Russian potash industry: Issues of rational and safe mining

Abstract

The Russian Federation controls almost a quarter of potash fertilizer world market. Natural potassium salts serve as the main source for the fertilizer production. Mineral and raw materials base considers nine potash deposits to be on the state balance. However, potash mining in production quantities is currently executed only at the Perm region Verchnekamskoe deposit by four mines of the Uralkali Company and by the Usolskiy mine of EuroChem. During 2020 almost 52 million t were mined, which allowed to produce more than 14 million t of potash fertilizer. The main feature of salt deposit development is the necessity to protect the mines from fresh and brackish waters breakthrough. Experience of developing potash deposit throughout the world helped to formulate basic principles of mining operations. Protection of mine openings from underground and surface waters, that are corrosive to the rock salts, is secured by formation of a waterproof rock stratum, referred to as the waterproof pillar in mining practice, between the top of the upper mined layer and the bottom of the lowest aquifer. Usually, it is achieved through application of the room-and-pillar mining system that has to maintain the integrity of the waterproof pillar during the mine life until its liquidation and completion of the undermined rock mass deformation process. Despite the applied security measures, a significant number of mines were lost as a result of hazardous flooding. Three large-scale accidents took place at the Verchnekamskoe deposit. Mining and geological conditions that accompanied those hazardous situations are examined, and analysis of probable causes of water breakthrough into mine openings is carried out. Based on summarizing the experience of Verchnekamskoe potash deposit development it is demonstrated that the main factor that determines the efficiency of rock salt mining is provision of mining security and protection of mines from flooding. At the same time the approach to minimization of anthropogenic hazards should be based on applying justified engineering regulations at the mine planning stage and on the up-to-date information-based scientific support of the mining process, based on permanently functioning system of complex monitoring of the rock mass state.