scholarly journals Comprehensive analysis and assessment of prospective gold-ore zones using modern geophysical methods

2021 ◽  
Author(s):  
И.И. Босиков ◽  
Р.В. Клюев ◽  
В.Х. Тавасиев ◽  
Н.Н. Летичевская
Keyword(s):  
Magnetic Field ◽  
Electrical Resistance ◽  
Geophysical Methods ◽  
Technical Specification ◽  
Comprehensive Analysis ◽  
Polarization Method ◽  
Ore Bodies ◽  
Measurement Mode ◽  
The Magnetic Field ◽  
Ore Zones

В статье рассматривается комплексный анализ геологической и геофизической информации по проводимым исследованиям с целью выделения перспективных участков для проведения дальнейших геологоразведочных работ. Цель работы. Провести комплексный анализ и оценку перспективных золоторудных зон с применением современных геофизических методов. Методы работы. Вертикальное электрическое зондирование методом вызванной поляризации, метод вызванной поляризации в модификации срединного градиента, геоэлектрические разрезы по профилям, аномалии поляризуемости поля электрических сопротивлений, метод ТЗ электротомографии. Результаты работы. Авторами в 2019 г. в северной части участка на площади 2,87 кв. км были выполнены работы СГ-ВП по сети 50×10м с MN – 10 м. и АВ – 2000 м. Измерения DU и φвппроводились на частоте 1.22 Гц измерителями МЭРИ – 24 и ЭИН – 209 (режим измерения частотный). Использовался генератор ГЭР – 5000 – 25 (мощность 5 кВт). По результатам измерений построены карты изолиний поляризуемости и кажущегося сопротивления. Следует отметить, что при определении сдвига фаз φвп в частотном режиме сигнал, используемый для измерения сдвига фаз при равных DU с импульсным режимом измерений в 30-100 раз выше. Это основное преимущество фазовых измерений над импульсными. Как видно из приведенного сравнения уменьшение длины приемной линии и шага наблюдений позволило увеличить детальность исследований СГ-ВП и выйти на уровень рудных тел, заданных в техническом задании. По результатам ТЗ электротомографии и ВЭЗ-ВП получены близкие результаты, хотя методически и теоретически ТЗ обладает в данных условиях большей детальностью и информативностью. По результатам геофизических работ построены карты изолиний и графиков ρк и φвп, выявлена их связь с рудовмещающими структурами и отдельными рудными телами. Всего выявлено 14 локальных аномалий поляризуемости связанных с золото-кварц-сульфидными и сульфидными рудными телами. Выявлены площадные аномалии повышенной поляризуемости и низких значений электрического сопротивления СГ-ВП вдоль Западной рудно-тектонической зоны. Они связаны с метасоматическими процессами в пределах Западной зоны сбросо-сдвигов. На площади работ отмечены слабоконтрастные аномалии магнитного поля в северо-западной части Северной зоны. Отмечено сильное влияние рельефа на характер магнитного поля, вследствие чего наблюдается корреляция хребтов с минимумами магнитного поля. The article discusses a comprehensive analysis of geological and geophysical information on ongoing research in order to identify promising areas for further exploration. Aim. Conduct a comprehensive analysis and assessment of promising gold ore zones using modern geophysical methods. Methods. Vertical electrical sounding by the induced polarization method, the induced polarization method in the modification of the median gradient, geoelectric sections along the profiles, anomalies of the polarizability of the electrical resistance field, TK method of electrotomography. Results. The authors in 2019 in the northern part of the site on an area of 2.87 sq. km SG-VP works were performed on a network of 50 × 10m with MN -10m. and AB - 2000 m. Measurements of DU and φvp were carried out at a frequency of 1.22 Hz with meters MARI - 24 and EIN - 209 (frequency measurement mode). Used generator GER - 5000 - 25 (power 5 kW). Based on the measurement results, maps of isolines of polarizability and apparent resistivity were constructed. It should be noted that when determining the phase shift φvp in the frequency mode, the signal used to measure the phase shift at equal DU with the pulse measurement mode is 30-100 times higher. This is the main advantage of phase measurements over pulsed ones. As can be seen from the above comparison, a decrease in the length of the receiving line and the step of observations made it possible to increase the detail of SG-VP studies and to reach the level of ore bodies specified in the terms of reference. Based on the results of the technical specification for electrotomography and VES-IP, similar results were obtained, although methodologically and theoretically, the technical specification has greater detail and information content under these conditions. Based on the results of geophysical work, maps of isolines and graphs of ρк and φвп were constructed, their relationship with ore-bearing structures and individual ore bodies was revealed. In total, 14 local anomalies of polarizability associated with gold-quartz-sulfide and sulfide ore bodies have been identified. Areal anomalies of increased polarizability and low values of electrical resistance of SG-VP were revealed along the Western ore-tectonic zone. They are associated with metasomatic processes within the Western fault-strike zone. Low-contrast magnetic field anomalies in the northwestern part of the Northern Zone were noted in the survey area. A strong influence of the relief on the nature of the magnetic field was noted, as a result of which a correlation of the ridges with the minima of the magnetic field is observed

scholarly journals Reconstruction of German Coastal Defense Line in 1942-1944 and Search for Military Historical Heritage Objects. Bolshoi Tyuters Island. Data of Geophysical Methods and Excavations.

2021 ◽  
pp. 144-161
Author(s):  
Aleksandr L'vovich Borisik ◽  
Evgeniy Vladimirovich Pyatigorskiy
Keyword(s):  
Magnetic Field ◽  
Sand Dunes ◽  
Geophysical Methods ◽  
Observation System ◽  
Metal Debris ◽  
Coastal Defense ◽  
Historical Heritage ◽  
Short Time ◽  
High Degree ◽  
The Magnetic Field

The article describes the results of full-scale geophysical 2017-2018 studies conducted with the purpose of detecting military historical heritage objects on Bolshoy Tyuters Island. Sand dunes located in the eastern part of the island were studied in a short time by detailed magnetic exploration with an observation step of about 1 m. The most interesting anomalies of the magnetic field were investigated with the georadiolocation method. The processed results provided for mapping the anomalous magnetic field and creating georadiolocation sections and a dimensional relief model which demonstrate anomalies related to German defense and are promising for further excavations. The pinpoint excavations of the identified anomalies made it possible to explain their nature and discover objects of historical value at depths of up to 5 m. Despite high "contamination" of the dunes with metal debris, the use of geophysical methods with a dense observation system made it possible to detect a large number of objects of military historical heritage and significantly reduce the volume of excavations. Linking of the German positions archival scheme at hand additionally provided for comparing the location of the objects found with symbols made on it. After systematization and generalization of all the information obtained during 4 years of research on the island, it is possible to reconstruct the system of German defense in the area of sand dunes with a high degree of reliability.

scholarly journals Application of in situ digital holography to the study of the effect of a magnetic field on the anodic dissolution of iron in thichloroacetic acid

2006 ◽  
Vol 71 (1) ◽  
pp. 67-73 ◽  
Author(s):  
Xuegeng Yang ◽  
Shenhao Chen ◽  
Chao Wang ◽  
LI. Liang
Keyword(s):  
Magnetic Field ◽  
Acid Solution ◽  
Anodic Dissolution ◽  
Potentiodynamic Polarization ◽  
Trichloroacetic Acid ◽  
Digital Holography ◽  
Polarization Method ◽  
Trichloroacetic Acid Solution ◽  
The Magnetic Field

The effect of a magnetic field on the anodic dissolution of iron in 1.0 mol dm-3 trichloroacetic acid solution was studied by the potentiodynamic polarization method and in situ digital holography. It was found that the magnetohydrodynamic force increased the mass transport, which resulted in a faster anodic dissolution of iron. The effect of the magnetic field was analyzed by holograms and is discussed in terms of the magnetohydrodynamic force.

scholarly journals Analysis of Electrical Resistance and Impedance Change of Magnetorheological Gels with DC and AC Voltage for Magnetometer Application

Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2510 ◽  
Author(s):  
Jae-Eun Park ◽  
Ga-Eun Yun ◽  
Dae-Ik Jang ◽  
Young-Keun Kim
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Electrical Resistance ◽  
Input Voltage ◽  
Impedance Change ◽  
Resistance Change ◽  
Capacitance Variation ◽  
Resistance Variation ◽  
Impedance Modeling ◽  
The Magnetic Field

Magnetorheological gel (MRG) is a smart material that can change its stiffness property by external magnetic field and has been applied as a smart rubber in suppressing vibration. Recent studies show that the electrical resistance of MRG also can be affected with external magnetic field. Thus, this study aimed to conduct analysis on MRG resistance variation due to external magnetic field with DC and AC input voltage. With an DC input voltage, the resistance change due to magnetic field was modeled. In addition, the capacitance variation of the material was observed. The impedance of MRG due to AC input voltage was analyzed and was observed that the impedance of MRG was affected by both the magnetic field and the input frequency. With the experiment data, the impedance modeling of MRG in frequency domain was derived. Based on experiment results, the performance and limitation of MRG as a magnetometer sensor are discussed.

Galvanomagnetic and thermomagnetic phenomena

2004 ◽  
Author(s):  
Robert E. Newnham
Keyword(s):  
Magnetic Field ◽  
Heat Flow ◽  
Magnetic Fields ◽  
Hall Effect ◽  
Electric Current ◽  
Lorentz Force ◽  
Electrical Resistance ◽  
Magnetic Flux Density ◽  
Wide Range ◽  
The Magnetic Field

The Lorentz force that a magnetic field exerts on a moving charge carrier is perpendicular to the direction of motion and to the magnetic field. Since both electric and thermal currents are carried by mobile electrons and ions, a wide range of galvanomagnetic and thermomagnetic effects result. The effects that occur in an isotropic polycrystalline metal are illustrated in Fig. 20.1. As to be expected, many more cross-coupled effects occur in less symmetric solids. The galvanomagnetic experiments involve electric field, electric current, and magnetic field as variables. The Hall Effect, transverse magnetoresistance, and longitudinal magnetoresistance all describe the effects of magnetic fields on electrical resistance. Analogous experiments on thermal conductivity are referred to as thermomagnetic effects. In this case the variables are heat flow, temperature gradient, and magnetic field. The Righi–Leduc Effect is the thermal Hall Effect in which magnetic fields deflect heat flow rather than electric current. The transverse thermal magnetoresistance (the Maggi–Righi–Leduc Effect) and the longitudinal thermal magnetoresistance are analogous to the two galvanomagnetic magnetoresistance effects. Additional interaction phenomena related to the thermoelectric and piezoresistance effects will be discussed in the next two chapters. In tensor form Ohm’s Law is . . .Ei = ρijJj , . . . where Ei is electrical field, Jj electric current density, and ρij the electrical resistivity in Ωm. In describing the effect of magnetic field on electrical resistance, we expand the resistivity in a power series in magnetic flux density B. B is used rather than the magnetic field H because the Lorentz force acting on the charge carriers depends on B not H.

scholarly journals The resistance of superconducting cylinders in a transverse magnetic field

1938 ◽  
Vol 166 (924) ◽  
pp. 43-55 ◽  
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Electrical Resistance ◽  
Applied Field ◽  
Transverse Field ◽  
Transverse Magnetic ◽  
Superconducting Cylinder ◽  
A Value ◽  
The Magnetic Field ◽  
Field Penetration

Experiments on the penetration of a magnetic field (de Haas and Casimir-Jonker 1934) into superconductors have shown that, when a superconducting cylinder is placed in an increasing transverse field, penetration of the field first occurs when the applied field strength reaches a value 0·50 H k , where H k is the critical field corresponding to the temperature of the experiment. Since, for this value of the applied field, the field strength, at the surface of the cylinder (von Laue 1932) where it is intersected by a diametral plane perpendicular to the direction of the field, will be precisely H k , the above result is in accordance with expectation. On the other hand, it was found by de Haas, Voogd and Jonker (1934) that under the same conditions the cylinder first exhibited electrical resistance when the applied field strength reached the value 0·58 H k . Since this discrepancy probably results from the properties of the “intermediate state” (Peierls 1936; London 1936; Landau 1937) occurring when the magnetic field just begins to penetrate the superconductor, it seemed desirable to investigate the matter in more detail.

Geology and geophysics of the Underground Research Laboratory site, Lac du Bonnet Batholith, Manitoba

1989 ◽  
Vol 26 (2) ◽  
pp. 404-425 ◽  
Author(s):  
A. Brown ◽  
N. M. Soonawala ◽  
R. A. Everitt ◽  
D. C. Kamineni
Keyword(s):  
Magnetic Field ◽  
Research Laboratory ◽  
Geophysical Methods ◽  
Low Frequency ◽  
Magnetite Content ◽  
Em Field ◽  
Underground Research Laboratory ◽  
Canada Limited ◽  
The Magnetic Field ◽  
Eastern Half

The lease area of the Atomic Energy of Canada Limited Underground Research Laboratory covers 3.8 km2 and is located 2.5 km north of the south contact of the Lac du Bonnet Batholith. A shaft to 255 m and 130 boreholes up to 1100 m deep expose the third dimension.The underlying granite is largely of two types: (i) pink porphyritic, which may be biotite rich, gneissic, and (or) xenolithic; and (ii) grey homogeneous and equigranular. Composition layering, including xenolith-rich zones, outlines domes along an antiform trending north-northeast through the western part of the lease area. The southeast-dipping flank underlies the eastern half of the site, including the shaft. Axes of folding trend 065 °and 140°. Homogeneous grey granite, being relatively fresh and unfractured, is associated with a magnetic field that is about 100 nT higher and with a resistivity that is up to 5000 Ω∙m higher than those of other units. A pattern of highs in the magnetic field, caused by the high magnetite content of some xenoliths, can be used to map the antiform.Three thrust faults that dip 10–30° east-southeast are partly controlled by the compositional layering. Anomalies in the very low frequency electromagnetic (VLF-EM) field occur at the surface projections of faults. One fault has been mapped at depth by a high-resolution seismic reflection survey. A suite of downhole geophysical methods, including cross-hole seismic, has been used to map discontinuities in boreholes.Subvertical penetrative foliations and pegmatitic dykes are part of the late crystallization fabric, providing (with filled fractures) a continuous deformation history in response to north- to northeast-trending compressive stress.

scholarly journals The theory of the magneto-resistance effects in metals

1947 ◽  
Vol 190 (1023) ◽  
pp. 435-455 ◽  
Keyword(s):  
Magnetic Field ◽  
Electrical Resistance ◽  
Low Temperatures ◽  
Lorenz Number ◽  
Strong Magnetic Fields ◽  
Pass Through ◽  
Set Up ◽  
Magneto Resistance ◽  
The Magnetic Field ◽  
Overlapping Bands

General formulae are obtained for the effect of a magnetic field on the electrical and thermal conductivities of a metal in which there are two overlapping bands of normal form. Simple formulae are set up which, though not strictly valid for all temperatures and fields, reduce to the correct expressions in the three limiting cases of high temperatures, low temperatures and very strong magnetic fields. The behaviour of the electrical resistance at low temperatures is discussed, and it is shown that in certain cases the resistance may pass through a minimum as the temperature is increased provided the magnetic field is large enough. It is also shown that in general the Lorenz number is increased by the presence of a magnetic field, but that the thermal conductivity of the lattice is unaffected by a magnetic field.

scholarly journals Синтез тонких пленок ниобия на кремнии и исследование их сверхпроводящих свойств в области размерного кроссовера

2021 ◽  
Vol 91 (2) ◽  
pp. 275
Author(s):  
И.В. Янилкин ◽  
А.И. Гумаров ◽  
А.М. Рогов ◽  
Р.В. Юсупов ◽  
Л.Р. Тагиров
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
Electrical Resistance ◽  
Three Dimensional ◽  
Specific Effect ◽  
Two Dimensional ◽  
Superconducting Transition ◽  
Conduction Electrons ◽  
The Magnetic Field ◽  
Coherence Lengths

Niobium films of 4–100 nm thickness were synthesized on a silicon substrate under ultrahigh vacuum conditions. Measurements of electrical resistance showed a high temperature of the superconducting transition Tc, in the range of 4.7–9.1 K, and extremely small transition widths ΔTc in the range of 260–11 mK. The dependences of Tc and ΔTc on the magnetic field were studied, and superconducting coherence lengths and mean free paths of the conduction electrons were determined for different thicknesses of the synthesized films. A specific effect of the magnetic field on ΔTc was found, which reveals a transition from three-dimensional to two-dimensional superconductivity at thicknesses below 10 nm. The dependences of Tc and ΔTc on the films thickness and the magnitude of the magnetic field are discussed in the framework of existing concepts of superconductivity in thin films of superconducting metals.

London Penetration Depth of Fe-Based Superconductors

2014 ◽  
Vol 979 ◽  
pp. 297-301 ◽  
Author(s):  
Arpapong Changjan ◽  
Pongkaew Udomsamuthirun
Keyword(s):  
Magnetic Field ◽  
Free Energy ◽  
Penetration Depth ◽  
Electrical Resistance ◽  
Critical Magnetic Field ◽  
London Penetration Depth ◽  
Iron Compounds ◽  
Ginzburg Landau ◽  
The Magnetic Field ◽  
Very High

Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in certain materials when cooled below a characteristic critical temperature. Fe-based superconductors are superconductors whose containing iron compounds and having a very high critical magnetic field. London penetration depth can assist in the study of the behavior of the critical magnetic field. The London penetration depth is the distance to which a magnetic field penetrates into a superconductor and becomes equal to 0.367879 times that of the magnetic field at the surface of the superconductor. In this paper, the London penetration depth of Fe-based superconductors is studied by Ginzburg-Landau scenery. Free energy of Fe-based superconductors is assumed by modified the free energy of two-band magnetic superconductors model and theof Fe-based superconductors is derived analytically. Finally, the temperature dependence of is investigated and applied to Single-Crystal superconductors.

Sign in / Sign up

Export Citation Format

Share Document