Home – Home – Jornals – Journal of Mining Sciences 2014 number 4

The wave tomography method is a finite difference analog of the classical seismic ray tomography. The computational investigation is reported in the article. The proposed approach allows identification of velocity anomalies in jointed rock zones of methane accumulations if the sizes of these zones are comparable with the dominant wavelength of seismic sounding.

The authors discuss application of the modern concept on rock mass structure as a hierarchy of blocks and the phenomenological basis of the pendulum wave theory in the context of source areas of destructive events in natural and nature-and-production systems. The phenomenological relationship is set between Zhurkov’s concentration criterion of fracture, experimental criterion of underground excavation “collapse,” canonical structure of spectrum of pendulum waves by Oparin and the long-range action of heavy explosion impacts in geomedia by Sadovsky-Adushkin. The article validates the energy approach to describing transformation of elastic energy of destructive event source areas into kinetic energy of structural elements of these areas. The authors introduce a new notion of “interference seismic emission events.”

The theoretical basis and practical implementation of a complex loading device with instrumentation for mechanical properties of granular medium are described in the article. Thereupon, the procedure to determine the deviation from coaxiality of stress and strain tensors is developed. The authors report test data obtained on sand of various grain size. It has been found that rotation of strain tensor axes outruns rotation of stress tensor axes by an approximate angle of 21º.

In focus are methodology and effect of micro- and nano-indentation method in studying local deformation and failure of rocks. By micro- and nano-indentation, numerical values of Young’s modulus, and hardness of rocks and minerals have been obtained. The values of fracture toughness are obtained for separate minerals and at grain boundary. The authors highlight the use perspectiveness of the described method in estimating strength and deformation characteristics of rocks.

The authors suggest formulating limit state and failure criteria using the known and new stress tensor invariants. The new stress tensor invariants are constructed as average and shear stresses, as well as their ratios in all areas intersected by principal directions of stress tensor. The use of the obtained limit conditions is exemplified in terms of deriving equations of geomedium deformation based on the associated flow law.

The data on stress-strain state around an underground opening in an unstable rock mass are reported. For ground pressure relief, it is proved necessary to create a damping layer, and the related drilling-and-blasting parameters are determined. Zones of probable fracture of rock mass under camouflet blasting are identified.

The author has developed the model for determination of grain-size composition of fractured particles in a layer using the Bond crushing law. Furthermore, the model allows estimation of stress energy and grain-size composition of crushed particles in a layer under pressure.

In focus is the methodology of the support design for a tunnel in disseminated ore mining in the Zapolyarny Mine, Transpolar Division, Norilsk Nickel. The calculation of the rock bolting parameters in the affected zone of stoping is exemplified.

The article deals with aspects of effectivization of open pit coal mining by expanding the area of application of systems with draglining. It is emphasized that this most productive and least resource-hungry system lacks attention due to exhaustion of favourable conditions of its application. The authors make examples of draglining experience and potential effectivization.

The article formulates the problem on optimization of depth for transition from open pit to underground coal mining, considering lag factor. The main regularities are presented together with the numerical calculation of the set problem in terms of the Raspadsky Open Pit Mine using the dynamic programming method.

The robust control over open pit mining is validated. It is shown that the current coupling of production systems based on equality of averaged capacities of mining and transportation equipment ensures no operational stability in an open pit mine. The article presents an optimization model and the modeling procedure for scheduling equipment repair halts such that to gain sustainable productivity due to uniformly distributed capacity of operational shoveling and haulage equipment. The authors have set stability limits, which imparts robustness to a controlled system and moves management to a new level.

The authors discuss reduction of stripping in deep-level open pit mining by making the open bottom wedge-shaped. The article describes the calculation scheme and the correlation analysis of interaction between stripping amount and its determinants. The application constrains for the wedge-shaped open pit bottom are specified.

Under consideration is the creation and use of directional ionized airflows aimed at air purification and enrichment with light negatively charged ions in the production areas, which greatly reduces energy cost of ventilation and heating in cold weather. The article presents some data on use of ionized airflows in energy-saving technologies of the production area ventilation at mining and processing plants.

The morphology and spread of micro- and nano-formations on surface of apatite and shtaffelite ore minerals (apatite, shtaffelite and calcite) due to adsorption of fatty-acid collecting agents have been studied using the methods of optical, laser confocal scanning, analytical electron and atomic force microscopy. The Fourier-transform IR spectroscopy has shown that fatty-acid collecting agents are adsorbed on surface of apatite, shtaffelite and calcite in a mixed ion-molecule form; the ion form of attachment prevails for calcite.

It is hypothesized that the critical thickness of rupture of a liquid film between air bubble and mineral particle depends on potential and size of area occupied by nanobubble. It is shown that the critical thickness of the film equals the height of meniscus formed under rupture. The size and shape of meniscus are characterized by its neck radius and contact angle. The proposed hypothesis is based on the assumption that the size of initial meniscus neck is connected with the diameter of attachment area of nanobubble. There are no nanobubbles on the surface of hydrophilic minerals, and the liquid film rupture is hampered in this case. Since liquid film stability is mainly affected by hydrophobic interaction, the liquid film rupture thickness is larger on hydrophilic minerals than on hydrophobic minerals. Selectivity of foam separation of minerals, governed by the chemically attached agents, depends on the ratio of the critical rupture thicknesses of the liquid film.

The article describes modeling and analysis of formation, attachment and dissolving of mineral substances on surface of diamond crystals. Based on the thermodynamic analysis and experimental research, the author validates deposition of chemical compounds as the main factor to govern mineral formations on natural diamond surface under contact with mineralized water in the occurrence conditions of kimberlite ore and during mining and processing. The efficiency of electrochemically modified water in dissolving and removal of mineral formations from diamond surface is ascertained.

The authors study potential of utilizing oil tailings of a lead-zinc processing plant. Conversion of sulfides into marketable selective concentrates is carried out in two stages: sulfide product is extracted from tailings, first, and processed, second, jointly with current ore material, using the accepted technology, or separately, by jet flotation. Sulfides are extracted from tailings using a channel-type hydroseparator. A feature of flotation scheme is jet counterflow of feed (in both cycles) and rough concentrate. Conditions and composition are developed for manufacturing a quality product from non-metallic tailings: lime-sand bricks, glass containers, fiberglass and marbled glass.

The hypergenesis zone processes are considered in regard to oxidation of metallic sulfides that deteriorate regional ecology due to transformation of hypogene sulfides in sulfate group minerals featured with high solubility and movability in the hypergenesis zone during summer monsoon in the coastal areas. The main agents of humid technogenesis are rainfalls rich in oxygen and other gases, that, with the help of the newly formed sulfuric acid, generate chemical oxidation and transformation of prime sulfides in oxidized groups of highly soluble sulfates.

The authors have developed the barrier shielding method to seal coal bed methane drainage holes. The method reduces air leakage from enclosing rocks to evacuation holes. The compositions of shields with external seal preventing from fluid leakage to ambiance are offered and analyzed.