28th Mine Seismology Seminar

Transcription

1 28th Mine Seismology Seminar May 2018, Thaba Eco Hotel Johannesburg, South Africa Sunday 13 May 09h30-17h00 Meeting of the International Research Advisory Board of the Institute of Mine Seismology Sunday 13 May 09h00-16h00 Course: Seismology Primer Sunday 13 May 18h00 Ice-Breaker hosted by the Institute of Mine Seismology Monday 14 May 08h45-18h30 Presentations on Seismic Monitoring and Seismic Hazard Management Monday 14 May 19h00 Dinner hosted by the Institute of Mine Seismology Tuesday 15 May 08h45-17h30 Presentations on Modelling & Monitoring the Seismic Rock Mass Response to Mining. Lectures on Ground Motion Hazard Training Courses, Thaba Eco Hotel 13 May, 09h00-16h00 Seismology Primer, Jacques Gerber/Olaf Goldbach 15 May, 14h00-17h30 Ground Motion Hazard, Dr Aleksander Mendecki & Dr Ernest Lötter 16 May, 09h00-16h00 Deformation-based Rockburst Support Design, Prof. Peter Kaiser 17 May, 09h00-13h00 Modelling with Seismic Data, Dr Dmitriy Malovichko/Jacques Gerber 17 May, 14h15-18h00 Ticker3D, Dr Ernest Lötter/Shane Kohler 18 May, 09h00-13h00 Vantage & Trace, Dr Ernest Lötter/Jacques Gerber/Talita Bacon For more information on registration, accommodation and social programme please contact

2 Objectives of the Seminar Considerable progress has been made in the quantification of seismic sources and in the quantification of seismicity. Most modern seismic systems are capable to locate seismic events with ray tracing and to quantify seismic sources by their seismic potency, moment and their tensors, radiated seismic energy and other derivatives. Seismicity is routinely characterised by its size and time distributions, including spatial and temporal clustering and migration, and by parameters reflecting changes in the strain and stress regime and the rheological properties of the rock mass deformation associated with the seismic radiation. Although seismic waveforms do not provide direct information about the absolute stresses and strains, they do provide useful information about stress orientation and about the spatial and temporal strain and stress changes. However, all these seismological parameters and seismic patterns are not always translated into a practical instruments to manage seismic hazard in mine. We will discuss methodologies to assess the long, intermediate and short term seismic hazard. It will include data selection, the issue of the maximum magnitude event, the power law size distribution and its intricacies, the GMPE - Ground Motion Prediction Equation, distribution of distances and mapping the ground motion hazard in space. We will also discuss the short term hazard in the context of re-entry protocol. Most applications of modelling with seismic data to date were limited to qualitative correlation between location and mechanisms of events with the modelled stresses. We will report encouraging results on the quantitative correlation that makes it possible to improve numerical modelling. We will also discuss methodology of modelling the influence of hydraulic fracturing on stress redistribution. Over the last few years we ve made considerable progress in the quantification of rock mass properties and monitoring their changes in space and time. Recent advances in active seismic monitoring, seismic interferometry and ambient noise analysis achieve a resolution at least 100 times better than classical seismic velocity inversion. This is useful to monitor the real-time stress changes in 3D due to mining, as well as quantification of pillar strength and more accurate cave front tracking in block cave mines. These advances have also enabled us to directly image and monitor areas affected by mining activities where classical seismology has not been very effective, such as tailings dams, old mine workings and natural caves. Finally, we will initiate discussion on what constitutes a Seismic Hazard Management Plan and also talk about the legal and ethical responsibility of mine seismologists and geotechnical engineers. The main themes of the Seminar are: - Progress in Passive Seismic Monitoring - Seismic Hazard: Quantification and Monitoring - Integration of Numerical Modelling with Seismic Data - In-Mine Seismic: In-mine Exploration and Rock Mass Characterisation - Seismic Hazard Management Plan - Legal and Ethical Consideration of Experts Involved I m asking all presenters to tell us: (1) why you did this work, (2) how you did it, (3) what you found, (4) what you think it means, and (5) what are the limitations. Looking forward to see you in South Africa in May 2018 Aleksander J. Mendecki Chairman and Head of Research Institute of Mine Seismology

3 28th Mine Seismology Seminar Day 1 Monday 14 May, 08h45-18h00, Thaba Eco Hotel, Lobola Hall, Johannesburg 08h45 Welcome and Introduction Dr Aleksander Mendecki, Chairman, Institute of Mine Seismology 09h00 Proactive Support Maintenance for Burst-prone Mines Dr Peter K Kaiser, Professor Emeritus, Laurentian University, Canada 09h30 Risk Based Dynamic Support Design Criteria William Joughin, SRK Consulting, South Africa 10h00 Operations Management in High Risk Mines Dr David Beck, Beck Engineering, Australia - Tea Break - 11h00 Modelling the Dynamic Response of a Tailings Dam to Mining Induced and Regional Seismicity Dr Lindsay Linzer, SRK Consulting, South Africa 11h30 Modelling the Effect of Hydrofracturing on Stress Redistribution in Hard Rock: Principles Dr Vladimir Lyakhovsky, Geological Survey of Israel 12h00 Modelling the Effect of Hydrofracturing on Stress Redistribution in Hard Rock: Applications Gys Basson and Dr Assen Ilchev, Institute of Mine Seismology 12h30 Using Seismic Interferometry to Image and Monitor Mining Environments Dr Gerrit Olivier, Institute of Mine Seismology - Lunch - 14h00 Monitoring at PT Freeport Indonesia, From the Depths of Space to the Depths of Papua: Integration of Disparate Data to Create a Holistic View of Changing Conditions Matthew Sullivan, Manager UG Geotechnical Monitoring, PT Freeport Indonesia 14h30 Reconstruction of Source Mechanisms of Large Complex Seismic Events Dr Dmitriy Malovichko, Institute of Mine Seismology 15h00 Drilling Into Seismogenic Zones of M2.0 - M5.5 Earthquakes From Deep South African Gold Mines: Preliminary Results From Cooke 4# and Moab Khotsong Mines Prof. Hiroshi Ogasawara, Ritsumeikan University, Japan and Prof. Ray Durrheim, University of the Witwatersrand, South Africa 15h30 Source Parameters of Seismic Events in Underground Mines from Regional Data and In-mine Seismic Systems: Examples from Swedish and Polish mines Prof. Savka Dineva, Luleå University of Technology, Sweden - Tea Break -

4 16h30 The High Frequency Shape of Source Spectra at Impala Platinum Mine Dr Steve Spottiswoode, Seismology Consultant, South Africa 17h00 The Use of Reflections From Passive Seismic Event Sources to Image Geological Discontinuities and Guide Underground Exploration Drilling Dr Richard Lynch, Institute of Mine Seismology 17h30 Measuring Seismic Velocity Changes Using Active Source and Noise Correlation Techniques Mark Green, Institute of Mine Seismology 18h00 Legal Responsibility, Risk, and Exposure Considerations for Mine Seismologists Dr Richard Brummer, President of Itasca Consulting Canada 19h00 Dinner hosted by the Institute of Mine Seismology 28th Mine Seismology Seminar Day 2 Tuesday 15 May, 08h30-17h30, Thaba Eco Hotel, Lobola Hall, Johannesburg 08h30 Velocity Amplification of Seismic Wave Across Fractured Zone and its Potential Application in Rock Support Design, Dr Ping Zhang, Luleå University of Technology, Sweden 09h00 A Fast Marching Method to Determine Seam-parallel Stress in the Fracture Zone of Tabular Mine Excavations Dr. John Napier, Univerity of Pretoria, South Africa 09h30 A Potency-Based DD-BEM Model for Seismic Failure: Applications to Tabular Mining Jacques Gerber, Institute of Mine Seismology 10h00 Integrated Studies of Rock Physics, Reflection Seismology and Induced Earthquakes in Deep South African Mines Dr Musa Manzi and Prof. Ray Durrheim, University of the Witwatersrand, South Africa - Tea Break - 11h00 Seismic Source Mechanisms of Production Blasts in a Narrow-vein Mine: Interpretation of Non-explosive Component Dr Dmitriy Malovichko & Denver Birch, Institute of Mine Seismology 11h25 Best Practice for Microseismic Monitoring of Caving Mines Dr Richard Lynch, Institute of Mine Seismology 11h50 A High-Resolution Model for Pillar Stability in Multi-Seam Coal Mines Jacques Gerber, Institute of Mine Seismology 12h15 Short Term Activity Tracking for Coal Pillar Stability Cornel du Toit, Institute of Mine Seismology 12h40 Wide-area Mine Seismicity Monitoring Using Fibre Optic Distributed Acoustic Sensing (DAS) Daniel Finfer, Silixa, UK - Lunch -

5 28th Mine Seismology Seminar Day 2 Short Course on Ground Motion Hazard Principles and Applications Tuesday 15 May, 14h00-17h30, Thaba Eco Hotel, Lobola Hall Course Instructors: Dr Aleksander J. Mendecki & Dr Ernest Lötter, Institute of Mine Seismology 1. Seismic Hazard Definitions and Objectives 1.1 Size distribution hazard. 1.2 Ground motion hazard. 1.3 Modelling ground motion deterministic hazard. 2. Ground Motion Characteristics 2.1 Ground motion at source: limits and scaling. 2.2 Factors influencing the observed ground motion in mines. 2.2 Peak ground velocity (P GV ), acceleration (P GA) and displacement (P GD). 2.3 Cumulative Absolute Velocity (CAV ) and Cumulative Absolute Displacement (CAD). 3. Ground Motion Prediction Equations (GMPE) GMPE gives the expected value of a given ground motion parameter, e.g. P GV or CAD as a function of magnitude and distance. 3.1 What it is and what it isn t the utility of GMPE. 3.2 Selection of data, the near-source saturation, constraints. 3.3 GMPE for P GV and its applications. 3.4 GMPE for CAD and its applications. 3.3 Monitoring the consumption of the deformation capacity of the support due to seismicity. 4. Mapping Ground Motion Hazard (GMH) GMH gives the probability that a given level of ground motion can be exceeded at any point of interest, X, in future time T, Pr [ v (X), T ]. The particular points of interest may be major underground or surface infrastructure: shafts, pump stations, crushers, water pillars or major access tunnels. In addition, having computed these probabilities at a number of points they may be presented as maps, i.e. contours or iso-surfaces. GMH incorporates the size distribution analysis, the ground motion prediction equation (GMPE) and the distribution of distances from the relevant seismic events to a given site. We will present examples of applications with movies. 5. Exclusion Zones and Exclusion Times 5.1 System based on seismic activity Why not Omori and why non-parametric System based on space-time triggering and P GV s. 5.3 Traffic light system for re-entry 5.4 Real-time monitoring for re-entry with examples with movies. 6. Site Effects 6.1 Strain bursting and secondary sources. 6.2 Ground motion amplification at the skin of and close to excavations. The course is based on Mine Seismology Reference Book: Seismic Hazard by A. J. Mendecki, Institute of Mine Seismology, free download at

6 28th Mine Seismology Seminar Day 3 Course on Deformation-based Rockburst Support Design Wednesday 16 May, 09h00-16h00, Thaba Eco Hotel, Conference Kraal Course Instructor: Prof. Peter K. Kaiser. Dr. Peter K Kaiser, Professor Emeritus, joined Laurentian University in 1987 as Professor of Mining Engineering and Chair for Rock Engineering and Ground Control at the Bharti School of Engineering. He was the founding President of MIRARCO and later was seconded to the Centre for Excellence in Mining Innovation (CEMI) as Founding Director and then as Director of the Rio Tinto Centre for Underground Mine Construction. He is a specialist in applied research for underground mining and construction and brings extensive experience from both the industrial and academic sectors having served as consultant to numerous consulting engineers, mines, and public agencies. Dr. Kaiser is a Fellow of the Engineering Institute of Canada (EIC) and the Canadian Academy of Engineers and in 2013 was awarded the Julian C. Smith Medal of the EIC for "Achievement in the Development of Canada". He is the author of more than 300 technical and scientific geomechanics publications. In 2016, he has delivered the Muir Wood lecturer at the WTC and the MTS lecture at the 50th US Rock Mechanics Symposium. Brief Description As mining and civil tunneling progresses to deeper grounds, mining-induced stresses cause rock mass failure of hard rock with static and dynamic impact on ground support. Both can lead to large bulking deformations that are imposed in a static or dynamic manner on the rock support. The course instructors have revised and significantly updated the Canadian Rockburst Support Handbook (1996) with a much greater stronger focus on strain-burst assessment and related damage mitigation. This revision will be released in early 2017 as a Guide for Rockburst Support Selection and will form the background for this one-day course. During this workshop, brittle rock mass failure processes will be reviewed within a frame work of support selection for highly stressed ground. Static and dynamic failure processes will be discussed and illustrated on case examples. Deficiencies in current approaches will be discussed with the intent of pointing the way to more rational support design methods for conditions experiencing mining-induced stress change. This workshop is intended to stimulate discussion on the above-described engineering challenges. The presentations will cover limitations of standard support design by classification, aspects of deformation-based support design, limitations of ground-motion-based burst-support design, engineering challenges of strain-bursting ground, methods to control and mitigate seismic risk by use of support to mitigate damage. Reference material will be distributed to the registrants in electronic format. Specifically, Drs Kaiser will cover the following topics. (1) Elements of excavation design. (2) Geotechnical design process and quantification of variable design inputs. (3) Anticipating rock mass behaviour at depth. (4) Brittle failing ground and impact of rock mass variability. (5) Depth of failure in stress-fractured ground. (6) Bulking of stress-fractured rock. (7) Deformation-based support design. (8) Safety margins for support design and limitations of standard approaches. (9) Gabion support concept for stress-fractured ground. (10) Deformation-based support selection. (11) Unstable rock failure processes. (12) Mechanism of unstable rock failure in laboratory and in-situ. (13) Numerical simulation of unstable rock failure. (14) Strain-burst assessment and strainburst damage mitigation. (15) Seismically triggered and mining-induced strain-burst. (16) Dynamic support design principles for strain-bursts. (17) Identification of burst prone areas. (18) Energy demand estimation. (19) Support selection. Some reference material will be distributed to the registrants in electronic format.

7 28th Mine Seismology Seminar Day 4 Short Course on Stress Modelling with Seismic Data Thursday 17 May, 09h00-13h00, Thaba Eco Hotel, Conference Kraal Course Instructors: Dr Dmitriy Malovichko, Institute of Mine Seismology Jacques Gerber, Institute of Mine Seismology 1. Quality and consistency of seismic data 1.1 Location of sources: uncertainty of location, outliers. 1.2 Source parameters: bandwidth limitations, local site effects. 1.3 Source mechanisms: orientation settings, manual and automatic moment tensor inversion. 1.4 Classification of sources: normal events, blasts, ore pass noises. 2. Stress modelling and post-processing tools in Vantage 2.1 Solving models using IMS boundary element code (ISSM). 2.2 Importing the 3rd party stress data (Map3D, Flac3D). 2.3 Calculation of principal stresses and modelling parameters. 2.4 Visualisation of results: vectors, meshes and data points, charts. 3. Validation and improvement of numerical stress models using seismic data 3.1 Seismicity stress model: location and size of events vs spatial distribution and magnitudes of stresses, source mechanisms vs direction of principal stresses, stress inversion from source mechanisms. 3.2 Stress model seismicity: simulation of seismicity using the Salamon-Linkov method, comparing modelled and observed seismicity (location, sizes and mechanisms of events). 4. Assessment of seismic hazard in space (Seismic Hazard Map) 4.1 Forecast of seismic hazard associated with future mining. 4.2 Testing the forecasts. Presentation and the relevant publications will be available in electronic format. 28th Mine Seismology Seminar Day 4 Short Course on Real-Time Monitoring of Seismicity with Ticker3D Thursday 17 May, 14h15-17h00, Thaba Eco Hotel, Conference Kraal Course Instructors: Dr Ernest Lötter, Institute of Mine Seismology 1. Ticker3D 1.1 Initial Configuration. 1.2 System Health and Management Viewing health of system components Sensitivity Analysis. 1.3 Recent seismicity. 1.4 Long term seismicity Event Filters Time History, Size Distribution and other plots Spatial contours of seismicity Spatial clustering. 1.5 Production Data Management. 1.6 Basic Reports. Attendees with modern laptops will receive a license for Vantage with which to perform hands-on tasks during training and gain experience. Presentation used during the

8 course and the relevant publications will be available in PDF format. Note that in order to run Vantage, we strongly recommend a machine with at least 4GB of RAM and a modern 3D graphics card (NVidia or AMD) with up to date drivers installed. 28th Mine Seismology Seminar Day 5 Short Course on Seismological Processing with IMS-Trace and Visualisation with Vantage Friday 18 May, 09h00-13h00, Thaba Eco Hotel, Conference Kraal Dr Ernest Lötter, Institute of Mine Seismology 1. Location Primer 1.1 P- and S-wave arrival picks. 1.2 Polarisation analysis. 1.3 Locating seismic events: absolute, relative or with ray tracing. 1.4 Marking events as accepted, rejected or blasts. 1.5 Travel time processing. 2. Source Parameter Primer 2.1 Basic source parameters: seismic energy, seismic potency and moment, magnitude. 2.2 Derivative source parameters: apparent stress, energy index, apparent volume. 2.3 Source spectra. 2.4 How to improve source parameter estimates. 2.5 Mechanisms of seismic events Decomposition plots Hudson diagram. 2.6 Dealing with noisy data. 3. Velocity Structure 3.1 Velocity calibration. 3.2 Wadati diagrams. 3.3 How to build a 3D velocity model. 4. Alternative Ways to Browse Seismic Data 4.1 Exporting information from the database. 4.2 Parameter filters. 4.3 Automatic queries. 4.4 Exporting seismograms. 5. Vantage Visualisation 5.1 Interacting with the 3D viewer. 5.2 Loading and customising mine plans. 5.3 Loading seismic data from IMS Database Server. 5.4 Colouring and sizing of events. 5.5 Parameter, temporal and spatial filtering of the data. 5.6 Displaying source mechanisms. 6. Vantage Analysis 6.1 Analysis in temporal, spatial and parameter domains Time histories Contours (event parameter gridding onto meshes) Energy-potency or energy-moment plots Rank statistics of ground motions. 6.2 Event size distribution: open-ended and upper-truncated models, maximum size of event, probability table 6.3 Source mechanisms: stereo-net of principals axes, nodal planes and poles, Hudson s source type plot, Frohlich s ternary graph. Attendees that will bring a modern laptop will receive a license for IMS-Trace with which to perform hands-on tasks during training and gain experience. Presentation used during the course and the relevant publications will be available in pdf format.

9 28th Mine Seismology Seminar Sunday, 13 May 2018 Pre-Seminar Course Seismology Primer Sunday 13 May, 09h00-16h00, Thaba Eco Hotel, Conference Kraal Course Instructors: Jacques Gerber, Institute of Mine Seismology Olaf Goldbach, Institute of Mine Seismology Course Objectives. The objective of the course is to explain basic seismological concepts of seismic waves and sources to non-seismologists to facilitate better understanding of lectures, presentations and training courses offered during the Seminar. Course Programme. 1. Objectives of seismic monitoring: rescue, prevention, hazard assessment, alerts and back analysis. 2. What is a seismic event, types of seismic waves, sources of seismic waves, acceleration, velocity and displacement of ground motion (particle velocity) vs. wave speed (propagation velocity). 3. Event locations and location errors, design principles of seismic network configuration, velocity calibration, calibration blasts and Wadati diagram. 4. Direct source parameters: origin time and location, Fourier transformation, frequency decomposition, spectra and spectral parameters, seismic potency, seismic moment, radiated energy, corner frequency and size. 5. Derived source parameters: static and dynamic stress drop, apparent stress, apparent volume, energy index. 6. Magnitude scales: local, moment or potency magnitudes, energy magnitudes. 7. Types of faults, radiation patterns and fault plane solutions, stress orientation. 8. Size distribution (Gutenberg-Richter relation), seismic hazard and risk, probabilities and hazard maps. 9. Clustering, time histories of seismic parameters, histograms, cumulative plots. Presentation and the relevant publications will be available in electronic format.