Institute of Integrated Mineral Development — IPKON, Russian Academy of Sciences, Moscow, Russia:

V. A. Eremenko, Leading Researcher, Professor of RAS, Doctor of Engineering Sciences, eremenko@ngs.ru

Institute of Mineralogy, Geochemistry and Crystal Chemistry of Rare Elements, Moscow, Russia:
N. G. Barnov, Researcher, Candidate of Geologo-Mineralogical Sciences

Chinakal Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia:
A. S. Kondratenko, Director, Candidate of Engineering Sciences
V. V. Timonin, Head of laboratory, Candidate of Engineering Sciences

For complicated geological and geotechnical conditions of steeply dipping thin lodes, a method has been developed, including bench mining with drilling and blasting (hydraulic blasting) and simultaneous backfilling with barren rocks. Concurrent mining on three (four) sublevels, sequence of preparation of an extraction panel and actual stoping enables continuous operation and enhanced efficiency of the geotechnology. Mechanized backfilling with barren rocks minimizes costs of barren rock transportation and disposal. This geotechnology is aimed at the most complete extraction of minerals with the raise mining starting from the lower boundary of an ore body (block). The proposed geotechnology eliminates crown pillars and stress concentration zones. A block of an ore body is divided into 4 sublevels with 8 work faces. In accessing, the length of retreat mining from sides to the center of the block is shortened, e.g., to 125 m, with regard to physical properties of ore and enclosing rocks. Mining efficiency is ensured by: high production output of the mining system; feasibility of concurrent operation on 3–4 sublevels; drilling and charging of holes from the upper lying drift on a sublevel; application of advanced drilling equipment designed at the Institute of Mining, Siberian Branch, Russian Academy of Sciences; no need in crown pillars; capability to carry out stoping in unstable enclosing rocks of hanging wall owing to cable rock bolting; safe remote loading of broken ore in production face area, etc. The full-scale research in mines show that in ore heading with drilling and blasting and ore handling in excavations driven in footwall, ore dilution makes 5 %; under condition that blasting is directed toward backfill, this dilution value should be added with 40 % in the first blast row and 20 % in the second blast row.
The study has been supported by the Russian Science Foundation, Governmental Grant No. 14-37-00050.

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