-
Date submitted2023-07-25
-
Date accepted2024-05-02
-
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.
-
Date submitted2022-01-20
-
Date accepted2022-07-21
-
Date published2023-12-25
Tribodynamic aspects of the resource of electric submersible vane pumps for oil production
The operation of electric submersible vane pumps for oil production is accompanied by the presence of solid particles, corrosive substances, asphalt-resin-paraffin deposits in the reservoir fluid, leading to changes in performance characteristics and equipment failures. The reduction of the resource as a result of this is accompanied by an increase in the costs of repair and replacement of equipment. The main processes that negatively affect the failure are the wear of the seals of the working stages, the pump plain bearings and vibration, the level of which can significantly exceed the initial level. A test bench and methodology for testing pump sections for wear in water with an abrasive and simultaneous registration of vibration characteristics have been developed. Two main forms of wear of radial seals have been identified – one-sided and equal-dimensional. The one-sided form of sleeve wear is caused by synchronous shaft precession, whereas the equal-dimensional one is an asynchronous precession, and the vibration level increases with increasing wear. The wear distribution of radial seals along the length of the pump correlates with the shape of the elastic shaft line. The wear of the axial seals does not significantly increase the vibration level. During wear the frequency spectrum of vibrations changes; there occurs a frequency that can serve as a diagnostic sign of ultimate wear of the pump. The calculated dependence of the vibration velocity on the wear of the radial seals of the working stages is obtained, which makes it possible to predict the onset of a failure of functioning.
-
Date submitted2021-09-22
-
Date accepted2021-11-30
-
Date published2021-12-27
Possibilities for creating Russian high-tech bottomhole assembly
Development of high-tech well electronic measuring systems is aimed at creating modern equipment: telemetry, well geophysical measurement equipment, the architecture of which is divided into basic (with measurement channels for gamma logging and inductive resistance) and advanced (with radioactive, acoustic, magnetic resonance and thermobarometric measurement channels, including azimuthal methods of investigation). Over-the-bit measurement modules, rotary steerable systems are being developed and channels for transmitting data to the surface are being improved. Vice versa, specialized surface equipment with highly integrated software is being created. Different measurement modules are manufactured by different companies, which creates uncertainties in the possibility of interfacing the manufacturers' measurement modules into a single well measurement system. The article presents an analysis of the readiness of Russian oil service companies to produce well and surface equipment for drilling Russian directional oil and gas wells, meeting modern requirements for accuracy, lifetime and operating conditions. The possibility of creating a fully Russian well high-tech equipment and the required resources, risks and measures to mitigate them when creating a modern well measurement system are considered.
-
Date submitted2020-05-15
-
Date accepted2020-06-12
-
Date published2021-06-24
One of the ways to increase the durability of the sectional pump balancing ring
- Authors:
- Nikolai P. Ovchinnikov
The article presents the results of scientific research aimed at struggling the adhesive wear of parts of sectional pumps balancing ring, where the drainage units pumping equipment of the Russian Federation underground kimberlite mines was used as an object of research. It has been theoretically proven and experimentally confirmed that if there is data on the total operating time of a sectional pump in transient modes per day, using the constructed regression model, it is possible to calculate with high accuracy the average operating time of its balancing ring unit to failure. The constructed regression model is applicable only to sectional pumps of drainage units of underground kimberlite mines in the Russian Federation. It is possible to increase the durability of the balancing ring by reducing the acceleration and deceleration time of the sectional pump; for safe operation, it should be at least 10 s. Pilot tests carried out indicate the effectiveness of the proposed method for prompt identification of the critical axial displacement of the sectional pump rotor through the vibration of the discharge tube. The introduction of this method will reduce the cost of repair work to restore the performance of parts of the hydraulic foot to a minimum.
-
Date submitted2019-10-30
-
Date accepted2019-11-23
-
Date published2020-02-25
Methodology for determining the parameters of drilling mode for directional straight sections of well using screw downhole motors
- Authors:
- Vladimir S. Litvinenko
- M. V. Dvoinikov
Article presents results of study on possibility of increasing the efficiency of drilling directional straight sections of wells using screw downhole motors (SDM) with a combined method of drilling with rotation of drilling string (DS). Goal is to ensure steady-state operation of SDM with simultaneous rotation of DS by reducing the amplitude of oscillations with adjusting the parameters of drilling mode on the basis of mathematical modeling for SDM – DS system. Results of experimental study on determination of extrema distribution of lateral and axial oscillations of SDM frame depending on geometrical parameters of gerotor mechanism and modes ensuring stable operation are presented. Approaches to development of a mathematical model and methodology are conceptually outlined that allow determining the range of self-oscillations for SDM – DS system and boundaries of rotational and translational wave perturbations for a heterogeneous rod with an installed SDM at drilling directional straight sections of well. This mathematical model of SDM – DS system's dynamics makes it possible to predict optimal parameters of directional drilling mode that ensure stable operation of borehole assembly.
-
Date submitted2018-09-04
-
Date accepted2018-11-18
-
Date published2019-02-22
Operation experience of centrifugal single-stage pumps in «ALROSA» Joint Stock Company
- Authors:
- N. P. Ovchinnikov
When mining diamond-bearing raw materials and further extracting diamonds from it in the joint-stock company ALROSA, which is a city-forming enterprise in the north-east of the Russian Federation, various pumping equipment is used, in particular, centrifugal single-stage pumps. In the present work, it is noted that the least reliable in terms of absence of failures of centrifugal single-stage pumps used in the joint-stock company ALROSA are the impellers, seals and bearing assemblies. Using linear correlation and regression analysis, it was found that the durability of the seals and bearing assemblies of the investigated pumps largely depends on the durability of their impellers. In the course of research, it was found that unbalancing the pump rotor due to excessive hydroabrasive wear of the impeller also leads to deformation and fracture of the shaft. In general, residual deformations and destructions are characteristic of the shafts of domestic pulp pumps of GrAT, GrT and Gr types. The most loaded sections of shafts of centrifugal single-stage pumps are installed. The most effective from the point of view of application among the pulp (ground, slurry and sand) pumps are pulp pumps of the Finnish company «Metso». When working on highly mineralized water (brines), the «X» type pumps have proven to be the best among centrifugal single-stage pumps.
-
Date submitted2016-09-01
-
Date accepted2016-11-05
-
Date published2017-02-22
Research on technical and technological parameters of inclined drilling
- Authors:
- M. V. Dvoinikov
An analysis of operational capabilities of inclined drilling equipment and technology is presented. Two options of rotary drilling are reviewed as technical and technological solutions, facilitating construction of wells with difficult profiles. The first option implies that the driver unit of the drill bit is represented by downhole drilling motor, the second one utilizes sophisticated rotary steerable systems. Practical results of drilling wells with difficult profiles are presented. A quality assessment of drilling is provided through the example of comparing designed and actual trajectories, using different driver units for the drill bit, as well as properties of surrounding rocks, rheology of the drill fluid and other characteristics of dynamically active systems. A range of rotation speed has been determined that allows rotary steerable systems to have minimal oscillation amplitude of the bottom-hole assembly. Analysis of investigation results showed that the main source of oscillations is linked to bending and compressing stresses, caused by well deviations as well as rigidity of the drilling tool. In effect, in the bottom-hole assembly occur auto-oscillations, making it impossible to correct azimuth and zenith angles. Alteration of rigidity in the bottom part of the tool and drilling parameters, implying reduced rotation speed of the drill string and regulation of drill bit pressure, can partially solve this problem, though increase in rotation speed is limited by technical characteristics of existing top drive systems.
-
Date submitted2015-10-06
-
Date accepted2015-12-18
-
Date published2016-08-22
New technology of dry benefication of fly ash from coal power plants using applied mineralogy techniques
- Authors:
- V. A. Arsentev
- E. L. Kotova
The existence of environmental and strategic need to process dumps and slagheaps of coal mining enterprises of Russia and foreign countries results in reviewing the potential of using fly ash as a technogenic mineral resource. Comprehensive studies of substance composition of fly ash from coal power plants make it possible to define rational further ways of utilizing that mineral resource substantiating the scheme of its technological secondary processing. In view of the numerous environmental problems stemming from the techniques of wet benefication and processing of that mineral resource, a technology is suggested of dry cleaning of fly ash from thermal coal power plants. Studies were carried out using a number of samples of fly ash from various power plants. The suggested criteria are used to discriminate the compounds of fly ash and quantitative and qualitative composition of particulate matter is assessed. Studies of substance composition of fly ash samples has demonstrated that the concentration of non-combusted carbon in them varies from 5 to 20 %. The principal technological procedure of cleansing in our studies was a combination of magnetic and electric separation of ash in the state of vibrational pseudo-liquefaction. It enables one to increase the throughput capacity and selectivity of the cleansing process significantly. In the result of such cleansing a stable mineral fraction is produced that contains 0.5-2.5 % of carbon, so that the purified mineral fraction can be used as a construction binding agent.
-
Date submitted2015-08-03
-
Date accepted2015-10-06
-
Date published2016-04-22
Technical and technological solutions to ensure stability of downhole drilling motors
- Authors:
- M. V. Dvoinikov
- Yu. D. Muraev
The article shows research analysis of engineering and technological solutions that aimed at improving the efficiency of drilling wells using optimization of dynamic of work downhole drill-ing motors. As the technical solutions that reduce vibration, considered two options of construc-tion of the power section. A first embodiment involves the production of a hollow rotor which can reduce its moment of inertia. The second solution is the production of modular rotor, which are changing the eccentricity (misalignment) of rotating parts of the engine. The research of fluctuations throughout the length of the power section of the working bodies and the spindle of the engine, taking into account changes in its energy characteristics has been con-ducted to ensure stable operation of the engine in a well, identifying optimal loading parameters. Indicators of shaft speed ensuring minimum vibration amplitude of the engine has been Iden-tified. Optimal speed range of the rotor to prevent buckling of the BHA and to sustain its operation is shown to be between 15-20 % of the frequency of the engine at idle. The maximum reduction in speed during the drilling process should not exceed 30 % by conducted research.
-
Date submitted2014-10-09
-
Date accepted2014-12-26
-
Date published2015-08-25
Improving the precision of manufacturing power hydraulic cylinders of powered roof supports based on a vibration-damping tooling system
- Authors:
- V. V. Maksarov
- Yu. Olt
The article deals with a new system of a vibration-damping tool, the effect of which is achieved by a combination of the multi-layer principle and the use of anisotropic properties of sheet metal. Operation of such tool systems in turning operations can reduce high-frequency vibra-tions arising in the process of cutting due to the ordered disorientation of anisotropic plate texture of a multilayer modular tool holder that allows you to efficiently dissipate oscillatory wave energy at the boundary of transition between the plates of the tool holder. This method allows increasing the resistance of the tool cutting edge significantly and expanding the technological capabilities for the effective selection of cutting modes to ensure compliance with requirements for dimensional and geometric accuracy, quality of processed surfaces of powered roof supports, hydraulic units, mining machinery and equipment.
-
Date submitted2010-07-15
-
Date accepted2010-09-13
-
Date published2011-03-21
Experimental setup for research Influence of vibromechanical treatment on mechanical properties of welded joints
- Authors:
- O. F. Khafizova
- V. I. Bolobov
The description of developed experimental setup for welding product that made of pipeline steels with application of applying vibration with intended frequency approximating to natural-vibration frequency of welded construction unit of pipelines during the welding cycle is presented.
-
Date submitted2009-08-05
-
Date accepted2009-10-21
-
Date published2010-02-01
The autoresonant electric drive of the swinging movement pendular vibration exciter vibration jaw crushers
- Authors:
- Yu. A. Gavrilov
- E. A. Zagrivnyi
To use of the autoresonant electric drive of swinging movement for creation of an oscillative motion of crushing jaws of vibrating jaw crushers it is offered in this article. The control system of the electric drive is developed. The results of imitating and physical modelling of the autoresonant electric drive are presented.
-
Date submitted2009-08-16
-
Date accepted2009-10-16
-
Date published2010-02-01
Experimental determination of vibration jaw crusher perfomance and characteristic of the crusher two-motor drive in no-load and nominal mode of operation
- Authors:
- S. Yu. Tyagushev
- O. B. Shonin
The paper is devoted to the experimental study of jaw crusher characteristics under condition that nonidentity of subsystems electro-mechanical parameters causes the distortion of the nominal mode of the jaw crusher operation. Experimental data obtained have confirmed basic statements of a self-synchronization theory. The initial phase shift of jaws oscillations is shown to result in a substantial decrease in the crusher productivity and a significant increase in the specific power consumption.