Statistical and intelligent modeling of underground open stope stability based on the stability graph method

Document Type : Research Article

Authors

1 M.Sc, Petroleum and Geophysics Engineering, Shahrood University of Technology

2 Reasercher, Petroleum and Geophysics Engineering, Shahrood University of Technology.

3 Professor, Faculty of Mining, Petroleum and Geophysics Engineering, Shahrood University of Technology.

Abstract

Summary
This paper presents statistical and intelligent models to predict stability of different surfaces in underground open stope mining method on the basis of the stability graph method. For this purpose, logistic regression and support vector machine were used to predict the stability state of walls and back, separately.
Introduction
The open stope mining method can be considered as the most common method for underground mining of hard rock metal mines around the world. The most common method for the design and evaluation of stopes in the mining technique is the stability graph method which was introduced by Mathews et al. in 1981. The stability graph method is based on data collected from different mines including hydraulic radius, stability number (tunneling modified quality index, rock stress factor, joint adjustment factor, and gravity factor), and related stability conditions. The empirical nature of this method, which results in uncertainties in the values of the parameters, and the existence of different types of charts with different stability regions, interpreting the results becomes a challenge. This increases the risk of error in interpreting the results. In addition to these problems, considering the same conditions for all surfaces, such as walls and back, causes obvious errors in the results of this method. In this regard, this paper incorporated statistical and intelligent methods to predict stability state for a database of open stopes by means of stability graph parameters. The novelty of this paper in addition to the used methods is developing models for evaluation of walls and back separately.
 
Methodology and Approaches
New models to predict the stability state of walls and surface of underground open stopes were developed by using statistical and intelligent techniques. For this purpose, logistic regression (LR), as the most common statistical method for classification, was used. Besides, support vector machine (SVM), which is based on the machine learning theory, was applied as a powerful intelligent technique for classification problems.
 
Results and Conclusions
Results of developed models were compared to those of the stability graph method. The following main conclusions were derived from this study:

The accuracy of back stability prediction by using the stability graph method, LR and SVM were 29%, 86%, and 95%, respectively.
The accuracy of wall stability prediction by using the stability graph method, LR and SVM were 71%, 81%, and 90%, respectively.
In comparison with the stability graph method, LR models of back and walls increase the accuracy of predictions by 57% and 10%, respectively.
In comparison with the stability graph method, SCM models of back and walls increase the accuracy of predictions by 66% and 19%, respectively.

It was concluded that SVM models possess higher performance in the prediction of stable states when compared to the LR models.

Keywords

Main Subjects

Full Text

1-  مقدمه

در اوایل دهه 1980 میلادی بخش بزرگی از صنعت معادن فلزی زیرزمینی، روش استخراج خود را از روش‏های مرسوم نظیر کندن و پرکردن به سمت روش استخراج کارگاه ­باز[i] تغییر دادند. به طوری که بر اساس گزارش‏های سال 1995 حدود 90 درصد معادن فلزی کانادا با این روش استخراج می‌شدند [1].معدن‌کاری کارگاه باز روش معدن‌کاری زیرزمینی توده­ای است که برای استخراج کانسارهای فلزی نسبتاً شیبدار و دارای سنگ­های معدنی و دربرگیرنده با کیفیت خوب مناسب است. کارگاه­های باز عموماً به کارگاه­هایی گفته می­شوند که به طور کلی نیازی به نگهداری ندارند و در آنها فقط به صورت جزئی از ملزومات نگهداری همچون چوب، بولت و غیره استفاده می­شود. همچنین این روش یک روش بدون راهرو است که آن را تبدیل به یکی از ایمن­ترین روش­های معدن‌کاری زیرزمینی کرده‌است [2]. این روش به دو صورت کارگاه باز با چال­های انفجاری عرضی[ii] (شکل 1-الف) و کارگاه باز طولی[iii] (شکل 1-ب) انجام می­شود [3].


[i] Open stope mining

[ii] Transverse Blasthole Open Stoping

[iii] Longitudinal Open Stoping

References

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Journal of Analytical and Numerical Methods in Mining Engineering
Volume 11, Issue 26
April 2021
Pages 47-58

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History

  • Receive Date: 19 May 2020
  • Revise Date: 25 October 2020
  • Accept Date: 26 October 2020

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