Analytical method of reservoir capacity of underground reservoir in coal mine: a case study

Modern mining within ecologically fragile areas is under enormous pressure from the ecological and geological environment. Using abandoned coal mine as the underground water reservoir is provided an effective thought for weaken eco-geological risks in mining district. Accurate estimation of reservoir capacity is conducive to guide the construction of underground water reservoir. In this paper, the estimation models of underground water storage capacity were established, which divided into two kinds: horizontal mining district and inclined mining district. Furthermore, the minimum porosity of broken rock mass was analyzed based on the laboratory experiments, and the fitted equation of minimum porosity was developed. A modern coal mine in northwest China was taken as an example, the feasibility of proposed model was verified by in-situ measurement. Finally, the effect of porosity of broken rock mass, water storage height and coal seam dip angel on water storage capacity were presented. The coal seam dip angle should be the principal considerations in choosing the site of underground water reservoir.