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174-511: The Ore Mountains ( German : Erzgebirge ; Czech : Krušné hory ) in southern East Germany at the border with the Czech Republic are closely connected to the history of uranium exploitation. The metal was discovered in a sample from a silver mine in the mountain range, and uranium was produced first as a by-product in the early 19th century and later as a main product from the 1890s on. The chemists Marie and Pierre Curie discovered

348-707: A Hercynian block tilted so as to present a steep scarp face towards Bohemia and a gentle slope on the German side. They were formed during a lengthy process. During the folding of the Variscan orogeny , metamorphism occurred deep underground, forming slate and gneiss . In addition, granite plutons intruded into the metamorphic rocks. By the end of the Palaeozoic era, the mountains had been eroded into gently undulating hills (the Permian massif ), exposing

522-453: A loamy , rapidly weathered gneiss in the east of the mountains producing a light soil. As a result of the subsoils based on granite and rhyolite, the land is mostly covered in forest ; on the gneiss soils it was possible to grow and cultivate flax in earlier centuries and, later, rye , oats and potatoes up to the highlands. Today the land is predominantly used for pasture . But it is not uncommon to see near-natural mountain meadows. To

696-479: A black-shale-type mineralisation. Steinach was also a small black-shale-type deposit, mined in a small open cut producing about 40 tonnes of uranium. The Schleusingen mineralisation was hosted by Triassic sandstones and was mined underground, producing 14 tonnes of uranium. Königstein is situated about 40 km southeast of Dresden in the Elbe Sandstone Mountains . Königstein castle is one of

870-686: A cover up for the Eastern Bloc's highly secretive uranium mining. For the third time in history, thousands of people poured into the Ore Mountains to build a new life. The principal mining areas were located around Johanngeorgenstadt , Schlema and Aue . Uranium ore deposits were also exploited for the Soviet Union in Bohemian Jáchymov (St. Joachimsthal). Its processing was associated with serious health consequences for

1044-850: A drainage adit can provide, they have sometimes been driven for great distances for this purpose. One example is the Milwr tunnel in North Wales, which is about ten miles (16 km) long. Other examples are the Great County Adit in Cornwall, a 40-mile (64 km)-long network of adits that used to drain the whole Gwennap mining area, and the 3.9 miles (6.3 km) Sutro Tunnel at the Comstock Lode in Virginia City , Nevada . A side benefit of driving such extensive adits

1218-614: A few smaller deposits. The deposits are related to deep crustal northwest-trending fault structures, with the most important being the Gera-Jáchymov fault zone containing most of the larger deposits, including Jáchymov on the Czech site of the Ore Mountains, Johanngeorgenstadt, Pöhla-Tellerhäuser, Schneeberg-Schlema-Alberoda in the German part of the Ore Mountains, and Ronneburg black shale-type mineralisation in Thuringia. The size of

1392-496: A height of 807 m above  sea level (NN) on the mountain of Komáří vížka which lies on the Czech side, east of Zinnwald-Georgenfeld , right on the edge of the fault block. Consequently, it is a fault-block mountain range, which has been incised by a whole range of river valleys whose rivers drain southwards into the Ohře and northwards into the Mulde or directly into

1566-504: A height of 922 m above  sea level (NN) , on average only about 140 frost-free days per year are observed. Based on reports of earlier chroniclers, the climate of the upper Ore Mountains in past centuries must have been even harsher than it is today. Historic sources describe hard winters in which cattle froze to death in their stables, and occasionally houses and cellars were snowed in even after snowfalls in April. The population

1740-528: A large number of Bohemian Protestants then fled into the neighbouring Electorate of Saxony . As a result, many Bohemian villages became devastated and desolate, while on the Saxon side new places were founded by these migrants, such as the mining town of Johanngeorgenstadt . Ore mining largely came to a standstill in the 17th century, especially after the Thirty Years' War . Due to the very sharp decline of

1914-488: A leading centre of wood and toy manufacturing. Here, wooden smoking figures , nutcrackers , hand-carved wooden trees ( Spanbäume ), candle arches , ( Schwibbogen ), Christmas pyramids and music boxes are made. Up to the last third of the 20th century, Coal was mined near Zwickau until 1978, around Lugau and Oelsnitz until 1971 and in the Döhlen Basin near Freital until 1989. The mountains that until

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2088-438: A length of 120 km. The eastern Ore Mountains are protected landscape. Other smaller areas on the German and Czech sides are protected as nature reserves and natural monuments. On the ridges there are also several larger raised bogs that are only fed by rainwater. The mountains are popular for hiking and there are winter sports areas at higher elevations. In 2019, the region became a UNESCO World Heritage Site . In English,

2262-454: A literal translation of the German name, and Vyšehory , meaning "high mountains". In Upper Sorbian the mountains are known as the Rudne horiny . The German and Upper Sorbian names, as well as the historical Czech Rudohoří , literally mean "ore mountains". The Ore Mountains are geologically considered to be one of the most heavily researched mountain ranges in the world. The Ore Mountains are

2436-704: A long time, so that for about 100 years the blue colour works had a worldwide monopoly. From about 1820 in Johanngeorgenstadt, uranium was also extracted and was then used to colour glass, amongst other things. Even richer deposits of uranium ore were found in St. Joachimsthal. St. Andrew's White Earth Mine ( Weißerdenzeche St. Andreas ) at Aue supplied kaolin to the Meissen Porcelain Factory in Meissen for nearly 150 years. Its export from

2610-439: A magnetite-skarn mineralisation was discovered and shaft ownership was transferred to an east German iron company for exploration purposes. During exploration in the 1960s, drillings showed radioactive anomalies in areas named Hämmerlein and Tellerhäuser south of Pöhla. It was decided to explore these deposits underground using an adit, which was started in 1967. The portal of the adit was in a valley outside Pöhla. At about 3 km

2784-474: A mine situated on a large flat plain, for instance. Also if the ground is weak, the cost of shoring up a long adit may outweigh its possible advantages. Access to a mine by adit has many advantages over the vertical access shafts used in shaft mining . Less energy is required to transport miners and heavy equipment into and out of the mine. It is also much easier to bring ore or coal out of the mine. Horizontal travel by means of narrow gauge tramway or cable car

2958-546: A result of settlement in the early 12th century at the northern edge of the Ore Mountains, the first silver ore was discovered in the vicinity of present-day Freiberg , resulting in the First Berggeschrey or mining rush. Almost simultaneously, the first tin ore was discovered on the southern edge of the mountains in Bohemia. In the 13th century, colonization of the mountains took place only sporadically along

3132-465: A second trending north–south from Freiberg through Marienberg, Annaberg, Niederschlag, Joachimsthal, and Schlaggenwald. Late Tertiary faulting and volcanism gave rise to basalt and phonolite dikes . Ore veins include iron, copper, tin, tungsten, lead, silver, cobalt, bismuth, uranium, plus iron and manganese oxides. The most important rocks occurring in the Ore Mountains are schist , phyllite and granite with contact metamorphic zones in

3306-412: A significant supplies of tungsten , niobium , rare-earth elements and phosphate in the area, which is being reinvestigated by a private company since 2008. Wismut explored a black shale-type uranium mineralisation below the villages of Hauptmannsgrün and Neumark, Saxony west of Zwickau. It led to 2,500 tonnes of inferred uranium resources being added to the resource base of Wismut, but because of

3480-494: A significant tin mineralisation in skarns as well as magnetite. Some of the magnetite was mined as an additive to concrete for nuclear power plants constructed by the East German government in the 1980s. Small amounts of silver were also extracted, but high arsenic contents of the silver ore made processing very expensive and production of silver was stopped in the late 1980s. An ore shoot with massive native arsenic and silver

3654-653: A veteran commander of GULAG labor camps in the USSR and recipient of the highest Soviet decorations, to lead this enterprise. He was under the direct command of Colonel General Ivan Serov, head of the NKVD/MVD in the Soviet Zone of Occupation and Beria’s deputy. Maltsev applied GULAG discipline methods in the early days of the Wismut operation, such as withdrawing food rations from miners who did not fulfill their quotas or

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3828-660: Is Krušné hory , derived from an old Czech expression krušec , meaning "ore". The mountains are sometimes divided into the Saxon Ore Mountains and Bohemian Ore Mountains. A similarly named range in Slovakia is usually known as the Slovak Ore Mountains . Europe's earliest mining district appears to be located in Erzgebirge, dated to 2500 BC. From there tin was traded north to

4002-478: Is a protected landscape. Further small areas are nature reserves and natural monuments, and are protected by the state. Adit An adit (from Latin aditus , entrance) or stulm is a horizontal or nearly horizontal passage to an underground mine . Miners can use adits for access, drainage, ventilation, and extracting minerals at the lowest convenient level. Adits are also used to explore for mineral veins . Although most strongly associated with mining,

4176-466: Is a small village in the Vogtland mountains. Between 1949 and 1961 the second largest vein-type deposit of the Wismut company was mined there. The geology is very similar to that of Schneeberg-Schlema-Alberoda with similar types of veins and host rocks. But the size is much smaller, the total uranium content is roughly 5,000 tonnes. Unlike most other deposits in the Ore Mountains and Vogtland region, there

4350-512: Is a small village in the western Ore Mountains at the base of the Fichtelberg, the highest mountain in eastern Germany. Mining in the area started centuries ago but mining activity remained minor in the area until after World War II. Wismut started exploration in the 1940s and mined small mineralisations in the area containing a few tonnes of uranium. A shaft was sunk at Pöhla-Globenstein but found only very little uranium mineralisation. However,

4524-571: Is about 15 km south of Ronneburg. It also belonged to Object 90 in Gera. However, it had a totally different geology than the Ronneburg ore field. Culmitzsch is a sedimentary deposit in Permian sandstone, siltstone and limestone. There are two ore horizons containing disseminated pitchblende and coffinite. An interesting feature is pseudomorphosis of uranium minerals after wood. Specimens still show

4698-480: Is also much safer and can move more people and ore than vertical elevators. In the past horses and pit ponies were used. In combination with shafts, adits form an important element in the ventilation of a mine : in simple terms, cool air will enter through an adit, be warmed by the higher temperature underground and will naturally exhaust from vertical shafts, some of which are sunk specifically for this purpose. Most adits are designed to slope slightly upwards from

4872-499: Is called the Crimmitschau fault zone in this particular area. The black shales also contain high amounts of sulfides (marcasite, pyrite) and carbon. Wismut tested several different methods to mine this deposit in the 1950s and 1960s. Some seemed to work, but during the 1950s many fires started in the mines. Sabotage was first considered as the cause, but the increasing number of fires showed that there must be another reason, which

5046-450: Is left. A shaft from the uranium mining era today provides thermal water for heating purposes. The eastern Ore Mountains host only very small uranium mineralisation which produced only 50 tonnes in total. Mining took place at Bärenhecke, Niederpöbel, Johnsbach and Freiberg . The latter was the historically most important deposit of the Ore Mountains, and had produced silver since the 12th century. However, it contributed only very little to

5220-476: Is likely its formation is linked to the vein-style deposits in the Ore Mountains sitting on the same structure, it is a completely different kind of mineralisation. This led to many problems in the first decade of mining. Ronneburg is a small town close to the BAB 4 Autobahn . It is situated about 10 km east of the next major city Gera . Ronneburg hosted a small radon spring, but it was not as famous as those in

5394-450: Is located inside the mountain but above the adjacent valley floor or coastal plain. In cases where the mineral vein outcrops at the surface, the adit may follow the lode or vein until it is worked out, in which case the adit is rarely straight. The use of adits for the extraction of ore is generally called drift mining . Adits can only be driven into a mine where the local topography permits. There will be no opportunity to drive an adit to

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5568-543: Is not responsible for recultivating mining areas which did not belong to the company in 1991 when it was formed out of the SDAG Wismut and there are no funds included in the initial 6.4 billion euro budget for cleaning up those areas. Because most of the smaller deposits in the Ore Mountains and Vogtland were mined out in the 1950s and 1960s and the old mining sites were transferred to the local authorities after mining stopped, there were no plans of Wismut GmbH to recultivate

5742-402: Is seen historically as part of the Ore Mountains, Chemnitz is seen historically as just lying outside them, but Freiberg is included. The supposed limit of the Ore Mountains continues southwest of Dresden towards the Elbe Sandstone Mountains . From this perspective, its main characteristics, i.e., gently sloping plateaus climbing up to the ridgeline incised by V-shaped valleys , continue to

5916-479: Is situated in the westernmost part of the Ore Mountains directly on the border to the Czech Republic and on the boundary between the Vogtland and Ore Mountains. It is famous because in 1789, the chemist M.H. Klaproth discovered the element uranium in a sample from the town's Georg Wagsforth silver mine. About 160 years later, the town became Wismut's Object 01 and the old town center was completely destroyed because of intense near-surface underground mining for uranium. Of

6090-425: Is still used for the most important uranium mineral ore in all veins types, but coffinite deposits also occur. In the oxidation zones of the deposits there is a wide range of secondary uranium minerals. The distribution of uranium minerals in the veins varies considerably with the highest concentration of uranium in places where they crosscut reducing host lithologies like carbon-rich schist and skarn . The width of

6264-793: The Baltic Sea and south to the Mediterranean following the Amber Road trading route, of great importance in the Bronze Age . Tin mining knowledge spread to other European tin mining districts from Erzgebirge and evidence of tin mining begins to appear in Brittany , Devon and Cornwall , and in the Iberian Peninsula around 2000 BC. These deposits saw greater exploitation when they fell under Roman control between

6438-691: The Elbe . The main geologic feature in the Ore Mountains is the Late Paleozoic Eibenstock granite pluton , which is exposed for 25 miles along its northwest–southeast axis and up to 15 miles in width. This pluton is surrounded by progressive zones of contact metamorphism in which Paleozoic slates and phyllites have been changed to spotted hornfels , andalusite hornfels, and quartzites . Two key mineral centres intersect this pluton at Joachimsthal, one trending northwesterly from Schneeberg through Johanngeorgenstadt to Joachimsthal, and

6612-774: The Lusatian Mountains , the Iser Mountains , the Giant Mountains and the Inner-Bohemian Mountains . At the same time it forms a y-shaped mountain chain, along with the Upper Palatine Forest, Bohemian Forest, Fichtel Mountains , Franconian Forest , Thuringian Slate Mountains and Thuringian Forest , that has no unique name but is characterised by a rather homogeneous climate. According to cultural tradition, Zwickau

6786-717: The Western , Central and Eastern Ore Mountains , separated by the valleys of the Schwarzwasser and Zwickauer Mulde and the Flöha (" Flöha Line "), the division of the western section along the River Schwarzwasser is of a more recent date. The Eastern Ore Mountains mainly comprise large, gently climbing plateaux, in contrast with the steeper and higher-lying western and central areas, and are dissected by river valleys that frequently change direction. The crest of

6960-400: The central Ore Mountains is one of the famous historical silver mining towns of the Ore Mountains. Uranium mining by SAG Wismut commenced in 1947 and took place until 1958. About 450 tonnes of uranium were produced. The Niederschlag-Bärenstein deposit is situated in the central Ore Mountains close to the border to the Czech Republic. There was an unsuccessful attempt to open a uranium mine in

7134-420: The discovery of large ore deposits the area was further renamed in the 16th century. Petrus Albinus used the name Erzgebirge ("Ore Mountains") for the first time in 1589, in his chronicle. In the early 17th century, the name Meißener Berge ("Meissen Mountains") was temporarily used. A quarter of a century later the names Erzgebirge in German and Rudohoří in Czech became established. The Czech toponym

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7308-414: The engineering and textile industries . In 1789 the chemical element uranium was discovered in St. Joachimsthal; then in pitchblende from the same area, radium was discovered by Marie Curie in 1898. In the late 1930s, following the discovery of the nuclear fission , uranium ore became of particular interest for military purposes. After the incorporation of Sudetenland into Germany in 1938 all

7482-703: The loess hill country to the north between Zwickau and Chemnitz is referred to as the Ore Mountain Basin ; that from the Eastern Ore Mountains as the Ore Mountain Foreland . Between Freital and Pirna , the area is called the Dresden Ore Mountain Foreland ( Dresdner Erzgebirgsvorland ) or Bannewitz-Possendorf-Burkhardswald Plateau ( Bannewitz-Possendorf-Burkhardswalder Plateau ). Geologically

7656-667: The western Ore Mountains , the Schneeberg-Schlema-Alberoda deposit is situated on the Gera-Jachymov fault zone. This major geological structure with a length of several hundred kilometres strikes NW-SE, running from the central Bohemian Massif in the Czech Republic to central Germany. The main element of this fault zone in the Ore Mountains is the Roter Kamm ('Red Ridge') fault carrying a young quartz-hematite mineralisation, but no uranium. This fault forms

7830-426: The 12th century onwards, and even the forests owned by the nobility could not cover the growing demand for wood. In the 18th century, industries were encouraged to use coal as fuel instead of timber in order to preserve the forests, and this was enforced in the 19th century. In the early 1960s the first signs of forest dieback were seen in the Eastern Ore Mountains near Altenberg and Reitzenhain , after local damage to

8004-477: The 15th century, producing silver, cobalt, nickel and bismuth, and the town of Oberschlema was known for its strongest naturally occurring radioactive waters at the beginning of the 20th century. A radium health center was established in the town in 1914. After the Second World War, Soviet scientists started exploring the old mining areas for uranium, and mining commenced in 1946 even before SAG Wismut

8178-507: The 1930s. Uranium mining by SAG Wismut started in 1947 and ended in 1954, producing about 140 tonnes of uranium. The vein containing most of the mineralisation contains a fluorite-barite mineralisation below the uranium mineralised parts. A private company wanted to start mining this mineralisation in 2010. Marienberg is also an old silver mining town founded in the 16th century in the central Ore Mountains. Wismut mined about 120 tonnes of uranium between 1947 and 1954. A large resource of fluorite

8352-494: The 1950s. Today the former mining area hosts a radon health center reestablished in the 1990s. After a restructure of the company in the 1960s, Object 09 became Bergbaubetrieb Aue (mining division Aue). It developed into the single largest producer of uranium within SAG/SDAG Wismut with a peak production of 4,000 tonnes of uranium in 1965. In the last normal production year, 1989, it produced about 550 tonnes. This deposit

8526-485: The 1970s and studies were made to set up a major tin mine. However, although resources were high and ore grades were better than in the producing tin mines in East Germany at that time, the mineralogy was very complex, preventing the usage of proven milling technologies. Wismut developed a special milling technology for the complex tin ore but it proved to be too expensive and the project was stopped. From Hämmerlein,

8700-664: The 21st century, the working group Naturhaushalt und Gebietscharakter of the Saxon Academy of Sciences ( Sächsische Akademie der Wissenschaften ) in Leipzig merged the Ore Mountains with the major unit group of Vogtland to the west and the major landscape units of Saxon Switzerland , Lusatian Highlands and Zittau Mountains to the east into one overarching unit, the Saxon Highlands and Uplands . In addition, its internal divisions were changed. Former major unit 420

8874-469: The 9th century, were only used in a general sense for the vast forests of the Central Uplands. Frequently the term Miriquidi is used to refer directly to the Ore Mountains, but it only surfaces twice in the 10th and early 11th centuries, and these sources do not permit a clear identification with the ancient forest that formerly covered the whole of the Ore Mountains and its foreland. Following

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9048-472: The Bohemian Way ( antiqua Bohemiae semita ). It was here that Sayda was built, a station on the trade route from Freiberg via Einsiedl , Johnsdorf and Brüx to Prague. In Sayda it joined the so-called salt road that ran from Halle via Oederan and onto Prague. Glass-making was introduced into the region from the second half of the 13th century. The emergence of this branch of trade benefited from

9222-467: The Bohemian mining town of Graupen (Czech Krupka ) its name. With the further settlement of the Ore Mountains in the 15th century, new, rich, ore deposits were eventually discovered around Schneeberg Annaberg and St. Joachimsthal . The Second Berggeschrey started and triggered a massive wave of colonization. In quick succession, new, planned, mining towns were built across the Ore Mountains in

9396-468: The Czech side, is actually the highest town in Central Europe . Only on the relatively inaccessible, less climatically favourable ridges are there still large, contiguous forests, but since the 18th century these have been managed economically. Due to the high demand for timber by the mining and smelting industries, where it was needed for pit props and fuel, large-scale deforestation took place from

9570-739: The Czech–German border, separating the historical regions of Bohemia in the Czech Republic and Saxony in Germany. The highest peaks are the Klínovec in the Czech Republic (German: Keilberg ) at 1,244 metres (4,081 ft) above sea level and the Fichtelberg in Germany at 1,215 metres (3,986 ft). The Ore Mountains have been intensively reshaped by human intervention and a diverse cultural landscape has developed. Mining in particular, with its tips, dams, ditches and sinkholes, directly shaped

9744-716: The Eastern Ore Mountains by narrow fingers of the aforementioned basin. South(east) of the Western Ore Mountains lie the Sokolov Basin , the Eger Graben and the Doupov Mountains . To the north the boundary is less sharply defined because the Ore Mountains, a typical example of a fault-block , descend very gradually. The topographical transition from the Western and Central Ore Mountains to

9918-589: The Eastern Ore Mountains. Here, the artisans were required by Prince-Elector Augustus under the Timber Act of 1560, to buy their wood in Bohemia. Wood from the Saxon Ore Mountains was still needed for the mines and smelters in Freiberg. This export of timber led, among other things, to the construction of an artificial cross-border rafting channel, the Neugrabenflöße , along the river Flöha . Because of

10092-556: The Elbe Valley zone. The western part of the Ore Mountains is home to the two highest peaks of the range: Klínovec , located in the Czech part, with an altitude of 1,244 metres (4,081 ft) and Fichtelberg , the highest mountain of Saxony, Germany, at 1,214 metres (3,983 ft). The Ore Mountains are part of a larger mountain system and adjoin the Fichtel Mountains to the west and the Elbe Sandstone Mountains to

10266-661: The Hämmerlein part of the deposit and is operated by a private society as a visitor's mine. Wisutec GmbH, a daughter company of the Wismut GmbH, holds the exploration license for the Pöhla-Globenstein area at the moment (2013). These two deposits in the Vogtland mountains were operated by Object 06 of SAG/SDAG Wismut. Mining for tin and silver had a long tradition in the area, as did the production of gem-quality topaz . When Wismut started exploration and mining in

10440-423: The Korbußen mine (part of the Beerwalde mining division) and Drosen to the major dump at Beerwalde. To accomplish this task, Wismut GmbH ordered and operated the largest fleet of Caterpillar mine trucks in Europe. After relocation was finished, the dumps were covered. The southern mining area with the refilled Lichtenberg open pit was part of the 2007 federal garden exhibition Gera-Ronneburg. The Culmitzsch deposit

10614-430: The Königstein division of Wismut GmbH. The deposit is connected by a several kilometer long adit to the Elbe River in Dresden. This adit was built in the 19th century to ship coal directly from the underground part of the mines to the river, although it was never used for this purpose. However, the adit had to be refurbished by Wismut GmbH as one of the major tasks at the deposit in order to provide for secure dewatering of

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10788-491: The Ore / ɔːr / Mountains are sometimes referred to as the Ore Mountain Range , but are also sometimes called the Erzgebirge [ˈeːɐ̯tsɡəˌbɪʁɡə] or Erz Mountains / ɛər t s , ɜːr t s / after their German name or the Krušné Mountains / ˈ k r ʊ ʃ n i , - n eɪ / after their Czech name. In Czech they are the Krušné hory [ˈkruʃnɛː ˈhorɪ] , from old Czech krušec , meaning "piece of ore", and were historically known as Rudohoří ,

10962-412: The Ore Mountains reach the city limits of Dresden at the Windberg hill near Freital and the Karsdorf Fault . The V-shaped valleys of the Ore Mountains break through this fault and the shoulder of the Dresden Basin . The Ore Mountains belong to the Bohemian Massif within Europe's Central Uplands, a massif that also includes the Upper Palatine Forest , the Bohemian Forest , the Bavarian Forest ,

11136-428: The Ore Mountains remains unchanged under the title of Southern Ore Mountains ( Süderzgebirge ). The climate of the higher regions of the Ore Mountains is characterised as distinctly harsh. Temperatures are considerably lower all year round than in the lowlands, and the summer is noticeably shorter and cool days are frequent. The average annual temperatures only reach values of 3 to 5 °C. In Oberwiesenthal , at

11310-410: The Ore Mountains was given new life during the First and Second World Wars in order to supply raw materials. Nazi Germany also saw the resumption of silver mining. Afterwards the people returned to the manufacture of wooden products and toys , especially in the Eastern Ore Mountains. The clock industry is centred on Glashütte . In the Western Ore Mountains, economic alternatives were offered by

11484-446: The Ore Mountains. Exploration in the area started in 1949, and the first shafts were sunk in 1950. The deposit was operated by Object 90 with its head office in Gera. During the 1950s exploration work at Ronneburg contributed the most uranium to the resource base of Wismut, showing the significance of the newly discovered deposit. However, there were many difficulties with mining of the deposit because that particular style of mineralisation

11658-492: The SDAG Wismut resource base. In the early years of mining, sorting of ore started in the vein style deposits directly on the stopes. High grade ore containing more than 1% uranium was handpicked and later automatically separated and shipped to the Soviet Union without further processing until 1980. Ore containing less than 1% ( Fabrikerz - factory ore) was sent to mills. In the early years of SAG Wismut, it simply took over existing plants for processing its uranium ores. These were

11832-419: The Schneckenstein mineralisation, which is hosted by metasedimentary rocks, veins at the little Gottesberg deposit are within granites. The small deposit was mined for a few years in the 1950s, producing about 70 tonnes of uranium. The Gottesberg area also hosted tin mines and is today under exploration license by a private German exploration company. Object 08 mined a dozen small deposits around Schwarzenberg in

12006-433: The United States to produce nuclear weapons. On April 4, 1946, the Council of Ministers of the Soviet Union decided to place the uranium mining under the control of the NKVD. Regular mining operation for uranium started in the summer of 1946. Lavrentii Beria , Soviet Minister of Internal Affairs, chief of the NKVD, who was directly responsible for the Soviet atom bomb project, appointed NKVD Major General Mikhail M. Maltsev,

12180-413: The Zobes mines. While the Zobes deposit was in meta-sedimentary rocks, Bergen was an intragranitic deposit. It was recognised worldwide for its excellent and large crystals of secondary uranium minerals like uranocircite . There is also a mineral named after the deposit: bergenite . A part of the Bergen deposit was later mined for granite as construction material in a large open cut. Johanngeorgenstadt

12354-429: The Zwickauer Mulde river. Underground work, especially in Oberschlema, is being carried out to secure near-surface galleries and shafts from collapse and to provide safe airways for radon-containing mine air to prevent it from uncontrolled movement into populated areas of the region. The huge waste rock dumps were either relocated or recontoured and covered with 80 cm of clay and 20 cm of top soil. In 2008, most of

12528-502: The abundance of excess timber, which was created by clearings and new settlements and which was able to meet the high demand of the glassworks. Monks from Waldsassen Abbey brought a knowledge of the glass manufacture to the Ore Mountains. Most glassworks were located in the vicinity of Moldau , Brandau and the Frauenbach valley . The oldest glassworks site is Ulmbach . This timber-hungry industry lost its importance, however, with

12702-420: The adit cut the mineralisation at Hämmerlein. It showed that there was just a minor uranium mineralisation there, which was mined out during exploration phase resulting in a production of 15 tonnes of uranium. However, significant tin mineralisation was discovered in skarns and schists. Further, the skarns also contained zinc , magnetite , indium and cadmium . This mineralisation was intensively explored during

12876-431: The adit does not become blocked. All mine workings below both the drainage adit ("below adit") and the water table will flood unless mechanical means are used for drainage. Until the invention of the steam engine this was the main restriction on deep mining. Adits are useful for deeper mines. Water only needs to be raised to the drainage adit rather than to the surface. Because of the great reduction in ongoing costs that

13050-477: The area there was still active mining for tin. Before Wismut discovered the nearby uranium mineralisations, it had already taken over the processing plant from the tin mine Tannenbergsthal on top of the Schneckenstein mountain in 1948. It investigated the tin mine itself but no uranium mineralisation was found. However, about 2 km from the tin mine the company discovered a uranium mineralisation which

13224-401: The area was recultivated, including flooding the mine, removing the mine buildings and covering the waste rock area. A water treatment plant was set up to remove uranium, radium and arsenic from the mine water. Because of the low water flow from the mine, it was possible to replace the initial active chemical water treatment plant with a passive biological unit (wetland). The adit is still open to

13398-452: The area. Flooding of the mine started in 1991 and in 1997 the water reached the -540 m level as the uppermost level of shaft 371. At this point, the mine was opened for the public as the deepest tourist mine in Europe. A water treatment plant was erected with a final capacity of 1,300 m per hour, removing uranium, radium, arsenic and iron from the contaminated mine water before releasing it into

13572-410: The areas in their original restoration program. However, after negotiations between the state of Saxony, the German federal government and Wismut GmbH contracts were made and funds were provided to restore these old areas, including Johanngeorgenstadt. In this town activities of Wismut GmbH include mainly contouring, relocation and covering of dumps, and securing hazardous underground mining areas. Pöhla

13746-512: The boom in mining, which also enjoyed royal patronage. Mining on the Bohemian side of the mountains probably began in the 14th century. An indication of this is a contract between Boresch of Riesenburg and the Ossegg abbot, Gerwig, in which the division of revenue derived from ore was agreed. Grains of tin ( Zinnkörner or Graupen ) were obtained at that time in the Seiffen mining area and gave

13920-472: The border. From west to east: In the division of Germany into natural regions that was carried out Germany-wide in the 1950s the Ore Mountains formed major unit group 42: Even after the reclassification of natural regions by the Federal Agency for Nature Conservation in 1994 the Ore Mountains, region D16 , remained a major unit group with almost unchanged boundaries. However, at the beginning of

14094-597: The boundary between the Schneeberg and Oberschlema deposits, having a vertical displacement of about 400 m. The second controlling element for the deposit are Variscan granites, which underlie the deposit. The mineralised veins are within the exocontact of the granite, although the oldest uranium mineralisation is about 20 Ma younger than those granites. The third controlling factor is a heavily deformed unit of Ordovician to Silurian meta-sedimentary rocks. This so-called Loessnitz-Zwoenitz-Trough runs east-west, broadening toward

14268-447: The cell structure of the wood but are made of pitchblende. The deposit was mined from 1950 to 1967 in three open pits named Culmitzsch, Trünzig and Sorge-Katzendorf. The average ore grade was 0.06% and total production from the three pits was about 11,000 tonnes of uranium. The deposit extends further north from the mined area. This part of the deposit, called Gera-Süd, was explored underground, but difficult geotechnical conditions prevented

14442-535: The complex nature and small size of the deposit it was decided to not mine it. Another unmined black-shale-type resource is in Rudolstadt in the Thüringer Wald area with inferred resources of 1,300 tonnes. Several small uranium mineralisations were also explored in the Ore Mountains outside the mined deposit areas. Together they account for another 11,200 tonnes of inferred resources, which were added to

14616-726: The crest of the mountains, such as the Freiberg Mines Water Management System or the Reitzenhainer Zeuggraben . Only a few mines remained profitable over a long period. Amongst them was the Himmelsfürst Fundgrube near Erbisdorf , whose 50 continuous years of profitable operation were commemorated in 1818 with the issue of a commemorative coin ( Ausbeutetaler ) and which went on to make a profit continuously until 1848. Thanks to discoveries of rich ore seams it became

14790-409: The decline in industrial production in that period, people without any ties migrated to the interior of Germany or Bohemia. After the discovery of the cobalt blue pigments the mining industry experienced a revival. Cobalt was extracted especially in Schneeberg, and processed in the state paintworks to produce cobalt blue paints and dyes. They succeeded in keeping the method of production secret for

14964-425: The deposit is about 200,000 tonnes of uranium (mined and unmined reserves as well as inferred and speculative resources). After production ceased in 1990 recultivation work began. The mine dumps were the largest task in this mining area. It was decided to relocate most of the dump material of the southern mining divisions (Schmirchau, Reust, Paitzdorf, Lichtenberg) into the open pit Lichtenberg and to relocate those of

15138-552: The dolomite veins, there was no input of new uranium but only remobilisation. These were the most important veins in Schneeberg, not only for uranium but also for Ag and Co-Ni production. Telescoping is also a common feature with different types of mineralisation being found stuck together in the same part of the vein. Beside the uranium-bearing mineralisation types, there are about one dozen different styles of other mineralisation ranging from Sn-W, Pb-Zn, fluorite-barite to quartz-hematite. They had no economic importance but contributed to

15312-517: The early 1950s, when the coal field belonged to the hard coal mining company, two new main shafts in Dresden-Gittersee were sunk to depths of about 700 m and the mine was renamed 'Willi Agatz', after a leader of the East German communist party. In 1968 production of coal for energy production was eventually stopped and the mine was transferred a last time to SDAG Wismut. From that time on coal was only mined for its uranium content. The deposit

15486-422: The early 1990s. In St. Egidien and Aue there were important nickel smelting sites. In Pöhla in the Western Ore Mountains, during exploratory work for SDAG Wismut new, rich lodes of tin ore were discovered in the 1980s. The test workings of that time are now considered the largest tin finds in Europe. Another well-known place of tin production was Seiffen . The village in the Eastern Ore Mountains has become

15660-467: The east. Past the River Elbe , the mountain chain continues as the Lusatian Mountains . While the mountains slope gently away in the northern (German) part, the southern (Czech) slopes are rather steep. The Ore Mountains are oriented in a southwest–northeast direction and are about 150 km long and, on average, about 40 km wide. From a geomorphological perspective the range is divided into

15834-481: The east. This rock unit is formed by quartzites, meta-black shales, amphibolites and skarns. It is contained within phyllites, which form the major rock type in this area of the Ore Mountains. The rocks of the Loessnitz-Zwoenitz-Trough are called the 'productive series', because they carry nearly all of the mineralisation. Although the vein structures can be followed from the productive series into

16008-539: The elements radium and polonium in pitchblende tailings from a Czech uranium mine in these mountains. Radioactive waters were used in several towns for health treatment . The uranium mines in the Erzgebirge, in the south-eastern provinces of Thüringen and Sachsen were the sites of a number of NKVD mining camps employing forced labor. Wismut AG was the Soviet company that ran the uranium mines. Stalin gave greatest priority to this mining project in his competition with

16182-729: The end of 1953 the company was liquidated and the Soviet-East German stock company Wismut (SDAG Wismut) was newly founded, with the Soviet Union and the German Democratic Republic each owning 50%. Working and technological standards improved significantly in the following years. Uranium exploration and mining concentrated in the first years after World War II on the old mining areas of the Ore Mountains and adjacent Vogtland mountains. Many uranium occurrences had long been known there and were accessible using

16356-526: The entrance so that water will flow freely out of the mine. Mines that have adits can be at least partly drained of water by gravity alone or power-assisted gravity. The depth to which a mine can be drained by gravity alone is defined by the deepest open adit which is known as the "drainage adit". The term mine drainage tunnel is also common, at least in the United States. Workings above this level (known as "above adit") will remain unflooded as long as

16530-473: The first exploration targets for uranium and host the largest number of deposits mined by Wismut. All deposits in these mountain ranges are hydrothermal vein-style mineralisations in Palaeozoic metasedimentary and igneous rocks and Variscan age granites. Most deposits are situated in the western Ore Mountains and the neighbouring Vogtland region, whereas the central and eastern Ore Mountains contain only

16704-421: The first type is a primary mineralisation, while the latter two carry remobilised pitchblende from the older vein types. The BiCoNi-Ag-U mineralisation had been mined since the 15th century for its content of silver , bismuth , cobalt and nickel. The heavy black mineral often occurring in these veins was useless to the miners of former times and was named 'Pechblende' (pitchblende) because of its color. This word

16878-645: The forests had become apparent since the 19th century as a result of smelter smoke ( Hüttenrauch ). The German population of the Bohemian part of the Ore Mountains was expelled in 1945 in accordance with to the Beneš decrees . The upper western part of the Ore Mountains, known in German as Erzgebirge , belongs to the Ore Mountains/Vogtland Nature Park . The eastern part, called the Eastern Ore Mountains ( Osterzgebirge ),

17052-415: The government approved a total budget of around 6.4 billion euro, but higher costs are anticipated. This activity includes securing/filling underground cavities, covering dumps and tailings , treating mine water and removal/decontamination of the buildings at the mine and milling sites. In 2011 the restoration program was extended to the year 2022. The Ore Mountains (German: Erzgebirge ) and Vogtland were

17226-589: The hard rocks. In the Tertiary period these mountain remnants came under heavy pressure as a result of plate tectonic processes during which the Alps were formed and the North American and Eurasian plates were separated. As the rock of the Ore Mountains was too brittle to be folded, it shattered into an independent fault block which was uplifted and tilted to the northwest. This can be very clearly seen at

17400-584: The heartland of the Central European mining industry. New ore discoveries attracted more and more people, and the number of residents on the Saxon side of the mountains continued to rise rapidly. Bohemia, in addition to migration from within the country, also received migration from elsewhere, mainly of German miners, who settled in the mountain villages and in the towns at the edge of the mountains. Under Emperor Ferdinand II an unprecedented Re-Catholicization began in Bohemia from 1624 to 1626, whereupon

17574-511: The heavy amounts of snow a natural Dwarf Mountain Pine region is found near Satzung , near the border to Bohemia at just under 900 m above  sea level (NN) . By comparison, in the Alps these pines do not occur until 1,600 to 1,800 m above  sea level (NN) . The term Saltusbohemicus ("Bohemian Forest") for the region emerged in the 12th century. In the German language

17748-474: The hydrogeological situation was difficult because of the high amount of uranium-bearing solution in the sandstone units hosting the mineralisation. Above that unit there are three aquifers supplying water to the cities of Pirna and Dresden. Therefore, large amounts of water had to be treated before the mine could finally be flooded. The uranium extracted in this cleaning process was sold to an American company in solution form. The total production of uranium from

17922-484: The landscape and the habitats of plants and animals in many places. The region was also the setting of the earliest stages of the early modern transformation of mining and metallurgy from a craft to a large-scale industry, a process that preceded and enabled the later Industrial Revolution . The higher altitudes from around 500 m above sea level on the German side belong to the Ore Mountains/Vogtland Nature Park  – the largest of its kind in Germany with

18096-431: The large variety of the several hundred minerals known from the deposit. Especially in the oxidation zones of Schneeberg and Oberschlema, many rare secondary minerals are found, with many of them being newly discovered there. For example, in samples from a single ore shot in Schneeberg five new uranium minerals were discovered in 1871, namely walpurgite , zeunerite , troegerite , uranospinite and uranosphaerite . Zobes

18270-455: The largest vein-style uranium deposit in the world. After the political changes production slowed down in 1990 and eventually stopped on 31 December 1990. Together with the closure of the uranium mine at Pöhla and the tin mines at Altenberg and Ehrenfriedersdorf this ended the 800-year-old history of metal mining in the Ore Mountains. After the end of production, the newly formed Wismut GmbH as successor of SDAG Wismut started restoration of

18444-493: The last normal production year, 1989. Political and economic changes in East Germany and the subsequent reunification of Germany led to the cessation of uranium mining in December 1990. The Federal Republic of Germany assumed ownership of the East German and Soviet stocks of the company and transformed the company into Wismut GmbH in 1991. This new company is responsible for restoring the former mining and milling sites, for which

18618-460: The last was shut down in 1962. Milling was concentrated at two central milling sites situated between Zwickau and Ronneburg. The mill at Crossen (a northern suburb of Zwickau) was erected in 1950 using the site of a former paper mill. It was called Object 101 / Factory 38 (later renamed Aufbereitungsbetrieb 101 - milling division 101) and processed ore from all major Wismut deposits. It produced mechanical as well as chemical concentrates and used for

18792-400: The late 11th (and early 12th century) were covered in dense forests were almost completely transformed into a cultural landscape by the mining industry and by settlement . The population density is high right up into the upper regions of the mountains. For example, Oberwiesenthal , the highest town in Germany, lies in the Ore Mountains, and neighbouring Boží Dar (German: Gottesgab ) on

18966-465: The latter one an alcalic-based technology resulting in yellowcake containing more than 70% uranium. The mill processed a total of 74.7 million tonnes of ore, producing 77,000 tonnes of uranium before it was shut down in 1989. Experimental milling was also carried out to process silver and tin ore from the deposits at Niederschlema-Alberoda and Pöhla. Ore Mountains The Ore Mountains ( German : Erzgebirge , Czech : Krušné hory ) lie along

19140-465: The lowest costs of all Wismut mining divisions. The uranium bearing solution from leaching was transported by rail to the Seelingstädt mill where the final concentrate was produced. Total production of uranium until 1990 was about 18,000 tonnes, with 12,250 tonnes by conventional mining and 5,750 tonnes by unconventional methods. In 1990 production ceased, as in the other mining divisions. However,

19314-418: The main adit was driven further during the 1970s to investigate the mineralisation at Tellerhäuser, which was cut at about 7.5 km adit length. This uranium mineralisation was much larger than at Hämmerlein and two blind shaft were sunk to deeper parts of the deposits. Mining started in 1983 and 1,200 tonnes of uranium were produced until the end of production in 1990. Like Hämmerlein, Tellerhäuser also showed

19488-498: The major attractions in this touristic area. Exploration for uranium started in the early 1960s for sandstone hosted uranium mineralisation similar to the ones discovered further south in the Czech Republic. Finally a major mineralisation was discovered in 1963, hosted by Cretaceous sandstones with disseminated uranium minerals in Rollfront-type ore bodies. However, there are also small veins containing barite and pitchblende and

19662-606: The mill of a tungsten mine in Lengefeld (Vogtland), the mill of the Tannenbergsthal (Vogtland) tin mine, a plant processing cobalt ore to produce colours at Oberschlema, a nickel processing plant at Aue, and some industrial areas at Freital. Further, a new mill was erected at Johanngeorgenstadt. These small mills produced different concentrates: mechanical, wet-mechanical and chemical ( yellowcake ). A total of 18 million tonnes of ore were processed in these smaller mills, and

19836-435: The mine water treatment between 1991 and 2008 can be estimated to be 1,000 t. This mining area covers parts of the cities Dresden (part Gittersee) and Freital . Mining for hard coal in the area is known to date from the 16th century. In 1949 Wismut studied radioactive anomalies in parts of the coal field and took over some mines. Mine ownership alternated several times between Wismut and the local hard coal mining company. In

20010-451: The mineralisations ranges from very small deposits with some hundred kilogrammes of uranium content and a few mineralised veins, up to the giant deposit of Schneeberg-Schlema-Alberoda containing nearly 100,000 tonnes of uranium and about 2,000 mineralised veins. There are three major vein types carrying uranium: uranium-quartz-calcite veins (270 million years old), dolomite-uranium veins (Triassic age) and BiCoNi -Ag-U veins (Tertiary age). Only

20184-432: The mineralised vein on a lower and upper level (vertical distance 30 to 45 m). These were connected by small shafts from the lower to the upper level. Then the vein was mined upward using drilling and blasting. The ore was transported to the lower level and brought to the main shafts by rail cars, while the stope was filled with waste rock, as possible. After a vein was mined out, the entrances were sealed to prevent radon from

20358-657: The miners. In addition a dam burst in 1954 at Lengenfeld at a uranium mining waste lake; 50,000 cubic metres of waste water poured down 4 kilometres into the valley. Until 1991 uranium ore was also mined in Aue- Alberoda and Pöhla . Mining operations in Freiberg that had begun in 1168 finally ceased in 1968 after 800 years. In Altenberg and Ehrenfriedersdorf tin mining continued to 1991. The smelting of these ores took place mainly in Muldenhütten until

20532-453: The mines, but the total Wismut zone of mines as well. having up to 15,000 troops there. These troops were under the command of the NKVD military head of Wismut. There were additional armed military units stationed in the uranium mining districts. Military and NKVD checkpoints were present at all approaches to this zone. The mines were surrounded by wooden fences and watch towers, and access to them

20706-516: The mining area. Furthermore, the dumps had to be covered, including ash dumps from the firing of uranium-bearing coal in former times. Seven coal seams are present in the Permian (Rotliegend) volcano-sedimentary rocks of the Döhlen basin. Three of these seams carry in restricted parts a uranium mineralisation, which was mined by the Wismut. Uranium was introduced into the coal-forming organic material in early stages by surficial waters. The source for

20880-428: The mining industry and because the search for new ore deposits proved fruitless, the population had to resort to other occupations. Agricultural yields were low, however, and also the demand for wood was reduced by the closure of smelteries. Many people were already active at that time in textile production. However, since that was not enough for subsistence, the manufacture of wooden goods and toys developed, especially in

21054-402: The mining industry. Settlement in the Ore Mountains was slow to begin with, especially on the Bohemian side. The harsh climate and short growing seasons hindered the cultivation of agricultural products. Nevertheless, settlements were supported by the aristocratic Hrabischitz family and established mainly at the foot of the mountains and along mountain streams into the deep woods. In 1168, as

21228-545: The mining of this resource. The Culmitzsch and Trünzig open pits were used as tailings management facilities after they were mined out by the Seelingstädt mill, which was established in 1961 near the deposit. In the southern part of Thuringa called the Thuringian Forest , mining of three small uranium deposits was undertaken in the 1950s. The largest deposit was Dittrichshütte and was mined underground with several small shafts producing about 112 tonnes of uranium from

21402-556: The most productive Freiberg mine of the 19th century. But even the excavation of the Rothschönberger Stolln , the largest and most important Saxon drainage adit, which drained the entire Freiberg district, could not stop the decline of mining. Because even before the completion of this technical achievement the German Empire introduced the gold standard in 1871, the price of silver dropped rapidly and led to

21576-743: The mountains themselves forms, in all three regions, a succession of plateaux and individual peaks. To the east it is adjoined by the Elbe Sandstone Mountains and, to the west, by the Elster Mountains and other Saxon parts of the Vogtland . South(east) of the Central and Eastern Ore Mountains lies the North Bohemian Basin and, immediately east of that, the Bohemian Central Uplands which are separated from

21750-456: The names Böhmischer Wald , Beheimer Wald , Behmerwald or Böhmerwald were used, in Czech the name Český les . The last-mentioned names are used today for the mountain range along the Czech Republic's southwestern border ( see: Bohemian Forest ). From earlier research, other names for the Ore Mountains have also appeared in a few older written records. However, the names Hircanus Saltus ( Hercynian Forest) or Fergunna , which appeared in

21924-468: The nature of this deposit is under discussion. Most likely it is a combination of a sedimentary style and hydrothermal mineralisation. Construction of the mine started immediately after the discovery and two main shaft along with several ventilation shafts were sunk to depths up to 300 m. Mining started in 1967 and it developed into one of the main producers of SDAG Wismut in the 1970s, with more than 1,000 tonnes of uranium per year in this decade. The ore mined

22098-405: The north of the Ore Mountains, west of Chemnitz and around Zwickau lies the Ore Mountain Basin which is only really known geologically. Here there are deposits of stone coal where mining has already been abandoned. A similar but smaller basin with abandoned coal deposits, the Döhlen Basin , is located southwest of Dresden on the northern edge of the Ore Mountains. It forms the transition to

22272-474: The northern part of the deposit in 1974 ( Bergbaubetrieb Beerwalde) and 1982 ( Bergbaubetrieb Drosen). The mineralisation dips downward in a northern direction which resulted in deeper mining depths. The shafts of the northernmost mine Drosen reached nearly 900 m. The grade of the ore mined was 0.08% uranium on average with a cut-off of 0.02% uranium. However, restricted zones of high grade mineralisation with more than 1% uranium occurred. An ore treatment plant

22446-535: The old adits and shafts from the silver and base metal mining of former centuries. In 1950 the giant ore deposit of Ronneburg and the medium-sized Culmitzsch deposit (both in eastern Thuringia) were discovered and in 1965 the Königstein deposit in the Elbe Sandstone Mountains . The peak of uranium production by the Wismut company occurred from the mid-1960s to the early 1970s, reaching nearly 7,000 tonnes of uranium per year, after which it declined to 3,500 tonnes in

22620-408: The old stopes from entering areas with active mining. This method was used in all vein type deposits of the Ore Mountains. The total production from Niederschlema-Alberoda was over 72,000 tonnes of uranium. Together with the production from Schneeberg and Oberschlema, production losses and unmined resources, the total uranium content was about 96,000 tonnes of uranium, making Schneeberg-Schlema-Alberoda

22794-467: The old town center, only the church survived this part of town history while all other houses had to be removed because of severe damage. Mining took place from 1946 to 1958 and about 3,500 tonnes of uranium were extracted. The deposit extended over the border into Czechoslovakia . While the Czechoslovakian uranium company carried out own exploration and mining on its site of the deposit, one vein

22968-470: The ore underground, seal the blasted blocks, and press sulphuric acid into them. Heap leaching was also carried out as well as uranium extraction from mine water before it was released into the Elbe River. In 1984 conventional ore production ceased and only unconventional methods were used from that year on. Production sunk to about 450 tonnes uranium per year, but the Königstein mining division produced at

23142-468: The overall ore grade. High grade ore was sent directly to the Soviet Union without further processing, while ore containing less than 1% uranium was shipped to the mill at Crossen near Zwickau. This was done until 1980; afterwards all ore was milled, with the sorting plant raising the average ore grade to 0.4% before it was sent to Crossen for processing. An unsuccessful attempt was also made to produce base metals, silver and selenium as by-products. Shaft 371

23316-411: The phyllites and granites, no significant mineralisation has been observed outside of it. The ore field contains about 1,800 mineralised veins. Uranium-bearing veins run approximately northwest to southeast, parallel to the Roter Kamm fault. The oldest type of mineralisation consists of quartz, calcite, fluorite, pitchblende and minor hematite. The age of this primary mineralisation is about 270 Ma and it

23490-528: The range. The highest elevation on the Saxon side is the 1,215-metre-high Fichtelberg , which was the highest mountain in East Germany . The Ore Mountains contain about thirty summits with a height over 1,000 m above  sea level (NN) , but not all are clearly defined mountains. Most of them occur around the Klínovec and the Fichtelberg. About a third of them are located on the Saxon side of

23664-591: The southern edge of the Dresden Basin . North of the Ore Mountains the landscape gradually transitions into the Saxon Lowland and Saxon Elbeland . Its cultural-geographical transition to Saxon Switzerland in the area of the Müglitz and Gottleuba valleys is not sharply defined. The highest mountain in the Ore Mountains is the Klínovec (German: Keilberg ), at 1,244 metres, in the Bohemian part of

23838-502: The state, however, was prohibited by the Prince-electors under threat of severe punishment or even death. Towards the end of the 19th century, mining slowly declined again. Drainage costs increased, from the mid-19th century, led to a steady decrease in yield, despite sinking of deeper galleries ( Erbstollen ) and the expansion of ditch and tunnel ( Rösche ) systems for supplying the necessary water for overshot wheels from

24012-431: The term adit is sometimes also used in the context of underground excavation for non-mining purposes; for example, to refer to smaller underground passageways excavated for underground metro systems , to provide pedestrian access to stations ( pedestrian adits ), and for access required during construction ( construction adits ). Adits are driven into the side of a hill or mountain, and are often used when an ore body

24186-592: The third century BC and the first century AD. Demand for tin created a large and thriving network amongst Mediterranean cultures of Classical times . By the Medieval period, Iberia's and Germany's deposits lost importance and were largely forgotten while Devon and Cornwall began dominating the European tin market. From the time of the first wave of settlement, the history of the Ore Mountains has been heavily influenced by its economic development, especially that of

24360-466: The underground work was finished and nearly all shafts were sealed. Most dumps are poorly restored. Shaft 382 with a depth of 1,400 m will stay open (although it is flooded) and provide a controlled path for radon-bearing air to escape from the mine. There is still some uranium being won as a consequence of the restoration program; it is being purchased by the USA with long-term contracts. Like most deposits in

24534-418: The unprofitability of the entire Ore Mountain silver mining industry. This situation was not altered even by short-term discoveries of rich deposits in various mines nor the state's purchase of all the Freiberg mines and their incorporation into the state-owned enterprise, Oberdirektion der Königlichen Erzbergwerke , founded in 1886. In 1913, the last silver mines closed and the company was disbanded. Mining in

24708-484: The upper reaches of the mountains. Since a large part of the precipitation falls as snow , in many years a thick and permanent layer of snow remains until April. The ridges of the Ore Mountains are one of the snowiest areas in the German Central Uplands . Foehn winds, and also the so-called Bohemian Wind may occur during certain specific southerly weather conditions. As a result of the climate and

24882-519: The uranium production facilities were commandeered for the development of nuclear weapons. After the American atomic bomb was dropped on Japan in 1945, Soviet experts searched for evidence of the German nuclear energy project to support Soviet atomic bomb development . Shortly thereafter, the processing of uranium ore for the Soviet Union began in the Ore Mountains under the code name SAG Wismut ,

25056-404: The uranium production of SAG Wismut. The deposit, which produced at least 6,000 tonnes of silver, contained just 5 tonnes of mineable uranium. Eastern Thuringia developed in the 1950s into one of the major mining centers of Wismut, hosting the giant ore field of Ronneburg and the medium-sized deposit of Culmitzsch. Although the mineralisation at Ronneburg is hosted by the Gera-Jáchymov fault and it

25230-450: The uranium was most likely local volcanic rock units. At a later stage, some remobilisation took place, producing uranium mineralised veinlets in the host rocks of the coal seams. The average ore grade was 0.11% uranium. The SAG/SDAG Wismut carried out exploration in the whole German Democratic Republic. Several uranium mineralisations were discovered but finally not mined because of the small amount or high costs. The largest unmined resource

25404-547: The use of military tribunals for those workers accused of alleged sabotage. But unlike the GULAG forced labor camps in Siberia, it was difficult to hide the abuses of labor in the Erzgebirge, a fairly densely settled region of East Germany. To maintain secrecy and security, however, in early 1947, the mining districts became closed military zones, banning even the East German government party, SED, from activities there. Wismut, as it

25578-419: The veins ranges from a few centimeters to several meters, with an average ore grade of 0.1% of uranium. Lenses of massive pitchblende occur locally with a width of over 1 m. The most important deposits are described below. This ore field was the largest deposit in the Ore Mountains. It is situated about 20 km south of Zwickau in the western Ore Mountains . Schneeberg was an important mining center since

25752-399: The vicinity of newly discovered ore deposits. Typical examples are the towns of Marienberg , Oberwiesenthal , Gottesgab ( Boží Dar ), Sebastiansberg ( Hora Sv. Šebestiána ) and Platten ( Horní Blatná ). Economically, however, only silver and tin ores were used. From that time, the wealth of Saxony was built on the silver mines of the Ore Mountains. As a metal used for coinage, silver

25926-492: The war at an extraordinary rate, reaching its highest number of employees in autumn 1950 with over 200,000 workers. Wismut AG became the largest enterprise in the Soviet Zone of Occupation. The initial program of compulsory labor was eventually supplanted by volunteer labor, responding to higher wages and better working and living conditions. Wismut health records indicate that at least 20,000 miners died of or suffered from lung disease "induced by exposure to radiation and dust". At

26100-480: The west, basalt as remnants in the Plešivec (Pleßberg), Scheibenberg , Bärenstein , Pöhlberg , Velký Špičák ( Großer Spitzberg or Schmiedeberger Spitzberg ), Jelení hora ( Haßberg ) and Geisingberg as well as gneisses and rhyolite ( Kahleberg ) in the east. The soils consist of rapidly leaching grus . In the western and central areas of the mountains it is formed from weathered granite. Phyllite results in

26274-492: The western Ore Mountains between Aue and Johanngeorgenstadt. The largest deposit is the 'Weißer Hirsch' mine (Shaft 235) in Antonsthal, which produced about 700 tonnes of uranium until 1959. The other deposits yielded between 2 and 230 tonnes of uranium, resulting in a total local production of 1,100 tonnes. The dump material of the 'Weißer Hirsch' mine is currently being recycled as construction material. Annaberg-Buchholz in

26448-602: Was connected to the -540 and -990 m level (the depth is related to the Markus Semmler adit dewatering the upper part of the deposit into the Zwickauer Mulde river). Deeper levels were connected by blind shafts. The deepest level opened in 1988 was the -1800 m level, nearly 2,000 m underground, making the mine the deepest in Europe. The mining method used was the same as in the centuries before, although with more modern equipment: galleries were driven along strike of

26622-471: Was depleted in 1989 after producing about 3,700 tonnes of uranium since 1949 and 40 million tonnes of hard coal since the 16th century. It was the last Saxonian hard coal mine to be shut down. The uranium-bearing coal was milled at small local plants in Freital when Wismut first was active in the area in the 1950s. After 1968 the coal was milled at Crossen. Restoration of the area after 1991 was carried out by

26796-412: Was discovered in the late 1970s and early 1980s north of Leipzig , hosted by carboniferous volcano-sedimentary rock units. This uranium occurrence near Delitzsch consists of several separate mineralisations. An inferred resource of 6,660 tonnes was taken into the resource base of Wismut and studies were made for underground exploration. However, the high costs prevented realisation. Wismut also discovered

26970-590: Was established in 1947. Schneeberg at the southern end of the deposit became Object 03 and Oberschlema Object 02. Subsequently the blind (no mineralisation reaches the surface) northern part of the ore field (Niederschlema-Alberoda) was discovered and mining started there in 1949. Object 09 was established to mine the Niederschlema-Alberoda part of the ore field. Mining in Schneeberg continued until 1954 reusing many shafts from previous silver and cobalt mining. Up to that time, about 200 tonnes of uranium

27144-400: Was extracted from Schneeberg. Oberschlema was mined to depths of over 700 m. Mining ceased in 1960 after producing more than 7,000 tonnes of uranium. A high density of veins near the surface and the 'wild' mining methods of the 1940s and 1950s caused the complete destruction of Oberschlema. Most houses were so badly damaged and the subsurface so unstable that the entire small town was removed in

27318-430: Was formed by remobilisation of uranium already enriched in the black shales by synsedimentary processes. Remobilisation was caused by hydrothermal and supergene processes leading to the further enrichment of uranium. The background uranium content in the black shales is 40 to 60 ppm. Like the major vein-style uranium deposits in the western Ore Mountains, the Ronneburg deposit is located on the Gera-Jachymov fault zone, which

27492-440: Was found in the sulphur and carbon content of the black shales in combination with wrong mining methods. The initial mining methods led to many fractures in the rocks, which allowed oxygen to enter the rock. The resulting oxidation of sulfides produced enough heat to spontaneously start fires in the carbon-rich material. These fires became such a major problem that whole parts of the underground area had to be sealed off and production

27666-548: Was grouped with the western part of major units 421 and 423 to form a new major unit, the Western Ore Mountains ( Westerzgebirge ), the eastern part of major units 421 and 423 became the Central Ore Mountains ( Mittelerzgebirge ) and major units 422 and 424 became the Eastern Ore Mountains ( Osterzgebirge ). The current division therefore looks as follows: The geographic unit of the Southern Slopes of

27840-399: Was heavily impacted. This also led to the decision to mine part of the deposit using an open pit, which seriously affected the Ronneburg area. However, in the 1960s special mining technology was developed involving backfilling of the stopes using drillings from the surface. Since then, underground fires have not been a major problem. In the late 1960s the company was restructured and Object 90

28014-445: Was made in 1990 shortly before the end of uranium mining. Some tons of the material were mined, but no processing was done. The positive results regarding base metals at Hämmerlein and Tellerhäuser led to a reinvestigation of tin, tungsten and further resources at Globenstein and significant mineralisation was discovered in the 1980s. But like Hämmerlein, the complex mineralogy prevented further projects so far. After production ceased,

28188-566: Was mined by Wismut under Czech territory under contract between the East German and Czechoslovak governments. The deposit is situated on the western edge of the Gera-Jachymov fault zone. It is located in the exocontact of the Eibenstock granite underlying the deposit. The granite itself carries only minor U-Bi veins; most mineralisation is contained in veins in micaschist. Major mineralisation styles are quartz-carbonate-pitchblende and quartz-calcite-arsenide-Ag-pitchblende veins. The Wismut GmbH

28362-406: Was mined from 1950 to 1960, producing about 1,000 tonnes of uranium. After uranium resources were depleted the mine was transferred to another mining company that started mining barite on a fault zone parallel to the uranium veins. Tin mining ceased in 1964 and barite mining in 1991. On the other side of the valley further uranium mineralisations were discovered and named Gottesberg. In contrast to

28536-517: Was minted on site in the mountain towns into money. The Joachimsthaler coins, minted in the valley of Joachimsthal , became famous and gave their name to the medieval coin known as the Thaler from which the word " dollar " is derived. After the end of the Hussite Wars , the economy in Bohemia, which had been disrupted by the conflict, recovered. In the 16th century the Ore Mountains became

28710-424: Was no historical mining preceding the activities of Wismut. Because of the smaller size of the deposit and the relative low population mining did not impact the area as it did at other deposits mined by Wismut. Only the dump of shaft 362 is left today, others have been removed as construction material and low grade ore. The small uranium deposit Bergen was mined only few kilometers away and was connected underground to

28884-401: Was only through a guarded gate. There were also NKVD posts at district or town levels at the fourteen Wismut mines. A special NKVD group, commanded by a Major Malygin, was very important in its work at all the pits and plants of Wismut. He had the task of investigating all cases of espionage and diversion and reported directly to General Serov. The uranium industry grew in the early years after

29058-431: Was regularly cut off from the outside world. The upper Ore Mountains was therefore nicknamed Saxon Siberia already in the 18th century. The fault block mountain range that climbs from northwest to southeast, and which enables prolonged rain to fall as orographic rain when weather systems drive in from the west and northwest, gives rise to twice as much precipitation as in the lowlands which exceeds 1,100 mm on

29232-402: Was split up into several mining division: Bergbaubetrieb (mining division) Schmirchau (underground), Bergbaubetrieb Paitzdorf (underground), Bergbaubetrieb Reust (underground) and Bergbaubetrieb Lichtenberg (open pit). Open pit mining ended in 1976 when the pit reached a final depth of 300 m. Exploration for new areas of mineralisation led to the formation of two further mining divisions at

29406-572: Was tested in Schmirchau to increase the grade before shipping to the mills, but this proved not to be effective. Most of the ore was sent without further treatment to the mills at Seelingstädt and Crossen. Small amounts of uranium were also produced by underground in-situ leaching and heap leaching of low grade ore and even waste rock. The mined resources of the ore field were 113,000 tonnes of uranium, of which about 100,000 tonnes were produced (the difference are production losses). The total resource of

29580-459: Was the first of all Wismut deposits to be supplied with large modern mining shafts and powerful ventilation in the mid-1950s . The most important shafts where Shaft 38 (Niederschlema), Shaft 366 (Aue-Alberoda) and Shaft 371 (Hartenstein). The latter went into production in 1959 and was the main shaft of the deposit up to the end of production in 1990. Shaft 371 possessed an automated sorting plant used to separate different classes of ore and to increase

29754-618: Was the most important type in Oberschlema. About 100 Ma later a second uranium mineralisation formed. Veins of this type contain dolomite, calcite, pitchblende, minor sulphides and selenides (especially clausthalite). This mineralisation event did not bring new uranium into the deposit but remobilised uranium from the older mineralisation. These dolomite-uranium veins were the major uranium formation in Niederschlema-Alberoda. A third uranium-bearing vein type contains quartz, calcite, Co- and Ni-arsenides, native bismuth, silver and pitchblende. Like

29928-517: Was transported by a cable way down to the Elbe river valley from where it was transported by rail to the mill at Seelingstädt. Besides conventional mining using drilling, blasting and transport of the ore to the mill, already in 1969 studies were started on unconventional production methods for low grade ore using leaching. The low permeability of the sandstone prevented usual in-situ leaching from drillings. Therefore, different methods were developed to blast

30102-464: Was under the political control of the NKVD, dealt with all important issues between the company and its German employees. The Soviet military employees in Wismut, on the other hand, were under the authority of the Ministry of State Security, Minister Viktor Abakumov, who had frequent conflicts with Serov. The NKVD maintained a strict security system in the Wismut mines. NKVD/MVD troops guarded not only

30276-412: Was unknown to the East German and Soviet mining experts. The mineralisation is hosted by Palaeozoic meta-black shales and Meta-basalts. Uranium mineralisation occurs in irregular shaped bodies of highly variable size and uranium content (in average 70 tonnes of uranium per body). The uranium minerals (mainly pitchblende) occur as impregnations, thin veinlets or in breccia zones in these bodies. The deposit

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