Existing work to determine the necessary amount of air for liquefaction and removal of harmful impurities in the chamber-shaped workings are based on the fact that the movement of air entering the chamber, occurs according to the laws of free turbulence. Depending on the configuration of chambers, round or flat free jets are formed in them, acting in a limited space. Distribution of harmful impurities in the volume of chambers and their removal by free jets occurs due to their displacement by the nuclei of constant masses, in which through each cross-section the flow rate maintains a constant value. Proceeding from this basic provision, formulas for calculating the required amount of air at periodic (blasting operations) and continuous (drilling, scraping) sources of formation of harmful impurities are given. Most of the proposed formulas in one form or another clarify the boundaries of application of the known formula ...