Using the synthesized gas from underground hard coal or lignite gasification system has not been employed in Poland yet. In case of lignite it is especially important due the large reserves of this fuel (Kozlowski et al., 2008; Kudelko, Nowak, 2010). Using lignite for synthesized gas production would result in applying it in power and chemical industry. In many cases it would be possible to get the power from solid fuel without its extraction on the surface. It is extremely important in regions, where local community protests against open pit mines. On the areas where surface infrastructure is developed, there would be an opportunity to obtain the chemical energy contained in brown coal with minimal interference in local plans of land development. Therefore there is a great interest in this mining method as a clean coal technology (Kudelko & Nowak 2010; Kudelko & Nowak 2007; Nowak 2007).