Program: Graduate Research Achievement Day 2017

Full program for 2017 Graduate Research Achievement Day.https://digitalcommons.odu.edu/graduateschool_achievementday2017-18_programs/1001/thumbnail.jp

Produção de biodiesel a partir de microalgas heterotróficas

Orientadores: Telma Teixeira Franco, Lucas Antonius Maria van der WielenTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química e Delft University of Technology.Resumo: Esta tese descreve os resultados da pesquisa de doutorado executada na Universidade de Campinas e na Universidade Técnica de Delft, como parte do program de Doutorado de Dupla Titulação entre as duas universidades. O projeto de pesquisa foi desenvolvido em parceria com a Petrobras S. A., que proveu a maior parte do suporte financeiro assim como suporte técnico, com o objetivo de avaliar o potencial de microalgas heterotróficas para a produção de biocombustíveis. Microalgas têm gerado muito interesse devido a seu inquestionável potencial para produção de biomassa e lipídeos através de fotossíntese. Nas últimas duas décadas, a busca por novas fontes de bio-energia causou um salto na pesquisa científica sobre cultivo de microalgas, o que impulsionou rapidamente o estado da arte. Apesar disso, a produção em larga escala ainda enfrenta obstáculos significativos, que encarecem os custos de produção and impedem que as microalgas se tornem uma fonte viável de bioenergia. A maior limitação das microalgas autotróficas é a necessidade da luz para o crescimento e o inevitável efeito de auto-sombreamento que ocorre com o aumento populacional. Quando a cultura se torna mais densamente povoada, a luz não consegue atingir camadas mais profundas, consequentemente desacelerando o crescimento. Isto limita a biomassa a baixas concentraçoes e, consequentemente, aumenta os volumes de cultivo e a demanda de grande quantidade de energy para separação da água. Apesar de extensa bibliografia sobre microalgas ter sido produzida nas últimas duas décadas, apenas uma pequena fração dos estudos se focaram no potencial heterotrófico desses versáteis microorganismos. Microalgas heterotróficas utilizam carbono orgânico como fonte energética e estrutural, ao invés de absorver carbono da atmosfera. Nesta condição, as microalgas podem crescer sem limitações pela luz e alcançar altas concentrações de biomassa e lipídeos. Porém, o cultivo heterotrófico e autotrófico não são comparáveis, já que o primeiro necessita de uma fonte de carbono orgânica e o segundo absorve carbono atmosférico. A tecnologia e os custos associados a cada um dos processos diferem fortemente. O desenvolvimento do cultivo heterotrófico inicia com a seleção de cepas adequadas para a produção de biocombustíveis e outros produtos de interesse. Este ainda é um campo de pesquisa pouco explorado, já que o cultivo heterotrófico representa apenas uma pequena fração de toda a literatura sobre algas. No capítulo 2, cepas de microalgas foram avaliadas em relação a sua capacidade de crescimento heterotrófico e produção de lipídeos. Após a análise do crescimento e composição celular, potenciais aplicações comerciais foram sugeridas para cada espécie estudada, já que diferentes composições de biomassa e lipídeos podem ser adequadas a diferentes produtos, como combustíveis, alimentos e produtos químicos. Chlorella vulgaris CPCC 90 foi identificada como uma opção adequada para a produção de biodiesel devido ao seu alto conteúdo lipídico e alta produtividade. Uma cepa produtora de ácidos graxas omega-3 poliinsaturados foi identificada e um breve estudo de otimização foi conduzido para aumentar a produção do ácido graxo de alto valor agregado. Após a seleção da cepa mais adequada para a produção de bio-combustíveis, o próximo passo foi o desenvolvimento de um cultivo altamente produtivo. A maior vantagem do cultivo heterotrófico é a possibilidade de alcançar altas concentrações de biomassa e conteúdo lipídico e, consequentemente, maiores produtividades volumétricas. Porém, o acúmulo de lipídeos ocorre quando células de microalgas são expostas a certas condições limitantes, que afetam negativamente o crescimento da biomassa. Desta forma, as condições de cultivo devem ser equilibradas de modo a promover o crescimento da biomassa e aumentar o conteúdo lipídico. Inicialmente, cultivos em batelada alimentada foram avaliados quanto ao acréscimo na concentração de biomassa e teor de lipídeos. A separação do crescimento e acúmulo de lipídeos em dois diferentes estágios permitiu a obtenção de uma cultura altamente concentrada e com elevado teor lipídico. Os lipídeos resultantes foram extraídos da biomassa e convertidos a biodiesel. Os rendimentos totais dos processos de cultivo, extração e reação foram calculados e discutidos (Capítulo 3). Apesar do cultivo em batelada alimentada ter-se mostrado altamente produtivo, o cultivo contínuo tem o potencial de reduzir o tempo ocioso da planta e aumentar a produtividade global e, consequentemente, reduzir custos de produção. Porém, manter cultivos contínuos com altas concentrações celulares não é trivial. O equilíbrio entre a vazão específica e a concentração de biomassa é crucial para a manutenção de alta produtividade. Cultivos em batelada alimentada e contínuos foram comparados quanto às produtividades totais, e o efeito da vazão específica sobre a concentração e produtividade de biomassa foi estudado (Capítulo 4). Cultivos contínuos também permitem um melhor controle da qualidade do produto final. A vazão específica e outros parâmetros, tais como a razão de alimentação de Carbono e Nitrogênio, afetam significativamente a composição de biomassa e o perfil de ácidos graxos dos lipídeos intracelulares. Através da variação destes parâmetros sob regime estacionário, tanto o conteúdo lipídico como a composição de ácidos graxos foi afetadas. Através da modelagem destes efeitos, é possível otimizar o processo, de acordo com o produto lipídico desejado (Capítulo 5). A integração de processos com outros setores da indústria pode, potencialmente, aumentar a viabilidade da produção de biocombustíveis de microalgas. Como o cultivo heterotrófico exige grande disponibilidade de fontes de carbono baratas, a integração com a indústria de cana-de-açúcar é uma opção atraente. Existem também potenciais ganhos para a industria da cana-de-açúcar, já que um terço de suas emissões de carbono resulta da queima de grandes quantidades de diesel de origem fóssil em operações agrícolas e de transporte. A produção de biodiesel de microalgas heterotróficas a partir de substratos da cana-de-açúcar representa uma oportunidade de de substituir a utilização de combustível de origem fóssil e aumentar a renovabilidade das refinarias de cana-de-açúcar. No Capítulo 6, é proposto um modelo de integração em que o melaço da cana-de-açúcar, vapor e eletricidade gerados na biorefinaria de cana-de-açúcar são utilizados para a produção de biodiesel de microalgas. Os resultados das simulações mostraram que a viabilidade do modelo proposto depende ainda da maturação da tecnologia, assim como de fatores externos, tais como o preço do petróleo e políticas e incentivos favoráveis a tecnologias sustentáveis. Esta tese representa uma contribuição ao estado da arte do desenvolvimento de biocombustíveis e outros produtos a partir de microalgas heterotróficas, especificamente focado no uso de culturas com alta densidade celular. Oferece ainda uma visão geral de alguns dos desafios que devem ser superados e das mais importantes variáveis na obtenção de um processo altamente produtivo e economicamente viávelAbstract: This thesis summarizes the results of a doctoral research executed in the State University of Campinas and in the Technical University of Delft as part of the PhD Dual Degree Program between the two universities. The research project was designed in partnership with Petrobras S. A. (Brazilian Petroleum Corporation), which provided most of the financial support as well as technical cooperation, with the goal of evaluating the potential of heterotrophic microalgae for biofuels production. Microalgae have generated a lot of interest due to their undoubted potential for the production of biomass and lipids through photosynthesis. In the last two decades, the search for new bio-energy feedstocks created a boom in scientific research on microalgae cultivation, which has improved the state of art of the technology at a rapid pace. However, large scale production still faces significant bottlenecks, which increase manufacturing costs and prevent microalgae from becoming a feasible bioenergy source. The main limitation related to autotrophic microalgae is the need of light for growth and the inevitable self-shading effect with the increase in cell population. As the culture becomes more densely populated, the light cannot reach deeper layers, thus slowing down the growth. This limits biomass to low concentrations and, consequently, increases cultivation volumes and demands high amounts of energy for water separation. Although extensive research about microalgae has been produced in the last two decades, only a small fraction of the studies aimed at the heterotrophic potential of these versatile microorganisms. Heterotrophic microalgae utilize organic carbon as energy source and building blocks rather than absorbing carbon from the atmosphere. In such circumstances, they can grow without light limitations and achieve high biomass and lipid concentrations. Nevertheless, heterotrophic and autotrophic cultivations are hardly comparable, since the former requires an organic carbon feedstock and the latter absorbs carbon from the atmosphere. The costs associated with each process are remarkably different, as well as the technology involved. The development of the heterotrophic cultivation process starts with the selection of suitable strains for the production of biofuels and other products. This is still a poorly explored field of research, as heterotrophic cultivation represents only a small fraction of all literature about algae. In Chapter 2, strains of microalgae were evaluated on their capacity for heterotrophic growth and lipid production. After the analysis of growth characteristics and cell composition, potential commercial applications for each strain were suggested, as different biomass and lipid compositions may be suitable for different final products, from biofuels to food and chemicals. Chlorella vulgaris CPCC 90 was identified as a suitable option for biodiesel production due to its high lipid content and productivity. One polyunsaturated omega-3 fatty acid producing strain was identified and a short optimization study was performed in order to enhance the production of the high value added fatty acid. After selection of the most suitable strain for biofuels production, the next step was the development of a highly productive cultivation process. The greatest advantage of heterotrophic cultivation is the possibility of reaching high biomass concentrations and lipid contents and, consequently, high volumetric productivities. However, lipid accumulation occurs when microalgae cells are exposed to certain limiting conditions, which negatively affect biomass growth. Therefore, cultivation conditions must be balanced in order to promote biomass growth and increase lipid content. After identification of the most suitable strain for biofuels production, fed-batch strategies were evaluated as means of increasing biomass concentration and lipid content. Decoupling biomass growth and lipid accumulation in two different stages allowed the production of a highly concentrated culture with increased lipid content. The resulting lipids were extracted from the produced biomass and converted into biodiesel. The overall yields of cultivation, extraction and reaction processes were calculated and discussed (Chapter 3). Although fed-batch cultivation proved itself highly productive, continuous production can potentially reduce downtime operations and increase global productivity, consequently reducing production costs. Operating continuous cultivation at high cell concentrations such as in the fed-batch process, however, is not trivial. The balance between dilution rate and biomass concentration is crucial in order to maintain high productivities. Fed-batch and continuous cultures were compared in terms of overall productivities and the effect of dilution rates was evaluated over biomass concentration and productivity (Chapter 4). Continuous cultivation also allows a better control of the final product quality. Growth rates and other parameters, such as Carbon to Nitrogen feeding ratio, significantly affect biomass composition and the fatty acid profile of intracellular lipids. By varying these parameters in steady state cultivation, lipid content and fatty acid composition were affected. By modelling these effects, it is possible to optimize the process according to the desired lipid-based product (Chapter 5). Process integration with other industry sectors may potentially increase the feasibility of microalgae biofuels production. Since heterotrophic cultivation demands a large availability of cheap carbon feedstocks, integration with the sugarcane industry is an attractive option. There are potential gains for the sugarcane industry as well, since one third of their carbon emissions result from burning large quantities of fossil-based diesel in crops and transportation operations. The production of heterotrophic microalgae biodiesel from sugarcane feedstocks offers the possibility of replacing the fossil fuel utilization and increasing the overall renewability of the sugarcane biorefinery. In Chapter 6, an integration model is proposed in which molasses, steam and electricity of sugarcane biorefinery are used for the production of microalgae biodiesel. Simulation results showed that the feasibility of the proposed model depends on the further development of the technology, as well as on external factors, such as petroleum prices and sustainability-driven policies and incentives. This thesis represents a contribution to the state of the art on the development of biofuels and other products from heterotrophic microalgae, specifically focused on the use of high cell density cultures. It offers an overview of some of the challenges that need to be overcome and provide insights on the most important variables for achieving a highly productive and economically feasible processDoutoradoDesenvolvimento de Processos QuímicosDoutor em Engenharia Químic

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 327)

This bibliography lists 127 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during August, 1989. Subject coverage includes: aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, and flight crew behavior and performance

Energy Development for Sustainability

Recently, energy development has received significant attention through the promising results of technology development, experimentation, computational modeling, and validation. However, it remains a persistent challenge to produce the needed energy while significantly reducing the environmental effects, such as the emission of greenhouse gases, which lead to climate change. Moreover, technological and economic limitations may also hinder energy development for sustainability. This book entitled Energy Development for Sustainability covers technologies, products, equipment, and devices as well as energy services based on software and data protected by patents and/or trademarks. This book will serve as a collection of the latest scientific and technological approaches to various energy development initiatives for sustainability encompassing novel sonocatalytic application and integrated algal and sludge-based wastewater treatment system, energy storage, sustainable building, gas absorption, organosolv pretreatment, energy usage and CO2 emission in transportation, coal regulation for energy, solar photovoltaic system, torrefaction for fuel production, energy management system, clean energy incubator, biofuels from microalgae, and the influence of COVID-19 on climate change. Overall, this book addresses researchers, advanced students, technical consultants, as well as decision-makers in industries and politics. This book contains comprehensive overview and in-depth technical research papers addressing recent progress in the area of energy development for sustainability. We hope the readers will enjoy this book

Advanced Modeling and Research in Hybrid Microgrid Control and Optimization

This book presents the latest solutions in fuel cell (FC) and renewable energy implementation in mobile and stationary applications. The implementation of advanced energy management and optimization strategies are detailed for fuel cell and renewable microgrids, and for the multi-FC stack architecture of FC/electric vehicles to enhance the reliability of these systems and to reduce the costs related to energy production and maintenance. Cyber-security methods based on blockchain technology to increase the resilience of FC renewable hybrid microgrids are also presented. Therefore, this book is for all readers interested in these challenging directions of research

Engineering Modular Synthetic Microbial Consortia for Sustainable Bioproduction From CO2

Engineering of synthetic microbial consortia has emerged as a new and powerful biotechnology platform with enormous potential for the production of biobased commodity chemicals. In this dissertation, I have designed, constructed, and optimized a tripartite system in which three microbes of differentiated specializations can convert sunlight, carbon dioxide, and atmospheric nitrogen into desired molecules or materials. Specifically, Synechococcus elongatus, a photosynthetic cyanobacterium that exports sucrose, and Azotobacter vinelandii, a nitrogen-fixing bacterium that secretes ammonia, form a symbiotic foundation hypothesized to support a third producer specialist. The tripartite consortia were implemented using a novel experimental set-up for continuous culture and extensive optimization was carried out with insights and guidance from computational modeling of the system dynamics. As a clear and strong proof of concept, I demonstrated various realizations of this tripartite platform, employing producer specialist strains ranging from model microorganism Escherichia coli to widely used industrial chassis such as Corynebacterium glutamicum and Bacillus subtilis. This versatile and modular technology platform offers potential for bioproduction without environmentally or monetarily expensive nutrient inputs thereby a pathway towards sustainable manufacturing of a wide range of bio-products. As an important component of the effort of engineering the tripartite system described above, I also carried out genetic modifications of E. coli K-12, the most widely used microbial chassis in synthetic biology, to enable efficient utilization of sucrose. A multigene csc operon encoding non-PTS sucrose catabolism was randomly transposed into E. coli K-12 using Tn5 transposase. Isolates from the transposon library yielded a range of growth rates on sucrose, including some that were comparable to that of E. coli K-12 on glucose. Narrowness of the growth rate distributions, improved gene expression conferring faster growth compared to that of plasmids, and enhanced growth rate upon transduction into strains that underwent adaptive laboratory evolution indicate that efficient csc expression is attainable and not limiting to cellular growth. Transduction of a csc fast-growth locus into an isobutanol production strain also yielded high titer with significant sustainability benefits. This work demonstrated that random integration is a viable and effective strategy for optimizing heterologous expression within the context of cellular metabolism for certain desirable phenotypes. In the last part of my thesis, through life cycle assessment, I investigated multi-species algal polycultures, which are different yet related CO2-fixing microbial communities. Experimental studies have previously shown that algal polycultures can be designed to enhance biomass production, stability, and nutrient recycling compared to monocultures. However, it remains unclear whether these impacts of biodiversity make polycultures more sustainable than monocultures. I have conducted a comparative life cycle assessment which showed that when algae were grown in outdoor experimental ponds, certain bicultures improved the energy return on investment and greenhouse gas emissions substantially, compared to the best monoculture. Bicultures outperformed monocultures by performing multiple functions simultaneously (e.g., improved stability, nutrient efficiency, biocrude characteristics), which outweighed the higher productivity attainable by a monoculture. These results demonstrated that algal polycultures with optimized multi-functionality lead to enhanced life cycle metrics, highlighting the significant potential of ecological engineering for enabling future environmentally sustainable algal bio-refineries. Collectively, this dissertation demonstrates how CO2-fixing microbial communities may be engineered to enhance sustainability metrics compared to monocultures. By successfully engineering more sustainable bioproduction platforms, we move closer to a society with lower dependence on petrochemicals.PHDChemical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/163222/1/dcarruth_1.pd

Design and engineering of microreactor and smart-scaled flow processes

This book is a reprint of the special issue that appeared in the online open access journal Processes (ISSN 2227-9717) in 2013 (available at: http://www.mdpi.com/journal/processes/special_issues/smart-scaled_flow_processes)

A contribution to support decision making in energy/water sypply chain optimisation

The seeking of process sustainability forces enterprises to change their operations. Additionally, the industrial globalization implies a very dynamic market that, among other issues, promotes the enterprises competition. Therefore, the efficient control and use of their Key Performance Indicators, including profitability, cost reduction, demand satisfaction and environmental impact associated to the development of new products, is a significant challenge. All the above indicators can be efficiently controlled through the Supply Chain Management. Thus, companies work towards the optimization of their individual operations under competitive environments taking advantage of the flexibility provided by the virtually inexistent world market restrictions. This is achieved by the coordination of the resource flows, across all the entities and echelons belonging to the system network. Nevertheless, such coordination is significantly complicated if considering the presence of uncertainty and even more if seeking for a win-win outcome. The purpose of this thesis is extending the current decision making strategies to expedite these tasks in industrial processes. Such a contribution is based on the development of efficient mathematical models that allows coordinating large amount of information synchronizing the production and distribution tasks in terms of economic, environmental and social criteria. This thesis starts presents an overview of the requirements of sustainable production processes, describing and analyzing the current methods and tools used and identifying the most relevant open issues. All the above is always within the framework of Process System Engineering literature. The second part of this thesis is focused in stressing the current Multi-Objective solution strategies. During this part, first explores how the profitability of the Supply Chain can be enhanced by considering simultaneously multiple objectives under demand uncertainties. Particularly, solution frameworks have been proposed in which different multi-criteria decision making strategies have been combined with stochastic approaches. Furthermore, additional performance indicators (including financial and operational ones) have been included in the same solution framework to evaluate its capabilities. This framework was also applied to decentralized supply chains problems in order to explore its capabilities to produce solution that improves the performances of each one of the SC entities simultaneously. Consequently, a new generalized mathematical formulation which integrates many performance indicators in the production process within a supply chain is efficiently solved. Afterwards, the third part of the thesis extends the proposed solution framework to address the uncertainty management. Particularly, the consideration of different types and sources of uncertainty (e.g. external and internal ones) where considered, through the implementation of preventive approaches. This part also explores the use of solution strategies that efficiently selects the number of scenarios that represent the uncertainty conditions. Finally, the importance and effect of each uncertainty source over the process performance is detailed analyzed through the use of surrogate models that promote the sensitivity analysis of those uncertainties. The third part of this thesis is focused on the integration of the above multi-objective and uncertainty approaches for the optimization of a sustainable Supply Chain. Besides the integration of different solution approaches, this part also considers the integration of hierarchical decision levels, by the exploitation of mathematical models that assess the consequences of considering simultaneously design and planning decisions under centralized and decentralized Supply Chains. Finally, the last part of this thesis provides the final conclusions and further work to be developed.La globalización industrial genera un ambiente dinámico en los mercados que, entre otras cosas, promueve la competencia entre corporaciones. Por lo tanto, el uso eficiente de las los indicadores de rendimiento, incluyendo rentabilidad, satisfacción de la demanda y en general el impacto ambiental, representa un area de oportunidad importante. El control de estos indicadores tiene un efecto positivo si se combinan con la gestión de cadena de suministro. Por lo tanto, las compañías buscan definir sus operaciones para permanecer activas dentro de un ambiente competitivo, tomando en cuenta las restricciones en el mercado mundial. Lo anterior puede ser logrado mediante la coordinación de los flujos de recursos a través de todas las entidades y escalones pertenecientes a la red del sistema. Sin embargo, dicha coordinación se complica significativamente si se quiere considerar la presencia de incertidumbre, y aún más, si se busca exclusivamente un ganar-ganar. El propósito de esta tesis es extender el alcance de las estrategias de toma de decisiones con el fin de facilitar estas tareas dentro de procesos industriales. Estas contribuciones se basan en el desarrollo de modelos matemáticos eficientes que permitan coordinar grandes cantidades de información sincronizando las tareas de producción y distribución en términos económicos, ambientales y sociales. Esta tesis inicia presentando una visión global de los requerimientos de un proceso de producción sostenible, describiendo y analizando los métodos y herramientas actuales así como identificando las áreas de oportunidad más relevantes dentro del marco de ingeniería de procesos La segunda parte se enfoca en enfatizar las capacidades de las estrategias de solución multi-objetivo, durante la cual, se explora el mejoramiento de la rentabilidad de la cadena de suministro considerando múltiples objetivos bajo incertidumbres en la demanda. Particularmente, diferentes marcos de solución han sido propuestos en los que varias estrategias de toma de decisión multi-criterio han sido combinadas con aproximaciones estocásticas. Por otra parte, indicadores de rendimiento (incluyendo financiero y operacional) han sido incluidos en el mismo marco de solución para evaluar sus capacidades. Este marco fue aplicado también a problemas de cadenas de suministro descentralizados con el fin de explorar sus capacidades de producir soluciones que mejoran simultáneamente el rendimiento para cada uno de las entidades dentro de la cadena de suministro. Consecuentemente, una nueva formulación que integra varios indicadores de rendimiento en los procesos de producción fue propuesta y validada. La tercera parte de la tesis extiende el marco de solución propuesto para abordar el manejo de incertidumbres. Particularmente, la consideración de diferentes tipos y fuentes de incertidumbre (p.ej. externos e internos) fueron considerados, mediante la implementación de aproximaciones preventivas. Esta parte también explora el uso de estrategias de solución que elige eficientemente el número de escenarios necesario que representan las condiciones inciertas. Finalmente, la importancia y efecto de cada una de las fuentes de incertidumbre sobre el rendimiento del proceso es analizado en detalle mediante el uso de meta modelos que promueven el análisis de sensibilidad de dichas incertidumbres. La tercera parte de esta tesis se enfoca en la integración de las metodologías de multi-objetivo e incertidumbre anteriormente expuestas para la optimización de cadenas de suministro sostenibles. Además de la integración de diferentes métodos. Esta parte también considera la integración de diferentes niveles jerárquicos de decisión, mediante el aprovechamiento de modelos matemáticos que evalúan lasconsecuencias de considerar simultáneamente las decisiones de diseño y planeación de una cadena de suministro centralizada y descentralizada. La parte final de la tesis detalla las conclusiones y el trabajo a futuro necesario sobre esta línea de investigaciónPostprint (published version

Guidelines to the evaluation of selectively mined, open pit gold deposits during the exploration stage of mine creation

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