Worthlah-Ohlendorf mine
| Worthlah-Ohlendorf mine | |||
|---|---|---|---|
| General information about the mine | |||
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| Mining technology | Expansion fracture construction | ||
| Funding / year | up to 743,000 t | ||
| Funding / total | 9.01 million tons of iron ore | ||
| Information about the mining company | |||
| Operating company | Ore mining Salzgitter AG | ||
| Employees | up to 552 | ||
| Start of operation | 1939 | ||
| End of operation | 1966 | ||
| Funded raw materials | |||
| Degradation of | Iron ore | ||
| Greatest depth | 967.8 | ||
| Geographical location | |||
| Coordinates | 52 ° 4 '44.4 " N , 10 ° 27' 0.5" E | ||
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| Location | Ohlendorf, Flachstöckheim (Worthlah shaft) | ||
| local community | Salzgitter | ||
| Independent city ( NUTS3 ) | Salzgitter | ||
| country | State of Lower Saxony | ||
| Country | Germany | ||
| District | Peine-Salzgitter area | ||
The Worthlah-Ohlendorf mine is a former iron ore mine in the Peine-Salzgitter district. The mine was in the districts of Salzgitter-Flachstöckheim and Salzgitter-Ohlendorf . The ore deposit was discovered between 1920 and 1923 by Anton Raky with test drilling. First excavation work began in 1936, and in late 1939 was the promotion added. The mine was closed on May 1, 1966 due to a lack of sales.
geology
The Flachstöckheimer Sattel is about five kilometers east of the Salzgitter ridge and extends in the north to Flachstöckheim and in the south to Ohlendorf. The saddle is completely leveled, its core is a salt dome, the salt level of which is about 80 meters below the surface.
The iron ore deposit is located on the eastern flank of this Flachstöckheim salt dome and extends from here 5–6 km east to the Oderwald . The deposit, which is up to 1000 m deep, had a steep to overturned dip on the flank of the salt dome , the deposit flattened towards the depth. The Reclining of the deposit was created by Lias - and Dogger formed -Tonen. The iron ore deposit was formed in the Neocom period by deposits near the coast.
Since the process of sedimentation was repeated here several times, the camp consisted of individual sections that were separated by thick layers of clay and had to be dismantled separately. The top part was the red warehouse with a thickness of 9 to 11 meters. The red-brown camp (4–6 m thick), the brown camp (4–9 m thick) and the black camp (2.5–4.5 m thick) followed below . Mostly it was oolothic (Lower Cretaceous) iron ore, the Fe content of which was between 30% and 33%, the silica content was 22-25%. The further results of the chemical analyzes showed 4.1-4.5% CaO, 1.5% MgO, 9.9% Al 2 O 3 , 0.4% P and 0.11% V. The ore was because of its strength and its high salt content of 18 to 19 kg of salt per ton of ore is difficult to process using wet technology.
History until mid-1937
In contrast to most other ore deposits on the Salzgitter ridge, the deposit does not come to light and was therefore discovered relatively late. In 1920 the August-Thyssen-Hütte commissioned the drilling contractor Anton Raky to carry out test bores on the eastern flank of the Flachstöckheim salt dome and in the area of the Oder forest. Based on the positive results of this test drilling several were ore fields to the union Widukind and the August-Thyssen-Hütte awarded . In 1927, the United Steel Works (VESTAG) took over the majority in the Widukind union.
As a result of the shortage of iron ore due to the loss of the Alsace-Lorraine ores, plans arose for the first time this year to use the Salzgitter ores and to build a steel mill near the ore deposits. After the end of the global economic crisis , this project was initially not pursued. Only when, as a result of the first four-year plan adopted by the National Socialist government in 1936, the demand for greater independence became stronger, did VESTAG resume the search for iron ore deposits. In the same year, the sinking work for a shaft began on the site of the former Friedrichroda potash mine near Flachstöckheim . This work had to be stopped at a depth of 104 meters due to strong water inflows.
A new starting point was then chosen 400 m east of the first attempt and a new shaft was sunk here. By the time it was taken over by the Reichswerke Hermann Göring in October 1937, the work had reached a depth of 100 m.
1937 to 1945
planning phase
On July 23, 1937, the ordinance on the merger of mining facilities came into force. In the entire Salzgitter area, the Reichswerke Hermann Göring took over the mining activities of the previous owner on October 1, 1937. After further test bores and speculations in the area of Flachstöckheim, Ohlendorf and Klein-Flöthe in 1938/39, the Reichswerke owned 18 mine fields with a total area of 37.5 million m 2 .
The first plans for the ore mine envisaged expanding it into a large facility with three large day shafts. In addition to the Worthlah shaft, which had already been started, another shaft was to be sunk at Ohlendorf and a third 600 m northeast of Nienrode . The first exploration of the deposit was to take place from the Worthlah shaft. The other two shafts were to be developed as the main hoisting and cable car shaft and Worthlah would then only be used as a weather shaft. The workforce was planned to be 3500 men, who were to produce a daily output of 14,000 tons. The outbreak of the Second World War prevented the implementation of the plans on this scale - the construction of the Nienrode shaft was initially postponed and then abandoned entirely after 1945.
Exposure of the deposit
Worthlah Well
In October 1937, the sinking work on the Worthlah shaft taken over by VESTAG was continued. Since they wanted to start mining ore as soon as possible, no expansion of the shaft diameter was made and the clear diameter of just four meters was left. At a depth of 200 meters, a first level was set to explore the ore deposit and to the west, i. H. to the old Friedrichroda potash mine . The cross-cut was not durchschlägig to Kalisch Eight because it was feared liquor burglaries from salt dome.
At the beginning of 1939 the previous wooden abbey tower had to be replaced by a steel head frame , as the wooden frame was too weak for work at greater depths. After continuing the shaft work, the ore deposit was reached in 1939 at a depth of 675 meters; the planned final depth of 779 meters was reached in December 1939. At 750 meters, the 6th level was set, which later became the main production level. Further levels were exposed at 200, 324, 444, 544 and 633 meters. At the time when the sinking work was completed, after a year and a half of construction, the daytime facilities had also been completed, including loading facilities and a siding for wet processing at Salzgitter-Calbecht . The ore mining could still be started in 1939.
Ohlendorf shaft
In April 1940, the sinking work for the Ohlendorf shaft began. This was about two kilometers south of the Worthlah shaft and east of Ohlendorf in an area in which no ore was available. After only six months, the depth was 740 meters. However, due to the significant influx of salt water in this area, the work had to be temporarily suspended. To reduce the inflow, the shaft wall was cemented in this area, while the rest of the area was lined with bricks. On November 11, 1941, the final depth was reached at 967.8 meters, before the ore deposit had been found at a depth of 885 meters. The 6th to 8th levels were created at 764, 833 and 927 meters. In July 1941, the 6th level with the Worthlah shaft penetrated. The fifth floor was driven in the same year, 1943 then the fourth floor, the sole connections between Worthlah and Ohlendorf were Gegenortverfahren ascended. The 1st to 3rd levels (above 444 meters) were not driven because the mining authority had prohibited this due to the steep and overturned deposit conditions in this area and the proximity to the salt dome.
Operation from 1939 to 1945
After the Worthlah shaft was completed, production began at the end of 1939. At that time, 186 miners had already been created. While only 23,000 tons of ore were mined in 1940, the output had risen to 126,000 tons in 1942 and reached 193,000 tons in 1943 with a workforce of 393 men. In the following two years no increase was possible due to the war.
The excavation between the 5th and 6th levels was carried out near the salt dome for safety reasons with a mountain offset . The camp, steep at 40 degrees and only 2–2.5 m thick, was dismantled to a height of 200 meters, the mountains for the offset were brought in via the 5th level. From 1944 onwards, the more cost-effective widening quarry construction with sweeping cutting was used as a mining method in the Red-Brown Camp located about 1300 m south of Worthlah , this method was then also used in the Red Camp north of the Worthlah shaft above the 6th level.
To accommodate the workers, the Reichswerke began in 1937 to build residential camps throughout the Salzgitter area, which were always close to the workplaces. Camp 29 was built for the Worthlah-Ohlendorf mine from October 1940 to January 1941 . It was near the village of Ohlendorf and consisted of four team and other functional barracks. From the end of 1943 this camp was also used as a prisoner of war camp, mainly for British prisoners of war who were used to work on the mine. The camp was closed shortly after the end of the war.
Shortly before the end of the Second World War, on April 3, 1945, some of the daytime facilities were damaged in a bomb attack on the Ohlendorf mine . A few days later, American troops marched into Salzgitter. The operation of the mine was then stopped.
In operation from 1946
In the spring of 1946, the damaged daily facilities of the Ohlendorf shaft were restored and the mine building swamped , and mine operations were resumed in August 1946. At that time there were 142 miners, this number rose only gradually in the first few years after the end of the war. In 1950, only 255 miners were employed and that year, at 184,000 tons, production had reached roughly the pre-war level. The reason was the stagnating demand, especially for Salzgitter ores, which only rose again when production there was resumed in 1950 after the dismantling work in the Salzgitter iron and steel works. In 1952, for the first time, more than 400,000 tons of raw ore were extracted from the mine, the highest annual extraction rate was reached in 1958 with 743,897 tons. In the previous year there was the highest workforce in the history of the mine with 552 men.
The water inflow to the pit had reached its highest level in 1952 with around 200,000 m 3 - that was about 0.4 m 3 per minute. The problem was the salt content, which was very high at 95–115 g / liter due to the proximity to the salt dome. To dispose of this water, people began in 1950 to drill holes from above ground in a groundwater storey that was already salty due to its proximity to the salt dome. The pit water was then discharged into these so-called swallowing wells , which reached a depth of 60 m. In the course of the operating time, six such wells were built and operated one after the other .
At the end of 1949, construction of the cross-cutting expansion began in Worthlah . At the beginning of the 1950s, the 7th and 8th levels should also be driven. Since the Worthlah shaft with its final depth of 779 meters only reached to the 6th level, a die was sunk about 140 m east of Worthlah from the 6th to the 8th level in 1953/54 ; it was ready for operation on April 26, 1954. From 1956, the straightening sections on the 7th level in 835 m depth and 8th level in 927 m depth were driven from this die - partly in the opposite direction - and in 1958 the excavation reached the 8th underground level .
The Ohlendorf shaft was designed as a large shaft, but expansion was postponed due to the war and the shaft was initially only used as a weather shaft. In 1952 the original plans were resumed and work began on expanding the Ohlendorf shaft into a haulage and cable car shaft. A miners' settlement was built next to the mine site to accommodate the miners. The daytime facilities were expanded to include a siding, ore bunker and loading facilities. In 1960 the main ropeway and ore extraction were relocated to the Ohlendorf shaft. Worthlah shaft was used for rope travel until 1962 and also as a weather shaft.
Shutdown
From autumn 1961, the sales crisis for German iron ore affected sales in the Salzgitter mines. Whereas in 1960 649,000 tons of ore had been mined, two years later the production had to be reduced to 445,000 tons. At the same time, the workforce was reduced from 496 in 1961 to 260 in 1962 within one year. However, the management succeeded in avoiding major layoffs, as most of the miners could be transferred to other mines, especially to Haverlahwiese and Konrad .
As the first of the Salzgitter mines, the Georg mine near grid was shut down in February 1965 . When plans to close Worthlah-Ohlendorf became known in the same year, the workforce gathered on April 28, 1965 for a protest rally. The closure could initially be averted, but funding and workforce were reduced by around a third in the same year. The operation could not be continued for long. On February 1, 1966, the Worthlah mine was shut down and on May 1, 1966, the entire mine was closed with the Ohlendorf mine. After the recovery and excavation work was completed, the pit was abandoned and allowed to sink . The shaft halls and headframes were demolished at the beginning of 1969, and the remaining daytime facilities were taken over by various commercial enterprises.
Since the start of production at Worthlah at the end of 1939, 9.01 million tons of raw ore had been extracted from the mine. Between 1947 and 1965, twelve miners were fatally injured during operation.
literature
- Archive of the city of Salzgitter (ed.): Mining in Salzgitter. The history of mining and the life of miners from the beginning to the present (= contributions to the city's history . Volume 13 ). Salzgitter 1997, ISBN 3-930292-05-X , p. 182–196 (editors: Heinrich Korthöber, Jörg Leuschner, Reinhard Försterling and Sigrid Lux).
- Heinz Kolbe: The history of iron ore mining in Salzgitter: ore area Hannoversche Treue between Salzgitter-Bad and SZ-Engerode / Calbecht . In: Geschichtsverein Salzgitter eV (Ed.): Salzgitter yearbook 1983 . tape 5 . Salzgitter 1983, p. 50-58 .
- Four years of Hermann-Göring-Werke Salzgitter 1938–1941, reprint of the anniversary edition from 1941 . Melchior-Verlag Wolfenbüttel, 2009, ISBN 978-3-941555-06-8 , p. 23-30 and 48-49 .
- Wolfgang Benz (Ed.): Salzgitter - Past and Present of a German City - 1942–1992 . Verlag CH Beck Munich, 1992, ISBN 3-406-35573-0 , p. 574-588 .
- Stadtarchiv Salzgitter (Ed.): Ohlendorf - Forays through history (= contributions to the city's history . Volume 20 ). Braunschweig-Druck GmbH, Braunschweig 2004, p. 259–274 (editors Ursula Wolff, Reinhard Försterling, Ralf Hermann, Jörg Leuschner, and Sigrid Lux).
