Hydrogeochemistry of groundwater seepage into an acidic mining lake

Abstract

In the Lusatian Lignite Mining District 259 mining lakes (ML) are originating from abandoned mines. They show significant differences in their morphometry and are mostly strong acidic (HEMM et al. 2002). The oxidation of sedimentary pyrite in aerated dump sediments (tertiary sands) forms acid mine drainage rich in iron and sulphate which is still present after filling the pit and has decisive influence on matter flux, biocoenotic development and possible uses, e.g. recreation or water supply (UHLMANN et al. 2001).Mining lakes are groundwater dominated hydrological systems (HOFMANN et al. 2004). During the last three decades the approach of seepage meters was mainly established in shelf regions of oceans, estuaries or lakes to quantify groundwater flux (LEE 1977, BOYLE 1994, BURNETT et al. 2002). But only a few usages of seepage meters are known from acidic mining lakes (BOZAU et al. 2000, WEBER 2000).The main purpose of this study was to investigate the interaction of acid mine drainage with the sediment by using seepage meters. Therefore, ML Plessa 117 was chosen as a typical example of mining lakes in geological, hydrogeological and hydrological devastated areas.