of other materials in the mine, ensuring timely and accurate monitoring and warning of potential fires in the conveyor belt.
The wind temperature prediction of extractive working space is an important basis for the management of underground thermal pollution. A model of wind temperature prediction in tunneling working site based on PSO−SVR (Particle Swarm Optimization-Based Support Vector Regression) was established to accurately predict the wind temperature in tunneling working site, and the advantages of the PSO−SVR algorithm were analyzed by comparing it with the Multiple Linear Regression (MLR) model and the traditional SVR model with the standardization of the parameters by the “Trial and Error Method”, and finally it was applied to wind temperature prediction and local cooling of Ji-24120 return airway bottom roadway in No.10 Coal Mine, Pingdingshan Tianan Coal Mining Co., Ltd. The results show that the PSO−SVR model has the best prediction performance, and the average error of the model is only 1.81%, which is reduced 62.6% compared with the traditional SVR model. It is obvious that the optimisation of the model parameters by PSO plays an important role in improving the fit, generalisation and prediction accuracy of SVR. In addition, based on the results of wind temperature prediction by PSO−SVR algorithm and the wind temperature requirements of “Coal Mine Safety Regulations”, calculated that the cooling capacity of Ji-24120 return airway bottom roadway is 1 083.28 kW, and using the above results for local cooling, the wind temperature of the working face is average reduced about 8.6 ℃, the cooling effect is significant, which shows the reliability and feasibility of the wind temperature prediction model of PSO−SVR.
As coal mining extends deeper, pure water jet technology is gradually unable to meet the demand for coal penetration enhancement under high stress and high coal rock strength conditions. Abrasive water jet can effectively improve the rock breaking ability of water jet, and the abrasive water jet rotary cutting pressure relief technology can achieve efficient anti permeability of high stress and hard coal seams. Jet pressure and rotation speed are important factors affecting the effectiveness of abrasive water jet rotary cutting of coal and rock. Clarifying the mechanical characteristics and laws of abrasive water jet rotary cutting of hard coal is a prerequisite for reasonably matching jet pressure and rotation speed. This article adopts a combination of numerical simulation and experimental research to analyze the influence of different jet pressure and rotation speed matching relationships on the mechanical mechanism of jet impact on the target body, and clarify the influence rules of different jet pressure and rotation speed on the cutting effect of abrasive water jet rotation. The research results indicate that the normal force generated by the high-speed impact of abrasive particles on coal and rock mainly depends on the jet pressure, while the tangential force depends on both the jet pressure and the rotational speed. The normal force and tangential force have different effects on the impact of abrasive particles on coal breaking, and together determine the effect of abrasive water jet rotation cutting coal and rock. When the jet pressure is less than 25 MPa, the cutting depth increases with the increase of jet pressure, and the rate of increase in cutting depth significantly decreases after exceeding 25 MPa. Under the condition of constant cutting time, the cutting depth of abrasive jet rotation always shows an upward trend with the increase of rotation speed. Propose to use the optimal matching coefficient
The deep coalbed methane (CBM) resources in the Ordos Basin are abundant and have great development potential, making it the main battlefield for exploration and development of deep CBM in China. Among them, clarifying the enrichment law of deep CBM and delineating enrichment sections are important foundation for CBM exploration and development. Based on the analysis of data from a number of deep evaluation CBM wells recentlyimplemented by China petroleum Changqing Oilfield company in Ordos Basin, the geological control factors and enrichment rules of deep coalbed methane differential enrichment in the basin are studied by means of mathematical statistics, model calculation and geological analysis. It has been proposed that the effects of material composition, depth, and preservation are the "three controlling effects" that affect the differential enrichment of deep CBM.The material component is the main factor controlling the enrichment of CBM, among which ash yield and coal metamorphism degree are the main parameters, low ash content, high metamorphic coal with high gas content. The depth effect is a comprehensive effect of superimposed porosity, temperature, and pressure. The porosity decays with the increase of burial depth, resulting in the free gas will tend to slow down with the increase of burial depth, and the adsorbed gas exists obvious critical conversion depth, and the critical conversion depth of total CBM content is deeper than the critical conversion depth of adsorbed CBM, which is generally in the range of
The cooperative exploration of coal and uranium deposits in coal-bearing strata has become a significant direction in the research for mineral resources, in order to improve the exploration efficiency,and save the exploration cost, the basic characteristics of coal and uranium deposits in coal-bearing strata production and occurrence are analyzed, the selection of technical means and the layout of cooperative exploration are discussed, and the cooperative exploration model of coal and uranium deposits in coal-bearing strata is constructed. The research indicates that: ① The basic characteristics of uranium deposits in coal-bearing strata are analyzed, in coal-bearing strata, the spatial distribution of coal seams and uranium deposits is characterized by uranium deposits overlying coal seams (sandstone-type uranium deposits in coal-bearing strata) or alternating coal and uranium deposits (coal-rock type uranium deposits). The primary form of uranium occurrence in coal is through organic chelation or binding, whereas in sandstone, uranium mainly exists as uranium minerals, adsorbed uranium, or uranium-containing minerals. ② According to the effectiveness of coal-bearing strata uranium deposits exploration technology means, coal and uranium deposits in coal-bearing strata exploration technology means can be divided into two situations. In the completed coal exploration area, utilize the coal exploration data effectively to identify high-anomaly strata and regions based on the natural gamma logging curve, verify the uranium mineralization information of the coal measures using γ energy spectrum logging, delineate the survey area for coal measures uranium deposits, and select appropriate technical methods in phases in accordance with the technical requirements for coal measures uranium exploration. In the new area of coal and uranium deposits in coal-bearing strata exploration, the cooperative exploration technology of coal and uranium deposits in coal-bearing strata has added the effective response of radioactive technology (γ-energy spectrum logging, radon and its daughter measurement), core cataloging, penetrating geochemistry and other technical methods. ③ The layout of cooperative exploration of coal and uranium deposits in coal-bearing strata is discussed, in accordance with the standards of coal and uranium deposits in coal-bearing strata exploration and the principle of “cooperative design, cooperative deployment and cooperative construction”, the cooperative exploration of coal and uranium deposits is carried out in two situations. In the area where the coal exploration work has been completed, the high abnormal strata of natural gamma logging curves and the regional deployment of construction verification holes are selected, the survey areas of coal measure uranium deposits are delineated, and the exploration engineering is arranged in stages according to the coal measure uranium exploration standard. In the new exploration area of coal and uranium deposits in coal-bearing strata, cooperative exploration of coal and coal-bearing uranium deposits should be carried out. First, coal resources should be sought in the whole exploration area, coal exploration engineering should be arranged, and coal bearing uranium targets should be delineated in the high abnormal intervals and regions of natural gamma logging curves. Secondly, in the target area of uranium deposits in coal-bearing strata, the exploration project of uranium deposits in coal-bearing strata is mainly carried out to find uranium deposits in coal-bearing strata. ④ Based on the effectiveness of cooperative exploration technical means and the economy of cooperative exploration cost, a cooperative exploration model of coal and uranium deposits in coal-bearing strata is constructed from the aspects of cooperative exploration technical means and cooperative exploration engineering layout, which provides theoretical and methodological basis for cooperative exploration of coal and coal-measure uranium ore production.
Germanium, as a typical scarce element and important strategic metal, is widely used in fields such as optoelectronics, semiconductors, and chemicals. The exploration and development of germanium resources are therefore of great significance. Under specific geological processes, germanium can be highly enriched in coal, making coal an important source of germanium. In China, germanium-bearing coal resources are notably advantageous and are primarily distributed in regions such as Lincang in Yunnan, and the Wumuchang mining area in the Ulan Tuha and Yimin coalfields of Inner Mongolia. This paper analyzes the resource distribution and exploration status of germanium in Chinese coal, and, in conjunction with the analysis of typical coal germanium deposits both domestically and internationally, introduces the discovery processes of large to super-large coal-based germanium deposits. The paper summarizes exploration techniques and prospecting experiences for different types of coal germanium deposits. Germanium enrichment in typical Chinese coal deposits is closely related to geological processes such as hydrothermal activity and diagenesis. However, the occurrence and enrichment characteristics of germanium in coal show regional variations. Compared to coal seams, the distribution of germanium in coal is highly unstable. For the exploration of germanium-rich coal, drilling-based techniques have been established through years of exploration practice. However, further exploration is needed to improve the efficiency of germanium exploration in coal. In the future, innovations in techniques such as geochemical exploration, geological model construction, and resource evaluation are expected to promote the efficient exploration and development of germanium in coal, providing resource security for emerging industries.
To meet the geological requirements for detailed exploration of concealed anomalies in coal mines and to accurately delineate and interpret hidden water hazards around boreholes, a three-component geological anomaly localization technique using borehole transient electromagnetic methods is proposed. This technique detects geological anomalies around boreholes by transmitting high-power abnormal field signals from the surface and receiving secondary three-component field signals from the vertical borehole after shut-off. First, the Maxwell software is used to calculate the three-component responses of anomalies at various orientations around the borehole, showing that the transient electromagnetic method produces stronger three-component anomaly responses when the probe is closer to the anomaly, with different combined response patterns. This enables the qualitative determination of the anomaly’s orientation relative to the borehole. Additionally, numerical simulations of three-component responses are conducted for common anomalies in coal mines, such as water-bearing collapsed columns, water-bearing faults, and flooded goaf areas. The simulations reveal that the amplitude and shape of the three-component anomaly response curves differ due to the varying sizes and orientations of the anomaly bodies, allowing for the qualitative identification of the anomaly type. Next, the current loop inversion technique is applied to spatially localize the anomaly bodies in theoretical models of water-bearing collapsed columns, water-bearing faults, and flooded goaf areas. The results demonstrate that the three-component anomaly responses from borehole transient electromagnetic surveys can effectively localize water-bearing anomaly bodies around the borehole and provide information on their location, size, and orientation. Finally, borehole transient electromagnetic detection is conducted on a suspected collapsed column identified by three-dimensional seismic data at a mine in Inner Mongolia. Two transmitting sources at different orientations are used to excite the field, and the collected data undergoes three-component inversion. The spatial localization of the suspected collapsed column is successfully achieved, along with its size and orientation. The results of the detection are validated with advanced borehole detection during subsequent tunnel excavation. Both theoretical models and experimental data show that the borehole transient electromagnetic three-component anomaly localization technique is an effective method for detecting geological anomalies around boreholes in coal mines.
Regional treatment through surface high-pressure grouting is one of the primary prevention and control measures for safe coal mining beneath thick and loose confined aquifers. However, the high-pressure grouting process can induce movement and deformation of the overlying strata, leading to local surface uplift and structural deflection in the mining area. This phenomenon is a critical concern in the safety management of regional grouting transformations. Based on the engineering context of grouting transformations in a water-rich sandstone beneath the roof covering at working surface 120501 of a mining area in Anhui Province, this study employs numerical simulations utilizing the COMSOL Multiphysics finite element method. It investigates the process and temporal evolution characteristics of the overlying strata before and after high-pressure grouting. Furthermore, a distributed fiber optic full-section monitoring system is constructed to assess the deformation characteristics of the overlying strata at various depths and their influence on surface disturbances. The findings indicate that the regional high-pressure grouting process can be delineated into three distinct stages: “filling” “diffusion” and “disturbance”. The filling stage exhibits minimal disturbance to the overlying strata, whereas the diffusion stage generates horizontal disturbances. During the disturbance stage, significant vertical displacements are observed in the overlying strata. The influence of grouting on formation disturbance during the reconstruction process follows an increasing trend represented by a Logistic curve. The primary impact of disturbance occurs in the lower sections of the thick loose layer, with vertical arching observed predominantly in the relative water barrier section and compression occurring in the aquifer section. Monitoring results reveal that the deformation characteristics throughout the grouting process are nonlinear, with the sandy clay strata and silty sand strata identified as the primary contributors to deformation. The outcomes of full-section monitoring and numerical simulations align well. The results can offer insights and practical references for ensuring the safe operation of coal mines and effectively preventing and controlling secondary disasters triggered by regional grouting in the eastern thick loose layer covered mining area.
Water inrush in western China’s coal seam roofs is increasingly problematic due to complex geological conditions, with traditional warning methods proving ineffective. To address key challenges like indicator selection, warning methods, and standardization, research has focused on early warning theory, critical technologies, and intelligent platform development. First, a transparent hydrogeological model is introduced, building on the traditional geological model and incorporating dynamic updates. Second, based on the three-stage mechanism of water inrush development, indicator selection follows the principles of constraint, independence, and continuity. Five key factors are identified: surface water, aquifer structure and properties, aquiclude structure and properties, rock movement due to mining, and dynamic changes in hydrological elements. From these, 14 quantifiable indicators form the early warning system. Third, an intelligent early warning method is proposed using four indicators, establishing four warning levels, standards, and response measures based on accident cases, hydrological data, and standards. Fourth, an intelligent platform, integrating three layers and six core functions, is developed with a hybrid mechanism of triggers and polling for comprehensive evaluation and early warning. Finally, the platform was applied for a year in a western coal mine, issuing 15 warnings, including 10 for equipment anomalies and 5 for water inrush, all addressed with timely measures. The results validate the platform’s effectiveness. Future improvements will optimize the model and data analysis to enhance warning precision and speed.
The core of coal mine intelligence is the intelligence of comprehensive mining face, and the key to the intelligence of comprehensive mining face is digitalisation. In order to improve the intelligent level of comprehensive mining face, the academic idea of intelligent mining of comprehensive mining face of ‘coal mining is data mining’ is put forward, and five key technologies such as digital working face construction, precise cutting, equipment position detection and control, equipment group speed control and equipment group co-control are condensed, and the academic thought connotation of the idea based on the five key technologies is elaborated. It elaborates the connotation of academic ideas based on the five key technologies, and constructs the academic idea system architecture based on digital working face intelligent mining. With regard to the construction of the digital coal seam in the comprehensive mining face, it integrates the digital coal seam data, equipment group data, etc., and uses spatial interpolation algorithm and digital twin technology to construct the digital working face, constructs a database including digital coal seam data, historical cutting position and speed data, coal mining data, equipment group cooperative data, etc., and elaborates the dynamic updating method of the digital working face by integrating data from multiple sources, so as to improve the accuracy of the digital working face model. For the problem of accurate cutting in comprehensive mining face, the trajectory planning method that integrates the cutting trajectory planning data driven by digital coal seam and historical cutting position data, as well as the intelligent interpolation trajectory tracking control method based on the planning trajectory data are elaborated, and the artificial intelligence algorithm is used to carry out iterative optimization on the planning cutting trajectory data and the position interpolation data for trajectory tracking control, so as to increase the accuracy of the planning of the cutting trajectory and the control precision of the trajectory tracking. For the problem of detecting and controlling the position of the equipment in the comprehensive mining face, a precise detection method of the position of the equipment in the face based on the fusion of multi-sensor data and a position control method based on the neural network algorithm are elaborated, and the accurate detection and control of the position of the equipment group of the comprehensive mining face is achieved by the in-depth fusion of the position perception data and the position control data and iterative optimization; For the problem of controlling the speed of the equipment group of the comprehensive mining face, a force-electricity coupling method is proposed. For the speed control problem of the equipment group in the comprehensive mining face, the force-electricity coupling cutting load measurement method and the speed intelligent control method based on the artificial intelligence optimisation algorithm are proposed, which integrate the cutting load data and coal mining data, and use the artificial intelligence optimisation algorithm to make decisions on the optimal hauling speed, cutting speed and coal transporting speed, so as to realise the efficient and intelligent cutting control based on the speed matching of the equipment group. For the problem of cooperative control of equipment group in comprehensive mining face, the master-slave cooperative control method of equipment group based on artificial intelligence algorithm is elaborated, taking the position and speed control data of coal mining machine as the dominant, and the control data of scraper conveyor and hydraulic support as the follower, and solving the optimal cooperative control parameter of the displacement and speed of the equipment group by using the neural network algorithm of artificial intelligence, so as to realise the intelligent, efficient and safe operation of the equipment group. The five key technologies of ‘coal mining is data mining’ have been applied in coal mines, verifying the feasibility of the academic idea. The academic idea of ‘coal mining is data mining’ has laid an important theoretical foundation for breaking through the key technical problems of intelligent coal mining.
Data governance underpins the intelligent development of coal mines and ensures collaborative centralized control of mine systems. To tackle the issues of inadequate top-level design and methodological support in intelligent coal mine data governance, a methodological system has been developed. The methodological system comprises six key components: theoretical foundation, conceptual model, basic principles, processes and procedures, methods and tools, and evaluation criteria. It systematically clarifies the basis and principles for effectively realizing the goals of intelligent coal mine data governance, and provides the theoretical foundation and methodological support for the top-level design of intelligent coal mine data governance. Meanwhile, the implementation framework for intelligent coal mine data governance is developed with reference to relevant technical standards, which provides specific paths and management methods for the management and implementation of intelligent coal mine data governance. Furthermore, the technical architecture for intelligent coal mine data governance is designed based on the idea of layered architecture to provide technical methods and tools for the technical realization of intelligent coal mine data governance. The following study results have been obtained. ① The theoretical foundation of intelligent coal mine data governance is grounded in complex system theory, data strategy management theory, digital continuity theory, public governance theory, collaborative innovation theory, information lifecycle theory and PDCA cycle theory. ② The conceptual model of intelligent coal mine data governance consists of five core conceptual dimensions: governance philosophy, governance goals, governance subjects, governance objects, and governance processes and tools. It adheres to the principles of business orientation, collaborative governance, culture-driven, technology-enabled, process-embedded, and continuous improvement. ③ The implementation framework of intelligent coal mine data governance delineates the management processes and key procedures from the top down, encompassing four key links of the iterative cycle: coordination and planning, construction and operation, monitoring and evaluation, and improvement and optimization. ④ The technical architecture of the Data Lakehouse for intelligent coal mine describes the system structure and technology selection for the data governance platform. It offers technical methods and tools to facilitate the implementation of intelligent coal mine data governance, with the core focus on developing the five key layers of the data middle platform. ⑤ The data governance capability maturity model for intelligent coal mines provides an assessment criteria framework and capability improvement pathway. It encompasses three dimensions namely, the level of capability maturity, data governance capabilities, and data governance practices. The enhancement of data governance capabilities in intelligent coal mines progresses from project management to benchmarking, encompassing process, standardization, and quantitative management stages.
Adaptive cutting technology is crucial for enabling intelligent shearers, significantly improving mining efficiency, safety, and resource utilization. Therefore, a comprehensive review of adaptive cutting technology has been conducted, focusing on its technical principles and current applications. Based on core functions and technical objectives, adaptive cutting technology is categorized into four primary research areas: memory cutting, transparent geology, coal-rock identification, and adaptive control. Memory cutting enhance cutting paths by recording historical data, while transparent geology leverages integrated detection technologies to acquire real-time geological information. Coal-rock identification techniques are classified according to recognition principles: indirect methods based on physical parameters, direct methods relying on visual information, and wave-based detection methods such as ground-penetrating radar and ultrasound. Adaptive control automates the adjustment of shearer operating parameters. Collectively, these technologies advance the intelligence of coal mining machines from various perspectives. Nevertheless, due to geological complexities and challenging mining environments, existing technologies face limitations in adaptability and cost-effectiveness. Therefore, future development of adaptive cutting technology should focus on integrating memory cutting, transparent geology, and coal-rock identification technologies to enhance coal seam data acquisition. Implementing multi-sensor fusion technology to improve the accuracy and reliability of coal-rock identification. Developing intelligent decision-support systems based on big data analytics to optimize mining operations and researching multi-domain collaborative simulation control strategies to address technical challenges and improve system performance.
Existing methods for predicting hydraulic support loads in mine roadways usually assume a static spatio-temporal mining arrangement, which ignores the dynamic loads of the far-field surrounding rocks and affects the accuracy of rockburst prediction. In order to ensure safe mining, real-time and accurate predictive assessment of potential rockburst is necessary. In this paper, a Sparrow Search Algorithm-Random Forest (SSA–RF) prediction method based on digital twin and machine learning is proposed. By analyzing the interaction between the support system and the surrounding rock, a digital twin model of the two-column support is established, and the interaction mapping and synchronous feedback between the physical entity and its digital twin are realized based on data driving. By comparing and analyzing the calculated and real values of the attitude variables during the column lifting process of the two-column support, it is found that compared with the physical entity of the support, the digital twin model has an average error of 0.14° in angle and 6.15 mm in length, which is in line with the accuracy requirements. In addition, the Sparrow Search Algorithm was used to optimize the number of decision trees and node features in the Random Forest. Compared with using a single prediction model, the SSA–RF prediction modeling improves the convergence speed and optimization ability. The experimental results show that the SSA–RF method proposed in this paper performs optimally compared with prediction algorithms such as Long Short-Term Memory (LSTM), Random Forest (RF) and Support Vector Machine (SVM), and its prediction accuracy reaches 85.89% and 91.09% on the central support and end support data sets, respectively. In addition, it is found that the roof in the area of the central support is prone to fracture instability, which will destroy the vertical stress support conditions in the central area of the working face, thus leading to a larger range of load variations in the central support with a slightly lower prediction accuracy than that of the end support. The above results provide some theoretical reference for further research on the occurrence mechanism of rockburst in coal mine and accurate prediction of potential rockburst.
The fault monitoring of belt conveyors serves as a pivotal tool in preventing safety incidents, enhancing production efficiency, and facilitating the intelligent operation of equipment. This comprehensive study delves into the multi-sensor fault monitoring of belt conveyors utilizing Fiber Bragg Gratings (FBGs), examining aspects such as common fault analysis, the composition of integrated protection systems, the design and analysis of fiber-optic sensor arrays, and the design and material selection of core sensing elements.Firstly, to address the shortcomings of traditional monitoring methods, including the inability to quantify faults, inadequate real-time performance, and weak data fusion capabilities, an FBG-based integrated protection system for belt conveyors is proposed. This system underscores the cruciality of designing a fiber-optic sensor array as a fundamental prerequisite for system establishment.Secondly, building upon an analysis of the root causes and manifestations of common faults in belt conveyors, a series of fault monitoring sensors are devised, with FBG-based equal-strength cantilever beams serving as the core sensing elements. These sensors constitute the fiber-optic sensor array within the integrated protection system, enabling real-time and quantitative fault monitoring.Thirdly, theoretical analyses and Ansys finite element simulations are conducted to thoroughly investigate the dimensional design and material selection of FBG-based equal-strength cantilever beams. The influencing factors on sensitivity and accuracy are analyzed within the sensing model, guiding the determination of the structural dimensions of the sensing elements. Nylon 6 is selected as the optimal material for fabrication.Finally, experimental validation is performed to assess the structural effectiveness, sensitivity, and stability of the FBG-based equal-strength cantilever beams. In sensitivity tests, the sensing elements exhibit exceptional linear response characteristics, with a theoretical sensitivity of
Image monitoring is the main perception method for mine fire flames, but it is affected by mine light sources. The internal concavity can reduce the influence of camera installation position, shooting distance, and shooting angle, eliminate interference from mine light sources, and quickly identify and eliminate the front view and distorted images of non arc-shaped light sources such as rectangular light sources; However, for arc-shaped interference light sources such as circular light sources and quasi circular light sources, the computational complexity is large and the recognition time is long. Circularity can eliminate interference from circular light sources, but it is difficult to eliminate interference from non-circular light sources. Rectangularity can eliminate interference from rectangular light sources, but it is difficult to eliminate interference from non rectangular light sources. Due to factors such as camera installation position and angle, circular and rectangular light source images may become distorted and unable to present ideal regular shapes. Therefore, it is difficult to eliminate the interference of mine light sources using circularity and rectangularity algorithms. It reveals that there are multiple depression areas on the boundary of the flame image, with a relatively large total depression area. However, there are no depression areas on the boundary of actual mine light source images such as circular lights, rectangular lights, and square lights. Propose a method based on the recognition of depression degree in images of external mine fires, calculating the ratio of the total concavity area of the target image boundary to the actual area of the target image (i.e. image depression degree). Based on the larger depression degree value in flame images and the smaller depression degree value in mine light source images, distinguish between mine light sources and flames. The depression degree method proposed in this article is not affected by the distance and image size between the camera and the detection target, the installation position and angle of the camera shooting the detection target, the shape of the mine light source, etc. It has strong adaptability and high recognition accuracy. The average difference in depression degree between the mine interference light source image and the flame image calculated by the depression degree recognition method has the largest absolute value, small fluctuations, and the best discrimination. The average difference in the internal concavity between the mine interference light source image and the flame image calculated by the internal concavity recognition method is relatively large in absolute value, with small fluctuations and good discrimination. The rectangular degree recognition method calculates that the absolute value of the average difference between the rectangular degree of the mine interference light source and the flame image is in the middle, with large fluctuations and good discrimination. The roundness recognition method calculates the minimum absolute value of the average difference between the roundness of the mine interference light source and the flame image, with the largest fluctuation and the worst discrimination. Experimental studies have shown that the accuracy of recognizing fire flame images based on depression degree is 98.2%, and the recall rate is 98.4%, the best accuracy and recall; The accuracy of identifying fire flame images based on the internal concavity is 92.8%, and the recall rate is 92.4%, the better accuracy and recall; The accuracy of rectangularity recognition is 86.5%, and the recall rate is 86.5%, the worse accuracy and recall; The accuracy of circularity recognition is only 35.9%, and the recall rate is 31.9%, the worst accuracy and recall.
Existing coal gangue sorting robots face challenges in mispicking, empty grabs, and collisions during the sorting process. These issues primarily stem from the phenomena of slippage and deviation of coal gangue during belt transportation, making it difficult to accurately acquire real-time positional information of the gangue using belt speed-based tracking methods. This leads to significant errors in the robotic arm’s grabbing actions, adversely affecting the sorting efficiency. To address this issue, a vision-based real-time guidance method for coal gangue tracking is proposed. This method involves capturing the real-time positional information of the coal gangue through cameras, guiding the robotic arm to adjust its actions for tracking and grabbing the gangue. Initially, the vision recognition module acquires the target's initial position and tracking template, with the control system allocating strategies to assign the gangue to the respective robotic arm for grabbing. Once the target gangue enters the robotic arm's grabbing work area, a monocular target tracking model, built on Siamese networks, captures the real-time positional information of the gangue, enabling the arm to adjust its movements dynamically to complete the grab. Subsequently, visual tracking experiments on coal gangue at different belt speeds were conducted, and a coal gangue sorting robot simulation system was developed to perform trajectory planning simulations under various conditions of slippage and deviation. The simulation experiment results demonstrate that the constructed coal gangue tracking model achieves a tracking accuracy of 96.9% and a tracking speed of 39FPS, meeting the needs for real-time guidance. When facing varying degrees of slippage and deviation, the grabbing error of the robotic arm, guided by real-time vision, is reduced to within 1 mm. Compared to the belt speed-based tracking method, this approach effectively eliminates cumulative errors caused by belt slippage and deviation during transportation, enhances the system’s real-time responsiveness, and further improves the efficiency of coal gangue sorting.
China’s coal production is dominated by underground mining. With increasing mining depth, there is an observed rise in the proportion of saline mine water emissions. Saline mine water is mine water with a total salt content exceeding 1 000 mg/L. Based on the distinct ionic composition, China’s saline mine water is categorized into five types: chloride type, sulfate type, carbonate type, chloride-sulfate type, and composite type. The predominant types are chloride type, sulfate type, and chloride-sulfate type. In light of the problem of mine water with a total salt content that exceeds the prescribed standard, the state and local governments have introduced the requirement of salt discharge limitation, and have conducted research and practical application in treating saline mine water. The development history and research status of salt mine water treatment technology internationally are described, and the advantages and disadvantages of the pretreatment process, membrane concentration process, and evaporation crystallization process are analyzed, as well as the applicable conditions. The whole process treatment technology for salt-containing mine water involves a combination of pretreatment, multi-stage membrane concentration, and salt crystallization. The discussion encompasses the technical characteristics, scope of application, and status of high-efficiency reverse osmosis (HERO) and moderate step-by-step synergistic treatment technology (SPMS2) in the context of differing membrane concentration pre-treatment processes. Similarly, the technical characteristics, scope of application, and status of evaporation salt crystallization and nanofiltration salt crystallization technologies are discussed concerning different salt crystallization processes. Concerning the challenges currently faced by membrane concentration and evaporation crystallization technology, and the future development direction, the following proposals are put forward: the ongoing advancement of high-efficiency short-flow membrane concentration and low-carbon evaporation crystallization processing technology and equipment; the sustained investigation of the conversion of low-value by-product salts and the extraction of high-value components; actively explore the joint treatment mode of low-grade heat source, geothermal or photovoltaic power and salt-containing mine water; proactively investigate the regional centralized treatment mode of salt-containing mine water; and explore the technical, policy and economic feasibility of off-grid new energy applications, and study naturally enhanced evaporation and concentration technologies.
Ecological restoration in mining area is a focal point and challenge in the terrestrial ecological conservation and restoration in China. Currently, ecological restoration in mining areas emphasis on natural recovery, transitioning towards a more systematic, integrated, and sustainable solution. This study synthesizes existing literature, conducts comparative analyses, and summarizes key findings to propose a holistic approach. The proposed technical framework spans the overall lifecycle of ecological restoration, covering key stages such as protection and prevention, reclamation and restoration, management and maintenance, monitoring and evaluation, and adaptive management. Initially, the integration of NbS concepts in the stages of ecological protection and prevention involves strategies such as avoidance measures, protection of crucial species, and the utilization of species collection to mitigate the ecological damage caused by mining. This integrated approach serves to enhance the self-recovery capacity of ecosystem and reduce costs. Subsequently, incorporating NbS principles into specific restoration measures, such as landform reshaping, soil reconstruction, vegetation restoration, and landscape rebuilding, stimulate the self-recovery of mine ecological systems of mimicking natural processes. This method provides scientifically sound, efficient, and sustainable restoration solutions. Moreover, incorporating NbS principles into the management and maintenance of mine ecological restoration focuses on the preservation of infrastructure, soil, vegetation, and the maintenance of ecosystem functionality. These practices align with contemporary mainstream approaches to ecosystem restoration. Lastly, conducting the overall life cycle monitoring and evaluation including the before, during and after mining processes, and the adaptive management can be applied through comparative analysis. Overall, the framework and technical pathways designed in this study provide valuable insights for advancing ecological restoration practices in the new era, ultimately contributing to the holistic protection and sustainable management of restored ecosystems in mining areas throughout its overall life cycle.