Fokin V. A., Leading Researcher, Doctor of Engineering Sciences, e-mail: fva666@goi.kolasc.net.ru, Mining Institute of Kola Scientific Center of the Russian Academy of Sciences; Melik-Gaikazov I. V., The First Deputy of Executive Director — Technical Director, Candidate of Engineering Sciences, Togunov M. B., Leading Expert of Engineering Development Department, Shitov V. A., Deputy Chief Engineer of Mine of Drilling and Blasting Operations, Kovdorsky Mining and Concentrating Plant

In technology of bank slope work of open-cast mine ledges at their statement in final position, diameter of linear charges of planimetric chinks, unlike crushing charges on working blocks, makes 1/3–1/4 diameters of a chink, and their specific weight (on one meter of a chink) becomes less on an order and more. A priori it is considered that even simultaneous explosion of group of planimetric charges is essentially smaller on intensity of seismic influence, than borehole charge breaking on the working blockat for such essential difference in linear density. The possibility of seismic hazard estimation of blasting operations, taking into account criteria of their weaken influence on rock mass is substantiated on the base of analysis of data of seismic measures during large-scale blast of two grinding blocks and chink-forming contour charges between the blocks. Usage of charges with reduced diameter with well after well initialization during formation of cutoff stopes and blasting of sub-contour blocks is recommended as effective method of dynamic force reducing on rock mass during quarry bank staging in finish position. Results of researches and trial works have shown that correct and physically well-founded estimation of degree of seismic danger of explosive works by their criterion of weaken influence actions on surrounding pedigree file can be received by the analysis of seismogram with use of corresponding power parameters. Thus the basic direction of decrease in the general level of dynamic loading on a pedigree file is use of chinks of the reduced diameter as at formation of a detachable crack with the most effective order of detonation of planimetric charges, as well as at detonation of sub-contour blocks with with well after well delay of charges of crushing.

1. Fokin V. A., Melik-Gaikazov I. V., Togunov M. B., Shitov Yu. A. Gornyi Zhurnal — Mining Journal, 2010, No. 7, pp. 65–67.
2. Fokin V. A. Vzryvnoe Delo — Blasting Work, 2009, No. 102/59, pp. 91–102.
3. Melik-Gaikazov I. V., Togunov M. B., Shitov Yu. A. Gornyi Zhurnal — Mining Journal, 2011, No. 4, pp. 95–97.