Belgorod State University, Belgorod, Russia:

I. M. Ignatenko, Director of the Institute of Earth Sciences, Candidate of Engineering Sciences
V. A. Dunaev, Professor, Doctor of Geologo-Mineralogical Sciences
V. N. Tyupin, Professor, Doctor of Engineering Sciences, tyupinvn@mail.ru

Efficiency of hard mineral mining by the opencast method is in many ways governed by blasting quality, while the latter depends on natural jointing and hardness of rocks, as well as on drilling-and-basting design. In terms of Vostochny open pit mine, Polyus, procedure of full-scale examination of exposed rock mass in vertical and horizontal directions is improved. Using a representative sampling of actual data (808 319 measurements in rocks of 7 petrographic types) within the limits of Vostochny open pit mine, the following features of exposed rock mass are identified: considerable range of size of joints (0.11–2.13 m) and average size of joints in each petrographic type (0.36–0.91 m); clear trend of intensification of jointing with increasing depth (520 m vertically down). The mathematical model is developed for prediction of size in rock fragmentation by blasting with regard to the energy conservation law and effect of blasting environment in a rock block. The formula is proposed for determining average size of rock fragmentation by blasting depending on drill-and-blast process parameters and natural properties of rock mass. Based on the interactive map of rock blastability, the procedure is developed for on-line computation of drill-and-blast design parameters and pre-project assessment of blasting quality in any area of an open pit mine with the known jointing and hardness of rock mass. Application of this procedure will enable improved quality and shorter time of blasting in extraction blocks.

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