DEMIN - Departamento de Engenharia de Minas

URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/510

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2018 - 20203

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Autor: search.filters.author.Nader, Alizeibek SaleimenTem arquivos: Sim

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Agora exibindo 1 - 3 de 3
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    Analysis of the impacts of slope angle variation on slope stability and NPV via two different final pit definition techniques.
    (2020) Chaves, Leonardo Soares; Carvalho, Luiz Alberto de; Souza, Felipe Ribeiro; Nader, Alizeibek Saleimen; Arroyo Ortiz, Carlos Enrique; Torres, Vidal Félix Navarro; Câmara, Taís Renata; Napa Garcia, Gian Franco; Valadão, George Eduardo Sales
    The traditionally and widely used Lerchs-Grossmann algorithm presents well-known limitations that newer propositions attempt to overcome. The direct block schedule (DBS) methodology, which has gained relevance with computational advances, obtains the final pit as a natural result of production sequencing, different from Lerchs-Grossmann-based algorithms. This process flow applies constraints in the final pit definition stage attempting to provide a more realistic result and to minimize risks. Slope instability is a common and inherent risk to open pit mining and may affect the project's net present value (NPV). A study of the impacts of slope angle variations on safety indexes and final pit NPV provides an auxiliary tool for the overall slope angle definition process. This article presents a case study in which the effects of variations of the overall slope angle on the safety factor (SF) and project NPV were analyzed. A total of 25 pits were generated by each studied final pit definition methodology, and each pit had the sections with the varied slope angles analyzed in the stability assessment, resulting in a total of 150 slopes analyzed. A comparison between the results obtained by the two different methodologies implemented in commercial software is presented. The results show no relationship between the NPV and the overall slope angle using the DBS methodology. An analysis of the results for each geotechnical sector obtained by the traditional methodology was conducted and may contribute to the trade-off analysis between the best slope angle to achieve a reasonable SF and the maximum NPV.
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    Direct stockpile scheduling : mathematical formulation.
    (2018) Souza, Felipe Ribeiro; Chaves, Leonardo Soares; Burgarelli, Hudson Rodrigues; Nader, Alizeibek Saleimen; Arroyo Ortiz, Carlos Enrique; Alberto, Luiz
    In a mining context, production scheduling’s main objective is to determine the best mining sequence of blocks to achieve the largest net present value and to maximize ore reserve exploitation. Stockpiling and blending procedures may represent very helpful alternatives for mine planning to ensure the ore quality and amount required by the processing plant. In order to satisfy industrial requirements of grades and tones, reducing stockpile fluctuations may represent a very important tool especially for medium and short term mine planning. Classical linear programing has been widely used to model blending problems at the mining industry, however this formulation allows only one objective formulation. The current work describes a system based on goal programing able to reach blending constraints desired by short/medium term planning. The proposed formulation achieves the best schedule scenario, ensuring cost constrains are respected. Hence, this study aims to provide support for both short and long term mine planning.
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    Direct block scheduling under marketing uncertainties.
    (2018) Burgarelli, Hudson Rodrigues; Souza, Felipe Ribeiro; Nader, Alizeibek Saleimen; Torres, Vidal Félix Navarro; Câmara, Taís Renata; Arroyo Ortiz, Carlos Enrique; Galery, Roberto
    Mineral projects are composed of geological, operational and market uncertainties, and reducing these uncertainties is one of the objectives of engineering. Most surveys assess the impact of geological and operational uncertainties on the mining planning. The objective of this work is to study the impact of market uncertainty on the mineral activity. The influence of iron ore price simulation on mining sequencing will be evaluated. The price of iron ore has random behavior that is best represented by the Geometric Brownian Movement system. This study analyzed the historical series of iron ore in order to determine the percentage volatility and drift. Traditionally, a constant and deterministic price is used for the ore mined in all periods of a mineral project. The direct block scheduling methodology was adopted because it is able to apply the appropriate financial discount factor to the simulated probabilistic price. The proposed methodology was able to quantify the market uncertainty.