The depth of the deepest of the borehole in the world for more than 12 km

Kola ultradeep well located in the Murmansk region. It was founded in 1970, in honor of the 100th anniversary of the birth of Lenin. Unlike other wells, drilling was carried out not for the sake of oil production or exploration, and of scientific interest: the study of the composition of the lithosphere.

24 May 1970 drilling rig Uralmash-4E series began its work. To the dismay of some geologists throughout the drilling they met only the granite layer, although it is anticipated that there will be found a clear boundary between granite and basalt layers. Total allocated 12 types of granite rocks, changing their physical properties as we move deeper into the Earth.

By 1990, the drilling had to complete a number of reasons, one of which was to raise the temperature to 220 degrees Celsius, which greatly hampered the work. In recent years, the fate of the project was discussed for a long time, but by 2008, the well was finally abandoned, and the equipment dismantled.

via factroom.ru