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Firstly, the paper reviews the status quo of mechanical shaft boring technology overseas. Secondly, describes generation and development of shaft drilling technology used in domestic alluvium. Then drilling technology development is divided into four stages: Basic technical preparations ; field application test of drilling process ; mature technology and equipment stage and breakthrough stage. List the drilling method used in western soft rock, small diameter vertical channels in mines, municipal engineering and other mines, as well as technical problems need to be solved. Thirdly, the development of Raise Boring Machine and the difficult in drilling in coal mine was analyzed, and technical issues need to be addressed in the Raise Boring Machine construction is described. Fourthly, the development of full face shaft boring machine is prospected and performances of rock-cutter, slagging, supporting and auxiliary systems are discussed. Through analysis, conclusions are that using suitable mechanical drilling method to construct shaft under different geological and project conditions can reduce the workers in the underground construction, then complete the construction safety and efficiency. [ABSTRACT FROM AUTHOR]

The pertinence and effectiveness of gas pumping for underground coal mining is an important issue for simultaneous exploitation of coal and gas. Its core is the definition and analysis of mining enhanced permeability of mining induced fracture network from the view point of science and technology. In this paper considering the volumetric change of damage coal with cracks induced by coupling of the abutment pressure under different mining conditions pore pressure expansion caused by gas adsorption the mechanical definition of a new word of mining enhanced permeability was obtained. The word means the change in permeability by volumetric change of coal and four kinds of theoretical models were derived. Then an engineering example was studied based on the numerical calculation of the mining enhanced permeability in the overburden rock and coal seam. The result shows that the mining enhanced permeability is able to represent the quantitative influence on permeability of coal caused by the evolution of the cracks and can be the scientific method and strong support for quantitative evaluation of effect on permeability of coal. [ABSTRACT FROM AUTHOR]

In order to know about the composition information of the basic structural units of low metamorphic coals, by means of X-ray diffractometer (XRD) and High resolution transmission electron microscopy(HRTEM), the paper contrastively discussed the arrangement mode of macromolecular structure and the change laws of lignite coal, exampled by Longkou lignite, before and after be fractionally extracted by different solvent. The results reveal that, as the extraction stages increase, the aromatic layer spacing shows a reduction trend, but the length and width of aromatic layer both appear increasing trend. However, these change laws of all the parameters of coal microcrystalline structure are caused by different swelling mechanisms. Comparison by the other extraction residues, the transmission electron microscope images of the raw coal are more clear, and the structure and the arrangement mode of the aromatic layer more uniform. With the increasing of the extraction stages, the clarities of high resolution images of the residues get weak. The macro-molecular structure of the lignite is mainly made up of 2-3 carbon net layers with directional arrangement, and single carbon net layer scatters in local area by the mode of deflection shape, wormlike shape or cross shape. The ultra-micro-pores mainly include the spaces in different BSU or the carbon net layers in the same BSU. [ABSTRACT FROM AUTHOR]

With the global low carbon economy era commences, the reduction and utilization of greenhouse gas becomes a major concern in the world. The reclamation of greenhouse gas CO2 and the new opportunity it brings in the research area of carbon chemistry will become a new hot spot in the research frontier of green catalysis. In this paper, various typical catalytic reaction pathways for enabling direct conversion of CO2 to useful value-added chemicals were reviewed, including oxidation of saturated hydrocarbon by CO2, synthesis of organic acids and esters with CO2 Furthermore, some comments were made regarding the advantages and disadvantages of the catalysts involved, and their underlying reaction mechanisms of CO2 activation by catalysis. Based on these discussions, future work in this category was proposed. The authors believes that, the task-oriented activation of CO2 is the key factor governing the whole process of its chemical utilization, where suitable catalysts with high activity need to be developed, the exploitation of new reaction media and use of new phase state CO2 may greatly enhance the conversion and selectivity of the reaction and hence deserve further investigation, as to the direct use of CO2 emitted from different practical sources, it is quite necessary to develop multi-functional catalysts with desirable adsorption-catalysis activity, so as to meet the requirements from different cases, in addition, the investigation of photocatalysis of CO2, and the characterization and simulation on the process of photosynthesis are beneficial to both the utilization of new energy and the mitigation of greenhouse gas. [ABSTRACT FROM AUTHOR]

Three kinds of experiments on water seepage were introduced in this paper, including homogeneous media physical simulation, inhomogeneous media physical simulation and heterogeneous medium simulation affected by mining, as long as the field detection in a coal mine where a water flood disaster happened during the geo-electrical detection which lasted nearly a month. All these work were done to study the self-potential (SP) characteristics in the process of mine water inrush. Both the homogeneous and inhomogeneous media physical simulation under steady condition indicates that self-potential increases continuously and steadily while water flows closer to the electrical measuring position. Consequently, flow state within the area can be deduced with the self-potential trend lines. Inhomogeneous media physical simulations with and without mining interference indicate that SP curve shapes are different between these two conditions. While SP curve arises steadily without mining interference, they fluctuate a lot under mining condition. Single rise or ascend SP amplitude caused by mining can reach up to 200 mV, while the increasing amplitude summation, almost 600 mV, is bigger than the decreasing amplitude as long as the water injection is sufficient. As a result, in the later stage of the experiment, SP values were 200 mV higher than those in the beginning. Moreover, SP climbs steeply following the sharp declines. The result of field monitoring of SP during the mine water inrush period is consistent to the indoor experiment conclusion : in the earlier stage of the inrush, a few SP curves fluctuate continuously, with the single rise or ascend amplitude above 200 mV ;while in the later stage all the curves fluctuates a lot and finally got 600 mV higher than those of the beginning. [ABSTRACT FROM AUTHOR]

An investigation was conducted on the characteristics of surface current induced by coal under uniaxial compression. An interpretation of the mechanisms governing the electrical behavior of the coal structures under uniaxial stress tests was presented in this paper. The experimental results show that the current signal is generated during the deformation and fracture process of coal samples. When the load is applied, the electric current makes its initial appearance and increases rapidly after a considerable time lag at 8C, until after the stress reaches a value δc ≈0.75δmax where δmax is the maximum applied stress before sample fracture. There is a good correlativity between the current and the load, and the correlation coefficient between them can reach up to 0.8 to 0.9. The current peaks occur under sudden loading and unloading. It suggests that the current is closely related to the loading. The status of coal loading level may be determined by the current signal. The intensive study on coal surface current can provide a way for monitoring the stability of coal and rock. [ABSTRACT FROM AUTHOR]

Based on the analysis of field observation, drilling data and geophysical data, this paper interpreted the structural deformation characteristics of Lower Yangtze region and its preservation potential for shale gas. The results show that the deformation characteristics of Lower Yangtze region vary in different areas. The structural style is not only different from south to north, but also from east to west. To the east of Maoshan, the structure style is mainly controlled by decollement folding, which was caused by the Indosinian-Yanshan movement. The following extension and reversion movements greatly are destroyed the previous structures. So it still has good shale gas preservation conditions for shale gas and not very hard to explore. The west Maoshan region, however, is strongly reworked by strong reverse and tension movements since the Indosian-Yanshan movement, and as a result a serious of extensional and faulted basins and volcanic basins were formed, which are very negative for the shale gas preservation and explorations. [ABSTRACT FROM AUTHOR]

Currently there is a lack of research on the dissolved gas in gas shale pore water. In this paper, the PVTSim software was used to simulate the solubility of natural gas in the pore water of shale deposit. The results show that the solubility of natural gas in pore water is controlled by the salinity of the pore water, formation temperature and pressure. It decreases with the salinity of pore water, and increases with the burial depth of shale deposit. The dissolved gas can be better preserved in overpressure conditions. A case study was conducted with the Lower Paleozoic gas shale in the Weiyuan area in SW Sichuan Basin. The simulation results show that the solubility of methane in shale pore water is in the range of 3.79-11.34 m³/m³the Lower Paleozoic shale is in the range of 0. 018-0. 054 m³/t. Combined with previous studies, it could be concluded that the amount of the dissolved gas is over 2.2%-8.6% of the free gas,indicating a considerable shale gas reserve. [ABSTRACT FROM AUTHOR]

The characteristics of late tectonic activities were studied in this paper through the field geological investigation in Wuhu area. Combining with the analysis of the regional tectonic evolution, the authors propose that the later tectonic activities which had important influence on the Paleozoic strata are divided into compressive nappe structure at Indo-China period and extensional structure at Yanshan and Himalayan period. Furthermore, the study reveals the tectonic migration regularity and that the shale gas preservation of Paleozoic strata in Wuhu area was less affected by the thrust nappe tectonics of Indo-Chinese movement, while dominated by the extension tectonics of Yanshan and Himalayan movement. This cognition about the influence of late tectonic activities should be considered in the exploration of shale gas. [ABSTRACT FROM AUTHOR]

Taking the Longmaxi Formation in the south of Sichuan Basin as an example, this paper discussed the main factors influencing the pore structures, and studied the characteristics and classification of pore structures using the multivariate regression analysis which was determined by mercury injection method, total organic content (TOC) and mineral composition. The findings are as follows : the mean porosity is 4.71%; the reservoir space is a composite of five types of pores including ultra-large hole, macropore, mesopore, pore and micropore. The pore size less than 1 000 nm is mainly mesopore,pore and micropore, especially in 6-120 nm regions for large composition. Multiple regression analysis shows that TOC and fragile mineral content are in favor of the pore formation, while the clay mineral is opposite. The influence of clay minerals is far less than that of TOC and fragile mineral content, and the TOC is the most significant factor for the shale pore. Based on the mercury withdrawal curve shape and the TOC, pore structure types are divided into three categories: Type I (the convex part in the mercury withdrawal curve and with high TOC), Type III (the concave part in the mercury withdrawal curve and with low TOC), and Type m (the concave part in the mercury withdrawal curve and with moderate TOC). Type I pore structure is in most favor of shale gas reservoir. [ABSTRACT FROM AUTHOR]

Pore characteristics and their controlled factors of some lower Paleozoic shales from the Yangtze area were investigated in this paper using optical microscopy, scanning electron microscopy (SEM) and N2 gas adsorption method. The results show that different pore types are abundant in the samples, including pores in organic matter, solution pores, primary residual pores, iron pyrite inter-granular pores, and micro-fissure caused by clay minerals. The samples have pore specific surface area between 2.99-35.26 m²/g, pore volume between 0. 012-0. 096 cm³/g. The pore volume and pore specific surface area of the samples show some positive relationship with their TOC and clay mineral contents. They are major factors to control pore structures of shales. [ABSTRACT FROM AUTHOR]

The calcination temperature is one of the main operation parameters needed to be regulated during the process of preparing sorbents. The reduction and sulfidation behaviors of 7F3M series mixed metal oxides sorbents with Fe/Mn atomic ratio of 7 : 3 were investigated, and the properties of pore structure and the forms of active components were characterized in this paper. The effects of calcination temperature on the special surface area, pore volume, and the forms and amounts of active component of Fe-Mn mixed oxides sorbent prepared were discussed. In addition, the relation between these effects and the capacities of sorbent removing H2S from hot coal gas was also analyzed under the conditions of different space velocity and sulfidation temperature. The results show that the specific surface area and pore volume of sorbent increase with the increase of calcination temperature, and they reach a maximum value at 600 °C. The sintering phenomenon on the surface of sorbent occurs when the calcination temperature continuously increases, which makes the specific surface area and pore volume of sorbent reduce sharply. The sulfidation temperature has a strong influence on the desulfurization capacity of sorbents through the reduction of sorbent and formation of Fe304 by H2 and CO contained in sulfidation gas. The Fe3 04 in sorbent is the optimal active species for the desulfurization of sorbent in hot coal gas and its amount can be adjusted by the sulfidation temperature and calcination temperature. The 7F3M600 sorbent has the best sulfidation performances at 500 °C and the space velocity of 2 000 h-1. The desulfurization rate of sorbent can reach over 99% and sustain for more than 30 h, in which the sulphur capacity of sorbent is up to 45.56 gS/100 g sorbent. [ABSTRACT FROM AUTHOR]

Considering the variable mass pipe flow of the main and branch boreholes, the CBM pinnate horizontal well productivity prediction model was proposed based on 3D gas-water two-phase flow characteristics in the coal seam. The corresponding calculation program is written based on C++ programming language. At the same time, an actual CBM well is simulated as an example. The simulated results are verified by the monitoring data from the actual site. This paper studies the effects of branch symmetry, the locations of branch points, the angle between main and branch bore-holes, branch length, and branch number on gas production per unit length of the CBM well. The comprehensive results demonstrate the high accuracy of the computation model, and its ability to meet the actual needs of the project. The characteristics of gas production per unit length along the main borehole is high on both ends and low in the middle, with local decline at the branch point locations, while the characteristic of gas production per unit length along the branch borehole is high at heel, low at toe and increases gradually in the middle. Gas production per unit length at branch locations along main borehole declines faster when branches are symmetrical than asymmetrical. As branch node moves from heel to toe along the main borehole, peak gas production per unit length also transforms from toe to heel. The angles of the main and branch boreholes have no effect on gas production. At the same time, gas production per unit length reduces as the branch length along main borehole increases. Gas production per unit length increases with the distance from branch node to heel end. Gas production per unit length increases with the increase of branch length and the angle between main and branch boreholes. However, it declines as the number of branches increase. [ABSTRACT FROM AUTHOR]

In terms of the situation that the adhesive interfaces between new concrete and old concrete or between concrete and other media are mostly under normal stress, the coupling stress-seepage test equipment on concrete adhesive interface has been developed in this study. This paper will present the main functions, technical parameters, equipment system, key technologies and test results. The anti-penetrating test on four groups of the adhesive interfaces between steel plate and concrete was conducted using this newly developed equipment, and the permeability of adhesive interfaces between concrete and different roughness steel plate was obtained. Test results show that the test equipment can provide stable vertical pressure and water pressure needed for the test; and the resistance measurement of infiltration frontal area method proposed is feasible. The impermeability on the interface between concrete and steel plate is good and meets the requirement of waterproof lining. Under the condition of the same axial stress, the permeability coefficient of the adhesive interfaces between steel plate and concrete is related to the roughness of steel surface, more the roughness of steel surface, smaller the permeability coefficient. The equipment has good usability and reliability, and provides a new mean for testing the permeability of the concrete noumenon and adhesive interfaces between new concrete and old concrete or between concrete and other media under stress. [ABSTRACT FROM AUTHOR]

To study water features and hydrodynamic conditions of the No. 15 Taiyuan formation coal reservoir and its roof limestone in the southern Qinshui basin, this paper collected 51 water samples from the river, coal-bed methane well drainage, coal reservoir and its roof limestone in the South Shizhuang region. Measurements of hydrogen and oxygen isotope and main ion concentration in the water samples show that the water discharged from CBM wells is a mixture of coal seam water and roof limestone water. The No. 15 coal seam has a strong hydraulic connection with the roof limestone fracture aquifer, and receives substantial recharge from roof limestone water. The sealing ability of the roof limestone fracture aquifer is weak, and the runoff speed of water in the limestone fracture is fast. Roof limestone water demonstrates a drift of 18O, and the water that is discharged from the CBM wells of the No. 15 coal seam has the drift of both of 18O and D. At the same time, water discharged from the CBM wells of the No. 3 coal seam mainly demonstrates a drift of D. All the water discharged from the CBM wells present a positive correlation with salinity (TDS), and the data of δD and δ18O can be used as reference factors for judging the runoff, conditions of coal seam water. [ABSTRACT FROM AUTHOR]

This paper analysed micropore structure of coal samples from coalmines of Qinshui basin and Huaibei coalfield by using micro-macroscopic observation, Ro testing, and low temperature nitrogen adsorption method. Results indicate that there are five different coal reservoir types in the study areas. High grade metamorphic and relatively strong to strong deformed coal reservoir (type I) and medium grade metamorphic and relatively strong deformed coal reservoir (type III) are favourable for coalbed methane ( CBM) accumulation, but disadvantageous to CBM seepage; high grade metamorphic and relatively weak deformed coal reservoir (type II) and medium grade metamorphic and relatively weak deformed coal reservoir(type IV) are advantageous to CBM accumulation and seepage;low grade metamorphic and strong deformed coal reservoir (type V) is favourable for CBM accumulation, but not advantageous to CBM desorption and seepage. Consequently, southern part of Qinshui basin and south-central of Huaibei coal field are potential areas for coalbed methane exploration and development. [ABSTRACT FROM AUTHOR]

The paper introduced in detail the structure and function of μ225 kV micro-focus CT system with <3 μ m focus size and 0. 5 (xm resolution ratio, and 0. 3% density resolution ratio, which is the most advanced CT system in domestic and provided advanced equipment for micro-mecro structure research of rock. Using this system, pore and crack structure of coal in different temperature were observed, the research results indicate that, during the pyrolysis of anthracite from room temperature to 600 °C, the parameters of pore structure increase at the beginning and then decrease, the structure of pore change most acutely from 100 t to 200 °C, the quantities of the small and big pore all increase, the connectivity of coal goes up;at 500-600%, porosity and specific surface area decrease, connectivity falls; During the pyrolysis of anthracite from room temperature to 600 t, a lot of cracks grow up suddenly and the crack fractal dimension is the largest at 200 °C, during the temperature increasing gradually, the crack fractal dimension decreases gradually and the evolvement of cracks is mainly "extension-anastomosis-connection". [ABSTRACT FROM AUTHOR]

Taking into consideration the differences of disaster prevention in gas and spontaneous combustion of coal seam and goaf cross-scale fracture fields, the cross-scale fractures field of coal and rock mass were defined in this study. In addition, this paper studied the symbiotic disaster prevention and control mechanism, and technical change in cross-scale fractures field flow distribution, through the rational elimination of gas and coal spontaneous combustion symbiotic disaster, that is, the symbiotic region was equal to 0. The authors also proposed two new control technologies, which are: to change coal- rock fractures leakscale through solid-phase media transport, and to change the goaf temperature field and the gas concentration field through low-temperature liquid inert gas seepage. A network graph theoretical model of a particle transport of fine solid phases to change coal-rock fractures scale had been developed in this study, which reveals that solid phase media can be embedded.in the pneumatic transport blocking air leakage in the coal-rock fractureds field, to reduce air leakage fractures scale and the effective fissure numbers, and change the scale of coal-rock fractures leak field, as well as to increase air leakage resistance to ensure the safety of coal spontaneous combustion for high gas extraction. Also, the authors built an experimental simulation platform for investigating liquid nitrogen extinguishing characteristics, and the results show that the liquid nitrogen injected into the fire area can quickly cause heat expansion, resulting in a large number of low-temperature nitrogen pockets in the goaf, forming a three-dimensional buffer zone to reduce the external air leakage into the goaf or fire zone, to isolate the goaf or fire area. At the same time, the low-temperature nitrogen gas carries water vapor condensation into the goaf, exchanging heat with hidden heat source ( fire source), which can reduce the temperature of the heat (fire source) to below the temperature of flammable point and actively engulf the heat source (fire source). [ABSTRACT FROM AUTHOR]

Based on research results of motion parameters of coal-gas flow, this paper analyzes the formation mechanism of shock waves at different states of coal-gas flow in the coal and gas outburst process. While the ejected coal-gas flow has not exceeded the critical state, nor has it reached the state of low under-expansion, both the flow velocity after complete expansion in the roadway, and the overpressure of forming shock wave will be small. While the high or super high degree of under-expanded flow expands in the roadway, the flow will speed up with an explosive process if the roadway space is big enough. Conversely, if the roadway space is limited, the final overpressure of forming shock wave will be smaller, but the dynamic pressure of the two-phase flow and gas static pressure in the expansion process could seriously damage mine production equipment or facilities. The results of these tests are significant to the pre- warning and prevention of outburst disasters, the formulation of contingency plans, and the optimization of mine safety facilities. [ABSTRACT FROM AUTHOR]

This paper presented a new rotor hybrid topologies structure of both the permanent magnet (PM) motors. Surface mounted, built-in and hybrid permanent magnet motor topology model was established using the finite element method to calculate the static magnetic field three structures of the motor. Comparative analysis of their contour distribution of the pole from the amplitude distribution within the air gap flux density in one pole zone was done. EMF distribution in permanent magnet motor with new structure was more close to the sine based on simulation and analysis of EMF. The torque and stator loss without load were calculated. [ABSTRACT FROM AUTHOR]

This paper aimed at the problems such as low restoration rate of land resources and long time for subsidence land reclamation by traditional technology with the condition of final subsided status. Based on the introduction and discussion of the research history for unsteady subsidence land reclamation, the concept of concurrent mining and reclamation (CMR) was proposed. The connotation, principles, technical classifications, and key technologies of CMR for underground coal mining were presented. The advantages with high reclamation percentage of land resources for the new technology were proved based on a case study, which indicated that CMR could increase farmland reclamation percentages to 37. 59% comparing with the farmland reclamation percentage of post-mining. The scope of application and application prospects of the technology were also discussed, CMR could be used in 5 of the 14 large coal bases. It is estimated that the application of CMR could increase land area by 6 680. 8 km². [ABSTRACT FROM AUTHOR]

Based on the summary and analysis of the theories and models which were adequate to interpret the compressibility of saturated clay under low stress, such as diffuse double layer theory and nonparallel plate model, it was found that these theory or model failed to describe the bilinear shape of compression curves under high pressure. In order to facilitate a qualitative description of the complete compression process of clay, the total pore volume was classified into three different structural levels, which were called macropore, micropore and interlayer pore respectively. Under high pressure, apart from the expulsion of the free water enmeshed inside the aggregates and particles, the organized water molecules that adsorbed on the crystals were also be squeezed out layer by layer. And when two surfaces or particles approached closer to a few nanometers, continuum theories of attractive van der Waals and repulsive double-layer forces often failed to describe these interactions; other Non-DLVO forces came into play. Therefore, a new thought of study on the compressibility of saturated clay under high to has been proposed in the last part of this paper. By describing the specific arrangement of water molecules around the clay miner with the lattice density functional theory and conducting steered molecular dynamics simulation, the constitutive relation of saturated clay under high pressure could be constructed on the basis of molecular scale. [ABSTRACT FROM AUTHOR]

The work described in this paper was to determine the improved high-temperature ash-fusion behavior by means of ternary-component blended coal technique. All the experiments based on three kinds individual coal which existed remarkable difference in coal ash chemical composition and ash fusion temperature. According to ternary-component blended coal with a certain proportion, mineral components and ash chemical composition were analyzed by X-ray diffraction( XRD ) and X-ray fluorescence(XRF) separately. The results show that refractory minerals and fluxing minerals in coal have a prominent effect on high-temperature ash-fusion behavior. Mineral Factor(MF) is introduced to characterize this influence between minerals and ash-fusion behavior. Moreover, with the more content of anorthite, the fusion temperature will decrease more obviously, while the law of mullite is just the opposite. Meanwhile, A negative correlation is found between the strongest peak intensity of anorthite as well as the relative content of amorphous glass and the ash flow temperature, quartz and mullite are just on the contrary about FT temperature. High-temperature ash-fusion behavior can be improved by utilizing ternary-component blended coal technique. [ABSTRACT FROM AUTHOR]

To analyze the failure mechanism of shaft lining in thick alluvium and improve its service life, direct reparation for broken' shaft lining, and provide evidence for new shaft lining design, this paper researched the reasons of shaft lining additional stress in Huaibei coalfield, combined numerical simulation and theoretical calculations. The results show that the additional stress is generated by weight of shaft liner and incidental conical soil, which is related to the groundwater depths, soil bulk density, and groundwater layer number. The deeper the groundwater is, the larger the additional stress is. The additional stress in bedrock surface reaches 89. 91 MPa, which is far more than concrete compressive strength. In order to avoid shaft lining breakage, some measures are taken, for example, increasing shaft lining thickness, maintaining original hydraulic pressure, reducing the weight of incidental conical soil and using expansion device in stress concentration area. [ABSTRACT FROM AUTHOR]

This paper studies the characteristics of the breaking process of overburden rocks in shallow coal workface through physical analogous simulation, and obtains the key characteristics of overburden breaking process. Based on the field observation, the study finds the law between roof weighting and overburden fracture development. The results show that the breaking process follows the key points as the breakage of immediate roof, the initial breakage of main roof, the periodic breakage of main roof, the fracture belt's initial connectivity with the surface, and the fracture belt's periodic connectivity with the surface. The internal mechanism of roof pressure existing for long and short periods under shallow buried longwall working face is the fracture belt's connectivity with the surface, and the breakage of the main roof occurs periodically. During the mining process of shallow buried longwall working face, the breakage of main roof easily results in the fracture belt's connectivity with the surface. Therefore, in order to avoid the crushing accident of fully mechanized supports, the working face advancing speed should be accelerated during the period of the pressure change at working face. [ABSTRACT FROM AUTHOR]

To investigate the characteristics of adiabatic oxidation phase and build the prediction model of coal spontaneous combustion critical point, the adiabatic oxidation experiment data of eight coal samples are given in this paper, based on the adiabatic oxidation experiment, element analysis experiment and industrial analysis experiment. The phase heating rates of adiabatic oxidation of these samples are also calculated. Then using the thermodynamic parameter calculation method, Tr0.05 and TΔmax are defined and obtained. Furthermore, based on the Levenberg-Marquardt method, the relationship between the coal element content, volatility, the phase heating rate of adiabatic oxidation and Tr0.05 are established. The results show that the content of N or S correlates positively with Tr0.05 Osand that O, C, or H content correlates negatively with Tr0.05. However, the link between these elements and stage-heating rate is the opposite. The law also suggests that stage-heating rate will be much faster and coal spontaneous combustion will be easier when Tr0.05 becomes much lower. The more volatile coal is, the lower Tr0.05, and the more likely it is to spontaneously combust. [ABSTRACT FROM AUTHOR]

The glauberite soaked under different conditions were scanned by micro CT, focused on the microscopic changes on a fixed lay, and studied the law of glauberite soaked in water affected by temperature and time. This paper combined macroscopic quality changes and microscopic porosity and crack evolution to study the dissolution properties of glauberite under different temperatures. According to the experimental data and theoretical analysis, got conclusion as follows; dissolution of glauberite continues before Na2SO4 reaches its saturation solubility, and two dynamic balance--dissolution and hydration of CaSO4 coexists in the same time. Glauberite porosity is impacted by the speed of dissolution and crystallization. Glauberite easily brakes when dissolved at room temperature, but it is relatively stable at 35, 65 and 95 °C, solution velocity is high within short time, but decreases with time increasing, and solution speed at 95 °C is lower than 65 °C. The ways of glauberite dissolution-penetration are different under different temperature. [ABSTRACT FROM AUTHOR]

On the basis of discrete element method, this paper built the particle flow model of coal particles through slotted screen with PFC2D software, presented the ability of coal micro-particles through slotted screen, as well as the influence of parameters, including joint strength between particles, slot width divided by particle diameter and ambient pressure. The results show that the passed particle linearly decreases with the joint strength increasing. As the ratio of slot width divided by particle diameter going up, the passed particles increase correspondingly. And to ensure coal-bed structure stable, the ratio should be less than 10. Besides, the volume increases with ambient pressure rising, yet there is certain jumped platforms, which means the volume will be stable in some depth ranges. [ABSTRACT FROM AUTHOR]

In order to solve the challenge of the deep roadway construction, through comparatively analyzing the existing roadway excavation, support methods, and TBM technology, it shows that TBM has obvious advantages, and meets the needs of the roadway construction deeper than 1 000 m; modern large-scale mine is also capable of introducing TBM; the authors intends to introduce TBM to roadway construction deeper than 1 000 km, which will be improved later on the basis of the involved key rock mechanics and machinery manufacturing problems having been solved, called Full Face Roadway Boring Machine (RBM). Due to the significantly difference of the construction environment between the deep coal mine roadway and tunnel, RBM construction will face two key issues: shield jamming and the rock fragmentation. In order to reveal RBM shield jamming mechanism, this paper points out the key rock mechanics problems, including; roadway deeper than 1 000 km surrounding rock masses squeezing deformation mechanism under RBM excavation unloading paths; squeezing deformation distribution law of the rock masses around the shield; the interaction mechanism between ground, shield and support; shield jamming criterion; control theory and method for shield jamming. [ABSTRACT FROM AUTHOR]

This paper probed into the whole height bench cast blasting process and described the influence factors from 3 major perspectives; natural geological, blasting scheming and factitious ones, and selected the throwing rate which was generally accepted in the cast blasting field to assess the blasting performance. Then a novel GA-SVM model was constructed to analyze the real collected explosion data from open pit mining, and verified in a certain open-pit. Also the MIV method was employed to analyze the influence factor at each input factor. The study indicate that; (T) the presented GA-SVM model performs more robust and accurate than other artificial intelligence models such as BP, RBF, GRNN and GA-BP, which has a more stable prediction accuracy of 83.75%. Moreover, due to the ubiquitous paradigm of the presented approach, it provides a single, unified approach to evaluating other blasting performance factors such as the longest thrown distance and loose coefficient etc; (2) for this certain open pit which maintains a steady lithological character and design parameters, the bench height, explosive specific charge possess a positive correlation coefficient with the throwing rate, while line of least resistance, the slope angle and the profile width perform the opposite. [ABSTRACT FROM AUTHOR]

Based on the mechanical model of the coal-wall in extraction opening under high bearing pressure, this paper analyzed the basic distribution of the stress on the interfaces between the coal and rock and the axial force of coal. It first mechanically derivated the total horizontal displacement of the coal and established a new theoretical width formulas about the limit equilibrium zone in sidewalls. On this basis, discussed the main factors of the width without failure zone. The analysis results show that the stress and level pressure of the coal in the limit equilibrium zone distributes at the pattern of hyperbolic function. The vertical stress of the sidewall coal changes by the roadway height and mechanical parameters on the interfaces between the coal and rock. The horizontal displacement increases with the lateral pressure coefficient and peak stress of the elastic-plastic interface and the width of the limit equilibrium zone, while inversely proportional to the average elastic modulus of the coal. The width of the limit equilibrium zone depends on the external factors such as extraction opening depth, the average density of the overburden, the strength parameters of the interfaces between the coal and rock, stress concentration factor, lateral pressure coefficient, extraction opening height as well as composite elastic modulus of the coal. It increases with the addition of the extraction opening depth and extraction opening height and decreases with the addition of the internal friction angle and cohesion interfaces between the coal and rock. Finally, the rationality of these results were verified by an engineering example. [ABSTRACT FROM AUTHOR]

In order to study the force variation of the drill bit in the dynamic process of rock drilling deeply, systematical dynamics analysis was presented in the paper. Differential equations which described the force fluctuations in the process of rock drilling were established and various factors which affect the force fluctuations of the drill bit were also analyzed. Based on the analysis of the process of movement in rock drilling, analytical method for force computation of the drill bit in the dynamic process was given. Analytical calculation model of penetrating force and cutting force in the dynamic process was derived respectively. Studies show that the force of drill bit is closely related to its motion state; the average penetrating force and cutting force in the dynamic process increase with the increasing of penetration speed V in the case of the other conditions remain unchanged. Calculation results show that the analytical dynamic model is more precise than the traditional method of static calculation model compared with experimental measurements, and more conducive to be a intuitive and laconic guidance in engineering practice. [ABSTRACT FROM AUTHOR]

On the basis of actual producing data, combined with the fluid inclusion studies, this paper analyzed the characteristics of water yield and its influence factors during CBM production in Liulin area from the paleo and present hydrogeology, production model and fracturing technology. The results show that the water yield in Liulin area comes from the common action of many factors. The coal seam roof sandstone aquifer of Shanxi Formation,in which the paleo-fluid presents detained feature, has relatively weak water yield property and its present water yield has a direct relationship with the distribution of fracture. The coal seam roof limestone aquifer of Taiyuan Formation has a communication with surface fresh water in the early stages,which has relatively strong water yield property. During the production by different model, under the influence of fracturing strength and the differential communication of coal seam with roof aquifer,the water yield shows gradual increasing by the order of model D,A,B,and C. We further point out that in order to depress influence of hydrogeology,some horizontal wells can be selected in proper area,the production of CBM can be carried out from northeast to southwest which is favorable for drainage and pressure lowering of coal seam, and fracture size can be decreased, especially the height of vertical fractures. [ABSTRACT FROM AUTHOR]

Taking Pingdingshan mining area as engineering background, the paper analyzed the terrain curvature of Pingdingshan mine area and the distribution characteristics of curvature radius according to DEM model, and then discussed the influence of terrain curvature on the coal and gas outburst. The relation model between the numbers of coal and gas outburst disaster and curvature radius was established. The results show that coal and gas outburst occur mainly in areas with the curvature of bigger change and positive radius. There are little coal and gas outburst in the negative curvature radius areas. [ABSTRACT FROM AUTHOR]

In order to study the law of gas desorption and emission, a desorption experiment of coal particles in different sizes under different initial pressures was designed. And the measured curves of gas desorption accumulated amount with the change of time were obtained. According to Darcy law, the paper also built the mathematical model of gas emission which was disposed with finite difference method. The visual Basic language was used to solve and calculate the mathematical model. The variation regulation of gas pressure in the inter coal particle and the accumulative desorption quantity at different pressure are finally obtained. Through comparing the simulation results and experiment results, the conclusion shows that the gas emission from the coal particles corresponds to Darcy law. [ABSTRACT FROM AUTHOR]

According to the breakage and fracture developing of overlying strata, the layer with fracture diameter of more than 10-1 mm is the mining gas channels development area. Based on the theory of voussoir beam structure, the characteristic of gas channel development in the overburden under the key stratum was studied, and the identification method of the gas pattern were established for gas flow in gas channel based on Kozeny-Carman criterion. Then the overlying rock was divided into turbulent channel area, transitional circulation channel area and seepage channel area, according to the gas pattern in gas channels, and the artificial diversion method for transitional circulation channel area was set up by taking high level suction roadway as main means. Finally, the evolution law of gas channel and its influence on gas guidance flow was inversed by field test at working face 80201 in Xinjing Coal Mine of Yangquan Coal Industry (Group) Co., Ltd., and the gas pattern was classified for transitional circulation channel area,which verified the correction and rationality of the theoretical method and the classification for mining gas channel proposed in this paper. [ABSTRACT FROM AUTHOR]

Aiming at travel time prediction problem in optimal dispatching of truck in open coal mines, a truck travel time prediction model which considered various truck travel time influencing factors was built. Using least squares support vector regression(LS-SVR) algorithm and selectivity ensemble learning concept, this paper proposed a truck travel time dynamic prediction method realized by selectivity ensemble learning algorithm based on least squares support vector regression. Experiments were done using the practical data acquired from open coal mines. Higher prediction accuracy was obtained, and the effectiveness of the proposed algorithm was proved. [ABSTRACT FROM AUTHOR]

On the basis of a brief overview of mining with backfilling history and the objectives, requirements and difficulties of developing modern mining with backfilling technology, this paper systematically introduced the research progress of fully mechanized mining with solid backfilling technology, focused on the expounding the strata movement theory of mining with dense backfilling, including equivalent mining height theory of strata movement control, continuous media mechanics model of strata movement, calculation formula of strata movement, and stope rock pressure and support stress analysis, which are the prerequisites of the new technology. And then detailedly introduced the system, equipments and technics of fully mechanized mining with solid backfilling technology, and the engineering examples of large-scale mining with backfilling under dense buildings, island village coal pillar, near the loosen aquifer and under the large embankment. [ABSTRACT FROM AUTHOR]

Aiming to research the process of air flow remote control technology and best air distribution during disaster relief, by using mine ventilation, fluid dynamics and combustion theory, this paper analyzed the influence on air quantity regulation of fire spread speed, smoke back flow, and the phenomenon of leapfrog during fire disaster relief process. Combined with actual situation, analyzed the change of ventilation network before and after fire disaster relief, calculated fire area wind resistance and regulation wind resistance of air doors under four kinds of different openings. Based on ventilation network calculation technology, the best air distribution and fan operating conditions were obtained during disaster relief process. Remote air quantity regulation and control method were put forward, air quantity of smoke and non-smoke area monitored and real-time display, and adjustable opening of air doors structure and remote control program were designed. [ABSTRACT FROM AUTHOR]

Aiming at the question of deep mine tunnel surrounding rock deformation's prediction, a new prediction model which was based on fuzzy mathematics theory and gray theory was established. Firstly, this paper fuzzed monitoring data sample by using fuzzy mathematics theory, adopted historical data of different periods to endow different degrees of membership, and weight parameter was led in the factors influencing deformation of surrounding rock of tunnel, inverted the measured data sequence to a fuzzy data sequence accompanied with weight parameter, then used gray theory to establish a Fuzzy-Gray-Model. At the same time, it has the function of metabolism and developed Fuzzy-Gray-Model prediction system on the platform of Matlab used to predict surrounding rock deformation, and got the success of the engineering application. [ABSTRACT FROM AUTHOR]

Aiming at the current status of coal mining problems in China, this paper put forward the concept and connotation of "scientific coal mining" and "sustainable capacity of coal mining". Scientific coal mining is to maximally obtain natural resources on the premise of the harmonized geology and ecological environment under the guidance of outlook of scientific development, and to achieve sustainable mining with safety, high efficiency, green, economy and social harmony on the premise that hazards posed by complicated geological conditions and engineering circumstances were controlled; sustainable capacity of coal mining refers to the maximal coal mining capacity using safe, high-efficient and environment-friendly method on the premise that the reserves for sustainable mining within certain period were guaranteed, mainly including three requirements; safe mining, green mining and high-efficient mining. Accordingly, innovatively proposed the assessment index system and standards of the sustainable capacity of coal mining which are comprised of mining safety level, green level and mechanization level and makes comparative analysis of the current sustainable capacities of coal mining of the five coal production areas in China, the whole China and the advanced coal mining countries in the world. The results show that the coal mining capacity in 2010 scores 42.58 on average, and the coal output which complies with the standards of the sustainable capacity of coal mining and scores over 70 is about 1.078 billion tons, accounting for only 33.27% of the overall coal output; while the sustainable capacities of coal mining of the advanced coal mining countries like the United States of America, Australia, Britain and Germany score over 90. There is still a big gap between the coal mining in China and that in the advanced coal mining countries in the world, so China should extensively disseminate the idea of scientific coal mining and sustainable capacity of coal mining, insist on scientific coal mining, and raise the scientific level of coal mining in an all-round manner. [ABSTRACT FROM AUTHOR]

According to the dynamic and complex characteristics of the mine ventilation system, the algorithm of choosing the optimum circuit for the minimum regulation number of measuring airflow and evaluating resistance model was put forward. Combining with the real-time dynamic monitoring data of the air volume, the paper established the measuring airflow & evaluating resistance model of the mine ventilation network based on the monitoring data. Because it easily constructed the ill-posed coefficient matrix while the model applied to the complex network, the solving method of parameters of the Tikhonov regularization based on the greedy algorithm was proposed to revise the model. The application shows that this method can reduce the severity of ill-posed matrix and moderately solve the resistance of the complex ventilation network. It exerts the real-time dynamic monitoring function of the monitoring system and provides the basic data to the dynamic simulation of mine ventilation system. [ABSTRACT FROM AUTHOR]

Employing a lot of lab tests, this paper investigated the impact of salt solution on the expansibility, the roller recovery rate and the permeability of coal rock samples collected from No. 3 coal seam in Jincheng. The impact of salt solution on drill pipe's corrosivity was also investigated. Here salt solution includes various types of salt such as NaC1, KCl, CaCl2, HCOONa and HCOOK with the concentration varies as 5%, 10% and 20%. The results show that: firstly, fresh water can bring formation damage to gas bearing coal seam when it is used as drilling fluid in coal seams with a high content of clay minerals; furthermore, in presence of salt solution, adsorption and swelling of coal rock matrix can be restrained and even the matrix can shrink, increase of weight percent results in better inhibitive performance when same type of salt is used; finally, with the integrative consideration on technology feasibility and economic cost, HCOONa and HCOOK have better inhibitive performances and lower corrosivity compared with other salts and the optimal concentration are 10%. [ABSTRACT FROM AUTHOR]

Based on the mine ventilation network calculation in this paper, all the mine ventilation system ambient temperature was real-time calculated and analyzed. First, different heat sources that effect the airflow temperature were classified and the basic calculation formula of heat sources was determined; second, according to compartmentalization of various types of roadway, different quality of the roadways was analyzed ; finally, combined with the actual conditions of coal mines, ventilation system airflow and temperature parameters were calculated. These achievements can provide theoretical basis and reference value not only for the system's exploitation, reconstruction and development, but also for the design of ventilation system. [ABSTRACT FROM AUTHOR]

Based on the Kaiping coalfield gas geology research, using the method of hierarchical tectonic control theory, this paper systematically researched control action of different levels of tectonic activity on gas occurrence of kaiping coalfield. The results show that except coals with once coal generation process in NW part of Kaiping syncline, coals go through twice coal generation processes in other parts, because of the influences of thrust nappe structure and magmatic intrusion. Tectonic development inhomogeneity of Kaiping leads to coal the difference of gas occurrence. Due to the sealing role of reverse faults and water, there are good gas storage conditions in NW part, while gas loses too much in SE part because of the dissipation role of normal faults and water. Different tectonic evolution and tectonic types have different effects on coal heterogeneity. With different coal metamorphic grade and deformation characteristics in the local, there are different pore-fracture features, which leads to different gas-bearing properties. [ABSTRACT FROM AUTHOR]

Based on depth study of the influence law of key strata on the height of fractured water-conducting zone, this paper proposed a new method to predict the height of fractured water-conducting zone by location of key strata. The engineering measurements and theoretical research results show that the key stratum location affects the height of fractured water-conducting zone in the roof, when the distance from key stratum to the coal seam is less than a critical value, the fracture of key stratum will develop to water-conducting fracture, and the same goes to the fracture of the overlying strata controlled by key stratum leading to a synchronous breakage with key stratum. The critical height of key stratum fracture can be roughly estimated to be (7 ~ 10) M, where M is coal mining height. When it is less than (7 ~ 10) M from the primary key stratum to coal seam, water-conducting fracture will grow to the location above the roof of the bed rock, then the height of fractured water-conducting zone is equal to or greater than the height of the bed rock. When the distance from the primary key stratum to coal seam is greater than (7 ~10) M, water-conducting fracture in the roof will develop to the position below the nearest key stratum being (7 ~ 10) M more away from the coal seam ,and then the height of fractured water-conducting zone equals to the distance of the key stratum to coal seam. The prediction method is able to predict the height of fractured water-conducting zone in the roof with different mining heights, meanwhile, it also can be utilized to distinguish the abnormal development of the height of fractured water-conducting zone induced by structural changes of key stratum, and its reliability is verified by engineering measurements results. [ABSTRACT FROM AUTHOR]

In order to effectively control rock burst disaster due to the process of corner coal pillar recovery, it is available to use the theoretical analysis and numerical simulation to analyze the overburden structural characteristics and induced mechanism and control measures depending on characteristics of isolated coal pillar with trilateral gob. It shows that isolated corner coal pillar working face with trilateral gob has anti-arc overlying rock structure composed of "T" and "Γ" structure, which can make the coal pillar form an anti-arc high stress and elastic energy accumulation district around the working face; the main reason which induced rock burst is that the cyclical movement of "Γ" structure leads to the anti-arc overlying rock structure being in the dynamic process and the comprehensive role of the static and dynamic stress affect the steady state of the coal body in the process of recovery. This paper puts forward the non-symmetric control countermeasures weakening the implementation of relief along the coal side of roadway and strengthening support to narrow coal pillar side, to reduce the impact of anti-arc structure of overlying strata and control the impact of risk. [ABSTRACT FROM AUTHOR]

Through the industry linkage analysis of coal and related industries, three basic types of coal industry chain were brought forward. Gave the evaluation method of the industry chain efficiency based on date envelopment analysis (DEA), evaluated the operating efficiency of coal industry chain of 19 regions in China. It turns out that different provinces are different in the coal industry chain efficiency, and the eastern provinces are higher than the middle and western regions. Finally, this paper explored the development strategy of coal industry chain. [ABSTRACT FROM AUTHOR]

Microscopic mechanism of adsorption heat's generation was expounded systematically. On the basis of the potential energy model, two-energy-state model was got and the computational formula of the corresponding adsorption heat was deduced. On the basis of the grand canonical ensemble theory, the Langmuir monolayer model of statistical mechanics was got, and the computational formula of the corresponding adsorption heat was deduced. This paper cited De Broglie thermal average wavelength, and got the approximate computational formula of adsorption heat based on the Langmuir monolayer model. To compare the two models, it shows that adsorption heat is much affected by the adsorption capacity, adsorption centers and the average distance between molecules, and that we should use different physical models for analysis towards the outer layer of methane (relative to the coal surface) and the inner methane. On the basis of the Langmuir monolayer model, from perspective of adsorption, the fractal features of pore structure and fracture structure was studied, the two-dimensional fiat surface adsorption to the fractal surface adsorption was extended, and a fractal dimension based on De Broglie thermal average wavelength was got. [ABSTRACT FROM AUTHOR]

To reflect the effect of confining pressure on the brittleness of the post-peak rock, the degradation angle of post-peak strength of the new parameter was presented. Based on the test data for mudstone of Shanxi in triaxial compression, the linear relationship between the degradation angle and the confining stress was founded. The law between the equivalent plastic shear strain and the degradation angle was presented, and the strain softening model of rock based on the degradation angle was set up. Fish function method within FLAC was used and the numerical code was developed. In numerical case study, the strain softening processes under variable confining pressure for mudstone of Shanxi were modeled. The simulating results accord with experimental data. Those show that the degradation angle is an effective parameter to reflect the effect of confining pressure on the brittleness of the post-peak rock; the model in this paper is reasonable and can be used to model the strain softening processes of post-peak strength rock. [ABSTRACT FROM AUTHOR]