EM - Escola de Minas
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/6
Notícias
A Escola de Minas de Ouro Preto foi fundada pelo cientista Claude Henri Gorceix e inaugurada em 12 de outubro de 1876.
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Resultados da Pesquisa
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 Ore-waste and ore type classification using portable XRF : a case study of an iron mine from the Quadrilátero Ferrífero, Brazil.(2020) Urbano, Emílio Evo Magro Corrêa; Costa, João Felipe Coimbra Leite; Graça, Leonardo Martins; Cipriano, Ricardo Augusto ScholzGrade control is a fundamental activity for Short-Term Mine Planning as it validates the ore-waste and ore type classification of mine faces. Geological mapping and quasi-mining sampling provide indispensable information for the Short-Term Mine Planning team to update block models and for grade control of the run-of-mine (ROM). However, laboratory turnaround can take too long and not be timely for operational needs, affecting mining efficiency. To propose a solution for this issue we tested the accuracy of portable X-Ray Fluorescence (XRF) for ore-waste and ore type classification according to iron and phosphorus grade. Thus, iron ore run-of-mine samples from the Quadrilátero Ferrífero were analyzed with the portable XRF as pressed pellets. As a result, the overall accuracy of ore-waste classification was above 92% for different cut-off grades. On the other hand, while ore type classification had a better accuracy without calibration factors for iron, the use of calibration factors significantly improved the accuracy of ore type classification for phosphorus. Therefore, despite the portable XRF presenting good accuracy for ore-waste and ore type classification, further developments are still necessary on automatic information processing systems and sample support validation so that this analytical tool can be used on a large scale by grade control teams. Finally, the combined use of portable XRF and other techniques, such as Hyperspectral Sensing or XRD, can be of great value for mine operations.Item Evaluation of the effects of user profile and interface characteristics on performance during robotic teleoperation.(2018) Fidêncio, Aline Xavier; Monteiro, Paulo Marcos de Barros; Freitas, Gustavo Medeiros; Monteiro, Paulo Marcos de Barros; Freitas, Gustavo Medeiros; Reis, Agnaldo José da Rocha; Pinto, Paulo RaimundoIn the mining industry, operator safety has always been a crucial point, and therefore demands attention. In addition, given the high investments made in the enterprise, the search for a consistent and e cient production process is also relevant. To increase productivity and safety, teleoperation techniques can be used to allow the operator to be removed from the risk areas and operate the equipment from a safe distance. The work presented in this master's thesis was developed at the Instituto Tecnológico Vale (ITV) as a part of a broader project that aims the development of a conceptual framework that enables the analysis and validation of the application of teleoperation techniques in mining equipment. These equipment could be either used for exploration, engineering or extraction. More speci cally, this framework will permit the analysis of relevant information for teleoperation. This work represents the initial step taken, which comprises the execution of proof-of-concept tests in laboratory using a robotic system. Di erent teleoperation interfaces schemes consisting of video and haptic devices are analyzed under di erent aspects and the user point of view is taken into account. The goal is to analyze the e ects of the force feedback and of di erent visual feedback during teleoperation and to evaluate which prede ned users characteristics can contribute to better performance during teleoperation. Experimental tests were performed using a commercial mobile robotic platform Seekur Jr and teleoperation interfaces consisting of the haptic devices Novint Falcon and Geomagic Touch. This platform can be programmed in such a way that it operates emulating a mining equipment. For practical application-oriented tests, di erent operations from a mining process can be used as application of study (e.g. explosive charging or excavators operations). For the purposes of this work, interfaces for the control of the robotic platform locomotion were analyzed. In order to evaluate the in uence of interface characteristics and users pro le on performance during teleoperation two experiments were conducted. The experiments consisted of guiding the robotic platform in a scenario containing obstacles, using the di erent interfaces. In this work, delays in communication during teleoperation were not addressed. Results show that the use of force feedback e ectively contributes for better performances in term of task execution time, number of collisions with obstacles and task completion in teleoperation activities. Moreover, additional visual information, such as the environment map, can also increase perception of obstacles.Item Uso turístico da mina subterránea brasileira de ouro de Passagem (MG).(2017) Miranda, José Fernando; Curi, AdilsonBrasil tuvo varios casos de cierre inadecuado de minas durante su historia. En las últimas décadas, sin embargo, los casos de restauración de las minas, incluyendo un nuevo uso del área, son frecuentes. La principal razón para ello ha sido una legislación más exigente y más actuante. Este artículo describe el caso de la restauración de la mina subterránea cerrada de Passagem en Mariana (MG) para su uso como una estructura de turismo histórico y de aventura. En este estudio de caso se contemplan seis áreas principales de impactos: Impacto en el ambiente físico, biológico y ecológico; impacto en los valores de uso alternativos del área; impacto en la calidad de vida; impacto en los valores culturales y sociales; impacto en el desarrollo económico y sostenible.Item Influence of soil granulometry on average body size in soil ant assemblages : implications for bioindication.(2017) Milanez, Cinthia Borges da Costa; Majer, Jonathan David; Castro, Paulo de Tarso Amorim; Ribeiro, Sérvio PontesSoil granulometric composition can impose constraints on ant species living in ground habitats, being an important factor in defining the habitat templet, which describes how certain animal life histories, including the trait of body size, can be selected. The ant fauna plays a central role in soil formation, and a vast literature describes such influence, but not the converse. Along with termites, worms and other invertebrates, these organisms promote the formation of channels, pores, and aggregates that influence gases and water moving through the soil profile. On the other hand, it is important to understand whether soil traits constrain insect colonization, so we here ask how soil traits can influence niche specificities, which seems to be a neglected ecological issue. A literature search using the key words ‘ants or Formicidae’ and ‘soil structure or pedogenesis’ revealed numerous references dealing with the influence of ants on soil, but not conversely. We here present a novel geomorphologic approach to habitat templets for two distinct riparian Neotropical ecosystems, based on the amalgamation of soil/sediment analysis with ecological processes and ant species biology. We found that predominance of fine grains favoured the preponderance of small ant species at a threshold of <5 mm in body length. Based on this, we propose the use of a quantitative, theoretically sound, statistical approach to bioindication.Item Assessing the impacts of mining activities on zooplankton functional diversity.(2016) Moreira, Francisco Wagner Araujo; Leite, Mariangela Garcia Praça; Fujaco, Maria Augusta Gonçalves; Mendonça, Fellipe Pinheiro Chagas; Campos, Larissa Paraguassú; Sant'Anna, Eneida Maria EskinaziMining activities generate countless environmental impacts, including heavy-metal contamination, sorting and increased turbidity. In aquatic ecosystems these impacts can drastically affect the initial links of the food chain, such as zooplankton. Methods: To evaluate how the different mining activities can influence the structure and functional diversity of zooplankton, we investigated the geochemical characteristics of the water and sediment in two small impoundments impacted by different mining activities (kaolin and iron extraction). We also explored zooplankton composition, species diversity and functional diversity (feeding guilds taxa). Results: As expected, the water and the sediment of both of the reservoirs showed high concentrations of trace elements, particularly Al, Ba, Fe, Mg, Mn, Sr and Zn. Zooplankton biomass and diversity were markedly reduced (< 12 μg.DW.L-1 and H’ < 1.5, respectively), and negatively correlated with turbidity and total suspended solids. Small microphages dominated the trophic composition of zooplankton, and an alternation of trophic guilds was not observed, since the dynamics of raptorial organisms was essentially linked to the temporal fluctuation of a single species of rotifer (Polyarthra cf. dolichoptera). Conclusions: In addition to changes in the aquatic habitat and zooplankton composition, the functional niches were also affected by the mining impacts. The use of the functional diversity analysis can emerge as a valuable approach to understand how zooplankton communities respond to drastic environmental changes.Item A Life Cycle Assessment study of iron ore mining.(2015) Ferreira, Hélio; Leite, Mariangela Garcia PraçaThis paper assessed the cradle-to-gate life cycle of an iron ore mining. The study was based on production data from an open pit mine located in the Iron Quadrangle/Brazil. The functional unit was defined as “one tonne of iron ore concentrate produced” and the data used were collected directly from the company's production reports covering the time of one year. The evaluation included the classification and characterization of life cycle impacts, not including normalization and weighting as well as sensitivity analysis of results. The evaluation of impacts used SimaPro-7, Ecoinvent 2.0, Eco indicator'99 and IPCC 2007. The results indicated that the use of grinding media in the processes is the main source of environmental impacts in the iron ore production chain, highlighting its contribution to life cycle impacts on human health and quality of ecosystems. Ore transportation by conveyor belts powered by electricity was more efficient in relation to the generation of impacts on the abiotic resources depletion and on climate changes than ore transportation by diesel trucks because the electricity generation matrix in Brazil has significant participation from hydroelectric plants.Item Seleção de caminhões rodoviários para mineração utilizando a metodologia de auxílio multicritério à decisão : estudo de caso: mineração de bauxita.(Programa de Pós-Graduação em Engenharia Mineral. Departamento de Engenharia de Minas, Escola de Minas, Universidade Federal de Ouro Preto., 2012) Sousa Junior, Wilson Trigueiro de; Cabral, Ivo EyerEm todos os empreendimentos minerários, um fator que merece estudos econômicos prévios são os custos de transporte relacionados ao empreendimento, sejam estes custos logísticos internos ou externos, acarretando grande peso no lucro líquido. Assim, se faz muito importante nas fases de aquisição ou substituição de frotas de transporte, estudos de viabilidade econômica para se determinar a melhor combinação de equipamentos de carga e transporte (interno/externo) que atendam às demandas de produção com um menor custo, avaliando as alternativas existentes para aquisição no mercado. O presente trabalho utilizou um estudo de caso de seleção de caminhões rodoviários para o transporte do ROM (run of mine) em uma mineradora de bauxita do Estado de Minas Gerais, utilizando-se da metodologia de auxílio multicritério à decisão (MCDA em inglês ou AMD em português). Durante o estudo de caso três questões chaves foram selecionadas, respondendo às principais incertezas para a aquisição de equipamentos: qual modelo comprar, qual a quantidade mínima a ser adquirida e por quanto tempo permanecer com o equipamento. Para responder a primeira pergunta percebeu-se que, no estudo de caso, a diferença financeira entre as alternativas avaliadas não justificava a aquisição de uma em relação à outra. Foi constatado que a resposta às duas últimas perguntas deve ser realizada com cálculos e análises quantitativas, considerando-se dados financeiros. Assim, fatores qualitativos deveriam ser considerados no processo de decisão. Partindo da premissa de igual poder de escolha das alternativas, a utilização do AMD possibilitou a quantificação de dados qualitativos no processo de tomada de decisão. Com esse propósito, foi criada uma metodologia capaz de ser adaptada para atender a novos processos de aquisição/substituição de equipamentos em empresas mineradoras, considerando a possibilidade de se utilizar e especificar fatores importantes e subjetivos durante o processo de decisão da seleção desses equipamentos.Item From the Whitehorse Mining Initiative towards sustainable mining : lessons learned.(2011) Fitzpatrick, Patricia; Fonseca, Alberto de Freitas Castro; McAllister, Mary LouiseMuch debate has taken place within t he mineral policy community about whether or not meaningful progress has been made towards more sustainable practices. This paper investigates t he changing approaches towards sustainable development undertaken by t he Mining Association of Canada (M AC) over a period of approximately 20 years. The analysis begins in the early 1990s when MAC initiated the Whitehorse Mining Initiative (WMI) and concludes in 2010 when the association was operating under a strategy entitled Towards Sustainable Mining (TSM). The goal is to consider the nature of the learning that has taken place towards sustainability within the mineral industry using the ca se of a leading national mining association. The investigation was undertaken through a literature review as well as key informant interviews with stake holders affected by the Canadian Mining Industry. Findings suggest that MAC’ s approach to su stainable development has shif ted from an ambitious and holistic partnership involving a range of stake holders to a focused, member-specific agenda that addresses a few performance issues. The transition to TSM was based on lessons learned through working with the WMI and subsequent efforts. It reflects broader corporate tendencies to address social and ecological issues through corporate social responsibility initiatives. The implications of these trends suggest that voluntary initiatives in and of themselves should not be expected to replace the comprehensive regulatory responsibilities historically provided by government.