The demand for cobalt metals has accelerated due to the increased use of cobalt in high-technology industries，thus the security supply of cobalt ore resources has attracted attention worldwide.Cobalt，as one of the critical metals，is in an acute shortage in China.The East Kunlun Orogen is a significant Au-Cu-Fe-Co-Ni-Pb-Zn polymetallic metallogenic belt in western China.The Tuolugou Co（Au） deposit has great reputation as the first large independent cobalt deposit discovered in the northwestern China，whereas the understanding of the metallogenic process of Co is controversial.By combining EPMA and EBSD analyses，together with the field investigation and detailed microscopic observation，the paper revealed the sedimentary exhalative mineralization and superimposed reworking process responsible for the formation of the Tuolugou deposit.The sedimentary exhalative mineralization formed the fine-grained pyrite（PyⅠ），and the superimposed reworking process consists of two mineralizing stages，i.e.，fine-grained pyrite （PyⅡ）+cobaltite+gersdorffite+siegenite+pyrrhotite+minor chalcopyrite stage and coarse-grained pyrite （PyⅢ）+native Au stage.The three generations of pyrite have different chemical compositions，of which PyⅠ has Co contents ranging from 0.03% to 4.86%，PyⅡ ranging from 0.38% to 2.74% and PyⅢ ranging from 0.03% to 0.58%.The obvious negative correlations of Co with Fe uncover that Co exists in the pyrite lattice by stoichiometric substitution of Fe.These results concluded that Co occurs as either independent minerals（e.g.，cobaltite，gersdorffite and siegenite） or cobaltiferous pyrite in the Tuolugou deposit.The EMPA mappings depict that pyrite has complicated textural and chemical compositions，which suggest that the composite pyrite grains were formed by fluid-mediated coupled dissolution-reprecipitation reactions according to the sharp contact boundaries，the distinct chemical compositions，and the consistent morphology and crystallographic orientation among different generations of pyrite in EBSD inverse maps.In combination with the previous work，it is deduced that both the sedimentary exhalative mineralization and subsequent reworking process contributed Co mineralization in the Tuolugou deposit.This study provides a useful guide for the Co mineral exploration and efficient metallurgy in the eastern Kunlun Orogenic Belt.
The Zhengchong gold deposit is a typical gold deposit in northeast Hunan.Its orebodies are controlled by NNE and NW trending faults and occur in Lengjiaxi Group with low metamorphism.The ore-forming age and the source of ore-forming materials are still controversial.In this study，by using the LA-（MC）-ICP-MS analysis method，in situ Rb-Sr dating of sericite in gold-bearing quartz vein and in situ S isotope analysis of pyrite were carried out to determine the ore-forming age and source of ore-forming materials，so as to clarify the genesis of the deposit.According to the ore-vein interpenetrating relationship of ore-veins and mineral paragenesis， the mineralization can be divided into three ore-forming stages，namely quartz-pyrite-gold stage，quartz-pyrite-arsenopyrite-polymetallic sulfide stage，quartz-calcite stage.Microscopic observation show that sericite in stage 1 and stage 2 had a close intergrow with pyrite/arsenopyrite.In situ Rb-Sr dating of sericite show that the ore-forming ages of stage 1 and stage 2 were （219.1±6.0）Ma and （215.8±7.7）Ma，respectively.Three kinds of pyrite were identified under the backscattering （BSE） image.The pyrite （Py1） in stage 1 is mainly eudedral and medium-coarse-grained，with δ34S ranging from -3.86‰ to 1.03‰.The pyrite （Py2） in stage 2 has an euhedral，mesocoarse-grained structure and an obvious core-rim zonation.The core （Py2a） is uniform in the BSE image with δ34S ranging from -1.43‰ to 1.51‰，while the edge （Py2b） has an obvious oscillation zone and other sulfide （galena） inclusions，with δ34S ranging from -3.21‰ to 1.95‰.The δ34S values （-3.85‰~1.95‰） of the three types of pyrite are close to 0 and the negative value moves to positive value，indicating that deep magmatic （or mantle-derived） materials may be the main source of ore-forming materials in Zhengchong gold deposit，and a small amount of stratigraphic material is involved in the mineralization.Based on the geological characteristics，metallogenic chronology and sulfur isotope geochemistry，We believe that the Zhengchong gold deposit was formed in the Indosinian intracontinental orogenic environment and related to deep magmatic activity.
The Xiong’ershan ore concentration area is located in the middle eastern part of the Qinling orogenic belt. Multi-stage tectonic activity leads to regional multi-level faults，among which the first-grade fault is a deep fault with multi-stage activity and structural inheritance characteristics，which controls the distribution of original source of ore-forming materials and regional mineralization.The second-grade fault controls the distribution of metallogenic belts.The third and fourth grade faults are the main ore hosting faults.The regional extension and tectonic extension in Yanshanian period led to extensive magmatic activities，which provided important material and energy sources for mineralization.The interaction between the Yanshanian mantle and the crust led to large-scale magmatic activities and tectonic movement，thus forming a large number of precious and nonferrous metal deposits of different stages and scales in the area.The Dongcaogou deposit is a new gold-silver deposit discovered in the Xiong’ershan ore concentration area in recent years，which is still in the stage of exploration and development.Field structural analysis shows that the orebody of the Dongcaogou deposit is strictly controlled by faults.From the end of Indosinia to the early Yanshanian，the structure in the near EW direction is dominant in this region，with minor NNE-near SN direction faults.Five stages of tectonic activities in the deposit were identified in this study，and their sequence and tectonic stress field are as follows：The first stage tectonic stress field is near SN compression，the second stage tectonic stress field is near EW compression，the third stage tectonic stress field is NW compression，these three stages fault are pre-mineralization structures，the fourth stage tectonic stress field is NNE compression，which is a fault structure in the syn-mineralization，and the late stage tectonic stress field is converted into extension due to stress relaxation.The fifth stage tectonic stress field is NE compression，which is a post-mineralization fault.According to the occurrence，kinematics and deformation characteristics，the ore-control faults can be divided into structural fracture zone （strong structural deformation zone） and steep fault.The study of the time-space relationship between structure and mineralization shows that the ore-controlling faults in the early and late ore-forming stages have obviously difference in structural characteristics.In the early ore-forming stage （late Indosinian early Yanshanian） ，the ore-controlling faults are compressive faults and show obvious ductile brittle deformation where S-C structures and tectonic schistosity zones are developed，reflecting a tectonic stress field of nearly S-N compression. In the late ore forming stage （middle and late Yanshanian） ，the ore-controlling faults are characterized by tensile faults and brittle deformation，and the ore veins are characterized by typical expansive filling veins，which suggested that tectonic stress field is nearly E-W oriented extension.The ore-controlling faults in different directions in the area are multi-directional conjugate fault systems formed under the near S-N direction compression，and the secondary faults derived from them.The assembly patterns of the compound conjugate fault system control the spatial distribution and pattern of ore bodies in the Dongcaogou Au-Ag deposit.
Yunnan-Guizhou-Guangxi region，one of the most important gold mineralization areas in China，hosts many high temperature magmatic hydrothermal gold （copper） deposits，such as Pulang gold-bearing porphyry copper deposit，Beiya and Yaoan gold deposits，and low temperature hydrothermal gold deposits，namely carlin-type gold deposit，such as Badu，Nibao and Shuiyindong gold deposits.A lot of chemical studies of minerals，such as magnetite，pyrite and apatite have been carried out，and the abundant mineralogical geochemical data of trace elements in situ have been accumulated. However，the source materials and formation process of the deposits are still be disputed.Therefore，further statistical and comparative analyses of these data may provide a basis for revealing metallogenic information and guiding prospecting exploration.Due to the unique chemical characteristics，apatite can better preserve the important information of magma-hydrothermal evolution process，and is often used to define the fine metallogenic process of ore deposits.In this paper，the trace elements of hydrothermal apatite in high-temperature magma-hydrothermal deposits（Yao’an gold deposit and Pulang gold-bearing copper deposit） and low-temperature carlin-type gold deposits（Badu and Nibao gold deposits） have been collected and analyzed.It is found that the apatite in the high-temperature alkali-rich porphyry gold （copper） deposit is characterized by automorphic shape，high F and Cl contents，enriched LREE，and depleted HREE.In contrast，the apatite in the low-temperature carlin-type gold deposits is characterized by hypautomorphic and xenomorphic shapes，low F and Cl contents，enriched MREE.In addition，the δEu-δCe binary diagram and chondrite-normalized REE patterns revealed that the carlin-type gold deposits have higher oxygen fugacity than magmatic hydrothermal copper and gold deposits.Combined with the geochemical analysis of rare earth elements of stibnite in the Youjiang Basin，it is concluded that the enrichment characteristics of MREE in apatite（including fluorite and calcite） indicate that the low-temperature mineralizing fluid may be related to the special basin basement rock. In conclusion，apatite has unique geochemical characteristics in high temperature-medium and low temperature gold deposits，which can effectively reveal the type of ore deposit and the evolution process of ore-forming fluid.
The Xintianling deposit is one of the largest skarn-type scheelite deposits in South China，and its mineralization has undergone complex magmatic and hydrothermal processes.Taking the skarn garnet in the Xintianling deposit as the research object，the U-Pb dating，in-situ major and trace element analysis of garnet were carried out by EPMA and LA-ICP-MS in-situ micro-area testing techniques.The U-Pb dating reveals that the age of ore-related garnet in Xintianling deposit is ca.（159.5±3.0）Ma，which is consistent with that of the fine-grained porphyritic biotite granite（164~157 Ma）of the Qitianling rock mass，indicating that the Xintianling tungsten mineraliztion is closely related to the Qitianling rock mass.Based on the mineral assemblages and backscattering images，it is determined that there are three generations of garnet in the Xintianling tungsten deposit.According to the structural characteristics of garnets in the backscattered images，the garnets in the Xintianling deposit can be divided into three generations，namely，the early stage dark garnet（Grt1），the middle stage garnet with obvious oscillation zone（Grt2） and the late stage bright garnet （Grt3）.Among them，Grt2 can be divided into Grt2-1 with oscillatory zones and Grt2-2 with thick oscillatory zones.Grt1，Grt2-1and Grt3 show the left-skewed REE patterns with LREE depleted and HREE enrichment.Grt1 has an obvious negative Eu anomaly，Grt2-1 has a weak Eu negative anomaly，and Grt3 has a weak Eu negative anomaly.In contrast，Grt2-2 has a “hump-type” REE pattern with LREE enrichment and HREE depleted，and the weak Eu positive anomaly.From Grt1 to Grt3，the content of Mn in garnet showes a trend of first decreasing and then rising，and the W content in Grt3 is higher than Grt2 but lower than Grt1.These results suggest that the Xintianling deposit has experienced multiple hydrothermal processes，and the oxygen fugacity and temperature of the ore fluid first increas and then decreases，and the pressure pH value first decreases and then increases during the ore-forming processes.Combined with the variations of W content in garnet from different mineralization stages，it is considered that the mineralization of tungsten in the Xintianling deposit mainly occurs in the retrograde metamorphic stage，and undergoes the process of dissolution-reprecipitation in the late retrograde metamorphic stage.
It is very important to study the lateral trending regularity of orebodies for metallogenic prediction，especially the factors controlling the lateral direction.However，previous studies mostly focused on orebodies controlled by faults，and regularity of orebodies controlled by stratum remains poorly understood. The Darongxi scheelite deposit in Anhua，Hunan Province is the most economically important scheelite deposit in the Au-Sb-W metallogenic belt in western Hunan，the historical mining and current reserves are 38 146 t WO3. This deposit occurs in Sinian Nantuo sandstone in the outer contact zone of the Dashenshan rock mass.The thickness of four scheelite orebodies in the deposit is 1.12~5.96 m，and the grade is 0.12%~1.02% WO3，which is similar to the occurrence wall rock of the Sinian Nantuo sandstone.The lateral trending regularity of the orebodies is still unclear，and the genesis of this deposit has been controversial.Based on comprehensive analysis of statistics，visualization and analysis on a large number of original basic data during the development and utilization period of the Darongxi scheelite deposit and 1 997 scheelite samples from 9 middle sections，the lateral trending regularity of orebodies was studied，and the mineralization process of Darongxi scheelite deposit and its relationship with Dashenshan rock mass were discussed. It is considered that the pitch direction of orebody is NE （42°） and it is controlled by Dashenshan rock mass.The western boundary of the scheelite enrichment area shows a similar shape to that of the Dashenshan rock mass.The slope at the west boundary is more disordered，while those at the east boundary fall off a cliff from ≥0.4% in the west of the boundary to <0.2% in the east.Moreover，the eastern boundary of the enriched orebodies is more than 200 meters away from the Dashenshan rock mass.The ore-forming materials of the Darongxi scheelite deposit are considered to be mainly derived from the sandstone of Nantuo Formation，and the Dashenshan rock mass provides a thermal and dynamic field for the activation，migration and re-enrichment of ore-forming materials.Combined with previous research，Jieshan area and Baishaxi area located respectively in north and in south of the Dashenshan rock mass are considered to have a good metallogenic prospect and suggested to be prospected for concealed orebodies in deep，because they are located in the thermal field of the Dashenshan rock and have similar metellogenic conditions wtih Darongxi scheelite deposit.
Kuzigan alkaline intrusive complex is the largest Cenozoic alkaline complex in the Taxkorgan area of West Kunlun.In recent years，the research on the Kuzigan alkaline complex has mainly focused on the formation age of the rock mass and the source of magmatic materials，but little research has been done on its rare earth mineralization characteristics.Based on the geological background and petrochemical characteristics of Kuzigan complex，the metallogenic characteristics of this type of rare earth ore in Kuzigan area were discussed by means of field investigation，microscopic identification and main trace element analysis.Three samples were taken from aegirine syenite and one contrast sample was taken from syenogranite.The results show that the total rare earth content of all kinds of rocks in the alkali metasomatic rare earth ore of Kuzigan is rich，mainly manifested as Ce and Y enrichment，and positively correlated with F.The REE content of syenite varies from 888.05×10-6 to 1 320.17×10-6，and it is enriched in light rare earth elements（LREE/HREE=13.54~19.65）.The curves in the REE chondrite normalized diagram is generally right-leaning，and the differentiation degree of LREE and HREE is not large as a whole.No obvious anomalies of Eu and Ce are found，which has the common characteristics of alkaline syenite.The range of LREE fractionation parameter （La/Sm）N is 3.80 to 26.75.The HREE fractionation degree parameter （Gd/Yb）N varies from 2.94 to 7.98，indicating that the syenite has slight fractionation on both light and heavy rare earths，but the fractionation degree of light rare earth is greater than that of heavy rare earth.The ore-bearing rock of rare earth ore（mineralization） in the Kuzigan alkaline complex is medium-grained aegirine syenite，which contains accessory minerals such as fluorite，apatite and monazite，and is located near the internal contact zone with medium-grained quartz syenite，the two are in gradual contact.The Kuzigan alkaline complex has high REE content and strong LREE enrichment，which is mainly characterized by enrichment of light rare earth elements such as Ce and Y，and is positively correlated with F.It has the prospect of finding alkaline metasomatic rare earth deposits，and should focus on strong potassic，aegirine and carbonate alteration zones.
The mining industry provides an important material basis for modernization and has become the basic industry for China’s economic construction.In order to promote the high-quality development of mining industry，the construction of green mines is the only way for sustainable development.There are studies on the evaluation of green mine construction，which mainly focus on the content analysis method and case study method，but rarely from the perspective of policy design，while the government is also an important subject to promote green mine construction.In order to improve the adaptability and scientificity of the policies，it is necessary to conduct a systematic evaluation of China’s green mine construction policies.Therefore，this study quantitatively evaluated and assessed the existing green mine construction policies in China，identified the deviations and shortcomings of the existing policies and proposed optimization strategies，which is of great theoretical and practical significance for the development and improvement of green mine policies in the new era.Unlike subjective evaluation methods such as expert scoring，the study analyzed the content of 193 green mine construction policies in China between 2005 and 2021 through social network analysis and text mining，extracted important subject terms，and build a framework for evaluating green mine construction policies on this basis.39 of these policies were selected as samples （13 policies at the central level and 26 policies at the local level）.The Policy Consistency Index Model （PMC），an important modeling method for policy research analysis，was used for quantitative evaluation and comparative analysis.The study found that China’s green mine construction policies are reasonable，but there are still some problems that need to be improved.Among the 39 selected Chinese green mine construction policy texts，8 of them are excellent，31 are acceptable，and there are no perfect and poor policies，while the central government’s policies generally score higher than local governments.At the central and local levels，there are common problems in green mine construction，including the scope of regulation and implementation agencies are small，economic benefits，tourism aspects，long-term planning，talent incentives，laws and regulations need to be improved.At the regional level，there are differences in green mine construction policies，including the lack of effective supervision in the central region，the lack of binding in the northeast region，and the need to improve the policy areas in the eastern and western regions.The research results provide a reference basis for the formulation of green mine related policies in China，and also provide new ideas and methods for the evaluation of green mine construction policies.
The construction of China-Pakistan Economic Corridor is moving toward high-quality development，and strengthening the trade of mineral products between China and Pakistan is also one of the important contents.Pakistan has good metallogenic conditions and relatively abundant resource reserves such as metal ores.Analyzing the competitive and complementary trade of mineral products between China and Pakistan in order to grasp the new direction of trade cooperation can provide new ideas to solve the problem of tightening mineral resource constraints in China.Based on the trade data in the UN COMTRADE database from 2005 to 2021，this paper measures the relative trade advantage index（RTA） and the bilateral comprehensive complementarity coef-ficient（OBC） to explore the competitiveness and complementarity of China-Pakistan mineral products trade based on the description of the development status and trade structure of bilateral mineral products trade between China and Pakistan，respectively.The results show that the development of China-Pakistan mineral trade is stable，but the trade structures of both sides differ greatly.The mineral products in which China and Pakistan each have trade advantages are different，and Pakistan has a larger number of mineral products with relative trade advantages，and the country mainly takes advantage of the metal mineral category，while China takes advantage of oil and gas products.In general，the competitiveness of China-Pakistan mineral trade is weak，and in the long run，China and Pakistan will form a complementary relationship，mainly focusing on metal ores，refined oil products and oil derivatives，etc.mineral products category.The study finds that China and Pakistan have great potential for cooperation in mineral trade，which can，to a certain extent，provide a new way to alleviate the contradiction between supply and demand of mineral products in China.In the future，China should firmly orient its policies and make full use of the complementary relationship to continue to maintain and develop its mineral products trade exchanges with Pakistan and seek breakthroughs in industrial cooperation and other aspects.
With the upgrading of mine production modes and the renewal of business philosophy，the problems that commonly exist in mining enterprises，such as low accuracy in manual calculation of ore blending，large fluctuations in ore grade，unbalanced ore quantities，and fragmentation of production data management，have become more and more obvious.Starting from the blending and production data management of ore management work，the mathematical model of large homogenized joint ore blending was established based on the theory of large homogenized joint ore blending technology and the ant colony-ant cycle algorithm model. The integrated management method of production data integration and sharing was proposed based on the large homogenized joint ore blending technology route and the mine on-site situation，summarizing the process，key data，and hierarchical linkage relationship.A large homogenized joint ore blending and production data integration and sharing system was constructed based on the ant colony-ant cycle model.Firstly，integrating the multi-stage ore blending in the mining site，stockpile，and processing plant，optimizing the blending quantity and ore grade from a global perspective，proposing the theory of a large homogenized joint ore blending technology，and establishing a large homogenized joint ore blending function according to the actual blending.Secondly，using the ant colony-ant cycle algorithm as the modeling framework of the blending model，establishing the mathematical model of large homogenized ore blending based on the large homogenized transformation，taking the large homogenized cycle as the number of iterations，and continuously adjusting the blending quality through the automatic blending order output from the model in the producing cycle. Finally，based on the ASP.NET low-code development platform，the B/S framework，and SQL Server database technology，big data charting combined with analysis technology and integrated data interface technology were introduced to develop a large homogenized joint ore blending and production data integration and sharing system.According to the application of the system at Dabaoshan polymetallic mine，the results show that after the system has been put into use，the whole process of mine ore blending and production has been systematized and streamlined，compared with the original ore blending method，the ore grade has been stabilized and balanced，the comprehensive recovery rate has been initially increased by 0.8%，the fluctuation range of the ore grade has been controlled to not exceed ±10%，and the mine management level and mineral product quality have been improved.
With the rapid development of unmanned driving technology，the driverless vehicles on the road have been widely used，which has laid a solid foundation for the fully unmanned mine.Especially for un-derground operation equipment，the roadway environment has the characteristics of closedness，irregular driving area，and difficulty in environmental perception，which makes the mobile equipment of underground manual driving inefficient and frequent accidents.So in a chaotic，irregular and dynamic environment，a safe and efficient autonomous navigation system is essential.The traditional autonomous navigation of underground mobile equipment mainly relies on pre-established static maps to make global path planning，then directly hands over the global path to control model，which makes it impossible to update the map in time when encountering sudden obstacles，resulting in oscillating trajectories and crooked paths.In order to solve the above problems，this article proposed the improved TEB （Time Elastic Band） local path planning to quickly update the path by combining global planning and local planning on the basis of mapping and navigation.In order to adapt the underground roadway environment， add target point constraints，urgency constraints，end smoothing constraints and energy consumption constraints，the nonlinear optimization problem can be iteratively solved through the G2O graph optimization framework to obtain a suboptimal solution that meets the requirements，the programming speed is within 100 ms.By simulating the dual-lane collision-free，dual-lane oncoming traffic，dynamic crossing scene，according to the principle of underground driving，the improved TEB algorithm produces a more feasible trajectory，which effectively shortens the path length，reduces the number of turns and stops，especially the path smoothness at the corner，and the operating efficiency is higher than the traditional TEB path planning algorithm.The average path generation value before the improvement was 23.09，and the average path generation value after the improvement was 10.19，which decreased the overall generation value by 55.87%.Finally，the unmanned vehicle experimental platform is used to build random obstacles in the underground roadway scene according to the 9∶1 scale，and the feasibility of the algorithm is verified in the dynamic cross environment，which can satisfy the safe and efficient driving of underground mobile equipment in the roadway.
In view of the difficulties in collecting structural information of deep high-steep rock mass，the cumbersome data acquisition and the operation of personnel in high-risk environment，the contact measurement method has been unable to meet the requirements of collecting structural information of rock mass.Therefore， the chamber face of +650 m level unloading station of Jinchuan No.2 mine was taken as the research object，the 3D laser scanner was used to obtain its surface point cloud data set，and the point cloud data was denoised and spliced.After processing，the information parameters of rock mass structure were extracted，and the reliability of the data was verified by checking algorithm and geological survey results.The results show that：（1）Through rapid processing of high-precision scanning data，the occurrence information of structural plane can be obtained when the control point is known and the control point is unknown，which reduces the risk of personnel acquiring structural plane information.（2）The least square algorithm was used to calculate the attitude，the approximate parallel structural plane group spacing algorithm was used to calculate the spacing，and the measured structural plane attitude was compared with the extracted structural plane information.It is known that the inclination and inclination errors are within ±6°，and the spacing errors are within ±0.03 m，which verifies the reliability of the extracted data.（3）The method proposed in this paper was applied to the extraction of the occurrence of the structural plane of the chamber face of the +650 m level unloading station in Jinchuan No.2 mine，and the occurrence information of the structural plane is effectively recognized.This research work not only avoids the danger，but also improves the accuracy and efficiency.
In order to study the crushing characteristics of ore （siliceous rock） in a mine under quasi-static loading，a crushing model of ore particle group was established by using Tavares crushing model on the basis of cylinder loading test，and the crushing characteristics of cylinder loading test and crushing simulation analysis were compared and analyzed.The results show that：（1） The breakage of ore particle group can be divided into three stages.In the tight stage，the void fraction of ore group is decreasing，and the breakage process of ore particle group basically does not occur.In the crushing stage，the void fraction further decreases，the stress on the contact points between ore increases，and some ore begin to break.In the agglomerating stage，the stress of ore particle group will increase rapidly，a large number of fine powder particles will be produced，and the agglomeration phenomenon will occur.（2） When the maximum loading pressure is 400 kN，with the decrease of the feeding particle size of ore with narrow particle size （2 mm range），the higher the proportion of small particles after crushing，the proportion of crushed ore of -6 mm under different particle sizes of -18+16 mm，-16+14 mm and -14+12 mm is 25.63%，29.45% and 33.46%，respectively.（3） The effectiveness of the Tavares model is verified by the comparison between simulation and experiment，and the simulation parameters of ore in a mine are calibrated，which provides a new method for the simulation of ore particle crushing，and the research results provide a new idea for the subsequent design of crusher.
In order to improve the utilization rate of blastholes in small section tunnels in a tin mine in Yunnan Province and reduce the unit consumption of explosives，after analysis，it is determined that the four factors of the charge amount，the distance between the charge hole and the empty hole，the hole diameter and the filling length are the test factors.The blast hole utilization rate and the cavity volume are the test indicators，and each factor takes 3 levels.Using the method of repeated orthogonal experiments，the effects of four different factors，namely，the charge amount，the distance between the charge hole and the empty hole，the hole diameter and the packing length，on the blasting hole utilization rate and the cavity volume were studied through the range analysis and variance analysis.The significance of the influence of each test index determine the optimal com-bination of test factors.The research results show that in the range analysis，the distance between the charge hole and the empty hole has the greatest influence on the utilization rate of the undercut blasting hole，followed by the hole diameter，the charge amount is smaller，and the filling length has the least influence. The hole diameter has the largest impact on the groove volume，the distance between the charging hole and the empty hole is second，the packing length is smaller，and the charging amount has the smallest influence.In the variance analysis，the distance between the charge hole and the empty hole has a very significant effect on the blast hole utilization rate，the hole diameter has a significant effect on the blast hole utilization rate，and the charge amount and packing length have no significant effect on the blast hole utilization rate.The hole diameter has a very significant influence on the volume of the cavity，the distance between the charging hole and the empty hole has a significant effect on the volume of the cavity，and the significant effect of the packing length on the volume of the cavity is slightly weaker than the distance between the charging hole and the empty hole.The amount has the least significant effect on the cavity volume.Therefore，for small section roadway excavation，when the hole diameter is 70 mm，the distance between the charge hole and the empty hole is 10 cm，the charge amount is 3 kg，and the mud filling length is 20 cm，the undercut can achieve excellent blasting effect.After several on-site roadway excavation tests，the blasthole utilization rate can be increased from 80% to more than 93%.
In recent years，with the continuous depletion of shallow mineral resources，there are many theoretical and practical studies on the recovery and utilization of sulfide ores in cyanide tailings.However，the existence of floatable gangue will hinder the recovery of sulfide ore in cyanide tailings.Therefore，it is very important to find out the adsorption mechanism of CN- on the surface of gangue minerals and the change of surface wettability to identify the cause of low flotation recovery of cyanide tailings.In this paper，three typical gangue minerals，quartz，feldspar and calcite，were used as adsorbent，and NaCN was used as adsorbent.The influence of adsorption time and amount of adsorbent on the adsorption effect of CN- were investigated.At the same time，the wettability difference before and after the adsorption of CN- on the surface of gangue minerals was analyzed by using the contact angle detection method of solid droplet，and the adsorption kinetic model was fitted for the adsorption results.The results show that quartz，feldspar and calcite exhibit different degrees of adsorption and selectivity for CN-.When the mineral dosage was 5 g and the contact time was 12 h，the adsorption rate of CN- tend to be stable.At this time，the adsorption rates of quartz，feldspar and calcite for CN- are 43.9%，58.0% and 43.6%，respectively.Through kinetic study，it is found that the adsorption of CN- by quartz and feldspar is mainly physical adsorption.There is binding adsorption between CN- and calcite.Finally，according to the contact angle detection，the adsorption of CN- resulted in the enhancement of the surface hydrophilicity of gangue minerals，and the surface contact angles of quartz，feldspar and calcite decreased from 38.5°，15.6° and 35.4° to 18.6°，14.4° and 20.6°.After the action of SBX flotation reagent，the surface contact angle of gangue minerals increase，but still showes hydrophilic properties.It shows that cyanidation will not cause the following flotation of non-target minerals when recovering sulfide ores from cyanide tailings flotation，which provides theoretical guidance for achieving efficient separation and flotation of metal sulfide ores in cyanide tailings.
The leaching agent cyanide has been on the verge of elimination due to its great harm to the environment and human health.The non-cyanide agent thiocyanate as an efficient and environmentally friendly gold leaching agent has become the object of research by scholars both domestic and foreign.However，the recovery methods from thiocyanate leachate are less studied，and there are problems with low efficiency and high cost of gold recovery.Therefore，it is urgent to find a highly productive，low-cost，and simple method to recover gold from leaching solution efficiently.On the basis of the above problems，ammonium thiocyanate was used for the leaching test of bio-oxidized slag from a difficult gold concentrate，and recovered gold from the leaching solution by electrodeposition.The single factor method was used to study the influence of various factors on the gold deposition rate.The results show that the self-made electrode with a large surface area，good corrosion resistance，and high metal deposition efficiency is an excellent cathode.The graphite rods with good conductivity，not involved in the reaction process，reused，is a good choice for anode materials.Stainless steel rods are not suitable as electrode materials due to their susceptibility to corrosion.Under the conditions of electrode spacing of 10 mm，cell voltage of 4 V，solution pH value of 12，and solution temperature of 35 ℃，using a graphite rod as an anode and a self-made electrode as a cathode，the gold deposition rate can reach 98.95%.The interaction between tank voltage，solution pH value，and solution temperature and the effect on gold deposition rate were investigated by response surface methodology，and the electrodeposition gold response surface regression model was established.The P value and mismatch value of the model are within a reasonable range，and the predicted value and actual value of the gold deposition rate basically fell in a straight line，shows that the model fits well and is highly reliable.The correlation between the test factors and the gold deposition rate can be described.The final results show that the degree of each factor on the gold deposition rate is cell voltage>solution pH value>solution temperature，among them，the interaction between cell voltage and solution pH value is the most significant，and the interaction between solution pH value and solution temperature is the least significant.Under the optimal conditions of cell voltage 4.10 volts，solution pH value of 12.40，and solution temperature of 39.58 ℃，the predicted value of the model is 99.06%，and the experimental average value is 99.04%.The two results are remarkably close，which proves that the model can accurately analyze and predict the gold deposition rate.This study further improves the theoretical system of thiocyanate gold extraction process.
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