Home – Home – Jornals – Journal of Mining Sciences 2018 number 4

The system of integrated multi-level geomonitoring is developed for man-man objects and oil/gas reservoirs in the west of Russian Arctic. The system is based on the principle of synchronization of inter-branch researches, including geodetic, geomechanical, geophysical and geotechnical measurements on the ground surface and by GPS, as well as subsurface, surface, aerial and GPR survey. The system uses the information technologies Big Data and Cloud Service with intelligence elements, and provides monitoring investigations at differ levels: remote, air, surface, subsurface, computer. In-situ inter-branch multi-level studies are the framework of the geomonitoring which continuously replenish and updates data bases. The multi-level approach is also involved in computer modeling: the geodynamic models of a man-made object, Kola Peninsula, Baltic Shield and Eurasian Plate are created as hierarchically nested structures. The models are analyzed under various boundary conditions, which enabled solution of an inverse problem on stress state of subsurface rock mass differentially by the investigates scales. The multi-level geomonitoring system is implemented at man-made objects of the key mining companies of the Kola Peninsula: Kovdorsky GOK, Kola MMC, Apatit, Oleniy Ruchey and OLKON GOKs.

The nonlinear model is developed to describe geomechanical and hydrodynamic fields in the vicinity of a vertical well in a fluid-saturated formation for the case when the permeability k depends on the actual stress s_f by the exponential law. The analytical solutions are obtained for the porous-elastic and porous-elastoplastic modes of deformation of the well vicinity, based on which the change in the pressure and rate of flow under the variation of parameters characterizing the dependence k(s_f) is analyzed. It is found that the rate of flow exponentially decreases with an increasing horizontal stress of the external field; the permeability of the irreversible strain zone around the well decreases with the distance from the well boundary. The test scheme is proposed for permeability of specimens with the center hole under side loading, and the experimental data interpretation procedure is put forward, which enables finding the empirical dependence k(s_f).

On January 25, 2018 within the limits of the Vorkuta urban district, the regional seismic stations recorded an event classified as a rock burst. The records of 17 stations at the epicentral distances from 260 to 1645 km were collected and analyzed. The epicenter was localized in the Komsomolskaya Mine field of the Vorkuta coal deposit. Parameters of this event hypocenter were calculated by the data of the mine seismic monitoring network GITS, Vorkutaugo, which greatly improved reliability of determination of the hypocenter as compare with processing results of he regional stations and offered a reference estimate of the localization. January 25 rock burst has one more time proved that the geodynamic control and safety enhancement in the important mining region in the Republic of Komi requires installation of seismic stations nearby mine fields in the Vorkuta district.

The ground surface subsidence under mining at the Sokolov-Sarbai iron ore deposit is measured using radar survey data obtained over the period from 2006 to 2016. The purpose of the research is to determine features of the process inside the subsidence trough at Sokolovskaya Mine under conditions of water-encroached loose formations. Using a series of Alos Palsar and Alos2 satellite radar images, the vertical subsidence in the test area of the deposit is evaluated. The history and boundaries of displacements within the subsidence trough, in pitwalls and in dump slopes are determined.

The influence of underground excavations arranged nearby faults on the initiation of large seismic event is considered. Numerical modeling proves that amount of underground openings affects actual stiffness of rocks and initiates dynamic movements accompanied by intensive seismic radiation. As the rock mass quality worsens, the effective shear modulus drops. The calculations show that the effective shear modulus lowers by 20% for the stope on the same horizon, decreases 1.5 times in case of the stopes arranged on two horizons and nearly halves for three horizons. Such reduction in the actual shear stiffness of rock mass may be critical in terms of initiation of dynamic shift along a fault.

The methods for the determination of stress state in rock mass using the energy of explosion are validated. The commercial-scale tests are performed with a view to sizing zones of squeezing and radial fracturing in mines of Priargunsky Mining and Chemical Works. It is found that the fracturing zone radius decreases and the squeezing zone diameter increases with the grater depth of mining operations. The theoretical formulas for calculating stresses depending on sizes of squeezing and fracturing zones, physical and mechanical properties of rocks and detonation characteristics of explosives are obtained. The validity of the formulas is proved in comparison with the method of stress measurement in parallel drill holes at the Antei deposit of Priargunsky MCW. The method of stress determination by blasting is suitable for operational application during heading in mines.

Surface miners are being increasingly used in opencast mines owing to their ability to excavate thin bands selectively. Even minor variations in intact rock and rock mass parameters can adversely affect the performance of surface miner in terms of production and pick consumption. Power utilization both by rotary motion of cutting drum and linear motion of surface miner has been taken into account for arriving at suitable cutting speed and depth of cut. Cutting speed of surface miner, cutting force developed by individual pick and number of active picks coming in contact with the rock in respect to depth of cut under varied tensile strength can be determined through these studies. This will help the end user to decide suitable parameters for operational control. It is essential to optimize the operating parameters of machine (cutting speed and depth of cut) for a given rock mass condition with available machine power. The present study covers the 2.2 m wide drums of surface miner. Distribution of power available to the components of the machine has been arrived based on technical specifications of each component, taking power loss due to sleep occurs in belt power transmission mechanism.

The technical approach to selection and substantiation of transport systems for hard-to-access mineral mining in the Arctic is based on complexing of methods of computer-aided modeling and technical-and-economic assessment. The features of the transport system design for mountainous and upland-and-flat terrains are described. The obtained relations of transportation cost and volume make it possible to validate the choice of transport. In terms of the Partomchorr deposit, it is shown that under conditions of upland-and-flat terrain and minor level difference, it is efficient to use motor vehicles in case of small transportation volume (to 2.4 Mt/yr) and cable-and-belt conveying in case of large volume of transportation. For the Chinglusuai deposit situated in the upland country with large level difference, efficiency of cable-railway haulage with feasibility of energy recovery is substantiated.

The technical and economic feasibility of increasing the length of longwall 5003 in Yalevsky Mine to 400 m and raising output per face to 70 thou t per day in mining thick coal seam is substantiated. It is found that from the condition of maximum annual profit of the mine, the optimal longwall length is 450 m, and the variants of the longwall lengths of 400 and 512 m are equivalent. The methane release calculations show that at the indicated length and production output of the longwall, it is predicted that methane concentration in return ventilation air is 0.53%, which means no gas criterion constraints.

In addition to capacity increase, quality also has critical importance in the cement industry. In a cement product process, the chemical properties based on the oxide composition are necessary in describing clinker characteristics. One of the most important parameters in cement product, Lime Saturation Factor (LSF) controls the ratio of alite to belite in the clinker and this factor is frequently used to evaluate the quality of cement. This study focuses on identifying LSF distribution in the site conditions. For this purpose, probabilistic (geostatistical) and non-probabilistic (neural network-based) algorithms have been used. 3-D based analyses revealed some relationships in the site conditions. The accuracy studies performed by performance indicators specified that the non-probabilistic methods produced better statistical prediction capacity. Thus, the adaptive neural algorithms can ensure the results identify the quality distribution in connection with geological parameters.

Theoretical aspects of studying stability of natural systems depending on investigation purposes are briefly analyzed. Applicability of the watershed/landscape concept of nature management to study transformation of geosystems disturbed by gold placer mining is substantiated. In terms of a model site within the limits of the Ket-Kap cluster of placers, the data on the degree of such transformations are given, and mid- and large-scale landscape mapping is performed using the modern remote sensing techniques. The qualitative indicators of transformation degree under placer mining are given for valley nature systems depending on watershed order. The relevance of the remote sensing in estimating the degree of transformation of natural systems at objects of gold placer mining at regional and local levels is demonstrated.

Potential ranges of use of draglines at steeply-dipping diamond deposits in Yakutia are discussed. Technology of stripping with direct dumping and rehandling by draglines is substantiated for upper overburden layers. A variant of increasing height of stripping benches on haulage horizons through the use of draglines and crane lines. The resource saving technology is proposed for mining roundish and extended ore bodies with alternating advance of mining front and with internal dumping. The method of estimating efficient thickness of overburden in case of direct dumping is developed using the layer coefficient of overburden rehandling. Expediency of using blasting for displacement of broken overburden to internal dump is specified.

The data of the full-scale experiment on adjustment of VOMD-24 fan rotor speed with a view to controlling the fan efficiency under impact of the piston effect are presented. The reduction in actual air flow rate at the passenger platform of subway due to decreased fan efficiency is estimated at different intensity of traffic along the subway line. The algorithm of the tunnel fan rpm adjustment per day in conformity with the train traffic density and the architecture of automated control of the tunnel fan efficiency by frequency transducer are proposed.

The mechanism of weakening and directional change in structural and chemical properties of eudialyte under nonthermal exposure to nanosecond high-voltage electromagnetic pulses and nitric-acid leaching is studied. The methods of X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy and microhardness measurement are used. The rational mode of high-energy pulsed treatment is determined. After such mode treatment, the acid leaching of eudialyte concentrate results in recovery of zirconium and total rare earth elements higher by 1.7 and 1.4 times as against reference standards.

Mineralogical composition, structural changes and floatability of minerals in the content of the Novosibirsk Tin Works waste are examined. It is shown that casserite is totally unfloatable after long stay in tailings pond, while iron sulfides preserve flotation ability despite the fact that their structure is partly X-ray amorphous. Combining key beneficiation techniques allows production of concentrates with the tin content of 10% and higher, though the tin recovery is no more than 17.2% in this case, which prevents from recommending the combination dressing for application. In the article, the flotation circuit producing tin concentrate at the yield of 5% and recovery of 80%, which meets the requirements of fuming process and electric melting, is proposed and substantiated.

The research findings on floatability of old gold-bearing tailings are presented. The complex material constitution and process features of processing waste are governed by difference in treatment of various ore types (sulfide, oxidized and mixed) at processing plant, as well as with supergene processes in the tailings pond. Feasibility of re-flotation of tailings is discussed. it is found that short-term mechanical activation of tailings in a mill with the subsequent flotation (at the adjusted reagent mode as against the current technology) results in gold recovery of 29.0 to 45.4% in flotation concentrate at the residue content of metal in rejects at the level of 0.2-0.3 g/t.

Based on the studies of compositions of dispersed ions in sewage water after mining and processing of niobium ore at the Lovozero deposit, it is substantiated to be expedient to convert some pollution agents from solution to suspension state. A combined process is proposed for treatment of mine wastewater, which is 94% of total sewage water of mining and processing, by integrating coagulation, sorption and flotation techniques. The mathematical model of aggregation of suspension particles with regard to the hydrodynamic mode of coagulation is suggested. The model makes it possible to predict material and dispersion compositions of a new multi-phase system under different temperatures towards automation of the wastewater treatment process. The solution on forming surface properties of activated aqueous dispersions of air using a modified finely dispersed sorbent with intent to intensify the wastewater purification process.

The processes of rebellious ore disintegration with regard to the surface properties of minerals and rocks are discussed. The methods are proposed for the experimental determination of surface tension of solids during evaluation of dispergating efficiency, and the calculation procedure of the surface layer thickness during ore disintegration is offered. The calculations of the fusion temperatures of nanoparticles obtained in nonconventional disintegration of rebellious ore are presented. The calculations are performed for the nanoparticles with possible content of the most metals from the periodic chart.

Environmental impact of mining is studied by two criteria: aerosol pollution and vegetation cover condition-using the data of long-term satellite observations. In terms of the mining and processing industry on the Kola Peninsula, environmental impact is predicted as overlapping of aerosol pollution areas and decrease in the vegetation index. It is shown that predicted boundaries of impact-zones match in case of one or two sources of effect, and unmatch in case of many sources. The proposed approach to integration of the remote sensing data allows differentiating between the environmental impact of mining and natural change of the vegetation cover.

Particulate pollution is very abigissue in coal mining area. The particulate matter affects human as well as nearby animals, vegetation and degrade the ecological environment in many ways. So every time it is fetching the attention of researchers to find work on the issue. Talcher coal field, one of the oldest coalfields of India with a very high coal deposit. A monitoring of respirable dust (PM₁₀& PM_2.5) has been performed at eight monitoring stations around a high mechanised opencast coalmine for two seasons i.e., summer and winter. Samples were collected as per the standard criteria of central pollution control board (CPCB), India. Winter season was found to have more particulate concentration as compare to summer. A total of 10 trace elements were analysed and selected for source apportionment of particulate matter and associated heavy metal. Statistical analysis such as univariate (correlation study) and multi variate statistical analysis were used including principal component analysis (PCA) for source identification and respective contribution to particulate matter. The major sources of trace metals were mainly coal mining and associated activities, vehicular emission etc.