Six composite filter fly, bottom, and dump ash samples, each taken from Obilic power plant, were subjected to the sequential extraction procedure comprised of five phases. Iron silicates, alumosilicates not containing iron and silicates not containing iron nor aluminum, as well as a form of aluminum not containing silicon, are established as substrates dissolved in the fifth phase of extraction. Alumosilicates and mixed oxides of iron and manganese are dissolved in the third phase of extraction. Association patterns and distribution of trace and major elements with substrates as well as environmental consequences of such distribution were established and discussed.