Eisensteinschacht

Hoisting shaft and pit house Albertsgrube

In the two groves in the background, the remains of the former iron ore shaft and its associated pit house can be found. The shaft/system complex consisted of the iron ore shaft, a ventilation shaft, and a 60 m and 90 m level, following two fissures/faults that are still visible in the meadow (despite the fill in 2019).

The Albertsgrube was licensed for zinc, lead, and iron. Although the focus was on the extraction of zinc and lead, the primary mineral extracted from the iron ore shaft was mostly limonite (2Fe2O3·3H2O), also called “iron ore.” The main extraction at the iron ore shaft took place between 1853 and 1859 when the Albertsgrube was leased to the smelting company “Concordia” in Eschweiler-Pumpe. This was the only period during which the Albertsgrube was registered as an iron mine instead of a zinc/lead mine. Although the iron ore shaft is not connected to the other tunnels of the Albertsgrube, the diverted surface water continues to drain through the buried ventilation shaft.

Main ores extracted from Albertsgrube:

Galena (Lead sulfide/PbS/Galena): Galena has a content of 86.6% lead and includes sulfur, along with silver in the Stolberg area, ranging from 100 g to 1300 g per ton.

Sphalerite (Zinc sulfide/ZnS/Sphalerite): Source ore for zinc extraction. The term "Blende" derives from the fact that the weight and metallic luster of this ore suggest it contains metal, but until the end of the 18th century, no metal could be smelted from it due to the low boiling point of zinc.

Pyrite (Iron sulfide/FeS2/Pyrite and Marcasite): More of a byproduct of mining, it was partially used for sulfuric acid production.

Cannel coal: Paragenesis of the three aforementioned sulfide ores. Cannel coal represents the typical primary ore of the Stolberg deposits but had to be laboriously processed (separated).

Iron ore (Iron hydroxide/2Fe2O3·3H2O/Limonite): The limonite extracted here was formed as secondary ore in the oxidation zone (thus above the groundwater level) through weathering of pyrite.

In everyday life, we encounter limonite mainly as rust. Ochre is nothing more than the powdery weathering form. Limonite was the most important iron ore for the local iron industry and currently ranks worldwide after magnetite and hematite. Although iron ore played a lesser role in iron production in antiquity, it was already mined and smelted by the Celts in our area, as indicated by finds at the Korkus (also referred to as “Im Kakus,” a forest area near Hastenrath, about 4 km away).

(Text: Jens Mieckley)