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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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Fact, Truth and the Scientific Method

  Is there a sense in which a geological map can be described as a representation of fact? Can a map define “ground truth?” A map is a virtual reality representation of the world in two dimensions. A geological map is a human artefact constructed according to […]

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Map scales

The most fundamental feature of any map is its scale. The scale of a map is the ratio of a length of a unit line on the map to the length that that line represents in the real world.   The ratio is expressed as a fraction that […]

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The impossible diamond drill hole

Here’s a geological mystery. The impossible diamond drill hole - a drill hole drilled where no hole could possibly be drilled. I can offer no really satisfactory explanation, although there must of course be one. Perhaps readers can think of one for themselves. A few years ago I was […]

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