A Path Search Algorithm for Optimizing Ultimate Limit of Open Pit Mines with Geomechanical Constraints
N. Babanouri, H. Dehghani, M. Khodaveisi
Department of Mining Engineering, Hamedan University of Technology, Hamedan, Iran
Keywords: Open pit mine, ultimate pit limit, benefit, path search, optimization, geomechanical constraints
Abstract
In this study, a path search algorithm is introduced for exploring the ultimate pit limit using the Lerchs-Grossmann method. In an iteration of the algorithm, each vertex of the solution is randomly moved within a specified neighborhood. The vertices’ motion in such a neighborhood ensures that the formation of abnormal shapes is prevented. Since an open-pit design needs to address geomechanical concerns coincident with economic value maximization, the movements resulting in segments steeper than an allowable slope angle are discarded. For each valid vertex movement, the benefit of the resulted pit limit was calculated. The new position of the vertex is accepted according to a probabilistic regime in order to prevent the algorithm be trapped in a local maximum. Independence of the slope from the block size is one of the main advantages of the suggested algorithm. Hence, the algorithm provides a better mapping to the ore body and results in a higher benefit. The reason is the mobility of the path search algorithm and its high flexibility.
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