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Journal of Mining Sciences

2013 year, number 2

1.
FROM THE ALTERNATING-SIGN EXPLOSION RESPONSE OF ROCKS TO THE PENDULUM WAVES IN STRESSED GEOMEDIA. PART II

V. V. Adushkin1, V. N. Oparin2,3
1Institute of Geosphere Dynamics, Russian Academy of Sciences, Leninskii pr. 38, Moscow, 119334 Russia
2N.A. Chinakal Institute of Mining, Siberian Branch, Russian Academy of Sciences, Krasnyi pr. 54, Novosibirsk, 630091 Russia
3Novosibirsk Sate University, ul. Pirogova 2, Novosibirsk, 630090 Russia
Keywords: Rock mass, block-hierarchical structure, nonlinear geomechanical processes, instrumentation, earthquakes, rockbursts, blasts, underground excavations, open pit walls, pendulum waves, seismic events, geomechanical-geodynamical safety system

Abstract >>
The article reviews research and development results in the sphere of designing unique apparatuses and equipment for modeling and in situ recording of nonlinear elastic waves and associated electro-magnetic emission in stressed block-hierarchical rock masses. The joint experimental outcomes and theoretical research findings gained by leading institutions of the Russian Academy of Sciences and its branches within recent decades in the framework of integration inter-disciplinary projects offer a methodology and instrumentation support for new promising systems of integrated geomechanical and geophysical monitoring of mining-induced earthquakes and rockbursts in Russian mines used as unique natural laboratories for both academic and applied research in the domain of geosciences.



2.
ZONAL DISINTEGRATION MECHANISM OF THE MICROCRACK-WEAKENED SURROUNDING ROCK MASS IN DEEP CIRCULAR TUNNELS

X. Zhou1,2, Q. Qiana1,3,4
1School of Civil Engineering, Chongqing University, Chongqing, 400045 China
2Key Laboratory of New Technology for Construction of Cities in Mountain Area, Chongqing University, Ministry of Education of China, Chongqing, 400045 PR China
3Engineering Institute of Engineering Crops, PLA University of Science and Technology, Nanjing, 210007 China
4State Key Laboratory of Disaster Prevention & Mitigation of Explosion & Impact, PLA University of Science and Technology, Nanjing, 210007 China
Keywords: Underground tunnel, zonal disintegration, non-Euclidean model, damage variable

Abstract >>
Rock masses without pre-existing macrocracks are considered as granular materials with only microcracks. During excavation of tunnels, microcracks may nucleate, grow and propagate through rock matrix; secondary microcracks may appear, and discontinuous and incompatible deformation of rock masses may occur. The classical continuum elastoplastic theory is not suitable for analyzing discontinuous and incompatible deformation of rock masses any more. In this paper, a new non-Euclidean model is established to investigate zonal disintegration mechanism of the surrounding rock masses around a deep circular tunnel. Effect of damage variable on the zonal disintegration under non-hydrostatic stress condition is taken into account. Based on non-Euclidean model of the discontinuous and incompatible deformation of rock mass, the effect of the half length and density of microcracks on distribution of stresses in the surrounding rock masses around a deep circular tunnel is investigated. The stress concentration at the tips of microcracks located in vicinity of stress wave crest is comparatively large, which may lead to the unstable growth and coalescence of secondary microcracks, and consequently the occurrence of fractured zones. On the other hand, the stress concentration at the tips of microcracks located around stress wave trough is relatively small, which may lead to arrest of microcracks, and thus the non-fractured zones. The alternative appearance of stress wave crest and stress trough thus may induce the alternative occurrence of fractured and non-fractured zones in deep rock masses.



3.
A CONTINUUM GRAIN-INTERFACE-MATRIX MODEL FOR SLABBING AND ZONAL DISINTEGRATION OF THE CIRCULAR TUNNEL SURROUNDING ROCK

X. Wang, Y. Pan, X. Wu
College of Mechanics and Engineering, Liaoning Technical University, Fuxin, 123000 P. R. China
panyish_cn@sina.com
Keywords: Zonal disintegration, slabbing, self-organization, shear band, tunnel, grain, interface, matrix, dominant microstructures

Abstract >>
It is difficult to numerically reproduce the common failure modes of the circular tunnel surrounding rocks, such as the slabbing or delamination in hard rock, and the zonal disintegration at great depth, based on continuum and homogeneous elastoplastic models. In the present paper, a grain-interface-matrix model is proposed based on continuum elastoplastic theories, and implemented in FLAC. Rock is simplified as a compound of the circular grains, rectangular interfaces, and remaining matrix. These components are modeled by squared elements with the same size. Results show that shear strains exhibit intersecting and multiple shear bands or slip lines extending intergranularly. High principal stresses in compression are found to form rings around the tunnel surface. For fine grains, the intensive rings are found, similar to the slabbing; while for coarse grains, the spacing between rings becomes large, analogous to the zonal disintegration. Thus, a unified mechanism of two kinds of phenomena is explained as the self-organization process of dominant microstructures subjected to forces. Nevertheless, the scale of dominant microstructures regarding or governing the process is different. For hard rock without joints, the scale corresponds to actual grains; while for jointed rock mass under high compressive stresses at great depth, the scale of rock blocks is dominant.



4.
ANOMALOUS P-WAVE AND S-WAVE VELOCITIES IN A BLOCKY NATURAL SANDSTONE SPECIMEN

E. I. Mashinsky, G. V. Egorov
A.A. Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch, Russian Academy of Sciences, pr. Koptyuga 3, Novosibirsk, 630090 Russia
Mashinskii.EI@ipgg.sbras.ru
Keywords: Micro-nonuniform blocky media, inelasticity, nonlinearity, velocities of P-waves and S-waves, jointing, geostatic pressure

Abstract >>
The article studies velocities of P-waves and S-waves in a natural sandstone specimen exposed to axial thrust. The cylindrical core specimen 1 m long and 0.08 m in diameter is composed of different size blocks. Anomalous velocities of the P-waves and S-waves (4–6 kHz) have been revealed by measurements in the whole specimen, in it separate blocks and at contacts surfaces between the blocks. The velocities in the whole specimen are much smaller than in its separate blocks. The interblock contacts detain and decelerate the waves. With smaller spacing at the contacts between the blocks, the wave velocities linearly drop to anomalously low vales (hundreds m/s). With higher pressure on the specimen, the wave velocities nonlinearly grow and time delay reduces. The curve VP / VS P has a peak (1 MPa) that appears for separate blocks and for the whole specimen. The anomalous velocities VP and VS are alleged to appear due to inelastic processes at microcontact surfaces under acoustic wave propagation in the blocky medium.



5.
THEORETICAL GROUND FOR ORIGINATION OF NORMAL HORIZONTAL STRESSES IN ROCK MASSES

L. M. Vasilev, D. L. Vasilev
N.S. Polyakov Institute of Geotechnical Mechanics, National Academy of Sciences of Ukraine, ul. Simferopolskaya 2-a, Dnepropetrovsk, 490005 Ukraine
vdl_2007@mail.ru
Keywords: Normal horizontal stresses, ground pressure, rocks, shear resistance, contact friction coefficient, internal friction coefficient

Abstract >>
The authors show that normal horizontal stresses, either tensile or compressive, including exceeding vertical stresses, are initiated by contact friction between rock mass layers.



6.
CIRCULATION SYSTEM OF A PNEUMATIC DRILL WITH CENTRAL LIGHT SOLIDS REMOVAL

A. A. Lipin, Yu. P. Kharlamov, V. V. Timonin
N.A. Chinakal Institute of Mining, Siberian Branch, Russian Academy of Sciences, Krasny pr. 54, Novosibirsk, 630091 Russia
Keywords: Drilling tool, ring pneumatic drill, reverse circulation, cleaning agent, circulation system, downhole packer, air curtain

Abstract >>
The article describes experimental testing of a pneumatic drill tool with reverse circulation of cleaning agent. The authors assessed rational clearance between downhole packer and drill hole walls and propose an engineering design aimed for higher performance of the pneumatic drill circulation system.



7.
OPTIMIZATION OF THE FULLY-MECHANIZED STOPING FACE LENGTH AND EFFICIENCY IN A COAL MINE

A. A. Ordin, A. A. Metelkov
N.A. Chinakal Institute of Mining, Siberian Branch, Russian Academy of Sciences, Krasny pr. 54, Novosibirsk, 630091 Russia
ordin@misd.nsc.ru
Keywords: Optimization, profit, length and efficiency of the fully-mechanized stoping face, mine

Abstract >>
The authors formulate a problem and present analytical solutions on optimizing length of a fully-mechanized stoping face based on the maximum profit criterion.



8.
GEOMECHANICAL ASSESSMENT OF ORE DRAWPOINT STABILITY IN MINING WITH CAVING

S. A. Neverov, A. A. Neverov
N.A. Chinakal Institute of Mining, Siberian Branch, Russian Academy of Sciences, Krasny pr. 54, Novosibirsk, 630091 Russia
Keywords: Rock mass, face ore discharge, combined face-throughout ore drawing, depth, stress state, stability

Abstract >>
The authors solve the problem on stress–strain state of adjacent rocks of ore passes arranged in the face area under caved ore and the ore passes arranged both lengthwise the stope and in the stope face area (the face ore drawing scheme and the combined face-throughout ore drawing scheme, respectively) using the finite element method. The article describes stress distribution in higher stress zones and in distressed areas depending on the ore discharge preparation techniques at depths down to 1.5 km.



9.
COMPLICATED STRUCTURE GOLD PLACER MINING IN YAKUTIA

S. A. Ermakov, A. M. Burakov
N.V. Chersky Institute of Mining of the North, Siberian Branch, Russian Academy of Sciences, pr. Lenina 43, Yakutsk, 677980 Russia
s.a.ermakov@igds.ysn.ru
Keywords: Placer, nonuniformity, clay content, quality of reserves, processing, mining situation modeling

Abstract >>
A gold placer in the valley of the River Bolshoi Kurunakh occurs in complicated geological and mining conditions and is characterized by a highly nonuniform quality of the reserves. Modeling showed that the reserves occur in clusters distributed all over the productive sand extension. High clay content and liberal share of fine gold impede processing and reduce the output. The article offers a combined processing technology for the given placer, based on pre-concentrating of commercial mineral, and designates further research.



10.
TEMPERATURE EFFECT ON STRIPPING PERFORMANCE IN PERMAFROST ZONE

S. V. Panishev, S. A. Ermakov
N.V. Chersky Institute of Mining of the North, Siberian Branch, Russian Academy of Sciences, pr. Lenina 43, Yakutsk, 677980 Russia
s.v.panishev@igds.ysn.ru
Keywords: Permafrost rocks, adfreezing, overburden temperature, average fragment size, dragline, capacity

Abstract >>
In terms of Kangalassky Open Pit Mine, the authors discuss in situ monitoring of temperature on the surface of blasted overburden rock mass in the course of gradual dragline operation. It is shown that dragline capacity can be related with the surface layer temperature and average size of the blasted overburden fragment.



11.
MECHANICAL DESTRUCTION OF FLOCCULES BY SHEARING

V. E. Vigdergauz, G. Yu. Golberg
Institute of Comprehensive Exploitation of Mineral Resources, Russian Academy of Sciences, Kryukovskii tupik 4, Moscow, 111020 Russia
vigderg@mail.ru
Keywords: Flocculating structures, ultimate shear stress, rheology, pseudo-plasticity

Abstract >>
Based on the analysis of ultimate stress of floccules under shear, the authors determined maximum force and stress for bridges between particles of solid to keep strong. The rheological research showed that flocculating structures in concentrate suspensions and in coal flotation slurries are kindred with liquid-like pseudo-plastic systems by nature of flow. The experimentally obtained ultimate dynamic shear stresses depending on dosing of flocculants are comparable with theoretical calculations and distinct from the latter by 25% at the most.



12.
TRIBOCHEMICAL TREATMENT OF FELDSPATHICQUARTZ ORE IN FROTH SEPARATION

T. S. Yusupov1, E. A. Kirillova1, M. P. Lebedev2
1Institute of Geology and Mineralogy, Siberian Branch, Russian Academy of Sciences, pr. Koptyuga 3, Novosibirsk, 630090 Russia
yusupov@igm.nsc.ru
2V.P. Larionov Institute of Physico-Technical Problems of the North, Siberian Branch, Russian Academy of Sciences, ul. Oktyabrskaya 1, Yakutsk, 677981 Russia
m.p.lebedev@prez.ysn.ru
Keywords: Tribochemical treatment, electronic structure, quartz, feldspar, flotation, beneficiation, minerals

Abstract >>
Principles of tribochemical treatment of minerals have been developed to control the mineral flotation ability. It is found that floatability of quartz depends on the quartz electronic structure. Using feldspathic-quartz ore as an example, the author illustrate the improvement in separability of the minerals and ecological friendliness of the tribochemical treatment.



13.
EFFECT OF ACCUMULATED ENERGY AMOUNT ON STRUCTURAL CHANGES IN RARE METAL MINERALS UNDER MECHANICAL ACTIVATION OF CONCENTRATES

E. V. Bogatyreva, A. G. Ermilov
National University of Science and Technology MISIS, Leninskii pr. 4, Moscow, 119049 Russia
Helen_Bogatureva@mail.ru
Keywords: Mechanical activation, X-ray crystal analysis, wolframite, loparite, scheelite

Abstract >>
The authors discuss the probe-tested method of estimating amounts of accumulated energy in mechanical activation of wolframite, loparite and scheelite concentrates using X-ray crystal analysis data. The article proposes relations to calculate changes in energy amounts accumulated in phases of rare metal concentrates under dry and wet mechanical activation.



14.
ENTROPY OF TWO-PHASE FLOWS IN SEPARATION

E. M. Barsky
The Jerusalem College of Engineering, POB 3566, Jerusalem, 91035 Israel
eugene@jce.ac.il
Keywords: Separation, invariance, entropy, flow velocity, mineral beneficiation, mathematic model

Abstract >>
The new-developed approach to analyzing two-phase flow in mineral separation and beneficiation is based on the physical analogy of the flows and the perfect gas kinetic theory. The analysis from these viewpoints allowed formulation and basis of the invariants of such flows, where the key invariant is entropy of the two-phase flow, and its derivatives are potential extraction, chaotization factor and flowability. The mathematical modeling of the two-phase flow from the new points of view permits analyzing the flow using statistical mechanics techniques.



15.
REASONING AND DEVELOPMENT OF LOSS REDUCTION METHODS IN PROCESSING GOLD-BEARING CLAYS IN THE KHABAROVSK TERRITORY

T. N. Aleksandrova, A. V. Aleksandrov, N. M. Litvinova, R. V. Bogomyakov
Institute of Mining, Far East Branch, Russian Academy of Sciences, ul. Turgeneva 51, Khabarovsk, 680000 Russia
adm@igd.khv.ru
Keywords: Gold-bearing placer deposits, preliminary reactant treatment, gravitation, sorption, agglomeration-flotation

Abstract >>
The article gives theoretical reasons and experimental results on gravitational and flotation concentration of fine gold from highly clayey geological alluvium deposits and placer mining wastes. It is proved that one of the promising ways to intensifying gravitational concentration techniques is the effectual preparation of the material for beneficiation. The authors show that flotation concentration of gold successfully contributes to gravitational concentration toward higher total output.



16.
EMERGENCY CONTROL OF TECHNOLOGICAL ENVIRONMENT AND ELECTRIC MACHINERY ACTIVITY IN COAL MINES

I. V. Breido, A. V. Sichkarenko, E. S. Kotov
Karaganda State Technical University, bulv. Mira 56, Karaganda 100027 Kazakhstan
Keywords: Pre-emergency, emergency and post-emergency control, technological environment, operating regimes, electric machinery, coal mine, data reading, processing and storage subsystems

Abstract >>
The authors propose the developed standards and design of pre-emergency, emergency and post-emergency control of technological environment and electric machinery activity. The electric machinery operation parameters to be controlled are explosion-proof electric machinery being energized or not, cable integrity and improper access to the machinery; the control objects are switchers and starters within a mine district.
The technological environment parameters to be controlled are gas content, including CH4, CO, CO2 and O2, variation in mine air pressure, light, sound, temperature, acceleration or dislocation of central control unit housing.
The article presents engineering solutions on subsystems of data reading, processing and storage.



17.
Information for authors