Mining Goes Digital – Mueller et al. (Eds)
© 2019 Taylor & Francis Group, London, ISBN 978-0-367-33604-2
443
Short-term open-pit mine production scheduling with
hierarchical objectives
F. Manríquez, H. González & N. Morales
DELPHOS Mine Planning Laboratory, Department of Mining Engineering and Advanced Mining
Technology Center (AMTC), Universidad de Chile, Santiago, Chile
ABSTRACT: Short-term mine scheduling in open-pit mines consists of meeting the objectives defined by the long-term mine production schedule. Short-term scheduling in open-pit
mines has multiple hierarchical objectives to optimize. This work proposes an optimization
methodology to generate a short-term open-pit mine production schedule optimizing multiple hierarchical objectives. For the generation of mine schedules, we propose an optimization model based on mixed-integer linear programming. This model considers the usual
restrictions of mine sequencing and also takes into account both time and cost of movement
between phases of each shovel. In order to optimize the multiple hierarchical short-term
objectives, we apply the hierarchical and weighted sum methods in the proposed optimization model. We verify this methodology in a real open-pit mine case study. The results show
that both methods generate short-term mine schedules optimizing the different short-term
objectives.
1 INTRODUCTION
Short-term mine scheduling in open-pit mines consists of meeting the objectives defined
by the long-term mine production schedule. Short-term scheduling in open-pit mines has
multiple objectives to optimize. In some mine operations, these objectives are ranked in a
descending order which are: (i) the minimization of the deviation between the ore sent to the
ore processing plant and the ore processing capacity of the plant per period, (ii) the minimization of the deviation between the metal fines sent to the plant and the fines expected
by the ore processing plant, and (iii) the overall minimization of the movement time/cost of
the shovel fleet. This work proposes an optimization methodology to generate a short-term
open-pit mine production schedule optimizing multiple hierarchical objectives. For the generation of mine schedules, we propose an optimization model based on mixed-integer linear
programming (MILP). This model considers the usual restrictions of mine sequencing and
also takes into account both time and cost of movement between phases of each shovel.
In order to optimize the multiple hierarchical short-term objectives, we apply the hierarchical and weighted sum methods (Grodzevich & Romanko, 2006; Nehring et al., 2018) in
the proposed optimization model. We verify this methodology in a real open-pit mine case
study. The remainder of this paper is organized as follows. Section 2 briefly reviews the existing literature related to short-term mine production scheduling in open-pit mines. Section 3
presents the proposed optimization model and explains the procedure to perform various
objective optimization using both hierarchical and weighted sum methods. In section 4, we
describe the open-pit mine case study conducted to generate short-term production schedules optimizing multiple objectives, applying both hierarchical and weighted sum methods.
Section 5 reports the results and discussion of the case study. Finally, section 6 presents the
conclusions of the work.
© 2019 Taylor & Francis Group, London, ISBN 978-0-367-33604-2
443
Short-term open-pit mine production scheduling with
hierarchical objectives
F. Manríquez, H. González & N. Morales
DELPHOS Mine Planning Laboratory, Department of Mining Engineering and Advanced Mining
Technology Center (AMTC), Universidad de Chile, Santiago, Chile
ABSTRACT: Short-term mine scheduling in open-pit mines consists of meeting the objectives defined by the long-term mine production schedule. Short-term scheduling in open-pit
mines has multiple hierarchical objectives to optimize. This work proposes an optimization
methodology to generate a short-term open-pit mine production schedule optimizing multiple hierarchical objectives. For the generation of mine schedules, we propose an optimization model based on mixed-integer linear programming. This model considers the usual
restrictions of mine sequencing and also takes into account both time and cost of movement
between phases of each shovel. In order to optimize the multiple hierarchical short-term
objectives, we apply the hierarchical and weighted sum methods in the proposed optimization model. We verify this methodology in a real open-pit mine case study. The results show
that both methods generate short-term mine schedules optimizing the different short-term
objectives.
1 INTRODUCTION
Short-term mine scheduling in open-pit mines consists of meeting the objectives defined
by the long-term mine production schedule. Short-term scheduling in open-pit mines has
multiple objectives to optimize. In some mine operations, these objectives are ranked in a
descending order which are: (i) the minimization of the deviation between the ore sent to the
ore processing plant and the ore processing capacity of the plant per period, (ii) the minimization of the deviation between the metal fines sent to the plant and the fines expected
by the ore processing plant, and (iii) the overall minimization of the movement time/cost of
the shovel fleet. This work proposes an optimization methodology to generate a short-term
open-pit mine production schedule optimizing multiple hierarchical objectives. For the generation of mine schedules, we propose an optimization model based on mixed-integer linear
programming (MILP). This model considers the usual restrictions of mine sequencing and
also takes into account both time and cost of movement between phases of each shovel.
In order to optimize the multiple hierarchical short-term objectives, we apply the hierarchical and weighted sum methods (Grodzevich & Romanko, 2006; Nehring et al., 2018) in
the proposed optimization model. We verify this methodology in a real open-pit mine case
study. The remainder of this paper is organized as follows. Section 2 briefly reviews the existing literature related to short-term mine production scheduling in open-pit mines. Section 3
presents the proposed optimization model and explains the procedure to perform various
objective optimization using both hierarchical and weighted sum methods. In section 4, we
describe the open-pit mine case study conducted to generate short-term production schedules optimizing multiple objectives, applying both hierarchical and weighted sum methods.
Section 5 reports the results and discussion of the case study. Finally, section 6 presents the
conclusions of the work.