Gas refers to all kinds of toxic, flammable and explosive gases underground;
2. Coal dust refers to coal dust that can explode and coal dust whose concentration can cause pneumoconiosis;
3. Water refers to water gushing or water gushing that can lead to mine flooding or casualties;
4. Fire refers to all kinds of underground fires;
5. Roof disaster refers to all kinds of collapse or caving accidents of the rock strata at the top of coal mine roadway or mining area.
Roof accident
Roof disaster is the most common and prone accident in coal mine. Among the five disasters (coal dust, water, fire, gas and roof) in coal mines, roof accidents rank first among all kinds of accidents in coal mines, no matter the number of occurrences or the number of deaths.
With the mining of the working face, the roof strata above the coal seam lose support, the original pressure balance is destroyed, and the roof of the coal seam is deformed and destroyed under the pressure of the overlying strata. If our support is not timely or the support strength is not enough, it is easy to cause the roof strata of the working face to break and fall, resulting in casualties and loss of property and equipment. This is what we call a roof fall accident.
Gas dust
Coal seams are often accompanied by gas (methane, etc. ). Gas is easy to cause explosion accidents. Therefore, when working in a closed space, it is necessary to monitor the gas concentration frequently. If there is a certain concentration of dust in the gas, it may also cause an explosion because of Mars. The dust volume is small, but the relative proportion of the surface is large. If there is enough oxygen in the surrounding air, it will be very sensitive to the combustion reaction.
Gas jet
Gas itself is harmless to human body, but sometimes it is accompanied by toxic gases such as carbon monoxide. If a large amount of gas is ejected at one time, the possibility of gas explosion will usually increase rapidly.
Pit fire
The worst case in a coal mine accident. Different from ordinary fires, there are many combustible materials (coal) around. If the tunnel is blocked by high temperature and smoke and lacks oxygen, it will usually cause heavy casualties.
Flooding
The accident that the mining area collapses at the bottom of the water (near the seabed, lake or reservoir) is worse than the fire in the pit, and there is almost no possibility of survival. A large number of floods swallowed up the tunnel in a short time, killing all the staff.
Usually the survivors can't be rescued, the remains can't be recovered, and the tunnel is abandoned. Water inrush and leakage accidents may also occur when mining on confined water and re-mining in damaged areas of small coal mines. Underground water inrush and small coal mine flooding accidents are far more than coal mine flooding accidents.
References:
Coal Mine-Baidu Encyclopedia