Increasing safety in fieldamp mines by monitoring the asmosphere behind stoppings with the help of gas-chromatographic method

The paper addresses the issues related to the fight against spontaneous combustion and mine fires which are ignition source for the flammable atmosphere in underground coal mines. Flammable gases emitted during spontaneous combustion of coal and during mine fires comprise methane, and other saturated and nesaturated hydrocrabons, hydrogen and carbon oxide, the last ones resulted from coal pyrolysis / burning, as well from the secondary reactions (reduction of carbon dioxide to carbon oxide; reaction between water and gas that occurs when water or water vapours reach the incandescent coal). When hydrogen is involved in the formation of the explosive mixture generated by spontaneous combustion and mine fires, the violance of underground explosions shall increase, with strong dynamic results compared to methane explosion. For fighting against spontaneous combustion and mine fires, the working face in question shall be sealed with stoppings (dams) and there shall be performed inertisations with nitrogen and for monitoring the chemical composition of the mine atmosphere from both working face and behind dams, there shall be used gas-chromatographic method with a Clarus 500 type gas-chromatograph specially set for this purpose. It is very important to know and to keep under monitoring the chemical composition of the mine atmosphere and of the air behind dams in order to be able to provide safety both of workers and of coal deposits, and to be able to put back in service the isolated working face.