Hydrogeological Investigation for the Assessment of Spring Pollution Due to Abandoned Mines in a Karst Area

Abstract

This paper presents a hydrogeological investigation case study for assessing the sources and pathways of spring pollution in a karst area in Guizhou Province, Southern China. Our methods included hydrogeological surveys, geophysical surveys, cave detection, tracer tests, and borehole drilling. The results showed that the pollution of the Longdong Spring is controlled by the amount of rainfall, which also determines the duration of pollution. The concentration of Fe and Mn ions in the spring was found to exceed that in the code for drinking water quality (China) by more than 300 times. The investigations showed that the source of the pollution is the mine water drainage from the abandoned Feilong coal mine, which is located to the northwest of the Longdong Spring. The drainage to the spring was found to occur 24 h after the groundwater level in the goaf reached approximately +908 m above sea level. This indicates a recharge pathway between the abandoned mine and the Longdong Spring. Recommendations for grouting around the spring and sinkhole for pollution control are put forth.