Underground fires are one of the most serious emergencies that occur during mining operations. Analysis of possible scenarios for its development is a mandatory measure when designing new mine workings and when developing a plan for immediate elimination of accidents at the existing mine workings. The main danger that an underground fire creates for the mine ventilation system is a change in the ventilation mode and, accordingly, a change in the direction of movement of the air and harmful gases released during combustion. It is almost impossible to calculate in manual mode all the possible scenarios for the development of an emergency for different places where underground fires occur.  This confirms the need to develop algorithms for automated assessment of the effect of thermal depression from a fire on the stability of the air flow in all mine workings of the mine ventilation network.
The authors consider two numerical algorithms implemented in the «Aeroset» analytical complex and solving two independent problems. The first of them is determining the air flow stability in the mine on the whole in the presence of a fire of a given heat emission rate in any place of the mine working.  The second task is to find the critical rate of fire heat generation in stationary workings, leading to a loss of stability of the air flow in the mined-out spaces of the mine. The techniques of increasing the speed of calculations of algorithms are studied. The article also describes the developed tools for graphical analysis of the calculation results. Examples of using such tools in practice are given. It is concluded that the developed software tools allow to quickly model the stability of air distribution in the mine ventilation networks of arbitrary topology in the presence of underground fires, and conveniently visualize the calculations.