The Rothschönberg tunnel is the deepest and longest water release tunnel in the Freiberg mining area and is part of the Krušnohoří Ore Mountains UNESCO World Heritage Site. It was built in 1844-1877. The fiscal (state-financed) part has a length of 13.7 km from the Röschenmundloch in the Triebisch near Rothschönberg to the VIII. Lichtloch in Halsbrücke and an increase of 0.032%. For this purpose, 8 light holes were sunk and the adit was excavated in on-site operation with a width of 2.5 m and a height of 3 m. In the mining area to Langenau (Frankenschacht) there are still a good 15 km of main adits (including Reiche Zeche, Drei-Brüder-Schacht), with side adits to Zug and Großschirma it should be around 50 km.
The 8 light holes, Stollntor and Röschenmundloch can be experienced on the bike tour (Tour d'Lichtloch).
The Röschenmundloch was driven down from the Stollntor over a length of 847 m in solid rock or as a sandstone vault with a width of 2.5 m and a height of 2 m between 1844 and 1858. For flood protection reasons, it is 1 m above the Triebisch. The mean discharge is currently 0.65 m3/s.