Cause analysis and prevention of gas accident in a

2022-08-21
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Cause analysis and prevention of gas accidents in a coal mine

a group company has 9 production mines. Among them, the thermoplastic films produced by Hexi, Shuangliu and kesichuang are used to produce SI2 seats. The three mines in Zhongxing are high gas mines, and Xinyang, Xinyu, Xinliu, Hedong, Shuguang and Zijin are low gas mines; The spontaneous combustion tendency of coal seams, Xinyu, Xinliu, Shuangliu and Hedong are class I, Xinyang, Zijin are class II, Hexi, Zhongxing and Shuguang are class III. According to the statistics of gas accidents in the company from 1956 to 2008, there were 11 cases and 53 deaths, accounting for 2.1% and 9.5% of the total number of accidents respectively. There are many kinds of material experiments conducted by actual users. From 1984 to 2008, there was no major gas accident for 25 consecutive years. However, its number is the fifth and the number is the third. It indicates that the frequency of occurrence is infrequent, but the harm is very serious

1 gas accident of the group company

1.1 gas accumulation (1) melt index statistics show that the main reason for gas accumulation is no wind and no circulating air. The main accumulation areas are the driving face, blind roadway, coal seam and goaf

2 gas accident prevention

2.1 prevent gas accumulation in the mine

2.1.1 strengthen ventilation management, and require the mine to have a safe, reliable, independent ventilation system with reasonable wind direction and stable air volume

2.1.2 deal with the accumulated gas in time, and adhere to the principle of "prevention first, treatment second". ① Close blind roadways and tunnels that have not been used for a long time; ② The unsealed blind tunnel area is provided with air plate and air simple bifurcation; ③ The air shall not be stopped on the temporarily suspended working face; ④ The mechanical mining face and unit shall be equipped with hydraulic injection and annular pressure air injection and supply equipment

2.1.3 for tunnels with large amount of gas accumulation, do not start the fan instantly, and formulate safe drainage methods

2.1.4 strictly implement the regulations, and actively establish a gas monitoring and detection system when necessary

2.1.5 separate source gas treatment and drainage. If the gas in the heading face exceeds 3m3/min and the gas in the mining face exceeds 5M3/min, the gas drainage method should be adopted

the 306 working face of Shuangliu coal mine belongs to the 3#+4# coal seam at the top of the lower Permian Shanxi formation, with a total thickness of 3.6~3.8m, with an average of 3.6m. The coal seams in this area are stable and complex in structure, with about three black mudstone gangue layers, and the coal seam dip angle is 0~14., Average 6O

at the right side of the forward direction of 306 haulage roadway and the left side of the forward direction of 306 tail roadway, construction boreholes are drilled for extraction. The boreholes are arranged inward (along the coal seam tendency) from the stoping line of the working face in turn. The boreholes are gradually constructed with the forward excavation of the working face, and the distance between the head-on of the working face and the adjacent boreholes shall not exceed 50m. The drilling spacing is 6m, and the drilling opening diameter is d129mm. After drilling 8m, replace with 89mm drill, with a hole diameter of 91mm. See Table 1 and 2 for the parameters of the first five boreholes of 306 haulage roadway and tail roadway

the permanent gas extraction system on the ground is used for extraction. The system consists of two 2bec52 water ring vacuum pumps and their supporting facilities. The laying of the extraction pipeline in 306 haulage tunnel is: ground extraction pump → pumping and drainage borehole → lower hole of borehole → centralized air return → South air return tunnel → third mining air return tunnel → 306 return air combined tunnel → 306 tail combined tunnel → 306 haulage tunnel. The laying of the extraction pipeline in 306 tail roadway is: ground extraction pump → extraction and drainage drilling → lower hole of drilling → centralized air return → South air return roadway → third mining air return roadway → 306 return air combined roadway → 306 tail roadway. A d219mm glass fiber reinforced plastic pipe is laid in 306 haulage roadway and tail roadway respectively, and the pipelines of haulage roadway and tail roadway are laid along the left side of the heading direction of the roadway, and connected with the d426mm main pipeline of the third mining return air roadway. When the static pressure is greater than 30KPa, the air leakage per kilometer is not greater than 3m3/min

two 2bec52 water ring vacuum pumps are used for pumping equipment; Motor model yyk, power 250KW; Three sgz- Ⅲ B and 300 drilling rigs are selected

d426mm glass fiber reinforced plastic pipe is selected as the main extraction pipe, 203mm glass fiber reinforced plastic pipe 1060m is selected as the extraction pipeline of 306 tail roadway, and 203mm glass fiber reinforced plastic pipe 700m is selected as the extraction pipeline of 306 tail roadway, and the pipeline should be gradually extended as the working face advances

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