China’s rare earth reserves could be much larger than reported: leading geologist

But potential resources at massive Bayan Obo mine in Inner Mongolia do not automatically translate into economically recoverable reserves

The world’s largest known rare earth deposit in northern China could contain far more resources underground than currently reported, according to a leading Chinese geologist.

According to Yang Li, a Peking University geologist, “Bayan Obo’s rare earth resources have been the dominant source of global rare earth production since the 1990s.”

Even so, scientists now believe the currently reported figure of reserves may not represent the full geological potential of the region.

A 2025 study led by Yang found that Bayan Obo was not formed through a single geological event but through multiple stages of carbonatite activity – when volcanoes erupt runny, cool-burning lava made mostly of carbonate minerals – including a younger mineralisation event that played a vital role in forming the deposit.

“Our most important finding is that Bayan Obo not only contains 1,300 million-year-old igneous carbonatite but also 430 million-year-old carbonatite, and the second phase was key to mineralisation,” Yang said of the study published in the journal Science Advances.