Braunschweig-Lüneburg rock salt works
| Braunschweig-Lüneburg rock salt works | |||
|---|---|---|---|
| General information about the mine | |||
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| other names | Grass life | ||
| Mining technology | Cross- cutting ridge construction | ||
| Funding / year | 1 million t | ||
| Information about the mining company | |||
| Operating company | esco | ||
| Employees | 180 | ||
| Start of operation | 1911 | ||
| Funded raw materials | |||
| Degradation of | Rock salt / until 1922 potash salt | ||
| Mightiness | 65 m | ||
| Greatest depth | 670 m | ||
| Degradation of | until 1922 potash salt | ||
| Mightiness | 30 m | ||
| Raw material content | 10% | ||
| Geographical location | |||
| Coordinates | 52 ° 18 '10 " N , 11 ° 1' 0" E | ||
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| Location | Bahnhofstrasse 15, 38368 Grasleben | ||
| local community | Grass life | ||
| District ( NUTS3 ) | Helmstedt | ||
| country | State of Lower Saxony | ||
| Country | Germany | ||
| District | Magdeburg-Halberstadt potash district | ||
The rock salt plant Braunschweig-Lüneburg is an active rock salt mine with an attached factory for the production of food , thawing and industrial salts (e.g. for refrigerants or for chlor-alkali chemistry) in Grasleben , district of Helmstedt . It is the last of a total of five rock salt mines in the Federal Republic of Germany in Lower Saxony .
Originally the pit was created for the extraction of potash salt . Immediately before and during the Second World War there was an underground army ammunition facility in part of the mine .
geology
The formation of the salt dome in the upper Allertal
The salt dome of the upper Allertal is one of around 200 known deposits of this type in northern Germany. The salt layers from which this emerged formed at the time of the Zechstein around 260 million years ago when sea water evaporated in a shallow basin (→ evaporation ). This process was repeated several times, so that various alternating layers of rock salt, potash salts and anhydrite were created through supersaturation and precipitation processes . The salt layers were later covered by further deposits and are now at a depth of around 3000 m . In a weak zone between two mountain floes, the salts have penetrated the slopes of the red sandstone (→ halokinesis ). The salt in the upper part of the salt dome was dissolved and washed away by the groundwater. Hardly soluble anhydrite and clay remained . These formed the so-called gypsum hat over the actual salt deposit.
Geographical location and extent
The salt dome of the Upper Allertal extends along the Aller glacial valley about 10 km east of Helmstedt in a southeast-northwest direction over a length of about 40 to 50 km from Eilsleben in Saxony-Anhalt to Grasleben in Lower Saxony. The average width is 2 km. The Lappwald forms the western boundary . It is assumed that the Rothenfelde salt dome is the continuation of a Zechstein saddle, to which the salt dome of the upper Allertal also belongs.
mineralogy
The overburden above the salt dome is formed from clay layers from the Pleistocene . The salt level is about 300 meters deep. The salt dome consists mainly of rock salt with anhydrite and potassium salt deposits, which can consist of sylvin , sylvinite , hard salts or carnallite . The salt deposit is tectonically very strongly folded.
History and technology
Revelation story
Towards the end of the 19th century, the drilling activities of what would later become the Burbach trade union revealed that potash deposits could be mined on Prussian territory. With the sinking of the Marie shaft in Beendorf in 1897, mining began to develop the salt dome in the upper Allertal.
In 1895, the Braunschweig state government secured the rights to the exploration and extraction of salt deposits on its territory that had previously been free of mountains . After the Duchy of Braunschweig took part in the Asse union , its own activities in the Allertal ceased. The rights were finally sold to a consortium in 1910 that was managed by the company FC Krüger & Co. from Hanover . The Braunschweig-Lüneburg union was founded on August 27, 1910 and entered in the commercial register on December 21, 1910 . The board of the union included, in addition to the chairman Friedrich Carl Kruger Paul The lots , then director of the Deutsche Bank Walter Buerhaus from Dusseldorf , Paul Narjes from Hannover, Ernst Herwig from Braunschweig , the Swiss Karl Wehrli-Thielen and producer Eugen Maggi from Zurich to . The trade union Braunschweig-Lüneburg initially consisted of 1000 Kuxen , from 1912 of 1500 Kuxen, of which the Brunswick state owned 500.
A total of 29 million m 2 (15 Prussian maximum fields ) in the communities of Mariental , Grasleben, Querenhorst and Helmstedt were available as authorized persons , which were expanded by a further 70 million m 2 in 1912 .
After the Brunswick tax authorities had already drilled one borehole, three more followed through the Brunswick-Lüneburg union. Borehole II opened up two potash deposits between 749 and 752 and between 756 and 770 meters depth. Borehole IV, in a strike direction 1000 meters from the Walbeck shaft , encountered rock salt at 336 meters and potash salt between 520 and 538 meters. Hole V by the International Drilling Company reached 326 meters of rock salt, 419 meters to two meters and 427 to a 30 meter thick potash deposit. The starting point was 2500 meters west of Grasleben.
Braunschweig-Lüneburg I mine (Grasleben)
On the basis of the salt outcrops, the drilling of the first Grasleben shaft began at the site of borehole VI in January 1911 . The work on the 5.5 meter wide shaft was carried out by the Rheinisch-Westfälische Schachtbaugesellschaft mbH in Essen and was subject to difficulties due to water inflows. A water seal was finally ensured with a segment extension extending to a depth of 82 meters and another segment between 161 and 301 meters. In addition, masonry was used as a shaft extension . The shaft was completed in 1916 with a final depth of 600 meters. Above ground, the necessary operating buildings as incurred shaft house with headframe and two independent conveyors, conveyor machine house , boiler house , Chew and workshops, as well as Rohsalzmühle and factories. To dispose of the final liquor, a connection was made to the 60 km long sewage pipeline to the Elbe, which was built together with the Burbach potash works .
Braunschweig-Lüneburg II mine (Heidwinkel I)
Around 2500 meters from the Grasleben shaft in the Heidwinkel district , work began in April 1912 to dig a second shaft, the Heidwinkel I mine . The 670 meter deep and 4.75 meter wide shaft was completed in just 14 months, so that on November 1, 1913, the production of potash salts began at the Heidwinkel plant. Tubbings up to a depth of 92 meters, followed by masonry, served as the shaft extension. The extracted raw salt was first transported by cable car and later by a narrow-gauge railway to the factory at the Braunschweig-Lüneburg I shaft. Since the Braunschweig law did not necessarily stipulate two shafts for a mine, Heidwinkel and Grasleben were initially not connected underground and remained legally independent mines. The Grasleben shaft received a weather separator and for safety reasons there were no more than 80 men underground.
Operation as a potash plant from 1914 to 1922
The Braunschweig-Lüneburg union had great expectations of the potash deposits near Grasleben, so two more potash shafts were started near Nordsteimke . In the scheduled production of the potash plant from 1914 onwards, only salts with a K 2 O content of just 8–9% were produced. This cast into doubt the profitability of the operation, the two additional shafts were no longer sunk. It was thanks to the great interest of the Braunschweig state that the potash mining was not stopped immediately. The operation concentrated more on the Grasleben mine.
The following years were marked by a lack of manpower and materials, problems with the energy supply, as well as fewer sales opportunities, caused by the outbreak of the First World War . This situation hardly improved even after the war ended. In 1920, the dismantling had to be stopped completely because too few products were in demand. In the following year, however, there were no railway wagons to transport the potash away. Since a particularly high-quality, extensive rock salt store with 99% NaCl was opened in 1921, the Braunschweig-Lüneburg union decided to end potash mining in 1922 and to shut down the pits as a potash plant on July 1, 1924. The participation figures in the German Potash Indicator last issued by the Potash Inspection Board amounted to 89% of the average participation of all potash plants for the Braunschweig-Lüneburg I mine and 78% for the Braunschweig-Lüneburg II mine.
Operation as a rock salt works from 1925 until the end of the Second World War
In the years from 1922 to 1925, the potash factory was rebuilt to process rock salt, and parts of the plant that were no longer needed were demolished. When production started in 1925, the Braunschweig-Lüneburg plant received a share of 12.6% in the Deutsches Steinsalzsyndikat GmbH . Because of the high quality of the raw salt, table salt was mainly produced. The treated salt but also for the production of refrigerants , as a de-icing salt, for the tanning of leather , as an adjuvant in the recovery of copper and aluminum and as a chemical raw material for the hydrochloric acid production , for chlorine , plastics or disintegrant sold. A good 2/3 were sold on international markets. One exotic product was a bath salt called Grabasol , which was made from ground carnallite. In 1928, the successor organization of the rock salt syndicate, the German Steinsalzbergwerk GmbH sales association , granted the Braunschweig-Lüneburg mine the highest share of sales at the time of 8.42%.
The main production shaft in Grasleben was still not penetrated by the Heidwinkel facility . With 50 gon incident and 65 meters on average powerful rock salt deposit was in depths 400-490 meters in querschlägigem stoping recovered. To this was added of a wooden Gebrück of up to 12 meters with a rotary electric drill blast holes in the ridges drilled. The loose debris was removed in the excavation chambers with a floor area of 2500 m 2 with scrapers into roller holes . The distance transport was carried out in trolleys on the 490-m- sole .
The table salt intended for filling in packets has already been processed underground in both shafts by grinding and sifting and, depending on the customer's wishes, magnesium oxide or potassium iodide was added. Automatic weighing and packing machines were available above ground, and the folding boxes were produced in-house. The remaining salt was ground in the factory and sieved in different grain sizes depending on the use.
The Salzdetfurth AG acquired over the years the Kuxenmajorität to the union Brunswick-Luneburg and 1935 and previously the country Brunswick shares held.
Muna Heidwinkel 1936 to 1945
The Heidwinkel mine was taken over by the Wehrmacht in 1936 and from then on was no longer available for rock salt extraction. Ammunition produced above ground should be stored in a protected manner in the mine rooms . A second shaft was needed to make the ammunition plant independent of the mine. The Heidwinkel II shaft was sunk from 1937 to 1939 . The later third shaft of the Braunschweig-Lüneburg trade union was given a diameter of four meters and a segmental lining up to a depth of 102 meters. Below that, the shaft tube was lined up to the swamp. The final depth was 662 meters. In 1941 an access system with a steel headframe was set up.
A total of 72 storage chambers were set up on two levels. A production area and a housing estate for the Muna workers and their families were built above ground.
In April 1945 the Muna Heidwinkel was captured by American combat troops and later handed over to the British Army .
Under the National Socialists, the salt mine was used as a depot for archival material, such as sound foils with sound recordings from sessions of the Reichstag of the Weimar Republic.
The Braunschweig-Lüneburg rock salt works from the post-war period until today
After the end of the Second World War, the extraction in the Grasleben mine was started again. In the beginning it was feared that the Walbeck potash works, which had been drowned by Soviet troops, would flood . This concern was justified, since at the beginning of the 20th century several Staßfurt potash pits were destroyed by water inflows from their neighboring pits through the marrow security pillar. Fortunately, this never occurred in Grasleben.
The Heidwinkel I / II mine was returned to the Braunschweig-Lüneburg trade union by the Allied military in 1949 after the ammunition depots had been completely cleared. From 1949 to 1953, carnallite with an average K 2 O content of 10% was mined here for a short time . The demand for the inferior potash quickly subsided, so that the extraction soon stopped and in the following years only table and industrial salt based on rock salt was produced.
Vacant parts of the old potash factory were expanded in 1956 to a new shop , workshops and storage rooms. The production in the same year was around 200,000 tons and 400 men worked on the plant. On July 9, 1957, the Braunschweig-Lüneburg I and II / III pits were penetrated for the first time over a 2500 meter long connecting stretch at the 430 m level. This means that the mine was also combined underground to form a single unit.
On April 17, 1959, a major fire broke out in the salt factory in Grasleben, as a result of which all processing , packaging and loading systems were severely damaged. Although the company had initially thought of ceasing to operate because of the major damage, a provisional salt shipment was started again on May 15, 1959. By the end of 1961 the rock salt factory was rebuilt and extensively modernized. While in the previous processing process the salt ran through vertical production lines in several steps, generating a large amount of unsalable abrasion in the form of salt dust, the machines were now mainly arranged one behind the other in a horizontal plane. This was gentler on the products. The systems were automated and equipped with a dedusting device.
With the merger of the potash division of Wintershall AG and Salzdetfurth AG to form Kali- und Salz AG (K + S) in 1971, the mine was incorporated into the new group .
The Grasleben shaft received a new headframe in the 1980s and was converted from the original double conveyor system to a simple one. This shaft is now the central cableway , conveying and extending weather shaft . Elevation levels are located at depths of 430, 490 and 560 meters. Further levels 570, 590 and 640 meters underground are not directly connected to the shaft as substations . A total of 108 km 2 is available.
The Heidwinkel I / II mine serves as the second exit for the mine. The underground main pit ventilator is located at the Heidwinkel II shaft . In addition to the level shared with the Braunschweig-Lüneburg I shaft at 430 meters, there are two levels at 570 and 645 meters, which originally belonged to the Muna.
Since 2002, the Braunschweig-Lüneburg rock salt works has been part of the European Salt Company (ESCO), which is now a 100% subsidiary of K + S.
Current condition (2012)
Braunschweig-Lüneburg mine I
The daytime facilities of the Braunschweig-Lüneburg I mine are located immediately to the east on Bahnhofstrasse in Grasleben. Two construction lines run north-south and are divided in the middle by the works station. In the far east there are two large warehouses for road salt at right angles to the other buildings.
The administration building is located in the far north of the western building line directly on the street, followed by the factory entrance with the gatehouse. The actual mine building with the hoisting machine house, the shaft hall and the headframe are located south of the entrance area. This is followed by the factory for the different types of salt.
The second line of construction east of the railroad tracks used to be the chlorinated potassium factory and now houses storage sheds, road salt factory and various workshops and ancillary facilities. The original colony of the miners is located north of the mine site on the salt road .
In the summer of 2012, the underground laboratory for dosimetry and radiological spectrometry (UDO2) of the Physikalisch-Technische Bundesanstalt was set up in the Braunschweig-Lüneburg rock salt works. After the closure of the Asse mine , which jeopardized the future of the UDO1 underground laboratory there, a replacement was created so that, among other things, measurements of the smallest activities with the help of germanium spectrometers can be carried out with low background radiation. Furthermore, the new laboratory is used for comparative measurements in a European context for self-effect measurement, energy dependence and linearity of local dose rate probes . In the laboratory, collimated radiation fields can be generated, with the help of which the probes can be calibrated in known radiation fields.
Braunschweig-Lüneburg mine II / III
The Braunschweig-Lüneburg II / III mine on the Heidwinkel road essentially consists of the respective hoisting machine houses and the headframes, as well as a shaft hall on the Heidwinkel I shaft. The shafts are about 500 meters apart in a northwest-southeast direction. The Klönne frame strut headframe at the Heidwinkel I shaft from 1913 is one of the oldest preserved in the field of potash and rock salt mining. To the southwest of this there is a spoil dump . Heidwinkel II shaft has an emergency access facility.
Several production and storage buildings have been preserved from the former production area of the Heidwinkel ammunition plant, some of which are now used commercially and some are empty.
literature
- Dietrich Fulda: Kali: The colorful, bitter salt . VEB German publishing house for basic industry, Leipzig 1990, p. 78 .
- Dietrich Hoffmann: Eleven decades of German potash mining . Verlag Glückauf GmbH, Essen 1972, p. 60, 74-75, 104, 120 .
- Rainer Slotta : Technical monuments in the Federal Republic of Germany - Volume 3: The potash and rock salt industry . German Mining Museum, Bochum 1980, p. 225, 261-273 .
Individual evidence
- ↑ Germany's Potash Industry No. 24, 1906 . Free supplement to "Industrie", daily newspaper for coal, potash and ore mining from Wednesday, August 15, 1906, p. 163
- ↑ The Broadcasting Corporation outsource decided early 1940s, particularly relevant archive footage from Berlin and lead them to safety. The British found the sound foils at the end of the war in 1945, brought them to London, where they were recorded on tapes by the BBC and sent to the German Broadcasting Archive in Frankfurt. The material can be heard on SWR2 archive radio.
- ↑ EURADOS: Calibrations of ODL probes at low local dose rates ( Memento from January 10, 2005 in the web archive archive.today ) . Physikalisch-Technische Bundesanstalt, 2006.
