Mining activities result in both geological hazards (e. g. ,ground subsidence,infrastructure damages,etc. ) and environmental hazards (e. g. ,soil degradation,ecosystem degradation,etc. ) across the mining areas. The types and features of mining-induced hazards are controlled by the mining methods,and the occurrence of multiple geo-environmental hazards are coupled with each other like a chain or net. Three methods are usually adopted to deal with the overburden rock above the deposit during the mining activities:letting the overburden cave in freely without support,leaving mineral pillars to support the overburden,and stripping and moving away the overburden,which leads to the formations of longwall mining goaf,partial mining goaf and open pit goaf,respectively. This paper summarized the mechanism of geo-environmental hazards of these three kinds of goafs. The formation mechanism of disaster chain induced by multi-coupled geo-environmental hazards is discussed. Then the existing problems in geo-environmental monitoring and mining-induced disaster chain studying are analyzed. The results show that:① The geo-environmental hazards in mining areas mainly consist of engineering disaster and ecological environmental disaster. The former is manifested as the damages of engineering structures caused by the additional mining stress that induced by the changes in spatial positions of ground objects,while the latter is reflected in the loss of ecological components and the changes in energy and material flow that induced by the property changes of land objects. ② As different geo-environmental hazards are coupled,a geo-environmental disaster may lead to a series of secondary disasters and finally forming a disaster net. Although the deformation monitoring techniques,remote sensing techniques,etc. can be used to obtain the locations and properties of ground objects,but the complexity of geo-environmental hazard formation and the shortages of a single monitoring or forecasting technique make it hard to provide an accurate forecasting of geo-environmental disasters. ③ To better fuse multi-source geo-environmental data and detect physical environment field of mining area,an integrated " space-air-buildingground- mine-human" monitoring system should be established by integrating various deformation monitoring,remote sensing, engineering inspection and other techniques. On this basis,the prospects for future work are developed under an interdisciplinary perspective:① The effort on multi-source data standardization and data security sharing should be strengthened,and a knowledge database about geo-environment protection should be established. ② With the help of AI techniques and the knowledge database of geo-environment protection,the geo-environmental disaster net should be established by studying the coupling mechanism of multiple geo-environmental hazards and revealing the key factors of disasters. ③ More interdisciplinary researches should be conducted based on the geo-environmental disaster net,and by fusing muti-source data-models,a whole-process workflow including “transparent geological conditions-mine design-mining damage/ physical field evaluations-engineering and environmental evaluations-engineering reinforcement/ environment restoration” should be established. The analysis results are helpful to further organize the research approach for the multi-disaster coupling issues in mining areas and have good reference significance for the comprehensive protection and management of geo-environmental disasters.

The water sand filling method was used in the early stage of a subsequent filling mine,and the water secretion effect of the filling body was poor,and the filling body was rich in water. With the increase of water-sand filling area,the stability of roof and hanging wall of the stope becomes worse. In order to improve the mining safety,the mining enterprise adopt the cemented filling method. Therefore,it is urgent to set isolated pillar between water sand filling body and cemented filling body to ensure the safety of subsequent mining activities. In this study,the theoretical analysis model of side wall pressure inclined pillar is constructed,and the hydrostatic pressure gradient of 10~ 15 m width water sand-cemented filling isolated pillar and different water sand filling bodies is studied by FLAC 3D numerical simulation software. The study results show that:① Mining disturbance will cause stress concentration in the isolated pillar,and the non-solidified water sand filling body will further increase the maximum principal stress in the pillar. ② The redistribution of the stress of the pillar and the horizontal pressure of the water sand filling body increases the horizontal displacement of the pillar,and gradually produce damage and form a plastic zone. The 10~ 13 m isolated pillar is not enough to support the stability of the stope under the water bearing condition of the filling body. ③ Considering the influence of blasting disturbance,in the case of existing water rich backfill,the recommended isolated pillar width is 15 m. ④ When the width of isolated pillar is 15 m,with the increase of hydrostatic pressure gradient,the maximum principal stress and displacement in the pillar increase slightly,and the plastic zone does not increase significantly,indicating that the 15 m isolated pillar can ensure the safety of the stope in the mining process.

Underground mining is the main way of metal mining. In the long-term mining process,the goaf and unstable areas formed need to be filled and grouted. In view of the stability evaluation of Xinli mining area of Sanshandao Gold Mine after treatment,firstly,the whole process stability of the mining area after mining and treatment is analyzed through numerical simulation. Secondly,analytic hierarchy process is used to determine the weight of many factors affecting the stability of rock mass,and the factors with greater influence are obtained as the evaluation index of D-S evidence theory to evaluate the stability of rock mass after governance. The results show that the overall deformation increases slowly after treatment,the deformation of plastic zone is in a stable state,and the filling treatment effect is good,reaching the expected effect. The treatment situation and the mechanical state of surrounding rock after treatment have the greatest impact on the stability of rock mass,followed by the stability before treatment,and the geological factors have the least impact. In the factor layer,the gob control rate has the greatest impact. D-S evidence theory proves that all levels are stable after treatment,of which -165 m level is relatively poor,followed by -240 m level.

The safety control method of the wedge-shaped transition from open-pit to underground mining is to use the surface collapse pit formed by caving the hanging wall to prevent the slope rock movement from threatening the open-pit. However, it is difficult to control the failure process of high and steep slope under ground mining disturbance,which restricts the application of wedge transfer mode in large-scale deep concave open-pit mine. In order to solve the above problems,combined with the limit equilibrium analysis method,the law of progressive failure of high and steep slope under the disturbance of caving mining is revealed,and the calculation method of slope sliding body volume is proposed. Finally,the rock displacement hazard control technology of slope is developed. This technology can control the slope sliding process to make the collapse pit fully accommodate the slope sliding body through regulating the mining sequence. The research shows that the slope will not be continuously damaged with the downward mining of the hanging wall ore. Only when the hanging wall ore is mined to the key section, because the rock mass stress state exceeds the limit equilibrium state,the slope slip failure occurs. The slope slip can be delayed by delaying the stoping of the triangle mine on the hanging wall of the key sublevel,and the volume of the collapse pit can be increased by delaying the stoping of the foot ore body of the key sublevel and using the down-stepped stoping face,so that the collapse pit can receive the sliding body of the slope in an orderly way. The research results improve the applicability of the wedge-shaped transition mode in large deep concave open-pit mines by improving the safety control method.

Identifying the spatial distribution characteristics of old goaf is essential to prevent and control of surface collapse disaster of goaf. Aiming at the problem that the existing detection accuracy is still difficult to meet the needs of goaf management, a detailed detection method of goaf is proposed,that is,high precision magnetic method detecting the plane range of goaf,natural source surface wave method and controlled source audio magneto telluric method measuring the position of goaf, exploration drilling modifying the detection results. Taking Dunqiu Iron Mine as an engineering background,high precision magnetic method is used to detect the characteristics of magnetic field,and the plane distribution range of old goaf is delineated. Further,natural source surface wave method and controlled source audio magneto telluric method are used to measure the strata section,the resistivity and wave velocity of rock in different positions are obtained,the vertical distribution range and depth of goaf are inferred,which are contrasted and modified according to the results of exploration drilling finally. The detailed detection on spatial distribution of goaf in iron mine is realized. The plane shape of goaf formed by the mining of No. 2 orebody group is approximately crooked gourd shape,with an area of 4 992. 5 m2. The goaf can be divided into pure goaf and backfill goaf. The goaf volume of No. 2 orebody group is 112 281. 33 m3,which is calculated by the average thickness method. The detection results are in good agreement with the basic mining data,and the research methods and results have certain guiding significance for the detection and treatment of old goaf in iron mine.

It is an important means to improve production efficiency and ensure production safety to formulate an effective scheduling strategy of trackless transport vehicles in an underground mine. Aiming at the characteristics of the trackless transportation in underground mine,such as the complex road conditions and difficult vehicle avoidance,etc. ,the influence of underground roadway structure on transportation capacity is analyzed. On the basis of acquiring real-time position and loading information of underground vehicles,the right-of-way priority principle of underground trackless transport vehicle under different route structure is determined. For the goal of minimizing the total transport work and the vehicle waiting time,the objective optimization model of underground trackless transport vehicle scheduling based on GA algorithm and logical relationship is constructed. The actual running data of a underground trackless vehicle in a certain mine is used to solve the established objective optimization model,the results show that:① The established right-of-way priority principle can effectively reduce the probability of vehicles meeting in the non-wrong section and thus cause safety accidents,and improve the efficiency of vehicle operation; ② Taking the actual operation data of the case mine as the basic parameters,GA algorithm is used to solve the objective function established for calculating the total transport work,and the optimal path scheme with the minimum total transport work of 2 399. 21 t·km was obtained when the total transport volume is of 4 730 t/ d;③ On the basis of the minimum transport work per day,the vehicle waiting time of different scheduling schemes is solved via logical relations,and the specific transport route and running time of vehicles are obtained. this provides the best vehicle scheduling scheme for mine production scheduling, which is conducive to reducing transport costs and improving vehicle operating efficiency.

The identification and study of crack initiation stresses are of great importance for understanding the load deformation and damage processes in brittle rocks. This paper systematically summarizes the existing methods for determining crack initiation stress (crack volume strain method,lateral strain method,moving point method,acoustic emission ringing counting method) and their problems,and proposes a method for evaluating crack initiation stress in brittle rocks based on the evolution of acoustic emission b-value. A series of uniaxial loading tests on meta-gabbro and granite were carried out using the GAW2000 uniaxial rigidity testing machine and acoustic emission tester,and the proposed and existing methods were evaluated based on the mechanical and acoustic emission results. The results show that the acoustic emission b-value evolution method has a clear physical mechanism and meaning,can easily and accurately determine the magnitude of the initiation stress,and the measured stress results are consistent with those obtained by the existing methods. The analysis of variance shows that there is no statistical difference between the proposed method and the existing method,which verifies the reliability of the method in determining the crack initiation stress. The crack initiation stresses of both rock samples were positively and linearly correlated with the uniaxial compressive strength,and the crack initiation stresses determined using the proposed method were about 0. 51 times of the uniaxial compressive strength for meta-gabbro and 0. 48 times of the uniaxial compressive strength for granite. The proposed method and its findings are valuable for enriching the means of rock crack initiation stress testing and exploring the mechanism of brittle rock damage.

During the excavation of water-rich bedrock by artificial freezing method,the bonding surface between artificial underground ice and rock mass is often affected by dynamic impact,and its stability determines the safety of underground engineering construction. In order to study the dynamic mechanical properties of ice-rock composite structure,the loading system of SHPB was constructed by PFC-FLAC coupling method. The dynamic characteristics and failure characteristics of ice-rock composite were analyzed,and the evolution law of microcracks was studied. The results show that the dynamic elastic modulus of the composite specimen is less affected by the inclination angle θ of the ice-rock interface. Under the action of dynamic load, the crack in the rock of the composite specimen gradually expands from the incident end to the ice-rock interface,and finally forms a penetrating main crack parallel to the loading direction. The propagation of micro-cracks 'guides' the damage process of the composite. The final failure mode of the composite specimen is tensile and shear composite failure,and the failure characteristics of the rock part are mainly affected by the dip angle of the interface. When the dip angle of the ice-rock interface θ is 0°~45°,the peak stress has little difference,while the peak stress increases with the increase of θ,in the value ranges from 45° to 90°

The traditional cumulative deformation prediction methods are diverse in curve structure decomposition methods and characterization model selection,which brings about the problems of large workload of prediction methods,low prediction accuracy,and restricted applicability objects. To address the above problems,a multivariate self-optimizing dynamic neural network is established based on a nonlinear autoregressive model considering the effects of rainfall,reservoir water level and reservoir water level changes on the cumulative deformation of landslides. The neural network is applied to the prediction of the cumulative displacement of the typical stepped landslide in the Baijiabao landslide of the Three Gorges Reservoir. By analyzing the time series of the cumulative curve of landslide deformation,a nonlinear autoregressive neural network is composed by using a neural network to solve the full curve model. The parameters and structure of the neural network are optimized and trained using multiple swarm genetic algorithms,and the mean square error of the fitness function is used as the prediction model error deviation criterion. The results show that the self-optimized dynamic neural network proposed in this paper has high accuracy in fitting the cumulative displacement of multiple measurement points of landslides. Its error can be controlled within 1%,and the prediction process reduces the error caused by subjective factors. The neural network can provide a reference for the prediction of cumulative displacement of such step-type landslides.

In view of the loss of micro-fine iron minerals with a particle size of less than 20 μm in Donganshan high-intensity magnetic tailings,this paper studied the selective agglomeration effect of different types of starch and its modified products on micro-fine hematite,and determined the best agglomeration agent and dosage by agglomeration-magnetic separation test. The morphological characteristics of the agglomerates before and after the agglomeration of the reagent with hematite and quartz were detected by means of polarizing microscope and FTIR. The mechanism of the action of the polymer reagent was studied,and the selectivity and agglomeration effect of the polymer reagent were clarified. The test results showed that when the dosage of reagent is 200 g/ t,the beneficiation index of cross-linked corn starch is better than that of other reagents. The addition of agglomeration reagent can realize the selective agglomeration of micro-fine hematite,which increases the recovery rate of iron concentrate by 2. 13~3. 94 percentage points and the beneficiation efficiency by 2. 77~3. 46 percentage points. However, due to the irregular flocculation of hematite after agglomeration,a small amount of quartz will be mixed in the larger agglomeration, resulting in a slight decrease in the iron grade of magnetic separation concentrate.

The medium-poor oxidized ore in Bayan Obo deposited for many years contains iron,rare earth and other composition, which is difficult to be separated efficiently by conventional process,but the iron can be recovered efficiently by hydrogen- based ore phase transformation-magnetic separation process. In order to understand whether the phase conversion process of hydrogen-based ore affects the floatability of rare earth minerals in rare-earth-rich iron tailings,a systematic beneficiation test was carried out. The results showed that under the conditions of 506E dosage of 4 200 g/ t,sodium silicate dosage of 1 800 g/ t and slurry temperature of 65 ℃,the closed circuit flotation with two roughing and three cleaning achieved a rare earth ore concentrate with an REO grade of 59. 00% and an REO recovery of 67. 91%. Chemical composition analysis and X-ray diffraction showed that the main components were rare earth oxides (Ce7O12),monazite and a small amount of fluorite. The rare earth elements were effectively enriched in the concentrate,demonstrating that the hydrogen-based mineral phase transformation process did not adversely affect the flotation recovery of rare earth elements.

The iron grade of iron ore in Xudonggou and Yabaleng mining areas in Anshan region is 29. 50%. The main iron minerals is magnetite,and the main gangue mineral is quartz. In order to develop and utilize the ore efficiently,based on the ore properties analysis obtained by X-ray fluorescence analysis,chemical composition analysis,iron phase detection and scanning electron microscope,the selection conditions of wet coarse medium magnetic preconcentration,stage grinding stage weak magnetic separation,elutriation machine cleaning and extended continuous separation test were carried out. The results showed that:① the iron grade and recovery rate of magnetic pre-selected coarse concentrate in the drum magnetic separator of -2. 5 mm high pressure roller grinding products are 40. 20% and 89. 76%;② After two stages of grinding (the fineness of the first and second stages of grinding is -0. 074 mm accounting for 75% and -0. 045 mm accounting for 90%,respectively),three stages of low intensity magnetic separation,and one stage of washing machine selection,the iron concentrate with final yield of 35. 73%,iron grade of 67. 08%,iron recovery of 81. 24% was obtained,and iron grade of tailings is only 8. 61%. The research results can be used as the basis for development and utilization of the ore.

The zinc and tin grade of a carbon-containing high-sulfur zinc tin ore in Inner Mongolia are 1. 02% and 0. 86%,and the content of sulfur and carbon are 14. 02% and 1. 68%,respectively. The mineral composition of the ore is more complex. The main useful minerals are sphalerite,cassiterite and pyrite,and the gangue minerals are mainly quartz,chlorite and sericite. In order to determine the rational development and utilization technology of ore,the beneficiation experiment was carried out by the pre-decarburization and flotation-gravity combined process. The results showed that zinc concentrates with Zn grade of 45. 16% and Zn recovery rate of 71. 19% and sulfur concentrates with S grade of 46. 92% and S recovery rate of 81. 91% could be obtained through pre-decarbonization,mixing flotation of one roughing,one scavenging and one cleaning for zinc and sulfur,and separation and flotation of one roughing,one scavenging and three cleaning for zinc and sulfur. The flotation tailings are reselected by shaking table,and after rough selection,cleaning selection,check and middling reselection,the tin concentrate with Sn grade of 45. 52% and Sn recovery rate of 81. 99%,and the tin rich middling ore with Sn grade of 3. 13% and Sn recovery rate of 11. 09% could be obtained. The designed test process solves the adverse effect of organic carbon in ore on flotation,recovers valuable minerals comprehensively,and can provide theoretical reference for the development and utilization of similar ores.

Aiming at the problem of excessive copper and lead content in molybdenum concentrate of a large porphyry molybdenum mine in Heilongjiang,the beneficiation optimization test was conducted based on the process mineralogy. The test result showed that the molybdenum concentrate assaying Mo of 54. 32%,Mo recovery rate of 90. 69%,Cu of 0. 048%,Pb of 0. 062% was obtained by using flowsheet of coarse grinding,Mo step flotation,Mo-Cu bulk flotation,Mo-Cu bulk concentrate regrinding and separation of Cu-Mo combined with the self-developed effective molybdenum collector PM for the ores assaying Mo of 0. 122%. Compared to the original process,the copper content in the molybdenum concentrate obtained by the new process had been decreased by 0. 322 percentage points and the lead content had been decreased by 0. 348 percentage points. The process successfully reduced the impurity content of copper and lead in molybdenum concentrate. The research results can provide a basis for the development and utilization of the ore.

This study investigates a novel low-temperature roasting and non-acid leaching lithium extraction process using a new roasting aid,ASH,for an extremely low-grade clay lithium ore in Yunnan,China,with a lithium content of 0. 147%. The reaction mechanism was elucidated through X-ray Diffraction (XRD),Scanning Electron Microscopy with Energy Dispersive Xray Spectroscopy (SEM-EDS),and other analysis methods. Experimental results demonstrated that under the conditions of a sample to ASH mass ratio of 1∶0. 3,roasting temperature at 400 ℃,roasting time of 1. 0 hour,deionized water as the leaching agent,leaching time of 2 hours,leaching temperature of 70 ℃,and liquid-solid ratio of 5 mL/ g,the lithium leaching rate reached 83. 81%. Mechanism analysis indicated that while the main mineral phases in the sample remained unchanged before and after roasting-leaching,the intensity of diffraction peaks decreased. Post roasting-leaching,the sample surface exhibited uniform distribution of cracks and voids,along with decreased contents of Al,Si,Fe and Ti. This suggests a reaction between ASH and minerals,disrupting the mineral surface structure and generating soluble Li-ASH leachate. Compared to traditional roasting-leaching processes,this study′s lithium extraction process features lower roasting temperatures and acid-free leaching, reducing production energy consumption,simplifying the process flow,and offering significant insights for the green and efficient development and utilization of similar low-grade clay lithium ores.

Phosphogypsum is a solid waste generated by the wet process phosphoric acid process. Aiming at the problems of poor quality,low whiteness,and hardly utilization of phosphogypsum,systematic process mineralogy research by multiple analysis methods including XRD,SEM and micro morphology for a phosphogypsum in Hubei were conducted. Based on which, improving purification removing impurities experiments was conducted. The results indicated that the main mineral composition of the tested phosphogypsum is calcium sulfate dihydrate with main gangue mineral of quartz,meanwhile the small amount of carbon particles,organic matter and water-soluble phosphorus and fluorine is also existed. With the usage of 800 g/ t of kerosene and 10 g/ t of 2# oil for carbon removal,100 g/ t of 1231 and 300 g/ t of MIBC for silicates removal,a full process of "double reverse flotation,regrinding and reselection" could be used for obtaining good indicators of phosphogypsum concentrate with 97. 28% purity and 58. 15% whiteness. The indexes is better and purity and impurity content of phosphogypsum concentrate all meet the first class product in Chinese national standard. The success of the experiment points out the direction for large-scale and high value-added utilization of phosphogypsum solid waste.

Due to the changes in the composition of Jinchuan nickel raw materials,the copper content of high-nickel matte is elevated,which changes the equilibrium state of the milling and flotation system,resulting in higher metal intercontainment in the secondary copper and nickel concentrates. The quality of flotation products depends on the size and mosaic relationship between nickel and copper mineral crystals,while the crystals size and mosaic relationship is affected by heat preservation and slow cooling conditions. Therefore,it is urgent to investigate the influence of heat preservation and slow cooling conditions on the flotation behavior of minerals in high nickel matte. The results showed that under the appropriate slow cooling and temperature control conditions,a copper concentrate with 53. 9% Cu grade and 86. 1% Cu recovery and a nickel concentrate with 66. 2% Ni grade and 81. 5% Ni recovery can be obtained by 1 roughing test. Compared with the test results of the field samples, the flotation effect of high nickel matte was improved. The mechanism study showed that the flotation effect was better than that of the original sample because of the increase in the grain size and monomer dissociation of pyrochlore in the sample after controlled temperature and slow cooling.

With the full use of electronic detonators in open-pit mine bench blasting,the millisecond blasting technology has been further developed. How to improve the interaction force between blast holes by adjusting the delay between holes has become the focus of mine blasting technology research. Based on the concrete model to simulate the millisecond blasting in open-pit mines,a high-speed photography technology and digital image correlation (DIC) test system were established. Based on the full-field micro-strain,high-speed photography technology and numerical simulation,the development process of cracks between blast holes under different inter-hole delay conditions was studied. The results show that the strain duration near the surface crack of the model under explosion load is about 3 ms. When the delay between holes is 3 ms,the next hole initiation can improve the interaction force between holes. The pressure distribution characteristics of the measuring points are shown by numerical simulation. The pressure of the measuring points is the largest when the inter-hole delay is 3 ms,which verifies the accuracy of the model test. Using MATLAB to analyze the numerical simulation results,it is found that the degree of fragmentation is the best when the delay time between holes is 3 ms,which is in good agreement with the model test results. The use of high-speed photography technology combined with digital DIC method provides a new idea for studying the interaction force and crack propagation between blast holes.

Blasting parameters of trenching are the key parameters of the construction of rock tunnel drilling and blasting method,and optimization of blasting parameters is one of the important ways to ensure the efficient construction of drilling and blasting method. Based on 200 representative blasting cases,this paper analyzes the change characteristics of blasting parameters in two dimensions of rock tunnel characteristic parameters,namely Pratt′s coefficient and cross-sectional area,by using statistical methods to study the objective law of rock tunnel trenching by constructing a database of blasting cases. The results show that:with the increase of Pratt′s coefficient,the ultimate compressive strength of the rock is greater,and the length of the blast hole and the unit consumption of explosives will be increased appropriately to ensure the blasting effect,and the single cycle feed will also be slightly increased,but the high stress of the rock itself causes the clamping process to reduce the utilization rate of the blast hole. Usually the empty hole is set to provide a new free surface for the trenching blasting,and the reflected stretching of the stress wave makes the rock body near the free surface. The damage area is larger,and hard rock passages are more suitable for straight-hole trenching. In the process of trenching and blasting in larger section rock tunnel,the rock itself is less entrapped,and good blasting effect can be achieved with less explosive consumption,thus promoting the improvement of single-cycle feed and utilization rate of shell holes. Because the limiting effect of large section area on rock blasting is reduced, it is not necessary to increase the number of shell holes and charge excessively,instead,the growth rate of the number of shell holes can be slowed down appropriately to achieve good blasting effect. The effect of blasting can be achieved by slowing down the growth rate of the number of holes. This study provides theoretical guidance for optimizing blasting parameters and efficient construction of rock tunnel.

In order to study the interaction mechanism of explosive cracks between adjacent holes under explosive load, a new digital laser dynamic caustic line experiment system was used to study the mechanism of explosive cracks growing each other under different spacing and different charge structure by changing the spacing of holes and adjusting the structure of charge package. The results show that the explosive cracks in the two holes are randomly distributed in the case of the ordinary drug package,and the explosive cracks expand independently in the early stage when the slit drug package interacts with the ordinary drug package,and attract each other as a free surface in the later stage. When the two holes are interacted with slit charge,the explosion-induced cracks are distributed in a "straight line" in the direction of the central axis of the holes. When the spacing is large,the crack distribution in the direction of the central axis of the gun hole is "hand-in-hand". With the increase of hole spacing,the energy loss of crack encounter is larger,the peak value of dynamic stress intensity factor and crack velocity are smaller,and the amplitude is lower. The area of crushing zone formed around the hole and the length of secondary crack are smaller,and the fractal dimension is smaller.

In order to study the characteristics of ore-controlling fault activities and ore-controlling laws in uranium mines to guide mineral exploration in northern Guangdong Province,the Nanxiong Fault Belt in the northern Margin of the Nanxiong Basin is taken as the research object,and the characteristics of the Nanxiong Fault Belt activities and the prospecting regularity of uranium mines have been discussed through researches on field geological sections,LA-ICP-MS zircon U-Pb chronology and characteristics of microstructural deformation. The research results show that the features on tectonic deformation of the Nanxiong Fault Belt in Triassic are mainly ductile deformation,and the post-magmatic hydrothermal quartz veins and felsic dikes in the Late Triassic cut through granitic mylonite and mylonite granite. Their weighted average ages of zircon U-Pb isotopic analysis are respectively (230. 2±1. 7) Ma,(228. 9±5. 8) Ma and (210. 0±2. 1) Ma. The microstructural characteristics of granitic mylonite and mylonite granite in the Nanxiong Fault Belt have show typical ductile deformation phenomenons with "S-C" fabric, elongation and dynamic recrystallization of quartz,"σ" type rotational fragmentation of quartz and book oblique structure of plagioclase feldspar. These characteristics of microstructural movement mainly present left-row shear in the direction of ductile deformation. In Triassic,two stages of elevated-temperature deformation and medium-low temperature deformation have been revealed. It is considered that these areas of 210 Ma ductile deformation in Nanxiong Fault Belt do not have the conditions of oreforming mechanism of critical transformation for precipitation of uranium mines. These is a inferential conclusion that the areas,in which the granites experienced strong ductile deformation in 125~120 Ma and 110~105 Ma,regional extensional movement of the same period and had been accompanied by intrusion of mafic dykes and uranium mineralization,can become metallogenic prospective areas of uranium mineralization or depositing uranium mines. This analysis results provide new ideas about appraisement of uranium mines and feasible prospecting for further improving the uranium resources in the integrated exploration area of southern Zhuguang Mountain.

Rapid and accurate analysis of surface deformation characteristics and accurate prediction of deformation trends in open-pit mines is an important guarantee for promoting green and safe production in mines. Aiming at the problems of the current deformation monitoring techniques,such as low temporal and spatial sampling rate,high cost,and difficult to determine the parameters of prediction model,an integrated method of slope stability analysis and deformation prediction based on short baseline subset interferometry (SBAS-InSAR) technique and COMSOL finite element simulation was proposed by taking East Anshan Open-pit Iron Mine as the engineering background. Firstly,62 views of Sentinel-1A up-orbit SAR data acquired from May 2018 to June 2020 were processed by SBAS-InSAR technology. The time series of surface deformation in the region within 2 years could be acquired and the temporal and spatial evolution characteristics of the deformation,and the spatial and temporal evolution characteristics of the deformation were analyzed. Then,COMSOL software was used to simulate the slope stability condition of a typical subsidence area under the influence of external heavy rainfall. The damage cracking law and deformation mechanism of the slope were explored. Based on this,the particle swarm algorithm (PSO) was adopted to optimize the long-short-term time memory (LSTM) network to build an optimal model for deformation time series prediction and to carry out deformation time series prediction within the typical settlement area. The average absolute error and root mean square error were introduced as the evaluation indexes of prediction accuracy. The results show that the subsidence in the western part of the mining area is relatively serious,and the average annual subsidence rate is as high as 47. 8 mm/ a. There is a significant correlation between the deformation rate and the quantity of local rainfall. Compared with the traditional deformation prediction model, the two errors of PSO-LSTM model are reduced by at least 14% and 36% respectively. It can effectively reflect the fluctuation trend of surface deformation in the mining area,which provides a potential approach for early warning of landslides.

At present,China′s oil and gas resources are mainly transported in the form of buried pipelines. The surface movement and deformation caused by mining when crossing goaf will inevitably have a certain impact and harm on the buried oil and gas pipelines. The Jining Branch Pipeline of the Shandong-Anhui Pipeline passes through Dongtan Coal Mine of Yankuang Energy Group Company Limited,and the nearest horizontal distance from the 3308 working face in mining area 3 is only 85 m. In order to ensure the safety of the Jining Branch Pipeline of the Shandong-Anhui Pipeline and realize the safe and efficient mining of the 3308 working face,a monitoring and evaluation method for shallow buried oil and gas pipelines and surface deformation is proposed. Based on the actual measurement of surface movement and deformation of the 3308 working face and the monitoring data for pipeline stress,the characteristics of surface deformation along the Jining Branch Pipeline of the Shandong-Anhui Pipeline and its impact on the pipeline are studied,and the changes of pipeline monitoring stress under the influence of mining are analyzed. On this basis,the current risk of buried pipelines affected by mining is evaluated,and the pipeline protection measures are proposed. The results show that the surface subsidence and slope deformation caused by the mining of 3308 working face have little impact on the pipeline deformation,and the current stability level of the surface along the pipeline is Grade Ⅳ,with low risk. The surface movement and deformation have a certain impact on the stress state of the pipeline, especially the initial mining area is close to the pipeline,and the surface along the pipeline is more active,leading to the increase of the axial stress of the pipeline. A certain period of stress monitoring practice was carried out for the pipeline,and the monitoring results were lower than the third level threshold value of the pipeline early warning specification. The pipeline operation was always in a green and risk-free range. In the future,measures should be continued to be taken to monitor the deformation and daily protection of the goaf site and buried oil and gas pipelines. The study results have certain reference significance for safe and efficient coal mining under buried oil and gas pipelines.

Driven by the transformation of digital production in metal mines,how to carry out detailed production simulation for digital twins from the perspective of future production prediction to improve the overall production efficiency has become an urgent problem to be solved. Aiming at the scheduling requirements of high accuracy,strong operability and good foresight, the digital twin system architecture of open-pit metal mine is constructed,and the application path of mine digital twin based on production simulation test is expounded. Combined with the analysis method of Job shop scheduling problem (JSSP), the objective function of shoveling equipment flow scheduling simulation was constructed based on the PT maximum of total cycle output and PM maximum of average output per unit,and the simulation test flow was designed including the construction of simulation model,testing model error,designing simulation test and analyzing test results. Finally,taking the fifth year production plan of an iron mine in Panxi as an example,based on the objective function,the simulation and prediction calculation of the stope transport and the whole process transport are carried out,and a total of 515 test schemes are calculated. The absolute value of calculation error of the model is controlled within 2%. Considering the balance among data such as production capacity, equipment load and equipment work efficiency,device scheme 480 and 229 are recommended as the optimal schemes. The results show that the designed simulation test flow and model prediction results are reliable,which can realize the multi-angle evaluation of scheduling schemes,and can provide a basis for the innovative application of large-scale continuous production system simulation.

The operation of underground mines is dangerous and the spatial topology is complex,so mine safety accidents often occur. Reasonable emergency evacuation path planning and evacuation instructions can effectively improve the escape efficiency of underground personnel and reduce casualties and property losses. Combined with an example of an underground mine,an underground mine roadway network model is built based on space syntax and GIS network analysis. From the perspective of spatial cognition of escape personnel,the foreground network and background network in the roadway network model are selected as the main avoidance points by using the standardized angle choice degree. It provides a reference for the layout of emergency evacuation indicators. Considering the basic roadway attribute information such as roadway width,roadway type and roadway slope,and combined with the space syntax index (standardized angle integration degree),an emergency vulnerability model of roadway network is constructed. Considering the stability of roadway spatial units,the optimal cognitive path of underground personnel is planned,and multi-objective emergency evacuation route planning of underground mine is realized. This research can not only provide suggestions for the design of tunnel layout in underground mines,but also assist decision-making for emergency evacuation path planning in underground mines,provide theoretical basis for the formulation of emergency plans,and provide new ideas for the construction of emergency hedging systems.

At present,the traditional belt conveyor inspection method mainly relies on manual inspection,which has some problems such as high labor cost,low efficiency,easy to make mistakes and missing inspection. Therefore,an automatic detection method of mine belt conveyor based on mobile robot is proposed. Mobile robot is used to inspect along the belt conveyor, and the belt conveyor is automatically detected by the mounted sensor and camera,and the information including RGB images required by maintenance inspectors is collected. The automatic detection method of mobile robot is divided into four key parts, including determining the detection target and parameters,designing the sensor and data processing system of mobile robot,developing the detection path and strategy,and real-time monitoring and alarm processing. According to this,the automatic detection process of mine belt conveyor is divided into three steps:automatic navigation of mobile robot,automatic detection of mobile robot and data upload. The automatic navigation function and fault detection efficiency of mobile robot are tested in simulated mine production environment. The results show that the proposed method is helpful to detect the belt conveyor state efficiently and accurately,and alarm in time when abnormal conditions are detected,which provides certain technical support for ensuring the safety of mine production.

According to the characteristics of low transmission efficiency and poor sharing of mine safety production testing data,comprehensive consideration of development cost and working environment requirements,Based on CAN (Controller Area Network) and REST (Representational State Transfer) Internet of Things technqiues,this paper proposes an intelligent mine safety monitoring method,and designs a mine safety detection and discrimination program. The data information early warning program is developed by using the maximum entropy model algorithm. Combined with CAN bus technology,the multisensor information is organically integrated and safety data detection is carried out,and the relevant information of downhole sensor equipment is transmitted to the switchboard after judgment and analysis. The proposed safety monitoring method is developed systematically and applied in a mine in Huaibei. The results show that the safety detection method based on CAN and REST Internet of Things techniques can realize multi-point measurement,and can immediately increase or decrease the detection equipment,and can realize real-time data transmission and sharing,which is conducive to realizing real-time mine safety detection.

Low-quality image enhancement is an important part of the perception system of unmanned wide-body vehicle in open-pit mine. The image acquired by monocular camera is susceptible to many factors such as dust,rain,snow and fog in mining area and violent vibration. Aiming at the problems of high noise and color distortion in the traditional image enhancement algorithm,an improved Retinex-Net algorithm is proposed to enhance the image of open-pit mine. Cyclic adversarial generation network and two-channel residual network are used to improve the enhancement and denoising parts. The cyclic adversarial generation network generates more natural and realistic enhanced results by learning the mapping relationship between low-light and normal-light images. The dual-channel residual network can effectively remove noise and artifacts in low-light images by processing brightness and chrominance information simultaneously. The experimental results show that the proposed method is superior to the existing methods in both objective and subjective evaluation indexes. The proposed Retinex-Net algorithm provides an effective scheme to solve the image quality problem in open-pit mine.

In order to identify extractable uranium ore and enhance resource utilization efficiency,utilizing X-ray transmission technology in conjunction with the semi-supervised learning algorithm - ITSVM,to achieve intelligent uranium ore sorting. At the same time,in order to further optimize the performance of the model,the light and dark correction method is introduced to solve the problem of image noise. This method maps each pixel in the noisy image through normalization processing, so as to improve the image quality. Through the improved straight concave detection and cutting algorithm and slicing method, the difficult problem of multi-objective classification task of support vector machine is overcome. The algorithm detects the position and distance of pixels relative to the straight line,uses constraints to judge the concave point,and obtains the corresponding cutting line by using the minimum distance cutting method. Then the multi-target detection problem is transformed into several independent single-target detection problems by slicing method. By synthesizing these two optimization methods,the ITSVM uranium ore sorting model is finally established. The model was trained and tested by 2 000 uranium ore images collected by Xray projection technology,and the results were compared with SVM and TSVM models. The test results show that the accuracy of the model in detecting uranium ore is improved by 2. 9 percentage points after light and dark correction;The ITSVM model has the function of multi-target detection by using improved straight concave detection and cutting algorithm and slicing method, and the accuracy of the model for multi-target uranium mine image detection reaches 95. 7%. On the test set,the accuracy of ITSVM model to detect uranium ore reaches 97. 3%. Compared with SVM and TSVM,ITSVM has greater advantages in the accuracy of uranium ore detection and continuous optimization model. The experimental results verify the feasibility of ITSMV model in the field of uranium ore sorting.

In view of the difficulty of dust control caused by the diffuse diffusion of dust carried by the compressed air flow in the driving face of rock roadway,a comprehensive dust control scheme of "wind control-purification" was put forward, and an efficient dust removal system for the driving face of rock roadway was constructed,which consisted of a wet cyclone dust collector,an easy-to-assemble and disassemble dust control device and a portable negative pressure air duct. The influence of different installation schemes of the dust removal system on the dust removal effect was compared and analyzed. Considering the dust removal effect and labor intensity,the best installation scheme of wet cyclone dust collector and the best installation position of negative pressure air duct and dust control device are determined. The field application in the driving face of rock roadway in a mine auxiliary transportation roadway shows that when the negative pressure air duct is installed at the opposite side of the ventilation ram,the dust suction port is 3 m away from the roadway head-on,and the dust control device is 5 m behind the air pressure port of the ventilation ram,the high-concentration dust in the head-on is controlled near the head-on under the combined action of the air pressure of the ventilation duct,the air control of the dust control device and the dust extraction of the dust collector,and continuously moves to the dust suction port of the negative pressure duct,and is finally sucked into the dust collector for purification. The dust removal efficiency of total dust and respirable dust in front of the dust collector is above 95. 9% and 94. 9% respectively,and the dust removal efficiency of total dust and respirable dust in the back of the dust collector is above 96. 5% and 95. 4% respectively,which significantly improved the visibility of the roadway and effectively solved the dust control problem caused by ventilation in rock roadway driving face.

Mine operating environment is complicated,all kinds of geological disasters and water disasters are easy to affect underground safety production,so it is necessary to plan the escape path of personnel in advance when disasters occur. In order to obtain the shortest escape route of mine,a path planning method with improved grey Wolf optimization algorithm is proposed. Aiming at the shortcomings of Grey Wolf Optimization (GWO),which is precocious convergence and easy to fall into local extreme values,an improved Grey Wolf Optimization (LT-GWO) algorithm based on the combination of Logistic mapping and Tent mapping is proposed to improve its global search capability. According to the actual working environment of mine,the improved algorithm is applied to underground escape path planning,and the effective path planning results are obtained by setting reasonable path constraints and limiting conditions. The results show that the proposed algorithm is significantly better than the existing algorithms on average path length,standard deviation of path length,average number of iterations and average search time,and has good robustness. The proposed algorithm has a certain reference value for the research of path planning under mine disaster and other emergency scenarios.

To implement the ideological concept of steppe up conservation of the Yangtze River and stop its over development, and realize the green and sustainable development of the Yangtze River Economic Belt,based on the relevant data of 11 provinces and cities in the Yangtze River Economic Belt from 2001 to 2019,a mineral resources-regional economy-ecological environment evaluation system was established. By setting different priorities of the three subsystems,the entropy weight method and the coupling coordination degree model are used to quantitatively analyze the coupling and coordinated development level of the mineral resources-regional economy-ecological environment system under different priorities and select the optimal development mode. The results show that:the coupling and coordinated development of the three systems in the Yangtze River Economic Belt are remarkable,which generally arise from the mild maladjustment interval to the intermediate coordination interval, and the coupling coordination degree value is upstream < midstream < downstream. In terms of provinces,the degree of coupling coordination from low to high is Yunnan,Jiangxi,Guizhou,Anhui,Hunan,Shanghai,Chongqing,Jiangsu,Sichuan,Zhejiang, and Hubei. Except for Hubei,Zhejiang and Sichuan,which are located in the good coordination range,the other eight provinces and cities are located in the intermediate coordination range. Simultaneously,economic priority is only suitable for short-term development,and environmental priority is more suitable for long-term development. Therefore,in order to promote the coordinated and sustainable development of the Yangtze River Economic Belt,the development strategy focusing on environmental protection should be adhered to as a whole,and differentiated measures should be further taken for different provinces and cities.

The mining industry is an important part of the economic sources of resource-based city,and the development and restoration of mines is a key issue for the ecological security of resource-based city. This article is based on the perspective of mining and restoration of mines. It aims to identify the key areas of Jianping County′s mining ecological restoration through the construction of the ecological network. Using habitat quality model and ecosystem service value evaluation to identify ecological sources. The resistance surface is constructed and corrected by comprehensively considering the four aspects factors of natural factors,interference factors,the three controlled lines and mining risks. Ecological corridors were extracted using the minimum cumulative resistance model (MCR). Combined with the mine type,mining method and other factors within the ecological corridor and its buffer range,delineate the mining risk zonings,and clarify the priority of mine mining and restoration. The results showed that:① There were 28 ecological sources in the study area,with a total area of 1 139. 53 km2,and 1 006 km of ecological corridors were extracted. ② The low,medium and high risk areas of mining include production mines and closed mines respectively with an area of 17. 92、10. 62、25. 77 km2 and 22. 5、14. 10、21. 93 km2. ③ According to the degree of influence of the spatial distribution of mines on the ecological network,the mining priority of production mines and the restoration priority of closed mines are divided. Among them,priority mining area,restricted mining areas,the mining area is prohibited include production mine areas of 17. 93,11. 80,and 23. 63 km2,respectively. The very important restoration area,the im-portant restoration area,and general restoration area include closed mine areas of 19. 79 km2,16. 55 km2,and 22. 48 km2,respectively. Based on the above results,relevant regulation strategies and suggestions are put forward for three stages of mining.

The pore structure of reclaimed soil in the bauxite deposit of Guangxi plays a crucial role in soil reclamation quality,but its microstructure characteristics remain unclear. This study aimed to investigate the pore structure features of locally reclaimed soil by examining two reclamation modes:grassland reclamation (RG) and bare land reclamation (RW). X-ray CT scanning technology was employed to scan undisturbed 40 cm soil columns. The ImageJ software and its plugins,in conjunction with the Avizo2020 rendering function,were utilized to obtain parameters that characterize the two-dimensional distribution and three-dimensional characteristics of soil pores. This allowed for the three-dimensional reconstruction,visualization and analysis of soil pore structure. The results indicated a decrease in the quantity of two-dimensional small and medium pores in the soils of the RG treatment model compared to the RW treatment model,while there was a notable increase in the number of large pores in comparison to the RW treatment model. In the 0~20 cm soil layer,the pore surface density of the RG treatment was about 30% lower than that of the RW treatment. In the 20~40 cm soil layer,the pore surface density and pore complexity of the RG treatment surpassed those of the RW treatment. The three-dimensional total pore number was significantly reduced in the RG treatment mode compared to the RW treatment mode. The porosity of the RG treatment (3. 046%) was higher than that of the RW treatment (2. 900%),indicating that the RW treatment resulted in more pores,but not larger ones. The connectivity of the RG treatment (0. 399) exceeded that of the RW treatment (0. 273). However,the tortuosity and specific surface area (1. 329,4. 026 mm-1) were lower in the RG treatment compared to the RW treatment (1. 342,4. 334 mm-1 ). In terms of three-dimensional structure,both treatments had a two-year reclamation time,resulting in a point-like distribution of pore structure and displaying an inclined layered structure. However,compared to the RW treatment,the pores in the RG treatment were mainly distributed in macropores,with clearly visible elongated pores. This suggests that the RG-treated soil is progressing toward a more stable structure. Hence,within the soil reclamation process in Guangxi′s open-pit bauxite mining area,the grassland reclamation model proves more effective in enhancing soil structure and optimizing water and fertilizer transport channels compared to bare land reclamation,ultimately resulting in improved soil quality.

In order to realize the remediation and treatment of composite heavy metal pollution of copper ore dressing and smelting slag,this study focuses on a typical copper smelting slag site in Sichuan,China. Sulfate-reducing bacteria (SRB) were employed as the bioremediation agent to investigate their growth characteristics,the variation of heavy metal ions in solution and the remediation effects. The results demonstrate that SRB can proliferate rapidly during the remediation process,making them suitable for the treatment of composite heavy metal pollution. Due to the significant activity differences among heavy metals such as iron,zinc,copper and lead,their stabilization effects also vary considerably. Within 30 days,the optimal inoculation rates for the four heavy metals of Cu、Pb、Zn、Fe were 5%,10%,15%,and 15%,respectively,with the bioavailability reduction rates of 72. 36%,98. 37%,43. 01% and 79. 31%. As the stabilization period increased,the concentration of heavy metal ions in the solution initially increased and then decreased,but this did not affect the remediation effect. Therefore,SRB can simultaneously remediate multiple heavy metals,effectively addressing the composite heavy metal pollution of iron,zinc,copper,and lead in the typical copper smelting slag in Sichuan.

In order to solve the problem that the cementitious materials are easy to expand when exposed to water and affect the strength in the in-situ repair process of solid waste landfill leakage. KH560 with amphoteric groups was added to sodium polyacrylate and electrolytic manganese slag by two-step aqueous solution polymerization method to prepare electrolytic manganese slag-based composite cementitious materials. The compressive impermeability and corrosion resistance of the consolidated body were analyzed by water seepage test and corrosion test,the molecular structure of the consolidated body was characterized by infrared spectroscopy (FTIR),and the surface morphology and element content changes of the consolidated body were analyzed by SEM-EDS,and the mechanical enhancement mechanism and anti-seepage mechanism of KH560 on the electrolytic manganese slag cementitious material were revealed. The results show that:① the compressive resistance,impermeability and corrosion resistance of the composite cementitious material can be significantly improved by adding KH560 in an appropriate amount 3%,and the unconfined compressive strength of the consolidated body is 2. 25 times that of the consolidated body without KH560,and the permeability coefficient is 61. 3% lower than that of the consolidated body without KH560,and the corrosion resistance coefficient is 0. 85. ② The siloxy group Si—OCH3 in the molecular structure of KH560 underwent a hydrolytic condensation reaction with the free water in the electrolytic manganese slag to form a Si—O—Si connection structure,which reduced the water gap channel,made the surface of the consolidated body smooth,and significantly improved the impermeability effect and corrosion resistance.

In order to study the effect of fine iron tailing powder content on pore structure and mechanical properties of high-strength concrete materials,the micro-pore structure,porosity and mechanical properties of samples with 0%,5%,10%, 15%,20%,25% and 30% fine iron tailing powder content were measured by nuclear magnetic resonance detection device and electro-hydraulic servo press. The effect of fine iron tailing on the porosity,tensile strength and compressive strength of the specimen was analyzed. The results show that:① The T2 spectrum curves of high-strength concrete specimens with fine iron tailing powder all show a three-peak shape. With the increase of fine iron tailing powder content,the porosity of specimens decreases from 2. 81% at 0% to 2. 10% at 30%. The porosity of specimens decreases continuously,and the decline of porosity in the early stage is more significant. ② The internal pore structure of the specimen is dominated by the proportion of micropores and medium pores. With the increase of fine iron tailing powder,the proportion of micropores increases,while the proportion of medium pores,large pores and cracks decreases. The addition of fine iron tailing powder can optimize the internal structure of the concrete. ③ When the iron tailing powder content is 20%,the compressive strength and tensile strength of the specimen are improved,but excessive incorporation will reduce the mechanical properties of the specimen.

The phosphogypsum road base material designed by traditional mineral mixture is difficult to meet the demand of large-scale consumption of phosphogypsum. In order to realize the large-scale utilization of phosphogypsum in road base material, the mix ratio design of high-volume phosphogypsum road base material was explored with aggregate substitution method to determine the propriate graded gravel ratio (mass ratio of 5~10 mm and 10~25 mm fraction of 39∶61). As a substitute for the phosphogypsum-based cementitious material system,the aggregate with different dosages were employed to reach the optimum water content and maximum dry density by compaction. The performance test was carried out with the designed mix ratio to screen the propriate ratio as P85S60. For P85S60,the 28 d compressive strength reached 5. 39 MPa,but the volume change rate was low,and the volume growth became stable after 7 days with the ultimate volume change rate as about 0. 5%,which was conducive to the application of on-site road construction. The fluorine and phosphorus content in the leaching of all ratios meets the first-level limit of Integrated Wastewater Discharge Standard (GB 8978—1996),and the pH of the leaching solution would not increase additional adverse effects compared with conventional cement stabilized crushed stone materials. According to results from XRD and SEM,it can be found that ettringite and hydrated calcium silicate produced by the hydration of the cementitious material wrapped around the unreacted dihydrate gypsum. In addition,needle-shaped ettringite and hydrated calcium silicate fill tiny pores,making the overall structure dense to form big strength and volume stability.