Abstract:
Against the backdrop of China’s strategic advancement from shallow to deep exploitation of metal mineral resources and the escalating thermal challenges inherent to deep mining, this study provides a comprehensive review of recent progress concerning geothermal environment characteristics, thermal hazard mitigation technologies, and integrated mining-thermal co-extraction strategies for deep metal mines. The heterogeneous and stepped heat transfer characteristics of deep mine geothermal systems resulting from the combined effects of natural geothermal heat sources and anthropogenic thermal inputs are elucidated. The stepped heat transfer mechanisms, characterized by multi-source driving, multi-phase transport, and multi-mode coupling, are systematically analyzed, along with their combined influence on surrounding rock stability and underground roadway thermal regimes. Adopting a holistic governance framework centered on "source control, environmental regulation, and individual protection," this study summarizes key technological advances and their corresponding applicable conditions in the control of thermal sources from surrounding rock and groundwater, intelligent ventilation integrated with multi-stage refrigeration systems, and personal cooling protective measures. The evolving trends in thermal environment management for deep mining operations are also critically reviewed. Building upon these discussions, three archetypal models of mining-thermal co-extraction are synthesized, namely, heat exchange via mine water circulation, heat recovery from goaf zones, and in-situ rock mass modification. The influence of coupled thermo-hydro-mechanical-chemical (THMC) multiphysics interactions on the long-term stability and energy efficiency of mine geothermal systems is explored, and a system optimization paradigm is proposed, emphasizing "solid-controlled flow, flow-mediated heat transfer, heat-activated reactions." Finally, a multi-constraint control and multi-objective optimization framework for mining-thermal co-extraction is developed, which balances thermal hazard mitigation effectiveness, energy utilization efficiency, operational safety, and economic feasibility. This framework offers a crucial technical reference for facilitating the transition in deep metal mine thermal management from passive cooling methodologies toward active temperature regulation and synergistic energy exploitation.