NorNickel’s Polar Division, Norilsk, Russia:

V. P. Marysyuk, Chief Geotechnical Engineer—Director of the Geodynamic Safety Center, Candidate of Engineering Sciences
S. Yu. Shilenko, Deputy Director of the Industrial and Occupational Safety Department

Gipronikel Institute, Saint-Petersburg, Russia:

A. V. Trofimov, Head of Geotechnical Engineering Laboratory, Candidate of Engineering Sciences, TrofimovAV@nornik.ru
A. E. Rumyantsev, Chief Specialist, Candidate of Engineering Sciences

Ore mining in the Talnakh and Oktyabrsky fields using stoping methods includes construction and support of many temporal and permanent ore passes for ore haulage by gravity, which is the commonly known effective and cost-saving technology. Despite all benefits, there are some geotechnical complexities. For instance, making ore passes with smaller diameter increases their stability, which allows using them in difficult ground conditions, on the one hand, and, on the other hand, this can lead to frequent ore flow arching phenomena in ore passes and, consequently, to the increase in efforts for their elimination. This paper presents summary recommendations for selecting the cross-section shape and dimension of an ore pass based on global practice. The approach to determining the ore pass diameter with regard to grain sizes and properties of ore flow is substantiated. A series of experiments for determining the physical and mechanical properties (cohesion and internal friction angle) of ore mixture with a given particle size distribution at various degrees of moisture is carried out. Considering the determined properties, the minimum diameter of an ore pass to provide ore flow without formation of cohesive and interlocking arches is calculated. It is found that at the ore pass diameter of 2.4 m and at the maximum lump ore size of 254 mm, the material with natural moisture flows freely without arching in the ore pass.

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