Institute of Mining, Ural Branch, Russian Academy of Sciences, Yekaterinburg, Russia:

I. V. Sokolov, Head of a Laboratory, Doctor of Engineering Sciences, geotech@igduran.ru
A. A. Smirnov, Senior Researcher, Candidate of Engineering Sciences
Yu. G. Antipin, Senior Researcher, Candidate of Engineering Sciences
I. V. Nikitin, Researcher

The article describes studies on justification of methodology for selecting geotechnology for transition zones in hybrid ore mining. The methodology is based on accounting for specific factors and conditions formed at the open pit mining stage and is aimed to ensure economic efficiency and safety of underground mining. The transition zone in the hybrid ore mining method is defined as an area of creation of optimal conditions for stable and safe underground operations based on specific accident-preventive measures undertaken. The transition geotechnology philosophy is formulated, and the technical-and-economic assessment algorithm for the technology scenarios is developed with regard to specific character, features and dynamics of operation. The geotechnology scenarios differ by the open pit mine quality (stable or damaged), mining direction (top-down or bottom-up), method and flowsheet to expose reserves (vertical shafts from the ground surface or transportation declines from the open pit), mining system in the transition zone (with caving ore with backfill), approach to sealing the transition zone from the open pit mine (a pillar or loose rock mass), system of mining basic reserves (with caving under loose rock mass, backfill under an ore pillar or under a backfill). The economic–mathematical modeling and feasibility study of the geotechnology scenarios have been performed using criterion of net profit value.
The article is based on the research implemented under State Contract No. 007-01398-17-00, Topic No. 0405-2015-0010.

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