The bulkhead, which links the Solikamsk-1 and Solikamsk-2 mines, is a 65-metre long waterproofing structure made up of seven segments.
The structure was designed with materials that can withstand brine pressures at the Verkhnekamskoe potash deposit, said the company, with sensors also installed to constantly monitor these parameters.
All materials underwent pilot tests taking into account the rock mass, depth of excavation, and physical and mechanical characteristics of the relevant mine brines.
"The bulkhead was designed and built to withstand the maximum possible design pressure from the brines," said Eduard Smirnov, Uralkali subsoil management director. "This is particularly significant because Solikamsk-1 is Russia's only source of carnallite, a raw material crucial to Russia's titanium and magnesium industry."
Uralkali was forced in 2006 to close the Berezniki-1 mine, which is also linked to the Verkhnekamskoe potash deposit, after it was flooded with brine inflow.
The first two bulkheads at Solikamsk-1 and Solikamsk-2 fields were waterproofed in the 1980s. The company strengthened the waterproofing structure further in 2014, with the working area on the side of Solikamsk-2 mine grouted with a special waterproofing mix.