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 Diagnosis of the production cycle in the small shaft sinking.(2022) Luz, José Aurélio Medeiros da; Silva, José Margarida da; Neuppmann, Pedro HenriqueShaft sinking is a classic activity in underground mines. In shafts with small cross-section or in mines with low mechanization indices it is common to use hand pneumatic drills and blasting by explosive gelatin in cartridges, employing natural draft or flexible ducts with axial fans for gases and fumes exhaustion, muck removal by hand shoveling into hoistable dumping buckets. System of this type has been studied here, consisting of a rectangular cross- section shaft (3.7 m x 2.0 m), with final depth of 94 m, excavated in order to obtain samples for a pilot-scale mineral processing testwork, before the open pit mine’s industrial startup. The shaft had a concrete collar and its walls were supported by wooden sets spaced 1.5 m and 25 mm thick wooden planks as liners. This shaft has been excavated in schist rocks belonging to the metamorphosed hydrothermal deposit of copper and gold located in Chapada (municipality of Mara Rosa, Brazil). Daily production worksheets covering one month campaign were statistically analyzed, encompassing the entire cycle of mining operations, namely drilling, charging and blasting, fumes exhaustion, mucking, wall and face trimming and scaling, and assemblage of support system. Operation downtimes were also quantified. Statistical analysis of productivity indices allowed the detection of critical points of the operation and the establishment reference for similar mining operations.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 Specific surface area of polydispersions as a function of size distribution sharpness.(2020) Lopes, Paulo Filipe Trindade; Luz, José Aurélio Medeiros da; Milhomem, Felipe de OrquizaKnowledge of particulate system properties is very important in various industrial instances and the possibility of fast predicting the behavior of such systems is an important control tool. The specifi c surface area of simulated particulate systems was studied as a function of the sharpness parameter of the size distribution of the Gates– Gaudin-Schumann, Gaudin–Meloy and Rosin–Rammler equations. The results showed good statistical adherence, especially the Rosin–Rammler equation, in situations where it is the best descriptor of particle size distribution.