Data on the processes of mineral redistribution in the Kuchuk lake salt deposit are presented, and the difficulties arising in this regard during the mineral reserve accounting and write-off are discussed. Lake salt deposits are quite unusual objects with individual specifics. A unique technology using a geotechnological method for the sodium sulfate extraction with minimal environment impact has been developed for the Kuchuk deposit. This method allows one to change the volume of extraction of the main mineral without a damage for the deposit and the environment.