Former potash mine shaft at Heringen (Werra), active for only twelve years before closure under the 1923 Stillegungsverordnung, now surviving as a ventilation shaft with red-brick surface buildings, central workshop, and the Werra-Kalibergbau-Museum occup
The Schacht Heringen is a former potash mine shaft at Heringen (Werra), sunk from 1907 as a dual-purpose installation: the legally required second shaft (Zweischachtanlage) for the adjacent Kaliwerk Wintershall, and a Quotenschacht to increase the Wintershall group's Kali-Syndikat allocation. The Gewerkschaft Wintershall resolved in 1907 to divide its concession field and erect the Schacht Heringen as a formally independent shaft installation to serve both regulatory functions. The underground breakthrough between the Schacht Heringen and the Schacht Grimberg (Wintershall) was achieved on 1 April 1912.
Potash production commenced in 1913 and continued for only twelve years: the Stillegungsverordnung of 1923, which drastically reduced the number of active German potash mines, required the Schacht Heringen to cease production. A rail connection across the Werra linked the site to the main Wintershall works from 1911. In the 1950s, all hoisting equipment including the headframe was dismantled and the shaft was retained purely as a Wetterschacht (ventilation shaft).
The surface buildings — constructed in red brick to match the main Wintershall works — remained in active use: until 1992 the Schacht Heringen site was the location of the centralised apprentice training programme for the entire Wintershall group. The Zentralwerkstatt (central workshop) of the K+S Verbundbergwerk Werra is still based there today. The Werra-Kalibergbau-Museum, which documents the history of potash mining across the Werra-Fulda Kalirevier, is located in the former pithead buildings of the Schacht Heringen site.
The decision by the Gewerkschaft Wintershall to establish the Schacht Heringen was recorded on 1 June 1907, when the first Spatenstich for the new shaft was made. The motivation was twofold. The Zweischachtverordnung of 1903 required every mine to have two separate surface exits, and the Kali-Syndikat's quota system allocated production entitlements by shaft capacity: a second formally separate shaft installation would therefore double the Wintershall group's productive quota allocation, provided the shaft could demonstrate actual output. The Gewerkschaft Wintershall divided its concession, separating the field that would be attributed to the Schacht Heringen from the main Wintershall field.
Sinking progressed through the Buntsandstein and Plattendolomit; a connection along the rail network across the Werra was completed in 1911 to link the shaft site to the main Wintershall works. The underground breakthrough between Schacht Heringen and Schacht Grimberg (Wintershall) was completed on 1 April 1912. Potash hoisting commenced in 1913. The Kali-Syndikat Beteiligungsziffer for the Schacht Heringen was recorded at 6.0154 Tausendstel as of 1 May 1921. The mine's Gerechtsame extended across the parishes of Heringen, Wölfershausen, and adjacent Gutsbezirke, covering approximately 6 Prussian maximum fields. The potash seam had a thickness of 2 to 3 metres.
The production phase was short. The Stillegungsverordnung of 1923 — the German government's response to the collapse of the export-driven potash market — required a significant reduction in the number of active Kali operations. The Schacht Heringen was among those ordered to cease production, having hoisted potash for only twelve years in total. The surface buildings, constructed in red brick consistent with the aesthetic of the main Wintershall works, were retained for other functions after the closure of hoisting operations.
In the 1950s, the complete hoisting installation — including the Fördergerüst — was dismantled and removed. The shaft was retained in service as a Wetterschacht, providing ventilation for the expanding underground workings of the combined Wintershall-Grimberg field. The pithead surface complex found continued use as the principal training centre for apprentice miners across the Wintershall group's operations; this centralised Lehrlingausbildung continued until 1992. The Zentralwerkstatt (central workshop) servicing the equipment of the Verbundbergwerk Werra is still located at the Schacht Heringen site.
The Werra-Kalibergbau-Museum, which documents the history and present state of potash mining across the Werra-Fulda Kalirevier on both the Hessian and Thuringian sides of the former inner-German border, occupies the former pithead buildings of the Schacht Heringen installation. The museum was closed temporarily from early 2025 for renovation works, with its expected reopening announced for early 2027.