Thesis (Ph. D.)--Industrial and Systems Engineering, Georgia Institute of Technology, 2007. / Yorai Wardi, Committee Member ; Gunter Sharp, Committee Member ; Spiridon Reveliotis, Committee Member ; Leon F. McGinnis, Committee Member ; Chen Zhou, Committee Chair.

M.Com. (Business Management) / Background Best cost country sourcing is a relatively new concept and not many organisations are utilising this specific process nor are they optimising this as their sourcing strategy. Best cost country sourcing is one of the most profound sourcing processes available, and it has the ability to increase an organisation’s efficiency and effectiveness if implemented correctly. Purpose The purpose of this study is to determine if best cost country sourcing should be used as an alternative to local sourcing. It includes aspects of the best cost country sourcing process as well as its risks and advantages. Research method The dissertation analyses the process of best cost country sourcing and the effect it has on an organisation’s sourcing strategy. To achieve this understanding it is necessary to do a qualitative investigation, which is the reason a qualitative research was used as the research methodology in this dissertation. Conclusion Pursuing the process of best cost country sourcing requires a lot of dedication and implementation time. It is a complicated process and no two situations will be alike. Each organisation would need to determine the advantages, risks and challenges which they will encounter with best cost country sourcing. Organisations would also need to determine the best cost countries, as well as the criteria they would need to use in selecting potential suppliers.

An advanced coursework and a project submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements of MSc. Engineering (Mining), November 2015 / General For mining operations, both underground and open cast, there are generally accepted criteria used to arrive at the optimum mining method with which to exploit the ore body economically. Having selected the optimum mining method, mining companies should then make the decision to also select the optimum technology to apply given the various options that are now available. In the case of a shallow massive ore body where open-pit mining has been selected as the optimum mining method, the use of conventional trucks and shovels has been the popular choice but over the years, as pit become deeper, and stripping ratios increase, growing interest and adoption of in-pit crushing and conveying for both ore and waste has been gaining ground with several mining sites currently now operating, testing the systems or conducting studies at various stages for In-pit Crushing and Conveying (IPCC) in its different configurations (Chadwick, 2010). Open pit mining general involves the movement of pre-blasted or loose waste ahead of underlying ore out of the pit or to a previously mined part of the pit. This is then followed by the drilling and blasting or loosening of the ore and transportation to the processing plant or stockpiles. The conventional Truck and Shovel open pit operation involves the use of shovels – electric rope shovels, diesel or electric hydraulic shovels or excavators or front-end loaders to load the blasted, or loose waste and ore material in the pit onto mining trucks which haul the material to crushers or stockpiles if it is ore or to waste dumps in the case of waste. In a Fully Mobile IPCC (FMIPCC) system, the broken or loose material in the pit is loaded into a crusher or sizer by a shovel, continuous miner or dozer, crushed to a manageable size and transported by conveyor belts to the waste dump where it is deposited in place using spreaders if it is waste or onto stockpiles if it is ore. A combination of the two systems is where trucks dump material loaded at the face into a semi mobile crusher or sizer located in the pit close to the loading points N BANDA 392438 before conveying to destination thereby reducing truck haulage distance. In the semi-mobile configuration, the crusher is relocated closer to the loading points to minimise the hauling distance. Other various configurations are also employed depending on the various considerations. Although the Truck and Shovel system is considered as the convention in open pit mining, the IPCC system is not a new concept and has been operational on a number of mines worldwide for quite a number of years (Szalanski, 2010). Loading and hauling receive great attention especially in a high volume open pit mines due to the high cost contribution to the overall operation and therefore, if optimised, good cost savings can be realised (Lamb, 2010). Figure 1: Sishen Mining Cost Breakdown In the case of Sishen Loading and Hauling costs constituted 67% of the mining costs including labour mining support services in 2013 (Kumba Iron Ore, 2013). This picture remains unchanged to a large extent. In some cases the hauling cost alone can make up as much as 60% of the mining operating cost (Meredith May, 2012) Selection of a materials handling system between Truck and Shovel (T/S) and In-pit Crushing and Conveying (IPCC) has proven to be difficult due to limited understanding of the IPCC system especially its advantages and disadvantages relative to the Truck and Shovel system. The aim of this research was to unpack these two systems in terms of their applicability using studies conducted at Sishen 6,5% 8,8% 29,1% 22,7% 9,7% 0,6% 1,3% 0,4% 7,0% 4,2% 3,7% 5,9% Sishen Mining Cost 2013 Blasting Drilling Hauling L&H Contractors Loading Maintenance Other Mining Manangement Mining Engineering Mining Other Resource Management SHEQ Mining Support N BANDA 392438 Mine as well as develop some scorecard that could be used to select one over the other one. Sishen Case Study Sishen Mine is an iron ore open pit mine located in the Northern Cape province of South Africa and is part of Kumba Iron Ore Company which is Anglo American PLC. The mine has been in operation since 1953 with the current life of mine going up to 2030. It produces 44Mt tonnes of product from a 56Mt mine ore at a life of mine strip ratio of 4. One of the planned expansion the north part of the mine known as the GR80 and GR50 areas. Mining in these areas will require pre-stripping of 290Mt of clay material over the life of mine to expose the ore in pre volume phases. Figure2: Sishen Pit –Sishen Mine 2014. Sishen mine is constantly evaluating various technologies in its mining operations aimed at improving its bottom line by way of increasing productivity and efficiency, reducing costs and improving safety, however, the last time that the mine considered evaluating a technology that significantly could have resulted in a totally different operational philosophy was i contracted to institute a study to evaluate technology options for mining and moving majority owned by a minimum of 437Mt of calcrete and the underlying pre- g in 2007 when Snowden Mining Consultants run-ofmine areas is in -planned time and were N BANDA 392438 55 Mt of the calcrete/clay material per year from the waste pushback area in the GR80/GR50 area of the mine from 2009 till 2030. Snowden completed the Prefeasibility study in early 2008 in which they evaluated a conventional Truck and Shovel operation as well as IPCC. Economic viability of both systems in various configurations was demonstrated with the use of larger trucks and shovels ranked as the most economic option in terms of Net Present Cost (NPC), unit owning and operating cost per mined tonne and, to a less extent, in terms of risk and other considerations. In this case, the Truck and Shovel option was more economic than both IPCC configurations. However the small difference in the cost figures gave rise to interest in further evaluations. Following the Snowden study, Sishen engaged Sandvik Mining and Construction in 2008, to review the work done by Snowden and provide more detail and practical input to the IPCC system at scoping level. In the review, the IPCC system was shown to be the economic approach for the waste removal from the target area in terms of owning and operating cost. Practicality was also demonstrated and the case for the consideration of the IPCC system was put forward to Sishen. A further consultant, Sinclair Knight Merz (SKM) of Australia, was engaged, in the later part of 2008, to further evaluate and optimise the IPCC option to further demonstrate practically in detail at a feasible study level and strengthen its case by mitigating perceived risk. This included equipment specifications, mine and equipment layout per period per bench and risk assessment on the IPCC options. The mine, however, implemented the conventional truck and shovel option using larger equipment. The final decision was to stick with the current set up of Truck and Shovel system and gradually replace the current fleet of 730E Komatsu (190 tonne payload) trucks with the 930E or equivalent ( 320 tonne payload) and the current XPB 2300 P& H electric rope shovels and CAT 994/Komatsu WA1200 front end loaders with XPC 4100 P&H electric rope shovels, Komatsu PC8000/Liebherr 996 diesel hydraulic shovels and LeTournea L-2350 front end loaders to reduce the number of equipment and manage the operational cost. This decision was based on issues around initial capital investment, flexibility of the system to suit changing mining plans, ability of current personnel to run the system and general low risk appetite for change. The adopted option has its own challenges N BANDA 392438 such as supporting infrastructure requirements, labour intensity and associated low productivity and high cost, fleet management challenges to achieve required productivity constantly, supplies such as fuel and tyres and safety issues due to traffic density. A high level recalculation of the costs using current information was done as part of this research. For simplicity, no escalations or discounting were applied on future expenditure. The estimated unit owning and operating costs in 2014 terms for the study area were as follows:- Fully Mobile IPCC (FMIPCC) option ZAR 10.38/t, Semi Mobile IPCC (SMIPCC) option ZAR 13.12/t, Truck and Shovel option ZAR 15.80/t. The objective of this research is to use lessons from the Sishen case as well as other operations and gather expert views with the aim of establishing criteria that could be applied in a preliminary evaluation that would determine the suitability of either of the materials handling options. General Approach The costs were recalculated using as much current information as possible. Other considerations including advantages and disadvantages of either of the systems were examined in more detail, with real life examples examined where possible. This resulted in the establishment of generalized criteria for the selection of mining and transport technology for a large open pit mine with focus on conventional Truck and Shovel systems on one hand and IPCC systems, in their various formats, on the other. These criteria which identify conditions necessary for the successful adoption and implementation of either of the systems could then be used as input into the decision to carry out any further detailed studies of the options. The previous study reports on the Sishen mine case were examined, input parameters to the calculations checked and the general approached analyzed for practicality. The relative costs were also viewed for comparative purposes. Literature on these two main systems was reviewed including that from conferences. Other large operations running either one or both systems were looked at to gain N BANDA 392438 further insight. Original Equipment suppliers’ views on these systems were also looked at through many articles in the public domain. Sishen mine has previously had the IPCC system running in the same part of the mine in a semi mobile configuration, crushing and conveying waste. It was then changed to become a supplementary system for the ore handling system and the in pit crusher has never been relocated. The Truck and Shovel system took over the movement of all the waste and most of the ore at the mine. Lessons from these experiences were incorporated in this study.

A simulation model is developed in SLAM II to study and analyze conveyor systems.. The adequacy of the model is tested by applying it to a conveyor layout as well as some variant designs. 1he problem of modeling large systems is reduced by decomposing the system into smaller segments (subsystems). Different types of conveyors are considered. Programming modules are prepared for feasible conveyor types and segments. These simulation modules are integrated into a system. / Master of Science

An experimental program has been undertaken to gain a more fundamental understanding of dense-phase pneumatic transport of cohesionless solids. A 50.8 mm internal diameter circulating unit with both horizontal and vertical sections has been constructed . The pipe material is transparent lexan which allows for visual observation of the flow pattern. The particles used were a mixture of 95% white and 5% black polyethylene granules (particle diameter approximately 3 mm). The black particles were used to aid the visual observation of the flow pattern. The flow patterns ranged from dilute-phase flow to dense-phase plug flow. High-speed photographic techniques have been used to document the flow patterns in both the horizontal and vertical sections. Pressure drop measurements across a 70 cm test section have been coordinated with the film work. At the higher superficial air velocities (approximately 15 m/sec), the particles flow in a dilute suspension within the air stream. The pressure drop across the 70 cm section fluctuates very rapidly. For the horizontal dilute-phase flow, the mean pressure drop is approximately 0.12 kPa with fluctuations ranging from 0 to 0.3 kPa. For the vertical dilute-phase flow, the mean pressure drop is approximately 0.25 kPa with fluctuations ranging from 0 to 0.5 kPa. Upon reducing the superficial air velocity to 6.8 m/sec, the flow pattern in the horizontal section changes to a type of strand flow. The particles are conveyed in a dilute phase above a stationary layer. Large peaks in the pressure drop data (approximately 1 to 2 kPa) correspond to increases in the dilute-phase solids concentration. At the lower superficial air velocities (below 5 m/sec) , the solids flow pattern changes to dense-phase flow. The particles move in the form of plugs that occupy the entire pipe cross-section. For the horizontal flow, the plug length ranged from 0.17 to 0.60 m and the pressure drop across the plugs ranged from 1 to 5.2 kPa. The pressure gradient range can be predicted from the equations of Konrad et al. (1980). The analysis of the vertical dense-phase flow films is not as straightforward as the horizontal films. However, the flow pattern resembles that described by Konrad (1987) and there is qualitative agreement with the concepts outlined by Konrad (1987). / Master of Science

Yes / Extrusion-a unit operation in polymer processing has been in extensive use since the great age of plastic technology. It is a simple operation that enables within one equipment the sequential conveying of solid polymer chips or powder, their melting, mixing, pumping and shaping via a die into a variety of high tonnage and/or value products. Pipes, bottles, films are the most common examples but the list of applications is endless from tiny micromoulded parts to large structural profiles. Extrusion is not limited to plastics but is used hot or cold to process soft solids like food, industrial and pharmaceutical pastes, as well as metals and ceramics. Most of the advances in extrusion processing have concentrated in improving the essential functions of extrusion: solid conveying, melting, pumping and mixing. The literature abounds with descriptions of such advances pushing the limits of the extrusion in an incremental way. In this paper, we describe step-changes in enhancing extrusion, which opens up new applications to better old technology-make them safer, cheaper and cleaner. The new designs presented in this paper have also the potential to develop new reactor technology for viscous fluids.

A formulation was developed for the rheological characterization of highly concentrated suspensions, accounting for the physical effects of particle size distribution. A number of dimensionless parameters were developed signifying the physical characteristics of the solids and the vehicle fluid, and functionally related to the yield-stress and a flow parameter. Each of these expressions of the formulation contains an empirical dimensionless coefficient accounting for the interparticle and fluid/solid interactions that are not explained by the physical parameters involved. A formulation and a methodology were also developed for predicting the shear viscosity behavior of highly concentrated suspensions at low and high shear-rates through the use of three parameters signifying effects of particle size distribution. A number of applications were made using various non-coal and limited coal-liquid mixture data reported in the literature to demonstrate the general validity of the formulations. A methodology was proposed for the analysis of the particle size distribution effects on the overall optimum energy efficiency during hydraulic transportation and particle size reduction. The computer model developed for this purpose was employed to evaluate the transportation energy consumption and the energy consumed in the grinding process to prepare the slurry, in pipes of various sizes and lengths for a coal slurry of various specified particle size distributions and concentrations. Correlations obtained indicated the sensitivity of transportation energy efficiency to various parameters including the maximum packing concentration, relative concentration, specific surface area of particles, surface area mean size, pipe size and length, and annual mixture throughput. The results of combined energy calculations have shown that the particle size distribution and related physical parameters can significantly affect the energy efficiency due to both grinding and transportation, and the delivered cost of slurry fuels. / Ph. D.

Dieser Beitrag ist der Vibrationsfördertechnik zuzuordnen und befasst sich speziell mit dem Prinzip der Gleitförderung bei nichtharmonischer Beschleunigung in horizontaler Ebene. Es werden Zusammenhänge zwischen der Bewegung des Förderorgans und der Berechnung der resultierenden Fördergeschwindigkeit vorgestellt. Anhand der maximalen Fördergeschwindigkeit und der Effizienz einer Bewegungsform werden schließlich optimale Bewegungsgesetze abgeleitet. / This work is assigned to vibratory conveyor engineering and is dealing with the operation principle of sliding conveying by non-harmonical accelaration along horizontal plane surfaces. The relations between motion of the conveyor organ and calculation of the resulting conveying velocity are explained in this paper. Finally, optimal motion laws regarding a high efficiency of the motion patterns are derived from the maximum conveying velocity.

Der vorliegende Beitrag befasst sich mit dem Verhalten von Vibrationsförderern. Speziell für Förderer, welche nach dem Gleitprinzip arbeiten, werden Zusammenhänge zwischen der Antriebslage, dem Fördergut sowie der Ausrichtung des Förderorgans beschrieben. Durch Anwendung der vorgestellten Prinzipien wird eine Berechnungsmethode für die Fördergeschwindigkeit abgeleitet und anschließend mit Versuchswerten verglichen. / This paper deals with the behavior of vibrating conveyors. Especially for conveyors, using a sliding principle of movement, relations between the drive position, the conveyed goods and the orientation of the means of transport are described. By applying the principles presented, a method for calculating the conveying velocity is derived and compared with experimental values.

Dieser Beitrag ist der Vibrationsfördertechnik zuzuordnen und befasst sich speziell mit dem Prinzip der Gleitförderung bei nichtharmonischer Beschleunigung in horizontaler Ebene. Es werden Zusammenhänge zwischen der Bewegung des Förderorgans und der Berechnung der resultierenden Fördergeschwindigkeit vorgestellt. Anhand der maximalen Fördergeschwindigkeit und der Effizienz einer Bewegungsform werden schließlich optimale Bewegungsgesetze abgeleitet. / This work is assigned to vibratory conveyor engineering and is dealing with the operation principle of sliding conveying by non-harmonical accelaration along horizontal plane surfaces. The relations between motion of the conveyor organ and calculation of the resulting conveying velocity are explained in this paper. Finally, optimal motion laws regarding a high efficiency of the motion patterns are derived from the maximum conveying velocity.