The sinkhole - which is 5 metres in diameter - was discovered during monitoring of the zone of transitional period panels, the hazardous area of the minefield of the flooded Berezniki-1 mine.
The hazardous area of the transitional period panels has been fenced off and access has been restricted since 2013.
The zone of transitional period panels is an area in the town of Berezniki measuring 800 by 800 metres, surrounded by Reshetov square, Kotovsky street, and Gastello street. In 1944-46 and 1963-64, carnallite B seam was mined in the transitional period zone; in 1948-54, sylvynite AB seam was mined there.
Continued comprehensive monitoring of the area has been in place since 2006. Based on analysis of the monitoring data, Galurgiya predicted in 2013 that soil subsidence might occur in this area in 2015. In 2013, representatives of Galurgiya and the Mining Institute of the Urals Branch of the Russian Academy of Science determined the boundaries of this hazardous zone. In May 2014, the boundaries were confirmed by Rostechnadzor. Uralkali says the soil subsidence will not affect the current activity of the industrial facilities or social infrastructure in Berezniki.