Comparison of artificial refrigeration cooling schemes for high temperature tunneling roadway in deep mines--the case of Yunnan Dahongshan Copper Mine

With the increasing depth of metal mine mining, the heat damage in deep mine tunneling roadway has become more and more serious, in order to effectively reduce the temperature in high temperature tunneling roadway, a mobile artificial refrigeration equipment was developed. To improve the efficiency of cold-heat exchange of air, enhance the cooling effect of the refrigeration equipment, evaluate the applicability of refrigeration equipment and determine the optimal cooling scheme, field tests under different conditions were conducted in Dahongshan Copper Mine in Yunnan Province. Additionally, numerical simulation studies were carried out by Fluent in order to analyze the temperature distribution characteristics of the roadway under different conditions. The results show that: (1) The mobile artificial refrigeration equipment can reduce the wet bulb temperature in the cooling space to below 30 °C, meeting the requirements of the " Safety regulation for metal and nonmetal mines " (GB16423-2020), and condition 4 has the best cooling effect, which can reduce the wet bulb temperature in the cooling space to below 23.64 °C; (2) The addition of cold air supply duct, wind barriers and heat exhaust ducts enhances the cooling effect in the cooling space; (3) The highest average axial temperature of the roadway is observed at the location of 6m from hot air outlets of the refrigeration equipment or heat exhaust ducts outlets, and the highest temperature is about 9 °C higher than the initial ambient temperature of the roadway; (4) The cold air in the cooling space gradually contracts towards the cold source outlet as the distance from the working face increases. The research results can provide guidance for the prevention and control of heat damage and the development of artificial refrigeration equipment for high temperature tunneling roadway in metal mines.