The environmental conditions in underground mines are harsh.In recent years，with the continuous increase in the mining depth of underground mines and the improvement of mining technology requirements，the underground mines are faced with the bad environment of high temperature and high ground pressure，and the working conditions of underground mines workers have become more complex.Ensuring the safety and health of underground personnel is of great significance to promote the stable development of mining enterprises，and it is also one of the core contents of contemporary mine intelligent construction.Therefore，with the rapid development of technologies in the fields of big data，Internet of Things（IOT），unmanned driving and three-dimensional visualization，it is imperative to develop the automation and intelligence of underground equipment.For underground mines，the high-precision autonomous positioning technology of downhole equip-ment is one of the key technologies to promote underground intelligent mining，and it is also the basic guarantee for the realization of automated mining of underground mining equipment.High-precision positioning can ensure that underground personnel and equipment are within an accurate measurable range.At the same time，it is also particularly critical to advance the construction of underground unmanned equipment mining platforms （such as the development of underground LHD）.Based on the existing research results of high-precision positioning of underground equipment at home and aboard，after analyzing its development status，the categories of downhole equipment positioning sensors and the latest positioning technologies developed on this basis were summarized，which can be divided into two categories：One is the positioning technology that requires the addition of external equipment in the mine environment for auxiliary positioning，and the other is the positioning technology that only relies on the sensors carried by the equipment itself.The core technology and development prospects of underground mine high-precision positioning were put forward.This paper mainly introduces the current technical status，technical characteristics and development trend of underground mines equipment positioning.Firstly，the environmental sensing sensors commonly used in underground mines was summarized.Then，according to the technical means，hardware basis and algorithm characteristics of un-derground equipment positioning，the current research results were classified and analyzed.After analyzing and comparing the advantages and disadvantages of various positioning technologies，a summary and prospect were made，and it is considered that multi-sensor fusion technology without the assistance of external equipment（such as SLAM-based positioning method） is the inevitable trend of underground equipment positioning development in underground mines，so as to ensure the stability and accuracy of underground mine positioning to promote mine development smoothly entered the stage of true intelligence.
At present，many mines still rely on human supervision to supervise the unsafe behavior of mining truck drivers，and cannot find problems timely and accurately.This consumes a certain amount of manpower and material resources but cannot solve the problem.With the development of computer technology and artificial intelligence technology，more and more fields are beginning to use artificial intelligence technology to supervise the unsafe behavior of mining truck drivers，such as intelligent security，unmanned driving，and intelligent transportation.Behavior recognition is a hot issue in the field of computer vision.Using computer technology to identify unsafe behaviors is an efficient way to replace manual detection.This paper uses deep learning to solve the unsafe behavior recognition of mining truck drivers in video sequences.The traditional deep learning method does not rely on artificial design features，but adaptively learns better high-dimensional features，better robustness，and faster speed，the accuracy rate is higher.Firstly，according to the actual obtained video data，by analyzing the relative position relationship between the camera and the driver’s area，the video is clipped to obtain video data with less redundant information.At the same time，in order to reduce the imbalance of the data samples，by using flipping，methods such as panning and adding noise were used to enhance the data set，and then use Opencv to re-convert the enhanced image data into a video file and use the dense_flow method to obtain an optical flow diagram.Secondly，use the network for training and testing.In order to conduct com-parative experiments，firstly，a traditional classification model that does not consider time sequence information was used for training and testing，and the transfer learning method was used to train Resnet，Xception，and Inception.And fusion of three single models to get a new fusion model.At the same time，the time domain and spatial domain channels of the dual-stream network model are set to the pre-trained VGG16 using migration learning under the consideration of timing information，and the comparison experiment was carried out with the C3D-two-stream proposed in this paper.The experimental results show that the improved Vgg-two-stream model can reach an accuracy rate of 89.539%，and the accuracy rate of the C3D-two-stream model can reach 93.445%.In summary，the C3D-two-stream model proposed in this paper has a high recognition rate.It also proves that for behavior recognition，the acquisition of characteristic information in the time dimension can make the recognition results more accurate，which has important practical significance for the recognition of unsafe behaviors of mining truck drivers.
With the increase of mining depth，the mining operation environment is worse and worse.It is of great significance to realize the underground unmanned load-haul-dump（LHD） machine to ensure the safe and efficient production of mine enterprises.In underground operation，the long，low articulated body of under-ground LHD machine has the characteristics of high mass，high inertia and high steering delay，which makes the precise tracking of the scraper path a difficult point for its realization of unmanned driving.As an important technique of path tracing control，the control algorithm based on optimization principle often has the problem of parameter selection and adjustment.In industrial applications，manual trial-and-error methods are commonly used for parameter selection.This method not only consumes a lot of human and time costs，but also makes it difficult to ensure the accuracy because of the lack of relevant experience of the operator.In this paper，the method of parameter optimization for linear quadratic regulator（LQR） state feedback controller by quantum-behaved particle swarm optimization（QPSO） algorithm was proposed.The LQR state feedback controller was cons-tructed based on error dynamics model.After parameter optimization，the maximum lateral error of path tracking is not more than 0.23 m.In a large number of repeated experiments，it is found that the standard particle swarm optimization（PSO） algorithm is difficult to find the proper parameter that can make the controller cross deviation lower than 0.5 m in 100 iterations.The QPSO algorithm has found the optimal parameter which meets the condition in the 10 repeated experiments.In 100 iterations，the fitness of the PSO algorithm tends to converge at 21 iterations，while that of the QPSO algorithm converges to a lower level than that of the PSO in the seventh iteration.The maximal lateral position deviation of the path tracking controller is reduced by 53.4%.It can be seen that the parameter optimization ability of the QPSO algorithm is obviously stronger than that of the PSO algorithm.The QPSO algorithm has faster optimization speed and higher success rate than the PSO algorithm.The control parameters of the LQR state feedback controller are automated by the QPSO algorithm.The design and parameter tuning process of the entire path tracking controller has important reference significance for realizing the unmanned driving of underground LHD machine.
With the depletion of resources in open-pit mines，metal mines are gradually turning to deep mining. As the main equipment for loading and transporting ores in underground metal mines，the working environment of LHD（Load-Haul-Dump） is further deteriorated.The problems of harmful gases （CO，H2S，NH4，etc.），vibration，high stress and high temperature seriously affect people’s health.In order to protect the life health and personal safety of operators，improve the efficiency of mine operation and increase the economic benefits of mine，the intelligent mining technology of metal mine has been developed rapidly.The research on the automation of LHD has been carried out for more than 30 years，but the commercial system which has not fully realized the automatic loading can not be put into use.Because the shoveling is a dynamic and non-linear process，it is difficult to predict the change，which is the difficulty to realize the autonomous loading of LHD.In order to realize the full-automatic operation of LHD，this paper systematically studied the status quo and development trend of autonomous shoveling and loading of underground LHD，comprehensively summarized the three aspects of environmental perception and modeling，bucket trajectory control and automatic weighing，and analyzed the research status and shortcomings of its key technologies.The research results show that the environmental perception and modeling in the process of shoveling is mainly to establish the three-dimensional model of ore heap，and single type of sensor has shortcomings.Comprehensive use of the advantages of each sensor，information complementary and optimal combination can be realized.The interaction process between bucket and ore has the characteristics of dynamic change and non-linear，and the bucket trajectory control based on force is suitable for uniform medium，so it is difficult to apply in actual production.Reinforcement learning is widely used in the field of automatic control，through self-learning and adaptive environment to complete the operation task.The automatic weighing system can measure the effective load of the bucket and adjust the state of the ore in the bucket to prevent the ore from falling.There is a big gap in the research on the automatic weighing system at home and abroad.Compared with foreign countries，the automatic weighing technology in China is relatively backward，at the same time，the automatic weighing technology is mostly used in the ground loader，less in the underground.At present，there is also a big gap between China and foreign countries in the research of self loading technology of underground scraper.Strengthening cooperation in related fields and carrying out field test of LHD are the key points to promote the development of LHD in China.
Intelligent mining is the mainstream direction of the future development of open-pit mines.Eelectric shovel is the main production equipment of open-pit mines，so the study of electric shovel autonomous shoveling technology is one of the core steps to realize the intelligent mining of open-pit mines in the future.During the autonomous shoveling process，the electric shovel uses its excavation mechanism，shovels the ore out of the mine and dumps the ore into a transport truck that the ore has been parked at the dump position.When the shovel has finished loading the ore shovel in the corresponding mining area of the current working position，it will slowly move through its moving mechanism to the next position point and continue to shovel the ore pile in the target area.Because of the huge volume of the electric shovel itself，the continuous work of the excavation mechanism and the moving mechanism consume a lot of electric energy. In order to improve the efficiency of the electric shovel in the process of autonomous shoveling，reduce the energy consumption of the electric shovel work，this paper proposed a method of optimizing the moving route of the shovel，by planning the electric shovel moving route and digging area，shortening the length of the electric shovel moving route.A method for optimizing the mobile route of electric shoveling was proposed.On the basis of the known electric shovel working area，in order to excavate all the ore piles in the working area and the electric shovel moves the least number of times，greedy algorithm was used to plan the set of job locations where the shovel moves the least number of times.By increasing the transition point and other ways to further optimize the electric shovel movement path and adjust the corresponding mining area planning，to form the optimal trajectory of the final electric shovel operation.Selecting the ore pile after blasting in an area in a mine aerial map as an electric shovel to be shoveled，based on the above method， the mobile route of electric shovel loading was optimized.The results show that the total distance of the generated electric shovel moving path is short，and the planned excavation area meets the actual production requirements，which proves that the method can provide guidance for the movement trajectory planning of the autonomous shovel.
The southwestern Guizhou gold ore concentration area is one of the most important parts of the Yunnan-Guizhou-Guangxi “golden triangle” in southwestern China，its deep and peripheral prospecting work is facing a dilemma.At present，traditional geochemical methods face great challenges in the exploration of deep hydrothermal minerals （such as carlin-type gold deposits in southwest Guizhou）.In order to break through the difficulties of traditional geochemical prospecting methods in the exploration of deep mineral resources，the peripheral area of Nibao gold deposit was selected for a comparative study on the extraction of weak information of 1∶50 000 soil geochemistry and 1∶50 000 tectono-geochemistry.Through the comparative study of soil geochemical survey in the same region，it is found that the method of extracting weak information of tectono-geochemistry has the following characteristics：（1） The anomaly has good reproducibility，within the range of anomalies delineated by soil geochemistry，the extraction of weak information of tectono-geochemistry can also delineate anomalies.（2）The details are more obvious，and the anomaly area obtained by the extraction of tectono-geochemical weak information is larger in the area of soil geochemical anomalies，which can obviously magnify the “high，large and complete” anomalies and strengthen some anomalies.（3）The value of high value point increases exponentially，and the highest content of Au obtained from the weak information of tectono-geochemistry is tens of times higher than that of soil geochemistry，which can highlight the high anomaly.（4）The extraction of weak information is more effective and can form anomalies in the areas where the soil geochemical survey does not show anomalies，indicating that this method plays a good role in the extraction of weak mineralization information and the location and prediction of concealed deposits.（5）The number of tectono-geochemical weak information samples is only 60% of that of the same scale soil samples，the sampling intensity is significantly reduced，and the economy is prominent.In conclusion，the results show that the tectono-geochemistry is not only more effective to extract the weak mineralization information，but also has the characteristics of economy，practicality and efficient.According to the characteristics of geology and tectono-geochemistry，four comprehensive anomalies are delineated.Through the engineering verification of No.2 anomaly with better metallogenic conditions，the remarkable prospecting results have been obtained. Com-prehensive results of geology and geochemistry in the study area show that the tectono-geochemistry weak information extraction provides a scientific basis for deep prospecting in the periphery of Nibao gold deposit. After further improvement and application，tectono-geochemical weak information extraction methods is expected to play an important role in prospecting for carlin-type gold deposits in southwestern Guizhou.
Liyuan gold deposit，a medium-sized gold deposit discovered in Lingqiu district，Shanxi Province，is located at the polymetallic metallogenic belt in the northern section of Taihang Mountain.The outcrop strata in the mining area is the Neo-Archean Fuping Group，which mainly consists of migmatite，gneiss and amphibolites.Faults are well developed and can be divided into four groups of NNE，NE，NW and near EW-trending among which the NNE-trending fault is the main ore-controlling structure.The orebodies mainly occur in the NNE-trending fault zone.In this study，a total of 677 tectonic geochemical samples were collected，and the contents of thirteen trace elements （Cu，Pb，Ni，Mn，Ag，Zn，Co，B，As，Sb，Bi，Hg，Au） were analyzed.The lower limit of each element anomaly is calculated by iterative method.Through correlation analysis，R cluster analysis and oblique factor analysis，the correlation of each element was studied，and the geological and geochemical environment of the Liyuan gold deposit was analyzed.The research result shows that the metallogenic element Au has a good correlation with Bi element，and bismuth minerals play an indicative role in mineralization.However，the correlation between Au and other elements is weak，shows the relative independence of gold during mineralization.Based on the above analysis，abnormal combinations of multiple geochemical elements are complete in the deposit，and can be classified as follows：Metallogenic element is Au，direct indicator elements are Cu-Pb-Zn-Ag，and indirect indicator elements are As-Sb-Hg.The denudation degree of the deposit is low.Spatial distribution of abnormal combinations shows that ore-forming element （Au） anomalies are mainly distributed in granite，diabase dike and strata with intense limonization.The distribution direction is NE-SW-trending，consistent with the regional tectonic line，and the gold mineralization is obviously controlled by the rock mass and the broken zone.The distribution range of abnormal assemblage of direct indicating elements overlap with that of metallogenic element，Au，Ag，Cu，Pb，Zn are the near-ore hole association，whose strong anomaly plays an important role in indicating gold mineralization.Also，this combination has great significance for concealed orebody.Indirect indicator element combination anomaly is mainly located in the distribution area of granite and diabase vein，indicating that the metallogenic rock body and the ore-forming process are rich of Cu elements.The strong anomaly of As，Sb and Hg indicates the upper and the leading edge of the ore body，which is closely related to gold mineralization.Therefore，the tectono-geochemical characteristic of Liyuan gold deposit was analyzed，which has certain instruction significance in metallogenic prediction and enriching the geochemical model of gold deposit in the study area.
A large number of medium-large gold deposits developed in the Xuefeng arc-shaped structural belt，which mainly composed of precambrian strata and undergo low-grade metamorphism with multi-stage tectonic movement.In addition，long-term large-scale magma activity （e.g. Silurian，Triassic） occurred in the Taojiang-Chengbu fault zone on the eastern margin of Xuefeng Mountain.Due to the overprint of regional metamorphic hydrothermal and deep magma hydrothermal fluid，both metamorphic hydrothermal and magmatic hydrothermal Au-Sb deposits are occurred in Xuefeng Mountain region.Previous research and exploration mainly focused on gold deposits in the northern and middle district of the metallogenic belt，that is lacking in the southern district （e.g. Huitong，Jingzhou，Tongdao）.The gold deposits in the Tongdao County are composed of the Chaxi，Jinkeng，and Huanggou small-medium quartz vein and altered rock type gold deposits，which developed in low-grade precambrian metamorphic strata and controlled by faults.To constrain the ore forming fluids characteristics and source，field investigations，microscopic rock-mineral determination，fluid inclusion and H-O-S isotope analysis were completed in this research.The representative ore-bearing quartz vein samples were selected to identify the petrographic characteristics of inclusions for micro-thermal analysis.In addition，the H，O isotope composition were analyzed with a single mineral of quartz and the in-situ S isotope analysis of gold-bearing sulfides （e.g. pyrite and arsenopyrite） are obtained by LA-ICP-MS.Analysis results show that it can be divided into two metallogenic stages，stage Ⅰ is quartz+pyrite+arsenopyrite+sericite+gold，stage Ⅱ is quartz+sericite+minor gold.The homogenization temperature of stage Ⅰ quartz fluid inclusions in the Chaxi deposit is 155~297 ℃ with a peak value of 210~220 ℃ and the salinity［w（NaCl）］ is 4.9%~11.7%.The homogenization temperature of stage Ⅱ quartz fluid inclusions in the Chaxi deposit is 135~233 ℃ with a peak value of 160~170 ℃ and the salinity is 3.3%~9.7%.The homogenization temperature of quartz fluid inclusions in the Jinkeng deposit is 202~261 ℃ with a peak value of 210~220 ℃ and the salinity is 5.6%~10.1%.The homogenization temperature of stage Ⅱ quartz fluid inclusions in the Jinkeng deposit is 134~203 ℃ with a peak value of 150~160 ℃ and the salinity is 3.8%~8.8%.The homogenization temperature of stage Ⅰ quartz fluid inclusions in the Huanggou deposit is 176~319 ℃ with a peak value of 220~240 ℃ and the salinity is 5.1%~11.7%.The H-O isotopic composition of the ore-forming fluids in the three deposits has a similar evolution trend：The stage Ⅰ δ18Ofluid change from +4.95‰ to +6.95‰ and the stage Ⅱ δ18Ofluid change from +1.08‰ to +1.38‰，while the δD value changes greatly，from -83‰ to -33‰.Therefore，the stage Ⅰ ore-forming fluid is a medium-temperature and medium-low-salinity fluid，the source of which are dominated by metamorphic water with overprint of deep magma water and the stage Ⅱ ore-forming fluid is a low-temperature and low-salinity fluid，indicating an addition of meteoric water.In addition，the δ34S values of pyrite in the Huanggou deposit is scattered，ranging from -15.79‰ to +3.88‰，while the δ34S values of sulfide in the Jinkeng deposit is concentrated，which is -5.02‰~+0.74‰.Combined with the sulfur isotope composition of regional strata and the EPMA analysis of pyrite，it is believed that the sulfur source of gold-bearing sulfide （δ34S value near zero） is mainly originated from deep magmatic，but no gold or with trace gold content sulfide （negative δ34S value） are derived from wall rock formation.
With the rapid development of digital mine，3DMine software has been widely used in mine design institutes.However，for multi-layer gently inclined thin ore group，the traditional two-dimensional underground mining development design mode has some problems，such as low design efficiency，heavy workload and difficult to determine the optimal reference location of development shaft.Under the guidance of the concept of synergetic mining，the 3D synergetic design of shaft location was carried out to accurately plan the spatial layout of the development shaft，improve the efficiency of mining design and ensure the effectiveness of the design scheme.Taking Tongkeng zinc polymetallic deposit in Guangxi Huaxi Group as the engineering background，and referring to the traditional two-dimensional transport work calculation model，considering the influence of ore volume and different burial depth on transport work，a three-dimensional transport work calculation model was established based on straight line distance，and then the vertical shaft development arrangement was optimized and the competition problem of transportation work was dealt with cooperatively.According to the determination method of rock movement parameters recommended by Mining Survey Research Institute in Soviet Union，in the Tongkeng zinc polymetallic mine case，the rock is classified into layered rock mass and rock movement characteristics.Combined with the occurrence form，engineering geological condition，hydro-geological condition，surface topography，geological structure，mining method and rock mass mechanical parameters of the orebody，the rock movement angle of the upper，lower and end of the orebody is determined to be 75% with reference to the actual data of the surface rock displacement of similar mines.With the aid of 3DMine software，the scope of rock movement was delineated，and combined with the proposed three-dimensional transport work calculation model，the preliminary selection scheme of shaft development was given.The set pair analysis method was used to optimize the development preliminary selection scheme with four evaluation indexes of safety，resource utilization rate，transportation work and economic investment.The results show that，based on the three-dimensional transportation work calculation model，the optimal scheme is “newly excavated mixed well and using the No.3 and No.4 blind inclined well development scheme”. Results of this study indicate that，based on the three-dimensional transport work calculation model under the straight-line distance，the transportation competition relationship among different buried depths of the seam is coordinated，which makes up for the shortcomings of the transport work calculation model in the development design，and can accurately plan the optimal spatial reference layout location of development shaft from the three-dimensional perspective，thus providing useful reference for development design.
The study area，Sanshandao gold mine，is the first coastal mine in China.It belongs to structural fissure water-filled mine，and the hydrogeological conditions are complicated.With the mining of the orebody，multiple water inrush accidents occurred in the shallow and deep parts of the mine，causing the partial roadway to be flooded，and even some sections were accompanied by sand erosion.Water inrush caused by coastal mining is an extreme threat to the safe production of the mine.Therefore，it is important to determine the mine water mixing ratios and analyze its evolutionary law for the prevention of water inrush accidents.The power-law rule is a general law shown in the occurrence of geological disasters in nature.It refers to the relationship between the frequency and the scale of disasters.The frequency of large-scale disasters is low.Conversely，disasters with a high frequency of occurrence are relatively small in scale.To determine the measure of the proportion of seawater，the power-law rule was applied to the statistical analysis of the mixing ratios of the mine water in this study area.Firstly，the results of two existing mixing ratio studies were statistically sorted out，and the probability density statistical results of seawater fluctuation events were obtained.Then，the probability density function p（S） was used to fit the fluctuation events of the seawater ratio in two adjacent monitoring periods.Finally，by integrating the fitted curve，the early warning interval of seawater fluctuation value was obtained.The research results show that the correlation coefficients of the fitting reach 0.92 and 0.93，respectively.It indicates that the distribution of the interval mean value and probability density of seawater proportional fluctuation events conformed to the power-law distribution.Thus，it is credible to use the power-law rule to analyze the mixing ratio of the mine water in the study area.For the mixing ratios obtained by different methods，the law reflected under the power law rule is the same.The fluctuation values of the seawater ratio at most monitoring sites are not large，less than 30%.It shows that the power-law rule is not affected by the calculation method of mixing ratio.Because the selected analysis index is the seawater fluctuation value，that is，for the relative value of two monitoring periods，the errors caused by different methods are eliminated.The probability that the fluctuation value of seawater ratio is greater than 48% is less than 5%，so 48% is regarded as the critical value of the warning interval.When the seawater fluctuation value is greater than this value，it should be paid attention to，and combined with the water temperature，flow rate，and other indicators of the water site for further analysis.Water samples near the F3 fault have larger fluctuation values of seawater than that of other water samples because F3 connects the seawater，and due to mining，the water channels around F3 are complicated and unstable.
High in-situ stress is one of the main properties of deep rock mass.As the depth of mining，tunnel excavation，etc. increases continuously，the high in-situ stress in deep rock mass represses the effect of water-coupling blasting.Therefore，how to apply the method of water-coupling blasting in breaking deep rock mass with an aim of whether inducing considerable fracture and fragmentation of rock or obtaining the optimal economic benefit has become an essential problem in the field of blasting engineering.In order to study the mechanism of crack propagation under water-coupling blasting in deep rock mass with high in-situ stress，based on the RHT material model verified by experimental results，a series of numerical models were built and the multi-core dynamic analysis finite element software LS-DYNA was applied to simulate the crack propagation of a single hole with a water-coupling charge under different in-situ stress conditions.Numerical models were built under condition that decoupling coefficients were set to 1.11 to 10，with in-situ stress of 0，10，20，30，40 and 50 MPa.The process of crack propagation under water-coupling blasting with high in-situ stress was first analyzed，and then the influence of in-situ stress on the water-coupled blasting was investigated.A comparison of the results of rock blasting with air and water was conducted.And the rock crack evolution with different water-coupled coefficients and different ground stresses was studied.According to the simulation，the water-coupling blasting under high in-situ stress generates three damage zones，i.e. the crushed zone，the nonlinear fracture zone and the radial crack propagation zone.The water-coupling method prolongs the time of explosion and increases the peak radial stress and PPV in rock mass，and it makes the effect of rock blasting better.In-situ stress plays a role in increasing stress and PPV of rock mass under water-coupled blasting in deep rock mass，and high in-situ stress significant inhibits the rock crack propagation in radial crack propagation zone but has no much influence in crushing zone and nonlinear fracture zone.With the decrease of water-decoupling coefficient，the extent of rock fracture increases rapidly.The optimal water-decoupling coefficient exists under different in-situ stresses，by considering the utilization of explosive energy，and the optimal decoupling coefficient decreases with the increase of in-situ stress.The optimal water-decoupling coefficients at in-situ stresses of 0，10，20，30 and 40 MPa are 5.00，3.30，2.63，1.56 and 1.25，respectively.This study provides not only an analysis of the rock crack evolution under the combination of water-coupled blasting and high in-situ stress but also a reference for resolving excavation difficulties in deep rock mass.
To discuss the feasibility of the application of virtual reality technology in mineral processing design，and to solve the problems of long design cycle，low design efficiency and boring design process，which still exist in traditional mineral processing design，a desktop auto-design system of the grinding-classification process was developed in combination with the rapidly rising virtual reality technology.The development of this system takes virtual reality technology platform Unreal Engine 4 as the carrier，and relies on its Blueprint system and Unreal Motion Graphics UI Designer editor to build the whole process.In the process of development，focusing on the empirical formulas，empirical data，equipment selection parameters and equipment selection methods in the traditional grinding and classification process design，the blueprint programming language was used to transform them into a computer-based independent design method.The empirical formulas with complex structure，variable parameters and repeated use are converted into Blueprint system function or macro，the corresponding data of the table are stored as Blueprint array，the value range data are fitted into interpolation function，power function and other mathematical models，and then all of them are stored in the Event Chart of the Blueprint system.Simulation designer in the traditional design methods，using Blueprint design language to write algorithm procedures.After programming and testing，the system is compiled and packaged with Visual Studio 2019，and the Unreal Editor is used to release the Windows version for users to use.According to the original ore data and ore-dressing indexes input by the user，the system recommends the appropriate grinding process，and then，according to the recommended grinding classification process，carries out the calculation of ore volume and pulp indexes，grinding and grading equipment selection calculation，auxiliary equipment selection calculation，etc.，and finally forms a reasonable grinding classification process design scheme.In the process of system design，users can also reasonably change the conditions in the process according to the design requirements.The development of this system has proved that the application of virtual reality technology in mineral processing design is feasible.It has created conditions for the following development of the grinding workshop configuration design system based on virtual reality technology，and also provided useful reference for virtual reality technology to integrate into the mineral processing field.
Meishan iron mine adopts the ventilation system of four-stage progressive return fan station，with many main fans and wide distribution.In order to strengthen the management of ventilation system，the remote control system of multi-stage fan station of the mine was gradually established in 2006.Main fans are equipped with frequency converter，total installed capacity of 15 main fans is 2 730 kW，actual power consumption of full-time operation is 1 940.76 kW，and the annual ventilation cost is up to 14.4509 million Yuan.If the ventilation of working faces with constant air volume according to the maximum demand，it shall be inevitably result in the waste of air volume and energy consumption.At present，changing the characteristic curves of the main fans to adjust the air volume can be achieved by adjusting the installation angle of the blade or the frequency conversion of 1 Hz amplitude，but this method is time-consuming，laborious and difficult，and the method of precise frequency modulation to adjust the air volume is relatively weak.Therefore，based on the theory of “balance of supply and demand”，ventilation period is divided into three，according to the number of mining face，driving working face，other working faces and chambers，and given a certain air leakage coefficient to determine the actual air volume in three periods for ventilation on demand，which can maximize the effect of ventilation and energy saving.According to the relationship between frequency，rotation speed and air volume in the theory of electromotor and fluid mechanics，the actual operating frequency of each main fan meeting the mine air demand in three periods was calculated accurately.Each main fan is precisely and remotely frequency modulated by PLC remote control system，which simplifies the complicated regulation mode of ventilation management personnel adjusting air volume by frequency 1 Hz.After normal operation，the actual air volume in three periods can meet the requirements，and the actual power consumption in each period is 1 093.28 kW，1 385.06 kW and 1 786.38 kW.Through the implementation of research plan of multi time precise frequency conversion and energy saving ventilation technology，the ventilation cost of mine ventilation system is saved by 3.865 million Yuan per year，which solves the problems of air volume，energy consumption and waste caused by full ventilation of the mine ventilation system.The effect is remarkable，which embodies the advanced nature of modern mine ventilation and energy saving technology，and fully displays the advantages of multi-stage time station frequency conversion ventilation “intelligent” energy saving.
The mining of mineral resources is getting deeper and deeper，the working environment is bad，the employees are aging seriously，and the human cost is rising，which brings great challenges to the development of mining industry.Intelligent mine operation has become an inevitable trend.As a part of mine intellec-tualization，unmanned transportation system is very important for mine，which means the improvement of safety production efficiency can achieve zero injury and zero time loss.Considering the development demand of driverless electric vehicle and the traditional computer vision method，it is difficult to realize the real-time detection and location of obstacles.An intelligent obstacle detection method based on the combination of traditional computer vision technology and deep learning target detection algorithm YOLOv3 was proposed.First of all，the video data of obstacles in the driving area of electric locomotive（this paper calls it effective detection area） were collected，using an image annotation tool namely labelimg to make VOC data set，using YOLOv3 to train data set，according to the feedback results，adjust the parameters continuously to obtain the relative optimal parameters，and finally get the obstacle detection model.Then use the traditional computer vision technology to locate the track by edge，texture and other information，using the “3 neighborhood” search method to get the track line coordinate value of left and right track lines，and expand a certain distance to the outside of the track according to the distance information，extracting the effective detection area，thus reducing the computational complexity of the later obstacle detection，at the same time，gridding images，converting the coordinates of obstacles to the actual distance.Finally，using the obstacle detection model to detect the effective detection area and respond to the detection results.Experimental results show that the method can identify many objects with different characteristics in the driving area，such as electric locomotive，people，large falling rocks，etc.It can process 6 pictures per second，and the average accuracy of the actual data collected in the field reaches 93.2%，it has good performance in real-time and accuracy，and has a good effect in the underground mine scene.
From June 2017 to April 2018，frequent pipe plugging accidents occurred in the underground filling of Linglong gold mine，which required a lot of manpower and material resources to restore the pipeline，greatly reducing the filling efficiency.The pipe plugging accident has seriously affected the normal production of the mine and has become one of the factors restricting the development of mine filling technology.In the filling process，the mixing station for filling slurry is generally set on the ground.After the water，full tailings and material C are fully mixed in the mixing barrel，they are transported to the underground goaf through the filling pipeline.The temperature difference between winter and summer in northern China is 30 ℃ to 40 ℃.The hydration reaction of cement is greatly affected by the temperature when the slurry is stirred.When the filling slurry enters the underground through the pipeline，it will be affected by the ground temperature，resulting in the change of slurry temperature.Therefore，the rheological characteristics of the filling slurry in the pipeline are always changing.The rate of cement hydration is greatly affected by the temperature，so the fluidity of the filling slurry will change in different transportation time.Therefore，it is necessary to study the influence of temperature change on the flow performance of the filling slurry.However，there is relatively few research on the influence of temperature change on the hydration of cement.In this paper，the flow characteristics of the filling slurry with full tailings at 20 ℃，15 ℃，10 ℃ and 5 ℃ were studied.According to the actual situation of the mine and the past research in the laboratory，the design slurry concentration is 65% and 68% respectively，and the ash sand ratio is 1∶8 and 1∶12 respectively.The time when material C，tailing and water are mixed together is taken as the starting point of timing.The Origin software was used to process 13 440 experimental data，at each temperature，then we get the shear rate-shear stress curves of different slurry ratio，slurry viscosity coefficient，line graph of relationship between slurry yield stress and slurry temperature and slurry temperature relationship line chart.Through the analysis，the following conclusions are obtained：In the same reaction time，the viscosity coefficient decreases with the increase of temperature；In the same reaction time，the yield stress decreases first and then increases with the increase of temperature；When the yield stress is the lowest，the corresponding reaction temperature of slurry is 10 ℃；The best temperature for the preparation and transportation of the slurry is 10 ℃，at this time，the material resistance loss coefficient of slurry is the smallest.According to the results of this study，when the mine uses high-concentration full tailings filling slurry，the filling temperature can be adjusted appropriately to make the filling slurry reach the optimal state of rheological properties，thereby reducing the occurrence of pipe blockage accidents with the filling slurry.
In recent years，the state has strict requirements on the safety production of mining enterprises.The safety problem has become one of the most important problems of each mining enterprise.Tailings pond is an indispensable part in the production process of mining enterprises，so the safety of tailing pond is closely connected with the local development.The dam break of tailing pond will cause great loss and serious damage to local environment and economic development，and even endanger people’s lives.By evaluating the safety of tailings pond reasonably，the safety accident of tailings pond can be avoided effectively，so as to ensure the normal safety production of mining enterprises.The evaluation of tailings ponds is characterized by uncertainty，complexity and variability，and there are many indexes factors affecting the safety of tailings ponds.The information conveyed by most of the influencing factors is of significant uncertainty and randomness，which makes the safety evaluation of tailings ponds a complex and changeable problem filled with many uncertain factors.Aiming at the problem of uncertainty in safety evaluation of tailings pond，the theory of unascertained measure was introduced to analyze the relationship between the evaluation object and the evaluation indexes.Taking the Huangjindong tailings pond as an example，by selecting 18 influencing factors，a comprehensive safety index evaluation system of tailings pond containing 5 types of influencing factors and 18 influencing factors was established.The comprehensive weight of indexes was determined by combining the analytic hierarchy process（AHP）-entropy weight method，and an unascertained measure model based on the improved entropy weight method was constructed.By quantifying qualitative factors，this model eliminates the differences among factors，improves the problem that the subjective and objective weights have small differences and cause the evaluation results to change greatly，and weakens the influence of weight values on the evaluation results.At the same time，the index measure function is determined according to the index evaluation system and classification mode of the model，and the measured value of each index is substituted into it to obtain the comprehensive measure vector of multiple indexes，and the safety level of tailings pond and the importance of unascertained measure of each index are accurately determined by the confidence recognition criterion.Results show that the security level of Huangjindong gold tailings is Ⅱ level，means the tailings is in a safe state.By comparing，the importance level of indicator measure from high to low is foundation subsidence（B3），flood top（B1），safety management（B4），dam break（B2），natural factor（B5）.That means foundation subsidence has the greatest impact on the safety of tailing pond，it is necessary to strengthen management of ground subsidence.The evaluation results based on the improved entropy weight method-unascertained measure model are consistent with the actual results，which provides a feasible method for the safety evaluation of tailings pond.
Silicon malachite is an extremely refractory copper oxide mineral，and the focus of chrysocolla flotation research is the development of new reagents.However， the selectivity and price factors of new pharmaceuticals restrict their industrial applications.In order to improve the flotation index under the premise of using conventional flotation reagents， it is very important to conduct process mineralogy research on refractory copper oxide ore.A refractory gold-copper oxide ores in Gansu Province contains Au 4.83 g/t and Cu 1.18%. The oxidation rate of Cu is as high as 95.87%.The copper minerals are mainly chrysocolla， which is difficult to select and closely related to gangue minerals.Gold is associated with copper minerals.Based on the study of mineralogy of raw ore process， the causes of copper and gold losses in tailings were analyzed and discussed.Sulfide flotation was adopted.After grinding，the products with fineness less than 74 μm accounted for 80%.Under the conditions of sodium sulfide as curing reagent， copper sulfate as activator， butyl xanthate， hydroxamic acid and No.25 dithiophosphate as collector， the sulfide flotation process adopted is “roughing once，sweeping four times，and regrinding coarse concentrate for three times”.The results show that the gold-copper concentrate with Au grade of 86.65 g/t， Au recovery rate of 89.11%， Cu grade of 16.93%， Cu recovery rate of 71.92%，Ag grade of 216.24 g/t and Ag recovery rate of 87.26% was obtained.Through analysis，it is believed that there are 4 reasons for the loss of copper and gold in tailings.1）The oxidation rate of copper is high， there are many types of copper minerals，and there are differences in floatability，in addition，silicon malachite is the main copper-bearing mineral， and its floatability is not good.2）There is a phenomenon that fine-grained silicon malachite is wrapped in gangue minerals.3） The tailings screening analysis shows that the copper lost in the tailings is of fine grade，therefore， the loss of this part of copper in the tailings is a reasonable loss.4）The gold phase analysis results show that the distribution rate of silicate-coated gold and carbonate-coated gold in the tailings is 76.38%， and the gold lost in the tailings is mainly wrapped in veins stone minerals.Gold-copper concentrates can be pre-oxidized by hot-pressing and non-cyanide to recover gold and copper.This smelting process can provide a certain reference for the development and utilization of gold-copper oxide copper mine.
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