Level 3 Training – Normal User

 

Welcome to Level 3 of the mXrap software training programme. You should be familiar with the most aspects General Analysis from Level 2 training. We’ll just look at the last couple of functions in General Analysis, then move on to learn the other most popular applications.

 

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Event Comments

 

There are many reasons you might want to store a short snippet of text associated with an event. There are two ways to do this in mXrap; event tags and event comments. Event comments can be unique and about anything, they have no effect on filters.

 

 

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Event Tags

 

Event tags can be used to group events into categories. Example tags might be “suspected blast”, “damage occurred”, “suspect location”, “outlier” or “likely crusher noise”. These tags can be used in event filters to quickly show or hide particular categories.

 

 

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Distance Charts

 

You’ve already seen how to filter by distance to survey, these chart let you plot seismicity as a function of distance. They can be handy to see which fault has the most seismicity associated. Of course, sometimes a structure will have a lot of seismicity nearby because you happen to do a lot of blasting nearby. You can also plot blasts as a function of distance to survey.

 

 

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Config Clipping Volumes

 

You’ve already been using clipping volumes, here is how to modify or add new clipping volumes.

 

 

 

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Config Filter Volumes

 

Configuring clipping volumes is similar to adding a new filter volume. The main difference is you can also add more complicated selection boxes as a filter volume. This video runs through that process.

 

 

Exercises

  1. Find a significant event in the database
    1. Add a comment on why it was significant, did it cause damage? was it felt on surface? etc.
  2. Make a selection in the logE-logM chart where there are high EI and high moment
    1. The make selection/s in the diurnal chart for events during your normal blast times
    2. AND all the selections together
    3. Tag them as “Potential Blast”
    4. Add the meaning of the new tag as “Outlier”
  3. Turn on three of your faults in the Distance to Surveys list
    1. Open the Seismicity vs Distance to Survey chart for individual surveys
    2. Increase the max distance to 400
    3. Which fault looks like is has the most seismicity nearby?
    4. Does this change when looking at energy, moment or displacement?
    5. Show the surveys list as a legend

 

 

Seismic Event Quality

 

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Event Quality

 

The seismic event quality app provides tools to evaluate the quality of the database and highlight potential bad quality data. Noise, blasts and bad quality data can be tagged and excluded from analysis in other apps. The event quality app includes potential blast detection, spatial filters and outlier detection.

 

 

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Quality Settings

 

This video shows where the event quality settings are and how to modify them.

 

 

 

The following papers explain various aspects of the Seismic Event Quality application.

Morkel, IG & Wesseloo, J 2017, ‘A technique to determine systematic shifts in microseismic databases’, in, Proceedings of the Eighth International Conference on Deep and High Stress Mining, 2017, Australian Centre for Geomechanics. https://papers.acg.uwa.edu.au/p/1704_17_Morkel/

Morkel, IG & Wesseloo, J 2017, ‘The effect of sensor frequency range on the estimation of the current hazard state’, in J.A. Vallejos (ed.), 9th International Symposium on Rockbursts and Seismicity in Mines, 15-17 November 2017 2017, Santiago, Chile.

Morkel, IG, Wesseloo, J & Harris, PC 2015, ‘Highlighting and quantifying seismic data quality concerns’, in PM Dight (ed.), Ninth International Symposium on Field Measurements in Geomechanics, 9-11 September 2015, Sydney, New South Wales, Australia, Australian Centre for Geomechanics, pp. 215-222.

 

Exercises

  1. Check for data quality concerns in:
    1. Event density plots
    2. Shifts in source parameters
  2. Open the Event Quality Settings window
    1. Review the location quality bounding box, is it appropriate? Missing important events?
    2. What number are you using for the min number of sensors for a quality events?
  3. Open the Potential Blast Viewer window
    1. Set the parameters to list some potential blasts in the potential blasts table
    2. Review the waveforms of some of the potential blasts and review the processing

 

 

Omori Analysis Tools

The Omori Analysis app provides several windows each dedicated to specific tasks. The window provides the ability to select a blast or blasts from the blast database for which the “Omori chart” is provided for the events within a specified volume around the blast(s) and a specified time after the blast(s). If more than one blasts is selected the individual and the stacked cumulative event distribution is provided.

Another window is dedicated to performing a best-fit of the Modified Omori Law to the events associated with a selected blast. The chosen volume and time window and the parameters for the MOL is saved. Another window dedicated to the analysis of these results is provided. The statistical and spatial distributions of the MOL parameters are assessed based on the saved parameters from the MOL best-fit.

The spatial and statistical distributions of the MOL parameters provide input to the re-entry analysis which is provided in another window. The re-entry assessment is based on the work by Vallejos and McKinnon (2010) and can be used in real time assessment of re-entry or for the back analysis of historical data to develop re-entry protocols.

 

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Blast Editor

 

You will need blast data to use this app. This video shows you how to manage your blast information.

 

 

 

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Response to Blasting

 

The response to blasting window lets you quickly plot the seismic response over time and space for selected blasts.

 

 

If you are wondering why there is no cumulative energy line, read this blog post for an explanation.

 

 

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MOL Analysis

 

The MOL analysis window lets you fit responses to blasting with the Modified Omori Law.

 

 

 

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MOL Results

 

The MOL results window shows the distribution of MOL parameters for fitted blast responses. 

 

 

 

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Re-entry Analysis

 

The re-entry analysis window utilises the methods described by Vallejos and McKinnon (2010) to compare the selected responses with the database of modelled responses. This can be used to identify abnormal responses.

 

 

This app is largely based on the PhD by Javier Vallejos. The PhD can be downloaded here. The paper below is a summary of the re-entry methodology. There are two more papers below about the implementation and effectiveness of the method.

Vallejos, J.A. and McKinnon, S.D. (2010) Temporal evolution of aftershock sequences for re-entry protocol development in seismically active mines. In: Van Sint, J.M. and Potvin, Y. (eds). 5th International Seminar on Deep and High Stress Mining, 2010 Santiago, Chile. Australian Centre for Geomechanics, pp. 199-214.

Morkel, IG & Rossi-Rivera, P 2017, ‘The implementation and quantification of the Vallejos and McKinnon re-entry methodology’, in, Proceedings of the Eighth International Conference on Deep and High Stress Mining, 2017, Australian Centre for Geomechanics. https://papers.acg.uwa.edu.au/p/1704_58_Morkel/

Tierney, S & Morkel, IG 2017, ‘The optimisation and comparison of re-entry assessment methodologies for use in seismically active mines’, in, Proceedings of the Eighth International Conference on Deep and High Stress Mining, 2017, Australian Centre for Geomechanics. https://papers.acg.uwa.edu.au/p/1704_59_Tierney/

 

Exercises

  1. Open the blast editor
    1. Is the blast database up-to-date? If not, update it!
    2. If it is, try adding a pretend blast and deleting it again.
  2. Open the Response to Blasting window
    1. Plot blasts in 3D and colour by the number of events, is there a pattern?
    2. Plot the Omori charts for the five blasts with the highest event counts.
    3. Note the difference between the normalised, stacked and individual charts
    4. Go through the top five blasts one-by-one and adjust the spheroid and time filters to capture the main response events
      1. Is there a pattern in the typical spatial distribution of events?
  3. Open the MOL Analysis window
    1. How many blasts have MOL parameters assigned (p, K, c)?
    2. Find a blast with more than 20 events that hasn’t been modelled yet and fit the MOL
    3. Try to do at least 5 fits
  4. Open the MOL Results window
    1. Plot the all blasts with a modelled MOL in 3D
    2. Colour by p-value, is there a pattern in space?
    3. Colour by K-value, is there a pattern in space? Does it seem higher where you have good system sensitivity?
    4. Tick just your three most recent blasts with a modelled MOL, where do they sit on the overall distributions of p and K? About average? Towards the top? Towards the bottom?
  5. Open the Re-entry Analysis window
    1. Tick a recent blast
    2. When did it start to move horizontally through the percentile curves?
    3. When did it drop below the Tmc line?
    4. When did it drop below the Background line?

 

 

Grid Based Analysis

The grid-based analysis app provides the tools to evaluate the spatial distribution of seismic source parameters. Based on specified input parameters, a 3-Dimentional spatial kernel interpolation is performed to assess the mean value of seismic source parameters on a given grid. Cumulative source parameters like cumulative apparent volume are assessed through a variable bandwidth kernel interpolation of which the bandwidth is a function of the source size. The b-value is evaluated by implementing a robust algorithm for finding the magnitude of completeness and b-value pair for each grid point.

Post-processing includes the three-dimensional display of results using colour, transparency and gridpoint scaling. Filtering of gridpoints and the events contained in the volumes represented by the gridpoints can be performed. This grid based event filter can also be used for general analysis.

 

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Setup Grid Based Analysis

 

This video guides you through the initial setup process for the Grid-Based Analysis app, how to set the grid and check the data period and grid extents.

 

 

 

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Transparency Function

 

The transparency controls let you highlight different results. Maybe you want to highlight low stress areas or high stress areas.

 

 

 

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Grid Results

 

This video goes through how to display the grid results. There are many options available to either plot the grid as points or isosurfaces.

 

 

 

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Config Grid Volumes

 

This video explains how to modify or add a new grid.

 

 

 

Many aspects of this app are discussed in the two papers below.

Wesseloo, J., Woodward, K.R. and Pereira, J. (2014) Grid-based analysis of seismic data. J. S. Afr. Inst. Min. Metall. October 2014.

Wesseloo, J. (2014) Evaluation of the spatial variation of the b-value. J. S. Afr. Inst. Min. Metall. October 2014.

 

Exercises

  1. Plot the b-value grid points based on the whole data base (Use a 10m grid)
    1. What areas have the lowest / highest b-values?
    2. Investigate this by plotting the grid points in the following ways
      1. All points with the same transparency (say 50%, play with the number)
      2. Fade out the high values (play with translation and scaling)
      3. Fade out the low values (play with translation and scaling
      4. Fade out the centre portion of values (play with translation and scaling)
  2. Plot the EI based on the whole data base (Use a 10m grid)
    1. What areas has the lowest / highest EI
    2. Investigate this by plotting the grid points in the following ways
      1. All points with the same transparency (say 50%, play with the number)
      2. Fade out the high values (play with translation and scaling)
      3. Fade out the low values (play with translation and scaling
      4. Fade out the centre portion of values (play with translation and scaling)
  3. Plot the CumMo based on the whole data base (Use a 10m grid)
    1. What areas underwent the highest “co-seismic damage”
    2. Use dynamic clipping to view horizontal slices of the mine, from bottom-to-top
  4. Open Post Processing 3D and controls
    1. Filter to show the grid points with highest 50% of EI
    2. Copy the post-filtered events into the Base filter and plot the FM chart
    3. Do the same for the lowest 50% of EI, was there a change in b-value between the two sets of events?

 

 

Hazard Assessment

The grid-based seismic hazard assessment app assesses the current seismic hazard for the mine based on the recent seismic history. An assessment of a mine-wide value for Mmax is performed based in the work presented by Kijko and Singh (2011) and Lasocki and Urban (2011). The spatial distribution of b-value and event density for the recent history is performed and used as input to a probabilistic evaluation of the spatial distribution of the seismic hazard. The results of this probabilistic calculation is presented in space in several ways through iso surfaces and pseudo volumetric rendering.

The probabilistic distribution of the peak-particle velocity is calculated for minodes and seismic hazard map in terms of the probabilistic evaluation of the strong ground motion being produced. The minodes can be interrogated and the contribution of different sources evaluated.

Here are some blog posts that have discussed issues related to seismic hazard assessment:

Frequency-Magnitude Chart Anatomy

To a/b or not to a/b

What on Earth is M_UL?

Sensitivity to b-value

 

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Intro, MUL and Iso View

 

This video goes through the initial setup for the hazard assessment application, the estimation of MUL and the grid-based hazard calculations.

 

 

 

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Excavation View

 

The previous video showed the isosurface view that is independent of excavations. The excavation view shows the ground motion hazard on work areas. 

 

 

 

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As an extension to the excavation hazard, you can calculate the hazard for minodes within each of your filter volumes. This video shows you these tools as well as a function to track the hazard for filter volumes over time.

 

 

 

 

The paper below explains the calculation process used in the Hazard Assessment application.

Wesseloo, J 2018, ‘The Spatial Assessment of the Current Seismic Hazard State for Hard Rock Underground Mines’, Rock Mechanics and Rock Engineering.

 

Exercises

  1. What is the current MUL for your database?
    1. Set the backdate to just before your largest ever event, what was the MUL then?
    2. And before the previous largest event before that?
  2. Plot the Hazard Isos for the last 6 months of data, plot the ML rating for the whole mine
    1. Plot the b-value and Event Rate Iso’s too
    2. What corresponds to the hazard hotspots most, b-value or event rate?
    3. What did the ML rating look like just before your most recent large event?
  3. Plot the equiprobability zones on your development wireframes
    1. Now switch to minodes, again plot the equiprobability zones
    2. Plot the PPV-Probability curves
      1. Is there an even distribution of ground motion hazard between your lowest and highest hazard areas
      2. Do you have a lot of low hazard areas and then a small area of high hazard?
    3. Select a block of minodes in the deepest areas of the mine
    4. How does the overall probability and the probability curves compare between the selected minodes and all minodes
      1. Vary the design PPV, magnitude and distance values and note the changes
      2. What about just selecting one minode?
  4. What about just one small length of tunnel?
  5. Plot the 3D hazard contribution for a minode between two hazard hotspots
    1. Which hotspot contributes most to the hazard at that minode?

……Hint: scale markers by contribution

 

 

Plane Fitting

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Plane fitting

The plane fitting app provides a tool for fitting a plane through selected seismic events. The app performs Principal Component Analysis (PCA) on the spatial data provided and generates a plane normal to the minor axis with the extent determined by the major and intermediate axis.

A stereonet is provided showing the pole of the plane from the PCA. Planes are also fitted through three-event combinations of the selected events. The pole distribution of these planes is shown as contours on the stereo net. A goodness of fit analysis is performed and a simplified ranking assigned to the best-fit plane.

The plane can be exported as a *.pnt file for later re-use in a “distance to” filter or for display in other apps and programs.

 

Exercises

  1. Use the distance to survey filter to create a set of events around a planar fault (or find a planar set of events)
    1. Run the plane fitting calculation for the base filter events
    2. What is the quality of the fit?
    3. Does the plane orientation match the fault?
    4. Adjust the strike length and dip length to match the spread of events
    5. Export the plane as a dtm/str and build the cache to use in general analysis
    6. Show the plane volume and adjust the thickness to match the spread of events
    7. Add the plane volume as a volume specific filter

 

 

mXsync

 

mXsync is a piece of software installed separately to mXrap that facilitates the backup, restore and upgrading of the site root folder. We hope this new root folder management system will allow new and improved apps to flow more easily and more quickly to sites. 

 

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Intro and Default Backup

 

This video introduces the mXsync software, goes through the basics and how to perform a default backup of your root folder. It is a good idea to run a default backup at least once per month. This will allow you to restore files into your root if required (like a corrupted blast database).

 

 

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Apply a patch

 

A patch is a list of commands to modify the root folder by adding, removing or modifying files. You will occasionally be sent patches by ACG, maybe to add a new application or make other modifications. This video shows you how to apply patches you have been sent.

 

 

 

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Chat window

 

The chat window allows you to send messages, files and screenshots to the ACG or another third party that has access to your root folder.

 

 

 

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Edit default backup

 

The default backup does not usually include everything in your root. This video shows how you can edit what is included in the default backup.  

 

 

 

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Modify download permissions

 

Only a small number of people have access to your root folder through mXsync. Usually this is just the people at ACG but you might also want to allow other people access to your data. Maybe you have a sister site or people working in a corporate office. Here is how you can modify who has access to your root folder.

 

 

 

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Download a component

 

You can download components from the mXsync server onto your computer. These components might be another root folder of a root subcomponent. This video shows you how to download the Tasmania and Big Bell root folders. These mines have closed down and their data is publicly available.

 

 

 

 

If you are familiar with the content above and completed the exercises, congratulations! You have completed the Level 3 user training in mXrap. You now know the most commonly used aspects of mXrap. The next training level will go through the remainder of the apps relevant to your site.

Start Level 4