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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
221

Watershed reconstruction during the rehabilitation of surface mined disturbances

Stieg, Elizabeth A January 2011 (has links)
Typescript (photocopy). / Digitized by Kansas State University Libraries
222

Telemetry Recorders and Disruptive Technologies

Kortick, David 10 1900 (has links)
ITC/USA 2009 Conference Proceedings / The Forty-Fifth Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2009 / Riviera Hotel & Convention Center, Las Vegas, Nevada / Telemetry data recorders are not immune to the effects that a number of disruptive technologies have had on the telemetry industry. Data recorder designs today make use of data buses, storage types and graphical user interfaces that are constantly evolving based on the advances of personal computer and consumer electronics technologies. Many of these recorders use embedded designs that integrate disruptive technologies such as PCI Express for realtime data and signal processing, SATA interfaces for data storage and touchscreen technologies to provide an intuitive operator interface. Solid state drives also play a larger role in the latest recorder designs. This paper will explore the effects of these technologies on the latest telemetry recorders in terms of the benefits to the users, cost of implementation, obsolescence management, and integration considerations. The implications of early adoption of disruptive technologies will also be reviewed.
223

Reducing the total cost of ownership of mining haul trucks

Riley, Lennard Barry 12 1900 (has links)
Thesis (MScIngwet)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: The diesel consumption of haul trucks deployed on opencast mines was investigated as a means of reducing the Total Cost of Ownership (TCO) of mining haul trucks. The conceptualisation of TCO and an introduction to the mining operation was presented as an introduction to the field of research. Thereafter, a review of the available literature revealed that linear programming, queueing theory and coast-down testing were applicable means of investigation. The relevant engineering sciences were applied and correlated with experimental and measured data from the Grootegeluk, Sishen and Thabazimbi mines operated by Kumba Resources Ltd (formerly known as ISCOR Mining). A cost-driver model for diesel consumption was formulated by exploiting the expert judgement of role players in the mining operation. A cost-driver model was developed for the Sishen, Thabazimbi and Grootegeluk mines. The cost-driver models were then modelled as a linear programming problem and solved using the student version of LINDO Optimization Software. The results were discussed and a universal diesel cost driver model was formulated by consolidating the individual diesel cost driver models. The operational cycle of haul trucks was simulated in order to quantify equipment utilisation and reduce diesel consumption of the mining vehicles. The operational cycle of haul trucks was modelled utilising queueing theory. The simulation of the queue network was implemented in Matlab using the next event advance method and was called Q Sim. Q Sim - - was utilised to investigate optimal fleet size and the economies of scale of haul truck capacity. The results of coast down tests were analysed in order to determine the effect of treating mining roads, with a bitumen product, on rolling resistance coefficient. Finally, recommendations for further research are proposed. This includes further refinement of the diesel cost-driver model, expanding the scope of application of Q_Sim in the mining operation and further investigation of dust reduction by bitumen products. / AFRIKAANSE OPSOMMING: Ondersoek is ingestel na die dieselverbruik van myntrokke sodoende die Totale Koste van Eienaarskap (TKE) van myntrokke te verminder. Die konsep rondom TKE is bespreek en 'n inleiding tot die mynybedryf is aangebied sodoende die verskeie aspekte in verb and te bring. 'n Literatuur studie het gevolg, wat aangetoon het dat lineere programmeering, toustaan-en loswieltoetse toepaslike navorsingsmetodes is om die nodige resultate te verkry. Daarna is hierdie ingenieurswetenskappe toegepas en 'n vergelyking is tussen die eksperimentele en gemete data van die Grootegeluk, Sishen en Thabazimbi myne getref. 'n Diesel koste-drywer model is opgestel met die insette van kundige rolspelers in die mynbou bedryf. Dit het gelei tot Koste-drywer modelle vir die Sishen, Thabazimbi en Grootegeluk myne. Die modelle is met lineere programmeering as probleemstelling daargestel en is deur middel van die studente weergawe van die LINDO optimaliseringssagteware opgelos. Die resultate was toe bespreek en daarvolgens is 'n universele diesel koste-drywer model opgestel deur die reeds-geskepte modelle te konsolideer. Die operasionele siklus van myntrokke was gesimuleer sodoende die benutting van toerusting te kwantifiseer en die dieselverbruik van myntrokke te verminder. Hierdie operasionele siklus was gemodelleer deur middel van die toustaan-teorie. Die simulasie van 'n toustaannetwerk was in Matlab gevoer deur Q_Sim te gebruik. Hierdie metode was gebruik om die optimale vloot grootte en die invloed van myntrokkapasiteit te ondersoek. Die ontleding van die loswieltoetse was gedoen om die invloed van In bitumen prod uk op rolweerstand te bepaal. Ten slotte is aanbevelings vir toekomstige navorsing bespreek. Dit behels die verder aansuiwerings van die diesel koste-drywer model, die uitbreiding van aanwending van die Q_Sim in die mynbou en 'n verdere ondersoek om stofvoorkoming in die mynbou te bewerkstellig deur die gebruikmaking van bitumen produkte.
224

Modelling of dragline dynamics

Crous, Pieter Gobregts 03 1900 (has links)
Thesis (MEng) -- Stellenbosch University, 2000. / ENGLISH ABSTRACT: The utilisation ofDraglines to remove overburden in surface mining operations is often the process that determines the output of these operations. The bucket and its rigging have been identified as important components where design changes can improve the efficiency of the dragline. It is necessary to create a method to predict the dynamic behaviour of the bucket when various design changes are made to the rigging and the bucket. A rigid multibody dynamic method is formulated that can be used to predict the behaviour of any physical system that can be modelled as a set of connected rigid bodies. This multibody method is verified with analytic test problems and an experiment. A description is given how to use this rigid multibody dynamic method to model the dragline and predict the behaviour ofthe bucket during an operational cycle. / AFRIKAANSE OPSOMMING: Sleepgrawe word gebruik in oppervlakmynbouaktiwiteite om die mineraal neerslae wat ontgin word te ontbloot. Hierdie proses bepaal baie keer die produksie van die mynbou aktiwiteit. Die sleepgraaf se bak en die takelwerk van die bak het 'n groot invloed op die sleepgraaf se werksverrigting. Om die bak se werksverrigting te verbeter is 'n metode nodig om die dinamiese gedrag van die bak te voorspel. In hierdie dokument word 'n metode beskryf waarmee die dinamiese gedrag van enige stelsel bepaal kan word, wat as 'n stelsel van onderling-verbinde onbuigbare liggame beskryf kan word. Die korrektheid van hierdie metode is getoets met behulp van analitiese sowel as eksperimentele metodes. Daar word ook 'n beskrywing gegee hoe hierdie metode gebruik kan word om die beweging van die bak tydens 'n tipiese werksiklus te voorspel.
225

Heuristics for offline rectangular packing problems

Ortmann, Frank 03 1900 (has links)
Thesis (PhD (Logistics))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Packing problems are common in industry and there is a large body of literature on the subject. Two packing problems are considered in this dissertation: the strip packing problem and the bin packing problem. The aim in both problems is to pack a speci ed set of small items, the dimensions of which are all known prior to packing (hence giving rise to an o ine problem), into larger objects, called bins. The strip packing problem requires packing these items into a single bin, one dimension of which is unbounded (the bin is therefore referred to as a strip). In two dimensions the width of the strip is typically speci ed and the aim is to pack all the items into the strip, without overlapping, so that the resulting packing height is a minimum. The bin packing problem, on the other hand, is the problem of packing the items into a speci ed set of bins (all of whose dimensions are bounded) so that the wasted space remaining in the bins (which contain items) is a minimum. The bins may all have the same dimensions (in which case the problem is known as the single bin size bin packing problem), or may have di erent dimensions, in which case the problem is called the multiple bin size bin packing problem (MBSBPP). In two dimensions the wasted space is the sum total of areas of the bins (containing items) not covered by items. Many solution methodologies have been developed for above-mentioned problems, but the scope of the solution methodologies considered in this dissertation is restricted to heuristics. Packing heuristics follow a xed set of rules to pack items in such a manner as to nd good, feasible (but not necessarily optimal) solutions to the strip and bin packing problems within as short a time span as possible. Three types of heuristics are considered in this dissertation: (i) those that pack items into levels (the heights of which are determined by the heights of the tallest items in these levels) in such a manner that all items are packed along the bottom of the level, (ii) those that pack items into levels in such a manner that items may be packed anywhere between the horizontal boundaries that de ne the levels, and (iii) those heuristics that do not restrict the packing of items to levels. These three classes of heuristics are known as level algorithms, pseudolevel algorithms and plane algorithms, respectively. A computational approach is adopted in this dissertation in order to evaluate the performances of 218 new heuristics for the strip packing problem in relation to 34 known heuristics from the literature with respect to a set of 1 170 benchmark problem instances. It is found that the new level-packing heuristics do not yield signi cantly better solutions than the known heuristics, but several of the newly proposed pseudolevel heuristics do yield signi cantly better results than the best of the known pseudolevel heuristics in terms of both packing densities achieved and computation times expended. During the evaluation of the plane algorithms two classes of heuristics were identi ed for packing problems, namely sorting-dependent and sortingindependent algorithms. Two new sorting techniques are proposed for the sorting-independent algorithms and one of them yields the best-performing heuristic overall. A new heuristic approach for the MBSBPP is also proposed, which may be combined with level and pseudolevel algorithms for the strip packing problem in order to nd solutions to the problem very rapidly. The best-performing plane-packing heuristic is modi ed to pack items into the largest bins rst, followed by an attempted repacking of the items in those bins into smaller bins with the aim of further minimising wasted space. It is found that the resulting plane-packing algorithm yields the best results in terms of time and packing density, but that the solution di erences between pseudolevel algorithms are not as marked for the MBSBPP as for the strip packing problem. / AFRIKAANSE OPSOMMING: Inpakkingsprobleme kom algemeen in die industrie voor en daar is 'n aansienlike volume literatuur oor hierdie onderwerp. Twee inpakkingsprobleme word in hierdie proefskrif oorweeg, naamlik die strook-inpakkingsprobleem en die houer-inpakkingsprobleem. In beide probleme is die doel om 'n gespesi seerde versameling klein voorwerpe, waarvan die dimensies almal voordat inpakking plaasvind, bekend is (en die probleem dus 'n sogenaamde a yn-probleem is), in een of meer groter houers te pak. In die strook-inpakkingsprobleem word hierdie voorwerpe in een houer, waarvan een dimensie onbegrens is, ingepak (hierdie houer word dus 'n strook genoem). In twee dimensies word die wydte van die strook gewoonlik gespesi seer en is die doel om al die voorwerpe sonder oorvleueling op s o 'n manier in die strook te pak dat die totale inpakkingshoogte geminineer word. In die houer-inpakkingsprobleem, daarenteen, is die doel om die voorwerpe op s o 'n manier in 'n gespesi seerde aantal houers (waarvan al die dimensies begrens is) te pak dat die vermorste of oorblywende ruimte in die houers (wat wel voorwerpe bevat) 'n minimum is. Die houers mag almal dieselfde dimensies h^e (in welke geval die probleem as die enkelgrootte houer-inpakkingsprobleem bekend staan), of mag verskillende dimensies h^e (in welke geval die probleem as die veelvuldige-grootte houer-inpakkingsprobleem bekend staan, afgekort as VGHIP). In twee dimensies word die vermorste ruimte geneem as die somtotaal van daardie deelareas van die houers (wat wel voorwerpe bevat) waar daar geen voorwerpe geplaas word nie. Verskeie oplossingsmetodologie e is al vir die bogenoemde twee inpakkingsprobleme ontwikkel, maar die bestek van die metodologie e wat in hierdie proefskrif oorweeg word, word beperk tot heuristieke. 'n Inpakkingsheuristiek volg 'n vaste stel re els waarvolgens voorwerpe in houers gepak word om so spoedig moontlik goeie, toelaatbare (maar nie noodwendig optimale) oplossings tot die strook-inpakkingsprobleem en die houer-inpakkingsprobleem te vind. Drie tipes inpakkingsheuristieke word in hierdie proefskrif oorweeg, naamlik (i) heuristieke wat voorwerpe langs die onderste randte van horisontale vlakke in die houers pak (die hoogtes van hierdie vlakke word bepaal deur die hoogtes van die hoogste item in elke vlak), (ii) heuristieke wat voorwerpe op enige plek binne horisontale stroke in die houers pak, en (iii) heuristieke waar inpakking nie volgens horisontale vlakke of stroke beperk word nie. Hierdie drie klasse heuristieke staan onderskeidelik as vlakalgoritmes, pseudo-vlakalgoritmes en platvlakalgoritmes bekend. 'n Berekeningsbenadering word in hierdie proefskrif gevolg deur die werkverrigting van die 218 nuwe heuristieke vir die strook-inpakkingsprobleem met die werkverrigting van 34 bekende heuristieke uit die literatuur te vergelyk, deur al die heuristieke op 1 170 toetsprobleme toe te pas. Daar word bevind dat die nuwe vlakalgoritmes nie 'n noemenswaardige verbetering in oplossingskwaliteit in vergeleke met soortgelyke bestaande algoritmes in die literatuur lewer nie, maar dat verskeie nuwe pseudo-vlakalgoritmes wel noemenswaardige verbeteringe in terme van beide inpakkingsdigthede en oplossingstye in vergeleke met die beste bestaande algoritmes in die literatuur lewer. Assessering van die platvlakalgoritmes het gelei tot die identi kasie van twee deelklasse van algoritmes, naamlik sorteringsafhanklike- en sorteringsonafhanklike algoritmes. Twee nuwe sorteringstegnieke word ook vir die deelklas van sorteringsonafhanklike algoritmes voorgestel, en een van hulle lewer die algeheel beste inpakkingsheursitiek. 'n Nuwe heuristiese benadering word ook vir die VGHIP ontwikkel. Hierdie benadering kan met vlak- of pseudo-vlakalgoritmes vir die strook-inpakkingsprobleem gekombineer word om baie vinnig oplossings vir die VGHIP te vind. Die beste platvlakheuristiek vir die strookinpakkingsprobleem word ook aangepas om voorwerpe eers in die grootste houers te pak, en daarna in kleiner houers te herpak met die doel om vermorste ruimte verder te minimeer. Daar word bevind dat die resulterende platvlakalgoritme die beste resultate in terme van beide inpakkingsdigtheid en oplossingstyd lewer, maar dat oplossingsverskille tussen die pseudovlakalgoritmes nie so opmerklik vir die VGHIP is as wat die geval met die strookinpakkingsprobleem was nie.
226

Slope stability of the Pit Number One, El Encino mine, southern Jalisco, Mexico

Hernandez-Villanueva, Alfredo Ausencio, 1958- January 1987 (has links)
Experimental and analytical investigations were conducted to evaluate the overall stability for the final slope of the Pit Number One at El Encino mine, an iron ore property in Jalisco, Mexico. Shear strength of the intact rock and fractures was estimated from laboratory tests and back-analyses of previous slope failures. Back-analysis estimates were found to be more appropriate to represent the shear strength of fractures. Equal-area stereoplots were used to analyze geological structure data to differentiate structural domains with similar structural characteristics within the final slope. A kinematic analysis was performed for each structural domain using average joint set orientations and major discontinuities projected onto the final slope. The final pit walls were found to be stable, except for a 36,000 ton wedge and a 12,000 ton plane shear slide. These geometries and other potentially unstable areas were analyzed, and control measures and additional work suggested.
227

Track quality monitoring for the compact muon solenoid silicon strip tracker

Goitom, Israel January 2009 (has links)
The CMS Tracker is an all silicon detector and it is the biggest of its kind to be built. The system consists of over 15,000 individual detector modules giving rise to readout through almost 107 channels. The data generated by the Tracker system is close to 650 MB at 40 MHz. This has created a challenge for the CMS collaborators in terms of data storage for analysis. To store only the interesting physics data the readout rate has to be reduced to 100 Hz where the data has to be ltered through a monitoring system for quality checks. The Tracker being the closest part of the detector to the interaction point of the CMS creates yet another challenge that needs the data quality monitoring system. As it operates in a very hostile environment the silicon detectors used to detect the particles will be degraded. It is very important to monitor the changes in the sensor behaviour with time so that to calibrate the sensors to compensate for the erroneous readings. This thesis discusses the development of a monitoring system that will enable the checking of data generated by the tracker to address the issues discussed above. The system has two parts, one dealing with the data used to monitor the Tracker and a second one that deals with statistical methods used to check the quality of the data.
228

Měření drah částic pomocí vnitřního detektoru ATLAS / Měření drah částic pomocí vnitřního detektoru ATLAS

Malina, Lukáš January 2014 (has links)
The SCT is a silicon strip detector forming a part of the tracking system of the ATLAS experiment at the LHC. The tracking performance of SCT is influenced by several fundamental effects: multiple scattering, Lorentz drift, energy loss variation, noise occupancy, and δ-ray production. In this thesis, the task requested by the SCT detector group has been performed. Clusters containing a δ-ray, which are assigned to a track were studied on data samples, specially prepared for this purpose. A correction to the affected cluster positions was successfully developed. The correction to δ-rays has been implemented into the ATHENA reconstruction framework and its performance was evaluated. A meaningful usage of correction for the detector alignment has been proposed. The ongoing detailed verification of the performance within the event reconstruction is partially beyond the scope of the thesis work.
229

Cost-effective strategies for dust control in an opencast coal mine

Amponsah-Dacosta, Francis 03 March 2015 (has links)
Thesis (M.Sc. (Engineering))--University of the Witwatersrand, Faculty of Engineering, 1987.
230

Development of a mining model and a financial analysis for the Entuba Coalfields - Zimbabwe

Botha, Quentin January 2016 (has links)
Master of Science in Engineering by advanced coursework and research: A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering Johannesburg, 2016 / The mining sector plays a significant role in the economy of Zimbabwe. The mining sector is the second largest contributor to the country’s GDP at over 20%. Zimbabwe as a country is endowed with abundant mineral resources. The top three commodities in terms of estimated resources are iron ore, coal and platinum with resources of 30 billion tonnes, 26 billion tonnes and 2.8 billion tonnes respectively. Zimbabwe’s vast mineral resources and reserves are of strategic importance to the Zimbabwe economy. Coal mining is one of the major economic contributors to the mining industry in Zimbabwe. The purpose of the study is to determine the optimal operational model for Makomo Resources from a mining and processing point of view. The study is based on a coal-mining project in the Zimbabwean mining industry. Makomo Resources is the largest privately owned coal mining company in the country, which has a mining licence to perform coal-mining activities in the north-west part of the Bulawayo Mining District of Zimbabwe. Makomo Resources applies a conventional strip mining method by means of truck and shovel to extract the coal reserves. Makomo Resources is supplying over 200,000 tonnes of coal per month to the local and export market. The mine has invested in USD20 million capital to commission a wash plant. The study investigates how to optimise the plant throughput by comparing two mining options: Mining Option 1 - crush and screen 2m power coal, crush & screen and wash a full 7m low ash coal seam and wash 2m of coking coal. Mining Option 2 – crush and screen 2m power coal, crush & screen a 3m low sulphur coal seam and wash low ash coal and coking coal of 4m and 2m respectively. The study investigated all the marketing, geology, mining and financial parameters in the Zimbabwean coal mining context. The study determines the appropriate mining methodology and explore to optimise the coal processing. Two financial models were developed to evaluate and compare the two proposed mining options, determine their feasibility and conclude the optimal mining model. Financial techniques were used to analyse and evaluate the two mining options. The financial models were used to analyse and evaluate the following:  The cashflow over the 10-year period.  The Net Present Value (NPV) and Internal Rate of Return (IRR) of each mining option.  The payback period of the washing plant.  Profitability Index per mining option. The NPV of a project determines the economic value of the mining project. The decision on a mining investment is mostly related to the NPV and IRR of the project. Discounted Cash flow (DCF) models were developed for both mining options that shows project cash in and out flows and calculates economic indicators, such as IRR and NPV. The NPV and IRR were the main methods for the evaluation of the two mining options. The resulting DCF models were developed in an Excel spreadsheet format designed for a 10-year Life of Mine (LOM) period. Mining Option 1 has a higher NPV of USD38.2 million in comparison to USD9.7 million for Mining Option 2. The IRR for Mining Option 1 was calculated at 48%, which is bigger than the IRR for Mining Option 2 of 26%. Mining Option 1 has a simple payback period and discounted payback period of 2.7 years and 4.9 years respectively. Mining Option 2 has a simple payback period and discounted payback period of 3.9 years and 11.9 years respectively. Mining Option 1 has a shorter payback period than Mining Option 2. Both mining options have a Profitability Index (PI bigger than one with Mining Option 1 and Mining Option 2 recording values of 1.87 and 1.18 respectively. Mining Option 1 has the better PI value and is therefore more profitable. Based on the economic evaluation, Mining Options 1 is by far more attractive than Mining Option 2, which results in a better return on the investment and profitability, therefore the preferred option. / MT2017

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