Dr. Kelln shares Seequent’s workflow solution for geotechnical engineers faced with the challenge of analysing tailings storage facilities that evolve over time.
In this session, learn the following:
- The challenges faced by geotechnical engineers dealing with evolving site conditions
- How a dynamically updated digital twin enables rapid re-interpretation of site conditions
- Discover the evaluation of design alternatives by enabling the geotechnical engineer to rapidly and easily create numerical models drawn from this ‘single source of truth’.
- How to uncover valuable insights from data vis-à-vis interpretation in context
Director, Geotechnical Analysis – Geostudio – Seequent
<v Host>Hello, and welcome to</v>
the second installment of our webinars series,
Sequence Dynamic Digital Twin Solution
for Modern Tailings Storage Facilities Management.
My name is Chris Kellen and I’m the Director of Engineering
for the GeoStudio business unit here at Seequent.
Today, I will guide you through the second portion
of our proposed workflow for managing
storage tailings facilities,
focusing on the interoperability between a 3D leapfrog
geological model and the geotechnical analysis
conducted in GeoStudio.
Our aim is to explore how geotechnical engineers,
responsible for the analysis, design, and management
of these facilities
can use a dynamically updated digital twin
to overcome challenges around evolving site conditions
and the interpretation of field data in context.
Please note that this presentation
is for informational purposes only,
and is not a commitment to deliver software features
The software products that will be shown in today’s webinar
are the latest versions of Leapfrog, Central, and GeoStudio.
Despite the webinar’s technical connotation,
the presentation is designed for a wide audience,
both from the technical and non-technical domain.
During the webinar,
the audience is muted to ensure that the presentation
does not run over time.
But should you have questions,
please don’t hesitate to write into the question window
in the Go To meeting.
We will make sure that a personalized reply
will be sent to you via email in due time.
After the webinar,
we would like to ask you to remain
for one to two minutes longer
to partake in a short survey that will help us understand
your needs and learn how we can improve our offerings.
And as always,
if you wish to maintain or share a recording
of this webinar, a link to the video
will be sent shortly after the presentation.
Okay, let’s get started.
It’s our mission here at Seequent
to enable customers to make better decisions
about the earth, environment, and energy challenges,
because it is the robust decision-making process
that provides security and longevity in your organization.
Now, arguably, one of the most important decisions
the global mining community recently made
was to commit to an improved due diligence process
regarding the safe and sustainable design,
construction, maintenance, and remediation
of tailing storage facility.
This commitment was formalized
in the global standard on tailings management.
The key thing for this webinar
revolves around transparency and design,
maintenance, and post closure of the dam.
Transparency is particularly important
for the geotechnical engineer
that is also the engineer of record,
because the rationale behind any decisions
must be documented and made clear to all stakeholders.
Transparency in the engineering analysis,
design, and operation of a TSF does not come easy.
A TSF is generally designed and operated
using the observational method,
which adopts a design based on realistic assessment
of natural ground conditions.
The design is not purposely conservative.
And in nearly all cases,
changes to the final facility design
are mandated by operational constraints.
Both the design and our understanding of the site
are constantly evolving.
As such, operators and the engineer of record
are responsible for detecting changes
in the current and future performance
of the facility and then acting to mitigate risk.
But discerning these changes is not trivial.
It requires targeted monitoring data
and a thorough conceptual model of the mechanisms
Interpretation of new observational data
to characterize the geotechnical processes
controlling performance is difficult.
The data must be readily accessible via dashboard
or some sort of system.
And more importantly,
the data must be interpreted in the context
of the physical system.
In the previous webinar,
Yanina talked about the key elements of the solution,
which included a single source of truth
and the digital twin.
Today, we’re going to draw our attention
to the digital twin and its role
in geotechnical engineering.
Seequent’s geological modeling
and visualization application, Leapfrog,
is designed to provide the core elements of a digital twin
for geotechnical engineers.
A Leapfrog model is constructed
from a wide variety of data sources,
including borehole, structural, GIS,
geophysical, historical cross sections,
other site data, and more.
Engineering designs from a CAD package
can be incorporated directly into the geological model
for rapid visualization of infrastructure,
such as the virtual earthworks, bridges,
dams, tunnels, and more.
For a geo-technical engineer,
a leapfrog could more aptly be called
a subsurface digital twin
because it can be used to model anything
below the ground surface,
including the geotechnical structure.
The challenge for the geotechnical engineer,
then, is ensuring that the geotechnical analysis
is consistent with the evolving site conditions.
In the Seequent ecosystem,
this is accomplished through seamless interoperability
between the geological model
and the geotechnical analysis in GeoStudio.
The sum of these parts form the complete digital twin
of the site.
I will now demonstrate using Leapfrog,
Central, and GeoStudio.
I will start the demonstration by briefly reviewing
the digital twin of the site created in Leapfrog.
First, we can bring in the topography of the site.
This can be point cloud data, mesh data,
and so on.
Then for this particular example,
I brought in the following borehole data.
And then using this borehole data,
we’re able to create a geological model
using a variety of tools.
In this case,
we use the stratigraphic surface chronology approach,
creating this sequence.
And so we can review our various contacts
generated from this borehole data.
And then with this contact data created,
we can then output a full geological model.
This is the geological model that I’m now going to use
to create a 3D finite element-ready geometry
for analysis in GeoStudio.
The first step is to publish the Leapfrog project
In this window, I select which objects from the model
to include in the publication.
Naturally, I can include the topography
and the entire geological model, GM.
Once this process is complete,
I can navigate down to the bottom left,
select the button, and launch the Central portal.
Here we are in Central,
where the tailing storage facility
Leapfrog project has been published.
The history is shown, along with a number of tabs
to review files, users, and again,
the history of the project.
In GeoStudio, BUILD3D,
I have already imported a background mesh
for the topography of the site.
I’ll turn off the visibility
and navigate to import background from Central.
In this window, I select the Central server,
then the project name, then the branch,
the ID, and finally, the geological model.
After hitting okay,
I will navigate into the import background window
and change some of the key settings
to create these background meshes.
First off, notice I can select which background mesh
from the geological model I want to include in import.
Further down, we have a transformation section
of the dialog box.
Notice once the import is complete,
that the background meshes are not oriented
with the surface topography.
From the dropdown,
I can select a saved transformation.
This automatically remaps the axes
from Leapfrog coordinates to GeoStudio coordinates
and moves the base points such that the background meshes
are located closer to the 0-0-0 axes.
BUILD3D is a parametric modeling package.
As such, the background meshes need to be converted
to spline surfaces using the fit to surface tool
The surface is selected from the geometry explorer window,
under the background meshes.
The visibility of the background meshes
can be toggled on and off in this view.
I will leave visible the surface representing the contact
between the bedrock and overlying clay unit.
With that done, the fit for surface icon is selected,
and three parameters are adjusted,
including the acceptable difference
between the background mesh and the spine surface,
the resolution, and a parameter controlling
the flexibility of the surface.
For this problem, I will adjust
both the resolution and the flexibility to 0.75.
Rotating the surface in space
reveals an acceptable fit
compared to the original Leapfrog surface mesh.
Next, I will turn off the visibility of the background mesh
and turn on the next stratigraphic layer,
repeating the process of using the fit to surface tool
on each occasion.
The process is repeated for each subsequent contact
along with the ground surface.
It is evident in the geometry explorer
that new surface bodies are added to the list
with each successive operation.
Now that the surfaces have been created,
I will unsuppress a sketch that I created
on the X-Z plane.
I will right click and edit this sketch
to demonstrate that I offset the plane for this sketch
in the y-direction, or vertical direction,
to ensure that it was located
beneath the lower stratigraphic surface in the domain.
The extrude icon is then selected
to push the profile upwards and generate a solid body.
I arbitrarily selected an extrusion distance of 150 meters
to ensure that the top of the block
far exceeds the ground surface elevation.
Clicking on the operation and the design history
reveals a single solid.
The cut tool is now used to turn the cube
into a geometry that is consistent with
the geological model in Leapfrog.
The cut operation that I select
removes the cutting tool,
which in this case are the surface bodies,
after the cutting operation is complete
Inspection of the resulting geometry
reveals a number of individual solids.
The delete body is used to remove
the upper most solid, leaving our four stratigraphic units,
to which I will assign a material.
The bottom most layer is assigned a bedrock material,
and then the overlying units in turn
include, clay, gravel, and aluminum.
Prior to the start of this webinar,
I imported an as-built design drawing
via the import body tool.
In the design history,
I will right click the profile and unsuppress.
The cross section of the downstream tailings dam
and tailings is now visible.
I’m going to click on the profile
and subdivide the tailings into a number of layers.
I’m doing this simply for the purpose
of conducting a geotechnical technical analysis.
For simplicity, I will split the tailings into five raises.
BUILD3D is a feature-based geometry creation tool,
so we can edit this sketch at any time
and all the changes are automatically cascaded
through the entire model’s geometry.
With the drawing complete, I will hit okay.
And the geometry is regenerated.
Notice that the as-built section
is located at the center line of the valley.
In preparation for an extrusion,
the location of the section needs to be offset.
Right clicking the profile and editing
reveals the original location of the plane end profile.
I can change the offset to sit inside the domain,
This position moves the profile inside the ground surface.
It will become apparent when I extrude the profile
that our goal here is simply to ensure
that the geotechnical structure traverses the entire valley
in a manner consistent with the actual construction.
With the tailings dam profile
now located inside the upper ground surface,
I will right click the profile and select extrude.
The extrusion distance is arbitrarily set to 50 meters
and then 100 meters, causing the extruded profile
to span the entire valley.
Notice the shadow-like image that shows
the intersection between the structure
and the ground surface.
After rotating the camera angle,
I’m going to select the solids that represent
the tailings dam and create a group.
The material for this group of solids is then changed
and the process is repeated for the tailings layers.
We see the fill material listed in the drop down list.
And then, again, I’ll select these next five solids
for the tailings layers,
create the group and rename it.
Select the group
and then change the material type.
Clicking in the geometry explorer
reveals that the solids extend into the flanks
of the valley wall.
I therefore need to remove this portion of the tailings
and dam geometry using the cut tool.
In this case, the first and second stratigraphic units
are used as the cutting tool
and the option to remove the overlapping solids is selected.
Once the operation is completed,
I can select the upper stratigraphic layer
and note visually that the tailings structure
does not extend into it.
I do this by first toggling off the surface selection tool
and then selecting only solids.
At this point in the workflow,
the analysis ready geometry is complete.
We could now proceed to mesh the domain,
then return to the geometry definition,
apply boundary conditions, and then solve the analysis.
We can see now that the finite element mesh is complete.
I’m switching back to the geometry view,
selecting the surface of the tailings,
and applying a hydraulic boundary condition.
Conversely, we could create a two dimensional analysis
based on the 3D geometry and poor water pressure conditions.
To do this, I select the geometry section tool.
Once the location has been selected,
I can hit okay,
navigate down to the geometry sections area,
right click, and generate 2D GeoStudio geometry.
Closing BUILD3D and going back into GeoStudio,
we now see a 2D geometry in the analysis tree,
to which I will add a slope/w analysis.
Note that the materials are automatically mapped
to the regions.
Accordingly, I can click on define, materials
and the list of materials is populated
by simply defining a material model
such as Mohr-Coulomb,
we see the colors of the materials mapped to the regions.
Now we come full circle to the heart of the issue.
We have a 2D and 3D geotechnical analysis,
which together, with the geological model,
form a comprehensive digital twin.
As noted at the onset,
evolving site conditions and new data
could cause the geological model to change.
We need to ensure that the geotechnical analysis
is based on the most up-to-date site model.
In Leapfrog, the geological model
is dynamically updated by introducing new information,
such as geophysical data, polylines,
design drawings, and more.
For demonstration purposes,
let us simply assume that an error was observed
in the borehole data.
Notice that the stratigraphic layers
are not smooth and continuous in this profile.
I’m going to open the borehole log data
and alter the stratigraphic contact depths.
I’ll quickly do this by changing the depth to the contacts
in boreholes 10 and 12.
After saving the file,
I will reload the borehole data
and then reprocess the geological model.
So first, reload the boreholes.
Then, navigate to the play button on the top left
and select run all.
The geological model is updated
as indicated by the new, smoother geological contacts.
Looking at the slice from the backside
reveals nice, smooth, continuous contacts.
Then, rotating the camera view around to the front
similarly demonstrates that the geological model
has been updated.
After publishing the Leapfrog model to Central,
I can now return to GeoStudio
and reload the background meshes
used at the onset to create the analysis-ready geometry.
I do this by multi selecting three surfaces,
right clicking, and reloading.
We can see in the bottom right of the tray
that the Boolean operations are being recomputed.
This is a key advantage of a feature-based modeling package
like BUILD3D, because any change to the model
is automatically cascaded through the design history.
Once complete, we can switch over to the mesh view,
remesh the domain,
and then I will use the clipping tool
to inspect the updated geology.
The process takes just a couple seconds
to recompute all the contacts and update the model.
Again, the clipping plane tool,
much like a sectioning tool,
allows us to look inside the domain.
Notice that the contacts have all been updated
and they’re now nice and smooth.
With this new clipping plane,
I will change the camera view.
We see the clean geology and the new contacts.
Then I will navigate to the 2D geometry section
back on the geometry window.
First shutting off the clipping plane,
then switching back to geometry view,
scrolling down, selecting our section,
which runs down the center line of the valley,
I’ll right-click, generate a new section
which replaces the old section.
I can then close BUILD3D.
And back in GeoStudio,
when I click on the slope stability analysis,
we see the new geology are reflected
in this cross section.
In summary, teams have to think about
a holistic modeling approach
with the digital twin at its core
in order to manage tailing storage facilities safely
and consider the requirements
of the global tailing standard.
The digital twin becomes the basis for design
used at all phases of the project’s life cycle.
It invites the engineers to participate
in the investigation of the physical system,
to understand the geological constraints,
and make informed decisions about the facility’s
performance as it evolves.
A comprehensive and dynamically updated digital twin
consistently incorporates changing data
and evaluates all spatial, numeric,
and intellectual information in a 3D context.
It can also help design targeted monitoring programs.
Interpreting monitoring data is a significant challenge
as it goes beyond plotting a time series of data.
Again, data is only valuable if it is interpreted
in the context of the digital twin.
Thank you for your time and attention.
We look forward to welcoming you again
in mid-July for the third part of our webinar series.
Dr. Yanina Elliott will discuss an agile workflow
that accommodates stakeholder engagement.
This will bring together all the key components
of the Seequent ecosystem to demonstrate
how owners, analysts, engineers of record, and auditors
can collaborate on the management
of a tailing storage facility.
Thanks again, and have a great day.