O presente trabalho propõe a concentração da bauxita presente em um rejeito fino gerado na usina de beneficiamento da Companhia Brasileira de Alumínio (CBA), agora denominada Votorantim Metais Alumínio, em Itamarati de Minas (MG), através da flotação reversa da sílica, sob a forma de quartzo. Como os minerais de ferro e titânio acompanham a bauxita, é necessário fazer separação magnética para eliminá-los do concentrado final. O concentrado de ferro e titânio pode ser utilizado como aditivo para fabricação de cimento portland. O rejeito de sílica pode ser utilizado como areia para construção civil ou na própria mina em manutenção de vias de acesso. Os experimentos sistemáticos em bancada foram realizados em célula de flotação mecânica, primeiramente, com minério de uma amostragem realizada em 2004. Determinadas as dosagens ótimas dos reagentes (coletor e depressor), partiu-se para a flotação com etapas cleaner e scavenger para definir o balanço de massas e verificar o comportamento do processo. Para validar as conclusões do trabalho experimental, foi feita nova amostragem na usina de beneficiamento de Itamarati de Minas, em julho de 2005, e, com este minério, o experimento de flotação com recirculação de produtos em um circuito em bancada composto por cinco etapas rougher, cleaner e scavenger. Partindo-se de uma alimentação nova com 11,6% de alumina aproveitável, chegou-se a um concentrado com teor de 52,6% no final do circuito, após a separação magnética, com recuperação em massa de 13,3% e recuperação de alumina aproveitável de 60,4%. / The present work proposes bauxite concentration using quartz flotation from a product so far considered a tailing, from the ore processing plant of Companhia Brasileira de Alumínio (CBA), now called Votorantim Metais Alumínio, at Itamarati de Minas (MG). A magnetic separation operation is also necessary to eliminate iron and titanium contaminants. Both products from this beneficiation process can have an industrial destination: iron and titanium concentrate can be used as a portland cement charge and the quartz can be used as construction sand in mine or in road maintenance. Systematic experiments were performed on bench cell froth flotation using the remaining ore sample taken in a 2004 campaign. The optimum collector and depressant dosages were found, followed by a flotation test with cleaner and scavenger that determined the mass balance and confirmed the process behavior. To validate these conclusions a fresh ore sample was taken in July 2005. A new simulation of the flotation circuit by locked cycle with five steps rougher, cleaner and scavenger in bench scale was done with this sample. From an 11,6% alumina feed, a 52% Al2O3 alumina concentrate was achieved, after magnetic separation. The mass recovery was 13,3% and the available alumina recovery was 60,4%

La presente investigación se titula “Propuesta de uso de equipo LHD a batería como alternativa competitiva frente al equipo diésel en el proceso de limpieza de labores subterráneas horizontales en una operación minera mecanizada”. Este estudio tiene como objetivo evaluar una propuesta de uso del equipo LHD a batería como alternativa competitiva frente al equipo diésel en el proceso de limpieza de labores subterráneas horizontales determinando los factores productivos, analizando la sostenibilidad ambiental y evaluando los costos operacionales relacionada a los equipos LHD diésel y batería. Asimismo, para la evaluación comparativa de estos equipos se realizó un análisis a través de un caso de estudio en una unidad minera de operación mecanizada, con similares características a la Unidad Minera Atacocha. Los equipos que serán utilizados para la evaluación, bajo las mismas condiciones de trabajo, son el LHD a batería (ST7), de la empresa Epiroc, y el LHD diésel (R 1300G), de la empresa Caterpillar; ambos con una capacidad de carga útil nominal de 6,800 kg (4.2 yd3). Los resultados obtenidos a través del caso de estudio se dieron en tres niveles: productivo, sostenible ambiental y económico. En el aspecto productivo, se determinó que el equipo LHD a batería en comparación con el equipo LHD a diésel, para una distancia de acarreo de 150 m, tiene un menor tiempo de ciclo de 8.23%, y un mayor rendimiento productivo de 8.98%. En relación a los indicadores de gestión, se determinó que los equipos LHD a batería posee una ventaja frente a los equipos diésel como en los indicadores de disponibilidad mecánica, utilización efectiva, MTBF y MTTR, obteniendo que en los tres primeros es mayor en 0.51%, 10.45%, 4.8%, respectivamente; por el lado del indicador de MTTR, con un resultado de 12.52% menor que el equipo diésel. En el aspecto de sostenibilidad ambiental, cuando se tiene al equipo diésel en funcionamiento se incrementan los niveles de gases en comparación a los equipos a batería en 76.63% en CO, 72.45% en CO2, 50% en NO2; asimismo, en la zona de trabajo del equipo diésel, se genera un incremento de temperatura de 19°C mientras que con el equipo a batería se tiene un incremento de 3.5°C. Finalmente, en el aspecto económico, se determinó que los equipos a diésel poseen un menor costo de posesión de 35.28 $/hr, un mayor costo operacional de 31.24 $/hr y un mayor costo total, incluyendo costo ventilación, de 1.63 $/hr a diferencia del equipo a batería. / This research is titled "Proposal for the use of battery-powered LHD equipment as a competitive alternative to diesel equipment in the cleaning process of horizontal underground workings in a mechanized mining operation." This study aims to evaluate a proposal for the use of battery-powered LHD equipment as a competitive alternative to diesel equipment in the cleaning process of horizontal underground workings, determining the productive factors, analyzing environmental sustainability and evaluating the operational costs related to LHD equipment. diesel and battery. Likewise, for the comparative evaluation of these equipment, an analysis was carried out through a case study in a mechanized mining unit, with similar characteristics to the Atacocha Mining Unit. The equipment that will be used for the evaluation, under the same working conditions, are the battery-powered LHD (ST7), from Epiroc, and the diesel LHD (R 1300G), from Caterpillar; both with a rated payload capacity of 6,800 kg (4.2 yd3). The results obtained through the case study occurred at three levels: productive, environmentally sustainable and economic. In the productive aspect, it was determined that the battery-powered LHD equipment compared to the diesel-powered LHD equipment, for a hauling distance of 150 m, has a shorter cycle time of 8.23%, and a higher productive performance of 8.98%. In relation to the management indicators, it was determined that battery-powered LHD equipment has an advantage over diesel equipment as in the indicators of mechanical availability, effective use, MTBF and MTTR, obtaining that in the first three it is greater by 0.51% , 10.45%, 4.8%, respectively; on the side of the MTTR indicator, with a result of 12.52% lower than the diesel equipment. In the aspect of environmental sustainability, when the diesel equipment is in operation, the levels of gases are increased compared to battery-powered equipment by 76.63% in CO, 72.45% in CO2, 50% in NO2; Likewise, in the work area of the diesel equipment, a temperature increase of 19 °C is generated, while with the battery-powered equipment there is an increase of 3.5 °C. Finally, in the economic aspect, it was determined that diesel equipment has a lower cost of ownership of 35.28 $/hr, a higher operating cost of 31.24 $ /hr and a higher total cost, including ventilation cost, of 1.63 $/hr unlike battery powered equipment. / Tesis