Want to know: Where is Chengzihe Coal Mine in Xuzhou City?
this coal mine is located in chengzihe coal mine, Tongshan county, Jiangsu province, which is located in Liu Quan township, 22km north of Xuzhou city, on the south bank of Weishan lake. It belongs to Tongshan County Coal Company, and it was sold several times in the 199s when the benefits were particularly poor. Later, it was taken over by Xuzhou Local Coal Company, which later changed its name to Tianneng Coal Group, and later sold it to China Resources Group as a whole. Now it is also called China Resources Tianneng Xuzhou Coal and Electricity Company. The benefit is not good, the output is not high, and it is just barely surviving.
As for why Chengzihe Coal Mine was later renamed as Liu Quan Coal Mine, one reason is that it is located in Liu Quan Township, and the other reason is that on June 2th, 22, a gas explosion occurred in Chengzihe Coal Mine in Jixi, killing 124 people and shaking the whole country. For the sake of good luck, it was quickly renamed as Liu Quan Coal Mine.
Lessons and reflections on the "6.2" catastrophic gas accident in Chengzihe Coal Mine of Jixi Mining Group Company
At 9: 45 on June 2, 22, a catastrophic gas explosion accident occurred in the west second mining area of Chengzihe Coal Mine of Jixi Mining Group Company, killing 124 people and injuring 24 others, resulting in a direct loss of 9.84894 million yuan.
First, the main reason for the accident
Chengzihe Coal Mine is a high methane mine, with an absolute emission of CH4 of 41．75m3／/min, a relative emission of CH4 of 22.6m3/t and a coal dust explosion index of 33.5%-33.9%. KJ4 gas monitoring system has been put into use in this mine. There are 22 gas sensors and 19 gas cut-off probes installed in 17 heading faces of 3 coal faces underground. Underground gas drainage system without gas. The accident occurred in the West No.2 Mining Area, mainly mining coal in the 3B layer and the No.24 and No.25 layers. There are 145 fully mechanized mining face, 81 all-coal driving and the original 82 all-coal return air shutdown roadway (24 meters) in the 3B layer.
the gas explosion occurred at the place 146 meters away from the sliding door of the 3B-floor all-coal downhill air duct (the original 82 shutdown lane). This roadway is driven down the mountain along the 3B-layer full coal, and is constructed by drilling and blasting method, with bolt support and roadway section of 6.3 square meters. During tunneling at the beginning of the year, double local fans and double air ducts supplied air at the same time, the air supply volume was 36m3／/min, the CH4 concentration of roadway return air was .9%, and the absolute gas emission reached 3．24m3／/min. On January 2nd, there was a gas burning due to a local fan stopping the wind, workers sending electricity by mistake and cable blasting. At the end of January, the roadway was closed, and on May 24, after gas drainage, the roadway was unsealed, ready to withdraw the equipment. On June 16, the mine decided to change this roadway into a temporary water warehouse in the newly put into operation 145 fully mechanized mining face. By the time of the accident on June 2, the accumulated water in the roadway was 8 meters long and the all-coal roadway above the water surface was 16 meters long. Before the accident, a 28KW local fan was used to supply 16m3／/min air to this all-coal shutdown lane, and a 11KW local fan was used as a backup. A monitoring probe is set 15 meters down from the sliding door of the coal roadway, and the monitoring signal can be reflected to the monitoring room in the ventilation area. After the accident, the the State Council Technical Investigation Team conducted on-site investigation in the disaster area, investigated and obtained evidence from 35 insiders, and dissected and obtained evidence from the underground power supply system and four power supplies. It was confirmed that the automatic transfer line between the main and standby local fans at the scene was disconnected, the wind power lockout was short-circuited, and the gas and electricity lockout was not connected. After full investigation and technical appraisal, it is determined that the main causes of this accident are as follows:
1. Gas accumulation in coal roadway caused by local fan stopping. The workers in the outsourcing team mistakenly sent electricity, which caused the submersible pump switch (the bolt switch failed to explode) to generate arc sparks, causing gas explosion. In the process of explosion flame propagation, part of coal dust in transportation roadway and 145 coal mining face and the destroyed blind roadway sealed Nevas participated in the explosion. Increase that destructive power of explosion.
2. The security management of the outsourcing team is chaotic, and it is seriously managed by the package. 32 people were killed in the on-site outsourcing team in the disaster area. When the outsourcing team enters the well, there is no formal employment contract, no formal safety training, no effective safety management system, and there is no unified safety supervision and management for underground operations.
3. The management of sending and receiving electricity in the underground accident area is chaotic. The outsourcing team has no report or approval on power failure and power transmission. The outsourcing team has no full-time electrician, and the temporary workers who don't know the power supply knowledge often pick up the power at will, stop the power transmission at will, and the wind power and gas power atresia are short-circuited or dumped at will.
4. After the key gas heading face (all-coal roadway) was sealed and unsealed for reuse, reliable ventilation safety measures were not re-formulated and implemented. This coal roadway was designated as a key gas working face before the accident, and the methane concentration of return air was .7%, and the absolute amount of gas reached 1．12m3／/min. We should continue to manage according to the key gas working face and implement special ventilation safety measures such as "three pairs and two locks".
5. The investment in flameproof and safety protection equipment is not complete. On-the-spot investigation in the disaster area found that there were four temporary ventilation facilities in the production system of the 3B layer, and the quality was unqualified. No flame-proof facilities were installed at the crosscut between the 3B layer and the No.24 and No.25 coal layers. In the disaster area, two coal miners, three drivers and outsourcing workers did not wear self-rescuers, and the team leader did not bring portable gas alarm, which expanded the disaster scope and increased casualties.
6. The quality of electric tongs monitoring workers is low, and they have no certificates. The three mechanical and electrical maintenance workers of the contracting team did not understand how to connect wind power atresia and gas power atresia, and did not receive pre-job training. There is no full-time operator in the gas monitoring room, and I don't know the report of exceeding the limit. The monitoring system showed that the gas exceeded the limit for 4 minutes, and no one observed or reported it. The repairman and the microcomputer observe the gas monitoring records within one hour and ask him why he didn't report the gas overrun, saying that the post responsibility system is not stipulated.
Second, lessons and reflections from the accident
Chengzihe Coal Mine "6? The "2" catastrophic gas explosion accident fully exposed the serious loopholes in the safety management of underground production mining areas, especially in the aspects of employment management, power supply and gas monitoring management. The multi-faceted seriousness of the hidden dangers of accidents and "three violations" is really shocking! Through in-depth investigation, it also revealed the deep-seated root of the hidden dangers that caused the accident: there is a dead end in safety and measures are not implemented. Reflecting on this accident, the main lessons we should learn are as follows:
1. Why did the wind stop for 42 minutes in the 16-meter all-coal shutdown roadway? The accident occurred in the 24m stop lane (with water accumulated in the lower part of 8m) in the 3B floor of the West Second District, and the construction started in October 21. It was closed in February 22 and unsealed on May 24, 22. The equipment was ventilated and evacuated. Before the accident, the actual supply air volume was 16m3／/min, the return air gas concentration was .7%, and the absolute gas emission was 1．12m3／/min. This is still a key area that can not be ignored and a high gas source? According to the data stored in the main engine of the mine gas monitoring system, there is a monitoring probe 15 meters away from the door of the mine. The monitoring data of the probe show that the local fan of the mine stopped running at 9: 3, and the Nevas concentration of the mine rose rapidly, from 9: 3 to 9: 11; 9: 24; At 9: 42, the gas concentration reached 1.4%, 2.2% and 3.1% respectively. At 9: 45, the gas concentration at the probe position reached 3.51%, and the gas concentration at the explosion source position in the shutdown lane reached about 7.2%. According to experts' calculation, the roadway can accumulate 47．4m3 gas when the wind stops for 42 minutes, and the original accumulated gas amount is 7．6m3. The accumulated gas in the 16m long coal roadway with no wind can reach 54．1m3. If we can find it early and call the police in time to take effective remedial measures, this accident may still be avoidable? But after the accident site investigation, the underground gas monitoring system didn't work? The power failure alarm instrument didn't work? Security and tile inspection "posts, nets and sentries" didn't work! The monitoring operator and the underground tile inspector did not report to the mine dispatching and mine leaders, and missed the opportunity to remedy.
2. Why does the misfire switch generate an arc spark? There is no blasting fire source, mechanical collision, friction sparks from falling rocks and other smoking fire sources in the shutdown roadway where the accident occurred. The pin switch of submersible pump in the explosion source center of drainage roadway is in the state of virtual connection and explosion loss, the interlock between the local fan for air supply and the power switch of submersible pump is disconnected, and the gas electric lock is not connected. In this case, workers start the interlock switch and send electricity through the water pump switch, which is bound to produce sparks to detonate the arc? If so, the water pump power supply has realized gas and electricity locking. Although the Nevas accumulation in coal roadway exceeds the limit, the water pump latch switch can't send electricity. In fact, this accident can be avoided? If it is already known that the "two locking" of wind power and gas power will not work, but the gas should be checked before power transmission, and the tragedy will not happen as long as the gas concentration does not exceed 1% before power transmission? If the worker who mistakenly sends electricity is a professional who knows electricity and wind, check the gas before sending electricity. If the gas concentration is above 3%, please ask the ambulance team to discharge it, and if it is below 3%, the leader of the well area will direct the gas discharge. The tile inspector below 2% will supply air to exhaust gas first, and then send electricity when the gas concentration drops below 1%. Will this unprecedented mine disaster disappear? As we all know, there are hidden dangers of gas and spontaneous gas accumulation when the wind stops in mining roadway; There are problems in the operation and technical supervision of gas discharge measures of "grading, limiting and discharging" after inspection. If the post responsibilities were fulfilled in advance or such hidden dangers were completely eliminated in time, this extraordinarily serious gas explosion accident might have been avoided?
3. Why did the coal dust float in the sky participate in the gas explosion? The 3B coal seam at the accident site belongs to the coal seam with coal dust explosion, and the coal dust explosion index is 34.82%. After the accident, the field investigation by the rescue team and the expert group found that there were many typical corner-shaped high-temperature and overheated coal dust coking in the upper lane entrance, the leading single pillar, the fully mechanized support at the upper part of the working face and the entrance of the lower lane. Laboratory analysis of coal dust coke showed that the ash content of the dust sample increased from 24.87% before the accident to 47.92%, and the volatile content decreased from 25.9% before the accident to 17.65%, and the CO concentration in the upper corner and the lower corner of the coal mining face was 35ppm and 3ppm, which proved that coal dust not only participated in the explosion, but also increased the destructive power of the explosion. There was coal dust flying in the explosion, indicating that there must be dead corners and dust accumulation hidden dangers in the previous comprehensive dust prevention. It reflects that the daily underground dust prevention is weak, there is coal dust deposition on the fully mechanized pillar and belt transportation roadway, the dust prevention supervision is lax, there is no detection system for the excessive coal dust concentration, and there is no evaluation method for the effect of dust prevention measures.
4. Why is the safety management of outsourcing team so chaotic? The contract for the outsourcing team to enter the well is only a verbal agreement of the mine leader! The outsourcing team entered the mining area where the accident occurred and mixed with the mining team of this mine, so there was no unified and effective safety management. There is no unified and formal safety supervision for ventilation, power supply, maintenance and attendance when the outsourcing team enters the well to contract the working face. The underground power transmission, the wind and the three pairs of two locks are stopped at will, resulting in gas accumulation, which can not be completely dealt with as soon as possible. The lesson of oversight here must be carefully learned?
5. Why are the ventilation safety protection facilities incomplete? 18 meters between the 3B layer where the accident occurred and the No.24 layer coal affected by the accident, and no flame-proof facilities were installed in the stone gate between coal seams; There are four temporary ventilation facilities in the vicinity of 145 fully mechanized mining, especially all the personnel entering the well did not wear self-rescuers, and the team leader and electrical fitter did not wear portable gas alarms, which led to the weakening of disaster resistance and the expansion of disaster casualties. The safety debt exposed by the accident is the result of recent economic difficulties in coal mines. However, as long as the mine leaders pay attention to these small debts of monitoring instruments, they can be completely solved as soon as possible.
6, 64 How can workers in distress escape safely? After the gas explosion, because the whole ventilation system and facilities in the West Second Mining Area have been destroyed, five workers and one tile inspector of the 64 driving team heard a muffled sound, and then a lot of fly ash and black smoke rolled in. In the face of sudden disasters, panicked workers want to take risks to escape! However, tile inspector Zhang stopped them and guided them to retreat to the inner part of the working face, turned off the miner's lamp and took measures to save themselves and wait for help. After waiting for 3 minutes, the full wind pressure system gradually recovered, and the black smoke from the explosion gradually became scarce in the 64 driving roadway. The tile inspector led the workers to cover their mouths with wet towels and quickly evacuate the disaster area. Created a successful example of escape from danger. If there was no tile inspector at that time to guide the outsourced workers to withdraw from the working face to save themselves and avoid the peak of carbon monoxide temporarily, but ran around with black smoke, then everyone would be poisoned in the face of the disaster area environment with the concentration of CO as high as 35-4 ppm.
III. Preventive measures for similar accidents
Workers, cadres and technicians in coal mines must learn a lesson and sound the alarm bell; It is necessary to draw inferences from others, prevent the delay, and consciously and seriously check hidden dangers and plug loopholes. Pay equal attention to ventilation safety management, equipment and training; Adhere to the prevention and control of gas "machine governance, machine governance, people governance" simultaneously; Adhere to the idea of simultaneous investigation of the hidden dangers of ideological numbness and on-site accidents, make up your mind, concentrate your strength, and fight the tough battle of "pre-prevention, comprehensive management and control of the source" to eradicate gas.
1. Focus on prevention and control, and implement the "twelve-character" policy. Gas prevention and control in high gas coal seams and key gas working faces should be listed as the top priority of safety work. It is necessary to grasp the three fundamental links of "first pumping and then mining, monitoring and controlling, and determining production by wind", and take this as the three major points, and implement them item by item to realize the comprehensive gas control measures. The 3B coal seam in Chengzihe Coal Mine must be "pumped before mining".
2, relying on scientific and technological progress, improve the prevention and control equipment. The gas monitoring system must be installed in the high outburst mine, and the coverage of monitoring probes for gas and local fans and air door switches in the mining face should reach 1%; The putting-in-service rate of power-off instrument in mining face of low biogas mine should reach 1%; The integrity rate of underground monitoring power-off instruments and probes should reach 1%; The input rate of underground wind measurement, dust measurement, tile inspection, safety supervision instruments and self-help protective devices should also reach 1%. All coal seams in each mining area should explore the law of gas emission and formulate and implement perfect targeted measures.
3. Ensure that the main and local fans are always running, so as to realize sufficient mining air volume. The local fan in use underground should be powered by special power supply and equipped with conversion power supply, and underground coal mining must be ventilated by full wind pressure; Wind power and gas electricity locking must be implemented for the local fan in tunneling, and the automatic delay locking device of wind power and the remote monitoring technology of local fan stopping wind should be popularized. Any gas accumulation caused by the random stop of the main fan should be traced and dealt with according to the accident.
4, strict management of blind alley, eliminate the gas overrun accumulation. Mining construction is not allowed to leave an unsealed blind alley. The shutdown, closure and unsealing of driving roadway must be strictly implemented. The unsealing and reusing of blind roadways with one end must first detect gas, then discharge gas and restore the ventilation system. As a key gas working face, it must still be strictly supervised according to the key working face.
5, strict ventilation safety training, improve the technical quality of workers. Workers should be trained in the professional safety knowledge of "Mining Machine Express" in a formal and systematic way, focusing on safety laws and regulations, safety practical technology, self-rescue, mutual rescue and safe escape demonstration education for workers in major and various accidents and catastrophes; Organize gas and coal dust simulation explosion demonstration education, enhance the technical quality of underground workers to deal with major accidents, realize self-help, and fundamentally improve the mine disaster resistance.
6. contractors outside the mine who have not received safety training are not allowed to enter the well for construction.