Friedrichroda potash plant
| Friedrichroda potash plant | |||
|---|---|---|---|
| General information about the mine | |||
| other names | Harzer Bergbaugesellschaft Saalburg | ||
| Rare minerals | Hard salt , carnallite | ||
| Information about the mining company | |||
| Operating company | Mining company Friedrichroda (Gumpel Group) | ||
| Employees | to 258 | ||
| Start of operation | August 1919 | ||
| End of operation | 1924 | ||
| Funded raw materials | |||
| Degradation of | Potash salt | ||
| Mightiness | up to 20 m | ||
| Greatest depth | 968 m | ||
| Geographical location | |||
| Coordinates | 52 ° 4 '39.3 " N , 10 ° 26' 33.3" E | ||
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| Location | Neue Str. 75, 38259 Salzgitter (Flachstöckheim) | ||
| local community | Salzgitter | ||
| Independent city ( NUTS3 ) | Salzgitter | ||
| country | State of Lower Saxony | ||
| Country | Germany | ||
| District | Peine-Salzgitter district; Northern Hanover Potash District | ||
The potash mine Friedrichroda is a former mining company in the districts of Salzgitter-Flachstöckheim and Salzgitter-Ohlendorf . Potash salts were searched for for the first time here in 1905, and a shaft was sunk in 1909 . Potash mining began in 1919. In 1924 the operation of the mine was stopped.
geology
The Flachstöckheim salt dome is located northeast of Salzgitter-Bad . This has an elongated-oval shape, extends in north-south direction for a length of 4.5 km and is about 1.5 km wide. The salt dome consists of different Zechstein salt layers that were formed at the end of the Permian period about 260 million years ago through the evaporation of seawater. The approximately 20 m thick Kalisalzflöz Staßfurt consists footwall from hard salt , in the hanging wall of carnallite . As a result of the multiple folding, the salt layers have complex structures - near the Friedrichroda shaft, the potash salt seam is up to 20 meters thick.
prehistory
As early as the second half of the 19th century, after the discovery of the rock salt deposit near Staßfurt and the construction of the potash plant there between 1856 and 1861, research into potash salts also began in the area of today's Salzgitter. In the vicinity of Salzgitter-Thiede, salt deposits had long been known and as early as the 18th century gypsum was being mined on the edge of Salzgitter-Thiede, in the Röverschen gypsum quarry . The Thiederhall potash works had already been sunk here between 1885 and 1891 and a potassium chloride factory was built to process the mined salt . Another potash plant had previously been built between 1884 and 1886 in nearby Vienenburg .
Plänerkalk smears south of Flachstöckheim suspect could be that there is a salt dome and mineable potassium salts could be found. In spring 1905, the potash entrepreneurs Hermann and Max Gumpel founded the Friedrichroda union in Hanover . The rightful of this union included five mining fields in the districts of Flachstöckheim and Ohlendorf, which had previously been bought by the Saalfeld union .
Between 1907 and 1911, the Friedrichroda union had a total of 11 test wells drilled to explore the potash deposits. These confirmed the assumptions and considerable minable potash deposits were detected. During the second drilling on July 31, 1907, the beginning of the rock salt was found at a depth of 126 meters . The first traces of potash were found at 275 meters, and on November 9, 1907, at a depth of 380 meters, a potash deposit with a thickness of over 18 meters with a high potassium chloride content was found. Another potash store was between 521 and 604 meters. The fourth borehole in April 1910 had reached a total depth of 910 meters; a total of 13 bearings were found below 350 meters with a potassium chloride content of up to 20.3%.
Shaft and plant construction 1909 to 1914
In view of the good results of the test drilling, the Friedrichroda union decided to set up a potash plant. In the autumn of 1909, the preparatory work for the shaft construction began. The sinking work up to the point of entry into the salt dome was entrusted to Tiefbau und Kälteindustrie AG (formerly Gebhardt & König, Nordhausen). The pilot hole for the potash shaft was sunk in 1909/10 in the Worthlah Forest on the southern outskirts of Flachstöckheim down to 968 m.
For the sinking work, the decision was made to use the newly developed freezing process , as considerable water inflows were expected during the work in the gypsum hat of the salt dome. On February 7, 1911, work began on drilling the freeze holes in order to prevent water inflows during the construction of the shaft by freezing the shaft walls. After a depth of 40 m had been reached on December 7, 1911, the work was increasingly hampered by repeated caustic inflows and intrusions. In order to continue the devil work, in March 1912 they switched from freezing to deep-freezing. Nevertheless, at a depth of 104 m there was another lye ingress. The cause was probably that the refrigeration machines were switched off too early. After this was put back into operation, it was then possible to sink to a depth of 152.6 m and then place the tubbing column , which was later extended to 185 m.
The final depth of 615 m of the 5.5 m wide shaft was reached in spring 1914. From a depth of 400 m, five levels were set at a distance of 50 m , and there was one extraction level each at 500 m and 600 m. Furthermore, a blind shaft was sunk 300 meters north of the shaft between the 450 m and 500 m level, and a second blind shaft 50 meters further west between the 500 m and 600 m level.
The mountain police requirements required that the pit had to be equipped with a second shaft for ventilation and as an escape route. Therefore, the sinking of the Friedrichroda 2 shaft began in the early summer of 1914 . However, shortly after the beginning of the First World War, the work was stopped at a depth of only 10 m and was not resumed after the end of the war.
In parallel to the sinking work, the necessary daytime facilities such as the boiler and hoisting machine house, the colliery house, a wooden headframe and an administration building were built. The mine was connected to the Klein Mahner train station by a connecting railway . This work was also completed by August 1914.
Operation from 1919 to 1924
Because of the outbreak of war, the Gumpel Group decided not to commission the Friedrichroda potash plant for the time being, but only to carry out maintenance work. It was not until August 1919 that the mining company Friedrichroda mbH , founded after the end of the war, started mining . The plant was of great importance for the Gumpel Group because the potash salts extracted here could be further processed in the company's own potassium chlorine factory in the Asse mine .
The potash plant developed into an economically successful company, and because of the good sales, plans were made in 1919 to build their own potassium chlorine factory. In 1920 the wooden headframe was a steel winding tower replaced and northwest of the well was carried out an extensive tunneling . Further expansion plans were no longer implemented due to the incipient sales crisis in the German potash industry.
The workforce had increased from 144 in 1919 to 235 in 1921. From 1922, the number of employees was greatly reduced against the background of the crisis in the potash industry and in 1924 only 90 men were employed. In the crisis, only a further expansion with a second shaft and a processing factory would have ensured the survival of the potash plant. However, since the Gumpel Group had other plants with the necessary equipment, such extensive investments in the Friedrichroda plant would not have been economical and Friedrichroda was shut down in 1924. Most of the remaining 90 miners and factory workers were transferred to other plants in the group. During the period of operation, a total of 121,150 m 3 of cavities were excavated and three miners lost their lives in the pit.
Further development
The Friedrichroda potash plant was taken over by the Burbach Group in 1928 , which subsequently dissolved the plant on December 12, 1928. The two hoisting machines had already been sold in 1924, most of the other daytime facilities (hoisting machine houses, workshop and administration buildings) were retained.
In 1937 the United Steel Works (VESTAG) showed interest in the shaft system. Extensive iron ore deposits had been identified east of the Flachstöckheim salt dome, for which the VESTAG mining company was planning to mine. Before the negotiations were over, however, the newly founded Reichswerke Hermann Göring took over the lease fields of the Burbach Group in October 1937 . Since the Reichswerke wanted to build their own pits ( iron ore mines Worthlah and Ohlendorf ), the plans of VESTAG were not implemented. By mid-1939, the daytime facilities that were no longer needed were discarded and the headframe torn down. The first to the sole boozed off shaft was not until 1958 filled . The existing daytime systems were taken over by a machine factory and extensively restored in the 1950s. Today the area is used by various industrial companies.
literature
- Heinrich Korthöber, Jörg Leuschner, Reinhard Försterling and Sigrid Lux: Mining in Salzgitter. The history of mining and the life of miners from the beginning to the present . Ed .: Archive of the City of Salzgitter (= contributions to the city's history . Volume 13 ). Salzgitter 1997, ISBN 3-930292-05-X , p. 33-36 .
- Rainer Slotta : Technical monuments in the Federal Republic of Germany . tape 3 : The potash and rock salt industry. German Mining Museum, Bochum 1980, ISBN 3-921533-16-3 , p. 473-479 .
- Heinz Kolbe: The history of iron ore mining in Salzgitter: Flachstöckheim iron ore mine with the Worthlah and Ohlendorf shafts . In: Geschichtsverein Salzgitter eV (Ed.): Salzgitter yearbook 1983 . tape 5 . Salzgitter 1983, p. 50-58 .
- Ernst-Rüdiger Look: Geology, Mining and Prehistory in the Braunschweiger Land (= Geological Yearbook . Volume 88 ). Hanover 1985, p. 277-279 .
- Wolfgang Benz (Ed.): Salzgitter - Past and Present of a German City - 1942–1992 . Verlag CH Beck Munich, 1992, ISBN 3-406-35573-0 , p. 565-573 .
- City of Salzgitter - Department for Public Relations (Ed.): Flachstöckheim - Development of a Village in Eight Centuries (= Salzgitter Forum . Volume 16 ). Salzgitter 1988, p. 67-69 .
- Jörg Leuschner: Village southeast: Beinum, Ohlendorf, Flachstöckheim, Lobmachtersen and Barum in old pictures . Ed .: Stadtarchiv Salzgitter. tape 9 of the contributions to the city's history. Salzgitter 1992, p. 160-163 .
- Thomas Reuter: The shafts of potash mining in Germany . In: Stadtverwaltung Sondershausen (ed.): SONDERSHÄUSER HEFTE on the history of the potash industry . No. 13 . City administration Sondershausen, Department of Culture, Sondershausen 2009, ISBN 978-3-9811062-3-7 , p. 209 .
