Multi-criteria risk assessment of thermal comfort in deep underground mines: an integrated evaluation framework and case studies

With mining activities extending to greater depths, thermal hazards have become a critical risk factor affecting miner health and operational safety. To systematically assess the thermal risks of miners in underground mining, an integrated multi-criteria evaluation framework is developed. It incorporates three quantitative and seven qualitative indicators, with hierarchical weights assigned through the Analytic Hierarchy Process (AHP). Then, the measurement values of the indicators were calculated using the linear measurement function (LM), sinusoidal measurement function (SM), parabolic measurement function (PM), and exponential measurement function (EM). The comprehensive risk assessment is conducted using the credibility degree recognition (CDR) criterion and the maximum membership (TMM) criterion. By coupling the four functions with the two criteria, eight alternative evaluation methods are formulated. Furthermore, the applicability of the proposed framework is validated through case studies of three deep mines, showing that thermal comfort risks can be reliably quantified and compared. Among the eight alternative evaluation methods, LM-CDR and SM-CDR were identified as the most robust approaches. The proposed framework provides a scientific basis for risk-informed decision-making and practical guidance for thermal hazard prevention, thereby supporting safe and sustainable deep mining operations.