Realistic and rational development and mining methods are fundamental measures to prevent impact pressure. The main principles are: 1. When mining mining groups, the development of layout should be conducive to the mining of the liberation layer. 2. When dividing the mining area, reasonable mining order should be ensured to avoid the formation of stress concentration areas such as coal pillars. 3. The coal mining face of the mining area or panel should be propelled in one direction to avoid the opposite direction of mining, so as to avoid stress superposition. 4. In special parts such as geological structures, mining procedures that avoid or slow stress concentration and superposition should be adopted. 5, there is the risk of impact or ready to open up the seam of the roadway, permanent room, on the main (lower) mountain, mainly coal Lane slip and return airway should be arranged in the bottom layer of slate or no impact on the risk of the coal seam, so as to preserve and Reduce the risk of shock. 6. For the mining of coal seams with dangerous impact, the longwall mining method of managing the roof without leaving the coal caving method should be adopted. 7. The roof management adopts the full slump method, and the work surface bracket adopts a shrinkable bracket with integralness and protection capability. Mining the liberation layer is an effective and fundamental regional precautionary measure to prevent impact pressure. A layer of mineral (or layered) is first taken to enable the adjacent layer to be unloaded for a certain period of time. This unloading mining is called mining the liberation layer. The first liberation layer must select the coal seam with no tendency to impact or weak impact according to the conditions of coal seam occurrence. The time and space effectiveness of the mining must be ensured during implementation. Coal pillars shall not be left in the goaf so that the unloading action of each coal seam first can in turn maximize the “liberation†of the coal seam. After the mining of the liberation layer, the fallen vermiculite or filling material in the goaf is gradually compacted with time, and the stress in the goaf and surrounding rock gradually increases correspondingly, tending to the original rock stress level, so liberation The role of the layer is time-dependent, and the pressure relief effect and effect decrease with time. Therefore, the interval between the exploitation of the liberation layer should not be too long. Generally, the effective period of pressure relief is 3a when mining the liberation layer by all the slumping methods, and 2a when using the full filling method. For the lower ore layer, due to the alternating loading and unloading forces caused by the front and rear bearing pressures during the mining of the liberated layer, the structure of the lower coal seam and the properties of the interlayer rocks are changed to a large extent, in particular, their fissures are changed. And gas permeability, changing the structure and properties of coal rock, releasing potential elastic energy, eliminating or slowing down the risk of impact pressure. Introduction: The Chemical Pumps is a nationally designed energy-saving pump. The performance and technical requirements of the pump are designed according to the performance and size specified in the international standard ISO2858. We mainly produce chemical pumps for metal materials.
Uses: Widely used in industrial, urban water supply, drainage, can also be used for farmland, orchard drainage, for the transport of clean water or other liquids with physical and chemical properties similar to clean water
According to the different materials of chemical pumps , the application fields are classified as follows: Chemical Pumps Chemical Pumps,Submerged Chemical Pump,Forced Circulation Chemical Pump,Centrifugal Chemical Pump Sichuan Zigong Industrial Pump Co.,Ltd. , https://www.zgpump-global.com
Second, mining the liberation layer
Advantages: The advantages of chemical pumps are reasonable layout of the whole series of water conservancy, wide range of users, "back-open" structure, convenient maintenance, efficiency and suction reach the international advanced level
1) Chemical pumps (stainless steel) are widely used in petroleum, chemical, metallurgy, synthetic fiber, pharmaceutical, food, synthetic fiber and other sectors for the transport of alkaline corrosive media;
2) Chemical Pump (cast iron material) is used for industrial, urban water supply and drainage, and can also be used for irrigation and drainage of farmland and orchard for transporting clean water or other liquids with physical and chemical properties similar to clean water.
First, reasonable development and mining methods