The method of active plaque is becoming dominant in the methodology of emanation.
The grading of field logging f-spectrometers is an important but poorly developed issue. Usually it is performed in f-saturated media modeling the conditions of measurements in boreholes.
Gamma-spectral logging to separately determine the concentrations of natural radioactive elements emerged and formed in the USSR as a new radiometric method in the mid-60s. Thanks to the works mainly of the radiometric laboratory of the LGI, this method is widely recognized and successfully applied in prospecting and exploration of radioactive ore deposits. Its main advantages over geologic sampling of well cores are in efficiency, cost-effectiveness and the ability to fully investigate the well regardless of the core yield ...
The effective mass attenuation coefficients of gamma ray attenuation of radioactive ores have close values for the integral spectrum measured by the NaI(Tl) scintillator in a standard screen, and for the energy windows used in gamma-ray spectral logging and ore sampling ...
Interest in the study of the behavior of K in the zone of hypergenesis has become particularly important in connection with the widespread introduction of gamma-spectrometry in the practice of prospecting for ore deposits, which makes it possible to obtain information on the distribution of K in loose sediments over large areas and use these data in various geological and geochemical constructions ...
Anomalous changes in concentrations due to scattering halos are often comparable in their parameters with fluctuations of the geochemical background and with its changes due to the change of rocks. In these cases, it is necessary to use such a method of processing the survey results, in which the geochemical background, carrying information about the geological structure or regional geochemical patterns, is distinguished from the field of measured concentrations, and local anomalies of prospecting interest are identified
The logging gamma-spectrometer developed and tested by us contains three counting-resolving channels providing continuous recording of gamma equivalent concentrations of U, Tb and K, and an integral channel. The counting-resolving channels can be used in the mode of continuous or discrete recording of the average pulse frequency in specified energy windows ...
In the predictive evaluation of ore-bearing areas, the researcher faces two tasks - what to look for and where to look? A sufficiently clear answer to this can be obtained if the entire set of geological, geophysical and geochemical data is used, and the nature of these data and their relative role depend on the stage of prognostic assessment.
Partial exit of radon into the well, subjected to prolonged flushing during drilling, leads to a decrease in the intensity of radiation along the axis of the well and underestimation of linear uranium reserves according to gamma logging data.
The most promising method of sampling of uranium-thorium ores, which allows separate determination of uranium and thorium, is the gamma-spectral method in modification of measurements of the difference effect of radiation. The principle of such sampling is considered earlier...
Continuous recording of equivalent contents of radioactive elements instead of registration of count rates in differential channels during gamma-spectral measurements allows to quickly obtain information on the distribution of elements in the studied object and simplify the processing and interpretation of results. This method is used for search gamma-spectral surveys in motion. We have used continuous recording of uranium (by radium) and thorium contents in gamma-spectral logging at the site of two-component uranium-thorium ores.
The different spectral composition of gamma radiation of uranium and thorium ores determines the specificity of taking into account the attenuation of radiation in casing pipes and washing fluid when interpreting gamma-spectral logging diagrams.
Head of the Department of Geochemical and Radioactive Exploration Methods, Professor, Doctor of Geological and Mineralogical Sciences Nikolai Konstantinovich Morozenko was a communist, a major scientist, one of the best experts in the geology of rock crystal deposits and natural riches of Central Asia, Pamir and Altai.
Gamma-spectrometry is increasingly used in the sampling of uranium-thorium ores. It is based on measurements of pulse count rate in the optimal for uranium and thorium areas of the gamma-radiation spectrum. One of the main conditions ensuring high accuracy of sampling is the correct choice of gamma-spectrometer energy windows. This question arises most acutely at creation of spectrometric equipment with small size of scintillators in connection with low speed of counting of pulses in narrow energy windows, recommended usually in the literature.
To date, the methods of taking into account emanation in the radiometric analysis and sampling of uranium ores have been developed in sufficient detail. For thorium and uranium-thorium ores these questions are poorly studied, because it is believed that thoron has a short half-life (TTp = 54.5 sec), so it quickly comes into equilibrium with the parent substance ...
The method of accounting for thorium in three gamma ray log interpretations recommended by the existing gamma ray logging manual provides for multiple determinations of thorium in core samples. Samples are analyzed for thorium by gamma ray spectrometry or by chemical and radiochemical methods. The absence in some laboratories of stable scintillation analyzers and in field parties of logging stations that allow reliable separation of uranium and thorium in boreholes forces expensive radiochemical analyses for thorium and radium (due to the need to determine the equilibrium coefficient of uranium and radium).
