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    15 August 2014, Volume 43 Issue 08
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    Analysis on the Fragmentation Energy Consumption of Magnetite Quartzite under Impact Loads
    GUO Lian-Jun, YANG Yue-Hui, ZHANG Da-Ning, LI Lin
    2014, 43(08):  1-5. 
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    Impact tests are conducted on magnetite quartzite samples by using SHPB apparatus with different impacting velocities.Based on the test results,the law of energy dissipation and fragment-size distribution of rocky materials under impacting loads was analyzed,and then the relation models of the fragmentation energy consumption of magnetite quartzite were setup.The concepts of strain rate intensity index and energy-time density were suggested.The concepts reveal that the effective energy consumption is not only associated with the totally input energy,but also is closely related to the energy-time density.By analyzing the samples fragmentation and compared with sustains time and strength of reflect stress waves,the relationship models of dynamic strength of rock related to strain rate and energy-time density were established initially.From this,the notion of energy output structure was described quantitatively,and the bridge of explosives energy output to energy consumption of rock fragment was set up,and a new idea of energy coupling between rocks and explosives was proposed as well.
    Frequency Band Energy Distribution Characteristics of Blasting Vibration Signals
    SHI Chang-Yan, ZHAO Xing-Zhu, JIANG Hong-Bo, LI Yuan-Hui
    2014, 43(08):  6-10. 
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    Studying the propagation law of blasting seismic waves is very important for blasting vibration control.With Hongtoushan copper mine as the engineering background and setting measuring point of blasting vibration signal in the tunnel，blasting vibration signals in actual production were collected with vibration monitors.Based on wavelet analysis technology，and using MATLAB procedures，decomposition and reconstruction of the signal wavelet were made to select suitable wavelet for the gained signal.Then，energy distribution characteristics of millisecond blasting vibration signals were investigated.Effects of distance from blast center，total amount of explosives and propagation direction on the energy distribution law of blasting vibration signal were studied.The results showed that：With distance from blast center increasing，the low frequency portion of blasting vibration signal occupied larger percentage of total energy; When using multi-segmented millisecond blasting，the energy distributed evenly，although the total explosive increased; The energy distribution of blasting vibration signals in the back and lateral direction have some differences，and the propagation direction significantly impacts on the energy distribution of vibration signal.
    Numerical Analysis of Stoping Optimization of Large-scale Deep-buried Stopes with Hard Rocks
    ZHU Fang-Cai, LIU Bing-Xiao, YANG Cheng-Xiang
    2014, 43(08):  11-14. 
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    With large-scale exploration of underground resources，stability of large-scale deep-buried stopes with hard rocks attracts more and more attention.Combined with the feasibility study on mining，and based on the primary-stage basic geological exploration，the stress of original rock in mining area and its physical and mechanical properties are achieved.On this basis，FLAC software is adopted to make the numerical simulation on stability of mined-out area（group).5 typical indexes are chosen to consider the excavation of underground mined-out area，including maximum tensile stress，maximum compressive stress，plastic zone area，tensile failure area and displacement of key position.With the orthogonal experiment design，the effect of stope structural parameters on the stope stability under different evaluation index is analyzed to obtain the optimal stope structural parameters.Through comprehensive analysis，the stope structural parameters for design reference are achieved.
    New Type Chamber-free Tailings Cemented Filling Technique
    LIU Xiao-Jun, MA Yi-Min
    2014, 43(08):  15-18. 
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    In recent years,the underground cemented filling stoping method with tailing from dressing plant has been widely applied in large-medium underground iron mine.The tailing cemented filling system mainly consists of vertical chamber and two-stage activated agitator,which has characteristics of large site area,complex structure,and high investment and operation costs.Combined with the actual situation of mine,Liutangfang iron mine used tailings from its own dressing plant to carry out the thickening tests by hydrocyclone.A set of low concentration chamber-free tailing filling system is developed with the aid of the automatic intelligent control system.Its application in industry achieved good effect.The industrial application showed that the utilization rate of tailings reached more than 70%,and tailings concentration reached 65%~70%.Overflows from cyclone directly went into the tailings pond.The whole filling system adopts the remote centralized control.No manual operation is needed on site.Meanwhile,the intelligent cement-adding system can realize the precise control of the desired cement ratio and the filling concentration.Through automatic decision and control of fault,the automatic transport switching between tailing filling and tailing ponds can be realized.The system has the advantages of small site area,simple structure,convenient management,low investment and low operation cost.It has a certain reference for similar small or medium underground mines.
    Stability Analysis of Ore Pillar Recovery Based on FLAC3D
    ZHAO Ying-Gui, YOU Xun, YUE Guo-Jun, WANG Chun-Ren, LIU Xiang-Xin
    2014, 43(08):  19-23. 
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    The gob group in a gold mine owns the characteristics of age-old goaf,unstable mine rock,and complicated residual resources.In order to efficiently and economically realize recovery of high grade residual ore pillars in safety in goaf,the scheme design for recovery of ore pillars and residual ores within wall rocks was given,based on on-site survey,tests and economic analysis and combined with production capacity,recovery rate of residual ore,and construction difficulties etc.Flac3D inversion is adopted to analyze the whole procedure of the residual ore recovery scheme,and several sets of simulative monitor points are arranged within the adjacent pillars,roof and floor and artificial pillars in the area of residual ore.Some indexes of stress,strain and plastic zone before and after recovery of residual ore are obtained by numerical simulation.Through the comparative analysis,the gob stability before and after disturbance resulting from residual ore recovery is evaluated to verify the reliability of the mining activity.The evaluation method and conclusions have reference value to following case of residual ore recovery and the similar mines.
    Optimization of Ore Caving Distance in Mining Stope of Danyin Gold Mine
    LIN Jia, ZHAO Wei-Hao, ZHANG Feng-Peng
    2014, 43(08):  24-28. 
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    In overall mining methods，the stability of the roof is very important，which can directly affect the mining operation proceed.Based on the actual situation of No.2608 mining stope in Danyin gold mine，the ore caving distance at the mining stope is optimized.A proper caving distance can guarantee mining work processed smoothly，and also improves the mining efficiency.FLAC3D is adopted to establish the model of the mining room.The raise tunneling is carried out firstly，and then moved along with the ore vein，The stresses of roof at 2 m,3 m,4 m，are analyzed to get the stress distribution and stress concentration area.It is concluded that 3m is the best distance of ore caving.The research result provides a scientific basis to the actual production of the mine.
    Support Design and Analysis of Large Section Roadway in Extremely Thick Coal Seam
    ZHANG Xiang-Dong, 吕Jin-Wei , ZHOU Xin-Qing, GAO Fei
    2014, 43(08):  29-32. 
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    For roadway driven in extremely thick coal seam，there are all coal seam around surrounding rock.In order to further study the deformation and failure characteristics of coal mass in extremely thick coal seam，to determine the effective support forms and parameters and ensure the safety in production，a roadway at Nanyangpo No.5 coal seam is chosen as a research object.It is a large section roadway with cross section form of circular arch 4.3 m wide and roof 3.4 m high.On the basis of determination of the roadway shape and size，roadway supporting design is made.Combining with the field monitoring and numerical simulation，an anchor-mesh-cable support is proposed.Engineering practice shows that：this method can effectively control the deformation of coal rocks around the roadway with good supporting effect.The two-side and roof displacements of roadway have been effectively controlled.The roadway deformation is leveled off in the short term.As well，the supporting cost is greatly reduced and the support period is reduced with anchor rod and anchor cable.This support method owns a high practical value and should be actively popularized in production.
    Application of Combined Caving Method in 92# Orebody of Tongkeng Mine
    SHI Fu-Wen, LI Ming, LUO Xian-Wei, WANG Ming
    2014, 43(08):  33-36. 
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    There are a wide range of overlapping areas between 92# and 91# orebodies.During mining activities of 91# orebody,many goafs were formed in the overlapping area with 92# orebody,which develops a loose collapsed circumstance and causes mining technical condition of 92# orebody be exceptionally complicated due to huge goafs and numerous caving.Some stopes are faced with problems like only one access to stope in upper ore medium levels with goafs on the three sides,two accesses in central levels and whole accesses in nether level,so it is difficult to realize mining with a single open stoping method or caving method,and it may accompany with low recovery ratio and be susceptible to geostress and upper ash.Taking T106 stope of 92# orebody as a test case and with full use of the previous engineering,T106 stope is extracted efficiently and safely by cutting off top geostress with combined caving method based on mining experiences of caving and open stoping method,which ensures mining safety below.It provides a technical reference for other stopes with similar mining conditions as 92# orebody.
    Analysis and Exploration on Related Influence Parameters of 1102 Fully-Mechanized Mining Work face Trial of Wachangping Bauxite
    XU Xiao-Qian, XIANG Long, SHAO Guo-Jun, ZHOU Qi
    2014, 43(08):  37-40. 
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    The mining conditions in Wachangping bauxite are similar with that of the coal mine，and its mining methods can draw lessens from coal mining experience，that is，introducing the fully-mechanized mining technology to improve labor productivity and reduce security risks.Due to higher quality of bauxite required by the alumina plant，the relevant parameters of feasibility for fully-mechanized mining of bauxite are demonstrated and analyzed based on the strict control of mineral products grade and aluminums-silicon ratio.It is the first time for metal mine to adopt the fully-mechanized mining technology in China，so its adaptability should be tested.The dip of ore body at 1102 working face of Wachangping bauxite mostly lies between 15° and 30°，with the average angle of 21°，and the ore hardness coefficient is mostly from 0.47 to 1.8.The geological structure of ore body is simple，and its roof and floor conditions are very close with that of coal mine.At the same time，the comprehensive analysis and comparison on the chemical composition of samples during the tunneling process and the geological data show that if the mining height of 1102 working face is 2m，the content of Al2O3 in ore-body will be more than 60% and the aluminum-silicon ratio (A/S) will be more than 5.These two main indexes can meet the requirements of alumina plant.Therefore，according to the mining experience of coal ore and the related influencing parameters，it is feasible to adopt fully-mechanized mining technology in 1102 working face of Wachangping bauxite.
    Mining Practice of a Humidified Laterite Nickel Deposit
    WEI Zhe, LIANG Jia, LI Xing-Jia
    2014, 43(08):  41-44. 
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    With the mature of laterite Ni deposits′ beneficiation and smelting technique and the serious lack of primary nickel reserves，mining of laterite nickel deposits attract the attention.However，due to the high moisture，rolling topography，high gravel contents，heavy rain and continuous fog in rainy season，it is most difficult to realize mining of humidified laterite Ni deposits.At present，there is no mature experience for reference in mining of humidified laterite Ni deposits.Problems that need to be solved first are how to solve the mining difficulty due to the characteristic of humidified laterite deposit and how to realize mining under the principle of technological feasibility and reasonable economy.The valuable experience that fits for mining of humidified laterite deposit is summarized according to continuous exploration and practice.The mining practices of humidified laterite Ni deposits are mainly introduced，including the field experiences in the key parts like stripping，development，mining and ore blending.The selection of mining equipment and the equipment configuration are present.
    Non-linear Combination Forecast Model to Predict Surrounding Rock Deformation in Deep Buried Tunnels
    GAO Ning, PAN Chuan-Jiao, LI Jian-Gang
    2014, 43(08):  45-48. 
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    Affected by stress distribution，groundwater，opening mode，etc.，the surrounding rock deformation of the deep buried tunnels show nonlinearity in displacement series height.Thus，the non-linear combination model based on the deformation information fusion was proposed.In this model，based on the individual forecast data of GM (1，1) and RBF，and with the use of the neural network，the weight of each model among the combined model was optimized to build a nonlinear combined forecast model.Then，the non-linear combination forecast model was applied to predict surrounding rock deformation in deep buried tunnels.Meanwhile，non-linear combination predictions were contrasted with simple average weighting combination and the optimal linear weighted combination.The results showed that compared with the traditional weighting method，the non-linear combination forecast model has a higher and more reliable precision，and owns a more stable prediction result.It is of a certain theoretical and practical significance in surrounding rock deformation prediction for deep buried tunnel.
    Surrounding Rock Stability of the Roadway Driving Along Gob and its Corresponding Control Technology
    ZHANG You-Qian, ZHOU Jian, WANG Qi, SUN Yu-Liang
    2014, 43(08):  49-52. 
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    Due to the unique structure of isolated coal pillar，there are many problems in roadway driving among isolated coal pillar，such as high concentration of stress，low integrity of surrounding rock，and tough job in controlling the surrounding rocks.The model of the roadway driving along the gob is put forwards.Taking a mine as a case，the isolated coal pillar totally lies in the broken zone and plastic zone.There is no elastic zone for the pillar.Through PFC2D partide flow code simulation，it is obtained that the whole pillar can be divided into failure zone and plastic zone.The range of failure zone on both sides of roadway is about 2.5 m.Anchorage zone needs to be beyond failure zone.Thus，rib cable is needed to control surrounding rock.The relationship between supporting resistance and fissure development is obtained.It suggests that compared with no support，a certain support can control the development of fissure effectively.Nevertheless，when support resistance reaches specific value，increasing support resistance has little effect on controlling fissure development.Through field monitoring and comparison of the surrounding rock deformations under the condition of different support patterns with support or not，it is obtained that layout of the rib cables at walls will significantly reduce the deformation rate of surrounding rocks by 10 mm/d to 15 mm/d，which can effectively control the deformation of surrounding rocks and make sure the normal service of roadway.
    Selection of Pipe Network Parameters and Pumping Pressure in Paste-like Filling System
    XIAO Li-Bo
    2014, 43(08):  53-56. 
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    Hunan Shanxing Antimony Industry Co.，Ltd.is planning to recover the shallow ore residues，and make backfilling with high concentration of paste-like filling system.The physical and mechanical properties of tailings backfill body selected from Tin Mine are tested in the laboratory，and its compressive strength and bleeding rate at different proportions and different concentrations are measured.A suitable filling material ratio for mines is determined to be 1∶2∶8 (cement：fly ash：classified tailings)，and its mass concentration is from 70% to 76%.Through computing transporting parameters of pipelines，a pipe with outside diameter of 0.114 m，and wall thickness of 0.007 m is selected.A series of parameters are concluded as the critical flow of paste-like slurry 0.97 m/s，hydraulic gradient of 885.92 Pa/m，maximum pipeline transport resistance 1.53 MPa，starting pressure of industrial pumps 2 MPa，and minimum pressure of the pump 3.53 MPa.Then，a suitable paste-like filling system for Tin Mine is built，which provides a guarantee for mine backfill.
    The Problems and the Analysis of Incremental Internal Rate of Return in an Expansion Project of a Low Grade of Sulfur Mine
    WANG Xiang-Lin, JIN Sheng
    2014, 43(08):  57-60. 
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    Economic evaluation on expansion project of a low-grade sulfide mine was made.According to the evaluation system of “with new project” and “without new project”,two opposite evaluation findings were obtained by computing two indicators of the incremental internal rate of return and the net present value of the incremental project respectively.The findings showed that as non-renewable and easily-exhausted resources,the mine has a constant reserve.At different calculation period of “with new project” and “without new project”,multiple internal rates of return were emerged,so the indicators have no reference value.Through statistical analysis on benefits and costs of the project,some projects including the original mine stripping,buildings and general plan and others that are treated as salvage according to a certain proportion,along with new investments,are considered as the total investment.Economic evaluation on the new project showed that this is a good approach and it can meet the requirements of the evaluation system.
    Increasing Granular Uniformity of Grinding Product from Meishan Iron Mine
    YAN Liu-Xue
    2014, 43(08):  61-64. 
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    Aiming at the “more of the two ends，less of middles” distribution phenomenon of grinding products，Meishan Iron Mine Dressing Plant uniting with Jiangxi University of Science and Technology carried out both laboratory test and industrial test to increase the uniformity of grinding products by optimizing the grinding parameters. Industrial tests are processed in 4# series of the plant for six months. During this period，based on the results of the laboratory test and the process survey，the grinding parameters including the steel ball size and matching，medium filling rate，grinding concentration，sand returning percentage and concentration of overflow are entirely optimized，combining with field production experience. After the optimization，for the ultimate grinding products in 4# series (overflow of second classification) at the fineness of about 0.076 mm passing 70%: 300~10 μm fraction(qualified) yield increased by 18.05%，and -10 μm fraction(over grinding) yield decreased by 1.60%. Separation index comparison of second classification overflows from 4# series optimized and 3# series not optimized in laboratory conditions is carried out. The results show that the former iron concentrate yield and recovery are increased by 9.54 and 6.60% respectively. In addition，after optimization of grinding parameters in 4# series，steel ball consumption，energy consumption of grinding，temperature of pulp in mill and also the noise from mill running have been decreased to some extent. To sum up，the achievement of grinding parameter optimum in 4# series should be put into promotion in Meishan Iron Mine Dressing Plant.
    Beneficiation Experiment on Oleic Acid Flotation of Bauxite Ore Collaborated with a New Synergistic Agent
    CAO Xue-Feng, GAO Jian-De, LIU Run-Qing, ZHU Yi-Yang
    2014, 43(08):  65-68. 
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    In view of problems of low efficiency and large dosage of fatty acid as collector in desilication by direct flotation of bauxite，a new synergistic agent DT for fatty acid is prepared to enhance the collecting performance. Conditioning tests of coarse flotation for desilication was carried out on a low Al/Si ratio diasporic bauxite using oleic acid synergist with synergistic agent. The results show that the optimum ratio of DT to oleic acid is 2∶8. Adopting this ratio，Al2O3 recovery of rough concentrate by using DT + oleic acid at 500 g/t is 8.90 % higher than that by single oleic acid at 500 g/t，while dosage of oleic acid should be increased to 800 g/t to achieve the same concentration index as mixture ratio of DT + oleic acid at 2∶8. The closed circuit operation on the basis of rough concentration and open circuit process are carried out. It is shown that using sodium carbonate as pH modifier，DT + oleic ratio of 2∶8 as collector，at the grinding fineness of 74 μm passing 93%，Al/Si ratio of the ore is increased from 3.27 to 8.13 with Al2O3 recovery of 76.67% through one roughing，two cleaning flotation，while the total dosage of DT + oleic acid is only 800 g/t. To sum up，the synergistic agent DT can significantly increase the performance of oleic acid.
    Vanadium Extraction & Consumption and Emission Reduction Process of Stone Coal in Shaanxi Wuzhou Mining Co.，Ltd.
    WEI Qing, LI Gui-Ying, DAI Zi-Lin, KONG Zhen-Xing, WANG Hu
    2014, 43(08):  69-73. 
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    On account of the shortcomings of high consumption of sulfuric acid for leaching, lime for neutralizing leaching solution and water during the process, as well as large emission of tailing, both laboratory and pilot experiment are conducted on returning and reuse of residual acid by adding to solution. Effect of the accumulation of V2O5 in leaching solution on leaching efficiency after residue acid returning in laboratory scale is investigated. Lime consumption for neutralization and the output of filter residual before and after neutralization on residual acid returning is compared. Pilot experiment is based on laboratory experiment. Appropriate fresh sulfuric acid and the returning acid are added into solution when V2O5 concentration is 8~18 g/L, only fresh acid is used when V2O5 concentration is above 18 g/L, and only returning acid when the V2O5 concentration is less than 8 g/L. By this method, consumption of sulfuric acid, lime and water during leaching-neutralization process are decreased by 22.1%, 16.3%, 71.4% respectively, also the residual solution output decreased by 15.3%, which indicates that the residual acid returning technology can significantly lower the consumption and emission.
    Mineral Processing Experiment on Iron Removal and Whitening of Feldspar Ore in Shandong
    ZHANG Xin, ZHANG Ling-Yan, HONG Wei, LIU Xin
    2014, 43(08):  74-78. 
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    A feldspar ore in Shandong province belongs to high-Fe feldspar ore，and ferrum mainly exists in form of iron minerals，mica，pyrite，and Fe-bearing alkali metal silicate. Experiments of iron removal and whitening were carried out in order to obtain high grade potassium feldspar as raw material for ceramic industry. Based on the ore property，the experiment was carried out through the process of grinding，desliming at 20 μm，magnetic iron removal by high gradient magnetic separation，pyrite removal by flotation using ethyl xanthate as collector，mice removal by flotation using lauryl amine + kerosene as collector，iron content alkali metal silicate removal by flotation using ZL-1 as collector. Through the experiment，feldspar concentrate with yield of 76.24%，Al2O3 recovery of 80.31%，Al2O3，K2O+Na2O，Fe2O3，content of 16.05%，12.50%，0.09%，whiteness of 67.26% is achieved respectively，which can reach the first-grade K-feldspar quality standards for ceramic industry.
    Geochemical Characteristics and Geological Significance of the Qinggangping Granite in the Western Henan Province
    LIU Qing-Quan, ZHANG Yu, LI Bing, ZHANG Zhi-Hui, ZHANG Chi
    2014, 43(08):  79-82. 
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    The magma source，diagenetic environment and diagenetic mechanism of Qinggangping Granite were analyzed from aspects of the geological features，the petrography，the geochemistry characteristics of major elements，trace elements and rare earth elements.The results indicated that w(Na2O)+w(K2O)，AR，σ and average value of A/CNK varies from 6.51% to 8.67%，1.99 to 3.57，1.94 to 2.60 and 0.97，respectively，which means the granite belongs to calc-alkaline and metaluminous rocks.The magma experienced greater crystallization differentiation during the evolution period and the ratio of LREE and HREE is between 5.74 and 11.75.δEu and δCe values from 0.63 to 1.05，and 0.79 to 0.85，respectively，which means that the granite has weak negative anomalies of Eu and Ce.Th，U and high field intensity of Hf in the granite show relative enrichment，while Ba，Ni and Ti are at relative loss.The magma source of Qinggangping Granite is un-weathered igneous' remelting in the crust，and is formed in the post collisional orogenic environment as granites of type I. Qinggangping Granite|The ore-forming environment|Diagenetic mechanisms
    Study of Geochemical Characteristics and Prospecting Significance of Polymetallic Mine in Danba
    CHANG Xin, WANG Quan-Feng, LI Cheng, ZHANG Xiao-Pan, PENG Tao
    2014, 43(08):  83-86. 
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    Based on the understanding of geological characteristics and geochemical background characteristics of Danba area,the lower limit value of single element anomaly for 16 kinds of element is determined by adopting the mean plus the standard deviation of two times,through analysis and processing of 1∶50 000 stream sediment geochemical survey data.Based on this,five comprehensive anomaly areas were delineated respectively,called Menzigou comprehensive anomalous area,Shibanpeng comprehensive anomalous area,Ganluoba comprehensive anomalous area,Wali comprehensive anomalous area,Kongyu comprehensive anomalous area.It is considered that this five integrated anomaly zone has good ore-forming condition,and has a potential value in further ore-prospecting.Combined with regional geology and mineralization conditions,the geochemical characteristics of mineralization in the area were inferred and forecasted,and the water geochemical prospecting marks of several main minerals of copper,lead,zinc,gold,and silver are summed up.It is considered that the enrichment of gold has a relation with hydrothermalism.It is controlled by fracture belt,and generated at composite parts of fracture structure.Lead and zinc mainly occur in the ore bearing quartz veins.This research will provide guidance for the next exploration work.
    Mineral Resources Security Based on the Geological Survey and Assessment ——Taking a Copper Mine in Central Tibet as a Case
    LIU Bing-Li, WANG Jian-Wei, GUO Ke, LIU Hong-Jun, LUO De-Jiang
    2014, 43(08):  87-90. 
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    Based on the distribution of mineral resources and geological background in central Tibet area，eight evaluation areas are divided.With copper mine as the research object，five A-level indicators，and 12 B-level indicators are constructed.The entropy method is adopted to determine the index weight objectively，and the final complex value was obtained by multiplying the index weight and the index data.According to the assessment scores of each district，the security level of copper resources in the central region of Tibet is analyzed.The conclusions are as follows: copper minerals at Gangdisi-Nianqing Tanggula copper ore belt has a better security level，and copper mineralization at north and south sides of the copper belt is relatively weak; copper minerals in central region of Tibet are distributed into two centers，that is，Xietongmon County and Lhasa City as the center spreading to the surrounding area respectively.The research results can be promoted and applied into the security level study of mineral resources in other areas. Geological survey|Mineral resources|Security|Entropy value method
    Geochronology and Significances of Bima Formation Andesite of Shannan,Tibet
    YAN Guo-Qiang, DING Jun, HUANG Yong, WANG Xin-Xin, ZHANG Kai
    2014, 43(08):  91-94. 
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    The occurrences,morphology of zircon,geochemistry and geochronology of andesite sampled from the upper section of cretaceous Bima formation emerged in Nuri mining area of Shannan,Tibet were analyzed in detail through the field macroscopic description,cathodoluminescence images of zircon and LA-ICP-MS to zircon.The results showed that Bima formation andesite has a comformable contact with underlying Mamuxia formation volcanic rock.The cathodoluminescence images of zircons showed that the zircon have better crystal form and clearer oscillatory band with ratio of w(Th)/w(U) greater than 0.1,which indicated that the zircon is a typical magmatic origin rock.Zircon with the U-Pb concordant age of 92.04±0.71 Ma（MSWD=0.74）belongs to the late Cretaceous epoch which represents the ore-forming time of Bima formation andesite,also represents that the eruptions of Sangri Group volcanic rock lasts from late Jurassic epoch to the late Cretaceous epoch.The accurate zircon U-Pb chronology evidence greatly constraints the activity time of Sangri Group arc volcanic rocks.Meanwhile,it implies that the Nuri deposit suffer from many large-scale and sustaining magmatic activities since the late Jurassic epoch.
    Geochemical Characteristics of Sulfur and Lead Isotopes of the Polymetallic Deposit in Mabugang
    SUN Ning, LUO Wei, KONG Fan-Qian-1, WEI Long-Ming, WEI Hong-Jun
    2014, 43(08):  95-98. 
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    According to the S,Pb isotope survey results of the six pieces of ore samples from the polymetallic deposit in Mabugang,the parameters and graphic of S,Pb isotopes were calculated by Geokit software,to discuss the source of ore-forming materials.Results showed that: the δ34S of sulfide mainly varies from -4.6‰ to +3.2‰,which reflects the composition characteristics of magmatic sulfur.δ206Pb/δ204Pb of Pb isotope among minerals is from 18.6 to 18.8,δ207Pb/δ204Pb is from 15.7 to 5.8,and δ208Pb/δ204Pb is from 39.07 to 39.25.All these display a normal lead character,which are similar to the lead isotopic composition at the upper crust of orogenic belt.In summary,the analysis indicated that the metallogenic sources of Mabugang polymetallic deposit mainly come from the upper crust.Its tectonic background is under cratonization action,and is basically consistent with the actual tectonic environment of mine field at active continental margin.
    Integrated Safety and Monitoring System of Coal Mine Based on the Multi-windows
    HE Zhi-Fen, SUN Jiu-Yun, QIU Yin-Guo
    2014, 43(08):  99-102. 
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    At current，the informatization level of coal production industry in China is lower，and the personnel for safety supervision has a heavy working load.These bring big difficulty in realizing the real-time supervision and management.In view of this issue，and based on the deep analysis of measures in safety for coal mines at home and abroad，the Internet of things and the Virtual reality are rationally jointed to develop a new system for real-time perceiving and pre-warming of coal mine safety.The variety of safety information can be obtained by the Internet of things.How to realize the integrated monitoring of safety information for the whole mine is an issue that should be resolved in time.The system makes full use of the multi-camera control characteristics of Unity 3D.3Dmax is adopted to build 3D virtual scene by modeling and rendering.With the aid of multithreading technology，the parameters updating of each sensor is achieved to realize the multi-widow integrated monitor of mine environment.The research indicates that this system can achieve the real-time monitoring of mine environment and device parameters for a coal mine，and also position and analyze the movement tracks of personnel underground. Coal mine safety|Multithreading|Multi-window|Synchronous monitoring|Unity3D
    An Evaluation Method of Mine Landslide and Deformation Trend based on Three-dimensional Laser Scanning Technology
    HAN Ya, WANG Wei-Xing, LI Shuang, LIU Sheng, ZHANG Xin
    2014, 43(08):  103-107. 
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    Mine slope disasters always occurred in recent years.Due to the complexity of the mine landslide disaster,it is difficult to make effective monitoring and research.To safely and effectively monitor the safety status of the mine slope,three parameters of slope are measured by the advanced three-dimensional laser scanning technology,including the earthwork based on triangular mesh,the slope gradient based the point cloud data,and contour distribution based on mesh grid.Then the state of the slope is respectively analyzed from the three aspects above.It is one-sided to determine the state of the slope based on a single measurement parameter.To overcome the one-sidedness,a fuzzy comprehensive evaluation method is proposed,based on the three measured parameters.In this method,the factors of earthwork,slope gradient and contour distribution are set as evaluation factors,and the membership of each factor are determined based on three factors share in the proportion of all factors.Based on this,the slope state is evaluated by using the formula proposed.Therefore,slope deformation trends can be more comprehensively determined by this method.The method plays an important role in warning the slope disaster. 3D laser scanner,Point cloud,Slope,Earthwork,Slope gradient,Contour
    Dual-way Long-distance Pipeline Transport of Water and Iron Concentrate,Dry Tailings Stockpiling Technique
    NING Hui-Dong, MENG Li-Fang
    2014, 43(08):  108-110. 
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    The integration and application of dual-way long-distance pipeline transport of water and iron concentrate,and dry tailings stockpiling is an integrated science technique including fluid mechanics,ecological environment,mine safety etc.and has been successfully applied in Baotou Steel corp.The integration and application of the technique solves the bottleneck problem that industrial water restricts the development of Baotou Steel Mining Area.It modified the traditional railway and highway transportation for ore and the traditional tailings stacking mode of damming at surrounding.Also,it realized the strategic transfer of Baotou Steel raw materials base,and the efficient development and utilization of low grade ore respectively.A new model of green and efficient development and utilization of metallurgical mineral resources in China was established,which created conditions for re-utilization of rare earth resources remained at tailing pond.This technique has reference for tailings stockpiling and pipeline transportation construction and plays a leading role in exploring mineral resources in the high-cold water-deficient region.It also is of significance in improving the people's livelihood and ecological protection,keeping resource and environmental protection and production safety,and enhancing the competitiveness between enterprises.
    Research on Three-level APF Based on LCL-filter
    WANG Rui-Hai
    2014, 43(08):  111-115. 
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    Part of hoister system in Yongcheng coal mine adopt DC motor speed control devices,which easily brings about harmonic wave and pollutes the grid.To solve this problem,a three-level active filter based LCL filter is developed to reduce harmonic wave.With a diode-clamped three-level topology,the device makes the resonant inhibition through active damping method performed by a capacitor current feedback,and applies the intelligent PSO algorithm to the LCL filter parameters design.The theory and methods used in this paper are proved to be correct and feasible by simulation,which can effectively reduce the harmonics of system.The prototype experiment showed that the developed active filter effectively compensated for harmonics produced in the DC hoist system and controlled the grid harmonic content within 5% to meet the national standard.
    Analysis of Slope Sliding Type and the Slope Angle Optimization in Yinshan Mine
    ZHONG Chun-Hui
    2014, 43(08):  116-119. 
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    With Yinshan mine as engineering background,and based on the field investigation of regional geology and the slope sliding type,the sliding mode of high steep slope in Yinshan Mine and the factors for destabilization were analyzed according to the theory of mechanics for slope sliding.Based on this,the integrated stability of each slope were contrasted and analyzed by strength reduction method and FLAC3D numerical method,meanwhile considering the water permeation.The results showed that:the optimal slope angle at section 1,section 2 and section 8 of North-East slope can reach 44°,46°and 45° respectively after optimization.The optimal slope angle at section 3 and section 4 of North-West slope reach 45°and 48°.The optimal slope angle at section5 and section 6 of Western slope is 46°and 44°,and the optimal slope angle at section 7 of southern slope is 44°.The mine design with slope angle of 45° is wholly optimized,which has practical significance on keeping slope stability.Meanwhile,the research provides guidance to safety production of Yinshan mine. High slope|Strength reduction|Slope angle|Optimization
    Supporting Program of “Strengthening Roof and Sides to Control Floor Heave” for Tunnel based on FLAC3D Analysis
    ZHENG Xuan-Rong
    2014, 43(08):  120-124. 
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    The tunnel named 2# cross-hole of Weijiadi coal mine in Gansu province influenced by both of tectonic stress and mining-induced stress is damaged,which shows as large roof subsidence,huge two-side wall displacement and serious floor heave.After repairing for many times,the damaged support has influenced the production and the safety.By the numerical simulation software FLAC3D,based on the analysis of the geological condition and the previous repairing supporting and referring to the pre-existing relative information,one model of the supporting program is built to calculate the safety of the supporting program that is to control floor heave by strengthening roof and sides of the tunnel.The calculation results indicate that the deformation of roof and sides and the floor heave are controlled effectively with the supporting program.The field monitoring results showed that for the soft rock tunnel,the supporting program of strengthening the intensity of roof and sides of the tunnel can control the floor heave in some way.This supporting program is reasonable and feasible,and can meet the requirement of the tunnel safety. Floor heave|FLAC,Numerical simulation|Strengthening|Field monitoring|Safety
    Pillar Critical Failure Condition of Mined-out Zone Groups Based on RG Method
    GUO Sheng-Mao, LIU Tao, CHENG Gang, YAN Wen-Bing
    2014, 43(08):  125-128. 
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    The mined-out zone groups have become one of the most potential safety factors for mines.In view of the mined-out zone′s occurrence，the RG one-dimensional and two-dimensional models were established.Considering the effect of stress redistribution on the stability of the system，the complex problem of the mined-out zone group system instability was transformed to the comparison between the unit instability probability and the critical instability probability.The critical instability probability of the mined-out zone groups under one-dimensional and two-dimensional conditions are put forwards.Mined-out zone 1 and 2 in Qijiaojing Iron Mine were calculated and verified by this method，showing that the calculation results are consistent with the actual situation.It is indicated that the method has a certain practicality to evaluate stability of mined-out zone. RG method|Mined-out zone group|Critical probability|Evaluation
    Grouting Water Plugging Technology of Underground Mining for Water-rich Mine and the Related Case Analysis
    WANG Xue-Feng
    2014, 43(08):  129-133. 
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    The traditional technology of drainage before mining is not applicable for the mine with large water inrush and complicated hydrogeological conditions.Through deep research and development of underground mine water prevention and control technique,roof limestone grouting water plugging technology near ore-body in pit to control water,achieved good results.The general idea of this technique is that limestone filling and compacting the karstic roof fissures near ore-body can connect the limestone to form water-resisting layer.By this method, an inclined waterproof curtain in parallel with the ore bodies is formed to prevent the groundwater flowing into the stope.Combining with the case,the design concept,implementation method and application effect of the grouting water plugging technology for water-rich underground mining are analyzed.According to the properties of ore deposits,ore body and minerals and its hydrogeological conditions in mining area,the engineering arrangement and statistical methods for drilling and grouting volume are demonstrated,and the principles and methods of determining grouting technical parameters,such as the safe thickness of grouting layer,water plugging process design of roof grouting,grouting method,grouting sublevel height,high pressure water test,grouting sequence and grouting parameters,etc.are analyzed.
    Filling Treatment Effect Analysis of Retained Goaf in Iron Deposit
    LU Hong-Jian, LI Jia-Hui, DONG Xiao-Yi, ZHAO Zong-Zheng, PAN Zu-Ying
    2014, 43(08):  134-138. 
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    Based on the finite element theory，the treatment effect analysis of retained goaf in iron deposit was put forwards from the main factors of the safety evaluation on filling mass at retained goaf and the control of surface deformation.Taking an example of a typical mine，and based on analysis of the filling mass′s displacement and stress field′s regularity after filling of gob，the safety factor at sensitive points of filling mass was calculated with Mohr-Coulomb criterion.The surface deformation control effectiveness with filling or no filling after excavation was analyzed through comparison.The filling effect in the iron ore deposits was comprehensively analyzed.The conclusion was made as follows:The vertical displacement of the filling body is 5 times of horizontal displacement.The total filling mass is in the state of compression，and its stress value is less than the compression strength.The safety factor at the sensitive area of the horizontal filling mass is about 5，which satisfies the requirements；The surface deformation after filling governance is reduced to 50%，so the filling effect is remarkable.The treatment effect analysis model of retained goaf established plays a guiding role in implementing the filling scheme and in treating the similar mines on the premise of ensuring the strength of filling mass and the rate of supporting pit roof.
    Analysis of Surface Deformation Caused by Upward Horizontal Slicing and Filling Stoping Method
    WANG Wei, LI Yun-An, WANG Qin-Gang, HU Li-Zhen, LEI Yin, ZOU Ji-Tao
    2014, 43(08):  139-142. 
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    Exploration of underground minerals usually results in surface cracking，surface deformation，and damage to buildings，which has a serious impact on people′s production and life.Surface deformation in mining area is always an important aspect affecting mining safety.FLAC3D software was applied to build a three-dimensional geological model for simulating the surface deformation caused by the upward horizontal slicing and filling stoping in Sijiaying Iron Mine and a contrast with the surface subsidence value calculated by the empirical formula was made.Thus，the general rule and the deformation mechanism concerning surface deformation in Sijiaying Iron Mine were put forwards，and the geological hazards of surface deformation were assessed.The results showed that the upward horizontal slicing and filling stoping method effectively controlled surface deformation and the filling body played an important role in reducing deformation.The contrastive analysis showed that the numerical simulation result is smaller than that by the empirical formulas，but still within a reasonable limit permitted，indicating that FLAC3D is an effective way of predicting surface deformation.The research has important reference value for research and prediction of surface deformation caused by other similar mining method.
    Research on Roadway Stability Control of More Karst Cave Roof with Weak Mud Invasion
    LI Ben-Kui, SU Xue-Gui, LI Hao-Chun, YUAN Hong-Hu, DU Xian-Jie
    2014, 43(08):  143-147. 
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    More karst cave roofs with weak mud invasion are affected by karst caves.More irregular stress concentration occurs when the roofs are under pressure，thus easily resulting in loose cracking，sliding and caving of surrounding rocks and dramatically reducing its bearing strength.Taking No.10 rail roadway of Yongju Coal Industry for instance，the physical and mechanics parameters of coal and rock samples are measured through experiments.The FLAC3D is adopted to simulate the influences of different cross-section shape and support way on the roadway stability，including the plastic zone distribution regularity and the stress distribution and deformation of surrounding rocks.Through the engineering applications and monitoring，the stability of surrounding rocks around roadway under different cross-section shape and support way is contrasted.The results indicate that the arched section jointed with rational support can improve the stress status of tunnel surrounding rocks，better control the failure area of plastic zone，and effectively lower the rock deformation.Also，it can better maintain the stability of the karst cave roof with rocks invasion.
    Construction Mechanism and Application of Key Bearing Layer in Failure Area of Small Coal Mines
    WU Rui, XU Jin-Hai, WANG Zhong-Liang, WU Ji-南, QIN Shuai
    2014, 43(08):  148-152. 
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    In the light of the fact that many underground mine fields are damaged by small coal mines，and in order to avoid serious damages to the limited coal resources，a secondary mining technology after backfilling was put forward based on building a key bearing layer in the failure area of small coal mines.The mechanical model of roof caving impacting on key bearing layer in destruction area was built，and the determining method of the thickness of key bearing layer in the failure area，the choice of backfilling materials，and the layered backfilling method were investigated respectively.The results showed that the key bearing layer with less than 5 m in thickness can ensure the stability of both roof and the coal walls in secondary mining of Pingshuo second coal mine.Inorganic materials were filled in failure areas of the small coal mines by levels to form cutting layer and key bearing layer with different strength，which made them meet the mining requirements of the normal coal seam and reduced the cost.The research results are of great theoretical and practical significance for the coal seam with similar conditions.
    Research on Green Reclamation Technology of the Mined-out Area in Open-air Phosphate Mine
    LI Xiao-Shuang, LI Yao-Ji, ZONG Shi-Rong, WANG Meng-Lai
    2014, 43(08):  153-156. 
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    With the largest open-air phosphate mining enterprise-Yunnan Phosphate Chemical Group Co.，LTD（YPCG) as engineering background，all phosphate mines under YPCG are located in the surrounding area of plateau lake Dianchi with great ecological pressure on the environment.It is essential for enterprises to restore and rehabilitate the ecological system functions of the ecological fragile zone in the mining area.With four phosphate mines of Kunyang，Jinning，Jianshan and Haikou under YPCG as research target，environmental protection as the basic point in the green mine construction，key technologies of land reclamation and ecological restoration for phosphate mines are investigated，based on two links of development and utilization of phosphate resources including the mining and land reclamation of open-air phosphate mines（taking YPCG for instance).Besides，these key ecological restoration technologies are integrated and demonstrated in YPCG green mine construction process.Related research achievements could provide technical or theoretical guidance and demonstration projects for the green mine construction of phosphate industry in China，which contributes important practical and instructive significance to promoting green mine construction. Open-pit phosphate mine|Environmental protection|Land reclamation|Ecological restoration
    Forecast of Water Inrush from Coal Floor Based on Unascertained Measure Theory
    CHENG Ai-Ping, GAO Yong-Tao, JI Mao-Wei, WU Ping
    2014, 43(08):  157-161. 
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    According to the analysis of coal floor water inrush,four main influencing factors,such as geologic structure,floor mining-induced failure depth coal seam dip angle,hydraulic pressure and aquiclude thick,were regarded as judgment indexes to establish the forecast model of water inrush from coal floor by unascertained measure theory.Based on 14 groups of water inrush data in coal face as training sample,the sample average was set as cluster center,and the weight of judgment indexes was determined by information entropy theory.Through calculating the multi-index comprehensive measurement of sample,the classification of sample was judged by the principle of minimum unascertained measure distance,which was used to forecast the floor water inrush.The forecast model of water inrush was used to make forecast on the other four prediction samples,and the forecast values are the same as the measured values.The results show that the forecast method of water inrush from coal floor based on unascertained measure theory has a good practicability and validity.
    Stability of Pillars Recovery in an Iron Ore
    LIU Wu-Tuan, ZHAO Kui, HU Jing-Tao, RAO Zhao-Xun, LIU Ming-Rong
    2014, 43(08):  162-165. 
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    The open stope mining method was adopted in the first section of No.2 mining area in an Iron Mine.The untreated goaf has reached 400,000 m3 and the ore quantity of remained pillar is nearly more than 26 million tons after years of exploitation.In order to fully recover the mineral resources，the mine is planning to recover the pillars.As the untreated mined-out area is large and the remained pillar is the key support for maintaining the stability of mined-out area，the recovery or destroy of part of pillars may induce a certain scale of ground pressure activities which will threaten normal safe production of mine.So before the pillar stoping，the research on security of pillar mining area can guide the implementation of the pillar stoping，and ensure the pillar mining in safety.Combining with the actual situation in an iron mine and based on the theory of stress increment，the combination of engineering geological investigation，laboratory test with numerical simulation is adopted to research the pillar′s security about the first section in No.2 mining area and to determine the safety factor of each pillar.The research results showed that the pillars in the first section of No.2 mining area is in safety，and parts of pillars can be recovered.
    Ventilation Resistance Test of Joint Mining of Close Distance Coal Seams and Failure Rule of Surrounding Rock
    XU Yun-Long, YANG Dong, KANG Zhi-Qin
    2014, 43(08):  166-169. 
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    In recent years，with increasing depth of coal mining，deep coal seam groups are gradually becoming the main producing seam in various coal mines.Differing from the single seam mining，more and more mining joint of coal seams are adopted due to low thickness in parts of coal seam and small space among each seam.Through the theoretical analysis on the test results of the ventilation resistance parameters under mining conditions of close distance coal seams in a mine，it is found that serious leakage phenomenon exists in the place between the airway and the upper closed work face.The numerical analysis on strata behavior regularity of close distance coal seams under the geological conditions indicates that the damage zones caused by the stress of close coal seams mainly concentrate near the end of roadway.The presence of the damage zone inevitably cause leakage phenomenon.The numerical analysis result conforms to that of the field test.Through the analysis on failure law of surrounding rock，that the problems appearing in mining of close distance coal seam is found out，provides a reliable reference for safe production of mines with similar geological conditions. Close-up|Ventilation resistance|Numerical analysis|Damage of surrounding rock
    Beneficiation Experiments of Sericite Recycling from Graphite Tailings
    LI Feng, SONG Yong-Sheng, LI Wen-Juan, CAI Liao-Lu
    2014, 43(08):  170-174. 
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    A graphite tailing contains 6% of sericite. In order to provide basis for comprehensive recovery of this sericite, beneficiation experiments were carried out. According to the properties of the tailing, -19 μm slime with yield of 53.41% were firstly removed by Φ50 mm GSDF-type hydrocyclone with spigot and overflow port at 2 mm in diameter, under 0.2 MPa feeding pressure and 8% of feeding concentration,91.39% of sericite were enriched in sands settlement. Then, the sands with sericite content of 11.75% was treated by adopting the open-circuit flotation process of one roughing and four cleaning with lauryl amine, and sulphuric acid to modulate the slurry pH value to 3 and sodium silicate added properly in cleanings. Ultimately, sericite concentrate with sericite content and recovery of 85.11% and 77.53% respectively was achieved, which can meet the standards for rubber filler. Graphite tailings|Sericite|Desliming by hydrocyclone|Flotation
    Preparation of α-Hemi-hydrate Gypsum with Desulfurated Gypsum from Power Station in Shandong
    YAO Juan, YE De-Wei, ZHAO Lin, XU Chong, LI Tian-Tian, ZHANG Xiu-Ying
    2014, 43(08):  175-180. 
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    The desulfurated gypsum produced by a power station in Shandong is normally sold in lower price as common mixture of cement and the relate product, as well as raw material for making common gypsum product. In order to increase the added value of the desulfurated gypsum products, experiments on preparation of α-hemi-hydrate gypsum(α-HH) by NaCl salt solution at normal pressure were carried out. Based on the crystal water content and crystal microstructure of the product, the process was optimized to finally determine the concentration of salt solution 20%, slurry concentration 20%, natural pH value, and reaction temperature of 100 ℃ for 3 h. Under this condition, the cylindrical crystallization with crystal water content of 8.74% and average length to diameter ratio of 4∶1 were achieved. XRD analysis proved that the main phase in the product is α-HH indeed.