Former potash mine at Hambühren in the Landkreis Celle, voluntarily closed in 1926 after only a few years of operation; the surviving pithead buildings — an office, machine house, Kaue, workshop, and Fördermaschinenhaus — remained in good condition into t
The Schacht Hambühren was a potash mine shaft in the Gemarkung Hambühren, in what is today the Samtgemeinde Hambühren, Landkreis Celle, Niedersachsen. Its formal operating entity, the Bergbaugesellschaft Hambühren m.b.H., was in practice a controlled subsidiary of the neighbouring Kaliwerke Prinz Adalbert A.G., which had separated part of its Berechtsame (concession field) in the Gemarkungen Hambühren, Oldau, and Südwinsen around the start of 1911 specifically to obtain additional Kali-Syndikat production and sales quotas. The shaft was sunk using the Gefrierverfahren from 29 December 1911; the salt deposit was first encountered at 102 metres depth.
Work was interrupted in 1918 under a wartime order (kriegsamtliche Anordnung). The shaft reached its final depth of 711 metres on 5 September 1915; cast-iron tubbing extends to 163.4 metres and brick or reinforced-concrete lining below. An underground breakthrough to the Kaliwerke Prinz Adalbert exists at the 640-metre level.
Surface facilities were built between 1913 and 1915 and comprised the essential structures only: an office building, machine house, Kaue, workshop, a Fördermaschinenhaus with a 35-metre headframe supplied by the Firma Eilers of Hannover, a small Schachthalle erected in 1922, a narrow-gauge railway to the Prinz Adalbert shaft, and a salt spoil heap connected to the shaft by a 5.50-metre-high, 22.50-metre-long spoil-bridge. The mine was voluntarily closed (freiwillige Stillegung) in 1926, having produced Rohsalze that could not be brought to market within the available Kali-Syndikat quota. The pithead buildings were noted by a visitor in 1982 as still in use by an industrial tenant.
The formal origins of the Schacht Hambühren lie in a Feldesteilung — a field separation — that the Kaliwerke Prinz Adalbert A.G. executed at the beginning of 1911. The company partitioned the portion of its Gerechtsame (concession) lying in the Gemarkung Hambühren from the remaining field in the Gemarkungen Oldau and Südwinsen. The separated field was assigned to a new legal entity, the Bergbaugesellschaft Hambühren m.b.H., which was nominally an independent company but was entirely under the Verfügungsgewalt (operational control) of the Kaliwerke Prinz Adalbert. The purpose of creating this nominally independent mine was to obtain further Kali-Syndikat Förder- und Absatzquoten: the Syndikat awarded quotas to shaft installations, and a formally separate shaft could therefore draw a full additional quota, even if it was physically and commercially linked to a larger neighbouring operation.
The decision to locate the shaft in Hambühren was informed by two shallow boreholes that had encountered Steinsalz at 102 metres depth, confirming proximity to the salt stock. Sinking of the Schacht Hambühren began with the excavation of a 4.60-metre-deep starter pit on 29 December 1911. The Gefrierverfahren (ground-freezing method) was employed, as had been used at the adjacent Schacht Prinz Adalbert. Freezing operations began on 20 November 1913, five weeks before the main sinking commenced; by April 1914 the shaft had been lined with tubbing to 149 metres and in May 1914 the full depth of the freeze section (225 metres) was reached. Work continued during the early part of the First World War; despite the general mobilisation on 1 August 1914, sinking proceeded until 5 September 1915, when the Endteufe of 711 metres was achieved. The shaft stands in cast-iron tubbing from the surface to 163.4 metres and in masonry or reinforced-concrete lining below. Operations were required to cease in 1918 by a kriegsamtliche Anordnung (wartime authority order).
The surface facilities, built between 1913 and 1915 in parallel with shaft sinking, comprised only the structures considered strictly necessary for a shaft that functioned more as a Notausgang (second mine exit) and quota-generating installation than as an independent mine: an office building, machine house, Kaue, workshop, a Fördermaschinenhaus with a 35-metre-high headframe (Fördergerüst) supplied by the Firma Eilers of Hannover, and two residential flats for a Beamter and two workers respectively. In 1922 a small Schachthalle of 10 × 15 metres was added above the shaft mouth. A narrow-gauge Schmalspurbahn connected the Hambühren shaft with the Schacht Prinz Adalbert approximately 1.5 kilometres to the west, transporting raw salt between the two sites. A small salt spoil heap (Salzabraumhalde) served the shaft via a miniature bridge structure 5.50 metres high and 22.50 metres long. An underground breakthrough to the Kaliwerke Prinz Adalbert was achieved on the 640-metre level.
The quota for the Schacht Hambühren was formally transferred to the Kaliwerke Prinz Adalbert during the Kali-Syndikat rationalisation of the post-First World War period. The mine was voluntarily closed — freiwillige Stillegung — in 1926, after the extracted Rohsalze proved impossible to market profitably within the available Syndikat quota. The Baumgarten shaft record states simply that the voluntary closure took place in 1926 and that the quota had been transferred to Prinz Adalbert. A visitor to the site in 1982 reported that the former pithead buildings were still occupied by a commercial tenant, that the shaft opening was visible from the adjacent works yard, and that the buildings were well preserved; a comment from 2021 expressed the view that the surviving buildings were 'quite remarkable' and that Denkmalschutz (heritage listing) would be appropriate.