Mine water chemistry development in the R3 shaft of the Rozna I uranium mine, Czech Republic

Abstract

The paper describes the current non-mining state of the Rozna I uranium mine which is located in the central part of the Czech Republic. The subject is a 1 200 m deep R3 shaft which is excavated from the surface. At the R3 shaft is carried out regular monitoring of mine water, specifically inflows to the deposit and their chemistry. Chemical monitoring is carried out by proper collection of mine water and their consequent chemical analysis in an accredited laboratory. The results of the chemical analysis were processed using standard text and spreadsheet editors and using geochemical modeling software. The paper defines several types of water with slightly different chemistry, but the majority is calcium sulphate type of mine water. Occasional fluctuations in mine water concentrations were not dependent on the concentration of extraction, because at the R3 shaft was extraction of uranium ore terminated in 1996. Fluctuations are attributed only to technological interventions of maintenance work on the shaft. The development of chemistry of mine water was described at the shaft during the years 1994 – 2019. The mine water from the R3 shaft were analyzed for the saturation index. Minerals which could precipitate under specific conditions in the form of amorphous precipitates, coatings or other precipitates, were described.