At present, the development of minerals is carried out and designed at great depths. Practice shows that at depths of about 800 m the stability of mine workings significantly deteriorates. To predict their stability, it is necessary to comprehensively investigate the physical and mechanical properties of rocks, especially rheological properties, such as stress relaxation.

Physical and mechanical properties of salt rocks were investigated in laboratory and mine conditions in relation to the problems of rock mechanics-calculation of rational parameters of the chamber system of development and identification of regularities of manifestations of rock pressure. These tasks are of great importance in the development of Starobinsky potassium salt deposit, represented by several potassium beds, occurring at a depth of 420-640 meters from the surface. Two potash beds with thicknesses of 1.8-4.0 m and 4.5-7.0 m, occurring respectively at a depth of 420 and 580 m, are being developed at the deposit.