Mining Institute, Kola Science Center, Apatity, Russia:

V. V. Rybin, Leading Researcher, Doctor of Engineering Sciences, rybin@doi.kolasc.net.ru

An increase in an open pit mine depth results in higher volume of stripping and ends with transition to underground mining. Alternatively, the original ultimate pit limits can be revised towards higher slopes of benches and pit walls. The current theoretical approaches to geomechanical validation of table pitwall slopes omit actual stress state and block hierarchical structure of rock mass. The newly proposed methodical approach to pitwall slope stability takes into account natural gravitational and tectonic stresses, as well as block hierarchical structure of rocks. The proposed procedure for geomechanical validation of pitwall slope stability complies with features of high-strength rock masses and is applicable in open pit mines operating in such conditions. To this effect, it is required to examine geomechanical behavior of rocks. In Zhelezny open pit of Kovdorsky Mining and Processing Works, at Central Mine and in Niorkpakhk OP at East Mine of APATIT, stresses are measured at the faces of cores using the stress relief method. The proposed procedure consists in the analysis of the mathematical modeling results on distribution of stresses and strains in pitwall rock mass.

The studies have been supported by the Russian Science Foundation, Grant No. 14-17-00751: Basic and Exploratory Research Implementation by Separate Scientific Teams.

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