Bismuth object 31
| Bismuth object 31 | |||
|---|---|---|---|
| General information about the mine | |||
| other names | Factory 75 | ||
| Information about the mining company | |||
| Operating company | Wismut AG / SDAG | ||
| Employees | 1000 | ||
| Start of operation | 1947 | ||
| End of operation | 1961 | ||
| Funded raw materials | |||
| Degradation of | |||
| Geographical location | |||
| Coordinates | 50 ° 34 '41.1 " N , 12 ° 22' 59.5" E | ||
|
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| Location | Lengenfeld | ||
| local community | Lengenfeld | ||
| District ( NUTS3 ) | Vogtland district | ||
| country | Free State of Saxony | ||
| Country | Germany | ||
The object 31 was a Aufbereitungsgsobjekt and as an independent structural unit within the Wismut AG / SDAG reports directly to the head office.
Development of the property
The processing plant of the Pechtelsgrün wolframite mine is hidden under the designation Object 31, also Factory 75 . An operational list dated August 28, 1945 shows that the tungsten concentrate produced in the plant from September 1945 from the ore of the Pechtelsgrün mine was administered by SMA Saxony and delivered to the Soviet Union as a reparation payment .
Processing was placed under Soviet administration as early as November 1946. The background was the hope for a positive result of the exploration work for uranium in the Klingenberg - Tannenbergsthal , Gottesberg and Eibenstock area . However, the investigations were discontinued in January 1947 and the mineralizations found were classified as third-rate. According to a note from operations manager Höpner, the plant started working for field post number 27304 from February 6, 1947. This was the Saxon Mining Administration of the Ministry of the Interior of the USSR , which operated under the field post number of the Red Army . On May 30, 1947, the processing of the plant was transferred to Soviet ownership on the basis of order No. 113 of the SMA Saxony . There was thus a separation between processing and pit. After the Wismut AG branch was entered in the commercial register in Aue on July 2, 1947, the processing plant was named Object 31. The seat of the property was in Pechtelsgrün until January 1950 , then in Lengenfeld . Initially, ores from the Annaberg deposit were processed . Ore mining began here in February 1947. Furthermore, from the summer of 1947 ores from the deposit precipitation . The ore was transported by the Deutsche Reichsbahn to Lengenfeld station and loaded onto a dump truck at an ore loading facility on the Grüner Weg and transported to the Pechtelsgrün shaft. Here it was pre-sorted and shredded and then transported to processing by cable car . The ores were processed here from 1947 to 1958 using radiometric and wet mechanical methods. The chemical processing also ran in parallel. From 1957 onwards, Wismut started processing with ion exchangers for the first time. The number of workers rose from 500 in 1948 to over 1000 after 1950. With the construction of a separate rail connection for processing and bunker systems, it was possible from 1949 to unload ore directly at processing. For this purpose, construction of a connecting railway began in May 1949 under the direction of chief engineer Wlassow. When it was commissioned in May 1950, the connection consisted of two tracks 185 meters and 155 meters long. As early as 1952, the connection was extended by a third track with a length of 210 meters. Another extension to track 4 took place in 1959. With this last extension, operations management also went to SDAG Wismut and six electric cable winches and a wagon tipping system were installed. From July 1, 1961, legal ownership went to VEB Baumechanisierung Zwickau. From 1949 the ores from the Bergen deposit and from 1950 also the ores from the Zobes deposit were processed. In 1951 the ores from the Sorge-Settendorf and Culmitzsch opencast mines were added, and from 1952 the ores from Schmirchau .
With the commissioning of the processing facility in Seelingstädt in 1961, operations were stopped. 3,063,000 tons of ore were processed between 1950 and 1960. No figures are available for the period from 1947 to 1949. Based on the ore-uranium ratio of 1950, around 200,000 - 240,000 t of ore were processed during this time. The share of ores from the Ore Mountains and Vogtland was 65–70%. The share of the Ronneburg ores was 30–35%. The residues from processing were deposited in two heaps and a landfill facility.
Due to extreme rainfall between July 9th and 12th, 1954, which led to a flood of the century, the dam of the sedimentation system broke. As a result, 50,000 m³ of tailings were washed out and largely flushed into the steering pond through which the Plohnbach flows. This pond is a small dam built in 1890. The pond was almost completely filled with the mud masses. The uranium quantity calculated in the tailings of the steering pond is given as 10 to 14 t.
Processing method
Radiometric processing
Only ores from deposits in the Ore Mountains and Vogtland were suitable for radiometric processing. Due to the even distribution of the uranium in the ore, the Thuringian ores could not be processed radiometrically. After the ore had been washed and classified , it was mechanically sorted and measured using detectors ( Geiger counters ). Initially the sorting was done by hand, mostly by women, later using compressed air nozzles. It was sorted into commodity ores> 1% uranium content and factory ores with 0.017 - 1% uranium content. The ores were delivered directly to the Soviet Union. The factory ores were packed in metal canisters and delivered to Zeche 50 in Aue. All incoming ore was collected, sorted, packed and delivered to the Soviet Union here.
Gravitational processing
Thuringian ores could not be processed here either. After the ores had been ground in ball mills, the ore sludge was separated from the deaf material using various setting machines and washing stoves based on the density principle. The ore concentrate was dried on steam-heated plates and driven to the 50 mine in dump trucks.
Chemical processing
A percolation leaching was carried out from 1947 to 1950. Here the ore was leached in containers with dilute sulfuric acid . The resulting uranyl sulphate was mixed with sodium hydroxide solution and yellow cake (ammonium diuranate) was precipitated and obtained by means of chamber filter presses. The concentrate was then dried on steam-heated trays and manually filled into cardboard buckets. In percolation leaching, relatively coarse-grained ores that had to be put into the containers by hand were leached. This process was not very efficient, but it made separating the uranyl sulfate very easy.
From 1950 the process was replaced by agitation leaching. Here diluted sulfuric acid or soda was added to a very finely ground ore in the ore pulp . The rest of the process is similar to percolation leaching, but separating the uranium products from the pulp is much more complicated. But the yield is much higher. When leaching with sulfuric acid, not only uranium but also other heavy metals contained in the ore are dissolved. In contrast, leaching with soda produces a very pure concentrate, since only the uranium is dissolved as a heavy metal. The disadvantage, however, is the lower output. Which of the two leaching methods was used depended on the composition of the ores. The calcitic ores from the opencast mines were leached with soda and the silicate ores from Ronneburg with sulfuric acid.
Treatment with ion exchanger
A fixed bed ion exchanger was used in a countercurrent process. The ore slurry was passed over the ion exchanger and the uranium was deposited on it. The exchanger was then regenerated using sodium chloride solution and soda and the uranium accumulated was dissolved. The uranium contained in the solution was precipitated with binding agents and extracted with filter presses. Here, too, the end product was yellow cake. An ion exchanger with the designation WNS developed by Wismut in Zeche S of Factory 95 in Dresden-Gittersee was used.
Heaps
The residues of the radiometric processing were piled up on the company premises and sold as building material or road gravel.
The residues of the gravitational processing were piled up on the south and north heap. The approximately 550 meter long Südhalde is located between the Plohnbach and the Zwickau-Lengenfeld railway line. It has an area of 3.6 hectares. The north dump is located north of the railway line. Its area is 9.1 hectares.
The residues of the chemical treatment were washed in behind the embankments of the north heap and in a sedimentation plant ( IAA ) in the valley of the open stream. The volume of the tailings from uranium ore processing is 890,000 m³.
Reuse
Probably after 1961 the ores from the wolframite mine were processed. The question of the processing of these ores between 1947 and 1961 has not been clarified. In a study carried out in 2002, increased tungsten and molybdenum contents were found in the steering pond, but also in the reed area below the sedimentation basin. The tailings of the dam breach of 1954 are deposited in these areas. The sedimentation basin itself and the dumps were not examined. The increased tungsten and molybdenum values can be an indication of the processing of these ores during the period in question. After wolframite mining in Pechtelsgrün ceased in 1968, the newly formed VEB Vogtlandgruben Lengenfeld took over the facilities. In 1970 the company was renamed VEB Fluß- und Schwerspatbetrieb Lengenfeld .
In 1985 the west dam broke, but this had only a minor impact on the environment.
Until 1990, the residues of fluorspar processing were flushed away in the sedimentation basin. They reach a thickness between one and eight meters.
In June 1990 VEB was converted into Fluß- und Schwerspat GmbH Lengenfeld . In 1991 the processing operation was stopped. In 1993 the company was integrated into the company for the safekeeping and utilization of closed mining operations mbH (GVV) and closed in 1997.
Redevelopment
Company premises
From 2001 to 2002, GVV GmbH demolished a large part of the buildings as part of the rehabilitation of radioactively contaminated areas. In 2003, the mountain supervision over the company premises was ended. The operating areas are now used by Schachtbau Nordhausen , Reuss GmbH and one of the two rifle clubs in the city of Lengenfeld.
Ore loading on the Green Way
Ore loading points 1 and 2 were in operation from 1947 to 1949. The ores delivered by the Reichsbahn were loaded onto trucks here. Existing uranium ore residues and contamination of the soil between 0.40 and 1.20 meters deep were detectable. As part of the rehabilitation of old Wismut sites project, the areas were rehabilitated in 2003 and the radioactively contaminated excavation was installed in the IAA.
North and South Halde
Both heaps were contoured and covered in the late 1960s. They were then afforested with spruce trees. In the meantime they have been developed as a local recreation area. At the beginning of the 1970s, a 2.8 hectare police training area with a firing range was created in the northern part of the Nordhalde. This is now deserted and the area is covered with birch trees. The investigation of the contamination with uranium and uranium-derived products, carried out in 2004, showed that the radioactive pollution is low apart from a few points and does not require any remediation. The area of the police practice area was classified as in need of renovation due to lack of coverage.
Settling basin
An investigation into the radioactive contamination of the tailings was not carried out in 2004. The sedimentation basin was being renovated at the time. In 1999 GVV GmbH commissioned the development of a renovation concept. After planning in 2001, the redevelopment plan was approved in 2002. The renovation was carried out in 2002–2004. The edge dams were re-contoured and the former dam breach on the West dam was renovated. The sedimentation basin was covered and greened. The renovation was completed in 2005.
Steering pond
2003–2004 a concept for the rehabilitation of the steering pond was developed. The clearing work was carried out in December 2009. The renovation began in April 2010 and was completed in November 2011. The radioactively contaminated excavation was installed on the former police training area and provided with a one-meter-thick cover. On June 23, 2012, the area of the redeveloped Lenkteich pond was opened as a local recreation area with a folk festival.
literature
- Werner Runge et al .: Chronicle of the bismuth . Ed .: Wismut GmbH. Self-published, Chemnitz 1999 (CD).
- Stefan Ritzel: Natural radionuclides in the environment - occurrence, anthropogenic influences and radiological relevance in selected mining areas in Germany pp. 180–206 . Ed .: Leibnitz University of Hanover. Hanover 2008 (dissertation).
- Manja Seidel: sorption of metals and semi-metals on sediments in the mining-influenced wetland Lengenfeld / Vogtland . Ed .: Bergakademie Freiberg. Freiberg 2002 (Geoscience Vol. 8).
- Lengenfeld indicator no. 259/300/301
Web links
Individual evidence
- ↑ Michael Hammer: The Pechtelsgrün Wolframitgrube In: Lengenfelder Anzeiger No. 300 2016, p. 14
- ↑ Wilfried Rettig: From Herlasgrün to Klingenthal, across the Saxon Vogtland. P. 127.
- ↑ Stefan Ritzel: Natural radionuclides in the environment - occurrence, anthropogenic influences and radiological relevance in selected mining areas in Germany In: Dissertation Leibnitz Universität Hannover 2008, p. 199.
- ↑ Werner Runge: Chronicle of Wismut Chemnitz 1999, 2.3.3 p. 8.
- ↑ Manja Seidel: Sorption of metals and semi-metals on sediments in the mining-influenced wetland Lengenfeld / Vogtland. In: Geoscience Vol. 8, 2002, p. 51.
- ↑ Area renovation ore loading point 1 Lengenfeld. In: Wismut Projekte 2003. Retrieved on August 14, 2018 .
- ↑ Area renovation ore loading point 2 Lengenfeld. In: Wismut Projekte 2003. Retrieved on August 14, 2018 .
- ↑ Stefan Ritzel: Natural radionuclides in the environment - occurrence, anthropogenic influences and radiological relevance in selected mining areas in Germany In: Dissertation Leibnitz Universität Hannover 2008, pp. 182/205/206.