In this article, the mass and heat balance calculations of underground coal gasification process for thin coal seams in faulting zones of Lvivskyi coal basin (Ukraine) are defined. The purpose of the research is to establish regularities of heat and mass balance changes in faulting zones influence due to usage air and oxygen-enriched blast. A comprehensive methodology that included analytical calculations is implemented in the work. The output parameters of coal gasification products for the Lvivvyhillia coal mines are detailed. The heat balance is performed on the basis of the mass balance of underground coal gasification analytical results and is described in detail. Interpretations based on the conducted research and investigation are also presented. Conclusions regarding the implementation of the offered method are made on the basis of undertaken investigations. According to conducted research the technology of underground coal gasification can be carry out in the faulting zone of stable geodynamic and tectonic activity. The obtained results with sufficient accuracy in practical application will allow consume coal reserves in the faulting zones using environmentally friendly conversion technology to obtain power and chemical generator gas, chemicals and heat.