Top-coal caving face always suffered abnormal roof weighting under the condition of ultra-thick alluvium and thin bedrock, which is a great challenge for roof control. Numerical calculation was employed to analyze the roof failures under the different condition with 600-m-thick alluvium and different bedrock thicknesses. The results show that all the overburden may shear off if the bedrock thickness is less than 120 m; the thick alluvium is a whole structure in deformation but difficult to form a stable bearing structure. The filed investigation presented the abnormal roof weighting and proved the relation between the thick alluvium and the thin bedrock. The achieves provide a reference for mining safety under similar conditions.

According to 845 workface in Datai of Muchengjian coal mine, this paper makes the similar simulation test of backfill mining in steep coal seam by gangue using polyethylene plastic foam board as backfill and taking the backfilling while mining in steep coal seam. It research on the overburden migration rule in the process of backfill mining in steep coal seam. It indicates that: rock stratum above the gob have two-zones (caving zone and fissure zone) in the process of backfill mining in steep coal seam, the caving of roof is not easy, eventually it forms the trapezoidal caving arch which is tilted and asymmetric; The blocks of polyethylene plastic foam can simulate the stacking of the loose gangue to support and yield for surrounding rock; The style of backfilling while mining can grasp the filling time to control the crack propagation and stress concentration of the roof and floor to avoid the burst of surrounding rock and given the test evidence to backfill mining in coal mine, it has perfected the mining method of the steep coal seam.

Abstract: According to the principle of inclinometer and the special movement law of overburden rock under mining, the paper analyzed the limitation of conventional inclinometer applied to monitoring level displacement deformation in mining engineering. Based on conventional inclinometer, a new type of monitoring instrument- none wheel probe inclinometer was invented, which solves the problem of probe getting jammed in the hole when monitoring. Take the settlement hole around 7267 working face in Yaoqiao Coal Mine, for instance. Through analysis of the data measured by none-wheel probe inclinometer in different hole, the result shows the data is stable and could well reflect the variation law of formation; through T-test and fitting analysis of a same hole data, the result shows there is no significant difference between the data and change trend of two horizontal displacement curves is in welded joints, which ensures the reliability of the data in deep formation. The results showed that double-probe inclinometer could adapt to the condition of overburden rock, moving obviously and being deep, the data measured by which being accurate and reflecting the variation feature of formation in unconsolidated layers combing with the related geological data.

Based on the instable mechanism of fully mechanized caving face with large cutting height bracket - rock system of special thick coal seam in Tongxin coal, the author explores the elements which impact the stability of fully mechanized caving face, meanwhile establishes the instable fault tree. Using triangular fuzzy function and Boolean algebra method, the author calculates the probability of the occurrence of the top event and evaluates the security of the system. The author also ranks the importance by calculating the fuzzy importance of the basic events, and thus ascertains the main elements causing the fault of fully mechanized caving face with large cutting height bracket - rock system.

n order to study Si he Mine 2nd Temple wells IX4302 island face “two hard” rock (hard roof and hard bottom) under geological conditions Strata Behaviors for the safe and efficient mining face similar reference. Firstly, similar to the simulation results overlying strata movement and Strata Behaviors and guides used in engineering practice, and through on-site mine pressure line monitoring and roadway deformation observed, studied law and periodic pressure face abutment pressure range, both complement each other confirmed. The results show that, due to the small mining height face, by the "two hard" rock island in the form of greater impact, periodic weighting obvious, but not strong, basic roof first weighting step distance of 45.7m, periodic weighting from an average of 16.4m; abutment pressure in front of 11m at the coal wall, roadway deformation.

Abstract: Under the condition of fully mechanized tunneling driving, abilities of driving and platoon lane don't match is an important factor of restricting the speed of rock driving. Through the analysis of China's rock roadway tunneling current situation of platoon lane system, based on the continuity and reliability of platoon lane system, platoon lane system will be divided into rigid platoon lane system and flexible platoon lane system，points out additional temporary storage bin of platoon lane system help to further improve the speed of driving, at the same time, focuses on the analysis of factors affecting the flexible platoon lane system in view of the influence factors puts forward the corresponding reform strategies. After application of reformed platoon lane system in Pingdingshan No.11 coal mine bed plate tunnel of 24011 working face, the amount of month driving up to 312m,shows that the flexible platoon lane system has promoting significance.

Aiming to larger prediction error of discharge and mine water bursting cannot be managed due to mine drainage ability, the paper studyed the main factors affecting mine discharge based on the secular dynamic variation rule of mine discharge in Longgu mine. First, revealed variation of water-filling factor of mining effects on prediction of discharge. The numerical method was used to predict the dynamic variation of mine discharge in the mine excavation process with mine development progress. The results showed that compared with the previous simulation method that scope were unchanged, if considering the excavation sequence and real-time adjusting pumping wells for simulating discharge, taking the simulating results that coal extraction in advance as initial flow field of later model, the prediction of discharge would be more accurate, the calculation error was reduced to some extent. It had more spreading values by above method.

Abstract: According to the physical and chemical properties of fly ash and its active principle excited to iron ore tailings as aggregate, fly ash and ordinary portland cement clinker cementitious materials to uniaxial compressive strength for different ages indicators, research tailings backfill way to stimulate activity in the fly ash, to determine the physical and chemical inspire inspire inspire ways of combining complex. Complex ways to stimulate and inspire experimental verification of the physical and chemical excited about the combination could increase the intensity of 40%. Clearly the best way to stimulate the composite ash grinding 20 minutes, mixed with activator ratio of calcined gypsum 2: Na2SO4 0.1: CaCl2 0.2: Na2CO3 0.2.

In order to solve the problem that schemes of preventing over-grade trip can not satisfy the requirement of speed, this paper proposes a scheme of preventing over-grade trip based on switched Ethernet. This paper analyzes the working principle of the protection system, designed an intelligent interlock device. The selectivity of the protection is achieved by sending and receiving interlock signal setting different blocking time of protection at various levels. Finally, the Ethernet is simulated to validate its stability, reliability and real-time performance. The scheme can effectively prevent the occurrence of over-grade trip, to ensure the safe operation of coal mine power supply system.

The resonant grounding system will go through a transient state when phase to earth fault occurs in Coal mine 6kV network, and the zero-sequence current of all the lines will generate a transient pulse in this period. In order to analyze the relationships between the initial amplitude, duration of the transient pulse and the earthing resistance, the earth capacity, and fault time, the paper deduces zero-sequence current expressions when phase to earth fault occurs in single substation mode and multi-substation mode. Meanwhile, related expressions are also given. It is found that the transient pulse polarities between the fault lines and normal lines are completely opposite, and the transient pulse’s amplitude of fault line is the largest among all the lines. Moreover, the amplitude of transient pulse is proportional to the sin of fault angle and inversely proportional to earthing resistance. Besides, all the normal lines have the same width of transient pulse, which is smaller than that of fault line, and which is proportional to earthing resistance. Last, the simulation by matlab proves the correctness of these conclusions.

To investigate the deashing effect of emulsified diesel oil to Wuhai fat coal, the emulsified diesel oil and diesel oil were employed as collector to do the lab flotation experiments, and the combustible material recovery and flotation perfectness were used as evaluation index. The results showed that the emulsified diesel oil had a better selectivity, at the case of same combustible material recovery, the ash content was lower using emulsified diesel oil as collector than using diesel oil, and the best collector dosage 0.8kg/t was determined, which can save 73% oil. The classification flotation was adopted to investigate the deashing effect of different size fraction coal sample. The mechanism of deashing of emulsified diesel oil was discussed through the contrast the hydrophobicity and Zeta potential of coal sample before and after agent acted.

Coal slurry pipeline pressure distribution is related to many factors, and presents the complex nonlinear relationship. The pressure lossmechanism and influence factors of coal slurry pipeline are analyzed in this paper.Considering the coal slurry pipeline pressure loss is combined action of shear stress and frictional resistance, the pressure distribution modelsof the horizontal straight pipe, inclined pipe and vertical pipeline are built respectively.Test results show that the model can accurately calculate the stress distribution of coal slurry pipeline.

The laser induced breakdown spectroscopy (LIBS) has been used to detected the concentration of ash in coal. Applied the partial least squares (PLS) method on 10 selected samples which are known as the calibration samples to establish quantitative analysis regression on models of the whole ash content. Then, use 3 untested samples to test the result of quantitative analysis regression models. The result shows that the laser induced breakdown spectroscopy combined with partial least squares method can detect the concentration of ash content in coal. The average relative errors (REP) are less than 8% mass fraction. The experiment verifies the applicability of the laser induced breakdown spectroscopy in synchronization measurement of ash content in coal.

This paper introduced the working principle and material properties of floating oil seal, took a floating oil seal in high torque hub reductor installed a heavy duty truck as research object, described a successful example of the floating oil seal in the application of coal underground mining equipments. But for its common failures, oil leakage and high temperature, were examined and analyzed. At last, especially describe a right installation method for floating oil seal.

The horizontal vibrating centrifuge common fault and its treatment method. In the full import solutions of horizontal vibrating centrifuge structure and working principle, the sealing device and the feeding system structure is improved and achieved good results, improve the reliability and stability of the whole machine, is in large scale, the localization of the horizontal vibrating centrifuge has laid a solid foundation.

This Paper introduces the working principle, structure and the control strategy of single machine control system of the domestic first binderless high-pressure roller briquetting machine used for lignite upgrading. At the same time, according to the needs of the production of remote real-time monitoring and controlling several roller machine, combined with the technical advantage of PLC and DCS, using DP communication mode to achieve real-time monitoring and controlling several roller machines. This way is proved to improve the safety and reliability of the system.

Since the 90's of the last century, Donghuantuo Coal Mine auxiliary shaft headframe has subsided more than 100mm. The subsidence has affectted the safe of the hoisting system. After two times of attempt to adjust, the problem remains.By analysis the data of deformation observation, situation of coal mining surrounding the industrial square, the changes of the underground water level, and the load of the auxiliary shaft headframe, the writer demonstrates the main reason of the subsidence is the land subsidence caused by the decline of the Quaternary Groundwater level year by year, which is caused by drainage of groundwater and the water pumping by wells in the Industrial square areas. At the end of this paper, the writer give a plan for prevention measures of the subsidence of Donghuantuo Coal Mine auxiliary shaft headframe.

Metal minewaste tailing dumps are a typical degenerated ecosystem. By studying the ecological problems confronted during the procedure of restoration of them, the use of ecological restoration of abandoned mining area of soil improvement and pioneer species selection method for the reclamation of tailing dam waitoushan analysis shows that mineral waste to restore the ecosystem and regional social development are closely linked to ecological - economic projects.

For the correct guidance of economic security support of deep mine crossheading, the paper studied the crossheading deformation failure mechanism and law influenced by supporting and dynamic mining pressure by FLAC3D numerical simulation software. The results showed that roadway deformation and deformation rate significantly increased with more than 1000 mm of roadway deformation, and the closer distance from working face, the faster the change trend, amounts of closer than 1000 mm influenced by dynamic mining pressure. In 40 m from the working face, the deformation rate comparatively decreased affected by periodic weighting, and the deformation rate of roadway sides and roof –floor is the largest in 10 m from the mining working face to monitoring point.

Based on the B10 coal seam occurrence conditions in Shajihai mine, the technical feasibility of the high cut in fully mechanized coal mining and full-mechanized caving mining were analyzed. The coal bed pitch, hardness, burial depth and spontaneous combustion were the main influencing factors for the mining method selection. The mining methods of high cut in fully mechanized coal mining and full-mechanized caving mining were feasible for B10 coal seam through adopting some technical measures. The both methods had some advantages and disadvantages. The method of high cut in fully mechanized coal mining had a high degree of automation, less personnel and equipment, manageability, higher recovery rate and lower gangue content. The method of high cut in fully mechanized coal mining were confirmed for B10 coal seam.

The docking device of bottom and orifice has been designed under the real background of XueVillage ore. According to the field test, when fully meet the safe-haven needs, the drilling docking device can not only enhance the economic and flexibility of hedging facilities, to some extent, it can also improve the level of the emergency system of the permanent drilling-type refuge chamber.

By comparing the relevant provisions of rock-socketed pile bearing capacity calculation in the standards and regulations of different industries and different regions, and starting with the main factors influencing the bearing capacity of rock-socketed pile, the paper analyses the similarities and differences among all kinds of specification methods, pointing out the shortcomings of the current specifications, and puts forward the author’s suggest for rock-socketed pile bearing capacity calculation .

The bearing capacity and fireproof limit of SRC column will sharply descend considering the crack of outside concrete , so this optimal design method is based on fail-safe seismic design. By preassigning and pre-reinforced the position of outside concrete that will easily crack ,the optimal design method can guarantee the global stability of the structure and the personnel safety inside. Then verifying the method by theoretical derivation and large finite element analysis software ANSYS. The results indicate that preassigning and pre-reinforced the position of outside concrete do increase the stiffness and fireproof limit of the column , consequently ,increasing the security under the emergency of fire.

In the process of shaft belonged to PiLiQing coal throughing the soil layer adopted the ordinary method , the formation revealed is loosed thick loess, poor stability, in order to ensure the safety of construction of this section, in combination with the construction operation, economic and other aspects, through research, experiment and field, for the first time using T-steel inserted into the construction scheme of loess, hang tight hole, and to validate the actual effect of construction the technical scheme, provides feasible construction of to through the thick loess by the ordinary method.

The study carried out the physical and mechanical properties test of frozen rock in the area of east and northwest, and compared the differences between difference area, then the physical properties of rock in Cretaceous and Jurassic strata such as the big thermal conductivity coefficient, the small specific heat and the small frost heaving and so on have been obtained. Rock is high in strength, under the condition of low temperature, with the decrease of the maintenance temperature, the strength is further improved, but mainly in -5~-10℃, in -10℃, the strength is more than 10MPa, the limit fracture strain is in 1%~3%. The freezing method in deep alluvium in east has been discussed, based on this experience, the freezing method in Cretaceous and Jurassic strata mainly considers waterproof and the influence of blasting on freezing tube when driving, so it should be appropriately increased the diameter of freezing pipe, but with the single coil tube can meet the engineering requirements. The results can provide a reference for the design of freezing in Northwest China.

This article through to monitor the temperature of freezing shaft wall between learned about shaft wall in the set of a wall within 20 days after the end of the shaft wall is still positive temperature, and according to the borehole wall concrete strength increasing grouting pressure calculation between the wall, to ensure that the wall between the grouting effect, improve the wall between the compactness, think at the end of the set of wall to wall between grouting time is the best.

The surrounding rock controlling technology of the gob-side entry driving with high stress in the island coal face is one of the necessitated problems in coal mines. Take the return airway No.80509 of the No.2 Yangquan colliery as an example, combined with field observation, experimental test, theoretical analysis and field test, etc., the deformation and broken process of the roadway, the X-ray diffraction and electron microscope scanning to the immediate roof, floor of the roadway and the mining coal seam, physical and mechanical properties test to the coal and rock samples of the immediate roof and floor are studied, respectively, and then a combined support technology including high performance bolt, pre-stress cable and pre-stress cable truss is put forward. We obtained: (1) The deformation and broken process of the gob-side entry driving with high stress in the island coal face is: lower part “leaving the former place” of the coal side, the upper part “loose coal side”, “move the coal side” and “collapse of the roadway”. (2) The deformation origin are large disparity of the physical and mechanical properties of the immediate roof and floor, high lateral stress and mining stress and the improper support technology. (3) The new type of supporting technology could effectively control the deformation of the surrounding rock of the roadway and safeguard the roadway safety during the excavation and mining activities. The obtained research has some preferable value to supporting design to similar coal roadways.

Inclusive development is a development thinking focused on the comprehensive human department, emphasizing equal opportunities and shared result. Based on the inclusive development thinking and combining with the characteristics of large-scale coal resources, the paper has set 32 evaluation indicators from five inclusive perspectives, including the project and comprehensive development of people, project and resources, project and environment, project and economic development and project and society, to build the multi-dimensional evaluation index of large-scale coal resource development project.

According to the coal mine environment caused by the bad gas sensor error alarm, namely gas "large" problem, this paper presents the configuration monitoring software and the application of BP neural network in coal mine gas monitoring system, configuration monitoring software can be used to real-time observation of gas concentration, query any time the output of the sensor, according to gas concentration change, through the design of BP neural network and training for many times, and correct network parameters, finally the reasonable neural network, and testing the network, the network effectively eliminate the pulse interference phenomenon of false alarm caused by gas concentration and prevent gas leakage alarm when concentration overrun. In the coal mine safety monitoring system, the application of neural network to remove false alarm has good prospects for development.

A new method of Open-pit Topography and Geology Integrated Solid Models dynamic update was put forward based on surface mining character. In this method, the topography and open pit field models local update in extended boundaries was realized by seamless splicing between New Tins and Old Tins. And the geology solid model was composed of stratum and geologic bodies’ models, which were reconstructed by re-interpolated Points based on new adding reality points. After that Open-pit integrated solid model updated was come true by Boolean coupled operation each other. The application case shows that this method is fast, effective, stable and operable. And it can satisfy the need of integrated solid model dynamic accuracy in mining design and engineering management.