Likelihood statistic for interpretation of the stability graph for open stope design

Abstract The stability graph method of stope design is one of the most widely used methods of stability assessments of stopes in underground polymetallic mines. The primary objective of this work is to introduce a new stability chart, which includes all relevant case histories, and to exclude parameters with uncertainties in the determination of stability number. The modified stability number was used to achieve this goal, and the Extended Mathews database was recalculated and compared with the new stability graph. In this study, a new refined Consolidated stability graph was developed by excluding the entry mining methods data from the Extended graph data, and only the non-entry methods data was used. The applicability of the proposed Consolidated stability chart was demonstrated by an open stope example. The stability for each stope surface was evaluated by a probabilistic approach employing a logistic regression model and the developed Consolidated stability chart. Comparing the stability analysis results with that of other published works of the same example shows that the determined Consolidated chart, in which the entry-method data is excluded, produces a more conservative and safer design. In conclusion, the size and quality of the dataset dictate the reliability of this approach.

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

Geotechnical and Geological Engineering ◽

10.1007/s10706-021-01915-8 ◽

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.

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New rock stress factor for the stability graph method

International Journal of Rock Mechanics and Mining Sciences ◽

10.1016/j.ijrmms.2010.09.015 ◽

2011 ◽

Vol 48 (1) ◽

pp. 141-145 ◽

Cited By ~ 12

Author(s):

Hani S. Mitri ◽

Rory Hughes ◽

Yaohua Zhang

Keyword(s):

Stress Factor ◽

Rock Stress ◽

Graph Method ◽

The Stability ◽

Stability Graph

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Modification of rock stress factor in the stability graph method: a case study at the Alhada Lead-Zinc Mine in Inner Mongolia, China

Bulletin of Engineering Geology and the Environment ◽

10.1007/s10064-020-01753-7 ◽

2020 ◽

Vol 79 (6) ◽

pp. 3257-3269

Author(s):

Hanwen Jia ◽

Kai Guan ◽

Wancheng Zhu ◽

Honglei Liu ◽

Xige Liu

Keyword(s):

Inner Mongolia ◽

Stress Factor ◽

Rock Stress ◽

Graph Method ◽

Lead Zinc ◽

Zinc Mine ◽

The Stability ◽

Stability Graph

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Development of a generalised dilution-based stability graph for open stope design

Mining Technology ◽

10.1080/14749009.2015.1131940 ◽

2016 ◽

Vol 125 (2) ◽

pp. 121-128 ◽

Cited By ~ 6

Author(s):

A. Papaioanou ◽

F. T. Suorineni

Keyword(s):

Stability Graph ◽

Stope Design

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Stability analysis of underground water-sealed oil storage caverns in China：A case study

Energy Exploration & Exploitation ◽

10.1177/0144598720922307 ◽

2020 ◽

Vol 38 (6) ◽

pp. 2252-2276

Author(s):

Zhao Xingdong ◽

Deng Lei ◽

Zhang Shujing

Keyword(s):

Numerical Simulation ◽

Plastic Zone ◽

Laser Scanning ◽

Underground Water ◽

New Method ◽

3D Laser Scanning ◽

Oil Storage ◽

The Stability ◽

Stability Graph ◽

Q System

The stability of underground water-sealed oil storage caverns is of great importance for safe excavation and operation. To analyze the scope of the failure zone and underground cavern stability accurately, a new method was developed that integrates the rock tunneling quality index Q-system and stability graph method with 3D laser scanning and numerical simulation. The point cloud data were obtained by 3D laser scanning, and the cavern model was built by using DIMINE software, which directly shows the 3D shape of the cavern. The rock mass physical and mechanical parameters and the corresponding stability coefficients were obtained based on Q-system and stability graph method. The plastic zone distribution and deformation characteristics of surrounding rock were analyzed through numerical simulation. Then, the corresponding relationship between caving zone and plastic zone was determined by comparing the numerical simulation results with the 3D laser scanning contour. The new method provides a reliable way to analyze the stability of the underground water-sealed oil storage cavern and also will helpful to design or optimize the subsequent support.

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Stope Stability Assessment and Effect of Horizontal to Vertical Stress Ratio on the Yielding and Relaxation Zones Around Underground Open Stopes Using Empirical and Finite Element Methods

Archives of Mining Sciences ◽

10.1515/amsc-2017-0047 ◽

2017 ◽

Vol 62 (3) ◽

pp. 653-669 ◽

Cited By ~ 5

Author(s):

Mohammadali Sepehri ◽

Derek Apel ◽

Wei Liu

Keyword(s):

Finite Element ◽

Numerical Methods ◽

Stress Ratio ◽

Three Dimensional ◽

Element Model ◽

Underground Mine ◽

Graph Method ◽

The Stability ◽

Stability Graph ◽

The Impact

AbstractPredicting the stability of open stopes can be a challenging task for underground mine engineers. For decades, the stability graph method has been used as the first step of open stope design around the world. However, there are some shortcomings with this method. For instance, the stability graph method does not account for the relaxation zones around the stopes. Another limitation of the stability graph is that this method cannot to be used to evaluate the stability of the stopes with high walls made of backfill materials. However, there are several analytical and numerical methods that can be used to overcome these limitations. In this study, both empirical and numerical methods have been used to assess the stability of an open stope located between mine levels N9225 and N9250 at Diavik diamond underground mine. It was shown that the numerical methods can be used as complementary methods along with other analytical and empirical methods to assess the stability of open stopes. A three dimensional elastoplastic finite element model was constructed using Abaqus software. In this paper a sensitivity analysis was performed to investigate the impact of the stress ratio “k” on the extent of the yielding and relaxation zones around the hangingwall and footwall of the understudy stope.

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Linking Stability Conditions and Ore Dilution in Open Stope Mining

Materials Proceedings ◽

10.3390/materproc2021005034 ◽

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.

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