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Old closed uranium mines can be a significant source of environmental pollution and hazards to human health. The problem could become more severe in time due to erosion if the restoration measures are not properly maintained. There are many uranium mines in Bulgaria that, even closed in the 1990s, could be a pollution source for surface and groundwater in their region. Through hydraulic connections, they can contaminate the rivers passing nearby. The aim of the present work was to check the hypothesis of a possibl...

The ore extraction from Krumovo deposit, located at the northern periphery of the Manastir heights in Southeast Bulgaria started in 1906 and continued till 1986. The ore comprised Fe3O4 with admixtures of sulfides such as pyrite, pyrrhotite, marcasite and chalcopyrite. Open pits and underground workings were used. The excavations severely degraded the habitats, vegetation and waters on an area of about 3 km2. By 1986 waste rock (comprising hydrothermally altered basic magmatic rocks, such as gabbro or diorites, ma...

The paper describes results from 18 months data collection and analogue modeling of “rain water – calcrete” interaction. The expe riment is based on leaching by natural rain and snow-melting water of material from diff erent soil and undersoil layers, containing various amounts of carbonates. It confirme d that rain and snow-melting water, circulating through the soil, undersoil and the underlying rocks, dissolves calcium rich minerals. Under dry weather and relativel y high temperature the hydrogen carbonat...