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Date submitted2024-04-22
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Date accepted2024-06-13
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Date published2024-07-04
Lithification of leachate from municipal solid waste landfills with blast furnace slag
- Authors:
- Mariya A. Pashkevich
- Yuliya A. Kulikova
The article presents an alternative method of utilization of blast furnace slag and leachate from solid municipal waste landfills, the formation of which occurs during the infiltration of atmospheric precipitation through the thickness of deposited waste. The method is based on the conversion of leachate from the liquid phase to the solid aggregate state by lithification using blast furnace slag as an astringent material. The hydraulic activity of slag, which depends on the amount of oxides contained in it, has been estimated. The investigated slag belongs to the 3rd grade, which confirms the possibility of its use as an astringent material. The filtrate was analyzed for the content of various elements, and the maximum permissible concentrations for each element were found to be exceeded. Chemical and biological oxygen demand were determined, and critically high values were installed (17200 mgO2/l and 4750 mgO2/l, respectively). The lithification process was divided into two stages. The first stage was to reduce the organic component in the filtrate using a coagulant, aluminum sulfate; the second stage was slag hydration. The optimum ratio of lithificate components in terms of mixture solidification rate was established at 1:0.03:1.25 (leachate, coagulant, blast furnace slag). The obtained material was analyzed for the solubility and content of various forms of metal. It is established that at infiltration of atmospheric precipitations through lithificate only 3 % of material will be washed out; concentrations of gross and mobile forms of heavy metals do not exceed the maximum permissible, except for the gross content of arsenic, mobile, and water-soluble forms of which were not found. The values of chemical (687 mgO2/l) and biological (173 mgO2/l) oxygen demand in the aqueous extract from lithificate decreased more than 25 times in comparison with the initial filtrate. According to the results of toxicological studies, lithificate was assigned an IV class of waste hazard, which confirms the possibility of its use as bulk material at landfills.
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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 submitted2020-06-16
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Date accepted2021-03-29
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Date published2021-09-20
Empirical regularities investigation of rock mass discharge by explosion on the free surface of a pit bench
- Authors:
- Igor A. Alenichev
- Ruslan A. Rakhmanov
Minimizing the discharge of blasted rock mass into the developed space of the pit is a very relevant area for study, as it allows to increase the processability of work and reduce the cost of mining. The article presents the results of experimental industrial explosions, during which the study of this issue was conducted. The main purpose of the work was to establish the key factors affecting the volume of rock mass discharge to the pit haulage berm. During the analysis of the world experience of research on this topic, the key factors affecting the formation of collapse and discharge – natural and technological – are identified. The method of conducting experiments and collecting data for analyzing the influence of technological parameters of location, charging and initiation of wells on the volume of rock mass discharge is described. It is established that the main discharge to the pit haulage berm is formed by the volume of rock mass limited by the prism of the slope angle. With a sufficient rock mass displacement from the edge of the bench crest towards the center of the block, only the wells of the 1st and 2nd rows participate in the discharge formation. Empirical dependences of the total volume of rock mass discharge on the length of the block along the bench crest, the specific consumption of explosives, the size of a rock piece P 50 and the rate of rock breaking are obtained. The obtained results can be used to design the parameters of the drilling and blasting operations (DBO), as well as to predict and evaluate the possible consequences of a mass explosion in similar mining and geological conditions.
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Date submitted2021-01-25
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Date accepted2021-02-22
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Date published2021-04-26
Conducting industrial explosions near gas pipelines
The problem to ensure the safety of objects which are in the area of blasting operations, ensuring the destruction of hard rocks, remains relevant. The article presents the results of a large-scale experiment to determine the safe conditions for conducting drilling and blasting operations near the active gas pipeline. The simplest and most reliable way to ensure the safety of the protected object from seismic impact is to reduce the intensity of the seismic wave, which is achieved by changing the parameters of drilling and blasting operations. This requires research to determine the impact of blasting operations on the parameters of seismic waves and the development of methods for measuring these parameters. The paper presents a detailed analysis of the seismic blast wave impact on the displacement of the ground and the model gas pipeline. The features of seismic monitoring during blasting operations near the active gas pipeline are shown. The seismic coefficients and attenuation coefficient of seismic waves are determined. It is proved that the readings of the seismic receivers on the surface and in the depth of the massive differ by two or more times.
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Date submitted2020-05-13
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Date accepted2020-11-12
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Date published2020-12-29
Improving the efficiency of terrigenous oil-saturated reservoir development by the system of oriented selective slotted channels
A comparative assessment of variation in the flow rate of oil production wells was performed taking into account increasing of perforated area of the productive part of the rocks, as well as recover of reservoir rocks permeability due to their unloading by creating slotted channels with the method of oriented slotted hydro-sandblast perforation. Different orientation directions and slotting intervals were analyzed, taking into account water encroachment of individual interlayers and azimuth direction of the majority of remaining reserves in separate blocks of the examined formation. In order to estimate development efficiency of terrigenous oil-saturated porous-type reservoirs by means of oriented slotted hydro-sandblast perforation, calculations were performed on a full-scale geological and hydrodynamic model of an oil field in the Perm Region. The object of modeling was a Visean terrigenous productive forma tion. The modeling of implementing oriented slotted hydro-sandblast perforation was carried out on a 3D filtration model for fourteen marginal wells, located in the zone with excessive density of remaining recoverable reserves and he terogeneous reserve recovery along the section. An optimal layout of slotted channels along the depth of the productive part of the well section was developed. Selective formation of 24 slotted channels was carried out con sidering the intervals of increased oil saturation. Comparative analysis of estimated flow rate of the wells was per formed for cumulative perforation of the examined productive formation and the developed method of slotted perforation. As a result of modeling, an increase in the oil average flow rate of 2.25 t/day was obtained. With oriented slotted hydro-sandblast perforation, incremental cumulative production for two years of prediction calculations per one well reached 0.5 thousand t.
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Date submitted2020-06-16
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Date accepted2020-07-13
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Date published2020-11-24
Study of Aluminum Influence on the Adhesion of Stainless Steel in Flame Spraying
This paper is dedicated to a study of aluminum influence on the improvement of surface adhesion strength. The main purpose of this work is to investigate the strength of adhesion to the substrate by mixing flame spray powder with aluminum, which not only possesses high corrosion resistance and conductivity, but also provides additional strength, as it combines and reacts with other components of the powder. Research results of sandblasting dependence on surface roughness parameter Ra are demonstrated. The paper describes authors’ original device for a measuring instrument “Profilometer”, which was also used for measuring roughness parameter in order to obtain comparative results. Authors present results of adhesion measurements given obtained values of surface roughness by mixing nominal chemical composition of PR-30X13 powder, used as a testing material, with aluminum, which reacts with oxides on the surface of steel substrates, imparts strength to the bonding between the coating and the substrate, protects the base metal due to a combination of chemical components of the powder and creates a layer of dense surface coating. These dependencies are analyzed and parameters, exerting the greatest influence on their values, are identified. Taking into account the results obtained through numerical modeling, authors propose a mathematical model of a dependency between adhesion strength and certain values of surface roughness for different chemical compositions of flame spray powder. These studies will help in the development of certain material types for spraying and hardening of steel parts and products in order to improve their durability.
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Date submitted2020-05-24
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Date accepted2020-07-23
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Date published2020-11-24
Estimation of ore contour movements after the blast using the BMM system
Measurement of ore movements by blast is one of the key components of the quality control system at any mining enterprise, which allows to obtain the accuracy necessary for determining the location of ore contours. About 15 years ago, a monitoring system was developed in Australia that allows mine personnel to make three-dimensional measurements of ore blocks movement at each blast. Studies have shown that ore blocks movement is extremely variable, and it characterized by a complete absence of a deterministic component. The consequence is that modeling ore contour movements during the blast will be inaccurate, and the best results for the mining enterprise can only be achieved by directly measuring the movement. The technology of measuring ore contours movements considered in the article is based on three-dimensional movement vectors obtained in different parts of the blasted block, characterized by different movements. It is obvious that the accuracy of determining the ore contours position after the blast is proportional to the number of measurements made on the block. Currently, the movement control technology based on the BMM system is actively used by global mining companies, its use reduces losses and dilution of ore. In 2017, the pilot implementation of the BMM system was started at the Olympiadinsky GOK, and the system is being implemented in several Russian mining companies.
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Date submitted2018-12-25
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Date accepted2019-03-22
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Date published2019-06-25
Technology of blasting of strong valuable ores with ring borehole pattern
- Authors:
- I. V. Sokolov
- A. A. Smirnov
- A. A. Rozhkov
The ores of non-ferrous and precious metals, represented by hard rocks, has a peculiar feature, that is the effect of segregation, that is the tendency of ore minerals to break down into small size classes, which in the underground mining method accumulate in significant quantities on uneven surface of bottom layers and subsequently are lost. When mining valuable non-metallic materials, there is an acute problem of overgrinding, when fines do not meet the requirements for the quality of the final product. It is well known that the granulometric composition of the ore depends mainly on the technology and parameters of drilling and blasting operations. In underground mining of ore deposits, the main method of drilling and blasting is the borehole blasting with continuous construction charges with the ring pattern. The main drawbacks of the method are: uneven distribution of the explosive along the plane of the broken layer and the expenditure of a significant part of the blast energy of the charges of the continuous structure on the blasting effect, necessarily associated with over-grinding the ore. To solve these problems, the authors proposed a blasting technology, the essence of which lies in the fact that the uniform distribution of the energy concentration of explosives in the broken layer is ensured by the dispersion of charges by air gaps and a certain order of their placement in the ring plane. For the practical implementation of the technology, a method has been developed to form dispersed charges in deep boreholes that do not require a significant increase in labor costs and additional special means. A special technique has been created that allows defining the dispersion parameters, ensuring the sustained specific consumption of explosives over the entire plane of the broken layer. Experimental studies of the proposed technology in the natural conditions of an underground mine for the extraction of valuable granulated quartz were carried out. As a result, the possibility of a significant reduction in the specific consumption of explosives (by 42 %) has been established. At the same time, the yield of the commercial product increased by 10.7 % in total, and the yield of the fraction most favorable for further processing increased by 33.7 %.
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Date submitted2017-09-20
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Date accepted2017-10-29
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Date published2018-02-22
Substantiation of strength of the filling mass by taking a blast effect into account for the room-and-pillar methods
- Authors:
- E. T. Voronov
- V. N. Tyupin
The development of the uranium ore bodies at the ore mines of PJSC «Priargunsky Industrial Mining and Chemical Union» (PJSC «PIMCU») by room-and-pillar method as high as a pillar between the levels (60 m) without fill, as a rule, leads to the fall of the adjoining rock, to the strong contamination of the ore and to the high yield of the oversize pieces of the barren rock. A longstanding industrial and theoretical research shows that the sizes of the self-sustaining rock escarpments at the ore mines of PJSC «PIMCU» in the solid mass of trachydacites, conglomerates, sandstones, felsites are equal to 20-40 m. Moreover, the sizes of the self-sustaining rock escarpments depend to a great extent on the intensity of fracturing of the adjoining rocks. The stable size of the escarpment does not exceed 5-10 m for the rocks with the size of a jointing up to 0.05 m. Consequently, timely performance of the filling operations of the worked-out space of the chamber is important. However, the question then arises: which characteristic strength should the filling mass have? The calculations of the characteristics of the filling mass in compliance with the reference guide «Shaft filling operations» show underestimated values of the characteristic compressive strength of the fill (1.4 MPa) for the room-and-pillar method, which leads to the increase of the ore contamination by the fill and provokes the additional costs for refilling of the volumes of the rock fall. On the basis of the Russian experience of using of the consolidated fill for the development of the ore bodies of 15 m thickness by chamber method the strength of the fill is taken as 3-5 MPa under the resultant value of the static stresses without taking into account the character of the dynamic loading stresses induced by the sequence blasthole ring initiating in a chamber. Overestimating the characteristic strength of the filling mass results in the high consumption of the cementing materials. On the basis of the theoretical research the authors suggested the theoretical dependence of calculation of the characteristic strength of the filling material with respect to compressive stresses of the fill induced by the blasting operations. The process of designing of the filling mass with the zones of diverse strength for the room-and-pillar extraction with the consolidated rock fill is proven to be economically reasonable. The bottom zone of the solid mass should have high strength (3-4 MPa), and the strength of the upper zone should be up to 2-2.5 MPa.
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Date submitted2015-10-17
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Date accepted2015-12-19
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Date published2016-08-22
Improving the retention of minerals in the course of separating monolith from bedrock with the use of gas generator cartridges
- Authors:
- G. P. Paramonov
- V. N. Kovalevskii
- Peter Mozer
Results are presented on the effect of firing rate on pressure pulse in charge camera and fracture stress during spalling. Results are presented of comparative calculations using the equations of autocatalytic reactions of firing rates and escape of reaction products for the system of sodium chlorate - polythene (propylene) in pipe shape. Dependences are obtained of firing rate on concentration of gas generating mixture, its density, components size distribution and cartridge case size. Experimental and computational data were used to consider the conditions of firing turning into explosion for compositions based on sodium chlorate and hydrocarbons in layered and powdered systems. The relation is retrieved between the technological parameters of mining activities (blast hole to blast hole distance, blast hole diameter, depth of cartridge placement) and specific cartridge consumption along the spalling line with gas generators going off.
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Date submitted2014-11-10
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Date accepted2015-01-28
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Date published2015-10-26
Study of technological properties of the yakovlevskiy mine sintering ore
- Authors:
- V. L. Trushko
- V. A. Utkov
- A. S. Klyamko
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.
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Date submitted2009-10-26
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Date accepted2009-12-27
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Date published2010-09-22
Support of geodynamic safety in mining of the Khibini deposits
The paper deals with the problems of geodynamics in mining of the Khibini deposits. Description is given to the complex of organizational-technical arrangements for provision of geodynamic safety at the Apatit Co and to principal trends of its development.