Browsing by Subject "electromagnetic profiling"

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Access status: Open Access ,
The application of electromagnetic methods for polymetallic prospecting in mining conditions
(Wydawnictwa AGH, 2017) Gołębiowski, Tomisław; Żogała, Bogdan; Mendecki, Maciej; Małysa, Tomasz
The paper presents selected results of geophysical surveys carried out in the »Polkowice-Sieroszowice« copper mine in Lower Silesia, Poland. The aim of complex geophysical measurements was the analysis of the usefulness of selected electromagnetic methods for locating ore mineralisation zones in mining conditions. The results were obtained from surveys conducted along profiles designed on the side-wall by the roof, in the middle and the floor of the excavation. Electromagnetic Profiling and Ground Penetrating Radar techniques were applied for outlining the mineralisation zones consisting of Cu, Pb and Fe. The variability of geophysical recordings depending on the degree of mineralisation and distribution of fractures induced by mining activity were analysed. The results of geophysical surveys were correlated to petrophysical parameters and laboratory data concerning the percentages of Cu, Pb and Fe in samples taken from the side-wall at the survey site.
Access status: Open Access ,
The contribution of geophysics to archaeology: a case study of an ancient canal of the Oc Eo culture in the Mekong Delta, Vietnam
(Wydawnictwa AGH, 2019) Lê, Ngọc Thành; Nguyễn, Quang Dũng; Nguyễn, Quang Bắc; Nguyễn, Quang Mien; Nguyễn, Dan Vu; Duong, Ba Man; Nguyễn, Dinh Chau
Generally, underground ancient canals are infilled with alluvial materials, with the canal bed and substrate often having different resistivity values. This study aimed to determine the location and morphology of Malleret’s ancient canal 16 located to the southeast of the Ba The mountain, Mekong Delta, Vietnam by means of geophysical techniques. Two geophysical methods were used: electromagnetic profile and electric resisitivity tomography. A geoelectric structure 70 m long with 70–95 mS/m of apparent conductivity was found. On the electrical resistivity tomography section, a resistivity zone of 10–20 $\Omega \cdot$ m, 1-4 m deep, 70 m wide corresponds to the mentioned above geoelectric structure, which is in an asymmetric U-shape extending toward the southeastern bank of canal 16. Hand-augering confirmed that the canal bed is fully incised into Holocene sediments as a substrate which stretches down to the Pleistocene. The sediments are composed of loams mixed with plant remains with a resistivity ρ ~ 10–15 $\Omega \cdot$ m. Both of the canal banks at a depth of 5 m are made up of Holocene sedi-ments ($\rho$ ~ 4–10 $\Omega \cdot$ m). The $^{14}$C measurements determined the age of the organic matter in the canal as being equal to 1210 $\pm$ 85 BP, suggesting canal 16 ceased being operational at that time. The precise positioning of canal 16 on the ground surface, as well as identifying the morphology of the canal bed, were corroborated by geophysical techniques. The obtained results are of considerable value to archaeologists.