At domestic brine fields deposits of rock salt of various thickness (from 40 to 700 m) and depth (from 300 to 1400 m) are developed by underground dissolution, through wells. As a rule, cylindrical chambers of 100 m diameter are used. The chambers are arranged on a 200x200 m grid, and the width of inter-chamber pillars is 100 m. Such sizes of pillars are insufficiently justified due to limited experience of underground dissolution and lack of tested solutions. As a result, there is a danger of pillars destruction and surface shifts.

At the Yar-Bishkadak field the rock salt deposit with the thickness of 200-700 m and the thickness of covering rocks of 500-600 m is developed by underground dissolution through wells from the surface. The development is carried out by individual vertical chambers, the diameter of which, according to the project, is equal to 100 meters. Due to untimely control of erosion results, there are deviations from the project, sometimes the diameters of the chambers reach 160-190 m, so it is not clear how much the actual outcrops of excavations meet the requirements of stability. The current absence of surface shifts and large outcrops in the chambers associated with the cessation of operation of wells is not yet a sufficient guarantee of the safety of further development, as the duration of operation of the chambers (3-15 years) is short compared to their total service life (50-80 years). As a result, there is a need to predict the stability of rocks and determine the maximum allowable spans of brine excavations.

Development of rock salt deposits by underground dissolution, as a rule, is carried out by cylindrical chambers arranged on a given (square or rhombic) grid. The calculation of parameters of stable chambers and separating pillars can be approached by the method of continuum mechanics, using, for example, the solutions obtained for vertical mine shafts. However, the continuum mechanics solutions are developed only for single excavations, and their application to the calculation of cylindrical chambers located on a given grid and having a mutual influence makes it necessary to introduce additional conditions.

The Yar-Bishkadak field, which supplies brine to a number of chemical enterprises in Bashkiria, develops a section of salt deposit with a thickness of 200-700 m, with the thickness of overlying rocks being 400-500 meters. Development is carried out by isolated chambers, which are created by salt leaching through wells drilled from the surface. The adopted technology - step leaching - provides creation of chambers of approximately cylindrical shape with a diameter of 80-100 m and height by the end of mining equal to the thickness of the salt deposit (the height of individual chambers currently reaches 100-150 m) ....