【 Weak current College 】 coal mine methane explosion causes and countermeasures

In coal mining, gas explosion, coal dust explosion, coal and gas, poisoning, asphyxia mine fires, flooding, roof caving, and other disasters occurred from time to time. In these accidents particularly in gas explosion caused the greatest loss from annual accident statistics, mine happens once killed 10 people or more serious accidents, mostly due to gas explosion, about catastrophic accidents account for about 70 percent of the total, to this end, the gas is known as the King of the coal mine disaster. Therefore, the analysis of gas explosion causes, to develop preventive measures, especially important.

1. analysis of the causes of gas explosion

1.1 gas explosion characteristics

According to many years of coal mine gas explosion in statistical analysis, you can find some of the features are as follows:

① gas explosion for big accident;

② accident occurred in coal mining and tunneling face;

③ gas explosion damage scope;

④ for spark ignition;

⑤ low gas gassy mines, mine are happening '

⑥ gas explosion occurred at the mine '

⑦ infrastructure, technological transformation of mine and mine gas explosion accidents.

1.2 accident reason analysis

Coal mine gas explosion occurred with many factors, but on the whole, the main and natural factors, security, technology, safety equipment, safety awareness and management level, and so on, the gas explosion accidents are often the result of interaction between the above factors.

1.2.1 the poor conditions of coal mining

China coal mine underground mining conditions are generally poor, according to statistics, 2000 national key State-owned mine coal in total 580 Department had gas grade identification, of which 160 gassy mines, low gas mine 298, coal and gas mine 122 Department; a spontaneous combustion, mine 372 accounted for 64 percent, coal dust explosion at the mine, 427 73.6%.

1.2.2 the existence of gas accumulation

Coal mine gas accumulation due to various reasons, but mainly for the ventilation system is not reasonable and local ventilation mismanagement is the main cause of gas accumulation. As of 2005, 34 extremely large gas explosion, 22 mainly due to the ventilation system air flow is not reasonable, there are many times series and short circuit, circulating air, resulting in inadequate air supply stations air flow, gas accumulation resulting from; there are 9 is mainly due to improper installation location for local fans, hairdryers, does not extend to air supply point or drop caused by insufficient wind point effective air flow, causing gas accumulation; 2 accident is mainly due to power outages caused by the wind stopped for gas accumulation; one is the blind alley of accumulation of gas was detonated.

1.2.3 detonate the presence of fire

Coal mine gas fire have detonated: blasting spark, electric spark, friction shock to electrostatic spark, spark, spontaneous, and so on. But shooting and electrical equipment produced by the spark is a gas explosion in the main source of fire. As of 2005, 34 extremely large gas explosion, 16 were produced by shooting sparks ignite; 15 accidents by electrical equipment and power supply cable of the ignition spark.

1.2.4 equipment, management does not implement the

Mine safety equipment configuration, after the "first take, the monitoring and control, to wind up production" policy has not been fully implemented. As of 2005, 41 extremely large gas accident, mine gas monitoring system is not installed or is not functioning correctly, although mine installed monitoring system, but because of the insufficient number of sensor, installed in the wrong place, the line is down, the monitor does not display the data, and so on, are unable to effectively play its proper role. Besides the large mine gas accident are not equipment gas drainage system or drainage system cannot effectively running, monitoring system could not function effectively. As Inner Mongolia wuhai city wuda Bayan competitions although an coking coal co., Ltd. installed gas well monitoring system, but its actual mining region is not caused by gas sensor, large gas accidents, killed 16 people.

1.2.5 management level low

Many accident analysis found that the illegal operation or mismanaged by the otherwise avoidable accident, but did not pay attention to, eventually causing large gas explosion. Therefore, the management level and worker safety awareness for coal mine production of long-term security is very important.

1.2.6 weak enterprise technology management

Some of the coal mining enterprises because of the mining method, causing unreasonable mine mining layout, ventilation system, in addition, job order preparation does not meet the actual, target, to serious safety problems.

2. control of gas explosion of technical measures

Gas explosion prevention can be divided into prevention of explosion and suppression of explosions. The prevention of explosions are: optimal ventilation network and ventilation system, prevention and treatment of gas accumulation, drainage, strengthening the monitoring of gas concentration and the fire source, prevent the emergence of the ignition source; suppression of explosive mainly uses the flameproof explosion suppression device will gas explosion limits within a certain range, thereby reducing casualties and casualty losses.

2.1 gas explosion prevention measures

2.1.1 coal mine methane drainage technology

1) China's State-owned coal-gas and gas outburst in total number of 46% mine. Gas suction is reducing mine gas emission, prevent gas explosion and prominent radical measures, but also the exploitation of gas energy, prevent the air environment of an important means. If the company belongs to Qidong mine in Northern use methane for generating considerable economic and social benefits.

2) to increase the gas pumpDrop rate, currently mainly need to resolve the long drill directional drilling technology, including the inclinometer, correction technologies; improve single low permeability seam of drainage rate; development drilling more powerful drill; improving and enhancing and extending technology, slag technology, makes the point technology and sealing technologies; development of new gas extraction technologies and equipment.

3) gas suction method with the coal seam gas drainage, adjacent layer drainage and goaf drainage; drainage process has bedding long holes, large diameter drilling, drilling, floors and roof rock drilling and other roadway. And developed in line with the powerful rig and related machines, such as the MK-long drill rigs and ZSM bedding powerful rig etc. In addition have developed various suction pump and related monitoring systems and instruments, etc., greatly improving the gas drainage capacity and drainage rate so that the security environment has been further improved.

4) using multiple branch pinnate applicable technologies to address the low permeability and gas governance to improve drainage.

5) mine gas governance should and coalbed methane production.

2.1.2 coal mine gas concentration and fire monitoring technology

Mine methane concentrations and sources of ignition in real-time automatic monitoring to prevent gas explosion is very important, when there is abnormal gas discovered fire, or immediate measures to prevent the explosion. We currently have developed as models of KJ90.KJ92.KJ94.KJ95.KJ73.KJ66 mine safety monitoring system, and various detection sensor, alarm and power meter. There are multiple mine installed mine safety integrated monitoring system, and provides the following features:

① mine environment and operating parameters of real-time monitoring;

② main fans online monitoring;

③ tunnel fire monitoring in real time;

④ mine drainage real-time monitoring;

⑤ real-time monitoring in blow pressure;

⑥ coal and gas monitoring in real time;

⑦ seam real-time monitoring of spontaneous combustion;

⑧ gas explosion or combustion monitoring;

⑨ mine network monitoring, and many other features.

Monitoring system installation dramatically increase coal mine safety management automation level, prevent many accidents.

2.1.3 underground fire prevention

On a coal mine explosion in spark, electric spark, friction shock to electrostatic spark, spark, spontaneous, and other sources of ignition are some of the appropriate control measures, in addition to explosives safety inspection, electrical explosion protection, inspection, inspection of friction Sparks, also need to prevent fire and gas accumulation in at the same locations, such as shooting test gas concentration, use locking, gas electric locking. Additionally strengthen the open fire management, strict fire system, eliminating the ignition source to detonate gas.

2.1.4 optimal ventilation network and ventilation system

Reasonable and reliable gas ventilation system to prevent accidents and the control of hazards of important measures to this end, gas control engineering and mining works, you must also design, construction, at the same time in advance.

2.2 flameproof measures

Mine explosion-proof device is the control of gas explosion in the last barrier, when gas explosion occurred, depending on the pre-set devices can prevent the propagation of explosions, limit the spread of flame, mainly passive flameproof shed and explosion suppression device automatically.

1) passive flameproof shed. Flameproof rock powder shed, flameproof sink booth and flameproof water bag shed because of low cost, easy installation, and therefore widely used, including explosion-proof water bag for the tent of the most widely used. The current development of XGS-type and explosion proof canopy, KYG type has a good adaptability, install, dismantle and move easily.

2) auto-explosion suppression device. Use pressure or temperature sensors, in the explosion occurred when detecting explosive wave, promptly pre-positioned water, flour, such as spraying to roadway N2.CO2, thus inhibiting the explosion flame propagation purposes. If ZGB-Y-explosion-proof device adopts high pressure nitrogen gas ejector long agent, can be explosive limit in distance of explosive source within 40-60m; YBW-1-power trigger type explosion suppression device, suitable for installation in explosive source 20-45m of roadway; ZYB-S-explosion suppression of gas-producing device adopts the principle of gas production in real time, when the sensor receives the combustion or explosion flame, fire gas generator to quickly produce high pressure gas spray long agent, inhibiting flame propagation.

3. concluding remarks

Gas explosion prevention and control of coal mine safety work is a systems engineering, in addition to perfect and reliable safety equipment and to take effective measures to enhance the safety management and safety, employee security awareness training. Only security first, conscientiously implement the gas treatment of "twelve-character" principle, improve the rules and regulations, reasonable and increase the safety input, gas explosion and other disasters can significantly reduce the security situation in the coal mine to be essentially improved.