Damage Features and Formation Mechanism of the Strong Water Inrush Disaster at the Daxing Co Mine, Guangdong Province, China

The largest water disaster in the history of coal mining in China with respect to maximum water inrush quantity (≈ 13,600 m 3 /min) occurred at the Daxing underground mine in 2005. Triggered by accumulated water in a higher-level, mined out (goaf) area, it caused great damage, including 121 deaths and direct economic losses of over 47 million yuan. Damage to the roof and floor rock caused by mining-induced redistribution of ground stress is believed responsible for the caving of the roof and the subsequent inrush, though accumulated water in the goaf area, the weight of the roof pillar, fractures due to minor faults, the comprehensive influence of groundwater, including the pore water pressure and the water’s chemical action, and the steeply inclined coal seam all contributed to the scale of the disaster. The inrush site was located near a fault and had been observed as an anomaly during geophysical testing. Recommendations made based on this tragedy include: mining of steeply inclined coal seams beneath water bodies must be forbidden due to the lack of effective mitigation measures; the integrity of waterproof pillars must be a major priority; and underground mining requires a thorough understanding of hydrogeological conditions, which must be regularly updated through the mining process.