(1) When the first mining face of the sea area is put into operation, the main fan exhaust air volume is about 6000m3min, but the mine negative pressure far exceeds the limit value of the national coal safety word <1988>291 document 0 (the main fan exhaust air volume is 500010000m3min). When the mine negative pressure does not exceed 2450 Pa), it is a high-resistance mine. (2) The North Soap Coal Seam is an easy-to-self-ignition (grade) coal seam, which belongs to the first-class spontaneous combustion mine. The natural ignition period is less than one month. In addition, the mine is a three-soft 0 stratum. Therefore, the mine negative pressure is too high and the direction is increased. The air leakage oxygen supply intensity of the goaf and coal body cracks 0 increases the difficulty of controlling natural fire management. (3) If the negative pressure of the mine is too high, it will cause difficulty in opening the damper for traffic and pedestrians, and it will easily cause damage to the facility, and it is difficult to keep the ventilation system stable. This will lead to major hidden dangers such as insufficient air volume and gas accumulation. (4) The negative pressure of the mine has increased greatly, resulting in the current 1K58-N24 (motor rated power 310kW, speed 1000rmin) main fan capacity can not meet the requirements, need to be replaced into a high-power fan, the above unreasonable and unfavorable factors The existence of the East has forced the East to be completed and put into operation one year before the first mining face of the sea area was put into production (when the sea area was increased to five independently ventilated tunneling faces). Since the construction period of the first mining face of the deepening project in the sea area is 4 years, if the construction period of the wind shaft construction is estimated to be 3 years, the construction of the deepening project in the sea area will be carried out at the moment, which will bring great economic burden to the enterprise. Therefore, it is necessary to solve the measures to transform the existing ventilation system. Transformation plan (1) The main method of reducing the resistance of the mine is to take the following measures: make up the air duct. Through the calculation and analysis of the ventilation network, it is known that after the sea area expansion area is put into operation, the high-resistance section of the ventilation network is located at the -175 east auxiliary lane of the upper group coal-175 level to the total return airway of the mine. The 3490m air duct (accounting for 29% of the total ventilation process), the average net section of the section is less than 7m2; the return air volume is more than 40m3s; the ventilation resistance of this section is about 1400Pa, accounting for 42% of the total ventilation resistance of the mine. Therefore, It is necessary to make a length of 500m, and the net section and the 3490m air duct of the section form a parallel return air network, which reduces the ventilation resistance from 1400Pa to 240Pa, which is 83%. Expand the air duct. The 540m air passage in the upper section of Huifeng Lane 0 in the fourth mining area of ​​the upper group of coal-175 level in the sea area of ​​the enlarged area of ​​the sea area has an average net section of less than 5m2 due to deformation of the bottom drum and the ventilation resistance reaches 330Pa or more. It is a local high ventilation resistance section, so expansion measures are required. That is, the net section of the ventilation is expanded to 7m2, and a parallel return air network is formed with the track lane of the four mining areas, so that the ventilation resistance is reduced from 330Pa to 30Pa, which is 91% lower. After adopting the excavation and expansion of the 0 air duct measures, the mine ventilation resistance will be reduced from 3300Pa to 1840Pa (down 44%), thus meeting the requirements and the need for mine ventilation safety. (2) Reform the fan. The transformation measures are as follows: Replace the 1# fan. Since the original 1# fan is a phase-out product, spare parts have not been purchased, and the efficiency is low (less than 50%), the power consumption is large, and the operation is uneconomical. Therefore, it was replaced with a KZS-N24 axial flow fan with a motor rated power of 475 kW and a rotational speed of 750 rpm. After replacement, it is used as a fan. 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