The Deep Tunnel () is an adit at Hercherhof near Freiburg, Germany. It is a part of the Schauinsland mine complex and was built for the Stolberg Zink AG to provide easier access to the seventh floor level of the Roggenbergschacht mine. Construction began in 1938. It was termed part of the Four Year Plan, an economic plan designed to prepare Nazi Germany for war, and Hermann Göring's name was invoked in a dispute between the mining company and the state environmental protection agency when the agency requested the greening of excavated material.