Using VOXI Geophysical Inversions to Aid Exploration

Overview

Video Transcript

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<v ->Hello, good morning, everyone.</v>

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It’s great to see everyone here at Lyceum 2019.

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My name is Geoff Plastow and I’m a Project Geophysicist

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based here in Vancouver.

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And throughout the course of the day,

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we are going to hold several tips and tricks sessions.

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So I’m excited to kick off our very first session.

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Okay, so this morning,

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I’m going to talk about geophysical modeling

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and how we can use geological inputs

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to help us constrain and improve our geo-physical models.

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This afternoon, my colleague Anna is going to be working

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in Leapfrog Geo,

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and she’s going to show a few tips and tricks

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on how to do quality control

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and how to better manage your drill holes.

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And later at the end of the day, my colleague,

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Sarah is going to be working in Leapfrog edge.

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And she’s going to show you some best practices

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regarding resource estimation.

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So when we were planning this event, we were thinking about,

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it’d be more interesting if we told a more compelling story.

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So throughout the course of the day,

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we are going to be working through what we called

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as mining value chain.

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We were working through exploration to resource evaluation.

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So this morning, my tips and tricks session is based

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in the top left-hand corner,

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where we are talking about prospecting,

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geophysical prospecting.

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We are boots on the ground and we’ve collected

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maybe a few holes.

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We’ve, collected three drill holes,

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and we’re going to look at some geo-physical models

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that we’ve created and ways that we can constrain it.

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Later in the day, my colleagues,

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Anna and Sarah are going to be working in Leapfrog Geo

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and Leapfrog age, Leapfrog edge

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a little further down in a mining chain.

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So this morning I’m going to be working in app.

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So it’s going to be exciting.

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Okay, so the first application I’m working in

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is called Central Browser.

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Central Browser allows you to connect

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to your central server.

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And what that allows you to do is to view and to manage

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the history of your geologic and earth models.

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So we can see on the left-hand side of the screen,

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we have a number of nodes and each one of these nodes

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represents an iteration of your model.

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And it’s great for a geophysicist like myself,

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because I can always go in and I can see how the model

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has evolved and progressed over time.

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And if I want, I can create my own branch

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to kind of keep my geo-physical models

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from interfering with other geological models.

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So if I click on this branch here, I can just pop it open.

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And my colleague Anna was great enough

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to create a little annotation.

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She says, Jeff, can you take a look at this?

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She’s drawn a straight plane through

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this massive sulfide body that started drilling,

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we’ve sunk three drill holes,

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and we’ve intercepted this massive sulfide twice.

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And she’s saying, Jeff,

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is it possible for you to incorporate any of this

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information into your geophysical modeling?

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Well, of course, that would be great.

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So the first thing I’m going to do

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is I’m just going to right click and export this

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export this geological model.

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And I’m just going to select the elements I’m going to export.

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So I’m exporting our MV volcanics, our LMS two,

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which is our sulfide body and the overburden.

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So I’m just going to export that,

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oops, okay.

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So once it’s been exported,

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I’m just going to jump into Oasis montaj.

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Now Oasis montaj is another desktop application

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that’s well known for the integration

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of all types of geoscience information.

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This includes geology, geophysics, geochemistry.

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In this case, we are really going to focus in on the geophysics

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and the geophysical modeling component of Oasis montaj.

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So to start off,

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I’m what we’re looking at is geophysical data

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that we’ve collected over the survey area,

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over the area of interest

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where we’ve already done some drilling,

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the data we’re looking at is magnetic data.

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So what we’ve done is we’ve collected

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total magnetic intensity.

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And what we’re looking at is areas in pink and red

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represent areas that are of high magnetic intensity

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and areas that are cooler in color

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in blue represent areas that have a low magnetic intensity.

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And I’ve just draped this over some topography

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and I’ve imported the drill holes

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that we have already looked at in the Central Browser.

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So the first thing I’m going to do now

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is now I’m just going to import our Leapfrog model.

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And I’m going to assign a projected coordinate system to it,

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just to ensure that everything lines up as it should.

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So the good news is that it imported

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and it looks exactly like it did in Leapfrog Geo,

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and also in the Central Browser.

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So I’m just going to turn off our volcanics

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so we can see our overburden here in this brown or orange.

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And we can see our green sulfide body here penetrated

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by two drill holes.

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Okay, well, this is exciting, what else can we do?

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So I’ve already performed an unconstrained

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geo-physical model.

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And what I’m going to do is I’m just going to visualize that now.

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So what do I mean when I say

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an unconstrained geophysical model,

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what I’ve done initially without any information

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is I’ve created a geo-physical model with no constraints.

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I’ve provided no geologic input.

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I’ve provided no geo-physical input and I’ve just created

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a model as a first pass.

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So let’s see what it looks like.

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So we can see some large pink blobs,

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which represent areas of high magnetic susceptibility.

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And I’m just going to slice through this box, a little bit.

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Okay, great.

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So we can see this large pink geophysical response

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of high magnetic susceptibility,

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more or less correlated with our sulfide mineralization.

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Okay, that’s great news.

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But the reality is we know that this mineralization

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does not extend all the way to the surface

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and the anomaly itself is rather blown out.

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Now, blown out is not a real technical term.

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I’m just saying that it is significantly larger

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and its physical extent is much larger

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than the mineralized body.

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We know that we can do a lot better.

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So why don’t we try to incorporate

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the geological information

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that I’ve just imported into Oasis montaj?

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So I’m going to open Voxler.

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Voxler is the geophysical modeling component

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inside of a Oasis montaj .

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And I have a model space here.

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This is just what we call a model mesh.

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And what I’m going to do now is build a very quick constraint

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from our Leapfrog model to do that.

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I can click constraints, create, build a model.

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So here I have the ability to assign physical rock

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properties to each one of the elements

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of the Leapfrog model.

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In this case, maybe we don’t have a great understanding

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of the magnetic susceptibility.

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So maybe we’re just going to use regional values

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or we’re going to maybe even use textbook values.

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So I’m, I can assign sub magnetic susceptibilities

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to our overburden layer

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and I can assign magnetic susceptibilities to our sulfides.

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I’m going to click, okay.

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Okay, so we’ve created our very first constraint

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from this Leapfrog model.

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We can see here in the blue,

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we see our overburden susceptibility

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and then we can see this susceptibility values

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that we’ve assigned for a massive sulfide body here in pink.

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Okay, great.

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So now we’ve at least provided some physical distribution

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of rock properties that can help us guide our inversion.

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So what I can do now is I can just click this green button

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and run the inversion.

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So the good news is I’ve already run the inversion.

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Voxler runs the inversion in the Cloud.

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It doesn’t use any of your computer resources.

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And in this case it took about an hour.

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So what I’m going to do now is I’m going to visualize

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both the constrained and unconstrained model.

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Okay, so we have our constrained inversion.

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So the model I just created on the right-hand side

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and on the left-hand side,

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we have our original unconstrained inversion.

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So what do we see between these two different earth models?

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So first off, right away, we can see this pink,

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highly susceptible content near surface.

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This is what we expected.

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We told the inversion that we have an overburden

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and we’ve assigned some magnetic susceptibility to it,

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that’s great.

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So now what happens if I spin the model around

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and begin to slice through it?

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So I’m slicing through our constrained inversion

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and we are looking in the area of where we’ve drilled

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and now we see a geo-physical anomaly

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that’s much more constrained.

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It’s much more in line and much more in line

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with our sulfide mineralization.

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The anomaly itself is a little bit larger

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than maybe what we expected,

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but this is pretty good for a first pass.

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So what I’m going to do is I’m just going to spin it around

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again here,

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and I’m just going to clip some of the data values to see,

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how well we recover the overburden and sulfide body.

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So we can see here in pink,

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we see that we’ve recovered more or less what we told it to.

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And we’ve now sort of limited the extent

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of our sulfide mineralization.

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Okay, well, this is great.

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How do I convey these results back to my colleague, Anna,

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who originally sort of created this model?

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I can simply just right click and I have a number of options

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to export and share this model.

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I can upload it to sequent view or I can export to OMF

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OMF stands for open mining format.

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If you want to know more about opening mining format,

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feel free to talk to any of our staff members

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during the solution kiosks.

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So once I export to OMF,

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I can jump back into the Central Browser

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and I can simply send a quick attachment to Anna.

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I can just say, here is a constrained model.

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Hopefully I type that correctly and I can attach to the OMF

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export and I can simply publish this model.

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And next time Anna’s back in the Central Browser,

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she can see that I’ve made an update and she can now begin

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to integrate these updated model into her geologic modeling.

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So to summarize this sort of tips and tricks

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that I’ve talked about this morning.

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The Central Browser is a great location for sharing

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and managing your geoscience data.

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Even geophysicists can go in there and export models.

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We can import these into Oasis montaj and they open

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just like, just like they look just like they do

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in Leapfrog.

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We can use these geologic inputs to constrain

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these geophysical inversions

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and produce much more realistic earth models.

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And then we can share them back with our colleagues

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and geologists and geoscientists

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who are using the Central Browser.

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And we can create a bit of a feedback loop

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and we can constantly update our geologic models

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and geophysical models working together.

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So this concludes my tips and tricks session.

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If you have any questions about anything I mentioned today,

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feel free to just talk to me during one of the breaks.

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Thank you.

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(crowd clapping)