Review and development status of filling coal mining technology in China

Coal mine filling mining technology plays a pivotal role in solid waste disposal,control of coal mining subsidence,improvement of resource recovery rate and construction of ecological mines.Since the beginning of the 20th century,the world’s mine filling and mining technology has a century of development history.According to data analysis and the types of filling materials,the filling mining technology in the 20th century experienced four development stages:dry waste filling,water sand filling,low-concentration tailings cemented filling and paste filling.The filling coal mining technology of China at that time,the application and development process of the main filling process such as water sand filling and gangue self-sliding filling were reviewed.Since the 21st century,China’s backfill mining technology has achieved rapid development,forming three types of filling materials:solid,paste,and ultra-high water,and two types of filling technologies applied to fully-mechanized and continuous mining faces.The types of solid waste utilization,the filling effect,the degree of mechanization,and the overall technical level have been greatly improved.The filling materials and their preparation and transportation,and the characteristics of the filling process of the working face were summarized.In particular,the characteristics of the filling of the fully-mechanized mining face and the production efficiency constraints were analyzed.It is proposed to reduce the time of various filling links in terms of new equipment research and development,temporary roof protection technology,and efficient sealing measures for filling spaces.Finally,combined with the practical results,from the aspects of filling coal mining capacity,surface subsidence coefficient,cost of filling mining,resource recovery rate and technical application conditions,five types of filling coal mining methods including comprehensive mining with solid filling,comprehensive mining with paste filling,comprehensive mining with ultra-high water filling,solid filling continuous mining and paste filling continuous mining were analyzed.This provides a basis for each mine to choose its own filling method.