ABSTRACT

The polymetallic Niederschlema/Alberoda uranium deposit in the Saxonian Erzgebirge (Ore Mountains) has been flooded since 1991. The objectives of the tests were to investigate the quality and rate of flow within a large part of the flooded mine to predict the mass flow of the pollutants. Based on the results of a first tracer test with Lycopodium clavatum in mid 1992 a second one was conducted at the end of 1995.

Four insertion and two sampling points were chosen and at each sampling point up to 800 g of coloured spores were inserted by using a newly developed insertion apparatus: LydiA (Lycopodium Apparatus). Beginning one day after insertion, at each sampling point two samples per weekday were taken. Out of the 15 samples an aliquot amount of material was counted and resulted in a reasonable good recovery rate of 2%.

It could be shown, that the mean speed of the mine water within the investigated part of the mine ranges between 3 and 8 m min−1 and that the different parts of the mine are hydraulically well connected with each other. Therefore it may be that the pollutants within the flooded mine are transported by convective flow resulting in an exchange from deeper parts of the mine into higher ones.