scholarly journals Stochastic Open-Pit Mine Production Scheduling: A Case Study of an Iron Deposit

Minerals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 585 ◽  
Author(s):  
Mohammad Maleki ◽  
Enrique Jélvez ◽  
Xavier Emery ◽  
Nelson Morales
Keyword(s):  
Production Scheduling ◽  
Iron Ore ◽  
Deterministic Model ◽  
Mine Planning ◽  
Open Pit ◽  
Iron Deposit ◽  
Planning Model ◽  
Sources Of Uncertainty ◽  
Block Models ◽  
Stochastic Mine Planning

Production planning decisions in the mining industry are affected by geological, geometallurgical, economic and operational information. However, the traditional approach to address this problem often relies on simplified models that ignore the variability and uncertainty of these parameters. In this paper, two main sources of uncertainty are combined to obtain multiple simulated block models in an iron ore deposit that include the rock type and seven quantitative variables (grades of Fe, SiO2, S, P and K, magnetic ratio and specific gravity). To assess the effect of integrating these two sources of uncertainty in mine planning decision, stochastic and deterministic production scheduling models are applied based on the simulated block models. The results show the capacity of the stochastic mine planning model to identify and minimize risks, obtaining valuable information in ore content or quality at early stages of the project, and improving decision-making with respect to the deterministic production scheduling. Numerically speaking, the stochastic mine planning model improves 6% expected cumulative discounted cash flow and generates 16% more iron ore than deterministic model.

scholarly journals Incorporation of Geometallurgical Attributes and Geological Uncertainty into Long-Term Open-Pit Mine Planning

Minerals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 108 ◽  
Author(s):  
Nelson Morales ◽  
Sebastián Seguel ◽  
Alejandro Cáceres ◽  
Enrique Jélvez ◽  
Maximiliano Alarcón
Keyword(s):  
Production Scheduling ◽  
Programming Model ◽  
Mineral Resources ◽  
Mineral Deposit ◽  
Open Pit Mine ◽  
Mine Planning ◽  
Open Pit ◽  
Operational Parameters ◽  
Financial Outcomes

Long-term open-pit mine planning is a critical stage of a mining project that seeks to establish the best strategy for extracting mineral resources, based on the assumption of several economic, geological and operational parameters. Conventionally, during this process it is common to use deterministic resource models to estimate in situ ore grades and to assume average values for geometallurgical variables. These assumptions cause risks that may negatively impact on the planned production and finally on the project value. This paper addresses the long-term planning of an open-pit mine considering (i) the incorporation of geometallurgical models given by equiprobable scenarios that allow for the assessing of the spatial variability and the uncertainty of the mineral deposit, and (ii) the use of stochastic integer programming model for risk analysis in direct block scheduling, considering the scenarios simultaneously. The methodology comprises two stages: pit optimization to generate initial ultimate pit limit per scenario and then to define a single ultimate pit based on reliability, and stochastic life-of-mine production scheduling to define block extraction sequences within the reliability ultimate pit to maximize the expected discounted value and minimize the total cost of production objective deviations. To evaluate the effect of the geometallurgical information, both stages consider different optimization strategies that depend on the economic model to be used and the type of processing constraints established in the scheduling. The results show that geometallurgical data with their associated uncertainties can change the decisions regarding pit limits and production schedule and, consequently, to impact the financial outcomes.

Risk Management Incorporated to Life-of-Mine Planning at Sossego Copper Mine, Carajás, Brazil

2014 ◽  
Vol 805 ◽  
pp. 263-271 ◽  
Author(s):  
Sandro Freitas ◽  
Benevides Aires ◽  
Giorgio de Tomi ◽  
Richardson Agra
Keyword(s):  
Decision Making ◽  
Production Scheduling ◽  
Real Life ◽  
Mine Planning ◽  
Open Pit ◽  
Copper Mine ◽  
Mining Sequence ◽  
Grade Uncertainty ◽  
The Impact ◽  
Production Plans

Open pit mine design and production scheduling deals with the quest for most profitable mining sequence over the life of a mine. The dynamics of mining ore and waste, and spatial grade uncertainty make predictions of the optimal mining sequence a challenging task. Valuation and related decision-making in surface mining require the assessment and management of orebody risk in the generation of a pit design and long term production scheduling. As the most profitable mining sequence over de life of a mine determines both economic outcome of a project and the technical plan to be followed from mine development to mine closure, the adverse effects of orebody risk on performance is critical and are documented in various studies. Ignoring such a consequential source of risk and uncertainty may lead to unrealistic production plans. This paper presented a set of procedures that enable mine planning engineers to carry out a series of analysis, which can be used to evaluate the sensitivity of incremental pit shells and pit designs to grade uncertainty. The results obtained from the analysis have shown to provide valuable information, which can be used to develop mining strategies that are risk resilient in relation to grade uncertainty. A real life application at Sossego copper mine ensure that such procedures are technically implementable, supporting decision-making as (a) in-fill drilling programs; (b) review of mining sequence; (c) identification of areas of upside potential and downside risk and (d) ore blending between mining areas in order to minimize the impact of high risk areas. The goal of this work is to provide an approach for clear risk analysis and management in mine planning cycle to various aspects of pit optimisation and design, resulting in more technically and economically sustainable life-of-mine production plans and mineral reserve depletion.

scholarly journals Integrated Parametric Graph Closure and Branch-and-Cut Algorithm for Open Pit Mine Scheduling under Uncertainty

Mining ◽  
2022 ◽  
Vol 2 (1) ◽  
pp. 32-51
Author(s):  
Devendra Joshi ◽  
Amol Paithankar ◽  
Snehamoy Chatterjee ◽  
Sk Md Equeenuddin
Keyword(s):  
Production Scheduling ◽  
Resource Constraints ◽  
Deterministic Model ◽  
Open Pit Mine ◽  
Branch And Cut ◽  
Open Pit ◽  
Computational Time ◽  
Scheduling Problems ◽  
Stochastic Production ◽  
Stochastic Production Scheduling

Open pit mine production scheduling is a computationally expensive large-scale mixed-integer linear programming problem. This research develops a computationally efficient algorithm to solve open pit production scheduling problems under uncertain geological parameters. The proposed solution approach for production scheduling is a two-stage process. The stochastic production scheduling problem is iteratively solved in the first stage after relaxing resource constraints using a parametric graph closure algorithm. Finally, the branch-and-cut algorithm is applied to respect the resource constraints, which might be violated during the first stage of the algorithm. Six small-scale production scheduling problems from iron and copper mines were used to validate the proposed stochastic production scheduling model. The results demonstrated that the proposed method could significantly improve the computational time with a reasonable optimality gap (the maximum gap is 4%). In addition, the proposed stochastic method is tested using industrial-scale copper data and compared with its deterministic model. The results show that the net present value for the stochastic model improved by 6% compared to the deterministic model.

scholarly journals A practical, long-term production scheduling model in open pit mines using integer linear programming

2020 ◽  
Vol 120 (12) ◽  
Author(s):  
J. Gholamnejad ◽  
R. Lotfian ◽  
S. Kasmaeeyazdi
Keyword(s):  
Linear Programming ◽  
Mathematical Programming ◽  
Integer Linear Programming ◽  
Production Scheduling ◽  
Mine Planning ◽  
Open Pit ◽  
Mixed Integer ◽  
Small Scale ◽  
Mining Equipment

SYNOPSIS Long-term production scheduling is a major step in open pit mine planning and design. It aims to maximize the net present value (NPV) of the cash flows from a mining project while satisfying all the operational constraints, such as grade blending, ore production, mining capacity, and pit slope during each scheduling period. Long-term plans not only determine the cash flow generated over the mine life, but are also the basis for medium- and short-term production scheduling. Mathematical programming methods, such as linear programming, mixed integer linear programming, dynamic programming, and graph theory, have shown to be well suited for optimization of mine production scheduling. However, the long-term plans generated by the mathematical formulations mostly create a scattered block extraction order on several benches that cannot be implemented in practice. The reason is the excessive movement of mining equipment between benches in a single scheduling period. In this paper, an alternative integer linear programming (ILP) formulation is presented for long-term production scheduling that reduced the number of active benches in any scheduling period. Numerical results of the proposed model on a small-scale open pit gold mine show a 34% reduction in the average number of working benches in a given scheduling period. Keywords: long-term production scheduling, mathematical programming, practical plans, equipment movements.

Production Scheduling for Strategic Open Pit Mine Planning: A Mixed-Integer Programming Approach

2020 ◽  
Vol 68 (5) ◽  
pp. 1425-1444 ◽  
Author(s):  
Orlando Rivera Letelier ◽  
Daniel Espinoza ◽  
Marcos Goycoolea ◽  
Eduardo Moreno ◽  
Gonzalo Muñoz
Keyword(s):  
Integer Programming ◽  
Production Scheduling ◽  
Large Scale ◽  
Mine Planning ◽  
Open Pit ◽  
Mixed Integer ◽  
Open Pit Mining ◽  
Programming Approach ◽  
Programming Methodology ◽  
Scale Optimization

Production scheduling is a large-scale optimization problem that must be solved on a yearly basis by every open pit mining project throughout the world. Surprisingly, however, this problem has only recently started to receive much attention from the operations research community. In this article, O. Rivera, D. Espinoza, M. Goycoolea, E. Moreno, and G. Muñoz propose an integer programming methodology for tackling this problem that combines new classes of preprocessing schemes, cutting planes, heuristics, and branching mechanisms. This methodology is shown to compute near-optimal solutions on a number of real-world planning problems whose complexity is beyond the capabilities of preexisting approaches.

Iron Ore Tailing as Addition to Partial Replacement of Portland Cement

2018 ◽  
Vol 930 ◽  
pp. 125-130 ◽  
Author(s):  
Luciano Fernandes de Magalhães ◽  
Isabella de Souza Morais ◽  
Luis Felipe dos Santos Lara ◽  
Domingos Sávio de Resende ◽  
Raquel Maria Rocha Oliveira Menezes ◽  
...  
Keyword(s):  
Portland Cement ◽  
Iron Ore ◽  
Mineral Exploration ◽  
Planetary Mill ◽  
Open Pit ◽  
Partial Replacement ◽  
Compression Tests ◽  
X Ray Diffraction ◽  
Open Pit Mines ◽  
Iron Ore Tailing

The manufacture of Portland cement used in the production of concrete emits large amounts of CO2into the atmosphere, contributing to the increase of the greenhouse effect. The environmental impact generated by the mineral exploration activity is a problem of easy verification, especially in open pit mines. The present work evaluated the possibility of using iron ore tailing as an addition to the partial replacement of the cement in mortars. The iron ore tailings were processed by drying in oven (48h at 105oC) and milling in a planetary mill (10min at 300RPM), obtaining medium grain size of 14,13 μm. For the characterization, laser granulometry, X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential thermal and thermogravimetric analysis (DTA / TGA) were performed. The sample is composed predominantly by quartz, hematite, goethite and gibbsite. After the characterization, the waste was used in the preparation of test specimens, with 10, 20 and 30% weight substitution of the cement. The composites were submitted to compression tests, with ages of 3, 7 and 28 days, using a strength rate of 0,25MPa/s. The mortars with 10, 20 and 30% of substitution presented resistance of 41.65, 36.26 and 31.64 MPa, being able to be characterized as category of Portland cement of resistance 40, 32 and 25 respectively. Considering the reduction of cement in the mortars produced, the results of compressive strength were relevant for the substitutions. The cements produced with the substitutions according to the Brazilian standards under the mechanical aspect can be classified as Portland cement.

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