Coal beds usually are easy to identify from well logs. They exhibit very large acoustic interval transit

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times, very low densities and very high neutron porosity indices. At the same time the natural gamma ray deflection is very low and the resistivity high.

Because the properties of coal are so distinctive, logging data are of considerable use in evaluating the coal bed itself. For example, methods have been developed to derive percent ash, percent moisture, and percent fixed carbon from log data.

Planning a coal mining operation is an extremely important phase, particularly for subsurface mining. Processed logging data can provide information on the strength and lithology of the adjacent formations; this will help to obtain a safe and economical mine design.

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