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2nd Conference on Geophysics for Mineral Exploration and Mining
- Conference date: September 9-12, 2018
- Location: Porto, Portugal
- Published: 09 September 2018
61 - 68 of 68 results
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Reflection Signal Detection Algorithm for Desert Seismic Data Based on Gaussianity Testing
More LessSummaryThe pathway for getting high accuracy seismic data is to effectively attenuate the random noise existing in the seismic records. However, in desert seismic data processing, the performances of the conventional noise attenuation methods sometimes are not as good as expected due to the low fundamental frequency of the random noise. Here, a novel reflection signal detection algorithm based on Gaussianity analysis is proposed. The basic idea of the proposed algorithm is to extract the efficient reflection information by utilizing the differences between the random noise and the reflection signals in terms of the Gaussianity. The Jarque-Bera test is used to investigate the Gaussianity of the seismic data. By analyzing the test statistics, the reflection signals could be detected. The experimental results indicate that the proposed algorithm can track the reflection signals well. The finding also has further implications for noise reduction and seismic signal processing algorithms.
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Enhancing Potential Field Data Using TDY Filter
Authors A. Nasuti, Y. Nasuti and D. MoghadasSummaryPotential field methods produce anomaly maps with different magnitudes and depths that are typically contaminated by noise, making them hard to interpret. In order to highlight edges of the anomalies with different depths and magnitudes, data filtering techniques have received a great attention, in particular for mineral explorations. Filtering approaches render to explore more details from potential field data maps. In this respect, high pass filters are commonly used for enhancing the anomaly edges all of which utilize gradients of the potential field. In order to apply different filters on the potential field data, major attempts have been made to make a balance between noise and the signal obtained from a filtered image ( Cooper & Cowan, 2006 ).
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Can Heat Flow Be Related with Pyrite Content and Location in the Iberian Pyrite Belt (Portugal)?
By M.R. DuqueSummaryThe heat flow density and temperature data obtained in part of the South Portuguese Zone in Portugal are analyzed in this work. Part of the Iberian Pyrite Belt is located in the region studied. The heat flow values are higher than average values found in continental regions and the excess of heat found can not be provided by radioactivity sources in the region like uranium, thorium and potassium. The excess of heat is obtained considering that the anomalous sources of heat are located in a uniform layer with a thickness of 6 Km. The difference between the average value of heat sources and the radioactivity sources (D-A) is directly related with the heat flow values measured in the region. High thermal gradient values can be found in neighboring regions with low thermal conductivity values suggesting the existence of lateral heat transfer. It is suggested that the excess of heat is due to chemical reactions involving oxidation of pyrite ores abundant in the region. At the end a question is made. Why not use the heat flow in the detection of pyrite bodies in the region ?
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Geological Remote Sensing in Challenging, Vegetated Terrain and under Thin Cover
Authors S. Breed and M. GoossensSummaryGeological remote sensing can be used for structural and stratigraphic mapping in complex geological environments, such as vegetated terrains, and areas covered by thin layers of recent deposits. In vegetated areas, changes in river patterns and subtle changes in vegetation type and density, are the main aspects that aid the understanding of the geological setting. In areas of limited outcrop that have a thin cover of recent sediments, indirect surface expressions of structures can be accurately mapped with remote sensing data.
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Direct-Prospecting Methods for the Areas with Gold Mineralization Detection in Zone of “Klinsy” Deposit in Ukraine
Authors S.P. Levashov, M.A. Yakymchuk, I.N. Korchagin and D.N. BozhezhaSummaryThe results of approbation of ground-based geoelectric methods, as well as frequency-resonance technology of satellite images processing at the local site of the Klintsy gold deposit in Ukraine and in the larger tectonic zone of its location are analyzed. Experimental studies have shown that geoelectric methods of the forming a short-pulsed electromagnetic field (SCIP) and vertical electric-resonance sounding (VERS) can be used for the search and mapping of ore objects of different mineralization. The direct-prospecting method of satellite images frequency-resonance processing allows you to obtain operatively new information about the prospects of finding objects with ore (gold ore) mineralization within the large search areas. Ground-based detailed work can be carried out within the limits of the mapped anomalies, both by traditional geophysical methods, and with application of SCIP and VERS geoelectric methods. In the tectonic zone of the Klintsy deposit location, four promising objects for gold ore mineralization have been discovered, which deserve detailed study by geological and geophysical methods. The use of mobile direct-prospecting methods for solving a wide class of problems of ore geophysics will facilitate the acceleration of the exploration and prospecting process for ore minerals of various types.
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3D Reflection Seismics for Deep Platinum Exploration in the Bushveld Complex, South Africa
Authors M. Manzi, A. Malehmir and R.J. DurrheimSummarySeismic methods have become, and will continue to be, an important tool to help unravel structures hosting mineral deposits at great depth. This work demonstrates how the reflection seismic method (mainly 3D seismics) has been successfully used to explore some of the world’s largest platinum deposits and map the gross structural architecture that controlled the formation of these ore bodies, support mine planning and contribute to safety. A case study from the Bushveld Complex in South Africa is presented, demonstrating the importance of advanced 3D seismic attributes for high-resolution structural mapping.
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Presenting Non-Invasive and Fully Acceptable Exploration Technologies - The INFACT Project
Authors A. Viezzoli, S. Roffey, C. Wijns, I. Fernandez and J.M. Blanco GonzalezSummaryDespite its rich history of mining and residual mineral wealth, current conditions within the EU present a number of social, political, legislative, cost, technical and physical obstacles to raw material exploration: obstacles to be overcome by innovation, dialogue and reform. The Innovative, Non-invasive and Fully Acceptable Exploration Technologies (INFACT) project, within the Horizon 2020 program, will work to mitigate each and every one of these obstacles.
Specific to exploration geophysics, the project will facilitate development of innovative airborne geophysical and remote sensing technologies (less-invasive than classical exploration methods) that promise to penetrate to new depths, reach new sensitivities and resolve new parameters. The project will also set the EU as a leader on the world stage by establishing permanent infrastructure (reference sites) to drive innovation in the next generation of exploration tools: tools that are cost-effective, designed for EU conditions and its raw materials strategy, and high-performing in terms of minimum environmental impact, social acceptability, and technical performance. These reference sites will provide long-term targets over which successive new technologies can be tested against previous ones
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A Joint Geophysical and Geochemical Survey in the Old Braçal-Malhada Mining District (NE Aveiro, Portugal)
Authors V. Valente, A. Martins, J. Martinho, J. Ribeiro, C. Patinha, F. Almeida, E. Silva and M. MatiasSummaryThe Braçal –Malhada mining region, 30km NE of Aveiro included several silver-lead mines that operated until mid 20th century. Mineralization consists on sulphides (galena, sphalerite, pyrite) in quartz veins occurring in the complex Porto-Tomar shear zone, Fig. 1 . Veins develop in a 10km wide area, show different orientations, are found in granites, schists and even quartzite, and can pass through different rock types with no alteration. Exploration work in the area dates from the 1950’s and 70’s.
This study compiles recent geological mapping, preliminary regional geochemical and geophysical surveys. It aims to obtain a general information on the area, delineate regions for further studies, that is, fieldwork with closer grids, complementary methods (such as electromagnetics, induced polarization), etc.
Because of space limitations, only selected maps are given herein. Geophysics consisted on preliminary magnetic and gravimetric mapping. Residual, gradient, second derivative and Euler deconvolution magnetic and gravimetric maps were produced, interpreted against known geology, tectonics and interesting features for further exploration work are revealed.
A stream sediments sampling geochemical campaign, overall 101 samples, was carried out and allowed identifying the main geochemical association of elements.
Finally, geophysical and geochemical data are integrated to provide an enhanced view of the area.
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