TN212 : Processing and interpretation of magnetic, remote sensing and geological data for exploration of iron ore deposits in northeast of Mayamey
Thesis > Central Library of Shahrood University > Mining, Petroleum & Geophysics Engineering > MSc > 2012
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Abstarct: Geographic information system (GIS), has been used since 1980, as a new tool for decision making and management in many branches of the earth sciences, including discoveries of mineral deposits at local and regional scales. This system cannot be used for solving mineral exploration problems, but it is a tool for the qualitative and quantitative analyses of data, storing and updating the data for exploratory models. GIS models and combines the results obtained from classical or conventional methods with maximum precision, speed and the least time and cost.
Due to the limitations of conventional methods, an attempt was made in this research work to use GIS with a new and improved exploration strategy.
In this research, after investigating and processing geophysical, remote sensing, geological and structural geological data of Northeast of Mayamey, suitable exploration maps to prospect and explore iron deposits in this area were extracted.
To process the satellite images, the ENVI 4.5 software, and for qualitative interpretation of magnetic survey data, the Geosoft and the Model vision Pro software, was used. Considering the type and nature of existing data, the knowledge-driven methods of index overlay and fuzzy logic were used to integrate the data. The reason for not using the data-driven methods for integration of the data in the area is that the methods need some exploration evidences and considering the lack of such evidences, the above-mentioned knowledge-driven methods were used to integrate the data.
Modeling, interpreting and expertise integration of exploration data can have an important role to improve the selection of drilling locations. Therefore, for combination of exploration laxyers, the maps were scored by the expert. Finally the GIS maps have been combined with index overlay method, gamma fuzzy operator and a new proposed method of extended fuzzy. Investigation of the obtained final GIS maps indicates that the most identified promising zones are located in an area.
As ground magnetic surveys, requested by the employer, have only been carried out in one of the promising areas, named Zeydar area, thus, detailed investigations have been made by field visit, taking geological samples and applying various processing filters on the ground magnetic data to determine the limits of the anomalies area.
In order to separate anomalies, various methods of anomalies separation including reduction to the pole, upward continuation, vertical derivative, simple analytic signal, and also, first and second order analytical signal methods were used. These studies indicate the existence of a magnetic anomaly in the area.
In addition, detailed geological studies in Zeydar area such as taking geological samples, preparing polished and thin sections of the samples, and also, analyzing the samples by XRF and ICP methods were made. The analysis results of the XRF samples show relative high amounts of iron oxide in the samples so that the iron oxide content of the iron deposit even reaches to 62%.
Furthermore, the positions of the taken geological samples have been coincided with high magnetic intensity zones in the total magnetic map of the area that implies a good agreement between the results of geological studies and magnetic surveys. These detailed studies, carried out in Zeydar area, confirm the results of the final exploration maps, obtained from the integration of the data using the index overlay, fuzzy and extended fuzzy methods.
Keywords:
#Magnetic surveys #Fuzzy method #Remote sensing #Geographic Information System (GIS) #Knoswledge-driven methods #Integration of exploration laxyers Link
Keeping place: Central Library of Shahrood University
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Keeping place: Central Library of Shahrood University
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