The potential of coal wastes in South Africa

There are few data on the composition of discard coal in South Africa, and no overall view of the discards for the entire industry. As a result of wor k on coal qualities in South Africa, a database was established which enabl ed a good estimate to be made of the composition of the discard from every mine. The data are presented in the form of histograms of ash, volatile mat ter and fixed carbon content of the 43 million tons of material which were discarded in 1990. The results are discussed in terms of the closeness of t he composition of much of the discard material to presently used power stat ion coal. It is concluded that it is mainly developments in equipment, part icularly fluidized bed boilers, which inhibit the wider use of discard coal . However, other factors must be noted, including the relatively high sulph ur content of the discards, and the fact that even with the most careful st orage the material ages and may become unusable after about 15 years.