The article presents an analytical review of the current state of the iron ore base of the ferrous metallurgy of Russia and the world, identifies the largest iron ore provinces and iron ore producers. The promising directions of development and improvement of the quality of the iron ore base of Russia and the features of the development of new deposits of rich iron ores are identified. Effective technologies for the development of rich iron ores deposits that ensure an increase in production volumes are proposed. The geomechanical justification of rational technological parameters that are easily adapted to changes in mining and geological conditions has been performed. Based on the results of field studies, the use of an elastic-plastic model with the Coulomb – Mohr strength criterion for modeling changes in the stress-strain state of an ore rock mass during mining operations is justified and recommendations for ensuring the stability of mine workings are developed. Effective engineering and technical solutions for the complex development and deep processing of rich iron ores with the production of fractionated sinter ore, which increases the efficiency of metallurgical processes, the production of high-grade iron oxide pigments and iron ore briquettes, which increase the competitiveness of iron ore companies and the full use of the resource potential of deposits, are presented.
The article describes the role of geomechanics for forecasting the development of geosystems and ensuring the safety of mining operations during the transition to a new technological paradigm. The state and prospects of development of the mineral resource base, including the Arctic zone of the Russian Federation, are considered. The directions of technological breakthroughs and the possibility of transforming industrial production based on «cross-cutting» technology and the digital economy are presented. The analysis of geomechanical problems was carried out considering advanced technological changes and the rapid growth of requirements for the preservation of the Earth’s interior and natural landscapes. The concept of the development of geomechanics and geodynamics to ensure rational subsoil use in terms of the use of «breakthrough» technology is proposed, and the need to integrate scientific and industry collaboration into the system of engineering and professional education is shown.
In the aluminum industry, the largest amount of waste is red mud (RM). that is a solid bauxite residue after hydrochemical processing and extraction of alumina. The topicality of its processing was shown by the ecological catastrophe in Hungary (2010), where the bund wall of the slurry storage was destroyed and the viscous mass of fine red mud fell on thousands of hectares of land. The risks of a recurrence of such a catastrophe increase due to the increased natural disasters: earthquakes, torrential rains and floods, as well as terrorist attacks. Therefore, it is proposed to exclude the storage of red mud in sludge storages and organize its shipment in transportable form to processing complexes. The article presents the results of scientific research and the experience of complex processing of red sludge on an industrial scale with the production of new types of marketable products.
A problem of industrial fluxed agglomerates self-destruction in the process of cooling after sintering has been examined. It has been revealed that the main reason of strength degradation is polymorphism of dicalcium silicate Ca2SiO4 (or short designation С2S): β-Ca2SiO4 ® γ-Ca2SiO4. Ways for increasing the agglomerate strength by physical and crystal-chemical stabilization of the high temperature modification of C2S have been proposed and tested. Physical stabilization of C2S agglomerate is increased with its structure reinforcement due to thickening of walls between large pores that is achieved by increasing height of the sintered layer through improvement of its gas permeability. The task is addressed by substituting the previously used import sintering ore with the polydisperse ore from the Yakovlevo field, which improves the charge pelletizing by 3-4 times and helps to bring the height of the sintered layer and the strength of the domestic agglomerate up to the international best practice standards, while eliminating a need to purchase import high-vacuum exhausters. In practice crystal-chemical stabilization of C2S within iron-ore agglomerate is ensured by adding an opti- mal multicomponent additive in the form of the waste product generated in production of alumina from bauxites, i.e. the red mud, to the initial sinter charge. Thus mechanical strength of agglomerates and pellets is increased by 5-10 % and their hot strength improves by 20-40 %. The productivity of sintering machines and blast furnaces improves by 5-10 %. Specific coke consumption reduces by 2-2.5 %. In production of iron-ore pellets red mud is substituting the import bentonite.
The work reveals the ability of the Yakovlevskiy mine sinter ore to improve pelletizing of a sinter mix, to reduce its flow resistance in 4-5 times, to increase capacity of a sinter machine, to improve the sintering uniformity and sinter quality, to reduce consumption of agglomeration solid fuels and coke. Application of the Yakovlevskiy sinter ore moves sintering process to a modern technical level of charge in the sintering bed 500-600 mm in height without the use of expensive high-vacuum exhausters.
The way of precalculation downing and raisings of the wires suspended to support air Line of electric transfers, being in a zone of influence of mountain works is resulted. The technique of carrying out of monitoring high-voltage air Line of electric transfers is stated at it mines works.
The mine technical features of building of underground structures determining selection and parameters of ventilating systems and an air conditioning are reviewed, the engineering solutions on increase of control efficiency by quality of air are offered.
The non-tailing technology for processing of high grade iron ore Yakovlevsky deposit was created. The technology allows obtaining high-quality competitive product for iron and steel industry and in addition producing very high demand and competitive red iron oxide pigment. As the basis of beneficiation cycle, fine grinding of material with close circuit classification in hydrocyclones can be considered. To produce briquettes mixture of martite, hydro-hematite ores and non-pigment fraction, which is obtained in pigment cycle, are used. The ore is subjected to pre-screening. A coarse grain is used as final material for metallurgical processing. The fine grain is sent to the briquetting.
The analysis of soils stress-strain condition for different lining including in work period retards from tunnel’s face with applying of finite-elements method is adduced. The graphical relations of stresses, displacements, soils inelastic area configuration were obtained. According to these relations final graphical relation of temporary grouting influence for permanent lining stress-strain condition was developed.
Comparison of results of calculations of the tangential stresses on the inner contour of tunnel lining and radial stresses on the outer contour is done. Stresses are found by solving the problem of interaction in geomechanical system «lining-ground massif» in 2D and 3D model (single layer tunnel lining and double layer tunnel lining). Area of correct application of 2D models are revealed.
In this learned article the analysis of the volume stress-strain condition of the soils in the tunnel’s face in the cases of different repulses of support lining with applying of a finite-elements method is adduced. The graphic relations of stresses and displacements of the soils is developed and with respect to these relations the influence of the magnitude of repulse of support lining at the volume stress-strain condition of the soil massif is defined.
Briquetting in ferrous metallurgy is the earliest way clotting. In the beginning of XX century briquetting has been forced out by agglomeration basically for the reason considerably more productivity of process of agglomeration. As alternative to agglomeration pelletizing became. It started to be popular in the XX-th century, that is quite explainable by essential increase of manu- facture fine particle concentrates. However briquetting has a number of advantages. For some kinds of iron ores briquetting can be preferable process. Such ores are rich iron ores with iron content 60 % and more. The technology of briquetting includes crushing, preliminary screening for removing of large particle size classes; dispensing and mixing martite ore, and hydrohematite ores; mixing with binder substances; pressing; screening for removing of small size briquettes; drying. The received briquettes have density 3200-3600 kg/m3, durability on uniaxial compression more then 4,5 MPа.
Rich iron ores of the Jakovlevsky deposit are fine metallurgical raw materials. These ores are suitable for melt of high-quality metal at the minimum cost price as doesn't demand mineral processing. Ores contain a considerable quantity of fine classes particles and need briquetting. Mining operations include quality control of mined ore. The technology of briquetting includes, preliminary screening for removing of large classes; dispensing and preliminary mixing 85-90 % martite, iron-micaceousmartite ores and 10-15 % hydrohematite ores; mixing with connective substances; pressing; drying. The received briquettes have density 3200-3500 kg/m 3 , durability on compression 4,5 MPа.
The article deals with geomechanical and hydrogeological problems under the Yakovlevsky ore deposit development including variations in strength properties. The estimation of feasible underground water inrush inside the mining excavation is done. In situ results of ore strata deformation around excavation are discussed. Numerical modeling of stress and strain in the waterproofing ore pillar due to partially backfilling of excavation is carried out.
Изложен способ оценки геомеханического эффекта дополнительной активизации деформационного процесса в породном массиве и на земной поверхности при сооружении двух и более параллельных тоннелей на основе теоретических решений механики сплошной среды. Подобная количественная и качественная оценка этого эффекта при расчетах напряжений получила широкое распространение в механике подземных сооружений и других прикладных областях. В маркшейдерских расчетах сдвижений и деформаций традиционно используются преимущественно эмпирические подходы. Приведенные решения позволяют осуществлять такие оценки и учитывать подобные геомеханические эффекты в расчетах сдвижений и деформаций.
В статье предлагается расширить перечень параметров для оценки качества маркшейдерских геодезических сетей, добавив в него показатель топологической надежности сети. Рассмотрены оптимальные схемы высотных и плановых маркшейдерских геодезических построений, у которых показатель топологической надежности имеет максимально возможное значение, равное единице. Предложены формулы для подсчета количества измерений в таких построениях и даны рекомендации по обработке измерений в них.
Обоснованы критерии для оценки устойчивости обнажений выработок Яковлевского рудника и зависимости для расчета вертикальных и горизонтальных нагрузок на их крепь в рыхлых рудах, основанные на теории свода. Предложены типы и параметры крепей выработок рудного массива.
Field observations of the displacement of rocks around the preparatory and cleaning workings (operations) of SUBR mines (shafts) establish the effect of stratification of the roof of workings (operations) and cleaning chambers under the action of seismic waves. The shifts are traced to a depth of up to 4 m, and almost instantaneously, at the moment of the rock impact. When modeling the process of interaction of a flat straight wave with workings (production) of rectangular, vaulted and shapes of cross-section, it is shown that the probability of reaching the limit state of the host rocks due to the maximum difference in the main pressure (stress) is higher in workings (production) of rectangular and more shapes. Based on the revealed dynamics (changes) of seismic pressure (stress) and regularities of deformation of the host rocks, the design of reinforcement (strengthening) of the roof of chambers and joints of excavations (workings) with deep reinforced concrete anchors was developed.