Substantiation of technological solutions for uranium mining by the method of In-Situ Leach Mining (ISL) under the conditions of the high groundwater pressure. Methods. Analysis of mining-and-geological conditions of the deposit, conducting experimental-industrial works at the experimental unit, and processing data from research results. To increase the efficiency and reduce the expenditures for insitu leach mining of uranium, taking into account the hydrogeological peculiarities of the deposit, experimental works have been conducted using the "pumping wells" technology. Findings. The proposed technology helps to reduce the expenditures for acquiring cable products, submersible pumps (the cost of a more powerful pump is much less than the cost of several ones, which are equal to it in power), for the construction of well heads. The dependences have been obtained of the change in the uranium content in the pregnant solution and the recovery coefficient on the L:S ratio (liquid to solid) using the "pumping wells" technology. With a change in L:S from 0.1 to 0.33, the uranium content in the pregnant solution increases from 5 to 225 mg/l, then its gradual decrease is observed. A change in L:S from 0.9 to 2.2 leads to an insignificant change in the uranium content to 100-120 mg/l. Originality. Based on the research results, the dependences have been obtained of the change in the uranium content in the pregnant solution and the recovery coefficient on the ratio of L:S using the "pumping wells" technology. The recovery coefficient has changed in direct proportion to the L:S ratio, hence, for L:S from 0.1 to 2, the recovery coefficient i ncreases from 1 to 87%. Practical implications. A new technology for uranium mining by the method of underground leaching has been developed, which is characterized by low capital expenditures and producing costs of in-situ leach mining of uranium.

Purpose is to increase a sorbent denitration degree in the context of underground uranium leaching while optimizing reagent concentration as well as a degree of the solution activation on the basis of laboratory research. Methods. Analysis has been applied as well as scientific generalization of scientific-and-engineering information, laboratory research, statistic processing, and analysis of the research results. The laboratory experiments involved specific mixture to obtain comparative data of sulfuric solution activity and identify optimum degree of the solution activation for denitration. After processing, the solution from activator was analyzed as for its activity; the bulk was poured into a tank for repetitive experiments. First, the research did not involve the solution activation; then, activation with 4-15 minutes was added. Sulfuric acid concentration was 20 and 25 g/dm3; L-S ratio was 1/8; and washing time was 40, 60, and 120 minutes. Findings. Laboratory research results have been demonstrated concerning sorbent denitration in terms of varying degrees of activation, sulfuric acid concentration, and response time. It has been demonstrated that it is sufficient for washing solution activation to activate reagent only before extra intensification of a mother solution resulting in the reduced volume of the solution being processed and costs. It has been determined that five- to nine-minute activation period is the efficient interval factoring into the decreased nitrate content in the sorbent after washing to compare with 9-18% in terms of a basic technique depending upon a reagent concentration. Originality.New dependences of a sorbent denitration degree as well as nitrate content within a solution upon sulfuric acid concentration and the solution activation degree have been defined. Practical implications. Washing solution activation results in the increased denitration degree of a sorbent to compare with the basic technique. The proposed method is more preferable owing to low capital costs. Moreover, it is integrated easily in the available system being also absolutely sustainable. Keywords: denitration, sorbent, sorption, desorption, activation, sulfuric acid, uranium

Study of application of «pumping wells» when mining of uranium deposits by in-situ leaching (ISL) to the mine "Karatau" under conditions of high pressure of groundwater character was performed. The operating «Karatau» mine is located in a deserted, inaccessible, sparsely populated area in the southwestern part of the Shu-Sarysuy depression in the territory of the Suzaksky district, Turkestan oblast. The «Karatau» deposit differs from other deposits in that self-pouring of geotechnological wells with a statistical level of +20 m is observed at all sites. The use of traditional technology for such deposit leads to excessive material and labor costs. Therefore, the technology of "pumping wells" is proposed. It is shown that the use of "pumping wells" procedure leads to achieving a uniform flow rate of extraction wells, reduction in the purchase of the cable production costs for the purchase of submersible pumps and wells in the end cap.