Exploitation
Meisam Saleki; Reza Khaloo Kakaie; Mohammad Ataei; Ali Nouri Qarahasanlou
Abstract
One of the most critical designs in open-pit mining is the ultimate pit limit (UPL). The UPL is frequently computed initially through profit-maximizing algorithms like the Lerchs-Grossman (LG). Then, in order to optimize net present value (NPV), production planning is executed for the blocks that ...
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One of the most critical designs in open-pit mining is the ultimate pit limit (UPL). The UPL is frequently computed initially through profit-maximizing algorithms like the Lerchs-Grossman (LG). Then, in order to optimize net present value (NPV), production planning is executed for the blocks that fall within the designated pit limit. This paper presents a mathematical model of the UPL with NPV maximization, enabling simultaneous determination of the UPL and long-term production planning. Model behavior is nonlinear. Thus, in order to achieve model linearization, the model has been partitioned into two linear sub-problems. The procedure facilitates the model solution and the strategy by decreasing the number of decision variables. Naturally, the model is NP-Hard. As a result, in order to address the issue, the Dynamic Pit Tracker (DPT) heuristic algorithm was devised, accepting economic block models as input. A comparison is made between the economic values and positional weights of blocks throughout the steps in order to identify the most appropriate block. The outcomes of the mathematical model, LG, and Latorre-Golosinski (LAGO) algorithms were assessed in relation to the DPT on a two-dimensional block model. Comparative analysis revealed that the UPLs generated by these algorithms are consistent in this instance. Utilizing the new algorithm to determine UPL for a 3D block model revealed that the final pit profit matched LG UPL by 97.95%.
J. Gholamnejad; A.R. Mojahedfar
Abstract
The determination of the Ultimate Pit Limit (UPL) is the first step in the open pit mine planning process. In this stage
that parts of the mineral deposit that are economic to mine are determined. There are several mathematical, heuristic
and meta-heuristic algorithms to determine UPL. The optimization ...
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The determination of the Ultimate Pit Limit (UPL) is the first step in the open pit mine planning process. In this stage
that parts of the mineral deposit that are economic to mine are determined. There are several mathematical, heuristic
and meta-heuristic algorithms to determine UPL. The optimization criterion in these algorithms is maximization of the
total profit whilst satisfying the operational requirement of safe wall slopes. In this paper the concept of largest pit with
non- negative value is suggested. A mathematical model based on integer programming is then developed to deal with
this objective. This model was applied on an iron ore deposit. Results showed that obtained pit with this objective is
larger than that of obtained by using net profit maximization and contains more ore, whilst the total net profit of
ultimate pit is not negative. This strategy can also increase the life of mine which is in accordance to the sustainable
development principals.
