The dynamics of mass decrease of large dolomite particles of various weathering degree has been studied in a laboratory experiment. In the process of long-term composting of large dolomite particles with acidic sod-podzolic sandy loam soil it was shown that the decrease in the mass of dolomite granules depended on the composting time and the period of storage in dumps. The research results have shown that for 61 day of composting there were no clear patterns indicating the influence of the dump storage period on the speed of the material dissolution in the soil. It was found that after 61 day of dolomite composting in the soil, the loss of particle mass ranged from 4.1 to 8.2% of the original. After 114 days of composting, the mass loss of dolomite particles, that were stored in dumps for a long time, ranged from 32.8 to 34.2%. When dolomite particles were stored in dumps for a shorter period of time, the mass loss ranged from 8.7 to 14.5% of the initial mass. The paper considers the mechanisms of weathering