Characteristics, causes, and prevention measures of coal mine water hazard accidents in China

As one of the top “five major hazards” in coal mines, water hazards have become the second leading cause of danger for coal mine safety and worker lives, next only to gas accidents. Between 2000 and 2022, a total of 1206 water hazard accidents occurred in coal mines in China, resulting in 5018 deaths, among which 103 larger-scale events resulted in 2039 deaths. In order to identify accident patterns, summarize lessons learned, and promote prevention of water hazard accidents, various aspects were analyzed statistically, including geographical regions, years, seasons, hydrogeological types, water sources, and ownership of coal mines. Analyses revealed that the complexity of hydrogeological conditions highly correlated with the frequency of water-related accidents. Southern China recorded the highest number of incidents and casualties, and the peak incidence periods throughout the year mainly concentrated in March to May and July to August. Goaf water was identified as the primary source of water filling, which presented strong concealment and harm, mainly occurring in township-owned coal mines with weaker technical exploration and management capabilities. As for the causes of accidents, complex mining environments and insufficient attention subjectively, i.e., improper management and illegal mining, were the main reasons for accidents. Hidden water-bearing structures such as point-like collapse columns and linear fault structures, as well as goaf water that were not explored and placed in accordance with regulations, were identified as the main technical causes of accidents. By analyzing bibliometrics, it was found that current research themes focusing on coal mine water disasters align well with the principles of “predicting and forecasting, exploring if in doubt, exploring before mining, treating before mining”. To address the problems of “unclear risk assessment, inaccurate risk identification, and incapability to cope with accidents” in coal mine water disasters, corresponding countermeasures were proposed in three aspects: surveying filling factors and hidden geological factors causing disasters, analyzing three-dimensional hydrogeological conditions of filling water, and implementing an accurate classification source prevention. In response to the trend of informationization and intelligent development of water disaster prevention and control, technical measures such as transparent mines, water disaster monitoring and early warning, and emergency rescue were proposed.