VNIPIpromtekhnologii R&D Institute, Moscow, Russia:
E. N. Kamnev, Academic Secretary, Doctor of Geologo-Mineralogical Sciences, Kamnev@vnipipt.ru
A. M. Ioffe, Head of Laboratory, Candidate of Engineering Sciences
D. V. Velichko, Leading Engineer

Priargunsky Mining and Chemical Works, Krasnokamensk, Russia:
D. V. Tyurin, Chief Surveyor

The article presents the research findings on validation of a safe mining technology for uranium deposits of Priargunsky Mining and Chemical Works, Krasnokamensk, Transbaikal Territory. The modern methods are proposed for calculating stable exposures and mined-out spans in extraction of ore reserves using the room-and-pillar and slicing systems. The information on the nature and alteration of rock mass over a long period of time was taken into account in the calculations. The field of application of selective extraction from thin deposits is identifi ed. Safe parameters of ground surface undermining at complete extraction of ore reserves from block 4a-703 in Streltsovskoe ore field are found by numerical modeling. Using the developed procedure for validation of the selective mining technology applicability in mines of Priargunsky Mining and Chemical Works, it is ascertained that selective extraction is economically expedient in ore bodies 0.9^–1 m thick. The procedure includes finite element method for estimation of stope stability depending on height of cemented backfill. Safety of decreasing the size of backfill from 81 to 67% in mined-out stopes is validated, which provides economic efficiency of 144 MRub annually.
The authors appreciate participation of A. V. Seleznev, Candidate of Engineering Sciences, Head of Science and Technology Department, VNIPIpromtekhnologii, in this study.

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