Is that orange color in the water natural? It is not. That ochre color is a telltale sign of what flows from the Franziska Erbstollen. This is a significant historical drainage tunnel in Witten.
The Franziska Erbstollen has a story that stretches back centuries. Mining is a huge part of this region’s history. The Erbstollen Franziska played a vital role in the Ruhr region’s mining operations.
Let’s step back in time. It is the late 18th century. The industrial revolution is beginning to transform Europe. In 1772, the Erbstollen Franziska was first granted its mining rights. This was updated in 1783 and again in 1823. Johann Peter Mercklinghaus and J.C. Bröcking requested permission to advance a deeper drainage tunnel. They acted on behalf of Freiherr von Schirp. This new tunnel would replace the old one.
Imagine the scene. Workers labored tirelessly to dig the Franziska Erbstollen. They used picks and shovels to create this vital drainage system. The Franziska Erbstollen would eventually stretch over 4,000 meters.
The Franziska Erbstollen was essential for draining several mines. These included Franziska, Verlorene Posten, Portbank, Stuchtey, Franziska Fortsetzung, Hamburg and Augustus. Think of the Franziska Erbstollen as the region’s primary drainage vein. It kept the mines workable by removing groundwater.
In 1839, the Franziska Erbstollen was consolidated. It joined all the mines on Helenenberg to form Zeche Ver. Franziska Tiefbau. This merger streamlined operations. It also highlighted the Franziska Erbstollen’s central role.
However, mining operations changed over time. In 1925, the Franziska Erbstollen ceased its coal extraction activities. Yet, its function as a drainage tunnel continued.
Even today, the Franziska Erbstollen still drains mine water. As you can see, the water flowing from the tunnel is a distinctive orange-brown. This color comes from the oxidation of iron. Iron(III) oxide hydrate precipitates out. This is commonly known as iron ochre. This natural process paints the streambed in vibrant rusty hues.
The Franziska Erbstollen’s mouth is still here. Although it is not accessible to the public, you can see the water flowing from the tunnel into the Mühlengraben. This then flows into the Ruhr.
So, the next time you see the unusual coloring in the water, remember the Franziska Erbstollen. It is a testament to the region’s rich mining history. It shows the ingenuity and hard work of the miners who shaped this landscape. It reminds us of the ongoing impact of industry on the environment.