TARGETING DRILL HOLES It is a truism that ore bodies are rare and hard to locate. If this were not so, they would hardly be worth finding. Explorers search for them by drilling holes into the ground. A single drill hole produces a very small sample […]
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The Three Point Problem In a previous post (see here) I described how quantitative orientation data can be collected from from a single drill hole, even where the core is not oriented. In this post, techniques for collecting orientation data on planes are described when more than one […]
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Measuring Structure in Non-Oriented Drill Core My drill core is not oriented. How do I measure structure? Down-hole orientation surveys record the deviation of a drill hole from its initial azimuth and inclination. However, the solid stick of drill core (sometimes, not so solid) recovered from a […]
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The Specific Gravity (SG) of a substance is a measure of its density. It is expressed as the ratio of the weight of a given volume of the substance compared to the weight of an equal volume of a reference substance – usually water [1] . An […]
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Six rules for alpha beta measurements in drill core It is always better to know the orientation of planar structures at the time of logging rather than at some later date when the structure that was measured is long forgotten and the core returned to its stack in […]
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This post, the third part of a series (for parts 1 and 2 see here and here), is about the appearance of common geological structures on the surface of diamond drill core. Visualising complex objects in three dimensions isn’t easy, although geologists are better at this than most. Two dimensional […]
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MAKING SENSE OF 2D DATA – PART 2: FOLDS This post is the second of three parts (for parts 1 and 3, see here and here) and describes the different appearances which folds can have depending on the orientation of the surface on which they are exposed. […]
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Diamond drilling of a prospect typically goes through two phases. The required geological inputs for the two phases are different. The first phase comprises initial exploration drilling ‑ the target generation and target drilling exploration stages. In these stages drilling is aimed primarily at a geological understanding […]
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The camera and the interrogator How odd it is that anyone should not see that all observations must be for or against some view if it is to be of any service. Charles Darwin, 1870 Speak to exploration geologists and you will find two views about what a […]
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Vergences and fractals Field geologists have long known that the style and relationships of structures seen in a hand specimen, outcrop or drill core can mimic the style and relationships of much larger structures that formed during the same deformation but occur at the scale of a geological […]
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