Model of Heat and Mass Exchange between a Downcast Shaft and the Air Flow to the Mine

Mining activities have increased owing to the rise in the social demand for minerals. Thermal hazards have become a major health and safety consideration in mines. The thermal environment of a working face is related to the air parameters at the bottom of shaft. The objective of this study is to accurately predict the air temperature at the bottom of a shaft in a mine with the ventilation time over 3 years. For this purpose, a mathematical model of the heat and mass exchange between the surrounding rock of the shaft and the downcast air is established by utilizing the finite volume method. The C++ languages are used for numerical calculations. The results are in agreement with the measured data. The effects of the relative humidity of air at the inlet of the shaft, the surface moisture coefficient of the shaft surface, and the physical parameters of the rock on the air parameters at the shaft bottom are studied in detail. Equations for calculating the enthalpy increase of air per 100 m in shaft with the depth of 1300 m were established by using cluster analysis. This equation provides a theoretical basis for predicting the air parameters along the shaft with the ventilation time over 3 years.