| | |
| 1563 | slate from Raumland first mentioned. |
| 1850 | start of underground mining. |
| 1860 | a ministerial order prohibits straw roofs. |
| 1860 | Grube "Delle" opened. |
| 1923 | Grube "Delle" closed. |
| 1980 | documentary "Schiefer in und um Raumland". |
| 1983 | show mine opened to the public. |
The slate was formed about 350 to 400 Million years ago during the Middle Devon.
It is a sedimentary rock, composed mainly of clay, which was deposited slowly on
the floor of a calm sea.
Transported deeper and deeper by subsidence, under pressure and high temperature
the clay was tranformed into rock.
Slate is easy to split, which allows to produce thin plates, which are good to
cover roofs.
This slate is sedimentary, but it does not split along sedimantary layers.
The rock was folded during the variszian orogeny, which created the Rheinisches
Schiefergebirge (Rheinian Slate Mountains).
The stress of the rock created a secondary weakness, which is used to produce
the thin plates.
For more than 400 years slate was mined in small village Raumland.
At the heyday of slate mining, 450 men were working in 12 pits.
The slate was sold all over Germany, and even abroad.
One of the slate mines, called Grube "Delle" is now restored and open to
the public.
It shows the underground mining, the tools, and the technology.
Slate was quarried since the 16th century in open pits.
Much later, around 1850, underground mining started.
At first only slate for local needs was produced.
Many roofs were still made of straw, which was less durable but much cheaper.
But in 1850 a ministerial order prohibited straw, probably because of the danger
of fire.
Subsequent the slate mining boomed, and the heyday of mining with 450 miners
working here, began.
Slate Mine
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