Earth

Subsoil

Mineral deposits

Extraction activity in recent times

At the end of the 9th century the helicoidal-wire technique developed. A motor-driven thread goes through the cutting area. The thread, during functioning, is constantly cooled down by the water: in this way it is possible to extract big blocks. At the moment there are many mechanical tools to be used for extractions: the most popular tool is the diamond-thread cutter. A steel cable, of 6 mm diameter, on which small diamond cylinders are inserted, slides on the rock. This technique is twenty times faster than the helicoidal wire. Another innovative technology that is used for extractions in caves is called “water-jet”: it consists of excavating with a high pressure water-jet, which is able to break the rock. Once it is extracted, the material is transformed (it is cut into blocks or sheets and its surface is treated) and used for different applications.