Taxia granodiorite intrusion is located in the southern Dongzhi district，western Jiangnan Proterozoic Terrane（JPT），which is another known granitoid intrusion after Daicun intrusion in this area.This study systematically researched the geological，geochronological and geochemical characteristics of Taxia granodiorite intrusion.The results show that Taxia granodiorite intrusion was intruded at early Cretaceous（~142 Ma），corresponding to the first stage （154~138 Ma） of Yanshanian magmatism in the JPT area.The SiO2content of the Taxia granodiorite samples are between 68.12% and 71.75%，the K2O+Na2O value is 6.15% to 7.88%，and the A/CNK ratios is 0.98 to 1.39，which suggest that the lithology of Taxia granodiorite intrusion is high silica，peraluminous and calc-alkaline Ⅰ-type granite.Trace elements are enriched with Rb，Th，U，K and depleted with Ba and Sr elements.The ∑REE varies from 109.59×10-6to 135.49×10-6，and enriched with LREE and depleted with HREE（LREE/HREE are from 17.37 to 20.73），the visible right-trending REE patter is corresponding to the crust-derived magmatism.Combining geological，geochronological and geochemical characteristics，Taxia granodiorite intrusion was formed in the Yanshanian paleo-Pacific Plate subduction background，its melt was probably formed from partial melting of lower crust with mantle materials addedtion which experienced strong wall rock contamination during its emplacement.
Liyuan gold deposit is located in the tectonic-magmaic-polymetallic metallogenic belt of Taihang Mountain.The outcropping strata are mainly banded gneiss and amphibolite of Neo-Archean Fuping Group. The orebody is generally hand-shaped and mainly occurs in the NNE-trending structural zone.The metal minerals in ore are mainly pyrite，followed by galena，sphalerite and chalcopyrite.The non-metallic minerals are mainly quartz， potassium feldspar， plagioclase and sericite.The precious metal is natural gold （silver-gold ore）. The wall-rock alteration closely related to gold mineralization are mainly silicification，sericitization and pyrite mineralization.The formation of the deposit can be divided into two episodes，including hydrothermal episode and epigenetic episode.The hydrothermal episode is the main mineralization period，which can be divided into four stages，namely，quartz silification stage，quartz-pyrite stage，quartz-sulfide stage and quartz-carbonate stage.Based on field geological survey and indoor analysis，the ore-bearing wall-rocks and strutural ore-controlling raw were summarized，the prospecting mark was specified，and the metallogenic process was preliminarily analyzed. It is considered that Liyuan gold deposit belongs to magmatic hydrothermal altered rock type gold deposit controlled by fracture zone.The results provide certain scientific basis for gold prospecting in this area.
The Huisenwulaxi gold deposit，located in the northern Alxa block，is a prospective area with great potential for exploration.It has important geological significance to discuss the metallogenic characteristics and metallogenic model of the gold deposit.By summarizing the geological characteristics of the deposit，regional geochemical characteristics，results of fluid inclusions and trace elements，preliminary discussions was conducted on the genesis and metallogenic model of the gold deposit.Geochemical and trace element data revealed that the Huisenwulaxi area is characterized by the high gold background content.Permian Ha’ersuhai Formation has played a role of a mineral source layer.The study of fluid inclusion indicated that the temperature of mineralization was between 240 ℃ and 260 ℃，which was an moderate temperature environment.Folds，schistositized zone and structural fractural zone in the area composed the ore-conducting tectonic and ore-containing tectonic.Huisenwulaxi gold deposit is altered rock type gold deposit.Affected by meso temperature magmatic hydrothermal.The metallogenic model of gold deposit is early preliminary enrichment of gold and the initial formation of primary source bed when the crusts of ancient Mongolia sea subducted to Alxa block，along with the magmatic instrusion of the late Permian，the remobilization，migration and enrichment of gold，secondary enrichment of gold deposits occurred in the late stage under the influence of structural deformation and weathering denudation.
The residual goafs after mining operations is a great threaten to underground work and surface building safe.Stability assessment on goafs system helps to guide normal production and prevent disasters.According to pillars’ domino effect，multiple pillars system was constructed，based on which plliars’ strength was calculated and the limitation state equation was proposed.The system’s stability under criteria with different safety factors was estimated by Monte-Carlo simulation method. In a chromite mine，failure probability of multiple pillars system was much higher than failure criteria，which corresponds to the realistic failure.The stability of pillars system was greatly influenced by both pillar bearing capacity and pillar number.
The interaction and response law of overlapping-orebody mining are important factors that have significant influence on mining safety.The overlapping-orebody of Huashugou copper mine in Jingtieshan area where the upper iron orebody adjoins the under copper orebody was chosen as the research objects.Based on the coupled 3D Mine-Midas-FLAC3Dtechnology，combined with practical mining and filling process of the mine，a numerical analysis model for the response of FeV orebody engineering under the condition of copper orebody in the filling section was established.Then the data including displacement and stress of stoping tunnel of FeV orebody were obtained and were used to analyze the mining process of FeV orebody.Results show that maximum excavating perturbation during mining and filling process of research area occurs in 2 865 m stoping tunnel，and the maximum displacement is 2.3 cm，the maximum amplitude of stress is 11.34% and the maximum shear stress is 1.27 MPa，respectively.TheZaxis stress in the center of cavity roof remains decreasing，and it transfers to all round.The shear stress in the center of cavity roof keeps unchanged while it around the edge of cavity changes drastically.During the mining process of test stope，2 880 m and 2 895 m stoping tunnel above FeV orebody are in steady state.Consequently，stoping process can be accelerated to boost productivity，so as to improve the recovery rate of ore.
The orepass is an important project to slide ore，its structure is simple and convenient to use，but after long-tern use，because the ore constantly impact and wear the orepass wall，it is easy to occur the phenomenon of orepass wall collapses.For most mines，there are some difficulties in the maintenance and repair of chute，so it is necessary to choose a safe，effective and reliable technical scheme for chute reinforcement.Aiming at of the disadvantage of existing support methods that occupying the chute with long construction time，a technical proposal for the integrated reinforcement using double-controlled tension cable bundles from the periphery of ore pass to the inside of it was proposed，and the principle of its action is also described.By establishing the mechanical model of double-controlled tension cable bundles，the design method of cable load that satisfied the safety factor was analyzed.Combined with field engineering practice and monitoring data analysis，it’s proved that the double-controlled tension cable bundles can make the collapsed wall stable for a long time after being reinforced，and can save plenty of repairing time by reducing the occupancy of the ore pass.The method for repairing collapse of ore pass wall based on double-controlled tension cable bundles provides a feasible way to solve the problem of repairing large-scale collapse of the ore pass wall in a safe and efficient way.
With the continuous progress of mine production blasting，there is a cumulative process of blasting damage to the engineering rock mass.When the accumulation exceeds its limit，it will cause slope and landslide and so on.Therefore，used the acoustic wave test method in scene and characterizing rock damage by the change of acoustic wave velocity，combined with modeling method of LS-DYNA finite element program to study the cumulative damage characteristics of horizontal engineering rock mass under frequent blast loading.The results show that the damages of engineering rock mass which with abundant joint fissure have a process of continuous accumulation when under frequent blast loading.There have been very few phenomena of rock mass damage happened in the early blasting order because of the saturated state of rock mass.The damage occurs increases gradually with blasting continued practice and it mostly form as the mutation increase of damage degree.The damage threshold of saturated rock should be less than 0.19 and the actual damage occurs should be more than the results of test.The cumulative damage of engineering rock mass under frequent blast loading，it is mainly express on the continuous expansion and coalescence of primary fissures，and the fracture of rock mass is more prone to break through in the case of water cut.
Stope structure parameters selection is the important work after the mining method determined and can directly influence mine capacity，production cycle，mine schedule，mine safety and so on.Taking a Tibet mine for example，based on mining method，firstly，basic parameters，such as joint information were acquired by engineering geology survey and drill core logging.Three-dimensional visualization evaluation of rockmass quality was made on 3Dmine software based on RMR rockmass evaluation method.Secondly，adopting Barton span empirical formula and comparison diagram of Lang B.critical span and Wang J.neural network span，stope critical span was initially identified considering the demand for mining method.Finally，stope permitted exposure area was verified by Mathews stability diagram，and stope structure parameters were determined for different rockmass stability classification in the second phase of underground mining.The specific method and calculation procedure for optimation of stope structure parameters were systematically described in the paper，which can supply the technical reference for similar work in other mines.
With more mines into deep mining，hard rock in high geo-stress shows high energy storage and generates fractures easily by disturbances， and also roadway excavation accelerate surrounding rock cracking or even broken,so the fracturing rock can be cutting by mechanical tools.Those characters make it possible to operate continuous mechanized mining in the hard-rock ore-body.In this paper，Guizhou Kaiyang phosphate mine is chosen as an engineering background，the simulations of the roadway excavation damaging process were conducted by FLAC3D，and the displacement and plastic damage zone of surrounding rock of three shape roadway section were studied.The results show that the damage scale of the rectangular section is maximum，as well as the displacement，and that the displacement damage zone scale of surrounding rock increase apparently with the geo-stress levels increasing.The failure and displacement of surrounding rock decrease first and then increase with the increasing of lateral pressure coefficient.In the high stress level and high lateral pressure coefficient conditions，the surrounding rock of rectangular section tunnel excavation has a greater displacement and larger plastic failure zone,and the fracturing effect are optimum.These results present a theoretical basis for the layout and the design of induced roadway and illustrate subsequent fracturing rock can be cut by mechanical tools.
In order to effectively solve the problems of vagueness and uncertainty，and the conflict between the evaluation indexes existing in the process of rock-soil stability evaluation，a new approach of comprehensive evaluation on rock-soil stability was proposed based on D-S theory of evidence.Firstly，the recognition framework was established，the evaluation indexes were selected，and the basic probability distribution of levels was determined by using the Gaussian membership function.Secondly，the index weight was determined based on the range of basic probability distribution and the mutual influence between indexes and grades.Finally，the stability of rock-soil slope was determined by using the combination rules of D-S evidence theory.Through comparison with the extension method in the basic probability distribution and relevancy of indexes，determination of weight and the revaluation result，D-S evidence theory was used in the workplace of a rare earth mine in Guangzhou.And the results show that the evaluation model of D-S evidence theory is more suitable and more practical，and with higher accuracy.
Due to the small reserves of platinum group metals in China, the contradiction between supply and demand has become increasingly prominent, and the research on the comprehensive and efficient recovery and utilization of platinum group metal resources is very urgent.The flotation method is the main classification methodof platinum group metal minerals，but it is complicated，with long process，large chemicals consumption and high difficulty in recycling.In view of the difficulty in recycling platinum group metals，the optimization of the processing based on mineralogy research is the flotation research priorities.By using joint processes such as float-magnetic joint，heavy-floating combined and mixed flotation process is the key direction for optimization of ore dressing process.Stage grinding，stage selection and microwave pretreatment technology play an important role in improving the selection index of platinum group metal ore.Highly efficient combination collectors and new inhibitors can enhances the recovery of platinum group metals.Due to the lack of systematic research on the separation process，it is necessary to strengthen the theoretical research work of platinum group minerals in the future.
The rationality and complexity of geometric constraint model directly affect the efficiency of model building, and then affect the speed of boundary optimization.To ensure the accuracy and improve the operation speed is the key point of the optimization of geometric constraint model.On the basis of summarizing the common fitting methods, a method of slope contour interpolation and an algorithm for quickly constructing mining cone by simplifying the geometric constraint relation were proposed.Based on the angle inverse interpolation fitting model, the discriminant method was proposed to improve the rationality and efficiency of the mining cone construction of ring search block for constructing the mining cone quickly under the condition of slope angle changing with azimuth and elevation.It is mentioned that the method of redundancy of mining cone removal that simplified the optimization process and improved the operation speed of mining cone construction. On the basis of constructing the value model, a set of nested pits was produced in batches, and the ultimate pit of the mine was selected when applied to an open-pit mine.
Based on nonferrous metals resources characteristics and the background of the 13th Five-Year Plan strategic thoughts，Hunan nonferrous metals industry is faced to the coexistence of opportunities and challenges. By combining resource security with market economy，the study focus on the market supply and demand of nonferrous metals,the annual consumption and production elasticity coefficient of Hunan nonferrous metals market during 2006~2015 was calculated,and the market supply and demand situation in the next five years was analyzed with the elastic coefficient method.The evaluation index named mineral resources supply and demand safety degree was established to analyze the security situation of nonferrous metals resources in Hunan Province.The result shows that there are many problems about Hunan nonferrous metals resources，like low resource utilization，unbalanced industrial structure allocation，low-refined products with poor technology content etc.It is estimated that there will be a serious imbalance between supply and demand in the future and the resource security will be greatly reduced. Based on balancing the pressure of market supply and demand，advice was offered to promote the development of Hunan nonferrous metal resources safety and industrial economy from five aspects.
To explore the influence of magnetized water on rheological properties of paste slurry pipeline conveying，an indoor experiment was carried out.On the basis of self-made L-inclined tube test device，the physical simulation test of gravity flow of paste slurry under different magnetizing conditions was carried out by orthogonal experimental design.The experimental results were optimized and screened in the end.The results show that the rheological properties of paste slurry can be effectively improved by magnetized water.Besides，magnetized water can reduce yield stress and plastic viscosity of slurry with suitable magnetization conditions，which can improve the reliability of slurry pipeline transportation at the same time.Furthermore，contrasting with blank group，when the magnetic induction being 200～300 mT，magnetized time being 15～25 min and cycling rate being 0.5～1.5 L/s,the friction loss of paste slurry is the smallest,the yield stress and plastic viscosity are reduced by 8%~20% and 12%~35% respectively.
Cemented filling body is the key part of filling mining application,and its stability is the basis and premise for sucessful implementation of filling mining.The actual mining activities can produce a repetitive loading and unloading disturbance on the filling body.By studying the acoustic emission characteristics of the backfill damage and failure process under the action of cyclic loading and unloading,the damage evolution mechanism of the filling body can be explored, which can provide the basis for the acoustic emission monitoring technology of backfill.To simulate this stress environment,the RMT-150c electro-hydraulic servo system and the PIC-2 USB digital multi-channel acoustic emission instrument were used to perform multi-stage loading and unloading experiment with 4 sets of samples of cement sand ratio 1
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