The ore is fed into the elevated end of the trommel. Gyratory separators can also separate dry and wet materials like trommel screens. The trommel screen has many different configurations. They also cause less noise than trommel screens and require less head room. Her volume of war poetry, "Neben der Trommel" ("loosely, "Beside the drum"") followed in 1915. Roller screens are preferred to trommel screens when the feed rate required is high. First, a large trommel separates materials like appliances and fabrics. One of the main process characteristics of interest is the screening rate of the trommel. A trommel is used to separate materials by size. The remaining materials, after simple physical separation (trommel screen) has several valuable uses. Gold was recovered in a rotating long trommel screen with diameter and 12.5% grade. In addition, trommel screens are used for the treatment of wastewater. Trommel screens are used widely in industries for its efficiency in material size separation. Trommel screens are also used for the grading of raw materials to recover valuable minerals.