Risk grading method and application for mine thermal environment based on enthalpy

High temperature heat damage is one of the prominent disasters in deep mines, which seriously restricts the safe and efficient production of mines, and scientific evaluation of mine thermal environment is the basis for solving the problem of mine heat damage. Based on the human heat exposure test in high temperature and high humidity environment, the enthalpy method of mine thermal environment evaluation was proposed, the evaluation standard of the enthalpy method was established, and the risk level of mine thermal environment was divided, which was applied in the 1070 excavation face of Haishiwan Coal Mine. The results show that the enthalpy value has a good ability to characterize the thermal response of the human body, which can not only comprehensively reflect the high temperature and high humidity environment of the mine, but also can be directly used in the design of cooling capacity during mechanical refrigeration and cooling, and has good applicability in the mine heat damage control of deep mines. Taking the enthalpy values of 40 kJ/kg, 55 kJ/kg, 70 kJ/kg, 85 kJ/kg and 100 kJ/kg as the thresholds, the thermal environment of the mine was divided into five levels, including no risk, low risk, medium risk, high risk and very high risk, and the human thermal response and counter measures under different risk levels of thermal environment were clarified. The thermal environment of the 1070 excavation face of Haishiwan Coal Mine has the characteristics of high temperature and low humidity, and the lowest thermal environment risk level is medium, and the local area is high risk or very high risk level. Mine air conditioning plays an important role in the key control areas of thermal environment, but the cooling capacity still needs to be further increased. The actual situation of the 1070 excavation face is highly consistent with the evaluation results of the enthalpy method of thermal environment, which can reflect the influence of high temperature and high humidity environment on the comfort of underground operators, and verify the applicability of the enthalpy method.