Dissertations / Theses on the topic 'Open pit mine planning'

A fundamental problem in open pit mine planning is that of determining the optimum ultimate pit limits of the mine. These limits are that pit contour which is the result of extracting a volume of material which maximizes the difference between the value of extracted ore and the total extraction cost of ore and waste whilst satisfying certain practical operational requirements, such as. safe wall slopes. The determination of the optimum pit contour provides information which is essential in the evaluation of the economic potential of the mineral deposit.A number of optimization techniques have been proposed for determining the optimum pit contour. Of these techniques, those based on graph theory, linear programming and dynamic programming are mathematically rigorous, but only those based on graph theory are more suited to solving the three-dimensional problem. Unfortunately, direct application of these techniques to large ore- bodies may cause considerable difficulties because of the exceptionally high demand on computer storage and time requirements. Indeed, 25 years of research effort has not satisfactorily resolved these computational problems.A major contribution of the work presented in this thesis is the successful implementation of a system of techniques to solve the graph theoretic model, particularly when applied to large ore- bodies. A measure of this success is the fact that pits, as much as seven times larger may be designed with a given amount of computer storage, at a fraction of the time required by current software packages. The solution strategy presented involves the application of a modified Dinics Maximum Flow algorithm, together with an efficient data reducing technique. Computational results of these techniques applied on data from gold producing mines in Western Australia are used to demonstrate the success of this strategy.The relationships between the rigorous pit optimization techniques are also considered in this work. In particular, the Lerchs-Grossman graph-theoret ic method is shown to be stepwise equivalent to a modified version of the Dual-Simplex Linear Programming technique and not as efficient as the Network Flow method.

A fundamental problem in open pit mine planning is that of determining the optimum ultimate pit limits of the mine. These limits are that pit contour which is the result of extracting a volume of material which maximizes the difference between the value of extracted ore and the total extraction cost of ore and waste whilst satisfying certain practical operational requirements, such as. safe wall slopes. The determination of the optimum pit contour provides information which is essential in the evaluation of the economic potential of the mineral deposit.A number of optimization techniques have been proposed for determining the optimum pit contour. Of these techniques, those based on graph theory, linear programming and dynamic programming are mathematically rigorous, but only those based on graph theory are more suited to solving the three-dimensional problem. Unfortunately, direct application of these techniques to large ore- bodies may cause considerable difficulties because of the exceptionally high demand on computer storage and time requirements. Indeed, 25 years of research effort has not satisfactorily resolved these computational problems.A major contribution of the work presented in this thesis is the successful implementation of a system of techniques to solve the graph theoretic model, particularly when applied to large ore- bodies. A measure of this success is the fact that pits, as much as seven times larger may be designed with a given amount of computer storage, at a fraction of the time required by current software packages. The solution strategy presented involves the application of a modified Dinics Maximum Flow algorithm, together with an efficient data reducing technique. Computational results of these techniques applied on data from gold producing mines in Western Australia are used to demonstrate the success of this strategy.The relationships ++
between the rigorous pit optimization techniques are also considered in this work. In particular, the Lerchs-Grossman graph-theoret ic method is shown to be stepwise equivalent to a modified version of the Dual-Simplex Linear Programming technique and not as efficient as the Network Flow method.

Modern large-scale open pit mines move hundreds of thousands of tonnes of material daily, from the loading sources to the destination zones, whether these are massive mine dumps or, to a lesser extent, to the grinding mills. Mine dumps can be classified as leach or waste dumps, depending upon their economic viability to be processed in-place, a condition that has experienced great progress in the last decades and has reconfigured the open pit haulage network with an increase in the number of dumps. Therefore, new methods for dump design optimization are of the highest priority in mine planning management. This paper presents a methodology to model and optimize the design of a dump by minimizing the total haulage costs. The location and design of these dumps will be given mainly by the geological characteristics of the mineral, tonnage delivered, topographical conditions, infrastructure capital and transportation costs. Spatial and physical design possibilities, in addition, provide a set of parameters of mathematical and economic relationship that creates opportunities for modelling and thus facilitates the measurement and optimization of ultimate dump designs. The proposed methodology consists of: (1) Formulation of a dump model based on a system of equations relying on multiple relevant parameters; (2) Solves by minimizing the total cost using linear programming and determines a "preliminary" dump design; (3) Through a series of iterations, changes the "preliminary" footprint by projecting it to the topography and creates the ultimate dump design. Finally, an application for a waste rock dump illustrates this methodology.

A graph theory oriented algorithm for optimal ultimate pit limit design is developed. Mathematical proofs of optimality and convergence are given. The algorithm works on a 3-D block mine model and formulates the model into a directed graph consisting many trees. The vertices in the graph are identified with the blocks in the model and the imposed arcs in the graph represent pit slope constraints. The formation of each directed tree is based more on the ore-waste support concept than geometric constraints alone. The algorithm efficiently handles the joint support and re-allocation problems. The theoretical proof shows that the new algorithm is consistently faster than the well known Lerchs-Grossmann's (LG) algorithm, which is the only algorithm developed in the past one-quarter century capable of producing a true optimum pit limit. The case study results show that the new algorithm is able to generate the optimal ultimate pit limit for a model with 80 columns x 80 rows x 40 levels on an IBM PC AT 80286 microcomputer in 115 minutes. The indirect comparison was made between the results of the new algorithm and the results obtained by P. Huttagosol (1988, 1989) using the LG algorithm. P. Huttagosol optimized a smaller mine model than the one optimized by the new algorithm in 535 minutes of VAX8600 CPU time. The comparison between 535 minutes of VAX8600 CPU time for a smaller model with 115 minutes PC AT processing time for a bigger model clearly indicates that the new algorithm is significantly faster than the LG algorithm. This study also investigates both proposed mathematical optimization approaches and the popular trial and error "pushback" approach to long range mine planning. Both the theoretical analysis and numerical examples demonstrate it is impossible to obtain the optimal solution to mine production scheduling by the approach combining the Lagrangian relaxation with the ultimate pit limit algorithm. The non-convergence due to redundant optimal solutions and the non-convergence due to the requirement of advanced stripping are identified with the proposed approach. The investigation clarifies the long-time misunderstood concept and proves the impossibility of such a research direction itself. Finally, some problem solving techniques which play important roles in the computerized mine planning and grade control are developed and discussed. Specifically, they are: (1) point-in-polygon algorithm, (2) polygon area algorithm, (3) polygon clipping algorithm, (4) blast hole data collection, validation and database maintenance, and (5) the interactive graphics ore-waste delineation.

The mine production schedule defines the sequence of extraction of selected mine units over the life of the mine, and consequentially establishes the ore supply and total material movement. This sequence should be optimized so as to maximize the overall discounted value of the project. Conventional schedule approaches are unable to incorporate grade uncertainty into the scheduling problem formulation and may lead to serious deviations from forecasted production targets. Stochastic mine production schedulers are considered to obtain more robust mine production schedule solutions.
The application of stochastic approaches to the mine production schedule problem is recent and additional testing is required to better understand these tools and to define the value of a stochastic solution as compared to the conventional result. Two stochastic schedulers are tested in a low-grade variability copper deposit, optimization parameters are discussed and their results compared with a conventional schedule.
The first method uses a stochastic combinatorial optimization approach based on simulated annealing to address the mine production schedule problem. The method aims for maximization of the net present value (NPV) of the project and minimization of deviations from the production targets. These objectives are attained by incorporating grade uncertainty into the mine production schedule problem formulation. The second method formulates the problem as a stochastic integer programming problem, in which the objective is the maximization of the projects' NPV and the minimization of production targets deviations. The model can also manage how the risk of deviating from the targets is distributed between production periods.
Both stochastic approaches were tested in a low-grade variability copper deposit. In both case studies, the value of a stochastic solution is demonstrated to be higher than the conventional one. This fact demonstrated the misleading results that a conventional schedule may produce and shows the importance of not ignoring the presence of uncertainty when defining the mine production schedule for a project.

Magíster en Minería. Ingeniero Civil de Minas
La geomecánica y planificación minera son áreas de la minería a cielo abierto íntimamente relacionadas, ya que las restricciones geomecánicas limitan al diseño minero y, así, los planes mineros factibles. El diseño y los planes mineros han de empujar los límites de lo que la geomecánica permite, para asegurar operaciones mineras competitivas y mantener un nivel de riesgo al personal y operaciones aceptable. Luego, se requiere del monitoreo geotécnico para adquirir datos de calidad que permitan un diseño minero de alto nivel. Sin embargo, la relación entre geomecánica y planificación minera no se extiende al diseño e implementación de programas de monitoreo. En general, los programas de monitoreo de deformaciones superficiales son diseñados con posterioridad al inicio de la operación del rajo y cuando se han identificado signos de inestabilidad en la superficie de los taludes. El monitoreo de deformaciones del subsuelo permite alertar sobre fallas en desarrollo semanas antes de que estas se hagan notar en superficie. Luego, se debería diseñar campañas de monitoreo de deformaciones del subsuelo durante el proceso de planificación minera, considerando el diseño minero en la instalación de instrumentos geotécnicos previo a la construcción de la mina. Lo que permitiría registrar el proceso de relajación del macizo a medida que la construcción progresa y adquirir datos más exhaustivos del comportamiento del macizo rocoso (antes que con monitoreo superficial), con el fin de optimizar el diseño de taludes futuros y adoptar medidas correctivas para evitar fallas. En esta tesis, fueron diseñadas una serie de campañas de monitoreo de deformaciones del subsuelo usando In-Place Inclinometers, ShapeAccelArrays y Networked Smart Markers (NSMs) como equipos de monitoreo. Las opciones fueron aplicadas a una mina teórica desarrollada como parte de la tesis y comparadas en términos de costos, cantidad y calidad de los datos recopilados. Los resultados indican a la opción de NSMs cada 2[m] como la más eficiente en cuanto a costos ya que: (1) presenta el menor costo por unidad de datos adquiridos (US$57.21) y (2) 5 veces mayor vida útil, lo que permitiría obtener el doble de datos que la siguiente mejor opción, (3) se financia con un aumento de 2° en el ángulo de talud y (4) aumenta el VAN del proyecto en 3.2%.
Open pit geomechanics and mine planning are two closely related areas in the development of an open pit mine since geotechnical constrains limit the possible mine designs and, thus, the feasible mine plans. Mine designs and plans have to push the limits of what rock mass geomechanics allow to assure competitive mine operations, while maintaining acceptable levels of risk to operations and personnel. Therefore, geotechnical monitoring programs are required to acquire good quality data to be used as input for mine design. However, the relation between geomechanics and mine planning does not extend to monitoring programs design and implementation. Generally, surface deformation monitoring programs are designed after the project is in operation and signs of slope instability have been identified on the surface. Subsurface deformation monitoring can alert about developing failures weeks before any sign of instability is noted on the surface. Therefore, subsurface deformation monitoring campaigns should be designed along the mine planning process and considering the mine s design to install geotechnical instrumentation prior to the construction of the slopes. This methodology would allow to register the rock mass relaxation process as construction progresses and to acquire more comprehensive data about rock mass behaviour, in advanced of surface monitoring, towards future slope design optimization and adoption of remedial measurements to avoid failure. In this thesis, a series of subsurface deformation monitoring campaign were designed using In-Place Inclinometers, ShapeAccelArrays and Networked Smart Markers as monitoring devices. All options were applied to a theoretical open pit developed as part of this work. The campaigns were compared in terms of cost, quantity and quality of gathered data. The results showed that the campaign using NSMs installed every 2 meters was the most cost-efficient option as it represented: (1) the lowest cost per unit of gathered data (US$57.21), (2) five times longer lifespan, which allowed to gather twofold the amount of data compared with the next best option, (3) be financing of the campaign through steepening of the slopes by 2° and (4) increase in project s original NPV by 3.2%.

Com o passar dos anos a sociedade tem se tornado gradativamente mais dependente de recursos minerais para o seu funcionamento e para o desenvolvimento de produtos. A maior parte das coisas que cercam o homem necessita de alguma espécie de bem mineral como matéria prima para sua fabricação. Por isso, cada vez mais, a mineração tem sido objeto de estudos, buscando aprimoramento e desenvolvimento nos métodos de extração de minérios. Existem duas formas utilizadas para a extração de bens minerais, uma por uso de métodos de lavra a céu aberto (OP) e outra através da aplicação de métodos para lavra subterrânea (UG). A definição de qual método deve ser aplicado em cada caso depende de diversos fatores, como profundidade e geometria do corpo mineral, competência da rocha portadora do minério e da rocha encaixante, entre outros, mas ao final, aspectos econômicos predominam para a definição da viabilidade de cada um dos possíveis métodos. Porém, existem casos em que a melhor escolha para minerar o depósito não se dá por umas dessas duas opções, e sim, pela combinação de ambas, ou seja, a aplicação da lavra a céu aberto seguida da extração dos recursos remanescentes por lavra subterrânea. A grande dificuldade, nestes casos, é definir qual o momento ideal para a transição de método, de maneira que os resultados do projeto integrado sejam otimizados e que um método não inviabilize o outro. Para isso é necessário analisar as duas opções de lavra individualmente, lavrando somente a céu aberto e lavrando somente por métodos subterrâneos, além de analisar-se a viabilidade do projeto através da combinação dos dois métodos, comparando as opções técnica e economicamente e selecionando a que apresente a melhor resposta ao final, para então tomar-se a decisão de qual alternativa de projeto é o mais indicado para cada caso.
Over the years, the society has become progressively dependent on mineral resources for its operation and for development of products. The majority of the things that surround the men needs some kind of mineral material as raw material for its manufacture. Therefore, increasingly, mining has been studied aiming to improve and develop methods of mineral extraction. There are two ways that are utilized to mineral extraction, one by open pit methods (OP) e another by application of underground methods (UG). The definition of which one should be applied in each case depends on many factors, such as depth and geometry of the mineral body, strength of the mineralized and bounding rock, among others, but at the end, economic aspects are predominant for the definition of viability of the methods. However, there are some cases where the best choice to mine the deposit is not one of these options, but the combination of both methods, it means, the application of open pit mining followed by extraction of remaining resources by underground mining. The great challenge, in these cases, is to define what is the right moment for the transition of the methods, making sure that the results are optimized and one method do not impede the development of the other one. In this sense, it is necessary to analyze both options individually, mining the deposit only by open pit and mining only by underground, and also analyze the combination of the two methods, comparing these options technically and economically at the end, and then decide which project alternative is the best for each case.

Open pit mine operations are complex businesses that demand a constant assessment of risk. This is because the value of a mine project is typically influenced by many underlying economic and physical uncertainties, such as metal prices, metal grades, costs, schedules, quantities, and environmental issues, among others, which are not known with much certainty at the beginning of the project. Hence, mining projects present a considerable challenge to those involved in associated investment decisions, such as the owners of the mine and other stakeholders. In general terms, when an option exists to acquire a new or operating mining project, , the owners and stock holders of the mine project need to know the value of the mining project, which is the fundamental criterion for making final decisions about going ahead with the venture capital. However, obtaining the mine project’s value is not an easy task. The reason for this is that sophisticated valuation and mine optimisation techniques, which combine advanced theories in geostatistics, statistics, engineering, economics and finance, among others, need to be used by the mine analyst or mine planner in order to assess and quantify the existing uncertainty and, consequently, the risk involved in the project investment. Furthermore, current valuation and mine optimisation techniques do not complement each other. That is valuation techniques based on real options (RO) analysis assume an expected (constant) metal grade and ore tonnage during a specified period, while mine optimisation (MO) techniques assume expected (constant) metal prices and mining costs. These assumptions are not totally correct since both sources of uncertainty—that of the orebody (metal grade and reserves of mineral), and that about the future behaviour of metal prices and mining costs—are the ones that have great impact on the value of any mining project. Consequently, the key objective of this thesis is twofold. The first objective consists of analysing and understanding the main sources of uncertainty in an open pit mining project, such as the orebody (in situ metal grade), mining costs and metal price uncertainties, and their effect on the final project value. The second objective consists of breaking down the wall of isolation between economic valuation and mine optimisation techniques in order to generate a novel open pit mine evaluation framework called the ―Integrated Valuation / Optimisation Framework (IVOF)‖. One important characteristic of this new framework is that it incorporates the RO and MO valuation techniques into a single integrated process that quantifies and describes uncertainty and risk in a mine project evaluation process, giving a more realistic estimate of the project’s value. To achieve this, novel and advanced engineering and econometric methods are used to integrate financial and geological uncertainty into dynamic risk forecasting measures. The proposed mine valuation/optimisation technique is then applied to a real gold disseminated open pit mine deposit to estimate its value in the face of orebody, mining costs and metal price uncertainties.

La nécessité de maximiser la récupération d'une ou plusieurs espèces utiles d'un gisement du cuivre, l'optimisation des consommations d'additifs dans le processus de traitement métallurgique, savoir où laisser les matériaux qui dans le futur pourraient être valorisés par une série de nouvelles opérations etc., conduit à adapter la planification minière aux caractéristiques géologiques et métallurgiques du gisement.Les unités géo-métallurgiques sont déterminées par une combinaison des principaux paramètres géologiques, type de roche, altération, minéralisation, etc. Chaque unité présente un comportement différent au processus de traitement métallurgiques avec des caractéristiques de récupération et de consommation d'acide bien spécifiques.D'une façon générale, on peut définir la planification de la mine comme un outil permettant de faire la liaison entre la géologie et la métallurgie, non seulement selon des paramètres économiques et de teneurs, mais aussi selon des paramètres géologiques et métallurgiques.Pour pouvoir construire le modèle géo-métallurgique ou géo-minier métallurgique (G.M.M) ainsi que mettre en oeuvre la catégorisation des ressources, nous avons utilisé des outils géostatistiquesLe fait de disposer d'un modèle G.M.M est d'une grande aide pour la définition de la fosse finale et la planification à long terme, soit simplement comme une première approche de la réponse du gisement au processus de traitement métallurgique, mais surtout pour optimiser les coûts et définir différentes alternatives pour maximiser la récupération du métal.Cette étude a été appliquée au cas du gisement stratiforme de Cu et Ag de Mantos de la Luna situé dans le Nord du Chili. Il comporte en particulier une comparaison entre l'approche traditionnelle et l'approche qui intègre le concept du modèle G.M.M. qui porte principalement sur les teneurs de coupure. Le concept G.M.M. peut donc influencer les décisions stratégiques comme les décisions opérationnelles.

This study presents a comprehensive mathematical model for open pit mine block sequencing problem which considers technical aspects of real-life mine operations. As the open pit block sequencing problem is an NP-hard, state-of-the-art heuristics algorithms, including constructive heuristic, local search, simulated annealing, and tabu search are developed and coded using MATLAB programming language. Computational experiments show that the proposed algorithms are satisfactory to solve industrial-scale instances. Numerical investigation and sensitivity analysis based on real-world data are also conducted to provide insightful and quantitative recommendations for mine schedulers and planners.

Over recent years, new methods have been developed to integrate uncertainty into the optimization of life-of-mine (LOM) production planning. This thesis makes use of two stochastic optimization methods: simulated annealing (SA) and stochastic integer programming (SIP); which are implemented in the context of the requirements of mining applications through the use of stochastic simulation to model uncertainty. For the case of SA, the second chapter of the thesis documents the case of a copper deposit where ten simulated realizations are sufficient to provide stable LOM optimization results. In addition, the study shows that the selected true optimal pit limits are larger than the ones derived through conventional optimization. Stochastically optimized pit limits are found to be about 17% larger, in terms of total tonnage, than the conventional (deterministic) optimal pit limits. The difference adds one year of mining and approximately 10% of additional net present value (NPV) when compared to the NPV of conventional optimal pit limits and a production schedule generated stochastically with the same SA algorithm. In the third chapter of the thesis, the SIP based optimizer is used with the purpose of integrating uncertainty into the process of pushback design. Results show the sensitivity of the NPV to the design of starting and intermediate pushbacks, as well as the pushback design at the bottom of the pit. The new approach yielded an increment of ~30% in the NPV when compared to the conventional approach. The differences reported are due to the different scheduling patterns, the waste mining rate and an extension of the pit limits which yielded an extra ~5.5 thousand tonnes of metal.
Depuis quelques années, de nouvelles méthodes ont été développées pour intégrer l'incertitude dans l'optimisation de la planification de la production de la vie-de-mine i.e. life-of-mine (LOM). Cette thèse se sert de deux méthodes d'optimisation stochastique : recuit simulé (RS) et programmation en nombres entiers stochastique (SIP); les deux méthodes sont programmées dans le cadre des besoins des applications d'exploitation de la simulation stochastique et modélisation d'incertitude. Pour le cas de RS, le deuxième chapitre de la thèse décris le cas d'un dépôt de cuivre où dix réalisations simulées sont suffisantes pour fournir des résultats stables d'optimisation de LOM. En outre, l'étude prouve que les véritables limites optimales choisies de mine sont plus grandes que celles dérivées par l'optimisation conventionnelle. Des limites stochastiquement optimisées de mine s'avèrent environ 17% plus grandes, en termes de tonnage total, que les limites optimales (déterministes) conventionnelles de mine. La différence ajoute un an d'exploitation et approximativement 10% de valeur nette additionnel (NPV) une fois comparée au NPV des limites optimales conventionnelles de mine et une cédule de production produit stochastiquement avec le même algorithme de RS. Dans le troisième chapitre de la thèse, l'optimiseur basé sur SIP est utilisé en vue d'intégration de l'inceritude dans le processus de la conception de fosses emboîtées. Les résultats montrent la sensibilité du NPV à la conception de fosses emboîtées de commencement et intermédiaires aussi bien que la conception de la fosse emboîtée du fond de la mine. La nouvelle approche a produit une augmentation de ~30% dans le NPV une fois comparée à l'approche conventionnelle. Les différences rapportées sont dues aux différents cédules de production, du taux de décapage du stérile et d'une extension des limites de la mine qui ont produit ~5.5 mille tonnes supplémentaires

Thesis (MSc)--Stellenbosch University, 2011.
ENGLISH ABSTRACT: Ground-based mobile mine survey radars are much more common now than they were a few years ago. Their ever growing popularity instigated the need for streamlining their operating procedures. One such a procedure is that of georeferencing the radar within the mine coordinate frame. Mine surveying radars have traditionally been georeferenced using a triangulation technique called survey resectioning, a time consuming process where both models are placed within the common coordinate frame by tying the models together with known targets or beacons. Survey resectioning requires surveying knowledge as well as access to a theodolite, an expensive high precision optical instrument used for measuring horizontal and vertical angles to the known targets. It is also sometimes necessary for this procedure to be performed in extreme weather conditions. Due to the limitations mentioned, this alignment method is not always practical or accurate if not performed correctly by the operator. In this thesis we investigate a new georeferencing scheme for ground-based mobile mine surveying radar, using a software-implementable three-dimensional model alignment. The scheme considers alignment complexity of four degrees of freedom and requires only an estimated radar position for complete convergence. The new scheme is tested on data previously georeferenced using the existing method.
AFRIKAANSE OPSOMMING: Die gewildheid van grondgebaseerde mobiele myn-radars is vinnig wˆereldwyd aan die toeneem. Hulle word veral in oopgroef-myne aangetref. Hierdie snelgroeiende gewildheid het dit genoodsaak om hul roetiene-gebruiksprosedures te vereenvoudig. ’n Voorbeeld van ’n vereenvoudigde prosedure is om die radar makliker binne die myn-ko¨ordinaatstelsel te posisioneer. Dit is van uiterste belang dat hierdie prosedure so vinnig en akkuraat as moontlik moet geskied. Voorheen is hierdie radar-eenhede deur middel van ’n omslagtige driehoeksmetingstegniek geposisioneer (dikwels in ongunstige weersomstandighede). Hierdie tegniek (genoem landmetingskorrelasie), is ’n proses waar die radar-eenheid in die myn se ko¨ordinaatstelsel geposisioneer word deur middel van bekende punte of bakens. Landmetingskorrelasie vereis boonop van die gebruiker om landmetingskennis te hˆe asook om duur en ingewikkelde toerusting soos ’n teodoliet te gebruik. ’n Teodoliet word algemeen gebruik vir die opmeting van horisontale- en vertikale hoeke na bekende punte. Bogenoemde beperkinge van landmetingskorrelasie het tot gevolg dat die moontlikheid van verkeerde posisionering bestaan indien die oprerateur onervare is. Die proses kan ook lank neem. In hierdie studie word ’n nuwe radarposisioneringsproses ondersoek wat deur middel van drie-dimensionele modelbelyning geimplementeer word as ’n rekenaarprogram. Die proses neem vier grade van vryheid in ag, en benodig slegs ’n benaderde posisie van die radar-eenheid vir konvergensie. Die nuwe proses is getoets op bestaande data wat deur middel van die landmetingskorrelasie-metode belyn was.

Open pit mine production scheduling is a strategic decision-making problem that plays an important role in surface mining, as the economic viability of a mining project is highly dependent on careful long-term planning. An open pit mine production schedule seeks to determine the optimal sequence for a mineral deposit and the flow of materials within a mineral value chain (i.e., stockpiles, waste dumps and processing streams). This thesis investigates open pit mine production scheduling with the incorporation of Grade Engineering. The Grade Engineering concept was introduced by the Cooperative Research Centre for Optimising Resource Extraction. This thesis then, for the first time in the literature, develops and implements a new mixed-integer programming formulation for open pit mine production scheduling that considers Grade Engineering preconcentration techniques.

One of the most important properties of an explosive is its velocity of detonation (VOD). It is essential that the explosive should detonate at its optimum rate and release sufficient detonation pressure to get good fragmentation under the existing field conditions. The main objectives of this research study are to investigate the effects of explosive type, blast hole diameter, and degree of confinement on the VOD of bulk ANFO and bulk emulsion in Kumtor Open Pit Gold Mine. In this study, the continuous resistance wire method is employed to measure in-situ VOD of both bulk ANFO and bulk emulsion. The VOD values are measured for different hole diameters and under different confinements for both explosives. The ideality of bulk ANFO and bulk emulsion is calculated by comparing the in-situ measured VOD&rsquo
s and their ideal detonation values. It is found that the VOD of both explosives increases as the blast hole diameter and the degree of confinement increases. In addition to this, VOD of bulk ANFO decreases when it gets wet in the blast hole. Another finding is that, proportion of bulk emulsion ingredients has influence on its VOD. This research study provides a good understanding to use suitable explosive in existing rock conditions in Kumtor Open Pit Gold Mine.

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
Esta dissertação tem como objetivo principal estudar o comportamento dos taludes da mineração Pampa de Pongo, situada no Peru, em termos de deslocamentos e fatores de segurança contra ruptura por cisalhamento. As escavações atingem atualmente profundidades superiores a 900m com o corpo mineral seccionado por várias falhas geológicas que podem aumentar o potencial de risco de colapso dos taludes. As análises tensão x deformação foram executadas pelo método dos elementos finitos, em modelos bi e tridimensionais, considerando a existência e a ausência do sistema de falhas para melhor estimar e compreender a influência destas nos deslocamentos do maciço com o avanço das escavações. Este estudo também investigou as diferenças observadas nos resultados obtidos com dois programas comerciais de elementos finitos para solução de problemas geotécnicos (Phase2 e Plaxis 2D) tendo em vista as diferentes metodologias por eles empregadas na simulação de fraturas em meios contínuos. Nas análises de estabilidade os valores dos fatores de segurança determinados pelo método dos elementos finitos, em simulações 2D e 3D, foram também comparados com aqueles calculados por método de equilíbrio limite (método das fatias). De modo geral, observou-se que os efeitos das descontinuidades são maiores nos campos de deslocamentos horizontais e que também tendem a diminuir os valores de fator de segurança, inclusive para limites mínimos abaixo dos recomendados por normas brasileiras.
This thesis aims to study the behavior of the Pampa de Pongo open pit mine, situated in Peru, in terms of displacements and safety factors against shear failure. Excavations currently reach depths greater than 900m and the orebody is sectioned by several geological faults that may increase the potential risk of collapse of embankments. The stress x strain analyses were carried out by the finite element method, with two and three dimensional models, considering the existence and the absence of the fault system, to better estimate and understand the influence of these discontinuities in the displacements of the rock mass with the advancement of excavations. This study also investigated the differences in results obtained with two commercial finite element programs for solution of geotechnical problems (Phase2 and Plaxis 2D) since they use different techniques to simulate fractures in continuous media. In the stability analyses, the values of safety factors determined by the finite element method in 2D and 3D simulations were also compared with those calculated by the equilibrium method limit (method of slices). In general, it could be observed that the effects of discontinuities are larger on the horizontal displacement fields and they also tend to decrease the values of safety factors, even below the minimum thresholds recommended by Brazilian Standards.

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.

This thesis investigates factors that impact the energy efficiency of a mining operation. An innovative mathematical framework and solution approach are developed to model, solve and analyse an open-pit coal mine. A case study in South East Queensland is investigated to validate the approach and explore the opportunities for using it to aid long, medium and short term decision makers.

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village is within the close neighbourhood of the Western Lignite Corporation Y-3 panel. Although the nearest part of the mine is 1100 m and the farthest part is 2500 m from the village at present, some of the villagers complained about the ground vibration at the past. Therefore the assessment of damage risk and, if any, control and minimization of vibrations constitutes the aim and the scope of this research work. The researh work consists of monitoring of vibration, characterising of the seismic waves by full wave form analysis, and determination of magnitude and frequency of the waves from round blasting practice. Also dominant frequencies are determined, using single-hole blasting records by special software. The analyses are continued by a critical discussion and evaluation, and, proposals for new firing methods are made. The proposed firing methods are validated by further monitoring. As a result the best blasting practice was selected and offered to control and minimize the ground vibration.

An algorithm which adopts a moving cone approach but is guided by maximal network flow principles is developed. This study argues that from a network flow point of view, the re-allocation problem is a major obstacle to prevent a simulation oriented pit design algorithm from reaching the optimum solution. A simulation oriented pit design algorithm can not resolve the re-allocation problem entirely without explicit definition of predecessors and successors. In order to preserve the advantages of moving cone algorithm and to improve the moving cone algorithm, the new algorithm trys to avoid the re-allocation situations. Theoretical proof indicates that the new algorithm can consistently generate higher profit than the popular moving cone algorithm. A case study indicates that the new algorithm improved over the moving cone algorithm (1% more profit). Also, the difference between the new algorithm and the rigorous Lerchs-Grossmann algorithm in terms of generated profit is very insignificant (0.015% less). The new algorithm is only 2.08 times slower than the extremely fast moving cone algorithm. This study also presents a multi-period 0-1 programming mine sequencing model. Once pushbacks are generated and the materials between a series of cutoffs are available for each bench of every pushback, the model can quickly answer, period by period, what is the best (maximum or minimum) that can be expected on any one of these four items: mineral contents, ore tonnages, waste tonnages and stripping ratios. This answer is based on a selected cutoff and considers the production capacity defined by the ore tonnage, the desired stripping ratio and the precedence constraints among benches and pushbacks. The maximization of mineral contents is suggested to be the direct mine sequencing objective when it is permissible. Suggestions also are provided on how to reduce the number of decision variables and how to reduce the number of precedence constraints. A case study reveals that the model is fast and operational. The maximization of mineral contents increases the average grades in early planning periods.

The evaluation of risk is often performed assuming static conditions when in reality, conditions are continually evolving. In the following dissertation, the evaluation of risk with changing conditions over time is considered for a specific project - placing overburden into an active, open pit mine. The research focuses on the geotechnical components of risk with the goal of identifying whether and to what extent it is possible to place overburden on mined out portions of the open pit slopes. The relevant factors, which change with time or impact risk, are first identified and an evaluation is performed to estimate a probability of failure at various stages of the project life. Potential damages are then assessed by first evaluating the run out distance and post failure geometry of a slope failure and then estimating the percentage of material that would have to be removed to continue extraction of ore. To convert the uncertainty into economic terms, unit values for savings that result from placing overburden in the pit and costs associated with cleaning up failure debris are estimated. The probability of failure, potential for cleanup, and unit values are combined to produce estimates of the likely costs and benefits associated with dumping overburden in the open pit.The results of the analysis indicated that risk varies considerably with time. However, it is possible to place overburden in the central portion of the open pit up to a limit of approximately 80 million tons while maintaining a positive net value of expected costs and benefits.

Magíster en Minería. Ingeniero Civil de Minas
El diseño de taludes es una tarea crítica en proyectos de minería a cielo abierto. Generalmente, planificadores y diseñadores buscan operar en paredes tan empinadas como sea posible para optimizar la cantidad de mineral extraído y reducir el lastre. Sin embargo, esto conlleva una disminución en la estabilidad del talud. De este modo, se requiere una gestión adecuada del talud para permitir a los planificadores y operadores realizar su trabajo con seguridad. Una de las principales variables que debe ser manejada adecuadamente en minas a cielo abierto es la presión de poros que se genera detrás de los taludes ya que esta presión disminuye la resistencia al corte del suelo. Para controlar la influencia de la presión de poros se han desarrollado distintos tipos de instrumentos para monitorear presión de agua en minas y usar los datos obtenidos como input en la toma de decisiones. Entre los instrumentos desarrollados para monitorear presión de agua subterránea están los piezómetros, que se han convertido en tecnologías establecidas en proyectos civiles y mineros. Existen distintos tipos de piezómetros y entre ellos la tecnología más aceptada para realizar monitoreo de agua en minas es la de Vibrating Wire Piezometer (VWP). En esta tesis se desarrollaron lineamientos para seleccionar instrumentación basada en las características de una mina. Utilizando estos lineamientos se seleccionaros dos tecnologías para ser comparadas, los VWP y los Networked Smart Markers (NSM). Esta comparación involucra el desarrollo de un proyecto minero teórico que incluye empinar una pared potencialmente inestable de la mina como contexto para el uso de los instrumentos. Posteriormente, se desarrollaron lineamientos para integrar un programa de monitoreo al plan minero. Para comparar dichas tecnologías, se proponen dos programas de monitoreo equivalentes y se consideran los costos de los equipos para ser instalados en los años 3 y 13 del plan minero. Un análisis de pits anidados reveló que el VAN del proyecto aumenta a medida que la pared se empina, de este modo, el parámetro de control en la comparación es cuál programa es más barato al tomar en cuenta el ingreso extra y una tasa de descuento del 8% para calcular el VAN. Los resultados de esta comparación mostraron que el uso de VWP es más barato que el uso de NSM (600,015.5[US$] versus 766,142.5[US$]). Sin embargo, esta diferencia en costo es pequeña considerando la escala del proyecto (0.39% de la inversión), además empinar la pared generó 42,420,000[US$] extra al VAN original del proyecto, lo que hace que ambas alternativas sean factibles para llevar a cabo el monitoreo propuesto. Los NSM sin embargo poseen una ventaja para realizar mediciones multipunto ya que permiten un mayor número de puntos de muestreo en un mismo pozo.
Slope design is one of the most critical tasks in open pit mine projects. Generally, mine planners and slope designers aim to operate on walls as steep as possible to optimize the amount of ore retrieved from the mine while reducing the extracted waste. However, this approach also involves a reduction in overall slope stability. Consequently, a proper management of slope stability is required to assist mine planners and operators to perform their work safely. One of the main variables that need to be properly managed in open pit mines is the pore water pressure generated behind the slopes, as this pressure decreases the ground s shear strength. To manage the influence of pore water pressure, several geotechnical instruments have been developed over the years to monitor pore water pressure and to use the data to make proper decisions. Piezometers are devices developed to monitor groundwater pressure that have become established technologies to measure pore water pressure in civil and mining projects. There are different types of piezometers with varying characteristics. The most accepted sensing technology for pore pressure monitoring in mines is the Vibrating Wire Piezometers (VWP). This thesis developed guidelines for the selection of instrumentation given the characteristics of a mine site. Using those guidelines, Vibrating Wire Piezometers and the emergent technology of Networked Smart Markers (NSM) were selected to be compared. For this comparison, a theoretical mine project, that included the steepening of a potentially unstable wall, was developed as context for instrumentation use. Subsequently, guidelines for the integration of a pore water pressure monitoring program into the mine plan were developed. To compare the selected technologies, two equivalent monitoring programs were proposed considering the current installation costs of the devices and installations in years 3 and 13 of the mine life. A nested pit analysis revealed that the NPV of the project increases when the wall gets steeper, therefore, the parameter of interest is which program is less expensive compared to the extra income, considering a discount rate of 8% to calculate the NPV of the project. The results of this comparison showed that the use of Vibrating Wire Piezometers was less expensive than the NSMs (600,015.5[US$] against 766,142.5[US$]). However, this difference in cost is small in terms of the scale of this project (0.39% of the investment) and the steepening of the wall generated 42,420,000[US$] extra to the NPV of the original project, thus, making both alternatives feasible to perform the proposed monitoring. NSMs are, however, more suitable to perform multi-point readings as they allow a higher number of measurement points in a single borehole.

Rock mass classification schemes such as the Q System and Rock Mass Rating (RMR) System have been designed for prediction of tunnel support, but these systems can be modified from stability analyses to excavatability assessments. Five methods have been used to classify the rock mass at Globe-Progress with the objective of predicting the type of equipment that may be used to excavate the open pit: • Seismic velocity determination • Size-Strength Method • RMRSystem • Weaver's (1975) Rippability Rating System • MacGregor et al's (1994) Productivity Prediction Method Seismic velocity determination and the Size-Strength Method are both easily performed during the feasibility stages of a project. Seismic velocities are influenced by the degree of fracturing, compaction, porosity, density and weathering, and they can therefore be used to provide a preliminary characterisation of the rock mass. The Size-Strength Method uses the two most important properties of a rock mass for classification, the discontinuity spacing and the strength of the rock material. Both methods, therefore, provide quick and accurate assessments of the rock mass quality. At the investigation or design stage of a project a complete rock mass characterisation method is used that involves a collection of geological and geotechnical parameters to fully characterise the rock mass. The method chosen for use at Globe-Progress was the RMR system, as this method is easily adapted from a stability prediction method to an excavatability prediction method. Most data required for calculation of the RMR Index is available from drillcore data logs. Simple analyses of drillcore log data show that drillcore data has been correctly logged except for the strength parameter. This was revised for every logged rock mass unit (RMU) based on quantitative strength determinations and the lithology of each RMU, so that more accurate excavatability analyses could be made using the RMR System, a modified version of Weaver's 1975 Rippability Rating Method, and MacGregor et al’s 1994 Productivity Prediction Method. The ratings for the three rock mass classification methods employed have been contoured on plans at 20 metre bench levels. The plans show that zones of poor rock, where digging to easy ripping should be expected, exist in the western pit wall, where the Chemist Shop Fault is located, and along the northern and eastern walls, following the Globe-Progress Shear Zone. Most of the overburden is classed as fair to poor rock, where easy to moderate ripping will be expected, and there is a zone of weaker rock in the axial fold of the Globe-Progress Shear Zone. This study indicates that the proposed open pit is geotechnically feasible to rip. The preliminary assessments suggest that 90% of the pit area is rippable or marginal and 10% is expected to non-rippable. The final assessments suggest that ripping will be very easy (>3500m³/hr) to difficult (250 - 750 m³/hr) using a Komatsu D575A-2 Bulldozer. Some areas of overburden may require blasting to further fragment the rock mass and aid productivity. But there are other factors, such as the bulldozer operator's experience in ripping similar rock masses, wear and tear on ripper blades, bulldozer maintenance time and transportation costs, and other restrictions that influence overall productivity and costs associated with ripping, and which cannot be determined until ripping actually proceeds.

Traditional slope stability analysis and design methods, such as limit equilibrium method and continuum numerical methods have limitations in investigating three dimensional large scale rock slope stability problems in open pit mines associated with stress concentrations and deformations arising due to intersection of many complex major discontinuity structures and irregular topographies. Analytical methods are limited to investigating kinematics and limit equilibrium conditions based on rigid body analyses. Continuum numerical methods fail to simulate the detachment of rock blocks and large displacements and rotations. Therefore, there is an urgent need to try some new methods to have a deeper understanding of the open pit mine rock slope stability problems. The intact rock properties and discontinuity properties for both DRC and DP rock formations that exist in the selected open pit mine were determined from tests conducted on rock samples collected from the mine site. Special survey equipment (Professor Kulatilake owns) which has a total station, laser scanner and a camera was used to perform remote fracture mapping in the research area selected at the mine site. From remote fracture mapping data, the fracture orientation, spacing and density were calculated in a much refined way in this dissertation compared to what exist in the literature. Discontinuity orientation distributions obtained through remote fracture mapping agreed very well with the results of manual fracture mapping conducted by the mining company. This is an important achievement in this dissertation compared to what exist in the literature. GSI rock quality system and Hoek-Brown failure criteria were used to estimate the rock mass properties combining the fracture mapping results with laboratory test results of intact rock samples. Fault properties and the DRC-DP contact properties were estimated based on the laboratory discontinuity test results. A geological model was built in a 3DEC model including all the major faults, DRC-DP contact, and two stages of rock excavation. The built major discontinuity system of 44 faults in 3DEC with their real orientations, locations and three dimensional extensions were validated successfully using the fault geometry data provided by the mining company using seven cross sections. This was a major accomplishment in this dissertation because it was done for the first time in the world. Numerical modeling was conducted to study the effect of boundary conditions, fault system and lateral stress ratio on the stability of the considered rock slope. For the considered section of the rock slope, the displacements obtained through stress boundary conditions were seemed more realistic than that obtained through zero velocity boundary conditions (on all four lateral faces). The fault system was found to play an important role with respect to rock slope stability. Stable deformation distributions were obtained for k₀ in the range of 0.4 to 0.7. Because the studied rock mass is quite stable, it seems that an appropriate range for k₀ for this rock mass is between 0.4 and 0.7. Seven monitoring points were selected from the deformation monitoring conducted at the open pit mine site by the mining company using a robotic total station to compare with numerical predictions. The displacements occurred between July 2011 and July 2012 due to the nearby rock mass excavation that took place during the same period were compared between the field monitoring results and the predicted numerical modeling results; a good agreement was obtained. This is a huge success in this dissertation because such a comparison was done for the first time in the world. In overall, the successful simulation of the rock excavation during a certain time period indicated the possibility of using the procedure developed in this dissertation to investigate rock slope stability with respect to expected future rock excavations in mine planning.

In this thesis, it is aimed to investigate and analyze the effect of meteorological conditions on airborne dust measured at Ovacik Open Pit Gold Mine. Meteorological data must be sound and reliable which are used mainly to design an air model to predict the effect of industrial sites on air quality during production. Wind speed, wind direction, airtemperature, air pressure, relative humidity, rainfall, evaporation and sunshine. are the parameters investigated in this study. In the thesis, the meteorological data observed are analyzed and discussed together with the airborne dust measured by MP101M Suspended Particulate Beta Gauge Monitor at Ovacik Gold Mine. In this study, the most significant meteorological parameter affecting airborne dust concentration is determined as air temperature. In this study, it is also determined through airborne dust measurements that neither the short-term limit nor the long-term limit has been exceeded. Therefore, the airborne dust concentrations at Ovacik Gold Mine comply with the Turkish Air Quality Control Regulation.

This dissertation studies the evaluation of selectively mined, open pit gold deposits during the exploration stage of the mine's life. Since 1970 a large number of selectively mined, open pit gold mines have come into operation. The most common deposits include epithermal vein, mesothermal lode and laterite gold deposits. In general the deposits are characterized by small tonnages (1-20 million tonnes), relatively high grades (2-10 grams per tonne gold), submicroscopic to coarse gold, inexpensive mining, and both free milling and refractory ores.The key components that require evaluating during the exploration period are the deposit's geology, ore reserves, pit design, ore metallurgy and environmental impact. Feasibility studies are the main vehicle by which to report and guide the exploration programme. During the exploration period a company may undertake an initial (geological feasibility), second (preliminary mine feasibility) and third (final feasibility) delineation programme in order to gather sufficient data to justify a mine development decision. The responsibility of evaluating the mineral prospect lies primarily with the exploration geologist and mining engineer. Broad experience, a professional attitude, a thorough understanding of mining economics, and a high level of geological, engineering and technical skills are traits required by the evaluators. In order for mining companies to make sound investment decisions the geographical, geological, mining, metallurgical, environmental, marketing, political and financial aspects affecting the economic potential of the venture must be integrated so that the likely costs, risks and returns of the investment alternative are quantified. Ultimately, it is the economic analysis of these three items that determine whether the mineral prospect is developed into a mine I delineated further I retained until economic circumstances improve, or abandoned. To assess the costs, risks and returns, extensive use of the risk analysis is advocated throughout the exploration period . When combined with intelligent judgement of the intangible risk elements, the probabilistic distribution of discounted cash flows are invaluable in making sound investment decisions. However, the economic analysis is only as good as the information on which it is founded. Accurate and representative field data is the most important prerequisite to successfully evaluating and developing a new mine.

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.

Il lavoro di tesi studia le condizioni geologiche e strutturali della roccia, prima dell'estrazione mineraria, all'interno di uno specifico sito minerario, Meandu Mine, situato nel Queensland, in Australia. Tale analisi è stata condotta nell'ambito di un progetto di ricerca, finanziato dal programma di ricerca associato al carbone australiano (ACARP) e condotto dall'Università di Newcastle e CSIRO (Australia). In particolare, è stata eseguita l'analisi strutturale di tre strisce di parete appartenente al sito minerario (circa 1000 m di lunghezza × 300 m di larghezza × 100 m di profondità) mediante strumenti di modellazione geo-strutturale e tecnologie sviluppate da CSIRO (Australia).

Mining of lignite in Lusatia has a long history of over 100 years. The extracted brown coal is utilized to generate electricity in three large power plants: Jänschwalde, Boxberg, and Schwarze Pumpe. With an annual carbon dioxide (CO2) output of approximately 50 million tons, these power plants are among Germany’s large-scale CO2 emitters. The environmental impact from open-pit mining is of a considerable degree and currently poses a challenging problem. The groundwater deficit in 1990 was 7 billion m3 over a surface area of approximately 2100 km2 (Luckner, 2006a) and was bisected in value until today. Due to the decline of mining activity and the termination of mine drainage at most open pits in the Lusatian region, the groundwater table has recovered forming 28 pit lakes (Zschiedrich, 2011). The majority of the post mining lakes do not meet the quality standards for pH, iron or sulfate parameters; because of pyrite oxidation that produces acid mine drainage (Luckner, 2006b, Klapper and Schultze, 1995, Schultze et al., 2010). The post mining lakes in Lusatia have low pH values (3 – 4), high sulfate contents (up to 2800 ppm) as well as high iron concentrations (100 – 150 ppm). Lakes are flooded by groundwater and using surface water from Spree and Neisse River to achieve fast filling and dilution; however, due to the limited availability of surface water, further rehabilitation strategies for the region had to be investigated. Between 1970 and 1990, approximately 26 million m3 of suspended fly ash were deposited in the lake Burghammer and settled as an ash body at its base; where it may be used for rehabilitation. In a first experiment conducted in 2001 material from the ash body was picked up and redistributed throughout the lake. By this treatment the pH of the lake was raised temporarily; however, a sustainable remediation was not achieved. Based on these experiments it was investigated whether the ash reacts more sufficiently through additional CO2 injection or not. Aim was to combine the rehabilitation of acid mine lakes with the utilization of atmospheric carbon dioxide emissions from coal-fired power plants. The CO2 sequestration is achieved through the generation and accumulation of carbonates in the lake. The following equations describe the precipitation of carbonate by using CO2 and alkaline earth cations M: CO2 + MO → MCO3 (s) CO2 + M(OH)2 → MCO3 (s) + H2O Therefore, neutral pH conditions are necessary for the long-term accumulation of carbonates in the lakes. In laboratory investigations it was shown, that the 20 to 30 years old fly ash deposits of lake Burghammer can be used for carbonate sequestration and lake water treatment. Bivalent ions (Ca2+, Mg2+) are eluable and available for carbonate precipitation; on average we assumed 1 wt.-% of reactive calcium to be contained in the settled ash sediments. Settled fly ash sediments are less reactive than fresh fly ash from a power plant (e.g. Schwarze Pumpe). During batch experiments, we increased the buffering capacity to maximum values of 7 mmol/L. Beforehand no buffering capacity exists due to the low pH of 2.9 in the lake. Batch investigations provided a sequestration potential of 17 g CO2/kg ash sediment; in comparison fresh fly ash results in a sequestration potential of 33 g CO2/kg ash (Schipek and Merkel, 2008b, Schipek and Merkel, 2008a, Schipek, 2009). Based on the laboratory results a field experiment was conducted. In this field experiment gas injection lances were installed to a sediment depth of 12 m. Gaseous CO2 was applied with a pressure of 2.2 bar and 2.2 m³/h for 3 months and lake water was monitored during injection. Variations in total inorganic carbon due to diffusion processes of CO2 saturated pore waters could be observed. As the pilot experiment comprised only a small area of lake Burghammer no initial neutralisition (e.g. by a suction excavator) was possible. Thus, no further changes in water chemistry were observed. Drilling cores in the vicinity of the injection area provided mineralogical and geochemical conditions before and after CO2 treatment. No trace metal mobilization was found during CO2 injection. Most elements showed decreasing trends or didn’t change significantly. Calculated saturation indices for calcite indicated equilibrium conditions or slightly oversaturated conditions (SICalcite,average +0.12; SICalcite,median +0.31). Geochemical and mineralogical investigations proved that CO2 sequestration is possible with an average precipitation rate of 0.5 wt.-% (2.2 g CO2/kg). The maximum rate for carbonate precipitation was determined with 7.4 wt.-% Calcite, according to 32.6 g CO2 per kilogram treated ash. Besides the use of the settled fly ash as neutralizing agent in acidic mining lakes, laboratory and field investigations were conducted in order to improve in-lake liming. In batch and columns experiments, different liming agents (synthetic marble powder and industrial products) were tested and investigated. Significant differences in reactivity were obvious at pCO2 > 3.8 • 10-4 atm. Ions typical for acid mine drainage (e.g. Mn2+, Cd2+, SO42-) do have different effects on the kinetic of carbonate dissolution. Manganese concentrations typical for acidic mining lakes inhibit calcite dissolution. Cadmium has as well a significant influence on dissolution and kinetics. Only circa 50 % of the calcium concentration was reached with cadmium as inhibitor compared to the dissolution in pure water. Increased CO2 partial pressure might be used to compensate inhibtion by material impurities and/or water constituents. Column experiments showed that a multi-stage application of liming agent increases the efficiency of a lake treatment. The combination of a first application of calcite (up to pH 4.5) and further application of Ca(OH)2 seemed to be the most promising method. This treatment sheme was successfully applied in lake Burghammer from March 2009 – December 2010 (initial neutralisation and 6 follow-up treatments). Finally, it can be concluded, that in lignite mining districts in-lake treatment of acidic mining lakes is a seminal method to handle water quality problems. Using gaseous CO2 in combination with industrial by-products can be accounted as sustainable method for CO2 sequestration and for treatment of AMD. The advantage for mining areas lays in the prevention during treatment of acid mine lakes. Nevertheless, this method presents only a niche solution due to the dependence on alkaline materials, e.g. fly ash. The development of further strategies and optimization during lake water treatment by in-lake liming might improve the effectiveness of the method. Using calcite instead of NaOH or CaO as liming agent will provide advantages in being more economic and ecological (CO2 bilance). In order to enhance efficiency the use of calcite in combination with CO2 can be a worth considering suggesting. If meteorological parameters (wind) and lake specific characteristics (morphology, currents, etc.) will be considered efforts and costs for in-lake liming will be minimized
Der Abbau von Braunkohle im Lausitzer Bergbaurevier hat seit über 100 Jahren Tradition. Die abgebaute Braunkohle wird dabei hauptsächliche zur Energieerzeugung in den drei großen Kraftwerken Jänschwalde, Boxberg und Schwarze Pumpe genutzt. Mit einem jährlichen Kohlenstoffdioxid (CO2) – Ausstoß von circa 50 Millionen Tonnen gehören diese Kraftwerke zu Deutschlands größten CO2-Emittenten. Der Einfluss auf die Umwelt durch Tagebau-Betrieb ist von beträchtlichem Ausmaß und bringt große Probleme mit sich. Im Jahr 1990 betrug das Grundwasser-Defizit im Lausitzer Bergbaurevier 7 Milliarden m³ auf einer Fläche von circa 2100 km² (Luckner, 2006a). Dieses Defizit hat sich bis zum heutigen Zeitpunkt halbiert. Durch den Rückgang der Bergbauaktivitäten und die Beendigung der Wasserhaltungsmaßnahmen in den meisten Tagebauen, hat der ansteigende Grundwasserspiegel 28 Tagebaufolgeseen geschaffen (Zschiedrich, 2011). Der überwiegende Teil der Tagebaufolgeseen ist aufgrund der Pyritoxidation, welche AMD (acid mine drainage) produziert, hinsichtlich der Wasserqualitätsparameter stark beeinflusst (Luckner, 2006b, Klapper and Schultze, 1995, Schultze et al., 2010). Die Tagebaufolgeseen im Lausitzer Bergbaurevier sind durch niedrige pH-Werte (3 – 4), hoche Sulfat-Konzentrationen (bis zu 2800 ppm) und hohe Eisengehalte (100 – 150 ppm) gekennzeichnet. Die entstehenden Seen sind hauptsächlich durch aufsteigendes Grundwasser und Oberflächenwasser aus den Flüssen Spree und Neisse geflutet. Aufgrund der geringen Verfügbarkeit von Oberflächenwasser mussten weitere Sanierungsmaßnahmen für die Region untersucht werden. Zwischen 1970 und 1990 wurden im Tagebaufolgesee Burghammer circa 26 Millionen m³ Flugasche-Suspension als Aschekörper abgelagert, wobei eine Nutzung zu Sanierungszwecken angedacht war. Im Rahmen einer Aschesedimentumlagerung im Jahr 2001 wurde der pH-Wert des Seewassers kurzzeitig angehoben, eine nachhaltige Sanierung fand jedoch nicht statt. Auf Grundlage dieser Ergebnisse wurde im Rahmen dieser Dissertation untersucht, ob die abgelagerten Aschesedimente nachhaltiger durch Einsatz von CO2 reagieren. Ziel war es die Sanierung von Tagebaufolgeseen mit der Reduktion von CO2-Emissionen aus Kohlekraftwerken zu kombinieren. Diese CO2-Sequestrierung sollte durch die Bildung und Ablagerung von Carbonaten im Seesediment erfolgen. Die Gleichungen (1) und (2) beschreiben dabei die Fällungsreaktion von Carbonaten aus CO2 mit dem Alkalimetall M (aus Oxiden bzw. Hydroxiden): CO2 + MO → MCO3 (s) CO2 + M(OH)2 → MCO3 (s) + H2O Zur Carbonatfällung und nachhaltigen Ablagerung sind neutrale pH-Bedingungen notwendig. In Laboruntersuchungen konnte gezeigt werden, dass die 20 bis 30 Jahre alten Flugaschesedimente zur CO2-Sequestrierung in Kombination mit Seewasserbehandlung genutzt werden können. Zweiwertige Ionen (Ca2+, Mg2+) sind aus den Aschesedimenten eluierbar und stehen für die Fällungsreaktion zur Verfügung. Durchschnittlich 1 Masse-% reaktives Calcium befindet sich in den Sedimenten. Die abgelagerten Aschesedimente sind dabei weniger reaktiv als frische Flugaschen aus Kohlekraftwerken (z.B. Schwarze Pumpe). In Batch-Versuchen mit Tagebaufolgesee-Wasser konnte die Säure-Pufferkapazität auf maximal 7 mmol/L erhöht werden. Sequestrierungs-Raten von 17 g CO2/kg Aschesediment wurden im Rahmen der Versuche erreicht. Im Vergleich dazu betrugen die Sequestrierungs-Raten in Versuchen mit frischen Flugaschen bis 33 g CO2/kg Asche (Schipek and Merkel, 2008b, Schipek and Merkel, 2008a, Schipek, 2009). Auf Grundlage dieser Laborergebnisse wurde ein Feldversuch im Tagebaufolgesee Burghammer geplant. Während diesem wurden Gasinjektionslanzen bis in eine Sedimenttiefe von 12 m im abgelagerten Aschesediment installiert. Gasförmiges CO2 wurde mit einem durchschnittlichen Druck von 2.2 bar und 2.2 m³/h für eine Dauer von 3 Monaten injiziert. Während dieser Zeit fand ein kontinuierliches Monitoring des Seewassers im Bereich der Injektion statt. Veränderungen des Gehaltes an TIC (total inorganic carbon) aufgrund von Diffusionprozessen von CO2-gesättigtem Porenwasser aus dem Aschekörper waren beobachtbar. Da der Feldversuch nur in einem begrenzten Bereich des Tagebaufolgesees Burghammer stattfand und keine Initialneutralisierung vorsah, konnten keine weiteren, großmaßstäblichen Veränderungen im Wasserkörper festgestellt werden. Bohrkernentnahmen im Umfeld des Behandlungsgebietes lieferten Aussagen bezüglich der mineralogischen und geochemischen Beschaffenheit vor und nach CO2-Injektion. Im Porenwasser wurde keine Spurenmetall-(re)-mobilisierung durch die Behandlung mit CO2 festgestellt. Nahezu alle Elemente zeigten einen abnehmenden Trend durch die Behandlung mit CO2, bzw. keine signifikanten Veränderungen. Modellierte Sättigungsindizes für Calcit wiesen auf Gleichgewichtsbedingungen oder leichte Übersättigung bzgl. Calcit hin (SICalcit, Mittelwert +0.12; SICalcit, Median +0.31). Geochemische und mineralogische Untersuchungen zeigten, daß CO2-Sequestrierung mit einer durchschnittlichen Fällungsrate von 0.5 Masse-% (2.2 g CO2/kg Aschesediment) erreicht wurde. Die maximale Fällungsrate wurde mit 7.4 Masse-% Calcit bestimmt, dies entspricht einer Festlegung von 32.6 g CO2/ kg Aschesediment. Neben der Nutzung der abgelagerten Aschesedimente zur Behandlung des Tagebaufolgeseewassers wurden desweiteren Labor- und Feldversuche durchgeführt um In-Lake-Behandlungen mit industriellen Kalkprodukten zu optimieren. In Batch- und Säulenversuchen wurden verschiedene Kalkprodukte (synthetisches Marmorpulver und industrielle Produkte) getestet und untersucht. Signifikante Unterschiede auf die Reaktivität wurde bei erhöhten CO2-Partialdrücken (pCO2 > 3.8 • 10-4 bar) beobachtet. Wasserinhaltsstoffe, die typisch für AMD sind (z.B.. Mn2+, Cd2+, SO42-) zeigten einen signifikanten Einfluss auf die Calcit-Lösungskinetik. Mangankonzentrationen, wie sie in Lausitzer Tagebaufolgeseen vorkommen, zeigten – ebenso wie Cadmium - eine inhibitierende Wirkung auf die Kinetik. Im Vergleich zu Versuchen mit destilliertem Wasser wurden nur ungefähr 50 % der Calcium-Gleichgewichtskonzentration mit Cadmium als Inhibitor erreicht. Erhöhte CO2-Partialdrücke könnten genutzt werden, um die inhibitierende Wirkung von vorhanden Materialverunreinigungen und/oder Wasserinhaltsstoffen zu kompensieren. Säulenversuche zeigten, dass der mehrstufige Einsatz von Kalkprodukten die Effizienz während einer Seewasserbehandlung erhöht. Die Kombination einer Erstbehandlung mit Kalksteinmehl (bis pH 4.5), und einer Behandlungsfortsetzung mit Ca(OH)2 erwies sich als wirkungsvollste Methode. Dieses Behandlungsschema (Initialneutralisation, 6 Nachfolgebehandlungen) wurde im Tagebaufolgesee Burghammer von März 2009 – Dezember 2010 erfolgreich angewandt. Zusammenfassend lässt sich sagen, dass in ehemaligen Bergbaurevieren die In-Lake-Behandlung von Tagebaufolgeseen eine zukunftsträchtige Methode zur Behandlung von Wasserqualitätsproblemen darstellt. Die Nutzung von gasförmigen CO2 in Kombination mit industriellen „Abfall-Produkten“ kann als nachhaltige Methode zur CO2-Sequestrierung und zur Behandlung von AMD bezeichnet werden. Der Vorteil in Bergbaurevieren liegt dabei in der Vorbeugung der Entstehung von Wasserqualitätsproblemen. Dennoch stellt diese Methode nur eine Nischenlösung aufgrund der Verfügbarkeit der alkalischen Materialien (Flugasche) dar. Die Entwicklung und Optimierung weiterführender Strategien zur In-Lake-Behandlung durch Kalkung wird zur Effizienzerhöhung beitragen. Die Nutzung von Kalksteinmehl anstelle von NaOH bzw. CaO als Neutralisationsprodukt wird Vorteile hinsichtlich ökonomischer und ökologischer Sicht (CO2-Bilanz) mit sich führen. Um die Effizienz beim Einsatz von Kalksteinmehl zu steigern, kann der Einsatz von CO2 in Betracht gezogen werden. Sobald meteorologische Parameter (Wind) und see-spezifische Merkmale (Morphologie, Strömungen, etc.) berücksichtigt werden, kann der Aufwand und die Kosten für In-Lake-Behandlungen minimiert werden

Slope surface deformation monitoring in open pit mines is an essential component of day-to-day operations, playing a key role in assisting mine operators in maintaining safety and production schedules. The introduction of ground-based radar within the past decade to complement conventional geodetic monitoring programs provides near real-time deformation measurements over a broad coverage area; this allows geotechnical engineers to observe the distribution of pit wall movements and their progression over time. However, when a slope deformation alarm and/or accelerating deformation trend is observed in the radar measurements, common practice is to arbitrarily select a single or small cluster of pixels for analysis rather than following a systematic procedure that utilizes the full coverage. In addition, the absence of a methodical means of efficiently carrying out “Time-of-Failure” (TOF) analyses in real time can limit the effectiveness of the early warning, pressuring the geotechnical engineer to provide action response recommendations based on a partial and/or subjective assessment. This thesis presents a new systematic multi-pixel selection technique termed the “percent deformation method” where a benchmark pixel is methodically chosen within the deforming slope and multiple surrounding pixels are selected based on a percentage of the benchmark deformation. The percent deformation method was applied to eight slope failures captured by GroundProbe Slope Stability Radar (SSR) and detailed back-analyses conducted for each case using both the inverse-velocity and the SLO TOF analysis methods. The percent deformation multi-pixel selection technique was then incorporated into a newly proposed real-time TOF analysis procedure designed for use with ground-based radar measurements. The utilization of the percent deformation method in the proposed real-time TOF analysis methodology gives more reliable results than current practice by providing recommendations for pixel selections, data filtering, where and how to undertake TOF analyses, and presenting TOF results in real time. It is hoped that the addition of a more rigorous, methodical treatment of radar monitoring data when faced with a critical slope instability will reduce uncertainty and increase confidence in any trigger action response decisions, helping to ensure a safer work environment.

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

Este trabalho propõe uma metodologia inovadora de seqüenciamento de lavra em minério de ferro a qual, além de considerar os parâmetros operacionais e econômicos das técnicas tradicionais, permite uma abordagem ambiental proativa para sequenciar a lavra de forma a antecipar a exaustão de parte da cava para disposição do estéril dentro da cava final. A metodologia proposta de seqüenciamento ordenado de lavra permite reduzir a área degradada a ser reabilitada na mina, com significativos benefícios associados à reducão do impacto ambiental, sem comprometer as metas de produtividade e competitividade econômica da lavra. A metodologia de seqüenciamento ordenado de lavra foi aplicada em um estudo de caso de projeto de lavra de minério de ferro, e os resultados alcançados comprovaram os benefícios esperados com a aplicação da metodologia proposta.
This paper presents a innovative approach for an environmentally pro-active mine scheduling process. The proposed methodology has been developed for identifying a mine sequence that meets all operational and economical constraints in iron-ore mining, and takes into account a pro-active approach for scheduling the mine according to environmental criteria. The proposed methodology allows a significant reduction of the environmental impact related to the mining operation without compromising productivity and the economical feasibility of the mine. The methodology has been applied to a case study of iron ore mining in Brazil, where the expected benefits have been proven.

A operação e gerência de empreendimentos mineiros são tarefas normalmente difíceis e complexas. Para otimizar toda a operação, os engenheiros precisam lidar com muitos aspectos técnicos e restrições, como a modelagem geológica, estimativa de reservas, determinação da necessidade de blendagem, projeto das cavas ótimas e operacionais, custos operacionais, questões ambientais, entre outros. Nesse sentido, o posicionamento de infraestruturas de superfície é um dos pontos críticos dentro do planejamento de mina. Aproximar as estruturas da cava, com o intuito de reduzir custos operacionais, pode interferir em eventuais expansões da cava em novos e favoráveis cenários. Nesses casos, impactos no valor presente líquido (VPL) do projeto são inevitáveis e precisam ser tratados tecnicamente, avaliando um grande número de cenários alternativos para delinear uma estratégia que incremente a lucratividade do projeto. O objetivo deste estudo é avaliar, por meio de comparações de VPL entre diferentes cenários de múltiplas restrições de superfície, sob incerteza geológica, a possibilidade de mover pilhas de estéril e outras infraestruturas de suas atuais posições e/ou definir prioridades e mensurar o impacto que cada restrição representa na lucratividade do projeto. A metodologia foi aplicada a uma mina de fosfato para ilustrar como determinar a melhor alternativa em uma perspectiva de planejamento de mina de longo prazo. Utilizando o método de cavas híbridas, aplicado ao modelo de teores simulados, foi possível identificar zonas de probabilidade de ocorrência dentro da cava matemática, o que forneceu informações cruciais para auxiliar na tomada de decisão a respeito da necessidade de relocação de estruturas.
The operation and management of mining enterprises are usually difficult and complex tasks. To optimize the entire operation the engineers must deal with several technical aspects and constraints, such as orebody modelling, reserves estimation, determination of blending necessity, optimum and operational pit designs, operational costs, environmental issues, among others. In this sense, locating surface infrastructures is one of the most critical mine planning concerns. Approximating these structures to the pit, in order to reduce the operational costs, might interfere with future pit expansions in new favorable scenarios. In such cases, impacts on project’s net present value (NPV) are inevitable and must be deal technically, evaluating several alternative scenarios to delineate a strategy to maximize profitability. The aim of this study is to evaluate, through NPV comparisons considering different scenarios with multiple constraints, under geological uncertainty, the possibility of moving waste piles and infrastructure buildings from their current position and/or defining priorities to after measuring the impact that each constraint represents on the project´s profitability. The methodology will be applied to a phosphate mine, to determine the best alternative from a long-term mine planning perspective. Using the hybrid pits method, applied to a simulated grades model, allowed the identification os occurrence probability zones within mathematical pit, providing critical data to support decision making regarding infrastructure relocation.

Métodos de estudo de estabilidade de taludes são diversificados e estão bastante desenvolvidos e consolidados na Geologia de Engenharia. Paralelamente, a aplicação de ferramentas de geoprocessamento tem se intensificado bastante em todos os campos de conhecimento técnico científico, demonstrando ser uma ferramenta de grande importância e auxiliando a tomada de decisão, sendo inclusive utilizado no estudo de escorregamentos e processos correlatos a instabilização de taludes. Dentro deste contexto, este trabalho objetivou desenvolver uma abordagem de estudo para caracterizar a estabilidade de taludes de mineração combinando técnicas e métodos usuais de investigação e análise geológico-geotécnica. A pesquisa foi aplicada nas minas de ferro do complexo Fazendão, localizadas no município de Catas Altas (MG) e são de propriedade da companhia VALE S/A. O trabalho está dividido essencialmente em duas etapas de estudo: primeiramente um foco semi-regional, seguido de um estudo de detalhe em uma mina em particular. Para a análise semi-regional foi utilizando Sistema de Informação Geográfica - SIG para geração de mapas temáticos, abrangendo todas as minas do complexo. Já no estudo de detalhe, foram realizados levantamentos sistemáticos em campo na mina de São Luís, sendo posteriormente realizado um levantamento específico de seções dentro da mina. A partir dos mapas temáticos foram identificadas as principais drenagens e bacias hidrográficas da área de estudo. Estes mapas juntamente com os mapas de declividade, curvatura, direção de vertente e mapa geológico, forneceram informações importantes sobre a região onde as minas estão inseridas, o que possibilita um melhor planejamento das intervenções que vierem a serem feitas. As análises por estereogramas indicaram várias situações de instabilidade frente às direções de fraturas e bandamento, com relação à direção e ângulo de mergulho de alguns taludes, sendo várias destas feições identificadas em campo. Por outro lado, a análise por equilíbrio limite apontam fatores de segurança muito altos, desde que não ocorra a influência do nível de água. Por fim, a abordagem utilizada foi bastante útil na caracterização da região. O estudo semi-regional em conjunto com uma análise de detalhe permitiu identificar feições que comprometem a segurança dentro da mina. A partir do resultado deste estudo, espera-se auxiliar a programação do avanço da mina de forma otimizar sua exploração, sem comprometer a segurança.
Methods of study of slope stability are diverse and are well developed and consolidated in Engineering Geology. In addition, the application of GIS tools has intensified greatly in all fields of scientific expertise, proven to be an important tool aiding in the decision making, including being used in the study of landslides and processes related to slope instability. Within this context, this study aimed to develop a approach to characterize the stability of slopes mining combining geoprocessing techniques and the usual methods of investigation and analysis of geological-geotechnical. The research was applied to the iron mines of Fazendão complex, located in the municipality of Catas Altas (MG) and are the property of the company VALE S/A. The research is divided into two main stages of the study: first a semi-regional focus followed by a study in detail of a particular mine. For the semi-regional analysis has been using GIS for thematic maps, covering all the mines the complex. In the study of detail, systematic surveys were conducted in the field for geological and geotechnical parameters in the mine of São Luís, and later conducted a survey within specific sections of the mine. From the thematic maps were identified the major drainage and hydrographic basins of the study area. Those maps, analyzed together with the slope map, curvature, direction of slope and geologic map provided important information about the area which the mines are located, allowing better planning of interventions that were to be made. The stereograms analyzes indicated various situations of instability depending of the fractures and banding directions, according to direction and dip angle of some slopes, some of it identified in the field. Moreover, the limit equilibrium analysis safety factors showed very high, since there was no influence of the water levels. Finally, the used approach was useful in characterizing the region. The semi-regional study combined with a detail analysis allowed to identify features that compromise the safety inside the mine. From the results of this study is expected to help advance the schedule of the mine in order to optimize their operations, without compromising security.

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.

Pour contribuer à la compréhension des processus d'arrachement et de fragmentation de la roche par l'explosif en ciel ouvert, le travail de recherche présenté dans ce mémoire vise à affiner les techniques empiriques de prédiction de fragmentation existantes. Un programme expérimental conséquent réalisé en échelle réelle sur site minier apporte des données ainsi que de nouveaux éléments par rapport à l'existant dans la littérature. En particulier, une comparaison entre résultats de tirs de charge unique et résultats de tirs à plusieurs charges est faite. Dans le contexte roche/explosif du site test, les résultats démontrent que le bénéfice industriel d'une prédiction charge par charge est limité. Une approche numérique a été mise en œuvre en parallèle du travail expérimental ; elle met à contribution un modèle rhéologique d'endommagement développé spécifiquement pour l'étude de laf ragmentation par l'explosif (Rouabhi, 2004). Des calculs 2D avec réduction d'échelle ont été réalisés ; l'utilisation d'un tel modèle d'endommagement s'avère indispensable, et la nécessité de coupler dans le futur les effets des ondes de choc et des gaz d'explosion dans la modélisation est soulignée. On explique par ailleurs de manière originale les résultats d'une étude expérimentale en laboratoire (Miklautsch et al., 2002). En fin de mémoire, plusieurs méthodologies de prédiction charge par charge aisément reproductibles sont testées et ajustées aux résultats du programme expérimental. On finit par montrer que la meilleure méthode offre même davantage de précision lorsqu'elle est appliquée avec les paramètres moyens des tirs et non charge par charge.

La demande mondiale en ressource minérale en général et celle du phosphate en particulier connait une forte croissance depuis plusieurs années. C’est dans ce contexte tendu que chaque industriel cherche à être pionnier et à réduire ses coûts afin d’assurer sa pérennité tout en étant soumis aux contraintes légales dans une perspective de développement responsable. Face à des enjeux comparables, plusieurs industries manufacturières se sont orientées avec succès depuis plusieurs décennies vers l’approche japonaise du Lean Management. C’est pour cette raison que nous avons réfléchi à proposer à travers ce projet de recherche une méthodologie pour le Lean Mining Responsable visant à améliorer l’efficacité et l’efficience de l’industrie minière. L’ensemble des méthodes, briques logicielles et concepts proposés dans cette thèse ont été construit à partir d’un retour d’expérience réalisé sur le système minier d’extraction du phosphate de l’axe centre de l’OCP SA. Nos travaux, réalisés sous la forme d’une recherche action, se caractérisent par des apports à 3 niveaux :Apports méthodologiques ; nous proposons la Méthodologie ASCI-LM pour évaluer l’impact sur l’organisation industrielle liés à la mise en place d’outils et de méthodes en contexte minier. Cette approche constitue un guide méthodologique permettant une recherche action dans le contexte de l’industrie minière. Ce guide méthodologique explique comment formaliser les modèles de connaissance (cartographie des flux) et comment imbriquer les modèles informatiques permettant d’évaluer informatiquement des scenarios organisationnels liés à des problèmes de coordination des activités en contexte minier.Briques logicielles pour l’aide à la décision ; l’interdépendance spatio-temporelle qui caractérise la chaîne minière, rend difficile la prédiction de l’impact de la décision prise. Ce point est un facteur-clé qui explique la démotivation de l’industrie minière à l’égard de la mise en œuvre du Lean Mining. Un système d’aide à la prise de décision pour l’industrie minière aura comme objectif de pouvoir reproduire la réalité et par la suite de tester l’impact de différentes décisions en prenant compte de : l’état du gisement, le programme de maintenance, la disponibilité des machines, les demandes à satisfaire… Les décisions prises dans le processus extractif auront comme impact sur : l’évolution des stocks de minerai, l’occupation des machines mobilisées, la satisfaction de la demande… Nous proposons deux briques logicielles dont la première porte sur la planification minière pour assurer un pilotage intégré de la mine et aider à la prise de décision dans un délai court. La deuxième brique logicielle que nous avons imaginée évalue / optimise les méthodes d’organisations industrielles de la mine lors de la constitution des « mélanges » de minerai ; le mélange de minerai constitue l’output commercialisable du système minier et qui est envoyé aux clients internes ou externes de la supply chain minière. Nouvelles méthodes d’organisation industrielle ; Nous avons proposé une méthode de constitution des mélanges de minerai qui change complètement celle utilisée actuellement. Cette dernière est basée sur une logique de nomenclature figée alors que nous proposons des nomenclatures dynamiques que nous avons appelés « blending dynamique ». Ces nomenclatures dynamiques visent à définir les mélanges optimaux qui varient au fil du temps en fonction des minerais extrait du chantier et de leur composition chimique. Malgré les réticences qui pouvaient y avoir pour adopter cette approche (ce qui est logique dans une organisation « historique »), les mineurs ont montré un grand intérêt vis-à-vis de l’approche qui a été validée sur le terrain et qui est même généralisable sur d’autres contextes
Global demand for mineral resources in general, and phosphate in particular, has been growing strongly for several years. In this increased competitive environment, every industry seeks to be pioneering and to reduce its costs to ensure its sustainability while complying with new responsible development regulations. Faced with this kind of challenges, a number of manufacturing industries have turned to the Japanese Lean Management approach. With this in mind, we designed our research project to develop a Lean Sustainable Mining methodology aimed at improving the mining industry’s efficiency and effectiveness at the OCP-SA center axis phosphate mine. We first conducted a detailed review of the Lean Mining (LM) literature to assess how well such an approach had already been implemented, which points are directly relevant to the mine and which are not. We also reviewed the implementation methodologies and assessed how effectively they were used. This analysis highlighted multiple shortcomings including in relation to the methodological approaches, the software bricks for decision support systems, the industrial organization methods and adequate factoring in of all energy-related aspects.We first recommend applying the ASCI (Analyze, Specification, Conception, Implementation) methodology to LM in order first to identify all the steps upstream of development of the relevant knowledge model and then the associated action model. This phase was developed based on a thorough analysis of mine soil characteristics in order to build a robust knowledge base. This methodology was then applied to the Ben Guerir mine. We believe that this methodological approach will be found useful by other industries in their effort to switch to LM.Our next step was to construct a model based on discrete event simulation for short-term decision support of mine extraction planning. This model closely matches current extractive process operations (drilling, blasting, etc.) and takes into account all the constraints whether they be in relation to the field (geology, blocks, state of the initial system, distances, ...) or to the equipment (capacity differences, technical downtime, ...). Other considerations that we factored in include the decisions taken upstream of the chain (priority source layers, maintenance program, orders, among others). The model yields the following output: deposits blocks to be extracted in order to meet the demand defined over the planning horizon, the equipment Gantt to define the route to be taken by each piece of equipment and the cumulative feed curves for extracted source layers. The purpose is to extract material required by the downstream blending process, while avoiding any non-value added activities, and to improve overall chain performance.The phosphate industry needs to define the blends used to produce the ore qualities to be shipped to domestic and international customers. We have proposed a new method for optimal definition of these blends designed to replace fixed bills of materials by dynamic ones that change over time. Our "dynamic blending" model serves to define, based on available source layer stocks i) the feedings to be conveyed from the deposit to the stock and ii) the optimal quantities to be extracted from each layer while meeting the customer’s quality specifications charter. The purpose of this approach is to produce the right quality, preserve the phosphate-rich layers for the future, streamline stocks and ensure a connection between the pushed upstream flow (deposit) and the pulled downstream flow (definition of blends)
إن الطلب العالمي على الموارد المعدنية بشكل عام، والفوسفاط على وجه الخصوص، يزداد بسرعة منذ عدة سنوات. وفي هذا السياق الذي يعنى بمنافسة قوية بين الأطر الفعالة، يسعى كل مصنع الى أن يكون الرائد في مجاله، وأن يقلل من تكاليف الإنتاج من أجل ضمان متانته في إطار خضوعه لقيود قانونية تحت منظور التنمية المسؤولة. في إطار مواجهة قضايا مماثلة، انتقلت العديد من الصناعات التحويلية، بنجاح لعدة عقود، إلى تطبيق النهج الياباني Lean Management. ولهذا السبب، فكرنا من خلال مشروع البحث هذا في اقتراح منهجية من أجل Lean Mining مسؤول، هدفه تحسين كفاءة وفعالية صناعة المعادن. جميع الطرق والمنهجيات ومفاهيم البرمجيات المقترحة في هذه الأطروحة يتم بناؤها على أساس تجارب منجزة على نظام الصناعة المعدنية لاستخراج الفوسفاط للمحور المركزي لـ OCP-SA. يتميز عملنا، الذي تم تنفيذه على شكل بحث-عملي، بمساهمات على 3 مستويات:مساهمات منهجية: نقترح منهجية ASCI-LM لتقييم تأثير تنفيذ أساليب على المنظمة الصناعية المتعلقة بالصناعة المعدنية. هذا النهج هو عبارة عن دليل منهجي للبحث-العملي في هذا المجال، الذي يشرح كيفية إضفاء الطابع الرسمي على نماذج المعرفة (رسم خرائط التدفقات) وكيفية تضمين النماذج المعلوماتية التي تجعل من الممكن تقييم سيناريوهات تنظيمية تتعلق بمشاكل التنسيق بين الأنشطة في سياق الصناعة المعدنية.أسس البرمجيات لدعم اتخاذ القرار: إن الترابط الزمكاني الذي يميز سلسلة التعدين اللوجستيكية يجعل من الصعب التنبؤ بأثر القرار المتخذ. هذا الترابط يعتبر العامل الرئيسي الذي يفسر إبطاء صناعة التعدين فيما يتعلق بتطبيق ونهج سياسة Lean Mining. يهدف نظام دعم القرار الخاص بصناعة التعدين إلى إعادة إنتاج الواقع ومن ثم اختبار أثر القرارات المتخذة، مع الأخذ بعين الاعتبار: هيئة المنجم، برنامج الصيانة، توفر الآلات، المطالب الواجب تلبيتها ... القرارات التي اتخذت في سلسلة عملية الاستخراج سيكون لها تأثير على: تطور مخزونات المادة الخام، مدى استعمال الآلات المخصصة لذلك، و تلبية المطالب ... نقترح اسسين اثنين من البرمجيات: يتناول الأول تخطيط التعدين لضمان الإدارة المتكاملة للمنجم والمساعدة في اتخاذ القرار في وقت قصير. أما الثاني فيهتم بتقييم / تحسين أساليب التنظيم في المنجم أثناء تكوين "خليط" انطلاقا من المواد الخام؛ ويعتبر هذا الأخير الناتج النهائي القابل للتسويق في إطار النظام اللوجستيكي للتعدين، ويتم إرساله إلى الزبناء الداخليين أو الخارجيين لسلسلة التوريد.أساليب جديدة للتنظيم الصناعي: لقد اقترحنا طريقة لتكوين خليط من المواد الخام والتي تختلف تماما عن الطريقة المستخدمة حاليًا. وتستند هذه الأخيرة على منطق التركيبة الثابتة في حين أننا نقترح تركيبات ديناميكية أطلقنا عليها إسم "المزج الديناميكي". تهدف هذه التسميات الديناميكية إلى تحديد الخلطات المثالية التي تتغير بتغير الوقت، اعتمادًا على المواد الخام المستخرجة وتركيبتها الكيميائية. وبالرغم من الإحجام عن تبني هذا النهج (وهو أمر طبيعي في إطار تنظيم ذو أسس "تاريخية عريقة")، فقد أظهر عمال المناجم اهتماما كبيرا بالنهج المقترح والذي تم التحقق من مصداقيته في هذا المجال والذي من الممكن تعميمه في مجال صناعي آخر

M.Ing. (Engineering Management)
The design of the optimum open pit slope angle is one of the major challenges during open pit mine planning, as it implies attaining the ideal balance between utilizing the maximum slope angle whilst achieving acceptable stability and safety standards as indicated by the mine. The aim of open pit mines should thus be to seek the steepest possible slope angle without compromising the safety of the personnel, equipment or ore reserves, utilizing both stability analyses as well as risk assessments. The typical open pit mine plan aims to achieve an acceptable balance between operational risks and geotechnical design considerations by analysing factors such as the slope stability design, the rock mass properties and existing structural geological conditions. These factors are used as inputs towards an optimum slope angle design which will be used in the final pit design and aims to provide maximum economic viability to the mine. The risk analysis methodology aims to improve traditional slope design methods and is used to evaluate risks and failure consequences in terms of economic impacts. The economic impact analysis is a useful method in comparing the performance of various mine plans and slope designs. The risk analysis methodology thus provides a valuable indication of optimum slope design configurations and as such can be a great asset to the mine design process. This research paper aims to identify the key risks used as input to an open-pit mine plan in a feasibility stage and to define an approach to minimize these risks in order to achieve maximum economic benefit. The effectiveness of this approach will be evaluated by means of a case study which will attempt to achieve an optimum balance between value and risk, and to compare the magnitude of the economic impact of an individual risk with the probability of occurrence of said risk. The case study will utilise a risk map in order to define years with higher economic impacts as well as defining critical pit areas causing these risks, so as to identify areas requiring further investigation which will assist the mine in evaluating mitigation strategies in order to reduce overall risk.

Commodity markets are fundamentally cyclical, exposing mining companies to large swings in profitability during periods of economic boom and bust. Although this is well documented, companies continue to produce mine plans based on present market conditions that fail to acknowledge long-term metal price variability. The purpose of this thesis is to adapt McIsaac’s (2008) mathematical model for determining the most robust underground mining plan under conditions of metal price uncertainty for application in an open pit environment. An overview of conventional open pit algorithms is given to demonstrate that a circular analysis precludes the determination of an optimal solution when metal prices are uncertain. Under the proposed methodology, the optimal solution is achieved by selecting the cutoff grade and production rate under stochastic metal prices such that the net present value and probability of a positive net present value are maximized. The mathematical model was formulated with costs represented as a function of the level of production, rate of production or both. Revenues are achieved from either a mill, heap leach or stockpile process dependent on the level of production and metal price in the year of consideration. Metal prices are generated annually according to a stochastic model that balances short-term volatility with long-term trends. The compiled cash flow model determines the optimal net present value for a given production profile under input metal prices. The feasible area of production is established based on mine life, resource and financing constraints. Net present values are generated for a broad search grid, which converges towards a unimodal solution according to a golden search algorithm. The process is then repeated many times in order to identify the production profile at which the optimal solution is repeatedly reached. As a visual representation, the solutions are plotted on a bubble graph where the size of the bubble corresponds to the frequency of the solution; the largest bubble is associated with the optimal solution. The methodology is tested on two massive copper porphyry deposits, contained within a single claim, for which a Preliminary Economic Assessment has been completed.
Thesis (Master, Mining Engineering) -- Queen's University, 2010-02-08 22:07:52.331

Mining operations exploit mineral deposits, processing a portion of the extracted material to produce salable products. The concentration of valuable commodities within these deposits, or the grade, is heterogeneous. Not all material has sufficiently high grades to economically justify processing. Cut-off grade is the lowest grade at which material is considered ore and is processed to create a concentrated commodity product. The choice of cut-off grade at a mining project can be varied over time and dramatically impacts both the operation of the mine and the economics of the project. The majority of literature and the accepted industry practices focus on optimizing cut-off grade under known commodity prices. However, most mining operations sell their products into highly competitive global markets, which exhibit volatile commodity prices. Making planning decisions assuming that a given commodity price prediction is accurate can lead to sub-optimal cut-off grade strategies and inaccurate valuations. Some academic investigations have been conducted to optimize cut-off grade under stochastic or uncertain price conditions. These works made large simplifications in order to facilitate the computation of a solution. These simplifications mean that detailed mine planning data cannot be used and the complexities involved in many real world projects cannot be considered. A new method for optimizing cut-off grade under stochastic or uncertain prices is outlined and demonstrated. The model presented makes use of theory from the field of Real Options and is designed to incorporate real mine planning data. The model introduces two key innovations. The first is the method in which it handles the cut-off grade determination. The second innovation is the use of a stochastic price model of the entire futures curve and not simply a stocastic spot price model. The model is applied to two cases. The first uses public data from a National Instrument 43-101 report. The second case uses highly detailed, confidential data, provided by a mining company from one of their operating mines.
Thesis (Master, Mining Engineering) -- Queen's University, 2012-04-30 22:36:51.257