Home – Home – Jornals – Journal of Mining Sciences 2013 number 1

The authors have designed a test stand for origination and growth of discontinuities in rocks. Based on the laboratory experiment data obtained on artificial geomaterials and using the developed geomechanical model, equation of state for shear deformation of a discontinuity is synthesized.

The paper presents analytical solution for hydraulic fracture driven by a non-Newtonian fluid and propagating under plane strain conditions in cross sections parallel to the fracture front. Conclusions are drawn on the influence of the fluid properties on the fracture propagation.

The authors analyze numerically propagation of hydraulic fractures from a circular hole boundary under viscous fluid injection in plane deformation condition, considering influence of the fluid viscosity and elastic characteristics. The approximate solution is compared with the recent numerical calculations of exact formulated problem. Effect of configuration of incipient hydraulic fractures on development of the overall hydrofracturing pattern is analyzed, and stable growth conditions for several long fractures are found.

The article proposes mathematical model of heat exchange between open pitwall and atmosphere for forecasting temperature field in permafrost strata, daily change in radiative balance; slope angle and surface orientation; influence of contiguous benches. In terms of Udachny Mine, time dependence of pitwall sloughing layer thickness is estimated under cyclic effect of freezing–defrostation in rocks having different freeze resistance.

The authors analyze stress–strain state of elastic plane with circular void in varied loading conditions, draw energy flow lines, highlight effect of clustered seismic events on the flow line shape, and propose definition of rockburst probability.

The article considers statistical properties of surfaces of sylvinite, spathic salt and carnallite grains in nanorange. The authors describe processed experimental data obtained on scanning microprobe Dimension ICON in nanorange for grains of the Upper Kama potassium and potash-magnesium rock salts. Fractal dimension determined by minimum covering method is used as a characteristic of the grain surface irregularity. The authors find differences in the statistic properties of one-dimension divergent cuts of the grain surfaces.

The author studies buoyancy of pontoons used in open pit coal mines based on the fundamental principles of the ship theory and finds safe height of pontoon upperworks. The derived formulas for metacentric heights are used in the analysis of pontoon stability.

The authors have developed and numerically analyzed model of near-field range of a percussion-type borehole seismic source emission. The obtained estimates of attack energy on productive strata at underspeed seismic waves and varied position of the source relative to the stratum are presented in the article.

Meeting production targets in terms of ore quantity and quality is critical for a successful mining operation. In-situ grade variability and uncertainty about the spatial distribution of ore and quality parameter cause both deviations from production targets and general financial deficits. A stochastic integer programming formulation (SIP) is developed herein to integrate geological uncertainty described by sets of equally possible scenarios of the unknown orebody. The SIP formulation accounts not only for discounted cashflows and deviations from production targets, discounts geological risk, while accounting for practical mining. Application at an iron ore deposit in western Australia shows the ability of the approach to control risk of deviating from production targets over time. Comparison shows that the stochastically generated mine plan exhibits less risk in deviating from quality targets that the traditional mine planning approach based on a single interpolated orebody model.

The article reviews backfilling complexes operating at Kazakhstan mines and describes laboratory and industrial tests of effect of cement–ash binder and plastifier combination on rheological properties and strength of filling masses.

Simultaneous extraction of ore reserves from open pitwall and the layer immediately adjacent to the open pit bottom results in higher volume of ore discharge in the limited bottom area, besides the bottom must be stable within the adjacent layer extraction interval. The authors select the pit bottom design with two-way alternate arrangement of loading entries, taking into account the use of power-driven load–haul–dumpers. The ore output with the given pit bottom design is evaluated.

Considering peculiarities of resource potential in spoil dumps after gold placer mining and based on the analysis of spoil dump samples taken in two large gold placer mines, the article illustrates renewability of the resources left in spoil dumps under effect of natural processes (low-temperature, gravity water flow, suffosion, etc.).

The authors discuss how design elements of replaceable rotatable blade ring influence its stress–strain state and natural frequency. The constructed generalized dimensionless model of adaptable blade ring assists in designing axial fans with increased rotation velocity for improved performance of main mine fans.

The authors have developed procedure for forecasting air flow, air and rock temperatures as well as thawing halo in all roadways of a mine, taking into account stage-wise introduction of new mine workings in the mine ventilation network, or backfilling of the mined-out stopes.

The article analyzes flotation and adsorption capacity of a new complexing reagent AMD (nitrogen and oxygenated organic compound belonging to phenylpyrazole class) toward sphalerite, chalcopyrite and pyrite, combined with complexing modifiers, at varied consumptions of the reagents, in wide range of alkalinity. The basis for improvement of pyrite and sphalerite separation in flotation is provided.

Based on analysis of estimation criteria for chemical resistance of nonferrous and rare metal minerals, it has been found possible to properly predict their reactivity prior to their mechanical activation reasoning from their energy density, bond uniformity and power characteristic of cations of oxygen compounds. The authors propose relationships for determination of structural changes in noble metal minerals under mechanoactivation, which ensure mineral opening under further hydrometallurgical treatment (temperatures under 100 ºC). These relationships are useful to pre-evaluate reactivity of minerals and, based on that, select effective mechanical activation conditions.

The article presents basic magnetic characteristics of nine prime concentrates obtained from Siberian black iron ore and lightly oxidized iron ore processed at Abagur Sinter and Enrichment Plant. The best magnetic properties belong to prime concentrate of black iron ore extracted from Abaza, Irba and Kaz deposits; the weakest properties characterize lightly oxidized ore from Izykh-Gola and Krasnokamensk; the values of magnetic characteristics are proportional to magnetite content of original sample. Considering this, it is recommended to process jointly lightly oxidized and black iron ore in order to reduce magnetite loss in tailings.

The currentness of space data application in local and regional real-time estimation of state of nature in a mining area is substantiated in the article. The authors give and analyze satellite measurements of state of natural environment in a mining area in terms of open cut Olimpiada Gold Mine, Krasnoyarsk Territory.

In terms of Mnogovershinny gold and silver mine, the authors have made geological estimation of mining impact on natural environment using geoinformation technologies. The influence area of mining and processing has been zoned based on the complex air pollution index using earth remote sensing methods.