More Info wonderfulengineering.com
Berezniki is a Russian city located in the Ural Mountains. It is slowly finding its way into the soil. However, a more realistic characterization would be that it is slowly sinking into the soil. The city held 150,000 persons and was created on top of a potash mine. This was normal procedure throughout Soviet times. However, after nearly a hundred years of extraction, vast holes have been left under the city. The ceilings of the vast tunnels under Berezniki are supported only by walls and pillars of soluble salt. Back in 2006, a freshwater spring started pouring into the mine roughly 720-1,500 ft under the surface, and you can imagine what occurred; the salt dissolved, thereby taking away the support under the city of Berezniki.
A substantial section of the residential neighborhoods and enterprises of Berezniki has been damaged by sinkholes. These sinkholes are huge in number with the biggest one of them titled ‘The Grandfather’. The Grandfather is around four hundred meters broad and has a depth of about two hundred meters. It also presents a threat to the lone rail route that travels into and out of the potash mines. Berezniki is responsible for generating ten percent of the world’s potash, and the mines are the major employment of the city. The closure of the mines will have a severe effect on the local economy.
A variety of high-tech devices including seismic sensors, video surveillance systems, periodical surveys, and even satellite monitoring systems are in place for tracking the changes in height of roofs, roadways, and walkways in Berezniki for anticipating the creation of sinkholes. However, engineers have confirmed that the age of sinkhole development is ended since much of the mine is flooded already. Nonetheless, government officials and corporate executives are arguing if they should transfer the full city to Kama River’s opposite side where the bedrock is solid.