Optimization and transformation of ventilation system in Jining No.2 Coal Mine

Currently, there's a lack of research on air volume regulation and mine resistance reduction of ventilation system in mine working face. In order to solve the above problem, taking 10303 working face and 33_low 02 working face of Jining No.2 Coal Mine as the engineering background, the original ventilation systems in these two areas are optimized and transformed in terms of air volume regulation and mine resistance reduction. The ventilation system diagram of the working face is imported into Ventism software, generating a solid roadway and iterating the calculation to construct a mine ventilation network solution model. The main parameters measured on-site are input into the model for airflow calculation. The errors between calculated relevant data such as flow velocity, temperature, and air volume in the roadway obtained and the on-site measurement data are within the standard range. From the measurement results of mine ventilation resistance, it can be seen that the original ventilation system has the following problems. The setting of the regulating air wall at the south wing stone gate is unreasonable. The actual air supply volume of 33_low02 working face is less than the ideal air volume. The ventilation route of the south wing -740 horizontal track main roadway is long. It is affected by the parallel intake of auxiliary transportation roadways, resulting in high resistance in the south wing return air main roadway. In order to solve the above problems, three renovation measures are proposed. ① A closed air door is installed at the intersection of the south wing return air stone gate and the north wing belt conveyor roadway. The original air window area of the south wing belt conveyor roadway and return air stone gate is adjusted to 2.9 m². ② A 0.1 m² adjustable wind window is installed at the intersection of the extension of the third mining area's track downhill and the 33_low02 connecting roadway. ③ The 0.9 m² adjustable air window at the interface between the pipe duct in the 11th mining area and the south wing -740 horizontal track roadwayhas been changed to 2.4 m²,so as to reduce the air volume of the south wing -740 horizontal track roadway and increase the parallel air volume of the auxiliary transportation roadway. The simulation results of the modified ventilation system show that the resistance of the southern wing -740 horizontal track main roadway has been reduced by 32.7%. The air volume of the 33_low02 working face has been increased by 19.8%. The total resistance of the mine ventilation route has been reduced by 6.4%. The on-site measurement results of the modified ventilation system show that the average relative error between the measured air volume and numerical simulation results is 1.28%. The average relative error between the measured resistance and numerical simulation results is 2.52%. The optimized simulation results are basically consistent with the on-site test results. The range of changes in air volume and resistance of the intake shaft before and after the entilation system adjustment is not significant. The air volume at the measuring point of the return air shaft decreases, and resistance decreased. The optimized measured air volume at the 33_low02 track connecting roadway and the measuring points of the working face increase by 25.3% and 21.4%, respectively, and the resistances increase by 57.4% and 41.1%. The optimized measured air volume at the south wing -740 horizontal track roadway decreases by 20.3%, and resistance decreases by 36.6%. After the renovation, the air volume of the working face and the total resistance of the mine have achieved the expected results.