In this article, variants of technological designing of new mining enterprise levels for obtaining the skills of engineering task execution are considered. The complex approach for the justification of a mine's parameters is examined. The combinations of quantitative and qualitative parameters for designing new coal-face and preparation works, transport, ventilation, and draining-out of gases, pumping, and mineral deposits while keeping cost reduction in mind for all stages of mining enterprise operations are presented. The obtained results allow us to lay the foundations for optimizing the parameters of the development system and the rational order for the coal reserves, under the changing mining and geological conditions of coal field deposit development. Conclusions regarding the implementation of the multivariance solutions in new coal mine level designing are made on the basis of undertaken investigations. The obtained results with sufficient accuracy in a practical application can be used to determine the development of new coal mine levels.

Paper presents the research results of the relationship revealed between the mined ore dilution factors and the geological structure and properties of the hanging wall rocks. The research methodology is in the analysis of the structure and properties of the hanging wall rocks, the technological parameters of the stopes in contact with the host rocks, the processing of actual surveying data of the rockfall volumes and dilution factors, the construction of a 3D model of the mined floor with the stopes divided according to the sequence of mining. The peculiarities have been revealed of changing the geological structure along the strike of the ore deposit with a characteristic distinguished tendency to decreasing the hardness of hanging wall rocks, the angle of the ore deposit slope, increasing the deposit thickness and replacing the morphological composition of the rocks with the division into 3 characteristic differing areas. New patterns and empirical equations have been determined for changing the ore dilution value in the primary stopes depending on the type, hardness coefficient and the contact area of the hanging wall rocks with the inclined outcropping of the stopes. A multiple regression equation has been obtained of the relation between the primary stopes dilution with the rocks hardness within f = 11 – 15 and the contact area of the stopes with rocks 780 – 2010 m2. The regression model variability of 85.96% evidences its reliability and representativeness. The methodological approach proposed in the paper can be used to develop an improved methodology for predicting the mined ores dilution when mining the Pivdenno-Bilozirske field, supplemented by a more complete data set to increase reliability.

The paper gives information on the engineering solution concerning the extraction of thin coal seams with partial backfill of the worked-out area. Geomechanical model of coal-bearing rock mass has been substantiated. A technique to carry out computational experiment aimed at the processes of coal-bearing rock mass displacement within a zone of extraction influence has been represented. Curves of rock pressure stress components distribution (i.e. horizontal stresses, vertical stresses, and stress intensity) within the front bearing pressure and worked-out area for traditional methods (if roof is controlled by means of complete rockfall) and for selective mining with partial backfill have been plotted. Relying upon the carried out studies of stress-strain state of coal-bearing rock mass, overall conclusion has been made on the advantage of selective mining with partial backfill from the viewpoint of geomechanics of the rock mass behaviour.

The objective of this work is to develop the technological measures for liquidation of technogenic disturbances that have arisen within the residential areas. Based on the results of geophysical studies, the causes and factors of Earth’s surface caving occurrence that arose in the result of natural-technogenic processes activation in underworked massif and are caused by the soil subsidence under buildings and constructions, have been determined. The solution of the problem was carried out with the use of methods for observing the natural pulsed electromagnetic field of the Earth and electric tomography in the area adjacent to the place of caving. The conclusions about the possible causes of the caving trough formation and its further development have been formulated, as well as the technological scheme for its liquidation have been developed. The developed new technological scheme allows conducting the effective liquidation works in conditions of proximity to the residential buildings and maximally reduces these scopes of works at ecological and protective measures.

Purpose. The research purpose is to develop a mathematical model of a pressureless flow in a channel with the occurrence in some areas of overflow layer through the wall. Using this model, it is possible to calculate the overflow layer height and length, as well as the change in flow rate in the channel due to the withdrawal of part of the fluid as a result of the overflow. Methods. The research uses a comprehensive multi-stage analytical approach. Firstly, in order to develop a mathematical model for a pressureless flow in the channel with the occurrence in some areas of overflow layer through the wall, this research analytically determines the dependence of the flow rate through the channel wall based on formulas for calculating the weir discharge coefficient. At the second stage, a mathematical model of a hydraulic mixture pressureless flow in a rectangular channel with an overflow through the wall is developed to determine the parameters and flow regimes of the stream. Findings. The dependences of the dimensionless height of the overflow through the channel wall and the effective critical flow depth on the dimensionless current channel length have been obtained for various values of the acting force parameters and the process parameter of the fluid overflow through the channel wall. This made it possible to study the dynamics of changes in these values along the channel for various values of the specified parameters, and to assess the degree of influence of the relevant factors on the characteristics of the pressureless flow along the channel and the process of fluid overflow through wall. Originality. For the first time, the model of the pressureless flow in the channel is generalized for the case of occurrence in some areas of overflow layer through the wall, when the length and height of the overflow layer are not determined by a hole in the side surface, but are controlled by a decrease in the corresponding flow rate. For the first time, this model makes it possible to calculate the height and length of the overflow layer and the change in the flow rate in the channel due to the withdrawal of part of the fluid as a result of the overflow in cases of overflowing condition of the channel with the stream under unstable and non-calculated flow regimes. Practical implications. The mathematical model and the calculation results can be used to ensure the environmental safety of the logistics systems of mining enterprises, as well as to assess the volume of the environmental pollution in case of overflowing through the wall of the channels of pressureless hydraulic transportation of waste from mineral processing and metallurgical plants.

A simple mechanical method (grinding and sieving) was proposed to separate the composite into carotenoid-enriched and LDH-enriched materials. The method is based on the internal self-abrasion of the composite when grinding solid particles of LDH as grinding bodies. When removing carotenoids in the form of a composite, rapid precipitation of the sediment and ease of filtration under vacuum were found. X-ray diffraction analysis showed that the composite and products of its separation contain X-ray amorphous Zn-Al LDH, an oxide phase, and an amorphous phase of carotenoids. The method of dichloroethane extraction proved the effectiveness of the composite separation process. It was shown that for the optimal amount of Zn-Al LDH, the content of carotenoids in carotenoid-enriched material was 24.4 %, and in LDH-enriched – 4.4 %. For these conditions, it was found that the total yield of carotenoids was 184.3 mg/100 g of pumpkin pulp, of which 155.4 mg/100 g was in the carotenoid-enriched material and 28.9 mg/100 g was in the LDH-enriched material. A hypothesis was expressed regarding the chemical nature of the interaction of carotenoids and LDH in the composite due to π-d interaction. The resulting carotenoid-containing materials can be used as food additives or processed to obtain purified carotenoids.

Nickel hydroxides are widely used as electrochemically active substances in alkaline batteries and hybrid supercapacitors; they can be used for electrocatalysis, in electrochemical sensors, and as pigments. Knowledge of the formation mechanism of nickel hydroxides is necessary for developing and optimizing targeted synthesis methods. The thermal effects of processes in the formation of nickel hydroxide from nitrate were studied by the calorimetry method. The mechanism of precipitate formation was investigated by the method of simultaneous potentiometric (with a glass universal electrode) and conductometric titration. The nickel content in the samples obtained at the determined NaOH/Ni2+ ratios was investigated by the chemical method of trilonometry after preliminary dissolution. Calorimetric investigations showed that the reaction of nickel nitrate with NaOH was exothermic with ΔНreaction=‒28328.5 J/mol. The exothermic nature of the NaOH dilution process was revealed with ΔНdilution =‒2454 J/mol. According to the results of potentiometric titration, the formation of a basic salt of the NiOHNO3 type was not detected. Analysis of the results of conductometric titration revealed a two-stage chemical mechanism for the formation of nickel hydroxide from nitrate. At the first stage, which had a high rate, due to the liquid-phase reaction of the nickel cation with the hydroxyl anion, a primary precipitate of the composition Ni(OH)1.87(NO3)0.13 was formed. In the second stage, as a result of a slow topochemical reaction of the primary precipitate with hydroxyl anions, nitrate ions were displaced from the precipitate to form nickel hydroxide. These data are confirmed by the analysis of precipitate obtained at NaOH/Ni2+ ratios of 1.87 and 2.2: the Ni content was 52.95 % and 55.63 %, corresponding to the formulas Ni(OH)1.87(NO3)0.13∙0.68H2O and Ni(OH)2∙0.71H2O. This clearly indicated that the primary precipitate was nitrate-doped α-Ni(OH)2 and the final precipitate corresponded to the α-modification of nickel hydroxide

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