Status and research progress for fine remining of residual coal in the failure zone of small mines

China’s early backward mining method of small mines left a large amount of unmined coal resources.Fine remining of residual coal resources is of great significance to effectively recover precious coal resources, extend the service life of mines, promote the sustainable development of the coal industry, and ensure national energy security.This paper focuses on the key scientific and technical issues involved in the fine re-mining of residual coal resources in the failure zone of small mines and reviews the current status and research progress of residual coal resources mining in China.The results show that the method of combining geophysical exploration and drilling is an important way to find out the characteristics of residual coal resources.The complex stress environment in the failure area zone of small mines led to abnormal ore pressure in the process of residual coal recovery.The reasonable recovery mode and surrounding rock control method should be matched with the broken roof and caving form of the coal seam in the failure area of small mines.The strengthening of the monitoring and control of major hazards such as harmful gases, water and spontaneous combustion in the failure zone of small mines is an important guarantee for the safe and efficient recovery of residual coal.In the follow-up, it is necessary to strengthen the systematic research on the detection technology of toxic and harmful gases in the goaf area, the law and mechanism of abnormal mine pressure in the failure area of small mines, the new model of residual coal remining, the new technology of surrounding rock control, and the new prevention and control method of residual coal remining disaster.