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Date submitted2023-07-25
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Date accepted2024-05-02
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Date published2024-08-26
Finite element analysis of slope failure in Ouenza open-pit iron mine, NE Algeria: causes and lessons for stability control
Slope failures in mining engineering pose significant risks to slope stability control, necessitating a thorough investigation into their root causes. This paper focuses on a back analysis of a slope failure in the Zerga section of the Ouenza – Algeria open-pit iron mine. The primary objectives are to identify the causes of slope failure, propose preventive measures, and suggest techniques to enhance stability, thereby providing crucial insights for monitoring slope stability during mining operations. The study commenced with a reconstruction of the slopes in the affected zones, followed by a numerical analysis utilizing the Shear strength reduction method within the Finite element method (SSR-FE). This approach enables the examination of slope stability under both static and dynamic loads. The dynamic load assessment incorporated an evaluation of the vibrations induced by the blasting process during excavation, introducing seismic loading into the finite element analysis. The findings reveal that the primary triggering factor for the landslide was the vibration generated by the blasting process. Furthermore, the slope stability was found to be critically compromised under static loads, highlighting a failure to adhere to exploitation operation norms. The challenging geology, particularly the presence of marl layers where maximum shear strain occurs, contributed to the formation of the landslide surface. The study not only identifies the causes of slope failure but also provides valuable lessons for effective slope stability management in mining operations.
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Date submitted2023-04-10
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Date accepted2024-12-27
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Date published2024-04-25
Optimization of specific energy consumption for rock crushing by explosion at deposits with complex geological structure
The selection of efficient drilling and blasting technology to achieve the required particle size distribution of blasted rock mass and reduce ore dilution is directly related to the accurate definition of rock mass properties. The zoning of the rock massif by its hardness, drillability and blastability does not consider the variability of the geological structure of the block for blasting, resulting in an overestimated specific consumption of explosives. The decision of this task is particularly urgent for enterprises developing deposits with a high degree of variability of geological structure, for example, at alluvial deposits. Explosives overconsumption causes non-optimal granulometric composition of the blasted rock mass for the given conditions and mining technology. It is required to define physical and mechanical properties of rocks at deposits with complex geological structure at each block prepared for blasting. The correlation between the physical and mechanical properties of these rocks and drilling parameters should be used for calculation. The relation determined by the developed method was verified in industrial conditions, and the granulometric composition of the blasted rock mass was measured by an indirect method based on excavator productivity. The results demonstrated an increase in excavation productivity, thus indicating the accuracy of given approach to the task of identifying the rocks of the blasted block.
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Date submitted2021-07-05
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Date accepted2022-07-21
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Date published2022-11-10
Fragmentation analysis using digital image processing and empirical model (KuzRam): a comparative study
The rock fragmentation reflects the degree of control of blasting. Despite the accuracy of screening analysis to determine the size distribution of blasted rocks, this technique remains complex and long because of the large volume of blasted rocks. The digital image processing method can overcome these constraints of accuracy and speed. Our method uses the empirical model of KuzRam and numerical method (Digital image processing) through two image processing software’s (WipFrag and Split-Desktop) to analyze the particle size distribution of rocks fragmented by explosives in Jebel Medjounes limestone quarry. The digital image processing is based on the photography of the pile of blasted rock analyzed using image processing techniques. The objective of this work is to evaluate and compare the results obtained for each blast from the two methods and to discuss the similarities and differences among them. Three different blasts with the same design were analyzed through the two methods. The result of the KuzRam model gave idealistic results due to the heterogeneity of the structure of the rocks; although, this model can be used for an initial evaluation of blast design. For better efficiency of the explosion, we proposed a new fragmentation indicator factor in order to compare the fragment produced to the estimated ideal size obtained from the KuzRam model by incorporating the blast design parameters and the rock factor. Both image processing gives close results with more accuracy for the Split-Desktop software. Our method can improve the efficiency and reduce crushing costs of the studied career.
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Date submitted2021-07-13
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Date accepted2021-10-18
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Date published2021-12-16
Prediction of the stress state of the shotcreting support under repeated seismic load
- Authors:
- Maksim A. Karasev
- Roman O. Sotnikov
The article assesses the impact of repeated blasts on the stress-strain state of the shotcreting support, which negatively affects the bearing capacity of the support and can lead to the formation of local rock falls in places of significant degradation of the shotcreting strength. Despite the fact that a single seismic load usually does not have a significant impact on the technical condition of the shotcreting support, repeated dynamic loading can lead to the development of negative processes and affect the safety. The article considers unreinforced and dispersed-reinforced shotcreting concrete as a shotcreting support. Models of deformation of rock and shotcreting support have been studied. To describe the deformation model of a rock mass, an elastic–plastic model based on the Hook-Brown plasticity condition has been accepted, which accurately describes the elastic-plastic behavior of a fractured medium. When performing the prediction of the stress-strain state of the shotcreting support, a model of plastic deformation of concrete with the accumulation of Concrete Damage Plasticity (CDP) was adopted, which allows to comprehensively consider the process of concrete deformation both under conditions of uniaxial compression and stress, and with minor edging draft. At the first calculation stage, a forecast of the seismic waves propagation in the immediate vicinity of the explosive initiation site was made. At the second stage, forecasts of the seismic waves propagation to the mine working and the stress-strain state of the support were made. On the basis of the performed studies, a methodology for assessing the impact of repeated blasts on the stress-strain state of the shotcreting support of the mine working is proposed.
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Date submitted2020-06-15
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Date accepted2020-06-15
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Date published2020-06-30
Non-destructive testing of multilayer medium by the method of velocity of elastic waves hodograph
- Authors:
- Aleksandr I. Potapov
- Artem V. Kondratev
The method of velocity of elastic waves hodograph, aimed at non-destructive testing of structurally heterogeneous composite materials and products based on them, as well as multilayer products and constructions, is considered. The theoretical basis for determining the propagation velocity of elastic waves in a multilayer medium by the hodograph method is given. Based on the studies, recommendations are given for determining the propagation velocity of elastic waves in each individual layer of a multilayer medium, which allows non-destructive testing of the physicomechanical characteristics of each layer of a multilayer medium. It is shown that in addition to simple multiple reflections in a homogeneous medium, in a multilayer medium with parallel interfaces consisting of two or more layers, complex types of multiple reflected waves and mixed waves (reflected-refracted and refracted-reflected) can arise. The main task of applying the low-frequency ultrasonic method is to determine the acoustic parameters of the propagation of elastic waves (velocities, amplitudes, spectra). The main methods for determining the elastic wave velocities are considered, based on the hodograph equation of the indicated reflected waves in a multilayer medium.
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Date submitted2016-09-16
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Date accepted2016-11-12
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Date published2017-02-22
Possibilities of seismic exploration for crystalline basement study
- Authors:
- A. N. Telegin
Possibilities of seismic methods of reflected and refracted waves have been examined for the purposes of detailed study on crystalline basement structure. Investigation of depth and structure of the basement plays an important role in the exploration of various deposits. Sedimentary cover is usually associated with oil and gas reserves. Ore deposits are formed in the basement rocks, basement splits and structure of its surface have a genetic relation not only to ore minerals, but also to oil resources. Reflection seismology is one of the main seismic methods of investigating structural geometry of the sedimentation mass, forecasting its material composition and possible hydrocarbon reserves. However, its possibilities for investigating crystalline basement are limited. Basing on many years’ experience of reflection seismology and physical modeling it has been identified that actual roughness of basement surface limits the obtainable amount of waves reflected from it. Possibilities of reflection seismology for basement structure study are mostly related to investigation of discontinuous faults as diffraction objects using diffracted waves. Method of refracted waves combined with modern procedures and material processing aimed at getting dynamic seismic sections holds much significance for the basement study, especially in the process of surface mapping and, to a lesser extent, in investigating discontinuous faults.
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Date submitted2010-07-14
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Date accepted2010-09-29
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Date published2011-03-21
Basic requirements for shallow seismic field works technique by the reflected waves method for engineering-geological issues solving
- Authors:
- A. N. Telegin
- A. S. Yakovlev
The main requirements for the shallow seismic field works technique parameters for engineer-geological issues solving are represented. The optimum technique for the St.-Petersburg and its suburbs territory based on the results of experimental seismic studies, providing a detailed study of the upper part of the geological section, are proved.
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Date submitted2010-07-11
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Date accepted2010-09-14
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Date published2011-03-21
Application of seismic reflection method for engineering-geological issues solving in Saint Petersburg and Leningrad region
- Authors:
- A. S. Yakovlev
Several examples of seismic reflection method test surveys in St.-Petersburg and its suburbs are reviewed. The key point of research was the choice of an optimum field seismic works technique, processing and interpretation technique, providing the reliable solution of shallow depth investigation for the presented area.
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Date submitted2009-10-14
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Date accepted2009-12-28
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Date published2010-09-22
Geodynamic model of hydrogen sulphide’s formation in natural gas and oil in the process of rocks impulsive compression under conditions оf earthquakes
- Authors:
- A. V. Petukhov
By experiments, conducted on the installation like Bridgeman’s anvil it was determined that under conditions of high pressure, displacement deformations and elastic wave’s effect of short duration, sulphates are reclaimed by hydrocarbons. As a result of this reaction sulphur and hydrogen sulphide are produced.
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Date submitted2009-09-19
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Date accepted2009-11-24
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Date published2010-06-25
Distribution of the wave of vertical polarization in the infinite plasma layer with the maximum of the electronic concentration
- Authors:
- A. V. Denisov
The problem of dispersion of a flat wave of vertical polarisation by a plasma layer with a maximum of electronic concentration and infinitesimal losses is considered. With use of the theorem of an average in the new way it is proved that the wave of vertical polarisation will not pass for a point with the maximum of electronic concentration if loss in layer to direct to zero.
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Date submitted2009-09-07
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Date accepted2009-11-17
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Date published2010-06-25
The transformation of zone of potentially dangerous accumulative wrecks in a layeked mining roof when combined effect of the rock pressure and shock stress waves
- Authors:
- V. V. Karpenko
The transformation of potentially dangerous zone of wrecks accumulation in the layeredroof of the mining system is considered, in the time of combined action of geostatic pressure and tension shok wave. The explosion wave front is suggested to be parallel to the proximate handing roof environs discontinuity. Under this condition in the article is considered the influence of levels of critical stress and the depth of opening location on the change of implicitly dangerous zone of faults accumulation in the layers of the root stone.
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Date submitted2009-09-06
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Date accepted2009-11-14
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Date published2010-06-25
The estimation of mass velocities in a layered roof and dividing pillars of the mining system in the time of influence of shock stress waves
- Authors:
- V. V. Karpenko
- G. A. Kolton
The mass velocity diagrams transformation in the layered border zone of the mining system in the time of tension explosion waves influence is considered. The explosion wave front is suggested to be parallel to the proximate handing roof environs discontinuity. Under the admitted assumption the mass velocity epures transformation is investigated in the layered roof stone of the mining system and in the dividing pillar.
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Date submitted2009-08-23
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Date accepted2009-10-17
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Date published2010-02-01
Mathematical description of microwave contact level controller for liquid agent
- Authors:
- N. V. Teterin
- O. M. Bolshunova
It is shown the problem of measurement of level in oil tanks. Considered the use of a method of the sway electromagnetic radiation for the control of level of section of environments in tanks, made its mathematical description, resulted the estimation of results of practical application.