Methane gas accompanying coal deposits was formed as a result of successive stages of the anaerobic process of vegetal material transformation into coal, at high temperatures and pressures, without external oxygen supply. During the metamorphism process, the content of C, H and O is modified, meaning an increase in carbon content, a decrease in hydrogen and oxygen, the nitrogen and sulphur content remaining constant. During this process, water and carbon dioxide is generated, the water being generated in the first transformation phases. Within the slow oxidation process, gas products result by using the oxygen content in plants, especially methane and carbon dioxide due to the fermentation stimulated by bacteria. Methane released into the atmosphere following the mining of coal have double ecological impact, participating in the destruction of the ozone layer and at the same time contributing to the enhancement of the greenhouse effect. At the same time, methane gas released into the atmosphere during coal mining may be used by mining operators as primary power resource for covering the power requirements of the mine or it can be used for commercial purposes.

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Methane emitted by the hard coal mines in operation in the Jiu Valley coalfield is under study in order to find out the most suitable solutions that increase occupational health and safety and at last, but not in the least, to capitalize the power generating potential of it. From the point of view of occupational safety, methane displays the highest risk because it can give birth to an explosive mixture with the air and the coal dust. Methane discharges into the outer atmosphere have a negative impact, increasing the greenhouse effect, with serious consequences over the parameters of the climate. This paper focuses on the use of mine gas in three important stages: solutions for the use of methane discharged by central degassing stations for power generating purposes; development of the network for the drainage of gases and increasing the volume of recovered methane; solutions for the use of CH4 from the general ventilation.