Schieferbergwerk Lehesten Lehesten · Thüringen · Germany

Slate had been extracted from the Lehesten area since at least the thirteenth century, beginning with small surface quarries (Brüche) on the Thurinian slate ridge. By the mid-nineteenth century, two major working sites had developed: the Staatsbruch and the adjacent Oertelsbruch, the latter operated as a private enterprise by Karl Oertel. Together they comprised one of the largest slate open-cast workings on the continent, with the Staatsbruch alone measuring approximately 800 metres in strike length, 300 metres in width, and up to 80 metres in depth.

The Herzögliche Schieferbrüche Lehesten were established formally around 1845, with construction of the Göpelschachtanlage (horse-gin shaft installation) at the Kießlich quarry face around 1850. The Göpelschacht was designed with winding cages to hoist the mined slate in wagons (Hunte) from the quarry floor. Initially two horses drove the gin on its circular track. In 1865 the horse-gin was replaced by a steam hoisting engine supplied by the Firma Earnshaw of Nuremberg, installed in the Göpelhaus on the former horse-track; a slate-masonry chimney for the steam boiler was erected alongside. In 1908–09 a works electricity generating station was brought into service and in 1909 the steam engine was converted to direct-current electric drive. From 1921, power was supplied from the Überlandnetz (regional grid), built by the industrialist Franz Itting of Probstzella. A drainage adit (Lösestollen) was driven at approximately 30 metres depth to drain the workings naturally into the Loquitz valley.

In 1857, the Herzögliche Schieferbrüche already employed 203 workers recruited from upper Franconia, alongside 79 local workers. By 1877 the workforce had grown to 586. With the strong competition of Karl Oertel's adjacent Oertelsbruch, the combined workforce in the Lehesten quarries reached almost 2,000. In 1858 the railway between Ludwigsstadt in Franconia and Lehesten was inaugurated — partly through the financial support of Karl Oertel, who contributed 300,000 Goldmark to its construction — and the Staatsbruch and Oertelsbruch each received their own rail connection, substantially increasing their commercial reach. Around 1900, however, demand for roofing and wall slate fell by approximately 25 per cent, affecting profitability. The Doppelspalthütte (double-splitting hut), where quarried slate was cleaved and trimmed by hand, was built in 1898 on the site where it still stands.

In 1920 the Herzögliche Schieferbrüche passed from ducal to Land Thüringen ownership and was thereafter known as the Staatsbruch. The workforce reached approximately 2,000 during the boom years; a prolonged strike of slate miners in 1928 entered the regional history of the labour movement. The years of economic crisis up to 1939 brought repeated fluctuations in output.

During the Second World War, the NS regime planned to use the underground workings of the Staatsbruch and the Oertelsbruch for armaments production. In the Oertelsbruch, a test stand for V2 rocket engines was established and KZ inmates from an outer camp of KZ Buchenwald — KZ-Außenlager Laura at Schmiedebach — were deployed as forced labour. In the Staatsbruch, a plan to install Schott Jena armoured-glass production did not materialise. In April 1945 the camp was evacuated and approximately 600 prisoners were driven to Bahnhof Wurzbach for transport to KZ Dachau.

After 1945, both slate works passed into Volkseigentum in 1946–1948. From 1952 they were operated as the VEB Schiefergruben Lehesten. In 1964, consolidation with other Thuringian slate workings produced the Vereinigte Thüringische Schiefergruben Unterloquitz (VTS), headquartered in Unterloquitz. The relocation of the consolidated entity to Unterloquitz was in part driven by the fact that Lehesten, following the closure of the inner-German border in 1961, had become part of the strictly controlled Grenzsperrgebiet: entry required application and approval from the Volkspolizeikreisamt. From 1975, all slate extraction at Lehesten moved exclusively underground. The surface open-cast operations at the Staatsbruch ceased in 1964, and extraction continued underground until the final closure of the Lehesten workings. After closure, the former Tagebau gradually filled with groundwater, forming the Schiefersee — now over 40 metres deep — while the underground workings flooded progressively.

Following the political changes of 1990, the key production buildings of the Staatsbruch were transferred to the Stiftung Thüringischer Schieferpark Lehesten. After extensive reconstruction of the historic buildings, the Technisches Denkmal „Historischer Schieferbergbau Lehesten" opened in 1993. The industrial ensemble, including the Göpelschachtanlage — unique in Europe — received Denkmalstatus in 1999. The Staatsbruch site was designated a Naturschutzgebiet (nature reserve) from 2001 and has since been recorded as a habitat for over 170 Red List species including the eagle owl. In 2006, the Schiefersee geotop received the designation Nationaler Geotop. The approximately 105-hectare Schieferpark Lehesten hosts a conference and seminar centre, walking routes and two Geopfade (4 km and 800 m), a model village illustrating the craft of slate roofing (Modelldorf), and the surviving Schacht IV installation of 1961, the latter still in museum development. Guided tours operate through the Göpelschachtanlage and the Doppelspalthütte, with the historic hoisting machine demonstrated in working order. The site is part of the Thüringisch-Fränkische Schieferstraße.