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Engineering and Mining Geophysics 2021
- Conference date: April 26-30, 2021
- Location: Online
- Published: 26 April 2021
61 - 80 of 184 results
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Prospects for Passive Seismic Methods for Monitoring the Railway Base in Areas with Difficult Soil Conditions
Authors I.P. Orlova, N.K. Kapustian and G.N. AntonovskayaSummaryBased on the experience of using broadband seismic equipment for monitoring the soil of the base of the railway track for the Northern Railway using the train as a sounding signal source, its unique capabilities for detecting changes in the state of soils at an early stage are shown. The possibility of monitoring the condition of the soil of the base of the roadway with passive seismic methods has been experimentally shown and confirmed by modeling. Field observations showed that recordings at low frequencies (0.01 Hz) significantly differ in neighboring sections of the path — favorable and unfavorable, with the horizontal components being the most informative. Records at frequencies of 2 - 8 Hz are characterized by significant changes in the ratio of the amplitudes of the vertical and horizontal components during seasonal watering. The obtained experimental results are consistent with modeling. The possibility of identifying the stages of freezing and thawing of the soil and the associated negative processes is discussed.
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Induced Polarization and Transients at High Frequencies-Field Experiments
More LessSummaryThe experience of our application of measurements of induced polarization and transients at high frequencies suggests that this method can be used in solving a number of geoengineering problems (mapping the geo-base of buildings and structures, identifying and delineating zones of fracturing, flooding, quicksand, landslide-prone areas, etc.), problems of ore geology (mapping ore veins and mineralized zones, raft, sand and peat in placer deposits, etc.).
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Induced Polarization of Metallic Particles in The Temperature Range from 10 to – 20°C: First Results of Laboratory Studies of Synthetic Models
Authors G. Gurin, V. Emelianov, D. Popov and K. TitovSummaryInduced Polarization method (IP) is the leading method of mining geophysics because it allows detecting disseminated ores, which frequently can serve as indicator of economically valuable deposits. In Russia, most of mining districts actively investigated with IP method, are located in Far East and Eastern Siberia. At such cold regions rocks are temporarily or permanently frozen. However, to date, only scares data concerning IP of frozen disseminated ores are available. In this paper we studied low-frequency (from 10 mHz to 100 Hz) spectral IP (SIP) of synthetic models of disseminated ores made with a mixture of sand and cryptomelane. We carried out SIP measurements in the temperature range from +10⁰С to -25⁰С in the course of successive decrease and increase of the temperature. In addition we measured SIP response at the reference model made with the sand alone. Four regions were detected in the relationship between the absolute value of the complex resistivity and temperature. With decrease of the temperature (1) the resistivity slightly increases at the positive temperature range following the linear trend; (2) the resistivity strongly increases when the temperature goes down from zero to -2 – -3 ⁰С; (3) with further increase of the temperature up to -10 – -15 ⁰С the resistivity continues to increase with slower rate, following an exponential trend; and (4) with further increase of the temperature up to 20 0 C the resistivity follow again the exponential trend, but with smaller coefficient of the exponent. In the third region we detected a hysteretic behavior of the ‘resistivity – temperature’ relationship. We obtained very similar results with the samples contained the water saturated sand alone. With increase of the temperature the maximum value of the complex resistivity phase decreases, and, in contrast, the IP relaxation time increases. These relationships also show hysteresis. We explain these hysteretic behaviors of the studied parameters by (1) a decrease of the water saturation in the course of water freezing, (2) a rise of salt into pore water from appeared ice phase, and (3) a different dynamics of ice melting and water freezing. We believe the aforementioned phenomena lead to different tortuosity of the liquid phase when the temperature decreases and increases. Our data show that the IP magnitude characterized by the complex resistivity phase, decrease twice comparing to the unfrozen sample, when the sample temperature is about -10⁰С. We believe that at - 10⁰С the free water is completely frozen. We state, therefore that at negative temperature the IP effect does not disappear, but their magnitude strongly reduces, which must be considered when planning IP surveys and analyzing IP data at cold regions.
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The Experience of Refraction and CDP Reflection Method for Dam Structure Investigation
Authors A.M. Turchkov, A.N. Oshkin and A.A. VyaznikovtsevSummaryThe results of refraction and CDP reflection method survey are described in the present work. Investigation of the structure of dam was the main survey objective. The present proceedings contain the field data acquisition, processing and interpretation technique.
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Development and Manufacture of a Deepsea Drilling Complex for Offshore Geological Exploration
Authors D.A. Nasonov, A.V. Grigorchuk, M.A. Voronov, D.V. Kaminskiy and V.B. MalinSummaryKey stages of development and manufacture of a test prototype of a deepsea drilling complex of a revolving type for offshore exploration activities up to 6000 m sea depths are addressed.
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Application of a Three-Dimensional Modification of The Guided Empirical Mode Decomposition Method in Geophysical Field Approximation
Authors V.A. Voroshilov and V.I. KosticynSummaryThe paper describes features of three-dimensional modification of GEMD decomposition. A comparison of the distribution of local extrema of 3D EMD with “characteristic points” of GEMD is presented. It’s shown that the approximation construction obtained by GEMD allows to reach robust results of 3D decomposition. The location of approximating sources in space and in depth during area modification of decomposition allows to use them for creating rank approximation constructions. This approach allows to use GEMD for approximation of essentially nonstationary signals.
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Engineering and Geological Features of The Weathering Crusts of Copper-Pyrite Deposits (on The Example of The «Saum» and «Tamuner» Deposits)
Authors T.S. Bobina and I.V. AbaturovaSummaryDeposits and occurrences of copper are extremely common in the earth's crust, have a different origin and are formed in a variety of geological and tectonic settings. The search and exploration of such deposits, the creation on the basis of their long-term, large mining enterprises is one of the most promising and priority tasks for the country's extractive industry. Near the surface of copper-pyrite deposits, the formation of weathering crusts of different properties is characteristic. That is why Russia is now beginning to become one of the most interesting test sites for studying weathering crusts of various types. And the analysis of the engineering and geological features of the weathering crusts will be an important accent in solving the urgent problem of conducting open pit mining - forecasting and substantiating the stable parameters of the pit slope angles. The choice of the development system, preparation of working horizons and their parameters and indicators of the stability of open pit slopes, as well as reducing the risk of hazardous processes in the sides of the open pit, will largely depend on the optimal solution to this problem.
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Induced Polarization of Saturated Ion-Conducting Rocks and Soils: Mechanistic Models
Authors K. Titov, G. Gurin, B. Mehalli and A. TarasovSummaryIn this paper, we review phenomenological and physical-chemical theories of Induced Polarization (IP) of saturated ion-conducting rocks and soils. The IP phenomenology is based on a behavior of equivalent electrical scheme including parallel connection of two elements: (1) a resistance, and (2) a serial connection of another resistance and capacitance. This scheme can be described based on a very popular Pelton [1978] model. Then we review two classes of physical-chemical theories, describing the granular and the capillary models of rock/soil. Both are based on the theory of Electrical Double Layer (EDL) occurring at the interface between the solid and liquid phases. In the granular model IP is mostly produced by the polarization of the inner part of EDL (the Stern layer), and in the capillary model – by the membrane polarization, which, in turn, is closely related to polarization of the outer part of EDL (the diffuse layer). In conclusion, we address two methodological principles of IP modelling: (1) experimental determination of a dominant IP physical mechanism typical of each rock/soil type, and (2) theoretical modelling of such a mechanism using minimally needed measurable parameters.
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Field Tests of The POS-Aero Quantum Overhauser UAV Magnetometer-Gradiometer Designed for Geophysics and Archaeology
SummaryThe results of field tests of the POS-Aero Overhauser gradiometer, which has no analogues in the world, are presented. We performed multiple flights on a linear route at different altitudes, as well as area surveys over a weak magnetic area and over a car. Errors of gyroscopic measurements during rotation of the DJI 600 hexacopter are investigated. The accuracy of the maps of the total field of 1 nT and the gradient of 0.1 nT/meter is shown. The proven universal magnetometer is promising for ground-based and unmanned geological exploration and the search for hidden objects. The weight of the kit reaches 1–1.5 kg, providing a sensitivity of up to 0.03 -0.15 nT at rate of 1–0.3 sec.
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Improving The Computational Efficiency of 3-D Modeling of Induced Polarization in Airborne Time-Domain Electromagnetic Problems
Authors M.G. Persova, Yu.G. Soloveichik, D.V. Vagin, A.S. Kiseleva, A.P. Sivenkova and E.I. SimonSummaryThe article proposes mathematical models for calculating induced polarization (IP) when solving 3-D airborne time-domain electromagnetic problems. The proposed approaches are optimized directly for solving “multisource” problems for further application in data processing systems. For constructing finite element approximation, we use optimized non-conforming hexahedral meshes allowing to drastically reduce the number of degrees of freedom while keeping the required solution accuracy. In addition, to provide calculations with a large number of positions of the transmitter-receiver set, the space-time grouping of subtasks corresponding to different positions of the airborne system and parallelization were used. We present a comparison of the developed computational schemes that perform calculations both directly in the time domain and in the frequency domain, as well as a comparison with the results of other authors. It is shown that the solutions obtained using different approaches are in good agreement with each other. The computational costs required for calculating the electromagnetic field taking into account the IP effects in a complex 3-D medium with topography are about 10 s per position. This will make it possible to use this approach in the future in systems for processing airborne data.
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Airborne Geophysical Surveys with Ultralight Aircraft in The Search and Evaluation of Deposits
Authors P. Babayants, O. Kontarovich and A. TrusovSummaryThe possibility of performing detailed surveys on promising small size areas is discussed. It is proved that airborne geophysical surveys are an effective means of optimizing the search by reducing the volume and precise positioning of drilling. The effectiveness of work with unmanned aircraft carriers is discussed. As an alternative, shooting with ultra-small manned aircraft is considered.
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Induced Polarization of Rocks with Electronically Conductive Inclusions: Laboratory Study of Synthetic Capillary Models of Consolidated Rocks
More LessSummaryIn this paper, we present results of laboratory investigation of Induced Polarization (IP) carried out with synthetic capillary models of consolidated rocks. The models contain metallic particles blocked capillaries. We studied how the volumetric content of metallic particles, their size, electrical conductivity, active surface (in contact with capillary water), as well as the electrical conductance of the capillaries and the conductivity of the capillary solutions affect IP phase spectra, chargeability and relaxation time. We introduced a new parameter, the effective concentration of active particles. By substitution this parameter for the volumetric content of metallic particles in the Maxwell-Garnet equation we obtained a good agreement between the experimental data and the theory. We also evidenced a not-linear IP effect obtained with reasonable small applied current value. We also found that the relaxation time depends on the total conductance of the model capillaries, the conductivity of metallic inclusions, and their active surface (in contact with capillary water). These founding contradicts with the respective results obtained with granular models, when the relaxation time depends on the EM inclusion radius and the pore water conductivity. These new data highlight electrochemical mechanism of IP of metallic particles, and hold the hypothesis concerning charging of the capacity of the electrical double layer at the interface between electronically conductive inclusion and capillary water as the main cause of the polarization.
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Economic Efficiency Assessment of Geophysical Site Survey for Offshore Oil and Gas Facilities Development
Authors D. Lalomov, D. Baidikov, D. Korshunov and G. KovalenkoSummaryImplementation of investment construction projects on the shelf is a business with a high level of risk, due to geohazards, which are a potential source of harm to offshore oil and gas facilities. With a certain combination of probability and harm, potential geohazards turn into risks and should be considered not only in the framework of geophysical site survey, but also from the point of view of project risk management. Due to this purpose the results of engineering-geophysical site survey are reviewed from the point of geohazard risk management for offshore oil and gas facilities construction. Based on the actual methodology for quantitate risk analysis using the risk-approach, the economic efficient of geophysical site survey is assessed. It is an important criterion for customer informed investment decisions.
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Inspection of The Sludge Tank Dam Using Electrical Exploration
Authors A. A Tainickiy, Ju. I Stepanov, M.S. Luchnikov and E.S. BushuevaSummaryThe dam survey was performed using the three-spaced SEP method to identify inhomogeneities in soil conductivity. The data obtained as a result of geological and geophysical research can be considered a sample of one or several random variables. This allows to analyze their statistical characteristics and increase the amount of useful information contained in observations. Statistical analysis of data was performed for precise localization of areas of low resistance. It made it possible to identify intervals of reduced resistance and to determine the area of the possible presence in the body of the investigated dam of a gully, which was formed during a breakthrough by a water flow.
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Possible of Using GPR and Electrical Tomography for Landslide Studies in The Quarry of Open Pits Mines in The Permafrost Zone
Authors K.O. Sokolov and R.A. DyagilevaSummaryThe article is devoted to the study of the possibility of studying landslide processes on the sides of the permafrost quarries using geophysical methods for the purpose of a more detailed and continuous study of the rock mass. Prospective methods for studying geocryological conditions are considered to be such methods as GPR and electrical tomography. To determine the zones of weakening by the GPR method, a physico-geological model of the rock mass of rock ledge side of the pit permafrost zone was created, represented by the seasonally thawed layer and frozen sand, with the inclusion of layer ice watered from above. The electrophysical properties of rocks were selected according to various literature sources and field data obtained at the Kangalassky coal mine (Central part of the Republic of Sakha (Yakutia)). Based on the developed model, a computer simulation of ground-penetrating radar measurements was carried out using the gprMax software. The analysis of the amplitude values of GPR signals reflected from the base of the seasonally thawed layer showed the possibility of detecting landslides at the stage of initiation.
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GPR Studies of The Permafrost Conditions of the Main Pipeline Area in Western Yakutia
Authors D.V. Savvin, L.L. Fedorova, G.A. Kulyandin and E.E. SolovievSummaryWhen building and operating linear engineering structures in the permafrost zone it is important to take into account the engineering-geological conditions of the site of their location, the state and properties of the bearing soils. Under the conditions of the development of permafrost rocks, a complex mechanical and thermal effect of engineering structures on the natural environment occurs, leading to the activation of potentially dangerous cryogenic processes with a negative impact on engineering structures, including main pipelines. One of the most effective ways to study these negative processes is geophysical methods, which make it possible to quickly assess the state and properties of soils, identify lithological differences, boundaries of frozen and thawed rocks, identify talik zones, ice inclusions, etc.
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Highway Diagnostics by GPR Method in Cryolitic Zone Based on Example of Federal Highway «Vilyui» Section
Authors L.L. Fedorova, D.V. Savvin and M.P. FedorovSummaryExperimental research was carried out in order to improve diagnostics methods of roads operated in cryolitic zone. Results of ground-penetrating radar diagnostics at the Vilyui federal highway in Central Yakutia are presented. Data was obtained by OKO-2M GPR with AB-400 antenna unit (LogiS LLC). Attributes for interpretation of GPR wave fields are developed based on characteristics of GPR signals propagation in the road soils. Further it is used for mapping various cryogenic structures. For example, to identify water invasion zones at boundaries of the structural layers of the road surface and the roadbed, to determine zones of soil decompression at the subgrade support, to identify areas of swelling soils. As a result, GPR monitoring as part of engineering and geological survey allows reasonably plan and carry out actions to eliminate and prevent various types of subsidence and destruction of road surfaces, as well as to assess the nature and level of negative cryogenic processes.
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Identification of Technogenic Pollution of soil Environment by The GPR Method
Authors G.A. Kulyandin, M.P. Fedorov, D.V. Savvin and L.L. FedorovaSummaryThe specific conditions of cryolithozone make it difficult to conduct engineering surveys for construction, especially in the zone of the spread of technogenic-contaminated soils. To carry out measures to stabilize the soil of the bases during the construction of engineering structures, it is necessary to know the location of weak and polluted soils. The solution of such problems is possible with the use of modern technologies. For example, by the method of GPR. The report provides an example of a GPR survey of a road construction site on an area previously used for storing household waste. The geophysical work was carried out in winter, at the established extremely low ambient temperatures (below -45°C) using the georadar “OKO-2M” with the antenna unit AB250M (center frequency 250 MHz). According to the GPR data, interpretation attributes of structural inhomogeneities of soils associated with the presence of various debris are determined. Based on the results of areal geophysical work, GPR sections were obtained with isolated soil inhomogeneities associated with man-made pollution on an area of more than 90 000 m2. Based on these data, a map of the distribution of man-made pollutants in the soil was constructed using the geostatistical spatial interpolation method “Kriging”. The total volume of polluted (non-uniform) soils is calculated based on the data provided by GPR.
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GPR Assessment of The Channel Capacity on Congestion Sections of Rivers in The Pre-Spring Period
Authors L.L. Fedorova and M.P. FedorovSummaryOn most rivers of Russia, during opening, ice jams are formed annually, which reduce the throughput of the channel, accompanied by a rapid increase in water level rises, leading to dangerous floods. To predict the formation of ice jams, information is needed on the thickness of the ice and the relief of the channel, on which the process of moving ice plates along the river during the spring flood depends. At present, the GPR method allows obtaining information about the thickness of the ice, the structure of the ice cover, the morphometry of the channel and the thickness of bottom sediments. For the study of the ice situation on the Lena River in the alignment of the Tabaga hydrological station, the method of complex GPR studies of the river channel in the summer and the ice cover of the river at the end of freeze up was applied. As a result, a cross-sectional profile of the river channel was obtained, in which the ice cover was in contact with the sandy sediment. This contact of ice with sediment can be a potential obstacle to the advancement of spring floods or a source of spring ice jam formation.
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Estimation Inverse Velocity Section Response on Seismic Wavefield
Authors V.V. Romanov, V.I. Ryzhkov and K.S SergeevSummaryA feature of inverted velocity sections is the presence of a low-thickness high-velocity surface layer (PVL). Such a layer can be formed by seasonally frozen and technogenically compacted soils, concrete and asphalt pavements [1, 6]. Observed on seismograms, observed according to the Y - Y observation scheme. Unlike normal sections, Love waves are not traced in inverse sections, since the conditions for their occurrence are not met. This circumstance allows us to identify useful reflected waves confined to the boundaries in the depth range from the first meters to the first hundreds of meters.
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