Pumped storage hydropower in an abandoned open-pit coal mine: Slope stability analysis under different water levels

Many coal mines are being abandoned for economic and environmental reasons in China. The repurposing of abandoned open-pit coal mines into pumped storage hydropower (PSH) can help with the storage of renewable energy, improve mine environments, and provide added economic value. Construction of PSH plant will change the water level of the abandoned pit, which is envisaged as the lower reservoir, thus influencing the slope stability. In this study, the Fushun West Open-Pit coal mine was taken as an example. Borehole investigation and tilt photogrammetry were used to obtain the rock mass quality and volume of the abandoned pit. A natural lake, dumps, and another open-pit mine are envisaged as the upper reservoir, which could bring 40, 3,200, and 2,000 MW electricity installed capacity, and −295 m, −200 m, and −150 m water levels in the lower reservoir. The numerical analysis software GeoStudio was used for slope stability analysis considering the hydraulic effect under different water levels. A potential landslide risk may happen in several zones under specific water levels. Further imperviousness and reinforcement work is needed to guarantee slope stability for PSH plant construction in the Fushun West Open-Pit coal mine.