The main purpose of this study was to optimise the grain size distribution of the raw material mixture for the production of iron sinter. It well known that the constitution of the sinter mix is based on the knowledge of chemical composition and grain size distribution. Although Mittal Vanderbijlpark has fixed specifications on the physical and chemical properties of the sinter for optimal blast furnace performance, the particle size distribution of the sinter mix has not yet been optimized. This was achieved by using the granulation characteristics of the sinter mix and the green bed permeability tests. The influence of the moisture content of the feed, granulation time, and mean granule diameter on permeability was investigated on Thabazimbi and Sishen iron ore, as well as on their mixture with fluxes and without fluxes. The iron ore results indicated that the mixture containing 20% Thabazimbi iron ore and 80% Sishen iron ore with fluxes where the coke, lime and return fines were sized by removing the – 0.5 mm size fraction of the return fines and coke, and the 1 mm size fraction of lime has the highest permeability of all the studied mixtures. The sintering properties of the mixtures of optimised grain size distributions were also investigated and the results were very similar for all the mixtures and better than the base case mixture, which was not optimised with respect to grain size distribution. / Dissertation (MEng)--University of Pretoria, 2008. / Materials Science and Metallurgical Engineering / unrestricted

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.