Berezniki is a city on the Kama in the Perm region in Russia, west of the Ural Mountains. In addition to oil and gas wells, underground mining of potash salts is of economic importance. But the mines have devastating effects as parts of the site and the surrounding area are affected by subsidence. To make matters worse, an accident in the pit BKRU-1 is added, which extends under the urban development. As a result of this accident it comes since then to the flooding of the mine systems, which means for large areas the risk of great dolinas. A huge earth fall, for example interrupted the railway line in 2010. The break-in has been widening since then. Also in the surrounding area houses disappeared in the sinkholes.