**13. Conclusion**

The Central European deposits were the first industrially mined uranium deposits in the world. Uranium minerals, especially uraninite (pitchblende), were noticed firstly by miners in the Ore Mts. area (Saxony, Bohemia) for a long time prior the uranium discovery. The uraninite was in this time found by miners in places with higher occurrence of uraninite, the silver and its minerals disapper. The first occurrence of pitchblende consequently entails trouble (pitch). The German chemist Klaproth in 1789 detected uranium by analysing pitchblende from the Johanngeorgenstadt uranium deposit in the German part of the Krušné Hory/ Erzgebirge Mts. In the nineteenth century, some chemists from silver metallurgical works in the Ore Mountains area, especially in Jáchymov, started with experiments using the yellow uranium–bearing components originated by processing of silver-uranium ores in glassmaking industry. Uranium glass became popular in the mid-nineteenth century, with its period of greatest popularity being from 1880s to the 1920s.

In 1896, A.H. Becquerel discovered the phenomenon of radioactivity. His student Marie Sklodowska-Curie recognised that pitchblende has higher radioactivity as pure uranium salts. Later, together with her husband P. Curie, they discovered two new elements: radium and polonium. In years 1908–1933, radium chloride from various uranium deposits, especially from the Jáchymov deposit was produced, for its use in medicine to produce radon gas, which in turn was used in cancer treatment. Later, radium was used for radon production. Highly radioactive mineral waters occurred in some localities in the Ore Mts. (Krušné Hory/ Erzgebirge) and were used to mitigate diseases of movement system such as rheumatoid arthritis, spondylitis, ankylosing spondylitis, condition after orthopaedic surgeries, diseases of peripheral nervous system and metabolic diseases. Radioactive water baths have been applied since 1906 in Jáchymov, since 1912 in Bad Brambach and since 1918 in Oberschlema, Saxony.

Otto Hahn and Fritz Strassmann conducted the experiments leading to the discovery of uranium's ability to fission and release binding energy in 1934. Lise Meitner and Otto Robert Frisch published the physical explanation in February 1939 and named the process "nuclear fission". The first use of nuclear fission in nuclear weapons applied at the end of World War II in Japan (Hiroshima, Nagasaki) started the first boom of exploration and exploitation of uranium ores in the whole world. The significant amount of uranium ores for producing the Russian nuclear weapons and nuclear power plants in the former Eastern Bloc was mined in East Germany (GDR) and Czechoslovakia. The total production of uranium ores in GDR from 1946 to 2012 was 219,626 t U. In Czechoslovakia, total uranium production from 1945 to 2017 was 112,250 t U. Some small amount of uranium ores after World War II was mined also in Poland (650 t U) and Hungary (21,000 t).

In the Czech Republic and East Germany, the exploration activities for uranium mineralisation were stopped between 1990 and 2004. In the Slovak Republic, Poland and Hungary, some small exploration activities on uranium mineralisation were provided between 2012 and 2014. Potential possibility of future exploration and mining of uranium ores is in the Central European countries recently blocked by various environmental and civil activities.
