Active potash mine personnel shaft at Philippsthal (Werra), serving as the principal access point for underground workers at the Verbundbergwerk Werra, with the steel headframe of the Schachtanlage Heimboldshausen-Ransbach (HeRa) operating continuously.
The Schacht Ransbach forms one half of the Doppelschachtanlage Heimboldshausen-Ransbach, also known as HeRa, located at the Nippe between the communities of Heimboldshausen and Ransbach, a short distance from the main Kaliwerk Hattorf site at Philippsthal (Werra). The two shafts were planned in 1909 when the Generalversammlung of the A.-G. Kaliwerke Hattorf resolved to construct two further shaft installations. The dual investment was motivated by the Zweischachtverordnung — the regulatory requirement for every mine to maintain a second access point — and by the quota policies of the Kali-Syndikat.
Sinking of Schacht Heimboldshausen began in December 1909; work on Schacht Ransbach began approximately eighteen months later, in mid-1911. Both shafts entered service in 1913 and were operationally linked by an underground breakthrough. Schacht Heimboldshausen reached a final depth of 803 metres and Schacht Ransbach 810 metres.
During the Second World War the underground workings of the HeRa complex were used for the storage of cultural and scientific materials including library collections. After a period of post-war closure and clearing, both shafts were reactivated: Schacht Heimboldshausen became a ventilation shaft and Schacht Ransbach became the sole personnel-transport shaft for the entire underground workforce of the Kaliwerk Hattorf. Schacht Ransbach today serves approximately 1,200 miners entering and leaving the Verbundbergwerk Werra workings at depths of 750 to 800 metres, with the winding cage carrying 98 miners on four decks at 40 kilometres per hour.
The decision to develop two further shaft installations at the Nippe, approximately two kilometres from the main Kaliwerk Hattorf site, was taken by the Generalversammlung of the A.-G. Kaliwerke Hattorf in 1909. Two motivations are recorded: the Zweischachtverordnung requirement for a legally mandated second mine access, and the quota allocation strategy of the Kali-Syndikat, which used shaft capacity as a basis for production quotas. The Gewerkschaft Heimboldshausen was founded on 16 June 1909 by separation of part of the concession fields of the Kaliwerke Hattorf, and the Gewerkschaft Ransbach was founded on the same date by the same mechanism.
Sinking of Schacht Heimboldshausen began in December 1909 at a site called die Nippe, with the Schacht Heimboldshausen (also designated Schacht I of the HeRa complex) reaching a final depth of 803 metres. The second shaft, Schacht Ransbach (designated Schacht II), was taken in hand approximately eighteen months later. Both shafts entered service in 1913. Surface facilities including the Tagesanlagen and the Chlorkaliumfabrik were constructed jointly for both shafts by the two Gewerkschaften. The Eisenbahnanschluss for the HeRa complex used the Kreisbahn Hersfeld–Heimboldshausen (later the Hersfelder Kreisbahn), which was opened on 26 September 1912 on the route from Bad Hersfeld to Heimboldshausen, and which served the Kaliwerk Hattorf and the HeRa shaft installations along its route. A station at Ransbach was part of the railway alignment. The underground workings of the two shafts were connected by a breakthrough to the Hattorf main field.
During the period of the Stillegungsverordnung after the First World War, the HeRa installations were placed on standby along with other unproductive Kali-Syndikat facilities. A station at Heimboldshausen opened in 1917 to serve the mine workforce; after the shaft was shut down following 1920 the station building was removed.
During the Second World War, the underground workings of the Schacht Heimboldshausen and Schacht Ransbach complex became a repository for cultural and scientific collections: the Staatsbibliothek materials from Berlin were transported to the site by canal barge and then by forced labour, with a total of approximately 230,000 volumes brought from Marburg alone between July and September 1944. Shortly after the arrival of US Army forces a fire broke out in the newspaper holdings of the Staatsbibliothek underground; arson was suspected but never proved. The smouldering section was walled off and only cleared and recovered in May 1946. A military engineering officer named Bergassessor Kramm, whose brother was a librarian in Berlin and Breslau, was stationed at Schacht Ransbach and was responsible for the salvage operation.
Following the post-war munitions clearing period and the political reorganisation of the Western occupation zones, the Doppelschachtanlage HeRa was reactivated to serve the Kaliwerk Hattorf. German division had significantly altered the logistical situation for the Werra potash mines: the rail line between Vacha and Philippsthal across the inner-German border was interrupted from 1952, requiring rerouting of coal and salt transport via the Hersfelder Kreisbahn between 1952 and 1954 and again between 1967 and 1969. Schacht Heimboldshausen was put back into operation as a ventilation shaft (Wetterschacht), while the newly reactivated Schacht Ransbach assumed the function of sole personnel-transport shaft (Seilfahrschacht) for the complete underground workforce of the Kaliwerk Hattorf. This arrangement removed the need for miners to share the production shaft facilities at the main Hattorf site, eliminating interference between winding operations.
Today Schacht Ransbach, operating within the Verbundbergwerk Werra, is one of the principal Seilfahrtschächte through which approximately 1,200 underground workers access the Werra field daily. The winding cage accommodates 98 miners on four decks and descends at 40 kilometres per hour to depths of 750 to 800 metres. The steel headframe of the HeRa installation is visible from the Nippe site; red-brick pithead buildings remain on the shaft compound. The Verbundbergwerk Werra ventilation system draws 100,000 cubic metres of fresh air per minute through Schacht Ransbach and the other intake shafts combined.