The article describes climatic and mining-technical conditions influencing frost formation process. It was noted that the radical tools for preventing frost formation in winter periods is creation of positive temperature in tunnels by heating the incoming outside air. We formulated tasks, which solution will promote development of engineering calculation method for heating systems parameters. The article provides results of theoretical studies based on mathematical modelling and analytical solutions and data on field instrumental measurements, which were processed with similarity criteria. It compares mathematical modelling results on determining amount of tunnel incoming air flow with portal gates and calculations data from experimentally determined coefficient of local resistance. We proved the energy efficiency of placing the tunnel portal gates and validated the places of preheated air injection points and removal of cool air from this flow, which provides maximal energy effect.