scholarly journals Planetary fracturing and lineaments revealed in the Kovdor magnetite–apatite ore deposit by open pit mining

2020 ◽  
pp. 30-34
Author(s):  
I. B. Agarkov ◽  
◽  
I. M. Ignatenko ◽  
V. A. Dunaev ◽  
I. S. Kryuchkov ◽  
...  

The analysis of the studies into fracturing of Zhelezny pitwall rock mass over the period from 1989 to 2019 proves that planetary fracturing is represented by faults, carbonatite dykes and single fractures oriented in the same direction as the prevailing regional lineaments on the Kola Peninsula. Planetary fracturing is assumed as a system of regular-oriented fractures. The planetary fracturing also includes lineaments of tectonic origin. The scientists think the faults registered in the pitwall rock mass and codirectional with the lineaments will accompany mining operations down to the full depth of the pit, up to the full extraction of magnetite–apatite ore reserves. While preparing this article, the authors have collected, generalized and analyzed the data of geological and structural mapping implemented by VIOGEM’s experts over the period from 1989 to 2019. VIOGEM’s procedure of geological and structural mapping ensures continuous documentation of extensional tectonics at high referencing accuracy (to 50 cm), as well as determination of inaccessible azimuths and angles of fractures by remote assessment of their orientations in pit walls using a laser scanner and photographic techniques to study the structure of hard rock mass and the behavior of permanent benches.

2021 ◽  
Vol 6 (1) ◽  
pp. 31-41
Author(s):  
I. K. Chunuev ◽  
Yu. M. Levkin ◽  
Zh. Bolotbekov

Mine surveying in mining operations is of particular importance, since all technological processes of the full life cycle of a mining enterprise and, ultimately, its competitiveness depend on the surveying quality, efficiency and reliability. Organizations independently determine the structure of mine surveying services, taking into account the methods applied and the scale of mining. To ensure safe open-pit mining of minerals, it is necessary to permanently assess and monitor the pit bench and wall rock mass condition. Misjudgement of rock physical and mechanical properties, non-observance of the minerals mining and transportation process cycle, changes in climatic conditions and other problems lead to loss of stability of rocks in all parts of an open pit, including in the areas of ore production and mining and transport equipment operation. The existing practice shows that the effectiveness of an open pit wall and bench stability calculation can be achieved using a technique that should take into account the slope deformation and failure mechanism, as well as the nature of the stress-strain state of the open pit rock mass. The studies presented in the paper are based on comparative analysis of the sliding wedge parameters for benches, dumps and roads at open pits using analytical and graphical software packages, and taking into account the static load produced by dump trucks. The study findings allow to establish that: determination of the bench slope stability and the sliding wedge width, performed by the analytical method, gives higher accuracy results than those obtained by the graphical method; the bench slope stability and the sliding wedge width depend not only on the rock physical and mechanical condition, but also on the bench height, the dump truck (plus its freight load) weight per 1 linear meter of the placement area, the distance from the slope edge and other factors; the rock mass is stable and not subject to landslide phenomena for as long as the sum of the holding forces is greater than or equal to the sum of the shearing forces; when using large-sized transport equipment of nonstandard weight in open-pit mining, it is necessary to calculate the safe width of the sliding wedges, taking into account the loads on them (per 1 linear meter), the values of which can be 1.5–2.0 times higher than those calculated for the circular-cylindrical sliding surface.


2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Rongxing He ◽  
Jing Zhang ◽  
Yang Liu ◽  
Delin Song ◽  
Fengyu Ren

Continuous mining of metal deposits leads the overlying strata to move, deform, and collapse, which is particularly obvious when open-pit mining and underground mining are adjacent. Once the mining depth of the adjacent open-pit lags severely behind the underground, the ultimate underground mining depth needs to be studied before the surface deformation extends to the open-pit mining area. The numerical simulation and the mechanical model are applied to research the ultimate underground mining depth of the southeast mining area in the Gongchangling Iron mine. In the numerical simulation, the effect of granular rock is considered and the granular rock in the collapse pit is simplified as the degraded rock mass. The ultimate underground mining depth can be obtained by the values of the indicators of surface movement and deformation. In the mechanical model, the modified mechanical model for the progressive hanging wall caving is established based on Hoke’s conclusion, which considers the lateral pressure of the granular rock. Using the limiting equilibrium analysis, the relationship of the ultimate underground mining depth and the range of surface caving can be derived. The results show that the ultimate underground mining depth obtained by the numerical simulation is greater than the theoretical calculation of the modified mechanical model. The reason for this difference may be related to the assumption of the granular rock in the numerical simulation, which increases the resistance of granular rock to the deformation of rock mass. Therefore, the ultimate underground mining depth obtained by the theoretical calculation is suggested. Meanwhile, the surface displacement monitoring is implemented to verify the reasonability of the ultimate underground mining depth. Monitoring results show that the indicators of surface deformation are below the critical value of dangerous movement when the underground is mined to the ultimate mining depth. The practice proves that the determination of the ultimate underground mining depth in this work can ensure the safety of the open-pit and underground synergetic mining.


2021 ◽  
pp. 102-106
Author(s):  
O. A. Isyanov ◽  
◽  
D. I. Ilderov ◽  
V. I. Suprun ◽  
S. A. Radchenko ◽  
...  

Instability of pit wall slopes is the most critical accident in open pit mining. The risk of damages to pit walls is proportional to the height of exposed surfaces and to the time of exposure. Among many factors governing pit wall stability, the major factor is geological structure and weakening zones in rock mass. Deformation processes are initiated in host rock mass of coal seams mostly because of undercutting of weak interlayers. Alongside with local undercutting, another cause of landslides is transition of coal mining from down-dip extraction to up-dip extraction. The sequence of mining and morphology of weak interlayers also have influence on initiation and evolution of deformations. The basic component of engineering solutions on pit wall stability control is optimization of mining sequence and methods of accessing working horizons in open pit mines. Large-scale deformation of Western and Southeastern pit walls in Urtui mine could be avoided using the optimized sequence of mining operations. For example, mining advance mostly along the curve of the Urtui centroclinal fold, with early access and destress of the eastern and, first of all, western wings of the fold could make it possible to evade from up-dip mining of coal seams and, as a consequence, to solve the major geomechanical problems in the open pit mine.


Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1913
Author(s):  
Marek Cała ◽  
Katarzyna Cyran ◽  
Joanna Jakóbczyk ◽  
Michał Kowalski

The extraction of the Bełchatów lignite deposit located in the vicinity of the Dębina salt dome requires careful planning that considers the influence of mining projects on the slope and salt dome stability conditions. The instability problem is directly related to horizontal and vertical displacement, as well as the complex geological and mining conditions. These conditions are very unique with regard to the co-occurrence of the salt dome and lignite deposits in the same area, as well as the large scale of the pit wall slope. Thus, predicting rock mass behavior and ensuring the safety of mining operations are important issues. The presented analysis focused on the influence of long-term lignite extraction on the western pit wall slope of the Bełchatów field and the salt dome’s stability conditions. This study offers a comprehensive approach to a complex geotechnical problem defined by large-scale, complex geometry, and geological conditions. The rock mass behavior and stress conditions are simulated in numerical modelling. The results of the presented analysis will be useful not only for present mining activities but also for future developments related to post-mining and recultivation plans.


2021 ◽  
Vol 303 ◽  
pp. 01059
Author(s):  
Vladimir Makarov ◽  
Valery Kolesnikov ◽  
Dawid Szurgacz

At the present time on the fields of operating and closed-down mines there are sections of open-pit operations. However, the adopted technology does not meet environmental requirements, there are no scientific recommendations on the technology of open-pit mining in hazardous areas of mine fields, there is no substantiation of the boundary contours of open-pit mining. A characteristic feature of depleted mine fields is the disturbed rock mass and the lack of concentrated coal reserves within their boundaries. In fact, coal reserves are represented in the form of fragmentary volumes of safety pillars and substandard reserves in places of geological disturbances. Limitation of mine fields in terms of various infrastructure objects imposes special requirements for mining operations. In these conditions it is not possible to apply the classic mining systems and technologies. This predetermines the necessity to develop new technological solutions. Therefore, scientific research on justification of technology for extraction of remaining reserves of coal after underground development of inclined and steep-sloping coal deposits with simultaneous reclamation of disturbed lands is actual.


2021 ◽  
Vol 304 ◽  
pp. 02002
Author(s):  
Vokhid Kadirov ◽  
Sherzod Karimov ◽  
Uchqun Qushshayev ◽  
Durdona Sharapova

The article presents a study and analysis of the causes of deformation of the slopes and sides of the quarry indicates that the magnitude and nature of the deformation processes depend on the height of the ledge, the angle of slope of the slopes, the physical and mechanical properties, the lithological and structural features of the instrument array and the geodynamic activity of the fault zones. The influence of the deformation zones of the sides of the quarry on the transport of rock masses is justified. The zone of deformed masses of the ore deposit, which affect the movement of the rock mass, is studied. Each process performed in open pit mining is linked to another workflow. Without ensuring the safety of mining operations and performing the tasks set is impossible. Transportation of rock masses in the lower horizons of a deep quarry is one of the main tasks of the industry. At the same time, the removal of deformation and landslides in the area where the transport berm is being constructed for draining and continuous transportation is the main goal of the quarry. The stability of the transport berm depends directly on the stability of the side of the quarry. It is determined that the choice of a single-lane or twolane transport berm constructed for heavy-duty quarry dump trucks depends on the condition of the side of the quarry.


2020 ◽  
Vol 177 ◽  
pp. 03016
Author(s):  
Nikolay Suslov ◽  
Stanislav Chernukhin

The article discusses the mechanisms of walking used on dragline excavators. The disadvantages of each mechanism are identified and based on this, the most promising movement mechanism is selected – a three-legged walking mechanism with a hydraulic drive. For this mechanism, the main disadvantages are also identified. The following is a technical solution that allows you to save this mechanism from the main drawback – the need to raise the center of mass of the excavator to a significant height to ensure the maximum step value. The technical solution includes the presence of a flat hydrostatic support that allows to increase the efficiency of the mechanism in open-pit mining operations. The calculation of oil consumption through a flat hydrostatic support in the conditions of its use on quarry soils with different bearing capacity is made.


2022 ◽  
Vol 354 ◽  
pp. 00035
Author(s):  
Edward Gheorghiosu ◽  
Daniela Rus ◽  
Ștefan Ilici ◽  
Sorin Mihai

In addition to the technical and economic advantages of blasting rocks from open-pit mining, this method of extraction can produce effects with a direct impact in the area near the open pit. Blasting works generates effects such as seismic waves that cause vibrations, rock throws, noise and toxic gases. When their intensity and scope are not systematically evaluated and analysed, blasting works can cause serious consequences for people, civil / industrial buildings, the environment, thus affecting the health of the population and the stability / integrity of the buildings / slopes in the vicinity of the mining operations. The paper presents design / determination methods of areas where explosives may / may not be used in conditions of maximum safety in terms of seismic intensity, thus protecting the population and the civil / industrial objectives in the area of the mining work. The obtained results are extracted from a research study carried out for the opening in operation of a new mining deposit, having as reference calculations and theoretical interpretations related to the conditions established for the development of the blasting works.


2021 ◽  
Vol 11 (22) ◽  
pp. 10848
Author(s):  
Natalia Koteleva ◽  
Sergei Khokhlov ◽  
Ilia Frenkel

Mining enterprises are widely introducing digital technologies and automation is one of such tools. Granularity monitoring, namely, the size determination of rock mass pieces is a common operational component of the processes that extract minerals by open-pit mining. The article proposes an approach that, in addition to the lump size distribution, makes it possible to estimate the lump form distribution as well. To investigate the effectiveness of monitoring the form of blasted rock mass lumps, the authors conducted experiments in four stages related to the rock condition. They include geological occurrence, explosive crushing, trommelling, and mill crushing. The relationship between these stages is presented and the change in the lumps fragment form is traced. The present article proposes an informational and analytical model of the processes at mining enterprises, extracting minerals by open-pit mining, as well as an algorithm for determining the lumps form and obtaining their distribution in the rock mass.


Author(s):  
Diakov A. Iu ◽  

Introduction. Development of deep open pits requires reliable knowledge on conditions of rocks at the hard rock mass to locate potentially hazardous sectors which have considerable impact on efficiency and rationality of a deposit’s development. Definition of disturbed zones at the open pit benches is an actual scientific and practical task in terms of supporting stability and functionality of such facilities. Research aim is to study geophysical signs of disturbance of hard rocks by data of nondestructive ground-penetrating radar (GPR) observation of the surrounding rock mass at the working open pit benches in order to estimate their geological structure and differentiate by disturbance degree. Methodology. Nowadays, GPR data is overwhelmingly interpreted based on comprehensive analysis of amplitude, frequency and phase characteristics of an electromagnetic signal and without an attribute analysis of the wave field. When using the structural approach, based on the analysis of the dynamic and kinematic characteristics of the wave field, to identify hard rock disturbance areas, it becomes possible to significantly increase the accuracy of their determination and localization according to the nondestructive subsurface GPR research. Results. Based on GPR measurements, the author has studied geophysical signs of disturbed rock zones identification at the open pit benches which consist in a quantitative estimation of change in reflection response amplitude characteristic, permittivity of a section and Q factor attribute. Conclusion. Using the established relationships with the proposed analysis of geophysical signs, the GPR study data can contribute to the adoption of differentiated and providing greater stability parameters of benches and mining operations.


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