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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Interpolant function in Leapfrog Geo

By Tim McLennan

Choosing an interpolant function

Leapfrog Geo uses two different base functions to form interpolants. They are the linear interpolant function and the spheroidal interpolant function. This blog covers when to use each base function, how to set the function parameters, and how to convert the parameters for a Leapfrog Mining interpolant across to Leapfrog Geo.

As explained in the Leapfrog Interpolation Basics blog article, the interpolant functions indicate how the function values are expected to vary as the distance between points increases. At small distances the values are expected to be similar and so the function values are small. At large distances the values are expected to vary considerably and so the function values are larger.   The nature of this relationship means that the interpolant function is equivalent to the variogram used in geostatistical modelling.

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Video guide – How to share assay data from Leapfrog Geo with ioGAS

By Sam Bain

ioGAS software allows its users to identify geochemical relationships within assay data. With the newly released ioGAS Link, a live link between Leapfrog Geo and ioGAS, you can easily incorporate geochemical data into your geological modelling process. The geochemical relationships identified in assay data can be used to refine existing geological models and define new geological units.

This video demonstrates a workflow that allows you to share assay data from Leapfrog Geo with ioGAS. Once the live link is opened, the assay data is shared with ioGAS. The TAS plutonic diagram within ioGAS is then used to identify geochemically defined lithologies. The newly defined lithologies are transferred back to Leapfrog Geo and used to create new geological surfaces. The new geological surfaces are compared to the units identified by field logging. As you will see, there are significant differences!

While this is demonstration data, it illustrates the potential benefit in using assay data to cross-check the field logging of drillholes.

For more information on the ioGAS Link visit the Leapfrog website.

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Modifying your drillhole data: Grouping

By Sam Bain

A standard workflow in Leapfrog is building a geological model from the interval columns of imported drillholes. This workflow requires the importation of a collar locations file, a survey file with drillhole geometry, and an interval table with the observed lithological contacts. In addition, other down-hole information such as from geophysical logging or drill core assays can be imported as interval tables.

Often there will be problems with the drillhole data. Perhaps the logging in the field was inaccurate and two unique units were incorrectly lumped into one. Of course, the opposite could happen if an eager geo sub-divides a single sandstone deposit into separate poorly sorted and well sorted units. In these situations, the drillhole data needs to be edited so that a new unit is defined or existing units are combined. The “Group Lithologies” and “Split Lithologies” tools in Leapfrog allow you to create a new interval column based on edits of an existing interval column. An additional tool called “Interval Selection” has been developed that uses elements of the grouping and splitting workflows to create a new interval column. In this post we will look at the “Group Lithologies” tool.

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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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Tech Services – Who we are

By Dion Blair
The-Tech-Services-team-in-front-of-the-map600
Our New Zealand based Tech Services team: Andrew, Peter, Alice, Winnie and Dion

A team of geologists providing global support

Tech Services evolved from the need to offer a support capability to a team of four offering far more – case support, training, project assistance and dealing with licence renewal within their territory. In late 2011 working out of their third office since the Christchurch earthquakes, Tech Services hired their second Tech Services Rep (TSR), a third followed in January 2012, a fourth in April and a fifth in July. The New Zealand Tech Services Team farewelled its most experienced TSR, Jacob de Lacey in September 2012 so he could build the Tech Service offering in Perth. Another experienced TSR, Clare Baxter, moved to become part of the Perth team in November 2012.

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Drillhole Data Errors: Acknowledging a reality and dealing with it

By Sam Bain

Introduction

Everyone would like accurate and correct data. A lot of money is spent on trying to ensure the accuracy of data, whether it is from core logging, field mapping, or geophysical surveys. However, the reality is that mistakes and accidents will happen and some data will be wrong. Accepting that errors are always going to get in somehow, it makes sense to create systems and software that identify these errors, and then provide the tools to fix them. Good software packages help deal with data quality by identifying common errors on import of data and providing automated correction of these problems. Ideally there should be a person in the loop to ensure the identified data is an error and to decide how they should be dealt with.

Leapfrog software automatically highlights recognised data errors and in most cases provides automated or semi-automated correction tools for you. The principle source of errors is drillhole information and the drillhole interface prominently highlights recognised issues and offers you the ability to correct errors. Leapfrog software will also recognise errors and potential errors in imported locations and prompt user input to fix them.

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