Home – Home – Jornals – Journal of Mining Sciences 2017 number 2

For theoretical description of interaction between geomechanical and physicochemical processes in multiphase coal seams, the author for the first time proves the existence of an analytic “extension” of the operator connecting Langmuir’s equation and the kinematic expression for pendulum waves in high- stress geomedia of hierarchical block structure.

The first results of the experiments on influence of fluid injection on the mode of interblock contact deformation are reported. It is found that deformation energy consumed to radiate seismic waves largely depends on parameters of fluid injected in fracture. Dilatant fluid appears to be the most efficient in the decrease of the seismic energy as the fluid viscosity grows with the rate of deformation. In the laboratory test, the slip-stick motion mode transforms into the quasi-stable creep in a single deformation cycle after fluid injection.

A new approach to local rockburst hazard problems and rockburst prediction is demonstrated in terms of acoustic measurements in two mine workings of Joint Kirov Mine, Apatit. The new approach is based on spectrum-correlation analysis of acoustic emission signals, on the one hand, and on the Griffith-Irwin fracture model, on the other hand. Acoustic emission signals are recorded using new-generation portable system Prognoz-L for local rockburst hazard monitoring. Prognoz-L provides digital recording and processing of a wide range of acoustic signal parameters. The analysis of spectrum parameters of the recorded signals confirms applicability of the innovative software/hardware system to predict dynamic events in rock masses.

The author studies stability of a structure (platform) on a pile foundation using physical modeling. Disturbing force is applied by a pendulum generating seismic impulse vibrations. The data on measured displacements of two points on the platform surface are used to find the platform incline under varied number of blows, blow energy, distance to the blow point and the platform weight.

The formulas and schemes are presented to determine the length of charges and their inert gaps. The calculations are based on the theory of superposition of seismic waves under blasting in rock mass. The proposed procedure enables calculating parameters of distributed charges under any ground and geotechnical conditions of blasting ensuring quality fragmentation, elimination of flyrock and reduction in drilling operations.

For the selective disintegration of kimberlite and dissociation of diamond crystals of undisturbed natural integrity, the authors have designed a tool with cutters having hardness lower than diamonds but higher than binding minerals in kimberlite. The article gives the results of testing the prototype of the heterogeneous material disintegrator on soft kimberlite extracted from Manchary pipe. The prototype includes disc brushes made of high-strength steel wire. The selective disintegration prototype is a preproduction model of lab, semi-commercial and commercial disintegrators. The method is applicable to recover hard particles from geological samples.

The researchers analyze energy processes running in an autonomous electric power system consisting of a synchronous permanent magnet generator and a semiconductor electrical energy converter. Current, voltage and capacity of key components of the system are evaluated, and the system operation modes are determined for the variable magnitude and character of applied load at the constant voltage output frequency. Parametrical law is proposed to control semiconductor converter serially connected to load and generating reactive power. The influence of the converter on the basic design parameters, energy specifications of the synchronous generator and the system as a whole are evaluated.

The authors identify some factors that govern energy input of borings removal from hole bottom to an unloading point using auger drilling string assembly. Of specific significance appears to be the factor of insufficient reliability of anchor gears and centering devices of the drilling string assembly, which makes continuous drilling impossible without permanent servicing. The article gives the analysis of bench testing data of bearings with antifriction filler for drilling string mounting groups to be serviced outside the areas of drill holes. The design solutions based on the investigation results and aimed to improve reliability of anchor gears and centering devices of an auger drilling string assembly are described.

New results that solve the important scientific task of providing electrical networks with an isolated neutral voltage up to 1000 V in mining enterprises are obtained. The method for measuring the admittance of insulation networks with isolated neutral voltages up to 1000 V, which will provide improved accuracy and speed measurement admittance network insulation, is described. The measurement is made by adjusting the additional conductance to ensure equal quantities of module phase voltage to earth and zero phase-sequence voltage. In this connection the additional conductance corresponds to the admittance of network. The simulation model of a method of measuring the admittance of insulation using the Matlab/Simulink environment is analyzed. The proposed method is simple, as the instrumentation, single-phase voltage transformers that are needed to measure the admittance of network, are in the service manual of the energy management companies.

The author analyzes the method to prevent gas-dynamic events during mechanized mining of karnallite at Upper Kama potassium-magnesium salt deposit. The method ensures efficient gas drainage and relaxation of outburst-hazardous rocks due to a horizontal drainage borehole slotter in the sidewall of a face entry. The data of the mine experimental studies are presented. The time behavior of residual gas content and air sorption indexes of karnallite in the influence zone of the drainage borehole slotter is determined. It has been found expedient to use borehole slotting to prevent gas-dynamic events during mechanized mining of karnallite.

Under discussion are the direct dumping flowsheets applied to remove lower overburden layers at coal series deposits in Kuzbass. The authors present the calculation procedure for the parameters of overburden excavation and re-excavation flowsheets using draglines. It is found how the re-excavation coefficient depends on the place and level of the dragline site. The recommendations on selecting the dragline route in internal dumping are made. The main trends toward expanding the area of application of the direct dumping technology are identified.

The author proposes a promising technology to separate monolith stones and preformed blocks for construction from rocks mass using a diamond rope cutting machine ensuring reduction in labor content, cost and loss as well as enhancing the process production output. The analytical model is developed, and the dependences between the material loss and the technology parameters are found. The main standards are formulated for the technology, and the ways of improving the diamond rope cutting machines design based on material loss minimization are specified.

It has been found that the rated and actual data on methane emission in production headings in some Kuzbass mines disagree. The air and gas control shows that actual methane emission from broken coal is much less than the rated data when a coal shearer has high advance velocity and production output. The authors demonstrate the connection between an average diameter of broken coal fragment, shearer advance velocity and drum rotation speed using Darcy’s law of flow and Langmuir’s adsorption equation. It is found that methane emission from broken coal and natural coalbed methane content relate nonlinearly and that the relationship of absolute methane emission, shear advance velocity and production output has an extremum.

The article gives new experimental data on chemistry, phase composition, structure and physicochemical properties of surface of minerals composing metasomatically altered kimberlite rocks. The authors have determined formation conditions and basic genetic types of mineral micro- and nano-size phases on diamond surface in the form of aluminosilicate minerals, thin coats of clayey minerals, calcite and dolomite bound with carbonate cement, as well as their negative effect on recovery of diamonds by foam separation. The mechanisms and efficient methods of combined energy effects on the natural heterogeneous system of diamond and surface mineral phase are found to rupture hydrophilic mineral films on diamond surface, prevent their repeated formation and reduce diamond loss in processing of diamond-bearing kimberlites.

The authors consider variants of multipurpose use of plant materials-ground green mass of Sosnovsky cow-parsnip. Simultaneous production of aqueous extract possessing depression properties and after-extraction solid residue being a sorbent for ions of gold and finely dispersed gold-bearing particles is one of the ways toward the reduction in cost and environmental impacts of flotation of gold-containing products. The SEM and UV spectrophotomery shows sorption activity of solid residue of cow-parsnip relative to Au³⁺ ions. It is demonstrated that the studied vegetable sorbent is applicable to additional recovery of finely dispersed gold from flotation pulp. The introduction of cow-parsnip instead of xanthogen in treatment of tailings has enhanced efficiency of fine gold recovery.

The experimental test data on magnetic properties of iron-bearing mineral waste materials under radiation-thermal treatment are presented. It is found that the volume magnetic susceptibility of pyrite- and arsenopyrite-containing waste has increased by 5 times on the average. The authors demonstrate that radiation-thermal magnetization and magnetic separation allows production of KOS-3 grade tin concentrate meeting fuming process requirements from waste of Novosibirsk Tin Works.

The article shows predictability of change in energy content and reactive capacity of standard wolframite concentrate after mechanical activation based on the data of X-ray structure analysis during later-on low-temperature (under 100 °С) alkali leaching. It is confirmed that the quantity of energy accumulated during mechanical activation as surface energy and microstrains influences efficiency of the later-on leaching. The authors derive a relation to calculate wolframite leaching recovery depending on structural change energy, initial coarseness and leaching regimes. The method of preliminary mechanical activation of wolframite and the process efficiency criteria offer conditions for energy-saving wolframite concentrate processing directly at mining and processing plants.

The authors present the data of the substance analysis of gold-copper-arsenic flotation concentrate. Gold and copper recovery by autoclave leaching of the concentrate has been studied. It is found that maximum gold and copper recovery under optimum conditions reaches 96 and 92%, respectively. The profitability of the proposed process flowsheet is proved by the technical-and-economical calculations.

The authors present the gravity concentration-and-flotation technology for joint processing of gold ore and placer gold mining waste ensuring high gold recovery. The research is carried out using samples of ore from a primary gold deposit under mining and from waste of gold placer mining in the Yano-Kolyma gold province in the Russian Federation. The feature of the technology is the use of bullion gold in the gold flotation circuit. Bullion gold is recovered from gold placer mining waste by gravity concentration. The ore and waste processing by gravity concentration and flotation is based on the stream flow of feed material and rough concentrate. The second flotation stream circuit uses the technology of aerosol column flotation. The efficiency of investment to joint processing of gold ore and placer gold mine waste is evaluated.

The application of integrated monitoring of ground subsidence, including geotechnical calculations of rock mass movements, leveling and satellite radar interferometry, is considered in terms of Karaganda Coal Basin. The satellite radar interferometry data show reliable measurement of ground subsidence as a consequence of underground mining.

The authors propose the approach to validation of the surveying control accuracy in safety monitoring of earth dams in terms of liquid waste receivers at mines. Based on the system structuring of types of earth dams and their elements, estimation of influence of loads and effects exerted to these structures, as well as the analysis of accident risks using the Hazard and Serviceability Analysis, an ideal sign model of earth dam safety monitoring has been constructed and the scope of field observation has been specified to record hazardous off-sets and prevent hydrodynamic accidents. By modeling an ideal earth dam, the authors determine the dam stress-strain state criteria. From the condition of non-admittance of limit equilibrium disturbance of the earthen structure, the requirements on the accuracy of horizontal and vertical surveying control over structural elements of dams are set.

The procedure of revealing water-saturated areas near underground openings by the data of radars with resistive-loaded antennas is developed. The key identifying parameter (attribute) of the procedure is the information entropy showing specific character of function of distribution of radar trace amplitudes. It becomes possible to distinguish anomalies in the profiles using the attribute after amplitude equalization. The procedure of processing of traces is described and exemplified, and the reasons of the entropy parameter efficiency are explained. For the comparison, the author considers alternative identifying parameters that appear less efficient as against the entropy attribute either for their weak capability to reveal anomalous sections in profiles or for the low interference immunity.