Investigation and comprehensive utilization of resources in closed coal mines in Anhui Province, China

[Objevtive] With the continuously intensive exploitation of coal resources and the structural reform of energy supply, many coal mines in Anhui Province have been closed due to resource depletion or backward production capacity. However, the closed coal mines still host resources such as underground spaces, residual coals, gas, mine water, land, and infrastructure equipment. Hence, reutilizing resources in closed coal mines holds significant engineering value and economic benefits. [Methods] Based on the general information and reutilization status of 59 coal mines in Anhui Province that have been closed since 2013, this study analyzed the distribution characteristics, residual resources, and reutilization potential of these coal mines. A database and a WebGIS cloud platform were developed for these closed coal mines, allowing for their information search, analysis, and visualization. This study explored the Pan-1 and Shitai coal mines as examples, presenting schemes for reutilizing the closed coal mines through residual gas drainage and semi-underground pumped storage. [Results and Conclusions] Key findings are as follows: (1) The closed coal mines in Anhui Province are primarily distributed in the Huainan and Huaibei areas. Some of them feature relatively short closure durations, abundant residual resources, and clear property rights, demonstrating the considerable potential for resource reutilization. (2) For the closed Pan-1 Coal Mine, the implementation of the 3D residual gas drainage technique that combines sealed-wall pressurized drainage, drainage using original boreholes, and drainage through surface drilling enables integrated engineering involving drainage, gas drainage, and resource utilization within the goaf of the closed coal mine while ensuring the safe production of adjacent mines. Consequently, the Pan-1 Coal Mine yielded cumulative gas drainage of 4 840 × 104 m3 and power generation of 8 590 × 104 kW·h within three years, corresponding to direct economic benefits of 5 120 × 104 CNY. (3) For the closed Shitai Coal Mine, its underground space can provide an effective storage capacity of 30 × 104 m3, making it possible to transform into a semi-underground pumped storage power plant with an installed capacity of 35 MW. The case analyses indicate that some of the closed coal mines in Anhui Province manifest technical and economic feasibility in resource reutilization, and further research is required. © 2024 Science Press. All rights reserved.