This paper reports the results of the study of a huge collapse that occurred in June 1986 within the area of the 3rd Berezniki potash mine (the Verkhnekamsky potash deposit, Ural). Processes that took place between the first appearance of a water inflow through the mine roof and the eventual collapse are reconstructed in detail. The origin and development of a cavity that induced the collapse are revealed. Two factors played a major role in the formation of the collapse: the presence of a tectonic fold/rupture zone with in both the salt sequence and the overburden (the zone of crush and enhanced permeability), and the ductile pillars mining system.
Collapse above the world's largest potash mine (Ural, Russia).
International Journal of Speleology,
Available at: http://scholarcommons.usf.edu/ijs/vol31/iss1/8