Impact of Tailing Dams on Land and Water Environments Makeng Underground Iron Mine, China

摘要

A recent study was carried out around three tailing dams (2 previous and one in operation) in order to determine the impact of tailing from iron ore processing on land and water in the Makeng Underground Iron Mine. The survey focused on the content of sulfate, iron, calcium, bicarbonate, copper, sodium and magnesium in 50 samples of soil, tailing and water (surface and ground water) from 22 different sampling stations distributed around the three dams, together with electrical conductivity and hydrogen potential. The research set out to compare the samples from downstream sampling stations with samples from reference points and samples from upstream sampling stations, relative to each tailing dam, in order to identify the effect of the impoundment on the environment. The research also aimed to compare the tailing sample results between one impoundment to another in order to understand the migration over time of substances from the dams to land and water and to control acid drainage. The research result revealed that the concentration of elements contained in the samples from downstream stations affected by tailing dams is slightly higher than those from reference points and upstream stations that were not affected by tailing. The pH and EC value from downstream areas were also slightly higher compared to those from upstream areas. The result also revealed that EC from the tailing sample from the oldest dam (abandoned 20 years ago) was significantly lower than that obtained in tailing samples from the previous dam abandoned three years ago. The sulfate concentration in the tailing samples from the 2 previous dams were significantly higher than sulfate concentration from tailing samples obtained from the new dam currently in operation. The data made it possible to infer that the tailing in the Makeng Iron Mine had little impact on water and land, which can be explained by an increase in the pH and substances above the background level in the areas affected by the tailing storage.