Volume 43, Nº 1 (2020)
Geology, Prospecting and Exploration of Mineral Deposits
Strategic minerals resources of the Republic of Buryatia: current state and development prospects
Resumo
The study is aimed at determining the current state and prospects of strategic mineral resources development in the Republic of Buryatia for use in knowledge-based high-tech industries of the Russian Federation. Comprehensive geological, geophysical and forecast metallogenic studies have been carried out based on the previously conducted geological survey, prospecting, exploration, and research work. To analyze the ores’ material composition and to establish the genetic types of the strategic mineral deposits, advanced mineralogical, petrological, geochemical, and isotope geochronological methods have been used. It has been established that the geological structure of the region is determined by its position in the folded frame of the Siberian platform south. The formation of the strategic mineral deposits of various genetic types is associated with the favorable tectonic-magmatic and ore-bearing structures distinguished in the region. Of primary commercial importance are the deposits and occurrences discovered in the region: beryllium, tungsten, molybdenum, uranium, gold, lead, silver, nickel, platinum, titanium, as well as aluminum, pure quartz raw materials, cadmium, indium, thallium, scandium, strontium, barium, rare and trace metals. The Republic of Buryatia has significant reserves of strategic metals capable to meet the needs of certain high-tech industries in the country. Over 700 mineral deposits are concentrated here, of which about 600 have been inventoried in the state balance. The study has identified over 20 types of mineral raw materials as demanded strategic resources.
Earth sciences and subsoil use. 2020;43(1):8-35
8-35
Exploration for hydrothermal geological reservoirs by geophysical methods in the Mongol-Baikal region
Resumo
The paper presents the study on the prospects of the exploration for hydrothermal geological reservoirs in the Mongol-Baikal region using geophysical methods. For the purpose of the study, the following methods have been used: transient electromagnetic sounding, vertical electromagnetic sounding, and induced polarization method. The above methods have proved effective in the selecting the objects with contrast resistivity at various depths. The low resistance (5-10 Om·m) of the hard rock can be caused by the presence of fractured zones with high-temperature mineralized solutions, i.e hydrothermal reservoirs. As a result of the surface geophysical studies carried out at different depths at the reference site (Shivert hydrotherm deposit, Arkhangai aimak, Mongolia) and at the prospective site in the vicinity of Sangiyin-Tolgoi volcano (7-8 km from the regional center Tsetserlag), hydrothermal geological reservoirs isolated from the day surface have been identified. The Shivert hydrothermal deposits with a temperature of 67 °С have been brought to the surface with shallow boreholes up to 78 m deep. At the prospective site located within the internal deflection of the Khangai synclinorium, the hydrothermal geological reservoir is at a depth of over 700 m. A 400 m deep borehole drilled in this section brought the pressure water with a temperature of up to 16 ºС to the surface in spite of the cold water influx in the lower 100-meter interval. The thermal state of the underground hydrosphere of the Khangai arch uplift has been estimated using hydrogeochemical geothermometers, based on the chemical composition of more than 20 thermal sources. The underground hydrosphere of the Khangai arch uplift with its high temperatures associated with magmatogene thermal anomaly is of great practical interest. The thermal waters of the Mongol-Baikal region are concentrated in the thermal effluent fault zones and in the presence of overlapping sedimentary deposits, do not always make their way to the day surface. The above geophysical methods are suitable for the exploration for such hydrothermal reservoirs.
Earth sciences and subsoil use. 2020;43(1):36-48
36-48
Influence of the pulse duration and transient measurement time on the display of the low-frequency dispersion of the earth’s electromagnetic properties for marine waters up to 100 m deep
Resumo
The purpose of the study is to define the influence of the pulse duration and the transient measurement time on the display of the low-frequency dispersion of the electromagnetic properties of the geological formations in the transient measurements by electric lines for marine waters not more than 100 m deep. The study has analyzed the transient signal change Δ U ( t ), finite difference Δ2 U ( t ) and transforms P 1( t ) (the ratio of the above values) as functions of the pulse duration and transient measurement time. The analysis has been conducted with a probe consisting of a source (a horizontal grounded electric line (AB) 500 m long, and a receiver (a three-electrode electric line (MON) 500 m long). The signals calculated for the conducting medium have been compared with the ones calculated for the conducting medium with a conducting polariziable base. The conducting medium is associated with the marine water mass in the shelf areas up to 100 m deep and non-polarizable geological layers. The conducting polarizable base includes geological formations that are characterized with induced polarization. The registration of the base polarization has been realized by introducing frequency-dependent electrical resistivity with the Cole-Cole formula. The calculations show that the optimum condition for the investigation of the polarization process and polarization properties of the geological environment covered with the water mass, is the use of longer-lasting pulses and signal registration till large time values. The optimum measurement condition is inducing the transient process with the pulses with the duration of not less than 4 s, and registering the signal for not less than 4 s. During the practical measurements taking place when towing the probe, the pulse duration and measurement time influence the number of the measured transients in a unit of the profile line length. Correspondingly, the pulse duration and measurement time have to be limited in order to enhance the possibility of the statistical enhancing of the useful signal. At the same time, these limitations should allow registering the display of the galvanic-induced polarization process in the general signal. The induced-polarization signal becomes predominating in the transient at later stages.
Earth sciences and subsoil use. 2020;43(1):49-58
49-58
Mineral Processing
Flotation tests of the new complex collecting agent for antimony oxide forms: a case study of the antimony ore sample from the Zhipkhosha deposit
Resumo
The purpose of the work is to study a new collecting agent for antimony oxide forms in order to reduce metal loss with the tails. The main methods for processing antimony ores are gravity and flotation beneficiation. The major amount of antimony extracted through the enrichment of various types of antimony ores is due to the presence of the metal sulfide form (antimonite). Antimony loss, in turn, is associated with oxide minerals (stibnite, valentinite, kermzite) that are present in the form of films, lenses or flakes. The only known method for extracting antimony oxides from the ores of various deposits is flotation concentration. So far, for the enterprises processing antimony ores, there are no developed schemes or regimes of flotation concentration that would allow obtaining conditioned (or close to conditioned) concentrates from oxide antimony forms. To extract antimony oxide minerals, fatty-acid collectors of the cationic type, carbon hydrogen, petroleum oils and shale resin are used. As a result of the research, a new complex collecting agent KСSb, consisting of wood-chemical products and a derivative of aspartic acid, has been selected as an effective antimony collector. A method of oxidized antimony ore flotation using a new collector reagent KСSb has been developed. The method increases the technological and economic indexes of the flotation process.
Earth sciences and subsoil use. 2020;43(1):59-65
59-65
Composition of sand samples from southwest and central areas of Transbaikalia
Resumo
A study of the characteristics of the sand samples from the southwest shore of Lake Baikal has been carried out, with the purpose to find out the possibility of using the sand for the needs of the food industry. To determine the granulometric composition of the sand, a sieve analysis method has been applied, i.e. the separation of the granular mixture fractions using a set of sieves, with the further determination of the mass of each fraction and their percentage in the test substance. The sieving has been carried out by means of vibration. The X-ray analysis of the sand samples has used a Bruker D8 Advance diffractometer. The method allows determining the parameters of the crystal lattices, analyzing the phase composition of the test substance, and identifying the prevailing structures in the sample. Based on the x-ray analysis results, the crystal structure of the mineral components has been determined. The study has shown the following mineralogical composition of the sand. The prevailing mineral is quartz, its content varying from 40 to 60 percent; the content of albite and anorthoclase is 15 to 30 percent, and a small fraction is represented by dikkit and indialit (less than 5 percent). In the sand samples taken in the settlement of Angasolka, about 9 percent is represented by antophyllite. The processed results of the sieve analysis show the following. Most samples have been found to be quite homogeneous in terms of their grain composition, each sample having a predominant fraction, with the exception of the sample taken in the town of Slyudyanka, in which the particle size varies significantly. The studied sand samples can be classified as lacustrine or lake-glacial, their crystal-chemical composition being quite diverse. The study shows that the main components in the sand composition are quartz and feldspar, with a small content of other minerals being present. The granulometric analysis results show that the sand samples taken at the lakeshore in the vicinity of Slyudyanka are characterized by a large dispersion of the particle sizes, while other samples of the bulk material contain a predominant fraction. The sand from the Baikalsk area is most suitable for use in the food industry as it contains middle size fractions.
Earth sciences and subsoil use. 2020;43(1):66-76
66-76
Exploration and Development of Mineral Deposits
Validation of the flushing fluid types used in penetrating terrigenous hydrocarbon reservoirs (Siberian platform south)
Resumo
Penetrating a reservoir is an important part of well construction. Non-quality penetration may cause clogging of the reservoir’s pore space, which in turn may lead to a low hydrocarbon debit or its absence. Searching for a solution to this problem is costly and complicated, and may eventually turn unsuccessful, leading to loss of time and money. The authors have examined the existing types of flushing fluids used in penetrating the reservoirs. The advantages and disadvantages of the fluids, as well as the degree of their influence on the reservoir rocks have been defined. Based on the data obtained, the authors have proposed a method for minimizing the negative impact of the flushing fluids on the reservoir. The method allows reducing the depth of the flushing fluid filtrate penetration in the reservoir, which increases the deliverability and life of the well.
Earth sciences and subsoil use. 2020;43(1):77-87
77-87
Mathematical programming for process optimization problems in well drilling
Resumo
Optimization problems solved by means of linear programming are presented in the form of equalities or inequalities, the target function being linear. Linear programming methods are widely used in solving problems for engineering, food industry, and chemical industry. This prevalence is due to the availability of the software for solving high-dimensionality linear programming problems and the possibility to analyze the problems when varying the source data. Constructing a linear programming model includes determining the variables of the problem, setting constraints in the form of inequalities, and representing the solution objective as a linear function. The article presents the description of the problem’s’ mathematical formulation and the specific realization of the description for the so-called ‘mixture’ problems: the mixture is the drilling mud, its technological quality being a function of the ingredients, and the preparation cost should be minimal. The construction of the problem model is realized by solving it with the semigraphical method using a program code for graphing and a special code for solving linear programming problems in the MATLAB environment. The problem solution is analyzed, and the ways to improve the solution by reorganizing the mixture composition are suggested.
Earth sciences and subsoil use. 2020;43(1):88-95
88-95
Analysis of diamond drill bit operation in well drilling under complicated conditions
Resumo
The purpose of the study has been to analyze the operation of diamond drill bits of a PDC type (polycrystalline diamond cutters) in the regions with a complex geological section, and to develop recommendations on optimizing the drill bits. The PDC drill bits are originally designed for soft to medium-hard rocks, thus being ineffective for complex geological sections. As part of the research, the mechanics of the build-up formation on the drill bit cutter and its impact on the rock destruction have been studied. The influence of the pumped drilling mud volume and the pressure differential in the downhole motor on the mechanical drilling speed of the PDC bit has been analyzed. Proposals on improving the geometry and orientation of the tool cutters and optimizing the design of the cutting structure calibratation site and the bit blades have been given; measures on reducing the bottomhole vibrations of the bit during its operation have been suggested. As a result of the study, the mechanism of the build-up formation on the cutter’s working edge and its advance influence on the fracturing in the rock volumetric stratum has been determined. It has been found that the maximum feed of the drilling mud results in the complete absence of the build-up formation and a sharp increase in the mechanical speed of drilling. The study has shown the high performance of high-torque downhole screw motors and defined the optimum range of the pressure differential for the PDC drill bits as a function of the drilling mud flow rate. The authors have suggested the ways to reduce the vibration and stabilize the PDC drill bits by optimizing the structure and geometry of the tool’s cutters and blades, and by using hybrid cutters as auxiliary ones. The conclusion is that the optimization of the PDC drill bits enhances their operation performance under complicated geological-engineering conditions in Eastern Siberia and Yakutia.
Earth sciences and subsoil use. 2020;43(1):96-102
96-102
Post-repair testing of the walking excavators’ electrical machines
Resumo
Dragline excavators are the main means of mechanization in mining coal fields. The operational reliability and in-use performance of the overburden dragline excavators determine the mining enterprises’ capacity. The aim of the study is to increase the reliability of the excavators’ electromechanical equipment. The main research method is modeling of the electromagnetic processes taking place in the after-repair tests of the excavator’s electric machines. The study has shown that the failures of the mining equipment operating in the northern part of Russia are of both mechanical and electromechanical nature. The failures associated with electromechanical emergency conditions are more often caused by the failure of the direct-current electric machines of the excavators’ main drives. To ensure the high quality of the repair and reduce the risk of failure, all electrical machines must undergo appropriate post-repair tests including those under load. The existing loading methods involve mechanical aggregation of the electric machine with the load devices. It is difficult to implement these methods when testing large direct-current electric machines in the conditions of the repair plants. Obviously, the development of the test methods that exclude mechanical aggregation of the electric machines and load devices is important and promising. Static loading of electrical machines is proposed as one of the above methods. The method implies dividing the test in two stages. In the first stage, static current loading is performed, and in the second stage, dynamic current and mechanical loading are carried out in the modes close to operational ones. The study of the control system developed for the electric drive of the test stand has shown that the system is functional and allows the testing of the direct-current electric machines in full.
Earth sciences and subsoil use. 2020;43(1):103-110
103-110
The use of a tactile sensory system in connecting counter workings
Resumo
At present, the problem of advancing mine workings when connecting them is that after advancing, the workings often coincide within the project workings’ contours, which causes a significant increase of the costs, diminishes the safety and creates ecological issues. The instrumental methods cannot provide quality determination of the workings advance direction when connecting the workings, thus the work safety deteriorates, and the cost of eliminating the consequences of the non-quality connection increases. To improve the ways of connecting the workings, either the existing technology should be modified or a new technology is needed. The purpose of the study is to develop a new technology for determining the direction of the counter workings when connecting the workings. The technology involves a tactile sensory system of man and is realized by the comparison of the degree of the rock surface vibration effect on a human palm at different points of the face. The vibration is created by drilling a blast-hole, and it is measured by applying the palm to the face. The suggested technology can enhance the advance exactness and safety, as well as increase the mineral output and reduce the costs of advancing the counter mine workings due to the decrease in the deviation from the target direction when connecting the workings. The technology can be used when advancing counter mine workings and connecting the workings in ore and alluvial mines.
Earth sciences and subsoil use. 2020;43(1):111-120
111-120
Results of Field Studies
Comparative analysis of Cenozoic volcanism in the East China block and Tunkinsky rift zone of the Baikal rift system
Resumo
A few volcanic structures have been investigated during the practical training programs in the area of Arshan (Irkutsk Region, Russia) and Nanjing (East China). The purpose of the study has been to collect the field material and perform a comparative analysis of the causes of the volcanic structure formation in the study areas. The volcanic activity has been characterized in geological and tectonic terms, and causal relationships between its intensification and structural confinedness have been defined. The research methods include field studies, as well as the analysis of literary and archive materials. The main achievement of the research is the determination of the global cause that influenced the volcanism of the territories. According to the authors, the commonality of the characteristics is to a large extent due to the consequences of the India-Eurasia collision.
Earth sciences and subsoil use. 2020;43(1):121-131
121-131