Source and Distribution of Phosphorus in British Columbia Coal Seams

Phosphorus contents of coal from around the world vary although there is a tendency for Permian coals from India and Australia, and Cretaceous coals from Western Canada to have more phosphorus than Carbcmiferous coals from Europ+ and USA (Table 1). This may be because of the evolution of vegetation type over geological time or because of the conditions in the coal swamps. Data presented here suggest that most of the phosphors in coal derives from the original vegetation and, in fact, the :amount of phosphorus in coal may be less than expected based on its concentration in vegetation. How the phosphorus is removed from the coal is less clear although a number of possible methods are suggested that i,nfer broad distribution patterns of phosphorus in various lithotypes and macerals. In some cases there is evidence to indicate that phosphorus is concentrated in the inert mace&, but in other cases the evidence is contradictory or ambiguous. Phosphorus is generally considered an undesirable element in steel,, which it makes brittle. It can be removed from the hot metal used to make the steel, but companies generally prefer to control the amount entering the steelmaking process. Phosphorus originates in the iron ore, siuter pellets and in the coal used to make blast furnace coke. Steel mills have limited sources of supply of iron ore but can buy coal from a number of suppliers They therefore sometimes give preference to coals with lower phosphorus contents, and the phosphorus content can have implications on the marketability of toal for coke making. This is generally not the case for thermal coal in which phosphorus contents ranging from 0.1 to 124 P20s in ash may be acceptable (Skorupska, 1993). Limited data indicate that phosphors is difficult to remove from coal by conventional washing techniques. It is therefore important, in metallurgical coal mines, to understand the distribution of phosphorus in the coal seams, because blending of the run of mine (ROM) coal, rather than washing, may be the best way of controlling the amount in clean coals. Data collected during this study are not identified with respect to any particular mine and scams are identified by letter, starting with A at the base of the Mist Mountain Formation. The lettering system does not correspond with the seam numbering in any particular