-
Date submitted2023-03-14
-
Date accepted2023-10-25
-
Date published2024-04-25
Predictive assessment of ore dilution in mining thin steeply dipping deposits by a system of sublevel drifts
The purpose of research is the study of stress-strain state of marginal rock mass around the stope and predictive assessment of ore dilution with regard for changes in ore body thickness in mining thin ore deposits on the example of the Zholymbet mine. Study of the specific features of the stress-strain state development was accomplished applying the methodology based on numerical research methods taking into account the geological strength index (GSI) which allows considering the structural features of rocks, fracturing, lithology, water content and other strength indicators, due to which there is a correct transition from the rock sample strength to the rock mass strength. The results of numerical analysis of the stress-strain state of the marginal part of the rock mass using the finite element method after the Hoek – Brown strength criterion made it possible to assess the geomechanical state in the marginal mass provided there are changes in ore body thickness and to predict the volume of ore dilution. It was ascertained that when mining thin ore deposits, the predicted value of ore dilution is influenced by the ore body thickness and the GSI. The dependence of changes in ore dilution values on the GSI was recorded taking into account changes in ore body thickness from 1 to 3 m. Analysis of the research results showed that the predicted dimensions of rock failure zone around the stopes are quite large, due to which the indicators of the estimated ore dilution are not attained. There is a need to reduce the seismic impact of the blasting force on the marginal rock mass and update the blasting chart.
-
Date submitted2021-12-16
-
Date accepted2022-04-07
-
Date published2022-07-13
The Upper Kotlin clays of the Saint Petersburg region as a foundation and medium for unique facilities: an engineering-geological and geotechnical analysis
- Authors:
- Regina E. Dashko
- Georgiy A. Lokhmatikov
The article reviews the issues concerned with correctness of the engineering-geological and hydrogeological assessment of the Upper Kotlin clays, which serve as the foundation or host medium for facilities of various applications. It is claimed that the Upper Kotlin clays should be regarded as a fissured-block medium and, consequently, their assessment as an absolutely impermeablestratum should be totally excluded. Presence of a high-pressure Vendian aquifer in the lower part of the geological profile of the Vendian sediments causes inflow of these saline waters through the fissured clay strata, which promotes upheaval of tunnels as well as corrosion of their lining. The nature of the corrosion processes is defined not only by the chemical composition and physical and chemical features of these waters, but also by the biochemical factor, i.e. the availability of a rich microbial community. For the first time ever, the effect of saline water inflow into the Vendian complex on negative transformation of the clay blocks was studied. Experimental results revealed a decrease in the clay shear resistance caused by transformation of the structural bonds and microbial activity with the clay’s physical state being unchanged. Typification of the Upper Kotlin clay section has been performed for the region of Saint Petersburg in terms of the complexity of surface and underground building conditions. Fissuring of the bedclays, the possibility of confined groundwater inflow through the fissured strata and the consequent reduction of the block strength as well as the active corrosion of underground load-bearing structures must be taken into account in designing unique and typical surface and underground facilities and have to be incorporated into the normative documents.
-
Date submitted2018-11-20
-
Date accepted2018-12-28
-
Date published2019-04-23
Refined assessment of seismic microzonation with a priori data optimisation
- Authors:
- I. B. Movchan
- A. A. Yakovleva
The work is devoted to the issues of seismic microzonation representativeness, which is amongst the mandatory assessments that precedes civil and industrial construction. In addition to the practical approach and in accordance with the normative documentation, the authors propose parametric interpretation of the remote basis by means of tracing geodynamic zones and elements of the geoblock structure, where the leading marker of seismogenic risk zones is the anomaly of spatial variability of the geofield, coinciding with the discordant intersection of localised land structures. Verification of this marker is achieved by displaying a cartographic distribution image within the range of the seismic point increment, detailed on the basis of approximation dependencies.
-
Date submitted2016-11-21
-
Date accepted2017-01-23
-
Date published2017-04-14
Prospects of obtaining samples of bottom sediments from subglacial lake Vostok
- Authors:
- N. I. Vasilev
- G. L. Leichenkov
- E. A. Zagrivnyi
The paper proves the timeliness of obtaining and examining bottom sediments from subglacial Lake Vostok. Predictive geological section of Lake Vostok and information value of bottom sediments have been examined. Severe requirements towards environmental security of lake examinations and sampling of bottom sediments rule out the use of conventional drilling technologies, as they would pollute the lake with injection liquid from the borehole. In order to carry out sampling of bottom sediments from the subglacial lake, it is proposed to use a dynamically balanced tool string, which enables rotary drilling without any external support on borehole walls to transmit counter torque. A theoretical analysis has been carried out to assess the operation of the tool string, which is a two-mass oscillatory electromechanical system of reciprocating and rotating motion (RRM) with two degrees of freedom.
-
Date submitted2013-07-09
-
Date accepted2013-09-01
-
Date published2014-03-17
Certain periodicity organizational and technical preventive measures, aimed at improving the effective management of safety on coal open pit mining
- Authors:
- E. B. Gridina
- A. V. Pasynkov
Developing preventative preventive measures is one of the key ways to increase the effectiveness of occupational health and safety of miners. Integrated use of probabilistic and expert - analytical methods for analysis of injury, in particular it allows to develop a plan and to deter-mine the frequency of short-term preventive measures.
-
Date submitted2013-07-06
-
Date accepted2013-09-09
-
Date published2014-03-17
Primary forecast of density-related nonstationarity of cross-section upper part
- Authors:
- I. B. Movchan
- V. Yu. Asyanina
The state of profile higher part state and the directly depended housing stock are determined by geological factors and human influence. It both define time variation of the density of surface states structural and material systems. Gravimetric survey for the gravitational field temporal dynamics is the cheap method for its rapid assessment. Its description can be done at two levels: the structural one (qualitative) and the depth (quantitative).
-
Date submitted2009-08-17
-
Date accepted2009-10-12
-
Date published2010-02-01
Complex geological engineering and geoenvironmental monitoring as a basis for creation of strategy of Saint Petersburg architectural and historical monuments conservation
- Authors:
- A. V. Shidlovskaya
In the paper concept and structural of complex engineering geological and geoenvironmental monitoring of architectural and historical monuments are considered. The specificity of engineering geological and hydrogeological conditions by the example of the Isaac Cathedral, the Kazan Cathedral and the Peter and Paul Cathedral is analyzed. The geoenvironmental condition of architectural and historical monuments underground space is estimated. The factors which influence on monuments deformation due to the high degree of underground space transformation and activity of negative natural and technogenic processes are shown. The system of impact monitoring of the Isaac Cathedral, the Kazan Cathedral and the Peter and Paul Cathedral is proposed.
-
Date submitted2008-10-08
-
Date accepted2008-12-08
-
Date published2009-12-11
Georadar investigations of shallow depth оf geological section and engineering constructions
- Authors:
- V. V. Glazunov
- N. N. Efimova
The GPR-method showing high resolution, great performance and sensitivity to minor variations in the composition and conditions of soils and material has assumed a role of the leading geophysical method for looking at the upper part of the geological section. This paper presents the advanced directions of GPR application for engineering problems solution.
-
Date submitted1958-03-07
-
Date accepted1958-05-17
-
Date published1958-05-09
К СТРАТИГРАФИИ ВЕРХНЕПРОТЕРОЗОЙСКОЙ ТОЛЩИ МЕТАМОРФИЧЕСКИХ ПОРОД ЮГО-ВОСТОЧНОЙ ЧАСТИ ТУВЫ
- Authors:
- Unknown
Верхнепротерозойская толща метаморфических пород на правобережье р. Эрзин, к западу от ее правого притока (р. Улар), А. В. Ильиным и В.М. Моралевым подразделяется на две серии: нижнюю — терригенную и верхнюю — карбонатную. В каждой из них выделяются по две свиты: тесхемская и мугурская, балактыкхемская и чартисская. Краткое описание разреза (снизу вверх) следующее…
-
Date submitted1958-03-10
-
Date accepted1958-05-23
-
Date published1958-05-09
НЕКОТОРЫЕ ОСОБЕННОСТИ ГЕОЛОГИЧЕСКОГО СТРОЕНИЯ ОДНОГО ИЗ УЧАСТКОВ ЦЕНТРАЛЬНОГО РАЙОНА ДОНБАССА
- Authors:
- Unknown
В геологическом строении исследованной территории принимают участие породы свит.С 2 и С 3 угленосной толщи среднего карбона, которые выходят на поверхность в виде узкой (0,5—2,5 км) полосы вдоль оси Главной Донецкой антиклинали, именуемой в этой части Горловской. Севернее и южнее этой полосы на поверхность выходят породы вышележащих угленосных свит, образующих крылья складки. Породы здесь имеют крутое (50—65°) падение, а выходы их почти прямолинейно простираются в западно-северо-западном и восточно-юго-восточном направлениях. Осевая часть антиклинали усложнена мелкими складчатыми формами и большим количеством разрывных нарушений, различных по возрасту и характеру.