Progress Report on the Wismut Decommissioning Project at the Flooded Konigstein Uranium Mine

摘要

Prospecting for uranium began in the Upper Cretaceous sandstones of the Elbe river valley southeast of Dresden in 1961. Systematic mine operations commenced 1964. As a response to low and decreasing ore grades alternatives to conventional mining were precociously searched for. Development of in-situ leaching technology started at the end of the sixties leading to a changed exploitation method using sulphuric acid. Uranium mining (exploitation) was terminated at 31st December 1990. Accompany-ingtothe physical underground remediation operation including closure of mine workings and removal of technical equipment and installations comprehensive R&D-Efforts were carried out for preparation of the mine flooding. Flooding of mine sec- tion I - up to 140 m a.s.l. - started January 2001. Since January 2013, the water level is maintained in the flooded mine at 139.5 m a.s.l. by continuous pumping. About two thirds of the volume of mine workings and pore space is flooded at present. Wismut GmbH, Chemnitz/Germany, intends to continue the flooding to the natural level of groundwater. The permitting procedure - initiated in December 2011 - is still pending. Currently, technical discussions with respect to potential scenarios and connected risks with authorities are conducted. As a result, Wismut applies for a hydraulic test end of March 2017 to obtain basic data for prediction of hydrological and geo-chemical conditions as result of a further flooding.