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Date submitted2024-05-28
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Date accepted2024-11-07
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Date published2024-12-25
Methods of intensification of pipeline transportation of hydraulic mixtures when backfilling mined-out spaces
The paper presents an analysis of the advantages and limitations of additional measures to intensify the transportation of the backfill hydraulic mixture flow. The results of the analysis of the conditions for using pumping equipment to move flows with different rheological properties are shown. Generalizations of the methods for influencing the internal resistance of backfill hydraulic mixtures by means of mechanical activation, as well as increasing fluidity due to the use of chemical additives are given. The article presents the results of studies confirming the feasibility of using pipes with polymer lining, which has proven its efficiency in pumping flows of hydraulic mixtures with different filler concentrations. An analytical model of hydraulic mixture movement in the pipeline of the stowage complex has been developed. The trends in pressure change required to ensure the movement of hydraulic mixture in pipelines of different diameters are exponential, provided that the flow properties are constant. The effect of particle size on the motion mode of the formed heterogeneous flow, as well as on the distribution of flow density over the cross-section, characterizing the stratification and change in the rheological properties of the backfill hydraulic mixture, is assessed. An analytical model of centralized migration of the dispersed phase of the hydraulic mixture flow is formulated, describing the effect of turbulent mixing of the flow on the behavior of solid particles. An assessment of the secondary dispersion of the solid fraction of the hydraulic mixture, which causes a change in the consistency of the flow, was performed. The studies of the influence of the coefficient of consistency of the flow revealed that overgrinding of the fractions of the filler of the hydraulic mixture contributes to an increase in the required pressure in the pipeline system.
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Date submitted2022-05-20
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Date accepted2023-04-03
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Date published2024-02-29
Impact of carbon dioxide on the main geotechnical quality criteria and preparation cost of cemented paste backfill
There is a global upsurge in the use of cemented paste backfill (CPB) for various mining functions. However, the cost of the Portland cement binder is prohibitive, thus warranting strategies to reduce cement usage without overly diminishing the CPB quality. Since carbon dioxide is used for patented sand moulding processes, this study is premised on that physicochemical ability of CO2 to enhance the curing of consolidated inorganic materials. It evaluated the impact of carbon dioxide on the uniaxial compressive strength UCS and preparation cost of CPB standard samples (ASTM C109). The preparation cost was delimited to the purchase cost of the Portland cement. The backfill material was silica sand tailings with 4.5 wt.% Portland cement binder and a water-cement ratio of 7.6. Distilled water of pH 5.4 was used for the control samples while variable amounts of carbon dioxide were dissolved in distilled water to generate carbonated mixing water with pH values of 3.8; 4 and 4.2. The lower the carbonated water pH, the higher is the CO2 concentration. UCS tests were conducted on the samples after curing for 3, 7, 28, and 90 days. There was an observable increase in the UCSs and reduction in curing time with increasing carbon dioxide. Samples prepared with carbonated water of pH 3.8 had almost double the strength of those prepared with pure distilled water of pH 5.4, implying that more dissolved CO2 corresponds to higher CPB strength. This is supported by the trendline equations for the graphical simulation of strength on curing time. Thus, CPB with much less binder can be expected to attain the requisite UCS if carbon dioxide is incorporated. The average reduction in Portland cement consumption was 0.61 %, which translates to a cost saving of the same percentage points. If calculated over the operational life of a mine, this is a massive saving of millions of dollars.
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Date submitted2022-10-17
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Date accepted2023-02-13
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Date published2023-04-25
Environmental geotechnology for low-grade ore mining with the creation of conditions for the concurrent disposal of mining waste
Due to the constantly deteriorating environmental situation in the regions with mining enterprises, the article considers the topical issue of disposing the maximum possible volume of waste from the mining and processing of low-grade ferrous ores through the creation of an effective underground environmental geotechnology. Traditional procedure with descending mining of reserves with a caving system does not allow waste to be disposed of in a gob. The idea is to use geotechnology based on the ascending order of mining the ore body, room excavation, leaving truncated pillars, and staggered arrangement of adjacent rooms in height, which makes it possible to form containers for waste disposal in the form of a cementless backfill. The main characteristics of the proposed procedure are investigated and compared with the traditional procedure of low-grade iron ores mining. It was established that from the point of view of the complete extraction of reserves and the unit costs for the preparatory-development operations, the processes are comparable, while in terms of the mining quality, the proposed option is much more efficient. Evaluation of environmental geotechnology by the criterion of waste disposal, performed according to the proposed methodology, showed that the combination of these technical solutions ensures the placement in the formed gob from 80 to 140% of all waste generated during the mining and beneficiation of low-grade iron ores.
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Date submitted2021-04-19
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Date accepted2022-05-25
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Date published2022-07-13
Development of the technology of stowing the developed space during mining
- Authors:
- Evgenii R. Kovalskii
- Kirill V. Gromtsev
An analysis of the world experience in the development of potash deposits shows that the main problems arising during their development are a high level of mineral losses, an increased risk of flooding of mine workings as a result of water-proof layer discontinuance and the development of emergency water inflows in the mined-out spaces. Reduction of potash ore losses can be achieved by using a long-pillar mining system, but this method is limited by the peculiarities of the geological structure of the potash deposits and the need to preserve the continuity of the water-proof layer during its underworking. The safety of underworking of the water-proof layer can be improved by using the stowing of the developed longwall space. However, the question of the influence of the stowing on the height of the zone of water supply cracks development remains little-studied. The world experience of stowing the developed spaces in the development of layers with long pillars is analyzed and the technology of placing the stowing masses, which can solve these problems, is proposed. The considered technology and the proposed solutions are supported by laboratory tests of stowing materials and mathematical modeling of deformation zones in the overlying rocks.
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Date submitted2013-07-20
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Date accepted2013-09-20
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Date published2014-03-17
Interchamber pillars partial working off technology at the floor-and-chamber system of development of the Korobkovsky deposit of KMA
- Authors:
- E. I. Boguslavskii
- M. N. Andreev
Article is devoted to a choice of rational technology of mining of part of stocks interchamber pillars at floor-and-chamber system of development of the Korobkovsky deposit of KMA. Authors carried out calculations and comparison of technical and economic parameters of two offered technologies of mining: horizontal layers with a stowing in an ascending order with application of a portable equipment and horizontal layers with a stowing in an ascending order with a driving of autobiases in interpanel pillars. For a choice of method of development for mining of part of interchamber pillar and determination of its parameters and indicators.
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Date submitted2013-07-16
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Date accepted2013-09-16
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Date published2014-03-17
Stopes walls stabilization at the rich iron ore mining by the flat-back cut-and-fill method
- Authors:
- V. P. Zubov
- M. D. Morozov
- A. S. Malyutin
The most influencing the stopes walls stability factors have been determined. Physical-and-mechanical ore mass properties impact to the stopes height has been researched. Advanced ways to improve stopes walls stability have been considered.
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Date submitted2013-07-05
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Date accepted2013-09-16
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Date published2014-03-17
Prospects of improving technology for development of coalseams in Vietnam’s undergroundmines
- Authors:
- Kao Kuok Vet
- V. P. Zubov
In the article the problem associated with the necessity of application of the full goaf stowing technology in developing the steep coal seams in terms of Mao Khe deposit in Vietnam is presented.
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Date submitted2009-07-08
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Date accepted2009-09-19
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Date published2010-04-22
Geomechanical and hydrogeological problems оf the Yakovlevsky deposit development
- Authors:
- V. L. Trushko
- A. G. Protosenya
- R. E. Dashko
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.
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Date submitted2008-11-01
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Date accepted2009-01-27
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Date published2009-12-11
The influence of the technological and organizational factors on the steady growth of the mining industry
- Authors:
- E. M. Pronin
- V. E. Vasiliev
The steady growth of the mining industry calls forth the character of its activities connected with the dependence of the work on the natural conditions which are practically unpredictable and constantly changeable. The two basic factors are chosen – the technology of the mining work and the organization of the industry, which have the decisive importance in the increasing of the basic indices of the activity of the enterprise. The possible technological and organizational solutions are offered as they permit to find possible directions in the lowering of the negative influence of the appearing problems.