Drum Mill / Rod Mill TM 300 XL RETSCH. The Drum Mill TM 300 XL allows powerful grinding of large quantities. . The grinding process is performed either in dry or wet conditions. . glass, gypsum, hair, hydroxyapatite, iron ore, kaolin, limestone, metal oxides, minerals, . larger grinding ball resp. rod diameters are used, smaller diameters lead to a substantially.