The present invention pertains to a mineral exploitation method and, more specifically, to a method for extracting potassium salts from underground deposits. In the method according to the present invention, an intermediary stage is carried out between the primary mining and secondary mining stages, and in this intermediary stage sinks (8) are created that receive the water-immiscible fluid (9) used in the primary mining stage, exposing an amount of potassium chloride remaining on the cavern ceiling, at the end of the primary mining stage, which will be dissolved by a second solvent during the secondary mining stage.