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The authors present the formulation and solution of a problem on the efficient engineering data of multi-drive high-duty belts for bulk coal. The theoretical framework for calculating the belt thrust includes the main equation of the belt conveyor dynamics, and features of calculations in stationary mode and in starting conditions with the regard to horizontal and vertical curvature of the belt route. The rational width and production capacity of a belt conveyor are substantiated. The hauling power and capacity of drives of a multi-drive belt are calculated. The strength test of a selected belt is performed. The calculation using the developed program LENTA 1.0 is presented as a case-study of a multi-drive belt conveyor in Inaglinskaya Mine in the South Yakutia coal field.

The structural layouts of pneumatic percussion machines are reviewed. The use of a pneumatic percussion machines with mixed-type air distribution via elastic valve is substantiated for implementation of adaptive technologies. The authors present the theoretical and experimental studies into dynamics of duty cycle of a pneumatic percussion tool with on-line power adjustability.

A brief literature review on flotation of calcium-bearing minerals is given. It is found that flotation activity of a collector is connected with physisorption of the collector in particle-bubble attachment. The tests prove that physisorption decrease reduces recovery and increases the useful component content /yield ratio in the concentrate. The found correlation is a framework for new approaches to quality improvement of flotation concentrates. The method proposed to select compositions of collectors can enhance selectivity of extraction of useful minerals.

The authors have correlated the fluorescence spectrum with the spectrum and kinetics of X-ray luminescence of organic collectors. The correlations prove applicability of organic collectors with modifying agents. From the integrated evaluation of organic liquids by the criteria of their adhesion capacity relative to diamonds and extraction capacity relative to inorganic luminophores, the selected organic collectors are: diesel, heavy gasoil of catalytic cracking, and their mixture. The spectral functions of organic luminophores contained in organic collectors are replaceable with polyaromatic hydrocarbons which generate intense signals similar to the signals of organic luminophores. Efficiency of modifying agents containing organic collectors and hydrophobic luminophores E-515-115-G5 and FL-530-GZ is high. The test organic collector was heavy gas oil of catalytic cracking and diesel fraction at a ratio of 61-9:1. Recovery of weakly and abnormally fluorescent diamonds was 80-90%, while recovery of kimberlite was not higher than 1%. The results allow recommending the developed modifying agents for the commercial-scale X-ray luminescence separation of diamond-bearing materials.

The article proves the promising nature of using functionalized magnetic nano particles in extraction of metals from process solutions and in treatment of industrial effluents. The experimental copper extraction from solutions using a magnetic nanosorbent made of lipoic acid-functionalized magnetite is described. Sorption efficiency is determined as function of the initial concentration of solutions as compared with non-functionalized nano-size magnetite. The copper-bearing sedimentation mechanism includes chemosorption at active centers of lipoic acid, adsorption at clean magnetite surface and re-crystallization of sorbate in intrinsic copper-bearing phases. The phase composition of copper in the sediments is examined, and the copper extractability is illustrated. The conditioning technology is proposed for copper-bearing solutions. The stage-wise use of the magnetic nanosorbent enables process solution purification up to the maximum allowable concentration at simultaneous production of a concentrate suitable for hydrometallurgical processing.

The test of gold-bearing humic substances aimed to find forms of gold in them. The test results enable estimation of gold compound mobility during sedimentation of humic acids. Re-sedimentation of humic acids shows similar properties of gold after dissolving with and without a selective dissolver. The amino-acid analysis of humic acids before and after their interaction with ammonium hydroxide reveals the increased content of amino acids capable to dissolve gold. Stage-wise spin of gold-bearing liquid humic acids at acceleration from 4000g to 233000g and at pH of 11 nullifies gold-bearing particles in solutions and makes the latter homogenous. The authors describe the impact of destructive effects relative to organic compounds on joint sedimentation of gold and humic acids.

The post-leaching of silver (Ag) from a non-sulfide lead-zinc (Pb-Zn) ore flotation tailing leach residue in a copper-ammonium thiosulfate solution was investigated. Ag (89.7%) was extracted into the leaching solution under the following conditions: 30 g/l ammonium thiosulfate, 0.5 g/l copper sulfate, 25°C leaching temperature and 4 h leaching time. On the basis of the experimental results, a fuzzy logic prediction was made. Ammonium thiosulfate, copper sulfate and leaching period were chosen as predictive criteria in this step. The fuzzy prediction model was found to be very consistent with the experimental data (R²:0.9657). Based on these findings, the application of the fuzzy logic prediction approach to the silver dissolution from the leach residue could be considered.

The authors discuss concentration of chemical elements in underspoil water subject to a season and to climatic conditions. The features of underspoil water composition are analyzed with respect to chemical composition of spoil rocks in water and acid extracts. Majority of the test elements correlate well with their composition in the acid extract and with the spoil rocks composition. The water extract is assumed to be unreliable to predict composition of underspoil water.

The article analyzes the impact of water inflow in a mine on the efficiency of the main mine water drainage system as a case-study of Udachny Mine, ALROSA. It is found that the content of solid particles in mine water grows with the increasing water inflow in the mine. A method is proposed to eliminate excessive water inflow in the mine in warm season in case of a pumping station teardown because of the spoil bank slide. The expected payback time of the proposed engineering solution is calculated.

The authors attempt the numerical modeling of the geomechanical behavior of a rock mass in the course of single unit face longwall mining. The calculation models are constructed for the rock mass geomechanics from ground surface down to mining depth. The model problems are solved in two and in three dimensions. The resultant characteristics of a trough subsidence on ground surface were compared with the data of engineering analysis. The modeling results are verified using actual in-situ observations of check point subsidence. The comparative analysis of the trough subsidence characteristics on ground surface from the geomechanical modeling and engineering analysis show their correlation in case of all test alternatives.