History
The Gewerkschaft Bonifacius in Buttlar had secured exploration rights over the Geisaer Amt in the Ulstertal and had sunk preliminary borings at Geisa (borehole no. 7), Kranlucken (borehole no. 6), and Borsch (borehole no. 5). On 19 December 1908 the Gewerkenversammlung of the Gewerkschaft Bonifacius authorised the detachment of 8 to 10 northern fields, which were sold to a banking consortium (Bankhaus Hermann Schüler and A. Hornthal) in summer 1910 for 50,000 Mark in cash and 1,000,000 Mark in five per cent bonds. This detachment was used to establish the Gewerkschaft Buttlar, which was formally founded on 1 October 1910 and entered in the Handelsgericht on 11 October 1910. A Konzession to discharge treated effluent from a daily processing capacity of about 4,530 Doppelzentner of carnallite into the Ulster had already been granted. A Interessengemeinschaft (community of interest) was established with the Gewerkschaft Bonifacius in Buttlar.
In 1906 a site north of Buttlar at the Frankfurter Straße had already been acquired for the planned shaft installation. A provisional rail connection from the Haltepunkt Buttlar on the Ulstertalbahn to the shaft site was approved by the Königliche Eisenbahndirektion Erfurt on 21 December 1906. The Ulstertalbahn served the section between Vacha and Geisa from 1 August 1906 and between Geisa and Tann from 1 October 1909, providing the connection to the Werra valley.
Shaft sinking began in 1910–11. Surface buildings erected on the site included a cable and pithead baths building (Kabel- und Kauengebäude), a winding machine house, a workshop building, a shaft tower, and a steam winding machine building. On 28 October 1913 a catastrophic accident occurred during sinking: the tübbing column between 344 and 348 metres depth broke apart and collapsed into the shaft onto the sinking gang working below. Six miners were killed and several were seriously injured. From 1914 to 1918 only maintenance work was carried out. The shaft had reached a depth of 408 metres by the time sinking was halted on the outbreak of war in 1914, without having broken through the Plattendolomit layer to reach the underlying potash seam. After the war ended the teufarbeiten were not resumed. In January 1922 the Grubenvorstand resolved to close the works.
In October 1924 an application was lodged to cap the shaft with a concrete cover. The shaft remained unfilled from 300 metres upward to the surface. With the closure of the works in 1922 part of the shaft lining was dismantled. The Gewerkschaft Buttlar was dissolved on 20 September 1926 and its assets transferred to the Kali-Industrie AG at a rate of 56 Reichsmark per Kux in Kali-Industrie shares; the transfer took effect from 19 March 1927. The Elektrizitätswerk and boiler house were taken over by the Überlandwerke Rhön and the Württembergische Elektrizitäts AG after the closure.
Before the Second World War it was considered whether the Schacht Buttlar could serve as a second exit shaft for the Kaliwerk Unterbreizbach; this idea was revisited in 1951 but rejected because of unfavourable hydrogeological, mining-technical, and economic conditions. The second shaft for Unterbreizbach was ultimately sunk at Mühlwärts instead.
During the Second World War some buildings were used as a Wehrmacht depot. After 1945, following the founding of the DDR, a Landwirtschaftliche Produktionsgenossenschaft (LPG) occupied the site. Part of the northern area was levelled with rubble from the demolished Ziegelei Wenigentaft. From the early 1970s a Mischfutterwerk (animal feed mixing plant) was established on the site.
As of recent documentation the surviving structures at the Gewerkschaft Buttlar site comprise: the shaft head itself (covered), a storage building, and the former boiler house and electrical generating building. The former chimney was demolished in the 1950s. The former cable and pithead baths building or magazine survives as a storage building now in use by a tyre company. The shaft currently serves as a source of process water (Brauchwasser).