Том 44, № 1 (2021)
Chief Editor’s Column
Information for the Authors
Earth sciences and subsoil use. 2021;44(1):6-7
6-7
Geology, Prospecting and Exploration of Mineral Deposits
Mixed crystalline basement of Junggar basin revealed by wide-angle seismic evidence
Аннотация
A wide-angle seismic reflection / refraction survey along a ~ 600 km long transect through the Junggar basin from Emin to Qitai allows to receive several images near N-S trending blind faults, which are located at the lower part of the upper crust, the middle crust and the lower crust within the basin and cut up the Moho. These faults, with high seismic velocity and without obvious dislocation, are considered as “extensional faults” formed by north-south compression and east-west extension. These deeply rooted faults provide channels via which basic to ultra-basic materials from upper mantle migrate into the crust and mix up with the crustal material causing thin thickness, high seismic velocity, high density and high magnetic intensity after cooling in the crust of the basin.
Earth sciences and subsoil use. 2021;44(1):8-29
8-29
Identification of Osinsky horizon organogenic structures by 2D and 3D seismic survey data in the north-eastern part of the Nepa-Botuoba anteclise
Аннотация
The fields of Eastern Siberia belong to the one of the main centers of hydrocarbon production in the eastern part of Russia. The main part of hydrocarbon reserves is located in the area within the Nepa-Botuoba anteclise, where the Lower Cambrian deposits are major production objects. The main purpose of this research is to provide a detailed study of the inner space and features of organogenic structures of the Cambrian period, as well as to determine the procedures for detecting reef structures by seismic research methods. Statistical processing of the available factual material on reservoir properties has shown a very uneven distribution of cavernosity (porosity). It is found that pores were formed as a result of leaching of shaped formations in loose packing locations of epigenetic dolomite grains, along the cementing substance in the intergranular spaces, along cracks and stylolite seams. To identify organogenic structures in the Osinsky horizon of the Nepa-Botuoba anteclise on the basis of seismic studies some additional methodologies have been selected. Identification of single reef structures in the Osinsky horizon of the Lower Cambrian based on the analysis of seismic amplitudes was carried out by means of a 2D and 3D seismic survey. According to the data of seismic studies, the Nepa-Botuoba anteclise features the development zones of both linear and single carbonate structures. It is also revealed that there is an increase in effective thicknesses in wells located in the annular anomaly. Summing up the results and analyzing the compared materials, it can be concluded that the main identification method of ring zones in wells is the method of longitudinal wave slowness measurement. A comprehensive analysis of 2D and 3D seismic survey data by the common depth point method as well as by a number of other methods using a specific algorithm allowed us to identify individual formations of organogenic (riphogenic) structures in the carbonate section of the north-eastern part of the Nepa-Botuoba anteclise.
Earth sciences and subsoil use. 2021;44(1):30-38
30-38
Surface structure of Amur region high grade native gold
Аннотация
The purpose of the research is to study the surface structure of high grade gold. The subject of research is gold ore fields in the Amur region. The object of the study is samples of native high grade gold grains from these fields. The study uses the methods of thermodynamics and X-ray electron microscopy. The study results in revealing a multilayer structure of the surface of high grade minerals of the Amur region native gold with the following levels: a boundary layer with zero oxidation degree Au0 in the form of yellow metallic gold; an oxide layer with the oxidation degree Au+1 in the form of purple Au2O; an oxide layer with the oxidation degree Au+3 in the form of a yellow-brown Au2O3; a hydrated oxide layer with the oxidation degree Au+3 in the form of a red-yellow-brown Au(OH)3. The methods of electron microscopy have allowed to identify external surface structures – dense oxide layers of the form of Au2O3 and loose hydrated layers of the form of Au(OH)3, whereas the inner layers of metallic and monovalent gold are not visible. Important thermodynamic characteristics of the presented levels are the values of standard oxidation-reduction potentials (E°), which determine their physicochemical properties: for metallic gold E° = +1.68 V; for the oxide layer with the oxidation degree Au+1 in the form of Au2O – E° = +0.32 V; for the oxide layer with the oxidation degree Au+3 in the form of Au2O3 – E° = +1.36 V; for the hydrated oxide layer with the oxidation degree Au+3 in the form of Au(OH)3 – E° = +0.7 V. The results of the conducted studies indicate that the surface structure has several layers that lower the oxidation-reduction potential, which explains the generation and formation of migratory forms of gold in humid hypergene conditions of natural environment.
Earth sciences and subsoil use. 2021;44(1):39-47
39-47
Gemological and mineralogical-petrographic study of the Eastern Sayan serpentinites
Аннотация
The purpose of the research is to study the mineralogical and petrographic characteristics of the Eastern Sayan serpentinites in order to identify their most decorative varieties. The objects of the study are the samples of serpentinites from the Ulan-Khodinskoye and Khokhurtovskoye deposits of the Eastern Sayan. Six samples were studied macroscopically then polished plates were made from them for gemological examination and thin sections for microscopic examination. All studies were carried out using standard gemological methods at the Gemmology Research Laboratory of the Irkutsk National Research Technical University. The petrographic study of thin sections was carried out using an Axio Lab A1 microscope. Macroscopically, two main ornamental varieties of serpentinite were identified: spotted bluish-green serpentinite and massive serpentinite of the color from dark green to black. The spotted structure of serpentinite is determined by numerous inclusions of ore minerals including magnetite and iron oxides. Its hardness is 4.5 on the Moh’s scale, its gloss is matte. The data on the main gemological characteristics of the samples corresponding to the results of already published studies of gem-quality serpentinites from other deposits were also obtained. Having analyzed the microstructure and mineral composition of the Eastern Sayan serpentinites, their correspondence to the spotty and massive decorative varieties of serpentinites from other Russian deposits was revealed. At the moment, this material is not duly appreciated, although it may well be used as a sculptural and jewelry-ornamental decorative stone.
Earth sciences and subsoil use. 2021;44(1):48-55
48-55
Exploration and Development of Mineral Deposits
Improving design and application method of screening bucket excavators
Аннотация
The purpose of the study is to increase the productivity and economic efficiency of mining operations using screening bucket excavators on the basis of the introduction of a new technical and technological solution that expands equipment functionality. The study involves the analysis of known designs of screening buckets installed on excavators that ensure material separation to be carried out simultaneously with excavation and loading works. It is noted that a promising development direction of screening buckets is a design with working drums. The article presents an excavator with a modernized screening bucket and its operation technology, which allows to start rock mass sorting in the bucket while the excavator is turning to the place of unloading. The improved screening bucket is equipped with a hinged movable bottom controlled by hydraulic cylinders to accumulate fine fractions screened through the working drums. Fine fractions accumulated in the moving bottom are unloaded into a dump truck, after which screening continues directly into the body of the dump truck. Screening finished, the movable bottom closes and the excavator unloads the coarse fractions remaining in the bucket into another vehicle. Unloading is carried out by bucket turning. The combination of screening and excavator turning reduces the operation cycle time, which increases the performance of both the excavator and dump trucks. The use of a modernized screening bucket with a moving bottom eliminates the loss of valuable fine material as a result of spilling when the excavator turns for unloading. The movable bottom can be installed on the screening buckets of known designs and does not require their significant alteration. Application of the proposed technical and technological solution will reduce unit costs and increase the efficiency of work.
Earth sciences and subsoil use. 2021;44(1):56-62
56-62
Geoecology
Hydrodynamic and hydrostatic forces as factors affecting tailing dump stability
Аннотация
The study of the processes occurring deep in the earth's crust has always been a relevant research topic. The results of these studies allowed development and safe mining of mineral deposits in various conditions. The growth in the consumption of extracted resource and the increase in the scale of mining are forcing enterprises to search for the solutions to complex engineering and technical problems, one of which is the problem of displacement of rock masses and the earth's surface in industrial production-affected areas including tailings dams. The purpose of this study is to improve the operation safety of tailing dams. The object of the study is embankment dams of dressing plant tailing dumps. The subject of the study is deformation processes occurring in dam bodies and slope surfaces. The main research methods used in the work are: the study of safe operation methods for tailing dams based on the operating conditions of Uchalinskoye tailing dump using the modern methods of stability assessment, analysis and generalization of domestic and foreign experience, as well as the study of current methods of geomechanical monitoring of deformation processes – engineering and geological, geophysical, mine surveying and hydrogeological ones. The article describes geographic, hydrographic, climatic, geological and mining operation conditions of the tailing dump of Uchalinsky GOK (Ore Mining and Processing Plant) JSC. The influence of hydrodynamic and hydrostatic forces on embankment tailing dam stability is substantiated. Based on the data obtained and the research methods used, it is concluded that hydrodynamic and hydrostatic forces are fundamental destructive factors affecting dams. The results of these studies can be applied at the design stage of hydraulic structures, since they will supplement theoretical knowledge about the impact of liquid waste on the safety of tailing dams and earth-filled dams, as well as allow detecting deformation processes at their initial development stage and making decisions on their elimination.
Earth sciences and subsoil use. 2021;44(1):63-72
63-72
Hydrogeology and Engineering Geology
Predicting groundwater rise in historical centres of Eastern Siberian cities
Аннотация
The purpose of the research work is to develop a procedure for on-line prediction of the groundwater hydrodynamic mode change caused by the barrage effect of deep foundation structure construction. The main method used is the development of an analytical model as a result of variant solutions of the Laplace equation. The solutions have been elaborated in the course of studies conducted in historical centers of Irkutsk and other cities of Eastern Siberia. As a result, diagrams predicting the formation depth of groundwater level have been created, and the territories have been assessed according to their flooding conditions. An analytical model has been developed for backwater prediction. The model is rather simple, universal and can be applied for predictive calculations on the territories of historical cities located in similar geological and hydrogeological conditions. The available material analyzed, it is concluded that preliminary vertical planning of the territory, correct approach to foundation type selection as well as seasonal rise of underground water play a significant role in the formation of a new headwater elevation.
Earth sciences and subsoil use. 2021;44(1):73-84
73-84
Articles
Information for the Authors
Earth sciences and subsoil use. 2021;44(1):85-89
85-89