Methods of Exploration

Methods of exploration are indirect methods, semi-direct methods and direct methods of exploration.

1. Indirect Methods

Indirect methods consist of geophysical and sounding methods. In these methods, depths to the principal strata are established based on some physical properties of the material, and the measurements are made on the ground surface. No samples are obtained in the geophysical methods, but in some sounding methods, representative samples are obtained.

2. Semi-direct Methods

Semi-direct methods are common boring and drilling methods combined with intermittent sampling. The depths of different layers are ascertained by the rate of advertisement of boring tools or by means of non-representative samples obtained in the course of boring operations. Borings provide access to a particular layer of sampling. In general, only major changes in the character of the sub-surface materials can be detected by this method. The different boring methods are wash boring, rotary drilling and auger boring.

3. Direct Methods

Direct methods are boring and sampling methods which continuously provide representative or undisturbed samples. All accessible exploration, such as test pits, trenches, large diameter boring, shafts, drifts, etc., are grouped under direct methods. These accessible explorations allow direct examination of strata in-situ.