Institute of Mining and Chemical Industry

Abstract

Introduction. There are the speleological and engineering-geological areas in karst studies. Engineeringgeological area has two aspects, the surface aspect including the construction of surface buildings in the areas with the karst hazard and the subsurface aspect of prevention and protection from karstification when developing mineral deposits. Although shafts in salt mines has been working since the Middle Ages, the salt karst is still the reason for the destruction of a lot of salt mines. Research aim is to reveal the physical and chemical mechanism of salt karst development and the reasons for accidents and flooding in salt mines. Methodology included the analysis of regular survey measurements of surface deformation, recording of brine manifestations in mine workings, chemical analyses in brines, hydraulic measurements at surface watercourses, direct determinations of brine aggression, geophysical research by the natural field method, vertical electrical sounding, etc. In recent years, in order to control surface deformation, the data from the radar survey have been used. Results. A clue to the mechanism of salt karst responsible for accidents is the theory of hydrodynamic systems by A. M. Ovchinnikov, the elements of which are the areas of accumulation, transit, and discharge. Brine motion is in the supra-salt reservoir. The trajectory of brine motion is determined by the relief of the salt table. Pressure flow take up the elevated terrain. Accumulation areas are confined to stream corridors permeating the low-permeability strata which covers the salt. The area of transit distinguishes between the zone of the pressure flow and the vertical slot where the brines move in the gravity turbulent conditions. Mine workings make up the discharge area. Within them under the action of aggressive brines triangular niches develop. Pillars undercut results in their collapse and surface sink. Summary. Salt karst development mechanism disclosure has made it possible to propose the methods for predicting its effect and the ways of predicting flooding in salt mines.