Norilsk Nickel’s Polar Division, Norilsk, Russia:

V. P. Marysyuk, Chief Geotechnologist – Director of Center for Geodynamic Safety, Candidate of Engineering Sciences, marysyukvp@nornik.ru

Norilsk Nickel, Norilsk, Russia:

G. V. Sabyanin, Head of Mining and Processing Management, Production and Technology Department, Candidate of Engineering Sciences

Gipronikel Institute, Saint-Petersburg, Russia:

A. V. Trofimov, Head of Center for Physical and Mechanical Research, Candidate of Engineering Sciences

Saint-Petersburg Mining University, Saint-Petersburg, Russia:

A. P. Kirkin, Post-Graduate Student

The existing technology of ring blasting in stoping with backfilling in mines of Norilsk Nickel’s Polar Division is based on recommendations which avoid proknock effect of explosion, variation of physical and mechanical properties of ore body, applicability of new explosives and change in charging density. Incorrect drill and blast parameters in mining highly valuable ore with systems with backfill result in high loss and dilution. For eliminating deficiencies of the current drill and blast technology, the article proposes the blast pattern design procedure based on the calculation of fracture and spalling zones, moreover the series of physical and mechanical tests is performed, including determination of physical, strength and deformation characteristics of rocks in the Taimyrsky Mine. The analysis undertaken for calculation of fracture zones selected M. F. Drukovany’s research findings, involving the most of characteristics of explosive fracture of rocks, as well as their physical and mechanical properties. The rock test results can be used in designing drill and blast patterns under specific operating conditions. The proposed procedure takes into account the critical aspect of drilling and blasting in underground mines, namely, the influence of the effective stresses on the blast patterns. This aspect is included in the formula for determining sizes of zones of radial cracks. The calculation assumes the values of cohesion and internal friction of rocks with regard to Mohr’s circles as consistent with drilling and blasting under the stress state at characteristics depths of the Talnakh mines. With increasing effective principal stresses in rocks, their strength (cohesion) consistently grows while brittleness (internal friction angle) lowers, which shows itself as diminishing zone of radial cracks in blasting. The study also takes into account the zone of fracture by spalling in interaction with free surface.
The authors appreciate participation of A. A. Kisel, P. S. Guzanov, A. E. Lytneva, V. B. Vilchinsky and A. V. Fedoseev in this study.

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