Study On Thermal Environment Analysis And Thermal Damage Prevention Technology Of High Temperature Mine Working Face

With the increase of mining depth,the problem of heat damage in the working face of metal mines has become increasingly prominent.In order to effectively reduce the temperature of working face and provide a comfortable working environment for miners,taking the Dahongshan Copper Mine as the research object,comprehensively using theoretical analysis,field experiments,numerical simulation and other methods,the thermal environment of high-temperature mine and the prevention and control technology of heat damage were studied.Firstly,the thermal environment analysis methods such as mine thermal parameter test,geothermal distribution test and heat source heat release calculation were discussed.Then,the mobile refrigeration heat damage prevention technology was researched.Finally,a SET evaluation method suitable for thermal comfort evaluation of miners was established to comprehensively evaluate the effect of heat damage prevention.The main research results in this paper shown as following:(1)Taking the west section of Dahongshan Copper Mine as the research object,the identification and analysis of heat source in high temperature mine thermal environment were carried out.The results showed that the thermal conductivity of the ore rock in the west section of the Dahongshan Copper Mine was large,the temperature of the original rock was high,the geothermal gradient was large,and the heat damage was serious.Heat release from surrounding rock was the main type of heat damage in Dahongshan Copper Mine.(2)The heat damage control effect of mobile refrigeration technology in high temperature working face was explored.Based on the concept of "cooling on demand" and the characteristics of the mine environment,the mobile refrigeration equipment was customized and developed by calculating the cooling load of the high-temperature working face,and field tests were carried out at the Dahongshan Copper Mine.The results showed that the mobile refrigeration technology could reduce the wet bulb temperature of the workplace to below 30℃,which meets the requirements of the "Safety Regulations for Metal and Non-Metallic Mines"(GB16423-2020).At the same time,a numerical model was established based on the field test,and the accuracy of the numerical simulation results was verified.(3)The influence of the air supply parameters of the mobile refrigeration equipment and roadway parameters on the cooling effect were analyzed.The results showed that the requirement of continuous operation could be achieved by adjusting the air supply volume under the test conditions.The optimal length of the cooling space was 15 m.The air supply temperature of the refrigeration equipment and the temperature of the roadway wall had a great influence on the dry bulb temperature and wet bulb temperature of the cooling space.The relative humidity of the supply air of the refrigeration equipment and the humidity coefficient of the roadway wall had a great influence on the wet bulb temperature and relative humidity of the cooling space.(4)A SET evaluation method for thermal comfort evaluation of miners was established.Combined with the theoretical basis of thermal comfort of miners and the evaluation index of thermal comfort of miners,the standard effective temperature SET was selected as the evaluation index of thermal comfort.Its calculation process was revised,and the calculation program of SET was written.Then,by carrying out parameter sensitivity analysis,it was concluded that the SET calculation program obtained in this paper was suitable for thermal comfort evaluation of most of the mines in China.(5)The thermal comfort of cooling space under the action of different air supply parameters of refrigeration equipment and roadway parameters was evaluated.The results showed that in order to provide a thermal comfort environment,the most effective measure was to reduce the supply air temperature of refrigeration equipment.At the same time,when the roadway wall temperature increased,the supply air parameters should be optimized to achieve thermal comfort.The research content and results of this paper have certain reference significance for the treatment of heat damage in the high-temperature mine working face,and provide a reference for the rational application of mobile refrigeration technology.