Category: Hints and tips

Building a geological model – Part 2 of 3

By Andrew Cantwell

This video continues on from part 1 of building a geological model in Leapfrog.

You won’t hear any narration in this video but captions have been provided to explain the basic steps. If you’re after a more detailed description of the model building process then please contact your local support team.

We recommend you view this video in full screen mode. It may take approximately 30 seconds after you press play to switch to High Definition (given your internet connection allows it)

The main steps in this video on building a geological model include:

  • How to create a new geological model
  • Creating depositional surfaces
  • Editing a surface using a polyline
  • Activating surfaces to produce volumes
  • Creating dykes
  • Editing interval selections
  • Adjusting the chronological order of the surfaces
  • Creating intrusions

If you missed part 1 you can view the post here

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Grade shells vs. mineralised zones

By Lisa Swinnard

There is more than one way to create a boundary surrounding a cut-off grade in Leapfrog; however the different techniques used to create these boundaries rely on different underlying concepts. Which tool to select will depend on the ultimate purpose for building the boundaries.

The typical way to create these boundaries is by building grade shells using the Interpolant tool in Leapfrog. Interpolated grade shells are built by using the known drillhole or point data to interpolate values infinitely across the boundary extents; isosurfaces (grade shells) are then created to link up identical values. Grade shells created by interpolation represent a “soft boundary”, as it is not possible to snap these isosurfaces (grade shells) to contact points on drillholes. Grade shells created using interpolation are ideal tools for exploration drillhole targeting.

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Making a scene – Leapfrog Saved Scene

By Sam Bain

Imagine you have built an amazing geological model. You have identified and fixed the problems in the core logging, you have reconciled the lithology labels used by the different historical surveys of the area, your geological surfaces are consistent with the data and make geological sense, your grade model has been built taking into account the geological structures and you are happy with its predictions. Is that your job done? No, of course not.

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Predictions at locations where there are no measurements

By Richard Lane

A key feature problem in geological modelling is how to take scattered measurements and use these to make predictions at locations where there are no measurements. The data may be measurements on the surface, or samples taken from drilling, or channel samples taken while excavating. Figure 1 shows the basic problem. Solving this problem is fundamental to how Leapfrog software works, and it underpins the geological and mineralization models that are produced.

Figure 1: A simple scattered data problem. Estimate the value at the red cross from the blue samples.

Figure 1: A simple scattered data problem. Estimate the value at the red cross from the blue samples.

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Interpolation and anisotropy

By Kirk Spragg

Introduction

In addition to interpolation, Leapfrog provides two tools that give the user control over the continuity of grade in their interpolants. These are the “Global Trend” and the more advanced “Structural Trend”.

The Global Trend can be effectively used to alter the results of an interpolant.  The Global Trend  is suitable to use in situations where the underlying geology implies that grade is continuous in a planar direction over large distances. If this is not the case, and the underlying geology implies that direction of grade continuity varies over space, then Leapfrog’s Structural Trend is a more appropriate tool to use when modelling your deposit or ore body.

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Viewing multiple images projected on topography

By Sam Bain

Leapfrog allows users to import a range of images into a project so they can be viewed on topography. These include but are not limited to topographic maps, satellite imagery, aerial photos, and geological maps.

Imported images can be viewed projected on topography by adding the topography to the scene and then selecting them from the GIS data drop-down box below the topography object in the shape list (Figure 1).

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Modifying your drillhole data: Interval Selections

By Sam Bain

The “Interval Selection” tool in Leapfrog combines most of the abilities of Grouping and Splitting (as discussed in previous blogs) with fewer restrictions. The Grouping and Splitting tools provide workflows for combining or splitting existing lithologies exclusively. The intervals selection is ideal when elements of both the grouping and splitting workflows need to be combined. For example, perhaps assay data indicates some intervals have been incorrectly logged and need to be assigned to a new lithology. If these intervals have been logged as several different lithologies then they need to be split from their old lithologies and then grouped to a single new lithology. The interval selection tool allows you to do this.

Figure 1: Right click the interval table and select the "Interval Selection" option

Figure 1: Right click the interval table and select the “Interval Selection” option

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Modifying your drillhole data: Splitting lithologies

By Sam Bain

The “Split Lithology” tool (available in Leapfrog Geo, Geothermal, and Hydro) creates a new lithology column by sub-dividing lithologies in an imported column. Often simple logging will result in repeating intervals on each drillhole and these will need to be separated for modelling purposes. As an example, perhaps three unique limestone units at different depths are encountered by exploratory drilling. These might all be logged simply as “Limestone”. In this case the splitting tool could be used to divide the “Limestone” intervals into “Upper”, “Middle”, and “Lower” units. Then each unit can be modelled separately. It is important to note that the original logged intervals are preserved, and the new splits are made in a new interval column. The modeller can correct or re-interpret the logging without altering the original field data.

This blog explains how the “Split Lithology” tool works by walking through a simple example.

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Is expensive video hardware for Leapfrog worth the cost?

By Kirk Spragg

The retail cost of video hardware is not a reliable guide to how well Leapfrog’s 3D visualisation functionality performs on that hardware. The more expensive workstation grade hardware solutions such as NVIDIA’s Quadro range of desktop cards are designed to accelerate operations that Leapfrog does not use. As a result, the 3D performance in Leapfrog is often no better than less expensive gaming and home grade video hardware.

In this post Applications Specialist Kirk Spragg compares five home and gaming grade video cards with a workstation grade Quadro 4000 by benchmarking the cards to determine their relative performance.

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Compositing numeric and assay data in Leapfrog Geo

By Kirk Spragg

Compositing numeric and assay data

Leapfrog Geo allows users to easily manipulate drilling data. This blog, written by Applications Specialist Kirk Spragg, explains the process of compositing numeric data. Numeric data compositing takes numeric data that is unevenly spaced down drillholes, and turns it into data that is regularly spaced down the same drillholes. In this article, we explain the separate stages of the compositing process in detail. We also show you how Leapfrog Geo’s compositing algorithm works.

The compositing process

The compositing process is performed in three stages:

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