Abstract:Injection flow rate of an in-situ leaching uranium mine drops dramatically. The reason is that solution near the drilling filter contains a large number of silicate substances, its chemical properties is stable, it does not react with any substance except strong alkali and hydrofluoric acid, and will condense to form silicate polymer and block the drilling. According to physical and chemical characteristics of silicate, well washing with NaOH process was proposed. NaOH solution was injected into borehole and reacted with silicate to produce soluble sodium silicate, so as to solve the problem of drilling blockage. The test and field application results show that well washing with NaOH can effectively improve the problem of hole silicate blockage and improve drilling fluid capacity.