Abstract:Uranium resources are not only the cornerstone of nuclear military industry but also the granary for the development of nuclear power. In the current complex international situation and the era of vigorously developing nuclear power, it is an indispensable and important resource. With the operation of in-situ leaching of uranium at Bayanwula uranium mine in Inner Mongolia, problems such as ore bed blockage and decreased uranium leaching amount are gradually emerging. In order to explore the evolution characteristics of the permeability of ore bearing layers during in-situ leaching of uranium, a cross-well tracer test was conducted in a certain experimental unit of the C10 mining area of the Bayanwula uranium deposit. The experimental results indicate that after one year of in-situ leaching, the porosity and permeability of the sandstone in the ore bearing layer decrease, which is related to the blockage of the pores in the sandstone in the ore bearing layer. After two years of in-situ leaching, the C10 mining area test unit has developed advantageous seepage channels in three seepage directions, namely KZ13238-KC13036, KZ13238-KC13038, and KZ13238-KC13438. After two years of in-situ leaching, the flow rate of the solution in the seepage channels in all directions decreases to varying degrees compared to that in the first year of in-situ leaching, and the downward decrease is greater than the previous year. It indicates that with the operation of the mining area, the pore blockage of the ore bearing layer is becoming increasingly serious, and the permeability of the ore bearing layer is continuously decreasing. The research results can provide tracer evidence for the evolution characteristics of the permeability of ore-bearing layer in in-situ leaching.