Factors influencing dynamics of CO2 content within the underground space (the case of Kungur ice cave)

Monitoring of changes in carbon dioxide concentration in the Kungur Ice cave was conducted from September 2017 to February 2019. Carbon dioxide was an important component of the gas composition of the cave, since its elevated values during excursion activities could be dangerous to human life. Constant monitoring allows to avoid negative consequences and take measures to prevent them. This paper presented a generalized analysis of factors that affect the concentration of carbon dioxide in the underground space. In the course of the research, the main (temperature conditions on the surface and in the cave) and secondary (pressure in the cave, fracturing, mineralization of water) factors influencing the dynamics of carbon dioxide content in the grottoes were identified. A correlation estimate was made between CO2 variations, microclimatic parameters (surface and cave temperatures, pressure in the cave) and lake water mineralization. In winter and summer periods of 2019, one-time measurements of air flow velocities were carried out in different microclimatic zones of the cave, fracture coefficients of the massif of Ledyanaya gora within the development of the cave and air flow were calculated to establish a relationship between carbon dioxide concentration, air flow and mass fracture.