At 20:20 on April 5, 2024, a coal and gas outburst accident occurred in Tangchong Coal Mine of Jinzhushan Mining Co., Ltd. of Hunan Coal Industry Group, resulting in 4 deaths and direct economic loss of 4.888 million yuan.
Recently, the National Bureau of Mine Safety Hunan Bureau website released the "4.5" Major Coal and Gas Outburst Accident Investigation Report of Tangchong Coal Mine of Jinzhushan Mining Co., Ltd. of Hunan Coal Industry Group.
Cause and nature of accident
（1） Direct cause of accident
Coal seam 5 is an outburst coal seam, and 21510 cut hole uphill is affected by the superposition of the concentrated stress of the coal pillar at the mining boundary of the overlying coal seam 3, the structural stress of the fault zone and the self weight stress, resulting in coal and gas outburst; In case of prominent omens, illegal command and risky operation lead to casualties.
（2） Nature of accident
After investigation, it was found that this was a production safety liability accident, and the accident was reported late after the accident occurred.
Main problems of relevant responsible units
1. Tangchong Coal Mine
(1) Conceal the working face. The 21510 cut hole uphill excavation working face was not marked on the mine excavation engineering plan, the T1 methane sensor and the return air flow T2 methane sensor installed on the working face were not connected and uploaded to the safety monitoring system, and the 21510 cut hole uphill excavation working face was not reported to Lengshuijiang Emergency Management Bureau as required.
(2) Command risky operations against rules. On April 4, the coal mine had obvious outburst omens during the prediction and forecast at the accident site. The coal mine did not conduct comprehensive analysis and verification in accordance with the requirements of the Detailed Rules for the Prevention and Control of Coal and Gas Outburst, did not take regional or local comprehensive outburst prevention measures, and still arranged for the replacement of supports in violation of regulations and other operations unrelated to the gas control project.
(3) Organize construction in violation of regulations. Without obtaining the commencement order, tunneling operation procedures and special design for outburst prevention without the approval of the company, the 21510 cut hole heading face construction was organized without authorization.
(4) No local outburst prevention measures were taken. From March 21 to April 3, 2024, the 21510 cut hole heading face was driven 72m up the mountain, violating the Detailed Rules for the Prevention and Control of Coal and Gas Outburst, without implementing the forecast and the excavation permit system; In violation of the provisions of 21510 Cut Hole Driving Operation Regulations, manual pickaxes were used to drop coal without one-time full face blasting.
(5) Technical management is disordered. The design of working procedures for 21510 cut up heading face shares the return air lane with 21512 coal mining face; The cut hole is arranged along the fault edge; Select obsolete wood support; The uphill driving operation was adopted, and no special measures were formulated to strengthen the support and reduce the empty roof distance of the roadway; The technical documents were not submitted to Jinzhushan Mining Company for approval as required.
(6) The safety management organization is not fully staffed. The head of the communication and prevention section is temporarily absent, and the temporary responsible person is not specified; The 21510 cut hole was not equipped with a full-time gas inspector as required during the tunneling up the hill.
(7) The implementation of relevant mine systems is not in place. There was no monthly special office meeting for outburst prevention, no special meeting for outburst prevention and early warning, and no daily analysis of mine ventilation and gas.
(8) The implementation of the dual prevention mechanism is not in place. The 21510 cut hole heading face is arranged along the fault, located in the structural stress concentration and fault fracture zone, which belongs to the prominent high-risk area and difficult roof management area. It was not included in the key working face during the risk study and judgment.
(9) The troubleshooting and treatment of hidden dangers are not in place. Since 2024, there has been no hidden trouble in the prevention and control of coal and gas outburst at 21510 cut up heading face.
(10) Safety education and training are not in place. Failing to implement and study the gas control management system such as the Collection of One Ventilation and Three Prevention Systems; The coal mine did not organize operators to conduct escape and rescue drills in case of outburst accidents after 21510 cut hole went up the mountain to resume construction.
2. Jinzhushan Mining Company
(1) Pay more attention to production than safety. The leaders of the company went to Tangchong Coal Mine for inspection, only asking about the output and the situation of the coal mining face, but not the situation of the driving face; The department leaders turned a blind eye to the illegal construction of the 21510 cut up heading face in Tangchong Coal Mine.
(2) The review is not strict. After receiving the special design for coal mine outburst prevention, the Ventilation Department did not organize the review and issue written review opinions; After returning, they did not put forward clear opinions, nor did they track and check the implementation. The Production Department did not supervise and inspect the formulation and review of 21510 hole cutting operation procedures.
(3) Poor supervision and inspection. There was no supervision and inspection on the implementation of the safety production system documents, and daily safety inspection did not find any illegal arrangement of the coal mine, unauthorized organization of construction, and failure to take outburst prevention measures. The deputy director of the production department went to the 21510 working face for inspection, and found no safety hazards such as inadequate regional prediction and forecasting, failure to implement the excavation permit system, and failure to upload sensor data to the monitoring system, and made a conclusion of acceptance.
(4) Stay in the mine and guard the vacancy. The technical director of the company in Tangchong Coal Mine went to the 21510 working face twice on March 22 and 29 for inspection and did not put forward any inspection opinions related to the 21510 working face. On April 4, after the Lianshao Administration Bureau issued the notice of stopping tunneling, it did not report the relevant situation to the company leaders and the Safety Supervision Department, nor did it take further follow-up measures.
3. Lianshao Administration Bureau
(1) The understanding of outburst prevention in Tangchong Coal Mine is not in place. Failing to focus on the outburst prevention work of Tangchong Coal Mine, and failing to check the implementation of the "four in one" outburst prevention measures of Tangchong Coal Mine as required; The risk study and judgment did not include the 21510 cut up working face in the key safety supervision front.
(2) The safety inspection of Tangchong Coal Mine was not carried out carefully. Failing to timely point out the failure to implement the "four in one" outburst prevention measures at the cut and climb working face; No problems were found, such as the cut up heading face was not shown above, and the methane sensor data was not uploaded.
(3) Major problems found are not reported in time. On April 4, the safety supervisor stationed at the mine found an outstanding omen at the working face and issued a notice of stopping working, but did not report to the leaders of Lianshao Administration Bureau.
Basic information of accident unit
1. Hunan Coal Industry Group Jinzhushan Mining Co., Ltd
Hunan Coal Industry Group Jinzhushan Mining Co., Ltd. (hereinafter referred to as Jinzhushan Mining Company), located in the urban area of Lengshuijiang City, was founded in 1951. It was merged from the original Jinzhushan Coal Mine and Lengshuijiang Coal Mine in March 2002 and is now a wholly-owned subsidiary of Hunan Coal Industry Co., Ltd. The company has three production mines, namely Tangchong Coal Mine, Tuzhu Coal Mine and Yipingdong Coal Mine.
2. Tangchong Coal Mine
Provincial state-owned coal mine, located at the junction of Sangzi Town, Xinhua County, Hunan Province, and Zhonglian Township, Lengshuijiang City, was founded in 1983 and put into production in 1987. It was originally identified as a high gas mine. After integration with Lanjiatian Coal Mine (coal and gas outburst mine) in June 2005, it was identified as a coal and gas outburst mine by Hunan Provincial Coal Administration Bureau, but the integration and technical transformation work was not completed, and the two mines were physically isolated in July 2016, It is still identified as a coal and gas outburst mine.
3. Lianshao Mining Area Work Safety Administration
Lianshao Mining Area Work Safety Supervision and Administration Bureau (hereinafter referred to as Lianshao Administration Bureau) is the safety supervision organization dispatched by Hunan Coal Industry Co., Ltd., which performs the main responsibility for safety supervision of the raw coal company under its jurisdiction.
Accident process
At 15:20 on April 5, Li Yongguang, the head of the mine, presided over the on duty shift meeting. After explaining the relevant safety issues, the on duty operators of the fourth excavation team were arranged to go up to ± 0 m track to clean up the debris and 21510 cut holes to replace the support. At the same time, it was clearly required that the fourth excavation team could not carry out excavation operations, but only repair and clean up.
At 15:40, Li Chuanwei, the on duty foreman of the fourth excavation team, organized a pre shift meeting and arranged Li Chuanwei and Furuitao to clear debris on the ± 0m track. Zhang Yingsheng (the site leader), Li Xiao'an, Zheng Dazhong and Deng Bihuan went to 21510 to cut the hole and go up the mountain to replace the support.
At 16:30, Li Yongguang, together with Zhang Yingsheng, Li Xiao'an, Zheng Dazhong and Deng Bihuan, arrived at the 21510 cut hole heading face at the same time. After the head-on inspection, Li Yongguang asked the on-site operators to continue to clean the floating coal in the roadway after replacing the support, and then left to the 21512 coal mining face to watch.
At 17:00, the tile inspector Li Huiqing went to the 21510 cut hole heading face to check the gas. At that time, the gas concentration was 0.24%. At that time, four people including Zhang Yingsheng were transporting supports. Li Huiqing left the working face after checking.
At 19:10, Li Huiqing arrived at the 21510 cut hole heading face again and checked the gas concentration of 0.24%. At that time, four people including Zhang Yingsheng were digging coal head-on. Li Huiqing left the working face after checking.
At 20:27, Li Yirong, the watchman of the control room, found that the T2 methane sensor of 21512 coal mining face gave an out of limit alarm through the safety monitoring system, with the maximum value of 1.89%.
According to the technical appraisal, the actual time of coal and gas outburst in the coal mine is 20:20 according to the accident site, the location distance of T2 methane sensor in 21512 coal mining face, and the mine wind speed, air volume and other data at that time.
Identification of accident responsibility and suggestions for handling the person responsible for the accident
Administrative punishment on 31 persons involved in violations of laws and regulations from Lianshao Administration Bureau of Hunan Coal Industry Group, Jinzhushan Mining Company, Tangchong Coal Mine, Lengshuijiang City and other units and relevant personnel shall be handed over to Hunan Bureau of the State Administration of Mine Safety and local emergency management departments for handling according to laws and regulations; If a disciplinary sanction is given, it shall be dealt with by the unit that has the authority to manage cadres in accordance with regulations and disciplines; If Party discipline punishment is given, the Party organization with management authority shall deal with it in accordance with regulations and disciplines; If a crime is suspected, the case shall be transferred to the public security organ for investigation.
