Inorganic elemental variations factors

The purpose of this paper is to provide a critical interpretation of coal inorganic elemental data in the literature. Several valuable compilations of elemental data exist for U.S. coal (1-4). We have borrowed freely from these compilations to illustrate their value in elucidating just one aspect of coal geochemistry the factors influencing inorganic elemental variations. 

It is hoped that this paper will encourage more detailed study of factors influencing inorganic element variations in coals. Acknowledgment... 

This general review of factors influencing major, minor, and trace element variations in U.S. coals provides an interpretation of coal inorganic elemental data found in the literature. Variations due to ash-related, rank-related, geochemical, and geological factors are discussed. 

Inorganic element concentrations in coal show variations from a microscopic to a worldwide scale. From a resource evaluation perspective, the most significant variations occur within and between coal seams and basins. The rest of the paper will discuss factors that cause these variations. 

Ash Related Variations. The amount of ash in a coal is a major factor influencing inorganic element content. In general, trace element concentrations increase as ash content increases. This relationship reflects the fact that most inorganic elements in coal are associated with minerals (7). Figures 1 and 2 illustrate this relationship for K in eastern Kentucky coals and for Ti in coals from the Uinta Region in Colorado. 

Variations Due to Geochemical Factors. Geochemical factors, such as Eh and pH of the peat environment, as well as the environment during and subsequent to coal formation, can have dramatic effects on inorganic element content. The effect of these geochemical... 

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