The newly-discovered Qianhongquan gold deposit is located in the southern part of the Beishan orogenic belt，but there is a lack of accurate constraints about its metallogenic epoch.In this work，the altered sericite from the ores of this deposit was dated using 40Ar-39Ar.The 40Ar-39Ar plateau and isochron ages of the altered sericite are （250.4±1.0）Ma and （251.3±1.1）Ma，respectively，indicating the ore-forming age is Early Triassic.Previous studies have shown that magma intrusion and mineralization are closely related to the Beishan area.Beishan Mountains at Triassic belonged to a post-collisional geotecture environment.Under the action of post-collision intracontinental extension，massive granitic magma upwelled along the shear zone and provided thermal power and routes for the activation and migration of ore-forming materials，thus creating favorable conditions for large-scale metal mineral metallogenesis in this region.Qianhongquan gold deposit has similar metallogenic epoch and metallogenic geological background as those complex deposits in the southern part of the Beishan orogenic belt.Based on previous research results，it is believed that the Triassic was a period of large-scale metal deposits in Beishan area，and the post-orogenic extending stage was a favorable geotecture background for the occurrence of abundant metal minerals.These facts will constructively guide gold deposit metallogenic mechanism research and gold prospecting in Beishan Mountains，which must be highly valued by geological workers.
Gold ore fluid inclusions and S， H and O stable isotopes from -740~-820 m middle section of ore body VII in Xiadian gold deposit were measured to study the ore-forming fluid properties and sources.The fluid inclusions are mainly liquid rich inclusions， followed by gas rich inclusions and H2O-CO2 three-phase inclusions. The gas-liquid ratio is generally 10~15， and
The development of China’s mineral resources has gradually entered the depths，the difficulty of mining has increased significantly，and the safety risks have increased.At the same time，the ageing of China’s underground employees is serious and it is difficult to continue.The development of intelligent and even unmanned mining technology，reducing underground personnel，and improving production efficiency and safety are the inevitable choice and the only way for China’s deep resource extraction.At present，most of China’s metal mines have been mechanized and gradually developed toward intelligence.In order to build the country’s first underground unmanned mining demonstration area，the middle section of -630 m to -645 m was selected as the test stope in the Xishan mining area of the Sanshandao gold mine.The traditional mining method has a complicated mining process，and it is difficult to meet the work and scheduling of various unmanned equipment.Therefore，the continuous mining technology of the unmanned mining area in Sanshandao gold mine was studied.The design adopts downward medium-deep hole caving and subsequent filling mining method.The specific mining work of the mining method includes：The remote-controlled rock drill enters the rock-drilling tunnel in the section through the auxiliary ramp，and digs downward fan-shaped holes；The charge is filled with the detonating bomb unmanned filling system，the wireless detonation network and the remote control detonation system are built，realize remote initiation；Local fan forced ventilation is used for stope ventilation to ensure clear and visible equipment operating environment；Use unmanned scrapers to enter the stope for shoveling and loading of ore；After each mining room is completed，the filling work is carried out；After subsection mining is over，proceed to the next subsection.The unmanned continuous mining process covers the continuous unmanned operation process of each process of “digging-mining-transporting-filling-assisting”.This mining method can effectively guarantee the safe，efficient and continuous production and operation of multiple types of unmanned mining equipment，and the mine production capacity should be improved while safety of mine production is ensured，which will promote the future development of China’s mining intelligence.
In order to study the effect of joint roughness coefficient（JRC） on stress wave propagation and the mechanism of failure of rough joint rock specimens under stress wave action，a numerical model of particle flow code in a split Hopkinson pressure bar（SHPB） system was established by using PFC2D，a numerical analysis software based on discrete element method. Based on the existing SHPB physical test，the microcosmic parameters of joint rock specimens were demarcated. By comparing the waveforms of incidence，transmission and reflection generated by physical test and numerical simulation，the microscopic parameters were adjusted until the waveforms were basically the same，so that the correctness of the numerical model was verified. The numerical model was used to study the influence of JRC on stress wave propagation under low impact load and the microcosmic crack propagation and failure mechanism of joint rock specimens with different morphology under high impact load. In addition，the stress balance at both ends of the specimen under low impact load was analyzed by using the stress balance factor and the stress variation with time at the incident end and transmission end of the specimen. The typical stages of stress change at both ends of joint rock specimen and complete specimen in numerical impact test were compared and analyzed to explain the delayed effect of stress wave on joint surface and the effect of joint roughness on the increase of stress at the incident end. The results show that the presence of joint surface can reduce the transmission coefficient of stress wave，and the larger the JRC value of joint rock specimen is，the smaller the transmission coefficient is，and the stronger the reflected wave of the joint surface is，the more obvious the effect of stress growth slowing down at the incident end of the specimen is. Under impact load，the crack initiation occurs at the joint surface and spread rapidly to the whole part of the specimen，especially the end surface of the specimen，most of the cracks are formed in the post-peak stage，and tensile cracks are dominant. The rougher the joint surface is，the lower the dynamic strength is，the more easily the specimen is destroyed and the more cracks are produced.
As the shallow mineral resources exhausted，deep mining is the general trend for global mining engineering. Backfill method is widely used in metal mining engineering which control the mine stability. With the improvement of the method，the mechanical behavior of backfill is attracted extensive attention. This article analyzed backfill mechanical behavior based on the experimental test.Combined uniaxial compression tests with acoustic emission monitoring，backfill samples with pre-existing crack were tested.Five groups backfill samples were tested and all samples with strength within 35 MPa. Five groups sample with dips of 0°，30°，45°，60°，and 90°，represented five fractures distribution.The results show that backfill sample with 90°-dip fracture demonstrated more obvious brittleness and less plasticity than other samples.Acoustic emission signals could represent fractures initiation and development of backfill samples.Acoustic emission locations have their characteristics in five groups backfill samples. Initially，acoustic emission of backfill sample with 0°-dip fracture located near the pre-existing fracture，and then develop to the other parts of sample.While for backfill samples with other four dips fractures，acoustic emission mainly concentrated near the pre-existing fractures from initial stage to failure.For acoustic emission monitoring，some parameters could demonstrate the me-chanism of fractures propagation.In this article，three parameters were analyzed，they are AF，RA，and lg（AF/RA），respectively. AF represented the tensile fracture propagation，RA represented the shear fracture propagation，and lg（AF/RA） could reveal the overall fracture development.The process of backfill compression is divided into eight stages，namely crack closure，line elastic deformation，micro-crack initiation，stable micro-crack growth，micro-crack coalescence，unstable micro-crack growth，macro-crack coalescence，and failure. Finally，the results show that the dip of pre-existing crack has large influence to backfill deformation and failure according to these three parameter analysis. AE value of the backfill sample with 0°-dip fracture is high in whole deformation process，and RA value remains low and waves in small range. The change of AE and RA value showes shear and rupture in particles is not obvious，and initialed and developed fractures are major tensile.Based on this parameters changed，other four samples parameters values were analyzed，and backfill samples with 30°-dip and 45°-dip fracture are similar to backfill sample with 0°-dip fracture，and backfill samples with 60°-dip and 90°-dip fracture are different.Finally the research come to a conclusion that samples with small dips of pre-existing crack failed by tensile cracks，and samples with large dips of pre-existing crack failed by tensile-shear cracks.
With the increasing number of underground roadways built in high-intensity earthquake zones in western China，and ground motion loads will cause various earthquake damages in the roadways，this has aroused the attention of the academic community to the seismic resistance of the roadways，but there are few pressure arches in the academic community.The dynamic load response law of high altitude and its influencing factors were analyzed.Therefore，this paper studied the change law of pressure arch height under seismic dynamic load for deep horseshoe-shaped roadways.Taking the flood drainage roadway of Xiaomaliu tailing reservoir in Xichang，Sichuan Province as an example，based on
In the mining process of underground mines，the work of engineering geological investigation of the roadway is the necessarily for the rock mass stability evaluation. Through the mapped geometric parameters of the structural plane，a computer program was used to establish a three-dimensional model of the structural plane and the underground roadway to analyze the structural characteristics of rock mass. However，due to the complex rock mass conditions of the underground roadway，the limited exposure and variability of rock face orientation in roadways must be taken into account. Traditional methods for the mapping of structural planes such as scan-line mapping and window mapping are restricted by the complex environment of underground engineering that cannot be obtained accurate data. This would result in insufficient quantity and poor quality of the obtained structural plane data，which makes it impossible to accurately analyze the structural characteristics of rock mass in underground roadway. In order to accurately obtain the structural plane information of the underground roadway，3D laser scanning technology was used to research on the detection and identification of rock mass structural planes in underground mine. The work flow of the 3D laser scanning system and its principle，point cloud data processing，and structure plane information extraction was explained. Then，the 3D laser scanning and structural plane information extraction were carried out at the roadways of 1 430 m level，1 440 m level and 1 450 m level of the Dabaiyan area Ⅰ-51# ore cluster of Kafang Branch of Yunnan Tin Co.，Ltd. Finally，the structural plane data obtained by the traditional measurement methods and the 3D laser scanning measurement were compared and analyzed. The results show that the structural plane data obtained by the 3D laser scanning measurement method in underground mine is more abundant，comprehensive and accurate than traditional measurement methods. Using the characteristics of fast 3D laser scanning operation speed and wide scanning range can greatly reduce the working time of surveying personnel in the harsh environment of underground roadway，thereby improving the work efficiency of surveying personnel and ensuring work safety. In addition，the virtual point cloud data of the structural plane obtained by the 3D laser scanning can be directly generated by the post-processing software to directly generate the 3D model of the structural plane，thereby quickly interacting with other rock mass structure analysis software，reducing repeated modeling steps.3D laser scanning technology can provide an efficient method for the engineering geological investigation of rock mass structural plane in underground mine.
Filling pipeline wear system is a typical high-dimensional，nonlinear，strong coupling and multi-time-varying complex system.It is difficult to accurately predict the wear situation using traditional prediction methods.In order to overcome the poor applicability and insufficient prediction accuracy of traditional prediction models，and the defect of strong randomness in parameter selection and so on，this paper proposed a new method for predicting the wear risk of filling pipeline by combining the kernel principal component analysis （KPCA），improved particle swarm optimization （IPSO） and least squares support vector machine （LSSVM）.A comprehensive selection of 12 main influencing factors was used to establish the prediction index of wear risk of the filling pipeline.The KPCA method was used for feature extraction and dimensionality reduction of the influencing factors of the filling pipeline to eliminate redundant information between the data，so as to reduce the correlation between sample data and modeling accuracy impact.Established the corresponding LSSVM prediction model based on the dimensionality-reduced data，and used the IPSO algorithm with strong global search capability to optimize the model parameters to avoid the blindness of artificial parameter selection，thereby improving the model prediction accuracy and establishing KPCA-IPSO-LSSVM combined prediction model.Taking the filling system of Huangling County mining area as an example，combining the 80 sets of sample data measured in the field，MATLAB was used to train and predict the built model，and the prediction results were compared with the prediction results of the IPSO-LSSVM model，LSSVM model，and SVM model.For comparison，multi-error indicators were used to comprehensively analyze the prediction results of the four models.The research results show that the predicted value of the constructed model is basically consistent with the actual value curve.The KPCA method can effectively reduce the redundant information between the data.On the basis of retaining the original sample information to the maximum，five principal components containing 86.97% of the original information are extracted，it simplifies the calculation structure of the model.The prediction accuracy of the adopted IPSO-LSSVM model is 6.79%，the average relative error is 1.95%，and the judgment coefficient is 99.55%.Compared with other prediction models，the prediction model based on KPCA-IPSO-LSSVM has higher prediction accuracy and stronger generalization ability，which provides a more effective prediction method for the prediction of the wear risk of the filling pipeline，and provides a guiding basis for ensuring the smooth progress of the filling operation and the safe production of the mine.
With the development of economy and society，the national environmental protection policy has become increasingly strict.According to the requirements of relevant departments，the mine tailings pond is facing a gradual and comprehensive withdrawal.At present，the utilization and disposal of the tailings dumped in the tailing pond has become a practical problem that has to be solved.Considering the actual situation of the mine studied，the tailings stored in the tailings pond are all fine tailings with small particle size.If used this fine tailings as filling，there are problems such as poor fluidity and low strength of filling body.The chemical composition and particle size of the tailings was determine by X-ray fluorescence spectroscopy and laser particle size analysis.Orthogonal experiments and cement filling experiments were conducted to explore the influence of tailings slurry concentration，cementitious material content，the amount of admixture，and the proportion of fine tailings on the strength and diffusion of the backfill.By using range analysis and variance analysis，the order of importance of the influence of each factor was obtained，and the recommended ratio parameters were determined through multiple regression analysis.Finally，the microstructure of the filling body was further explored through the test results and SEM analysis.The results show that the order of importance of the factors affecting the strength of the filling body is the cementing material content，slurry concentration，admixture content，and the proportion of fine tailings.The order of importance of the factors affecting the diffusion is as follows：The proportion of fine tailings，the amount of additives，the slurry concentration and the amount of cementitious materials.The control variables can obtain the strength growth law of the filling body：Increasing the slurry concentration and the amount of cementitious material can increase the strength of the filling body；Within the appropriate amount，the strength of the filling body increases with the increase of the admixture；The content of tailings will have a more complex impact on the strength of the backfill.According to the regression formula，the recommended ratio parameters for the actual ore house filling are 70% slurry concentration，20% cementitious material content，1‰ admixture content，and 30% fine tailings content.Adding admixtures can make the hydration reaction more fully，thereby increasing its strength.The results show that the strength and fluidity of the fine tailings filling body can meet the requirements of the actual chamber filling.
At present，most of the researches on the thickening performance of tailings are macro researches，and the focus of the research is to improve the settlement performance parameters of mortar by using certain agents，technical means or methods. However，there is no micro research and no in-depth study on what causes the great difference in the thickening properties between different tailings. At present，there is no systematic study on the influence of density and particle size on solid flux and underflow concentration. This paper tries to analyze the main factors affecting the flocculation thickening effect by doing a large number of static sedimentation tests，and to study the quantitative relationship between the technical parameters of full tailing mortar thickening and the physical properties of tailings. Therefore，the particle size composition and density of the tailings of nine metal mines were measured first，and then the flocculation sedimentation tests of the whole tailings of these nine metal mines were carried out. The optimal pulp dilution concentration，underflow concentration，flocculant type，flocculant dosage and tailings throughput per unit area of the 9 typical mines were obtained. The results show that the underflow concentration of slurry，the change of slurry concentration and the amount of flocculant required for sedimentation test are only related to the particle size of tailings，and have nothing to do with the density of tailings. The coarser the particle size is，the higher the underflow concentration is，and the less flocculant dosage is required for the test. The larger the particle size and density of tailings are，the higher the solid flux is. Furthermore，the mathematical relationship between the factors was fitted by the dimensionless regression analysis method，and the relationship equation between the median particle size of tailings and underflow concentration was obtained，the relationship equation between the control particle size of tailings and the concentration change was obtained，and the relationship equation between the particle size，density，concentration and solid flux was obtained. Comparing the calculation results with the test results，it is found that the difference between the predicted value and the test value is very small，which proves that the derived relationship equation is convenient and feasible，and has a good application value.
Since 2013，with the implementation of the “Belt and Road” Initiative，the development and utilization of resources and the scale of engineering construction in cold regions along the way have been expanding.Research on the mechanical properties of frozen rocks in cold regions at home and abroad has developed rapidly，and many valuable academic results have been obtained.However，there is no paper that summarizes the hot topics and development trends of domestic and foreign research in recent years.In order to understand the research hotspots and development trends of rock mechanics under the freezing and thawing environment from 2013 to 2020，and to provide reference and innovation space for follow-up scholars in related research，bibliometric research was conducted in this paper.By selecting the search term of TS=（freeze-thaw OR freeze-thawing OR freezing and thawing OR freezing-thawing OR frozen-thawed） and TS=（rock OR rock mass） and SU=（freeze-thaw or freeze-thaw cycle） and SU=（rock or rock mass），the subject search was performed on the academic papers in the relevant direction included in the Web of Science foreign language database and the domestic CNKI database.CiteSpace cluster analysis selects the appropriate clustering threshold and pruning method（Pathfinder），and a visually intuitive domestic freeze-thaw rock mechanics research organization cooperation network， keyword co-occurrence network， and hot research evolution time zone view knowledge map was constructed through the visual analysis of the built-in software system of Institution，Keyword，and Timezone View functions.Through comprehensive statistical analysis results of papers and the clustering structure of the knowledge map，it is found that the research on freeze-thaw rock mechanics at home and abroad is in a rapid development stage.The participating countries and research results are increasing year by year，and the research status is hot.The distribution of core journals is relatively high.As a representative journal of the research direction of rock mechanics in China，14.8% of academic papers are included in Rock and Mechanics Engineering，Rock and Soil Mechanics，and Geotechnical Engineering，indicating that a series of innovations have emerged in domestic frozen rock research achievements.The distribution of core research institutions is obvious.The University of Chinese Academy of Sciences，Central South University，and Xi’an University of Science and Technology play a key role in the cooperative network structure of publishing institutions.However，the participation of enterprises and scientific research institutes in project research is relatively low，and it is difficult to give full play to “production，study and research” comprehensive advantages，a single research model will not be conducive to the development of domestic frozen rock mechanics.The research hotspots can be summarized as research on multi-scale mechanical damage characteristics of freeze-thaw rocks，research on fractured rock mass freeze-thaw damage mechanisms，rock freeze-thaw damage constitutive models and numerical simulation research.The multi-field coupling study of rock under freezing and thawing conditions and the engineering transformation of mature research results will be the focus of subsequent related research.
Ore yard is an indispensable part of most mines，and the precisely controll of its grade spatial distribution is the foundation of follow-up processes.The development and application of surveying technology provided technical guidance to the surveying and modeling of ore yard.Domestic and foreign scholars applied GPS RTK，3D laser scanning，GPR integration and unmanned aerial vehicle tilt photogrammetry to 3D modeling of ore yard. At the same time，grade distribution in ore body，production region and blasting muck yard was researched richly. But few scholars pay attention to grade distribution in ore yard，for the lacking of sample information to support the research of the spatial grade analysis of ore yard. The deeply application of grade on-line analyzer in mine production detection provided data sources for the modeling of ore yard’s grade model. Combined with the detecting real-time value of grade on-line analyzer，method of grade model constructing was proposed. 3D ore yard model was discretized. Ore yard was discretized as sub-segment in the length direction，and as sub-level in the cross section. Secondly，according to the spatial distance and ore flow velocity，the time gap between different locations when ore flow passed was calculated.Finally，turn the serialized data into 3D model of ore yard based on the time gap of ore flow. Then quantity and grade of each sub-segment and sub-level was analyzed. Based on 3D ore yard grade model，grade distribution was analyzed on the reclaimer’s working surface with the location and angle of claw.As the result，real-time grade was predicted. In order to verify the accuracy of ore yard grade model and reclaiming grade predicting method，grade data of MgO was contrasted between 4 shifts.Used hourly sampling test value as baseline，mean value and predictive value were contrasted. When used mean value as the reclaiming grade，the maximal hourly gap in 4 shifts is 13.87%，17.04%，15.65% and 12.54% respectively，and maximal shift average gap is 5.66%，9.41%，7.76% and 6.63% respectively. Meanwhile，when used predictive value as the reclaiming grade，the maximal hourly gap in 4 shifts is 2.93%，3.44%，3.50% and 3.16% respectively，and maximal shift average gap is 1.88%，1.98%，1.83% and 1.73% respectively. Contrastive analysis between mean value，test value and predictive value show that hourly gap is lower than 3.5%，and shift average gap is lower than 2%. The ore yard grade modeling and reclaiming grade predicting method is accurate and real-time，which improves the effect of grade control in mine.
The projection contour line of orebody is the basis of mine engineering layout and mining design. It is often used in business scenarios such as orebody structure analysis，model reconstruction，mine development design，mining plan formulation，etc.. Especially for model reconstruction，the accuracy of orebody contour directly affects the accuracy of reconstructed orebody model，and then affects the refined management of ore reserves and mining design. Therefore，it is of great significance to study the projection contour of orebody for the management of mine resources and reserves and production design.In order to solve the problems of complex orebody projection contour line generation，such as large amount of calculation and slow speed，an automatic generation method of complex orebody projection contours based on grid partition was proposed. The triangle mesh that constitutes the orebody model is projected to the designated plane by reducing the dimension to generate two-dimensional triangular patch set.Using self-adaptive rules to divide the grid into projection region，the triangular patches are stored in the corresponding grid cells，and the quad-tree method is used to establish the index relationship between triangular patches and the grid，and establish a two-dimensional index to the grid cells’ rows and columns. The grid unit is divided by using the method of adjacent element search，and the boundary rectangle of the element is used instead of the triangular surface of the internal element to participate in the operation. For triangular sheets spanning multiple grid elements in boundary elements，it is divided into boundary elements where triangular facets intersect with each other to reduce redundancy calculation. Finally，the projection contours is obtained by merging the set of recursive Boolean operations in the form of grid elements.In the research process，the CGAL：join algorithm was selected to conduct comparative experiments with this algorithm，and the number of triangles removed and the speed of solution were analyzed. CGAL：join algorithm does not screen the number of internal triangular patches，but this algorithm deals with the internal triangular patches，and the larger the search factor M，the less triangles are removed. Because CGAL：join algorithm does not filter out the internal triangular patches，the time consumption of CGAL：join algorithm is generally longer than that of this algorithm.With the increase of the number of patches，the time difference is more obvious.In this algorithm，the larger the search factor M，the more time-consuming，but the difference is small.The results show that the method improves the screening efficiency and solving speed，its convergence is stable，the speed is fast，and the projection contour line precision is high，which can meet the actual engineering requirements and application of mine，and has been applied in DIMINE digital mining software.
Rare earth elements are widely used in China’s industry and agriculture.They are important non renewable resources and are known as “industrial vitamins”.In recent years，with the rapid development of China’s economy and society，the demand for rare earth is also increasing.In pursuit of economic benefits，rare earth mining has left many abandoned rare earth mines.The serious damage of surface vegetation has led to serious environmental problems such as soil erosion and debris flow，which has gradually attracted the attention of the state and all walks of life.In order to understand the key factors that affect the governance effect of abandoned rare earth mines，provide scientific advice for the development of the governance of abandoned rare earth mines，this paper carried out research on the factors affecting the governance effect of abandoned rare earth mines. In the aspects of natural endowment，mining activities，environmental pollution，vulnerability of land resources，landscape ecology，treatment engineering，management technology and policy response，the influencing factors index system had been built to analyze treatment effect of abandoned rare earth mine.Based on the interpretative structural model （ISM），the direct influence relationship between indicators was analyzed，and the hierarchical structure of influencing factors was constructed.The influence of each index on the treatment effect of abandoned rare earth mine was analyzed from three aspects of impact factor，middle indirect influence factor and deep fundamental influence factor.Then，the relationship between the indicators had been put forward to build analytic hierarchy process model （ANP）.And the main index factors of abandoned rare earth mine governance were found by calculating the weight influencing factors.The results show that the index system of influencing factors on the treatment effect of abandoned rare earth mines can be divided into complex system with 10 levels of hierarchical structure，which can be divided into three levels：Direct influencing factors of surface layer，indirect influencing factors of intermediate layer and fundamental influencing factors of deep layer.Mining area，main mining methods，mining time， mining activities，area ratio of soil and water loss under landscape ecology，and treatment project accounted for more than 0.05，which were the main factors affecting the treatment effect of abandoned rare earth mines.Based on the research results，the tie line project and work supervision are located in the key position of the hierarchical structure model，connecting the preceding with the following，playing an important connectivity role in the governance work，which needs the management department to pay more attention to.The mining activities and landscape ecological criteria layer occupy the largest weight among all the criteria layers，so the regulatory authorities should strengthen the supervision of rare earth mining and land resources damage，do a good job in source control，and pay attention to the restoration of land resources in abandoned rare earth mining areas，so as to prevent the further deterioration of environmental problems of abandoned rare earth mines and accelerate the green development of abandoned rare earth mines.
In order to recover gold from solid waste efficiently，a combined beneficiation and metallurgical test was carried out on gold-bearing tailings.The results of chemical analysis show that the gold content in solid waste is 0.86 g/t.Process mineralogy showes that the main gold minerals are tellurite ore，tellurium-gold-silver ore and gold-bearing tellurium-silver ore，followed by natural gold and silver-gold ore.In the original ore sample，gold is mainly produced in the form of sulfide wrapped gold，accounting for 51.72%，followed by bare gold，accounting for 31.03%，a small amount of gold is produced in the form of quartz wrapped gold，accounting for 17.24%.The original ore sample was vibrated to the particle size of -0.074 mm accounted for 98.15%.According to chemical phase analysis，gold is still mainly produced in the form of sulfide wrapped gold，accounting for 50.00%，with little change.Part of gold is produced in the form of bare gold，accounting for 41.86%，and a small amount is produced in the form of quartz wrapped gold，accounting for 8.14%.It can be seen that grinding can obviously improve the leaching rate of gold.If gold is recovered by flotation，the recovery rate of gold can be increased.At the same time，it can also be seen that the recovery rate of gold is less than 50% by direct cyanidation leaching method，and the gold in the ore sample needs to be recovered by the combined process of concentration and smelting.The flotation gold concentrate pretreatment leaching process for gold concentrate should be adopted to recover gold.The closed circuit process of “one roughing-two sweeping-two cleaning” was adopted.Gold concentrate with the yield of 14.23%，gold grade of 5.21 g/t and gold recovery of 86.21% can be obtained.When the gold concentrate is grinded to -0.037 mm accounted for 70.12%，the leaching rate of direct cyanide gold is 41.60%.The main barrier effecting the gold leaching is that most gold is wrapped by pyrite and gold minerals are mainly tellurite，tellurite，gold-bearing silver tellurite，etc.The oxidizing roasting-leaching improved the leaching rate effectively.The suitable conditions for the oxidation roasting cyanidation leaching of gold concentrate are：The temperature of oxidation roasting is 750 ℃，the roasting time is 60 min，and the fineness of the roasting sand is -0.037 mm accounted for 85%，pulp concentration is 33%，pulp pH value is 10.5，sodium cyanide dosage is 10 kg/t，leaching time is 24 h.Under these conditions，the cyanide leaching rate is of gold is 73.76%，compared with the direct cyanide index of gold concentrate （cyanide leaching rate is 41.60%），the cyanide leaching rate of gold is increased by 32.16%.
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