Home – Home – Jornals – Journal of Mining Sciences 2017 number 4

The article reports the results obtained in the trial of elements of the monitoring system for potentially hazardous areas at Korobkovo deposit of the Kursk Magnetic Anomaly. The system is based on the seismic and deformation measurements aimed to estimate and control shear stiffness of potentially hazardous faults. The fault shear stiffness is estimated through the analysis of parameters of seismic waves in the vicinity of a fault. The sources of seismic signals in the trial were explosions carried out at the neighbor surface and underground mines.

The authors study the influence of physicochemical parameters on methane adsorption capacity of coal and offer the analytical method for the methane adsorption capacity for three-phased condition of methane. It is found that in the depth interval to 300 m below surface, methane adsorption capacity measured in lab can exceed natural gas content of coal obtained from geological exploration data by 30%, and the change in the thermodynamic condition of coal-methane system brings irreversible physicochemical consequences in terms of the altered ratios of physical states of the main components. There is no linear connection between natural gas content of a coal bed and its methane adsorption capacity with respect to occurrence depth. The application of Big Data in treatment and interpretation of large data flows is described. The theoretical data predicted using the proposed method and the experimental data on methane content of Kuzbass coal agree.

In focus of the article is minimization of aftereffects of the large-scale accident connected with the flooding of Berezniki Potash Mine in the Perm Krai. The authors construct a synthesized geomechanical model of the flooded mine to show the mining conditions, the process of salt rock dissolution and the elastoplastic behavior of deformation and failure of undermined rock mass in time. Approaches to analyzing intensity of degeneration of load-bearing elements of the open stoping system as a consequence of salt rock dissolving are proposed. The obtained estimates are the parametric framework for prediction of the ground surface deformation using 3D mathematical modeling. The geomechanical calculation results are used in the managerial decision-making on safety of the industrial and civil infrastructure within the hazardous territory.

Gas-water relative permeability (GWP) is measured in the tests of full-diameter cores. Based on the obtained GWP curves, the standard normalized curves are plotted for three types of carbonate reservoirs: matrix pore, fracture and solution pore. The corresponding gas and water two-phase flow model was deduced by considering stress sensitivity and non-Darcy effect, and the IPR curve calculation and analysis of gas wells of the three types were carried out. Based on huge gap between the matrix and fracture permeability, the phenomenon of gas drive water mainly exists in the cracks. So the conventional gas-water relative permeability of fractured gas reservoirs was modified. The research will lay the foundation for the application of gas reservoir engineering calculation with the production and application of numerical simulation technology to make dynamic forecast.

The integrated study of coal is performed using methods of optical and electron paramagnetic resonances, infrared spectroscopy and Raman spectroscopy. It is found that gas content of coal is governed by the rank of coal and its material constitution as well as by the coal bed structure at the macro-, micro- and nano-levels which interwork. It is discovered that the size and amount of bubbles, of paleo-origin presumably, and the content of coalbed methane are related. The influence of each scale level of the coal bed structure on the gas content is revealed. The authors illustrate benefits of the integrated study of gas-bearing coal with the physical methods that complement one the other at different levels of coal structure.

The authors solve the problem on forces required to change drilling path of air hammers in soil. Soil mass is assumed a rigid-plastic medium with the Mohr-Coulomb yield, and the air hammer deviator is considered as a nondeformable body. The problem is solved in two stages: introduction of the deviator in soil and travel of the air hammer in soil with the rear deviated at a certain angle. The loads applied to the rear, the forces and the moment required to changing the path of an air hammer in soil are calculated.

The substantiated dimensionless criterion of jamming characterizes relationship between the temperature of the contact links of spiroid gearing and the load-bearing capacity of an oil film. Based on the review of the existing tribotechnical systems used in scoring resistance testing, a physical model of spiroid gearing is selected. The test data obtained on a rolling-and-disc scheme of a friction assembly are presented. The relations between the friction coefficient in the spiroid gearing and the unit load are determined for the steel-steel material couples in a range of slip velocities and temperatures. A design procedure for spiroid gearing with respect to jamming is proposed.

Under study is a production system composed of a power motor, compressor, pneumatic percussive machine and a treated medium. Based on the generalized theoretical and experimental data, the author relates productiveness of pneumatic percussive machines, energy intake of rock breakage in the uplands with the rare atmosphere and elevation of the machine work site above sea level. The obtained results offer a reason-why approach to selection of the pneumatic percussive machine parameters for operation in the uplands.

The authors describe a technical approach to validating efficient regimes and process flow charts for draglines in open pit mining in permafrost zone; the approach integrates modeling data on temperature conditions of permafrost treated by blasting, geometrical parameters of a dragline face and interaction of work cycle time and face rock temperature in different seasons. It is shown that a dragline has the appreciably reduced productivity in slice-by-slice handling of broken-rock disintegration having negative temperature.

The article presents a procedure to select loading and transportation machines for an open pit complex ore mine. The choice of a shovel-dump truck production system is validated using a statistical testing method (Monte Carlo technique). Stop-watch readings allowed relating the productivity of the production system, degree of ore fragmentation and content of oversizes; the soundness of the choice of the production system based on the revealed criterion was proved. Using the law of the Palm flows, the authors determine the number and sequence of dump trucks for loading in a one-server system.

The authors have studied the mechanism of the controlled modification of composition, structure, chemistry, physicochemical and process properties of columbite, tantalite, zircon and feldspar at the meso-, micro- and nanoscales after nonthermal treatment by high-voltage nanosecond electromagnetic pulses. The studies used the methods of X-ray photoelectron spectroscopy, scanning electron and atomic force microscopy, potentiometric titration, electromigration chromatography, Kelvin probe force microscopy, microhardness metering and assessment of hydrophobic behavior and flotation activity of the minerals. It is found that the change in the chemical state of atoms on the surface of the minerals is mainly connected with the sequential transformation of stages in the process of formation and modification of the functional cover of a mineral surface, with the variation in the ratio of different type hydroxyl groups on the surface of columbite, zircon and feldspar, which conditions contrast physicochemical properties of rare metal minerals and improves selectivity of their separation by flotation.

The authors analyze collecting capacity of desorbable species of xanthates. Desorbable species of a reagent are understood as the species capable to transfer from mineral particle to air bubble, i.e. to gas-liquid interface, at the moment of rupture of an interlayer between these interacting objects. Flotation process performance is evaluated at the presence of a mixed coating resulting from physical and chemical adsorption and in the presence of a chemosorption coating only. The rates of spreading products of interaction between butyl ethyl xanthates and lead nitrate over water surface are found. The spreading rates and collecting capacities of the mentioned reagents are correlated. It is found that an increase in the length of the hydrocarbon fragment increases collecting capacity of a reagent and the rate of spreading of its products over water surface.

In terms of sulfide copper-molybdenum ore of Sorsk stockwork deposit (Republic of Khakasia), the authors discuss the option of selective dissociation of minerals. The scope of the discussion embraces effect of pulsed-discharge treatment on particle-size indexes, structural and chemical properties and floatability of objects of the study. It is shown that the pulse-discharge treatment in a greater degree influences copper sulfides and levels their floatability while surface of molybdenite undergoes minor alteration. The pulse-discharge treatment allows enhancing flotation selectivity efficiency in separation of copper sulfides and molybdenite, and promotes removal of hydrophobic molybdenite film from quartz surface, which results in production of high-quality molybdenite concentrates.

Under analysis is on-site extractability of nonferrous and noble metals from tailings by leaching using natural reagents (humus acids, water, lignin). Redistribution of nonferrous and noble metals in percolation bed made of old tailings in the Norilsk copper-nickel ore field is studied. Kinetics of dissolving of nonferrous and noble metals under capillary ascensional percolation is investigated. It is shown that directional capillary percolation of solutions is applicable to extraction of nonferrous and noble metals from long-term storage mining waste.

When gold occurs in mining waste for a long time, it becomes coated with dense films of hydroxide of iron, manganese, copper and silver sulfides, hydromica powder and clayey particles, which greatly complicates concentration of such gold by gravity. An efficient method to remove such coatings from gold is treatment of waste using chemical reagents based on halogen-containing compounds. The article presents experimental results on extraction of fine gold from tailings of sluice boxes and dredging classifiers using such chemical reagents.

The undertaken research is aimed to reveal optimal physicochemical conditions for deep conversion of calcium-bearing alumosilicate raw material. An innovative technology of integrated extraction of nano-dispersion amorphous silica, alumina, calcium fluoride and other useful elements has been developed.

Under consideration is the influence of various crushing techniques on the particle-size distribution and selectivity of dissociation of basic mineral components in the composition of Dalnegorsk complex ore under pretreatment. Distribution of basic elements per size grades is determined in crushing feed and in products of magnetic separation and flotation. Conditions of preparation and separation of disintegration products are described. The authors illustrate the change in the dissociation selectivity criterion in jaw crushing and in disintegration in press to prepare different size ore for processing by magnetic separation and flotation.

In terms of Tashtagol Mine, the authors address the issues connected with the determination of surface shape in cavities formed by blasts of explosive charges in high-stress rock mass structured as a hierarchy of blocks. Laser scanning of a cavity offers the data on linear and angular characteristics of the cavity surface. The analysis of the surface structure provides details of the rock mass block hierarchy, which essentially influences formation of the roof and sidewalls of the cavity. Individual areas of the cavity surface are described with the help of approximation of measured coordinates of the cavity boundary in the cross sections using the second order curves, including circumferences and ellipses the radius of which are canonically connected with the phenomenon of zonal disintegration of rock mass.