Behaviour of Rooms and Pillars in Deep Potash Mines

CIM Bulletin, 1973

DENNIS Z. F. MRAZ, Engineering Manager, International Minerals & Chemical Corporation (Canada) Ltd., Esterhazy, Saskatchewan

Because rock salt and pot ash formations contain particles capable of elastic deformation, the material has usually been compared with various rheological models containing elastic elements. Extensive laboratory testing of salt and potash samples resulted in various theoretical conclusions based on conditions quite different from those in a deep mine. It is felt that sufficient data have now been collected from underground measurements and observations to demonstrate the inelastic behaviour of salt masses in a deep mine. The conditions in deep salt strata can be defined as near hydrostatic, because the acting pressures are very high compared to the negligible elastic limit of the salt. The pressure field and creep around the single opening is a function of its shape, size and age. The same factors, together with extraction, determine the behaviour of the mining area. The application of the correct analytical method in mine design can significantly improve t he excavation techniques and predetermine t he long-term behaviour of openings.
Keywords: Czechoslovakia, Esterhazy, Saskatchewan, potash, rock mechanics, virgin ground, excavation, Load, mining, pillar, Pillars, Pressure, rock mechanics, Salt, Salts