Home – Home – Jornals – Journal of Mining Sciences 2015 number 1

The article reports the lab experimentation on seismic/acoustic emission during different mode inter-block movement in rock mass. The fact that co–seismic displacement under induced earthquakes occurs along the existing interfaces is the basis for relatively simple tests on a slider-model plant. Using different materials as fracture fillers allowed modeling entire range of probable deformation modes. The deformation modes are conditionally grouped as creep or steady–state sliding, unsteady-state sliding and regular discontinuous sliding or stick-slip. The authors show that statistics of acoustic emission during sliding is described using the Gutenberg–Richter law. The largest “representative” events under shearing occur quasi–regularly, with probability much higher than follows from the law of frequency. The functional relation is found between the acoustic emission energy and the shear velocity.

The authors have developed and manufactured a test bench and a measurement apparatus for modeling movement of surfaces of faults with a pre–loaded granular filler in rock mass under trigger destressing. The trigger is a weak seismic wave generated by a single point–wise blow. It is found that displacement discontinuities appear under drop of force. It is shown that soft loading consumes much energy and destressing in this case results in smaller drop of forces but larger displacements. The authors find out that displacements are initiated by the destressing wave that lowers contact friction in the geomedium.

The authors have developed the FEM geomechanical model to describe evolution of temperature and hydrodynamic fields at the tailings dam of the Kumtor Gold Mine, Kyrgyzstan, in the permafrost region. The influence exerted by the temperature variation in the liquid waste accumulated in tailings pond and by the changes of size of impervious screen on the volume of filtrate material through the dam is evaluated in numerical experiments. It is shown that the pressure variation rate in the monitoring hole can be the indicator of the impervious screen rupture.

Under analysis is the experimental testing of interaction between the limit of strength and the acoustic Q–factor in terms of Kasimov deposit limestone. The limit of strength is found using two procedures, namely, direct method and interpolation, which are compared. The authors illustrate the advantage of the acoustic Q–factor procedure in assessment of damage and residual strength of rocks as against the method of elastic wave velocities. The resultant relations can be used in assessment of residual strength and remaining life of pillars and roofs in underground excavations.

The study covers the issues of strength of rocks under three–dimensional stress, elastoplastic model with variable parameters of plastic flow, algorithm of problem solving with Stavrogin’s strength, evaluation of the numerical model correctness and the scope of use of the Coulomb criterion. The problem implementation uses Abaqus software. The calculated data on limit state zones around an underground excavation are compared with the strength conditions by Stavrogin and Coulomb.

The authors propose a physico–mathematical model to describe nonequilibrium filtration and diffusion of free and absorbed gas in coal in the framework of heterogeneous medium mechanics considering physical desorption. The model consists of a set of nonhomogeneous parabolic equations with a rigid source member. In terms of problems on propagation of compression and rarefaction waves, effect of the nonequilibrium desorption on the width of these waves is revealed. The problem on initiation and steady–state of a shock wave in coal is solved.

The authors have plotted the lines of energy flow in the problems on uniform vertical force applied at the boundary of an elastic half-plane and on indentation of a smooth pressing tool in a rigid-plastic medium. The influence of stresses on displacement velocities is analyzed. As an example, formation of compaction zone under ram block is studied.

The article presents the forecasting procedure for physico–mechanical properties of mine waste based on the data of geological and geophysical surveying, including electric resistivity tomography, in order to establish connection between physical properties of the material. In terms of a hydraulic fill at an open pit coal mine, the authors predict the change in the physico–mechanical properties of the hydraulic fill under a dump embankment.

The author describes physical simulation of natural stone block cutting using a plastic substance and specifies factors influencing energy input and quality of the cutting process. Recommendations on impact load application sequence, pattern of drill holes and sizes of cut stone blocks are given.

In focus is the current objective of energy efficiency improvement in mining in Russia and other countries of the world. The world tendencies toward new unconventional renewable energy sources and their introduction in closed–cycle resource–saving technologies are reviewed. In the capacity of the renewable energy sources, the authors discuss lithological pressure and elastic vibrations of rock mass, kinetic energy of gravity flow of backfill mixtures and fluids during backfilling and mine drainage, potential energy of gravity force of heavy trucks, energy of return air flows in mine ventilation and this energy recovery, etc. The authors think that conversion of these kinds of energy into electric energy during hard mineral mining will allow solution to ecological problems and enable development of allied branches in “small power engineering,” including essential reduction of external energy consumption in underground mines.

The discussion involves the issues relating rational development of natural noble metal placers and the placer mining waste, their resource potential and basic trends in mining, processing and beneficiation. It is found that the determinants of profitable development of a technogenic object (mine waste) is its pre–restructuring aimed at generation of a new structure and at increase in value of the reserves adapted to the chosen mining and processing technologies. The author substantiates the necessity and advisability of innovative technologies for placer mining waste development based on formation of concentration zones of commercial value components in dumps. The developed ways of technology modernization for gold washing machines enable increase in recovery of gold and other valuable associate components within a single work cycle.

The authors give brief information on Inaglinskaya mine planning within the Inaglinsky open pit mining lease in the South Yakutia Coal Basin and report the outcomes of technical–and–economic analysis of the mine construction and operation. The article presents formulation and solution of the problem on lag modeling and optimization of the mine design capacity.

The authors prove feasibility and efficiency of high–strength solid stone wire saw cutting in rock mass with subvertical and low–angle joints as well as drilling–and–wedge cutting of stone into marketable size blocks on the working site. The article presents and substantiates the procedure for rational selection of technology for high–strength stone preparation for cutting, considering geological conditions (shape of mineral body, orientation and spacing of joints), local temperature, as well as physico-mechanical properties and mineralogical composition of rocks.

The mathematical model is developed for describing temperature variation in soil body surrounding subway stations and tunnels, considering seasonal variation of air flow, soil freezing-thawing and induced heat flow from the subway. Using the finite element method, the authors calculate temperature field in soil body surrounding subway stations and tunnels at various depths under change in the atmospheric air temperature. Based on the numerical experiments, the thermal effect of shallow subway stations and tunnels on the surrounding soil body is estimated. The article offers the estimation procedure for delineation of influence zone of subway structures on temperature of surrounding soil. It is found that the zone of thermal effect of a subway structure grows with the depth of the subway structure occurrence. The dimension of the mentioned zone is conditioned by amount of heat produced in the underground structures of subway.

For recovery of iron oxides from disseminated iron ore, the flotation technology is developed based on using organophosphorus compounds as primary collectors. Selective preliminary removal of impurities and iron oxide flotation from wet magnetic separation tailings and directly from fine disseminated hematite ore ensures production of quality hematite-martite concentrates with the iron content of 64–66%. The option of by-production of gold from quartz present in hematite flotation tailings is illustrated.

The authors compare collecting activity of carboxylic acids and surface pressures of their film on water surface. It is found that these parameters correlate, and the surface pressure of the films depends on the length, saturation and branching of hydraulic radical and the availability of substituents. The problem on liquid removal from the film between air bubble and mineral particle is solved numerically. It is shown that the bulk force on the liquid in the film is conditioned by the surface pressure of molecules. The force of a flotation agent is defined as the force of the agent on the liquid in the film. The volumetric liquid flow from the film is related with the surface tension of agent forms active at the particle–bubble interface. The authors suggest the method of estimating collecting activity of physically attached agents by the value of force the agent exerts on liquid in the film.

The computer experiments on air bubble attachment and detachment with particles from 36 fractions of ore with different size and copper content display the influence of air bubble diameter and energy dissipation on the flotation selectivity. The concentration reached 80 at the optimized bubble diameter of 265 µm, which is 5-8 time higher than with the air bubble diameter of 1000-2000 µm standard for impeller flotation machines.

The authors generalize the research aimed at integrated production of nanomaterials. Mixes of metal ions are concentrated and separated in ion flotation. In micellar solutions of extracted ions, nanoparticles of metals or their oxides are obtained. Nanoparticles are converted in nanomaterials. The article discusses physico–technical problems of ion flotation, production of nanoparticles in direct micelles and properties of nanomaterials.

The author state feasibility of deep sulfidation of rebellious oxidized lead and zinc minerals under calcinations with pyrite concentrate in the aqueous vapor environment. It is shown that interaction between oxidized lead and zinc compounds and iron sulfide in the superheated vapor with sulfide formation takes place at the solid-gas interface, namely, MO–H₂S–under sulfidation of heterolyte and beudantite; PbSO₄–H₂S–under sulfidation of plumbojarosite.

The article offers the entropy method for detecting contamination clusters and anomalous high toxic substance content in water bodies of a mineral mining region in terms of Bunguro–Chumysh district in Kuzbass. Specificity of composition of various water kinds and their ingredients is identified, diagnostic signs of various contamination sources are revealed, integral characteristics obtained from combinations of water ingredients are ranked, and distribution of ingredients in various kind water relative to MAC value is analyzed.