Institute of Mining of Siberian Branch of Russian Academy of Sciences (Novosibirsk, Russia):

Eremenko A. A., Head of Laboratory, Doctor of Engineering Sciences

Institute of Comprehensive Exploitation of Mineral Resources of Russian Academy of Sciences (Moscow, Russia):
Eremenko V. A., Leading Researcher, Doctor of Engineering Sciences, e-mail: eremenko@ngs.ru

Gorno-Shorsky branch of “Evrazruda” JSC (Tashtagol, Russia):
Shchetinin E. V., Head of Mine
Shultaev S. K., Chief Engineer of Mine

Starting of mining operations at the deeper level causes the increasing of rock pressure and changing of physical and mechanical properties of rocks. Iron ore deposits in West Siberia are situated in the regions of present-day tectonism of subsoils. Horizontal stresses are by 1.3–2.6 times higher than vertical stresses beyond the stoped excavation zone, and by 3.5–5.2 times higher than vertical stresses in the stoped excavation zone. Depth of mining operations at deposits reached 1050 m. Using the development system of induced block caving with whole continuous working of ore bodies makes it possible to have a control over rock pressure by means of waste backfilling by caved surrounding rocks. Blasting operations make the most significant influence on the rock massif. Weight of explosive charge in small-scale and large-scale blasts is 0.7–20 t on average and 120–370 t on average, respectively. This weight varies from 0.5 to 800 t. According to this, there takes place the failure of massif with capacity from 30 to 250 th. m³. The carried out analysis of parameters of drilling and blasting operations has shown that the blasts are often followed with tremors, which may take place in a few seconds, hours or days. The energy class of blasts varied between 4.3 and 8.3 at different ore locuses. At the same time, the powder factor varied between 512 and 645 g/t. There was held the analysis of breaking of a Block No. 4, located in blind ore body in Podrusloviy mining district. According to this analysis, there can be noted, that application of parallel-contiguous deep hole explosive charges with increased diameter made it possible to reach the qualitative ore breaking with reduction of a seismic effect of the blast in rockburst-hazardous massif. This research work was held with a financial support of a Ministry of Education and Science of Russian Federation.

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4. Eremenko A. A., Eremenko V. A., Filippov V. N. et al. Gornyy Informatsionno-Analiticheskiy Byulleten — Mining Informational and Analytical Bulletin, 2007, No. 11, pp. 96–100.
5. Medvedev S. V. Seysmika gornykh vzryvov (Seismic survey of mining blasts). Moscow : Nedra, 1964.