Application of layered gravel-filling hole structure for in-situ leaching of multilayer sandstone uranium deposit

For multilayer sandstone uranium deposit, two or more filter layers have to be constructed in order to implement different mining process for each layer in one drilling hole. According to the character of multilayer sandstone uranium deposit, on the basis of gravel-filling hole structure construction technology, layered gravel-filling hole technology is employed to construct two filter layers by man-made aquifuge in one time. The practice shows that the method of using layered gravel-filling hole structure to construct filter layers for each aquifer has the advantages of simple operation, short construction period, once-through well construction and low drilling hole cost. (authors)