Abstract: Deep mining has become the development trend of underground mines. With the increase in mining depth,
high-temperature thermal hazards in underground mines have become increasingly prominent,which not only affects the physical
and mental health of operators,but also reduces the operational efficiency of personnel and equipment operations. Therefore,
scientifically and accurately evaluating the degree of underground heat damage has become a necessary prerequisite and
key link for carrying out deep well heat damage control. A comprehensive evaluation model for deep well heat damage based on
the theory of unascertained measures is proposed to address the distortion of evaluation results caused by uncertainty factors in
the evaluation process. Firstly,on the basis of heat source analysis and heat calculation,a comprehensive evaluation index system
for thermal hazards was constructed from three dimensions:objective conditions,intervention measures and subjective perceptions.
Secondly,the classification of deep well thermal hazards levels and evaluation index system indicators was determined,
and the combination weight calculation of fuzzy analytic hierarchy process-entropy weight method was completed using
grey correlation analysis method. Finally,the unascertained measurement theory was introduced to construct a comprehensive evaluation
model for deep well thermal hazards based on the unascertained measurement theory. The calculation of unascertained
measurement vectors at different levels of the evaluation system was completed,and the comprehensive unascertained measurement
vector of the evaluation target was finally obtained. The confidence criterion was used to complete the thermal hazards evaluation.
The model was applied to complete the thermal hazards evaluation of different working faces in a certain underground
mine in China,and the degree and changes of thermal hazards in each working face was obtained. The research results have addressed the uncertainty problem of deep thermal hazards factors and evaluation scales,achieved a comprehensive evaluation
combining qualitative and quantitative,subjective and objective approaches,and effectively improved the accuracy and scientific
validity of the evaluation results.

Key words: metal mine,deep mining,thermal hazards evaluation,unascertained measure theory