Active ventilation shaft at Ilberstedt, originally a kali mine sunk in 1911 and abandoned in the 1920s, reopened in 1982 as a Frischwetterschacht for the Steinsalzbergwerk Bernburg–Gröna.
The Schacht Ilberstedt, formally named Schacht Johanne, originated as the sole shaft of the independent Gewerkschaft Ilberstedt, sunk by the Deutsche Schachtbaugesellschaft Nordhausen from 1911 and completed in late 1912 at a depth of 575 metres, with the Kalilager intersected at 543.3 metres. The Kalisyndikat allowed extraction from 1 August 1913, but wartime delays meant planmäßiger Abbau was taken up only in 1913 with road development and 1913 with extraction. The Gewerkschaft Ilberstedt was voluntarily liquidated in December 1925 following an agreement with the Kali-Industrie AG, after which the shaft was decommissioned and the surface plant demolished.
Sixty years later, in 1982, the shaft was reopened — without the original surface buildings — as an einziehender Wetterschacht to supply Frischwetter to the north-western field of the Steinsalzbergwerk Bernburg–Gröna, by which time the mine's underground workings had extended north-westward beneath Ilberstedt from the main Bernburg–Gröna complex. Today Schacht Johanne, equipped with a surviving headframe alongside the railway line at Ilberstedt, remains in service as a ventilation shaft for the active Steinsalzbergwerk Bernburg.
The late Wilhelmine Kalibergbau boom, the so-called Kalifieber, stimulated the formation of numerous Gewerkschaften across the Zechstein belt of central Germany. Among these was the Gewerkschaft Ilberstedt, founded on 13 April 1911 in the community of Ilberstedt in the Freistaat Anhalt, holding approximately 8,000,000 square metres of Gerechtsame in the Gemarkung Ilberstedt. The Gerechtsame markschied with the fields of the Preußischer and Anhaltischer Fiskus and the neighbouring Gewerkschaften Anhalt, Coburg, and Erbprinz, and had been partially explored by borings which confirmed Carnallit and Hartsalz deposits.
The sinking of the Schacht Ilberstedt (known also as Schacht Johanne and later Schacht Johanne Ilberstedt) was entrusted to the Deutsche Schachtbaugesellschaft Nordhausen. Teufarbeiten began in 1911; by the end of 1911 a depth of 125 metres had been reached, and by the end of 1912 the shaft stood at 575 metres depth and was betriebsfertig ausgebaut. On 26 August 1912, at a depth of 543.3 metres, the Kalilager was intersected in the shaft, showing a Mächtigkeit of 20 metres with an Einfallen of 6 degrees; samples yielded a K₂O content of 12.2 per cent. A Füllort was prepared at 561 metres. Streckenauffahrung commenced in 1912 and Abbau in 1913. Surface installations comprised a Kauen- und Bürogebäude, Werkstattgebäude, Kesselhaus with 12 steam boilers and a 60-metre chimney, Brunnenanlagen, and a Fördermaschine rated for 120 tonnes per hour. The Gewerkschaft Ilberstedt and the neighbouring Gewerkschaft Anhalt shared a joint processing factory for 10,000 Zentner (dz) daily Rohsalzverarbeitung with a Verlademagazin and Mühlenanlage. A Werksbahn connection ran to the station at Ilberstedt.
The Kalisyndikat had permitted extraction from the Werk Ilberstedt from 1 August 1913. The Gewerkschaft was assigned a Beteiligungsziffer of 80 per cent of the average Beteiligung of all works in 1925 — a reflection of the diminished standing of smaller independent operations after the rationalisation wave. In December 1925 the Gewerkenversammlung voted to voluntarily place the mine into Stilllegung until the year 1953, in the context of the wider Kali crisis following the First World War. This effectively ended mining. In June 1927 the Gewerkenversammlung resolved the Liquidation and Gesamtveräußerung of the Gewerkschaft to the Kali-Industrie AG, with Kali-Industrie shares offered to Gewerken at a rate of 600 Reichsmark nominal per Kux; the transaction took effect from 29 August 1928. Following the Betriebsstilllegung, the surface plant was demolished.
For approximately sixty years the shaft remained abandoned and sealed underground. In the intervening decades the underground workings of the Steinsalzbergwerk Bernburg–Gröna advanced north-westward, eventually extending beneath the territory of Ilberstedt. In 1982, recognising that the underground advance had brought the main mine's workings close to the old Schacht Johanne, the shaft was reaktiviert as an einziehender Wetterschacht to supply Frischwetter to the north-western section of the Grube Bernburg–Gröna. The reopening in 1982 came exactly sixty years after the voluntary Stilllegung of 1925. The shaft today operates under the designation Schacht Johanne, and its headframe — visible alongside the railway line at Ilberstedt — is associated with ongoing periodic salt extraction-related Bergschäden in the community of Ilberstedt, which the operating company (formerly Esco, now K+S Minerals and Agriculture GmbH, a subsidiary of K+S AG) has compensated. The Steinsalzbergwerk Bernburg with its principal Schacht Bernburg and Schacht Gröna surface complex remains an active production site extracting Steinsalz from the 115-metre-thick Leinesteinsalz at depths of approximately 500 metres.