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In this paper, it is pointed out that there are several main problems in the construction of intelligent open-pit mines in China at this stage, such as independent systems, mainly relying on manual control, passive implementation of disaster monitoring and lack of intelligent analysis. Moreover, this paper explores the connotation of intelligent open-pit mines and defines the intelligent open-pit mines as a large intelligent driven system consisting of Internet of everything and platform integration. The underlying platform of intelligent open-pit mines based on industrial Internet of things cloud operating system is proposed. Real-time data is obtained by advanced programmable remote utility server via Modbus/OPC/PPI/MPI and other industrial protocols. Off-line data can be entered manually according to the needs of field work. These data can be connected to the existing ERP or manufacturing execution system of open pit mining enterprises to realize the seamless connection of external data. Based on the industrial Internet of Things cloud operating system MixIOT as the platform, raster database, offline database, statistical database, report database, etc. are established according to different data sources to realize routing, exchange and storage of all kinds of data in open pit mines. At the same time, industrial data analysis service system is used to analyze the operation of open-pit mine production equipment. The three key technologies of the underlying platform of intelligent open-pit mines are data acquisition technology, data analysis service technology and application display technology.

In order to classify the types of hydraulically fractured coal and rock seam combinations, the No.3 coal seam in Yuwu wellfield of Lu’an Mining area are taken as the research object in this paper, and the lithology and mechanical characteristics of the roof was obtained by logging interpretation and mechanical testing. The coal structure of coal seam section is identified by the combination of core well and logging. The stress state was obtained according to the method of calculated stress of hydraulic fracturing stress and density logging. On this basis, types of hydraulically fractured coal and rock seam combinations were classified, and the hydraulic fracturing measures for different combination types are proposed. The results show that the types of hydraulically fractured coal and rock combinations in the study area can be classified into seven types: hard rock and hard coal, soft rock and hard coal, hard rock and soft coal, soft rock and soft coal combination of transitional type and tensile type. When hard rock and hard coal was combined, long fractures and effectively supported fractures can be created by adopting large displacement, multiple fluid volume, low or medium sand ratio and step by step sand addition. When soft rock and hard coal was combined, avoid shooting part of the coal seam to prevent fracturing fluid entering the interface between coal seams and soft rocks, which can ensure the fracturing effect. Roof hydraulic fracturing is recommended for the stretching combination of hard rock and soft coal. In the transitional hydraulic fracturing of hard rock and soft coal, the fracturing parameters are optimized according to the difference between horizontal stress and vertical stress. When soft rock and soft coal are combined, hydraulic fracturing is not recommended for reconstruction.

Aiming at the problem of low accuracy of traditional channel estimation algorithms in the harsh environment of underground coal mines, this paper proposes an improved Super Resolution Convdutional Network (SRCNN) for channel estimation. In the improved SRCNN model, the estimated value at the pilot frequency is used as input, and the improved SRCNN model replaces the interpolation process in the traditional channel estimation algorithm to reduce the complexity, and the attention mechanism ECA module is added to improve the learning of channel features to achieve more accurate channel estimation for the underground coal mine environment. Simulation results show that the channel estimation algorithm of the improved SRCNN model outperforms the traditional channel estimation algorithm and improves the estimation accuracy by one order of magnitude compared with the channel estimation of the SRCNN model.

The coal industry urgently needs real-time access to comprehensive information on coal quality and quantity for its digital transformation. Based on analyzing the industrial application requirements for comprehensive analysis of coal quality and quantity, this paper focuses on the technical principles, research status, and industrial application of spectroscopic techniques represented by laser-induced breakdown spectroscopy (LIBS) and multispectral fusion with other spectroscopic techniques. It also discusses the artificial intelligence-based coal quality and quantity detection methods represented by image analysis. Then, based on the industrial application scenarios of different technologies, we need to analyze the technical limitations of real-time coal quality and quantity online detection technology in industrial applications. These limitations include detection accuracy issue based on technical principles, equipment stability issue caused by complex environmental factors, algorithm analysis issue based on large-scale data processing, technical applicability, and flexibility issue in the entire coal industry chain, respectively. Finally, four development suggestions for future comprehensive analysis and online detection technology of coal quality and quantity were proposed, they are research on coal quality online detection technology considering geological conditions, research on industrial-scale multispectral fusion technology, research on comprehensive analysis of coal quality and quantity using spectroscopy and image analysis techniques and in-depth research on the application of intelligent technologies in real-time coal quality and quantity detection, respectively. Coal quality online detection is a complex field that involves multiple disciplines and specialized knowledge. It relies on interdisciplinary scientific and technological fields such as coal petrography, spectroscopy, instrument engineering, data processing, pattern recognition, artificial intelligence, and machine learning. Establishing industrial application scenario-coal quality and coal quantity parameters-actual application guidance databases is an important direction for achieving intelligent coal quality and coal quantity online detection and obtaining comprehensive coal quality and coal quantity information.

The goal of “carbon peak and carbon neutrality” is China’s responsibility as a major country to maintain global ecological security, and it is also an important way to achieve high-quality development and ecological civilization construction. CO2 emission reduction is imperative.As a result of the energy resource endowment pattern of “rich in coal, poor in oil and less gas”, the main energy in China is still coal with high carbon emission intensity. Coal is an important energy and raw material for high energy-consuming industries such as electric power, iron and steel and coal chemical industry. it plays an important role in the process of achieving the goal of “double carbon”. The coal industry achieves carbon peak through low-carbon transformation, which is the inherent requirement of the high-quality development of coal industry. It is also an important starting point for the implementation of the national “double carbon” strategic goal. Compared with the traditional natural mineralization raw materials, coal-based solid waste mineralization and storage CO2 has the advantages of rich raw materials, friendly products, low energy consumption and rapid reaction. At the same time, it can produce high value-added products for chemical industry, construction and other fields. The characteristics of main coal-based solid waste coal gangue, fly ash, desulphurization gypsum, gasification slag and furnace bottom slag in China are introduced, the main CO2 emission sources and production in China are analyzed, and the in-situ and ex-situ CO2 mineralization technologies according to different mineralization and storage locations and direct and indirect carbonation technologies according to mineralization mechanism are reviewed. The research progress of CO2 mineralization and storage technology using coal-based solid waste as raw material is reviewed, and it is found that this technology has harsh reaction conditions, high cost, small treatment scale, and the research is still in the laboratory stage. This paper briefly describes the mineralization and storage technology of CO2 with coal-based solid waste as carrier and goaf as storage source, which mainly includes two technologies: construction of functional filling body and preparation of negative carbon filling material. The existing problems and future research direction of coal-based solid waste mineralization and storage of CO2 are analyzed. For the CO2 mineralization technology with coal-based solid waste as raw material, the technological process should be optimized, the reaction cost should be reduced, and the research on industrialization promotion should be further strengthened. aiming at the CO2 mineralization and storage technology with coal-based solid waste as carrier and goaf as storage source, the research on deep mineralization mechanism, storage risk assessment and long-term stability should be strengthened in the future, so as to improve the storage scale and long-term stability of CO2. On this basis, the slurry filling material is prepared from coal-based solid waste, with water as carrier, pump as power and pipeline as channel, the filling material and CO2 are transported to the goaf for mineralization reaction, and combined with microbial induced calcium carbonate precipitation (MICP) technology, the mining fissures in rock mass are closed to realize CO2 mineralization and storage.

Intelligent equipment is an inevitable trend for the high-quality development of the coal industry, With the construction of super high mining height and super long working face in coal mine, scraper conveyor has been developing towards heavy and long distance, and permanent magnet direct drive has gradually replaced “asynchronous motor + reducer” to become the main driving mode of scraper conveyor. However, the traditional dual-drive scraper conveyor has the problems of high shutdown rate, uneven distribution of coal flow and large energy consumption, poor tracking performance, especially the fluctuation of the chain tension under long transport distance causes the surge of the driving motor circuit, which has become the main problem that limits the intelligent development of scraper conveyor in our country. According to the main problems and development needs of scraper conveyor, this paper puts forward a new mode of scraper conveyor with multiple permanent magnet motors in series “drive - drive”, and expounds the research status of key technologies involved in the research field of scraper conveyor with multiple permanent magnet motors in series. Including the scraper conveyor fault diagnosis and state recognition technology, multi-motor series drive “mechanical-electrical” coupling dynamic characteristics, multi-permanent magnet motor synchronous control technology, multi-agent adaptive cooperative control, for the design and development of multi-drive scraper conveyor has certain adaptability and reference. In view of the difficulties faced by the research of multiple permanent magnet motor series drive system of scraper conveyor, the system is divided into four key science and technology: ① new configuration design of multi-drive scraper conveyor; ② nonlinear mechano-electrical coupling dynamics modeling of multi-drive scraper conveyor; ③ chain tension pulsation and active control of multi-drive scraper conveyor; ④ active fault tolerance and adaptive cooperative control of series drive scraper conveyor. From the structural design and optimization, the whole machine operation and maintenance control to achieve scraper conveyor multiple permanent magnet motor series drive system technology research, improve the scraper conveyor intelligent level, promote the level and development of high-end equipment of coal machinery.

Due to high-intensity mining and complex geological conditions, frequent occurrence of rock burst disasters in deep coal mines in China is posing serious threats to mine safety and efficiency. The insufficient locating accuracy of the seismic monitoring system in burst-prone coal mines is still presented, which leads to difficulties in accurately identifying and controlling coal burst hazards. To precisely characterize spatial evolution of seismic activities and reduce the impact of location error on the seismic pre-warning, this paper used the current seismic networks in burst-prone coal mines to conduct forward modeling experiments to explore the distribution characteristics of source location error vectors in the mining field. A new method for characterizing seismic fracture connectivity that considers location accuracy impacts was proposed and applied for coal burst pre-warning in a longwall face. The results show that significant vectorial differences of seismic source location accuracy at different area of the mining field is a key factor in false identifying coal burst risks. The proposed Fracture-connectivity-probability Index (\begin{document}$ F{_{{\mathrm{sum}}}} $\end{document}) characterizes the rupture scale by using the near-field radius that relates to the seismic energy level, which considers the locating error impacts on fracture connectivity between seismic sources at different distances. \begin{document}$ F{_{{\mathrm{sum}}}} $\end{document} can restore the distribution law of the fracture extension and connectivity probabilities of the coal-rock mass in the greatest extent, and it also corresponds well to the coal burst risks. \begin{document}$ F{_{{\mathrm{sum}}}} $\end{document} can balance forecast accuracy and recall rate and have better correlation with coal burst, which can be an ideal indicator for periodical coal burst risk assessment. The outcome of this research can provide references for evaluating the monitoring capability of seismic networks and improving the ability and efficiency of coal burst pre-warning and prevention.

In response to the technical challenges of supporting tunnels in loose and fragmented surrounding rock with poor anchorage, strong dynamic pressure, and strong structural stress influences, extensive on-site surveys were conducted, and several typical problems of large deformation in coal mine tunnel surrounding rock and difficulty in rock control were summarized and analyzed. Based on the analysis of existing support technologies and theoretical foundations, a concept and method for the rapid support technology of reconstructing high-strength load-bearing structures were proposed. Taking the 11205 down-hill transport tunnel at Longbao Coal Mine in Guizhou as an engineering background, the causes of deformation and failure were analyzed. A combined support method of displacement and unloading for fragmented surrounding rock was designed in practice. The design plan and optimal parameter calculations for the roadside backfill wall were carried out, and a mechanical model for the load-bearing capacity of the roadside backfill wall was theoretically established. Its load-bearing strength was analyzed to determine the strength of the wall and its suitability and effectiveness with the surrounding rock of the tunnel. By integrating the FLAC3D numerical simulation software and the Python scripting language, the moth-flame optimization algorithm was applied to determine the optimal displacement parameters for the fragmented rock tunnel (wall thickness and unloading zone width). A new material for high-strength, high-toughness backfill support was developed. By displacing and reconstructing the weak wall body, the tunnel roof, backfill, and floor were reconstituted into an integral load-bearing structure. Industrial-scale trial results underground showed that after reconstructing the weak rock body of the tunnel, the new structure consisting of the roof, backfill, and floor fully utilized the surrounding rock’s own load-bearing capacity and resistance to deformation. The rock deformation stabilized, the convergence rate was generally less than 0.2 mm/d, with no significant deformation, and the results of the numerical simulation calculations were consistent with the engineering practice monitoring, indicating that the roadside backfill displacement support scheme has a good effect on controlling tunnels in loose and fragmented surrounding rock. This can provide a theoretical basis for the support and strength parameters of roadside backfill. Finally, the paper looked forward to deeper research into the technology of rapid support for reconstructed load-bearing structures.

Underground coal gasification is currently the highest-temperature (over 1200 ℃) unconventional development method for fossil energy. Underground gasification of coal in the medium-deep (refer to the depth of 800～1500 m in this paper) has obvious advantages in improving the gasification pressure and reducing the geological safety risks. Scientific prediction of safe width of gasification cavity is important to ensure stable gasification operation. Since the method of calculating the safe width of gasification cavity based on Controlled Retreat Injection Point (CRIP) process has not yet been established, targeted research is needed to ensure the smooth implementation of field tests. Once the top plate of the gasification cavity is “exposed” to high temperature behind the gasification cavity. The generation position of thermal stresses inside the rock and the influence law of differences in the thermal expansion coefficient of particles and matrix on the magnitude of thermal stresses were studied by numerical simulation under compressive stress constraints. the thermal damage mechanism of rock under high temperature was clarified combined with the scanning electron microscope results of rock after high temperature treatment. According to the characteristics of CRIP gasification process, a thin plate model of gasification cavity roof considering the influence of high temperature was established, and a method for calculating the safe width of the gasification cavity was proposed in combination with the theory of “key layer”. The study revealed that, rock thermal damage was caused by the interaction and synergy of rock physicochemical reactions and thermal stress, and the rock undergone irregular deformation at high temperatures. Microstructural changes of rock caused by the thermal damage were the fundamental cause of changes in rock mechanical and physical properties. The maximum tensile thermal stress in rock occurred at the grain interfaces or in grains with small coefficient of thermal expansion. The maximum tensile thermal stress increased rapidly with decreasing the thermal expansion coefficient of the grain when the ratio of the thermal expansion coefficient of the grain to that of the matrix is in the range of [0.01−1). The microcracks of mudstone was developed when heated to 200 ℃, the crack development was more obvious when heated to 400 ℃, which mainly along the edge of the particles rupture. The number of cracks was increased and the size was larger when heated to 600−800 ℃. The larger cracks and numerous pores were formed when heated to 1000 ℃. The crack connectivity increased significantly at 1200 °C, and the stomatal development was larger. Due to the effect of high temperature, the step constant for the thin plate model is no longer a constant, and specific values need to be determined based on the extent of thermal damage to the roof of gasification cavity and the location of the hard rock layer on the top plate. The safe width of gasification cavity was affected by temperature. In the study, the calculated safe widths of sandstone roof at 35 and 1000 °C were 34.3 m and 14.1 m, respectively, with a difference of 58.9%. while the safe widths at 35 and 1000 °C were 16.7 m and 15.9 m, respectively, with a 4.8% difference. Lastly, a method of determining the longitudinal target area of coal seam was proposed from the perspective of reducing the risk of roof collapse and improving gasification control. When the coal seam thickness exceeded half of the gasification cavity safe width, it was suggested to design the longitudinal target area of horizontal well at a location not more than half of the safe width of gasification cavity from the top of the coal.

This is an article in the field of earth sciences. To reveal the mineral chemistry characteristics and metamorphic temperature of garnet in the Liwu Group due to core of Jianglang dome, the major, trace and rare earth elements of garnet were analyzed at different locations in this paper. The results show that the major-element composition of garnet in schist from the Jianglang dome is mainly Alm. ICP-MS (average content 85.82%) and LA-ICP-MS (average content 83.51%) is basically consistent within the error range of the Alm content obtained.The total content of rare earth elements (REE) is high, and show obvious LREE-depleted and HREE-enriched left-declined REE distribution patterns, with unobvious Eu anomalies and negative Ce anomalies, Enriched in large ionic strength elements (U, Ta, Hf)and depleted high field lithophile elements (K, Sr, Ba). In addition, the formation temperature of garnet in schist from the Jianglang dome is 512～583 ℃, and the formed metamorphic pressure is relatively low. It is a negative correlation between the metamorphic temperature and the distance to the Xinhuoshan granite. In conclusion, the Jianglang dome experienced “Barrovian-type” metamorphism of high greenschist facies.

This is an article in the field of earth sciences. Jiulong area is the most concentrated area of Yanshanian granite found in western Sichuan, including Tiechanghe, Qiaopengzi-Landiao and Xinhuoshangranite. In this paper, LA-ICP-MS zircon U-Pb dating were carried out to determine the formation age of the granite， and its temporal-spatial relationship with the surrounding granites, providing a basis for the comparative study of Liwu copper deposit in the southern margin of Songpan-Ganzi block. The results show thatthe diagenetic age of Huajiaoping granite is (163.1±1.4) Ma, andit underwent magmatic or tectonic thermal events at (146±3) Ma, which is consistent withthe geological events ofTiechanghe, Xinhuoshan and Luomogranite. The magma temperature of Huajiaoping granite is 592～727 ℃ (average temperature 648 ℃), which is significantly lower than that of Qiaopengzi granite (766～804 ℃). Combined with the regional geological background, about 170 ～ 140 Ma, the lithosphere in the southern margin of Songpan Ganzi block is in the extension stage. The granite magma activity dominated in the early stage (163 Ma) by Huajiaoping granite, and in the late stage (146 Ma) by magmatism or tectonic thermal events. This discovery enriched the Yanshannian granitic magmatic thermal events in Jiulong area.

This is an article in the field of earth sciences. The newly discovered Maoping graphite deposit is a super-large crystalline graphite deposit that is located in the middle-northern section of the Kang-Dian fault-uplift belt on the western margin of the Upper Yangtze paleo-continent, and the research on the source of mineralization and its mineralization age is relatively weak. The orebodies occur in the epimetamorphic rocks of Mesoproterozoic Tianbaoshan Formation. In this paper, the geochemical characteristics of major ores, trace amounts and rare earth elements were mainly studied. The results show that the original rock of the ore-bearing rock layer is parametamorphic rock, a set of carbonaceous quartz-bearing siltstone, which is deposited in an oxygen-deficient environment. The characteristics of trace elements indicate that the original rock of the ore body is formed by the deposition of offshore terrigenous clasts. The ores show sedimentary characteristics of coastal tidal flat facies, with an average ΣREE of 158 g/t, average δ Ce value of 0.63 (weak negative anomaly), and an average δ Eu value of 0.69 (negative abnormaly). The graphite ore body has a δ13C value of -28.35‰～-29.08‰, with an average of -28.59‰, indicating that the mineralized carbon is dominated by organic carbon. The LA-MC-ICP-MS Zircon U-Pb of amphibole zircon from Xijie hornblende diorite Zircon is (823.4±3.6) Ma, which is later than the formation era of volcanic rocks of the Tianbaoshan Formation (954 Ma), representing the time of superposition metamorphism of graphite. In summary,the genetic type of the ore deposit is sedimentary- metamorphism and its metamorphism may include the regional dynamic metamorphism of Jinning period that is superimposed by contact metamorphism.

This is an article in the field of mineral processing engineering. Barium slag is toxic solid waste, and a large amount of barium slag is piled up to seriously harm the environment and cause huge waste of national land resources. Acid-dissolving barium in acid leaching barium residue is one of the best ways to dispose of barium residue and recover barium. The paper adopts the flotation process to recover the barium sulfate in the acid leaching tailings of the enriched barium slag, in order to realize the comprehensive recovery of barium resources in the barium slag. The experimental research of the flotation recovery of barium residue acid leaching residue shows that. Under the condition that the amount of sodium carbonate is 2000 g/t, the amount of sodium silicate is 500 g/t and the amount of sodium oleate is 3000 g/t, through the flotation closed-circuit process of one roughing, four beneficiation, and two sweeping. Obtained the flotation index of 85.38% barite concentrate grade and 69.35% recovery rate. Concentrate products meet the barite standards used in the industrial production of barium carbonate.

This is an article in the field of mineral processing engineering. Some unavoidable ions commonly present in the slurry solution have an important influence on the flotation separation of lead-zinc sulfide ore. The unavoidable ions in the slurry mainly come from the water used in the processing plant, the dissolution of minerals, the dissociation of activators or depressants, and the primary ions introduced by the release of fluid inclusions and the secondary ions introduced during the grinding process. This article summarizes and analyzes the effects on the flotation separation of lead-zinc sulfide ore which is caused by the primary ions introduced in the slurry and the secondary inevitable ions introduced in the grinding system. It is found that both primary ions and secondary ions have obvious effects on the flotation behavior of lead-zinc sulfide ore. And many scholars have done a lot of research on this phenomenon. In this paper, a great breakthrough has been made through the adjustment and control of reagents and changes in the grinding environment. At the same time, this article provides important research ideas for follow-up researchers. The focus of this article is how to integrate the previous research results with the field process significantly, how to eliminate inevitable ions from the source without affecting the industrial economy, The important direction of future research is still how to reduce the influence of inevitable ions on the flotation index from the field process.

This is an article in the field of earth sciences. Xidamingshan polymetallic ore concentration area is critical mineral prospecting district in Guangxi. With the promotion of the large-scale mineral breakthrough work, the Xidamingshan mineral exploration, the Nongtun large-scale Pb-Zn deposit has been newly discovered. However, the understanding of the metallogenic characteristics of the deposit, especially the genesis of the deposit, is still at the superficial stage. Based on detailed field geological investigations and previous work, this paper systematically summarizes the regional metallogenic geological background, mining area and geological characteristics, and analyzes the genesis of the Nongtun lead-zinc deposit to find out the metallogenic mechanism. The study shows the Nongtun Pb-Zn deposit is related-magmatic hydrothermal deposit, the ore-forming fluids originated from magmatic, and later mixed with meteoric water. The fluids extracted Pb and Zn ore-forming elements from the strata during long-distance transport, and combined with S of magmatic fluids to synthesize [HS]-ligand that converged in the fracture zone and transported to the shallow part, thus forming Pb-Zn ore vein. The above research results have established the metallogenic model of the Nongtun Pb-Zn deposit, which provides a good guidance for prospecting prediction and exploration.

This is an article in the field of earth sciences. Magmatic rocks of the Gondwana Belt are one of the most popular problems in basic geological research on the Xizang-Qinghai Plateau. In this paper, we analyze the physical origin and regional tectonic properties of the Gachatai granite using LA-ICP-MS zircon U-Pb dating method, combined with the geochemical characteristics of the rocks and various graphical methods. The rocks are characterized by high alkali (average Na2O+K2O content of 6.26%), potassium (K2O/Na2O=1.03), low TiO2 (average 0.50%) and quasi-aluminous (aluminum saturation index A/CNK=0.933～1.033, average 0.991) high potassium-calcium-alkaline rock system. Rare earth elements show negative anomalies at Eu, which is the Eu-deficient type, and Ce has weak negative anomalies; trace elements show enrichment of large ion-parental elements Rb, Th, Nd, La and K; high field strength elements Nb, Ba, U, Ta, Ce, Sm and Ti are deficient; reflecting the mixed crust-mantle type of magma origin and the presence of subduction oceanic crustal melting. The zircon LA-ICP-MS U-Pb isotopic age is （345.3±1.8） Ma, and its formation age is Early Carboniferous. The analysis of the regional geological data suggests that this magmatic event is a product of the formation of the northern part of the eastern Gondwana continent after the breakup of the Rodinia supercontinent. The project points go to I-type granite, the discriminant diagrams indicate it’s formed from continental island arc, going through time before plate collision to co-collisional orogenic movement, which indicates a long period time of magmatic evolution; the rock geochemical characteristics show the environment of magmatic evolution changed from the start of island arc(primary island arc)-development(early stage island arc)-maturement(full-grown island arc).

This is an article in the field of earth sciences. Based on the 1∶25000 trench soil geochemical survey carried out in the Yongxi gold polymetallic mining area in Danba County, this paper reveals the element geochemical characteristics and anomaly distribution laws represented by gold, silver, arsenic and antimony in this area, finds a number of valuable geochemical comprehensive anomalies, analyzes the prospecting potential of geochemical anomaly areas, further narrows the prospecting scope, and delimits a prospecting target area. The engineering verification of the target area has achieved good prospecting results, which proves that the trench soil geochemical survey method is effective in the geological exploration work in this area, and provides a scientific basis for further geological work.

This is an article in the field of metallurgical engineering. A copper cobalt ore Congo is an oxide ore with Cu 3.43% and Co 0.42% respectively. In this paper, the five stage cycle leaching process of leaching solution was used for the copper and cobalt leaching. The optimum conditions were as follows: the amount of sulfuric acid was 7.4% of the ore mass, the amount of sodium sulfite was 1.68 times of the theoretical amount, the grinding particle size of -74 μm accounts for 75%, leaching temperature was 45 ℃, the single-stage leaching time was 4 hours, and the liquid-solid volume mass ratio was between 2/1 and 3/1, the results showed that the leaching rate of copper and cobalt were 96.85% and 95.67% respectively. According to this leaching process, the amount of sulfuric acid was reduced by 6 kg/t compared with the primary leaching, and the total solution amount in the leaching process was reduced by about 1/4, which made the amount of subsequent cobalt precipitation and copper extraction solution was reduced.

In order to prevent major acid drainage pollution accidents, this study aims to improve the accuracy of acid production potential evaluation of mine rocks in the prediction of acid drainage. Specifically, this paper introduced existing calculation methods of acid-producing potential, and then determined the acid-producing mineral contents in some sulfur minerals and coal gangue samples by three-step sequential extraction method, which is then compared with the traditional method of calculating the maximum acid-producing potential by measuring total sulfur. Results show that: 1) the acid-producing potential of coal gangue is dependent on the mass percentage content of each acid-producing sulfur and the corresponding unit acid value; 2) except for sample SC, the acid-producing potential calculated by acid-producing sulfur content is lower than(with different degrees) the acid-producing potential predicted by total sulfur. The sulfur in the sample SC is mainly arsenopyrite sulfur, which has a higher acid value per unit than pyrite sulfur, resulting in a higher acid potential calculated by SC sample than predicted by total sulfur; 3) the three-step sequential extraction is suitable for samples with iron and copper sulfides as the main sulfur minerals; 4) when other sulfide components increase and blank samples are unevenly mixed, the results will be disturbed to some extent. This research provides evidences to justify the evaluation of accurate acid production potential of coal gangue in mining area.

The highly-efficient treatment of coal mine water with low energy consumption contributes to much safer and more efficient coal mining. At present, mine water processing at underground is still limited for its small treatment water yield, large land coverage and high operation cost in ground treatment, high drainage costs when mine water is discharged into the surface water system. In this light, this study puts forward the "deep ground-underground-surface ground" linkage system for mine water treatment and utilization. The treated mine water is partially used for mining production and residential usage, while the rest is subject to deep reinjection or drainage. This paper first introduces the operational mechanism behind this system, and then evaluates its validity in terms of water quality, water quantity, hydrogeology, underground structure, and feasibility of recharge engineering. This study then reviews existing mine water treatment methods for varying water qualities and the "underground-surface" joint treatment system; Also, a summary is drawn regarding the selection of aquifer for reinjection purposes, reinjection construction operations, reinjection tests, simulation of reinjection water quality, and analysis of reinjection safety.

This study attempts to enhance the separation efficiency of dense media cyclone for raw coal feed with difficult-to-cleaning and large high-density component content. Specifically, this paper 1) designed a novel heavy media cyclone model device, 2) established a mathematical model of sedimentation separation of particles in the centrifugal rotating flow field, 3) investigated the separation characteristics of the new dense media cyclone by combining experimental research and theoretical analysis, which revealed the separation variation patterns of raw coal difficult to select with high content heavy density components under different process parameters, 4) explored the factors affecting the dynamic stability of the working suspension in the flow field of the new heavy media cyclone and the discharge and transportation mechanism of heavy products. Results show that when the new dense media cyclone separates raw coal with high content of heavy density components, underflow heavy products exhibit stronger discharge capacity and higher processing capacity, while the centrifugal swirl field shows smaller density gradient distribution of suspension, more uniform density distribution, lower value of the difference between the underflow and the overflow density, as well as stronger stability of the suspension in the flow field. The feeding pressure is directly correlated with the dynamic stability of the suspension, separation accuracy and the discharge efficiency of heavy products. With increasing feeding pressure, the suspension discharged from the underflow and overflow port shows increased density difference, reduced possible deviation E value, improved separation accuracy and elevated amount of heavy product discharged. When the feeding pressure is 25 kPa, the actual separation density is 1.666 g/cm3, the possible deviation E value is 0.09 g/cm3, and the yield of heavy products is 75.23%, which provides new insights into the separation of raw coal with high content, heavy density components.

In order to reveal the seepage evolution law of high-pressure water injection and improve the effect of water injection and dust suppression in coal, based on triaxial compression and coal mining practices, this paper obtains the matching relationship between coal deformation and pore water pressure through coal-rock permeability test. The user-defined function module is used to compile the relationship into Fluent to simulate the fluid pressure field, velocity field and water distribution in the process of drilling water injection, and analyze the wetting range and seepage velocity in coal around the radial direction of drilling hole under different water injection pressures. The results show that the seepage field pressure increases with the increase of pore water pressure, and the rate of pressure change gradually decreases with the increase of time, and the variation of seepage field velocity shows a similar change law. With the continuous increase of pore water pressure, the porosity of coal increases, and the water content of coal increases gradually, and the distribution range is gradually expanded from around the borehole to both sides. The wetting process around the borehole of coal seam increases rapidly and then decreases slowly to reach a stable state.

With the increasing of mining depth, the problem of gas outburst becomes increasingly prominent. How to quickly and safely carry out rock cross-cut coal uncovering is an important goal to ensure the safety of coal mine production. In this paper, based on the graphical analysis method, the relevant literatures in the recent 30 years in the database of CNKI are selected as samples to analyze the research hotspots in the field of local outburst prevention of the rock cross-cut coal uncovering. After analyzing the research progress and shortcomings of the measures to outburst prevention, it is found that the low temperature freezing reduce the energy storage of coal seam and improve the strength of coal mass. However, coal strength is crucial to prevent gas disasters, because the occurrence of coal and gas outburst accidents is caused by the energy storage instability of coal seam breaking through the resistance of coal mass. Based on the technical problems existing in the field of local outburst prevention and the shortcomings of artificial freezing method，combined with intelligent technology, an intelligent integration measure of “drilling, pumping and injection” is proposed. Real-time monitoring and early warning are carried out through signal base stations and local area networks to achieve accurate outburst prevention. By combining the establishment of multi-physics coupling model, theoretical analysis and engineering practice verification, the occurrence state and migration law of gas in coal rock mass in freezing condition are mastered, which provides theoretical basis for the application of low temperature freezing technology in the local outburst of rock cross-cut coal uncovering. With the help of intelligent liquid nitrogen freezing system, “one hole multi-function” is realized, which provides a new choice and support for the local anti-outburst work of rock cross-cut coal uncovering, so as to quickly and safely uncover the dangerous coal seam of outburst.

With the large-scale mining of coal resources, there are more and more potential hazards of coal mine geological disasters. Coal mine disaster accidents often have the characteristics of suddenness, contingency and complex. Information technology can quickly integrate and process multi-source information, which is an important support for effective rescue. The article is based on the actual situation of coal mine safety production, combined with the business characteristics of geological exploration units, based on the analysis of system requirements, this paper designs the system functions, puts forward the key technologies and implementation methods of system construction, and develops and constructs an information system that meets the actual needs of coal mine geological emergency rescue. Taking a coal mine in Ningnan Coalfield as an example, the rationality of the system function is verified.

The deployment of the front drilling rig requires a significant amount of time before and after water exploration and drainage operations. Loading advanced drilling equipment on the anchor excavator can reduce equipment deployment time and improve drilling efficiency. At present, research on anchor excavator units that integrate excavation, anchoring, and exploration mostly focuses on the structural design of equipment and the design of hydraulic control systems. There is relatively little research on the interference features between different structures. The paper analyzes the interference situation during the attitude adjustment process of the airborne drilling rig. A mathematical model for the interference between the anchor excavator and the airborne drilling rig is established based on the geometric position relationship during the attitude adjustment. The formula for calculating the maximum rotation angle is derived when the anchor excavator interferes with the airborne drilling rig. The maximum angle of interference between the anchor excavator and the airborne drilling rig is taken as the indicator. The influence of various size parameters of the anchor excavator and airborne drilling rig on the maximum angle of the airborne drilling rig in various directions is studied. The results show the following points. ① The larger the inclination angle of the anchor excavator keel, the greater the pitch adjustment angle of the airborne drilling rig. By adjusting the inclination angle of anchor excavator keel, the adjustment range of the elevation angle during the operation of the water exploration drilling rig can be effectively changed. ② The variation of the keel height has little effect on the pitch angle. The variation of the keel height does not affect the variation of the pitch angle, but has a greater impact on the pitch angle, which is proportional. The increase in the length of the keel connecting the twisted ear to the tail of the keel increases the pitch angle, but the effect on the pitch angle is not significant. To change the elevation angle, the value of the keel height can be changed firstly. To change the depression angle, the value of the length of the keel connecting the hinge to the tail of the keel can be changed firstly. ③ When the spacing between the anchor excavator keel protection plates is larger, the maximum horizontal rotation angle of the airborne drilling rig is larger. When it increases to a certain extent, the maximum horizontal rotation angle is no longer affected by the increase in spacing between the anchor excavator keel protection plates. When the distance between the keel protection plates of the anchor excavator is greater than a certain value, the larger the center distance of the support oil cylinder of the anchor excavator, the greater the maximum horizontal rotation angle of the airborne drilling rig. The influence of the spacing between the keel protection plates of the anchor excavator on the maximum horizontal rotation angle of the airborne drilling rig is greater than the center distance of the support oil cylinder of the anchor excavator. ④ When the width of the rear end of the airborne drilling bit is small, it does not affect the maximum horizontal angle. When the width of the rear end of the airborne drilling bit increases to a certain value, the larger the width of the rear end of the airborne drilling bit, the smaller the maximum horizontal angle. When the width of the rear end of the airborne drilling bit is less than a certain value, the larger the width of the front end of the airborne drilling bit, the smaller the maximum horizontal angle. The example verification results show that increasing the inclination angle of the keel, the height of the keel connecting bolts, the height of the keel, and the length of the keel connecting ear to the tail of the keel, while reducing the height difference between the upper edge of the drill bit and the connecting ear of the drill frame, and the length of the keel upper protective plate, effectively increases the maximum pitch angle of the airborne drilling rig.

The paper comprehensively summarizes the process of China's coal mine construction technology from introduction and absorption to independent development since the founding of New China more than 70 years ago, as well as the important achievements in basic research, process innovation, technological breakthrough, equipment development and achievement transformation, involving drilling and blasting method, freezing method, grouting method, drilling method, caisson method and other drilling technology as well as coal mine rock tunneling technology. At present, the mechanization and automation level of drilling and blasting equipment mainly for drilling and blasting rock has been significantly improved, and the comprehensive drilling technology for short-segment excavation of kilometer-level deep wells has been mature, and the maximum depth of vertical shaft drilling has reached 1341.6 m.The level of geological support technology for drilling and tunneling such as freezing method and grouting method has been significantly improved, gradually replacing the curtain method, sheet pile method and dewatering method and other drilling technology. The maximum frozen depth of vertical shaft is 990 m, and the maximum frozen section of inclined shaft is 681 m. The longest inclined shaft of 5875 m is built by working face grouting, and the ground pre-grouting reinforcement depth is 1355 m.Breakthroughs have been made in the technology of mechanical rock breaking and tunneling. The maximum drilling diameter of reverse drilling rig is 6 m, and the maximum drilling depth is 562 m.The maximum drilling diameter of vertical drilling rig is 10.8 m, and the maximum drilling depth is 660 m, and the application range is gradually expanded. The drilling method of vertical tunneling machine has achieved a breakthrough of zero, which has laid a foundation for intelligent drilling of coal mine vertical shaft. The operation line of the mechanized excavation method of the rock tunnel has been formed, and the average tunneling speed of the full section tunneling machine is more than 400 m/month. In summary, the innovation and development of coal in China mine construction technology and equipment in the past 70 years has significantly improved the operation environment, construction efficiency and safety level of the coal mine tunneling, realized the unmanned and fully mechanized operation of the tunneling working face, solved the problems of the tunnel construction in each stage of coal development in China, and ensured the basic construction and mining continuous construction of coal mines. At the same time, the technical equipment developed from the coal mine construction and the successful experience have been promoted and practiced in the underground engineering fields such as hydraulic power generation, municipal rail transit, mountain traffic tunnels, water diversion tunnels, and made contributions to the construction of national key projects and the development of national economy.

The roof breaking movement of steeply inclined and ultra-thick coal seam mining is complex, and the evolution law of stress and energy is special. Under the influence of deep ‘three highs and one disturbance’, the prevention and control of rock burst is not optimistic. Based on the experience of rock burst prevention and control in horizontal section mining of steeply inclined and ultra-thick coal seam after the rock burst accident in a mine in 2016, the experience of rock burst prevention and control in steeply inclined and ultra-thick coal seam in the past seven years is introduced in detail from the mechanism of rock burst in horizontal section mining of steeply inclined and ultra-thick coal seam, the comprehensive prevention and control of gas outburst and rock burst and the management of rock burst. In terms of the mechanism of rock burst, the inclined cantilever beam model of roof strata is established, the evolution process of fracture instability of roof and floor overburden structure is revealed, and the ‘clamping theory’ of rock burst in steeply inclined and ultra-thick coal seam is put forward. In terms of comprehensive prevention and control of gas outburst and rock burst, based on the theory of strength weakening and rock burst reduction of rock burst disaster control and disaster relief technology, combined with the original outburst prevention measures system, this paper puts forward the measures that can prevent and benefit the outburst prevention, forms a mine gas/carbon dioxide outburst/rock burst ‘integrated control’ technology system, and establishes a rock burst prevention and control system suitable for the horizontal section mining of steeply inclined thick coal seam in a mine. The intensity of gas outburst prevention and control is verified by the amount of drilling cuttings and the value of gas absorption and desorption. At the same time, the distribution of microseismic events and the total frequency and energy of each energy level are compared in the working face with pressure relief measures. The effectiveness of the control effect of the pressure relief scheme is demonstrated. In terms of rock burst management, a “six-in-one” comprehensive prevention and control framework has been formed, including prediction and evaluation, monitoring and early warning, treatment and prevention, effect test, safety protection and education and training. Based on the “Coal Mine Safety Regulations” and “Detailed Rules for Prevention and Control of Coal Mine Rock Burst” and other provisions, the Q/YJMD-FC 0104-2022“Yaojie Coal and Electricity Group Co., Ltd. Coal Mine Rock Burst Prevention and Control Part IV: Technical Specification for Prevention and Control of Rock Burst” was formulated.

Karst geology is widely distributed in China, and karst water gushing has become a huge disaster and challenge for the safe production of limestone mines. Taking the large-flow water inflow of a karst sunken open pit mine in Guangxi as the research object, aiming at the characteristics of complex geological conditions, large concentrated water inflow and high flow rate of the mine, the karst development characteristics, data analysis and geophysical exploration methods are used to preliminarily delineate the mine runoff zone area and water source. After that, the specific location of the karst pipeline at the Y01 extra-large water gushing point of the mine was accurately found through drilling, cross-hole CT and tracer connection test. On this basis, the mine water gushing treatment technology and process were studied and implemented. The research shows that: ① In view of the characteristics of large flow and high flow rate in complex karst sunken open pit mines, a comprehensive treatment system of water gushing in karst mines is proposed and implemented, which is “discontinuous curtain closure + key channel exploration and plugging + slurry-stopping cushion to control flow and reduce speed.” According to the inhomogeneity of karst development, the idea of discontinuous curtain plugging fissure water gushing area is put forward. A slurry-stopping pad flow control device was designed for the concentrated water inflow of large-flow karst pipelines. The flow control can effectively reduce the flow velocity in the key water passage, which provides an important condition for the effective retention and deposition of grouting materials and the successful plugging of the project. ② The key hole refers to the drilling hole that directly exposes the karst water gushing pipeline or has strong connectivity with the water gushing pipeline and plays a major role in grouting and water plugging. In this paper, two key holes were successfully found for the large water inflow of Y01 karst pipeline type in the mine, both in the south of the mine. One is a short-distance borehole with a linear distance of about 50 meters from the water inflow point, which is referred to as the near hole, and the other is a long-distance borehole with a linear distance of about 150 meters from the water inflow point, which is referred to as the far hole. The simultaneous grouting process of two key holes, near hole and far hole, is adopted in the field. The near hole is mainly grouted with aggregate, and the far hole is only grouted with slurry. The near hole aggregate can not only reduce the water flow in the pipeline, but also play a better role in retaining and depositing the far hole slurry, and can be used as a plugging material to enhance the function. The far hole can ensure the length and effect of plugging due to its wide radiation range and sufficient slurry diffusion. The simultaneous grouting of near hole and far hole is an effective combination process for rapid plugging of large flow water gushing in pipeline. ③ After the implementation of the project, the Y01 super-large water gushing point with a concentrated water inflow of 71 200 m3/d in the mine was completely blocked, and the total water reduction was 84 300 m3/d (including discontinuous curtain grouting plugging), which ensured the normal and safe mining of the mine, greatly reduced the cost of pumping and drainage, and protected the surrounding environment and groundwater resources, with significant economic and social benefits. The research results can provide important theoretical technology and experience for the treatment of water inrush disaster in karst mines in China.

In order to solve the problem of grasping failure or missing grasping due to the change of target gangue position and posture caused by belt slip, deviation and belt speed fluctuation of belt conveyor when the gangue sorting robot sorts gangue, an improved ORB-FLANN efficient matching method of gangue recognition image and sorting image is proposed. An improved ORB feature point detection method is proposed to detect the feature points in the recognition image and sorting image of coal gangue, so as to realize fast detection of image feature points; An improved FLANN matching algorithm is proposed to match the image feature points to achieve efficient matching between the recognition image of coal gangue and the sorting image. Aiming at the problem of long time and low repetition rate of traditional ORB method for coal gangue image feature detection, an improved ORB feature detection method is proposed to improve the speed and repetition rate of image feature point detection; Aiming at the low accuracy of traditional FLANN matching method for coal gangue image matching, an improved FLANN matching method integrating PROSAC algorithm is proposed to eliminate the wrong feature matching point pairs and improve the accuracy of image matching. The method, SURF feature matching method, HU moment invariant matching method, SIFT feature matching method and ORB feature matching method are applied on the experimental platform of the double mechanical arm truss type gangue sorting robot independently developed by the team to carry out gangue matching experiments under different belt speeds, scales and rotation angles. The results show that the matching rate of the method in this paper is 98.2%, and the matching time is 141 ms. It has the characteristics of high matching rate, good real-time performance and strong robustness, It can meet the requirements of efficient and accurate matching of gangue recognition image and sorting image.

Against the backdrop of achieving the goals of “peak carbon emissions and carbon neutrality”, coal, as the cornerstone of national energy security, plays a crucial role in the green development of our country’s economic construction and social development. However, during the process of coal mining and washing, coal gangue, as the primary associated by-product of coal, has become the foremost bulk solid waste that urgently needs to be addressed in our country. Currently, the comprehensive utilization rate of coal gangue remains at a relatively low level, and a standardized and feasible research system has yet to be established. Therefore, addressing the water, atmospheric, and soil environmental pollution caused by coal mining and coal gangue accumulation, this paper summarizes the relevant research progress on the resource utilization of coal gangue in the production of energy, recovery of valuable metals, production of building materials, and other directions, and also discusses the application of coal gangue in preventing heavy metal pollution, soil remediation, and erosion control. Finally, it proposes the future development direction of coal gangue resource utilization, planning and integrating resources as a whole, not only for conventional purposes but also for the production of high-value-added products. By combining the two, comprehensive and resourceful utilization of coal gangue can be achieved, providing a reference for its “reduction, resource utilization, and recycling” development. In conclusion, the resource utilization of coal gangue is an important direction for the transformation and upgrading of China’s coal industry, and it is also the necessary path to achieve green and sustainable development. Only through unremitting efforts and continuous innovation can we better address the problem of coal gangue accumulation, promote the more efficient, environmentally friendly, and sustainable development of coal gangue resource utilization, and make a greater contribution to the sustainable development of our country’s economy and society.

This is an essay in the field of mineral processing engineering. Lead-zinc mine is one of the important strategic mineral resources in our country, and it is generally poor, fine and complex. Lead-zinc sulfide deposit is about 90% of total reserves. At present, flotation is the most commonly used method for the beneficiation of lead-zinc sulfide ore, and the selection of flotation reagents plays a decisive role in the flotation process index. In this paper, recent research progress of zinc sulfide flotation reagents is summarized, emphatically introduces the collecting agent, inhibitor and activator, analyzes the future the key research direction of zinc sulfide flotation, finally points out that the microbe as flotation reagents zinc sulfide flotation in the broad application prospect in the future, to achieve efficient vulcanization lead-zinc separation to provide technical and theoretical support.

This is an essay in the field of mining engineering. The main minerals of Heishan iron mine are vanadium titanomagnetite and titanomagnetite. Due to the influence of ore properties, the grade of iron concentrate in this type of deposit is generally low and rich in titanium, silicon, magnesium and other elements, which limits the development benefits of this kind of deposit resources. If the grade of iron concentrate can be further improved in the beneficiation process, it will help to improve the mine benefits and reduce the smelting cost of iron concentrate. This paper systematically studies this type of iron ore by means of optical microscope, mineral dissociation analyzer (MLA) and chemical analysis. This type of iron ore was systematically studied by means of optical microscope, mineral dissociation analyzer (MLA) and chemical analysis.

This is an essay in the field of mineral processing engineering. In China, fluorite mainly exists in the form of concomitant deposits. In the flotation process, other useful minerals are usually preferentially floated, and a large amount of fluorite exists in tailings. In this paper, the restrained fluorite and calcite in the floating tungsten tailings are taken as objects, and ultrasonic wave is added to change the floatability of the two, so as to explore a method to optimize the comprehensive utilization level of fluorite in the floating tungsten tailings. After ultrasonic pretreatment of pulp inhibited by sodium humate for 39 min, the flotation recovery of fluorite reached 84.74%, while the flotation recovery of calcite was only 11.47%, with a difference of 73.27%. Exploring the mechanism of ultrasonic pretreatment, it is found that the absorption intensity of sodium humate on the surface of fluorite is lower than that of calcite in the infrared spectrum detection. Ultrasonic pretreatment can desorb the sodium humate on the surface of fluorite, increase the absorption amount of sodium oleate on the surface, and make the zeta potential move forward; In addition, ultrasonic pretreatment mainly affects the content of sodium humate on the mineral surface, but does not affect the content of sodium oleate on the mineral surface. If only sodium humate exists in the slurry system during ultrasonic pretreatment, the sodium humate desorption speed is faster, which is more conducive to adsorbing the sodium oleate added subsequently.

This is an essay in the field of ceramics and composites. For decades, space exploration has been a hot topic. With the launch of Chang'e 5, China officially opened the first extraterrestrial celestial body sampling return journey. The lunar base construction program in China is officially on the agenda. Lunar exploration is the first step for human to conduct deep space exploration, and the utilization of lunar in-situ resources is of great significance for lunar exploration. Additive manufacturing is an effective means to carry out in-situ lunar resource utilization to build a lunar base. This paper describes the basic properties of lunar soil and the characteristics and composition of simulated lunar soil, and focuses on summarizing the current research progress of simulated lunar soil additive manufacturing in China and abroad. Important challenges are presented for the key technology of additive manufacturing for the lunar weathering layer (i.e., lunar soil). The development prospect of additive manufacturing technology and possible ways of implementation are discussed around China's lunar base construction project.

This is an essay in the field of ceramics and composites. To solve the problems of high-cost for cement cementitious material and low strength of cement filling body at the later stage in a lead-zinc mine, abundant slag solid waste resources were adopted and low-cost slag cementitious materials were developed in this paper to meet the quality requirement of mine fillings. After physical and chemical analysis of tailings, slag and cement clinker, the physical and chemical analysis of tailings, slag and cement clinker was carried out. Then, through the filler slurry slump test and the exploration test of the ratio of slag cementitious material, it is determined that the slurry concentration satisfying the fluidity is about 70%, and the ratio of slag to cement clinker is 2~4. The strength, bleeding rate and coagulation characteristics of filling body with different proportions of slag cementitious materials were investigated by comprehensive test. The results show that the ratio of slag cementitious material is 75%~80% slag and 20%~25% cement clinker, the filling body can meet the filling quality requirements of 0.5 ~3.5 MPa compressive strength and the filling slurry bleeding rate is less than 5%.

This is an essay in the field of ceramics and composites. With the rapid development of the new energy vehicle industry, the production of power lithium-ion batteries has increased dramatically. However, due to the short service life of power Li-ion batteries and their imminent mass retirement, it is necessary to effectively manage power Li-ion batteries in a resourceful manner. This paper first introduces the main components of power lithium-ion batteries and clarifies the stepwise utilization and pre-treatment process before their cathode materials are recycled. It focuses on an overview of the thermal, wet and biological recycling technologies for used power lithium-ion battery cathode materials, and presents the opportunities and challenges faced by biological recycling in the resourceful disposal of used power lithium-ion battery cathode materials. Our results can provide a certain reference for the green resource-based recycling of power lithium-ion batteries and promote the healthy development of the new energy vehicle industry.

HZSM-5 molecular sieve is one of the commonly used catalysts for the alkylation of toluene with methanol to para-xylene (PX). This study introduces a one-step method to directly prepare microscale HZSM-5 catalysts with suitable pore structure and acidity. Specifically, this paper combined crystal seed regulation of the morphology of HZSM-5 and adjusted the Si/Al ratios of the precursor solution for HZSM-5 synthesis to regulate the acidic phase of the HZSM-5. It analyzed the phase composition, pore structure parameters, microstructure, and acidity of HZSM-5 molecular sieve through X-ray diffraction, N2 adsorption desorption, SEM, NH3 temperature programmed desorption, pyridine infrared spectroscopy, etc. This study investigated the catalytic performance of HZSM-5 in the alkylation of toluene with methanol to PX, and explored the effects of pore structure and acidity on the catalytic performance. Results indicate that in the hydrothermal crystallization method, the crystal seeds and aluminum content in the synthesis solution have a significant impact on the acidity and morphology structure of the HZSM-5 molecular sieve. The HZSM-5 (150)molecular sieve catalyst with 5μm grain size exhibits 60% PX selectivity and 11% toluene conversion rate in the evaluation reaction of toluene methanol alkylation due to its longer diffusion path and more suitable acidic sites. By fine-tuning the pores and acidic sites of HZSM-5 molecular sieve, the selectivity for PX has been effectively improved, providing new methods and approaches for the design of shape-selective catalysts.

This study aims to tackle the problem of frequent coal-rock dynamic events caused by local stress concentration in deep mining working face under high static stress environment. Specifically, by taking the deep working face of Hongqinghe Mine located in Xinjie Mining Area as an example for analysisthis paper investigates the geological conditions of No. 3-1coal seam that are affected by the mining method and the coal rock dynamic disaster events occurred during mining; utilizes numerical simulation to simulate the mining stress field and energy field of the stope; analyzes the potential coal burst instability area and mechanism of coal burst gestation and catastrophe in the stope during the mining of the No. 3-1103 working face; probes into the sources of catastrophic stress and influencing factors of coal-rock disasters in dangerous areas, puts forward targeted prevention and control measures. Results show that: ① the roof strata structure, goaf and coal pillar are the key factors influencing coal burst in the stope during the mining of the No. 3-1103 working face; ② the simulation results indicatethe location and characteristics of the coal burst instability area in the stope of the No. 3-1103 working faces, as well as the simulation outlines 5 strong coal burst areas and 11 medium coal burst areas presented in the stope; ③ Measures are proposed for coal burst during mining from the perspective of cutting off the dynamic load source, reducing static load stress concentration, and blocking the transmission of high concentration stress. Detailed measures include implementing multi-source prevention and control in areas with high static or high static+dynamic loads, implement pre-pressure off-load measures prior to mining, and local risk relief and coal burst prevention and reduction treatments during mining.

The labor force structure of intelligent coal mine has undergone profound changes as the coal industry transforms from traditional coal mines to intelligent ones. In this light, this study ① reviews the characteristics of the labor force in intelligent coal mine, ② analyzes the interaction mechanism of labor force and labor tools, ③ builds an adaptation model of labor force and labor tools. Specifically, it analyzes the deficiencies existing in the present personnel structure in intelligent coal mine construction from the perspective of labor quality structure, personnel training scale, regulations related to "intelligent replacement", coal mine data management professionals, and term shifts of posts in intelligent coal mines. This paper proposes detailed scheme and measures for career reshaping in intelligent coal mines, namely restructuring intelligent mining personnel structure, creating new posts and new types of work, updating policies and regulations, improving industry image and employee happiness, and improving talent training system.

When the coal-seams are multi-layered, the stress and permeability of the caving zone are disturbed again during the following coal seam mining. Repeated unloading and compaction cause caved coal and rock to break further in the caving zone, which in turn affects the migration of gas in goaf. This paper briefly summarizes prior research on caving zone internal stress, porosity, permeability and other parameters of the process of longwall face advancing. The forecast methods for calculating the stress and permeability of the caved zone during its compaction are listed. On the basis, this paper describes a laboratory experiment of the broken coal and rock in the caving zone of the gob in Huainan coal mine. The laboratory test results imply that the re-crushing, re-arrangement, and compressional deformation of particles in the loading process lead to a drastic drop in the caving zone porosity, which causes the permeability reduction. The permeability sensitivity to stress of broken rock (broken coal) samples was determined by their strength. The greater the proportion of coal samples in the combined coal and rock samples, the higher the permeability stress sensitivity and the smaller the permeability.With the increase of the cyclic times, the stress sensitivity gradually weakened. Based on laboratory experiments, the stress-permeability fitting model of the broken coal and rock in the caving zone during the group coal seam mining is proposed in this paper.

To solve the problems of low positioning accuracy, large deployment of reference nodes and large power consumption of nodes when wireless sensor network (WSN) positioning technology is applied in coal mine target positioning, this paper proposes a method of mine WSN target localization based on the compressed sensing(CS) algorithm. The method designs the target positioning in the offline phase and online monitoring phase based on the needs of mine target positioning and the characteristics of WSN. In the offline phase, the sparse matrix fingerprint database is constructed. In the online monitoring phase, the observation matrix and the measurement value vector are constructed, and combined with fingerprint database, the position signal of the target nodes is reconstructed to realize the accurate positioning of the mine targets. The simulation experiment compares the CS algorithm positioning with two traditional algorithm positioning. The results show that the positioning accuracy of the algorithm in this paper is higher, which can be controlled within 0.8m to meet the positioning requirement.

The application of digital twin technology in the field of intelligent mining needs to face many complex and special technological breakthroughs. This article elaborates on the applicability of digital twins in the field of intelligent mining, and summarizes the research and application status of digital twin technology in coal mine safety, production, and operation management. In terms of coal mine safety management, digital twin technology is mainly applied in disaster warning, risk control, disaster rescue, etc. In terms of coal mine production, digital twin technology is mainly applied in the overall mining working face area, monitoring and control of single machine mechanical equipment status, and predictive maintenance of mechanical equipment. Starting from five dimensions: physical entity, virtual entity, connection interaction, digital twin data, and functional services, this paper explores the key common problems that urgently need to be solved in the field of intelligent mining. The physical entity dimension needs to focus on breaking through the research and development of comprehensive perception and control equipment. The virtual entity dimension needs to conduct in-depth research on physical, behavioral, and rule models. The connection interaction dimension needs to tackle key technologies for underground 5G network transmission in coal mines. The twin data dimension needs to solve problems such as high-performance computing. The functional service dimension needs to develop simulation software and artificial intelligence algorithms to better adapt to the on-site environment. This article looks forward to the development trend of digital twin technology in the field of intelligent mining from the aspects of disaster prevention design, production system design, geological environment prediction in the planning, development, and construction stages of mines, disaster warning and prevention, optimization of production scheduling decisions, and full life cycle management of production equipment in the production and operation stage of mines. It is believed that fine twinning should be carried out for key components or equipment, core links, important or dangerous places, areas, etc.

In order to smoothly implement gob-side entry retaining and mining without coal pillar in 3207 working face of Nanyang Coal Mine,Shanxi Province,this paper proposes to carry out advanced deep-hole blasting pre-splitting roof near gob side supporting wall.Through numerical simulation and field industrial test,the influence of deep-hole blasting roof cutting on surrounding rock stability of gob-side retaining roadway is studied.Based on the backdrop of retaining roadway along goaf in 3207 working face of Nanyang coal mine,a numerical simulation model was established,the displacement of roof and floor,wall and coal body of retained roadway,the stress distribution and variation of surrounding rock of retaining roadway were calculated.The numerical calculation shows that the variation of stress and displacement of surrounding rock in gob-side retaining roadway decreases greatly after roof cutting,and the stability of surrounding rock is improved significantly.The field industrial test results show that deep-hole blasting roof cutting can effectively eliminate the rotational extrusion damage of cantilever beam roof to surrounding rock of gob-side retaining roadway,and help to maintain the stability and integrity of gob-side retaining roadway structure.The research results of this paper can be used for reference in the design and construction of gob-side entry retaining project.

The deep roadway with broken surrounding rock has problems such as insufficient strength of surrounding rock, serious floor heave, etc. It is urgent to strengthen the surrounding rock with effective support means. With the help of COMSOL numerical simulation software, the paper constructs the grouting diffusion model of roadway coupling grouting reinforcement, takes the pressure iso-surface as the grouting diffusion index, obtains the grouting diffusion range under different grouting reinforcement methods, and imports the obtained grouting diffusion range model into 3DEC to study the grouting reinforcement characteristics. After that, taking the surrounding rock reinforcement of belt roadway in 12101 working face of Wangjialing Coal Mine as the engineering background, the different reinforcement effects of the original support mode of belt roadway and deep shallow hole high and low pressure coupling grouting reinforcement are studied. The results show that the grouting diffusion range division method is reasonable and can better meet the engineering practice; compared with the original support method, the roadway safety has been greatly improved by using the coupling grouting support method.

In order to improve the accuracy and reliability of coal seam gas content prediction, this paper proposed the coal seam gas content prediction model (LSSA-BP model) based on Logistic chaotic mapping improved sparrow search algorithm to optimize BP neural network. Firstly, the main control factors of gas content were selected using grey correlation analysis (GRA) as the node number of the input layer of the LSSA-BP prediction model. Then, the sparrow population was initialized by Logistic chaotic mapping to increase the diversity of the population. The problems of slow convergence rate and easy to fall into local minimum of single BP model are solved. Through model application, the prediction results of LSSA-BP, SSA-BP and BP models are compared. The results show that: the mean absolute error (MAE), mean square error (MSE), root mean square error (RMSE) and mean absolute percentage error (MAPE) of LSSA-BP prediction model were 0.346 9 m3/t, 0.172 1 m3/t, 0.414 9 m3/t and 27.4036%, respectively, which were better than other models. The accuracy and stability of coal seam gas content prediction are improved.

In recent years, most of the coal mines in Zhungeer Coalfield have entered the mining of the second main coal seams, such as 6#, 10# and 11#, with an average thickness of more than 10 m, so most of the coal mines use fully mechanized caving mining technology for mining. Affected by the mining of the upper coal seam, the overburden movement, ground pressure appearance and roof weighting source of the lower fully mechanized top coal caving face are more complex. In this paper, the laws of overburden movement and ground pressure appearance of the fully mechanized top coal caving face under the disturbance of the upper coal seam are studied; taking Huangyuchuan 226 upper 02 fully mechanized top coal caving face as an example, by using the methods of theoretical analysis, similar simulation and field measurement. The main conclusions are as follows: before the middle rock stratum is not completely broken, the overburden is characterized by layered collapse, the damage scope develops upward in a stepped manner, and the lower fully mechanized top coal caving face appears small periodic weighting with large weighting step distance and small strength; when the middle rock stratum is completely broken, the damaged areas of the two coal seams will be connected, the overburden will sink in a large range of steps, and the lower fully mechanized top coal caving face is prone to sudden changes in rock pressure such as frame pressing and roof fall; after the middle rock stratum is completely broken, the overburden appears a “bench beam” structure, and the fracture boundary cracks are increasing, the lower fully mechanized top coal caving face appears large periodic weighting, and the weighting step decreases and the strength increases. At the same time, through the research on the movement law of overburden, the source of roof weighting under the upper coal seam disturbance is analyzed, and the calculation method of support load is determined. Taking Huangyuchuan 226 upper 02 fully mechanized top coal caving face as an example, targeted comprehensive control measures such as controlling mining height and increasing support working resistance are formulated, which have achieved good control effect after on-site implementation.

With the gradual increase of coal mining intensity, the production system is more prone to instability, and the occurrence probability and severity of five major coal mine disasters increase gradually. The effect of coal mine disaster control largely depends on all kinds of disaster control materials. The complex physical and chemical interaction between disaster medium and material determines whether the effect can be fully played. On the basis of long-term research on bentonite-based materials, this paper combined with some outstanding properties to solve some technical problems in coal mine disaster prevention and control, and introduced four core interface modification methods, namely, mechanical-chemical modification method, organic activation-inorganic salt modification method, composite coupling agent-surface dispersion method and composite polymer melting intercalation method. A series of disaster prevention materials suitable for different scenarios were developed by directional strengthening modification of bentonite base materials.

To identify the key factors and potential moderating variables influencing coal miners’ unsafe behaviors in the intelligent change of China’s coal mines and to explore the reasons for inconsistent research findings, a quantitative literature analysis was conducted using meta-analysis on 24 empirical papers with 71 effect values to identify 12 key influencing factors and to test the moderating effects of four variables: sample size, survey area, type of literature, and year of publication. The results indicated that, in addition to leadership style and management system, insecurity psychology, work engagement, and safety supervision had high effect size, subjective well-being, organizational equity, safety attitudes, mental wandering, affective emotions, and interpersonal relationships had moderate effect size, and safety climate had low effect size. It was also found that using sample size, survey region, year of publication, and type of literature as moderating variables could partially reveal the differences between studies.

Aiming at the surrounding rock control problem of double basic roof cutting and retaining roadway in inclined soft and hard rock strata, this paper expounds on the comprehensive roadway protection mechanism of goaf side-roof-solid coal side under this geological condition, and puts forward the comprehensive control technology of goaf side “U-shaped steel roof cutting and bottom cutting + high strength anchor cable + metal mesh gangue retaining”, retaining roof “groove steel truss anchor cable + roof cutting anchor cable + single pillar roof”, and solid coal side “groove steel truss anchor cable strong anchoring”. On this basis, the blasting roof cutting parameters such as hole layout form, hole spacing and angle, hole layout depth, charge parameters and sealing mud length are designed. The field results show that the roof cutting hole of about 9.5 m is beneficial to the surrounding rock control of roof cutting and retaining roadway in inclined soft and hard rock strata. The final deformation of the roof and solid coal side of the cutting seam is about 192 mm and 119 mm, which ensures the safe mining of the lower working face.

Intelligence is the direction of coal mine development, and intelligent video analysis is an effective way to promote coal mine intelligence. The mine-wide intelligent video analysis technology has real-time monitoring, early warning, and decision support capabilities. It helps to improve the safety, production efficiency, resource utilization efficiency, and environmental sustainability of mining enterprises. The key technologies of mine-wide intelligent video analysis are introduced in detail, including video acquisition and processing technologies such as video acquisition equipment, video pre-processing, video compression and coding, basic video analysis technologies such as object detection and tracking, motion detection and analysis, object recognition and classification, and advanced video analysis technologies such as behaviour recognition and analysis, event detection and alarm, video monitoring and arming. A mining intelligent AI visual intelligence service platform that integrates video recognition analysis and industrial linkage control functions is developed. The paper introduces the application of intelligent video analysis technology in mining production scenarios such as intelligent water and gas exploration and discharge systems, coal rock recognition and cutting systems, heading working faces, fully mechanized working faces, coal flow transportation systems, mine hoist systems, auxiliary transportation systems, coal preparation plants, and intelligent loading and coal blending systems. The analysis points out that the current mine-wide intelligent video analysis technology still faces challenges in terms of video quality, complex backgrounds, real-time requirements, data privacy and security, system reliability and stability, etc. It is suggested to strengthen the research on algorithm improvement and optimization, multimodal data fusion, real-time analysis and edge computing, enhanced learning and independent decision-making, data privacy and security protection, hardware equipment and sensor technology in the future. Therefore, the development of mine-wide intelligent video analysis technology is comprehensively promoted and promote the process of mine intelligence is promoted.