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2. The concentration of harmful gases does not exceed the requirements of Table lG420103-1
3. The airflow velocity in the shaft shall comply with the requirements of Table lG420103-2.
(2) the sum of the coal mining, tunneling, copper and other locations actual needs chamber air volume is calculated. The actual required air volume at each location must be such that the concentration of wind, carbon dioxide, hydrogen and other harmful gases in the wind current at that location, wind speed and temperature, and the air supply per person comply with relevant regulations.
(3) According to the maximum amount of explosives used in the simultaneous shooting of underground mines, the fresh air supply per gram of first-class coal mine permitted explosives shall not be less than 25 hours/min; the allowable explosive supply per kilogram of secondary and tertiary coal mines shall not be less than 10m 3 / Min.
2. Determine the principle
(1) The principle of total mine supply is to ensure the safety of mine production and economic requirements.
(2) When calculating the air volume according to actual needs, the standby air volume should be avoided too large or too small. According to the results of the above requirements, the maximum value is selected as the air volume required by the mine.
(3) Coal mining enterprises should formulate air volume calculation methods according to specific conditions, and revise them at least once every 5 years.
3. At least one dedicated return air passage must be installed in each mining (disc) area of ​​high gas and outburst mines and in mining (disc) areas where easy self-igniting coal seams are to be mined; coal seam groups and layered mining in low gas mines are jointly arranged. In the mining (disc) area, a dedicated return air duct must be set up.
4. The partial pressure - type fan and starting apparatus, must be installed into the wind tunnel, the return air from the tunnel excavation can not be less than 10m.
5. The excavation working face that uses local fan ventilation should not stop the wind; when the wind is stopped due to maintenance or power failure, the personnel must be evacuated and the power supply must be cut off. Gas must be checked before ventilation is restored. The local ventilator can be manually turned on only when the gas in the airflow within 10m of the local ventilator and its switch does not exceed 0.5%.
6. Mine ventilation must be mechanically ventilated. The main ventilator must be installed on the ground. The wellhead with the ventilator must be tightly closed. The external air leakage rate should not exceed 5% when there is no lifting equipment, and should not exceed 15% when the equipment is hoisted.
7. The main fan must be operated continuously. It is strictly forbidden to use a local fan or fan group as the main fan.
8. It is strictly forbidden to install auxiliary ventilation fans in coal mines.
(1) Wind quality and wind speed requirements in the roadway
1. In the inflow of the mining face, the oxygen concentration is not less than 20%, and the carbon dioxide concentration is not more than 0.5%.
(2) The calculation and determination principle of the air volume required by the mine
Air flow calculation
(1) According to the maximum number of people working underground at the same time, the fresh air supply per minute per person shall not be less than 4m 3 .
(3) Important requirements for ventilation work
1. Before the roadway is drilled, the comprehensive mechanized roadway must be stopped before a distance of 50m and the other roadways are 20m apart. The work of adjusting the ventilation system must be done. After the completion, all work in the mining area must be stopped, and the ventilation system should be adjusted immediately. After the wind flow is stable, the work can be resumed.
2. The inlet wellhead must be placed in a place where dust, harmful and high temperature gases cannot enter. Safety measures should be in place where dust, harmful and high temperature gases can invade people.