Fa
  • Ph.D. (2017)

    Operations Research

    Economics and Business Devision , Colorado School of Mines, Golden, Colorado, USA

  • M.Sc. (2015)

    Mineral and Energy Economics

    Economics and Business Devision , Colorado School of Mines, Golden, Colorado, USA

  • M.Sc. (2006)

    Mining Engineering

    , Tarbiat Modares University, Tehran, Iran

  • B.Sc. (2003)

    Mining Engineering

    , Isfahan University of Technology, Tehran, Iran

  • Linear Programing
  • Integer Programming
  • Non-linear Progarmming
  • Open Pit Mine Planning
  • Econometrics

    Contact

    Curriculum Vitae (CV)

    Practical performance of an open pit mine scheduling model considering blending and stockpiling

    Mojtaba Rezakhah, Eduardo Moreno, Alexandra Newman
    Journal PaperComputers & Operations Research , 2019 February 8, {Pages }

    Abstract

    Open pit mine production scheduling (OPMPS) is a decision problem which seeks to maximize net present value (NPV) by determining the extraction time of each block of ore and/or waste in a deposit and the destination to which this block is sent, eg, a processing plant or waste dump. Spatial precedence constraints are imposed, as are resource capacities. Stockpiles can be used to maintain low-grade ore for future processing, to store extracted material until processing capacity is available, and/or to blend material based on single or multiple block characteristics (ie, metal grade and/or contaminant). We adapt an existing integer-linear program to an operational polymetallic (gold and copper) open pit mine, in which the stockpile is used to

    Open Pit Mine Scheduling Model Considering Blending and Stockpiling

    Mojtaba Rezakhah, Eduardo Moreno
    Conference PaperInternational Symposium on Mine Planning & Equipment Selection , 2019 December 2, {Pages 75-82 }

    Abstract

    Open pit mine production scheduling (OPMPS) is a decision problem which maximizes net present value (NPV) by determining the extraction time and destination of each block of ore and/or waste in a deposit. Stockpiles can be used to maintain low-grade ore for future processing, to store extracted material until processing capacity is available, or to blend material based on single or multiple block characteristics (i.e., metal grade and/or contaminant). We modify an existing integer-linear program to maximize NPV and provide a schedule and stockpiling strategy for an operational open pit mine, in which the stockpile is used to blend materials based on multiple block characteristics. We compare the schedule of with that produced by which do

    Open pit mine planning with degradation due to stockpiling

    Mojtaba Rezakhah, Alexandra Newman
    Journal PaperComputers & Operations Research , 2018 November 20, {Pages }

    Abstract

    The open pit mine production scheduling with stockpiling (OPMPS+S) problem decides when to extract each notional, three-dimensional block of ore and/or waste in a deposit. In addition, this problem determines whether to send each block to a processing plant, to a stockpile, or to a waste dump. The objective function maximizes net present value, subject to constraints such as precedence, and capacities for mining and processing. Because the material within the stockpile is exposed to the environment, time-dependent changes may occur in the material’s properties, which results in increased processing costs or, equivalently, a net loss of value.We extend a linear-integer mine-planning model that considers stockpiling to account for degradati

    Linear models for stockpiling in open-pit mine production scheduling problems

    Eduardo Moreno, Mojtaba Rezakhah, Alexandra Newman, Felipe Ferreira
    Journal PaperEuropean Journal of Operational Research , Volume 260 , Issue 1, 2017 July 1, {Pages 212-221 }

    Abstract

    The open pit mine production scheduling (OPMPS) problem seeks to determine when, if ever, to extract each notional, three-dimensional block of ore and/or waste in a deposit and what to do with each, e.g., send it to a particular processing plant or to the waste dump. This scheduling model maximizes net present value subject to spatial precedence constraints, and resource capacities. Certain mines use stockpiles for blending different grades of extracted material, storing excess until processing capacity is available, or keeping low-grade ore for possible future processing. Common models assume that material in these stockpiles, or “buckets,” is theoretically immediately mixed and becomes homogeneous.We consider stockpiles as part of our

    Open pit mine planning with stockpiling

    Mojtaba Rezakhah
    Journal Paper , 2017 January , {Pages }

    Abstract

    This dissertation consists of three papers; the first is published in European Journal of Operational Research, the second is nearing submission to it Optimization and Engineering, and the third is nearing submission to International Journal of Mining, Reclamation and Environment. These papers apply operations research techniques to open pit mine production scheduling with stockpiling (OPMPS+S). The first paper, "Linear Models for Stockpiling in Open-pit Mine Production Scheduling Problems," reviews existing models to solve OPMPS+S and shows that a nonlinear-integer model provides an exact solution but is intractable even for medium-size data sets. Then, we present an approximation to that nonlinear-integer model, solve the nonli

    Design of stable slopes for Songun copper mine

    M Monjezi, K Goshtasbi, M Rezakhah, TN Singh
    Journal PaperMining Technology , Volume 116 , Issue 3, 2007 September 1, {Pages 146-152 }

    Abstract

    Slope angle is a critical parameter in the design of open pit mines. With low slope angles stripping ratio is increased considerably, adversely affecting the economics. Steep slope angles may reduce safety and cause failure. Therefore, a compromise is necessary to optimise the slope angle. Methods to analyse the stability of open pit slopes include limit equilibrium methods, empirical methods, physical and numerical methods. In the present work the fast Lagrangian analysis of continua (FLAC) software package was applied to determine overall slope angles in different parts of the proposed Songun copper mine, Iran. Five vertical sections with a proper coverage of all parts of the mine were considered. Stability analysis was performed with a s

    Design of Stable Pit Slopes of Sungun Copper Mine

    M Monjezi, M Rezakhah
    Journal Paper , Volume 2 , Issue 3, 2007 January 1, {Pages 41-49 }

    Abstract

    Determination of slope angle is one of the most important parameters in open pit mine design. With low slope angles, stripping is considerably increased. On the other hand, selection of high slope angles may reduce safety and causes failure. Therefore, to prevent slope failure and high stripping, a compromise is necessary to select an optimum slope angle. There are several methods of analyzing the stability of open pit slopes such as limit equilibrium methods, empirical methods and numerical methods. In this paper, FLAC software has been applied to determine the overall slope angles in the different parts of Sungun copper mine. For analyzing the slope, five vertical sections with a proper coverage of all parts of the mine, were considered.

    A MATHEMATICAL EQUATION FOR DETERMINATION OF PIT SLOPE OF SONGUN COPPER MINE

    M MONJEZI, K GOSHTASBI, M REZAKHAH
    Journal Paper , Volume 24 , 2006 January , {Pages }

    Abstract

    Determination of slope angle is one of the important parameters in designing open pits. Selection of high slope angle may reduce safety and cause slope failure. On the other hand, with low slope angle, stripping ratio is increased considerably. Therefore, preventing failure and excessive stripping, a compromise is necessary to choose an optimum angle for pit slope. There are several methods for analyzing stability of open pit slopes such as limit equilibrium methods, physical modeling and numerical simulation. In this paper, a relative critical section of Songun copper mine in which geo-mechanical characteristics of constituents rocks are low, has been selected and analyzed with the help of numerical method (software FLAC). In the static lo

    DESIGN OF OPTIMUM OVERALL SLOPE OF SONGUN COPPER MINE

    M MONJEZI, MEHRDAD HEYDARI, M REZAKHAH, AMIR TORABI
    Journal Paper , Volume 1 , 2005 January , {Pages }

    Abstract

    Determination of slope angle is one of the important parameters in designing open pits. With low slope angle, stripping of waste is increased considerably. On the other hand, selection of high slope angle may reduce safety and cause slope failure. Therefore, preventing failure and over stripping, a compromise is necessary to choose an optimum angle for slope. There are several methods for analyzing stability of open pit slopes such as limit equilibrium methods and numerical methods. In this paper, software FLAC SLOPE has been utilized to analyze the most critical section of Sungun open pit mine. For the section having 28.5 degrees a safety factor of 1.41 has been computed.

    Linear Programming Approximations for Modeling Instant‑Mixing Stockpiles

    Eduardo Moreno, Felipe Ferreira, Marcos Goycoolea, Daniel Espinoza, Alexandra Newman, Mojtaba Rezakhah
    Journal Paper , 1 January , {Pages }

    Abstract

    Stockpiles are a crucial part of mine planning. However, they are often ignored in longterm planning due to the difficulty of correctly evaluating their impact in mine scheduling. This difficulty arises mainly because materials of different grades are mixed in a stockpile, and the final grade of the material leaving the stockpile is a complex non-linear function of the material inside the stockpile. In practice, computational software uses different (usually linear) approximations for estimating this grade, but it is not clear how good these approximations are. In this paper, we discuss different optimization models to approximate the real impact of a stockpile on long-term mine planning. We discuss the properties of these models and compar

    Artificial Neural Network and Firefly Algorithm for Estimation and Minimization of Ground Vibration Induced by Blasting in a Mine

    Parichehr Bayat, Masoud Monjezi, Mojtaba Rezakhah, Danial Jahed Armaghani
    Journal Paper , 1 January , {Pages }

    Abstract

    It is of a high importance to introduce intelligent systems for estimation and optimization of blasting-induced ground vibration because it is one the most unwanted phenomena of blasting and it can damage surrounding structures. Hence, in this paper, estimation and minimization of blast-induced peak particle velocity (PPV) were conducted in two separate phases, namely prediction and optimization. In the prediction phase, an artificial neural network (ANN) model was developed to forecast PPV using as model inputs burden, spacing, distance from blast face, and charge per delay. The results of prediction phase showed that the ANN model, with coefficient of determinations of 0.938 and 0.977 for training and testing stages, respectively, can pro

    Current Teaching

    • MS.c.

      Econometrics & Forecasting

    Teaching History

    • MS.c.

      Production Planning in Surface Mining

    • 2020
      Rahmani, Nargess
      Investigating the effect of transportation system in optimizing short-term production planning of open pit mines - a case study
    • 2021
      Poorgolmohammadi, Farideh
    • 2021
      Sabahi Garaghani, Mohammad
    • 2022
      Nazeri, Ali
      Data not found
      Data not found
    • Director, Kelardasht Quarry Mine
    • Postdoc Fellow, Colorado School of Mines
    • Visiting Scholar, Universidad Adolf Ibanez, Santiago, Chile
    • Board of Director Appointments

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