Harm and prevention of the hottest gas and coal du

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Hazards and prevention of gas and coal dust

common natural disasters in coal mines where researchers melt polymer powder in ovens include roof, water, fire, gas and coal dust, which are referred to as "five hazards". Among them, the management of gas and coal dust is the top priority of coal mine safety management. With the deepening of mine mining depth, the amount of gas emission gradually increases, and the occurrence of intermediate ground pressure and abnormal gas inrush occurs from time to time, At the same time, it also seriously threatens the safety production of the mine. The core of the "one ventilation and three prevention" work is still the prevention and control of gas and coal dust accidents

I. formation of gas and coal dust

gas is the general name of harmful gas emitted from coal and rock in the process of mining. Its main component is methane (CH4), commonly known as biogas. It is a colorless, tasteless, odorless gas, and it is flammable and explosive, which is the greatest harm to safety production. There are many hypotheses about the origin of gas. Most people believe that coal seam gas is a humic organic matter, which is the gas product associated with the coal formation process. Its formation can be roughly divided into two stages (periods), that is, from plant remains to peat belongs to the period of biological gas generation, and from lignite, bituminous coal to anthracite belongs to the period of coal metamorphism gas generation. Most of the gas produced in the first stage is lost in the paleoatmosphere through infiltration and diffusion, and is generally not preserved in coal seams. In the metamorphic age, most of the carbon dioxide was absorbed by the flow of groundwater and disappeared; Because the action points and fulcrums of the uplift load of the formation can also be interchanged, eroded and fractured, as well as the reasons of methane itself, driven by its pressure and concentration difference, methane is transferred and diffused, some or most of it is lost to the atmosphere or transferred to the surrounding rock, and only a small part is preserved in the coal layer or meets good sealing and storage conditions during migration, forming a coalbed gas field

coal dust is dust, the main component of which is coal, and the content of free carbon dioxide is less than 10%, which is a fine particle in the production process of coal mine. In coal mine production, almost all operations, including coal mining, transportation, lifting and other processes, can produce mineral dust

however, the amount of mineral dust is not absolute, but varies with geological conditions, coal seam occurrence conditions, coal and mining methods. Generally speaking, the company has the right to underwrite some spodumene concentrates of the pilgangoora lithium mine project with reference to the market price. If there are no dust prevention measures in the coal mine, the amount of coal dust produced every day and night is about 1% of the coal mining volume

Second, the harm of gas and coal dust

gas explosion must meet three conditions at the same time: first, the gas concentration is within the range of 5% - 16%; Second, a high-temperature heat source with a certain temperature. Generally, the ignition temperature of biogas is 650oc; Third, the oxygen concentration is generally above 12%. The harm of gas explosion is mainly manifested in two aspects; First, high temperature and high pressure caused casualties and destroyed mine equipment; The second is the generation of harmful gases such as CO, which is the main cause of personal injury

gas explosion is one of the most serious disasters in coal mine production, and even causes secondary disasters such as coal dust explosion, mine fire and roof fall, which aggravates the consequences of the disaster and makes it difficult for production to recover in a short time. After some coal seams are mined to a certain depth, coal and gas outbursts can also occur in the production process, causing great damage

coal dust is another major hazard in coal mine production. Its harm mainly has two aspects: on the one hand, it causes occupational diseases - coal lung disease and coal silicosis; On the other hand, coal dust can explode. Coal dust explosion has great harm. First, coal dust explosion can release a large amount of heat energy, and the explosion temperature can be as high as 2000oc or even higher. Such a high-temperature heat source can ignite coal dust of a certain concentration again, causing it to explode; Second, when the coal dust explodes, the temperature rises sharply and the pressure increases, up to 0.7~0.8mpa; The third is to produce strong shock waves and flames; Fourth, it produces a large amount of carbon monoxide and has the characteristics of long service life without protection. The content of carbon monoxide can reach 2%~3%, or even 8%, while the content of carbon dioxide can reach more than 10%, which is an important reason for causing a large number of casualties. Coal dust explosion must also meet three conditions: first, coal dust is explosive, second, floating coal dust in the air has a certain concentration, and third, there is an ignition source that can ignite coal dust

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