Research Progress on the Resource Reutilization of Closed/Abandoned Coal Mines Under the Dual Carbon Strategy

Under the dual carbon strategy and ongoing coal capacity reduction, the closure of many coal mines has led to idle resources and rising environmental risks in mining regions, creating an urgent need for reuse approaches that support green and low carbon transition. Abandoned and closed mines contain substantial underground space, mine water, geothermal energy and residual gases, which provide opportunities for underground energy storage, low enthalpy geothermal development and regional water regulation. However, resource exploitation is constrained by geological structure, the condition of mine workings, rock mass stability and hydrogeological connectivity, and the associated engineering safety, economic viability and environmental impacts remain insufficiently understood. This study reviews research progress on the reuse of abandoned mines in terms of energy storage, geothermal utilization, graded mine water use and residual gas extraction. The structural conditions and key control parameters of systems such as UPHS, CAES and GES are summarized, along with the heat transfer and recharge processes of open loop, closed loop and hybrid geothermal systems. The transition of mine water utilization from simple discharge to differentiated use, regulation and ecological enhancement is also outlined. Based on typical application scenarios, a framework integrating permanent and transitional constraints is proposed, and major challenges including limited resource characterization, incomplete technical systems, high engineering uncertainty and weak policy coordination are identified. The review shows that abandoned mines have significant potential for energy utilization and underground energy storage, while large scale implementation requires advances in deep rock mass coupling mechanisms, sealing and stability evaluation, long term monitoring and integrated multi energy systems. This work provides a reference for the comprehensive reuse of abandoned and closed mines and supports low carbon transformation in mining regions.