A river of rare resources
The Anning River valley is part of the Mianning-Dechang REE belt, a geological feature that stretches 270 kilometers long and 15 kilometers wide. This region in Sichuan province contains one of the world's most significant concentrations of rare earth elements (REEs), the materials for high-performance magnets, electronics, and renewable energy technologies. The river itself has created a vast placer deposit, where valuable minerals, weathered from their original rock, have been concentrated by the flow of water over long periods.
The source of these elements is the Maoniuping carbonatite complex, a massive igneous intrusion located upstream. This complex has total resources of more than 5 million tonnes of rare-earth oxide (REO). Over millions of years, weathering has broken down REE-bearing minerals like bastnäsite from the complex. These minerals then move downstream, carried by the Anning River. The river's currents act as a natural separator, sorting the heavier mineral particles from lighter sand and silt, creating concentrated deposits in the river sediments.