Felsstollen

Felsstollen is a term used in mining and civil engineering to describe a type of tunnel or gallery excavated through solid rock. The term is of German origin, with "Fels" meaning rock and "Stollen" meaning tunnel or gallery. These tunnels are typically constructed using drilling and blasting techniques, or more modern methods like tunnel boring machines.

The primary purpose of a Felsstollen can vary widely. In mining, they are often used as access tunnels to reach ore bodies, ventilation shafts, or drainage galleries to remove groundwater from the mine. In civil engineering, Felsstollen are essential for transportation infrastructure, such as railway tunnels or road tunnels, that need to pass through mountainous or geologically stable rock formations. They can also be used for water conveyance, such as aqueducts or penstocks for hydroelectric power plants.

The excavation of a Felsstollen requires careful geological assessment to understand the rock mass properties, stability, and potential for water ingress. Support systems, such as rock bolts, shotcrete, or steel arches, are often installed to ensure the long-term stability of the tunnel. The design and construction of Felsstollen are complex engineering challenges that demand specialized knowledge and equipment. The term implies a direct excavation through the rock rather than tunneling through softer ground or using cut-and-cover methods.