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Drill Hole Targeting

  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: Calculating strike and dip from multiple DD Holes

The Three Point Problem In the previous post I described how quantitative orientation data can be collected from non-oriented core from a single drill hole.  In this post, techniques for collecting orientation data on planes are described when more than one non-oriented hole is available from a […]

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Measuring Structure in Non-Oriented Drill Core

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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How to measure the Specific Gravity of rocks

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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Five rules for use of alpha-beta measurements in drill core

Measurement of planar structure such as a bedding plane a vein or a cleavage in oriented diamond drill core can be done in two ways. The simplest way is to set up the core in its original orientation by means of a core frame and then measure […]

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Making Sense of 2D Data – Part 3: Structures in Diamond Drill Core

This post, the third part of a series, 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 objects are an order of magnitude easier to […]

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Making Sense of 2-D Data : Part 2 – Folds

MAKING SENSE OF 2D DATA – PART 2: FOLDS This post is the second of three parts and describes the different appearances which folds can have depending on the orientation of the surface on which they are exposed. Visualising complex objects in three dimensions isn’t easy, although […]

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Making sense of 2-D Data – Part 1: Faults

Visualising complex objects in three dimensions isn’t easy, although geologists are better at this than most. Two dimensional objects are an order of magnitude easier to comprehend. Where the object under study is complex we can gain an understanding by visualising or portraying two dimensional slices across […]

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Diamond drill core logging

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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Ore bodies are created, not found

Ore bodies are created, not found There is a widespread belief amongst people outside our profession that all ore bodies that have yet to be found already exist. They are imagined as out there, ready-made by nature, waiting for some lucky prospector or mining company to stumble […]

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