Use of tracer to study the interaction between groundwater and surface water in the coal region of Santa Catarina, Brazil

Abstract

This article deals with the use of tracer as a tool to demonstrate the interconnection between groundwater from an underground coal mine abandoned with surface water of a pond and along a geological fault. The tracer used was Rhodamine B, a soluble organic compound in water, which serves for the determination of flow and flow directions in karst aquifers and may be detected colorimetrically or by fluorescence. It was built a tubular shaft that reached the gallery of abandoned mine and it was injected Rhodamine B. It conducted a pumping test in the well to determine the hydraulic conductivity in the fractured rock. The hydraulic conductivity showed that the tracer would take 5 days to reach the monitoring point in Lingua do Dragão Lagoon. For safety measures, the monitoring started on the 4th day after the injection of Rhodamine B. The method proved to be very efficient and conclusive. It was possible to establish the interconnection between the groundwater of the underground  mine and the lagoon waters, as well as the flow of groundwater from the mine galleries by fault, reaching another existing tube well. This is a methodology that can be used in abandoned underground mines, as well as in fractured aquifers, for flow studies and interrelationship between groundwater and surface water.