Mining technical measures and ventilation measures to prevent spontaneous combustion of coal
First, the mining technical measures to prevent spontaneous combustion of coal
When mining coal seams with a tendency to spontaneous combustion, reasonable coal mining techniques should be used to prevent natural ignition of coal.
1. Choose a reasonable development method and coal mining method. To exploit coal seams with spontaneous combustion tendency, the development method of Shimen and rocky alleys should be adopted, so that coal seams can be cut less, coal pillars can be kept less, and the goaf can be closed and isolated. If it is necessary to open up the roadway in the coal seam and the service life is long, it should be built.
2. For coal seams with self-ignitability, back-type mining should be adopted, and forward-type mining is prohibited. It is necessary to select a coal mining method with high recovery rate, fast recovery speed and easy closure of the goaf. Therefore, the longwall mining method is suitable for mining coal seams with a tendency to spontaneous combustion. The filling method manages the roof and is good for fire prevention.
3. Reasonably arrange the mining area. When the mining area is arranged in the spontaneous combustion propensity coal seam, the size of the mining area should be determined according to the length of the spontaneous combustion period of the coal seam and the recovery speed. If the natural ignition period of the coal seam is not considered, the length of the mining area will be blindly increased, and the length of the mining area is often not finished, and the goaf has spontaneously ignited.
4. Improve the recovery rate and adhere to the regular cycle. The lower the recovery rate, the more coal is lost, the more abnormal the recovery, the easier it is to spontaneously ignite. Therefore, we should adhere to the regular cycle, speed up the recovery, clean the surface of the coal, improve the recovery rate, and timely release or fill.
5. Prevent natural fires in the roadway. First of all, we must ensure the quality of the roadway construction to prevent roofing. In the case of a roofway roof or a cavity formed by coal and gas outburst, it is necessary to remove the floating coal, lay the bracket, fill the loess or spray the inhibitor, and fill with inert gas to isolate it from the outside air to prevent oxidation of the coal. Second, the prevention of coal spontaneous combustion ventilation measures
1. Choose the ventilation system correctly. According to geological conditions, development systems, and coal mining methods, the mine ventilation system should be rationally selected. When the strike length of the mine is more than 4 km, diagonal ventilation or sectional ventilation should be adopted. If central ventilation is adopted, the ventilation resistance will be large, and the goaf will have more air leakage; the gently inclined coal seam mining near the surface and long inclined length will be adopted. Central boundary ventilation should be used.
2. Implement parallel ventilation to avoid series ventilation. The ventilation resistance of the parallel ventilation is small, the air leakage in the goaf is small, and it is beneficial to adjust and control the air volume. In the event of an explosion or fire accident, it is easy to control the wind flow and isolate the disaster area, and there are fewer casualties.
3. Correctly select the number and location of building ventilation structures. Downholes are used to control or direct the flow of wind according to production needs, and it is often necessary to construct ventilation structures such as dampers, wind bridges, wind walls, and wind windows. These structures are more numerous, which will increase the instability of the wind flow, which is not conducive to the fire prevention and control of the goaf and the closed fire zone, so it is necessary to correctly select the quantity and ensure the quality of the building. They can not be installed in the broken coal rock body with many cracks, nor can they be placed in the roadway along the empty (send) lane, otherwise it will cause a lot of air leakage, which is not conducive to preventing spontaneous combustion of coal.
4. Strengthen ventilation management and timely repair the roadway. The smaller the section of the ventilation tunnel, the greater the ventilation resistance and the more air leakage. Therefore, it is necessary to ensure sufficient ventilation tunnel section, and to repair the roadway of the roof, bottom sill, etc., which should be repaired in time; the materials and equipment should not be piled up in the roadway; the wall of the unused damper and windshield should be removed in time.
5. Correctly select the coal mining face ventilation system. Mining coal seams with short spontaneous ignition periods, Z-type and Y-type ventilation systems should not be used for mining surfaces, while U-shaped and W-shaped systems are conducive to preventing spontaneous combustion. After the mining surface is finished, it should be closed in time.
6. Timely use fire prevention measures such as grouting, injection inhibitor, and pressure equalization.
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