Vol 54, No 1 (2018)

In the framework of the theory of interaction between nonlinear geomechanical and physicochemical processes in coal seams under mining and based on the piston mechanism of gas dynamic processes, it has experimentally been proved that nonlinear quasi-metric elastic pendulum waves from natural and induced earthquakes have influence on gas-dynamics in mines in Kuzbass. The objects selected to identify the interrelationship were the large earthquakes occurred in Kuzbass on November 9, 2016 (magnitudes 2.7 and 3.7) and the records of the quake-induced gas dynamic activity in the Alarda and Osinniki mines.

Stress memory in consolidating composites in acoustic emission is studied experimentally to understand feasibility of its application in stress state control in rock mass. The tests show that, owing to uniformity and comparatively high responsiveness of acoustic emission behavior under straining, composite materials, when placed in a geomedium, allow highly accurate identification of tensor of actual stresses in it.

The results of experimental and analytical studies into the state of access roadways under selvedges of gently dipping sedimentary sheet-like bodies are presented. The stresses in rock mass under the selvedges of seams are determined. The state criterion was assumed the ratio of the maximal compressive stresses at boundary of a reference circular cross section roadway in an elastic medium and at the boundary of the roadway under the hydrostatic stress field. The results of the instrumental and visual observations in mines as well as the data of equivalent material modeling and analytical solutions agree.

In terms of the complex-structure ferruginous quartzite ore body mining in the Kursk Magnetic Anomaly, the authors validate the requirement to account for anisotropy of rocks with a view to improving performance of preparatory and blasting operations, stabilizing grain size composition, reducing production of oversizes, saving energy input of milling, enhancing useful component extraction into concentrate and decreasing losses with regard to the sound subsoil management conditions. The effect of the first to third scale anisotropy on the quality of blasting fragmentation of ferruginous quartzite is analyzed. The theoretical formulas to calculate radius of controlled fragmentation zone as function of geological and geophysical characteristics of rock mass are presented, and the practical results of blasting at open pit mines in the Kursk Magnetic Anomaly area are described.

Water well drilling-with-casing equipment is described in the article. Construction diagrams and field test results of series-production and new drilling-with-casing DTH hammers possessing higher impact energy are analyzed. The economic study of water well drilling cost in geological conditions of the Republic of Altai is performed.

The problem connected with the optimization of cutting width of a shearer loader based on the maximum capacity criterion with regard to physical properties and fractional composition of coal is formulated and solved. Aimed at calculating shearer loader feed and capacity as function of cutting width, it is proposed to use shearing stress and contortion of seams instead of cuttability of rocks. It is found that in order to improve coal sizing and reduce methane release in longwall face, as well as for the uniform distribution of loads on picks, the picks should be arranged on the drum at unequal spacing in accord with the exponential law.

It is found that the slope of access roads influences adds to flattening of nonmining pit walls where the access roads are driven. Aiming to determine the over-flattening of nonmining pit walls, the quick and accurate analytical method is developed. It is proved that the increase of the slope of access roads to the maximum possible values (20–24%) enables reduction in stripping by 20–40% in deep open pit mines. The mining efficiency in case of steep slopes, aside from extra flattening of nonmining pit walls, is also influenced by the depth of transition to such slopes and the transportation capacity of the access roads depending on distribution of mining operations along the depth of an open pit mine. It is demonstrated that it is most reasonable to gradually increase the slope of access roads with the mining depth, starting from the initial value (8%) and up to the maximum governed by technical requirements and operating conditions.

The method of dynamic loading of sucker-rod pumps to act upon the producing well bottom zone is described. The effect is exerted through an underpump stem set on the well bottom. Under the weight of the flow string, the underpump stem loses pitch stability and is pressed to the inner surface of casing pipes. The operating sucker-rod pump induces axial vibration in the string, which generates lateral stresses transmitted to the adjacent rock mass along the spiral contact line between the underpump stem and the casing pipes. This dynamic impact on inactive or slightly active interlayers invokes fluid flow in them and results in enhanced production of wells. The field test data are presented to illustrate the described effect in wells in different geological conditions.

The main objective of mine ventilation network optimization studies is to develop a reasonable method for ventilation system control that minimizes the total cost of mine ventilation. The fundamental principles for ventilation network optimization are discussed, and a multi-objective optimization model is established from the viewpoint of total cost. Furthermore, an optimization algorithm based on the airflow asymptotic calculation is presented by the hierarchical analysis of objective functions and analysis of the structure characteristics of a ventilation network. In the proposed approach, the regulated branches are determined by the directed path matrix; the optimal solution is obtained by airflow asymptotic calculation using the existing software for ventilation network analysis, and it does not need to solve the large-scale nonlinear programming problem. The results of example analysis validated the reliability of this approach.

Using ultraviolet-visible spectrophotometry and laser and electron microscopy, adsorption of cyanuric triamide agent (CTA) at the surface of silver-rich galena PbS-Ag and pyrite FeS2-Ag is recorded. The X-ray spectrum of the new reagent phase on silver particles contains O, C and N bands typical of CTA. New experimental data on kinetics of selective flocculation of ultrafine particles of silver-bearing sulphide minerals under treatment by CTA and thermomorphic polymers (TMP) are obtained. It is found that CTA and TMP introduced jointly in sulphide slime pulp accelerate settling of slime fractions, which promotes mineral aggregation and improves flotation performance. The prospects of using CTA and TMP as modifiers in flocculation of slime fractions of silver-bearing minerals are demonstrated.

The process of leaching oxidized nickel ore in sulphuric acid with the additives of sodium sulfite and fluoride is investigated. Tochilnogorsky deposit ore (Sverdlovsk Region) is used to prove theoretically and experimentally efficient application of fluoride in dissociation of nickel minerals (nontronite and garnierite) in oxidized nickel ore. It is shown that at NaF consumption of 10 kg/t, it is possible to enhance maximum extraction of nickel to solution from 82.3–86.9 to 96.0–98.7% at the residual sulphuric acid concentration of 10–20 g/l in the working bath. It is found that the sodium fluoride additives lower the process activation energy from 22.8 to 12.9 kJ/mole. This means that the reaction of sulphuric-acid leaching proceeds in diffusion–kinetic mode and that sodium fluoride is applicable as the leaching accelerator.

The current technologies available in the world market for the chemical processing of caustobioliths of carbonic series are overviewed. The prospects for the expansion of the coal supply base in the Far East of Russia are discussed, and the main lines of advancement in the coal preparation industry are specified. It is possible to arrange coal chemistry clusters in the Amur Region (thermal conversion of coal, production of Montana wax and oxidized humite), in the Khabarovsk Territory (in-situ gasification) and in the Primorye (motor fuel and liquid fuel production).

The economic and ecological recommendations on integrated and efficient management are made for the Dashkesan Mine in the north-east of the Small Caucasus and for sulphide–complex ore deposits on the South Slope of the Big Caucasus with a view to applying modern methods and resource-saving technologies in extraction of basic metals and alloy elements, management of mining waste, dust and gases, reducing production cost and environmental protection.

As a component of multi-functional safety control, the man–machine mine shaft alarm system ensures safe conveyance of personnel and cargo in mines. The designed interfaces, circuits and architectures, hot backup and the objective-coordinated communication protocols guarantee strict orderliness, reliability and safety of mine control.

In the published version there is an error in the formula of air flow rate per second in equation (8). The present form in this erratum is the correct: