Ermelo (previously Eastern Transvaal coalfield) Five major developed coal seams are the E, D, Clower and C. Ermelo (GlenfillanWakkerstroom) Targas, Coking, Dundas, Upper Dundas, Gus, Alfred and Eland. 3. Klip River Bottom seam and Top seam. Top seam better developed than Bottom seam. 4.