The Herdorf miner Wilhelm Fetthauer opened up in 1931
the pit "Red Zeche".
"Bollnbach" had long since been shut down. Due to the rapid overexploitation in
at depth, some veins remained undeveloped at the top.
Fetthauer drove a tunnel 60 m into the mountain and was lucky.
He encountered a 2 to 3 meter high corridor, the brown iron stone
contained a good 40% iron and had a high manganese content. But
rising water led to closure in 1936.