This paper carrys on a research on selection of reasonable mining method of C409 complex and hard-mining thick coal seam in WangJiazhai coal mine. First, in order to make the selection of mining methods much more convenient, conclude the general application conditions and selecting principles of three thick coal mining methods in the form of table. Second, concretely analyze the bad factors of C409 complex and hard-mining thick coal seams mining which we should especially consider. On the basis of these, make a comparison analysis of selection of C409 thick coal seam mining method and comprehensive evaluation of adaptability. The results show that it is reasonable to select top-coal caving method for C409 thick coal mining under present mining technology, which is consistent with the actual mining method at present. Finally, this paper gives a few of suggestions on some problems that may occur during C409 complex and hard-mining thick coal seam top-coal caving, which serves as a direction for C409 safely and efficiently mining.

Abstract: According to the inclined coal seam downward mining goaf digging roadway coal pillar size selection problem, this paper takes the responsibility of building coal 7259 airway as the background, using numerical simulation method to simulate the size of coal pillar from 3m to 10m roadway surrounding rock stress field and displacement field. The research results show that: 5m coal pillar width vertical force and peak has become stable, coal pillar exists some of the width of the elastic core, can bear induced by coal mining of abutment pressure of roadway influence. At this point, the displacement of the horizontal direction and the peak value of the horizontal displacement of the coal pillar is decreased, and the displacement of the middle level of the coal pillar is slower. The final determination of reasonable coal pillar size is 5m. Then, the size of coal pillar is calculated by theoretical analysis. The results of the two methods are quite different. The research results are used in the field practice, the deformation of the roadway surrounding rock is effective, and the maintenance effect is good.

Aiming at the intensely expansion of coal given chamber floor for 214 coal bunker affected by water in XiaShijie mine，the wall-mounted bunker was newly designed. The self-bearing system of wall-mounted bunker that was composed by I-beam joists，steel joist bracket of bunker body with fixed anchors and self-locking bearing anchors bear the full weight of coal bunker by utilization of bunker surrounding rock and make the dislodgment of bearing structure at the bottom of coal given chamber be realized. While using electroslag pressure welding，high-strength impact resistant materials and other advanced technology and new materials，the overall process of bunker wall-mounted was improved，the construction time of bunker was shorten，and the cost of construction and maintenance for coal given chamber also was reduced. Field testing proved that reliable，obviously technical and economical，the wall-mounted bunker is of good application in similar geological conditions.

The conveying process of large sized coals unloaded by the head roller of a TD75 belt conveyor was analyzed. The parabolic trajectory of large sized coals unloaded from the head roller was confirmed by calculating the kinematic trajectory equation, and the area of back plate of head funnel suffered strike severely by flowing coals could be positioned well by using geometric drawing approach based on this trajectory. According to the impact area , the structure of the head funnel was optimized. Two improved structures of head funnel, one with adjustable plate and another with the buffer area of dead coal pile, were designed. The two new improved structures of head funnel both can reduce the force of impact and abrasion resulting from flowing coals and decrease the noise and coal dust.

It has been a controversial issue in the field of the designation of big inclined wall in column-supported silo. Taking Han jia wan colliery of Northren Shaan Mining Co.,Ltd as an example.The paper covers the Calculation and analysis for two structure models of the normal and the vertical with Midas/gen. which represent the different schemes of Big big inclined wall in column-supported silo in coal preparation plant. Focusing on the Comparisons of mechanical properties of the two different schemes and ensuring the normal scheme is recommendation which can be used for the designation and study of the column-suppert silos. Focusing on the Comparisons of mechanical properties of the two different schemes and ensuring the normal scheme is recommendation which can be used for the designation and study of the column-suppert silos.

Abstract：In order to adapt to mine derrick design,with a coal mine in GanSu drilling derrick instance,proposed the existing derrick method of analysis which use the load combination of current specifications,and to analyze and verify the derrick skip head sheave and cage head sheave vertical arrangement.The results showed that:skip head sheave and cage head sheave vertical arrangement compared to only partial reinforcement can adapt to the requirements of conventional arrangement,and requires less reinforcement material,greatly reducing dependence of the terrain, with more strong applicability.

We have used a China, American and European regulations of concrete mix proportion design method, and we also have designed the mix proportion of shotcrete which strength grade is C30 and slump is 110 mm. Through the qualitative and quantitative analysis of three kinds of design steps and calculation methods, we have got the following conclusions: The effect of the amount of materials on the mix proportion is arranged in the order of the large to small is aggregate proportion, water cement ratio, water consumption or cement content; Determination of proportion of aggregate in China based on experience, the method of ACI is to determine the amount of coarse aggregate and then further determine the amount of fine aggregate, while Europe is get scientific and precise values by complex computation based on the FAURY method. By comparing three different methods we can see, choosing the same parameters, but the calculation of the mix proportion is different. Therefore, in actual engineering, we can combine two or three methods, so that we can better guide the shotcrete mix proportion design and construction work.

In light of the coal roadway deformation and breakage problems in soft rock conditions under dynamic pressure influence, the borehole TV and sonic wave testing were used to survey the failure modes and rules of roadway surrounding rock based on coupled supporting principle and broken-rock circle theory, and the failure mechanism of surrounding rock was obtained through numerical simulation. The combining passive and active support by cereals and supplemented by the coupled- strengthen supporting technology were designed in this paper. The results show that the loosen zone of the coal roadway sides is belong to the typical big loosen zone with a more acute roof-off-strata problem. It can substantially strengthen active supporting capacity by using deep anchor support and improve the self-bearing capacity and stability of coal pillar by optimizing the pillar size. It can realize multi-zone cascade bearing and overall strengthening on the roadway surrounding rock by using compound support technology which combine both passive and active support methods and coupled-strengthen supporting technology.

Research on the reinforcement technology for large section coal roadway with great depth and multiple disturbances of Sihe mine was carried out with methods of surrounding rock structure filed observation, the anchoring force test and underground experiment. Based on the observation and test results, the comprehensive reinforcement plan of deep-shallow hole grouting and high pre-stressed cable bolting was applied with the consideration of roadway deformation. Restore the original continuous state of broken surrounding rock with grouting, and improve the self-bearing capacity of surrounding rock with high pre-stressed cable bolting. Ground pressure monitoring results show that comprehensive reinforcement technology can effectively control the deformation and maintain a long-term stability of the main entry, and provide technique support for similar conditions.

In order to eliminate the threat of the high pressure water in the sandstone on the seam roof, the feasibility of the dewatering and depressurizing was studied by carrying out a large dewatering test underground before mining work and observing the water drawdown under different water discharge. The results showed that the total water discharge decreased from 223.2 m3/h(Y36-3)to 20-30 m3/h and the water pressure from 5MPa to 0.38MPa after a period of time of dewatering. The decline is obvious, so the conclusion was dawn that the way of the dewatering and depressurizing was feasible. The standard for mining work was put forward, which would play a foundational role for the later work.

Analysis based on the water burst accident occurred on cretaceous shallow coal seam of 1709-1working face of Duolun Xiexincoal mine in Inner Mongolia province, geological model is set up on the basis of borehole data, comprehensive analysis of the impact of mining working face of the aquifer, and find out the source of water, through the analysis of the characteristics of strata, we studied the causes of the formation of water channel, and confirmed the cause of water breakthrough that is the working face bedrock thinner thickness in coal seam outcrop area, as well as water flowing fractured zone affected to the basalt weak aquifer above the working face and supply by the border of strong water erosion. According to the actual situation proposed countermeasures for prevention and control of water disasters in the outcrop area of shallow face, and formulate measures for prevention and control of water safety, provide the safeguard for secure mining.

By using FLAC2D, the influence of different drilling diameter, drilling distance and burial depth to drillhole pressure relief has been simulated in this paper. It can be proved that : (1)After the drillhole was implemented, the stress concentrated in the left and right sides, either the stress pressure was relieved around especially both sides of the up and down of the drillhole.Meanwhile,the greater the diameter of drillhole, the better the effect of the drillhole pressure relief, the destruction of coal around the drillhole is becoming more and more serious. The distance of drillhole is smaller, the pressure relief effect is better. When the distance between the drillhole is large to a certain degree, the area and efforts of the drillhole pressure relief will not change.(2) When using the same drillhole diameter and less drillhole distance to relieve coal pressure, the height of the pressure relief zone are the positive proportion relation to the depth of the coal seam. With the increase of the drillhole distance, the height of the pressure relief zone is not changed with the depth, basically tends to the same height. (3) When the drillhole parameters is same, the depth of the coal seam is greater, the pressure relief effect is better. At the same time in order to better prevent rock-burst, different buried depth of coal seam should choose reasonable drillhole parameters . (4) The results of simulation analysis is applied to 7192 working face in Xu Zhuang Coal Mine, who have played a very good pressure relief effect. The working face is ensured to be mined safely by using drillhole . The research conclusion can also provide scientific basis for roadway pressure relief for rock-burst prevention under different depths and the following working faces of Xu Zhuang coal mine being mined safely.

For high efficient gas drainage from coal seam of underground mine, aiming to control the underground gas disasters,Since 2000, the VLD-1000 directional rig has been introduced into China for dealing with gas controlling for High Grade Gassy Mine and Coal&Gas Outburst Mine. Currently, the total quantity of VLD-1000 is 120. 108 of them are track rigs and others are modular rigs . Some VLD-1000 rigs are standing idle due to the limit practice and unripe technology in operation and running. Through analyzing misapplications of directional drilling technology such as tracking drilling plot, reserve branch point and branch-sidetracking, the counter-measures are selected accordingly for improving the success rate and efficiency of directional drilling.

In order to solve the problem of roof falling and rib spalling when Tang Jiahe 1813 mechanized mining face cross over anticlines. Use FLAC3D software to simulate the method 1813 Face crossing over anticline. Analyze the change of plastic zone, the stress range of workface supporting, the relative displacement of roof and floor under different mining method. Compare the advantages and disadvantages between two methods. The result shows, for crossing over anticlines of inclined coal seam, floor-excavating and roof-keeping straight mining method or relaxed curve mining method should be more used to control the stress of coal wall, floor and roof to ensure producing safety. Propose the corresponding control method of roof falling and rib spalling in different parts of workface: the upper face should use chemical agent to strengthen the coal wall; the middle face should excavate floor and keep roof; the lower face should use secondary support and man-made roof to cross over anticlines.

Mine water inrush are important factors affecting coal mine safety, water inrush of water is the basis for determination of coal mine water control work, but the results of a single water inrush Inrush Water Source method is often inaccurate results. This paper is mainly based on coal mine during mining face water burst case, by application of the elements analogy, fuzzy clustering method and three-line graph method piper Comprehensive Analysis of Water Bursting Sources Face three methods to identify mutual authentication result, improve the water judge accuracy. Final decision early Face Water from roof sandstone aquifer, with the water from sandstone roof dewatering Jurassic aquifer complements water mainly from the late Jurassic aquifer.

Based on the 3215 mechanized caving face in Wangpo gassy coal mine, it analyzed the methane drainage mechanism of mining crack field，and obtained the width of working face plastic zone, the distribution characteristics of overlying strata cracks, and the spatial position of gob area “O” rings by UDEC numerical simulation and theoretical calculation. Based on this, it also confirmed methane drainage design parameters of the pre-pumping drilling in coal seam, the high borehole along roof strike and the pipe laying gob area. Numerical simulation and theoretical calculation inferred that the coal wall plastic zone width of 3215 mechanized caving face is 8.2m, with the roof caving zone height of 12.5m, the fissure zone height of 45m and the gob area “O” rings horizontal width of 26m. Field practice shows that face gas pumping rate attained 45% to 52%, and the methane concentration at upper corner and return airway stabled 0.8% or less, which illustrated that the application of comprehensive gas control techniques on mechanized caving face effected obviously.

Abstract:In order to make more targeted gas prevention and control measures of Guizhou coal mines ,carry on the statistical analysis in time, place, gas disasters type and properties of coal mine of Guizhou coal mine gas accidents from 2007 to 2015.It is concluded that the gas disasters are the first major calamity in Guizhou coal mine, having the characteristics of timeliness, regional and local, coal and gas outburst as the main gas disasters category , tunneling faces as the main location, the local villages and towns coal mine gas accident is the worst-hit areas. At the same time, analyzing the reasons of the gas disaster, proposed comprehensive prevention and control measures of the regulators and the combination of coal mining enterprises to reduce the gas accident, and it is concluded that the key to reduce the amount of gas accidents is strengthen gas prediction in the process of excavation, control of local villages and towns coal mine supervision, focus on improving regional gas prevention and control ability of Liupanshui and Bijie.

Hydrocyclone has been widely used for coal slime classification ever since its invention. However, there is a limitation to hydrocyclone accuracy: even though much work has been done to improve its structural and operational parameters, there are still misplaced particles in underflow and overflow. It’s shown that particle density has a role in sizing effect by analyzing terminal velocity, equal settling ratio and density. This can be thought of as separation side effect and some suggestions about how to improve classification efficiency was be put forward.

Design of coal pillar are important factors in the prevention and treatment of percussive ground pressure. But as a result of ventilation, fire prevention and historical reasons, some mines mined with wide pillar. In mine roadway excavation in the process of dynamic appeared frequently, a serious threat to the safety production. In this paper, Cui Mu coal mine 21306 working face of engineering objects. Determined by numerical simulation and field microseismic monitoring, impact bias, syncline structure, coal strata along the empty coal pillar is the main influence factors of percussive ground pressure of 21306 roadway. In the excavation process has adopted advanced pressure relief, two sides and bottom pressure relief measures. Pre-splitting blasting in the drainage areas has been done besides the roof. Through the above measures, lane 21306 machine in the process of excavation, significantly reduce the dynamic phenomenon, roadway, to not impact accidents, ensure the safety of along goaf roadway.

With numerical simulation，theoretical analysis and field measurement applied，the characteristics of roof failure and its influence factor and determination of support resistance of face during fully mechanized caving were studied, which the engineering background is 1109 fully mechanized caving face production technology in Xichuan coal mine. Research shows that upper immediate roof of 1109 fully mechanized caving face periodically breaking lead to face weighting, and the main factors that influence upper immediate roof periodically breaking were upper immediate roof thickness and overburden weighting. The main factors that determination working resistance of support were upper immediate roof periodic caving span and support face wideth and additional force acting position and the force of lower immediate roof to upper immediate roof away from the coal wall. And it calculated the reasonable resistance of support of 1109 fully mechanized caving face. Field measurement show that ZF6400/17/32-type hydraulic support working resistance could meet the requirements of roof supporting，and could effectively support roof, and ensure face safety production. Key Words: fully mechanized caving face; upper immediate roof; combination cantilever beam; periodic breaking; working resistance of support

Underground coal mining will lead to surface displacements and deformations, which will change the original surface topography. As a result, regional surface streams and their characteristics are influenced, and eco-environment gets serious impacts. According to the original terrain, mining geological condition and plan of a coal mine in south Anhui Province, this paper used the probability integration method to predict the mining subsidence from 2014 to 2035. Based on the special analysis function in the ArcGIS software, original surface topography in 2014 was considered into the simulation of surface subsidence after mining, and DEM were contracted both in 2014 and 2035. Then, surface streams and their features in 2014 and 2035 were extracted and analyzed by using the hydrological analysis module respectively. By contract, it was found that, the underground mining resulted in big changes of topography which affected flow direction and total stream length in different levels. The number of main streams decreased from 4 to 3. The length of longest stream reduced by 2154 m. The direction of one stream even reversed in 2035. The catchment basin also combined, extended or shrunk, which would alter original special distribution of water catchment. This research will provide important reference for regional water system programming, land use plan and land reclamation design.

To get more accurate prediction of the gas distribution area and to provide basis for the coal mine robot to avoid the dangerous area of gas, this paper presents a new method for prediction of the gas distribution ahead 10m of coal mine robot by using HPSO-GNN. Experimental results show that the average relative error of gas concentration predicted by HPSO-GNN is 4.83%, and the overall prediction accuracy of the HPSO-GNN prediction method is improved by 57.48% compared to the GNN prediction method, the predicted results of gas distribution area are in good agreement with the measured values. The method can accurately predict the gas concentration distribution area, and provides a basis for the coal mine robot to avoid the dangerous area of gas.

Abstract: A loading mode of air cylinder was designed for mining research of mines buried less than 1500m in similarity simulation experiment of plane stress model. The designed loading mode needs 16 air cylinders with an inner diameter of 16mm and a stroke of 200mm. Based on practical application, the designed loading mode has the advantages of stable pressure, timely follow-up, low pollution and cost, no long-term maintenance compared to traditional loading modes.

This paper introducethebasic principles of grith compressed air ejector, which mainly studied the effect of different material and thickness of the gap adjusting shims on the performance of the ejector device, meanwhile study the influence of working pressure, surface shape of the intake of air collector, flange arc radius on the influence of air volume and air inflow of ejector ,the result show that the material of shim have a big influence on the import volume of ejector， effect will be the best when the shape of the intake air collector is conical and the more suitable range of the flange arc radius is 4-8m, should make full use of ejector’s optimal performance during the actual use process.

In the power quality management of coal mine power grid, Active power filter (APF) and other switching compensation devices have been widely concerned. The special requirements of power quality management for coal mine power grid, an optimal control of APF reference compensating current under non sinusoidal supply voltage is proposed. By analyzing the constrained conditions, the objective function, equality constrain and inequality constrain are obtained that establish mathematical model of Lagrange multiplier method. In order to obtaining the desired source current and achieving the maximum power factor that calculate the optimal conductance factor for the nth order harmonic using the mathematical calculation. This control algorithm does not need complex iterative calculation, the calculation speed is simple and fast. Matlab simulation validate the feasibility of the proposed algorithm.

In view of the influence of electromagnetic environment on the work and safety reliability of the electric control system of mine hoist, the various forms of electromagnetic interference are analyzed, and the action mode and the corresponding measures are mainly studied. Field application results show that the anti jamming effect of the electronic control system is obvious.

Abstract: In order to further study the microscopic pores structure and adsorption characteristics of coal reservoir, the coal samples in Hancheng mining area of Carboniferous Jurassic and Permian system are selected to conduct the low-temperature adsorption of carbon dioxide and nitrogen adsorption/desorption experiments and the microscopic pores structure of different lithotypes were discussed. On this basis, the methane isothermal adsorption technology was carried out and which would be compare the adsorption characteristics of different lithotypes. The experimental results show that because of the different lithotypes, the D-R specific surface area and the total pore volume of D-A aredifferent. From the dull coal to the bright coal, the content of micropores increases with the increase of the content of the vitrinite and the D-R specific surface area and total pore volume of D-A also show an increasing trend, but the BET specific surface area and the total pore volume of BJH trend show the opposite. Therefore, compared with the bright coal which have the high content of micropores, the dull coal that with the low content of micropores have the poor adsorption capacities, and followed by the semibright coal and the semidull coal. In terms of the pore structure of the different lithotypes , the bright coal and semibright coal are generally the type I which one end are closed, the semidull coal is mainly based on the open typeⅡ, while the dull coal is the typeⅢof "ink bottle pores"

Based on the analysis of sample tests, this paper studied the distribution characteristics of trace elements in coal of Xinyu Meishan coal mine area, and the change rule of vertical distribution in different coal seam. Preliminary discussed occurrences of trace elements enrichment in coal. Research shows that firstly, Ga, U, F, P, As , etc. trace elements have higher content compared with average data of China, while the content of Ge, Cl element are below the average contents of China. Ge, U ＆ As are obviously richer than the average content of the earth's crust, the enrichment coefficient(EF) of these elements exceed 1,U element especially rich (Ef=19.38). The trace elements content of lower coal seam are relatively higher than that of the upper coal seam in the same coal. Trace elements of Ge,U,Cl and P are mainly associated with inorganic matter in coals, Ga,FandAs are mainly associated with organic matter in coals, Ga and F mainly adistribute in clay minerals, As is mainly in pyrite.

In order to achieve the upgrading of lignite and solve the problem of drought and water shortage in main producing area of lignite, the water quality of condensed water with different drying media were carried out with a fixed bed reactor and an inductively coupled plasma mass spectrometry. The gas production rate of coal samples under different drying temperature was also analyzed. The results indicate that two different particle size of coal samples with extended drying time, moisture content of coal sample reduced gradually, and dehydration temperature is higher, the lower the moisture content. Some small molecular compounds in the structure of the coal molecules are partially pyrolysis with the increase of the dehydration temperature, leading to the content of COD in condensate water was produced from dry coal sample with particle size of 6 to 3 mm under the atmosphere of oxygen at 140℃ was 230mg/L. With the increase of the dehydration temperature to 280℃, the content of COD in condensate water of dry coal sample increased rapidly to 37800mg/L. The values of COD, BOD, NH3-N and TON in condensate water was produced from dry coal sample with particle size of 0.5 to 0 mm are slightly larger than 6 ~ 3mm coal samples under the same drying conditions.Four kinds of heavy metal ions in condensate water as the dehydration temperature rises, the amount of precipitation were increased gradually. However, the content of heavy metal ions in the condensate water is much lower than that of the surface water environment quality standard V. When oxygen is used as a drying medium, the CO2 and CO are produced in addition to the decomposition of the coal sample itself, and the other part of CO2 and CO are produced from the weak oxidation reaction of coal samples during the drying process.

The rheological properties of dense-medium suspension in coal separation was related to the solid volume concentration and coal slime content. The prediction model was established by measuring the dense-medium suspension viscosity under different shearing rate to study the influence of volumetric concentration and coal slime content of medium suspension on rheological properties. The experiment results have shown dense-medium suspension viscosity increases with the increment of volumetric concentration under the given coal slime content. On the other hand, the viscosity decreases with the increment of coal slime content increasing under the given volumetric concentration. The predict model of the dense-medium suspension viscosity demonstrated that the lower limit of separation of dense medium separator is 13mm and coal slime content of dense-medium suspension should be less than 0.30.

Added sodium silicate as depressant in flotation can to reduce the ash content of of concentrate and improve the separation effect. The ash content reduced by 2.13% with sodium silicate 1000g/t. Based on the flotation experimental results and grey system theory, a forecast model GM (1, 1) for coal flotation with sodium silicate was proposed. The precision of the model is high through the checkout by posterior variance examination. The results show that GM (1, 1) is a valid forecast model to estimate the effect of coal flotation with sodium silicate.

For the realization of the knowledge management and sharing of electric traction shearer parts, the paper analyzes the overall structure and organization of knowledge base and studies the principle and method for building knowledge base. The case base of hierarchy level is built based on the case template foundation theory by the definition and edit of shearer cases. The parametric design method of geometric constraints and engineering constraint are used to build parametric parts library. The material case is built according to the material properties to realize the storage and query of material information. Based on UG platform, the parts knowledge management system of electric traction shearer is developed by using UG secondary development and data base technology. Through the enterprise application, the proposed method improves the design efficiency and provides a knowledge service platform for designers.

According to the working characteristics of mine roadheader in coal production process, a new type of automatic control system is designed. The system uses PLC S7-200 as the core controller, the hardware and software design are introduced in detail, the control system of safety and environmental adaptability methods are also given, the maintenance of the control system and motor are presented, the control system is fully functional, safe and reliable, it can fully meet the needs of coal production.

Abstract: The roadheader is the main equipment of coal mine comprehensive mining in our country, and the scraper conveyor is located behind the roadheader’s loading part, it is a major part for roadheader’s coal transport. As the roadheader technology rapid development, we also encounters many problems about the scraper conveyor with the process of actual using, such as scraper conveyor was jammed, scraper conveyor large gradient transport capacity was declined, scraper conveyor produced dust. In this thesis, through the in-depth analysis about the scraper conveyor, we put forward some improvement measures on the above problems. We hope the thesis could provide some theoretical guidances for the design of roadheader’s scraper convey.

Abstract: Aiming at the problem of manual control of hydraulic system for the hydraulic winch in coal mine, proposed rehabilitation programs of electro-hydraulic proportional control for drive and braking systems, closed-loop control of hydraulic winch lifting speed and coordinated control of drive and braking systems are implemented, these effectively improve automation level and speed accuracy of coal mine hydraulic winch. Experimental results show that the scheme can effectively improve the speed control precision and stability of hydraulic winch, At the same time, the design of parallel dual system to further protect the safety of coal mine hydraulic winch.

Taking a scraper chain conveyor as the research object, this paper studied the performance analysis and structure optimization method for the scraper chain. Structure and shortcomings of the original scraper chain were analyzed firstly, and stiffness of the scraper chain was finite element simulated. Taking yield strength of the scraper chain as the evaluation index, the simulation results show that the maximum load that can be endured by the original scraper chain is 3.41×104 N. In order to improve stiffness of the scraper chain and working stability of the scraper chain conveyor, optimization structure of the scraper chain was proposed. The simulation results show that the maximum load that can be endured by the optimized scraper chain is 7.85×104 N. The optimized scraper chain was manufactured and utilized in actual production. The results show that the optimized scraper chain conveyor have advantages of stable operation, high efficiency and high stiffness. Properties of the scraper chain conveyor after optimization improved significantly.

Analysis the conditions for the method of the lowest evaluated bid price systematically. The evaluation system and content of the lowest evaluated bid price method are systematically expounded on the three aspects of qualification examination, technical bid review and commercial bid review. The definition method of individual cost of enterprise is put forward, and to the leading role of the good for the further promotion of the evaluation methods.

Aiming at the frequent accidents of coal mining,and some loopholes exist in link of emergency management and lack the bonds of the emergency management and emergency response ,a new management system is put forward,in this system emergency management and the business continuity management are integrated. this paper will state the foreground and the construction of main point.Analysis showed that the business continuity management can recognize the disaster and provide effective mechanism to reduce the damage in case of key business interruption,so that this system will bring huge economic and social benefits for the coal industry.Business Continuity Management is a new set of management methods which can recognize the disaster and provide effective mechanism to reduce the damage in case of key business interruption .This method has been developing in banking、oil、paper money printing and Social public security industry but has not yet been used in the coal industry.In view of the frequent accidents of coal mining , and the existing emergency management are imperfect in the formulation and application,a new way is put forward that the business continuity management will integrate with emergency management in coal mine management system,state the foreground and the construction of main point .The application of this system will bring huge economic and social benefits for the coal industry.