Coal

Abstract

Coal is formed by the accumulation and preservation of organic material (primarily from plants) in swamp, marsh, or bog environments. This plant material is altered into peat by complex biochemical processes. The level of coalification attained is primarily a product of temperature and length of time of heating. Because in most stratigraphic sequences temperature increases uniformly with depth, the more deeply buried coals are generally of higher rank. As rank increases, porosity, volume, volatile constituents, and water decrease, while fixed carbon, density, heating value, and reflectance increase. A discussion touches on the more commonly used types of analytical data from the view-point of the information they convey to the explorationist about the suitability of product for certain end uses.