Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2017-03-23T11:27:35Z No. of bitstreams: 2 Dissertação - Raphael Silva Tomáz - 2016.pdf: 2331721 bytes, checksum: a9647e44c4843954a331dd4514b39b2c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-03-23T11:27:51Z (GMT) No. of bitstreams: 2 Dissertação - Raphael Silva Tomáz - 2016.pdf: 2331721 bytes, checksum: a9647e44c4843954a331dd4514b39b2c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-03-23T11:27:52Z (GMT). No. of bitstreams: 2 Dissertação - Raphael Silva Tomáz - 2016.pdf: 2331721 bytes, checksum: a9647e44c4843954a331dd4514b39b2c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-03-22 / The importance of pigments to human civilization is evident and well documented. Although these materials were discovered many years ago, research continues to this day, industries often require new colors and more reproducible and stable shades. The selection of raw materials is of paramount importance in order to acquire high quality mineral pigments, color luminescence and purity, free of chemical contaminants. Mineral pigments have been gaining commercial acceptance as a result of growing ecological awareness, which aims to reduce the environmental impact of synthetic production methods. The most common mineral pigments are iron oxides, manganite, chromite, quartz, feldspar, monazite, zirconite, titanite muscovite and biotite. Most of the iron production in Brazil, whether processing the hematite or magnetite, is done by flotation and magnetic separation. Flotation impairs the use of oxides for purposes other than steel production due to the huge amount of chemicals, mainly surfactants, involved in this step. Jigging is a process of hydraulic separation consisting of the repeated expansion and vertical contraction of a bed of particles by the pulsating movement of water. The result of this movement is the stratification of the material. Anglo American Phosphates from Brazil has a tailings production of 2 Mt (million tons) with barite contents of 6% and magnetite about 40%, and this material is sent in full to the tailings dam. The removal of the magnetite from the phosphate production process leads to three major gains: the first would be the reduction of material sent to the flotation steps of barite and apatite, the second is the generation of a material that could be used for other purposes, such as The production of pigments, with the generation of a co-product and the third would be the reduction of material sent to the tailings dam, thus avoiding the construction of new dams and reducing environmental impacts. The enrichment of the reject by the jigging for the extraction of this mineral is justified due to the specific mass difference of the minerals involved, together with the simplicity of operation and its low operating cost. Concentration by gravimetric methods, based on the density difference between magnetite and quartz, may be an option for the use of the reject of the phosphate rock production for the production of high-grade magnetite to be used in the production of pigments. The results show that it is possible to separate magnetite for the purpose of producing pigments in certain parameters of jigue operation. / A importância dos pigmentos para a civilização humana é evidente e bem documentada. Embora, estes materiais tenham sido descobertos há tantos anos as pesquisas continuam até hoje, pois as indústrias exigem frequentemente novos tons e cores cada vez mais reprodutíveis e estáveis. A seleção das matérias-primas é de suma importância para se adquirir pigmentos minerais de alta qualidade, luminescência de cor e pureza, ou seja, livre de contaminantes químicos. Os pigmentos minerais vêm ganhando aceitação comercial em consequência da crescente conscientização ecológica, que visa diminuir o impacto ambiental provocado pelos métodos sintéticos de produção. Os pigmentos minerais mais comuns são os óxidos de ferro, manganita, cromita, o quartzo, o feldspato, monazita, zirconita, titânia e micas. A maior parte da produção de ferro do Brasil, seja processando a hematita quanto a magnetita, é feita por flotação e separação magnética. A flotação prejudica a utilização dos óxidos para outros fins além da produção de aço devido à enorme quantidade de produtos químicos, principalmente surfactantes, envolvidos nesta etapa. A jigagem é um processo de separação hidráulica que consiste da repetida expansão e contração vertical de um leito de partículas pelo movimento pulsante de água. O resultado desse movimento é a estratificação do leito. A Anglo American Fosfatos do Brasil possui uma produção de rejeito de 2 Mt (milhões toneladas) com teores de barita de 6% e magnetita por volta de 40%, sendo esse material enviado integralmente para a barragem de rejeito. A retirada da magnetita do processo de produção de fosfato trás três grandes ganhos: o primeiro seria a redução de material enviado para os passos de flotação da barita e apatita, o segundo é a geração de um material que poderá ser utilizado para outros fins, como a produção de pigmentos, com a geração de um co-produto e o terceiro seria a redução de material enviado para a barragem de rejeito, evitando assim a construção de novas barragens e reduzindo os impactos ambientais. O enriquecimento do rejeito pela jigagem para a extração desse mineral se justifica devido à diferença de massa específica dos minerais envolvidos, aliado a simplicidade de operação do equipamento e pelo seu baixo custo de operação. A concentração por métodos gravíticos, baseada na diferença de densidade entre a magnetita e o quartzo, pode ser uma opção para o aproveitamento do rejeito da produção de rocha fosfática para a produção de magnetita de alto teor para ser utilizada na produção de pigmentos. Os resultados mostram que é possível a separação da magnetita para fins de produzir pigmentos em determinados parâmetros de operação do jigue.

O Brasil é um dos grandes produtores mundiais de minério de ferro e exporta a maior parte da sua produção. No comércio internacional é importante assegurar a comparabilidade dos resultados analíticos obtidos em diferentes laboratórios. Uma variação de 0,1 % na média do teor de ferro pode aumentar ou diminuir em muito o valor de um grande carregamento de minério. Assim, os sistemas de garantia da qualidade dos laboratórios necessitam de materiais de referência. Este trabalho estudou a preparação de um lote de minério de ferro (pelotizado) como material de referência, certificando os teores de vários constituintes por meio de um programa interlaboratorial. Treze laboratórios participaram do programa e dezoito componentes do minério tiveram seus teores certificados: Fetotal (65,1%), SiO2 (2,76%), Al2O3 (0,46%), TiO2 (0,056%), P (0,026%), S (0,003%), MnO (0,094%), CaO (3,31%), MgO (0,043%), K2O (0,013%), Ba (0,004%), Zn (13 mg/kg), Cu (10 mg/kg), Co (12 mg/kg), Cr (56 mg/kg), Pb (15 mg/kg), Ni (14 mg/kg), V (48 mg/kg). / Brazil is one of the great worldwide iron ore producers and exports most of its production. In the international trade it is important to make sure the comparison of the analytical results among different laboratories. A variation of 0,1% in the average of the iron content can increase or decrease the value of a large ore shipment. Thus, the quality guarantee systems of the laboratories need certified reference materials. The aim of this work was the preparation an amount of iron ore (pellets) as reference material, being certified content of some constituents through an interlaboratory program. Thirteen laboratories participated of the program and eighteen components of the ore had its content certified: Fetotal (65,1%), SiO2 (2,76%), Al2O3 (0,46%), TiO2 (0,056%), P (0,026%), S (0,003%), MnO (0,094%), CaO (3,31%), MgO (0,043%), K2O (0,013%), Ba (0,004%), Zn (13 mg/kg), Cu (10 mg/kg), Co (12 mg/kg), Cr (56 mg/kg), Pb (15 mg/kg), Ni (14 mg/kg), V (48 mg/kg).

A análise de imagens automatizada tem atualmente importante papel no setor mineral, devido à rapidez das análises e à confiabilidade dos resultados. A técnica pode ser realizada por meio de imagens adquiridas em microscópio eletrônico de varredura, geralmente associada a microanálises químicas por EDS. Estas analises podem ser realizadas em diversas etapas de um empreendimento mineiro: no auxílio à exploração, lavra (blendagens), processos de beneficiamento (associação mineral), estudos de gênese e controles de mineralização. Essa técnica permite a análise estatística de grande número de partículas/dados, fornecendo informações de composição mineralógica, química mineral, partição de elementos, associações minerais incluindo liberação de fases de interesse, entre outros. Este estudo investiga a aplicabilidade da análise de imagens automatizada em amostras de minério de ferro, com base em diferentes procedimentos de preparação de amostras e rotinas de análise avaliadas por meio do sistema MLA. Um minério de ferro foi escolhido por se tratar de um minério já bastante estudado e bem documentado na bibliografia e que mostra, em geral, mineralogia e texturas simples e repetitivas facilitando a análise dos resultados obtidos com os diferentes procedimentos e rotinas aplicadas. Além disso, o minério de ferro apresenta fases minerais com significativas diferenças de peso específico, o que pode acarretar em maiores dificuldades em termos de amostragem e preparação de amostras. / The automated image analysis has an important role in the mineral industry due to the quickly analysis and the results reliability. The technique can be applied using images from a scanning electron microscope associated usually coupled with chemical microanalysis from an EDS system. These analyses are carried out in many stages of a mining project helping mineral exploration, mining (blending), mineral processing (mineral association), genetic studies and mineralization control. This technique allows a statistic analysis of a large numbers particles and data, providing information of mineralogical composition, mineral chemistry, elemental distribution, mineral associations, phase and spectra liberation and others. This study sets the applicability of automated image analysis of an iron ore sample with diverse preparation procedures and analysis routines, which were evaluated by the MLA system. An iron ore sample was chosen because it is a familiar and well-documented ore in the literature, that usually shows simple textures and mineralogy which makes easier the interpretation of results by a diversity of preparation procedures and analysis routines. Furthermore, the iron ore shows mineral phases with significant differences in specific gravity resulting in more difficulties in sampling and preparation procedures due to potential density segregation.

[pt] O presente trabalho visou avaliar o processo de eletroflotação de partículas finas e ultrafinas de minério de ferro com o uso de um biossurfactante extraído da bactéria Rhodococcus Opacus. Foram realizados estudos de caracterização de um minério de ferro (análise granulométrica, difração de raios - X e fluorescência de raios - X). Através das medições de espectroscopia no infravermelho foi possível identificar uma provável interação do biossurfactante com a hematita, o espectro após a interação mostrou grupos funcionais característicos do biossurfactante (NH, CH2, C=O, COO-e PO2-). As medidas de potencial zeta mostraramuma possível interação eletrostática entre a hematita e o biossurfactante, a reversão de carga mudou do pH 5,3 para 3,5 após a interação. As medidas de ângulo de contato sugeremque após a interação, a hematita pode ter se tornado mais hidrofóbica, alterando o ângulo de contato de 40 graus para 60 graus. As medidas de tensão superficial foram realizadas para determinar as propriedades físico-químicas do biossurfactante. De acordo com os resultados, o biossurfactante apresentou características tensoativas, reduzindo a tensão superficial de 71 mN/m para 40 mN/m em 25 mg/L de biossurfactante.Finalmente, foram realizados testes de eletroflotação com duas frações granulométricas de minério de ferro (-38+20micrometro e -20 micrometro) para avaliar o pH (3-11), a concentração do biossurfactante (50-800 mg/L), a densidade de corrente (5,28-16mA/cm2) e a agitação da solução (300-700 rpm). Segundo os resultados obtidos, o aumento do pH prejudicou a recuperação metalúrgica e o teor de ferro. Os melhores resultados ocorreram em pH 3, esse comportamento pode ser atribuído a interações eletrostáticas que ocorrem nessa faixa de pH. O aumento da concentração do biossurfactante favoreceu a recuperação metalúrgica e o teor de ferro, este comportamento se manteve até 300 mg/L, acima deste valor ocorreu um declínio provocado provavelmente pela formação de micelas. O aumento da densidade de corrente também favoreceu a recuperação metalúrgica e o teor de ferro. Para a amostra com faixa granulométrica de -38+20 micrometro a recuperação metalúrgica máxima foi em torno de 83 porcento e teor de ferro de 59 porcento, e a amostra com granulometria inferior a 20 μmapresentou uma recuperação metalúrgica e teor de Fe máxima de aproximadamente de 98 porcento e 64 porcento respectivamente. Dessa forma, os resultados obtidos mostram um potencial uso da técnica de eletroflotação na recuperação de partículas finas e ultrafinas de minério de ferro, utilizando o biossurfactante extraído da bactéria Rhodococcus opacus. / [en] This work aimed to evaluate the electroflotation process of fine and ultrafine iron ore particles using biosurfactant extracted from Rhodococcus Opacus bacteria. Characterization studies of iron ore were carried out (particle size analysis, X-ray diffraction and X-ray fluorescence). Through infrared spectroscopy measurements it was possible to identify a possible interaction of the biosurfactant with the mineral, the hematite spectrum after the interaction showed characteristic functional groups of the biosurfactant (NH, CH2, C=O, COO-e PO2-).The measurements of zeta potential suggest a possible electrostatic interaction between the hematite and the biosurfactant, by shifting the isoelectric point from 5.3 to 3.5.Contact angle measurements suggest that after interaction, hematite may have become more hydrophobic, changing the contact angle from 40 degrees to 60 degrees.Surface tension measurements were performed to determine the physico-chemical properties of the biosurfactant. According to the results, the biosurfactant showed tensioactive characteristics, reducing the surface tension from 71 mN/m to 40 mN/m in 25 mg/L of biosurfactant, the formation of micelles occurred from 300mg/L of biosurfactant. Finally, electroflotation tests were performed with two size fractions of iron ore (-38+20 micrometre and -20 micrometre) to evaluate the pH (3-11), biosurfactant concentration (50-800 mg/L), current density (5.28-16mA/cm2) and solution agitation (300-700 rpm). According to the results obtained, the increase in the pH impaired the metallurgical recovery and iron grade. The best results occurred at pH 3, this behavior can be attributed to electrostatic interactions that occur in this pH range. The increase of the biosurfactant concentration favored metallurgical recovery and the iron grade, this behavior remained up to 300 mg/L, above this value occurred a decline probably caused by the formation of micelles. The increase in current density also favored metallurgical recovery and iron content. For the sample with particle size range from -38+20 micrometre the maximum metallurgical recovery was around 76 percent and 59 percent iron grade and the sample with particle size from -20 micrometre the maximum metallurgical recovery and grade of Fe were around 90 percent and 64 percent, respectively. The results obtained show a potential use of the electroflotation technique in the recovery of fine and ultrafine iron ore particles, using the biosurfactant extracted from the Rhodococcus opacus bacterium.

[pt] Pelo presente trabalho, buscou-se desenvolver uma ferramenta capaz de analisar e otimizar o uso de pelotas de minério de ferro em processos tradicionais de redução direta do tipo forno cuba. A criação de um modelo termoquímico do processo MIDREX foi proposta e elaborada dentro da PUC-Rio, levando-se também em conta alguns aspectos cinéticos relativos à redução dos minérios e à carburização do ferro-esponja, bem como alguns parâmetros operacionais. Este modelo foi subseqüentemente adaptado para interagir com um segundo modelo termoquímico de forno elétrico a arco da RS Consultants, representando assim a cadeia de fabricação de aço líquido primário pela rota redução direta - forno elétrico a arco. Para o gerenciamento computacional do processo de otimização e interação com os dois modelos acima citados, desenvolveu-se, adicionalmente, um terceiro modelo, o qual foi designado neste trabalho como modelo GESTOR. Um máximo uso de ferro-esponja ― e de pelotas, conseqüentemente ― é objetivado sempre que possível, sob determinadas condições operacionais pré-estabelecidas. A avaliação econômica destes processos foi embasada em conceitos de valor de uso. Alguns resultados são apresentados neste trabalho, para demonstrar a efetividade e o poder de análise da ferramenta e espera-se que os profissionais da Samarco possam fazer uso deste instrumento de trabalho, dando o devido suporte à tomada de decisão à comercialização e ao desenvolvimento de produtos existentes ou novos. / [en] The study at issue searched for developing an innovative tool able to effectively analyze and optimize the industrial usage of iron ore pellets undergoing traditional gas-based direct reduction processes. The creation of a thermochemical model for MIDREX process was proposed and carried out by PUC-Rio, taking into account relevant characteristics related to DRI carburization and reduction kinetics, as well as some important operating parameters. Subsequently, this model was adapted in order to interact with a second thermo-chemical model owned by RS Consultants and able to represent an electric arc furnace operation. In this sense, it has been possible to represent thereby the iron and steelmaking route based on direct reduction and electric arc furnace. For the computational management of the optimization methodology and interaction involving the two models above-mentioned, a third model was developed and referred to as GESTOR model. It was built to maximize the DRI usage ¯ and pellets utilization, consequently ¯ respecting certain operating conditions previously established. Economic assessments shall be made premised upon value in use concepts. Some results are shown in this study, based on a hypothetical scenario, aiming at proving the effectiveness of this tool. Its adoption by Samarco´s experts is expected as an important supportive methodology to help them to make decisions properly concerning both marketing strategies and product development activities.

[pt] As pelotas de minério de ferro são produzidas a partir de um processo de aglomeração de finos de minério denominado pelotização, e possuem granulometria adequada para utilização em fornos siderúrgicos. Nesta dissertação dois fenômenos associados às superfícies das pelotas foram estudados: a formação de trincas e a presença de recobrimento (coating). Durante a pelotização, as pelotas são submetidas a diversos esforços compressivos e mudanças bruscas de temperatura. Desta forma, são geradas trincas em sua superfície, que são prejudiciais à resistência e ao desempenho nos fornos de redução. Já durante o processo de redução pode ocorrer a formação de pontes de ferro entre as pelotas, que se aglomeram formando clusters que comprometem o fluxo de gases no interior dos fornos. Este problema pode ser minimizado recobrindo as pelotas com uma mistura a base de óxidos de magnésio, o coating, que inibe a formação das pontes. Tendo em vista a importância de caracterizar trincas e coating na superfície das pelotas, a presente dissertação desenvolveu metodologias de aquisição, processamento e análise digital de imagens adquiridas com um estereoscópio. Foram desenvolvidos porta-amostras ajustáveis que permitiram a aquisição de imagens 2D de pelotas aproximadamente esféricas de diferentes tamanhos, cobrindo a maior parte da superfície e evitando a sobreposição de regiões de análise. A rotina de análise de trincas comparou dois métodos de segmentação e forneceu atributos como espessura média, fração de área e comprimento. A rotina de análise de coating utilizou segmentação por limiarização e mediu a fração de área ocupada em cada pelota. O uso dos porta-amostras foi fundamental para o sucesso do procedimento de aquisição. As rotinas de análise de trincas ou de coating se mostraram robustas para diferentes amostras. / [en] Iron ore pellets are produced from an ore fines agglomeration process called pelletizing, and are suitable for use in steel furnaces. In this dissertation two phenomena associated with the pellet surfaces were studied: crack formation and the presence of coating. During pelletizing, the pellets undergo various compressive forces and sudden changes in temperature. In this way, cracks are generated on its surface, which are detrimental to strength and performance in reduction furnaces. Already during the reduction process the formation of iron bridges can occur between the pellets, which clump forming clusters that compromise the flow of gases inside the furnaces. This problem can be minimized by coating the pellets with a magnesium oxide coating, which inhibits the formation of bridges. Given the importance of characterizing cracks and coating on the surface of the pellets, this dissertation developed methodologies for acquisition, processing and digital analysis of images acquired with a stereoscope. Adjustable sample holders were developed which allowed the acquisition of 2D images of approximately spherical pellets of different sizes, covering most of the surface and avoiding overlapping analysis regions. The crack analysis routine compared two segmentation methods and provided attributes such as mean thickness, area fraction and length. The coating analysis routine used threshold segmentation and measured the fraction of area occupied in each pellet. The use of the sample holders was fundamental to the success of the acquisition procedure. Crack analysis or coating routines were robust for different samples.

Thesis (MBA)--Stellenbosch University, 2007. / ENGLISH ABSTRACT: Human resources budgeting at Sishen mine had been done, for as long as the researcher has been employed at the mine, according to history as well as according to the demands of the financial situation. Consequently, human resources shortages have been corrected by external labour which is often more expensive than internal labour. During the annual budgeting period when top management applies pressure to cut costs, the operations budget is easy to defend. With the help of Excel spreadsheets or maintenance management systems, maintenance managers can present strong arguments for not cutting the operations budget. Budget deficits are then easily corrected by means of negative adjustments to the human resources budget. This research will explore the issue of whether a tool exists to calculate the human resources budget scientifically. A target was set to develop a tool or model for human resources budgeting or to investigate whether such a tool does not already exist. A literature survey was done to determine world best practices regarding the calculation of human resources budgeting. The literature studied guided the researcher to a computerised maintenance management system (CMMS) and it was found that Sishen already has one of the best (SAP) in place. Sishen even has a process (Routine Work Management or RWM) in place which helps to get all maintenance information into SAP to make the necessary information available for effective maintenance. It was further found that SAP, which has been used by the mine for several years, can already provide the human resources requirements for any future period. The RWM process which helps to get information in and out of SAP has been in use for some time already. Unfortunately the process was poorly executed and the information is not reliable. This statement is supported by the internal (Kirstein, 2006) and external (Aurea, 2006) audits done at the mine during 2006. The external audit was done by Aurco (2006). The author concluded that Sishen has a tool but not a strategy to utilise RWM successfully. One of the reasons why RWM was poorly executed was the fact that there is a lack of support from the people in the workplace. These individuals claim that they were not consulted when RWM was introduced at the mine and as a result they did not buy in. A proper change management process was not followed and the employees suspected that RWM was implemented to play policeman or to measure how much spare time they have and reduce the workforce accordingly, as in the case of the Prometheus project. Consequently they admit to manipulating RWM's measured outcomes, ignoring it or deliberately undermining it. They added that RWM is easy to manipulate and perceived it as a farce by many of the participants, A decision was taken to use the Kotter change management process to run a project to get RWM to the required level. Kotter's eight steps for successful large-scale change can be utilised with great success to achieve the required changes. After a brainstorming session and from the recommendations of the two audits a list of ideas was compiled. These ideas should help to get RWM to a level where human resources requirements can be drawn from SAP for any period in the future. Although the research was aimed at getting human resources budgeting from SAP, it will also have other advantages. The ratio between planned and unplanned maintenance will be better because RWM will ensure better maintenance / AFRIKAANSE OPSOMMING: Mannekragbegroting op Sishen-myn is, vir solank die navorser deel is van die myn, gedoen volgens die behoeftes van die verlede asook volgens wat deur die finansiele situasie toegelaat is. Gevolglik het dit dikwels gebeur dat die tekorte aan mannekrag aangevul is met huurarbeid wat dikwels duurder is as eie mannekrag. Tydens die begrotingsrondte kan die geld wat aangevra word vir die instandhouding van die toerusting goed beveg word omdat die instandhoudingspersoneel waterdigte argumente kan aanvoer oor hoe die begroting bereken is. Begrotingstekorte word gevolglik maklik reggestel met negatiewe aanpassings op die mannekragbegroting. Hierdie studie gaan die bestaan ondersoek van 'n gereedskapstuk of model om die mannekragbegroting wetenskaplik te kan bereken. Daar is 'n doelwit gestel om 'n model te ontwikkel vir mannekragberekening of om vas te stel of daar nie reeds iets bestaan nie. 'n Literatuurstudie is gedoen om vas te stel wat wereldwye beste standaarde ten opsigte van mannekragberekening is. Dit het die navorser gelei na gerekenariseerde instandhoudingsbestuurstelsels (CMMS) en daar is bevind dat Sishen reeds een van die beste stelsels gebruik (SAP). Sishen het selfs 'n proses ("Routine Work Management" of RWM) om alle instandhoudingsinligting in SAP te kry sodat die regte inligting weer beskikbaar kan wees vir effektiewe instandhouding. Daar is verder bevind dat SAP, wat reeds vir verskeie jare in gebruik is, enige tydperk in die toekoms se mannekragbehoeftes kan bepaal. Die RWM-proses wat moet help om inligting in en uit SAP te kry, is ook reeds geruime tyd in gebruik, maar ten spyte daarvan word die proses afgewater en is die inligting nie betroubaar nie. Hierdie stelling is bewys deur middel van twee ouditte wat in 2006 op RWM gedoen is. Die een audit was 'n interne audit terwyl die ander deur die maatskappy Aurea gedoen is. Die afleiding kon dus gemaak word dat daar wel 'n gereedskapstuk is, maar dat geen strategie bestaan om dit effektief te gebruik nie. Een van die redes waarom RWM as 'n afgewaterde proses beskryf kan word, is 'n gebrek aan ondersteuning deur die mense in die werksplek. Die mense beweer dat hulle nie geken is ten tye van die bekendstelling van RWM nie en hulle het dus nie ingekoop nie. Die afleiding is gemaak dat daar nie goeie veranderingsbestuur toegepas is toe RWM aan die myn bekendgestel is nie. Die werknemers het vermoed dat RWM ingestel is om hulle te polisieer of te bepaal hoeveel vrye tyd hulle het en die werksmag dienooreenkomstig af te skaal, soos in die geval van die Prometheusprojek. Gevolglik het hulle erken dat hulle die RWM se uitkomste gemanipuleer het, dit geignoreer het, of doelbewus ondermyn het. Hulle het bygevoeg dat RWM maklik gemanipuleer kan word en dat baie dit as 'n klug beskou. Daar is besluit om die Kotter-model te gebruik om 'n projek te loods om RWM op die vereiste standaard te kry. Dit word as die geskikste model beskou om die nodige veranderingsbestuur toe te pas. 'n Lys van idees is opgestel na aanleiding van 'n dinkskrumsessie met die werknemers asook van voorstelle wat in die twee ouditverslae gemaak is. Herdie idees moet RWM in plek kry sodat mannekragbehoeftes vir enige tydperk in die toekoms vanuit SAP verkry kan word. Alhoewel die navorsing daarop gemik was om mannekragbegroting vanuit SAP te bekom, hou dit ook 'n ander voordeel in, naamlik 'n beter verhouding van beplande tot onbeplande instandhouding omdat goeie RWM-prosedures beter instandhouding en gevolglik beter beskikbaarheid gaan verseker.

Thesis (MBA)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: Early in 2001, Thabazimbi Iron Ore mine embarked upon a Leadership and Culture Change strategy. This program was one of the five strategic goals decided upon as part of the strategic drive to improve the performance of the business. A formal, structured implementation plan was crafted in house to approach the initiative. The plan was based on the literature of a number of prominent authors in the fields of leadership, competence theory and change management. The plan is built around a model known as the "Thabazimbi Thumbprint" which is primarily based on the work of Bernard Bass and Bruce Avolio in the field of Transfomational Leadership, and Dr Jay Hall's research and literature on the Competence Process. The primary aims of the implementation of this strategy at the mine were to: • Address the damage done to morale and commitment levels by repeated downsizing and the threat of mine closure. • Establish a high performance team culture. • Remove blockages to performance and the development of human potential. The strategy and implementation plan of the mine is compared against current literature within the fields of leadership and change management and significant similarities are observed. Even though the implementation of this initiative has only been running for some 2 years and is far from complete, a number of significant improvements have been made in terms of collaboration, commitment, trust in management and the reduction of conflict. In addition the performance of the mine in the field of safety and health has vastly improved, the production process is currently stable and targets are met, operating costs have reduced by 4% year on year and the current life of mine has been extended to 10 years. The writer has been the Engineering Manager at the mine from December 2001 and has been responsible for the implementation of this strategy within the Engineering department of the mine. The strategy and implementation plan serves as an example of a fully integrated and comprehensive approach to implementing such an initiative, while remaining simple and practical. The author identifies a number of deficiencies within the strategy used by the mine and makes some recommendations to improve the process that should be considered with respect to the future implementations of this type of initiative. / AFRIKAANSE OPSOMMING: Thabazmbi Ysterertsmyn met 'n Leierskap en Kultuur veranderingstrategie aan die begin van 2001 begin. Die program was deel van vyf strategiese besigheidsdoelwitte wat daarop gemik was om die kern te vorm van die strewe na 'n verbeterde prestasie van die besigheid. 'n Formele, gestruktureerde implementeringsplan is deur die myn ontwikkel vir die daarstelling van die inisiatief. Die plan was op die literatuur van prominente skrywers in die leierskap, bevoegtheidsteorie en veranderingsbestuur rigtings gebaseer. Die plan is gebou op 'n model bekend as die "Thabazimbi Thumbprint" en is gebaseer op die werk van Bernard Bass en Bruce Avolio in die veld van Transformasie Leierskap, en op Dr Jay Hall se navorsing en literatuur oor die "Competence Process". Die primere mikpunte van die implementeering van die strategie op die myn was die volgende: • Om die skade wat herhaalde afskalings en dreigemente van toemaak aan die moraal en toegewydheid van die werksmag gedoen het, aan te spreek. • Om 'n hoe presterende spankultuur te vestig. • Om die blokasies wat onderprestasie veroorsaak en die onderontwikkeling van menslike potensiaal uit die weg te ruim. Die strategie en implementeringsplan is met huidige literatuur in die leierskap- en kultuurveranderingsrigtings vergelyk. Daar is 'n groot mate van ooreenstemming waargeneem. Hoewel hierdie inisiatief maar slegs twee jaar aan die gang is en nog ver van klaar is, is daar al reeds 'n merkwaardige verbetering te bespeur in terme van samewerking, toewyding, die vertroue in bestuur en die vermindering van konflik. Bo en behalwe eersgenoemde pluspunte is daar ook 'n groot verbetering wat betref die gesondheid- en veiligheidsfaktore op die myn. Die produksieproses is stabiel en doelwitte word behaal. Die operasionele kostes is met 4% per jaar besnoei en die huidige lewe van die myn is verleng tot 10 jaar. Die skrywer is die Ingenieursbestuurder van die myn vanal Desember 2001 en was verantwoordelik vir die implementering van die strategie binne die ingenieursafdeling van die myn. Die strategie en implementeringsplan dien as 'n voorbeeld van 'n volledig geintegreerde benadering tot implimentering van so 'n inisiatief, terwyl dit prakties en eenvoudig bly. Die skrywer identifiseer 'n aantal leemtes binne die strategie soos deur die myn gebruik en maak aanbevelings vir die verhetering van die proses wat in die toekoms in ag geneem behoort te word in die implimentering van hierdie tipe inisiatiewe.

Green national accounts are a complement to the more traditional GDP measure which includes natural capital and the depreciation and regeneration of natural capital. The United Nations have developed an international standard model, the System of Environmental-Economic Accounting, for valuing natural resources within the green national accounts. The method is based on forecasts of future streams of expected incomes from the resource. This study aims to find out whether the valuation method used to forecast future incomes from iron ore and timber according to the international standard is consistent with the actual outcomes. In Sweden, previous studies have been made to develop green national accounts from the 1800s onward. By using the United Nations’ current and previous valuation methods and performing calculations on historical resource rents it is possible to evaluate how well the methods can estimate true future values. This study shows that both valuation methods systematically misestimate the future income streams from both resources. / Gröna nationalräkenskaper är ett komplement till det mer traditionella BNP-måttet som även tar hänsyn till bland annat naturkapitalet och dess förslitning. FN har utvecklat en internationell standardmodell för gröna nationalräkenskaper, System of Environmental-Economic Accounting (SEEA), där en rekommenderad värderingsmetod för naturkapital finns angiven. Värderingsmetoden är baserad på framtida, förväntade, inkomstflöden från naturresursen. Den här studiens syfte är att ta reda på om värderingsmetoden för att förutse framtida intäkter för järnmalm och skog enligt den internationella standarden stämmer överens med de faktiska utfallen. I Sverige har tidigare studier gjorts för att utveckla gröna nationalräkenskaper från 1800-talet och framåt. Genom att använda FN:s nuvarande och tidigare rekommenderade värderingsmetoder för naturresurser och göra beräkningar på historiska vinster från naturresursen kan man se hur väl värderingsmetoderna fungerar i praktiken. Den här studien visar att bägge värderingsmetoderna systematiskt felskattar de framtida intäktsflödena från bägge resurser.

The dust particles generated due to mechanical wear of iron ore pellets and clusters formed in molten stainless steel alloyed with rare earth metals (REM) are considered in this study. Firstly, the influence of the characteristics of iron ore pellets, applied load on a pellet bed and partial reduction of the pellets on the size distribution of the generated dust was investigated. Secondly, REM clusters are investigated to evaluate the size distribution of the clusters. Also, an extreme value distribution (EVD) analysis has been applied for the observed REM clusters. The large sized pellets showed 10-20% higher wear rate than small sized pellets during wear in a planetary mill. Moreover, an increase of ~67% was observed in the friction and dust generation in the pellet bed as the applied load increased from 1 to 3 kg. Also, it was observed that a higher friction in the pellet bed can lead to an increased amount of airborne particles. The mechanical wear experiments of pellets reduced at 500 °C (P500) and 850 °C (P850) showed that P500 pellets exhibit ~16-35% higher wear rate than unreduced pellets. For the P850 pellets, the wear is inhibited by formation of a metallic layer at the outer surface of the pellets. The mechanism of dust generation has been explained using the obtained results. A reliable cluster size distribution of REM clusters was obtained by improving the observation method and it was used to explicate the formation and growth mechanism of REM clusters. The results show that the growth of clusters is governed by different types of collisions depending on the size of the clusters. For EVD analysis three different size parameters were considered. Moreover, using the maximum length of clusters results in a better correlation of EVD regression lines compared to other size parameters. Moreover, a comparison of predicted and observed maximum lengths of clusters showed that further work is required for the application of EVD analyses for REM clusters. / Studien fokuserar på två olika typer av mikropartiklar som är valda från olika delar av järn- och ståltillverkningsprocessen. Dessa partiklar är dels stoft som genereras på grund av mekanisk nötning av partiklar och dels klusters som bildas i flytande rostfria stål legerade med sällsynta jordartsmetaller (REM). Inledningsvis så undersöktes inverkan av tre faktorer på storleksfördelningen hos stoft som bildas vid hantering av järnoxidpellets. De undersökta faktorerna inkluderade karakteristiken hos järnoxidpellets, det applicerade trycket på pelletsbädden och den partiella reduktionen av järnoxidpellets. Därefter så utfördes tredimensionella undersökningar av REM kluster som extraherats med hjälp av elektrolytisk extraction för att bestämma storleksfördelningen hos klustren. Dessutom så utfördes en extremvärdesdistribution (EVD) studie för de studerade klustren. En planetkvarn användes för att undersöka inverkan of karakeristiken hos pellets på stoftbildningen. Resultaten visade att storleken på pellets kan påverka nötningshastigheten under dessa försöksförhållanden. Pellets som hade en större storlek (13.5&lt; Deq &lt;15.0 mm) uppvisade en 10 till 20% högre nötningshastighet i jämförelse med mindre pellets (9.5&lt; Deq &lt;12.5 mm). Baserat på analyserna av stoftet som genererades under nötningsexperimenten så konstaterades att nötningsmekanismerna för dessa pellets var abrasions- och kollisionsnötning. En pelletsbädd skapades för att möjliggöra studier av inverkan av ett applicerat tryck på stoftbildningen och friktionskrafterna i en pelletsbädd. Ett varierat tryck på mellan 1 till 3 kg applicerades på pelletsbädden. Resultaten visade att en ökning på ~67% av friktionskraften och stoftbildningen ägde rum när det applicerade trycket ökades från 1 till 3kg. Dessutom så visade resultaten att en högre friktionskraft i pelletsbädden kan resultera in en ökad mängd luftburna partiklar. Den mekaniska nötningen av pellets som reducerats vid 500 °C (P500) och 850 °C (P850) studerades också genom användande av en planetkvarn. Resultaten visade att P500 pellets uppvisade en ~ 16 till 35% högre nötningshastighet i jämförelse med oreducerade referenspellets.  Resultaten för P850 pellets visade att den mekaniska nötningen motverkades genom bildningen av ett metalliskt skikt på den yttre delen av pelletsen. Resultaten visade också att stoftet som bildats pga mekanisk nötning av reducerade pellets innehöll 3 till 6 gånger mer grova partiklar  (&gt;20µm) i jämförelse med stoft som bildats från oreducerade pellets. Slutligen så diskuterades hur dessa resultat kan relateras till industriella förhållanden med avseende på mekanismerna som är involverade i den mekaniska nötningen av pellets samt med avseende på relationen mellan hastigheten av de utgående gaserna och storlken och morfologin hos stoftpartiklarna. Klusters innehållande REM-oxider som extraherats från en 253MA rostfri stålsort undersöktes med användande av en tredimensionell teknik. En trovärdig storleksfördelning av klusters (CSD) erhölls genom att förbättra undersökningsmetoden och denna användes för att studera bildningen och tillväxten av REM oxider. Dessutom så användes cirkularitetsfaktorn hos klusters för att dela in klustren i två olika grupper, vilka bildas och tillväxer enligt olika mekanismer. Resultaten visade också att tillväxten av klusters gynnas av olika typer av kollisioner som beror av av storleken på klusters. För REM-klusters så drogs slutsatsen att turbulenta kollisioner är den huvudsakliga mekanismen som påverkar tillväxten. Avhandlingen behandlar även problemet om hur det är möjligt att hantera synfält där det inte förekommer kluster vid en extremvärdesdistribution (EVD) analys. Tre olika parametrar undersöktes i EVD analysen. Resultaten visar att om den maximala längden på kluster (LC) används i analysen så erhålls den bästa korrelationen gällande regressionslinjen för en EVD analys. Specifikt så var R2 värdet upp till 0.9876 i jämförelse med de andra storleksparametrarna som har värden i intervallet 0.9656 – 0.9774. Slutligen så visar resultaten från en jämförelse mellan beräknade och observerade maximala klusterlängder att EVD analyser för studier av REM kluster behöver undersökas ytterligare i framtiden. / <p>QC 20161128</p>