Search

Objective of the research is to develop annular-type drilling tools, which application increases mechanical velocity of drilling and overall productivity of drilling operations. Methodology is represented by the following: analysis and generalization of the scientific and technical achievements in mining industry; mathematical and physical modeling; and numerical methods of solution. Findings – a drill bit with following features has been developed: first, during the initial well sinking, the bit operates with one group of cutters; after their blunting, the worn hard-alloy cutting structure is replaced with the new sharp one, and well sinking continues without the tool lifting from the well. A multilayered drill bit has been developed with the equally loaded impregnated diamond-containing layers of comb profile, which using increases the bit durability and drilling productivity. Area of rational application of hard-alloy and diamond drill bits for core sampling during the exploratory drilling has been specified by means of comparative analysis of 1 m well cost drilled under the same mining and geological conditions using the mentioned tool. Originality – the operation of a drill bit with a telescopic cutting structure and a diamond bit with the equally loaded profile of diamond-containing comb-shape layers has been substantiated. It has been determined that the most prospective tendency meant for increasing durability of hard-alloy tools is in the development of a combined bit, which allows replacing the cutting structure, worn while drilling, with the new one without the drill string lifting onto the surface. Practical implications – drill tools (a bit with the telescopic cutting structure and diamond multilayered impregnated bit with the equally loaded profile of diamond-containing layers) are patented at the Patent Office of Kazakhstan. Use of the mentioned drill tools both increases productivity and reduces costs of drilling operations. Increase in the diamond tool durability is also provided by the creation of multilayered drill bits, which matrix height includes several impregnated diamond-containing layers of comb profile, divided by the diamondless layers of less hardness. [ABSTRACT FROM AUTHOR]

The aim of the study was to determine the Cu and Pb content in soil profiles in relation to main responsible factors in vertical distribution: type of soil, pH and mineralogical composition. Were exanimate 34 soil profiles from the industrial area of Craiova City. For each profile was collected bulk samples at different depths (40, 100, 150, 200 and 300 cm). The analytical techniques employed for the investigation of soil and rock samples were Atomic Absorption Spectrometry (AAS) for determination of heavy metals and X-ray Powder Diffraction (XRD) for determination of mineralogical composition of soil. The content data was compared with standards and levels registered by Romanian Legislation. Representative soils of this area, according to the Romanian Soil Taxonomic Classification are luvisols (preluvosol) and aluvisols (protisoil), they are formed on deposits consolidated of loess (Upper Pleistocene) and sand deposits, (Lower Holocene). The mineralogical data show that the main constituents of the solid mineral phase in the upper horizon of the soil area: quartz, albite, microcline, illite and montmorillonite, while in the lower horizon, besides the minerals mentioned above, the anorthite and the kaolinite are also identified. The statistical analysis of the pH values distributed by depth classes highlights the neutral to alkaline character of the analyzed soil solution. Concentrations of copper vary widely within and between each depth class. Is remarkable the copper concentration for a depth of 40 cm where the alert threshold is exceeded for 38% of samples. For 3.4 % of the analyzed samples is exceeding intervention threshold. The same trend is observed in the lead vertical distribution concentration. Copper and lead distribution was characterized by a significant surface buildup, followed by a decrease in concentrations with increasing depth, coming close to the background values. The layer of clay minerals present in the soil profile has an essential role in decreasing of Cu and Pb concentration with depth. Clay minerals adsorb Cu and Pb by binding the cations to interlayer positions of the clay particles. [ABSTRACT FROM AUTHOR]

The studies for Recent Crustal Movements by the aid of space geodesy techniques are integrated into the researches on the Earth’s crust dynamics, as a reflection of the complex geodynamic phenomena that occur in the crust and in the subcrustal lithosphere. In addition to the fundamental nature, the research in this field presents a practical characteristic, competing alongside geology and geophysics to the shaping of new energy sources or solid mineral substances, to the determination of the soil stability degree in inhabited areas or in those in which large industrial targets and utilities are intended to be placed in. The knowledge of movements affecting the Earth’s upper crust, movements that precede, accompany or follow the eathquakes, is also a topical issue. The paper presents some of the most important research projects developed in Romania, which were based on the measurement data obtained exclusively by space geodesy methods. There are presented some of the most significant results achieved in the framework of each research project together with the limitations imposed by the used acquisition technology. In chronological order are mentioned first GPS measurements in Romania, started in 1994, in a network centered on the Dealul Piscului observer, followed by Romania's involvement in a regional geodynamic project, CERGOP and finally a major international project, CRC461, also continued after 2003 with the continuous help of the University of Delft (Nederlands), a project that led to the development of an extended network of GPS permanent stations in Romania, all in operating status and whose results are a valuable support for the geodynamic studies. There are made brief references to the first application of the Finite Element Method in a GPS subnet from the Vrancea extended network together with some of the most important obtained results.The strong earthquakes with their catastrophic consequences, which have taken place in recent years on a global scale, similar to that of 4 March 1977 in Romania, have fully demonstrated the need for the knowledge of these types of crust movements in order to contribute, together with other methods, to solve the very complex problem of the earthquake forecasting. [ABSTRACT FROM AUTHOR]

The solving of European Commission (Research Fund for Coal and Steel) research project "Bucket wheel excavators operating under difficult mining conditions including unmineable inclusions and geological structures with excessive mining resistance" is under way from 2015 to 2018. The Brown Coal Research Institute j.s.c. is a member of the research team comprising Czech, Polish, Romanian and Greek technical universities and companies. The main task of the year 2016 was the realisation of the three long term measurements in the Libous Mine. The target of these measurements was verification of working parameters of the excavator SChRs 1550-4x30/K109 during the relocation from the first overburden cut to the second overburden cut with worse mining conditions. The paper briefly summarises the geological situation in these positions, results of a long term complex testing of the excavator and possibilities of overburden rocks mining in the new position. The relocation of the excavatot is possible according to the results of this research. [ABSTRACT FROM AUTHOR]

Ensuring the stability of the sides and ledges of deep open-pit mines is one of the main conditions for the safety of mining operations. To detect various deformations in both the array of permafrost and on the surface of berms and bench slopes along the edges of the open-pit mine, a ground-based laser scanner was used to monitor the local section of the southeastern edge of the Nyurbinsky open-pit mine. There are three conditionally most active temperature periods, influencing on the geocryological state of permafrost rock masses: May is the initial period of thawing of frozen rocks and soils, July is the period of their maximum thawing, October is the initial period of intensive freezing and swelling rocks and soils. On the investigated local section of the pit edge, by superimposing the results of three full-scale surveys with a laser scanner on a certain given time interval, an intuitive picture of the contours was obtained, along which a deformation occurrence on the surface of the local section of the pit edge slope - in the form of its bulging was revealed. The real parameters of the horizontal displacement of the slope line at certain sections of the pit edge were set and a 3D model of the southeastern edge of the Nyurbinsky open-pit mine was created. The obtained results of researches characterize dynamics of the shift of the open-pit edge. [ABSTRACT FROM AUTHOR]

The work given has been aimed at consideration of methodical approaches for the feasibility study of perspective in mineral deposits development, and based on it, preliminary ranking of criteria which should be applied relative to the Arctic solid mineral deposits. Authors used a formal logic method (analysis synthesis). It was revealed that both the domestic and foreign approaches cannot be applied directly for the feasibility studies of the Arctic solid mineral deposits because they consider the arctic conditions insufficiently, have weak infrastructure (including transport), isolated location and low energy consumption as well as economic-engineering and professional availability. Besides, there are no united methodical approaches for substantiating and parametric filling of criteria applied in feasibility studies of perspective in mineral deposits development with accounting different risks. Authors have offered methodical approaches for feasibility study of potential development of Arctic mineral deposits which are based on methods of investment projects efficiency assessment with accounting engineering-geological, technological, cost, and investment criteria and possible risks. [ABSTRACT FROM AUTHOR]

Conveyor belts operated on belt conveyors are subjected to a variety of loads that lead to damage. Belts undergo wear in a process that depends on the type of conveyor, its length, the material transported and the working site [2, 3, 5, 8]. Laboratory evaluation of a conveyor belt's lifetime requires determining a number of its properties, such as tensile strength, longitudinal and transverse elongation strength, delamination strength, shear strength, flammability, and resistance to low temperatures, as well as rubber cover tensile strength, abrasion resistance, aging resistance, etc. The methods for measuring the above mentioned properties, as well as the required limit values for the properties, are standardized. However, a group of belt properties has not yet been standardized, although they have a fundamental importance for belt lifetime. Tests performed for many years in operating conditions show that the majority of belts undergo wear and are disassembled from the conveyor as a result of damage caused by punctures and cuts [4, 8, 9, 10]. Therefore, an assumption may be made that the resistance of conveyor belts to punctures and longitudinal cuts are among the most important criteria for the evaluation of their lifetime, which in turn remains a key factor affecting the costs related to the operation of belt conveyors. According to analyses performed in mining plants, the share of the costs of conveyor transportation is estimated to be between 8% and 30% of the production cost, depending on the type of a mine. These costs include both the cost of electricity and the costs related to the wear and replacement of belt conveyor elements, especially of conveyor belts. The aim of this paper is to present the results of research into conveyor belts, which may be implemented in mining industry to lower the costs of operating a conveyor transportation system [11, 12]. [ABSTRACT FROM AUTHOR]

The article presents the results of asymmetrical disk tools laboratory tests. This type of mining tools can be used for mechanical mining of hard rocks, among others in the solution of innovative roadheader head, presented on SGEM conference in 2016. The study was conducted at a dedicated laboratory stand, with an installed drive power of 80 kW. Stand consists of rotating rock sample, mined by special plate equipped with asymmetrical disk tools. The rock is mined using undercutting technique, also known as Wohlemyer method, after the name of its Austrian researcher. During research six components of the load acting on the disc plate were measured; in addition to this, thermographic observations were conducted. Tools have been tested in both qualitative and quantitative ways. Qualitative research consisted of disc measurement using 3D scan both before and after the mining test. After comparison of the corresponding three-dimensional images of discs and performing measurements with the appropriate computer software, image of individual tools wear were obtained. The results of quantitative research were based on gravimetric measurements of disks before and after the tests. The findings from conducted research may help in selection of the optimal tool for mechanical hard rock mining using undercutting, as well as to make estimates of the sustainability of individual disc tools. [ABSTRACT FROM AUTHOR]

In accordance with the developed methodology for a comprehensive solution of issues of mineral deposits development in the Russian Arctic zone, a list of criteria has been established that allow evaluating the priority of nuclear power sources in solving problems of power supply to the Russian Arctic regions while developing the deposits and performing a ranking of the various reactor plants. The list is based on information technologies modeling objects, production and processing of raw material and geoecotechnologies and on requirements for small nuclear power plants. A single interactive map of the solid mineral deposits of the North-West of Russia had been designed in the GoogleEarth system. The map gives the opportunity to form an integrated multi-level system of dealing with the databases of the Russian mining complex, and is also a platform for the design of innovative technologies in the development of deposits. The Partomchorr apatite deposit was used as an example to attach to the map the digital models of ore bodies created in the MGIS MINEFRAME software with the calculation of reserves and the distribution of the content of useful components. The principal scheme has been substantiated to process the prospective Afrikinda perovskite ore, which is a source of raremetal and rare-earth raw materials based on the mineralogical and technological peculiarities of perovskite ore, and the revealed regularities in the distribution of minerals by the size classes. The technology includes magnetic separation to produce a titaniummagnetite concentrate, gravitational concentration of the non-magnetic fraction, separation of the dump tailings and rough perovskite concentrate, and the refining by the flotation method. The methodology for assessing the aerosol impact of mining enterprises on the natural environment by satellite and terrestrial data has been developed by the determination of the specific load and the area of impact, taking into account the vegetative index. The assessment of the aerosol impact of the Murmansk regional mining enterprises on the natural environment is in good agreement with the data of surface observations. The concept of improving the ecological state of the Arctic natural environment is substantiated by the restoration of disturbed objects on the basis of studying the level of mining-induced load, the regenerative capabilities of the natural environment with the aim of activating the processes of its self-restoration. [ABSTRACT FROM AUTHOR]

Salt mines areas are known to be very dynamic environments as a consequence of salt rock ability to expand, contract and even "flow" (plastically flow) in certain stress and pressure conditions. As the sodium chloride is a high demanded resource since ancient times, old salt mining works are documented to have been executed even in areas nowadays exploited. The lack of precise location of ancient mine entrances and abandoned underground fieldwork locations poses severe problems to current mining activity, as well for other types of land use. Sinkholes, landslides, induced seismicity and eruptions of pressured salt brines springs are among the most common geological hazards associated to salt mining activities. Geophysics is known to play an important role in rock mineral exploration due to the capability of geophysical methods to explore the specific structures of geological formations or the rocks petrophysical properties. The same techniques of investigation, adequately adapted to the site specific requirements and targets, can be used for hazard delineation in nowadays exploited or in old mine areas. For hazard assessment, several studies which implied the use of gravity and resistivity prospection methods have been executed in high risk zones of a salt mine. The studied mine area is a joint between ancient exploitation zones still undiscovered, already collapsed salt mines or recently exploited and abandoned ones, placed in active mining areas. The complex salt tectonics, the presence of land instability areas and lakes with salty water (formed after the collapse of old mines roof), the presence of platforms covered with thick concrete layers and the recent constructed industrial buildings, created a challenging environment for the geophysical prospection. Despite the field impediments, the employed geophysical methods proved to be very useful for hazard delineation in salt mine areas. Gravimetric maps revealed the cause of a building subsidence, the data processing allowing the characterization of the buried hazardous source. The resistivity geoelectrical measurements (VES and ERT) revealed old mine shafts, abandoned salt exploitation rooms displaying broken roofs, fractures affecting the entire salt deposit and neighboring geological formations. Through the use the mentioned geophysical methods it was possible to characterize this very unstable industrial area. [ABSTRACT FROM AUTHOR]

Self advancing support MEOS 26/56 is in in the operation of the Ostrava-Karvina collieries considerably extended. It has a number of advantages, such as relatively small weight and the price, compared with supports for lower price and weight in particular a considerable range of extent. The specific type of MEOS 26/56 has extent from 2.5 m up to 5,6 m. This is particularly advantageous in a thick seams a Karvina area of OKD, due to the fact that, in them is the variability of the thickness very considerable. The disadvantage of the support MEOS 26/56, but it is the fact that in a situation where it has to provide a higher thickness of seams the sliding bar has a higher distance from the edge of the pillar. By this emerge between the end of the sliding bar and the edge of the pillars the free unsecured space and this constitutes a considerable risk of uncontrolled fracture of rock which can induce caving in the ceiling. The subject of the work is presented an assessment how this hazard eliminated. [ABSTRACT FROM AUTHOR]

Estimation of blasted rock fragmentation is of great importance in hard rock mining. There are many, mostly empirical or semi-empirical, models for its estimation. New theoretical model for estimating fragmentation of blasted rock is proposed in this paper. Model is based on theoretical research in rock breakage by explosives. Conducted research resulted in new rock breakage theory that made possibility of estimating tension crack density and radii of fragmenting zones. Utilizing these theoretical results with assumption that prior blasting quasi-isometric fragments are formed it is explained how blasted rock fragmentation could be estimated. Also, it is shown how structural properties of rock mass impact rock blasting and its fragmentation. Example is given, at the end of the paper, where it is explained how rock fragmentation could be estimated using geometrical analysis. [ABSTRACT FROM AUTHOR]