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    25 March 2019, Volume 48 Issue 03
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    Study Status and Direction of Orepass Existing Problems in Metal Mine
    LU Zeng-Xiang, MA Chi, CAO Peng, MA Qiang-Ying
    2019, 48(03):  1-9. 
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    Phenomenons of orepass blockage phenomenon and sidewall deformation and destruction of orepass occurs frequently during the application process of orepass，they are becoming the important influence factors of safe and efficient production of mines.Existing problems of orepass is summarized as two major problems of blockage and sidewall stability，the study status and existing problems of orepass are analyzed and summarized.The blockage phenomenon of orepass is manifested in the suspension of materials flow during the process of oredrawing at the bottom of orepass.Sidewall stability phenomenon is mainly manifested in deformation，instability and collapse of sidewall of orepass.The study results show that:①main reasons of orepass blockage can be summarized as the matching relationship among ore moisture content，powder ore content，oredrawing funnel angle，height and time of ore storage，ore-rock block size and orepass diameter，large blocks produced by support structure falling off and sidewall surrounding rock collapsing，and the existing problems in operation and management of orepass；②main reasons of sidewall deformation and destruction of orepass can be described as particle size distribution and physical and mechanical properties of ores or waste rocks，geological characteristics and stress field features of the surrounding rock of orepass engineering，orepass structure，and sidewall support strength and their mutual relationship；③the fundamental reason of deformation and destruction caused by the impact，shear and friction damage of orepass sidewall，which caused by the force action produced by the movement of ores or waste rocks in orepass and the contact of ores or waste rocks with orepass sidewall；④human destruction of orepass sidewall is intensified by blasting dredging after orepass blockage and excavation blasting near orepass.Based on the above discussion results，the study directions of orepass existing problems as followings:①studying the relationship between the influence factors of orepass blockage，establishing the relevant mathematical models，discussing the design criteria of structure and related dimensions of orepass，so as to prevent orepass blockage；②revealing the movement regularity of materials in orepass and the mechanism of mechanical action of materials on orepass sidewall，improving structure and support model of orepass，so as to solve the existing problems of orepass stability fundamentally；③studying and developing the stress releasing technique and engineering support technique under high stress environment，are the main study directions of solving the stress crack destruction problem of orepass sidewall；④orepass blockage can be prevented from aspects of design，application and management，and non-blasting dredging technique for orepass blockage can be studied，so as to reduce blasting damage to orepass sidewall.
    Study Progress in Risk Analysis and Monitoring and Early-warning Technique of Shafts under Service for Deep Mining
    SONG Chao-Yang
    2019, 48(03):  10-20. 
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    The exploitation of deeply-buried resources is one of the important trends of deep exploration in China，shafts under service are the only way to enter the deep formation.Whereas，due to being constructed in strata and multi-facies geologic bodies characterized by location difference and complex service condition，shafts are facing increasing risk threatening their safety service.Therefore，risk analysis and monitoring and early-warning of shafts under service has been becoming a problem demanding prompt solution.Through the analysis of study progress and existing problems of risk analysis and monitoring and early-warning technique of shafts under service for deep mining in China，in order to achieve the ultimate aim of ensuring the safety service of shafts，based on the multi-scale and multi-source disaster synergism mechanism，shaft deformation instability theory，engineering risk evaluation and identification and monitoring and early-warning technique，and through rational reference and absorption of other underground engineering dynamic disaster prevention and control study results，the study ideal of multi-scale and multi-source monitoring and warning is proposed，besides that，key scientific problems and main study directions are summarized.Aiming at the stress source，corrosion source and physical property source that affect the safety service of shafts，for the shaft cracking，corrosion，deflection and other multi-source risk disasters，under the scale of “region-mining area-shafts-key sections”，the four key scientific problems should be further studied as followings:①the coupling relationship of regional stratum stress-energy-physical parameters and its spatiotemporal evolution under mining disturbance and multi-field coupling synergetic disaster mechanism；②intelligent judgment and early-warning theory of multi-parameter precursor information of shaft risk disaster in service；③multi-scale and multi-source precursory information collection and information cluster multi-network transmission technique system；④evaluation and identification method and early-warning model of shaft risk disaster in service.Based on further study of the above scientific problems，it is help for the formation of new evaluation model of shaft safety service status based on on-line monitoring，intelligent evaluation and identification，accurate early-warning of shaft safety risk in service，so as to provide theoretical and technical support for structural security management and intelligent service of the shafts in service in China.
    Situation and Research Development of Recovery Valuable Metals in Zinc Dust and Residue
    WANG Chao, GUO Yu-Feng, YANG Ling-Zhi, CHEN Feng
    2019, 48(03):  21-29. 
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    In order to promote the development of valuable metal recycling technology in zinc dust and residue, two types of typical secondary zinc resources, such as electric furnace dust and zinc leaching residue, which are abundant resources and rich in zinc ferrite, were reviewed based on the principle of comprehensive utilization, technical routes and utilization effects. It is pointed out that the mineral phase reconstitution is an effective method to realize the comprehensive utilization of electric furnace dust and zinc leaching residue. The main valuable components of electric furnace dust are zinc and iron. After the mineral phase is reconstituted, the zinc component should be separated by mineral separation. The remaining products should be returned to the iron making process for recycling in the steel plant; The main valuable components in zinc leaching residue are zinc, iron, gallium, indium, silver, etc. After the mineral phase reconstruction treatment, according to the elemental trend, a combination method of mineral processing and wet extraction is adopted, and achieve the comprehensive recovery of valuable elements without the secondary pollution.
    Review on Research and Application of Fine Cassiterite Flotation with Combined Reagents
    LUO Hong-Ying, Zhang-Ying, Chen-Rong, CAI Jiao-Zhong
    2019, 48(03):  30-34. 
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    The reagent is the key for the recovery of fine cassiterite by flotation. A large number of research and production practices have shown that the combination of reagents can promote the comprehensive recovery of cassiterite. In order to systematically and comprehensively understand the research and application of reagent of fine cassiterite， the use status of combined collectors， combined regulators， collectors and regulator for fine cassiterite flotation are reviewed， The advantages， mechanism and application status of combined reagents are introduced， and it is pointed out that achieving a better production target by using combined reagent is inseparable to the synergy between the reagents.
    Application Status and Existing Problems of 3D Laser Scanning Technique in Mine Surveying in China
    LIAN Xu-Gang, CAI Yin-Fei, HU Hai-Feng
    2019, 48(03):  35-40. 
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    As a kind of non-contact measurement technology，3D laser scanning technique has been widely used in mine surveying in recent years in China，involving slope monitoring in mining area，reserves management of open-pit mine，surface subsidence monitoring and other aspects of mine monitoring and research.Based on the analysis of the newly study results in recent years，the application status of 3D laser scanning technique in mine surveying in China is discussed，and some related existing problems are summarized.The study results show that the 3D laser scanning equipment and supporting software used in mine surveying engineering application and scientific study are mainly imported from abroad，and domestic equipment and software are few；from the aspects of data collection，processing and application of results，there are mainly problems in 3D Laser scanning technique for mine surveying，such as poor quality of collected data，low accuracy of point cloud data matching，low precision of point cloud data filtering algorithm，and inconspicuous results in special monitoring fields.Based on the above discussion results，further analysis results indicated that main study directions in the field can be summarized as following:①high-precision air-ground integrated data acquistion scheme，such as the integration of InSAR，LiDAR or oblique photogrammetry and ground based 3D laser scanning technique；②development of point cloud processing software with independent intellectual property rights，including point cloud data intelligent matching algorithm，intelligent high-precision point cloud data filtering algorithm；③late-stage application of 3D laser point cloud data，including deformation monitoring theory and method of ground planar objects，real-time dynamic monitoring method based on the integration of big data technique，artificial intelligent technique and 3D laser scanning technique.On the whole，further promoting the application of 3D laser scanning technique in mine surveying in China，is help for greatly improving the spatial 3D data processing ability of relevant engineers and technicians and increasing working efficiency.
    Caving Mining Technology for High Stress Fractured Orebody in the Northern Mining Area of Xishimen Iron Mine
    SONG De-Lin, REN Feng-Yu, LIU De-Xiang, HAN Jing-Wen, SUN Ding-Ding
    2019, 48(03):  41-47. 
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    The new prospecting orebody in the northern area of Xishimen Iron Mine belongs to gently inclined，fractured and thick to medium thickness orebody with serious ground pressure，which is extremely difficult to mining.Pillarless sublevel caving mining method is adopted in the mine，problems such as poor operation of equipment，instability of stope structure and roadway failure seriously are existed during the mining process.In order to alleviate the mining problems caused by high stress and fragmentation，the mining technology is improved from the aspects of equipment selection，determination of stope structural parameters，roadway layout，mining sequence and support measures.On the premise of ensuring smooth operation of equipment，it is determined that the scraper should be increased from 1.5 m3 to 2 m3 and the roadway section size should be increased from 3 m×3 m to 3.2 m×3.1 m under the condition of weak and soft surrounding rock；the section height is 13 m and the route spacing is 12 m which are determined by considering the stability of roadway，orebody conditions，rock drilling capacity and the development of discharge body；based on the principle of adapting to the law of ground pressure activity，it is determined that the mining route is better laid out vertically and the mining sequence is better to withdraw from the boundary of the orebody to the upper wall；supporting requirements of the surrounding rock with large ground pressure and easy to fall in a short time after excavation are analyzed，and the supporting measures of advanced bolt and U-shaped steel arch are proposed；the minimum side hole angle is 50°，which is determined according to the flow parameters of bulk，and the caving step is adjusted to 1.6 m according to the outcropping position of waste rock at the ore outlet.The above parameters and support measures have been successfully applied in the mining process of high stress fractured orebody in the northern area of Xishimen Iron Mine，therefore，the applicability of mining such orebodies of sublevel caving mining method without bottom pillar is enhanced.
    Grading Prediction Model of Rockburst Based on Rough Set-Multidimensional Normal Cloud
    LIU Ran, YE Yi-Cheng, ZHANG Guang-Quan, YAO Nan, CHEN Hu, WANG Qi-Hu
    2019, 48(03):  48-55. 
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    Accurate and effective grading prediction of rockburst is of great significance to reduce rockburst disasters.Maximum tangential stress of surrounding rock σθ，uniaxial compressive strength of rock σc，uniaxial tensile strength of rock σt and elastic deformation energy index of rock Wet are selected as the evaluation indexes of rockburst.Multidimensional normal cloud model is used as the prediction method of rockburst grade.Rough set is used to determine the weight of evaluation indexes.15 sets of rockburst examples at home and abroad are used as model construction samples，and the grading prediction model of rockburst based on rough set-multidimensional normal cloud is established.Firstly，fuzzy clustering analysis is carried on the evaluation samples，the evaluation indexes are filtered through the rough set，and the weight of evaluation indexes is determined.The determination degree of evaluation indexes is calculated according to the multidimensional normal forward cloud generator.Then，the comprehensive determination degree of evaluation samples is calculated by using the weight of evaluation indexes and the determination degree of evaluation indexes.According to the principle of maximum membership degree，the rockburst grade of evaluation samples is determined.The rockburst samples of Xinhua Mining Company are used to validate the grading prediction model of rockburst based on rough set-multidimensional normal cloud.The calculated results are consistent with the actual situation，which further indicates that the grading prediction model of rockburst based on rough set-multidimensional normal cloud has great practicality.
    Surface Stability Analysis of “Three Under” Mining Within Subsidence Basin in a Gold Mine
    CHENG Li-Nian, LI Xiao-Gang, YE Zhen-Hua, SUN Xiu-Zhu
    2019, 48(03):  56-61. 
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    In order to ensure the safety of surface villages，rivers and roads within subsidence basin and to maximize the exploitation of underground resources，and combing with the tailings cemented filling mining method under the structural condition of a large fault zone in a gold mine as a case，the safe mining depth of the mine is calculated as 108 m by using the theory of probability integral method，which is less than the thickness （130 m） of overburden rock and can meet the requirement of safety.The surface subsidence of a typical section within the movement range of "three-under" mining in a gold mine is studied and analyzed by FLAC3D numerical simulation method. Based on the calculation results it is show that the maximum inclined deformation is 0.022 mm/m and the maximum horizontal deformation is 0.019 mm/m.The deformation valus are close to the measured data，which meets the requirements of protection grade for buildings and structures. According to the characteristics of underground blasting engineering， the maximum allowable distance of blasting is calculated as 96 m，and the blasting vibration will not affect the surface. After the comprehensive analysis，it is concluded that the surface structures within the subsidence basin in the gold mine are safe and stable，which can provide reliable reference for the safety and efficiency production of the mine and the surface stability analysis of mining movement zone of similar mines.
    Study on Characteristics of Post-peak Stress-strain Curve and Acoustic Emission Parameters of Backfill under Uniaxial Compression
    LIU Yan-Zhang, LI Kai-Bing, LI Wei, GUO Bin-Lin, CHENG Ai-Ping, CAO Hua-Bin
    2019, 48(03):  63-67. 
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    Low-strength cemented tailings backfill （CTB） may be in the post-peak failure stage when controls ground pressure in backfill mining.The post-peak stress-strain curve characteristics and the acoustic emission（AE） parameters of CTB are closely related to the control of ground pressure.Therefore，uniaxial compression experiments and AE tests of CTB from unclassified tailings of Chengchao Iron Mine with cement-tailing ratio of 1:6 are conducted to obtain the stress-strain curve and the AE parameters.The post-peak stress-strain curve characteristics and failure process of CTB are analyzed based on AE energy rate and AE event.The result shows that the slope value of the post-peak stress-strain curve of CTB is negative，which decreases firstly，then increases and keeps a constant finally.The post-peak stress-strain curve could be divided into stage AB，stage BC and stage after C according to its slope variation.During stage AB，the stress-strain curve gradually becomes steeper and its slope value decreases with a convex sharp.The macroscopic cracks on the surface of the filling body increase gradually and the strength deterioration accelerates.The energy rate decreases dramatically，then increases rapidly and AE event location point concentrate partly.When the CTB enters the BC stage，the stress-strain curve becomes slow and its slope increase with a concave sharp.The macroscopic shear plain appears because of the expansion and convergence of shear cracks and the failure process becomes slower. The energy rate is high and decreases with AE event location points gathering into a strip.At the stage after C，the slope of the stress-strain curve keeps a constant.The shear plain slips and external load is supported by residual structure of CTB.Meanwhile，the energy rate and AE event reduce significantly.The post-peak AE parameters of CTB can well reflect its characteristics of stress-strain curve and the failure process.
    Elastic-plastic Solution of the Supporting Effect about the Anchorage Bearing Layer under Large Loosing Zone
    YU Tao, ZHAO Guang-Ming, MENG Xiang-Rui, DONG Chun-Liang, WANG Chao
    2019, 48(03):  68-72. 
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    For surrounding rock of roadway under large loosing zone， the interaction of anchor and surrounding rock forms “anchor bearing layer“ within the loose zone. In order to study the influence of “anchorage bearing layer“ on stress distribution of surrounding rock in roadway under large loosing zone， it is obtained that the support strength [pid] provided by “anchorage bearing layer“ in plastic zone under ultimate equilibrium state consists of two parts: bolt support strength [pi] and anchorage bearing structure strength， by theoretical deduction and practical analysis. According to the relationship between support strength [pi] and thickness of anchorage layer b， the concept of “anchorage limit thickness“ is proposed. For the surrounding rock outside the loosening zone， the stress distribution around the roadway can be recalculated and compared with the traditional Finner-Kastner solution. The practice shows that the bearing structure plays a dominant role in keeping the stability of roadway， and the coordination of support strength and bearing structure is more conducive to the maintenance of the roadway. Modified Finner-Kastner solution can provide some reference for understanding supporting mechanism of deep roadway，and also provide corresponding theoretical basis for supporting parameter design of roadway.
    Study on the Mesostructure of Compacted Area in Total Tailings Thickening
    HOU He-Zi, LI Cui-Ping, WANG Shao-Yong, YAN Bing-Heng
    2019, 48(03):  73-78. 
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    In order to carry out three-dimensional characterization and quantification of the meso-structure of compacted area in total tailings thickening，micro-CT is used to scan the compacted area.Based on volume rendering method，the three-dimensional reconstruction of flocs and pores structure is carried out，and the variation law of parameters such as fractal dimension of flocs， floc area ratio，pore branching distribution，pore size and pore connectivity density are studied.The results indicated that:①volume of the flocs in the compacted area accounts for a large proportion，and the floc connectivity is very good，the floc area ratio is contrary to the change trend of fractal dimension of flocs；②the majority of the pores have no more than two branches，and length of the branches is mostly short；③there are many pore structures in the compacted area，but the pore size is relatively small，the volume of pores less than 500 μm3 accounts for 98.6%，and the surface area of pores less than 500 μm2 accounts for 97.6%，the connectivity of pore structure is not good，and the highest connectivity density is 0.000 218. Through three-dimensional reconstruction of the floc and pore structure in the compacted area，as well as the analysis of the structural parameters of the pores and flocs，it is helpful to reveal the law of the mesostructure of compacted area in total tailings thickening.
    Study on Pellet Preheating and Direct Coal Reduction of High Grade Magnetite Concentrate
    ZHU De-Qing, YAN Xin-Cheng, PAN Jian, GUO Zheng-Qi
    2019, 48(03):  79-85. 
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    In order to understand the preheating and coal-based direct reduction characteristics of high-grade iron concentrate pellets， the preheating and direct reduction process conditions of pellets with organic additives were studied using a high-grade magnetite concentrate as raw material， and the performance of DRI pellets under the determined conditions was characterized. The results show that:①The compressive strength of preheated pellets increases with the prolongation of preheating time and the increase of preheating temperature. To obtain preheated pellets with compressive strength of 1 000 N/P， it takes 14 min to preheat at 1 100 ℃.②DRI pellets with iron grade of 94.12% and metallization rate of 98.64% can be obtained by reduction of preheated pellets with compressive strength of 1 000 N/P at 1 100 ℃ for 14 min， mass ratio of C to Fe of 1.5， temperature of 1 100 ℃ and time of 120 min.③DRI pellets only show the diffraction peaks of ferrous metal， the central metal iron is closely interconnected， the metal bond bridges are well developed， the iron grains are coarse， and the edges of the pellets are more obvious. The extremely low content of harmful elements in DRI pellets is a high quality raw material for smelting special steel， preparing powder metallurgical iron powder and high purity iron.④The sufficient compressive strength of preheated pellets is not only an important guarantee for the safe operation of rotary kiln， but also has a significant impact on the direct reduction rate. It is suitable to preheat pellets with compressive strength of about 1 000 N/P at 1 100 ℃ for 14 min.
    Study of Direct Reduction and Low Intensity Magnetic Separation on Siderite
    HE Wei, ZENG Wei-Wei, CHEN Xiang, LIAO De-Hua
    2019, 48(03):  86-89. 
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    Using a siderite ore as raw material， experimental study on direct reduction and low intensity magnetic separation process was carried out. The effects of roasting temperature， reduction time and carbon-iron mass ratio on the metallization rate of reduction roasted products were studied. And the effects of grinding fineness and magnetic field intensity on the indexes of low intensity magnetic separation were studied. The results show that the reduced product assaying 90.88% metallization rate was obtained under the conditions of reduction roasting temperature at 1 050 ℃ for 100 min and mass ratio of carbon-iron in 2.3. And the magnetic concentrate， assaying 92.40% iron and 96.60% iron recovery， were produced under the conditions of grinding size -0.037 mm account for 79.60%， magnetic field intensity of 79.62 kA/m. The magnetic concentrate can be used as raw material for steelmaking.
    Experiment on Reduction and Extraction of Nickel from High-magnesium Low-iron Nickel Laterite by Rotary Hearth Furnace
    WANG Jing-Jing, CAO Zhi-Cheng, GAO Jian-Yong, YAN Kun
    2019, 48(03):  90-94. 
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    The low-iron， low-nickel and high-magnesium nickel laterite ore was investigated， in which contains 17.68% iron， 1.62 nickel and 19.06% MgO， respectively. Nickel mainly replaces iron and magnesium and exists in the form of isomorphism in iron oxides and silicate minerals， accounting for 39.65% and 54.72%. To determine the high-efficiency development utilization process， small-scale basic tests were conducted to obtain the parameters of the reduction-roasting and grinding-separation process and pilot-scale test was carried out on a rotary hearth furnace with a pitch diameter of 8 m. The results showed that the sample was treated by coal-based direct reduction， water quenching and two-stage grinding and low-intensity magnetic separation. The mass ratio of laterite nickel ore， limestone and TN was 100∶10∶3， mole ratio of C to O was 1.2 (anthracite) ， the reduction time was lasted 40 min in the temporary of 1 280 ℃. The water-quenched calciation products at first stage grinding fineness of -0.074 mm accounting for 83.31%， and the magnetic field intensity of first stage low-intensity magnetic separation was 190.98 kA/m， second stage grinding fineness of -0.074 mm accounting for 97.43%， and the magnetic field intensity of second stage low-intensity magnetic separation was 127.32 kA/m. Under the optimal conditions， ferronickel powder product which contains 5.63% nickel and 60.39% iron with recovery of 80.83% and 75.14% can be obtained. The pilot product of the rotary hearth furnace was ground and separated. The obtained ferronickel powder product contains 5.26% nickel and 59.20% iron， while the recovery of nickel and iron were 80.84% and 74.98%， respectively. The research results can be used as the basis for engineering， and can also provide a technical reference for the efficient development and utilization of the same type of laterite nickel ore resources.
    Research on Improving the Recovery of Once Alloy in Nickel Matte
    ZHU Chuan-Qi, KOU Jue, SUN Fa-Zhao, HUANG Wen-Hao, MA Shu-Xian, SUN Chun-Bao
    2019, 48(03):  95-99. 
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    Due to the unreasonable once alloy recovery process and the working condition of the equipment in nickel matter grinding-flotation plant， the recovery of once alloy is not ideal， which not only seriously affects the recovery of the followed precious metals， but also adversely affects the subsequent smelting process. Therefore， the study on once alloy recovery was conducted on the mineral process mineralogy research of second stage returning sands from once alloy enrichment， to find out the reasonable process reform project. he mineralogy research shows that the main minerals in the second-stage classifier sand are nickel matte， Cu-Fe-Ni alloy and porphyrite； the particle size of nickel matte and porphyrite is mainly 27~150 μm， and the particle size of Cu-Fe-Ni alloy is coarse， 70% or more is larger than 75 μm； the coarse-grained Cu-Fe-Ni alloy have high degree of liberation，and the fine-grained alloy is mainly associated with nickel matte and porphyrite. Laboratory test shows that the coarse alloy screening—re-grinding on the undersize（-75 μm account for 70%）—low intensity magnetic separation is the reasonable process. The total recovery rate of precious metals has increased significantly to over 95%. Optimize the process according to the laboratory test result， the S content of the alloy is 8.94%， the recovery of Pt， Pd， Au are 99.38%， 94.07% and 96.12%， which is significantly better than the production index before the optimization. Therefore， this process is the reasonable process for the recovery of the alloy， and the lower S content creates favorable conditions for subsequent smelting.
    Crystallization Properties Research of High Alumina Bauxite at Low Calcination Temperature
    WANG Ying, NI Wen, ZHANG Yu-Ying
    2019, 48(03):  100-104. 
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    In order to find the activation mechanism of high alumina bauxite calcination at low temperature， the crystallization characteristics of bauxite calcined at different temperatures were studied and the effects of calcination temperature on the activity of the corundum crystals were investigated by combining the product type， crystal state and surface morphology. X-ray diffraction（XRD） was used to detect the type and crystal state of the calcined high alumina bauxite. The morphology of the calcined product was observed by scanning electron microscopy（SEM）. The results show that the high alumina bauxite calcined at 500 ℃ has the fasted dehydration speed， lowest crystallinity and the highest gelation activity， and is more suitable as a cementitious material admixture in the manufacture of alumina cement and grouting materials. During the calcination and heating process， the layered structure of diaspore is gradually bonded to form the granular structure of corundum， and the horizontal stripes on the surface of the particles are gradually clear， indicating that the crystallinity of the crystal is gradually increased and the reactivity is gradually reduced.
    Promotion of Na2CO3 on Sodium Oxidation of Low Valence Vanadium during Roasting of Siliceous Shale
    YANG Xin-Long, FENG Ya-Li, LI Hao-Ran
    2019, 48(03):  105-110. 
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    The addition of Na2CO3 in the process of sodium roasting of vanadium-bearing siliceous shale can promote the oxidation and leaching of vanadium. The promotion effect of Na2CO3 was investigated based on promotion effect by chemical composition analysis， XRD and SEM-EDS of roasting products and leaching residue from oxidation roasting with composite additive. The results showed that:① When the mass ratio of NaCl+Na2CO3 （3∶2 of mass ratio） to the raw material was 10%， the roasting temperature was 800 ℃， the roasting time was 180 min， the liquid-solid ratio was 10 mL/g， the leaching temperature was 80 ℃ and the leaching time was 120 min（stirring speed is 600 r/min）， the optimal leaching rate of vanadium was 84.96%.② During roasting， because of the destruction of Al-O octahedral lattice， the muscovite and illite in the raw materials were transformed into the melt particles containing Na， K， Al， Si and O. The addition of Na2CO3 increases the basicity of raw materials， enhances the reactivity of quartz and produces porous particles by co-melting with molten particles. ③With the addition of Na2CO3， the micropore structure produced by co-melting of melt particles and quartz and the gas channel formed by feldspar filling in the melt particles during roasting， enhanced the diffusivity of O2， increased the contact probability with low-valent vanadium in ore， and accelerated the process of vanadium oxidation， and increased the oxidation roasted effect of vanadium.
    Adsorption and Desorption of Gallium， Vanadium and Aluminum in Aluminum Mother Liquor of Guangxi by Amidoxime Chelating Resin
    ZHENG Qi, WEI Yue-Zhou, HE Chun-Lin, WU Jing, DAI Wei
    2019, 48(03):  111-115. 
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    In order to provide basis for separation and recovery of gallium in bauxite leaching mother liquor， the principles of adsorption by amidoxime chelating resin toward Ga， V and Al， and desorption by hydrochloric acid were studied. Results are as follows: ① amidoxime chelating resin has high selectivity for gallium， and the adsorption rate of aluminum was very low； the temperature had little effect on the adsorption of gallium and aluminum， and had great effect on the adsorption of vanadium. Adsorption rate of vanadium increased with temperature. Adsorption rate of gallium was faster than that of vanadium. Gallium adsorption is in accordance with quasi-second-order kinetics and particle internal diffusion model. The optimum adsorption conditions of gallium is: the adsorption temperature 25 ℃， the adsorption time for 60 min. ② Under the condition of 25 ℃ and low concentration hydrochloric acid， the desorption rate of gallium and aluminum adsorbed by amidoxime chelating resin is high， the desorption speed is fast， and the desorption rate is less affected by the desorption temperature， and the vanadium is difficult to adsorb. When the concentration of hydrochloric acid and temperature increased， the desorption rate of vanadium showed an increasing trend. The optimum desorption conditions of gallium is: hydrochloric acid concentration 1.0 mol/L， the desorption temperature is 25 ℃， and the desorption time is 5 min. ③ Due to the adsorption rate of gallium and vanadium in bauxite leaching mother liquor by amidoxime chelating resin is higher， and the desorption of vanadium is difficult， which affects the regeneration and recycling of resin. In order to separate and recover gallium efficiently and cheaply， it is necessary to reduce the vanadium content of the solution by adding NaOH to form sediment as much as possible before the resin adsorbs gallium.
    Extraction of Au（Ⅲ） from Aqueous Solution of H2SO4-NaClO3 by Ionic Liquids [C16mim][NTf2]
    CHEN Yue, ZHANG Cheng-Long, DENG Ming-Qiang, MA 恩　Wang-Rui-Xue, WANG Jing-Wei
    2019, 48(03):  116-118. 
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    The extraction of Au（III） from aqueous solution with imidazolium-type ionic liquid， 1-hexadecyl-3-methylimidazolium bistrifluoromethanesulfonimide （［C16mim］［NTf2］）-n-pentanol was investigated. The effects of pH， extractant concentration （g/L）， volume ratio between ionic liquid phase and aqueous solution （mass-volume ratio of ［C16mim］［NTf2］ to n-pentanol on the extraction of Au（III） were analyzed. The results indicated that the extraction rate of Au（III） increases with the increase of the volume ratio between ionic liquid phase and aqueous solution and pH of aqueous solution， the extraction rate of Au（III） increases with the increase of extractant concentration when pH<1.6. ［C16mim］［NTf2］ has obvious selective extraction effect on Au（III）. The extraction rate of Au （III） can reach more than 90% under the condition of the concentration of Au（III） in aqueous solution is 0.05 g/L， volume ratio between ionic liquid phase and aqueous solution of 1∶3， leaching gold solution of pH=1.6～2.0， ［C16mim］［NTf2］ concentration of 5 g/L， extraction time of 2 min at room temperature， and the selectivity coefficient β of Au for Al， Cu， Fe， Zn is 466， 780， 1 118 and 1 404 respectively.
    Study on Process of Preparing Expandable Graphite from Flake Graphite in Mozambique
    ZHONG You-Lai, QIU Yang-率, ZHANG Ling-Yan, CHEN Li-Quan, YUAN Yun-Ru, HE Fu-Chao
    2019, 48(03):  119-124. 
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    In order to determine the process conditions and properties for preparing expandable graphite from a natural flake graphite from Mozambique， the preparation conditions were studied， and its properties and mechanism were studied. The results show that the volume to mass ratio of HAc and HClO4 to graphite of +0.5 mm and 0.5~0.3 mm is 1.3 mL/g and 5 mL/g， the mass ratio of KMnO4 to graphite is 0.13， the reaction temperature is 50 ℃， the reaction time is 60 min， the expansion volume of expandable graphite at 850 ℃ is 450 mL/g and 400 mL/g， respectively； the volume to mass ratio of HAc and HClO4 to graphite of 0.3~0.18 mm is 1.3 mL/g and 5 mL/g， the mass ratio of KMnO4 to graphite is 0.17， the reaction temperature is 50 ℃， the reaction time is 60 min， the expansion volume of expandable graphite at 850 ℃ is 320 mL/g； the expansion volume of flake graphite of different grain sizes is roughly affected by the change of conditions， relatively speaking， the coarser the particle size， the better the effect of the oxidation intercalation reaction， and the larger the expansion volume of the produced expandable graphite； after the oxidation intercalation reaction， the gaps between the flake graphite layers are embedded with ClO[-4] and Ac-， the obtained expandable graphite is expanded by high temperature， rapid gasification decomposition of ClO[-4] and Ac- in inter-layer voids， and the large amount of gas generated destroys the molecular force between the graphite layers， spread the graphite sheet， formed expanded graphite with large volume， good worm effect and rich pores.
    Geological Characteristics and Prospecting Potential of Dalong Tungsten and Molybdenum Polymetallic Deposit in Tibet
    WU Xiao-Lei, XU Qing-Hong, LIU Yao-Hui, CHI Zhan-Dong, QIN Peng, SUN Guang-Yuan
    2019, 48(03):  125-134. 
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    Dalong tungsten and molybdenum polymetallic deposit is located in Mozhugongka County in Tibet， which is distributed in the famous northeastern Gangdese metallogenic belt，and about 8.38 ten thousand ton tungsten trioxide，2.98 ten thousand ton molybdenum，5.03 ten thousand ton copper，lead and zinc resources are obtained in the mining area.Based on the latest prospecting results in the mining area，the regional geological background， geological characteristics of the mining area and deposit geological characteristics are discussed，besides that，the deposit genesis，metallogenic conditions and prospecting indicators are also analyzed in detail.The study results show that:①the mineralization bodies （orebodies） are mainly hosted in the shallow metamorphic rocks of the sandstone and slate in Pangna Formation of Upper Permian Series，Ⅱ#，Ⅲ-1#，Ⅲ-2# and Ⅳ-1# orebody belong to main orebodies，which presents thick veins，lenticular and thin veins ，and are controlled by NE trending Dalong fracture，the wall-rock alterations are well developed with alterative zones，and the mineralization is closely associated with skarnization；②Dalong deposit genesis is a large skarn-hydrothermal vein type tungsten molybdenum polymetallic deposit，metallogenic materials derive from magmatic fluids，and it is closely associated with collision type intermediate-acid magmatic activity，the metallogenic fluids have the evolution trend of that from high temperature，high salinity to low temperature and low salinity.Based on the above analysis results，the metallogenic conditions prospecting potential are analyzed from the aspects of strata，structure and magmatic rock，and the results indicatedthat the favorable prospecting indicators of the mining area are NE trending fault，siliconized and iron cap alteration section，the tectonic intersection area of linear and circular structure，simultaneous silicification and ironation alteration，Cu-Pb-Zn-W-Mo geochemical anomaly，low resistivity and high polarizability geophysical abnormality； the prospecting potential of deep and margin of 15# exploration line，north of Ⅰ#， Ⅱ# ore-bodies and south of IV-1# ore-body are huge， they are worth conducting further prospecting and exploration work in the areas.
    Geological Characteristics and Genesis of Lubuzhen Pb-Zn Polymetallic Deposit in Tibet
    HONG Tao, XIA Fei, ZHONG Fu-Jun, LIU Guo-Qi, WU De-Hai, ZHOU Tang-Bo
    2019, 48(03):  135-146. 
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    Luobuzhen Pb-Zn polymetallic deposit in western South Gandese metallogenic belt is located in Angren County in Tibet.Based on the analysis of the regional metallogenic geological background and the geological characteristics of deposits，combined with the latest exploration results of the mining area，analysis of the ore-controlling factors， geochemical characteristics of the ore-hosting rocks and deposit genesis are conducted.The study results show that:①the mineralization bodies are mainly hosted in contact position between Paleocene-Eocene of Linzizong Group Pana Formation of dacite and biotite plagioclase granite porphyry，monzonitic granite porphyry，the orebodies are obviously controlled by NWW fracture，and also controlled by strata and magmatic rock，the orebodies are distributed with elenticular and stratoid forms，and obvious zoning characteristics，the mineralization alteration is very strong，and silicide，chloritization，carbonate lithification and pyritization are the main alteration in mineralization types；②ore-bearing biotite plagioclase granite porphyry and dacite are formed in Eocene and it is the product under the same magmatic activity；③biotite plagioclase granite porphyry and biotite have similar geochemical characteristics，which indicated that they have the same initial magma origin， biotite plagioclase granite porphyry with the geochemical characteristics of Ⅰ type granite，the petrogenetic type biotite plagioclase granite porphyry is the same as the ore-hosting rock of porphyry copper deposit in China；④Luobuzhen Pb-Zn polymetallic deposit belongs to the magmatic hydrothermal with mantle-derived properties，the ore-forming materials have multi-source characteristics and its metallogenic age is less than 51 Ma.Based on the above discussion results，the relative prospecting prediction study is done.The results show that the potential area B，where the Ⅱ# and Ⅲ# mineralized belts are located has good metallogenic prospect in north of Luobugangmu area，it is worth conducting further prospecting and exploration work in the area.
    Soil Geochemical Characteristics and Prospecting Potential of Au-polymetallic Deposit in Bangzhuoma Area，South Tibet
    YUAN He, XU Yun-Peng, SHAO Hua, HUANG Hao, WANG Lei, LUO Xian-Rong
    2019, 48(03):  147-155. 
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    Bangzhuoma area in Southern Tibet is located in the east-central part of Tethys Himalayas and situated in the Jiangzi-Longzi gold-antimony polymetallic metallogenic belt in Southern Tibet.Bangzhuoma area in Southern Tibet has great metallogenic potential and it is a favorable area for the exploration of gold-antimony polymetallic deposits.In order to achieve prospecting breakthrough in the area，some relative geological prospecting work is conducted，based on 1∶10 000 soil geochemical measurement data of the area，the integration method of element variation coefficient，variation coefficient interpretation diagram of Cv1 and Cv1 /Cv2，and fractal theory is adopted to analyze the nine elements of Au，Pb，W，Sb，Cu，Zn，Mo，Ba and Sn，the spatial enrichment distribution regularity and metallogenic potential of them are revealed.Based on the above discussion results，metallogenic prediction work is done based on metallogenic geological condition and element anomaly characteristics.The study results show that:①metallogenic potential of Cu，Zn，Mo，Ba and Sn is less than that of Au，Pb，W and Sb，and the abnormal lower limit values of the elements are obtained with value of Au 7.24×10-9，value of Pb 53.83×10-6，value of W 6.12×10-6，value of Sb 4.14×10-6；②according to element correlation relationship，three prospecting target areas in the Bangzhuoma area are delineated，Au is the main mineral in 1# prospecting target area，and its abnormal strength is 36.4×10-9，abnormal strength of Au in 2# and 3# prospecting target area are 49.8×10-9 and 47.3×10-9；③through trench engineering verification of 1# prospecting target area，a gold-bearing quartz vein with length of 150 m and thickness of 0.30 m is found，with Au grade of （3.64~4.78）×10-6；Au abnormal strength in 2# and 3# prospecting target area are both higher than that of 1# prospecting target area，which further show that prospecting potential in Bangzhuoma area is good.
    Kinematics Simulation Analysis and Parameter Matching Research of Combined Vibrating Screen
    XU Li, ZHANG Jie, GUO Nian-Qin
    2019, 48(03):  156-160. 
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    In order to study the vibration characteristics and the matching of motion parameters of the combined shaker， a three-dimensional model of the combined shaker was established by Solidworks， and kinematics simulation analysis was carried out by ADAMS. Through the virtual design and simulation of GDZS2460/2 upper and lower unit combined vibrating screen， it is obtained that the amplitude of the upper unit vibrating screen is 4.67 mm， the working frequency is 16.18 Hz， the inclination angle of the screen surface is 23°， and the amplitude of the lower unit screen is 9.16 mm， the working frequency is 12.16 Hz， and the inclination angle of the screen surface is 20°. Reasonable matching of the parameters of upper and lower unit sieves can make the material moving and layering faster in the upper unit and loosening and penetrating in the lower unit， so as to improve the processing capacity and screening efficiency of the combined vibration sieves， better meet different production needs， solve the problem of difficult screening of wet fine particles， and improve the service life.
    Factor Space-Unascertained Measure Model Based on Attribute Recognition of Tailings Dam Stability
    LI Hui, YI Fu, ZHANG Jia, DU Chang-Bo
    2019, 48(03):  161-167. 
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    There are many factors influencing the stability of tailings dam，which are coupled with each other and have a lot of unascertained information.In order to solve this problem，the stability of tailings dam is considered as the result factor，and 9 qualitative factors and 18 quantitative factors influencing the result factor are selected as condition factors to construct the factor space for attribute recognition of tailings dam stability.The unascertained mathematics theory is introduced into the factor space to construct the factor space-unascertained measure model， and the solution method of this model is discussed.The subjective and objective weights are calculated by analytic hierarchy process (AHP) and information entropy theory，and the synthetical weight of each condition factor is determined.By using factor synthesis method，the high dimension of factor space is reduced to one dimension combined factor axis，and the identification vector of combined factor is obtained.The stability of a tailings dam is evaluated according to the confidence criterion.This model is applied to the engineering practice to verify its feasibility and applicability.The results show that the attribute recognition results of tailings dam stability is basically consistent with the field discrimination results，which indicated thet the model established in this paper is help for solving the tailings dam stability evaluation problem and could provide valuable reference for diagnosis and evaluation of similar complex systems.
    Slope Deformation Prediction in Mining Area Based on IGM-LSSVM Model
    FENG Teng-Fei, LIU Xiao-Sheng, ZHONG Yu, MA Yu-Qing
    2019, 48(03):  168-172. 
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    Due to the poor monitoring environment，deformation monitoring sequence often accompanied with large fluctuations.The grey model （GM） is only suitable for solving exponential deformation series，and the least squares support vector machine （LSSVM） is difficult to effectively select the parameters in the deformation prediction.In order to sovle the existing problems of GM and LSSVM，an improved grey least squares support vector machines deformation prediction model （IGM-LSSVM） is proposed.Firstly，the geometric mean generating transformation is introduced into GM （1，1） model to enhance the exponential regularity of its input samples，and the deformation values are initially predicted，the residuals are also calculated；secondly，according to the disadvantages that artificial bee colony algorithm （ABC） is easily fall into local extremum when optimizing the parameters of LSSVM，the metropolis criterion is introduced and adaptive cooling function is designed to get an adaptive metropolis colony algorithm （AMABC）；finally，a set of residual values that predicted by LSSVM based on AMABC algorithm is used to compensate the GM （1，1） model，and the final prediction value is obtained.The deformation prediction results of a mining area show that the shortcomings that the ABC algorithm is easy to fall into local optimal solution is solved effectively，the average relative error of IGM-LSSVM，G（1，1） and ABC-GM-LSSVM are 1.223%，9.565％ and 3.200％，the prediction precise of IGM-LSSVM is higher than other two models，which further show that IGM-LSSVM is suitable for the the large fluctuation deformation monitoring sequence，and it has certain reference for realizing high precision deformation prediction of mine slope.
    Quality Evaluation of Farmland and Land Reclamation Suggestions of Mining Subsidence Area Based on Unmanned Aerial Vehicle Remote Sensing
    XU Yan, HU Zhen-Qi, CHEN Jing-Ping, CHEN Chao
    2019, 48(03):  173-181. 
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    In view of the problem of reduced yield and ecological damage caused by coal mining in the high phreatic mining area in the east of China，takes the maize crop of coal mining subsidence in Dongtan Coal Mine as an example，based on the multi-spectral image of the UAV （unmanned aerial vehicle） and the field measured data，and combing with the empirical model method，the inversion model of maize leaf area index of coal mining subsidence farmland is established and the quality evaluation of farmland carried out.The results show that the power function model established by the RRENDVI （red-red edge normalized difference vegetation index） is the optimal model with R2=0.756 and RMSE=1.125，and this model has features of high precision and reliability.Based on the model，LAI of maize from the study area was inverted to obtain the distribution map of maize LAI .According to the spatial distribution of maize LAI in the study area and the average value of local normal growing maize LAI，combing with the actual subsidence of water accumulation，the quality evaluation rules for subsided farmland are constructed，and the quality of coal mining subsidence is classified into five grades.According to the degree of damage of various grades of farmland，suggestions for reclamation are proposed，such as flattening，digging，deepening and padding.The above discussion results has important guiding significance for monitoring the damage to farmland in small subsidence area，evaluation the farmland quality and land reclamation.
    Particle and Fractal Characteristics of Reclaimed Soil under Different Land Utilization Methods in the Mining Area with High Phreatic Water Level
    FANG Li, YU Jian, FANG Feng-Man, ZHOU Guang, WANG Meng-Tian, JIE Jin-Fei
    2019, 48(03):  182-188. 
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    Taking the reclamined soil area （forest land， rice-wheat rotation and cotton-soybean rotation） in the coal mining subsidence areas with high phreatic water level in Liuxin Town in Xuzhou City as an example，and compared with uncloapsed land （forest land，rice-wheat rotation and cotton-soybean rotation） with the same utilization methods，the variation characteristics of aggregate stability，particle distribution，fractal dimension and soil bulk density，compactness and porosity of reclaimed soil by different utilization methods are analyzed，besides that，effects of different land utilization methods on soil reclamation are discussed.The study results show that:①for 0~20 cm thickness of soil layer，compared with the non-subsidence area with the same utilization methods，contents of clay and coarse clay of cultivated layer of reclaimed soil are decreased significantly，compared with the unused subsidence land，contents of clay and coarse clay of reclaimed soil are both increased，in particular，contens of clay and coarse clay in the surface layer of rice-wheat rotation area are higher than others；②different land utilization methods have different degrees of improvement on the aggregate structure and properties of reclaimed soil，it can be described that it the number of wet aggregate larger than 0.25 mm in diameter and wet aggregate mean mass diameter （WMWD） are both increased，the percentage of aggregate destruction （PAD） will be decreased and stability of soil aggregate will be enhanced，improvement effects of rice-wheat rotation method to the structure of soil aggregate is better than others；③there is a close relationship between particles distribution，fractural dimension of reclaimed soil，number of wet aggregate larger than 0.25 mm，WMWD，PAD and soil bulk density，compactness and porosity，and soil fractal dimension is effective for indicating the structure and stability of soil aggregates.The above discussion analysis results could provide reliable reference for taking reclaimed soil quality restoration measures in the coal mining subsidence area with high phreatic water level.
    Research on Process Optimization of Mining Acid Drainage Neutralization
    SHEN Qing-Feng
    2019, 48(03):  189-193. 
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    Lime neutralization is a common method for the treatment of mine acid drainage， whereas the performance of this process is often not so good as expected due to the problems of incomplete reaction of calcium oxide and poor settling property of sludge. In order to tackle these problems， the comparison study between direct neutralization by calcium oxide and sludge reflux + calcium oxide neutralization was performed on the wastewater from a copper mine. The results show that when the calcium oxide dosage was 24 g/L， calcium oxide slaking time was 20 minutes and stirring rate was 400 r/m， the pH value of sludge could reach over 6 after 75 minutes by direct neutralization. The pH value of wastewater can also reach over 6 when wastewater was neutralized with sludge(pH>6) with reflux ratio of 40% and calcium oxide dosage of 22.0 g/L， the concentration of metal ions was greatly reduced， meeting the requirements of tailing pond storage. The sludge reflux process could not only make good use of the unreacted calcium oxide to reduce the amount of new calcium oxide， but also improve the settling property and solid content of sludge， which are good for the clarification of the backwater of tailings pond.
    Study on the Lead and Zinc Removal from Pyrite Cinder by Chloride Roasting and Its Kinetics
    YAO Wei-Jie, ZHU De-Qing, PAN Jian, GUO Zheng-Qi, WANG Hao-1
    2019, 48(03):  194-199. 
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    Pyrite cinder is a large amount of solid industrial waste. The iron content is high， and high lead and zinc content often restrict its utilization as an important factor of iron resources. The process of chlorination roasting-magnetization roasting-magnetic separation can successfully remove lead and zinc and obtain high grade iron and low lead zinc content iron concentrate. The kinetics of chlorination roasting of pyrite cinder with CaCl2 as chlorinating agent was studied in order to reveal the limiting link of chlorination reaction of lead and zinc in the main phases in the process of chlorination roasting of pyrite cinder， the rate of chlorination reaction and the mechanism of chlorination roasting. The results showed that: ① The contents of iron， lead and zinc were 49.90%， 0.29% and 1.23% respectively. The majority of zinc was zinc oxide， and lead was mainly lead oxide， followed by lead sulfate and other forms of lead. When the mass ratio of CaCl2 to sulphuric acid residue was 6%， the chlorination time or roasting temperature is prolonged， and the chlorination volatilization rate of zinc and lead increased. When roasted at 1 000 ℃ for 5 min， the zinc and lead removal rates were 86.99% and 83.14% respectively， which created good conditions for subsequent magnetization roasting and magnetic separation to prepare high grade iron and low impurity iron concentrate. ② Comparatively speaking， it is easier to remove zinc by chlorination roasting than lead.③The apparent activation energy of zinc chlorination volatilization is 42.07×103 J/mol at 900~1 050 ℃， which is controlled by chemical reaction； the apparent activation energy of lead chlorination volatilization is 43.88×103 J/mol at 900~950 ℃， which is controlled by chemical reaction； and the apparent activation energy of lead chlorination volatilization is 20.34×103 J/mol at 1 000~1 050 ℃， which is controlled by diffusion. ④To enhance the removal of chlorination volatilization of lead and zinc can be achieved not only by increasing the temperature， but also by increasing the amount of solid chlorinating agent or by increasing the porosity and specific surface area of solid particles of pyrite cinder.
    Study on Mechano-chemistry Effect of a Low Activity Acid Slag Powder
    LI Mao-Hui, CHEN Zhi-Jie
    2019, 48(03):  200-204. 
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    In order to improve the resource utilization of slag powder， reduce the environment pollution of surface deposit and efficiently recycle the solid waste， the mechano-chemistry effect of low activity acid slag powder has been studied by means of microanalysis and strength test. The results show that the characteristic particle size of slag powder particle size after 30 min， 60 min and 90 min mechanical grinding decreased from 22.49 μm to 18.55 μm， 13.80 μm and 10.61 μm. The phase of slag powder does not change by mechanical grinding， but the surface morphology changes from massive particles with irregular polygons into small particles with pebbles and smooth surface. The compressive strength of filling body is increased with grinding time extension under the same conditions. After 60 min mechanical grinding， the compressive strength of test block meets filling requirements of the mine， so the potential activity of slag powder can be significantly improved by mechanical grinding， in turn the comprehensive strength of filling sample is increased.