**6. Discovery of radon and origin of radon spas**

(Harrachov in the Czech Republic and Szklary in Poland) and in the South Bohemia (Lenora, Josefsthal near Zvonková). A glassmaker from the Nový Svět near Harrachov developed and on the fair in Prague (1831) presented new, partly opaque uranium "Chrysoprasglass" [5].

Production of uranium glass was popular also in the other European countries, especially in Great Britain, France and Germany. In the Great Britain, it was glassworks in London (White friars) and Sturbridge area (Thomas Webb glasswork). In France, the first uranium glass was produced in glasswork Choisy-le Roi in Paris in 1838. The uranium glass in France was later

The highly different uranium glass products produced by glassworks in the North and South Bohemia mainly pressed glass cups and polished vases and were very popular souvenirs sold predominantly in the West Bohemian health resorts (Karlovy Vary, Mariánské Lázně, Františkovy Lázně) [2]. These glass products from the uranium glass were very important

In 1895, W.C. Röentgen discovered new rays, later named as the "Röentgen rays". One year later, in 1896, A.H. Becquerel (1852–1908) discovered the phenomenon of radioactivity by exposing a photographic plate to potassium uranyl sulphate. He determined that a form of invisible rays emitted by uranium salts had exposed the plate. His student, Maria Sklodowska-Curie (1867–1934), recognised that some samples of pitchblende, including pitchblende from the Jáchymov uranium deposit, have a higher radioactivity as pure uranium salts. Marie and Pierre Curie (1859–1906) discovered the new element radium, in the form of radium chloride, in 1898. They extracted the radium compound from residues originated by production of uranium colours in the Jáchymov factory. For first experiments of both researches in 1898, they obtained from the Jáchymov uranium colour factory 5 kg of these residues, later 100 kg of these residues. In these residues, Marie and Pierre Curie discovered along with radium a second new element, polonium [6, 7]. For isolation of both new elements, both researchers in 1899 obtained from the Jáchymov factory 1000 kg of residues. These residues were collaborated in bigger laboratories of the Société Centrale de Produits Chimiques in Paris [8]. In 1910, radium was isolated as a pure metal by M. Curie and A. L. Debirne thought a radium chloride electrolysis. Radium metal was first commercially produced in the beginning of the twentieth century by Biraco, a subsidiary company of Union Miniere du Haut Katanga in its Oolen plant in Belgium. In the Jáchymov uranium colour factory, radium chloride was produced from 1908. In the years 1909–1937, the Jáchymov factory produced 64.3 g of Ra. In years 1908–1933, radium chloride was produced for its use in medicine to produce radon gas, which in turn was used in cancer treatment. In 1934, the Jáchymov uranium factory started producing self-luminous paints for watches, aircraft switches, clocks and instrument dials. The total production of

uranium ores from the Jáchymov ore deposit in years 1853–1945 was 469.5 t of U [9].

After the isolation of radium by Marie and Pierre Curie from pitchblende from Jáchymov, several other scientists started to isolate radium in small quantities. Later, some small companies

utility products of the Biedermeier and Art Nouveau periods.

4 Uranium - Safety, Resources, Separation and Thermodynamic Calculation

**5. Discovery of radioactivity, radium and polonium**

named as "Cristal Dichroide".

Ernest Rutherford and Robert B. Owens discovered radon in 1899. In 1900, Friedrich Ernst Dorn in some experiments found that radium emanates a radioactive gas, which was named radium emanation. Later, similar emanations for thorium and actinium were found, which were named as radon, thoron and actinon [10, 11].

The danger of high exposure to radon in silver-uranium mines has long been known. Georg Agricola, physician in Jáchymov, recommended ventilation in mines to avoid this mountain sickness (Bergsucht). In 1879, this condition was identified as lung cancer by investigation of miners from the Schneeberg silver-uranium deposit in the Saxony [12]. The first major studies with radon and health were performed in the context of uranium mining in the Jáchymov ore deposit [13, 14]. Recently, a detailed study of the influence of radon on miners' health in the Czech uranium mines was published by Řeřicha et al. [15].

Exposure to radon, a process known as radiation hormesis, has been suggested 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 [16–18].

Radioactivity of the first radioactive water springs in the Jáchymov mine Werner was measured by Austrian physicists Heinrich Mache and Stefan Meyer in 1905. They found higher radioactivity (2.5 kBq/l) [19]. These results started Jáchymov spa history. The first spa house was opened in 1911 (recently spa centre Agricola). In year 1912, a luxury spa house Radium Palace was opened. During years 1908–1924, the Štěp springs from the Werner mine was used for radon bath therapy. In 1924, spring Curie at the 12th level of the Svornost mine (30 l/min, 29°C, 5 kBq/l) was found. After closing uranium mining in the Jáchymov area, in 1960–1962, new hydrogeological exploration of radioactive springs at the 12th level of the Svornost mine was performed. Two new radioactive water springs were found (H-1 and HG-1 – Běhounek, 300 l/min, up to 36°C, 10 kBq/l). More recently performed hydrogeological exploration was found in 2000 spring Agricola (10 l/min, 29°C, 20 kBq/l) [20–24].

In Bad Brambach, a new spring of radon water was found by Max Weiding in 1911. The high radioactive water spring was later named Wettinquele and was used for radiotherapy from 1915 and represented a mineral water spring with the highest radioactivity in the world (26 kBq/l). The radon spa in Bad Brambach from 1945 to 1948 was used as nursing home for the Soviet arms and since 1949 is used as a spa for all patients with diseases of movement system [16].

Today, the community of Bad Schlema is an amalgamation of the formerly separate communities of Niederschlema and Oberschlema. After rich radon springs were opened in the Marx-Semler gallery in Oberschlema between 1908 and 1912, the world's richest radium spa developed after 1918. Ten years later, it was counted among Germany's most important spas. Once the uranium mining was taken over by the Soviet occupation forces, the spa and the downtown of Oberschlema were utterly obliterated. After uranium mining came to an end in 1990, the mayor, Konrad Barth, organised Schema's revival as a spa town, which was realised in 1998 when the new "Spa house" (Kurhaus) was opened. The newly opened radon springs afforded ample bathing. In 2005, Saxony's state government bestowed upon the community official designation "Bad", after it had already been recognised as a radon spa since 2004 [18, 25].

extension of exploitation of radium-bearing uranium and concentrates in Czechoslovakia and their delivery to the Soviet Union" was signed. The Memorandum contained also an attachment, which proclaimed this document to be highly confidential. According to the Memorandum, the Joachim Mines State Enterprise was founded. Leading posts in this enterprise were taken over by the Soviet experts. The Memorandum, however, did not specify the costs of exported uranium ores. This problem was progressively discussed between 1949 and 1952 [28]. In 1945, the Jáchymov ore deposit represented the only available uranium source on the territory of the Soviet block where uranium ores could be exploited immediately. In East

History of Uranium Mining in Central Europe http://dx.doi.org/10.5772/intechopen.71962 7

From 1945 to 1949, in the Jáchymov uranium mines, the German war prisoners started to work, who were later replaced mainly by political and other Czechoslovak prisoners. The Jáchymov together with Horní Slavkov and Příbram became known as parts of the "Czech Gulag". In Jáchymov, 65,000 prisoners worked in concentration camps until 1961 [9]. For following exploration of uranium deposits on the Czechoslovak territory, in 1946, "Prospective geology group", which later evolved into the independent organisation, was established. Thirty Soviet geologists formed the nucleus of this group, and according to territorial responsibilities, the group was subdivided into seven subgroups. During 1948 and 1962, the Horní Slavkov uranium deposit was opened and exploited. In the Czech part of the Ore Mts. (Krušné Hory/Erzgebirge), some smaller ore occurrences and deposits (e.g., Potůčky, Abertamy) were

In the first stage of uranium exploration, the selected territories according to older geological studies and geological mapping were covered in 1958–1964 by emanometry, sampling from a depth of 1 m. Productivity of three-personnel groups was about 300–500 holes per day. Productivity of later used technique with 3 m holes was much lower, and with this technique, only limited areas were covered. Some other geophysical methods that were used for exploration of uranium deposits were ground and car-borne gamma-ray survey [30]. From 1946 to 1955, exploration for uranium ores was concentrated on the known vein deposits in the Ore Mts. area (Jáchymov and Horní Slavkov) and area of the known base-metal vein deposit Příbram. During systematic emanometry and gamma-ray surveys, a new type of hydrothermal uranium deposits evolved in mineralised shear zones (Rožná, Olší, Okrouhlá Radouň, Zadní Chodov and Vítkov II). The sandstone-hosted deposits in northern Bohemia (Hamr, Stráž, Břevniště, Osečná-Kotel and Hvězdov uranium deposits) were found after gamma logging of hydrogeological borehole [30]. In 1989, the decision was made to reduce all uraniumrelated activities. Following this decision, in 1990, expenditures decreased to about 7 million USD and have declined ever since. No field exploration has been carried out since the begin-

Most of the known uranium resources in the Czech part of the Bohemian Massif occurred in 32 ore deposits, of which 30 have been mined out or closed up to year 1993. Of two remaining deposits, the Rožná and Stráž were mined also from 1993 up to 1996 (Stráž) or up to 2017 (Rožná). The mining of the last Central European uranium deposit (Rožná) was stopped in April 2017. The very small recent production of uranium in the Stráž uranium deposit is part of remediation of the after-effects of the in-situ leaching that impacted a total 266 million m3

Germany, the first exploitation of uranium ores started in 1947 and 1948.

exploited.

ning of 1994 [31].
