scholarly journals Determination of the stability of residual pillars in a room-and-pillar mining goaf under eccentric load

2021 ◽  
Vol 7 ◽  
pp. 9122-9132
Author(s):  
Nan Zhou ◽  
Erbao Du ◽  
Meng Li ◽  
Jixiong Zhang ◽  
Chaowei Dong
Keyword(s):  
Eccentric Load ◽  
Room And Pillar Mining ◽  
Pillar Mining ◽  
The Stability

Optimization of Stope Structural Parameters in Phosphorite Mine and its Stability Analysis

2014 ◽  
Vol 580-583 ◽  
pp. 1268-1272 ◽  
Author(s):  
Xiang Xing Li ◽  
Ke Gang Li
Keyword(s):  
Structural Parameters ◽  
Simulation Method ◽  
Surrounding Rock ◽  
Room And Pillar Mining ◽  
Rock Stability ◽  
Mining Depth ◽  
Ground Pressure ◽  
Pillar Mining ◽  
Phosphate Deposit ◽  
The Stability

A mine plans to exploit the low dip thin phosphate deposit by room-and-pillar mining. But a township highway is just above the orebody, and its distance is only 80m, in order to better control the ground pressure in stopes and ensure the operation security, the size of room and pillar must be reasonably designed to maintain the stability of stopes and surrounding rock. The 3D-σ numerical simulation method was applied to analyze the surrounding rock stability in different stope structure parameters. The results show that when holding the size of pointed prop unchanged, the surrounding rock stability would decline with the increase of room width and pillar spacing, for security, the mining plan, the pointed prop is 3×3 m, the stope width and pillar spacing is not more than 9 m, were considered to be one of the optimal. In addition, it is important to emphasize that if the mining depth exceeds 300m, some methods, such as decreasing the spacing of stope and pointed props or increasing the pillar size, need to be taken to avoid the stope instability caused by greater ground pressure.

scholarly journals LONG-TERM STABILITY MONITORING OF THE MINING BLOCKS IN ESTONIAN OIL SHALE MINES

2006 ◽  
Vol 1 ◽  
pp. 206
Author(s):  
J.-R. Pastarus
Keyword(s):  
Influence Factors ◽  
Monitoring Methods ◽  
Mining System ◽  
Term Stability ◽  
Long Term Stability ◽  
Room And Pillar Mining ◽  
Convergence Method ◽  
Pillar Mining

This paper deals with long-term stability prediction and monitoring methods by room-and-pillar mining system. Roof-to-floor convergence and conditional thickness methods suit for calculations. They allow determination of the location, area and time of the collapse in a mining block. The uncertainty in time is less than 10 % at the 95 % confidence level. Roof-to-floor convergence method is preferred; it takes into consideration all the geological and mining feature in the critical area. Conditional thickness method demands supplementary investigations, determination of the influence factors on the process. The applicability of these methods is clearly demonstrated.

scholarly journals DETERMINATION OF DEFORMATION PROPERTIES AND NATURAL STRESSES IN ROCK MASS BY UNDERGROUND GEODESY DATA

2021 ◽  
Vol 2 (4) ◽  
pp. 52-61
Author(s):  
Anton V. Panov ◽  
Leonid A. Nazarov
Keyword(s):  
Inverse Problem ◽  
Measurement Data ◽  
Domain Size ◽  
Structural Elements ◽  
Room And Pillar Mining ◽  
3D Geomechanical Model ◽  
Deformation Properties ◽  
Pillar Mining ◽  
Typical Configuration

The authors have developed and implemented a 3D geomechanical model using the finite element method for a typical configuration of an underground space during room-and-pillar mining. The authors formulate and solve an inverse problem on determination of values and orientation of external horizontal stresses and deformation characteristics of structural elements of the geotechnology by the measurement data of sidewall convergence in rooms in the course of mining. The level curves of different objective functions are analyzed, the mixed inverse problem resolvability is demonstrated, and the equivalence domain size is correlated with the relative error of input data.

scholarly journals METHOD OF ESTIMATION OF RHEOLOGICAL CHARACTERISTICS OF ROCK MASS USING DATA OF UNDERGROUND GEODESY IN TERMS OF VISCOELASTIC MODEL

2019 ◽  
Vol 2 (4) ◽  
pp. 229-236
Author(s):  
Anton Panov ◽  
Leonid Nazarov ◽  
Nelli Miroshnichenko
Keyword(s):  
Numerical Experiments ◽  
Viscoelastic Model ◽  
Measurement Data ◽  
Mineral Deposits ◽  
Room And Pillar Mining ◽  
Pillar Mining ◽  
Using Data ◽  
Determination Of Parameters

Method of estimation of rheological properties of constructive elements of room-and-pillar mining of solid mineral deposits is considered. The method is based on solution of inverse problems of mixed type in the context of two dimensional viscoelastic model of structure. Feasibility of in situ determination of parameters for constitutive equations describing rheological deformation of rocks is shown. The numerical experiments implemented with synthetic input data (relative displacements recorded at the points of mined-out void boundary using in-mine geodetics techniques) for the preset absolute precision of equipment provide the measurement data amount required to ensure resolvability of inverse problem.

scholarly journals EVALUATION OF THE STABILITY OF A TEMPORARY PILLAR WHEN MIINING ORE HORIZONS WITH BACKFILLING AND CAVING

2021 ◽  
Vol 2 (3) ◽  
pp. 123-134
Author(s):  
Sergey Yu. Vasichev ◽  
Alexander A. Neverov
Keyword(s):  
Raw Materials ◽  
Ore Deposits ◽  
Geomechanical Model ◽  
Mining System ◽  
Room And Pillar Mining ◽  
Mining Front ◽  
Pillar Mining ◽  
The Stability ◽  
Enclosing Rocks ◽  
Safe Mining

A method is proposed for mining thick and flat ore deposits at great depths in conditions of a decline in the value of extracted mineral raw materials. It is found that safe mining with solidifying backfill and caving is achieved by determining the parameters of stable spans of rooms, in place of which artificial supports and temporary ore pillars are formed. These pillars are recovered with a lag behind room-and-pillar mining by caving of ore and enclosing rocks. It is shown that, depending on the type of geomechanical model of geomedium and orientation of the initial natural stresses acting in the rock mass relative to the mining front, the field of application of the mining system is limited by the depth and parameters of excavation. Predictive areas of possible rock failure are determined applicably to rock masses with different degree of disturbance.

Determining the Norton’s Equivalent Model of Distribution System with Distributed Generation (DG) for Stability Analysis

2019 ◽  
Vol 12 (2) ◽  
pp. 190-198
Author(s):  
Sunny Katyara ◽  
Lukasz Staszewski ◽  
Faheem Akhtar Chachar
Keyword(s):  
Distributed Generation ◽  
Normal Condition ◽  
Distribution System ◽  
Distribution Networks ◽  
Equivalent Model ◽  
Stability Factor ◽  
Matlab Simulation ◽  
The Stability ◽  
Stability Issues

Background: Since the distribution networks are passive until Distributed Generation (DG) is not being installed into them, the stability issues occur in the distribution system after the integration of DG. Methods: In order to assure the simplicity during the calculations, many approximations have been proposed for finding the system’s parameters i.e. Voltage, active and reactive powers and load angle, more efficiently and accurately. This research presents an algorithm for finding the Norton’s equivalent model of distribution system with DG, considering from receiving end. Norton’s model of distribution system can be determined either from its complete configuration or through an algorithm using system’s voltage and current profiles. The algorithm involves the determination of derivative of apparent power against the current (dS/dIL) of the system. Results: This work also verifies the accuracy of proposed algorithm according to the relative variations in the phase angle of system’s impedance. This research also considers the varying states of distribution system due to switching in and out of DG and therefore Norton’s model needs to be updated accordingly. Conclusion: The efficacy of the proposed algorithm is verified through MATLAB simulation results under two scenarios, (i) normal condition and (ii) faulty condition. During normal condition, the stability factor near to 1 and change in dS/dIL was near to 0 while during fault condition, the stability factor was higher than 1 and the value of dS/dIL was away from 0.

Synthesis and solvatochromic studies of 2- amino-3-phenolazo1-(4-sulfophenyl)-3-methyi-5-pyrozolone and use it for the determination of trace amount of Nickel (II) in blood samples

2016 ◽  
Vol 5 (10) ◽  
pp. 4920
Author(s):  
Amar M. Ali ◽  
Hussain. J. Mohammed*
Keyword(s):  
Stability Constant ◽  
Trace Amount ◽  
Benzenesulfonic Acid ◽  
Determination Method ◽  
Blood Samples ◽  
Determination Of Nickel ◽  
Normal Human ◽  
The Stability ◽  
Normal Human Blood

A new, simple, sensitive and rapid spectrophotometric method is proposed for the determination of trace amount of Nickel (II). The method is based on the formation of a 1:2 complex with 4-(4-((2-hydroxy-6-nitrophenyl) diazenyl) -3-methyl-5-oxo-2, 5-dihydro-1H-pyrazol-1-yl) benzenesulfonic acid (2-ANASP) as a new reagent is developed. The complex has a maximum absorption at 516 nm and εmax of 1. 84 X 105 L. mol-1. cm-1. A linear correlation (0. 25 – 4. 0μg. ml-1) was found between absorbance at λmax and concentration. The accuracy and reproducibility of the determination method for various known amounts of Nickel (II) were tested. The results obtained are both precise (RSD was 1. 2 %) and accurate (relative error was 0. 787 %). The effect of diverse ions on the determination of Nickel (II) to investigate the selectivity of the method were also studied. The stability constant of the product was 0. 399 X 106 L. mol-1. The proposed method was successfully applied to the analysis of diabetes blood and normal human blood. 

scholarly journals Determination of Objective Weights Using a New Method Based on the Removal Effects of Criteria (MEREC)

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 525 ◽  
Author(s):  
Mehdi Keshavarz-Ghorabaee ◽  
Maghsoud Amiri ◽  
Edmundas Kazimieras Zavadskas ◽  
Zenonas Turskis ◽  
Jurgita Antucheviciene
Keyword(s):  
Essential Elements ◽  
New Method ◽  
Multi Criteria Decision Making ◽  
Analysis Of Means ◽  
Simulation Based ◽  
Criteria Weights ◽  
The Stability ◽  
Computational Analyses ◽  
Weighting Methods

The weights of criteria in multi-criteria decision-making (MCDM) problems are essential elements that can significantly affect the results. Accordingly, researchers developed and presented several methods to determine criteria weights. Weighting methods could be objective, subjective, and integrated. This study introduces a new method, called MEREC (MEthod based on the Removal Effects of Criteria), to determine criteria’ objective weights. This method uses a novel idea for weighting criteria. After systematically introducing the method, we present some computational analyses to confirm the efficiency of the MEREC. Firstly, an illustrative example demonstrates the procedure of the MEREC for calculation of the weights of criteria. Secondly, a comparative analysis is presented through an example for validation of the introduced method’s results. Additionally, we perform a simulation-based analysis to verify the reliability of MEREC and the stability of its results. The data of the MCDM problems generated for making this analysis follow a prevalent symmetric distribution (normal distribution). We compare the results of the MEREC with some other objective weighting methods in this analysis, and the analysis of means (ANOM) for variances shows the stability of its results. The conducted analyses demonstrate that the MEREC is efficient to determine objective weights of criteria.

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