Optimizing Stope Boundary and the Undercut Level in Block Cave Mining

Abstract

As near-surface mineral resources are being depleted, mining operations are focused on deepening. Rising environmental concerns prefer underground mining methods because their footprint is less than that of surface mining methods. Among the underground mining methods, block caving is a method with low operating costs and comparable production rate to open-pit mines. Mine design and planning optimization is performed to ensure the optimal use of mineral resources with minimal possible extraction costs. Stope boundary optimization is vital in the underground mining planning process, and numerous algorithms have been proposed in that regard. The floating stope algorithm is the most widely used algorithm which is presented for those mining methods where selective mining is possible. This paper tries to apply the floating stope algorithm for stope boundary optimization in the case of block caving. In that regard, a framework is discussed to determine the input parameters of the floating stope algorithm that are suited for block caving including minimum block size, floating ranges, and cutoff grade. These parameters are defined to customize the floating stope algorithm for the block caving method. Then the customized algorithm is applied to optimize the boundary of the underground block caving stope. Then, the corresponding undercut level is determined using the “effective cross-section” heuristic. The procedure is applied in the Songun copper mine. Based on the results, the minable reserve is 617 million tons with an average copper grade of 0.53%.

Keywords

• block caving
• undercut level
• stope boundary optimization