ESTIMATED ANALYSIS OF THE NATURAL STRESS FIELDS COMPLEXITY IN EASTERN SAYAN GOLD-ORE VEIN DEPOSITS

2021 ◽  
Vol 4 (1) ◽  
pp. 464-474
Author(s):  
E.L. Sosnovskaya ◽  
◽  
A.N. Avdeev
Keyword(s):  
Rock Pressure ◽  
Initial Stresses ◽  
Stress Fields ◽  
Depth Range ◽  
Statistical Parameters ◽  
Gold Ore ◽  
Natural Stress ◽  
Vein Deposits ◽  
Eastern Sayan

The article presents the main results of studies of initial stresses of three gold vein de-posits located in the Eastern Sayan Mountains: Zun-Kholbinsky, Barun-Kholbinsky, Konevin-sky, in the depth range of 120…940 m. Insitu measurements by the slot unloading method and reverse calculation of primary stresses on the basis of 49 rock pressure cases were made. Key geomechanical factors were determined, and average statistical parameters of natural stresses depending on the combination of these factors were estimated.

scholarly journals Mineralogical and geochemical characteristics of the Nadezhda gold ore prospect, Eastern Sayan

2019 ◽  
Vol 42 (4) ◽  
pp. 413-424
Author(s):  
Alexandra Izvekova ◽  
◽  
Bulat Damdinov ◽  
Lyudmila Damdinova ◽  
Maria Moskvitina ◽  
...  
Keyword(s):  
Geochemical Characteristics ◽  
Gold Ore ◽  
Eastern Sayan

scholarly journals Geomechanical conditions of vein gold deposits in permafrost zone

2020 ◽  
Vol 192 ◽  
pp. 01026
Author(s):  
Arkady Avdeev ◽  
Elena Sosnovskaya
Keyword(s):  
Field Measurements ◽  
Gold Deposits ◽  
Permafrost Zone ◽  
Initial Stresses ◽  
Qualitative Assessment ◽  
Electric Transport ◽  
Mining Operations ◽  
Initial Development ◽  
Temperature Conditions ◽  
Vein Deposits

Developing the vein deposits in the permafrost zone results in specific geomechanical conditions. The paper describes the main results of studies of the geomechanical conditions of 8 vein deposits located in the permafrost zone for 2000-2020. In the process of research, zoning of the temperature conditions in mines has been carried out. The research has established the position of the permafrost zones, the natural transition zones of frozen rocks to thawed rocks, the zones of seasonal ventilation thawing and technogenic thawing. The authors have made the qualitative assessment of the degree of stability of the mine workings and pillars, taking into account the temperature conditions. It is proposed, when evaluating the stability of structural elements of geotechnologies, to adjust the strength properties of rocks using a differentiated coefficient of structural weakening. The paper has presented the results of field measurements of the initial stress-deformed state at various temperature conditions. The general regularities of the distribution of initial stresses are established: hydrostatic stresses act in frozen rocks, and increased gravitational-tectonic stresses act in natural and technogenic thawed rocks. The authors have proposed to use the obtained results as boundary conditions for the calculation of geotechnological parameters in the design and initial development of vein gold deposits of the permafrost zone. The authors have proposed the measures to improve the safety of mining operations in permafrost: thermal insulation of mine walls, use of electric transport, regulation of ventilation.

scholarly journals Evaluation of geomechanical conditions at Magnezitovaya mine when undermining natural and anthropogenic objects

2018 ◽  
Vol 56 ◽  
pp. 02017 ◽  
Author(s):  
Roman Krinitsyn ◽  
Arkady Avdeev ◽  
Sergei Khudyakov
Keyword(s):  
Rock Pressure ◽  
Physical And Mechanical Properties ◽  
Industrial Safety ◽  
Initial Stresses ◽  
Mining Operations ◽  
Research Guidelines ◽  
Magnesite Deposit ◽  
River Bed ◽  
The Stability ◽  
Long Term Observation

Development of Satka magnesite deposit is carried out in complicated geomechanical conditions, in particular, mining works are conducted under the Bolshaya Satka river, in the zone of influence of the existing and developed quarries. Underground workings undermine a number of surface objects of industrial and civil purpose: railways, bridges, buildings and structures. There was an urgent need to conduct special studies of geomechanical conditions at the mine in order to assess the feasibility of working off part of the safety pillars located under the railway tracks of "Russian Railways", PJSC and the river bed. In the process of research, the main physical and mechanical properties of rocks have been identified, and the initial natural stresses of the rock mass have been measured. An increased level of horizontal initial stresses in the zone of safety pillars at the horizons + 180. + 260 m was detected. Based on the results of the research, a conclusion was made on the need to develop some engineering measures to ensure the safety of underground works. It was recommended, to ensure the stability of the rocks massif, to apply the option of extracting the treatment chambers with the formation of the ceiling of the vaulted form. It is proposed to monitor deformation processes in mine workings and on the daylight surface. To this end, the installation of an automated control system for rock pressure is recommended. It is necessary to provide for the establishment of long-term observation stations for controlling rock pressure and displacement. According to the results of the research, "Guidelines for the safe control of mining operations at bump-hazardous Satka magnesite deposit" have been developed in accordance with the requirements of the Federal norms and regulations in industrial safety.

Numerical Simulation on Stress Fields of Lasers Braze Fusion Welding

2007 ◽  
Vol 26-28 ◽  
pp. 963-968
Author(s):  
Ping Dong ◽  
Rui Wen Li
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Diffraction Method ◽  
Fusion Welding ◽  
Welding Residual Stress ◽  
Initial Stresses ◽  
Stress Fields ◽  
X Ray Diffraction ◽  
Fem Model ◽  
Change Trend

The assembled tube was made of beryllium tube and tungsten tube, and was produced by over fitting. The residual stresses in the assembled tube were very comprehensive after lasers braze fusion welding, not only including the welding residual stresses, but also the initial stresses from over fitting. Both of the dimension and strength were affected by the complex residual stress distribution in the assembled tube. MSC.MARC software was used to simulate the stress fields during lasers braze fusion welding of the assembled tube. The stress fields during lasers braze fusion welding and the residual stresses after welding have been obtained, and the effect of over fitting on welding residual stress of the assembled tube have also been studied. The residual stresses at outer surface of the assembled tube have been measured by the X-ray diffraction method. A comparison of the residual stresses by finite element method (FEM) to that by experiment indicates an identical stress change trend and thus validates the FEM model.

scholarly journals Mineralogy and Geochemistry of Gold Ore Low Sulfidation -Epithermal at Lamuntet, Brang Rea, West Sumbawa District, West Nusa Tenggara Province

2019 ◽  
Vol 4 (3) ◽  
pp. 198
Author(s):  
Rika Ernawati ◽  
Arifudin Idrus ◽  
Himawan Tri Bayu Murti Petrus
Keyword(s):  
Xrd Analysis ◽  
Atomic Absorption Spectrophotometry ◽  
Small Scale ◽  
X Ray ◽  
Gold Ore ◽  
Gold Silver ◽  
Chemical Content ◽  
Vein Deposits ◽  
Gold Mineral ◽  
Low Sulfidation

There are two Artisanal Small scale Gold Mining (ASGM) location in Lamuntet, Brang Rea Subdistrict, West Nusa Tenggara Regency, namely Nglampar and Song location. Nglampar and Song location are included in the low sulfidation epithermal gold deposit system. The research purposes to analyze mineralogy and geochemistry of gold vein deposits and determine system of low sulfidation gold ore in Nglampar, Lamuntet Village. The methods used to determine the mineralogy of gold vein deposits are petrography, mineragraphy and X-ray diffractometer (XRD) analysis, while geochemical analysis using Scanning Electron Microscope (SEM) with Energy Dispersive X-Ray Spectroscopy (EDS), Fire Assay (FA) and Atomic Absorption Spectrophotometry (AAS). The results showed that the minerals contained were quartz (Qz), sericite (Ser), Chalcedon (Chc), chlorite (Chl), pyrite (Py), sphalerite (Sph), galena (Gn) , gold (Au), chalcopyrite (Cp), argentite (Ag), arsenopyrite (Apy), Azurit (Az), Malakit (Mal) and bornite (Bn). Abundant mineral availability such as sphalerite, galena, chalcopyrite and arsenopyrite are characterized by high levels of Zn, Pb, Cu and As the metal in vein deposits. This can be seen on the chemical content of ore in gold vein deposits ie Au 0.1 ppm -27.8 ppm, Ag 3 ppm-185 ppm, Pb 101 ppm - 35,800 ppm, Zn 73 ppm-60,200 ppm, Cu 26 ppm - 1,740 ppm, and As 150 ppm - 6,530 ppm. Based on the results of SEM-EDS analysis shows that the type of gold mineral is the electrum because of the content of Ag> 20%.  Based on those characteristics of the mineralogy and geochemistry in this study showed that low sulfidation gold ore in this area is categorized as polymetallic gold-silver system. 

ON «STEP OF ALLOCATION» AND FORECASTING OF THE VEIN GOLD ORE BODIES

2018 ◽  
pp. 32-44
Author(s):  
E. M. Nekrasov
Keyword(s):  
Deep Level ◽  
Low Grade ◽  
High Grade ◽  
Near Surface ◽  
Gold Ore ◽  
Vertical Range ◽  
Ore Bodies ◽  
Vein Deposits ◽  
Upper Level ◽  
Step Distance

On the example of a number of domestic and foreign gold vein deposits it has been shown that the system of gold-ore bodies is located along some narrow local ore controlling displacements in a shape of veins. These veins are located at approximately equal distances from each other - at allocation step. This step varies from 30—70 m to 100— 250 m for different deposits. It allows forecasting of ore bodies at the flanks of the displacements and exploration by drilling. On the example of near-surface deposits it has been confirmed that such ore bodies can be formed at two vertical ore-bearing levels — upper and lower (deep). The upper level appears at very narrow vertical range of depths (100-300 m) near the paleosurface, presumably in the alumstone-adular-kaolinic metasomatites. Here the rhythmically-banded ores with low-grade gold are formed. At the lower (deep) level, the ore bodies can be formed in the interval of 600-1000 m and deeper from the paleosurface in the zones of tectonic breccia, crossing the metasomatites of the secondary quartzites type. They are more often to be the place of the localization of breccia structure ores with comparatively high-grade gold. So, at the near-surface deposits it is possible to explore the new (in particular, blind) ore bodies in allocation step distance from each other at two levels of mineralization, and, moreover, at the significant depth.

Bivariate Fourier-series-based prediction of surface residual stress fields using stresses of partial points

2018 ◽  
Vol 24 (4) ◽  
pp. 979-995 ◽  
Author(s):  
Fengyun Wang ◽  
Kuanmin Mao ◽  
Shanguo Wu ◽  
Bin Li ◽  
Gang Xiao
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Fourier Series ◽  
Stress Field ◽  
Residual Stresses ◽  
Initial Stresses ◽  
Stress Fields ◽  
Critical Parameters ◽  
Generation Process ◽  
Surface Residual Stress

Surface residual stresses are critical parameters for evaluating the surface quality and can have an influence on many mechanical properties of solids. These stresses inevitably arise in almost all engineering components during manufacturing. However, most experimental and finite element approaches cannot obtain a complete surface residual stress field in a mechanical part. In this study, we propose a predictive method to determine surface stress fields, depending on residual stresses being self-equilibrating. The effectiveness of the approach is verified using a numerical surface of a beam example with ideal measurements and a casting–milling surface with experimental data. Using the proposed method, surface residual stress fields can be obtained from the stresses of a limited number of points including boundary points to solve the governing equations via a Fourier series bivariate polynomial as an Airy stress function with the Tikhonov regularization method. Our method does not require simulations of the residual stress generation process. This method is suitable for complex engineering parts where the manufacturing process is difficult to recreate in detail. The predicted stress field can be imported into a finite element solver as initial stresses to promote the design, manufacturing, and assessment of mechanical components.

Statistical parameters of the indicating surface of natural reflectance for biaxial transparent media

1997 ◽  
Vol 44 (9) ◽  
pp. 1661-1670
Author(s):  
José Manuel Din Eiro ◽  
Santiago Alfonso ◽  
Coro Alberdi ◽  
Miguel Berrogui
Keyword(s):  
Statistical Parameters ◽  
Transparent Media
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