Home – Home – Jornals – Advanced Search

The authors show that data on characteristics of drill mud penetration zone improve reliability of geoinformation obtained from borehole geology and geophysics. The developed procedure for the data interpretation takes into account the geomechanics and hydrodynamics of drilling. A part of the drill mud penetration zone is represented by mudcake which prevents direct measurement of porosity and permeability. The article describes the experimental studies on growth of the mudcake on the samples of low-permeable sandstone from the Jurassic reservoir rock mass using an original facility. The petrophysical nonuniformity of the mudcake was determined. The repeated measurements revealed the mudding zone.

The article describes the numerical studies on propagation of hydraulic fracture in the nonuniform-stress elastic environment around a cylindrical cavity. The modeling used the extended method of finite elements. The scope of the modeling embraced different variants of the principal stress orientation relative to the cavity and a disk-shaped initiation fracture. The influence of the stress ratio and stress level on the fracture path is described. The main types of the created fractures are shown. The conditions when the created fracture reaches the cavity surface or propagates along it are analyzed. The features of the fracture propagation and opening pressure are described for the fractures of various shapes depending on the volume of the injection fluid.

The article presents the design model and results for the main crack development in closely spaced blasting in brittle rocks. The 3D modeling is described as case-study of crack formation in granite in perimeter blasting of ammonite charges at different spacing and filling of blastholes. The shapes and sizes are determined for the main cracks generated by blasting of single charge and three close-spaced charges. From the modeling results obtained for a specific charge, the method is proposed to determine efficient spacing of blastholes in perimeter blasting to ensure the maximal area of the created crack.

The authors developed the phenomenological model of landslide initiation under multiple seismic effects. The model uses the lab-scale testing data on mechanisms of slope failure under dynamic impacts, the analysis of a large bulk of field data, the instrumental measurements of seismic effects induced by large-scale blasting and the numerical calculations of influence exerted by seismic vibrations on slopes. The rules are formulated for the decision-making in evaluation of potential landslide initiation under seismic impact. Evaluation of slope stability is performed for overburden rock dumps at open pit mines in the Kursk Magnetic Anomaly. It is shown that large-scale blasts in the test open pit mine have no effect on the stability of the dumps, but the damaged drainage and the rising of underground water can result in accumulation of irreversible deformations.

The article presents the optimization design results for impellers of axial fans for main ventilation in mines using the criteria of minimum mass and required stress level in fan assemblies. The design of a single disk impeller is justified. For high-duty fans having the blade tip speed of 200-220 m/s, the topology optimization is performed for the single-disk impeller. The dependence between the design parameters of the impeller components and the speed of the fan rotor is determined. The topology optimization is implemented with SIMP in ANSYS.

The article describes the theoretical and experimental research data on possibility to improve the quality of the end concentrates of float-and-sink, X-ray luminescent, adhesive and froth separation. The method of nitride hardening is proposed for ferrosilicium grain surface with the hardened layer depth in the range of 30-60 nm for reducing ferrosilicium corrosion rate by 2.7 times at the preserved process properties. The necessity of adding the primary float-and-sink flotation circuit with two-stage magnetic separation to decrease the yield of rough concentrates and to improve their quality owing to removal of 29-95% of siderite. The optimized composition of luminophore-bearing modifying agent ensures complete recovery of earlier unrecoverable diamonds in concentrate at the maximum kimberlite yield of 2.5%. The workbench test processing of difficult diamond-bearing raw materials proves the possibility of incremental diamond concentration in adhesive and froth separation (by 14.0% and 12.7%, respectively), and in the cycle of finishing operations in X-ray luminescent separation (by 25.3%) owing to modification of surface properties of diamond crystals using physicochemical methods and energy deposition.

In order to realize the rational utilization of low-grade polymetallic symbiotic mineral resources with low input, typical copper-nickel symbiotic low-grade ores were used as the test object. After careful process mineralogy research on the ore, it was learned that the main valuable elements of the ore were Cu and Ni, and the content of these two elements was 0.16 wt.% and 0.39 wt.%, respectively. The main copper-bearing mineral in the ore was chalcopyrite, and the main nickel-bearing mineral was pentlandite. Useful minerals were finely distributed in ores. Based on the properties of ore, a beneficiation process of one stage grinding → copper/nickel mixed flotation → copper/nickel separation was proposed. A copper concentrate with a Cu grade of 17.08 wt.% and a nickel concentrate with a Ni grade of 4.63 wt.% were obtained by separation. This study provides a low-investment technical solution for the rational utilization of polymetallic paragenetic mineral resources.

The prospects for ecologization of technological paradigm of development in the sector of mineral resources are studied and substantiated with regard to the requirements and constraints, and based on the equal possibilities for the biosphere and technosphere. The notion of the nature-like technologies is structured subject to the coincidence of missions of the content-rich components in the natural and geotechnical systems. The methodology of the homeostatic transformation of the biological system functions into the structure of a cluster on the convergent mining technologies is presented.

The supply of coal-fired thermal power plants with limestone as a sorbent in the flue gas desulfurization process highlights two key issues. Apart from the raw material quality adequate to meet the technological conditions of the installed desulfurization plants in thermal power systems with several potential production and user entities, the question of rational limestone supply arises. The paper presents a multi-attribute ranking model as a possible approach to solving such tasks.

The paper presents the single-criterion modeling of limestone supply under the conditions of the variable structure of the thermal power complex of Serbia. In the end, the paper provides an analysis of the differences between multi-attribute and single-criterion solutions.