scholarly journals Linking Stability Conditions and Ore Dilution in Open Stope Mining

2021 ◽  
Vol 5 (1) ◽  
pp. 34
Author(s):  
Andreas Delentas ◽  
Andreas Benardos ◽  
Pavlos Nomikos
Keyword(s):  
Cost Effectiveness ◽  
Numerical Analysis ◽  
Optimal Design ◽  
Early Identification ◽  
Stability Conditions ◽  
Mathematical Expressions ◽  
The Stability ◽  
Stability Graph ◽  
Empirical Approaches ◽  
Key Parameter

The estimation of the stability conditions, over-breaks, and spalling failures, which could inflict potential external dilution, is a key parameter so as to ensure the optimal design of the exploitation and its cost effectiveness The research undertaken aims at correlating established empirical approaches for the estimation of the stability condition with numerical analysis that identifies and measures the depth of failure. A number of analyses have been conducted and the results obtained yield promising results that can be transformed to direct mathematical expressions applied for the early estimation of dilution rates. Furthermore, through the research, an initial proposal is made for a dilution-based stability graph that could be utilized for the early identification of dilution.

scholarly journals Analyzing Stability Conditions and Ore Dilution in Open Stope Mining

Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1404
Author(s):  
Andreas Delentas ◽  
Andreas Benardos ◽  
Pavlos Nomikos
Keyword(s):  
Production Process ◽  
Underground Mining ◽  
Fundamental Problem ◽  
Numerical Models ◽  
Simulation Models ◽  
Stability Conditions ◽  
Mining Operations ◽  
Design Characteristics ◽  
The Stability ◽  
Stability Graph

Ore dilution is a fundamental problem for the production process in underground mining operations. Especially in open stoping methods of underground mining, the continuous estimation, monitoring and treatment of instability issues is considered necessary in order to maintain the consistency of the production process. This paper aims to combine empirical nomograms of stability estimation and numerical approaches and thus link the extensive experiences of the empirical design and the quantitative data derived by numerical analyses. To facilitate this, a large number of different geomechanical conditions were modeled and analyzed in the pursuit of obtaining valid and applicable relationships between the empirical stability graphs’ approaches and the numerical simulation models. The parametric analysis was made to express the stability conditions and the dilution with specific design characteristics, using prevalent stability-graph approaches while the numerical models were tested using the RS2 software package. The obtained results include direct and easy-to-use mathematical expressions that can be applied during the initial design of the stoping process, especially for the case of sidewalls (hanging walls and foot walls). Furthermore, through the research, an initial proposal is made for a dilution-based stability graph that could be utilized for the early identification of dilution.

scholarly journals A Feasibility Study on The Implementation of Neural Network Classifiers for Open Stope Design

2021 ◽  
Author(s):  
Amoussou Coffi Adoko ◽  
Festus Saadaari ◽  
Daniel Mireku-Gyimah ◽  
Askar Imashev
Keyword(s):  
Neural Network ◽  
Stability Conditions ◽  
Feed Forward Neural Network ◽  
Graph Method ◽  
Average Accuracy ◽  
Artificial Neural Network Ann ◽  
Neural Network Classifiers ◽  
The Stability ◽  
Stability Graph ◽  
Stope Design

AbstractAssessing the stability of stopes is essential in open stope mine design as unstable hangingwalls and footwalls lead to sloughing, unplanned stope dilution, and safety concerns compromising the profitability of the mine. Over the past few decades, numerous empirical tools have been developed to dimension open stope in connection with its stability, using the stability graph method. However, one of the principal limitations of the stability graph method is to objectively determine the boundary of the stability zones, and gain a clear probabilistic interpretation of the graph. To overcome this issue, this paper aims to explore the feasibility of artificial neural network (ANN) based classifiers for the design of open stopes. A stope stability database was compiled and included the stope dimensions, rock mass properties, and the stope stability conditions. The main parameters included the modified stability number (N’), and the stope stability conditions (stable, unstable, and failed), and hydraulic radius (HR). A feed-forward neural network (FFNN) classifier containing two hidden layers (110 neurons each) was employed to identify the stope stability conditions. Overall, the outcome of the analysis showed good agreement with the field data; most stope surfaces were correctly predicted with an average accuracy of 91%. This shows an improvement over using the existing stability graph method. In addition, for a better interpretation of the results, the associated probability of occurrence of stable, unstable, or caved stope was determined and shown in iso-probability contour charts which were compared with the stability graph. The proposed FFNN-based classifier outperformed the conventional stability graph method in terms of accuracy and better prabablistic interpretation. It is suggested that the classifier could be a reliable tool that can complement the conventional stability graph for the design of open stopes.

scholarly journals Causality and stability conditions of a conformal charged fluid

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Farid Taghinavaz
Keyword(s):  
Chemical Potential ◽  
Second Law Of Thermodynamics ◽  
Dense Medium ◽  
Wave Number ◽  
Second Law ◽  
Stability Conditions ◽  
Charged Fluid ◽  
Large Wave ◽  
The Stability ◽  
Large Wave Number

Abstract In this paper, I study the conditions imposed on a normal charged fluid so that the causality and stability criteria hold for this fluid. I adopt the newly developed General Frame (GF) notion in the relativistic hydrodynamics framework which states that hydrodynamic frames have to be fixed after applying the stability and causality conditions. To do this, I take a charged conformal matter in the flat and 3 + 1 dimension to analyze better these conditions. The causality condition is applied by looking to the asymptotic velocity of sound hydro modes at the large wave number limit and stability conditions are imposed by looking to the imaginary parts of hydro modes as well as the Routh-Hurwitz criteria. By fixing some of the transports, the suitable spaces for other ones are derived. I observe that in a dense medium having a finite U(1) charge with chemical potential μ0, negative values for transports appear and the second law of thermodynamics has not ruled out the existence of such values. Sign of scalar transports are not limited by any constraints and just a combination of vector transports is limited by the second law of thermodynamic. Also numerically it is proved that the most favorable region for transports $$ {\tilde{\upgamma}}_{1,2}, $$ γ ˜ 1 , 2 , coefficients of the dissipative terms of the current, is of negative values.

scholarly journals Iterative stability analysis for general polynomial control systems

2021 ◽  
Author(s):  
Bo Xiao ◽  
Hak-Keung Lam ◽  
Zhixiong Zhong
Keyword(s):  
Stability Analysis ◽  
Lyapunov Function ◽  
Control Systems ◽  
Polynomial System ◽  
Stability Conditions ◽  
General Polynomial ◽  
Main Challenge ◽  
Detailed Simulation ◽  
Feasible Solutions ◽  
The Stability

AbstractThe main challenge of the stability analysis for general polynomial control systems is that non-convex terms exist in the stability conditions, which hinders solving the stability conditions numerically. Most approaches in the literature impose constraints on the Lyapunov function candidates or the non-convex related terms to circumvent this problem. Motivated by this difficulty, in this paper, we confront the non-convex problem directly and present an iterative stability analysis to address the long-standing problem in general polynomial control systems. Different from the existing methods, no constraints are imposed on the polynomial Lyapunov function candidates. Therefore, the limitations on the Lyapunov function candidate and non-convex terms are eliminated from the proposed analysis, which makes the proposed method more general than the state-of-the-art. In the proposed approach, the stability for the general polynomial model is analyzed and the original non-convex stability conditions are developed. To solve the non-convex stability conditions through the sum-of-squares programming, the iterative stability analysis is presented. The feasible solutions are verified by the original non-convex stability conditions to guarantee the asymptotic stability of the general polynomial system. The detailed simulation example is provided to verify the effectiveness of the proposed approach. The simulation results show that the proposed approach is more capable to find feasible solutions for the general polynomial control systems when compared with the existing ones.

Optimal Design of the Large-Diameter Spinning Torispherical Head

2012 ◽  
Vol 544 ◽  
pp. 194-199
Author(s):  
Di Zhang ◽  
Shui Ping Sheng ◽  
Zeng Liang Gao
Keyword(s):  
Finite Element ◽  
Optimal Design ◽  
Large Diameter ◽  
General Purpose ◽  
Design Tool ◽  
Crown Area ◽  
Finite Element Software ◽  
The Stability

Two important parameters of torispherical head that are (interior radius of spherical crown area) and r (interior radius of transition corner) have been optimized by the module of the large general-purpose finite-element software ANSYS, targeting the strength and stability of the head. This paper provides an optimized torispherical head, which improves the stability of the edge of the head with acceptable strength of the head. The procedure is generally applicable as a design tool for optimal design.

The Optimum Quality Index for the Stability of In-Parallel Planar Platform Devices

1999 ◽  
Vol 121 (1) ◽  
pp. 15-20 ◽  
Author(s):  
J. Lee ◽  
J. Duffy ◽  
M. Keler
Keyword(s):  
Optimal Design ◽  
Equilateral Triangle ◽  
Quality Index ◽  
Optimal Shape ◽  
Geometrical Meaning ◽  
Moving Platforms ◽  
Maximum Value ◽  
Dimensionless Ratio ◽  
Parallel Platform ◽  
The Stability

The paper investigates primarily the geometrical meaning of the determinant of the Jacobian (det j) of the three connector lines of a planar in-parallel platform device using reciprocity. A remarkably simple result is deduced: The maximum value of det j namely, det jm is simply one-half of the sum of the lengths of the sides of the moving triangular platform. Further, this result is shown to be independent of the location of the fixed pivots in the base. A dimensionless ratio λ = |det j|/det jm is defined as the quality index (0 ≤ λ ≤ 1) and it is proposed here to use it to measure “closeness” to a singularity. An example which determines the optimal design by comparing different shaped moving platforms having the same det jm is given and demonstrates that the optimal shape is in fact an equilateral triangle

scholarly journals Mineralogical stabilization of Ternesite in Belite Sulfo-Aluminate Clinker elaborated from limestone, shale and phosphogypsum

2018 ◽  
Vol 149 ◽  
pp. 01073
Author(s):  
K. Ben Addi ◽  
A. Diouri ◽  
N. Khachani ◽  
A. Boukhari
Keyword(s):  
Infrared Spectroscopy ◽  
Phosphoric Acid ◽  
Portland Cement ◽  
Stability Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Stability

This paper investigates the mineralogical evolution of sulfoaluminate clinker elaborated from moroccan prime materials limestone, shale and phosphogypsum as a byproduct from phosphoric acid factories. The advantage of the production of this type of clinker is related to the low clinkerisation temperature which is known around 1250°C, and to less consumption quantity of limestone thus enabling less CO2 emissions during the decarbonation process compared to that of Portland cement. In this study we determine the stability conditions of belite sulfoaluminate clinker containing belite (C2S) ye’elimite (C4A3$) and ternesite (C5S2$). The hydration compounds of this clinker are also investigated. The monitoring of the synthesized and hydrated phases is performed by X-Ray Diffraction and Infrared spectroscopy. The results show the formation of ternesite at 800°C and the stabilization of clinker containing y’elminite, belite and ternesite at temperatures between 1100 and 1250°C.

scholarly journals An integral equation formulation of the N-body dielectric spheres problem. Part 1: Numerical analysis

2020 ◽  
Author(s):  
Muhammad Hassan ◽  
Benjamin Stamm
Keyword(s):  
Integral Equation ◽  
Numerical Analysis ◽  
Error Analysis ◽  
Convergence Rates ◽  
A Priori ◽  
Approximation Error ◽  
Spherical Particles ◽  
Integral Equation Formulation ◽  
Dielectric Spheres ◽  
The Stability

In this article, we analyse an integral equation of the second kind that represents the solution of N interacting dielectric spherical particles undergoing mutual polarisation. A traditional analysis can not quantify the scaling of the stability constants- and thus the approximation error- with respect to the number N of involved dielectric spheres. We develop a new a priori error analysis that demonstrates N-independent stability of the continuous and discrete formulations of the integral equation. Consequently, we obtain convergence rates that are independent of N.

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