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Vol. 20 (2017 year), No. 1, DOI: 10.21443/1560-9278-2017-20-1/1

Mel'nikov N. N., Kalashnik A. I., Kalashnik N. A., Zaporozhets D. V.
The use of modern methods for complex studies of the hydrotechnical structures of the Barents Sea region

The Barents region hydrotechnical structures (HTS) as part of the bulk earth dams and levees tailings of mining enterprises in terms of requirements of the responsible entities have been considered. The brief review of emergencies and accidents of HTS with an analysis of their causes and geo-ecological consequences has been fulfilled. The necessity and urgency of the application of modern techniques for comprehensive research and monitoring of the HTS state have been shown: geo-fluid mechanics computer modeling, subsurface georadar sensing, GPS geodetic measurements, optical and radar satellite imagery. Joint use of GPR and satellite imagery in combination with traditional engineering-geological, hydro-geological and geodetic studies allows obtaining a more complete picture of the HTS state taking into account local and regional geological and fluid dynamic processes. The system structure of HTS complex researches which creates a scientific and technical basis for researching the geologic-geophysical environment, shifts, deformations and power influence has been developed. This allows to reveal the hidden filtration and deformation zones in HTS at early stages of their formation and in due time to make the administrative decision on prevention and localization of any emergency. Application of modern methods for HTS complex researches will allow to receive operational information on their state, parametrical sizes of volume, angular and linear deformations and movements, intensity of natural and technogenic influence. The obtained data have to be integrated in the "Database and Parameters" geoportal by means of which their logical processing and comparison to standard and extreme values has to be carried out. On this basis expert assessment of the current and expected state of HTS is carried out and the operating decisions including on development, in case of need, of preventive and protective measures are made.

(in Russian, стр.8, fig. 3, tables. 2, ref 11, Adobe PDF, Adobe PDF 0 Kb)

Vol. 22 (2019 year), No. 1, DOI: 10.21443/1560-9278-2019-22-1

Kalashnik A. I., Dyakov A. Yu.
Evaluation of rock disturbance by GPR sensing using water saturation for contrast

The most important element concerning efficiency and safety of developing mineral deposits is the consideration of the main structural features of the rock massif. The paper considers methodological issues of the GPR sensing application to study the internal structure of rocks. GPR surveys have been performed on a working bench of the Zhelezny mine, Kovdorsky GOK. Initially, the sensing has been performed by longitudinal profiling of the rock mass in its natural state to the depth of 20 m in combination with a telemetric survey of rock fracturing in the borehole located on the profile. Then the borehole was completely flooded with water, and GPR sensing studies have being repeated after 15, 30 and 60 minutes simultaneously with the registration of a decrease in the water level in the borehole. The GPR study results have been analysed in order to identify the effect of rocks' water-saturation on the recorded electromagnetic characteristics, and to determine the relationship of structural disturbance of rocks and their dielectric constant before and after water-saturation. It has been revealed that rock water saturation is an indicator that allows for more contrasting detection of rock disturbance zones due to the relatively insignificant difference in dielectric constant in the undisturbed and disturbed dry rock massif. The rock disturbance in an open pit slope has been estimated by GPR sensing, using water-filled borehole for contrast of measurements. The assessment has shown that water-saturated, porous, permeable, fractured rocks have higher dielectric constant values than dry / monolithic, weakly fractured rocks that have lower dielectric values permeability. It has been established that due to the water-saturation of rocks changes in the values of dielectric constant increased twice, and amounted to 0.6 units, while before saturation these changes were only 0.3 units, i. e. were two times lower. In order to substantiate the assessment of rock disturbance by GPR sensing, a comparative analysis has been made of GPR data and void of rocks in the vicinity of the borehole calculated on the basis of the filtration coefficient. The analysis has shown that the dielectric constant increases with increasing voids in the rock and, accordingly, with increasing water-saturation

(in Russian, стр.9, fig. 6, tables. 0, ref 12, Adobe PDF, Adobe PDF 0 Kb)