Mine Seismology: Seismic Warning Concept: Case Study from Vaal Reefs Gold Mine, South Africa

ISBN-13: 9783319872988 / Angielski / Miękka / 2018 / 201 str.

S. N. Glazer

Spis treści

Preface

Chapter 1 Introduction

References

Chapter 2 Seismicity of the Klerksdorp Goldfields and Resulting Seismic Hazard

2.1 History of Gold Mining in the Klerksdorp Area

2.2 Seismicity in South Africa

2.3 The Klerksdorp Regional Seismic Network

2.4 Severity of Seismic Hazard of the Klerksdorp Goldfields

2.5 Upgrade of the Klerksdorp Regional Seismic Network

2.6 Use of Seismic Data for Calculation of Support Resistance for Rock Burst Conditions at Vaal Reefs

2.7 Summary and Conclusions

References

Chapter 3 Concept of Apparent Stress Index

3.1 Apparent Stress Index and the Energy Index

3.2 Development of the Apparent Stress Index Concept (1991-1992)

3.2.1 Contour Maps of Apparent Stress Index

3.2.2 Contour Maps of Apparent Stress Values

3.3 Examples of Applications of the Stress In

dex Concept (1991-1993)

3.3.1 Back Analysis of a Large Seismic Event that Occurred on 19-06-92 at No. 5 Shaft Vaal Reefs

3.3.2 Interpretation of Seismic Data Recorded in the Vicinity of the Clemcor Dyke from 01-09-91 to 31-09-91

3.3.3 Back Analysis of a Large Seismic Event that Occurred on 19-06-92 at No. 9 Shaft Vaal Reefs

3.3.4 Comparison of Seismicity Between Filled and Conventional Mined Areas

3.3.5 Interpretation Possibilities of the Apparent Stress Index - Some Observations

3.4 Test of the Warning Concept (End of 1993)

3.4.1 Results for Polygon DIKE5#

3.4.2 Results for Polygon HART4

3.4.3 Results for Polygon DUFF1

3.4.4 Summary of the Test

3.5 Future Strategy for Seismic Monitoring at Vaal Reefs Based on 1993 Knowledge

3.6 Summary and Conclusions

References

Chapter 4 No. 5 Shaft Experiment with Seismic Warning

4.1 Ass

umptions Behind the Seismic Warning Concept

4.2 The First Seismic Warnings (October-December 1994)

4.3 Procedure to be Followed After Issuing a Seismic Warning (January 1995)

4.4 Results of the 5B Experiment Using the Apparent Stress Concept (December 1994-May 1996)

4.5 Case Studies

4.5.1 Changes in Pattern of Seismicity as a Result of Changes in Mining Sequences

4.5.2 Change of Mining Sequence in the 5B Area Due to Seismic Information (September 1995)

4.5.3 Seismic Warning Dated 11-05-1995 (Polygon Outside of the Experiment Area)

4.5.4 Seismic Warnings for Areas with Limited Seismic Cover or Based on Uncertain Data

4.5.5 Correlation Between Seismicity and Mining Activity for Case Where Instability was Detected in Advance of Decrease in Mining Activity

4.6 Instability, Time, Polygon, and Size of the Event - Some Observations

4.7 Blast Time and Mining Strategy Changes for Workin

g Places Located Along the Same Geological Discontinues

4.8 Analysis of the Apparent Stress Concept Application Done by a Rock Engineer on Request of the Production Manager No.5 Shaft in January 1996

4.9 Analysis of Seismicity at No.5 Shaft for the Period February 1995 to July 1995

4.10 Limitations of the Method

4.11 Conclusions Resulting from the 5B Experiment

4.12 Summary and Conclusions

References

Appendix 4.1

Appendix 4.2

Chapter 5 Status of the Networks in the Klerksdorp Area by June 1997

5.1 Performance of the Networks

5.2 Network Management

5.3 Technical Description of the Networks Central Site

References

Appendix 5.1

Chapter 6 What Happened After 1997?

6.1 Predictions, Alert, Alarm, Scram, and the Seismic Warning

6.2 Applied Mine Seismology: A Vaal Reefs Perspective up to 1997

6.2.1 The Influence of the Mine Health and Safety Act and the Code of Practice

6.3 Rock Burst Control Strategies

6.3.1 Year Seismic Monitoring Strategy

6.3.2 Short Term Plan 1994 to 1995

6.3.3 Long Term Plan 1996 to 1998

6.3.4 Present Rock Burst and Damage Control Strategy

6.4 Code of Practice Research and Development Considerations

6.5 Seismic Workshop and Some Memos Dates 1996-1997

6.5.1 Seismic Workshop - November 1996 Recommendations

6.5.2 March 1997 - Memo "Legal Questions on Rock Engineering" 

6.5.3 End of March 1997 - Memo "Verification of the Vaal Reefs Method of Stability Analysis"

6.5.4 August 1997 - Memo "Rock Engineering Strategies Related to the Relevant Code of Practice" 

6.5.5 October 1998 - Memo "Panel Ratings, Follow-Up Procedure and Seismic Warning"

6.6 "A Guide to Routine Seismic Monitoring in Mines" (1998)

6.7 Summary

and Conclusions

References

Appendix 6.1

Index

O autorze

Stefan N. Glazer has over 40 years of experience in the application of geophysical methods in the mineral prospecting and mining industry. He has been an independent mine seismology consultant since 2004, and before that he worked as a mine seismologist for AngloGold and then PMC. He has an MSc degree in Prospecting Geophysics (1972) and a PhD degree in Mine Geophysics (1997), both from the AGH University of Science and Technology, Krakow, Poland. Prof. A. Kijko promoted the PhD thesis entitled “Practical applications of stress index and other seismological parameters in combating rock burst hazard in deep gold mine of Vaal Reefs, South Africa,” while Prof. S. Gibowicz and Prof. S. Lasocki reviewed it. He has published a number of technical papers, the last eleven of which are on monitoring the PMC caving process. He was involved in the Mass Mining Technology 2 Project with his research work entitled titled “Seismic signature of the caving process,” which involved analysis and interpretation of seismicity recorded at El Teniente, Chile, PT Freeport DOZ Mine, Northparkes Mine Lift 2 and PMC. The aim of this research was to make maximum use of the recorded seismicity to monitor and manage the caving process. In 2007 and 2011 he lectured on the subject of Mining Induced Seismicity for the Master Program in Geomechanics Applied to Mining, School of Engineering, Universidad de Los Andes, Santiago, Chile. In May 2016, Springer published his first book entitled "Mine Seismology: Data Analysis and Interpretation." This book describes the caving process as it was revealed by induced seismicity.

Blurb

This book illustrates how mine seismology can be used to improve underground safety standards. It describes several preventive actions that have been put into practice at the 5B Area of No. 5 Shaft Vaal Reefs gold mine after issuing seismic warnings. These included additional safety pillars, changes in mining sequences and directions, and a review of the mining strategy for the entire 5B area. 

The presented experiment with seismic warning concept was a success because it was an internal mine project. Further, the Vaal Reefs management adopted the philosophy that the success rate should be measured in the preventive actions taken, not in the success of the prediction itself. Reviewing these and other aspects, the book clearly demonstrates how mine seismology can effectively improve underground safety standards.

Stefan Glazer’s book (…) addresses in a very comprehensive manner both technical and practical proble

ms of implementing and then effectively using microseismic networks and data. (…) Stefan proves that through comprehensive microseismic data analysis the location of potential rock burst can be assessed and then prevention action plans can be developed, providing more confidence to management and workers that deposit[s] can be mine[d] safely. 
Michal Stawski, VP Strategic Geomechanical Specialist, PT Freeport Indonesia

I began reading this story expecting to find a technical review of the science of seismology and its application in mining, [but] this book is much more than that. (…) This is a must-read for those managing seismically active mines and should provide a wake-up call to the industry as the complex morality surrounding the management of seismic risk needs to be clarified in order for this to advance.
Eric Strom, Director Underground Mining, New Gold Inc.

As a mining geotechnical practitioner having experience

in large open pit and underground massive mining operations, I have learned that mining induced seismicity can have a significant impact on the safety and economics of operations. However, seismicity is a complex field that is generally left to specialists with little input from geotechnical engineers and engineering geologists. (…) This is a must read for mine seismologists, geotechnical practitioners and mining engineers alike, and will be a welcome and much needed addition to my own book cabinet. This will be [an] invaluable work as our industry progresses to the mining of new depths in both the underground and open pit environments.
Desmond Mossop Pr.Sci.Nat., Principal Engineering Geologist, SRK Consulting