Recently，the exploration of cobalt resources in the Jingchong-Beishan area，the east of Changsha-Pingjiang fault zone，northeastern Hunan Province，has made great advances.Some Co （-polymetallic） vein deposits including the medium-size Jingchong Cu-Co polymetallic deposit and Hengdong Co-Cu deposit，and Dayan Au-Co occurrence were discovered in this region.Based on the detailed field observation，this study identified the ore stages，and concluded the metallogenic characteristics of Changsha-Pingjiang cobalt ore belt as well as the ore-forming factors.The combined microscopic observation and in-situ analytical methods revealed that the metal Co was mainly incorporated in fine-grained pyrite and arsenopyrite as stoichiometric substitution，with subordinate occurrence as independent mineral cobaltite.The complicated texture and chemical compositions of Co-beating pyrite and arsenopyrite indicated that pyrite associated with arsenopyrite has the higher Co concentration （up to 13.48%），greater than that in arsenopyrite-exclusive assemblages.Therefore，the mineral assemblage of fine-grained pyrite and arsenopyrite can be used as the mineral fingerprint to trace the high-grade Co ores during the prospecting exploration.Subsequently，the preliminary mineral processing technology was proposed.
Research progress on the biomineralization technologies of sulfate-reducing bacteria （SRB） and iron-oxidizing bacteria （IOB） for removing arsenic from acid mine drainage （AMD） is reviewed. Although there are numerous studies on the removal of arsenic from AMD using SRB，there remain several challenges in the implementation of this remediation technique on a large scale. These challenges include the choosing of carbon sources，the low-level resistance of SRB to arsenic and the high requirement for reactors. Removing arsenic from AMD using IOB is still at the stage of laboratory research given that the stability of different minerals formed during the biomineralization is not very clear. However，this remediation technique has advantages in accelerating the oxidation of As（Ⅲ），the high-level resistance of IOB to arsenic and the low cost for reactors，which has a promising prospect.
Antimony-bearing gold ore is a common refractory gold ore.Gold is often wrapped in antimonite and other sulfide ores，due to the presence of antimony，the extraction rate of gold is often low when leaching by the traditional cyanide method.Removal of antimony minerals through pretreatment method is of great importance to enhance the leaching efficiency of gold.This paper introduces the recent development on the pretreatment methods，such as flotation，roasting，acid or alkaline leaching，biological leaching and pressure leaching.The advantages and disadvantages of different processes were compared and the status quo of industrialization of each process was analyzed.Based on the research results， it is believed that the research of antimony-bearing gold mines should be developed in a more environmentally friendly， more efficient， and safer direction.Therefore，hydrometallurgy has become the focus of research.The application of new process methods and the development of new agents can not only ensure high efficiency and safety，but also ensure environmental protection and economy.
The Bannian gold deposit is located in the southern part of the Laizishan orefield in the north of the Nanpanjiang-Youjiang metallogenic belt，and the gold deposit is controlled by the SN direction Laizishan anticline and the NE，NW fault in the mining area.According to the geological survey and geochemical analysis，the slip structure between the thick carbonate and thin clastic rocks is developed，the lower carbonate deformation is weak，and the upper clastic rocks are crushed and deformed strongly，forming an uncoordinated secondary folding faults are conducive to fluid migration and migration.Alteration and mineralization in the detachment structure zone and the fault are obvious.The detachment structure zone is the main channel of ore-forming fluid migration and the location of gold orebodies.The structural alteration bodies（SBT） formed by the metamorphic fluids in the Luolou Formation，Manchu/Wujiaping Formation，or reef limestone，Xinyuan Formation/Anshun Formation，are the main alterations in the area.Gold mineralization is the main target layer for prospecting in the area.Through comprehensive analysis，we conclude that the intersection of deep F1，F2 faults in Dagou-Ceyang area and the superposition of deep F6 faults and anticlines in Banna-Fengbao area are the best ore prospecting sites.The coupling part of the secondary anticline and F22 faults in the north west wing of the Laizishan anticline in Beiyinpo-Shibanjing area has certain prospecting potential.
Erdaogou gold deposit is a magmatic-hydrothermal deposit hosted in continental volcanic rocks in Liaoning Province，its orebodies are strictly controlled by structures.Predecessors have done a lot of research on the genesis of Erdaogou gold deposit in Liaoning，and carried out a lot of exploration and prospecting work in the mining area， and found some new veins， but the deep prospecting prediction of some mined veins are relatively weak.After years of mining and production， the mine urgently needs to increase resource reserves to maintain development. At present， the control length of No.1 and No.3 veins are about 680 m， while the control length of No. 5-1 vein on the west has reached 1 600 m，and the deep part of No.1 and No.3 veins may still have a certain scale extension.At present，except for the deep prospecting prediction by using the thermoelectricity of pyrite at the middle section of the 250 m to -215 m depth of the No.3 vein， the systematic research on the No.1 and No.3 veins have not been carried out.In order to predict the extension，metallogenic environment and mineralization of No.1 and No.3 veins，this paper systematically studied the thermoelectric characteristics of pyrite，ore-forming temperature，veins denudation rate，XNP mean and the occurrence rate of different elevations of P-type pyrite of the samples at the 450 m to -305 m depth.The results show that the ore-forming temperatures of No.1 and No.3 veins are 130~280 ℃，which belong to medium-low temperature hydrothermal deposits.The average denudation rates of No.1 vein is 45.89%，the contour of denudation rate becomes a low value area to the deep and is not closed，the thermoelectric conductive types is mainly P type， P-N type and mean value of XNP at the -305 m depth is 83.33（upper part of vein），the occurrence rate of P-type pyrite at the middle section of -215 m increases. The average denudation rates of No.3 vein is 50%.The contour of denudation rate becomes a high value area and is not completely closed，the thermoelectric conductive types is mainly P-N type and N-P type，mean value of XNP at the -305 m depth is -8（middle part of vein），the occurrence rate of P-type pyrite in the middle section of -215 m decreases，which show the middle section of -305 m is the middle and upper part of No.1 vein and the lower part of No.3 vein.The deep part of No.1 vein extends greatly，while the No.3 vein still extends partly to the depth.The metallogenic environment of No.1 vein is gradually stable and greatly mine-ralized at the -215 m depth，but the metallogenic environment of No.3 vein changes from turbulent to stable and mineralization is better at the -260 m depth.
During the 1990s，with the deepening of research and exploration of carlin-type gold deposit in China on the basis of the connotation of carlin-type gold deposit，some gold deposits were discovered and redefined as carlin-like gold deposits.This is a class of gold deposits that show similar geological characteristics to the carlin-type gold deposit，but their geochemical characteristics are obviously different.The Zhaishang gold deposit located in the western part of the Li-Min metallogenic belt within the western Qinling Mountains is a very important carlin-like disseminated gold deposit.Since it was discovered through geochemical anomaly information and civil mining information in 2 000，many workers have carried out geological，geochemical，geophysical，remote sensing，engineering and other aspects of exploration，as well as researches on mineral composition，texture and structure of rock，orebody distribution，fluid source and ore-forming conditions，showing the superior metallogenic geological conditions and great prospecting potential of the deposit.Based on a large number of field work data and analysis of ore-forming characteristics in the mining area，we mainly studied the No.31 vein and the Zhamashu ore section in the South ore belt，taking the measurement and analysis of structural traces of different scales as the basis.On the basis of the analysis of the ore control law of the structure，the “three in one” ore-forming model of ore-forming geological body，ore-forming structure，ore-forming structural plane and ore-forming characteristics was summarized to guide the prospecting systemati-cally.The results of field observation and statistical analysis on the structural fissures of the Zhaishang gold deposit show that the most developed joints are in the NW-SE direction of 106°~137°，and the joints in the NE-SW direction of 196°~229° come second.It is indicated that the SN-trending compressive stress in Indosinian period，which is an important structural period of the gold deposit，formed most of the joint fractures of the deposit.And the deposit is mainly formed in Indosinian and Yanshanian tectonic movements，the orebody is controlled by folds，faults and strata.In Yanshanian period the deposit was mainly controlled by NE-trending positive torsional stress，which led to the successive activity of NW-trending structure formed in the Indosinian period，the emplacement of magmatic hydrothermal fluid along fractures，the mixing of atmospheric precipitation，and the superimposition of mineralization on the early orebodies.
The Qiujidonggou gold deposit in Dulan County is located in the middle of the east Kunlun metallogenic province，so it is necessary to carry out research on the reverse side of mineral exploration.The area has developed structures，frequent research activities，and a good metallogenic geological background.There are famous Wulonggou gold deposit and Tanjianshan gold deposit around the mine.Due to the good metallogenic background in this area，the area has attracted the attention of scholars at home and abroad.Most of the previous studies have focused on the geological characteristics of the deposits and the metallogenic age，and there are few studies on regional mineral exploration，which has led to no breakthrough in regional prospecting. Because the mining area is large and the coverage is serious，general physical and chemical exploration methods are difficult to meet the exploration needs，which limits the prospecting and mining work of the mine.In order to reveal the metallogenic characteristics of the ore bodies in the study area and the prospecting direction，this paper explores the 1∶25 000 water system sediments in the Qiujidonggou gold deposit，to explore the mineralization characteristics and delineation of the deposit mine target area.Through research，it is found that the four elements Ag，Pb，As and Sb are highly correlated with metallogenic elements and can be used as indicator elements for metallogenic.Using the method of contrast anomaly delineation，four comprehensive anomalies were delineated in the study area.One type I anomaly is the AS-4 comprehensive anomaly and the second type anomaly is the AS-1 and AS-3 anomalies，third type anomaly is the AS-2 anomalies.This will provide a theoretical basis for the theoretical research and prospecting direction of regional prospecting.
For the ore-forming process of hydrothermal deposits，the seepage of fluids in the rock matrix and fissures （faults） produces material and energy transmission，and forms orebodies at specific locations with changes in temperature and pressure.Because the width of the fault is much smaller than the dimension of its extension direction，it causes problems such as difficulty in modeling numerical models and low calculation efficiency.According to the geometric characteristics of the fault，it can be generalized into a space surface to reduce the difficulty of modeling.The generalized fault uses the cubic law in rock mass fracture seepage theory to calculate the fault seepage problem.The seepage of hydrothermal fluid is not limited to faults，but also occurs in bedrock，and this process is calculated using Darcy’s law. The fracture flow in the fault and the Darcy flow in the bedrock interact with each other.In order to ensure the continuity of the pressure，velocity，mass，and energy of the seepage field in the numerical model calculation domain，the flow-heat coupling calculation is required.The purpose of this study is to verify the feasibility and rationality of the generalization method of the fault space surface，and to solve the problem of flow-heat coupling between the fissure flow in the fault and the Darcy flow in the bedrock.The viscosity of fluid has the property of changing with temperature.This article will discuss whether the change of viscosity has an effect on the calculation result of the numerical model initially.Based on the theoretical formula of cubic law，the formula is derived according to the characteristics of small fault thickness，and the flow-heat coupling control equation of fracture flow and Darcy flow is obtained. In order to verify the rationality of the control equations，numerical model experiments are used for verification and analysis.After analysis，it is considered that the method of calculating the seepage of the fault using cubic law is feasible when the internal structure of the fault is not taken into consideration，which can reduce the difficulty of modeling the numerical model.Because the fault uses a spatial surface，the reduction of the dimension compared to the overall model also brings increased computing efficiency. After analyzing the results of the numerical experiments，it is considered that the coupling control equation is reasonable and effective for the calculation of the flow-heat coupling between the bedrock and the fault，which is in accordance with the laws of seepage and heat conduction.Based on the original experimental numerical model，a model in which the viscosity coefficient of the fluid does not change with temperature is established，and the change curves of mass and heat conduction flux are compared.It is found whether the change of the fluid viscosity is considered to have a significant effect on the calculation result of the numerical model.
Mineral resources are the foundation of social development.Projects such as efficient and safe tunneling and opening roadways are one of the main tasks of underground mines.Due to the differences in the geological conditions of the underground rock layers and the non-selective engineering environment，the roadway support in the soft broken section of the fault has an important impact on the construction and operation safety of the mine roadway.Taking the tunnel development project of the soft-segmented section of F4 fault in Tiaoshuihe Phosphate Mine as an object，we studies how to improve the engineering stability of the roadway by reasonable support design under the influence of F4 fault，the roof structure is poor，and the floor and surrounding rock are relatively soft.Finite difference software FLAC3D was used to construct a three-dimensional numerical simulation model of the mine roadway.A Mohr-Coulomb model was used in this study.The model size is 40 m × 40 m × 40 m，the fault thickness is 8 m，the inclination angle is 75°，and the burial depth is 250 m.The side and bottom of the model are fixed boundaries，and the upper surface is not constrained.The side pressure coefficient is λ=1.2 with reference to Yichang area.The optimization of the support parameters involves three factors：The length of the anchor rod，the thickness of the shotcrete and the thickness of the masonry.Based on the investigation of its engineering geological conditions，an orthogonal experiment scheme of 3 factors （including 1 factor of 4 levels and 2 factors of 2 levels） of support parameters was designed.Based on the analysis of the support effect and deformation law of different parameter combinations，the length of the anchor rod，the thickness of the shotcrete and the thickness of the masonry were reasonably selected under the economic conditions，which provides theoretical basis for the final support mode and parameter optimization.The supporting method and parameters of the roadway were determined by range analysis.The research results show that：（1）The orthogonal experiment design can effectively reduce the number of experiments and improve the calculation effect.The analysis of variance of the calculation results identified the influencing factors of different results.The main factors affecting the displacement of the top and bottom plates，vertical stress，and sideways displacement of the roadway are the length of the anchor rod，the thickness of the concrete，and the thickness of the masonry.Reasonably selecting the size of support parameters is conducive to improving the effect of support.（2）Taking the displacement and stress of the roadway in the soft fault section as the research object，the optimal supporting scheme is determined as bolt length of 2.8 m，shotcrete thickness of 100 mm and arch thickness of 250 mm.The numerical simulation further verifies that the supporting effect under this parameter is conducive to improving the engineering stability of the soft fault section.（3）This study provides technical reference for the excavation and support of roadway of phosphorite and metal deposits with similar geological conditions，and has good demonstration and guidance significance.
At present，many researches have been carried out on the static and scientific characteristics of hard rock in deep underground and the dynamic response of intact rock under dynamic impact load.However，the damage and fracture mechanism of the fracture free zone in sandstone under the action of blasting stress wave has not been thoroughly studied.In order to solve the problem of difficult coring of the original rock in the deep part of the coal mine，this paper conducts six cyclic threshold tests on the similar material of sandstone，namely cement mortar，and sets the upper limit of cyclic stress as 20%，40%，60% and 80% of the static strength.One dimensional dynamic impact compression tests were carried out with the impact pressure of 0.4，0.5 and 0.6 MPa respectively.Finally，the relationship of stress，strain and strain rate under dynamic conditions was obtained.Based on the analysis of the dynamic and static strength changes of similar sandstone blocks before and after damage， the dynamic strength is lower than the static strength at the same damage degree.The strain rate does not affect the shape of the curve，but the rise of the cycle threshold causes the peak point of the curve to move to the lower right corner.The relative value of the stress sensitive factor decreased at a different rate before the cycle threshold of 60% and after the cycle threshold of 60%.The test results show that the strength decrease caused by damage under dynamic conditions to be higher than static conditions，which is because of cyclic loading and unloading causes the internal elasticity of the test block to decrease and the shape to increase.After the cycle threshold reaches 60%，the dynamic impact damage reaches the threshold value，which is consistent with the static analysis results.Both peak stress and peak strain have strain rate effect，but the coupling effect of impact load is more significant at low strain rate，and it will no longer work beyond the breaking strain rate.
In subways，tunnels and other projects，the loading rate effect produced by short-time，high-strength excavation is one of the main factors of engineering disasters. With the widening of demand and the deepening of research，it is of great significance for the safety protection and stability evaluation of rock engineering to carry out studies on the mechanical effects of loading rate and the influence of crack dip angle related to time factors. In order to investigate the fracture law of fractured rock-like materials combined with loading rate and fracture dip angle，RMT-150B rock mechanics testing machine was used to perform static to quasi-static 4-level loading rate uniaxial compression of rock-like materials with 0.1 mm prefabricated cracks.Based on acoustic emission testing technology，the initiation strength law of rock-like materials with preset cracks and the dynamic frequency domain change characteristics of rock mass fractures under the combined action of loading rate and crack dip angle was analyzed. The main research results show that：Under the same loading rate，prefabricated cracks with different dip angles have different degrees of damage to the compressive strength of rock-like specimens，and the peak strength shows a trend of decreasing first and then increasing with the increase of the prefabricated crack dip angle，and the minimum angle is 45°. When the fracture inclination angle is the same，the peak strength of the fracture body increases with the increase of the loading rate. There is a critical loading rate in the quasi-static loading range，so that the loading rate strengthening effect is no longer significant，that is，the growth of the fissure body basically stagnate after reaching a certain value.This critical loading rate is around 2.0×10-4 s-1.Acoustic emission activity begins to be apparently active after the end of the micro-crack closure phase in the specimen.A large number of micro-cracks initiate and penetrate each other to form macro-cracks.The AE energy rate is most active around the peak.Under the same loading rate，the cracking stress level of the fracture body increases with the increase of the inclination angle.When the crack inclination angle is the same，the cracking stress level of the fracture body increases with the increase of the loading rate.Under the condition of static loading，the cracking stress level of the fracture body with an inclination angle of 0° is roughly between 60 and 70 percent，that is，about two-thirds of the peak stress.With the increase of the inclination angle，the cracking stress level is also increase，the cracking stress level of the fractured body with a tilt angle of 90° under quasi-static loading conditions has exceeded 90%，and the cracking stress levels of the complete specimens within the static-quasi-static loading range have all exceeded 90%.
The deep mining has become an inevitable trend of the world’s metal deposit mining with the depletion of shallow metal mineral resources.The surrounding rocks in deep stopes and roadways are often in a complex stress environment of “three highs and one disturbance”.The surrounding rocks in deep roadways often suffer from collapsed，rock bursts and other damages，which causing ore loss and depletion，equipment damage and casualties，and seriously hindering the production of mines.The Sanshandao gold deposit is the earliest discovered large-scale gold deposit of altered rock in the broken zone.The structure faulted is the mainly faulted in the area.The Xinli fault zone located in the northeast of the Sanshandao-Cangshang fault zone is an ore-controlling faulted structure in the mining area.The rock mass in the fault zone is subject to strong weathering and tectonic movement.The cracks are very developed and the surrounding rock strength is low.The roof collapse often occured during tunneling.Therefore，it is necessary to take timely and effective support measures for deep high-stress fractured surrounding rocks.In this paper，the deep roadway of Sanshandao gold mine is used as the engineering background.Through field engineering geological surver，and the discontinuity information of surrounding rock at -1 005 m level in Sanshandao gold mine was obtained.The surrounding rock is mainly distributed with three sets of joints，and one set is nearly parallel to the axial direction of the roadway and the inclination angle is about 90°.The laboratory studies were carried out.Rock mass classfication were estimated，accordingly.Q=1.5，RMR=40.25，GSI=35.The quality of the rock mass is poor.Roclab software was used to estimate the mechanical parameters of the rock mass，and the compressive strength and tensile strength of the rock mass are 3.477 MPa and 0.003 MPa，respectively.The rock mass strength is low.Based on the support charts with RMR and Q，the shotcrete + anchor + reinforcement mesh + double bars support method was adopted in the study area.The RS2 and Unwedge software were used to analyze the change characteristics of surrounding rock plastic zone，displacement and potential wedge safety factor before and after roadway support.The results show that after the roadway is supported，the vertical displacement of the roadway roof is reduced from 2.2 cm to 0.76 cm.The plastic zone of the roadway roof is reduced from 4.481 m to 1.634 m，the leftwall plastic zone is reduced from 1.760 m to 0.859 m，and the rightwall plastic zone is reduced from 1.830 m to 0.860 m，the safety factor of the potential wedge of the roadway roof increased from 1.5 to 22.7.The plastic zone and displacement of the surrounding rock are significantly reduced，and the potential wedge safety factor is significantly increased.The proposed support scheme can ensure the stability of the roadway.Therefore，the comprehensive research method of combining the empirical method and numerical simulation can accurately to analyze the stability of the roadway and determine a more reliable support scheme.It provides a reliable guarantee for the mine safety production.
In the process of mining，the mining technology mainly based on the open field method will leave a large number of goaves after mining，which has great safety risks.Therefore，the prediction of the stability of the goaf is particularly important.In recent years，with the advent of the era of big data，machine learning and deep learning technology has been introduced into the mining industry.More and more scholars begin to use the prediction method of machine learning to study the stability of goaf.It is found that every single machine term model has its scope of use and scene，when facing a new goaf problem，we can not immediately give the most effective model to adapt to it.At this time，the stacking method derived from integrated learning is born.This article is mainly divided into three parts.The first part mainly introduces the Stacking method，explains the main steps of the method and the choice of the learner.Stacking is generally a two-layer structure.The first layer is composed of various elementary learners.Input the original data set to train them.The second layer uses the output of these primary learners as a new data set and new features into the secondary learner （meta-learner） for training，to complete the stack fusion of the model.The Stacking model requires that the correlation between the primary learners should be as small as possible，and the performance difference between the primary learners should not be too large.The second-level learner should choose a simpler learner.The second part is the construction of Stacking model.This paper selected eleven factors affecting the stability of mined-out area，they are the rock mass structure （X1），geological structure（X2），groundwater （X3），goaf engineering layout （X4），mining perturbation（X5），adjacent cavity （X6），the volume of the goaf （X7），the exposed area of goaf roof （X8），buried depth （X9），goaf span mined-out area ratio （X10），rock compressive strength（X11）.By using the eleven dimensional data and the classification of goaf stability as training data，we put them into the stacking model with random frost，AdaBoost，extratrees and lightgbm as primary learners and logistic regression as secondary learners for training.Another part of the training data was used as test data to compare the performance of stacking model and single machine learning model.The experimental results show that the F1 and AUC of stacking model are 0.967 and 0.97 respectively.Far higher than all other single machine learning models.The stacking model is better than other single machine learning models and show stronger generalization ability.Therefore，as the third part，it is concluded that the stacking model can predict the stability of goaf better than the single machine learning model.
In the primary stage of mining area development，economic growth should be realized by relying on resource endowment of mining area.The high consumption of resources and energy and the high input of production factors give rise to the huge cost of environmental damage in the mining area，the pollution problems are evolving from simple one-way to complex ones.The system of compensation for ecological and environ-mental damages is conducive to solving the law enforcement dilemma of “corporate pollutes， residents victims， government pays”，and helping China’s ecological and environmental protection to the depth of development.However，ecological safety evaluation can provide a basis for the diagnosis of ecological environment quality and compensation for damages in mining areas，and they are also an important part of high-quality development of mining area economy.Aiming at the low accuracy of themining ecological security evaluation，the index system for mine ecological security evaluation was designed，including mining environment quality，pollutant discharge or emission，ecological protection，carrying capacity and the coordination of ecological system.Furthermore，20 secondary indexes were set，such as vegetation coverage rate，pollution source diffusion rate，land reclamation rate and so on.The quasi-optimal classification hyper-plane was constructed based on selected kernel function to combine Wavelet Theory with Support Vector Machines，and an integer hybrid model was established.The evaluation model was applied to the ‘G’ rare earth mining area，and the results show that there are 10 samples with grade Ⅰ risk level，that is，their environment are poor，and there are 8 samples with grade Ⅱ risk level，that is，the environment is poorer.Compared with results by GIS identifying，the error rate of the model is 5%，which has better warning accuracy.Further，compared with BP neural network，ARIMA and other methods commonly used at present，the proposed model has well-forecasting performance，can represent the nonlinear time series well.So，it has a good application prospect in the field of nonlinear time series.
Mine safety is the foundation and premise of the sustainable development of mining industry.To do well in mine safety work is very important to ensure the development of regional economy and the safety of citizens’ personal and property.With the increase of mining scale and mining depth of mineral resources，the situation of mine safety production is becoming more and more complex，and various kinds of safety accidents happen frequently，which brings inestimable consequences to the country and the people.Therefore，in order to evaluate the situation of mine safety production accurately，reduce the accidents of mine safety production and ensure the sustainable development of the mine，the evaluation model of mine safety production status （MSPS） based on combination weight and matter element analysis was established.Firstly，according to the influencing factors of mine safety production，an evaluation index system of MSPS was constructed，which takes safety management，safety technology，safety production education and training and safety environment as the standard level，containing 12 evaluation indexes such as safety production management organization and safety management system as the index level.Industry experts scored each evaluation index，and we summarized and normalized the scoring results.Then the matter-element transformation was used to determine the classical domain，nodal domain and the matter-element of evaluated mine matter-element.The correlation degrees between the evaluation indexes and the established safety levels were calculated step by step，and the concept of distance function was introduced into the combination of analytic hierarchy process and entropy weight method for weighting to accurately determine the combination weight of mine safety production evaluation index.Finally，the grade of MSPS can be obtained from the comprehensive correlation degree between evaluation indexes and established safety levels.After calculation，the safety grades of five mines under a mining group are respectively grade Ⅱ，grade Ⅲ，grade Ⅱ，grade Ⅰ and grade Ⅱ.The fuzzy comprehensive evaluation method was used to verity the results，and the two evaluation results are consistent.The research results show that the weight of evaluation indexes calculated by combination weighting method are more scientific and reasonable because it can avoid absolute subjectivity and objectivity.In addition，the evaluation model of mine safety production based on the combination weight and matter-element analysis provides an effective technical way for the study of mine safety production，which is helpful for the formulation and completion of the best mine safety production management plan.It is of great guiding significance to improve the safety production guarantee system of mines.
Rockburst is one of the key scientific problems that must be solved in large-scale underground geotechnical engineering and deep mineral resource mining.The safety of personnel and equipment on site was directly threatened by rockburst.Rockburst could be effectively avoided and controlled in time by scientific and accurate rockburst prediction of intensity classification.Through the analysis of six rockburst engineering examples，on the basis of the factors，characteristics and causes of rockburst，a rockburst prediction index system composed of four evaluation indices，i.e.，tunnel-wall surrounding rock’s maximum tangential stress，rock uniaxial compressive strength，rock uniaxial tensile strength，and rock elastic energy index was established.With reference to other rockburst intensity classification schemes，considering the intensity of rockburst occurrence and the main influencing factors，the rockburst intensity was divided into four levels：None rockburst（Ⅰ），slight rockburst（Ⅱ），intermediate rockburst（Ⅲ） and strong rockburst（Ⅳ）.According to the selected rockburst evaluation index and rockburst intensity grade，a literature survey method was used to establish a database containing 301 groups of rockburst engineering examples，which would be used as the sample data for rockburst prediction.In order to accurately and reliably predicted rockburst disasters，machine learning technology was introduced.First，a random forest-based rockburst evaluation index importance analysis model was established，a new index weight calculation method of random forest-analytic hierarchy processs was proposed，and the rockburst prediction model based on the RF-AHP-cloud model was constructed.Then，the firefly algorithm based on good point set variable step strategy was introduced to optimize the penalty parameters and radial basis function parameters of the support vector machine，and the rockburst prediction model based on ⅠGSO-SVM was constructed.Finally，the Dropout method was used to regularize the model，and the improved Adam algorithm was used to update weight，and the rockburst prediction model based on DA-DNN was constructed.The effectiveness and correctness of the three models were validated by the prediction results of 60 groups of rockburst engineering examples.The research results show that：The DA-DNN，ⅠGSO-SVM，and RF-AHP-cloud model have prediction accuracy rates of 98.3%，90.0% and 85.0%.The core of rockburst intensity classification prediction based on cloud model is weight determination，and the RF-AHP weight calculation method proposed in this paper has a good effect.The data-driven ⅠGSO-SVM and DA-DNN models are based on rockburst engineering instance data.Through data mining，the rockburst intensity level can be effectively predicted，and higher prediction accuracy can be achieved by improvement.The theory of DA-DNN model is easy to understand，the coding is relatively simple and it is easy to implement.As various underground geotechnical engineering develops deeper，rockburst disasters occur frequently，the amount of rockburst data is increasing，and the DA-DNN model has a wider application prospect.
Mine fans at high altitude region plays an extremely important role in the mining process of mineral resources.The mine fans provide a guarantee for the safe mining of mineral resources by providing fresh air and eliminating toxic and harmful gases，so they are an important part of safe production.It is of great practical significance to carry out a scientific assessment of the operation status of mine fans to promote the safety management of mine fans. In view of the complexity of the environment in which plateau mines are located，the mine fans evaluation index system was constructed，including one overall objective，four middle factors and sixteen criteria. Due to the uncertainty in the calculation process of the index weights，the weighted interval was calculated using the analytic hierarchy process （IAHP）. In order to obtain the accurate index weights，the 3-element connection number was used to convert the interval weights into accurate weights.Therefore，the uncertainty in the process of obtaining index weights can be effectively resolved，making the index weights more reasonable. In addition，the establishment of five-element identical-discrepancy-contrary evaluation model realizes the purpose of static assessment of the mine fan.The partial connection number theory in the set pair theory is introduced to predict and evaluate the operation state of the mine fan.Thereby realizing the static and dynamic evaluation for fans at high altitude region.The operation status of the mine fans is evaluated from the static and dynamic dimensions，making the evaluation results more practical.Finally，an example of a mine fan in Yunnan Province was introduced to verify the applicability and effectiveness of the method.The evaluation result of the operation state of the mine fans is medium level. In addition，the operation state of the mine fans was analyzed using partial connection number.Therefore，the future development trend of the indicators of mine fans can be predicted.The analysis results show that these indicators，namely environmental humidity，external structure status and personnel’s physical condition，will decline sharply in the future.Therefore，those should be classified as high risk factors，and corresponding management measures and technical measures should be proposed to improve the operation status of the fan.The evaluation results provide an important reference for the safety management of mine fans in the plateau area，and can effectively prevent the accidents caused by the poor operation of mine fans.Therefore，the method proposed can be used to evaluate the status of mine fans in the plateau area，which can not only grasp the current operation status of the fan，but also predict the development trend of the future status of the fan.The targeted suggestions for fault diagnosis，risk management and optimization of mine fans in the plateau area can be put forward.
The pretreatment methods for gold-bearing sulfide ore mainly include roasting，biological oxidation，pressurized oxidation，acid oxidation，alkaline oxidation，etc.The alkaline oxidation process has become a research hotspot in recent years due to its many advantages，such as low requirements for equipment，simple flowsheet，environmentally friendly，low production cost and so on.The authors found that while the sulphide minerals oxidized，gold simultaneously had been dissolved mostly in the process of gold concentrate alkaline oxidation.Through the analysis and research on this phenomenon，the sulfide anions，such as Sx2- and S2O32-，were thought to play a major role for dissolving gold.Therefore，a technical idea of synchronous gold extraction from gold-bearing sulfide ore by self-coordination of gold and sulfur.So，the author has extensively consulted relevant research materials at home and abroad.These studies have focused on oxidation and passivation of sulphide，leaching and passivation of gold，etc.，and the mechanism of gold leaching in alkaline sulfur-containing solutions were presented from different aspects，including thermodynamics analysis，electrochemical dissolution，and leaching kinetics.Research methods involves SEM，XPS，EQCM，XAFS，etc.The main conclusions drawn from these research materials are as follows：Firstly，in alkaline solutions，sulfide is easily oxidized to polysulfide and thiosulfate，which can solubilize gold.But these polysulfide ions are unstable and will eventually be oxidized to stable forms such as sulfate and sulfite in the presence of oxygen.Secondly，both gold and sulphide can be passivated in the alkaline oxidation process.Sulphide can be oxidized generate Fe（OH）3，FeAsO4 and other precipitates，which forms a passivating layer on the surface of sulfide minerals and gold，preventing the further oxidation decomposition of sulphide and the dissolution and leaching of gold.Passivation inhibition can be reduced or eliminated by mechanical stripping or by adding appropriate dispersants.At present，researches on gold-leaching by the alkaline oxidation of gold-bearing sulfide ores are more，and leaching system involves the NaOH-NaClO-NaCl system，NaOH-NaCN system，NaOH-Na2S-S system，NaOH-Sx2– system，copper-ammonium thiosulfate system，alkaline thiourea system，etc.Generally，a better gold leaching rate can be achieved in laboratory，but there are problems for industrial application，for example，dosage of lixiviants is high，gold-leaching ions is unstable，the catalyst is needed and so on.How to effectively reduce the useless consumption of lixiviants is the key to the wide application of alkaline sulfide gold leaching technology.The mechanism on dissolution and passivation of sulfide and gold in alkaline gold-leaching system were systematically summarized and analyzed.On the basis of own research the authors put forward the technical idea of self-coordination simultaneous dissolution of gold and sulfur from sulfide ore.Namely，we can directly leach gold in alkaline leaching gold system by utilizing the sulfur of gold-bearing sulfide ores，which are oxidized to generate polysulfide and thiosulfate having the ability to oxidize and coordinate for the gold.This technical idea likely is an effective way to solve before-mentioned problems for industrial application.Some data indicate that gold was enriched and precipitated out from sulfide minerals during crustal movement，instead of being transported by metamorphic pyrite.It suggests that in certain magmatic hydrothermalism conditions，sulfur and gold of sulfide ore likely had ever formed some gold-sulfur compounds.On the base of geological form causes analysis for the gold-bearing sulfide ore，the author points out that the sulfide ions are likely to be effective lixiviants to replace cyanide for the gold leaching.The author also discusses the key scientific and technological problems that need to be solved in this field，and points out that oxidizing sulfide to convert into polysulfide and thiosulfate and keeping the stability of the gold-sulfur complexes are the most important problems to be solved in this technique.
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