China has discovered an additional 9.67 million metric tons of rare earth oxides in Mianning county, Sichuan province, raising the total to 11.46 million tons, the Ministry of Natural Resources said on Tuesday.

The increase makes the county's Mao-niuping deposit the world's second-largest in-production source of light rare earth elements, behind the Bayan Obo site in the Inner Mongolia autonomous region.

In the Maoniuping mining area, newly found resources were also identified alongside the rare earth reserves. These resources include 27.14 million tons of fluorite and 37.23 million tons of barite, both of which are classified as ultra-large deposits of strategic importance.

Light rare earth elements — including seven of the 17 rare earth elements — are relatively abundant in the Earth's crust in oxide form compared with heavy rare earth elements. Often dubbed the "vitamins" of industry, these are widely used in magnetic and fluorescent materials and are indispensable to modern industry and high-end manufacturing.

Ming Tianxue, a researcher at the Yunnan Geological Survey, said that China is rich in light rare earth resources, with the world's largest deposit at Bayan Obo and the second-largest at the newly expanded Maoniuping site.

The Maoniuping rare earth deposit has been exploited since it was first discovered in the 1980s. This exploration, which targets deep-seated ores, represents breakthroughs in both metallogenic theory and exploration technology, Ming said.

"The new discovery is of great significance for securing national strategic reserves — not only for this deposit itself, but also for the exploration of similar deposits," he said, adding that China now has a relatively complete industrial chain spanning the extraction, processing and manufacturing of light rare earth elements.

To address challenges such as high altitude and difficult positioning in the mining area, geological workers incorporated artificial intelligence algorithms into mineral exploration. By leveraging multisource survey data, they conducted intelligent analysis, modeling and target area prediction, significantly improving the accuracy and efficiency in identifying ores.

The method is expected to facilitate the exploration of deep-seated and peripheral areas of known deposits in regions with complex geological structures.

Zhao Wen, an associate professor at China University of Geosciences in Wuhan, Hubei province, stressed the strategic importance of the discovery, saying that the additional 9.67 million tons of rare earth oxides are equivalent to about 36 years of China's current consumption of light rare earth elements.

"This discovery has the potential to reshape the global rare earth supply landscape. China now has two world-class light rare earth cornerstones, greatly enhancing the resilience and risk resistance of its supply chain," Zhao said.

He added that the discovery strengthens China's ability to manage international market price fluctuations and geopolitical competition, particularly as Japan seeks to involve the United States in deep-sea rare earth mining projects.

Zhao also highlighted the economic and strategic value of the associated minerals — fluorite and barite. Fluorite, a nonrenewable resource, is a key source of industrial fluorine essential to the chipmaking and new energy industries. The raw ores are estimated to be worth 100 billion yuan ($14.5 billion), while deep-processed products such as electronic-grade hydrofluoric acid could be valued at roughly tens of times that amount.

Barite, which is known for its chemical inertness, resistance to acids and alkalis, high density and radiation absorption properties, is widely used in natural gas exploration and extraction.

The discovery marks a new achievement in China's latest round of mineral exploration breakthroughs and aligns with the 15th Five-Year Plan (2026-30), which emphasizes strengthening the exploration, development and reserves of strategic mineral resources to maintain competitive advantages in key resources such as rare earth elements.

limenghan@chinadaily.com.cn