The task of mine ventilation involves the constant exchange of air within the mine construction through continuous flow, primarily aimed at providing conforming conditions suitable for work and diluting the concentration of suffocating, toxic, explosive gases, and dust, while transporting them to the surface. Intensification of production in underground mines, which results in an increase in diesel-powered work units, an increase in the number of employees, and deepening the mine, creates a demand for larger quantities of fresh air. In most cases, this is provided by installing increasingly larger main mine fans. This paper will present an analysis of the achieved results of improving the ventilation system in a polymetallic underground mine of lead, zinc, gold, and silver. The analysis will address the physical parameters of the air, such as flow, velocity, temperature, and relative humidity.