Home – Home – Jornals – Journal of Mining Sciences 2016 number 1

The scope of this expert and analytical review encompasses major achievements in the area of nonlinear geomechanics, geophysics, geomonitoring and advanced information technologies with a view to developing the natural and induced emergency prevention and response technology listed among the “national critical technologies” in the Russian Federation. The topical trends of the related R&D activities are basic research in physics and geomechanics of natural and induced failure source formation and growth in rocks and in mines, and creation of multi-layer geoinformation monitoring system for geomechanical and geodynamic safety in Russia. The authors believe that the described R&D activities may be the basis for an international multidisciplinary mega-project in geosciences: Engineering and Creation of the World’s Multi-Layer Geomechanical, Geodynamic and Environmental Safety Geoinformation Monitoring System.

The authors discuss conditions for sinkholes at ground surface after the active phase of potash mine flooding has been completed. The mathematical modeling shows that interconnected signs of sinkholing are localization of subsidence in a comparatively small area, high gradients of subsidence at the boundaries of this area and occurrence of a solution cavity to accommodate the caved volume. The research findings are promising in terms of adequate space-time prediction of dynamic failure of strata above flooded mines.

The Murmansk Region in the northeastern Baltic Shield has been for long assumed as aseismic. Initiated in the 1950s, the regular instrumental seismological studies allow new data on the essential increment in seismicity, demonstrated in the maps of the general seismic zoning of the territory of Russia (OSR-97). Powerful mining industry in the Murmansk Region also induces many seismic events. This article analyzes natural and induced seismicity and their cross-effect.

An elastoplastic problem is considered for elliptical, arched, square and polygonal cross-section tunnels on the assumption of Coulomb’s limit equilibrium and varied lateral earth pressure coefficients in intact rock mass. The problem is solved using the method of small parameters and the finite element method. The elastoplastic solutions are obtained for mutually influencing tunnels. The mechanisms of concentration of vertical stresses in a pillar established between mutually influencing tunnels are determined.

The study is devoted to effect of contact friction on failure, ultimate stress and moduli of elasticity in rock specimens under compression. It is found that dependence of the listed characteristics on friction coefficient is incremental. The author reveals zones of full contact and slide.

Transformation of the molecular structure of coal under long-term effect of confining pressure due to strain relaxation is estimated numerically. It is found that both under dynamic deformation, as has been determined earlier, and under relaxation of molecular structure of coal, atoms of methyl group and hydrogen remove from aliphatic fringe, join together and form molecules of methane. It is shown that these molecules immediately form sorbing-based connection with coal. Volumes of methane absorption generated in coal due to strain relaxation of the molecular structure of coal are calculated.

The article reviews in brief application of cyclical-and-continuous method in the conveyor-and-truck haulage in open pit mines. Consumption of materials and power is evaluated as a function of mined rock haulage volumes and depth of crush-and-reload station position in an open pit mine. The change in capital and operational cost to transport ore and hard overburden is studied at varied distances from a crush-and-reload station in open pit to a surface receiving station. Efficiency of the conveyor-and-truck haulage using cyclical-and-continuous method is evaluated. In terms of deep and large mineral deposits, the authors substantiate positions for crush-and-reload stations in large open pit mines.

The article reports the results of estimation of internal dump slope stability in flooded open pit coal mine Tamnava-West Field. The geostatic analysis of stability used methods by Bishop and Morgenstern-Price. The studies confirm that slopes of internal dump are sufficiently stable and sustain stability after drainage of the open pit.

The authors describe experiments on pretreatment of ore by injection of explosive gases before underground leaching of gold in mine conditions. It is shown that injection of explosive gases into opening micro-fractures enhanced efficiency of underground leaching owing to microstructural transformation of ore containing dispersed gold.

The study is focused on the existing methods of long directional borehole drilling in hard rocks in high-viscous oil and natural bitumen field development. The authors suggest improving the hard rock mass drilling process by combining percussion-rotary drilling and positioning systems.

The article describes bench tests and calculations aimed to determining effect of parameters of ring-type elastic valve on variation of average pressure in the valve clearance. The results allow refinement of the design model of ring-type elastic valve and correction of the elastic ring cross-section based on the determined mechanisms.

The experience of engineering a small mobile compression-vacuum machine for seismic prospecting at shallow depths of 100-150 m is described. It is shown that percussion sources are preferable for shallow-depth seismic survey. The article reports laboratory and field testing data. The authors identify ways of further improvement of this class machines.

The determinants are found and the matrix is developed for rate of wear of heading machine cutting tool. Influence of rock strength on active life of heading machines is assessed. The authors describe field studies into the nature and rate of wear of cutters. The design of multiuse tangential revolving cutter of prolonged operating life is engineered and trialed. It is proposed to enhance rock cutting efficiency using a tool with a cutting wheel.

The key mechanisms of selective recovery of manganese ions from mine water by combination of chemical and electrochemical methods are studied. The authors present the efficient parameters of oxidation deposition of ions Mn²⁺ in electrolysis solutions of active chlorine forms generated in chloride-containing solutions under electric treatment and subsequent removal of dispersed phase manganese from the solutions. The mechanism of generation of dispersed phase manganese by electric treatment of acid mine water at copper-sulfide deposits is offered

The article presents studies of slime formation in processing of Vishnevogorsk columbium ore. The slime formation criterion is assumed as the presence of size grades less than 50 and 5 µm estimated from modern laser granulometer data. The optimal methods and equipment for grinding are chosen depending on rate of slime formation in final products. The studies use centrifugal and rod mills. The rod mill assures the lowest rate of slime formation. Based on the experimental results, the columbium ore pretreatment flowsheet and special ore disintegration methods have been selected. The flowsheet uses crushing machines ensuring the highest rate selectivity-inertia cone crusher and the lowest rate slime formation during milling-rod mill.

Water micro-emulsions of dibutyl xanthate as an active compound of commercial manufacture flotation agent are produced and analyzed using the methods of dynamic light scattering and zeta potential measurements. It is found that the typical hydrodynamic diameter of xanthate drops is of the order of 300 nm and their zeta potentials are negative. The effect exerted on properties of hydrophobic (pyrolytic graphite) and hydrophilic (silicon dioxide) surfaces by pretreatment with the micro-emulsions is examined using the atomic-force microscopy method and colloid probe (SiO₂ micro-sphere). The long-range high-amplitude attraction forces, probably of capillary nature, are revealed between the probe and surfaces after the contact with dixanthate for 1 min. It is supposed that these forces are conditioned by the action of gas nano-structures (nano-bubbles, nano-cavities, etc.) initiated on the surface rendered hydrophobic by dixanthate.

The industrial-level tests prove efficiency of Pseudomonas Japonica bacteria in production of copper-molybdenum bulk concentrate. Using scanning electron microscopy, it is found that adsorption of Pseudomonas Japonica bacteria takes place at the points of xanthate attachment. The infrared spectroscopy analysis shows that after treatment with the bacteria, C-O and C=S bonds vanish while valence and deformation vibrations in СН₃- and CH₂ groups become less intensive, which may be reflective of desorption of xanthate from the mineral surface.

In focus of the study are the results obtained in flotation testing of products of X-ray absorption separation that enhances 4-5 times WO₃ content of feed for the next flotation stage. The authors estimate feasibility of reducing yield of original ore screenings (non-gradable size) -6 +0 mm and its gravity concentration.