Tag: drillhole

Drillhole planning in Leapfrog Geo

By Andrew Cantwell

One of the major costs of an exploration project is the drilling program. Planning drillholes in 3D based on existing knowledge is an easy way to maximise the value of any future drilling, and can be achieved quickly and easily in Leapfrog Geo. This blog post will take you through the steps required to plan a drilling campaign in Leapfrog Geo, then set up a scene file so the field team can see where each drillhole should be going, as well as what lithology and grade it is expected to intercept, in 3D.

  • The first step is to define your project area – a good start is to import any existing data. This could include a topography surface, any existing drillholes, an aerial photograph or geological map, and GIS data such as lakes, rivers, access roads and tenement boundaries.
  • Once you have imported the existing data, you’ll be able to start visualising in 3D where an appropriate location is to place your collar. If you’ve created any geological or grade models, you can also visualise where your potential target is.
  • To create a planned drillhole, right click on the ‘Planned Drillholes’ folder, and click ‘Plan Drillhole’.
  • There are two options you can choose; you can either specify a collar location or a target location. We’ll specify a collar location as it is more common to have a known point on the topography to place your collar.

Example 1.

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Leapfrog Geo evolves with the release of 1.4

By Tim Schurr

The geological modelling workflow platform has evolved again, allowing you to model more geologies, in so many more ways. Earlier this month we released Leapfrog Geo 1.4, the third iteration of the software since its launch in February this year. The development group in New Zealand has been working full tilt at two key objectives; to extend the flexibility of Geo and to expand its capabilities with new workflows. The result is a new benchmark in usability and modelling workflows that delivers functionality that modelling geologists really need. So what’s new in version 1.4?

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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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The dark art of drillhole desurveying

By Richard Lane

Desurveying computes the geometry of a drillhole in three-dimensional space based on its collar location and the raw dip (or inclination), azimuth (or direction) and depth data of one or more surveys. The resulting geometry is a polyline – a connected series of (X, Y, Z) coordinates used to find the composite locations.

Only under ideal conditions will the path of a drilled hole follow the original dip and azimuth established at the top of the hole. It is more usual that it will deflect away from the original direction as a result of layering in the rock, the variation in the hardness of the layers, and the angle of the drill bit relative to these layers. The drill bit will be able to penetrate the softer layers easier than the harder layers, resulting in a preferential direction of drill bit deviation.

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Leapfrog interpolation basics

By Kirk Spragg

Introduction

The Leapfrog software suite uses a mathematical method called interpolation to produce dynamic implicit models.  An interpolation tool, FastRBF™ has been specifically developed by ARANZ Geo. FastRBF™ has revolutionised the way geologists produce geological models, as it dramatically speeds up the process and allows models to be updated dynamically. Although the mathematical details of how FastRBF™ works are somewhat complicated, the basic idea is relatively simple. This blog explains the process using simple examples.

Interpolation is a method that produces an estimate or “interpolated value” of a quantity which is not known at a point X say but is known at other points such as from drillhole data.  With the user’s expert guidance, Leapfrog uses FastRBF™ to “interpolate” or fill in the gaps where there is no data.  This is how Leapfrog creates deposits, intrusions and grade shells from the user’s data. Since FastRBF™ is fast, results can be quickly updated when new data is added, ensuring the implicit model is dynamic.

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