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

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

Referencing technique for phase detection in eddy current evaluation

This paper presents an eddy current testing (ECT) method with a different type of referencing technique for crack detection in carbon steel plate by using two Anisotropic Magnet Resistance (AMR) sensors to detect and evaluate the artificial cracks and to study the output signal's characteristics of each technique. The experiment setup of the magnetic scanning device and the measurement mode is included. Based on these three techniques that have been used, it shown that differential technique with the condition of the required reference signal must be dynamic from one point to one point was the best way to implement in the ECT method. The line scanning results indicate that performing these three techniques can be used to estimate the position of the slits, however, for 2-D mapping, it is shown that the differential technique is a preferable technique where it can remove the noise response, and at the same time, it generates a clear image of the crack. It is predicted that the developed ECT probe using a differential technique can be used as a technique to estimate the characteristic of defects in a metal plate.

WIRELESS METHANE DETECTOR WITH TEMPERATURE MODULATED HEATING PROFILE

The results of development of an autonomous methane detector in a dynamic measurement mode are presented. Industrial catalytic sensor was used as a sensitive element. To prevent burnout of the catalytic sensor microheater which often occurs during pulsed heating, the special form of heating pulse has been developed. The proposed dynamic mode of the sensor heating provides the measurements with low power consumption and the required level of safety in the measurement range of pre-explosive methane concentrations from 0.1 to 2 vol.%. Based on the analysis of the obtained results, the estimation of autonomous operating time of the detector is given.

A Generalizability Analysis of the Meaning in Life Questionnaire for Chinese Adolescents

The level of meaning in life not only affects the physical health of individuals, but also is closely related to their mental health. At present, many self-reported questionnaires are being used to measure the meaning in life of Chinese adolescents. Using the multivariate generalizability theory, this study investigated the psychometric properties and the internal structure of the Meaning in Life Questionnaires (MLQs), the most widely used questionnaire for assessing the level of meaning in life of Chinese adolescents. The data were sample of 1,951 junior high school students from Guizhou, China. Multivariate random measurement mode p × i° is the primary analytic approach. Results showed that the generalizability coefficient and dependability index of the scale were 0.86 and 0.85, respectively. The generalizability coefficients of presence of meaning and search for meaning were 0.76 and 0.85, respectively, and the dependability indexes were 0.75 and 0.85 for MLQ-P and MLQ-S, respectively. The design of each factor for MLQ is reasonable in terms of score ratio and the number of projects. In brief, the reliability and factor structure of the scale are satisfactory.

Portable microwave radiometer for wearable devices

This paper presents a new circuit of the miniature microwave radiometer for wearable devices, which can be used to monitor the core body temperature (CBT) of internal human tissues continuously 24/7. The measurement results of the proposed device, as opposed to the known miniature wearable radiometers, remain unchanged when the impedance of the examined area varies. We have derived an analytical expression for radiometer measurement error based on parameters of device components. This formula allows accuracies to be estimated and optimal parameters of the circuit to be selected to minimise measurement error at a design stage. It is shown that measurement error is independent of the antenna reflection coefficient and the temperature of the radiometer front-end. A prototype of the single-channel miniature radiometer has 32 х 25 х 14 mm3 dimensions and USB interface communication with PC. A 28-hour run of the device has shown that it is highly stable, and a maximum drift in temperature is 0.15 ̊C. Operating frequency range was 3400-4100 MHz, supply voltage - 5V; power supply of the radiometer in measurement mode is 210 mA; time constant of the radiometer without being averaged is 0.6 sec, at the same time, standard deviation δ = 0.17 ̊С, with further averaging during 4 sec δ=0.052 ̊С, with averaging during 30 sec δ =0.017 ̊C; when there were input reflections R2=0.25, an error in measuring brightness temperature shifted by 0.2 ̊ C; with 10 ̊C variations in ambient temperature the shift was 0.15 ̊C. Introduction of self-contained power supply and wireless communication with smartphone have made it possible to use the proposed radiometer as a wearable device to monitor the temperature of internal tissues and CBT during human activities.

Optimization of 2-D Magnetotelluric (MT) Modes Based on Data Dimensionality to Delineate Potential Area for Shale Gas Prospect in Kutai Basin, East Kalimantan, Indonesia

We conducted a study using the magnetotelluric method in the Kutai Basin, which is one of the largest and deepest tertiary sedimentary basin located in the province of East Kalimantan, Indonesia. The Kutai Basin, which is one of the sedimentary basin that is proven to produce hydrocarbons in Indonesia, also has the potential for shale gas with all the complexities of its geological structure. Inversion of 2-D MT can generally be done in three modes with different sensitivity. We perform data processing objectively to obtain the best quality data. We continued our data processing to the inversion process with a range from 80.78% to 97.09% coherency data. We also performed sensitivity skewness calculations to determine the dimensionality of our data. The map of sensitivity skewness is shown for the vertical path A – A’ with direction N – S in our study area. Based on the calculation results, the skewness value below 0.3 is obtained around the frequency 320 - 0.002 Hz, and associated with the 2-D structure while value above 0.3 are obtained around the frequency 0.00198 - 0.00034 Hz at KT34 and KT36 stations. Based on dimensionality calculations, it is concluded that the MT data in the Kutai Basin is dominated by 2-D structural responses, so that the TE + TM (invariant) mode is the best measurement mode for inversion modeling. We also performed calculations to obtain the optimum smoothness factor (tau) using a trade-off curve. Based on the results of the inversion with the optimization of these data parameters, we obtained a subsurface geological structure pattern such as fault and fold structure along the vertical path of A – A’. The low resistivity anomaly is interpreted as a response to the presence of black shale which is part of the Pamaluan Formation. The top of the Pamaluan Formation is estimated at the depth that varies from 2000m to 4000m below the surface along the A – A’ vertical cross-section.

Impact of a Robot Manipulation on the Dimensional Measurements in an SPC-Based Robot Cell

In our study a robot was used to deliver objects for measurement into the Equator gauging system. To investigate the robot’s manipulation influence on dimensional measurements, the robot’s tasks were divided into basic functions. Based on these basic functions, nine different robot-manipulation scenarios were defined, i.e., from zero to full robot manipulation, for two measuring objects (named Magnet and PKR) and six measurement characteristics (rectangular and spherical). The robot’s manipulation influence was determined on the basis of the statistical parameters Cp, R, and the 6σ obtained from a measurement system analysis (MSA) type-1 study. The results show that the degree of implemented manipulation of the robot affects the scattering of the measurement data. However, the effect is much more pronounced in the case of length measurements than with spherical geometries. Different measuring methods (touch-triggering or scanning measurement mode, number of sampling points) were used, which showed similar measurement data. This directly indicated the influence of the robot’s manipulation on Cp, R and 6σ. Increasing the degree of the robot’s manipulation decreases the Cp value and increases the R and 6σ values for the length measurements. There is no such pronounced course in the spherical geometries, where the values of Cp, R and 6σ remain approximately the same. The main influential factor for decreasing the Cp value with increasing robot manipulation was the angular misalignment of the object’s orientation in the fixture.

Development of a generalized mathematical model of static error electromechanical measuring equipment

To keep military equipment fit for use, carry out maintenance activities, an important and integral part of which is metrological service. The effectiveness of metrological services depends on the completeness of the coverage of the monitored parameters, frequency and reliability of their measuring control. The most common, at present, when controlling the parameters of military equipment are electromechanical measuring equipment. The main metrological characteristic of electromechanical measuring instruments in a static measurement mode is the nominal calibration characteristic. During operation, the calibration characteristic of electromechanical measuring instruments, under the influence of various factors, has deviations from the nominal, which leads to an instrumental static error. The article deals with the applied aspects of assessing the static error of electromechanical measuring equipment, which is expressed through the sensitivity or static transmission coefficients of measuring transducers. Based on the results of the analysis, a generalized mathematical model of the relative static error of electromechanical measuring equipment for various structural schemes of connecting measuring transducers was obtained. It is proposed to apply a generalized mathematical model to assess the relative static error of electromechanical measuring instruments (with various structural schemes) during their operation. The use of an updated static error will allow to refine the calibration characteristics of electromechanical measuring instruments, which in turn will lead to obtaining reliable information about the state of military equipment during metrological maintenance and immediately before use.

First results of a promising Doppler lidar configuration to derive wind gusts within the FESSTVaL campaign

<p>A central aspect of the Field Experiment on Sub-Mesoscale Spatio-Temporal Variability in Lindenberg (FESSTVaL, www.fesstval.de) is the investigation of wind gusts with Doppler lidar measurements. Compared to meteorological tower observations, they have the advantage of being able to probe higher altitudes of the atmosphere, they thus offer the possibility to record a vertical profile of wind gusts with a resolution of about 30 m in the atmospheric boundary layer. Nevertheless, it is difficult to capture wind gusts with these instruments as it is challenging to measure fluctuations of short duration with an instrument which needs a certain time for one complete measurement.</p><p>Based on the research of Suomi et al. (2017), different configurations were tested in a pre-campaign in autumn 2019 to identify a suitable measurement mode for Halo Photonics Stream Line Scanning Doppler LiDAR systems. Different lidars were operated in parallel to compare configurations against each other. A promising mode was tested during the FESST@MOL campaign in summer 2020 for a three month period. This is a continous scan mode (CSM) configuration that takes about 3.4 seconds per circulation and performs measurements in 10-11 directions.</p><p>The derived wind gusts and mean wind speeds are compared with high resolution sonic anemometer measurements at 90.3 m to verify the quality of the lidar measurements. In a first comparison good agreement is shown despite the different measuring principles. In addition, various parameters are tested to identify optimal thresholds that allow a reliable derivation of wind gusts.</p><p>In summer 2021 this fast CSM mode will be operated and further tested in the FESSTVaL campaign in parallel with UAS measurements. Moreover lidars will be installed at different locations to analyse the spatial characteristics of wind gusts with this scanning configuration.</p><p><strong>Reference</strong></p><p>Suomi, I., Gryning, S.‐E., O'Connor, E.J. and Vihma, T. (2017), Methodology for obtaining wind gusts using Doppler lidar. Q.J.R. Meteorol. Soc., 143: 2061-2072. https://doi.org/10.1002/qj.3059</p>