This resource is recommended for teaching students to develop site-specific solutions in regards to the environmental challenges they experience in their environment. In this case, the problem of coal ash disposal and pollution is addressed. There is a contradiction in the diameter of a coal ash, especially fly ash. It is stated in the resource that fly ash, a fine, silt-like particle from coal ash is about 0.5-300 micrometers. This is not true as the maximum size of fly ash is 100 micrometers or less in diameter, depending on how the coal was combusted. Anything more than this is a bottom ash.