Potash production came to an end after 120 years

On December 21, 2018, potash mining at the Sigmundshall plant came to an end. After almost 120 years of potash mining, the economically recoverable reserves have been exhausted and the work at depths of between 1,100 and 1,400 meters is pushing people and technology to their limits.

Apart from the required securing work, which will take several more years, K+S is develwould like to develop the site into an innovation center for testing and establishing new business areas.


The history of the Sigmundshall plant

Zechenhof 1904

With its 120-year history, Sigmundshall is not only a reflection of current events, but also illustrates the turbulent development of German potash mining.

Industrial history

1898 - Sigmundshall shaft is drilled in the middle of the "potash boom" of the late 19th century. It is one of more than 200 potash shafts in the German Reich.

1906 - Construction of the potash factory and start of fertilizer production

1913 - The Weser shaft in Altenhagen is drilled and connected to the Sigmundshall mine in 1914. Potash mining at "Gebrück" (approx. 1920s).

1933 - Closure of the plant within the framework of state control of production

1949 - Resumption of production as a replacement for lost potash plants in Central Germany

1960 - Start of molten salt production for metallurgical applications

1965-1969 - Drilling of the Kolenfeld shaft and extension of the Kolenfeld shaft to a weather and material shaft

End of the 1960s - Introduction of trackless winding machines and rapid mechanization of extraction work.

At the end of the 1970s - performance increase of the line conveyance by large-capacity wagons. Annual production exceeds 2 million tonnes (1979).

1992 - Construction of a plant for the recycling of aluminum salt slags (REKAL)

The Husum shaft project northwest of the Steinhuder Meer is abandoned because the reunification had fundamentally changed the structure of the German potash industry.

1995 - Start of tailing pile coverage with REKAL residue and greening

1997 - Reached 1,400 meters

1999 - Construction of a new production line for the manufacture of fertilizer specialties based on hard salt/Kieserite

2001 - Start of Kieserite production and use of the Staßfurt seam (hard salt) as an additional crude salt base, thus extending operating life

2003 - Annual production for the first time exceeds 3 million tonnes

2007 - Introduction of series construction machines for line haulage in mine operations

2014 - The extraction of crude salt is almost exclusively shifted to the 1,150 to 1,400 meter level. Temperatures of up to 50 °C prevail there.

November 2017 - The K+S Board of Executive Directors decides to discontinue salt production and potash production at the end of 2018, as economic operation is no longer possible. The employees affected by the closure were offered new jobs at other company sites.

Dec. 21, 2018 - Potash production at the Sigmundshall plant ends with the production of the "last ton". Between 1904 and 2018, a total of about 130 million tonnes of crude salt were extracted from the Bokeloh salt dome and processed into fertilizers and industrial products.

from 2019 - The site will be developed into an innovation center for testing and setting up new business activities.

The REKAL plant will continue to produce to the same extent as before; the recycling waste generated there will continue to cover the tailings pile. The greening of the tailings piles is to be completed by approx. 2037.

The mine will be secured and prepared for the subsequent flooding, which is required for disused salt mines in Lower Saxony.

K+S is continuing the ongoing training of industrial mechanics, electronic technicians and chemical technicians and will also hire nine new trainees in 2019 to cover its own demand for qualified specialists.  From 2020, only the apprenticeship of chemical technicians will be continued.


International standards & norms

Our products are certified according to international standards and norms. Here you can find our current certificates.

ISO 50001 Certificate K+S Aktiengesellschaft

K+S Aktiengesellschaft Certificate with enclosure

ISO 50001 Certificate

K+S Minerals and Agriculture GmbH

ISO 9001 Certificate

K+S Minerals and Agriculture GmbH

Certificate Qualified Waste Management

REKAL-Sigmundshall plant
Contact & Route

Your contact

If you have any questions about the Wunstorf site, please use our contact options and we will take care of your request immediately!

Christina Bauch
K+S Minerals and Agriculture GmbH Potash mine Sigmundshall
Waste management
Training site
Tienberg 25
31515 Wunstorf
+49 5031 104 2407
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