ABSTRACT
The research object is the Upper Kama potash salt deposit. It is one of the biggest potash and magnesium salt deposits in the world. Two contiguous sylvinite layers are being developed at the depth of 250–400 m. The mining structure is characterized by a great water content of the overlying terrigenous and carbonate rocks which may result in a flooding of the mined-out area. The impermeable rib pillar which separates the industrial strata from the water-bearing layers provides safe mining conditions. The decrease of the deformation value of the impermeable strata and preservation of its water-resisting properties is ensured by the use of the room and pillar method with a rigid rib pillar. Comparative studies have been carried out to establish the relation between the deformations of the room and pillar elements and earth surface subsidence. The earth surface subsidence was determined using the geodetic measurements according to the ground reference points. The vertical and transverse deformations of the pillars, the stratification of the parting and the roof of the top layer were measured by the experimental stations using the tape extensometer along the contour and depth reference marks. The research results which had been carried out in various mining and geological conditions made it possible to establish a relation between the processes of the ribs’ deformations, their loading rates and ground subsidence. Based on the results of the experimental work, the theoretical description of the chamber deformation processes using the mathematical modeling methods was made.
