When mining coal seam groups with the danger of coal and gas outburst, pre-mining coal seams with no prominent danger or less risk, depressurize the coal seam with outstanding danger, and release a large amount of gas, thereby weakening or losing the danger of coal and gas outburst . This pre-mined coal seam is called a protective layer, and the coal seam that is relieved of the danger of coal and gas outburst is called a protected layer, as shown. Mining protective layer L—protective layer; 2—protected layer; 3—roadway 1) Leading the hole. In front of the coal roadway face, drill holes with a diameter of 75-300mm, discharge gas, and form a pressure relief belt around the hole to prevent protrusion. Generally, the drilling depth is 15-20m. The advanced drilling is often used when the coal seam is thick, stable, coal is soft, and the gas permeability is good. However, when drilling, it is prone to pinching, boring, and even protruding inside the hole. 2) Hydraulic punching. Prior to the mining work, high-pressure water jets were used to punch out a number of larger diameter holes in coal seams with prominent hazards (or Shimen uncovering coal). A large amount of gas and a certain amount of coal can be discharged during the punching process, thereby forming a partial pressure relief zone in the coal body, in which the protrusion can be prevented. Hydraulic punching is often used in Shimen coal uncovering, coal seam roadway excavation and mining face. When Shimen uncovers coal, hydraulic punching should retain 3 to 5 m of safety lithology in front of the working face. 3) Vibratory shooting. A special shot method used to induce protrusion. When the wells and roads are to be exposed to the dangerous coal seams, more blastholes are arranged on the working surface, and more explosives are installed. The blasting is performed with a strong full section to instantly uncover the protruding coal seam. By using the strong vibration force generated during the shooting, the potential and gas in the coal seam are quickly released, thereby achieving the purpose of artificially inducing protrusion. In the case of vibratory shooting, in addition to taking other measures, the underground personnel should be evacuated to the ground and detonated on the ground. In order to reduce the impact on production, it is generally carried out at the time of handover. The prevention and control of coal and gas outburst is not a single technical measure, but a complete set of comprehensive and comprehensive prevention and control system engineering. Therefore, when mining outburst coal seams, it is necessary to adopt an effect test including prominent risk prediction, anti-burst measures and measures. A four-in-one integrated defense against security measures. The risk prediction of coal and gas outburst is divided into regional outburst risk prediction and outburst risk prediction. The task of regional outburst risk prediction is to determine the risk of coal and gas outbursts in coal seams and coal seams within the field. The task of highlighting the risk prediction in the working face is to determine the coal and gas outburst danger of the coal body near the mining face such as the Shimen coal mining face, the coal roadway face, and the coal mining face. According to the results of the outstanding risk prediction, the coal seam can be divided into protruding coal seams and non-outburst coal seams. In the prominent coal seams, it can also be divided into prominent dangerous areas and prominent threat areas. The highlighted danger zone can be further divided into a prominent dangerous work surface and a prominent threat work surface. According to the prominent risk prediction results and the division of the outstanding danger degree, it can guide the selection of the anti-burst measures that should be taken, so that the anti-burst work can be scientific, reasonable and effective. Therefore, the prominent risk prediction is the first important link in the four-in-one comprehensive defense prevention measures. The inspection of the anti-burst effect is based on the relevant provisions in the prediction of coal and gas outburst. The coal seam after the measures are taken to measure the outstanding risk index again. According to the measured index value, it is judged whether it falls below the critical value and whether there is any outstanding danger. . If the inspection results show that the anti-burst measures are effective, the mining operations can be continued after the safety protection measures are taken; if the anti-burst measures are invalid or not effective, additional measures must be taken. As the fourth component of the outstanding prevention and control measures, safety protection measures are an important part to avoid highlighting personal injury and death. Safety measures must be taken when the rock wells are exposed to the outburst coal seams and the mining operations are carried out in the outburst coal seams. The safety protection measures mainly include personal protective equipment such as vibrating and shooting, long-range shooting, reverse damper and self-rescue system, isolated compressed oxygen self-rescuer and chemical oxygen self-rescuer. Featuring a hinged lid, this black disposable plastic container can be quickly and easily closed to keep up with the fast-paced environment of your restaurant or take out venue.All the raw materials we use are food -grade and safety guarantee. Various size options for regular series and the smaller version series to meet all your needs. It's exceptionally durable and versatile. 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2. Local measures to prevent coal and gas outburst
1. Prevention of prominent regional measures - mining protective layer