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http://hdl.handle.net/1843/31282
2024-03-28T22:34:01ZEstratégias eficazes para otimização da operação de mineração de bauxita em Juruti : análise de carregamento e transporte de minério e remoção de estéril
http://hdl.handle.net/1843/64885
Title: Estratégias eficazes para otimização da operação de mineração de bauxita em Juruti : análise de carregamento e transporte de minério e remoção de estéril
Abstract: This dissertation explores the challenges faced by the bauxite mining operation in Juruti, which has
been experiencing cost increases due to changes in the physical characteristics of the mine. The
study aims to seek viable alternatives to make the mining operation in Juruti more efficient and
sustainable. The study proposes methodologies for loading and transporting ore and removing waste
rock, with fleet sizing and cost modeling performed to compare them with the current operation. The
results demonstrate that the proposed methodologies significantly reduce mining costs in Juruti, with
a potential 65% reduction in operational costs. The study finds that there is a greater potential for cost
reduction in removing waste rock, with gains 150% larger than those of ore loading and transport.
The results suggest that the proposed alternatives present a feasible and effective solution to improve
the economic and environmental performance of mining in Juruti. Moreover, the results provide a
solid foundation for future discussions and developments of mining methodologies for tabular bauxite
deposits in the Amazon. The study concludes that the proposed methodologies can contribute to the
advancement of sustainable mining in the region, promoting greater economic and environmental
efficiency in mining activities.
Type: Dissertação2023-10-20T00:00:00ZLixiviação do pirocloro e finos de liga Fe-Nb para obtenção do óxido de nióbio de alto teor
http://hdl.handle.net/1843/62706
Title: Lixiviação do pirocloro e finos de liga Fe-Nb para obtenção do óxido de nióbio de alto teor
Abstract: The present work aimed to develop and propose at least one route for producing niobium
oxide of purity above 98.5%, through the leaching of impurities contained in the
pyrochlore concentrate and/or niobium leaching from Fe-Nb alloy fines. Two processing
routes were evaluated, being one of these routes for the pyrochlore concentrate the
proposed adaptation presented in the literature for a tantalite-columbite concentrate and
the other route (for Fe-Nb alloy fines) based on studies of the thermodynamic behavior
of niobium in hydrometallurgical processes and corrosion studies of the Fe-Nb alloy.
The route for the pyrochlore concentrate presented problems due to the formation of a
cohesive and resistant aggregate that reduced the surface area of contact and influenced
the alkaline leaching stage, hindering an efficient removal of the silicon and magnesium
contaminants. The total content of those elements overpassed 2%, that dificults to obtain
a product with 98,5% of Nb2O5. The study of this route requires na additional step of
cominuttion that was not carried out in the present study due to dproblems during the
pandemic of Covid_19.
It was prioritized the route for the Fe-Nb alloy fines that proved to be promising in the
formation of niobium compounds (potassium niobate, niobium acid and the final product
niobium oxide), had an acceptable yield and reached the quality target with a 98.5%
niobium oxide content.
Type: Dissertação2022-03-31T00:00:00ZO teor de corte como um output do planejamento estratégico para otimizar a geração de valor. Um estudo de caso
http://hdl.handle.net/1843/60027
Title: O teor de corte como um output do planejamento estratégico para otimizar a geração de valor. Um estudo de caso
Abstract: The cut-off grade, although being usually considered to be just another trivial step in the process of strategic planning in a mine, is an element of enormous importance when looking into a real operation or a mine project under a value generation or maximization of value generation point of view, because it carries in itself the power of classifying a volume of rock as ore or waste. Traditionally, from a series of cost parameters and assumptions cut-off grades are estimated or modelled and such grades are then used to delineate orebodies for which designs, and extraction sequences are developed considering mining, processing, and productivity constraints. Through this classic approach, the cut-off grade is part of a set of entries or inputs that culminate in the strategic plan. This work defends the idea that the cut-off level should be treated as an output factor of the strategic planning and as such it is under the control of the company in the definition of its corporate strategy. In order to support the idea, it proposes a case study using real operation data in which it compares the generation of value using the traditional approach – calculated by the method of Net Present Value (NPV) by discounted cash flows – with the generation of value when using the optimization of cut-off value to maximize the NPV.
Type: Dissertação2023-07-13T00:00:00ZProposição de metodologia de reconciliação de lavra para fábricas de cimento Portland
http://hdl.handle.net/1843/59610
Title: Proposição de metodologia de reconciliação de lavra para fábricas de cimento Portland
Abstract: Mined ores are the main raw material on the mining value chain and are studied and modelled through geological survey data. The uncertainties regarding ore tonnage and grade on short-term operation remain, no matter how good the geological models are. Deviations on production process can propagate with harmful consequences to subsequent activities on the value chain, reaching the final product, while harming the economic and socio-environmental performance of the mining companies. Performing the mine reconciliation is a way to use the data generated along the value chain to check the model and improve it. Mine reconciliation is a geometallurgical method of gathering data of production along the mining and plant process and comparing it at different points, to check the model, and can also be used to proactively detect problems like mining dilution or bad sampling practices. Although it is more common in metal mining, it is being shown that applications of mine reconciliation on industrial minerals sector are possible. This study intends to analyze the mining value chain of Portland cement: limestone and clay mining and its processing into clinker. The similarities and differences between this specific sector and metal mining are discussed, and an adapted methodology to reconcile mining operations on the cement industry is proposed. Afterwards, two case studies are carried out in operating cement plants, to test the proposed methodology and to evaluate the future potential of its practice, as well as the benefits generated and its scope of application. To have increasingly better predictive models, it is important to integrate the primary activities of the mining value chain. Even though geological uncertainties cannot be eliminated, the mine reconciliation is indeed an important step towards this end.
Type: Dissertação2022-07-27T00:00:00Z