The Kwisong Saltern began its salt production with this method last year and turned out more than 7 000 tons of salt in over 150 hectares of fields between early March and mid-May this year.

The Yonbaek Saltern changed all its production processes into those producing salt from underground ultra-saline water, increasing the salt production two to five times.

Such successes are also reported from other salterns in the country, which has rich underground ultra-saline water resources of high economic value.

The salt from underground ultra-saline water contains more potassium and iodine than that from seawater.

Since 2008 a work has been successfully done to secure promising deposits of underground ultra-saline water and drill for them at Kwisong, Namyang and Yonbaek salterns and Kwangmyongsong Saltern in the east coastal area of the country.