A New Method for Evaluating Radionuclide Migration in Groundwater

Abstract

ABSTRACT: The purpose of this study is to propose a new method for evaluating the migration of nuclides of uranium tailings paste backfill in groundwater. Uranium tailings reservoir is a significant threat to the nearby environment and the health of residents. Filling the uranium tailings paste backfill into the mine goaf can effectively reduce the impact of uranium tailings on the surrounding environment. However, there is still a lack of effective methods to evaluate the effect of radionuclides in uranium tailings paste backfill on groundwater. Uranium tailings paste backfill was made from the samples collected from a uranium tailings reservoir, and leaching experiments were carried out to obtain a variation curve of uranium concentration. The fractal parameters of rock fractures are obtained from the goaf of a gypsum mine exploration. The discrete fracture network model (DFN) of underground rock mass in the goaf is established according to the fractal parameters. When the results of leaching experiments are introduced into the numerical simulation model, it is found that when the local water is in the flow state, the flow direction of uranium is consistent with that of groundwater and is related to fractures. 1. INTRODUCTION Mining is extracting underground resources and can be divided into open-pit and underground mining depending on the mining method. The mining process generates a large volume of tailings and void areas and releases hazardous substances into the surrounding environment. The threat to the surrounding environment from tailings and voids does not end with mining (Yilmaz and Yumlu, 2017). The pollution of the surrounding environment by tailings, especially uranium tailings, is obvious. Although uranium in uranium tailings has been extracted, there are still a lot of harmful substances in the tailings. These harmful substances can be carried into the environment by dust and groundwater and enriched into the human body through the food chain, posing a threat to human health. What’s more, the dams of uranium tailing reservoirs may be destabilized by extreme weather or seismic activity, and a large volume of tailings in the ponds may break through the constraints of the tailings dams under gravity, with disastrous consequences for the lives of the surrounding residents and the environment.