(1)In mines with mechanical ventilation, gas is easy to collect when the fan stops blowing. This is because the gas emitted from the underground mining face and the walls of the roadway cannot be discharged out of the well in time if the ventilation is interrupted. Therefore, a special person must be determined to be responsible for the maintenance, overhaul and management of the fan (main fan or local fan), improve the responsibility system, strictly prevent fan failures, ensure uninterrupted operation of the fan, and often deliver enough air volume to the underground mining site. Once the fan stops blowing, In areas where gas inspectors are not present and areas where gas exceeds the limit after inspection, personnel must be evacuated immediately and power transmission must be stopped. After ventilation is restored, gas inspection must be carried out first and no danger can be allowed to continue power transmission and resume production.

(2)In naturally ventilated mines, gas is easy to accumulate in spring and autumn. This is because the difference between the surface temperature and the underground temperature in spring and autumn is not large. Even if the height difference between the inlet and outlet wellhead is very large, a large amount of air cannot be supplied to the underground, and even there is sometimes no wind in the underground. If there is no wind underground, gas cannot be blown away with the wind and is easy to gather. Therefore, mines with gas cannot simply use natural ventilation. Especially in spring and autumn, mechanical ventilation, thermal ventilation, or steam jet ventilation must be used.

(3)Power outages in mining areas can easily accumulate gas, because power outages will cause power outages to the fans, and wind outages will inevitably cause gas gushing out of the underground to accumulate quickly and cannot be discharged. Therefore, mining, maintenance, blasting and electromechanical personnel must pay special attention to protecting electrical equipment, cables and wires and stop power outages. When mining personnel use electrical equipment, they should not overload it, lay wires and cables neatly, and do not drag the ground wire. When blasting personnel shoot, do not cut the power line as power supply. When repairing brackets, maintenance personnel should pay attention to preventing cutting or breaking wires and cables. Mechanical and electrical personnel must use separate lines or set independent switches on various equipment to install fans to avoid stopping the fan running while repairing other electrical equipment. If these measures are taken seriously, power outages and wind cuts will be prevented, gas accumulation will be avoided, and electrical lines and equipment will be prevented from being blown out, causing gas burning and explosion.

(4)Gas may easily accumulate in unventilated excavation tunnels and unfilled waste tunnels after stopping work. This is also because the release of gas from the roadway does not stop, and if there is no ventilation, it will inevitably gather. Therefore, ventilation must continue to be continued in the roadway where work has been temporarily suspended; ventilation must be continued in the roadway where work has been suspended for a long time and the roadway that has been abandoned must be immediately sealed or filled. Open the gas-filled roadway to seal and restore ventilation. When resuming work, never send the air duct into the roadway without control to blow air. Because this may blow out a large amount of gas and mix it with fresh air to reach the explosion limit, and explode when encountering an ignition source. Therefore, when discharging gas in this tunnel, we must not do it hastily. Special measures must be taken, assigned a special person or a ventilation area or rescue team should be responsible for it, and the discharge should be carried out gradually and in a controlled manner. The phenomenon of stopping work halfway up the mountain alone should be strictly prohibited. It is very dangerous when connecting a single-headed mountain, so holes should be drilled in advance to detect gas.

(5)Gas is easy to collect when driving through unventilated old holes, old alleys and close to closed faults. This is because a large amount of gas collects in unventilated old holes, alleys and enclosed faults. Once dug through, gas will suddenly flow out and cause an accident. Therefore, before digging through, the ventilation electromechanical department must first be notified to formulate special measures for gas discharge. Gas discharge is carried out after making preparations for ventilation and eliminating various fire sources. If conditions permit, it is best to exhaust gas through the original old holes and old alleys. When old holes and old holes that cannot be entered must be discharged from the excavation roadway, we must take measures to discharge them in advance and gradually expand the discharge hole to discharge them in a controlled manner. Whether it is discharged from old holes, old holes, or from excavation tunnels, if you are not sure to control the gas content in the return air flow to a safe limit, then the power supply must be cut off and personnel evacuated during the return gas discharge.

(6) it is easy to gather gas in single-head mining and long-distance roadway driving. Because there is no return air lane in single-head mining, ventilation depends on the local fan, and the ventilation is often interrupted due to mechanical and electrical failures or connecting to the air duct. When the ventilation is interrupted, the gas compressed in the old pond will inevitably gather to the mining site. At the same time, the farther the single roadway is, the longer the distance of the local fan is and the smaller the air volume is, which can not adapt to the situation that the farther the roadway is, the greater the gas emission is. Therefore, the gas content in the return air flow of the long-distance single roadway is relatively large, especially when the local fan stops and the air pressure drops suddenly, the gas compressed in the cracks in the coal wall and roof and floor will quickly gather into the roadway. In order to prevent gas accumulation in the working face, the single-head mining should be eliminated and the full air pressure ventilation with incoming air and return air should be used. In order to prevent the coal roadway and the single roadway from being too long, the ventilation distance should be properly specified according to the ventilation capacity of the local fan and the gas grade of the mine. The first and second-class gas mines should not exceed 30 meters, and the third-class gas mines should not exceed 30 meters. For the existing tunneling roadways that are too long, in addition to timely ventilation, special attention should be paid to the gas inspection of the whole roadway and the location of gas accumulation should be dealt with immediately.

(7)Gas is prone to gathering and gas explosion accidents are also prone to occur in locations where blasting coal mining occurs. This is because blasting breaks down a large amount of coal, exposing a large area of new coal walls and roofs and floors, which will release a large amount of gas

(8)Gas is easy to accumulate when the air pressure drops. This is because the gas compressed in the Laotang and coal cracks suddenly flows out after the air pressure drops. Therefore, when the air pressure drops, the reason for the air pressure drop should be immediately checked. If the air valve is not closed, the air valve should be closed immediately; if the air flow is blocked due to roof falling or coal accumulation or slag accumulation, it should be dealt with immediately. At the same time, it is necessary to strengthen gas inspection and ventilation and fire prevention work at mining sites near Laotang. If gas exceeds regulations, personnel must be evacuated immediately for treatment.

(9)At the roof gallows location, because gas is lighter than air, a large amount of gas can easily gather. Therefore, when digging and repairing a roadway, we must do everything possible to avoid roof collapse. Pay attention to the inspection of existing gallows roof collapse. If gas is found to accumulate, ventilation should be carried out, or filling and sealing should be carried out.

(10)Coal mining in single-eye wells easily collects gas. This is because the single-eye well has no air outlet path, the roadway is too tortuous, the route is too long, air supply is very difficult, and gas is not easy to discharge. In order to prevent gas accumulation in toxic hole wells, when the air shaft reaches the expected level, except for the necessary roadway for connecting the air shaft, no roadway can be opened for coal mining. Gas inspection must be strengthened for single-eye wells and single-lane supply channels, and local fans must be used to supply air to the excavation head. The fan must be installed on the ground and must not be installed in a blind hole to avoid circulating wind and causing gas accumulation

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