Numerical simulation of water flow in a large waste rock pile, Haizhou coal mine, China

Abstract

Waste rock is the large volume of broken rock and low grade ore materials tend to create potential problems, such as acid mine drainage (AMD), leaching of heavy metals, and slope stability problems. These problems are related to the flow of water through the waste rock. In this study, long term numerical simulations of unsaturated flow in a large waste rock pile are conducted to investigate the effect of internal variability in water flow and saturation. The approach first consists of a basic geotechnical properties investigation to define the main features of the pile. This is followed by numerical simulations of the unsaturated flow through the pile based on the results from the field and laboratory characterization. The simulation results showed that pile is unable to fully saturate and drain during the simulated period. It was also found that high evaporation and the high bottom flux rate and also coarse grain nature of waste rock materials results holding few amounts of water in the system.