Abstract:Acid in-situ leaching of uranium is one of the most commonly used mining methods for sandstone-type uranium deposits. Due to high acid solution injected into underground ore-bearing layer in in-situ leaching, permeability of ore-bearing layer is often reduced by chemical precipitation blockage, and efficiency of uranium leaching is reduced. Therefore, it is necessary to explore variation characteristics of groundwater (solution) flow rate during in-situ leaching. Groundwater tracer test was carried out in C10 mining area of Bayanwula uranium mine. The test results show that there are multiple (at least two) seepage channels from injection hole to extraction hole. Flow rate of solution in faster channel is 1.95—2.06 m/d, and that in slower channel is 1.35—1.44 m/d. Flow velocity characteristics of leaching solution obtained by KI tracer test and SO42- tracer test corresponds to each other.