Long Mei Jixi Mining Co., Ltd., Heilongjiang Province Didao Hesheng Coal Mine Shaft
"6.5" Large Coal and Gas Outburst Accident Case
On June 5th, 20021year, a major coal and gas outburst accident occurred in the shaft of Didao Hesheng Coal Mine of Jixi Mining Co., Ltd., Long Mei, Heilongjiang Province (hereinafter referred to as Didao Shaft), with 793.8 tons of coal outburst and about 10200 cubic meters of gas gushing out, causing eight miners to be trapped. After full rescue, all the trapped miners were rescued.
First, the basic situation of the accident unit
Didaojing is a state-owned key coal mine, which belongs to Jixi Mining Co., Ltd., Long Mei, Heilongjiang Province, with an approved production capacity of 300,000 tons/year. Coal and gas stand out in this mine.
The accident occurred in the preparation roadway of No.28 coal seam in the third section of the fifth mining area of the mine. The roadway is 4.2 meters wide, 2.5 meters high and 600 meters long. The roadway is supported by bolt and anchor cable. Before the accident, the roadway has been completed, and coal seam gas outburst prevention measures have been taken in the pre-pumping mining area. 203 drilling holes were designed and constructed, and the 94th drilling hole was under construction at the time of the accident.
Second, the direct cause of the accident
During the construction of No.94 bedding gas drainage drilling hole in No.28 coal seam mining preparation roadway in the third section of No.5 mining area of this mine, the surrounding coal body collapsed due to repeated drilling, which led to the enlargement of the diameter of the drilling hole, the loss of the protection function of the safety barrier, and the coal and gas outburst in the fourth drilling process.
Third, the main problems of accident exposure
1. Gas drainage is not in place. In the construction of bedding drilling, there are many holes with air holes. Before the accident, the gas concentration in the gas drainage pipeline increased from 5% to 10%, but the reasons were not found out and targeted measures were taken. According to the characteristics and conditions of coal seam, the sensitive index and critical value of working face prediction have not been determined by experiments, and the gas drainage effect test is unscientific.
2. The site safety management is chaotic. After dynamic phenomenon occurs in drilling construction, operators are illegally arranged to work at the threatened working face at the same time, and the drill pipe is illegally taken out of the hole to deal with sticking.
The lessons of the accident are not profound. The lessons of the 2018 "4 4" outburst accident in this mine are not profound (5 people were killed and 5 people were injured), and insufficient attention was paid to the bedding drilling construction. There are 16 bedding boreholes in the third section of No.5 mining area that fail to meet the design length requirements, and 97% of the boreholes constructed in May fail to meet the design requirements. Safety risk identification and assessment were not carried out in an all-round way, and the implementation of coal seam gas outburst prevention measures and the construction of outburst coal seam drilling were not listed as the key investigation contents as required, and the key investigation was replaced by routine inspection.
4. The mining connection is out of balance. The gas disaster control project is ahead and behind, which leads to insufficient coal mining. From mid-April of 202 1 year to the time of the accident, there was no coal mining face under the mine.
5. The accident was reported late. The accident occurred at 12: 00, and was not reported to the resident coal mine safety supervision sub-bureau until 16: 58.
6. The supervision and management of the superior company is not in place. Jixi Mining Company failed to guide, supervise and inspect the safety production business of Didao Vertical Shaft. Did not grasp the degree of disaster, drilling construction, site management, etc. Inspect the drip wells in time, and carry out detailed daily inspections and major investigations; Long Mei Group failed to supervise Jixi Mining Company's implementation of superior work safety deployment, and neglected to supervise Jixi Mining Company and Didaojing management personnel for failing to perform their duties correctly.