Werra potash district
The Werra potash district is a mining district in East Hesse and West Thuringia where potash salts are extracted underground . It is named after the Werra river , which flows through the region.
geology
The Werra potash district opens up the potash seams of the Werra series ( Zechstein 1, Perm) below the plate dolomite , a preferably flat dolomite of the upper Zechstein, which in this area, the northern Rhön , is normally between 200 and 400 meters thick. A total of three rock salt deposits ("lower", "middle" and "upper" Werra rock salt) and two potash deposits were created in the Werra series. The different salts come in different colors depending on the mineral admixture.
The rock salt layers that predominate in quantity in the two potash seams consist almost entirely of the mineral halite . Depending on the composition and the proportion of usable potassium and magnesium minerals , a distinction is made between three rocks from which the potassium seams are built: sylvinite , hard salt and carnallitite . In addition to the salts, other rocks were formed in later Zechstein episodes, some of which are of great importance because they protect the salt deposits, water-blocking clay layers such as. B. the brown-red salt clay and the lower Latvians ("Staßfurt clay"). The brown-red salt clay is approx. 10 m thick and spread over the entire Werra-Fulda area. Individual thin layers of anhydrite, plaster of paris and salt are embedded in the clay stone. Another clastic sediment formed was the Staßfurt clay, known as lower Letten in mining, with a thickness of 15 to 35 m. On the other hand, there is the plate dolomite deposited in Zechstein III (Leine -sequence), heavily bearing groundwater, with an average thickness of 5 to 40 m. The dolomites are harder and denser than limestones and are formed by the deposition of calcite in limestone during the solidification of loose rock by pressure . The water resources in the plate dolomite are naturally salty, which caused major problems when the first potash shafts were sunk. In addition, the plate dolomite is characterized by a large pore volume, which the potash industry uses to sink liquid saline waste water.
The comparatively frequent carbon dioxide inclusions in this region , which when released during the course of mining repeatedly led to sudden, explosive carbon dioxide outbreaks, are attributed to the volcanic origin of the Werra potash district.
history
Beginnings
After potash deposits were successfully explored from the 1880s near Bleicherode in the southern Harz , the successful geological exploration of the region southwest of the Thuringian Forest on the Werra and Ulster in the area between Bad Salzungen and Vacha began after 1890 . In 1893, the proof of the potash salts in the Werra Valley was achieved by unearthing a four-meter-long drill core in the Kaiseroda salt mine on October 5, 1893 . In the Heringen (Werra) area , Wintershall, founded on February 13, 1894 in Bochum , was drilling for the raw material. The first Salzungen shaft was completed in 1899 in Leimbach immediately west of Bad Salzungen, but did not go into operation because of strong carbon dioxide emissions and was finally shut down in 1901. A stock corporation for the promotion of carbon dioxide was established at the location. The Kaiseroda I mine west of Leimbach was the first potash plant in the Werra potash district to go into operation in 1901 .
On April 23, 1900, the groundbreaking ceremony for sinking the Grimberg shaft (named after the Wintershall founder Heinrich Grimberg ) took place near Widdershausen . The plate dolomite was reached in the shaft on December 9, 1901, and on February 12, 1902, it was drilled for the first time by hand, with large water ingresses having to be managed. In September 1902, the upper potash deposit was found at a depth of 424 meters and the final depth of the shaft was finally reached in December 1902. For herring , the work was Wintershall built to process the subsidized potash, on June 1, 1907 followed the groundbreaking for the bore of the shaft herring .
In 1905, the Grand Duke of Saxony potash union was founded, which carried out initial explorations at Dorndorf and Dietlas and finally sank shafts at Dietlas and the Menzengraben five kilometers away . On the western outskirts of Dorndorf, a potash sulfate factory was built and a workers' settlement ("The Colony") was built.
The union Heiligenroda teufte in the mining field between Frauensee , Dönges , Kieselbachplatz , Oberzella and Vitzeroda 1909 three shafts in the corridor of jumping (shaft I to III) and two shafts in Möller base . The union built a second potassium sulfate and chlorinated potassium factory in Dorndorf, which went into operation in 1913.
From 1895 to 1913 a total of 28 potash shafts were sunk in the Werra Valley, seven of which were on the Prussian side and 21 on the Thuringian side. Some holes, e.g. B. at Dankmarshausen and Buttlar remained unsuccessful due to geological problems, especially with water ingress when digging the dolomite plate and did not go into operation. The potash shafts sunk by the Heiligenmühle and Mariengart potash unions in Niederoechsen in 1909 also came to a standstill due to water ingress in 1914. In 1914, 15 shafts in the Thuringian part of the Werra potash district were operational as extraction or weather shafts.
In 1914, mining began in the Abteroda shaft of the Alexandershall union near Dippach , which was discontinued in 1922; the shaft subsequently served as a weather shaft .
In 1925, as part of the expansion of the Kaiseroda trade union near Merkers, the Merkers potash plant was put into operation as the largest potash plant in the world at that time, which produced the salts extracted from the Kaiseroda I (sunk from 1895), II and III (both sunk from 1911) pits processed.
Due to technical problems, the potash mining in Dietlas had to be stopped in 1926, so the older potash plant near Dorndorf was also shut down, and the salt from the Menzengraben mine was transported to the plant of the Heiligenroda union in Dorndorf.
Second World War and the division of Germany
In World War II, potash production was partially disrupted. Some of the pits were used for purposes other than those for which they were intended, for example, large holdings of money and gold from the Reichsbank as well as works of art (including the bust of Nefertiti ) were stored in Merker's shaft and were discovered by American troops on April 8, 1945. The disused Abteroda mine of the former Alexandershall union was expanded into an underground ammunition depot from 1937 and used by BMW for the production of aircraft engines from 1944 . After the end of the war, the Thuringian part of the Werra district was in the Soviet , the Hessian part in the American occupation zone .
Wintershall / K + S in East Hesse
After the Second World War, the Hessian companies remained the property of Wintershall AG , which was taken over by the BASF Group in 1969 . The potash mining of Wintershall AG was brought into the Kali und Salz GmbH (from 1972: Kali und Salz AG) with seat in Kassel . Since then, Wintershall AG's work has concentrated on the areas of crude oil and natural gas.
The remaining Wintershall plants in Heringen and Hattorf in Philippsthal were now located directly on the inner-German border , which at times made it difficult to transport the extracted raw material.
State-owned company in West Thuringia
The potash works located in Thuringia were initially transferred to Soviet ownership as the Sowjetische Aktiengesellschaft (SAG) Kali in 1946 and their previous owners were expropriated. In 1952, the SAG Kali potash works were returned to the GDR and, together with the works of the Association of People's Own Enterprises (VVB) Potash and Salts Halle (Saale) , were handed over to the head office of potash and non-ore mining , from 1956 based in Erfurt . In 1958 the VVB Kali in Erfurt emerged, in 1959 the VEB Kalikombinat Werra . Potash developed into an important export good in the "non-socialist economic area" and was therefore of great importance for the economic system of the GDR . In 1970 the potash operations of the GDR were combined in the Kali combine, which also included VEB Bergwerksmaschinen Dietlas , which was located on the former mine site in Dietlas and supplied mines in Germany and abroad with mining machines. The higher-level combine structures largely served a planned economy coordination in questions of the entire branch of industry and with regard to exports, otherwise the plants were largely managed independently.
Potash production in the GDR has been steadily increasing and the potash works in the Thuringian Werra district have been expanded and modernized for this purpose. From 1955 to 1964, the only new potash shaft in Thuringia was sunk near the Sünna district of Mühlwärts (today shaft II of the Unterbreizbach works ). Due to the gradual decline in sylvinite and hard salt stocks, carnallitite was increasingly mined and processed in the Werra potash district . The GDR's potash production in the Werra and Südharz districts reached 3.5 million tons in 1985, the third largest production volume in the world after Canada and the Soviet Union .
present
After the political change in the GDR and the reunification of Germany in 1990, eight of the nine Thuringian potash plants in the southern Harz and Werra districts were closed by 1993. The reason was the collapse of the sales markets in Eastern Europe and the failure to adapt to market conditions quickly enough. The potash works in Merkers and Dorndorf were also affected . While the Dorndorf plant was closed in 1991 and then completely demolished, the Merkers mine was set up from 1993 onwards , and has developed into a nationally known attraction. Only the Unterbreizbach mine still exists in close association with the neighboring mines in Hesse, after it was transferred from the assets of the Treuhandanstalt to K + S AG . At the Unterbreizbach site , potash salt is still extracted and processed at Shaft I in Unterbreizbach. Shaft II near Mühlwärts is used as a material and cableway shaft.
Today (as of the end of 2015), under the name K + S KALI GmbH - Werra plant, the Unterbreizbach, Wintershall and Hattorf plants are in operation with extraction in the Unterbreizbach I and Hattorf and Grimberg shafts . The Unterbreizbach II, Hera, Herfa and Menzengraben shafts are used as material and ropeway shafts. Other earlier extraction shafts are kept exclusively as weather shafts.
The potash deposits are expected to extend into the 2060s. However, the breakdown causes considerable damage.
Accidents
Mining accidents
Due to the geological structure, there were repeated explosive releases of carbon dioxide in the shafts of the Werra potash district . A carbon dioxide outbreak in the Merkers mine in 1938 claimed 11 lives. Three and six people died in two gas eruptions in the Menzengraben shaft in 1953 and 1958, and three miners died in a carbon dioxide outbreak in the Unterbreizbach mine in autumn 2013.
Tremors
Earthquake in Widdershausen 1953
On February 22nd, 1953, an earthquake with a strength of ML = 5.3 on the Richter scale shook the area around Widdershausen. As a result of the earthquake, a large part of the northern field, the main extraction field at that time, was damaged as the overburden above pit field 38 suddenly sank and the supporting pillars that had remained standing were shattered. Several buildings in Widdershausen were damaged or destroyed, and a passenger train derailed between Widdershausen and the Wintershall potash plant. In the municipality, the surface of the earth fell by up to two meters. There were no human lives to be complained about, especially because no one was in the affected mine field at the time of the accident. The damage to property was estimated at around three million German marks . The trigger for the rockfall was an incorrect calculation or the underdimensioning of the supporting pillars between the excavation chambers at that time.
Rockfall of Völkershausen in 1989
On March 13, 1989, a planned blast in the pit of the potash mining company Ernst Thälmann led underground to a large-scale collapse of a mining field and at the same time on the surface to an earthquake with a magnitude of ML = 5.6 on the Richter scale.
Others
During the process of unloading chlorine from a rail tank car at the Wintershall potash plant, the filling line broke into the plant's tank on July 2, 1955 because the locomotive started too early. At an overpressure of 8 bar, a huge cloud of chlorine gas escaped and drifted eastward over the ground. Several places, including Widdershausen, had to be temporarily evacuated and 62 injured people had to be hospitalized.
logistics
Rail transport
The establishment of the potash shafts and works was accompanied by a massive expansion of the region's rail network, which until the turn of the century (19th / 20th century) consisted only of the narrow-gauge Feldabahn Bad Salzungen– Kaltennordheim with a branch line to Vacha. The closest connection to the standard gauge network was in 1900 at Bad Salzungen and Gerstungen stations .
After the first discoveries of potash at Kaiseroda and Heringen, there was a great need for transport capacities for the delivery and removal of building materials, labor and raw materials. So began the construction of standard-gauge railway lines from Bad Salzungen and Gerstungen.
The shafts at Dankmarshausen, Widdershausen, Heringen and Philippsthal were opened up via the Gerstungen – Vacha railway line , which was opened in several sections: The rail traffic between Gerstungen and Berka was on October 1, 1903, between Berka and Dankmarshausen on December 1, 1903 between Dankmarshausen and Heringen on March 30, 1905 and between Heringen and Vacha on October 1, 1905. Almost simultaneously, the narrow gauge at this time as Feldabahn was railway line Bad Salzungen-Dorndorf-Vacha on standard gauge rebuilt and put into operation in 1906; parallel to this, a works railway was built between the Dorndorf and Merkers potash works. The Dorndorf (Rhon) station has been substantially expanded and served as a lane change to the station initially continue to narrow-gauge line to Kaltennordheim. From 1906 there was a continuous rail connection Gerstungen-Vacha-Bad Salzungen which opened up all potash plants (Heringen, Philippsthal, Dorndorf, Kaiseroda, from 1925 Merkers). Vacha became a railway junction and received its own depot . The shafts at Dietlas, Menzengraben and Springen outside the Werra valley were (initially) connected by cable cars (see below). The development of the shafts in Unterbreizbach and Buttlar took place in the course of the construction of the Ulstertal Railway , which was opened between Vacha and Geisa on August 1, 1906 and between Geisa and Tann (Rhön) on October 1, 1909 and in Tann connected to the line opened in 1891 after Hilders had.
The Wenigentaft- Oechsen Railway was opened on August 15, 1912, branching off the Ulstertal Railway at Wenigentaft, specifically to develop the Heiligenmühle and Mariengart potash shafts near Oechsen . The Dippach, Alexandershall and Abteroda shafts were connected to the Vacha-Heringen-Gerstungen line at Berka / Werra, which branched off from the main line south of Berka, crossed the Werra and then passed Dippach to the Alexandershall shaft.
The consequences of the Second World War brought drastic changes in rail traffic. Just as the division of Germany cut up the potash district, the rail network that crossed the national border, which had become the inner-German border , was also interrupted. From 1952 there was no longer any traffic between Vacha and Philippsthal, the Ulstertal Railway and, as a result, the line to Oechsen were shut down and dismantled in 1952/53. To make the potash factory in Unterbreizbach more accessible, a railway line from Vacha via Sünna to Unterbreizbach was built in just 90 days in 1954.
The route from Gerstungen to Heringen played a special role, as the Hessian works would have been disconnected from the railway network without this connection. 14.75 kilometers of the 17.8-kilometer-long section between Dankmarshausen and Vacha with the railway stations Widdershausen, Heringen (Werra), Heimboldshausen and Philippsthal lay in Hessian territory and, bordered on both sides by the Soviet occupation zone and later the GDR, only crossed the in Heimboldshausen confluence with Hersfeld Kreisbahn directly connected to the western railway network. At that time, a total of 170,000 tons of fertilizer and considerable amounts of table salt were stored in the two potash stations in Heringen and Heimboldshausen. The transport of the potash from the Heringen and Wintershall plants was not economical over the route that was not designed for this purpose. In 1946, representatives of the Soviet and American occupation zones negotiated a use of the Thuringian section between Dankmarshausen and Gerstungen (and further on the Thuringian Railway towards Bebra ). Nevertheless, due to the political tensions until 1969 there were repeated interruptions in the navigability of this section of the route for western potash trains. In order to bridge the temporary blockage of traffic by the GDR, the Hersfeld Kreisbahn was upgraded for potash traffic and remained in operation after the transport via Gerstungen was regulated between states and permanently possible from September 28, 1969.
With the German reunification, the transport situation eased, the Hersfeld circular path soon became superfluous and closed. Initially, the aim was to close the gap between Philippsthal and Vacha, but this failed because of the land on the railway line that has since been sold and developed. The connection to the Unterbreizbach plant, which now belongs to K + S, was problematic, as the bypass railway to Vacha, built in 1954, was ailing and due to the inclines of little capacity. They referred to plans from the 1930s and in 1999 built a connecting curve from Heimboldshausen to Unterbreizbach, so that the bypass route via Sünna was dispensable and the entire potash traffic was now handled via the route to Gerstungen. Potash traffic via Vacha thus ended in 1999. Since the Dorndorf and Merkers plants were also no longer in operation, demand for the Bad Salzungen-Vacha railway line collapsed and the line was shut down in 2001.
Cableways
The shafts, which could not (yet) be connected to the railway network, were in part connected to the factories and loading stations in the Werra Valley with cable cars . In 1905, the Menzengraben and Dietlas shafts were connected to the first Dorndorf potash factory by a cable car in the Grand Duke of Saxony's union, which was in operation until the Dietlas shaft was closed. When shaft I of the Heiligenroda union went into operation in 1909, it was initially connected to the Wintershall potash plant with a 6550 m long cable car. Further cable cars led from shaft I and shafts IV and V of the Heiligenroda union to shaft II and III. to Springen, from which the 3.5 kilometer long Kaliseilbahn Springen – Dorndorf was put into operation in 1913. This was also the last surviving cable car when it was shut down and dismantled in 1990/1991.
Environmental impact
Heaps
Quite quickly after the start of the potash extraction, it was necessary to sensibly remove the residues from potash mining, so that spoil heaps were created near the potash works . So alone in the Werraaue between Bad Salzungen and Vacha Halden among others at Hämbach , Merkers and Dorndorf , the z. T. as artificial mountains shape the landscape to this day. There were also ash heaps, which were used to deposit the ash from the power plants belonging to the potash plants. Some of these heaps are now closed, recultivated and some of them have been released from mining supervision.
The two heaps at Philippsthal ( Hattorf heap ) and Heringen are still used as the central overburden deposit , with the latter known from afar as Monte Kali .
Precipitation water accumulates on the heaps, in which the salts dissolve and which then accumulates as saline wastewater. This has the potential to flow into the groundwater or surface waters and contaminate them with salt. The chemical additives contained in the spoil heaps and used in the processing of crude salt are seen as a further problem, their environmental toxicological relevance is disputed. Environmentalists are concerned that these substances will also find their way into watercourses via rainwater.
sewage
Sewage sinking
In order to dispose of the salty wastewater from potash extraction and processing as harmlessly as possible, it was first started in 1925 to inject this wastewater into the subsoil ( injection ). The groundwater-rich plate dolomite above the potash deposits was considered suitable for absorbing and storing the wastewater without damage. The first sinking wells were put into operation for the Merkers plant in 1925 in the Werraaue near Tiefenort . Since then, a billion cubic meters of saline waste water were approximately in the dolomite pressed .
Further sinkings took place near Springen and after 1945 in the Horschlitter Mulde near Berka / Werra , as well as in Hesse near Heringen and Bodesruh . The sudden increase in the salt content in wells in the Berka / Werra area led to the sewage sinking in the GDR being stopped in the 1960s and all salty sewage being fed into the Werra.
After 1990 efforts were made to sink wastewater again at Herda and Gerstungen , after a test phase, the Thuringian State Mining Authority did not obtain the necessary approval due to the incalculable risks for the aquifer above the dolomite in the red sandstone , some of which are used for the public drinking water supply granted. The Kassel regional council, however, extended the permit for the sinking in the East Hessian part of the potash district until the end of 2015.
Introduction to the Werra
In parallel with the sinking of the wastewater underground, saline wastewater is discharged into the Werra watercourse. The long-term basis for the discharge is a water law permit from 1942, which provides, among other things, that at the gauge in Gerstungen, below the last of several discharge points of the five potash works in the Werra district, a limit value of 2500 mg / l chloride in the water of the Werra is not may be exceeded. This limit value was adopted unchanged in all subsequent decisions up to 2009.
From 1968 the three Thuringian potash mines after the complete cessation of the sewage sinking in Thuringia no longer adhered to the limitation of the salt water discharges into the Werra and increased their salt output considerably ecological damage to the Werra and Weser ecosystems . The formerly typical freshwater ecosystem of the Werra and Weser had conditions similar to brackish water in times of heavy salt pollution . With the closure of the Merkers and Dorndorf plants, a reduction in discharge quantities and compliance with the limit value that was still in force in 1942, significant improvements in water quality have been recorded since 1999. Compared to the situation in the 1980s, the Werra's salt pollution has been reduced by around 80 percent, and formerly native freshwater species have returned to the Werra and Weser.
On November 30, 2012, the Kassel regional council granted K + S a new water law permit for the discharge of saline wastewater into the Werra. In the permit, the wastewater quantities and parameters are to be gradually reduced by 2020. Among other things, the limit value for chloride, which has remained unchanged since 1942, is to be reduced to 1,700 mg / l from 2015 and the amount of waste water to eight million cubic meters per year. Even with the stricter limit values, critics see it as impossible to achieve the quality goals of the EU Water Framework Directive by 2020.
Future sewage disposal
Due to the ongoing criticism of the current disposal practice and due to the fact that the previous disposal practice can no longer be permitted due to the objectives of the Water Framework Directive, alternative disposal variants have been increasingly discussed since around 2007. In March 2008 a round table with representatives from the potash industry, environmental associations, politics and experts was set up to develop and make recommendations on future disposal practices. Some of the experts see possible disposal alternatives in the evaporation of the wastewater on site, the experts at the Round Table issued a recommendation in 2010 that provided for a series of individual measures to reduce and discharge wastewater, including a pipeline to the North Sea . From the company's point of view, the on-site evaporation of wastewater is not feasible, the pipeline to the North Sea met with resistance from politicians from Hesse, North Rhine-Westphalia and, above all, Lower Saxony , which would have to grant permission under water law for discharge into the North Sea. In September 2014, the Hessian Ministry for the Environment, Climate Protection, Agriculture and Consumer Protection presented a study according to which the requirement for the construction and operation of the sewer pipeline was not economically justifiable and therefore disproportionate.
ground
The drifting of salts near heaps and transport routes has widespread salinisation of the soil and thus a change in vegetation, which often promoted soil erosion and the settlement of salt plants .
Due to the closure of potash shafts and works, combined with the dismantling of transport routes and the technical improvement of the remaining production and transport logistics, a decrease in salts on the soil and thus on the salt vegetation has been recorded.
Web links
- Potash districts of Unstrut, Südharz and Werra
- Widdershausen.de - History of potash mining near Heringen
Individual evidence
- ^ Rhön Lexicon , accessed on January 22, 2014.
- ↑ Jörg Lessing: A misfortune out of nowhere. Geological features section . In: inSüdthüringen.de. October 3, 2013, accessed January 22, 2014.
- ^ "125 years of potash mining in the Werra Valley" in Südthüringer Zeitung , local section Bad Salzungen from September 22, 2018
- ^ History of Potash and Salt , accessed on August 19, 2014.
- ^ Citizens' Association Dorndorf (ed.): Festschrift 1225 years Dorndorf / Rhön . Self-published, Dorndorf 2011, p. 51-53 .
- ^ Greg Bradsher: Nazi Gold. The Merkers Mine Treasure. In: Prologue. Retrieved December 8, 2013 (English, No. 1, Spring 1999).
- ^ Frank Baranowski: Abteroda men's camp. BMW ("Bär / Anton"). In: nszwangsarbeit.de. 2004, accessed September 25, 2015 .
- ↑ locations. Europe. K + S, accessed on January 23, 2014.
- ↑ Christoph Schmidt-Lunau: Potash mining in Hesse and Thuringia: Too much salt flows into the Werra . In: The daily newspaper: taz . May 16, 2018, ISSN 0931-9085 ( taz.de [accessed May 17, 2018]).
- ↑ Ilga Gäbler: Three who experienced the gas accident. May 24, 2013. Retrieved October 5, 2013 .
- ↑ The earthquake in Widdershausen in 1953. ( Memento of the original from October 21, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. In: widdershausen.de. Retrieved January 22, 2014.
- ↑ Ralf Roman Rossberg : Border over German rails 1945–1990. EK-Verlag, Freiburg 1991.
- ^ Ludwig Brake: The first railways in Hessen. Historical Commission for Hesse, Wiesbaden 1991.
- ↑ Construction of the cable car from Heiligenroda I to Wintershall in 1909. In: widdershausen.de Retrieved on January 20, 2014.
- ^ Potash mining and salinization. Project “Lebendige Werra”, a joint project by BUND, DUH and NABU. Retrieved May 2, 2010.
- ↑ November 2011.pdf Lowering permit . ( Page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. dated November 30, 2011 (PDF).
- ↑ Torsten Wegener: Both solutions are bad. In: NW-News.de. May 25, 2011, accessed January 23, 2014.
- ^ Salt exposure of the Weser. NLWKN, September 24, 2013, accessed January 24, 2014.
- ↑ The new limit values. Statement by the Werra-Weser Neighboring Conference e. V. on the discharge permit dated November 30, 2012. Press release from the Werra-Weser Neighboring Conference, December 6, 2012, accessed on January 23, 2014 (PDF).
- ↑ Werra Round Table ( Memento of the original dated February 7, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , accessed September 24, 2014.
- ↑ Study presents alternative to dumping K + S potash waste water. on: Focus online. accessed on September 24, 2014.
- ↑ Recommendation of the Round Table ( Memento of the original from October 29, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , accessed September 24, 2014.
- ↑ Potash plant not feasible without wastewater. In: HNA. accessed on September 24, 2014.
- ↑ Salt should stay where it is. In: Mindener Tageblatt. accessed on September 24, 2014.
- ↑ Hessen no longer wants a potash pipeline. In: HNA. accessed on September 24, 2014.
- ↑ Cornelia Schuster, Ronald Bellstedt , Klaus Schmidt: Flora, fauna and development of the inland salt stations in the Wartburg district . Ed .: District Office Wartburgkreis (= nature conservation in the Wartburgkreis . Issue 16). 2010, p. 35 ff .
