Exploration Methods for Potassium-Rich and Lithium-Rich Brine in the Mihai Mining Area, Qaidam Basin, Qinghai

The exploration and extraction of deep salt lake resources are of great significance for alleviating potassium and lithium resource shortages. However, large-scale industrial extraction has not been achieved due to technical challenges and cost constraints. This study focuses on the Mihai Mining District in Qaida Basin, Qinghai Province, investigating the exploration and development of deep confined brine enriched with potassium and lithium. The Mihai Mining Area boasts vast reserves of deep confined brine, however, they are not well-utilised because of their heterogeneity, low water yields, and extremely low mining efficiency. Previous studies have revealed that the high-yield wells in mining areas are located within fault zones. Therefore, based on the theoretical models of ‘brine circulation and potassium formation in fault zones’ and ‘storage of brine in steeply inclined water-collecting corridors’, an efficient exploration technique is proposed, which focuses on identifying active fault zones within areas with well-developed high-quality brine reservoirs as key target areas. This study employed radar remote sensing interpretation of pre- and post-seismic deformation intensity to infer fault zone development areas. Integrated with radon gas measurements, the results confirm the presence of a NE-striking active fault within the key target zone. Functioning as the sedimentary centre, this zone exhibits highly concentrated brine with co-enrichment of K⁺ and Li⁺ (both elements showing anomalously high concentrations), indicating high potential for K-Li-rich brine discovery. Guided by the exploration theory, verification drilling revealed brine with elevated K-Li concentrations (approximately double those in adjacent areas) and high-yield water flows in most boreholes, demonstrating significant exploration success. The distribution pattern of the discovered high-yield, water-rich areas and the exploration prediction method are of great significance for the development of deep brine in the Mihai Mining Area and have considerable potential for promotion in the Qaida Basin.