In the millions of years after the formation of the Cretaceous, there have been changes to the earth's surface (e.g. earth crust shifts or uplift). The water of the primordial sea has evaporated or run away. Land has been created by drifts, flooding, etc. Much later, the glaciers of the ice ages pushed further layers of earth over the chalk and changed the surfaces. Various top layers lie over the chalk today.
Under the load of the chalk and later sediment deposits, the mighty salt layers lying under the chalk were uplifted in some places. This also raised the chalk itself, so that it can now be found near the surface in some places. This happened in geological periods.
In the Lägerdorf area, the overburden layer above the chalk is three to ten meters. The mineable area is approximately ten square kilometers (an area of 3.2 x 3.2 kilometers). In other areas of our district and northern Germany, the chalk lies at very different depths: Krempe 40 m, Heide 100 m, Büttel 350 m and near Hamburg even 800 meters below the surface.
The graphic below shows the chalk pits of Lägerdorf. The so-called "English pit" also called "Old pit Alsen" - was 58 meters deep. The Schinkel pit of the Breitenburger factory of the Alsen factory was mined to a depth of 120 meters.
The Saturn pit is 60 meters deep. Chalk mining has been suspended here since 2000. In 2000, the Heidestrasse pit expansion area was opened up and is currently being mined. The chalk is mined here with bucket wheel excavators, processed into sludge and pumped into the cement works via a pipeline.
With current consumption, the reserves for cement production will last until 2080. From around 2035, the mining area will have to be relocated to the east of Lägerdorf, to Moorwiese/Moorstücken. In the Schinkel/Heidestraße area, the water pumps will then be shut off, so that a 170-hectare "chalk lake" will form.
Translated by Google •
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