Metal Mine

Progress of Intelligent Technology in Underground Metal Mines

LI Guoqing, WANG Hao HOU Jie, HU Nailian

2021, 50(11): 1-12.

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As the approach to mine production， intelligent mines have received wide spread attention in the mining industry on both domestic and international occasions.This paper compares and summarizes the objectives，concepts， practical experiences，key technologies and achievements of intelligent construction in metal underground mines both at home and abroad from two levels: macro-strategic guidance and mine construction practice.By analyzing the strategic orientation and industrial practices of intelligent mine in both sides，it is concluded that leading international mines follow the approach from mine automation to intelligence，while China's mines start from the intelligent strategy guided by the integrate IT application with industrialization and intelligent manufacturing，so that they go through the progressive process from digital mine to intelligent mine. The conclusion drawn from comparing the characteristics of intelligent mine construction at domestic and overseas shows that compared with mines abroad， China has advantages in technology accumulation， integration and innovation， speed of promotion， collaborative construction， and so on.Therefore，Supported by the rapid development of digital tecnique，5G technique and artificial intelligence，China's underground metal mines should develop the technical solutions and promotion methods that match its own resource conditions， technical level and personnel quality， by learning from the experience of foreign mines and giving full play to our own advantages. Finally， the trend of intelligent construction of underground metal mines in China is summarized， which should meet the requirements of green mines， combined with the extended application of deposit model， Intelligent-matched mining methods， and standardized data resources， to build more application scenarios facing 5G+ industrial Internet and virtual reality for production management and control， and to realize global optimization decisions with the help of big data.

Temporal and Spatial Characteristics of Microseismic Events During Roof Sliding Caving in Deep Metal Mine

LIU Jianpo WEI Dengcheng SHI Hongxu WANG Yongxin

2021, 50(11): 13-18.

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The inducing factors and occurrence mechanism of the roof sliding caving were studied by analyzing the temporal and spatial characteristics of microseismic events in Ashele Copper Mine. The results showed that the evolution of microseismic events directly reflects the changes of internal cracks in rock mass. Before the caving， the microseismic activity was obviously weakened， but the radiated energy was accelerated released according to a power law. In the monitored microseismic events， shear cracks play a dominant role， accounting for 68% of the total events， and are mainly concentrated in the ore-rock contact zone. To the contrary， the roof is the non-shear failure zone dominated by tensile fracture. The caving is caused by the combined action of the difference of physical and mechanical properties of rock mass on both sides of the contact zone and the strong blasting disturbance from nearby stope. When mining the boundary area of metal orebody， it is necessary to real-time monitor the rock mass stability and adopt measures such as timely filling and reducing blasting disturbance to weaken the risk of ground pressure disaster.

Simulation of Thickening Process for High Solids Concentration Tailings Using Coupled DEM-SPH Method

XIONG Youwei, LIU Fuchun, CHEN Wei LIU Enyan, LEI Xianquan,

2021, 50(11): 19-24.

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In order to realize the dynamic visual observation and quantitative characterization of the dense process of high-concentration tailings， and make up for the lack of applicability of conventional physical similarity simulation and numerical simulation methods，a method based on discrete element (DEM) and smooth particle fluid dynamics (SPH) coupled high-concentration tailings thickening simulation method is proposed， and based on this method，the unclassified tailings thickening process is simulated of a mine.Through the establishment of a full-scale deep cone thickener model consistent with the structure of the industrial machine， the simulation parameters of solid-liquid two-phase fluid are calibrated based on physical tests， and the underflow concentration of the thickener is used as the main evaluation index. The simulation results are compared with the on-site production situation. The results show that the error of the two is extremely small， which verifies the accuracy and reliability of the simulation model， and provides a new method for the research and optimization of mine filling dense technology.

Sandstone Creep in Different Water-bearing States under Graded Loading

LIU Honglei SONG Xu NIU Leilei LIU Xige

2021, 50(11): 25-32.

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In view of the problem that the creep damage of pillar under the effect of long-term in-situ stress is affected by its water content in the process of mining， creep tests of sandstone under step-loading under dry， immersed and saturated conditions were carried out. Based on ultrasonic tests， the ultrasonic characteristics of water-bearing rock during creep process are analyzed to explore the time effect of water on rock mechanical property degradation. The influence of water-bearing state on creep failure characteristics of sandstone is studied， and the precursor and time rule of creep failure of water-bearing pillar was revealed. The variations of ultrasonic wave velocity， dominant frequency and amplitude in the loading process were discussed， based on the ultrasonic test during creep processes of dry and saturated sandstones under multi-stage loads. The results showed that with the increase of stress level， the dominant frequency and amplitude of dry and saturated samples are reduced， resulting in a phenomenon termed with "frequency drift"， and the water-bearing sandstone shows a low-pass filtering characteristic. The damage of saturated sandstone is greater than that of dry rock. Influences of initial water-bearing state on creep deformation and its rate were obtained. The failure time arrives earlier and stress levels are lower， for the immersed and saturated groups. Before the specimens are destroyed， there is an inflection point where the creep strain increases slowly and then dramatically， and the specimens are destroyed within 0.5 hour after the creep strain beyond the inflection point. The creep failure modes of dry， immersed， and saturated sandstones are X-shape failure， entire fragmented blocks， and tensile failure along axis， respectively.

Study on the Joint Monitoring and Early Warning Technology of Instability and Failure in Roadway Rock Mass Based on Infrared and Acoustic Emission

YANG Zhengcang JI Liuyishu GUO Wei LIU Pei MA Song

2021, 50(11): 33-40.

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对岩巷工程灾害的预警预报和应急响应是减少人员伤亡和经济损失的重要途径，通过红外辐射和声发射联合监测含孔岩石在受力过程中的物理变化可以有效地模拟岩巷工程灾害演化与爆发。为此，开展了含孔洞岩石加载过程的红外辐射和声发射联合监测试验，对含孔洞岩石加载的红外辐射和声发射特征以及二者之间的关系进行了研究。结果表明：①极差曲线随应变的变化具有明显的阶段性特征，特别在最后阶段，极差曲线加速上升并出现突跳点，反映了温度场的分异现象和前兆特征，前兆时间平均为95.71%峰值应力；②声发射能率和声发射率曲线具有阶段性变化特征，在后期阶段普遍存在岩石破坏的前兆特征，前兆时间平均为82.68%峰值应力；③岩石加载后期，红外与声发射前兆具有递进性，即声发射前兆早于红外前兆，两者的时间分界线在92%~95%峰值应力；④红外和声发射变化特征的关系与岩石的损伤破裂演化以及两种监测技术的特点有密切关系。根据试验结果，提出了岩巷岩体失稳破坏的红外和声发射联合监测预警技术，讨论了两种技术的互补性，并给出了联合监测预警的技术流程，供相关研究和现场监测参考。

Delay Time Interval Optimization of Electronic Detonator Based on Spectrum Analysis and Linear Superposition of Seismic Wave

HE Li, XIE Xianqi, HAN Chuanwei ZHONG Dongwang WANG Honggang HUANG Xiaowu HUANG Binlin

2021, 50(11): 41-48.

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The delay time interval optimization of electronic detonator needs to consider the factors of the distance from the explosion center. Most of the existing research results are put forward for specific buildings， which need to solve the optimization problem of the delay time interval of the protected objects with different distance from the explosion center. Combined with a red sand rock excavation blasting project in China， the blasting vibration monitoring test of electronic detonator was designed and carried out， and the evolution law of peak particle velocity （PPV） and dominant frequency for seismic wave were analyzed. Based on the principle of linear superposition of seismic waves， the Fourier series fitting function of single hole blasting waveform was established by MATLAB program. The influence mechanism of number of superimposed waveforms and delay time interval （DTI） on the PPV of synthetic waveform （SW） was studied， and the optimization method of DTI for electronic detonator was proposed. The results show that， the PPV and predominant frequency of blasting seismic wave attenuate exponentially with proportional distance under the condition of red sandstone test site. The PPV of the SW tends to be stable when the number of superimposed waveforms reaches 23. The PPV of the SW is close to the PPV of the single hole blasting when the DTI is more than 2.6 times of the predominant period. The PPV of the SW may appear the minimum value or smaller value when the DTI is 0.4~0.6 times of the predominant period， but there will be interference superposition and vibration velocity enhancement when the DTI is about 1 times of the predominant period. The DTI optimization method can be used to calculate the optimal DTI between holes at any distance from explosion center.

Study on the Application of Emulsion Explosive Gas Inhibitor in Mine Blasting

ZHANG Xiliang, LI Erbao, YANG Haitao, YI Haibao, ZHAN Sibo,

2021, 50(11): 49-54.

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In order to reduce the concentration of toxic gas in blasting smoke， an inhibitor of toxic gas in emulsion explosive blasting was developed based on the chemical reaction of explosive explosion. Two factors affecting the effect of inhibitor addition ratio and loading mode were selected for experimental study. Four addition ratios of 0mass%， 3mass%， 5mass% and 8mass% were set， and four loading modes of uniform mixing， radial coupling with suction pipe， radial coupling without suction pipe and axial coupling were set.The test results show that : ① After explosive explosion， there are four main components of toxic gases. Among them， CO accounted for the highest proportion， accounting for about 37.36% ~ 37.98% of the total toxic gas. The production of NH3， NO and NO2 were similar， accounting for 21.22%~23.29%， 20.58%~20.8% and 17.99%~19.24% of the total， respectively. ② With the increase of inhibitor addition ratio， the detoxification rate increased first and then decreased， and 5mass% was the best addition ratio. ③ The anti-virus effects of different loading methods were in the order of uniform mixing structure， non-pipe radial coupling structure， pipe radial coupling structure and axial coupling structure. Among them， the detoxification rates of uniform mixed structure were 26.07%，56.79% and 59.54% higher than those of other structures respectively.

Experimental Study on Pre-splitting Blasting of Rectangular Shaped Charge in Complex Fractured Rock Mass

XU Shouxin HUANG Shaowei LI Erbao, YANG Haitao,

2021, 50(11): 55-63.

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It is of great significance to ensure the pre-splitting blasting effect in the jointed fracture zone in the mine side support operation.In order to solve the problems of poor pre-splitting blasting effect and low half-wall hole rate of complex broken rock mass， taking the west side of Xigou Limestone Mine of Jiuquan Iron and Steel Group Co.， Ltd. as an example ，combined with the characteristics of blasting holes and construction technology， a rectangular shaped charge device with an angle of 85° and an air interval of about 13 mm between the charge column and the hole wall was proposed， the directional rock breaking mechanism of the shaped charge jet was analyzed.ANSYS/LS-DYNA numerical model was established， and the stress of the monitoring points along the horizontal and vertical directions of the energy accumulation tank was extracted and analyzed.The analysis results show that due to the existence of the energy accumulation charge，the stress distribution of the rock mass around the blast hole was adjusted.Under the same distance with the hole wall， the stress along the horizontal direction of the center of the blast hole was significantly greater than that along the vertical direction of the center of the blast hole， and the former was 1.62~3.51 times that of the latter. The explosion energy fully acted on the direction of the energy accumulation tank， so that the energy along the vertical direction of the center of the blast hole， i. e.，the direction of the protected rock masswas weakened， and the effect of the energy accumulation seam was effectively improved.Further field test results show that the half-wall hole rate of pre-splitting blasting area with rectangular shaped charge is 64%~82%，and the unevenness is less than 20 cm，which is far better than that of ordinary pre-splitting blasting.The feasibility of rectangular shaped charge structure is verified，which has certain reference significance for similar mines.

Study on the Formation Technique of the Cutting Shaft by Natural Caving Method of Pulang Copper Mine

XIAO Weiguo LI Zhengrong CHEN Lin FENG Xinglong ZHU Junning LIU Huawu LI Qingsong

2021, 50(11): 64-68.

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Prerequisite of forming a drawbell is that to make a cutting shaft with long hole blast by one time on block caving mine.In order to get cutting shaft safely and successfully construction technology under the production process of DU411 to construct [?]762 mm empty hole and SimbaH1354 trolley construction [?]76 mm long hole in Pulang Copper Mine Based on the summary of the physical and mechanical properties of ore-bearing rock mass， the maximum tensile stress failure criterion and Mises criterion were adopted to carry out the theoretical calculation of the fracture zone and fissure zone formed by long hole blasting in four main ore-bearing rock masses.The results showed that the design of cutting holes should be arranged according to the scope of the fracture zone.The auxiliary and peripheral holes should be arranged according to fracture area.On this basis， the design parameters of long hole in cutting shaft were determined.According to the principle of compensating space requirement to achieve blasting effect，combined with the advantage of electronic detonator can determine the blasting time at will，the blasting time of each hole was calculated according to three stages such as rock breaking，flying to fill the compensation space， and axial moving out of the height range to form a new compensation space，on the basis，a method of determining t3 by the motion of free falling body driven by the aftershock was proposed，the effect of continuously creating compensation space with blasting was achieved.Through field tests，a cutting well with a height of 18 m and a section of 4 m×4 m was formed by a single medium-deep hole blasting.By using the technical scheme successfully tested， the mine has safely and high-quality completed the medium-deep hole blasting of 250 ore collecting slots， and no safety and quality accidents occurred in the process.

Development and Application of Prestressed Metal Microcrystalline Ceramic Composite Lining Plate

JIA Xiyong WANG Qingquan JIA Peixiang FU Miliang ZHANG Peng YANG Wei

2021, 50(11): 69-73.

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Microcrystalline ceramics is a kind of high performance materials with wear resistance， corrosion resistance and temperature resistance.They can be used in the environment with wear，corrosion and high temperature at the same time， and their performance is better than that of metal and organic materials.However， the significant deficiency of microcrystalline ceramics lies in the poor impact toughness， which is a brittle material. It is due to the formation of structural microcracks between grains caused by the sintering process of microcrystalline ceramics. When the microcrystalline ceramics are subjected to tensile and impact， it is easy to produce structural microcracks "instability" and fracture.Although advanced ceramic processing technology helps to improve the impact toughness of microcrystalline ceramics， its application is limited due to manufacturing cost.A prestressed metal microcrystalline ceramic composite was invented，which increased the impact strength of microcrystalline ceramics by 20~80 times.The research and development principle of prestressed metal microcrystalline ceramic composite lining plate was analyzed， and the mathematical model of prestress and the length of microcrystalline ceramic lining plate was established through experimental analysis， so as to provide a method to calculate the design parameters of the prestressed metal microcrystalline ceramic composite lining plate.This type of ling plate is applied to Xigou Coal Mine， Shaanxi Jianxin Coal chemical Co.， Ltd.， Mengda Mining Co.， Ltd.， Wushen Banner and other mining enterprises，the installation technical process of lining plate is described in detail， and the ideal results is achieved.The study results show that prestressed metal microcrystalline ceramics technology has a broad application prospect in mines， and can be further popularized and applied in the production of prestressed metal microcrystalline ceramics composite lining plate and pipe，which is helpful to solve the shortage of microcrystalline ceramics limited in application field due to poor impact toughness.

Research Progress on Mineral Flotation Kinetic Model and Influencing Factors

MA Qiang LI Yubiao LI Wanqing XIANG Yan LI Shihao

2021, 50(11): 74-80.

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Flotation kinetics has received increasing attention in recent years as it can provide a quantitative description of the flotation process and help to improve the automation of mineral processing. Based on the development of flotation kinetic models， this paper reviews the influence of mineral crystal structure， mineral particle size， mineral particle shape， chemical action and flotation equipment on mineral flotation kinetics. In addition， the development of flotation kinetics is also foreseen， and it is pointed out that the use of theoretical computational analysis and the combination of mineral process and pulp fluid motion laws can further enhance the guidance of flotation kinetic models to the actual flotation process.

Experimental Study on Comprehensive Recovery of Associated Elements in Pegmatite Lithium Polymetallic Ore in Xinjiang

WANG Tai, LI Peilun, LI Hanwen, ZOU Jianjian, WANG Wei YANG Kaizhi, WANG Chenhang,

2021, 50(11): 81-85.

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Tantalum， niobium and tin are associated with a pegemite type lithium polymetallic ore in Xinjiang， among which tantalum and niobium mainly exist in the form of tantalum and niobite， and tin mainly exist in the form of cassiterite. In order to improve the recovery rate of the associated elements， the principle process flow of coarse grinding， gravity separation preconcentration， high-intensity magnetic separation， and centrifugal separation was determined according to the properties of the ore， and the related condition test were conducted. The suitable particle size for gravity separation was determined as -0.35 mm by heavy liquid analysis. The pre-concentration of tantalum， niobium and tin was realized by screw chute roughing and shaking cleaning under this condition. High intensity magnetic separation of cassiterite and tantalum-niobite from pre-concentrated concentrate was carried out. The suitable working parameters were magnetic field intensity of 800 mT and pulsation frequency of 260 times/min. The non-magnetic products are mainly cassiterite and spodumene. Under the conditions of washing water of 2.0 L/min， ore feeding concentration of 30% and ore feeding amount of 1.0 kg/min， the suitable gravity acceleration of centrifugal separation is determined to be 50G in the centrifugal separating test. According to the technological conditions determined by the condition test， the whole process test of spiral chute roughing， shaking table cleaning， low intensity magnetic separation， high intensity magnetic separation and centrifugal gravity separation was carried out. Finally， tantalum and niobium concentrate with Ta2O5 grade of 13.90%， Nb2O5 grade of 29.14%， Ta2O5 recovery rate of 49.50%， Nb2O5 recovery rate of 58.37% and Sn concentrate with Sn grade of 41.45% and Sn recovery rate of 54.39% were obtained， which effectively realized the comprehensive recovery of associated valuable minerals.

Beneficiation and Metallurgical Process Study for a Gold-Silver Ore Contained Copper in Colombia

CHEN Shuibo, WANG Qiankun, SUN Zhongmei, XU Qihong, LI Liting, WU Weixin,

2021, 50(11): 86-90.

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The contents of value elements of a copper-containing gold-siliver ores in a Colombia are gold of 7.61 g/t， silver of 44.62 g/t and copper of 0.10%， respectively. The original process is the combined process of gravity separation and direct cyanide leaching for gravity separation tailings， causing the problems of low leaching rate of silver， a large amount of copper leaching and difficult in the subsequent treatment of pregnant solution. In view of the above problems， the combined process of beneficiation and metallurgy test research were conducted with gravity separation， copper prior flotation for gravity separation tailings， gold-silver flotation for copper flotation tailings and cyanide leaching of gold-silver concentrate. The results showed that: ① The sulfide minerals in the ores is mainly pyrite， and the gold-bearing minerals are mainly electrum. The silver-bearing minerals are mainly antimony tetrahedrite， and the copper minerals are mainly chalcopyrite. ② A comprehensive gold concentrate containing gold of 34.10 kg/t gold， silver of 9.34 kg/t， copper of 0.072%， gold recovery rate of 44.56%， silver recovery rate of 2.06% and copper recovery rate of 0.006 6% could be obtained by two-stage gravity separation process with Nelson gravity separation roughing and super-panner cleaning. ③ Copper prior flotation process is adopted for gravity separation tailings. Under the condition of grinding fineness of -74 μm accounting for 64%， Na2CO3 and Z-200 as regulator and collector respectively， copper concentrate with copper grade of 24.47%， gold grade of 402.4 g/t， silver grade of 8 841.6 g/t， copper recovery rate of 63.92%， gold recovery rate of 25.62%， silver recovery rate of 55.96% was obtained after two roughing and two cleaning process. ④ The total recovery of gold， silver and copper was 88.21% ， 77.02% and 63.92%， respectively， during the whole process test with combined process of beneficiation and metallurgy. Not only the copper minerals were recovered， the copper leaching amount and sodium cyanide unit consumption decrease， but also the subsequent treatment process of pregnant solution were improved. In the same time， the total recovery of silver was improved obviously， which greatly reduced the treatment amount of cyanide tailings.

Study on Fluidized Magnetic Roasting and Low Magnetic Separation Test of a High Magnetic Concentrate Containing Siderite in Anshan

ZHI Hui, DONG Zhenhai LIU Jianjun YANG Xiaofeng SUN Haoyan

2021, 50(11): 91-96.

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The contents of siderite in a high magnetic concentrate in Anshan is high， so it is difficult to achieve effective separation. Therefore， the fluidized roasting reactor was used to carry out the experimental study of low temperature pre-oxidation， ultra-low temperature reduction magnetization roasting and low magnetic separation on the basis of traditional reduction magnetization roasting. The results showed that: ① The TFe grade of the sample is 29.47%， the contents of the main gangue component SiO2 is 52.81%， and the contents of harmful impurities S and P are low. Iron mainly exists in the form of hematite with a distribution rate of 79.37%， followed by iron carbonate of 11.71% and magnetic iron of 3.46%. ② Under the conditions of 500 ℃ and 550 ℃， weakly magnetic wustite is formed in the process of direct reduction magnetization roasting with industrial producer gas as reducing gas. It is difficult to achieve complete magnetic transformation of iron mineral phase. ③ Stable and complete strong magnetic transformation could be obtained by low temperature pre-oxidation and ultra-low temperature reduction magnetization roasting. The appropriate parameters of fluidized magnetization roasting are pre-oxidation at 550 ℃ for 2.5 min and reduction roasting at 450 ℃ for 10 min. ④ Under the conditions of grinding fineness of -30 μm accounting for 92.60% and magnetic field intensity of 79.60 kA/m， a good index of iron concentrate with grade of more than 63% and recovery rate of more than 84% was obtained. ⑤ The results of XRD analysis， BSE mineral phase detection and EDS detection for the productions showed that there was no weakly magnetic hematite and wustite in the test process， the pre-oxidized ore maintained the initial shape of the phase boundary of the iron-bearing material in the original sample， and Mg and Ca elements in the siderite mineral phase through isomorphism did not migrate during the roasting process， also the process of grinding and low intensity magnetic separation couldn't achieve separation.

Effect of Dephosphorizing Agent and Roasting Temperature on Grinding Characteristics of Reduction Production for High-phosphorus Oolitic Hematite Ore

CHEN Zekun SUN Tichang WU Shichao LI Zongwei

2021, 50(11): 97-103.

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In order to explore the effects of the types and dosage of dephosphorization agents and roasting temperature on the grinding characteristics of the reduction products of high- phosphorus oolitic hematite from Algeria, the grindability of the reduction products and the distribution of iron and phosphorus after grinding were studied by means of screening analysis, chemical analysis and scanning electron microscopy. The results showed that: ① The particle size of the reduction products is mainly distributed in +0.074 mm and -0.030 mm, and the yield of -0.074+0.045 mm and -0.045+0.030 mm is small. ② The grindability of the reduction product increased with the increase of the dosage of dephosphorization agents. The effects degree of different dephosphorization agents on the grindability of reduction products were CaCO3+Na2CO3, CaCO3, CaCO3+CaF2, CaF2 and Na2CO3 in descending order. ③ Phosphorus in the production above 0.074 mm mainly exists in apatite and part of iron without dephosphorization agents. The distribution of phosphorus is more concentrated, mainly in the form of apatite with CaCO3 or mixed dephosphorization agents. The distribution of phosphorus is more uniform and exists in gangue as aggregate with iron when Na2CO3 is regarded as dephosphorization agent. The phosphorus is evenly distributed and exists in gangue and iron and the dephosphorization effect is poor with CaF2. ④ The yield of +0.074 mm grain increased, the other grain yield gradually decreased, and the grindability of the reduction product decreased rapidly with the increase of roasting temperature. The iron grade and phosphorus contents in +0.074 mm grain increased, and iron and phosphorus gradually enriched into coarse grain with the increase of roasting temperature.

Study on the Relationship Between Graphite Crystal Structure and Flotation Rate

WEI Shaowei ZHANG Lingyan, QIU Yangshuai, DING Dafa LIU Huailiang

2021, 50(11): 104-109.

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The study on the relationship between graphite crystal structure characteristics and flotation rate is of great significance. The contact angle test， crystal structure characteristics analysis and flotation rate test were carried out for graphite concentrates from Mozambique， Hubei Yichang， Jilin Wangqing and so on. The results showed that: ① Large flaky graphite and dense crystalline graphite generally have relatively large contact angles， while fine flaky graphite and aphanitic graphite generally have relatively small contact angles. ② The axial length a0 and c0 of graphite crystal in various graphite concentrates ranges from 0.246 51 to 0.248 27 nm and 0.671 29 to 0.675 68 nm respectively. The cell volume V ranges from 0.035 33 to 0.035 99 nm3， and the graphitization degree ranges from 68.78% to 94.57%. The large flaky graphite is with smaller cell volum， more complete crystal structure and higher graphitization degree. While the edge of the fine flaky graphite and aphanitic graphite crystal structure is connected with more oxygen-containing functional groups， and showed more crystal defects and lower graphitization degree. There is a negative correlation between content of 3R-polytypic and graphitization degree in graphite crystals. ③ The flotation rate of graphite concentrate accords with the classical first-order kinetic model. The graphitization degree is positively correlated with the flotation rate. The higher the graphitization degree is， the faster the flotation rate is and the higher the fixed carbon content of the concentrate is. Large flaky graphite generally has a higher degree of graphitization， and its flotation rate is faster than fine flaky graphite and aphanitic graphite， so its concentrate has a higher fixed carbon contents.

Study on Iron Particles Growth Characteristic in the Processing of Deep Reduction for a Vanadium-titanium Magnetite Concentrate

ZHANG Kai DING Yazhuo

2021, 50(11): 110-114.

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In the process of deep reduction， the particle size characteristics of iron particles have an important influence on subsequent sorting indexes. A vanadium-titanium magnetite concentrate in Panxi Area was regarded as object， and the influence of reduction temperature， reduction time and the amount of Na2CO3 mass ratio on the growth characteristics of iron particles were investigated through single factor condition test. The results showed that the amount of reduction iron in the samples increases， the metallization rate increases， and the size of iron particles increases with the increase of reduction temperature， reduction time and the mass ratio of Na2CO3. The reduction iron contents is 44.28% and the metallization rate is 86.84% with the reduction temperature of 1 000 ℃， the reduction time of 2 h and the mass ratio of Na2CO3 of 15%. The contents of particle over 19 μm is 53.29% and the contents of particle over 53 μm is 13.35% in the reduction condition. The recovery rate of metallic iron could reach more than 93% after further grinding and magnetic separation. Iron particles grow up through three stages of nucleation， growth and cooling in the process of deep reduction. In the end， more than 50% of iron particles formed by reduction form monomer， and a large amount of iron particles exist in the edge of mineral or the edge of internal pores， and a small amount of iron particles exist in the interior of mineral particles.

Test Study on Comprehensive Recovery of Iron and Lead from Cyanide Residue in Liaoning

ZHENG Jin, WANG Hongkai LI Binchuan, CHEN Jianshe, LIU Kuiren, HAN Qing,

2021, 50(11): 115-120.

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The cyanide residue from a gold smelting enterprise in Liaoning province contains the iron of 35.93% and the lead of 3.88%， which has certain comprehensive recycling value. An experimental study was carried out on the recovery of iron and lead for the residue by reduction roasting and fusion method. The influence of roasting temperature， roasting time， reducing agent dosage and additive dosage on the iron metallization rate and lead volatilization rate were investigated. The results showed that the metallization rate of iron and volatilization rate of lead reached 99.85% and 95.92% respectively with the roasting temperature of 1 250 ℃， roasting time of 60 min， coke powder dosage of 20% and CaO dosage of 25%. X-ray diffraction and scanning electron microscope analysis results showed that the additive calcium oxide can promote the reduction of iron， volatilization of lead and aggregation of metal iron particles in the roasting process， and has a certain effect of desulfurization. Iron ingots with the iron grade of 90.02%， sulfur contents of 0.016% and iron recovery rate of 88.92% were obtained by melting the roasting slag at 1 600 ℃ for 1 h. The toxicity leaching indexes of the roasting slag were far lower than the National standard. The purpose of harmless and resource utilization of cyanide residue was realized.

Oxidation Rates and Stoichiometry Characteristic of Pyrite in Coal Residue under Effect of Fe3+

JIN Tao, MENG Qingjun, FENG Yang, HU Zhengqi, CUI Yahong, FENG Qiyan,

2021, 50(11): 121-128.

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Coal residue with high pyrite contents could be oxidized in the presence of water and oxygen，and produce acid mine drainage （AMD）. Fe3+ is a stronger oxidant in this oxidation reaction. In order to study the oxidation characteristics of coal residue under the effect of Fe3+， the acid conditions with different Fe3+ initial concentrations were set up to simulate the oxidation of coal residue samples KL， DZ， SX from three coal measures with different sulfur contents and pyrite samples， and the ［SO42?］/［Fe2+］ stoichiometry in the acid production simulation test was used to verify the chemical reaction followed by the experimental system. The results showed that the oxidation rate of each sample increases with the increase of Fe3+ initial concentration in the liquid phase under acidic conditions. The experimental period of 1~7 days is the rapid oxidation reaction period of coal gangue and pyrite， and the acid production reaction is mainly controlled by chemical reaction. Under the experimental conditions， the oxidation rate of pyrite could reach 5.23×10-5 mol/(L·h)， the maximum oxidation rates of KL， DZ and SX were 1.91×10-5 mol/（L·h）、1.1×10-7 mol/（L·h） and 1.5×10-6 mol/（L·h）， respectively. It is found out that the oxidation process of coal residue is significantly different from that of pure pyrite. The oxidation rate of pyrite is higher than that of coal residue， but the iron dissolution rate of coal residue is higher than that of pyrite. The oxidation characteristics of different coal residue are quite different. DZ （22.89 kg/t， converted by H2SO4， the same later） with the lowest net acid production potential has lower oxidation rate than other coal residue， but KL （92.21 kg/t） and SX （90.58 kg/t） with the same net acid production potential have great differences in the oxidation process of Fe3+， which is showed in the ［SO42?］/［Fe2+］ stoichiometric ratio. KL has a similar ratio with pyrite， which follows the oxidation mechanism of FeS2 under the corresponding conditions ， but the ratio of SX is much higher than the theoretical value. This may be due to the composition of alkali producing minerals of coal residue. In general， the mineral contents and weathering degree of coal residue lead to the difference of acid production process. The higher the sulfur contents of coal gangue， the acid production pollution potential increases with the degree of weathering.

Ore Prospecting Prediction of Cu-polymetallic Deposit in Kaerqueka Area，Qimantage Area of Qinghai Province

WANG Panxi, ZHANG Peng WANG Zhenning, GUO Feng, FENG Naiqi, WANG Hongjie,

2021, 50(11): 129-141.

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Kaerqueka is located in the Qimantag area of western section of East Kunlun orogenic belt，and the westernmost of Indosinian gold，lead and zinc （copper，rare earth） tertiary metallogenic belt in Berkarik-Xiangride.The regional mineral resources are zonal distribution of NW—SE.Previous studies in this area focus on mineralogy，depositology and lithogeochemistry ，but lack of ore prospecting prediction research.Through the systematic summary of the geological，mineral resource，geophysical，geochemical and remote sensing characteristics in this area，the Cu-polymetallic ore prospecting prediction model is established，and the ore prospecting prediction is carried out.The study shows that:①The typical deposits in Kaerqueka area are Cu-polymetallic deposits，and the main metallogenic epoch is Indosinian.The ore-bearing layer is the Qimantag Group of Ordovician，the ore-bearing lithology is skarn and marble，and the contact zone is the most important ore-controlling structure，followed by faults.The intermediate-acid intrusive rocks in Indosinian are most closely related to regional mineralization.The ore minerals are chalcopyrite，sphalerite，galena，molybdenite，etc.②The sulfide oxidation zone is an important indicator for surface prospecting.Skarn polymetallic deposit can cause strong magnetic anomaly of positive and negative associated，high intensity，regular shape and good continuity.The local gravity anomaly is 0.2~1.0 mGal，the first-order anomaly superimposes the higher secondary anomaly when the density of the surrounding rock is high，it shows a large amplitude of spike-like anomaly while the surrounding rock is low density rock mass.The IP anomaly is often characterized by low resistance and high polarization.③Based on the known ore（mineralization） points，mineralization clues and important geophysical， geochemical anomalies and remote sensing anomalies，combined with ore-bearing formations，ore-bearing rocks and important ore-controlling structures，six prospecting prospects for polymetallic deposits are delineated，which can provide reference for conducting further exploration in the region.

Characteristics of Geological Structure and Its Ore-controlling Role in Shanzhou-Mianchi-Xin’an Bauxite Metallogenic Belt， Western Henan Province

LEI Xianquan, LIU Fuchun TANG Huadong XIONG Youwei LIU Enyan

2021, 50(11): 142-150.

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The Shanzhou-Mianchi-Xin'an bauxite metallogenic belt in Western Henan Province is an important resource base of bauxite in China. Through field investigation， structural analysis， statistical analysis and comprehensive research， the geological structure characteristics of the region and typical mining areas have been summarized， the formation mechanism and evolution process of regional tectonics have been expounded， the conceptual model of regional tectonic deformation dynamics has been established， the control effect of different scale structures on bauxite mineralization， preservation， spatial distribution and destruction has been analyzed， and the important significance of geological structure research on bauxite prospecting， exploration and mining has been pointed out. The research results show that:① The Mesozoic-Cenozoic tectonic deformation in this area is mainly manifested by faults， with the formation of faulted blocks and faulted depression as the main characteristics. These geological formations are the product of the near south-north asymmetric extrusion and left-lateral shear-tension coupling during the Indosinian-Middle Yenshanian epoch and the regional extension during the Late Yenshanian-Himalayan epoch. ② On the regional tectonics， there are three groups of faults with different properties， including near EW， NW and NE trending， as well as faulted blocks and depressions of different scales formed by their cross cutting， which play an important role in controlling the occurrence and spatial distribution of bauxite. The well-preserved deposits are mainly distributed in the northern margin of faulted basins.③ Normal faults are widely developed in all mining areas， which have significant damage to the integrity and continuity of ore beds， and have serious adverse effects on mineral exploration ， resource & reserve estimation and mining design & production. Therefore， it is necessary to pay more attention to and strengthen the structural ore-controlling research in this area，so as to better guide the bauxite prospecting， exploration and mining practice.

Study on the Flow Field Characteristics and Separation Performance of the Single and Double Overflow Pipe Hydrocyclone

LIU Guoqing ZHANG Yuekan LIU Peikun YANG Xinghua CHEN Bo

2021, 50(11): 151-157.

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The ordinary cyclone could only get the overflow of fine particles and the underflow of coarse particles in the once classification， difficult to achieve the requirements of fine classification of narrow particles. The double overflow pipe hydrocyclone was designed in order to obtain the fine particle size and narrow grain products in the once classification. The comparative study of the velocity field and pressure field in the cyclone， the granularity of field and separation performance of the single and double overflow pipe hydrocyclone were conducted by numerical simulation and experimental study. The numerical simulation results showed that the hydrocyclone with double overflow pipe structure could obtain three kinds of productions including internal overflow， external overflow and underflow after once separation. Compared with the single overflow pipe hydrocyclone， the tangential velocity and internal static pressure of the double overflow cyclone are higher， while the radial velocity， axial velocity and turbulent kinetic energy are smaller， indicating that the double overflow pipe structure can strengthen the separation process and improve the separation performance. The experimental results showed that compared with the single overflow pipe hydrocyclone， the underflow concentration of the double overflow pipe hydrocyclone decreases by 8.3 percentage points， and the yield of the underflow increases by 3.25 percentage points. The cumulative particle contents below 45 μm in the internal and external overflow product increases by 1.15 percentage points， and the comprehensive classification efficiency increases by 1.26 percentage points. The research results could provide a certain reference for the research and development of narrow-particle cyclone separation equipment and technology for multiple products.

The Influence of Straight Pipe Length of the Bottom Outlet on the Separation Performance of the Hydrocyclone

ZHANG Zhichen ZHANG Yuekan LIU Peikun YANG Meng YANG Guangkun

2021, 50(11): 158-164.

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The straight pipe length of the bottom outlet is the important section. In order to find out the influence law of the straight pipe length of the bottom outlet on the separation performance of the hydrocyclone， the influences of different insertion depths of the underflow straight section on the pressure field， velocity field and turbulent kinetic energy of the cyclone were studied by numerical simulation and experiment. The simulation results showed that with the increase of the absolute value of straight pipe inserted into the depth， the static pressure， tangential velocity and turbulent kinetic energy of flow field appears varying degrees of increase， which could effectively increase the centrifugal strength and strengthen the separation effect. While the radial velocity decrease with the increase of the absolute value of straight pipe inserted into the depth， and the decrease of the radial velocity was beneficial to the improvement of the accuracy of classification. The test results showed that with the feeding pressure of 0.1 MPa， the feeding concentration of 10% and the median particle size of 16.75 μm， the underflow concentration times increase from 4.61 times to 6.48 times and the median particle size of the underflow product increases from 49.32 μm to 65.88 μm with the straight pipe length of the underflow port increasing from 0 mm to 80 mm. The median particle size of the overflow product increased from 8.57 μm to 21.16 μm， the fineness of the overflow product became larger， the separation particle size increased， and the comprehensive classification efficiency was increased by 13.85 percentage points compared with the traditional hydrocyclone.

Safety Situation Analysis and Sensitive Factors Study of Tailings Pond

KE Lihua, HUANG Changchang, LI Quanming LI Zhentao YE Yicheng, ZHANG Guangquan, ZHANG Ying,

2021, 50(11): 165-172.

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Aiming at the requirements of daily safety management and control of tailings pond， using set pair analysis method and extension theory， a tailings pond safety situation and sensitive factor analysis model based on set pair extension side distance correlation algorithm is proposed.The concept of similarity， difference and opposition in set pair analysis and the description method of matter element in extension theory are used to establish the analysis system for describing the safety situation of tailings pond. Considering that the safety evaluation index of tailings pond has the characteristics of "extremely large" or "extremely small"， the set pair extension side distance correlation algorithm is established based on the principle of the optimal value of the end point of the safety level interval. The similar， different and opposite parameters of the safety state of tailings pond are calculated， and the comprehensive safety connection degree of tailings pond and the safety impact connection degree of the index are determined. Based on the definition of set pair situation， an analysis model of the safety situation of tailings pond and its sensitive factors was constructed. By calculating the set pair situation of tailings pond and analyzing the similar， different and opposite parameters， the change trend of the overall safety state of tailings pond has been reflected well and the influence degree of various evaluation indexes on the safety status of tailings pond has been systematically analyzed so as to provide a working path for formulating effective safety prevention and control measures.A tailings pond safety situation and its sensitive factor analysis model based on set pair extension side distance correlation algorithm is used to analyze the safety status and change trend of a tailings pond. The analysis results show that the overall safety state of the tailings pond is N2， and its set pair situation is 0.57， which reflects that the tailings pond is in a good condition， but its safety state has a strong trend of developing to the unsafe level. At the same time， the first level sensitive indexes affecting the safety state of the tailings pond are determined as the downstream slope ratio （C22）， bulk density （C32） and geological condition （C41）， and the control degree from large to small is C22，C32 and C41， which is basically consistent with the actual situation of the tailing pond.

Study on the Opportunity and Area of House On-site Reconstruction During Mining

AN Shikai ZHOU Dawei LI Liang XU Yanfei BAI Zhihui WANG Xiao

2021, 50(11): 173-180.

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At present， the mines in Eastern China are dominated by pressed coal in villages. Due to the shortage of land， mining enterprises are facing some problems， such as the difficulty of coal mining under the village， the long period of village reconstruction after surface stability， and seriously affecting the lives of villagers. Therefore，the idea of local reconstruction of village houses during mining is adopted，the time and area of local reconstruction of houses by the residual deformation of the surface is selected， and the mining space is divided into surface subsidence space， non releasing space， that is， the space occupied by rock fragmentation and expansion， and releasable space from the perspective of spatial transmission and distribution of coal mining. Besides that，the calculation method of residual deformation by combining the model of probability integral method and time function is deduced. Taking Fengfeng mining area as an example， the results show that the proposed calculation method can accurately calculate the time and area of in-situ reconstruction during mining. Compared with rebuilding houses after surface stabilization， the time of building houses during mining is advanced from 4.2 a to 0.5 a， which is 3.7 a earlier， and the time efficiency is improved by 88.1%. The time efficiency of house reconstruction during mining has been greatly improved， which has greatly improved the living environment and quality of local villagers. The research results are useful for the in-situ reconstruction of houses in coal mining under villages in mining areas in China.

Optimization of Slope Ecological Restoration Scheme of Open-pit Mine Based on Digital Identification Technology of Rock Mass Structure

LU Shidong ZHANG Dong TU Meiyi ZHOU Hongwen PAN Ruohan KE Bo

2021, 50(11): 181-187.

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Open-pit slope ecological restoration is an important part of green mine construction. At present， there are many influencing factors， poor scheme allocation and imperfect evaluation system in the selection of open-pit slope ecological restoration scheme. The research on the optimization of open pit slope ecological restoration scheme plays an important role in promoting the construction of green mines in China. Taking the open-pit slope of Tongshankou mine as the research object， the surface fine digital model of Tongshankou mine is constructed by using the method of three-dimensional reconstruction and theoretical analysis and high-precision three-dimensional laser scanning technology. The slope zoning is studied in combination with the engineering geology of the mine slope， and seven slope zoning maps are obtained. Based on the digital identification technology of rock mass structure， the slope angle， height and rock mass joint fracture density parameters of each zone are obtained. The rock mass quality of each zone is evaluated by rock mass BQ classification method. The results show that the rock mass quality grade of zone 5 and zone 7 is grade I， Zone 1， 2， 4 and 6 is grade II， and zone 3 is grade III. On this basis， the optimization of slope ecological restoration scheme is carried out around the rock mass quality classification of slope zoning. The research shows that thick base material spraying technology is recommended for zone 5 and zone 7 slopes， three-dimensional network vegetation technology is recommended for zone 1， 2， 4 and 6 slopes， and guest soil spraying technology is recommended for zone 3 slopes. The above analysis further shows that the method of realizing the scientific zoning of slope and the optimization of ecological restoration scheme in each area by using the digital identification technology of rock mass structure has a certain reference value for improving the efficiency and quality of slope ecological restoration in open-pit mines.

Analysis on the Problems and Key Points of the Compilation of Mine Land Reclamation Scheme of Sichuan Province

LI Tian XIE Chuan WANG Daguo YU Chen,

2021, 50(11): 188-196.

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The Mining Geo-environment Protection and Land Reclamation Scheme（short for the“scheme”） is the sole basis for the implementation of mine land reclamation and the supervision and inspection of the quality of land reclamation by relevant departments. In order to clarify the problems existing in the compilation of the scheme and the drawing of the attached maps， and standardize the key points in the compilation and drawing of the land reclamation of mines， on the basis of reading the relevant regulations and the latest national policy documents， and summarizing 250 provincial-run the schemes which had been reviewed and approved in Sichuan Province， the main problems existing in the compilation of mine land reclamation and the drawing of the attached maps are analyzed. Combined with the status of review of mining land reclamation in Sichuan Province， it is found that there are some problems in compiling the scheme， such as incorrect time limit of the scheme， insufficient demonstration of soil pollution in damaged areas， incomplete responsibility range for reclamation， incorrect reclamation direction， inadequate reclamation engineering measures， irregular drawing of attached maps， failure to clarify the relationship between attached maps and so on. In the light of these problems and the preconditions for the preparation and submission of the scheme，the essentials of compiling each chapter of mine land reclamation scheme in Sichuan Province are clarified，and the the main contents and production requirements for attached maps such as the general layout map， the remote sensing image， the land utilization situation map， the land destruction map and the land rehabilitation planning map are standardized，so as to provide a reference for the future evaluation and inspection of mine land reclamation.

Study on Vegetation Coverage in Daning Mining Area Based on Pixel Dichotomy

ZHONG Qi HU Jinshan KANG Jianrong

2021, 50(11): 197-203.

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n order to explore the change of vegetation cover in mountainous mining area， taking Daning mining area as an example， based on the 1998—2017 Landsat images， the fractional vegetation cover （FVC） in different periods of mining area was inversed by selecting the data of seven periods and substituting them into the pixel dichotomy model， At the same time， the change trend of vegetation coverage in the mining area is calculated by using Sen + Mann-Kendall trend analysis method. By studying the temporal and spatial variation characteristics and variation trend of vegetation coverage in different periods in Daning mining area， combined with underground mining activities， the temporal and spatial variation characteristics of vegetation coverage in 19 years in the study area were quantitatively analyzed， and reasonable suggestions were put forward according to the situation of the study area. The results show that: ① From 1998 to 2017， the overall vegetation coverage area of the study area increased by 4.724 1 km2， and the change trend is from gentle to good. The vegetation coverage area of the mining area accounts for 87.52%， which is mainly due to the implementation of relevant environmental protection and ecological construction policies and the impact of the environment of the mining area； ② Through the analysis of the response of surface vegetation to mining activities from 2005 to 2010， it is found that the vegetation coverage area after mining is smaller than that before mining， which indicates that mining activities will lead to the reduction of vegetation in the mining area and the destruction of ecological environment in the mining area； ③ Through the inversion of the vegetation coverage of the whole mining area and the working face of the mining area， it is found that the vegetation coverage of the study area is consistent with the mining activities in time and space.

Analysis on the Characteristics of Mining Subsidence Damage in Majiagou Mine of Tangshan City

MA Bingtai WANG Ying ZHOU Jinhua PANG Guoxing WANG Lejie

2021, 50(11): 204-210.

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It is essential to analyze the characteristics of mining subsidence for the interpretation of the mechanism of mining subsidence and ecological rehabilitation of mining areas.The occurrence characteristics of coal and bauxite resources in Majiagou mining area of Tangshan were analyzed based on the field surveying of mining-induced subsidence and its resulted damage.The results show that steeply inclined coal seam mining was caused the ground to form a step-like non-continuous deformation crack in the direction of the dip， the structure at the crack was damaged severely， located outside the cracks of the structure was damaged slightly， it shows that the mining subsidence occurs concentrated deformation at the crack.According to the prospecting survey， ground cracks formed during the original mining process were closed with the stability of the mining subsidence， but little cracks still exist. In the area of the outcrops of steeply inclined coal seam， not only the surface of the phenomenon of pumping collapse in the mining process， after several years of mining subsidence stabilization， it is still possible to pumping collapse.The findings and characteristics would be useful to guide the exploration of the mined-out area and the construction over the collapsed land in Majiagou abandoned mining areas.In addition，these findings can also be beneficial to give a reference for the study of mining subsidence and landscape ecological restoration of those mining areas with similar geo-mining conditions.

High-purity NH4VO3 Preparation with Short Process Using Vanadium-removal Slag

LIU Jingjing

2021, 50(11): 211-214.

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Vanadium-removal slags of crude TiCl4 contain vanadium of 2% to 5%, indicating high recycling value. In order to realize the low cost recovery of vanadium resources from vanadium-removal slag, a new process of direct roasting, ammonium salt leaching, precipitation of vanadium to prepare NH4VO3 from vanadium-removal slag was proposed. And the related conditions tests were carried out focusing on the effects of roasting temperature, NH4HCO3 dosage, leaching temperature and leaching time on vanadium extraction. The results showed that: ① After roasting at 650 ℃ for 150 min, the main phases of the roasting samples are rutile TiO2, anatase TiO2, Al2O3, V2O5 and SiO2, and the vanadium oxidation rate reaches 78.12%. The low- cost extraction of vanadium could be realized by ammonium salt leaching. ② The optimum leaching conditions of roasted samples were determined as follows: dosage of NH4HCO3 of n(NH4+)/n(V) =2, ratio of liquid to solid of 5 mL/g, leaching temperature of 80 ℃, leaching time of 30 min. Under the above conditions, the leaching rate of vanadium could reach 76.65%, and the concentration of vanadium of leaching solution is 5.71 g/L. After circulating leaching for four times, the concentration of vanadium increased to 19.66 g/L. The high concentration leaching solution could directly precipitates vanadium to obtain NH4VO3 product with purity above 99%, which meets the requirements of standard Grade I product (YS/T 1022—2015). XRD analysis further confirms that it has high purity. The research results can provide technical support for the short process recovery of vanadium resources from vanadium-removal slag.

Research on Mechanical， Impermeability and Hydration Characteristics of Iron Tailings Concrete

CHENG Heping LU Lu

2021, 50(11): 215-220.

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In order to explore the influence of iron tailing ore addition on the mechanical properties and durability of iron tailing concrete， the compressive strength， impact resistance， impermeability and hydration properties of concrete with different iron tailing addtions were investigated by taking iron tailing ore from Tangshan as aggregate. The results show that: ①With the increase of iron tailing sand content， the compressive strength and flexural strength of concrete both increase first and then decrease. The compressive strength is the highest when the iron tailing sand content is 10%， and the flexural strength is the highest when the iron tailing sand content is 20%. The impact energy and fracture absorption energy of concrete tend to increase first and then decrease. When the iron tailing sand content is 20%， the impact energy and fracture absorption energy reach the maximum value. ②As the content of iron tailings increases， the water absorption of concrete gradually decreases. The carbonation depth and penetration depth of concrete first decrease and then increase. When the iron tailing sand content is 20%， the carbonization resistance and impermeability of the concrete are the best. ③As the hydration reaction continues， the heat release rate of hydration shows a trend of increase， decrease， increase， decrease， and decrease. However， the hydration heat release rate of concrete under the same hydration time decreases with the increase of iron tailing sand content. With the extension of the hydration time， the heat release of concrete hydration shows an increasing trend. With the increase of iron tailings sand content， the lower the hydration heat of concrete under the same hydration time.

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