Use of geophysical methods for investigating the saturation of rock-mass

1999 ◽  
Author(s):  
M. Henryk ◽  
T. S. Sylwia
Keyword(s):  
Rock Mass ◽  
Geophysical Methods

Application of geophysical methods for the investigation of the large gravitational mass movement of Séchilienne, France

2005 ◽  
Vol 42 (4) ◽  
pp. 1105-1115 ◽  
Author(s):  
O Meric ◽  
S Garambois ◽  
D Jongmans ◽  
M Wathelet ◽  
J L Chatelain ◽  
...  
Keyword(s):  
Rock Mass ◽  
Mass Movement ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Time Lapse ◽  
Gravitational Mass ◽  
Electrical Tomography ◽  
Refraction Tomography ◽  
Geophysical Surveys ◽  
Geophysical Techniques

Several geophysical techniques (electromagnetic profiling, electrical tomography, seismic refraction tomography, and spontaneous potential and seismic noise measurement) were applied in the investigation of the large gravitational mass movement of Séchilienne. France. The aim of this study was to test the ability of these methods to characterize and delineate the rock mass affected by this complex movement in mica schists, whose lateral and vertical limits are still uncertain. A major observation of this study is that all the zones strongly deformed (previously and at present) by the movement are characterized by high electrical resistivity values (>3 kΩ·m), in contrast to the undisturbed mass, which exhibits resistivity values between a few hundred and 1 kΩ·m. As shown by the surface observations and the seismic results, this resistivity increase is due to a high degree of fracturing associated with the creation of air-filled voids inside the mass. Other geophysical techniques were tested along a horizontal transect through the movement, and an outstanding coherency appeared between the geophysical anomalies and the displacement rate curve. These preliminary results illustrate the benefits of combined geophysical techniques for characterizing the rock mass involved in the movement. Results also suggest that monitoring the evolution of the rock mass movement with time-lapse geophysical surveys could be beneficial.Key words: gravitational movement, geophysical methods, Séchilienne.

scholarly journals Geophysical identification of voids and loosened zones in the shallow subsurface of post-mining areas

2018 ◽  
Vol 66 ◽  
pp. 01001 ◽  
Author(s):  
Zenon Pilecki
Keyword(s):  
Rock Mass ◽  
Geophysical Methods ◽  
Ore Deposits ◽  
Hard Coal ◽  
Shallow Subsurface ◽  
Mining Areas ◽  
Upper Silesian Coal Basin ◽  
Discontinuous Deformation ◽  
Ground Penetrating ◽  
Terrain Surface

The shallow historic exploitation of Zn-Pb/Fe ore deposits as well as hard coal has generated many discontinuous deformations on the terrain surface in the Upper Silesian Coal Basin/Poland. Discontinuous deformations occur in different forms as sinkholes, synclines, cracks, faults or ditches. The basic cause of their occurrence is the presence of void and loosened zones in the shallow subsurface. If the appropriate conditions arise, the sinkhole process begins to move upwards and may cause a discontinuous deformation on the terrain surface. Typically, geophysical methods are used for void and loosened zone identification. The most effective methods are gravimetric, seismic, electric resistivity and ground penetrating radar (GPR). Geophysical testing, requires distinct changes in the physical properties in the rock mass. The identified geophysical anomalies should be verified by control borehole and borehole tests to confirm the presence of the void and loosened zones in the rock mass. The results of control drilling and borehole tests determine the need to apply treatment works. In order to assess the threat of the occurrence of discontinuous deformations in the areas of historical shallow mining in Upper Silesia, a classification system based on geophysical tests has also been developed.

Estimation of rock mass strength and water content by geophysical methods

2018 ◽  
pp. 61-64
Author(s):  
V. V. Romanov ◽  
◽  
K. S. Malsky ◽  
A. I. Poserenin ◽  
A. D. Karinsky ◽  
...  
Keyword(s):  
Rock Mass ◽  
Water Content ◽  
Geophysical Methods ◽  
Rock Mass Strength

scholarly journals Study of Rock Mass Stability Decrease due to Underground Mining

2020 ◽  
Vol 4 (4) ◽  
pp. 251-261
Author(s):  
V. I. Golik ◽  
S. A. Maslennikov ◽  
Alberto Martin Nunez Rodriguez ◽  
V. I. Anischenko
Keyword(s):  
Rock Mass ◽  
Energy Management ◽  
Underground Mining ◽  
Geophysical Methods ◽  
Electrode System ◽  
Stability Study ◽  
Rock Masses ◽  
Rock Mass Structure ◽  
Rock Mass Stability ◽  
Specific Metal

The optimization of underground mining processes is carried out based on rational use of energy for obtaining preset broken ore size. The effective optimization requires correct assessment of the properties of the rock mass to be broken. Energy management requires assessment of rock mass stability decrease due to impact of natural and technogenic stresses. To make adjustments to the general energy management model, information on the rock mass structure is required to be obtained by geophysical methods. To optimize broken rock/ore size (to minimize oversized or excessively crushed mineral fraction yield during breaking), blasting energy application should be regulated and smart. The study is aimed at assessing the effectiveness of using geophysical methods for the prompt and correct assessment of rock and backfill mass condition during underground mining of mineral deposits. Decreasing stability of rock masses is assessed using the method of electrometric surveys in noncore exploratory boreholes. Rock mass stability study allowed revealing correlation and dependencies between the studied parameters. Effectiveness of using geophysical methods for differentiating natural and technogenic masses by degree of decreasing their stability due to geological and technogenic stresses. To determine the coefficient of decreasing rock mass stability based on rock apparent resistivity data, electrometric logging was used. This allowed to differentiate rock mass by the degree of decreasing rock mass stability based on the revealed dependency. The features of the geophysical survey components are described in details. The methodology and findings of the underground electric sounding using a sequential gradient electrode system at specific metal deposit are presented, including using theoretical curves and determining rock conductivity and the distance to workings. Besides, correctness of the geophysical method findings was assessed differentially. The assessment was prepared for decreasing rock mass stability based on electrometric logging data, and for advance outlining heterogeneity zones in rock masses by electric sounding along working walls. Based on findings of the conducted experimental work on revealing structural boundaries within rock mass, the method of electric sounding along working walls was recommended for application in practice. As for the studied borehole electric sounding application, the convergence of the experimental and theoretical curves is insufficient to recommend the method for practical application.

scholarly journals Geophysical monitoring of the development of stress-deformed ore massives

2021 ◽  
Author(s):  
В.И. Голик ◽  
О.Г. Бурдзиева ◽  
Б.В. Дзеранов
Keyword(s):  
Rock Mass ◽  
Complex Structure ◽  
Geophysical Methods ◽  
Practical Experience ◽  
The State ◽  
Theory And Practice ◽  
Structure Theory ◽  
Nature Management ◽  
Reliability Factor ◽  
Communication Processes

Рассмотрены актуальные вопросы рационализации природопользования, включающие в себя установление величины и закономерностей экологического риска технологических процессов, оценку процессов коммуникации техногенных продуктов и прогнозирование экологической зависимости биоты от горного производства при подземной разработке месторождений Садонского рудного узла. Целью исследований является определение форм взаимодействия природных и технических систем, определяющих параметры геомеханики участка земной коры в районе освоения недр путем исследования напряженно-деформированного состояния массивов для разработки приемлемых вариантов добычи металлических руд. Методы исследования. Приведены результаты моделирования состояния рудовмещающих массивов на оптически активных материалах. Предложен коэффициент надежности для оценки безопасности горных технологий по развитию критических напряжений и деформаций. Результаты работы. Установлена адекватная зависимость между характером силового воздействия на природные и искусственные массивы и их устойчивостью с корреляцией между напряженностью массива и сохранностью земной поверхности, как гаранта безопасности экосистем биосферы. Даны результаты моделирования напряженности массива методом конечных элементов, распределения давления по контуру выработки на крепь и исследования фильтрационной неоднородности руд. Обобщены результаты анализа ретро-и перспектив развития способов управления состоянием массивов при разработке месторождений. Сделан вывод о возможности обеспечения оптимального соотношения напряжений в элементах геомеханической системы геофизическими методами в рамках мониторинга состояния горного массива и подземных выработок. В совокупности рекомендации представляют собой программу выхода горных предприятий региона из затяжного кризиса и восстановления былого потенциала одного из флагманов цветной металлургии, реализация которой формирует экономический, экологический и социальный эффект в условиях депрессивного промышленного региона. Topical issues of rationalization of nature management are considered, including the establishment of the magnitude and regularities of the ecological risk of technological processes, the assessment of the communication processes of technogenic products and the prediction of the ecological dependence of biota on mining during the underground development of the deposits of the Sadonsky ore cluster. The Aim of the research is to comprehensively study the interaction of natural and technical systems that ensure the geomechanical balance of massifs in the area of subsoil development by systematic monitoring of the stress-strain state of the massifs using the methods of complex generalization, analysis of practical experience and scientific achievements in the field of underground ore mining in the massifs. Complex structure, theory and practice of destruction of solid media by means of continuum mechanics and mathematical statistics with the development of economically and environmentally acceptable options for the extraction of metal ores. Methods. The results of modeling the state of ore-bearing massifs on optically active materials are presented. A reliability factor is proposed for assessing the safety of mining technologies for the development of critical stresses and deformations. Results. An adequate relationship has been established between the nature of the force impact on natural and artificial massifs and their stability with the correlation between the strength of the massif and the safety of the earth's surface, as a guarantor of the safety of biosphere ecosystems. The results of modeling the tension of the massif by the finite element method, the distribution of pressure along the contour of the excavation on the support and the study of the filtration heterogeneity of ores crushed for leaching purposes according to the propagation velocity of stress waves are given. The results of the analysis of retro- and prospects for the development of methods for managing the state of rock mass in the development of fields are generalized. A conclusion is made about the possibility of ensuring the optimal stress ratio in the elements of the geomechanical system by geophysical methods within the framework of monitoring the state of the rock mass and underground workings. Taken together, the recommendations represent a program for the recovery of the region's mining enterprises from a protracted crisis and the restoration of the former potential of one of the flagships of non-ferrous metallurgy, the implementation of which creates an economic, environmental and social effect in a depressed industrial region.

scholarly journals High-energy seismic events in Legnica–Głogów Copper District in light of ASG-EUPOS data

2019 ◽  
Vol 107 (1) ◽  
pp. 25-40 ◽  
Author(s):  
Zbigniew Szczerbowski
Keyword(s):  
Rock Mass ◽  
Regional Scale ◽  
Geophysical Methods ◽  
Geodetic Network ◽  
High Energy ◽  
Tectonic Activity ◽  
Baseline Length ◽  
Seismic Events ◽  
Gnss Data ◽  
Mining Tremors

AbstractSeismic events in the area of Poland are related mostly to copper and coal mining, and they are regarded as the most dangerous natural hazard. Although development of geomechanical modelling as the development of geophysical methods determining seismic hazard are evident, low predictability of the time-effect relationship still remains. Geomechanical models as geophysical data analysis highlight the interaction between parts of rock mass or allow to reconstruct the way of rock mass destruction and to understand the processes that take place in the high-energy tremors.However, the association of larger mining tremors with pre-existing geological features has been reported by many investigators; in geomechanical practice, investigations of rock mass condition concentrate on this problem in the local scale. Therefore, the problem of relations between high-energy seismic events in Legnica–Głogów Copper District (LGCD) and regional scale deformations of terrain surface resulting from possible tectonic activity is discussed in this paper. The GNSS data evaluated from the observations of ASG-EUPOS (Active Geodetic Network – EUPOS) stations in the area of LGCD and in the adjacent areas is analysed in this study. Temporal variation of distances between the stations and evaluated on that base so called apparent strain was combined with the occurrence of high-energy tremors. Consequently, after the examination and analysis of occurrences of mining tremors, it is found that high-energy seismic events and periods of strain accumulation evaluated from GPS/GNSS data have temporal relations. Although the seismic events were triggered by mining, nearly all the events with energy E > 108 J occurred in the periods when the analysed stations’ positions demonstrated a decrease in the baseline length.

Geophysical research of the rock massif in underground mine conditions

2020 ◽  
pp. 255-263
Author(s):  
T. F. Kharisov ◽  
V. V. Mel’nik ◽  
O. D. Kharisova ◽  
A. L. Zamjatin
Keyword(s):  
Rock Mass ◽  
Geophysical Methods ◽  
Oil Industry ◽  
High Accuracy ◽  
Underground Mine ◽  
Geophysical Research ◽  
Structural Inhomogeneities ◽  
Spectrum Density ◽  
Radar Sensing

Geophysical methods of research of rock mass are one of the most effective ways of solving various problems in mining and are widely used in mining, gas and oil industry, as well as in science. They allow remote search and assessment works, detection of structural inhomogeneities, voids, contact zones of various media in the rock mass with sufficient high accuracy. The article presents research and comparative analysis of geophysical methods of geophysical sensing and spectral seismo-profiling in underground mine conditions with determination of permissible tasks for which these methods are capable. In complex geophysical studies, methods of spectral seismo-profiling and geo-radar sensing in underground mine conditions have been applied. Measurements were made to search for different objects and at different angles to the object being searched. The use of geophysical methods made it possible to detect the metal shelf under the bulked rock mass with the separation of the boundaries of two tiers of the shelf during vertical measurements. In the process of searching for the underlying excavation in the mass during vertical geophysical measurements, which were carried out 20 meters from the shaft, a change in spectrum density at a depth of about 55 m was detected, which coincides with the actual location of the required mine working. The results of the search for caverns in the rock mass, when taking measurements at an angle to the object sought, showed the absence of sufficiently explicit boundaries of the caverns.

scholarly journals Investigation of Dimension Stone on the Island Brač—Geophysical Approach to Rock Mass Quality Assessment

Geosciences ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 112 ◽  
Author(s):  
Jasmin Jug ◽  
Kristijan Grabar ◽  
Stjepan Strelec ◽  
Filip Dodigović
Keyword(s):  
Electrical Resistivity ◽  
Rock Mass ◽  
Geophysical Methods ◽  
Dimension Stone ◽  
Seismic Velocities ◽  
Good Tool ◽  
Rock Mass Structure ◽  
Rock Mass Quality ◽  
Refraction Seismic ◽  
Geophysical Investigations

A site located on the island of Brač is known in history for world-famous architectural stone and stone mining, dating all the way back to ancient Greek and Roman times. The most famous building constructed from the stone from Brač is the Diocletian Cesar Palace in the town Split. Prospective new locations for quarries are still required because the demand for the stone from the island is still high. This paper presents a review of undertaken geophysical investigations, as well as engineering geologic site prospection, with the purpose of determining if the rock mass quality is suitable for the mining of massive blocks needed for an architectural purpose—dimension stones. Several surface noninvasive geophysical methods were applied on the site, comprising of two seismic methods, multichannel analysis of surface waves (MASW) and shallow refraction seismic (SRS) electrical methods of electrical resistivity tomography (ERT), as well as electromagnetic exploration with ground penetrating radar (GPR). Results of geophysical investigations were compared to the engineering geologic prospection results, as well to the visible rock mass structure and observed discontinuities on the neighboring existing open mine quarry. Rock mass was classified into three categories according to its suitability for dimension stone exploitation. Each category is defined by compressional and shear seismic velocities as well as electrical resistivity. It has been found that even small changes in moisture content within the large monolithic rock mass can influence measured values of electrical resistivity. In the investigated area, dimension stone quarrying is advisable if the rock mass has values of resistivity higher than 3000 Ωm, as well as compressional seismic velocities higher than 3000 m/s and shear wave velocities higher than 1500 m/s. Georadar was found to be a good tool for the visual determination of fissured systems, and was used to confirm findings from other geophysical methods.

Geomechanical safety assessment for transversely isotropic rock mass subjected to deep mining operations

2015 ◽  
Vol 52 (10) ◽  
pp. 1477-1489 ◽  
Author(s):  
W. Pytel ◽  
B. Pałac-Walko
Keyword(s):  
Rock Mass ◽  
Focal Mechanism ◽  
Geophysical Methods ◽  
Safety Margin ◽  
Main Roof ◽  
High Energy ◽  
Anisotropic Rock ◽  
Mining Operations ◽  
Safety Level ◽  
Transversely Isotropic Rock

The largest risk for mining operations conducted within the Legnica–Głogów Copper Basin is created mostly by high-energy tremors, the hypocenters of which are located within the main roof strata composed of sedimentary-type rocks — mainly dolomite and anhydrite — about 40–200 m above the excavated copper ore body. These categories of rock clearly exhibit anisotropic strength–deformation characteristics that may significantly affect the safety level value represented by the appropriate safety margin (or safety factor) based on an adequate strength hypothesis. As the focal mechanism most often encountered in such tremors is a slipping-type mechanism with a rupture plane, typically the Mohr–Coulomb theory of strength is applied for a safety level assessment in Polish copper mines. It has been assumed, however, that strength theories based on anisotropic failure criteria should serve as better indicators of correlation between observed and well-characterized sedimentary rock strata failure mechanisms and the location of concentrated areas of the negative values of margin of safety within the rock mass. As changing levels of stress in the rock mass during the mining process may be tracked effectively using solutions offered by appropriate three-dimensional geomechanical models (e.g., finite element method), the assessment of these changes due to mining-face progress is also possible in the location where the seismic tremor occurred. This assessment is characterized by its focal mechanism using the appropriate geophysical methods that permit finding such geomechanical conditions, engaging also the rock mass’ strain–stress states and the material anisotropic characteristics. On the basis of the long-term path of rock mass loading — due to mining predicted by numerical modeling — this could indicate the necessary conditions that should be fulfilled if the anticipated methods of the geophysics failure mechanism could be developed. This is particularly important for anisotropic rock structures. The proposed approach is illustrated using an example of a strong seismic energy event of 0.22 GJ that occurred in 2005 in an area of the Rudna mine.

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