ETD Collection

Permanent URI for this collectionhttps://wiredspace.wits.ac.za/handle/10539/104


Please note: Digitised content is made available at the best possible quality range, taking into consideration file size and the condition of the original item. These restrictions may sometimes affect the quality of the final published item. For queries regarding content of ETD collection please contact IR specialists by email : IR specialists or Tel : 011 717 4652 / 1954

Follow the link below for important information about Electronic Theses and Dissertations (ETD)

Library Guide about ETD

Browse

Has files: YesSubject: search.filters.subject.Iron ores--South Africa

Search Results

Now showing 1 - 4 of 4
  • No Thumbnail Available
    Item
    A spatial mine-to-plan compliance framework for open-pit iron ore mines
    (2019) Otto, Theunis Johannes
    A major assumption underpinning this PhD thesis work is that the actual financial returns realised by open-pit mines are not only dependent on agreed upon mine plans but, are also dependent on the level of spatial execution of the mine plans. To ensure the sustainable success of a large open-pit mine two major areas need to be effectively managed namely the quality and integrity of the mine planning process and the spatial execution of the “best” mine plan. Existing literature describes improvements in the mine planning process and the development of more robust and optimised mine plans. Despite improvements in the quality and integrity of mine plans, open-pit iron ore mines often struggle to achieve the targets set in these mine plans, especially from a spatial point of view. Existing literature recognises the value of spatial compliance to a mine plan, but the processes and systems associated with spatial mine-to-plan compliance reconciliation are not adequately addressed. References to practical and integrated approaches for measuring and managing spatial compliance against the approved mine plans are very limited. Where compliance to the mine plan is mentioned, the research has mainly focussed on temporal compliance metrics and have not proposed a comprehensive framework focused on spatial mine-to-plan compliance for open-pit iron ore mines. This thesis took steps towards filling the identified knowledge gaps in existing literature. The purpose of the thesis was to answer the research question on whether spatial compliance can be improved. This was done through the development, implementation and validation of a spatial mine-to-plan compliance framework for open-pit iron ore mines. The framework defines the components and relationships between the components that determine the level of spatial compliance against the tactical mine plan. This allows measurement and ensure effective management of spatial mine-to-plan execution at open-pit iron ore mines. The research methodology followed during the execution of this research thesis was to review existing literature with the aim of establishing the extent and depth of current published information. The thesis then conceptualised and developed a spatial mine-to-plan compliance framework. The approach for the measurement and reconciliation of the spatial mine-to-plan compliance at open-pit iron ore mines was defined. This was followed by the development and application of spatial mine-to-plan compliance driver trees (CDTs). Methodologies were defined for determining, quantifying and interpreting the impact of spatial mine-to-plan compliance performance on the achievement of operational targets and mining flexibility. The research developed the concept of the next best action (NBA) leading to effective decision making. Technology solutions were evaluated and applied to enhance the effectiveness of the framework. Finally, the research was validated through the implementation of the framework at the Kolomela open-pit iron ore mine in South Africa. The Kolomela spatial mine-to-plan index improved from 74% in 2013 to 99% in 2017, confirming that the adoption of the framework led to a significant improvement in the spatial mine-to-plan compliance to the business plan (BP). Insights gained through the application of the CDT contributed to the improvements. Areas that were planned, but not mined at the time of the assessment were targeted through the NBA methodology and the root causes of adverse spatial mine-to-plan reconciliation performance were addressed. Remotely piloted aircraft systems (RPAS) and high precision global positioning systems (HP-GPS) technologies were implemented, thereby enhancing the effectiveness of the spatial mine-to-plan compliance reconciliation process at Kolomela. This was achieved by utilising the technologies to assist with the visualisation of the actual areas mined in relation to the areas planned for mining. The results obtained during the validation illustrated the positive relationship between achieving targeted spatial mine-to-plan reconciliation results and the achievement of budgeted total exposed ore (EO) levels. This confirmed the critical role that spatial mine-to-plan compliance performance plays to ensure the sustainability of the mining operation in the longer-term through maintaining the planned level of mining flexibility. This is achieved by generating the budgeted EO levels which are a proxy for mining flexibility. This thesis contributes to knowledge as a reference based on empirical research validated at Kolomela. The research represents applied knowledge with a significant value contribution that has potential to fundamentally improve open-pit iron ore mining reconciliation practices. The thesis contributes to knowledge in three key areas. Firstly, it developed an integrated spatial mine-to-plan compliance framework for application at open-pit iron ore mines. The framework defined various metrics including a spatial mine-to-plan index. Secondly, it developed and applied spatial mine-to-plan CDTs that provide the ability to drill-down into selected spatial areas within the larger iron ore mine and enable understanding of the root causes of deviations. Lastly, it employed technology solutions (RPAS and HP-GPS) in a novel way to enhance the effectiveness of the spatial mine-to-plan compliance framework.
  • No Thumbnail Available
    Item
    The importance of state-funded data gathering in the generation of exploration targets
    (2018) Saindi, Troth Ntila
    This research report discusses the importance of state-funded geoscientific data sets (also known as pre-competitive data) in the initial generation of mineral exploration targets. These are data sets that any country may and need to have in their geoscientific database to provide either freely or at a minimal fee to the public or prospective investors. Such data sets may include geochemical data, geophysical data, geological data, maps, technical reports, imagery and are usually made available through the state’s Geological Survey Organisations (GSO’s) or any state – run geoscientific institutions like the Council of Geosciences (CGS) in the Republic of South Africa. The availability or unavailability of such data sets during the initial stages of a particular mineral exploration project for a particular exploration destination has a very important effect in the establishment of any mineral exploration project, and subsequently on the success and benefits of such projects, both to the investors and the state. A case study of the Bushveld Minerals Ltd Mokopane Iron-Vanadium-Titanium Project in Limpopo Province, South Africa is used to demonstrate the importance of pre-competitive data sets. This project acquired data from the Council of Geosciences and such data included regional geochemical data, regional geological data (geological logs, historic drill core and assay data), regional aeromagnetic and radiometric data, geological maps and some technical reports. The data was processed, integrated and was used to establish the initial exploration targets. Any follow up exploration activities were based on this initial data. This project now prides itself with JORC compliant resources and reserves of 298Mt of vanadium ore across three parallel overlying magnetite layers – the MML (Main Magnetite Layer), the MML Hanging Wall and the AB Zone, with grades ranging from 1.6% to over 2% V2O5. Secondly, examples from other parts of the world including Northern Ireland, Canada, Burkina Faso, Namibia, have been discussed to complement the Case Study. In the end, the research report shows that exploration jurisdictions that have pre-competitive data freely available have high inward investment rate as compared to those without any data. It also shows that the availability of such data sets helps to reduce the exploration expenses incurred by the prospective investors in their operations but at the same time boosting returns for the state because of the high number of inward coming investment. Following the concluding statements, the report also emphasizes implementation of procedures that have been used by countries that have been successful in increasing their inward exploration investment. Such procedures as relinquishing of all data to the state by companies that have ceased their operations, and also continual data collection exercises by the state. This means continuation of geological mapping in unmapped areas, continuation of soil geochemical sampling in areas that have not been sampled, and conducting of additional regional geophysical surveys. The conclusion of this research report simply agrees with Hronsky, 2016 who states “Give them data and they will come”.
  • No Thumbnail Available
    Item
    Increasing geotechnical data confidence through the Integration of laser scanner face mapping data into the Sishen iron ore mine geotechnical database
    (2018) Russell, Timothy Michael
    Face mapping is a simple but invaluable means of geological and geotechnical data acquisition whereby intact rock properties, rock mass properties, discontinuity properties and structural orientation can be assessed. Although traditionally done via direct contact with the mapping face through techniques such as line mapping or window mapping, remote face mapping using various digital techniques has become increasingly popular in recent years. Sishen Mine is a large open pit mining operation requiring a comprehensive geotechnical data set to evaluate pit wall design and stability with the necessary level of confidence. Geotechnical borehole data, face mapping data, geotechnical lab testing data and implicit structural models provide the main sources of this information. Although a large geotechnical borehole database has always been maintained at the mine, face mapping has in the past been restricted to sporadic and isolated stability assessments. In 2013 the mine acquired a Maptek 8810 terrestrial laser scanner with the resolution, photographic capabilities and software required to carry out geotechnical face mapping. The aims of this research project were to evaluate the capabilities of the Maptek scanner and system, set up a standard face mapping procedure, integrate face mapping data in the mine’s geotechnical database and compare face mapping acquired rock mass data with the mine’s existing borehole data set. Further potential uses for the laser scanner system and face mapping data were also explored throughout the course of the dissertation. A face mapping procedure was set up and faces were mapped from 86 individual scans, acquired between October 2015 and April 2017. The mapping data obtained from the scans was integrated into the Acquire Geological Data Management System, a purpose designed Structured Query Language (SQL) database system used for storing the mine’s geotechnical data. Open Database Connectivity (ODBC) database links with the Micromine Computer Aided Design (CAD) package allowed for spatial overlays of mapping data with other geotechnical data as well as survey and mine planning data. In terms of data analysis mapping parameters such as joint spacing, Rock Quality Designation and Rock Mass Rating could be directly compared with borehole logging values for the same rock types. The comparison indicated that in general borehole measurements tend to slightly under estimate joint spacing and rock mass rating values while face mapping assessments tend to slightly over estimate these values. This is due to various intricacies of the two data capture techniques that tend to skew the data in one way or the other. Face mapping data was compared with Sishen’s existing structural model, which is based mainly on interpretation and implicit data. Structural orientations and features correlate well between the implicit model and actual mapped values gathered during the data collection phase of this project. Within the geotechnical design process, having actual mapping data in combination with increased confidence in the structural model allows for better definition of geotechnical design sectors. Overall the face mapping and geotechnical analysis features of the Maptek 8810 terrestrial laser scanner make it an invaluable geotechnical data capture tool, providing a system is in place to store mapping data in a manner that allows for meaningful rock mass and structural information to be produced.
  • No Thumbnail Available
    Item
    Explicit and implicit geological modelling methods on resource definition and resource utilisation - Sishen iron ore deposit case study
    (2017) Deacon, Jacques
    Technological advances make geological modelling easier and more intuitive than ever before. There is a clear shift in the mining industry concerning the needs of the geological model and its function. Geological modelling is one of the first steps in the resource evaluation process; its primary function is to define the orebody’s physical properties and characteristics. It can, therefore, be argued that the geological model has a commanding impact on the entire resource evaluation process. Although many publications exist regarding modelling conventions, few truly compare the explicit versus implicit approaches and document the observed differences. This case study on the Sishen iron ore deposit shows that modern implicit modelling techniques can create geological models comparable to those created using traditional wireframing techniques. In many aspects, these implicit models are superior to their explicit counterparts due to their increased modelling speed and multiple data source inclusion. The implicit modelling process delivered a geological model with modelled ore volumes equivalent to those of the traditional explicit geological model. However, spatial reconciliation between the explicit and implicit versions of the Sishen geological models showed substantial discrepancies due to fundamental differences in geometry and connectivity, and modelling conventions. These differences in the geological models are manifested in considerable change in the final, defined Sishen resource. This case study for the Sishen iron ore deposit confirms that geological models are critical to the entire resource definition and extraction process. Any resource evaluation and planned extraction activity is only as accurate as the geological model used to define the resource originally. This study also shows how critical it is to test geological model performance through the entire mining value chain. Basic volumetric comparisons or tonnage reconciliations can mask the effects of geological modelling approaches on resource definition and extraction.