A geological survey found that a large deposit of the natural mineral illite has been discovered in Yeongdong County, North Chungcheong Province. Yeongdong County expects it to be the world's largest.
Yeongdong County said on the 21st that, based on a joint "illite mine reserve survey" conducted with the Korea Institute of Geoscience and Mineral Resources (KIGAM), the total illite reserves in the area are estimated at about 104.5 million tons (t).
That is 20 times the typical reserve threshold for a large clay deposit, which is about 5 million t. Yeongdong County said even the reserves of major overseas illite deposits, including those in China, are only in the several million tons.
The survey analyzed the deposit's extent and grade through 28 boreholes. As a result, 67.7% of the total reserves fall within the 40%–45% grade range, indicating high industrial value. In particular, very high illite content—up to 98% by fine-particle criteria—and excellent mineralogical properties were confirmed, underscoring its potential as a functional material.
Illite is a type of clay mineral first discovered in 1937 in Illinois, United States. With characteristics such as heavy metal adsorption, antibacterial action, deodorization, reduction of hazardous substances, and far-infrared radiation, it is known as a "mysterious mineral."
Illite is being used not only in building materials, fertilizers, and feed but also increasingly in cosmetics, health supplements, and environmental materials. Recently, its plant growth–promoting effects have been confirmed, drawing attention in agriculture as well. One study found that bean sprouts grown using illite had 1.9% and 11.2% higher vitamin C and mineral content, respectively, compared with conventional cultivation.
Based on the survey results, Yeongdong County plans to foster the illite sector into a high value-added industry by building standardization and certification systems and expanding support for corporations.
A Yeongdong County official said, "We have objectively confirmed the potential for illite to grow into a world-class strategic mineral resource," adding, "We will develop Yeongdong into the hub of the global illite industry."