In the underground mining operations the most important is the safety of, so being update with procedures, standards and regulations is a very important issue, in this article we will briefly touch the use of self-rescuers, a crucial element in the evacuation of underground mines in case of a fire.

The self-rescuer is a special protective element that should only be used in the event of a fire inside the mine. This equipment protects us from carbon monoxide poisoning, and can be used only once, to escape from a polluted environment. The duration of the self-rescuer depends on the concentration of carbon monoxide, the temperature, the relative humidity of the environment, and the volume of air exhaled by the user. Usually the duration of these equipment is from 30 to 60 minutes.

Oxygen masks to produce O2 in emergency situations contain potassium superoxide, KO2, which reacts with CO2 and H2O from the exhaled air (in vapor form) to generate oxygen as shown in the following equation:

4 KO2 (s) + 2 H2O (g) + 4 CO2 (g) ———> 4 K (HCO3) (s) + 3 O2 (g)

KO2 is a rare salt of the superoxide ion produced by the burning of molten potassium in pure oxygen.

The chemical reaction occurs in this way: When breathing, the exhaling water (steam) and CO2 react with the oxygen generating agent (KO2) to produce chemical oxygen, which will enter the breathing bag through the chemical container.

When using the self-rescuer in the presence of carbon monoxide, the air that breathes through the mouth will be hot and dry, this is a signal to maintain the use of the self-rescuer, as long as the air is hot and dry it should continue to be used, even if the air becomes very hot, you should not stop using the rescuer, or speak during the evacuation.



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