Lothar healer slate

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Lotharheil slate works

The Lotharheiler slate is mined in the area of ​​the municipality of Geroldsgrün in Upper Franconia . It is one of the few quarries that are operated underground in Germany . The rock originated in the Lower Carboniferous .

Dismantling

Lothar healer slate is the only operating ski slate won -Steinbruch in Bavaria. There, the slate was in before about 300 years opencast promoted. In 1857, the low tunnel , which is 500 m long and only 1.70 m high today, was first mined . The rock is mined by igniting black powder , which is brought into drill holes made with drilling equipment on the mining floor. The transportation of the crushed rock is carried out with one of the last field paths in Bavaria with the track width 600 mm, by a electric locomotive of Schuckertwerke Siemens is pulled with the operating voltage of 36 volts.

There is already a new, larger tunnel that a truck can drive through.

  • Old tunnel in Lotharheil with mine locomotive

  • New tunnel

history

Alexander von Humboldt is said to have recognized the quality of this slate as early as 1792/1793 when he was working as a mining assessor in the area. The mining rights granted to 45 hectares of the underground deposit are said to go back to King Ludwig II .

The right to dismantle was acquired in 1857 by Reichsrat Lothar Freiherr von Faber , who expanded his pencil factory in Nuremberg, which had existed for 100 years at the time, into an industrial operation (today Faber-Castell ). The name of the slate goes back to his first name. Faber needed the slate for the production of slates in the company he founded in Geroldsgrün. Since the extracted slate was too hard for this, Faber sold the mine in 1895. In 1904 it was acquired by the slateer Christian Teichmann; it is still owned by his descendants.

At the end of the 1960s, the company's own production of roof and wall slate was given up for economic reasons and outsourced to other companies. These slate products are still available today. The company manufactures products under the name Lotharheiler slate for gardening and landscaping , living areas , as gravestones and as jewelry .

geology

This slate deposit is part of the Thuringian Slate Mountains , which geographically extend over the southeastern Thuringian Forest and northwestern Franconian Forest . The Lotharheiler slate was formed in the Lower Carboniferous between 330 and 360 million years ago when a sea covered the area of ​​what is now the Franconian Forest. Far from the coast, fine-grained quartz sand and clay were deposited at great depths . Mountain formation began in the Upper Carboniferous 300 to 330 million years ago and the resulting heat and pressure turned the deposited clay into a shale clay and finally a layer of clay slate with a thickness of 14 to 20 meters. The rock layer was folded and tilted when it was created.

Rock description and mineral inventory

The dark gray- blue slate consists of a special muscovite , sericite (a finely flaked muscovite), chlorite , albite and a high proportion of quartz . These minerals and the carbonaceous components that occur in this rock in varying proportions determine its color.

Due to its high proportion of quartz, this natural stone is wear-resistant. Furthermore, it is characterized by a high density with a low water absorption. The slate is frost, color, acid, alkali and heat resistant up to 300 ° C. Due to the parallel alignment and the flat clay minerals, it is easy to split.

Individual evidence

  1. ↑ a b frankenpost.de Werner Rost: Diamonds cut the "blue gold" , May 17, 2011, accessed on September 12
  2. ↑ frankenpost.de : Elfriede Schneider: By King Ludwig's grace. Lotharheil is the only slate factory in Bavaria. In its mining rights, it can refer to the fairy tale king , from May 17, 2011, accessed on September 15, 2012.
  3. ↑ schieferladen.de : Slate products on "Der Schieferladen" , accessed on September 15, 2012
  4. ↑ schieferlexikon.de : The slate deposits of Thuringia , accessed on September 11, 2012
  5. ^ A b Siegfried Siegesmund, Karl-Jochen Stein: 150 years of slate from Lotharheil . In: Naturstein : Hf. 12/2007, p. 61 ff. ( Available online ; PDF; 360 kB)

Web links

Commons : Lotharheil (Geroldsgrün)  - Collection of images, videos and audio files

Coordinates: 50 ° 20 ′ 41.1 ″  N , 11 ° 32 ′ 50.7 ″  E