IN-SITU RECOVERY. OPPORTUNITIES, CHALLENGES AND SOLUTIONS.

摘要

In-situ recovery (ISR) transfers a significant proportion of hydrometallurgical processing to mineralised bodies in the subsurface to directly obtain solutions of metals of interest. As a result, there is little surface disturbance, and no tailings or waste rock are generated at ISR mines. However, for ISR to be successful, deposits need to be permeable (either naturally or artificially induced), and the metals of interest readily amenable to dissolution by leaching solutions over a reasonable period with an acceptable consumption of leaching reagents. ISR of uranium, gold and copper is common, with the share of uranium mined by ISR accounting for more than 50% of world production. ISR of other elements such as nickel, cobalt, rare earths, scandium, molybdenum has been successfully developed over recent years. However, implementation of ISR has serious challenges due to variability in deposit geological and hydrogeological conditions, as well as mineralogical composition. Initial testing of commercial blocks is often complicated, however, technical issues can often be solved through the execution of appropriate work programmes. Environmental issues also require consideration. Contamination of groundwater by ISR reagents is a critical aspect requiring management. The ISR industry has developed solutions for technical challenges such as specific approaches for exploration and geological modelling, calibration of lixiviant composition, the timing of leaching and construction of wells, repair and restoration works, and modelling of ISR processes.This paper provides examples where technical solutions have been developed for ISR projects across a range of commodities in a variety of different conditions.