Kovdorsky GOK JSC, Kovdor, Russia:

A. A. Danilkin, Technical Officer
S. N. Bocharov, Director of Development Engineering

Mining Institute, Kola Science Center, Russian Academy of Sciences, Apatity, Russia:

A. A. Kozyrev, Head of Rock Mechanics Department, Professor, Doctor of Engineering Sciences
V. V. Rybin, Head of Geomonitoring and Pitwall Slope Stability Sector, Doctor of Engineering Sciences, rybin@goi.kolasc.net.ru

The article presents the promising development concept for the Zhelezny open pit mine of Kovdorsky GOK JSC. The concept is based on the idea of forming a deep open pit at the preserved planned productivity, which is only possible through the close link between production and science. The article describes methodology of geomechanical substantiation of pitwall slope stability and the experience of its industrial application. The geomechanical substantiation of pitwall slope stability is based on the model approach consisting in sequential design of particular models (engineering geological and geomechanical models, limiting exposures, etc.) of rock mass enclosing the pit. It is shown that one of the most important features of adjacent rock mass in the Zhelezny open pit mine is the sub-horizontal stresses which are several times higher than vertical stresses. Another feature is hierarchical block structure of rock mass, which is also taken into account when developing particular models. Implementation of the proposed methodology for geomechanical substantiation of pitwall slope stability consists in selecting a test site and carrying out semi-commercial tests and experiments. Then, based on the data obtained, the regulations are developed for the ultimate pit limits design, which, in turn, is the basis of the ultimate pit limits project taking into account the rock mass peculiarities. The article exemplifies implementation of the mine’s innovative policy aimed at reducing the ore mining cost. This methodology of geomechanical substantiation of pitwall slope stability sufficiently suits to peculiarities hard high-strength rock masses and is applicable in different open pit mines in the in appropriate conditions.

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