DEMIN - Departamento de Engenharia de Minas
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/510
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Item The importance of the economic exploitation plan in the decision making process in mining.(2022) Almeida, Wendel Eduardo de; Curi, Adilson; Arroyo Ortiz, Carlos EnriqueIn general, investors evaluate several investment alternatives including, obviously, the possibility of money investment in the banking system. The mineral resource industry is just one of the several options of investment available in the financial market. To select this option, especially for the mining investments, investors require ever more projects with proven financial security and developed by renowned companies. The financial return or potential of the project must be significant to justify the risks inherent to the mining activities. To facilitate the financial analyses of mine projects, in this study is proposed a methodology based on an economic analysis of the Brazilian gold Berimbau mine through an Economic Exploitation Plan - EEP- where a sensitivity analysis of the project cash flow was performed and variations in the ore price, investments (CAPEX - capital expenditure) and operating costs (OPEX - operating expense) were applied. An orthodox scenario with an ore price (gold) of USD 900.00/oz was considered. The results, specific aspects and socioeconomic benefits have confirmed the project’s feasibility.Item Mine waste sequencing on an iron ore project.(2022) Curi, Adilson; Arroyo Ortiz, Carlos Enrique; Casimiro Huayhua, Jorhs EnriqueLos recursos minerales disponibles en nuestro planeta son finitos, aunque su potencial no sea conocido en su totalidad. El diseño de un proyecto minero, desde las actividades de exploración para conocer el depósito mineral, explotarlo y el cierre de una mina, puede influir la vida útil de la mina. El objetivo de este estudio es evaluar la forma de disposición selectiva de los residuos de una mina de hierro y su posible reutilización en el futuro, destacando su uso y posibles repercusiones en la extensión de su vida útil de una mina de hierro localizada en el Quadrilatero Ferrifero. Recursos y reservas han sido evaluados, así como las fases finales e intermediarias, la secuencia de minado y disposición de residuos. La metodología ha sido empleada en un depósito de hierro brasilero en operación. En donde se pretende demostrar la importancia de evaluar los materiales residuales a fin de prolongar la vida útil del yacimiento mineral.Item Effect of dynamic stress produced by rock blasting on the optimal dimensioning of room and pillars in horizontal layers.(2022) Cano Nunez, Alcides Eloy; Arroyo Ortiz, Carlos Enrique; Silva, José Margarida daAn optimal dimensioning of the room and pillars of the square or rectangular section is nding adequate transversal section support for the pillar; in that sense, all forces acting on the pillar must be evaluated. e pillar has its ends subjected to normal (σ) and shear stresses (τ). In addition, the pillar can also be subjected to dynamic stresses from the seismic waves generated by rock blasting. us, when calculating the dimensions of a mine pillar, the stresses imposed by seismic waves must be considered. e combination of lithostatic and dynamic stresses generated by blasting can a ect the pillar, generating regions, or areas that will exhibit the formation of cracks, microcracks, chipping, and other detrimental processes for its stability. In that regard, it is appropriate to assess the dynamic e ects of the energy delivered in each wave pulse so that these dynamic quantities can be included in the dimensioning of the pillars. is paper presents the physical and mathematical formulation describing the dimensioning issues of room and pillars and its solution using numerical modeling. e numerical modeling is performed using nonlinear mathematical programming and simulation with FLAC 3D (Fast Lagrangian Analysis of Continua in 3D). In this study, it was proven that the stress generated by the seismic wave represents a dynamic stress of nearly 5.5 MPa. 'Dimensioned pillars considering wave stresses allows it to recover an average 1.6% less when it is compared with pillars only under overlying rock mass'.Item Non-deterministic load and dump behaviour in mining haul trucks : a case of study.(2021) Barbosa, Rodrigo Correia; Arroyo Ortiz, Carlos Enrique; Curi, AdilsonComplex load and haul cycles in mining are composed of individual steps, whose times could be better described by a statistical distribution than by the average value. In order to evaluate how loading times and dumping times behave, this paper tested a large dataset of loading and dumping times measured at an open pit limestone mine in Brazil against the distributions most commonly used to model these variables, Log-normal and Normal; as well as Gamma, Logistic, Weibull and Exponential distributions. None of the tested distributions provided statistically significant adherence to the data, but it was possible to identify that for most equipment, Logistic and Normal distributions would produce less error on stochastic modelling then the other tested distributions.Item Impact of bulk density estimation in mine planning.(2021) Reis, Celso Henrique Miranda; Arroyo Ortiz, Carlos Enrique; Curi, Adilson; Zangrandi, Marcelo Henrique DamiãoThe incorporation of bulk density uncertainty for Mineral Resource and Mineral Reserves (MRMR) steps is of great importance for successful mine planning process. In practice, most mining projects use an average density value for each lithological type of the deposit. However, density determinations require special attention as they directly affect the conversion of volumes to tonnages and ore grades to metal contents. The objective of this study is to measure and minimize the risks associated with the MRMR stages, including the density variability in mine planning. Traditional interpolation techniques in geostatistics were used to represent density spatial distribution in a block model, similarly to those used for grade estimation. This approach was developed and applied at a Brazilian iron ore mine. The results indicate MRMR are underestimated if density uncertainty is not considered. Mine design changes were observed, including 5% impact on the Life-of-mine (LOM) and 2% in Net Present Value (NPV).Item Environmental and operational benefits through implementing a fleet management system in mining industry.(2020) Felsch Junior, Walter Schmidt; Arroyo Ortiz, Carlos Enrique; Curi, Adilson; Gonçalves, Douglas Ramos; Pinto, Alexandro AfonsoMining fleet management is fundamental to the transportation infrastructure in a mining nowadays. Several factors influence the success of a new system adoption, such as changes in the project design, operational maturity, direct leadership engagement, and senior management participation. To start with, the main objective of this study is to present the results obtained with the implementation of the Fleet Management System in a mining company located in the Southeast region of Brazil. In this study, the chronology of the implementation of the technology was presented, comparing the operational factors and environmental impacts to the operation results. As a result, there was a 23% increase in the transportation fleet performance, which led to a monthly potential reduction in the emission of 136 tons of greenhouse gases in the atmosphere because of the reduction of the transportation fleet required for ore movement. Furthermore, these gains may be enhanced over the years, expanding its possibilities with the use of new techniques and research.Item 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 SalesThe 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.Item Direct stockpile scheduling : mathematical formulation.(2018) Souza, Felipe Ribeiro; Chaves, Leonardo Soares; Burgarelli, Hudson Rodrigues; Nader, Alizeibek Saleimen; Arroyo Ortiz, Carlos Enrique; Alberto, LuizIn 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.Item Comparison between the application of the conventional mine planning and of the direct block scheduling on an open pit mine project.(2018) Campos, Pedro Henrique Alves; Cabral, Ivo Eyer; Arroyo Ortiz, Carlos Enrique; Morales, NelsonHistorically, since the 60's, traditional mine planning consists of several distinct stages: 1) Definition of the ultimate pit - the portion of the blocks that results in the greatest total value; 2) Pushback selection - based on the generation of nested pits, obtained with the change in the value of the ore price; 3) Long-term production scheduling. Although considered quite satisfactory, this methodology presents some flaws: The stages, even if considered individually optimal, may not be when put together. The opportunity cost is not considered and the cut-off is fixed. Due to the recent computational advances, a new technique has been growing and is more reliable: the direct block sequencing. In this methodology, the steps are consolidated into only one process, improving the economic results, reducing the total execution time and obtaining, in fact, an optimal planning. The aim of this work is to compare the results of the two planning methods applied in a database of a Brazilian iron ore mine and to show the real advantages and disadvantages of each one. To solve the direct block sequencing technique, Doppler was used, a tool developed by Delphos Mine Planning Laboratory, located at the University of Chile. The traditional methodology was executed through Whittle software. Lastly, a medium-term scheduling was performed using Deswik software.Item Classical and stochastic mine planning techniques, state of the art and trends.(2018) Torres, Vidal Félix Navarro; Nader, Beck; Arroyo Ortiz, Carlos Enrique; Souza, Felipe Ribeiro; Burgarelli, Hudson Rodrigues; Chaves, Leonardo Soares; Carvalho, Luiz Alberto de; Câmara, Taís Renata; Fernandes, Eunírio Zanetti; Galery, RobertoDetermination of the best possible ultimate pit for an open pit mine is a fundamental subject that has undergone a highly evolutionary process, reviewed in this study, since the correct choice carries substantial economic impact for the industry. The correct choice can be very beneficial for project analysis, whereas an incorrect choice has the potential to mask huge financial and economic future losses that could render a project unfeasible. The advent of computers in the 1960s allowed sophisticated analysis for the selection of the best ultimate pit determination, under specific modifying factors such as economic, social, environmental, and political, but only in deterministic situations, i.e., when the problem and variables for the ultimate pit determinations were considered deterministically and almost always based on average values. Techniques such as the Lerchs– Grossman algorithm and mixed-integer programming are among many standard tools now used by the mineral industry. Geological uncertainty and the associated risks as well as the need to consider the appropriate time to mine a block during a mine operation have a significant impact on the net present value of the resulting ultimate pits. Stochastic aspects embed a probabilistic component that varies in time and are now under intense investigation by researchers, who are creating algorithms that can be experimented with and tested in real mine situations. One can expect that once these algorithms demonstrate their efficiency and superior results, they will readily dominate the industry.