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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.
1

Contribution to the capacity determination of semi-mobile in-pit crushing and conveying systems

Ritter, Robert 04 January 2017 (has links) (PDF)
As ore grades decline, waste rock to ore ratios increase and mines become progressively deeper mining operations face challenges in more complex scenarios. Today´s predominant means of material transport in hard-rock surface mines are conventional mining trucks however despite rationalisation efforts material transportation cost increased significantly over the last decades and currently reach up to 60% of overall mining. Thus, considerations and efforts to reduce overall mining costs, promise highest success when focusing on the development of more economic material transport methods. Semi-mobile in-pit crusher and conveyor (SMIPCC) systems represent a viable, safer and less fossil fuel dependent alternative however its viability is still highly argued as inadequate methods for the long term projection of system capacity leads to high uncertainty and consequently higher risk. Therefore, the objective of this thesis is to develop a structured method for the determination of In-pit crusher and conveyor SMIPCC system that incorporates the random behaviour of system elements and their interaction. The method is based on a structured time usage model specific to SMIPCC system supported by a stochastic simulation. The developed method is used in a case study based on a hypothetical mine environment to analyse the system behaviour with regards to time usage model component, system capacity, and cost as a function of truck quantity and stockpile capacity. Furthermore, a comparison between a conventional truck & shovel system and SMIPCC system is provided. Results show that the capacity of a SMIPCC system reaches an optimum in terms of cost per tonne, which is 24% (22 cents per tonne) lower than a truck and shovel system. In addition, the developed method is found to be effective in providing a significantly higher level of information, which can be used in the mining industry to accurately project the economic viability of implementing a SMIPCC system.
2

Contribution to the capacity determination of semi-mobile in-pit crushing and conveying systems

Ritter, Robert 01 November 2016 (has links)
As ore grades decline, waste rock to ore ratios increase and mines become progressively deeper mining operations face challenges in more complex scenarios. Today´s predominant means of material transport in hard-rock surface mines are conventional mining trucks however despite rationalisation efforts material transportation cost increased significantly over the last decades and currently reach up to 60% of overall mining. Thus, considerations and efforts to reduce overall mining costs, promise highest success when focusing on the development of more economic material transport methods. Semi-mobile in-pit crusher and conveyor (SMIPCC) systems represent a viable, safer and less fossil fuel dependent alternative however its viability is still highly argued as inadequate methods for the long term projection of system capacity leads to high uncertainty and consequently higher risk. Therefore, the objective of this thesis is to develop a structured method for the determination of In-pit crusher and conveyor SMIPCC system that incorporates the random behaviour of system elements and their interaction. The method is based on a structured time usage model specific to SMIPCC system supported by a stochastic simulation. The developed method is used in a case study based on a hypothetical mine environment to analyse the system behaviour with regards to time usage model component, system capacity, and cost as a function of truck quantity and stockpile capacity. Furthermore, a comparison between a conventional truck & shovel system and SMIPCC system is provided. Results show that the capacity of a SMIPCC system reaches an optimum in terms of cost per tonne, which is 24% (22 cents per tonne) lower than a truck and shovel system. In addition, the developed method is found to be effective in providing a significantly higher level of information, which can be used in the mining industry to accurately project the economic viability of implementing a SMIPCC system.
3

Transportation system selection in open-pit mines (Truck-Shovel and IPCC systems) based on the technical, economic, environmental, safety, and social (TEcESaS) indexes

Abbaspour, Hossein 12 January 2021 (has links)
The production of raw materials through mining projects is nowadays very challenging, mainly due to the rapid progress in the industrial and technological fields. On the one hand, they have to fulfill industries' requirements in their demand for materials while making a profit based on the current technologies. On the other hand, they should consider all other limitations, primarily environmental and social challenges that are confronting. The transportation system in any mining project is one of the most significant parts, especially in the technical and economic issues. It must transfer the planned volume of ore/waste that the whole stream of the mining process would not be interrupted and, it can cover the technical challenges and the costs imposed on the project. Additionally, it should be designed and selected to have the lowest environmental impact and the highest safety during the operation. Accordingly, a transportation system selection process that considers all these factors is one of the challenging issues in any mining project. Although the Truck-Shovel system is known as the conventional transportation in open-pit mines, which is preferable because of the low capital cost and high flexibility, it still imposes a high rate of operating costs, safety issues as well as environmental footprints. In-Pit Crushing and Conveying (IPCC) systems are the alternative transportation systems for the Truck-Shovel systems, in which the material is crushed inside the mine’s pit limit and transferred into the outside through conveyor belts. Although these systems are not new, they are mostly neglected as a transportation option basically due to the high capital cost and low flexibility. On the contrary, they can offer more environmentally friendly and safer working areas and a lower operating cost. According to these facts, each transportation system is preferable in a couple of technical, economic, environmental, safety, and social issues. Accordingly, in each circumstance, one or more of these systems can be used in the mining project. However, there is not yet a way or tool that investigates the transportation system selection along with the mine life that takes into account all of these factors. To fill this gap, this project aims to define a model to introduce all these elements while it is interactively connected throughout the mine life. For this and as the first step, the system dynamics modeling is defined and used to build the model for all the technical, economic, environmental, safety, and social factors. As an output of this step, software entitled “TEcESaS Indexes” is designed and produced through Venapp that makes working with the model comfortable. As the second step, a selection method based on the Analytical Hierarchy Process (AHP) is performed that the transportation system selection regarding all the mentioned factors can be made. As the output in this step, the “Sustainability Index” software programmed in the Java language is developed. Considering a hypothetical copper open-pit mine as the case study and implementing the designed software, the results show although the Truck-Shovel system should be used in the first two years of the project (2016 and 2017) in the single expert and deterministic mode, the Fully Mobile In-Pit Crushing and Conveying (FMIPCC) system shows the highest sustainability index among other transportation systems from 2018 until the end of the mine life. While in the group decision making and deterministic simulation, the Truck-Shovel system should be utilized from 2016 to 2020. Additionally, in the group decision making and stochastic mode, the FMIPCC is the selected transportation system with the highest sustainability index probability.
4

Untersuchungen der akustischen Wirkung von Tragrollen zur zielgerichteten Lärmminderung an Gurtförderanlagen / Investigations of the acoustical effect of idlers for a purposeful noise reduction on belt conveyor systems

Täschner, Dirk 17 July 2017 (has links) (PDF)
Gurtförderanlagen werden im Bergbau und anderen Industriezweigen zum Transport von Schüttgütern eingesetzt. Der Anlagenbetrieb ist mit Geräuschemissionen verbunden. Dies kann bei Kontrolle und Wartung eine erhöhte Lärmbelastung für betroffene Mitarbeiter hervorrufen. Im Umfeld von Wohnbebauungen oder schutzbedürftigen Objekten kann die Überschreitung von Immissionsrichtwerten zu einer zeitlichen Betriebseinschränkung der hocheffizienten Anlagen führen. Zur Lärmminderung an der Quelle oder deren Nähe erfordert dies technische Schallschutzmaßnahmen. Die Tragrollen im Obertrum der Gurtförderanlagen sind bei der akustischen Wirkung von entscheidender Bedeutung. Mit einem Prüfstand für Tragrollen ist deren Schallleistung bei unterschiedlichen Geschwindigkeiten bestimmbar. Die Ergebnisse lassen Rückschlüsse auf die mechanische Belastung und die Schallemission beim Betrieb in einer Förderanlage zu. Die Arbeit benennt die Ursachen der Geräuschemissionen beim Ablauf der Rollen und stellt diese in Verbindung mit den Eigenschaften der Oberfläche und der Außermittigkeit der Drehachse dar. Die Prüfung beider Parameter basiert auf einer Rundlaufmessung. Die gewonnenen winkelabhängigen Daten erlauben eine Berechnung der Exzentrizität der Drehachse und des Verlaufs der Kreisformabweichung auf dem Rollenmantel. Daraus abgeleitete Kennwerte dienen als Vorgaben zur Anpassung und Entwicklung von Herstellungsverfahren sowie zur gezielten Auswahl geräuscharmer Tragrollen für Gurtförderanlagen. / Belt conveyor systems are used in mining operations and other industry sectors to transport bulk material. The plant operation is being linked to noise emissions. During inspections and maintenance this can cause an increased noise exposure for affected employees. In the environment of residential buildings or areas in need of protection the exceedance of immission guideline values can lead to a temporary operational limitation of these highly efficient plants. Noise abatement measures primarily at the source or in the vicinity are required to reduce noise immission. The idlers on the carrying belt side of the belt conveyor systems are of crucial importance to the acoustical properties. Their sound power level is determinable at different belt speeds with a test stand for idlers. The results allow conclusions about the mechanical stress and sound emissions during operation in a belt conveyor system. The thesis identifies the sources of noise during the roll process and places them in conjunction with the properties of the surface and the centre offset of the axis. The examination of these two parameters is based on a total indicator reading (TIR) measurement. The angle-dependent data obtained allow a calculation of the eccentricity of the axis and the curve of the circular deviation of the roller tubes. Therefrom derived characteristic values serve as specifications for the adaptation and development of manufacturing processes as well as for a careful selection of low noise idlers for belt conveyors.
5

Untersuchungen der akustischen Wirkung von Tragrollen zur zielgerichteten Lärmminderung an Gurtförderanlagen

Täschner, Dirk 19 December 2013 (has links)
Gurtförderanlagen werden im Bergbau und anderen Industriezweigen zum Transport von Schüttgütern eingesetzt. Der Anlagenbetrieb ist mit Geräuschemissionen verbunden. Dies kann bei Kontrolle und Wartung eine erhöhte Lärmbelastung für betroffene Mitarbeiter hervorrufen. Im Umfeld von Wohnbebauungen oder schutzbedürftigen Objekten kann die Überschreitung von Immissionsrichtwerten zu einer zeitlichen Betriebseinschränkung der hocheffizienten Anlagen führen. Zur Lärmminderung an der Quelle oder deren Nähe erfordert dies technische Schallschutzmaßnahmen. Die Tragrollen im Obertrum der Gurtförderanlagen sind bei der akustischen Wirkung von entscheidender Bedeutung. Mit einem Prüfstand für Tragrollen ist deren Schallleistung bei unterschiedlichen Geschwindigkeiten bestimmbar. Die Ergebnisse lassen Rückschlüsse auf die mechanische Belastung und die Schallemission beim Betrieb in einer Förderanlage zu. Die Arbeit benennt die Ursachen der Geräuschemissionen beim Ablauf der Rollen und stellt diese in Verbindung mit den Eigenschaften der Oberfläche und der Außermittigkeit der Drehachse dar. Die Prüfung beider Parameter basiert auf einer Rundlaufmessung. Die gewonnenen winkelabhängigen Daten erlauben eine Berechnung der Exzentrizität der Drehachse und des Verlaufs der Kreisformabweichung auf dem Rollenmantel. Daraus abgeleitete Kennwerte dienen als Vorgaben zur Anpassung und Entwicklung von Herstellungsverfahren sowie zur gezielten Auswahl geräuscharmer Tragrollen für Gurtförderanlagen.:1 Veranlassung und Bedeutung des Themas 2 Stand der Technik und des Wissens 3 Weiterentwicklung von Methoden zur Erfassung der Geräuschemission an Gurtförderanlagen 4 Entwicklung und Aufbau eines Prüfstandes zur Beschreibung der akustischen Eigenschaften von Tragrollen 5 Mathematische Modellierung zur Aufnahme geometrischer Rundlaufeigenschaften von Tragrollen 6 Technikums- und Feldversuche zur Validierung des mathematischen Modells und der akustischen Wirkung 7 Schlussfolgerungen zur Geräuschminderung an Förderanlagen / Belt conveyor systems are used in mining operations and other industry sectors to transport bulk material. The plant operation is being linked to noise emissions. During inspections and maintenance this can cause an increased noise exposure for affected employees. In the environment of residential buildings or areas in need of protection the exceedance of immission guideline values can lead to a temporary operational limitation of these highly efficient plants. Noise abatement measures primarily at the source or in the vicinity are required to reduce noise immission. The idlers on the carrying belt side of the belt conveyor systems are of crucial importance to the acoustical properties. Their sound power level is determinable at different belt speeds with a test stand for idlers. The results allow conclusions about the mechanical stress and sound emissions during operation in a belt conveyor system. The thesis identifies the sources of noise during the roll process and places them in conjunction with the properties of the surface and the centre offset of the axis. The examination of these two parameters is based on a total indicator reading (TIR) measurement. The angle-dependent data obtained allow a calculation of the eccentricity of the axis and the curve of the circular deviation of the roller tubes. Therefrom derived characteristic values serve as specifications for the adaptation and development of manufacturing processes as well as for a careful selection of low noise idlers for belt conveyors.:1 Veranlassung und Bedeutung des Themas 2 Stand der Technik und des Wissens 3 Weiterentwicklung von Methoden zur Erfassung der Geräuschemission an Gurtförderanlagen 4 Entwicklung und Aufbau eines Prüfstandes zur Beschreibung der akustischen Eigenschaften von Tragrollen 5 Mathematische Modellierung zur Aufnahme geometrischer Rundlaufeigenschaften von Tragrollen 6 Technikums- und Feldversuche zur Validierung des mathematischen Modells und der akustischen Wirkung 7 Schlussfolgerungen zur Geräuschminderung an Förderanlagen

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