Sandstone-type uranium deposits in China: current research status, future agenda, and a critical review

Abstract

Sandstone-type uranium deposits have become a vital component of China’s uranium resources. Breakthroughs have been achieved in uranium exploration technology, mineralization, leaching process innovation, and post-leaching environment remediation. Exploration is no longer limited to the traditional “grey-black” stratigraphic but has innovatively incorporated the concept of “red-black coupling,” significantly broadening the horizons and scope of exploration. At the theoretical level of uranium ore-forming, a series of ore-forming models have been successfully introduced and deeply studied, including hydrothermal superposition mineralization, bio-mineralization, hydrocarbon reduction mineralization, and exudative mineralization. These mechanisms have not only greatly enriched our understanding of the genesis of sandstone-type uranium deposits but also provided a more solid theoretical foundation for ore-finding practices. In in-situ leaching field, the more environmentally friendly, economical, and efficient CO₂+O₂ leaching has been widely applied. However, the latest environmental assessment results indicate that both H₂SO₄ and CO₂+O₂ leaching processes require a long period of natural remediation to meet regulatory requirements. Therefore, implementing scientific and effective environmental remediation measures for decommissioned areas has become a top priority. Interdisciplinary collaboration is the key force driving the sustainable and resilient development of uranium resources in China. Future research directions will focus on four main aspects: (1) Researchers will develop high-precision analytical techniques and create homogeneous U-Pb dating reference materials to accurately determine the minerals’ geochemical composition and mineralization age. (2) Researchers will integrate multi-source data, including uranium leaching processes, post-leaching environmental remediation, and fluid inclusions in ore-forming fluids, with computer numerical simulation techniques. This integration will facilitate the study of uranium’s migration, enrichment, and precipitation mechanisms in ore-forming environments, thereby enhancing the understanding of its geochemical behavior. (3) Researchers will enhance research in process mineralogy, ion kinetics of leaching fluids, and changes in geological structural physical properties. This research will provide new ideas and methods for addressing practical challenges in uranium leaching. (4) Researchers will closely link theoretical research with practical operations. This linkage will help develop scientific management policies, strengthen legal frameworks, and promote industry standards, ensuring the smooth progress of decommissioned mine remediation and achieving the goal of sustainable green mining.