1. National data 2011-2020 [Online]. National Bureau of Statistics. Available: https://data.stats.gov.cn/easyquery.htm?cn=C01 [Accessed 2 August 2021].
2. Geological problems in underground coal gasification;Qin;J China Coal Soc,2019
3. Lu G. Research on residual coal workability evaluation and remining technology of aged coal mine. China University of Mining and Technology. Doctoral thesis. Xuzhou. 2010.
4. Economic benefit analysis of “Under Three” coal mining;Xing;Coal Econ Res,1985
5. Yuan Y, Tu S, Wang J, Feng J, Wang Y. Research and design of residual coal mining technology in goaf of aged mine. 2007 academic annual meeting of Mining Professional Committee of China Coal Society. Datong: China University of Mining and Technology Press, 2007.