Research on a reuse mode of geothermal resources in abandoned coal mines

The reuse of abandoned coal mines plays a vital role in the sustainable development of the mining in-dustry.Abandoned coal mines still contain abundant resources with potentially positive benefits,especially in the generation of large amounts of renewable geothermal energy,with great prospects for application.The paper ana-lyzed the current situation of geothermal resource exploitation and utilization in abandoned mines overseas and proposed a circulatory system model for geothermal resource utilization in abandoned mines by taking advantage of the water storage in the backward mining area after the roof collapse.Moreover,the system can make full use of geothermal energy,water and space resources in abandoned mines to produce clean energy,avoid waste of resources and disasters in abandoned mines,and effectively reduce greenhouse gas emissions and environmental pollution.The research results reveal that the water storage capacity of the goaf of a coal seam with a face length of 350 m,a strike length of 4 000 m,and a height of 6 m is 580 000 m³,and the static energy storage is 5 200 MW·h.Considering the temperature characteristics of different strata mining areas,setting up the cold and heat source reservoirs,the entire system can operate with a power of 8.4 MW,supplying the energy of about 24 960 MW·h per year and providing effective heating or cooling for about 250 000 m² of residential space.Compared to traditional fossil fuel coal,the system can reduce carbon dioxide emissions by approximately 7 812 t per year,with a carbon emission factor of only 0.072 kg/(kW·h),a reduction of more than 81%.In addition,some relevant departments should be established and the management of abandoned mines should be improved,and it should be make plans to reuse mines in advance of their closure.Also,it is important for the coal enterprises to maintain the appropriate technical resources to facilitate the reuse of the abandoned mines and promote the environmental and economic recovery in the mining regions.