Geophysical exploration of the giant Bayan Obo REE–Nb–Fe deposit in Inner Mongolia, China: Progress and challenges

Abstract

The Bayan Obo giant rare earth element (REE)–niobium (Nb)–iron (Fe) deposit, located in Inner Mongolia, is recognized globally as a significant comprehensive deposit and serves as a crucial rare resource base in China. Despite nearly seven decades of mining operations, numerous scientific questions pertaining to the Bayan Obo deposit remain unanswered, underscoring an urgent necessity to assess the quantities of rare resources and to explore alternative sources of iron ore. Addressing these issues is intrinsically connected to geophysical exploration efforts. In the past decade, extensive geophysical investigations have been conducted in the Bayan Obo mining region, resulting in substantial evidence that enhances the understanding of the deposit’s characteristics. However, practical exploration has demonstrated that the complex nature of the exploration targets, coupled with the environmental conditions in the Bayan Obo mining area, poses significant challenges to various geophysical exploration initiatives. This paper primarily reviews the advancements and achievements in geophysical exploration within the Bayan Obo mining area over the past ten years, while also examining the key challenges faced during these exploration efforts. Finally, several critical directions for future geophysical exploration activities are proposed.