Study of the relationship between the mining regime and the productivity of iron ore open pits

Abstract

Purpose. To study the variants of the mining operations regime that ensure the achievement of the maximum possible and planned ore production capacity of an open-pit mine, as well as to evaluate their impact on the area of feasible solutions for determining and averaging operational stripping ratios during the exploitation of deep iron ore deposits.

The methods. A comprehensive analysis of the spatial parameters of the open-pit working zone and their impact on the extraction intensity was used during the research. To determine the limits of regulating the mining operations regime, a grapho-analytical method was applied, involving the construction of cumulative graphs showing the dependence of overburden volumes on the extracted ore volume, V = f(P).

Findings. It is proven that on the cumulative graph V = f(P), the area of feasible solutions for determining and averaging operational stripping ratios has clear boundaries. These boundaries are formed by curves corresponding to the open-pit operation with a working bench width calculated according to two criteria: achieving the maximum intensity of mining operations development and the mandatory provision of a standard for ready-to-extract reserves. A key regularity is revealed: with a 10% increase in the target ore production capacity of the open-pit mine, the area for regulating the mining operations regime narrows by 10–14%.

The originality. For the first time, an analytical and graphical relationship between the mining operations regime and the open-pit ore production capacity has been established, taking into account the mandatory compliance with the standard volume of ready-to-extract reserves. It is proven that this standard volume is directly dictated by the spatial ratio of the working bench width to the active front length, which comprehensively determines the dynamics of the open-pit working zone formation.

Practical implementation. The obtained regularities provide a scientific basis for the flexible management of the spatial development of mining operations in deep open-pit mines. The proposed approach to averaging stripping ratios allows mining and processing plants to avoid peak loads concerning overburden volumes, optimize operating costs, and guarantee the stable loading of extraction equipment.