Este estudo apresenta, de forma sistemática, a importância da infraestrutura de mina a céu aberto, determinando as atividades principais dessa fase e os impactos e benefícios causados por alterações na forma de execução, medidos através de indicadores de produtividade e resultados financeiros. Algumas atividades principais como a reconfiguração das faces dos bancos de lavra pela aplicação comparativa de desempenho de trator de esteira e retroescavadeira; o estabelecimento de padrão para o dimensionamento das camadas estruturais e funcionais das estradas de mina; a mensuração dos benefícios da construção e manutenção das estradas, no desempenho dos caminhões e dos tratores de esteira, através de estudos de caso e demonstrar que a aplicação de técnicas adequadas modificam o resultado operacional. A metodologia utilizada aborda a relevância da infraestrutura e da frota de equipamentos auxiliares dentro do ciclo operacional, propondo uma aplicação correta e sistemática, baseada na demanda e nas atividades auxiliares que proporcionam condições operacionais para as atividades "que geram valor", suportando o cumprimento das metas estabelecidas no plano de produção. Os principais resultados obtidos vão desde a melhoria da segurança operacional, da imagem da empresa, do resultado financeiro, ao melhor aproveitamento dos recursos minerais, impactando diretamente a sustentabilidade do negócio. Através dos casos abordados neste trabalho, conclui-se que o desempenho da mineração a céu aberto é fortemente dependente do foco dado à infraestrutura de mina, ou seja: da qualidade das pistas, adequação das praças de carregamento, condição operacional de pilhas de estéril ou minério, drenagem superficial, dos métodos de trabalho e da disciplina operacional, gerando ganhos e/ou perdas que vão de unidades de porcentagem a várias vezes a capacidade do processo abordado. / This study presents, in a systematic way, the importance of the infrastructure in the open pit mining, determining the main activities of this operation and the impacts and benefits from changes implemented measured by operating productivity indicators and financial results. Some major activities such as the reconfiguration of the slope faces by the comparative performance of bulldozer and backhoe; the establishment of standards for the design of structural and functional layers of the mine haul roads; measure the benefits of the construction and maintenance of roads, the performance of trucks and bulldozers, through case studies show that the application of appropriate techniques can modify the operating result. The methodology addresses the importance of infrastructure and auxiliary equipment fleet in the operating cycle, proposing a correct and systematic application, based on demand and auxiliary activities that provide operating conditions for activities "that create value", supporting the achievement of the goals established in the production plan. The main results ranging from improved operational safety, company image, financial results, the best use of mineral resources, directly impacts on the business sustainability. Through the cases discussed in this work, it is concluded that the performance of the open pit mining is strongly dependent on the focus given to the mine infrastructure wich means, the quality of the tracks, adequacy of the loading spots, operating condition of waste dumps or ore bins, surface drainage, working methods and operational discipline, generating gains and/or losses ranging from small amounts to several times the capacity of the covered process.

Este estudo apresenta, de forma sistemática, a importância da infraestrutura de mina a céu aberto, determinando as atividades principais dessa fase e os impactos e benefícios causados por alterações na forma de execução, medidos através de indicadores de produtividade e resultados financeiros. Algumas atividades principais como a reconfiguração das faces dos bancos de lavra pela aplicação comparativa de desempenho de trator de esteira e retroescavadeira; o estabelecimento de padrão para o dimensionamento das camadas estruturais e funcionais das estradas de mina; a mensuração dos benefícios da construção e manutenção das estradas, no desempenho dos caminhões e dos tratores de esteira, através de estudos de caso e demonstrar que a aplicação de técnicas adequadas modificam o resultado operacional. A metodologia utilizada aborda a relevância da infraestrutura e da frota de equipamentos auxiliares dentro do ciclo operacional, propondo uma aplicação correta e sistemática, baseada na demanda e nas atividades auxiliares que proporcionam condições operacionais para as atividades "que geram valor", suportando o cumprimento das metas estabelecidas no plano de produção. Os principais resultados obtidos vão desde a melhoria da segurança operacional, da imagem da empresa, do resultado financeiro, ao melhor aproveitamento dos recursos minerais, impactando diretamente a sustentabilidade do negócio. Através dos casos abordados neste trabalho, conclui-se que o desempenho da mineração a céu aberto é fortemente dependente do foco dado à infraestrutura de mina, ou seja: da qualidade das pistas, adequação das praças de carregamento, condição operacional de pilhas de estéril ou minério, drenagem superficial, dos métodos de trabalho e da disciplina operacional, gerando ganhos e/ou perdas que vão de unidades de porcentagem a várias vezes a capacidade do processo abordado. / This study presents, in a systematic way, the importance of the infrastructure in the open pit mining, determining the main activities of this operation and the impacts and benefits from changes implemented measured by operating productivity indicators and financial results. Some major activities such as the reconfiguration of the slope faces by the comparative performance of bulldozer and backhoe; the establishment of standards for the design of structural and functional layers of the mine haul roads; measure the benefits of the construction and maintenance of roads, the performance of trucks and bulldozers, through case studies show that the application of appropriate techniques can modify the operating result. The methodology addresses the importance of infrastructure and auxiliary equipment fleet in the operating cycle, proposing a correct and systematic application, based on demand and auxiliary activities that provide operating conditions for activities "that create value", supporting the achievement of the goals established in the production plan. The main results ranging from improved operational safety, company image, financial results, the best use of mineral resources, directly impacts on the business sustainability. Through the cases discussed in this work, it is concluded that the performance of the open pit mining is strongly dependent on the focus given to the mine infrastructure wich means, the quality of the tracks, adequacy of the loading spots, operating condition of waste dumps or ore bins, surface drainage, working methods and operational discipline, generating gains and/or losses ranging from small amounts to several times the capacity of the covered process.

Ingeniero Civil de Minas / El objetivo del presente trabajo es medir el impacto que tiene la dilución en la planificación de minas cielo abierto, para cuerpos altamente estratificados y vetiformes. En la actualidad la industria minera ha alcanzado un punto donde el descubrimiento de nuevos yacimientos masivos tipo pórfido cuprífero se vuelve cada vez más rara. Por ello los yacimientos de vetas cobran cada vez mayor importancia en el negocio minero. Un desafío que presentan estos cuerpos es la incorporación de técnicas o practicas operacionales que permitan alcanzar una selectividad suficiente para volver rentable el proyecto, sin mencionar que en ciertos contextos geológicos las estructuras presentan contaminantes, por lo que incluso siendo rentable pueden existir problemas en etapas posteriores. Con este fin se debe tratar la dilución como un factor fundamental, tema que en la industria actual es poco estudiado. Para ello se cuenta con la siguiente metodología, mediante un estudio de un yacimiento de cobre modificado, que imita a uno autentico a escala real. Primero se lleva a cabo un estudio sobre los tipos de dilución, su impacto y formas de cuantificarla en la industria. Luego se generan escenarios con diferentes leyes medias en la roca caja, además de cuatro cambios de soporte, con el fin de verificar el impacto en un amplio espectro de casos. Se construye un indicador que evalúa la vecindad de cada bloque, estableciendo una categoría según el contacto existente para cada uno de los bloques del modelo. Después se calculan las proporciones de mineral en contacto con estéril, cuantificando así la cantidad de recursos susceptibles a diluirse. A continuación, se realiza la planificación a largo plazo, donde finalmente se recolectan los resultados de los casos propuestos y se analizan mediante indicadores técnicos y económicos claves. Se llega que, a medida que aumenta el tamaño de bloque, aumenta la categoría de mineral en contacto con estéril, reduciéndose así la cantidad de mineral sin riesgo de dilución y de la misma manera se reduce el estéril en contacto solo con estéril, aunque en menor proporción. Finalmente, aplicando restricciones de mezcla en la planificación, admitiendo un máximo de dilución permitido, se producen castigos al VAN del proyecto, llegando a un balance entre el riesgo de diluir el recurso y el valor del plan.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / Currently, in open-pit mining operations, the highest cost among all processes is that of transporting trucks, whether in fuel, roads, tires, or spare parts, among other factors. Therefore, this article proposes the use of the Six Sigma methodology of continuous improvement as a quality management tool to reduce the downtime of the truck fleet to obtain better productivity in operations. The results of the investigation in the case study allowed to visualize that with the election of an optimal fleet appropriate for the conditions given in a mining project, the values of productivity and efficiency improve considerably. This is reflected in a better use of the machinery and in the reduction of unproductive times.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / Presplitting is a controlled-blasting technique with applications in open-pit mines. The main purpose of this technique is to prevent and control overbreaks caused by excessive vibrations due to blasting. This technique is especially effective in controlling overbreaks because it provides a separation surface between the main blasting pattern and the walls of the final slopes. The drilling mesh and loading conditions in the drill are designed in this study by considering the uncontrollable variables of the rock mass as important factors. The proposed model for the presplitting optimization process helps to optimize controlled-blasting designs. The main idea of the proposal is to develop a model that includes the most relevant processes, as well as the most suitable parameters for an efficient design. Copyright 2019.

Magíster en Ciencias de la Ingeniería, Mención Matemáticas Aplicadas. Ingeniero Civil Matemático / Un problema presente en la planificación minera es el de identificar cuál es el volumen y ubicación de material que maximice la operación de extracción dando forma a una mina a cielo abierto. El estudio matemático de este problema ha sido analizado desde los años 60 s y lo usual es discretizar el terreno en forma de bloques, conociendo en cada bloque distintas características de él, como por ejemplo, sus coordenadas y su beneficio asociado. El problema anterior haciendo uso de la discretización por bloques, puede ser formulado como uno de optimización entera denominado Final Open Pit y cuando al problema anterior se le agrega una restricción de capacidad, se le denomina Capacitated Final Open Pit. Otro problema importante, es el de planificar la operación en periodos de extracción, buscando siempre maximizar el beneficio de esta. Su formulación como problema de optimización entera utilizando el modelo de bloques se le denomina Capacitated Dynamic Open Pit. Se piensa que los bloques que son solución de este problema están contenidos en la solución del Final Open Pit. Probar esta conjetura es uno de los principales enfoques de este trabajo, y la forma para lograrlo es a través de la demostración de ciertas propiedades que cumplen los pits. Además se analizan posibles extensiones de esta conjetura al problema capacitado. Varios han sido los esfuerzos por resolver numéricamente y de forma eficiente esta familia de problemas lo que ha llevado a buscar otras formulaciones de estos mismos. Es así como surge el trabajo de Alvarez et al de 2011, en el cual se plantean los problemas usando optimización en espacio de funciones. En esta tesis, bajo hipótesis de diferenciablidad, se hace un estudio del problema en $\mathbb{R}^2$ enfocándose en caracterizar a la densidad de ganancia en el borde del pit y se formulan dos duales para este problema. Trabajando siempre con la hipótesis de diferenciabilidad se discretiza el problema en dos y tres dimensiones obteniendo algunas pruebas numéricas en casos pequeños. Finalmente, se adapta esta nueva discretización al caso del modelo de bloques y se presentan algunos resultados numéricos de éste. / Este trabajo ha sido parcialmente financiado por FONDECYT 1130816

Simulations assuming open-pit mines and different cessation landscapes of open-pit mines with urbanization were performed with a non-hydrostatic meteorological model. The possible enhancement or counteracting of the atmospheric responses to these simultaneously occurring (= accumulated) land-use changes are examined applying a formula drived from the principle of superposition. Although accumulated land-use changes substantially affect the local water and energy fluxes and significantly influence cloud and precipitation microphysics, they do not necessarily provide more significant changes in these quantities than the change of different land-use types to only one land-use type (=single land-use changes). Where the atmospheric responses to accumulated land-use changes are enhanced or inhibited, depends on the thermal, dynamical and hydrologic characteristics of the undergoing accumulated land-use changes as well as on the land-use adjacent to the land-use conversion. In regions dominated by drier surfaces (e.g., agriculture), no enhancement or counteraction according to the principle of superposition could be detected in this study. / Simulationen mit einer Tagebaulandschaft sowie verschiedenen Tagebaufolgelandschaften inklusive Urbanisierung wurden mit einem nicht-hydrostatischen meteorologischen Modell durchgeführt. Eine mögliche Verstärkung oder Abschwächung der atmosphärischen Reaktion auf gleichzeitig auftretende (akkumulierte) Landnutzungsänderungen wird mittels einer auf dem Prinzip der Superposition erstellten Formel untersucht. Obgleich die akkumulierten Landnutzungsänderungen die lokalen Energie- und Wasserflüsse merklich sowie die Wolken und Niederschlagsmikrophysik signifikant beeinflussen, führen sie nicht notwendigerweise zu stärkeren Änderungen dieser Größen als einfache Landnutzungsänderungen. Wo sich akkumulierte Landnutzungsänderungen in ihrer Wirkung auf die Atmosphäre verstärken oder abschwächen, hängt davon ab, wie stark sich die dynamischen, hydrologischen und energetischen Eigenschaften der veränderten Landnutzung von der vorherigen und denen der Umgebung unterscheiden. In Regionen, die durch trockene Flächen charakterisiert sind (z.B. Ackerland), konnte in dieser Studie kein Verstärken oder Abschwächen im Sinne einer Abweichung vom Prinzip der Superposition festgestellt werden.

Rock blasting is one of the most dominating operations in open pit mining efficiency. As many downstream processes depend on the blast-induced fragmentation, an optimized blasting strategy can influence the total revenue of a mine to a large extent.Boliden Aitik mine in northern Sweden is one of the largest copper mines in Europe. The annual production of the mine is expected to reach 36 million tonnes of ore in 2014; so continuous efforts are being made to boost the production. Highly automated equipment and new processing plant, in addition to new crushers, have sufficient capacity to reach the production goals; the current obstacle in the process of production increase is a bottleneck in crushers caused by oversize boulders. Boulders require extra efforts for secondary blasting or hammer breakage and if entered the crushers, they cause downtimes. Therefore a more evenly distributed fragmentation with less oversize material can be advantageous. Furthermore, a better fragmentation can cause a reduction in energy costs by demanding less amounts of crushing energy.In order to achieve a more favorable fragmentation, two alternative blast designs in addition to a reference design were tested and the results were evaluated and compared to the current design in Aitik. A comparatively large bench was divided to three sections with three different drill plans, which led to different specific charges in each section. The sections were drilled in patterns of 6x9 m, 7x9 m and 7x10 m of burden and spacing; planned specific charges of the sections were 1.17 kg/m3, 1.02 kg/m3, and 0.91 kg/m3 respectively. Similar to the current drill plan in Aitik, the section with 7x9 m (1.02 kg/m3 specific charge) was used as the reference for results comparison. The drilling and charging processes were monitored carefully and the post-blast parameters were measured accordingly. Laser scanning was used to measure the swelling of the sections and two different methods of image analysis were utilized to evaluate the fragmentation of the rock for each section. Drilling log data (MWD) were analyzed to evaluate the hardness of the rock; energy consumption log of the crusher was also analyzed and all the data was collected in a single database. VBA (Visual Basic for Applications) programming language was embedded within data spreadsheets to correlate the mentioned data to the coordinates of the rock by means of Minestar logs, which include both timestamps and coordinates of all machinery e.g. shovels and trucks.The results of the test show significant improvements in fragmentation and oversize material percentage in the section with 6x9 m drill plan (1.17 kg/m3). The advantage of 6x9 m plan was confirmed by 52% higher swelling, 66% lower oversize material and 26% lower crushing energy compared to the reference section. The section with 7x10 m drill plan (0.91 kg/m3) also showed theoretically acceptable results; however, the deviations from reference were not as large as formerly mentioned section. The swelling had a decrease of 8% compared to the reference section and the percentage of oversize material and crushing energy were increased by 16% and 2% respectively.Presented results are based only on technical aspects and do not include the costs of drilling and charging. Thus, in order to evaluate the drill plans in practice an economical evaluation of the sections should be conducted. Also a confirmation test with more accurate geology explorations is recommended.Finally, upon the request of Boliden Mines, a short report on the usage of Air-decking technique in Aitik is enclosed as an appendix. The report includes a brief introduction to air-decking and discusses practical solutions to apply this technique in Aitik. / Validerat; 20121001 (anonymous)

Faculty of Engineering and Built Enviroment School of Mining Engineering 0315711f musakale@egoli.min.wits.ac.za / Rockfalls are a significant risk in open pit mines. Once movement of a rock perched on the top of a slope (bench) has been initiated, the most important factor controlling its fall trajectory is the geometry of the slope (bench). The best possible knowledge of rockfall trajectories and energies is important in order to determine accurate risk zoning and for the design and construction of adequate defence systems near the threatened areas. This study attempts to determine the influence of bench geometries, and the coefficient of restitution of rock, on rockfall behaviour. A study of literature was carried out to review previous studies and other relevant information on rockfalls and their analysis. The literature may be divided into two categories: experimental methods involving physical modelling, and computer models involving rockfall analyses using computers analysis methods. Rockfall computer simulation is considered to be applicable, quick to carry out and reproducible. The accuracy of the results depends on the knowledge of site conditions and slope geometry. The use of the Modified Ritchie criterion for the design of catch benches in open pit mines was also investigated. The assessment of bounce height, maximum run-out distance and kinetic energy achieved during the fall of rocks on the catch bench were the bases of the evaluation of the results obtained in this project. The computer program, Rocfall Version 4, was used for the purposes of the research. The following parameter variables were considered in the analyses: three types of rock; slopes with three stack configurations; four bench heights; and four bench face angles. The results show that, for all stack configurations and rock types, the maximum runout distance and maximum bounce height increase as functions of bench height at a specific bench face angle. A single bench configuration provides a maximum run-out distance of falling rocks larger than the value determined using the Modified Ritchie criterion for all rock types and bench face angles. Multiple bench stack configurations provide maximum run-out distances less than the value determined using the Modified Ritchie criterion only for the 90o bench face angle in all rock types; those with 60o, 70o and 80o bench face angle provide a larger maximum run-out distance. Therefore, the validity of the Modified Ritchie criterion for the design of catch bench widths in open pit mines with inclined benches must be questioned. According to Ritchie’s study (1963), rocks that fall in trajectory (free fall) seldom give high bounces after impact on a catch bench. This project shows that this finding is valid for rocks with low coefficients of normal restitution. Rocks with lower coefficients of normal restitution provide larger run-out distances with flatter bench face angles compared with rocks with higher coefficients. In contrast, rocks with higher coefficients provide larger run-out distances than those with lower coefficients for steeper angles. The consideration of the influence of geometry (shape) of falling rocks on rockfall behaviour showed that, for a flatter slope, as could logically be expected, the maximum run-out distance is greatest for rounder rocks and smallest for flatter slabby iv rocks. This is due to the fact that on a flatter slope, the mode of falling of rounder rocks is rolling down the slope. This mode provides essentially no resistance to motion, resulting in largest maximum run-out distance. In contrast, for long flat slabs, the mode of movement will be sliding, which results in a smaller maximum run-out distance. The maximum run-out distance as function of rock shape reduces as the normal coefficient of restitution increases. For all rock types, the maximum bounce height reduces as a function of the friction angle for flatter slopes. This is due to the fact that rocks are in contact with the slope during the rockfall. As the coefficient of normal restitution increases, an increase in the maximum bounce height results.

Esta dissertação apresenta uma revisão bibliográfica dos principais aspectos envolvidos nas operações de escavação de rochas com furos de grande diâmetro na mineração a céu aberto. O trabalho expõe o método de perfuração rotativa por ser o mais utilizado na execução desta operação unitária de lavra. Faz-se também um estudo dos principais agentes de desmonte que contribuem no emprego de furos de grande diâmetro na indústria da mineração, especialmente na explotação de minérios metálicos. São analisadas as propriedades do maciço rochoso, na determinação da carga específica e sua influência nos resultados da escavação de rochas por explosivos. É realizada ainda uma análise da metodologia utilizada para o dimensionamento do plano de fogo, baseando-se na inter-relação existente entre seus diversos elementos geométricos. Apresenta-se também a teoria de crateras como uma metodologia alternativa para dimensionamento de plano de fogo. Finalmente mostram-se os principais impactos ambientais decorrentes da detonação de explosivos na escavação de rochas. / This dissertation presents a bibliographical review of the main aspects involved in the open pit blasting operation using large diameter blastholes. The work displays the method of rotary drilling, being the most frequent used in the execution of this mining unitary operation. Here is presented a study of the main blasting agents that contribute to the increasing application of large diameter blastholes in the mining industry, especially in the field of metallic ores. The properties of the rock mass are analysed, in the determination of the powder factor and its influence on the results of rock excavation by explosives. An analysis of the methodology used for the determination a shot plan is carried out based on the existing interrelation between diverse geometric elements involved. The crater theory is also presented as an alternative methodology for the same purpose. Finally, the main environmental impacts caused by blasting in the rock excavation are discussed.