Properties of Fly Ash Used As A Topsoil Substitute In Mineland Reclamation

摘要

Fly ash, used as a topsoil substitute, may provide a desirable alternative to conventional methods in the reclamation of adverse mine sites such as abandoned mine lands (AML) and coal refuse in the eastern United States. In August 1987, fly ash from three different power plant sources was surface-applied as a topsoil substitute at a rate of 1,200 metric tons/ha on an acidic minesoil representative of AML in northcentral West Virginia. In May 1990 (3 years after reclamation) and June 1999 (12 years after reclamation0 both fly ash treated and untreated minesoil plots were sampled and analyzed for selected soil properties. Resutls indicated substantial differences between minesoil and fly ashes for most of the soil properties examined. Fly ashes had lower bulk density and higher percentage of mesopores (0.0002-0.01 mm) and lower percentage of micropore (<0.0002 mm) than untreated minesoil, and as a result, fly ashes had much greater plant available water retention than minesoil. Silty textures and lower saturated hydraulic conductivity values for fly ash indicate that it may be more susceptable to erosion than minesoils. When applied to a pyritic minesoil, alkaline fly ashes with high neutralization potential had more favorable long-term effects on soil properties than the more neutral fly ash.