Fire hazard in metal mines

(4) Variability. In the underground part, the position, form and degree of danger will change with the continuous development of mining operations and the constant change of natural environment, and the state of its danger source is always in dynamic change. And there are many factors affected. The existence state of the hazard source is affected by many factors such as the selection of mining method, geological and natural conditions of the deposit, blasting operation, machinery type, cavitation form and production management level.

(5) concealment. Because there are many factors affecting the risk source, and the change is large. Therefore, the monitoring and control means and methods require higher requirements, especially the dangers that can be detected by precision instruments, such as ground pressure activities, a large number of toxic and harmful gases, etc., are concealed.

(6) Contingency. One of the main reasons for the high accident rate of mining enterprises is that it is difficult to estimate the degree of damage caused by hazard sources. Some accidents happen in an instant, and some big events do not happen for some reasons, so it is difficult to quantitatively analyze the severity of the hazard.

Hazards of mine fire hazards

Mine fire will bring particularly serious harm to the lives of underground personnel, the main reasons are:

(l) The underground space is narrow, the connection relationship between mine ventilation and roadway is complex, and the air supply is limited. In case of fire, personnel will be limited by the underground environmental conditions.

(2) Mine fires will produce a lot of high temperature smoke, and the temperature near the fire source is often above 1000℃. The large amount of smoke and heat generated by the fire is not easy to dissipate in the mine. In the case of ventilation in the roadway, the high temperature smoke flow can quickly spread to a large range with the wind, so that the personnel in these areas are harmed by high temperature. In addition, the smoke generated by the fire will block people's line of sight and reduce the visibility of the air, thus hindering the safe evacuation of personnel and the smooth progress of disaster relief and fire fighting [19].

(3) Fire smoke with a large number of toxic and harmful gases and vapors and smoke, not only on the human eyes and respiratory organs have a strong irritating and asphyxiating effect, but also in the smoke of carbon monoxide, hydrogen and hydrogen sulfide and other toxic and harmful gases, so that the oxygen concentration in the air flow is also greatly reduced. Such gas is inhaled by the human body will cause human poisoning, asphyxiation and other casualties. It can be seen from a large number of fire accident cases at home and abroad that the main cause of casualties during fire is smoke poisoning and asphyxia.

(4) The development of a mine fire to a certain intensity (such as fire wind pressure) may cause changes in the direction of the mine ventilation network, so that the flow of smoke is out of control, further expanding the disaster area, so that more underground personnel are poisoned by fire smoke. At the same time, it brings great difficulty and danger to the underground safe retreat. Due to the disturbance of air flow in the ventilation network during mine fire, it is easy to induce gas and coal dust explosion accidents.