The Starobin deposit of the potash salts is one of world's biggest deposits and concerning the size it is the second on the CIS territory. It was formed some 300 million years ago at the end of the Devonian age of the geological history.

   In place of the present Polessye there was a shallow sea with the ample lagoons. As a result of active evaporations and downfolds of the basin bed owing to the vertical vibratory movements the sediments of potash and sodium salts were formed which were stratified with clay and carbonate layers.

   The riches of the Starobin deposit are repre-sented by the sylvinite (potash salt), camalite (magnesium salt) and rock (edible) salt.

   The potash salts are located inside of the rock salt layers. Several dozens of the potash levels are found at the deposit. The commercial inte-rest is presented by the four levels which are the most sized concerning the area and thickness. The tectonics of the deposit conditioned the occurrence of potash levels at the different depths. The commercial levels occur at the depths from 400 till 1200 meters and more. Their thickness varies from 4 till 20 meters.