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Table of Content

    15 November 2014, Volume 43 Issue 11
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    Optimization of Transitional Scheme from Open-pit to Underground Mining for Large-scale Iron Mine
    LU Hong-Jian, 南Shi-Qing , GAN De-Qing, CHEN Chao, ZHANG Ya-Bin, GAO Feng
    2014, 43(11):  1-6. 
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    It is one of the key technical problems for mines that transit from open-pit to underground mining to confirm transitional scheme from open-pit to underground mining rationally.Taking Miaogou iron mine as the research object，based on the systematically analysis of the stage of the end of open-pit mining and the occurrence of ore body which is outside the boundary，the infrastructure time and annual production capacity are firstly determined after designing the mining scheme of different districts.Then，on the basis of the exploitation status quo and plan，combing with the formation plan of covering layer and mining schemes of hanging wall ore body，four transition schemes were put forward by analyzing the time-space relationship of transitional period.Finally，in order to achieve a smooth transition，such indexes as investment，resource utilization coefficient，smooth capacity coefficient and mining safety coefficient are regarded as the evaluation index of scheme optimization combined with existing norms and standards.Fuzzy comprehensive evaluation theory is used to optimize the feasible schemes，and the transitional scheme determined finally is that the northern hanging wall ore body will be mined by caving method，and the western hanging wall ore body will be recovered by combination of footrill and chute，and then backfill to form the covering layer.
    Research on Synergetic Mining during Transition Period from Open Pit to Underground
    REN Feng-Yu, LI Hai-Ying, ZHOU Sheng-Li, WANG Chun-Xian
    2014, 43(11):  7-10. 
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    During the transition period from open pit to underground mining，a series of difficult problems occur due to the open pit and underground mining unintended mutual interferences，which lead to poor safety condition and low productivity.This problem still has not been solved.Aimed at the normal production model at the bottom of open pit and the hanging-wall of the underground during the period，a coproduction mode of underground induced caving for hanging wall ores was put forward.From the view of extending the time and space needed by the simultaneous mining of open pit and underground，the optimization of open pit boundary and the synergetic production of open pit and underground mining are investigated.Then，the synergetic mining method for open pit and underground are explored.The theoretical analysis and operational experience of Hainan Iron Mine showed that this approach can significantly improve the safety conditions and raise the capacity of ore production in the transition period.
    Optimization of Structure Parameters in Deep & Large-Sized Orebody
    WU Jin, LI Yuan-Hui, SI Cheng-Bin, XU Shuai
    2014, 43(11):  11-15. 
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    Rational stope structural parameters may lead to a favorable mechanic state for the stopes and the stress and strain distribution of the wall rocks may become more homogenized.Under this condition，support workload is reduced and the mining intensity as well as the production efficiency can be improved on the premise of ensuring the stable exploring system and safe production.Based on the geological situation and mining methods of Sishanling iron ore，two-level orthogonal experimental design is made to decide the key five factors affecting the room exploring stability，i.e.room height，room width，stope length，pillar width and pillar filling method.Then，eight experimental schemes are concluded.The finite-difference software FLAC3D is adopted to make numerical simulation on the stope structural parameters of different scheme at panel，and to obtain the feature of the stress，displacement，and plastic zone under different structural parameters.It is preliminarily obtained that the optimal structure parameters which can stabilize the stope is the height of stope 60 m，the length of stope 60 m，the width of room 18m，and the width of pillar 20 m.The calculating results show that the stope length of the roof influences the stress and roof displacement maximum，i.e.the longer the stope，the greater the stress.The compressive stress mainly concentrates on the panel pillars，while the tensile stress concentrates on the roof and the bottom.The results may provide technical support for safe and efficient mining of rooms and pillars within panel．
    Experimental Study and Numerical Simulation of Pre-stressed Anchorage Technology with Hierarchical Multi-time High Pressure Grouting
    XIE Zhen-Hua, YANG Dong, FAN Bing-Bing
    2014, 43(11):  16-21. 
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    In order to treat the broken-rock high and steep slope of open-pit mine and improve the slope stability，the slurry flow of high pressure splitting grouting are obtained by calculating the stress field of hydraulic fracture，based on mechanism analysis of pre-stressed anchorage and high-pressure grouting.The pre-stressed anchoring technique of the hierarchical multi-time high pressure grouting combining with advantages of two techniques above is put forward.Then，the contrastive pull-off tests of anchoring shaped models formed by the ordinary anchor solid and multi-time layered high pressure grouting solid are made.The stress distribution data of anchoring bolt are collected and its stress transmission rule is analyzed.It is concluded that the hierarchical multi-time high pressure grouting technique improved the bearing capacity of the anchoring by 39.25%.Meanwhile，it can avoid from the stress concentration.Finally，FLAC3D is used to build a simulation model.Experiments that the same put-off force bears on four groups of different splitting width and four different heights are respectively made to contrast and analyze the distribution and transmission rule of the internal stress.The results showed that comparing with the ordinary anchorage，the hierarchical multi-time high pressure grouting can bear much more shearing strength.With the increase of splitting，the slurry vein length will be longer，the splitting width will be wider and the stress field of slurry vein will have a more significant effect.These result in better anchoring performance.
    The Effect of Pumping Aid on Paste Pipeline Transportation
    YANG Liu-Hua, WANG Hong-Jiang, WU Ai-Xiang, PAN Gui-Hao, LIU Si-Zhong, LI Hong
    2014, 43(11):  22-26. 
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    The high on-way resistance along the pipeline system usually leads to some problems like pipeline explosions and leakage at joints etc.，which have posed a serious restriction on the development of paste backfill technology.Taking the paste slurry with the poor rheological properties from a copper mine as a case，some pumping aid was added to improve its rheological properties on the basis of achieving the required filling strength and pumping acquirements.Then，contrast was made with the paste without pumping aid，and the effect of time on rheological properties of the paste slurry with pumping aid added was analyzed.The testing results indicated that，the paste made from full tailings conformed to Bingham features.The addition of pumping aid lowered the effect of concentration on rheological properties，which made the concentration of the paste slurry increased to 78% under the condition of meeting the transporting requirements.Combining with the theoretical analysis，the effect of pumping aids on drag reduction and the mechanism of slump loss of paste slurry after a long time were discussed.It is considered that pumping aid has a dramatic effect on reducing on-way resistance along pipelines and decreasing the abrasion of pipeline with less negative effects.
    Artificial Pillar Substituting the Gently Inclined Thin Rich Ore Pillars
    GUO Wang, TONG Yang-Chun
    2014, 43(11):  27-30. 
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    With the rapid growth in fertilizer demand,it is particularly important to improve the recovery of high grade,and high quality phosphate.Yichang phosphate ore is in high grade,and belongs to the gently inclined thin ore.The current mining method results in the loss rate of ore pillar by 25% to 30%.To solve the problem of excessive loss rate,the scheme of artificial pillar substituting the original ore pillars is proposed.Based on the comparative analysis on the bearing capacity and stability of artificial pillar and ore pillar,the compressive strength of artificial pillar under different pillar distribution forms was obtained.The on-site implementation indicated that the scheme of artificial concrete pillar substituting the ore pillar ensured security of the stope after replacement,and significantly improved the recovery rate of the ore.
    Support Vector Machine (SVM) Prediction of Roadway Surrounding Rock Loose Circle Thickness Optimized by Layered Fish
    HU Jun, WANG Kai-Kai, XIA Zhi-Guo
    2014, 43(11):  31-34. 
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    To timely obtain the thickness of the roadway surrounding rock loose circle and take measures to ensure the safety of the surrounding rock，support vector machine (SVM) based on maximum interval algorithm is adopted to make the prediction.Considering that the performance of SVM largely depends on the choice of parameters，the improved artificial fish algorithm to optimize the parameters of SVM is put forward，in order to obtain better accuracy.This method firstly added the idea of layering and crossover mutation to the basic artificial fish algorithm，then optimized the parameters and adopted the SVM to regress and predict for the test data.By improvement of artificial fish behavior and the parameters，the search space is expanded and the stability of global optimization is increased.Problems existing in the artificial fish late optimization such as slow speed are solved.The prediction on monitoring data of a roadway surrounding rock loose circle thickness showed that the model of roadway surrounding rock loose circle thickness has a higher prediction accuracy，which can shorten the search time，increase convergence speed and improve its generalization performance.This research can play a guide role in monitoring the safety of surrounding rock of roadway.
    Controlling Method of Grouting Intensity Number for Reinforced Fractured Ore Rocks
    WANG Heng, WU Ai-Xiang, WANG Yi-Ming, HUANG Ming-Qing, SHEN Xian-Ling, XUE Zhen-Lin
    2014, 43(11):  35-38. 
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    A copper mine ore body in Yunnan Province is soft and fractured，so it is difficult to realize mining by hole drilling.Pre-reinforcement mining-optimized scheme with chemical grouting was introduced.However，in the beginning of the experiment，it is hard to accurately control the experiment，resulting in the problems that chemical slurry was over used.In order to quantize and simplify the control process of quick-setting chemical grouting applied in the copper mine，the Grouting Intensity Number method was applied to the chemical grouting experiment for the study of fractured ore-body.The controlling standard for chemical grouting of a fractured copper mine was established and the grouting effect was detected by the drilling detector.Results showed that the industrial applications of GIN method should fully consider final pressure Pfand volume of chemical slurry Vf per meter.Furthermore，the controlling standards based on depth range of fan-pattern grouting holes were as follows：at the hole depth of from 0 to 8 m，Pf  is less than 60 MPa·L/m；at the hole depth of from 8 m to 15 m，Pf  is less than 95 MPa·L/m；at the hole depth of greater than 15 m，Pf  is less than 160 MPa·L/m.The drilling detector indicated that the diffusion radius of chemical slurry reached 2.5 m and the pore-forming effect had been significantly improved after grouting.Consequently，this study can be used to quantify the grouting control standards，simplify engineering applications and improve the stability of the fractured ore body.
    Acoustic Emission Characteristics and Failure Patterns of a Weak Cemented Sandstone under Uniaxial Compression:Xiaojihan Coal Mine in Shannxi as a Case
    WANG Hong, YANG Tian-Hong, XU Tao, LI Yang, HOU Xian-Gang, ZHAO Yong-Chuan
    2014, 43(11):  39-45. 
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    In order to research the acoustic emission characteristics and failure patterns of the weak sandstones，uniaxial compression tests together with the acoustic emission monitoring tests on specimen from Xiaojihan Coal Mine are conducted.The test indicated that the characteristic curves of the acoustic emission of six specimens were summarized as the splitting type and the fracturing type.For splitting type curves，the acoustic emission events occurred rarely in the linear elastic and stable development of micro-cracks stage，while they occurred rapidly from the later yielding stage to earlier destruction stage，and still existing after the destruction stage.For fracturing type curves，in linear elastic and stable development of micro-cracks stage more acoustic emission events occurred than those of the splitting type curve，and in yielding stage acoustic emission events increased stepwise until the peak strength，moreover acoustic emission quiet period existed before the peak strength.Furthermore，the failure forms can be divided into single shearing failure and X-type conjugate failure.For single shearing failure，the specimens show higher strength relatively，and its form of failure generally corresponded to acoustic emission characteristic curve of splitting type.Meanwhile，for X-type conjugate failure，the specimens show lower strength，and its form of failure generally corresponded to acoustic emission characteristic curve of fracturing type.The results are of great significance for prediction of the roof deformation failure under high intensity mining.
    Study of Tailings Disposal Scheme in Lame Zinc Mine
    ZHANG Kai-Sheng, WANG Chun, CHENG Lu-Ping, WANG Wen-Li
    2014, 43(11):  46-49. 
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    Tailings in dressing plant of Lame Zinc Mine were discharged with low concentration，which caused such problems as high energy consumption，large water-waste，overproof heavy metal and water shortage in production in dry season and so on.Therefore，the current situation of tailing disposals in Lame Zinc Mine was analyzed in detail.Through the analysis of the nature of tailings，the composition and content of tailings were obtained and the tailings are mainly in medium-fine particle.With tailings settling tests，the flocculant dosage by which tailings slurry can achieve good settlement effect were measured，and the process and concentrated indicators of paste preparation were prepared.At the same time，through the slump tests and the loop conveyor of high concentrations of tailings slurry，a reasonable transportation plan was finally determined by calculating the concentration，volume and speed of slurry delivery.A set of the tailings disposal scheme being suitable for dressing plant of Lame Zinc Mine was put forward，that is，tailings slurry with concentration of 70% is considered as paste for transport.The scheme owns a series of advantages，such as water recycling in production，dry tailings stockpiling，less water wastes etc,.So，the scheme can solve the problems of tailing disposal currently faced by Lame Zinc Mine.
    Analysis of Landslide Stability Based on Creep Strength Reduction Technique
    MA Chong, HU Bin, ZHAN Hong-Bing, JIANG Hai-Fei
    2014, 43(11):  50-53. 
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    Based on the traditional strength reduction technique，the creep strength reduction technique of considering creep property of rock and soil medium have been proposed.The FLAC2D geological model of the main slip line profile is established，and the creep aging stability of landslide is studied by using creep strength reduction technique with respect to a landside in Chongqing city.The results show that：①the displacement of monitoring point in landslide leading edge is the biggest，followed by that under sliding bottom when experienced the same creep time.It indicates that landslide damage begins with the leading edge and generally moves to the trail edge along with the sliding surface；②the landslide long-term stability coefficient is 1.18 with considering creep property of rock and soil medium，and it's 1.26 with not，lower by 6.3%.It indicated that creep is not conducive to the stability of landslide.It suggests the stability coefficient 1.18 as the parameter for engineering design and geological hazard assessment.
    Numerical Simulation Analysis of Ground Surface Subsidence During Mining of Baixiangshan Iron Mine under a Riverbed
    LIU Yan-Chao, CHEN Ke, CAI Si-Jing, HUANG Gang, LIU Fa-Ping
    2014, 43(11):  54-57. 
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    In view of the main orebody of Baixiangshan iron mine is located under Qingshan river.In order to guarantee the safe mining，the numerical simulation method is used to build model of the ore body，surrounding rocks and faults.Faults model is built with rock weakening method.The surface and the faults with large influence are meshed，and then the caving and filling on the model are made by the continuously inclined drift stoping method with tailings backfilling to analyze the situation of surface subsidence.Through analysis and calculation，the maximum settlement value at the central river with the X-coordinate 400m is determined to be 0.23 m.According to the simulation results，an approach for grouting reinforcement of faults in risks was proposed.Through the calculation，the maximum settlement value is reduced to 0.15 m.The results verify the feasibility and safety of mining methods and the safety effectiveness of the grouting reinforcement method.
    Mineral Processing Test of a Low-copper and High-sulfur Magnetite Ore in Anhui
    QIU Ting-Sheng, HUANG Xiong, YIN Yan-Fen, FANG Xi-Hui
    2014, 43(11):  58-61. 
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    A low-copper and high-sulfur magnetite ore in Anhui is polymetallic ore with complex embedded relationship.In order to exploit and utilize the ore，the beneficiation process based on the principle of preferential flotation of copper，activating flotation of sulfur，low intensity magnetic separation of iron，desulfurizing by reverse flotation of iron concentrates was tested.The raw ore consisting of 46.62% iron，0.32% copper，20.56% sulfur was treated by four-stage process of copper flotation of one roughing-two cleaning-one scavenging，sulfur flotation of one roughing-one cleaning-two scavenging，iron concentration of one low intensity magnetic separation，and desulfurizing of iron concentrates by reverse flotation of one roughing-one cleaning.Finally，copper concentrate with Cu grade of 17.09% and recovery of 78.64%，iron concentrate with Fe 67.35%，S 0.28% and iron recovery of 41.16%，sulfur concentrate with S 43.69% and recovery of 88.79% were obtained separately.The test conclusion can be used as the basis for designing of the dressing plant.
    Recovery of Copper and Sulphur from High-sulphur and Low-copper Iron Ore in Western Henan
    吕Liang , MA Chi, GUO Zhen-Xu, YUE Tie-Bing, LI Wen-Jun, LIU Lei
    2014, 43(11):  62-66. 
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    A high-sulfur low-copper iron ore from Western Henan Province contains 0.33% Cu，9.84% S and 28.54% Fe，respectively.It belongs to the polymetallic ore with complex mineral composition and embedded relationship，uneven disseminated particle，and a high oxidation degree of copper and iron.Beneficiation study was carried out for determining the development and utilization program.The results showed that at the grinding fineness of -0.074 mm 85%，copper concentrate containing 20.62% Cu with a recovery of 64.98% and the sulphur concentrate containing 43.19% S with a recovery of 91.56% were obtained respectively by the process of copper and sulphur bulk flotation of one-roughing，three-cleaning and two-scavenging，Cu-S separation of one-roughing，three-cleaning and three-scavenging，and middles back to the flow-sheet in turn.Good concentration indexes were gained.The tailings from the bulk flotation contained 26.06% Fe with Fe recovery of 71.33% and the sulphur content in tailings was reduced to 0.68%，which provides good preconditions for the recovery of iron minerals.
    Flotation Study on a Chalcopyrite Containing Easy-floating Calcium-magnesium Minerals
    MU Ying-Ying, SUN Wei, GENG Zhi-Qiang, LIU Run-Qing, GUO Yan-Zhe
    2014, 43(11):  67-70. 
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    There is high content of easy floating calcium-magnesium minerals in a low grade copper mineral，which is apt to be slimed in the grinding process and covered on the chalcopyrite or other mineral's surface，and influences the flotation behavior of copper.In order to realize high efficient concentration of the ore，a mud-mineral separation process on the ore was carried out.The results show that after desliming flotation at the grinding fineness of 52% -74 μm，copper concentrate with copper grade of 18.13% and recovery of 80.86% is obtained through the process of one-roughing，three-cleaning，three-scavenging process and middles back to the flow-sheet in turn for dealing with the slime，and one-roughing，three-cleaning，two-scavenging process and middles back to the flow-sheet in turn for dealing with the products from the flotation cell after regrinding to be 75% -74 μm.With good flotation indicators，this closed-circuit process can be as a reasonable process for concentration of the ore.
    Experiments of Copper and Nickel Recovery from a Copper-nickel Sulfide Ore in Xinjiang
    LI Fu-Lan, LIU Si-Jia, BAI Ya-Lin
    2014, 43(11):  71-74. 
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    The copper-nickel sulfide ore in Xinjiang with uneven distribution of minerals，wide range particle size distribution，and complex embedment，is a low grade natural copper and nickel sulfide ore associated with gold.Beneficiation experiments of Cu-Ni bulk flotation and then separation of Cu and Ni process are conducted in order to high efficiently recover copper and sulfur.Results indicated that，at the grinding fineness of 70% passing 0.074 mm，copper concentrate with copper grade of 22.36% and recovery of 65.33%，gold grade of 115.00 g/t and recovery of 63.94%，nickel concentrate with nickel grade of 6.11% and recovery of 71.25% were obtained through the process of Cu-Ni bulk flotation of one roughing-three cleaning-one scavenging，Cu and Ni separation of one roughing-two cleaning-one scavenging，and middles back to the flow-sheet in turn to deal with the ore.
    Beneficiation Test of Mo-Pb Polymetallic Ore in Shaanxi
    WU Jun-Jie, SUN Yang, GOU Ming-Liang, SU Chao
    2014, 43(11):  75-79. 
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    Mineral composition of a molybdenum ore in Shaanxi province is complex,main minerals are molybdenite,galena,pyrite,and little wulfenite,among which molybdenum,lead,sulfur,gold has recovery value,molybdenum and lead mainly exists in form of sulfide.Beneficiation experiment is carried out in order to high efficiently develop and utilize the ore.The results showed that：at the grinding fineness of 68% passing 0.074 mm,through one molybdenum rough concentration,four cleaning molybdenum flotation of molybdenum rough concentrate at the grinding fineness of 93.75% passing 0.038 mm,molybdenum concentrate with molybdenum grade of 49.24% and recovery of 89.19%,lead concentrate with lead grade of 61.69% and recovery of 83.47%,and sulfur concentrate with sulfur grade of 46.32% and recovery of 68.21% were obtained separately through the process of lead concentration of one roughing-two cleaning-one scavenging,sulfur flotation of one roughing-two cleaning-two scavenging for lead tailings,all middles returns to the flow-sheet in turn.By this method,comprehensive recovery of molybdenum,lead and sulfur is well gained.
    Flotation of Carlin Type Gold Ore from Guizhou with Lime as Regulator
    CHEN Shui-Bo, LAI Wei-Qiang, LIN Hong-Han, FENG Jin-Ni
    2014, 43(11):  80-83. 
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    The gold in a low grade and refractory gold ore of Guizhou is fine disseminated and mainly occurs in sulfide minerals like pyrite，or occurs as monomer gold.The monomer gold account for 81.34% of total gold，and gold in carbonate and silicate occupies 18.66% of total gold.In order to efficiently develop and utilize this gold ore，experiment of gold flotation was conducted with lime as pulp regulator.The results showed that at the grinding fineness of 96% -0.074 mm，gold concentrate with gold grade of 9.41 g/t and recovery of 86.45% was obtained by adopting the process of one roughing-three cleaning-three scavenging，middles from cleaning collected and processed by one roughing-one cleaning-two scavenging process，and other middles back to the flow-sheet in turn.
    Beneficiation Experiments on a Molybdenum Ore in Liaoning Province
    SHAO Kun, ZHOU 南
    2014, 43(11):  84-87. 
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    Beneficiation experiment is carried out on a molybdenum ore in Liaoning province based on the process mineralogy research at the aim of high efficiently developing the molybdenum resources.The results show that，molybdenite granular is fine imbedded in the ore with molybdenum grade of 0.217%，and the valuable elements mainly exist in form of pyrite and magnetite.Molybdenum flotation of two roughing-two scavenging is carried out after grinding at the fineness of 67% -200 mesh.Molybdenum rough concentrate is reground at the fineness of 92.10% -400 mesh，and then molybdenum concentrate with molybdenum grade of 49.43% and recovery of 91.11%，and sulfur concentrate with sulfur grade of 53.00% and recovery of 73.03% are received separately through six molybdenum cleaning，and sulfur concentration from flotation tailings of molybdenum scavenging by one roughing-two cleaning-one scavenging，and middles back to the flowsheet.Both molybdenum and sulfur is ideally recovered，so this closed circuit process is reasonable for development and utilization of the ore.
    High Efficient Separation and Recycling of Mg and Mn for a Rich Magnesia Low-grade Pyrolusite
    ZHOU Yu-Zhao, FENG Ya-Li, ZHU Bao-Hua, GUO Ya-Ning, CAI Zhen-Lei
    2014, 43(11):  88-91. 
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    The traditional separation process to treat the rich magnesia low-grade pyrolusite usually results in such problems as worse pollution and lower efficiency in separation of manganese and magnesia.In order to solve these problems and achieve development and utilization of high magnesium low-grade pyrolusite,and taking a rich magnesium low grade pyrolusite in Guangxi as raw material,mix solution of high pure MnSO4 and MgSO4 prepared by the process of acidizing reduction roasting +reduction of pyrolusite pulp by tail gas (SO2)-combined leaching of reduction products-impurity removal from leaching solution was adopted to make conditioning tests for Mn2+ concentration by NH4HCO3.The results showed that with mole ratio of NH4HCO3 and MnSO4 as 2.25,the reaction time for 60 min,the reaction temperature at 30 ℃,and stirring speed of 120 r/min,separation rate of magnesium and manganese reached 96.96%.The Mn-Mg separation process not only achieve comprehensive utilization of tail gas (SO2) from acidizing reduction roasting,but also effectively separates from manganese and magnesia in leaching solution.
    Study on the Ringing Possibility of Specularite Particles Ranging from 5 to 15 mm in Rotary Kiln in Jiusteel
    MA Hao, CHEN Tie-Jun, HUANG Xian-Bao, DING Chun-Jiang, QU Wan-Gang
    2014, 43(11):  92-95. 
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    In order to exploit and utilize the powdery specularite at -15 mm in Jingtie Mountain of Jiusteel，the ringing possibility during magnetizing and roasting process in rotary kiln was studied based on the analysis of chemical component and softening melting performance of the ore and the reducing coal.The results showed that when the reduction temperature was strictly controlled at range of 850 ℃ to 900 ℃，the softening phenomenon of the ore did not happen，since the softening and melting temperature of the ore and the stage products is at 1 100 ℃ or above.The ore particles ranging from 15 mm to 5 mm are roasted by gas variable diameter kiln with the size from 0.45 m×9 m to 0.65 m×9 m.Under the condition of carbon powder content of 2.0％，roasting temperature at 850～900 ℃ for 2.5 h，charge ratio at 10％，grinding fineness of 80％ -0.074 mm and low intensity magnetic separation field intensity of 100 kA/m，iron concentrate with iron grade of 55% and the recovery of 83% was received，and the ringing phenomenon did not appear in 360 h.Scientific and rational kiln type，stable and reasonable thermal system，and appropriate particle size，can effectively reduce the ringing formation during magnetizing and roasting process of specularite in the rotary kiln in Jingtie Mountain，Jiusteel.
    Application of Soil Geochemical Exploration in the Southern Margin of Mohe Basin
    YANG Yuan-Jiang, SHEN Long
    2014, 43(11):  96-99. 
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    Based on the results of 1∶50 000 stream sediment survey，good anomaly area is locked out in the southern margin of Mohe basin，where the 1∶20 000 soil geochemical exploration work is carried on，and then the preferential areas are revealed so as to find the breakthrough in exploring nonferrous metal mineral.The results show that，the mineralization of lead，zinc and molybdenum are good，and several lead，zinc and molybdenum ore bodies can be confirmed.It provides the prospecting target area and direction.Soil geochemical concentration center and sediment concentration center of lead，zinc and other elements basically fit with.It is shown that,based on the anomalous stream sediment in this area，the soil geochemistry method for searching nonferrous metals is effective and reliable，such as lead，zinc and so on.lead，zinc，molybdenum ore bodies that have been found，are controlled by the contact zone of Guanghua group rhyolite and middle Proterozoic gneissic complex rock.It also proves that the method of soil geochemical exploration is effective in prospecting nonferrous metals in this area.
    Hydrogeochemical Characteristics and Prospecting Implications in Qulong Ore Area，Tibet
    CHEN Ling-Kang, XU Shi, ZHANG Lian, XIA Wei-Wei, WAN Jia-Wei
    2014, 43(11):  100-104. 
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    In the same period of 2008，2009 and 2012，water from inside and outside of Yulong copper area in Tibet are sampled to analyze its heavy metal ions and hydrochemical status.The results show that，the contents of Cu，Zn ions are higher in water with hydrochemical type as sulfate and pH value 5.57.Weathering and dissolution of sulfide results in SO42- anomaly in the water，and this anomaly is positively correlated with Cu2+.Large amounts of heavy metal ions are released from metal sulfide oxidation，and then are enriched with migration of underground water and surface water.Its concentration varies in the same trends with the deposit size and the occurrence position.There exists a genetic relationship between hydrogeochemical characteristics of Cu2+ and copper deposit types and scale.So it provides a good hydrogeochemical signal for exploring this type of ore deposits.
    Geochemical Analysis of Rock Debris in Muru Area，Gerze County，Tibet
    LIU Hong, LI Guang-Ming, ZHANG Zhi-Lin, HUANG Han-Xiao, XIAO Wan-Feng
    2014, 43(11):  105-108. 
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    According to the geochemical data of debris at 1∶10 000 in Muru area，the multivariate statistics methods，like the factor analysis method is applied to investigate the geochemical characteristics of this area.Three element groups are marked out：Sb-Pb-Ag，Cu-Zn-Bi-As and W-Au-Mo.Furthermore，the contour plot of the factor score is drawn.Based on this，the prospecting direction is discussed so as to narrow the range of prospecting target.The geological features of this area indicated that the ore-forming fluid which is related to the gold mineralization sources from magmatic hydrotherm，and migrated from southwest to northeast along the NE trending fault.Besides discovering the gold ore bodies，there is the prospecting potential for finding the magmatic-hydrothermal related Cu-Zn ore bodies in the Muru area.
    Characteristics of Albitization and Albite Breccia in Shuangwang Gold Deposit，Shaanxi Province
    FAN Yu-Xu, FANG Wei-Xuan, FU Yu-Zhen
    2014, 43(11):  109-112. 
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    The characteristics of rock-forming minerals and the zoning characteristics of alteration in Shuangwang Gold Deposit are studied by mineralograpy，electron probe micro analysis and rock chemical analysis method.The study results show that，the content of Na2O in albite is between 7.39% and 12.22%.The chemical composition of Albite is consistent with its end-member component，so it is relatively pure albite with feature of multi-phase mineralization.Due to little change in its composition，sodic fluids may be homologous.Iron content is higher in ankerite，and the components of MnO are more than 0.15% in almost all the samples except for two samples.The characteristics of ankerite are similar to that of carbonatites in Bayan′obo.Associated with dravite，ankerite has characteristics of gas-liquid magma.The albite ankerite breccia may be the factor for magmatic hydrothermal cryptoexplosion in Shuangwang deposit.Albitization in Shuangwang gold deposit has a central symmetry with ankerite alteration.Breccia alteration is maximum，and its intensity is gradually weakened to the sides.The content of Na2O in breccia varies between 9.84% and 8.25%，which has reached industrial grade of albite with high purity.Therefore，albitite existing in Shuangwang gold deposit and tailings has a value for comprehensive utilization.
    Design of Metal Mine Deep Mining Roadway Thermal Exchange Simulation Test Platform
    JIA Min-Tao, CHEN Yi-Hua, WU Leng-Jun, WANG Shuang, JIAN Cong-Guang
    2014, 43(11):  113-116. 
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    Based on thermal disaster control in deep mining,a set of metal mine deep mining roadway heat exchange simulation test platform was designed.According to the similarity theory,the underground excavation roadway is simplified into a cuboid in the test platform.All kinds of underground heat sources were simulated by electro heating film,and downhole high humidity environment were simulated by humidification with humidifier.The refrigerating unit is composed of refrigerating units,air cooler and cooling air duct.The test platform adopts Siemens 300PLC system for real-time monitoring and remote operation,and for real-time data acquisition of process parameters in operation of equipment,and production process.The data collected will be transmitted to the upper computer screen.According to the process requirements,the upper computer is used to make automatic control and operation on equipment,process,and process parameters.The test platform can simulate the real heat and moisture exchange environment in the laboratory and also simulate the change law among tunnel flow field,temperature field and humidity field.It can be used to investigate the cooling effect factor for the cooling system matching optimization and cold in the distribution.It has good practical significance and application value to solve the current problems in deep mining.
    Mine Ventilation Monitoring System Based on WiFi Sensor Network
    REN Yuan, LI Ning, WANG Li-Guan, JIA Ming-Tao
    2014, 43(11):  117-120. 
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    A portable WiFi sensor based on the ultra-low power consumption controller MSP430F149 is designed for the acquisition，processing，storage，and management of various toxic and hazardous gases concentration.The switch and general base station，with optical fiber as the transmission media，is used to establish a WiFi sensor network.This network is capable of realizing transmission and conversion of data acquired by this portable WiFi sensor between WSN and the Internet，providing a solid solution for online monitoring of ventilation environment for the stope and the tunnel especially for both the tunnel face and single end tunnel.Its application can effectively avoid accidents due to blindly operation when necessary parameter concerning the environment is scarce.This network has been applied in certain metal mine and produced satisfactory effects in ensuring safe production and expanding economic interests.Therefore，this network is supposed to be applied and promoted.
    CFD-based Numerical Simulation of Flow Field of and Particles Motion Behavior in Spiral
    GAO Shu-Ling, WEI De-Zhou, CUI Bao-Yu, SHEN Yan-Bai, HUANG Xiu-Ting
    2014, 43(11):  121-126. 
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    In order to ascertain the flow characteristics of spiral and separation behaviors of different mineral particles,numerical simulation of flow field of and particles motion behavior in spirals with diameter of 300 mm,was carried out by utilizing k-ε model for turbulence calculation and VOF model for capturing the air-liquid interface and discrete phase model for the liquid-solid coupling based on the principle of CFD.The influence of spiral interval and feed mass flow on them was discussed as well.The results showed the water velocity isolines exist like obvious bands,its velocity magnitude increases gradually along the direction of spiral depth,and increases gradually from inner to outer along the radial direction.The turbulence kinetic energy appears like ellipse rings in the radial direction,and increases from top to bottom at the outer edge.In the same flow field,the maximum of particle motion speed has negative correlation to its density.When the spiral internal was enlarged,the water depth keeps invariant,however the water velocity and turbulence kinetic energy increased accordingly,and the particle motion speed increased as well,which could accelerate particles banding and separation.The feed mass flow has significant effect on the water depth,flow velocity and turbulence kinetic energy,however it has little influence on the flow distribution characteristics.The particle motion randomness is positively correlated to the factor,resulting in the delay of particles banding with the increasing of feed mass flow,which is disadvantage to the separation process.
    Effect of Expanding Backfills on Controlling Ground Settlement
    HU Lei, REN Gao-Feng, QIAN Zhao-Ming, WANG Li, CHEN Guang-Hai, WANG Yu-Jie
    2014, 43(11):  127-131. 
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    In order to improve the effect of filling method on controlling ground settlement，the theoretical analysis method was adopted to conclude that improving the backfill roof contact rate is the key factor for controlling the ground settlement.Then，in view of the present low roof contact rate，an improved expanding backfill method of replacing traditional cementations and tailings mixture with burnt lime was proposed and the expansion properties of expanding backfill was gained by the experiment.The experiment result showed that the expandable backfill can improve the roof contact rate of filling body and its expansion force can generate some support force on the roof rock.The expansion forces are 1.14 MPa，0.68 MPa and 0.47 MPa when the cement-sand ratios are 1∶1，1∶3 and 1∶5 respectively.Finally，based on the experiments，and taking -175 m stope of western district in Chengchao Iron Mine for instance，the effect of expanding backfills on controlling ground settlement was studied through numerical calculation.The calculation results and theoretical analysis are in good agreement.The calculation result shows that expanding backfill can lower the ground settlement by 94% in maximum.
    Evaluation Method for Occupational Hazards of Confined Space of Deep Mines
    XIONG Li-Xin, LUO Zhou-Quan, WU Chao, SHI Dong-Ping, JIA Nan
    2014, 43(11):  132-137. 
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    Occupational hazard of confined space of deep mines comes from different sources.Due to the discrete data type，it is hard to realize the effective quantity analysis.The occupational hazards data of 173 deep operation platforms and chambers from 8 typical mines were analyzed.The key indexes of the occupational hazards were determined.5 different harm degrees were constructed based on the upper limit，lower limit of single index classification; The weight of each index was determined based on FAHP，and the risk evaluation matrix was built based on TOPSIS.The approaching degree between confined space of 20 deep mines and the ideal solution were calculated.The calculation results showed that the harm degree of the deep working platform is higher than that of deep chamber，and about 27% of the working platform lies at high harm level or more.Therefore the occupational safety protective measures for workers should be strengthened.The method provides a new way for pre-warning occupation hazards of confined space of deep mines.
    Instability Criterion of Rockburst Risk Based on Mohr-Coulomb Strength Theory
    ZHANG Yue-Zheng, JI Hong-Guang, HOU Zhao-Fei
    2014, 43(11):  138-142. 
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    Rock burst is increasingly becoming the dangerous disasters damaging to engineering safety，thus the establishment of an effective criterion to prevent this type of disaster is of great importance.Based on the Mohr-Coulomb strength theory，the stress indicators of impact risk deduced by analytic geometry method is proposed，and the criterion is verified by the triaxial tests of monzogranite rock sample.The research shows that:①The criterion of impact risk and its stress indicator has a good correlation with the rock stability.Specifically，the higher the value is，the higher the probability of impact risk is.②The stress indicator of impact risk can reflect the impact risk degree of rock under a certain stress level，which can comprehensively reflect the influence both of stress parameters and mechanical parameters on the impact risk，and compensate the deficiency of single-index analysis of the maximum principal stress，the minimum principal stress.③It can be employed as a new analysis indicator for the numerical method.The spatial distribution of the stress indicator obtained by numerical calculation is a direct reflection of the rock impact risk in different locations，which provides a predicting basis for rock-burst.
    Determining of Correlation Weights of Index in the Tailing Dam Risk Assessment
    SHI Dong-Mei, YANG Feng-Bao, WANG Xiao-Xia
    2014, 43(11):  143-146. 
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    To solve the problem that the present risk assessment method of tailings dam does not consider the correlation between monitoring indexes resulting in double calculation during the evaluation process，the correlation between the monitoring indexes is considered and converted them into weights，so that the dominant index had the smaller weight，and vice versa.So the problem of double counting can be lowered.An integrated weighting method was used to determine the weights:according to the characteristics that monitoring indexes has different influence on each other，an influencing matrix is established.As the experts information required in the matrix is fuzzy，the trapezoidal fuzzy number is used to describe experts information and to calculate the subjective weights；With features of fuzziness and randomness，the monitoring data are represented by possibility distributions，then the correlation coefficient weighting method was used to calculate the objective weight of every index；Subjective weight and objective weight are integrated by the mean method.Example results show that:the weight calculation method that considers the coefficient of monitoring indexes can reduce duplication in risk assessment，and integrate subjective and objective weights.This method provides the theoretical basis for weighting of each index for tailings dam.
    Advanced Early Warning Detection Ahead of Tunneling in Underground Iron Ore
    LIU Dian-Jun, JIA San-Shi, WANG 恩De, GONG Guo-Hui, CONG Gui-Xin, CHEN Ji-Hong
    2014, 43(11):  147-150. 
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    During the underground tunnel construction process of metal mines,the geological conditions in front of tunnel face vary widely,especially when the goaf or the water-containing goaf occurs,resulting in great safety hazards.In order to ensure the safety and efficiency of mine roadway construction,the advanced early warning research is much needed.Therefore,water bearing fracture zone and goaf left in front of roadway tunnel face in the underground mine -10 m middle are found by adopting the upgraded TEM equipment together with the self-made multi-turn or over multi-turn small coincident loop measuring device,through the sector positioning data sampling method,and using multiple data processing and interpretation method.The results showed that the mine TEM method can be applied in advanced warning detection of roadway tunnel face in metal mines,and can provide technical guarantee for the production safety of metal mines.
    Coal Mine Subsidence Monitoring Based on D-InSAR Technology
    YAO Dan-Dan, WU Kan, HE Qiang
    2014, 43(11):  151-155. 
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    Due to time concentration and large deformation in ground movement and deformation caused by coal mining，there are various limitations in monitoring coal mining subsidence with D-InSAR，and it is difficult to obtain accurate surface subsidence information.In order to apply D-InSAR technology to monitoring land subsidence in coal-mining areas，RadarSat-2 data are processed by “two-pass” differential interference technology.The effects of vegetation factor on the coherence between images were analyzed through experiments，and the influence of monitoring magnitude on the interpretation results of surface subsidence was explored.With Jiulong mine in Fengfeng coal mining area as an experimental zone，the monitoring precision based on D-InSAR technology was analyzed.The results show that vegetation coverage rate is the decisive factor of affecting the coherence between images，and D-InSAR technology can be better used in less vegetation in winter than more vegetation in summer.Subsidence velocity exceeds the range that can be monitored by the satellite and only the deformation of the basin edge can be accurately monitored due to the complexity of geological and mining conditions；when mining subsidence does not exceed monitoring magnitude，the monitoring results by D-InSAR technology are consistent with the usual leveling monitoring data.With the depth of relevant theory and the maturity of processing software，the D-InSAR technology will have a broader application prospect in coal-mining areas.
    Analysis and Evaluation of Water Conservancy Security in Nanhu Mining Subsidence Lands of Tangshan
    GAO Huai-Jun
    2014, 43(11):  156-160. 
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    Water conservancy security in Nanhu mining subsidence land refers to the conservation of lake landscape and downhole production security in Tangshan Mine.According to the geological and mining conditions，the development level of mining-induced fissure is figured out to find the possibility of surface water conduction by the fissure.In addition，the influence of the local caving of steep outcrops on the surface water is analyzed.Besides，it conducts the correlation analysis of water quality between the surface water and the ground water after monitoring the variation of water level.And the variation relationship between downhole water inflow and surface water is also analyzed.The study reveals that there is an alluvium water-resisting layer of about 40~50 m in thickness under Nanhu water storage area，which is composed of clay and sandy clay.With better water resistance，it can prevent the water infiltration in water storage area.What is more，the mining-induced fissure will not extend to the alluvium so that the water resistance will not affected，thus mining-induced fissure and local caving caused by mining will not make surface water sink directly into the down hole.And the correlation analysis among the level，quality and amount of water shows that the surface water has no direct hydraulic connection with water inflow and therefore it is feasible to conserve water in Nanhu mining subsidence lands.
    Re-concentration Test of a Hematite Tailing
    LI Xing-Ping, WANG Yong-Tian, DAI Zhi-Wei, TIAN Kun-Lun
    2014, 43(11):  161-163. 
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    Main ore mineral of a hematite tailing is hematite,and the gangue minerals are mainly quartz.It contains iron of 18.78%,SiO2 of 73.25%,and low content of harmful elements such as S,P,with iron mainly enriched in fine particles.In order to explore the possibility of the development and utilization of tailings,beneficiation experiments are carried out based on the analysis of the ore property.The results show that at the grinding fineness of 95% -42 μm,iron concentrate with iron grade of 64.75%,recovery rate of 78.69% is finally obtained by adopting the closed circuit reverse flotation process of high intensity magnetic separation (background magnetic induction intensity for 1 T) for pre-concentration,one roughing-one cleaning-one scavenging (middlings back to the flow-sheet in turn) to deal with the sample.
    Silver Recovery from a Zinc Hydrometallurgy Residue in Inner Mongolia
    WANG Yu, CAO Jing
    2014, 43(11):  164-166. 
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    There is 217.98 g/t of silver in a zinc hydrometallurgy leaching residue of Inner Mongolia with particle size of 92.48% -75 μm.75.51% silver is present in the form of metallic silver,silver sulfide and silver sulfide inclusions,and more than 90% silver is distributed in -75 μm fraction.Beneficiation experiments of flotation process are carried out in order to high efficiently recover the silver of the secondary resources.The results show that by using activated carbon as carrier of micro-fine silver mineral flotation and sorbent of dissolved silver,silver concentrate with silver grade of 4 084.18 g/t and recovery of 79.63% was obtained on disposing the zinc hydrometallurgy leaching residue with the closed-circuit flotation processing of one roughing,three cleaning,two scavenging,and middlings return to the flow-sheet in order.The process has characteristics of simple,efficient and low cost,and can be the basis for design of silver recovery system.
    Experiment of Rutile Flotation Recovery from a Cu-Mo Tailing
    WANG Yun-Huo
    2014, 43(11):  167-170. 
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    A copper-molybdenum tailing with size distribution of -0.074 mm 68.63% is fine.Rutile is content of 0.31%,and obviously enriched in 0.037 ~ 0.010 mm size fractions,with single liberation degree of 72.80%.Gangue minerals are mainly quartz,and amount of easily sliming chlorite and clay minerals.In order to improve the comprehensive utilization of resources,realize rutile recovery from the tailings at low cost and high efficient,beneficiation experiments on rutile are carried out with no grinding operation,through two roughing-four cleaning-one scavenging,mixing concentrate of scavenging with tailing of first stage cleaning,other middles return to the flow-sheet in turn.Finally,rutile concentrate with TiO2 grade of 64.59% and recovery of 77.25% is received,realizing better rutile recovery index.
    Strength Development of Steel & Iron Slag Cement without Clinker in the Thermal Curing Condition
    CHOU Xia-Jie, NI Wen, WANG Si-Jing
    2014, 43(11):  171-174. 
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    In order to explore the possibility of using Anshan steel slag & iron slag as main raw materials to produce the non clinker slag cement,orthogonal test is conducted to verify different periods of concrete compressive strength with the steel slag to iron slag mass ratio A,ascade mixed grinding fineness B,Ca(OH)2 and gypsum mass ratio C,heat curing temperature D as variable factors.Meanwhile,the XRD spectra of cementitious materials and SEM photo of paste blocks are analyzed.The results showed that：when the A,B,C,D were 1∶2 480 m2/kg,2∶1 and 35 ℃,the cement obtained the highest compressive strength,and its compressive strength were 18.36,26.89,45.32 MPa after curing 3,7,28 days respectively.The strength impact of these four factors on the sample is D>A>B>C.②The early strength of the cement system roots in C-S-H gel and a small amount of ettringite；Its later strength mainly depends on the generation of ettringite.
    Study on the Performance of Eco-concrete with Calcium-silicate Slag from Alumina Metallurgy
    ZHAO Ya-Zhao, LIU Xiao-Ming, LI Hong-Xu, ZHANG Na, ZHANG Hong-Lei
    2014, 43(11):  175-180. 
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    Calcium-silicate slag is a kind of solid waste，which is discharged during alumina extraction from high alumina content fly ash.To reveal the performance of calcium-silicate slag based eco-cement，regarding 32.5# ordinary Portland cement as a reference object，natural sandstone as aggregate，and liquid polyethylene acid as reducing agent，concrete at the degree of C30 & C40 were produced，and also its mechanical properties and durable performance were investigated.The results show that ①the mechanical properties of the calcium-silicate slag based eco-concrete at early age are better than those of the ordinary Portland concrete，but at slow growth in the late.The flexural strength and the compressive strength of the eco-cement mortar cured at 28d reach more than 8 MPa and 40 MPa，respectively.②Compared with ordinary concrete，eco-concrete confers excellent properties of the resistance to sulfate attack and chloride penetration.Eco-concrete cured at 14 d (including 14 d)is about the same to ordinary Portland concrete，but its shrinkage is less than ordinary Portland concrete after 14 d.Eco-cement C40 has excellent resistance to alkali-aggregate reaction.The remaining durable performance of eco-concrete is fairly the same as that of ordinary Portland concrete.③Eco-cement has excellent solidification characteristics for Cr ions.Therefore，eco-cement is superior to the ordinary Portland concrete.