I. Coal mine gas prevention and control policy

As one of the five major disasters in coal mines, the previous national coal industry management departments have attached great importance to the prevention and control of gas. In particular, in the past decade or so, the prevention and control of gas as a top priority for coal mine safety production has been carried out, and many effective rules and regulations have been formulated. And supporting measures. The "Provisions on the Prevention of Major Gas and Coal Dust Accidents in State-owned Coal Mines" promulgated by the former Ministry of Coal in June 1993 proposed that the "three specializations and two lockouts" measures must be implemented for the high gassy tunneling face, and the mining and mining faces with dangerous coal and gas It is necessary to implement the "four-in-one" comprehensive anti-burst measures, and propose a nine-character policy of "multi-drilling, strict sealing, and comprehensive pumping" for gas drainage mines. In September 1994, in the form of a ministerial order, the "three ten" regulations for the prevention of major gas accidents in state-owned, local, and township coal mines were reaffirmed. In June 1996, the former Ministry of Coal held a special meeting on the prevention and control of gas on-site in Yangquan and Mining Bureau of Shanxi Province, which comprehensively promoted the three systems of sound ventilation, drainage and monitoring of Yangquan Bureau, insisting on first pumping and mining, and wind production. experience of. At the same time, combined with the "6.23" accident that occurred in the Huainan Bureau in the past, it was decided to build a gas control demonstration project in Huainan, insisting on first pumping and mining. In April 1997, the former Ministry of Coal specifically issued the “Code for Management of Mine Gas Drainage”. In January 1998, the No. 1 document issued by the former Ministry of Coal was also aimed at preventing and controlling gas disasters, and put forward the requirements of “six inaccuracies. According to the actual situation of coal mine safety production in China, we have carefully summarized the experience and lessons learned from coal mine gas control work. On the basis of this, the National Coal Mine Safety Supervision Bureau put forward the 12-character policy of “first pumping, mining monitoring, monitoring and control, and wind production”.

2. Research on improving the comprehensive safety and key technologies of coal mine safety status

“Research on Comprehensive Improvement of Coal Mine Safety Status and Key Technologies” is a national key scientific and technological project of the “Ninth Five-Year Plan”. The project has fully utilized the overall advantages of coal industry research institutes and coal mines in demonstration mines, with Pingdingshan Coal Industry (Group) The combination of limited liability company, Yangquan Coal Industry (Group) Co., Ltd., Coal Science Research Institute, China University of Mining and Technology, and other 16 production, research and research units has solved many of the safe production of coal mines through nearly five years of concentrated research. Key technologies and common technologies have enabled the overall comprehensive capability of mine disaster prevention and mitigation in China to be further improved on the basis of the “Eighth Five-Year Plan”, and the demonstration project for gas disaster comprehensive treatment in Pingdingshan mining area and gas drainage and utilization in Yangquan mining area have been completed. Test base. According to incomplete statistics, the project has achieved direct economic benefits of 134.3 million yuan and indirect economic benefits of 612.4 million yuan during research and implementation. In terms of gas prediction, China has studied the gas desorption and influencing factors of geological prospecting boreholes, and established a unified and relatively perfect coal seam gas content and mine gas emission prediction method, which has realized the determination of gas content and the amount of gushing. The computerized, automated and standardized geological mapping of mine gas has a prediction accuracy of 80%-85%.

3. Coal and gas outburst prevention and control technology

China's anti-burst technology has experienced safety protection, prevention and control technology measures and comprehensive prevention and control stages. The "Detailed Rules for Prevention of Coal and Gas Outburst" formulated and promulgated in 1988, summed up China's comprehensive anti-burst technology as the "four in one" of forecasting, anti-burst measures, effect testing and safety protection measures, after the "eight five" and "nine" During the period of the five-year period, China’s anti-burst technology has reached the world's leading level.

(1) Comprehensive anti-burst technology. In the aspect of comprehensive anti-burst, the "four-in-one" comprehensive anti-burst technology consisting of coal and gas outburst danger prediction, prevention and control measures, anti-burst effect inspection and safety protection was established. Outburst risk prediction technology consisting of gas geostatistics method, comprehensive index method, geological index method, and geophysical method, and the work surface consisting of index method, acoustic emission method, electromagnetic radiation method, gas emission dynamic method, etc. The predictive technology has formed a technical system for predicting the risk of coal and gas outburst with Chinese characteristics. Studies highlight the risk of real-time monitoring technology to improve the large area of pre-pumping gas, construction technology for regional mining outburst prevention technology measures the protective layer to improve the pressure relief hole large diameter, with metal frame, high pressure water jet reaming The technical level of stone door anti-burst measures such as gas emission, discharge drilling and gas emission; promotion and application of advanced drilling (including large-diameter drilling), pressure relief gas, deep hole loose blasting gas, hydraulic punching, drilling and integration Technical and anti-extrusion measures for integrated face-lifting technology; research on integrated anti-burst technology for excavation face, non-contact detection of geological radar and electromagnetic radiation technology for frontal construction and prominent danger; perfect for vibration and shooting Distance protection measures such as shooting. And developed BQT-E type coal seam electromagnetic wave fluoroscopy system, KJ54 monitoring system, QFZ-22 portable anti- drilling rig , KBD5 mine intrinsically safe coal and gas outburst (impact rock pressure) electromagnetic radiation monitor, QFZ-22 The type of anti- drilling rig integrates the functions of powerful drilling and prevention of card drilling, and solves the problem that the existing anti-burst measures are not matched with the drilling rig. It is an ideal drilling rig for implementing anti-burst technology measures. The rig has been promoted and applied in more than 60 stations in Pingdingshan, Huainan, Hancheng, Weibei, Songzao and Hebi.

(2) regional coal and gas outburst prevention technology. With the popularization and application of top coal caving technology, regional coal and gas outburst prevention technology more and more attention. Huainan Mining Group mines belong to the mining of seam group, but most of the coal seam has a prominent danger, for testing on multiple mining protective layer, a protective layer at a distance, along the length seam drilling strengthen regional prevention and control of coal seam gas pre-pumping and gas technology. In Xinzhuangzi mine, leading mining upper B8 slot coal and mining B7b, B7a coal, to achieve outstanding risk of lower B6 slots (from B7a seam about 12m) and B4 coal seam (about 40m from the B6 tank) to eliminate prominent dangerous Objective; Panyi and Pansan mines test the exploitation of B11 (thickness about 1.8m) coal seam to achieve the purpose of eliminating the prominent danger of C13 coal in the upper distance of 70m or more; Xie's second mine test, long borehole in the coal seam, strengthening pre-extracted coal seam gas Eliminate the obvious danger and achieve good results. Pan Yi and Pan San Mine are conducting a top coal mining test on the C13 tank in the protected area. No signs of gas power have been found; the test surface of Xie Er Mine has been fully safely harvested using the top coal mining technology. This shows that, for different situations, different regional prevention and control technical measures can be adopted to eliminate the prominent risk of coal seams and achieve the purpose of safely recovering coal caving. However, when using protective layer measures, the gas control and protected layer of the first mining layer Gas drainage must be given high priority. When adopting the long-hole drilling to strengthen the pre-extraction gas measures, the prominent hazard prediction and pre-extraction process of each block area and the evaluation of the effect after pre-extraction must be given high priority.

(3) Prediction and prediction technology for coal and gas outburst danger. According to "Coal Mine Safety Regulations" provides a highlight of mine That happened as coal and gas outburst, had prominent seam that is scheduled to occur prominent seam. However, for new mines, coal seams have not been mined during mine design. At this time, the risk of mine gas outburst is mainly determined by the prediction of the risk of coal seams. If the coal seams mined in the mine are predicted to have significant hazards, they should also be identified as potentially dangerous mines.

The outburst risk prediction of coal seams in China is mainly based on geological exploration data. At present, based on geological structures, coal seam occurrence conditions, coal seam structure measured by exploration core, gas pressure and gas content, reference to adjacent mines or similar mines Statistical and analogical analysis of data reflecting outstanding hazards to predict the outstanding risks of coal seams. The main predictors are coal seam firmness coefficient, gas pressure, gas content, structural characteristics and distribution. Coal seams with f≥0.5, gas pressure not greater than 0.74 MPa and gas content not greater than 10 m/t generally do not have outstanding hazard unless significant changes occur in the structural failure zone due to relevant indicators. It should be pointed out that according to the research in recent years, the gas pressure and content measured during the geological survey are generally low. Therefore, in the data analysis, the possible error of the measured data should be considered. When the mining project enters the coal seam, it should be carried out on site. The relevant parameters are determined and verified.

For the prominent dangerous coal seams, the outstanding dangers of each mining area can also be predicted according to the above methods and indicators, but the measuring points should be encrypted, the greater the density of measuring points, the higher the prediction accuracy, in addition, the protruding areas should be highlighted. The point distribution law is used for analogy and statistical analysis to improve prediction accuracy. In recent years, the radio fluoroscopy method has been combined with the gas emission from the mining face, the dynamic characteristics of the mining face, and the distribution characteristics and laws of the predicted risk indicators of the mining face to comprehensively analyze and predict, which can predict the outstanding danger of smaller blocks. The prediction accuracy can meet the requirements of safe production.

For the mining face in the dangerous area, the dynamic index of AE acoustic emission and gas emission is studied experimentally, and the real-time tracking and prediction technology for the prominent danger of coal and rock mass around the mining face is tested. Experiments show that the coal rock mass will produce significant micro-damage sound when the load reaches 40%-60% of the ultimate load. By monitoring the micro-damage sound (AE activity) in the coal rock mass, the mechanical dynamics of the coal rock mass can be predicted in advance; By monitoring the dynamic changes of gas emission in the mining space, it is possible to predict the gas emission abnormality caused by the mechanical dynamics in the coal rock; the mathematical analysis and comprehensive analysis of the two aspects of information, combined with a large number of actual monitoring data and dynamic visualization characteristics Knowledge base is used to realize real-time tracking and prediction of the prominent danger of coal and rock mass around the mining face. Experiments in Nantong Coal Mine, Pingdingshan No.12 Mine and Furong Baiyu Mine show that this technology has a good application prospect.

The prediction of coal-rock dynamic phenomena by electromagnetic radiation is another new research result after the acoustic emission monitoring method. During the "Ninth Five-Year Plan" period, the electromagnetic radiation method jointly developed by Pingmei (Group) Co., Ltd. and China University of Mining and Technology has predicted the outburst technology and portable equipment. The technology has filled the domestic gap and realized portable non-contact continuous. 24-hour continuous forecasting.

4. Gas drainage technology

Gas drainage is one of the most effective measures to control gas disasters. According to the characteristics of different mining areas, China's coal mines have formed this layer, adjacent layers, through layers and goafs during the “Eighth Five-Year Plan” and “Ninth Five-Year Plan” period. A variety of gas drainage methods. The method and equipment for advanced gas drainage in the fully mechanized mining face were studied. The test succeeded in the continuous horizontal drainage of 200-500m rock horizontal drainage, coal seam level (250m) long borehole and pre-crack control blasting enhanced drainage layer. The comprehensive drainage technology of gas, etc., will increase the gas drainage rate of the working face by 20%.

(1) Long hole drilling technology. The key technology for gas drainage in the bedding layer is the hole-forming technology of the long hole in the bedding layer. When the coal seam (especially the protruding coal seam) is drilled in the coal seam, the sneezing L and the stuck drill are serious, and the hole penetration depth is often only 40. 70m, can not meet the depth of need for gas drainage in the face of coal mining face. To this end, during the "Ninth Five-Year Plan" period, the long borehole construction technology and equipment combined with the pressure slagging process, combined drilling tools and powerful drilling rig (ZSM-250 type bedding layer rig) were studied, which greatly improved the drilling depth. Up to 100m, the deepest reaches 239m. The key to the pressure slagging process is to determine reasonable wind pressure and air volume. In order to use the compressed air to discharge the cuttings smoothly, the wind speed of the slag discharged in the borehole is usually required to reach 20m/s or more. Under the condition that the compressed air passes through the broken area, the wind pressure and air volume that meet the slag wind speed requirements are mainly Depends on the depth of the hole. The main function of the combination drilling tool is to improve the orientation accuracy of the drilling hole, while also reducing the chance of collapse and other large deformation of the drilling hole. The purpose of the powerful drilling rig is to increase the drilling capacity. The ZSM-250 powerful drilling rig has a diameter of 63mm. It can meet the requirements of 250m of protruding soft coal seam with the wind slag and combination drilling tools. The complete set of technology and equipment was tested in the underground of Qiquan Coal Mine of Furong Mining Bureau of Sichuan Province. The depth of the bedding drilling layer reached 239.6m, and the gas pre-pumping rate reached 32%. Compared with the mesh drilling, it can save The cost per ton of coal is 4.3 to 6.2 yuan. It not only protects coal mine safety, but also saves safety investment and reduces production costs. At present, this set of technology and equipment is being promoted and applied in the offices of Furong, Songzao, Fengcheng and Huainan, and has achieved good results.

(2) Long horizontal drilling technology for rock formations. The main purpose of long horizontal borehole drilling is to pump gas from the goaf and adjacent layers. Many coal mines in China originally used roof roadways to meet this requirement. If drilling is used instead of roadway, it will save a lot of investment. To this end, the theory of moving deformation of overlying strata in the stope is studied. Based on this, a reasonable layout and layout of the drill collar L are determined. Combined with the development of the MK-6 and 7 drilling rigs, the test has a successful hole depth of 500m or more. slate horizontal top layer and the layer adjacent to the long drilling plumb gob gas technology, the maximum amount of gas withdrawn 23.92m3 / min at No.5 single hole, the hole Nevas concentration up to 90%, the average amount of gas withdrawn hole 19m3 /rain, the average concentration of 60%, the effect is quite significant. The technology is used to drill the coal seam in the Jinchengsi River Mine (coal layer, value above 1), and the hole depth is more than 500m, which provides a reliable means for the development of coalbed methane.

(3) Long borehole pre-crack control blasting technology. The technology is to control the pre-splitting blasting of the coal seam, forcing the coal body to produce cracks to release stress and gas, so as to improve the permeability of the coal seam and prevent and control. In order to crack the coal seam during blasting without destroying the roof, special explosive formulations and blasting processes were studied. The test shows that the low-power explosives studied have the characteristics of slow detonation speed, low explosion peak and long acting time, and have good cracking effect on coal seams; the research of pressurized air jet charge, double detonator detonation double detonating cord, The double-detonating cord blasting three-stage coal mine allows the use of solid (powdered) emulsion explosives, and the long borehole controlled blasting technology with radial and axial uncoupled charge is effective, safe and reliable. The technology was carried out in Pingdingshan and Yangquan. In the experimental study, controlled blasting with a hole depth of about 70m was realized in Pingdingshan No.12 Mine.

(4) Hydraulic reaming technology. The larger the aperture, the larger the exposed area of ​​the drilled coal wall, the more favorable the stress release and gas emission. The single-diameter drilling construction faces serious boring, difficulty in slagging, short hole length and geometrical increase of rig load. And many other technical issues. The hydraulic reaming is to first drill a small-aperture borehole with a drill, and then use a high-pressure water jet that can spray a high-pressure water jet and rotate itself to rotate the coal body around the borehole. The motion creates a radially continuous reaming of the entire borehole. As the diameter of the borehole expands, the exposed area of ​​the coal seam increases, more coal is discharged, and the coal seam pressure relief range is further increased, which has a significant effect on increasing the amount of single-draw L-discharge (discharge) of the borehole. In the Zhongliangshan North Mine, the amount of gas drainage increased by 0.6 to 1.0 times after reaming; in the Songzao Mining Bureau, the gas drainage volume increased by more than one time after reaming, and the effect was very obvious.

(5) Gas drainage technology in goaf. Closed intubation and ground drilling and drainage are mainly adopted for goaf, but for coal seams with natural fire hazard, fire sign gas or temperature monitoring should be strengthened. At present, monitoring of fire mark gas and automatic control and regulation of drainage are being developed. Negative pressure and flow devices solve the contradiction between gas drainage and spontaneous combustion.

The extraction of the goaf in the mining face is mainly carried out by means of buried pipe drainage, closed drainage of the goaf by open cut-off side, drilling of the ground, roof and floor. Aiming at the characteristics of low gas concentration in the goaf, the CJK automatic pumping switch was developed. The principle is as follows: the gas concentration of the pumping and discharging pipeline, the gas concentration of the mine gas drainage system and the environmental gas concentration of the discharge section are monitored, so that the concentration of the pumping point or the system concentration in the low concentration pumping is not lower than one. When the value is set, the pumping system performs the pumping. When both values ​​are lower than the set value, it will automatically switch to the ejector ejector ejector state, which will be ventilated and diluted by the ejector to the discharge section; when the environmental concentration of the discharge exceeds the limit, the discharge will be automatically stopped. Under the condition that the gas concentration of the system is not lower than the set value and the safety is ensured, the pumping point gas is subjected to low concentration enhanced pumping. The device has been applied in the gas-enhanced pumping of open goaf in the initial mining period of the fully mechanized caving face of the Yangquan Coal Industry Group. The effect is very obvious.

5. Gas coal dust explosion prevention technology

At present, gas dust explosion is the most serious accident in China's coal mines. To this end, China has established a large-scale actual scale simulation roadway and explosion test base, carried out various dust explosion mechanism, characteristics and anti-explosion test measures, based on the test of coal dust-like explosion characteristics of major coalfields in China. The research on the explosion characteristics under the condition of coexistence of gas and coal dust mainly discusses the problem of gas dust from the mining machinery cutting friction spark ignition and detonation, and puts forward the comprehensive measures to prevent the cutting friction spark detonation.

In order to solve the gas explosion accident caused by the accumulation of gas at the corner of the working face, on the basis of studying the law of the gas emission from the corner, the high-strength of the fan blade is adopted in the aspect of the non-sparking fan on the gas and the matching equipment. Anti-static flame-retardant plastic processing, so that no friction spark is generated between the rotating part and the outer casing; the fan is driven by the electric motor, and the motor is completely isolated from the extracted air flow to avoid the spark of the motor igniting the high gas flow. The fan population is equipped with a gas concentration monitoring sensor and an automatic air conditioning device to ensure that the gas concentration in the air cylinder does not exceed the specified value. Experimental studies have shown that the use of the device to treat the upper corner gas has a higher safety performance.

In the research, the performance of the passive explosion-proof water tank and water bag, the hanging process and the arrangement method were further improved. The XGS type explosion-proof water shed can also isolate the spread of the weak explosion and expand the effective range of the explosion-proof (20~24m from the explosion source). ) and easy to install and move. BJK-S automatic anti-explosion system can realize continuous monitoring of gas, coal dust concentration and sedimentary coal dust intensity in remote mining face or explosion hazardous area, over-limit alarm and control of power failure of working equipment; , weak explosions, etc. are extinguished on the spot, effectively controlling the gas and coal dust explosion. The YBW type power-free trigger type explosion-proof device developed in recent years uses the photoelectric detonating blasting to spray water quality anti-explosive agent. The optimal water mist formation time is less than 150ms, the water mist exists for more than 500ms, and has good fogging performance and daily life. The maintenance workload is small, and the installation and application are convenient.

Single Housing Pressure Filter

SDDF series filters consist of a filter head with a screw-in filter bowl. 1-piece filter bowl for size 660 and below; 2-piece filter bowl for size 990 and above. Standard filters are without bypass valve.

Material

SDDF series

Filter head: nodular cast iron Filter bowl: carbon steel

Seals:NBR

Special type

-With bypass valve

-Oil drain screw up to SDDF280

-Seals in FPM

Accessories

-Visual and (or) electrical

clogging indicator,clogging indicators should be fixed with corresponding torque values. (See Spare parts and maintenance list)

-Flange connection

-SAE-flange connection

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