Vol 52, No 1 (2016)

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 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. Powerful mining industry in the Murmansk Region also induces many seismic events. This article analyzes natural and induced seismicity and their cross-effect.

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.

an increasing use is being made of models for studying powered support system. The main aim of this research work is to design the power support system that is designed for the longwall face which operating in different geological conditions with the use of successfully empirical and modeling technics which takes into account the health of the hydraulics supports, the efficiency of the hydraulic supply system and the cleanliness/load bearing capacity of roof is also suggested, enabling management to ensure that the support system is used at maximum efficiency.

The article reviews in brief application of cyclical-and-continuous method in the conveyor-andtruck 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 crushand- 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 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 enhances 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 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 such machines.

This paper discusses about the robust machine “Dragline”, from century old techniques employed for power transmission, control and operation to the recent trends. Dragline is mostly used in mining sector for removal of overburden as it is highly economical in comparison to the usage of shovel–dumper combination of the same, however the deployment of dragline is subjected to the geographical conditions of the mine. Dragline in general mostly comprises Drag, Hoist and Swing mechanism. For the Drag, Hoist and Swing operations earlier DC machines are used with Ward–Leonard control mechanism, but recently due to advancements in power electronic devices AC motors found their application for the same due to their less maintenance costs and also reducing the number of machines resulting in increasing the overall efficiency. Also, gear less power transmission techniques are in place. In parallel, the control techniques are also getting evolved and automation is taking place starting with Swing mechanism extending to the whole operation.

The key mechanisms of selective recovery of manganese ions from mine water by combination of chemical and electrochemical methods are studied. The authors present 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 for generation of dispersed phase manganese by electric treatment of acid mine water at copper–sulfide deposits is offered.

Aqueous micro-emulsions of dibutyl dixantogen as an active compound of commercial 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 dixantogen 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 micro-emulsions is examined using the atomic-force microscopy method and colloid probe (SiO₂ micro-sphere). The long-range highamplitude attraction forces, probably of capillary nature, are revealed between the probe and substrata after the contact with dixantogen 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 dixantogen.

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.