Active potash mine at Neuhof in the Landkreis Fulda, operating as the Kaliwerk Neuhof-Ellers of the K+S group since the 1950s, with Schacht II (Ellers) serving as the principal personnel access shaft at approximately 533 metres depth.
The Kaliwerk Neuhof-Ellers is a potash mine located in the Werra-Fulda Kalirevier at Neuhof, Landkreis Fulda in Hessen, operating as the southernmost mine of the K+S group and one of two active Kali-Werke outside the Verbundbergwerk Werra. The mine's origins lie in the concession work of Fedor Siegel, who obtained the Bergwerkseigentum for the Siegel II field in the Oberförsterei Neuhof and the Gemeinde Ellers on 23 November 1905. The first shaft — named the Schacht Wilhelm von Recklinghausen and subsequently known as Schacht Neuhof — began sinking in January 1906 under the Gewerkschaft Neuhof, Kaliwerke zu Neuhof-Fulda.
Severe water ingress from the Buntsandstein overburden required extensive cast-iron tubbing; the shaft reached its final depth at a cost of 9 million Goldmark. The Gewerkschaft Ellers — the operating company for Schacht II — was founded on 11 April 1910 by sale of a portion of the Neuhof concession to a banking consortium. Sinking of Schacht Ellers began on 25 March 1912; a water inundation at 275 metres in spring 1913 required cementation, and the First World War caused operations to be suspended in September 1914 at 374 metres depth.
Sinking resumed in 1919 and the underground breakthrough between the two shafts was achieved in October 1920 at approximately 533 metres depth. The mine was placed in standby by the Wintershall AG in 1926–1927 on the orders of August Rosterg. During the Second World War, the underground workings of the Schacht Ellers complex were requisitioned in September 1944 for armaments manufacture for the Adlerwerke of Frankfurt (project code name Schakal), using Italian military internees and Jewish forced labourers under the Organisation Todt; the project was abandoned at the end of March 1945.
The mine was returned to the Wintershall AG in 1952 and rebuilt 1953–1954; production resumed after this reconstruction and the mine has operated continuously since. Annual production is approximately 4 million tonnes of raw salt from which approximately 1.3 million tonnes of finished product is derived.
The potash deposits at Neuhof were first identified through exploration boreholes beginning in 1899–1900, which found the Werra-Formation Zechstein strata to be a viable target in the southern part of the Werra-Fulda Kalirevier. The Bergwerkseigentum for the field designated Siegel II was formally granted on 23 November 1905 to the Ingenieur and Fabrikbesitzer Fedor Siegel of Schönebeck. A Betriebsplan was submitted in December 1905 and approved within three days, and the sinking of Schacht Wilhelm von Recklinghausen — the later Schacht Neuhof — began in January 1906. The shaft had a diameter of 5.80 metres internal clear width. Almost immediately the sinking encountered unexpectedly severe water ingress from the Buntsandstein: at 17 metres depth the inflows were already considerable, reaching 5 cubic metres per minute at 70 metres. Repeated pump failures caused delays; high-pressure centrifugal pumps replaced the failing plunger pumps and cast-iron tubbing was used throughout the water-bearing strata. The final depth of the shaft was reached after considerable difficulty, at a total cost of 9 million Goldmark. A Doppelbockfördergerüst was erected above the shaft and the surface facilities were equipped with a Schlagkreuzmühle for grinding the extracted salts. A 2.5-kilometre Werkanschlussbahn connecting the mine to the Bahnhof Neuhof on the Frankfurt–Göttingen line was constructed.
The Gewerkschaft Ellers was founded on 11 April 1910 by the sale of a portion of the Neuhof concession gerechtsame to a banking consortium, separating the Ellers field (approximately 12,000 square metres) from the parent Neuhof holding. Pre-work at the Schacht Ellers site began in 1911, including the construction of Werkstätten-, Magazin-, Kauen- and Verwaltungsgebäude; the Teufarbeiten proper began on 25 March 1912. The shaft also encountered severe water ingress, first at 275 metres in spring 1913, requiring cementation before work could continue. The shaft had reached 374 metres when the outbreak of the First World War forced suspension of operations on 29 September 1914; Emil Sauer, the Gewerkschaft chairman, wrote to shareholders that so many workers and officials had been called up that continuation was impossible. A concrete block was placed at the shaft bottom to secure the workings. Sinking resumed in 1919. In October 1920, the underground Querschlag from the Schacht Neuhof achieved the breakthrough to the Schacht Ellers horizon at approximately 533 metres depth, establishing the underground connection between the two shafts required by the Zweischachtverordnung.
The mine was a member of the Kali-Syndikat and received a quota of 11.46 Tausendstel from its admission. In 1926–1927, however, August Rosterg, the Generaldirektor of the Wintershall AG, caused the mine to be placed in standby (Stillegung) as a rationalisation measure within the Kali-Syndikat framework. This decision attracted controversy within the region, as the mine had become the economic mainstay of the Neuhof community.
During the Second World War, by Verfügung of the Rüstungsstab of 23 September 1944, the Oberkommando des Heeres (OKH) assigned the Schacht Ellers underground workings to the Adlerwerke of Frankfurt am Main for the underground manufacture of tank transmissions under the project code name Schakal, directed by the Organisation Todt. Italian military internees (Italienische Militärinternierte) and persons designated as Halbjuden were employed as forced labourers in the excavation and conversion work. A US Air Force bombing of the Bahnhof Neuhof and the advance of US Army troops in late March 1945 brought the Schakal project to an end. Plans to flood the shafts after the war were initially proposed; from 1946, the stored munitions were cleared by the STEG (Stahl- und Eisen-Treuhandgesellschaft). In 1952 the Wintershall AG received the mine back from the Allied authorities, and resolved — in light of the loss of its former East German Kaliwerke — to resume production at Neuhof. Reconstruction of the underground and surface installations was carried out in 1953–1954; production resumed thereafter.
The mine subsequently passed through the same corporate sequence as other West German potash mines: it became part of the Kali und Salz GmbH in 1970, then the K+S group. Today the Kaliwerk Neuhof-Ellers extracts approximately 4 million tonnes of raw salt annually from the Werra-Formation at depths exceeding 500 metres, employing approximately 680 to 700 workers. The derived annual production is approximately 1.3 million tonnes of potash and magnesium fertiliser products. The Schacht Ellers — designated Schacht II in current K+S nomenclature — serves as the principal personnel-access shaft. Cumulative production at the Kaliwerk Neuhof-Ellers since 1906 reached 200 million tonnes of raw salt and derived products in 2023.