As the upper ore body did not timely block the old roadway and caving area during the mining process, and the destruction of the Beifengjing pillar by the mining site, the air leakage of the ventilation system above the 270m level was serious, which greatly affected the deep excavation. Ventilation effect of the part. To this end, in 1991, the new method inclined shaft was replaced by the north wind well as the return air well, and the original two ordinary fans with an installed capacity of 630 kW were changed into two energy-saving fans with an installed capacity of 220 kW. This is the first ventilation. System transformation. Although the first transformation did not significantly shorten the ventilation line, it effectively controlled the air leakage in the return air section, and the ordinary fan was replaced by the energy-saving fan, which greatly improved the ventilation effect, reduced the power consumption, and achieved obvious results. The ventilation system after the first transformation maintained a good ventilation effect for a long period of time. However, with the further decline of the mining level, the middle section of 220m has ended. At present, the main production level has been transferred to the middle level of 170m, and the output has dropped drastically. After entering the final stage of mining, the ventilation system has also changed.
Current status of ventilation system and existing problems After entering the final stage of mining, the ventilation effect has not been improved due to the reduction of production area, the decrease of production and the reduction of air demand. On the contrary, due to various factors, there are many air leakage in the ventilation system, resulting in chaotic airflow in the downhole, returning air from the auxiliary well, reducing the effective airflow through the working surface, and the production environment is deteriorating, resulting in a 170m horizontal north before the transformation. The main return air inclined shaft has a sudden decrease in air volume, the central part of the wind is still, the pollution wind naturally spreads, and the southern auxiliary shaft returns to the wind. After investigation and analysis, the main causes of this situation and the main problems of the ventilation system are as follows: (1) Compared with the wind-demand section, the entire ventilation system is too long, especially the return air section is too long. Excessive bends and different cross-sections result in excessive wind resistance and low efficiency of the fan. (2) The return air section of the ventilation system is affected by the mining ground pressure and the destruction of the civil mining point, which makes the roadway deformed and collapses seriously. There are many openings and serious air leakage, which causes the wind current to be short-circuited, and the effective air volume of the system is greatly reduced. (3) The ventilation system needs to be closed in the old roadway and caving area of ​​the wind section, and the people have more diverted channels, which makes the horizontal leakage of each section serious, disrupts the direction of wind flow, destroys the air volume distribution, and reduces the effective air flow of the working face. . (4) A large amount of air leakage from the return air section and the wind demand section of the ventilation system replaces the air volume supplement of the air intake well, and the topography and climatic factors cause the return air phenomenon of the auxiliary well.
Reconstruction measures and characteristics (1) The surface extraction type return air is changed to the underground discharge type return air. Demolition of two 110kW wind turbines on the surface, at the beginning of the downhole return section, that is, at the 170m level, the northern end of the transport lane is close to the main return air inclined shaft, and a fan of the same type is installed to change the surface pullback type return air into the downhole discharge type return air. The dirty air is discharged to the surface through the original return air line or through the mouth. The change of this return air mode has greatly shortened the working distance of the wind turbine, and the operating efficiency of the wind turbine has been effectively exerted. At the same time, it is unfavorable to be advantageous, and the problem of short circuit and difficult maintenance of the return air section is well solved. Therefore, although a fan is reduced, a good ventilation effect is achieved. (2) Further optimize the ventilation line and air volume distribution. At the same time, the air intake section, the waste roadway, the caving area, and the civil mining opening are sealed. The ventilation line is further measured and confirmed. According to the different air volume requirements of different working parts, the ventilation structures such as the damper and the wind barrier are reasonably set. The ventilation line of the underground working face is the shortest, the air volume distribution is optimal, and the effective air volume of the system is further improved. (3) Dynamic management of the ventilation system. At the same time of renovating the ventilation system, higher requirements are put forward for the management of the ventilation system in the future. According to the change of the mining site, the ventilation structure and the air volume are adjusted in time by adjusting the ventilation structure, and the finished operation part and the caving The district timely blocked and introduced fresh airflow to the newly opened working face in time to ensure that the ventilation system can meet the ever-changing production needs and create a better working environment for the employees.
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