Under the background of China’s coal-based clean energy strategy, the environmental impact post-assessment system promotion of coal mining is imminent with the rapid development of the national environmental protection system reform. In this paper,the key contents of environmental impact post-assessment for coal mining were analysied systematically, the opportune?moment to assess environmental impact and service cycle were discussed.The paper will provide technical support for formulating Technical Guide named Environmental Impact Post-assessment of Coal Mining and promote the environmental impact post-assessment system.

According to the geological conditions of close distance coal seams of Xiangyuan Coal Industry, theoretical analysis, numerical simulation, field monitoring are combined to optimize the roadway layout and support scheme for the combined mining of coal seams 2#, 3# and 4# of Xiangyuan Coal Industry. By discussing the mining methods of lower coal seam roadway and the analysis and calculation of the damage of the lower coal seam caused by the mining of the upper coal seam, the paper puts forward that the coal seams 3# and 4# adopt the same directed and the inner dislocated layout and the inner dislocation distance is at least 3m, which can be appropriately increased. Combined with the mine site observation of the deformation of the surrounding rock of the roadway, it is proposed that when the local layer spacing becomes smaller and the anchor cable cannot be constructed, “the anchor net beam + 11# I-steel shed” should be adopted. The results show that the proposed roadway layout of coal seams 3# and 4# is more reasonable, and the optimized roadway support scheme has obvious effect on maintaining the roof and floor area of the surrounding rock. At the same time, the research results also provide a reference for other mines with similar geological conditions to reasonably arrange and support roadway.

The low-power wireless transmission of high frequency signal has always been a difficult problem in coal face. According to the specific environment of working face and the characteristics of multi-class wireless bus communication, a kind of wireless vibration sensor based on Bluetooth and a diagnosis and a kind of analysis device based on Bluetooth and Lora with Android and embedded dual-core are developed in the research. The research has realized the vibration diagnosis analysis of different kinds of rotor equipment in the working face and ensured the long-term stable operation of key equipment in the working face, which can reduce the labor intensity of the staff.

The spontaneous combustion coal seam of fully mechanized top-coal caving mining has the characteristics of relatively slow advancing speed, large primary caving space in goaf, serious air leakage as a whole, and lots of floating coal left over, which is easy to cause coal spontaneous combustion disaster. In order to effectively monitor coal spontaneous combustion during mining and improve the early warning effect of coal spontaneous combustion, XD-JX-T001 distributed temperature monitoring and early warning system was developed and applied in No. 42223 working face of Chaijiagou Coal Mine. Through the analysis of temperature and CO monitoring data in the initial mining stage, mining period, final mining and withdrawal period, it is concluded that the XD-JX-T001 distributed temperature monitoring and warning system can realize the continuous monitoring of goaf temperature, accurate positioning and strong reliability, and can accurately identify the spontaneous combustion of coal.

In order to improve the value of coal in Tongxin,enrich product structure,ensure product quality and increase economic efficiency,according to the raw coal features and the market demand,the feasibility of producing 1/3 coking coal from Tongxin raw coal was studied，finally，a flexible washing process of producing high-quality thermal coal and low-ash clean coal products was finalized.The results show that the new process can take into account the flexible production methods of producing 1/3 coking coal and high-quality thermal coal，can achieve rapid and flexible conversion according to market demand，enrich the product range，and enhance the company's competitiveness and comprehensive profitability.When producing low-ash clean coal，the Middle coal and other by-products can be blended with the first stage cleaned coal to obtain a blended coal that satisfies the demand for sales，further increasing the value of coal in Tongxin.

Aiming at the Longmenxia-South Coal Mine encountered karst caves in +623m air return adit during construction，6# karst cave is the most complex， uses a combination of dredge and plugging，Using pebble filling and laying drainage pipes to ensure the cave water flow passage, casting the steel rail and reinforced concrete for plugging the caverns, set up the drain pipe in the cavern, install the waterproof gate valve and the pressure gauge,when water pressure overlimit，automatic emission，effectively solving the problem of cavern support and safety.

In order to solve the support problem of roadways at large cross-section intersection points in underground coal mines, especially the problem of stability maintenance of the surrounding rock of the wedge-shaped wall with broken "ox nose" at the intersection points of special sections under isolated island pillars, combined with the engineering example of cross-cut intersection point of Xutuan Coal Mine-500 horizontal track, the failure and deformation characteristics and causes of the "ox nose" wedge-shaped wall of roadways at large cross-section intersection points are analyzed and summarized. Based on the theoretical analysis of the model, it is proposed that the stability of the wedge-shaped wall and rock pillar is the main factor controlling the overall instability of the roadway at the intersection point, and a new grouting pre-reinforcement technology for the broken wedge-shaped wall and the reinforcement support for the tension anchor cables are proposed. Engineering practice shows that the technology can effectively reinforce and control the deformation of the surrounding rock of the wedge-shaped wall broken at the large cross-section intersection point under the isolated island coal pillar, improve the overall stability of the intersection roadway, and play the mutual control effect between the top and bottom of the intersection roadway; after 70 days of repair, the deformation of the intersection point tends to be stable, the displacement of the two sides is less than 100 mm, and the displacement of the roof and floor is less than 85mm.

In response to the domestic problems concerning the low recovery rate of coal resources and the traditional long-arm mining method, the technology of roof cutting pressure-relief and automatic roadway with no pillar is proposed. This technology can not only increase the recovery rate of coal resources and reduce the amount of roadway excavation, but also realize the safe and efficient mining without pillars. In this paper, under the guidance of the technology theory of roof cutting pressure-relief and automatic roadway without coal pillar mining, taking the 8304 working face of Tashan coal mine as the engineering background, before the pre-splitting blasting of the roadway roof, the constant resistance large deformation anchor cable was used to reinforce the original support of the retaining roadway roof in order to control the roof deformation and ensure the success of the retaining roadway. The design adopts length of constant resistance large deformation anchor cable is 9.3m and the support density is 0.8 per square meter. The design has been applied to the field to achieve a good lane effect, indicating that the constant resistance anchor cable has an important supporting effect on the roadway roof. At the same time, it can also provide certain reference for the application of the technology in roof cutting pressure-relief and automatic roadway with no pillar and roof support under similar conditions.

In order to solve the large deformation problem caused by faults in the roadway along the roadway with empty top cutting, the displacement of the roadway and the monitoring of the roof separation were used to obtain the deformation law and surrounding rock structure of the surrounding rock after the roadway was broken. A layered grouting technology with a new type of inorganic grouting material and grouting technology as the core, grouting reinforcement treatment of the roadway. The engineering practice results were shown that after the layer grouting reinforcement, the surrounding rock deformation was quickly controlled, the roof subsidence was controlled within 25mm, and the roof separation was only about 2mm; the roof watering problem is solved, and the surrounding rock fissure is effective. Filling and strengthening, the roadway deformation entered a stable stage, which can meet the later use.

To ensure the safety and quality of the roof structure of coal storage bunker constructed with Bailey truss platform, the mechanical characteristics and the measures for improving the bearing capacity of Bailey truss platform are analyzed, and the main operating points and key construction techniques of the technology are introduced.

The effect of grouting reinforcement of floor is closely related to geology, hydrogeological condition and grouting engineering of the working face. Taking the 14141 working face of Jiulishan coalmine in the typical water-abundant Jiaozuo mining area as engineering background, this paper statistically analyzed the geological and hydrogeological information and parameters revealed by a large number of floor grouting boreholes, evaluated the conditions of grouting reinforcement, and further provided a method to assess the grouting effect. The conclusion of research showed that the water abundance in the floor was partitioned according to the water inflow in the grouting boreholes, based on which the positive correlation between the water inflow and water pressure was obtained. It was shown that the water abundance in L8 limestone aquifer was weaker than that of L2 limestone aquifer by analyzing the outflow frequency and total water volume in different depth, and impact of faults on water abundance in the floor and grouting effect was significant. By analyzing the dynamic relationship among water inflow, water pressure and grouting volume comprehensively, it was found that the water pressure was kept increasing as the grouting continued, which reflected that the fissures in the underlying strata were effectively grouted, and increased local tightness of aquifer. The results indicated low water pressure, low flow rate and low grouting volume were the signs of ideal grouting effect.

the hydraulic pressure enhancement technology combined with drilling is an effective technique to improve the permeability of coal seams. Xintian coal mine in Guizhou mining area has the characteristics of high gas content, high pressure, and low gas permeability. For low gas drilling concentration, fast flow attenuation, long management time, and difficulty in management, the problem of efficient gas extraction can not be effectively solved. In order to improve the effect of gas extraction, shorten the gas treatment time and increase the permeability of coal seams, the hydraulic pressure reduction and increase penetration technology was implemented at the bottom of the 1404 transport ditch in the 1404 working surface, accelerating the efficiency of excavation and extraction in the 1404 coal lane, and reducing the time required for pumping and mining. It has improved the speed of coal roadway excavation and effectively eased the tense situation of "pumping, digging, and mining".

In order to realize the rapid and safe coal uncovering under the complicated geological conditions of the roadway tunneling fault group and the coal seam group, the grouting/solidification/cutting comprehensive anti-burst technology is proposed based on the prevention mechanism of coal and gas outburst and the supporting mechanism of broken surrounding rock. The technical test was carried out with the construction of Wulunshan Mine Transportation Roadway as the engineering background. Firstly, through the pipe shed + grouting support technology, the surrounding rock of the excavation roadway is controlled ahead of time to prevent the roof from inducing the protrusion. Secondly, the grouting and solidification technology was applied to grout solidify the full-section coal and rock mass of the excavation roadway, improving The structure of coal and rock mass reduces the K1 value of the prominent index. Finally, the gas isolated from the fault group was separated from the coal seam group by the grouting and solidification, and the grouting/solidification/cutting comprehensive anti-burst technology system is formed. This technology not only prevents the outburst, but also strengthens the support to ensure safe and rapid excavation of outburst coal seams group in the fault group.

In order to effectively solve the problem of gas control in the corner of the fully mechanized caving face, the gas drainage technology of high-oriented directional long borehole is adopted. To study the correlation characteristics between high-level directional drilling and gas drainage,fully mechanized caving face of Wangjialing mine is used as the tracking object, and the influence of different offsets and intervals on the concentration of extraction and the amount of pure extraction is analyzed from the horizontal and vertical intervals,Then the best layer of pores in the same zone and the wrong zone is obtained. Through the on-site application of the high-grade directional drilling test in Wangjialing Mine, the maximum concentration of gas at the corner of the production work surface is reduced to 0.64%, achieving safe and efficient production of the fully mechanized caving face.

In order to basically solve the previous problems of the open hole multilateral branched horizontal well, such as collapsing, clogging, having difficulties to dredge, operate and increase production, the theory of controllable horizontal well has been put forward, which is aiming to control the hole, reconstruct easily, operate fast and effectively, and be applied into reality widely, through the improvement of the structure of the second spud well with full bore, non-drilling half range cementing, the drilling fluid stabilization of less damage to the side-wall, drilling methods and completion technology. Meanwhile, whether the horizontal segment of the well is upward sloping or downward sloping, rod pump can be set into the well to drain directly without drilling drainage cavern well, which decrease the drilling investment to a large extent and has a positive effect on factory development of horizontal well groups. Huabei oilfield CBM area has promoted and tested more than 70 wells, guaranteed the drilling successfully rate to be 100%, decreased 45% of the total cost of drilling and draining, compared with open hole multilateral branched well, and increased the production in 1.89 times than open hole multilateral branched well. In conclusion, the Huabei oilfield CBM area has achieved the goals of low cost and effective development.

Due to the high level horizontal stress in the deep underground, the deformation of haulage roadway in the third mining section of Nanguan Coal mine is large and it’s hard to support. To control the roadway’s stability, the stress evolution law and failure mechanism after excavation has been studied by field monitor, numerical simulation and theoretical analysis, the synergetic support that bolts and cables are layout in the same row has been presented, and the prestress field and deformation of surrounding rock has been compared. It turned out that, only after both the layout and prestress of bolts and cables are synergetic, can the mechanical property of anchorage structure be used better. The synergetic support has improved the self-supporting capacity and decreased the deformation of surrounding rock. Field application and monitoring data shows the synergetic support achieved practical supporting effect and the stability of roadway was effectively controlled.

The rock burst is the main coal-rock dynamic disaster in the steeply-inclined coal seam, which is highly destructive. In order to timely and accurately identify the strike and the tendency stress concentration zone of working face, reasonable design of pressure relief and protection measures, the stress evolution process in the advanced area of the working face was continuously monitored by stress online monitoring system. The monitoring results show that: in the strike direction, the influence of the lead support pressure is 5-20 m ahead of the working face, and the tendencies stress concentration zone is 6-13 m away from the roadway wall, which is different from the horizontal and gently inclined coal seam. After the research results were applied to guide the implementation of the on-site pressure relief project, the stress concentration in the above areas was significantly reduced. The above research has important guiding significance for the steeply-inclined coal seam pressure relief projects

Mining deep Jurassic coal seams in the Ordos Coalfield are seriously threatened by overlying sandstone fissure confined aquifers of Yanan Formation and Zhiluo Formation. During roadway excavation and working face mining of Jurassic coal seams in many mines, the water inrush accidents happened, these seriously influenced the safe production of mines. Took the Jurassic 3-1 coal seam mining in the 302 area of the Muduchaideng Coal Mine as research background, and based on the full analysis of the geological and hydrogeological conditions of the mine, combined with the application situation of the long-distance directional drilling technology for gas control and water prevention and control in coal mines in China, we put forward the technology of regional control for roof thick sandstone aquifer, whose cores are using boreholes in outer roadways of working face for diversion, using boreholes in adjacent working face for closure, using double side goafs for closure and using long distance directional drilling to trace and release water. The application results show: the technology is economical and feasible, during the roadway excavation of the working face, it has less impact on the roadway excavation construction; it can realize the “regionalization prevention and control, separating coal and water separation, diverting clean water and turbid water, regional treatment” for the roof water of the coal mining face; the water hazard of the water-rich roof sandstone aquifer is well solved, under the condition of the water inflow from single roof water discharge hole more than 200 m3/h and the water inflow of the working face more than 600 m3/h, the safe production and an average recovery efficiency of over 12 000 t/d were realized in the full mining thick coal seam. The technology of regional control for roof thick sandstone aquifer explored a feasible treatment method of regional control for thick roof sandstone aquifer in Jurassic coal seam in Ordos Coalfield, it can provide a guarantee for mine safety, high efficiency and green mining.

To solve the problem of mining under safe water pressure of aquifer with high water pressure and thin traditional water-resisting layer in lower coal seams of Zhaozhuang coal mine in Shanxi Jincheng Mining Group, by adopting hydrogeological drilling, pumping test, water injection test, in-situ stress measurement and indoor test, based on the comprehensive study on the lithology, filling situation of fractured karst, drilling leakage, rock mechanical index and permeability test in the top of Ordovician limestone, the relative water-resisting property of rock strata in Fengfeng?Formation in the top of Ordovician limestone which is the floor of lower 15# coal seam is demonstrated. The results show that:1) the lithology of the upper Fengfeng Formation existed in the top of underlying Ordovician as floor of 15# coal seam in Zhaozhuang coal mine is dark grey, dense, hard and thick-layer limestone with less dolomitic limestone and marl, which has high strength and a large number of irregular filled fractures and constitutes strata of poor permeability. 2) There is a layer of relative aquifuge with at least 30 meters thick existing in the top of Fengfeng?Formation of Ordovician limestone. The thickness of underlying water-resisting layer as floor of 15# coal seam is between 38.75~67.25 meters and the average thickness is 57 meters, which has better water-resisting property. 3) The risk assessment of water-inrush during mining lower 15# coal seam in Zhaozhuang coal mine is performed by the method of water-inrush coefficient, which shows that the risk of water-inrush can be greatly reduced by applying the relative water-resisting layer in the top of Ordovician, and then a great amount of coal resources will be released.

Abstract: Based on the flowing characteristics of pulsating water injection in coal seam, the effect of water injection on porosity, water absorption and gas desorption was studied through the laboratory experiments. The results show that: (1) Under the action of pulsating water pressure, the effective influence range in the early stage and the reduction degree in the later stage of the fractures are both related to the hardness of the coal body itself. With the increase of the time for coal seam water injection, the growth rate of the effective influence range of water injection fracturing gradually decreases. (2) Coal seam pulsating water injection is beneficial to the development and expansion of coal fissures. However, it has little effect on the limit water injection of coal. The limit water injection of Sihe coal mine has only increased by 3.53%, one of Changping coal mine 2.76%. (3) After the water is injected into the coal seam, it is favorable for gas desorption in the early stage, but there is a water lock effect in the later stage. The gas desorption test of coal seam pulsatiing water injection in 4318 working face of Pingding coal mine also proves this conclusion. Therefore, according to the actual situation of coal mine, the water injection time is determined. The coal seam anti-burst can neglect the water lock effect. However, for gas mining, the measure of gas drainage is given priority should be taken.

As the time change ,coal in the process of oxidation temperature will desorption to produce CO, CO2, CH4, C2H6, C2H4, and other gas. For a long time ,coal spontaneous combustion prediction only considers the internal factors and external factors ,and has not yet to consider a self-heating effect on coal spontaneous combustion feedback. Based on zhao lou coal mine as the background, use gas component analysis and neural network algorithm to establish the BP neural network prediction model, select CO, CO2, CH4, C2H6, C2H4 gas concentration as neural network input layer, the coal temperature as output layer, set up eight hidden layer neurons in the forecast of coal spontaneous combustion. The result shows that after training, the predicted temperature and real temperature error control between 0 to 0.00065. The establishment of the prediction model for coal mine spontaneous combustion has an important guiding significance.

In order to improve the strengthening effect of cement-based grouting material on expansive loose and broken soft rock. In laboratory, the fluidity, consolidation rate and compressive strength of the grouting material reinforced by XPM nano grouting agent cement anchor grouting were studied.The suitable ratio of the grouting material is found. That is, the dosage of XPM nano perfusion agent is 8% to 10%, and the water cement ratio is 0.5~0.6. The experimental results show that the use of XPM nano perfusion agent can significantly reduce the amount of water, slow down the segregation precipitation, improve fluidity, and enhance the injection rate. It can shorten solidification time, reduce shrinkage rate and improve curing strength. It lays a foundation for ensuring the quality of grouting construction. And it has been successfully applied in the repair and reinforcement of the roadway of the car yard at the bottom of the shaft in Yuxi coal mine.

The paper presents a type of jointed mobile robot with double tracks about colliery rescue, the tracked robot platform consists of front and rear segment. When the robot climbs over obstacles during the process of colliery rescue, the front and rear segment can form a certain angle by rotating the joint, which can effectively solve the complex problem of inadequate surmounting performance about double-track robot. The design of passive regulating device can prevent from the track slacking or falling off when the robot climbs over. Based on the study, we analyze surmounting performance of the robot for the instance of climbing over the steps. In the last, we verify the correctness of theoretical analysis and the validity of the structure design of the jointed double-track robot by means of the experiment

In order to improve the stress condition inside the wire rope and prolong the service life of the wire rope, The structure of 6 × 36WS wire contact wire rope for shaft hoisting is improved based on the characteristics of the surface contact wire rope. The contact area of steel wire is increased by adding independent contact wire core between the side wire and rope core of the wire rope, so as to improve the service life of the wire rope. Through the establishment of mathematical model to study the influence of the force on the wire rope, it is concluded that the helical angle is the main factor affecting the force of wire rope. A simple strand wire rope model with different helix angles in different periods was established. Under the same load conditions, simulations were performed through ANSYS. The results show that internal stress state of the steel wire rope can be effectively improved with the independent contact core structure.

Aiming at resolving air pollution caused by explosion proof diesel engine vehicle, the application of explosion proof electric vehicle grew apparently. Related to core indications, such as driving range and charging time, power battery technology is a key technology of electric vehicle. According to different suitable vehicle types, colliery power battery was divided into special type explosion proof lend-acid battery and flameproof lithium-ion battery. Based on actual application cases, the feature and their suitable situation were analyzed separately. It was concluded that special type explosion proof lend-acid battery would be the major energy system solution of heavy operating vehicles for a long time. Because of extra weight caused by flameproof box, the advantage in energy density of lithium-ion battery could not reflected adequately. Energy density extension of flameproof lithium-ion battery and reliability promotion of battery management system would be the development direction of flameproof lithium-ion battery.

Abstract: Taking the actual feed height 2m of SSC70150 sizing crusher as the background, the three-dimensional model of double tooth roller of sizing crusher is established by SolidWorks, and the Hertz-mindlin with Archard Wear built-in contact model is used to Through the Gold segmentation experiment design and combined with the field use of SSC70150 sizing crusher, the Edem simulation software is used to simulate the crushing process of the double tooth roller of the sizing crusher. By changing the feeding height, the wear condition of double tooth.

For using the jet flotation machine effectually, study the effects of different aeration volumes and foaming agent parameters on flotation, using a self-made jet flotation model, The self-made spray flotation model was used to simulate the effect of flotation aeration and foaming agent concentration on concentrate yield. The results show: aeration volumes changes the shear strength of the fluid, in the case of the same pulp concentration and foaming agent concentration, The aeration amount has a critical value of 400L/h, which is less than the critical value. The flotation concentrate yield increases with the increase of the aeration amount, greater than the critical value, the effect is deteriorated; The blowing agent concentration also has a critical parameter of 0.1 mmoL-1. Therefore, controlling the amount of aeration and the concentration of the foaming agent during the operation of the jet flotation machine is an important way to adjust the concentrate yield.

Abstract: To explore the effect of polyaluminum chloride (PAC) of different concentrations in coal flotation, flotation rate experiments were conducted with the mixture of coal (250-125 μm) and kaolinite(- 100 μm). Water recovery, gangue recovery, entrainment index, Efficiency Index (EI), Separation Efficiency Rate (SER), and Se-lectivity Index (SI) were used to evaluate flotation performance. The experimental results show that the addition of PAC can reduce water recovery, gangue recovery and entrainment index. The three flotation evaluation indexes (EI, SER, and SI) showed that the optimum flotation efficiency was obtained when the PAC concentration was 20mg/L. PAC of different concentrations was used to agglomerate kaolinite, and the unweighted chord length distribution of kaolinite suspensions was measured by the Focused Beam Reflectance Measurement (FBRM). FBRM measurements showed that with the increase of PAC concentration, the chord length distributions of kaolinite increased first reaching the peak at 20 mg/L and then decreased. Bubble-particle attachment probability measurements were car-ried out with the coal which was interacted with PAC of different concentrations. The bubble-particle attachment probability measurements showed that PAC reduced the hydrophobicity of coal particles, which matched well with the reduction of flotation rate.

According to the hard and difficult treatment of slime cementation in Tian-hong coal preparation plant, this paper compares the traditional flocculating agent #1 and #2 with the new flocculating agent AL9020, and applies them to the settling test of slime water and analyzes its effect. Firstly, the slime was screened and X-ray diffracted, and the flocculating agent AL9020 was analyzed by infrared spectroscopy. On this basis, laboratory flocculating agent settling test and industrial flocculating agent settling test were carried out for slurry water, and the mechanism of the influence of three flocculants on the settling characteristics of slurry water was discussed. The results show that the slurry water has fine granularity and high clay mineral content. It belongs to typical high-sliming refractory slurry water. AL9020 has the best settling effect. The height of clarification zone is 18.4 cm and the transmittance of supernatant is 73.2% after 6 minutes in laboratory test. When the dosage is 14g/t, the concentration of overflow water is 1.5g/l.

In actual situation, the force of scraper and scraper chain of scraper conveyor is the pulse force, and there is severe pressure fluctuation during the working process. Key solution to the safe and stable operation of scraper conveyor is to ensure the accurate adjustment of tail chain tension and the safe locking of the scraper conveyor under the above conditions. The automatic adjustment and safety locking technology of scraper conveyor chain tension are studied.A chain tension automatic adjustment system for tail of scraper conveyor has been studied, which can automatically adjust scraper chain tension of scraper conveyor and can also be locked automatically. The system is applied in the coal mining process and the results show that the system can not only automatically adjust the tension of the chain and make it adapt to the load of scraper conveyor, but also accurately realize the automatic locking after the tension is completed. This system can help to improve the operational reliability of scraper conveyor obviously.

In order to meet the requirement of automatic and intelligent development of AFC, aiming at the problems such as complete manual operation, experience control of preload force and insufficient power when tightening chain are existed in hydraulic motor tight chain system of AFC at present,an automatic tight chain system was designed. By arranging electromagnetic clutch in the transmission device of scraper conveyor, the system can realize the controllable clutch between the hydraulic motor tension chain device and the transmission system；And the speed sensor and pressure sensor were arranged on the hydraulic motor to make the output of the tension chain force accurate and controllable.In order to adapt to the needs of actual working conditions, the hydraulic motor tension chain system should have the ability to drive the overload AFC in order to remove part of the overloaded coal. Around the above functions of hydraulic motor automatic tension chain system, the system construction, parameter setting and hydraulic motor selection were analyzed and discussed.

There are four kinds of fault of scraper conveyor’s chain, which are chain broken, scraper broken, loocked-rotor and chain jumping. In order to detect the fault timely and to ensure stable and reliable operation of scraper conveyor and the safety production in coal mine face, an on-line device, by which the four chain fault can be detected, is designed for chain fault monitoring of double side chain scraper conveyor.The sensor for scraper conveyor's chain fault is designed. The overall architecture of the flameproof?and?intrinsically?safe monitoring device is proposed, which have double MCU, human-machine?interface and Ethernet?interface. Reasonable selection of core components of the device is presented. Core circuit of the device composed of photoelectric isolation circuit, mininum system, pulse signal measuring circuit, etc. is designed. Pulse signal analysis logic is introduced to recognize the faults. Development of the on-line monitoring device can detect the fault of scraper conveyor’s chain timely and provide guarantee for both the life of workers along the convey and the safety production of coal mine.

In order to meet the needs of structural adjustment and transformation and upgrading of the coal industry and promote the safe and efficient mining of coal mines, coal mining enterprises urgently need to upgrade the equipment level through leasing. By expounding the development status and trends of China's leasing industry and manufacturing industry, the status quo of large-scale equipment leasing in the coal industry and the development of large-scale equipment leasing in coal mines are the general trend. Traditional equipment management has shortcomings such as high fixed asset investment, low equipment utilization rate, high inventory of parts, long purchase period, and difficulty in maintenance and maintenance. Large-scale equipment leasing mode has low investment in fixed assets, short cycle, high equipment utilization rate, repair and maintenance. Ok, update and timely. The large equipment leasing model can promote safe and efficient production of coal mines. Since 2018, Shangyuquan Coal Mine has started to lease large-scale equipment, which has improved the equipment level, promoted production intensification, safety and efficiency, and reduced costs. Large-scale equipment has achieved good safety, social and economic benefits in the use of the rental model in Shangyuquan Coal Mine.