Nosov Magnitogorsk State Technical University, Magnitogorsk, Russia
V. N. Kalmykov, Doctor of Engineering Sciences, Professor
K. V. Burmistrov, Doctor of Engineering Sciences, Professor, Associate Professor
S. E. Gavrishev, Head of a Department, Doctor of Engineering Sciences, Professor
S. N. Kornilov, Doctor of Engineering Sciences, Professor, kornilov_sn@mail.ru

UralEnergoResurs LLC, Magnitogorsk, Russia

A. A. Zubkov, CEO, Doctor of Engineering Sciences

Institute of Mining, Ural Branch, Russian Academy of Sciences, Yekaterinburg, Russia
O. V. Zoteev, Leading Researcher, Doctor of Engineering Sciences, Professor

The article presents the studies on the rationale for the extraction of iron ore reserves beyond the ultimate pit limit at the Malyi Kuibas mine using the underground mining method. One of the most complex and multi-variate challenges was the choice of a method of getting access to the reserves because of the lack of reliable geological information. The study took into account the geological features of the structure of the deposit, the open pit parameters by the end of operations, and the physical layout of the aboveground infrastructure. Selection of efficient flowsheets for iron ore mining was complicated by the lack of the anticipatory solutions on the transition from the open pit to underground mining. For instance, by the open pit mining phaseout, no attempts were undertaken to estimate feasibility of arrangement of access headings in the void of the open pit, or to assess potential of internal dumping for making a parting layer of rocks and for reducing amount of stone drivage, and no decision was made on location of external overburden dumps in coordination with patterns of access borehole drilling, which greatly complicated the choice of an opening-up method and elevated the cost of the mine construction. All in all, 12 potential scenarios of getting access to the reserves to be additionally extracted were selected, with different types and arrangement of access headings on ground surface and within the open pit. Amounts of stone drivage were compared in all scenarios, and, on this basis, four variants of getting access to underground ore reserves, with the smallest amounts of stone drivage were selected. The feasibility studies of the projects were carried out and the most promising and suitable mining scenario was adopted.

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