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 Rock Mass Rating and Geological Strength Index of rock masses of Thopal-Malekhu River areas, Central Nepal Lesser Himalaya

2013 ◽  
Vol 16 ◽  
pp. 29-42 ◽  
Author(s):  
Jaya Laxmi Singh ◽  
Naresh Kazi Tamrakar
Keyword(s):  
Rock Mass ◽  
Surface Condition ◽  
Geological Strength Index ◽  
Rock Mass Rating ◽  
Rock Slopes ◽  
Lesser Himalaya ◽  
Rock Masses ◽  
Strength Index ◽  
Rock Mass Structure ◽  
Exposed Rock

The rock slopes of the Thopal-Malekhu River areas, Lesser Himalaya, were characterized applying various systems of rock mass classification, such as Rock mass Rating (RMR) and Geological Strength Index (GSI), because the study area comprises well exposed rock formations of the Nawakot and Kathmandu Complexes, across the Thopal-Malekhu River areas. In RMR system, mainly five parameters viz. Uniaxial Compressive Strength (UCS) of rock, Rock Quality Designation (RQD), spacing of discontinuity, condition of discontinuity, and groundwater condition were considered. The new GSI charts, which were suitable for schistose and much disintegrated rock masses, were used to characterize rock slopes based on quantitative analysis of the rock mass structure and surface condition of discontinuities. RMR ranged from 36 to 82 (poor to very good rock mass) and GSI from 13.5±3 to 58±3 (poor to good rock mass). Slates (of the Benighat Slate) are poor rock masses with low strength, very poor RQD, and close to very close spacing of discontinuity, and dolomites (Dhading Dolomite) are fair rocks with disintegrated, poorly interlocked, and heavily broken rock masses yielding very low RMR and GSI values. Phyllites (Dandagaun Phyllite), schist (Robang Formation) and quartzite (Fagfog Quartzite, Robang Formation and Chisapani Quartzite), dolomite (Malekhu Limestone), and metasandstone (Tistung Formation) are fair rock masses with moderate GSI and RMR values, whereas quartzose schist and gneiss (Kulekhani Formation) are very good rock masses having comparatively higher RMR and GSI. The relationship between GSI and RMR shows positive and good degree of correlation. DOI: http://dx.doi.org/10.3126/bdg.v16i0.8882   Bulletin of the Department of Geology Vol. 16, 2013, pp. 29-42

Empirical-Statical-Dynamical (ESD) Methodology for Extrapolation of Rock Mass Properties for Construction of Tunnels

2015 ◽  
Vol 725-726 ◽  
pp. 349-354 ◽  
Author(s):  
Zlatko Zafirovski ◽  
Nikolay Vatin
Keyword(s):  
Rock Mass ◽  
Rock Mass Classification ◽  
Rock Masses ◽  
Rock Mass Properties ◽  
Engineering Structures ◽  
Rock Mass Structure ◽  
Mass Properties ◽  
Mass Classification ◽  
Definition Of

The investigation in rock masses in interaction with engineering structures is extremely important in a process of design of tunnels. The main problem is how to extrapolate the parameter from the zone of testing to the whole volume that is of interes for interaction analyses of the system rock mass-structure. In this article Empirical-Statical-Dynamical (ESD) methodology of extrapolation is presented. The basis of the methodology lies in combination of the results from geotechnical and geophysical testings and rock mass classification, connected with definition of adequate regressive models.

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.

scholarly journals Methodology of modeling nonlinear geomechanical processes in blocky and layered rock masses on models made of equivalent materials

2021 ◽  
Vol 250 ◽  
pp. 542-552
Author(s):  
Boris Zuev
Keyword(s):  
Rock Mass ◽  
Underground Mining ◽  
Similarity Criterion ◽  
Nonlinear Problems ◽  
Rock Masses ◽  
Mining Operations ◽  
Initial Field ◽  
Reliable Determination ◽  
Nonlinear Geomechanical Processes

The research purpose is to develop a methodology that increases the reliability of reproduction and research on models made of equivalent materials of complex nonlinear processes of deformation and destruction of structured rock masses under the influence of underground mining operations to provide a more accurate prediction of the occurrence of dangerous phenomena and assessment of their consequences. New approaches to similarity criterion based on the fundamental laws of thermodynamics; new types of equivalent materials that meet these criteria; systems for the formation of various initial and boundary conditions regulated by specially developed computer programs; new technical means for more reliable determination of stresses in models; new methods for solving inverse geomechanical problems in the absence of the necessary initial field data have been developed. Using the developed methodology, a number of complex nonlinear problems have been solved related to estimates of the oscillatory nature of changes in the bearing pressure during dynamic roof collapse processes; ranges of changes in the frequency of processes during deformation and destruction of rock mass elements, ranges of changes in their accelerations; parameters of shifts with a violation of the continuity of the rock mass under the influence of mining: secant cracks, delaminations, gaping voids, accounting for which is necessary to assess the danger of the formation of continuous water supply canals in the water-protection layer.

Numerical Modelling and Assessment of Excavation Damaged Zone around the Underground Excavations: A Case Study

2006 ◽  
Vol 324-325 ◽  
pp. 77-80 ◽  
Author(s):  
Deng Pan Qiao ◽  
Zong Sheng Zhang ◽  
Shu Hong Wang ◽  
Ya Bin Zhang
Keyword(s):  
Rock Mass ◽  
Stress Field ◽  
Numerical Modelling ◽  
Underground Mining ◽  
Rock Masses ◽  
Stress Concentrations ◽  
Anisotropic Rock ◽  
Excavation Damaged Zone ◽  
Damaged Zone

This paper presents a study on the quantification of the degree of damage from the microseismic event data, for assessment of excavation damaged zone of anisotropic rock in Jinchuan mine and presents numerical simulation and prediction on the deformation and failure of the rock masses surrounding laneway under rock mass properties and excavating conditions. Following an introduction to the engineering geology and mechanical properties of the rock mass in the Jinchuan mine areas, this paper reveals the features of the measured in situ stresses and puts emphasis on an analysis of the mechanism of underground opening and damage induced by the underground mining. Stress and AE redistribution induced by excavation of underground engineering results in the unloading zone in parts of surrounding rock masses. A micromechanics-based model has been proposed for brittle rock material undergoing irreversible changes of their microscopic structures due to microcrack growth. A systematical numerical modeling analysis method was completed. Based on numerical modelling, a series of predicting curves for rock mass response and deformation are obtained, which provides the basis of guiding the design and construction of anisotropic rock cave in Jinchuan mine. The use of the in situ stress field results in enhanced modeling of the stress concentrations and potential failures at the mines has also been reviewed. Knowledge of the prevailing rock stress field at the mines is a critical component for such modeling which has led to improved rock mechanics understanding and operations at Jinchuan mines.

The Failure and Falling of the Rock Mass in the Underground Mining

2005 ◽  
Vol 297-300 ◽  
pp. 2586-2591 ◽  
Author(s):  
Wen Zhao ◽  
Shiyue Wu ◽  
Wan Cheng Zhu
Keyword(s):  
Rock Mass ◽  
Underground Mining ◽  
Failure Process ◽  
Underground Mine ◽  
Rock Masses ◽  
Load Carrying ◽  
Iron Mine ◽  
The Stability ◽  
Theory Research

In this paper, the process of failure and falling of the rock masses in the underground mining is studied; and the relationship between the processes of failure and falling of rock masses is proposed based on the rockmass strength theory. Research indicates that the failures of the rock and rock masses are probably not at all in common. Even though the rock masses go into the plastic condition, even to the extent that come into being in the failure, they do not surely fall. Hence, the mechanical properties of rock mass, especially after the failure, still need to be further researched. The laneway and the stope in the mining engineering are the temporary engineering, the load- carrying ability of the rock masses should be bought into play as far as possible, and therefore the stabilization during failure process is a significant for the supporting in the underground mine under safety prerequisite. Since 1 million m3 of the mined-out area is formed by mine for many year at Xishimen iron mine in China, and the gob roof is only 54m from the ground, the mined-out area is potentially dangerous to the underground mine. This paper analyzes the pattern of the stability and falling process in the mined-out area based on the theoretical analysis and numerical calculation, in order to obtains the falling criterion of the roof rock masses and stabilize the mined-out area. The predicted falling shape and range of the mined-out area is compared well with the in-situ observations. This contribution has also been popularized in many mines of China.

Radon Anomaly Analysis of Engineering Slopes

2011 ◽  
Vol 261-263 ◽  
pp. 1161-1166
Author(s):  
Xiao Qun Wang
Keyword(s):  
Rock Mass ◽  
Analysis Data ◽  
Scientific Basis ◽  
Stability Study ◽  
Rock Mass Structure ◽  
Complementary Method ◽  
Other Information ◽  
Anomaly Analysis ◽  
Slope Rock ◽  
Radon Content

For various engineering slopes, due to unloading relaxation of the rock mass or sliding disintegration of the slope, the cracks inside the slope will open by different extent, thus when measuring radon content, different parts of the slope will have different radon content anomaly. Through analyzing radon content anomaly, information as the landslide boundary and structure zoning of the slope rock mass, etc can be obtained. Landslide boundaries and rock mass structure zoning and other information can be identified because of radon anomalies analysis. Through radon anomalies analysis on two projects, landslide boundary identification and zoning on bank-slope adit rock mass structure, it has proved that radon anomalies analysis could be well used as a complementary method to provide more analysis data and thus provide objective scientific basis for slope stability study. The analysis method used is simple, easy to operate, and low in cost. In the analysis, it shall be noted that removing interference from groundwater, desiccant humidity should be excluded.

THE IDENTIFICATION OF PARAMETERS OF THEORIES USED FOR PROGNOSES OF POST MINING DEFORMATIONS BY MEANS OF PRESENT SOFTWARE / IDENTYFIKACJA WARTOŚCI PARAMETRÓW TEORII PROGNOZOWANIA WPŁYWÓW PRZY WYKORZYSTANIU WSPÓŁCZESNYCH NARZĘDZI INFORMATYCZNYCH

2013 ◽  
Vol 58 (4) ◽  
pp. 1347-1357 ◽  
Author(s):  
Roman Ścigała
Keyword(s):  
Rock Mass ◽  
Land Surface ◽  
Underground Mining ◽  
Transient State ◽  
Computer Programs ◽  
Asymptotic State ◽  
Software System ◽  
Practical Utilization ◽  
Identification Of Parameters ◽  
Graphical Processing

Abstract The characteristic of specialized computer programs has been presented, serving for identification of W. Budryk-S. Knothe theory parameters, used for description of asymptotic state of post-mining deformations, as well as for transient state. The software is the result of several years of authors’ work. It is a part of complete software system designed for forecasting of underground mining influences on the rock mass and land surface and graphical processing of calculations results. Apart from software description, a short example of its practical utilization has been attached.

Analysis of Unstable Rock-Mass Stability Based on Limit Equilibrium Method and Strength Reduction Method

2016 ◽  
Vol 858 ◽  
pp. 73-80
Author(s):  
Ying Kong ◽  
Hua Peng Shi ◽  
Hong Ming Yu
Keyword(s):  
Rock Mass ◽  
Failure Mode ◽  
Posterior Margin ◽  
Reduction Method ◽  
Limit Equilibrium ◽  
Limit Equilibrium Method ◽  
Strength Reduction ◽  
Strength Reduction Method ◽  
Rock Masses ◽  
Unstable Rock

With the slope unstable rock masses of a stope in Longsi mine, Jiaozuo City, China as the target, we computed and analyzed the stability of unstable rock masses using a limit equilibrium method (LEM) and a discrete element strength reduction method (SRM). Results show that the unstable rock masses are currently stable. Under the external actions of natural weathering, rainfall and earthquake, unstable rock mass 1 was manifested as a shear slip failure mode, and its stability was controlled jointly by bedding-plane and posterior-margin steep inclined joints. In comparison, unstable rock mass 2 was manifested as a tensile-crack toppling failure mode, and its stability was controlled by the perforation of posterior-margin joints. From the results of the 2 methods we find the safety factor determined from SRM is larger, but not significantly, than that from LEM, and SRM can simulate the progressive failure process of unstable rock masses. SRM also provides information about forces and deformation (e.g. stress-strain, and displacement) and more efficiently visualizes the parts at the slope that are susceptible to instability, suggesting SRM can be used as a supplementation of LEM.

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