Tsendjav L. Justification of geotechnical parameters for mining of uranium deposits in Mongolia

The results of industrial, laboratory and theoretical studies on the justification of geotechnical parameters of mining of hydrogenic uranium deposits in eastern Mongolia "Haraat", "Khairkhan", "Gurvan - Sayhan" and "Ulzit" are defenced. The methods of research on evaluation of uranium components in ores and the ranges of the physical and radiological property variation, as well as the patterns of in the uranium leaching rate depending on concentration of sulfuric acid and additives for technological solution have been analyzed and justified. The methods of performing the studies of physical and chemical properties of uranium ores have been developed. The industrial studies were carried out with using mechanical and geophysical methods; laboratory tests were performed by geochemical methods. Theoretical studies were performed by mathematical modeling, and physical and chemical methods. The proposed "by-layer" approach to preparation of separate ore bodies at different depths is determined by the structure of rocks of permeability varying from 1,16 to 11,6 Darcy, which allows successive leaching of ore bodies by wells with different diameters and filter design. This reduces the costs of drilling geotechnical wells more than 2 times, and shortens time for processing of uranium deposits in Mongolia. The rational distance between pumping and extracting wells ranged from 12,5 to 44,3 m is justified by the exponential function depending on saturation of the lecheats that for the seasonality of mining allows extracting from 74 to 97% of available reserves of uranium. The results of feasibility studies of geotechnological parameters of uranium deposits in Mongolia have been adopted to implement in the projects of Uranium Power Company "Mon-Atom". Implementation of the proposeg engineering solutions enables saving of more than $ 2,5 million a year for each of these deposits.