Impact of water accumulation in abandoned mines on adjacent production mines

The goaf water accumulation of abandoned mine will damage the strength of boundary coal pillar, cause coal pillar failure, and pose a threat to the safety of adjacent production mine. The research on the safety limit of goaf water level after mining damage of coal pillar at mine boundary is not comprehensive. In order to solve the problem, taking East Shaft of Shuoshi Mining Industry of Huaibei Mining Group(Shuoshi East Shaft) and Huaibei Shuanglong Mining Co., Ltd.(Shuanglong Company) as the research objects, this paper analyzes the impact of goaf water in abandoned mine of Shuoshi East Shaft on Shuanglong Company, and puts forward corresponding water disaster prevention measures. The mining damage of coal pillar at mine boundary is studied by theoretical calculation and numerical simulation, and the safety limit of goaf water level is calculated according to the damage results. Based on the Bernoulli equation and the Darcy-Weisbach pipeline flow theory, the drainage capacity of the existing drainage boreholes is calculated and the safety is evaluated. The research results show that under the impact of mining, the damaged width of coal pillar at the mine boundary is about 19 m, the effective width is only 21 m, and the maximum water level difference that can be borne is 33 m. When the water level in the abandoned mine of Shuoshi East Shaft rises to −398 m, the coal pillar may be unstable. The drainage capacity of the existing drainage boreholes in the mine is about 89 m³/h, which is less than the actual abandoned mine water inflow of 160 m³/h. After reaching the limit water level, the goaf water level may continue to rise, and there is a threat of water disaster. The water disaster prevention and control measures such as enlarging the borehole diameter and adding drainage boreholes are proposed. The research results can provide reference for the water disaster prevention and control of abandoned mine under similar conditions.