Nippori 1300 Face design coal mine recoverable strike length 750m, the initial plagioclase 150m. From January 1st, 2013, the test was taken, and on February 1st, a total of 32m was advanced (the roadway was 30m and the return air was 28m). According to the initial pressure and mine pressure in the mining face of the mine, the initial pressure range of the forecast is 18~23, and the pressure step is 25~18 m. According to the data displayed by the KJ24 mine pressure online monitoring system, the support pressure has been at a low level since the initial mining, between 20~30Mpa. From the morning shift on February 1st to the night shift on February 3rd, when the working surface is advanced to 15.5~18.5m, the support pressure of the KJ24 mine pressure online monitoring system in the middle of the reaction surface continues to rise, 1~ after the bracket is pulled into position. The pressure within 3 hours was rapidly increased from 20 Mpa of the initial liquid supply to the highest pressure valve operating pressure of 40 Mpa, and the working pressure of the stent was maintained at 40 Mpa. Until the pressure drop occurred on the morning shift on February 4, the pressure gradually recovered to between 20 and 30 MPa, and only a certain interval reached the 40 Mpa safety valve action position, but the duration was short and quickly fell back to the normal range. According to the above situation analysis, the working face is subjected to the maximum pressure section during the period of 15.5~18.5m, and the span of the old top rock beam reaches the maximum limit before the fall, and the rock beam fracture occurs. When propelled to 24m, that is, at about 16:10 on February 8th, the broken rock beam rotates and falls within the huge space formed after the mining, resulting in a large amount of high-concentration gas accumulated in the space of the goaf. And the shelves are pouring out. However, the pressure displayed on the work surface bracket did not change significantly, and it was maintained at 18~28Mpa, and the pressure on the support was relatively low. Therefore, it is judged that the working face is pushed to the initial pressure before and after 24 m. According to the pressure step, it is expected that the first pressure-inducing process may occur in the 35~40m section of the working surface, that is, during the period of 4~9m from the 18th, there will be a first cycle to show the pressure. It is necessary to take precautions in advance. Recommended actions: 1. Gas management uses pumping as the main means of treatment, increasing the pumping capacity of underground moving and ground fixed drainage systems, and extracting the high concentration within the mining range and the recovery space in advance, so that the gas content falls within the specified range. 2, balanced production, to ensure that the gas behind the coal body is evenly released into the mining space, to maximize the gas into the drainage system to avoid discharge to the return air system. 3. Ensure two advanced support distances (100m in the tunnel, 80m in the return air, and 0.6m in the row). The center pillar is added 30m away from the coal line, and it is erected with one beam and three columns. 4. The upper part of the working face is under pressure and the gang and the top section are connected to the net to control the coal gang. 5. Ensure that the pumping pressure of the pumping station is above 30Mpa. After the bracket is pulled into position, the liquid supply in time will reach the initial supporting force of the design. 6. The monitoring center must constantly check the gas probe to ensure the accuracy of the gas probe and the sensitive reliability of the power failure. Production Technology Department February 17, 2013 FM-C Series Fiber marking machine, a breakthrough innovation through continuous exploration, is designed by mechanical engineers, industrial designers, electrical engineers and other technical personnel of our company. it is a perfect interpretation of what beauty is in mechanic, industry and product itself. Small and portable, suitable for working on big workpiece Fiber Laser Engraver,Portable Type Laser Marker,Laser Engraver For Metal,Laser Engraved Pendant Shandong Meiman Laser Technology Co., Ltd. , https://www.meimanlasers.com
Working surface cycle
Working surface cycle